Abstract: A curable silicone composition based on an organopolysiloxane having a cyclotrisiloxane structure quickly cures by brief heating or ultraviolet exposure. It further contains an acid, acid generator, base or base generator or an oniom salt photo-initiator as a curing agent. The cured product has release property from adhesive substance which remains unchanged with the lapse of time and good mold release properties, and thus provides a lightly releasable cured film. The composition is widely used as adhesive tape backing agents, mold release agents, protective coating agents, water and oil repellent agents, and paint base.

Abstract: Proposed is a radiation-curable organopolysiloxane composition which is useful as a coating agent for the formation of a releasable coating film on a substrate to serve as a releasable sheet without the problem due to generation of peeling noises. The composition essentially comprises, as a blend, (a) a first organopolysiloxane having a specified viscosity and containing (meth)acryloxyalkyl groups bonded to the silicon atoms in a specified content and (b) a second organopolysiloxane having a specified viscosity and containing (meth)acrylaminoalkyl groups bonded to the silicon atoms in a specified content, the weight proportion of the second organopolysiloxane to the first organopolysiloxane being in a specified range.

Abstract: A novel method is disclosed for the preparation of a (meth)acryloxyalkyl group-containing organopolysiloxane having a linear structure by the ring-opening siloxane rearrangement polymerization reaction of a (meth)acryloxyalkyl group-containing cyclic organopolysiloxane oligomer either alone or in combination with a cyclic organopolysiloxane oligomer having no (meth)acryloxyalkyl groups. Different from conventional acidic catalyst, the reaction can be promoted by the use of a cation-exchange resin in the H.sup.+ form which can be readily removed from the polymerization mixture after completion of the polymerization reaction leaving no acidic matter which influences on the stability of the product. The catalytic efficiency of the cation-exchange resin can be further enhanced when the resin is, prior to contacting with the cyclic organopolysiloxane oligomer(s), impregnated or swollen with a polar organic solvent such as tetrahydrofuran.

Abstract: Proposed is an improved aqueous silicone emulsion composition for surface-release treatment comprising a vinyl-containing organopolysiloxane and an organohydrogenpolysiloxane emulsified is an aqueous medium with addition of a platinum compound as a catalyst for the hydrosilation reaction between the silicon-bonded vinyl groups and silicon-bonded hydrogen atoms. Different from conventional silicone emulsion compositions of this type having a pH value of around neutrality, the inventive silicone emulsion composition has a pH value not higher than 5 so that a quite unexpected advantage can be obtained that the stability of the emulsion composition in the curability and other properties after a long period of storage and against mechanical working can be greatly improved.

Abstract: Proposed is an improved radiation-curable organopolysiloxane composition capable of giving a cured surface film on a substrate surface which exhibits excellent releasability against sticky substances. The composition is obtained by combining two kinds of (meth)acryloxyalkyl-containing organopolysiloxanes in a specified weight proportion, of which one has a relatively large degree of polymerization but contains only a relatively small amount of the silicon-bonded (meth)acryloxyalkyl groups while the other has a relatively small degree of polymerization but contains a relatively large amount of the silicon-bonded (meth)acryloxyalkyl groups.

Abstract: Disclosed is a method for imparting anti-sticking surface-releasability to the surface of a substrate which comprises: coating the surface with a novel radiation-curable (meth)acryloxy-containing organopolysiloxane; and curing the coating layer by the irradiation with radiation such as electron beams and ultraviolet light. Different from conventional radiation-curable (meth)acryloxy-containing organopolysiloxanes, the novel organopolysiloxane here used is characteristic in comprising at least one trifunctional organosiloxane unit in a molecule, by virtue of which the (meth)acryloxy-containing organopolysiloxane has good curability by the irradiation to exhibit excellent surface-releasability with high durability against aging.

Abstract: A dry PS plate having a substrate provided thereon with a photopolymerizable light-sensitive layer and a silicone rubber layer in that order. The silicone rubber layer comprises a product obtained by crosslinking through addition reaction the following components:(a) an alkenylpolysiloxane having at least two alkenyl groups directly bonded to the silicon atoms in each molecule thereof; and(b) a hydrogen polysiloxane of the following general formula I: ##STR1## wherein R.sup.1 and R.sup.2 independently represent a hydrogen atom or methyl group, R.sup.3 and R.sup.4 independently represent a methyl, vinyl or phenyl group, m+n is 5 to 30 and m:n is 3:1 to 1:3. The dry PS plate provides a lithographic printing plate exhibiting excellent tone reproducibility and printing durability as well as not being subject to background contamination.

Abstract: An acrylic rubbery polymer having remarkably improved cold resistance can be prepared by modification with an organopolysiloxane by the emulsion copolymerization of a monomeric mixture of two acrylic monomers, of which one is, for example, an alkyl acrylate and the other is an acrylic compound having, in a molecule, at least one ethylenically unsaturated group other than acrylic group in an aqueous emulsion of an organopolysiloxane having a substantial amount of mercapto-substituted monovalent hydrocarbon groups bonded to the silicon atoms.

Abstract: The invention provides a high-sensitivity ultraviolet-curable organopolysiloxane composition suitable for use as a surface-release treatment of various substrate such as release-paper sheets and the like. The composition comprises, as the essential ingredients, (a) an organopolysiloxane having a viscosity in the range from 50 to 3000 centipoise at 25.degree. C. and containing, in a molecule, at least one (meth)acryloxy-substituted monovalent hydrocarbon group or at least one epoxy- or glycidyloxy-substituted monovalent hydrocarbon group, and (b) a sulfonate compound such as 2-hydroxy-3-oxy-2,3-diphenylpropyl methanesulfonate as the photopolymerization initiator. The sensitivity of the composition to photopolymerization can be further increased by the addition of a specific salt such as sodium hexafluoroantimonate and sodium hexafluorophosphate.

Abstract: A process of correcting a dry lithographic printing plate which comprises applying to an unwanted area of an ink-accepting area in the dry lithographic printing plate consisting of ink-repellent areas comprising a silicone rubber layer and ink-accepting area, a correcting solution comprising the following components:______________________________________ amount (parts by weight) ______________________________________ (a) Linear organopolysiloxane having three 100 alkoxy groups at both terminal ends (b) Titanium based condensation catalyst 0.1 to 5 (c) Organic solvent. 100 to 5,000 ______________________________________The plate surface retouching solution provides a coating which has a good adhesion to a light-sensitive layer and a good resistance to printing.

Abstract: The surface-modified polymethylsilsesquioxane spherical fine particles of this invention comprise polymethylsilsesquioxane spherical fine particles serving as nuclei, and at least one member of an alkyl group having two or more carbon atoms, an alkenyl group, a phenyl group, an epoxy group, an acryloxy group and an amino group is bonded to the surface of a particle. They are prepared by a process comprising the step of carrying out reaction in an aqueous suspension of polymethylsilsesquioxane fine particles in the presence of an alkali catalyst. The surface-modified spherical fine particles can have various organic groups on their surfaces, and are used in various fields such as rubbers, plastics, coating materials, inks, and cosmetics, depending on the types of the organic groups.

Abstract: A radiation curable organopolysiloxane-containing composition is disclosed which is curable by the irradiation with actinic rays in a relatively low dose to give a cured layer having excellent surface-releasability so that the composition is useful, for example, as a coating agent of release paper for temporary protection of adhesive surface. The composition comprises (a) 0.1 to 20 parts by weight of a linear organopolysiloxane having at least one vinylphenyl or isopropenylphenyl group bonded to only one of the terminal silicon atoms in the molecular chain and (b) 99.9 to 80 parts by weight of a (meth)acrylate compound which is a (meth)acrylic acid ester of a polyhydric alcohol or a polyester of a polyhydric alcohol and a dibasic carboxylic acid esterified with (meth)acrylic acid at the residual hydroxy groups.

Abstract: A novel silicone-based fabric finishing agent is proposed which is particularly suitable for finishing a fabric material containing keratinous fibers, e.g., wool, for imparting the fabric material with excellent shrink-proofness and soft and pleasant feeling of touch even after repeated laundering treatments. The fabric finishing agent is an aqueous emulsion of a hydroxy-containing organopolysiloxane with admixture of a mixture of colloidal silica and a reaction product of an amino-functional alkoxy silane or a hydrolysis product thereof with an acid anhydride, an epoxy-functional alkoxy silane compound and a curing catalyst.

Abstract: A radiation-curable surface-releasing agent is proposed which is capable of giving surface releasability to a substrate surface by irradiation with electron beams or ultraviolet light exhibiting outstandingly low peeling resistance against peeling of pressure-sensitive adhesive tapes applied and bonded to the release-treated surface and very small migration of the releasing ingredient toward the adhesive surface. The surface-releasing agent is a composition comprising a linear diorganopolysiloxane having, only at one of the molecular chain ends, at least one (meth)acryloxy groups and a poly(meth)acrylate compound such as trimethylol propane tri(meth)acrylate, diethylene glycol di(meth)acrylate, pentaerithritol tri(meth)acrylate and the like.

Abstract: The fabric finishing agent is a solution of a graft copolymer composed of an organopolysiloxane moiety and a grafting moiety thereon obtained by the graft copolymerization of an acrylic or methacrylic monomer, optionally, in combination with monomers of other types. The fabric finishing agent is capable of imparting various kinds of fabric materials with greatly improved soft but non-sticky feeling of touch with resilient elasticity and the effect of treatment is durable and resistant against laundering and dry cleaning.

Abstract: A novel organopolysiloxane compound is proposed which has, in a molecule, at least three (meth)acryloxy groups localized at only one of the molecular chain ends of the polysiloxane chain. By virtue of the localization of the (meth)acryloxy groups, the organopolysiloxane compound is highly curable by the irradiation with a radiation, e.g., electron beams and ultraviolet light, to give a cured coating film on a substrate surface exhibiting excellent releasability against sticky substances. A synthetic route for the preparation of such a one-end crosslinkable organopolysiloxane compound is described.