An object of the present invention is to provide a production method of a diene-based polymer that can control the crosslinking morphology. The present invention provides a method for producing a modified diene-based polymer having a structure represented by the formula (1), comprising a first step of mixing a diene-based polymer and a dithioester compound to prepare a mixture; and a second step of irradiating a ray to the mixture under an inert atmosphere.

##STR00001##

[In the formula (1), R.sup.1 and R.sup.2 represent an alkyl group having 1 or more carbon atoms, an aryl group having 6 or more carbon atoms, an aralkyl group having 6 or more carbon atoms, a hydrogen atom, or a halogen atom; and Z is an organic group, an organic group where a part of hydrogen atom of the above organic group is substituted, a hydrogen atom, or a halogen atom.]

An ethylene alpha-olefin copolymer having (a) a density of from about 0.910 g/cc to about 0.940 g/cc; (b) a weight average molecular weight of from about 150,000 g/mol to about 300,000 g/mol; and (c) a melt index at a load of 2.16 kg of from about 0.01 dg/10 min. to about 0.5 dg/min.; wherein a 1 mil blown film formed from the polymer composition is characterized by (i) a Dart Impact strength greater than about 175 g/mil; (ii) an Elmendorf machine direction tear strength greater than about 20 g/mil; and (iii) an Elmendorf transverse direction tear strength greater than about 475 g/mil.

An ethylene alpha-olefin copolymer having (a) a density of from about 0.910 g/cc to about 0.940 g/cc; (b) a weight average molecular weight of from about 150,000 g/mol to about 300,000 g/mol; and (c) a melt index at a load of 2.16 kg of from about 0.01 dg/10 min. to about 0.5 dg/min.; wherein a 1 mil blown film formed from the polymer composition is characterized by (i) a Dart Impact strength greater than about 175 g/mil; (ii) an Elmendorf machine direction tear strength greater than about 20 g/mil; and (iii) an Elmendorf transverse direction tear strength greater than about 475 g/mil.

[Problem to be Solved]

There is provided a process for producing an olefin polymer that is capable of producing an olefin polymer having high heat resistance and high molecular weight with excellent catalytic activity.

[Solution to Problem]

The process for producing an olefin polymer includes a step of polymerizing at least one olefin selected from ethylene and α-olefins having 4 to 30 carbon atoms in the presence of an olefin polymerization catalyst containing a transition metal compound represented by the general formula [I], the olefin polymer including constituent units derived from ethylene and α-olefins having 4 to 30 carbon atoms in a total amount between more than 50 mol % and not more than 100 mol %,

##STR00001##

[in the formula [I], R.sup.1, R.sup.3 and R.sup.5 to R.sup.16 are each independently a hydrogen atom, a hydrocarbon group or the like; R.sup.2 is a hydrocarbon group or the like; R.sup.4 is a hydrogen atom; M is a transition metal of Group IV; Q is a halogen atom or the like; and j is an integer of 1 to 4].

[Problem to be Solved]

There is provided a process for producing an olefin polymer that is capable of producing an olefin polymer having high heat resistance and high molecular weight with excellent catalytic activity.

[Solution to Problem]

The process for producing an olefin polymer includes a step of polymerizing at least one olefin selected from ethylene and α-olefins having 4 to 30 carbon atoms in the presence of an olefin polymerization catalyst containing a transition metal compound represented by the general formula [I], the olefin polymer including constituent units derived from ethylene and α-olefins having 4 to 30 carbon atoms in a total amount between more than 50 mol % and not more than 100 mol %,

##STR00001##

[in the formula [I], R.sup.1, R.sup.3 and R.sup.5 to R.sup.16 are each independently a hydrogen atom, a hydrocarbon group or the like; R.sup.2 is a hydrocarbon group or the like; R.sup.4 is a hydrogen atom; M is a transition metal of Group IV; Q is a halogen atom or the like; and j is an integer of 1 to 4].

[Problem to be Solved]

There is provided a process for producing an olefin polymer that is capable of producing an olefin polymer having high heat resistance and high molecular weight with excellent catalytic activity.

[Solution to Problem]

The process for producing an olefin polymer includes a step of polymerizing at least one olefin selected from ethylene and α-olefins having 4 to 30 carbon atoms in the presence of an olefin polymerization catalyst containing a transition metal compound represented by the general formula [I], the olefin polymer including constituent units derived from ethylene and α-olefins having 4 to 30 carbon atoms in a total amount between more than 50 mol % and not more than 100 mol %,

##STR00001##

[in the formula [I], R.sup.1, R.sup.3 and R.sup.5 to R.sup.16 are each independently a hydrogen atom, a hydrocarbon group or the like; R.sup.2 is a hydrocarbon group or the like; R.sup.4 is a hydrogen atom; M is a transition metal of Group IV; Q is a halogen atom or the like; and j is an integer of 1 to 4].

Vanadium phosphinic complex having general formula (I) or (II): V(X)M3P̂WFys-nMO V(X)3[(R3)2P(R4)P(R3)2] (ID wherein: X represents an anion selected from halogens such as, for example, chlorine, bromine, iodine, preferably chlorine; or is selected from the following groups: thiocyanate, isocyanate, sulfate, acid sulfate, phosphate, acid phosphate, carboxylate, dicarboxylate; Ri, identical or different among them, represent a hydrogen atom, or an allyl group (CH2=CH—CH2-); or are selected from alkyl groups CrC2o, preferably CrĈ, linear or branched, optionally halogenated, optionally substituted cycloalkyl groups; —n is an integer ranging from 0 to 3; R2, identical or different among them, are selected from optionally substituted aryl groups; R3, identical or different among them, represent a hydrogen atom, or an allyl group (CH2=CH—CH2-); or are selected from alkyl groups C1-C2o, preferably CrĈ, linear or branched, optionally halogenated, optionally substituted cycloalkyl groups, optionally substituted aryl groups; R4 represents a group —NR5 wherein R5 represents a hydrogen atom, or is selected from C1-C20 alkyl groups, preferably CrC15, linear or branched; or R4 represents an alkylene group —(CH2) p- wherein p represents an integer ranging from 1 to 5; provided that in the general formula (I), in case n is equal to 1 and Ri is methyl, R2 is different from phenyl. Said phosphinic vanadium complex having general formula (I) or (II) can be advantageously used in a catalytic system for the (co)polymerization of conjugated dienes.

Vanadium phosphinic complex having general formula (I) or (II): V(X)M3P̂WFys-nMO V(X)3[(R3)2P(R4)P(R3)2] (ID wherein: X represents an anion selected from halogens such as, for example, chlorine, bromine, iodine, preferably chlorine; or is selected from the following groups: thiocyanate, isocyanate, sulfate, acid sulfate, phosphate, acid phosphate, carboxylate, dicarboxylate; Ri, identical or different among them, represent a hydrogen atom, or an allyl group (CH2=CH—CH2-); or are selected from alkyl groups CrC2o, preferably CrĈ, linear or branched, optionally halogenated, optionally substituted cycloalkyl groups; —n is an integer ranging from 0 to 3; R2, identical or different among them, are selected from optionally substituted aryl groups; R3, identical or different among them, represent a hydrogen atom, or an allyl group (CH2=CH—CH2-); or are selected from alkyl groups C1-C2o, preferably CrĈ, linear or branched, optionally halogenated, optionally substituted cycloalkyl groups, optionally substituted aryl groups; R4 represents a group —NR5 wherein R5 represents a hydrogen atom, or is selected from C1-C20 alkyl groups, preferably CrC15, linear or branched; or R4 represents an alkylene group —(CH2) p- wherein p represents an integer ranging from 1 to 5; provided that in the general formula (I), in case n is equal to 1 and Ri is methyl, R2 is different from phenyl. Said phosphinic vanadium complex having general formula (I) or (II) can be advantageously used in a catalytic system for the (co)polymerization of conjugated dienes.

The purpose of the present invention is to provide a method for efficiently producing an olefin (co)polymer containing a constituent unit derived from 1-butene, the (co)polymer having a molecular weight that is sufficiently high even for high temperature conditions that are beneficial for industrial production methods. This purpose can be achieved by means of a method for producing an olefin (co)polymer containing a constituent unit derived from 1-butene, wherein at least 1-butene and, if necessary, an α-olefin having 2 or more carbon atoms (excluding 1-butene) and other monomers are (co)polymerized in the presence of an olefin polymerization catalyst that contains (A) a crosslinked metallocene compound represented by general formula [I] and (B) at least one type of compound selected from among (b-1) an organic aluminum oxy compound, (b-2) a compound that forms an ion pair upon a reaction with the crosslinked metallocene compound (A), and (b-3) an organic aluminum compound, at a polymerization temperature of 55-200° C. and a polymerization pressure of 0.1-5.0 MPaG.

The purpose of the present invention is to provide a method for efficiently producing an olefin (co)polymer containing a constituent unit derived from 1-butene, the (co)polymer having a molecular weight that is sufficiently high even for high temperature conditions that are beneficial for industrial production methods. This purpose can be achieved by means of a method for producing an olefin (co)polymer containing a constituent unit derived from 1-butene, wherein at least 1-butene and, if necessary, an α-olefin having 2 or more carbon atoms (excluding 1-butene) and other monomers are (co)polymerized in the presence of an olefin polymerization catalyst that contains (A) a crosslinked metallocene compound represented by general formula [I] and (B) at least one type of compound selected from among (b-1) an organic aluminum oxy compound, (b-2) a compound that forms an ion pair upon a reaction with the crosslinked metallocene compound (A), and (b-3) an organic aluminum compound, at a polymerization temperature of 55-200° C. and a polymerization pressure of 0.1-5.0 MPaG.