Recessed Resin Foam Particles for Thin Sound-Absorbing Laminates
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Solution Overview
Problem
Resin foam materials struggle to achieve a balance between sound absorption and mechanical strength due to their cell structure, with closed cell foams offering rigidity but poor sound absorption and open cell foams providing sound absorption but lacking rigidity, limiting their use as structural materials.
Innovation Solution
Resin foam particles with a recessed external part, specifically through holes or recesses, are thermally fused to create a resin foam shaped product with continuous pores, using a thermoplastic resin with controlled surface tension and glass-transition temperature, resulting in a freestanding sound absorbing material with enhanced mechanical strength and sound absorption performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water-soluble polymer is used as a foaming agent, then the foaming process is simple and inexpensive, but the resin particles aggregate during drying and the foam structure becomes non-uniform
Solution Approach 1:
The patent uses a composite foaming agent system combining water-soluble polymer (as foam stabilizer) and organic solvent (as blowing agent). This composite approach allows the water-soluble polymer to stabilize foam bubbles while the organic solvent provides controlled gas expansion, achieving both simple processing and uniform foam structure without requiring complex equipment.
2Duration of action of stationary object
If resin particles are dried to remove foaming agent, then the foam structure is formed, but the particles aggregate due to surface adhesion
Solution Approach 1:
The patent introduces a surface-modified resin particle as an intermediary substance. These particles have reduced surface adhesion properties that prevent aggregation during drying while maintaining foam structure formation. The modified particles act as spacers that maintain particle separation without interfering with the foaming mechanism.
3Manufacturing precision
If the resin particles are made smaller for better coating properties, then the coating uniformity improves, but the aggregation during drying becomes more severe
Solution Approach 1:
The patent changes the surface energy parameters of the resin particles through surface modification. This parameter change reduces surface adhesion forces that cause aggregation, allowing small particles to maintain dispersion stability during drying while preserving their fine size for good coating uniformity and penetrability.
4Device complexity
If conventional foam molding is used, then the production process is simple, but the foam density is non-uniform and contains defects
Solution Approach 1:
The patent performs preliminary surface modification of resin particles before foaming. This preliminary action reduces surface adhesion and prevents aggregation during the subsequent simple drying process, allowing conventional foam molding equipment to produce uniform foam density without requiring complex control systems.
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 resin foam shaped product exhibits excellent sound absorption performance and mechanical strength, enabling its use as a structural material while maintaining high sound insulation, even in thin configurations, and can be integrated into laminates for improved sound absorption.
Implementation Method 1
a blowing agent (afoaming agent) comprising an organic solvent
Implementation Method 2
a foam stabilizer comprising a water-soluble polymer
Implementation Method 3
When the thus-obtained resin particles are dried, a resin foam molded body having a uniform foam structure
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Provided are resin foam particles that enable shaping of a sound absorbing member having excellent sound absorption performance through a resin foam shaped product. Also provided is a laminate that includes a resin foam shaped product as a base material and with which high sound absorption performance can be obtained even when the laminate is a thin material. The resin foam particles contain a resin and have a recessed external part. A ratio ρ0/ρ1 of density of the resin ρ0 and true density ρ1 of the resin foam particles is 2 to 20, and a ratio ρ1/ρ2 of true density ρ1 of the resin foam particles and bulk density ρ2 of the resin foam particles is 1.5 to 4.0.