Laminated Glass Interlayer Film Discoloration Control
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Solution Overview
Problem
Conventional laminated glass experiences discoloration, particularly yellowing, at the end parts due to exposure to light and heat, which affects the appearance and transparency, and increasing ultraviolet absorber content reduces transparency.
Innovation Solution
The laminated glass incorporates a thermoplastic resin interlayer film with a polyvinyl acetal resin, specifically polyvinyl butyral, where the hydroxyl group content ratio between the end and inner parts is controlled to prevent discoloration, maintaining transparency and appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the adding amount of ultraviolet absorber is increased to prevent discoloration, then discoloration resistance is improved, but transparency is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the interlayer film by specifying a polyvinyl acetal resin with controlled hydroxyl group content (15-35 mass%) and particular structural characteristics. This compositional parameter change enables the material to resist discoloration through its molecular structure rather than relying on high concentrations of ultraviolet absorbers, thereby maintaining transparency while achieving discoloration resistance.
Solution Approach 2:
The patent creates a composite material system combining polyvinyl acetal resin with specific additives including ultraviolet absorbers (0.01-5 mass%), oxidation inhibitors (0.01-5 mass%), and plasticizers (1-50 mass%). This composite formulation achieves synergistic effects where the base resin provides inherent stability and the additives enhance specific properties, allowing optimal balance between discoloration resistance and transparency that neither component could achieve alone.
2Adaptability or versatility
If the interlayer film is multi-layered to improve functionality, then performance is enhanced, but discoloration likelihood increases due to layer contact with glass plate
Solution Approach 1:
The patent applies local quality by creating a multi-layer structure where at least the layer in contact with the glass plate is composed of polyvinyl acetal resin with specific hydroxyl group content (15-35 mass%). This localized composition ensures that the critical interface region has enhanced discoloration resistance properties, while other layers can be optimized for different functions such as adhesion, flexibility, or optical properties.
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 discoloration in the interlayer film of laminated glass, ensuring excellent appearance and transparency by controlling the hydroxyl group content ratio and using a polyvinyl butyral resin, even after light irradiation testing.
Implementation Method 1
The ultraviolet absorber used in the interlayer film is a malonic ester compound and/or an oxanilide compound
Data Source
AI summary
Provided is laminated glass capable of preventing occurrence of discoloration in the interlayer film in an end part of laminated glass, and keeping the appearance of laminated glass excellent. Laminated glass according to the present invention is laminate glass including a first lamination glass member, a second lamination glass member, and an interlayer film containing a thermoplastic resin, in which no discoloration occurs in the interlayer film irradiated with light in an end part of the laminated glass after a light irradiation test: “the laminated glass is irradiated with xenon light at a black panel temperature of 83° C., a temperature inside the vessel of 50° C. and a humidity of 50% RH for 2000 hours”, or discoloration occurs within a length of 1 mm or less inwardly from an end part of the interlayer film irradiated with light in the end part of the laminated glass after the light irradiation test.