Thermoplastic Elastomer Network for Compression Durability
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Solution Overview
Problem
Conventional cushioning materials, such as foamed-crosslinking type urethanes, face challenges with low repeated compression durability, high costs for disposal, and environmental concerns due to poor recyclability and chemical pollution, while existing network structures fail to meet stringent durability requirements under 750 N constant load repeated compression.
Innovation Solution
A three-dimensional random loop bonded network structure using thermoplastic elastomers like polyester-based, polyolefin-based, and ethylene-vinyl acetate copolymers, with specific fiber diameter ratios and apparent densities, achieving 40% hardness retention and low residual strain under 750 N constant load repeated compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If foamed-crosslinking type urethanes are used as cushioning material, then durability is improved, but moisture and water permeability deteriorate, air permeability deteriorates, and thermal storage property increases causing humid feeling
Solution Approach 1:
The patent uses a three-dimensional random loop bonded network structure with inherent porosity. The network structure consists of interconnected loops forming void spaces that allow moisture and air permeability while maintaining mechanical durability. This porous architecture enables breathability and moisture wicking without sacrificing structural integrity.
2Reliability
If foamed-crosslinking type urethanes are used, then cushioning performance is improved, but recyclability deteriorates and disposal costs increase
Solution Approach 1:
The patent changes the material parameter from crosslinked polyurethane to thermoplastic resin, which fundamentally alters the material's recyclability. Thermoplastic resins can be melted and reformed, enabling recycling and reuse, whereas crosslinked materials cannot be remelted. This parameter change maintains cushioning performance while solving disposal and environmental issues.
3Ease of manufacture
If conventional network structures are used, then manufacturing simplicity is improved, but repeated compression durability deteriorates under 750 N constant load
Solution Approach 1:
The patent applies local quality by creating a non-uniform fiber diameter distribution within the network structure. The fiber diameter varies at different locations and orientations, with some regions having thicker fibers for load-bearing and others having thinner fibers for flexibility. This local variation in fiber properties enhances the structure's ability to withstand repeated compression while maintaining manufacturing simplicity.
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 exhibits excellent repeated compression durability, maintaining hardness and comfort over time, suitable for various applications including office chairs, vehicle seats, and impact-absorbing mats, while reducing environmental impact and disposal costs.
Implementation Method 1
forming random loops with curling treatment of a continuous linear structure including at least one thermoplastic elastomer... and by making each loop mutually contact in a molten state
Data Source
AI summary
An object of the present invention is to provide a network structure which is thus excellent in repeated compression properties. The present invention relates to a network structure comprising 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 elastomer selected from the group consisting of a polyester-based thermoplastic elastomer, a polyolefin-based thermoplastic elastomer, and an ethylene-vinyl acetate copolymer, and by making each loop mutually contact in a molten state, wherein a fiber diameter of the continuous linear structure is not less than 0.1 mm and not more than 3.0 mm, a fiber diameter of a surface layer portion of the network structure is not less than 1.05 times of a fiber diameter of an inner layer portion thereof, an apparent density is not less than 0.01 g/cm3 and not more than 0.20 g/cm3, 750 N-constant load repeated compression residual strain is not more than 15%, and 40%-compression hardness retention after 750 N-constant load repeated compression is not less than 55%.