EP-4735489-A1 - PROCESSES FOR MAKING MULTIMODAL ETHYLENE-BASED POLYMERS

EP4735489A1EP 4735489 A1EP4735489 A1EP 4735489A1EP-4735489-A1

Abstract

Embodiments are directed to a process for producing ethylene-based polymer in a reactor system comprising a first reactor and a second reactor. The process comprises polymerizing ethylene, one or more (C 3 -C 14 )α-olefin monomers, and at least one polyene, in the presence of one multi-chain catalyst and at least one single-chain catalyst in the first reactor to produce a first reactor polyethylene product comprising long chain branching, wherein the multi-chain catalyst comprises a plurality of polymerization sites, and wherein the long-chain branching occurs by connecting two polymer chains of the multi-chain catalyst with the polyene in a concerted fashion during the polymerization; and polymerizing ethylene and one or more (C 3 -C 14 )α-olefin monomers in the absence of an initial polyene feed and in the presence of at least one single-chain catalyst in the second reactor to produce a second reactor polyethylene product, wherein the ethylene-based polymer comprises the first and second reactor polyethylene products.

Inventors

FROESE, Robert D.J.
LU, Keran
WEINHOLD, JEFFREY D.
DEN DOELDER, CORNELIS F.J.
MARTINETTI, LUCA
HOU, JIANBO
PEREIRA, Joana Amaral
BAZEN, Jan
KLOSIN, JERZY

Assignees

Dow Global Technologies LLC

Dates

Publication Date: 20260506
Application Date: 20240612

Claims (1)

85249-WO-PCT/DOW 85249 WO CLAIMS 1. A process for producing ethylene-based polymer in a reactor system comprising a first reactor and a second reactor, the process comprising: polymerizing ethylene, one or more (C 3 -C 14 )α-olefin monomers, and at least one polyene, in the presence of one multi-chain catalyst and at least one single-chain catalyst in the first reactor to produce a first reactor polyethylene product comprising long chain branching, wherein the multi-chain catalyst comprises a plurality of polymerization sites, and wherein the long-chain branching occurs by connecting two polymer chains of the multi-chain catalyst with the polyene in a concerted fashion during the polymerization; and polymerizing ethylene and one or more (C 3 -C 14 )α-olefin monomers in the absence of an initial polyene feed and in the presence of at least one single-chain catalyst in the second reactor to produce a second reactor polyethylene product, wherein the ethylene-based polymer comprises the first and second reactor polyethylene products. 2. The process of claim 1, wherein solution polymerization is conducted in the first reactor, the second reactor, or both. 3. The process of any preceding claim, wherein the at least one single-chain catalyst in the first reactor, the second reactor, or both comprises a phosphinimine catalyst. 4. The process of any preceding claim, wherein the at least one single-chain catalyst in the first reactor, the second reactor, or both comprises a bis(biphenylphenoxy)catalyst. 5. The process of any preceding claim, wherein the ethylene-based polymer comprises from 35 to 55 wt% of the first reactor polyethylene product and 45 to 65 wt% of the second reactor polyethylene product. 6. The process of any preceding claim, wherein the second reactor polyethylene product has a density of less than 0.910 g/cc, a melt index (I2) less than 0.8 dg/min as measured according to ASTM D1238 (2.16 Kg/190 °C), and a molecular weight distribution (MWD ) less than 3.0 as 85249-WO-PCT/DOW 85249 WO measured according to Gel Permeation Chromatography (GPC). 7. The process of any preceding claim, wherein the first reactor polyethylene product has a density greater than 0.930 g/cc, and a melt index (I2) greater than 5.0 dg/min. 8. The process of any preceding claim, wherein the multi-chain catalyst produces a long chain branched fraction of less than 10 wt.% of the ethylene-based polymer. 9. The process of any preceding claim, wherein the ethylene-based polymer has a melt strength (MS) from 4.0 to 25.0 cN, wherein MS is the melt strength in cN (Rheotens device, 190°C, 2.4 mm/s 2 , 120 mm from the die exit to the center of the wheels, extrusion rate of 38.2 s- 1 , capillary die of 30 mm length, 2 mm diameter and 180° entrance angle). 10. The process of claim 9, wherein the melt strength (MS) is from 8.0 to 15 cN. 11. The process of any preceding claim, wherein the ethylene-based polymer has a rheology ratio V0.1/V100 from 4.0 to 12.0, wherein V0.1 is the viscosity of the ethylene-based polymer at 190 °C at an angular frequency of 0.1 radians/second, and V100 is the viscosity of the ethylene- based polymer at 190 °C at an angular frequency of 100 radians/second, and 12. The process of claim 11, wherein the rheology ratio V 0.1 /V 100 is from 4.0 to 8.0. 13. The process of any preceding claim, wherein the ethylene-based polymer has an I2 of 0.5 to 2.0 dg/min.

Description

85249-WO-PCT/DOW 85249 WO PROCESSES FOR MAKING MULTIMODAL ETHYLENE-BASED POLYMERS CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application Serial No. 63/510,766 filed June 28, 2023, the contents of which are incorporated in their entirety herein. TECHNICAL FIELD [0002] Embodiments are generally related to processes for producing ethylene-based polymer and are particularly related to processes for producing ethylene-based polymers, which provide processibility and dart strength in films. BACKGROUND [0003] Linear Low Density Polyethylenes (LLDPE) made via solution or gas phase processes typically have excellent mechanical properties, but poor melt strength and processibility in film fabrication. Therefore, to increase processibility, some amount of LDPE may typically be blended with LLDPE in order to improve the processibility and melt strength of LLDPE resins. Unfortunately, the addition of LDPE leads to decreased mechanical properties of the resulting blends when compared with pure LLDPE resin. [0004] Accordingly, there are needs for ethylene-based polymers suitable to provide processibility and excellent mechanical properties (e.g., dart) without blending with LDPE. SUMMARY [0005] The present ethylene-based polymers achieve this need for processibility and mechanical strength by including at least one polymer fraction having increased long chain branching. Without being limited by theory, this long chain branching provides increased melt strength necessary in film processing, while the ethylene-based polymers still maintain excellent abuse resistance properties in films. [0006] According to one or more embodiments, embodiments are directed to a process for producing ethylene-based polymer in a reactor system comprising a first reactor and a second reactor. The process comprises polymerizing ethylene, one or more (C3-C14)α-olefin monomers, 85249-WO-PCT/DOW 85249 WO and at least one polyene, in the presence of one multi-chain catalyst and at least one single-chain catalyst in the first reactor to produce a first reactor polyethylene product comprising long chain branching, wherein the multi-chain catalyst comprises a plurality of polymerization sites, and wherein the long-chain branching occurs by connecting two polymer chains of the multi-chain catalyst with the polyene in a concerted fashion during the polymerization; and polymerizing ethylene and one or more (C3-C14)α-olefin monomers in the absence of an initial polyene feed and in the presence of at least one single-chain catalyst in the second reactor to produce a second reactor polyethylene product, wherein the ethylene-based polymer comprises the first and second reactor polyethylene products. [0007] These and embodiments are described in more detail in the following Detailed Description in conjunction with the appended drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0008] The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which: [0009] FIG. 1 graphically depicts the molecular weight distribution of the present ethylene- based polymers according to one or more embodiments presently described; and [0010] FIG. 2 graphically illustrates the relationship between melt strength and normalized dart strength for the present ethylene-based polymers according to one or more embodiments presently described. DETAILED DESCRIPTION [0011] Specific embodiments of a process for synthesizing polymer and polymers synthesized by the process of this disclosure will now be described. It should be understood that the process for synthesizing polymers of this disclosure may be embodied in different forms and should not be construed as limited to the specific embodiments set forth in this disclosure. Rather, embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the subject matter to those skilled in the art. 85249-WO-PCT/DOW 85249 WO [0012] DEFINITIONS [0013] The term “polymer” refers to a polymeric compound prepared by polymerizing monomers, whether of the same or a different type. The generic term polymer thus embraces the term “homopolymer,” usually employed to refer to polymers prepared from only one type of monomer as well as “copolymer” which refers to polymers prepared from two or more different monomers. [0014] “Polyethylene” or “ethylene-based polymer” shall mean polymers comprising greater than 50% by weight of units which have been derived from ethylene monomer. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more comonomers). Common forms of polyethylene known in the art include Low Density Polyethylene (LDPE); Linear Low Density Polyethylene (LLDPE); Ultra Low Density Polyethylene (ULDPE); Very Low Density Polyethylene (VLDPE);