Amcor’s Compostable Multilayer Film Innovation for Liquid Food Products

The global packaging industry is increasingly focusing on sustainability, driven by consumer demand and environmental considerations. Amcor’s latest patent pending innovation addresses a crucial gap in sustainable flexible packaging by introducing a compostable multilayer film designed for fluid products requiring extended shelf life. This breakthrough not only meets functional requirements but also adheres to stringent compostability standards, paving the way for environmentally friendly solutions in packaging.

The Challenges in Compostable Packaging

Conventional packaging for moisture-rich, acidic, or oily food products relies heavily on non-compostable materials due to their superior durability and barrier properties. These packages often pose recycling challenges, especially when food remnants are present or when the packages are too small to process effectively. Compostable materials, while sustainable, have historically lacked the robustness needed for long-term storage and protection against chemical degradation caused by fluid or acidic contents.

Amcor’s Solution: A Multilayer Approach

Amcor’s compostable multilayer film tackles these challenges head-on by leveraging advanced material science. This innovation provides a unique combination of durability, barrier performance, and compostability. Key features of the film include:

1. Layered Composition:

   • Outer Layer: Made from compostable materials like polylactic acid (PLA), paper, or starch-based polymers.

   • Inner Layer: A blend of PLA and poly(butylene adipate-co-terephthalate) (PBAT) to provide flexibility and strength.

   • Barrier Film: Positioned between the inner and outer layers, consisting of:

     • A base film of amorphous PLA (aPLA) or similar compostable polymers.

     • A barrier layer using vapor-deposited metals or inorganic materials (e.g., SiOx or AlOx) to prevent moisture loss and oxidation.

2. Adhesive Layers:

   • Compostable adhesive materials ensure the integrity of the multilayer structure while maintaining overall compostability.

3. Delamination Layer:

   • A strategically designed ethylene vinyl acetate (EVA) layer enables efficient separation of non-compostable components during production, ensuring the final product adheres to compostability standards.

Functional Benefits

Amcor’s compostable multilayer film excels in three critical areas:

1. Extended Shelf Life: The barrier properties effectively prevent moisture loss and product oxidation, ensuring the freshness of fluid or acidic products.

2. Chemical Resistance: The multilayer design resists degradation caused by acidic or oily contents, preserving the packaging’s structural integrity throughout its lifespan.

3. Compostability: The film complies with industrial and home composting standards, disintegrating within 12 weeks at 58°C or 26 weeks at 21°C. It also meets chemical characterization and ecotoxicity requirements.

Application Potential

This compostable film is particularly suited for:

• Packaging for fluid products, including acidic beverages and sauces.

• Food applications requiring shelf lives between 3 to 18 months.

• Small-format packaging solutions that often end up as contaminants in conventional recycling streams.

Testing the Films

Amcor tested multiple film combinations under accelerated conditions (100°F/20% RH), simulating months of regular storage. Key results:

• Moisture Barrier: Their achieved a moisture vapor transmission rate (MVTR) of 0.817, compared to a significantly higher rate of 4.945 for a comparative film lacking the second layer.

• Shelf-Life Integrity: While comparative films failed within two weeks, with visible metal corrosion and delamination, Amcor’s films maintained barrier integrity for over 7 months, even with acidic and oily products like ketchup and mustard.

A Step Toward a Circular Economy

The development of these films showcases a future where small-format, fluid-containing packages can be fully compostable without sacrificing performance. The research demonstrates that it is possible to provide both oxygen and moisture barriers through the thoughtful combination of compostable materials.

This advancement paves the way for industries to reduce waste while maintaining product quality and shelf life, a critical step toward a circular economy. With Amcor’s multilayer compostable films, sustainability and performance are no longer mutually exclusive but complementary.