GB972988A - Epoxy resin compositions - Google Patents

Abstract

Polyimines containing a plurality of imine groups, each N atom of which is joined to two aliphatic or cycloaliphatic carbon atoms one by a single bond and the other by a double bond are prepared by condensing a polyamine with a ketone, if desired in presence of a solvent which may be excess ketone or may be an azeotroping solvent to facilitate removal of water. A catalyst, e.g. iodine or HCl may be used. When using acetone, the polyamine is dissolved in excess acetone and the solution left to stand with HCl as a catalyst. Suitable amines are 1,2,3-triaminopropane; tetrakis (aminomethyl) methane; 1,2-ethylene diamine; 1,2, or 1,3-propylene diamine; 1,4-butylene diamine; 1,5-pentylene diamine; 1,6-hexylene diamineo; 1,8-octylene diamine; m-xylyene diamine; 1,2-diaminocyclohexane; and amines of formula <FORM:0972988/C1/1> in which R1 is a divalent hydrocarbon radical forming part of a cycloalkylene, bicycloalkylene or benzocycloalkylene radical. Suitable ketones are acetone; methyl isobutyl ketone; methyl ethyl ketone; di-isobutyl ketone; methyl benzyl ketone; cyclohexanone; methyl cyclohexyl ketone; cyclopentanone; methyl octyl ketone; methyl decyl ketone. In Example A 1,6-hexane diamine and methyl isobutyl ketone were refluxed in benzene with a water separator. The di-imine boiled at 126 DEG C. at 0.2 mm Hg. Example B describes the preparation of the diimine from m-xylylene diamine and methyl isobutyl ketone. Specifications 518,057, 579,698, 598,447, 853,619 905,725 and U.S.A. Specifications 2,324,483, 2,444,333, 2,606,810, 2,607,754, 2,730,427, 2,752,269, 2,828,313, 2,850,532 are referred to.ALSO:A composition of an epoxy resin and a liquid polyimines latent curing agent which has a plurality of imine groups, each N of which is joined to two aliphatic or cycloaliphatic carbon atoms-one by a single and the other by a double bond, is cured by treatment with water which hydrolyses the polyimine to form amine groups. The polyimines may be made by reaction of a polyamine with a ketone. Any epoxy resin may be used provided it has more than epoxy group per molecule. Many are listed in the Specification. Conventional additives, e.g. pigments, other film-forming materials may be included. In Examples (1), (2), (4) a diimine from hexamethylene diamine and methyl isobutyl ketone is used together with moisture to cure a condensate from epichlorohydrin and bis-(4 hydroxyphenyl)-2, 21-propane. Curing may be at room temperature or in an oven with a humid atmosphere. If desired a condensate of ethylene or butylene glycol with epichloro hydrin may be used alone or together with the first condensate referred to. (3) The latent curing agent is prepared from methyl isobutyl ketone and ethylene diamine. (5) A diimine from methyl isobutyl ketone and xylylene diamine is used to cure the diglycidyl ether of butylene glycol. (6) A diimine from cyclohexanone and hexaethylene diamine or from methylethyl ketone and hexamethylene diamine is used to cure a diglycidyl ether condensate of bis- (4 hydroxyphenyl)-2, 2-propane. (7) A diimine from ethyl isopropyl ketone or methyl isopropyl ketone and tetramethylene diamine is used to cure a copolymer of glycidyl methacrylate and ethyl acrylate in a mono-n-butyl ether of diethylene glycol/ethyl acetate mixture. Specifications 518,057, 579,698, 595,447, 853,619, 905,725 and U.S.A. Specification 2,324,483, 2,444,333, 2,606,810, 2,607,754, 2,730,427, 2,752,269, 2,828,313 and 2,850,532 are referred to.