(57) This invention relates to novel coated abrasives, and, in particular, to a lapping material in sheet form.
The earliest methods of lapping employed particulate abrasive materials suspended in a liquid vehicle to form a slurry. The suspension was worked against the surface of the workpiece until the desired finish was attained.
More recently, lapping materials in pad or sheet form have been developed. U.S. Patent 4,288,233 describes lapping pads for ophthalmic lenses. While the lapping material of this invention is useful, the components thereof, i.e. diamonds, and the method of making it, i.e. metal plating, are expensive. Furthermore the lapping materials described therein are not flexible.
This invention involves a coated abrasive comprising a backing and abrasive grain adhered to said backing by means of a binder. The binder is prepared from a composition that is curable by free-radical polymerization. The composition contains abrasive grain suspended therein at the time the composition is coated onto the backing. The abrasive exhibits high endurance for extended periods of use.
The coated abrasive is prepared by a method comprising the steps of:

(a) providing a coatable composition comprising a binder curable by free-radical polymerization, said composition having lapping size abrasive grains suspended therein,

(b) coating said composition on a backing, and

(c) curing said composition by means of free-radical polymerization.