JPS6122801A - Production of shoes having foamed polyurethane sole - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a shoe having a foamed polyurethane outsole, and more particularly to a method for manufacturing a shoe having a foamed polyurethane outsole that has excellent functionality during running.

- Shoes with foamed polyurethane soles are, as is well known, manufactured with the aim of being lightweight and comfortable to wear.

However, recently, in addition to the above-mentioned properties, specific functions have become required when driving for long periods of time.

For example, when a person lands while running, he or she first lands on the heel, moves to the outside of the heel, moves through the external leg arching, moves to the medial side, and reaches the inside of the heel, resulting in a rolling phenomenon.

Especially when soft materials with low specific gravity are used, such as foamed polyurethane outsole, the rolling becomes too large, and if you continue to run for a long time, too much force is applied to the inside of the heel, and as a result, foamed polyurethane The inside of the heel of the outer sole becomes distorted, and unnatural force is applied to the legs and knees, damaging the feet.

In addition, when kicking off with the toe part when moving to the next landing while running, the treading part must necessarily be bent, so the treading part of the outer sole is soft and flexible. If you don't have something to wear, your legs will get tired quickly.

Therefore, when running for a long time, the outer sole of the shoes worn should be softer on the outside than the inside at the heel, and softer at the foot of the foot than the other parts in front and behind it. is desirable.

The same applies to the foamed polyurethane outsole, and for that purpose, a soft molded material is added to the outside of the heel of the outsole, or
A hard molded material may be embedded inside the heel part, and a soft molded material may be embedded in the stepping part.

Shoes with foamed polyurethane outer soles are manufactured by the unit tooling method and the direct tooling method. In the unit tooling method, only the foamed polyurethane outer sole is manufactured separately, and then this outer sole is attached to the lower surface of the shoe. The process is complicated because the shoes are obtained by gluing the
It is easy to carry out various operations when molding the foamed polyurethane outsole, and therefore it is easy to carry out the above-mentioned innovations, such as embedding molded bodies with specific properties in specific parts of the foamed polyurethane outsole. Necessary functions can be easily imparted to the foamed polyurethane outer sole.

On the other hand, when manufacturing shoes with foamed polyurethane outer soles using the direct tooling method, the process is simple because molding of the foamed polyurethane outer sole and adhesion to the underside of the shoe are performed at the same time. It is difficult to embed molded products with specific properties in specific locations on the polyurethane outsole, but it is difficult to manufacture shoes with the functions required during long-term driving using the direct tooling method. It had not been implemented.

The present invention uses a direct tooling method to embed molded bodies with specific properties in specific locations on a foamed polyurethane outer sole without complicating the process, thereby providing shoes with excellent functionality during running. The purpose is to combine a lower mold in which a liquid foamed polyurethane raw material is injected into the cavity for molding the outer sole, and a shoe last into which a shoe cover is suspended, and then heat and foam it. In the manufacturing method of shoes having a foamed polyurethane outer sole, the outer sole is formed by foaming and hardening the polyurethane raw material liquid, and at the same time the formed outer sole is adhered to the lower surface of the shoe. A molded body having desired properties is inserted by an appropriate method into a predetermined position of a closed cavity formed by combining a lower mold into which a foamed polyurethane raw material liquid is injected and a shoe last into which a shoelace is hung. This was achieved by creating a shoe with a foamed polyurethane outsole.

A method of inserting a molded body having desired properties into a predetermined position of the closed cavity of the lower mold as described above is to insert a molded body having desired properties into a predetermined position of the lower surface of the shoelace suspended in the last. It is advisable to glue the body together or to temporarily fix it slightly below the same point with a pin or the like provided upward on the lower surface of the lower mold cavity.

In the former case, the molded body having the desired properties is embedded in the outsole of the manufactured shoe with the upper surface in contact with the lower surface of the lace; in the latter case, the upper surface is in contact with the lower surface of the lace. It is not in contact with the bottom surface and is completely embedded in the outer sole.

At this time, for example, a molded material that is softer than the foamed polyurethane outer sole after foaming and hardening may be adhered to the outside of the heel on the lower surface of the shoelace, or a molded object made of foamed polyurethane after foaming and hardening may be attached to the inside of the heel on the lower surface of the shoelace. By gluing a molded material that is harder than the sole, the outside of the heel of the finished shoe will be softer than the inside, and the runner's heel will not tilt inward when landing, which will cause injury to the legs and knees. Never.

In the same way, if you glue a molded material that is softer than the foamed polyurethane outer sole after foaming and hardening to the treading part of the lower surface of the shoe cover,
The outer sole of the finished shoe will be easier to bend, and when moving to the next landing while running, no undue force will be applied to the foot.
Never get tired.

The molded product to be embedded in the foamed polyurethane outer sole is usually foamed polyurethane, foamed ethylene-vinyl acetate copolymer, foamed rubber, solid rubber, etc., and its properties vary depending on the location where it is embedded, but for example, If it is inserted into the heel of the outsole, the hardness of the S foam polyurethane outsole is 65.
If the degree is (according to a sponge hardness tester, the same applies hereafter), it is 45 ~
50 degrees, or if it is embedded inside the heel of the outsole, if the hardness of the polyurethane foam outsole is the same < 65 degrees, then 70 ~
A 75 degree angle is used.

EXAMPLE A polyvinyl alcohol fiber outer fabric and a cotton lining fabric are laminated together using a vulcanized adhesive made of natural rubber and styrene-butadiene copolymer rubber, and sewn into a jacket shape. A toecap made of a laminated sheet of vulcanized rubber made of styrene-butadiene copolymer rubber and cotton fabric is attached to this heel, and at the same time, a heel reinforcement piece is sewn with the cotton fabric side facing up. . This shoe cover was hung in a shoe last together with an insole made by wrapping both sides of a foamed polyurethane sheet with cotton fabric, and the outside of the lower heel was placed with a thickness of 4 m, an area of 20 m x 50 m, and a specific gravity of 0.5. A foamed polyurethane molded body having a hardness of 50 degrees was adhered with a polychloroprene adhesive.

On the other hand, a liquid material mainly composed of butylene adipate-based polyester polyol, 1,4-butanediol, and methylene diisocyanate was poured into the cavity of the lower mold at 40°C, and the cavity was filled with Place the shoe last on the bottom mold, cover and allow the foam to harden for 5 minutes, with a specific gravity of 0.6. A white foamed polyurethane outer sole with a hardness of 65 degrees was formed and simultaneously adhered to the lower surface of the shoe to obtain shoes having a foamed polyurethane outer sole.

I wore the shoes with the foamed polyurethane outer sole obtained in this example and did shorts for about 3 months a day, but my heels and knees did not hurt and I did not feel fatigued.

Claims (1)

[Claims] A lower mold in which a liquid foamed polyurethane raw material is injected into the cavity forming the outer sole is combined with a shoe last into which a shoe cover is hung, and heated to foam and harden the liquid foamed polyurethane raw material. In the manufacturing method of shoes having a foamed polyurethane outsole, in which the formed outsole is bonded to the lower surface of the shoe at the same time as the outsole is formed, a foamed polyurethane raw material liquid is injected into the cavity forming the outsole. A molded body having desired properties is inserted into a predetermined position of a closed cavity formed by combining a lower mold and a shoe last with a shoe cover suspended therein, by an appropriate method.
A method for manufacturing shoes having a foamed polyurethane outer sole.