Patent GB-1494541-A (GB)
Title: Method of producing polysiloxane-polyoxyalkylene block copolymers
IPC: C08G77/50
Filed: 1975-02-06
Abstract: 1494541 Polysiloxane-polyoxyalkylene block copolymers; polyurethane foams TH GOLDSCHMIDT AG 12 Jan 1976 [6 Feb 1975] 5160/75 Headings C3T and C3R Polysiloxane-polyoxyalkylene block copolymers in which the polyoxyalkylene blocks are attached laterally, i.e. like the teeth of a comb, to the polysiloxane block and which contain structural units of the formula where R<SP>1</SP> is an alkylene radical, R<SP>2</SP> is a monovalent hydrocarbon radical and/or a trialkylsilyloxy radical, OP is a polyoxyalkylene block derived from an alcohol POH, and p is 1 or 2 are prepared by a process which comprises additively attaching, in a first step, a silane of the formula where R<SP>3</SP> is an alkenyl radical and X is a halogen atom or an alkoxy radical, to a mixture of equilibrated linear polysiloxanes containing SiH-groups, and having the formula where R<SP>5</SP> is an unsubstituted or substituted alkyl or aryl radical, Y is a halogen atom, an alkoxy radical or an organosulphonic acid residue, m is from 1À57 to 30, and n is a number such that the average molecular weight of the polysiloxanes is from 500 to 12,000, and reacting this intermediate product in a second step with a polyoxyalkylene monool alone or in admixture with one or more polyoxyalkylene diols and/or C 1 -C 6  alcohols thereby to replace the X and Y atoms or radicals by polyoxyalkylene blocks. The R<SP>5</SP> radical preferably represents CH 3  but it may also be C 2 H 5 , n-C 3 H 7 , nC 8 H 17 , -CH 2 Br, -(CH 2 ) 3 Cl, -(CH 2 ) 2 C 6 H 5 , -(CH 2 ) 3 OCOCH 3 , -(CH 2 ) 2 CF 3 , phenyl. -(CH 2 ) 3 -O-alkyl or -(CH 2 ) 3 OCF(CF 3 ) 2 . The R<SP>3</SP> radical in the silane is preferably vinyl or allyl. The polyoxyalkylene mono-ol preferably has a M.wt. of 400-6000 and is preferably an addition product of ethylene oxide and/or propylene oxide with an alcohol or a phenol, The block copolymer may be stabilized against hydrolysis by the addition of an amine, e.g. an alkanolamine, and can be used as textile lubricants; in cosmetics; antifoams; demulsifiers for oil-in-water emulsions; and as foam stabilizers in the production of urethane foams. In a particular example a block copolymer of formula in which R<SP>2</SP> and R<SP>5</SP> are methyl, R<SP>1</SP> is -(CH 2 ) 2 -, n is 40, m is 3 and p is 2 is prepared by equilibrating a chlorosiloxane prepared by the partial hydrolysis of dimethyldichlorosilane and methyldichlorosilane using methanesulphonic acid as equilibration catalyst and reacting the equilibrated chlorosiloxane with dimethylvinyl chlorosilane in the presence of (ethylene), (pyridine) PtCl 2  as catalyst, and reacting the resulting intermediate with a mixture of 2 polyether monools of different M.wt. which are propylene oxide/ethylene oxide/n-butanol adducts. Ethanolamine is added to the block copolymer. The block copolymer produced is used as a foam stabilizer in the production of a polyurethane foam from a formulation comprising an ethylene oxide/propylene oxide/ glycerol adduct, water, trichlorofluoromethane, tin octoate, dimethylethanolamine, N-ethylmorpholine, tolylene diisocyanate and the siloxane-polyether block copolymer.