Abstract: Room temperature vulcanizable, scavenger-reduced, organopolysiloxane compositions having improved application rate amd thixotropy properties are provided, comprising a mixture comprising (A) the reaction product of a polyalkoxy-terminated organopolysiloxane, silica filler, and a cyano-functional polyalkoxy silane; (B) a tin condensation catalyst; and (C) a scavenger for hydroxy groups. In preferred embodiments, the RTV composition further comprises a crosslinking polyalkoxy silane and an adhesion promoting polyalkoxysilane.

Abstract: A method of preparing pure 3-butenyl triorgano oxysilanes, the intermediate products 3,4-dichlorobutyl triorgano oxysilanes and the use of the final products in rubber mixtures reinforced with silicic acid and vulcanizable with peroxides. 3,4-dichlorobutene-1 and trichlorosilane are used as initial products.

Abstract: A hard coating composition comprising an epoxy group-containing organic silicon compound and inorganic submicron particles such as silica sol is curable with a minimal amount of an antimony compound as the curing catalyst. The composition is thus stable during shelf storage and can be cured to a plastic optical article as a mar resistant hard coating film.

Abstract: The emulsion polymerization of a mixture of organic silicon monomers and vinyl containing organic monomer is effected substantially concurrently. Flocculation of the emulsion polymerized material, and recovery of the flocculated material has been found useful in providing multi-lobed impact modifiers for a variety of organic thermoplastic polymers.

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 room temperature-curable composition comprising (A) a silanol-terminated polydiorganosiloxane having a viscosity measured at 25.degree. C. of from 100 to 200,000 cSt, (B) an epoxy-terminated polyether, (C) an organosilicon compound, (D) an inorganic filler, and (E) a curing catalyst. The composition is suitably used as a building sealant which causes no fouling of the areas surrounding joints even after applied to the joints.

Abstract: A room temperature-curable organopolysiloxane composition, which is capable of giving a cured silicone rubber having excellent resistance against oils, e.g., automobile engine oil, and little responsible for foaming of the oil contaminated with the silicone rubber, can be prepared by first blending a silanol-terminated dimethyl polysiloxane, an iminoxy-substituted organosilane compound, e.g., vinyl tributanoxime silane, an organotin compound as a catalyst and an inorganic filler. e.g, zinc oxide, to give a uniform mixture and further admixing the uniform mixture with a trimethylsilyl-terminated dimethyl polysiloxane, an alkenyloxy-substituted organosilane compound, e.g., vinyl triisopropenyloxy silane, and a methyl polysiloxane having a network structure of the molecules as consisting of the monofunctional units of the formula (CH.sub.3).sub.3 SiO.sub.0.5 and tetrafunctional units of the formula SiO.sub.2 each in a specified amount.

Abstract: Aqueous dispersions of organopolysiloxanes containing the following components:(A) Organopolysiloxane having groups which can undergo condensation;(B) condensation catalyst;(C) organopolysiloxane resin; and(D) diorganosilanolate and/or condensation products thereof formed by splitting off water.

Abstract: A hard coating composition comprising an organic silicon compound and inorganic submicron particles such as silica sol and antimony oxide sol is improved in curing properties and shelf stability by blending aluminum perchlorate as the curing catalyst.

Abstract: A novel primer composition containing a partial hydrolyzate of an aminoalkyl-substituted trialkoxysilane, a carboxylic acid salt of tin and a solvent is applied to a moisture-cured silicone substrate and dried to improve the adhesion of a subsequently applied coating. The composition and method are of particular value for painting a moisture-cured silicone substrate disposed on a support, such as a building sealant used on a window assembly or an encapsulant used on an electrical device.

Abstract: An improved silica-containing curable coating composition is described herein. The composition has an alkaline pH and contains a dialkyldialkoxysilane/alkyltrialkoxysilane mixture and a dispersion of ammonium-stabilized colloidal silica having an average particle size no greater than about 5-10 millimicrons. Methods for preparing such compositions are also disclosed, as are thermoplastic articles which include the cured protective coatings.

Abstract: This invention relates to materials produced by diluting in a solvent a platinum or rhodium catalyzed preceramic mixture of a hydrogen silsesquioxane resin. The preceramic mixture solvent solution is applied to a substrate and ceramified by heating. One or more ceramic coatings containing silicon carbon, silicon nitrogen, or silicon carbon nitrogen can be applied over the ceramified SiO.sub.2 coating. A CVD or PECVD top coating can be applied for further protection. The invention is particularly useful for coating electronic devices.

Abstract: Organopolysiloxane compositions curable into elastomeric state, whether in single- or two-component form, comprise an .alpha.,.omega.-dihydroxypolydiorganopolysiloxane oil, a crosslinking agent therefor, optionally, inorganic fillers and an adhesion promoter, and a catalytically effective amount of a pentacoordinated tin monochelate produced by reacting a tin oxide with a .beta.-dicarbonyl compound and a carboxylic acid.

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: Colloidal suspensions of organopolysiloxanes are prepared by mixing an organosilicon compound selected from the group consisting of mixtures of alkoxysilanes and/or partial hydrolysates thereof and an organo(poly)siloxane which is optionally free of alkoxy groups and contains a maximum of 8 siloxane units, which is mixed with at least one alkoxysilane and/or a partial hydrolysate thereof, with water in the presence of an emulsifier, at a maximum rate of 5 moles of organosilicon compound per hour per liter of water, in which the organosilicon compound and the water is fed continuously, but separately from one another, into a reactor, in which at least one of the two substances contains an emulsifier, while the alkanol is being continuously removed by distillation from the aqueous suspension continuously emerging from the reactor. The aqueous suspension from which the alkanol has been removed by distillation is, if desired, recycled back into the reactor.

Abstract: Single-component diorganopolysiloxane compositions which are storage-stable in the absence of atmospheric moisture and which crosslink into silicone elastomeric state in the presence of moisture, are comprised of an alkoxy-terminated diorganopolysiloxane, a functionalization catalyst containing a primary or secondary amine group, a tin condensation catalyst, a filler material, and an effective stabilizing amount of an isocyanurate of the formula: ##STR1## wherein W is --CH.sub.2).sub.n N.dbd.C.dbd.O and n ranges from 1 to 12.

Abstract: Ethoxylated siloxane surfactants, and mixtures of such surfactants with curable silicone prepolymers. The mixtures are hydrophilic after cure, have semipermanent hydrophilicity, and are especially useful as dental impressions.

Abstract: Cohesive bonding between silicone rubber compositions and plastics is achieved using primer compositions comprising a solution of at least one member of a specified class of organotitanate esters in an organic liquid. Cohesive bonding of silicone rubber compositions to both plastic and metals is achieved by including at least one member from either of two specified classes of organosilicon compounds in the primer composition together with the organotitanate ester.

Abstract: Disclosed are essentially zinc-free, organic coating compositions based on silicon-containing polyols comprising reaction products of hydrophobic polyols, organosilicon-containing materials, and higher monohydric alcohols, R-OH. The organosilicon-containing material comprises an organosilicon-containing substance free of certain functional groups attached directly to carbon and essentially free of alkali metal ions. The organosilicon-containing substance has atoms bonded directly to Si all of which are selected from O, N, and/or Cl. The organosilicon-containing substance also has moieties directly bonded to Si which are displaceable by reaction with water and/or alcohol. The reaction product is not capable of being gelled when subjected to a specific gel test, has a content of hydroxyl groups from the hydrophobic polyol ranging from 0.4 to 10 milliequivalents per gram of reaction product, has a content of groups, --OR, from the higher monofunctional alcohol ranging from 0.

Abstract: The present invention relates to a alkoxy-functional one-component RTV composition. In particular, there is disclosed processes for producing an alkoxy-terminated diorganopolysiloxane by reacting a vinyl or silanol containing siloxane with an alkoxy-functional hydride containing silane in the presnce of a platinum catalyst.

Abstract: Novel room temperature vulcanizable polydiorganosiloxane compositions comprising an .alpha.,.omega.-dihydroxypolydiorganosiloxane and a poly (alkoxysilylalkyl)amine. These compositions are neutral cure, exhibit excellent shelf life stability, possess a practically controllable cure rate and upon curing produce elastomers which have good adhesion to building materials and which possess good weatherability.

Abstract: A titanium chelate catalyst for a room temperature vulcanizable silicone rubber composition which does not form nodules upon storage where the catalyst has the formula, ##STR1## where s varies from 0.7 to 1.3 and t varies from 0.7 to 1.3. Preferably s varies from 0.8 to 1.2 and t varies from 0.8 to 1.2.

Abstract: Organophosphazene polymers having acyloxysilyl or alkoxysilyl substituents are curable at room temperature when exposed to atmosphere containing moisture.

Abstract: Vinylphenol derivatives of the formula I ##STR1## where A and R.sup.1 to R.sup.7 have the meanings stated in claim 1 and in the description, and their physiologically tolerated salts, drugs prepared from these, and their use for the treatment of various disorders of the skin, the mucous membranes and the internal organs, and of rheumatic disorders.

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: An improved silicone elastomeric sealant composition is produced by mixing alkoxy functional polydiorganosiloxane having alkoxysilethylene ends with a combination of trifunctional or tetrafunctional silane crosslinker and defunctional silane chain extender. The sealant composition is stable upon storage in the absence of moisture, but cures to an elastomer upon exposure to moisture. The cured composition can be adjusted for the desired elongation by varying the ratio of crosslinker to chain extender, but there must be at least 50 mol percent of crosslinker in the composition to ensure that the composition cures to a non-tacky surface.

Abstract: According to the present invention, an aqueous silicone emulsion composition is produced as follows. A base emulsion is prepared from prescribed quantities of an essentially straight-chain organopolysiloxane with at least 2 silicon-bonded hydroxyl groups in each molecule, colloidal silica or alkali metal silicate, a curing catalyst, an emulsifier and water. After the pH is adjusted to 9 to 12 and ripened until an elastomer material is formed by the removal of water at room temperature, prescribed quantities of an epoxy-functional silane coupling agent or its partial hydrolysis product or its partial hydrolysis condensation product, a filler and a dispersant are added. The produced aqueous silicone emulsion composition bonds tightly to porous substrates in contact with it during curing and is therefore extremely useful as a coating or sealing material for various porous substrates.

Abstract: Novel room temperature vulcanizable polydiorganosiloxane compositions comprising an .alpha.,.omega.-dihydroxypolydiorganosiloxane and a poly-(alkoxysilylalkyl)amine. These compositions are neutral cure, exhibit excellent shelf life stability, possess a practically controllable cure rate and upon curing produce elastomers which have good adhesion to building materials and which possess good weatherability.

Abstract: Compositions of hydroxyl endblocked polydiorganosiloxanes and tetrafunctional ethoxy-ketoximo silane mixtures containing tetraketoximosilane, monoethoxytriketoximosilane, diethoxydiketoximosilane, and triethoxymonoketoximosilane provide one package room temperature compositions. Exposing these compositions to moisture results in a rapid cure without the use of a curing catalyst.

Abstract: This invention describes a method of producing a silicone elastomer from an emulsion. When the ingredients are mixed together, the resulting latex can be used immediately. Removing the water from the latex results in a silicone elastomer. The method combines (A) an anionically stabilized, hydroxyl endblocked polydiorganosiloxane, present as an emulsion of dispersed particles in water, the emulsion having a pH of greater than 9, (B) dialkyltindicarboxylate, (C) alkylorthosilicate, (D) colloidal silica, and optionally (E) water, admixing (A) and (B) only in the presence of (C) to produce a dispersion of the ingredients in water. The ingredients can be distributed into a two-part system for storage. One embodiment includes fibers, lauryl alcohol, or a mixture of both in the emulsion; then forms an open-cell, elastomeric foam by forming a froth from the emulsion and removing the water from the froth.

Abstract: This invention describes a method of producing a silicone elastomer from an emulsion. When the ingredients are mixed together, the resulting latex can be used immediately. Removing the water from the latex results in a silicone elastomer. The method combines (A) an anionically stabilized, hydroxyl endblocked polydiorganosiloxane, present as an emulsion of dispersed particles in water, the emulsion having a pH of greater than 9, (B) dialkyltindicarboxylate, (C) alkylorthosilicate, (D) colloidal silica, and optionally (E) water, admixing (A) and (B) only in the presence of (C) to produce a dispersion of the ingredients in water. The ingredients can be distributed into a two-part system for storage. One embodiment includes fibers, lauryl alcohol, or a mixture of both in the emulsion; then forms an open-cell, elastomeric foam by forming a froth from the emulsion and removing the water from the froth.

Abstract: This invention describes a method of producing a silicone elastomer from an emulsion. When the ingredients are mixed together, the resulting latex can be used immediately. Removing the water from the latex results in a silicone elastomer. The method combines (A) an anionically stabilized, hydroxyl endblocked polydiorganosiloxane, present as an emulsion of dispersed particles in water, the emulsion having a pH of greater than 9, (B) dialkyltindicarboxylate, (C) alkylorthosilicate, (D) colloidal silica, and optionally (E) water, admixing (A) and (B) only in the presence of (C) to produce a dispersion of the ingredients in water. The ingredients can be distributed into a two-part system for storage. One embodiment includes fibers, lauryl alcohol, or a mixture of both in the emulsion; then forms an open-cell, elastomeric foam by forming a froth from the emulsion and removing the water from the froth.

Abstract: The room temperature-curable organopolysiloxane composition of the invention is characteristic in the remarkably increased adhesive bonding strength of the rubber of the composition to the surface of a substrate of metals, plastics and others on which the composition has been cured. The composition is also advantageous in the improved thixotropy despite the admixture of an adhesion improver mentioned below. Thus, the composition comprises, in addition to conventional components in a deacidification type room temperature curable organopolysiloxane composition, a specific organic silicon compound represented by the general formula(R.sup.3 O).sub.b (MeCOO).sub.3-b Si--O--R.sup.4 --O--Si(OCOMe).sub.3-b (OR.sup.3).sub.b,in which R.sup.3 is a monovalent hydrocarbon group, R.sup.4 is a divalent hydrocarbon group or a polyoxyalkylene group of the formula --C.sub.x H.sub.2x --O).sub.n C.sub.x H.sub.2x --, x being 2 to 4 and n being a positive integer, and b is 1 or 2.

Abstract: Macromolecular material of ionic conduction constituted by a salt in solution in a polyether. The polyether is polycondensed and/or cross-linked and presents at least two chains connected to each other by a bridge that comprises a silicon, cadmium, boron or titanium atom connected to one of the chains by an oxygen atom.Application to producing electrodes and electrolytes for electrochemical accumulators.

Abstract: This invention relates to a medical sealant comprising polyorganosiloxane gel for sealing a junction part between living skin and a medical instrument penetrating through the skin, said polyorganosiloxane gel having a partially cross-linked three dimentional structure expressed by the basis general formula ofR.sub.n SiO.sub.(4-n)/2(wherein R represents hydrogen or monovalent hydrocarbonyl group and n represents an integer of 1 to 3), characterized in that said gel self-supports its figure at room temperature and has a hardness expressed by a loading weight of 1 g to 250 g by which a disc of a diameter of 10 mm sinks to 1.0 mm on the gel.

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: The organopolysiloxane in the inventive latex is modified with phosphonate ester-containing groups such as those expressed by the formula --Si--CH.sub.2 CH.sub.2 --PO(OEt).sub.2 (Et: ethyl group) and --Si--CH.sub.2 CH.sub.2 CH.sub.2 --PO(ODd).sub.2 (Dd: dodecyl group) and exhibits excellent performance in the applications as a fabric treatment agent and the like. The inventive organopolysiloxane latex can be prepared by the polymerizing reaction of an organosilicon compound or, preferably, an organopolysiloxane and a phosphonate ester-modified alkoxysilane emulsified together in an aqueous medium containing a surface active agent of the class of the organic sulfonic acid type or a sulfate ester type ones which serves both as an emulsifier and as an acid catalyst.

Abstract: The present invention relates to the use of paraffin waxes or microwaxes in silicone pastes, in particular in kneadable compositions for the production of accurate impressions of teeth. The silicone pastes are preferably cold-vulcanizing two-component silicone rubber systems which are known per se and in which two pastes are mixed and then crosslink after about 2-5 minutes at room temperature.

Abstract: A composition for coating, which comprises:(1) 100 parts by weight of film forming components comprising:(A) 10 to 90% by weight of an organosilane triol of the following formula and/or its partial condensate:R.sup.1 Si(OH).sub.3wherein R.sup.1 represents a monovalent group selected from the group consisting of alkyl groups having 1 to 3 carbon atoms and aryl groups, and(B) 90 to 10% by weight of colloidal silica; and(2) 5 to 40 parts by weight of a copolymer of:(C) a compound represented by the formula: ##STR1## wherein Q represents >C.dbd.O or the following formula: ##STR2## wherein each X may be either the same or different and each represents hydrogen atom or hydroxyl group, of which at least one is hydroxyl group, and R.sup.2 represents an alkyl group having 1 to 18 carbon atoms, and(D) an epoxy group-containing trialkoxysilane.

Abstract: A cured product which resists soiling under outdoor exposure obtained from a mixture of a silanol containing polyorganosiloxane having at least one silicon-bonded oxyalkylene radical of the formula --R.sup.1 O(R.sup.2 O).sub.n R.sup.3 and a curing agent.

Abstract: A method for producing solventless liquid organopolysiloxanes is disclosed. The method involves hydrolyzing an organo silicon composition comprising at least one compound having the general formulaY.sub.(4-n) Si(OR).sub.nwhere Y is phenyl or a primary or secondary alkyl group having from one to four carbon atoms, R is an alkyl group having from one to three carbon atoms, and n is an integer from one to four, and wherein the ratio of OR groups to silicon atoms in the composition is from 2.3:1 to 3.1:1. The products of hydrolysis are then heated to cause substantial siloxane formation by condensation and to distill water and alcohol by-products. Heating is continued until the water content of the resulting siloxane composition is less than 1 percent. The purity of the organo silicon composition, the amount of water used for hydrolysis, the amount of acid present during hydrolysis, and the heating of the organopolysiloxane are so controlled that the solventless organopolysiloxane has a viscosity at 25.degree. C.

Abstract: A one-component alkoxy-functional RTV silicone rubber composition which is made shelf-stable by the incorporation of scavengers in the composition to absorb hydroxy groups. The present composition is made low modulus by the incorporation of various additives in the composition such as a trifunctional fluid and a linear diorganopolysiloxane fluid. There is also disclosed the use of sag control additives in the uncured composition to impart to it thixotropic properties.

Abstract: The present invention provides a room temperature curable polyorganosiloxane composition comprising:(A) 100 parts by weight in total of:(1) a polydiorganosiloxane of the general formula: ##STR1## (2) a silane of the general formula:R.sub.b.sup.3 Si(OR.sup.4).sub.4-b(B) 0.01 to 10 parts by weight of a curing catalyst;(C) 0.5 to 10 parts by weight of a nitrogen-containing silicon compound in which the nitrogen atom is bonded with a silicon atom through one or more carbon atoms and said nitrogen atom is further bonded directly with said silicon atom or another silicon atom; and(D) 0.05 to 50 parts by weight of a polyoxyalkylene chain-containing compound.

Abstract: Polyorganosiloxane foams exhibiting a desirable combination of low density, an average cell size between 0.2 and 4 mm and a cell concentration of at least 4 per linear centimeter are obtained by dispensing and curing moisture curable organosiloxane compositions containing a dispersed liquid or gaseous blowing agent and, as a foam stabilizer, a resinous organosiloxane copolymer comprising trimethylsiloxy units, SiO.sub.4/2 units and fluorine-containing organosiloxane units. The polymer portion of the organosiloxane compositions can be a polydimethylsiloxane or a graft copolymer comprising at least 20 mole percent of dimethylsiloxane units in combination with organic units.

Abstract: Room temperature vulcanizable organopolysiloxane compositions are provided based on the use of a silanol or alkoxy terminated organopolysiloxane and an effective amount of a diorganotinbis(chelate) catalyst.

Abstract: Disclosed is a liquid composition comprising a homogeneous reaction product of a hydrophobic polyol and an organosilicon-containing material. The organosilicon-containing material comprises an organosilicon-containing substance free of functional groups attached to carbon and essentially free of alkali metal ions, having atoms bonded directly to silicon, all of which atoms are selected from O, N, and/or Cl. The organosilicon-containing substance additionally has moieties directly bonded to silicon which are displaceable by reaction with water and/or alcohol. At least a part of the organosilicon-containing substance is hydrolyzed to a compound or a mixture of compounds containing a residual amount of the moieties directly bonded to silicon which are displaceable.

Abstract: The invention provides a novel organopolysiloxane-containing aqueous emulsion composition which, upon removal of water by drying at room temperature, can give a cured rubbery elastomer having excellent mechanical properties and exhibiting strong adhesion to the substrate on which it has been cured. The inventive composition is prepared by blending (A) an aqueous emulsion of an organopolysiloxane having silicon-bonded hydroxy groups and emulsified in water by use of an anionic surface active agent, (B) a mixture of a reaction product of a carboxylic acid anhydride with an amino-functional organosilane and a colloidal silica in the form of an aqueous suspension and (C) a curing catalyst in limited proportions.

Abstract: Stable, substantially acid free, one package organopolysiloxane compositions are provided which have a base polymer, a condensation catalyst, a silane scavenger for hydroxy functional groups having cycloaliphatic enoxy functionality, and a curing accelerator, said compositions being curable upon exposure to atmospheric moisture to translucent and colorless tack-free elastomers.

Abstract: There is provided a one package RTV composition which is convertible to a tack-free elastomer comprising:(A) a polydiorganosiloxane base polymer,(B) an effective amount of a condensation catalyst, and(C) a stabilizing amount of organic scavenger for hydroxy groups which has the formula:R--N.dbd.C.dbd.O).sub.xwhere R is a linear or cyclic aliphatic compound or an aromatic compound, and x equals at least 1.

Abstract: A composition for making building materials water-repellent, before or after they are shaped, the composition containing organoalkoxysiloxanes of the formula ##STR1## in which R.sup.1 is an alkyl or aryl radical, R.sup.2 is an alkyl radical with 1 to 4 carbon atoms, a=0.8 to 1.5, and b is not greater than 2. The composition contains(a) 1 to 20% by weight of a mixture of organoalkoxypolysiloxanes of the aforementioned formula, 25 to 75% weight of organoalkoxysiloxanes having a b-value of 0.1 to 0.5 (siloxanes A) and 75 to 25% by weight of the organopolysiloxanes having a b-value 0.8 to 2.0 (siloxanes B), and in which the sum of a and b is not greater than 3,(b) 80 to 90% by weight of a water immiscible solvent and, if necessary,(c) known condensation catalysts.The organoalkoxysiloxane mixture has a surprisingly increased stability on alkaline walling. At the same time, a high depth of penetration and good surface effectiveness are observed.