Future Possibility of High Performance PVB Interlayer

Multi-layer Technology for Noise Reduction and More
Terry Yoshioka
Technology & Development Center, S-LEC™ Division

  Contents    
  1. Introduction 5. Multi-layer Solution
  2. Multi-layer Technology -a. Performance - Engine Noise
  3. Sound Reduction -b. Performance - Wind Noise
  4. Limit of Mono-layer -c. Summary
      -d. Application
      6. Additional Feature
      7. Conclusion

1. Introduction

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  • Use of laminated glass in vehicle is increasing
    Windshield -- Standard in many countries
    Sidelite and other area -- EPG
  • Various functions are demanded for vehicle glazing
    PVB -- Important role to add functionality
  • Multi-layer technology makes it possible
    High performance PVB by “Function-by-Layer” concept

2. Multi-layer Technology

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  • Shade band of Windshield

Shade band of Windshield
  • S-LEC™ Sound Acoustic Film

Acoustic Film
  • S-LEC™ Sound Acoustic Film

SAF
3. Sound Reduction Go Top
 
  • Comfort (Noise Reduction)
How glass should work
  Comfort How glass should work
 
  • Transmission Loss
  Transmission Loss
  • Stated range of human hearing:
    20 - 20,000 Hz
  • Sensitive range:
    1,000 - 4,000 Hz
 
To decrease noise level, higher TL is needed especially in the sensitive range.
 
  • How to increase TL
  How to increase TL
  • Transmission Loss achieved by:
    Mass
    Stiffness
    Damping
 
  • To increase damping level, viscoelastic PVB interlayer is used (laminated glass).
  • Changes vibration energy into heat energy
  • Damping level still not enough
 
 
  • Design of new acoustic PVB
 

  • Need to attain high sound attenuation level at ordinary glass temperature (10 - 25 deg. C)
  • Lower elasticity of PVB at ambient temperature


Designed new acoustic PVB

Prototype interlayer evaluated internally

4. Limit of Mono-layer

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  • Prototype evaluation
 

Advantage

Disadvantage
  • Better sound attenuation than normal PVB
  • Low mechanical strength due to softness: low M.B.H.
  • Difficult handling due to surface stickiness
  • Possible process parameter change during prepress


  • Need to sacrifice noise reduction performance to minimize these disadvantages

5. Multi-layer Solution

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Multi-layer Technology
 
  • "Function-by-Layer” concept
  • Able to design the maximum performance by giving each function on separate layers
 

-

Core layer

Skin layer
Function
  • Sound attenuation
  • Mechanical Strength
  • Handling/processing like normal PVB film


Maximize both layers' performance independently
 
Performance Review
 
  • Noise
 
- Source Frequency Evaluation
Structure-borne Engine Low
100 - 500 Hz
Loss Factor
Air-borne Wind
Road
High
1000 - 4000 Hz
STL
  Loss Factor Sound Transmission Loss
 
  • Engine Noise - 1 : Frequency and Loss Factor
  Frequency and Loss Factor
 
  • Multi-layer has superior performance at any frequency range.
  • Remarkable superiority at low temperature range
 
  • Wind Noise : Frequency and STL (Sound Transmission Loss)
 
Wind Noise
  • Superior wind/road noise reduction (1000 - 4000 Hz)
  • Most sensitive frequency range to human ears.
  • Summary
 
  • "Function-by-Layer” technology
    * Maximum noise reduction
    * High mechanical strength (like normal PVB interlayer)
  • BenefitS
    * Quieter vehicle cabin
    * Weight reduction / Improved fuel economy
    -Thinner glass does not increase transmission of wind noise.
  • Application
 
Automotive Architectural
Automotive Architectural
 
Figure 5 Sound transmission loss of different laminated glasses
As discussed above, multi-layer extrusion technology made it possible to choose proper viscoelastic interlayer film and maximize sound-attenuating performance of the automotive glazing system, while retaining safety and security performance. This special acoustic PVB interlayer, S-LEC™ Acoustic Film, has been adopted by several automobile manufacturers not only for high-end luxury vehicles but also for mid-class passenger cars. It achieves a quieter interior. Because of these acoustic properties, the manufactures can reduce the weight of the vehicle by using thinner (normally acoustically inferior) glass, which in turn results in better fuel efficiency.

6. Additional Feature

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  • Combined Functions
 
  • Future of high performance interlayer film
  • Sound control, Solar control, Security…
  Glass
High Performance Interlayer Film
(as one sheet)
 
  • Example - Sound & Solar Control Film
 
  • S-LEC™ Sound Acoustic Film and Solar Control Film can be combined in one PVB interlayer sheeting
  • Solar control function:
    * High visible light transmission, Low solar transmission
    * Reduced thermal skin sensation
    * EM transparency
  • Maximum passenger comfort level achieved

7. Conclusion

 
 
  • Multi-layer technology opens future possibility of high performance interlayer film
  • Example - S-LEC™ Acoustic Film
    Best performance possible through “Function-by-layer”
  • More functions added for future vehicles
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