| 摘要 |
1289633 Polycondensation catalysts SANDOZ Ltd 21 Jan 1970 [29 Jan 1969] 3015/70 Addition to 1236477 Heading C3R Polyesters are prepared using metallic titanium as polycondensation catalyst wherein the polyester is derived from aromatic and/or aliphatic dicarboxylic acids, e.g. iso- or terephthalic, naphthalene-2,6-dicarboxylic, diphenyldicarboxylic, adipic or sebacic acids, or lower alkyl esters thereof, and an aliphatic and/or cycloaliphatic and/or aromatic dihydric alcohol, e.g. a C 2-10 alkanediol, diethylene glycol, or 1,4-bis- (4<SP>1</SP>-#-hydroxyethoxy-phenyl)-propane. In the examples titanium catalysts having particle sizes up to 100 Á are used to prepare poly- (ethylene terephthalate). |
