| 摘要 |
1,174,344. Coating. CIBA (A.R.L.) Ltd. 23 Jan., 1968 [13 Feb., 1967], No. 6762/67. Headings B2E and B2K. [Also in Divisions C3 and C7] Substrates, e.g. of aluminium are coated with a curable composition comprising: (a) a material formed by heating, e.g. at 80-130‹C for 1-3 hours, a liquid mixture of a polycarboxylic acid anhydride with an epoxide alcohol fine from canboxyl groups, so that at least 40% of the alcoholic, OH groups of the epoxide alcohol are esterified but not more than 25% of the epoxy groups react with the polycarboxylic acid anhydride; (b) a base e.g. ammonia, NaOH or KOH or an organic amine, in a quantity sufficient to neutralise at least some of the carboxyl groups of component (a); and (c) optionally a curing agent for component (a). An epoxide alcohol is defined as a compound containing at least one epoxide group and at least one alcoholic OH group which is preferably primary or secondary. Preferred are diglycidyl ethers of bisphenol A which contain secondary hydroxyl groups in the polymer chain but one example relates to a cyclic monoepoxy compound having a hydroxyl group. The acid anhydride may be used in a quantity such as to supply from 0.4 to 1.3 anhydride equivalents per OH group equivalent of the epoxide alcohol. The epoxide alcohol preferably contains no groups other than hydroxyl and epoxy groups capable of reacting with the anhydride and conversely the anhydride should contain no other substituents capable of reacting with hydroxyl or epoxy groups. The composition may also contain water and a substance, e.g. an amphipathic solvent which renders the neutralised component soluble. The composition may also contain a melamine resin or an acyclic resin, e.g. a copolymer of acyclic acid, butyl acrylate and styrene neutralised with ammonia. Conventional pigments may also be present. |
