JPS6379602A - Mold for injection molding of shoe sole and production of shoes using the same - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a shoe sole injection molding mold useful for manufacturing shoes by injection molding, and a method of manufacturing shoes using the mold.

<Prior Art> Conventionally, injection molded shoes are manufactured by first suspending a shoe cover into a last mold, and then combining the last mold, left and right sets of side molds, and bottom molds in a conventional manner to form a sole molding cavity. Next, a shoe sole resin material is injected and filled into the sole molding cavity through a runner and a gate in a mold to form a shoe sole, and the shoe sole is then removed from the mold.

In addition, two-layer injection molded shoes (two-color sole shoes) are manufactured by using a mold in which two runners are formed in two layers, upper and lower, and using a second resin material and a second layer of a different material according to the above method. Conventionally, shoe soles are manufactured by injecting and filling a resin material into a sole molding cavity through a runner, and then displacing the mold up and down after the next injection to form a two-layered shoe sole.

<Problems to be Solved by the Invention> By the way, in manufacturing this type of injection molded shoes, from the viewpoint of quality, it is necessary to uniformly fill the sole resin material into the sole molding gap from the tip of the toe to the back of the heel. It is desirable to do so. In particular, in the case of a sponge sole, it is desired that the specific gravity of the sole be constant throughout the sole and that the cell shape be uniform.

However, conventionally, in many cases, a method has been adopted in which the sole resin material is injected into the entire void from the heel of the shoe sole through a runner and a gate communicating with the heel of the void. For this reason, cooling efficiency is poor in the thick heel part near the injection port, which may cause expansion deformation after molding, and secondary foaming after demolding in the case of sponge soles. In the thin-walled toe area, the injected resin material cools relatively easily, and the quality of the material tends to be uneven.
In particular, sponge soles have problems such as the skin layer tends to be thick and the shape of the foam cells increases.

Therefore, the inventor of the present invention conducted intensive research in order to uniformly fill the resin material, and as a result, patent application No. 60-06011? As shown in No. 1, a structure in which a runner is extended from the rear end of the mold to the center of the mold, and the runner and the central part of the sole molding cavity (non-stepping part, treading part, etc.) are communicated by a gate. We are proposing a mold for injection molding of shoe soles.

However, further improvements in this type of injection/filling method have been desired.

In addition, it is generally essential that a shoe sole injection mold has a structure that allows the cured resin in the runner to be easily removed after injection molding, so when designing the mold structure, It is necessary to take this point into consideration.

The present invention has been made in consideration of the above-mentioned circumstances, and its first purpose is to be able to evenly and uniformly fill the sole molding gap with the resin material for soles, and to make the characteristics of each part of the sole uniform. It is an object of the present invention to provide an injection mold for shoe soles, which allows for easy removal of cured resin after molding.

A second object of the present invention is to provide a method for manufacturing shoes with high productivity, such as injection molded shoes with extremely uniform sole parts and sponge sole shoes with uniform sole specific gravity and cell shape. It's about doing.

Means for Solving the Problems> The present invention provides a mold structure that allows resin material for shoe soles to be simultaneously injected from the toe portion or tread portion of the sole molding cavity and from the heel portion of the same cavity. By simultaneously injecting and filling from multiple directions and speeding up the filling, the uniformity of the sole quality is further ensured. In other words, Honmei's shoe sole injection mold consists of a bottom mold, left and right side molds, and a last mold to form the sole molding cavity, and the runner is inserted into both the left and right side molds from the resin injection port on the rear side of the mold. The main gate P is formed so as to extend along the mating surfaces of the runner, branch into left and right branches, and extend along the mating surfaces of the bottom mold and the side mold to the vicinity of the treading part of the sole molding cavity, and furthermore, the main gate P is a branch of the runner. The tip of the runner is provided so that it communicates with the toe part or the tread part of the sole forming gap, and the sub-gate is provided so that the branching part of the runner and the heel part of the sole forming gap communicate with each other. The sign is that it will be.

The mold of the present invention is a split mold similar to that commonly used in the past;
That is, a mold consisting of a last mold, a bottom mold, and a pair of left and right side molds is used. By assembling these molds according to a conventional method, a space corresponding to the sole (sole molding cavity) is formed.

The runner formed in the mold of the present invention preferably extends horizontally from the resin injection port on the rear side of the mold along the mating surfaces of the left and right side molds, and then branches preferably horizontally into left and right bifurcations. The part extends along the mating surface between the left side part of the bottom mold and the left side mold, and along the mating surface between the right part of the bottom mold and the right side mold, up to the vicinity of the treading part of the 9th gap in the sole molding. It is. In the runner of the present invention, the mold portion near the mating portion is formed in the mold portion facing the mating surface, and the mold portion on one side is formed on both sides with the mating surface as a boundary surface. It is more preferable to form the runner on the part of the mold that faces the mating surfaces of the left and right side molds, as this makes it easier to remove residual resin during demolding. This is very preferable since the bottom mold etc. can be smoothly displaced after the second injection molding.

Further, in the mold of the present invention, the branching tip of the runner communicates with the treading part of the sole forming cavity through the main gate, and the overprinting gate connects the branching part of the runner with the heel of the cavity. It consists of communicating.

The main gate and the sub-gate may be a single passage or a plurality of passages, or may be further branched into two or more. In addition, for the main gate, the gate exit (
It is preferable to provide the injection ports in different directions, for example, closer to the toe and closer to the footboard S.

In addition, the shoe manufacturing method of the present invention uses a shoe sole injection mold having the above-described structure, and injects a resin material for a shoe sole from a resin injection port into a shoe sole molding cavity through a runner mold production subgate. It is characterized by manufacturing shoe soles by injection injection and filling.

The resin material used in the present invention is not particularly limited as long as it is a resin composition commonly used in injection molded shoe soles. For example, vinyl chloride resin, thermoplastic rubber, polyurethane, etc. may be used as the resin component. Ru. These resin materials are
Any combination can be used as long as they are compatible and exhibit adhesive properties when heated and melted.

In the case of two-layer soles, it is advantageous to use different types or different resin compositions as the primary and secondary resin materials.

Furthermore, a sponge sole can be manufactured by using a foamable material as a resin material for the sole, and in this case, the weight of the shoe can be reduced. In particular, for shoes with two-layer soles, if a foam material is used as the secondary resin material, the cushioning properties of the shoe sole can be improved, and if a foam material is used as the secondary resin material, the shoe sole can be improved. This allows for weight reduction. As such foamable molding materials, foamable vinyl chloride, foamable urethane, foamable rubber, etc. are used.

Examples of the covering for shoes manufactured by the method of the present invention include woven fabric,
Non-woven fabrics, knitted fabrics, leather, synthetic resin leather, etc. may be used, and the form of the cover to be attached to the last may be either a California cover or a string cover used in a normal last forming method. Therefore, shoes manufactured by the method of the present invention include athletic shoes, jogging shoes, etc.

(Function) In the present invention, the injection ports of the gate are provided at two locations: at the toe portion or stepping portion of the sole molding cavity, and at the heel portion of the cavity. Therefore, the injection-molded special resin material is simultaneously injected from the front and back of the sole molding cavity, and the distance between the injection port and the part of the sole molding cavity that is farthest from the injection port is such that the distance between the injection port and the heel or the foot of the cavity is This is significantly shorter than the conventional case where it was provided at one location on the attachment part.

Therefore, filling of the resin material is completed in an extremely short time.

Therefore, with the present invention, the adverse effects that conventionally occurred due to differences in cooling effect and internal pressure between shoe sole parts, such as uneven sole quality and uneven cell shapes in sponge soles, are completely eliminated. It stops coming out.

Further, in the present invention, the runner can be formed along the mating surfaces of the molds so as to face this surface, that is, so that the runner walls are all exposed on the outer surface of the mold. In this case, the cured resin inside the runner can be easily removed during demolding.

<Example> Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 to 3, the mold of the embodiment includes a bottom mold 1 for forming a molding surface on the upper surface corresponding to the surface of the sole of the shoe, and a pressure mold for forming a molding surface on the inner surface corresponding to the side surface of the sole of the shoe. Right-side side mold 2. a, 2b, and a foot-shaped last mold, and these molds are combined to form the sole molding cavity 4. In addition, in this mold, the runner 6 extends horizontally from the resin injection lower at the rear end of the side mold along the mating surface 10 of the left side mold 2a and the right side mold 2b, and then branches into left and right branches,
The branching parts are the bottom mold 1 and the side mold 2a, respectively.

It is formed so as to extend along the mating surfaces 11, 11 of 2b to the side of the treading part of the sole molding gap 4.

This runner 6 has a mating surface of 10°11 between the molds.
It is formed to face the Also, mating surface 10.1
1-) Runners 16 may be provided on the mold parts on both sides as boundary surfaces.

The mold of the embodiment has a tread portion 12 in the sole molding cavity 4.
At the position, 2 pieces each on the left and right) 8a, 8a, 8
b, 8b so that the tread @ 12 and the branch tip 15 of the runner 6 communicate with each other, and 10,000 is the front (toe side).
The secondary gate 9 is provided at the heel portion 15 of the sole molding cavity 4.
is provided so that the heel portion 1S and the branch portion 14 of the runner 6 communicate with each other. Main gate 8a.

The position of 8b is not limited to the stepping portion 12, but may be within the range of the toe portion of the gap 4 or the stepping portion.

Next, a case will be described in which injection molded shoes are manufactured using the above mold. In advance, four resin filling detection devices (not shown) consisting of a Porro cylinder or the like are installed under the bottom mold 1.

Then, first, hang the yoke 5 into the last mold 3,
Next, the last mold 3, side molds 2a, 2b
A sole molding cavity 4 is formed from the bottom mold 1, and then a resin material for the sole is injected into the runner 6 and the main gate 8a from the resin injection lower.

The void 4 is injected and filled through the auxiliary gate 8b or the auxiliary gate 9. At this time, when the resin filling detection device detects that the filling of the resin material is completed, the injection filling of the resin material is completed. Thereafter, the mold is removed to obtain an injection molded shoe. For the manufacture of sponge-soled shoes, resin materials are used that contain foamable substances.

The shoes manufactured by the method of the example had extremely uniform quality characteristics such as specific gravity, hardness, elasticity, cell shape in the sponge sole, etc. in each part of the sole.

In addition, in the above manufacturing process, after demolding, the runner 6
It was possible to easily remove the cured resin (gate loss) left behind.

(Effects of the Invention) As explained above, the shoe sole injection mold of the present invention has the following features:
By providing main and sub-gates on both the front and rear sides of the sole molding cavity, it is possible to simultaneously fill the resin material from multiple directions.
The resin material can be completely filled into the sole molding cavity in a short time. In addition, the mold of the present invention has a runner formed so as to face each joint of the split mold.
Unnecessary cured resin (gate loss) remaining on the runner after injection molding can be easily removed.

In addition, the shoe manufacturing method of the present invention uses the mold of the present invention to completely and quickly fill the resin material into the molding gap of the shoe sole, which is significantly better than conventional products. To reliably produce injection molded shoes (sponge-in-rule shoes) of the same quality, and to obtain shoe products with no defects or non-uniformity inside the sole. Furthermore, the manufacturing method of the present invention facilitates the removal of unnecessary cured resin, thereby further improving the productivity of shoes compared to the conventional method.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the manufacturing process of shoes using a shoe sole injection mold according to the present invention, Fig. 2 is a sectional view taken along line 1-11M in Fig. FIG. 3 is a diagram showing the runner and gate position of an example mold. In the figure, 1...Bottom mold 2a, 2b...Side mold 3...Last mold 4...Sole molding gap 5...Flip cover 6.16...Runner 7...Resin injection Entrance 8m, 8b...Main gate 9...Sub-gate 10...Matching surface between pass side molds 11...Bottom mold and side mold matching 12...Treading part 13...Heel part 14... Branch part 15... Branch tip part

Claims (2)

[Claims] (1) The bottom mold, the left and right side molds, and the last mold constitute the sole molding cavity, and the runner is extended from the resin injection port on the rear side of the mold along the mating surfaces of the left and right side molds, and then bifurcated into the left and right sides. The main gate is formed so as to branch out and extend along the mating surfaces of the bottom mold and the side mold to near the treading part of the sole molding cavity, and furthermore, a main gate is formed between the branching tip of the runner and the toe of the sole molding cavity. for injection molding of a shoe sole, characterized in that a sub-gate is provided so that a branching part of the runner communicates with a heel part of the sole molding cavity. Mold. (2) The bottom mold, the left and right side molds, and the last mold constitute a sole molding cavity, and the runner is extended from the resin injection port on the rear side of the mold along the mating surfaces of the left and right side molds, and then bifurcated into the left and right sides. The main gate is formed so as to branch out and extend along the mating surfaces of the bottom mold and the side mold to near the treading part of the sole molding cavity, and furthermore, a main gate is formed between the branching tip of the runner and the toe of the sole molding cavity. using a mold for sole injection molding, which is provided so that the part or the tread part communicate with each other, and a sub-gate is provided so that the branch part of the runner and the heel part of the sole molding cavity communicate with each other, A method of manufacturing shoes, comprising injecting and filling the sole molding gap from the resin injection port through the runner and the main and subgates.