GB437604A - Manufacture of sheets from polymerisation products - Google Patents

Abstract

Sheets, films, and foils are obtained by spreading a homogeneous aqueous suspension of a synthetic polymerization product which is thermoplastic and does not harden under the influence of heat and pressure, on a support, evaporating the water and heating the layer of powdered polymerization product under a high pressure and at a temperature above the softening point of the product. The suspension may contain a dyestuff, pigment, filler, or softening agent. It may consist of an emulsion formed in the production of the polymerized product or it may be obtained from such emulsion by concentration, by evaporation or addition of powdered product, or by treatment to increase the viscosity. For the heat and pressure treatment the dried layer may be placed between polished metal plates. In an example, a polymerized mixture of vinyl chloride and methyl acrylate is dispersed with water in a colloid mill. The suspension is poured or sprayed to form a uniform layer on a metal plate and dried in stages. The dried mass is transformed into a sheet by subjection to heat and pressure. Other examples describe the production of sheets from aqueous emulsions or pastes of polyvinyl chloride and butyl phthalate, of chlorinated polyvinyl chloride, tripropyl phosphate and red iron oxide, and of a mixed polymerized product of vinyl chloride and methyl acrylate with zinc white. The sheets may be used in making laminated glass, windows for motor cars, aeroplanes, tents, and gas masks.