Laminated Glass Interlayer Film Gap Prevention

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional interlayer films for laminated glass often result in gaps at the ends of the glass sheets when exposed to light or heat, leading to reduced adhesive force and increased yellow index values, which affect the appearance and performance of the laminated glass.

Innovation Solution

A multi-layer interlayer film structure incorporating a polyvinyl acetal resin, plasticizer, hindered amine light stabilizer, and oxidation inhibitor containing phosphorus, with specific layer configurations to enhance adhesion, prevent gap formation, and maintain optical quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional interlayer film is used, then the basic lamination function is achieved, but gaps are generated at the end part when exposed to light and heat

Engineering Contradiction:
Improvegap resistanceVSAvoidinterlayer film integrity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameters of the interlayer film by incorporating specific additives (hindered amine light stabilizer at 0.01-0.5 wt%, oxidation inhibitor containing phosphorus at 0.01-2.0 wt%) into the polyvinyl acetal resin matrix. These parameter changes enhance the film's resistance to gap formation under light and heat exposure while maintaining overall compositional stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite interlayer film material by combining polyvinyl acetal resin with hindered amine light stabilizers and oxidation inhibitors containing phosphorus. This composite structure provides both the basic lamination function and enhanced resistance to gap formation, resolving the contradiction between reliability and compositional stability.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a conventional interlayer film is used, then the lamination structure is formed, but the yellow index value increases at the end part

Engineering Contradiction:
Improveoptical quality stabilityVSAvoidyellowing
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts harmful factors (light and heat that cause yellowing) into beneficial effects by using hindered amine light stabilizers and oxidation inhibitors. These additives absorb UV radiation and prevent oxidative degradation, transforming the previously harmful light and heat exposure into conditions that maintain optical quality without yellowing.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The hindered amine light stabilizer and oxidation inhibitor act as intermediary substances between the polyvinyl acetal resin and the harmful light/heat environment. They mediate the interaction by absorbing UV energy and preventing direct damage to the resin, thereby suppressing yellowing while maintaining optical quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If a conventional interlayer film is used, then the basic adhesive function is provided, but adhesive force is lowered due to gap formation

Engineering Contradiction:
Improveadhesive forceVSAvoidend part uniformity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies preliminary protective action by incorporating hindered amine light stabilizers and oxidation inhibitors into the interlayer film before lamination. This preliminary stabilization prevents gap formation at the end parts, thereby maintaining uniform adhesive force across the entire lamination structure without requiring post-processing corrections.

Inventive Principle:
Principle #10Preliminary action

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 effectively prevents gap formation and suppresses the increase in yellow index values at the ends of laminated glass sheets, ensuring improved adhesive force and optical stability even under prolonged exposure to light and heat.

Implementation Method 1

having high transmittance for UV-A rays and visible light, and having low transmittance for UV-B rays

Methodology Applied
Scientific EffectUV absorption: Absorption (EM radiation)

Implementation Method 2

at least one layer among the first layer, the second layer, and the third layer includes a hindered amine light stabilizer

Methodology Applied
Scientific EffectPhoto-oxidation prevention: Photo-oxidation

Implementation Method 3

at least one layer among the first layer, the second layer, and the third layer includes an oxidation inhibitor containing phosphorus

Methodology Applied
Scientific EffectOxidation inhibition: Oxidation

Data Source

PatentEP3053889B1Intermediate film for laminated glass, and laminated glass
Publication Date: 2019.08.28 SEKISUI CHEMICAL CO LTD
  • EP3053889B1 patent drawingFigure 1~3
  • EP3053889B1 patent drawing

AI summary

There is provided an interlayer film for laminated glass in which a gap is difficult to be generated at the end part of a sheet of laminated glass and an increase in the YI value measured at the end part of the sheet of laminated glass can be suppressed. The 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, including a polyvinyl acetal resin, a plasticizer, a hindered amine light stabilizer and an oxidation inhibitor containing phosphorus in the interlayer film as a whole.