A nitrile group-containing copolymer rubber including 10 to 60 wt % of an α,β-ethylenically unsaturated nitrile monomer unit a nd 1 to 60 wt % of an α,β-ethylenically unsaturated dicarboxylic a cid monoester monomer unit, and having an iodine value of 120 or 1 ess, wherein a processability index Ipro (Ipro=CC×SA) is 0.003 0 or less, where the processability index Ipro is the product of the carboxyl group content CC, which is the number of moles of carboxyl groups per 100 g of nitrile group-containing copolymer rubber, and the absorbance area SA of a carboxylic anhydride group determined by infrared spectroscopy.

A masterbatch manufacturing method in accordance with the present disclosure comprises an operation in which pre-coagulation rubber latex comprising filler is coagulated to obtain a coagulum; an operation in which the coagulum is dewatered; and an operation in which the dewatered coagulum is plasticized as it is dried by means of an extruder; wherein, during the operation in which the dewatered coagulum is plasticized as it is dried, the coagulum comprises a peptizing agent.

An extruder is disclosed including: a barrel; and a screw provided with a helical groove; wherein the screw comprises a dewatering portion comprising a first portion, and a second portion at a location downstream from the first portion; wherein, at the dewatering portion, clearance between the groove and the barrel decreases as one proceeds downstream; and wherein clearance reduction ratio at the first portion is greater than clearance reduction ratio at the second portion.

An extruder is disclosed including: a barrel; and a screw provided with a helical groove; wherein the screw comprises a dewatering portion comprising a first portion, and a second portion at a location downstream from the first portion; wherein, at the dewatering portion, clearance between the groove and the barrel decreases as one proceeds downstream; and wherein clearance reduction ratio at the first portion is greater than clearance reduction ratio at the second portion.

Systems and methods for extracting useful by-products and natural rubber from non-Hevea rubber bearing plants are disclosed.

Systems and methods for extracting useful by-products and natural rubber from non-Hevea rubber bearing plants are disclosed.

A resin composition is produced by a method including a step of rapidly freezing a latex containing fine polymer particles (A), a step of thawing the latex which has been frozen in the preceding step, a step of mixing, into the latex which has been subjected to the preceding step, a resin (B) having a specific viscosity, and after the preceding steps, a step of separating the latex into a resin composition and a water component. The resin composition is an agglutinate containing the fine polymer particles (A) and the resin (B).

A resin composition is produced by a method including a step of rapidly freezing a latex containing fine polymer particles (A), a step of thawing the latex which has been frozen in the preceding step, a step of mixing, into the latex which has been subjected to the preceding step, a resin (B) having a specific viscosity, and after the preceding steps, a step of separating the latex into a resin composition and a water component. The resin composition is an agglutinate containing the fine polymer particles (A) and the resin (B).

Systems and methods for extracting useful by-products and natural rubber from non-Hevea rubber bearing plants are disclosed.

Systems and methods for extracting useful by-products and natural rubber from non-Hevea rubber bearing plants are disclosed.