Polymer Interlayer Sound Insulation via Tg Control
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Solution Overview
Problem
Current polymer interlayers in glass panels, particularly in vehicle and building glazings, fail to adequately address sound insulation issues, especially in the wind noise frequency region, due to the coincident effect which leads to reduced sound transmission loss at specific frequencies.
Innovation Solution
A polymer interlayer comprising a poly(vinyl acetal) resin with specific residual hydroxyl and acetate content, combined with a plasticizer, is developed to achieve improved sound insulation properties. This interlayer has a glass transition temperature less than 20°C and a peak tan delta greater than 1.29, enhancing sound transmission loss across the 2000 to 8000 Hz frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional polymer interlayers are used in glass panels, then the basic safety and bonding functions are achieved, but the sound insulation properties are insufficient especially in the wind noise frequency region due to the coincident effect
Solution Approach 1:
The patent applies parameter changes by precisely controlling the glass transition temperature (Tg) to be less than 20°C and the tan delta peak to be greater than 1.29. These parameter modifications to the polymer interlayer material enable it to effectively counteract the coincident effect in the 2000-8000 Hz frequency range, achieving sound transmission loss greater than 38 dB at coincident frequency and weighted average sound transmission loss greater than 41 dB
Solution Approach 2:
The patent employs composite materials by formulating a polymer interlayer that combines poly(vinyl acetal) resin with specific residual hydroxyl and acetate content alongside a plasticizer. This composite material structure creates synergistic effects that enhance sound insulation properties while maintaining the necessary mechanical性能和 bonding characteristics
2Object-affected harmful factors
If the glass transition temperature is reduced below 20°C and peak tan delta is increased above 1.29 to improve sound insulation, then the coincident effect is mitigated, but the manufacturing precision and material formulation complexity increase
Solution Approach 1:
The patent specifies precise parameter ranges (Tg < 20°C, tan delta peak > 1.29) that must be achieved through controlled material formulation and processing. These parameter specifications guide manufacturers in selecting appropriate resin compositions and plasticizer ratios, enabling consistent production of interlayers with optimized acoustic performance
Solution Approach 2:
The patent incorporates feedback mechanisms by establishing clear performance criteria (sound transmission loss > 38 dB at coincident frequency, weighted average > 41 dB) that can be measured and used to adjust manufacturing parameters. This feedback loop ensures that the complex material formulation process produces interlayers meeting the specified acoustic performance targets
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 significantly improves sound insulation by achieving weighted average sound transmission losses greater than 41 decibels and coincident frequency sound transmission losses greater than 38 decibels, effectively mitigating the coincident effect and reducing noise transmission.
Implementation Method 1
The sound insulation property of a glass panel can be characterized by Sound Transmission Loss (STL). It is well known that sound transmission through glass exhibits coincident effect.
Implementation Method 2
The main function of the interlayer in the laminated safety glass is to absorb energy resulting from impact or force applied to the glass
Implementation Method 3
The coincident effect not only results in a dip or decrease in sound transmission loss at the coincident frequency, but also reduces sound transmission loss at frequencies above and below the coincident frequency
Data Source
AI summary
A polymer interlayer comprising a layer comprising a poly(vinyl acetal) resin having a residual hydroxyl content and a residual acetate content, and a plasticizer, wherein the residual hydroxyl content, the residual acetate content and the plasticizer are selected such that the polymer interlayer has at least one glass transition temperature less than about 20° C. and a peak tan delta of greater than 1.29, and a glass panel having a configuration of 2.3-mm glass//interlayer//2.3-mm glass and at 20° C. has a transmission loss, TLw, of greater than 41 decibels as measured by weighted average sound transmission loss at 2000 to 8000 Hz, and a transmission loss, TLc, of greater than 38 decibels at the coincident frequency is disclosed.