Dow Corning Corporation

Geraldine Durand

Sarah Louise O'Hare

Iain A Mackinnon

Francois De Buyl

Helen L Gough

A polyorganosiloxane polyoxyalkylene block copolymer having one or more polyorganosiloxane blocks and one or more polyoxyalkylene blocks linked to each other via divalent radicals which comprises at least two silicon-bonded alkoxy groups, preferably of the form PS (A PO)(A PS), wherein PO is a polyoxyalkylene block, PS represents a polyorganosiloxane block, A is a divalent radical, m and n have independently a value of at least 1, comprising at least one alkoxy-substituted siloxane unit of the formula (R')(OR)&#x2014;SiO, wherein R represents an alkyl group having 1 to 4 carbon atoms and each R&#x2032; represents an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an alkoxy group of the formula &#x2014;OR and q has a value of 0, 1 or 2, provided at least two silicon-bonded groups OR are present in the block copolymer. Also provided is a curable composition of the above which may comprise a condensation catalyst and a hydrophilic polymer network made from curing the composition in the presence of moisture, which exhibit interesting reversible hydrophilic properties.

Polymer and polymer compositions

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.

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Messas, United Kingdom

Geraldine Durand