JPH0568603A - Production of shoes - Google Patents

Abstract

PURPOSE:To provide the process for production of the shoes which have good adhesiveness of both soles and have good appearance by simple stages in the process for production of the shoes having the outer sole consisting of two layers consisting of natural leather as the lower sole and expandable polyurethane as the upper sole. CONSTITUTION:The lower sole made of the natural leather to be imposed in the cavity of a lower mold is formed by using the upper sole bonded with a cloth having low hygroscopicity on the adhesive surface of the sole, injecting the liquid expandable polyurethane atop this sole, combining a last pulled over with uppers with the above-mentioned mold and heating the last to foam and cure the liquid expandable polyurethane in the cavity. Then, (1) the adhesion of the upper sole and the lower side is sufficient. (2) The expandable polyurethane forming the upper sole does not contaminate the lower sole. (3). The outer sole does not 'warp'. (4) A 'play' does not arise in the mouth of the shoes. (5) Labor and time are not so much spent in the production process of the shoes.

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 a shoe having a natural leather as a lower sole and an outer sole having two layers of foamed polyurethane as an upper sole.

[0002]

2. Description of the Related Art In shoes used for sports such as sports, the lower sole (ground contact sole), which constitutes a part of the outer sole, often requires proper sliding with respect to the floor surface.
For example, during a bowling ball competition, shoes using natural leather for the lower sole are prized for the above reasons. In such shoes, in order to further improve the appearance and to make them lighter and to improve the wearing comfort, the outer sole, the lower sole is natural leather as described above, and the upper sole is a two-layer structure made of foamed polyurethane. Was used.

[0003]

However, since natural leather absorbs a large amount of water, when the liquid foamed polyurethane is injected into the upper surface of the lower leather as it is and molded, the water content of the foamed polyurethane is It reacted and acted as a foaming agent, inhibiting the adhesion between the upper and lower bottoms of the formed outsole. Therefore, immediately before placing it inside the lower mold cavity, the lower bottom natural leather is treated, for example, in a drying chamber at 60 ° C. for about 30 minutes to remove moisture, or is bonded to eliminate the influence of moisture. The work of applying the agent several times was performed.

As described above, when the natural leather for the lower sole is dried to remove water, shrinkage of several percent occurs, and at the same time, a so-called "warpage" phenomenon is observed, and in the process of forming the outer sole, the upper sole is formed. The foamed polyurethane that forms the bottom part of the bottom of the bottom part of the bottom part of the bottom part of the bottom part of the bottom part, covering a part of the bottom part of the bottom part, causing defective products. The natural leather for use absorbs moisture in the air, and the size of the shoe rises, causing the toe spring of the shoe to rise, causing the mouth to spread laterally, causing so-called "laughing", which also deteriorated the appearance. .. In addition, the method of applying the adhesive to the upper surface of the lower bottom natural leather requires several times of application in order to minimize the influence of moisture. Specifically, each coating must be placed in a drying chamber at 60 ° C for 5 minutes, and even if sufficient time is taken until the step of forming the outer bottom in this way, some " It was inevitable to avoid "warping", so that it was unavoidable that the foamed polyurethane forming the upper bottom slightly wrapped around the lower surface of the lower bottom. The present invention aims to solve the above problems.

[0005]

According to the present invention, a lower bottom made of natural leather having a small hygroscopic fabric adhered to the upper surface is placed at a predetermined position of a lower mold cavity so as not to move, and a liquid is placed on the upper surface. The gist of the invention is to inject polyurethane foam and combine a shoe mold in which the instep is suspended with the lower mold, and heat to form an outsole and at the same time, adhere to the lower surface of the instep.
Here, as the cloth having low hygroscopicity, polyester,
A woven fabric such as a short fiber such as polyamide or a long fiber, or a non-woven fabric is used, and as a method for adhering these fabrics to the upper surface of the lower bottom made of natural leather, polyurethane, polyamide,
A method such as thermocompression bonding using a hot-melt plastic such as ethylene / vinyl acetate copolymer or a method using a solvent paste obtained from polychloroprene rubber may be appropriately used.

[0006]

In the present invention, the natural leather used for the lower sole is not dried, and therefore, even if it contains water, there is a cloth having a low hygroscopicity on the surface which is bonded to the polyurethane for the upper sole. Therefore, the moisture contained in the natural leather does not come into contact with the polyurethane during the foaming / curing process, and therefore, the lower bottom and the upper bottom that form the outer bottom after being molded. It does not hinder the adhesion with. In addition, the outer bottom having a good appearance can be obtained without causing dimensional change or “warpage”.

[0007]

Example: A polyurethane hot melt adhesive is applied to ester gins, dried, and then superposed on the upper surface of the lower bottom made of natural leather, which has a shape similar to that of the outer sole, and is heated at 150 ° C. on a heat roller type press. A pressure of ² kg / cm ² was applied between the plates for 10 seconds. An outer bottom lower mold having a partition wall of the same shape as the lower bottom is prepared on the bottom of the cavity, the lower bottom is fitted in the partition wall, and butylene adipate polyester polyol, 1.4-butane is placed on the upper surface of the lower bottom. Liquid polyurethane foam containing diol and methylene diisocyanate as main components is injected so that the specific gravity after curing becomes 0.6, and a shoe mold with the instep hung is combined and heated at 40 ° C for 5 minutes to foam polyurethane. At the same time as curing, the molded outer sole was adhered to the lower surface of the instep to obtain a predetermined shoe.

This shoe was used as the shoe obtained according to the present invention, and at the same time, the shoe obtained by using natural leather as it was for the lower sole was used as Control Example 1, which was treated in a drying room at 60 ° C. for 30 minutes, as the lower sole. The obtained shoe was used as Control Example 2, and a shoe obtained by applying polyurethane solvent glue to the upper surface four times as the lower sole was used as Control Example 3, and the upper sole and the lower portion constituting the outer sole of each shoe. Adhesion with bottom (kg / cm) (JIS K
6301 vulcanized rubber physical test method), deformation of outer sole and appearance were examined. The present invention Control example 1 Control example 2 Control example 3 Adhesive strength 5.2 0.1 4.5 4.3 No deformation No shrinkage, large amount of warpage Small amount of warpage Appearance Good Good Part of the bottom surface of the bottom bottom Part of the bottom surface of the bottom bottom is covered by the top bottom .. Was slightly covered by the upper bottom.

[0009]

[Advantages of the Invention] Adhesive force between the upper sole and the lower sole constituting the outer sole of the shoe is sufficient, and the outer sole itself does not shrink or "warp", and a part of the lower sole is attached to the upper portion. A shoe with a good appearance was obtained without covering the bottom.

Claims (1)

[Claims] 1. A lower bottom made of natural leather having a small hygroscopic fabric adhered to its upper surface is placed on a predetermined portion of the lower cavity so as not to move, and liquid foamed polyurethane is injected onto the upper surface thereof to cover the upper shell. A method for manufacturing a shoe, characterized in that a shoe mold in which the above is suspended is combined with the lower mold and heated to form an outer sole and at the same time, adhere to the lower surface of the instep.