JPH04122302A - Production of injection molded shoes - Google Patents

Abstract

PURPOSE:To make it unnecessary to remove burrs after injection molding, by placing a bottom-metal mold on each station of a rotary table and arranging the first injection molding machine at right angles to the bottom-metal mold and also arranging the second injection molding machine at right angles to the bottom-metal mold in the departed position from the first injection molding machine by 2 or 3 stations. CONSTITUTION:A lower sole 5 is left in a sole mold 10 as it is and each mold is relieved. A dummy last 8 is raised upward and exchanged to the last 13 fitted at the opposite side of the dummy last 8. In the last 13, a counter 14 is suspended in the inside and the sole mold 10 is arranged again in the condition that the last 13, the side mold 9, and the lower sole 5 are mounted thereon to define a clearance B 15. Liquid polyurethane resin for the upper sole 4 is injected in the clearance B 15 out of a pouring opening 18 provided at the heel side of the side mold 9 from the second injection molding machine to form the upper sole 4 and form the lower sole 5 and the counter 14 as a unit. In this way, injection molded shoes with a double-layer bottom 6 are completed.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a two-layer shoe sole made of an upper sole made of liquid polyurethane resin and a lower sole made of thermoplastic resin, each integrally molded by injection molding. The present invention relates to a method of manufacturing injection molded shoes with soles.

<Conventional technology> Shoe soles have traditionally been made of urethane resin, which has two or more layers: an upper sole made of urethane resin with good cushioning properties, and a lower sole made of vulcanized rubber or PVC with high anti-slip and abrasion properties. It is widely used because it can take advantage of the advantages of , vulcanized rubber, and PVC to make it highly maneuverable, durable, and lightweight.

The manufacturing method for injection molded shoes with double-layer soles of this type involves press-molding a rubber material, etc. in a separate process to form a lower sole. It is fitted into a mold, and an injection molding machine injects an upper shoe sole molding material such as urethane into the upper shoe sole molding gap between the lower shoe sole and the sole of the shoe, and then the urethane upper shoe sole and vulcanized rubber are injected. Generally, the lower sole and the shoe cover are integrally molded.

Others: Japanese Patent Publication No. 61-28327, Japanese Patent Publication No. 1-139
Some of them are described in Publication No. 002, etc. Tokuko Sho 6]
No. 28327 actively forms a protruding pad around the periphery of the upper sole and the lower sole, and also connects the upper and lower soles together with the pad. This ensures good adhesion at the joint with the sole of the shoe.

In JP-A-1-139002, two turntables are installed, and the lower sole is formed on the first turntable, transferred to the second turntable, treated with an adhesive agent, and transferred to the first turntable again. This is an injection molding method in which the upper sole is injected and a two-layer sole is formed.

<Problems to be Solved by the Invention> In the conventional manufacturing method of injection molded shoes, the manufacturing of the lower sole, which is molded from a rubber material and pretreated, is done by injection molding an upper sole molding material such as polyurethane. Since this is done in a separate process from the main process of completing the shoes, it is necessary to transport the lower soles from the separate process to the main process. Furthermore, if the timing of the main process and another process is different and the lower sole becomes stock, there may be variations in the effectiveness of the puff finishing on the upper surface of the lower sole, adhesive application, etc. performed as pre-treatment for the main process. As a result, there is a problem that poor adhesion between the lower sole and the upper sole occurs during this process, resulting in a decrease in product quality.

The treatment of the upper surface of the lower sole, which is performed as a pretreatment for this process, is as follows:
The main steps are puff finishing performed with a grinder or rotating wire brush, brimer treatment by applying chlorine brimer after the puff finishing, and application of adhesive performed 30 to 60 minutes after the treatment. If this is not done, poor adhesion between the lower and upper soles will occur. Moreover, if the adhesive is not integrally molded with the upper sole in this step as soon as possible (3 to 4 days) after the adhesive is applied, the chemicals forming the lower sole will bleed, reducing the effectiveness of the adhesive. Further, during storage for 3 to 4 days, exposure to direct sunlight may cause deterioration of the adhesive, or the adhesion of flakes may cause poor adhesion.

The method of molding the pads is to ensure sufficient adhesion, but forming the pads of equal thickness protrudingly on the bottom and sides of the sole requires a knife or knife in the finishing process after injection molding. Paris must be removed with an electric trowel.

The method of installing two turntables requires a complicated device and requires frequent transfer and gluing of the lower sole.

<Means for solving the problem> A bottom molding mold is placed on each station of a rotary table equipped with a large number of stations, a first injection molding machine is arranged perpendicularly to the bottom molding mold, and the first injection molding machine is placed at a right angle to the bottom molding mold. A second injection molding machine is placed perpendicular to the bottom mold at a location two to three stations apart from the injection molding machine.

)<Example> Examples of the present invention will be described below.

A dummy last (8
), a last αJ, a side mold (9), and a sole mold arj, and a bottom molding die that can be freely assembled and disassembled is placed thereon.

A first injection molding machine (3) for injecting a thermoplastic resin at right angles to the bottom molding die is arranged, and the first injection molding machine (3) is connected to station (+9) 2 of the rotary table (7).
A second injection molding machine (2) that injects liquid polyurethane resin is placed at right angles to the bottom mold (a) at positions separated by ~3 pieces. An injection molding apparatus (1) with a two-layer bottom (6) having the above configuration (see FIG. 1).

A dummy last (8) and side mold (9) are made by placing a specially formulated thermoplastic polyurethane resin that does not require adhesive treatment on a rotary table (7) from the first injection molding machine (3) that injects thermoplastic resin first. , mold the sole mold αω to form a void Aαυ for molding the lower sole (5), inject into the void Aαυ from the injection port AQη provided on the heel side of the side mold (9), and mold the sole mold QQ). The lower sole (5) is formed through the spool runner (see Figure 2).

The lower sole (5) is a solid sole.

Next, each mold is released, leaving the lower sole (5) as it is in the sole mold α. The dummy last (8) rotates upward and replaces the last α3 installed on the opposite side of the dummy last (8). Last α31:l;! Fake Q
4) is suspended, and the sole mold α is placed with the last αJ, side mold (9) and lower sole (5) on it.
0) is molded again to form a cavity B (F9). Liquid polyurethane resin for the upper sole (4) is applied to the cavity B (IS) from the second injection molding machine (2) to the heel of the side mold (9). Inject the upper shoe sole (4) from the injection port BQ8 provided on the side.
), the lower sole (5) and the shoe cover (04) are integrally molded, and an injection molded shoe having a two-layer sole (6) is completed (see FIG. 3).

The sole of the upper part of the shoe (4) has a spongy shape with good cushioning properties.
, the joint Oe with the lower sole (5) has sufficient adhesive strength, and the color of the sole can be combined in various ways depending on the design and color of the shoe cover 04. Further, the material of the lower sole (5) is not limited to thermoplastic polyurethane.

<Effects> According to the present invention, there is no need to make the pads protrude from the upper and lower soles (the mold production is also simplified accordingly, and the finishing after injection molding by the method of the present invention eliminates the need for pads to protrude from the upper and lower soles). No need to delete.

There is no need to install two turntables, transfer the lower soles, or process adhesives. In addition, since the lower sole and upper sole are integrally molded at the same time, there is no need to manufacture the lower sole in a separate process, and there is no need to use adhesives. There is no need to worry about the decrease.

It eliminates the trouble of transporting the lower soles and is economical.
Additionally, since it is a direct sole method in which the lower sole and upper sole are integrally molded at the same time on the same rotary table, a high quality product with good adhesion can be manufactured.

[Brief explanation of drawings]

Figure 1 shows the layout of the machine. FIG. 2 is a cutaway sectional view of the lower sole. FIG. 3 is a cutaway sectional view of the upper sole. (1) Injection molding device (2) Second injection molding machine (3
) 1st injection molding machine (4) Upper shoe sole (5) Lower shoe sole (6) Double layer sole (7) Rotary table
(8) Dummy last (9) Side mold (10
) Sole mold (11) Gap A (1
2) Spool runner (13) Last (15) Gap B (17) Inlet A (19) Station (14) Cover (16) Joint (18) Inlet B (20) Bottom mold.

Claims (1)

[Claims] A first injection molding machine (20) is placed on each station (19) of a rotary table (7) equipped with a large number of stations (19) each having a mold clamping mechanism, and a thermoplastic resin is injected. After molding the lower sole (5) by injecting thermoplastic resin into the sole molding die (20) according to step 3), the rotary table (7) is inserted into the sole molding die (20).
A second injection molding machine (2) injects liquid polyurethane resin.
), and liquid polyurethane resin is injected from the second injection molding machine (2) to form the upper sole (4).Direct sole injection molding featuring a different two-layer sole (6) How to make shoes.