EP-4735490-A1 - MULTIMODAL ETHYLENE-BASED COPOLYMER COMPOSITIONS AND PROCESSES OF PRODUCING

Abstract

Processes of making a multimodal ethylene-based copolymer. The processes include adding ethylene, at least one olefinic monomer, at least a first catalyst system, and less than 0.3 mol% hydrogen gas to a solution polymerization reactor to create an effluent feed at a reactor temperature of greater than or equal to 100 °C. The effluent feed and a second catalyst system is fed to a second reactor absent fresh feed and absent hydrogen gas. At least one of the first catalyst system and the second catalyst system have a chain transfer constant of from 0.005 to 1.0. The multimodal ethylene-based copolymer comprises a high molecular weight fraction, meaning the molecular weight fraction that is greater than 500,000 g/mol, from 8% to 50% based on the total percent of the multimodal ethylene-based copolymer.

Inventors

• ROSEN, Mari S.
• FONTAINE, PHILIP P.
• KLOSIN, JERZY
• CARNAHAN, EDMUND M.
• Wang, Alex Y.
• DAZA, YOLANDA A.
• HAMAD, Fawzi G.
• BALDING, Paul
• PEREIRA, Joana Amaral

Assignees

• Dow Global Technologies LLC

Dates

Publication Date

20260506

Application Date

20240613

Claims (1)

1. 85250-WO-PCT/DOW 85250 WO CLAIMS 1. A process of making a multimodal ethylene-based copolymer, comprising: adding ethylene, at least one olefinic monomer, at least a first catalyst system, and less than 0.3 mol% hydrogen gas to a solution polymerization reactor to create an effluent feed at a reactor temperature of greater than or equal to 150 °C, where mol% hydrogen is based on the moles of ethylene in the feed; feeding the effluent feed and a second catalyst system to a second reactor absent fresh feed and absent hydrogen gas; wherein: the first catalyst system comprises a first procatalyst and a first activator; and the second catalyst system comprises a second procatalyst and optionally a second activator; at least one of the first catalyst system and the second catalyst system have a chain transfer constant of from 0.005 to 1.0 and wherein the multimodal ethylene-based copolymer comprises a high molecular weight fraction, computed by measuring an area fraction of a molecular weight chromatogram obtained from absolute molecular weights from low angle light scattering greater than 500,000 g/mol of from 8% to 50% based on the total percent of the multimodal ethylene-based copolymer. 2. The process of claim 1, wherein 4one of the first catalyst system and the second catalyst system are capable of producing a polymer with a native molecular weight of greater than 100,000 g/mol, wherein the polymer native molecular weight is measured in a single 1 Gal reactor in the presence of 1250 grams of ISOPAR-E, with an ethylene pressure of 320 psi, an 1- octene amount of 60 g, 0 H2 and at a reactor temperature of at least 150°C. 85250-WO-PCT/DOW 85250 WO 3. The process of claim 2, wherein the other of the first catalyst system and the second catalyst system are capable of producing a polymer with a native molecular weight of less than 150,000 g/mol, wherein the polymer native molecular weight is measured in a single 1 Gal reactor in the presence of 1250 grams of ISOPAR-E, with an ethylene pressure of 320 psi, an 1- octene amount of 60 g, 0 H2 and at a reactor temperature of at least 160°C. 4. The process of claim 1, wherein the first catalyst system is capable of producing a first polymer having a native molecular weight and the second catalyst system is capable of producing a second polymer having a native molecular weight with a difference of at least 80,000 g/mol from the native molecular weight of the first polymer. 5. The process of any one of the preceding claims, wherein the solution polymerization reactor is a continuous stirred tank reactor, a loop reactor, or a plug flow reactor. 6. The process of any one of the preceding claims, wherein the second polymerization reactor is non-agitated reactor. 7. The process of claim 4, wherein the non-agitated reactor is a plug flow reactor. 8. The process of any one of the preceding claims, wherein at least one of the first catalyst and the second catalyst have a reactivity ratio of less than 20, wherein the reactivity ratio of the catalyst is measured in a single 1 Gal reactor with only the catalyst system in the presence of 1250 grams of ISOPAR-E, with a mol fraction of ethylene in solution of 0.709, 60 g 1-octene, and at a reactor temperature of at least 150°C. 85250-WO-PCT/DOW 85250 WO 9. The process of any one of the preceding claims, wherein the multimodal ethylene-based copolymer further comprises a low molecular weight fraction, computed by measuring an area fraction of a molecular weight chromatogram obtained from absolute molecular weights from low angle light scattering less than 500,000 g/mol, is greater than or equal to 50 % based on the total percent of the multimodal ethylene-based copolymer. 10. The process of any one of the preceding claims, wherein the multimodal ethylene-based copolymer further comprises a high molecular weight fraction, computed by measuring an area fraction of a molecular weight chromatogram obtained from absolute molecular weights from low angle light scattering greater than 500,000 g/mol, is greater than or equal to 10 % to 50% based on the total percent of the multimodal ethylene-based copolymer. 11. The process of any one of the preceding claims, wherein the multimodal ethylene-based copolymer further comprises a high molecular weight fraction, computed by measuring an area fraction of a molecular weight chromatogram obtained from absolute molecular weights from low angle light scattering greater than 500,000, is from 20 % to 50% based on the total percent of the multimodal ethylene-based copolymer. 12. The process of any one of the preceding claims, wherein the multimodal ethylene-based copolymer has a density of from 0.900 g/cc to 0.940 g/cc measured according to ASTM D792. 13. The process of any one of the preceding claims, wherein the multimodal ethylene-based copolymer has a melt strength of at least 5 cN and a melt index (I2) of at least 0.5 g/10 minutes measured according to ASTM 1238 at 2.16 kg and 190°C. 85250-WO-PCT/DOW 85250 WO 14. The process of any one of the proceeding claims, wherein the multimodal ethylene-based copolymer has a melt strength (MS) that satisfies the following formula: wherein x is equal to 15, y is equal to 1, and I2 is a melt index of the copolymer measured according to ASTM 1238 at 2.16 kg and 190°C. 15. The process of any one of the preceding claims, where the V 0.1 /V 100 value as determined by dynamic mechanical analysis is greater than 10. 16. The process of any one of the preceding claims, wherein the first reactor temperature is from 160 °C to 200 °C. 17. The process of any one of the preceding claims wherein the first procatalyst is selected from one of the following: A and 85250-WO-PCT/DOW 85250 WO . 18. The process of any one of the preceding claims wherein the second procatalyst is selected from one of the following: 19. The process of any one of the preceding claims, wherein the process further includes a third catalyst system.

Description

85250-WO-PCT/DOW 85250 WO MULTIMODAL ETHYLENE-BASED COPOLYMER COMPOSITIONS AND PROCESSES OF PRODUCING CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application Serial No. 63/510,779 filed June 28, 2023, the contents of which are incorporated in their entirety herein. TECHNICAL FIELD [0002] Embodiments of the present disclosure generally relate to polymer compositions and more specifically relate to multimodal ethylene-based copolymer compositions and processes of producing the same. BACKGROUND [0003] The use of polyolefin compositions in industries such as packaging applications is generally known. A variety of conventional methods may be employed to produce such polyolefin compositions. Various polymerization techniques using different catalyst systems have been employed to produce such polyolefin compositions suitable for packaging applications. However, despite the research efforts in developing compositions suitable for, in some embodiments, packaging applications, there is still a need for improved polyethylene compositions suitable for packaging applications that may have a good balance of physical properties and melt strength at desired polymer composition densities. SUMMARY [0004] Melt strength and processability are correlated properties of polyethylene resins. In general, a higher melt strength provides for a polyethylene resin with improved processability. [0005] Additionally, conventional polyethylene resins produced by conventional processes typically see a tradeoff between the resin’s mechanical properties and melt strength. For example, conventional radical processes, which are known to be hazardous, produce low density polyethylenes (LDPE) that typically exhibit high melt strength but have poor mechanical properties. In contrast, linear low-density polyethylenes (LLDPE) made via solution or gas phase processes typically have poor melt strength but excellent mechanical properties. [0006] Therefore, to increase processability, some amount of LDPE may typically be blended with LLDPE in order to improve the processability 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. 85250-WO-PCT/DOW 85250 WO [0007] Accordingly, there are needs for solution polymerization processes that produce polyethylene resins that may have melt strengths comparable to polyethylene resins produced via a radical process. In particular, there are needs for solution polymerization processes that produce polyethylene resins that may have melt strengths comparable to LDPE resins produced via a radical process. Thus, there is a need to produce a high molecular weight (HMW) polyethylene copolymer and a low molecular weight (LMW) polyethylene copolymer to create multimodal ethylene-based copolymers. These multimodal ethylene-based copolymers with a HMW ethylene-based copolymer component have higher melt strengths than polyethylenes of similar melt indices without this HMW polyethylene component. [0008] Embodiments of the present disclosure meet those needs by providing multimodal ethylene-based copolymers that comprise a bulk low molecular weight (LMW) ethylene-based component made by one catalyst or catalysts and a high molecular weight (HMW) ethylene-based component made by a different catalyst or catalysts. The multimodal ethylene-based copolymers described herein may possess long chain branching that, along with the HMW ethylene-based component, allows for melt strengths to be achieved that are comparable to or higher than various LDPEs produced via conventional processes. Consequently, the multimodal ethylene-based copolymers described herein may be used as blend components with LLDPEs in lesser amounts than what is needed for conventional LDPE resins, thereby leading to improved mechanical properties of the resulting LLDPE blends when compared to the mechanical properties in conventional LLDPE/LDPE blends. In embodiments, the multimodal ethylene-based copolymers are produced via a solution polymerization process. [0009] Embodiments of this disclosure include a process utilizing the use of a low H2 level. Controlling the levels of H2 in a reactor may allow the molecular weight of the ethylene-based copolymers to be regulated. If the H2 level is too high, the molecular weight difference between the polymers produced by the two catalysts may be diminished to the point where there is no HMW ethylene-based copolymer component (and both catalysts would be producing LMW PE) and no melt strength improvement is obtained. [0010] Embodiments of this disclosure include processes of making a multimodal ethylene- based copolymer. In embodiments, the process includes adding ethylene, at least one olefinic monomer, at least a first catalyst system, and less than 0.3 mol% hydrogen gas to a solution polymerization reactor to create an effluent feed at a reactor