A biaxially-oriented film comprising a polyethylene having (A) a melt flow index of 1.0 g/10 min or more, (B) a density of 0.90 g/cm3 to less than 0.940 g/cm.sup.3, (C) a g′.sub.LCB of greater than 0.8, (D) ratio of comonomer content at Mz to comonomer content at Mw is greater than 1.0, (E) ratio of comonomer content at Mn to comonomer content at Mw is greater than 1.0, and (F) a ratio of the g′.sub.LCB to the g′.sub.zave is greater than 1.0, and where the film has a 1% secant in the transverse direction of 70,000 psi or more and Dart Drop of 350 g/mil or more.

A borate compound-composition may contain soluble in hydrocarbon solvents and useful as a cocatalyst for solution polymerization of olefins or dienes. A composition containing a compound of formula (1)

##STR00001##

and
a compound of formula (4):

##STR00002##

wherein each symbol is as defined in the specification, which is useful as a cocatalyst for polymerization of olefins or dienes, and a production method thereof can be provided.

A borate compound-containing composition soluble in hydrocarbon solvents. A composition containing base A, or a compound having a total carbon number of not less than 8 and represented by the formula (5):

##STR00001##

wherein R and R′ are each independently an optionally substituted C.sub.1-30 alkyl group, an optionally substituted C.sub.3-15 cycloalkyl group, or an optionally substituted C.sub.6-14 aryl group; and
a borate compound represented by the following formula (1):

##STR00002##

wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently a C.sub.6-14 aryl group substituted by one or more fluorine atoms or fluoro C.sub.1-4 alkyl groups; and
[A-H].sup.+ is a base A-derived cation. A method for producing a polymer, by polymerizing at least one kind of monomer selected from the group consisting of olefins and dienes by using the composition A as a cocatalyst.

A borate compound-containing composition soluble in hydrocarbon solvents. A composition containing base A, or a compound having a total carbon number of not less than 8 and represented by the formula (5):

##STR00001##

wherein R and R′ are each independently an optionally substituted C.sub.1-30 alkyl group, an optionally substituted C.sub.3-15 cycloalkyl group, or an optionally substituted C.sub.6-14 aryl group; and
a borate compound represented by the following formula (1):

##STR00002##

wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently a C.sub.6-14 aryl group substituted by one or more fluorine atoms or fluoro C.sub.1-4 alkyl groups; and
[A-H].sup.+ is a base A-derived cation. A method for producing a polymer, by polymerizing at least one kind of monomer selected from the group consisting of olefins and dienes by using the composition A as a cocatalyst.

This invention relates to a biaxially-oriented polyethylene film comprising polyethylene having: (A) a melt index, I.sub.2, of 1.0 g/10 min or greater; (B) a density of 0.925 g/cm.sup.3 to 0.945 g/cm.sup.3; (C) a g′.sub.vis of less than 0.8; (D) an Mz of 1,000,000 g/mol or more; (E) an Mw/Mn of 5 or more; (F) an Mw of 100,000 g/mol or more; (G) a ratio of the g′.sub.LCB to the g′.sub.Zave is greater than 1.0; and (H) a Strain Hardening Ratio of 4 or more, where the film has a 1% secant in the transverse direction of 60,000 psi or more, a Dart Drop of 250 g/mil or more, and a ratio of 1% secant MD/1% secant TD is 0.65 or more.

This invention relates to a biaxially-oriented polyethylene film comprising polyethylene having: (A) a melt index, I.sub.2, of 1.0 g/10 min or greater; (B) a density of 0.925 g/cm.sup.3 to 0.945 g/cm.sup.3; (C) a g′.sub.vis of less than 0.8; (D) an Mz of 1,000,000 g/mol or more; (E) an Mw/Mn of 5 or more; (F) an Mw of 100,000 g/mol or more; (G) a ratio of the g′.sub.LCB to the g′.sub.Zave is greater than 1.0; and (H) a Strain Hardening Ratio of 4 or more, where the film has a 1% secant in the transverse direction of 60,000 psi or more, a Dart Drop of 250 g/mil or more, and a ratio of 1% secant MD/1% secant TD is 0.65 or more.

The present invention relates to a new multimodal ethylene copolymer (P), to the use of the copolymer in film applications and to a film comprising the copolymer of the invention.

The present invention relates to a new multimodal ethylene copolymer (P), to the use of the copolymer in film applications and to a film comprising the copolymer of the invention.

Catalyst system, the catalyst system comprising (i) at least one metallocene complex of formula (I) wherein Mt1 is Hf, X is a sigma-donor ligand, R.sup.1, R.sup.2, R.sup.3 are the same or different from each other and can be hydrogen or a saturated linear or branched C.sub.1-C.sub.10 alkyl, whereby the alkyl group can optionally contain up to 2 heteroatoms belonging to groups 14-16 of the periodic table, or R.sup.1 and R.sup.2 or R.sup.2 and R.sup.3 can form a ring having 4 to 6 C-atoms and 1 to 3 double bonds, R.sup.4 and R.sup.5 are the same or different from each other and can be saturated linear or branched C.sub.1-C.sub.10 alkyl, C.sub.5-C.sub.10 aryl, C.sub.6-C.sub.20 alkylaryl or C.sub.6-C.sub.20 arylalkyl groups, which can optionally contain up to 2 heteroatoms belonging to groups 14-16 of the periodic table, n can be 1 to 5, Ar is a C.sub.6-C.sub.20-aryl or -heteroaryl group, which can be unsubstituted or substituted by 1 to 5 linear or branched C.sub.1-C.sub.10 alkyl group(s), and (ii) an aluminoxane cocatalyst and (iii) optionally an aluminium alkyl compound AI(R.sup.7).sub.3, with R.sup.7 being a linear or branched C.sub.2-C.sub.8-alkyl group. ##STR00001##

Catalyst system, the catalyst system comprising (i) at least one metallocene complex of formula (I) wherein Mt1 is Hf, X is a sigma-donor ligand, R.sup.1, R.sup.2, R.sup.3 are the same or different from each other and can be hydrogen or a saturated linear or branched C.sub.1-C.sub.10 alkyl, whereby the alkyl group can optionally contain up to 2 heteroatoms belonging to groups 14-16 of the periodic table, or R.sup.1 and R.sup.2 or R.sup.2 and R.sup.3 can form a ring having 4 to 6 C-atoms and 1 to 3 double bonds, R.sup.4 and R.sup.5 are the same or different from each other and can be saturated linear or branched C.sub.1-C.sub.10 alkyl, C.sub.5-C.sub.10 aryl, C.sub.6-C.sub.20 alkylaryl or C.sub.6-C.sub.20 arylalkyl groups, which can optionally contain up to 2 heteroatoms belonging to groups 14-16 of the periodic table, n can be 1 to 5, Ar is a C.sub.6-C.sub.20-aryl or -heteroaryl group, which can be unsubstituted or substituted by 1 to 5 linear or branched C.sub.1-C.sub.10 alkyl group(s), and (ii) an aluminoxane cocatalyst and (iii) optionally an aluminium alkyl compound AI(R.sup.7).sub.3, with R.sup.7 being a linear or branched C.sub.2-C.sub.8-alkyl group. ##STR00001##