Coating processes – Medical or dental purpose product; parts; subcombinations;... – Flexible web – sheet – film – or filament base
Reexamination Certificate
2000-03-17
2001-11-13
Pianalto, Bernard (Department: 1762)
Coating processes
Medical or dental purpose product; parts; subcombinations;...
Flexible web, sheet, film, or filament base
C427S223000, C427S299000, C427S322000, C427S325000, C427S327000, C427S385500, C427S388100, C427S393000, C427S393500, C427S399000, C427S421100, C427S430100, C427S440000, C427S443200, C427S488000, C427S496000, C427S498000, C427S512000, C427S535000, C427S551000, C427S553000, C427S558000, C427S559000, C427S569000, C427S580000, C427S595000
Reexamination Certificate
active
06316044
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for the preparation of antimicrobial polymers by polymerization of tert-butylaminoethyl methacrylate, and the use of the antimicrobial polymers. More particularly, the invention relates to a process for the preparation of antimicrobial polymers by graft polymerization of tert-butylaminoethyl methacrylate on a substrate, and the use of the antimicrobial polymers.
2. Description of the Background
The colonization and spread of bacteria on surfaces of pipelines, containers or packaging is highly undesirable. Layers of slime often form, which allow the microbe populations to rise to extreme levels, lastingly impairing the quality of water, drinks and foodstuffs, and can even lead to decay of the goods and damage to the health of consumers.
Bacteria are to be kept away from all areas of life where hygiene is of importance. Since textiles directly contact the body, and, in particular the genital area, and are used for the care of the sick and elderly, textiles should be freed of bacteria. Bacteria should also be kept away from the surfaces of furniture and equipment in nursing wards, in particular in the intensive care and infant care sector, in hospitals, especially in rooms for medical operations, and in isolation wards for critical cases of infection, as well as in toilets.
Equipment, and surfaces of furniture and textiles are currently treated to ward against bacteria as required or also preventively with chemicals or solutions and mixtures thereof which act as disinfectants, such having a more or less broad and powerful antimicrobial action. Such chemical compositions have a nonspecific action, are often themselves toxic or irritating, or form degradation products which are unacceptable to health. Intolerances are often also found in appropriately sensitized persons. Another procedure which is used to inhibit the spread of bacteria on surfaces is to incorporate antimicrobially active substances into a matrix.
Tert-butylaminoethyl methacrylate is a commercially available monomer of methacrylate chemistry and is employed in particular as a hydrophilic monomer in copolymerizations. Thus, EP 0 290 676 describes the use of various polyacrylates and polymethacrylates as a matrix for immobilization of bactericidal quaternary ammonium compounds.
U.S. Pat. No. 3,592,805 discloses the preparation of systemic fungicides in which per halogenated acetone derivatives are reacted with methacrylate esters, such as, for example, tert-butylaminoethyl methacrylate.
U.S. Pat. No. 4,515,910 describes the use of polymers of hydrogen fluoride salts of aminomethacrylates in dental medicine. The hydrogen fluoride bonded in the polymers emerges slowly from the polymer matrix and is said to be effective against caries.
In another technical field, U.S. Pat. No. 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 methacrylate promoting slow erosion of the polymer and in this way liberating the highly toxic tributyltin methacrylate as an antimicrobially active compound.
In these applications, the copolymer prepared with aminomethacrylates is only a matrix or carrier substance for added microbicidal active compounds, which can diffuse or migrate out of the carrier. Polymers of this type lose their action at a faster or slower rate when the necessary “minimum inhibitory concentration” (MIC) is no longer achieved on the surface.
EP 0 204 312 describes a process for the preparation of antimicrobially treated acrylonitrile fibers. The antimicrobial action is based on a protonated amine as a comonomer unit, dimethylaminoethyl methacrylate and tertbutylaminoethyl methacrylate, inter alia, being used as protonated species. However, the antimicrobial action of protonated surfaces is severely reduced after loss of the H(+) ions. A need continues to exist for an effective method of providing surfaces of objects with antimicrobial properties.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide materials which have antimicrobial properties, which contain no active compounds which can be washed out, and in which the antimicrobial action is pH-independent.
Another object of the present invention is to provide surfaces of objects and apparatus with a permanently microbicidal polymeric coating which is not attacked by solvents and physical stress and which shows no migration, and by which it is not necessary to employ additional biocidally active compounds.
Briefly, these objects and other objects of the present invention as hereinafter will become more readily apparent can be attained by a method of imparting antimicrobial activity to the surface(s) of an apparatus or article, which comprises polymerizing tert-butylaminoethyl methacrylate in the presence of the apparatus or article by which adhesion of the polymer to said surface(s) is achieved. In a preferred embodiment of the invention the tert-butylaminoethyl methacrylate monomer is graft polymerized onto the surface.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The antimicrobial polymers of the invention can be obtained by grafting polymerizing tert-butylaminoethyl methacrylate on a surface of an article or apparatus.
Suitable substrate materials include, above all, all polymeric plastics, such as, for example, polyurethanes, polyamides, polyesters, polyethers, polyether-block amides, polystyrene, polyvinyl chloride, polycarbonates, polyorganosiloxanes, polyolefins, polysulfones, polyisoprene, polychloroprene, polytetrafluoroethylene (PTFE), corresponding copolymers and blends, as well as natural and synthetic rubbers, with or without radiation-sensitive groups. The process of the invention can also be applied on the surfaces of metal, glass or wooden bodies which are painted or are otherwise coated with plastic.
The surfaces of the substrates can be activated by a number of methods before the grafting polymerization. They are expediently freed from oils, greases or other impurities beforehand in a known manner by means of a solvent.
The standard polymers can be activated by UV radiation. A suitable source of radiation is, for example, a UV-Excimer apparatus HERAEUS Noblelight, Hanau, Germany. However, mercury vapor lamps are also suitable for activation of the substrate if they emit considerable proportions of radiation in the ranges mentioned. The exposure time generally ranges from 0.1 second to 20 minutes, preferably 1 second to 10 minutes.
The activation of the standard polymers with UV radiation can furthermore be carried out with an additional photosensitizer. Suitable such photosensitizers include, for example, benzophenone, as such are applied to the surface of the substrate and irradiated. In this context, irradiation can be conducted with a mercury vapor lamp using exposure times of 0.1 second to 20 minutes, preferably 1 second to 10 minutes.
According to the invention, the activation can also be achieved by a high frequency or microwave plasma (Hexagon, Technics Plasma, 85551 Kirchheim, Germany) in air or a nitrogen or argon atmosphere. The exposure times generally range from 30 seconds to 30 minutes, preferably 2 to 10 minutes.
The energy output of laboratory apparatus is between 100 and 500 W, preferably between 200 and 300 W.
Corona apparatus (SOFTAL, Hamburg, Germany) can furthermore be used for the activation. In this case, the exposure times are, as a rule, 1 to 10 minutes, preferably 1 to 60 seconds.
Activation by electron beams or y-rays, for example, from a cobalt-60 source) and ozonization allow short exposure times which are generally range from 0.1 to 60 seconds.
The flaming of surfaces likewise leads to activation of the surfaces. Suitable apparatus, in particular those having a barrier flame front, can be constructed in a simple manner or obtained, for example, from ARCOTEC, 71297 M{umlaut over (n)}sheim, Germany. The apparatus can employ hyd
Anders Christine
Hill Frank
Ottersbach Peter
Degussa-Huels Aktiengesellschaft
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Pianalto Bernard
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