Starch Gas Barrier Laminate for Food Packaging
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Solution Overview
Problem
Existing food packaging laminates face challenges in achieving a balance between gas barrier properties, adhesive strength, and repulpability, with previous solutions either compromising on gas barrier performance or repulpability due to the use of adhesives.
Innovation Solution
A laminate comprising a gas barrier layer made of modified starch with an average amylose content of 45% or more and a water-soluble polymer, such as polyvinyl alcohol, adjacent to a substrate, which enhances both gas barrier properties and repulpability without the need for adhesives, achieving a biodegradation level of 80% or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an adhesive is used to secure adhesive strength between the substrate and starch layer, then adhesive strength is improved, but repulpability deteriorates
Solution Approach 1:
The invention extracts and eliminates the adhesive component from the laminate structure. By directly laminating the starch layer onto the substrate without any adhesive interlayer, the patent removes the source of repulpability problems while maintaining adequate adhesive strength through direct contact and bonding between the starch layer and substrate.
Solution Approach 2:
The invention merges the adhesive function into the starch layer itself. The starch layer is designed to provide both the barrier functionality and the adhesive bonding to the substrate, eliminating the need for a separate adhesive layer. This integration allows the starch layer to serve multiple functions simultaneously.
2Reliability
If a laminate structure is created with multiple layers, then gas barrier property is improved, but repulpability deteriorates
Solution Approach 1:
The invention applies local quality by creating a localized barrier layer with specific properties. The starch layer is formulated with high amylose content (45% or more) to provide enhanced gas barrier properties in the specific region where it is applied, while the rest of the packaging structure maintains repulpability. This localized approach allows the barrier function to be concentrated where needed without compromising overall repulpability.
3Ease of manufacture
If starch content is increased to improve repulpability, then environmental load reduction is improved, but gas barrier property deteriorates
Solution Approach 1:
The invention applies parameter changes by modifying the molecular structure and composition of the starch. Specifically, it uses starch with high amylose content (45% or more) and controls the degree of substitution or modification parameters to achieve both high repulpability and excellent gas barrier properties. This parameter optimization allows the starch to exhibit dual functionality that would not be achievable with conventional starch compositions.
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 exhibits superior gas barrier properties, adhesive strength, and repulpability, making it suitable for food packaging while reducing environmental impact by allowing for easier recycling.
Implementation Method 1
To impart a gas barrier property (especially, oxygen barrier property) to a packaging material is an important function for protecting various products to be packaged from degradation due to gas
Implementation Method 2
adjusting a degree of biodegradation of the laminate to 80% or more
Data Source
AI summary
A laminate comprising: a gas barrier layer (I) comprising a modified starch (A) having an average amylose content of 45% by mass or more and a water-soluble polymer (B); and a substrate (II) adjacent to the gas barrier layer (I), wherein the laminate exhibits a degree of biodegradation of 80% or more in a biodegradability test in accordance with ISO 14855-1.