摘要:
A moisture-curable silicone hot melt pressure-sensitive adhesive composition is disclosed, said composition comprising (i) a solid hydroxyl-functional organopolysiloxane resin comprising R₃SiO 1/2 siloxane units and SiO 4/2 siloxane units in a molar ratio of 0.5/1 to 1.2/1, respectively, wherein R is selected from hydrocarbon and halogenated hydrocarbon radicals and said hydroxyl content is 1.2 to 6 percent by weight; (ii) an alkoxy-functional diorganopolysiloxane polymer having a viscosity at 25°C. of 20 to 100,000 mPa·s (centipoise), the weight ratio of said resin to said polymer being in the range 40:60 to 80:20; (iii) a silane of the formula R' 4-y SiX y , in which R' is selected from hydrocarbon radicals and substituted hydrocarbon radicals having 1-6 carbon atoms, X is a hydrolyzable group and y is 2 to 4, the amount of said silane being sufficient to provide stability to said composition; and (iv) sufficient catalyst to accelerate the cure of said composition, said composition being an essentially solvent-free, non-slump solid at room temperature which cures to an essentially non-tacky elastomer upon exposure to moisture.
摘要:
A method for enhancing the dielectric properties of new or in-service electrical cable is disclosed, the method comprising supplying the interstitial void space of the cable's conductor with a fluid mixture comprising
(A) an antitreeing agent; and (B) a water-reactive compound,
wherein (B) has a diffusion coefficient of at least 1 x 10⁻⁷ cm²/second at 50°C. in the insulation of the cable and the mixture has an initial viscosity of ≦100 cP (mPa·s) at 25°C. The instant method provides a more symmetrical distribution of dielectric enhancing fluid in the insulation than prior art approaches and results in a significant reduction in cable treatment time.
摘要:
A composition comprising a major portion of a polyolefin and a minor portion of a siloxane having at least one silicon bonded unsaturated, substituted or unsubstituted, hydrocarbon radical substituent is disclosed. A method of stabilizing polymers against water and electrical treeing which comprises adding a siloxane as defined above is further disclosed.
摘要:
A composition is disclosed comprising a polymeric component and an additive selected from the group consisting of (a) R a Si (OX) 4-a , (b) a partial hydrolyzate of R a Si(OX) 4-a , (c) a partial cohydrolyzate of R a Si (OX) 4-a and R b 'Si (OY) 4-b , and (d) a partial hydrolyzate condensation product of a siloxane and R a Si (OX) 4-a wherein R, X R', and Y are substituted or unsubstituted hydrocarbon radicals and at last one substituent per additive is an unsaturated hydrocarbon radical; and a and b have values of 0 to 3. A method of stabilizing polymers against water and electrical treeing, which comprises adding the additive as defined above, is further disclosed.
摘要:
A composition comprising a polymeric component and a siloxane, having at least one silicon bonded group having the general formula -OX wherein X is an unsaturated hydrocarbon radical, is disclosed. A method of stabilizing polymers against water and electrical treeing, which comprises adding a siloxane having at least one silicon bonded group having the general formula -OX wherein X is an unsaturated hydrocarbon, is further disclosed.
摘要:
Disclosed are coating compositions which include hydrogen silsesquioxane resin dissolved in saturated alkyl hydrocarbons. The compositions are useful for forming coatings which are thick and/or have good coating quality.
摘要:
A moisture-curable silicone hot melt pressure-sensitive adhesive composition is disclosed, said composition comprising (i) a solid hydroxyl-functional organopolysiloxane resin comprising R₃SiO 1/2 siloxane units and SiO 4/2 siloxane units in a molar ratio of 0.5/1 to 1.2/1, respectively, wherein R is selected from hydrocarbon and halogenated hydrocarbon radicals and said hydroxyl content is 1.2 to 6 percent by weight; (ii) an alkoxy-functional diorganopolysiloxane polymer having a viscosity at 25°C. of 20 to 100,000 mPa·s (centipoise), the weight ratio of said resin to said polymer being in the range 40:60 to 80:20; (iii) a silane of the formula R' 4-y SiX y , in which R' is selected from hydrocarbon radicals and substituted hydrocarbon radicals having 1-6 carbon atoms, X is a hydrolyzable group and y is 2 to 4, the amount of said silane being sufficient to provide stability to said composition; and (iv) sufficient catalyst to accelerate the cure of said composition, said composition being an essentially solvent-free, non-slump solid at room temperature which cures to an essentially non-tacky elastomer upon exposure to moisture.
摘要:
There is disclosed the use of a quaternary ammonium salt of an alkoxysilane as a dispersant for magnetic pigment particles in the preparation of magnetic recording media. The dispersant of the present invention can bind to the pigment particles and may be substituted for conventional phosphate ester dispersants which are incapable of binding to the pigment and tend to migrate to the surface of such media, thereby adversely affecting recording media performance.
摘要:
An organosilane of the general formula where R denotes a hydrogen or alkyl radical, n is 2 to 5, Ph denotes an aryl radical, and R' denotes an alkyl radical, and the hydrolysis product, a disiloxane, of said organosilanes with water, where said compounds are useful as anti-treeing additives to polyolefin.
摘要:
There is provided a method of extending the serviceable life of a stranded conductor electrical distribution cable wherein the interstices of the conductor are filled with a curable silicone water block composition which is subsequently cured to a non-flowing state. The composition has a low viscosity and comprises (A) an Si-H endblocked polydiorganosiloxane fluid, (B) a polydiorganosiloxane fluid endblocked with an unsaturated organic radical, (C) a siloxane crosslinker, (D) a hydrosilation catalyst and (E) a polymerization inhibitor. Proper selection of catalyst and inhibitor concentrations imparts a controllable viscosity-time profile to the composition and allows cables of various sizes and lengths to be filled before the water block composition cures.