Laminated Glass Interlayer Film for Weight Reduction and Sound Insulation
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Solution Overview
Problem
Current interlayer films for laminated glass do not provide satisfactory sound insulation, which is necessary for improved comfort and fuel efficiency in vehicles, particularly due to weight reduction efforts.
Innovation Solution
An interlayer film comprising specific layers of thermoplastic resins, including a hydrogenated block copolymer layer with a peak tan δ within a certain temperature range, an inorganic glass layer with a third thermoplastic resin, and a polyvinyl acetal or ionomer resin layer, optimized for sound insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the thickness of the laminated glass is reduced to reduce weight, then the weight decreases, but the sound insulation decreases
Solution Approach 1:
The patent employs a multi-layer composite interlayer film structure combining different thermoplastic resins (SBS block copolymer, polyvinyl acetal, ionomer resin) with distinct damping characteristics. This composite structure achieves superior sound insulation by leveraging the synergistic effects of each material's viscoelastic properties, particularly through optimizing the tan δ values at different temperatures to counteract the sound insulation loss from reduced glass thickness.
Solution Approach 2:
The patent systematically optimizes critical parameters including the tan δ values of each layer at specific temperature ranges (−30°C to 10°C), layer thickness ratios, and resin composition ratios. By precisely controlling these parameters, particularly ensuring the first layer has tan δ ≥ 1.5 at −30°C and the third layer has tan δ ≥ 1.0 at 10°C, the interlayer film maintains high sound insulation performance even when the overall laminated glass thickness is reduced for weight savings.
2Weight of moving object
If conventional interlayer films are used to maintain weight, then weight reduction goals are met, but sound insulation properties remain unsatisfactory
Solution Approach 1:
The interlayer film is divided into multiple functional layers, each with specific damping characteristics optimized for different temperature conditions. The first layer (SBS block copolymer) provides high damping at low temperatures (tan δ ≥ 1.5 at −30°C), the second layer (polyvinyl acetal) provides intermediate damping, and the third layer (ionomer resin) provides high damping at elevated temperatures (tan δ ≥ 1.0 at 10°C). This segmentation allows the film to maintain effective sound insulation across the full operating temperature range while keeping the overall structure thin for weight reduction.
Solution Approach 2:
Each layer of the interlayer film is designed with specific local properties tailored to its functional requirements. The SBS block copolymer layer is optimized for low-temperature damping with specific molecular weight and soft segment content, the polyvinyl acetal layer is optimized for adhesion and intermediate damping, and the ionomer resin layer is optimized for high-temperature damping. This local optimization of material properties ensures that each portion of the composite film contributes maximally to sound insulation at its intended operating conditions.
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
The interlayer film achieves enhanced sound insulation by converting vibration energy into heat, reducing resonance effects, and maintaining mechanical strength, thereby improving the acoustic performance of laminated glass while supporting weight reduction.
Implementation Method 1
The interlayer film is capable of converting vibration energy into heat energy and absorbing the vibration energy
Implementation Method 2
a resin material constituting each A layer has a peak at which a tan δ measured by performing a complex shear viscosity test under a condition of a frequency of 1 Hz according to JIS K 7244-10: 2005 is maximum
Data Source
AI summary
An interlayer film for a laminated glass, containing in sequence an A layer, a C layer, and an A layer, and also containing a B layer at any place between or outside these layers, wherein each A layer contains a first thermoplastic resin, a resin material constituting each A layer has a tan δ peak of −30° C. to 10° C., the resin material of at least one layer of the A layers has a peak height of a tan δ of 1.5 or more, the B layer contains a second thermoplastic resin, and is constituted of a resin material different from the resin material constituting the A layer, and the C layer is a layer composed of an inorganic glass having a thickness of 0.1 mm to 1.5 mm, or a layer having a thickness of 0.25 mm to 2.5 mm and containing a third thermoplastic resin.