Polyethylene Multilayer Packaging for Strength and Recyclability
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Solution Overview
Problem
Existing packaging materials with high resin content do not meet recyclability standards due to multiple resin components, and those with sufficient strength, such as stretched polyethylene films, are prone to breaking under impact.
Innovation Solution
A multilayer body comprising a base layer of stretched polyethylene, an intermediate layer of unstretched polyethylene, and a heat seal layer, all made of polyethylene, with specific adhesion layers and a gas barrier layer, ensuring a polyethylene content of 90% or more, enhancing strength and recyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a packaging material is made with multiple resin materials to improve performance, then the functional properties are enhanced, but the recyclability decreases because the proportion of main resin falls below 90% by mass
Solution Approach 1:
The packaging material is divided into multiple functional layers (base layer, intermediate layer, heat seal layer, adhesive layers, gas barrier layer), where each layer has a specific function. The base layer and heat seal layer are both made of polyethylene to maintain high recyclability, while other layers provide necessary functional properties.
Solution Approach 2:
Different layers have different material compositions tailored to their specific functions: the base layer uses stretched polyethylene for strength, the intermediate layer uses unstretched polyethylene for flexibility, the heat seal layer provides sealing functionality, and the gas barrier layer provides barrier properties. This local optimization allows the overall structure to achieve high recyclability while maintaining functional performance.
2Strength
If a stretched polyethylene film is used as the base layer to improve strength, then the packaging strength is enhanced, but the film becomes prone to breaking under impact
Solution Approach 1:
The base layer is constructed as a composite structure combining stretched polyethylene (for strength) with an intermediate layer of unstretched polyethylene (for impact resistance). This composite approach allows the packaging material to simultaneously achieve high strength and good impact resistance by leveraging the complementary properties of different material configurations.
Data Source
AI summary
This multilayer body is provided with a base layer, an intermediate layer, a heat seal layer, a first adhesive layer that is provided between the base layer and the intermediate layer, and a second adhesive layer that is provided between the intermediate layer and the heat seal layer. The base layer, the intermediate layer, and the heat seal layer are configured to include polyethylene. In a case where the base layer is a stretched polyethylene film, the intermediate layer is an unstretched polyethylene film, and in a case where the intermediate layer is a stretched polyethylene film, the base layer is an unstretched polyethylene film. The proportion of polyethylene in the multilayer body is 90% by mass or more.