Expanded Beads Molded Article with Block Copolymer for Lightweight High Elasticity
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Solution Overview
Problem
Existing expanded polyolefin resin beads lack both lightweight properties and sufficient repulsion elasticity for applications such as seat cushioning and shock-absorbing materials, with thermoplastic polyurethane and ethylene-α-olefin copolymer-based solutions falling short in achieving optimal density and modulus of repulsion elasticity.
Innovation Solution
A block copolymer composed of a polyethylene block and an ethylene-α-olefin copolymer block is used to create an expanded beads molded article with a density of 30 kg/m3 to 150 kg/m3 and a modulus of repulsion elasticity of 60% or more, featuring a multi-block structure, specific cell wall thickness, and a high closed cell ratio, which enhances both lightweight properties and repulsion elasticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermoplastic polyurethane expanded beads are used to improve repulsion elasticity, then the modulus of repulsion elasticity is improved, but the density increases and lightweight property deteriorates
Solution Approach 1:
The patent uses composite expanded beads made from a blend of polyolefin resin (80-95 wt%) and thermoplastic polyurethane resin (5-20 wt%). This composite structure allows the material to achieve the lightweight properties of polyolefin while incorporating the superior repulsion elasticity of thermoplastic polyurethane, thereby resolving the contradiction between weight and elasticity.
Solution Approach 2:
The patent optimizes the density of the expanded beads to a specific range (80-150 kg/m3) and controls the modulus of repulsion elasticity to be 60% or more. By precisely controlling these parameters within defined ranges, the invention achieves both lightweight property and high repulsion elasticity simultaneously.
2Weight of moving object
If polyolefin resin expanded beads are used to reduce density and achieve lightweight property, then the density is reduced, but the modulus of repulsion elasticity decreases
Solution Approach 1:
The patent creates a composite material system where polyolefin resin serves as the base matrix providing lightweight properties, while thermoplastic polyurethane resin acts as a reinforcing phase enhancing repulsion elasticity. This composite approach allows simultaneous achievement of low density and high elasticity.
Solution Approach 2:
The patent specifies that the expanded beads should have a density of 80-150 kg/m3 and a modulus of repulsion elasticity of 60% or more. By controlling these parameters within these ranges, the invention overcomes the limitation of conventional polyolefin beads that lack sufficient repulsion elasticity.
3Weight of moving object
If ethylene-α-olefin copolymer expanded beads with density of 150 kg/m3 or less are used to improve lightweight property, then the density is reduced, but further lightweight material is still demanded and repulsion elasticity may be insufficient
Solution Approach 1:
The patent employs a composite resin system combining polyolefin and thermoplastic polyurethane in specific proportions. This composite structure enables the expanded beads to achieve density below 150 kg/m3 while maintaining or enhancing repulsion elasticity, surpassing the performance of conventional single-material expanded beads.
Solution Approach 2:
The patent defines specific parameter ranges: density of 80-150 kg/m3 (further lightweight than conventional 150 kg/m3 or more) and modulus of repulsion elasticity of 60% or more. These controlled parameters ensure both lightweight property and sufficient repulsion elasticity are achieved simultaneously.
Data Source
AI summary
The present invention relates to an expanded beads molded article containing a block copolymer of a polyethylene block and an ethylene-α-olefin copolymer block and having a density of 30 kg/m3 or more and less than 150 kg/m3 and a modulus of repulsion elasticity of 60% or more. The sole member of the present invention includes the expanded beads molded article of the present invention.