GB417937A - Improvements in or relating to the production of plastic materials - Google Patents

Abstract

In the production of a plastic composition, a solution of plasticizer or softening agent in the presence of the solid plasticizable substance is treated so that the solvent power of the liquid in which the plasticizer is dissolved, is diminished. The process may be applied to the preparation of compositions of cellulose esters and ethers or synthetic resins such as cellulose acetate, nitrate, butyrate, laurate, or naphthenate, or ethyl or benzyl cellulose, or polymerized vinyl compounds. The compositions may be used in the form of doughs or moulding powders and made into films, rods, tubes, blocks, or other articles. The solvent power of the liquid for the plasticizer may be diminished by addition of a liquid of low or non-solvent power for the plasticizer, or if the liquid comprises a mixture of volatile solvent and less volatile non-solvent the result may be obtained by evaporation. Methyl or ethyl alcohol or acetone-alcohol mixtures may be used as solvents for the plasticizer, and water added to diminish the solvent power. In an example, cellulose acetate in powder form is stirred with xylene monomethyl sulphonamide in alcohol and water is slowly added so as to transfer the plasticizer to the cellulose acetate. The solution of plasticizer in alcohol may be stirred into a suspension of cellulose acetate in water. Diphenylol propane or an aromatic phosphate may be used as plasticizer for polyvinyl compounds. The plastic compositions may contain pigments, fillers, dyes, resins, stabilizers, and substances for reducing inflammability. The latter may be mineral phosphates, halogenated phenols, halogenated aromatic amines, and their acidyl derivatives. Dicyandiamide or other agents may be added to remove any free halogen resulting from decomposition of the fireproofing agent. Specification 319,073, [Class 2 (ii)], is referred to.ALSO:In the production of a plastic composition, a solution of plasticizer or softener in the presence of the solid plasticizable substance is treated so that the solvent power of the liquid in which the plasticizer is dissolved, is diminished. The process may be applied to the preparation of compositions of synthetic resins such as polyvinyl compounds. The compositions may be used as doughs or powders in the formation of films, tubes, rods, blocks, or other articles. The solvent power of the liquid for the plasticizer may be reduced by addition of a low or non-solvent liquid, or if the liquid comprises a mixture of volatile solvent and less volatile non-solvent, by evaporation. Alcohol, or acetone-alcohol mixtures may be used as solvents for the plasticizer, and water may be added to diminish the solvent power. The powdered substance to be plasticized may be stirred up with an alcoholic solution of plasticizer and water slowly added. The alcoholic solution of plasticizer may be stirred into a suspension of the plasticisable substance in water. Diphenylol propane or an aromatic phosphate may be used as plasticizer for polyvinyl compounds. Pigments, fillers, dyes, tabilizers, and fireproofing agents may be added. The latter may be mineral phosphates, halogenated phenols, halogenated aromatic amines, and their acidyl derivatives. Dicyandiamide or other agents may be added to absorb free halogen. Specification 319,073, [Class 2 (ii)], is referred to.