Use of fine-grained pentaerythritol, dipentaerythritol or a mixture of these compounds as a pore forming additive in porous ceramic products such as ceramic abrasive wheels and ceramic filters.

The instant invention relates generally to abrasive stones for use in processing workpiece surfaces. The abrasive stones generally are produced by combining an epoxy novalac resin mixture with microballoons and a catalyst. The mixture is put into a mold, cold pressed, and then cured, creating abrasive stones having a uniform surface and bulk structure with a uniform hardness, suitable for workpiece processing.

An abrasive article having certain minimum levels of permeability to fluids comprises about 40 to 80%, by volume interconnected porosity and effective amounts of abrasive grain and bond to carry out soft grinding and deep cut grinding operations. The high permeability to the passage of fluids and interconnected porosity provides an open structure of channels to permit the passage of fluid through the abrasive article and the removal of swarf from the workpiece during grinding operations.

A press felt base (single or multiple layer) having a plastic, fiber reinforced resinous matrix surface, wherein the surface is composed of a resin. The press felt base also having textile fibers distributed throughout the resin and having open air channels and voids throughout the resin once it is hardened.

Disclosed is a method of producing porous vitrified grinder, where melamine cyanurate is used as a pore-imparting agent. The grinder has a long life and has an improved grinding capacity.

The grinding media is formed of a concentration of agglomerate free hard particles exceeding 50 percent by weight of the media, wherein the particles are chelated by a dispersing agent, surface treated with a surfactant, mixed with polyether polyol and polyisocyanate plus a catalyst and water and thereafter rapidly cured in a closed mold which has been preheated to a temperature exceeding 50.degree. C. and a pressure of 60 to 120 PSIG. The water reacts during curing to create a polyurea linkage ...

Organic bonded abrasive bodies such as snagging wheels and wheel segments for conditioning billets, slabs, and castings have abrading portions with 0 to 8% pores by volume, a low abrasive content of from 24 to 45% by volume of 4 to 36 grit size abrasive, substantially constant volume of a thermosetting resin of from 18 to 24% by volume and a high content of filler material constituting from 29% to 56% by volume of the body and wherein at least 80% by volume of the filler material is inorganic ma...

A resinoid-bonded grinding wheel employing the ultra-hard abrasives such as cubic boron nitride or diamond are formed with a support member which is made of a heat insulating material such as ceramics for preventing a thermal expansion of the grinding wheel and maintaining a precision grinding operation.

A porous, cured unsaturated polyester resin bonded grinding tool having very fine pores uniformly dispersed therein is produced by molding a homogeneous mixture comprising abrasive grains, a water-in-oil emulsion of an uncured unsaturated polyester resin and a curing catalyst to form a mold of the intended grinding stone shape, curing the unsaturated polyester resin contained in the mold, and drying the mold to remove the water therefrom.

An improved process is disclosed for making grinding wheels wherein a vinyl resin, such as polystyrene, or other suitable thermoplastic material is incorporated in the refractory composition with an epoxy binder or other binder which cures in the proper temperature range. The flat surface grinding wheels made in accordance with the invention and used on double-disc grinders function more effectively and facilitate rapid grinding and their useful life can be increased at least 3 or 4 times.