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EP-4735249-A1 - CLING FILM

EP4735249A1EP 4735249 A1EP4735249 A1EP 4735249A1EP-4735249-A1

Abstract

The present disclosure provides a film. In an embodiment, the film includes a core structure having a first side and an opposing second side. The core structure includes a release layer. The release layer is composed of an ethylene-based polymer on the first side. A cling layer is on the second side of the core structure. The cling layer includes an acrylic polymer. The film has a cling force from 300 g to 1100 g at 100% stretch.

Inventors

  • COLOMBO, Veronica
  • PALOMO, Jesus, Nieto
  • MARIANI, ALESSANDRO

Assignees

  • DOW GLOBAL TECHNOLOGIES LLC
  • Rohm and Haas Company

Dates

Publication Date
20260506
Application Date
20240412

Claims (9)

  1. 1. A film comprising: a core structure having a first side and an opposing second side, the core structure comprising a release layer composed of an ethylene-based polymer on the first side; a cling layer on the second side of the core structure, the cling layer comprising an acrylic polymer; and the film has a cling force from 300 g to 1100 g at 100% stretch.
  2. 2. The film of claim 1 wherein the core structure comprises the release layer and one or more other layers.
  3. 3. The film of claim 2 wherein the core structure comprises one or more ethylene-based polymers.
  4. 4. The film of any of claims 1-3 wherein the cling layer comprises an acrylic polymer having a butyl acrylate monomer.
  5. 5. The film of claim 4 wherein the cling layer (i) has a thickness from 4 GSM to 10 GSM; and (ii) the film has a cling force from 450g to 1100g at 100% stretch.
  6. 6. The film of any of claims 1-5 wherein the second side of the core structure comprises a surface-treated layer having a surface energy of at least 38 dynes/cm 2 .
  7. 7. A process comprising: stretching a film to at least 100%, the film comprising a core structure having a first side and an opposing second side, the core structure comprising a release layer composed of an ethylene-based polymer on the first side, a cling layer on the second side of the core structure, the cling layer comprising an acrylic polymer; wrapping the film around a bale of a forage crop; contacting the cling layer to the release layer; and adhering the cling layer to the release layer at a cling force from 300 g to 1000 g at 100% stretch.
  8. 8. The process of claim 7 comprising forming, with the film, a barrier around the bale.
  9. 9. The process of any of claims 7-8 comprising contacting a portion of the bale with a portion of the cling layer.

Description

CLING FILM BACKGROUND [0001] Polymeric films have wide application in packaging because the properties of polymeric films can be tailored for a desired end use. Overwrap films, for example, are used for packaging goods, foodstuffs, forage crops and bale. In such applications, it is important for the overwrap film to have good barrier properties, good mechanical, cling, and stretch properties, good toughness, and strong resistance to puncture, impact, and tear. [0002] Silage films are used to store grass and other animal feed crop at farms during the nongrowing season. The typical silage bale wrap film contains a core layer that provides mechanical performance for the film, a cling layer that provides sufficient stickiness and adherence, and a release layer that prevents blockage, decreases the roll unwinding force, and controls unwinding noise. The cling layer typically includes polyisobutylene (PIB) to provide stickiness and cling. PIB is problematic because PIB (i) is a sticky liquid and is difficult to handle; (ii) produces plate-out and contaminates equipment; (iii) is migratory and therefore needs to be incorporated into the core layer in order to reduce bloom-out; and (iv) can impart telescoping effects onto the film. [0003] Therefore, a need exists for a cling film with improved cling performance for silage applications that avoids PIB. SUMMARY [0004] The present disclosure provides a film. In an embodiment, the film includes a core structure having a first side and an opposing second side. The core structure includes a release layer. The release layer is composed of an ethylene-based polymer on the first side. A cling layer is on the second side of the core structure. The cling layer includes an acrylic polymer. The film has a cling force from 300 g to 1100 g at 100% stretch. BRIEF DESCRIPTION OF THE DRAWINGS [0005] Figure 1 is a graph showing the cling force for examples in accordance with embodiments of the present disclosure. [0006] Any reference to the Periodic Table of Elements is that as published by CRC Press, Inc., 1990- 1991. Reference to a group of elements in this table is by the new notation for numbering groups. [0007] For purposes of United States patent practice, the contents of any referenced patent, patent application or publication are incorporated by reference in their entirety (or its equivalent US version is so incorporated by reference) especially with respect to the disclosure of definitions (to the extent not inconsistent with any definitions specifically provided in this disclosure) and general knowledge in the art. [0008] The numerical ranges disclosed herein include all values from, and including, the lower and upper value. For ranges containing explicit values (e.g., 1 or 2, or 3 to 5, or 6, or 7), any subrange between any two explicit values is included (e.g., 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6; etc.). [0009] Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percents are based on weight and all test methods are current as of the filing date of this disclosure. [0001] An "acrylic-based monomer," as used herein, is a monomer having the Structure (I) below: Structure (I) wherein Ri is a H or a Ci-Cis alkyl group, or a C1-C4 alkyl group and R2 is H or CH3. Nonlimiting examples of acrylic comonomers include acrylic acid, methacrylic acid, acrylates, and methacrylates. [0010] The term "composition" refers to a mixture of materials which comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition. [0011] The terms "blend" or "polymer blend," as used herein, is a blend of two or more polymers. Such a blend may or may not be miscible (not phase separated at molecular level). Such a blend may or may not be phase separated. Such a blend may or may not contain one or more domain configurations, as determined from transmission electron spectroscopy, light scattering, x-ray scattering, and other methods known in the art. [0012] The terms "comprising," "including," "having" and their derivatives, are not intended to exclude the presence of any additional component, step or procedure, whether or not the same is specifically disclosed. In order to avoid any doubt, all compositions claimed through use of the term "comprising" may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term "consisting essentially of" excludes from the scope of any succeeding recitation any other component, step, or procedure, excepting those that are not essential to operability. The term "consisting of" excludes any component, step, or procedure not specifically delineated or listed. The term "or," unless stated otherwise, refers to the listed members individually as well as in any combination. Use of the singular includes use of the plural and vice versa. [0013] An "ethylene-based polymer" is a polyme