| abstract |
A constrained layer damping structure is provided, including a panel to be damped, a constraining layer and a layer of foam vibration damping material sandwiched therebetween. In one embodiment, the foam vibration damping material is provided from a composition including 5-50 weight percent polyvinyl butyral, 2-20 weight percent plasticizer, 25-65 weight percent filler, 1-15 weight percent tackifier, and 0.1-8 weight percent blowing agent, wherein the composition includes 15-65 weight percent total thermoplastic inclusive of polyvinyl butyral. In a further embodiment, the polyvinyl butyral is provided as recycled material from recycled auto glass, and includes a small quantity of plasticizer, typically but not necessarily of the phthalate-type or hexanoate-type. |