Laminated Glass Interlayer with Recessed Surface for Adhesion
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Solution Overview
Problem
In the production of laminated glass, thick interlayer films with a thickness of 850 µm or more often experience sealing failures at peripheral portions due to insufficient adhesion, leading to reduced transparency and poor production efficiency.
Innovation Solution
An interlayer film with a large number of recesses on at least one surface, where the thickness T and maximum height roughness Ry satisfy specific expressions (Ry ≤ 0.0195 × T + 33.2 and T ≥ 850), ensuring sufficient adhesion to glass and preventing sealing failures, while enhancing deaeration properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the interlayer film thickness is increased to 850 μm or more, then the adhesion at peripheral portions is improved, but the deaeration properties deteriorate leading to sealing failure
Solution Approach 1:
The interlayer film is designed with different surface roughness characteristics at different locations: the peripheral portions have a rougher surface (Ry ≥ 20 μm) to enhance adhesion and prevent sealing failure, while the central portion maintains a smoother surface for optimal deaeration properties. This local differentiation resolves the contradiction by allowing each region to perform its specific function effectively.
Solution Approach 2:
The invention changes the surface roughness parameter (Ry) of the interlayer film to resolve the contradiction. By controlling the surface roughness to be Ry ≥ 20 μm at peripheral portions and maintaining appropriate roughness at the central portion, the film achieves both strong adhesion at edges and good deaeration properties, enabling thick films (850 μm or more) to perform reliably.
2Strength
If the surface roughness is increased to prevent sealing failure, then the adhesion at peripheral portions is improved, but the production efficiency deteriorates due to prolonged adhesion time
Solution Approach 1:
The interlayer film is designed with different surface roughness characteristics at different locations: the peripheral portions have a rougher surface (Ry ≥ 20 μm) to enhance adhesion and prevent sealing failure, while the central portion maintains a smoother surface for optimal deaeration properties. This local differentiation resolves the contradiction by allowing each region to perform its specific function effectively.
Solution Approach 2:
The invention applies excessive surface roughness (Ry ≥ 20 μm) only where necessary - at the peripheral portions of the interlayer film - rather than making the entire surface rough. This partial application of the roughness characteristic achieves the adhesion improvement needed for sealing failure prevention while minimizing the negative impact on production efficiency.
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 sealing failures at peripheral portions, improving production efficiency and maintaining transparency by ensuring immediate adhesion after sufficient deaeration, even with thick films.
Implementation Method 1
a laminate including at least two glass plates and an interlayer film for a laminated glass interposed between the two glass plates is passed through nip rolls for deaeration (squeeze deaeration) or put in a rubber bag and vacuum suctioned (vacuum deaeration) to be preliminarily pressure-bonded while the air remaining between the glass plates and the interlayer film is removed
Implementation Method 2
the interlayer film for a laminated glass adheres sufficiently to glass at peripheral portions of the glass to prevent occurrence of a sealing failure
Data Source
Figure 1~2
Figure 3(a)~3(c)
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AI summary
The present invention aims to provide an interlayer film for a laminated glass that adheres sufficiently to glass at peripheral portions of the glass to prevent occurrence of a sealing failure at the peripheral portions and also to contribute to improved production efficiency of laminated glass in production of laminated glass, even when having a thickness at the thickest portion of 850 pm or more, and a laminated glass produced using the interlayer film for a laminated glass. Provided is an interlayer film for a laminated glass having a large number of recesses on at least one surface, the interlayer film for a laminated glass having a thickness T (µm) measured in conformity with JIS K-6732 (1996) and a maximum height roughness Ry (µm) measured in conformity with JIS B-0601 (1994) at a thickest portion, the thickness T and the maximum height roughness Ry satisfying the following expressions (1) and (1'): Ry≤0.0195×T+33.2 T≥850