GB1022252A - Improvements in and relating to resins - Google Patents

Abstract

Alkali-soluble resins suitable for coating compositions are obtained by (a) reacting a drying or semi-drying oil with sufficient maleic anhydride or maleic, fumaric or itaconic acid to give a product soluble in aqueous alkali; (b) reacting the product with a phenol; and (c) reacting the product of (b) with an aldehyde. Specified reactants are:-drying oils cottonseed, soybean, corn, oiticia, tung, linseed and pirella oils; phenols phenol, cresol, resorcinol, catechol and alkylphenols; aldehydes formaldeydehyde and acetaldehyde. Each step is preferably conducted in an inert atmosphere. A suitable catalyst for step (b) is oleum. In the specific example the catalyst for step (c) is ammonia. The final product may be dissolved or dispersed in aqueous ammonia or a volatile organic base such as methylamine or morpholine, optionally with filler and pigments to give a coating composition. In the specific example a resin is prepared from tung oil, maleic anhydride, phenol and formaldehyde and a solution thereof in diethylaminoethanol is mixed with a dispersion of red iron oxide and is painted on to steel panels to give after heating at 160 DEG C. for 30 minutes, a hard flexible coating resistant to hot water and salt water spray.ALSO:Steel panels are coated with a composition containing an alkali-soluble resin obtained by (a) reacting a drying or semi-drying oil with sufficient maleic anhydride or maleic, fumaric or itaconic acid to give a product soluble in aqueous alkali; (b) reacting the product with a phenol; and (c) reacting the product of (b) with an aldehyde. Specified reactants are: drying oils cottonseed, soybean, corn, oiticia, tung, linseed and pirella oils; phenols phenol, cresol, resorcinol, catechol and alkylphenols; aldehydes formaldehyde and acetaldehyde. Each step is preferably conducted in an inert atmosphere. A suitable catalyst for step (b) is oleum. In the specific example the catalyst for step (c) is ammonia. The final product may be dissolved or dispersed in aqueous ammonia or a volatile organic base such as methylamine or morpholine, optionally with filler and pigments to give a coating composition. In the specific example a resin is prepared from tung oil, maleic anhydride, phenol and formaldehyde and a solution thereof in diethylamino-ethanol is mixed with a dispersion of red iron oxide and is painted on to steel panels to give after heating at 160 DEG C. for 30 minutes, a hard flexible coating resistant to hot water and salt water spray.