WO2005097880A1

WO2005097880A1 - Method for producing a polymer thermoplastic matrix

Info

Publication number: WO2005097880A1
Application number: PCT/FR2005/000689
Authority: WO
Inventors: Thierry Charbonneaux
Original assignee: Nylstar Sa
Priority date: 2004-03-23
Filing date: 2005-03-22
Publication date: 2005-10-20
Also published as: FR2868077A1; BRPI0508774A; EP1756209A1; CN1950435A; FR2868077B1

Abstract

The invention relates to a method for producing a polymer thermoplastic matrix by adding a ZnS-containing suspension during polymerisation of said polymer matrix. Products obtainable by forming said polymer matrix such as yarns, fibres, filaments, films and moulded articles are also disclosed.

Description

Method for manufacturing thermoplastic polymer matrix

The present invention relates to a process for manufacturing a thermoplastic polymer matrix by adding a suspension containing ZnS during the polymerization of said polymer matrix. The invention also relates to various articles obtained by shaping this polymer matrix, such as threads, fibers, filaments, films and molded articles.

The Applicant has developed a process for manufacturing a thermoplastic polymer composition by adding a suspension containing at least ZnS (zinc sulfide) during the polymerization of said polymer matrix. The process of the invention notably makes it possible to obtain a very good dispersion and distribution of the ZnS in the thermoplastic polymer. Furthermore, the introduction of ZnS into the synthesis makes it possible to avoid the formation of ZnS agglomerates in the polymer matrix which gives rise to certain problems of degradation during the manufacture of the polymer and / or of its shaping, in particular in the textile field. Indeed, the introduction of ZnS to the synthesis allows good dispersion of the ZnS particles in the matrix which avoids the obstruction of the die holes and the filtration media. This previously led to an increase in the pressure of the spinning packs and the breakage of the yarns, fibers and / or filaments obtained. ZnS also has the advantage of being inert and of not reacting with the polymer matrix. Thus, ZnS does not cause problems of degradation, coloring, yellowing of the articles obtained. Furthermore, the latter are not abrasive. ZnS also makes it possible to satisfy the desired properties in terms of cost, ease of implementation and introduction into polymeric matrices, such as thermoplastic matrices. Zinc sulfide also has the advantage of being a good mattifying agent.

The Applicant has also demonstrated that articles of the invention comprising ZnS in their thermoplastic polymer matrix by introduction to the polymerization according to the invention have excellent anti-mite, anti-bacterial and anti-fungal properties; these properties being effective even after various washes of said articles.

The present invention firstly relates to a process for the manufacture of a composition based on a thermoplastic polymer matrix containing at least ZnS, characterized in that a suspension containing, before or during the polymerization of said polymer matrix, is introduced. less than ZnS.

The present invention also relates to a thermoplastic polymer matrix capable of being obtained by the process described above. The thermoplastic polymer matrix can be chosen from the group comprising: polyamides; polyesters; polyvinyls; polyvinyl chlorides; polyvinyl acetates; polyvinyl alcohols; acrylic polymers such as PMMA, SAN, ABS copolymers; polyolefins such as polyethylene, polypropylene and polybutylene; cellulose derivatives such as cellulose acetate, cellulose-ester plastics; polyurethanes; their copolymers and / or mixtures.

As thermoplastic polymer, polyamides are particularly preferred, such as polyamide 6, polyamide 6.6, polyamide 11, polyamide 12; and polyesters, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), their copolymers and / or mixtures thereof.

As preferred polymers of the invention, there may be mentioned semi-crystalline or amorphous polyamides and copolyamides, such as aliphatic polyamides, semi-aromatic polyamides and more generally, linear polyamides obtained by polycondensation between a saturated aliphatic or aromatic diacid, and a diamine aromatic or aliphatic saturated primer, the polyamides obtained by condensation of a lactam, an amino acid or the linear polyamides obtained by condensation of a mixture of these different monomers. More specifically, these copolyamides can be, for example, the polyadipamide of hexamethylene, the polyphthalamides obtained from terephthalic and / or isophthalic acid, the copolyamides obtained from adipic acid, hexamethylene diamine and caprolactam. The compositions are preferably based on polyamide 6, polyamide 66, mixtures and copolymers based on these polyamides. It may in particular be a polyamide 6.6 / 6 copolymer. According to a particular variant of the invention, the thermoplastic matrix can comprise a polymer of star, tree or dendrimer type, in particular those comprising branched macromolecular chains and, where appropriate, linear macromolecular chains.

The polymer matrix can also comprise additives generally used in the field, which can be, for example reinforcing or filling fillers, flame retardants, UV stabilizers, heat stabilizers, pigments and lubricants.

Many methods of polymerizing thermoplastic polymer matrices known to those skilled in the art can be used according to the present invention. These methods include specificities depending on the polymer matrix which it is desired to obtain. Said suspension comprising ZnS is preferably introduced into the polymerization medium before the polymerization has properly started or when the polymerization has already started, in particular when the polymer has a low degree of polycondensation. For the manufacture of polyamide 66, the polymerization can comprise, according to the standard method, a step of concentration of salt N and a polycondensation step comprising the following phases: a phase of distillation under pressure, a decompression phase, a finishing phase and optionally an extrusion or shaping phase. The suspension containing ZnS is preferably added during the distillation phase under pressure.

For the manufacture of polyamide 6, the polymerization can comprise a step of mixing the molten caprolactam with water and optionally chain limiters, a step of heating, optionally a step of increasing the pressure followed by a step of decompression, possibly a vacuum finishing step, an extraction step, and a drying step. In the case of polyamide 6, the suspension containing ZnS is preferably added during the initial stage of mixing the molten caprolactam with water and optionally chain limiters. For the manufacture of polyester, the polymerization can comprise a mixing step, a transesterification or esterification step, optionally a concentration step, and a polycondensation step under vacuum. In the case of polyester, the suspension containing ZnS is preferably added before or just before the polycondensation phase.

The suspension of the invention may comprise, in addition to the ZnS, water and / or at least one compound chosen from the group comprising: surfactants, organic solvents and / or monomers of polymeric matrix. Particularly preferred is a suspension comprising at least ZnS, water and a surfactant.

The suspension is called aqueous suspension when it mainly comprises water. An aqueous suspension can also include one or more other compounds mentioned above. One can also use suspensions not comprising water, but another liquid, such as for example an organic solvent and / or a polymer matrix monomer, such as ethylene glycol.

The suspension can thus comprise surfactants, such as anionic surfactants (polyphosphates, alkyl esters sulfonates, alkyl sulfates, alkylamide sulfates, salts of saturated or unsaturated fatty acids, etc.), nonionics (polyalkoxy derivatives of alkylphenols, d fatty acids, amines, fatty acid amides, amidoamines, ethylene or propylene oxide condensates with ethylenediamine, alkylpolyglucosides ...), amphoterics (alkylamphoacetates ...) or zwitterionics (betaines). These agents can represent from 0.05 to 1%, preferably from 0.1 to 0.7%, more preferably 0.3 to 0.5% by weight relative to the weight of the ZnS of the suspension. The term “surfactant” is understood to mean a compound which modifies the surface tension of the suspension.

Said suspension can also include organic solvents, such as aliphatic and aromatic alcohols, glycol ethers (methanol, ethanol, propanol, isopropanol, propanediol, ethylene glycol, glycerol, benzyl alcohol, butoxy propoxy propanol, etc.). These solvents can represent from 0.1 to 50% of the weight of the suspension.

Mention may be made, as polymer matrix monomers, of caprolactam, in particular for the manufacture of polyamides, or ethylene glycol, especially for the manufacture of polyesters. These monomers can represent from 0.1 to 70% of the weight of the suspension, preferably from 15 to 60%. Preferably, the polymer matrix monomers are those used for the manufacture of the polymer matrix during the polymerization phase.

The suspension comprises, in addition to the ZnS, preferably water and optionally caprolactam and / or a surfactant, more preferably water and a surfactant. For the manufacture of polyamide 6, an aqueous suspension preferably comprising ZnS and optionally caprolactam, and optionally a surfactant, is used. For the manufacture of polyamide 66, an aqueous suspension preferably comprising ZnS and optionally a surfactant is used. For the manufacture of polyethylene terephthalate, use is preferably made of a suspension comprising ZnS in ethylene glycol and optionally a surfactant.

According to the invention, the ZnS can be in the form of particles comprising at least ZnS. Preferably, the ZnS is in the form of particles consisting essentially of ZnS crystals, optionally coated with at least one mineral and / or organic compound; in particular of the type of those used as pigment in thermoplastic polymer matrices; such as Sachtolith HD or HD-S products marketed by Sachtleben.

The ZnS particles may have an average diameter (d50) less than or equal to 5 μm, preferably less than or equal to 1 μm, more preferably from 0.1 to 0.5 μm, particularly an average diameter of approximately 0.3 to 0.5 μm.

The suspension can comprise from 5 to 40% by weight of ZnS, preferably from 10 to 30%, relative to the total weight of the suspension. The proportion by weight of ZnS relative to the total weight of the polymer composition can be from 0.01 to 10%, preferably from 0.1 to 7%, even more preferably from 0.2 to 5%, particularly from 0.3 at 3%.

Preferably, the suspension has a filterability greater than or equal to 2 L, preferably greater than or equal to 5 L, measured in particular by the quantity of suspension which can pass through a threshold filter 1 μm and 0.5 cm ² section before clogging; the suspension can be sucked through the filter using a vacuum pump. A filter provided by Gebr can be used for this purpose. Kufferath GmbH & Co (Dϋren) with the following references: Gewebe ISO 9044 (KT 400/2800 - Mw 0.315 Dr 0.20). Filterability is a parameter linked to the quality of the ZnS dispersion in the suspension.

By threshold filter is meant a filter which does not allow particles having a diameter greater than a value in μm to pass through. For example, a 1 μm threshold filter does not allow particles having a diameter greater than 1 μm to pass through. Said suspension can be manufactured by a process comprising at least the following steps: a) at least ZnS is brought into contact with water and / or at least one compound chosen from the group comprising: surfactants, organic solvents and or polymer matrix monomers; b) the mixture obtained in step a) is stirred in order to uniformly disperse the ZnS in water, in particular to reduce the size of the agglomerates; and c) the suspension obtained is filtered using a threshold filter of at least 10 μm, preferably at least 5 μm, more preferably at least 3 μm. It is in particular possible to dilute and / or allow the suspension to settle during the manufacturing process.

Preferably, the suspension is filtered several times in step c), in particular by passing it through several filters placed in series and using a recirculation loop. One can in particular place a 10 μm filter and a 5 μm filter in series and circulate the suspension in the loop for a few hours. It is also possible to place several circulation loops, identical or different, in series.

The presence of ZnS in a polymer matrix can be determined by various methods well known to those skilled in the art, such as a thermogravimetric analysis (ash method), or by direct qualitative analysis of the zinc and sulfur elements by X-ray fluorescence spectrometry. ; optionally followed by a quantitative elementary assay of the zinc element after sulfonitric mineralization by atomic spectrometry, so as to deduce the amount of ZnS therefrom. It is also possible to quantitatively determine the sulfur element by microanalysis and / or dissolving the polymer matrix in a solvent, filtering the additive and X-ray diffraction analysis. The present invention also relates to the use of the composition based on a thermoplastic matrix containing ZnS for the manufacture of articles, such as yarns, fibers and / or filaments, films and molded articles. The compositions can be shaped into articles directly after the polymerization, without intermediate solidification and recasting steps. They can also be shaped into granules, intended to undergo remelting for subsequent final shaping, for example for the manufacture of molded articles or for the manufacture of threads, fiber and / or filaments.

All the melt spinning methods can be used in particular by passing the composition of the invention through dies comprising one or more orifices. For the manufacture of multifilament yarns, mention is made of the spinning or spinning-drawing or spinning-stretching-texturing processes integrated or not, whatever the spinning speed. The yarns can be produced by high speed spinning, with a spinning speed greater than or equal to 300O m / min, preferably greater than or equal to 4000 m / min. Such processes are often designated by the following terms: POY (partialy oriented yarn), FOY (fully oriented yarn), FEI (spinning-stretching-integrated), HOY (higly oriented yarn with a speed greater than 5500 m / min). These threads can also be textured, depending on the use for which they are intended. The yarns obtained by these methods are particularly suitable for producing textile, woven or knitted surfaces. According to the invention, the thermoplastic polymer matrix can be used for the manufacture of multifilament yarns having a titer less than or equal to 6 dtex / filament, more preferably less than or equal to 1.5 dtex / filament. For the manufacture of fibers, the filaments can for example be combined in the form of a wick or sheet, directly after spinning or in recovery, drawn, textured or crimped and cut. The fibers obtained can be used for the manufacture of nonwovens or fiber yarns. The compositions can also be used for the manufacture of flock.

The yarns, fibers and / or filaments of the invention can undergo various treatments, such as for example stretching in a continuous step or in recovery, depositing sizing, oiling, interlacing, texturing, crimping, stretching, heat treatment for fixing or relaxation, grinding, twisting, and / or dyeing. For dyeing, mention is made in particular of the dyeing processes in bath or by jets. The preferred dyes are acid, metalliferous or non-metalliferous dyes.

The present invention also relates to an article obtained at least from yarns, fibers and / or filaments as defined above. These articles can be fabrics or textile surfaces, such as woven, knitted, non-woven or carpet surfaces. These items may be, for example, carpets, rugs, upholstery, upholstery, sofas, curtains, bedding, mattresses and pillows, clothing and medical textiles.

The present invention also relates to articles obtained by shaping a composition of the invention by a process chosen from the group comprising an extrusion process, such as the extrusion of sheets and films, molding, such as compression molding, and injection molding, such as injection molding.

Films can thus be obtained by the methods mentioned above using a flat die. Preferably, the thermoplastic matrix is composed of polyamide, polyester or polyolefin. The films obtained can undergo one or different stages of treatment, such as one-dimensional or two-dimensional stretching, a thermal stabilization treatment, an antistatic treatment or a sizing. The present invention also relates to a suspension containing ZnS. This suspension can in particular be used for the manufacture of articles based on a thermoplastic polymer matrix having anti-mite, antibacterial and / or anti-fungal properties.

According to the invention, the term "anti-mite, anti-bacterial and / or anti-fungal properties" means the action aimed at limiting, reducing or eliminating the mites, bacteria and / or fungi (mycetes) present in an environment.

By environment is meant any medium comprising at least mites, bacteria and / or fungi. The environment can be a solid, a liquid or a gas, preferably air. By reducing, we mean reducing the amount of mites, bacteria and / or fungi present in the environment, compared to the amount present in the environment before the introduction of polymeric matrix comprising ZnS. By reducing is also meant reducing the rate of growth and / or reproduction of said organisms over time and in the environment. The term “eliminate” is intended to eliminate the majority of said organisms from the environment, that is to say kill them or make them inactive.

Mites belong to the group of arthropods divided into subclasses: insects and arachnids. Dust mites are arachnids and are often parasitic and pathogenic. There are a multitude of known mites, several tens of thousands, a very limited number of which are harmful to humans. The mites have a size of 200 to 500 microns and are, practically, invisible to the eye. They mainly live in a humid atmosphere (65 to 80% relative humidity), obscure and at ideal average temperatures of 15 to 25 ° C. Their lifespan is around 3 months. Examples of mites that may be mentioned include, for example, the genera Acarus, Tyrophagus and others. The species Dermatophagoïdes is notably present in house dust and therefore relates more particularly to nuisances in humans. There are two varieties of Dermatophagoids, Dermatophagoids pteronyssinus and Dermatophagoids farinae.

The bacteria can be eubacteria or archaeobacteria. Eubacteria include fermicutes, gracilicutes and ternicutes. Gracilicutes include Gram negative bacteria such as Enterobacteriaceae, such as Klebsiellan such as Klebsiella pneumoniae and Escherichia, such as Escherichia coli. Fermicutes include Gram positive bacteria, such as Micrococcaceae, such as, for example, Staphylococci, such as Staphylococcus aureυs, and stems forming endospores including bacilli (Bacillaceae), such as, for example, Bacillus circulans. All these references are mentioned in Bergey's Manual of Systematic Bacteriology, Williams & Wilkens, 1st ed. Flight. 1-4, (1984).

Fungi are fungi. The term Myceteae includes Amastigomycota like for example Deuteromycotina which includes Deuteromycetes. The Deuteromycetes include Aspergillis, such as Aspergillus niger and Candida, such as Candida albicans.

A specific language is used in the description so as to facilitate understanding of the principle of the invention. It should nevertheless be understood that no limitation of the scope of the invention is envisaged by the use of this specific language. Modifications, improvements and improvements can in particular be envisaged by a person familiar with the technical field concerned on the basis of his own general knowledge. The term and / or includes the meanings and, or as well as all other possible combinations of the elements connected to this term.

Other details or advantages of the invention will appear more clearly in the light of the examples given below only for information.

Example 1: Preparation of ZnS suspension (slurry) The preparation of the ZnS suspension (Sachtolith HD-S from Sachtieben) at 20% was carried out as follows:

A premix (premix) is prepared by successively adding 240 kg of demineralized water, 10 kg of a 10% solution of Calgon PT (surfactant from the supplier Albright & Wilson) and 200 kg of ZnS in the form of a conducting powder. at 441 kg of suspension at 45.3%. The addition is made with stirring in a capacity equipped with a Kotthof brand high speed disperser. After the end of the addition, the suspension is kept stirring for 1 hour. The suspension is then diluted by adding 220 kg of demineralized water, then kept stirring for one hour. The 30.25% suspension is then transferred to a settling tank with a settling height of 30 cm, where it remains for 40 hours.

At the end of this settling, the concentration was measured in 2 ways: by gravimetry after evaporation of the water and by densimetry on the suspension: Gravimetry (2 measurements): 23.7% and 23.9%; and Densimetry: 1, 2165. The density value found is related to the concentration of ZnS (x) by the relation: suspension

Since pmo = 1 g / L and p _Zn s = 4 g / L, the concentration x is equal to 23.73% by this method.

The final dilution is made in a stirred reactor, adding 76 L of demineralized water to 330 L of suspension. The control of the final concentration by gravimetry provides 20.6%. The suspension thus obtained is filtered several times through a 5 μm threshold filter on a recirculation loop, so as to obtain a filterability of 4.0 L. The quality of the suspension is evaluated by measuring the filterability, ie the quantity of suspension which can pass through a threshold filter 1 μ and of 0.5 cm ² in section before clogging, the suspension being sucked through the filter using a vacuum pump. By comparison, a suspension of uncoated TiO ₂ (Hombitan LW-S type from Sachtieben), prepared under similar conditions, with a filterability value of 1.8 L.

EXAMPLE 2 PA 66 comprising ZnS introduced into the polymerization A polyamide 66-based copolymer is produced from 2,634 kg of an aqueous solution of a 52% hexamethylene diammonium adipate salt (N salt) by weight and to which are added: 2200 crn ³ of an aqueous solution at 5.8% of manganese acetate tetrahydrate (Riedel origin of Hahn); 50 g of a 25% antifoam emulsion (STE from Wacker Chemie); 42.3 kg of a 75% aqueous solution of caprolactam; - 794 g of a 70% aqueous solution of acetic acid; and

The polyamide is produced according to the standard process comprising a step of concentrating the solution in the evaporator and a polycondensation step in an unstirred autoclave reactor, which comprises the following phases: a phase of approximately 86 min of distillation under pressure, under a pressure bearing of 18.5 bars for which the final temperature is 253 ° C, a decompression phase of approximately 72 min from 18.5 bars to 1 bar with a final temperature of 269 ° C a finishing phase of approximately 22 min for which the final temperature is 278 ° C. - an extrusion phase of approximately 15 min under a nitrogen pressure of 3.8 bar.

During the distillation phase under pressure after 39 min, the 125 kg of the aqueous suspension of ZnS (in a few minutes) prepared in Example 1 are added. A copolymer based on PA66 comprising 2.5% by weight is obtained of polyamide 6 motifs.

The polymer obtained is analyzed by the usual methods and its characteristics are: Relative viscosity = 40.9 (at 8.4% in formic acid 90% at 25 ° C) Amine end groups = 51, 1 meq / kg - Groups carboxyl terminals = 80.6 meq / kg ZnS = 2.05% (measured by the ash rate, correcting the result to take account of the combustion of ZnS to ZnO)

Example 3: Spinning of PA 66 with ZnS The polyamide obtained in Example 2 is remelted in a single screw extruder and extruded at 290 ° C through a die having 68 holes. The wire obtained is returned at a speed of 4200 rn / min. The characteristics of this wire are collated in table 1. The pressure on the spinning pack is 220 bar, and does not increase (<1 bar / day).

Comparative Example 4: Spinning of PA 66 with addition of ZnS via masterbatch A semi-mat PA 66 polyamide containing 0.3% of TiO ₂ (Hombitan LW-S type from Sachtieben) produced by a process similar to that described in Example 2 is spun under the same conditions as in Comparative Example 3, but with the addition of a ZnS masterbatch at the input of the extruder. This masterbatch contains 40% ZnS (Sachtolith HD-S type) and 60% polyamide 6 and is produced by Sachtieben (under the name PA-ZS 40 X18 white).

The pressure on the spinning pack is initially 220 bar and increases rapidly (approximately 20O bar / day), which makes this route impossible to industrialize.

Example 5 Comparison of Antibacterial PA 66 Yarn (Without ZnS) and of

PA66 comprising ZnS introduced for polymerization

A polyamide PA 66 large mat containing 1.7% TiO ₂ (Hombitan LW-S type from Sachtieben) produced by a process similar to that described in Example 2 is spun under the same conditions as in Example 3, but with the addition of a masterbatch at the entrance of the extruder. This masterbatch contains

20% of a mineral additive containing 3.7% silver ions and 80% polyamide 6.

The characteristics of the wires are collated in Table 1:

Table 1

The dynamic measurements are carried out on a Calderra-Bossi TCT dynanometer (distance between the jaws of 250 mm, Return speed: 250 mm / min., Applied prestressing force of 2.6 cN).

The Uster coefficient (%) is representative of the regularity of a thread. It is determined by measuring the variations in the titer of a continuous wire on a Uster device

(Zellweger).

An Elkometer can detect wire faults, such as broken strands and curls.

Knitwear (sock type) are knitted from POY 98f68 threads. The degree of yellow is determined using an “Elrepho” spectrophotometer (supplier: Zeiss) using a white standard B aSO ₄ DIN 5033. The degree of yellow is measured from the RX remission components. (red component) and RZ (blue component). The degree of yellow is equal to RX minus RZ. The heat setting is carried out after the knitted fabrics have been passed through a heat setting branching machine at 190 ° C. for 45 seconds.

Thus, it appears that the wire of Example 3 has characteristics similar to that of Comparative Example 5, but with a much whiter appearance, thus avoiding the main defect of the antibacterial silver wires. The pressure on the pack is 220 bar and does not increase (<1 bar / day). Example 6: Texturing of the Yarns of Example 5 The POY yarn obtained in Example 3 is textured with a drawing ratio of 1.22, a D / Y of 1.86, an oven temperature of 210 ° C. and an aggregate of discs of type 1-6-1, leading to a tension of 17 g before and 18 g after the aggregate. The POY yarn obtained in Comparative Example 5 is textured. The characteristics of the textured yarns obtained are summarized in Table 2:

Table 2

Thus, it appears that the wire of Example 6 has similar or better characteristics compared to that of Comparative Example 6.

Example 7: Antibacterial activity The antibacterial activity is measured according to standard JIS L 1902: 1998 on the bacteria Staphylococcus aureus ATCC 6538P for:

the yarns of Example 3 obtained by adding ZnS in polymerization, and

- the threads of comparative example 4 obtained by adding ZnS via masterbatch. Said activity is also compared to wires not comprising ZnS. The tests are carried out on 18 mm by 18 mm knitted surfaces.

The different surface areas of the samples are brought into contact with the same number of bacteria, for incubation at 37 ° C. for 18 hours. At time t = 0 and t = 18h, the number of bacteria is counted.

After verifying the good growth of the bacteria in the control samples, the average number of active bacteria immediately after inoculation on the different samples is determined for each sample. average number of active bacteria after 18 hours of incubation on the different samples, in cfu (colony forming unit / unit forming a colony). We then measure the specific bacteriostatic activity S corresponding to the difference between the logarithm of the average number of active bacteria after 18 hours of incubation on the control sample (without ZnS) and the logarithm of the average number of active bacteria after 18 hours d incubation on the sample (with ZnS). The results are expressed in Table 3:

Table 3

A higher antibacterial activity is thus observed with the threads according to the invention, in which the ZnS was introduced during the polymerization process, compared with the threads in which the ZnS was introduced by mixing with the polyamide matrix.

Claims

1. A method of manufacturing a composition based on a thermoplastic polymer matrix containing ZnS, characterized in that a suspension containing ZnS is introduced before or during the polymerization of said polymer matrix.

2. Method according to claim 1, characterized in that the thermoplastic polymer matrix is chosen from the group comprising: polyamides; polyesters; polyvinyls; polyvinyl chlorides; polyvinyl acetates; polyvinyl alcohols; acrylic polymers such as PMMA, SAN, ABS copolymers; polyolefins such as polyethylene, polypropylene and polybutylene; cellulose derivatives such as acetate cellulose, cellulose-ester plastics, polyurethanes, their copolymers and / or mixtures.

3. Method according to claim 1 or 2, characterized in that the thermoplastic polymer matrix is chosen from the group comprising: polyamide 6, polyamide 6.6, polyamide 11, polyamide 12, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), their copolymers and / or their mixtures.

4. Method according to claim 3 or 4, characterized in that the polyamide 66 polymerization process comprises a step of concentration of salt N and a polycondensation step comprising the following phases: a pressure distillation phase, a decompression phase , a finishing phase and possibly an extrusion or shaping phase; said suspension being added during the distillation phase.

5. Method according to claim 3 or 4, characterized in that the polyamide 6 polymerization process comprises a step of mixing molten caprolactam with water and optionally chain limiters, a step of heating, possibly a step of increasing the pressure followed by a step of decompression, optionally a step of finishing under vacuum, a step of extraction, and a step of drying; said suspension being added at the initial stage of mixing the molten caprolactam with water and optionally chain limiters.

6. Method according to claim 3 or 4, characterized in that the polyester polymerization process comprises a mixing step, a transesterification or esterification step, optionally a concentration step, and a polycondensation step under vacuum; said suspension being added before or just before the polycondensation phase.

7. Method according to any one of claims 1 to 6, characterized in that said suspension comprises, in addition to the ZnS, water and / or at least one compound chosen from the group comprising: surfactants, organic solvents and / or polymer matrix monomers.

8. Method according to any one of claims 1 to 7, characterized in that said suspension comprises water and optionally caprolactam and / or a surfactant.

9. Method according to any one of claims 1 to 8, characterized in that said suspension comprises at least, in addition to ZnS, water and a surfactant.

10. Method according to claim 8 or 9, characterized in that the suspension comprises from 0.05 to 1%, preferably from 0.1 to 0.7%, more preferably 0.3 to 0.5% by weight. relative to the weight of the ZnS of the suspension.

11. Method according to any one of claims 1 to 10, characterized in that said suspension comprises ethylene glycol.

12. Method according to any one of claims 1 to 11, characterized in that the ZnS is in the form of particles consisting essentially of ZnS crystals, optionally coated with at least one mineral and / or organic compound.

13. The method of claim 12, characterized in that the particles have an average diameter (d50) less than or equal to 5 microns.

14. Method according to any one of claims 1 to 13>, characterized in that the suspension comprises from 5 to 40% by weight of ZnS, preferably of

10 to 30%, based on the total weight of the suspension.

15. Method according to any one of claims 1 to 14, characterized in that the composition based on a thermoplastic polymer matrix comprises from 0.01 to 10% by weight of ZnS.

16. Method according to any one of claims 1 to 15, characterized in that said suspension has a filterability greater than or equal to 2 L, preferably greater than or equal to 5 L; measured by the amount of suspension which can pass through a threshold filter 1 μm and 0.5 cm ² in section before it becomes clogged, said suspension being able to be sucked through the filter using a vacuum pump.

17. Composition based on a thermoplastic polymer matrix containing ZnS capable of being obtained by the process according to any one of claims 1 to 16.

18. A method of manufacturing a suspension containing ZnS comprising at least the following steps: a) at least ZnS is brought into contact with water and / or at least one compound chosen from the group comprising: surfactants -actives, organic solvents and / or monomers of polymeric matrix; b) the mixture obtained in step a) is stirred in order to homogeneously disperse the ZnS in water; and c) the suspension obtained is filtered using a threshold filter of at least 10 μm, preferably at least 5 μm, more preferably at least 3 μm.

19. Suspension containing ZnS capable of being obtained by the process of claim 18.

20. Use of the composition based on a thermoplastic matrix containing ZnS obtained by the manufacturing process according to any one of claims 1 to 16 for the manufacture of articles, such as fiber and / or filament yarns, films and articles molded.

21. Use according to claim 20 for the manufacture of multifilament yarns having a titer less than or equal to 6 dtex / filament, preferably less than or equal to 1.5 dtex / filament.

22. Use of a suspension containing ZnS for the manufacture of articles based on a thermoplastic polymer matrix having anti-mite, anti-bacterial and / or anti-fungal properties.