JPS6120502A - Mid-sole comprising foamed polyurethane and its production - Google Patents

Abstract

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

Description

[Detailed description of the invention] (a) Industrial application field The present invention is a midsole that is attached between an outsole and a shoe cover, which maintains cushioning properties while running and prevents sideways vibration. The present invention relates to a midsole made of foamed polyurethane that has both shock absorption and stability, and a method for manufacturing the same.

(b) Conventional technology During running, the lower limbs move inward so that the lower limbs land on the center line of the body. This movement also acts as a rolling phenomenon of the inside of the foot after landing. Particularly during long-distance running or jogging, landing is often done from the heel, but when landing, an impact of 2.5 to 3 times the body weight is applied, and the pressure applied to the rear foot after landing is due to the external heel of the foot. It moves from the side to the medial side via an external arching curve, and the structure of the joint between the giant bones and the calcaneus is also taken into account, and force is applied to the medial side of the heel.

In recent years, with the development of polymer chemistry, high-quality foams have been developed and are used in midsoles and heel wedges of running shoes, greatly reducing the impact of landing. However, the improved heel stability promotes a certain degree of rolling when landing and shifting weight, making running unstable.If you continue running in this state, the rolling becomes even more excessive (overpronation), resulting in the heel Running injuries to the knees and other areas can occur due to unnatural force being applied to the knees.

In order to overcome such injuries, conventionally, at least a part of the heel part of the midsole or the inner part from the heel part to the non-stepping part is deformed, and the remaining part is made of a hard layer with good cushioning properties. Efforts have been made such as forming it with a shock absorbing layer.

However, when a high hardness part is required, these methods involve combining and joining completely separate bottom materials, which requires time and effort to cut each part, and requires processes such as joining with adhesive. The work is complicated, and the hardness and quality of each part differs, so it is difficult to make a product with stable quality because these parts are assembled and joined together.
The problem was that it could not be manufactured cheaply.

(c) Purpose of the Invention The present invention is a method of integrally molding a single material through the troublesome process of combining and joining completely separate parts in parts that require hardness to obtain a desired midsole. By this, it is possible to form a part with the required hardness at the desired location,
The object of the present invention is to provide a midsole that maintains cushioning properties while running, prevents lateral vibration, and has both shock absorption and stability, and a method for manufacturing the same.

(d) Structure of the Invention The present invention consists of a polyester-based urethane foam installed between the outsole and the heel. An appropriate number of holes are formed on the outside side of the heel on at least one side of the heel covering side and the ground contact side, and a hard skin layer is formed around these holes to form a hard skin layer on the inside side of the heel. The four parts are configured such that the compressive displacement of the upper part is smaller than the compressive displacement of the outer part, and the upper part and one part part are combined to form a midsole having a contour that roughly follows the main sole. ,
In a method for manufacturing a midsole made of foamed polyurethane, a liquid polyester-based urethane material is injected or injected into the portal and subjected to a foaming and curing reaction to form a skin layer on the surface of the foam that is in contact with the inner surface of the upper and lower molds. A suitable number of protrusions are provided on at least one side of the mold or upper mold at a position corresponding to the outside side of the heel of the heel. It consists of being

The volustel type urethane foam that becomes the midsole of the present invention is made of 4,4-diphenylmethane diisocyanate,
Diisocyanates such as 4,4”-dicyclohexylmetadiisocyanate, glycols such as ethylene glycol and 1,4-hexanediol, adipate-based polyethylene adipate, poly(1,4-butylene adipate)
This is a urethane foam obtained by reacting a polyester diol such as poly (1,6-hexane adipate).

(e) Embodiment Figure 1 shows the first embodiment of the present invention, which consists of a polyester urethane foam installed between the outsole and the cover. A plan view of the midsole formed to follow the contour; FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1; and FIG. It is a front view.

The above-mentioned midsole has an appropriate number of holes that open on the side of the heel of the heel, and in particular, the number of holes (1) arranged along the inner heel side is greater than the number of holes (1) arranged along the outer heel side. The number of holes (2) is greater than the number of holes (2). A suitable number of the above holes are arranged on the inner and outer laces, but the hole (1) on the inner lace, which is closest to the toe side, is closest to the toe side. It is formed closer to the toe side than the hole (2) on the outside side. Of course, the toe side positions of the hole (1) on the inner heel side and the hole (2) on the outer heel side may be arranged in parallel.

The above midsole is formed as follows. A recess corresponding to the midsole formed by combining the upper mold (3) and the negative mold (4) is formed. These four parts include an appropriate number of holes (1) to be arranged in the heel part of the midsole,
There are protrusions (1) and (2) of a desired shape implanted on the inner surface of the upper mold (3) so as to match (2). A liquid polyurethane material that will become the midsole is injected or injected into each of the four parts to cause a foaming reaction. Upper mold (
3) The inner surface temperature of the lower mold (4) is maintained at approximately 40-45°C, and the material temperature during injection or pouring is approximately 40-45°C.
The temperature is about 5°C. If the thickness of the heel is normal, the internal material temperature due to reaction heat will be approximately 95 to 100 degrees Celsius.
If it is thick, it can reach up to about 150 degrees Celsius.

Therefore, the inner surface and protrusion (1) of the upper mold (3) and lower mold (4)
.

Since the surface temperature of (2) is relatively lower than the material temperature during the reaction, a skin layer with insufficient foaming and high hardness is formed on the outer surface of the foam that is in contact with these surfaces, and the inner surface is A foam is formed which undergoes a sufficient foaming and hardening reaction.

After that, the upper mold (3) and lower mold (4) are released from the combination, and the midsole made of foamed polyurethane is taken out.

As mentioned above, the hole formed in the heel of the midsole is not formed after the foam is formed, which has a contour that roughly follows the outsole, but is formed integrally with the molding of the midsole. A skin layer with high hardness is formed around the hole, similar to that formed on the outer skin of the midsole.

This hole is provided substantially perpendicularly to the ground side surface, and since the skin layer is formed in a cylindrical shape around this hole, it can withstand compressive pressure from above extremely well.

The shape of the protrusion may be a cylinder, a triangular prism, a polygonal prism, a columnar shape such as an elliptical, star-shaped, gourd-shaped cross section, or a truncated cone or a truncated pyramid. .

Among the above shapes, cylindrical shapes and elliptical cylindrical shapes with longer diameters in the inner and outer lateral directions are easy to mold, and the skin layer formed around the holes formed in the midsole has good shape retention. .

As described above, in this embodiment, holes are provided that open on the side surface of the heel of the midsole, and since many of these holes are formed on the inner heel side, a cylindrical shape is formed around these holes. The highly hard skin layer acts as a reinforcing wall, and the hole is sealed by the inner sole on the side of the cover.
It functions as a rubber ball and can sufficiently withstand compressive pressure applied from above, and can also act as an air action to cushion and absorb shock. Since it is smaller than the displacement, it is possible to prevent overpronation, where the lower part of the ankle twists and tilts too much to the inward side during the period from when the foot touches the ground until it kicks off when running.

FIG. 4 shows the second embodiment, and shows a longitudinal cross-sectional view of the midsole in the same way as FIG.
) is a vertical cross-sectional view showing a state in which they are assembled. The difference from the first embodiment is the shaped upper mold (3゛) and lower mold (4゛).
Protrusions (1'), (2') on the inner surface of the recess on the lower mold side of °)
It is planted in such a way that it is present. Therefore, an appropriate number of holes (1) are formed in the heel of the midsole.
(2) is formed to open on the ground plane side. The rest of the structure is the same as that of the first embodiment.

According to this embodiment, since the hole opening on the ground surface side is provided, the hard cylindrical skin layer formed around the hole is a flat outer surface skin layer or sponge layer on the side surface of the cover. Since it does not directly touch the wearer's feet, it feels even better on the feet.

Although the third embodiment is not shown in the drawings, the hole is not limited to the one in which holes are formed only on the covered side of the heel of the midsole or only on the grounding side. This is a mid-sole that is formed so as to be open at a ratio between the covered side and the ground-contact side. Further, the hole in the midsole may be formed so as to penetrate through the side surface of the shoe and the ground contact side (1). Therefore, in this embodiment, the protrusions (1') and (2') are implanted so as to be present on the inner surfaces of the recesses of both the assembled upper mold (3') and lower mold (4').

According to this embodiment, the number of holes formed so as to open on the side surface of the cover is equal to the number of holes formed so as to open on the ground side surface.
Differences in hardness can be made smoothly by distributing δ.

(F) Effects of the Invention As described above, the present invention provides a midsole made of polyester urethane foam that is formed in a contour that substantially follows the outsole, and has a heel heel w, a side surface, and at least one surface of the ground contact surface. An appropriate number of holes are formed on the outer side of the hole, and a hard skin layer is formed around these holes.
Since the compressive displacement is smaller than that of the inner heel side of the heel, the excessive pronation of the foot that occurs during running causes the inner heel side to be larger than the outer heel side. This can be done without distortion, and the occurrence of overpronation can be prevented.

In addition, since the highly hard skin layer around the hole is integrally molded, it can withstand long-term use without adhesive separation.
Moreover, the manufacturing process is simple and can be formed easily.

In addition, these holes are particularly formed in the thick heel area to prevent wrinkles from forming during the molding of the midsole. They also provide shock absorption and stability.

[Brief explanation of drawings]

Fig. 1 is a plan view showing the midsole of the first embodiment of the present invention, Fig. 2 is a sectional view taken along A-A 4'J in Fig. 1, and Fig. 3 shows an upper mold forming the midsole in Fig. FIG. 4 is a longitudinal cross-sectional view showing a state in which the lower mold is assembled, and FIG. 4 is a cross-sectional view showing the midsole of the second embodiment. (1), (2)...hole, (1'), (2'
)...protrusion, (3). (3゛)...upper mold, (4), (4')...lower mold,
(5), (5')...four parts.

Claims (7)

[Claims] (1) In the midsole, which is made of a polyester urethane foam that is installed between the outsole and the sole, the foam has a contour that roughly follows the outsole. An appropriate number of holes are formed on the outer side of the heel on one side, and a highly hard skin layer is formed around these holes, so that the compression displacement of the inner heel side of the heel is reduced to the outer heel side. A midsole made of foamed polyurethane, which is constructed so that the compressive displacement of the parts is smaller than the compressive displacement of the parts. (2) The midsole made of polyurethane foam according to claim 1, wherein the appropriate number of holes are formed more on the inner heel side than on the outer hem side. (3) The hole located closest to the toe side of the appropriate number of holes is configured so that it is not on the outer side but on the inner side. Midsole made of polyurethane foam as described. (4) The midsole made of polyurethane foam according to claims 2 and 3, wherein the inner wall area of the appropriate number of holes on the outer side is smaller than the inner wall area of the holes on the inner side. . (5) Combining the upper mold and the lower mold to form a recess for forming a midsole with an outline that roughly follows the outsole, and injecting or injecting liquid polyester-based urethane material into the recess to harden the foam. In the manufacturing method of a midsole made of foamed polyurethane which reacts and forms a skin layer on the surface of the foam that is in contact with the inner surface of the upper and lower molds, A method for manufacturing a midsole made of foamed polyurethane, characterized in that an appropriate number of protrusions are protruded on at least one side of an upper mold or a lower mold at a position corresponding to the outer side. (6) The polyurethane foam according to claim 5, wherein the appropriate number of protrusions are protruded from positions corresponding to the inner heel side of the heel portion of the midsole than the outer heel side. A method of manufacturing a midsole consisting of: (7) A patent claim in which the projections located close to the toe side corresponding to the midsole of the appropriate number of projections are configured such that they are on the inner heel side of the heel portion of the midsole rather than the outer heel side. A method for producing a midsole made of polyurethane foam according to item 5 and item 6.