| abstract |
Methods and systems for forming hinged starch-bound matrices. Starch-based compositions are molded between heated molds in order to form a cellular matrix and also to remove the water from the starch-based compositions in order to form a binding matrix of solidified starch. The molding apparatus is configured to form one or more creases within the hinge area in order to define one or more lines upon which the hinge will bend. The molding apparatus is also configured such that the region of the mold corresponding to the inner surface of the hinge area will transfer heat more slowly to the inner hinge surface, resulting in reduced thickness of the skin of the inner hinge. This increases the collapsibility, or ability of the inner surface of the hinge to fold or buckle, during the bending action. This in turn reduces the bending radius of hinge such that the hinging action exerts less strain on the outer surface of the hinge. The inner surface of the hinge may optionally be treated with glycerin or other polyols soften the inner surface. The outer surface of the hinge may optionally be coated with an elastomeric material, such as polyvinyl alcohol, in order to strengthen the outer surface and reduce its tendency to fracture during the hinging action. |