Injection physical foaming inner boot and method of manufacturing inner boot by injection physical foaming

1 . An injection physical foaming inner boot, comprising:

a foot portion, comprising a forefoot section and a hindfoot section, wherein a hardness of the forefoot section is greater than a hardness of the hindfoot section; and

a shaft portion, extending upwards from the hindfoot section of the foot portion, wherein the foot portion and the shaft portion are integrally formed; both the foot portion and the shaft portion include a thermoplastic material and do not include a crosslinking agent and a chemical foaming agent; both a specific gravity of the foot portion and a specific gravity of the shaft portion range between 0.1 g/cm 3 and 0.3 g/cm 3 ; the hardness of the forefoot section is greater than a hardness of the shaft portion;

an inner layer, wherein the inner layer comprises an inner foot section and an inner shaft section; the inner foot section is correspondingly engaged with an inner surface of the foot portion; the inner shaft section is correspondingly engaged with an inner surface of the shaft portion, wherein an extensible region and an inextensible region are defined on the inner layer; the extensible region is distributed on a part of the inner shaft section and a part of the inner foot section, the inextensible region is distributed on another part of the inner shaft section and another part of the inner foot section; an area of the inextensible region of the inner shaft section is less than an area of the extensible region of the inner shaft section; an area of the inextensible region of the inner foot section is less than an area of the extensible region of the inner foot section; the inextensible region of the inner shaft section is larger than the inextensible region of the inner foot section; and

at least one reinforcement member disposed on an outer surface of at least one of the shaft portion or the foot portion, when the at least one reinforcement member is fixed on the outer surface of the shaft portion, the at least one reinforcement member is fixed on the shaft portion through sewing and is engaged with the inextensible region of the inner layer; when the at least one reinforcement member is fixed on the outer surface of the foot portion, the at least one reinforcement member is fixed on the foot portion through sewing and is engaged with the inextensible region of the inner layer.

2 . The injection physical foaming inner boot as claimed in claim 1 , wherein the inner layer is a fabric, the inner layer has a plurality of first pores distributed no the inner foot section; the inner layer has a plurality of second pores distributed on the inner shaft section; a part of the foot portion enters the plurality of first pores of the inner foot section; a part of the shaft portion enters the plurality of second pores of the inner shaft section; no adhesive layer is provided between the inner foot section and between the inner shaft section and the shaft portion.

3 . The injection physical foaming inner boot as claimed in claim 1 , further comprising an anti-slip member, wherein the anti-slip member is disposed on the foot portion of the injection physical foaming inner boot; the foot portion has an upper and a sole; the upper is connected to the periphery of the sole; the anti-slip member is engaged with a bottom surface of the sole of the foot portion.

4 . The injection physical foaming inner boot as claimed in claim 1 , wherein the thermoplastic material is selected from a group consisting of polyolefin, polyester, thermoplastic polyurethane (TPU), nylon, and a combination thereof.

5 . The injection physical foaming inner boot as claimed in claim 1 , wherein the thermoplastic material of the forefoot section, the hindfoot section, and the shaft portion are identical; an average thickness of the forefoot section is less than an average thickness of the hindfoot section and less than an average thickness of the shaft portion, such that a pore density of the forefoot section generated by foaming is high and a pore density of both the hindfoot section and the shaft portion generated by foaming are less than the pore density of the forefoot section.

6 . The injection physical foaming inner boot as claimed in claim 1 , wherein a hardness of the thermoplastic material of the forefoot section is greater than a hardness of the thermoplastic material of the hindfoot section and greater than a hardness of the thermoplastic material of the shaft portion.

7 . The injection physical foaming inner boot as claimed in claim 2 , wherein a tensile strength of the inextensible region is greater than a tensile strength of an extensible region.

8 . The injection physical foaming inner boot as claimed in claim 7 , wherein the extensible region and the inextensible region are woven materials comprising different fibers.

9 . The injection physical foaming inner boot as claimed in claim 7 , wherein the and the inextensible region are woven materials comprising different weaving patterns.

10 . The injection physical foaming inner boot as claimed in claim 2 , wherein the inner layer is provided with fabric loops on both the inner foot section and the inner shaft section, improving engagement strengths between the inner layer and the foot portion and between the inner layer and the shaft portion.

11 . The injection physical foaming inner boot as claimed in claim 3 , wherein the anti-slip member comprises a plurality of anti-slip blocks.

12 . The injection physical foaming inner boot as claimed in claim 11 , wherein the plurality of anti-slip blocks correspond to and are disposed in a plurality of recesses distributed on the bottom surface of the sole and protrude outwards relative to the bottom surface of the sole.

13 . The injection physical foaming inner boot as claimed in claim 1 , wherein the physical foaming imparted by a supercritical fluid.

14 . The injection physical foaming inner boot as claimed in claim 13 , wherein the supercritical fluid comprises nitrogen or carbon dioxide.