JPH04279101A - Making of outsole having slip-preventing piece - Google Patents

Abstract

PURPOSE:To obtain an urethane foam-made outsole wherein, from the slip- preventing piece in contact with the ground, no thin layer is produced, and the external appearance is not deteriorated. CONSTITUTION:A solid slip-preventing piece made of thermoplastic polyurethane elastomer is formed at the definite place of a female mold, and is placed in that state, following which liquid polyurethane is poured on the upper surface thereof by an ordinary process. After that, it is allowed to foam in a definite shape, to be hardened, and thus a desired outsole can be obtained.

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 outsole having an anti-slip piece that does not require a finishing process or the like.

0002

BACKGROUND OF THE INVENTION Foamed polyurethane shoe outsoles are widely used because they are lightweight and comfortable to wear. However, since hard cast polyurethane with a rough surface is used,
It lacked grip and therefore had poor anti-slip properties, and since it was a foam, it also lacked abrasion resistance.

[0003] Conventionally, in an attempt to eliminate the drawbacks of such foamed shoe outsoles obtained from cast polyurethane, vulcanized rubber pieces have been fitted to the treading part and/or heel part of the contact surface of the shoe outsole. The method was adopted. To obtain the above-mentioned shoe outsole, the rubber pieces are subjected to separate processes in advance, including weighing raw rubber, fillers, rubber chemicals, etc., rough kneading, rolling, and molding at approximately 160°C for 6 minutes. The rubber obtained in this way is manufactured by sequentially passing through each process such as sulfur, deburring, primer treatment at about 70°C for 5 minutes, and solvent glue application at about 70°C for 5 minutes. This was obtained by temporarily attaching the piece to a predetermined location in the cavity for forming the outsole of the lower mold, and then injecting and filling it with a cast polyurethane liquid that could be combined with the upper mold to form a foam, and then hardening.

0004

[Problems to be Solved by the Invention] However, the above-mentioned conventional shoe outsole has the drawback of increasing manufacturing costs because a complicated process is required to obtain the anti-slip piece that fits into the ground contact surface. Was. Moreover, since the process includes multiple heat treatment steps, primer treatment steps, solvent glue application steps, etc., the anti-slip piece, that is, the rubber piece, shrinks greatly.
The shrinkage of the foam also varies from piece to piece, making it impossible to fit tightly into the hole for forming the anti-slip piece in the lower mold.Therefore, the foam was inserted into the hole for forming the outer bottom formed by the lower mold and the upper mold. When the moldable polyurethane liquid is injected and filled, it sinks into the underside of the anti-slip piece and after the outsole of the shoe is completed, it takes a lot of effort to remove the thin film attached to the underside of the anti-slip piece. SUMMARY OF THE INVENTION The object of the present invention is to solve all the drawbacks of the conventional method of manufacturing a shoe outsole having an anti-slip piece.

[0005]

[Means for Solving the Problems] The present invention forms a cavity for forming an anti-slip piece using a lower mold and a dummy mold, and injects and fills the cavity with a thermoplastic polyurethane elastomer capable of forming a solid body. After curing, the dummy mold is removed, the lower mold and the upper mold are combined, and the cavity for forming the outer sole created at this time is injected and filled with a cast polyurethane liquid capable of forming a foam, and then cured. The gist of this paper is a method of manufacturing a shoe outsole having a characteristic anti-slip property.

[0006] Thermoplastic polyurethanes that can form solid bodies have linear elastomers, and cast polyurethanes that can form foams have crosslinked elastomers. This is a segmented block polymer consisting of hard blocks and soft blocks. The rigid blocks are also called domain polymers because they are held together by hydrogen bonds within the domains. The hard block segments consist of polyurethane derived from methylene diisocyanate and short chain glycols such as ethylene glycol, butanediol, or hexanediol. The soft blocks consist of macroglycols with higher molecular weights (1000 or more). The most commonly used macroglycols are butanediol adipate, polytetramethylene glycol, polyoxypropylene glycol, and polycaproate. Cast-molded polyurethane often forms closed cells and becomes a foam by mixing water. In the present invention, the stiffness of the thermoplastic polyurethane solid body is preferably 65 to 70A (according to JIS K6301, cuttlefish test).

[0007]

[Function] In the present invention, the anti-slip piece is obtained by a cavity formed by a part of the combination mold forming the entire outsole, that is, the lower mold and the dummy mold, and the next step is to remove the dummy mold. Since the outer sole of the shoe is formed in a continuous process using the lower mold and upper mold after the molding, there is no need for many heat treatment processes and bonding processes as in the case of rubber pieces, and therefore there is no shrinkage of the anti-slip piece. Moreover, it remains fitted into the lower mold cavity until the final process.
The material that forms the outer sole of the shoe becomes a thin film that does not sink into the bottom surface.

[0008]

[Example] Thermoplastic polyurethane (manufactured by Kuraray Co., Ltd.) heated and melted at 200°C was placed in the cavity (formed in the stepping part and heel part) obtained by combining the lower mold and the dummy mold. Injection filled with Kuramiron U6770 Katasa 70A) 7
Cool to 0°C, remove the dummy mold, prime the top surface of the resulting anti-slip piece with a moisture-curing polyurethane adhesive, and combine with the lower mold to form a cavity.The mold is heated and melted at 40°C. The polyurethane liquid was injected and filled, and after 5 to 7 minutes, the upper mold was removed to obtain the outsole of the present invention. Natural rubber 70 parts by weight Polybutadiene rubber 30 Vulcanization accelerator M 0.5 Vulcanization accelerator DM 1.5 Vulcanization accelerator TS 0.1 White carbon 40 Spindle oil 5 Zinc white
5 The above mixture was kneaded, aged at room temperature for 1 day, and rolled to obtain an anti-slip piece of the same size as above at 170° C. for 5 minutes. Hereinafter, a shoe outer sole was obtained using the same materials and conditions as above, and this was used as a control example. The physical property values of both were as follows.
This invention Shrinkage rate (%) of control example anti-slip piece 0
3-4 anti-slip piece clasp (JIS
A) 65-70 65 Appearance of outer sole of shoes Good
Good Thin film adheres to the sides

0009
]

[Effect] It was possible to obtain a shoe outer sole having an anti-slip piece on a predetermined contact surface through a simple process and without requiring any finishing process such as removing extrusion.

Claims (1)

[Claims] 1. A cavity for forming an anti-slip piece is formed by a lower mold and a dummy mold, and after the cavity is injected and filled with a thermoplastic polyurethane elastomer capable of forming a solid body, the dummy mold is removed, and the dummy mold is removed. A shoe outsole having an anti-slip piece characterized in that a lower mold and an upper mold are combined, and a cast polyurethane liquid capable of forming a foam is injected and cured into the cavity for forming the outer sole created at this time. manufacturing method.