FR2857017A1 - Use of zinc sulfide as a delustering additive in thermoplastic polymer compositions, e.g. polyamide-based compositions for the production of fibers and flock-finish fabrics - Google Patents

Abstract

The use of zinc sulfide (I) as a delustering additive in thermoplastic polymer compositions involves incorporating (I) in amounts of more than 1.5 wt% based on the total weight of the composition. Independent claims are also included for: (1) thermoplastic polymer compositions containing more than 2.5 wt% (I), with a dullness greater than that of similar compositions containing the same amount of titanium dioxide instead of (I); (2) articles obtained from these compositions; and (3) highly matt, flock-finish surfaces comprising such articles.

Description

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 The present invention relates to a new use of zinc sulfide, as an agent for improving the dullness of thermoplastic polymer compositions. The invention also relates to thermoplastic polymer compositions comprising zinc sulfide as an additive, as well as yarns, fibers, filaments and articles made from these compositions.

Thermoplastic polymers have been widely used for many years, especially in the textile field in the form of yarns, fibers and filaments, as substitutes for natural products, because of the lower availability and / or higher cost of these latter.

However, the substitution of natural products by thermoplastic polymers causes differences in the quality of the finished products, in terms of mechanical resistance, chemical resistance, touch, appearance, etc.

While much progress has already been made with regard to mechanical and chemical resistance aspects, it is often objected by the end consumer to an excessive gloss of the thermoplastic polymers, especially when they are in the form of fibers, with respect to their natural counterparts.

This is why, for many years, it is sought to matify as much as possible compositions based on thermoplastic polymers, that is to say give them a more matte, or even less brilliant.

The prior art provides numerous methods for improving the mattness of thermoplastic polymers and it is known in particular that the incorporation of inorganic fillers such as titanium dioxide (TiO 2) in synthetic fibers, for example polyamide or polyester , can lead to dullness indices that are relatively satisfactory, even acceptable for most uses.

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Indeed, among the additives that can impart a high degree of dullness to a thermoplastic polymer composition, titanium dioxide now seems to be the one offering the best dullness index, with an equal quantity of additives. To further increase the dullness of thermoplastic polymer compositions and especially polyamides, it could be envisaged to increase the level of titanium dioxide in the polymer composition.

However, it can be seen that an increase in the amount of titanium dioxide causes only a very slight increase in the dullness, and above all, with relatively high levels of titanium dioxide, the physical characteristics of the polymer compositions thermoplastics and their processability tend to decrease significantly.

In addition to the deterioration of mechanical properties and poorer processability, an increase in the amount of fillers in polymer compositions also has the disadvantage of significantly increasing the cost of the finished product.

There remains therefore a need for thermoplastic polymers having a greater mattness than those known from the prior art, and whose weight percentage of mattifying additive is compatible with the desired applications and with processability and physical characteristics.

The literature provides numerous examples of thermoplastic polymers comprising various mineral fillers, which make it possible to impart to said polymers flameproofing, fluorescence, opacity, whitening, dullness, porosity, etc. properties.

Thus, US Pat. No. 6,071,612 discloses polyester yarns, fibers or filaments comprising zinc sulphide in proportions of between 0.1% and 3% by weight, making it possible to improve the whiteness and feel of polyester compositions. It is known that polyester-based compositions have a tendency to turn yellow and it is precisely desired to increase the whiteness of these compositions.

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It is thus demonstrated that zinc sulphide increases the whiteness of polyester compositions, whiteness expressed in terms of luminescence. This notion of whiteness, however, is unrelated to the matte aspect that is sought in the present patent application. The skilled person knows how to appreciate and differentiate the more or less matte aspect of two similar "whites".

Patent application WO-A1-99 / 67451 teaches that the addition of zinc sulphide, instead of titanium dioxide, in a thermoplastic polymer composition makes it possible to significantly reduce the abrasion of the blades of the knives used to cut fibers for flocking. The amount of zinc sulfide added to the polymer composition is 1.5% by weight in the examples. This amount is presented as sufficient to obtain a similar dullness to the same polymer loaded at 1.5% by weight of TiO 2.

Thus, a first object of the present invention is to provide mineral fillers to obtain an improved dullness of thermoplastic polymer compositions.

Another object of the present invention is to provide mineral fillers to obtain an improved dullness of thermoplastic polymers, compared to the dullness obtained with an equal amount of TiO 2 alone. Still other objects will become apparent from the detailed description of the invention which follows.

The inventors have surprisingly found that the above-mentioned objectives can be achieved in whole or in part by using, as an additive in thermoplastic polymer compositions, zinc sulfide (ZnS) in order to improve the dullness of said polymer compositions.

More specifically, the invention relates first of all to the use of zinc sulphide as an additive in thermoplastic polymer compositions, for improving the mattness of said compositions, characterized in that the zinc sulphide is present in an amount greater than 1, 5% by weight of the total mass of the thermoplastic polymer composition.

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In the present description, the term "dullness" should be understood as the opposite or opposing term "gloss".

Zinc sulphide is generally in the form of small particles, preferably micron, or less than one micron. The size of the zinc sulphide particles must indeed remain compatible with the constraints of implementation of the thermoplastic polymer compositions and especially for the preparation of son, fibers, filaments.

In addition, the zinc sulfide particles may advantageously be coated or coated, for example to protect them against various chemical or physical attacks, or to make them inert vis-à-vis the various components in which they are incorporated. The coating or coating agent will be chosen from agents known to those skilled in the art, and will furthermore not have to interfere with the intrinsic properties of dullness of zinc sulphide.

It may also be advantageous to use zinc sulphide coated or coated on a support which will preferably be inorganic, such as for example silica, alumina, etc.

According to the present invention, zinc sulfide is used as a matting agent, and in this respect is used as an additive in polymeric compositions, in particular in thermoplastic polymer compositions, for example as those used in the textile field for the production of yarns, fibers, filaments and textile articles, but also in many other fields where we seek the mattness of polymer compositions implemented by rolling, pultrusion, extrusion, extrusion blow molding, etc. .

Zinc sulphide as matting agent can advantageously be used as an additive, for example in sizing formulations of yarns, fibers and filaments, etc.

According to a particular embodiment of the invention, the proportion by weight of zinc sulphide relative to the total weight of the polymer composition is greater

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 1.5%, preferably greater than or equal to 2%, more preferably greater than or equal to 2.5% by weight.

For reasons of chemical, physical and mechanical properties, the proportion by weight of zinc sulphide relative to the total weight of the polymer composition is less than 10%, preferably less than 7%, advantageously less than 4% by weight.

The thermoplastic polymer composition within the meaning of the present invention comprises a thermoplastic polymer matrix composed of one or more thermoplastic polymers. It should be understood, however, that any polymer matrix known to those skilled in the art can be implemented within the scope of the present invention.

As examples of thermoplastic polymers that may be suitable as polymer matrix in the context of the present invention, mention may be made of: polylactones such as poly (pivalolactone), poly (caprolactone) and polymers of the same family; polyurethanes obtained by reaction between diisocyanates such as 1,5-naphthalene diisocyanate; p-phenylene diisocyanate, m-phenylene diisocyanate, 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 3,3-dimethyl 4,4'-biphenyl diisocyanate, 4,4'-diphenylisopropylidene diisocyanate, 3,3'-dimethyl-4,4'-diphenyl diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, dianisidine diisocyanate, toluidine diisocyanate, hexamethylene diisocyanate, 4,4'-diisocyanatodiphenylmethane and compounds of the same family and long-chain linear diols such as poly (tetramethylene adipate), poly (ethylene adipate), poly (1,4-butylene adipate), poly (ethylene succinate), poly (2,3-butylene succinate), polyether diols and compounds of same family; polycarbonates such as poly [methane-bis (4-phenyl) carbonate], poly [1,1-bis (4-phenyl) carbonate), poly [diphenylmethane-bis (4-phenyl) carbonate], poly [1,1cyclohexane-bis (4-phenyl) carbonate] and polymers of the same family; polysulfones; polyethers; polyketones; polyamides such as poly (4-aminobutyric acid), poly (hexamethylene adipamide), poly (6-aminohexanoic acid), poly (m-xylylene adipamide), poly (p-xylylene sebacamide), poly (2.2 , 2-

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 trimethylhexamethylene terephthalamide), poly (metaphenylene isophthalamide), poly (p-phenylene terephthalamide), and polymers of the same family; polyesters such as poly (ethylene azelate), poly (ethylene-1,5-naphthalate), poly (1,4cyclohexane dimethylene terephthalate), poly (ethyleneoxybenzoate), poly (para-hydroxybenzoate), poly (1, 4-cyclohexylidenedimethylene terephthalate), poly (1,4cyclohexylidene dimethylene terephthalate), polyethylene terephthalate, polybutylene terephthalate and polymers of the same family; poly (arylene oxides) such as poly (2,6-dimethyl-1,4-phenylene oxide), poly (2,6-diphenyl-1,4-phenylene oxide) and polymers of the same family; poly (arylene sulfides) such as poly (phenylene sulfide) and polymers of the same family; polyetherimides; vinyl polymers and their copolymers such as polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride, polyvinylbutyral, polyvinylidene chloride; ethylene-vinyl acetate copolymers, and polymers of the same family; acrylic polymers, polyacrylates and their copolymers such as poly (ethyl acrylate), poly (n-butyl acrylate), poly (methyl methacrylate), poly (ethyl methacrylate), poly (methacrylate) n-butyl), poly (n-propyl methacrylate), poly (acrylamide), poly (acrylonitrile), poly (acrylic acid); ethylene-acrylic acid copolymers, ethylene-vinyl alcohol copolymers, acrylonitrile copolymers, styrene methyl methacrylate copolymers, ethylene-ethyl acrylate copolymers, methacrylatebutadiene-styrene copolymers, ABS, and polymers from the same family; polyolefins such as low density poly (ethylene), polypropylene, low density chlorinated poly (ethylene), poly (4-methyl-1-pentene), poly (ethylene), poly (styrene), and polymers of the same family; ionomers; poly (epichlorohydrins); poly (urethane) s such as diol polymerization products such as glycerin, trimethylol propane, 1,2,6-hexanetriol, sorbitol, pentaerythritol, polyether polyols, polyester polyols and compounds of the same family with polyisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, 4,4'-dicycohexylmethane diisocyanate and compounds of the same family; and polysulfones such as the reaction products between a sodium salt of 2,2-bis (4hydroxyphenyl) propane and 4,4'-dichlorodiphenylsulfone; furan resins such as poly (furan); cellulose-ester plastics such as cellulose acetate, cellulose acetate butyrate, cellulose propionate and polymers of the same

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 family silicones such as poly (dimethylsiloxane), poly (dimethylsiloxane cophenylmethylsiloxane), and polymers of the same family; and mixtures of at least two of the foregoing polymers.

According to a particular variant of the invention, the thermoplastic matrix is a polymer comprising star or H macromolecular chains, and optionally linear macromolecular chains. The polymers comprising such star or H 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.

According to another particular variant of the invention, the thermoplastic matrix of the invention is a random tree-type polymer, preferably a copolyamide having a random tree structure. These copolyamides of random tree structure and their method of production are described in particular in WO 99/03909.

The thermoplastic matrix as defined in the present invention may also be a composition comprising a linear thermoplastic polymer and a thermoplastic star, H and / or tree polymer as described above.

For the purposes of the present invention, the thermoplastic polymer compositions may also comprise a hyperbranched copolyamide of the type of those described in WO 00/68298. Of course, the compositions cited in this specification may also include any combination of thermoplastic star polymer, H, tree, hyperbranched copolyamide described above.

As another type of polymer matrix that may be used in the context of the invention, there may be mentioned thermostable polymers: these polymers are preferably infusible or have a softening point greater than 180 ° C., preferably greater than or equal to 200 ° C. C or higher.

These thermostable polymers may, for example, be chosen from aromatic polyamides, polyamide imides such as polytrimellamide-imides, or polyimides, such as the polyimides obtained according to the document EP 0119185, known from

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 in trade under the P84 brand. The aromatic polyamides may be as described in patent EP 0360707. They may be obtained according to the process described in patent EP 0360707.

Among the polymer matrices, polyamide-based matrices, and in particular semicrystalline polyamides, such as polyamide 6, polyamide 6.6, polyamide 11, polyamide 12, polyamide 4, polyamides 4, are particularly preferred. 6.6-10, 6-12.6-36, 12-12, semi-aromatic polyamides obtained from terephthalic and / or isophthalic acid such as the polyamide marketed under the trade name AMODEL; polyesters such as PET, PBT, PTT; polyolefins such as polypropylene, polyethylene; aromatic polyamides, polyamide imides or polyimides; latex such as acrylic latex and urethane; PVC, viscose, cellulose, cellulose acetate; their copolymers and alloys.

The thermoplastic polymer compositions may furthermore contain all the other additives which may be used, for example reinforcing fillers, flame retardants, UV stabilizers, heat stabilizers, as well as other matting agents, such as, for example, titanium, barium sulfate, silica, calcium carbonate, calcium sulphate, alumina oxide, kaolin, clays and the like.

Another object of the present invention is the process for preparing thermoplastic polymer compositions comprising zinc sulfide as a matting agent. The zinc sulfide may be added to the polymer composition by any means known to those skilled in the art. Among these, however, the addition of zinc sulphide by feed into the molten stream of the matrix or of the polymer composition, or else by means of a masterbatch in English, is preferred.

In another aspect, it may also be envisaged, or even appropriate, to combine the latter two modes of feeding, molten-vein feed and masterbatch.

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The masterbatch will be prepared such that it contains a quantity of zinc sulfide of between 10% and 60% by weight, preferably between 20% and 50% by weight, advantageously between 30% and 40% by weight.

The compositions of thermoplastic polymers comprising zinc sulphide in an amount of more than 2.5% by weight as matting agent and as defined above, are new and as such also form another object of the present invention. Such compositions comprise at most 8% by weight of zinc sulphide, more particularly at most 6% by weight, advantageously at most 4% by weight.

It has thus been found that thermoplastic polymer compositions comprising more than 1.5% by weight of zinc sulphide exhibit a higher mattness compared to the same thermoplastic polymer compositions in which the zinc sulphide has been replaced by titanium dioxide in a quantity equal.

The present invention also relates to the articles and in particular the son, fibers and filaments obtained from the compositions described above. Indeed, the compositions according to the invention can be shaped molded articles, for example by injection or extrusion. They can also be shaped into threads, fibers and filaments by spinning.

In the case of yarns, fibers and filaments, these can be obtained for example by melt spinning, or by wet spinning, compositions of the invention. The compositions are then preferably prepared by introducing the zinc sulfide into the molten polymer in a mixing device, for example upstream of a spinning device. They can also be carried out by introducing zinc sulphide into a polymer solution, for example upstream of a wet spinning device.

By spinning the compositions of the invention, it is possible to obtain, for example, continuous multifilament yarns, short or long fibers, monofilaments, fiber yarns, plies, ribbons, cables, etc. It can also be son

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 continuous bulking agents (BCF: "Bulk Continuous Filament"), used in particular for the manufacture of textile coatings, such as carpets and rugs.

All conventional textile treatments can be applied to the yarns, fibers and filaments of the invention, such as stretching, texturing, dyeing, etc. In the field of yarns, fibers, textile filaments, the small size of the zinc sulphide particles-of the order of one micrometer, or even less than one micrometer, for example of the order of 0.3 μm-is an advantage in the spinning processes in particular.

The invention also relates to articles obtained from the yarns, fibers, filaments described above. Such articles can be obtained in particular from a single type of yarn, fibers, filaments or on the contrary from a mixture of yarns, fibers, filaments of different types. The article comprises at least in part threads, fibers, filaments according to the invention. For a given type of yarn, fibers, filaments-for example, yarns, fibers, filaments not containing zinc sulphide-yarns, fibers or filaments of different natures can be used in the article of the invention.

Examples of articles are woven, non-woven and knitted articles. The present invention also relates to composite articles, i.e. multi-component articles. These components may be for example short fibers, supports, articles, for example textile articles obtained from yarns, fibers, filaments such as nonwoven articles, etc.

As composite textile articles, there may be mentioned for example flocked surfaces whose main components are generally short fibers, an adhesive or an adhesive, and a support. The tufted surfaces used in particular in carpets, upholstery or wall coverings, etc., whose main components are generally yarns, fibers, filaments or articles obtained from yarns, fibers, filaments, a support, may also be mentioned. and possibly an adhesive or glue.

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In a flocked surface for example, the zinc sulfide present in the fibers of the flocked surface may also be present in the adhesive or adhesive used for flocking and / or in the support of the flocked surface.

The compositions, articles, textile articles, yarns, fibers and filaments, possibly composites, can be used in the manufacture of any product for which a high dullness is desired, in particular a higher dullness than hitherto observed by use. titanium dioxide, or even greater dullness undisclosed at the date of the present invention.

The thermoplastic polymer compositions according to the present invention find a particularly advantageous use in the preparation of flocked surfaces having a very high dullness.

Other details and advantages of the invention will appear more clearly in the light of the examples given below, which are only indicative.

EXAMPLES Preparation of samples of polyamide 6. 6 son added ZnS or TiO2. a) Sample preparation
Two sets of polyamide-based samples, one containing ZnS, the other containing TiO 2, are prepared with respective amounts of 1.4%, 2.5% and
3.5% by weight of matting agent, relative to the total weight of the composition, in each series.

 The polyamide 66 (PA66) used is a polyamide 66 not comprising titanium dioxide, of relative viscosity (measured at a concentration of 10 g / l in 96% sulfuric acid) of 2.6.

 The ZnS used (marketed by Sachtleben) has a particle size centered around 0.35 m.

 The TiO 2 used is sold under the name 1074 by Kronos.

 Incorporation of the matting agent (ZnS or TiO 2) into PA66 is: either by mixing the matting agent in powder form with the ground polymer;

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- or via a masterbatch (MM) based on polyamide comprising
30% by weight of matting agent, then mixing PA66 with the masterbatch, the PA66 and the MM each being in the form of granules.

In each case, the mixture is introduced into an extrusion device which provides the melt mixing. As indicated above, the incorporation rate of ZnS is 1.4%, 2.5% or 3.5% relative to the total weight of the composition for the ZnS loaded sample series and the rate of incorporation. TiO 2 incorporation is 1.4%, 2.5% or 3.5% for the control sample series. b) Preparation for spinning
The molten mixture is then spun with a die head temperature of about 285 ° C, air-cooled (20 C, 65% relative humidity), called with a winding speed of 800 m / min so as to obtain a wire continuous multifilament. This multifilament continuous yarn is stretched to obtain an elongation at break of the order of 80%. The multifilament or yarn thus obtained consists of 20 strands and the diameter of the strand is about 20 m.

 The die used is a die with 20 holes, of round section.

 The title on the end product is 2.3 dtex.

Description of the visual evaluation test of the mattness of the flocked surfaces. a) Preparation of a flocked surface
Six flocked surfaces are prepared using each of the samples obtained previously (3 with ZnS at 1.4%, 2.5% and 3.5% and 3 with TiO 2 at 1.4%, 2.5% and 3%. , 5%).

 The continuous yarns are cut into fibers 1 mm long. The fibers are subjected to an activating treatment based on tannin / aluminum sulphate.

 The fibers are then flocked onto a black polyester / cotton fabric (A4 format substrate) coated with Tubvinyl 235SL adhesive + 4% by weight Tubassist Fix 102W (marketed by the company CHT) over a thickness of 15 / 100th mm.

 The flocked surface thus obtained is then dyed in a full bath with 3% by weight relative to the weight of the Irganan Black RBLN fibers (marketed by CIBA).

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b) Assessment of the dullness
Maturity is visually assessed by a panel of a determined group of at least 7 people (controllers).

 Each test is carried out by comparative evaluation of the flocked surfaces, placed on a black cloth roll, outdoors and in sunny weather.

 The surfaces presented in front of the controllers are devoid of any distinctive marks likely to influence the evaluation.

 The dullness is evaluated by comparing two by two the flocked surfaces obtained with the fibers comprising identical rates of matting agent, one containing ZnS, the other TiO 2.

The results obtained are presented in the following Table (1):
Table (1) Evaluation of the dullness

<Tb>
<tb>% <SEP> in <SEP> weight <SEP> of <SEP> ZnS <SEP> in <SEP><SEP> fibers <SEP> 1,4 <SEP> 2,5 <SEP> 3,5
<tb> Matte <SEP> + <SEP> ++
<Tb>
-: indicates a dullness much lower than that observed for the flocked surface containing the same level of TiO 2.

 -: indicates a dullness lower than that observed for the flocked surface containing the same level of TiO 2.

 0: indicates a dullness similar to that observed for the flocked surface containing the same level of TiO 2.

 +: indicates a dullness greater than that observed for the flocked surface containing the same level of TiO 2.

 ++: indicates a dullness much higher than that observed for the flocked surface containing the same rate of TiO2.

 Reading these results indicates that at a low level (1.4% ZnS), the dullness is much lower than that obtained using titanium dioxide.

 On the other hand, at higher levels which correspond to the subject of the present invention, a higher dullness (2.5% of ZnS) is observed, or even much higher (3.5%) than that observed for the flocked surfaces obtained. with fibers containing the same levels of titanium dioxide (2.5% and 3.5% respectively).

Claims (12)

 1. Use of zinc sulphide as an additive in thermoplastic polymer compositions, for improving the mattness of said compositions, characterized in that the zinc sulphide is present in an amount greater than 1.5% by weight of the total mass of the thermoplastic polymer composition. 2. Use according to claim 1, wherein the zinc sulfide is present in an amount greater than or equal to 2%, preferably greater than or equal to 2.5% by weight relative to the total weight of the polymer composition. Use according to claim 1 or claim 2, wherein the zinc sulfide is present in an amount of less than 10%, preferably less than 7%, preferably less than 4% by weight. Use according to any one of the preceding claims wherein the thermoplastic polymer composition comprises a thermoplastic polymer matrix composed of one or more thermoplastic polymers. 5. Use according to any one of the preceding claims, in which the thermoplastic polymer composing the thermoplastic matrix of the polymer composition is chosen from polylactones, polyurethanes, polycarbonates, polysulfones, polyethers, polyketones, polyamides, polyesters, poly (arylene oxides), poly (arylene sulfides), polyetherimides, vinyl polymers and copolymers thereof, ethylene-vinyl acetate copolymers, acrylic polymers and copolymers, polyacrylates and copolymers thereof, polyolefins, ionomers, poly (epichlorohydrins), poly (urethane) s, polysulfones, furan resins, cellulose-ester plastics, silicones and mixtures of at least two of the foregoing polymers. <Desc / Clms Page number 15> 6. Use according to any one of the preceding claims, wherein the thermoplastic polymer composing the thermoplastic matrix of the polymer composition is a polyamide. 7. Use according to any one of the preceding claims, wherein the thermoplastic polymer comprising the thermoplastic matrix of the polymer composition is a polyamide chosen from polyamide 6, polyamide 6. 6, polyamide 11, polyamide 12, polyamide. 4, 4-6,6-10, 6-12,6-36, 12-12 polyamides, and semi-aromatic polyamides obtained from terephthalic and / or isophthalic acid. 8. A thermoplastic polymer composition comprising more than 2.5% by weight of zinc sulphide and having a higher dullness with respect to the same thermoplastic polymer composition in which the zinc sulphide has been replaced by an equal amount of titanium dioxide. The composition of claim 8 wherein the thermoplastic polymer comprises a polyamide matrix. An article obtained from one or more thermoplastic polymer compositions prepared using zinc sulfide according to any one of claims 1 to 7 or from one or more compositions according to claim 8 or claim 9. 11. Article according to claim 10 in the form of fibers son, fibers or filaments. 12. flocked surface of high dullness comprising one or more articles as defined in claim 11.