GB1125137A - Improved abrasive compositions and structures - Google Patents

Abstract

1,125,137. Abrasive composition. UNION CARBIDE CORP. 3 Sept., 1965 [4 Sept., 1964], No. 37796/65. Headings C3B and C3R. An abrasive composition comprises a major amount of abrasive grains, a binding amount of a heat hardenable resin binder, and a thermoplastic polyhydroxy ether of formula wherein D is the radical residium of a dihydric phenol, E is a hydroxyl-containing radical residium of an epoxide, and n represents the degree of polymerization and has a value of at least 30, said polyhydroxy ether being present in an amount of up to 60 parts by weight to a 100 parts by weight of the heat hardenable binder. Mixtures of such thermoplastic polyhydroxy ethers may be used. The phenol may be a dihydric mononuclear phenol, such as hydroquinone or resorcinol or a dihydric polynuclear phenol such as those having general formula wherein Ar is an aromatic divalent hydrocarbon such as naphthylene and phenylene, Y and Y 1 are alkyl radicals, preferably having from one to 4 carbon atoms, halogen atoms or alkoxy radicals, R and Z are integers having a value from 0 to a maximum corresponding to the number of hydrogen atoms in the aromatic radical which can be replaced by substituents and R 1 is a bond between two carbon atoms as in dihydroxy diphenyl, or is a divalent radical including and divalent hydrocarbon radicals such as alkylene, alkylidene, divalent cycloaliphatic radicals, e.g. cycloalkylene and cycloalkylidene, halogenated, alkoxy or aryloxy substituted alkylene, alkylidene radicals and divalent cycloaliphatic radicals, as well as alkarylene and aromatic radicals including halogenated, alkyl, alkoxy or aryloxy substituted aromatic radicals, and radicals containing a ring fused to the Ar group. R 1 may also be a divalent polyalkoxy or polysiloxy radical, or two or more alkylidene radicals separated by an aromatic ring, a tertiary amino group, an ether linkage, a carbonyl group or a sulphur-containing group such as sulphoxide. Numerous suitable polynuclear phenols are specified. The epoxide contributing the hydroxyl containing radical residium, E, can be a monoepoxide or a diepoxide. Numerous suitable compounds are specified. Heat-hardenable resins may be phenol-aldehyde, amine-aldehyde resins, novolaks and resoles, a hardening amount of a methylene engendering hardening agent may be present. The abrasive grains may be metal oxides, e.g. aluminium oxide, natural corundum, diamond and silicon carbide. A wetting agent such as a liquid heat-hardenable resin or solvent such as furfural or furfural/cresol mixture may be used. Fillers, such as cryolite, fluospar, magnesium oxide or silica may be used. The mixture may be moulded and heated at e.g. 365‹ C., to form grinding wheels.