GB470014A - Improvements in compounded plastics - Google Patents

Abstract

A composite material comprises a heat treated mixture of graphite and an olefine polysulphide plastic, with or without amorphous carbon and/or other fillers. In preparing the material, the plastic is masticated with softening and activating agents such as dibenzothiazyl disulphide, tetramethylthiuram disulphide, diphenylguanidine and zinc oxide, and with fillers such as carbon black, kaolin, blanc fixe, and fibrous material, e.g. leather scrap and asbestos powder, graphite is incorporated, and the product is heated under pressure in one or more stages to polymerize the plastic. Partial polymerization may be effected by rolling or pressing the material into sheets or by extruding with heat, and the final polymerization by dry heat or steam heat or by the "wrapped cure" as in the vulcanization and curing of rubber. In the production of thin articles such as washers, the compounded material may be rolled into sheets, polymerized between heated platens, and the articles then punched from the sheet. In the manufacture of more massive articles, e.g. bearings, the compounded material, in the form of a pile of sheets or in blocks, may be partly polymerized, the agglomerated mass coarsely ground, and the powder then moulded under heat and pressure. In examples, the material is prepared from mixes containing an olefine polysulphide plastic, graphite, carbon black, zinc oxide, diphenyl guanidine, dibenzothiazyl disulphide, and stearic acid with or without blanc fixe. Specifications 302,270, [Class 2 (iii)], 354,310, 354,394, and 360,890 are referred to.