Abstract: A process for producing polypropylene is provided which comprises polymerizing propylene in multiple stages, in the presence of a catalyst which is prepared by reacting a first organoaluminum compound (i), or a reaction product (vi) formed between the first organoaluminum compound (i) and an electron donor (a), with titanium tetrachloride (c) to obtain a first solid product (ii), reacting the resulting first solid product (ii) with the electron donor (a) and an electron acceptor (b) to obtain a second solid product (iii), and combining the resulting second solid product (iii) with a second organoaluminum compound (iv) and an aromatic carboxylic acid ester (v) at a molar ratio of the aromatic carboxylic acid ester to the second solid product (v/iii molar ratio) of from 0.1 to 10.

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 highly crystalline polypropylene is provided having:(A) (i) a melt flow rate (MFR) in the range of 0.1-200 g/10 minutes 230.degree. C. and (ii) an absorbance ratio determined by infrared absorption spectroscopy, IR-.rho., of wave-number 997 cm.sup.-1, A.sub.997, to wave-number 973 cm.sup.-1, A.sub.973, which satisfies the equation:IR-.tau..gtoreq.0.0203 log MFR+0.950; and(B) (i) an IR-.tau. value of at least 0.97 of a component deposited initially in an amount of 2 to 3% by weight from a dilute, slowly cooled and stirred xylene solution of the polypropylene and (ii) a ratio of the weight average molecular weight of the deposited component (M.sub.w1) to that of the polypropylene (M.sub.w0), M.sub.w1 /M.sub.w0, of at least 3.

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 process for continuously producing a propylene-ethylene block copolymer having well-balanced qualities such as high-impact properties, stiffness, processability, etc., with a good productivity, through two polymerization stages using a stereoregular catalyst comprising a Ti-containing solid catalyst and an organoaluminum compound, is provided, which process is characterized in that at the first stage, propylene is mainly fed into two or more polymerization vessels connected in series, to produce 60 to 95% by weight of the total polymerization quantity, and at the second stage, a specified quantity of a glycol ether is added to the polymerization reaction mixture obtained above and ethylene is fed in a relatively large quantity into one or more polymerization vessels, to produce 5 to 40% by weight of the total polymerization quantity.

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 high-rigidity, whitening-resistant ethylene-propylene copolymer is provided, which is obtained by copolymerizing propylene with ethylene at three successive stages wherein at the respective first, second and third stages, a copolymer fraction having a specified ethylene content is formed in a specified amount based on the total polymerization amount, in the presence of a catalyst obtained by reacting an organoaluminum compound (L) or a reaction product thereof with an electron donor (E) with TiCl.sub.4 ; reacting the resulting solid product (I) with an (E) and an electron acceptor; and combining the resulting solid product (II) with an (L) and an aromatic carboxylic acid ester (R), the molar ratio of (R) to (II) being specified, and in the presence of hydrogen.

Abstract: A propylene-ethylene block copolymer from which molded products having high rigidity and superior high-impact properties can be prepared even without adding any particular additive, is provided, which copolymer is obtained by (i) polymerizing propylene in 70 to 95 weight % based on the total polymerized amount, using a catalyst obtained by reacting an organoaluminum compound (I) or a reaction product of (I) with an electron donor (A), with TiCl.sub.4, further reacting the resulting solid product (II) with (A) and an electron acceptor (B), and combining the resulting solid product (III) with an organoaluminum compound (IV) and an aromatic carboxylic acid ester (V), the molar ratio of (V) to (III) being 0.1 to 10.0, and then (ii) polymerizing ethylene or ethylene and propylene in 30 to 5 weight % based on the total polymerized amount, at one or more stages, using the same catalyst as above, the ethylene content being 3 to 20 weight % based on the total polymerized amount.

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: A polypropylene resin from which high-rigidity molded products can be produced even when no particular additive is added, is provided, which resin has a melt rate of 0.1 to 100, a density of 0.905 to 0.936, and a boiling n-heptane-insoluble part whose isotactic pentad ratio (P.sub.o) is 0.975 to 0.995, and whose pentad ratio (P.sub.2) having two different kinds of configurations of 0.002 to 0.000%, and preferably has a melting point of 165.degree. to 170.degree. C. as measured by differential scanning calorimetry.

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.

Abstract: A process for producing terpolymers of propylene (as a main monomer), ethylene and another .alpha.-olefin having superior and well-balanced physical properties, almost without forming soluble polymer is provided.This process is characterized by preliminarily activating a catalyst consisting of a titanium trichloride composition and a specified organoaluminum halide, with a small amount of an .alpha.-olefin of 2 to 12 carbon atoms, a trialkylaluminum and an aromatic ester, and copolymerizing specified amounts of propylene, ethylene and an .alpha.-olefin of 4 to 12 carbon atoms in the presence of the preliminarily activated catalyst obtained above.

Abstract: A method for producing crystalline copolymers of propylene (major component), ethylene and an .alpha.-olefin having 4 to 12 carbon atoms, superior in any of various practical physical properties such as cold-resistance, transparency, heat-seal temperature, percentage shrinkage, etc. is provided, wherein a catalyst solution obtained by mixing together a titanium trichloride composition (obtained by mixing and milling a titanium trichloride with a mixed reaction product of TiCl.sub.4 with an ether), a dialkylaluminum halide, an electron-donor compound and an inert solvent, is activated in advance of copolymerization, by feeding propylene into the solution under specified feeding conditions, and copolymerization is carried out by feeding propylene and said .alpha.-olefin simultaneously and continuously, while feeding ethylene intermittently into the gas phase part of the polymerization zone containing the solution.

Abstract: A process for producing a modified polypropylene by copolymerizing propylene with ethylene in the presence of a Ziegler-Natta catalyst is provided.This process consists of the following three steps:a first step of carrying out polymerization so as to give a propylene polymer corresponding to 75-90% by weight based on a final modified polypropylene and having an ethylene content of 2% by weight or lower,a second step of preparing an ethylene-propylene random copolymer (A) having an intrinsic viscosity of 12 dl/g or higher and an ethylene content of 50-95% by weight; anda third step of preparing an ethylene-propylene random copolymer (B) having an intrinsic viscosity of 9.5 dl/g or lower and an ethylene content of 40-90% by weight,the proportion of said (A) in the total amount of said (A) and (B) being adjusted to 4-30% by weight. In this process, it is possible to prepare said (B) in the second step and then prepare said (A) in the third step.