A chloroprene copolymer latex containing a chloroprene copolymer having a structural unit derived from chloroprene and a structural unit derived from 2,3-dichloro-1,3-butadiene, in which a toluene insoluble content in the chloroprene copolymer is 50 to 95% by mass, and a modulus at 500% elongation of a film, which is obtained on a base material by dipping the base material in the chloroprene copolymer latex and then performing vulcanization at 100° C. for 30 minutes, according to JIS K 6251 is 4.0 MPa or less.

Provided is a method for producing purified chloroprene-based-polymer latex which enables efficiently removing a residual volatile organic substance from chloroprene-based-polymer latex while suppressing foaming and the deposition of aggregates. The method for producing purified chloroprene-based-polymer latex of the present invention has at least the following steps (I) to (III):

Step (I): a step of introducing chloroprene-based-polymer latex into a container beforehand,
Step (II): a step of removing a residual volatile organic substance in the chloroprene-based-polymer latex which satisfies specific requirements (1) to (4), and
Step (III): a step of collecting the latex from the container after performing the step (II) at least once, to thereby obtain purified chloroprene-based-polymer latex.

Provided is a method for producing purified chloroprene-based-polymer latex which enables efficiently removing a residual volatile organic substance from chloroprene-based-polymer latex while suppressing foaming and the deposition of aggregates. The method for producing purified chloroprene-based-polymer latex of the present invention has at least the following steps (I) to (III):

Step (I): a step of introducing chloroprene-based-polymer latex into a container beforehand,
Step (II): a step of removing a residual volatile organic substance in the chloroprene-based-polymer latex which satisfies specific requirements (1) to (4), and
Step (III): a step of collecting the latex from the container after performing the step (II) at least once, to thereby obtain purified chloroprene-based-polymer latex.

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.

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.

One embodiment of the present invention relates to a chloroprene copolymer latex, a method for producing a chloroprene copolymer latex, a chloroprene copolymer latex composition, and a molded article or dipped product of a chloroprene copolymer rubber. The chloroprene copolymer latex is a latex of a chloroprene copolymer including monomer units derived from 2-chloro-1,3-butadiene (chloroprene) and monomer units derived from 2-methyl-1,3-butadiene, wherein the tetrahydrofuran insoluble content in the chloroprene copolymer is 20% by mass or less, and the proportion of the monomer units derived from 2-methyl-1,3-butadiene is 10 to 27 mol % in the chloroprene copolymer.

One embodiment of the present invention relates to a chloroprene copolymer latex, a method for producing a chloroprene copolymer latex, a chloroprene copolymer latex composition, and a molded article or dipped product of a chloroprene copolymer rubber. The chloroprene copolymer latex is a latex of a chloroprene copolymer including monomer units derived from 2-chloro-1,3-butadiene (chloroprene) and monomer units derived from 2-methyl-1,3-butadiene, wherein the tetrahydrofuran insoluble content in the chloroprene copolymer is 20% by mass or less, and the proportion of the monomer units derived from 2-methyl-1,3-butadiene is 10 to 27 mol % in the chloroprene copolymer.

A chloroprene-unsaturated nitrile copolymer having 3 to 20% by mass of a structural unit derived from an unsaturated nitrile monomer, in which the chloroprene-unsaturated nitrile copolymer has a peak at 5.80 to 6.00 ppm in a 1H-NMR spectrum as measured in a deuterochloroform solvent, and a ratio (A/B) of a peak area (A) at 5.80 to 6.00 ppm and a peak area (B) at 4.05 to 6.20 ppm is 0.6/100 to 1.1/100.

A chloroprene-unsaturated nitrile copolymer having 3 to 20% by mass of a structural unit derived from an unsaturated nitrile monomer, in which the chloroprene-unsaturated nitrile copolymer has a peak at 5.80 to 6.00 ppm in a 1H-NMR spectrum as measured in a deuterochloroform solvent, and a ratio (A/B) of a peak area (A) at 5.80 to 6.00 ppm and a peak area (B) at 4.05 to 6.20 ppm is 0.6/100 to 1.1/100.

To provide a block copolymer that includes an aromatic vinyl compound polymer and a chloroprene polymer, has a number average molecular weight of 100,000 or more, is preferred for a rubber composition and an adhesive composition, and is suitable for industrial production. A block copolymer includes at least one aromatic vinyl compound polymer block and at least one chloroprene polymer block, has a functional group with a structure represented by Chemical Formula (1) or (2), and has a number average molecular weight of 100,000 or more. The chloroprene polymer block has a number average molecular weight of 80,000 or more in total. ##STR00001##
(In Chemical Formula (1), R.sup.1 is 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.)