Interlayer Film Viscoelastic Damping for Windshield Sound Insulation
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Solution Overview
Problem
There is a challenge in achieving a balance between reducing the weight of automobile windshields and maintaining sound insulation performance, as weight reduction leads to decreased sound transmission loss, particularly in mass-dominated and coincidence regions.
Innovation Solution
An interlayer film for laminated glass is developed, comprising a sound insulating layer formed from a composition containing a thermoplastic resin with specific dynamic viscoelastic properties and a compound with ring structures, which enhances sound insulation performance in both mass-dominated and coincidence regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the surface density of laminated glass is decreased to reduce weight, then the weight is reduced, but the sound transmission loss is decreased
Solution Approach 1:
The invention changes the physical parameters of the interlayer film by controlling the glass transition temperature range (−50 to 50°C) and specifying the tan δ minimum value (2.5 or more) at the maximum point. These parameter changes enable the film to provide effective sound insulation even when the overall glass density is reduced, thus resolving the contradiction between weight reduction and sound transmission loss maintenance.
Solution Approach 2:
The invention uses a composite interlayer film made from specific resin compositions with controlled viscoelastic properties. By combining resins with specific glass transition temperatures and damping characteristics, the film achieves both light weight and high sound insulation performance, addressing the trade-off between weight and sound transmission loss.
2Weight of moving object
If conventional interlayer films are used to reduce weight, then weight reduction is achieved, but sound insulation performance in mass-dominated and coincidence regions deteriorates
Solution Approach 1:
The invention specifically targets and changes the viscoelastic parameters of the interlayer film by defining the glass transition temperature range and tan δ characteristics. These parameter changes ensure that the film maintains high damping capacity in the critical frequency regions (mass-dominated and coincidence regions), thereby preserving sound insulation reliability while enabling weight reduction.
Solution Approach 2:
The invention creates an optimized version of conventional interlayer films by copying the basic structure but improving the material composition and viscoelastic properties. The specific resin formulation with controlled glass transition temperature and tan δ values replicates and enhances the sound insulation function while reducing weight, thus maintaining reliability in critical performance areas.
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 effectively improves sound insulation performance while allowing for weight reduction, maintaining sound transmission loss without degrading mechanical strength or transparency.
Implementation Method 1
a tan δ obtained when a dynamic viscoelasticity of a sheet, which is obtained by molding the composition (A) to have a thickness of 0.8 mm, is measured at a frequency of 0.3 Hz in a tension mode has a maximal value at a temperature TA (° C.)
Implementation Method 2
the tan δ at TA (° C.) is 2.5 or more
Data Source
AI summary
Provided is an interlayer film for laminated glass which is excellent in sound insulation property and has improved sound insulation performance not only in a coincidence region but also in a mass-dominated region. The interlayer film for laminated glass includes a sound insulating layer which is formed from a composition (A) containing at least one resin (a1) selected from a thermoplastic resin and a thermosetting resin, wherein a tan δ obtained when a dynamic viscoelasticity of a sheet, which is obtained by molding the composition (A) to have a thickness of 0.8 mm, is measured at a frequency of 0.3 Hz in a tension mode has a maximal value at a temperature TA (° C.), TA (° C.) is in a range of −50 to 50° C., and the tan δ at TA (° C.) is 2.5 or more.