Abstract: The present invention provides a polymeric-type antistatic agent containing a polymer composition consisting of a polymeric-type antistatic agent containing a resin or/and an elastomer as a main component thereof; or/and a thermoplastic resin having a polar group or/and an elastomer having the polar group. At least one kind of an anion-containing salt, having a fluoro group and a sulfonyl group, is added to the polymer composition without intermediary of a medium consisting of a low-molecular-weight polyether-containing compound or a low-molecular-weight polar compound whose number-average molecular weight is not more than 5000. The present invention also provides a composition, for a conductive roller or the like, containing polymer components and the polymeric-type antistatic agent dispersed in the polymer components.

Abstract: A modified natural rubber is disclosed, which is obtained by modifying a deproteinized natural rubber having a nitrogen content of less than 0.10% by weight. A process for improving the graft ratio and the graft efficiency of natural rubber and a process for improving the epoxidation ratio of natural rubber are also disclosed. The modified natural rubber of the present invention has a high modifying efficiency and thus shows an excellent modifying effect. It is also useful as a means for preventing allergy.

Abstract: A conductive elastomer composition having rubber-like elasticity and flexibility and thermoplastic-resin-like moldability and realizing a high conductivity. The conductive elastomer composition includes a thermoplastic elastomer composition (A) containing a compound (A1) composed of a thermoplastic resin and/or a thermoplastic elastomer and a compound (A2), composed of a crosslinkable rubber and/or a crosslinkable thermoplastic elastomer, dispersed in the compound (A1) by dynamically crosslinking the compound (A2); and an ionic-conductive agent (B), containing a metal salt and a polyether-containing block copolymer resin, dispersed in the thermoplastic elastomer composition (A). The conductive elastomer composition may contain carbon black (C).

Abstract: Disclosed are a polymer composition comprising (A) at least one thermoplastic elastomer selected from the group consisting of a hydrogenated styrene-isoprene-styrene block copolymer, a hydrogenated styrene-butadiene-styrene block copolymer and a styrene-ethylene-ethylene-propylene-styrene block copolymer, (B) a rubber component containing an ethylene-propylene-diene rubber, and (C) a softener, or a polymer composition further comprising (a) an olefin polymer and, if necessary, (D) carbon black, wherein the amount of the component (C) is not less than 200 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B) or (A), (B)and (a), and at least portion of the rubber component (B) is crosslinked by dynamic crosslinking, and a sealant made by using the same.

Abstract: A high specific-gravity EPDM composition consisting of a mixture of EPDM containing diene at less than 4.5 wt % and ethylene at not less than 58 wt % nor more than 80 wt % and having a Mooney viscosity ML1+4 not less than 50 nor more than 170 at 125° C. and a powdery material, containing powder whose specific gravity is not less than 12 as a main component thereof, added to the EPDM at not less than 80 wt % nor more than 97.5 wt % of a whole amount of the high specific-gravity EPDM composition.

Abstract: The present invention provides a thermoplastic resin composition having a high specific gravity, flexibility and excellent processability that can be used as a material for forming various articles requiring both massiveness and flexibility. This thermoplastic resin composition contains 2.5 to 15 wt % of a styrene-based thermoplastic elastomer and 85 to 97.5 wt % of tungsten powder, and an molded article is obtained by melting and kneading this thermoplastic resin composition. This article can be used preferably as a balance weight attached to a wheel of an automobile, sports goods or the like.

Abstract: Disclosed are a polymer composition comprising (A) at least one thermoplastic elastomer selected from the group consisting of a hydrogenated styrene-isoprene-styrene block copolymer, a hydrogenated styrene-butadiene-styrene block copolymer and a styrene-ethylene-ethylene-propylene-styrene block copolymer, (B) a rubber component containing an ethylene-propylene-diene rubber, and (C) a softener, or a polymer composition further comprising (a) an olefin polymer and, if necessary, (D) carbon black, wherein the amount of the component (C) is not less than 200 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B) or (A), (B) and (a), and at least portion of the rubber component (B) is crosslinked by dynamic crosslinking, and a sealant made by using the same.

Abstract: The present invention relates to a balance weight 10 for a vehicle wheel, including: (1) a metal clip 14 with a hook portion 11 having a cross-sectional shape corresponding to a flange edge portion of a wheel, and a leg portion 13 for retaining a weight made of a resin composition having high specific gravity, which is capable of independently close-contacting and fixing to the flange edge portion, and (2) a weight 12 made of a thermoplastic resin in including 2.5 to 8.0% by weight of a thermoplastic elastomer and 97.5 to 92% by weight of tungsten powder, which is attached to the leg portion 13.

Abstract: Disclosed is a low modulus of elasticity-rubber composition, which is useful for sealing a telecommunication cable closure even in low temperature range, utilizing an ethylene-propylene-diene rubber. Said low modulus of elasticity-rubber composition comprising (1) an ethylene-propylene-diene rubber [Mooney viscosity (100° C.): 90 to 130° C., diene: ethylidenenorbornene, iodine value: not more than 20, ethylene content: not more than 55% based on the total amount of ethylene and propylene] and (2) a softener [pour point: not more than −40° C.

Abstract: A process is disclosed, by which protein can be removed easily and efficiently from natural rubber latex so that deproteinized natural rubber latex can be produced with high productivity and low cost. Particularly, a process for the production of deproteinized natural rubber latex is disclosed, which comprises treating natural rubber latex with a proteolytic enzyme and a surfactant to decompose protein in natural rubber latex, washing the treated natural rubber latex in the presence of a salt. According to the process, deproteinized natural rubber latex useful as a counter-allergy material having stable qualities can be produced easily with high productivity and low cost.

Abstract: A method for producing a formed product of deproteinized natural rubber latex capable of reducing a content of an allergen in a natural rubber latex material to a level sufficient to keep the latex from being harmful to the human body without decreasing yields of the product and deteriorating formability of the latex. In the method, cleaning removal of a non-rubber content is carried out after each of protein decomposition, prevulcanization and forming. An aqueous alkali solution, ammonia, water containing free chlorine in an amount of 0.005 to 0.02% by weight or alcohol-water mixed liquid containing alcohol in an amount of 5 to 80% by weight is used as cleaning liquid for the cleaning removal. The method is suitably applied to production of a natural rubber product such as a rubber glove, a condom, a catheter, a foam rubber material and the like.

Abstract: A process is disclosed, by which protein can be removed easily and efficiently from natural rubber latex so that deproteinized natural rubber latex can be produced with high productivity and low cost. Particularly, a process for the production of deproteinized natural rubber latex is disclosed, which comprises treating natural rubber latex with a proteolytic enzyme and a surfactant to decompose protein in natural rubber latex, washing the treated natural rubber latex in the presence of a salt. According to the process, deproteinized natural rubber latex useful as a counter-allergy material having stable qualities can be produced easily with high productivity and low cost.

Abstract: Described is a process for the production of depolymerized natural rubber, which makes it possible to obtain, at high reaction efficiency, of depolymerized natural rubber in the liquid form and having a narrow molecular weight distribution; and also a process for the production of depolymerized natural rubber which is free from odor or coloring peculiar to natural rubber and is also free from the danger of immediate allergy derived from protein.The process according to the present invention comprises adding a carbonyl compound to a natural rubber latex, and then subjecting the resulting natural rubber to air oxidation in the presence of a radical forming agent or adding a carbonyl compound to the latex of deproteinized natural rubber and then subjecting the deproteinized natural rubber to air oxidation optionally in the presence of a radical forming agent.

Abstract: A depolymerized natural rubber having a number-average molecular weight of from 2,000 to 50,000 obtained by the depolymerization of a deproteinized natural rubber. A process for the preparation of a depolymerized natural rubber comprises dissolving a deproteinized natural rubber into an organic solvent so as to give a concentration of from 1 to 30% by weight and then carrying out air oxidation of the resulting solution in the presence of a metallic catalyst. The depolymerized natural rubber can provide the same physical properties as ordinary vulcanized rubbers, exhibits no odor or color characteristic to natural rubbers and causes no immediate allergy induced by protein.

Abstract: A means for stabilizing a deproteinized natural rubber latex is disclosed, comprising adding a stabilizer selected from the group consisting of (a) an anionic surfactant, (b) an amphoteric surfactant, (c) a nonionic surfactant, (d) a nonionic or amphoteric oligomer or polymer, and (e) an anionic oligomer or polymer. By adding the stabilizer, the mechanical stability of a deproteinized natural rubber latex can be markedly improved.

Abstract: This invention presents a rubber composition wherein a determined amount of protein is mixed with unvulcanized rubber. Rubber products made of this rubber composition have sufficient strength for practical use and are harmless to human bodies. The rubber composition of the invention not requiring vulcanizing process is advantageous in eliminating the need of large-scale vulcanizing equipment. Combined use of a curing agent and protein will increase modulus higher than using the curing agent alone.

Abstract: A process for producing raw rubber from a deproteinized natural rubber is disclosed, which comprises coagulating rubber particles in the deproteinized natural rubber latex by: (1) adding a nonionic surfactant having a cloud point of from 20.degree. to 100.degree. C. and a molecular weight of 300 or more to the deproteinized natural rubber latex and heating the latex to a temperature not lower than the cloud point of the nonionic surfactant; or (2) adding a coagulation assistant selected from the group consisting of: (a) an anionic surfactant, (b) an amphoteric surfactant, (c) a nonionic surfactant, (d) a nonionic or amphoteric oligomer or polymer, and (e) an anionic oligomer or polymer, to the deproteinized natural rubber latex; and then recovering the coagulated rubber particles. According to the process of the present invention, raw rubber containing substantially no metal ion can be produced with a high efficiency.

Abstract: The invention presents a compressive hemostatic belt which is easy to handle and is disposable. A balloon 5 inflatable by filling with fluid is mounted on a specific position of a strip 1 made of non-elastic or low-elastic fiber cloth or the like through mounting means, and a pump 8 and a pressure gauge 9 are connected to the balloon 5 through a check valve 6. The balloon 5 is filled with a fluid by manipulating the pump 8 while observing the pressure gauge 9 to inflate the balloon 5, so that only the area where bleeding is to be stopped is put under pressure. Since the balloon 5 is inflated only on the specified area, a piece of hard material 4 may be placed between the balloon 5 and the strip 1. A non-elastic reinforcing member 11 inserted on the opposite side of the balloon 5 can be varied, or the confronting portion of the strip 1 against the balloon 5 can be formed of a non-elastic reinforcing member stronger than the materials of other portions of the strip.

Abstract: The glove according to the present invention has, at least partially, a laminated part 2 in which a plurality of different types of rubbers are successively laminated. In the laminated part 2, the lowermost layer is a natural rubber layer, and the top surface layer is an oil-resistant rubber layer (for example, an acrylonitrile-butadiene rubber layer). The glove manufacturing method according to the present invention comprises the steps of immersing a glove mold in natural rubber latex containing a heat-sensitive coagulant to form a coating of the lowermost layer on the mold surface, and immersing at least a part of the lowermost layer in another rubber latex different from the first-mentioned rubber latex. The glove of the present invention has high strength and is economical and excellent in oil resistance and solvent resistance.

Abstract: A compressive hemostatic belt which is easily operable and thrown away after use, incorporates a strip (1) in the form of a nonstretch or low-stretch textile fabric, and a bag (5) expansible by being filled with fluid that is attached to the strip at a predetermined position by an attaching device. A pump (8) and a pressure gauge (9) are connected to the bag (5) attached at the predetermined position on the strip (1), so that the bag is expanded by operating the pump so as to fill the bag (5) with a suitable fluid while watching the pressure gauge (9). The bag thus presses down on an area (A) where bleeding is to be stopped.