Patent GB-407050-A (GB)
Title: Improvements in or relating to plastic materials
IPC: C08F8/00
Filed: 1932-09-09
Abstract: Lacquers, varnishes and enamels are manufactured by dissolving in organic solvents the products obtained by reacting a polyvinyl ester in solution with ethylidene diacetate in the presence of a substantially anhydrous alcohol and an acid catalyst.  In an example, polyvinyl acetate of molecular weight about 13,000 (by Standinger's method) is heated with ethylidene diacetate, methanol and a solution of hydrogen chloride in methanol, the thin solution obtained is diluted with a mixture of toluene and the acetate of glycol monoethyl ether, and dibutyl phthalate is added, producing a clear lacquer suitable for spraying.ALSO:Plastic materials are manufactured by reacting a polyvinyl ester in solution with ethylidene diacetate in the presence of a substantially anhydrous alcohol and an acid catalyst, e.g. hydrogen chloride.  The viscosity and solubility of the product can be varied by varying the degree of polymerization of the initial polyvinyl ester, less viscous products suitable for coating and impregnating compositions, in which the resin is dissolved in organic solvents, being obtained from the polyvinyl esters of the lower degree of polymerization.  If the quantity of ethylidene diacetate used is less than that theoretically required for complete replacement of the ester group of the polyvinyl ester, the products obtained even from low polymerized esters form jellies or much more viscous solutions than those obtained with theoretical quantities of ethylidene diacetate.  The extent to which the softening point of the products is raised above that of the parent polyvinyl esters depends on the amount and nature of the acid catalyst, the duration of heating, the nature of the polyvinyl ester employed, the nature of the alcohol employed and the amount of ethylidene diacetate used.  The reaction may be carried out by heating at normal or increased pressure and the products may be isolated from the reaction mixture by removing the volatile constituents by evaporation under normal or reduced pressure or by precipitating the resin with water.  The products may be bleached, e.g. by means of sodium hydrosolphite.  They may be dissolved in organic solvents to produce lacquers, varnishes and enamels, and may also be used as substitutes for shellac, e.g. in the manufacture of gramophone record discs or cylinders, and also for the manufacture of moulded objects, e.g. by the injection moulding process, if desired with the addition of plasticizing agents, e.g. dibutyl phthalate. They may also be mixed, if desired with the aid of volatile solvents, with other resins (synthetic or natural), e.g. aldehyde resins or gum copal, with cellulose esters or ethers, e.g. nitrocellulose, cellulose acetate, ethyl or benzyl cellulose, with softening agents or oils, with filling materials, e.g. silica, barium sulphate, wood meal or cork dust, with colouring matter, e.g. carbon black or coal tar dyes, or with mixtures of these substances.  In examples: (1) polyvinyl acetate of molecular weight about 30,000 (by Staudinger's method), obtained by polymerizing vinyl acetate by means of benzoyl peroxide, is heated in a closed vessel with ethylidene diacetate, absolute alcohol and a saturated solution of hydrogen chloride in absolute alcohol, and the product is precipitated by adding water; if the reaction mixture is left to stand without precipitating the resin, it sets to a jelly; (2) methyl alcohol is used in place of absolute alcohol, and p-toluenesulphonic acid as catalyst; (3) n-propyl alcohol and ethanesulphonic acid are employed; (4) polyvinyl acetate of molecular weight about 13,000 is heated with ethylidene diacetate, methanol and a solution of hydrogen chloride in methanol, the thin solution obtained is diluted with a mixture of toluene and the acetate of glycol monoethyl ether, and dibutyl phthalate is added, producing a clear lacquer suitable for spraying; (5) as in (4) but using less ethylidene diacetate, the product setting to a jelly.ALSO:Plastic materials, obtained by reacting a polyvinyl ester in solution with ethylidene diacetate in the presence of a substantially anhydrous alcohol and an acid catalyst, may be mixed with plasticizing agents, e.g. dibutyl phthalate, and also, if desired with the aid of volatile solvents, with other resins (synthetic or natural), e.g. aldehyde resins or gum copal, with cellulose esters or ethers, e.g. nitrocellulose, cellulose acetate, ethyl or benzyl cellulose, with softening agents or oils, with filling materials, e.g. silica, barium sulphate, wood meal or cork dust, with colouring matter, e.g. carbon black or coal tar dyes, or with mixtures of these substances.