Methods for making polyfunctional organosiloxanes and compositions containing same

A method for preparing a product comprising:

• 1) reacting starting materials comprising
• B) a hydroxyl terminated polydiorganosiloxane of formula
• where subscript n is 2 to 2,000, and each R1 is independently selected from the group consisting of monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups;
• and
• C) a cyclic polyorganohydrogensiloxane of formula (RHSiO2/2)v, where subscript v is 3 to 12;
• and each R is an independently selected monovalent hydrocarbon group;
• thereby preparing the product comprising a polyfunctional organohydrogensiloxane and a by-product comprising H2
• in the presence of A) a boron containing Lewis acid, thereby preparing the product, which comprises a polyfunctional organohydrogensiloxane and a by-product comprising H2;
• where the polyfunctional organohydrogensiloxane has unit formula:
• [(HRSiO2/2)v-1(—RSiO2/2)]2[O—(R12SiO2/2)n]n′[(HRSiO2/2)v-2(—RSiO2/2)2]o′, where
• subscripts n and v and R1 and R are as described above,
• subscript o′ is 0 to 1, and
• subscript n′=(o′+1),
• 2) during and/or after step 1), removing the H2 generated during formation of the polyfunctional organohydrogensiloxane,
• 3) neutralizing residual boron containing Lewis acid in the polyfunctional organohydrogensiloxane, and
• 4) removing a particulate derived from neutralizing the boron containing Lewis acid in step 3).

A method for preparing a product comprising:

• 1) reacting starting materials comprising
• B) a hydroxyl terminated polydiorganosiloxane of formula
• where subscript n is 2 to 2,000, and each R1 is independently selected from the group consisting of monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups;
• and
• C) a cyclic polyorganohydrogensiloxane of formula (RHSiO2/2)v, where subscript v is 3 to 12;
• and each R is an independently selected monovalent hydrocarbon group;
• in the presence of A) a boron containing Lewis acid;
• thereby preparing a reaction product comprising a polyfunctional organohydrogensiloxane and a by-product comprising H2;
• optionally 2) during and/or after step 1), removing the H2 generated during formation of the polyfunctional organohydrogensiloxane;
• optionally 3) neutralizing residual boron containing Lewis acid in the polyfunctional organohydrogensiloxane;
• wherein steps 1), 2) and 3) are free of platinum group metal catalysts;
• optionally 4) removing a particulate derived from neutralizing the boron containing Lewis acid in step 3);
• optionally 5) recovering the polyfunctional organohydrogensiloxane;
• and
• 6) combining starting materials comprising
• a) the polyfunctional organohydrogensiloxane,
• b) a hydrosilylation reaction catalyst, and
• c) a reactive species having an average, per molecule at least one aliphatically unsaturated group capable of undergoing an addition reaction with a silicon bonded hydrogen atom of starting material a) and further comprising one or more curable groups per molecule;
• thereby preparing the product, which comprises a clustered functional organosiloxane of unit formula:
• [(R8RSiO2/2)v-1(—RSiO2/2)]2[O—(R12SiO2/2)n]n′[(R8RSiO2/2)v-2(—RSiO2/2)2]o′,
• where subscripts v and n and groups R and R1 are as described above;
• subscript o′ is 0 to 100, subscript n′=(o′+1);
• and each R8 is independently selected from the group consisting of H and a curable group, with the proviso that at least one R8 per molecule is a curable group other than hydrogen.