GB520262A - Improvements relating to abrasive or polishing compositions, or articles - Google Patents

Abstract

520,262. Abrasive compositions etc; polyamide compositions. TRIGGS, W. W. (Du Pont de Nemours & Co., E. I.). Oct. 28, 1938, No. 31199. [Class 2 (iii)] An abrasive or polishing composition or article includes, as binder, one or more superpolyamides such as are described in Specifications 461,236, 461,237 and 474,999, and having intrinsic viscosities above 0.4, e.g., between 0.6 and 2.0. The abrasive made is admixed with the polyamide in powdered or molten condition, or may be added to a solution thereof the mixture of abrasive and polyamide being isolated by precipitation or by evaporation' of the solvent; the abrasive may be added to the starting materials for or during the preparation of the polyamide. Moulding of the mixture is effected under pressure and at a temperature sufficient to soften the polyamide. Softeners and plasticizers, e.g., orthohydroxy diphenyl and diphenylol propane, pigments, fillers, cellulose derivatives and other types of polymers may be added. Abrasives &c. include diamond, quartz, sand, garnet, steel, feldspar, glass, pumice and chalk. Specified articles are grinding and polishing wheels, millstones, scythe stones, whetstones, pulp stones, hones, cutting instruments, drilling tools, sandpaper and polishing cloths. In examples, (1) a grinding wheel is moulded from a mixture of aluminium oxide and a formic acid solution of a polyamide interpolymer derived from hexamethylene diammonium adipate and decamethylene diammonium sebacate the formic acid being removed by heating, (2) emery is added to a phenol solution of polyhexamethylane adipamide, and precipitation effected with ethyl acetate, (3) carborundum is mixed with finely-divided polyhexamethylene adipamide, (4) diatomaceous earth is added to a phenol solution of polyhexamethylene adipamide and precipitation effected with an alcohol-ethyl acetate mixture.