JPS6048161B2 - Manufacturing method for two-color shoe soles made of polyurethane foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a two-color shoe sole made of polyurethane foam. Improving the adhesive strength between the primary polyurethane foam layer (hereinafter referred to as the 1st layer) corresponding to the bottom and the secondary polyurethane foam layer (hereinafter referred to as the 2nd layer) corresponding to the intermediate sole, and increasing manufacturing efficiency. The present invention provides a manufacturing method that makes it possible to

It has been known to form a shoe sole with two color-coded layers in the vertical direction of the side part of the shoe sole using polyurethane foam. There is a big problem.

That is, a predetermined amount of a first stock solution 6 of foamable polyurethane is injected into a first cavity 5 formed by setting a bottom mold 1, a side mold 2, a lid mold 3, and a dummy mold 4 (FIG. 1). 6 is foamed and hardened to form the first
Layer 6' and no (Fig. 2), each mold set is unraveled, the dummy mold 4 is removed to create a second cavity 7, and a second stock solution 8 of foamable polyurethane is injected into the second cavity 7 ( (Fig. 3), the second layer 8'' is formed integrally with the first layer 6'' by foaming and curing (Fig. 4), and each mold set is unwound to obtain the desired two-color shoe sole 9 (Fig. 4). Figure 5). In this case, the inner surface of each mold 1, 2, and 3 is coated with a mold release agent in advance, but the dummy mold 4 is not coated with a mold release agent, and is instead made of a material with good mold release properties. A mold may be prepared using resin, rubber, etc., or the surface of the dummy mold may be surface-treated with a resin, rubber, etc. with good release properties, or an appropriate release sheet may be used. 10(
(Teflon resin sheet, Teflon iron plate, etc.) (see Figure 1).

The reason why a mold release agent is not applied to the surface of the dummy mold 4 is that if a mold release agent is applied, the mold release agent will adhere to the surface of the first layer and prevent adhesion with the second layer. .

Of course, it is possible to bond the first and second layers by wiping off the adhering mold release agent, but in reality, the mold release agent penetrates into the inside of the first layer. This is because it is undesirable because it tends to make the removal work difficult and increases the number of man-hours. Now, as described above, in the process of implementing the two-color sole as shown in FIGS. 1 to 5, the inventors discovered the following major problem. That is, first of all, even though the sheet 10 which inherently has mold releasability is interposed on the contact surface with the first layer of the dummy mold, it is extremely difficult to separate the sheet 10 from the first layer. .

Second, the adhesion of the mold release agent to the surface of the first layer is eliminated and the second layer is
Although the attempt was made to strengthen the adhesion between the first and second layers, an unexpected and abnormal gas pocket 11 was created at the joint surface of the first and second layers. Similarly, the adhesive strength between both layers is significantly reduced. As a solution to these problems, the applicant previously proposed
01 invention. This is an attempt to solve the above problem by interposing a separate sheet material between the first and second layers! However, the cut edges of the sheet material are visible on the sides of the bottom, which is not desirable in terms of design and is complicated to work with. Further, according to an invention disclosed in Japanese Patent Application Laid-Open No. 57-20201, a mold is constructed with a mold-releasing resin, and fine irregularities are formed on the inner surface of the mold to form a first layer and a second layer. Although the adhesive force of the layer is strong, it is time-consuming to process the uneven surface, and the life of the uneven surface is short, so there are no practical problems.

The present invention has been completed through repeated research in view of these problems.

That is, the present invention includes a bottom mold 1, a side mold 2, and a lid mold 3.
A predetermined amount of the first stock solution 6 of foamable polyurethane is injected into the first cavity 5 formed by setting the dummy mold 4, and is foamed and hardened to form the first layer 6''.Then, the mold is unset and the dummy mold is formed. 4 is removed to form a second cavity 7, and a second stock solution 8 of foamed urethane is injected into the second cavity 7 and foamed and hardened) to form a second layer 8'' integrally with the first layer 6''. In the method for manufacturing the colored shoe sole 9, the volume of the first cavity 5 is expanded by the curved concave surface 12 formed over almost the entire lower surface of the dummy mold 4, and the first cavity 5 is
original. The liquid 6 is supplied without coming into contact with the dummy mold 4 and is distributed throughout the uneven pattern 13 on the bottom surface of the bottom mold 1, and then this first stock liquid 6 is foamed and hardened in the enlarged first cavity 5. This relates to a method for manufacturing a two-color shoe sole made of polyurethane foam, characterized in that the first layer 6'' is molded, and the second layer 8'' is integrally molded with the first layer 6'' in a conventional manner. An embodiment of the manufacturing method of the present invention is shown in the order of steps in Figures 1 to 10.

In the present invention, for example, as is clear from FIG.
The internal volume of the cavity 5 is expanded by the curved concave surface 12 on the lower surface of the dummy mold 4, and the first stock solution 6 is foamed and hardened within this enlarged first cavity 5, so the foaming of the first stock solution 6 is free foaming. (Foaming pressure 0.6-1.0k91d)
As a result, a large number of fine bubbles bulge out on the surface of the first layer 6'' obtained by foaming and hardening.Therefore, during the next injection of the second stock solution 8 and foaming and hardening, there will be excess foaming. Since the gas is absorbed into the surface of the first layer 6'' or escapes through it, no gas accumulation occurs at the adhesive interface between the first layer 6'' and the second layer 8''. Also, the first layer 6'' and the second layer 8
The adhesive interface of `` is molded into a single piece due to the anchoring effect, and a large adhesive force is obtained.Furthermore, in the present invention, the first stock solution 6 is supplied so as to be distributed throughout the uneven pattern 13 on the bottom surface of the bottom mold 1, and then the foaming process is performed. Since it is hardened, the uneven pattern 13'' can be clearly revealed even though the foaming type is close to free foaming as described above.

In contrast, when using conventional technology, this kind of 2
In the case of monolithic molding (mechanical molding) of colored bottoms, it is difficult to inject the stock solution into the cavity due to the mechanism of the mechanical device, and it is difficult to form a flow or injection into the bottom surface of the bottom mold, and injection or injection is performed exclusively in the horizontal direction. A type of method was used. Therefore, the first
It is difficult for the stock solution to spread into the uneven pattern of the bottom mold, making it difficult to form a clear pattern.To compensate for this, it is common sense to use a suppressed foaming method in which the foaming pressure is increased to 1.0 to 2.0k91d. It has been. Therefore, the surface of the first layer 6'' is pressed against the surface of the dummy mold 4 during foaming and curing, forming a dense film, and there is no place for the metal bubble gas of the second layer 8'' to escape, resulting in gas accumulation. The result would have been 11.

Incidentally, the specific gravity of the first layer 6'' according to the prior art is 0.7 to 1.
．． 1 and that of the present invention (4). 5 to 0.7).

Further, in the conventional technique, as mentioned above regarding the drawbacks of the conventional method, even if a releasable sheet or the like is used in the dummy mold, it is difficult to separate it from the first layer 6''.

In contrast, in the present invention, the first layer 6'' and the dummy mold (release sheet 10) can be separated very easily.
″ is strongly pressed against the surface of the dummy mold,
In the present invention, since the format is close to free foaming, such pressing is unlikely to occur, and the first stock solution 6 injected into the bottom mold has almost passed the tack-free time (from 6 to 70 minutes).
This is because it will come into contact with the bottom surface of the dummy mold after 8 (18). In this way, the present invention replaces the conventionally common method of horizontally injecting or casting the first stock solution with the method of directly injecting or injecting the first solution into the uneven pattern at the bottom of the bottom mold, which at first glance appears to be a polyurethane foam bottom. By returning to the traditional shoe-making technology that has 2-color soles and combining it with free foaming, which is an unusual method for this type of technology, we have solved the two major drawbacks of simultaneous molding of two-color soles all at once. I was able to do that.

In the present invention, the curved concave surface 12 on the lower surface of the dummy mold 4 is
For example, as shown in FIG. 6, one curved concave surface 12 may be formed so as to cover almost the entire lower surface;
As shown, several curved concave surfaces 12 may be formed.

If the inner volume of the curved concave surface 12 is too large, the inner volume of the first cavity 5 will be expanded too much, and the first layer 6'', which is the outer sole, may be chipped or become too soft, resulting in an extremely low strength. There is a risk of causing undesirable results such as
If it is too small, the internal volume of the first cavity 5 will not be sufficiently expanded, and the first layer 6'' will be molded with suppressed foaming.
Since the intended purpose cannot be achieved, the first cavity 5
approximately 1.3 to 2.5 times the internal volume, preferably,
It is preferable to have a size that can be expanded by about 1.5 to 2 times.

In addition, the internal volume and shape of the curved concave surface 12 can be designed in various ways, such as large and small, regular, irregular, etc., depending on the intended part of the sole. If the shape and internal volume of the curved concave surface are designed in advance so that the specific gravity is slightly higher, and the specific gravity is slightly lower in parts that do not require much hardness, such as the treading part, then the entire part can be molded to the same thickness. The first in the conventional sole of this kind
Not only can you obtain a sole with more functionality than layers, but also the first layer.
The amount of stock solution used can be reduced. Although it is preferable that the surface of the curved concave surface 12 be smooth, slight irregularities do not pose any problem in achieving the object of the present invention.

In short, the curved concave surface 12 of the dummy last 4 forms the upper surface of the first layer 6'', and is eventually completely covered by the second layer 8'' and does not appear on the surface of the product at all, so that the upper surface of the first layer 6'' is completely covered. The irregularities, distortions, and irregular shapes can be freely designed to the extent that they do not inhibit mold release or adhesion to the second layer 8'' in the next step. In the present invention, instead of the lid type 3, a last 3'' (
6, 9, and 10), it is possible to manufacture shoes with desired two-color soles all at once.

In the present invention, a parting line 14 is formed between the bottom mold 1 and the side 2, that is, along the outer peripheral boundary line between the first layer 6'' and the second layer 8''.

During molding of the first layer 6'', a part of the first stock solution 6 enters into the parting line 14, causing an overflow 15.This overflow 15 serves as a backing for the second stock solution 8 from the next step onward. Furthermore, by cutting off this protrusion 15 after molding the second layer 8'', the boundary line between the first layer 6'' and the second layer 8'' can be clearly seen along the mold parting line 14. I can put it out. In the present invention, the casting means for the first stock solution plays an important role, that is, it is necessary to cast a predetermined amount into the bottom of the bottom mold 1 by flowing or pouring.

Preferably, in a flowing state, the injection port is moved back and forth and left and right so that the injection port completely covers the uneven pattern on the bottom surface of the mold 1. At this time, it is necessary to prevent the first stock solution from adhering to the dummy mold. If the first stock solution adheres to the dummy mold before the tack-free time has elapsed, it tends to make it difficult to separate the two. Therefore, the first stock solution needs to be poured or poured into the open bottom mold 1 before the first cavity is set. It is necessary to carry out the process so that the dummy mold stock solution does not adhere to at least the first cavity. It is necessary to adjust the blending prescription and casting amount in advance so that the specific gravity between the first layer of the two-color shoe sole obtained in the present invention is finally in the range of 0.50 to 0.70. It is. This is because when the specific gravity is 0.70 or more, it deviates from the free foaming range described above, and two breakouts in the conventional method occur. Moreover, when the specific gravity is 0.50 or less, the first stock solution 6 is
This is because there is a very high risk that the first cavity will not be filled and a serious omission will occur. The specific gravity of the second layer 8″ of the two-color sole obtained in the present invention is 0.40 to 0.60.
Adjust in advance so that it is within the range! It will be arranged.

This is a preferable range that can be put to practical use as the intermediate sole portion of this type of two-color sole. What should be noted is that
The means for casting and foaming the second stock solution 8 forming the intermediate bottom may be injection molding or injection molding, but in short, there is no restriction in terms of the method in order to fill the second cavity. As mentioned above, the first cavity is
This is very different from being subject to restrictions. Examples of the present invention are listed below. Example (1) Bottom mold Material Aluminum Capacity Approximately 160cc~180cc Temperature 40℃~45℃ (2) Cymold Material Aluminum Temperature 40℃~45℃ (3) Lid Mold Material Aluminum Temperature 40℃~45℃ [Phase] Release sheet Material: Teflon or polyethylene Thickness: Sheet, thickness: 0.5? ~0.6 sugar (4) Dummy mold Material Aluminum Concave capacity Approximately 120cc ~ 160cc Temperature 3 (s)
~40℃ Mold release agent component (trade name, Mirax RSlO2: manufactured by Mitsui Nisso Urethane Co., Ltd.
Mold release agent) Once the above (1), (2), and (3) are combined, spray the above mold release agent on the inner surface, uncombine the mold, and pour the following first stock solution into the bottom mold. Type.

Composition of the first stock solution (parts by weight) Solution A Polybutylene adipate 50.00
4-4″ diphenylmethane 61.00 Liquid B Polybutylene adipate 92.00 Triethylenediamine 0.70 Water 0
．． 30 Stabilizer, foam stabilizer 2.

00 Pigment 5.00 Above A. ．． B. Both solutions are mixed. In that case, the tack-free time is 6 to 8 minutes, and the time for demolding is 2 to 6 minutes.

Cast 80y to 100g of this liquid.

For casting, Nippon Polyurethane Engineering Co., Ltd. P
Using an EC casting machine, inject the stock solution in a flowing state.

At this time, the casting spout was moved back and forth to ensure that the solution was evenly distributed within the uneven carvings of the bottom mold. Immediately, molds (1) to (4) are combined to form a first cavity.

At this time, the release sheet 10 was previously provided with irregularities along the depressions on the bottom surface of the dummy mold. Further, the peripheral portion of the release sheet was sandwiched between the parting lines 14 of the molds 1 and 2. After 1 to 4 minutes, the mold was unassembled and the release sheet 10 was peeled off from the first layer 6''.

This peeling could be easily performed. The following second stock solution was poured into the recess created by combining side mold 2 again.

Composition of the second stock solution (parts by weight) Solution A Polybutylene adipate 50.004"4" diphenylmethane 61.00 Solution B Polybutylene adipate 94.00 Triethylenediamine
0.65 Water 0.35 Stabilizer, antifoaming agent 2.00 Pigment 3.00 Above A. Mix B solution, in that case tack free time 6 to 8 mackerel demolding time
100' to 12 minutes of this solution for 4 to 6 minutes.
0y was cast.

Immediately close lid mold 3. After 6 minutes, the mold was released.

In the resulting two-color sole, no gas pockets were observed at the boundary between the first and second layers, which were clearly adhered together.

In addition, the product comparison shows that the first layer is 0.60 to 0.70, the second layer is 0.45 to 0.55, and the adhesive strength between the first layer and second layer is 4.0 to 5.0k9.
1c! At t, the material exhibited a state of failure.

The first layer at the tip of the toe has a specific gravity of 0. The adhesive strength with the second layer is 1.0-1.2kg1c! It was t. )

[Brief explanation of the drawing]

1 to 5 are explanatory diagrams showing an example of a conventional manufacturing method in the order of steps, FIGS. 6 to 11 are explanatory diagrams showing an example of the manufacturing method of the present invention in the order of steps, and FIG. 12 is an explanatory diagram showing an example of the manufacturing method of the present invention in the order of steps. FIG. 13 is a vertical cross-sectional view showing a product molded using the dummy mold shown in FIG. 12. In the figure, 1 is the bottom mold, 2 is the side mold, 3 is the lid mold, 4 is the dummy mold, 5 is the first cavity, 6 is the first stock solution, 6'' is the first layer, 7 is the second cavity, 8 is the 2
undiluted solution, 8'' is the second layer, 9 is the two-color sole, 10 is the release sheet, 11 is the gas reservoir, 12 is the curved concave surface, 13 is the uneven pattern, 14 is the parting line, and 15 is the protruding part.

Claims (1)

[Claims] 1. A predetermined amount of a first stock solution of foamed polyurethane is injected into a first cavity formed by setting a bottom mold, a side mold, a lid mold, and a dummy mold, and is foamed and hardened to form a first layer. Unset the mold, remove the dummy mold, create a second cavity, inject a second stock solution of foamed polyurethane into the second cavity, foam and harden it, and mold the second layer integrally with the first layer. In the method for manufacturing a two-color shoe sole, the volume of the first cavity is expanded by a curved concave surface formed over substantially the entire lower surface of the dummy mold, and the first stock solution is placed in the expanded first cavity as a dummy mold. The first stock solution is supplied so as to be distributed throughout the uneven pattern on the bottom surface of the bottom mold without contact, and then the first stock solution is foamed and hardened in the enlarged first cavity to form the first layer. street,
A method for manufacturing a two-color shoe sole made of polyurethane foam, characterized in that the second layer is integrally molded with the first layer. 2. In order to impart releasability to the lower surface of the dummy mold, the dummy mold is made of a resin with good releasability such as Teflon or polyethylene, or a film or sheet made of such resin is coated on the lower surface of the dummy mold. A method for manufacturing a two-color shoe sole according to claim 1, characterized in that: 3. A patent claim characterized in that when molding the second layer from the second stock solution in the second cavity, a last to which the cover is attached is used as a lid mold, and the second layer and the cover are integrally molded. A method for manufacturing a two-color shoe sole according to item 1.