IMPROVED CLEANING METHOD
Field of the Invention
[0001] The present invention relates to the aqueous cleaning of soiled substrates,
specifically textile fibres and fabrics, using a cleaning system comprising polymeric
particles. More specifically, the invention is concerned with the use of polymeric
particles in a system designed to improve mechanical interaction between said particles
and the fabrics, and allow the easy removal of said particles from the fabrics after the
cleaning process is complete, thereby facilitating their re-use in subsequent cleaning
processes.
Background to the Invention
[0002] Aqueous cleaning processes are a mainstay of both domestic and industrial
textile fabric washing. On the assumption that the desired level of cleaning is achieved,
the efficacy of such processes is usually characterised by their levels of consumption of
energy, water and detergent. In general, the lower the requirements with regard to
these three components, the more efficient the washing process is deemed. The
downstream effect of reduced water and detergent consumption is also significant, as
this minimises the need for disposal of aqueous effluent, which is both extremely costly
and detrimental to the environment.
[0003] Such washing processes, whether involving domestic washing machines or
their industrial equivalents (usually referred to as washer extractors) involve aqueous
submersion of fabrics followed by soil removal, aqueous soil suspension, and water
rinsing. In general, the higher the level of energy (or temperature), water and detergent
which is used, the better the cleaning. The key issue, however, concerns water
consumption, as this sets the energy requirements (in order to heat the wash water), and
the detergent dosage (to achieve the desired detergent concentration). In addition, the
water usage level defines the mechanical action of the process on the fabric, which is
another important performance parameter; this is the agitation of the cloth surface
during washing, which plays a key role in releasing embedded soil. In aqueous
processes, such mechanical action is provided by the water usage level, in combination
with the drum design for any particular washing machine. In general terms, it is found
that the higher the water level in the drum, the better the mechanical action. Hence,
there is a dichotomy created by the desire to improve overall process efficiency (i.e. the
reduction of energy, water and detergent consumption) , and the need for efficient
mechanical action in the wash. For domestic washing in particular there are defined
wash performance standards specifically designed to discourage the use of such higher
levels in practice, in addition to the obvious cost penalties which are associated with
such usage.
[0004] Current efficient domestic washing machines have made significant strides
towards minimising their consumptions of energy, water and detergent. EU Directive
92/75/CEE sets a standard which defines washing machine energy consumption in
kWh/cycle (cotton setting at 60 °C) , such that an efficient domestic washing machine will
typically consume < 0.19 kWh/kg of washload in order to obtain an 'A' rating . If water
consumption is also considered, then 'A' rated machines use < 9.7 litres/kg of washload.
[0005] Detergent dosage is then driven by manufacturer recommendations but, again,
in the domestic market, for a concentrated liquid formulation , a quantity of 35 ml (or 37
g) for a 4-6 kg washload in soft and medium hardness water, increasing to 52 ml (or 55
g) for a 6-8 kg washload (or in hard water or for very dirty items) is typical (see, for
example, Unilever pack dosage instructions for Persil® Small & Mighty). Hence, for a 4-6
kg washload in soft/medium water hardness, this equates to a detergent dosage of 7.4-
9.2 g/kg whilst, for a 6-8 kg washload (or in hard water or for very dirty items), the range
is 6.9-9.2 g/kg .
[0006] Energy, water and detergent consumptions in the industrial washing process
(washer extractors) are considerably different, however, and usages of all three
resources are less constrained, since these are principal factors in reducing cycle time -
which is, of course, more of a consideration than in the case of domestic processes. For
a typical industrial washer extractor (25 kg washload rated and above), energy
consumption is > 0.30 kWh/kg , water is at -20 litres/kg , and detergent is much more
heavily dosed than for domestic washing . The exact level of detergent used will depend
on the amount of soiling , but a range of 18-70 g/kg is representative.
[0007] Thus, it can be taken from the above discussion that it is the performance levels
in the domestic sector which set the highest standard for an efficient fabric washing
process, and that these are: an energy consumption of < 0.19 kWh/kg , a water usage of
< 9.7 litres/kg , and a detergent dosage of approximately 8.0 g/kg (8.5 ml/kg). However,
as previously observed, it is becoming increasingly difficult to reduce the water (and,
hence, energy and detergent) levels in a purely aqueous process, due to the minimum
requirement to wet the fabric thoroughly, the need to provide sufficient excess water to
suspend the soil removed in an aqueous liquor and, finally, the necessity to rinse the
fabric.
[0008] Heating of the wash water is then the principal use of energy, and a minimum
level of detergent becomes necessary in order for an effective concentration to be
reached at the operating wash temperature. Means to improve mechanical action
without increasing the water level used would, therefore, make any aqueous wash
process significantly more efficient (i.e. yield further reductions in energy, water and
detergent consumption). It should be noted that mechanical action itself has a direct
effect on the detergent level, since the greater the level of soil removal which is achieved
through physical force, the less that is required of the detergent chemistry. However,
increasing the mechanical action in a purely aqueous washing process has certain
associated drawbacks. Fabric creasing readily occurs in such processes, and this acts
to concentrate the stresses from mechanical action at each crease, resulting in localised
fabric damage. Prevention of such fabric damage (i.e. fabric care) is of primary concern
to the domestic consumer and the industrial user.
[0009] In the light of these challenges which are associated with aqueous washing
processes, the present inventors have previously devised a new approach to the
problem, which allows the deficiencies demonstrated by the methods of the prior art to
be overcome. The method which is provided eliminates the requirement for the use of
large volumes of water, but is still capable of providing an efficient means of cleaning
and stain removal, whilst also yielding economic and environmental benefits.
[0010] 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. Preferably, the substrate is wetted so as to
achieve a substrate to water ratio of between 1:0.1 to 1:5 w/w, and optionally, the
formulation additionally comprises at least one cleaning material, which typically
comprises a surfactant, which most preferably has detergent properties. In preferred
embodiments, the substrate comprises a textile fibre and the polymeric particles may, for
example, comprise particles of polyamides, polyesters, polyalkenes, polyurethanes or
their copolymers, but are most preferably in the form of nylon beads.
[001 1] The use of this polymeric particle-based cleaning method, however, presents a
requirement for the cleaning particles to be efficiently separated from the cleaned
substrate at the conclusion of the cleaning operation, and this issue is addressed in WOA-
20 10/094959, which provides a novel design of cleaning apparatus requiring the use
of two internal drums capable of independent rotation, and which finds application in
both industrial and domestic cleaning processes.
[0012] In co-pending WO-A-201 1/064581 , there is provided a further apparatus which
facilitates efficient separation of cleaning particles from the cleaned substrate at the
conclusion of the cleaning operation, and which comprises a perforated drum and a
removable outer drum skin which is adapted to prevent the ingress or egress of fluids
and solid particulate matter from the interior of the drum, the cleaning method requiring
attachment of the outer skin to the drum during a wash cycle, after which the skin is
removed prior to operating a separation cycle to remove the cleaning particles, following
which the cleaned substrate is removed from the drum.
[0013] In a further development of the apparatus of WO-A-201 1/064581 , there is
disclosed in co-pending WO-A-201 1/098815 a process and apparatus which provides for
continuous circulation of the polymeric cleaning particles during the cleaning process,
and thereby dispenses with the requirement for the provision of an outer skin.
[0014] The apparatus and methods disclosed in the foregoing prior art documents
have been highly successful in providing an efficient means of cleaning and stain
removal which also yields significant economic and environmental benefits. In seeking
to further develop the method and apparatus of the cleaning process, the present
inventors have now sought to provide a process which offers still further benefits in
terms of reduced power and consumable requirements, and have succeeded in refining
the technology such that it is possible to achieve at least equivalent cleaning
performance whilst employing significantly reduced levels of detergents and,
surprisingly, at much lower process temperatures. In addition they have increased the
level of removal of the polymeric particles from the fabric washload at the end of the
cleaning process in the washing apparatus used. It is of course a pre-requisite for such
polymeric cleaning processes that particle removal is maximised, both for user
convenience and to enable particle re-use in subsequent cleaning processes.
[0015] Therefore, in the presently claimed invention, the inventors have sought, by
careful control of polymeric particle size, shape and density, and also process
parameters, to provide a process in which the cleaning effect achieved as a
consequence of mechanical interaction of a soiled substrate with the cleaning media is
optimised. The inventors have succeeded in achieving a cleaning process which
facilitates excellent cleaning performance at surprisingly low cleaning temperatures (i.e.
low energy) and with reduced levels of added detergents, whilst also maintaining the
original low water consumption. As previously discussed, effective targets for these
savings would be significant reductions below an energy consumption of 0.1 9 kWh/kg, a
water usage of 9.7 litres/kg, and a detergent dosage of 8.0 g/kg (8.5 ml/kg), whilst
delivering parity cleaning performance. The current invention allows a new washing
process capable of exceeding these targets, whilst also facilitating reduced localised
fabric damage in the washed substrate by virtue of the increased uniformity of the
mechanical action of the particles with the fabric surface.
[0016] In addition, removal levels of polymeric particles from the fabric washload at the
end of the cleaning process have been increased to > 99.9%, this parameter being
defined as:
Bead Removal Level = 100 - ((BRet/B ot) x 00)
expressed as a percentage, where BRet is the number of beads retained by the
washload, and BTot is the total number of beads used in the cleaning process. Once
removed the particles are then re-used in subsequent cleaning processes.
Summary of the Invention
[0017] The present invention derives from an appreciation on the part of the inventors
that optimum cleaning performance can be achieved as a result of improved mechanical
interaction between substrate and cleaning media, as well as controlled soil adsorption
and absorption onto the surface of the media. This can be effected as a function of the
chemical composition, number, size, shape and density of the particles of cleaning
media and the free volume within the vessel in which the cleaning operation takes place,
in addition to the G force dictated by its speed of rotation. Free volume in this context
refers to the space inside the vessel which remains unoccupied by washload or
particulate cleaning media, and G force is defined on the basis of the centripetal forces
which are acting.
[0018] Thus, according to a first aspect of the present invention, there is provided a
method for the cleaning of a soiled substrate, said method comprising treating the
substrate with a solid particulate cleaning material and wash water, said treatment being
carried out in an apparatus comprising a drum comprising perforated side walls and
having a capacity of between 5 and 50 litres for each kg of fabric in the washload,
wherein said solid particulate cleaning material comprises a multiplicity of polymeric
particles at a particle to fabric addition level of 0.1 :1-10:1 by mass, each particle being
substantially cylindrical or spherical in shape and having an average density in the range
of 0.5-2.5 g/cm3 and an average volume in the range of 5-275 mm3, and wherein said
drum comprising perforated side walls is rotated at a speed which generates G forces in
the range of from 0.05 to 900 G.
[0019] In the context of the presently claimed invention, it will be appreciated that the
shape descriptors for the polymeric particles are idealised and that, in practice,
polymeric particles cut from a molten polymer lace, either in air or in another fluid, will be
less than perfectly cylindrical or spherical. Thus, "cylindrical" in this context means a
particle which has either a circular or oval cross section, and an aspect ratio of length
divided by width (shortest axis in the case of oval cross sections) typically in the region
of from 0.5-10. Such particles are also characterised by the surfaces forming their cross
section being flatter than the surface forming their circumference.
[0020] "Spherical" in this context means a particle which does not have a cross section
with flat surfaces, and an aspect ratio of length divided by width of ~ 1. Perfect spheres
may also optionally be used as polymeric particles, although these are generally more
expensive as their manufacture involves either an injection or compression moulding
step.
[0021] In one embodiment, cylindrical particles of oval cross section have a major
cross section axis length (denoted a) of 2.0-6.0 mm, a minor cross section axis length
(denoted b) of 1.3-5.0 mm (a>b), and a length (denoted h) of 1.5-6.0 mm (h/b is typically
in the range of 0.5-10). In an alternative embodiment, if the cylindrical particle cross
section is circular, then the diameter of the particle (denoted dc) is 1.3-6.0 mm, and its
length (denoted hc) is 1.5-6.0 mm (hc/dc is typically in the range of 0.5-1 0).
[0022] In a further embodiment, spherical particles have a diameter (denoted ds) of
2.0-8.0 mm. In the event that perfect spheres are used, then the diameter (denoted dps)
is again typically from 2.0-8.0 mm.
[0023] In typical embodiments of the invention, the claimed method additionally
provides for separation and recovery of the polymeric particles, which are then re-used
in subsequent cleaning processes.
[0024] The polymeric particles may comprise either foamed or unfoamed polymeric
materials. Furthermore, the polymeric particles may comprise polymers which are either
linear or crosslinked.
[0025] In certain embodiments of the invention, the drum comprising perforated side
walls comprises a rotatably mounted cylindrical cage.
[0026] The volume of wash water added to the system provides a wash water to fabric
ratio which is typically between 5.0:1 and 0.1 : 1 w/w, and the overall volumes of water
which are employed (including rinse water) are significantly lower than in conventional
washing processes.
[0027] In typical embodiments of the invention, the formulation additionally comprises
at least one additional cleaning agent, which optionally comprises at least one detergent
composition.
[0028] The generation of suitable G forces, in combination with the action of the solid
particulate cleaning material, is a key factor in achieving an appropriate level of
mechanical interaction of the particles with the soiled substrate. G is a function of the
drum size and the speed of rotation of the drum and, specifically, is the ratio of the
centripetal force generated at the inner surface of the cage to the static weight of the
washload. Thus, for a cage of inner radius r (m), rotating at R (rpm), with a washload of
mass M (kg), and an instantaneous tangential velocity of the cage v (m/s), and taking g
as the acceleration due to gravity at 9.81 m/s2:
Centripetal force = Mv2/r
Washload static weight = Mg
v = 2TTrR/60
Hence, G = 4TT2r2R2/3600rg = 4TT2rR2/3600g = 1. 18 x 10 3rR2
When, as is usually the case, r is expressed in centimetres, rather than metres, then:
G = 1. 1 18 x 10 5rR2
Hence, for a drum of radius 48 cm rotating at 800 rpm, G = 350.6.
[0029] In an embodiment of the invention, a cylindrical drum having a diameter of 98
cm is rotated at a speed of 30-800 rpm in order to generate G forces of 0.49-350.6 at
different stages during the cleaning process. In examples of alternative embodiments of
the invention, a 48 cm diameter drum rotating at 1600 rpm can generate 688 G, whilst a
60 cm diameter drum at the same speed of rotation generates 860 G.
[0030] In certain embodiments of the invention, said polymeric particles comprise
polyalkenes such as polyethylene and polypropylene, polyamides, polyesters or
polyurethanes, which may be foamed or unfoamed. Furthermore, said polymers may be
linear or crosslinked. Typically, however, said polymeric particles comprise polyamide or
polyester particles, most particularly particles of nylon, polyethylene terephthalate or
polybutylene terephthalate, frequently in the form of beads. Said polyamides and
polyesters are found to be particularly effective for aqueous stain/soil removal, whilst
polyalkenes are especially useful for the removal of oil-based stains.
[0031] Optionally, copolymers of the above polymeric materials may be employed for
the purposes of the invention. Specifically, the properties of the polymeric materials may
be tailored to specific requirements by the inclusion of monomeric units which confer
particular properties on the copolymer. Thus, the copolymers may be adapted to attract
particular staining materials by comprising monomers which, inter alia, are ionically
charged, or include polar moieties or unsaturated organic groups.
[0032] The polymeric particles are of such a shape and size as to allow for good
flowability and intimate contact with the soiled substrate, which typically comprises a
textile fabric. In the context of the present invention, therefore, said particles comprise
cylindrical or spherical beads. It is found that the combination of particle size, shape and
density is such that the mechanical interaction of the particle with the fabric is optimised,
it being sufficiently vigorous to provide effective cleaning but, at the same time, uniform
and gentle enough to reduce fabric damage when compared with conventional aqueous
processes. It is, in particular, the uniformity of the mechanical action generated by the
chosen particles across the entire fabric surface that is the key factor in this regard. The
particle parameters are also controlled so as to allow for easy separation of the particles
from the fabric washload at the end of the wash process. Thus, particle size and shape
may be controlled in order to minimise entanglement with the fabric, and the combination
of suitable particle density with low G (< 1) and high free volume in the washing machine
tumbling process together promote particle removal under gravity through the
perforations in the drum sidewalk
[0033] The particles may have smooth or irregular surface structures and can be of
solid or hollow construction. Particles have an average density in the range of 0.5-2.5
g/cm3, preferably from 0.55-2.0 g/cm3, more preferably from 0.6-1 .9 g/cm3. The average
volume of the particles is in the range of 5-275 mm3, preferably from 8-140 mm3, more
preferably from 10-120 mm3.
[0034] In the case of cylindrical beads of oval cross section, the major cross section
axis length, a, is typically in the range of from 2.0-6.0 mm, more typically from 2.2-5.0
mm, most typically from 2.4-4.5 mm, and the minor cross section axis length, b, is
typically in the range of from 1.3-5.0 mm, more typically from 1.5-4.0 mm, and most
typically from 1.7-3.5 mm (a > b). The length of such beads, h, is typically from 1.5-6.0
mm, more typically from 1.7-5.0 mm, and most typically from 2.0-4.5 mm (h/b typically in
the range of 0.5-1 0).
[0035] For cylindrical beads of circular cross section, the typical cross section
diameter, dc, is in the range of from 1.3-6.0 mm, more typically from 1.5-5.0 mm, and
most typically from 1.7-4.5 mm. The typical length, hc, of such beads is again from 1.5-
6.0 mm, more typically from 1.7-5.0 mm, and most typically from 2.0-4.5 mm (hc/dc
typically in the range of 0.5-10).
[0036] In the case of spherical beads, the diameter, ds, is typically in the range of from
2.0-8.0 mm, more typically from 2.2-5.5 mm, and most typically from 2.4-5.0 mm.
[0037] In embodiments wherein the beads comprise perfect spheres, the diameter, dps ,
is typically in the range of from 2.0-8.0 mm, more typically from 3.0-7.0 mm, and most
typically from 4.0-6.5 mm.
[0038] Said rotatably mounted cylindrical cage is comprised in any suitable cleaning
apparatus comprising a housing and access means, allowing access to the interior of
said cylindrical cage, suitable examples of which are disclosed in WO-A-201 0/094959,
WO-A-20 11/064581 and WO-A-201 1/09881 5.
[0039] Optionally, said rotatably mounted cylindrical cage may be concentrically
located within a rotatably mounted cylindrical drum having a greater diameter than said
cage, wherein said cage and said drum are concentrically located within a stationary
cylindrical drum having a greater diameter than said rotatably mounted drum, and
wherein said rotatably mounted cylindrical cage and said rotatably mounted cylindrical
drum are adapted to rotate independently.
[0040] More preferably, however, said rotatably mounted cylindrical cage is mounted in
a first chamber within said housing means, which also comprises a second chamber
located adjacent said cylindrical cage. Said apparatus typically also comprises at least
one recirculation means and a multiplicity of delivery means.
[0041] In certain embodiments of the invention, said apparatus additionally comprises
sealing means, removably attached to the outer surface of the cylindrical side walls of
said rotatably mounted cylindrical cage, and adapted to prevent the ingress or egress of
fluids and solid particulate matter from the interior of said cage.
[0042] In alternative embodiments of the invention, said apparatus additionally
comprises pumping means, and up to 60% of the surface area of the perforated side
walls of said rotatably mounted cylindrical cage comprises perforations, and said
perforations comprise holes having a diameter of no greater than 25.0 mm.
[0043] As a consequence of employing the cleaning method of the present invention,
excellent cleaning performance may be achieved whilst using reduced levels of
detergents and surprisingly low cleaning temperatures (i.e. lower energy consumption),
whilst also maintaining low water consumption levels. Thus, cleaning operations
according to the invention, whilst possible at temperatures of up to 95°C, are typically
carried out at temperatures not exceeding 75°C, and optimum performance is generally
achieved at 5-40 °C. As an approximate guide, it is found that if a conventional aqueous
cleaning process requires a wash temperature of T°C, then the process according to the
present invention will provide superior cleaning at temperatures in the range of T-10°C to
T-25 C. Removal of the beads from the fabric washload at the end of the cleaning
process is expedited on the basis of the specific size, shape and density of the beads
used, and also by control of process parameters, in order to enable bead re-use in
subsequent cleaning processes.
[0044] Thus, the present inventors have provided a process for the cleaning of soiled
substrates which provides improved cleaning performance, reduced damage to the
substrate being cleaned, and significantly reduced consumption of energy, detergent
and water. These improvements result from improved mechanical interaction between
the cleaning material and the substrate, which result from the careful selection of both
apparatus parameters and the physical properties of the solid particulate cleaning
material as herein defined. Furthermore, by virtue of this selection of parameters and
properties, the process allows for the efficient collection of the solid particulate cleaning
material after completion of the process such that it may be re-used in subsequent
cleaning procedures.
[0045] A further aspect of the invention envisages a cleaning composition as
hereinbefore defined comprising a solid particulate cleaning composition and at least
one additional cleaning agent. Typically, said at least one additional cleaning agent
comprises at least one detergent composition.
Detailed Description of the Invention
[0046] In apparatus employed in the method of the invention, the access means
typically comprises a hinged door mounted in the housing, which may be opened to
allow access to the inside of the cylindrical cage, and which may be closed in order to
provide a substantially sealed system. Preferably, the door includes a window.
[0047] Said rotatably mounted cylindrical cage may be mounted vertically within said
housing means but, most preferably, is mounted horizontally within said housing means.
Consequently, in preferred embodiments of the invention, said access means is located
in the front of the apparatus, providing a front-loading facility. When the rotatably
mounted cylindrical cage is vertically mounted within the housing means, the access
means is located in the top of the apparatus, providing a top-loading facility.
[0048] Rotation of said rotatably mounted cylindrical cage is effected by use of drive
means, which typically comprises electrical drive means, in the form of an electric motor.
Operation of said drive means is effected by control means which may be programmed
by an operative.
[0049] The method according to the invention typically comprises performing, in
sequence, the steps of:
(a) washing;
(b) first extraction of excess water;
(c) first separation of polymeric particles;
(d) rinsing;
(e) second extraction of excess water;
(f) optionally repeating steps (d) and (e) at least once; and
(g) second separation of polymeric particles.
[0050] Said first separation of polymeric particles (beads) typically removes > 50% of
the particles, whilst the second separation of polymeric particles ensures removal of
> 99.9% of these particles. Optionally, the first separation of polymeric particles can be
extended to provide removal of > 99.9% of particles, but it is more efficient to take
advantage of steps (d) and (e), as these also inherently remove some particles, before
moving to step (g) for final separation. This is particularly true if steps (d) and (e) are
repeated.
[0051] Preferably, steps (d) and (e) are repeated several times, typically at least 2-3
times, but possibly up to 10 times.
[0052] Said rotatably mounted cylindrical cage more preferably has a volume of
between 5 and 50 litres for each kg of fabric in the washload. Preferred rates of rotation
of said rotatably mounted cylindrical cage are sufficient to give G forces of between 0.05
and 900 G. Typically the washing process is carried out at between 0.05 and 0.95 G,
and the rinsing water is added under similar conditions, before extraction of the excess
water at higher G force, typically 5.5 to 350 G. Final separation of the beads from the
fabric is then carried out again at 0.05 to 0.95 G. After separation, the beads are
recovered for use in subsequent cleaning processes.
[0053] Thus, for a 98 cm diameter cage, the speeds of rotation are advantageously in
the range of 10-800 rpm. Typically the washing process is carried out between 10 and
42 rpm and the rinsing water is added under similar conditions, before extraction of the
excess water takes place at 100-800 rpm. Final separation of the beads from the fabric
is then carried out at 10-42 rpm, and the separated beads are recovered for use in
subsequent cleaning processes.
[0054] According to the method of the invention, said apparatus operates in
conjunction with soiled substrates and cleaning media comprising a solid particulate
material, which is most preferably in the form of a multiplicity of polymeric particles.
These polymeric particles are required to be efficiently circulated to promote optimum
cleaning performance and the apparatus, therefore, preferably includes circulation
means. Thus, the inner surface of the cylindrical side walls of said rotatably mounted
cylindrical cage preferably comprises a multiplicity of spaced apart elongated protrusions
affixed essentially perpendicularly to said inner surface. Preferably, said protrusions
additionally comprise air amplifiers which are typically driven pneumatically and are
adapted so as to promote circulation of a current of air within said cage. Typically said
apparatus comprises from 3 to 10, most preferably 4, of said protrusions, which are
commonly referred to as lifters.
[0055] In operation, agitation is provided by rotation of said rotatably mounted
cylindrical cage. However, in preferred embodiments of the invention, there is also
provided additional agitating means, in order to facilitate the efficient removal of residual
solid particulate material at the conclusion of the cleaning operation. Preferably, said
agitating means comprises an air jet.
[0056] Said housing means is connected to standard plumbing features, thereby
preferably providing at least one recirculation means, in addition to a multiplicity of
delivery means, by virtue of which at least water and, optionally, cleaning agents such as
surfactants, enzymes and bleaches may be introduced into the apparatus. Said
apparatus may additionally comprise means for circulating air within said housing
means, and for adjusting the temperature and humidity therein. Said means may
typically include, for example, a recirculating fan, an air heater, a water atomiser and/or
a steam generator. Additionally, sensing means may also be provided for determining
the temperature and humidity levels within the apparatus, and for communicating this
information to the control means.
[0057] According to certain embodiments of the invention, the at least one recirculation
means facilitates recirculation of said solid particulate material from a second chamber
to said rotatably mounted cylindrical cage, for re-use in subsequent cleaning processes.
Preferably, first recirculation means comprises ducting connecting said chamber and
said rotatably mounted cylindrical cage. More preferably, said ducting comprises
separating means for separating said solid particulate material from water and control
means, adapted to control entry of said solid particulate material into said cylindrical
cage.
[0058] Recirculation of solid particulate matter from said chamber to said rotatably
mounted cylindrical cage is achieved by the use of pumping means comprised in said
first recirculation means, wherein said pumping means are adapted to deliver said solid
particulate matter to said separating means and said control means, adapted to control
the re-entry of said solid particulate matter into said rotatably mounted cylindrical cage.
[0059] Preferably, said apparatus additionally includes a second recirculation means,
allowing for the return of water separated by said separating means to said second
chamber, thereby facilitating re-use of said water in an environmentally beneficial
manner. Preferably, said chamber comprises additional pumping means to promote
circulation and mixing of the contents thereof.
[0060] In a typical operation of a cleaning cycle according to the method of the
invention, soiled garments are first placed into said rotatably mounted cylindrical cage.
Tumbling begins (G < 1) and, then, the necessary amount of wash water, together with
any required additional cleaning agent, are added to said rotatably mounted cylindrical
cage. When the substrate has been uniformly wetted out (typically 1-2 minutes), the
solid particulate cleaning material is also added to the rotatably mounted cylindrical
cage. Optionally, said materials are introduced via the first recirculation means into the
cylindrical cage. Alternatively, said cleaning agent may, for example, be pre-mixed with
said wash water and added via said separating means located adjacent said cylindrical
cage.
[0061] During the course of agitation by rotation of the cage, the fluids and a quantity
of the solid particulate material exit through the perforations in the cage and into a
second chamber of the apparatus. Thereafter, the solid particulate material may be re
circulated via the first recirculation means such that it is transferred to said separating
means, from which it is returned, in a manner controlled by said control means, to the
cylindrical cage for continuation of the washing operation. This process of continuous
circulation of the solid particulate material continues throughout the washing operation
until cleaning is completed.
[0062] Thus, the solid particulate material which exits through the perforations in the
walls of said rotatably mounted cylindrical cage and into said second chamber is
recirculated and reintroduced through said separation means and, by operation of
control means, back into said cage, thereby to continue the cleaning operation.
[0063] Typically, a wash cycle according the method of the invention comprises the
steps of:
(i) introducing a solid particulate cleaning material and water into a
second chamber of an apparatus as hereinbefore described;
(ii) agitating said solid particulate cleaning material and water;
(iii) loading at least one soiled substrate into said rotatably mounted
cylindrical cage via access means;
(iv) closing the access means so as to provide a substantially sealed
system;
(v) causing the rotatably mounted cylindrical cage to rotate whilst
introducing said wash water and any required additional cleaning
agent to uniformly wet out the substrate;
(vi) introducing said solid particulate cleaning material into said
rotatably mounted cylindrical cage, and operating the apparatus
for a wash cycle, wherein said rotatably mounted cylindrical cage
continues to rotate, and wherein fluids and solid particulate
cleaning material are caused to fall through perforations in said
rotatably mounted cylindrical cage into said second chamber in a
controlled manner;
(vii) operating pumping means so as to transfer fresh solid particulate
cleaning material and recycle used solid particulate cleaning
material to separating means;
(viii) operating control means so as to add said fresh and recycled
solid particulate cleaning material to said rotatably mounted
cylindrical cage in a controlled manner; and
(ix) continuing with steps (vi), (vii) and (viii) as required to effect
cleaning of the soiled substrate.
[0064] Optionally, said solid particulate cleaning material and water may be introduced
into said rotatably mounted cylindrical cage via recirculating means. More preferably,
however, said water is introduced into said rotatably mounted cylindrical cage via dosing
means such as, for example, a fixedly mounted spray nozzle. Most conveniently, said
spray nozzle may be fixedly mounted on said access means.
[0065] Preferably, additional cleaning agents are employed in said method, as further
discussed below. Said additional cleaning agents may be added to said second
chamber of said apparatus with said solid particulate cleaning material and introduced,
via the first recirculation means, into the cylindrical cage. Alternatively, an additional
cleaning agent is pre-mixed with water and added to said cylindrical cage via the
separating means during step (v). More preferably, however, said additional cleaning
agents are added to said cylindrical cage via said dosing means. The method of the
invention facilitates the use of reduced quantities of said additional cleaning agents.
[0066] In preferred embodiments of the invention, said cleaning agents may be added
to said cylindrical cage in multiple dosing steps during the cleaning operation, rather
than a single dosing step.
[0067] Preferably, pumping of said fresh and recycled solid particulate cleaning
material proceeds at a rate sufficient to maintain approximately the same level of
cleaning material in said rotatably mounted cylindrical cage throughout the cleaning
operation, and to ensure that the ratio of cleaning material to soiled substrate stays
substantially constant until the wash cycle has been completed.
[0068] On completion of the wash cycle, feeding of solid particulate cleaning material
into the rotatably mounted cylindrical cage ceases and the speed of rotation of the cage
is gradually increased in order to effect a measure of drying of the cleaned substrate.
Some solid particulate material is removed at this stage. Typically, the cage is rotated at
a rotation speed of between 100 and 800 rpm in order to achieve drying; for a 98 cm
diameter cage, a suitable speed of rotation would be around 600 rpm. Subsequently,
rotation speed is reduced and returned to the speed of the wash cycle so as to allow for
final removal of the solid particulate cleaning material. After separation, the solid
particulate cleaning material may be recovered in order to allow for re-use in subsequent
cleaning processes.
[0069] Optionally, following initial drying at high rpm, said method may additionally
comprise a rinsing operation, wherein additional water may be added to said rotatably
mounted cylindrical cage in order to effect complete removal of any additional cleaning
agent employed in the cleaning operation. Water may be added to said cylindrical cage
via said separating means, or via dosing means such as, for example, a fixedly mounted
spray nozzle. Most conveniently, said spray nozzle may be fixedly mounted on said
access means. Water may also be added to said cylindrical cage by overfilling the
second chamber of said apparatus with water such that it enters the first chamber and
thereby enters into said rotatably mounted cylindrical cage. Following rotation at the
same speed as during the wash cycle, water is removed from said cage by allowing the
water level to fall, as appropriate, and again increasing the speed of rotation to, typically,
100-800 rpm in order to achieve a measure of drying of the substrate; a speed of
rotation of around 600 rpm would, once again, be appropriate for a 98 cm diameter
cage. Said rinsing and drying cycles may be repeated as often as desired.
[0070] Optionally, said rinse cycle may be used for the purposes of substrate
treatment, involving the addition of treatment agents such as fluorescent brighteners,
perfumes, softeners and starch to the rinse water.
[0071] Said solid particulate cleaning material is preferably subjected to a cleaning
operation in said second chamber by sluicing said chamber with clean water in the
presence or absence of a cleaning agent, which may be selected from at least one of
surfactants, enzymes and bleaches. Alternatively, cleaning of the solid particulate
cleaning material may be achieved as a separate stage in said rotatably mounted
cylindrical cage. After cleaning, the solid particulate cleaning material is recovered such
that is available for use in subsequent cleaning processes.
[0072] Generally, any remaining solid particulate cleaning material on said at least one
substrate may be easily removed by shaking the at least one substrate. If necessary,
however, further remaining solid particulate cleaning material may be removed by
suction means, preferably comprising a vacuum wand.
[0073] The method of the invention may be applied to the cleaning of any of a wide
range of substrates including, for example, plastics materials, leather, paper, cardboard,
metal, glass or wood. In practice, however, said method is principally applied to the
cleaning of substrates comprising textile fibres and fabrics, and has been shown to be
particularly successful in achieving efficient cleaning of textile fabrics which may, for
example, comprise either natural fibres, such as cotton, or man-made and synthetic
textile fibres, for example nylon 6,6, polyester, cellulose acetate, or fibre blends thereof.
[0074] Most typically, the solid particulate cleaning material comprises a multiplicity of
polymeric particles which comprise polyamide or polyester particles, most particularly
particles of nylon, polyethylene terephthalate or polybutylene terephthalate, or
copolymers thereof, most preferably in the form of beads. The polymers may be foamed
or unfoamed, and may be linear or crosslinked. Various nylon or polyester homo- or copolymers
may be used including, but not limited to, Nylon 6, Nylon 6,6, polyethylene
terephthalate and polybutylene terephthalate. Preferably, the nylon comprises Nylon 6,6
homopolymer having a molecular weight in the region of from 5000 to 30000 Daltons,
preferably from 10000 to 20000 Daltons, most preferably from 15000 to 16000 Daltons.
The polyester will typically have a molecular weight corresponding to an intrinsic
viscosity measurement in the range of from 0.3-1 .5 dl/g as measured by a solution
technique such as ASTM D-4603.
[0075] Optionally, the properties of the copolymers may be adapted, for example in
order to attract particular staining materials, by including monomer units in the polymer
chain which, inter alia, are ionically charged, or include polar moieties or unsaturated
organic groups. Examples of such groups may include, for example, acid or amino
groups, or salts thereof, or pendant alkenyl groups.
[0076] The volume of wash water added to the system is calculated so as to achieve a
wash water to fabric ratio which is typically between 5.0:1 and 0.1 : 1 w/w; more typically,
the ratio is between 2.0:1 and 0.8:1 , with particularly favourable results having been
achieved at ratios such as 1.75:1 , 1.5:1 , 1.2:1 and 1. 1 : 1 . Most conveniently, the
required amount of water is introduced into the rotatably mounted cylindrical cage of the
apparatus after loading of the soiled substrate into said cage. An additional amount of
water will migrate into the cage during the circulation of the solid particulate cleaning
material, but the amount of carry over is minimised by the action of the separating
means.
[0077] Whilst, in one embodiment, the method of the invention envisages the cleaning
of a soiled substrate by the treatment of a moistened substrate with a formulation which
essentially consists only of a multiplicity of polymeric particles, in the absence of any
further additives, in more preferred embodiments the formulation additionally comprises
at least one additional cleaning agent. Said at least one cleaning agent preferably
comprises at least one detergent composition.
[0078] The principal components of the detergent composition comprise cleaning
components and post-treatment components. Typically, the cleaning components
comprise surfactants, enzymes and bleach, whilst the post-treatment components
include, for example, anti-redeposition additives, perfumes and optical brighteners.
[0079] However, the detergent formulation may optionally include one or more other
additives such as, for example builders, chelating agents, dye transfer inhibiting agents,
dispersants, enzyme stabilizers, catalytic materials, bleach activators, polymeric
dispersing agents, clay soil removal agents, suds suppressors, dyes, structure
elasticizing agents, fabric softeners, starches, carriers, hydrotropes, processing aids
and/or pigments.
[0080] Examples of suitable surfactants may be selected from non-ionic and/or anionic
and/or cationic surfactants and/or ampholytic and/or zwitterionic and/or semi-polar
nonionic surfactants. The surfactant is typically present at a level of from about 0.1%,
from about 1%, or even from about 5% by weight of the cleaning compositions to about
99.9%, to about 80%, to about 35%, or even to about 30% by weight of the cleaning
compositions.
[0081] The compositions may include one or more detergent enzymes which provide
cleaning performance and/or fabric care benefits. Examples of suitable enzymes
include, but are not limited to, hemicellulases, peroxidases, proteases, other cellulases,
other xylanases, lipases, phospholipases, esterases, cutinases, pectinases,
keratanases, reductases, oxidases, phenoloxidases, lipoxygenases, ligninases,
pullulanases, tannases, pentosanases, malanases, [beta]-glucanases, arabinosidases,
hyaluronidase, chondroitinase, laccase, mannanase and amylases, or mixtures thereof.
A typical combination may comprise a mixture of enzymes such as protease, lipase,
cutinase and/or cellulase in conjunction with amylase.
[0082] Optionally, enzyme stabilisers may also be included amongst the cleaning
components. In this regard, enzymes for use in detergents may be stabilised by various
techniques, for example by the incorporation of water-soluble sources of calcium and/or
magnesium ions in the compositions.
[0083] The compositions may include one or more bleach compounds and associated
activators. Examples of such bleach compounds include, but are not limited to,
peroxygen compounds, including hydrogen peroxide, 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, ,'-
terephthaloyl-di(6-aminoperoxycaproic acid), ,'-phthaloylaminoperoxycaproic acid and
amidoperoxyacid. Bleach activators include, but are not limited to, carboxylic acid esters
such as tetraacetylethylenediamine and sodium nonanoyloxybenzene sulfonate.
[0084] Suitable builders may be included in the formulations 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 1,3,5-
tricarboxylic acid, carboxymethyloxysuccinic acid, and soluble salts thereof.
[0085] The compositions may also optionally contain one or more copper, iron and/or
manganese chelating agents and/or one or more dye transfer inhibiting agents.
[0086] Suitable polymeric dye transfer inhibiting agents include, but are not limited to,
polyvinylpyrrolidone polymers, polyamine N-oxide polymers, copolymers of Nvinylpyrrolidone
and N-vinylimidazole, polyvinyloxazolidones and polyvinylimidazoles or
mixtures thereof.
[0087] Optionally, the detergent formulations can also contain dispersants. Suitable
water-soluble 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.
[0088] Said anti-redeposition additives are physico-chemical in their action and include,
for example, materials such as polyethylene glycol, polyacrylates and carboxy methyl
cellulose.
[0089] Optionally, the compositions may also contain perfumes Suitable perfumes are
generally 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,6,6,9atetramethyl-
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.
[0090] Suitable optical brighteners 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 include, but are not limited to, 4,4'-
bis[[6-anilino-4(methylamino)-1 ,3,5-triazin-2-yl]amino]stilbene-2,2'-disulfonic 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'-disulfonic 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'-
stilbenedisulfonic acid, disodium salt, and 2,5-bis(benzoxazol-2-yl)thiophene.
[0091] Said agents may be used either alone or in any desired combination and may
be added to the cleaning system at appropriate stages during the cleaning cycle in order
to maximise their effects.
[0092] In any event, however, when the method of the invention is performed in the
presence of at least one additional cleaning agent, the quantity of said cleaning agent
required in order to achieve satisfactory cleaning performance is significantly reduced
from the quantities required with the methods of the prior art.
[0093] The ratio of solid particulate cleaning material to substrate is generally in the
range of from 0.1 : 1 to 10:1 w/w, typically in the region of from 0.5:1 to 5:1 w/w, with
particularly favourable results being achieved with a ratio of between 1: 1 and 3:1 w/w,
and especially at around 2:1 w/w. Thus, for example, for the cleaning of 5 g of fabric,
10 g of polymeric particles, optionally coated with surfactant, would be employed in one
embodiment of the invention. The ratio of solid particulate cleaning material to substrate
is maintained at a substantially constant level throughout the wash cycle.
[0094] The method of the present invention may be used for either small or large scale
batchwise processes and finds application in both domestic and industrial cleaning
processes.
[0095] As previously noted, the method of the invention finds particular application in
the cleaning of textile fabrics. The conditions employed in such a cleaning system do,
however, allow the use of surprisingly lower wash temperatures from those which
typically apply to the conventional wet cleaning of textile fabrics and, as a consequence,
offer significant environmental and economic benefits. Thus, typical procedures and
conditions for the wash cycle require that fabrics are generally treated according to the
method of the invention at, for example, temperatures of between 5 and 40^ for a
duration of between 5 and 45 minutes in a substantially sealed system. As an
approximate guide, it is found that if a conventional aqueous cleaning process requires a
wash temperature of T € , then the process according to the present invention will
provide superior cleaning at temperatures in the range of T-1 0°C to T-25°C. Thereafter,
additional time is required for the completion of the rinsing and bead separation stages
of the overall process, so that the total duration of the entire cycle is typically in the
region of 1 hour.
[0096] The results obtained are very much in line with those observed when carrying
out conventional wet (or dry) cleaning procedures with textile fabrics. The extent of
cleaning and stain removal achieved with fabrics treated by the method of the invention
is seen to be very good, with particularly outstanding results being achieved in respect of
hydrophobic stains and aqueous stains and soiling, which are often difficult to remove.
The energy requirement, the total volume of water used, and the detergent consumption
of the method of the invention are all significantly lower than those levels associated with
the use of conventional aqueous washing procedures, again offering significant
advantages in terms of cost and environmental benefits.
[0097] The method of the invention also shows benefits in terms of reducing washingrelated
fabric damage. As previously observed, fabric creasing readily occurs in
conventional aqueous washing, and this acts to concentrate the stresses from the
mechanical action of the wash at each crease, resulting in localised fabric damage.
Prevention of such fabric damage (or fabric care) is of primary concern to the domestic
consumer and industrial user. The addition of polymeric particles according to the
method of the invention provides effective cleaning but, at the same time, uniform and
gentle mechanical interaction with the fabric, thereby reducing fabric damage when
compared with conventional aqueous processes. It is, in particular, the uniformity of the
mechanical action generated by the chosen particles across the entire fabric surface that
is the key factor in this regard. The presence of the particles also effectively reduces
creasing in the wash by acting as a pinning layer on the fabric surface in order to help
prevent folding. The particles also inhibit interaction between separate pieces of fabric
in the wash by acting as a separation or spacing layer, thereby reducing entanglement.
Both folding and entanglement are major causes of localised fabric damage in
conventional aqueous processes. It is the localised aspect of the damage that
determines the lifetime of a garment under multiple washing.
[0098] Thus, the method of the present invention provides for enhanced cleaning
performance in comparison with the methods of the prior art at lower energy, water and
detergent conditions; alternatively, equivalent cleaning performance may be achieved at
even lower levels of all of energy water and detergent, together with reduced fabric
damage (see Examples). Removal of the beads from the fabric washload at the end of
the cleaning process is expedited on the basis of the specific size, shape and density of
the beads used, and also by control of process parameters, in order to enable bead re
use in subsequent cleaning processes.
[0099] In a specific preferred embodiment of the invention, a soiled substrate is placed
in a rotatably mounted cylindrical cage of 98 cm diameter and a detergent formulation
comprising surfactant and enzymes is added in combination with a small amount of
wash water art ambient temperature via a spray nozzle mounted on the door of the
apparatus. The cage is rotated at 40 rpm to give a G force of 0.88. Thereafter, the solid
particulate cleaning material, typically in the form of polymeric beads, is introduced into
said cage from said second chamber and the process, comprising continuous
recirculation of said material, is continued for 5-50 minutes. A further amount of wash
water containing bleach is added during this time at either ambient or elevated
temperature (in the former instance, the bleach is a low temperature activated
compound). Rotation is continued for several minutes after the bleach solution has been
added. Circulation is then discontinued in order to end the wash process.
[00100] The extraction stage of the cycle is then carried out in order to remove water
from the system, by rotating for about 2 minutes at a high G force of greater than 5.5;
preferably, said cage is rotated at about 600 rpm in order to generate a G force of
around 197.2. High speed rotation then ceases and a low G tumble (at around 40 rpm)
is carried out for approximately 5 minutes to remove the majority (> 50%) of the solid
particulate cleaning material remaining in the washload. Rinse water is then sprayed
into said cage via the nozzle for a few minutes, after which further rotation of the cage at
around 600 rpm takes place to remove the rinse water. The rinse process may be
repeated several times, generally up to 10 times, more preferably up to 5 times, typically
around 3 times. The rinse water which is added is not sufficient to submerge the fabric
in water, and is only used to the extent of resaturating the fabric ahead of the next
extraction stage. Optionally, fluorescent brighteners, perfumes, conditioners and the like
may be added during the course of the final spray rinse, following which the cage is
again rotated at low G (40 rpm) in order to allow for removal of the remaining solid
particulate cleaning material. The clean fabric may then be removed from the
apparatus.
[00101] Further, in a typical example of an operating cycle according to the method of
the invention, an initial addition of water and solid particulate cleaning material
(approximately 43 kg) is added to a washload of soiled substrate (15 kg) in a 98 cm
diameter rotatably mounted cylindrical cage, whilst rotating to generate 0.88 G (40 rpm).
Thereafter, further solid particulate cleaning material ( 10 kg) is pumped into said
rotatably mounted cylindrical cage via the separating means and control means
approximately every 30 seconds throughout the duration of the wash cycle which may
typically continue for around 30 minutes. The system is thereby designed to pump and
add solid particulate cleaning material at a sufficient rate to maintain roughly the same
level of solid particulate cleaning material in the rotatably mounted cylindrical cage
(about 2.9:1 by weight, for 43 kg of beads and 15 kg of fabric) throughout the wash.
[00102] Thus, during the wash cycle, the solid particulate cleaning material is continually
falling out of the rotatably mounted cylindrical cage through its perforations, and is being
recycled and added, together with fresh cleaning material, via the separating means and
control means. This process may either be controlled manually, or operated
automatically. The rate of exit of the solid particulate cleaning material from the
rotatably mounted cylindrical cage is essentially controlled by means of its specific
design. The key parameters in this regard include the size of the perforations, the
number of perforations, the arrangement of the perforations within the cage, and the G
force (or rotational speed) which is employed.
[00103] Generally, the perforations are sized at around 2-3 times the average particle
diameter of the solid particulate cleaning material which, in a typical example, results in
perforations having a diameter of no greater than 25.0 mm. In a preferred embodiment
of the invention, a rotatably mounted cylindrical cage would be drilled so that only around
34% of the surface area of the cylindrical walls of the cage comprises perforations.
Preferably, the perforations are banded in stripes or distributed evenly over the
cylindrical walls of the rotatably mounted cylindrical cage, but could be exclusively
located, for example, in one half of the cage.
[00104] The rate of exit of the solid particulate cleaning material from the rotatably
mounted cylindrical cage is also affected by the speed of rotation of said cage, with
higher rotation speeds increasing the G force, although at G > 1 the fabric adheres to
the sides of the cage and prevents exit of the cleaning material. Hence, slower
rotational speeds have been found to provide optimum results in this regard, as they
allow the beads to fall from the fabric and through the perforations as the fabric opens
out more during tumbling. Rotational speeds resulting in a G force of < 1 are therefore
required (10-42 rpm in a 98 cm diameter cage). The G force (or rotational speed) is also
controlled so as to maximise the beneficial effect of the mechanical action of the
cleaning material on the substrate, and the most suitable G is generally found to be in
the region of 0.9 G (40 rpm in a 98 cm diameter cage).
[00105] In addition, the moisture level in the wash also has an effect, with wetter
substrates tending to retain cleaning material for a longer time than drier substrates.
Consequently, overwetting of substrate can, if necessary, be employed in order to
further control the rate of exit of solid particulate cleaning material.
[00106] On completion of the wash cycle, addition of solid particulate cleaning material
to the rotatably mounted cylindrical cage is ceased, and the cage rpm is gradually
increased to give a G force of about 197.2 (600 rpm in a 98 cm diameter cylindrical
cage) for about 2 minutes in order to extract some liquid and dry the substrate to an
extent. High speed rotation then ceases and a low G tumble (at around 40 rpm) is
carried out for approximately 5 minutes to remove the majority (> 50%) of the solid
particulate cleaning material remaining in the washload. The rinsing cycles are then
carried out as hereinbefore described and the rotation G and rotational speed are finally
returned to the same values of < 1 and low (40) rpm as in the wash cycle in order to
complete the removal of cleaning material; this removal of beads generally takes around
20 minutes, as do each of the wash and rinse cycles in a typical operation, giving a total
overall cycle time in the region of 1 hour.
[00107] The method of the invention has been shown to be successful in the removal of
cleaning material from the cleaned substrate after processing and tests with polyester
beads, and nylon beads comprising either Nylon 6 or Nylon 6,6 polymer, have indicated
bead removal efficacy such that on average < 150 beads per washload remain at the
end of the bead separation cycle. Generally, this can be further reduced to an average
of < 40 beads per washload and, in optimised cases wherein a 20 minute separation
cycle is employed in combination with specific bead types, an average of < 5 beads per
washload can be achieved. With drier garments, achieved using higher G forces during
the water extraction stage of the process, this bead per garment figure can be even
further reduced.
[00108] Additionally, it has been demonstrated that re-utilisation of the polymer particles
in the manner described operates well, so that particles can be satisfactorily re-used in
the cleaning procedure, even though some deterioration in performance is generally
observed with recycled particles.
[00109] The invention will now be further illustrated, though without in any way limiting
the scope thereof, by reference to the following examples and associated illustrations.
Examples
Example 1 - Cleaning Performance
[001 10] Woven cotton fabric (194 gm~2 , Whaleys, Bradford, U.K.) was stained with
coffee, lipstick, ball point pen, tomato ketchup, boot polish, grass, vacuum dirt, curry
sauce and red wine following the methods described below:
(i) Coffee
10 g of Morrisons® Full Roast coffee powder was dissolved in 50 ml distilled water at
70 °C. A 1 cm3 aliquot of the ensuing solution was applied to the fabric using a synthetic
sponge, within the confines of a 5 cm diameter circular plastic template; the stained
fabric was then allowed to dry at ambient temperature (23 °C), after which the fabric was
aged prior to use, by storage in the dark for 4 days.
(ii) Lipstick
Revlon® Super Lustrous lipstick (copper frost shade) was applied to the fabric using a
synthetic sponge to provide a uniform coverage within the confines of a 5 cm diameter
circular plastic template. The fabric was then aged following the procedure recounted
for coffee.
(iii) Ball Point Pen
A black Paper Mate® Flex Grip Ultra ball point pen was used to uniformly cover the fabric
within the confines of a 5 cm diameter circular plastic template. The fabric was then
aged following the procedure recounted for coffee.
(iv) Tomato Ketchup
Heinz® tomato ketchup was applied to the fabric using a synthetic sponge to provide a
uniform coverage within the confines of a 5 cm diameter circular plastic template. The
fabric was then aged following the procedure recounted for coffee.
(v) Boot Polish
Kiwi® black boot polish was applied to the fabric using a synthetic sponge to provide a
uniform coverage within the confines of a 5 cm diameter circular plastic template. The
fabric was then aged following the procedure recounted for coffee.
(vi) Grass
Grass was collected manually from an MG7 (National Vegetation Classification) source.
10 g of the grass was chopped with scissors and blended with 200 ml of tap water using
an electronic blender. The mixture was then filtered using a metal sieve, and the filtrate
used as the staining medium. This was applied to the fabric using a synthetic sponge to
provide a uniform coverage within the confines of a 5 cm diameter circular plastic
template. The fabric was then aged following the procedure recounted for coffee.
(vii) Vacuum Dirt
Vacuum dirt was collected manually from a general domestic vacuum bag. 25 g of
vacuum dirt was mixed with 100 ml of tap water, and the mixture used to stain the fabric.
This was applied to the fabric using a synthetic sponge to provide a uniform coverage
within the confines of a 5 cm diameter circular plastic template. The fabric was then
aged following the procedure recounted for coffee.
(viii) Curry Sauce
Morrisons® own brand curry sauce was applied directly to the fabric using a synthetic
sponge to provide a uniform coverage within the confines of a 5 cm diameter circular
plastic template. The fabric was then aged following the procedure recounted for coffee.
(ix) Red Wine
"Spanish Red Wine" purchased at Morrisons® was applied directly to the fabric using a
synthetic sponge to provide a uniform coverage within the confines of a 5 cm diameter
circular plastic template. The fabric was then aged following the procedure recounted
for coffee.
[001 11] Each of the stains (i)-(ix) was applied to a single (36 cm x 30 cm) piece of
cotton fabric in the pattern described in Figure 1, to make up a standard stain set.
[001 12] Cleaning trials were then carried out using a set of trial and control conditions
(see Table 1) . Thus, the trials involved the use of a preferred apparatus as hereinbefore
defined according to the method of the invention ("Xeros" XP5), whilst control cleaning
trials were carried out using a standard domestic washing machine (Hotpoint Ultima
WT960 - XP6, XP7 and XP8). These control cleaning trials were carried out at different
temperatures using various levels of detergents (Unilever Persil® Small and Mighty
Biological - XP6 and XP7, or Procter & Gamble Ariel® Biological Liquid with Actilift -
XP8).
[001 13] The cleaning performance of the method of the invention at \ 5 ° (XP5) was
therefore compared to controls run in the domestic machine (Hotpoint Ultima WT960) at
the same temperature (XP6), and also at 40^ (XP7). An equivalent detergent dosage
was used in XP5, XP6 and XP7. As a further control the domestic wash was then
repeated at 40^, but this time with an alternative detergent at a much increased dosage
(Ariel® Biological Liquid with Actilift - XP8). This was chosen to provide the best
possible cleaning as a control (see Table 2 for detergent details and the recommended
dosage from the respective manufacturers).
[001 14] The domestic washes (XP6, XP7 and XP8) were carried out with 4 kg
washloads, even though the Hotpoint Ultima WT960 is rated as a 7 kg machine. This is
much more representative of the average washload size used in the European domestic
market, for example, and it in turn makes these controls more rigorous. The increased
free volume in the drum results in more mechanical action, and a better wash
performance.
TABLE 1 WASH TESTS
[001 15] The method according to the invention as hereinbefore described was carried
out using a preferred apparatus having a cylindrical cage of 98 cm diameter with 28.8
litres of wash water (i.e. 1.2 litres/kg washload) and 60 kg of INVISTA 110 1 polyester
beads (i.e. 2.5 kg/kg washload). No rinsing was employed.
TABLE 2 DETERGENT AND RECOMMENDED DOSAGE DETAILS
[001 16] The standard stain set of nine stains was used in all cases at 1 standard stain
set/kg of washload (see Figure 1) . These stains are representative of the range of
accidental stain types that can be encountered (enzymatic, oxidisable, greasy, and
particulate), and include grass, ketchup, coffee, red wine, ball point pen, curry sauce,
ground in dirt, lipstick and boot polish.
[001 17] In all cases XP5-XP8 a simulated sebum grease stain of 8 g/kg of washload
was incorporated into the test as impregnated cotton cloth (SBL-2004 from WFK). This
cloth, which starts out a dark grey in colour (Figure 1) , is used to better simulate the
domestic washing environment where such collar and cuff grease is the dominant stain
(making up some 80 % of the overall stain loading). Sebum is derived from the skin's
sebaceous glands.
[001 18] The wash test results are illustrated in the accompanying Figures as follows:
Figure 2 (XP5), Figure 3 (XP6), Figure 4 (XP7), Figure 5 (XP8), Figure 6 (XP5 versus
XP6), and Figure 7 (XP5 versus XP7).
[001 19] As can be seen from Figures 2, 3 and 6, there is a marked improvement in
cleaning performance with the method of the invention when compared to the domestic
equivalent at 15°C wash temperature. All nine of the standard set of stains have
cleaned to a greater extent, and in particular the sebum cloth has lightened appreciably
in colour. This last observation should not be underestimated, particularly as it could
represent a significant enhancement in low temperature grease removal, which has long
been a goal of the laundry industry.
[00120] Figures 2, 4 and 7 show that there is at least parity cleaning of all nine standard
stains and the sebum cloth for the low temperature wash according to the method of the
invention, even compared to the domestic control run at 40°C. This is a very significant
potential upside for power saving, and shows the enhancement from bead mechanical
action with the method of the invention, which a conventional wash obviously cannot
match. Comparison of Figures 2 and 5 shows that the same conclusion can be drawn
again against a domestic control at 40^ but here with a significantly higher still
detergent dosage/kg.
Example 2 - Fabric Care
[00121] Tests were carried out in order to illustrate the reduced localised fabric damage
associated with the method of the present invention. Thus, Figures 8 and 9 show the
result of washing a specially manufactured cloth sample (EMPA #306 test cloth: "Polka-
Dot Type A (low-mid)), which is designed to highlight the effects of mechanical action in
the washing process. Figure 8 is a sample of this cloth after a wash in a preferred
apparatus as hereinbefore defined according to the method of the invention, and Figure
9 is a sample of this cloth after a wash in a conventional domestic washing machine.
[00122] The domestic wash was carried out in a BEKO WM5120W machine, on a 40 €
cotton wash cycle at a 1200 rpm spin speed setting, using 4 kg of cotton ballast and 1
EMPA #306 cloth. The detergent used was 80 g of Procter & Gamble Ariel® biological
powder (i.e. 20 g/kg) which is the manufacturer's recommended dosage. The process
according to the invention was carried out in a preferred apparatus (98 cm cage
diameter) with a 24 kg mixed fabric washload, 28.8 litres of wash water (i.e. 1.2 litres/kg
washload) and 60 kg of INVISTA 1101 polyester beads (i.e. 2.5 kg/kg washload). The
detergent was also Procter & Gamble Ariel® biological powder, but only 192 g (i.e. 8
g/kg) was used - which is 40% of the manufacturer's recommended dosage. A threerinse
process was employed at 300 rpm spin speed.
[00123] In this instance, Figure 9 (BEKO - prior art) shows the removal of the rubber
dots adhering to the EMPA #306 cloth surface resulting in an irregular pattern and, in
particular, the effects of folding and creasing can be seen, with highly concentrated
removal streaks. These can be readily associated with high levels of localised fabric
damage. Figure 8 (method of the invention) shows a totally different removal pattern
resulting in an overall higher level of removal but, critically, this is much more uniform.
Hence, there is likely to be better cleaning (as shown in other examples here), but
significantly less localised fabric damage. It is the localised aspect of the damage that
determines the lifetime of a garment under multiple washing, and garment lifetime is
obviously a primary benefit to the consumer.
[00124] As a comparative illustration, Figure 10 shows an unwashed sample of the
EMPA #306 cloth.
Example 3 - Cleaning Performance
[00125] Energy, water and detergent consumption values were determined for the
method of the presently claimed invention when using the preferred apparatus (98 cm
diameter cage) and compared with values achieved with a Miele PW 6241 EL
commercial machine. The results are shown in Table 3. The Miele PW 6241 EL
conventional tests were carried out with 12 kg washloads, even though this machine is
rated as a 24 kg machine. This was again to make these controls more rigorous, as the
increased free volume in the drum results in more mechanical action, and a better wash
performance. The detergent used was Procter & Gamble Professional Ariel® Liquid at
the manufacturer's recommended dosage of 30 ml/kg. Wash temperatures of 40^ and
60 ° were used (controls ML1 and ML2 respectively). The washload contained 3
professional commercial laundry stain monitors (PCMS-55_05-05x05 from WFK - see
Figures 11(a) and 11(b)), 12 sebum cloths (SBL-2004 from WFK), with the remaining
washload made up with cotton ballast.
[00126] Cotton ballast was also used to make up the washloads for the cleaning tests
according to the current invention, but here the washload was 16 kg, containing 3
PCMS-55_05-05x05 stain monitors, and 16 SBL-2004 sebum cloths. The so-called
"Xeros Standard" method according to the invention was carried out at 40^ (74 litres of
wash water, i.e. 4.6 litres/kg of washload), and the "Xeros Ambient" method according to
the invention, was carried out at \ 5 ° (28 litres of wash water - i.e. 1.75 litres/kg
washload). In each case a three rinse process using 90 litres of water in total was
employed, and the bead used was 50 kg of INVISTA 110 1 polyester (i.e. 3.1 kg/kg
washload). The same detergent was used as with the ML1 and ML2 controls, but now at
significantly reduced levels (14.1 ml/kg for "Xeros Ambient" and 18.8 ml/kg for "Xeros
Standard"). Examination of the cleaned stain monitors showed that the "Xeros Ambient"
process produced superior cleaning performance to the ML1 control (see Figures 12 and
13), and the "Xeros Standard" was even more impressive when compared to the ML2
control (see Figures 14 and 15). The savings in energy, water and detergent
consumption with "Xeros Ambient" versus ML1 and "Xeros Standard" versus ML2 are
evident from Table 3.
TABLE 3 WASH TESTS
Example 4 - Cleaning Performance
[00127] Energy, water and detergent consumption values were determined for the
method of the presently claimed invention when using the preferred apparatus (98 cm
diameter cage) and compared with the values ascribed to A class performance in
domestic washing, namely: an energy consumption of < 0.19 kWh/kg, a water usage of
< 9.7 litres/kg, and a detergent dosage of approximately 8.0 g/kg (8.5 ml/kg) - see Table
4. Parity cleaning to a 60°C wash cycle was achieved using the current invention for a
25 kg washload including 5 WFK PCMS-55_05-05x05 professional laundry stain
monitors and 25 SBL-2004 sebum cloths, made up to load size with cotton ballast.
[00128] The "Xeros Ambient" method according to the invention was carried out at \ 5 °
as in Example 3 (i.e. 28 litres wash water, equivalent in this case to 1.12 litres/kg
washload), and "Xeros Standard" at 40^ also as in Example 3 (i.e. 74 litres wash water,
equivalent in this case to 2.96 litres/kg). In each instance a three rinse process using 90
litres of water in total was again employed, and the bead used was, once more, INVISTA
110 1 polyester (50 kg, i.e. 2.0 kg/kg washload). The detergent dosage level, however,
was reduced to 7.0 ml/kg (6.6 g/kg) for both processes (Procter & Gamble Professional
Ariel® Liquid). It should be noted that only parity cleaning to a 60 ° wash cycle was
achieved in this instance, and so the superior cleaning performance achieved by both
processes in Example 3 was effectively sacrificed in order to increase the washload size
and lower the detergent dosage. The "Xeros Standard" process at 40^ did slightly
outperform the "Xeros Ambient" process at \ 5 ° , however, as would be expected.
TABLE 4 WASH TESTS
Example 5 - Bead Removal from the Washload
[00129] The effects of bead size, shape and density on bead trapping in a washload
were tested by individually tumbling 10 kg of various different bead types at G < 1 in a
sealed drum (50 cm diameter) with 15 dress shirts. The shirts were uniformly wetted
with 6 litres of water, and tumbling was carried out at ambient temperature for 30
minutes. The same shirts were dried and re-used for each test. A comparison was then
made of the number of beads retained in the shirt pockets, collar bone inserts and
button seams in each case. The beads used were as detailed in Table 5 and Figure 16.
The results can be seen in Table 6.
TABLE 5 BEAD TYPES
TABLE 6 BEAD RETENTION IN SHIRTS
[00130] It should be noted that the number of beads retained here is high, and not
representative of the invention currently claimed. This is due to the fact that the drum
used in these tests was sealed (i.e. no sidewall perforations), and hence the beads were
effectively being forced into the shirts. The results are still indicative however, of the
effects of bead size, shape and density on bead retention and, hence, offer an indication
of likely bead removal levels in the current invention.
[00131] It can be seen by comparison of the 1101 and 24BS bead retention levels that
beads with similar size and shape can be retained to different extents, and that bead
density is a key factor in determining retention levels. Higher density beads are less
retained and, hence, more likely to be removed in any cleaning process involving
polymeric beads.
[00132] From a comparison of the 24BS and the 24BL bead retention levels, it is evident
that beads of a similar density can also be retained to different extents, and that bead
size is another key factor in determining retention levels for a particular bead shape.
Larger beads of the same shape are less retained (24BL is 3 times the volume of 24BS)
and, thus, more likely to be removed in any process involving polymeric beads.
[00133] It is also observed from a comparison of the 110 1 , 24BS and 575P bead
retention levels that bead size can overcome low bead density, to reduce retention
levels. Thus, the very low density 575P bead is less retained than the more dense 24BS
as it is 4 times the volume of 24BS, but it is still more retained than the denser 1101 in
comparison to which it is also 4 times larger.
[00134] The move to a still larger bead is therefore perceived to be desirable, and the
benefit of this course of action is illustrated by the 101 bead retention level. In this case
retention has been effectively eliminated by the move to a much larger bead ( 10 1 is
more than 10 times the volume of 1101 and 24BS, 3.5 times the volume of 24BL, and
2.5 times the volume of 575P). This result is a clear indication of the effect of size,
despite the change of shape from cylindrical to a perfect sphere.
5 [00135] To further emphasise these results, "Xeros Ambient" and "Xeros Standard"
wash cycles were run in apparatus as described in WO-A-201 1/098815 (98 cm diameter
cage). Various 16-25 kg washloads were used as part of a series of trials conducted at
commercial laundries in London, UK, for bead 1101 , 334 and 335 (see Table 7). Bead
101 was tested separately by Xeros Ltd in Sheffield, UK. Water consumption levels
10 were as described in Examples 3 and 4 ( 1 18 litres for "Xeros Ambeint", and 164 litres for
"Xeros Standard"). The wash temperatures employed were: "Xeros Ambient" at \ 5 ° ,
and "Xeros Standard" at 40°, 60° or 65°C, depending on the exact washload used.
Detergency was also varied across the different washload types. Table 7 therefore
shows the average separation achieved over the washloads tested (some 100 runs in
15 total), and the relative cleaning performance observed for these different bead types.
TABLE 7 SELECTED BEADS AND THEIR ATTRIBUTES
[00136] Hence, if as close to complete separation of the bead from the washload as
possible is required, then bead 10 1 would appear to offer the best option. The 50 kg of
beads used for a 25 kg washload (i.e. 2.0:1 kg/kg washload) showed only 3 beads
retained, or 99.999% bead removal. The compromise, however, is that fewer beads and
less mechanical action (due to their perfectly spherical shape), results in some reduction
in cleaning performance (see Table 7). For less heavily soiled washloads, however, this
may not be a problem and, hence, these beads are still comprised in a preferred
embodiment of the current invention.
[00137] In the event that the washload is more heavily soiled, then a move to a smaller,
spherical bead (not a perfect sphere) may be preferred (coded 334 and 335 in Table 7).
In this case, the separation is still acceptable (bead 334: 50 kg of beads used for a 25 kg
washload gave 20 beads retained or 99.999% removal; bead 335: 50 kg of beads used
for a 25 kg washload gave 35 beads retained or 99.999% removal), but the cleaning
performance is increased (more beads/kg added than with bead 101 , and with a rougher
surface to generate more mechanical action). Hence, these too are included as a
preferred embodiment of the current invention, and they are perhaps the best
compromise between cleaning performance and separation from the washload.
[00138] Finally, if the washload is very heavily soiled, the use of an even smaller
cylindrical bead, such as bead 1101 , may be preferred (again, see Table 7), as this still
further increases cleaning performance (more beads/kg added than with beads 334 or
335, and with well-defined edges to their shape, to generate even more mechanical
action). Here, the separation performance does, however, fall slightly: 50 kg of beads
used for a 25 kg washload gave 142 beads retained or 99.996% removal. Such beads,
therefore, are also comprised in a further embodiment of the invention.
[00139] It should be emphasised that the bead selections in Table 7 are not
comprehensive, and different balances of bead size, shape and density will affect the
cleaning and separation performance of the polymeric particles used. Different choices
to those made above within the ranges of bead size, shape and density claimed here
could prove equally effective.
[00140] 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.
[00141] 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.
[00142] 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. A method for the cleaning of a soiled substrate, said method comprising
treating the substrate with a solid particulate cleaning material and wash water, said
treatment being carried out in an apparatus comprising a drum comprising perforated
side walls and having a capacity of between 5 and 50 litres for each kg of fabric in the
washload, wherein said solid particulate cleaning material comprises a multiplicity of
polymeric particles at a particle to fabric addition level of 0.1 :1-10:1 by mass, each
particle being substantially cylindrical or spherical in shape and having an average
density in the range of 0.5-2.5 g/cm3 and an average volume in the range of 5-275 mm3,
and wherein said drum comprising perforated side walls is rotated at a speed which
generates G forces in the range of from 0.05 to 900 G.
2. A method as claimed in claim 1 wherein said drum comprising perforated side
walls comprises a rotatably mounted cylindrical cage.
3. A method as claimed in claim 1 or 2 wherein the solid particulate cleaning
material is separated and recovered and then re-used in subsequent cleaning
processes.
4. A method as claimed in claim 1, 2 or 3 wherein the solid particulate cleaning
material is cleaned intermittently in order to maintain its efficacy.
5. A method as claimed in any one of claims 1 to 4 wherein said temperatures do
not exceed 75°C.
6. A method as claimed in claim 5 wherein said temperature is in the range of
from 5-40 € .
7. A method as claimed in any one of claims 1 to 6 wherein said polymeric
particles comprise foamed or unfoamed polymeric materials.
8. A method as claimed in any preceding claim wherein said polymeric particles
comprise linear or crosslinked polymers.
9. A method as claimed in any preceding claim wherein said polymeric particles
comprise beads of polyalkenes, polyamides, polyesters or polyurethanes.
10. A method as claimed in claim 9 wherein said polyamide comprises Nylon 6 or
Nylon 6,6.
11. A method as claimed in claim 10 wherein said polyamide comprises Nylon 6,6
homopolymer having a molecular weight in the region of from 5000 to 30000 Daltons.
12. A method as claimed in claim 9 wherein said polyester comprises polyethylene
terephthalate or polybutylene terephthalate.
13. A method as claimed in any preceding claim wherein said polymeric particles
comprise monomeric units derived from monomers which comprise ionically charged or
polar moieties, or unsaturated organic groups.
14. A method as claimed in claim 13 wherein said monomers comprise acid or
amino groups or salts thereof, or pendant alkenyl groups.
15. A method as claimed in any preceding claim wherein said multiplicity of
polymeric particles comprises cylindrical particles of oval cross section having a major
cross section axis length of 2.0-6.0 mm.
16. A method as claimed in claim 15 wherein said particles have a minor cross
section axis length of 1.3-5.0 mm.
17. A method as claimed in claim 15 or 16 wherein said particles have a length of
1.5-6.0 mm.
18. A method as claimed in any one of claims 1 to 14 wherein said multiplicity of
polymeric particles comprises cylindrical particles of circular cross section having a
diameter of 1.3-6.0 mm.
19. A method as claimed in claim 18 wherein said particles have a length of 1.5-6.0
mm.
20. A method as claimed in any one of claims 1 to 14 wherein said multiplicity of
polymeric particles comprises spherical particles having a diameter of 2.0-8.0 mm.
2 1 . A method as claimed in claim 20 wherein said particles comprise perfect
spheres.
22. A method as claimed in any one of claims 2 to 2 1 wherein said rotatably
mounted cylindrical cage is comprised in a cleaning apparatus comprising a housing and
access means, allowing access to the interior of said cylindrical cage.
23. A method as claimed in any one of claims 2 to 22 wherein said rotatably
mounted cylindrical cage is concentrically located within a rotatably mounted cylindrical
drum having a greater diameter than said cage, wherein said cage and said drum are
concentrically located within a stationary cylindrical drum having a greater diameter than
said rotatably mounted drum, and wherein said rotatably mounted cylindrical cage and
said rotatably mounted cylindrical drum are adapted to rotate independently.
24. A method as claimed in any one of claims 2 to 23 wherein said rotatably
mounted cylindrical cage is mounted in a first chamber within said housing means, which
also comprises a second chamber located adjacent said cylindrical cage.
25. A method as claimed in claim 24 which additionally comprises at least one
recirculation means and a multiplicity of delivery means.
26. A method as claimed in claim 24 or 25 which additionally comprises sealing
means, removably attached to the outer surface of the cylindrical side walls of said
rotatably mounted cylindrical cage, and adapted to prevent the ingress or egress of
fluids and solid particulate matter from the interior of said cage.
27. A method as claimed in claim 24 or 25 which additionally comprises pumping
means, and wherein up to 60% of the surface area of the perforated side walls of said
rotatably mounted cylindrical cage comprises perforations, and said perforations
comprise holes having a diameter of no greater than 25.0 mm.
28. A method as claimed in any one of claims 22 to 27 wherein said access means
comprises a hinged door mounted in the housing which may be opened to allow access
to the inside of the cylindrical cage and which may be closed in order to provide a
substantially sealed system.
29. A method as claimed in any one of claims 2 to 28 wherein said apparatus
comprises circulation means, adapted to promote circulation of said solid particulate
cleaning material.
30. A method as claimed in any one of claims 2 to 29 wherein said rotatably
mounted cylindrical cage comprises a 98 cm diameter cage and the speeds of rotation
are in the range of 10-800 rpm.
3 1 . A method as claimed in any preceding claim which comprises performing,
sequence, the steps of:
(a) washing;
(b) first extraction of wash water;
(c) first separation of polymeric particles;
(d) rinsing;
(e) second extraction of excess water;
(f) optionally repeating steps (d) and (e) at least once; and
second separation of polymeric particles.
32. A method as claimed in claim 3 1 wherein steps (d) and (e) are repeated up to
10 times.
33. A method as claimed in claim 3 1 or 32 wherein said washing process is carried
out at between 0.05 and 0.95 G, the rinsing water is added under similar conditions, then
extracted at a higher G force of 5.5 to 350 G, and said separation of beads from the
fabric is carried out at 0.05 to 0.95 G.
34. A method as claimed in claim 33 wherein said drum comprising perforated side
walls comprises a rotatably mounted cylindrical cage having a diameter of 98 cm, said
washing process is carried out at a speed of rotation of between 10 and 42 rpm, the
rinsing water is added under similar conditions, then extracted at a speed of rotation of
100-800 rpm, and said separation of the beads from the fabric is carried out at a speed
of rotation of 10-42 rpm.
35. A method as claimed in any one of claims 2 to 34 wherein a wash cycle
comprises the steps of:
(i) introducing a solid particulate cleaning material and water into a
second chamber of an apparatus as hereinbefore described;
(ii) agitating said solid particulate cleaning material and water;
(iii) loading at least one soiled substrate into said rotatably mounted
cylindrical cage via access means;
(iv) closing the access means so as to provide a substantially sealed
system;
(v) causing the rotatbly mounted cylindrical cage to rotate whilst
introducing said wash water and any required additional cleaning
agent to uniformly wet out the substrate;
(vi) introducing said solid particulate cleaning material into said
rotatably mounted cylindrical cage, and operating the apparatus
for a wash cycle, wherein said rotatably mounted cylindrical cage
continues to rotate, and wherein fluids and solid particulate
cleaning material are caused to fall through perforations in said
rotatably mounted cylindrical cage into said second chamber in a
controlled manner;
operating pumping means so as to transfer fresh solid particulate
cleaning material and recycle used solid particulate cleaning
material to separating means;
operating control means so as to add said fresh and recycled
solid particulate cleaning material to said rotatably mounted
cylindrical cage in a controlled manner; and
continuing with steps (vi), (vii) and (viii) as required to effect
cleaning of the soiled substrate.
36. A method as claimed in any preceding claim wherein at least one additional
cleaning agent is employed.
37. A method as claimed in claim 36 wherein said at least one additional cleaning
agent is pre-mixed with water and added to said drum comprising perforated side walls
via separating means during the introduction of said solid particulate cleaning material
and water into said drum comprising perforated side walls via recirculating means.
38. A method as claimed in claim 36 wherein said at least one additional cleaning
agent is added to said drum comprising perforated side walls via dosing means.
39. A method as claimed in claim 38 wherein said dosing means comprises a
fixedly mounted spray nozzle optionally mounted on an access means.
40. A method as claimed in any one of claims 36 to 39 wherein said at least one
additional cleaning agent may be added to said drum comprising perforated side walls in
multiple dosing steps during the cleaning operation.
4 1. A method as claimed in any one of claims 36 to 40 wherein said at least one
additional cleaning agent comprises a detergent composition comprising cleaning
components and post-treatment components.
42. A method as claimed in claim 4 1 wherein said cleaning components are
selected from surfactants, enzymes and bleach.
43. A method as claimed in claim 4 1 or 42 wherein said post-treatment components
are selected from components anti-redeposition additives, perfumes and optical
brighteners.
44. A method as claimed in claim 4 1, 42 or 43 which comprises one or more other
additives selected from builders, chelating agents, dye transfer inhibiting agents,
dispersants, enzyme stabilizers, catalytic materials, bleach activators, polymeric
dispersing agents, clay soil removal agents, suds suppressors, dyes, structure
elasticizing agents, fabric softeners, starches, carriers, hydrotropes, processing aids and
pigments.
45. A method as claimed in any one of claims 3 1 to 44 which additionally comprises
the addition of treatment agents to the rinse water.
46. A method as claimed in claim 45 wherein said treatment agents are selected
from at least one of fluorescent brighteners, perfumes, softeners and starch.
47. A method as claimed in any preceding claim which is carried out at a wash
water to substrate ratio of between 5.0:1 and 0.1 : 1 w/w.
48. A method as claimed in any preceding claim for use in small or large scale
batchwise processes.
49. A cleaning composition comprising a solid particulate cleaning composition and
at least one additional cleaning agent, wherein said solid particulate cleaning material
comprises a multiplicity of polymeric particles.
50. A cleaning composition as claimed in claim 49 wherein said at least one
additional cleaning agent comprises at least one detergent composition.
5 1 . A cleaning composition as claimed in claim 49 or 50 wherein said polymeric
particles comprise foamed or unfoamed polymeric materials.
52. A cleaning composition as claimed in any one of claims 49 to 5 1 wherein said
polymeric particles comprise linear or crosslinked polymers.
53. A cleaning composition as claimed in any one of claims 49 to 52 wherein said
polymeric particles comprise beads of polyalkenes, polyamides, polyesters or
polyurethanes.
54. A cleaning composition as claimed in claim 53 wherein said polyamide
comprises Nylon 6 or Nylon 6,6.
55. A cleaning composition as claimed in claim 53 wherein said polyester
comprises polyethylene terephthalate or polybutylene terephthalate.
56. A cleaning composition as claimed in any one of claims 49 to 55 wherein said
polymeric particles comprise monomeric units derived from monomers which comprise
ionically charged or polar moieties, or unsaturated organic groups.
57. A cleaning composition as claimed in any one of claims 49 to 56 wherein said
monomers comprise acid or amino groups or salts thereof, or pendant alkenyl groups.