Disclosed is a block copolymer including one or more blocks of an acrylate polymer and one or more blocks of a chloroprene polymer, wherein the number average molecular weight of the block copolymer is 110,000 or more, the number average molecular weight of the block of a chloroprene polymer is 80,000 or more in total, and the block copolymer has a functional group with a structure represented by the following chemical formula (1) or (2): ##STR00001##
wherein in the chemical formula (1), R.sup.1 represents hydrogen, chlorine, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group or a substituted, or unsubstituted heterocyclyl group.

A method for producing a chloroprene-based polymer latex which can efficiently remove a residual volatile organic substance from the chloroprene-based polymer latex while suppressing the deposition of agglomerates is provided. In the method for producing a chloroprene-based polymer latex of the present invention, when the residual volatile organic substance comprised in the latex is volatilized and removed, a mixed fluid of one or more gases selected from the group consisting of inert gases and air, and water is contacted with the latex at a gas pressure higher than the saturated water vapor pressure, and a temperature of the mixed fluid is a temperature lower than a boiling point of water at the gas pressure.

A method for producing a chloroprene-based polymer latex which can efficiently remove a residual volatile organic substance from the chloroprene-based polymer latex while suppressing the deposition of agglomerates is provided. In the method for producing a chloroprene-based polymer latex of the present invention, when the residual volatile organic substance comprised in the latex is volatilized and removed, a mixed fluid of one or more gases selected from the group consisting of inert gases and air, and water is contacted with the latex at a gas pressure higher than the saturated water vapor pressure, and a temperature of the mixed fluid is a temperature lower than a boiling point of water at the gas pressure.

The present invention pertains to a frictional power transmission belt including a tension member extending in the longitudinal direction of the belt and an adhesion rubber layer in contact with at least a portion of the tension member, in which the adhesion rubber layer is formed of a vulcanized rubber composition containing a rubber component, short fibers having an average fiber diameter of 2 μm or more, and a filler.

Essentially ethylene thiourea free cross linkable composition comprising a chloroprene rubber having defined contents of cations from the second or third main group and resinate anions are provided, which possess improved curing characteristics for increased productivity and lower vulcanization temperatures for energy-saving manufacturing methods and vulcanizates obtained by using said chloroprene rubber.

Essentially ethylene thiourea free cross linkable composition comprising a chloroprene rubber having defined contents of cations from the second or third main group and resinate anions are provided, which possess improved curing characteristics for increased productivity and lower vulcanization temperatures for energy-saving manufacturing methods and vulcanizates obtained by using said chloroprene rubber.

A method for manufacturing a chloroprene polymer composition, the method including: a polymerization step of polymerizing chloroprene in the presence of at least one rosin acid component selected from the group consisting of a rosin acid and a rosin acid salt to obtain a chloroprene polymer composition containing a chloroprene polymer, in which in the rosin acid component, a mass ratio B1/A1 of a total amount B1 of abietic acid, neoabietic acid, palustric acid, levopimaric acid, and salts thereof with respect to a total amount A1 of dehydroabietic acid, pimaric acid, isopimaric acid, dihydroabietic acid, and salts thereof is 0.10 to 3.00, and a toluene insoluble content of the chloroprene polymer is 50% by mass or more.

A method for manufacturing a chloroprene polymer composition, the method including: a polymerization step of polymerizing chloroprene in the presence of at least one rosin acid component selected from the group consisting of a rosin acid and a rosin acid salt to obtain a chloroprene polymer composition containing a chloroprene polymer, in which in the rosin acid component, a mass ratio B1/A1 of a total amount B1 of abietic acid, neoabietic acid, palustric acid, levopimaric acid, and salts thereof with respect to a total amount A1 of dehydroabietic acid, pimaric acid, isopimaric acid, dihydroabietic acid, and salts thereof is 0.10 to 3.00, and a toluene insoluble content of the chloroprene polymer is 50% by mass or more.

Provide is a polymer having a narrow molecular weight distribution by living radical polymerization.

A polymer manufacturing method comprising a step of performing living radical polymerization using 0.005 to 0.5 parts by mass of an oxygen radical scavenger per 100 parts by mass of a radical polymerizable monomer.

Provide is a polymer having a narrow molecular weight distribution by living radical polymerization.

A polymer manufacturing method comprising a step of performing living radical polymerization using 0.005 to 0.5 parts by mass of an oxygen radical scavenger per 100 parts by mass of a radical polymerizable monomer.