摘要:
A foam rubber composition and a method for making same which is foamable to a high degree and a molded product made from the foam rubber composition wherein the compositions has: (A) a low-molecular Ethylene-propylene-5-ethylidene-2-norbornene terpolymer having a Mooney viscosity (ML.sub.1+4 at 100.degree. C.) of 20 to 40, an ethylene/propylene ratio by weight of 65/35 to 50/50, an iodine value of 20 to 30, and a Q value (Mw/Mn) not exceeding 3 as determined by gel permeation chromatography; (B) a high-molecular ethylene-propylene-5-ethylidene-2-norbornene terpolymer having a Mooney viscosity (ML.sub.1+4 at 100.degree. C.) of 100 to 300, an ethylene/propylene ratio by weight of 65/35 to 50/50, an iodine value of 20 to 30 and a Q value (Mw/Mn) of 6 to 10; (C) a vulcanizing system agent containing sulfur as a vulcanizer, and zinc carbamate and sulfenamide as accelerators; and (D) a foaming agent containing N, N'-dinitrosopentamethylenetetramine and urea.
摘要:
A formed rubber extruded product which is formed of a vulcanizate of a rubber blend comprising a sulfur-vulcanizable ethylene-propylene-type rubber (EPDM) as a starting rubber and a pyrolytic foaming agent. The vulcanizate has a specific gravity of from 0.9 to 1.0 and a surface roughness (RZD) of 14 micrometers or less. The rubber blend contains the pyrolytic foaming agent in the form of an inorganic powder-supported foaming agent. A particle diameter of the inorganic powder in the inorganic powder-supported foaming agent is approximately 9 micrometers or less, and a particle diameter of the pyrolytic foaming agent is approximately 8 micrometers or less. Further, crystalline PE is contained in an amount of from 6 to 30 parts per 100 parts of EPDM. The foamed rubber extruded product of the present invention can be produced by the extrusion at a high rate.
摘要:
A foamed rubber blend comprising an EPDM is polymer blend comprising at least one high molecular weight component and at least one low molecular weight component is provided. The high molecular weight component has a weight average molecular weight (Mw) in a range of from about 400,000 to about 800,000 and a molecular weight distribution index (Mw/Mn) in a range of from about 5.5 to about 9.5. The low molecular weight component has a weight average molecular weight (Mw) in a range of from about 150,000 to about 500,000 and a molecular weight distribution index (Mw/Mn) in a range of from about 1.5 to about 5.5. The EPDM rubber has an overall weight average molecular weight (Mw) in a range of from about 200,000 to about 700,000. The ratio of the polymer blend in the foamed rubber blend is in a range of from about 33 wt % to about 60 wt %. The present invention is also directed to an article formed from a sulfur-vulcanized EPDM rubber blend having a compression set according to JIS K 6301 of not more than about 24%.
摘要:
A rubber composition, including α,β-ethylenically unsaturated nitrile-conjugated diene copolymer rubber (A) having number average molecular weight of 50,000 to 150,000, α,β-ethylenically unsaturated nitrile-conjugated diene copolymer rubber (B) having number average molecular weight of 1,000 to 20,000, ethylene-α-olefin copolymer rubber (C), and a graft copolymer (D); wherein said graft copolymer (D) is obtained by performing graft copolymerization on a mixture of an aromatic vinyl compound and an α,β-ethylenically unsaturated nitrile monomer with an ethylene-propylene-unconjugated copolymer, and a content of structure units of said ethylene-propylene-unconjugated copolymer is 20 to 70 wt %; a ratio of the graft copolymer (D) with respect to 100 parts by weight in total of said rubber (A), rubber (B) and rubber (C) is 1 to 30 parts by weight; and a composition ratio of the rubber (A), rubber (B) and rubber (C) is rubber (A): 20 to 79 wt %, rubber (B): 1 to 30 wt %, and rubber (C): 20 to 50 wt %, is subjected to vulcanization molding, consequently, vulcanizate of the rubber composition having excellently balanced ozone resistance, flexing fatigue resistance and oil resistance can be provided.
摘要:
Disclosed is (1) a rubber composition used for molding a glass-run equipped with a urethane lubricating layer on the sliding area of the glass, which comprises an EPDM and an adhesive modifier, wherein the adhesive modifier comprises glycidyl ether, and a metal hydroxide of a metal selected from metals of the III B group and the II A group and (2) a rubber composition used for molding a glass-run equipped with a urethane lubricating layer on the sliding area of the glass, which comprises an EPDM and an adhesive modifier, wherein the adhesive modifier comprises a glycidyl ether, a metal hydroxide of a metal selected from metals of the III B group and the II A group and an amine-containing compound as an epoxy group ring-opening accelerator, and further a glass-run comprising the above rubber composition.
摘要:
A mold for a metal hot-runner injection molding machine includes a movable mold plate, a fixed mold plate having a nozzle for injecting molten metal into said cavity, and a heating device disposed outside the nozzle for heating metal. A gate cut portion is situated in the nozzle between the heating device and the tip. A temperature measurement device is arranged adjacent to the gate cut portion for measuring the temperature of the metal in the gate cut portion. A heating control device is connected to the heating device for controlling a temperature of the nozzle on a basis of the temperature measurement device. A heat insulation device is arranged on the nozzle to cover at least an area where the gate cut portion is formed. By controlling the temperature of the nozzle, metal injection molding without runner can be made.
摘要:
A process of producing a surface-modified weather strip for automobiles is disclosed. The process comprises coating a silicone emulsion composition formed by mixing and dispersing the components (A) to (D) as defined hereinabove on the surface of a weather strip for automobiles, and heat curing the coating at a temperature of from 50.degree. to 250.degree. C. The weather strip thus produced has excellent durability, soundproof property, weather resistance, non-sticking property, antifreezing property, slipping property, abrasion resistance, etc.
摘要:
A duplex eutectic silicon alloy including 30-70 weight % silicon, 10-45 weight % nitrogen, 1-40 weight % aluminum, and 1-40 weight % oxygen has a eutectic structure comprising a β′-sialon phase and an ο′-sialon phase. The alloy is produced by controlling cooling at a rate of 50° C. or less per minute in combustion synthesis. A ductile sintered product capable of replacing steel in various applications can be produced by placing a compact composed of a powder of the alloy in a sintering furnace which can supply a heat quantity at least ten times the heat capacity of the compact; and sintering the compact at a pressure at least as great as atmospheric pressure, within a nitrogen atmosphere in which the silicon gas mole fraction is 10% or more, and at a temperature within the range from 1400° C. to 1700° C.
摘要:
A rubber composition includes α,β-ethylenically unsaturated nitrile-conjugated diene copolymer rubber (A), α,β-ethylenically unsaturated nitrile-conjugated diene copolymer rubber (B), ethylene-α-olefin copolymer rubber (C), and a graft copolymer (D). The graft copolymer (D) is obtained by performing graft copolymerization on a mixture of an aromatic vinyl compound and an α,β-ethylenically unsaturated nitrite monomer with an ethylene-propylene-unconjugated copolymer. A content of structure units of the ethylene-propylene-unconjugated copolymer is 20 to 70 wt %, a ratio of the graft copolymer (D) with respect to 100 parts by weight in total of said rubber (A), rubber (B) and rubber (C) is 1 to 30 parts by weight. A composition ratio of the rubber (A), rubber (B) and rubber (C) is rubber (A): 20 to 79 wt %, rubber (B): 1 to 30 wt %, and rubber (C): 20 to 50 wt %.
摘要:
In a method for manufacturing a mold of a metal hot-runner injection molding machine, a temperature gradient of metal disposed in a nozzle between a heating device of the nozzle and a tip of the nozzle is measured. Then, an area in the nozzle is selected based on the measurement of the temperature gradient such that the metal in the nozzle upon a mold opening has a temperature at which a solidified condition of the metal can be stably maintained, where the temperature is close to a melting temperature of the metal. A gate cut portion is determined in the area.