Multilayer Interlayer Film for Laminated Glass
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Solution Overview
Problem
Laminated glass formed with existing interlayer films exhibits insufficient sound insulation, particularly at frequencies around 2000 Hz, and may experience bubble formation due to increased plasticizer amounts, which can compromise sound insulation and structural integrity.
Innovation Solution
A multilayer interlayer film with specific layer configurations, where the first layer contains a polyvinyl acetal resin with a higher plasticizer content and lower hydroxyl content compared to the second and third layers, controlling the hydroxyl content difference and degree of acetylation to inhibit plasticizer migration and bubble formation, while enhancing sound insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of plasticizer is increased to improve sound insulation, then sound insulation performance is improved, but bubble formation occurs in the laminated glass
Solution Approach 1:
The interlayer film is divided into multiple layers with different plasticizer contents. The first layer contains a higher amount of plasticizer (50-80 parts by weight per 100 parts of polyvinyl acetal resin) to provide sound insulation, while the second layer contains a lower amount (10-40 parts by weight per 100 parts of polyvinyl acetal resin) to prevent bubble formation. This segmentation allows each layer to perform its specific function without the adverse effects affecting the overall system.
Solution Approach 2:
Different regions (layers) of the interlayer film are assigned different plasticizer concentrations tailored to their specific functions. The first layer positioned away from the glass plates has high plasticizer content for sound insulation, while the second layer adjacent to the glass plates has low plasticizer content to prevent bubble formation at the critical glass-film interface.
2Reliability
If a multilayer interlayer film with sound insulation layer is used to improve sound insulation at around 20°C, then sound insulation is increased, but bubble formation may occur in the laminated glass
Solution Approach 1:
The interlayer film is divided into multiple layers with different plasticizer contents. The first layer contains a higher amount of plasticizer (50-80 parts by weight per 100 parts of polyvinyl acetal resin) to provide sound insulation, while the second layer contains a lower amount (10-40 parts by weight per 100 parts of polyvinyl acetal resin) to prevent bubble formation. This segmentation allows each layer to perform its specific function without the adverse effects affecting the overall system.
3Reliability
If the hydroxyl content of polyvinyl acetal resin is reduced to increase plasticizer amount for sound insulation, then sound insulation is improved, but bubble formation risk increases
Solution Approach 1:
The interlayer film is divided into multiple layers with different plasticizer contents. The first layer contains a higher amount of plasticizer (50-80 parts by weight per 100 parts of polyvinyl acetal resin) to provide sound insulation, while the second layer contains a lower amount (10-40 parts by weight per 100 parts of polyvinyl acetal resin) to prevent bubble formation. This segmentation allows each layer to perform its specific function without the adverse effects affecting the overall system.
Solution Approach 2:
The hydroxyl content of the polyvinyl acetal resin is precisely controlled within specific ranges (23-32 mol% for the first layer, 26-35 mol% for the second layer) to optimize the balance between plasticizer compatibility and bubble formation prevention, allowing high plasticizer content without excessive bubble formation.
Data Source
Figure 1~2
AI summary
The present invention provides an interlayer film for a laminated glass, comprising a first layer that contains a polyvinyl acetal resin and a plasticizer, and a second layer that contains a polyvinyl acetal resin and a plasticizer and is laminated on one face of the first layer, wherein an amount of the plasticizer for each 100 parts by weight of the polyvinyl acetal resin in the first layer is 50 parts by weight or higher, the hydroxyl content of the polyvinyl acetal resin in the first layer is lower than the hydroxyl content of the polyvinyl acetal resin in the second layer, the difference between the hydroxyl content of the polyvinyl acetal resin in the first layer and the hydroxyl content of the polyvinyl acetal resin in the second layer is at most 9.2 mol%, and the polyvinyl acetal resin in the first layer has a degree of acetylation of at most 8 mol% in the case that the difference between the hydroxyl content of the polyvinyl acetal resin in the first layer and the hydroxyl content of the polyvinyl acetal resin in the second layer is more than 8.5 mol% and at most 9.2 mol%, and the interlayer film for a laminated glass satisfied as below: the amount of the plasticizer for each 100 parts by weight of the polyvinyl acetal resin in the first layer is larger than the amount of the plasticizer for each 100 parts by weight of the polyvinyl acetal resin in the second layer by 25 parts by weight or more, the hydroxyl content of the polyvinyl acetal resin in the first layer is 27 mol% or less, and the hydroxyl content of the polyvinyl acetal resin in the second layer is 27 mol% or more.