| 摘要 |
1301158 Carboxylic polysiloxanes; papersizing compositions DOW CORNING CORP 3 July 1970 [5 Aug 1969] 32413/70 Headings C3S and C3T [Also in Divisions D1 and D2] A carboxylic polysiloxane for sizing paper comprises 50-99À9 mol. per cent of units R n SiO (4-n)/2 and 0À1-50 mol. per cent of units HOOCR<SP>1</SP>SiR m(3-m)/2 , wherein R is an optionally substituted hydrocarbon radical, R<SP>1</SP> is a divalent group attached to Si by a C atom, n is 0, 1, 2 or 3 and m is 0, 1 or 2, at least 90 mol. per cent of the siloxane units containing an R radical having at least one methyl radical, at least 90 mol. per cent of the siloxane units containing two organic groups and the average number of organic groups per siloxane unit being 1À8 to 2À1. In examples such polysiloxanes are prepared by cohydrolysis of MeOOC(CH 2 ) 3 SiMe(OMe) 2 with Me 2 Si(OMe) 2 or [Me 2 SiO] 3 (Examples 1 and 2); by addition of acrylic acid to and copolymerization of the product with a cyclic dimethylpolysiloxane (Example 3); and by addition of thioglycolic acid to a copolymer of units Me 2 SiO and MeViSiO (Examples 4 and 5). |
