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EP-4735488-A1 - MULTI STAGE PROCESS FOR PRODUCING ETHYLENE-BASED POLYMER WITH (ULTRA) HIGH MOLECULAR WEIGHT POLYETHYLENE COMPONENT

EP4735488A1EP 4735488 A1EP4735488 A1EP 4735488A1EP-4735488-A1

Abstract

Embodiments of methods of producing ethylene-based polymers comprising first and second polymer fractions include reacting ethylene monomer and optionally C 3 -C 12 α-olefin comonomer in solvent in the presence of a reaction A catalyst in at least one tubular reactor to produce the first polymer fraction reaching an exit temperature of this reaction zone below 160 °C, wherein the weight averaged molecular weight (Mw) of this first polymer fraction is larger than 500,000 g/mol; introducing the first polymer fraction, ethylene monomer, optionally C 3 -C 12 α-olefin comonomer, solvent, at least two reaction B catalysts, and a shuttling agent to at least one agitated solution polymerization reactor; and reacting the ethylene monomer and optionally C 3 -C 12 α-olefin comonomer in solvent in the presence of the at least two reaction B catalysts, and a shuttling agent in the at least one agitated solution polymerization reactor to produce a second polymer fraction.

Inventors

  • WEVERS, RONALD

Assignees

  • Dow Global Technologies LLC

Dates

Publication Date
20260506
Application Date
20230926

Claims (11)

  1. 1. A method of producing ethylene-based polymer comprising first and second polymer fractions comprises: reacting ethylene monomer and optionally C3-C12 a-olefin comonomer in solvent in the presence of a reaction A catalyst in at least one tubular reactor to produce the first polymer fraction reaching an exit temperature of this reaction zone below 160 °C, wherein the weight averaged molecular weight (Mw) of this first polymer fraction is larger than 500,000 g/mol; introducing the first polymer fraction, ethylene monomer, optionally C3-C12 a-olefin comonomer, solvent, at least two reaction B catalysts, and a shuttling agent to at least one agitated solution polymerization reactor; reacting the ethylene monomer and optionally C3-C12 a-olefin comonomer in solvent in the presence of the at least two reaction B catalysts and the shuttling agent in the at least one agitated solution polymerization reactor to produce a second polymer fraction; and outputting effluent from the at least one agitated solution polymerization reactor, wherein the effluent comprises the ethylene-based polymer having the first and second polymer fractions, unreacted ethylene monomer, and optionally unreacted C3-C12 a-olefin comonomer, wherein the ethylene-based polymer comprises 0.1 to 15 wt.% of the first polymer fraction and more than 70 wt.% of the second polymer fraction, and wherein the ethylene-based polymer has a melt index (I2) from 0.2 g/10 mins to 20 g/10 mins., a density between 0.880 g/cc to 0.908 g/cc and has an Mz/Mw greater than the Mw/Mn.
  2. 2. The method of claim 1, wherein the ethylene based polymer has a melt flow ratio I2/I10 of at least 9.
  3. 3. The method of any preceding claim, further comprising reacting the effluent of the at least one agitated solution polymerization reactor in the presence of a reaction C catalyst in a mixer downstream of the at least one agitated solution polymerization reactor wherein the reaction C catalyst facilitates further reaction of the unreacted ethylene monomer and optionally any unreacted C3-C12 a-olefm comonomer to produce a third polymer fraction having a density and melt index (I2) different from the second polymer fraction.
  4. 4. The method of claims 3, further comprising introducing a mixer effluent from the mixer to a tubular polymerization reactor, wherein the mixer effluent comprises the ethylene-based polymer having the first, second, and third polymer fractions.
  5. 5. The method of any preceding claim, wherein the at least one tubular reactor is a plug flow reactor and the at least one agitated solution polymerization reactor comprises at least one continuous stirred tank reactor (CSTR), at least one loop reactor, or combinations thereof.
  6. 6. The method of any preceding claim, wherein: the ethylene monomer and C3-C12 a-olefm comonomer have a residence time Ri in the at least one tubular reactor; the ethylene monomer and optionally C3-C12 a-olefin comonomer have a residence time R2 in the at least one agitated solution polymerization reactor; and a ratio of R1/R2 is from 0.1 to 0.5.
  7. 7. The method of any preceding claim, wherein the at least one agitated solution polymerization reactor comprises an exit temperature of at least 150 °C.
  8. 8. The method of any preceding claim, wherein: the reaction A catalyst in the at least one tubular reactor comprises a molecular catalyst; the at least two reaction B catalysts in the at least one agitated solution polymerization reactor each comprise a molecular catalyst; and the shuttling agent is diethyl zinc.
  9. 9. The method of any preceding claim, wherein the ethylene -based polymer comprises from 2 to 8 wt.% of the first polymer fraction and the ethylene-based polymer has a melt index (I2) from 0.5 g/10 min to 5 g/10 min.
  10. 10. An elastic article comprising a polymer having a melt index (I2) from 0.2 g/10 mins to 20 g/10 mins, a density between 0.880 g/cc to 0.908 g/cc and has an Mz/Mw greater than the Mw/Mn, wherein the polymer has been oriented to at least 4 times its original dimensions.
  11. 11. The elastic article of claim 10, wherein the polymer has been allowed to relax after having been oriented.

Description

MULTI STAGE PROCESS FOR PRODUCING ETHYLENE -BASED POLYMER WITH (ULTRA) HIGH MOLECULAR WEIGHT POLYETHYLENE COMPONENT CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application Serial No. 63/510,435 filed June 27, 2023, the entire disclosure of which is hereby incorporated herein by reference. TECHNICAL FIELD [0002] The present specification generally relates to processes of making ethylene-based polymers, and in particular, methods of making ethylene based polymer comprising an ultrahigh molecular weight component. BACKGROUND [0003] To improve toughness and processability of ethylene-based polymer (e.g., LLDPE), (ultra) high molecular weight polyethylene (UHWMPE) material may be added to ethylene -based polymer. Currently, UHMWPE is produced using heterogenous catalysts, in slurry phase or gas phase. Adding UHMWPE conventionally via blending results in relatively large UHMWPE particles, consisting of highly entangled macromolecules. Incorporation of these entangled clusters of UHMWPE in the molecular structure of an ethylene-based polymer is difficult because of the extreme viscosity differences. Specifically, the UHMWPE may have a melt index (I2) of less than 0.01, whereas the bulk resin (e.g., LLDPE) may have a melt index at least a hundred times greater than that. Thus, there is a continual need for processes to better incorporate UHMWPE into ethylene-based polymers, such as LLDPE. SUMMARY [0004] Embodiments of the present disclosure meet this need for improved UHWMPE incorporation by producing UHMWPE in solution at low to moderate reaction temperatures, wherein the catalyst used is not for particle formation (as in slurry or gas phase technology), but aims at producing UHMWPE chains which are evenly dispersed either dissolved or as fine mist (very fine phase separated) in the solvent. In the subsequent solution process conditions, the dissolved or dispersed UHMWPE will be solution blended with the ethylene-based polymer. This results in a highly dis-entangled UHMWPE fraction in solution, which is easily incorporated in the downstream solution reactor used to produce the ethylene-based polymer. [0005] According to one embodiment, a method of producing ethylene -based polymer comprising first and second polymer fractions is provided. The method comprising reacting ethylene monomer and optionally C3-C12 a-olefin comonomer in solvent in the presence of a reaction A catalyst in at least one tubular reactor to produce the first polymer fraction reaching an exit temperature of this reaction zone below 160 °C, wherein the weight averaged molecular weight (Mw) of this first polymer fraction is larger than 500,000 g/mol; introducing the first polymer fraction, ethylene monomer, C3-C12 a-olefin comonomer, solvent, at least two reaction B catalysts, and a shuttling agent to at least one agitated solution polymerization reactor; reacting the ethylene monomer and C3-C12 a-olefin comonomer in solvent in the presence of the at least two reaction B catalysts and the shuttling agent in the at least one agitated solution polymerization reactor to produce a second polymer fraction; and outputting effluent from the agitated solution polymerization reactor, wherein the effluent comprises the ethylene-based polymer having the first and second polymer fractions, unreacted ethylene monomer, and optionally unreacted C3-C12 a-olefin comonomer, wherein the ethylene -based polymer comprises 0.1 to 15 wt.% of the first polymer fraction and more than 70 wt.% of the second polymer fraction, and wherein the ethylenebased polymer has a melt index (I2) from 0.2 g/10 mins to 20 g/10 mins., a density between 0.880 g/cc to 0.908 g/cc and has an Mz/Mw greater than the Mw/Mn. [0006] According to one embodiment, an elastic article may comprise a polymer having a melt index (I2) from 0.2 g/10 mins to 20 g/10 mins., a density between 0.880 g/cc to 0.908 g/cc and Mz/Mw greater than the Mw/Mn, wherein the polymer has been oriented to at least 4 times its original dimensions. [0007] Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the drawings, the detailed description which follows and the claims. BRIEF DESCRIPTION OF THE DRAWINGS [0008] FIG. 1 is a schematic view of the present process according to one or more embodiments of the present disclosure; [0009] FIG. 2 is another schematic view of the present process according to one or more embodiments of the present disclosure; and [0010] FIG. 3 is yet another schematic view of the present process according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION [0011] Specific embodiments of the present application will now be described. The disclosure may, however, be embodied in different forms and should not be constr