Abstract: A thermoplastic composition comprising a polycarbonate, a polycarbonate-polysiloxane copolymer, an impact modifier composition comprising ABS or BABS, a second impact modifier different from BABS or ABS, and an aromatic vinyl copolymer is disclosed. The thermoplastic composition has improved molding capability.

Abstract: A process for preparing a rubber comprising polymeric composition, and the resulting compositions, and certain isoprene comprising interpolymers.

Abstract: A profile gasket has a locking part below a gasket base for mounting the gasket to a target body such as a refrigerator door. The gasket also has a sealing portion and an elastic support for elastically supporting the sealing portion to the gasket base. The gasket is made of a thermoplastic resin having a preferred composition.

Abstract: A backbone modified polymer comprising the reaction product of an elastomeric polymer and a sulfide modifier represented by Formula 1: AS—Y-Zm (Formula 1), and wherein Y is (C12-C100) aralkyl, (C12-C100) aryl, (C12-C100) alkyl, or (C12-C100) dialkylether (alkyl-O-alkyl), and wherein each may be optionally substituted with (C1-C4alkyl, (C1-C4alkoxy, (C7-C16aryl, (C7-C16 aralkyl, nitrile, amine, NO2, alkoxy, or thioalkyl; S is sulfur; A is hydrogen, —(S)p—R1 or -MR2R3R4; Z is —SH, —S-MR5R6R7, —S—(S)p—R8, —NR9R10, —NR11COR12, —O—CO—R13, —NCO, or —COOR14; M is silicon or tin; N is nitrogen; O is oxygen; m is the number one, two or three; p is the number one, two, three, four or five; R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13 and R14 are the same or different, and are each, independently, selected from hydrogen (H), (C1-C16) alkyl, (C6-C16) aryl, (C7-C16) aralkyl or (C3-C30) tri(hydrocarbyl)silyl, and wherein the hydrocarbyl groups are each independently selected from (C1-C16) alkyl, (C6-C16) aryl, or

Abstract: A resin composition for metal plating provides a molded article exhibiting excellent metal plating adhesion strength and chemical resistance, while having excellent productivity. A metal-plated molded article can also be made from such a resin composition. The resin composition for metal plating includes 50-90% by mass of Component (A) and 10-50% by mass of Component (B), the total of Component (A) and Component (B) being 100% by mass, wherein Component (A) is a polypropylene resin, and Component (B) is a rubber-reinforced vinyl resin obtained by polymerizing a vinyl monomer in the presence of a rubber-like polymer, or a mixture of the rubber-reinforced vinyl resin and a (co)polymer of the vinyl monomer. The composition may further include 0.5-30 parts by mass of a compatibilizer (C) per 100 parts by mass of the total of Component (A) and Component (B). Component (B) is preferably a non-diene rubber-reinforced resin.

Abstract: A method for producing a polymer for oil-resistant rubber, which comprises adding, to an aqueous dispersion of an unsaturated nitrile-conjugated diene copolymer (component A), a monomer composition (component B) containing at least one kind of monomer selected from the group consisting of a nitrile group-containing monomer (component B-1), a (meth)acrylic acid ester monomer (component B-2) and an aromatic vinyl compound monomer (component B-3), and conducting a polymerization reaction in a state that the ratio of the conjugated diene monomer present in the system, to the total monomers present in the system is controlled at 10 mol % or less.

Abstract: Elastomeric compositions comprising at least one C4 to C7 monoolefin elastomer, at least one polyalphaolefin, and optionally at least one hydrocarbon polymer additive are disclosed. The PAO comprises oligomers of one or more C2 to C20 alpha-olefins having a kinematic viscosity at 100° C. of 3 to 3000 cSt and a Mw/Mn of less than 4. In one aspect, the elastomeric composition may have improved flex fatigue properties and have a fatigue life of 450,000 Kc or more as measured by ASTM D 412 die C. In another aspect, an elastomeric composition may have improved impermeability and have a permeation coefficient at 40° C. of 160 cc*mm/(m2?day) or less.

Abstract: Seals and sealing members are formed from a composition generally comprising a first elastomeric material and a second elastomeric material, wherein the second elastomeric material comprises a dispersion of nanosized particles disposed within a polymer matrix of the second elastomeric material. Preferred first and second elastomeric materials are fluoroelastomers, and preferred nanosized particles are fluoropolymers. The nanosized particles are sized less than about 100 nm. The composition comprises about 0.2 to 65 percent by weight of first elastomeric material, about 20 to 95 percent by weight of second elastomeric material, and about 10 to 90 percent by weight particles based on the total weight of the particles and the second elastomeric material. The composition can be used to form annular O-ring seals placed within rotary cone bits used for drilling subterranean formations, and can be used to form a selected portion of the seal or the entire seal.

Abstract: A flame retardant thermoplastic composition comprising in combination a polycarbonate component; an impact modifier composition, the components of the impact modifier composition comprising a) a bulk polymerized ABS, and b) an impact modifier different from the ABS; an ungrafted rigid copolymer; and a flame retardant. The compositions have an improved balance of physical properties such as impact strength and flow, while at the same time maintaining their good flame performance.

Abstract: Novel crosslinkable compositions based on elastomers, at least one of which has carboxyl and/or carboxylate groups, are provided, these crosslinkable compositions containing special unsaturated organic salts of metal ions and a crosslinking system which acts as a free radical donor. Crosslinked elastomers which have excellent physical properties are obtainable therefrom. The novel crosslinkable compositions have a wide range of uses.

Abstract: Resin beads having an average particle size of from 0.001 mm to 10 mm and containing a continuous phase and a particulate dispersed phase are described. The continuous phase includes elastomeric polymers; the dispersed phase includes homopolymers and/or copolymers containing repeat units resulting from the polymerization of one or more aryl polymerizable monomers. The unexpanded polymer resin beads can be prepared by dispersing an organic phase containing elastomeric polymers and one or more monomers, into droplets and polymerizing the monomers in the organic droplets in a low shear flow pattern. The beads can be impregnated with blowing agents, expanded and can be used to make molded articles. Resin beads having a continuous phase comprising a nitrile rubber, and a dispersed phase comprising one or more homopolymers and/or copolymers containing repeat units resulting form the polymerization of one or more aryl polymerizable show prolonged retention of blowing agents in unexpanded form.

Abstract: The present invention relates to hydrogenated carboxylated nitrile-butadiene rubber (HXNBR), which contain molecularly dispersed triphenylphosphine, and which is useful as a cross-linking agent for elastomers, plastics and/or adhesive systems. The present invention also relates to products which are obtainable from the HXNBR having molecularly dispersed triphenylphosphine and elastomer, plastics and/or adhesive systems, a composition containing a HXNBR having molecularly dispersed triphenylphosphine and further non-molecularly dispersed activators, a process for the preparation of the composition as well as the use of HXNBR having molecularly dispersed triphenylphosphine, as an elasticizing agent for elastomer, plastics and/or adhesive systems.

Abstract: A flame retardant thermoplastic composition comprising in combination a polycarbonate component; an impact modifier composition, the components of the impact modifier composition comprising a) a bulk polymerized ABS, and b) an impact modifier different from the ABS; and a flame retardant. The compositions have an improved balance of physical properties such as impact strength and flow, while at the same time maintaining their good flame performance.

Abstract: Swellable compositions and methods of using and controlling them are disclosed. In certain examples, the swellable composition may comprise an active phase responsive to swell upon exposure to a swelling fluid. In some examples, the active phase of the swellable composition is effective to deswell in response to an applied stimulus in the presence of the swelling fluid. In other examples, the swellable composition may further comprise a passive phase responsive to swell to a lesser degree than the active phase upon exposure to the swelling fluid. Devices and systems using the swellable compositions are also described.

Abstract: A polycarbonate such as aliphatic/aromatic polycarbonate comprises repeating structural carbonate units of the formula (H-1): in which Rh is a radical having the formula (H-2): wherein each of R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23, R24, R25, R26, R27, and R28 is independently a hydrogen, a C1-C6 alkyl group, or a halogen substituted C1-C6 alkyl group. The polycarbonate, and a thermoplastic composition thereof, have improved thermal stability, cost-effectiveness, and exhibit improved manufacturability such as, for example, minimum cyclic carbonate formation and minimum amine acceptor requirement.

Abstract: An improved polymerization and work-up process makes it possible to produce specific nitrile rubbers which have a specific calcium and chloride content and have a particularly high storage stability.

Abstract: A thermoplastic composition comprising in combination a polycarbonate, a polycarbonate-polysiloxane copolymer, an impact modifier composition comprising ABS or BABS, a second impact modifier different from BABS or ABS, an aromatic vinyl copolymer, and optionally a gel-type low gloss additive, wherein the 60° gloss of the thermoplastic composition is measured to be less than or equal to 14 GU on 3 millimeter chips having a textured surface when measured according to ASTM D2457, and wherein a molded sample of the thermoplastic composition has a low temperature notched Izod impact at ?40° C. of at least 65 KJ/m2 when measured according to ISO 180/1A is disclosed. The composition has low gloss, high low temperature impact, and a significantly improved balance of properties.

Abstract: A thermoplastic composition comprising in combination a polycarbonate, an impact modifier composition comprising ABS or BABS, a second impact modifier different from BABS or ABS, an aromatic vinyl copolymer, and a gel-type low gloss additive, wherein the 60° gloss of the thermoplastic composition is measured to be less than or equal to 11.3 GU on 3 millimeter chips having a textured surface when measured according to ASTM D2457, and wherein a molded sample of the thermoplastic composition has a low temperature notched Izod impact at ?40° C. of at least 30 KJ/m2 when measured according to ISO 180/1A is disclosed. The composition has low gloss and a significantly improved balance of properties.

Abstract: An underfill composition is formulated to increase the surface tension thereof for use in capillary underfilling of an integrated circuit die that is coupled to a mounting substrate. A method includes mixing a surface tension-increasing additive with a bulk polymer and a hardener and allowing the underfill composition to flow between the integrated circuit die and the mounting substrate. An article is achieved by the method. The article can be assembled into a computing system.

Abstract: The invention relates to an aqueous coating composition which comprises a mixture of polyvinylpyrrolidone, a surfactant and optionally an adhesion-promoting polymer. This mixture is suitable for inline coating of biaxially oriented polyester films. The thus obtained films feature a characteristic hydrophilic surface which prevents the fogging of the films with water droplets.

Abstract: The present invention is directed to a peroxide curable rubber compound containing a butyl rubber polymer and an olefin polymer of ethylene and at least one ?-olefin. The present invention is also directed to a peroxide curable rubber compound containing a butyl polymer and an EP(D)M rubber polymer.

Abstract: A mixture of at least two thermoplastic particles having reactive grups which when melted and mixed react to form a high molecular weight polymer. The blend of particles when molten is particularly useful in forming double insulating glass or plastic panels.

Abstract: A thermoplastic molding composition comprising a graft polymer is disclosed. The graft polymer contains: a) a continuous phase containing the polymerized product of at least one vinylaromatic monomer and at least one ethylenically unsaturated nitrile monomer, and b) a disperse phase containing ethylene/?-olefin rubber that is grafted with the polymerization product of at least one vinylaromatic monomer and at least one ethylenically unsaturated nitrile monomer. The weight average molecular weight of the continuous phase is 130,000 to 275,000 g/mole and the disperse phase is characterized in that its, weight average particle size is less than 0.90 ?m. The molding composition is characterized in improved resistance to weathering.

Abstract: A plastic composition including polymeric nanoparticles having a diameter of 1 to 100 nanometers, and a polymeric component. Also provided is a method for providing such a plastic composition.

Abstract: Several compositions for use as structural adhesives are disclosed. The compositions include a monomer component and a catalyst component. In one aspect, the monomer component includes a first elastomeric material of a block copolymer of styrene and isoprene, a second elastomeric material of a block copolymer of styrene and butadiene, and a cross-linked rubber of a copolymer of acrylonitrile and butadiene. In a second aspect, the monomer component includes a first elastomeric material of a block copolymer of styrene and butadiene, and a cross-linked rubber of a copolymer of acrylonitrile and butadiene. In another aspect, isophthalic acid is utilized as a polymerizable acid monomer in combination with a phosphate ester. In another aspect, the monomer component includes a cohesive failure mode promoter of rosin esters or of talc.

Abstract: Thermoplastic resin compositions containing a rubber-reinforced thermoplastic resin (A) obtained by graft polymerizing a monomeric mixture (b) in the presence of a rubber-like polymer (a), and a copolymer (B) obtained by polymerizing an aromatic vinyl compound, a vinyl cyanide compound and optionally other copolymerizable monomeric compound(s), which copolymer (B) being a mixture of a copolymer (B1) having Mw of 50,000 to 110,000 and a copolymer (B2) having Mw of 115,000 to 400,000. The content of the rubber-like polymer (a) content in the rubber-reinforced thermoplastic resin (A) is 10 to 25% by weight, the vinyl cyanide monomeric unit in the acetone soluble matter is 15 to 40% by weight, and the ratios of Mw to Mn and MZ to Mn of the acetone soluble matter being 2 to 5 and 5 to 11, respectively.

Abstract: A rubber composition comprising a combination of a nitrile rubber and an epilhalohydrin rubber is cross-linked to give a crosslinked product, by using at least two kinds of crosslinking agents selected from a sulfur-containing crosslinking agent, a mercaptotriazine crosslinking agent and a 2,3-dimercaptoquinoxaline crosslinking agent.

Abstract: The invention provides a pseudo cross-link resin composition comprises at least tow polymer molecules; wherein the resin is obtained by mixing a vinylic polymer molecule A that has an atomic group capable of forming an intermolecular hydrogen bond in a molecular side chain and/or at a molecular tail end of the polymer molecule, and a vinylic polymer molecule B that has an atomic group capable of forming an intermolecular hydrogen bond in a molecular side chain and/or in a molecular skeleton of the polymer molecule; wherein the vinylic polymer molecule A is a polymer and/or copolymer that has a carboxyl group or a hydroxyl group in a molecular side chain and/or at a molecular tail end, and the vinylic polymer molecule B is a polymer and/or copolymer having at least one or more nitrogen atom in a molecular side chain and/or a molecular skeleton; wherein the vinylic polymer molecule A and the vinylic polymer molecule B are mixed together, the intermolecular hydrogen bond is formed therebetween, and adding a sili

Abstract: The present invention relates to nitrile rubber polymers having lower molecular weights and narrower molecular weight distributions than those known in the art. The present invention also relates to a process for the manufacture of said nitrile rubber and the use of said nitrile rubber for the manufacture of shaped articles.

Abstract: A process has now been discovered that permits the simultaneous crosslinking and derivation of an, optionally hydrogenated, polymer whose backbone is composed of a conjugated diene, an unsaturated nitrile and an unsaturated carboxylic acid in the presence of a coupling/condensing agent. This permits the preparation of a novel polymeric material that is an optionally hydrogenated polymer of a conjugated diene, an unsaturated nitrile and a derived unsaturated acid. It has also been found that this novel polymeric material has unexpected and valuable properties.

Abstract: The present invention relates to a high-frequency weldable thermoplastic rubber composition, to a method of rendering non-polar thermoplastic rubbers high-frequency weldable, to a high-frequency weldable shaped article obtainable from the composition according to the invention, to a method for manufacturing said shaped articles and to a method of high-frequency welding of said articles. Furthermore, the present invention relates to shaped high-frequency welded articles obtainable by the method according to the present invention.

Abstract: A pneumatic tire having a rubber component where the rubber in said component is comprised of (A) from 10 to 75 phr of a rubber gel selected from the group consisting of polybutadiene gel, styrene butadiene gel, acrylonitrile-butadiene gel, chloroprene gel, natural rubber gel, and mixtures thereof; (B) from 1 to 25 phr of syndiotactic 1,2-polybutadiene; and (C) a rubber containing olefinic unsaturation.

Abstract: A method for preparing a weatherable thermoplastic resin, having superior weatherability and colorability and a weatherable thermoplastic resin prepared by the method are provided. The method includes preparing a seed by adding a water-soluble initiator to either an aromatic vinyl compound or a (meth)acrylic acid alkyl ester to obtain a first compound and performing polymerization with respect to the first compound; preparing an alkyl acrylate rubber polymer by adding an alkyl acrylate monomer, a first emulsifier of pH about 3 to about 9, and an oil-soluble initiator to the seed to obtain a second compound and performing polymerization with respect to the second compound; and preparing graft copolymer by adding the aromatic vinyl compound, a vinyl cyanide compound, a second emulsifier of pH about 9 to about 13, and the oil-soluble initiator to the alkyl acrylate rubber polymer to obtain a third compound and performing graft copolymerization with respect to the third compound.

Abstract: A valve or pump gasket for sealing a fluid dispenser device comprising a valve or a pump mounted on a fluid container, said gasket being characterized in that it comprises one or more of the following elastomer materials: a) a hydrogenated nitrile butadiene rubber (HNBR); b) an octene-ethylene copolymer (OEC); and c) a butyl or a halobutyl rubber.

Abstract: A thermoplastic molding composition that features a combination of good notched impact strength and thermoplastic processability is disclosed. The composition contains one or more thermoplastic (co)polymers, a graft polymer and a combination of at least 3 components chosen from a compound (I) having at least one structural unit conforming to where M=a metal, and n=the valence of the metal M, and a compound (II) having at least one structural unit conforming to and a compound (III) having at least one structural unit conforming to and a compound (IV) that contains none of the structural units of (I), (II) and (III).

Abstract: Disclosed are a precursor composition, a rubber component and a shear ply prepared from the precursor composition, and methods for making and using the same. The precursor composition includes a first hydrogenated nitrile conjugated-diene copolymer modified by a metal salt unsaturated carboxylic acid ester, wherein the first hydrogenated nitrile conjugated-diene copolymer is derived from a first ethylenically unsaturated nitrile and a first conjugated diene a second hydrogenated nitrile conjugated-diene copolymer derived from a second ethylenically unsaturated nitrile and a second conjugated diene; and a curing agent.

Abstract: The present invention relates to activated biocompatible non-antigenic copolymers formed by copolymerizing polyethyleneimine with biocompatible polymer other than polyethyleneimine, biologically active non-antigenic conjugates formed by binding said copolymers to biologically active materials such as drugs or proteins. A biologically active non-antigenic conjugate of the present invention has a characteristic feature in that its constitutive copolymer essentially consists of hydrophilic polymer, which plays a role to provide high stability and long in vivo half-life of the hydrophobic drugs or proteins, and positively charged polymer which functions to increase the cellular uptake of the drugs or proteins.

Abstract: A rubber composition for a hose, which comprises a nitrile rubber (A) comprising 45-55 weight % of &agr;,&bgr;-ethylenically unsaturated nitrile monomer units and 55-45% by weight of conjugated diene monomer units, an epihalohydrin rubber (B), and a crosslinking agent (CA) for the nitrile rubber and/or a crosslinking agent (CB) for the epihalohydrin rubber; the amount of nitrile rubber (A) being 25-80 weight % based on the sum of nitrile rubber (A) and epihalohydrin rubber (B); and a hose having a layer comprised of a crosslinked product of the rubber composition. The hose has excellent resistance to fuel oil permeation and cold resistance, and therefore, it is especially suitable as fuel oil hoses of an automobile.

Abstract: The invention relates to a molding composition comprising, based on the total of components A to G, which is 100% by weight, a) as component A of the molding composition, from 1 to 99,59% by weight of at least one polycondensate, b) as component B, from 0.1 to 20% by weight of at least one particulate graft copolymer with a glass transition temperature of the soft phase below 0° C. and with a median particle size of from 50 to 1000 nm, c) as component C, from 0.1 to 20% by weight of at least one copolymer made from the following monomers c1) as component C1, from 50 to 90% by weight of at least one vinylaromatic monomer, and c2) as component C2, from 10 to 50% by weight of acrylonitrile and/or methacrylonitrile, in each case based on component C, d) as component D, from 0 to 20% by weight of a copolymer similar to component C, where the content in % by weight of acrylonitrile and/or methacrylonitrile in component C differs from that in component D, e) as component E, from 0.

Abstract: An additive mixture containing a dibenzoate and either or both of a compound containing at least one structural unit and a compound containing at least one structural unit is disclosed. The additive combination enhances the processability of a thermoplastic molding composition that contains a (co)polymer of styrene, methyl methacrylate, acrylonitrile, methacrylonitrile, maleic anhydride and N-substituted maleimide and a graft copolymer.

Abstract: A heterogeneous anion exchanger comprising from 35 to 85 mass % of an anion exchange resin and from 15 to 65 mass % of a binder polymer, wherein the anion exchange resin is made of a polymer having repeating units represented by the following formula (1): wherein R is a C3-8 alkylene group or an alkyleneoxyalkyl group having a total carbon number of from 4 to 9, R1 is a C1-4 alkyl group which may be substituted by a hydroxyl group, each of R2 and R3 is a C1-4 alkyl group, and X− is an anion, and wherein any hydrogen atom bonded to the benzene ring may be substituted by an alkyl group or a halogen atom.

Abstract: Adhesive composition, including a mixture of about 1 percent to about 35 percent by weight of chlorinated polymer, about 1 percent to about 35 percent by weight of a nitrile elastomer, a rubber-modified acrylonitrile copolymer, or mixtures thereof, and about 25 percent to about 90 percent by weight of an alkyl acrylate or methacrylate monomer.

Abstract: Extrusion processability of non-fluorinated melt-processable polymers is improved by introducing a process aid package comprising at least two unimodal fluoroelastomers having different Mooney viscosities.

Abstract: A method for continuously preparing a heat resistant &agr;-methylstyrene-acrylonitrile copolymer by bulk polymerization, comprising the steps of: a) Continuously charging a mixture of monomers including following materials into a continuous polymerization system with two or more stirred-vessel reactors connected in series: i) 60 to 75% (by weight of Yá-methylstyrene; ii) 25 to 40% by weight of acrylonitrile; iii) 5 to 15% by weight of a solvent; and iv) 0.05 to 0.3% by weight of a mixed initiator of an organic peroxide with a multifunctional group and an organic peroxide with a monofunctional group; b) Continuously polymerizing the monomer mixture charged at step a) starting from the first reactor to convert 50 to 70% by weight of total charged monomers into a polymer; and c) transferring reacted liquid containing the polymer from step b) to an evaporator, and then separating the polymer by evaporating unreacted monomers and solvents.

Abstract: Polymer composition comprising (A) (co)polymers based on chlorotrifluoroethylene (PCTFE) and (B) copolymers based on ethylene/chlorotrifluoroethylene (ECTFE) and/or ethylene/tetrafluoroethylene (ETFE).

Abstract: The invention provides for a process of making a compatibilized blend composition produced by mixing general purpose rubbers (GPR), selected from natural rubber, polyisoprene, polybutadiene, nitrile rubber, poly(styrene-co-butadiene) and poly(acrylonitrile-co-butadiene), a copolymer of isobutylene and methyl styrene, and a multifunctional agent. The compatibilized blend composition may also be cured.

Abstract: A process for producing a succinimide resin composition is provided which comprises reacting a maleic anhydride-olefin type copolymer constituted of 40-60 mol % of maleic anhydride units, 60-40 mol % of olefin units, and 0-20 mol % of a copolymerizable monomer units with one or more amine compounds for imide formation in the presence of a second polymer other than the succinimide resin. This process improves the productivity by lowering the torque in the extrusion reaction, giving a succinimide copolymer resin composition having low yellowness and high transparency with high production efficiency.

Abstract: A molded or formed product obtained by molding or forming a resin composition comprising (A) at least one vinyl cyclic hydrocarbon polymer selected from the group consisting of hydrogenated products of aromatic vinyl polymers, vinylcyclohexene polymers or hydrogenated products thereof, and vinylcyclohexane polymers, and (B) at least one substance selected from the group consisting of compounding additives incompatible with the polymer, organic compounds having at least one alcoholic hydroxyl group and at least one ether linkage, and organic compounds having at least one alcoholic hydroxyl group and at least one ester linkage, wherein the initial light transmittance (a) of the molded or formed product at an optional wavelength within a range of 400 to 800 nm and the light transmittance (b) of the molded or formed product after the molded or formed product is held for 1,000 hours in an atmosphere of 65° C.

Abstract: A molded or formed product obtained by molding or forming a resin composition comprising (A) at least one vinyl cyclic hydrocarbon polymer selected from the group consisting of hydrogenated products of aromatic vinyl polymers, vinylcyclohexene polymers or hydrogenated products thereof, and vinylcyclohexane polymers, and (B) at least one substance selected from the group consisting of compounding additives incompatible with the polymer, organic compounds having at least one alcoholic hydroxyl group and at least one ether linkage, and organic compounds having at least one alcoholic hydroxyl group and at least one ester linkage, wherein the initial light transmittance (a) of the molded or formed product at an optional wavelength within a range of 400 to 800 nm and the light transmittance (b) of the molded or formed product after the molded or formed product is held for 1,000 hours in an atmosphere of 65° C.

Abstract: An objective of the present invention is to provide an unsaturated nitrile-conjugated diene-typed rubber capable of giving a vulcanized rubber which exhibits is well-balanced in terms of the mechanical strength, the oil resistance and the like, as well as a process for the production of the same, and a rubber composition which is containing such rubber and exhibits an excellent processability as well as a process for the production of the same. The unsaturated nitrile-conjugated diene-typed rubber in the invention is produced by polymerizing using certain amounts of an olefinically unsaturated nitrile monomer such as acrylonitrile and a conjugated diene monomer such as butadiene at first, and continuing by supplying a remainder of the monomers at a certain ratio continuously or stepwise to proceed the polymerization.