JPH0737085B2 - Injection molding method for boots - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding method for boots.

[0002]

2. Description of the Related Art Conventionally, a boots-based molding material is injection-filled into a boots-based molding space formed by an outer mold, an inner mold, and a primary bottom mold, through an injection hole provided behind a step portion of the primary bottom mold. After molding the boots main body, the primary sole mold is replaced with the secondary bottom mold, and the shoe sole molding material is injection-filled into the shoe sole molding void formed by the bottom portion of the boots main body and the secondary sole mold. , A method of welding and molding the shoe sole on the bottom of the boots is disclosed in Japanese Patent Publication No. 43-103.
Proposed in No. 78. However, in order to reduce the weight of boots, the boot main part is formed to be remarkably thinner than the bottom of the boots, and the upper surface of the toe is formed with a complicated curved surface, as shown in FIGS. 4 and 5. The boots main molding material is filled into the toe top molding void d at the final stage, and the boots molding material is filled into the toe top molding void d at the tip a ₁ of the bottom molding void a.
Since the flow of the molding material from the right and left side edges a ₂ of the bottom molding space a and the molding space c of the bottom portion is performed rigorously, the boots main molding material filled in the toe top molding space d is Flow marks and sink marks are formed on the upper surface of the toe part of the molded boots body due to air bubbles being mixed inside, insufficient filling due to lowering of molding material temperature and injection pressure, and loss of volume balance. It was formed and the appearance was remarkably deteriorated.

As a remedy for this problem, a bottom mold and an upper mold (dummy mold) provided with a flow groove forming projection from the step portion to the toe portion are provided with a flow groove on the upper surface from the step portion to the toe portion. After injection molding, replace the dummy mold with the outer mold and the inner mold (last) while molding and holding the shoe sole in the sole mold, and form the boots main molding void on the upper surface of the sole, and mold the boots main molding in this void. A method has also been proposed in which the material is injected and introduced, and the main body of the boots is weld-molded on the upper surface of the shoe sole. According to this method, it is possible to mold the boots main body while promoting the filling of the boots main part molding material into the molding gaps on the top of the toes through the flow grooves formed on the upper surface of the shoe sole when molding the boots main part. Although it is possible to avoid the inclusion of air bubbles and the formation of flow marks and sink marks, when the dummy mold is released from the bottom mold after the shoe sole is molded, the flow groove molding projection is formed on the flow groove formed on the upper surface of the shoe sole. Since it is biting, the shoe sole adheres to the dummy mold and is released from the bottom mold, so it is necessary to reset it to the sole mold, and the work is complicated. When the boots-based molding material is different from the one in the boots due to the poor adhesion between the sole and the bottom mold to reset, the boots-based molding material sticks out to the side of the shoe sole during the boots-based molding, and the boots and the boots mainly The boundary between and is unclear, which reduces the appearance. There is a point.

[0004]

SUMMARY OF THE INVENTION The present invention uses a simple method to introduce air bubbles into the upper surface of the toes of mainly boots,
It is an object of the present invention to provide boots in which flow marks and sink marks are not generated and the boundary between the boots mainly and the sole different from the boots is clear.

[0005]

The present invention will now be described with reference to the drawings showing the embodiment of the present invention.
, The inner mold 12, and the injection hole 13 provided at the rear of the step portion.
With the primary bottom mold 13 in which a band-shaped flow groove 131 is formed on the upper surface from the 0th part to the toe part, and branch grooves 1311 and 1311 ... are further formed from this band-shaped flow groove 131 toward the left and right from the stepped part to the toe part. The boots main body 3 is formed by injecting and filling the boots main molding material 2 into the formed boots main molding void 2.
After molding, the primary sole mold 13 is replaced with the secondary sole mold 14, and the shoe sole molding gap 4 formed by the bottom portion 31 and the secondary sole mold 14 mainly composed of the boots is different from the boots 3 mainly. The gist of the invention is an injection molding method for boots, characterized in that the sole 5 is injection-filled and the shoe sole 5 is welded to the sole 31 mainly composed of the boots.

In the present invention, the boots-based molding void 2 also serves as a flow path for the boots-based molding material.
1. The upper surface of the toe part has a molding gap 22, a crevice molding space 23, and a body molding space 24. The upper surface of the primary bottom mold 13 has a belt-like distribution from the injection hole 130 provided at the rear of the stepping part to the toe part. The groove 131 extends from the belt-shaped flow groove 131 toward the left and right sides from the stepped part to the toe part to form the branch groove 131.
, 1311 ... are provided, and the flow path from the toe portion and the side portion to the toe portion upper surface forming void 22 direction is expanded in the bottom portion forming void 21 by the band-shaped circulation groove 131 and the branch grooves 1311, 1311.

In the boots main molding void 2 thus constructed, vinyl chloride such as vinyl chloride resin, copolymer resin of vinyl chloride and vinyl acetate, copolymer resin of vinyl chloride and ethylene, etc. is prepared by a conventional method. If a conventional rubber boots molding material such as a base synthetic resin, a copolymer resin of ethylene and vinyl acetate, or a thermoplastic rubber is injected through the injection hole 130, the molten rubber boots molding material is first filled in the bottom molding void 21. The boots main molding material filled in the bottom molding void 211 in front of the injection hole 130 is expanded by the flow groove 131 by the injection pressure of the boots main molding material continuously injected from the injection hole 130. Using the bottom molding void 211 as a flow path, the toe top molding void 22 and the toe molding void 23
Are sequentially extruded and press-fitted. On the other hand, the boots-shaped molding material filled in the bottom molding space 212 and the tail molding space 23 behind the injection hole 130 is relatively flat and has a relatively flat surface below the body molding space 24 while maintaining balance by injection pressure.
The boots 41 are sequentially pressed into the upper portion 242 to complete the injection filling of the boots-based molding material into the boots-based molding void 2.

After molding the boots main body 3 in this way,
The primary sole mold 13 is replaced with a secondary sole mold 14 to form a shoe sole molding gap 4 by the bottom portion 31 mainly composed of boots and the secondary sole mold 14, and the shoe sole molding gap 4 is different in color from the boots main body 3. Injecting a usual shoe sole molding material such as vinyl chloride synthetic resin, copolymer resin of ethylene and vinyl acetate, thermoplastic rubber, etc., and welding the sole 5 of a different color to the sole 31 mainly composed of boots. It is what is molded.

[0009]

As described above, according to the present invention, when the boots-based molding material is injection-filled into the boots-based molding void 2, the belt-shaped flow groove 131 and the branch groove 1311, which are formed on the upper surface of the primary bottom mold 13, are provided. 1311 ... facilitates the filling of the toe upper surface forming void 22 from the toe portion and the side portion in the bottom forming void 21 at the initial stage of the boots main molding 3 and can be completed. There are no bubbles on the top surface and no flow marks or sink marks are formed on this part. Further, after the boots main body is molded, the boots main body 3 is held in close contact with the outer mold 11 and the inner mold (last) 12 in the state of being closely molded to maintain the primary bottom mold 13 and the secondary bottom mold 14.
Since the shoe sole molding material does not stick out to the side surface of the boots main body 3 at the time of molding the sole, the boots having a clear boundary between the boots main body 3 and the sole 5 can be injection-molded.

[Brief description of drawings]

FIG. 1 (A) is a cross-sectional view of essential parts showing a state in which boots are mainly molded according to the present invention. (B) It is an essential part sectional view showing a shoe sole molding state in the present invention.

FIG. 2 is a plan view of a primary bottom mold used in the present invention.

FIG. 3 is a sectional view taken along line XX of FIG.

FIG. 4 is a cross-sectional view of essential parts showing a state in which boots are mainly molded in a conventional example.

5 is a cross-sectional view taken along line YY of FIG.

[Explanation of symbols]

11. Outsole 12. Inner mold 13. Primary bottom type 130 ... Injection hole 131 ... Strip-shaped flow groove 1311 ... Branch groove 132 ... Toe portion long end 14. Secondary bottom type 2. Boots main molding void 21 ... bottom molding void 211 ... bottom molding void in front of the injection hole 212 ... bottom molding void behind the injection hole 22 ... toe upper face molding void 23 ... crevice molding void 24 ... trunk molding void 241 ... Lower part 242 ... Upper part 3. Boots mainly 31 ... bottom 4. Molding space for shoe soles 5. Shoe sole

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // B29C 45/14 8823-4F 45/16 8823-4F

Claims (1)

[Claims] 1. An outer mold 11, an inner mold 12, and a band-shaped flow groove 131 formed on the upper surface from an injection hole 130 provided in the rear of the stepped part to a toe part, and the band-shaped flow groove 131 is further stepped. A boots-based molding material is injection-filled into a boots-based molding space 2 formed by a primary bottom mold 13 having branch grooves 1311 and 1311 ... After that, the primary sole mold 13 is replaced with the secondary sole mold 14, and the sole molding gap 4 formed by the sole 31 mainly composed of the boots and the secondary sole mold 14 is molded into a sole different in color from the boots main body 3. An injection molding method for boots, characterized in that the material is injection-filled and the shoe sole 5 is welded to the sole 31 mainly composed of boots.