EP-4735511-A1 - POLYMER FILMS HAVING SUPERIOR COMBINATION OF PROCESSIBILITY AND ABUSE RESISTANCE

EP4735511A1EP 4735511 A1EP4735511 A1EP 4735511A1EP-4735511-A1

Abstract

Embodiments of the present disclosure are directed to films comprising at least 95 wt.% ethylene-based polymer, wherein: the ethylene-based polymer is the polymerized reaction product of ethylene, C 3 -C 14 α-olefin monomer, and optionally polyene; and wherein the film comprises a normalized dart strength (DS) in g/mol that is greater than or equal to 400 + 1400 / (MS - 2.7), wherein normalized DS is measured in gram (g/mil) according to ASTM 1709 Method A divided by the film thickness in mil, wherein MS is the melt strength of the ethylene-based polymer measured in centiNewtons (cN) (Rheotens device, 190°C, 2.4 mm/s2, 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), and wherein the MS is at least 4 cN.

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)

85198-WO-PCT/DOW 85198 WO CLAIMS 1. A film comprising at least 95 wt.% ethylene-based polymer, wherein: the ethylene-based polymer is the polymerized reaction product of ethylene, C3-C14 α- olefin monomer, and optionally polyene; and wherein the film comprises a normalized dart strength (DS) in g/mil that is greater than or equal to 400 + 1400 / (MS - 2.7), wherein normalized DS is dart strength measured in gram (g) according to ASTM 1709 Method A divided by the film thickness in mil, wherein MS is the melt strength of the ethylene-based polymer measured in centiNewtons (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), and wherein the MS is at least 4 cN. 2. The film of claim 1, wherein the film is substantially free of any other polymeric component. 3. The film of any preceding claim, wherein the film is a monolayer or multilayer film. 4. The film of any preceding claim, wherein the ethylene-based polymer is the polymerized reaction product of ethylene, C3-C12 α-olefin, and polyene. 5. The film of any preceding claim, wherein the ethylene-based polymer has a rheology ratio V0.1/V100 from 4.0 to 12, 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. 6. The film of claim 5, wherein the rheology ratio V 0.1 /V 100 is from 4.0 to 8.0. 7. The film of any preceding claim, wherein the ethylene-based polymer has an I2 of 0.5 to 2.0 dg/min as measured according to ASTM D1238 (2.16 Kg/190 °C). 8. The film of any preceding claim, wherein the ethylene-based polymer has a density of 0.910 to 0.935 g/cc. 85198-WO-PCT/DOW 85198 WO 9. The film of any preceding claim, wherein the ethylene-based polymer is a multimodal polymer. 10. The film of any preceding claim, wherein the ethylene-based polymer has an MWD of 3.0 to 5.0, MWD is defined as M w /M n with M w being a weight average molecular weight and M n being a number average molecular weight as measured according to conventional Gel Permeation Chromatography. 11. The film of any preceding claim, wherein the melt strength (MS) is from 4.0 to 25 cN, or from 8.0 to 15 cN. 12. The film of any preceding claim, wherein the normalized DS of the film is from 750 to 1750 g/mil. 13. The film of any proceeding claims, where the normalized DS in g/mil is greater than or equal to 430 + 2000 / (MS - 2.4). 14. The film of any proceeding claims, where the normalized DS in g/mil is greater than or equal to 400 + 2736 / (MS - 2.2). 15. The film of any proceeding claims, where the normalized DS in g/mil is greater than or equal to 390 + 3900 / (MS - 2.5). 16. The film of any proceeding claims, wherein the film has an average thickness of 1.0 to 3.0 mil.

Description

85198-WO-PCT/DOW 85198 WO POLYMER FILMS HAVING SUPERIOR COMBINATION OF PROCESSIBILITY AND ABUSE RESISTANCE CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application Serial No. 63/510,763 filed June 28, 2023, the contents of which are incorporated in their entirety herein. TECHNICAL FIELD [0002] Embodiments are generally related to ethylene-based polymer films and are particularly related to ethylene-based polymer films having processibility and dart strength. 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 polymer films having processibility and excellent mechanical properties (e.g., dart) without blending with LDPE. SUMMARY [0005] The present embodiments achieve this need for processibility and mechanical strength by including ethylene-based polymers having at least one polymer fraction withincreased 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, a film comprising at least 95 wt.% ethylene- based polymer is provided. The ethylene-based polymer is the polymerized reaction product of ethylene, C3-C14 α-olefin monomer, and optionally polyene. The film comprises a normalized dart 85198-WO-PCT/DOW 85198 WO strength (DS) that is greater than or equal to 400 + 1400 / (MS - 2.7), wherein normalized DS is measured in gram (g/mil) according to ASTM 1709 Method A divided by the film thickness in mil, wherein MS is the melt strength of the ethylene-based polymer measured in centiNewtons (cN) (Rheotens device, 190°C, 2.4 mm/s2, 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), and wherein the MS is at least 4 cN. [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] 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: [0010] FIG.1 graphically depicts the molecular weight distribution of the present multimodal ethylene-based polymers according to one or more embodiments presently described; and [0011] FIG. 2 graphically illustrates the relationship between melt strength and normalized dart strength for the present multimodal ethylene-based polymers according to one or more embodiments presently described. DETAILED DESCRIPTION [0012] 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. 85198-WO-PCT/DOW 85198 WO [0013] DEFINITIONS [0014] 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. [0015] “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); single-site catalyzed Linear Low Densi