Composite Seat Core Material Bonding Strength
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Solution Overview
Problem
The existing laminate production methods for vehicular seat elements using polyurethane foam and thermoplastic resin foams suffer from inadequate bonding strength, leading to delamination issues and deformation, which affect the comfort and durability of the seat.
Innovation Solution
A composite seat core material is developed, comprising a foamed molded substrate of fusion-bonded thermoplastic resin expanded beads without through-holes and a connecting member with interconnected void spaces, allowing for improved bonding with a polyurethane foam pad by impregnation and foaming within the void spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a polyurethane foam cushioning layer is laminated to a thermoplastic resin foamed body substrate layer, then weight reduction and composite properties are achieved, but adhesion property is poor and delamination occurs
Solution Approach 1:
The surface of the thermoplastic resin foamed body is heated before the polyurethane foam is applied, softening the surface to create undulations that improve adhesion. This preliminary surface treatment prepares the substrate to better bond with the cushioning layer before the bonding process occurs.
Solution Approach 2:
The thermoplastic resin foamed body has a cellular porous structure that allows the polyurethane foam to penetrate and interlock with the substrate. The void spaces in the foamed body enable mechanical interlocking, significantly improving the bonding strength between layers.
2Strength
If the surface of thermoplastic resin expanded beads is heated to soften and expand the beads to form undulations, then adhesion property is improved, but bonding strength is not fully satisfactory and delamination still occurs
Solution Approach 1:
The patent combines multiple surface treatment methods: heating to soften and expand beads forming undulations, plus creating a porous cellular structure. This combination of surface undulations and porous structure allows the polyurethane foam to both mechanically interlock and chemically bond, significantly improving delamination resistance.
Solution Approach 2:
The invention creates a composite interface structure where the thermoplastic resin foamed body with cellular structure is bonded to the polyurethane foam layer. The composite nature of the interface, combining porous thermoplastic resin with polyurethane foam, provides both mechanical interlocking and adhesive bonding for superior reliability.
3Strength
If polyurethane foam is impregnated into void spaces of expanded beads molded body, then adhesion property is significantly improved, but deformation such as warp occurs depending on density
Solution Approach 1:
The patent optimizes the density parameter of the thermoplastic resin foamed body to balance adhesion and deformation. By controlling the density within a specific range, the material achieves sufficient porosity for foam impregnation and bonding while maintaining structural rigidity to minimize warping and deformation during the foaming process.
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 solution enhances bonding strength, suppresses delamination and deformation, and maintains excellent cushioning properties and rigidity in the vehicular seat element.
Implementation Method 1
a liquid raw material for forming a polyurethane foam is filled in the mold cavity in which the above member has been disposed, and is caused to foam to prepare a cushioning layer
Implementation Method 2
part of the polyurethane foam is impregnated, foamed and solidified within the void spaces that are present on a surface side thereof
Implementation Method 3
that region of a surface of an expandable thermoplastic resin expanded beads foamed body which is to be contacted by a polyurethane foam layer, is heated at a temperature that is at least 80% of the softening temperature of the foamed body to soften and expand the expandable resin beads
Implementation Method 4
heated at a temperature that is at least 80% of the softening temperature of the foamed body to soften and expand the expandable resin beads which constitute the contact region
Implementation Method 5
a foamed molded substrate that comprises a multiplicity of first thermoplastic resin expanded beads which are fusion-bonded to each other and free of through-holes
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A composite seat core material (1) including a substrate (2) that is formed of thermoplastic resin expanded beads which are free of through-holes and fusion-bonded to each other, and a connecting member (3) that is formed of expanded beads having through-holes and fusion-bonded to each other and that has interconnected void spaces which communicate with the outside. The connecting member is integrally bonded to the substrate in such a state that a part of an outer surface (3a) of the connecting member is exposed on an upper surface (1a) of the composite seat core material. A seat element (5) has a polyurethane foam pad (4) laminated on the upper surface of (1a) of the composite seat core material (1).