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US-12617883-B2 - Compositions with multimodal ethylene-based polymers having improved toughness at low temperatures

US12617883B2US 12617883 B2US12617883 B2US 12617883B2US-12617883-B2

Abstract

Embodiments of a polymer compositions and articles comprising such compositions contain at least one multimodal ethylene-based polymer, wherein the multimodal ethylene-based polymer exhibits superior low temperature performance.

Inventors

  • Didem Oner-Deliormanli
  • Yijian Lin
  • Mehmet Demirors
  • Jong Young Lee
  • David T. Gillespie

Assignees

  • DOW GLOBAL TECHNOLOGIES LLC

Dates

Publication Date
20260505
Application Date
20181219

Claims (14)

  1. 1 . A polymer composition comprising: at least one multimodal ethylene-based polymer having a density from 0.900 to 0.930 g/cc when measured according to ASTM D792 and a melt index (I 2 ) from 0.1 to 10.0 g/10 min when measured according to ASTM D1238 at a load of 2.16 kg and temperature of 190° C., the multimodal ethylene-based polymer comprising a first ethylene-based component, a second ethylene-based component, and a third ethylene-based component, wherein each of the first ethylene-based component, the second ethylene-based component, and the third ethylene-based component are polymerized reaction products of ethylene monomer and at least one C 3 -C 12 α-olefin comonomer, wherein: the first ethylene-based component has a density of 0.870 to 0.900 g/cc, a melt index (I2) from 0.02 to 0.15 g/10 min, a weight-average molecular weight (Mw(GPC)) of 128,000 g/mol to 363,000 g/mol, and comprises 3 to 20 mol. % of C 3 -C 12 α-olefin comonomer, the multimodal ethylene-based polymer comprising at least 20% by weight of the first ethylene-based component; the second ethylene-based component has a density greater than the density of the first ethylene-based component and from 0.900 to 0.920 g/cc, a melt index (I 2 ) from 0.2 to 1.0 g/10 min, and a weight-average molecular weight (M w(GPC) ) of 88,500 g/mol to 363,000 g/mol, comprises 3 to 20 mol. % of C 3 -C 12 α-olefin comonomer, and a lower C 3 -C 12 α-olefin comonomer incorporation than the first ethylene-based component; and the third ethylene-based component has a density greater than the density of the second ethylene-based component and from 0.940 to 0.960 g/cc, and a melt index (I 2 ) from 150 to 2000 g/10 min.
  2. 2 . The polymer composition of claim 1 , wherein the multimodal ethylene-based polymer comprises from 20 to 50% by weight of the first ethylene-based component, from 10 to 40% by weight of the second ethylene-based component, and 25 to 60% by weight of the third ethylene-based component.
  3. 3 . The polymer composition of claim 1 , wherein the melt index (I 2 ) of the multimodal ethylene-based polymer is from 0.5 to 5.0 g/10 min, and the density of the multimodal ethylene-based polymer is from 0.905 to 0.930 g/cc.
  4. 4 . The polymer composition of claim 1 , wherein the multimodal ethylene-based polymer has an I 10 /I 2 value from 8 to 15, wherein I 10 is measured according to ASTM D1238 at a load of 10 kg and temperature of 190° C.
  5. 5 . The polymer composition of claim 1 , wherein the multimodal ethylene-based polymer has a Crystallization Elution Fractionation (CEF) weight fraction greater than 22% and a weight averaged molecular weight (M w(CEF) ) greater than 130,000 g/mol at a temperature range from 20° C. to T critical (T c ).
  6. 6 . The polymer composition of claim 1 , wherein the polymer composition further comprises at least one low density polyethylene (LDPE) having a density of 0.916 to 0.935 g/cc and a melt index (I 2 ) from 0.1 to 10.0 g/10 min when measured according to ASTM D1238 at a load of 2.16 kg and temperature of 190° C.
  7. 7 . The polymer composition of claim 1 , wherein the multimodal ethylene-based polymer has a molecular weight distribution (M w(GPC) /M n(GPC) ) of at least 4.3.
  8. 8 . The polymer composition of claim 1 , wherein the multimodal ethylene-based polymer comprises 35 to 50% by weight of the third ethylene-based component.
  9. 9 . A film comprising the polymer composition of claim 1 , wherein the film is a blown film having an Instrumented Dart Impact (IDI) of greater than 0.3 J at a temperature of −20° C. and a 1 mil thickness.
  10. 10 . A multilayer film comprising a core layer, and at least two skin layers disposed on opposite sides of the core layer, wherein: the core layer and one or more of the skin layers comprise the polymer composition of claim 1 , and one or more of the skin layers comprise at least one low density polyethylene (LDPE) having a density of 0.916 to 0.935 g/cc and a melt index (I2) from 0.1 to 10 g/10 min when measured according to ASTM D1238 at a load of 2.16 kg and a temperature of 190° C., wherein the multilayer film is a blown or cast film.
  11. 11 . The multilayer film of claim 10 further comprising sub-skin layers disposed between the core layer and skin layers, wherein the sub-skin layers comprise the polymer composition of claim 1 and the LDPE.
  12. 12 . The multilayer film of claim 11 , wherein the multilayer film is a blown film having an Instrumented Dart Impact (IDI) Total Energy at −20° C. of at least 0.60 J at a 2 mil thickness.
  13. 13 . The polymer composition of claim 1 , wherein the multimodal ethylene-based polymer has a molecular weight distribution (M w(GPC) /M n(GPC) ) of from 4.3 to 12.
  14. 14 . The polymer composition of claim 1 , wherein the third ethylene-based component has a melt index (I 2 ) from 300 to 2000 g/10 min.

Description

CROSS-REFERENCE This application is a National Stage Entry under 35 U.S.C. § 371 of International Patent Application No. PCT/US2018/066581, filed Dec. 19, 2018, which claims priority to U.S. Provisional Patent Application Ser. No. 62/610,398 filed, Dec. 26, 2017, both of which are incorporated by reference herein in their entireties. TECHNICAL FIELD Embodiments of the present disclosure generally relate to ethylene-based polymer compositions, and more specifically relate to compositions comprising multimodal ethylene-based polymers that deliver excellent physical properties (e.g., toughness) at low temperatures for use in, for example, frozen food packaging applications. BACKGROUND In monolayer and multilayer polymer films, which may include blown or cast films, it is beneficial for the films to demonstrate toughness in various temperature conditions, such as temperatures below freezing (i.e., 0° C. and below). However, obtaining polymer films which have sufficient strength at low temperatures is often challenging. SUMMARY Accordingly, ongoing needs exist for multimodal ethylene-based polymer compositions with improved performance at cold temperatures (i.e., 0° C. and below). The present multimodal ethylene-based polymers meet these needs and display show a superior low temperature performance (for example, dart strength, and secant modulus) than conventional bimodal or unimodal polyethylene compositions. According to at least one embodiment of the present disclosure, a polymer composition is provided. The composition includes at least one multimodal ethylene-based polymer. Overall, the multimodal ethylene-based polymer has a density from 0.900 to 0.930 grams per cubic centimeter (g/cc) and a melt index (I2) from 0.1 to 10.0 grams per 10 minutes (g/10 min) when measured according to ASTM D1238 at a load of 2.16 kilograms (kg) and a temperature of 190 degrees Celsius (° C.). The multimodal ethylene-based polymer comprises three ethylene-based components, which are polymerized reaction products of an ethylene monomer and at least one C3-C12 α-olefin comonomer. The first ethylene-based component has a density of 0.855 to 0.900 g/cc, and a weight-average molecular weight (Mw(GPC)) of 128,000 g/mol to 363,000 g/mol. The second ethylene-based component has a density greater than the density of the first ethylene-based component and less than 0.930 g/cc, and a weight-average molecular weight (Mw(GPC)) of 88,500 g/mol to 363,000 g/mol. The third ethylene-based component has a density greater than the density of the second ethylene-based component. Additionally, according to other embodiments, a polymer composition is provided that includes a low density polyethylene (LDPE) component. Finally, according to other embodiments, monolayer films, multilayer films, and articles comprising the polymer compositions are provided. These and other embodiments are described in more detail in the following Detailed Description. BRIEF DESCRIPTION OF THE DRAWINGS 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: FIG. 1 is a graphical illustration depicting the Crystallization Elution Fractionation (CEF) weight % fraction versus temperature for Inventive Polymer 5 and Comparative Polymer 3. FIG. 2 depicts side-by-side Short Chain Branching Distribution (SCBD) Elution Profiles and Molecular Weight Distribution (MWD) plots of Inventive Polymer 2, which is used for estimating the initial parameters for the numerical deconvolution process described below. DETAILED DESCRIPTION Specific embodiments of the present application will now be described. The disclosure may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth in this disclosure. Rather, these 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. Definitions 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. The term “interpolymer,” as used herein, refers to a polymer prepared by the polymerization of at least two different types of monomers. The generic term interpolymer thus includes copolymers, and polymers prepared from more than two different types of monomers, such as terpolymers. As used herein, “multimodal” means compositions that can be characterized by having at least three polymer subcomponents with varying densities and weight averaged molecular weights, and optionally, may also have different melt index values. In o