Colored Laminated Glass Interlayer for Uniform Low Transmittance
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Solution Overview
Problem
Existing interlayer films for colored laminated glass with high visible light transmittance of 5% or lower exhibit significant variation in transmittance from portion to portion due to recesses on the surface, leading to an improper appearance.
Innovation Solution
The interlayer film is designed as a laminate of at least two layers, with a first resin layer containing a thermoplastic resin and a colorant, and a second resin layer without a colorant, where the first resin layer has increased elastic modulus to prevent recesses from transferring to the interface, maintaining consistent visible light transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a large amount of colorant is added to achieve visible light transmittance of 5% or lower, then the privacy protection and light blocking properties are improved, but the variation in visible light transmittance from portion to portion increases, leading to improper appearance
Solution Approach 1:
The interlayer film is divided into multiple layers (first interlayer film with colorant, second interlayer film without colorant) to separate the functions of light blocking and uniformity control, preventing the variation problems associated with high colorant concentration in a single layer
Solution Approach 2:
The patent uses a composite structure combining colored and colorless interlayer films, where the colorless layer acts as a buffer to reduce transmittance variation while the colored layer provides the required light blocking, achieving both high opacity and visual uniformity
2Ease of manufacture
If recesses are formed on the surface of the interlayer film to ensure deaeration properties during production, then the ease of manufacture is improved, but the variation in visible light transmittance from portion to portion increases, leading to improper appearance
Solution Approach 1:
The interlayer film structure is segmented into colored and colorless layers, with the colorless layer positioned to mask the visual impact of surface recesses while maintaining their deaeration function
Solution Approach 2:
The colorless interlayer film acts as an intermediary layer that optically masks the surface recesses, preventing them from causing visible transmittance variation while allowing the recesses to continue serving their deaeration purpose
Data Source
Figure 1~3
AI summary
The present invention aims to provide an interlayer film for a colored laminated glass which exhibits a visible light transmittance Tv of 5% or lower, small variation in visible light transmittance and an excellent appearance when incorporated in a laminated glass together with two clear glass plates in conformity with JIS R3202 (1996), and a colored laminated glass produced using the interlayer film for a colored laminated glass. Provided is an interlayer film for a colored laminated glass having recesses on at least one surface, and exhibiting a visible light transmittance Tv of 5% or lower when incorporated in a laminated glass together with two clear glass plates in conformity with JIS R3202 (1996), the interlayer film for a colored laminated glass including a laminate of at least two layers including a first resin layer containing a thermoplastic resin and a colorant and a second resin layer containing a thermoplastic resin and no colorant, the elastic modulus E1 of the first resin layer and the elastic modulus E2 of the second resin layer having a ratio E1/E2 of 1.25 or more, the thickness t1 of the first resin layer and the thickness t2 of the second resin layer having a ratio t1/t2 of 2.0 or less.