Methods for manufacturing footwear stiffeners
AssigneeStanbee Company, Inc.
InventorsDale Martell, Bruce Goldberg, Leo Provencher
Life of this patent
Estimating the term…
Abstract
A method is provided for making a microcellular shoe stiffener has first and second adhesive layers coextruded on opposite first and second surfaces of a stiffener core. The stiffener core may include a recycled polymeric material. Nitrogen in a supercritical fluid state is introduced into the extruder for the stiffener core to produce a closed cell foam with a gaseous component. The gas reduces the weight and cost of the stiffener without significantly reducing stiffness and resiliency.
Claims10
A method for manufacturing a microcellular foam box toe shoe stiffener material or heel counter shoe stiffener material, comprising:
- extruding a polymeric material from an extruder to form a stiffener core that has opposite first and second surfaces defining a thickness in a range of about 0.55 mm to about 1.99 mm;
- extruding first and second adhesive layers onto the first and second surfaces of the stiffener core;
- and
- calendering the first and second adhesive layers onto the first and second surfaces of the stiffener core to produce the stiffener material, wherein
- the step of extruding the polymeric material from the extruder comprises introducing nitrogen in a super critical fluid state into the extruder so that the stiffener core is a closed cell foam that includes a nitrogen gas in an amount so that the nitrogen gas is about 0.015% to about 0.028% by weight of the stiffener core thereby reducing a weight of the box toe shoe stiffener material or heel counter shoe stiffener material.
Dependencies are inferred from the claim text.