Reference

Correction of: earlier abstract Latent hardeners for epoxy resins. Miyashiro, James J. (Morton-Norwich Products, Inc., USA). Ger. Offen. DE 2418754 7 Nov 1974, 23 pp. (German). (Germany). CODEN: GWXXBX. CLASS: IC: C08G030-14. PRIORITY: US 73-352201 18 Apr 1973. DOCUMENT TYPE: Patent CA Section: 36 (Plastics Manufacture and Processing) Epoxy resin compns. having a long pot life but hardening rapidly at high temp. are prepd. by mixing the resins with a latent hardener or hardening accelerator comprising either a mixt. or reaction products prepd. from tetrahydrophthalic anhydride (I) [85-43-8] or chlorendic anhydride [115-27-5] and imidazole [288-32-4] or a deriv. such as 2-methylimidazole (II)a [693-98-1]. Thus, 10 parts epoxy cresol novolak resin and 5 parts phenolic novolak resin were mixed with 0.17 part II and 0.33 part I or with 0.5 part product prepd. 51-17-2 and 931-36-2 which are cas registry numbers of chemicals are mentioned. by heating 10 g I and 2.5 g II at 135.degree. for 30 min, giving resins with hardening time 18-20 sec at 180.degree.. Correction of CA t. .

Heat-resistant epoxy curing agents

Heat-resistant epoxy curing agents. (Dainippon Ink and Chemicals, Inc., Japan). Jpn. Kokai Tokkyo Koho JP 58089612 A2 28 May 1983 Showa, 5 pp. (Japanese). (Japan). CODEN: JKXXAF. CLASS: IC: C08G059-42. APPLICATION: JP 81-186840 24 Nov 1981. DOCUMENT TYPE: Patent CA Section: 37 (Plastics Manufacture and Processing) Mixts. of 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride (I) [73003-90-4], chlorendic anhydride (II) [115-27-5], and liq. dicarboxylic anhydrides are heat-resistant, liq. curing agents for epoxy resins. Thus, I 15, II 15, and methyltetrahydrophthalic anhydride (III) [26590-20-5] 70 parts were mixed at 150° and cooled to 25° to a homogeneous, transparent liq. with viscosity 230 cP, showing no pptn. after 1 mo in a sealed container. This liq. 91, Epiclon 850 [25068-38-6] (bisphenol A epoxy resin) 100, and 2-ethyl-4-methylimidazole catalyst 1 part were mixed and cured 5 h at 80° and 5 h at 160° to specimens with heat distortion temp. 145° and flexural strength 11.3 kg/mm2, compared to 120° and 13.0, resp., with I-III as curing agent.