| 摘要 |
1293818 Curing epoxy resins CIBA-GEIGY AG 9 Nov 1970 [12 Nov 1969] 53232/70 Heading C3B [Also in Division C2] Curable mixtures comprise a polyepoxide and as curing agent a polycarboxylic acid which is liquid at room temperature and has the formula in which R is H or Me, Z is a hydrocarbon radical obtained by removing the OH groups of a n-hydric aliphatic or cycloaliphatic alcohol or an alkylene radical interrupted by oxygen atoms and n=2, 3 or 4. I may be prepared by reacting a tricarboxylic acid anhydride with an n-hydric alcohol (see Division C2). Preferred are the tetra- and hexa-carboxylic acids in which n is 2 or 3. Examples relate to the curing of a diglycidyl ether of bisphenol A, cycloaliphatic diepoxides and (N,N<SP>1</SP>-methylene-bis-[3-glycidyl- 5,5-dimethylhydantoin]). A typical curing agent is prepared by reacting 2 moles of ethylene glycol with 4 moles of butane-1,2,4-tricarboxylic anhydride to yield a tetracarboxylic acid. Uses.-Mouldings, electrical insulation and coatings. |
