Patent GB-595104-A (GB)
Title: Improvements in or relating to the preparation of mixed esters
Filed: 1945-07-02
Abstract: Synthetic varnishes are prepared by heating a resinous compound having a carboxyl group in the molecule with a short chain monobasic acid having a chain of up to twelve carbon atoms and two to four conjugated double bonds, one of these being in conjugation with the carboxyl group, (excluding any such materials as may be derived from naturally occuring drying oils) and with (a) a polyhydric alcohol and a monobasic fatty acid derived from a naturally-occuring drying oil, or (b) a polyhydric alcohol and a glyceride or other polyhydric alcohol ester of a monobasic fatty acid derived from a naturally occurring drying oil, or (c) a glyceride or other polyhydric alcohol ester of a monobasic fatty acid derived from a naturally occurring drying oil.  The substances under (a) and (b) may be wholly or partly reacted together before adding to the other reactants.  Resinous compounds specified are: rosin, dimerised rosin, reaction products of hydroxyaromatic acids, e.g. p-hydroxybenzoic acid and its homologues, with aldehydes, e.g. formaldehyde, and ketones, e.g. acetone, maleic acid adducts, e.g. of rosin, cyclopentadiene, or terpenes, or their partial esters, partially esterified alkyd resins prepared from polyhydric alcohols and polybasic acids, such as phthalic, maleic, succinic, or their anhydrides with or without a monobasic fatty acid. Polyhydric alcohols specified are glycols, polyglycols, glycerols, polyglycerols, pentaerythritol, mannitol.  Monobasic fatty acids may be those having 12 to 22 carbon atoms and include lauric, myristic, palmitic, stearic, linoleic, linolenic, oleic, eleostearic, licanic, ricinoleic, and clupanodonic acids, which occur in tung, linseed, castor, dehydrated castor, soya, isomerised soya, perilla, and other vegetable and fish oils; mono-, di-, and triglycerides of these acids may be employed.  Short-chain acids specified are: vinylacrylic, sorbic, octatrienoic, decatetrenoic, styrylacrylic, b -methylsorbic, b -ethylsorbic, b d -dimethylsorbic, g e -dimethylsorbic, a -methyl-d -phenyl butadiene carboxylic, a -ethyl-d -phenyl-butadiene carboxylic, dimethyl-octadienoic, dimethyl-decatrienoic, di-isopropylidene propionic, vinyl cinnamic, isopropenyl-cinnamic, isopropenyl-furfural-acetic, isopropenyl-cinnamenyl-acrylic.  In examples: (1) rosin, pentaerythritol, and linseed oil fatty acids are heated in an atmosphere of carbon dioxide with sorbic, styryl-acrylic, a -vinylcinnamic and octatrienoic acids; (2) sorbic acid, glycerol, and linseed oil fatty acids are heated with a resin from p-hydroxybenzoic acid and formaldehyde, and with a partially esterified alkyd resin prepared from phthalic anhydride, glycerine and linseed oil acids; (3) sorbic acid, linseed oil acids, dimerised rosin, and pentaerythritol are heated; (4) sorbic acid, rosin-maleic adduct, and linseed diglyceride are heated. The products may be mixed with cobalt and lead naphthenate driers and/or petroleum spirit.  A p-Hydroxybenzoic acid-formaldehyde resin is prepared by heating the ingredient with oxalic acid as catalyst and heating with rosin.