To provide a statistical copolymer containing a chloroprene monomer unit and an unsaturated nitrile monomer unit which has a satisfactory oil resistance. A method for producing a statistical copolymer containing a chloroprene monomer unit and an unsaturated nitrile monomer unit includes a step for conducting continuous addition or 10 cycles or more of intermittent portionwise addition of the chloroprene monomer after initiation of a polymerization reaction is provided. A rubber composition using a statistical copolymer according to the invention or a vulcanized molded article containing the rubber composition is excellent in terms of oil resistance, mechanical strength, compression set at a low temperature and flex fatigue resistance.

To provide a statistical copolymer containing a chloroprene monomer unit and an unsaturated nitrile monomer unit which has a satisfactory oil resistance. A method for producing a statistical copolymer containing a chloroprene monomer unit and an unsaturated nitrile monomer unit includes a step for conducting continuous addition or 10 cycles or more of intermittent portionwise addition of the chloroprene monomer after initiation of a polymerization reaction is provided. A rubber composition using a statistical copolymer according to the invention or a vulcanized molded article containing the rubber composition is excellent in terms of oil resistance, mechanical strength, compression set at a low temperature and flex fatigue resistance.

According to an exemplary embodiment of the present invention, provided is a latex composition for dip molding, which includes a copolymer latex formed by polymerizing an isoprene monomer, an ethylenically unsaturated nitrile monomer, and an ethylenically unsaturated acid monomer, wherein a dip-molded article made of the latex composition for dip molding exhibits a durability test result of 45 minutes or more.

According to an exemplary embodiment of the present invention, provided is a latex composition for dip molding, which includes a copolymer latex formed by polymerizing an isoprene monomer, an ethylenically unsaturated nitrile monomer, and an ethylenically unsaturated acid monomer, wherein a dip-molded article made of the latex composition for dip molding exhibits a durability test result of 45 minutes or more.

According to an exemplary embodiment of the present invention, provided is a latex composition for dip molding, which includes a copolymer latex formed by polymerizing an isoprene monomer, an ethylenically unsaturated nitrile monomer, and an ethylenically unsaturated acid monomer, wherein a dip-molded article made of the latex composition for dip molding exhibits a durability test result of 45 minutes or more.

A method for producing a nitrile group-containing copolymer rubber including copolymerizing a monomer mixture containing an α,β-ethylenically unsaturated nitrile monomer and a conjugated diene monomer, in which the copolymer has a Mooney viscosity (ML1+4, 100° C.) in a range of 30 to 60 at a time point when a polymerization conversion rate is 60%, the copolymerization is carried out until the polymerization conversion rate reaches 85% or more, and the obtained nitrile group-containing copolymer rubber has a Mooney viscosity (ML1+4, 100° C.) of 85 to 150.

A nitrile-group-containing copolymer rubber, including 15% by weight or more and less than 28% by weight of α,β-ethylenically unsaturated nitrile monomer units (a), 10 to 50% by weight of α,β-ethylenically unsaturated monocarboxylic acid ester monomer units (b), 22 to 74% by weight of conjugated diene monomer units (c), and 1 to 10% by weight of carboxyl group-containing monomer units (d) and having an iodine value of 120 or less, wherein the conjugated diene monomer units (c) are at least partially hydrogenated, and the proportion of isoprene units in the conjugated diene monomer units (c) is 5% by weight or more and less than 33% by weight.

A nitrile-group-containing copolymer rubber, including 15% by weight or more and less than 28% by weight of α,β-ethylenically unsaturated nitrile monomer units (a), 10 to 50% by weight of α,β-ethylenically unsaturated monocarboxylic acid ester monomer units (b), 22 to 74% by weight of conjugated diene monomer units (c), and 1 to 10% by weight of carboxyl group-containing monomer units (d) and having an iodine value of 120 or less, wherein the conjugated diene monomer units (c) are at least partially hydrogenated, and the proportion of isoprene units in the conjugated diene monomer units (c) is 5% by weight or more and less than 33% by weight.

A pre-dispersant composition includes a hydrogenated nitrile-butadiene rubber and an amide-based dispersion medium, wherein viscosity is in a range of 70 cPs to 3,000 cPs when measured with a Brookfield viscometer at 25° C., and a moisture content is 0.9 wt % or less. An electrode slurry composition including the pre-dispersant composition, and an electrode for a secondary battery and a secondary battery which are prepared by using the electrode slurry composition are also provided.

Provided is a method for preparing a latex composition for dip forming, the method including: (a) preparing a monomer mixture including a conjugated diene-based monomer, an ethylenically unsaturated nitrile monomer and an ethylenically unsaturated acid monomer; (b) introducing starch, an emulsifier and an inorganic solvent into the monomer mixture; and (c) preparing a copolymer latex by introducing a polymerization initiator, wherein the copolymer includes the starch in a main chain thereof.