JPS5832653Y2 - injection molded shoes - Google Patents

Description

[Detailed description of the invention] The present invention relates to an injection molded shoe that is characterized by improved adhesion to the injection molded material by using a synthetic fiber knitted fabric cover with a characteristic surface texture structure. be.

Injection molded shoes are made by installing a bag-stitched piece of insole fabric sewn onto a foot mold in a foot mold, and then heating and melting a soft polyvinyl chloride resin compound, thermoplastic rubber compound, etc. into the shoe. Manufactured directly in one piece by injection molding as the sole.

Conventionally, vinyl chloride leather, natural leather, knitted fabric, etc. have been used as materials for these coverings, but in order to maintain practical strength in adhesive strength with the injection material, polyurethane resin and polyacrylic resin have been used. It is already well known that surface treatments have been carried out for adhesives, etc.

Both natural fibers and synthetic fibers are used as knitted and woven fabrics for shoes, but consumers prefer shoes made of synthetic fibers because of their good texture, durability, light weight, and stain resistance. The need is very strong.

However, fabrics made of synthetic polyamide fibers (nylon) and polyester fibers, which are commonly used among synthetic fiber fabrics, are difficult to bond due to the high crystallinity of the resin that makes up the fibers. Even if the surface is treated with an adhesive such as polyacrylic resin, sufficient adhesive strength cannot be obtained, and it has been considered impossible to manufacture injection molded shoes using knitted or woven fabrics made of these synthetic fibers for the shoe covers.

As a solution to these difficulties, when using synthetic fiber knitted fabric as a cover, it is possible to use cotton cloth, etc., with adhesive applied in advance to the tape part where the injection material and the cover come into contact.
Side decorations made of other materials and hakama tape sewn on, etc.
We have adopted an indirect bonding method that provides adhesive strength between these textile materials and injection materials.

However, these methods have many problems, such as the use of other cloth materials, the labor involved in sewing, and the loss of aesthetic appearance due to fraying of the seams, and cannot be said to be a satisfactory method.

In addition, we tested using a synthetic rubber adhesive mainly composed of chloroprene, which is often used when making shoes by bonding these synthetic fiber knitted fabrics with synthetic rubber soles or natural rubber soles. Installation, quality degradation due to adhesive protruding outside the tape, decrease in adhesive strength due to softening of synthetic rubber due to transfer of plasticizer contained in the injection material, etc.
Many quality problems were observed, and it was not possible to obtain a satisfactory result.

In view of the above, the inventors of the present invention have conducted extensive research in order to obtain injection molded shoes that have practically sufficient adhesive strength using a shoe cover made only of synthetic fiber knitted fabric, and have developed a special surface for the shoe cover. The present inventors have discovered that all of the above problems can be solved when using a synthetic fiber knitted fabric having a compositional structure, and have come up with the present invention.

That is, the present invention provides an injection molded shoe made of a soft polyvinyl chloride resin compound or a thermoplastic rubber compound as an injection material, in which a protruding loop of dispersed multifilament yarn or a protruding portion whose tip is cut is used as a cover. This invention relates to an injection molded shoe characterized in that it is made of a woven fabric having a textured structure on its surface so that the surface forms an adhesive surface to the injection material.

The present invention will be explained in detail below.

FIG. 1 is a cross-sectional view showing the surface of an example of a knitted fabric used as a cover in the present invention being embedded in an injection molding material.

In the figure, 1 indicates a loop of protrusions of dispersed multifilament yarns supported by ground threads 2, and 3 is an injection material.

The protrusions of the dispersed multifilament yarn in the present invention are generally loops as shown in FIG.
A loop with its tip cut off is also included in the protrusion of the present invention.

This is because both have substantially the same effects.

Examples of textile fabrics having a tissue structure having such loop-like protrusions include pile (for example, French pile) and others.

The fibers constituting the textile fabric of the present invention are not particularly limited, but from a practical standpoint, multifilament yarns of nylon 6, nylon 66, and polyester are preferably used as synthetic fibers.

These yarns may be either untwisted or twisted, but highly twisted yarns in which the single filaments are not dispersed at all when forming protruding loops on the surface are not preferable because the adhesive force with the injection material will not be strong.

The number of single threads, thread thickness, etc. of the multifilament yarn are not particularly limited, and a large number of combinations can be obtained, but the number of single threads is 15 to 72 from the viewpoint of strength and texture as a shoe cover.
The thickness of the thread is preferably from 40 denier to 210 denier.

If the denier is 210 or more, the feel will be hard, but this does not mean that a denier higher than this cannot be used.

In order to increase the anchoring effect with the injection material, for example, 40
16-32 for denier, 15-32 for 210 denier
A good number of single threads is 72.

Incidentally, if the number of single yarns is 32 or more at 40 tensile strength, the strength of the single yarns decreases and the filament density on the ground of the textile fabric increases, resulting in a decrease in the anchoring effect.

Further, if the number of single yarns is 15 or less at 210 denier, the feel of the cloth becomes hard, leading to a decrease in the quality of the cloth.

As the injection material, a soft polyvinyl chloride compound or a thermoplastic rubber compound is used.

Examples of the thermoplastic rubber include polyurethane, butadiene-styrene block copolymer, and the like.

Examples and comparative examples are shown below.

Example 70 When using a jacket consisting of the knitted fabric of FIG. 1 using a 36-filament Nylon 6 multifilament yarn, the flame plasticity was 3.8 kg/cnn for a soft polyvinyl chloride compound. An adhesion force of 3.2 kg/cm width was obtained for the rubber compound.

The adhesive strength was measured using a Schopper tester under the conditions of 180° peeling and a head speed of 200 mm/m·im (the same applies hereinafter).

A 210 d/15 filament nylon 6 cloth yielded adhesion strengths of 3.3 kg/cm width to a soft polyvinyl chloride formulation and 3.2 kg/cm width to a thermoplastic rubber formulation.

Comparative Example Nylon 6 plain weave fabric: 0.2 kg/cm width or less for a soft polyvinyl chloride compound; 0.2 kg/cm width or less for a thermoplastic rubber compound (Weaving with 70 warp yarns per lin by twisting 2 yarns of 16 count, and 24 yarns per 1 inch of weft yarns by twisting 3 yarns of 16 count), weaving with soft polyvinyl chloride compound without applying adhesive. On the other hand, it showed an adhesive strength of 3.0 kg/cm width to a thermoplastic rubber compound of 1.5 kg/cm width.

When the synthetic fiber knitted fabric of the present invention is used as a jacket, the adhesive strength is superior to that when a pile knitted fabric made of spun cotton is used as a jacket, and the adhesive strength does not increase particularly with cotton fabric. It is noteworthy that it exhibits high adhesive strength to flexible polyvinyl chloride formulations.

FIG. 2 is a cross-sectional view showing a plain weave cross-sectional structure and a contact injection material.

In the textile fabric of the present invention, the adhesion area of the dispersed filaments to the injection material is very large, and it is thought that the anchoring effect is increased accordingly.

Although the injection-molded shoes of the present invention use synthetic fiber knitted fabric as the cover, they do not use the indirect adhesive method that was previously required, but instead use a direct adhesive method that uses only the cover. Injection molded shoes having sufficiently high adhesive strength between the injection material and the shoe cover can be obtained regardless of whether the injection molded shoe is used or not.

Furthermore, various types of knitted and woven fabrics that are excellent in feel and feel can be obtained as the woven fabrics used in the present invention, and a wide variety of products that are also suitable for injection molded shoes can be obtained.

The present invention has a great advantage in that a synthetic fiber material can be introduced into the sleeve of an injection molded shoe that has sufficient strength for practical use.

In addition to synthetic fibers, knitted fabrics with similar textures made of filament yarns of recycled fibers or cellulose derivative fibers are of course also effective as the cover.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the bonding surface between the shoe cover and the injection material in the injection molded shoe of the present invention, and FIG. 2 is a cross-sectional view showing the bonding surface between the shoe cover made of plain weave cloth and the injection material. . 1...Protruding loops of dispersed multifilament, 2... Ground yarn, 3... Injection material.

Claims (1)

[Scope of utility model registration request] In injection molded shoes made of a soft polyvinyl chloride resin compound or thermoplastic rubber compound as an injection material, as a cover,
It is characterized in that it is made by using a woven fabric having a textured structure having on its surface protruding loops of dispersed multifilament yarns or protrusions obtained by cutting the tips thereof, such that the surface forms an adhesive surface to the injection material. Injection molded shoes.