Flexible polishing wheel and method for producing same

Claim 1

An abrasive polishing wheel having a "Shore A" hardness of less than 96 and comprising, (a) an abrasive grain in an amount of from about 55 to about 90% of the theoretical weight of grain required to fill the volume occupied by the wheel, (b) from about 40% to about 55% by volume of an elastomer bond, said elastomer having an unfilled cured "Shore A" hardness of from about 50 to about 60 and a density of greater than 1 gram/cm 3 , (c) from zero up to about less than 15% by volume of an inert filler having an average particle diameter of less than 10 microns, and (d) less than 10% by volume of voids.

Claim 7

A method for cavity molding a polishing wheel characterized by its freedom from loading, chattering and smearing which comprises: (1) determining the apparent volume of dry particulate abrasive grains essential to fill the wheel mold cavity under densest packing arrangement, (2) reducing the apparent volume of said abrasive grains by a factor of at least 0.1 but not more than 0.45, (3) mixing the reduced volume of abrasive grains with (4a) a mixture of organic liquids which react to form an essentially foam-free solid polymer, said solid polymer characterized by a (Shore A) hardness of more than 50 but not more than about 60 in a volume not more than about 55% and not less than 40% of said wheel mold cavity volume and (4b) a volume of particulate filler, said volume being less than the difference between said mold volume and the sum of the true volume of the adjusted abrasive plus the volume of the solid convertible liquids, but sufficient to reduce the total voids volume in the cured wheel to less than 15% of the mold volume, (5) filling the molds with the plastic mixture and (6) allowing the plastic mixture to convert to a solid polymeric form in the mold before removal.

Claim 8

A method for cavity molding a polishing wheel characterized by its freedom from loading, chattering and smearing which comprises: (1) determining the apparent volume of dry particulate abrasive grains essential to fill the wheel mold cavity under densest packing arrangement, (2) reducing the apparent volume of said abrasive grains by a factor of at least 0.1 but not more than 0.45, (3) mixing the reduced volume of abrasive grains with (4a) a mixture of organic liquids which react to form an essentially foam-free solid polymer, said solid polymer characterized by a (Shore A) hardness of more than 50 but not more than about 60 in a volume not more than about 55% and not less than 40% of said wheel mold cavity volume and (4b) a volume of particulate filler, said volume being less than the difference between said mold volume and the sum of the true volume of the adjusted abrasive plus the volume of the solid convertible liquids, but sufficient to reduce the total voids volume in the cured wheel to less than 15% of the mold volume, (5) filling the molds with the plastic mixture and (6) allowing the plastic mixture to convert to a solid polymeric form in the mold before removal.