GB621845A - Thermoplastic composition - Google Patents

Abstract

A thermoplastic composition comprising a mixture of 50-90 per cent wax and 10-50 per cent blown vegetable oils is used for making the casting patterns which are employed in the manufacture of moulded articles such as dentures and rings and pins or other items of jewellery. The wax may be candelilla wax, carnauba wax, beeswax, palm wax, bayberry wax, ouricoury wax, ceresin wax, or the amorphous, crystalline or microcrystalline type of paraffin wax and mixtures of waxes may be employed. The blown oil may be derived from cashew shell oil, linseed oil, oiticica oil or chinawood oil and mixtures of blown oils may be employed. Fillers such as natural or synthetic resins, particularly rosin, dammar, melamine resins, phenolic resins, polystyrene or polymethyl methacrylate, may be incorporated in the composition. In the examples, compositions are described consisting of (a) blown linseed oil with candelilla wax, carnauba wax, microcrystalline wax, amorphous mineral wax, yellow beeswax or ceresin wax, (b) blown chinawood oil with candelilla wax, beeswax or ceresin wax, and (c) blown linseed oil with candelilla wax and amorphous wax, carnauba wax or rosin. The Specification as open to inspection under Sect. 91 refers to a thermoplastic composition comprising an intermixture of wax and a polymerized vegetable oil miscible therewith. This subject-matter does not appear in the Specification as accepted.ALSO:A thermoplastic composition comprising a mixture of 50 - 90 per cent wax and 10 - 50 per cent blown vegetable oil is used for making the casting patterns which are employed in the manufacture of moulded articles such as dentures and rings and pins or other items of jewellery. The wax may be candelilla wax, carnauba wax, beeswax, palm wax, bayberry wax, ouricoury wax, ceresin wax or the amorphous crystalline or microcrystalline type of paraffin wax and mixtures of waxes may be employed. The blown oil may be derived from cashew shell oil, linseed oil, oiticica oil or chinawood oil and mixtures of blown oils may be employed. Fillers such as natural or synthetic resins, particularly rosin, dammar, melamine resins, phenolic resins, polystyrene or polymethyl methacrylate, may be incorporated in the composition. In the examples, compositions are described consisting of (a) blown linseed oil with candelilla wax, carnauba wax, microcrystalline wax, amorphous mineral wax, yellow beeswax or ceresin wax, (b) blown china-wood oil with candelilla wax, beeswax or ceresin wax and (c) blown linseed oil with candelilla wax and omorphous wax, carnauba wax or rosin. The Specification as open to inspection under Sect. 91 refers to a thermoplastic composition comprising an intermixture of wax and a polymerized vegetable oil miscible therewith. This subject-matter does not appear in the Specification as accepted.