Abstract: Curable perfluoropolyether rubber compositions are provided comprising (A) a linear perfluoropolyether compound containing at least two alkenyl groups and having a perfluoropolyether structure containing recurring units —CaF2aO— in its backbone, (B) an organosilicon compound containing at least two SiH groups, (C) an inorganic powder capable of chemical and/or physical adsorption of acidic gases and/or sulfur-containing gases, and (D) a hydrosilylation catalyst. The compositions cure into rubber or gel products having minimal permeability to acidic gases and sulfur-containing gases.

Abstract: A sealant used for the protection of an electric or electronic part is removed by contacting the sealant with tetramethylammonium hydroxide, tetrabutylammonium fluoride or the like for thereby dissolving the sealant. The method is capable of removing only the protective sealant from the electric or electronic part without causing damage to other components of the part.

Abstract: A composition comprising 100 parts by mass of (A) a linear fluoropolyether having at least two alkenyl groups, (B) a fluorine-containing organohydrogensiloxane having at least two SiH bonds in such an amount that an amount of the SiH bonds ranges from 0.5 to 3.0 moles per mole of the alkenyl group of the Component (A), (C) a platinum group metal compound in an amount of from 0.1 to 500 ppm calculated as the platinum group metal atom, and 1 to 50 parts by mass of (D) fumed silica having 350×1018/g or more of silanol groups on its surface. A cured product of the composition shows little migration.

Abstract: A curable fluoropolyether composition comprises (A) a fluoropolyether compound, (B) a perfluoropolyether, (C) an organohydrogenpolysiloxane, (D) spherical silica powder, (E) a fluorinated trialkoxysilane, and (F) a platinum catalyst. The composition can be heavily loaded with the silica (D). By virtue of using components (A) and (B) both having a perfluoroether structure in the backbone as the base polymer, the curable fluoropolyether composition cures through heating at a low temperature for a short time into a product having good heat resistance, freeze resistance, oil resistance, solvent resistance, chemical resistance, moisture resistance, and electrical insulation.

Abstract: Perfluoropolyether compositions are provided comprising (A) a linear perfluoropolyether compound containing at least two alkenyl groups, having a perfluoropolyether structure comprising recurring units —CaF2aO— in its backbone, and having a Mw of 10,000-100,000; (B) an organosilicon compound containing at least two silicon atom-bonded hydrogen atoms; (C) a reinforcing filler; (D) a hydrosilylation catalyst; and (E) a polyfluoromonoalkenyl compound containing one alkenyl group and having a perfluoropolyether structure in its backbone. The compositions cure into rubber or gel products having improved acid resistance.

Abstract: A curable composition comprising: (A) a branched polyfluorodialkenyl compound represented by a general formula (1): CH2?CH—(X)a-Rf1-(X?)a—CH?CH2??(1) wherein, X and X? are bivalent groups such as —CH2— and —CH2O—, a represents, independently, either 0 or 1, and Rf1 is a specific bivalent fluorine-containing group, (B) a branched polyfluoromonoalkenyl compound represented by a general formula (2): Rf2-(X?)a—CH?CH2??(2) wherein, X? and a are as defined above, and Rf2 is a specific fluorine-containing group, (C) an organohydrogensiloxane compound with at least two hydrogen atoms bonded to silicon atoms, and (D) a platinum group metal catalyst; as well as a low bleeding gel type cured product obtained by curing such a composition, and an electrical or electronic component sealed or encapsulated using such a cured product. The gel type cured product displays very little bleeding of free oil constituents from the gel as a result of stress such as pressure fluctuation or heat history.

Abstract: An adhesive composition comprising the following components: (A) a linear polyfluoro compound having at least two SiH bonds per molecule and a perfluoropolyether residue in a main chain of the linear polyfluoro compound (A); (B) an organohydrogensiloxane having a fluorinated group and at least two hydrogen atoms each bonded to a silicon atom per molecule; (C) a compound of a platinum group metal; (D) hydrophobic silica powder; (E) an alkoxysilane represented by the following formula (1) (RO)3—Si—T??(1) wherein R is a monovalent hydrocarbon group, T is a group represented by the formula, —OR1 or —CHR2—COOR3, wherein R1 is a monovalent hydrocarbon group, which may be the same with or different from R, R2 is a hydrogen atom or a methyl group and R3 is a monovalent hydrocarbon group; and (F) an organosiloxane having at least one SiH bond and at least one group selected from the group consisting of an epoxy group and a trialkoxysilyl group.

Abstract: A curable composition comprising an alkenyl-containing fluoropolymer comprising —(CF(CF3)—CF2—O)— units, an alkenyl-free, non-functional fluoropolymer comprising —[(CF2)kO]— units wherein k is 1 to 6, an organohydrogensiloxane and a catalyst, in the cured state, remains flexible even at low temperatures, minimizes the bleeding of free oil ingredients from the gel under stresses or thermal cycling, and has chemical resistance.

Abstract: A semiconductor package comprises a semiconductor chip, leads, and bonding wires wherein at least portions of the chip, bonding wires and leads are covered and protected with an electrically insulating fluorochemical material which is a cured product of a curable composition comprising (A) a polyfluorodialkenyl compound comprising —(CF(CF3)—CF2—O)— units and having alkenyl groups at both ends of its molecular chain, (B) an organohydrogenpolysiloxane having at least two Si—H groups, and (C) a platinum group metal catalyst.

Abstract: A curable composition comprising (A) a polyfluorodialkenyl compound having at least two alkenyl radicals, (B) a fluorinated organohydrogensiloxane having at least two Si—H radicals, (C) a platinum group compound, (D) a hydrophobic silica powder, and (E) an organosiloxane having a Si—H radical and a trialkyl or trialkoxy-containing organic radical attached to a silicon atom cures into a product having improved solvent resistance, chemical resistance, heat resistance, low-temperature properties, low moisture permeability and electric properties and exhibiting good adhesion to a variety of substrates including metals and plastics by brief heating at relatively low temperatures.

Abstract: In a semiconductor pressure sensor device comprising a housing (1) having a cavity (3), a semiconductor sensor chip (2) mounted within the cavity, leads (4) for conveying pressure detection signals, and bonding wires (6) electrically connecting the sensor chip and the leads, a sensitive portion (2a) of sensor chip (2), leads (4) and bonding wires (6) are covered with an electrically insulating fluorochemical gel material which has a penetration of 30-60 according to JIS K2220, a Tg of up to ?45° C., and a degree of saturation swelling in gasoline at 23° C. of up to 7% by weight. The sensor device is improved in operation reliability and durability life.

Abstract: An adhesive composition contains specific amounts of a linear polyfluoro compound having at least two alkenyl groups and a main chain with a perfluoropolyether structure, a fluorine-bearing organohydrogensiloxane having at least two silicon-bonded hydrogens, a platinum group compound, a hydrophobic silica powder, an isocyanurate bearing at least lo one epoxy group and/or trialkoxysilyl group bonded indirectly to a nitrogen atom, and an organosiloxane bearing a silicon-bonded hydrogen and at least one epoxy group and/or trialkoxysilyl group indirectly bonded to a silicon atom. The composition, when heated for a short period of time, has an excellent adhesion to a broad range of substrates and provides a coat of uniform thickness.

Abstract: In fluorinated curable compositions comprising alkenyl group-bearing perfluoropolyethers as the base polymer to ensure chemical resistance and solvent resistance together with an organohydrogensiloxane and a platinum group metal catalyst, a hydrophobized silica fine powder is used in combination therewith to render the compositions thixotropic.

Abstract: A sealant used for the protection of an electric or electronic part is removed by contacting the sealant with tetramethylammonium hydroxide, tetrabutylammonium fluoride or the like for thereby dissolving the sealant. The method is capable of removing only the protective sealant from the electric or electronic part without causing damage to other components of the part.

Abstract: A curable composition comprising (A) a polyfluorodialkenyl compound having at least two alkenyl radicals, (B) a fluorinated organohydrogensiloxane having at least two Si—H radicals, (C) a platinum group compound, (D) a hydrophobic silica powder, and (E) an organosiloxane having a Si—H radical and a trialkyl or trialkoxy-containing organic radical attached to a silicon atom cures into a product having improved solvent resistance, chemical resistance, heat resistance, low-temperature properties, low moisture permeability and electric properties and exhibiting good adhesion to a variety of substrates including metals and plastics by brief heating at relatively low temperatures.

Abstract: In a semiconductor pressure sensor device comprising a housing (1) having a cavity (3), a semiconductor sensor chip (2) mounted within the cavity, leads (4) for conveying pressure detection signals, and bonding wires (6) electrically connecting the sensor chip and the leads, a sensitive portion (2a) of sensor chip (2), leads (4) and bonding wires (6) are covered with an electrically insulating fluorochemical gel material which has a penetration of 30-60 according to JIS K2220, a Tg of up to −45° C., and a degree of saturation swelling in gasoline at 23° C. of up to 7% by weight. The sensor device is improved in operation reliability and durability life.

Abstract: A curable composition comprising an alkenyl-containing fluoropolymer comprising —(CF(CF3)—CF2—O)— units, an alkenyl-free, non-functional fluoropolymer comprising —[(CF2)kO]— units wherein k is 1 to 6, an organohydrogensiloxane and a catalyst, in the cured state, remains flexible even at low temperatures, minimizes the bleeding of free oil ingredients from the gel under stresses or thermal cycling, and has chemical resistance.

Abstract: A fluorinated curable composition in which a fluorinated organohydrogensiloxane as the curing agent is well compatible with a linear polyfluoro compound as the base yields a cured gel having good adhesion to substrates and improved chemical and solvent resistance.

Abstract: A curable composition comprising (A) a fluorinated amide compound having alkenyl radicals, (B) a fluorinated organohydrogensiloxane having SiH radicals, (C) a platinum group compound, (D) a silica powder, (E) an organosilane or organosiloxane having a monovalent perfluorooxyalkyl or perfluoroalkyl, divalent perfluorooxyalkylene or perfluoroalkylene radical and a hydroxy and/or alkoxy radical, and (F) an organosilane or organosiloxane having an alkenyl radical, a monovalent perfluorooxyalkyl or perfluoroalkyl, divalent perfluorooxyalkylene or perfluoroalkylene radical, and a hydroxy and/or alkoxy radical cures into a fluorinated elastomer that has good solvent resistance, chemical resistance, heat resistance, low-temperature properties, mold release, water and oil repellency and weather resistance as well as significantly improved mechanical strength and compression set.

Abstract: A curable composition comprising: