Abrasive grains rigidly bonded to each other form aggregates which are dispersed in a resilient matrix of an abrasive wheel so that the aggregates do not significantly interfere with each other's individual movement under grinding stresses against the resilient restraint of the matrix. The wheels remove metal from a workpiece much faster and lose less abrasive material than corresponding wheels in which the same abrasive particles are individually embedded in the same matrix.
This application is a continuation-in-part of application Ser. No. 416,830, filed Nov. 19, 1973, and now abandoned, which is a continution of abandoned application Ser. No. 88,981, filed Nov. 12, 1970, the last-mentioned application being a continuation-in-part of the abandoned application Ser. No. 834,885, filed June 19, 1969.
A hybrid type resinoid grindstone including abrasive agglomerates which are held together by a thermosetting synthetic resin used as a bonding agent, wherein each of the abrasive agglomerates includes sol-gel abrasive grains which are held together by a vitrified bonding agent. In the present hybrid type resinoid grindstone of the present invention, each of the sol-gel abrasive grains, which are held together by the vitrified bonding agent, restores its sharpness as a result of each of the successive removals of fine crystals with application of an impact or shock to the sol-gel abrasive grain, as in a vitrified grindstone, during a grinding operation.
The present invention provides phenolic resin-based adhesives which do not produce waste water and industrial wastes and which have good adhesive force, especially after being exposed to thermal history. That is, the present invention provides a phenolic resin-based adhesive composition which contains a polyvinyl butyral, a novolak type phenolic resin or a novolak type phenolic resin and a resol type phenolic resin, and hexamethylenetetramine and which is obtained by uniformly melt-mixing these components, or a phenolic resin-based adhesive composition which contains a polyvinyl butyral, an epoxy resin, a novolak type phenolic resin or a novolak type phenolic resin and a resol type phenolic resin, and hexamethylenetetramine and which is obtained by uniformly melt-mixing these components.
A sound- and/or vibration-damping coating, which comprises a layer of a relatively hard substance (2) having pores, interstices, cavities (3) and/or hollows (12) containing a material (4) which has a higher plasticity or elasticity than said substance (2), and an element provided with said coating. This coating may be applied on said element by applying to the surface of the latter a surface treatment ensuring the adhesion of the layer of relatively hard substance (2), by applying this layer to the so treated surface by projection of said substance in the at least molten state and as droplets, by using known per se techniques, and by entering said material (4) into cavities (3) formed between coagulated droplets of said substance (2).
An abrasive article comprising a plurality of separated abrasive agglomerates distributed within a matrix of undulated filaments is provided. The invention also provides a method of making an abrasive article comprising forming, within a lofty open web comprising undulated filaments bonded at points of mutual contact, a plurality of separated abrasive agglomerates to provide an abrasive agglomerate-impregnated web. Articles may be prepared of the agglomerate-impregnated web per se or by laminating layers of the web together preferably under pressure. Exemplary articles include abrasive wheels, discs, belts, sheets, blocks and the like.
A polishing tool for polishing optical and technical glass, semiconductors, ceramics and other materials has a high concentration of cerium dioxide or aluminum oxide particles in the quantity of 85-96% by weight, and a high molecular binder based on synthetic rubber and including a combination of high-molecular components and other components for vulcanization, plasticization and stabilization.
