Multi-Layer Interlayer Film for Laminated Glass Bubble Suppression
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Solution Overview
Problem
Laminated glass using existing interlayer films exhibits insufficient sound insulation, particularly at frequencies around 2000 Hz, and may experience bubble formation due to high plasticizer content, which affects sound transmission and structural integrity.
Innovation Solution
A multi-layer interlayer film structure with a first layer containing polyvinyl acetal resin, carboxylic acid-modified polyvinyl acetal resin, or both, along with a plasticizer, and a second layer also containing polyvinyl acetal resin and a plasticizer, where the first layer optionally includes a compound with a boron atom, to enhance sound insulation and prevent bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of plasticizer in the interlayer film 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 (contacting glass) contains 20-40 parts plasticizer per 100 parts resin to prevent bubble formation, while the second layer (intermediate layer) contains 40-80 parts plasticizer per 100 parts resin to provide sound insulation. This segmentation allows each layer to fulfill its specific function without causing harmful effects.
Solution Approach 2:
Different regions of the interlayer film are assigned different plasticizer concentrations based on their functional requirements. The first layer has lower plasticizer content optimized for adhesion and bubble prevention, while the second layer has higher plasticizer content optimized for sound insulation. This local quality differentiation resolves the contradiction between sound insulation and bubble formation.
2Reliability
If a sound insulation layer with metal salts and plasticizer is used to improve sound insulation, then sound insulation is enhanced, but bubble formation may occur in the laminated glass
Solution Approach 1:
The interlayer film is segmented into a first layer without metal salts (to prevent bubble formation) and a second layer containing metal salts and high plasticizer content (for sound insulation). This segmentation isolates the bubble-causing elements from the glass interface while maintaining sound insulation functionality.
Solution Approach 2:
The metal salt component is extracted from the first layer (glass-contacting layer) and placed only in the second layer. This extraction removes the harmful element that causes bubble formation while preserving the sound insulation function in the second layer where high plasticizer content is necessary.
3Reliability
If the plasticizer content is increased beyond 30 parts per 100 parts resin, then sound insulation improves, but the laminated glass may exhibit insufficient sound insulation at around 20°C
Solution Approach 1:
The interlayer film is segmented into layers with different plasticizer contents to address temperature-dependent sound insulation. The first layer with moderate plasticizer (20-40 parts) maintains stability at 20°C, while the second layer with high plasticizer (40-80 parts) provides enhanced sound insulation at other temperatures.
Solution Approach 2:
The plasticizer content parameter is changed across different layers of the interlayer film. By varying the plasticizer concentration from 20-40 parts in the first layer to 40-80 parts in the second layer, the invention optimizes sound insulation performance across different temperature conditions while preventing bubble formation.
Data Source
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Figure 3
AI summary
The present invention provides an interlayer film for a laminated glass which can suppress bubble formation and bubble growth in the laminated glass. An interlayer film for a laminated glass according to the present invention includes a first layer and a second layer laminated on one face of the first layer, each of the first layer and the second layer contains a polyvinyl acetal resin, contains a carboxylic acid-modified polyvinyl acetal resin, or contains both a polyvinyl acetal resin and a carboxylic acid-modified polyvinyl acetal resin, each of the first layer and the second layer contains a plasticizer, and when the first layer does not contain the carboxylic acid-modified polyvinyl acetal resin, the first layer contains a compound having a boron atom.