Abstract: A carboxyl group-containing nitrile rubber having an iodine value of 120 or less, wherein the content of sodium is 1500 ppm by weight or less, the total content of calcium, magnesium, and aluminum is 350 ppm by weight or less, and the storage elastic modulus at 140° C. is 350 kPa or more.

Abstract: A method of recovering nitrile rubber from water-containing crumbs includes crumb-like nitrile rubber using an extruder in which a screw is disposed inside a barrel so as to be capable of being rotationally driven. The barrel is formed with at least a washing zone. The method includes supplying washing water to the washing zone at a water pressure of 0.2 MPa or higher while mixing the crumb-like nitrile rubber and the supplied washing water in the washing zone, thereby washing the crumb-like nitrile rubber.

Abstract: A latex including: a nitrile rubber containing an ?,?-ethylenically unsaturated nitrile monomer unit in a content of 8 to 50 wt % and an ?,?-ethylenically unsaturated dicarboxylic acid monoester monomer unit in a content of 1 to 10 wt %, and having an iodine value of 120 g/100 g or less; and a benzisothiazoline-based compound represented by the following general formula (1), wherein the content of the benzisothiazoline-based compound is 50 ppm by weight or more, with respect to the nitrile rubber, and a redox potential of the latex is 80 to 800 mV. In the general formula (1) mentioned above, R1 represents a hydrogen atom, or a substituted or unsubstituted organic group, R2 each independently represents a hydrogen atom, or a substituted or unsubstituted organic group, and “n” represents an integer of 0 to 4.

Abstract: A method for producing a hydrogenated conjugated diene polymer latex includes: a hydrogenation step of dissolving or dispersing a hydrogenation catalyst containing a platinum group element in a latex of a conjugated diene polymer to hydrogenate a carbon-carbon unsaturated bond in the polymer; an insoluble complex formation step of complexing the platinum group element with a complexing agent to form an insoluble complex; and an insoluble complex removing step of continuously feeding the latex which has undergone the insoluble complex formation step to a centrifuge machine and continuously performing a centrifugation operation to continuously remove the insoluble complex from the latex and continuously discharge the insoluble complex out of the centrifuge machine. In the insoluble complex removal step the feed rate of the latex to the centrifuge machine is adjusted to 0.5 to 15 m3/hour, and the centrifugal force in the centrifugation operation is adjusted to 200 to 10,000 G.

Abstract: A latex including: a nitrile rubber containing an ?,?-ethylenically unsaturated nitrile monomer unit in a content of 8 to 50 wt % and an ?,?-ethylenically unsaturated dicarboxylic acid monoester monomer unit in a content of 1 to 10 wt %, and having an iodine value of 120 g/100 g or less; and a benzisothiazoline-based compound represented by the following general formula (1), wherein the content of the benzisothiazoline-based compound is 50 ppm by weight or more, with respect to the nitrile rubber, and a redox potential of the latex is 80 to 800 mV. In the general formula (1) mentioned above, R1 represents a hydrogen atom, or a substituted or unsubstituted organic group, R2 each independently represents a hydrogen atom, or a substituted or unsubstituted organic group, and “n” represents an integer of 0 to 4.

Abstract: A method for producing a hydrogenated conjugated diene polymer latex includes: a hydrogenation step of dissolving or dispersing a hydrogenation catalyst containing a platinum group element in a latex of a conjugated diene polymer to hydrogenate a carbon-carbon unsaturated bond in the polymer; an insoluble complex formation step of complexing the platinum group element with a complexing agent to form an insoluble complex; and an insoluble complex removing step of continuously feeding the latex which has undergone the insoluble complex formation step to a centrifuge machine and continuously performing a centrifugation operation to continuously remove the insoluble complex from the latex and continuously discharge the insoluble complex out of the centrifuge machine. In the insoluble complex removal step the feed rate of the latex to the centrifuge machine is adjusted to 0.5 to 15 m3/hour, and the centrifugal force in the centrifugation operation is adjusted to 200 to 10,000 G.