Compostable Laminate Resolving Gas and Moisture Barrier Trade-offs

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Solution Overview

Problem

Existing compostable packaging materials face challenges in balancing moisture resistance, gas barrier properties, rigidity, weldability, and transparency, with cellulose films offering high gas barrier but low moisture resistance and transformed biodegradable films providing water resistance but low rigidity.

Innovation Solution

A stratified sheet laminate composed of a 20 µm to 50 µm thick biodegradable polymer layer, such as a mixture of PLA, PCL, and PBSA, combined with a 19 µm to 23 µm thick cellulose film using a water dispersion of polyester polyurethane elastomer glue, ensuring high gas and water barrier properties and rigidity, while maintaining compostability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cellulose film is used for packaging, then gas barrier properties are improved, but moisture resistance deteriorates

Engineering Contradiction:
Improvegas barrier propertiesVSAvoidmoisture resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies composite materials by combining cellulose film with transformed biodegradable plastic film in a laminated structure. The cellulose film layer provides excellent gas barrier properties, while the transformed biodegradable plastic film layer contributes water and moisture resistance, creating a composite material that achieves both requirements simultaneously.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If transformed biodegradable film is used for packaging, then moisture resistance is improved, but rigidity deteriorates

Engineering Contradiction:
Improvemoisture resistanceVSAvoidrigidity
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent uses composite materials where the transformed biodegradable plastic film provides moisture resistance while the cellulose film layer compensates for rigidity requirements. The laminated composite structure allows each material to contribute its strengths, achieving both moisture resistance and adequate rigidity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent segments the packaging film into two distinct functional layers: a cellulose film layer for gas barrier and rigidity, and a transformed biodegradable plastic film layer for moisture resistance. This segmentation allows each layer to optimize its specific function without compromising the other properties.

Inventive Principle:
Principle #1Segmentation

3Reliability

If multilayer laminate is used to improve barrier properties, then gas and water barrier properties are improved, but device complexity increases

Engineering Contradiction:
Improvebarrier propertiesVSAvoidlaminate structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a simple two-layer composite structure consisting of cellulose film and transformed biodegradable plastic film. This minimal multilayer design achieves the required gas and water barrier properties without excessive complexity, maintaining ease of manufacture and processing.

Inventive Principle:
Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The laminate achieves desired market features of good rigidity, transparency, and high barrier properties for liquids and gases, ensuring effective packaging while being fully compostable and easy to dispose of without separation from the product.

Implementation Method 1

The layers being connected to each other by glue constituting a water dispersion of a polyester polyurethane elastomer with a hardener

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP3626446B1Compostable material, in particular intended for packaging, and method of producing compostable material
Publication Date: 2022.10.12 SILBO SP ZOO
  • EP3626446B1 patent drawingFigure 1

AI summary

A biodegradable material in the form of a stratified sheet comprising a combination of film sheets made of compostable materials comprises at least two laminated layers of film sheets, where at least one layer constitutes a plastic sheet with at least one biodegradable polymer generated by a chemical or biocatalytic transformation, at least the second layer constitutes a sheet of cellulose film, the layers being connected to each other by glue constituting a water dispersion of a polyester-polyurethane elastomer with a hardener. A method for producing a compostable material involving laminated connection of film sheets by means of glue, in which at least one sheet of plastic film of at least one chemically or biocatalytically transformed biodegradable polymer is combined in a continuous process with at least one sheet of cellulose film, where the plastic sheet of a transformed polymer is unwound from a roller, and subsequently it is covered with previously prepared glue constituting a combination of a water dispersion of a polyester-polyurethane elastomer with a hardener, in an amount of 2.5-3.0 g/m2, it is subsequently driven through a drying tunnel and subjected to temperature within a range of 90°C - 130°C and infrared radiation; subsequently, a sheet of cellulose film unwound from a roller is applied; subsequently, the combined films are driven through a set of pressure rollers and wound onto a roller.