Animal skin substrate treatment apparatus and method
[0001] This invention relates to an improved method and apparatus for the treatment of
animal skin substrates which employs a solid particulate material (also referred to herein as
"a multiplicity of solid particles"). Particularly, the invention provides a method and apparatus
for separating the solid particulate material from the animal skin substrates during the
treatment process. In preferred embodiments, the animal skin substrates can be a hide or a
pelt. The animal skin substrates can be subjected to one or more processes to form leather.
BACKGROUND
[0002] Current methods for treating or processing animal skin substrates can necessitate
the use of vast quantities of water. For example, in treatment methods wherein the animal
skin substrate comprises a hide, typically 30 kg of water is required per kg of hide. Large
volumes of water can be needed in order to remove unwanted materials from the animal skin
(such as those that are liable to decomposition) and also in subsequent steps of the process
which involve chemical modification to confer certain properties on the substrate. Chemical
modification of the substrate can be carried out for the purpose of, inter alia, preserving,
waterproofing, colouring and/or providing any desired textural or aesthetic qualities. The
various steps described above will generally be performed in the presence of a treatment
formulation comprising one or more components.
[0003] Due to the large amounts of water relative to the weight of animal substrate, current
treatment processes known in the art also require a proportionate quantity of chemicals used
in the treatment formulation to ensure an effective treatment of the substrate within an
acceptable timeframe. Consequently, excessive amounts of polluting and environmentally
damaging effluents can be produced from such processes. Furthermore, long process times
are necessary.
[0004] Many of the methods for preparing animal skin substrates for human use still
remain predominantly based on traditional processes and there have been few advances in
recent years. For example, methods for the processing and manufacturing of leather have
remained largely unchanged for 75 years. EP0439108 filed in 1991 and directed to a
process using carbon dioxide for deliming of hides, discloses an example of one of the few
recent developments in this field.
[0005] Prior to the innovations disclosed herein, the inventors have previously addressed
the problem of reducing water consumption in a domestic or industrial cleaning method.
Thus, in WO-A-2007/1 28962 there is disclosed a method and formulation for cleaning a
soiled substrate, the method comprising the treatment of the moistened substrate with a
formulation comprising a multiplicity of polymeric particles, wherein the formulation is free of
organic solvents. The soiled substrate may be wetted so as to achieve a substrate to water
ratio of between 1:0. 1 to 1:5 w/w, and optionally, the formulation may additionally comprise
at least one cleaning material, which typically comprises a surfactant, which most preferably
has detergent properties. The soiled substrate may comprise a textile fibre. The polymeric
particles may, for example, comprise particles of polyamides, polyesters, polyalkenes,
polyurethanes or their copolymers, a particular example being nylon beads.
[0006] Following the development of this method the present applicant further devised an
apparatus specially adapted to clean soiled substrates by virtue of recirculation of the
polymeric particles. Thus, in WO201 1/098815, the present applicant provided an apparatus
for use in the cleaning of soiled substrates, the apparatus comprising housing means having
a first upper chamber with a rotatably mounted cylindrical cage mounted therein and a
second lower chamber located beneath the cylindrical cage, and additionally comprising at
least one recirculation means, access means, pumping means and a multiplicity of delivery
means, wherein the rotatably mounted cylindrical cage comprises a drum having perforated
side walls where up to 60% of the surface area of the side walls comprises perforations
comprising holes having a diameter of no greater than 25.0 mm.
[0007] Although the method and apparatus disclosed in WO2007/1 28962 and
WO20 11/098815 provided considerable improvements for the cleaning of soiled substrates
these developments were primarily applicable to the field of laundry wherein the substrate
typically comprises textile fibre garments. The method and apparatus of WO2007/1 28962
and WO201 1/098815 (so-called "bead cleaning" technologies) were not however specifically
adapted or optimised for the treatment of animal skin substrates.
[0008] The present disclosure therefore seeks to provide an apparatus and method for use
in the treatment of animal skin substrates that can ameliorate or overcome the above-noted
problems associated with the prior art. Particularly, there is desired a method and apparatus
for treating an animal skin substrate which requires less water than the processes of the
prior art and that reduces the volume of polluting and hazardous effluent produced.
Furthermore, there is desired a method and apparatus for treating an animal skin substrate
with a solid particulate material that provides an effective means of separating the solid
particulate material from the substrate.
BRIEF SUMMARY OF THE DISCLOSURE
[0009] According to a first aspect of the present invention there is provided an apparatus
for treating one or more animal skin substrates with a multiplicity of solid particles and
treatment liquor comprising:
a rotatably mounted drum comprising an internal volume having a first portion defining a
treatment volume for retaining said animal substrates and a second portion defining a
collecting volume, wherein the side-walls of said drum are not perforate;
one or more inlets for introducing solid particles and treatment liquor into said treatment
volume;
a partition separating said treatment volume from said collecting volume wherein said
partition allows free passage of solid particles from the treatment volume to the collecting
volume and prevents the passage of the substrate(s) therethrough;
a circulation path for conveying said solid particles from the collecting volume to the
treatment volume; and
a pumping device arranged to pump solid particles and said treatment liquor along a portion
of said circulation path.
[0010] Advantageously, the present invention employs a multiplicity of solid particles (also
referred to herein as a solid particulate material) to confer a more uniform and enhanced or
effective mechanical action on the animal skin substrate when the drum is rotated. This can
reduce the duration of the necessary treatment cycle providing improvements in efficiency
over processes of the prior art. By virtue of the inclusion of the solid particles, the invention
facilitates the use of only limited amounts of treatment liquor (which typically comprises
water) thereby offering significant environmental benefits compared to standard processes
commonly employed in this field. As the quantity of treatment liquor needed by the invention
is significantly reduced, the amount of chemicals relative to a given quantity of substrate in
order to provide an effective treatment of the animal skin substrates is decreased.
Furthermore, the partition of the invention provides an efficient means of separating solid
particles from the animal skin substrates. Effective separation of solid particles from the
substrates improves the efficiency and/or efficacy of the treatment and increases the number
of available particles for use in an ongoing treatment cycle or for subsequent treatment
cycles. In some advantageous embodiments, the invention is able to achieve separation of
solid particles from the animal skin substrates with a separation efficiency of greater than
99%.
[0011] As described herein, "treatment liquor" comprises a liquid medium used in the
apparatus or treatment process of the invention. Preferably said treatment liquor can
comprise water or water when combined with at least one treatment agent and/or any further
additives as detailed further hereinbelow.
[0012] Preferably, said rotatably mounted drum comprises a multiplicity of solid particles
therein.
[0013] Preferably, said circulation path is external to said drum.
[0014] Preferably, the or each animal skin substrate is a hide or a pelt. The treatment
process using the apparatus of the invention can be a process in the production of leather.
The hide or pelt can be subjected to one or more additional process steps in the production
of leather before or after the treatment process using the apparatus of the invention. The
hide or pelt can be a processed or unprocessed animal skin substrate.
[0015] Preferably, the axis of rotation of the drum passes through both the treatment
volume and the collecting volume and no part of said axis of rotation is contained within both
the treatment volume and the collecting volume.
[0016] Preferably, the circulation path provides a flow of solid particles from the collecting
volume to the treatment volume and then to the collecting volume. Thus the solid particles
can move through the treatment volume to the collecting volume via the partition.
[0017] Preferably, the circulation path provides a flow of treatment liquor from the
collecting volume to the treatment volume and then to the collecting volume. Thus the
treatment liquor can move through the treatment volume to the collecting volume via the
partition.
[0018] Preferably, said apparatus comprises a processing system in said circulation path
wherein said processing system receives said treatment liquor and said solid particles from
the collecting volume of said drum.
[0019] Preferably, said processing system comprises a separator configured to separate at
least a portion of said treatment liquor from said solid particles.
[0020] Thus, advantageously, the separation of treatment liquor from the solid particles
promotes their effective re-use.
[0021] Preferably, said apparatus comprises a storage vessel for retaining said solid
particles and a dispenser to introduce said solid particles to said treatment volume. The
storage vessel can receive solid particles from said circulation path such as from the
processing system.
[0022] Preferably, a first portion of the circulation path comprises a conduit having an inlet
disposed proximate the lowermost part of the collecting volume, the conduit extending from
said collecting volume. Preferably the conduit extends from said collecting volume externally
of the drum. The conduit can extend to the processing system.
[0023] Preferably, a first such conduit can be provided for conveying solid particles. In
some preferred embodiments a second such conduit can be provided for conveying
treatment liquor. In other arrangements one or more such conduits can convey both
treatment liquor and solid particles.
[0024] Preferably, the drum has an upper portion comprising at least one inlet to introduce
said solid particles into said treatment volume and at least one inlet for receiving treatment
liquor into said treatment volume.
[0025] Preferably, said dispenser communicates with said at least one inlet of said upper
portion to introduce said solid particles into said treatment volume.
[0026] Preferably, said apparatus comprises a conduit extending from an outlet of the
processing system wherein said conduit is connected to an inlet of the upper portion of the
drum. The conduit can convey solid particles to the treatment volume of the drum. The
conduit can convey treatment liquor to the treatment volume of the drum. The conduit can
convey both treatment liquor and solid particles to the treatment volume of the drum.
[0027] Preferably, said processing system comprises a device for removing residual
treatment liquor and deposits from said solid particles. Particularly, said deposits can be
derived from said animal skin substrates. The processing system can further comprise a
device that can carry out one or more washing or rinsing stages. In this way residual
treatment liquor and deposits can be removed from the solid particles before they are
conveyed to the storage vessel or re-introduced to the treatment volume of the drum.
[0028] Preferably, said processing system comprises one or more outlets for discharging
treatment liquor and/or unwanted matter produced during the treatment process.
[0029] Preferably, said drum comprises a closure moveable between an open position and
a closed position wherein when said closure is moved to said open position free passage of
solid particles and fluids into the collecting volume from the treatment volume is permitted
and wherein when said closure is moved to said closed position solid particles are prevented
from passing into the collecting volume from the treatment volume whilst the passage of
fluids into the collecting volume from the treatment volume is permitted. Thus, when said
closure is moved to a closed position, solid particles are prevented from entering the
collecting volume but fluids such as treatment liquor can still enter the collecting volume and
proceed along the circulation path.
[0030] Advantageously, the use of such a closure can limit the quantity of solid particles
accumulating in the collecting volume thereby reducing the possibility of blocking the
circulation path and/or damaging the pumping device.
[0031] Alternatively, said drum may preferably comprise a closure moveable between an
open position and a closed position wherein when said closure is moved to said open
position free passage of solid particles and fluids into the collecting volume from the
treatment volume is permitted and wherein when said closure is moved to said closed
position any solid particles and fluids are retained in the treatment volume. Preferably when
the closure is moved to a closed position, solid particles and treatment liquor are thus
prevented from entering the collecting volume and proceeding along the circulation path.
[0032] Advantageously, the drum can thus include a closure to further facilitate the use of
lower levels of treatment liquor in the apparatus.
[0033] Preferably, said drum is configured to rotate about a horizontal axis or an axis which
is inclined to the horizontal.
[0034] Preferably, said drum is configured to rotate about an axis which is inclined to the
horizontal. Rotation of the drum about such an inclined axis during the treatment process
can promote separation of the solid particles from the animal substrates. The conduit of the
first portion of the circulation path includes a portion which extends from the interior to the
exterior of the drum and the axis of which is coincident with the axis of rotation of said drum.
[0035] In embodiments wherein said drum is configured to rotate about an axis which is
inclined to the horizontal it is preferred that a major portion of the treatment volume extends
above the collecting volume.
[0036] Said drum may be inclined at an angle of from about 1° to about 45°, more
preferably 1° to about 30° and most preferably from about 5° to about 25° with respect to the
horizontal. The inventors consider that an incline that is too steep causes the animal skin
substrate(s) to slump against one side of the drum whereas a drum configured to rotate
about an axis with no or minimal inclination provides reduced efficiency in terms of particle
separation.
[0037] Preferably, said pumping device is arranged in the circulation path external to the
drum. Preferably, said pumping device can be located downstream, particularly immediately
downstream, of said collecting volume.
[0038] As noted above, the apparatus of the invention includes a partition which separates
the treatment volume from the collecting volume. There exists no gap between the partition
and a wall of the drum through which the animal skin substrates can pass from the treatment
volume to the collecting volume.
[0039] Preferably, said partition comprises a plurality of apertures. The plurality of
apertures are sized to allow passage of said solid particles therethrough and prevent the
passage of said animal skin substrates therethrough.
[0040] Preferably, said partition is in the form of a perforate or reticulate screen.
[0041] Preferably, said apertures have a maximum dimension of from about 2 to 125mm,
from about 2 to 100mm, from about 2 to 75mm, from about 2 to 50mm, from about 2 to
about 35mm, from about 2 to 26mm, from about 2 to 25mm, from about 2 to about 10mm or
from about 6 to about 10mm. In some embodiments said apertures have a maximum
dimension of about 10mm or about 5mm or about 2mm. In some embodiments said
apertures have a maximum dimension of from about 26mm to about 125mm.
[0042] The partition is configured to support the weight of said animal skin substrates. In
one typical arrangement the treatment volume contains animal substrates with a combined
weight of up to 50,000kg. The treatment volume may contain animal substrates with a
combined weight of from about 50 to about 50,000kg, from about 500 to about 30,000kg,
from about 1000kg to about 25,000kg, from about 2000 to about 20,000kg, from about 2500
to about 10,000kg.
[0043] Preferably, said partition comprises metal, metal alloy, plastic, fibreglass, composite
or polymeric materials. Typically, the partition is corrosion resistant. Particularly, said
partition is resistant to any chemicals or additives with corrosive properties that may be
present in the treatment liquor. Preferably, said partition comprises steel, especially stainless
steel.
[0044] Preferably, the partition is arranged to be substantially perpendicular to the axis of
rotation of said drum.
[0045] Preferably, the multiplicity of solid particles can be re-used one or more times for
treatment of the animal skin substrates in, with or by the apparatus of the invention. The
circulation path facilitates re-use of the solid particles as does the storage vessel. Preferably,
the solid particles can be re-used at least two, three, four, five or more times, such as 10, 20,
50 or 100 or more times, for treatment of the animal skin substrates in, with or by the
apparatus of the invention. The solid particles are typically not re-used more than 10,000 or
more than 1,000 times.
[0046] Preferably, said solid particles have an average particle diameter of from 1mm to
100mm. In some embodiments the solid particles have an average particle diameter of from
1 to 50mm or 1 to 25mm or 1 to 15mm or 1 to 10mm or 2 to 8mm or 4 to 8mm or 5 to 7mm.
[0047] Preferably, said solid particles have a length of from 1mm to 100mm. The solid
particles may have a length of from 1 to 50mm or 1 to 25mm, or from 1 to 15mm or from 1 to
10mm, or from 2.0 to 8.0mm, or from 4.0 to 7.0mm, or from 5.0 to 7.0mm, or from 1.0 to
5.0mm or from 2.5 to 4.5mm.
[0048] The skilled person will however understand that the diameter and length of the solid
particles are to be selected in accordance with the maximum dimension of the apertures in
the partition to ensure that the solid particles can pass freely through the screen.
[0049] Preferably, the solid particles are spheroidal, spherical or ellipsoidal.
[0050] Preferably, the solid particles can comprise a multiplicity of polymeric particles, a
multiplicity of non-polymeric particles or a mixture of a multiplicity of polymeric and nonpolymeric
particles.
[0051] Preferably, the polymeric or non-polymeric particles can comprise or be in the form
of beads.
[0052] Preferably, the polymeric particles have an average density of about 0.5 g/cm3 to
about 3.5 g/cm3 and preferably about 0.5 to 2.5g/cm3. In other embodiments the polymeric
particles have an average density of 0.5 to less than 1g/cm3.
[0053] Preferably, the polymer in the polymeric particles can comprise polyalkenes,
polyamides, polyesters, polysiloxanes, polyurethanes or copolymers thereof.
[0054] Tthe polymer in the polymeric particles can comprise polyalkenes or polyurethanes,
or copolymers thereof.
[0055] The polymer in the polymeric particles can comprise polyamide or polyester or
copolymers thereof.
[0056] Said polyamide can comprise nylon. The polyamide can comprise Nylon 6 or Nylon
6,6.
[0057] The polyester can comprise polyethylene terephthalate or polybutylene
terephthalate.
[0058] Preferably, the non-polymeric particles can comprise ceramic material, refractory
material, igneous, sedimentary or metamorphic minerals, composites, metal, glass or wood.
[0059] Preferably, the non-polymeric particles have an average density of 0.5 to 20 g/cm3,
more preferably from 2 to 20g/cm3, especially from 4 to 15g/cm3 and most especially from 4
to 10g/cm3.
[0060] Preferably, said drum has a capacity of from 500 to 200,000 litres.
[0061] Preferably, said treatment volume comprises at least 0.5%, at least 1%, at least 5%,
at least 10%, at least 20%, at least 30%, at least 40% or at least 50% of said internal volume
of said drum. Preferably, said treatment volume comprises at least 60%, preferably at least
70%, more preferably at least 80% and most preferably at least 90% of the internal volume
of said drum. Preferably, said treatment volume comprises not more than 99.5% of the
internal volume of said drum.
[0062] Preferably, said treatment volume comprises from about 0.5% to about 99.5%, from
about 1% to about 99%, from about 5% to about 95%, from about 10% to about 90%, from
about 20% to about 80%, from about 30% to about 70%, from about 40% to about 60% of
the internal volume of said drum. Alternatively, it is preferred that said treatment volume
comprises from about 0.1% to about 10% of the internal volume of said drum.
[0063] Preferably, said collecting volume comprises not more than 30% of said internal
volume of said drum. Preferably, said collecting volume comprises not more than 25%,
preferably not more than 20%, more preferably not more than 15%, yet more preferably not
more than 10% and most preferably not more than 5% of the internal volume of said drum.
Preferably, said collecting volume comprises at least 0.5% of the internal volume of said
drum.
[0064] Preferably, said collecting volume comprises from about 0.5% to about 99.5%, from
about 1% to about 99%, from about 5% to about 95%, from about 10% to about 90%, from
about 20% to about 80%, from about 30% to about 70%, from about 40% to about 60% of
the internal volume of said drum. Preferably, said collecting volume comprises from about
0.5% to about 10% of the internal volume of said drum.
[0065] According to a second aspect of the present invention there is provided a method of
separating a multiplicity of solid particles from one or more animal skin substrates during a
treatment process comprising:
agitating said animal skin substrates with a multiplicity of solid particles and treatment liquor
in a treatment volume of a rotatably mounted drum wherein the side-walls of said drum are
not perforate,
said drum having a collecting volume separated from the treatment volume by a partition,
wherein said method further comprises allowing the solid particles and treatment liquor to
pass through the partition from the treatment volume to the collecting volume whilst retaining
said animal skin substrates in the treatment volume.
[0066] Advantageously, the method of the second aspect of the invention provides an
effective means of separating solid particles within the drum thereby enhancing the
efficiency of the treatment as additional steps to disengage residual solid particles from the
substrate are greatly simplified or are no longer needed.
[0067] The rotatably mounted drum of the second aspect of the invention can comprise
any of the features or any permitted combination of features stated above with respect to the
rotatably mounted drum of said first aspect of the invention.
[0068] Preferably, the axis of rotation of the drum is configured to pass through both the
treatment volume and the collecting volume and no part of said axis of rotation is contained
within both the treatment volume and the collecting volume.
[0069] Preferably, said method comprises circulating said treatment liquor from said
collecting volume to said treatment volume to provide a flow of treatment liquor through the
treatment volume and continuing agitation of said animal skin substrates in said drum for a
predetermined period or until a desired separation of solid particles from said animal skin
substrates is achieved.
[0070] Preferably, said method further comprises conveying said solid particles and said
treatment liquor from the collecting volume, separating at least a portion of said treatment
liquor from said solid particles and re-introducing said solid particles into said treatment
volume. The method can preferably further comprise agitating said animal skin substrates
with said solid particles and treatment liquor in the treatment volume in a subsequent
agitation step.
[0071] Preferably, said method comprises the steps of:
i) introducing treatment liquor into said treatment volume and agitating said animal skin
substrates with said solid particles and said treatment liquor in the treatment volume for a
first agitation step;
ii) allowing said treatment liquor to pass through the partition to the collecting volume and
conveying said treatment liquor from the collecting volume along a circulation path;
iii) re-introducing said treatment liquor from said circulation path into said treatment volume.
[0072] The above-noted steps i) ii) and iii) of the method may be performed separately,
simultaneously or they may overlap in time (synchronously/contemporaneously).
[0073] Preferably, said circulation path is external to said drum.
[0074] Thus, advantageously, the method of the invention permits re-use of the treatment
liquor in more than one phase or for multiple agitation steps with the animal substrates within
a given treatment cycle.
[0075] Preferably, said method further comprises separating at least a portion of said
treatment liquor received from the collecting volume from said solid particles before re
introducing said treatment liquor from said circulation path into said treatment volume.
[0076] Preferably, said method comprises extracting effluent and/or unwanted matter from
the treatment liquor received from the collecting volume before re-introducing said treatment
liquor into said treatment volume.
[0077] Preferably, said method comprises the steps of:
i) introducing said solid particles into said treatment volume and agitating said animal skin
substrates with said solid particles and said treatment liquor in the treatment volume for a
first agitation step;
ii) allowing said solid particles to pass through the partition to the collecting volume and
conveying said solid particles from the collecting volume along a circulation path external to
the drum;
iii) re-introducing said solid particles into said treatment volume from said circulation path
and agitating said animal skin substrates with said solid particles and treatment liquor in the
treatment volume for a subsequent agitation step.
[0078] The above-noted steps i) ii) and iii) of the method may be performed separately,
simultaneously or they may overlap in time (synchronously/contemporaneously).
[0079] Preferably, said circulation path is external to said drum.
[0080] Thus, advantageously, the method of the invention permits re-use of the solid
particles in more than one phase or for multiple agitation steps with the animal skin
substrates within a typical treatment cycle.
[0081] Preferably, said method further comprises separating at least a portion of said
treatment liquor from said solid particles before re-introducing said solid particles from said
circulation path into said treatment volume for a subsequent agitation step.
[0082] Preferably, said method further comprises subjecting said solid particles to a
cleaning operation using a cleaning formulation before re-introducing said solid particles into
said treatment volume for a subsequent agitation step.
[0083] Preferably, said method comprises conveying said solid particles from the collecting
volume to a processing system and performing said cleaning operation in said processing
system.
[0084] Preferably, said method comprises draining said treatment liquor from the drum and
subjecting said solid particles to said cleaning operation within said drum before re
introducing said solid particles into said treatment volume for a subsequent agitation step.
[0085] Thus, advantageously, subjecting the solid particles to a cleaning operation can
extend their usable lifetime for use multiple agitation steps.
[0086] Preferably, said drum comprises a closure moveable between an open position and
a closed position wherein when said closure is moved to said open position free passage of
solid particles and fluids into the collecting volume from the treatment volume is permitted
and wherein when said closure is moved to said closed position solid particles are prevented
from passing into the collecting volume from the treatment volume whilst the passage of
fluids into the collecting volume from the treatment volume is permitted,
wherein said method comprises moving said closure from said open position to said closed
position or moving said closure from said closed position to said open position at one or
more points during the treatment process.
[0087] Alternatively, said drum can preferably can comprise a closure moveable between
an open position and a closed position wherein when said closure is moved to said open
position free passage of solid particles and fluids into the collecting volume from the
treatment volume is permitted and wherein when said closure is moved to said closed
position any solid particles and fluids in the treatment volume are retained in the treatment
volume, wherein said method comprises agitating said animal skin substrate(s) and said
solid particles in said drum for a predetermined period with said closure in said closed
position and moving said closure to an open position when said predetermined period has
elapsed.
[0088] Preferably, said method further comprises introducing treatment liquor into said
drum when said predetermined period has elapsed.
[0089] Preferably, said drum is caused to rotate about an axis which is inclined to the
horizontal for at least a portion of said treatment process. Preferably said drum is caused to
rotate about an axis which is inclined to the horizontal for the duration of said treatment
process.
[0090] Preferably, said drum is caused to rotate at a speed of from about 1 to about 50
rpm, preferably from about 1 to about 30 rpm, and preferably from about 1 to about 15 rpm.
[0091] Particularly wherein the treatment process is a beamhouse or a tanning or a
retanning or a fatliquoring or a dyeing process, the drum may be caused to rotate at a speed
of from about 3 to about 14 rpm. Where the treatment process is a beamhouse or a tanning
process or a retanning or a fatliquoring or a dyeing process, the drum may be caused to
rotate at a speed of from about 5 and 13 rpm. Where the treatment process is a beamhouse
or a tanning or a retanning or a fatliquoring or a dyeing process, the drum may be caused to
rotate at a speed of from about 8 and 12 rpm.
[0092] Particularly wherein the treatment process is a beamhouse process, the drum may
be caused to rotate at a speed of from about 9 to about 14 rpm.
[0093] Particularly wherein the treatment process is a beamhouse or a tanning or a
retanning or a fatliquoring or a dyeing process, the drum may be caused to rotate at a speed
of not more than 15 rpm or not more than 13 rpm, or not more than 12 rpm, or not more than
10 rpm, or not more than 8 rpm, or not more than 6 rpm, or not more than 5 rpm, not more
than 4 rpm, not more than 3 rpm or not more than 1 rpm.
[0094] Preferably, said treatment volume has an ullage volume of at least 10% by volume.
Preferably said treatment volume has an ullage volume of at least 20% by volume, and most
preferably from 30 to 70% or from 30 to 60% by volume. These ullage volumes can be
effective in order to provide for efficient mixing whilst maximising the utilisation capacity of
the apparatus.
[0095] Preferably, the or each animal skin substrate is a hide or pelt.
[0096] Preferably, said treatment process is a tannery process.
[0097] Preferably, said tannery process is selected from one or more of cleaning, curing,
beamhouse treatments, tanning, re-tanning, fat liquoring, enzyme treatment, dyeing and dye
fixing.
[0098] Typical beamhouse treatments include soaking, liming, deliming, reliming,
unhairing, fleshing, bating, degreasing, scudding, bating, pickling and depickling.
[0099] Preferably, said treatment process is a process used in the production of leather.
[00100] Preferably, said process used in the production of leather includes one or more of:
curing, beamhouse treatments , fat liquoring, pretanning, tanning, retanning, tawing,
crusting and dyeing.
[00101] Preferably, the treatment liquor is aqueous. The treatment liquor can comprise at
least 0.1 % w/w water, orat least 1% w/w water, or at least 5% w/w water, or between 5%
and 99.9% w/w water. In further embodiments the treatment liquor comprises not more than
99.9% w/w water. Minor amounts of organic solvents (preferably less than 10% w/w, more
preferably less than 5% w/w) can be present in the treatment liquor however they are
preferably absent.
[00102] Alternatively, the treatment liquor is substantially free from water except for that
originating from the or each animal substrate. Thus the treatment liquor can be substantially
free from water except from that derived from any latent fluid present within the animal skin
substrate(s) itself. Thus, water can be carried into the drum originating from the animal skin
substrate. In further embodiments the treatment liquor is substantially free from water.
[00103] Preferably, said treatment liquor comprises at least one treatment agent selected
from tanning agents, re-tanning agents and tannery process agents.
[00104] Preferably, said treatment liquor comprises at least one colourant.
[00105] Preferably, said colourant is selected from one or more dyes, pigments, optical
brighteners or mixtures thereof.
[00106] Preferably, said solid particles are re-used one or more times in the same treatment
method or for the treatment of further animal skin substrates in subsequent treatments in
accordance with the method of the second aspect of the invention. Such re-use or re-uses
can preferably be in an apparatus according to the first aspect of the invention. Thus,
preferably, the solid particles are used in a plurality of agitation steps with animal skin
substrates in accordance with the method as described herein.
[00107] Preferably, the method further comprises extracting the animal skin substrate from
the drum and subjecting the substrate to a secondary solid particulate material removal
process for the separation of residual solid particulate material from the animal skin
substrate.
[00108] Preferably, the secondary solid particulate material removal process comprises
passing the animal skin substrate between opposed rotating cylindrical brushes or subjecting
the solid particulate material on the animal skin substrate to removal by suction with a
suction device.
[00109] Preferably, said method of said second aspect of the invention is performed using
the apparatus of said first aspect of the invention. The method of the second aspect of the
invention can thus be carried out in an apparatus comprising any of the features or any
permitted combination of features described above in relation to the first aspect of the
invention.
[001 10] In accordance with a third aspect of the invention there is provided a method of
treating one or more animal skin substrates wherein said method comprises the method of
separating a multiplicity of solid particles from one or more animal skin substrates according
to the second aspect of the invention. The method of treating said one or more animal skin
substrates can thus comprise treating the animal skin substrate(s) by performing any of the
treatment processes described above in relation to the second aspect of the invention or any
of the treatment processes described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[001 11] For a better understanding of the invention and to show how the same may be
carried into effect, reference will be made, by way of example only, to the following drawings,
in which:
Figure 1 is a schematic view of the apparatus according to an embodiment of the
invention containing an animal skin substrate (S);
Figure 2 is an image showing a further apparatus for removing solid particulate
material from animal skin substrates according to an embodiment of the invention;
Figure 3 shows a schematic front view of a further apparatus for removing solid
particulate material from animal skin substrates according to an embodiment of the
invention.
DETAILED DESCRIPTION
[001 12] The apparatus and method of the invention employs a solid particulate material
(also referred to herein as a multiplicity of solid particles) for use in the treatment of animal
skin substrates. The use of the apparatus and method of the invention can enable the
modification or transformation of the properties of the animal skin substrate prior to further
treatment or processing of the substrate to form a manufactured article. The invention thus
encompasses treatment steps performed on hides, pelts and the like before the substrate is
prepared for consumer, domestic and/or industrial purposes (for example, in clothing (e.g.
shoes and trainers), upholstery or automotive industries).
[001 13] Notably, the treatment performed by the invention is distinguished from processes
such as "laundering" wherein the substrate is typically a finished garment or fabric (being a
manufactured article) and wherein the treatment merely relates to removing stains, soil and
other unwanted matter from the surface of the substrate. Separation of solid particles from
animal skin substrates is complicated by the texture and composition of the substrate which
typically comprises a soft, fleshy tissue. The soft, fleshy nature of such substrates increases
the likelihood that solid particles, when agitated with the substrate in a rotating drum, are
more likely to adhere to the substrate surface or become embedded therein. The present
invention therefore seeks to provide a treatment apparatus and method that remedies the
deficiencies of the water intensive processes for treating animal skin substrates of the prior
art and which also provides a practical and effective way of separating solid particles from
the substrate.
[001 14] As shown in Figure 1, the treatment process carried out by the invention is
performed in an apparatus 100 comprising a drum 10. In use of the apparatus 100, the drum
10 contains the animal skin substrates (S) being treated. The drum 10 is mounted for
rotation about an axis and the animal substrates are brought into contact with solid
particulate material, treatment liquor including any treatment agents and/or further additives
as may be desirable within the drum 10. The drum 10 may be mounted for rotation about a
horizontal axis or, alternatively, an axis which is inclined to the horizontal. Preferably the
drum 10 is mounted about an axis inclined to the horizontal as this advantageously promotes
enhanced separation of the solid particulate material from the substrate surface as the drum
rotates. In such embodiments a major portion of the treatment volume preferably extends
above the collecting volume. Typically the drum is inclined at an angle of from about 1° to
about 45°, more preferably 1° to about 30° and most preferably from about 5° to about 25°
with respect to the horizontal. In some embodiments the drum is inclined at angle of about
14° with respect to the horizontal.
[001 15] Alternatively, the drum 10 is mounted about a vertical axis or, more preferably, an
axis which is inclined with respect to the vertical. This variant of the apparatus 100 can
promote separation of the solid particulate material from the substrate surface as the drum
rotates. In some embodiments the drum is inclined at an angle of between about 1° and
about 89°, from about 89° to about 60°, from about 85° to about 65° with respect to the
vertical. Preferably, the drum is inclined at angle of about 76° with respect to the vertical.
[001 16] The drum 10 can be mounted such that the angle of inclination of the axis of
rotation can be varied. This can enable a mechanical action on the animal skin substrate of
variable strength or intensity during the course of the treatment process.
[001 17] The drum 10 has an access means 12 through which the animal skin substrate to
be treated can be loaded into the drum 10 and through which the treated substrate can be
removed after the treatment process. The access means 12 can be in the form of a door
which may be conveniently hinged or slidably mounted for movement between open and
closed configurations. When the door 12 is moved to an open position, access is permitted
to place one or more animal skin substrates for treatment inside the drum 10. When the
door 12 is moved to a closed position, the apparatus 100 is sealed. Alternatively, the animal
skin substrate can be loaded via an opening 19 disposed at one end of the drum 10.
[001 18] The drum 10 is defined by a side wall 10a which encloses the internal volume
containing the animal substrates together with portions of the solid particulate material and
treatment liquor. Figure 1 illustrates a drum 10 having a cylindrical side wall 10a, however
non-cylindrical drums with more than one side wall are also permissible. The internal volume
of the drum 10 is further defined between a lower end wall portion 10b and an upper end
wall portion 10c. Unlike the apparatus disclosed in WO201 1/098815 and other equivalent
bead cleaning machines of the prior art, the side wall(s) of drum 10 are not perforate and are
thus fluid retaining. Instead, and as will be clear from the description, treatment liquor and
solid particulate material are preferably able to enter and exit the internal volume of the drum
10 from first and second end regions of the drum 10 .
[001 19] The internal surface of the side wall 10a of the drum 10 can include means to
encourage further agitation of the substrates during the treatment process. The internal
surface of the side wall 10a can include one or more generally spiral or helical fins 11 to
facilitate agitation of the animal skin substrate as the drum 10 rotates. The inclusion of spiral
or helical fins are particularly useful in wherein the drum 10 is mounted about an axis that is
inclined with respect to the horizontal. Alternatively, the drum 10 can include one or more
protrusions projecting inwardly from the internal surface of the side wall 10a. Said
protrusions can be in the form of pegs such as wooden or plastic dowels. The protrusions
can be in the form of planar shelves that run substantially parallel to the axis of rotation of
the drum 10. The above-noted one or more protrusions can be particularly suitable for drums
mounted about a horizontal axis.
[00120] The drum 10 can be of the size which is to be found in most tanneries for the
processing of animal hides and can typically have a capacity in the region of 500 to 40,000
litres. Typical size of a drum 10 to process animal hides in this range would generally
comprise a cylinder with a diameter in the region of 0.1 to 10m, preferably from 0.5 to 5m,
and a length of between 0.1 and 10m, preferably between 0.5 and 5m. Larger drum sizes
are however permissible and can have a capacity of up to 200,000 litres. Preferably the
drum 10 has a capacity of greater than 100 litres and more preferably greater than 1000
litres. Said drum 10 may have a capacity of from 500 to 200,000 litres, preferably of from
500 to 135,000 litres, more preferably from 500 to 75,000 litres and most preferably from 500
to 40,000 litres.
[00121] The drum 10 further comprises an internal volume having a first portion defining a
treatment volume 14 and a second portion defining a collecting volume 20. The treatment
volume 14 defines the region of the drum 10 in which the animal substrates are contained
and wherein said animal substrates are agitated with treatment liquor (plus any treatment
agents and/or any further additives) and the solid particulate material. The treatment volume
14 can be defined in an upper portion of the drum 10 and the collecting volume 20 can be
defined in a lower portion of the drum 10.
[00122] The treatment volume 14 can be substantially larger than the collecting volume 20.
In some preferred arrangements, the treatment volume 14 comprises about 90% of the
internal volume of the drum. The collecting volume 20 can comprise about 10% of the
internal volume of the drum. In alternative embodiments, and particularly those adapted to
use low quantities of treatment liquor, the collecting volume 20 can be larger than the
treatment volume 14.
[00123] The treatment volume 14 of the drum 10 is sufficiently large so to accommodate the
animal skin substrate to be treated, the solid particulate material and treatment liquor, whilst
still providing sufficient ullage to allow for efficient circulation and mixing of the materials
when agitated during the treatment process. Typically, allowance should be made for ullage
values of at least 10% by volume, preferably at least 20% by volume, and most preferably
from 30 to 70% or 30 to 60% by volume in order to provide for efficient mixing whilst
maximising the utilisation capacity of the treatment process. Loading of the animal skin
substrates, solid particles and treatment liquor (plus any additives) in the apparatus 100 can
thus be carried out to accommodate the above-noted ullage values.
[00124] The apparatus 100 further comprises one or more inlets 16 to deliver various
components used in the treatment process (i.e. the solid particulate material, treatment
liquor, treatment agents and/or any further additives) to the drum 10. Preferably, said one or
more inlets 16 are arranged to deliver said components into the treatment volume 14. The
upper portion of the drum 10 can therefore conveniently comprise said one or more inlets 16.
In some embodiments the apparatus 100 comprises a plurality of inlets to deliver the
respective components used in the treatment process into the treatment volume 14.
[00125] The apparatus 100 can comprise a first drum inlet 17 to introduce solid particulate
material 30 into the treatment volume 14 of said drum 10. The solid particulate material 30
may or may not also be delivered in combination with treatment liquor, treatment agents
and/or any further additives from the same inlet 17.
[00126] The apparatus 100 can further comprise a second drum inlet 18 for receiving
treatment liquor into the treatment volume 14 of said drum 10. The second drum inlet 18 can
additionally be used to re-introduce solid particulate material into the treatment volume 14 of
said drum 10.
[00127] The upper portion of the drum 10 can thus comprise said first drum inlet 17 and said
second drum inlet 18. Each of said first drum inlet 17 and said second drum inlet 18 can
extend through a portion of the side wall 10a. Alternatively, the drum 10 can include an
opening 19 through which the one or more drum inlets project.
[00128] Within a lower portion of the drum 10 is the collecting volume 20. The collecting
volume 20 contains treatment liquor and solid particulate material that have previously
passed through treatment volume 14 following agitation with the substrate. The collecting
volume 20 can additionally comprise one or more inlets for the introduction of additional
treatment agents used in treatment process. In particular, the collecting volume 20 can
comprise one or more inlets to introduce gaseous treatment agents that can be used in the
treatment process.
[00129] A partition or screen 22 separates the collecting volume 20 from the treatment
volume 14. The partition 22 thus divides the internal volume of the drum 10 into two portions
respectively located at a first end and a second end. The partition 22 comprises a first side
which faces the treatment volume 14 and an opposed second side which faces the collecting
volume. The partition 22 can be in the form of a perforate or reticulate screen. Preferably,
the partition 22 is in the form of a mesh. The mesh may be extruded, orientated, expanded,
welded, etched, woven, knitted, or electroformed. Preferably the partition 22 is generally
planar. Furthermore, the partition is typically arranged to be substantially perpendicular to
the axis of rotation of the drum 10.
[00130] The partition 22 comprises a material that is sufficiently strong to withstand or
support the combined weight of animal skin substrates loaded into the treatment volume 14
of the drum 10. The treatment volume 14 can contain animal skin substrates with a
combined weight of anywhere between 50kg and 50,000kg. In addition, the partition 22
preferably comprises materials that exhibit some resistance to corrosion and particularly
comprises materials that exhibit resistance to the corroding effects of any chemicals or
additives present in the treatment liquor. Thus, the partition 22 can comprise corrosion
resistant metals, corrosion resistant metal alloys, plastics, fibrous, fibreglass, composites or
polymeric materials. Other flexible/ductile materials can also be used. Furthermore, the
partition 22 may be coated or uncoated.
[00131] The partition 22 may thus comprise metals and metal alloys including, but not
limited to, steel, aluminium, brass, copper, titanium and tungsten. In preferred embodiments
the partition 22 comprises stainless steel.
[00132] The partition 22 may thus comprise composites including, but not limited to, carbon,
boron or glass fibre filled polyester or polycarbonate.
[00133] The partition 22 may thus comprise plastic materials including, but not limited to,
polypropylene, polyethylene, polycarbonate, nylon, polyvinylchloride, high-density
polyethylene or polytetrafluoroethylene.
[00134] The partition 22 can comprise various combinations of the above-noted materials.
For example, the partition 22 can comprise plastic materials reinforced with a suitable metal
or metal alloy.
[00135] Where the partition 22 is in the form of a mesh, suitable meshes include, but are not
limited to, aramid, polycarbonate, polyester or polyacrylic polymer meshes.
[00136] As noted above, the partition 22 thus comprises a plurality of holes or apertures.
The apertures are dimensioned such that treatment liquor and the solid particulate material
can flow freely through the partition 22. However, the size of the apertures is such that the
animal skin substrates cannot pass through the partition 22. The partition 22 is therefore
arranged so that the animal skin substrates residing in the treatment volume 14 are
prevented from entering the collecting volume 20. The skilled person will however
understand that, depending on the size of the holes in the partition 22, orientations of the
animal skin substrate during rotation of the drum 10 may be possible whereby a minor part
such as an edge or periphery of a substrate temporarily projects into a portion of the space
defined by the collecting volume 20. However, the temporary transgression of a minor part of
a given animal skin substrate beyond the partition 22 into the collecting volume 20 has no
adverse impact on the performance of the apparatus 100 and the scope of the term
"prevented from entering the collecting volume 20" is thus intended to encompass such a
transitory occurrence.
[00137] The partition 22 can comprise apertures wherein said apertures have a maximum
dimension of about 125mm, 100mm, 75mm, 50mm, 35mm, 26mm, 25mm, 10mm, 5mm or
about 2mm. Said apertures can have a maximum dimension of from about 2 to 100mm, from
about 2 to 75mm, from about 2 to 50mm, from about 2 to about 35mm, from about 2 to
26mm, from about 2 to 25mm or from about 2 to about 10mm. The partition 22 can comprise
apertures having a maximum dimension of from about 2 to about 10mm, in particular about 4
to about 10mm, or said apertures can have a maximum dimension of from about 5 to about
8mm, or said apertures can have a maximum dimension from about 6 to about 10mm or the
partition 22 can comprise apertures having a maximum dimension of from about 26mm to
about 125mm.
[00138] Preferably, the solid particles employed in the invention have an average particle
diameter of from 1mm to 100 mm. The solid particles can have an average particle diameter
of from 1 to 50mm or 1 to 25mm or 1 to 15mm or 1 to 10mm or from 2.0 to 8.0mm, or the
solid particles can have a diameter of from 4.0 to 7.0mm or from 5.0 to 7.0mm, or the solid
particles can have an average particle diameter of from or 1.0 to 6.0mm, or from 1.0 to 5.0
mm or from 2.5 to 4.5mm. The effective average diameter can also be calculated from the
average volume of a particle by simply assuming the particle is a sphere. The average is
preferably a number average. The average is preferably performed on at least 10, more
preferably at least 100 particles and especially at least 1000 particles.
[00139] The solid particles can have a length of from 1mm to 100 mm, or from 1 to 50mm or
1 to 25mm, or from 1 to 15mm or from 1 to 10mm, or from 2.0 to 8.0mm, or from 4.0 to
7.0mm, or from 5.0 to 7.0mm. In other embodiments the solid particles can have a length of
from 1.0 to 6.0 mm, or from 1.0 to 5.0mm or from 2.5 to 4.5mm. The length can be defined
as the maximum 2 dimensional length of each 3 dimensional solid particle. The average is
preferably a number average. The average is preferably performed on at least 10, more
preferably at least 100 particles and especially at least 1000 particles.
[00140] The apparatus 100 further comprises a storage vessel 40 to retain the solid
particulate material 30 before delivery to the drum 10. The storage vessel 40 can be in the
form of a hopper. The apparatus 100 additionally includes a dispenser comprising a delivery
tube 17A connected to the storage vessel 40 to allow transport of solid particulate material
30 to the first drum inlet 17 for introduction to the treatment volume 14. Furthermore, storage
vessel 40 can include one or more valves or gates to control the entry of solid particulate
material 30 to delivery tube 17A thereby regulating the flow of solid particulate material 30 to
the drum 10. The storage vessel 40 can further comprise one or more inlets or outlets which
communicate with blowing and/or sucking devices to facilitate the flow of solid particulate
material to the delivery tube 17A.
[00141] The one or more valves or gates of the storage vessel 40 can further be used to
segregate the solid particulate material. Segregated solid particulate material can then be
cleaned, washed and rinsed in the storage vessel 40. Preferably, said storage vessel 40
additionally comprises one or more inlets for the introduction of cleaning agents to clean the
solid particulate material. Furthermore, said storage vessel 40 can comprise one or more
inlets to introduce gases cleaning agents for cleaning the solid particulate material.
[00142] Storage vessel 40 may be arranged above the inlet 17 of the drum 10 enabling the
solid particulate material 30 to pass along delivery tube 17A under the influence of gravity
into the drum 10. Other configurations are however possible whereby the storage vessel 40
is located at a position below the inlet 17 and additional pumping means are provided to
transport solid particulate material 30 from the storage vessel 40 into the drum 10.
[00143] The treatment apparatus 100 further comprises a conduit 26 for conveying
treatment liquor and/or the solid particulate material out of the drum 10 from the collecting
volume 20. In addition, the collecting volume 20 may also contain small quantities of matter
displaced from the animal skin substrate following agitation of the substrate in the treatment
volume 14. Matter displaced from the animal skin substrate will of course only enter the
collecting volume 20 if it is small enough to pass through the holes in the partition 22. The
conduit 26 has an inlet disposed proximate the lowermost part of the collecting volume and
forms a first portion of a circulation path (external to the drum) for conveying solid particles
and/or treatment liquor from the collecting volume 20 to the treatment volume 14. A portion
of the conduit 26 extends from the interior to the exterior of the drum 10 and has an axis
which is coincident with the axis of rotation of the drum 10. The conduit 26 can extend into
the collecting volume 20 and has an inlet 26A which opens into a lower region 20I of the
collecting volume 20 below the treatment liquor level (L) and proximate a lowermost region
of the side wall 10a. In some embodiments more than one of such conduits 26 can be
provided for independently conveying solid particulate material, treatment liquor or for
conveying solid particulate material and treatment liquor.
[00144] As noted above, the apparatus 100 includes a circulation path external to the drum
for conveying said solid particles from the collecting volume to the treatment volume. The
apparatus 100 additionally comprises a pumping device 50 to pump treatment liquor and/or
the solid particulate material from the collecting volume 20 along a portion of the circulation
path. Preferably, the pumping device 50 is arranged in the circulation path. Furthermore, the
pumping device 50 can be located downstream, preferably immediately downstream, of the
collecting volume 20. The pumping device 50 can be located at or proximate the lower end
wall portion 10b of the drum 10. Or the pumping device 50 can be located within the
collecting volume 20 of the drum 10.
[00145] Solid particulate material and/or treatment liquor can be conveyed from the
collecting volume 20 via conduit 26 to be received by a processing system 60. The
processing system 60 can comprise one or more compartments or units adapted to perform
various operations on the treatment liquor and/or solid particulate material received from the
drum 10. Solid particulate material and treatment liquor can pass into the processing system
60 through an entry port 62.
[00146] The processing system 60 is configured to separate the solid particulate material
from the treatment liquor received from the collecting volume 20. The processing system 60
may therefore comprise a separator including one or more filters or valves effective to
separate treatment liquor or at least a portion of the treatment liquor from the solid
particulate material. Furthermore, the processing system can comprise a device for
removing residual treatment liquor and deposits generated as a result of the treatment
process from said solid particles. The deposits can include any matter derived from the
animal skin substrates. In particular the processing system 60 can include one or more
blowing and/or sucking devices to enable removal of residual treatment liquor and/or
deposits from the solid particles. Furthermore, the processing system 60 can include a
device to carry out one or more washing or rinsing stages. The processing system 60 can
additionally comprise one or more inlets for the introduction of cleaning agents to enable
cleaning of the solid particulate material. Following the separation of treatment liquor from
the solid particulate material and/or following removal of residual treatment liquor and
deposits, the solid particulate material can be conveyed to the storage vessel 40 from an
outlet 69A of the processing system via a conduit 69. The conduit 69 comprises an end 69A
located at or proximate to an opening into storage vessel 40.
[00147] In addition, the processing system 60 can be configured to extract any waste
materials and effluent generated as a result of the treatment process. Waste material can
thus include any unwanted solids such as soil and particulate deposits displaced from the
surface of the animal substrate. The processing system 60 can thus comprise one or more
outlets for discharging treatment liquor and/or unwanted matter produced during the
treatment process. Treatment liquor pumped from the collecting volume 20, which may
further include said soil and particulate deposits entrained therein, can be subject to one or
more filtering operations. The processing system 60 can thus include one or more fine filters
for removing soil, particulate deposits along with any residual treatment agents. The filtering
operation can be conducted after the solid particles have been separated from the treatment
liquor. Following the filtering step, unwanted solids can be removed from the processing
system through a first outlet port 64 and first drain 65. The processing system 60 can
additionally comprise a second outlet port 66 and second drain 67 to remove liquid effluent
produced from the treatment process.
[00148] The processing system 60 can be adapted to recycle all of the treatment liquor or a
portion of the treatment liquor received from the collecting volume 20. Treatment liquor may
be recycled following the above-mentioned filtering operations to remove effluent and/or
unwanted solids. Recycled treatment liquor can be delivered to the treatment volume 14 of
the drum 10 via a conduit 18A extending from an outlet 72 of the processing system 60.
Treatment liquor enters the treatment volume 14 through second drum inlet 18. Thus in
some embodiments, there is provided a circulation path for treatment liquor extending from
the collecting volume 20 to the treatment volume 14 via the processing system 60.
Alternatively, or in addition, fresh treatment liquor can be delivered from the processing
system 60 to the treatment volume 14 of the drum 10 via conduit 18A. The recycled and/or
fresh treatment liquor can comprise water or water in combination with one or more
treatment agents. The apparatus 100 can comprise a plurality of outlets from the processing
system 60 and conduits each connected to a respective inlet that is in communication with
the treatment volume 14 of the drum 10. Such an arrangement can enable both recycled and
fresh treatment liquor to separately be introduced to the treatment volume 14 of the drum
10.The processing system 60 can comprise a liquid storage tank that can retain both fresh
and recycled treatment liquor for use in the treatment process. In such embodiments, the
processing system 60 can comprise one or more additional outlets to deliver treatment liquor
received from the collecting volume 20 to the liquid storage tank.
[00149] The apparatus 100 further provides a circulation path for the solid particulate
material that extends from the collecting volume 20 to the processing system 60.
Furthermore, the circulation path for the solid particulate material can extend from the
processing system 60 to the storage vessel 40. In some embodiments, solid particulate
material can be circulated and re-used in a single treatment process carried out by the
apparatus 100. Solid particulate material when circulated by the apparatus 100 can proceed
along the path indicated by the arrows labeled "A" as illustrated in Figure 1. The apparatus
100 can further include one or more blowing and/or sucking devices to facilitate conveyance
of the solid particles along the circulation path(s).
[00150] Alternatively, the apparatus 100 can provide a different circulation path for the solid
particulate material. In such embodiments, solid particulate material can proceed from the
collecting volume 20 to the processing system 60 via conduit 26 and then return to the
treatment volume 14 via the conduit designated 18A and drum inlet 18. In such
embodiments, conduit 18A extending from the outlet 72 of the processing system 60
conveys solid particles to the treatment volume 14 of the drum via drum inlet 18. In these
embodiments, a further inlet can be provided exclusively for the introduction of treatment
liquor. Alternatively, conduit 18A extending from the outlet 72 of the processing system 60
can convey both solid particles and treatment liquor to the treatment volume 14 of the drum
via drum inlet 18. In these embodiments, drum inlet 18 can convey solid particles and/or
treatment liquor for re-use in the treatment process performed in the drum 10 whereas drum
inlet 17 can provide the first introduction of solid particles and/or treatment liquor into the
drum 10.
[00151] The drum 10 can additionally comprise a closure 23. The closure 23 is moveable
between a closed position and an open position. In the closed position the closure 23 retains
fluids (i.e. the treatment liquor), animal skin substrate(s) and solid particles in the treatment
volume 14. Thus when the closure 23 is moved to a closed position, solid particles and
treatment liquor are prevented from entering the collection volume 20 and proceeding along
the above-noted circulation path. When the closure is move to an open position, solid
particles and treatment liquor can again pass freely through the partition 22 and proceed
through the collection volume 20 and enter the circulation path. The apparatus 100 may
comprise an electronic controller configured to move the closure 23 between open and
closed positions. The closure 23 can be located such that when it is moved to the closed
position it is brought directly in front of or in contact with the first side of the partition 22.
Alternatively, the closure 23 can be located such that when it is moved to the closed position
it is brought directly behind or in contact with the opposed second side of the partition 22.
The closure 23 can be in the form of a hingedly mounted or slidably mounted door or flap.
The closure 23 can comprise a diaphragm.
[00152] Advantageously, the provision of the closure 23 further enables the treatment
process to be carried out using only low levels of fluid. Thus, prior to conducting a treatment
cycle or a phase in the treatment cycle using the apparatus 100 of the invention, the closure
23 can be moved to a closed position. The animal skin substrates can be agitated in the
treatment volume with solid particles together with any fluids or treatment liquor present in
the drum with the closure 23 retained in the closed position. Typically agitation will be
performed for a predetermined period sufficient to complete a phase in the treatment cycle of
the animal skin substrate(s). When the predetermined period has elapsed, the closure can
be moved to the open position permitting free passage of solid particles and treatment liquor
through the partition 22 to the collection volume 20 prior to entering the circulation path. Use
of the embodiments comprising the closure 23 described above, ensures a constant
circulation of treatment liquor throughout the apparatus 100 is not necessary thus facilitating
effective treatment of the substrates with minimal liquor.Additional treatment liquor can be
introduced to the treatment volume after agitation of animal skin substrates and solid
particles with the closure 23 in a closed position. The addition of supplementary treatment
liquor can facilitate the circulation of solid particles from the collection volume 20 along the
above-noted circulation path(s).
[00153] Alternatively, the drum 10 can comprise a closure 23B (not shown in the figures)
moveable between a closed position and an open position whereby in the closed position
the closure 23B is configured to prevent solid particles from passing into the collecting
volume 20 from the treatment volume 14 whilst permitting the passage of fluids into the
collecting volume 20 from the treatment volume. Thus when the closure 23B is moved to a
closed position, solid particles are prevented from entering the collecting volume 20 and
proceeding along the above-noted circulation path yet treatment liquor can still be circulated
along the circulation path. When the closure 23B is moved to an open position, solid
particles and treatment liquor can again pass freely through the partition 22 and proceed
through the collection volume 20 and enter the circulation path. As for the closure 23 noted
above, the apparatus 100 may comprise an electronic controller configured to move the
closure 23B between open and closed positions. Furthermore, closure 23B can be located
such that when it is moved to the closed position it is brought directly in front of or in contact
with the first side of the partition 22. Alternatively, the closure 23B can be located such that
when it is moved to the closed position it is brought directly behind or in contact with the
opposed second side of the partition 22. The closure 23B can comprise a plurality of
apertures. The apertures of the closure 23B are smaller than the maximum dimension of the
solid particles to prevent their passage therethrough when the closure 23B is moved to the
closed position. Said apertures of the closure 23B can have a maximum dimension less than
1mm. The closure 23B can be in the form of hingedly mounted or slidably mounted member
with apertures formed therein. The closure 23B can be a perforate or reticulate screen or
can in the form of a mesh.
[00154] Advantageously, the use of the closure 23B in the apparatus 100 can limit the
quantity of solid particles accumulating in the collecting volume 20 reducing the possibility of
blocking the circulation path. Furthermore, closure 23B can enable the use of lower flow
rates providing energy savings and improvements in efficiency. During operation of the
treatment cycle a user can conveniently switch the position of the closure 23B between open
and closed positions as desired. For example, if the flow rate of solid particles through the
apparatus 100 and into the collecting volume 20 is too high, the flow of solid particles can
temporarily be arrested by moving the closure 23B into a closed position. In other
embodiments the closure 23B can be moved from an open position to a closed position or
from a closed position to an open position after a predetermined period in the treatment
cycle has elapsed.
[00155] The treatment process utilizing the method of the present invention can consist of a
"treatment cycle". As used herein, the term "treatment cycle" refers to the total duration
necessary to complete the desired treatment of the animal skin substrate and may comprise
one or more phases or stages. For example, a first portion of the treatment liquor which may
comprise water can be added to the animal skin substrate before the addition of the solid
particulate material. The animal skin substrate can be agitated with the treatment liquor
alone in the drum of the apparatus prior to agitation with the treatment liquor in combination
with the solid particulate material as a first phase of the treatment process. A second portion
of the treatment liquor which may comprise one or more treatment agents and/or further
additives can be added at a different time point in the treatment cycle. A series of treatment
phases or stages can thus be conducted over the duration of the treatment cycle wherein the
treatment liquor can be kept constant or varied for each respective phase.
[00156] The solid particulate material can be retained throughout the treatment cycle as
portions of the treatment liquor are added as outlined above. Alternatively, the solid
particulate material can be replaced prior to the addition of a further portion of the treatment
formulation. This can be necessary to ensure that the animal skin substrate is not adversely
affected by interactions occurring between incompatible chemical moieties. For example,
chemical moieties which could potentially adhere to the solid particulate material following
the introduction of one portion of the treatment liquor may not be compatible with chemical
moieties present in a subsequent portion of the treatment liquor thus necessitating
replacement of the solid particulate material before continuing the treatment cycle.
[00157] Each phase of the treatment cycle can comprise one or more agitation steps
wherein the animal substrates are agitated with the solid particulate material and treatment
liquor. After a given agitation step, the solid particulate material can be transferred from the
treatment volume to the collecting volume and circulated back to the treatment volume along
a circulation path in the manner described above. In this way, a further or subsequent
agitation step can be carried out with the same solid particulate material.
[00158] The duration of the treatment cycle can be any period from 1 minute to 00 hours
and in other embodiments the duration of the treatment cycle can be from 1 minute to 48
hours. Where the treatment cycle comprises more than one phase, each respective phase
of the treatment cycle can be any period of 30 seconds or greater or 1 minute or greater
wherein the sum of the respective phases comprises the total duration of the treatment
cycle. Each respective phase of the treatment cycle can be a period of from 30 seconds to
10 hours.
[00159] The apparatus and method of the invention facilitates a considerable reduction in
the duration of a typical treatment cycle as the presence of the solid particulate material
enhances the effect or degree of mechanical action performed on the animal substrate.
Furthermore, as the apparatus and method of the invention enables a reduction in the
quantity of water or liquor needed in the drum, the effective concentration of chemicals
dissolved in the treatment liquor is increased thereby resulting in faster mass transfer to the
animal skin substrate(s) leading to a reduction in the duration of the treatment cycle time.
Thus the duration of each phase of the process can be reduced leading to a typical reduction
of 20 to 50% of the total duration of the treatment cycle when compared to the methods
employed in the prior art.
[00160] Optionally, the mechanical action performed on the animal skin substrate by virtue
of agitation with the solid particulate material is never sufficient to break up the animal
substrate. Optionally, the solid particulate material does not penetrate the surface of the
animal substrate.
[00161] The solid particulate material of the invention can thus be re-used one or more
times for treatment of the animal substrates in a single treatment cycle or in subsequent
treatment cycles. In this context, a single "use" of the solid particulate material equates to a
single agitation step as performed in the treatment volume with the animal skin substrates.
Preferably, the solid particulate material can be re-used at least two, three, four, five or more
times, such as 10, 20, 50 or 100 or more times. The solid particulate material is typically not
reused more than 10,000 or more than 1,000 times.
[00162] The solid particulate material can be subject to a cleaning operation. Intermittent
cleaning of the solid particulate material is often desirable when the solid particulate material
is re-used. Preferably, the cleaning of the solid particulate material is conducted within the
processing system 60. Alternatively, the cleaning of the solid particulate material can be
carried out within the drum 10 or within the storage vessel 40. Cleaning can be helpful in
preventing unwanted contaminants from building up and/or in preventing treatment
components from degrading and then depositing on the animal substrate. The particle
cleaning step can be performed, for example, after every 10, after every 5 , after every 3 ,
after every 2 or after every 1 agitation step(s). The cleaning step can comprise washing the
solid particulate material with a cleaning formulation. The cleaning formulation can be a
liquid medium such as water, an organic solvent or a mixture thereof. Preferably, the
cleaning formulation can comprise at least 1wt%, preferably 10wt%, more preferably at least
30wt%, even more preferably at least 50wt%, especially at least 80wt% water, more
especially at least 90wt% water. The cleaning formulation can comprise one or more
cleaning agents to aid the removal of any contaminants. Suitable cleaning agents can
include surfactants, detergents, bleaching agents (e.g. sodium hypochlorite), oxidizing
agents (e.g. hydrogen peroxide), dye transfer agents, biocides, fungicides, builders, acids,
bases (e.g. sodium hydroxide and ammonium hydroxide), reducing agents and metal
chelating agents. In alternative embodiments gaseous cleaning agents can be used such as
ammonia and ozone. The solid particulate material can be cleaned at a temperature of from
0 to 40°C for energy economy but for even better cleaning performance temperatures of
from 4 1 to 100°C can be used. The cleaning times can generally be from 1 second to 10
hours, typically from 10 seconds to 1 hour and more typically from 30 seconds to 30
minutes. The cleaning formulation can be acidic, neutral or basic depending on the pH which
best provides for cleaning of the specific components circulated from the drum 10.
[00163] As noted above, the solid particulate material can be subjected to a cleaning
operation within the drum 10. In such embodiments, after an agitation step with treatment
liquor and solid particles has been completed, the treatment liquor can first be drained from
the drum 10 and then cleaning formulation introduced to the drum 10. The cleaning
formulation can comprise water and/or any of the cleaning agents described above.
Following the introduction of the cleaning formulation, the solid particles can be agitated
within the drum. After the cleaning operation has been completed, the solid particles can be
re-used for additional agitation and/or treatment steps. Conducting a cleaning operation in
this manner can be particularly advantageous for tanning processes which may include
tanning agents in the treatment liquor. Thus any unreacted tanning agent can be washed
from the solid particles and the animal skin substrates which enables an increase in the pH
and removal of surplus salt. The increase in pH provides improved conditions for conducting
subsequent processes such as retanning and/or dyeing treatments.
[00164] Alternatively, the solid particulate material can be removed from the apparatus 100
and cleaned before its re-use in an additional phase of the treatment process. The solid
particulate material can be replaced before commencing an additional phase in the
treatment process.
[00165] The apparatus 100 can include means to facilitate the easy removal of the solid
particulate material after the end of a phase in the treatment process or after completion of
the treatment process. The apparatus 100, and preferably the drum 10, can thus include a
vacuum, a blower, a magnet or other appropriate apparatus to facilitate solid particle
removal.
[00166] The apparatus 100 can further comprise one or more blowing and/or sucking
devices to promote conveyance of the solid particles along the circulation path(s).
[00167] The solid particulate material employed in the apparatus and process of the
invention can comprise a multiplicity of polymeric or non-polymeric particles. Most
preferably, the solid particulate material can comprise a multiplicity of polymeric particles.
Alternatively, the solid particulate material can comprise a mixture of polymeric particles and
non-polymeric particles. Alternatively, the solid particulate material can comprise a
multiplicity of non-polymeric particles. Thus the solid particulate material of the invention can
comprise exclusively polymeric particles, exclusively non-polymeric particles or mixtures of
polymeric and non-polymeric particles in any desired relative amounts. Throughout this
disclosure wherever a ratio is quoted with respect to polymeric and/or non-polymeric
particles this will be understood as a reference to the sum total of polymeric and/or nonpolymeric
particles that may constitute the solid particulate material.
[00168] The polymeric or non-polymeric particles are of such a shape and size as to allow
for good flowability and intimate contact with the animal skin substrate. A variety of shapes
of particles can be used, such as cylindrical, spherical, ellipsoidal, spheroidal or cuboid;
appropriate cross-sectional shapes can be employed including, for example, annular ring,
dog-bone and circular. Ellipsoidal, spheroidal or spherical solid particles are particularly
preferred. The particles can have smooth or irregular surface structures and can be of solid,
porous or hollow construction. Non-polymeric particles comprising naturally occurring
materials such as stone may have various shapes, dependent on their propensity to cleave
in a variety of different ways during manufacture. Most preferably, however, said particles
can comprise cylindrical, ellipsoidal, spheroidal or spherical beads.
[00169] The multiplicity of solid particles employed in the invention are preferably of such a
size as to have an average mass in the region of 1mg to 500g, more preferably from 1 mg to
100g, more preferably from 1mg to 1g and most preferably 5mg to 100mg.
[00170] The multiplicity of solid particles of the invention can be chemically modified to
include additional moieties. Thus the particles can be chemically modified to further include
one or more moieties selected from the group consisting of: enzymes, oxidizing agents,
catalysts, metals, reducing agents, chemical cross-linking agents and biocides.
[00171] The polymeric particles can comprise polyalkenes such as polyethylene and
polypropylene, polyamides, polyesters, polysiloxanes or polyurethanes. Furthermore, said
polymers can be linear, branched or crosslinked. Said polymeric particles can comprise
polyamide or polyester particles, particularly particles of nylon, polyethylene terephthalate or
polybutylene terephthalate, typically in the form of beads. Copolymers of the abovepolymeric
materials can also be employed for the purposes of the invention. The properties
of the polymeric materials can be tailored to specific requirements by the inclusion of
monomeric units which confer particular properties on the copolymer. Various nylon homoor
co-polymers can be used including, but not limited to, Nylon 6 and Nylon 6,6. The nylon
can comprise Nylon 6,6 copolymer, preferably having a molecular weight in the region of
from 5000 to 30000 Daltons, more preferably from 10000 to 20000 Daltons, most preferably
from 15000 to 16000 Daltons. The polyester can typically have a molecular weight
corresponding to an intrinsic viscosity measurement in the range of from 0.3 to 1.5 dl/g, as
measured by a solution technique such as ASTM D-4603. Said polymeric particles can
comprise synthetic or natural rubber.
[00172] The polymeric particles can have an average density of about 0.5 g/cm3 to about
3.5 g/cm3. Polymeric particles having an average density of 0.5 to 2.5g/cm 3 can be
particularly suitable. Polymeric particles having an average density of 0.5 to less than
1g/cm3 can be particularly suitable.
[00173] The polymeric or non-polymeric particles can be solid, porous or hollow.
[00174] The solid particulate material can comprise non-polymeric particles. In such
embodiments, the non-polymeric particles can comprise ceramic material, refractory
material, igneous, sedimentary or metamorphic minerals, composites, metal, glass or wood.
Suitable metals include, but are not limited to, zinc, titanium, chromium, manganese, iron,
cobalt, nickel, copper, tungsten, aluminium, tin, and alloys thereof (such as steel). Suitable
ceramics can include, but are not limited to, alumina, zirconia, tungsten carbide, silicon
carbide and silicon nitride.
[00175] The non-polymeric particles may have an average density of 0.5 to 20 g/cm3, more
preferably from 2 to 20g/cm 3, especially from 4 to 15g/cm3 and most especially from 4 to
10g/cm3.
[00176] In order to provide lubrication for the treatment system, the or each animal skin
substrate can be moistened. This can be achieved by wetting the substrates with water by
contact with mains or tap water for example. Wetting of the substrates within the apparatus
of the invention is however preferable. The wetting of the substrates can be carried out so as
to achieve a water to animal skin substrate ratio of between 1000:1 and 1:1000 w/w.
Typically, the ratio of water to animal skin substrate can be from 1:100 to 1:1w/w more
typically from 1:50 to 1:2w/w, especially typically from 1:40 to 1:2w/w, more especially
typically from 1:20 to 1:3w/w and most typically from 1:15 to 1:5w/w. The ratio of water to
animal skin substrate can be at least 1:40w/w, at least 1:30w/w, at least 1:20w/w or at least
1:15w/w. The ratio of water to animal skin substrate can be no more than 10:1w/w, no more
than 5:1 w/w, no more than 2:1w/w or no more than 1:1w/w.
[00177] It may be desirable that no further water is added to the animal skin substrate
other than that present in the animal skin substrate(s) as a result of prior treatment methods.
Thus, the treatment liquor can be formed by adding a "neat" treatment agent or combination
of "neat" treatment agents to the treatment volume 14 of the drum 10. In this context "neat"
preferably means only the active or efficacious component of the treatment agent is added
and is thus introduced to the treatment volume without further liquid diluents such as water,
organic liquids and the like. The treatment agent can be added to the treatment volume in
the form of a dry powder or alternatively as a liquid containing only the active component.
The liquid (especially water) already present in the prewetted or premoistened animal skin
substrate is therefore sufficient to form the treatment liquor "in situ" within the drum.
Advantageously, this approach can ensure the amount of liquid or water used is the
treatment process is even lower. Also, it has been found that this approach can lead to a
further improvement in the treatment in terms of uniformity, depth of penetration and in terms
of the percentage of treatment agents which are incorporated into the animal skin substrate.
In this way the resulting animal skin substrate after treatment is of a better quality (having
improved chemical, physical or aesthetic properties) and the amounts of treatment agents
remaining in the liquor after the treatment method is complete are even further reduced.
[00178] The weight ratio of animal skin substrate(s) : solid particulate material is preferably
from 10:1 to 1:10, more preferably from 5:1 to 1:5, preferably from 3:1 to 1:3, preferably from
2:1 to 1:2. Preferably, the weight of the animal skin substrate for this ratio is based on the
wet weight of the animal skin substrate. The wet weight of the animal skin substrate used
herein preferably refers to any latent fluid (typically water) present within the animal skin
substrate itself.
[00179] Preferably, throughout this invention the dry weight of a wet substrate is from 25 to
75wt% of the wet weight, typically about 50wt%. So for example, 2Kgs of wet animal skin
substrate comprises 1Kg of dry animal substrate.
[00180] The weight ratio of the animal skin substrate(s) : fluid (especially water) is
preferably from about 1:5 to about 100:1 , typically from about 1:2, typically from about 1:1,
and typically from about 2:1, typically from about 3:1 and typically from about 5:1 , typically
no more than about 40: 1, typically no more than about 30: 1, typically no more than about
20: 1, and typically no more than about 15 :1. Preferably the weight of the animal skin
substrate is based on the wet weight of the animal skin substrate.
[00181] The weight ratio of the dry animal skin substrate : fluid is preferably from 10:1 to
1:10, more preferably 7:1 to 1:7, even more preferably 4:1 to 1:4, yet more preferably 3:1 to
1:3 and most preferably 2 :1 to 1:2 by weight.
[00182] Preferably, the ratio of the treatment volume of the drum (in m3) : to the weight of
fluid in the drum (in metric tonnes) is from about 1:100 to about 100: 1.
[00183] Preferably, the ratio of the treatment volume of the drum (in m3) : to the weight of
fluid in the drum (in metric tonnes) is in order of increasing preference at least 1:4, 1:3, 1:2,
1:1 , 2:1 , 3:1, 4:1, 5:1 , 10:1, 20:1, 25:1 , 30:1 , 35:1, 40:1 , 45:1 , 50:1, 60:1 and 70:1.
[00184] The ratio of the treatment volume of the drum (in m3) : to the weight of fluid in the
drum (in metric tonnes) can be, in order of increasing preference, no more than about 75:1,
no more than 60: 1, no more than 50: 1, no more than 40: 1, no more than 30: 1, no more than
25: 1, no more than 20: 1 and no more than 15:1 .
[00185] The treatment liquor employed by the present invention can comprise a liquid
medium and preferably comprises water or water when combined with at least one treatment
agent and/or any further additives as detailed hereinbelow. The composition of the treatment
liquor may depend at any given time on the point which has been reached in the treatment
process. Thus, for example, at the start of the treatment process, the treatment liquor may
be water. At a later point in the treatment process the treatment liquor may include one or
more treatment agents and/or one or more further additives. Alternatively, one or more
treatment agents and/or one or more further additives may be added in combination with
water at the start of the treatment process. During the treatment process, the treatment
liquor may also include suspended soil and/or particulate deposits removed from the animal
substrate.
[00186] The treatment liquor can be aqueous. The treatment liquor can comprise at least
0.1 % w/w water or at least 1% w/w water or at least 5% w/w water or between 5% and
99.9% w/w water. The treatment liquor can comprise not more than 99.9% w/w water.
[00187] Treatment liquor can comprise water alone or it can comprise water and one or
more organic solvents. The organic solvents may be water-miscible. Preferred organic
solvents can be alcohols, glycols and amides. In certain embodiments, the treatment liquor
comprises at least 10wt%, more preferably at least 50wt%, especially at least 80wt%, more
especially at least 90wt% and most especially at least 95wt% of water. The treatment liquor
comprises preferably less than 10wt%, more preferably less than 10wt% organic solvents. In
some embodiments no organic solvents are present in the treatment liquor other than trace
amounts from impurities in other components of the treatment liquor.
[00188] The treatment process performed on the animal skin substrate can comprise a
cleaning step. The cleaning step can be performed prior to a chemical modification of the
substrate. Cleaning may be necessary to remove any unwanted materials adhered to the
exterior of the animal substrate. The treatment liquor used in the cleaning step can comprise
one or more enzymes. The treatment liquor can comprise proteolysis enzymes. In order to
enhance cleaning of the animal skin substrate, in particular in a cleaning step, the treatment
liquor can comprise one or more surfactants. Preferably, the treatment liquor can comprise
non-ionic surfactants.
[00189] The treatment process can comprise one or more additional steps to remove further
unwanted materials from the animal substrate. For example, the animal skin substrate can
be subject to liming and deliming. In such embodiments, the treatment liquor, at least for
such additional steps, can comprise reducing agents, bases, acids and/or neutralizing
agents.
[00190] The treatment liquor of the invention can comprise one or more components
effective to modify the animal skin substrate in some way and optionally impart certain
properties to the modified substrate. Thus the treatment liquor can contain ingredients which
perform a cleaning function and ingredients that elicit other effects such as chemical
modification of the substrate. The treatment liquor of the invention can comprise one or more
components selected from the group consisting of: solvents, surfactants, cross-linking
agents, metal complexes, corrosion inhibitors, complexing agents, biocides, builders,
catalysts, chelating agents, dispersants, perfumes, optical brightening agents, enzymes,
dyes, pigments, oils, waxes, waterproofing agents, flame retardants, stain repellants,
reducing agents, acids, bases, neutralizing agents, polymers, resins, oxidising agents and
bleaches.
[00191] Suitable surfactants for use in the treatment liquor can be selected from non-ionic
and/or anionic and/or cationic surfactants and/or ampholytic and/or zwitterionic and/or semipolar
nonionic surfactants.
[00192] Suitable builders can be included in the treatment liquor and these include, but are
not limited to, the alkali metal, ammonium and alkanolammonium salts of polyphosphates,
alkali metal silicates, alkaline earth and alkali metal carbonates, aluminosilicates,
polycarboxylate compounds, ether hydroxypolycarboxylates, copolymers of maleic
anhydride with ethylene or vinyl methyl ether, 1,3,5-trihydroxybenzene-2,4,6-trisulphonic
acid, and carboxymethyl-oxysuccinic acid, various alkali metal, ammonium and substituted
ammonium salts of polyacetic acids such as ethylenediamine tetraacetic acid and
nitrilotriacetic acid, as well as polycarboxylates such as mellitic acid, succinic acid,
oxydisuccinic acid, polymaleic acid, benzene ,3,5-tricarboxylic acid,
carboxymethyloxysuccinic acid and soluble salts thereof.
[00193] Optionally, the treatment liquor can also contain dispersants. Suitable watersoluble
organic materials are the homo- or co-polymeric acids or their salts, in which the
polycarboxylic acid may comprise at least two carboxyl radicals separated from each other
by not more than two carbon atoms.
[00194] Optionally, the treatment liquor can also contain perfumes. Suitable perfumes can
generally be multi-component organic chemical formulations which can contain alcohols,
ketones, aldehydes, esters, ethers and nitrile alkenes, and mixtures thereof. Commercially
available compounds offering sufficient substantivity to provide residual fragrance include
Galaxolide (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta(g)-2-benzopyran),
Lyral (3- and 4-(4-hydroxy-4-methyl-pentyl) cyclohexene-1-carboxaldehyde and Ambroxan
((3aR,5aS,9aS,9bR)-3a,6,6,9a-tetramethyl-2,4, 5,5a, 7,8,9, 9b-octahydro-1 H-benzo[e][1]
benzofuran). One example of a commercially available fully formulated perfume is Amour
Japonais supplied by Symrise® AG.
[00195] The treatment liquor can include an optical brightening agent. Suitable optical
brighteners which can be included in the treatment liquor fall into several organic chemical
classes, of which the most popular are stilbene derivatives, whilst other suitable classes
include benzoxazoles, benzimidazoles, 1,3-diphenyl-2-pyrazolines, coumarins, 1,3,5-triazin-
2-yls and naphthalimides. Examples of such compounds can include, but are not limited to,
4,4'-bis[[6-anilino-4(methylamino)-1,3,5-triazin-2-yl]amino]stilbene-2,2'-disulphonic acid, 4,4'-
bis[[6-anilino-4-[(2-hydroxyethyl)methylamino]-1,3,5-triazin-2-yl]amino]stilbene-2,2'-
disulphonic acid, disodium salt, 4,4'-Bis[[2-anilino-4-[bis(2-hydroxyethyl)amino]-1,3,5-triazin-
6-yl]amino]stilbene-2,2'-disulphonic acid, disodium salt, 4,4'-bis[(4,6-dianilino-1 ,3,5-triazin-2-
yl)amino]stilbene-2,2'-disulphonic acid, disodium salt, 7-diethylamino-4-methylcoumarin,
4,4'-Bis[(2-anilino-4-morpholino-1,3,5-triazin-6-yl)amino]-2,2'-stilbenedisulphonic acid,
disodium salt, and 2,5-bis(benzoxazol-2-yl)thiophene.
[00196] The treatment process of the invention can comprise a step wherein the animal skin
substrate is agitated with a treatment liquor comprising one or more oils. The inclusion of
one or more oils in the treatment liquor can impart specific properties to the substrate. The
treatment liquor can comprise oils with at least one sulphur moiety such as sulphated and/or
sulphited oils to provide softness and flexibility to the animal substrate. In other
embodiments, oils can be included to provide anti-static control, reduce friction and/or to
improve lubrication.
[00197] Suitable acids which can be contained in the treatment liquor include, but are not
limited to, sulphuric acid, formic acid and ammonium salts (e.g. ammonium sulphate and
ammonium chloride). Suitable bases can include, but are not limited to, calcium hydroxide
and sodium hydroxide. Suitable neutralizing agents include, but are not limited to, sodium
carbonate and sodium bicarbonate.
[00198] Enzymes that can be used in the treatment liquor can include, but are not limited to,
hemicellulases, peroxidases, proteases, carbonic anhydrases, cellulases, xylanases,
lipases, phospholipases, esterases, cutinases, pectinases, keratanases, reductases,
oxidases, phenoloxidases, lipoxygenases, ligninases, pullulanases, tannases,
pentosanases, malanases, [beta]-glucanases, arabinosidases, hyaluronidase,
chondroitinase, laccase, amylases and mixtures thereof.
[00199] Dyes that may be used in the treatment liquor can include, but are not limited to,
anionic, cationic, acidic, basic, amphoteric, reactive, direct, chrome-mordant, pre-metallised
and sulphur dyes.
[00200] The treatment liquor can include one or more bleaches and/or oxidizing agents.
Examples of such bleaches and/or oxidizing agents can include, but are not limited to,
ozone, peroxygen compounds, including hydrogen peroxide, sodium hypochlorite, inorganic
peroxy salts, such as perborate, percarbonate, perphosphate, persilicate, and mono
persulphate salts (e.g. sodium perborate tetrahydrate and sodium percarbonate), and
organic peroxy acids such as peracetic acid, monoperoxyphthalic acid,
diperoxydodecanedioic acid, N,N'-terephthaloyl-di(6-aminoperoxycaproic acid), N,N'-
phthaloylaminoperoxycaproic acid and amidoperoxyacid. The bleaches and/or oxidizing
agents can be activated by a chemical activation agent. Activating agents can include, but
are not limited to, carboxylic acid esters such as tetraacetylethylenediamine and sodium
nonanoyloxybenzene sulphonate. Alternatively, the bleach compounds and/or oxidizing
agents can be activated by heating the treatment liquor.
[00201] Preferably, the treatment process of the invention includes one or more chemical
modification steps in order to colour the substrate. Thus, the treatment liquor can include at
least one colourant. The colourant can be selected from, for example, one or more dyes,
pigments, optical brighteners or mixtures thereof.
[00202] The colourant can be one or more dyes selected from anionic, cationic, acidic,
basic, amphoteric, reactive, direct, chrome-mordant, pre-metallised and sulphur dyes.
[00203] The solid particulate material can be substantially uncoated with one, several or all
components of the treatment liquor (excluding of course water). In particular, prior to at least
a first agitation step it is preferred that the solid particulate material is not coated with a
colourant (e.g. a dye or a pigment). The treatment liquor and the solid particulate material
can be premixed prior to the agitation step but this is preferably under conditions which do
not promote or cause the colourant to coat the particles of the solid particulate material. So
for example, the colourant can be a dye which is soluble in the treatment liquor, e.g. having
a solubility of greater than 1 g per litre, more preferably greater than 2g per litre and
especially greater than 5g per litre of the treatment liquor, and/or additional organic solvents
can be added to the water in the treatment liquor to promote solubility of the dye, and/or the
solid particulate material can be chosen which specifically has no affinity with the dye.
Suitable organic solvents can include water-miscible alcohols, glycols, amides and the like.
When the colourant is insoluble or only partially soluble in the treatment liquor it is preferred
that the colourant is dispersed with one or more dispersants. These can be cationic, anionic
or non-ionic dispersants. Coating of the solid particulate material may be prevented or
inhibited by having dispersants of the same type which stabilize both the solid particulate
material and the colourant during the agitation step. For example both the colourant and the
solid particulate material can be dispersed with an anionic dispersant, both can be dispersed
with a cationic dispersant or both can be dispersed with a non-ionic dispersant. When
dispersing the colourant it is preferably a pigment, an insoluble dye or a slightly soluble dye
(<1g litre) dye. When the colourant is dispersed or dissolved in the treatment liquor in the
presence of the particulate solid this is preferably done below 30°C, more preferably below
25°C. Using lower temperatures tends to reduce the possibility for coating the solid
particulate material.
[00204] The colourant can be dispersed or dissolved in the treatment liquor. The colourant
can be dispersed or dissolved in the treatment liquor in the absence of the solid particulate
material. This can help to prevent any possibility that the colourant pre-coats the solid
particulate material. The solid particulate material can then be added prior to or during
agitation. Alternatively, the colourant can be dispersed or dissolved in an aqueous liquid
medium (again in the absence of the solid particulate material) and then added to the
treatment liquor.
[00205] A mixture of the treatment liquor containing a colourant and the solid particulate
material can be such that substantially no coating of the solid particulate material results and
the colourant does not penetrate into the solid particulate material. This can be determined
by: i . adding 100g of solid particulate material to 100g of water containing 2wt% of colourant;
ii. stirring the mixture for 1 hour at 25°C; iii. removing the solid particulate material from the
water by means of filtration; iv. measuring the amount of colourant remaining in the water
(e.g. by colourimetic, UV, refractive index or gravimetric analysis); and v. calculating the
amount of colourant which has not coated or penetrated the solid particulate material.
Preferably, this value should mean that greater than 90wt%, more preferably greater than
95wt%, especially greater than 98wt% and more especially greater than 99wt% of the
colourant remains in the water. Preferably, the water is at pH 7 .
[00206] The treatment liquor can comprise a colourant and the treatment process can
comprise applying the colourant to the animal skin substrate wherein at least some of the
colourant so applied originates from the treatment liquor. Typically, at least some, more
typically essentially all of the colourant so applied was, prior to application, physically
separate from the solid particulate material. Preferably, at least 50wt%, more preferably at
least 70wt%, especially at least 90wt%, more especially at least 99wt% and most especially
essentially all the colourant which is applied to the animal skin substrate originates from the
treatment liquor (and not from the surface or interior of the solid particulate material).
Preferably, during the method which comprises applying a colourant to the animal skin
substrate there is no measurable net loss of colourant from the solid particulate material.
This shows that essentially all of the colour applied to the animal skin substrate originates
from the treatment liquor. Typically, the amount of colourant in or coating the particulate solid
will remain constant or may just slightly rise during the agitation process.
[00207] The treatment liquor can have a basic (>7), an acidic (<7) or neutral (7) pH. It can
be desirable that the pH of the treatment liquor in certain treatment steps or stages is acidic.
The acidic pH is typically less than 6.9, more typically less than 6.5, even more typically less
than 6 and most typically less than 5.5. The acidic pH is typically no less than 1, more
typically no less than 2 and most typically no less than 3 . The pH or the treatment liquor can
differ at different times, points or stages in the treatment process according to the invention.
Preferably, the treatment liquor has the above typical pH value for at least some time during
the agitation.
[00208] Before or after said agitating the animal skin substrate with a treatment liquor and a
solid particulate material, the methods of the present invention can include any one or more
of the following steps used in the production of leather including: curing, fat liquoring,
scudding, preserving, fleshing, splitting, soaking, liming, deliming, reliming, unhairing, bating,
degreasing, frizzing, bleaching, pickling, depickling, pretanning, tanning, retanning, tawing,
crusting, coating and dyeing and finishing.
[00209] Preferably, said treatment process is a tannery process and said treatment liquor
comprises at least one treatment agent selected from tanning agents, re-tanning agents and
tannery process agents.
[00210] The apparatus and method of the invention can facilitate a considerably higher level
of incorporation of treatment agents such as tanning agents into the animal skin substrate
thereby reducing the amount of chemicals wasted to effluent. The reduction of chemicals lost
to effluent may be 10-50% w/w of the chemicals typically used in the methods employed in
the prior art.
[00211] Preferably, said tannery process is selected from one or more of cleaning, curing,
beamhouse treatments, tanning, re-tanning, fat liquoring, enzyme treatment, dyeing and dye
fixing..
[00212] Preferably, the treatment process of the invention is a process used in the
production of leather and can include one or more of: curing, beamhouse treatments, fat
liquoring, pretanning, tanning, retanning, tawing, crusting and dyeing.
[00213] As used herein beamhouse treatments can include soaking, liming, deliming,
reliming, unhairing, fleshing, bating, degreasing, scudding, bating, pickling and depickling.
[00214] Preferably, the tanning agent and/or tannery processing agents can be selected to
chemically modify the animal substrate, such as, for example, by linking and locking collagen
protein strands of the animal skin substrate together. The three dimensional protein
structure of the animal skin substrate can be modified.
[00215] Advantageously, the apparatus and method of the invention can facilitate a deeper
and more uniform penetration of tanning agents into the animal skin substrate thereby
improving the preservation of the substrate compared to the methods used in the prior art.
[00216] Preferably, the process of the invention comprises applying the tanning agent or
tannery process agent to the animal skin substrate wherein at least some of the tanning
agent or tannery process agent so applied originates from the treatment liquor. More
preferably substantially all of the tanning agent or tannery process agent so applied
originates from the treatment liquor.
[00217] Preferably, the tanning or re-tanning agent can be selected from synthetic tanning
agents, vegetable tanning or vegetable re-tanning agents and mineral tanning agents such
as chromium III salts or salts and complexes containing iron, zirconium, aluminium and
titanium. In some embodiments all the tanning agents used are substantially free from
chromium containing compounds.
[00218] The tanning agents can be synthetic tanning agents. Suitable synthetic tanning
agents include, but are not limited to amino resins, polyacrylates, fluoro and/or silicone
polymers and formaldehyde condensation polymers based on phenol, urea, melamine,
naphthalene, sulphone, cresol, bisphenol A, naphthol and/or biphenyl ether.
[00219] The tanning agents can be vegetable tanning agents. Vegetable tanning agents
comprise tannins which are typically polyphenols. Vegetable tanning agents can be obtained
from plant leaves, roots and especially tree barks. Examples of vegetable tanning agents
can include the extracts of the tree barks from chestnut, oak, redoul, tanoak, hemlock,
quebracho, mangrove, wattle acacia; and myrobalan.
[00220] The tanning agents can be mineral tanning agents. Particularly suitable mineral
tanning agents comprise chromium compounds, especially chromium salts and complexes.
The chromium is preferably in a chromium (III) oxidation state. A preferred chromium (III)
tanning agent is chromium (III) sulphate.
[00221] Other tanning agents can include aldehydes (glyoxal, glutaraldehyde and
formaldehyde), phosphonium salts, metal compounds other than chromium (e.g. iron,
titanium, zirconium and alumunium compounds). The treatment liquor, especially for
tanning, can be acidic, neutral or basic. Vegetable and chromium tanning agents are
preferably used with acidic treatment formulations. The treatment liquor can preferably
comprise sulfuric, hydrochloric, formic or oxalic acid in embodiments where acidic
formulations are to be used.
[00222] Optionally, water in the treatment liquor has been softened or demineralized.
[00223] The treatment liquor can include one or more waterproofing agents. Examples of
suitable waterproofing agents are hydrophobic silicones. The treatment liquor can include
one or more flame retardants. Suitable flame retardants can include, but are not limited to,
titanium hexfluoride or zirconium hexafluoride. The treatment liquor can include one or more
stain repellants. Suitable stain repellants can include, but are not limited to, polysulphones,
waxes, salts, silicone polymers and polytetrafluoroethylene (PTFE).
[00224] As the process of the invention can be used with significantly less water than
methods of the prior art, the quantity of chemicals or chemical loading in the treatment liquor
can be reduced.
[00225] One or more phases of the treatment process of the invention can be performed at
a temperature of from 0 to 100 °C. Furthermore, the treatment process can include one or
more heating or cooling steps. Thus the temperature may be raised or lowered between the
values of 0 and 100 °C at one or more points throughout the treatment cycle. One or more
phases of the method can be performed at a temperature of from 0 to 60°C such as from 20
to 60 °C, or at a temperature of from 30 to 50 or 60 °C. As the method of the invention can
lead to a reduction in the duration of the treatment cycle, it is possible for the treatment
process to be carried out effectively at lower temperatures. For example, in one or more
phases of the treatment cycle the treatment process can effectively be performed at ambient
temperature as opposed to higher temperatures which are generally required in the
processes of the prior art. Also, because smaller amounts of treatment liquor can be used
the amount of energy required to obtain these temperatures can be substantially reduced.
[00226] An exemplary treatment process utilizing the apparatus 100 of the invention can
now be outlined. First, the animal skin substrate is placed within the treatment volume 14 of
the drum 10 via access means 12. After the access means 12 is closed, treatment liquor
together with any treatment agents are introduced to the treatment volume 14 through drum
inlet 18 (or alternatively through drum inlet 17). In addition, solid particulate material 30
residing in storage vessel 40 is introduced to the treatment volume through drum inlet 17.
Treatment liquor and solid particulate material fills the treatment volume 14 of the drum but
allows for typically 30 to 60% ullage by volume in order to provide for efficient mixing whilst
maximising the utilisation capacity of the treatment process. Rotation of the drum 10 ensures
agitation of the animal skin substrate with the treatment liquor and the solid particulate
material within the treatment volume 14. During the course of agitation, treatment liquor and
solid particulate material is caused to flow through the apertures in partition 22 from the
treatment volume 14 to the collecting volume 20. Flow of treatment liquor and solid
particulate material through the partition 22 is facilitated by the action of pumping device 50
located downstream of the collecting volume 20. The drum 10 is preferably mounted about
an axis which is inclined to the horizontal. Inclination of the drum promotes an advantageous
fluid flow of treatment liquor around the substrate as the drum rotates which can aid the
displacement of any solid particulate material that may become adhered to the surface of the
substrate.
[00227] Following its passage into the collecting volume 20, treatment liquor together with
the solid particulate material is conveyed along conduit 26 to the processing system 60. The
solid particulate material is separated from the treatment liquor within the processing system
60 by the action of a separator. The inclusion of a blowing and/or sucking device within the
processing system 60 can enhance the separation of solid particles from the treatment
liquor. Unwanted solids entrained in the treatment liquor flow with the solid particulate
material, are also extracted and exit the processing system 60 via first drain 65. Waste
treatment liquor and effluent generated as a result of the treatment process is removed via
second drain 67. The solid particulate material can be subject to one or more washing and
rinsing operations by a device within the processing system 60 before being recycled to the
upper portion of the drum 10 for re-introduction to the treatment volume 14 and therefore reuse
in the treatment procedure.
[00228] In addition, treatment liquor can be conveyed from the collecting volume 20 along
conduit 26 to be recycled via the processing system 60. A portion or all of the treatment
liquor recycled from the collecting volume 20 can be re-introduced to the upper portion of the
drum 10 from the processing system 60 via conduit 18A and drum inlet 18. The further
introduction of treatment liquor can advantageously serve to "wash off" or displace any solid
particles adhered to the surface of the animal skin substrates. At an appropriate stage in the
treatment process when sufficient agitation with the solid particles is deemed to have
occurred, the re-introduction of solid particles into the treatment volume 14 can be ceased.
With the flow of solid particles into the treatment volume arrested, the drum 10 can continue
to rotate and further treatment liquor introduced into the treatment volume to displace any
remaining solid particles that have not passed through the partition 22 into the collecting
volume 20. Further (or recycled) treatment liquor can continue to be introduced in this
manner for a predetermined period or until a desired separation of solid particles from the
substrates has been achieved.
[00229] Depending on the treatment process performed, the drum can be rotated at
different speeds. Typically, for tannery processes, the drum is caused to rotate at a speed of
from about 1 to about 50 rpm, preferably from about 1 to about 30 rpm, and preferably from
about 1 to 15 rpm. Particularly wherein the treatment process is a beamhouse or a tanning
or a retanning or a fatliquoring or a dyeing process, the drum can be caused to rotate at a
speed of from about 3 to about 14 rpm. Particularly wherein the treatment process is a
beamhouse process, the drum can be caused to rotate at a speed of from about 9 to about
14 rpm. The drum can be caused to rotate at a speed of not more than 15 rpm or a lower
rpm.
[00230] Advantageously, the treatment process when performed in accordance with the
invention demonstrated highly efficient separation of solid particles from the animal skin
substrates. The extent of separation of solid particles from the animal skin substrates can be
determined by calculating the separation efficiency. The separation efficiency can preferably
be calculated by the following steps:
i . recovering the particulate solid material following its use in the treatment process
carried out in the apparatus of the present invention or in the method(s) of the
present invention;
ii. rinsing and drying the particulate solid materials recovered in step i);
iii. recording the weight of recovered particulate solid material - A;
iv. recovering the particulate solid material which remains after step i);
v. rinsing and drying the particulate solid materials recovered in step iv);
vi. recording the weight of recovered particulate solid material - B;
vii. calculating the percentage efficiency by use of the equation : Separation
Efficiency (wt%) = 100 x A / (A + B).
[00231] Preferably, step iv is performed by manually hand picking and shaking the
remaining particulate solid material from the animal skin substrate. The rinsing steps are
useful for removing any animal skin substrate and treatment liquor residues. Preferably, this
is done by water rinsing.
[00232] The separation efficiency of solid particles from the animal skin substrate provided
by the invention may be greater than 90%. Furthermore, separation efficiencies of greater
than 95% and greater than 99% and 99.95% were shown to be possible.
[00233] The above-noted processes employing the apparatus 100 can constitute a primary
means of removing solid particulate material from animal skin substrates. Although the vast
majority (i.e. greater than 90%) of solid particles are typically removed from the animal skin
substrates using the apparatus 100, any remaining solid particles can be removed by one or
more further process steps. Thus, the invention also relates to secondary means of
removing solid particulate material from animal skin substrates.
[00234] Figure 2 illustrates a further apparatus 200 for removing solid particulate material
from animal skin substrates. Particularly, the apparatus 200 can be used as a part of a
secondary solid particulate material removal process following the treatment of the
substrates in the apparatus 100. The apparatus 200 comprises first and second rollers 202,
204 between which the animal skin substrate (S) can be fed. Thus after recovery from the
treatment apparatus 100, the substrates are flattened and unfolded before being passed
between the rollers. Each roller can be in the form of a generally cylindrical brush having a
plurality of bristles upstanding from the surface of a generally cylindrical core. As the animal
skin substrate (S) is fed between the rollers, the brushes of the first roller 202 contact a
lower surface of the animal skin substrate and the brushes of the second roller 204 contact
an upper surface of the animal skin substrate. In this way, the use of the apparatus 200 can
strip any remaining solid particles from the substrate surfaces. The brushes can
advantageously be caused to rotate relative to the animal skin substrate, such as by drive
means. The drive means can be manual, or more preferably can be an electric motor.
[00235] Figure 3 illustrates a further apparatus 300 for removing solid particulate material
from animal skin substrates. The apparatus 300 can also be used as a part of a secondary
solid particulate material removal process following the treatment of the substrates in the
apparatus 100. The apparatus 300 includes tub 310 which is conveniently mounted on a set
of wheels 312. Apparatus 300 can thus be in the form of a trolley. The apparatus 300
comprises first and second rollers 302, 304 between which the animal skin substrate (S) can
be fed. The first and second rollers 302, 304 can be of similar construction, that is, generally
cylindrical brushes to the rollers 202, 204 mentioned above. The rollers are mounted to a
portion of the tub 310 such that they are positioned inwardly with respect to tub sidewall
310a. Particularly, the rollers 302, 304 are respectively connected to roller supports 303,
305 extending from tub sidewall 310a.
[00236] After recovery from the treatment apparatus 100, the animal skin substrates are
loaded into the tub 310. The animal skin substrate (S) can then be pulled between the
rollers whereby brushes of the first roller 302 contact a lower surface of the animal skin
substrate and the brushes of the second roller 304 contact an upper surface of the animal
skin substrate. The brushes can advantageously be caused to rotate relative to the animal
skin substrate, such as by drive means. The drive means can be manual, or more
preferably can be an electric motor. Solid particulate material removed from the substrate in
this manner falls into the interior of the tub 310 and can be retained for further use in
additional treatment processes.
[00237] Throughout the description and claims of this specification, the words "comprise"
and "contain" and variations of them mean "including but not limited to", and they are not
intended to (and do not) exclude other moieties, additives, components, integers or steps.
Throughout the description and claims of this specification, the singular encompasses the
plural unless the context otherwise requires. In particular, where the indefinite article is
used, the specification is to be understood as contemplating plurality as well as singularity,
unless the context requires otherwise.
[00238] Features, integers, characteristics, compounds, chemical moieties or groups
described in conjunction with a particular aspect, embodiment or example of the invention
are to be understood to be applicable to any other aspect, embodiment or example
described herein unless incompatible therewith. All of the features disclosed in this
specification (including any accompanying claims, abstract and drawings), and/or all of the
steps of any method or process so disclosed, may be combined in any combination, except
combinations where at least some of such features and/or steps are mutually exclusive. The
invention is not restricted to the details of any foregoing embodiments. The invention
extends to any novel one, or any novel combination, of the features disclosed in this
specification (including any accompanying claims, abstract and drawings), or to any novel
one, or any novel combination, of the steps of any method or process so disclosed.
[00239] The reader's attention is directed to all papers and documents which are filed
concurrently with or previous to this specification in connection with this application and
which are open to public inspection with this specification, and the contents of all such
papers and documents are incorporated herein by reference.

CLAIMS
1. An apparatus for treating one or more animal skin substrates with a multiplicity of solid
particles and treatment liquor comprising:
a rotatably mounted drum comprising an internal volume having a first portion defining a
treatment volume for retaining said animal substrates and a second portion defining a
collecting volume, wherein the side-walls of said drum are not perforate;
one or more inlets for introducing solid particles and treatment liquor into said treatment
volume;
a partition separating said treatment volume from said collecting volume wherein said
partition allows free passage of solid particles from the treatment volume to the
collecting volume and prevents the passage of the substrate(s) therethrough;
a circulation path for conveying said solid particles from the collecting volume to the
treatment volume; and
a pumping device arranged to pump solid particles and said treatment liquor along a
portion of said circulation path.
2 . An apparatus as claimed in claim 1 wherein the circulation path provides a flow of solid
particles from the collecting volume to the treatment volume and then to the collecting
volume.
3 . An apparatus as claimed in claim 1 or 2 wherein the circulation path provides a flow of
treatment liquor from the collecting volume to the treatment volume and then to the
collecting volume.
4 . An apparatus as claimed in any preceding claim comprising a processing system in said
circulation path wherein said processing system receives said treatment liquor and said
solid particles from the collecting volume of said drum.
5 . An apparatus as claimed in claim 4 wherein said processing system comprises a
separator configured to separate at least a portion of said treatment liquor from said solid
particles.
6 . An apparatus as claimed in any preceding claim comprising a storage vessel for retaining
said solid particles and a dispenser to introduce said solid particles to said treatment
volume.
7 . An apparatus as claimed in any preceding claim wherein a first portion of the circulation
path comprises a conduit having an inlet disposed proximate the lowermost part of the
collecting volume, the conduit extending from said collecting volume.
8 . An apparatus as claimed in claim 7 comprising a first such conduit provided for conveying
solid particles.
9 . An apparatus as claimed in claim 7 comprising one or more such conduits for conveying
both treatment liquor and solid particles.
10. An apparatus as claimed in any preceding claim wherein said drum has an upper
portion comprising at least one inlet to introduce said solid particles into said treatment
volume and at least one inlet for receiving treatment liquor into said treatment volume.
11. An apparatus as claimed in claim 10 when depending through claim 6 wherein said
dispenser communicates with said at least one inlet of said upper portion to introduce
said solid particles into said treatment volume.
12. An apparatus as claimed in claim 10 or 11 when depending through claim 5 wherein
said apparatus comprises a conduit extending from an outlet of the processing system
wherein said conduit is connected to an inlet of the upper portion of the drum.
13. An apparatus as claimed in claim 5 or any of claims 6 to 12 when depending through
claim 5 wherein said processing system comprises a device for removing residual
treatment liquor and deposits from said solid particles.
14. An apparatus as claimed in claim 5 or any of claims 6 to 13 when depending through
claim 5 wherein said processing system comprises one or more outlets for discharging
treatment liquor and/or unwanted matter produced during the treatment process.
15. An apparatus as claimed in any preceding claim wherein said drum comprises a
closure moveable between an open position and a closed position wherein when said
closure is moved to said open position free passage of solid particles and fluids into the
collecting volume from the treatment volume is permitted and wherein when said closure
is moved to said closed position solid particles are prevented from passing into the
collecting volume from the treatment volume whilst the passage of fluids into the
collecting volume from the treatment volume is permitted.
16. An apparatus as claimed in any of claims 1 to 14 wherein said drum comprises a
closure moveable between an open position and a closed position wherein when said
closure is moved to said open position free passage of solid particles and fluids into the
collecting volume from the treatment volume is permitted and wherein when said closure
is moved to said closed position any solid particles and fluids in the treatment volume are
retained in the treatment volume.
17. An apparatus as claimed in any preceding claim wherein said drum is configured to
rotate about an axis which is inclined to the horizontal.
18. An apparatus as claimed in claim 17 wherein a major portion of the treatment volume
extends above the collecting volume.
19. An apparatus as claimed in any preceding claim wherein said pumping device is
arranged in the circulation path external to the drum.
20. An apparatus as claimed in any preceding claim wherein said partition divides the
internal volume of the drum into two portions respectively located at a first end and a
second end.
2 1. An apparatus as claimed in claim 20 wherein treatment liquor and solid particulate
material enter and exit the internal volume of the drum from first and second end regions
of the drum.
22. An apparatus as claimed in any preceding claim wherein said partition comprises a
plurality of apertures.
23. An apparatus as claimed in claim 22 wherein said partition is in the form of a perforate
or reticulate screen.
24. An apparatus as claimed in claim 22 or 23 wherein said apertures have a maximum
dimension of from about 2 to 125mm, or from about 26mm to about 125mm.
25. An apparatus as claimed in any preceding claim wherein said partition comprises
metal, metal alloy, plastic, fibreglass, composite or polymeric materials.
26. An apparatus as claimed in any preceding claim wherein said partition is arranged to
be substantially perpendicular to the axis of rotation of said drum and/or wherein said
partition is planar.
27. An apparatus as claimed in any preceding claim wherein said solid particles can be re
used one or more times for treatment of the animal skin substrate(s) in, with or by the
apparatus of the invention.
28. An apparatus as claimed in any preceding claim wherein said solid particles have an
average particle diameter of from 1mm to 100mm and/or wherein said solid particles have
a length of from 1mm to 100mm.
29. An apparatus as claimed in any preceding claim wherein the solid particles comprise
a multiplicity of polymeric particles, a multiplicity of non-polymeric particles or a mixture of
a multiplicity of polymeric and non-polymeric particles.
30. An apparatus as claimed in any preceding claim wherein said drum has a capacity of
from 500 to 200,000 litres.
3 1. An apparatus as claimed in any preceding claim wherein said treatment volume
comprises at least 50% of said internal volume of said drum.
32. An apparatus as claimed in any preceding claim wherein said collecting volume
comprises not more than 30% of said internal volume of said drum.
33. A method of separating a multiplicity of solid particles from one or more animal skin
substrates during a treatment process comprising:
agitating said animal skin substrates with a multiplicity of solid particles and treatment
liquor in a treatment volume of a rotatably mounted drum wherein the side-walls of said
drum are not perforate,
said drum having a collecting volume separated from the treatment volume by a partition,
wherein said method further comprises allowing the solid particles and treatment liquor to
pass through the partition from the treatment volume to the collecting volume whilst
retaining said animal skin substrates in the treatment volume, and wherein said method is
performed using the apparatus as defined in of any of claims 1 to 32.
34. The method as claimed in claim 33 comprising circulating said treatment liquor from
said collecting volume to said treatment volume to provide a flow of treatment liquor
through the treatment volume and continuing agitation of said animal skin substrates in
said drum for a predetermined period or until a desired separation of solid particles from
said animal skin substrates is achieved.
35. The method as claimed in claim 33 or 34 further comprising conveying said solid
particles and said treatment liquor from the collecting volume, separating at least a
portion of said treatment liquor from said solid particles and re-introducing said solid
particles into said treatment volume.
36. The method as claimed in claim 33, claim 34 or claim 35 comprising the steps of:
i) introducing treatment liquor into said treatment volume and agitating said animal skin
substrates with said solid particles and said treatment liquor in the treatment volume for a
first agitation step;
ii) allowing said treatment liquor to pass through the partition to the collecting volume and
conveying said treatment liquor from the collecting volume along a circulation path;
iii) re-introducing said treatment liquor from said circulation path into said treatment
volume.
37. The method as claimed in claim 36 further comprising separating at least a portion of
said treatment liquor received from the collecting volume from said solid particles before reintroducing
said treatment liquor from said circulation path into said treatment volume.
38. The method as claimed in claim 36 or claim 37 further comprising extracting effluent
and/or unwanted matter from the treatment liquor received from the collecting volume before
re-introducing said treatment liquor from said circulation path into said treatment volume.
39. The method of any of claims 33 to 38 comprising the steps of:
i) introducing said solid particles into said treatment volume and agitating said animal skin
substrates with said solid particles and said treatment liquor in the treatment volume for a
first agitation step;
ii) allowing said solid particles to pass through the partition to the collecting volume and
conveying said solid particles from the collecting volume along a circulation path;
iii) re-introducing said solid particles into said treatment volume from said circulation path
and agitating said animal skin substrates with said solid particles and treatment liquor in
the treatment volume for a subsequent agitation step.
40. The method as claimed in claim 39 further comprising separating at least a portion of
said treatment liquor from said solid particles before re-introducing said solid particles
from said circulation path into said treatment volume for said subsequent agitation step.
4 1. The method as claimed in any of claims 33 to 40 further comprising subjecting said
solid particles to a cleaning operation using a cleaning formulation before re-introducing
said solid particles into said treatment volume for a subsequent agitation step.
42. The method as claimed in claim 4 1 comprising conveying said solid particles from the
collecting volume to a processing system and performing said cleaning operation in said
processing system.
43. The method as claimed in claim 4 1 comprising draining said treatment liquor from the
drum and subjecting said solid particles to said cleaning operation within said drum
before re-introducing said solid particles into said treatment volume for a subsequent
agitation step.
44. The method as claimed in any of claims 33 to 43 wherein said drum comprises a
closure moveable between an open position and a closed position wherein when said
closure is moved to said open position free passage of solid particles and fluids to the
collecting volume from the treatment volume is permitted and wherein when said closure
is moved to said closed position solid particles are prevented from passing into the
collecting volume from the treatment volume whilst the passage of fluids to the collecting
volume from the treatment volume is permitted,
wherein said method comprises moving said closure from said open position to said
closed position or moving said closure from said closed position to said open position at
one or more points during the treatment process.
45. The method as claimed in any of claims 33 to 43 wherein said drum comprises a
closure moveable between an open position and a closed position wherein when said
closure is moved to said open position free passage of solid particles and fluids into the
collecting volume from the treatment volume is permitted and wherein when said closure
is moved to said closed position any solid particles and fluids in the treatment volume are
retained in the treatment volume,
wherein said method comprises agitating said animal skin substrate(s) and said solid
particles in said drum for a predetermined period with said closure in a closed position
and moving said closure to an open position when said predetermined period has
elapsed.
46. The method as claimed in claim 45 wherein said method further comprises
introducing treatment liquor into said drum when said predetermined period has elapsed.
47. The method as claimed in any of claims 33 to 46 wherein said drum is caused to
rotate about an axis which is inclined to the horizontal for at least a portion of said
treatment process.
48. The method as claimed in any of claims 33 to 47 wherein said drum is caused to
rotate at a speed of from about 1 to about 50 rpm, or from about 1 to about 15 rpm.
49. The method as claimed in any of claims 33 to 48 wherein said treatment volume has
an ullage volume of at least 10% by volume.
50. The method as claimed in any of claims 33 to 49 wherein the or each animal skin
substrate is a hide or pelt.
5 1. The method as claimed in any of claims 33 to 50 wherein said treatment process is a
tannery process.
52. The method as claimed in any of claims 33 to 5 1 wherein said treatment process is a
process used in the production of leather.
53. The method as claimed in any of claims 33 to 52 wherein said treatment liquor is
aqueous.
54. The method as claimed in any of claims 33 to 52 wherein said treatment liquor in the
drum is substantially free from water except for that originating from the or each animal
substrate.
55. The method as claimed in any of claims 33 to 54 wherein said treatment liquor
comprises at least one treatment agent selected from tanning agents, re-tanning agents
and tannery process agents.
56. The method as claimed in any of claims 33 to 55 wherein said treatment liquor
comprises at least one colourant.
57. The method as claimed in claim 56 wherein said colourant is selected from one or
more dyes, pigments, optical brighteners or mixtures thereof.
58. The method as claimed in any of claims 33 to 57 wherein said solid particles are re
used one or more times in the same treatment method or for the treatment of further
animal skin substrates in subsequent treatments according to the method.
59. A method as claimed in any of claims 33 to 58 wherein said rotatably mounted drum
comprises an internal volume having a first portion defining said treatment volume for
retaining said animal substrates and a second portion defining said collecting volume.
60. A method as claimed in any of claims 33 to 59 wherein said partition divides the
internal volume of the drum into two portions respectively located at a first end and a
second end, preferably wherein treatment liquor and solid particulate material enter and
exit the internal volume of the drum from first and second end regions of the drum.
61. A method as claimed in any of claims 33 to 60 wherein said partition is arranged to be
substantially perpendicular to the axis of rotation of said drum and/or wherein said
partition is planar.
62. A method of treating one or more animal skin substrates wherein said method
comprises the method of any of claims 33 to 6 1.