Isothiazolinone Biocides Enhanced By Zinc Ions

Abstract

The present invention relates to an antimicrobial composition comprising an isothiazolinone, such as 1,2-benzisothiazolin-3-one, and a zinc compound selected from zinc salts, zinc oxides, zinc hydroxides or combinations thereof. Useful zinc salts include for example, oxides, sulfates, chlorides, and combinations thereof. In use, the zinc from the zinc compound enhances the antimicrobial activity to the isothiazolin-containing composition. This enhancement permits achieving the desired antimicrobial activity at a lower usage rate than is achieved using the isothiazolinone in the absence of the zinc compound. The antimicrobial composition can also contain co-biocides, such as pyrithiones, including zinc pyrithione or copper pyrithione.

What is claimed is: 
     
         1 . An antimicrobial composition comprising (a) at least one isothiazolin-3-one and (b) at least one zinc compound selected from the group consisting of zinc salts, zinc oxides, zinc hydroxides, and combinations thereof, wherein said isothiazolin-3-one is present in an amount of from 1 to 500 ppm, the zinc compound is present in an amount of from 5 to 200,000 ppm, and the weight ratio of the isothiazolin-3-one to the zinc compound is from 1:2000 to 100:1. 
     
     
         2 . The composition of  claim 1  wherein component (a) is present in an amount of from 1 to 500 ppm, component (b) is present in an amount of from 5 to 200,000 ppm, and the weight ratio is from 1:100 to 100:1. 
     
     
         3 . The composition of  claim 1  wherein component (a) is present in an amount of from 5 to 500 ppm, and component (b) is present in an amount of from 5 to 500 ppm. 
     
     
         4 . The antimicrobial composition of  claim 1  wherein said isothiazolin-3-one is selected from the group consisting of 1,2-benzisothiazolin-3-one, N-(n-butyl)-1,2-benzisothiazolin-3-one, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, mixtures of 5-chloro-2-methyl-4-isothiazolin-3-one (CIMIT) and 2-methyl-4-isothiazolin-3-one, and also dithio-2,2′-bis(benzmethylamide), and combinations thereof. 
     
     
         5 . The antimicrobial composition of  claim 1  wherein said zinc salt is selected from the group consisting of zinc chloride, zinc sulfide, zinc carbonate, basic zinc carbonate, and combinations thereof. 
     
     
         6 . The antimicrobial composition of  claim 1  wherein said zinc compound is zinc chloride. 
     
     
         7 . The antimicrobial composition of  claim 1  which further comprises a co-biocide selected from the group consisting of pyrithione salts, pyrithione acids, and combinations thereof, and wherein said co-biocide is present in said composition in an amount of from about 0.001 to about 1% w/w based on the total weight of said composition. 
     
     
         8 . An antimicrobial composition concentrate, which upon dilution with water provides the amounts of components (a) and (b) as specified in  claim 1 , said concentrate comprising isothiazolin-3-one in an amount of between 1 and 95% w/w. 
     
     
         9 . The antimicrobial composition concentrate of  claim 8  which further comprises a co-biocide selected from the group consisting of pyrithione salts, pyrithione acids, and combinations thereof, and wherein said co-biocide is present in said composition in an amount of from about 1 to about 50% w/w based on the total weight of said composition. 
     
     
         10 . A composition comprising a polymer emulsion, said composition additionally comprising a wet state preservative comprising a combination of (a) at least one isothiazolin-3-one and (b) at least one zinc compound selected from the group consisting of zinc salts, zinc oxides, zinc hydroxides, and combinations thereof, wherein said combination is present in said composition in a total amount of between about 10 ppm and about 400 ppm, and wherein the molar ratio of component (a) to component (b) is between about 4:1 and about 1:2. 
     
     
         11 . The composition of  claim 10  wherein said polymer emulsion comprises a polymer selected from the group consisting of acrylic and substituted (meth)acrylates, styrene/butadiene, ethylene vinyl acetate, polyvinyl acetate, styrene/butadiene/N-methylol acrylamide, nitrile and copolymers thereof. 
     
     
         12 . The antimicrobial composition of  claim 10  wherein said zinc salt is selected from the group consisting of zinc chloride, zinc sulfide, zinc carbonate, basic zinc carbonate, and combinations thereof. 
     
     
         13 . The antimicrobial composition of  claim 12  wherein said zinc salt is zinc chloride. 
     
     
         14 . The composition of  claim 10  wherein said isothiazolin-3-one is selected from the group consisting of: 1,2-benzisothiazolin-3-one, N-(n-butyl)-1,2-benzisothiazolin-3-one, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, mixtures of 5-chloro-2-methyl-4-isothiazolin-3-one (CIMIT) and 2-methyl-4-isothiazolin-3-one, and also dithio-2,2′-bis(benzmethylamide), and combinations thereof. 
     
     
         15 . The composition of  claim 10  which further comprises a co-biocide selected from the group consisting of pyrithione salts, pyrithione acids, and combinations thereof, and wherein said co-biocide is present in said composition in an amount of from about 0.001 to about 1.0% w/w based on the total weight of said composition. 
     
     
         16 . The composition of  claim 15  wherein said pyrithione salts are selected from the group consisting of copper pyrithione, zinc pyrithione, sodium pyrithione, and combinations thereof. 
     
     
         17 . A coating composition selected from the group consisting of paints, adhesives, sealants, caulks, mineral and pigment slurries, printing inks, agricultural pesticide formulations, household coating products, personal care products, metal working fluids, and combinations thereof, wherein said coating composition contains a polymer emulsion as a liquid base medium, and a wet state preservative comprising a combination of (a) at least one isothiazolin-3-one and (b) at least one zinc compound selected from the group consisting of zinc salts, zinc oxides, zinc hydroxides, and combinations thereof, wherein said combination is present in said composition in a total amount of between about 10 ppm and about 400 ppm, and wherein the molar ratio of component (a) to component (b) is between about 4:1 and about 1:2. 
     
     
         18 . The coating composition of  claim 17  wherein said liquid base medium is selected from the group consisting of acrylic and substituted (meth)acrylates, styrene/butadiene, ethylene vinyl acetate, polyvinyl acetate, styrene/butadiene/N-methylol acrylamide, nitrile and copolymers thereof.