Title of Invention

A PROCESS OF MAKING AQUEOUS ANTIMICROBIAL HYGIENIC COATING COMPOSITION

Abstract

A process of making an Aqueous Antimicrobial Hygienic Coating Composition, to confer on the dry film sustained broad spectrum antimicrobial properties; comprising of the following steps : a) adding slowly Dispersing agent (0.5-2%), Emulsifier (0.01-5%), Freeze-thaw stabilizer (0-5%), Thickner (1-3%) in water at a slow speed in a twin shaft disperser; b) adding slowly powders such as Pigments (5-50%), Biocidal additives (0.01-20%) in the mixture of step (a) and grinding at high speed (Peripheral speed of 5-18 m/sec) for 1 1/2 - 2 hours; c) cooling the resultant slurry to less than 55°C; d) adding under slow speed Biocidal additives (0.01-20%), Adjuvants (0.01-20%), Binder (10-50%), and remaining water in the resultant slurry of step (b); e) adjusting the Viscosity at 6000-10000 c.p.s.

Full Text

FORM2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See Section 10, rule 13) A PROCESS OF MAKING AQUEOUS ANTIMICROBIAL HYGIENIC COATING COMPOSITION; KANSAI NEROLAC PAINTS LTD. OF GANPATRAO KADAM MARG, LOWER PAREL, MUMBAI 400 013, MAHARASHTRA, India, INDIAN Company. The following specification particularly describes the nature of the invention and the manner in which it is to be performed:- GRANTED 16-8-2007 ORIGINAL A PROCESS OF MAKING AQUEOUS ANTIMICROBIAL HYGIENIC COATING COMPOSITION The present invention relates to an Aqueous Antimicrobial Hygieruc Coating Composition. More particularly the present invention relates to a coating composition which displays dry film (and in-can) antibacterial & antifungal action. The unique paint composition including the biocides and other additives in the coating formulation confers sustained activity against tenacious bacteria such as, Pseudomonas species; and capsulated bacteria such as Klebsiella; and also against airborne surface biodeteriorating fungi The synergistic biocidal blend in the coating composition includes individually or in combination components selected from the group consisting of n-butyl-1,2-benzisothiazolin-3-one, N-trichloromethylthiophthalimide, 2-n-octyl-4-isothiazolin-3-one/ zinc pyrithione, zinc zeolite, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothicizolin-3-one, diAio-2, 2-bis (benzmethylamide), methyl benzimidazol-2-yl carbamate, zinc dimethyldithiocarbamate, iodo propynyl butyl carbamate and a silver component deposited on a carrier and a salt of barium such as sulfate, chromate, metaborate monohydrate and / or chloride. HELD OF THE INVENTION: The present invention relates to a dry film antibacterial and antifungal coating that shows broad spectrum and sustained antibacterial activity. The resultant composite coating shows excellent retention of antimicrobial activity even after repeated washing with water, detergent and disinfectants. The cured coating film also shows biocidal activity after repeated cold-hot cycles (-10°C to +35°C). BACKGROUND OF INVENTION & PRIOR STATE OF ART. As a technology for keeping surfaces free of microbes, a coating containing antimicrobial compounds (s) can be used. Antimicrobial coatings can be used on the surfaces of a variety of medical, domestic and commercial rooms where control of microbial growth is of particular concern. A variety of such antimicrobial coatings have been described and are available in the market. However, from the various products tested and literature studied it was found that the coatings were not effective against some of the bacteria used for tests, Pseudomonas sp. & Klebsiella sp. in particular. Pseudomonas is a pathogen and a very resiUent organism tolerant to various antimicrobial agents. Klebsiella is a capsulated opportunistic pathogenic bacterium which shows resistance / tolerance to common disinfectants owing to its polysaccharide capsule. Other microbe of concern is MRSA. All these organisms pose a problem in the increased incidences of nosocomial infections. It was also observed that the available coatings lost the antibacterial activity on leaching or washing. Silver based aqueous coating compositions have been described, these show^ antibacterial activity but have a limited activity against fungi, whereas 2-n-ociyl- 4-isothiazolin-3-one is a superior fungicide with relatively lower activiiy against Gram-negative bacteria. Similar shortcomings were observed with zinc based coating formulations. Also, n-butyl-l,2-benzisothiazolin-3-one, N-trichloromethylthiophthalimide, 2-n-octyl-4-isothiazolin-3-one, zinc pyrithione, zinc zeolite, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, dithio-2, 2-bis (benzmethylamide), methyl benzimidazol-2-yl carbamate, zinc dimethyldithiocarbamate, iodo propynyl butyl carbamate containing formulations showed varying degrees of surface and in-can antifungal & antibacterial properties, but the coating formulations either did not possess a broad spectrum activity (especially against Pseudomonas sp. & Klebsiella sp.) or lost their microbicidal activity on leaching. Barium metaborate monohydrate has been used in coating formulations for antifungal and antialgal activity. It has also been used to provide in - can bactericidal protection. Barium metaborate monohydrate based coating formulations showed good activity against Pseudomonas and moderate antifungal activity, however it showed meagre or nil activity against Gram positive bacteria such as Staphylococcus. Moreover the dry film anti Pseudomonas activity was lost readily on leaching, therefore such a coating would not withstand cleaning and disinfection regimes. It is therefore an object of the present invention to provide a coating that possesses broad spectrum antibacterial and anti fungal activity. The coating has been formulated in such a fashion that the antimicrobial activity remains intact even after the coated surface is subjected to detergent washings and surface treatment using common disinfectants thus ensuring a long lasting sustained antimicrobial activity. GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENTS : The present invention utilizes the antimicrobial activity of a combination of Barium metaborate monohydrate, a silver component and other biocides (from the ones mentioned above) to achieve dry film antimicrobial properties. Various antimicrobial paint additives were tested at different use levels in the formulation. Among the agents tested only Barium metaborate monohydrate has shown significant activity against Pseudomonas sp. Barium metaborate monohydrate is reported to have good antibacterial activity in the wet state. It can also degrade microbial enzymes in the wet state. It has not been used for dry film antibacterial activity. Experimental studies in our laboratory revealed that Barium metaborate monohydrate is active against Pseudomonas sp. and fungi. The present invention utilizes this property of Barium metaborate monohydrate to impart anti Pseudomonas activity to a dried paint film. Barium metaborate monohydrate has however not shown significant activity against other bacteria. One other drawback observed of Barium metaborate monohydrate is its solubility in water, which resulted in reduced antibacterial activity of the cured coated surface after water leaching. Experiments were conducted to improve the leach resistance of Barium metaborate monohydrate and to supplement its antibacterial spectrum.The ideal dosage of Barium metaborate monohydrate and /or Barium chloride along with the specific types and dosages of binder, a polymer such as acrylic, vinyl, sfyrene, poly urethane have been worked out. The other antimicrobial additives used in this invention are a silver component and individually or in combination components from the group comprising n-bu1yl-l, 2-benzisothiazolin-3-one, N-trichloromethylthiophthalimide, 2-n-octyl-4-isothiazolin-3-one, zinc pyrithione, zinc zeolite, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, dithio-2, 2-bis (benzmethylamide), methyl benzimidazol-2-yl carbamate, zinc dimethyldithiocarbamate, iodo propynyl butyl carbamate. The silver component is a commercially available AgCl coated TiO2. This additive has been found to give antibacterial and some amount of antifungal activity. It is found effective against Gram positive and some Gram negative orgarusms. The other biocidal blend has been found to impart excellent antifungal and moderate antibacterial properties to the paint film. The leach resistance of the coating has been improved by the ideal pigment / binder balance (PVC) and the use of a Silane additive. Examples : The following examples (A...F) constitute some paint formulations based on the above experimental work. This is not an exhaustive hst of the compositions tested. Comparative compositions G and H are examples of the prior state of art coating formulations. Manufacturing Process: Example 1 To make the coating composition, twin shaft disperser is used. Take a clean container. Add about 70% of the water. Add under slow speed additives like surfactants (1), emulsifier (5), 65% of the glycolic freeze-thaw stabilizer (18), 50% of the defoamer (2), thickner (22), adjunct (16,17), mix for 15 minutes. Add powders (3, 4, 6, 7) and run at high speed (peripheral speed of 5-18 m/sec) for 1 1/2 to 2 hours. Add water intermittently if required. Check finish with appropriate addition of binder and water in small sample of slurry and then applying by brush. Cool to below 55°C. add remaining ingredients under slow speed such as some biocides (8 - 15), binder (21), remaining defoamer (2), additives (18, 20), thickner (19) and remaining water. Tint with appropriate colourant, if particular shade is required. Physical Properties of the coating composition: 1 Consistency - Smooth and uniform - CI No. 7.4 IS:101 -1964 2 Drying Time- - IS:101 (Part 3/Sec 1) -1986 a) Surface dry - 15 minutes b) Hard dry - 4 hours 3 Finish - Smooth and matt to semi-glossy - IS:101 (Part 3/Sec 4) -1987 4 Alkali Resistance - Passes test - IS:5411 (Part 1) 1974- Appendix C Determination Of Resistance To Alkali AppKcation Method: The paint sample is thinned with 30% of water, by volume and apphed by brushing. The second coat is applied after overnight drying. Outline of Microbial Testing Methods : Dry Film Bactericidal Testing 1. Two coats of the coating composition are applied on an inert test panel. 2. The paint film is allowed to cure for seven days. 3. A set of the coated panel is subjected to artificial weathering viz. Leaching with water/detergent scrub/ tieatment with disinfectants/ hot-cold cycles etc. 4. The unweathered & artificially weathered coated test panels are sterilized by UV irradiation. 5. Known type & quantity of a 24-hour old bacterial culture suspension is placed on the unweathered and artificially weathered coating. 6. The test set is maintained at room temperature under humid conditions. 7. After 24 hours the number of surviving test bacteria is evaluated. Dry Film Fungicidal Testing: 1. Two coats of the coating composition are applied on an inert test panel. 2. The paint film is allowed to cure for seven days. 3. A set of the coated panel is subjected to artificial weathering viz. Leaching with water/detergent scrub/ tieatment with disinfectants/ hot-cold cycles etc. 4. The unweathered & artificially weathered coated test panel are sterilized by UV irradiation. 5. The imweathered and artificially weathered paint film is challenged with a mixture of fungal spore suspension including A.niger, A.fumigatus, Cladosporium sp., Penicilhum sp. Paecilomyces variotii, Fusarium sp. 6. Incubated under humid conditions. 7. Observations are made using stereo microscope at specific intervals (up to 8 weeks), to check for fungal growth on the coating surface. In-Can Microbial Testing: 1. 100 gm aliquots of the test paint formulation are taken. 2. The test paint is challenged with a bacterial suspension comprising of a mixture of paint deteriorating bacteria and yeast. 3. Such Microbial challenge is carried out weekly for 3 weeks. 4. Surviving microbes are enumerated at weekly intervals for 4 weeks. This is an embodiment of the invention and many other modifications may be considered within the ambit and spirit of this invention, since many variations and changes in detail may be made to the above described embodiments. Test Results Dry Film Bactericidal Testing 1. Un-weathered Coating 3. Scrub Resistance Test (Sheen Wet Abrasion Scrub Tester^ 1% detergent solution) 4. Hot - Cold cycles (ten cycles of 22 hours at -10°C & 2 hours at 35°C) Key : Bacterial growth density + ++ +++ ++++ +++++ No bacteria detected 80 - 120 colony forming luiits/ ml 800 - 1200 colony forming units/ ml 80000 - 120000 colony forming units/ml 1000000 colony forming units/ ml Conclusion: 1. The coating composition of the present invention illustrated in examples A to F shows dry film bactericidal action under un-weathered and artificially weathered conditions, whereas the prior state of art coating compositions as illustrated in examples G & H do not show dry film bactericidal action. 2. The present coating composition illustrated in A to F shows in test reports 99% reduction in bacterial growth in comparison to the prior state of art compositions as illustrated in G & H, after artificial weathering conditions. Dry Film Fungicidal Testing Against mixed fungi including A.niger, A.fumigatus, Cladosporium sp., Penicillium sp. Paecilomyces variotii, Fusarium sp. Observations after 8 weeks of incubation: Key: Artificial Weathering conditions L Un-weathered M 24 Hours water leaching N 2500 scrubs on 'Sheen' Wet scrub tester with 1% detergent solution O Hot - Cold cycles (ten cycles of 22 hours at -10°C & 2 hours at 35°C) Fungal Growth Rating 1 Traces of fungal growth 2 2 - 10% of coated surface covered with fungal growth 3 11 - 30% of coated surface covered with fungal growth 4 31 - 70% of coated surface covered with fungal growth Conclusion The present coating composition as illustrated in examples A to F shows fungal resistance even after detergent scrubbing, whereas the prior state of art compositions as illustrated in examples G & H are found to support fungal growth on their surfaces after the scrub resistance test. WE CLAIM: 1. A process of making an Aqueous Antimicrobial Hygienic Coating Composition, to confer on the dry film sustained broad spectrum antimicrobial properties; comprising of the following steps : a) adding slowly Dispersing agent (0.5-2%), Emulsifier (0.01-5%), Freeze-thaw stabilizer (0-5%), Thickner (1-3%) in water at a slow speed in a twin shaft disperser; b) adding slowly powders such as Pigments (5-50%), Biocidal additives (0.01-20%) in the mixture of step (a) and grinding at high speed (Peripheral speed of 5-18 m/sec) for 1 1/2 - 2 hours; c) cooling the resultant slurry to less than 55°C; d) adding under slow speed Biocidal additives (0.01-20%), Adjuvants (0.01-20%), Binder (10-50%), and remaining water in the resultant slurry of step (b); e) adjusting the Viscosity at 6000-10000 c.p.s. 2. A process of making an Aqueous Antimicrobial Hygienic Coating Composition as claimed in claim 1, wherein the biocidal additives are selected individually and / or in combination from the group consisting of n-butyl-1, 2-benzisothiazolin-3-one, N- trichloromethylthiophthalimide, 2-n-octyl-4-isothiazolin-3-one, zinc pyrithione, zinc zeolite, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, dithio- 2, 2-bis (benzmethylamide), methyl benzimidazol-2-yl carbamate, zinc dimethyldithiocarbamate, iodo propynyl butyl carbamate and a silver component deposited on a carrier and a salt of barium such as sulfate, chromate, metaborate monohydrate and / or chloride. 3. A process of making an Aqueous Antimicrobial Hygienic Coating Composition as claimed in claim 1, wherein the adjuvants are selected individually and / or in combination from the group of organosilane additives such as Beta-(3,4-Epoxycyclohexyl) ethyltrimethoxy Silane, Gama-Glycidoxypropyltrimethoxy Silane, 3-glycidoxypropylmethyldiethoxy-silane. 4. A process of making an Aqueous Antimicrobial Hygienic Coating Composition as claimed in claim 1, wherein said binder is a suitable water borne polymer such as acrylic, vinyl, styrene, polyurethane. Dated this 11TH day of March, 2004. HIRAL CHANDRAKANT JOSHI AGENT FOR GOODLASS NEROLAC PAINTS LTD.

Documents:

322-mum-2004-cancelled page(16-08-2007).pdf

322-mum-2004-claim(granted)-(16-08-2007).pdf

322-mum-2004-correspondence 1(11-08-2006).pdf

322-mum-2004-correspondence 1(ipo)-(11-01-2007).pdf

322-mum-2004-correspondence 2(16-08-2004).pdf

322-mum-2004-correspondence 2(ipo)-(24-04-2007).pdf

322-mum-2004-form 1(04-04-2007).pdf

322-mum-2004-form 1(16-03-2004).pdf

322-mum-2004-form 13(11-08-2006).pdf

322-mum-2004-form 2(granted)-(16-08-2007).pdf

322-mum-2004-form 3(04-04-2007).pdf

322-mum-2004-form 3(16-03-2004).pdf

322-mum-2004-other(23-01-2007).pdf

322-mum-2004-power of attorney(16-03-2004).pdf