Laminated Vehicle Window Glass With Moisture-Blocking Interlayer Edge
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Solution Overview
Problem
Thinner glass sheets in laminated vehicle window glasses result in reduced rigidity, leading to a high risk of elastic deformation and interfacial separation between the interlayer film and glass sheets, especially when the end face is exposed to air, which complicates the Pummel test and affects safety.
Innovation Solution
A laminated glass configuration with a high-rigidity interlayer film sandwiched between glass sheets, where at least one end face of the interlayer film is exposed to air, featuring a main rigid layer and a peripheral non-rigid layer to prevent water absorption, with the rigid layer's water content controlled to 0.5% or lower, ensuring the glass sheets are 2.0 mm or thinner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If thinner glass sheets are used to reduce weight, then the weight of the laminated glass pane is reduced, but the rigidity of the laminated glass pane decreases
Solution Approach 1:
The patent uses a composite interlayer film structure combining PVB resin and PVOH resin in specific layers. The PVOH resin layers (with water content 3-10%) provide enhanced rigidity and dimensional stability, while the PVB resin layers maintain adhesion and flexibility. This composite material approach allows the use of thinner glass sheets (reducing weight) while compensating for rigidity loss through the high-rigidity interlayer film.
Solution Approach 2:
The patent controls the water content of PVOH resin in the interlayer film at 3-10%, which optimizes the rigidity and dimensional stability of the interlayer. By adjusting this parameter, the interlayer film achieves sufficient stiffness to prevent elastic deformation of thin glass sheets while maintaining adhesion performance. The water content is controlled to balance rigidity enhancement with prevention of excessive water absorption that would cause swelling.
2Strength
If high-rigidity interlayer film is used to compensate for rigidity decrease, then the rigidity of the laminated glass pane is improved, but the water absorbency of the interlayer film increases
Solution Approach 1:
The patent employs a multi-layer interlayer film structure where different layers have different resin compositions and water content characteristics. The PVOH resin layers (with controlled 3-10% water content) provide local rigidity enhancement, while PVB resin layers provide adhesion and flexibility. This local differentiation allows the high-rigidity PVOH layers to compensate for glass sheet thinning without requiring the entire interlayer to have high water absorbency, thus balancing rigidity improvement with water absorption control.
Solution Approach 2:
The patent precisely controls the water content of PVOH resin at 3-10% to optimize the balance between rigidity and water absorption. By adjusting this parameter, the interlayer achieves sufficient stiffness to support thin glass sheets while limiting excessive water uptake that would lead to swelling and adhesion failure. This parameter optimization resolves the contradiction between needing high rigidity and minimizing water absorbency.
3Adaptability or versatility
If the end face of the interlayer film is exposed to air, then the design flexibility of the vehicle window glass is improved, but the risk of water absorption at the end side increases
Solution Approach 1:
The patent uses a multi-layer interlayer film structure with PVOH resin layers having controlled water content (3-10%) positioned to provide local rigidity and dimensional stability at the exposed end faces. This local quality enhancement at the exposed surfaces prevents water-induced swelling and adhesion failure while allowing the end faces to remain exposed for design flexibility. The differentiated layer structure protects vulnerable exposed areas without requiring full encapsulation.
4Weight of moving object
If thinner glass sheets are used, then the weight is reduced, but the risk of interfacial separation between the interlayer film and glass sheets increases
Solution Approach 1:
The patent uses a composite interlayer film combining PVB resin (providing adhesion) and PVOH resin (providing rigidity). The PVB resin layers ensure good adhesion to glass sheets, while PVOH resin layers with controlled water content (3-10%) provide dimensional stability and prevent excessive swelling. This composite structure maintains reliable adhesion even when glass sheets are thin, preventing interfacial separation while enabling weight reduction.
Solution Approach 2:
The patent controls the water content of PVOH resin at 3-10% to optimize dimensional stability and prevent excessive swelling that would cause adhesion failure. By maintaining water content within this range, the interlayer film achieves sufficient rigidity to support thin glass sheets without swelling enough to compromise the adhesion bond between the interlayer and glass, thus preventing interfacial separation while enabling use of thinner glass.
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
This configuration reduces the risk of interfacial separation between the interlayer film and glass sheets, maintaining the glass's shape under stress and improving safety by preventing water absorption into the interlayer film, thus enhancing the Pummel test performance and durability.
Implementation Method 1
the high-rigidity interlayer film, in a state of being adhered to the glass sheets, has a large tendency to show overtime such a degree of variation in water absorbency
Implementation Method 2
featuring a main rigid layer and a peripheral non-rigid layer to prevent water absorption
Data Source
AI summary
A vehicle window glass (10) includes a first glass sheet (1), a second glass sheet (2) and an interlayer film (3) sandwiched between a second surface (S2) of the first glass sheet and a third surface (S3) of the second glass sheet. For weight reduction, at least one of the glass sheets (1, 2) has a thickness of 2.0 mm or smaller. The interlayer film (3) has a main part (4) provided with a rigid layer and a peripheral part (5) formed of a non-rigid layer. The peripheral part (5) is disposed along an upper side of the vehicle window glass (10) which is exposed to air. Contact of water with the rigid layer of the main part (4) is prevented by the non-rigid layer of the peripheral part (5). The rigid layer has a water content controlled to 0.5% or lower as measured by near-infrared spectroscopy.