Interlayer film for laminated glass, and laminated glass

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Solution Overview

Problem

Conventional laminated glass with heat shielding performance experiences a deterioration in sound insulating properties at relatively low temperatures due to variations in ambient temperature.

Innovation Solution

An interlayer film for laminated glass with a three or more-layer structure, comprising specific layers with varying glass transition temperatures and containing heat shielding particles, which enhances sound insulation by maintaining performance in low temperature regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional interlayer film with heat shielding particles is used, then heat shielding performance is improved, but sound insulating property deteriorates in low temperature region

Engineering Contradiction:
Improveheat shielding performanceVSAvoidsound insulating property in low temperature region
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The interlayer film is divided into multiple layers with different glass transition temperatures. The first layer (with lower Tg) maintains flexibility and sound insulation at low temperatures, while the second layer (with higher Tg) provides heat shielding performance. This segmentation allows each layer to optimize its function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the glass transition temperature parameter of different layers to solve the contradiction. By setting the first layer's Tg below -30°C and the second layer's Tg above 0°C, the film maintains appropriate flexibility and damping characteristics across different temperature conditions, ensuring both sound insulation and heat shielding performance.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If interlayer film with high heat shielding performance is used, then solar transmittance is reduced, but sound insulating property varies with ambient temperature

Engineering Contradiction:
Improvesolar transmittance controlVSAvoidsound insulating property stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent uses a composite structure combining two different resin materials with distinct glass transition temperatures. This composite approach allows the interlayer film to simultaneously achieve stable sound insulation properties across temperature ranges and effective solar transmittance control through the heat shielding particles in the second layer.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If single-layer interlayer film structure is used, then manufacturing is simplified, but performance consistency across temperature ranges is poor

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidperformance consistency across temperature ranges
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The interlayer film is segmented into two distinct layers, each optimized for specific temperature ranges and functions. This segmentation improves performance consistency across temperature ranges while maintaining manufacturability through established lamination processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each layer is assigned different local qualities (glass transition temperatures) suitable for its specific function. The first layer has lower Tg for low-temperature flexibility, while the second layer has higher Tg for heat shielding, allowing each region of the film to perform optimally under different conditions.

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 interlayer film maintains a high sound insulating property in a temperature range of -10°C to 10°C, with a secondary resonance frequency difference of 60 Hz or more and a loss factor of 0.25 or more, while maintaining a solar transmittance of 50% or less.

Implementation Method 1

a loss factor at 20°C of the laminated glass X is 0.25 or more

Methodology Applied
Scientific EffectViscoelastic damping: Viscoelasticity

Implementation Method 2

enhancing the sound insulating property of laminated glass

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Implementation Method 3

containing heat shielding particles, which enhances sound insulation by maintaining performance in low temperature regions

Methodology Applied
Scientific EffectAbsorption of electromagnetic radiation: Absorption (EM radiation)

Data Source

PatentEP4001233B1Interlayer film for laminated glass, and laminated glass
Publication Date: 2025.09.10 SEKISUI CHEMICAL CO LTD
  • EP4001233B1 patent drawingFigure 1~3
  • EP4001233B1 patent drawingFigure 4
  • EP4001233B1 patent drawing

AI summary

Provided is an interlayer film for laminated glass capable of enhancing the sound insulating property of laminated glass in a relatively low temperature region. An interlayer film for laminated glass according to the present invention is an interlayer film for laminated glass having a one-layer structure or a two or more-layer structure, and when the interlayer film is sandwiched between two sheets of green glass having a thickness of 2 mm to obtain a laminated glass X with a size of 25 mm long × 300 mm wide, an absolute value of difference between a secondary resonance frequency of the laminated glass X before irradiation with xenon light and a secondary resonance frequency of the laminated glass X after irradiation with xenon light determined by a specific xenon light irradiation test is 60 Hz or more, a loss factor at 20°C of the laminated glass X is 0.25 or more, and a solar transmittance of the laminated glass X is 50% or less.