Search Results

The continual trend towards weight reduction resulted in the implementation of molded polyurethane carpet underlay at a density of 43 kg/m3 in early 2000. Now, through new formulation developments, coupled with the production introduction of carbon dioxide co-blown technology, additional weight reductions have been achieved. This has resulted in molded densities of 34 kg/m3 to be reached in prototype moldings. In addition to weight reductions, there has also been a renewed focus on improving the acoustical performance of the sound insulation material. As a result, a new family of formulations has been developed which have shown acoustical improvement while not sacrificing weight. This paper will showcase these new developments and highlight the benefits of polyurethane in sound insulation applications.

Weight reduction with maintained part performance is a continuing trend throughout the automotive industry. Acoustical insulation parts (carpet underlay and dash insulators) are no exception. Several years ago, ICI Polyurethanes led the industry in establishing a molded density standard of 48 kg/m3. Although this is the current production standard, the technology drive is toward even lower weights. Recent technological demonstrations show that molded densities of 35-38 kg/m3 are achievable. In addition to removing weight, acoustical performance can be maintained with no deficiencies in physical characteristics.

ICI has reviewed the acoustical performance of cast polyurethane foam and shoddy pad when used for Automotive Carpet Underlay applications. Data will be presented on a range of all MDI-based acoustic foam systems as well as traditional automotive carpet underlay material. Particular attention will be paid to the influence of compression set durability on acoustical performance. Using a newly developed test method to simulate long-term in-vehicle usage, it will be shown that extended compression gives an acoustic improvement when using polyurethane foam compared to conventional shoddy pad. Additionally, it has been shown that recent advances in polyurethane foam density reduction have not adversely affected acoustic performance in automotive carpet underlay applications.