186 results about "Natta" patented technology

Fibers comprising a propylene homopolymer or a copolymer of propylene and at least one of ethylene and one or more unsaturated comonomers exhibit desirable properties. The homopolymers are characterized as having ¹³C NMR peaks corresponding to a regio-error at about 14.6 and about 15.7 ppm, the peaks of about equal intensity. The copolymers are characterized as (A) comprising at least about 60 weight percent (wt %) of units derived from propylene, and (B) having at least one of the following properties: (i) ¹³C NMR peaks corresponding to a regio-error at about 14.6 and about 15.7 ppm, the peaks of about equal intensity, (ii) a B-value greater than about 1.4 when the comonomer content of the copolymer is at least about 3 wt %, (iii) a skewness index, S_ix, greater than about −1.20, (iv) a DSC curve with a T_me that remains essentially the same and a T_max that decreases as the amount of comonomer in the copolymer is increased, and (v) an X-ray diffraction pattern that reports more gamma-form crystals than a comparable copolymer prepared with a Ziegler-Natta (Z-N) catalyst.

The present invention relates to propylene polymerization process in a bulk loop reactor, and particularly to propylene polymerization process for polymerizing commercial quantities of polypropylene in a bulk loop reactor by sequentially introducing Ziegler-Natta and metallocene catalyst systems into the bulk loop reactor. In one embodiment, separate catalyst mixing systems are used to introduce a quantity of metallocene catalyst and Ziegler-Natta catalyst into the bulk loop reactor. The frequency rate at which the quantity of metallocene catalyst is introduced into the bulk loop reactor may be higher than the frequency rate at which the quantity of Ziegler-Natta catalyst is introduced. In another embodiment, a method of polymerizing propylene in a bulk loop reactor is provided which includes contacting a quantity of supported metallocene catalyst with a first quantity of scavenger, such as TEAL and or TIBAL, prior to injecting the supported metallocene catalyst into the bulk loop reactor and contacting a quantity of Ziegler-Natta catalyst system with a second quantity of scavenger prior to injecting the Ziegler-Natta catalyst system into the bulk loop reactor, wherein the second quantity of scavenger is greater that the first quantity of scavenger. In another embodiment, a method of contacting a flow of metallocene with a flow of propylene is provided. This method includes directing the flow of metallocene towards a junction, directing the flow of propylene towards the junction and maintaining a portion of the flow of metallocene separate from a portion of the flow propylene within a portion of the junction downstream of the flow of propylene into the junction. In another embodiment, a method of introducing a quantity of antifouling agent into a catalyst mixing system is provided. In this embodiment a portion of the antifouling agent is introduced at or downstream of a point of contact of a stream of propylene with a stream of catalyst. The antifouling agent may be a member, alone or in combination with other members, selected from the group consisting of Stadis 450 Conductivity Improver, Synperonic antifouling agent, and Pluronic antifouling agent.

A method for making a Ziegler-Natta catalyst support includes the steps of contacting a fumed silica with a surface modifying agent such as a compound having the formula RMgX MgR′R″ wherein R, R′ and R″ are each individually a moiety selected from an alkyl group, cycloalkyl, aryl or alkaryl group, and X is a halogen selected from the group consisting of chlorine, bromine and iodine, to provide a pretreated silica seeding agent. The pretreated silica seeding agent is then dispersed in a non-aqueous liquid magnesium halide/alkanol complex, and the magnesium halide is crystallized onto the silica particles to form-catalyst support particles especially suitable for Ziegler-Natta catalysts.

Processes for transitioning among polymerization catalyst systems, preferably catalyst systems that are incompatible with each other. In particular, the processes relate to transitioning from olefin polymerizations utilizing metallocene catalyst systems to olefin polymerizations utilizing traditional Ziegler-Natta catalyst systems.

A process for producing an olefin-based polymer, said process comprising polymerizing at least one monomer, in the gas phase, or in a slurry process, in the presence of at least the following components:

• • A) at least one catalyst;
  • B) at least one cocatalyst;
  • C) a composition comprising at least one compound selected from formula (I), and/or at least one compound selected from formula (II):

(R1CO₂)₂AlOH   (I),

(R2)_xN(R3OH)_y   (II);

• • wherein R1 is a hydrocarbon radical containing from 13 to 25 carbons;
  • R2 is a hydrocarbon radical containing from 14 to 26 carbons;
  • R3 is a hydrocarbon radical containing from 1 to 4 carbons; and
  • x+y=3, and x has a value of 1 or 2.

A process for producing an olefin-based polymer, said process comprising polymerizing at least one monomer in the presence of at least the following components:

• • A) a Ziegler Natta type catalyst comprising at least two transition metals;
  • B) a trialkylaluminum compound;
  • C) optionally a composition comprising at least one compound selected from formula (I), and/or at least one compound selected from formula (II):

(R1CO₂)₂AlOH   (I),

(R2)_xN(R3OH)_y   (II);

• • wherein R1 is a hydrocarbon radical containing from 13 to 25 carbons;
  • R2 is a hydrocarbon radical containing from 14 to 26 carbons;
  • R3 is a hydrocarbon radical containing from 1 to 4 carbons; and
  • x+y=3, and x has a value of 1 or 2.

The invention relates to polypropylene with narrow distribution of molecular weight and a preparation method, and especially relates to a propylene polymer with narrow distribution of molecular weight by employing a Ziegler-Natta catalyst through direct reactor polymerization. The polymer has high and adjustable isotacticity, the molecular weight distribution is narrow, and the high-molecular trailing index is high. propylene is not contained in a locational isomeric structure, the melting point and crystallization temperature are high, compared with a traditional degradation method for producing the polypropylene with narrow distribution, the polypropylene with narrow distribution of molecular weight has the advantages of economy, energy saving and environmental protection. The product is especially suitable for the fields with high fluidity requirement such as spinning, injecting by a thin wall, casting the transparent material. In addition, due to characteristic of narrow distribution of molecular weight, the polymer has a certain advantage on transparency application aspect.

The present invention is a high barrier multilayer film particularly suitable for packaging. The high barrier multilayer film is a film including (a) a core substrate layer having an isotactic polypropylene produced from Ziegler-Natta catalysts, and (b) an adjacent layer on at least one surface of the core substrate layer, wherein the adjacent layer (b) comprises an isotactic polypropylene produced from metallocene catalysts; or the high barrier multilayer film includes (a') a core substrate layer having an isotactic polypropylene produced from metallocene catalysts, and (b') an adjacent layer on at east one surface of the core substrate layer, wherein the adjacent layer (b') comprises an isotactic polypropylene produced from Ziegler-Natta catalysts.

Novel catalyst compositions comprising three or more transition metals are effective in increasing catalyst efficiency, reducing polydispersity, and increasing uniformity in molecular weight distribution when used in olefin, and particularly, linear low density polyethylene (LLDPE), polymerizations. The resulting polymers may be used to form differentiated products including, for example, films that may exhibit improved optical and mechanical properties.

A combinatorial method for identifying a catalyst composition for use in the heterogeneous Ziegler-Natta addition polymerization of an olefin monomer, said catalyst composition comprising a compound of a metal of Group 2 of the Periodic Table of the Elements.