GB1232808A - - Google Patents

Abstract

1,232,808. Plastic impression-taking compositions. COE LABORATORIES Inc. 19 July, 1968, No. 34574/68. Heading C3P. Plastic compositions adapted to take impressions, particularly anatomical impressions (e.g. of the mouth or ear), comprise a thermoplastic vinyl resin and a room temperature gelforming solvent system for the vinyl resin, which system comprises a benzyl radical-containing compound which is liquid at room temperature and which has a vapour pressure at room temperature not greater than 1À0 mm. mercury, and an oil extender which forms 20- 65% by volume of the solvent system, there being from 5 to 12 c.c. of solvent system per 10 grams of the vinyl resin. Preferred resins are low molecular weight methacrylate polymers or copolymers, e.g. polyethyl methacrylate, polyisobutyl methacrylate or ethyl methacrylate/butyl methacrylate copolymer, in small bead or granular form; such resins may be used in admixture with other vinyl resins, e.g. polyvinyl chloride, polyvinyl acetate or vinyl chloride-vinyl acetate copolymer. An anti-tack solid or powder, e.g. calcium carbonate, ultrafine silica or zinc stearate may suitably be included with the resin in a minor amount. Suitable as benzyl-containing liquids are benzyl alcohol and C-substituted derivatives thereof, benzyl thiol, benzyl-substituted aliphatic aldehydes, and benzyl chlorides, ketones, ethers, amines, cyanides and esters. The oil extender may be an alkyl aryl hydrocarbon oil, a naphthenic oil, a fixed oil or a vegetable oil (e.g. corn oil or cottonseed oil). To prevent "sweating out" of the aromatic hydrocarbon oils, a coupling agent may be added, e.g. certain benzyl alcohols, butyl benzoate, liquid alkyl phenols (e.g. amyl- and nonyl-phenols), hexadecyl alcohol and other alcohols having at least 10 carbon atoms, glycols and dibutyl phthalate. Other optional components include additional gel formers, e.g. relatively non-volatile etheralcohols, esters and higher molecular weight glycols; plasticizers such as dibenzyl sebacate and butyl benzyl phthalate; and odour-masking compounds, e.g. synthetic peppermint oil. For use, the composition may be stored in the form of a two-component pack, with the vinyl resin being packaged separately from the solvent system.