JPH05293003A - Method for manufacturing sole having hardness difference - Google Patents

Abstract

PURPOSE:To manufacture a sole having the hardness difference with a low cost by producing the sole formed of the foaming agent formed inner layer overlaid with the minutely formed outer layer and removing partially the outer layer. CONSTITUTION:When a sole material 1 is composed of a usual cross-linkable material of rubber, polyvinyl chloride, EVA, polyurethane, etc., for example, it is molded by properly combining the bridging materal and foaming agent in blending. The cross-linking of the outer layer 11 is adapted to preceed foaming to form minutely the outer layer 11, and the inner layer 12 is adapted to foam before cross-linking. The outer layer 11 in the part needing partially low hardness is removed by the use of a grinder or carder to expose the surface of the inner layer 12. Thus, the sole having the partial hardness difference is manufactured with a low cost and the over-turnabout of feet in the tread in walking is effectively prevented.

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, shoe sole members that have been molded with different hardness in advance are joined with an adhesive, or molding materials that have been set to different hardness in advance are set in a mold and these Since a method of integrally performing insert molding on the main part of the shoe sole was adopted when the main part of the shoe sole having high hardness was formed, 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 partial hardness differences 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 which is formed by foaming the inner layer 12 1
The present invention is directed to a method for manufacturing a shoe sole having a hardness difference, which is characterized in that the outer layer 11 of the above 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 outer layer 11 is crosslinked by foaming. 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 not higher than 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 kept at room temperature or at 40 to 50 ° C.
It is convenient that the inner layer 12 can be foamed and molded, and the shoe sole material 1 having the dense outer layer 11 of about 1 to 3 mm can be molded on the outer side of the inner layer 12 by foaming. In the foamed shoe sole material 1 thus formed, the outer layer 11 is a hard layer having a high density and 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 where a hardness difference, that is, a partly low hardness is required, this exposed portion is exposed. In, the surface hardness can be reduced corresponding to the inner layer 12.

In the present invention, the foam shoe sole material 1 may be formed in a flat plate shape, or a portion requiring a hardness difference, that is, a portion having a low hardness, may be formed by partially protruding, and the protruding portion may be grindered. -, If the inner layer 12 is exposed to the surface by removing with a shaving machine, the dense hard part composed of the outer layer 11 and the low hardness part composed 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 skiing machine. Since it is possible to provide a shoe sole having a hardness difference only by removing the inner layer 12 to expose the inner layer 12, a shoe sole material having a different hardness can be formed in advance, 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 is molded by a conventional casting method using a foamable liquid polyurethane, and a thickness of about 100% is formed on the inner side of the upper surface of the stepping portion with the center portion 01 being 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 formed in this way, 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 is excellent in 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 before 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.