Patent ID: 8357762

Claim:
An organopolysiloxane mixture comprising cyclic organopolysiloxanes, liner organopolysiloxanes and urea hydrochloride, obtained by hydrolysis and polycondensation of an organosilicon material comprising a first organosilicon compound and/or a partial hydrolytic condensate thereof and optionally, a second organosilicon compound and/or a partial hydrolytic condensate thereof, in the presence of urea hydrochloride said first organosilicon compound having the general formula (1): XSi(OR 1 ) 3 (1) wherein X is a C 1 -C 18 monovalent hydrocarbon radical which may have at least one functional radical selected from the group consisting of mercapto, epoxy, (meth)acryloxy, alkenyl, amino, and halogen, and R 1 is a C 1 -C 4 monovalent hydrocarbon radical, said second organosilicon compound having the general formula (2): Y r R 2 s Si(OR 1 ) (4-r-s) (2) wherein Y is a C 1 -C 18 monovalent hydrocarbon radical which may have at least one functional radical selected from the group consisting of mercapto, epoxy, (meth)acryloxy, alkenyl, amino, and halogen, R 2 is a C 1 -C 3 monovalent hydrocarbon radical different from Y, R 1 is a C 1 -C 4 monovalent hydrocarbon radical, r is 0, 1 or 2, s is 0 or 1, and r+s is 0, 1, 2 or 3, with the proviso that Y is different from X in formula (1) when r is 1 and s is 0, wherein the organopolysiloxane mixture has a polydispersity index (Mw/Mn) of no more than 1.2, given as a weight average molecular weight (Mw) divided by a number average molecular weight (Mn) as measured by gel permeation chromatography versus polystyrene standards, and the organopolysiloxane mixture, when analyzed by silicon nuclear magnetic resonance spectroscopy, exhibits a peak component (T 2 ) assigned to siloxane units formed by hydrolytic condensation between two alkoxy radicals on the first organosilicon compound and/or partial hydrolytic condensate thereof, said peak component (T 2 ) including a peak component (T 2 a ) assigned to the cyclic constituent and a peak component (T 2 b ) assigned to the linear constituent in a ratio (T 2 a /T 2 b ) of at least 0.9.