Societa' Italiana Resine S.i.r. S.p.a.

Euteco, S.p.a.

Giancarlo Crespolini

Silvio Vargiu

Mario Pitzalis

Giulio Grazzini

Edoardo Carpaneti

Gino Giuliani

A liquid epoxy resin is produced by gradually feeding an aqueous solution of alkali metal hydroxide into a solution of bisphenol-A in epichlorohydrin, while maintaining the reaction medium at boiling point, distilling off water in the form of an azeotrope with epichlorohydrin and recycling the latter, and maintaining a water content of from 0.1 to 0.7 wt.% and a pH value between 7 and 9 in said reaction medium. The liquid epoxy resins thus obtained have low values of the viscosity, epoxy equivalent and hydrolyzable chlorine content.

Preparation of liquid epoxy resins from bisphenols

Petroleum resins are prepared by subjecting to pre-polymerization a hydrocarbon fraction containing olefins and diolefins, having a boiling range of from 30.degree. to 300.degree. C, in the presence of activated clays, recovering from the pre-polymerization products a selected hydrocarbon fraction having a boiling point not exceeding 250.degree. C, mixing this selected fraction with a hydrocarbon fraction containing unsaturated hydrocarbons with an average of 5 carbon atoms per molecule, subjecting the resulting mixture to polymerization in the presence of a Friedel-Crafts catalyst and recovering the petroleum resins from the polymerization products. These petroleum resins form homogeneous mixtures with rubber.

Process for the preparation of petroleum resins

Diepoxides of the general formula: ##STR1## wherein n has an average value not exceeding 0.03 and R is the bisphenyl radical of bisphenol-A are recovered from an epoxy resin of the same general formula with n varying from 0.07 to 0.30, by removing the low-boiling substance from the epoxy resin at 0.1-1 mm Hg and 165.degree.-200.degree. C and distilling off said diepoxide from the thus treated epoxy resin at 0.1-0.005 mm Hg and a temperature not exceeding 240.degree. C. The low viscosity, narrow molecular weight distribution and excellent purity of these diepoxides allow their use in critical application fields.

Process for the preparation of diepoxides

Liquid epoxy resins are produced by contacting a dihydroxy phenol with an excess of epihalohydrin and an aqueous solution of an alkali metal hydroxide in a molar ratio of hydroxide to phenol not exceeding 2:1, recovering from the reaction products an epoxy resin having a content of hydrolyzable chlorine of from 1 to 6% by weight, contacting a solution of the resin in a hydrocarbon with an aqueous solution of an alkali metal hydroxide while maintaining an atomic ratio of alkali metal to hydrolyzable chlorine contained in the resin of from 1:1 to 1.17:1 and recovering from the reaction products a liquid epoxy resin having a content of hydrolyzable chlorine less than 0.02% by weight. These epoxy resins of high purity are particularly useful as varnishes or coatings.

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Bergamo, Italy

Giancarlo Crespolini