GB767829A - Epoxide-containing ester adhesives, and a process for gluing together materials - Google Patents

Abstract

Adhesive compositions contain a 1,2-epoxy-alkyl ester of an aromatic polycarboxylic acid mixed with an acidic substance. The epoxyalkyl esters may be prepared by the methods of Specifications 735,001 and 766,771. The aromatic polycarboxylic acid may be a polyester prepared from glycol or glycerine with excess of an aromatic polycarboxylic acid. The acidic substance may be an inorganic or organic acid, acid chloride, anhydride or acid salt, or a phenol. A list of suitable substances is given in the Specification. The esters may be partially condensed before use by heating alone or in presence of an epoxy resin curing agent, e.g. piperidine or phthalic anhydride. Glycidyl esters of carboxyl-containing polyesters may also be employed. Non-acid catalysts, e.g. cyanamide, dicyandiamide, melamine, acetamide or adipic acid diamide may also be included in the compositions. Plasticisers, e.g. dibutylphthalate or tricresylphosphate, and other epoxy compounds, e.g. glycidyl ethers of polyhydric phenols, phenyl glycidyl ether, glycidyl esters of fatty acids, epoxidised drying oils, butadiene epoxides or glycide may also be added. The esters may be used in solution, in volatile solvents, e.g. ethers or ketones, as powders to be melted or on sheets, e.g. of paper or fabric. One part of the composition may be applied to one surface to be stuck and the remainder to the other. Hardening is preferably effected at raised temperature. Fillers, e.g. wood meal, mica, stone dust, and other adhesives, e.g. animal glue, starch derivatives, cellulose derivatives, phenylformaldehyde resins, urea or melamine resin may be added to the adhesives. The adhesives may be used for all combinations of material, as binders for moulded articles or for laminating sheets of all kinds. In many of the examples: a resin prepared from dipotassium phthalate and epichlorhydrin is used as an adhesive together with phthalic anhydride, maleic anhydride, mixtures of maleic and adipic anhydrides, o-phenylcyclophosphoric acid, monobutylorthophosphoric acid, b ,b -(4-hydroxyphenyl)-propane, resorcinol, p-toluene-sulphonic acid or terephthalic acid dichloride. In some cases the resin is first reacted to a limited extent with maleic anhydride, phthalic anhydride, or piperidine. In other examples, there is also present in the adhesive compositions: a linseed oil-maleic acid adduct, a copolymer of 2-methylol-2-chloromethyl - oxacyclobutane and 2 - methylol, 2-ethoxymethyl oxacyclobutane, 2,6 - dioxa - 3,3 - spiroheptane, tricresylphosphate, dibutylphthalate, or acetone or dioxane as a solvent. Other examples describe the use of the adhesives to impregnate paper for use in laminating beech veneers, or the formation of a hard brittle resin which either in powder form or as an extruded piece may be used for adhesion. Still other examples describe the use of resins either from terephthalic acid dichloride and glycide in presence of triethylamine, or from dipotassium terephthalate and glycide. Reference has been directed by the Comptroller to Specifications 518,057, [Group IV], and 723,777.ALSO:Epoxyalkyl esters of aromatic polycarboxylic acids are formed from epichlorhydrin and the alkali metal salt of the acid or from glycide and the acid chloride or anhydride. In examples: (1) finely powdered dipotassium phthalate and epichlorhydrin are reacted in an autoclave at 50 atmospheres pressure of nitrogen and 140-150 DEG C. Salt is filtered off and washed with epichlorhydrin. The filtrate is distilled and the epoxy ester (average mol. weight 442) remains; (14) terephthalic acid dichloride, glycide and triethylamine are mixed in toluene with cooling. Triethylamine hydrochloride is removed by filtration and the epoxy ester (mol. weight 480) remains as residue after distillation of the filtrate; (22) glycide is reacted with a mixture of phthalic acid anhydride and adipic acid anhydride. Specifications 735,001 and 766,771 are referred to. Reference has been directed by the Comptroller to Specifications 518,057, [Group IV], and 723,777.