Polyethylene Laminate Structure for Recyclable Impact-Resistant Packaging
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Solution Overview
Problem
Conventional packaging bags with high recyclability are limited by poor impact resistance, leading to potential breakage and leakage during handling and transportation.
Innovation Solution
A laminated body structure with specific MD elongation rates and polyethylene layers, including a substrate and sealant layer, optionally with an intermediate and protective layer, and adhesive layers, ensuring superior recyclability and impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a laminated body with multiple resin materials and paper or metallic materials is used to achieve functional requirements, then the packaging performance is improved, but the recyclability decreases because the percentage of principal resin falls below 90 mass%
Solution Approach 1:
The patent changes the material composition parameter by using polyethylene for both the substrate layer and sealant layer, ensuring the principal resin content is 90 mass% or greater. This parameter change enables the packaging to meet recyclability criteria while maintaining necessary packaging functions through optimized layer structure and thickness ratios.
2Ease of manufacture
If a laminated body with high recyclability (90 mass% or greater polyethylene) is used, then the recyclability is improved, but the impact resistance deteriorates causing breakage and leakage during handling and transportation
Solution Approach 1:
The patent applies local quality by differentiating the properties of substrate layer and sealant layer. The substrate layer has specific MD elongation rates (0.5-3.0% at 70°C, 2.0-5.0% at 90°C) optimized for impact resistance, while the sealant layer is optimized for sealing function. This localized optimization allows the entire structure to achieve both high recyclability and superior impact resistance.
Solution Approach 2:
The patent uses composite material structure with polyethylene substrate layer and polyethylene sealant layer, where each layer has optimized thickness and properties. The composite structure leverages the advantages of polyethylene material while distributing functional requirements across layers, achieving both recyclability (90 mass% or greater polyethylene) and impact resistance through proper layer design.
3Strength
If the substrate layer has high elongation rate to improve impact resistance, then the impact resistance is improved, but the structural stability deteriorates
Solution Approach 1:
The patent optimizes the MD elongation rate parameter within specific ranges (0.5-3.0% at 70°C, 2.0-5.0% at 90°C) to achieve the right balance. This parameter optimization ensures the substrate layer has sufficient elongation for impact resistance while maintaining structural stability for practical use, resolving the contradiction between flexibility and stability.
Data Source
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AI summary
A laminated body having a structure in which a substrate layer and a sealant layer are laminated in this order, wherein the substrate layer and the sealant layer include polyethylene, and the substrate layer has machine direction (MD) elongation rates of (i) 0.5 to 3.0% when a tension of 50 N/m is applied at 70 °C and (ii) 2.0 to 5.0% when a tension of 50 N/m is applied at 90 °C, or a tensile elastic modulus of the substrate layer in a machine direction is 800 to 2000 MPa at 23 °C.