JPS5919681B2 - How to make injection molded shoes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing injection molded shoes such as rain boots, and its purpose is to create pleat-like wrinkles in the front part of the laces of the lining fabric during injection molding of the main body of the shoes. The aim is to prevent this from occurring and to provide injection molded shoes that are comfortable to wear and of uniform quality in the finished product.

Conventionally, it is generally well known that a lining fabric made of a stockinette sock is attached to a shoe last, this is set in a mold, and a shoe body molding material is injected into the mold cavity to mold the shoe body. There is.

In this method, the lining fabric was attached to the shoe last using only the stockinette fabric (swelling), and was brought into close contact with the shoe last using only the contractile force of the stockinette fabric.

Therefore, it is difficult to bring the lining fabric into close contact with the shoe last using only the contraction force of the stockinette tissue at the front part of the shoe last, which is formed with a complicated curved surface, and the front part of the last part of the lining fabric has fold-like wrinkles. There were drawbacks that occurred.

Even if these pleat-like wrinkles can be corrected manually when attaching the lining fabric to the last, during injection molding of the main body of the shoe, the complicated curvature of the front part of the shoe last is caused by the molding part of the mold cavity. As the shoe-based molding material flows along the surface in a complicated manner due to the injection pressure, the lining fabric is partially overstretched due to the inherent stretchability of the knitted material in response to the complex flow of the shoe-based molding material. , complex pleat-like wrinkles are formed on the front part of the laces of the lining fabric, and these wrinkles are adhesively fixed by the molded shoe body, and the injection molded shoes molded in this way have The complex pleat-like wrinkles that formed caused poor foot contact and significantly reduced the comfort of wearing the shoes.

In extreme cases, the complex fold-like wrinkles formed on the front part of the laces of the lining fabric may inhibit the fluidity of the shoe-based molding material within the mold cavity during shoe-based molding, and the lining fabric may not be completed. The quality of the injection-molded shoes varied greatly due to the exposed surface of the shoes.

The present invention eliminates these drawbacks, and will be described below with reference to the drawings. At least in the front part 12 of the present invention, the lining fabric 1 made of a stockinette sock 10 knitted with elastic threads 11 is made of stockinette. The tissue and elastic thread 11 are stretched and attached to the shoe last 2, and the lace front part 12 of the lining fabric is brought into close contact with the lace front part 21 of the shoe last by both the contraction force of the stockinette tissue and the elastic yarn 11. After that, the shoe last 2 with the lining fabric attached is set in the mold 4, and the shoe main body molding material is injected into the mold cavity 5 to form the shoe main body 3. That is.

Examples of the elastic yarn 11 knitted into the front part 12 of the lining fabric (sock) used in the present invention include elastic fiber yarns such as rubber yarn and spandex.

These elastic threads 11 may be knitted into the front part 12 of the lining fabric by insert knitting into the stockinette knitting structure, for example, as shown in FIG. If the fabric is knitted into the stockinette knitting structure by a pair, the shrinkage force of the knitting structure in the vertical and horizontal directions can be strengthened, so that the adhesion of the lining fabric 1 to the last 2 can be made even better. .

In the backing fabric 1 used in this invention, the elastic thread 1
1 is made of spandex, and if this is knitted into a stockinette knitted structure by a section as shown in FIG. This makes it possible to perfect the adhesion of the lining fabric 1 to the shoe last 2.

Furthermore, in the lining fabric 1 used in the present invention, if the lower side 13 of the leg adjacent to the front part 12 is knitted more densely than the upper side 14 of the leg, the front part 12 and the leg part Bottom side 14
Since the difference in contraction between the
The lining fabric 1 can be made to adhere uniformly to the shoe last 2 as a whole.

Furthermore, if various patterns 111 are applied to the lining cloth 1 and the shoe main body 3 is molded from a transparent material, the lining cloth 1 will not be partially stretched excessively when the shoe main body 3 is molded. In a large quantity of injection molded shoes molded using lining cloth 111 with the same pattern 111, the patterns 111, 1 are individually molded.
Avoiding irregularities of 11, 111..., patterns 111, 11
It is possible to provide injection molded shoes that can uniformly see through.

In the present invention, examples of the shoe main molding material include vinyl chloride resin, ethylene and vinyl acetate copolymer, liquid polyurethane, thermoplastic rubber, etc. which are commonly used in the manufacture of injection molded shoes.

In this invention, the front part 12 of the lace of the lining fabric is compressed by both the contraction force of the knitted fabric and the contraction force of the elastic thread 11.
1, so even if the front part 21 of the shoe last is formed with a complicated curved surface, the front part 12 of the lining fabric 1 can be brought into close contact with the front part of the shoe last without producing pleat-like wrinkles. 21, and when the shoe main molding material is injected into the mold cavity 5 to mold the shoe main body 3, even if the shoe main molding material flows complicatedly in the front molding part of the mold cavity 5. The front part 12 of the lining fabric 1 is not partially stretched.

Therefore, no fold-like wrinkles are generated in the front part 12 of the lining fabric 1, and the finished injection molded shoe has uniform quality, has a good feel on the foot, and is excellent in comfort.

[Brief explanation of drawings]

The drawings show examples, and FIG. 1 is a sketch of the lining fabric used in the present invention, FIG. It is a tissue diagram of the front part of the lining cloth in Example. FIG. 4 is a sectional view of essential parts showing the manufacturing state of the injection molded shoe according to the present invention. Explanation of symbols, 1... Lining fabric, 10... Socks, 11... Elastic thread, 111... Pattern, 12... Back Front part of the lace of the cloth, 13... Lower side of the leg of the lining fabric, 14... Upper side of the leg of the lining fabric,
2...Shoe last, 21...Front part of shoe last,
3...Shoes main body, 4...Mold,
5...Mold cavity.

Claims (1)

[Claims] 1 At least at the front part 12 of the laces, the lining fabric 1 made of a stockinette sock 10 knitted with elastic threads 11 is attached to the shoe last 2 by stretching the stockinette fabric and the elastic threads 11, and the front part 12 of the lining fabric is stretched. After the part 12 is brought into close contact with the front part 21 of the shoe last by both the contraction force of the stockinette tissue and the contraction force of the elastic thread 11, the last 2 with the lining fabric attached is set in the mold 4,
A method for manufacturing injection molded shoes, which comprises injecting a shoe main body molding material into a mold cavity 5 to mold a shoe main body 3.