Abstract: A colour developing composition for use in pressure-sensitive (carbonless) copying paper sets comprises an inorganic pigment extender (e.g. kaolin, talc or calcined kaolin) and a hydrated silica/hydrated alumina composite. The composition is produced by precipitating the hydrated silica/hydrated alumina composite in the presence of the extender by the following steps:a) gradually adding a metal silicate solution to a solution of an aluminium salt which is initially at a pH below 4 until the pH of the resulting mixture is approximately 4, thereby to induce some precipitation and to form a sol;b) gradually adding alkali to said sol to raise the pH to approximately 7, thereby to induce further precipitation and gel the sol or further gel the sol, said gelled sol being a hydrated silica/hydrated alumina composite;c) separating the resulting product from the aqueous medium and washing to remove dissolved salts; andd) drying the washed product and reducing it in particle size.

Abstract: A composite yet monolithic free abrasive grinding lap includes a sintered porous matrix of ceramic or metal material and a quantity of silicon filler material, substantially completely filling the pores of the sintered porous matrix preform at least throughout an effective region of the lap that is to come in contact with a workpiece to be acted upon by the lap. The lap may further have a multitude of abrasive particles embedded in the filler material at the effective region. The lap is made by first slip-casting a preform, then freezing and freeze-drying the same, followed by lightly sintering the dry preform into a porous matrix preform, bringing the temperature of the preform to above the melting point of the silicon filling material, and filling the pores with the filling material in its molten state.

Abstract: An abrasive compact with a substantially solid body is provided from a mass of abrasive particles which are bonded together on a particle-to-particle basis. A network of interstices is formed within the body by removing the metallic second phase by-product of a solvent catalyst sintering aid. The network of interstices is filled with the carbide by product of a non-catalyst sintering aid forking a solid body. A substrate is bonded to some of the particles and to some of the carbide filling the network of interstices.

Abstract: Abrasive article using sintered sol-gel abrasive particles mixed with other particles having greater friability, and carried in a bond.

Abstract: A process for preparing an abrasive sheet having abrasive particles adhered on a base sheet in monolayer is disclosed, wherein mixed slurry of abrasive particles and binder adhesive is foamed, the foamed slurry is uniformaly painted on the base sheet, and foams formed in the slurry is broken by heating thereby to form the abrasive sheet having good flatness.

Abstract: A cutter comprises a base plate formed by joining two thin annular members with each other; a groove formed in the outer periphery of the base plate; an annular metal supporting plate, to be positioned in the groove of the base plate, having a plurality of openings formed therethrough; and a cutting member formed around the outer periphery of the base plate with the supporting plate thereby. In the above construction, the cutting member is formed by sintering a mixture of abrasive grains and powders formed by alloying copper, cobalt and tin with each other.Since the base plate is formed by adhereing the two annular members to each other, the strength of the base plate is higher than those of conventional cutters. Therefore, there is little possibility that the base is damaged while the cutter is being used.In addition, since the supporting plate is sandwiched between the two annular members, and the cutting member is bonded, in a high strength, with the supporting plate having openings formed therethrough.

Abstract: A heat-stable iron oxide black pigment resistant to hydrothermal treatment in air at temperatures above 180.degree. C. and which has a specific BET surface of 0.5 to 5 m.sup.2 /g is useful as a coloring agent for building materials, paints, cements, bricks and so forth and is prepared by reacting an aqueous solution of FeOOH, iron (II) salts and alkalis at elevated temperature and precipitating iron oxide from the solution with Na.sub.2 CO.sub.3 at temperatures in the range from 80.degree. C. to the boiling point of the solution.

Abstract: An abrasive product comprising abrasive grains bonded together or bonded to at least one major surface of a backing sheet, by a binder formed from a precursor comprising an aminoplast resin having on average at least 1.1 pendant .alpha.,.beta.-unsaturated carbonyl groups per molecule. The binder is formed by curing the precursor at the .alpha.,.beta.-unsaturated site of the carbonyl group, by radiation energy or by heat, in the presence of an appropriate initiator system. The aminoplast resin can also contain pendant amino or hydroxy functional groups, which allow polymerization with condensation curable resins, such as phenolic, melamine, urea, urethane, and furfural resins. Polymerization at the unsaturated site of .alpha.,.beta.-unsaturated carbonyl group can be effected either by radiation energy or by heat, and curing at the sites of the amino or hydroxy functional group can be subsequently effected by heat.

Abstract: A powdery or granular fat or oil composition in the form of a powder or granules having a water content of 15% by weight or less, a maximum particle diameter of not greater than 10 mm, an average particle diameter of not greater than 5 mm and an angle of repose of not greater than 70%. The composition is produced simply by mixing only a fat or oil, a base material capable of occlusion or absorption of the fat or oil and a liquid polyol at a temperature at which the fat or oil is molten.

Abstract: Abrasive article using sintered sol-gel abrasive particles mixed with other particles having greater friability, and carried in a bond.

Abstract: Pearl luster pigments based on mica flakes coated with metal oxides are provided with a top coating of tin dioxide and/or cerium dioxide to improve their stability in glazes and enamels.

Abstract: An abrasive sheet is formed by uniformly painting slurry made of mixture of abrasive particles and adhesives on a surface of a base sheet with a pattern of irregularities by embossing. The slurry layer formed on the sheet hardens by drying at adequate temperature to form an abrasive layer. The abrasive layer has high and low abrasive parts formed by the surface tension of slurry, corresponding to the irregularities of the base sheet. The abrasive sheet is characterized by good planar precision of the abrasive layer, hardness to be peeled off the base sheet, and relatively easy producing method in which grooves are formed by the surface tension.

Abstract: Abrasive particles and articles made from cubic boron nitride derived from coated hexagonal boron nitride which is substantially free of oxides and volatile contaminants. Polycrystalline CBN is prepared from HBN by removing oxide from the surface of HBN particles to form HBN particles having a substantially oxide-free surface. The HBN particles having a substantially oxide-free surface are coated with an agent which is capable of preventing re-oxidation of the surface of the HBN particles to form coated HBN particles in a substantially oxide-free state. The coated HBN particles in a substantially oxide-free state are then converted to a polycrystalline CBN by direct conversion of HBN to CBN. Coating agents include metals, metal carbides, metal nitrides and metal borides. A preferred coating agent is titanium carbide.

Abstract: An abrasive grain with an aluminum oxide base which is distinguished by good throwing power and by a good capability of being integrated in flexible abrasives or in grinding wheels with artificial resin bonding.

Abstract: An abrasive grain on the basis of silicon carbide with a binder-free coating of highly dispersed silicon, aluminum or titanium oxide for preferred use in resin-bonded or ceramic-bonded abrasive wheels.

Abstract: Coated abrasive material having blends of abrasive grains of sol gel process alumina and alumina-zirconia in a volume ratio of at least 15% sol gel abrasive grain provide improved performance in certain grinding applications and a more universal coated abrasive product for a wider range of grinding applications than such products of either abrasive grain alone.

Abstract: A coated abrasive is disclosed that has been oversized with an anti-loading amount of a quaternary ammonium anti-static compound, comprising from about 15 to about 35 carbon atoms and a molecular weight not less than about 300, have been found to have a combination of anti-static, lubricity and anti-loading characteristics which provide improved abrading efficiency and longer abrading life.

Abstract: Aggregation of kaolin particles by wet processing using a hydrothermal technique is described. Calcined clay is first digested in a solution containing NaOH and the obtained sodium silicate solution is separated. Aggregation of uncalcined clay particles by hydrothermal treatment is then carried out using the obtained solution. The method enables aggregation of low grade clays unsuitable for calcination. A two-stage hydrothermal process is also described. Bleaching with oxygen or bleaching compounds may be effected during hydrothermal treatment.

Abstract: A method for form grinding gears is disclosed using diamond or cubic boron nitride as the abrasive including form grinding a female wheel with a master gear form grinding wheel to produce a desired gear tooth profile on the circumference of the female wheel. The female wheel is then made oversize by bonding diamond or cubic boron nitride abrasive to its grinding surface. A male wheel is then form ground with the female wheel to produce a undersized tooth profile on the male wheel. After the male wheel is plated with diamond or cubic boron nitride abrasive it is at the desired tooth profile and can then be used to form grind gears having the desired tooth profile.

Abstract: A pigment paste comprising a pigment and as a pigment dispersing agent, a compound having a basic structure represented by the following formula ##STR1## wherein R.sub.1 represents a hydrogen atom or a C.sub.1 -C.sub.4 alkyl group, and R.sub.2 represents a residue of a diol or polyol, or a mixture of said pigment dispersing agent and an organic solvent, said pigment being dispersed in said pigment dispersing agent or in said mixture.