Laminated Glass Interlayer Film Transparency and Viscosity Control
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Solution Overview
Problem
The reuse of interlayer films for laminated glass can lead to reduced transparency due to the presence of thermoplastic resins like polyvinyl acetal resin, and combining different thermoplastic resins exacerbates this issue, necessitating a solution to enhance transparency while addressing environmental concerns.
Innovation Solution
An interlayer film is developed by mixing a first composition containing a polyvinyl acetal resin with a higher hydroxyl group content and a second composition with a lower hydroxyl group content, along with a plasticizer, where the complex viscosity ratio of the second composition to the first composition is controlled to less than 4.5, ensuring improved transparency and penetration resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an interlayer film is reused as part of the raw material of a new interlayer film, then environmental load is reduced, but transparency is lowered due to the existence state of thermoplastic resin
Solution Approach 1:
The invention changes the chemical composition parameters of the thermoplastic resin by controlling the hydroxyl group content ratio between different resin components. By maintaining a specific ratio (≥4% by mole) between the first thermoplastic resin (higher hydroxyl content) and second thermoplastic resin (lower hydroxyl content), the invention optimizes the molecular structure to improve transparency while still enabling film reuse for environmental sustainability.
2Productivity
If different kinds of thermoplastic resins are combinedly used, then productivity is improved through reuse, but transparency is further reduced
Solution Approach 1:
The invention creates a composite material system by combining two different thermoplastic resins (first and second polyvinyl acetal resins) with distinct hydroxyl group content ratios. This composite approach allows the invention to leverage the advantages of material reuse for productivity while the specific compositional ratio control ensures that transparency is maintained despite the presence of multiple resin types.
3Ease of manufacture
If the content of polyvinyl acetal resin with low hydroxyl group ratio is increased, then ease of manufacture is improved, but transparency is reduced
Solution Approach 1:
The invention establishes a precise parameter control mechanism by limiting the content of polyvinyl acetal resin with low hydroxyl group ratio (less than 25% by mole) to ≤4.5% by weight. This parameter constraint ensures that while easier-to-manufacture resins can be used, their negative impact on transparency is minimized through the presence of the first thermoplastic resin with higher hydroxyl content, thereby balancing manufacturing ease with optical performance.
Data Source
Figure 1~3
AI summary
There is provided an interlayer film for laminated glass with which excessive adhesion against an interlayer film or the like can be suppressed and the transparency can be enhanced. The interlayer film for laminated glass according to the present invention is obtained by mixing a first composition containing a first thermoplastic resin having a hydroxyl group and a plasticizer and a second composition containing a second thermoplastic resin having a hydroxyl group and a plasticizer, satisfies the content ratio of the hydroxyl group of the first thermoplastic resin to be higher than the content ratio of the hydroxyl group of the second thermoplastic resin, and satisfies the ratio of the complex viscosity at 200°C of the second composition to the complex viscosity at 200°C of the first composition to be less than 4.5.