Method of continuously producing resinoid abrasive wheels for cutting hard materials

Claim 1

An improved method of continuously producing a resinoid abrasive wheel for cutting hard materials comprising the steps of preparing pore forming granules having predetermined mechanical strength and containing a substance thermally decomposable at a baking temperature for the production of the resinoid wheel, the thermally decomposable substance being selected from the group consisting of starch and funori, kneading the pore forming granules with abrasive grains and a thermosetting synthetic resin binder to prepare an abrasive composition, molding the abrasive composition into a block, heating the block by a high frequency heater, rolling the heated block containing the pore forming granules into a sheet by a multiplicity of pairs of rolls, blanking out a circular piece from the rolled sheet, and baking the circular piece to cure the binder therein and form pores in the resulting abrasive wheel by the decomposition of at least part of the thermally decomposable substance contained in the granules, wherein the improvement comprises: (a) adding a blowing agent selected from the group consisting of sodium hydrogen carbonate, amyl acetate, butyl acetate and diaminobenzene, along with the thermally decomposable substance in the step of preparing pore forming granules; and (b) forming pores by the decomposition of at least part of the thermally decomposable substance contained in the granules containing the blowing agent and by the decomposition of the blowing agent contained in the granules while curing the binder contained in the circular sheet in the baking step, the pores being larger than the pore forming granules and located where the pore forming granules were present.