A solid catalyst component for olefin polymerization, an olefin polymerization catalyst, and a method for producing an olefin polymer, are disclosed. A solid catalyst component for olefin polymerization includes magnesium, a halogen, titanium, vanadium, and an internal electron donor compound selected by organic acid diester. An olefin polymerization catalyst includes the disclosed solid catalyst component for olefin polymerization, an organoaluminum promoter, and an optional external electron donor A method for producing an olefin copolymer includes copolymerizing ethylene and propylene using the disclosed olefin polymerization catalyst.

This invention relates to polyolefin. More specifically, this invention relates to polyolefin that has small copolymer content, but exhibits excellent mechanical properties.

Bimodal high density polyethylene compositions can achieve an improved balance of stress crack resistance and processability by selecting the higher molecular weight and lower molecular weight components such that (1) the lower molecular weight component has a relatively high complementary density, which is a calculated property shown by the formula below, and (2) the higher molecular weight component of the composition has a moderately-low density and narrow molecular weight distribution. This combination of properties provides improved balance of stress crack resistance and processability without having to modify the properties of the higher molecular weight component.

The use of a block copolymer of the following structure. Wherein R and R.sup.1 may be the same or different and each independently represents an alkyl or aryl group, X may be hydrogen or C.sub.1 to C.sub.20 alkyl group which may be branched or linear and wherein the aromatic ring substituent joined to polymer B is positioned meta or para to the aromatic ring substituent joined to polymer A and, wherein polymer A is a polymer (or copolymer) of ethylene and polymer B is a polymer of monomers selected from vinyl acetate, C.sub.1-C.sub.9 acrylate esters, acrylic acid and mixtures thereof as an additive in polyethylene or polyethylene terephthalate to improve the adhesion between co-extruded layers of the polyethylene and the polyethylene terephthalate and laminated films derived from such use. ##STR00001##

A method for producing a propylene-based block copolymer ensures excellent olefin polymerization activity and activity with respect to hydrogen (hydrogen response) during polymerization, and produces a propylene-based block copolymer that exhibits a high MFR, high stereoregularity, and excellent rigidity. The method includes copolymerizing propylene and an ?-olefin in the presence of a catalyst that includes (I) a solid catalyst component that includes titanium, magnesium, a halogen, and a compound represented by R.sup.1OC(?O)OZOR.sup.2, and (II) a compound represented by R.sup.3.sub.pAlQ.sub.3-p, to obtain a propylene-based block copolymer.

A method for producing a propylene-based block copolymer ensures excellent olefin polymerization activity and activity with respect to hydrogen (hydrogen response) during polymerization, and produces a propylene-based block copolymer that exhibits a high MFR, high stereoregularity, and excellent rigidity. The method includes copolymerizing propylene and an ?-olefin in the presence of a catalyst that includes (I) a solid catalyst component that includes titanium, magnesium, a halogen, and a compound represented by R.sup.1OC(?O)OZOR.sup.2, and (II) a compound represented by R.sup.3.sub.pAlQ.sub.3-p, to obtain a propylene-based block copolymer.

A resin composition according to an aspect of the present invention comprises: an ethylene-vinyl alcohol copolymer (A); and a block copolymer (B) having a block (b1) that includes a vinyl aromatic monomer unit, and a block (b2) that includes an isobutylene unit, wherein the ethylene-vinyl alcohol copolymer (A) and the block copolymer (B) form a co-continuous phase structure; and a DSC curve obtained following heating the resin composition up to a melting point and cooling at a rate of 50 C./min in a differential scanning calorimetry analysis shows two peaks, with a higher peak top temperature falling within a range of 130 C. or greater and 170 C. or less, and a lower peak top temperature falling within a range of 100 C. or greater and less than 130 C. A resin composition may thus be obtained that is able to give a molded article that is superior in balance between gas barrier properties and flexibility.

A resin composition according to an aspect of the present invention comprises: an ethylene-vinyl alcohol copolymer (A); and a block copolymer (B) having a block (b1) that includes a vinyl aromatic monomer unit, and a block (b2) that includes an isobutylene unit, wherein the ethylene-vinyl alcohol copolymer (A) and the block copolymer (B) form a co-continuous phase structure; and a DSC curve obtained following heating the resin composition up to a melting point and cooling at a rate of 50 C./min in a differential scanning calorimetry analysis shows two peaks, with a higher peak top temperature falling within a range of 130 C. or greater and 170 C. or less, and a lower peak top temperature falling within a range of 100 C. or greater and less than 130 C. A resin composition may thus be obtained that is able to give a molded article that is superior in balance between gas barrier properties and flexibility.

An object of the present invention is to provide expanded beads capable of producing an expanded beads molded article that is excellent in in-mold moldability and is excellent with good balance in lightweight property, flexibility, repulsion, restorability, and tensile characteristics, and an expanded beads molded article using the expanded beads. For achieving the object, the present invention provides crosslinked expanded beads produced by crosslinking and expanding particles containing a multi-block copolymer containing a polyethylene block and an ethylene--olefin copolymer block, the multi-block copolymer having a melt flow rate of from 2 to 10 g/10 min at 190 C. and a load of 2.16 kg, and a Shore A hardness of from 65 to 90 measured according to ASTM D2240, the crosslinked expanded beads having a gel fraction of from 30 to 60% by a hot xylene extraction method. The expanded beads molded article of the present invention is produced by subjecting the crosslinked expanded beads of the present invention, to in-mold molding. The expanded beads molded article of the present invention may have an apparent density of from 40 to 150 g/L.

A method for producing a thermoplastic elastomer includes forming a first block by copolymerizing a C4-C7 isoolefin monomer and alkylstyrene in the presence of a polymerization initiator; and forming a second block by polymerizing aromatic vinyl monomers. The thermoplastic elastomer comprises the first block and the second block. An amount of unreacted portion of the alkylstyrene during the formation of the first block is maintained at a molar ratio of not more than 1/90 relative to a total amount of the isoolefin monomer. The alkylstyrene is represented by the general formula (1), and the polymerization initiator is represented by the general formula (2).