摘要:
A silicone rubber roll is characteristically prepared on a metallic center by forming a layer of the cured product of a silicone rubber composition which comprises (A) organopolysiloxane, in which the total amount of low molecular weight siloxanes having a degree of polymerization ranging from 3 to 20 is controlled to be at most 10,000 ppm, (B) reinforcing silica powder with a specific surface area of at least 50 m.sup.2 /g, (C) silicone elastomer particles with an average particle size of 200 .mu.m, in which the total amount of low molecular weight siloxanes having a degree of polymerization ranging from 3 to 20 is 2,000 ppm or less, and (D) a curing agent. The total amount of low molecular weight siloxanes having a degree of polymerization ranging from 3 to 20 within the cured product layer is controlled to be 2,000 ppm or less, since the elimination of the low molecular weight siloxanes having a degree of polymerization ranging from 3 to 20 proceeds effectively during the processes of the silicone rubber composition preparation, forming, and curing. Therefore, the obtained roll is extremely useful for various types of rolls utilized in copying machines which particularly need to avoid the low molecular weight siloxanes.
摘要:
The invention provides a semiconductive silicone rubber composition comprising (A) an organopolysiloxane containing at least two aliphatic unsaturated groups, (B) reinforcing silica powder having a specific surface area of at least 50 m.sup.2 /g, (C) a conductive agent, (D) a hydrocarbon oil having a heat loss of up to 30% at 200.degree. C./4 hours, and (E) a curing agent. Cured silicone rubber of the composition has a resistance of 1.times.10.sup.3 to 1.times.10.sup.12 .OMEGA. which remains stable for long-term use. The semiconductive silicone rubber composition is appropriate as a semiconductive roll stock for the manufacture of charging rolls, transfer rolls and developing rolls in business machines.
摘要:
The crosslinkable rubber composition of the invention is crosslinkable by hot air, and a hot-air crosslinked rubber sheet thereof has no scratch on the surface in a hardness test using a pencil of HB and has a compression set of not more than 70% after a heat treatment at 150° C. for 22 hours. The rubber composition comprises an ethylene/α-olefin/non-conjugated polyene random copolymer rubber comprising a specific vinyl end group-containing norbornene compound, a SiH group-containing compound having at least two SiH groups in one molecule, and if necessary, an addition reaction catalyst comprising a platinum group element and a reaction inhibitor.
摘要:
The crosslinkable rubber composition of the invention is crosslinkable by hot air, and a hot-air crosslinked rubber sheet thereof has no scratch on the surface in a hardness test using a pencil of HB and has a compression set of not more than 70% after a heat treatment at 150° C. for 22 hours. The rubber composition comprises an ethylene/α-olefin/non-conjugated polyene random copolymer rubber comprising a specific vinyl end group-containing norbornene compound, a SiH group-containing compound having at least two SiH groups in one molecule, and if necessary, an addition reaction catalyst comprising a platinum group element and a reaction inhibitor. The automobile weatherstrip, hose, rubber vibration insulator, belt, sealing material, expanded product, covered electric wire, electric wire joint, electric insulating part and household rubber product according to the invention comprise the above-mentioned rubber composition. The rubber composition has a high crosslinking rate and excellent productivity to produce crosslinked rubber molded products, is capable of undergoing hot-air crosslinking such as HAV or UHF and is capable of providing crosslinked rubber molded products having excellent compression set resistance, strength properties, heat resistance, weathering resistance and abrasion resistance.
摘要:
A rubber compound comprising (A) an organopolysiloxane having at least two alkenyl groups in a molecule and (B) reinforcing silica powder is blended with (C) silicone elastomer particles obtained by reacting an organohydrogenpolysiloxane with a vinyl group-containing organopolysiloxane such that the molar ratio of .tbd.SiH group to --CH.dbd.CH.sub.2 group ranges from 1.2 to 5 and (D) a platinum catalyst to form a silicone rubber composition which cures into a product having high rubber strength despite the inclusion of silicone elastomer particles. The composition finds typical use as silicone rubber parts in copying machines.
摘要:
The crosslinkable rubber composition of the invention is crosslinkable by hot air, and a hot-air crosslinked rubber sheet thereof has no scratch on the surface in a hardness test using a pencil of HB and has a compression set of not more than 70% after a heat treatment at 150° C. for 22 hours. The rubber composition comprises an ethylene/α-olefin/non-conjugated polyene random copolymer rubber comprising a specific vinyl end group-containing norbornene compound, a SiH group-containing compound having at least two SiH groups in one molecule, and if necessary, an addition reaction catalyst comprising a platinum group element and a reaction inhibitor. The automobile weatherstrip, hose, rubber vibration insulator, belt, sealing material, expanded product, covered electric wire, electric wire joint, electric insulating part and household rubber product according to the invention comprise the above-mentioned rubber composition. The rubber composition has a high crosslinking rate and excellent productivity to produce crosslinked rubber molded products, is capable of undergoing hot-air crosslinking such as HAV or UHF and is capable of providing crosslinked rubber molded products having excellent compression set resistance, strength properties, heat resistance, weathering resistance and abrasion resistance.
摘要:
A conductive fluorosilicone composition including: (A) an organopolysiloxane having a polymerization degree of at least 100 and represented by the following average compositional formula: Ra(CF3CH2CH2)bSiO[4-(a+b)]/2 (1) wherein R is an unsubstituted monovalent hydrocarbon group, a is a number ranging from 0.8 to 1.8, b is a number ranging from 0.2 to 1.2, and a and b are numbers satisfying a+b=1.95 to 2.05 and b/(a+b)=0.1 to 0.6, (B) a graphitization-treated carbon black, and (C) a curing agent. The composition can give, upon curing, a cured product having a small tension-set, a good rubber-elasticity and an excellent heat-resistance, as well as a desired conductivity and a good solvent-resistance.
摘要:
An addition curing type silicone rubber composition comprising an aliphatic unsaturated group-containing organopolysiloxane, an organohydrogenpolysiloxane and a platinum series catalyst is further blended with a triazine or sulfide control agent to provide a composition which is stable and resistant against premature gelation at room temperature and thus has long-term storage stability. Heating causes the composition to be quickly vulcanized at an acceptable rate into a silicone rubber having satisfactory physical properties.
摘要:
An objective of the present invention is to provide a rare earth metal-based permanent magnet with improved adhesion properties. A rare earth metal-based permanent magnet of the present invention as a means for achieving the objective has a laminated plating film, and is characterized in that the plating film comprises as an outermost surface layer a SnCu alloy plating film having a film thickness in a range from 0.1 μm to 2 μm, the composition of the SnCu alloy plating film is 35 mass % or more but less than 55 mass % of Sn and the rest being Cu, and a base plating film having two or more layers including at least a Ni plating film and a Cu plating film which are formed as the lower layer under the SnCu alloy plating film, and among the base plating film, the Ni plating film is located just below the SnCu alloy plating film. A joined structure fabricated using the rare earth metal-based permanent magnet of the present invention exhibits favorable initial adhesion strength when combined with a silicone-based adhesive, and is less deteriorated in adhesion strength even after a moisture resistance test.
摘要:
The invention relates to the use of a precipitated silica, pretreated by at least one organosilane hydrophobic compound or one hydrophobic silicone oil, as a reinforcing filler for silicone elastomer, the pretreated silica being incorporated in the silicone elastomer by cold mixing and having the following features: —a BET specific surface ranging from 50 to 450 m2/g, —a water wettability lower than 80, —a sulfur content lower than 0.1% by weight. The invention is directed to the curable silicone elastomer composition thus obtained.