What are the car sound insulation materials

To understand the sound insulation of the first to understand the source of noise of the car, car noise is partly from the engine, part of the vibration from the car, and another is that the environment is more than the wind. Depending on the source of the noise and the different parts of the body, different sound insulation materials are required from a professional point of view, such as the sound insulation and insulation of the hood.
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Generally now, there are two kinds of sound insulation materials used for automobile modification, one is butyl rubber, the other is a double component (PP+PET) sound absorption cotton. Butyl rubber is the main material of the shock plate we often say, and PP+PET is the sound insulation cotton (white cotton). The sound comes from the vibration, so to reduce the noise in the box is to stop the shock first, that is to reduce the body vibration, the shock plate itself is more dense and the outer layer is covered with a layer of aluminum foil, so the shock plate can play a very good sound insulation effect. The sound is also divided into different frequencies, the two components of the sound absorption cotton are relatively fluffy and there are numerous small micropores in the middle, which mainly play a sound absorption effect. At the same time, the application of 40 grams of non-woven fabric on the outer layer of the sound-absorbing cotton can also play the effect of sound insulation, so that the noise of different frequencies is digested.
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For the best refitting effect, the car friends can choose the shock plate and the sound absorption cotton at the same time. The general modification can also only use the sound absorption cotton, and it will also play a certain effect.