Method of manufacturing a molding for energy absorbent pads and mold used in the method

A mold for manufacturing a rigid polyurethane foam molding by introducing a rigid polyurethane foam raw material composed primarily of a polyhydroxy compound and a polyisocyanate compound into a cavity defined by separatably joining an upper die and a lower die, and blowing and reacting said rigid polyurethane foam raw material in said cavity, wherein:

• said lower die has a lower die cavity for blowing said cavity when said upper die and said lower die are joined together;
• a fine space is defined at an outer circumferential edge of an upper end of said lower die cavity so as to communicate with said lower die cavity;
• said upper die has a hollow chamber so as to communicate with said cavity through said fine space;
• and
• an air pipe is connected at one end thereof to said upper die so as to communicate with said hollow chamber and connected at the other end to an air suction device;
• whereby said rigid polyurethane foam raw material is introduced into said cavity and said air suction device is operated to evacuate said cavity through said air pipe, said hollow chamber, and said fine space, to blow and react said raw material, thereby forming said rigid polyurethane foam molding with a core portion having a pack ratio ranging from 0.5 to less than 1.2.