Shoe inner sole reinforced at back by heel pieces - is made from cardboard impregnated with plastic material

摘要

The shoe inner sole has a central element, made in leather or cellulose fibres joined to latex. The element is reinforced at its back curved part by two heel pieces. These are made from cardboard that is impregnated with thermo-malleable plastic material, pref. polyethylene. The inner sole is made by pre-gluing the heel pieces and the central element with a thermoactive adhesive whose activation temp. is near the softening temp. of the cardboard. The heel pieces are pre-heated and put in place on a shoe-shaped punch and then pressed together and cooled. (12p).