Abstract: A propylene polymer composition of high melt tension, which is especially favorable for foam moldings of uniform thickness, and foam moldings thereof having a uniform thickness, are obtained by melt-kneading a polymer mixture of a specific ethylene polymer (A) and a specific olefin multi-stage polymer (B) to satisfy the following formula: Log(MS)>0.91−0.

Abstract: A propylene polymer composition of high melt tension, which is especially favorable for foam moldings of uniform thickness, and its foam moldings of uniform thickness are obtained by melt-kneading a polymer mixture of a specific ethylene polymer (A) and a specific olefin multi-stage polymer (B) to satisfy the following formula:

Abstract: An object of this invention is to provide a polypropylene/propylene-ethylene copolymer composition having an excellent balance among rigidity, toughness, impact resistance, etc. This invention provides a polypropylene/propylene-ethylene copolymer composition having a melt flow rate of from 1 to 80 g/10 min obtained by producing a specific propylene polymer in an amount of from 60 to 95% by weight based on the total amount of the composition to be finally obtained and subsequently producing in a second stage (polymerization step (II)) a specific propylene-ethylene copolymer in an amount of from 5 to 40% by weight based on the total amount of the composition to be finally obtained. A process for producing the composition is also provided.

Abstract: A continuous process for preparation of propylene-ethylene block copolymer suitable for moldings with high rigidity and high impact resistance are provided, which process is a continuous process for preparation of highly rigid propylene-ethylene block copolymers, wherein propylene and ethylene are polymerized in the specified 2 steps with use of a catalyst system comprising (A) a solid catalyst component containing Ti, Mg, halogen and polyvalent carboxylic ester, (B) an organic aluminium compound, as well as (C) an organic silicon compound expressed by the general formula R.sup.4.sub.x R.sup.5.sub.y Si(OR.sup.6).sub.z (wherein, x+y+z=4), and wherein the ratio between the maximum value and the minimum value of MFR(l)) is0.1.ltoreq.Log(MFR(h)/MFR(l)).ltoreq.1,and the ratio between the average MFR(i) and MFR(ii) in the subsequent polymerization procedure (II) containing ethylene in a relatively large amount which is carried out by adding the glycol type compound is3.ltoreq.Log(MFR(i)/MFR(ii)).ltoreq.7.

Abstract: A propylene.ethylene block copolymer composition having a high stiffness and high-impact properties and its production process are provided,which composition is produced by using a specified Ziegler-Natta type catalyst;carrying out polymerization step (I) wherein homopolymerization of propylene is carried out by means of two or more polymerization vessels so as to afford 60 to 95% by weight based upon the total weight, and a specified range of the maximum value and the minimum value of the melt flow rates of the polymers obtained in the respective vessels; andcarrying out polymerization step (II) wherein propylene-ethylene random copolymerization is carried out by means of one or more polymerization vessels so as to afford 5 to 40% by weight based upon the total quantity,the ratio of the melt flow rate at the polymerization step (I) to the melt flow rate at the polymerization step (II) being made to fall within a specified range,whereby the resulting ethylene.

Abstract: A linear, crystalline polypropylene having a branching coefficient of substantially 1, and a specified relation between melt-tensile strength and intrinsic viscosity, a specified relation between crystallization temperature and melting point, a boiling xylene-extraction residue % of 1 wt. % or less and if necessary, a specified ratio of weight average M.W./number average M.W.; a molded product from the above polypropylene; and a process for producing a polypropylene having the above polypropylene blended with di-2-ethylhexyl peroxydicarbonate, are provided, the above polypropylenes having a very high melt-tensile strength and crystallization temperature and also superior stiffness and moldability, to thereby broaden the restricted application fields of conventional polypropylene.

Abstract: Continuous processes for producing high melting and viscoelasting polypropylene or ethylene-propylene copolymer are provided.These processes are characterized by (1) using two or more polymerizers connected in series, (2) supplying the whole amount of a catalyst and a molecular weight regulator (hydrogen) in the first tank and (3) a degasification amount of each tank in the second and subsequent tanks being 0.5 to 10 V.sub.1 /Hr (wherein V.sub.1 is a volume of the tank) calculated at 0.degree. C. and 0 Kg/cm.sup.2 G. In the process for producing the copolymer, (4) monomers having an ethylene content of 5 wt % or less are supplied in the first step. According to the processes of the present invention, polymers having a broad molecular weight distribution and good fluidity upon extrusion molding can be obtained and operational control in production is simply made.

Abstract: Continuous processes for producing high melting and viscoelasting polypropylene or ethylene-propylene copolymer are provided.These processes are characterized by (1) using two or more polymerizers connected in series, (2) supplying the whole amount of a catalyst and a molecular weight regulator (hydrogen) in the first tank and (3) a degasification amount of each tank in the second and subsequent tanks being 0.5 to 10 V.sub.1 /Hr (wherein V.sub.1 is a volume of the tank) calculated at 0.degree. C., and 0 Kg/cm.sup.2 G. In the process for producing the copolymer, (4) monomers having an ethylene content of 5 wt % or less are supplied in the first step. According to the processes of the present invention, polymers having a broad molecular weight distribution and good fluidity upon extrusion molding can be obtained and operational control in production is simply made.

Abstract: A continuous polymerization process for producing a high-melt viscoelastic ethylene-propylene copolymer by the use of Ziegler-Natta catalyst, which process make it possible to stably produce an ethylene-propylene block copolymer having superior physical properties suitable to sheet molding and blow molding and capable of producing large-size molded products is provided,which process comprises(a) feeding propylene and ethylene in a weight proportion of ethylene in the total of propylene and ethylene of 0-5% into 3 or more polymerization vessels among 4 or more polymerization vessels connected in series, to carry out continuous polymerization step (i) and successively feeding ethylene and propylene in a weight proportion of ethylene in the total of ethylene and propylene of 10-100% into one or more polymerization vessels, to carry out continuous polymerization process (ii); (b) feeding the total quantity of the catalyst only to the first polymerization vessel; (c) feeding the total quantity of hydrogen substant

Abstract: A whitening-resistant, highly melt-viscoelastic ethylene-propylene copolymer and process for producing the same are provided, which copolymer is produced by copolymerizing ethylene with propylene in the presence of a specified stereoregular catalyst and at four stages under specified conditions, the catalyst being prepared by reacting an organoaluminum compound or its reaction product with an electron donor, with TiCl.sub.4, reacting the resulting solid product with an electron donor and an electron acceptor, and combining the resulting solid product with an organo-aluminum compound and an aromatic carboxylic acid ester so as to give a specified ratio, and at the four stages, the ethylene contents in monomers fed, the proportion of polymerization amounts and the intrinsic viscosities of polymers formed being specified.

Abstract: An ethylene-propylene block copolymer capable of producing foamed shaped articles having a structure of uniform and fine foams even without adding any other resins, and a process for producing the same are provided, which copolymer consists of a propylene homopolymer portion and an ethylene-propylene (EP) copolymer portion and is characterized in that .circle.1 the former portion is obtained by polymerizing propylene at two stages so that the portion can further consist of a lower molecular weight portion and a higher molecular portion; .circle.2 between the melt flow rates of the resulting block copolymer under a specified load and five times the load, there is a specified relationship; .circle.3 the EP copolymer portion has an ethylene content of 60 to 95% by weight based on this portion; and .circle.4 the block copolymer has an ethylene content of 10 to 40% by weight based on the copolymer.

Abstract: A polypropylene (PP) having a superior post-processability and blow moldability is provided, which PP is obtained by polymerizing propylene at multiple stages using a catalyst comprising a TiCl.sub.3 composition, an organoaluminum compound and a molecular weight (M.W.) modifier, the resulting final polymer comprising a higher M.W. portion and a lower M.W. portion having a melt flow index of 0.03 to 2.0 g/10 min., and between this index and a melt flow index (10.2 kg/10 minutes, 230.degree. C.) as measured under 5 times the load applied in the measurement of the former melt flow index, there being a relationship log HMI.gtoreq.0.922 log MI+1.44, and the final polymer consisting of 40 to 60 weight % of a PP portion corresponding to the higher M.W. portion and 60 to 40 weight % of a PP portion corresponding to the lower M.W. portion.

Abstract: A superior high-rigidity and high-melt-viscoelasticity polypropylene for sheets to be post-processed and for blow molding is provided which polypropylene is produced by subjecting propylene to a multi-stage polymerization into polymer portions of two sections in the presence of a specified Ziegler Natta catalyst, the relationship between the intrinsic viscosities of the polymer portions of the respective sections being regulated within a specified range and also the amount ratio of the polymer portions of the respective sections being regulated.