Patent ID: 7973121

Claim:
A process for preparing a polyorganosiloxane containing in its structure at least one functional group, where each functional group is linked to a silicon atom, comprising reacting a polyorganosiloxane containing in its structure at least one hydroxyl group, where each hydroxyl group is linked to at least one silicon atom, with, per silanol unit (≡Si—OH), at least 1 mol of at least one functionalizing polyalkoxysilane of formula: (R 1 ) a (R 2 ) b Si(OR 3 ) 4-(a+b) (I) in which: R 1 is a linear or branched C 1 -C 10 alkyl radical; a C 5 -C 10 cycloalkyl radical; or a C 6 -C 18 aryl radical; R 2 is a functional group of formula: —(Z) m —(X) n where: m=0 or 1; n=1 or 2; Z is a divalent or trivalent C 1 -C 30 hydrocarbon-based residue optionally containing one or more oxygen atoms, said residue comprising a linear or branched, a saturated or unsaturated aliphatic residue, a cyclanic residue, an aromatic residue, or a mixed aliphatic/aromatic residue; X, when m=0, is an unsaturated linear or branched aliphatic or cyclanic C 2 -C 6 hydrocarbon-based radical containing a double bond and optionally another double bond optionally conjugated to the first double bond; X, when m=1, is a member of the group selected from the group consisting of a chlorine atom, a bromine atom an iodine atom; —O—CO—CR 4 ═CR 5 R 6 in which R 4 , R 5 and R 6 , which may be identical or different, are each a hydrogen atom, a C 1 -C 6 alkyl radical and/or a phenyl radical; the radical —C p F 2p —CF 3 (p equal to 0 or other than 0); the radical —C p′ F 2p′ —H (p′ equal to 1 or greater than 1); —NHR 7 in which R 7 is a hydrogen atom, a linear or branched C 1 -C 6 alkyl radical or a radical —R 8 —NH 2 in which the symbol R 8 is Z; and —SH; R 3 is a linear or branched C 1 -C 4 alkyl radical; a=0, 1, 2 or 3; b=0 or 1; a+b=0, 1, 2 or 3, with the additional condition according to which when the sum a+b=3, the symbol b cannot be a number equal to 0; wherein said reaction occurs in the presence of an effective amount of a catalyst consisting essentially of a lithium organosilanolate of formula: (R 1 ) a (R 2 ) b (OR 3 ) 3-(a+b) SiO − Li + (II) in which the symbols R 1 , R 2 , R 3 , a and b have the meanings given above; and said process is performed in the absence of an aliphatic alcohol of formula R 3 OH added to the reaction medium.