A power transmission belt includes a belt body at least portion of which is made of a rubber composition containing a rubber component, cellulose-based fine fibers, and cotton powder.

A power transmission belt includes a belt body at least portion of which is made of a rubber composition containing a rubber component, cellulose-based fine fibers, and cotton powder.

An isoprene-based polymer latex composition includes a chloroprene polymer latex (A) and an isoprene polymer latex (B), in which the chloroprene polymer has a z-average particle size of 180 nm or greater and smaller than 300 nm, and a tetrahydrofuran-insoluble fraction of 80 to 99% by mass; the chloroprene polymer latex (A) is (1) a copolymer latex of chloroprene (A-1) and 2,3-dichloro-1,3-butadiene (A-2-1), or (2) a copolymer latex of the above (A-1) and (A-2-1), and another monomer (A-2-2); and the copolymer is obtained by copolymerization in which the ratio of 2,3-dichloro-1,3-butadiene (A-2-1) is 5.0 to 30.0% by mass relative to the total amount of the monomer components chloroprene (A-1) and 2,3-dichloro-1,3-butadiene (A-2-1) of 100% by mass. The isoprene-based polymer latex composition's quality is maintained, and the properties after cross-linking of a molded product obtained by dipping a dipping former into the composition multiple times do not deteriorate.

An isoprene-based polymer latex composition includes a chloroprene polymer latex (A) and an isoprene polymer latex (B), in which the chloroprene polymer has a z-average particle size of 180 nm or greater and smaller than 300 nm, and a tetrahydrofuran-insoluble fraction of 80 to 99% by mass; the chloroprene polymer latex (A) is (1) a copolymer latex of chloroprene (A-1) and 2,3-dichloro-1,3-butadiene (A-2-1), or (2) a copolymer latex of the above (A-1) and (A-2-1), and another monomer (A-2-2); and the copolymer is obtained by copolymerization in which the ratio of 2,3-dichloro-1,3-butadiene (A-2-1) is 5.0 to 30.0% by mass relative to the total amount of the monomer components chloroprene (A-1) and 2,3-dichloro-1,3-butadiene (A-2-1) of 100% by mass. The isoprene-based polymer latex composition's quality is maintained, and the properties after cross-linking of a molded product obtained by dipping a dipping former into the composition multiple times do not deteriorate.

An isoprene-based polymer latex composition includes a chloroprene polymer latex (A) and an isoprene polymer latex (B), in which the chloroprene polymer has a z-average particle size of 180 nm or greater and smaller than 300 nm, and a tetrahydrofuran-insoluble fraction of 80 to 99% by mass; the chloroprene polymer latex (A) is (1) a copolymer latex of chloroprene (A-1) and 2,3-dichloro-1,3-butadiene (A-2-1), or (2) a copolymer latex of the above (A-1) and (A-2-1), and another monomer (A-2-2); and the copolymer is obtained by copolymerization in which the ratio of 2,3-dichloro-1,3-butadiene (A-2-1) is 5.0 to 30.0% by mass relative to the total amount of the monomer components chloroprene (A-1) and 2,3-dichloro-1,3-butadiene (A-2-1) of 100% by mass. The isoprene-based polymer latex composition's quality is maintained, and the properties after cross-linking of a molded product obtained by dipping a dipping former into the composition multiple times do not deteriorate.

A method for producing a chloroprene graft copolymer latex includes a step of adding an ethylenic double bond-containing silane coupling agent (B) to a chloroprene polymer latex and graft copolymerizing the ethylenic double bond-containing silane coupling agent (B) to the chloroprene polymer (A) in the chloroprene polymer latex at 10° C. to 50° C. (inclusive). The amount of the ethylenic double bond-containing silane coupling agent (B) added is 0.4 parts by mass to 9.0 parts by mass (inclusive) per 100 parts by mass of the chloroprene polymer (A). The present invention also relates to an adhesive containing the chloroprene graft copolymer latex and to a method for using the adhesive. The present invention can provide a method for producing a chloroprene graft copolymer latex containing no organic solvent and having high adhesive strength to glass, an adhesive containing the same, and a method for using the adhesive.

A method for producing a chloroprene graft copolymer latex includes a step of adding an ethylenic double bond-containing silane coupling agent (B) to a chloroprene polymer latex and graft copolymerizing the ethylenic double bond-containing silane coupling agent (B) to the chloroprene polymer (A) in the chloroprene polymer latex at 10° C. to 50° C. (inclusive). The amount of the ethylenic double bond-containing silane coupling agent (B) added is 0.4 parts by mass to 9.0 parts by mass (inclusive) per 100 parts by mass of the chloroprene polymer (A). The present invention also relates to an adhesive containing the chloroprene graft copolymer latex and to a method for using the adhesive. The present invention can provide a method for producing a chloroprene graft copolymer latex containing no organic solvent and having high adhesive strength to glass, an adhesive containing the same, and a method for using the adhesive.

To provide a polychloroprene latex from which a dip-formed film that is excellent in mechanical properties while having flexibility can be obtained. The polychloroprene latex is a mercaptan-modified polychloroprene latex comprising polychloroprene that is a copolymer of chloroprene and 2,3-dichloro-1,3-butadiene, wherein in a solid state 13C NMR spectrum of the polychloroprene obtained by freeze-drying the mercaptan-modified polychloroprene latex, an area (A) of a peak at 126.2 to 127.6 ppm, an area (B) of a peak at 122.0 to 126.2 ppm and an area (C) of a peak at 129.9 to 130.3 ppm are in the ranges represented by the following expression (I), an amount of the 2,3-dichloro-1,3-butadiene copolymerized is 4 to 35% by mass per 100% by mass in total of the chloroprene and the 2,3-dichloro-1,3-butadiene contained in the polychloroprene, and a toluene-insoluble content of the polychloroprene is 50 to 100% by mass in 100% by mass of the polychloroprene.

[00001]$\begin{array}{cc}\frac{4.0}{100}\leqq \frac{A}{B-C}\leqq \frac{5.8}{100}& \left(I\right)\end{array}$

A rubber composition from which a vulcanized rubber simultaneously improved in three characteristics of oil resistance, cold resistance and ozone resistance can be obtained, and a molded article using the vulcanized rubber are provided. The rubber composition contains 50 to 99 parts by mass of a chloroprene rubber containing 0.01 to 20% by mass of an unsaturated nitrile monomer unit and 1 to 50 parts by mass of a non-conjugated diene rubber.

A rubber composition from which a vulcanized rubber simultaneously improved in three characteristics of oil resistance, cold resistance and ozone resistance can be obtained, and a molded article using the vulcanized rubber are provided. The rubber composition contains 50 to 99 parts by mass of a chloroprene rubber containing 0.01 to 20% by mass of an unsaturated nitrile monomer unit and 1 to 50 parts by mass of a non-conjugated diene rubber.