Abstract: A thermoplastic elastomer having adhesion to steels, where the thermoplastic elastomer includes a dynamically crosslinked rubber, from more than 2.0 to 10 parts of a metal oxide or salt, and from 10 to 200 parts by weight of a functionalized polyolefin having pendant polar functional groups, where the polar functional groups are present at a level of 0.5 to 3.5 mole percent of the total repeating units of said functionalized polyolefin and the functionalized polyolefin is derived from polymerizing at least one monoolefin to form a semicrystalline polymer or is derived from hydrogenating the polydiene blocks of a block copolymer, and where the parts by weight are based on 100 parts by weight of crosslinked rubber.

Abstract: A process for producing a modified polymer rubber comprising the steps of: (1) polymerizing a conjugated diene monomer or a combination thereof with an aromatic vinyl monomer in a hydrocarbon solvent, in the presence of an alkali metal catalyst or a specified alkali metal compound, to form an alkali metal end-carrying active polymer, and (2) reacting the alkali metal end-carrying active polymer with a specified isocyanurate compound or a combination thereof with a specified coupling agent in a hydrocarbon solvent.

Abstract: Provided is a process for producing a cycloolefin resin composition, comprising a step of hydrogenating a resin composition. The resin composition before hydrogenation, which is used in the above step, includes 0.01 to 20 parts by weight of an unsaturated hydrocarbon compound having a boiling point of 50° C. or higher, for example, a monomer employed in polymerization, per 100 parts by weight of the resin composition.

Abstract: The residual chlorine content of a polyolefin-substituted carboxylic acylating agent formed by a halogen-assisted reaction of a polyalkene and at least one olefinic, monounsaturated mono- or dicarboxylic acid, anhydride or ester, is reduced when the reaction is conducted in the presence of a controlled amount of a metal compound.

Abstract: Golf balls including centers formed from polybutadiene reaction products having a percent change in dynamic stiffness from 0° C. to ?50° C. of less than 130 percent where the reaction products include a resilient polymer component, a crosslinking material, a cis-to-trans catalyst, and a free radical source. The golf balls may be formed with polyurethane covers, covers formed from castable reactive liquid materials, among other materials. The golf balls may also include an intermediate layer.

Abstract: There are disclosed star shaped thermoplastic elastomers made of acrylic block copolymers obtained by transition metal catalysed radical polymerisation. The elastomers comprise core arms obtained from monomers or mixture of monomers, whose Tg is from about ?65° C. to about ?20° C., and of shell arms obtained from monomers or mixture of monomers, whose Tg is from about 70° C. to about 160° C. The core copolymer has a polydispersity of 2 or higher and the final copolymer has a polydispersity of from 3 to 10.

Abstract: A low compression, resilient golf ball having a center including a material formed from the conversion reaction of sufficient amounts of polybutadiene, a free radical source, and a cis-to-trans catalyst to convert a portion of cis-isomer to trans-isomer in the polybutadiene, wherein said material has an amount of trans-isomer greater than the amount of trans-isomer present before the conversion reaction, and wherein the reaction product includes low levels or substantially no antioxidant.

Abstract: A golf ball including a solid core formed from a composition comprising a diene rubber, a metallic fatty acid salt present in an amount of from 6.3 parts to 7.5 parts, a cis-to-trans catalyst present in an amount of 2.35 parts or greater, and an organic peroxide present in an amount of 0.8 parts or less; and a cover; wherein the core has a coefficient of restitution of 0.810 or greater and a compression of 58 to 78.

Abstract: The present invention relates to novel functional norbornenes as initiators for radical polymerization, its polymer and a process for producing the same. More particularly, the novel functional norbornenes can be selectively polymerized by ring-opening metathesis polymerization or radical polymerization to obtain various polynorbornene derivatives or grafted copolymer materials. The polynorbornene derivatives and grafted copolymer materials not only exhibit excellent functional properties but also enhanced physical and chemical properties after modification. The polynorbornene derivatives and grafted copolymer materials disclosed in the present invention exhibit excellent heat resistance, transparency and water resistance. The present invention also deals with a process for producing such derivatives and materials having controllable molecular weight with narrow molecular weight distribution.

Abstract: A golf ball comprising a core, an outer cover layer, and, optionally, an intermediate layer disposed between the core and the outer cover layer is presently disclosed.

Abstract: Methods are described for preparing graft copolymers from poly(vinyl chloride) or vinyl chloride copolymers comprising reacting these materials with sources of selected metal-centered free radicals in the presence of one or more monomers that can undergo free-radical addition polymerization. The metal-centered free radicals used are capable of abstracting chlorine atoms from the starting polymer to form C-centered radicals that add to the monomer(s) in order to start the growth of branches via a free-radical route. This method is an effective method for producing PVC graft copolymers, and can be used to produce PVC graft copolymers having novel compositions. The methods of the invention are particularly useful for providing highly branched PVC graft copolymers.

Abstract: A novel polyolefin graft copolymer prepared by graft-copolymerizing an olefin monomer with a (meth)acryl macromonomer or an isobutylene macromonomer in the presence of a coordination polymerization catalyst based on a late transition metal complex and a method for making the novel polyolefin graft copolymer are provided.

Abstract: The present invention provides a hot-melt adhesive composition comprising a blend of: a reactive filler comprising an aluminum compound, a magnesium compound, a calcium compound, a barium compound or a mixture thereof; and, a grafted polyolefin having a functional group for reaction with the reactive filler. Such a hot-melt adhesive is particularly useful for bonding a polyolefin-based substrate to dissimilar materials such as metals, wood, ceramics and thermoset plastics.

Abstract: The invention concerns a method for preparing a particle comprising a lanthanide chelate, comprising polymerizing a lanthanide chelate derivative with one or more monomers, wherein the lanthanide chelate derivative has the formula M-L-Y (I), wherein Y is a lanthanide chelate; L is a linker and M is a polymerizable moiety. The invention concerns also the novel lanthanide chelate derivative M-L-Y (I). Further, the invention concerns a novel particle comprising a lanthanide chelate covalently bound to an organic polymer or copolymer via a linker.

Abstract: A process of producing particles for diagnostic reagent, including forming a matrix particle by mixing a nuclear particle having a CV value of 20% or less and a magnetic substance containing at least one of Fe2O3 and Fe3O4 and giving a shear force to the mixture to adsorb the magnetic substance on the surface of the nuclear particles; and polymerizing a polymerizable monomer in the presence of said matrix particle to form a polymer layer on the magnetic substance layer.

Abstract: A golf ball comprising a center comprising a polybutadiene having a molecular weight of greater than 200,000 and a resilience index of at least about 40; and a cover layer comprising a polyurethane composition formed from a prepolymer having no greater than 7.5 percent by weight unreacted isocyanate groups.

Abstract: This invention discloses a process for the preparation of polyethylene resins having a narrow molecular weight distribution that comprises the steps of: (i) providing a first high molecular weight metallocene-produced linear low density polyethylene (mLLDPE) resin having a density of from 0.920 to 0.940 g/cm3 and a MI2 of from 0.05 to 2 g/10 min; (ii) providing a second high density polyethylene (HDPE) prepared either with a Ziegler-Natta or with a metallocene catalyst, said polyethylene having a density ranging from 0.950 to 0.970 g/cm3 and a MI2 of from 0.5 to 10 g/10 min; (iii) physically blending together the first and second polyethylenes to form a polyethylene resin having a narrow molecular weight distribution, a density ranging from 0.940 to 0.955 g/cm3 and a MI2 of from 1 to 2 g/10 min.

Abstract: Novel copolymers, including block copolymers, which comprise: (a) a plurality of constitutional units that correspond to one or more olefin monomer species and (b) a plurality of constitutional units that correspond to one or more protected or unprotected hydroxystyrene monomer species.

Abstract: Disclosed is a process for producing branched polymers including at least 50 mol % C3–C40 olefins. The process may include: (1) feeding a first catalyst, an activator, and one or more C2–C40 olefins into a first reaction zone at a temperature of greater than 70° C. and a residence time of 120 minutes or less to produce a product; (2) feeding the product a second catalyst, and an activator into a second reaction zone at a temperature of greater than 70° C., and a residence time of 120 minutes or less. One of the catalysts should be chosen to produce a polymer having a weight average molecular weight of 100,000 or less and a crystallinity of 20% or less. The other catalyst should be chosen to producing a polymer having a weight average molecular weight of 100,000 or less and a crystallinity of 20% or more.

Abstract: The present invention relates to novel functional norbornenes as initiators for radical polymerization, its polymer and a process for producing the same. More particularly, the novel functional norbornenes can be selectively polymerized by ring-opening metathesis polymerization or radical polymerization to obtain various polynorbornene derivatives or grafted copolymer materials. The polynorbornene derivatives and grafted copolymer materials not only exhibit excellent functional properties but also enhanced physical and chemical properties after modification. The polynorbornene derivatives and grafted copolymer materials disclosed in the present invention exhibit excellent heat resistance, transparency and water resistance. The present invention also deals with a process for producing such derivatives and materials having controllable molecular weight with narrow molecular weight distribution.

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: The present invention provides a new copolymer of propylene and a conjugated diene having a carbon-carbon double bond in a side chain, wherein a molar ratio of a total of 1,2-adducts and 3,4-adducts to 1,4-adducts, derived from the conjugated diene, is 100:0. The copolymer is prepared in a process, characterized in that propylene and the conjugated diene are copolymerized in the presence of hydrogen, an organometallic compound comprising a transition metal selected from the group 4 of the periodic table, and at least one Lewis acid.

Abstract: A novel graft polymer useful in various uses that has a polyolefin backbone having polyolefin segments excellent in moldability can be obtained by homopolymerizing a novel polyolefin macromonomer or polymerizing the novel polyolefin macromonomer in the coexistence of other olefins depending on need, wherein the macromonomer has at the terminal of its polyolefin chain a vinyl group whose ?-position may be substituted, and the macromonomer can be efficiently obtained by a method, for example, successively carrying out i) a step of producing a polyolefin having a hydroxyl group at the terminal of the polyolefin chain and ii) a step of converting the terminal hydroxyl group of the polyolefin in chain into an acryloyl group, a methacryloyl group or a styryl group.

Abstract: The present invention relates to a polymerization process for the control of the microstructure of polymers and to novel copolymers. An embodiment of the present invention relates a process of polymerizing first and second monomers in the presence of a complex comprising at least one of the monomers. The presence of the complex modifies the relative reactivity, or cross propagation rate constants, of the monomers in copolymerization reactions. Embodiments of the present invention allow the synthesis of polymers with novel stereochemistry and monomer sequence distribution, for example, but not limited to, copolymers with at least one segment of alternating monomers, a controlled molecular weight and narrow molecular weight distribution, or a segment of high concentration of the first monomer.

Abstract: Processes for producing an AB block copolymer, an ABA block copolymer or a multiblock copolymer are provided, which comprises adding an alkenyl-containing polymer (I) to a living or to an atom transfer radical polymerization system or a living cationic polymerization system.

Abstract: It has been discovered that certain compounds serve as particle size regulators when employed together with peroxide initiators for the polymerization of vinylaromatic monomers in the presence of diene polymers. Suitable compounds that can control particle size include, but are not necessarily limited to, cobalt naphthenate, zinc naphthenate, iron octoate, calcium octoate, zinc octoate, zinc neodecanoate, potassium octoate, copper naphthenate, calcium versalate, and the like. Use of these metal carboxylates when vinylaromatic monomers are polymerized in the presence of polybutadienes and peroxide initiators results in reduced polybutadiene particles. Grafting and morphology characteristics may also be improved.

Abstract: A syndiotactic styrenic polymer having a narrow molecular weight distribution which is a (co)polymer comprising at least one structural unit represented by the following Formula (1): wherein C1 of a phenyl group thereof has a tacticity of 30% or more in terms of a racemic pentad determined by 13C-NMR, and Ra and m are as defined in the specification. The disclosure is also directed to a block copolymer comprising the above polymer as one segment, to a block graft polymer prepared by modifying one block of the above polymer with a nitrogen-containing aromatic polymer, and to a process for preparing a syndiotactic styrenic polymer in which a styrenic monomer is polymerized in the presence of a catalyst comprising a reaction product of a transition metal compound and at least one co-catalyst selected from organic aluminunoxy compounds.

Abstract: A two-part acrylic structural adhesive comprises a first package containing from about 10 to about 90 percent by weight of at least one ethylenic unsaturated methacrylic ester selected from the group consisting of 1) an alkyl mono-, di- or tetra-substituted cyclohexyl methacrylate, wherein the substitutions occur in either the 3, 4, and/or 5 ring positions, and 2) a linear or branched C4–C10 alkyl methacrylate; from about 10 to about 80 percent by weight of a toughener, and an adhesion promoter; and a second package containing a bonding activator, and, optionally, an epoxy resin.

Abstract: A method of room temperature synthesis of magnetic metal oxide nanoclusters within a diblock copolymer matrix includes the step of synthesizing, by ring opening metathesis polymerization technique, a diblock copolymer having a repeat unit ratio m/n, introducing, at room temperature, one or several metal containing precursors into the one block of the diblock copolymer, and processing the metal containing diblock copolymer by wet chemical technique to form nanoclusters of the metal(s) oxide within the diblock copolymer matrix. Specific reaction for synthesis of CoFe3O4 and Co3O4 nanoclusters within diblock copolymers, such as [NOR]m/[NORCOOH]n and [NOR]m/[CO(bTAN)]n, respectively is used in the method of the present invention.

Abstract: Provided are a variety of monomers suitable of producing photosensitive polymers, that are in turn, useful in photoresist compositions, through radical (cationic) polymerization including at least one multi-ring alkenyl ethers and one ?-fluorinated acrylate. The resulting photoresist compositions exhibit both acceptable resistance to dry etching processing and light transmittance suitable for use with various light sources such as KrF excimer lasers, ArF excimer lasers or F2 excimer lasers, in a photolithography process to produce fine photoresist patterns. In addition to the multi-ring alkenyl ethers and ?-fluorinated acrylates, additional monomers comprising one or more cyclic aliphatic and heterocyclic compounds, both unsubstituted and substituted, in particular dihydropyrans, may be incorporated into the photosensitive polymers.

Abstract: Additives for hydrogenated resins obtainable by using the following components: a) bifunctional perfluoropolyethers having a —COOR end group, optionally in admixture with monofunctional perfluoropolyethers having a —COOR end group, b) mono, bi or polyfunctional hydrogenated monomers having functional groups able to react with the —COOR end groups of compound a); c) polyolefins having functional groups able to react with the block oligomer/polymer obtained by reaction of a) with b), preferably said functional groups being obtained by grafting with maleic anhydride; reacting in a first step a) with b), until disappearance of the —COOR group of component a), and in a second step the product obtained from the reaction of a) with b) with the functionalized polyolefins c).

Abstract: The invention relates to a process for the preparation of 15-pentadecanolide by hydrogenating 15-pentadecenolide and to its use.

Abstract: The invention relates to olefin branched macromonomers, olefin graft copolymers and olefin resin compositions having the advantage of good compatibility with polyolefin resins and good moldability and workability. The olefin branched macromonomer satisfies the following (a) and (b): (a) its weight-average molecular weight (Mw) measured through gel permeation chromatography (GPC) falls between 400 and 200000; (b) its vinyl content is at least 70 mol % of all the unsaturated groups in the macromonomer.

Abstract: This invention provides a production method of a vinyl polymer having a functional group at a molecular chain terminus which comprises adding a compound (I) having a functional group and an internal alkenyl group or conjugated polyene compound (II) in the living radical polymerization of a radical-polymerizable vinyl monomer. The present invention relates to a vinyl polymer having a functional group at a molecular terminus, a production method of the same and a curable composition containing said polymer.

Abstract: The present invention relates to nitrile rubber polymers having lower molecular weights and narrower molecular weight distributions than those known in the art. The present invention also relates to a process for the manufacture of said nitrile rubber and the use of said nitrile rubber for the manufacture of shaped articles.

Abstract: In accordance with the present invention, there are provided film adhesive compositions comprising at least one macromonomer having at least one unit of ethylenic unsaturation, at least one thermoplastic elastomer co-curable with the macromonomer, and at least one cure initiator, and methods for use thereof. Invention compositions are useful as adhesives in the microelectronics industry. In particular, invention film adhesives may be used to produce microelectronic assemblies with very thin bond lines without compromising adhesive strength.

Abstract: A novel polyolefin graft copolymer prepared by graft-copolymerizing an olefin monomer with a (meth)acryl macromonomer or an isobutylene macromonomer in the presence of a coordination polymerization catalyst based on a late transition metal complex and a method for making the novel polyolefin graft copolymer are provided.

Abstract: A composition is disclosed having a density of at least 950 kg/m3, a fluidity index MI5 of 0.05 to 2 g/10 min and a content of alpha-olefin containing from 4 to 10 carbon atoms of from 0.15 to 1 mole %, comprising:—from 53 to 63% by weight based on the total weight of the composition of an ethylene polymer fraction (A) having a fluidity index MI2 of at least 100 g/10 min, a density of at least 969 kg/m3 and a molecular weight distribution Mw/Mn greater than 4, and −37 to 47% by weight with based on the total weight of the composition of a copolymer fraction (B) of ethylene and from 0.32 to 2.7 mole % of at least one alpha-olefin containing from 4 to 10 carbon atoms, a fluidity index MI5 Of 0.001 to 0.5 g/10 min, a density of no more than 930 kg/m3 and a molecular weight distribution Mw/Mn, greater than 4,—wherein the ratio of the MI2 of fraction (A) to the MI5 of fraction (B) is greater than 2000.

Abstract: A highly uniform vinyl compound polymer-cross-copolymerized olefin/styrene/diene copolymer excellent in processability, mechanical properties, high temperature properties, compatibility and transparency, and its composition and a process for its production, are provided. This copolymer is a crossed polymer obtained by cross-copolymerizing an olefin/styrene/diene copolymer having a styrene content of from 0.03 mol % to 96 mol %, a diene content of from 0.0001 mol % to 3 mol % and the rest being an olefin, with an olefin/aromatic vinyl compound copolymer.

Abstract: A two-part adhesive systems exhibiting improved fixture and open times are disclosed. In one embodiment, the system includes (a) an adhesive part being a mixture formed from (I) an ethylenically unsaturated monomer, (II) a metal molybdate, (III) a metal salt of an ethylenically unsaturated carboxylic acid in an amount less than 3 weight percent, and (IV) an ethylenically unsaturated carboxylic acid, and (b) an activator part which includes a free radical generator. In another embodiment, the system includes the above-described adhesive part substantially free of a metal salt of an ethylenically unsaturated carboxylic acid. Curable adhesives and laminates prepared with the two-part system are also disclosed.

Abstract: A process of producing particles for diagnostic reagent, including a step of polymerizing a polymerizable monomer in the presence of a matrix particle having a magnetic substance layer containing at least one of Fe2O3 and Fe3O4 on the surface thereof and having a mean particle size of 0.4-200 &mgr;m to form a polymer layer on the magnetic substance layer.

Abstract: Disclosed is a rubber composition for forming a core of a solid golf ball, the composition containing a base rubber (A); a filler (B); an organic peroxide (C); and a dry blend and/or a solvent slurry blend (D) of an unsaturated carboxylic acid metallic salt and a metal-containing organic sulfur compound represented by the following formula (1): (wherein X represents a halogen atom, each of m and n represents an integer of 0 to 5 inclusive, and M represents a divalent metallic atom). The rubber composition exhibits high curing rate, and can be cured within shorter time, whereby productivity of a core can be improved.

Abstract: Provided are a variety of monomers suitable of producing photosensitive polymers, that are in turn, useful in photoresist compositions, through radical (cationic) polymerization including at least one multi-ring alkenyl ethers and one &agr;-fluorinated acrylate. The resulting photoresist compositions exhibit both acceptable resistance to dry etching processing and light transmittance suitable for use with various light sources such as KrF excimer lasers, ArF excimer lasers or F2 excimer lasers, in a photolithography process to produce fine photoresist patterns. In addition to the multi-ring alkenyl ethers and &agr;-fluorinated acrylates, additional monomers comprising one or more cyclic aliphatic and heterocyclic compounds, both unsubstituted and substituted, in particular dihydropyrans, may be incorporated into the photosensitive polymers.

Abstract: A circuit-connecting material which is interposed between circuit electrodes facing each other and electrically connects the electrodes in the pressing direction by pressing the facing electrodes against each other; the circuit-connecting material comprising as essential components (1) a curing agent capable of generating free radicals upon heating, (2) hydroxyl-group-containing resin having a molecular weight of 10,000 or more and (3) a radical-polymerizable substance. Also provided are a circuit terminal connected structure and a circuit terminal connecting method which make use of such a material.

Abstract: The invention relates to novel propylene polymers with improved properties especially with improved stiffness and impact strength comprising propylene homopolymers or propylene block copolymers with 90.0 to 99.9 wt % propylene and 0.1 to 10 wt % &agr;-olefins with 2 or 4 to 18 carbon atoms, or mixtures thereof, wherein the propylene homopolymers or propylene block copolymers are &bgr;-nucleated propylene polymers, whereby the &bgr;-nucleated propylene homopolymers have an IR&tgr;≧0.98, a tensile modulus ≧1500 MPa at +23° C. and a Charpy impact strength, ≧3 kJ/m2 at −20° C. using notched test specimens, and the &bgr;-nucleated propylene block copolymers are polymers having an IR&tgr; of the propylene homopolymer block of ≧0.98, a tensile modulus ≧1100 Mpa at +23° C. and a Charpy impact strength of ≧6 kJ/m2 at −20° C. using notched test specimens.

Abstract: A polyolefin product is provided which comprises a branched olefin copolymer having an syndiotactic polypropylene backbone, polyethylene branches and, optionally, one or more comonomers. The total comonomer content of the branched olefin copolymer is from 0 to 20 mole percent. Also, the mass ratio of the syndiotactic polypropylene to the polyethylene ranges from 99.9:0.1 to 50:50.

Abstract: It has been discovered that certain compounds serve as polymerization accelerators when employed together with peroxide initiators for the polymerization of vinylaromatic monomers. Suitable accelerators that increase the rate of decomposition of the peroxide initiator include, but are not necessarily limited to, hydroperoxides and/or metallic salts. Representative examples of suitable hydroperoxide accelerators include t-butyl hydroperoxide (TBH), cumyl hydroperoxide, and p-isopropyl cumyl hydroperoxide, whereas suitable metallic salt accelerators include cobalt naphthenate and cobalt acetoacetonate. Use of these accelerators when vinylaromatic monomers are polymerized in the presence of polybutadienes and peroxide initiators results in an increase in grafting as compared with similar copolymers made without the accelerator.

Abstract: The present invention relates to a styrene copolymer and the method of preparing the same through the steps described in the following: a step of making a living polymer with an active anion by polymerizing an anionically polymerizable monomer in a non polar solvent in the presence of alkyllithum catalyst; a step of preparing a macro monomer by reacting the abovementioned living polymer with a terminal modifier represented by the structure of formula 1; and a step of copolymerizing the above macro monomer with styrene monomer with transition catalyst and co-catalyst.

Abstract: The present invention provides highly branched block copolymers comprising branched soft segments with a low glass-transition temperature (Tg) and hard segments with a high Tg or crystalline melting point that exhibit thermoplastic elastomeric properties. More particularly the invention provides a highly branched block copolymer of a polyisoolefin and a polymonovinylidene arene characterized by having thermoplastic elastomeric properties wherein the aforesaid block copolymer comprises a highly branched polyisoolefin block and some of the branches of the aforesaid polyisoolefin block terminate in polymonovinylidene arene endblocks.

Abstract: A process for producing a polyolefin-based resin composition comprises, in the first polymerization stage, polymerizing an &agr;-olefin having 4 to 20 carbon atoms, a styrene or a cyclic olefin in the presence of a specific catalyst and, in the second polymerization stage, copolymerizing the obtained polymer with an &agr;-olefin having 2 to 20 carbon atoms, a styrene or a cyclic olefin in the presence of a polyene. A polypropylene composition has a branching parameter a and a branching index g in specific ranges. The curve showing the change in viscosity under elongation with time, the degradation parameter D or the content of a high molecular weight component is specified. The polyolefin-based resin composition exhibits excellent uniformity and improved workability in melting due to improved tension in melted condition. The polypropylene composition exhibits excellent melting elasticity and secondary workability and provides foamed molded articles, sheets and blow molded articles.