Room temperature stable organopolysiloxane compositions
AssigneeWacker Silicones Corporation
InventorGeorge J. Viksne
Life of this patent
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Abstract
Compositions which are stable at room temperature, but when heated to an elevated temperature crosslink to form elastomeric solids comprising (A) organopolysiloxanes containing silicon bonded hydroxyl groups, (B) a crosslinking agent selected from (a) silanes, (b) partial hydrolyzates thereof and (c) organohydrogenpolysiloxanes and (C) an aluminum salt of a carboxylic acid which is a solid at room temperature. When the compositions are heated to a temperature of at least 50.degree. C. and more preferably from 100.degree. to 350.degree. C., they cure to form elastomeric solids.
Claims16
A composition which is stable at room temperature, but when heated to an elevated temperature cures to an elastomeric solid which comprises (A) an organopolysiloxane having silicon bonded hydroxyl groups, (B) a crosslinking agent selected from the group consisting of
- (a) a silane of the formula
- R.sub.m Si(Z).sub.4-m,
- (b) partial hydrolyzates of silane (a) and
- (c) an organohydrogenpolysiloxane of the average unit formula
- R.sub.n HSiO.sub.3-n
- where R is selected from the group consisting of a monovalent hydrocarbon radical having from 1 to 18 carbon atoms and a substituted monovalent hydrocarbon radical having from 1 to 18 carbon atoms, Z is selected from the group consisting of a hydrocarbonoxy group of the formula (--OR') and a hydrocarbonoxy-hydrocarbonoxy group of the formula (--OR"OR'), where R' is a monovalent hydrocarbon radical having from 1 to 10 carbon atoms, R" is a divalent hydrocarbon radical having from 2 to 10 carbon atoms, m is an integer of from 0 to less than 2 and n is an integer greater than 0, but less than 2 and (C) an aluminum salt of a carboxylic acid having from 8 to 18 carbon atoms which is solid at room temperature.
A process for preparing a composition which is stable at room temperature, but when heated to an elevated temperature cures to elastomeric solid which comprises mixing (A) an organopolysiloxane having silicon bonded hydroxyl groups with (B) a crosslinking agent selected from the group consisting of
- (a) a silane of the formula
- R.sub.m Si(Z).sub.4-m,
- (b) partial hydrolyzates of silane (a) and
- (c) an organohydrogenpolysiloxane of the average unit formula
- R.sub.n HSiO.sub.3-n
- where R is selected from the group consisting of a monovalent hydrocarbon radical having from 1 to 18 carbon atoms and a substituted monovalent hydrocarbon radical having from 1 to 18 carbon atoms, Z is selected from the group consisting of a hydrocarbonoxy group of the formula (--OR') and a hydrocarbonoxy-hydrocarbonoxy group of the formula (--OR"OR'), where R' is a monovalent hydrocarbon radical having from 1 to 10 carbon atoms, R" is a divalent hydrocarbon radical having from 2 to 10 carbon atoms, m is an integer of from 0 to less than 2 and n is an integer greater than 0, but less than 2 and (C) an aluminum salt of a carboxylic acid having from 8 to 18 carbon atoms which is solid at room temperature.
Dependencies are inferred from the claim text.