Dow Corning Corporation

John G Price

Kenneth Christopher Fey

Terence J Swihart

Alan L Freiberg

Danielle M Fillmore

Solventless liquid silicone resin compositions are prepared by first reacting a mixture of (A) a polydimethylsiloxane and (B) a methyltrialkoxysilane in the presence of (C) an equilibrating amount of a perfluoroalkane sulfonic acid; hydrolyzing the reaction product formed with sufficient water to provide from about 0.48 to about 0.81 mole of residual alkoxy functionality per 100 parts by weight of said liquid silicone resin; and neutralizing the acid catalyst. Alternatively, the above components can be similtaneously reacted and then neutralized to form the resins of the present invention. The liquid silicone resins are storage stable, have low viscosities and can be cured to form heat-resistant protective coatings on substrates.

Liquid silicone resin compositions

A method of reducing the volatility and decreasing the evaporation loss of water repellent compositions containing a solution of an alkylalkoxysilane and a carrier prior to application of the composition to a porous substrate by acidifying the solution in order to cause rapid equilibriation of the alkylalkoxysilane and the carrier to a constant steady state condition, adding to the acidified hydrolyzed alkylalkoxsilane solution at least one metal salt catalyst to further increase the hydrolysis rate of the alkylalkoxysilane and to complete the hydrolysis and the condensation of the alkylalkoxysilane, adding at least one surface depositing agent to the acidified hydrolyzed alkylalkoxysilane solution in order to reduce evaporation of un-reacted alkylalkoxysilane, and maintaining the solution in a substantially anhydrous condition, so that the amount of hydrolyzed silane absorbed by the porous substrate and the percentage of water excluded from the porous substrate by the repellent composition are increased.

Low volatility water repellents

A water repellent composition for porous substrates formed by combining an alkylakoxysilane with a carrier selected from the group consisting of alcohols, mineral spirits, and glycol ethers, together with an effective amount of a surface depositing agent for producing on the surface of the porous substrate a water beading-water shedding surface coating, and a metal salt catalyst. The method of producing on a porous substrate a water beading-water shedding surface coating by applying to the porous substrate the foregoing composition is also disclosed.

Water beading-water shedding repellent composition

A siloxane treating composition comprises (1) a mixture and/or a reaction product of (A) a polydiorganosiloxane having at least one silicon-bonded --OX group, X being H, alkyl or alkoxyalkyl and at least one silicon-bonded aminoalkyl or polyaminoalkyl acid salt group, and (B) a silicon compound having more than 2 silicon-bonded groups which are reactive with --OX of (A), and (2) a water-soluble solvent for (A) which comprises one or both glycol ethers of the formula C.sub.4 H.sub.9 --O--(CH.sub.2 --CH.sub.2 --O).sub.n H where n is 1 or 2. These compositions have improved penetration ability and stability, especially when used as aqueous composition for rendering substrates, such as masonry, hydrophobic. Also claimed is a process for making such compositions and a process for applying them to substrates.

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South Glamorgan, United Kingdom

John G Price