PROCESS FOR PREPARING HIGHER MOLECULAR WEIGHT POLYEPOXIDE PRODUCTS BY REACTING A POLYEPOXIDE WITH A PHENOL IN PRESENCE OF TETRAALKYLAMMONIUM HALIDES

摘要

1364804 Polyepoxides SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ NV 19 Jan 1973 [21 Jan 1972] 3101/72 Heading C3B A polyepoxide product is prepared by condensing a polyhydric phenol at a temperature of 120-200‹ C. with a polyepoxide starting material having a molecular weight which is below 3500 which is lower than the M.wt. of the polyepoxide product, in the presence of from 0-1% wt., based on polyepoxide starting material, of an inert solvent having an atmospheric boiling point of at least 140‹ C. and which is miscible with the product and reactants, and in the presence of 0À05 to 2 milliequivalents of a quaternary ammonium halide catalyst per 100 g. of polyepoxide starting material, the initial ratio of phenolic hydroxyl groups to epoxy group being below 1 : 1À05. Preferred polyepoxide starting materials are glycidyl polyethers of polyhydric phenols such as Novolac resins, 1,1 - bis - (4 - hydroxyphenyl)ethane, bis - (4 - hydroxyphenyl)methane, bis - (4- hydroxyphenyl)sulphone and 2,2 - bis - (4- hydroxyphenyl)propane. Preferred polyhydric phenols are bisphenols particularly 2,2-bis- (hydroxyphenyl)propane. Preferred catalysts are tetra-alkylammonium halides. In Examples 1 and 2 polyepoxides are prepared in the absence of an inert solvent by condensing either (I) 2,2 - bis - (4 - hydroxyphenyl)propane or (II) a mixture of (I) with a minor amount of 2-(4- hydroxyphenyl) - 2 - (2 - hydroxyphenyl)propane with either the diglycidyl ether of (I) or the diglycidyl ether of (II) in the presence of tetramethylammonium chloride as catalyst. The polyepoxide products were mixed with a polyamino-amide curing agent (VERSAMID, Registered Trade Mark), titania pigment and an organic solvent and sprayed on to steel panels. The coatings were cured at 23‹ C. for 7 days. In Example 4 similar polyepoxides are prepared using instead as catalyst either hexadecyltrimethylammonium bromide or glycidyl trimethylammonium chloride.