Dow Corning Corporation

Beth I Gutek

Bernard Van Wert

Antony P Wright

Loren D Lower

Herschel Henry Reese

Vicky Sue Cobb

Sherwood Spells

Gary E Le Grow

Gust J Kookootsedes

Alan Zombeck

Gale H Pretzer

A composition which is a silicone polyether containing arylalkyl groups, most preferably an arylalkyl group such as the 2-phenylpropyl group, i.e., --CH.sub.2 CH(C.sub.6 H.sub.5)CH.sub.3. The compositions demonstrate improvements in emulsification over silicone polyethers without such arylalkyl groups. The compositions have a formula generally corresponding to

Silicone polyethers with arylalkyl groups

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 &lt;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 &gt;700 dynes/cm.sup.2 and a shear-thinned viscosity of no more than 1,000 Pa.s at a shear stress of 50,000 dynes/cm.sup.2. RTV silicone sealant compositions can be obtained in 10 to 15 minutes from the start of making the surface modified silica filler to the complete sealant composition.

Method of making a foundation polydiorganosiloxane-silica mixture, the

New alkylpolyether siloxanes are prepared by reacting an unsaturated ether with alkylhydrido siloxanes such as (i) comonomers RSi(OSiMe.sub.2 H).sub.3, (ii) oligomers (HMe.sub.2 SiO).sub.2 --Si(R)--O--Si(R)--(OSiMe.sub.2 H).sub.2, and (iii) higher molecular weight siloxane species RSi[(OSiMe.sub.2).sub.x OSiMe.sub.2 H].sub.3 and [HMe.sub.2 SiO(Me.sub.2 SiO).sub.x ].sub.2 Si(R)O(R)Si[(OSiMe.sub.2).sub.x OSiMe.sub.2 H].sub.2. R is a C.sub.2 to C.sub.18 straight-chain or branched-chain alkyl substituent.

Alkylpolyether siloxanes

A conformal coating composition is made from a mixture of acrylamide functional polydimethylsiloxane, a methacrylate functional/dialkoxy polydiorganosiloxane, reactive diluent including isobornyl acrylate, cyclohexyl acrylate, and 2- ethylhexyl acrylate; a photoinitiator combination of 2-hydroxy- 2-methylphenylpropanone and 2-methyl-1-[4-(methylthio)phenyl]-2- morpholenopropanone, an amine including dimethylethanolamine and diisopropylethylamine, and an organic titantate. The composition has a viscosity of from 0.07 to 0.2 Pa.s at 25.degree. C. and cures by exposure to ultraviolet radiation and to atmospheric moisture, i.e. a dual curing composition. This composition cures too fast by exposure to ultraviolet radiation in the presence of nitrogen resulting in a distorted surface and therefore for coating printed circuit boards it is recommended that it be cured in air so that the rate of cure is reduced and no surface distortions are formed.

UV curable conformal coating with moisture shadow cure

Organosilicon compounds containing at least one acylamino-substituted hydrocarbon radical are prepared by reacting an organosilicon compound containing at least one amino-substituted hydrocarbon radical with an acyl halide in the presence of a large particle size solid base such as a basic ion exchange resin. A solvent is required only when it is necessary to reduce the viscosity of the reactants.

Process for synthesis of acylamino organosilicon compounds

The curable polyorganosiloxane compositions of this invention comprise at least one vinyl-terminated liquid polydiorganosiloxane, a resinous organosiloxane reinforcing agent that includes diorganovinylsiloxy, triorganosiloxy and SiO.sub.2 units, an organosiloxane curing agent containing an average of at least three silicon-bonded hydrogen atoms per molecule, a diorganohydrogensiloxy terminated polydiorganosiloxane as a chain extender in an amount sufficient to provide from 10 to 85 percent of the silicon-bonded hydrogen atoms in the composition, and a platinum-containing hydrosilation catalyst. The compositions contain at least 1.5 vinyl radicals for each silicon-bonded hydrogen atom present in the composition. The cured elastomer is compressible, resilient and exhibits a hardness value of up to 100 on the Shore 00 durometer scale.

Liquid curable polyorganosiloxane compositions

A conformal coating composition is made from a mixture of acrylamide functional polydimethylsiloxane, a methacrylate functional/dialkoxy polydiorganosiloxane, reactive diluent including isobornyl acrylate, cyclohexyl acrylate, and 2-ethylhexyl acrylate; a photoinitiator combination of 2-hydroxy-2-methylphenylpropanone and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholenopropanone, an amine including dimethylethanolamine and diisopropylethylamine, and an organic titanate. The composition has a viscosity of from 0.07 to 0.2 Pa.s at 25.degree. C. and cures by exposure to ultraviolet radiation and to atmospheric moisture, i.e. a dual curing composition. This composition cures too fast by exposure to ultraviolet radiation in the presence of nitrogen resulting in a distorted surface and therefore for coating printed circuit boards it is recommended that it be cured in air so that the rate of cure is reduced and no surface distortions are formed.

Touch position sensitive optical waveguides comprise a layer of optically transparent polyorganosiloxane elastomer exhibiting a hardness of up to 100 on the Shore 00 scale. The elastomer layer is the product of a hydrosilation reaction and at least one surface of the layer bears a dirt- and puncture-resistant coating formed from a polyurethane, a polyorganosiloxane or an organosiloxane/urethane copolymer. The compressability, compressive strength and resiliency of the waveguide are within specified limits.

Touch position sensitive optical waveguides

The method of this invention produces a silicone coated glass fabric which is translucent or transparent as desired and which has a smooth dry surface. The coated glass fabric is useful in producing air-supported and tension-supported roofs for structures such as greenhouses. A glass fabric is first coated with a polydiorganosiloxane, in which the organo radicals are methyl and phenyl radicals in a ratio of from 0.25 to 3.7, in an amount sufficient to impregnate the fibers in the yarns of the fabric, but leaving the interstices of the fabric open. This first layer is then followed by coating with a polydimethylsiloxane elastomer to give a continuous layer, then coating with an elastoplastic organopolysiloxane resin to give a smooth, dry surface on the glass fabric reinforced sheet.

Clear silicone coated fabric

The method of this invention produces a silicone resin-coated fabric comprising an elastoplastic organopolysiloxane resin coated silicone elastomer membrane reinforced with fabric. The elastoplastic organopolysiloxane resin and the silicone elastomer membrane form an interface which is an adhesive bond derived from a combination comprising (i) polydiorganosiloxane of the formula X(R.sub.2 SiO).sub.a SiR.sub.2 X, (ii) a hydroxyl radical containing, solid, benzene soluble resin copolymer consisting essentially of R.sub.3 SiO.sub.1/2 units and SiO.sub.4/2 units, and (iii) a condensation catalyst for (i) and (ii). The bond between the layers of the silicone resin-coated fabric is of such a quality that the silicone resin-coated fabric can be adhesively bonded to itself, or another surface, to produce useful structures such as air supported roofs or tension supported roofs.

Flexible silicone resin coated fabric

This invention provides liquid coating compositions comprising (a) a film-forming component comprising at least one organosiloxane block copolymer wherein the molar ratio of phenylsiloxane units to other units present in the block copolymer is greater than 0.35 to 1, and (b) a solvent comprising at least 45% by weight of a cyclic polydimethylsiloxane of the formula [(CH.sub.3).sub.2 SiO].sub.x where the average value of x is from 3 to 8 and where said organosiloxane block copolymer constitutes no more than 60% of the combined weight of the copolymer and solvent. Using the present compositions, relatively thin coatings of the block copolymer can be applied to cured polyorganosiloxane elastomers and a variety of synthetic organic polymers.

Liquid organosiloxane resin compositions

Translucent polyorganosiloxane resin compositions exhibiting acceptable levels of flame retardancy contain from 1 to 10%, based on resin weight, of an organic halogen source in combination with finely divided glass particles. Translucent substrates coated with these resin compositions can be used in the exterior portions of buildings intended to be heated at least in part by solar energy.

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Freeland, MI, United States of America

Beth I Gutek