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US 6,471,885 B2Granted
Leather coating composition
AssigneeRohm and Haas Company
InventorsJin-chih Chiang, Shang-Jaw Chiou, Frederick James Schindler
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Abstract
An aqueous leather coating composition containing a multi-stage emulsion polymer having a stage of Tg<10° C. which contains a copolymerized carboxylic acid and which has been contacted with a divalent metal oxide, hydroxide, or carbonate and a polymer stage of Tg>20° C. which has been prepared in the presence of 1% to 15% by weight based on the weight of that stage of chain transfer agent is provided. Also, provided is a method for coating leather with the composition of this invention.
Claims10
An aqueous leather coating composition comprising a multi-stage aqueous emulsion-polymer comprising
- (i) a predominantly acrylic first stage polymer comprising at least one copolymerized monoethylenically-unsaturated nonionic monomer and from 0.5% to 10% of a copolymerized monoethylenically-unsaturated carboxylic acid monomer, based on the weight of said first stage polymer, said first stage polymer being substantially free from copolymerized multiethylenically-unsaturated monomer, said first stage polymer having Tg less than 10° C., said first stage polymer having been contacted with a transition metal oxide, hydroxide, or carbonate at a pH of less than 9 in an amount greater than 0.1 equivalent of transition metal per equivalent of said copolymerized carboxylic acid monomer in said first stage polymer;
- and
- (ii) a second stage polymer comprising at least one copolymerized monoethylenically-unsaturated nonionic monomer and from 0% to 10% of a copolymerized monoethylenically-unsaturated carboxylic acid monomer, based on the weight of said second stage polymer wherein said second stage polymer is formed in the presence of from 1% to 15% by weight based on the weight of said second stage polymer of chain transfer agent, provided that said second stage copolymerized carboxylic acid monomer is less than 25%, by weight, of the total copolymerized carboxylic acid monomer in said multi-stage emulsion polymer, said second stage polymer being substantially free from copolymerized multiethylenically-unsaturated monomer, said second stage polymer having Tg greater than 20° C.;
- and said second stage polymer being from 1% to 50% of the weight of said first stage polymer, based on dry polymer weights.
1 more element
A method for coating leather comprising
- (a) forming an aqueous leather coating composition comprising a multi-stage aqueous emulsion-polymer formed by a method comprising
- (i) forming a predominantly acrylic first stage polymer comprising at least one copolymerized monoethylenically-unsaturated nonionic monomer and from 0.5% to 10% of a copolymerized monoethylenically-unsaturated carboxylic acid monomer, based on the weight of said first stage polymer, said first stage polymer being substantially free from copolymerized multiethylenically-unsaturated monomer;
- and said first stage polymer having a Tg less than 10° C.;
- (ii) contacting said first stage polymer with a transition metal oxide, hydroxide, or carbonate at a pH of less than 9 in an amount greater than 0.1 equivalent of transition metal per equivalent of said copolymerized carboxylic acid monomer in said first stage polymer;
- and
- (iii) forming a second stage polymer comprising at least one copolymerized monoethylenically-unsaturated nonionic monomer and from 0 to 10% of a copolymerized monoethylenically-unsaturated carboxylic acid monomer, based on the weight of said second stage polymer, wherein said second stage polymer is formed in the presence of from 1% to 15% by weight based on the weight of said second stage polymer of chain transfer agent, provided that said second stage copolymerized carboxylic acid monomer is less than 25%, by weight, of the total copolymerized carboxylic acid monomer in said multi-stage emulsion polymer, said second stage polymer being substantially free from copolymerized multiethylenically-unsaturated monomer, said second stage polymer having a Tg greater than 20° C., and said second stage polymer being from 1% to 50% of the weight of said first stage polymer, based on dry polymer weights,
- (b) applying said coating composition to leather;
- and
- (c) drying said coating composition.
6 more elements
Dependencies are inferred from the claim text.