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US 6,689,859 B2Granted
High fracture toughness hydrosilyation cured silicone resin
AssigneeDow Corning Corporation
InventorsZhongtao Li, Frederick J. McGarry, John R. Keryk, Bizhong Zhu, Dimitris E. Katsoulis
Life of this patent
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Abstract
A hydrosilylation reaction curable composition that includes a silsesquioxane polymer, a mixture of silanes or siloxanes as a cross-linking compound and a hydrosilylation reaction catalyst. The curable composition is cured to form a cured resin having high fracture toughness and strength without the loss of elastic modulus.
Claims13
A hydrosilylation reaction curable composition comprising:
- a) a silsesquioxane polymer comprising a copolymer resin having the empirical formula R1aR2bR3cSiO(4−a−b−c)/2, wherein:
- a is zero or a positive number, b is zero or a positive number, c is zero or a positive number, with the provisos that 0.8≦(a+b+c) ≦3.0 and component (A) has an average of at least 2 R1 groups per molecule, and each R1 is independently selected from monovalent hydrocarbon groups having aliphatic unsaturation, and each R2 and each R3 are independently selected from monovalent hydrocarbon groups and hydrogen;
- b) a mixture of silane and/or siloxane cross-linking compounds;
- and
- c) a hydrosilylation reaction catalyst;
- the cured composition displaying a fracture toughness that is greater than the fracture toughness of a cured composition formed utilizing any of the individual cross-linking compounds of the mixture alone.
3 more elements
A process for preparing a hydrolsilylation reaction cured composition comprising the steps of:
- a) providing a silsesquioxane polymer comprising a copolymer resin having the empirical formula R1aR2bR3cSiO(4−a−b−c)/2, wherein:
- a is zero or a positive number, b is zero or a positive number, c is zero or a positive number, with the provisos that 0.8≦(a+b+c)≦3.0 and component (A) has an average of at least 2 R1 groups per molecule, and each R1 is independently selected from monovalent hydrocarbon groups having aliphatic unsaturation, and each R2 and each R3 are independently selected from monovalent hydrocarbon groups and hydrogen;
- b) providing a mixture of silanes or siloxanes as a cross-linking compound;
- c) mixing the components of a), b), to form a curable composition;
- d) adding a hydrosilylation reaction catalyst to the curable composition of step c)
- e) curing the curable composition of step d) to form a cured resin having a fracture toughness that is greater than the fracture toughness of a cured composition utilizing any of the individual cross-linking compounds of the mixture alone.
3 more elements
Dependencies are inferred from the claim text.