Solventless liquid organopolysiloxanes

A process for producing a solventless organopolysiloxane resin that is liquid at room temperature, the process including the steps of:

• hydrolyzing, in an aqueous system, by heating a hydrolyzable organo silicon composition comprising at least one compound having the general formula:
• Y.sub.(4-n) Si(OR).sub.n
• where Y is phenyl or methyl, R is an alkyl group having from one to three carbon atoms, and n is an integer from one to four, wherein the ratio of OR groups to silicon atoms in the composition is from about 2.3:1 to 3.1:1, the molar ratio of water/silane being about 1.5:1 to 2.25:1, and the amount of acid present expressed as HCl being about 2.3 to 1192 parts of HCl per million parts of silane and water to form a siloxane partial condensation product,
• concentrating the partial condensation product by heating to cause substantial siloxane formation by condensation and to distill therefrom water and alcohol by-products,
• precuring the concentrated partial condensation product by heating the product to remove volatile material at a temperature equivalent to that of about 140.degree. C. to 160.degree. C. for about 2 hours, and
• cooling the precured product to room temperature to provide a solventless organopolysiloxane that has a viscosity at 25.degree. C. measured by a Brookfield LVT viscometer using a #3 spindle at 60 rpm of at least about 25 cps. but not greater than 10,000 cps, the solventless organopolysiloxane having a water content by weight of less than about 1 percent.