Abstract: A primer composition for a fluorinated elastomer or a fluorinated gel, said primer composition comprising: 100 parts by weight of (a) a linear perfluoro polyether compound having at least two alkenyl groups per molecule, a perfluoro polyether backbone having repeating units represented by the formula, —CaF2aO—, wherein a is an integer of from 1 to 6, and a weight average molecular weight of from 5,000 to 100,000, (b) an organosiloxane compound having one or more fluorine atom and at least two SiH bonds per molecule, in such an amount that a molar ratio of the SiH bond in the organosiloxane compound to the alkenyl group in Component (a) ranges from 0.8 to 5.

Abstract: A curable fluoropolyether rubber composition comprising (A) a straight-chain fluoropolyether compound having at least two alkenyl groups in a molecule and a perfluoropolyether structure in the backbone, (B) an organosilicon compound having at least two hydrosilyl groups in a molecule, (C) a compound containing at least one fluorine atom and at least one benzene ring in a molecule, free of a polar group, having a melting point of at least 50° C., in powder form, and (D) a hydrosilylation catalyst cures into a rubber product having solvent resistance, chemical resistance, improved mold release property and satisfactory compression set.

Abstract: A primer composition for a fluorinated elastomer or a fluorinated gel, said primer composition comprising: 100 parts by weight of (a) a linear perfluoro polyether compound having at least two alkenyl groups per molecule, a perfluoro polyether backbone having repeating units represented by the formula, —CaF2aO—, wherein a is an integer of from 1 to 6, and a weight average molecular weight of from 5,000 to 100,000, (b) an organosiloxane compound having one or more fluorine atom and at least two SiH bonds per molecule, in such an amount that a molar ratio of the SiH bond in the organosiloxane compound to the alkenyl group in Component (a) ranges from 0.8 to 5.

Abstract: A crosslinkable fluororubber composition comprising (A) a polymer of the formula: Z-(Rf-Q)n—Rf-Z wherein n is an integer of at least 1, Rf is a divalent perfluoroalkylene or perfluorooxyalkylene radical, Q is a divalent organic radical, and Z is a monovalent organic radical, having a viscosity of at least 1,000 Pa·s at 25° C., (B) a reinforcing filler, and (C) a peroxide crosslinking agent is effectively roll milled and experiences minimal changes of viscosity after milling. Molded parts can be produced on a mass scale.

Abstract: A primer composition comprises (a) a fluoroalkylene or fluoropolyether compound having at least one alkenyl radical and at least one hydrolyzable silyl radical, (b) an organic titanic acid ester, (c) an organic tin compound, and (d) a silane compound. The primer composition is fully adherent to various substrates of metals, glass, ceramics, cement, mortar, carbon, and plastics, and is particularly suited for use with a thermosetting elastomer composition based on a polymer having at least two alkenyl radicals and a perfluoropolyether structure in its backbone.

Abstract: A rubber composition is obtained by mixing (a) a perfluoropolyether-base fluororubber composition having Si—CH?CH2 as crosslinking sites with (b) a silicone rubber composition having the same crosslinking system as component (a). The resulting blend has the advantages of both the fluororubber and silicone rubber compositions.

Abstract: A primer composition comprises (a) a fluoroalkylene or fluoropolyether compound having at least one alkenyl radical and at least one hydrolyzable silyl radical, (b) an organic titanic acid ester, (c) an organic tin compound, and (d) a silane compound. The primer composition is fully adherent to various substrates of metals, glass, ceramics, cement, mortar, carbon, and plastics, and is particularly suited for use with a thermosetting elastomer composition based on a polymer having at least two alkenyl radicals and a perfluoropolyether structure in its backbone.

Abstract: A curable fluoropolyether rubber composition comprising (A) a straight-chain fluoropolyether compound having at least two alkenyl groups and a perfluoropolyether structure, (B) an organosilicon compound having at least two SiH groups, (C) a perfluoroparaffin or derivative in powder form, at least 80% by weight of which volatilizes off when held in a drier at 200° C. for 4 hours, and which has a melting point of at least 50° C., and (D) a hydrosilylation catalyst cures into a product that exhibits solvent resistance, chemical resistance, weather resistance, water repellency, oil repellency and heat resistance, and is improved in mold release and compression set.

Abstract: Fluoropolyether rubber compositions comprising (A) a polyfluorodialkenyl compound terminated with alkenyl groups, (B) a perfluoropolyalkenyl compound or a polyalkenylsiloxane compound, (C) a fluorine-modified organosilicon compound having at least two SiH groups, (D) a platinum group compound, and (E) hydrophobic silica powder are suited for injection molding, typically by LIMS. Rubber parts resulting from curing have heat resistance, chemical resistance, solvent resistance, low-temperature properties, high hardness and high strength.

Abstract: A crosslinkable fluororubber composition comprising (A) a liquid perfluoro compound having alkenyl groups and a divalent perfluorolakylene or perfluoropolyether structure, (B) a reinforcing filler, (C) a surface treating agent having a fluoroalkyl or fluoropolyalkyl ether group and a silanol group, (D) an addition reactive compound having hydrosilyl groups, and (E) a hydrosilyl or peroxide crosslinker is prepared by mixing components (A) to (C) to form a liquid or paste composition, adding component (D) thereto to form a millable composition, and mixing component (E) therewith. The composition is effectively roll workable and cures into products having excellent physical properties.

Abstract: A curable fluoropolyether rubber composition comprising (A) a straight-chain fluoropolyether compound having at least two alkenyl groups in a molecule and a perfluoropolyether structure in the backbone, (B) an organosilicon compound having at least two hydrosilyl groups in a molecule, (C) a compound containing at least one fluorine atom and at least one benzene ring in a molecule, free of a polar group, having a melting point of at least 50° C., in powder form, and (D) a hydrosilylation catalyst cures into a rubber product having solvent resistance, chemical resistance, improved mold release property and satisfactory compression set.

Abstract: In an injection mold comprising a cavity and a gate for feeding a molding material into the cavity, the molding material fed from the gate into the cavity is divided into two streams that flow through the cavity and then meet at a confluent point so that the molding material portions are joined together along a joint plane. Two air vent gates are spaced apart from the confluent point so as to provide a larger area of the joint plane. Articles having a good outer appearance and improved strength at the material joint can be consistently manufactured to a high precision.

Abstract: A fluororubber composition comprising (A) a liquid perfluoro compound having at least two alkenyl groups and a divalent perfluorolakylene or perfluoropolyether structure, (B) a compound capable of addition reaction having at least two hydrosilyl groups, components (A) and (B) being combined and precured in the presence of an addition reaction catalyst to form a precured base, (C) a reinforcing filler, and (D) a peroxide crosslinking agent containing an isopropyl monocarbonate group has improved solvent resistance, chemical resistance, heat resistance and low-temperature properties, as well as satisfactory rubber physical properties, especially strength.

Abstract: Rubber aircraft parts are made of the cured form of a curable composition comprising a perfluoropolyether polymer having a perfluoropolyether backbone and at least one reactive group, a crosslinking agent for crosslinking the polymer, and a silica filler having an average particle size of 0.001-10 &mgr;m. By providing dramatically improved sealability at low temperatures of −25 to −55° C., particularly during use in a dynamic state, and much improved resistance to amines and other chemicals, such rubber parts can ensure the reliable sealability of fluid line junctions in jet engines.

Abstract: A liquid fluoropolyether base rubber composition comprising (A) a linear fluoropolyether compound containing at least two alkenyl groups and having a perfluoroalkyl ether structure in its backbone, (B) a silica filler having a specific surface area of at least 100 m2/g and a bulk density of 100-200 g/l, (C) a curing amount of an organosilicon compound having at least two silicon-bound hydrogen atoms, and (D) a hydrosilylation catalyst is unlikely to thicken despite filler loading, is suitable for liquid injection molding and curable into products having improved mechanical properties as well as water repellency, oil repellency, solvent resistance, chemical resistance and weather resistance.

Abstract: A curable fluoropolyether rubber composition comprising (A) a straight-chain fluoropolyether compound having at least two alkenyl groups and a perfluoropolyether structure, (B) an organosilicon compound having at least two SiH groups, (C) a perfluoroparaffin or derivative in powder form, at least 80% by weight of which volatilizes off when held in a drier at 200° C. for 4 hours, and which has a melting point of at least 50° C., and (D) a hydrosilylation catalyst cures into a product that exhibits solvent resistance, chemical resistance, weather resistance, water repellency, oil repellency and heat resistance, and is improved in mold release and compression set.

Abstract: A crosslinkable fluororubber composition comprising (A) a polymer of the formula: Z-(Rf-Q)n-Rf-Z wherein n is an integer of at least 1, Rf is a divalent perfluoroalkylene or perfluorooxyalkylene radical, Q is a divalent organic radical, and Z is a monovalent organic radical, having a viscosity of at least 1,000 Pa·s at 25° C., (B) a reinforcing filler, and (C) a peroxide crosslinking agent is effectively roll milled and experiences minimal changes of viscosity after milling. Molded parts can be produced on a mass scale.

Abstract: A fluororubber composition comprising (A) a liquid perfluoro compound having at least two alkenyl groups and a divalent perfluorolakylene or perfluoropolyether structure, (B) a compound capable of addition reaction having at least two hydrosilyl groups, components (A) and (B) being combined and precured in the presence of an addition reaction catalyst to form a precured base, (C) a reinforcing filler, and (D) a peroxide crosslinking agent containing an isopropyl monocarbonate group has improved solvent resistance, chemical resistance, heat resistance and low-temperature properties, as well as satisfactory rubber physical properties, especially strength.

Abstract: A crosslinkable fluororubber composition comprising (A) a liquid perfluoro compound having alkenyl groups and a divalent perfluorolakylene or perfluoropolyether structure, (B) a reinforcing filler, (C) a surface treating agent having a fluoroalkyl or fluoropolyalkyl ether group and a silanol group, (D) an addition reactive compound having hydrosilyl groups, and (E) a hydrosilyl or peroxide crosslinker is prepared by mixing components (A) to (C) to form a liquid or paste composition, adding component (D) thereto to form a millable composition, and mixing component (E) therewith. The composition is effectively roll workable and cures into products having excellent physical properties.

Abstract: In an injection mold comprising a cavity and a gate for feeding a molding material into the cavity, the molding material fed from the gate into the cavity is divided into two streams that flow through the cavity and then meet at a confluent point so that the molding material portions are joined together along a joint plane. Two air vent gates are spaced apart from the confluent point so as to provide a larger area of the joint plane. Articles having a good outer appearance and improved strength at the material joint can be consistently manufactured to a high precision.