Multilayer Packaging Structure Maintaining Peel Strength Under Low Humidity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Starch resin layers used in multilayer structures for packaging containers are prone to reduced peel strength due to moisture absorption and contraction, especially under low-humidity conditions, leading to compromised barrier properties.
Innovation Solution
A multilayer structure comprising a starch layer, an adhesive layer with a thermoplastic resin of density 0.920 g/cm3 or lower and an acid value of 0.3 mgKOH/g or higher, and a base material layer with a tensile elastic modulus of 100 MPa or higher, which maintains peel strength under low-humidity conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a starch resin layer is used in a multilayer structure, then gas barrier properties and biodegradability are improved, but peel strength is reduced under low-humidity conditions due to moisture absorption and contraction
Solution Approach 1:
The patent applies parameter changes by carefully controlling the water content in the starch resin layer (5-25% by mass) and the thickness ratio between the starch resin layer and the total multilayer structure (30-80% by mass). These parameter optimizations allow the starch resin layer to maintain adequate peel strength while preserving its gas barrier properties and biodegradability.
Solution Approach 2:
The patent uses composite materials by combining the starch resin layer with other compatible biodegradable resin layers (such as PLA, PBAT, or PHA) to create a multilayer structure. This composite approach enhances the overall peel strength and structural integrity while maintaining the gas barrier properties and biodegradability of the starch-based components.
2Reliability
If the starch content in the resin layer is increased, then biodegradability and gas barrier properties are improved, but the layer becomes more sensitive to humidity changes and contracts more, reducing peel strength
Solution Approach 1:
The patent applies parameter changes by optimizing the starch content within a specific range (20-98% by mass) and controlling the water content (5-25% by mass). This balanced composition allows the starch-rich layer to maintain high biodegradability and gas barrier properties while minimizing excessive contraction under low-humidity conditions.
Solution Approach 2:
The patent applies local quality by creating a multilayer structure where different layers have different compositions and functions. The starch resin layer provides gas barrier and biodegradability, while adjacent layers with different resin compositions provide dimensional stability and peel strength, compensating for the starch layer's sensitivity to humidity changes.
3Reliability
If a water-resistant material layer is added to protect the starch layer, then barrier properties are improved, but the complexity of the multilayer structure increases
Solution Approach 1:
The patent applies universality by using biodegradable resin layers that serve multiple functions simultaneously. The same layers provide water resistance, maintain gas barrier properties, ensure biodegradability, and provide structural integrity, eliminating the need for separate specialized water-resistant layers and reducing overall structure complexity.
Solution Approach 2:
The patent uses composite materials by combining biodegradable resins with different functional properties in a multilayer configuration. These composite layers work synergistically to provide water resistance, gas barrier properties, and structural stability without requiring excessive numbers of separate layers, thus managing complexity while achieving multiple protective functions.
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 proposed multilayer structure effectively maintains peel strength and barrier properties even when stored under low-humidity conditions, preventing the deterioration of starch resin layers and ensuring the integrity of packaging containers.
Implementation Method 1
a starch resin layer absorbs/desorbs moisture and thereby expands/contracts by at least several % due to the effects of external temperature and humidity
Implementation Method 2
an adhesive layer (B), wherein a material constituting the adhesive layer (B) comprises a thermoplastic resin
Data Source
AI summary
The present invention relates to a multilayer structure including a starch layer (A), an adhesive layer (B), and a base material layer (C) in the order mentioned. In this multilayer structure, a material constituting the starch layer (A) comprises a starch and water; a material constituting the adhesive layer (B) comprises a thermoplastic resin having a density of 0.920 g/cm3 or lower and has an acid value of 0.3 mgKOH/g or higher; and the base material layer (C) is a layer having a tensile elastic modulus of 100 MPa or higher.