AU7236300A - Microbicidal copolymers - Google Patents

Description

WO 00/69934 PCT/EPOO/02781 Microbicidal copolymers The invention relates to antimicrobial polymers obtained by copolymerizing two or more aliphatically 5 unsaturated monomers which have been at least singly functionalized by means of a secondary amino group. The invention further relates to a process for preparing the antimicrobial polymers, and to their use. 10 The invention also relates to antimicrobial polymers obtained by graft polymerizing on a substrate, aliphatically unsaturated monomers which have been at least singly functionalized by means of a secondary amino group, and also to a process for their 15 preparation of these and to their use. It is highly undesirable for bacteria to become established or to spread on the surfaces of pipelines, containers or packaging. Frequently, slime layers form 20 and permit sharp rises in microbial populations, and these can lead to persistent impairment of the quality of water, drinks or foods, and even to spoilage of the product and harm to the health of consumers. 25 Bacteria must be kept away from all fields of life in which hygiene is important. This affects textiles for direct body contact, especially in the genital area, and for the care of the elderly and sick. Bacteria must also be kept away from surfaces of furniture and 30 instruments in wards, especially in areas for intensive care and neonatal care, in hospitals, especially in areas for medical interventions, and in isolation wards for critical cases of infection, and also in toilets. 35 A current method of treating equipment, or the surfaces of furniture or textiles, to resist bacteria either when this becomes necessary or else as a precautionary measure, is to use chemicals or solutions of mixtures of these which as disinfectans have a fairly broad -2 general antimicrobial action. Chemical agents of this type act nonspecifically and are frequently themselves toxic or irritant, or form degradation products which are hazardous to health. In addition, people frequently 5 exhibit intolerance to these materials once they have become sensitized. Another method to counteract surface spread of bacteria is to incorporate substances with antimicrobial action 10 into a matrix. Tert-butylaminoethyl methacrylate is a commercially available monomer in methacrylate chemistry and is used in particular as a hydrophilic constituent in 15 copolymerizations. For example, EP-B 0 290 676 uses various polyacrylates and polymethacrylates as a matrix for immobilizing bactericidal quaternary ammonium compounds. 20 In another technical sector US-A 4 532 269 discloses a terpolymer of butyl methacrylate, tributyltin methacrylate and tert-butylaminoethyl methacrylate. This polymer is used as an antimicrobial paint for ships: the hydrophilic tert-butylaminoethyl 25 methacrylate promotes gradual erosion of the polymer, thus liberating the highly toxic tributyltin methacrylate as antimicrobial agent. In these applications the copolymer prepared using 30 aminomethacrylates is merely a matrix or carrier substance for added microbicidal agents which can diffuse or migrate out of the carrier substance. Sooner or later polymers of this type lose their effectiveness once the "minimal inhibitory concentration" (MIC) is no 35 longer achieved on the surface. European Patent Applications 0 862 858 and 0 862 859 have disclosed that homo- and copolymers of tert butylaminoethyl methacrylate with a methacrylate having -3 a secondary amino function have inherent microbicidal properties. To avoid undesirable resistance phenomena in the microbes, particularly bearing in mind the development of resistance by bacteria known from 5 antibiotics research, systems developed in the future will need to continue to be based on novel compositions and have improved effectiveness. The object of the present invention is therefore to 10 develop novel polymers having antimicrobial action. These, where appropriate in the form of a coating, should prevent the establishment and spread of bacteria on surfaces. 15 Surprisingly, it has now been found that copolymerizing two or more components of aliphatically unsaturated monomers which have been at least singly functionalized by means of a secondary amino group, or graft polymerizing these components on a substrate, gives 20 polymers with a long-lasting microbicidal surface which is not attacked by solvents or by physical stresses and which does not exhibit migration. This makes it unnecessary to use other biocides. 25 The present invention therefore provides antimicrobial polymers obtained by copolymerizing (component I) aliphatically unsaturated monomers which have been at least singly functionalized by means of a secondary amino group with (component II) another aliphatically 30 unsaturated monomer which has been at least singly functionalized by means of a secondary amino group, where component I and component II are different from one another. 35 The present invention also provides a process for preparing antimicrobial polymers obtained by graft copolymerizing (component I) aliphatically unsaturated monomers which have been at least singly functionalized by means of a secondary amino group with (component II) -4 another aliphatically unsaturated monomer which has been at least singly functionalized by means of a secondary amino group, where components I and II are different from one another. 5 The copolymerization according to the invention of (components I and II) aliphatically unsaturated monomers which have been at least singly functionalized by means of a secondary amino group can also be carried 10 out with (component IIT) another aliphatically unsaturated monomer, with substantial retention of the microbicidal action. Suitable comonomer building blocks, besides the 15 secondary-amino-functionalized acrylates and methacrylates described in European Applications 0 862 858 and 0 862 859, are any aliphatically unsaturated monomers which have at least one secondary amino function, for example ethyl 3-phenylmethylamino 20 2-butenoate, ethyl 3-ethylamino-2-butenoate, ethyl 3-methylamino-2-butenoate, 3-methylamino-l-phenyl-2 propen-l-one, N-4-methylamino-1-anthraquinoyl(2 methyl)acrylamide, N-9,10-dihydro-4-(4-methylphenyl amino)-9,10-dioxo-l-anthraquinyl-2-methylpropenamide, 25 propyl 2-hydroxy-3-(3-triethoxysilylpropylamino)-2 propenoate, 1-(1-methylethylamino)-3-(2-(2-propenyl) phenoxy)-2-propanol hydrochloride, ethyl 3-phenylamino 2-butenoate, 1-(1-methylethylamino)-3-(2-(2 propenyloxy)phenoxy)-2-propanol hydrochloride, methyl 30 2-acrylamido-2-methoxyacetate, methyl 2-acetamido acrylate, N-tert-butylacrylamide, 2-hydroxy-N-2 propenylbenzamide and N-methyl-2-propenamide. The aliphatically unsaturated monomers of components I 35 or II used according to the invention and at least singly functionalized by means of a secondary amino group may have a hydrocarbon radical of up to 50 carbon atoms, preferably up to 30 carbon atoms, particularly preferably up to 22 carbon atoms. The substituents of -5 the amino group may be aliphatic or vinylic hydrocarbon radicals, such as methyl, ethyl, propyl or acrylic radicals, or cyclic hydrocarbon radicals, such as substituted or unsubstituted phenyl or cyclohexyl 5 radicals having up to 25 carbon atoms. The amino group may also have substitution by keto or aldehyde groups, such as acryloyl or oxo groups. To achieve a sufficient rate of polymerization, the 10 monomers of components I or II used according to the invention should have a molar mass of less than 900, preferably less than 550 g/mol. In a particular embodiment of the present invention the 15 components I or II used may comprise aliphatic unsaturated monomers functionalized by means of a secondary amino group and having the general formula RiNR 2 H 20 where Ri is a branched, unbranched or cyclic, saturated or unsaturated hydrocarbon radical having up to 50 carbon atoms which may have substitution by 0 atoms, 25 N atoms or S atoms, and

R

2 is a branched, unbranched or cyclic, saturated or unsaturated hydrocarbon radical having up to 25 carbon atoms, which may have substitution by 0 atoms, 30 N atoms or S atoms. The monomers of components I and II must be different, and the molar mass difference between these monomers may therefore be at least 23 g/mol. Examples of 35 combinations of monomers of components I, II and, where appropriate, III are described in the examples. The novel antimicrobial copolymers may also be obtained by copolymerizing components I and II or, respectively -6 I, II and III, on a substrate. This gives a physisorbed coating made from the antimicrobial copolymer on the substrate. 5 Suitable substrate materials are especially any of the polymeric plastics, such as polyurethanes, polyamides, polyesters and polyethers, polyether block amides, polystyrene, polyvinyl chloride, polycarbonates, polyorganosiloxanes, polyolefins, polysulfones, 10 polyisoprene, polychloroprene, polytetrafluoroethylene (PTFE) or corresponding copolymers or blends, or also naturally occurring or synthetic rubbers, with or without radiation-sensitive groups. The novel process may also be used on surfaces of objects made from 15 metal, from glass or from wood and surface-coated or otherwise coated with plastic. In another embodiment of the present invention the copolymers may be prepared by graft polymerizing a 20 substrate with the components I and II or, respectively, with the components I, II and III. The grafting of the substrate allows covalent linking of the antimicrobial copolymer to the substrate. Substrates which may be used are any polymeric 25 material, such as the plastics mentioned above. Prior to the graft polymerization, the surfaces of the substrate may be activated by a variety of methods. Any standard method for activating polymer surfaces may be 30 used here, for example the substrate may be activated prior to the graft polymerization by UV radiation, plasma treatment, corona treatment, flame treatment, ozonization, electrical discharge or y-radiation. The surfaces are usefully freed in advance in a known 35 manner from oils, fats or other contamination, using a solvent. The substrate may be activated using UV radiation in the wavelength range from 170 to 400 nm, preferably -7 from 170 to 250 nm. An example of a suitable radiation source is a Noblelight UV excimer apparatus from HERAEUS, Hanau, Germany. However, mercury vapor lamps are also suitable for substrate activation as long as 5 they emit substantial proportions of radiation in the abovementioned ranges. The exposure time is generally from 0.1 seconds to 20 minutes, preferably from 1 second to 10 minutes. 10 The activation of the standard polymers with UV radiation may moreover also use a photosensitizer. For this, the photosensitizer, such as benzophenone, is applied to the substrate surface and irradiated. A mercury vapor lamp may again be used here, with 15 exposure times of from 0.1 seconds to 20 minutes, preferably from 1 second to 10 minutes. According to the invention, the activation may also be by plasma treatment using an RF or microwave plasma 20 (Hexagon, Technics Plasma, 85551 Kirchheim, Germany) in air, nitrogen or argon atmospheres. The exposures times are generally from 2 seconds to 30 minutes, preferably from 5 seconds to 10 minutes. The energy supplied in the case of laboratory devices is from 100 to 500 W, 25 preferably from 200 to 300 W. Corona devices (SOFTAL, Hamburg, Germany) may also be used for activation. The exposure times in this case are generally from 1 to 10 minutes, preferably from 1 30 to 60 seconds. Activation by electrical discharge, electron beam or y radiation (e.g. from a cobalt 60 source), and also ozonization, allow short exposure times, generally from 35 0.1 to 60 seconds. Substrate surfaces may also be activated by flame treatment. Suitable devices, in particular those with a barrier flame front, can readily be constructed or, for example, purchased from ARCOTEC, 71297 M6nsheim, Germany. They may be operated using hydrocarbons or hydrogen as combustion gas. In all cases it is necessary to avoid damage to the substrate by 5 overheating, and this can readily be ensured if the side of the substrate facing away from the flame treatment side is in intimate contact with a cooled metal surface. Activation by flame treatment is therefore restricted to relatively thin, sheet-like 10 substrates. The exposure times are generally from 0.1 second to .1 minute, preferably from 0.5 to 2 seconds and the flames are exclusively nonluminous, and the distances between the substrate surfaces and the outer side of the flame front are from 0.2 to 5 cm, 15 preferably from 0.5 to 2 cm. The substrate surfaces activated in this way are coated by known .methods, such as dipping, spraying or spreading, with (component I) aliphatically unsaturated 20 monomers which have been at least singly functionalized by means of a secondary amino group with (component II) one or more aliphatically unsaturated monomers of which at least one has been functionalized by means of a secondary amind group, where appropriate in solution, 25 where component I and component II are different from one another. Solvents which have proven useful are water and water/ethanol mixtures, but other solvents may also be used as long as they are sufficiently capable of dissolving the monomers and give good 30 wetting of the substrate surfaces. Solutions with monomer contents of from 1 to 10% by weight, for example about 5% by weight, have proven successful in practice and generally give, in a single pass, coherent coatings which cover the substrate surface and have 35 thicknesses which can be more then 0.1 pm. The graft copolymerization of the monomers applied to the activated surfaces may usefully be initiated by radiation in the short-wave segment of the visible -9 range or in the long-wave segment of the UV range of electromagnetic radiation. For example, the radiation from a UV excimer of wavelengths from 250 to 500 nm, preferably from 290 to 320 nm, is very suitable. 5 Mercury vapor lamps are also suitable here as long as they have substantial proportions of radiation in the abovementioned ranges. The exposure times are generally from 10 seconds to 30 minutes, preferably from 2 to 15 minutes. 10 Graft copolymerization of the novel comonomer compositions can also be achieved by a process described in European Patent Application 0 872 512 and based on a graft polymerization of monomer molecules 15 and initiator molecules incorporated by swelling. The monomer used for the swelling process may be component III. Even without grafting to a substrate surface, the novel 20 antimicrobial copolymers made from aliphatically unsaturated monomers which have been at least singly functionalized by means of a secondary amino group with (components I and II) and optionally (component III) another aliphatically unsaturated monomer, where 25 component I and component II are different from one another, show microbicidal or antimicrobial behavior. Another embodiment of the present invention consists in carrying out the copolymerization of components I and 30 II or I, II and II [sic], where components I and II are different from one another, on a substrate. Components I, II and, where appropriate, III may be applied to the substrate in solution. Examples of 35 suitable solvents are water, ethanol, methanol, methyl ethyl ketone, diethyl ether, dioxane, hexane, heptane, benzene, toluene, chloroform, dichloromethane, tetrahydrofuran and acetonitrile. Component III may also serve as solvent for components I and II.

- 10 Component III may comprise any aliphatically unsaturated monomers which enter into copolymerization with components I and II. Component III may also 5 comprise other aliphatically unsaturated monomers which have been at least singly functionalized by means of a secondary amino group, and in this case components I, II and III are all different from one another. In addition, component III may also comprise acrylates or 10 methacrylates, e.g. acrylic acid, tert-butyl methacrylate, methyl methacrylate, styrene, vinyl chloride, vinyl ethers, acrylamides, acrylonitriles, olefins (ethylene, propylene, butylene and isobutylene), allyl compounds, vinyl ketones, 15 vinylacetic acid, vinyl acetates or vinyl esters. The novel antimicrobial copolymers may also be used directly, i.e. not by polymerizing the components on a substrate, but as an antimicrobial coating. Suitable 20 coating methods are application of the copolymers in solution or as a melt. The solution of the novel polymers may be applied to the substrates' by, for example, dipping, spraying or 25 painting. If the novel polymers are produced directly on the substrate surface without grafting, conventional free radical initiators may be used. 30 Examples of initiators which may be used are azonitriles, alkyl peroxides, hydroperoxides, acyl peroxides, peroxoketones, peresters, peroxocarbonates, peroxodisulfate, persulfate and any of the usual 35 photoinitiators, such as acetophenones, a hydroxyketones, dimethylketals and benzophenone.

- 11 The polymerization may also be initiated thermally or, as already stated, by electromagnetic radiation, such as UV light or y-radiation. 5 The novel antimicrobial polymers may also be used as components for formulating paints and surface coatings. Use of the modified polymer substrates The present invention also provides the use of the 10 novel antimicrobial polymers to produce antimicrobially active products, and the products per se which are produced in this way. The products may comprise polymer substrates modified according to the invention or consist of these. Products of this type are preferably 15 based on polyamides, polyurethanes, polyether block amides, polyesteramides or -imides, PVC, polyolefins, silicones, polysiloxanes, polymethacrylate or polyterephthalates surface-modified using novel polymers. 20 Examples of antimicrobially active products of this type are in particular machine parts for processing food and drink, components in air-conditioning systems, roofing, items for bathroom and toilet use, kitchen 25 items, components of sanitary equipment, components of cages or houses for animals, recreational products for children, components of water systems, packaging for food or drink, operator units (touch panels) of devices, and contact lenses. 30 The present invention also provides the use, to produce hygiene products or items in medical technology, of the polymer substrates whose surfaces have been modified using the polymers or processes of the invention. That 35 which has been said above concerning preferred materials applies correspondingly. Examples of hygiene products of this type are toothbrushes, toilet seats, combs and packaging materials. The term hygiene items also includes objects which may come into contact with - 12 a large number of people, such as telephone handsets, stair rails, door handles, window catches, and grab straps and grab handles in public conveyances. Examples of items in medical technology are catheters, tubing, 5 protective or backing films and also surgical instruments. The novel. copolymers or graft polymers may be used anywhere where importance is placed on surfaces with 10 release properties or surfaces which are very free from bacteria, i.e. microbicidal. Examples of application of the novel copolymers or graft polymers are in particular surface coatings, protective paints and other coatings in the following sectors: 15 0 Marine: Boat hulls, docks, buoys, drilling platforms, ballast water tanks 0 Construction: Roofing, basements, walls, facades, greenhouses, sun protection, garden fencing, wood 20 protection * Sanitary: Public conveniences, bathrooms, shower curtains, toilet items, swimming pool, sauna, jointing, sealing compounds * Requisites for daily life: Machines, kitchen, 25 kitchen items, sponge pads, recreational products for children, packaging for food or drink, milk processing, drinking water systems, cosmetics * Machine parts: Air-conditioning systems, ion exchangers, process water, solar-powered units, 30 heat exchangers, bioreactors, membranes e Medical technology: Contact lenses, diapers, membranes, implants * Consumer articles: Automobile seats, clothing (socks, sport clothing), hospital equipment, door 35 handles, telephone handsets, public conveyances, animal cages, cash registers, wall-to-wall carpets, wallpapers.

- 13 The following examples are given in order to describe the present invention in greater detail, but are not intended to limit its scope as set out in the claims. 5 Example 1: 5 g of methyl 2-acrylamido-2-methoxyacetate (Aldrich), 5 g of methyl 2-acetamidoacrylate (Aldrich) and 55 ml of ethanol are charged to a three-necked flask and heated to 650C under a stream of argon. 0.14 g of 10 azobisisobutyronitrile dissolved in 4 ml of ethyl methyl ketone is then slowly added dropwise, with stirring. The mixture is heated to 70"C and stirred for 72 h at this temperature. After this time the reaction mixture is stirred into 0.5 1 of n-hexane, whereupon 15 the polymeric product precipitates. After the product has been filtered off the filter residue is washed with 100 ml of n-hexane to remove any residual monomers still present. The product is then dried in vacuo for 24 hours at 50 0 C. 20 Example la: 0.05 g of the product from Example 1 are shaken in 20 ml of a test microbial suspension of Staphylococcus aureus. After a contact time of 30 minutes, 1 ml of the 25 test suspension is removed and the number of microbes in the test mixture is determined. After expiry of this time the number of microbes has fallen from 107 to 10 3 . Example lb: 30 0.05 g of the product from Example 1 are shaken in 20 ml of a test microbial suspension of Pseudomonas aeruginosa. After a contact time of 60 minutes, 1 ml of the test suspension is removed and the number of microbes in the test mixture is determined. After 35 expiry of this time the number of microbes has fallen from 107 to 104.

- 14 Example 2: 5 g of methyl 2-acrylamido-2-methoxyacetate (Aldrich), 3 g of N-tert-butylacrylamide (Aldrich) and 55 ml of ethanol are charged to a three-necked flask and heated 5 to 65 0 C under a stream of argon. 0.12 g of azobisisobutyronitrile dissolved in 4 ml of ethyl methyl ketone is then slowly added dropwise, with stirring. The mixture is heated to 70 0 C and stirred for 72 h at this temperature. After this time the reaction 10 mixture is stirred into 0.5 1 of n-hexane, whereupon the polymeric product precipitates. After the product has been filtered off the filter residue is washed with 100 ml of n-hexane to remove any residual monomers still present. The product is then dried in vacuo for 15 24 hours at 50*C. Example 2a: 0.05 g of - the product from Example 2 are shaken in 20 ml of a test microbial suspension of Staphylococcus 20 aureus. After a contact time of 30 minutes, 1 ml of the test suspension is removed and the number of microbes in the test mixture is determined. After expiry of this time the number of microbes has fallen from 10 7 to 103. 25 Example 2b: 0.05 g of the product from Example 2 are shaken in 20 ml of a test microbial suspension of Pseudomonas aeruginosa. After a contact time of 60 minutes, 1 ml of the test suspension is removed and the number of 30 microbes in the test mixture is determined. After expiry of this time the number of microbes has fallen from 107 to 103. Example 3: 35 4 g of methyl 2-acetamidoacrylate (Aldrich), 5 g of N tert-butylacrylamide (Aldrich) and 65 ml of ethanol are charged to a three-necked flask and heated to 65 0 C under a stream of argon. 0.15 g of azobisiso butyronitrile dissolved in 5 ml of ethyl methyl ketone - 15 is then slowly added dropwise, with stirring. The mixture is heated to 700C and stirred for 72 h at this temperature. After this time the reaction mixture is stirred into 0.5 1 of n-hexane, whereupon the polymeric 5 product precipitates. After the product has been filtered off the filter residue is washed with 100 ml of n-hexane to remove any residual monomers still present. The product is then dried in vacuo for 24 hours at 500C. 10 Example 3a: 0.05 g of the product from Example 3 are shaken in 20 ml of a test microbial suspension of Staphylococcus aureus. After a contact time of 15 minutes, 1 ml of the 15 test suspension is removed and the number of microbes in the test mixture is determined. After expiry of this time no Staphylococcus aureus microbes are now detectable. 20 Example 3b: 0.05 g of the product from Example 3 are shaken in 20 ml of a test microbial suspension of Pseudomonas aeruginosa. After a contact time of 60 minutes, 1 ml of the test suspension is removed and the number of 25 microbes in the test mixture is determined. After expiry of this time the number of microbes has fallen from 107 to 103. Example 4: 30 1.5 g of ethyl 3-ethylamino-2-butenoate (Sigma), 1.5 g of ethyl 3-methylamino-2-butenoate (Sigma) and 35 ml of ethanol are charged to a three-necked flask and heated to 650C under a stream of argon. 0.1 g of azobisisobutyronitrile dissolved in 3 ml of ethyl 35 methyl ketone is then slowly added dropwise, with stirring. The mixture is heated to 70*C and stirred for 72 h at this temperature. After this time the reaction mixture is stirred into 0.35 1 of n-hexane, whereupon the polymeric product precipitates. After the product - 16 has been filtered off the filter residue is washed with 70 ml of n-hexane to remove any residual monomers still present. The product is then dried in vacuo for 24 hours at 50*C. 5 Example 4a: 0.05 g of the product from Example 4 are shaken in 20 ml of a test microbial suspension of Staphylococcus aureus. After a contact time of 15 minutes, 1 ml of the 10 test suspension is removed and the number of microbes in the test mixture is determined. After expiry of this time no Staphylococcus aureus microbes are now detectable. 15 Example 4b: 0.05 g of the product from Example 4 are shaken in 20 ml of a test microbial suspension of Pseudomonas aeruginosa. After a contact time of 60 minutes, 1 ml of the test suspension is removed and the number of 20 microbes in the test mixture is determined. After expiry of this time the number of microbes has fallen from 107 to 102. Example 5: 25 4 g of methyl 2-acrylamido-2-methoxyacetate (Aldrich), 5 g of methyl 2-acetamidoacrylate (Aldrich), 3 g of methyl methacrylate (Aldrich) and 65 ml of ethanol are charged to a three-necked flask and heated to 65*C under a stream of argon. 0.15 g of 30 azobisisobutyronitrile dissolved in 4 ml of ethyl methyl ketone are then slowly added dropwise, with stirring. The mixture is heated to 70*C and stirred for 72 h at this temperature. After this time the reaction mixture is stirred into 0.5 1 of n-hexane, whereupon 35 the polymeric product precipitates. After the product has been filtered off the filter residue is washed with 100 ml of n-hexane to remove any residual monomers still present. The product is then dried in vacuo for 24 hours at 50 0

C.

- 17 Example 5a: 0.05 g of the product from Example 5 are shaken in 20 ml of a test microbial suspension of Staphylococcus 5 aureus. After a contact time of 15 minutes, 1 ml of the test suspension is removed and the number of microbes in the test mixture is determined. After expiry of this time no Staphylococcus aureus microbes are now detectable. 10 Example 5b: 0.05 g of the product from Example 5 are shaken in 20 ml of a test microbial suspension of Pseudomonas aeruginosa. After a contact time of 60 minutes, 1 ml of 15 the test suspension is removed and the number of microbes in the test mixture is determined. After expiry of this time the number of microbes has fallen from 107 to 102. 20 Example 6: 4 g of methyl 2-acrylamido-2-methoxyacetate (Aldrich), 4 g of methyl 2-acetamidoacrylate (Aldrich), 2.5 g of butyl methacrylate (Aldrich) and 65 ml of ethanol are charged to a three-necked flask and heated to 65*C 25 under a stream of argon. 0.15 g of azobisisobutyronitrile dissolved in 4 ml of ethyl methyl ketone are then slowly added dropwise, with stirring. The mixture is heated to 70*C and stirred for 72 h at this temperature. After this time the reaction 30 mixture is stirred into 0.5 1 of n-hexane, whereupon the polymeric product precipitates. After the product has been filtered off the filter residue is washed with 100 ml of n-hexane to remove any residual monomers still present. The product is then dried in vacuo for 35 24 hours at 50*C. Example 6a: 0.05 g of the product from Example 6 are shaken in 20 ml of a test microbial suspension of Staphylococcus - 18 aureus. After a contact time of 15 minutes, 1 ml of the test suspension is removed and the number of microbes in the test mixture is determined. After expiry of this time the number of microbes has fallen from 107 to 10 3 . 5 Example 6b: 0.05 g of the product from Example 6 are shaken in 20 ml of ,a test microbial suspension of Pseudomonas aeruginosa. After a contact time of 60 minutes, 1 ml of 10 the test suspension is removed and the number of microbes in the test mixture is determined. After expiry of this time the number of microbes has fallen from 107 to 104. 15 In addition to the microbicidal action described above with respect to cells of Pseudomonas aeruginosa and Staphylococcus aureus, all of the specimens also exhibited microbicidal action with respect to cells of Klebsiella pneumoniae, Escherichia coli, Rhizopus 20 oryzae, Candida tropicalis and Tetrahymena pyrifomis.

Claims (20)

1. An antimicrobial polymer obtainable by copolymerizing (component I) aliphatically 5 unsaturated monomers which have been at least singly functionalized by means of a secondary amino group with (component II) another aliphatically unsaturated monomer which has been at least singly functionalized by means of a 10 secondary amino group, where component I and component II are different from one another.

2. An antimicrobial polymer as claimed in claim 1, wherein 15 the copolymerization is carried out with (component III) other aliphatically unsaturated monomers.

3. An antimicrobial polymer as claimed in one of 20 claims 1 and 2, wherein each of components I and II comprises aliphatically unsaturated monomers functionalized by means of a secondary amino group and having the 25 general formula R1NR 2 H where Ri is a branched, unbranched or 30 cyclic, saturated or unsaturated hydrocarbon radical having up to 50 carbon atoms which may have substitution by O atoms, N atoms or S atoms, and 35 R2 is a branched, unbranched or cyclic, saturated or unsaturated hydrocarbon radical having up to 25 carbon atoms, which may have - 20 substitution by 0 atoms, N atoms or S atoms.

4. An antimicrobial polymer as claimed in one of 5 claims 1 to 3, wherein there is a molar mass difference of at least 23 g/mol between the monomers of components I and II. 10

5. An antimicrobial polymer as claimed in one of claims 1 to 4, wherein the copolymerization is carried out on a 15 substrate.

6. An antimicrobial polymer as claimed in one of claims 1 to 4, wherein 20 the copolymerization is carried out as a graft polymerization of a substrate.

7. An antimicrobial polymer as claimed in claim 6, wherein 25 the substrate is activated prior to the graft polymerization by UV radiation, plasma treatment, corona treatment, flame treatment, ozonization, electrical discharge or y-radiation. 30

8. An antimicrobial polymer as claimed in claim 6, wherein the substrate is activated prior to the graft polymerization by UV radiation with a photoinitiator. 35

9. A process for preparing antimicrobial polymers by copolymerizing (component I) aliphatically unsaturated monomers which have been at least singly functionalized by means of a secondary - 21 amino group with (component II) another aliphatically unsaturated monomer which has been at least singly functionalized by means of a secondary amino group, where component I and 5 component II are different from one another.

10. The process as claimed in claim 9, wherein the copolymerization is carried out with 10 (component III) other aliphatically unsaturated monomers.

11. The process as claimed in one of claims 9 and 10, wherein 15 each of components I and II comprises aliphatically unsaturated monomers functionalized by means of a secondary amino group and having the general formula 20 RiNR 2 H where R1 is a branched, unbranched or cyclic, saturated or unsaturated hydrocarbon radical having up to 25 50 carbon atoms which may have substitution by 0 atoms, N atoms or S atoms, and R2 is a branched, unbranched or cyclic, saturated or unsaturated 30 hydrocarbon radical having up to 25 carbon atoms, which may have substitution by 0 atoms, N atoms or S atoms. 35

12. The process as claimed in one of claims 9 to 11, wherein there is a molar mass difference of at least 23 g/mol between the monomers of components I and II. - 22

13. The process as claimed in one of claims 9 to 12, wherein the copolymerization is carried out on a substrate. 5

14. The process as claimed in one of claims 9 to 12, wherein the copolymerization is carried out as a graft polymerization of a substrate. 10

15. The process as claimed in claim 14, wherein the substrate is activated prior to the graft polymerization by UV radiation, plasma treatment, 15 Corona treatment, flame treatment, ozonization, electrical discharge or y-radiation.

16. The process as claimed in claim 14, wherein 20 the substrate is activated prior to the graft polymerization by UV radiation with a photoinitiator.

17. The use of the antimicrobial polymers as claimed 25 in one of claims 1 to 8 for producing products with an antimicrobial coating made from the polymer.

18. The use of the antimicrobial polymers as claimed 30 in one of claims 1 to 8 for producing items in medical technology with an antimicrobial coating made from the polymer.

19. The use of antimicrobial polymers as claimed in 35 one of claims 1 to 8 for producing hygiene items with an antimicrobial coating made from the polymer., - 23

20. The use of the antimicrobial polymers as claimed in one of claims 1 to 8 in surface coatings, in protective paints or in other coatings.