JP2002144366A - Foamed molding and article using foamed molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a footwear sole material which is lightweight and shows such manufacturing advantages that the manufacturing manhour can be cut, no burr removing operation is required and the wasteful consumption of a material resin can be eliminated and a manufacturing method and a manufacturing device therefor. SOLUTION: The manufacturing method for the article using foamed moldings comprises the step to knead and adjust a resin initimate mixture obtained by adding 2-4 pts.wt. of dicumyl peroxide and 4.5-8 pts.wt. of azodicarbonamide to 100 pts.wt. of a resin composed mainly of EVA, e.g. 75-85 wt.% of EVA and 15-25 wt.% of an ethylene propylene rubber(EPR), the step to supply the resin intimate mixture to an injection molding machine 10, melt and knead the resin intimate mixture at a decomposition temperature or lower of a foaming agent, inject the molten resin intimate mixture into a footwear sole material molding die 11 heated at the decomposition temperature or higher of the foaming agent and mold the mixture and release the moldings from the die 11 to expand them 1.3-1.8 times as much and the step to remove the internal stress.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight and highly productive foam molded article which eliminates the need for deburring, eliminates waste of material, and relates to a method and an apparatus for producing the same.

[0002]

2. Description of the Related Art Foamed polyurethane has been widely used as a foamed molded product, for example, a footwear sole material, and this footwear sole material has a certain effect in weight reduction, but the number of manufacturing steps is reduced. Not enough in terms of perspective.

[0003] In view of the above, the development of a foamed molded article such as a footwear sole material that is lightweight and has good productivity has been desired, and Japanese Patent Application No. 2-10720 (Japanese Patent Publication No. 4-708) has responded to the expectation.
No. 88) has proposed a "method of forming foamed shoe soles".

[0004] The above proposal is based on a mixed polymer obtained by mixing 5 to 20 parts by weight of chlorosulfonated polyethylene with 100 parts by weight of a copolymer with ethylene vinyl acetate (hereinafter referred to simply as EVA). A cross-linked foaming shoe sole molding material to which a cross-linking agent and a foaming agent are added is introduced into the mold cavity, which is pressurized and heated to cross-link the plastic sole, and then the mold cavity is opened to form the plastic sole. Is a foaming shoe sole having a C hardness of 40 to 55 by foaming 1.3 to 1.8 times.

[0005]

According to the above prior art, a reduction in weight can be expected in molding and foaming a foamed resin admixture mainly composed of EVA containing a crosslinking agent and a foaming agent. Introducing the shoe sole molding material into the mold cavity "is required, and this process will be described more specifically.
The above EVA-based resin admixture is obtained by a kneading roll, formed into a plate shape by a calender roll, cut into a predetermined size, loaded into a molding die, and crosslinked under pressure and heat to form the molded product. Is released from the mold to obtain a foamed shoe sole.

In the above prior art, a step of making the kneaded resin mixture into a plate shape with a calender roll is required. If the amount of the plate-like resin mixture to be charged into the mold is smaller than the inner volume of the cavity, Due to molding failure, a slightly larger amount of resin mixture is loaded into the mold, which causes burrs on the molded product and necessitates deburring work, which is a waste of material and an obstacle to improving productivity. I have.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a foam molded article which is lightweight, does not require deburring work, has good productivity, has no waste of materials used, and provides a method and an apparatus for producing the same. .

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a resin mainly composed of EVA, for example, EV.
A to 75 to 85% by weight of ethylene propylene rubber (E
A resin mixture obtained by adding a crosslinking agent and a foaming agent to a resin having a PR of 15 to 25% by weight is injection-molded into a mold by an injection molding machine, and the molded product is opened from the mold to 1.3. ~ 1.8
Foamed and expanded twice, 75 to 85% by weight of ethylene vinyl acetate copolymer and 15 to 25% of ethylene propyne rubber.
A resin mixture in which a crosslinking agent and a foaming agent are added to a mixed resin with a weight%, and a kneading adjustment, and the resin mixture is supplied to an injection molding machine and melt-kneaded at a decomposition temperature or lower of the foaming agent,
A step of injecting and molding the melt-kneaded resin mixture into a mold heated to a temperature not lower than the decomposition temperature of the foaming agent, a step of releasing the molded article from the mold to expand and expand, and a step of removing internal stress. In the above method for manufacturing a sole material for footwear, the injection molding machine and a plurality of frames equipped with a heating / pressing mold are relatively movable and can be sequentially coupled. .

According to the present invention having the above structure, E
The resin mixture mainly composed of VA is foam-molded by injection molding in the above-described procedure, so that a lightweight foam-molded product can be obtained while reducing the number of manufacturing steps. Can be eliminated, the uneven distribution of the material resin can be eliminated, and the quality of the foam molded article can be greatly improved.

The above-mentioned EVA has a vinyl acetate content of 10 to 10.
30%, preferably 20 to 25% is employed.

In the ratio between EVA and EPDM, EVA
If the content is too large, the abrasion resistance is reduced, and the flexibility and oil resistance of the EVA are reduced.

When the amount of the crosslinking agent is less than the above amount, the desired hardness and abrasion resistance cannot be obtained, and the crosslinking agent tends to be deformed. When the amount exceeds the above amount, the crosslinking agent becomes hard and the flexibility decreases. The feeling of use is poor, and the comfort of the footwear is reduced, which is not preferable from the viewpoint of economy.

When the amount of the foaming agent is less than the above-mentioned amount, desired foaming cannot be obtained, the object of weight reduction cannot be achieved, and flexibility cannot be obtained. When the amount is more than the above-mentioned amount, the foam is excessively formed and the wear resistance and the durability are impaired.

[0014]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 illustrates the relationship between a mold 11 and a resin mixture injection orifice 12 of an injection molding machine. FIG. 1A shows a state in which an upper mold 11a and a lower mold 11b are pressed by a hot plate 13; (b) shows a state where the resin mixture injection orifice (12) of the injection molding machine (10) is brought into contact with the mold (11), and (c) pressurizes and heats the molded article (14) for a predetermined time.
Is opened from the mold 11 and expanded.

FIG. 2 shows a state in which the injection molding machine 10 and the mold 11 are connected to each other. A ram 16 is suspended from a frame 15 and a yoke Y is attached to a lower end of a cylinder 17. Since it has a structure in which the operating yoke Y2 is attached to the upper end of the column C, the orifice 12b of the mold 11
The level of the resin mixture injection orifice 12 (see FIG. 1) of the injection molding machine 10 (see FIG. 1) coincides with the level of the orifice 12 (see FIG. 1) regardless of the elevation of the upper die.

Further, as shown in FIG. 3, all the other molds 11 are in agreement with each other. In this state, when the injection of the resin mixture is completed, the injection molding on the track 18 (see FIG. 2) is performed. The machine 10 sequentially includes a hot plate 13, a mold 11, and a ram 16,
The resin mixture can be injected by moving sequentially to the frame 15 on which the cylinder 17 is mounted.

Therefore, after the resin mixture shown in Table 2 is injected, the resin mixture can be injected one after another without waiting for the foaming time. In the above embodiment, the injection molding machine 10 is moved. However, the injection molding machine 10 is fixed, and the hot plate 13, the mold 11, the ram 16, and the frame 15 on which the cylinder 17 is mounted are put on the track. It can also be moved. Further, although the frames 15 are arranged side by side in the drawing, the effect of reducing the number of man-hours can be further exerted if the frames 15 are arranged in a circular orbit so as to move around the frame.

[0018]

EXAMPLES Table 1 shows the performance of the injection molding machine used in this example and the temperature conditions of the kneading cylinder.

[0019]

[Table 1]

Next, a 6 mmφ × 4 mm pellet-shaped resin mixture having the composition shown in Table 2 was supplied to the above-mentioned injection molding apparatus to produce a foamed molded product according to the present invention (footwear sole material in this embodiment). The results of the test are shown in the lower column of the table.

In the above embodiment, a sole material for footwear was produced as a trial. In addition, foamed molded articles such as supporters and pads for maintaining the rest of the affected area, cushioning members for sports equipment, toys such as dolls, and pads for clothing. Can be applied to

At the time of manufacture, the temperature of the cylinder of the injection machine should be lower than the decomposition temperature of the foaming agent. That is, the limit is 140 ° C., and the preferred temperature is around 110 ° C.

The temperature of the hot plate is higher than the decomposition temperature of the foaming agent. Here, the decomposition temperature of azodicarbonamide is 19
The temperature is 0 to 230 ° C, but since stearic acid is added as a stabilizer, foaming actually starts at 160 ° C.

If the temperature of the mold is raised to cause rapid foaming, uneven foaming may occur. Therefore, it is desirable to control the temperature near the decomposition start temperature (170 ° C.).

In Table 2, azodicarbonamide is used as a blowing agent, but N, N'-nitrosopentamethylenetetramine can be used. However, in this case, since the decomposition temperature is low and the amount of gas generated is large, it is necessary to consider this point.

[0026]

[Table 2]

[0027]

As described above, according to the present invention,
By foaming the resin mixture mainly composed of EVA by injection molding in the above procedure, it is possible to obtain a lightweight and flexible foamed molded product while reducing the number of manufacturing steps. It is possible to eliminate waste of the mixture, to eliminate uneven distribution of the material resin in the mold, and to greatly improve the quality of the molded product.

Further, by arranging a frame equipped with a plurality of hot plates and dies for one injection molding machine, it is possible to reduce the number of steps.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between a mold and an orifice of an injection molding machine, (a) a state in which upper and lower molds are aligned, (b) a state in which a resin injection port of the injection molding machine is in contact, and (c) a mold. Open and expanded

FIG. 2 is an assembled state diagram of a mold and an injection molding machine.

FIG. 3 is a diagram showing a plurality of pressurized / heated mold installation states.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Injection molding machine 11 Die 12 Orifice 13 Hot plate 14 Molded product 15 Frame 16 Ram 17 Cylinder 18 Track 19 Hopper 20 Cylinder Y Yoke C Column

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[Procedure amendment]

[Submission date] February 15, 2002 (2002.2.1
5)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 2

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 3

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Claim 4

[Correction method] Change

[Correction contents]

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a resin mainly composed of EVA, for example, EV.
The A 75-85 wt%, ethylene pro Pilet Ngomu (EP
A resin mixture obtained by adding a crosslinking agent and a foaming agent to a resin having R) of 15 to 25% by weight is injected into a mold by an injection molding machine, and the molded product is opened from the mold to 1.3. Expanded and expanded by a factor of ~ 1.8 to obtain ethylene-vinyl acetate copolymer 7
5-85 15-25 weight% ethylene propylene les Ngomu
A resin mixture in which a crosslinking agent and a foaming agent are added to a mixed resin with a weight%, and a kneading adjustment, and the resin mixture is supplied to an injection molding machine and melt-kneaded at a decomposition temperature or lower of the foaming agent,
A step of injecting and molding the melt-kneaded resin mixture into a mold heated to a temperature not lower than the decomposition temperature of the foaming agent, a step of releasing the molded article from the mold to expand and expand, and a step of removing internal stress. In the above method for manufacturing a sole material for footwear, the injection molding machine and a plurality of frames equipped with a heating / pressing mold are relatively movable and can be sequentially coupled. .

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

In the ratio between EVA and EPDM, EVA
Is too large, the abrasion resistance is lowered, EVA is less Itoki
Flexibility and oil resistance is impaired is.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

[0014]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 illustrates the relationship between a mold 11 and a resin mixture injection orifice 12 of an injection molding machine. FIG. 1A shows a state in which an upper mold 11a and a lower mold 11b are pressed by a hot plate 13; FIG. 2B shows a state where the resin mixture injection orifice 12 of the injection molding machine 10 (see FIG. 2) is brought into contact with the mold 11, and FIG. This figure shows a state where the mold is opened from the mold 11 and expanded.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction contents]

Further, it is possible Oh gel labor savings by placing the frame, which has several hot plate and the mold to a single injection molding machine.

[Procedure amendment 8]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // (C08L 23/08 (C08L 23/08 23:16) 23:16) B29K 19:00 B29K 19:00 23: 00 23:00 105: 04 105: 04 B29L 31:50 B29L 31:50 31:52 31:52 F term (reference) 4C081 BC01 BC02 CA051 CB051 CC05 DA16 EA05 4F050 AA01 AA06 BA01 BA38 BA56 HA58 JA01 4F074 AA22 AA25 BA13 BA16 CA23 CC04X CC22X CC32X DA36 DA38 DA45 DA53 4F206 AA09 AA45 AG20 AH59 AH81 JA04 JC01 JN16 JN35 4J002 BB061 BB152 GB01 GC00

Claims (11)

[Claims] 1. A resin mixture obtained by adding a crosslinking agent and a foaming agent to a resin mainly composed of an ethylene-vinyl acetate copolymer is injection-molded into a mold by an injection molding machine, and the molded product is released from the mold. Molded product obtained by foaming 1.3 to 1.8 times. 2. The resin comprising ethylene-vinyl acetate copolymer as a main component comprises 75 to 8 ethylene-vinyl acetate copolymer.
The foamed molded product according to claim 1, wherein 5% by weight and 15 to 25% by weight of ethylene propyne rubber are used. 3. The foam molded article according to claim 2, wherein the ethylene tropine rubber is an ethylene propyne diene copolymer. 4. An ethylene-vinyl acetate copolymer 75 to 85.
And a kneading adjustment of a resin mixture obtained by adding a cross-linking agent and a foaming agent to a resin mixture of 15% to 25% by weight of ethylene propyne rubber, and supplying the resin mixture to an injection molding machine to form a foaming agent. Melt-kneading at or below the decomposition temperature of the melt-kneaded resin mixture, injection molding into a mold heated above the decomposition temperature of the foaming agent, and a step of releasing the molded product from the mold and expanding the foam, A method for producing a foamed molded product comprising a step of removing internal stress. 5. The method according to claim 4, wherein the blowing agent is azodicarbonamide. 6. The method according to claim 4, wherein the blowing agent is N, N′-dinitrosopentamethylenetetramine. 7. The method for producing a foamed article according to the above, wherein the injection molding machine and a plurality of frames equipped with a heating / pressing mold are relatively movable and can be sequentially joined. Manufacturing equipment. 8. Footwear soles obtained according to any of claims 1 to 7. 9. A component of a sporting goods obtained according to claim 1. 10. A supporter for resting an affected part obtained according to any one of claims 1 to 7. 11. A clothing pad obtained according to any one of claims 1 to 7.