JP2750670B2 - How to make cup insoles for shoes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for producing a cup insole for shoes, which does not produce stuffiness, does not become thin, and does not lose elasticity.

[0002]

2. Description of the Related Art Various types of materials and structures are used for cup insoles for shoes. The most typical one is made by laminating a woven fabric such as polyester fiber and recycled fiber on a non-woven fabric made of polyester or a thermoplastic synthetic resin foam made of ethylene-vinyl acetate copolymer or polyethylene, heating and softening. After that, it is put into a mold cavity, pressed, cooled, and then molded into a desired shape.

[0003]

In the above-mentioned conventional cam insole, when the base material is a non-woven fabric, a large strain is caused by the weight during use, it becomes thin, loses softness and elasticity, and impairs comfort. He often hurt his heels. In addition, when the base material is a thermoplastic synthetic resin foam, since most of the foam is a single foam, it is poor in air permeability and moisture permeability, easily stuffy during use, and in the case of an ethylene-vinyl acetate copolymer, However, there is a disadvantage that the temperature in the shoe is easily softened due to a rise in temperature due to body temperature, the thickness is reduced by half, the strength is reduced, and the shoe is broken at the time of attachment / detachment or comes out of the shoe. An object of the present invention is to solve many of the drawbacks of the conventionally used cup insoles at once.

[0004]

The present invention provides the following (a) to (d):
The method is characterized by a method for producing a shoe cup insole comprising the step (d). (A) 70 to 130 parts by weight of a polyamide fiber is kneaded with 100 parts by weight of a thermoplastic synthetic resin or a thermoplastic rubber while applying a shearing force. (B) The kneaded material obtained in the step (a) is rolled into a sheet. (C) The sheet obtained in the step (b) is put into hot air and expanded. (D) The open-cell synthetic resin sheet and the cloth are successively stacked on the upper surface of the expanded sheet obtained in the step (c) via an adhesive, placed in a mold, and the resin sheet is softened by heating. Then, it is put into a mold, pressed, and cooled.

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 resulting cup insole is lost. As the thermoplastic rubber, styrene-butadiene copolymer rubber, polyolefin rubber, and the like, which are easily formed into a cup insole shape in a mold and have elasticity, can be used.
Alternatively, a high trans-1.4-polyisoprene type is used.

The thermoplastic synthetic resin and the thermoplastic rubber are used by blending, and the former is mainly used to improve moldability in a mold. In the blend, the polyamide fiber is 70 to 100 parts by weight based on 100 parts by weight.
Parts by weight. Polyamide fibers are easily kneaded and dispersed in processes such as kneading with a blend and heating.
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, sufficient bulk cannot be obtained. If the amount exceeds 130 parts by weight, the amount of the blend that also serves as the binder is too small, so that the fibers are aggregated and dispersed. It becomes impossible, and it becomes difficult to form a sheet. As the adhesive, a hot melt adhesive which exhibits tackiness (or adhesiveness) by heating in a mold is used.

[0007]

When polyamide fiber is kneaded with, for example, a roll machine while applying a shearing force of 70 to 130 parts by weight of polyamide fiber to 100 parts by weight of thermoplastic synthetic resin or thermoplastic rubber, the polyamide fiber is dispersed in an expanded state. In the form of a sheet, the stretched state is further promoted, and in such a state, when heated by hot air, the synthetic resin or rubber is thermoplastic, so that it is in a fluid state, and the tension of the fiber is increased. Is relaxed, conversely crimped, and voids are formed and at the same time become bulky, which is 3 to 5 times larger than before treatment. In this way, breathability, felt-like appearance and elasticity are imparted.

[0008] The felt-like sheet is placed on an upper surface thereof with an open-cell synthetic fiber sheet, a cloth or the like, and placed in a mold.
In the steps of heating, pressing, cooling, etc., when molding into a cup insole, the synthetic resin rubber, etc., which is its base, is thermoplastic, so that the shape, design, etc. of the mold are given faithfully,
A cup insole with excellent shape and appearance can be obtained.

In addition, the polyamide fiber functions as a reinforcing agent after molding, and at the same time, the function of a spring when a weight is applied can appear in combination with the synthetic resin and rubber. At the same time, settling and the like can be prevented. Furthermore, the open-cell synthetic resin sheet superimposed on the upper surface of the felt-like sheet is usually
Polyurethane is used to help provide comfortable elasticity to the soles. The fabric in the uppermost layer is made of natural fibers, regenerated fibers and the like having good hygroscopicity, and can not only improve comfort, but also can perform deodorant and antibacterial functions when treated with a given agent.

[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 (20 denier in diameter, 15 mm in length), and 2.0 parts by weight of pigment The mixture was kneaded with an open roll machine at a temperature of 40 ° C. ± 30 minutes and sheeted to a thickness of 0.7 mm. A 4.5 mm thick open-cell polyurethane sheet is laminated on the upper surface of this sheet via a hot-melt adhesive made of ethylene vinyl acetate copolymer, and a natural fiber fabric is further laminated on the upper surface thereof via the adhesive. 130-16
It was placed in a hot air circulating oven at 0 ° C. for 5 minutes and expanded about three times. This inflatable sheet is placed in a 150 ° C. mold having 10 cup insoles, clamped at 70 kg / cm ^{2 for} 2 minutes, then cooled at 150 ° C., removed from the mold and cut, and 10 sheets (5 sheets each on the left and right sides) ) Cup insole was obtained.

[0011]

The shoe insole obtained by the method of the present invention has good air permeability, so that the foot does not get stuffy and does not become thin due to weight, so that the original elasticity is always maintained and the comfort is improved. It is not damaged, and has sufficient strength, so that it does not break or slip out of shoes when attaching or detaching.

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Claims (5)

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