Abstract: The film-forming agent of the invention is a blend of a silica organosol, of which the silica particles have a specified specific surface area and specified densities of surface groups including silanol groups, alkoxy groups and trimethyl silyl groups, and a diorganopolysiloxane of a specified viscosity terminated at each molecular chain end with a silanolic hydroxy group. The film-forming agent is useful as a skin-care preparation for preventing chapping of hands of people having frequent occasions of contacting with water to exhibit durable water repellency.

Abstract: A method for manufacturing synthetic silica glass by reacting methyl silicate and aqueous ammonia, dispersing the silica particles produced in water, solidifying the silica by the addition of methyl silicate and heating, dehydrating, de-solventing, decarburizing and sintering the solid silica to produce a glass product. The sintered glass may be pulverized to produce a powder. The inventive method is easily carried out and avoids the high energy costs of the prior art. The glass product obtained exhibits excellent high temperature viscosity.

Abstract: A method for the preparation of a stable silica organosol in a hydrophobic organic solvent is proposed. The method comprises (a) hydrolyzing a tetraalkoxy silane, e.g. tetraethoxy silane, in an alcoholic medium in the presence of a limited amount of water and ammonia as a catalyst under controlled conditions so as to produce a silica alcosol in which the silica particles satisfy the requirements that the alkoxy groups and silanolic hydroxy groups are bonded to the silicon atoms on the surface in densities of at least 3.5 .mu. moles/m.sup.2 and not exceeding 2 .mu. mmoles/m.sup.2, respectively, and the specific surface area S given in m.sup.2 /g and the average particle diameter D given in nm of the silica particles satisfy the relationship of S.times.D.gtoreq.5000, D being 1 nm or larger, and (b) admixing the alcosol of silica particles with an organosilicon compound selected from the group consisting of the compounds represented by the general formula R.sub.4-n SiX.sub.n, (R.sub.3 Si).sub.

Abstract: A process for preparing a silicone composition is provided, which comprises a step of distilling away an organic solvent from a mixture of (1) a low viscosity silicone oil represented by the general formula, R.sub.a SiO.sub.(4-a)/2 (wherein R's may be the same or different, each being an unsubstituted or substituted, monovalent hydrocarbon residue containing 1 to 6 carbon atoms; and "a" ranges from 1.8 to 2.3), and having a viscosity of 100 centistokes or less at 25.degree. C., with (2) an organosilica sol containing, as a dispersoid, spherical porous trimethylsilylated silica particles having an average particle size of 10 to 100 millimicrons, a specific surface area of 300 m.sup.2 /g or above, a trimethylsilyl group density of 0.5 to 10 micromol/m.sup.2, an alkoxy group density of 0.5 to 10 micromole/m.sup.2, and a silanol group density of 0.5 to 5 micromol/m.sup.2, and a step of homogeneously kneading the resulting mixture under shearing stress.

Abstract: The invention provides a method for the preparation of synthetic fused silica glass containing a very small amount of hydroxyl groups and has a high viscosity at high temperatures suitable for use as a material of articles for semiconductor processing at high temperatures, such as a crucible for Czochralski single crystal growing of semiconductor silicon. The method comprises hydrolyzing methyl silicate in a medium containing a specified amount of ammonia as a hydrolysis catalyst to form silica particles which are heat-treated in several successive steps.

Abstract: An improved sol-gel method is proposed for the preparation of a transparent silica gel block, in which a deposit of fine silica particles having a controlled particle diameter as prepared by hydrolyzing an alkoxy silane in the presence of ammonia is dispersed in a silica sol solution prepared in an acidic condition and settled therein to form a structure of closest-packing prior to gelation, drying, sintering and vitrification so that silica glass blocks can be obtained with low volume shrinkage from the wet gel in an improved yield without cracks, bubbles and haziness. The improvement can be further enhanced when two separately prepared deposits of silica particles having larger and smaller particle diameters are dispersed as combined in the silica sol solution, especially, when the particle diameter in one deposit is not exceeding 22.5% of that in the other deposit.

Abstract: A process for producing fine spherical silica, comprising a step of hydrolyzing an alkoxysilane in a mixed solution comprising water and alcohol and containing an alkaline catalyst, wherein the amount of said alkaline catalyst is 0.5 to 10 in molar ratio to the alkoxysilane used, the concentration of water in said mixed solution of water and alcohol in 5 to 20 mol/lit., and the reaction temperature for said hydrolysis is 30.degree. C. or more.According to this process, there can be obtained highly monodisperse spherical silica containing only a very small amount of impurities and having a particle size of 100 nm or less.

Abstract: This invention is a method for preventing sticking of a resin plate surface by coating the solution of binder and photopolymerizable monomer on the surface of a photosensitive resin composed of binder, photopolymerizable monomer, and photopolymerization initiator, developing relief images by a photomechanical process, and then by drying the coating solution.