Syntheis and Application of New Raw Materials of Resins for Paint Industry. VI.

Polyether Resins of Oxacyclobutane

Abstract

Polyether resins with pendant hydroxyl groups were prepared by copolymerization of 3-chloromethyl-3-hydroxymethyloxacyclobutane (CHMO) with various substituted oxacyclobutanes, cyclic ethers and alkyl glycidyl ester of carboxylic acid (AGE) in the presence of cationic catalysts such as boron trifluoride-etherate. The polyether resins thus prepared can be esterified with fatty acids, or can be cured with melamine-formaldehyde resin.
A typical preparative procedure is described in the following. Boron trifluoride-etherate (0.2 mole %) was added to the dry xylene solution of CHMO (1 mole), various substituted oxacyclobutanes or cyclic ethers at 0-2°C. The solution was kept at room temperature for 3 hrs., refluxed for 2-3 hrs., and then methanol was added. The product copolymer was isolated by decantation or vacuum distillation. The yield was 97-100%. The hydroxyl value and chlorine content of the product resins were in good agreement with those expected from the monomer composition.
The copolymer of CHMO with the substituted oxacyclobutane was a pale-yellow liquid, soluble in alcohols, ketones, cellosolves, dimethylformamide and dioxane. The copolymer of CHMO with the cyclic ether was soluble in most of the organic solvents.
White enamels were prepared by blending the polyether resin with a melamine-formaldehyde resin in the ratio of 9 : 1 to 6 : 4 at the PWC of 40%. The enamel was applied on steel panels and baked at 120-480°C for 20-30 min. The film derived from CHMO and the substituted oxacyclobutane was superior in thermal stability and hardness to those of the commonly used resins, but poor in water resistance and chemical properties. The cyclic ethers, especially tetrahydrofurane (THF) and AGE, were found to be a good plasticizing ingredient. The film derived from CHMO, the substituted oxacyclobutane and THF or AGE proved to be excellent not only in gloss but in chemical and mechanical properties which were comparable to those of the epoxy resins. and acrylic resins.