AU2002364347B2

AU2002364347B2 - Composite yarn, method for obtaining same and resulting textile structure

Info

Publication number: AU2002364347B2
Application number: AU2002364347A
Authority: AU
Inventors: Philippe Berge; Isabelle Conesa; Laurence Pollet
Original assignee: Chavanoz Industrie SARL
Current assignee: Chavanoz Industrie SARL
Priority date: 2001-12-28
Filing date: 2002-12-27
Publication date: 2008-01-31
Anticipated expiration: 2022-12-27
Also published as: JP2005513299A; DE60221707T2; CN1608153A; ES2291533T3; FR2834302A1; HK1072280A1; JP4272530B2; CA2470453A1; BR0215350A; DK1458910T3; ATE369448T1; EP1458910B1; WO2003056082A2; FR2834302B1; WO2003056082A3; CN1608153B; BR0215350B1; KR20040071760A; KR100903989B1; AU2002364347A1

Abstract

The invention concerns a composite yarn consisting of a continuous yarn, obtained by spinning fibers made of organic or inorganic material or natural fibers, and a polymer material. The invention is characterized in that the consecutive fibers said yarn are uniformly distributed in said polymer material such that each of said fibers is coated by said polymer material. The invention also concerns a method for making such a composite yarn and a textile structure obtainable from at least a composite yarn of the invention.

Description

IN THE MATTER OF an Australian Application corresponding to PCT Application PCT/FR02/04577 RWS Group Ltd, of Europa House, Marsham Way, Gerrards Cross, Buckinghamshire, England, hereby solemnly and sincerely declares that, to the best of its knowledge and belief, the following document, prepared by one of its translators competent in the art and conversant with the English and French languages, is a true and correct translation of the PCT Application filed under No. PCT/FR02/04577.

Date: 11 June 2004 C. E. SITCH Deputy Managing Director UK Translation Division For and on behalf of RWS Group Ltd COMPOSITE YARN, METHOD FOR OBTAINING SAME AND RESULTING CI TEXTILE STRUCTURE

Z

00 oO The present invention relates to a composite yarn for technical or industrial use, that can be assembled into all types of textile structure, especially textile webs suitable for meeting any particular application or specification, for example for the manufacture of blinds or curtains.

Cn, More particularly, the invention relates to composite yarns that can be obtained by coating.

C In this specification where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date publicly available, known to the public, part of the common general knowledge or known to be relevant to an attempt to solve any problem with which this specification is concerned.

Already generally known, and as manufactured and sold by the Applicant, are technical composite yarns comprising: a core comprising a continuous yarn, especially made of an inorganic material such as glass, or an organic material such as polyester, polyamide or polyvinyl alcohol, and a sheath or jacket comprising a matrix consisting of at least one chlorinated polymer material, for example a polyvinyl chloride (PVC), a fire-retardant mineral filler, incorporated into and distributed within said matrix, and a plasticizer.

Preferably, but not exclusively, such a yarn is obtained by coating, in one or more layers, the core with a plastisol comprising the chlorinated polymer material, for example polyvinyl chloride, and the plasticizer, and then by gelling the plastisol around the core.

The technical fabrics obtained with such yarns, and when they are used in various environments, especially for the equipping both inside and outside of buildings or constructions, for example as blinds, have to meet requirements regarding fire behaviour that are defined by national or international regulations and/or 9026901 I.doc 2 homologation or authorization procedures.

Thus, the regulations applicable to such fabrics in the German Federal Republic define various classes that are characterized in particular by the specimen length destroyed by fire, and by the temperature of the combustion smoke, said classes being identified by the letters B1 to B3, the letter B1 characterizing the best fire behavior that can be obtained by a material containing organic matter.

The regulations applicable in France also define various classes according to the NF 1601 and NF P 92503 standards, on the one hand, characterized especially by the emission of smoke and identified by the letters FO to F5, F3 being the best behavior that can be obtained by a material containing a halogenated polymer, and, on the other hand, characterized in particular by the residual ignition temperature of the fabric and identified by the letters MO to M4, the letter M1 identifying the best fire behavior that can in general be obtained by a material containing organic matter.

Various attempts have been made to improve the intrinsic fire behavior of these composite yarns, for example by using particular plasticizers such as organic phosphates. Unfortunately, the use of such plasticizers degrades the functional properties (flexibility, slipability, etc.) of these yarns, which impairs their subsequent weaving, and makes the latter more difficult. Moreover, the incorporation of such plasticizers increases the smoke index.

With regard to the performance of the actual fireretarding filler, various documents have proposed diverse types of compounds or compositions that can improve the fire behavior of plastic matrices in which the fire-retarding filler has been incorporated, but without the application or the forming of the fire- 3 retarded plastic, for example in the form of a yarn, being specified.

Thus, document JP-A-58185637 has proposed, for a matrix based on polyvinyl chloride, a fire-retarding filler comprising a chlorinated polyethylene, a compound chosen in particular from antimony and aluminum oxides and/or hydroxides, and preferably another compound chosen from zinc salts, including zinc borate, and tinbased products, for example zinc stannate.

Document FR-A-2 448 554 has proposed, again for a matrix based on polyvinyl chloride and also incorporating a stabilizer, a plasticizer consisting of a phosphoric ester, and an alumina hydroxide filler, a fire-retarding filler comprising an antimony oxide, optionally combined with a zinc borate.

None of the fire-retarding fillers proposed above is suitable for improving to the desired extent the fire behavior of a composite yarn as considered above, and without degrading its other properties, for example mechanical properties.

Nor is it possible to significantly increase the weight proportion of fire-retarding filler, except at the expense, as above, of degrading the functional properties of the composite yarn.

The subject of the present invention is a coated composite yarn exhibiting, overall and intrinsically, improved fire behavior, thus favoring the dissipation of heat and making it possible to greatly reduce the random phenomenon of flame propagation measured by fire tests according to the NF P 92 503 standard on any fabric obtained from the composite yarn according to the invention.

The temperature withstand properties are improved owing 4 to the uniform distribution of the fibers within the polymer coating material that allows the heat to be dissipated since, when the fibers are grouped together, they constitute a preferential conduction path that promotes heat propagation.

The subject of the invention is a composite yarn consisting of a continuous yarn, obtained by spinning fibers made of an organic or inorganic material or natural fibers, such as flax or cotton fibers, and of a polymer material, characterized in that the constituent fibers of said continuous yarn are uniformly distributed within said polymer material in such a way that each of said fibers is coated by said polymer material.

This composite yarn can be used by itself or as a core for the manufacture of composite yarns obtained by a second coating with a polymer material.

The subject of the present invention is also a coated composite yarn that can be obtained by a process for coating with a polymer material, characterized in that it comprises a core consisting of a composite yarn as defined above and in that the polymer material formed around the core and the constituent polymer material of the core are of the same nature.

Depending on the required fire behavior characteristics, this composite yarn can be used as a core for the manufacture of fire-retarded composite yarns obtained by coating with polymers containing fire-retarding fillers.

Thus, yarns exhibiting overall and intrinsically improved fire behavior using less fire-retarding filler are obtained.

The subject of the present invention is also a coated 5 fire-retarded composite yarn that can be obtained by a process for coating with a polymer material containing a fire-retarding filler, characterized in that it comprises a core consisting of a composite yarn as defined above and in that the polymer material formed around the core and the constituent polymer material of the core are of the same nature.

According to the invention, said coating can be carried out using a liquid monomer or polymer preparation; for example, a liquid polymer preparation is obtained by melting a polymer or by dispersing a polymer, for example in the form of a plastisol; and, for example, a liquid monomer preparation consists of a liquid monomer that will polymerize through the effect of heat or by irradiation, for example UV irradiation.

The invention also relates to a process for manufacturing a composite yarn, characterized in that a continuous yarn, obtained by spinning fibers made of an organic or inorganic material or natural fibers, is subjected to a process for mechanically opening the yarn that allows said fibers to be separated, simultaneously with or prior to its coating by a polymer material.

The invention furthermore relates to a process for manufacturing a composite yarn, characterized in that a continuous yarn, obtained by spinning fibers made of an organic or inorganic material or natural fibers, is subjected to a process for mechanically opening the yarn that allows said fibers to be separated, simultaneously with or prior to a primary coating with a liquid monomer preparation or a polymer preparation in the liquid state, and in that the composite yarn obtained is subjected to a second coating with a liquid monomer or polymer preparation.

Preferably, the monomer or polymer of the second 6 coating is of the same nature as the monomer or polymer of the first coating.

The invention furthermore relates to a process for manufacturing a fire-retarded composite yarn, characterized in that a continuous yarn, obtained by spinning fibers made of an organic or inorganic material or natural fibers, is subjected to a process for mechanically opening the yarn that allows said fibers to be separated, simultaneously with or prior to a primary coating with a liquid monomer preparation or polymer preparation in the liquid state that does not contain a fire-retarding filler, and in that the composite yarn obtained is subjected to a second coating with a liquid monomer preparation or polymer preparation in the liquid state containing a fireretarding filler.

The expression "mechanically opening" is understood to mean any process for opening the fibers, simultaneously with or prior to the coating operation, such as splaying the fibers, by applying an air jet or a water jet, an ultrasonic treatment, the application of mechanical pressure, for example to flatten the yarn, or any process for separating the fibers in order to allow the polymer material to penetrate the constituent fibers of said yarn.

The yarn according to the invention exhibits none of the desheathing and shading phenomena observed in the yarns of the prior art.

These results are obtained without impairing the functional properties of the actual yarn, that are required for weaving it, and these properties are even improved. Thus, the fabrics obtained by weaving these composite yarns are better protected from foul weather, by the elimination or reduction in capillary wicking, and are easier to cut by elimination of defibrillation 7 phenomena that occur on cutting.

The expression "liquid monomer or polymer preparation" is understood to mean any liquid formulation based on monomers or polymers.

The term "formulation" is understood to mean any compound comprising at least one product, for example a dispersion, solution or mixture of monomers and/or oligomers.

The term "polymer dispersion" is understood to mean any polymer preparation in the divided state containing additives in an organic liquid or otherwise.

The term "plastisol" is understood to mean a dispersion of polymers, fillers and other additives, in a finely divided state, in a plasticizer.

As polymer material, it is possible to use chlorinated polymers, silicones, polyurethanes, acrylics, ethylene/vinyl acetate EVA copolymers and ethylenepropylene-diene monomer EPDM terpolymers.

As an example of a chlorinated polymer material, it is possible to use, according to the invention, any PVC resin that can be plasticized and especially one that can be employed in the form of a plastisol.

The term "chlorinated polymer material" is understood to mean a pure chlorinated polymer or a copolymer of vinyl chloride copolymerized with other monomers, or else a chlorinated polymer that is alloyed with other polymers.

Among monomers that can be copolymerized with vinyl chloride, mention may in particular be made of: olefins, such as for example ethylene; vinyl esters of saturated carboxylic acids, such as vinyl acetate, 8 vinyl butyrate or maleates; halogenated vinyl derivatives, such as for example vinylidene chloride; and acrylic or methacrylic acid esters, such as butyl acrylate.

As chlorinated polymer, mention may in particular be made of polyvinyl chloride, and also superchlorinated PVCs, polyvinylidene chlorides and chlorinated polyolefins.

Preferably, but not exclusively, the chlorinated polymer material according to the present invention has a halogen weight content of between 40 and According to the invention, it is possible to use, as silicone polymer material, organopolysiloxanes and more particularly polysiloxane resins and elastomers with or without a diluent.

According to the invention, it is possible to use, as polyurethane polymer material, any material formed from a hydrocarbon chain containing the urethane or -NHCOOunit.

As regards the continuous yarn, this itself consists of one or more continuous filaments or fibers. Its chemical nature may be organic, for example made of polyester, polyamide, polyvinyl, or acrylic, of natural origin, such as flax or cotton, or inorganic, for example made of glass or silica, it being understood that its melting point must be above that at which the polymer material is processed.

The fire-retarding filler is chosen from the group formed by zinc borate, aluminum hydroxide, antimony trioxide and zinc hydroxystannate, molybdenum compounds, halogenated derivatives, compounds containing active halogens, phosphorus compounds, and intumescent systems.

9 Other fillers may be incorporated and distributed within the liquid monomer or polymer preparation, in addition to the fire-retarding filler, for example a pigmenting filler, silica, talc, glass beads and/or a stabilizer. In such a case, the total composition by weight of the composite yarn, in terms of inorganic materials, is obviously modified or affected.

In the case of the use of a plastisol, thanks to the invention it remains possible to use conventional plasticizers, for example comprising at least one phthalate, and consequently not to compromise the functional properties of the yarn, with regard to its subsequent weaving.

The invention also makes it possible to limit the weight of fire-retarding filler, in proportions not exceeding 50% of the plastic matrix. Above 50%, the properties, especially mechanical properties, of the composite yarn are impaired.

All the technical characteristics of the yarn are improved. More particularly, the uniform distribution of the polymer material formed around the core, the resistance to capillary effects, the homogeneity of the shades, and the bonding of the sheath to the core should be noted.

In the case of the use of a PVC plastisol, the addition of a bonding agent of the isocyanate type is unnecessary.

Figure 1 shows in cross section a fire-retarded composite yarn of the prior art.

Figure 2 shows in cross section a fire-retarded composite yarn according to the invention.

10 Uniform distribution of the fibers 1 within the monomer or polymer preparation 2 applied in the liquid state and cooled or polymerized after application may be observed. The secondary coating 3 is also uniformly distributed in the composite yarn according to the invention.

The following comparative table illustrates all these characteristics, by comparison with a conventionally coated yarn, in the particular case of the use of a chlorinated polymer material, namely PVC.

1 Standard coating Coating according to the invention Yarn Twist 40 turns Possibility of using twists 40 turns 1 st coating 1 500 mPa.s 100 fire-retarded PVC 350 mPa.s plastisol: plastisol: PVC resin 100 phr PVC resin 100 phr -filler content 0 filler (fire-retardant) content 15 to plasticizer content 60 to 70 phr plasticizer content 60 to 70 phr phr stabilizers 2-10 phr plasticizer content 30 to 50 phr stabilizers 2-10 phr stabilizers 2-10 phr Degree of application 65 to yar diameter: 0.3 mm 2 n d coating Fire-retarded PVC plastisol identical 1 500 mPa.s fire-retarded PVC to the first coating plastisol; degree of application 30 to PVC resin 100 phr filler (fire-retardant) content 15-25 phr plasticizer content 30-50 phr stabilizers 2-10 phr Properties of LOI 30.7%: LOI the coated slight shading no shading yarn slight desheathing no desheathing fire-retardant content 8 to 15% fire-retardant content reduced by about fire-retardant content no chimney effect 1s coating: 45% PVC st coating: 41% PVC 2 nd coating: 24% PVC 2 nd coating: 30% PVC Properties of M1 B MI maintained and more uniform the fabric the fabric Slightly shaded

BI

Slight desheathing (sheath Constancy of mechanical properties fracturing under mechanical stress) under stress (glass yarn not destroyed) No shading No desheathing No defilbrillation No capillary effect 12 The degree of application is the amount of impregnation of the yarn it is defined by the following formula: weight of the coated yarn- weight of the yarn 1 x 100; weight of the coated yarn LOI represents the Limited Oxygen Index it is determined according to the NF G 07128 standard.

To prepare formulations according to the invention, based on a chlorinated polymer such as PVC, the following ingredients were used by way of example: Resins: a. PVC resin VINNOLIT P4472, VINNOLIT P70, VINNOLIT P70 PS (Vinnolit), SELIN 372 No. (Selvan); b. filler resin LACOVYL B 1050 (Atofina), VINNOLIT (Vinnolit), VINNOLIT C66 (Vinnolit), C66W.

Plasticizers: DINP (JAYFLEX DINP, PALATINOL N (BASF), VESTINOL 9 (Oxeno)), TXIB (Eastman TXIB), DIDP (JAYFLEX DIDP (Exxon), PALATINOL Z (BASF)), BBP (SANTICIZER 206) (Ferro).

Stabilizers: a. Heat stabilizers based on Pb (BAEROSTAB V 220) (Baerlocher) based on barium and zinc organic salts (LASTAB DC 261 GL (Lagor), MARK BZ 561 (Witco)) based on thiotin (BAEROSTAB M62 A (Baerlocher)) b. UV stabilizer Benzotriazole or benzophenone (TINUVIN 320, TINUVIN 571, TINUVIN P (Witco)).

Fillers: Opacifying fillers: zinc sulfide ZnS (SACHTOLIT L (Sachtleben)), titanium dioxide (Kronos).

Fire retardants: Zinc borate (FIREBREAK ZB (US Borax)) Aluminum hydroxide (Alumina SH 5) (Omya) Antimony trioxide (antimony oxide/TIMONOX) (Sica, 13 Campine, plc) Zinc hydroxystannate (STORMFLAM ZHS (Joseph Storey).

Additives: Viscosity modifiers/rheology agents: VISCOBYK- 4013, CAB-O-SIL, EXXSOL D80 (Byk-Chemie, Cabot, Exxon).

Wetting agents: DISPERPLAST-1142 (Byk-Chemie).

Since glass favors heat dissipation, the phenomenon of flame propagation encountered in fire tests according to the NF 92503 standard on fabrics is, with a fabric obtained by weaving a fire-retarded yarn according to the invention, greatly reduced as the polymer material is better distributed within the core of the fibers and the stored heat is therefore better dissipated by the fibers.

This dissipation optimization makes it possible overall to reduce the content of fire-retardant fillers in the coated fire-retarded composite yarn.

The following examples illustrate the invention in the particular case of the use of a silicone-based polymer material.

A halogen-free coated fire-retarded composite yarn according to the invention was obtained by coating a mineral yarn/continuous glass fiber/continuous glass filament according to the process of the invention, that is to say by mechanically opening the yarn, by splaying it, simultaneously with or prior to the coating operation with a liquid polymer preparation based on a silicone polymer.

The coating formulation was defined by a viscosity between 500 and 10 000 mPa.s and preferably between 1 000 and 5 000 mPa.s, measured at 25 0 C using a Brookfield RVT viscometer at 20 rpm with a No. 4 spindle.

14 The coating was carried out with a formulation comprising the following products: Silicone 100 phr Solvent/water 0 to 50 phr Fillers (pigment, fire retardant, etc.)0 to 20 phr Crosslinking agent 2 to 6 phr Additives 0 to 5 phr Additives 0 to 5 phr.

The silicones used were, for example: ELASTOSIL RD6635, RD 3151 or 45539 WP (Wacker), RHODOSIL RTV 1519 (Rhodia), DOW FC227TS (Dow Corning), 9050/30P from Dow Corning, 6600 F from Wacker, SILASTIC LPX from Dow Corning, SILICOLEASE UV POLY 200 and UV CATA 211 from Rhodia.

The diluents were chosen from toluene, xylene, white spirit and water.

The fillers consisted for example of FIREBREAK ZB zinc borate, aluminum hydroxide (Omya), SH5n alumina, promoter such as ELASTOSIL 45568 VP or HF86 (Wacker), retarder HTV-SB (Wacker), water-repellent agent (Wacker) or glass beads (Sovitec), RAL pigmentary paste from Wacker.

The following formulations were made and composite yarns according to the invention obtained by coating.

Example 1: First coating: 30% degree of application 9050/30P from Dow Corning (3 000 cP viscosity) 100 phr Second coating, 30% degree of application 9050/30P 100 phr SILASTIC (Dow Corning) 2 phr 15 Example 2: First coating, 15% degree of application 9050/30P from Dow Corning Second coating, 15% degree of application RD3151 (Wacker) 100 phr HTV-SB Batch 2 (Wacker) 0.5 phr FIREBREAK Zn borate 5 phr RAL pigmentary paste (Wacker) 2 phr ELASTOSIL W crosslinking agent (Wacker) 3 phr Example 3: Single coating 18% degree of application 6600 F (Wacker) 100 phr HTV-SB Batch 2 (Wacker) 1 phr ATH (Alcan) 20 phr ELASTOSIL W crosslinking agent (Wacker) 5 phr Toluene 20 phr Example 4: The silicones used were UV-crosslinkable.

First coating: SILICOLEASE UV POLY 200 (Rhodia) 100 parts SILICOLEASE UV CATA 211 (Rhodia) 2 to 5 parts Second coating: SILICOLEASE UV POLY 200 (Rhodia) 100 parts SILICOLEASE UV CATA 211 (Rhodia) 2 to 5 parts Fire-retarding fillers Pigment.

The fabrics obtained with a composite yarn according to the invention require no subsequent treatment in order to improve their fire behavior.

A composite yarn according to the invention exhibits no defibrillation on cutting, it is more hydrophobic and it is "softer" to the touch; the textiles obtained by weaving are stain-resistant.

A composite yarn according to the present invention can -16c1 be incorporated into any textile structure, or assembled as any required structure, whether two- Sdimensional (webs, fabrics, etc.) or three-dimensional (for example braids).

00 The composite yarn may firstly be cut and divided into elementary yarns, which can be intermingled and fastened to one another, in the form of nonwoven textile structures, for example mats. The intermingled elementary yarns may be fastened by impregnation with a suitable adhesive substance, or by the thermal melting of the polymer material of the sheath.

The composite yam may then be assembled on itself in any suitable knitted textile structure, but it may also be assembled with other yarns, whether or not according to the present invention, in order to constitute various two-dimensional or three-dimensional structures; in the latter case, these may be meshes in which the yams according to the present invention are interlaced with and fastened to other yarns, whether or not according to the present invention, and fabrics in which the composite yarns according to the invention are woven with other warp and/or weft yarns, again whether or not according to the invention.

A very particular application of the present invention relates to the production of technical fabrics intended for the production or manufacture of both interior and exterior blinds or curtains.

After fire tests, all these fabrics have shown that they meet both the German regulations with class B 1 and the French regulations with class M I and F3.

The word 'comprising' and forms of the word 'comprising' as used in this description and in the claims does not limit the invention claimed to exclude any variants or additions.

Claims

2. A composite yarn that can be obtained by a process for coating with a liquid monomer (-i or polymer preparation comprising a polymer material, characterized in that it comprises a core consisting of a composite yarn as claimed in claim 1, and in that the material formed around the core and the constituent polymer material of the core are of the same nature.
3. A fire-retarded composite yarn that can be obtained by a process for coating with a liquid monomer or polymer preparation comprising a polymer material and a fire-retarding filler, characterised in that it comprises a core consisting of a composite yam as claimed in claim I and in that the material formed around the core and the constituent polymer material of the core are of the same nature.
4. The composite yarn as claimed in any one of claims I to 3, characterized in that the inorganic or organic material constituting the fibers of the yarn is chosen from a group consisting of polyester, glass or silica.
5. The composite yarn as claimed in any one of claims 1 to 3, characterized in that the polymer material is chosen from chlorinated polymers.
6. The composite yarn as claimed in claim 5, characterized in that the chlorinated polymer material is chosen from the group consisting of polyvinyl chloride, superchlorinated PVCs, polyvinylidene chlorides and chlorinated polyolefins.
7. The composite yarn as claimed in any one of claims I to 3, characterized in that the polymer material is chosen from organopolysiloxanes.
8. The composite yarn as claimed in any one of claims 1 to 3, characterized in that the polymer material is chosen from polyurethanes.
9. The composite yarn as claimed in claim 3, characterized in that the fire-retarding filler is chosen from the group consisting of zinc borate, aluminum hydroxide, antimony trioxide and zinc hydroxystannate. 18 6. The composite yarn as claimed in claim characterized in that the chlorinated polymer material is chosen from the group consisting of polyvinyl chloride, superchlorinated PVCs, polyvinylidene chlorides and chlorinated polyolefins. 7. The composite yarn as claimed in any one of claims 1 to 3, characterized in that the polymer material is chosen from organopolysiloxanes. 8. The composite yarn as claimed in any one of claims 1 to 3, characterized in that the polymer material is chosen from polyurethanes. 9. The composite yarn as claimed in claim 3, characterized in that the fire-retarding filler is chosen from the group consisting of zinc borate, aluminum hydroxide, antimony trioxide and zinc hydroxystannate. A process for manufacturing a composite yarn, characterized in that a continuous yarn, obtained by spinning fibers made of an organic or inorganic material, is subjected to a process for mechanically opening the yarn that allows said fibers to be separated, simultaneously with or prior to its coating by a polymer material.
11. A process for manufacturing a composite yarn, characterized in that a continuous yarn, obtained by spinning fibers made of an organic or inorganic material, is subjected to a process for mechanically opening the yarn that allows said fibers to be separated, prior to a primary coating with a liquid monomer or polymer preparation, and in that the composite yarn obtained is subjected to a second coating with a liquid monomer or polymer preparation. 19
12. A process for manufacturing a fire-retarded composite yarn, characterized in that a continuous yarn, obtained by spinning fibers made of an organic or inorganic material, is subjected to a process for mechanically opening the yarn that allows said fibers to be separated, prior to a primary coating with a liquid monomer or polymer preparation that does not contain a fire-retarding filler, and in that the composite yarn obtained is subjected to a second coating with a liquid monomer or polymer preparation containing a fire-retarding filler.
13. The process as claimed in either of claims 11 and 12, characterized in that the monomer or polymer of the second coating is of the same nature as the monomer or polymer of the first coating.
14. A textile structure, for example a fabric, characterized in that it can be obtained from at least one composite yarn as claimed in any one of claims 1 to