摘要:
A catalyst system for the polymerization of α-olefins prepared by a process which includes catalyst activation whereby a solid transitional metal compound is contacted with an organoaluminum compound and catalyst prepolymerization whereby a premonomer is prepolymerized in the presence of the activated catalyst. High activity, low fines polymerization can be achieved if in the first step of catalyst activation a first reaction mixture is prepared by contacting the solid transitional metal compound with a first organoaluminum compound in the presence of an oil and in the second step, the first reaction mixture is contacted with a second organoaluminum compound to give a second reaction mixture, the second organoaluminum compound being the same as or different from the first organoaluminum compound.
摘要:
There is provided a process for the copolymerisation of propylene with at least one C4-20 α-olefin or C4-20 diene in a reaction medium in the presence of a catalyst system at a temperature of greater that 80° C. or at a temperature and pressure above the critical temperature and pressure of the reaction medium. Under such conditions, comonmer incorporation is higher than under standard conditions.
摘要:
A process for the production of a propylene based polymer, the process comprising the following steps: (a) a first polymerization stage comprising homopolymerizing propylene or copolymerizing propylene and at least one alpha-olefin in the presence of an alpha-olefin polymerization catalyst whereby to produce a polypropylene component; (b) a second polymerization stage comprising copolymerizing ethylene and at least one alpha-olefin in the presence of an alpha-olefin polymerization catalyst whereby to produce an ethylene/alpha-olefin copolymer component; and (c) blending the polymer components produced in steps (a) and (b) whereby to produce a polymer blend, wherein the first and second polymerization stages are effected in separate polymerization reactors connected in parallel. Also provided are polymer compositions comprising: (i) 30 to 97% by weight, based on the total weight of the polymer composition, of a propylene based polymer; and (ii) 3 to 70% by weight, preferably 5 to 20% by weight, based on the total weight of the polymer composition, of an ethylene copolymer plastomer (e.g., an ethylene-propylene plastomer) containing at least 60% by weight ethylene.
摘要:
A process for producing terpolymers of propylene, comprising a) feeding into a slurry reactor a reaction mixture containing 50-85 w-% of propylene, 1-10 w-% of ethylene, 15-40 w-% of another C4-C8 alpha-olefin, a catalyst system maintaining olefin polymerization at said temperature conditions, and optionally hydrogen, b) polymerizing said reaction mixture at a temperature of lower than 70° C. a sufficient time to obtain a propylene terpolymer amounting to 50-99 w-% of the end product, c) transferring said reaction mixture into a gas phase reactor operating at a pressure of higher than 5 bars, preferably higher than 10 bars, optionally adding 0-30 w-% of ethylene, 0-10 w-% of another C4-C8 alpha-olefin, 0-40 w-% of propylene and optionally hydrogen, and d) continuing polymerization in said gas phase reactor for obtaining a propylene terpolymer amounting to 1-50 wt-% of the end product. The terpolymer has a melting temperature a less than 135° C., preferably less than 132° C., and it can be used for manufacturing films having good sealing properties.
摘要:
The present invention relates to a polypropylene composition comprising a propylene random copolymer (A) with at least one comonomer selected from alpha-olefins with 2 or 4 to 8 carbon atoms and a nucleating agent (B), wherein the polypropylene composition has a polydispersity index (PI) of from 2.0 to 7.0, a melt flow rate MFR2 (2:16 kg, 230° C.) of from 0.05 to 1.0 g/10 min, determined according to ISO 1133 and a Charpy Notched Impact Strength at 0° C. of at least 4.0 kJ/m2, determined according to ISO 179/1eA:2000 using notched injection molded specimens, a process for producing said polypropylene composition, an article comprising said polypropylene composition and the use of said polypropylene composition for the production of an article.
摘要:
The present invention relates to a polymer composition, comprising (i) a polypropylene homopolymer, (ii) a polypropylene random copolymer, prepared by copolymerization of propylene with an olefin comonomer and having an amount of olefin comonomer units of 0.2 to 5 wt %, and (iii) an elastomeric copolymer of propylene and at least one olefin comonomer, the polymer composition having a tensile modulus, determined according to ISO 527-2/1B at 1 mm/min. and 23° C., of at least 1200 MPa.
摘要:
The present invention relates to a polymer composition, comprising (i) a polypropylene-based matrix which comprises a polypropylene random copolymer prepared by copolymerization of propylene with an olefin comonomer, wherein the amount of olefin comonomer units is within the range of (0.2) wt % to (5) wt %, based on the weight of the polypropylene-based matrix, and (ii) an elastomeric copolymer of propylene and at least one olefin comonomer, the polymer composition having a storage modulus G1 at a loss modulus G″=5 kPa of G′(5 kPa)
摘要:
The present invention relates to a process for polymerizing &agr;-olefins in at least two stages, the first stage comprising at least one bulk reactor and optionally at least one gas phase reactor for forming the &agr;-olefin polymer matrix and the second stage comprising at least one additional gas phase reactor for copolymerization of ethylene with said polymer matrix. In the second stage an antifouling composition is fed into said gas phase reactor(s) for preventing fouling in the second stage.
摘要:
A hetrophasic polypropylene copolymer having a tensile modulus of 420 Mpa or less comprising: i) a semi-crystalline propylene:ethylene: and optionally other &agr;-olefin polymer matrix; ii) an elastomeric propylene:ethylene and optionally other &agr;-olefin copolymer.
摘要:
The present invention relates to a polypropylene composition comprising a propylene random copolymer (A) with at least one comonomer selected from alpha-olefins with 2 or 4 to 8 carbon atoms and a nucleating agent (B), wherein the polypropylene composition has a polydispersity index (PI) of from 2.0 to 7.0, a melt flow rate MFR2 (2:16 kg, 230° C.) of from 0.05 to 1.0 g/10 min, determined according to ISO 1133 and a Charpy Notched Impact Strength at 0° C. of at least 4.0 kJ/m2, determined according to ISO 179/1eA:2000 using notched injection moulded specimens, a process for producing said polypropylene composition, an article comprising said polypropylene composition and the use of said polypropylene composition for the production of an article.