Laminated Glass Interlayer Film Rigidity and Sound Insulation
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Solution Overview
Problem
Conventional interlayer films for laminated glass often result in low flexural rigidity, making it difficult to maintain rigidity, especially when thin glass plates are used, and struggle to maintain sound insulating properties over time.
Innovation Solution
A three or more-layer interlayer film with specific layer compositions and hydroxyl group content differences, including a first layer with lower hydroxyl group content compared to the second and third layers, and controlled plasticizer distribution to prevent excessive transfer and maintain rigidity and sound insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional interlayer film is used, then the laminated glass can be manufactured, but the flexural rigidity is low making it difficult to maintain rigidity especially when thin glass plates are used
Solution Approach 1:
The interlayer film is divided into multiple layers with different compositions. The first layer contains polyvinyl acetal resin with 60-85% acetalization degree and specific plasticizer content for initial rigidity, while the second layer contains polyvinyl acetal resin with 85-95% acetalization degree for long-term rigidity maintenance. This segmentation allows each layer to perform its specific function optimally.
Solution Approach 2:
The invention uses a composite interlayer film structure combining different polyvinyl acetal resin compositions with varying acetalization degrees and plasticizer contents. This composite approach enables the film to provide both immediate flexural rigidity and long-term rigidity maintenance, solving the contradiction between using thin glass plates (weight reduction) and maintaining sufficient rigidity.
2Object-affected harmful factors
If an interlayer film with high sound insulating properties is used, then sound insulation is improved, but the flexural rigidity becomes difficult to maintain
Solution Approach 1:
The interlayer film is segmented into functional layers: the first layer with polyvinyl acetal resin (60-85% acetalization) and plasticizer provides sound insulating properties, while the second layer with polyvinyl acetal resin (85-95% acetalization) and lower plasticizer content maintains flexural rigidity. This segmentation resolves the contradiction by assigning different functions to different layers.
3Weight of moving object
If the thickness of glass plate is thinned to reduce weight, then the weight of laminated glass is reduced, but maintaining sufficient flexural rigidity becomes difficult
Solution Approach 1:
The invention changes the chemical composition parameters of the interlayer film, specifically using polyvinyl acetal resin with different acetalization degrees (60-85% in first layer, 85-95% in second layer) and controlling plasticizer content (3-50 parts by weight in first layer, 0-3 parts by weight in second layer). These parameter changes enable the interlayer film to compensate for the reduced rigidity from thinner glass plates, maintaining sufficient overall flexural rigidity while achieving weight reduction.
4Strength
If a multi-layer interlayer film structure is implemented, then rigidity can be improved, but the device complexity increases
Solution Approach 1:
The interlayer film is segmented into two layers with distinct compositions. The first layer uses polyvinyl acetal resin with 60-85% acetalization degree and 3-50 parts plasticizer, while the second layer uses polyvinyl acetal resin with 85-95% acetalization degree and 0-3 parts plasticizer. This segmentation achieves rigidity improvement while keeping the structure relatively simple compared to multi-component systems.
Data Source
AI summary
There is provided an interlayer film for laminated glass with which the flexural rigidity of laminated glass can be enhanced and the sound insulating properties of laminated glass can be enhanced. The interlayer film for laminated glass according to the present invention includes first, second, and third layers containing a polyvinyl acetal resin and a plasticizer, the content of the hydroxyl group of the polyvinyl acetal resin in the first layer is lower than the content of the hydroxyl group of the polyvinyl acetal resin in each of the second and third layers, when absolute values of a difference between the content of the hydroxyl group of the polyvinyl acetal resin in the second and third layers and the content of the hydroxyl group of the polyvinyl acetal resin in the first layer are defined as XA and XB, respectively, each of the absolute values XA and XB is 9% by mole or more and 11% by mole or less, and when a content of the plasticizer in the interlayer film relative to 100 parts by weight of the polyvinyl acetal resin in the interlayer film is defined as Y, XA, XB, and Y satisfy the equations of Y≤−1.68XA+56 and Y≤−1.68XB+56.