Vehicle floor sheet uses polymer materials containing halogen compounds to improve flame resistance; however, the halogen compounds generate hazardous gases during combustion. Accordingly, safety in the event of a fire and in case of disposal are problematic, and there have been requirements for non-halogenized floor materials for vehicles in recent years. To ensure both non-halogenation of polymer materials and flame resistance, it is necessary to increase amounts of additives. However, that raises problems to polymer materials such as increased weight, reduced flexibility and higher brittleness. To overcome these issues, nanocomposites were applied to vehicle floor sheet. The nanocomposites are contained highly dispersed nano-level (10-9 m) fine particles, and have the advantage of improving a number of performances, including flame resistance, from the simple addition of a small amount of fine particles.
Through investigation of an application of the nanocomposites to the floor sheet, it is apparent that the flame resistance when laminated on a floor sheet surface was excellent (Fig. 1). A surface laminated product using the nanocomposites satisfied the flame-retardancy that is required of floor sheet according to ministerial ordinances. Its mechanical properties also satisfied the specifications prescribed by the old JRS, it was confirmed that its applicability as a floor sheet for vehicles was confirmed (Table 1). As the material also has a lower density, the weight per unit area can be reduced by 50% or more compared with conventional floor sheet for vehicles.