GB479767A - Improvements in or relating to abrasive articles and methods and apparatus for manufacturing the same - Google Patents

Abstract

479,767. Flexible abrasive sheets. CARBORUNDUM CO. Aug. 10, 1936, No. 22022. Convention date, Sept. 5, 1935. [Class 60] A flexible abrasive article comprises a single layer of abrasive grains partially embedded in a surface of a self-supporting flexible sheet of a bonding material which is thinner than the major dimension of the abrasive grains. A flexible reinforcement such as wire gauze or mosquito netting may be embedded in the sheet. The bonding material may be a heat hardenable, permanently thermoplastic, or air drying adhesive, initially solid, in solution or dispersion or liquid, e.g. phenol-aldehyde condensation products which may be oilmodified, vinyl resins such as polyvinyl chloride or acetate or a vinyl ester modified by an aldehyde such as formaldehyde or acetaldehyde, alkyd resin, cellulose esters or ethers, varnishes or lacquers. A mixture of abrasive grains and powdered bonding material is fed on to an endless belt 3 from a hopper 6. The mixture is carried over an electrical heating element 9 where the bonding material is softened to bind the abrasive grains and flows to leave the upper parts of the abrasive grains projecting. Cooling air from a blower 12 solidifies the adhesive and the sheet thus formed is removed from the belt 3 by a scraper 13 and rolled up on a roller 14. In an alternative form of apparatus, liquid bonding material is first applied, followed by abrasive grains. Additional adhesive may be sprayed on to form a sizing coating. The belt may have a surface of amalgamated, highly polished, or chromiumplated metal and adhesion of the bonding material may be reduced by applying a solvent or by coating with talc, mica or soap. The formed sheet may be further heat treated before or after rolling up, for example, by passage through hot mercury or by the method described in Specification 467,111.