3D Random Loop Network Structure for Repeated Compression Durability

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Solution Overview

Problem

Conventional foamed-crosslinking type urethanes used in cushioning materials face issues such as poor moisture and air permeability, thermal storage problems, difficulty in recycling, and environmental concerns like pollution and landfill stabilization, while network structures struggle to balance low repeated compression residual strain and high hardness retention.

Innovation Solution

A three-dimensional random loop bonded network structure made from thermoplastic elastic resins like polyolefin-based thermoplastic elastomers, ethylene-vinyl acetate copolymers, or polyurethane-based thermoplastic elastomers, with specific properties like 50%-constant displacement repeated compression residual strain below 15% and 85% compression hardness retention, achieved through controlled heat treatment and fusion processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If foamed-crosslinking type urethanes are used as cushioning material, then durability is improved, but moisture-water-permeability and air-permeability deteriorate

Engineering Contradiction:

ImprovedurabilityVSAvoidmoisture-water-permeability and air-permeability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a network structure with inherent porosity formed by randomly arranged continuous linear structures. This porous configuration allows moisture and air to permeate through the material while maintaining durability, eliminating the need for foam structures that block permeability.

Inventive Principle:

Principle #31Porous materials

2Reliability

If foamed-crosslinking type urethanes are used, then cushioning performance is improved, but recyclability deteriorates

Engineering Contradiction:

Improvecushioning performanceVSAvoidrecyclability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the material parameter from crosslinked urethane (thermoset, non-recyclable) to thermoplastic elastomer (thermoplastic, recyclable). The thermoplastic nature allows the material to be melted and reformed, enabling recycling while maintaining cushioning performance through the network structure design.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conventional network structures are designed for low repeated compression residual strain, then durability is improved, but hardness retention after repeated compression deteriorates

Engineering Contradiction:

Improverepeated compression residual strainVSAvoidhardness retention

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by creating a heterogeneous network structure where continuous linear structures of varying fineness (100-60000 dtex) are randomly distributed. This random arrangement with diverse local properties allows the structure to distribute compression forces effectively, maintaining both low residual strain and high hardness retention.

Inventive Principle:

Principle #3Local quality

4Ease of operation

If network structure is designed for low-repulsion characteristics, then comfort is improved, but high-repulsion characteristics cannot be achieved

Engineering Contradiction:

ImprovecomfortVSAvoidhigh-repulsion characteristics

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent creates a dynamic cushioning material where the network structure can adapt its repulsion characteristics. The continuous linear structures can deform and recover dynamically, allowing the same material to provide both low-repulsion comfort for prolonged sitting and high-repulsion support for impact absorption, depending on the applied load and duration.

Inventive Principle:

Principle #15Dynamics

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 network structure provides excellent repeated compression durability, high hardness retention, and high-repulsion characteristics suitable for various applications, including office chairs, vehicle seats, and impact absorption mats, with reduced environmental impact.

Implementation Method 1

making each loop mutually contact in a molten state

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

a three-dimensional random loop bonded structure obtained by forming random loops with curling treatment of a continuous linear structure

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2966206B1Net-shaped structure having excellent compression durability

Publication Date: 2018.11.28 TOYOBO CO LTD

Figure 1

AI summary

The present invention provides a network structure having excellent repeated compression durability, a low repeated compression residual strain and a high hardness retention after repeated compression. A network structure made of a three-dimensional random loop bonded structure obtained by forming random loops with curling treatment of a continuous linear structure including at least one thermoplastic elastic resin selected from the group consisting of a polyolefin-based thermoplastic elastomer, an ethylene-vinyl acetate copolymer, a polyurethane-based thermoplastic elastomer and a polyamide-based thermoplastic elastomer, the continuous linear structure having a fineness of not less than 100 dtex and not more than 60000 dtex, and by making each loop mutually contact in a molten state, wherein The network structure has an apparent density of 0.005 g/cm3 to 0.20 g/cm3, a 50%-constant displacement repeated compression residual strain of not more than 15%, and a 50%-compression hardness retention after 50%-constant displacement repeated compression of not less than 85%.