JPS6264302A - Mid-sole - 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 The present invention relates to a midsole that can enhance running functionality and improve moldability.

In recent years, the soles of footwear have changed to sponge soles in order to reduce the impact on the feet when driving on stone roads, concrete paved roads, etc., and thicker sponge soles are now being worn depending on the function. In such a sole, the outsole is either a solid body or a sponge layer with good wear resistance, and one or an appropriate number of sponge layers with good cushioning properties are inserted between the outsole and the cover. This layer is called 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 cushion layer itself at the stepping part, which places an extra load on the wearer's feet. My feet felt tired and I 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, impairing running functionality. It was making me regress.

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 excellent breaking strength and compression properties of the polyester urethane outer layer foam. By effectively leveraging the advantages of low permanent deformation and good recovery power, as well as the cushioning properties and lightness of the resilient inner layer foam, it has good running functionality with good shape retention and moldability. The purpose of this product is to provide an excellent midsole for customers.

The present invention consists of at least two elastic inner foam layers (1) and an outer foam layer (2) of polyester-based urethane, which are attached between the outsole and the sleeve, and these polymer foams ( 1), (21 has a contour that almost follows the bottom of the bottom,
Notches are provided on both sides of the stepping portion of the outer foam layer (2) and/or on the outer surface of the heel portion, and the protrusions (3) of the inner layer foam (1) are provided in the cutout portions. The object of the present invention is to provide a midsole characterized by being filled, thereby achieving the above object.

The Mitudosol of the present invention has the above-mentioned structure, and the polyester urethane outer layer foam (2) and the elastic inner layer foam (1) are made of materials with different hardnesses in combination. There is a smooth hardness difference between them. The hardness of the outer layer foam (2) is in the range of 25 to 80 degrees as measured by Asker hardness tester C type (the same applies hereafter), and the hardness of the inner layer foam (1) is in the range of 20 to 60 degrees. The foam body (1) used has an average specific gravity of 0.05 to 0.30, and the outer layer foam (2) has an average specific gravity of 0.20 to 0.60. By selecting and combining members from this range, the hardness of appropriate parts such as the stepping part and the central part can be reduced, thereby reducing the weight. This mid-sole is attached between the outsole and the 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 contour of the lower surface of the cover. Examples of the inner layer foam (1) 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 (2) is made of 4.4-diphenylmethane diisocyanate.
Diisocyanates such as 4-dicyclohexylmetadiisocyanate, ethylene glycol.

It is a urethane foam obtained by reacting glycols such as 1.4-hexanediol, and polyester diols such as adihate-based polyethylene adipate, poly(1,4-butylene adipate), and poly(1,6-hexane adipate). .

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view thereof. The inner layer foam +1) is EVA foam with a hardness of 35 degrees and an average specific gravity of o and t~0.15, and the outer layer foam (2) is polyester foam polyurethane with a hardness of 55 degrees and an average specific gravity of 0.4 to 0.5. The inner foam layer (1) is formed by the outer foam layer (2). In this example, an appropriate number of protrusions (3) are provided on both sides of the stepping part of the inner layer foam (1) and on the outer surface of the heel, and the outer end surface of the protrusions (3) is It is formed to match the contour end face of 2). In addition, a concave curved portion (4) is provided from the inner surface of the heel portion of the inner layer foam (1) toward the center of the arch, and the contour width of the outer layer foam (2) is adjusted to match this curved portion (4). Make it larger than other contour widths. An appropriate number of protrusions (3) provided on both sides of the stepping part and the outer surface of the heel of the inner layer foam (1) are further extended, and the extended parts of the protrusions (3) are molded into the upper mold. The liquid polyurethane material that will become the outer layer foam (2) is injected to cause a foaming and hardening reaction, and after removal from the mold, the above-mentioned projection The extended portion of the section (3) is cut off along the contour end surface to form a midsole made of polymeric foam in which the end surface of the protrusion (3) of the inner layer foam (1) is exposed on the contour end surface.

In the present invention, as another embodiment, FIG. 3 (plan view)
As shown in FIG. 4 (longitudinal sectional view thereof), 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. In order to fill this removed portion with the inner layer foam (1), the inner layer foam (1) may be formed directly on the surface. The color tone of this protrusion (3) is
The color tone of the inner layer foam (1) may be matched, or the protrusions (
3) Or only the outer edge is red.

Color it blue, yellow, etc. 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, in the midsole of the present invention, the entire surface of the inner layer foam fil made of foamed EVA similar to the bottom shape or almost the entire surface excluding the upper surface is replaced by the outer layer foam (2) made of polyester foam polyurethane. By covering and bonding with foamed EVA, the disadvantage is that it lacks the breaking strength of foamed EVA and can be damaged by the slightest external force, and polyester-based urethane, especially low-foamed polyurethane, is poor at reducing weight and causes sink marks in thick parts such as the heel. It effectively combines the advantages of foamed EVA, such as cushioning properties and light weight, with the high breaking strength, low compression set, and good recovery power of polyester urethane. I was able to demonstrate this. By reducing the thickness of the stepped portion of the outer foam layer (2), flexibility can be increased and bending resistance to the foot of the wearer can be alleviated. Furthermore, even if the heel part of the inner foam layer (1) is thicker, it is still covered and bonded with the outer foam layer (2) which has a harder hardness than the inner foam layer (1).
When hit lightly, it has a rich cushioning property and exhibits the effect of reducing lateral vibration.Furthermore, in the heel part, the thick heel part of the inner foam layer (1) is enclosed, and this is surrounded by a thin layer of the outer foam layer (2). Because it has a structure covered with , it is lightweight without causing sink marks, and has the effect of cushioning and absorbing the impact when landing. Furthermore, since the inner layer foam (1) is covered with the outer layer foam (2) which has a higher hardness, the hardness on this upper surface decreases from the contour to the center, and the hardness changes smoothly. This significantly improves the comfort of wearing the shoes, without causing discomfort such as unevenness on the feet of employees.

In addition to the above-mentioned effects, the most characteristic effect of the present invention is that the outer layer foam (2) made of polyester-based polyurethane foam is applied to the treading part of the midsole where the bending and stretching action is most severe and its both side edges. An appropriate number of protrusions (3
), when the stepping part is bent and stretched, the foamed EVA protrusion (3) easily compresses and stretches, absorbs the bending and stretching force, and eliminates the bending and stretching resistance force on the employee's foot. Fatigue can be drastically reduced. Also, the landing begins almost at the center of the heel, and the footing moves along the outside from the small gong ball to the 1) L ball, and after the landing is completed, it mainly moves to the toga dance ball and the second ball.
3. Since the person moves forward by kicking the ground with his or her foot, as mentioned above, the outer heel end of the outer layer foam (2) is connected to the inner layer foam (2), which has a lower hardness than the outer layer foam (2). By replacing the protrusion (3) in 1), as soon as the landing starts from the center of the heel, the protrusion (3) on the outside of the heel is compressed by the stepping pressure, so the movement of the step is shifted from the center of the heel. It acts as a guide that moves along the outside of the heel, and the outer layer foam (
2) By making the outline width of the inner edge from the inside of the heel to the arch wider than the outline width of other parts, the movement of the foot is reliably moved along the outside of the heel, which has more cushioning properties, to the tip. On the other hand, the t-t of the ankle, etc. that occurs when the footwork moves forward along the inside of the heel.
n damage could be avoided. Furthermore, the footing portion and the heel portion of the outer layer foam (2) are cut out, and the inner layer foam (1) is cut out.
If the entire upper surface is exposed, the above-mentioned effects will be further promoted, and in addition, the protrusions (3) of the inner layer foam (1) will be exposed on both side end faces and the remote side end face of the treading part. Therefore, if this protrusion (3) is formed in a desired color and in an appropriate shape, it becomes a strong accent 1-, which improves aesthetics and gives a good impression.

The midsole of the present invention is comprised of at least two polymeric foam layers mounted between the outsole and the cover, the polymeric foam layers having a contour that roughly follows the outsole, and an elastic inner layer. Since the foam is covered with an outer layer foam made of polyester-based urethane that has a higher hardness than the inner foam layer, the inner layer foam (1) has the advantages of excellent cushioning properties and light weight, and the outer layer foam The foam (2)'s excellent fracture strength, low compression set, and good recovery power combine to create a synergistic effect, which reduces the outer contour width of the bend and heel. Alternatively, by changing the thickness of each partial layer of the inner foam (1), it is possible to adjust to a desired structure, improving running functions such as flexibility, cushioning, running stability, cushioning landing impact, and preventing internal rotation. In order to achieve these optimal effects, 5. Brief explanation of aspects. Figure 1 is a plan view of one embodiment of the present invention, Figure 2 is a longitudinal sectional view thereof, and Figure 3 is a plane view of another embodiment. FIG. 4 is a longitudinal sectional view thereof.

1- Inner layer foam, 2- Outer layer foam, 3 Projection, 4 Curved portion.

Claims (4)

[Claims] (1) Consisting of at least two elastic inner layer foam (1) and an outer layer foam (2) of polyester-based urethane attached between the outsole and the cover, and these polymer foams ( 1) and (2) have a contour that roughly follows the outsole, and cutouts are provided on both sides of the stepped portion of the outer foam layer (2) and/or on the outer side of the heel. A midsole characterized in that the notch is filled with protrusions (3) of the inner layer foam (1). (2) The inner layer foam (1) is provided with a concave curved portion (4) extending from the inside of the heel to the arch toward the center, and the contour width of the outer layer foam (2) is adjusted to match this curved portion (4). 2. Midsole according to claim 1, characterized in that the width of the contour is larger than the other contour widths, and then the inner foam layer (1) and the outer foam layer (2) are combined. (3) The hardness of the inner layer foam (1) is 20 to 60 degrees on the Asker hardness scale C type, and the hardness of the outer layer foam (2) is 25 to 80 degrees on the same type; Midsole according to claims 1 and 2, comprising polymeric foam layers combined such that hardness is higher than the hardness of the inner foam (1). (4) The outer layer foam (2) is cut out in the stepping portion and the heel portion so that the entire upper surface of the inner layer foam (1) is exposed. Midsole as described.