Stable ethylsilicate polymers

摘要

An stable ethylsilicate polymer having a dynamic viscosity of 10 centipoises (cps) to 1,000 cps at 25° C. and 50 wt % to 60 wt % silica (SiO2). The stable ethylsilicate polymer includes not greater than 1 wt % of TEOS monomer. The process of forming the ethylsilicate polymer includes a two step addition of catalysts. A hydrolysis catalyst is added initially, for example hydrochloric acid, and a second catalyst is added subsequently, such as phosphonitrilic chloride trimer. The ethylsilicate polymer is used to form MQ resins.

主权项

1. An ethylsilicate polymer comprising the reaction products of a mixture of tetraethyl orthosilicate monomer with a mineral acid hydrolysis catalyst, ethanol, acidified water, and a phosphoronitrilic chloride condensation catalyst;
said ethylsilicate polymer comprising 50 wt % to 60 wt % silica (SiO2), not greater than 1 wt % monomers, and not greater than 1 wt % of at least one linear oligomer, based on the total weight of said ethylsilicate polymer; wherein said linear oligomer has a molecular weight at peak (Mp) of not greater than 210 g/mol; and wherein said ethylsilicate polymer has a dynamic viscosity of 10 cps to 1000 cps at 25° C., and wherein said ethylsilicate polymer will remain in a liquid form even after heating at 55° C. for 20 days.