The present invention relates to polyolefin. More specifically, the present invention relates to polyolefin having excellent dart drop impact strength, and exhibiting improved transparency, and such polyolefin has a density of 0.915 g/cm3 to 0.930 g/cm3 measured according to ASTM D1505; and satisfies the following requirements (provided that S1+S2+S3=1), when measuring the relative content of peak area according to melting temperature (Tm) using SSA (Successive Self-nucleation and Annealing) analysis: the content(S1) of peak area at Tm less than 100° C. is 0.33 to 0.35; the content(S2) of peak area at Tm of 100° C. or more and 120° C. or less is 0.52 to 0.56; and the content(S3) of peak area at Tm greater than 120° C. is 0.10 to 0.14.

The present invention relates to use of optionally monosubstituted 2,2-di(tetrahydrofuryl)methanes, as internal donors in Ziegler-Natta catalysts to obtain polymers with desirable properties. The present disclosure further concerns Ziegler-Natta catalyst components comprising said optionally monosubstituted 2,2-di(tetrahydrofuryl)methanes and Ziegler-Natta catalysts for olefin polymerization comprising said Ziegler-Natta catalyst components as well as a method for preparing the same and their use in providing polyolefins.

The present invention relates to use of optionally monosubstituted 2,2-di(tetrahydrofuryl)methanes, as internal donors in Ziegler-Natta catalysts to obtain polymers with desirable properties. The present disclosure further concerns Ziegler-Natta catalyst components comprising said optionally monosubstituted 2,2-di(tetrahydrofuryl)methanes and Ziegler-Natta catalysts for olefin polymerization comprising said Ziegler-Natta catalyst components as well as a method for preparing the same and their use in providing polyolefins.

A process for propylene preliminary polymerization in liquid phase that occurs in a continuous preliminary polymerization reactor may include feeding a propylene monomer and a Ziegler-Natta catalyst system having (a) a pro-catalyst having an internal electron donor comprising a substituted phenylene aromatic diester, (b) a catalyst activator and optionally (c) an external donor, into the continuous preliminary polymerization reactor, wherein the feeding is carried out without pre-contact of the pro-catalyst with the catalyst activator, and also without pre-contact of the catalyst activator with the propylene monomer before entering the continuous preliminary polymerization reactor.

A process for propylene preliminary polymerization in liquid phase that occurs in a continuous preliminary polymerization reactor may include feeding a propylene monomer and a Ziegler-Natta catalyst system having (a) a pro-catalyst having an internal electron donor comprising a substituted phenylene aromatic diester, (b) a catalyst activator and optionally (c) an external donor, into the continuous preliminary polymerization reactor, wherein the feeding is carried out without pre-contact of the pro-catalyst with the catalyst activator, and also without pre-contact of the catalyst activator with the propylene monomer before entering the continuous preliminary polymerization reactor.

Processes of polymerizing olefins include contacting ethylene, a (C.sub.3-C.sub.40)alpha-olefin comonomer, and a solvent in the presence of a chain transfer agent and a catalyst system, the catalyst system comprising a metal-ligand complex according to formula (I).

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Processes of polymerizing olefins include contacting ethylene, a (C.sub.3-C.sub.40)alpha-olefin comonomer, and a solvent in the presence of a chain transfer agent and a catalyst system, the catalyst system comprising a metal-ligand complex according to formula (I).

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Embodiments are directed towards the use of a supported biphenylphenol polymerization catalyst made from a biphenylphenol polymerization precatalyst of Formula I via a gas-phase or slurry-phase polymerization process under gas-phase or slurry-phase polymerization conditions to make a polymer.

Embodiments are directed towards the use of a supported biphenylphenol polymerization catalyst made from a biphenylphenol polymerization precatalyst of Formula I via a gas-phase or slurry-phase polymerization process under gas-phase or slurry-phase polymerization conditions to make a polymer.

A light shielding member of the present invention includes a first polarizing plate, a second polarizing plate facing the first polarizing plate, and a thermosensitive sheet interposed between the first polarizing plate and the second polarizing plate, in which the first polarizing plate and the second polarizing plate are positioned so that their respective transmission axes are different from each other, and the thermosensitive sheet contains a side chain crystal polymer that crystallizes at a temperature lower than the melting point and exhibits fluidity at a temperature of the melting point or higher. The light shielding member may transmit light at a temperature lower than the melting point and may not transmit light at a temperature of the melting point or higher, when light travels from one of the first polarizing plate and the second polarizing plate toward the other.