EP1649087A2

EP1649087A2 - Abrasion-resistant wires, fibres and filaments

Info

Publication number: EP1649087A2
Application number: EP04767768A
Authority: EP
Inventors: Florence Clement; Franck Bouquerel; Gilles Robert; Jean-François Thierry
Original assignee: Rhodia Performance Fibres SAS
Current assignee: Rhodia Performance Fibres SAS
Priority date: 2003-07-25
Filing date: 2004-07-23
Publication date: 2006-04-26
Also published as: WO2005019510A2; TW200523409A; AU2004266274B2; FR2857984A1; FR2857984B1; CA2533619C; AU2004266274A1; TWI333005B; CA2533619A1; WO2005019510A3; CN1853007B; BRPI0412604A; JP4489769B2; CN1853007A; US20060275604A1; JP2006528734A

Abstract

The invention relates to wires, fibres and filaments having improved resistance to abrasion, which are suitable, for example, for the production of felts for papermaking machines. In particular, the invention relates to polyamide- or polyester-based wires, fibres and filaments.

Description

SON. FIBER. ABRASION RESISTANT FILAMENTS

The present invention relates to yarns, fibers or filaments, having improved abrasion resistance, and in particular usable for the production of felts for paper machines. It relates more particularly to yarns, fibers or filaments based on polyamide or polyester. The properties which must be present in spun articles are different according to their use. Among these, there may be mentioned for example the mechanical resistance, the transparency, the gloss, the whiteness, the dyeability, the shrinkage, the water retention capacity, the fire resistance, the stability and the heat longevity ... A property which may be required, in particular for applications in industrial fields or in so-called technical wire fields, is abrasion resistance. This is the case for example of felts, which are composite structures comprising a stack of layers of woven fabrics (obtained from continuous monofilaments) and layers of nonwovens (obtained from cut fibers), the layers being assembled in general by needling. The increase in abrasion resistance generally makes it possible to increase the life of articles made from yarns, fibers or filaments. In the case of felts for paper machines, which are made from synthetic fibers, this property has become critical for many reasons: replacement of chemical bleaching agents by solid particles, for example calcium carbonate, increase in the speed of production or operating temperatures of paper machines that stress felts more critically. This is also the case, for example, for carpets and rugs, cords and belts, nets, fabrics used in the field of screen printing or filtration. In this case, the mechanical stresses of friction or abrasion on these articles are such that the abrasion resistance property directly characterizes their lifespan. One known solution for improving the abrasion resistance of spun articles is to increase the degree of polymerization of the synthetic material from which they are made. Thus are developed fibers made from thermoplastic resins of increasing molecular weight. This increase in molecular weight results in an increase in the melt viscosity of the polymer. The spinning of fibers of very high melt viscosity in fact requires the use of very high spinning pressures and / or very high spinning temperatures which can cause degradation of the polymer. A possible alternative, described in patents US 5,234,644 and US 5,783,501, consists in producing yarns or fibers of conventional molecular weights and then increasing, a posteriori (on the fiber in the case of US5234644 or on the felt in the case of US5783501), the viscosity of the polymers. This solution has limitations, however. Thus this adds an additional step in the process and requires the use of chemical solutions containing catalysts. Another known solution consists in spinning polymers of high molecular mass but which one seeks to reduce the melted viscosity. This can be obtained through the use of polymers comprising star macromolecular chains. The polymers comprising such star macromolecular chains are for example described in the documents FR 2,743,077, FR 2,779,730, US 5,959,069, EP 0.632,703, EP 0.682,057 and EP 0.832,149. These compounds are known to have improved fluidity compared to linear polyamides of the same molecular weight. However, the yarns, fibers or filaments obtained from these polymers do not have good abrasion resistance properties. Another solution for improving the abrasion resistance of articles made from fibers consists in using articles having a three-dimensional crimp, as described in patent CA 2076726. It is also known to improve the abrasion resistance of spun articles to introduce nanometric-sized particles into the threads, such as silica or montmorillonite. These articles are in particular described in document WO01 / 02629. The object of the present invention is to propose another solution for obtaining spun articles with high abrasion resistance. To this end, the invention provides yarns, fibers and filaments resistant to abrasion obtained from a composition comprising a polymer matrix, the polymer matrix consisting of a polycondensate consisting of: 30 to 100% molar (limits included) of macromolecular chains corresponding to the following formula (I): R3_ (χ_R ₂ _γ) _n _χ_A-R ₁ -AX- (YR ₂ -X) _m -R ₃ (I) 0 to 70 mol% (limits included) of macromolecular chains having the following formula (II) in which -XY- is a radical resulting from the polycondensation of two reactive functions Fi and F ₂ such that - F! is the precursor of the radical -X- and F ₂ the precursor of the radical -Y- or vice versa, - the functions F ^ cannot react with one another by condensation - The F ₂ functions cannot react with one another by condensation - A is a covalent bond or an aliphatic hydrocarbon radical which can comprise heteroatoms and comprising from 1 to 20 carbon atoms. - R2 is a branched or unbranched aliphatic or aromatic hydrocarbon radical comprising from 2 to 20 carbon atoms. - R3. R4 represents hydrogen, a hydroxyl radical or a hydrocarbon radical - R- | is a hydrocarbon radical comprising at least 2 carbon atoms, linear or cyclic, aromatic or aliphatic and which can comprise heteroatoms. - n, m and p each represent a number between 50 and 500, preferably between 100 and 400. All the known polycondensation functions can be used in the context of the invention for Fi and F ₂ . According to a particular embodiment of the invention; the polymer matrix is a polyamide A1 consisting of: 30 to 100 mol% (limits included) of macromolecular chains corresponding to the following formula (I): R3- (XR ₂ -Y) nXAR ₁ -AX- (YR ₂ -X) _m -R ₃ (I) 0 to 70 mol% (limits included) of macromolecular chains corresponding to the following formula (II) R ₄ - [YR ₂ -X] _P -R ₃ (II) in which:

- Y is the radical - N - when X represents the radical - C -, R ₅ O

- Y is the radical - C - when X represents the radical N, OR ₅ - A is a covalent bond or an aliphatic hydrocarbon radical which may comprise heteroatoms and comprising from 1 to 20 carbon atoms.

- R2 is a branched or unbranched aliphatic or aromatic hydrocarbon radical comprising from 2 to 20 carbon atoms.

- R3, R4 represents hydrogen, a hydroxyl radical or a hydrocarbon radical

comprising a group fj or - N - k

- R5 represents hydrogen or a hydrocarbon radical comprising from 1 to 6 carbon atoms

- R- | is a hydrocarbon radical comprising at least 2 carbon atoms, linear or cyclic, aromatic or aliphatic and which can comprise heteroatoms. -n, m and p each represent a number between 50 and 500, preferably between 100 and 400.

According to another particular embodiment of the invention, the polymer matrix of the invention consists of a polyester A2 consisting of: - 30 to 100% molar (limits included) of macromolecular chains corresponding to the following formula (I): R _3. (χ.R ₂ .γ) _n .χ.AR ₁ -AX- (YR ₂ -X) _m -R3 (I) 0 to 70 mol% (limits included) of macromolecular chains corresponding to formula (II) next R ₄ - [YR ₂ -X] _P -R ₃ (H) in which:

- Y is the radical when X represents the radical - C - O

- Y is the radical - C - when X represents the radical O - A is a covalent bond or an aliphatic hydrocarbon radical which can comprise heteroatoms and comprising from 1 to 20 carbon atoms.

- R3, R4 represents hydrogen, a hydroxyl radical or a hydrocarbon radical

comprising a group ^ or O - R- _| is a hydrocarbon radical comprising at least 2 carbon atoms, linear or cyclic, aromatic or aliphatic and which can comprise heteroatoms. -n, m and p each represent a number between 50 and 500, preferably between 100 and 400. The polymer matrix of the invention can also be a copolyesteramide. Advantageously m, n and p are between 100 and 400, in particular between 100 and 300. m, n and p can for example be between 120 and 240. It should be noted that the values of m and n can be equal. The values m, n and p can also be equal. Advantageously, R2 is a pentamethylene radical. The polyamide A1 or the polyester A2 of the invention advantageously comprises at least 45%, preferably at least 60%, even more preferably at least 80 mol% of macromolecular chains corresponding to formula (I). The polyamide A1 or the polyester A2 of the invention advantageously has a number molecular mass at least equal to 10,000 g / mol, preferably at least equal to 20,000 g / mol, more preferably at least equal to 25,000 g / mol. By molecular weight by number of polyamide A1 or polyester A2, is meant the molecular weight by number weighted by the molar fractions of the two types of macromolecular chains of formulas (I) and (II). The yarns, fibers, filaments of the invention, comprising in their polymer matrix polyamide A1 and / or polyester A2, have good abrasion resistance properties. They are in particular suitable for the manufacture of felts for paper machines. The use of polyamide A1 or polyester A2 makes it possible to spin at a lower temperature and / or at reduced pressure compared to the conditions which would be necessary in the absence of polyamide A1 or polyester A2. It is thus possible either to obtain threads which resist abrasion better, or to obtain fibers whose properties are similar, with a less restrictive process (in particular in processing temperature or in spinning pressure). The yarns, fibers and filaments according to the invention can contain all the additives usually used with such polymers, for example thermal stabilizers, UV stabilizers, catalysts, pigments and dyes, antibacterial agents. According to a particular embodiment of the invention, the polyamide A1 or the polyester A2 is obtained by copolymerization from a mixture of monomers comprising: a) a difunctional compound whose reactive functions are chosen from amines, carboxylic acids , alcohols, and their derivatives, the reactive functions being identical, b) the monomers of general formulas (Nia) and (IIIb) below in the case of polyamide A1 OR ' ² \ N X'-R' ₂ -Y '( lll _a ) or H

b ') of the monomers of general formulas (IIIa') and (IIIb ¹ ) below in the case of polyester A2, 0 R '. ^ ² \ X'-R ' ₂ -Y' (lll _a ) or ° (lll _b ) in which R'2 represents an aliphatic, cycloaliphatic or aromatic hydrocarbon radical, substituted or not, comprising from 2 to 20 carbon atoms, and which can comprise heteroatoms,

• Y 'is an amino radical when X' represents a carboxylic radical, or Y 'is a carboxylic radical when X' represents an amino radical, in the case of polyamide A1

• Y 'is a hydroxyl radical when X' represents a carboxylic radical, or Y 'is a carboxylic radical when X' represents a hydroxyl radical, in the case of polyester A2 By carboxylic acid or carboxylic radical in the present invention, is meant the carboxylic acids and their derivatives, such as acid anhydrides, acid chlorides, esters, nitriles etc. By amine is meant amines and their derivatives. The monomers of formula (III _a ) or (III _b ) are preferably the polyamide monomers of the polyamide 6, polyamide 11, polyamide 12 etc. type. Examples of monomers of formula (III _a ) or (III) which may be suitable in the context of the invention include caprolactam, 6-aminocaproic acid, lauryllactam etc. It can be a mixture of different monomers. As examples of monomers of formula (III _a ') or (III _b ') which may be suitable in the context of the invention, mention may be made of caprolactone, δ-valerolactone, 4-hydroxybenzoic acid etc. The monomer mixture can also comprise a monofunctional monomer conventionally used in the production of polymers as chain limiter. The mixture of monomers can also include catalysts. During the monomer mixing operation, the various compounds of the mixture can be introduced in dried form, advantageously with a moisture content of less than 0.2%, preferably less than 0.1%, and a mixture can be added. compound capable of catalyzing the polycondensation of the polyamide or of the polyester, preferably in a concentration by weight of between 0.001% and 1%. The humidity can be measured according to the method of K. Fisher. These catalysts, preferably introduced in a concentration by weight of between 0.001% and 1%, can be chosen from phosphorous compounds, for example phosphoric acid, tris (2,4-d i-tert-buty I phenyl) phosphite ( marketed by the company CIBA under the reference Irgafos 168), pure or mixed with N, N- hexamethylene bis (3,5-di-tert-butyl-4-hydroxyhydrocinnamamide) (marketed by CIBA under the reference Irganox B 1171). Advantageously, the compound a) represents between 0.05 and 1 mol% relative to the number of moles of monomers of type b) or b '), preferably between 0.1 and 0.5 mol%. In the case of polyamide A1, the copolymerization of the monomers is carried out under conventional conditions for the polymerization of polyamides obtained from lactams or amino acids. In the case of polyester A2, the copolymerization of the monomers is carried out under conventional conditions for the polymerization of polyesters obtained from lactones or hydroxy acids. The polymerization can comprise a finishing step in order to obtain the desired degree of polymerization. According to another particular embodiment of the invention, the polyamide A1 or the polyester A2 is obtained by melt-blending, for example using an extrusion device, a polyamide of the type of those obtained by polymerization of lactams and / or amino acids or of a polyester of the type obtained by polymerization of lactones and / or hydroxy acids and of a difunctional compound whose reactive functions are chosen from amines, alcohols, acids carboxylic and their derivatives, the reactive functions being identical. The polyamide is, for example, polyamide 6, polyamide 11, polyamide 12, etc. The polyester is, for example, polycaprolactone, poly (pivalolactone), etc. The difunctional compound is added directly to the polyamide or the polyester in the melt. . Advantageously, the difunctional compound represents between 0.05 and 2% by weight relative to the weight of polyamide or polyester. During the operation of mixing the polyester or polyamide with the difunctional compound, the various compounds of the mixture can be introduced in dried form, with advantageously a moisture content of less than 0.2%, preferably less than 0.1 %, for example in an extrusion device and a compound capable of catalyzing the polycondensation of the polyamide or of the polyester can be added, preferably in a concentration by weight of between 0.001% and 1%. This compound can be chosen from phosphorous compounds, for example phosphoric acid, tris (2,4-di-tert-butyl phenyl) phosphite (sold by the company CIBA under the reference Irgafos 168), pure or in mixture with N, N-hexamethylene bis (3,5-di-tert-butyl-4-hydroxyhydrocinnamamide) (sold by CIBA under the reference Irganox B 1171). This compound can be added in powder form or in concentrated form in a polyamide matrix (masterbatch). The mixture of the different compounds can be implemented in a single or twin screw extrusion device. The difunctional compound of the invention is preferably represented by the formula (IV): X "-A-R1-AX". (IV) in which X "represents an amino radical, a hydroxyl radical or a carboxylic group or their derivatives R1 and A are as described above. As an example of radical X", there may be mentioned a primary amine radical , secondary amino etc. The difunctional compound can be a dicarboxylic acid. As examples of diacids, mention may be made of adipic acid which is the preferred acid, decanoic or sebacic acid, dodecanoic acid, phthalic acids such as terephthalic acid, isophthalic acid. It may be a mixture comprising by-products from the manufacture of adipic acid, for example a mixture of adipic acid, glutaric acid and succinic acid. The difunctional compound can be a diamine. As examples of diamines, mention may be made of hexamethylene diamine, methyl pentamethylenediamine, 4,4'-diaminodicyclohexylmethane, butane diamine, metaxylylene diamine. The difunctional compound can be a dialcohol. Examples of dialcohols that may be mentioned include 1,3-propanediol, 1,2-ethanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol and polytetrahydrofuran. The functional compound can be a mixture of a diamine and a dialcohol. In the case of polyamide A1, the reactive functions of the difunctional compound are generally amines or carboxylic acids or derivatives. In the case of polyester A2, the reactive functions of the difunctional compound are generally alcohols or carboxylic acids or derivatives. Preferably the difunctional compound is chosen from adipic acid, decanoic or sebacic acid, dodecanoic acid, terephthalic acid, isophthalic acid, hexamethylene diamine, methyl pentamethylenediamine, 4,4'- diaminodicyclohexylmethane, butane diamine, metaxylylene diamine, 1, 3-propanediol, 1, 2-ethanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol and polytetrahydrofuran According to another particular embodiment of the invention, the polyamide A1 or the polyester A2 is obtained by melt-blending, for example using an extrusion device, a polyamide of the type of those obtained by polymerization of lactams and / or amino acids or of a polyester of the type of those obtained by polymerization of lactones and / or hydroxy acid, with a compound of formula (V): GRG (V) in which R is a hydrocarbon radical, linear or cyclic, aromatic or aliphatic, substituted or not, and which can comprise heteroatoms, G being a function or a radical which can react selectively either with the reactive amino functions, or with the reactive alcohol functions, or with the reactive carboxylic acid functions of the polyamide or polyester, to form covalent bonds. The polyamide is for example polyamide 6, polyamide 11, polyamide 12. The polyester is for example polycaprolactone or poly (pivalolactone). The compound of formula (V) is added directly to the polyamide or polyester in a molten medium. Advantageously, the compound of formula (V) represents between 0.05 and 2% by weight relative to the weight of polyamide or polyester. During the operation of mixing the polyester or polyamide with the compound of formula (V), the various compounds of the mixture can be introduced in dried form, with advantageously a moisture content of less than 0.2%, preferably less at 0.1%, for example in an extrusion device and a compound capable of catalyzing the polycondensation of the polyamide or of the polyester can be added, preferably in a concentration by weight of between 0.001% and 1%. This compound can be chosen from phosphorous compounds, for example phosphoric acid, tris (2,4-di-tert-butyl phenyl) phosphite (sold by the company CIBA under the reference Irgafos 168), pure or in mixture with N, N-hexamethylene bis (3,5-di-tert-butyl-4-hydroxyhydrocinnamamide) (sold by CIBA under the reference Irganox B 1171). This compound can be added in powder form or in concentrated form in a polyamide matrix (masterbatch). The mixture of the different compounds can be implemented in a single or twin screw extrusion device. All the polymer chain couplers or the polymer chain extension agents known to a person skilled in the art, generally comprising two identical functions or two identical radicals, and reacting selectively either with the reactive amino functions or with the reactive alcohol functions, either with the reactive carboxylic acid functions of the polyamide or of the polyester, to form covalent bonds, can be used as compound of formula (V). In the case of obtaining polyamide A1, the compound (V) can for example selectively react with the amine functions of the polyamide into which it is introduced. This compound will not react with the acid functions of the polyamide in this case. The spun articles, threads, fibers or filaments are produced according to the usual spinning techniques from a composition comprising a polymer matrix comprising at least the polyamide A1 or the polyester A2 described above. Spinning can be carried out immediately after the polymerization of the matrix, the latter being in molten form. It can be produced from a granule comprising the composition. The articles spun according to the invention can be subjected to all the treatments which can be carried out in stages subsequent to the spinning stage. They can in particular be stretched, textured, crimped, heated, twisted, dyed, sized, cut ... These additional operations can be carried out continuously and can be integrated after the spinning device or be carried out discontinuously. The list of post-spinning operations has no limiting effect. The invention also relates to articles comprising yarns, fibers and / or filaments as described above. The yarns, fibers, filaments according to the invention can be used in woven, knitted or non-woven form. The fibers according to the invention are in particular suitable for the manufacture of felts for paper machines, and in particular for the nonwovens of felts for paper machines. The yarns, fibers and filaments according to the invention can also be used as yarns for carpets. They can also be used, in particular monofilaments, for obtaining fabrics in the field of screen printing for printing transfers, or in the field of filtration. The yarns, fibers, filaments of the invention, and in particular the multi-strands, can also be used in the manufacture of ropes, in particular climbing ropes, or of belts, in particular conveyor belts. Finally, the yarns of the invention can be used for the manufacture of nets, in particular fishing nets. Other details or advantages of the invention will appear more clearly in the light of the examples given below only for information.

Characterization tests:

• Content of terminal groups The contents of acid [COOH] and amino [NH ₂ ] terminal groups are determined by potentiometry. • Calculation of the molar ratios of chains corresponding to the formulas (I) and (II) previously described for the polymers of the invention In examples 1 to 3 below, the polymers consist of a mixture of: - corresponding linear chains to formula (II) and comprising 2 different ends per chain (COOH and NH ₂ ) - linear chains corresponding to formula (I) and comprising 2 identical ends per chain (2 times COOH) In this particular case, R ₃ is the hydroxyl radical and R ₄ is the hydrogen radical (as defined in the document) The molar levels of chains corresponding to formulas (I) and (II) are estimated according to the following formulas: molar level (I) = ([COOH] - [NH ₂ ]) / ([COOH] + NH ₂ ]) molar rate (II) = 2 * [NH ₂ ] / ([COOH] + NH ₂ ])

• Calculation of the molecular mass in number The molecular mass in number [M _N ] is estimated according to the following formulas: - in comparative examples A and the examples of the invention, which correspond to linear polymers (by linear polymer, we means a polymer consisting of macromolecular chains each having 2 ends), the conventional formula is used [M _N ] = 2. 10 ⁺⁶ / ([NH ₂ ] + [COOH]) - in Comparative Examples B, the polymer is a mixture of linear chains (2 ends per polymer chain) and 4-branched stars (4 ends per star polymer chain), therefore the formula established in patent WO 97/24388 is used: [M _N ] = 1. 10 ⁺⁶ / (Co + [NH ₂ ]) where Co = ([COOH] - [NH ₂ ]) / 4 represents the molar concentration of the tetrafunctional compound constituting the heart motif of stars (all the functions of the heart motif are identical: -COOH) In all these formulas, the concentrations [COOH], [NH ₂ ] and Co are expressed in μmol / g, the mass [M _N ] being expressed in g / mol.

• Normalization of the Pressure Drop in the pack (die head) In the various examples described below, a Pressure Drop (expressed in bars) is measured when crossing the pack (die head), composed of filtration elements and capillaries. However, depending on the nature of the polymer, it is necessary to adjust the temperature of the pack and the polymer. This has the effect of changing the value of the Pressure Drop. It is well known that the melted viscosity of polymers, or in this case, the Pressure Loss, varies with temperature according to an Arrhenius law, which allows for example, from experimental values (temperature Ti and Pressure Loss ΔP ^ to estimate the value of the Pressure Drop ΔP ₂ at another temperature, any, T ₂ . This calculation can also be extended to cases where the two spinning conditions also correspond to different flow rates (when the variation in absolute value IΔQ / Q | is less than 50%), respectively Q and Q ₂ : ΔP ₂ = Q ₂ / Q, x ΔP, x Exp [E x (1 / T ₂ - 1 / T,) / R] In this formula, Ti and T ₂ are expressed in degrees Kelvin, E the activation energy, expressed in J / mol and R is the constant of ideal gases (R = 8.31 J / mol / K).

In this formula, the flow rate Q can be measured, in a completely equivalent manner on several levels. The simplest is to measure the titer (the unit being the dtex, equal to the mass in g of 10000m of multifilament). Under these conditions, Q is easily obtained by writing: Q = t ^* v / 10000

In this formula, the flow rate Q is expressed in g / min, the titer t is expressed in dtex = g / 10000m and the speed v is expressed in m / min.

As all the tests were carried out with the same calling speed, it is therefore sufficient to replace in the previous formula the ratio of the flow rates Q ₂ / Qι by the ratio of the titles t ₂ / tι.

In the case of Polyamide, the activation energy E is equal to 60 kJ / mol (M.l. Kohan,

Nylon Plastics, page 140, ed. John Wiley & Sons, Inc., 1973).

In order to compare the different spinning conditions (J ΔP ^ of the examples detailed below, a standardization is carried out, that is to say that the pressure drop values ΔPi measured at Ti (variable of test to another) for a flow rate of Q ^ (product of the title in dtex by the speed in m / min, variable from one test to another), are all brought back to the same temperature T ₂ chosen equal to 250 ° C and at the same flow rate Q ₂ (equivalent to 200 dtex at 800 m / min) according to the above formula The values ΔP ₂ of the different examples can therefore be compared with one another.

• Abrasion resistance test Figure 1 schematically represents the apparatus used for the abrasion resistance test. The reference 1 represents the wire, the reference 2 a ceramic bar, the reference 3 a mass of 3g, the reference 4 of water. In this test, already described in the literature (conference "Abrasion Résistant PA fiber", Man-Made Fiber Congress, Dornbirn, Sept 2002), a unitary filament is subjected to a pre-tension of 3 g. The wire is immersed in a water bath at 23 ° C. The filament rubs against a ceramic rod with a diameter of 10mm, sold by the company Rothschild for the FFAB (“Felt Fiber Abrasion Tester”) test for surface roughness Ra = 1.7 μm, Rz = 8.9 μm and Rmax = 11.3 μm . The bar is rotating at 300 revolutions / minute with a contact angle of the wire on the bar (clamping) of 90 °. Before the test, the filament is first of all desensitized for 1 hour in a Soxhiet assembly in petroleum ether and then conditioned for 24 hours in a water bath at 25 ° C. The total number of turns is noted before the filament breaks. This number is divided by the unit title of the strand in order to get rid of the title of the strand which can vary from one test to another. In total, the experiment is repeated 30 times and the results are averaged.

Examples

Comparative Examples A = polyamide 6 Synthesis The polyamides 6 called A1, A2, A3 and A4 are synthesized. They have the following characteristics:

measurements performed a posteriori on the wire [M _N ] = 2. 10 1+ ^* 6 ° / ([NHJ + fCOOH]) Spinning These polyamides 6 are spun under the following conditions: - twin-screw extruder, - temperature adjusted in order to '' obtain satisfactory spinnability - 10-hole die - air cooling - call speed of 800 m / min - overall titer of the order of 200 to 240 dtex Under these temperature and flow conditions, a pressure drop is observed during the crossing of the “pack” (die block comprising the filtration elements and the capillaries). The following table specifies the raw values (temperature, titre, pressure drop) as well as the renormalized values, that is to say brought back to a temperature constant (250 ° C) and a constant flow (corresponding to a titer of 200dtex for a call speed of 800m / min). The renormalization is carried out in accordance with the formula previously described.

Drawing The drawing rate is adjusted so as to obtain, after drawing, the desired level of elongation at break: approximately 80%. The yarn thus obtained is always composed of 10 filaments.

Comparative Examples B = Polymer comprising star macromolecular chains Synthesis The star polyamides B1, B2, B3 are obtained by copolymerization from caprolactam in the presence of approximately 0.5 mol% of 2,2,6,6-tetra (β- carboxyethyl) cyclohexanone, according to a process described in document FR 2743077. They have the following characteristics:

measurements performed a posteriori on the wire [M] = 1. 10 ⁺⁶ / (([COOH] - [NH ₂ ]) / 4 + [NHJ) Spinning The yarn thus obtained is made up of 10 filaments with an overall titer of the order of 240 dtex. As before, these polymers are spun under conditions of temperature and flow such that there is good filability. Under these conditions, a pressure drop is observed which is normalized at constant temperature and flow rate, as above.

Drawing The drawing rate is adjusted so as to obtain, after drawing, the desired level of elongation at break. It is always composed of 10 filaments.

Examples 1-3 according to the invention Synthesis These polymers are obtained by polycondensation of caprolactam in the presence of adipic acid. They have the following characteristics:

measurements performed a posteriori on the wire [M _N ] = 2. 10 ⁺⁶ / ([NH ₂ ] + [COOH]) Spinning The strands thus obtained are always composed of 10 filaments with an overall titer of the order of 200dtex. As before, these polymers are spun under conditions of temperature and flow such that there is good filability. Under these conditions, a pressure drop is observed which is normalized at constant temperature and flow rate, as above.

Drawing The drawing rate is adjusted so as to obtain, after drawing, the desired level of elongation at break. It is always composed of 10 filaments. The unit titer is 9.9 dtex. Example 4: Measurement of the abrasion resistance Table 1 below presents the characteristics in terms of fluidity and abrasion resistance of the comparative examples A, B as well as of the examples in accordance with the invention.

Table 1

Figure 2 is a graph representing on the abscissa the pressure drop during the crossing of the pack (expressed in bars), and on the ordinate the abrasion resistance (expressed in cycle / dtex). In this Figure 2, polymers A are represented by diamonds, polymers B are represented by squares, and polymers 2-3 are represented by triangles.

It appears that for the polymers tested, the abrasion resistance is directly linked to the pressure drop (itself directly linked to the molecular mass). In other words, the improvement of this usage property is only possible at the expense of the increase in the pressure drop, that is to say the degradation of the processability. However, this pressure drop (or melt viscosity) cannot be infinitely increased without inducing thermal degradation of the polymer, for example. Compared to the correlation between abrasion resistance and pressure drop of Comparative Examples A, it appears that Comparative Examples B, obtained here by mixing with 4-pointed stars, result in a degradation of the compromise. On the other hand, the examples according to the invention result in an improvement in the compromise, that is to say in the possibility of obtaining higher abrasion resistance for the same processability.

Claims

1. Abrasion-resistant threads, fibers and filaments obtained from a composition comprising a polymer matrix, the polymer matrix consisting of a polycondensate consisting of: - 30 to 100% molar (limits included) of macromolecular chains corresponding to the formula (I) below: R ₃ - (XR ₂ -Y) _n -XAR ₁ -AX- (YR ₂ -X) _m -R ₃ (I) - 0 to 70 mol% (limits included) of macromolecular chains corresponding to the following formula (II) R ₄ - [YR ₂ -X] _P -R ₃ (II) in which -XY- is a radical resulting from the condensation of two reactive functions F ₁ and F ₂ such that - F _T is the precursor of the radical -X- and F ₂ the precursor of the radical -Y- or vice versa, - the functions F ^ cannot react with one another by condensation - the functions F ₂ cannot react with each other by condensation

- A is a covalent bond or an aliphatic hydrocarbon radical which may comprise heteroatoms and comprising from 1 to 20 carbon atoms.

- R2 is a branched or unbranched aliphatic or aromatic hydrocarbon radical comprising from 2 to 20 carbon atoms. - R3, R4 represents hydrogen, a hydroxyl radical or a hydrocarbon radical

- R-] is a hydrocarbon radical comprising at least 2 carbon atoms, linear or cyclic, aromatic or aliphatic and which may comprise heteroatoms.

- n, m and p each represent a number between 50 and 500.

2. Yarns, fibers and filaments according to claim 1, characterized in that the polymer matrix consists of a polyamide A1 consisting of: 30 to 100 mol% (limits included) of macromolecular chains corresponding to the following formula (I): R ₃ - (XR ₂ -Y) _n -XAR ₁ -AX- (YR ₂ -X) _m -R ₃ (I) - 0 to 70 mol% (limits included) of macromolecular chains corresponding to the following formula (II) R ₄ - [YR ₂ -X] _P -R ₃ (II) in which: - Y is the radical - N - when X represents the radical - C - R ₅ O - Y is the radical - C - when X represents the radical NOR ₅

\ - A is a covalent bond or an aliphatic hydrocarbon radical which may comprise heteroatoms and comprising from 1 to 20 carbon atoms. - R2 is a branched or unbranched aliphatic or aromatic hydrocarbon radical comprising from 2 to 20 carbon atoms. - R3, R4 represents hydrogen, a hydroxyl radical or a hydrocarbon radical

10 comprising a group ^ or - N - OR ₅ - R5 represents hydrogen or a hydrocarbon radical comprising from 1 to 6 carbon atoms - Ri is a hydrocarbon radical comprising at least 2 carbon atoms, linear or cyclic, aromatic or aliphatic and may include heteroatoms.

15 - n, m and p each represent a number between 50 and 500.

3. Yarns, fibers and filaments according to claim 1, characterized in that the polymer matrix consists of a polyester A2 consisting of: - 30 to 100 mol% (limits included) of macromolecular chains 20 corresponding to the following formula (I): R ₃ - (XR ₂ -Y) _n -XAR ₁ -AX- (YR ₂ -X) _m -R ₃ (I) - 0 to 70 mol% (limits included) of macromolecular chains corresponding to the following formula (II) R ₄ - [YR ₂ -X] _P -R ₃ (II) 25 in which: - Y is the radical when X represents the radical - C - O - O - - Y is the radical - C - when X represents the radical O - A is a covalent bond or an aliphatic hydrocarbon radical which can comprise heteroatoms and comprising from 1 to 20 carbon atoms.

30 - R2 is a branched or unbranched aliphatic or aromatic hydrocarbon radical comprising from 2 to 20 carbon atoms. - R3, R4 represents hydrogen, a hydroxyl radical or a hydrocarbon radical comprising a group ^- ^ or O

- R- _] is a hydrocarbon radical comprising at least 2 carbon atoms, linear or cyclic, aromatic or aliphatic and which may comprise heteroatoms.

- n, m and p each represent a number between 50 and 500.

4. Yarns, fibers and filaments according to one of the preceding claims; characterized in that n, m and p are between 100 and 300.

5. Yarns, fibers and filaments according to one of claims 2 to 4, characterized in that the polyamide A1 or the polyester A2 comprises at least 45%, preferably at least 60 mol% of macromolecular chains corresponding to the formula (I ).

6. Yarns, fibers and filaments according to one of claims 2 to 5, characterized in that the polyamide A1 or the polyester A2 has a number molecular mass at least equal to 25000 g / mol.

7. Yarns, fibers and filaments according to one of the preceding claims, characterized in that R2 is a pentamethylenic radical.

8. Yarns, fibers and filaments according to one of claims 2 to 7, characterized in that the polyamide A1 or the polyester A2 is obtained by copolymerization from a mixture of monomers comprising: a) a difunctional compound whose functions reactants are chosen from amines, carboxylic acids, alcohols, and their derivatives, the reactive functions being identical, b) the following monomers of general formulas (IIIa) and (IIIb) in the case of polyamide A1 -.OR ' ² \ N X'-R ' ₂ -Y' (lll _a ) or H

b ') of the monomers of general formulas (IIIa') and (IIIll ') below in the case of polyester A2 R ' ² \ X'-R'z-Y' (llla) or ° (lll _b ) in which

R'2 represents an aliphatic, cycloaliphatic or aromatic hydrocarbon radical, substituted or not, comprising from 2 to 20 carbon atoms, and which can comprise heteroatoms,

• Y 'is a hydroxyl radical when X' represents a carboxylic radical, or Y 'is a carboxylic radical when X' represents a hydroxyl radical, in the case of polyester A2.

9. Yarns, fibers and filaments according to claim 8, characterized in that the compound a) represents between 0.05 and 1 mol% relative to the number of moles of monomers of type b) or b ').

10. Yarns, fibers and filaments according to one of claims 2 to 7, characterized in that the polyamide A1 or the polyester A2 is obtained by melt-blending a polyamide of the type of those obtained by polymerization of lactams and or amino -acids or a polyester of the type of those obtained by polymerization of lactones and / or hydroxy acids with a difunctional compound whose reactive functions are chosen from amines, alcohols, carboxylic acids and their derivatives, the reactive functions being identical.

11. Yarns, fibers and filaments according to claim 10 characterized in that the difunctional compound represents between 0.05 and 2% by weight relative to the weight of polyamide or polyester.

12. Yarns, fibers and filaments according to one of claims 8 to 1 1, characterized in that the difunctional compound is represented by the formula (IV):

X "-AR AX" (IV) in which X "represents an amino radical, a hydroxyl radical, a carboxylic group or their derivatives.

13. Yarns, fibers and filaments according to one of claims 8 to 12, characterized in that the difunctional compound is chosen from adipic acid, decanoic or sebacic acid, dodecanoic acid, terephthalic acid, l isophthalic acid, hexamethylene diamine, methyl pentamethylenediamine, 4,4'- diaminodicyclohexylmethane, butane diamine, metaxylylene diamine, 1, 3-propanediol, 1, 2-ethanediol, 1, 4-butanediol, 1,5-pentanediol, 1,6-hexanediol and polytetrahydrofuran.

14. Yarns, fibers and filaments according to one of claims 2 to 7, characterized in that the polyamide A1 or the polyester A2 is obtained by melt-blending, a polyamide of the type of those obtained by polymerization of lactams and / or amino acids or of a polyester of the type of those obtained by polymerization of lactones and / or hydroxy acids, with a compound of formula (V): GRG (V) in which

R is a hydrocarbon radical, linear or cyclic, aromatic or aliphatic, substituted or not, and which can comprise heteroatoms,

• G being a function or a radical which can react selectively either with the reactive amino functions, or with the reactive alcohol functions, or with the reactive carboxylic acid functions of the polyamide or of the polyester, to form covalent bonds.

15. Yarns, fibers and filaments according to claim 14, characterized in that the compound of formula (V) represents between 0.05 and 2% by weight relative to the weight of polyamide or polyester.

16. Article comprising yarns, fibers and / or filaments according to one of claims 1 to 15.

17. Article according to claim 16, characterized in that it is a felt for a paper machine.

18. Article according to claim 16, characterized in that it is a carpet or a carpet.

19. Article according to claim 16, characterized in that it is a rope or a strap.

20. Article according to claim 16, characterized in that it is a fabric for printing transfer or for filtration.

21. Article according to claim 16, characterized in that it is a net.