Polymer compositions
First Claim
1. A water-insoluble hydrophilic polymer network comprising polyorganosiloxane polyoxyalkylene block copolymer moieties of the form PS-(A-PO)m-(A-PS)n or PS-(A-PO-A-PS)n wherein PS represents a polyorganosiloxane block with a degree of polymerization of 10 to 30, PO represents a polyoxyethylene block with a degree of polymerization of from 4 to 40 oxyethylene units, A represents a divalent radical and m and n have a value of at least 1, wherein the sum of the degree of polymerization of the polyorgansiloxane blocks and the degree of polymerization of the polyoxyethylene block in the block copolymer are each in the range 15 to 35, wherein at least three polysiloxane polyoxyalkylene block copolymer moieties are linked to each other through an organosilicon cross-linking moiety selected from a branched siloxane comprising one or more Q units of the formula (SiO4/2), from 0 to 250 D units of the formula Rb2SiO2/2 and M units of the formula RaRb2SiO1/2, wherein the Ra and Rb substituents are selected from alkyl and alkenyl groups having 1 to 6 carbon atoms, at least three Ra substituents in the branched siloxane being alkenyl units, provided that the cross-linking moiety forming the links between polyorganosiloxane polyoxyalkylene block copolymer moieties result from an addition reaction between silicon-bonded hydrogen atoms cross-linking sites present on the polyorganosiloxane polyoxyalkylene block copolymer and the alkenyl groups present on the branched siloxane prior to formation of the hydrophilic polymer network.
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Abstract
The invention relates to a water-insoluble hydrophilic polymer network comprising polyorganosiloxane polyoxyalkylene block copolymer moieties characterized that they are linked to each other through an organosilicon cross-linking moiety, provided that the cross-linking moiety forming the links between polyorganosiloxane polyoxyalkylene block copolymer moieties result from an addition reaction between cross-linking sites present on the polyorganosiloxane polyoxyalkylene block copolymer moieties prior to formation of the hydrophilic polymer network, selected from silicon-bonded hydrogen atoms and aliphatically unsaturated groups, and reactive groups present on the cross-linking moiety prior to formation of the hydrophilic polymer network. Also disclosed is a process for making the polymer network, and a curable composition able to be reacted into such polymer network.
54 Citations
6 Claims
- 1. A water-insoluble hydrophilic polymer network comprising polyorganosiloxane polyoxyalkylene block copolymer moieties of the form PS-(A-PO)m-(A-PS)n or PS-(A-PO-A-PS)n wherein PS represents a polyorganosiloxane block with a degree of polymerization of 10 to 30, PO represents a polyoxyethylene block with a degree of polymerization of from 4 to 40 oxyethylene units, A represents a divalent radical and m and n have a value of at least 1, wherein the sum of the degree of polymerization of the polyorgansiloxane blocks and the degree of polymerization of the polyoxyethylene block in the block copolymer are each in the range 15 to 35, wherein at least three polysiloxane polyoxyalkylene block copolymer moieties are linked to each other through an organosilicon cross-linking moiety selected from a branched siloxane comprising one or more Q units of the formula (SiO4/2), from 0 to 250 D units of the formula Rb2SiO2/2 and M units of the formula RaRb2SiO1/2, wherein the Ra and Rb substituents are selected from alkyl and alkenyl groups having 1 to 6 carbon atoms, at least three Ra substituents in the branched siloxane being alkenyl units, provided that the cross-linking moiety forming the links between polyorganosiloxane polyoxyalkylene block copolymer moieties result from an addition reaction between silicon-bonded hydrogen atoms cross-linking sites present on the polyorganosiloxane polyoxyalkylene block copolymer and the alkenyl groups present on the branched siloxane prior to formation of the hydrophilic polymer network.
Specification