Patent GB-967351-A (GB)
Title: Improvements in and relating to the preparation of boron trifluoride-oxime complexes and the use of such complexes as hardeners for synthetic resins
IPC: C08G59/72
Filed: 1962-11-16
Abstract: Boron trifluoride-oxime complexes are made by dissolving an oxime or ether thereof of the formula R1.C(R2)=N-OR3 where each of R1 and R2 is a monovalent aliphatic, cycloaliphatic, aromatic, araliphatic or heterocyclic radical, or a hydrogen atom and R1 and R2 are the same or different, or where R1.C(R2)= is a divalent cycloaliphatic or heterocyclic radical, and where R3 is a hydrogen atom or a monovalent organic radical, in boron trifluoride diethyl etherate, if necessary at an elevated temperature, and removing the solvent therefrom, if necessary after cooling the solution. The oxime or ether may be derived from acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, cyclohexanone, furfural, acetaldehyde and benzaldehyde. Detailed examples are given. The complexes are used as hardeners for epoxy resins. Solutions of the BF3-oxime complexes in an alcohol or a mono or polyether containing at least one free hydroxyl group or in a mixture of two or more of said solvents are preferred.ALSO:Epoxy resins are hardened using a boron trifluoride-oxime complex derived from an oxime or ether thereof of the formula R1-C(R2)=N-OR3 where each of R1 and R2 is a monovalent aliphatic, cycloaliphatic, aromatic, araliphatic or heterocyclic radical, or a hydrogen atom, and R1 and R2 are the same or different, or where R1-C(R2)=is a divalent cycloaliphatic or heterocyclic radical, and R3 is a hydrogen atom or a monovalent organic radical, by reaction with a boron trifluoride diethyl etherate. The BF3-oxime complexes may be used in solution in an alcohol or a mono- or poly-ether containing at least one free hydroxyl group, or mixtures of two or more of these solvents.  Conventional amine hardeners such as alkylol-amine, diamine, triamine, polyamine or polyamide may be used as accelerators.  Suitable epoxy resins are diglycidyl and polyglycidyl esters, epoxidized diolefins, dienes or cyclic dienes, diolefin-unsaturated carboxylic esters and carboxylic esters containing two cyclohexenyl radicals, glycidyl polyethers of divalent or polyvalent alcohols or phenols or basic polyepoxides derived from aromatic amines and epichlorhydrin. Particularly suitable are epoxy resins made from bis(4-oxyphenyl) 2,2-propane. Mixtures of liquid or solid epoxy resins in solution with the BF3-oxime hardeners may be used for the preparation of casting resins, protective coatings, laminating resins and adhesives.  They may contain fillers such as powdered quartz, ground shale, chalk, alumina minerals, graphite, and also pigments, softeners or solvents.  In examples, a liquid epoxy resin made by alkaline condensation of bis(4-oxyphenyl)-2,2-propane with epichlorhydrin is hardened (3) with BF3-acetoxime complex in diethylene glycol; (4) as in (3) after addition of fat alcohol glycidyl ether; (5) as in (3) and (4) with ethylene glycol monallyl ether as solvent; (7) with BF3-benzophenone oxime and polyethylene glycol monoethyl ether; (8) BF3-cyclohexanone oxime and diethylene glycol; (9) BF3-furfuraldoxime in diethylene glycol; (10) BF3-aldoxime and diethylene glycol monoethyl ether; (11) after dilution with fat alcohol glycidyl ether and phenylglycidyl ether with a polyamide and BF3-acetoxime in ethylene glycol; (12) after dilution as in (12) with diethylene triamine and BF3-acetoxime in ethylene glycol; (13) as in (12) using a cycloaliphatic diamine as co-hardener.