GB937412A - Esters containing epoxide groups, their production and their use - Google Patents

Abstract

Compounds of the formula <FORM:0937412/IV(a)/1> where n is 1 or 2, and Z is the residue of a carboxylic acid having n carboxyl groups, the said residue containing an epoxide group when n is 1 and optionally containing an epoxide group when n is 2 (see Group IV(b)) may be cross-linked or hardened by conventional hardeners for epoxide compounds. The hardeners may be acidic or basic, many being specified. The preferred hardeners are polybasic carboxylic acids and their anhydrides. Accelerators may also be present, such as tertiary amines or polyhydroxy compounds. Hardenable compositions comprise one or more esters of the above general formula together with one or more hardening agents and preferably also a proportion of an ester of the above general formula in which some or all of the epoxide groups are hydrolysed to hydroxyl groups, and/or contain other polyhydroxy compounds. Other epoxides may also be present in the compositions, as may fillers, plasticizers or colouring agents. In Example 3, a resin is formed by curing 3,4-epoxy-2,5-endomethylene-cyclohexyl-3, 4-epoxy- D 3-tetrahydrobenzoate with phthalic anhydride and benzyldimethylamine; the epoxidized ester may be stored in the form of an adduct with phthalic anhydride and subsequently cured by heating.ALSO:The invention comprises compounds of the formula <FORM:0937412/IV(a)/1> where n is 1 or 2, and Z is the residue of a carboxylic acid having n carboxyl groups, the said residue containing an epoxide group when n is 1 and optionally an epoxide group when n is 2. Preferred compounds are those of the general formula <FORM:0937412/IV(a)/2> wherein R1 and R2 are separately hydrogen or together represent an endomethylene group, and R3 represents a hydrogen atom or a methyl group, and those of the general formula <FORM:0937412/IV(a)/3> wherein A represents a divalent aliphatic, cycloaliphatic or aromatic residue which may be substituted by a hydroxyl group. The compounds are prepared by epoxidising a compound of formula <FORM:0937412/IV(a)/4> wherein n is 1 or 2, and Z1 stands for the residue of a carboxylic acid having n carboxyl groups, said residue containing an epoxidisable group when n is 1, and optionally containing an epoxidisable group when n is 2, the term "epoxidisable group" being defined in the Specification. The epoxidation may be carried out by treatment with per-acids and the reaction product may contain compounds in which some or all of the epoxide groups have been hydrolysed to hydroxyl groups. The esters which are to be epoxidised are prepared by esterification of dehydronoborneol with the corresponding acids or their anhydrides or acid chlorides, numerous acids, including halogen substituted acids, being specified. In Example (1) dehydroporborneol is esterified with succinic anhydride in the presence of xylene and toluene-p-sulphonic acid, and the product treated with peracetic acid to give bis-3,4-epoxy-2,5-endomethylene-cyclohexyl succinate. In further examples using a similar method dehydronorborneol gives: (2) bis-3,4-epoxy-2,5-endomethylene-cyclohexyl phthalate from phthalic anhydride; (3) 3,4-epoxy-2,5-endomethylene-cyclohexyl 3,4-epoxy-D 3-tetrahydrobenzoate from 1,2,5,6-tetrahydro-benzoic acid: (4) bis-3,4-epoxy- 2,5-endomethylenecyclohexyl 4,5-epoxy-D 4-tetrahydrophthalate from 1,2,3,6-tetrahydro-phthalic anhydride; (5) 3,4-epoxy-2,5-endomethylene-cyclohexyl 3,4-epoxy-2,5-endomethylene-D 3-tetrahydrobenzoate from 2,5-endomethylene- 1,2,5,6-tetrahydro-benzoic acid; (6) 3,4-epoxy-2,5-endomethylene-cyclohexyl 9,10-epoxy-octadecanoate from oleic acid; (7) 3,4-epoxy-2,5-endomethylene-cyclohexyl 6-methyl-3,4-epoxy-2,5-endomethylene-D 3-tetrahydrobenzoate from 6-methyl-2,5-endomethylene- D 3-tetrahydrobenzoic acid. The Provisional Specification refers to epoxidised esters derived from alcohols other than dehydronorborneol in which the hydrogen atoms of dehydronorborneol may be replaced by monovalent substituents such as halogen atoms, alkoxy groups and aliphatic, cycloaliphatic, araliphatic or aromatic hydrocarbon residues, and the endomethylene group may be any divalent group, and to mixed esters of the polybasic acids with more than one of such alcohols. The products may be treated with acidic or basic hardeners to give resins (see Group IV(a)). The epoxidised ester prepared in Example 3 forms an adduct with phthalic anhydride.