Verfahren zur Herstellung von waermehaertbaren Harzen

摘要

Heat hardenable epoxy resins are prepared by polymerizing in presence of acid catalyst 3,4-epoxycyclohexyl-methyl 3,4-epoxycyclohexane carboxylates of formula wherein R1-R6 are H or alkyl groups. Catalysts specified are boron trifluoride, stannic chloride, zinc chloride, aluminium chloride, ferric chloride; etherates and aminates of boron trifluoride; sulphuric, phosphoric, perchloric, polyphosphoric and aromatic sulphonic acids. The carboxylates are prepared by epoxidizing by treatment with peracetic acid &c. the corresponding 3-cyclohexenyl-methyl-3-cyclohexene-carboxylates, as described in Specification 768,157, [Group IV (b)]. The epoxy compounds are heated in presence of the catalyst at 50-160 DEG C. to form a gel which is then cured by heating at 100-150 DEG C. for a time ranging from 30 mins. to 10 hours according to the temperature, catalyst and amount of catalyst used. In examples: (5) 1.4 gs. 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexane-carboxylate and four drops of a 10 per cent solution of stannic chloride in ethyl acetate were mixed and placed in an oven heated to 110 DEG C. The mixture gelled in 5 minutes and on further heating at 110 DEG C. for 20 hours cured to a colourless transparent resin with a Barcol hardness of 37; (6) the compound of Example (5) was polymerized in presence of sulphuric acid. It is stated that the monomeric diepoxides can be polymerized and copolymerized with polycarboxylic acids, polyols, amines, epoxides, &c. Reference has been directed by the Comptroller to Specification 768,157.ALSO:3,4-Epoxycyclohexylmethyl 3,4-epoxy-cyclohexanecarboxylates of formula wherein R1-R6 are H or alkyl groups are prepared by (a) reacting 3-cyclohexenecarboxyaldehydes in presence of an aluminium alkoxide catalyst dissolved in an inert solvent, e.g. benzene at 0 DEG to 110 DEG C. to obtain 3-cyclohexenylmethyl 3 - cyclohexenecarboxylates and (b) epoxidizing the latter compounds by treatment with peracetic acid as described in Specification 768,157. Typical 3-cyclohexenecarboxyaldehydes which may be used as starting materials are 3-cyclohexenecarboxyaldehyde, 2,4 - dimethyl - 3 - cyclohexenecarboxyaldehyde, 3,4 - dimethyl - 3 - cyclohexenecarboxyaldehyde, 2-, 3-, or 4-methyl-3-cyclohexenecarboxyaldehyde, 2,2,5,5 - tetramethyl-, 2,2 - dimethyl - 5 - methyl-, 2,2 - dimethyl - 4 - methyl-, 3- or 4-methyl - 6,6 - dimethyl-, 3- or 4 - methyl - 6 - methyl, 3- or 4-methyl-6-ethyl-, 1-methyl-3- or 4-methyl-6-ethyl-, 2,2,6-, 2,4,6-, 2,5,6-, 2,2,4-, 2,2,5-, 3,6,6-, 4,6,6 - trimethyl, 2,2,5,5,6-pentamethyl - 3 - cyclohexenecarboxyaldehydes, 2,2,5,6- (or 1) - tetramethyl - 3 - cyclohexene-1 (or 6)-carboxyaldehyde, 2,2,4,6- (or 1)-tetramethyl - 3 - cyclohexene - 1 (or 6)-carboxyaldehyde. In examples: (1) 20 mols. 3-cyclohexenecarboxyaldehyde are added dropwise to a flask containing 0.5 mol. aluminium isopropoxide dissolved in 900 gs. benzene maintained at 20-25 DEG C. The mixture is left to stand for 16 hours and then 83 ml. conc. HCl is added, the aqueous layer is separated and the organic layer distilled to obtain 3-cyclohexenylmethyl-3-cyclohexenecarboxylate; 6-methyl-3-cyclohexenylmethyl 6 - methyl - 3 - cyclohexenecarboxylate is obtained from 6-methyl-3-cyclohexenecarboxyaldehyde in a similar way; (3) the cyclohexenecarboxylate is epoxidized by addition thereto dropwise of a 25.5 per cent solution of peracetic acid in acetone, the solution being maintained at 20-25 DEG C. during the reaction and afterwards for 16 hours at -11 DEG C.; (4) describes a similar method for the preparation of 3,4-epoxy-6-methylcyclohexylmethyl-3,4 - epoxy 6 - methylcyclohexanecarboxylate. Reference has been directed by the Comptroller to Specification 768,157.