Chemical compositions

Rigid thermoplastic compositions comprise crystalline polypropylene and 5 to 15 weight per cent based on the polymer of one or more plasticizers of solubility parameter 9.6 to 10.7 and selected from esters, dibenzyl ether, dicresyl glyceryl ether and benzophenone. Specified plasticizers are dibenzyl phthalate, butylbenzyl phthalate, butyl phthalyl butyl glycolate, diethylene glycol dibenzoate, di-methoxyethyl phthalate, 1-phenylethyl benzoate, triethylene glycol dibenzoate, benzyl benzoate, ethylphthalyl ethyl glycolate, phenyl diglycol carbonate, di-phenoxyethyl diglycolate, bis(dimethylphenyl) carbonate, methyl phthalyl ethyl glycolate, glyceryl tribenzoate, triphenyl phosphate, tritolyl phosphate, dibenzyl ether, dicresyl glyceryl ether, and benzophenone. The compositions may also contain stabilizers, e.g. alkyl dithio propionates and hindered phenols; fillers and pigments, e.g. calcium carbonate, china clay, mica and silica; and may be made into films and fibres, and moulded to form other shaped articles.