2,5-Dimercapto-1,3,4-thiadiazole as a cross-linker for saturated, halogen-containing polymers
AssigneeHercules Incorporated
InventorJohn R. Richwine
Life of this patent
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Abstract
It has been found that saturated, halogen-containing polymers can be cross-linked to yield stable vulcanizates using 2,5-dimercapto-1,3,4-thiadiazole in the presence of certain basic materials in normal vulcanization procedures.
Claims26
The process of cross-linking a halogen-containing polymer which contains at least about 2% by weight of halogen and less than 0.1 mole % ethylenic unsaturation, which comprises heating said polymer in the presence of 2,5-dimercapto-1,3,4-thiadiazole and a basic material selected from (1) amines having a boiling point above about 110.degree. C. and a pK value below about 4.5;
- (2) salts of amines having pK values below about 4.5 with acids having pK values above about 2.0;
- (3) quaternary ammonium hydroxides and their salts with acids having pK values above about 2.0;
- (4) diphenyl- and ditolylguanidines;
- and (5) the condensation products of aniline and at least one mono-aldehyde containing one to seven carbon atoms in combination with at least an equal amount of an inorganic base.
A saturated halogen-containing polymer containing at least about 2% by weight of halogen and less than 0.1 mole % ethylenic unsaturation cross-linked by heating in the presence of 2,5-dimercapto-1,3,4-thiadiazole and a basic material selected from (1) amines having a boiling point above about 110.degree. C. and a pK value below about 4.5;
- (2) salts of amines having pK values below about 4.5 with acids having pK values above about 2.0;
- (3) quaternary ammonium hydroxides and their salts with acids having pK values above about 2.0;
- (4) diphenyl- and ditolyl-guanidines;
- and (5) the condensation products of aniline and at least one mono-aldehyde containing one to seven carbon atoms in combination with at least an equal amount of an inorganic base.
A cross-linkable composition comprising (a) a saturated, halogen-containing polymer containing at least about 2% by weight of halogen and less than 0.1 mole % ethylenic unsaturation, (b) 2,5-dimercapto- 1,3,4-thiadiazole and (c) a basic material selected from (1) amines having a boiling point above about 110.degree. C. and a pK value below about 4.5;
- (2) salts of amines having pK values below about 4.5 with acids having pK values above about 2.0;
- (3) quaternary ammonium hydroxides and their salts with acids having pK values above about 2.0;
- (4) diphenyl- and ditolyl-guanidines;
- and (5) the condensation products of aniline and at least one mono-aldehyde containing one to seven carbon atoms in combination with at least an equal amount of an inorganic base.
Dependencies are inferred from the claim text.