JPH03284201A - Making of polyurethane injection molded shoe - Google Patents

Abstract

PURPOSE:To perfectly check the production of inferior shoes caused by insufficient injection even if cut grooves are not provided, by a method wherein even if both an upper member and an upper-reinforcing member with poor air- permeability are used, a number of fine permeable pinholes, which are hard to be recognized by the naked eye, are formed on the surface thereof. CONSTITUTION:Both an upper member 1 and an upper-reinforcing member 2 are held on a last mold 11 together with an insole 3, and the last mold 11, a bottom mold 12 and side molds 13, right and left, are mutually press joined, and thus a sole cavity 9 is formed. After that, polyurethane material for a sole is injection filled into the sole cavity 9, and is made simultaneously foamy in that place, and a polyurethane foam-made sole 4 is formed, and is stuck on the upper members 1, 2 and the insole 3. At this time, permeable pinholes 5 are formed on the whole of the upper-reinforcing member 2 and on both up-and-down sides of a part 8 at which the upper material 1 is in contact with a projecting part of each of the side molds 13. In this way, air in the cavity 9 is run through the interiors of the upper members 1, 2 and can be exhausted outward. At the periphery of the sole, therefore, the production of inferior shoes caused by insufficient injection can perfectly be checked.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing shoes with foamed polyurethane soles (polyurethane injection molded shoes) by injection foam molding.

(Prior Art) Traditionally, polyurethane injection molded shoes are generally manufactured by first suspending laces and/or reinforcing laces into a last mold.
Next, the mold, the bottom mold, the left and right side molds, etc. are pressed against each other to form a sole cavity, and then a polyurethane material for the sole is injected into the sole cavity and simultaneously foamed there to form polyurethane foam. It is manufactured by a process of molding the sole and adhering it to the shoe material.

The lace materials and reinforcing lace materials used in this type of shoes include artificial leather, grained leather, vinyl chloride leather, and synthetic leather.

(Problem to be Solved by the Invention) However, conventional materials such as artificial leather with a grain layer on the surface have poor breathability, so when polyurethane material is injected into the shoe sole cavity, as shown in Figure 5, Air in the cavity 9 is not completely discharged to the outside, but an air pocket 15 is formed in the cavity 9, especially in the space below the slit 10 of the side mold 13, and as a result, there is a lack of injection on the outer periphery of the manufactured shoe sole. There was a problem with the occurrence of defects. In addition, in the same figure, 21
and 22 indicate a conventional splice material and a reinforced splice material.

Therefore, conventionally, a cut groove called an air vent is provided in the contact surface of the selvage portion 15 of the side mold 13 with the last mold 11, and a sole cavity 9 is provided to communicate the sole cavity 9 with the outside. Adopting the method of
The injection shortage was intended to prevent defects from occurring.

However, with this method, even if the cut groove is 0.5 to 2 m
Even if it is designed to have a size of m, the polyurethane material can get into the cut groove during injection molding.
There has been a problem in that so-called firmness tends to occur on the outer periphery of the sole of manufactured shoes. For this reason, it is necessary to incorporate an operation for removing firmness into the shoe production process after injection molding, and this operation is extremely troublesome and time-consuming, and often leads to a decline in quality.

The present invention was made in consideration of the above circumstances, and its purpose is to produce polyurethane injection molding with excellent design quality, without causing defects due to lack of injection or failure even when using materials with poor air permeability. The purpose of the present invention is to provide a method for stably manufacturing molded shoes.

(Means to Solve the Problem) The inventor of the present invention made a thorough study on improving the breathability of the woven material itself, and found that it was completely unexpected to use a woven material and reinforcing material with poor air permeability in the surface layer or the entire cross section. too,
It was discovered that by forming a large number of minute ventilation holes that are difficult to recognize with the naked eye on their surfaces, it is possible to completely suppress the occurrence of defects due to injection defects even without providing cut grooves, and the present invention was completed. I let it happen.

Therefore, the method for manufacturing polyurethane injection molded shoes according to the present invention is a method for manufacturing shoes with polyurethane soles by injection foam molding using a lace material with poor air permeability and/or a reinforcing lace material for the surface layer or the entire cross section. The above-mentioned lace material and/or reinforcing lace material, in which a large number of minute ventilation holes are formed so that it is difficult to recognize the existence of the holes, is suspended in a last mold, and then the polyurethane material for the sole is injected into the sole cavity and foamed at the same time. This shoe is characterized by a polyurethane sole.

The webbing material and reinforcing webbing material used in the present invention are made of artificial leather, synthetic leather, or PVC leather that is non-breathable or has poor breathability in the surface layer or the entire cross section, and has many fine ventilation holes on the surface of the webbing material. , preferably regularly formed.

Ventilation holes do not necessarily need to be formed on the entire surface of the material, etc., as long as they are formed only on the upper and lower sides or the lower side of the part that contacts the selvedge part of the side mold when suspended in the last mold. Enough.

In addition, the ventilation hole is a microscopic hole of such a size that it is difficult to recognize its existence with the naked eye, for example, by penetrating the bamboo material with a needle of about 10 to 30 IL in thickness, preferably from the back side.
Can be drilled.

The invention can be applied to all cases in which shoes with polyurethane soles are manufactured by injection foam molding using a lace material with poor air permeability and/or a reinforcing lace material for one surface layer or the entire cross section. In particular, the present invention is effective when artificial leather in which a non-breathable or poorly breathable grain layer is formed on the surface of a non-woven fabric base material is used as the lace material.

(Function) By providing the ventilation holes, external air on the surface side can flow into the interior of the breathable base material layer when the surface layer is made of bamboo material with poor air permeability. In the case of bamboo material, etc., which has poor air permeability throughout its cross section, it is possible to flow in from the back side thereof. Therefore, according to the method of the present invention, the air in the injection foam molded sole cavity, especially the air in the lower part of the selvage part of the side mold, passes through the inside of the reinforcing material or between the reinforcing material and the material. If there is no reinforcing material, the air can flow through the non-woven fabric of the material, absorbing air inside the non-woven fabric, and can also be drawn out from the upper side of the selvedge through the internal structure of the material. I can get out. Therefore, the entire sole cavity is completely filled with the polyurethane material, and no air pockets are generated under the selvage portion or the like.

(Example) An embodiment of the present invention will be described below.

Figures 2 and 3 show the material l used in the method of the example.
and reinforcement material 2 are shown.

As shown in FIG. 4, these lace materials 1 and 2 are artificial leathers having a grain layer 6 on the surface of a nonwoven fabric 7 as a base material, and the pores are so fine that it is difficult to recognize them with the naked eye. Air vent 5・
A large number of... are formed regularly at intervals of 2ml11.

The ventilation holes 5 are provided in the lower part of the sheath structure of the lace material 1, as shown in FIG. 2, and on the entire surface of the reinforcing lace material 2, as shown in FIG. 3.

The ventilation holes 5 have been formed, for example, by passing an artificial leather material between a metal roll and a rubber roll, each having needles having a diameter of 201 L implanted on the roll surface. Note that the method for forming the holes 5 is not limited to this.

Polyurethane shoes were manufactured using the above-mentioned materials 1 and 2. In other words, as shown in FIG.
The left and right side molds 13 and the like are pressed against each other to form a sole cavity 9, and then a polyurethane material for the sole is injected into the sole cavity 9 and simultaneously foamed there to form a polyurethane sole 4. 1.
A polyurethane injection molded shoe was produced by adhering the polyurethane material 2 and the insole 3.

In the embodiment, ventilation holes 5 are formed in the entire reinforcing splice material 2 and on both upper and lower sides of the portion 8 of the splice material 1 that contacts the selvedge portion of the side mold 13, so that the air in the cavity 9 flows through the first As shown by arrows a and b in the figure, it flows inside the spruce materials 1 and 2 and can be extracted to the outside. Therefore, no injection defects or defects were observed on the outer periphery of the soles of the manufactured shoes.

(Effects of the Invention) As described above, the manufacturing method according to the present invention makes it possible for air in the sole cavity to completely escape to the outside, in other words, it is possible to completely fill the cavity with polyurethane material. As a result, shoes with foamed polyurethane soles can be reliably manufactured by injection molding without causing defective injections, poor firmness, etc. on the outer periphery of the sole.

Moreover, even if there are a large number of ventilation holes, the present invention is difficult to recognize with the naked eye, and does not impair the appearance of the manufactured shoe product in any way.
It has the advantage of exhibiting the desired design effect.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a diagram showing the manufacturing process of polyurethane injection molded shoes according to the method of the embodiment of the present invention, and Fig. 2 is a diagram showing the process of manufacturing polyurethane injection molded shoes according to the method of the embodiment of the present invention. Figure 3 is an exploded view of the reinforcement material used in the polyurethane injection molded shoe of Figure 1. Figure 4 is an enlarged view of the inside of the reinforcement material of Figure 2 and Figure 3. 5 is a diagram illustrating the manufacturing process of a polyurethane injection molded shoe according to a conventional method. In the figure, 1.. 3.. 5.◆ 7.φ 8.. lO. 11. 12. 13. 15. a, b - Reinforcement material, sole, silver layer, sole cavity, material 2.・Insole 4... ・Minute ventilation holes 6... ・Non-woven fabric 9... ・Contact area with the seri section ・Seri section ・Last mold ・Bottom mold ・・Side mold ・・Air pool... The way to remove air

Claims (1)

[Claims] (1) In the method of manufacturing shoes with polyurethane soles by injection foam molding using a lace material with poor air permeability and/or a reinforcing lace material for the surface layer or the entire cross section, holes are so minute that it is difficult to recognize them with the naked eye. The above-mentioned lace material and/or reinforcing lace material having a large number of ventilation holes are suspended in a last mold, and then a polyurethane material for soles is injected into the sole cavity and simultaneously foamed to form a foamed polyurethane shoe sole. Method of manufacturing polyurethane injection molded shoes.