ABSTRACT
Control technology of some comfort properties of polyurethane seat cushion has been getting important.
control of ball rebound resiliency suited to each car concept
control of transmission of the vibration from an automotive body to a passenger
good durability for keeping riding comfort for a long time
We consider that it is important to control ball rebound resiliency and transmission of the vibration individually. In this study, we compared some properties of foams with wide range of polymer and cell structure in order to discuss the effect of these structures on characteristics mentioned above. Ball rebound resiliency is influenced by both polymer and cell structure, but polymer stmcture is the more influenced factor. Transmissibility of lower frequency, 2–4 Hz, is affected by the cell structure strongly. The coefficient of viscosity of polyurethane foam can be adjusted by control of the viscous resistance of air flowability through cells appropriately. This resistance is defined with the cell window size. On the other hand, transmissibility of higher frequency, such as 6 Hz, is influenced by polymer structure. Both polymer and cell structure affect durability, but it was found that the contribution of polymer structure is bigger.
These polymer and cell structure can be controlled by the selection of raw materials and formulation. Low air flowability generally causes tight cell at demolding, but regulating cell open mechanism using appropriate raw material can avoid the problem.
