Abstract: This invention relates to a silicone pressure-sensitive adhesive composition including: (A) a polydiorganosiloxane composed of a linear polydiorganosiloxane (A1) having two or more alkenyl groups within each molecule and a linear polydiorganosiloxane (A2) having SiOH groups at terminals thereof and no alkenyl groups, which is represented by the formula R22(HO)SiO—(R22SiO)d—SiR22(OH), wherein d represents an integer satisfying 500?d?20,000; (B) a polyorganosiloxane including R33SiO1/2 units, SiO2 units and Si atom-bonded hydroxyl group-containing units; (C) a polyorganohydrogensiloxane having three or more SiH groups within each molecule; (D) a reaction retarder; (E) a platinum group metal-based catalyst; and (F) a metal compound represented by formula MYx, wherein the polyorganosiloxane (B) is condensed with the linear polydiorganosiloxane (A2). The composition exhibits powerful adhesive strength to silicone rubbers and is useful for, by example, producing a pressure-sensitive tape.

Abstract: An object of the invention is to provide an optical element for use in an optical information recording and reproducing device or a like device for recording or reproducing information with respect to an information recording medium using laser light, wherein the optical element is a resin optical element capable of suppressing lowering in transmittance due to deterioration by irradiation of light having a high energy density, and maintaining a high transmittance for a long time. To realize the above object, used is an optical element made of a silicon resin cured material obtained by subjecting a silicon resin composition containing a silsesquioxane compound to a curing treatment.

Abstract: Personal care compositions containing pituitous silicone fluids compositions are disclosed. The silicone fluid compositions contain certain branched and/or high molecular weight organopolysiloxanes that demonstrate pituitous rheological behavior. When formulated into personal care compositions, the silicone fluids provide enhanced sensory and film-forming properties based on their pituitous rheological properties.

Abstract: The present invention provides a silicone resin composition for encapsulating light-emitting elements with which encapsulation using a potting method can be easily accomplished, and which can be easily molded into a lens shape such as hemisphere, parabola, or the like. The composition can impart high transparency to the resulting encapsulating lens molded using a potting method. More particularly, the invention provides a silicone resin composition for encapsulating light-emitting elements, including 2 to 25 wt % of silica with a mean particle size of 1 to 30 nm based on the total amount of Components (A) and (B); and having a viscosity (23° C.) of more than 10 Pa·s and less than 70 Pa·s, and a thixotropic index of 2.0 to 5.5; the composition being used for encapsulation using a potting method.

Abstract: A water soluble functional polyethylene glycol-grafted polysiloxane polymer comprising a polysiloxane backbone and polyethylene glycol side chains is provided having the general formula: wherein A is selected from the group consisting of hydrogen, methyl, methoxy and functional polyethylene glycol based chains, B is a functional group for binding biologically-sensitive materials, D is a functional group for binding to a substrate, m is from 3 to 5, v is from 0 to 5, w is from 4 to 11, x is from 0 to 35 and z is from 1 to 33. In order to be water soluble, the polysiloxane polymer h the following properties: x+y+z is from 8 to 40, n is from 8 to 30, and y is from 7 to 35.

Abstract: The present invention relates to a composition for a thermosetting silicone resin, the composition including: (A) an organohydrogenpolysiloxane; (B) an alkenyl group-containing epoxy compound; (C) an alkenyl group-containing cyclic siloxane; and (D) a hydrosilylation catalyst, a thermosetting silicone resin composition obtained by reacting the composition and a production method thereof, a photosemiconductor element-encapsulating material including the thermosetting silicone resin composition, and a photosemiconductor device including a photosemiconductor element encapsulated with the resin composition or the photosemiconductor element-encapsulating material.

Abstract: The present invention relates to hyperbranched copolymer networks containing hyperbranched copolymers that have perfluorocarbon and organosilicon entities that have high hydrophobicity, or high oleophobicity, or high thermal stability, or good adhesion to substrates, or any combinations thereof. This invention provides a further desirable combination of properties that include solubility before crosslinking, chemical resistance, and easy processibility. The copolymers may be crosslinked with a variety of crosslinking agents to give either rigid or elastomeric networks.

Abstract: Crosslinkable compositions containing a crosslinkable organosilicon compound; a silica filler; a silicate or halogen analog thereof, a non-silicate resin-forming monomer; and a solid blowing agent containing intercalated liquid or liquid of crystallization, produce uniform foams of good pore structure, with firm adhesion to substrates, with water repellency and water vapor permeability, and with high elongation and low compression set, and are suitable for use in applications where foamed chloroprene rubber has been used, and in other applications as well.

Abstract: A curable organopolysiloxane composition comprising: (A) a solvent-soluble organopolysiloxane obtained by conducting a hydrosilylation reaction between (i) an organopolysiloxane represented by the following average structural formula: RaSiO(4-a)/2 (wherein R1 represents a substituted or non-substituted monovalent hydrocarbon group, the content of alkenyl groups in all groups represented by R1 is within the range of 0.

Abstract: A silicone resin is obtained by allowing a cage octasilsesquioxane having a group represented by formula (1) below, to react with an alkenyl group-containing polysiloxane containing an alkenyl group having a molarity smaller than the molarity of the hydrosilyl group of the cage octasilsesquioxane in the presence of a hydrosilylation catalyst: (where R1 represents a monovalent hydrocarbon group, R2 represents hydrogen or a monovalent hydrocarbon group, and the molar ratio of monovalent hydrocarbon group: hydrogen in R2 in the cage octasilsesquioxane as a whole is, as an average value, in a range of 6.5:1.5 to 5.5:2.5).

Abstract: The present invention provides an organopolysilmethylene represented by the following general formula (1): wherein R1 is, independently of each other, a group selected from the group consisting of an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group, a hydroxy group, R3SiCH2— and R3SiO—, wherein R is, independently of each other, a group selected from the group consisting of an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group, and a hydroxy group, m is an integer of 1 to 100, and n is an integer of 1 to 100, and wherein at least two out of R1's and R's are an alkenyl group.

Abstract: The present invention provides a hydrophilic silicone which has a predetermined number of silicon atoms and a high purity and is suitable for producing an ophthalmic device and a process for preparing the same. The silicone compound is represented by formula (1) with a purity of 95% by weight or higher, wherein m is one value out of the integers of from 3 to 10, n is one value out of the integers of from 1 to 10, R1 is one out of alkyl groups having 1 to 4 carbon atoms, and R2 is one out of a hydrogen atom and a methyl group.

Abstract: The present invention has an object to provide a polysiloxane which is a liquid substance having low viscosity, is excellent in curing workability, and has excellent heat resistance in an obtained cured material, and to a production method of a cured material using the polysiloxane. Specifically disclosed is a polysiloxane which is obtained by hydrolysis and polycondensation of a silicon compound having three hydrolyzable groups, a silicon compound having two hydrolyzable groups and a silicon compound having one hydrolyzable group, and is characterized by containing a hydrosilylatable carbon-carbon unsaturated group, a hydrosilyl group and an alkoxysilyl group, and having a number average molecular weight of 500 to 20,000.

Abstract: A polymer cures by both radiation and moisture curing mechanisms. The polymer is prepared by hydrosilylation. The polymer is useful in adhesive compositions. The polymer includes units of formulae (I), (R22Si02/2)b, (R2Si03/2)c, (Si04/2)d, (R1)f, and (R23SiO1/2)g, where each R1 is independently an oxygen atom or a divalent hydrocarbon group; each R1 is independently divalent hydrocarbon group; each R2 is independently a monovalent organic group that is free of terminal aliphatic unsaturation each X is independently a monovalent hydrolyzable group; each J is independently a monovalent epoxy functional organic group; subscript a has a value of 1 or more; subscript b has a value of 0 or more; subscript c has a value of 0 or more; subscript d has a value of 0 or more; subscript e has a value of 1 or more; subscript f has a value of 0 or more; subscript g has a value of 0 or more; subscript s is 1, 2, or 3; and subscript t is 1, 2, or 3.

Abstract: A polysilane having excellent functionalities (e.g., solubility in a solvent and reactivity) is obtained by introducing a structural unit of the following formula (1) to a polysilane through a reaction of a dihalosilane having a Si—H bond and adding a hydrosilylatable compound (e.g., a compound having a carbon-carbon unsaturated bond) to the Si—H bond, wherein R1 represents a hydrogen atom, an organic group, or a silyl group; and “n” denotes an integer of not less than 1.

Abstract: Provided is an addition-curable silicone composition including A: a diorganopolysiloxane having a structure represented by a formula (1): (R1)(R2)2SiO((Ar)2SiO)nSi(R2)2(R1) (where R1 represents an aliphatic unsaturated group, R2 represents identical or different, unsubstituted or substituted monovalent hydrocarbon groups, Ar represents identical or different, unsubstituted or substituted aryl groups that may or may not contain a hetero atom, and n represents an integer of 1 or greater), B: an organosilicon compound containing at least two hydrogen atoms bonded to silicon atoms per molecule, and containing no aliphatic unsaturated groups, in an amount that is sufficient to cure the composition in the presence of the hydrosilylation catalyst described below, and C: a platinum group metal-based hydrosilylation catalyst.

Abstract: An adhesive silicone rubber composition comprising (A) 100 pbw of an organopolysiloxane containing at least two silicon-bonded alkenyl radicals, (B) 0.5-20 pbw of an organohydrogenpolysiloxane containing at least two Si—H radicals, (C) a hydrosilylation catalyst, and (D) 0.1-50 pbw of an organosilicon compound having at least one phenyl structure, at least one alicyclic epoxy radical, and at least one Si—H radical is applicable to an electrolyte membrane and a separator in a polymer electrolyte fuel cell to form a firm integrally molded part.

Abstract: A hydrolyzable group-containing organohydrogenpolysiloxane is prepared by (A) reacting (a) an organosiloxane with (b) an organosilane or organosiloxane containing a hydrolyzable group, at least one of components (a) and (b) containing hydrosilyl, in the presence of a superstrong acid catalyst, (B) adding an inorganic basic neutralizing agent and/or an adsorbent to the resulting reaction solution, and (C) removing the neutralized and/or adsorbed form of the superstrong acid catalyst. The process proceeds in an essentially non-aqueous system, and the organohydrogenpolysiloxane free of residual acidic catalyst is obtainable at low cost.

Abstract: The present invention relates to polysiloxane nanoparticles have the following properties: an average particle size d50 (measured using REM recordings) in the range of 10-200 nm, a specific surface area Ao of at least 50 m2/g, a pore volume of at least 0.2 cm3/g, an average pore volume d50 of at least 0.8 mn, whereas the particles have groups that contain carbon, which groups are bonded to the silicon at least partially in the form of unsubstituted or substituted alkyl, alkenyl, aryl, arylalkyl, or alkylaryl groups.

Abstract: A curable aryl siloxane composition is disclosed. A heat stable cured aryl polysiloxane composition is further disclosed, along with a method of making that heat stable cured aryl polysiloxane composition from the curable aryl siloxane composition. An encapsulated semiconductor device, and a method of making that encapsulated semiconductor device by coating a semiconductor element of a semiconductor device with the heat stable cured aryl polysiloxane are further disclosed.

Abstract: The invention provides a process for preparing liquid, branched SiH-functional siloxanes by reacting a mixture of one or more low molecular weight SiH-functional siloxanes, one or more low molecular weight SiH-free siloxanes, one or more tetraalkoxysilanes, and optionally one or more trialkoxysilanes with addition of water and in the presence of a Brønsted-acidic ion exchanger, which is characterized in that the reaction is performed in one process step.

Abstract: Novel epoxy compounds represented by the general formula: (wherein R1 and R2 each represent hydrogen, a C1-6 alkyl group or a C1-4 trialkylsilyl group, each R3 may be the same or different and each independently represents hydrogen, alkyl, aryl, aralkyl, alkenyl or fluoroalkyl, and n is 0 or a positive integer), and the general formula: (wherein R3 represents the same groups specified above, R4 represents hydrogen, a C1-6 alkyl group or a C1-4 trialkylsilyl group, and n is 0 or a positive integer), and a process for their production.

Abstract: A formed article includes a gas barrier layer that is formed of a material including at least an oxygen atom and a silicon atom, a surface area of the gas barrier layer having an oxygen atom content rate of 60 to 75%, a nitrogen atom content rate of 0 to 10%, and a silicon atom content rate of 25 to 35%, based on the total content of oxygen atoms, nitrogen atoms, and silicon atoms, and having a film density of 2.4 to 4.0 g/cm3. A method of producing a formed article includes implanting ions into a surface layer part of a polysilazane compound-containing layer of a formed body that includes the polysilazane compound-containing layer in its surface layer part. An electronic device member includes the formed article. An electronic device includes the electronic device member. The formed article exhibits an excellent gas barrier capability, excellent folding resistance, and excellent transparency.

Abstract: Compositions and methods for controlled polymerization and/or oligomerization of hydrosilanes compounds including those of the general formulae SinH2n and SinH2n+2 as well as alkyl- and arylsilanes, to produce soluble silicon polymers as a precursor to silicon films having low carbon content.

Abstract: Provided is a curable polyorganosiloxane composition which advantageously forms a cured product suitable for LED or optical lens, wherein the cured product has excellent light transmission properties in a short wavelength region, i.e., in the blue to ultraviolet region and is unlikely to suffer yellowing due to exposure to heat.

Abstract: The present invention relates to a perfluoropolyether-modified polysiloxane represented by general formula (1): wherein Rf is a linear or branched perfluoroalkyl group having 1 to 10 carbon atoms; X is a fluorine atom or a trifluoromethyl group; Q is a divalent organic group having 1 to 12 carbon atoms; R1, R2, and R3 are, independently of each other, an alkyl group having 1 to 10 carbon atoms or an aryl group; a, b, c, and d are, independently of each other, an integer of from 0 to 200, provided that a total of a, b, c and d is 1 or larger; e is an integer of 0 or 1; and z is an integer of from 5 to 100; a method for preparing the same; and a defoaming agent comprising the same.

Abstract: A siloxane resin having the formula: (HSiO3/2)a(RSiO3/2)b(SiO4/2)c where R is Z, Z(CH2)n or ZO(CH2)n where Z is a phenyl or substituted phenyl group; n has a value of 1 to 6, a has value of 0.01 to 0.7, b has a value of 0.05 to 0.7, c has a value of 0.1 to 0.9 and a+b+c?1. The siloxane resins are useful in anti-reflective coating compositions.

Abstract: This invention relates to a novel class of Dimer Alkyl Silicone Polymers (DASP) and their use to provide conditioning to skin and hair. By conditioning is meant a elegant smooth skin feel, eliminating dryness and raspiness. It is thought the mechanism of action is related to the fact that the DASP compounds reduce surface tension of personal care products, providing outstanding conditioning and skin feel. The improved conditioning composition based upon a very specific class of dimer alkyl silicone polymers (DASP) that despite their solubility in oil, lower surface tension and improve conditioning of personal care products.

Abstract: Vinylhydrogenpolysiloxanes are provided. The vinylhydrogenpolysiloxanes comprise organopolysiloxanes having at least two silicon-bonded hydrogen atoms and at least two silicon-bonded vinyl groups. As a fraction of the total number of silicon atoms in the vinylhydrogenpolysiloxanes, about 25% to about 90% of the silicon atoms are bonded to a hydrogen atom and about 10% to about 45% are bonded to a vinyl group. The ratio of the number of silicon-bonded hydrogen groups to the number of silicon-bonded vinyl groups is about 1.3 to about 6. Also provided are silicone compositions comprising at least one vinylhydrogenpolysiloxane and a hydrosilylation catalyst; silicone adhesives comprising a cured product of at least one vinylhydrogenpolysiloxane; and laminates comprising at least one such silicone adhesive. When subjected to high temperatures or direct flame, the vinylhydrogenpolysiloxanes form chars that retain adhesion to various substrates.

Abstract: Perfluoropolyether compositions are provided comprising: (A) a linear perfluoropolyether compound containing at least two alkenyl groups, having a perfluoropolyether structure comprising recurring units —CaF2aO— in its backbone, and having a molecular weight of 10,000 to 100,000; (B) an organosilicon compound containing at least two silicon atom-bonded hydrogen atoms; (C) a reinforcing filler; (D) a hydrosilylation catalyst; and (E) a polyfluoromonoalkenyl compound containing one alkenyl group and having a perfluoropolyether structure in its backbone. The compositions cure into rubber or gel products having improved acid resistance.

Abstract: Provided is a heat-conductive silicone composition, including: (A) 100 parts by volume of an organopolysiloxane having a specific structure, (B) 0.1 to 50 parts by volume of an organosilicon compound that functions as a wetter and contains a triorganooxysilyl group bonded to one terminal via an alkylene group that may be branched, (C) 100 to 2,500 parts by volume of a heat-conductive filler, and (D) an effective quantity of a curing agent. Also provided is a heat-conductive silicone cured product obtained by curing this composition. The heat-conductive silicone composition, even when filled with a large quantity of a heat-conductive filler in order to provide superior thermal conductivity, exhibits a minimal increase in viscosity or plasticity, and retains favorable handling properties and moldability. The heat-conductive silicone cured product exhibits excellent flexibility even when filled with a large quantity of a heat-conductive filler.

Abstract: This application relates to polysiloxane compositions grafted with improved heat curable, moisture curable, or heat/moisture curable groups. In particular, the polysiloxane compositions have reactive groups on the terminal or pendent areas of the siloxane backbone, which once reacted provide improved heat and/or moisture curable polysiloxanes.

Abstract: The present invention relates to the use of an adhesive compound, in particular a pressure-sensitive adhesive compound, based on silylated polyurethanes for bonding optical components, in particular optical films, wherein the adhesive compound has a transmission according to ASTM D 1003 of greater than 86% and a haze according to ASTM D 1003 of less than 5%.

Abstract: Gel compositions containing a silicone elastomer from the reaction of an organohydrogensiloxane having at least two SiH containing cyclosiloxane rings in its molecule, a compound having at least two aliphatic unsaturated hydrocarbon groups in its molecule, and a hydrosilylation catalyst. The silicone elastomer reaction product may itself be a gelled composition, or optionally may be contained in a carrier fluid to form a gel. The gel compositions may further contain a personal or healthcare active. The actives may be incorporated into the gel via either a pre or post load method.

Abstract: The present invention relates to a process for the preparation of an organopolysiloxane functionalized with a benzalmalonate by hydrosilylation, said process involving the use of a hydroxy carboxylic acid or a cyclic ester thereof.

Abstract: The invention relates to crosslinkable or crosslinked silicone compositions capable of being used to form a water-repellent and release coating for a flexible support made of paper or of polymer, in particular a heat-sensitive flexible support. These compositions are of the type of those comprising crosslinking polyorganosiloxanes carrying SiH units and unsaturated, preferably vinylated, polyorganosiloxanes capable of reacting with the crosslinking agent by polyaddition in the presence of platinum to form the release crosslinked coating on the flexible support. The targeted aim is to make possible the instantaneous crosslinking at low temperature (85-90° C.) of such silicone compositions coated on flexible supports at a very high speed. To achieve this aim, the invention provides for the use of specific crosslinking agents composed of POSs hydrogenated at the chain end and in the chain.

Abstract: A coating material is described herein that includes at least one inorganic compound, and at least one densifying agent, wherein the densifying agent increases the density of the coating material as compared to the density of the at least one inorganic compound. A method of producing a coating material is described herein that includes: providing at least one inorganic compound, providing at least one densifying agent, combining the at least one inorganic compound with the at least one densifying agent to form the coating material, wherein the densifying agent increases the density of the coating material as compared to the density of the at least one inorganic compound.

Abstract: Disclosed herein is a surface functionalized poly(dimethylsiloxane) (PDMS) and methods for making the same. The surface functionalized PDMS disclosed herein is applicable in the general field of microfluidics, bioMEMS (bio-microelectromechanical systems), soft lithography, and other related biotechnology fields.

Abstract: A thermoset and method of making such by crosslinking a mixture of a polyhedral oligomeric silsesquioxane having pendent siloxane groups or unsaturated carbon bonds and a siloxylcarborane compound having unsaturated carbon bonds.

Abstract: Cyclic dihydrogenpolysiloxanes, hydrogenpolysiloxanes of specific siloxane unit formulas etc., a process for their production using hydrolysis/condensation, a process for the production of silica type glass moldings with an optical transmittance of 90% to 100% in the vacuum-UV region to UV region and an optical transmittance of 98% to 100% in the visible region to near infrared region by curing said cyclic dihydrogensiloxanes or said hydrogenpolysiloxanes in a mold, said silica type glass moldings, optical elements made up of the silica type glass, a process for the production of optical elements having such a silica type glass film layer by coating an optical element with the hydrogenpolysiloxanes and curing them, and optical elements having such a silica type glass film layer.

Abstract: A method of preparing a reinforced silicone resin film, the method comprising the steps of impregnating a fiber reinforcement in a hydrosilylation-curable silicone composition comprising a silicone resin, and heating the impregnated fiber reinforcement at a temperature sufficient to cure the silicone resin, wherein the reinforced silicone resin film comprises from 10 to 99% (w/w) of the cured silicone resin and the film has a thickness of from 15 to 500 ?m; and a reinforced silicone resin film prepared according to the method.

Abstract: Silicone composites subject to reticulation or reticulated, particularly for creating a coating or water-repellent and anti-adhesive film for flexible substrates such as paper or similar in the form of natural or synthetic polymer films. These compounds contain reticulating polyorganosiloxanes that have SiH units and unsaturated polyorganosiloxanes, preferably vinylated, suitable for reacting with the reticulating agent in an addition reaction and in the presence of platinum to form the reticulated anti-adhesive coating on the flexible substrate, plus at least one additive (D) to promote adhesion to it.

Abstract: A resist composition comprising (A) a hydrogen silsesquioxane resin, (B) an acid dissociable group-containing compound, (C) a photo-acid generator, (D) an organic solvent and optionally (E) additives. The resist composition has improved lithographic properties (such as high etch-resistance, transparency, resolution, sensitivity, focus latitude, line edge roughness, and adhesion) suitable as a photoresist.

Abstract: Mixtures of silicone resin with an organopolysiloxane copolymer prepared by hydrosilylating a substantially linear polymer containing an isocyanate reactive group with an Si—H containing organopolysiloxane, and reacting this intermediate with a diisocyanate, are useful as long lasting defoamers which are compatible with numerous media.

Abstract: Silicone polyethers are prepared in a two stage process by reacting an unsaturated polyether with a first Si—H functional organopolysiloxane and then with a second organopolysiloxane, in which the weight ratio of silicon bonded hydrogen in the first and second organopolysiloxanes is at least 0.9. The reaction is more rapid than a single step process and produces a product with less unreacted Si—H content.

Abstract: A method for producing hydrogen (H2) includes the steps consisting in: a) reacting a compound (C) including one or more groups Si—H with a fluoride ions source, thereby forming hydrogen and a by-product (C1); and b) recovering the obtained hydrogen.

Abstract: An adhesive containing a ladder-type polysilsesquioxane which firmly bonds metals and synthetic resins and an adhesive sheet having an adhesive layer formed by using the adhesive on at least one side of a substrate are provided. An adhesive comprises a ladder-type polysilsesquioxane having a recurring unit of the following formula (I) in the molecule, wherein R1 represents a polymerizable functional group, and R2 represents the same group as R1, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an alkoxy group having 1 to 6 carbon atoms which may have a substituent, or a phenyl group which may have a substituent, and the adhesive sheet has an adhesive layer formed by using the adhesive on at least one side of the substrate.

Abstract: A curable silicone gel composition that is of low viscosity, exhibits good fluidity, and generates a silicone gel that exhibits good resistance to external stress and thermal stress. The composition includes (A) a specific organopolysiloxane having at least two alkenyl groups within each molecule, (B) an organohydrogenpolysiloxane having a specific branched main chain structure, containing at least three SiH groups within each molecule, and also containing at least one branch-forming unit within each molecule, and (C) a platinum-based catalyst, wherein the cured product has a penetration value of 10 to 200, and loss coefficient values at 25° C. for shear frequency values of 1 Hz and 10 Hz of 0.1 to 1.0 and 0.3 to 1.5 respectively.

Abstract: Use of release fluids or agents constituting hyperbranched polymers. The three-dimensional structure imparts characteristics that make the hyperbranched polymers useful in xerographic processes. The hyperbranched polymer release fluids or agents may be used with a fuser member having a substrate, an outer layer covering the substrate, and a release coating on the outer layer, wherein the release coating includes a hyperbranched polymer.

Abstract: An addition-curable silicone composition is provided. The composition includes (A) a resin structure organopolysiloxane and (B) a platinum group metal-based catalyst. The component (A) has silicon-bonded alkenyl groups and hydrosilyl groups, and includes a structure in which R22SiO units, wherein R2 is a methyl group, etc., are connected together in a continuous repeating sequence, and the number of units in the continuous repeating sequence is within a range from 5 to 300. The composition can be prepared in a solid or semisolid form, and hence is suitable conventional molding apparatus such as a transfer molding apparatus, and upon curing, forms a hard resin cured product that exhibits excellent flexibility and minimal surface tack.