Nova Patents
EP0802233A2

Organosiloxane compositions

Abstract

A moisture curable composition comprises a mixture and/or a reaction product of a polymeric material having not less than two groups bonded to silicon which are hydroxyl or hydrolysable groups, an alkoxysilane curative, an adhesion promoter and catalyst material for catalysing the condensation reaction between the polymeric material and the alkoxysilane curative. The adhesion promoter comprises a silicone-organic copolymer consisting of units (i) according to the general formula RaSiO4-a/2 and units (ii) according to the general formula RbR'SiO3-b/2 where R represents a monovalent hydrocarbon group and R' represents an oxyalkylene chain R"(C2H4O)x(C3H6O)yZ in which R" represents a hydrocarbon linkage to a silicon atom, Z represents H or a carboxylic acid residue. Also disclosed is a method of forming an elastomeric mass between surfaces which is adherant to at least two such surfaces which method comprises introducing between the surfaces said moisture curable composition.

Term

Term ended

Projected expiry passed 8 April 2017, 9.5 years ago.

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7 claims: 1 independent, 6 dependent

  1. 1
    A method of forming an elastomeric mass between surfaces which is adherent to at least two such surfaces which method comprises introducing between the surfaces a mass of a moisture curable composition which comprises a mixture and/or a reaction product of a polymeric material having not less than two groups bonded to silicon which are independently selected from hydroxyl and other hydrolysable groups, an alkoxysilane curative, a finely divided filler and catalyst material for catalysing a condensation reaction between the polymeric material and the alkoxysilane curative, characterised in that the composition further includes an adhesion promoter which comprises a silicone-organic copolymer consisting of units (i) according to the general formula R a SiO 4-a/2 and units (ii) according to the general formula R b R'SiO 3-b/2 where each R is the same or different and represents a monovalent hydrocarbon group having up to 20 carbon atoms, each a is the same or different and has a value from 0 to 3, each b is the same or different and has a value from 0 to 2 and R' is the same or different and represents an oxyalkylene chain R"(C 2 H 4 O) x (C 3 H 6 O) y Z where R" represents a hydrocarbon linkage to a silicon atom, each Z is the same or different and represents H or a carboxylic acid residue, each x is the same or different and has a value from 0 to 20 and each y is the same or different and has a value from 0 to 20 and x + y has a value from 3 to 40.
  2. 2
    A method according to Claim 1 further characterised in that the groups R' of the units (ii) provide no more than 40% by weight of the silicone organic copolymer.
  3. 3
    A method according to Claim 1 or 2 further characterised in that the polymeric material is an at least substantially linear polydiorganosiloxane having terminal groups SiMe 2 OH or SiMe 2 R"'Si(OR 5 ) 3 wherein R"' is a divalent hydrocarbon group which may be interrupted by one or more siloxane spacers having up to 6 silicon atoms and R 5 represents an alkyl or oxyalkyl group in which the alkyl groups have up to 6 carbon atoms.
  4. 6
    A method for promoting adherence of an elastomeric mass to two or more surfaces, which elastomeric mass is formed from a moisture curable composition comprising a mixture and/or a reaction product of a polymeric material having not less than two groups bonded to silicon which are independently selected from hydroxyl and other hydrolysable groups, an alkoxysilane curative, a finely divided filler and catalyst material for catalysing a condensation reaction between the polymeric material and the alkoxysilane curative, characterised in that the method comprises including an adhesion promoter in the composition, which adhesion promoter comprises a silicone organic copolymer consisting of units (i) according to the general formula R a SiO 4-a/2 and units (ii) according to the general formula R b R'SiO 3-b/2 where R, a, b and R' are as defined in Claim 1.
  5. 7
    A moisture curable composition which comprises a mixture and/or a reaction product of a polymeric material having not less than two groups bonded to silicon which are independently selected from hydroxyl and other hydrolysable groups, an alkoxysilane curative, a finely divided filler and catalyst material for catalysing a condensation reaction between the polymeric material and the alkoxysilane curative, characterised in that the composition further includes an adhesion promoter which comprises a silicone-organic copolymer consisting of units (i) according to the general formula R a SiO 4-a/2 and units (ii) according to the general formula R b R'SiO 3-b/2 where R, a , b and R' are as defined in Claim 1.