Multilayer Plastic Container EVOH Recyclability
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Solution Overview
Problem
Existing plastic containers consume large amounts of plastic, hindering environmental sustainability and recyclability, necessitating a solution for improved monomaterialization and recyclability.
Innovation Solution
A plastic container configuration with a multilayer structure, including an inner layer, inner adhesive layer, gas barrier layer, outer adhesive layer, and outer layer, with a content rate of EVOH resin at 5% by mass or less, promoting monomaterialization and enhanced recyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multilayer structure with EVOH resin is used to achieve gas barrier performance, then the barrier properties are improved, but the recyclability deteriorates due to material diversity
Solution Approach 1:
The patent changes the material composition parameter by limiting EVOH resin content to 5% by mass or less, and the thickness ratio parameter by setting the gas barrier layer thickness to be 4.0 times or more the adhesive layer thickness. This allows maintaining barrier performance while improving recyclability through monomaterialization.
Solution Approach 2:
The patent uses a composite multilayer structure consisting of polyolefin resin (inner layer), gas barrier layer (outer layer), and adhesive layers. This composite structure achieves both gas barrier performance and improved recyclability when the EVOH content is controlled at 5% or less, enabling separation and recycling of the layers.
2Strength
If the thickness of adhesive layers is increased to ensure layer bonding, then the structural integrity is improved, but the monomaterialization ratio deteriorates
Solution Approach 1:
The patent optimizes the thickness parameter by setting the adhesive layer thickness to be 1/4.0 or less of the gas barrier layer thickness. This parameter control ensures adequate bonding strength while minimizing the proportion of adhesive material, thereby improving the monomaterialization ratio.
3Reliability
If the EVOH resin content is increased to enhance gas barrier properties, then the barrier performance is improved, but the recyclability deteriorates due to reduced monomaterialization
Solution Approach 1:
The patent applies parameter change by strictly limiting the EVOH resin content to 5% by mass or less of the total container weight. This parameter control maintains sufficient gas barrier performance while maximizing the proportion of recyclable monomaterial (polyolefin resin), thereby improving overall recyclability.
Solution Approach 2:
The patent applies local quality by concentrating the gas barrier function in a dedicated outer layer with specific thickness characteristics, rather than distributing EVOH resin throughout the entire structure. This localized approach achieves barrier performance with minimal EVOH content, preserving recyclability.
Data Source
AI summary
The present invention provides a plastic container with excellent recyclability. According to the present invention, plastic container for containing a content, wherein the plastic container includes, in order from the inner surface side, an inner layer, an inner adhesive layer, a gas barrier layer, an outer adhesive layer, and an outer layer, and a content rate of EVOH resin in the plastic container is 5% by mass or less.