GB555520A - Improvements in or relating to thermoplastic compositions and process for preparing the same - Google Patents

Abstract

555,520. Resins. HERCULES POWDER CO. March 19, 1942, No. 3672. Convention date, Nov. 7, 1941. [Class 95] [Also in Group IV] A composition suitable for use as a substitute for shellac comprises about 60-80 per cent by weight of pine-wood resin which is substantially insoluble in petroleum hydrocarbons, about 10- 30 per cent. of ethyl cellulose, and 5-30 per cent. of a plasticizing agent. The resin may be obtained by subjecting pinewood, preferably stump pine-wood, if desired after steaming to remove turpentine, pine oil, and other volatile constituents, to extraction with a coal tar hydrocarbon such as benzene or toluene, freeing the extract from volatile constituents, and extracting wood resin from the residue by means of a petroleum hydrocarbon such as gasoline, thus leaving a resin having a low abietic acid content. Alternatively, the residue of the initial coal tar hydrocarbon extract may be treated with a mixture of petroleum hydrocarbon and furfural, and the two layers then separated. The furfural layer is taken and the furfural is removed by evaporation leaving the desired resin. This resin is insoluble in petroleum hydrocarbons, and completely soluble in alcohol. It has a methoxy content of about 3-7.5 per cent., acid number 80-110, and a drop melting point of 95-125‹ C. The ethyl cellulose used is of the type soluble in organic solvents and of ethoxyl content 41-51 per cent. It may have high or low viscosity characteristics. The plasticizer may bean aryl phosphate, e.g. diphenyl mono- (oxenyl) phosphate, a halogenated hydrocarbon, e.g. chlorinated diphenyl, a phtbalic acid, ester, e.g. ethyl phthalyl ethyl glycolate, a glyceride, e.g. castor oil, coconut oil, or tripropionin, or butyl acetyl ricinoleate, methyl abietate, o- or ptoluene sulphonamide. The ingredients of the composition may be mixed with the aid of heat or solvents, e.g. acetone. The composition may be dissolved in methanol, ethanol, benzene, or toluene to form a spirit varnish, or it may be used in molten state to coat or impregnate cloth or paper or to form an electrical insulating medium. It may be used as a moulding composition and may be used for making phonograph records. Ingredients such as cellulose fillers, clay, slate, silica, carbon black, marble flour, zinc oxide, and mould lubricants such as vegetable and mineral waxes, Stearic acid, magnesium steacate, and zinc stearate may be incorporated in the composition. The composition may be mixed with shellac if desired.