Concavo-Convex Sound Insulation Sheet for Low-Frequency Noise

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Solution Overview

Problem

Conventional sound insulation members face challenges in achieving high sound insulation performance in a low frequency band, particularly when attached to high-density materials like steel plates, and are difficult to mass-produce without molding defects.

Innovation Solution

A sound insulation sheet with a concavo-convex structure on a substrate, where convex portions are linearly arranged, and a sound insulation structure with a sealed space between the sheet and a plate material, using a retention unit to enhance sound insulation performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sound insulation sheet is made entirely of resin foam material, then it has good sound insulation performance and ease of processing, but it lacks flame retardancy

Engineering Contradiction:
Improvesound insulation performanceVSAvoidflame retardancy
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies composite materials by combining resin foam (for sound insulation) with flame-retardant particles (for flame retardancy). The sound insulation sheet comprises a resin foam body embedded with flame-retardant particles, creating a composite material that simultaneously provides both sound insulation performance and flame retardancy, resolving the contradiction between these two properties.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If flame-retardant particles are simply mixed into the resin foam, then flame retardancy is achieved, but the particles aggregate and reduce sound insulation performance

Engineering Contradiction:
Improveflame retardancyVSAvoidsound insulation performance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent uses an intermediary substance (silane-modified polymer or silicone oil) to prevent aggregation of flame-retardant particles. This intermediary acts as a dispersing agent that maintains uniform distribution of particles within the resin foam matrix, ensuring both flame retardancy and sound insulation performance are maintained without particle aggregation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the surface properties of flame-retardant particles by silane modification. This parameter change (surface treatment) prevents particle aggregation by modifying the surface energy and interaction characteristics, allowing particles to remain uniformly dispersed while maintaining their flame-retardant function and not compromising sound insulation.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If conventional mixing methods are used to incorporate flame-retardant particles, then processing is simple, but particle aggregation occurs and uniform distribution is poor

Engineering Contradiction:
Improveprocessing simplicityVSAvoidparticle distribution uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-modifying the flame-retardant particles with silane before incorporating them into the resin foam. This preliminary surface treatment ensures that particles are prepared in advance with improved dispersibility, allowing them to be uniformly distributed during the foam formation process without requiring complex additional processing steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the physical and chemical parameters of the flame-retardant particles through silane modification. This parameter change (surface modification) improves particle dispersibility and prevents aggregation during mixing, achieving uniform distribution while maintaining processing simplicity through the modified particle properties.

Inventive Principle:
Principle #35Parameter changes

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 provides a thin, lightweight sound insulation sheet and structure that effectively insulates against low-frequency sound, even on high-density materials, while avoiding molding defects and enhancing sound insulation strength.

Implementation Method 1

the flame-retardant particles have a specific heat value of 0.83 cal/g·°C or more, and a water vapor generation value of 30 mass% or more based on the total weight of the particles

Methodology Applied
Scientific EffectHeat absorption: Absorption (physical)

Implementation Method 2

a water vapor generation value of 30 mass% or more based on the total weight of the particles

Methodology Applied
Scientific EffectWater vapor generation: Evaporation

Implementation Method 3

a sound insulation sheet for a vehicle

Methodology Applied
Scientific EffectSound absorption: Acoustic Absorption

Data Source

PatentEP3951111B1Sound insulation structure
Publication Date: 2026.04.29 MITSUBISHI CHEM CORP
  • EP3951111B1 patent drawingFigure 1~2
  • EP3951111B1 patent drawingFigure 3~4
  • EP3951111B1 patent drawingFigure 5~6

AI summary

To provide a sound insulation sheet member which is excellent in sound insulation performance in a low frequency band and which has a compact configuration. A sound insulation sheet member 1 including a substrate 2 and a concavo-convex structure 3 placed on at least one surface of the substrate 2, in which the concavo-convex structure 3 is provided by repeatedly arranging a plurality of units each defined as a concavo-convex unit shape 4 including a linear convex portion 5, in one direction at substantially constant intervals on the surface of the substrate 2.