摘要:
A silicone rubber composition comprising (A) 100 parts by weight of an organopolysiloxane having a degree of polymerization of 100 or higher and having at least two silicon-bonded alkenyl groups in the molecule; (B) from 3 to 100 parts by weight of a wet silica having the following properties: specific surface area (the BET method) of 50 m2/g or larger, specific surface area (the BET method)/specific surface area (the CTAB method) of from 1.0 to 1.3, and water content of 4% or lower; and (C) an effective amount of a curing agent. The silicone rubber composition can be obtained without foaming even in hot air vulcanization and even if wet silica is used therein, and the silicone rubber composition gives a silicone rubber excellent in electrical properties such as electrical insulating properties.
摘要:
A process for producing a urethane-modified polyisocyanurate foam having excellent characteristics such as flame retardancy, heat resistance and low smoking property, and further having improved initial adhesion, particularly adhesion after a relatively long period of time, to a facing material particularly a flexible facing material, by using water as a blowing agent, is provided. A polyisocyanate compound component, a polyol component, water and a morpholine compound are reacted in the presence of a trimerization catalyst for isocyanates.
摘要:
A urethane-modified polyisocyanurate foam obtained by reacting (A) a polyisocyanate compound component, (B) a polyol component, containing a modified phenolic resin obtained by adding 20 to 100 parts by weight of a polyhydric alcohol or its alkylene oxide adduct to 100 parts by weight of a benzylic ether type phenolic resin and heating under a reduced pressure, in an amount of at least 3 wt % to the total resin component, (C) water and (D) a foam stabilizer comprising a mixture of at least 2 silicone type surfactants having different surface tensions wherein a surfactant having a higher surface tension has a surface tension of higher than 22 dyne/cm and a surfactant having a lower surface tension has a surface tension of at most 22 dyne/cm, in the presence of (E) a urethane-forming catalyst and/or a trimerization catalyst.
摘要:
This invention provides a pitch fiber bundle for carbon fibers of small size, a carbon fiber bundle, and a method for the production thereof, i.e. a method for the production of carbon fibers of a small size, a pitch fiber bundle, and a carbon fiber bundle at a lower cost with higher productivity than usual. The method for the production of pitch type carbon fibers according to this invention comprises dividing a plurality of pitch fibers into not less than two bundles, intertwining the bundles by exposure to currents of air thereby forming a first fiber bundle, binding a plurality of such first fiber bundles, and again intertwining the bound pitch fiber bundles by exposure to currents of air thereby forming a second fiber bundle.
摘要:
In a silicone rubber composition comprising an organopolysiloxane having at least two aliphatic unsaturated groups and a curing agent, metallized particles of inorganic material or organic resin are effectively dispersed to give a conductive composition which cures into a conductive silicone rubber part having a low and stable volume resistivity.
摘要:
2-Sulfamoylbenzoic acid derivatives of general formula (I): which have both an antagonistic effect on the leukotriene D4 receptor and an antagonistic effect on the thromboxane A2 receptor and salts thereof, pharmaceuticals, anti-allergic agents and leukotriene-thromboxane A2 antagonistic agents containing them as an active ingredient.
摘要:
A pneumatic tire for a front wheel of a motorcycle comprises a pair of bead cores, a radial carcass toroidally extending between the pair of bead portions, a belt disposed on a radially outer surface of the carcass, and a tread portion disposed thereon, wherein the carcass is comprised of at least one carcass ply containing organic fiber cords, and the belt is a spiral belt layer formed by spirally winding a continuous rubberized cord or a continuous ribbon-shaped body containing plural cords therein in a widthwise direction of the tire, and the tread portion has a two-layer structure comprised of a cap rubber layer and a base rubber layer in at least a central region in the widthwise direction of the tire, or a reinforcing layer is disposed inside an innermost carcass ply or on an inner surface of an innerliner, or the bead core is a helically wound laminate of a single steel wire having a polygonal shape at a section of the bead core in the radial direction.
摘要:
An improved double-layered rubber laminate is proposed, which is an integral body consisting of a first layer of an organopolysiloxane-based rubber composition and a second layer of an acrylic rubber-based composition. When the acrylic rubber in the latter composition is not a conventional acrylic rubber but a copolymeric rubber of a (meth)acrylate ester monomer and an organosilicon monomer having, in a molecule, at least one silicon-bonded vinyl group and an ethylenically unsaturated group other than silicon-bonded vinyl groups, such as 3-methacryloxypropyl, very firm bonding can be obtained between the layers by the co-vulcanization of the laminated layers to exhibit very high resistance against delamination.
摘要:
A polycrystalline diamond is prepared by chemical vapor deposition (step 101). A surface of the polycrystalline diamond is metallized (step 102). The metallized surface of the polycrystalline diamond is grooved with a YAG laser (step 103). A wedge or the like is driven into the grooves of the polycrystalline diamond to pressurize the same, whereby the polycrystalline diamond is divided along the grooves (step 104). Alternatively, a surface of a polycrystalline diamond prepared by chemical vapor deposition is grooved with a YAG laser (step 112), so that the surface of the polycrystalline diamond is metallized (step 113) after the grooving.
摘要:
A conductive rubber composition is prepared by blending (A) a rubber composition including natural and/or synthetic rubber and conductive carbon black, with (B) a silicone rubber composition including an organopolysiloxane having the average composition formula: R.sub.n SiO.sub.(4-n)/2 wherein R is a hydrocarbon group and n is a positive number of from 1.95 to 2.05. This rubber composition and cured products thereof have stable electric resistivity in the semiconductive range and are thus suitable as rubber roll members in business machines.