Manufacture and use of a composite material comprising fibres and at least
one vinyl chloride polymer
This application claims priority to French application No. 1153 150 filed on
11 April 201 1 and of French application No 1160168 filed on 8 November 201 1,
the whole content of these applications being incorporated herein by reference
for all purposes.
The present invention relates to a process for manufacturing a composite
material comprising fibres and at least one vinyl chloride polymer. It also relates
to this composite material itself. It further relates to the use of this composite
material for forming articles or for manufacturing reinforced objects and also to
these articles or reinforced objects themselves and reinforced profiles.
Many joinery elements such as frames, framework, jambs and transoms of
windows, shutters, doors and gates are frequently formed based on PVC
(polyvinyl chloride), which gives them durability, corrosion resistance and
thermal insulating properties, while requiring only a minimum amount of
maintenance. However, they lack rigidity from certain dimensions onwards.
Indeed, the PVC profiles used for the construction of these j oinery
elements are generally hollow in order to lighten them and create chambers that
have a thermal insulation role. However, one problem inherent to PVC is its low
elastic modulus and therefore its deformability under strain, especially when the
spans between fixed points are large.
The lack of rigidity may be overcome by reinforcing the frames with metal
reinforcements and especially steel (see document DE 199 33 099) or aluminium
reinforcements. However, the use of metal reinforcements creates thermal
bridges within the profiles of the frame leading to significant heat losses via the
increase of the thermal conductivity. Furthermore, the presence of these metal
reinforcements complicates the end-of-life recycling of the profiles.
In order to counteract this increase of the thermal conductivity, it has been
proposed to use reinforcements (pultruded inserts) constituted of thermosetting
resins with fibres, preferably continuous fibres, of glass, aramid or carbon
(documents GB 2 144 472 or EP 0 441 449). However, the use of thermosetting
resins with glass fibres is expensive. As regards the thermoplastic composite
materials reinforced by cellulose fibres described in document US 2004/062915,
they are much more moisture-sensitive and therefore less durable.
Conventionally, PVC profiles reinforced by introduction of a metal insert
or of a pultruded insert are not recyclable or are difficult to recycle. Another
disadvantage of profiles reinforced by a pultruded insert is the fact that it is
necessary, just like for metal reinforcements, to manually introduce the
reinforcement, which increases their production cost.
Described in document EP 1 276 602 are joinery elements comprising a
PVC profile reinforced by at least one reinforcing tape composed of fibres made
of polyester, in particular made of PET (polyethylene terephthalate) or of PBT
(polybutylene terephthalate) commingled with continuous glass fibres; the
polymer fibres and glass fibres being arranged in a longitudinal and parallel
manner. The tapes of fibres, or rovings, are heated in order to melt the polymer,
pressed and finally embedded in the outer and opposite walls of the final PVC
profile to provide sufficient rigidity and thus avoid the use of metal or pultruded
inserts. Even though high mechanical properties are obtained and the manual
insertion of the metal or pultruded profile is avoided owing to the manufacturing
process which uses reels that make it possible to unwind continuous yarns
comprising continuous filaments of glass and of a thermoplastic commingled
together, this process has many disadvantages. One of the drawbacks of this
system is combining two different thermoplastics that are incompatible in the
melt state, a polyester such as PET or PBT on the one hand and PVC on the
other hand, in the final product, making not only the recycling of the profile
difficult, but also making the recycling of the production scrap and also of the
blanks impossible in the production line of the profiles. Another drawback is the
longitudinal brittleness of the reinforcements which preferably break along the
fibres during a multiaxial impact. Finally, one major drawback is the difficulty
in calibrating the profile when it is cooling considering that the PVC and the
reinforcing tape have different thermal expansion coefficients.
In document EP 0 179 688, it has been proposed to subject reinforcing
elements (especially glass fibres) for composite materials to an electrostatic field
induced by a very high voltage electric current, then to impregnate them with a
liquid matrix material (or liquid precursor of the material), while they are still
under the influence of the field. The very high voltages that must be used in
order to carry out this process are not without danger for the operators and
require a lot of electrical energy; it is not easy either to correctly synchronize the
swelling of the reinforcing fibres under the action of the electrostatic field and
their impregnation by the liquid matrix material.
The present invention aims to solve these problems by providing a process
for manufacturing an easily recyclable composite material that can be formed
into articles of higher rigidity and that can, in addition, be easily used according
to conventional methods and especially by pultrusion, especially for producing
reinforced objects.
For this purpose, the main subject of the invention is a process for
manufacturing a composite material comprising fibres and at least one vinyl
chloride polymer comprising the immersion of the fibres in a hydrosol of said
polymer in order to obtain fibres coated with said hydrosol followed by the
drying and gelling of said hydrosol coated on the fibres.
The expression "composite material" is understood in the present
description to mean a solid material comprising at least two components that are
immiscible, but that have a high adhesion capacity; one of the components of this
material being constituted of fibres that provide the mechanical strength; the
other constituent, conventionally known as the "matrix", being the vinyl chloride
polymer(s) that ensure(s) the cohesion of the structure and the retransmission of
the stresses to the fibres.
The term "fibres" is understood to mean, in the present description, any
elementary (or unitary) fibre (also known as a "filament") and also any assembly
of elementary fibres.
Examples of an assembly of elementary fibres are woven fabrics (i.e. an
assembly where the elementary fibres are arranged, for one part, in the length
direction and, for the other part, in the width direction), nonwoven fabrics also
referred to as "mats" (i.e. an assembly where the elementary fibres are arranged
randomly in one main plane) and "rovings" (i.e. an untwisted assembly of several
elementary fibres).
Advantageously, one of the characteristic dimensions ("length") of these
fibres is considerably larger than the other ("diameter" in the case of the
filament) or at least than one of the two others ("thickness" and "width" in the
case of an assembly of elementary fibres). In the case where one of the
components of the composite material according to the invention is an assembly
of elementary fibres, their length is preferably considerably larger than both their
thickness and their width.
The expression "considerably larger" should be understood to mean more
than 10 times larger, preferably more than 25 times larger, more preferably still
more than 100 times larger and very particularly preferably more than 500 times
larger. According to another term, the fibres according to the invention may be
referred to as continuous fibres.
Preferably, the fibres are an assembly of elementary fibres, particularly
preferably they are an assembly of elementary fibres chosen from woven fabrics,
nonwoven fabrics and rovings.
In this preferred case, the assembly may or may not be ordered and may or
may not be regular. The elementary fibres may be arranged in the assembly:
- in an ordered manner and be entangled, as in the case of woven fabrics;
- in a disordered manner and be entangled, as in the case of nonwoven fabrics
or "mats", or
- in an unentangled manner, longitudinally and parallel to one another, as in the
case of "rovings".
Very particularly preferably, the fibres are an assembly of elementary
fibres chosen from woven fabrics and "rovings", with a very particular
preference for rovings.
In this case, the elementary fibres of the assembly are therefore
advantageously arranged in an unentangled manner, longitudinally and parallel
to one another.
The fibres that can be used according to the invention may be any
commercially available fibres. They may be organic fibres, mineral fibres,
mixtures of organic fibres and mineral fibres, mixtures of various organic fibres
with one another and mixtures of various mineral fibres with one another.
Mention may be made, as examples of organic fibres, of the fibres derived
from natural products, of plant or animal origin, such as hemp, flax, cotton, wood
and silk for example, or from synthetic products such as polymeric fibres.
Mention may be made, as examples of mineral fibres, of asbestos fibres,
glass fibres, metallic fibres and basalt fibres for example.
According to a first alternative, the fibres are fibres resulting from products
of plant origin chosen from hemp and flax.
According to a second alternative, the fibres are mineral fibres chosen from
glass fibres and basalt fibres.
Very good results have been recorded when the fibres are rovings of flax
fibres, rovings of glass fibres or rovings of basalt fibres.
The fibres that can be used according to the invention may have been
coated with a coupling agent during their manufacturing cycle, thus improving
the homogeneity of their subsequent impregnation by the hydrosol of vinyl
chloride polymer and the mechanical properties of the composite material.
Among the coupling agents customarily used, mention may be made, nonexhaustively,
of silanes, polyesters, acrylic or methacrylic polymers, waxes and
epoxides. Among these, silanes are preferred. As examples, mention may
especially be made of 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane
and also derivatives thereof such as gamma-methacryloxypropyltrimethoxysilane,
N-benzyl-N-aminoethyl-3-aminopropyltrimethoxysilane and
the corresponding hydrochloride, N-phenyl-3-aminopropyltrimethoxysilane and
N-2-(vinylbenzylamino)ethyl-3-aminopropyltrimethoxysilane.
The composite material manufactured according to the invention may be
flexible (and therefore can be wound) or may be more or less rigid.
As for the fibres, one of the characteristic dimensions ("length") of the
composite material manufactured according to the invention is considerably
larger than the other ("diameter" in the case of a filament) or at least than one of
the two others ("thickness" and "width" in the case of an assembly of elementary
fibres). In the preferred case where the composite material comprises an
assembly of elementary fibres, the length of the composite material is
considerably larger than both its thickness and its width.
The expression "considerably larger" has the same meaning as when used
above in connection with the fibres.
The composite material manufactured according to the invention comprises
at least one vinyl chloride polymer. In the present description, the expression
"vinyl chloride polymer" or more briefly, "polymer" is understood to mean all
polymers containing at least around 50% by weight, preferably at least 60% by
weight, particularly preferably at least 70% by weight and very particularly
preferably at least 85% by weight of monomer units derived from vinyl chloride,
therefore both vinyl chloride homopolymers (containing 100% by weight of
monomer units derived from vinyl chloride) and copolymers of vinyl chloride
with vinyl esters such as vinyl acetate. Among the vinyl chloride polymers
mentioned above, preference is accorded to vinyl chloride homopolymers and to
copolymers of vinyl chloride with vinyl acetate, with a particular preference to
vinyl chloride homopolymers. The vinyl chloride polymer is therefore preferably
a homopolymer.
Use is advantageously made, within the context of the invention, of vinyl
chloride polymers, preferably vinyl chloride homopolymers, having a melt flow
index or K-value (conventionally known as Kw or K-wert), measured according
to the standard ISO 1628 - 2, of greater than 55, preferably greater than 60. This
K-value is advantageously less than 85, preferably less than 80. For practical
reasons (commercial availability), use if very particularly preferably made of
polymers having a K-value between 65 and 75.
In the present description, the expression "at least one vinyl chloride
polymer" means that the composite material may contain a single polymer or
several polymers of vinyl chloride. The term "polymer" is used indiscriminately
in the singular and in the plural in the present description.
In the case where the composite material may contain several vinyl
chloride polymers, these may be mixtures of homopolymers having different
melt flow indexes, mixtures of homopolymers and of copolymers or else
mixtures of copolymers having different monomer compositions with one
another. Preferably, the composite material comprises a single vinyl chloride
polymer that is particularly preferably a vinyl chloride homopolymer.
The process according to the invention comprises the immersion of the
fibres in a hydrosol of the vinyl chloride polymer.
In the present description, the term "hydrosol" is understood to mean a
fluid and colloidal system in which the dispersed phase comprises the vinyl
chloride polymer and in which the continuous phase is water.
The hydrosol of the vinyl chloride polymer is advantageously obtained by
radical polymerization in aqueous emulsion.
The expression "radical polymerization in aqueous emulsion" is
understood in the present description to mean any radical polymerization process
that takes place in an aqueous medium in the presence of emulsifiers (for
example, sodium alkylsulphates and sodium alkylarylsulphonates, etc.) and of
radical initiators.
This definition specifically encompasses the "classic" polymerization in
aqueous emulsion, in which use is made, besides an aqueous polymerization
medium, of at least one water-soluble radical initiator (chosen, for example, from
water-soluble peroxides such as alkali metal or ammonium persulphates,
hydrogen peroxide, perborates, t-butyl hydroperoxide, etc.) and at least one
emulsifier; and also polymerization in aqueous microsuspension, also called
polymerization in homogenized aqueous dispersion, in which use is made of at
least one oil-soluble initiator (chosen, for example, from oil-soluble organic
peroxides and oil-soluble diazo compounds, etc.) and an emulsion of monomer
droplets is prepared by virtue of a powerful mechanical stirring and the presence
of emulsifiers.
Preferably, the hydrosol of the vinyl chloride polymer is obtained by
"classic" radical polymerization in aqueous emulsion.
The aqueous dispersions (also known as latices) of vinyl chloride polymer
thus produced, which are the hydrosols used in the process according to the
invention, contain elementary polymer particles having very small mean
diameters that may range from around 10 to around 5000 nm (nanometres),
preferably from around 50 to around 1500 nm.
The vinyl chloride polymer content of the hydrosol is advantageously
greater than 15% by weight, preferably greater than 20% by weight, very
particularly greater than 25% by weight. It is advantageously less than 50% by
weight, preferably less than 40% by weight, very particularly less than 35% by
weight.
The hydrosol that can be used according to the invention advantageously
also contains at least one plasticizer such as a dialkyl phthalate or an alkyl
adipate, and, optionally, other conventional additives, such as stabilizers, antifoaming
agents, anti-scaling agents, thickeners, pigments, dyes, etc. The
hydrosol does not advantageously contain an organic solvent.
For the implementation of the process according to the invention, the fibres
are immersed in the hydrosol in order to obtain fibres coated with said hydrosol.
For this purpose, the fibres, which are advantageously in one of the
aforementioned physical forms, may optionally be subjected firstly to one or
more of the following treatments:
- in the case of an assembly of elementary fibres, passing through a device to
spread the fibres apart in the transverse direction;
- passing through tension control means;
- antistatic treatment.
The fibres are then advantageously submerged in a bath of hydrosol having
dimensions suitable for ensuring their complete immersion, resulting in their
coating by the hydrosol. This immersion is advantageously carried out at a
temperature between 0°C and the glass transition temperature of the polymer,
preferably between 15°C and 40°C. This immersion is advantageously carried
out at a pressure between 0 .1 and 10 MPa, preferably in the vicinity of
atmospheric pressure (0.1 MPa). The respective amounts of fibres and of
hydrosol used are advantageously such that the final composite material
advantageously contains between 50% and 95%, preferably between 60% and
90% and particularly preferably between 70% and 90% by weight, of fibres and
advantageously between 50% and 5%, preferably between 40% and 10% and
particularly preferably between 30% and 10% by weight, of polymer.
The step of immersing the fibres in the hydrosol may be carried out
continuously or in batch mode. It is preferred to carry out this step continuously.
In this case, if the fibres are packaged on a reel or on a roll, they are
advantageously first unwound with a view to passing them into the bath of
hydrosol.
The immersion of the fibres in the hydrosol is then followed by the drying
of the hydrosol. Any known drying method that enables water to be removed
from a dispersion of a solid in an aqueous phase is suitable for drying the
hydrosol. It being understood that, in the process according to the invention, the
hydrosol to be dried is usually in the form of a film or a layer coating the fibres
and the thickness of which is often between 0 .1 and 1 mm, preferably between
0.2 and 0.6 mm, it may advantageously be dried - after optional scraping of the
possible surplus of hydrosol - for example by the following means, applied
separately or in combination: putting under vacuum; microwave heating;
application of infrared radiation; application of hot air via blowers or fans;
passing between heated and rotating rolls or between heated and fixed bars, etc.
The hydrosol is preferably dried by application of hot air, preferably heated
to a temperature below the decomposition temperatures of the hydrosol and of
the fibres. This temperature is preferably less than or equal to 160°C, more
particularly less than or equal to 150°C. Preferably, the temperature of the air for
drying the hydrosol is greater than or equal to 80°C, more particularly greater
than or equal to 110°C.
The drying of the hydrosol may be carried out continuously or in batch
mode. It is preferred to carry it out continuously. In the case where the drying of
the hydrosol is carried out continuously by application of air, use is
advantageously made of a drying tunnel or hot-air generators that are regularly
spaced along the path of the composite material being manufactured.
The drying may be carried out in a single step or in several steps which
may be carried out at different temperatures. It is preferably carried out in several
steps, particularly preferably in two steps and very particularly preferably in two
different steps with different temperatures.
After drying the hydrosol, it is gelled (i.e. its constituent particles change
from a heterogeneous phase to a homogeneous phase (free of grain structure)),
advantageously under the action of heat. The hydrosol may advantageously be
gelled by application of infrared radiation or laser radiation. The hydrosol is
preferably gelled by application of infrared radiation bringing the hydrosol to a
temperature above the glass transition temperature of the polymer that it contains
and below the decomposition temperature of the fibres. This temperature is
preferably less than or equal to 250°C, more particularly less than or equal to
230°C. Preferably, this temperature is greater than or equal to 100°C, more
particularly greater than or equal to 150°C.
Like the steps of immersing the fibres in the hydrosol and of drying the
hydrosol, the step of gelling the hydrosol may be carried out continuously or in
batch mode. It is preferred to carry out this step continuously.
The composite material, obtained at the end of the manufacturing process
described above, may then be subjected to treatments, the nature of which differs
depending on whether this material is intended either to be stored with a view to
a subsequent use, or to be used immediately (i.e. in-line with its manufacture).
In any case, the definitive shape of the composite material obtained is
advantageously imparted thereto by subjecting it to a shaping treatment capable
of giving it a uniform thickness, for example calendering or laminating in a press
or between cooled or uncooled rolls, optionally combined with a mechanical
treatment capable of giving it the desired uniform width, for example by passing
between blades positioned parallel to the longitudinal axis of the advancing
structure, or to a combination of these two methods.
The thickness of the composite material obtained may advantageously vary
between 0.1 and 3 mm, preferably between 0.15 and 2 mm, very particularly
between 0.2 and 1 mm. The width of the composite material obtained may be
very variable, depending on the physical form of the fibres from which it has
been made. In the frequent case where the composite material obtained is in the
form of a roving, this width is advantageously between 3 and 100 mm,
preferably between 5 and 50 mm, very particularly between 5 and 25 mm.
If the composite material is intended to be stored before it is used, it is
advantageously, after an optional supplementary cooling, wound around itself in
the form of a reel or roll if it is flexible or stored by stacking cut films or sheets if
it is rigid.
If the composite material is intended to be used immediately, it is
advantageously introduced into a suitable shaping device (see below).
In another aspect, the present invention relates to a composite material as
described above in connection with the process. In particular, the invention
proposes a composite material comprising fibres coated with at least one vinyl
chloride polymer by immersion of said fibres in a hydrosol of said polymer in
order to obtain fibres coated with said hydrosol followed by the drying and
gelling of said hydrosol coated on the fibres. The composite material according
to the invention is advantageously obtained by the process according to the
invention. The definitions, limitations and preferences mentioned and described
above for the process of the invention according to the invention apply therefore
to the composite material according to the invention.
Another aspect of the invention further relates to the use of the composite
material according to the invention or of the composite material obtained by the
process according to the invention for forming articles on the one hand, and for
manufacturing reinforced objects on the other hand. For this purpose, the
composite material may be used via any known method that is compatible with
its components, such as, for example, calendering, thermoforming, pultrusion,
coextrusion, etc.
The composite material according to the invention may be used as fibrous
reinforcement, for example for sheets for interior fittings in the motor vehicle
industry, in the shipbuilding industry, in furniture, in the building industry; as
external reinforcement for pipes and hose; as reinforcement for injectionmoulded
parts; etc.
Particularly advantageously, the composite material according to the
invention may be used for the manufacture of reinforced profiles made of a
thermoplastic, preferably made of rigid PVC, such as joinery elements,
especially elements of fixed frames and/or shutters and/or doors and/or gates
and/or window frames. In this application, the composite material according to
the invention advantageously improves the rigidity of the profiles and their
tensile strength in the longitudinal direction. Furthermore, the rigid PVC profiles
reinforced by composite structures of the invention are easily recyclable.
Another aspect of the invention finally relates to the articles or reinforced
objects obtained from the composite material described above or from the
composite material obtained by the process according to the invention described
above. This aspect of the invention relates more particularly to the profiles
reinforced by the composite material above or by the composite material
obtained by the process described above.
Should the disclosure of any patents, patent applications, and publications
which are incorporated herein by reference conflict with the description of the
present application to the extent that it may render a term unclear, the present
description shall take precedence.
The process for the manufacture of a composite material according to the
invention will now be illustrated by the examples below which refer to the
drawing that accompanies the present description. This drawing consists of the
appended Figure 1, schematically representing one practical embodiment of this
subject of the invention. Those examples are intended to illustrate the invention
without however limiting the scope thereof.
Example 1
A reel 1 delivered a "roving" of glass fibres supplied by the company
Owens Corning Vetrotex under the name RO 99 P 192 having a linear density of
4800 tex (4.8 g/m measured according to the standard ISO 1889), which were
treated with a silane-based coupling agent, and the diameter of the constituent
filaments of which was 24 m . This "roving", advancing at a speed of 2.5
m/min, was immersed, at 23°C and under atmospheric pressure, via the roll 2, in
a hydrosol bath 3, positioned in which were cylindrical bars 4, arranged in
staggered rows relative to one another and the respective heights and spacings of
which were adjustable in order to impose the desired tension on the "roving".
The hydrosol bath 3 had the following composition:
- 3 1.40% by weight of a dispersion of a vinyl chloride homopolymer having a
K-value equal to 72 (polymerized in classic aqueous emulsion) sold by the
company Solvin under the name 072 GA;
- 12.44% by weight of plasticizer (diisononyl phthalate);
- 0.65% by weight of heat stabilizer (di(w-octyl)tin thioglycolate);
- 0.9 1% by weight of an anionic emulsifier (mixture of fatty acid sodium salt
and of sodium dodecylbenzenesulphonate);
- 0.50% by weight of a nonionic emulsifier sold under the name Triton X 100
by Sigma Chemical;
- 0 .5% by weight of cellulose ether;
- 53. 6% by weight of water.
The "roving" of glass fibres impregnated with the hydrosol was drawn out
of the bath 3 by the series of cylindrical bars 5, which also ensured the correct
tension thereof, and conveyed between the fans 6 blowing air at 120°C at a flow
rate of 33 1/sec then between the fans 7 blowing air at 145°C at a flow rate of 17
1/sec.
The precursor of the composite material was then conveyed, in order to gel
the hydrosol for about twenty seconds, between the IR radiation diffusers 8, the
faces of which irradiating towards the structure are brought to a temperature of
220°C.
The composite material thus obtained, containing around 80% by weight of
glass fibres, was then passed between the laminating rolls 9 in order to shape it
into a tape having a thickness of 0.2 mm and a width of 10 mm, which was
collected on the reel 10.
In order to determine the mechanical properties of the composite material
thus obtained, pieces of the tape obtained were placed in a mould side by side
and on top of one another while orienting them in the same direction, in order to
obtain, after pressing, a sheet having a thickness of 1.7 mm.
The impact strength of these sheets, measured according to the standard
ISO 6603, was 7.6 J/mm. The tensile modulus, elongation at break and tensile
strength, measured in the longitudinal direction according to the standard ISO
527, were respectively 47.6 GPa, 0.71% and 301 MPa.
Example 2
A reel 1 delivered a "roving" of flax fibres supplied by the company
Depestele having a linear density of 0.5 g/m. This "roving" was then immersed
in a hydrosol bath as described in Example 1.
The hydrosol bath had the following composition:
- 3 1.04% by weight of a dispersion of a vinyl chloride homopolymer having a
K-value equal to 72 (polymerized in classic aqueous emulsion) sold by the
company Solvin under the name 072 GA;
- 12 .30% by weight of plasticizer (diisononyl phthalate);
- 0.65% by weight of heat stabilizer (di(w-octyl)tin thioglycolate);
- 0.90% by weight of an anionic emulsifier (mixture of fatty acid sodium salt
and of sodium dodecylbenzenesulphonate);
- 0.49% by weight of a nonionic emulsifier sold under the name Triton X 100
by Sigma Chemical;
- 1.14%o by weight of cellulose ether;
- 53.49% by weight of water.
The "roving" of flax fibres impregnated with the hydrosol was then treated
like the "roving" mentioned in Example 1.
The precursor of the composite material was then conveyed, in order to gel
the hydrosol for about twenty seconds, between the IR radiation diffusers 8, the
faces of which irradiating towards the structure were brought to a temperature of
200°C.
The composite material thus obtained, containing around 50% by weight of
flax fibres, was then passed between the laminating rolls 9 in order to shape it
into a tape having a thickness of 0.2 mm and a width of 5 mm, which was
collected on the reel 10.
In order to determine the mechanical properties of the composite material
thus obtained, pieces of the tape obtained were placed in a mould side by side
and on top of one another while orienting them in the same direction, in order to
obtain, after pressing, a sheet having a thickness of 0.5 mm.
The tensile modulus, elongation at break and tensile strength, measured in
the longitudinal direction according to the standard ISO 527, were respectively
14.6 GPa, 1.67% and 190 MPa.
The mechanical properties of a fabric made from the impregnated tapes
were also determined. In order to do this, the tapes were woven and the fabric
obtained was placed in a mould, in several thicknesses while orienting the fibres
of the fabric in the same direction, in order to obtain, after pressing, a sheet
having a thickness of 0.97 mm.
The tensile modulus, elongation at break and tensile strength, measured
according to the standard ISO 527, were respectively 8.3 GPa, 1.69% and 100
MPa.
Example 3
A reel 1 delivered a "roving" of basalt fibres supplied by the company
Flocart under the name KVT1200Texl3EKVl 1, having a linear density of 1200
tex (measured according to the standard ISO 1889). This "roving" was then
immersed in a hydrosol bath as described in Example 1.
The hydrosol bath had the same composition as in Example 2 .
The "roving" of basalt fibres impregnated with the hydrosol was then
treated like the "roving" mentioned in Example 1.
The precursor of the composite material was then conveyed, in order to gel
the hydrosol for about twenty seconds, between the IR radiation diffusers 8, the
faces of which irradiating towards the structure are brought to a temperature of
190°C.
The composite material thus obtained, containing around 80% by weight of
basalt fibres, was then passed between the laminating rolls 9 in order to shape it
into a tape having a thickness of 0.2 mm and a width of 4 mm, which was
collected on the reel 10.
In order to determine the mechanical properties of the composite material
thus obtained, pieces of the tape obtained were placed in a mould side by side
and on top of one another while orienting them in the same direction, in order to
obtain, after pressing, a sheet having a thickness of 0.78 mm.
The tensile modulus, elongation at break and tensile strength, measured in
the longitudinal direction according to the standard ISO 527, were respectively
43.9 GPa, 0.05% and 397 MPa.
The mechanical properties of a fabric made from the impregnated tapes
were also determined. In order to do this, the tapes were woven and the fabric
obtained was placed in a mould, in several thicknesses while orienting the fibres
of the fabric in the same direction, in order to obtain, after pressing, a sheet
having a thickness of 0.52 mm.
The tensile modulus, elongation at break and tensile strength, measured
according to the standard ISO 527, were respectively 12 GPa, 0.47 % and 263
MPa.
A use of the composite material, obtained according to Example 1, for
manufacturing reinforced profiles is illustrated by referring to another drawing
that accompanies the present description. This drawing consists of the appended
Figure 2, schematically representing, in perspective, a partially exploded cross
section of a device 13 for shaping the profiles. The cross section is made along a
plane that passes vertically through the device 13 in its middle (of which only the
rear half is thus displayed), perpendicular to the plane of the composite material
in the form of a tape 11 obtained as described above and to the direction of travel
of this tape, indicated by the arrow F 1.
The shaping device 13 was supplied, on the one hand, with the tape 11, via
the adapting piece 17 equipped with a through slit 19 and, on the other hand,
with a die 15, located at the end of the screw head 14 of a conventional extruder
(not represented) which provided, under pressure, molten PVC, introduced in the
direction of the arrow F2.
The exploded part of the cross section of the shaping device 13 makes it
possible to display the molten PVC feed means 14 and 15 and the route of this
molten PVC into the shaping device 13, via the channels 16 and 16 bis, in order
to emerge in front of the through slit 19 at the front end of the adapting piece 17,
on top of and underneath the advancing tape 11. The through slit 19 is bordered
by 2 walls 18 and 18 bis so that the molten PVC homogeneously coats the two
faces of the tape 11 in order to result in the profile 1 emerging from the device
13 in the direction of the arrow F3.
A profile reinforced by the composite material according to the invention is
illustrated by referring to another drawing that accompanies the present
description. This drawing consists of the appended Figure 3 which represents a
section of an opening window frame made of PVC. This opening frame has been
reinforced by a composite material 20 in the form of a 2 mm-thick tape
manufactured as indicated in Figure 1 and its description above. This structure
has made it possible to increase the length of the opening frame by more than
60% compared to an unreinforced profile and by 10% compared to a profile
reinforced by a 1mm steel reinforcement.

C L A I M S
1 - Process for manufacturing a composite material comprising fibres and
at least one vinyl chloride polymer comprising the immersion of the fibres in a
hydrosol of said polymer in order to obtain fibres coated with said hydrosol
followed by the drying and gelling of said hydrosol coated on the fibres.
2 - Process according to Claim 1, characterized in that the fibres are an
assembly of elementary fibres chosen from woven fabrics, nonwoven fabrics and
rovings.
3 - Process according to Claim 1 or 2, characterized in that the fibres are
fibres resulting from products of plant origin chosen from hemp and flax.
4 - Process according to any one of Claims 1 to 3, characterized in that the
fibres are mineral fibres chosen from glass fibres and basalt fibres.
5 - Process according to any one of Claims 1 to 3, characterized in that the
fibres are rovings of flax fibres, rovings of glass fibres or rovings of basalt fibres.
6 - Process according to any one of Claims 1 to 5, characterized in that the
vinyl chloride polymer is a homopolymer.
7 - Process according to any one of Claims 1 to 6, characterized in that the
hydrosol of the vinyl chloride polymer is obtained by radical polymerization in
aqueous emulsion.
8 - Process according to any one of Claims 1 to 7, characterized in that the
fibres are submerged in a bath of hydrosol having dimensions suitable for
ensuring their complete immersion, resulting in their coating by the hydrosol.
9 - Process according to any one of Claims 1 to 8, characterized in that the
hydrosol is dried by application of hot air, preferably heated to a temperature
below the decomposition temperatures of the hydrosol and of the fibres.
10 - Process according to any one of Claims 1 to 9, characterized in that
the hydrosol is gelled by application of infrared radiation bringing the hydrosol
to a temperature above the glass transition temperature of the polymer that it
contains and below the decomposition temperature of the fibres.
11 - Composite material comprising fibres coated with at least one vinyl
chloride polymer by immersion of said fibres in a hydrosol of said polymer in
order to obtain fibres coated with said hydrosol followed by the drying and
gelling of said hydrosol coated on the fibres.
12 - Use of the composite material according to Claim 11 or of the
composite material obtained by a process according to any one of Claims 1 to 10
for forming articles.
13 - Use of the composite material according to Claim 11 or of the
composite material obtained by a process according to any one of Claims 1 to 10
for manufacturing reinforced objects.
14 - Articles or reinforced objects obtained from the composite material
according to Claim 11 or from the composite material obtained by a process
according to any one of Claims 1 to 10.
15 - Profiles reinforced by the composite material according to Claim 11 or
the composite material obtained by a process according to any one of Claims 1
to 10.