EP1896529A1

EP1896529A1 - Method for antimicrobial finishing of polymers

Info

Publication number: EP1896529A1
Application number: EP06754480A
Authority: EP
Inventors: Norbert Schall; Thomas Engelhardt; Klaus Heinemann; Nicole Klose; Wolfgang Müller
Original assignee: Sued Chemie AG
Current assignee: Sued Chemie AG
Priority date: 2005-06-21
Filing date: 2006-06-21
Publication date: 2008-03-12
Also published as: WO2006136397A1

Abstract

The invention relates to a method for antimicrobial finishing of a polymer, in which (a) an organophilic sheet silicate which contains antimicrobially effective onium ions is produced, wherein a starting sheet silicate is loaded with onium ions preferably to a measure beyond the cation exchange capacity of the starting sheet silicate, (b) the organophilic sheet silicate is mixed with the polymer and (c) the polymer is preferably not provided with antimicrobial effective metals or metal compounds. An antimicrobial plastic additive and an antimicrobial polymer composition are also disclosed.

Description

METHOD FOR THE ANTIMICROBIAL EQUIPMENT OF POLYMERS

The present invention relates to a process by which polymers, especially thermoplastic polymers, are antimicrobially finished using layered silicates, i. a process for the preparation of polymers or polymer compositions with antimicrobial properties.

The antimicrobial finish of polymers is important for various technical fields. Originally, technical textiles produced from polymers were provided with antimicrobial properties in order to avoid, for example, infestation with mold fungi. In addition to technical textiles, other textiles made of polymeric materials are increasingly being equipped with antimicrobial properties. Especially in the healthcare sector, antimicrobial properties are desired, for example, for workwear, textile equipment and consumer textiles (eg bed linen, towels) as well as for medical products (eg surgical suture material). Also with personal care and hygiene products (eg toothbrushes) an antimicrobial effect can be advantageous. In the food industry, for example, antimicrobially treated polymeric packaging agents are of interest. In addition, sports and leisure time clothing increasingly provided with antimicrobial functionality.

The prior art discloses various possibilities of antimicrobial finishing of polymers, in particular of textiles. A common practice was and is the application of active ingredients to the textile structure. In the further development, the aim was to chemically fix the sometimes toxic substances on the fiber surface. Chlorinated phenols have been used, such as pentachlorophenol and trichlorophenol, but because of their toxicity play no role, salicylanilide and its derivatives.

With the use of textiles finished in this way, however, a potential health impairment is associated, since the superficially applied or fixed antimicrobial substances are absorbed by the skin during contact and, if appropriate together with ingredients of cosmetics and cleaning agents, can lead to skin irritations and allergies. In addition, the antimicrobial activity of polymers provided with surface-applied or fixed antimicrobial substances generally decreases with the duration of use, e.g. by washing the finished textiles the applied antimicrobial substances are removed.

In order to reduce the risk of health risks and to achieve permanent antimicrobial efficacy, non-diffusing or non-leachable substances, such as metals and metal compounds, were used. For example, DE 199 56 398 A1 describes an antibacterially active polymer-based synthetic fiber which contains silver or a silver compound. US 6,037,057 discloses an antimicrobial polyester fiber, which contains silver, silver oxide, silver halides, copper, copper (I) oxide, copper (II) oxide, copper sulfide, zinc oxide, zinc sulfide and / or zinc silicate. JP 2002155424 is directed to a polyester fiber containing inter alia a silver-based inorganic antimicrobial agent. JP 10292107 A2 describes an antimicrobial polyamide containing copper. JP 10085590 A2 is directed to a filter for water purification. The filter consists of two layers, one layer containing a metal ion-containing zeolite and a binder. The metal used is silver, copper, zinc and / or cobalt. The binders mentioned are clays, synthetic resins and fibers. Examples of clays are kaolin and bentonite. Examples of synthetic resins are polyesters, polyamides, cellulose, polyethylene, polypropylene, acrylic resins and acrylonitrile-butadiene-styrene copolymers.

On the one hand, the disadvantage of using silver and other metals is that the metal has to be brought into a very fine distribution by technical / technological measures in order to have antimicrobial activity and, on the other hand, a necessary silver, copper or other doping places a burden on the economy of the respective procedure. In addition, a more or less strong discoloration of the polymer, depending on the metal used and the degree of doping, unavoidable.

JP 2004018661 A2 describes antimicrobial active moldings of thermoplastic polymers which contain hinokitiol (2-hydroxy-4-isopropyl-2,4,6-cycloheptatriene-1-one). The hinokitiol is present in the intermediate layers of a clay mineral with a layer structure. For example, a film is made from a composition containing polyethylene and the hinokitiol-clay composite. The hinokitiol-clay composite is made by mixing of montmorillonite with tetramethylammonium chloride and adsorption of hinokitiol. The antimicrobial effectiveness of the polymer molding is based on the use of Hinokitiols. A clay mineral containing no hinokitiol but only tetramethylammonium chloride is not antimicrobially active. Furthermore, during compounding in thermoplastics, there is no exfoliation of the phyllosilicates, which limits the microbiological effectiveness. In addition, a deterioration of the mechanical properties can be observed.

According to DE 101 16 751 Al, antimicrobially finished polymers, especially bioactive fiber products, are produced from a polyester which has condensed phosphorus-containing chain links. A disadvantage of these fiber products is that the content of phosphorus is reduced under hydrolysis conditions during the aftertreatment of the textiles produced from the fiber products. This reduction is due to the presence of hydrolysis-sensitive phosphoric acid ester groups. In addition, due to the position of the P-O bond in the main chain of the polyester, the hydrolysis is also associated with a decrease in molecular weight. As a result of the hydrolysis reactions, measurable changes in the textile-physical properties of the polymer may result, e.g. a reduction in the tensile strength of the filaments (see M. Sato et al., J. of Appl., Polym., Sc., 78 (2000) 1134-1138).

Clay minerals containing antimicrobial onium ions are described in J. of Materials. 29 (1994) 11-14. However, there is no indication that these clay minerals can be incorporated into polymers while retaining and even advantageously providing the antimicrobial activity. EP 0 846 660 A2 also discloses that onium ions can be intercalated into phyllosilicates and describes the mixing of exfoliated phyllosilicates with polymers. However, this document also does not indicate that phyllosilicates containing antimicrobial onium ions can be used to antimicrobialize polymers.

Starting from the methods for the antimicrobial finishing of polymers known in the prior art, the object, according to a first aspect, to provide a method which avoids the disadvantages of the prior art and in particular provides an improved antimicrobial activity. According to one aspect of the invention, the following requirements are met in particular: The antimicrobially active component is introduced into the polymer in a form which ensures that the antimicrobial activity is retained during use of the polymer and the risk of health impairments (eg skin irritation and skin irritation) Allergies) is minimized. In particular, the antimicrobial finish obtained by the process is also maintained under hydrolysis conditions. The process results in a technically simple and cost-effective manner to an antimicrobial polymer.

The above requirements are met according to a first aspect of the invention by a process for the antimicrobial finishing of a polymer or for the production of a polymer composition with antimicrobial properties, in which an organophilic phyllosilicate containing antimicrobial onium ions is produced, wherein a starting point layered silicate is loaded with onium ions, preferably to an extent in excess of the cation exchange capacity of the starting layer silicate; the resulting organophilic layered silicate is mixed with the polymer, and preferably the polymer is not finished with antimicrobial metals or metal compounds.

In particular, according to the invention, preferably no silver and no silver-containing compounds are used.

By "antimicrobial equipment" is meant an antimicrobial, e.g. an antibacterial, fungicidal, virostatic and / or a-caricoid activity or property understood. All substances from the literature that have antimicrobial activity are recorded. In principle, any tests which are familiar to the person skilled in the art for the detection of the antimicrobial activity can be used; Specific tests are mentioned below.

Antimicrobially active metals and metal compounds include e.g. Silver, copper, zinc, cobalt and their compounds, e.g. Silver oxide, silver halides, copper oxides, copper sulfide, zinc oxide, zinc sulfide and zinc silicates.

According to a preferred embodiment of the invention, no hinokitiol (see above) is used.

The polymer is preferably a thermoplastic polymer, for example a polyolefin (for example polyethylene and polypropylene), a polystyrene, a vinyl polymer (for example polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate and polyvinyl alcohol), a polyester ter (for example, polyethylene terephthalate), a polyamide, a polyacrylonitrile, a copolymer of said polymers or a mixture of said polymers and / or copolymers.

Preferably, the thermoplastic polymer is a polyester or a polyamide.

The organophilic layered silicate containing antimicrobial onium ions is prepared by subjecting a starting layer silicate to cation exchange with onium ions, including antimicrobial onium ions.

In one aspect of the invention, it has been found that particularly advantageous products with improved antimicrobial properties are obtained when the starting layer silicate is loaded with (antimicrobially active) onium ions to an extent beyond the Cation Exchange Capacity (CEC) of the starting layer silicate goes. The determination of the cation exchange capacity of the starting layer silicate is preferably carried out by the ammonium chloride method. For this purpose, 5 g of phyllosilicate are sieved through a 63 μm sieve and dried at 110 ^° C. Then exactly 2 g are weighed into an Erlenmeyer flask and mixed with 100 ml of 2N NH ₄ C1 solution. The suspension is boiled under reflux for 1 hour. After a service life of 16 hours at room temperature, the NH _4- exchanged phyllosilicate is filtered off via a membrane filter and washed with demineralized water (about 800 ml) until extensive freedom from ions. The washed out NH ₄ - layer silicate is removed from the filter, dried at HO ⁰ C for 2 hours, ground, sieved and dried again at 110 ⁰ C for 2 hours. Thereafter, the NH ₄ - of the layered silicate to Kjeldahl. The CEC of the layered silicate can be calculated according to the following formula: CEC (mVal / 100 g) = above the fraction X times 1000 by 14.0067; X = nitrogen content of NH _4- exchanged layered silicate in percent by weight.

The loading level of the layered silicate exchanged with onium ions can be determined by carbon analysis with a Vario EL 3 carbon analyzer from Elementa according to the manufacturer's instructions, the carbon content being converted into the amount of onium ions and compared with the CEC.

It has surprisingly been found that in such a treatment or occupancy of the layered silicate with one or more onium compounds over the cation exchange capacity of the layered silicate addition particularly advantageous antimicrobial efficiencies can be achieved. In particular, improved long-term efficacy was demonstrated compared to the use of layered silicates not treated beyond the cation exchange capacity of the layered silicate.

According to a further aspect, in the method according to the invention, the amount of onium ions used for the treatment of the starting layer silicate can also be calculated via the respective molecular weight such that it is computationally sufficient to overcoverage the layered silicate beyond its cation exchange capacity.

Particularly preferably, the coating of the layered silicate with the onium ions is at least about 105%, in particular at least about 110%, preferably at least about 120%, based on the CEC of the layered silicate. A preferred range is between more from 100% to about 250% of the CEC, in particular from greater than 100% to about 200% of the CEC of the layered silicate.

As starting layer silicate natural or synthetic phyllosilicates can be used. Natural or synthetic swellable phyllosilicates are preferably used. Examples of preferred phyllosilicates are Montmorillonite, Hectorite, Illite, Vermiculite, Beidellite, Nontronite, Volkonskoite, Saukonite and Saponite. For example, Na ⁺ , Ca ²⁺ , K ⁺ , Mg ²⁺ and / or NH ₄ ⁺ ions are present in the intermediate layers of the starting layer silicates. The starting layer silicates can be used singly or as a mixture of several different starting layer silicates. More preferably, natural sodium montmorillonite is used as the starting layer silicate.

The starting layer silicates can be cleaned before use. In this case, according to a preferred embodiment, the starting layer silicate is slurried in water, optionally filtered, and then, for example. wet-cleaned by means of cyclones or centrifuges. For example, a powdered natural sodium bentonite (Volclay Dust from Volclay International) is dispersed with water for 30 minutes in a water with a Pentraulikrührer so that results in a 6% suspension. The suspension is then diluted to 3% with water and passed through a 0.063 mm sieve. The passed suspension is then pumped through a cyclone at a pressure of 2 bar and thus purified at a rate of 2 liters per minute.

The cation exchange can be carried out using one or more (antimicrobially active) quaternary onium compounds. It is also possible to use mixtures of antimicrobially active and non-antimicrobially active quaternary onium Connections are used. The antimicrobial activity of the onium ions used can be determined as known to the person skilled in the art from the literature, see, for example, H. Hamada et al., J. Antibact. Anti Fung. Agents 17 (1989), 319 or Y. Nakagawa, i-bid. 17 (1989), 333.

The quaternary ammonium compounds may e.g. Be compounds having the following formula:

[R ₁ R ₂ R ₃ R ₄ N ⁺ ] X ^"

wherein Ri, R ₂ and R ₃ independently represent an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 12 carbon atoms or an aralkyl group having 6 to 12 carbon atoms, R _{4 represents} an alkyl group having 10 to 18 carbon atoms - represents atoms and X ^"is a fluoride, chloride, bromide or iodide.

Examples of preferred ammonium compounds are compounds in which R ₁ , R ₂ and R ₃ independently represent an alkyl group of 1 to 6 carbon atoms, R _{4 represents} an alkyl group of 8 to 18 carbon atoms and X ^'is a chloride or bromide ; Compounds in which R ₁ and R ₂ independently represent an alkyl group having 1 to 6 carbon atoms, R ₃ and R ₄ independently represent an alkyl group having 10 to 18 carbon atoms and X ^"is a chloride or bromide, and compounds wherein Ri and R ₂ independently represent an alkyl group of 1 to 6 carbon atoms, R _{3 represents} an aryl or aralkyl group of 6 to 12 carbons, R _{4 represents} an alkyl group of 10 to 18 carbon atoms, and X ^" Chloride or bromide. Particularly preferred antimicrobially active quaternary ammonium compounds are benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, benzyldimethyloctadecylammonium chloride, didecyldimethylammonium chloride, dioctadecyldimethylammonium chloride and hexadecyltrimethylammonium chloride.

As a source of antimicrobial onium ions, pyridinium compounds can also be used in the cation exchange process. Examples of antimicrobial pyridinium compounds are compounds of the formula

[C ₅ H ₅ N ⁺ -R ₅ ] X ^"

in which R _{5 represents} an alkyl group with 10 to 18 carbon atoms and X ^"is a fluoride, chloride, bromide or iodide .Pyridinium compounds which are preferably used are, for example, dodecylpyridinium chloride, dodecylpyridinium bromide, hexadecylpyridinium chloride and hexadecylpyridinium bromide Further examples of antimicrobial agents which can be used Pyridinium compounds are acriflavinium chloride (3, 6-diamino-10-methyl-acridinium chloride) and dequalinium chloride [1,1'-decamethylenebis (4-amino-quinaldinium) dichloride].

Furthermore, the cation exchange can be carried out using antimicrobially active quaternized guanidine derivatives, for example quaternized chlorhexidine. Quaternized sulfonamide derivatives, for example quaternized sulfanilamide, quaternized 4- (aminomethyl) benzenesulfonamide, quaternized sulfothiazole and quaternized 2- (4-thiazolyl) benzimidazole are also suitable as antimicrobial onium compounds. The quaternization of the guanidine derivatives and the sulfonamide derivatives can be carried out in a known manner, for example with dimethyl sulfate, benzyl chloride, Ethyl or methyl 4-toluenesulfonate take place (see eg Organikum, 20th edition, 1999, Verlag Wiley-VCH, page 236). Phosphonium compounds are also detected.

Preferably, onium ions having two or more positive charges (two or more quaternary onium groups) in one molecule are not used. These have turned out to be less advantageous. This could be due to the fact that (without the invention being limited to this assumption), the bridging of the sheet silicate platelets is prevented, which prevents advantageous exfoliation in the polymer.

For cation exchange only onium compounds of the same kind can be used or a mixture of different onium compounds can be used.

The cation exchange is preferably carried out as follows:

In a first step, the starting layer silicate is suspended in a solvent, preferably water, and swollen. The suspending and swelling of the starting layer silicate is preferably carried out with stirring and at a temperature of 20 to 90 ⁰ C over a period of 0.5 to 3 hours.

In a further step, one or more onium compounds, preferably in the form of an aqueous solution, are mixed with the suspension of the starting layer silicate. The mixing of the Ausgangsschichtsilicats with the onium compound or onium compounds can be carried out between 40 and 80 ⁰ C, in a preferred embodiment also with stirring and at a temperature of 20 to 90. ⁰ C, preferably. It is preferred after mixing the starting layer silicate with the onium compound (s). Bindung (s) the resulting mixture or suspension for a further 0.5 to 3 hours at 40 to 90 ⁰ C stirred.

Subsequently, the resulting organophilic layered silicate is separated, for example by filtration. In one embodiment, in the cation exchange, the amount of water used can also be minimized by extruding the layered silicate and the onium compound (s) with little or no water added. The organophilic layered silicate is preferably dried so that the residual moisture content is not more than about 0.8% (determined by drying at 110 ^° C.). The drying can be carried out for example at 80 to 90 ⁰ C in a convection oven and / or vacuum oven.

The organophilic layered silicate is preferably ground (eg in a centrifugal mill) and classified (eg by sieving), so that a particle size (D ₉₀ ) of less than 40 μm is obtained. Preferably, the Di ₀₀ is less than 40 microns. The smallest possible grain size can contribute to a uniform distribution of the organophilic layer silicate in the polymer. Furthermore, it has surprisingly been found that the use of a (dried) organophilic layered silicate having the above particle size favors the effect of an additionally applied nonionic antimicrobial substance (see below). As a result of the cation exchange, the layered silicate undergoes a layer widening, for example from 10 Å to about 19 Å, and this can reach values of up to about 48 Å, depending on the space requirements of the intercalated and / or adsorptively bound molecules.

As stated above, according to a particularly advantageous embodiment of the invention, the organophilic layer silicate containing the antimicrobial onium ions, wherein the starting layer silicate is loaded with onium ions to an extent in excess of the cation exchange capacity of the starting layer silicate. This can be done in one or more steps.

For example, such loading can be achieved by moistening the organophilic layered silicate prepared as described above in a further step with water and adding one or more onium compounds. The onium compounds mentioned may be the same compound or compounds used to prepare the organophilic layered silicate. Alternatively, an onium compound or a mixture of onium compounds which has not already been used in the preparation of the organophilic layered silicate can be used. The onium compound or the mixture of several onium compounds is preferably used in the form of an aqueous solution. The organophilic phyllosilicate moistened with water and mixed with the onium compound (s) is well mixed, eg in a Werner & Pfleiderer Z-kneader at room temperature for 30 minutes at medium speed. Subsequently, the material for example 80 is milled to 90 ⁰ C in a convection oven and / or vacuum drying oven and, if necessary, and classified (see above).

According to one aspect of the invention, it has been found that the portion of the onium ions which exceeds the cation exchange capacity of the layered silicate plays a role for a particularly good antimicrobial effectiveness, in particular a long-term effectiveness. It is therefore possible according to an invention that in a first step the cation exchange capacity of the Partially or partially by conventional (and possibly particularly inexpensive) non-antimicrobial effective O- nium- ions is occupied, and in a subsequent step further treatment with antimicrobial onium ions takes place. Preferably, however, at least one antimicrobially active quaternary onium compound is used both in the first and in the second treatment step. It has surprisingly been found that occupying the starting layer silicate in two (or more) sequential steps can provide better antimicrobial long-term efficacy of the products in one step compared to treatment with onium ions. Such treatment of the layered silicate in two or more steps, preferably with different antimicrobial onium ions, is therefore preferred.

According to a preferred embodiment of the invention, the already treated in a first step with at least one onium compound or occupied organophilic layered silicate is additionally treated with at least one further antimicrobial substance. This is preferably selected from antimicrobial onium ions (as described herein) and / or at least one non-ionic antimicrobial substance.

Thus, according to one aspect of the present invention, it has been found that the antimicrobial activity of the organophilic layer silicates described above can still be surprisingly improved if they are treated with at least one additional nonionic antimicrobial substance. The organophilic phyllosilicate and the non-ionic antimicrobial substance apparently act synergistically together. According to a particularly preferred embodiment, therefore, the organo philated sheet silicates additionally loaded with at least one anti-microbially effective non-ionic, in particular non-cationic (cationic), substance. This loading is, as stated above, more preferably beyond the CEC of the layered silicate addition.

The incorporation of the further antimicrobially active substance (s), in particular the non-ionic antimicrobial substance (s) takes place according to a preferred embodiment in a 2-stage process. According to a preferred aspect of the invention, therefore, the starting layer silicate already coated with onium ions in a first step is treated in a second step with the further antimicrobially active substance. In this case, the antimicrobial substance used in the second stage particularly preferably has a higher antimicrobial activity than the onium compound used in the first stage, in particular based on equal molar amounts. In this case, the starting layer silicate is preferably initially coated with the onium ions, dried and optionally ground, as described above. Then, in a further process step, the organophilic phyllosilicate thus obtained is kneaded or intensively mixed with the nonionic antimicrobial substance, in particular in the form of a solution in an organic solvent. For this purpose, for example, first a natural sodium bentonite is dispersed in water and the non-swellable secondary constituents are separated off by a wet cleaning process. Subsequently, the cation-active Interkalationskomponente (onium ions) is metered in as an aqueous solution with vigorous stirring. The resulting precipitate is separated, filtered, washed and dried. Subsequently, the dried precipitate with a suitable mill to a particle size D ₁₀ o <40 microns milled. The dried and dried Grinded organophilized bentonite is then preferably placed in a Z-kneader or high-speed heating-cooling mixer and then intensively mixed with vigorous stirring or mixing with the dissolved in a suitable organic solvent non-ionic antimicrobial substance. The mixing or kneading process can be carried out both at room temperature and elevated temperature. Experience has shown that mixing or kneading times between 2 and 40 minutes are sufficient. After completion of the kneading or mixing process, the product usually obtained as moist granules is dried, then ground with a suitable mill and classified to a particle size Di ₀₀ <40 microns. In this form, the product can then be incorporated into the polymer.

In particular, isothiazolines, isothiazolones such as octhilinone (2-octyl-3 (2H) -isothiazolone) or 4,5-dichloro-2-octyl-3 (2H) -isothiazolin-3-one are preferred non-ionic, antimicrobially active substances (DCOIT), carbamate derivatives such as 3-iodo-2-propynyl-N-butylcarbamate, halogenated sulfonamides such as chloramine T (N-chloro-4-toluenesulfonamide - Na-SaIz), halo-containing phenol derivatives such as tebuconazole (1- (4-chloro -phenyl) -4,4-dimethyl-3- (IH-1,2,4-triazol-1-ylmethyl) -3-pentanol), tricarboicarban (N- (4-chlorophenyl-N "(3, 4 dichlorophenyl) urea) or triclosan (5-chloro-2- (2,4-dichlorophenoxy) -phenol) For the sake of simplicity, the term "organophilic layered silicate" is also used hereinafter for those which have more than one an onium compound (in one or more steps) and optionally additionally with further antimicrobially active substances, in particular with at least one nonionic antimicrobial substance behan delt are. The mixing of the polymer with the organophilic (loaded) layered silicate (incorporation) is preferably carried out in a manner which results in at least partial exfoliation of the organophilic layered silicate. Exfoliated phyllosilicates are characterized in that the layers (platelets) which are originally connected to one another in the phyllosilicate are present in a matrix, for example a polymer, separated from one another and present in highly isolated form. Exfoliation can be achieved, for example, by heating the organophilic layered silicate, subjecting it to mechanical stress (eg in an extruder, stirrer, Banbury mixer, Brabender mixer or in an injection molding apparatus), sonication or pressure fluctuations. An exfoliation by mechanical stress is achieved, for example, at shear rates in the range of 10 s ^"1 to 20,000 s ^{" 1} . The exfoliation can be checked by WAXS examination as indicated before the examples. The exfoliation of the organophilic layered silicates is clearly evident from the fact that it is no longer possible to determine layer distances which can be measured by X-ray analysis in the case of non-exfoliated, organophilic layered silicates, even when mixed with the corresponding polymers.

In a preferred process, the polymer and the organophilic layered silicate are extruded together. Exfoliation of the layered silicate can be achieved in the extruder, for example under the following conditions: use of a co-rotating twin-screw extruder with 25 mm screw diameter, L / D ratio> 20, speed of the screw 100th to 500 rpm, preferably 300 rpm, throughput of the polymer layered silicate Mixture <10 kg / h, preferably <5 kg / h. The temperature during mixing depends on the polymer used. Thus, for example, incorporation of the layered silicate in polyamide 6 at 230 to 26O ⁰ C take place. The speed of the screws is in this case preferably 200 to 400 rpm, resulting in a throughput of about 3 - 6 kg / h. When using polyethylene terephthalate can be carried out at a temperature of 260 to 280 ⁰ C, the speed of the screw can also be 200 to 400 rpm, resulting in a throughput of 3-6 kg / h.

In another preferred method, the organophilic layered silicate may be added to the monomers from which the polymer is made prior to or during polymer synthesis to obtain a polymer in which the organophilic layered silicate is in exfoliated form. During polymer synthesis, e.g. the polymerization temperature and / or mechanical stress of the layered silicate are adjusted so that exfoliation of the layered silicate occurs (e.g., by agitation of the polymerization batch to give a shear rate in the above range).

According to one embodiment of the invention, for example, in the case of the antimicrobial finish of polyamide 6 prior to the start of the polymerization, the organophilic layered silicate can be added to the molten monomer (caprolactam) in a stirred autoclave with intensive stirring at 250 rpm, the caprolactam already intercalating the layered silicate and Subsequently, during the polymerization at 220 to 250 ⁰ C with further stirring at 250 rpm exfoliation begins.

Also in the polycondensation of polyethylene terephthalate, the organophilic layered silicate the polycondensation approach in a stirred autoclave with stirring at about 250 rpm are added. Alternatively, the organophilic layered silicate can be added to the reaction mixture at the time that about 40% by weight of the theoretically expected ethylene glycol is distilled off. By doing so, the thermal stress of the layered silicate can be reduced.

The organophilic layered silicate is added to the polymer preferably in an amount of from 0.01 to 5.00% by weight, more preferably in an amount of from 0.05 to 3.00% by weight, based on the polymer. The organophilic layered silicate can be added to the polymer in pure form in the stated amounts. Alternatively, the organophilic layered silicate can be used in the form of a concentrated mixture of the layered silicate (masterbatch). In the concentrated mixture, the organophilic layered silicate is present in a polymer, preferably in the same polymer to which the layered silicate is added. The concentrated mixture may have a concentration of 5 to 40% by weight of phyllosilicate based on the polymer contained in the concentrated mixture. The concentrated mixture is added to the polymer in an amount corresponding to a content of the organophilic layer silicate in the polymer of 0.01 to 5.00 wt .-%, more preferably to a content of the organophilic layer silicate in the polymer of 0.05 to 3, 00 wt .-%, based on the polymer leads.

In the process of antimicrobial finishing of a polymer of the present invention, the polymer is preferably in the form of films, fibers or moldings, e.g. Injection molded bodies obtained.

The polymer obtained in this way can be used, for example, as packaging material, in particular as packaging material for foodstuffs. medium, cosmetics and medicines. Furthermore, the antimicrobial polymer can be used for the production of clothing (especially workwear and sportswear), home textiles (eg bedding, curtains and towels), automotive textiles (eg seat covers), technical textiles (eg screens and filters) as well as hygiene and medical products ( eg toothbrushes, diapers, sanitary napkins, surgical sutures). Polymers obtained as moldings can be used, for example, in the production of furniture for equipping hospitals and medical practices.

Surprisingly, the process according to the invention leads to the antimicrobial activity of the onium ions contained in the organophilic layered silicate being retained in the polymer. At the same time, the antimicrobial onium ions are immobilized in the polymer due to their attachment to the layered silicate so that the onium ions can not migrate out of the polymer. Thus, permanent antimicrobial efficacy is ensured without resulting in adverse health effects (e.g., skin irritation or allergies). An overlay of the layered silicate beyond its cation exchange capacity, in particular the treatment of the layered silicate in at least two successive stages (see above), is particularly advantageous for long-term antimicrobial activity. This may, without the invention being limited to this assumption, being due to the different bonding of the onium ions or the additional antimicrobially active substance applied beyond the cation exchange capacity.

The advantageous preservation of the antimicrobial activity of the immobilized onium ions in the polymer is probably also due, inter alia, to the fact that by the mixing of the polymer and the organophilic layered silicate is achieved under at least partially exfoliating conditions, a distribution of the organophilic layer silicate in the polymer in the nanoscale. That is, the antimicrobial onium ions contained in the layered silicate are present in high singulation and even distribution in the polymer, particularly at the polymer surfaces, thereby providing high antimicrobial efficacy of the finished polymer.

A further aspect of the present invention thus relates to the use of an organophilic layered silicate as described herein for the antimicrobial finish of a polymer or a polymer composition, in particular in the exfoliated state.

Further aspects of the invention relate to an antimicrobial plastic additive and an antimicrobial polymer composition containing an organophilic layered silicate as described herein.

Show it:

Fig. 1 shows the result of the WAXS examination of the antimicrobially finished polymer according to Example 2;

For comparison, FIG. 2 shows the result of the WAXS examination of a mixture of polymer powder and the organophilic phyllosilicate according to Example 2 in the same concentration ratios; FIG. 3 shows, for comparison, the result of the WAXS examination of the pure organophilic layered silicate according to Example 2.

Unless otherwise stated, the particle size distribution was determined according to Malvern. This is a common procedure. A Mastersizer from Malvern Instruments Ltd, UK was used according to the manufacturer's instructions. The measurements were carried out with the intended dry powder feeder in air and the values related to the sample volume were determined. 100% by volume of the particles are below the Dχoo value; 90% by volume of the particles are below the D ₉₀ value.

Unless otherwise stated, Bruker's "D8 Advance" system with a horizontal tube goniometer was used for the X-ray structure investigations (WAXS) .The measurements were carried out in the transmission method and the step size measured was 2 theta = 0.05 ° The counting time was 5 seconds and the source of radiation was a CuKa radiation with Ni filter.

The invention will now be explained in more detail by means of the following non-limiting examples:

Comparative Example 1

100 g of a purified sodium bentonite (Nanofil 757, Süd-Chemie AG) the cation exchange capacity (CEC) 80 meq / 100g is, swollen in 6000 ml of water with stirring at 60 ⁰ C over a period of 30 minutes. To this suspension gradually becomes a solution while stirring continuously of 8.6 g of tetramethylammonium chloride in 1000 ml of water. After completion of the addition is stirred at 60 ⁰ C for 4 hours. The relatively rapidly forming organophilic layered silicate settles out of the aqueous phase slightly. It is separated by filtration from the aqueous phase, pre-dried oven at 80 ⁰ C in a forced-air drying oven and then dried at 80 ⁰ C for 5 hours in Vakuumtro-. Subsequently, the filter cake is ground to a particle size Di _oo <40 microns. 50 g of this ground powder are then placed in a Werner & Pfleiderer Z kneader and mixed there with a mixture of 20 g of n-hexane and 0.5 Hinokitiol (4-isopropyl-2-hydroxy-2,4, 6-Cycloheptatrien- l-on) at room temperature for 30 minutes at room temperature. Subsequently, the still moist mixture is removed from the Werner & Pfleiderer kneader and dried in a vacuum oven at 50 ⁰ C over a period of 12 hours. Subsequently, the dried material is ground to a particle size Dioo <40 microns.

example 1

To prepare an organophilic phyllosilicate 100 g of a purified, natural sodium montmorillonite (Nanofil 757 Süd-Chemie AG), whose cation exchange capacity is 80 meq / 100 g, in 6000 ml of water with stirring at 60 ⁰ C over a period of 30 minutes swollen. A solution of 30.6 g of benzyldimethyldodecylammonium chloride (Fluka Co., corresponding to 9OmVal) in 1000 ml of water is added gradually to this suspension, with continuous stirring. After completion of the addition is stirred at 60 ⁰ C for 4 hours. The relatively rapidly forming organophilic layered silicate settles from the aqueous phase slightly. It is separated by filtration from the aqueous phase, predried in a convection oven at 80 ⁰ C and then dried in a vacuum oven at 80 ⁰ C to a residual moisture content of less than 0.8%. The yield is 93.8%.

The dried organophilic phyllosilicate is ground in a centrifugal mill ZM 100 (Retsch GmbH & Co.) and the millbase is classified via a sieve, so that a particle size Dioo <40 microns is obtained. X-ray analysis (WAXS) shows a layer separation of 18.1 Å.

Example 2

To prepare an antimicrobially finished polyamide, 4.75 kg of polyamide 6 of the type Ponamid BS 300 (Unylon Polymers AG) are mixed with 250 g of the organophilic phyllosilicate prepared in Example 1 and, in the twin-screw extruder ZSK 25, granules containing 5% by weight of organophilic phyllosilicate , extruded. Here, the L / D ratio of the extruder is 40, the speed of the screw at 300 rpm, the throughput is 5 kg / h. The temperature is raised, starting at 230 ⁰ C in zone 1 to 250 ⁰ C in the exit zone (nozzle).

The exfoliation of the layered silicate in the nanocomposite (polymer) is checked by X-ray diffraction analysis (WAXS). It can be seen that no layer spacings can be determined, which means the complete exfoliation, see FIG. 1. If, in comparison, a mixture of polymer powder and organophilic phyllosilicate is prepared in the same concentration ratios and checked by X-ray diffraction (see FIG. Thus, the layer spacings as in pure organophilic layered silicate (see Figure 3) are determined. Example 2a

The procedure was as in Example 2 and an organophilic phyllosilicate prepared analogously to Example 1 was used, but only 20.4 g of benzyldimethyldodecylammonium chloride (Fluka Co., corresponding to 60 meq) were used in its preparation. The results are shown in Table 1.

Example 3

To produce a concentrated solution of the organophilic phyllosilicate (masterbatch), 0.9 kg of polyamide 6 of the type Ponamid BS 300 (Unylon Polymers AG) are mixed with the organophilic phyllosilicate prepared in Example 1 in an amount of 100 g and in a mini-extruder of Company "RandCastle" to a masterbatch granules containing 10 wt .-% organophilic layered silicate extruded.

The L / D ratio of the extruder is 25, the speed of the screw at 120 rpm, the throughput is about 1 kg / h. The temperature is raised, starting at 230 ⁰ C in zone 1 to 250 ⁰ C in the exit zone (nozzle).

To prepare an antimicrobially finished polyamide containing 1% by weight of organophilic phyllosilicate, 9 parts of polyamide 6 are mixed with 1 part of the masterbatch granules and extruded with the "RandCastle" mini-extruder Conditions selected as in the production of the masterbatch. The layer spacing of 18.1 Å, which the organophilic layer silicate of Example 1 shows in the WAXS investigation, can no longer be detected in the extrudate, which is proof of its exfoliation.

Comparative Example 3

To produce a concentrated solution of the organophilic phyllosilicate (masterbatch), 0.9 kg of polyamide 6 of the Ponamid BS 300 type (Unylon Polymers AG) are mixed with the organophilic phyllosilicate prepared in Comparative Example 1 in an amount of 100 g and added to a masterbatch granulate a content of 10% Organoclay extruded in a mini extruder from the company "RandCastle".

To prepare an antibacterially treated polyamide having an organoclay content of 1%, 9 parts of the polyamide 6 are mixed with 1 part of the masterbatch granules and extruded with the mini-extruder from the company "RandCastle" under the same conditions as in Example 3.

The result of the X-ray diffraction study (WAXS) shows that the interlayer distance of the organophilic layered silicate of 18.1 A remains unchanged compared to the starting material. This proves that there was no exfoliation of the phyllosilicates in the polymer matrix. Example 4

Analogously to Example 1, an organophilic phyllosilicate is prepared by cation exchange with benzyldimethyloctadecylammonium chloride (Aldrich). This quaternary salt per se exhibits a lower antimicrobial activity than the benzyldimethyldodecylammonium chloride used in Example 1.

Analogously to Example 2, polyamide 6 is antimicrobially finished with the resulting organophilic phyllosilicate.

Example 5

To prepare an organophilic phyllosilicate which is adsorptively loaded with quaternary onium ions beyond its cation exchange capacity, an organophilic phyllosilicate is first prepared according to Example 1, with the exception that dioctadecyldimethylammonium chloride is used as the onium compound instead of the benzyldimethyldodecylammonium chloride. 100 g of the organophilic phyllosilicate produced in this way are moistened with 90 ml of water and admixed with a solution of 16 g of benzyldimethyldodecylammonium chloride in 40 ml of water. The mixture is kneaded in the Werner & Pfleiderer kneader for 30 minutes and dried in a vacuum oven at 80 ⁰ C. The dried organophilic phyllosilicate is ground in a centrifugal mill ZM 100 (Retsch GmbH) and the millbase is classified via a sieve, so that a particle size D ₁₀ o <40 microns is obtained.

With this product, in analogy to Example 2, polyamide 6 is antimicrobially finished. Example 6

To prepare an organophilic layer silicate adsorbed over its cation exchange capacity with an antimicrobially active compound, 100 g of an organoclone prepared using benzyldimethyldodecylammonium chloride (Example 4) are moistened with 90 ml of water and treated with a solution of 4.4 g of 3 , δ-diamino-lO-methyl-acridinium chloride in 40 ml of water / ethanol. The mixture is kneaded for 30 minutes in a Werner & Pfleiderer kneader and dried in a vacuum cabinet at 80 ⁰ C. The dried organophilic phyllosilicate is ground in a centrifugal mill ZM 100 (Retsch GmbH) and the millbase is classified via a sieve, so that a particle size Dioo <40 microns is obtained. The result of the X-ray diffraction study (WAXS) shows an unchanged layer thickness of the organophilic phyllosilicate of 19 Å compared to the starting material.

This product is processed to a nanocomposite granules with an organoclay content of 1%.

Example 7

To produce a further organophilic layered silicate adsorbed over its cation exchange capacity with an antimicrobially active compound, 100 g of an organoclay prepared using benzyldimethyldodecylammonium chloride are moistened with 90 ml of water and admixed with a solution of 7.5 g triclosan in 40 ml isopropanol. The mixture is stirred for 30 minutes in the Werner & Pfleiderer kneader. kneads and dried in a vacuum oven at 80 ⁰ C. The dried organophilic phyllosilicate is ground in a centrifugal mill ZM 100 (Retsch GmbH) and the millbase is classified via a sieve, so that a particle size Di _oo <40 microns is obtained. The result of the X-ray structure investigation (WAXS) shows a layer spacing of the organophilic layer silicate of 19 Å, which is unchanged compared to the starting material.

Comparative Example 4

1000 g of a highly purified sodium bentonite (Nanofil 757 Süd-Chemie) are placed in a heating-cooling mixer from Henschel and then 120 g of triclosan, which is dissolved in 600 ml of isopropanol with stirring at a speed of 2000 revolutions per minute , dosed over a period of 5 minutes. It is stirred for a further 10 minutes, then the product is removed from the heating-cooling mixer and dried at 80 ⁰ C. The dried phyllosilicate is subsequently ground in a centrifugal mill ZM 100 (Retsch GmbH) and the millbase is classified via a sieve, so that a particle size D ₁₀ o <40 microns is obtained. X-ray analysis (WAXS) shows a layer spacing of 1.25 nm, which shows that there was no intercalation of the triclosan between the bentonite layers during the mixing process. To prepare an antibacterially treated polyamide having an organoclay content of 1%, 9 parts of the polyamide 6 are mixed with 1 part of the masterbatch granules and extruded with the mini-extruder from the company "RandCastle" under the same conditions as in Example 3. In order to determine the antimicrobial effectiveness of the antimicrobially finished polymers according to Examples 2, 4, 5, 6 and 7 and the polymers of Comparative Examples 3 and 4, samples of the granules produced are processed into films having a thickness of 0.05 to 0.1 mm. For comparison purposes, films of a thickness in the range from 0.05 to 0.1 mm are produced from the polyamide 6 of the type Ponamid BS 300 (Unylon Polymers AG) which does not contain an organophilic layered silicate used in Example 2. Test specimens are punched out of the films and subjected to a microbiological test. The test is carried out by applying the WST-I test described below. The test results are shown in Table 1.

WST-I-Test - Cell activity test for the detection of antimicrobial efficacy after a static incubation phase:

As test germs Escherichia coli and Staphylococcus aureus are used. The antimicrobially treated polymers in the form of round planar foil sections with a diameter of 15 mm (-0.5 mm) serve as test specimens. These specimens are inserted in multiwell plates. For sufficient statistical safety, 6 parallel tests shall be carried out using a total of 24 specimens per material configuration. The specimens inserted into the multiwell plates are inoculated with 1 ml each of a suspension whose bacterial density is 10 ⁷ nuclei / ml and incubated sterile for 48 hours. The specimens are then removed, cautiously rinsed in PBS to remove bacteria that are not adherent, and split for the analyzes (one sample for the WST-I test and one sample for fluorescence analysis for each parallel experiment). The analysis by WST-1-test takes place on the biofilms directly on the surface of the Specimen. The biofilm is not detached for this purpose. 1 mL of fresh WST-1 reagent (tetrazolium salt solution) is added and the specimens are further incubated in sealed vessels for 3 hours under static conditions. Subsequently, the photometric determination of the formazan formed by measuring the optical density of the media supernatant at 450 nm (against 690 nm) on the spectrophotometer, depending on the number of bacteria and their activity. For the analysis of the total number of adherent bacteria and the proportion of living to dead bacteria in the biofilm, the bacteria are detached from the sample surface by means of ultrasound, suspended and treated with selective fluorescence markers. The quantitative analysis of the living and dead bacteria is carried out by counting on the fluorescence microscope. The effectiveness of the antimicrobial polymer is assessed by comparing the totality of the analytical data for the organophilic phyllosilicate polymer and for the polymer without the phyllosilicate phyllosilicate.

Table 1

Table 1 shows the good antimicrobial activity of the products according to the invention. Allocation of the layered silicate with ammonium ions beyond the CEC leads to clearly advantageous results, see Example 2 compared to Example 2a. Also, the synergistic effect of the onium ions and an additional antimicrobial substance is evident, with the product of Example 7 giving the best results. Example 8

Granules are prepared analogously to Example 3, which contain the organophilic layer silicate obtained in Example 1 in different amounts in order to investigate the influence of the organophilic layer silicate on the textile-physical parameters of filaments.

The following phyllosilicate contents are set:

0.5% by weight

- 1.0% by weight - 2.0% by weight -%

The granules obtained are spun into filaments by means of a melt spinning apparatus at a take-off of 1000 m / min. After the stretching process, filaments of a fineness of 35 dtex f12 result. Under the same conditions also filaments of granules of Example 2 (content of organophilic phyllosilicate 5 wt.%) And of polyamide 6, which does not contain organophilic phyllosilicate prepared.

Table 2 shows the influence of the different contents of organophilic phyllosilicate on the textile-physical parameters:

Table 2

It turns out that only then a significant improvement of the initial modulus of the fibers can be observed, when the organically modified phyllosilicates exfoliate in the polymer material. If this exfoliation does not occur (Comparative Example 3), a significant deterioration in the elongation at break is observed without the initial modulus increasing significantly.

Example 9

For the preparation of an antimicrobially treated polyethylene terephthalate, 4.975 kg of polyethylene terephthalate having an intrinsic viscosity of 0.663 are mixed with the organophilic layer silicate from Example 1 in an amount of 25 g, and in Twin-screw extruder ZSK 25 extruded into granules containing 0.5 wt .-% organophilic layered silicate.

Here, the L / D ratio of the extruder is 40, the speed of the screw at 300 rpm, the throughput is 5 kg / h. The temperature is raised, starting at 230 ⁰ C in zone 1 to 270 ⁰ C in the exit zone (nozzle).

The layer spacing of 18.1 A, which is shown by the organophilic layered silicate from Example 1 in the WAXS investigation, is no longer detectable in the extrudate, which is proof of its exfoliation.

To determine the antimicrobial efficacy of the polyethylene terephthalate treated in this way, a sample of the granules produced and a sample of the polyethylene terephthalate used which does not contain an organophilic layered silicate are processed into films with a thickness of 0.05 to 0.1 mm. Test specimens are punched out of these films and subjected to a microbiological test. The test is carried out by using the WST-1 test (see Example 7). As test germs Escherichia coli and Staphylococcus aureus are used. The test specimens of the antimicrobially treated polyethylene terephthalate show a reduced total number of adhering bacteria to those of the starting polymer for both bacterial species. The reduction in bacterial counts is 53% on average (E. coli) and 65% (S. aureus) and is significant for both species.

Determination of antimicrobial effectiveness after simulated weathering with artificial sweat solution To prepare a polyamide masterbatch with antimicrobially active layer silicates, 0.9 kg of Pronamid BS 300 type polyamide 6 are first mixed with 100 g of the organophilic layered silicate analogously to Example 3 and converted into a masterbatch in a miniature extruder from RandCastle. Granules containing 10 wt .-% organophilic layered silicate extruded.

The organophilic sheet silicates were prepared analogously to Example 1, with the following difference:

Example 10: Use of 44.2 g of hexadecylpyridinium chloride instead of 30.6 g of benzyldimethyldodecylammonium chloride;

Example 11: Use of 47.8 g of benzyldimethyltetradecylammonium chloride instead of 30.6 g of benzyldimethyldodecylammonium chloride;

Example IIa: Use of 22.08 g of benzyldimethyltetradecylammonium chloride (60 meq) in place of 30.6 g of benzyldimethyldodecylammonium chloride;

Example 12 Analogously to Example 1, an organophilic phyllosilicate is prepared by cation exchange with a mixture of 29.4 g of benzyldimethyltetradecylammonium chloride and 17 g of hexadecylpyridinium chloride. Both quaternary ammonium compounds are dissolved together in 1000 ml of water and processed analogously to Example 1 with the bentonite.

EXAMPLE 13 (2-stage process, otherwise identical onium compounds as Example 12): To produce an organophilic layered silicate having an antimicrobially active, adsorptively loaded, organophilic sheet silicate in excess of its cation exchange capacity, 100 g of an organoclone prepared using 29.4 g of benzyldimethyl-tetradecylammonium chloride (Example 4) moistened with 20 ml of water and then treated with a solution of 17 g Hexadecylpyridiniumchlorid in 60 ml of water.

Furthermore, the materials according to Examples 6 and 7 were used.

To produce antimicrobial test films, the RandCastle mini-extruder is equipped with a 0.8 mm x 50 mm film die and a mixture of 10% phyllosilicate masterbatch and 90% polyamide 6 is further processed. The temperatures were in zone 1 at 255, in zone 2 at 260 and in zone 3 at 265 ° C. The pressure varied between 60 and 80 bar, the rotational speed of the extruder shaft was 50 U / min. The thickness of the film thus produced varied between 0, 5 and 0, 6 mm.

Test strips of 2 cm width and 15 cm length are cut out of the polyamide 6 films produced in this way. About a rectangular plastic tub using a suitable device, the plastic test strips are clamped vertically, without touching each other. A total of 64 test strips were attached in the test apparatus.

All test strips were then sprayed every 24 hours with 2 liters of artificial welding solution according to DIN EN 1811. The spraying took place with the help of a plastic flower syringe at room temperature. The entire spraying process took about 5 minutes. After spraying 14 times a day, all test strips were sprayed with a total of 5 liters of demineralized water. Connection was made over a further 14 days Liehe spraying with artificial welding solution. Finally, all test strips were again sprayed with 5 liters of demineralized water and then subjected to the Zeilaktivitätstest WST 1.

The results of this cell activity test are shown in the following Table 3, whereby the advantages of over-coating of the layered silicate with onium ions and the 2-stage process are also evident.

Table 3 Cell activity test after aging

Claims

A process for the antimicrobial finishing of a polymer, characterized in that a) an organophilic layered silicate containing antimicrobial onium ions is prepared, wherein an initial layer silicate is loaded with onium ions to an extent exceeding the cation exchange capacity of the Starting layer silicate goes out; b) the organophilic layered silicate is mixed with the polymer, and c) preferably the polymer is not provided with antimicrobially active metals or metal compounds.

2. The method according to claim 1, characterized in that the organophilic layered silicate according to step a) is additionally treated with at least one antimicrobial substance, in particular selected from antimicrobial onium ions and / or at least one non-ionic antimicrobial substance.

3. The method according to any one of the preceding claims, characterized in that the at least one non-ionic antimicrobial substance is selected from the group consisting of: isothiazolines, isothiazolones such as octhilinone (2-octyl-3 (2H) -isothiazolone) or 4 , 5-dichloro-2-octyl-3 (2H) -isothiazolin-3-one (DCOIT), carbamate derivatives such as 3-iodo-2-propynyl-N-butylcarbamate, halogen-containing sulfonamides such as chloramine T (N-chloro-4 toluene sulfonic acid amide - Na salt), halogenated phenol derivatives such as tebuconazole (1- (4-chloro) phenyl) -4,4-dimethyl-3- (IH-1,2,4-triazol-1-ylmethyl) -3-pentanol), triclocarban (N- (4-chlorophenyl-N '(3, 4-dichloro) phenyl) urea) or triclosan (5-chloro-2- (2,4-dichlorophenoxy) phenol), or mixtures thereof.

4. The method according to any one of the preceding claims, characterized in that the polymer is a thermoplastic polymer.

5. The method according to any one of the preceding claims, characterized in that the thermoplastic polymer is a polyester, a polyamide or a polyacrylonitrile.

6. The method according to any one of the preceding claims, characterized in that the organophilic layered silicate containing anti-microbially active onium ions is prepared by a starting layer silicate is subjected to a cation exchange with antimicrobial onium ions.

7. The method according to claim 6, characterized in that as starting layer silicate a montmorillonite, hectorite, illite, vermiculite, beidellite, nontronite, Volkonskoit, Saukonit and / or saponite is used.

8. The method according to claim 7, characterized in that is used as starting layer silicate natural sodium montmorillonite.

9. The method according to any one of claims 6 to 8, characterized in that the cation exchange or the treatment of the organophilic starting layer silicate and / or the organophilic layered silicate using one or more anti microbially active quaternary ammonium compounds is performed.

10. The method according to claim 9, characterized in that the quaternary ammonium compounds are selected from compounds of the formula

[R ₁ R ₂ R ₃ R ₄ N ⁺ ] X ^"

wherein Ri, R ₂ and R ₃ independently represent an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 12 carbon atoms or an aralkyl group having 6 to 12 carbon atoms, R _{4 represents} an alkyl group having 10 to 18 carbon atoms Atoms and X ^"is a fluoride, chloride, bromide or iodide.

11. Process according to claim 10, characterized in that the quaternary ammonium compounds are selected from benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, benzyldimethyloctadecylammonium chloride, dicadecyldimethylammonium chloride, dioctadecyldimethylammonium chloride and hexadecyltrimethylammonium chloride.

12. The method according to any one of claims 6 to 8, characterized in that the cation exchange or the treatment of the starting layer silicate and / or the organophilic Schichtsili- cats is carried out using one or more antimicrobial pyridinium compounds.

13. The method according to claim 12, characterized in that the antimicrobial pyridinium compounds selected are from dodecylpyridinium chloride, hexadecylpyridinium chloride, acriflavinium chloride and dequalinium chloride.

14. The method according to any one of claims 6 to 8, characterized in that the cation exchange or the treatment of the Ausgangsschichtsilicat and / or the organophilic Schichtsili- cats is carried out using one or more antimicrobial quaternized guanidine derivatives and / or quaternized ssfonamidderivate.

15. A method according to any one of the preceding claims, characterized in that the starting layer silicate is loaded with onium ions to an extent corresponding to about 100 to 250%, in particular 100 to 200% of the cation exchange capacity of the starting layer silicate.

16. The method according to any one of the preceding claims, characterized in that the organophilic layered silicate exfoliates in the mixing with the polymer or at least partially exfoliated.

17. A process according to any one of claims 1 to 16, characterized in that the polymer is mixed with the organophilic phyllosilicate by co-extruding the polymer and the organophilic phyllosilicate.

18. A process according to any one of claims 1 to 16, characterized in that the polymer is mixed with the organophilic phyllosilicate by adding the organophilic phyllosilicate to the monomers of the polymer before or during the polymer synthesis.

19. The method according to any one of claims 1 to 18, characterized in that the organophilic layered silicate is added to the polymer in an amount of 0.01 to 5.00 wt.%, Based on the polymer.

20. The method according to any one of claims 1 to 19, characterized in that the antimicrobially finished polymer is obtained in the form of films, fibers or moldings.

21. Use of an organophilic layered silicate as defined in the preceding claims, in particular in the exfoliated state, for the antimicrobial finish of a polymer or of a polymer composition.

22. An antimicrobial plastic additive containing an organophilic layered silicate as defined in the preceding claims.

23. Antimicrobial plastic additive according to claim 22, characterized in that the organophilic layered silicate according to step a) of claim 1 is additionally treated or coated with at least one nonionic antimicrobial substance.

24. An antimicrobial polymer composition containing an organophilic layered silicate as defined in the preceding claims, in particular in the exfoliated state.