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CN-122029229-A - Polyethylene composition for improved collation shrink film

CN122029229ACN 122029229 ACN122029229 ACN 122029229ACN-122029229-A

Abstract

Disclosed herein is a polymer blend comprising a Low Density Polyethylene (LDPE) and less than 10wt.% of a High Density Polyethylene (HDPE), wherein the LDPE comprises a density of 0.910g/cc to 0.925g/cc, a melt index (I2) of 0.2dg/min to 0.8dg/min, and a M w (cc)/M n (cc) of 4 to 10, wherein the HDPE comprises a density of 0.940g/cc to 0.970g/cc, a I2 of 0.6dg/min to 10dg/min, and a M w (cc)/M n (cc) of 2 to 5, and wherein the polymer blend comprises a density of 0.918g/cc to 0.926g/cc, a I2 of 0.2dg/min to 0.8dg/min, and a M w (cc)/M n (cc) of 4 to 9.

Inventors

  • QIAO YUSEN
  • T.P. Caliara
  • M. D. Sanchez
  • L. Fran ç ois
  • J. Barreman
  • J. D. Mendenhall
  • P. DUMONT
  • S. Parkinson

Assignees

  • 陶氏环球技术有限责任公司

Dates

Publication Date
20260512
Application Date
20241017
Priority Date
20231024

Claims (12)

  1. 1. A polymer blend comprising a Low Density Polyethylene (LDPE) and less than 10wt.% of a High Density Polyethylene (HDPE), wherein: the LDPE comprises a density of 0.910g/cc to 0.925g/cc, a melt index (I2) of 0.2dg/min to 0.8dg/min, and a M w (cc)/M n (cc) of 4 to 10; The HDPE includes a density of 0.940g/cc to 0.970g/cc, an I2 of 0.6dg/min to 10dg/min and a M w (cc)/M n (cc) of 2 to 5, and The polymer blend includes a density of 0.918g/cc to 0.926g/cc, an I2 of 0.2dg/min to 0.8dg/min, and a M w (cc)/M n (cc) of 4 to 9.
  2. 2. The polymer blend of claim 1 wherein the density of the LDPE is from 0.920g/cc to 0.925g/cc, the I2 of the LDPE is less than 0.5dg/min, and the M w (cc)/M n (cc) of the LDPE is from 6 to 9.
  3. 3. The polymer blend of claim 1 or 2, wherein the LDPE has an M z (abs)/M w (abs) of 5 to 20 and a gpcBR of greater than 0.05 as measured according to TD-GPC.
  4. 4. The polymer blend of any of claims 1 to 3, wherein the LDPE has a melt strength of 15cN to 25 cN.
  5. 5. The polymer blend of any of claims 1-4, wherein the polymer blend comprises 2wt.% to 10wt.% HDPE or 3.5wt.% to 5wt.% HDPE.
  6. 6. The polymer blend of any one of claims 1 to 5, wherein the polymer blend has an M z (abs)/M w (abs) of 14 to 21 and a gpcBR of greater than 0.05.
  7. 7. The polymer blend of any one of claims 1 to 6, wherein the I2 of the polymer blend is less than 0.5dg/min.
  8. 8. The polymer blend of any one of claims 1 to 7, wherein the polymer blend has a melt strength of 15cN to 20 cN.
  9. 9. A film comprising the polymer blend of any one of claims 1 to 8, wherein the film is a monolayer film or a multilayer film.
  10. 10. The film of claim 9, wherein the film is a multilayer film comprising the polymer blend in a core layer.
  11. 11. A composition comprising an ethylene-based polymer, wherein the ethylene-based polymer comprises a density of 0.918g/cc to 0.926g/cc, an I2 of 0.2g/min to 0.8dg/min, and an M w (cc)/M n (cc) of 4 to 9.
  12. 12. The composition of claim 11, wherein the ethylene-based polymer is LDPE.

Description

Polyethylene composition for improved collation shrink film Cross Reference to Related Applications The present application claims the benefit of european patent application serial number 23383090.0 filed at month 24 of 2023, the contents of which are incorporated by reference in their entirety. Technical Field The present application relates to polymer compositions, and in particular to compositions comprising Low Density Polyethylene (LDPE) based polymers blended with High Density Polyethylene (HDPE) based polymers. Background The use of polyolefin compositions in packaging applications is well known. In particular, low Density Polyethylene (LDPE) with elevated density (> 0.925 g/cc) is attractive in flexible packaging applications, including collation shrink, shrink wrap, heavy duty shipping bags, and industrial heavy duty films, because it imparts good mechanical properties (e.g., stiffness) to the film, while maintaining good optical properties. However, for polyethylene blends with elevated densities, maintaining good optical properties is challenging. In general, increasing the density of polyethylene will increase the crystallinity, thereby negatively affecting the optical properties. While blending with HDPE results in higher density and improved mechanical properties such as stiffness, blending with HDPE generally results in reduced optical properties. Thus, there is a need for improved polyethylene compositions that exhibit good mechanical and optical properties. Disclosure of Invention Embodiments of the present disclosure address this need by utilizing an LDPE base resin having a slightly lower density (+.0.925 g/cc) and a minimum amount of HDPE (< 10 wt.%) to produce an unexpectedly good balance of LDPE/HDPE polymer composition with film mechanical and optical properties. Without being limited by theory, maintaining HDPE below 10wt.% enables the blend to maintain optical properties while providing stiffness and mechanical properties. The first aspect includes a polymer blend comprising a Low Density Polyethylene (LDPE) and less than 10wt.% of a High Density Polyethylene (HDPE), wherein the LDPE comprises a density of 0.910g/cc to 0.925g/cc, a melt index (I2) of 0.2dg/min to 0.8dg/min, and a M w(cc)/Mn (cc) of 4 to 10, the HDPE comprises a density of 0.940g/cc to 0.970g/cc, a I2 of 0.6dg/min to 10dg/min, and a M w(cc)/Mn (cc) of 2 to 5, and the polymer blend comprises a density of 0.918g/cc to 0.926g/cc, a I2 of 0.2dg/min to 0.8dg/min, and a M w(cc)/Mn (cc) of 4 to 9. A second aspect includes the polymer blend of the first aspect, wherein the LDPE has a density of from 0.920g/cc to 0.925g/cc, an I2 of the LDPE of less than 0.5dg/min, and an M w(cc)/Mn (cc) of the LDPE of from 6 to 9. A third aspect comprises the polymer blend of the first or second aspect, wherein the LDPE has an M z(abs)/Mw (abs) of 5 to 20 and a gpcBR of greater than 0.05 as measured according to triple detector GPC (TD-GPC), wherein "abs" refers to absolute molecular weight. A fourth aspect includes the polymer blend of any of the first to third aspects, wherein the LDPE has a melt strength of 15cN to 25 cN. A fifth aspect comprises the polymer blend of any of the first to fourth aspects, wherein the polymer blend comprises 2wt.% to 10wt.% HDPE or 3.5wt.% to 5wt.% HDPE. A sixth aspect comprises the polymer blend of any of the first to fifth aspects, wherein the polymer blend has an M z(abs)/Mw (abs) of 14 to 21 and a gpcBR of greater than 0.05. A seventh aspect includes the polymer blend of any of the first to sixth aspects, wherein the I2 of the polymer blend is less than 0.5dg/min. The eighth aspect includes the polymer blend of any of the first to seventh aspects, wherein the polymer blend has a melt strength of 15cN to 25 cN. A ninth aspect comprises a film comprising the polymer blend of any one of the first to eighth aspects, wherein the film is a monolayer film or a multilayer film. A tenth aspect includes the film of the ninth aspect, wherein the film is a multilayer film comprising a polymer blend in a core layer. An eleventh aspect includes a composition comprising an ethylene-based polymer, wherein the ethylene-based polymer comprises a density of 0.918g/cc to 0.926g/cc, an I2 of 0.2dg/min to 0.8dg/min, and a Mw (cc)/Mn (cc) of 4 to 9. A twelfth aspect includes the composition of the eleventh aspect, wherein the ethylene-based polymer is LDPE. 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 detailed description and the claims which follow. It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. Drawings T