GB479820A - Improvements in and relating to flexible-backed abradants - Google Patents

Abstract

Flexible abrasive sheets comprise a base such as paper or cloth coated with a resin made by reacting under heat a drying oil modified alkyd resin with a phenol-aldehyde resin in which abrasive particles are embedded. The abrasive may be mixed with the liquid resinous coating composition or the abrasive grains may be applied to the coated base. Examples describe (1) heating a mixture of glycerol, phthalic anhydride, linseed oil acids and linseed oil, first to 190--200 DEG C. and then to 230--240 DEG C., when a phenol-aldehyde resin is added and heating continued to the end point, after which solvents such as toluol or xylol and driers such as lead, cobalt or manganese linoleate are added; (2) linseed oil acids, paraformaldehyde and xylenol are heated first at 90--95 DEG C. and then at 120--130 DEG C.; linseed oil may replace the linseed oil acids and an oil soluble acid such as acetic acid used as catalyst; glycerol, phthalic anhydride, linseed oil acids and linseed oil are heated to 190--200 DEG C., cooled to 135 DEG C., added to the first mixture and heated to 230--240 DEG C.; (3) phenol, paraformaldehyde and a drying oil modified alkyd resin are reacted together first at 120--130 DEG C. and then at 220--230 DEG C.; (4) glycerol, phthalic anhydride, china and wood oil acids and a phenol aldehyde resin are heated at 220--230 DEG C.; (5) perilla oil, glycerol and potassium carbonate are heated to 220--230 DEG C. and a mixture of glycerol, phthalic anhydride and a phenol-aldehyde resin are added and heating continued to the end point. Paraformaldehyde may be replaced by furfurol or acetaldehyde, and phenol and xylenol may be replaced by cresol, p-phenyl-phenol, p-tertiary-butyl or amyl - phenol. In making the drying oil modified alkyl resin polyhydric alcohols such as glycerol, pentaerythritol, mannitol, ethylene or diethylene glycol or propylene glycol may be used, the polybasic carboxylic acid may be phthalic, succinic, adipic, fumaric or maleic acids or anhydrides and the drying oils may be linseed, tung or perilla oils. Rosin modified phenol-aldehyde resins may be used to replace the phenol - aldehyde resin. Specification 382,861 is referred to.