Abstract: The present invention provides for a two component room temperature vulcanizable silicone compositions wherein both components may be used in approximately equal weights or volumes thereby minimizing the effects of mixture ratio errors.

Abstract: A silicone-based antifoam composition, in the form of an emulsion, is prepared from the reaction of (A) a primary silicone composition and (B) a polydiorganosiloxane having condensable terminal groups in a nonpolar organic medium selected from the group consisting of polyisobutylene and mineral oil. The reaction of the primary silicone composition (A) and the polydiorganosiloxane (B) produces a secondary silicone composition, which forms the discontinuous phase of the emulsion and the nonpolar organic medium forms the continuous phase of the emulsion. The resulting composition of the invention exhibits antifoam efficacy greater than that of the primary silicone composition.

Abstract: The present invention relates to a dispersible silicone composition comprising (I) a silicone composition prepared by reacting (i) a polyorganosiloxane, (ii) a silicon compound, optionally (iii) a finely divided filler, and (iv) a catalytic amount of a compound for promoting the reaction of the other components and (II) mineral oil. The mineral oil is effective as a dispersing agent for the silicone composition (I). The mineral oil-containing compositions are easier to handle, and produce less waste and its dispersion into mineral oil based formulations is more efficient.

Abstract: A coating composition prepared by mixing an organic solvent based coating composition with (1) a silicone compound having organofunctional group and hydrolyzable group in one molecule and containing a specified silicon structural unit, or (2) a silicone compound consisting of a partial cohydrolysis.cndot.condensation product of a silane mixture of alkoxysilane compound containing at least one organofunctional group selected from the group consisting of (meth)acryloyl group, vinyl group, haloalkyl group, amino group, epoxy group and mercapto group with tetraalkoxysilane compound.

Abstract: A curable composition is disclosed and comprises the following components.(A) 100 parts by weight of a oxypropylene polymer having a polymer main chain containing a repeating unit represented by the following formula ##STR1## and having at least one group containing a silicon atom bonded to a hydroxyl group and/or a hydrolyzable group and capable of crosslinking by forming a siloxane bond, wherein Mw/Mn thereof is not more than 1.6 and the number average molecular weight is at least 6,000,(B) from 1 to 200 parts by weight of a filler having a BET specific surface area of not higher than 10 m.sup.2 /g, and(C) from 0.1 to 20 parts by weight of a curing catalyst, said composition containing substantially no plasticizer.

Abstract: A crosslinked polysiloxane dispersion comprising a siloxane polymer, polymer mixture, or polymer/solvent mixture, capable of crosslinking via condensation, addition or free radical reactions, and having a viscosity of greater than 5000 mPa.s but less than 500,000 mPa.s, if required, 0.1 to 10 weight parts of a crosslinking agent, and, if required, depending on the nature of the catalyst and silicon cure system, 0.000001 to 10 weight parts of a catalyst, 0.5 to 10 weight parts of a surfactant or surfactant mixture, and 0.5 to 25 weight parts water per 100 weight parts siloxane polymer. Optionally, adhesion promoters, pigments, reinforcing or non-reinforcing fillers, silicone resins, stabilizers, freeze/thaw additives, etc. may also be added to the dispersion.

Abstract: A sealing compound with a silicone polymer as the base, a cross-linking agent and an accelerator and fillers to be added as needed and a softener, which hardens during contact with the environmental moisture, through addition of heat or through combination of its constituents (2K-products). The softener consists entirely or partially of a paraffinic hydrocarbon, in which the percentage of the cyclical paraffinic hydrocarbons is in the range of 36 to 40% and the percentage of the noncyclical paraffinic hydrocarbons is in the range of 60 to 64%.

Abstract: The present invention relates to a silicone composition prepared by reacting a mixture comprising (i) mineral oil, (ii) a polyorganosiloxane, (iii) a silicon compound, and (iv) a catalytic amount of a catalyst. The compositions of this invention are resistant to phase separation and are useful as foam control compositions in foam producing systems.

Abstract: There is provided an organopolysiloxane composition for electrical insulation wherein the fluidity is good and an inorganic filler deposited on the bottom of a vessel during the storage can be easily and simply redispersed. The unfoamable organopolysiloxane composition for electrical insulation comprises (A) an organopolysiloxane containing at least two alkenyl groups each bonded to a silicon atom in the molecule, (B) an organohydrogenpolysiloxane containing at least two hydrogen atoms each bonded to a silicon atom in the molecule, (C) an organopolysiloxane containing at least one hydroxyl group bonded to a silicon atom in the molecule, (D) an inorganic filler having an average particle diameter of 1 to 50 .mu.m, and (E) platinum or a platinum compound.

Abstract: Novel mixtures containing in the anhydrous state at least one polysiloxane, at least one reactive extender, at least one unreactive pigment and/or an unreactive extender, at least one lamellar or fibrous solid, at least one reactive (oligo)silane, optionally together with further additives, to a production process and to the use thereof.

Abstract: A highly storage-stable room-temperature-curable organopolysiloxane composition that cures to yield a product whose surface resists staining and that does not cause staining of the neighboring regions of the substrate in contact with said cured product. The organopolysiloxane composition is made from a polydiorganosiloxane, an imidazolinyl-functional organosiloxane, a filler, and a crosslinking compound which is a Si-bonded hydrolyzable group-containing organosilane or organosiloxane oligomer.

Abstract: The present invention relates to a silicone foam control composition that is able to inhibit foaming only during the rinse stage without impairing a strong foaming action during the wash stage. The silicone foam control composition comprises 80 to 99 weight % of an organopolysiloxane containing amino-functional or carboxyl-functional organic groups and silica with a specific surface area of at least 50 m.sup.2 /g.

Abstract: The stain resistant cover composition of the present invention for colored rubber part of a tire is characterized by that it comprises water of 100 parts by weight, polyvinyl alcohol of 1.0 to 50 parts by weight, a vinyl acetate resin emulsion of 15 to 150 parts by weight (solid content), a surfactant of 0.5 to 5.0 parts by weight, and a silicon oil of 0.5 to 5.0 parts by weight. The stain resistant protective film of the present invention for colored rubber part of a tire is used as a stain resistant protective film for a colored portion in the side wall part of a tire, wherein the above protective film comprises polyvinyl alcohol, a vinyl acetate resin emulsion, a surfactant, and a silicon oil.

Abstract: Condensation curable silicone mold making compositions containing an olefin or acetylene polymerization inhibitor have a longer useful life for making casts from curable resins comprising a polymerizable olefin relative to compositions where such a polymerization inhibitor is absent. Particularly preferred polymerization inhibitors are the esters of thiodipropionic acid and silicon polysulfides.

Abstract: A method for the preparation of one-package room-temperature-curable silicone compositions that do not slump prior to their cure, do not crack or fissure during their cure even when deformed by an external force, and do not yellow where an example of the room-temperature-curable silicone compositions is(a) hydroxyl-terminated diorganopolysiloxane,(b) oxime-functional organosilicon compound, and(c) inorganic filleraccording to the following four steps:step (1) in which 20 to 70 weight % of the total amount of component (a) is mixed with methyltris(methyl ethyl ketoximo)silane,step (2) in which component (c) is added and mixed into the mixture prepared in step (1),step (3) in which 30 to 80 weight % of the total amount of component (a) is mixed with vinyltris(methyl ethyl ketoximo)-silane,step (4) in which the mixture prepared in step (3) is mixed with the mixture prepared in step (2).

Abstract: The surface-modified fillers according to the invention are manufactured by treating oxidic or siliceous fillers with a silane of the formulaR.sup.1 R.sup.2 R.sup.3 Si--X.sup.1 --(--S.sub.x --Y--).sub.m --(--S.sub.x --X.sup.2 --SiR.sup.1 R.sup.2 R.sup.3).sub.nand are used for the manufacture of rubber vulcanizates, particularly tyres, with reduced dynamic damping and favourable abrasion behaviour.

Abstract: An aqueous silicone emulsion which upon the evaporation of the water forms a surface modified elastomeric silicone material providing improved coverage and adhesion of paint and reduced staining and coefficients of friction, each relative to other silicone elastomers from aqueous emulsions. The silicone emulsion comprises (A) water; (B) a plurality of particles dispersed in the water comprising a crosslinked product of a diorganosiloxane polymer; (C) a surfactant; and (D) an amount of an oxygen curing compound or a salt thereof effective for the surface modification. If a surface active salt of an oxygen curing compound is used, it may not be required to add additional surfactant in order to form the silicone emulsion.

Abstract: The present invention relates to a silicone composition prepared by reacting a mixture of (i) a polyisobutylene compound, (ii) a polyorganosiloxane, (iii) a silicon compound, and (iv) a catalytic amount of a catalyst. The compositions of this invention are resistant to phase separation and are useful as foam control compositions in foam producing systems.

Abstract: Provided are a non-foaming curable silicone elastomer composition and a method of preparing such a composition: with the composition comprising (A) 100 parts by weight of an organopolysiloxane mixture constituted at least of 90-10 parts by weight of organopolysiloxanes (i) containing, in a molecule, at least two alkenyl groups and substantially no silicon-attached hydroxyl group and having their kinematic viscosity in the range of 100 to 100,000 centistokes (cSt) at 25.degree. C. and 10-90 parts by weight of organopolysiloxanes (ii) containing, in a molecule, at least one hydroxyl group attached directly to a silicon atom and at least one alkenyl group attached directly to a silicon atom and having their kinematic viscosity in the range of 100 to 100,000 cSt at 25.degree. C.; (B) organohydrogenpolysiloxanes having in each molecule at least 3 hydrogen atoms attached directly to silicon atoms in an amount that the organohydrogenpolysiloxanes afford 0.4-10.

Abstract: Viscous, liquid hexafluoroisopropanol-siloxane polymers having the basic structure: ##STR1## wherein R.sub.1 is a monovalent hydrocarbon radical selected from the group consisting of C.sub.1 -C.sub.6 alkyl groups; cyclohexyl groups and phenyl groups;R.sub.2 is ##STR2## wherein m=1 to 4; and n is an integer greater than 1, are useful for rapid, reversible vapor sorption, especially for hydrogen bond accepting vapors.

Abstract: A novel silicone system comprising a methoxy terminated silane or polysiloxane, an adhesion promoter and water, useful as a filler alone or in combination with other fillers is disclosed.

Abstract: Storage-stable, alkoxy-crosslinking RTV1 systems that contain carbodiimides as stabilizers.

Abstract: A curable composition includes (A) 100 parts by weight of an oxypropylene polymer having groups containing silicon atoms bonded to a hydroxy group and/or a hydrolyzable group and capable of crosslinking by forming a siloxane bond, a maximum Mw/Mn of 1.6, and an average molecular weight of at least 6,000, (B) from 100 to 200 parts by weight of calcium carbonate containing at least 30% by weight calcium carbonate of an average particle size of not larger than 0.5 .mu.m and surface-treated with a fatty acid, (C) from 30 to 100 parts by weight of a plasticizer containing at least 5% by weight phthalic acid ester plasticizer, (D) from 0.5 to 10 parts by weight of a compound represented by the formula R.sup.1 Si(OCH.sub.3).sub.3 and/or Si(OCH.sub.2 CH.sub.3).sub.4 (wherein R.sup.1 represents a monovalent organic group containing no amino groups), (E) from 0.5 to 10 parts by weight of a compound represented by following formula (1), and (F) from 0.

Abstract: A non-corrosive translucent room temperature vulcanizable silicone composition consists essentially of an alkyl alkoxy stopped diorganopolysiloxane, a polyalkoxysilane crosslinking agent and a tetra alkyl titanate condensation cure catalyst.

Abstract: A process for preparing a room temperature-curable organopolysiloxane composition comprising (A) (A-1) a specific organopolysiloxane or a mixture of (A-1) and (A-2) a specific silicone compound or a partial hydrolysis product thereof, (B) silica powder having a specific surface area of 20 to 800 m.sup.2 /g, (C) a curing catalyst, and (D) a silane coupling agent or an organopolysiloxane having a specific substituent, which comprises adding component (D) to component (A) prior to kneading or at the time of kneading components (A) and (B). The composition exhibits excellent physical characteristics, excellent workability in terms of flowability, adhesion, and extrudability, undergoes no change in viscosity with time and, in particular, suffers no impairment of these characteristics when stored for a long period of time.

Abstract: Oligomers wherein phenylalkylsiloxane units comprise at least a portion of the repeating units increase the ability to penetrate porous substrates that is exhibited by crosslinkable liquid organosiloxane compositions containing polyorganosiloxanes when the oligomer exhibits limited compatibility with the crosslinkable polyorganosiloxane(s) present in the curable organosiloxane composition.

Abstract: A process of making a polydiorganosiloxane-silica foundation mixture from a free-flowing, powdered, surface-modified, reinforcing silica-polydiorganosiloxane concentrate used to make, for example, RTV silicone sealant compositions which have non-sag properties. The foundation mixtures are made by combining, mixing, and heating a reinforcing silica filler and a surface modifying agent to a temperature of >90.degree. C. to <180.degree. C. using 0.1 to 0.5 parts by weight of the surface modifying agent per one part by weight of the silica. Polydiorganosiloxane is added gradually to the resulting fluidized filler over a time period of less than 10 minutes to obtain the free flowing powdered reinforcing silica-polydiorganosiloxane concentrate. The foundation mixture is obtained by massing the concentrate and adding more polydiorganosiloxane to obtain a mixture which has from 8 to 20 weight percent silica filler.

Abstract: A process of making a polydiorganosiloxane-silica foundation mixture from a free-flowing, powdered, surface-modified, reinforcing silica-polydiorganosiloxane concentrate used to make, for example, RTV silicone sealant compositions which have non-sag properties. The foundation mixtures are made by combining, mixing, and heating a reinforcing silica filler and a diol surface modifying agent to a temperature of 20.degree. C. to <180.degree. C. using 0.05 to 0.5 parts by weight of the diol per one part by weight of the silica. Polydiorganosiloxane is added gradually to the resulting fluidized filler over a time period of less than 10 minutes to obtain the free flowing powdered reinforcing silica-polydiorganosiloxane concentrate. The foundation mixture is obtained by massing the concentrate and adding more polydiorganosiloxane to obtain a mixture which has from 5 to 20 weight percent silica filler. The foundation mixtures have a plateau stress of >700 dynes/cm.sup.

Abstract: A composition for in situ treating silica filler is provided, comprising a silanol-terminated, vinyl-containing polydiorganosiloxane which functions both as a processing aid and as a crosslinking agent in vulcanizable fluorosilicone and silicone elastomer compositions.

Abstract: Liquid polysiloxanes are used in defoamant preparations, as diffusion-resistant plasticizer oils, separation agents, or impregnation agents. The liquid polysiloxanes are obtained by reacting:(1) 100 parts by weight of the hydrolysis product of dimethyldichlorosilane having a viscosity of less than 200 mm.sup.2 /sec at 25.degree. C.;(2) 1-100 parts by weight of a polydiorganosiloxane having a viscosity of less than 200 mm.sup.2 /sec at 25.degree. C., of formula (I)R.sup.3.sub.c SiO.sub.(4-c)/2, (I)where each R.sup.3 is independently a substituted or unsubstituted hydrocarbon group with 1-30 carbon atoms, and c has mean value 1.9-3.0; and(3) 0.1-20 parts by weight of one or more compounds (a)-(d),where (a) is a silicon compound of formula (II)R.sup.4.sub.d SiX.sub.(4-d), (II)where R.sup.

Abstract: The present invention includes aqueous coating compositions adapted to coat a plurality of sized glass fibers, glass fibers coated with the same and composites reinforced with the coated glass fibers.

Abstract: A coating composition comprising:a hydrolyzed or partially hydrolyzed alkoxysilane,a solvent,and an arylcyclobutene;is useful in a variety of applications, including coatings for multichip modules, flat panel displays and integrated circuits. The preferred alkoxysilanes correspond to the formula: ##STR1## wherein R is C.sub.1 -C.sub.6 alkylidene, C.sub.1 -C.sub.6 alkylene, arylene, or a direct bond; Y is C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, aryl, 3-methacryloxy, 3-acryloxy, 3-aminoethylamino, or 3-amino; R' is independently in each occurrence C.sub.1 -C.sub.6 alkyl; and Z is C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl or OR'.

Abstract: An aqueous organosiloxane liquid composition in a homogeneous state is disclosed, which contains (A) aqueous modified organosilicon compound having at least one polyether group as a side chain, (B) liquid organopolysiloxane, (C) a cross-linking agent, (D) a curing catalyst and, optionally, (E) a filler. This composition undergoes uniform curing, when exposed to the atmosphere of a temperature of up to 300.degree. C., to form a siloxane polymer composition in a form of a film, fibers, a composite structure, a composite sheet or a building material. The composition can also be used as a coating composition or varnish.

Abstract: The viscosity of a solvent is modified by thickening the solvent with a silicone latex. A silicone latex having a plurality of crosslinked polysiloxane particles is first prepared by mixing the siloxane polymer, a surfactant, and water; emulsifying the mixture to a gel phase; diluting the emulsion with water; adding a cure package (i.e., a catalyst, a crosslinker, or both, or a self catalytic crosslinker); and then without removing the water from the latex and after the particles of siloxane polymer in the latex have been cured, mixing the latex and solvent to thicken the solvent, forming viscous liquids, gels, and pastes. These latex thickened solvent compositions have beneficial properties such as clarity, shelf stability, and ease of preparation; and therefore have wide areas of application, especially as additives in antiperspirants, deodorants, and other personal care applications.

Abstract: The present invention relates to a process for preparing an alkoxy silyl-terminated material, which has at least two alkoxy groups on both terminal ends, said process comprising reacting in the presence of a catalytically effective amount of an organo-lithium reagent an alkoxysilyl-terminated first reactant with a second reactant having both ends of its chain terminating in a silanol. The alkoxy silyl-terminated material may have a variety of polymer backbone types such as silicone, polyurethane, polyamide and the like. These materials are intended to cure by either moisture or photo cure or by dual moisture and photo cure mechanisms. The alkoxy silyl-terminated material is preferably an organopoly-siloxane having at least two alkoxy groups at both terminal ends.

Abstract: The present invention relates to organopolysiloxane-containing compositions which are self-dispersing in water, their preparation and their use. The compositions of the present invention are suitable for all uses where organosilicon compounds, especially in water-diluted form, can be employed. Such uses include uses as water repellant agents on building materials.

Abstract: A room temperature-curable organopolysiloxane composition is disclosed, comprising (A) 100 parts by weight of an organopolysiloxane terminated with a silanol group or an alkoxy group, (B) from 0.1 to 30 parts by weight of an organosilicon compound containing more than 2, in average, of hydrolyzable groups bonded to the silicon atom per molecule, (C) from 1 to 650 parts by weight of an oil-absorbing filler which has been prepared by impregnating (a) a porous filler with (b) a volatile organic compound which is incompatible or partly compatible to component (A) and compatible with an organic oily substance in an amount of from 1% by weight based on the weight of the porous filler up to a saturation amount and, if desired, (D) a requisite amount of a curing catalyst. The composition exhibits satisfactory adhesion to a substrate in such adhesion operation as an FIPG system without requiring wiping of organic oily contaminants on the substrate, such as hydrocarbon oils, e.g.

Abstract: A non-yellowing one-package, RTV, silicone elastomer composition is prepared and has properties such that prior to its cure, it is highly workable and that during its cure does not crack or fissure even when deformed by external force. These one-package, room-temperature-vulcanizable, silicone elastomer compositions comprise (A) diorganopolysiloxane endblocked by oxime group-containing organic radicals where at least 50 mole of the end groups contain alkenyl radicals, (B) oxime group-containing organosilane where no more than 50 mole % of the silane molecules contain alkenyl, and (C) inorganic filler.

Abstract: The process comprises the steps of (A) mixing a base material (A-1), which is obtained by mixing an organopolysiloxane and a reinforcing silica and then heating the resulting mixture, with an aminosilane compound (A-2) represented by the formula:(R.sup.1).sub.n Si[N(R.sup.2).sub.2 ].sub.(4-n)wherein a plurality of R.sup.1 may be the same or different and are each a substituted or unsubstituted monovalent hydrocarbon group, a plurality of R.sup.2 may be the same or different and are each a substituted or unsubstituted monovalent hydrocarbon group, and n is 2 or 3; to allow them to react; and (B) heating the reaction mixture obtained in the step (A) under normal pressure or reduced pressure to remove an unreacted aminosilane compound and a by-product amine, contained in the reaction mixture.

Abstract: A novel photoinitiator which includes an organometallic complex salt grafted onto a polyorganosiloxane skeleton is provided.

Abstract: An aqueous silicone emulsion which yields an elastomer upon removal of the water comprises a polydiorganosiloxane having alkoxysilyl endblocking groups with at least two alkoxy groups attached to the silicon atom, titanium catalyst, and optionally, a filler.

Abstract: The invention comprises processes for the production of useful fluid or grease from curable silicone compositions or silicone rubbers, preferably reclaimed or scrap silicone rubber. The processes involve the application of energy in such a manner that a un-curable silicone grease or liquid that contains essentially all of the original material is produced from curable silicone compositions and grease or liquid is produced from silicone rubbers. Suitable energy forms include thermal and mechanical. The fluid or grease produced by the processes are useful as raw materials for the manufacture of silicone products such as: antifoam compounds (defoamers), greases, conformal coatings or rubbers. The materials produced by these processes were unexpectedly found to have exceptional antifoam properties without requiring the addition of other materials or further processing.

Abstract: This present invention relates to a silicone foam control composition that is able to inhibit foaming only during the rinse stage without impairing a strong foaming action during the wash stage. The silicone foam control composition comprises 80 to 99 weight % of an organopolysiloxane containing amino-functional or carboxyl-functional organic groups and silica with a specific surface area of at least 50 m.sup.2 /g.

Abstract: A room temperature vulcanizable silicone rubber composition with crack resistant properties with improvement during cure, comprising a silanol end-stopped diorganopolysiloxane polymer; a methyl tris-(methyl ethyl ketoximino)silane crosslinker, an aminohydrocarbyl substituted ketoximinosilane adhesion promoter; a reinforcing or non-reinforcing filler or filler mixture, and an optional catalyst and plasticizer. These compositions cure to elastic materials useful as caulking materials, adhesives, coatings and encapsulating materials for the construction and other industries.

Abstract: A composition curable to a silicone elastomer is prepared by mixing a triorganosiloxy endblocked polydimethylsiloxane fluid where the triorganosiloxy is dimethylvinylsiloxy or methylphenylvinylsiloxy, a reinforcing silica having a surface treated with organosiloxane groups which contain 0.05 to 0.32 percent by weight vinyl, a hydroxy end-terminated polydiethylsiloxane fluid, an organohydrogensiloxane fluid, a platinum catalyst, and optionally a platinum catalyst inhibitor. The triorganosiloxy endblocked polydimethylsiloxane fluid has a major peak molecular weight of 68,000 to 135,000, a dispersity index greater than 3.8, the lowest molecular weight species between 854 and 3146 and the highest molecular weight species between 174,000 and 370,000. These compositions are readily extrudable under low pressure, have improved pot-life, cure to high strength elastomers with a high durometer, and have improved mold release.

Abstract: A non-crosslinked endblocked polymer, comprising a preformed aqueous emulsion having a plurality of silanol-terminated polydiorganosiloxane particles, an endcapping silane having the formula R.sub.3 SiX where X is a hydrolyzable group, R is an alkyl group consisting of 1 to 7 carbon atoms, and an organotin catalyst. The composition results in a non-crosslinked polymer, unlike the polymers described in the prior art. It has been found that adding an endblocking silane having only one hydrolyzable group to a preformed polydiorganosiloxane emulsion results in endblocked polydiorganosiloxane molecules free of crosslinks between the polydiorganosiloxane chains.

Abstract: Method for the production of a thermostable crosslinked PVC copolymer where the crosslinking is carried out in the presence of humidity and after processing of the polymer. The copolymer is a copolymer of vinyl chloride and 0.05-10 weight % of a vinyl containing alkoxysilane compound. Preferably methacryloxy-propyltrimethoxy-silane or methacryloxy-propyltriethoxysilane is used as comonomer. The crosslinking can be carried out independent of the type of stabilizer. A condensation catalyst and also an inhibitor can be used to prevent too early crosslinking.

Abstract: Curable silicone compositions comprise either (a) microparticles of a fluororesin which exhibits low adhesion to the cured composition, or (b) microparticles of an organic or inorganic material whose surfaces have been coated with this type of fluororesin. The compositions are useful coatings for semiconductor devices requiring high levels of moisture and heat resistance.

Abstract: A room temperature curable silicone composition, comprising (A) 100 parts by weight of an organopolysiloxane each of both ends of which has one hydroxyl group, (B) 0.2 to 40 parts by weight of at least one compound selected from the group consisting of hydrolyzable silanes having 2 to 4 hydrolyzable groups and their partial hydrolysis-condensation products, (C) 1 to 100 parts by weight of a modified diorganopolysiloxane of which both ends have at least one group selected from the group consisting of a hydrogen atom, a substituted monovalent hydrocarbon group and alkoxy group having 1 to 10 carbon atoms, an unsubstituted hydrocarbon group and alkoxy group having 1 to 10 carbon atoms, and a hydroxyl group and that has a silicon-bonded modifying group made up of a substituted or unsubstituted monovalent organic group with 6 or more carbon atoms, and (D) a filler and a cured product thereof. A cured product good in peeling properties can be obtained.

Abstract: This application is concerned with room temperature vulcanizing compositions useful as mould making materials which are formed by mixing an alpha, omega dihydroxy polysiloxane, a condensation polydimethylsiloxane, catalyst and a crosslinking agent which comprises a tri- or tetra-alkoxy silane or siloxane in which the alkoxy groups contain more than two carbon atoms. Moulds made with these materials on epoxy masters show improved usage; the improvement is related to the size of the alkoxy "leaving group" and the proportion of crosslinker and condensation catalyst.