Abstract: A process for producing a float bath bottom refractory brick which can suppress a reaction with Na2O from glass at the surface of the refractory brick and thereby prevent flaking phenomena, which process comprises adding a potassium compound to a clayey material comprising from 30 to 45 mass % of Al2O3 and from 50 to 65 mass % of SiO2 and having a Na2O content of at most 1 mass %, so that the K2O content in the float bath bottom refractory brick to be produced would be from 2 to 4 mass %; and a refractory brick useful for a float bath bottom for production of plate glass by a float process.

Abstract: It is to provide a process for producing a float bath bottom refractory brick which can suppress a reaction with Na2O from glass at the surface of the refractory brick and thereby prevents flaking phenomena, as a refractory brick to be used for a float bath bottom for production of plate glass by float process. A process for producing a float bath bottom refractory brick using a clayey material comprising from 30 to 45 mass % of Al2O3 and from 50 to 65 mass % of SiO2 and having a Na2O content of at most 1 mass %, wherein a potassium compound is added so that the K2O content in the float bath bottom refractory brick to be produced would be from 2 to 4 mass %.

Abstract: A viscosity index improver, comprising an oil-soluble copolymer (A) having 20-70% by weight of alkyl acrylate units and 30-80% by weight of alkyl methacrylate units, and a viscosity index improver, comprising 20-80% by weight of an oil-soluble alkyl acrylate (co)polymer (A1) and 20-80% by weight of an oil-soluble methacrylate (co)polymer (A2), are capable of reducing high-temperature high-shear viscosity, particularly isoparaffin-containing high viscosity index oil, and provide luburicating oils useful as engine oil, gear lubricant and so on.

Abstract: There are disclosed a viscosity index improver comprising a polymer containing at least 70% by weight of structural units of an alkyl (meth)acryrate monomer containing not more than 10 carbon atoms in the alkyl group, and a lubrication oil, comprising said improver added to a lubrication base oll selected from the group consisting of mineral oils, MLDW oils, iso-paraffin-containing high viscosity index oils, synthetic hydrocarbon lubricating oils, synthetic ester lubricating oils, and mixture of two or more of these. The improver exhibits improved low-temperature viscosity characteristics and oxidation resistance, as compared with conventional methacrylate polymer viscosity index improvers. It gives extremely low viscosity at -40.degree. C., particularly when used in high viscosity index oils. Besides, when used in conjunction with a molybdenum-containing FM agent, it has a characteristic of providing low friction coefficient even after oxidative degradation.

Abstract: A viscosity index improver which contains a polymer dispersion comprising: a polyolefin having a weight average molecular weight of 10,000 to 500,000, a dispersant comprising a reaction product of an ethylenically unsaturated dicarboxylic acid added polyolefin with a carboxylic acid-reactive compound selected from the group consisting of an amine, a ketimine compound, an alcohol and an isocyanate compound and an organic liquid medium comprising a liquid phenolic derivative selected from the group consisiting of an alkyl phenol and an alkyl salicylate.

Abstract: Disclosed is a viscosity index improver in the form of a high-concentration non-aqueous dispersion of a low-viscosity olefinic polymer and a method of preparing the same.

Abstract: A high zirconia fused cast refractory having excellent thermal cycle resistance which comprises, as chemical components of the refractory, from 90 to 95% by weight of ZrO.sub.2, from 3.5 to 7% by weight of SiO.sub.2 and from 1 to 3% by weight of Al.sub.2 O.sub.3 and which does not substantially contain any one of P.sub.2 O.sub.5, B.sub.2 O.sub.3 and CuO.

Abstract: This invention relates to a cement-shrinkage-reducing agent and a cement composition comprising a compound of the general formula RO(AO).sub.n H (in which R represents a C.sub.1-7 alkyl or C.sub.5-6 cycloalkyl radical, A represents one or more C.sub.2-3 alkylene radicals, and n has a value of 1-10) for use in making cement mortar and concrete.