Laminated Glass Interlayer Film with Controlled Color Gradient

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Solution Overview

Problem

Conventional colored interlayer films for laminated glass lack consideration for uniformity and aesthetic quality in color shade changes across the film, resulting in inadequate aesthetic appeal.

Innovation Solution

The interlayer film for laminated glass is designed with specific control of L*, a*, and b* changes, along with visible light transmittance (Tv) differences, ensuring ΔL*+Δa*+Δb* ≥ 0.5 and ΔTv ≥ 0.1%, with varying resin layer thickness to achieve desired aesthetic effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional colored interlayer films are used with colored layers, then the transmittance can be reduced to protect passengers from direct sunlight, but the aesthetic quality is insufficient due to lack of control over color shade changes

Engineering Contradiction:
Improveprotection from direct sunlightVSAvoidaesthetic quality
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by precisely controlling the color shade parameters (L*, a*, b*) and visible light transmittance (Tv) of the colored interlayer film. By establishing specific ranges for these parameters and their changes across the film surface, the invention transforms the conventional approach into a scientifically controlled process that simultaneously achieves both protection function and aesthetic quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements local quality by allowing different regions of the interlayer film to have different color shades and transmittance values. The colored layer can have varying L*, a*, b* values at different positions, enabling gradient effects and localized aesthetic variations while maintaining overall protection performance

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the color shade changes from one end to the other end of the interlayer film, then design flexibility is improved, but the control over color uniformity and aesthetic quality becomes difficult

Engineering Contradiction:
Improvedesign flexibilityVSAvoidcolor uniformity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent systematically controls parameter changes across the film by defining maximum allowable differences in L*, a*, b* values between different regions. This structured approach to parameter variation enables design flexibility while maintaining manufacturing precision through quantifiable control criteria

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent establishes feedback mechanisms by measuring and evaluating the actual L*, a*, b* values and transmittance (Tv) of the produced interlayer film against predetermined standards. This quality control feedback ensures that color uniformity and aesthetic quality requirements are met while allowing for design variations

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4596516A1Intermediate film for laminated glass, and laminated glass
Publication Date: 2025.08.06 SEKISUI CHEMICAL CO LTD
  • EP4596516A1 patent drawingFigure 1~4
  • EP4596516A1 patent drawingFigure 5~7
  • EP4596516A1 patent drawing

AI summary

An interlayer film for laminated glass comprises one or more resin layers wherein at least one of the resin layers contains a colorant, and wherein when the absolute values of the differences between the maximum and minimum values of L*, a* and b* measured from one end to the other end of a laminated glass including two sheets of clear glass with a thickness of 2.5 mm bonded through the interlayer film for laminated glass are represented by ΔL*, Δa* and Δb*, respectively, the value of ΔL*+Δa*+Δb* is 0.5% or more.