Composite material having polypropylene foam layer

摘要

A composite material having a skin layer, an intermediate, cushioning layer provided on one side of the skin layer, and a backing layer provided on the cushioning layer, wherein the backing layer is made of a non-crosslinked polypropylene resin foam and having a melting point MB in the range of 130-170 DEG C., wherein the cushioning layer is a crosslinked polypropylene resin foamed sheet having a gel fraction of 20-70% by weight. The cushioning layer has an endothermic peak in DSC curve at a peak temperature of PC which is in the range of 130-170 DEG C. and which is not smaller than (MB-15) DEG C. but not greater than (MB+10) DEG C. The endothermic peak has such an area at temperatures higher than MB that corresponds to a calorific value in the range of 3-30 J/g. The backing layer may be formed by expansion molding of expanded polypropylene particles within a mold cavity in which a laminate of the skin layer and the cushioning layer is placed in position.