Process for the production of silicone resins
First Claim
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1. A process for the production of a thermoplastic, high softening point polysiloxane resin which comprises the steps of:
- (a) reacting a solvent-soluble partially condensed organosiloxane having the unit formula;
space="preserve" listing-type="equation">(RSiO.sub.1.5).sub.a (R'"'"'R"SiO).sub.bwherein R and R'"'"' are each independently hydrogen or an organic group, at least 85% of the R groups in the RSiO1.5 units being organic groups, R" is an organic group,a is from 0.6 to 1,b is 0 to 0.4, and a+b=1,and wherein the organosiloxane comprises Si-OH groups capable of further condensation, the percentage by weight, based on the weight of the resin, of said hydroxyl groups being from 1 to 10, with a silane capping agent so as to cap some of the Si--OH groups, and(b) equilibrating the product of step (a) to produce a product having a softening point in excess of 50°
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Abstract
The invention relates to a novel process for the production of a thermoplastic, high softening point polysiloxane resin which comprises reacting a solvent-soluble partially condensed organosiloxane with a silane capping agent. The resins so produced are useful as electrical insulator material and also as hold out agents for heat recoverable articles.
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Citations
33 Claims
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1. A process for the production of a thermoplastic, high softening point polysiloxane resin which comprises the steps of:
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(a) reacting a solvent-soluble partially condensed organosiloxane having the unit formula;
space="preserve" listing-type="equation">(RSiO.sub.1.5).sub.a (R'"'"'R"SiO).sub.bwherein R and R'"'"' are each independently hydrogen or an organic group, at least 85% of the R groups in the RSiO1.5 units being organic groups, R" is an organic group, a is from 0.6 to 1, b is 0 to 0.4, and a+b=1, and wherein the organosiloxane comprises Si-OH groups capable of further condensation, the percentage by weight, based on the weight of the resin, of said hydroxyl groups being from 1 to 10, with a silane capping agent so as to cap some of the Si--OH groups, and (b) equilibrating the product of step (a) to produce a product having a softening point in excess of 50°
C. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification