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US 4,130,528 AGranted
Carboxylated neoprene latex containing alkali-pretreated zinc oxide or hydroxide
AssigneeE. I. Du Pont de Nemours and Company
InventorMark C. Chen
Life of this patent
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Abstract
Neoprene compositions containing a latex of a copolymer of chloroprene with an .alpha.,.beta.-ethylenically unsaturated carboxylic acid, such as methacrylic or acrylic acid, the polymerization being conducted in the presence of polyvinyl alcohol, and zinc oxide or zinc hydroxide which has been previously contacted with an alkali metal hydroxide are particularly well suited for use in contact adhesives.
Claims10
A neoprene composition comprising as its essential components:
- (1) a latex obtained by polymerizing in an emulsion substantially free of carboxylic soaps a mixture of chloroprene with a carboxylic acid having the formula ##STR2## where R is hydrogen, an alkyl radical containing 1-4 carbon atoms, or a carboxymethyl radical, the proportion of said acid being about 0.4-10 mole percent of the total monomer content, in the presence of
- (a) about 3-10 parts of polyvinyl alcohol and
- (b) about 0.3-2 parts of a chain transfer agent selected from dialkyl xanthogen disulfides and alkyl mercaptans,
- both (a) and (b) being expressed in parts by weight based on 100 parts of total monomers, the polymer in the latex containing 10-95% gel, polyvinyl alcohol not being completely recoverable by extraction of the polymer with water;
- and
- (2) about 2-10 parts of a zinc compound selected from zinc oxide and zinc hydroxide based on the copolymer content of the latex, and zinc compound having been previously contacted with an aqueous solution of an alkali metal hydroxide selected from NaOH, KOH, and LiOH, the respective proportions of these ingredients being about 0.5-10 moles of zinc compound per mole of alkali metal hydroxide.
3 more elements
A contact adhesive composition comprising as its essential components:
- (1) a latex obtained by polymerizing in an emulsion substantially free of carboxylic soaps a mixture of chloroprene with a carboxylic acid having the formula ##STR3## where R is hydrogen, an alkyl radical containing 1-4 carbon atoms, or a carboxymethyl radical, the proportion of said acid being about 0.4-10 mole percent of the total monomer content, in the presence of
- (a) about 3-10 parts of polyvinyl alcohol and
- (b) about 0.3-2 parts of a chain transfer agent selected from dialkyl xanthogen disulfides and alkyl mercaptans,
- both (a) and (b) being expressed in parts by weight based on 100 parts of total monomers, the polymer in the latex containing 10-95% gel, polyvinyl alcohol not being completely recoverable by extraction of the polymer with water;
- and
- (2) about 2-10 parts of a zinc compound selected from zinc oxide and zinc hydroxide based on the copolymer content of the latex, and zinc compound having been previously contacted with an aqueous solution of an alkali metal hydroxide selected from NaOH, KOH, and LiOH, the respective proportions of these ingredients being about 0.5-10 moles of zinc compound per mole of alkali metal hydroxide.
3 more elements
Dependencies are inferred from the claim text.