JPS6131101A - Midsole - 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) Field of Industrial Application The present invention relates to a midsole that can enhance running functionality and improve moldability.

(B) Conventional technology - In recent years, in order to reduce the impact on the feet when driving on stone roads, concrete paved roads, etc., the soles of footwear have changed to sponge soles, and even thick PZ sponge soles have been adopted depending on the function. It is designed to be used. In such soles, the outsole is made of a solid or wear-resistant material, I! It is common for a sole to have one or a suitable number of sponge layers with good cushioning properties between the outsole and the cover, and this layer is called a midsole. This mid-sole requires a certain degree of hardness and is quite thick, and requires a bending force that can resist the repulsive force of the Kunoshijin layer itself at the stepping part, which puts extra load on the wearer's feet. I felt fatigued and lost the feeling of wearing them. In addition, the midsole is made up of layers of different types and colors, and especially when a sponge layer with low hardness and good cushioning properties is layered to reduce weight, the outer wall surface of that layer is exposed as it is. Because of this, compressive strain is large, and in addition, the fatigue is severe, and the cushioning properties decrease significantly over a short period of time, impairing the feeling of wearing, and the poor shape retention promotes lateral vibration, deteriorating driving functionality. I was letting it happen.

(c) Purpose of the Invention In view of the current situation, the present invention combines a polyester urethane outer layer foam and a resilient inner layer foam to improve the breaking strength of the polyester urethane outer layer foam. It effectively takes advantage of its elastic properties, low compression set, and good recovery power, as well as the cushioning properties and lightness of the resilient inner foam.
The object of the present invention is to provide a midsole with excellent shape retention and moldability, and excellent running functionality.

(D) Structure of the Invention The present invention comprises at least two polymer foam layers layered between the outsole and the cover, and the polymer foam layer has a contour that approximately follows the outsole. , an elastic inner layer foam is covered with a polyester urethane outer layer foam,
The inner layer foam is suitably divided and joined into each part, and is made of a material suitable for each part and a hardness suitable for each part.

(E) Function The midsole of the present invention has the above-mentioned structure, by using a combination of materials having different hardnesses for the polyester urethane outer layer foam and the elastic inner layer foam, respectively.
A smooth hardness difference is created between each part. The hardness of the outer layer foam is in the range of 30 to 80 degrees as indicated by the Asker hardness tester type C value (the same applies hereinafter), the hardness of the inner layer foam is in the range of 20 to 60 degrees, and the average specific gravity of the inner layer foam is 0. .05～
0.30, average specific gravity of outer layer foam is 0.20~0°60
range is used. Weight reduction can be achieved by selecting and combining members from this range to reduce the hardness of appropriate parts such as the stepping part and the central part. This midsole is layered between the outsole and the toe cover, and its lower surface is formed to follow the contour of the upper surface of the outsole, and the upper surface is formed to follow the lower surface contour of the toe cover. Examples of the inner layer foam include foams of polyolefin resins such as polyethylene, ethylene-vinyl acetate copolymer (EVA), rubber, and mixtures thereof. The polyester urethane foam of the outer layer foam is made of 4,4-diphenylmethane diisocyanate, 4
．． Diisocyanates such as 4'-dicyclohexylmetadiisocyanate, glycols such as enalene glycol and 1,4-hexanediol, adipate-based polyethylene adipate, poly(1,4-butylene adipate), poly(1,6-hexane adipate) This is a urethane foam obtained by reacting polyester diols such as

(f) Example Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 shows the midsole of the first embodiment, tal is a plan view, [bl is a longitudinal sectional view, Fig. 4 is a modified version of Fig. 1, tg+ is a plan view, and (hl is a longitudinal sectional view). be.

The inner foam layer (1) of the midsole shown in FIG. 1 has a shape that is almost similar to the outline of the outsole, and is formed to have a thinner thickness at the front and a thicker thickness at the rear. The entire surface of the inner foam layer (1) is covered with the outer foam layer (2) to obtain a midsole with an optimal shape. In this case, the outer layer foam (2) is made of polyester foam polyurethane having a hardness of 50 degrees and an average specific gravity of 0.3 to 0.4. Inner layer foam (1) has an average specific gravity of 0.05 to 0.2
The foamed EVA boards were cut and combined and joined together to create a thicker rear part.
It is divided, and then the heel side thereof is cut into two layers, an upper layer part (6) and a lower layer part (7), and then combined and joined. The hardness of each part is used in an appropriate combination. The hardness is, for example, the tip (5)
20 degrees at the upper part of the heel (6), 35 degrees at the upper part of the heel (7)
The angle is 45 degrees. In addition, as shown in FIG. 4, the structure of the heel is such that a horseshoe-shaped part (8) is formed of the material with the highest hardness on the outside of the tip (9) of the heel, and the inner pushing side of this horseshoe-shaped part Various design changes are possible, such as configuring it so that it protrudes closer to the toe side than the outer leg side. The structure of these inner layer foams (1) can also be applied to the following second and third embodiments. It can also be obtained by cutting an unfoamed EVAM composition into a predetermined shape, pressing and heating it in a mold, and simultaneously molding it into one piece at the same time as foaming. This inner layer foam (1) is layered approximately in the center of the recess corresponding to the midsole formed by combining the upper mold and the lower mold by appropriate means, and the liquid which becomes the outer layer foam (2) is deposited in this recess. The polyurethane material is injected to cause a foaming and curing reaction, and the inner layer foam (1) is transformed into the outer layer foam (2).
) to form a midsole made of polymeric foam that is tightly covered.

By changing the contour of the inner foam layer (1) as necessary, the contour width of the outer layer foam (2) can be freely changed along this contour.

Fig. 2 is a second embodiment of the present invention, fcl is a plan view, (d)
is a longitudinal sectional view thereof. In this embodiment, as shown in FIG. 2, the inner layer foam (1) has a hardness of 25 degrees at its tip (5).
35 degrees at the upper part of the heel (6), 45 degrees at the lower part (7),
The foamed EVA has an average specific gravity of 0.06 to 0.2, and the outer layer foam (2) is polyester foamed polyurethane with a hardness of 50 degrees and an average specific gravity of 0.3 to 0.4, which is almost the same as the first embodiment. Similarly, the inner layer foam (1) is almost entirely covered with the outer layer foam (2), and the outer layer foam (2) on the upper surface of the front part is removed centering on the stepping area, and this removed portion is covered with the inner layer foam (2). (1) is formed so that the inner layer foam (1) directly appears on the surface.

Only the front upper surface of the inner layer foam (1) is held so as to be in contact with the inner surface of the upper mold, and liquid polyurethane material that will become the outer layer foam (2) is injected into the recess formed by combining the upper mold and the lower mold. Then, a foaming and curing reaction is carried out to form a midsole which is a polymeric foam.

FIG. 3 shows a third embodiment of the present invention, in which f8) is a plan view and ffl is a longitudinal sectional view thereof. In this embodiment, as shown in FIG. 3, the inner layer foam (1) has a hardness of 25 degrees at the tip (5), a hardness of 35 degrees at the tip (9) of the heel, and a horseshoe-shaped portion (
8) Foamed EVA with a temperature of 45 degrees and an average specific gravity of 0.06 to 0°2
However, the outer layer foam (2) has a hardness of 55 degrees and an average specific gravity of 0.4 to 0.
．． Polyester foam bowl urethane No. 5 is used, and the first
Almost the same as in the example, the inner layer foam (1) is the outer layer foam (2).
) is formed by coating. In this example, the inner layer foam (
An appropriate number of protrusions (3) are provided on both sides of the stepping part and the outer side of the heel, and the outer push side end surface of these protrusions (3) is attached to the contoured end surface of the outer layer foam (2). In addition, a concave curved portion (4) is provided from the inner side of the heel of the inner layer foam (1) toward the center from the arch of the heel, and the outer layer is formed to match this curved portion (4). The contour width of the foam (2) is made larger than the other contour widths.An appropriate number of protrusions (3
) is further extended, and the extended portion of this protrusion (3) is fitted and held in a holding hole that communicates with the recess formed by the mold assembly of the upper mold and the lower mold, and the outer layer foam (2) is held. A liquid polyurethane material is injected to cause a foaming and hardening reaction, and after demolding, the extended portion of the protrusion (3) is cut out along the contour end surface.
The end surface of the protrusion (3) of the inner foam layer (1) forms a midsole consisting of a polymer foam layer with the end surface of the protrusion (3) exposed on the contour end surface. In this example as well, the outer layer foam (2) on the front upper surface including the protrusion (3) around the stepping part and the upper surface of the heel protrusion (3) is removed, and this removed portion is replaced by the inner layer foam (2). 1) can be formed so that the inner layer foam (1) is directly exposed to the surface. The color tone of the protrusion (3) may be matched to the color tone of the inner layer foam (1), or simply the protrusion (3) or its outer end face is colored red, blue, yellow, or the like.

Further, the shape of the outer end surface of the protrusion (3) is formed into an appropriate shape such as a circle, a triangle, or a rhombus depending on its function.

As described above, the mid-sole in Example 1 consists of covering and bonding the entire surface of the inner layer foam (1) made of foamed EVA similar to the bottom shape with the outer layer foam (2) made of polyester foam polyurethane. The disadvantages of foamed EVA are that it has no breaking strength and can be damaged by a slight external force, and polyester-based foamed polyurethane, especially low-foamed polyurethane, has the disadvantage of not being lightweight and causing sink marks in thick parts such as the heel. This effectively brings out the advantages of foamed EVA's cushioning properties and light weight, as well as the high breaking strength, low compression set, and good recovery power of polyester foam polyurethane. I was able to do that. If the thickness of the stepping part of the outer foam layer (2) is made thin, the flexibility can be increased and the bending resistance to the foot of the wearer can be alleviated.Also, the thickness of the heel part of the inner layer foam (1) can be made thinner. Even if the inner foam layer (1) is thicker, it is covered and bonded with the outer foam layer (2), which has a higher hardness than the inner foam layer (1), so it is lightweight, has rich cushioning properties, and exhibits effects with less lateral vibration. The structure is such that the thick heel part of the inner foam (1) is enclosed and covered by a thin layer of the outer foam (2), so it is lightweight without causing sink marks. It has the effect of mitigating and absorbing the impact when landing on a heavy foot.Furthermore, the inner layer foam (1) has a tip portion (5), an upper layer portion (6) of the heel portion (or tip portion (9)), and a heel portion. The inner layer foam (1) is divided into the lower layer (7) (or horseshoe-shaped portion (8)) and the hardness of these parts increases in sequence, and the inner layer foam (1) is divided into the outer layer foam (1) with a higher hardness. Since it is covered by the body (2), the hardness on this upper surface decreases from the contour toward the center, or from the inner heel pushing side to the outer leg side and further toward the tip, and the change in hardness changes smoothly. , it significantly improves the feeling of wearing without causing discomfort such as unevenness on the foot of the wearer, and furthermore, as shown in Fig. 4, the movement of pressure at the time of landing is reduced to the outside leg side of the heel. It was possible to smoothly move the heel from the external pushing arch to the internal pushing side, and to prevent the heel from rolling too much into the internal pushing side, that is, overpronation.

The midsole in the second embodiment is based on the effects of the first embodiment, and the inner layer foam (1
) The free foamed EVA exposed on the upper surface mainly compresses and stretches, thereby absorbing and relaxing the bending and stretching force acting on the stepping part, reducing the bending and stretching resistance force on the wearer's feet, and drastically reducing fatigue.

The midsole in the third embodiment can further enhance the running functionality of the midsole in the first embodiment.

As mentioned above, the foamed E material, which has a lower hardness than the outer layer foam (2) made of polyester-based foamed polyurethane, is used at the treading part of the midsole where the bending and stretching action is most intense and at both outer edges thereof.
By replacing the inner layer foam (1) made of VA with an appropriate number of protrusions (3), when the stepping part is bent and stretched, the protrusions (3) of the foam 1; It can be compressed and stretched to alleviate and absorb the bending/stretching force, thereby reducing the bending/stretching resistance force on the wearer's feet and drastically reducing fatigue. In addition, the landing begins almost at the center of the heel, and the stepping movement progresses along the outer leg side from the ball of the lesser heel to the ball of the toga heel, and after the landing is completed, it mainly moves from the 2nd and 3rd foot of the ball of the heel. Since the device moves forward by kicking off the ground, as mentioned above, the heel outward pushing side end of the outer foam layer (2) is connected to the inner layer foam (1), which has a lower hardness than the outer layer foam (2).
By replacing the protrusion (3) with the protrusion (3), when the landing starts from the center of the heel, the protrusion (3) on the outer leg side of the heel is compressed by the stepping pressure, so the movement of the foot is changed from the center of the heel to the heel. It acts as a guide to move the outer leg along the outer leg side, and the outer layer foam (2) has a contour width wider at the inner push side end from the inner heel side to the arch of the foot than the other parts. By doing this, the movement of the foot can be reliably moved towards the tip of the heel along the outer side of the heel, which has more cushioning, so the movement of the footfall can be moved forward along the inner side of the heel. We were able to avoid injuries to the ankle and other parts that would otherwise occur. Further, protrusions (3) of the inner layer foam (1) are exposed on both side end surfaces of the stepping part and on the end surface on the outer leg side of the heel, and these protrusions (3) are formed in a desired color and an appropriate shape. Because of this, it becomes a strong accent and can improve the beauty and give a good impression.

(G) Effects of the Invention The midsole of the present invention is comprised of at least two polymeric foam layers installed between the outsole and the sleeve, and the polymeric foam layer has a contour that roughly follows the outsole. , an elastic inner foam layer is covered with an outer layer foam made of polyester-based urethane that has a harder hardness than the inner foam layer, and the inner layer foam is appropriately divided into sections and joined together using a material suitable for each section. The inner layer foam has excellent cushioning properties and light weight, and the outer layer foam has excellent breaking strength and low compression set. The synergistic effect of both flexibility and good recovery power is achieved, and the desired structure can be adjusted by changing the outer contour width of the bending part and heel part or the thickness of each partial layer of the inner foam. As a result, running functions such as flexibility, cushioning properties, running stability, landing surface %l relaxation, and prevention of adduction can be improved, and these optimal effects can be exhibited.

In addition, the midsole of the present invention is made by dividing and joining the inner layer foam into each part and making the material and hardness suitable for each part, so the outer layer is foamed by appropriately selecting the optimal hardness and material for each part. It is possible to create a smoother hardness difference between each part of the body, including the body, and it also makes use of the characteristics of different materials to provide excellent wearability and improve running performance and running functionality. I can do it.

[Brief explanation of the drawing]

FIG. 1 shows a first embodiment of the present invention (al is a plan view, (bl is a plan view,
2 is a longitudinal sectional view of the same, FIG. 2 is a second embodiment, +a is a plan view,
+d+ is a vertical sectional view, Figure 3 is the third embodiment (81 is a plan view, (f) is a side view, Figure 4 is a modified version of Figure 1, fgl is a plan view, and (h) is a It is a vertical cross-sectional view of the same. 1. Inner layer foam, 2. Outer layer foam, 3. Protrusion, 4
...Curved portion, 5.. Tip portion, 6.. Upper layer portion, 7.. Lower layer portion, 8.. Horseshoe-shaped portion, (9).. Tip portion of heel portion. Patent applicant: Tsukisei Kasei Co., Ltd. Figure 1 Figure 2 Figure 3 (e) -1 to m- 111, -1 Figure 4

Claims (1)

[Claims] 1. Consisting of at least two polymer foam layers installed between the outsole and the cover, the polymer foam layer has a contour that approximately follows the outsole, and has elasticity. A midsole characterized in that an inner foam layer with elasticity is covered with an outer foam layer of polyester-based urethane, and the inner foam layer is suitably divided and bonded into each section and has a hardness suitable for each section. 2. The hardness of the inner layer foam is 20 on the Asker hardness tester C type.
~60 degrees, and the hardness of the outer foam is 30 to 80 for the same C type.
The hardness of the outer foam layer is higher than the hardness of the inner foam layer, and the hardness of the inner foam layer is higher than the hardness of the toe portion, the lower layer of the heel, or the tip of the heel, and the upper layer of the heel. 2. A midsole according to claim 1, in which the midsole is in a sequentially elevated relationship to the section or horseshoe section. 3. The mid-sole according to claims 1 and 2, wherein the upper surface of the outer layer foam corresponding to the treading area is cut out, and only the treading area is a two-layer polymer foam layer. 4. A cutout is provided on both sides of the stepping portion of the outer foam layer and/or on the outer heel side of the heel, and the cutout is made of a polymeric foam layer filled with the inner foam layer. The midsole according to Items 1 and 2. 5. The midsole according to claims 1 and 2, which has a polymeric foam layer in which the outer foam layer has a larger contour width from the inside of the heel to the foot of the foot and is combined with the inner foam layer.