Laminated Glass Interlayer Composition for Positional Stability

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Solution Overview

Problem

Conventional interlayer films for laminated glass often experience positional displacement between glass members during the production process, particularly when heated and pressurized in an autoclave, leading to alignment issues in laminated glass manufacturing.

Innovation Solution

An interlayer film containing a thermoplastic resin and a plasticizer, with specific birefringence indices and a glass transition temperature of 33°C or less, is used to prevent positional displacement between glass members by ensuring proper alignment and bonding during the laminated glass production process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional interlayer film is heated and pressurized in an autoclave during laminated glass production, then bonding between glass members is achieved, but positional displacement between glass members occurs

Engineering Contradiction:
Improvebonding qualityVSAvoidpositional alignment
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent modifies the physical and chemical parameters of the interlayer film by controlling the glass transition temperature (33°C or less) and plasticizer content (35 parts by weight or more per 100 parts of thermoplastic resin). These parameter changes enable the film to maintain optimal bonding properties while preventing positional displacement during autoclave processing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The interlayer film is formulated as a composite material containing thermoplastic resin and plasticizer in specific proportions. This composite structure provides both the bonding capability needed for reliable lamination and the dimensional stability required to prevent glass member displacement during heating and pressurization.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If interlayer film has high plasticizer content to prevent displacement, then positional stability improves, but film flexibility may be affected

Engineering Contradiction:
Improvepositional stabilityVSAvoidfilm flexibility
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent optimizes the plasticizer content parameter to 35 parts by weight or more per 100 parts of thermoplastic resin, which provides sufficient positional stability while maintaining appropriate film flexibility for the lamination process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The interlayer film exhibits different physical properties at different stages of processing: during autoclave treatment, the high plasticizer content provides positional stability, while during handling and installation, the thermoplastic resin maintains sufficient flexibility.

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 effectively prevents positional displacement between glass members, ensuring accurate alignment and enhancing the handling properties of laminated glass, thereby improving the manufacturing process and product quality.

Implementation Method 1

ΔnMDA, ΔnMDB, and ΔnMDC each are 0.50 × 10-3

Methodology Applied
Scientific EffectBirefringence: Birefringence

Implementation Method 2

a glass transition temperature of 33°C or less

Methodology Applied
Scientific EffectGlass transition:

Data Source

PatentEP3279165B1Interlayer for laminated glass and laminated glass
Publication Date: 2023.09.06 SEKISUI CHEMICAL CO LTD
  • EP3279165B1 patent drawingFigure 1~3
  • EP3279165B1 patent drawingFigure 4~5(c)
  • EP3279165B1 patent drawing

AI summary

There is provided an interlayer film for laminated glass with which positional displacement between two lamination glass members can be prevented. The interlayer film for laminated glass according to the present invention is arranged between a first lamination glass member and a second lamination glass member to obtain laminated glass, the interlayer film contains a thermoplastic resin and a plasticizer, when, in the MD direction of the interlayer film, a birefringence index of the first surface part, a birefringence index of the second surface part, and a birefringence index of the center part are defined as ΔnMDA, ΔnMDB, and ΔnMDC, respectively, ΔnMDA, ΔnMDB, and ΔnMDC each are 0.50 × 10-3 or less, and the glass transition temperature of the interlayer film is 33°C or less or the content of the plasticizer in the interlayer film is 35 parts by weight or more relative to 100 parts by weight of the thermoplastic resin in the interlayer film.