Abstract: A polyimide precursor having a structural unit represented by the following formula (1):

Abstract: A 4-methyl-1-pentene polymer particle (X) which satisfies the following requirements (X-a), (X-b) and (X-c): (X-a) being composed of a 4-methyl-1-pentene polymer which has a content of a constitutional unit derived from 4-methyl-1-pentene being 30.0 to 99.7% by mol, and a content of a constitutional unit derived from at least one olefin selected from ethylene and an ?-olefin having 3 to 20 carbon atoms (except for 4-methyl-1-pentene) being 0.3 to 70.0% by mol; (X-b) having, when measured in a cross fractionation chromatograph apparatus (CFC) using an infrared spectrophotometer as a detector part, at least one peak A of an amount of a component eluted present in the range of 100 to 140° C., and at least one peak B of an amount of a component eluted present at lower than 100° C.; and (X-c) having a meso diad fraction (m) measured by 13C-NMR falling within the range of 95.0 to 100%.

Abstract: A 4-methyl-1-pentene polymer particle (X) which satisfies the following requirements (X-a), (X-b) and (X-c): (X-a) being composed of a 4-methyl-1-pentene polymer which has a content of a constitutional unit derived from 4-methyl-1-pentene being 30.0 to 99.7% by mol, and a content of a constitutional unit derived from at least one olefin selected from ethylene and an ?-olefin having 3 to 20 carbon atoms (except for 4-methyl-1-pentene) being 0.3 to 70.0% by mol; (X-b) having, when measured in a cross fractionation chromatograph apparatus (CFC) using an infrared spectrophotometer as a detector part, at least one peak A of an amount of a component eluted present in the range of 100 to 140° C., and at least one peak B of an amount of a component eluted present at lower than 100° C.; and (X-c) having a meso diad fraction (m) measured by 13C-NMR falling within the range of 95.0 to 100%.

Abstract: A method of production of ethylene-based polymer particles includes the steps of: homopolymerizing ethylene or copolymerizing ethylene and a linear or branched ?-olefin having 3 to 20 carbon atoms in the presence of an olefin polymerization catalyst including: (A) fine particles having an average particle diameter greater than or equal to 1 nm and less than or equal to 300 nm obtained at least by the following two steps: (Step 1) causing contact between a metal halide and an alcohol in a hydrocarbon solvent; (Step 2) causing contact between a component obtained by (Step 1) and an organoaluminum compound and/or an organoaluminumoxy compound; and (B) a transition metal compound represented in General Formula (I) or (II), and (E) an intrinsic viscosity [?] of the ethylene-based polymer particles, measured in decalin at 135° C., is from 5 to 50 dL/g.

Abstract: A method of production of ethylene-based polymer particles includes the steps of: homopolymerizing ethylene or copolymerizing ethylene and a linear or branched ?-olefin having 3 to 20 carbon atoms in the presence of an olefin polymerization catalyst including: (A) fine particles having an average particle diameter greater than or equal to 1 nm and less than or equal to 300 nm obtained at least by the following two steps: (Step 1) causing contact between a metal halide and an alcohol in a hydrocarbon solvent; (Step 2) causing contact between a component obtained by (Step 1) and an organoaluminum compound and/or an organoaluminumoxy compound; and (B) a transition metal compound represented in General Formula (I) or (II), and (E) an intrinsic viscosity [?] of the ethylene-based polymer particles, measured in decalin at 135° C., is from 5 to 50 dL/g.

Abstract: To provide capsular fine particles comprising an olefinic polymer which have a uniform particle size distribution and a uniform particle size, and which are spherical and free from the coagulation between particles. Capsular fine particles comprising the olefinic polymer, of which the ratio (L/M) of the outer diameter (L) to the inner diameter (M) is 1.1 to 6.0, and the average diameter is 0.6 to 40 ?m.

Abstract: Olefin polymer with narrow molecular weight distribution and specific molecular weight, olefin polymer having functional group introduced at terminal, tapered polymer containing segment wherein monomer composition continuously changes in the polymer chain, olefin polymer having different segments bonded to each other, and process for preparing these polymers. The olefin polymers are polymers of C2-20 carbon atom olefins and have a number-average molecular weight of ?500 and Mw/Mn of ?1.5. In syntheses, an olefin of 2-20 carbon atoms is polymerized in the presence of a catalyst comprising a transition metal compound represented by the formula LmMXn wherein M is a transition metal atom of Group 3-11, m is 1-5, n is a number satisfying a valence of M, L is a ligand—coordinated to the central metal M—which contains a heteroatom having no direct bond to the central metal, and X is e.g. halogen or a hydrocarbon.

Abstract: The invention provides transition metal complex compounds, high-activity olefin oligomerization catalysts containing the compounds, and olefin oligomerization processes using the catalysts. A transition metal complex compound [A] according to the invention is represented by Formula (I) or Formula (I?) below. An olefin oligomerization catalyst includes the transition metal complex compound [A]. In an olefin oligomerization process of the invention, an olefin is oligomerized in the presence of the catalyst.

Abstract: The invention provides transition metal complex compounds, high-activity olefin oligomerization catalysts containing the compounds, and olefin oligomerization processes using the catalysts. A transition metal complex compound [A] according to the invention is represented by Formula (I) or Formula (I?) below. An olefin oligomerization catalyst includes the transition metal complex compound [A]. In an olefin oligomerization process of the invention, an olefin is oligomerized in the presence of the catalyst.

Abstract: An ethylene (co)polymer of the present invention is a (co)polymer with excellent moldability and mechanical properties and either an ethylene homopolymer or a copolymer of ethylene and an ?-olefin of 4 to 20 carbon atoms. The (co)polymer has methyl branches measured by 13C-NMR less than 0.1 in number per 1,000 carbon atoms and Mw/Mn measured by GPC not lower than 1.8 and lower than 4.5. The (co)polymer is either an ethylene homopolymer or a copolymer of ethylene and an ?-olefin of 3 to 20 carbon atoms. The melt tension (MT) and the swell ratio (SR) satisfy the relation; log(MT)>12.9?7.15×SR; and the intrinsic viscosity ([?]) and the melt flow rate (MFR) satisfy the relation; [?]>1.85×MFR?0.192 in the case of MFR<1 and the relation; [?]>1.85×MFR?0.213 in the case of MFR?1. Such an ethylene (co)polymer can be usable for various molding applications and especially suitable for pipes.

Abstract: Ethylene-based copolymer microparticles and functional group-containing ethylene-based copolymer microparticles that have particle diameter smaller than that of conventional polyethylene fine-particles, no inter-particle agglomeration, very narrow particle size distribution, and high sphericity are provided, in which requirements (A) to (E): (A) The intrinsic viscosity [?] measured in decalin at 135° C. is in the range of 0.1 to 50 dl/g, (B) at least 95 wt % or more of particles pass through a mesh screen with an opening of 37 ?m, (C) the median diameter (d50) measured by laser diffraction scattering is 3 ?m?d50?25 ?m, (D) the circularity coefficient is 0.85 or more, and (E) the variation coefficient of particle diameter (Cv) is 20% or less. Non-agglomerated spherical magnesium-containing microparticles used as magnesium-containing carrier component for olefin-polymerization catalysts that can manufacture the above microparticles are also provided.

Abstract: The present invention provides an olefin polymer having a narrow molecular weight distribution and a specific molecular weight, an olefin polymer having a functional group introduced at the terminal, a tapered polymer containing a segment wherein monomer composition continuously changes in the polymer chain, an olefin polymer having different segments which are bonded to each other, and a process for preparing these polymers. The olefin polymers of the invention are polymers of olefins of 2 to 20 carbon atoms and have a number-average molecular weight of not less than 500 and Mw/Mn of not more than 1.5.

Abstract: An ethylene (co)polymer of the present invention is a (co)polymer with excellent moldability and mechanical properties and either an ethylene homopolymer or a copolymer of ethylene and an ?-olefin of 4 to 20 carbon atoms. The (co)polymer has methyl branches measured by 13C-NMR less than 0.1 in number per 1,000 carbon atoms and Mw/Mn measured by GPC not lower than 1.8 and lower than 4.5. The (co)polymer is either an ethylene homopolymer or a copolymer of ethylene and an ?-olefin of 3 to 20 carbon atoms. The melt tension (MT) and the swell ratio (SR) satisfy the relation; log(MT)>12.9?7.15×SR; and the intrinsic viscosity ([?]) and the melt flow rate (MFR) satisfy the relation; [?]>1.85×MFR?0.192 in the case of MFR<1 and the relation; [?]>1.85×MFR?0.213 in the case of MFR?1. Such an ethylene (co)polymer can be usable for various molding applications and especially suitable for pipes.

Abstract: The present invention provides an olefin polymer having a narrow molecular weight distribution and a specific molecular weight, an olefin polymer having a functional group introduced at the terminal, a tapered polymer containing a segment wherein monomer composition continuously changes in the polymer chain, an olefin polymer having different segments which are bonded to each other, and a process for preparing these polymers. The olefin polymers of the invention are polymers of olefins of 2 to 20 carbon atoms and have a number-average molecular weight of not less than 500 and Mw/Mn of not more than 1.5.

Abstract: To provide capsular fine particles comprising an olefinic polymer which have a uniform particle size distribution and a uniform particle size, and which are spherical and free from the coagulation between particles. Capsular fine particles comprising the olefinic polymer, of which the ratio (L/M) of the outer diameter (L) to the inner diameter (M) is 1.1 to 6.0, and the average diameter is 0.6 to 40 ?m.

Abstract: An ethylene-based polymer which is a copolymer obtained from ethylene and a C3 to C10?-olefin and satisfies the following requirements (i), (ii), (iii) and (iv) simultaneously provides a blow-molded product and an extrusion-molded product excellent in moldability, mechanical strength and outward appearance. (i) melt flow rate [MFR2 (g/10 min)] under a loading of 2.16 kg at 190° C. is in the range of 0.01 to 10, (ii) melt tension [MT (g)] and the above melt flow rate [MFR2 (g/10 min)] satisfy the following relationship: MT?3.2×MFR2?0.55, (iii) an activation energy [Ea] of fluidization is less than 30 (KJ/mol), and (iv) swell ratio is 1.36 or more.

Abstract: An ethylene (co)polymer of the present invention is a (co)polymer with excellent moldability and mechanical properties and either an ethylene homopolymer or a copolymer of ethylene and an ?-olefin of 4 to 20 carbon atoms. The (co)polymer has methyl branches measured by 13C-NMR less than 0.1 in number per 1,000 carbon atoms and Mw/Mn measured by GPC not lower than 1.8 and lower than 4.5. The (co)polymer is either an ethylene homopolymer or a copolymer of ethylene and an ?-olefin of 3 to 20 carbon atoms. The melt tension (MT) and the swell ratio (SR) satisfy the relation; log(MT)>12.9?7.15×SR; and the intrinsic viscosity ([?]) and the melt flow rate (MFR) satisfy the relation; [?]>1.85×MFR?0.192 in the case of MFR?1 and the relation; [?]>1.85×MFR?0.213 in the case of MFR?1. Such an ethylene (co)polymer can be usable for various molding applications and especially suitable for pipes.

Abstract: Ethylene-based copolymer microparticles and functional group-containing ethylene-based copolymer microparticles that have particle diameter smaller than that of conventional polyethylene fine-particles, no inter-particle agglomeration, very narrow particle size distribution, and high sphericity are provided, in which requirements (A) to (E): (A) The intrinsic viscosity [?] measured in decalin at 135° C. is in the range of 0.1 to 50 dl/g, (B) at least 95 wt % or more of particles pass through a mesh screen with an opening of 37 ?m, (C) the median diameter (d50) measured by laser diffraction scattering is 3 ?m?d50?25 ?m, (D) the circularity coefficient is 0.85 or more, and (E) the variation coefficient of particle diameter (Cv) is 20% or less. Non-agglomerated spherical magnesium-containing microparticles used as magnesium-containing carrier component for olefin-polymerization catalysts that can manufacture the above microparticles are also provided.

Abstract: The present invention provides a novel olefin polymerization catalyst having excellent olefin polymerization activity and, in polymerization with the catalyst comprising a transition metal compound, a polymerization process for preparing a polymer having a low molecular weight with high polymerization activity. The process comprises polymerizing olefin in the presence of an olefin polymerization catalyst comprising (A) a transition metal compound represented by the following [M: a Group 4 or 5 transition metal atom in the Periodic Table, m: 1–4, R1: H, a C1–C5 linear hydrocarbon group, 3- to 5-membered alicyclic hydrocarbon group, bicycloaliphatic hydrocarbon group wherein two alicyclic rings share one or more carbon atoms, R2 to R6: H, a halogen atom, hydrocarbon group etc, X: H, a halogen atom etc, and n is a valence of M], and (B) at least one compound selected from (B-1) an organometallic compound, (B-2) an organoaluminum oxy compound and (B-3) an ionizing ionic compound.

Abstract: An ethylene-based polymer which is a copolymer obtained from ethylene and a C3 to C10?-olefin and satisfies the following requirements (i), (ii), (iii) and (iv) simultaneously provides a blow-molded product and an extrusion-molded product excellent in moldability, mechanical strength and outward appearance. (i) melt flow rate [MFR2 (g/10 min)] under a loading of 2.16 kg at 190° C. is in the range of 0.01 to 10, (ii) melt tension [MT (g)] and the above melt flow rate [MFR2 (g/10 min)] satisfy the following relationship: MT?3.2×MFR2?0.55, (iii) an activation energy [Ea] of fluidization is less than 30 (KJ/mol), and (iv) swell ratio is 1.36 or more.

Abstract: A thin film magnetic head comprises a slider and a reading/writing element attached to an end surface of the slider, wherein the reading/writing element is disposed at an end surface in the longitudinal direction of the slider when the longitudinal direction and the width direction are determined on the surface which faces a magnetic recording medium, of the slider, and the slider has a linear groove in the surface opposite the surface which faces the magnetic recording medium, at the intermediate portion in the width direction of the slider and along the longitudinal direction.