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.

A glove including a cured film of an elastomer containing a (meth)acrylonitrile-derived structural unit, an unsaturated carboxylic acid-derived structural unit and a butadiene-derived structural unit in a polymer main chain, wherein the elastomer contains 20 to 40% by weight of a (meth)acrylonitrile-derived structural unit, 1 to 10% by weight of an unsaturated carboxylic acid-derived structural unit and 50 to 75% by weight of a butadiene-derived structural unit, and has a crosslinked structure of a carboxyl group in the unsaturated carboxylic acid-derived structural unit with an epoxy crosslinker containing an epoxy compound having three or more epoxy groups in one molecule.

A glove including a cured film of an elastomer containing a (meth)acrylonitrile-derived structural unit, an unsaturated carboxylic acid-derived structural unit and a butadiene-derived structural unit in a polymer main chain, wherein the elastomer contains 20 to 40% by weight of a (meth)acrylonitrile-derived structural unit, 1 to 10% by weight of an unsaturated carboxylic acid-derived structural unit and 50 to 75% by weight of a butadiene-derived structural unit, and has a crosslinked structure of a carboxyl group in the unsaturated carboxylic acid-derived structural unit with an epoxy crosslinker containing an epoxy compound having three or more epoxy groups in one molecule.

A crosslinkable rubber composition includes a carboxyl group-containing nitrile rubber (A); a carboxyl group-containing acrylic rubber (B); and a polyamine-based crosslinking agent (C), where a ratio of a weight of the carboxyl group-containing nitrile rubber (A) to a weight of the carboxyl group-containing acrylic rubber (B) is from 5:95 to 95:5. The carboxyl group-containing nitrile rubber (A) includes 5 to 60% by weight of α,β-ethylenically unsaturated nitrile monomer units, and α,β-ethylenically unsaturated monocarboxylic acid ester monomer units. The carboxyl group-containing nitrile rubber (A) has an iodine value of 120 or less.

A crosslinkable rubber composition includes a carboxyl group-containing nitrile rubber (A); a carboxyl group-containing acrylic rubber (B); and a polyamine-based crosslinking agent (C), where a ratio of a weight of the carboxyl group-containing nitrile rubber (A) to a weight of the carboxyl group-containing acrylic rubber (B) is from 5:95 to 95:5. The carboxyl group-containing nitrile rubber (A) includes 5 to 60% by weight of α,β-ethylenically unsaturated nitrile monomer units, and α,β-ethylenically unsaturated monocarboxylic acid ester monomer units. The carboxyl group-containing nitrile rubber (A) has an iodine value of 120 or less.

A latex composition includes a latex of a conjugated diene polymer (A) having a glass transition temperature of 10° C. or less and a latex of a polymer (B) having a glass transition temperature of more than 10° C., wherein the value of (CS(B)−CS(A)) is more than 0% by weight, where a chemical stability of the latex of the conjugated diene polymer (A) to CaCl.sub.2, when the solids concentration of the latex is 20% by weight, is defined as CS(A) (% by weight), and a chemical stability of the latex of the polymer (B) to CaCl.sub.2, when the solids concentration of the latex is 20% by weight, is defined as CS(B) (% by weight).

A latex composition includes a latex of a conjugated diene polymer (A) having a glass transition temperature of 10° C. or less and a latex of a polymer (B) having a glass transition temperature of more than 10° C., wherein the value of (CS(B)−CS(A)) is more than 0% by weight, where a chemical stability of the latex of the conjugated diene polymer (A) to CaCl.sub.2, when the solids concentration of the latex is 20% by weight, is defined as CS(A) (% by weight), and a chemical stability of the latex of the polymer (B) to CaCl.sub.2, when the solids concentration of the latex is 20% by weight, is defined as CS(B) (% by weight).

A method for producing a nitrile rubber, includes recovering a nitrile rubber from a latex of nitrile rubber by continuously feeding the latex of nitrile rubber and a coagulant into an extruder including a screw disposed inside a barrel to be rotatably driven, wherein the latex of nitrile rubber fed into the extruder contains 0.1 to 3 parts by weight of a hindered phenol-based antiaging agent having a molecular weight of 300 to 3000 relative to 100 parts by weight of the nitrile rubber.

A method for producing a nitrile rubber, includes recovering a nitrile rubber from a latex of nitrile rubber by continuously feeding the latex of nitrile rubber and a coagulant into an extruder including a screw disposed inside a barrel to be rotatably driven, wherein the latex of nitrile rubber fed into the extruder contains 0.1 to 3 parts by weight of a hindered phenol-based antiaging agent having a molecular weight of 300 to 3000 relative to 100 parts by weight of the nitrile rubber.

A polymer latex is described for the preparation of an elastomeric film obtained by free-radical emulsion polymerization of a mixture of ethylenically unsaturated monomers comprising: a) 15 to 99 wt.-% of conjugated dienes; b) 0 to 80 wt.-% of ethylenically unsaturated nitrile compounds; c) 0 to 70 wt.-% of vinyl aromatic monomers; the sum of ethylenically unsaturated nitrile compounds b) and vinyl aromatic monomers c) being 0.95 to 84.95 wt.-% d) 0.05 to 10 wt.-% of ethylenically unsaturated acids wherein the ethylenically unsaturated acids comprise d1) an ethylenically unsaturated acid comprising an acid functional group; and a spacer group separating the ethylenically unsaturated group and the acid functional group by at least 4 atoms; and e) 0 to 65 wt.-% of co-polymerizable ethylenically unsaturated compounds,
wherein monomers a) to e) are as defined.