Improvements in or relating to alkyd resins

Abstract

Abstract Fast-drying resinous products are prepared by heating together glycerol phthalic anhydride, hydroxyacetic acid and linseed oil or linseed oil fatty acids in such proportions that the product contains when expressed in terms of those ingredients 30-70 per cent of linseed oil and a weight ratio of polyhydroxyacetic acid to glyceryl phthalate below 0.7 and not below 0.1. Modifying agents which may be used in addition to linseed oil are soya, chinawood, cottonseed, oiticica, perilla, castor, dehydrated castor, coconut, sunflower seed or corn oil or the fatty acids from these oils, butyric, stearic, acrylic, furacrylic, oleic, p lactic, chloracetic, benzoic, salicylic or rosin acid, or butyl, n-dodecyl, benzyl, or cyclohexyl alcohol. Excess glycol may be used to increase drying rates. The reactants may be mixed in any suitable order. Fatty oils should be heated with all or part of the polyhydric alcohol before addition of the acid components. The hydroxyacetic acid may be used as a water solution. The preferred temperature range is 150-250 DEG C. Various catalysts, e.g. litharge, sodium hydroxide or acids may be employed. Certain acid salts, e.g. monosodium phosphate improve the colour of the resins. The reaction may be performed in solution, e.g. in a hydrocarbon or in the absence of solvent. The resins are useful as vehicles for air drying or baking compositions which may also include pigments, metallic driers, dyes, fillers, waxes, inhibitors, plasticisers or thinners, and other film-forming ingredients, e.g. cellulose derivatives, rubber derivatives, urea-formaldehyde resins, phenol-formaldehyde resins, other alkyd resins, rosin, ester gum, limed rosin, polymethyl methacrylate, polystyrene, or polyvinyl acetate. The resins can also be used as adhesives or moulding compositions or as grinding vehicles or in the incorporation of hydrophyllic extenders in pigment formulations. Examples describe (1) preparation of a resin from linseed oil acids, glycerol, phthalic anhydride, and hydroxyacetic acid by heating in an atmosphere of carbon dioxide with addition of toluene and removal of water and some toluene. The product is dissolved in a mixture of low-flash naphtha and mineral spirits. Incorporation of cobalt, lead or manganese naphthenate gave a solution which was air dried tack-free in 5-7 hours and gave tough films after baking for two hours at 140 DEG C. (2) Similar to (1), the linseed oil acids and glycerol being reacted before addition of the other ingredients and hi-flash naphtha being the reaction medium. Four other examples describe similar preparations with differences of detail. Example (4) describes the blending of the hydrocarbon solution of resin with a standard toluidine red mill base and preparation of films from the mixture. Comparative figures are given for the drying rates of resins prepared according to the invention and prepared from mixtures of the same reaction ingredients in different proportions.

Inventors

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