SILOXANE RESINS

摘要

This invention pertains to a siloxane resin composition comprising R<1>SiO3/2 siloxane units and (R<2>O)bSiO(4-b)/2 siloxane units wherein R<1> is an alkyl group having 1 to 5 carbons; R<2> is a branched alkyl group having 3 to 30 carbons, b is from 1 to 3. The siloxane resin contains a molar ratio of R<1>SiO3/2 units to (R<2>O)bSiO(4-b)/2 units of 1:99 to 99:1. The siloxane resin is useful to make insoluble porous resins and insoluble porous coatings. Heating a substrate coated with the siloxane resin at a sufficient temperature effects removal of the R<2>O groups to form an an insoluble porous coating having a a dielectric constant in the range of 2.1 to 3, a porosity in the range of 2 to 40 volume percent and a modulus in the range of 1.9 to 20 GPa.