JPH074289B2 - Method for manufacturing shoe soles having different hardness - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing shoe soles having different hardness.

[0002]

2. Description of the Related Art Conventionally, by partially configuring the shoe sole to have different hardness, the cushioning property and the shock absorbing property are partially enhanced, and the heel part is overloaded or the tread part is overloaded. Outsole soles are generally known. When molding these shoe soles, the shoe sole members that have been molded with different hardness in advance are joined with an adhesive, or the molding materials that have been set to different hardness in advance are set in the mold, and different Since a method of performing insert molding integrally with a portion of the shoe sole mainly when molding a shoe sole having a high hardness was adopted, the process was complicated and the cost was extremely high.

[0003]

SUMMARY OF THE INVENTION The present invention is intended to provide, at a low cost, an integrally molded shoe sole having a partial hardness difference by a simple method.

[0004]

Hereinafter, the present invention will be described with reference to the drawings showing the embodiment of the present invention.
1 which is densely formed and foamed the inner layer 12
The gist of the invention is a method for manufacturing a shoe sole having a hardness difference, which is characterized in that the outer layer 11 is partially removed.

In the present invention, the shoe sole material 1 is composed of ordinary shoe sole materials such as rubber, vinyl chloride, EVA, polyurethane and the like. When the shoe sole material 1 is made of a crosslinkable material such as rubber, EVA, or polyethylene, for example, by appropriately combining a crosslinking agent and a foaming agent during compounding, the crosslinking of the outer layer 11 is foamed during molding. The outer layer 11 may be densely molded, and the inner layer 12 may be foamed prior to crosslinking. When it is made of a thermoplastic material such as vinyl chloride, 1.2 polybutadiene, or styrene-butadiene block copolymer, it is injected into a reduced mold cavity by, for example, a full shot method, and then the mold is cooled. Then, the outer layer 11 in contact with the mold is cooled to a temperature below the softening point to form a dense layer, and then the mold cavity is expanded to foam the inner layer 12. Further, in the present invention, when the shoe sole 1 is made of polyurethane, the liquid polyurethane is moistened at room temperature or at 40 to 50 ° C.
If the inner layer 12 is foamed and molded, and the outer sole material 11 having a dense outer layer 11 of about 1 to 3 mm can be molded on the outer side, it is convenient to mold the shoe sole material 1 by molding. In the foamed shoe sole material 1 molded in this way, the outer layer 11 is a dense hard layer having a high apparent density, and the inner layer 12 is multi-foam and has a low apparent density and is flexible and cushioning. Become a rich layer. Therefore, if the outer layer 11 is removed by using a grinder or a shaving machine and the inner layer 12 is exposed on the surface at a portion requiring a hardness difference, that is, a partially low hardness, this exposed portion is exposed. In, the surface hardness can be reduced corresponding to the inner layer 12.

In the present invention, the foam sole material 1 may be formed in a flat plate shape, or a portion requiring a difference in hardness, that is, a portion having a low hardness, may be partially formed by protrusion, and the protrusion may be grindered. -If the inner layer 12 is exposed to the surface by removing using a skitting machine, the dense hard portion formed of the outer layer 11 and the low hardness portion formed of the inner layer 12 can be formed in the same plane. So convenient.

[0007]

As described above, according to the present invention, the outer layer 11 is densely formed by the conventional method, and the shoe sole material 1 in which the inner layer 12 is foam-molded is partially formed by the grinder and the ski machine. Since it is possible to provide a shoe sole having a hardness difference by simply removing the inner layer 12 and exposing the inner layer 12, a shoe sole material having a different hardness can be formed in advance as in the conventional case, or a shoe sole material having a different hardness can be molded. Since it is not necessary to insert-mold into the mold, the manufacturing is simple and the cost is low.

[0008]

EXAMPLE A midsol material having a thickness of 10 mm was molded by a conventional casting method using a foamable liquid polyurethane, and the thickness was set on the inner side of the upper surface of the stepping portion with the center portion 01 as the apex. Is 3 mm, and the outer circumference 21 thereof is projected by 3 mm from the outer surface of the midsole, and an arc-shaped projection 2 is formed integrally with the midsole. The shoe sole molding material 1 for a midsole molded in this way is composed of a dense outer layer portion 11 having an average thickness of 2.5 mm and a density of 0.95 and an inner layer 12 foamed at a density of 0.35. It was. The arc-shaped protruding portion 2 of the shoe sole material 1 thus formed is removed by a grinder, and the inner layer 12 is exposed in an arc shape with the substantially central portion 01 as the apex on the inner side of the upper surface of the tread. Let In the midsole thus formed, the hardness of the inner side of the upper surface of the stepping part where the inner layer 12 is exposed is 10% lower than the other parts in sponge hardness according to SRIS0101, and has excellent cushioning properties. It was effective in preventing excessive supination of the foot in the stepped part during walking.

[Brief description of drawings]

FIG. 1 is a sketch prior to the partial removal of the outer layer.

FIG. 2 is a sketch of a shoe sole with an outer layer partially removed.

FIG. 3A. It is sectional drawing in the XX line of FIG. B. It is sectional drawing in the YY line of FIG.

[Explanation of symbols]

 1. Sole material 11 ... Outer layer 12 ... Inner layer

Claims (1)

[Claims] 1. An outer layer 11 is densely formed and an inner layer 12 is formed.
A method for manufacturing a shoe sole having a hardness difference, characterized in that the outer layer 11 of the shoe sole material 1 formed by foaming is partially removed.