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US 9,926,338 B2Granted
Carboxylic acid functional siloxanes of defined structure
AssigneeWacker Chemical Corporation
InventorsDaniel Calimente, Timothy McCormack
Life of this patent
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Abstract
Organopolysiloxanes bearing regularly spaced pendent carboxylic acid groups or salts thereof have a block polymer structure and are derived by the double half-esterification of a dianhydride and a silanol- or carbinol-functional organopolysiloxane or sulfur analog thereof. The products can form stable aqueous dispersions without the need for a surfactant.
Claims20
A non-crosslinked, linear organopolysiloxane bearing a plurality of non-terminal chain-pendent carboxylic-acid groups and non-terminal in-chain ester groups, prepared by a process comprising:
- a) reacting one or more difunctional, anhydride-reactive components comprising linear organopolysiloxanes bearing two terminal silanol groups or two terminal carbinol groups, with
- b) a dianhydride component comprising two terminal cyclic dicarboxylic acid anhydride groups,
- reacting taking place under conditions such that at least 80 mol percent of chain-pendent carboxylic acid groups resulting from a ring-opening esterification of silanol groups or carbinol groups and cyclic anhydride groups remain non-esterified, and wherein non-esterified carboxylic acid groups are optionally present in the form of a carboxylate salt.
Dependencies are inferred from the claim text.