EP-4735246-A1 - COMPOSTABLE FILM HAVING AN IMPROVED BARRIER FOR PACKAGING

Abstract

A compostable multilayer film as well as hermetically packaged products using said compostable multilayer film. The compostable multilayer film includes a first film located on a first exterior surface (i.e., exterior of the package) the first film being selected from a PLA film, a paper, and a starch based film; a second film located on a second exterior surface (i.e., the interior of the package, contacting the product) the second film comprising a blend of PLA and PBAT; and a barrier film located between the first film and the second film. The barrier film including a barrier layer and a base film having at least a compostable layer, a delamination layer, and a support layer, wherein the delamination layer and the support layer are removed from the barrier film prior to inclusion in the compostable multilayer film. The compostable multilayer film may be suitable for extended shelf-life storage of fluid products.

Inventors

• ELIAS, Marcelo B.
• GRUETZMACHER, Ross K.
• BERBERT, OTACILIO T.

Assignees

• Amcor Flexibles North America, Inc.

Dates

Publication Date

20260506

Application Date

20230628

Claims (20)

1. 1 . A compostable multilayer film comprising: a first film located on a first surface of the compostable multilayer film, the first film selected from the group consisting of a polylactic acid (PLA) film, a paper, and a starch-based film; a second film located on a second surface of the compostable multilayer film, the second film comprising a blend of PLA and poly(butylene adipate-co- terephthalate) (PBAT); and a barrier film located between the first film and the second film, the barrier film comprising a barrier layer and a base film, the base film being a multilayer film comprising at least a compostable layer, a delamination layer positioned directly adjacent the compostable layer, and a support layer positioned directly adjacent the delamination layer, wherein the delamination layer comprises an incompatible polyolefin chemically modified to promote slight adhesion to the compostable layer but strong adhesion to the support layer, and wherein a portion of the base film comprising the delamination layer and the support is removed prior to inclusion of the barrier film in the compostable multilayer film.
2. 2. The compostable multilayer film according to claim 1 , further comprising a first adhesive layer and a second adhesive layer, the first adhesive layer located between the first film and the barrier film and the second adhesive layer located between the second film and the barrier film, and each of the first adhesive layer and the second adhesive layer comprise a compostable adhesive material.
3. 3. The compostable multilayer film according to claim 2, wherein the compostable layer comprises aPLA and the delamination layer comprises EVA.
4. 4. The compostable multilayer film according to claim 2, wherein the barrier layer is a vapor deposited metal layer formed on a surface of the compostable layer of the barrier film.
5. 5. The compostable multilayer film according to claim 1 , wherein the base film of the barrier film is a coextrusion with a first layer being the compostable layer comprising aPLA, a second layer being the delamination layer comprising EVA, and a third layer being the support layer comprising PE, and wherein the barrier layer is a vapor deposited metal layer on the first layer.
6. 6. The compostable multilayer film according to claim 1 , wherein the base film of the barrier film is a first layer being butenediol vinyl alcohol (BVOH) copolymer, a second layer being the compostable layer comprising aPLA, a third layer being the delamination layer comprising EVA, and a fourth layer being the support layer comprising PE, wherein the barrier layer is a vapor deposited metal layer on the first layer.
7. 7. The compostable multilayer film according to claim 6, wherein the second layer being the compostable layer comprises PBAT.
8. 8. The compostable multilayer film according to claim 1 , the first film comprising: a first skin layer comprising PLA, a second skin layer comprising PLA, and a core layer comprising PBAT.
9. 9. The compostable multilayer film according to claim 1 , wherein the first film is a PLA film or a starch-based film.
10. 10. The compostable multilayer film according to claim 1 , wherein the multilayer film is free from paper and cellulose.
11. 11 . The compostable multilayer film according to claim 1 , further comprising a printed indicia layer located on a surface of the first film.
12. 12. A compostable multilayer film comprising: a first film located on a first surface of the compostable multilayer film, the first film is a PLA film; a printed indicia layer located on a surface of the first film opposing the first surface of the compostable multilayer film; a second film located on a second surface of the compostable multilayer film, the second film comprising a blend of PLA and PBAT; a barrier film located between the first film and the second film, the barrier film comprising a barrier layer and a base film comprising: at least a compostable layer; a delamination layer positioned directly adjacent the compostable layer, the delamination layer comprising an incompatible polyolefin chemically modified to promote slight adhesion to the compostable layer but strong adhesion to a support layer; and the support layer positioned directly adjacent the delamination layer, wherein a portion of the base film comprising the delamination layer and the support is removed prior to inclusion of the barrier film in the compostable multilayer film; a first adhesive layer comprising a compostable adhesive material, the first adhesive layer located between the first film and the barrier layer of the barrier film; and a second adhesive layer comprising a compostable adhesive material, the second adhesive layer located between the second film and the barrier film.
13. 13. The compostable multilayer film according to claim 12, wherein the at least compostable layer comprises aPLA and the barrier layer, the delamination layer comprises EVA, and the support layer comprises PE.
14. 14. The compostable multilayer film according to claim 12, wherein the base film comprises a first layer of BVOH and the barrier layer, a second layer being the at least a compostable layer comprising aPLA, a third layer being the delamination layer comprising EVA, and the support layer being a fourth layer comprising PE.
15. 15. The compostable multilayer film according to claim 14, wherein the second layer comprises PBAT.
16. 16. The compostable multilayer film according to claim 12-14, wherein the barrier layer is a vapor deposited metal layer.
17. 17. The compostable multilayer film according to claim 12-14, wherein the barrier layer is an inorganic deposition of SiOx or AIOx.
18. 18. The compostable multilayer film according to claim 12, wherein the first film comprises: a first skin layer comprising PLA, a second skin layer comprising PLA, and a core layer comprising PBAT.
19. 19. A packaged product comprising a package comprising the compostable multilayer film according to any previous claim and a product contained within the package.
20. 20. The packaged product according to claim 19, wherein the product is a fluid.

Description

COMPOSTABLE FILM HAVING AN IMPROVED BARRIER FOR PACKAGING TECHNICAL FIELD [001 ] This disclosure is related to compostable multilayer films that are suitable for packaging products that require hermetic protection from moisture loss. More particularly, this disclosure is related to compostable multilayer films that have an improved barrier film capable of being produced in a thickness that is substantially more thin than previously disclosed structures. BACKGROUND [002] It has become increasingly desirable to design flexible packaging structures that are more sustainable. Increased sustainability may be in the form of using raw materials that are renewably resourced, such as paper or starch-based polymers. Increased sustainability may also be in the form of an end-of-life solution that is something other than waste, such as reusable or recyclable options. For flexible packaging that is used for extended shelf-life food products, it can be difficult to match the required performance properties to any of these more sustainable options. [003] In addition to the packaging design challenges, flexible packages that may hold moisture-rich food products may be very difficult to recycle given that there is typically food remnants in the package. If the food packages are small, the size of the packages also make them difficult to recycle and become potential pollutants for recycling streams (typically glass or paper). These applications become candidates for compostable solutions. Typically, these packages require shelf-life from 3 to 18 months. If compostable, the packaging should be able to fulfill well established compostable standards that require disintegration, biodegradation at industrial and home composting conditions (12 weeks at 58°C or 26 weeks at 21 °C, respectively) and that fulfill chemical characterization and ecotoxicity requirements. [004] High moisture transmission rates of compostable materials have traditionally limited their use in flexible packaging to applications with low or non-moisture barrier requirements or for rigid applications where short shelf- life is required. Examples of applications that use compostable materials are single use rigid food service containers and utensils that will be disposed of within a few hours or days of use. [005] The packaging industry has had difficulty designing compostable packaging films for long term hermetic storage of fluid (i.e., liquid) product, particularly those that are acidic or oily products. These products are particularly degrading to most compostable materials, causing loss of barrier and appearance properties in a matter of days. [006] The challenge becomes to provide a durable enough solution that resists the presence of fluid liquid, oily or acidic products and that delivers the product protection for liquid applications but that also should accomplish short times to compost according to well-known composting standards. SUMMARY [007] The developments described herein include multilayer structures that can expand the applicability of compostable materials to packages for fluid or product applications requiring extended shelf-life. In various embodiments, the solutions presented here provide for 1 ) the desired functionality for product protection preventing moisture loss and product oxidation, 2) the prevention of barrier deterioration, delamination, or chemical attack of the package during the product shelf-life, and/or 3) the enablement of biodegrading and disintegrating under industrial or home composting conditions. The compostable multilayer film may be particularly suitable for use in packaged products, enabling extended shelf-life storage of products, such as, but not limited to, fluid products. [008] Disclosed herein are compostable multilayer films having a first film located on a first surface of the compostable multilayer film, the first film selected from the group consisting of a polylactic acid (PLA) film, a paper, and a starch-based film, a second film located on a second surface of the compostable multilayer film, the second film comprising a blend of polylactic acid (PLA) polymer and poly(butylene adipate-co-terephthalate) (PBAT) polymer, and a barrier film located between the first film and the second film, the barrier film comprising a base film comprising PLA polymer, preferably of the amorphous type, and a barrier layer located on a surface of the base film. [009] Some embodiments of the compostable multilayer film further include a first adhesive layer and a second adhesive layer, the first adhesive layer located between the first film and the barrier film, and the second adhesive layer located between the second film and the barrier film. Each of the first adhesive layer and the second adhesive layer may be made of a compostable adhesive material. [010] The base film of the barrier film may have a first layer comprising aPLA (amorphous PLA) polymer, a second layer comprising ethylene vinyl acetate (EVA) polymer a