Multilayer Ionomer Interlayer for Acoustic Damping and Flexural Strength

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Solution Overview

Problem

Conventional laminated glass interlayers fail to provide a desirable combination of sound insulating, flexural strength, stiffness, and optical properties, especially under external load influences and over a broad temperature range, leading to instability in sound insulating performance and increased weight due to thickness requirements.

Innovation Solution

A multilayer interlayer comprising a first and second thermoplastic resin skin layer with an acoustic damping layer in between, where the acoustic damping layer is a thermoplastic elastomer resin, and the ionomer resin includes copolymerized units of ethylene, α,β-unsaturated carboxylic acid, and its derivatives, providing a ratio of total thickness of the acoustic damping layer to skin layers of 1/1 or less.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the thickness of glass is increased to enhance sound insulating effect, then sound insulating properties are improved, but weight increases

Engineering Contradiction:
Improvesound insulating propertiesVSAvoidweight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The interlayer is divided into multiple functional layers: outer skin layers made of ionomer resin providing strength and stiffness, and an inner acoustic damping layer made of thermoplastic elastomer providing sound insulation. This segmentation allows each layer to specialize in its function, achieving good sound insulation with thinner overall structure, thus reducing weight compared to using thicker glass alone.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If a sound dampening interlayer is laminated between glass sheets to enhance sound insulating effect, then sound insulating properties are improved, but flexural strength and stiffness deteriorate

Engineering Contradiction:
Improvesound insulating propertiesVSAvoidflexural strength and stiffness
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

Different regions of the interlayer structure have different properties: the outer skin layers are made of ionomer resin with high strength and stiffness to provide structural support, while the inner acoustic damping layer is made of thermoplastic elastomer with high damping properties for sound insulation. This local differentiation of material properties allows the interlayer as a whole to provide both sound insulation and structural strength.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The interlayer uses a composite structure combining ionomer resin (for strength and stiffness) with thermoplastic elastomer (for acoustic damping). This composite material approach allows the interlayer to simultaneously provide structural support and sound insulation functions, resolving the contradiction between sound insulation performance and mechanical strength.

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If conventional interlayer materials are used to achieve good sound insulation, then sound dampening properties are improved, but optical properties and adhesion deteriorate

Engineering Contradiction:
Improvesound dampening propertiesVSAvoidoptical properties and adhesion
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The outer skin layers use ionomer resin which provides excellent optical transparency and strong adhesion to glass, while the inner acoustic damping layer uses thermoplastic elastomer which provides sound dampening properties. This local differentiation ensures that the materials responsible for optical and adhesion functions have superior properties in those areas, while the damping layer focuses on acoustic performance.

Inventive Principle:
Principle #3Local quality

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 achieves excellent sound insulating characteristics, flexural strength, and stiffness, allowing for weight reduction while maintaining strength and stability, with improved sound insulating performance across a broad temperature range and reduced sensitivity to high-frequency sound loss.

Implementation Method 1

the interlayer film may also have ability of converting vibration energy into heat energy, thereby absorbing the vibration energy

Methodology Applied
Scientific EffectVibration energy conversion to heat energy: Viscoelasticity

Implementation Method 2

these types of ionomers have excellent flexural strength and adhesion to glass properties

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3455070B1Multilayer interlayer and glass laminate
Publication Date: 2020.11.11 KURARAY AMERICA INC
  • EP3455070B1 patent drawingFigure 1~2
  • EP3455070B1 patent drawingFigure 3
  • EP3455070B1 patent drawingFigure 4~5

AI summary

A multilayer interlayer containing a specified ionomer skin layer and an acoustic damping intermediate layer, and laminate containing such interlayer are provided, wherein the laminate has a desirable combination of sound insulating, flexural strength and optical properties suitable for use in transportation and architectural end uses.