JPH08289805A - Production of cup insole for shoes - Google Patents

Abstract

PURPOSE: To obtain a cup insole for shoes which obviate the sweaty feet, retains the original thickness without reduction by the body weight and has sufficient strength. CONSTITUTION: This cup insole for shoes is obtd. by kneading 70 to 130 pts.wt. polyamide fibers with 100 pts.wt. thermoplastic synthetic resin or thermoplastic rubber under application of shearing force, forming the mixture to a sheet form, heating the sheet in hot air, adhering and superposing an open cellular synthetic resin and cloth atop this sheet and press molding the laminate by means of molds.

Description

Detailed Description of the Invention

The present invention relates to a method for producing a shoe cup insole which does not get stuffy, does not become thin, and does not deteriorate in elasticity.

[0002]

2. Description of the Related Art Shoe cup insoles are made of various materials and structures. The most typical example is a non-woven fabric made of polyester, or a thermoplastic synthetic resin foam made of ethylene / vinyl acetate copolymer, polyethylene, etc., overlaid with a woven fabric such as polyester fiber or recycled fiber, and then heated and softened. Then, it is put into a mold cavity, pressed, cooled, and then molded into a desired shape.

[0003]

Among the conventional companion insoles, the one in which the base material is a non-woven fabric causes a large strain due to the weight during use, becomes thin, loses softness and elasticity, and impairs the wearing comfort. I often hurt my toes. Also, most of the thermoplastic resin foam base materials are poorly permeable and moisture permeable because they are single foams, they easily steam during use, and in the case of ethylene-vinyl acetate copolymer, However, there is a drawback that the temperature inside the shoe tends to be softened due to the body temperature, the thickness is reduced to half, the strength is reduced, and the shoe may be broken at the time of putting on and taking off or coming out by the shoe. SUMMARY OF THE INVENTION The present invention aims to solve all the drawbacks of the conventionally used cup insoles all at once.

[0004]

The present invention includes the following (a)-
The method of manufacturing a cup insole for shoes comprising the step (d) is characterized. (A) 100 to 100 parts by weight of thermoplastic synthetic resin or thermoplastic rubber is kneaded with 70 to 130 parts by weight of polyamide fiber while applying a shearing force. (B) The kneaded product obtained in the step (a) is rolled into a sheet. (C) The sheet obtained in the step (b) is placed in hot air and expanded. (D) On the upper surface of the expansion sheet obtained in the step (c), the open-cell synthetic resin sheet and the cloth are sequentially superposed with an adhesive, put into a mold, and the resin sheet is softened by heating. After that, it is put in a mold and pressed to cool.

In carrying out the present invention, an ethylene vinyl acetate copolymer having a vinyl acetate content of 25 to 33% as measured by infrared analysis is used, and the vinyl acetate content is 2%.
If it is less than 5%, it cannot be mixed with the polyamide fiber, and if it exceeds 33%, the elasticity of the finished cup insole is lost. As the thermoplastic rubber, a styrene / butadiene copolymer rubber, a polyolefin rubber, which is easily molded into the shape of a cup insole in a mold and has elasticity,
Alternatively, for high trans-1.4-polyisoprene is used.

The above-mentioned thermoplastic synthetic resin and thermoplastic rubber are used as a blend, and the former is mainly used to improve moldability in a mold. The blended body contains 70 to 100 polyamide fibers per 100 parts by weight.
Parts by weight are mixed. Polyamide fiber is easy to knead and disperse in the steps such as kneading with a blended body and heating, and stretching,
This is because it is easy to receive the crimping action, and it is easy to make the whole bulky,
However, if the amount is less than 70 parts by weight, the bulkiness may not be sufficient, and if it exceeds 130 parts by weight, the amount of the blended body also serving as the binder is too small, and the fibers are lumped and dispersed. It becomes impossible, and it becomes difficult to form a sheet. As the adhesive, a hot melt adhesive that exhibits tackiness (or adhesiveness) when heated in a mold is used.

[0007]

When 100 to 100 parts by weight of the thermoplastic synthetic resin or the thermoplastic rubber and 70 to 130 parts by weight of the polyamide fibers are kneaded with a shearing machine while applying a shearing force, the polyamide fibers are dispersed in an expanded state. When the sheet is made into a sheet shape, its stretched state is further promoted, and when heated by hot air in such a state, the synthetic resin or rubber is in a thermoplastic state, so that the synthetic resin or rubber is in a fluidized state and the tension of the fiber is increased. The stretched state subjected to the stress is relaxed, and conversely, the crimped state is formed, and voids are formed and at the same time, the state becomes bulky, which is 3 to 5 times as bulky as that before the treatment. In this way, breathability and a felt-like appearance and elasticity are provided.

This felt-like sheet is placed on the upper surface of the sheet with an open-cell synthetic fiber sheet, cloth, etc., and placed in a mold.
In the process of heating, pressing, cooling, etc. when molding into a cup insole, since the synthetic resin rubber and the like that is the base is thermoplastic, the shape of the mold, the design, etc. are faithfully given,
A cup insole with excellent shape and appearance can be obtained.

Further, the polyamide fiber functions as a reinforcing agent after molding, and at the same time, the function of a spring when weight is exerted can be revealed together with the synthetic resin and the rubber. At the same time, it is possible to prevent fatigue. Furthermore, the open-cell synthetic resin sheet that is overlaid on the upper surface of the felt-like sheet is usually
Polyurethane is used to help impart a comfortable elasticity to the sole of the foot. The uppermost cloth is made of natural fibers, recycled fibers, etc., which have good hygroscopicity, and not only improves the comfort of wear, but also can be deodorized and antibacterial when treated with a given chemical.

[0010]

EXAMPLE 100 parts by weight of ethylene vinyl acetate copolymer (vinyl acetate content 30%), 10 parts by weight of natural rubber, 100 parts by weight of polyamide fiber (diameter 20 denier, length 15 mm), 2.0 parts by weight of pigment The mixture was kneaded for 30 minutes with an open roll machine at a temperature of 40 ° C. ±, and sheeted to a thickness of 0.7 mm. A 4.5 mm-thick open-cell polyurethane sheet was laminated on the upper surface of this sheet with a hot-melt adhesive made of ethylene vinyl acetate copolymer, and a natural fiber woven fabric was further laminated on the upper surface thereof with the same adhesive, 130-16
It was placed in a hot air circulation type oven at 0 ° C. for 5 minutes and expanded about 3 times. This inflatable sheet was placed in a mold of 150 cup insoles at 150 ° C., the mold was clamped at 70 kg / cm ^{2 for} 2 minutes, then cooled at 150 ° C., taken out of the mold and cut (10 pieces each on each side). ) Cup insoles were obtained.

[0011]

[Effect] The cup insole for shoes obtained by the manufacturing method of the present invention has good breathability, so that it does not cause foot stuffiness and does not become thin due to body weight. Therefore, the initial elasticity is always maintained and the comfort of wearing is improved. It will not be damaged and has sufficient strength so that it will not break when coming on and taking off or come out of the shoe.

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Claims (5)

[Claims] 1. A method for producing a cup insole for shoes, which comprises the following steps (a) to (d): (A) 70 to 130 parts by weight of polyamide fiber is kneaded with 100 parts by weight of thermoplastic synthetic resin or thermoplastic rubber while applying shearing force. (B) The kneaded product obtained in the step (a) is rolled into a sheet. (C) The sheet obtained in the step (b) is placed in hot air and expanded. (D) On the upper surface of the expansion sheet obtained in the step (c), the open-cell synthetic resin sheet and the cloth are sequentially superposed with an adhesive, put into a mold, and the resin sheet is softened by heating. After that, it is put in a mold and pressed to cool. 2. The method for producing a cup insole for shoes according to claim 1, wherein the thermoplastic synthetic resin is an ethylene vinyl acetate copolymer having a vinyl acetate content of 25 to 33% measured by infrared analysis. 3. The thermoplastic rubber is styrene / butadiene block copolymer rubber, polyolefin copolymer rubber, or high trans 1.4-polyisoprene.
Manufacturing method of the cup insole for shoes described. 4. The method for producing a cup insole according to claim 1, wherein the thermoplastic synthetic resin is a blend of thermoplastic rubbers of less than equal amount. 5. The method for producing a cup insole for shoes according to claim 1, wherein the sheet obtained in the step (C) is expanded 3 to 5 times in thickness as compared with that before heating.