A catalytic system based at least on a preformation monomer selected from the group consisting of 1,3-dienes, ethylene, α-olefins and their mixtures, on a metallocene of formula {P(Cp)(Flu)LnG} and on an organometallic compound as cocatalyst is provided. In the formula, Ln denotes a metal atom which is a rare earth metal, G denotes a group comprising the borohydride BH.sub.4 unit or denotes a halogen atom X selected from the group consisting of chlorine, fluorine, bromine and iodine, Cp denotes a cyclopentadienyl group of formula C.sub.5H.sub.4, Flu denotes a fluorenyl group of formula C.sub.13H.sub.8, P being a group bridging the two Cp and Flu groups and comprising a silicon or carbon atom. Such a catalytic system exhibits an improved stability of the catalytic activity over time, in particular on storage.

A catalytic system based at least on a preformation monomer selected from the group consisting of 1,3-dienes, ethylene, α-olefins and their mixtures, on a metallocene of formula {P(Cp)(Flu)LnG} and on an organometallic compound as cocatalyst is provided. In the formula, Ln denotes a metal atom which is a rare earth metal, G denotes a group comprising the borohydride BH.sub.4 unit or denotes a halogen atom X selected from the group consisting of chlorine, fluorine, bromine and iodine, Cp denotes a cyclopentadienyl group of formula C.sub.5H.sub.4, Flu denotes a fluorenyl group of formula C.sub.13H.sub.8, P being a group bridging the two Cp and Flu groups and comprising a silicon or carbon atom. Such a catalytic system exhibits an improved stability of the catalytic activity over time, in particular on storage.

A catalytic system based at least on a preformation monomer selected from the group consisting of 1,3-dienes, ethylene, α-olefins and their mixtures, on a metallocene of formula {P(Cp)(Flu)LnG} and on an organometallic compound as cocatalyst is provided. In the formula, Ln denotes a metal atom which is a rare earth metal, G denotes a group comprising the borohydride BH.sub.4 unit or denotes a halogen atom X selected from the group consisting of chlorine, fluorine, bromine and iodine, Cp denotes a cyclopentadienyl group of formula C.sub.5H.sub.4, Flu denotes a fluorenyl group of formula C.sub.13H.sub.8, P being a group bridging the two Cp and Flu groups and comprising a silicon or carbon atom. Such a catalytic system exhibits an improved stability of the catalytic activity over time, in particular on storage.

Provided is a hydrogenated block copolymer, which is a hydrogenation product of a block copolymer including a polymer block (A) containing more than 70 mol % of a structural unit derived from an aromatic vinyl compound and a polymer block (B) containing 30 mol % or more of a structural unit derived from at least one selected from the group consisting of a conjugated diene compound and isobutylene, the hydrogenated block copolymer being satisfied with the following requirements (1) and (2):

Requirement (1): the content of the polymer block (A) in the block copolymer is 1 to 30% by mass; and

Requirement (2): when the polymer block (B) is regarded as having a structure with a hydrogenation rate of 100 mol %, an average value of a methylene chain length of a main chain of the structural unit derived from at least one selected from the group consisting of a conjugated diene compound and isobutylene is 1.0 to 6.0.

Provided are a novel structure of a copolymer, a preparation method thereof, a vinyl chloride-based resin composition including the copolymer, and a coating ink including the vinyl chloride-based resin composition. According to the present invention, when the vinyl chloride-based resin composition including the copolymer is used, compatibility with ethylene vinyl acetate is excellent, and ink dispersibility and ink color are also excellent.

A process to produce a branched ethylene-α-olefin diene elastomer comprising combining a catalyst precursor and an activator with a feed comprising ethylene, C3 to C12 α-olefins, and a dual-polymerizable diene to obtain a branched ethylene-α-olefin diene elastomer; where the catalyst precursor is selected from pyridyldiamide and quinolinyldiamido transition metal complexes. The branched ethylene-α-olefin diene elastomer may comprise within a range from 40 to 80 wt % of ethylene-derived units by weight of the branched ethylene-α-olefin diene elastomer, and 0.1 to 2 wt % of singly-polymerizable diene derived units, 0.1 to 2 wt % of singly-polymerizable diene derived units, and the remainder comprising C3 to C12 α-olefin derived units, wherein the branched ethylene-α-olefin diene elastomer has a weight average molecular weight (M.sub.w) within a range from 100 kg/mole to 300 kg/mole, an average branching index (g′.sub.avgg) of 0.9 or more, and a branching index at very high M.sub.w (g′.sub.1000) of less than 0.9.

A process to produce a branched ethylene-α-olefin diene elastomer comprising combining a catalyst precursor and an activator with a feed comprising ethylene, C3 to C12 α-olefins, and a dual-polymerizable diene to obtain a branched ethylene-α-olefin diene elastomer; where the catalyst precursor is selected from pyridyldiamide and quinolinyldiamido transition metal complexes. The branched ethylene-α-olefin diene elastomer may comprise within a range from 40 to 80 wt % of ethylene-derived units by weight of the branched ethylene-α-olefin diene elastomer, and 0.1 to 2 wt % of singly-polymerizable diene derived units, 0.1 to 2 wt % of singly-polymerizable diene derived units, and the remainder comprising C3 to C12 α-olefin derived units, wherein the branched ethylene-α-olefin diene elastomer has a weight average molecular weight (M.sub.w) within a range from 100 kg/mole to 300 kg/mole, an average branching index (g′.sub.avgg) of 0.9 or more, and a branching index at very high M.sub.w (g′.sub.1000) of less than 0.9.

A copolymer has low levels of cyclic oligomeric compounds, which are undesirable impurities in certain applications. The cyclic oligomeric compounds are provided in an advantageously low ratio of C21/C13 oligomers. The C13 oligomers are extractable using steam to further reduce the total amount of cyclic oligomers. A process for producing the copolymer having low levels of cyclic oligomers involves contacting at least one isoolefin monomer with at least one multiolefin and/or β-pinene monomer in the presence of at least one Lewis acid and at least one initiator in a diluent. The diluent contains a hydrofluorinated olefin (HFO) comprising at least three carbon atoms and at least three fluorine atoms. Hydrofluorinated olefins used in the present invention are better diluents for butyl slurry cationic polymerization than saturated hydrofluorocarbons.

A copolymer has low levels of cyclic oligomeric compounds, which are undesirable impurities in certain applications. The cyclic oligomeric compounds are provided in an advantageously low ratio of C21/C13 oligomers. The C13 oligomers are extractable using steam to further reduce the total amount of cyclic oligomers. A process for producing the copolymer having low levels of cyclic oligomers involves contacting at least one isoolefin monomer with at least one multiolefin and/or β-pinene monomer in the presence of at least one Lewis acid and at least one initiator in a diluent. The diluent contains a hydrofluorinated olefin (HFO) comprising at least three carbon atoms and at least three fluorine atoms. Hydrofluorinated olefins used in the present invention are better diluents for butyl slurry cationic polymerization than saturated hydrofluorocarbons.

The present invention provides a nitrile group-containing highly saturated copolymer rubber comprising an α,β-ethylenically unsaturated nitrile monomer unit in a content of 15 wt % or more and less than 28 wt %, an α,β-ethylenically unsaturated monocarboxylic acid ester monomer unit (b) in a content of 10 to 50 wt %, and a conjugated diene monomer unit (c) in a content of 22 to 75 wt %, and having an iodine value of 120 or less, wherein the conjugated diene monomer unit (c) is at least partially hydrogenated, and a proportion of an isoprene unit in the conjugated diene monomer unit (c) is 33 wt % or more.