Non-coordinating borate activators deposited upon a support material may be effective for promoting olefin polymerization in the presence of a suitable transition metal complex, particularly for gas phase and slurry polymerization reactions. The non-coordinating borate activators may be deposited upon the support material using substantially aliphatic hydrocarbon solvents, preferably in the absence of aromatic solvents, such as toluene.

The present invention relates to an anionic polymerization initiator represented by Formula 1 below for producing a polyolefin-polystyrene block copolymer, an anionic polymerization initiator composition, and a production method therefor,

##STR00001##

wherein R.sub.1, and A are described herein.

The present invention relates to an anionic polymerization initiator represented by Formula 1 below for producing a polyolefin-polystyrene block copolymer, an anionic polymerization initiator composition, and a production method therefor,

##STR00001##

wherein R.sub.1, and A are described herein.

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.

The present disclosure relates to a method for preparing a polyolefin using a supported hybrid metallocene catalyst. According to the present disclosure, a polyolefin having a narrow molecular weight distribution can be prepared very effectively by introducing a cocatalyst in an optimum content in the presence of a supported hybrid metallocene catalyst containing two or more metallocene compounds having a specific chemical structure. The polyolefin prepared according to the present disclosure exhibits excellent uniformity in chlorine distribution in polyolefin during chlorination, thereby significantly improving elongation of the chlorinated polyolefin, compatibility with PVC and impact reinforcing performance. Thus, it exhibits excellent chemical resistance, weather resistance, flame retardancy, processability and impact strength reinforcing effect, and can be suitably applied as an impact reinforcing agent for PVC pipes and window profiles.

The polyethylene according to the present invention has narrow particle size distribution, and can minimize a change in the crystal structure, and thus, it can be reacted with chlorine to prepare chlorinated polyethylene having excellent chlorination productivity and thermal stability.

The present invention relates to an olefin-based polymer, which has (1) a density (d) ranging from 0.85 to 0.90 g/cc, (2) a melt index (MI, 190° C., 2.16 kg load conditions) ranging from 0.1 g/10 min to 15 g/10 min, (3) the density (d) and the melt temperature (Tm) satisfying Tm (° C.)=a×d−b of Equation 1 (2,350<a<2,500, and 1,900<b<2,100), and (4) a ratio (hardness/Tm) of the hardness (shore A) to the melt temperature (Tm) in a range of 1.0 to 1.3. The olefin-based polymer according to the present invention exhibits excellent anti-blocking properties due to having improved hardness as a low-density olefin-based polymer.

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.

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.