Abstract: Reaction resin mixtures which can be economically processed provide inflammable molded materials with excellent mechanical properties and high dimensional stability under heat when they contain the following constituents: (A) a phosphorus-free polyfunctional epoxide; (B) an epoxy-group-containing phosphorus compound; (C) a polyfunctional isocyanate; (D) a curing catalyst; and, if required, (E) filler material.

Abstract: Single-component diorganopolysiloxane compositions, stable in storage in the absence of atmospheric moisture and crosslinkable into elastomeric state in the presence of moisture, well adapted, e.g., as sealants and adhesives for the construction industry, contain (A) a diorganopolysiloxane polymer having silanol endgroups, (B) a ketiminoxysilane crosslinking agent, (C) a stabilizing amount of an isocyanurate of the formula: ##STR1## (D) an inorganic filler material, and (E) a metal curing catalyst.

Abstract: Curable silicone caulk compositions are provided using a nonionically stabilized silanol-terminated polydiorganosiloxane, water, a silane cross-linker, a tin condensation catalyst, and calcium carbonate.

Abstract: A self-leveling silicone composition, which is useful as a sealant in contact with asphalt, cures upon exposure to moisture in the atmosphere to an elastomer having an elongation of at least 1200 percent, and a modulus at both 50 and 100 percent elongation of less than 25 pounds per square inch. The composition consists essentially of a hydroxyl endblocked polydiorganosiloxane, non-acidic, non-reinforcing treated filler, diacetamido functional silane, aminoxysilicon crosslinking compound, and non-reactive silicone fluid diluent.

Abstract: A process for preparing an antirust composition is described, particularly for underbody and already painted and finished motor vehicle parts, having improved physical and mechanical properties, which comprises: (1) preparing a reaction mixture obtained by mixing a preformed product containing an emulsifier, an organic diluent and an inorganic carbonate, with one or more monomers, water and a radicalic catalyst, (2) heating the mixture thus obtained to polymerize the monomer, and (3) further heating to vaporize water, optionally under vacuum, the polymer being formed in situ in the basic gelified composition. A method to provide better rust strength to painted parts or surfaces using the composition thus prepared is also described.

Abstract: Organopolysiloxane compositions that are storage-stable under anhydrous conditions, but curable into elastomeric state in the presence of moisture and, thus, are well suited as sealants and coatings and which particularly strongly adhere to substrates used in the construction industry, contain at least one .alpha., .omega.-dihydroxydiorganopolysiloxane polymer; at least one ketiminoxysilane crosslinking agent therefor; a bonding agent including admixture, or reaction product of, (i) an aminoorganosilicon compound containing a primary amine group, with (ii) an organosilicon compound containing an epoxy functional group; and, advantageously, a filler material and a curing catalyst.

Abstract: Polydiorganosiloxane compositions which are stable in storage with exclusion of moisture and which are curable with water or atmospheric air are useful to produce paintable joint sealing compounds and coating composition and the composition is a mixture of .alpha., .omega.-dihydroxy-polydiorganosiloxanes, carboxylic acid amido alkylalkoxy silicon compounds as cross-linking agents, complex titanic acid esters and filler which comprises a precipitated, hydrophobicized chalk whose residual moisture has been removed before contact with the titanic acid esters and cross-linking agents in the mixture.

Abstract: A silicone composition which is stable in the absence of moisture, but cures to an elastomer upon exposure to moisture consists essentially of a hydroxyl endblocked polydiorganosiloxane; a difunctionalsilane having acetamido, urea, or urethane functional groups; and a tetrafunctionalsilane having oximino functional groups. A composition containing 100 parts by weight of the polydiorganosiloxane, from 0.1 to 7 parts by weight of difunctionalsilane, from 0.1 to 7 parts by weight of tetrafunctionalsilane, and a ratio of difunctionalsilane to tetrafunctionalsilane of from 0.1 to 3, and optional filler is useful as a sealant or adhesive, having an improved skin over time.

Abstract: Organopolysiloxane compositions that are storage-stable under anhydrous conditions, but curable into elastomeric state in the presence of moisture and, thus, are well suited as sealants and coatings and which particularly strongly adhere to substrate used in the construction industry, contain at least one .alpha., .omega.-dihydroxydiorganopolysiloxane polymer; at least one acyloxysilane crosslinking agent therefor; a bonding agent including admixture, or reaction product of, (i) an aminoorganosilicon compound containing a primary amine group, with (ii) an organosilicon compound containing an epoxy functional group; and, advantageously, a filler material and a curing catalyst.

Abstract: The pumpability and extrudability of a mixture of linear polymer and filler can be controlled by using a mixture of filler particle sizes. For 100 parts by weight of polymer there is mixed in from 50 to 150 parts by weight of filler mixture, the filler mixture comprising from 0.5 to 50 percent by weight of a large particle size filler having an average particle diameter of from 0.5 to 10 micrometers and from 50 to 99.5 percent by weight of a small particle size filler having an average particle diameter of less than 0.1 micrometers, the large particle size filler having an average particle diameter of at least 10 times the average particle diameter of the small particle size filler. By adjusting the ratio of large particle size filler to small particle size filler, the change in viscosity of the mixture with change in temperature can be controlled.

Abstract: The specification describes and claims curable polysiloxane compositions filled with a mixture of two types of finely divided calcium carbonate. The curable polysiloxane comprises 100 parts by weight of a hydroxypolysiloxane with from 5 to 12 parts by weight of a curing agent therefore comprising a silane of the formula R.sub.a R'.sub.b Si or a siloxane having units ##EQU1## wherein each R represents a monovalent hydrocarbon group, each R' represents an hydroxy, alkoxy, or alkoxyalkoxy group, a+b=4, a has a value 0 or 1, b has a value 3 or 4, c has a value 1, 2 or 3 and a+c is not greater than 3 as exemplified by methyl trimethoxy silane, together with a catalytic amount of a titanium or tin compound for promoting curing of the product in presence of moisture of the atmosphere.

Abstract: A moisture curable solventless organopolysiloxane composition is provided useful as an adherent construction sealant. Improved cure rate, higher elongation at break values and lower modulus RTVs are achieved by using a bis(ureido)silane as a coupler and an aminoxysiloxane as a crosslinker for a silanol-terminated polydiorganosiloxane base polymer.

Abstract: Polyorganosiloxane compositions which can be stored in the absence of moisture and which harden rapidly in the presence of moisture, comprising a mixture of(1) 100 parts by weight of an .alpha.,.omega.-dihydroxypolydimethylsiloxane having a viscosity of from 0.1 to 1000 Pas,(2) 0 to 100 parts by weight of an .alpha.,.omega.-bis-(trimethylsiloxy)-polydimethylsiloxane having a viscosity of from 0.04 to 10 Pas as plasticizer,(3) 1 to 10 parts by weight of an oximinosilane corresponding to the following formula ##STR1## in which R preresents C.sub.1 -C.sub.4 alkyl or alkenyl radicals,R.sup.1 and R.sup.2 each represent a C.sub.1 -C.sub.4 alkyl radical or hydrogen or R.sup.1 and R.sup.2 together represent a C.sub.4 or C.sub.5 alkylene radical and a may assume the value 0 or 1,(4) 5 to 250 parts by weight of a reinforcing or non-reinforcing filler of filler mixture,(5) 0 to 2.

Abstract: The printability of paper is improved by applying an aqueous coating agent consisting of(a) 100 parts by weight of a finely divided pigment,(b) from 5 to 70 parts by weight, based on solids, of a cationic aqueous polymer dispersion of a paper size and(c) from 0.01 to 10 parts by weight of a surfactant which interferes with the formation of the surface size and/or of a polymeric dispersantin an amount of from 0.5 to 4 g/m.sup.2 to one or both surfaces of the paper and drying the coated paper.

Abstract: A one-part curing composition comprising a compound (a) having two or more structural groups, per molecule, expressed by the general formula: ##STR1## wherein R.sup.1, R.sup.2, and R.sup.3 are groups selected from an alkyl group having 1 to 6 carbon atoms, a phenyl group, and a chloromethyl group, and a polymer (b) having two or more isocyanate groups per molecule, has a good stability in storage under conditions which exclude moisture and humidity, and which further cures in the presence of humidity. This composition does not foam under high temperatures and humidities and has a good heat resistance.

Abstract: A silicone sealant which is stable in the absence of moisture and cures upon exposure to moisture to give an elastomer with a controllable modulus is produced by mixing a polydiorganosiloxane having both vinyl and alkoxysilethylene endblocking, alkoxy silane crosslinker, titanium catalyst, and optional filler. The modulus is controlled by varying the ratio of vinyl to alkoxysilethylene endblocking present on the polymer.

Abstract: An addition or condensation cross-linking molding or lining compound based on silicones comprising(a) an organo polysiloxane containing reactive end groups,(b) a catalyst,(c) a filler, and(d) an isoparaffin having 8 to 24 carbon atoms.The compounds being particularly useful as dental molding compositions.

Abstract: A moisture curable composition which is useful for sealing pavement joints consists essentially of 100 parts by weight of a hydroxyl endblocked polydiorganosiloxane, 55 to 120 parts of non-reinforcing, non-acidic filler wherein at least 40 percent by weight of the filler is treated with calcium stearate, 2.5 to 10 parts of diacetamidosilane, and 1 to 6 parts of aminoxysilicone compound. The composition is self leveling when applied to a horizontal surface and when cured has an elongation of at least 1200 percent, a durometer on the Shore OO scale of from 45 to 75 inclusive, and a modulus at 150 percent elongation of less than 50 pounds per square inch.

Abstract: Curable silicon caulking compositions are provided having improved shelf stability as a result of the use of a neopentyl orthosilicate.

Abstract: A process for producing a silicone sealant which is stable in the absence of moisture and having a slump of less than 1 inch mixes a polydiorganosiloxane polymer having hydroxyl or alkoxysilethylene endblocking, an alkoxysilane crosslinker, and a titanium catalyst; then adds a reinforcing filler.

Abstract: This invention relates to .beta.-amino-.beta.-propiolactam derivativatives, moisture curable polyurethane compositions and their applications.The products of this invention have excellent characteristics such as good storage stability, rapid curing with atmospheric moisture and freedom from foaming.More particularly, condensed compounds are obtained by reacting specific secondary diamines such as piperazine and 1,3-(4,4'-dipiperidyl)propane with monoaldehyde having at least 3 carbon atoms, for example, isobutylaldehyde and .beta.-phenylpropylaldehyde. The .beta.-amino-.beta.-propiolactam derivatives are prepared by reacting the condensed compounds with monoisocyanate such as phenyl isocyanate and equimolar reaction products of diisocyanate with lower monohydric alcohol.In addition, the moisture curable polyurethane compositions contain said derivatives and polyisocyanate and/or polyurethane prepolymer having terminal isocyanato radicals.

Abstract: Certain bissilyl ureas have been found useful as adhesion promoters for silicone latex compositions. Self-bonding silicone elastomers are provided which exhibit enhanced adhesion to a variety of substrates.

Abstract: A polyether having molecular weight from 1,000 to 50,000, end-blocked with hydrolyzable silyl groups and represented by the general formula (P): ##STR1## where R.sup.1, R.sup.2, R.sup.6 and R.sup.7 individually represent a divalent hydrocarbon group, R.sup.4 represents a monovalent hydrocarbon group, R.sup.8 represents an alkyl group with 1 to 6 carbon atoms, a represents a number from 1 to 3, m represents a number from 10 to 500, n represents a number of 1 or greater and --N.dbd.X.dbd.N-- represents a residue group of a diimino heterocyclic compound, from which nitrogen-bonded hydrogen atoms are eliminated, said diimino heterocyclic compound having no ##STR2## bond in a molecule is produced and utilized in room temperature curing compositions containing inorganic filler and curing catalyst. There is also disclosed a method for producing the above polyether by reacting polyoxyalkylene end-blocked with epoxy groups, diimino heterocyclic compound and organo silicon compound.

Abstract: Polysiloxane compositions which harden in the presence of moisture by elimination of alcohols, which have high stability in storage while unvulcanized in the absence of moisture, which exhibit good adhesion to substrates, and which are improved by the presence of stabilizing silyl derivations of N-methyl benzamide contain:(A) 100 parts by weight of a polydimethyl siloxane which contains terminal diorganyloxyorganosilyl or triorganyloxylsilyl groups and which has a viscosity of 0.1 to 100 Pas,(B) 0 to 100 parts by weight of an .alpha.,.omega.-bis(trimethylsiloxy)-polydimethyl siloxane which has a viscosity of from 0.04 to 10 Pas,(C) 0 to 5 parts by weight of an alkoxysilane having the formulaR.sup.1.sub.a Si(OR.sup.2).sub.4-a,in whichR.sup.1 is C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl or C.sub.5 -C.sub.6 aryl;R.sup.2 is C.sub.1 -C.sub.6 alkyl, and a is 0 or 1,(D) 0.

Abstract: Suspension polymerization a vinyl monomer in the presence of from about 0.01 to 2.0%, by weight of the total monomer content, of a carboxymethyl hydrophobically modified water-soluble, nonionic cellulose either polymer alone or in combination with an inert electrolyte or inert polyelectrolyte is disclosed. The presence of the carboxymethyl hydrophobically modified water-soluble, nonionic cellulose ether polymer alone or in combination with an inert electrolyte or inert polyelectrolyte provides suspension polymer beads of narrower polydispersity and clarity, and results in minimal latex polymer (emulsion polymer) by-products.

Abstract: Polyalkoxysilyl-terminated polydiorganosiloxanes which are relatively stable in viscosity over prolonged storage periods are prepared by endcapping a silanol-terminated polydiorganosiloxane in the presence of a catalytic amount of an acidic amine salt which subsequently decomposes to substantially inert products, preferably an amine salt of formic acid, and in the absence of silicon-nitrogen compounds and enoxysilanes normally used as catalyst quenchers and scavengers. The products are useful for the preparation of scavenger-free room temperature vulcanizable compositions, particularly when combined with certain N-alkoxy-silylalkyl-substituted compounds as adhesion promoters.

Abstract: A process for preparing an antirust composition is described, particularly for underbody and already painted and finished motor vehicle parts, having improved physical and mechanical properties, which comprises:(1) preparing a reaction mixture obtained by mixing a preformed product containing an emulsifier, an organic diluent and an inorganic carbonate, with one or more monomers, water and a radicalic catalyst, (2) heating the mixture thus obtained to polymerize the monomer, and (3) further heating to vaporize water, optionally under vacuum, the polymer being formed in situ in the basic gelified composition. A method to provide better rust strength to painted parts or surfaces using the composition thus prepared is also described.

Abstract: Novel polyurethane formulations especially useful as membranes of the protection of bridge deckings. The polyurethane is prepared by mixing two components, A and B. Component A comprises castor oil modified with a ketone-formaldehyde condensate and also preferably contains an elastomer. Component B is a modified MDI, being a mixture of diphenylmethane diisocyanate and its reaction product with a low molecular weight poly(oxyalkylene).

Abstract: The present invention relates to a process for the production of storable thermosetting polyurethane-polyurea compositions wherein a storable isocyanate component stabilized by a surface coating and a polyol and/or polyamine component are separately prepared. A one-component polyurethane-polyurea reactive mixture is formed by mixing just before the intended use the separate components under mild shear forces at a temperature below the thickening temperature of the final reactive mixture.

Abstract: Disclosed is an improved method for making a thermoset polymer wherein a plurality of reactant streams, one of which contains the activator of a metathesis catalyst system combined with a moderator, and a second of which contains the catalyst of the metathesis catalyst system and at least one of which contains dicyclopentadiene are combined to form a reaction mixture, and the reaction mixture is then injected into a mold where polymerization occurs. The improvement comprises adding to the reaction mixture 1-25 mols of a cationic polymerization initiator per 1000 mols of dicyclopentadiene.

Abstract: Rubber based adhesives containing liquid stereospecific polybutadiene rubber, one or more hardeners or hardener systems, fillers and optionally primers, which contain one or more chemically irreversibly depolymerized solid rubbers of natural or synthetic origin in quantities of from 1.5 to 5% by weight, based on the sum of the constituents, to a process for the production of these low-viscosity rubber-based adhesives by chemically irreversible depolymerization of one or more solid rubbers of natural or synthetic origin, and to the use of these low-viscosity rubber-based adhesives in the bonding of metal components in automotive manufacturing.

Abstract: A silicone sealant composition which bonds to dolomite containing concrete after exposure to moisture is obtained by adding a silicone fluid having greater than 2 mole percent epoxy functionality to a sealant of the type containing a hydroxyl endblocked polydiorganosiloxane, acetamidosilane chain extender, and crosslinking agent selected from the group consisting of triacetamidosilane and aminoxysilicon compound.

Abstract: An adhesive composition comprising (1) a polymetallocarbosilane or a polycarbosilane and (2) a silicone resin. The adhesive composition further comprises an inorganic filler.

Abstract: Heat-vulcanizable organopolysiloxane compositions, adopted for curing into silicone elastomers having improved reversion and oil resistance and useful, e.g., as seals in contact with hot oils, comprise at least one diorganopolysiloxane resin (A) having a viscosity of greater than 1,000,000 mPa.s at 25.degree. C., a reinforcing and/or semireinforcing filler material (B), an organic peroxide (C), an organosilicon compound (D) containing at least one acryloyloxyalkyl or methacryloyloxyalkyl group bonded to a silicon atom, and (E) at least one oxide or hydroxide of an alkaline earth metal.

Abstract: The water permeability of cured thermosetting organic resin compositions is reduced and the dimensional stability of these compositions during molding is improved by the addition to the curable resin composition of a finely divided, cured organosiloxane material prepared from a curable organopolysiloxane, a curing agent for the organopolysiloxane, an optional silica filler and an aromatic hydrocarbon compound containing a substituted benzene ring where the substituent is a monovalent ethylenically unsaturated hydrocarbon radical or an alkenyloxy radical.

Abstract: A one-component adhesive and/or sealing mass which is stable and pumpable at temperatures up to 30.degree. C. containsat least one prepolymer on the basis of a polyurethane, which contains from 0.1 to 15 percent by weight, referred to the prepolymer, of free, reactive isocyanate groups, andat least one with heat activatable hardener.Thereby the stoichiometric ratio between said prepolymer and said hardener is chosen in such a way that only a partial cross-linkage is possible during heating said mass to temperatures from 60.degree. C. to 180.degree. C., and that a product is obtained having from high viscous to plastic characteristics.The inventive masses may be used for bonding and/or sealing of one or more materials of the same or different origin to a composite.

Abstract: A curable silicone coating composition which is resistant to dirt pickup, comprising:(1) a vinyl chainstopped polysiloxane having a viscosity up to 2,000,000 centipoise;(2) 1 to 2 parts of a resinous organopolysiloxane copolymer per part of (1);(3) a platinum catalyst and,(4) an organohydrogenpolysiloxane crosslinking agent.

Abstract: An auto-adhering one-component room temperature vulcanizable silicone sealant composition generally utilizing a di-substituted mixed oxime-alkoxysilyalkyl area adhesion promoter compound. The sealant has low odor, is non-corrosive to ferrous or aluminum substrates, has good adhesion to many types of substrates, and eliminates the need for a silicone resin primer. In addition, it exhibits surprisingly good adhesion to oil contaminated surfaces.

Abstract: A curable composition comprising (A) a monomer mixture containing as an essential component thereof a mixture of 20 to 80% by weight of an aliphatic polyfunctional (meth)acrylate and 80 to 20% by weight of an aromatic vinyl compound, (B) an inorganic filler having an average particle diameter of not more than 5 microns, and (C) a catalytic amount of a polymerization initiator, and having said inorganic filler (B) dispersed in an amount of 250 to 800 parts by weight per 100 parts by weight of said monomer mixture (A).

Abstract: A process for the preparation of triorganooxysilyl- or diorganooxyorganosilyl-terminated poly(diorganosiloxanes) or formulations containing such siloxanes comprising reacting .alpha.,.omega.-dihydroxypoly(diorganosiloxanes) with tetraorganyloxysilanes or triorganyloxyorganosilanes in the presence of an ammonium carbamate catalyst of the formula I ##STR1## wherein, R represents a hydrocarbon radical with 1-20 C atoms or an H atom, and where identical or different R radicals are in the molecule.The products produced by this process can be employed in the preparation of one-component silicone paste which harden into elastomers in the presence of moisture.

Abstract: The present invention produces a silicone polymer-filler mixture by passing prescribed quantities of silicone oligomer, filler and polymerization catalyst through a continuous kneader extruder with kneading and polymerization of the silicone oligomer into silicone polymer. A homogeneous silicone polymer-filler mixture is rapidly produced in a single process with low energy consumption.The silicone polymer-filler mixture produced by the present method is useful as a base for diverse silicone rubber compositions, silicone compounds and silicone greases, etc.

Abstract: Room temperature-curable organopolysiloxane compositions are made from essentially linear organopolysiloxanes having hydroxyl or hydrolyzable end groups, a crosslinking agent, a filler, optionally a curing catalyst, an unsaturated ester having at least ten carbon atoms in the unsaturated fatty acid component of the ester, and a photosensitizer. These compositions cure to elastomeric materials which do not soil on the surface or the surrounding areas of the substrate in contact with the cure product. The adhesion of these cured products is not reduced.

Abstract: A composition for artificial marble which comprises a polymer composition in which an inorganic substance and an organic polymer are firmly bound in one body and a vinyl compound, said polymer composition being obtained by polymerizing a polymerizable vinyl monomer, in the presence of at least one monomer selected from the group consisting of carboxylic acid monomer, sulfonic acid monomer, and sulfonate monomer, in an aqueous polymerization system containing an inorganic substance dispersed therein; and a processs for producing artificial marble from said composition by cast polymerization with the addition of a polymerization initiator.

Abstract: This invention relates to oil-in-oil emulsions wherein the continuous phase comprises at least one carboxyalkyl terminated polydiorganosiloxane and the dispersed phase comprises at least one epoxide compound selected from diglycidyl ethers of di- and bis-phenols. The emulsions also include a curing catalyst in addition to an dispersing agent for the epoxide compound, and can be cured with heating to form elastomeric materials exhibiting properties characteristics of silicone rubber.

Abstract: An aqueous silicone elastomeric emulsion is a storage stable, paste-type material useful as a caulking material. The caulking material is obtained by mixing an anionic emulsion containing dispersed particles of hydroxyl endblocked polydiorganosiloxane, dialkyltindicarboxylate, silane of the formula RSi(OR').sub.3 where R is a monovalent hydrocarbon radical of from 1 to 4 carbon atoms inclusive and R' is a lower alkyl radical of from 1 to 4 carbon atoms inclusive or a radical of the formula --N.dbd.CR.sub.2, and inert, non-siliceous filler.

Abstract: The room temperature-curable (RTV) organopolysiloxane composition of the invention comprises, in addition to the conventional components of a diorganopolysiloxane terminated at both molecular chain ends each with a silanolic hydroxy group, a hydrolyzable organosilicon compound having two or more hydrolyzable groups in a molecule and a filler, an organosilicon-modified polyoxyalkylene compound, of which the organosilicon-containing terminal groups have at least one hydrolyzable group so as to pertain to the crosslinking reaction in its part. By virtue of this unique additive component, the composition is quite free from the disadvantage of sagging when the composition is applied to building works and the like and still retains excellent adhesive properties to the substrate surface in contrast to the difficulty in the conventional RTV compositions in which reducing of the phenomenon of sagging and retention of the strong adhesive strength are hardly compatible.

Abstract: A molding composition is provided comprising aromatic vinyl ether and maleimide. The cured composition exhibits high heat distortion temperatures and is easily processed into finished products with or without a catalyst.

Abstract: A silicone caulking material obtained by mixing an anionically stabilized, hydroxyl endblocked polydiorganosiloxane in an aqueous emulsion, dialkyltindicarboxylate, alkylorthosilicate, and inert, non-siliceous filler is capable of yielding an elastomer upon removal of the water immediately upon mixing of the ingredients. When the caulking material also contains 2-amino-2-methyl-1-propanol, the emulsion also has a useful shelf life in that the emulsion shows no gelation upon aging. The physical properties of the elastomer produced by removing the water from the emulsion do not change appreciably during the useful life of the caulking material.

Abstract: An adhesive composition for filling gaps and sealing joints in engineering assembly comprises a blend of 100 parts by weight of a liquid polybutadiene polymer having an average molecular weight from 1,000 and a viscosity from 2 to 800 dPas at 25.degree. C., at least 40 percent of the unsaturation having a 1,4 configuration, preferably cis 1,4; 5 to 60 parts of powdered sulphur; 2.5 to 70 parts of an organic accelerator or accelerators; and up to 80 percent by weight of an inert filler or fillers. The adhesive composition may also include promoters, dessicants, blowing agents and/or solid rubber, preferably solid polybutadiene.

Abstract: Peroxide curable organosiloxane elastomer compositions where from 0.1 to 10 mole percent of the silicon-bonded hydrocarbon radicals are phenyl improve the leakage current resistance of silicon diodes when the compositions are applied to these devices as junction coatings.