JPS6312601B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing antistatic injection molded shoes.

With the development of petrochemistry, highly insulating synthetic resins,
Synthetic fibers have become widespread,
As a result, accidents due to static electricity charging tend to occur frequently.

The same applies to the human body, and therefore antistatic shoes with conductivity are used.

Generally, when attempting to manufacture a large quantity of shoes at a relatively low cost, injection molding is generally used, and the same can be said of antistatic shoes as described above.

Conventionally, a few methods have been proposed for obtaining antistatic shoes by injection molding, and shoes obtained by these methods are actually used.

For example, a layer of conductive printing ink is applied to the side of an insole fabric that does not contact the sole of the foot with conductive fibers exposed on both sides, covering only the exposed conductive fibers. Anti-static material is sewn to the lower periphery, hung on a shoe last, combined with a sole mold having a hole in the sole, and injected conductive sole material into the hole. Injection molded shoes have been proposed.

Shoes obtained using this method use highly conductive parts such as the insole fabric, conductive print ink layer, and conductive sole material, so they can absorb the electricity necessary for antistatic shoes. Although the resistance can be easily adjusted to fall within the range of 10 ⁵ to 10 ⁸ ohms, the conductive printing ink layer is applied only to specific areas of the insole fabric that do not contact the sole of the foot, i.e. the exposed surface of the conductive fibers. The coating process is time-consuming, and since the surface that contacts the sole of the foot is in contact with the conductive part only through exposed conductive fibers, the insole fabric is woven with a large amount of conductive fibers. However, it has the drawback of being relatively expensive both from a process standpoint and from a material standpoint.

The purpose of the present invention is to eliminate the drawbacks of the conventional antistatic injection molded shoes as described above. , Apply conductive glue of almost the same color as the insole fabric to the surface in contact with the sole of the foot so that it oozes out,
It is sewn to the lower periphery of the shoelace, and the shoelace is hung on the shoe last.
This was achieved by manufacturing an injection molded shoe by combining a sole mold having a sole cavity and injecting a conductive sole material into the cavity.

The above-mentioned insole cloth used in the present invention is a single-layered one coated with conductive glue of approximately the same color as the insole cloth on the side that does not contact the sole of the foot, and A plurality of fabrics coated with conductive glue of approximately the same color as the insole fabric and then laminated with coarse fabric such as sackcloth, cheesecloth, etc. that allows the conductive shoe sole material to pass through sufficiently during injection molding, or both. This includes: or,
The conductive glue may be non-black and have an electrical resistance within the range of 10 ⁵ to ^{10 8} ohms required for shoe soles, and is usually made of polyurethane, polyvinyl chloride, vinyl chloride-acetic acid. Vinyl copolymers, mixtures thereof, and the like are used, and antistatic agents such as surfactants, quaternary ammonium salts, and polyhydric alcohol derivatives are added. Further, as the insole cloth, a normal fabric not mixed with conductive fibers is used, but there is no problem in using a cloth mixed with some conductive fibers as long as the price does not become high.

In the present invention, the conductive glue applied to the surface not in contact with the sole of the foot exudes from the surface of the insole fabric that comes into contact with the sole of the foot, so the insole fabric itself has almost no conductivity. However, the conductive glue that oozes out ensures the conductivity necessary for the sole of the shoe. In this case, the inner sole fabric
As long as conductive fibers are mixed within a range that does not increase the price, it is possible to further impart conductivity to the sole without impeding the object of the present invention. Furthermore, it is not necessary to selectively apply conductive glue to the surface that does not contact the sole of the foot, as was done in the manufacturing process of the conventional conductive injection molded shoes, only to the exposed parts of the conductive fibers. Since it is sufficient to uniformly coat the entire surface, no effort is required and the process is simple. Furthermore, the conductive glue that oozes out from the surface in contact with the sole of the foot can be freely selected from a non-black color to match the insole fabric.
It is possible to avoid the phenomenon of contaminating the wearer's socks, which sometimes occurred when wearing conventionally proposed shoes.

Example Mirable urethane containing conductive glue (polyester base, =
12000) 60 parts by weight Vinyl chloride-vinyl acetate copolymer 40 〃 Calcium carbonate 100 〃 Plasticizer DBP 35 〃 Quaternary ammonium salt 10 〃 Titanium oxide 2 〃 The above mixture was kneaded using a roll machine, and the kneaded product was solidified into methyl ethyl ketone. A glue was obtained by dissolving the mixture to a concentration of 45%.

This glue was applied uniformly to the entire surface of a white cotton insole fabric mixed with 0.1% carbon fiber that did not contact the sole of the foot, and a piece of cotton cheesecloth was placed over the coated surface and allowed to dry. At this time, glue was oozing out evenly in the form of dots on the surface of the insole fabric that was in contact with the sole of the foot. This was sewn to the lower periphery of a double-woven cotton shoe cover to obtain a bag-stitched shoe cover, which was hung on a shoe last.

This shoe last was combined with a sole mold heated at 180° C., and the following conductive sole material compound was injected into the sealed cavity of the sole mold for 4 minutes, and then taken out and cooled to obtain a shoe.

Polyvinyl chloride mixed with conductive shoe sole agent (=1000) 100 parts by weight Plasticizer DBP 40 〃 Plasticizer DOP 50 〃 Calcium carbonate 40 〃 Quaternary ammonium salt 2 〃 As mentioned above, in the manufacturing method according to this example Since the conductive glue only needs to be applied uniformly over the entire surface of the white insole fabric that does not touch the sole of the foot, there is no need for any effort, and the white insole fabric contains a very small amount of carbon fiber. Since it is a mixed weave, it has little effect on the price, and the electrical resistance as a shoe sole is ¹⁰⁷ ohms (according to JIS T8103 2nd test method), so it has sufficient performance as an antistatic shoe. Therefore, even when wearing white socks for a long time, there was no contamination.

Claims (1)

[Claims] 1 Apply conductive glue of approximately the same color as the insole fabric to the side that does not contact the sole of the foot so that it oozes out to the side that contacts the sole of the foot, and sew it to the lower periphery of the lace. 1. A method for manufacturing a conductive-preventing injection molded shoe, which comprises suspending the cover over a shoe last, combining it with a sole having a sole cavity, and injecting a conductive sole material into the cavity.