Patent GB-428456-A (GB)
Title: Improvements in or relating to the manufacture of thermoplastic compositions and articles comprising them
IPC: C08L1/12
Filed: 1933-11-06
Abstract: Thermoplastic compositions are formed by grinding a base material such as cellulose ester or ether, vinyl ester, rubber, chlorinated rubber, &c., with a non-solvent between closely spaced rapidly moving abrasive surfaces so as to form a paste or slurry. A suitable apparatus is a colloid mill comprising two discs with relative motion of 2500--5000 r.p.m. and faced with carborundum, corundum, fritted glass, emery, roughened steel, &c.  Smooth or grooved surfaces are not suitable.  Compositions of incompatible substances such as a cellulose derivative and rubber may be made by treating them together with a liquid which is a non-solvent for both.  Pigments, dyes, fillers, &c. may be ground with the thermoplastic substance. Plasticizers &c. may be similarly incorporated or may be added in the form of solutions to the dispersion.  The dispersions may be used, if necessary after the removal of a part or all of the non-solvent, for the production of moulding powders, plastic compositions, films, coating-compositions, impregnated and coated fabrics, paper, &c. Firmly adhering coatings on metal &c. are obtained by applying the dispersion or the product obtained by drying it to the surface and consolidating by heat and pressure.  In a typical example of the invention, 100 parts of cellulose acetate, 75 parts of asbestos, 25 parts of rubber, and 35 parts of plasticizers are dispersed in 500 parts of water.  The product after drying is a moulding powder suitable for the manufacture of insulators.ALSO:Thermoplastic compositions are formed by grinding a base material such as cellulose ester or ether, vinyl ester, rubber, chlorinated rubber, resin, &c. with a non-solvent between closely spaced rapidly moving abrasive surfaces so as to form a paste or slurry.  A suitable apparatus is a colloid mill comprising a stationary disc and a disc rotating at 2500--5000 r.p.m., the discs being faced with carborundum, corundum, fritted glass, emery, roughened steel, &c.  Smooth or grooved grinding surfaces are not suitable.  Compositions of incompatible substances, such as a cellulose derivative and rubber may be made by treating them together with a liquid which is a non-solvent for both. Pigments, dyes, fillers, &c. may be ground with the thermoplastic substance.  Plasticizers &c. may be similarly incorporated or may be added in the form of solutions to the dispersion.  The dispersions may be used, if necessary after the removal of a part or all of the non-solvent, for the production of moulding powders, plastic compositions, films, coating-compositions, impregnated and coated fabrics, paper, &c.  Firmly-adhering coatings on metal, glass, and other non-porous materials are obtained by applying the dispersion or the product obtained by drying it to the surface and consolidating by heat and pressure.  The following examples are typical of the invention.  (1) 100 parts of cellulose acetate, 75 parts of asbestos, 25 parts of rubber, and 35 parts of plasticizing agents are dispersed in 500 parts of water.  The product after drying is a moulding powder suitable for making insulators.  (2) 10 parts of chlorinated rubber, 1 part of tricresyl phosphate, and enough nigrosine for colouring purposes are dispersed in 20 parts of water.  The product is used to produce flexible coatings on paper, fabric, or metallic pipes.