JP2005245518A - Outsole and shoe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-weight outsole 8 which is excellent in wear resistance and stability and is easily manufactured. <P>SOLUTION: The outsole 8 is composed of solid rubber, and the outsole 8 is provided with a main body 10 and a projection 12. The projection 12 projectes downwards from the main body 10 and the projection 12 is molded integrally with the main body 10. The projection 12 is composed of a base part 14 and a tip part 16 and the tip part 16 is provided with a grounding surface 18. The specific gravity of the main body 10 and the base part 14 is ≤1.00, and the tip part 16 is composed of a wear-resistant rubber composition. The ratio of the height Ht of the tip part 16 to the height H of the projection 12 is ≥30% and the ratio of the height Hb of the base part 14 to the height H of the projection 12 is ≥10%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to outsole such as golf shoes, tennis shoes, jogging shoes, trekking shoes, and men's shoes.

  The shoe is composed of an outsole, an upper, an insole and the like. The outsole is usually formed from a rubber-based composition. Light shoes are suitable for exercise. The outsole is required to be lightweight. The outsole slides repeatedly with the ground. The outsole also requires wear resistance.

  JP-A-2-149206 discloses an outsole containing bubbles. This outsole is lightweight. However, the wear resistance of the outsole is reduced by the bubbles.

Various soles have been proposed from the viewpoint of achieving both wear resistance and light weight. For example, Japanese Patent Application Laid-Open No. 4-276204 (Japanese Patent Publication No. 7-114721) discloses a sole having a main body made of synthetic leather and a protrusion bonded to the main body. The protrusion is made of a synthetic resin. A sole using synthetic leather is inferior in stability. It takes time to bond the synthetic leather and the synthetic resin.
JP-A-2-149206 JP-A-4-276204

  An object of the present invention is to provide an outsole that is lightweight, excellent in wear resistance and stability, and easy to manufacture.

  The outsole according to the present invention is composed of a polymer composition substantially free of bubbles. The outsole includes a main body and a number of protrusions that are integrally formed with the main body and protrude downward from the main body. The specific gravity of this main body is 1.00 or less. The ratio of the total ground contact area of the protrusions made of the wear-resistant material between the position of 30% of the height from the lower end and the lower end to the total ground contact area of all the protrusions is 30% or more.

  Preferably, a portion between the lower end and a position 30% of the height is made of an abrasion-resistant material, and a specific gravity between the upper end of the height of 10% and the upper end is 1.00 or less. The ratio of the total ground contact area of the protrusions to the total ground contact area of all the protrusions is 30% or more.

The outsole manufacturing method according to the present invention includes:
(1) A step of preparing a mold having a cavity including a reference surface and a recessed portion recessed from the reference surface;
(2) A step of filling at least the lower side of the concave portion with the wear-resistant polymer composition and (3) a step of filling the remaining portion of the cavity with the low specific gravity polymer composition.

  This outsole is excellent in stability because the main body and the protrusion are made of a polymer composition containing no bubbles. Since the main body and the protrusion are integrally formed, this outsole is easy to manufacture. Since the specific gravity of the main body is 1.00 or less, this outsole is lightweight. Since the vicinity of the lower end of the protrusion is made of a wear resistant material, this outsole is excellent in wear resistance.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  FIG. 1 is a partially cutaway front view showing a shoe 2 according to an embodiment of the present invention, and FIG. 2 is a bottom view thereof. The shoe 2 includes an upper 4, a midsole 6 and an outsole 8. Although not shown, this shoe 2 also includes an insole.

  The outsole 8 is made of a rubber composition. By using the rubber composition, flexibility is imparted to the outsole 8. As the base polymer, a synthetic resin may be used together with rubber. When rubber and synthetic resin are used in combination, the proportion of rubber in the total base polymer is preferably 50% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more from the viewpoint of flexibility. 95 mass% or more is particularly preferable. From the viewpoint of flexibility, it is preferable that only rubber is used as the base polymer.

  Preferred rubbers include acrylonitrile-butadiene rubber, VCR, isoprene rubber, styrene-butadiene rubber, butadiene rubber, butyl rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-vinyl acetate copolymer, nitrile-isoprene rubber, chloroprene. Examples are rubber, urethane rubber and natural rubber.

  For the rubber composition, sulfur crosslinking, peroxide crosslinking and the like can be applied. An appropriate amount of a softening agent, a silylating agent, a silane coupling agent, an antiaging agent, a vulcanization accelerator, a crosslinking aid, a coloring agent, or the like is added to the outsole 8 as necessary.

  The outsole 8 does not substantially contain bubbles. In other words, the outsole 8 is made of so-called solid rubber. The outsole 8 made of solid rubber is excellent in wear resistance and stability. In the present invention, the bubbles mean those positively provided by means such as foaming of a chemical foaming agent and blending of fine hollow spheres. The “solid rubber” in the present specification includes those in which a minute amount of bubbles (so-called voids) exist as defects due to a gas that is unintentionally mixed or generated in the kneading process or molding process of the rubber composition. .

  FIG. 3 is an enlarged cross-sectional view showing a part of the outsole 8 of the shoe 2 of FIG. The outsole 8 includes a main body 10 and a protrusion 12. The protrusion 12 protrudes downward from the main body 10. The protrusion 12 is formed integrally with the main body 10. Here, “integral molding” means a state in which the main body 10 and the protrusion 12 are bonded at a molecular level. When the main body 10 and the protrusions 12 are joined via an adhesive, it is not integral molding. Since the main body 10 and the protrusion 12 are integrally formed, the detachment of the protrusion 12 from the main body 10 is suppressed. The integral molding does not require the labor of joining with an adhesive. The protrusion 12 includes a base portion 14 and a tip portion 16. The tip portion 16 includes a grounding surface 18.

  The base portion 14 is made of the same rubber composition as the main body 10. A low specific gravity rubber composition is used for the main body 10 and the base portion 14. The shoe 2 including the main body 10 and the base portion 14 is lightweight. From the viewpoint of light weight, the specific gravity of the main body 10 and the base portion 14 is preferably 1.00 or less, more preferably 0.98 or less, and particularly preferably 0.95 or less. From the viewpoint of strength and stability, the specific gravity is preferably 0.70 or more, more preferably 0.80 or more, and particularly preferably 0.90 or more.

  From the viewpoint of light weight, it is preferable to use a rubber having a specific gravity of 0.95 or less, particularly 0.93 or less as the base rubber of the main body 10 and the base portion 14. Specific examples of preferable rubber include VCR, isoprene rubber and butadiene rubber. VCR is particularly preferable. The VCR is a composite of high cis polybutadiene and highly crystalline syndiotactic polybutadiene. Since the VCR is excellent in strength, the inorganic filler can be reduced by using this VCR. The VCR contributes to the light weight of the outsole 8. From the viewpoint of strength, a VCR having a syndiotactic polybutadiene amount of 10% by mass or more, more preferably 15% by mass or more is preferable. From the viewpoint of wear resistance, a VCR having a syndiotactic polybutadiene content of 20% by mass or less, more preferably 18% by mass or less is preferred.

  In general soles, carbon black or silica is blended as a reinforcing agent. The specific gravity of carbon black and silica is large. In the present invention, from the viewpoint of the light weight of the outsole 8, it is preferable that carbon black and silica are not blended in the main body 10 and the base portion 14 at all. Even when carbon black or silica is blended, the amount is preferably small. Specifically, the total amount of carbon black and silica is preferably 15 parts by mass or less, particularly preferably 10 parts by mass or less with respect to 100 parts by mass of the base rubber.

  It is preferable that a resin reinforcing agent is blended in the main body 10 and the base portion 14. The resin reinforcing agent has a low specific gravity. The amount of carbon black and silica can be reduced by blending the resin reinforcing agent. The resin reinforcing agent contributes to weight reduction of the outsole 8. Specific examples of preferred resin reinforcing agents include syndiotactic 1,2-polybutadiene and high styrene resin. Syndiotactic 1,2-polybutadiene is particularly preferred. A resin reinforcing agent having a specific gravity of 1.05 or less, further 1.00 or less, further 0.95 or less, and further 0.91 or less is particularly preferable.

A rubber composition having excellent wear resistance is used for the tip portion 16. Since the distal end portion 16 is a portion that slides directly on the ground, the shoe 2 lasts longer because the distal end portion 16 is excellent in wear resistance. In the present invention, the “abrasion resistant material” means a material having a wear capacity of 0.30 cm ³ or less measured in accordance with the “A-2 method” of the Akron abrasion test specified in JIS-K-6264. means. In the measurement of the wear capacity, the thickness of the wear wheel is 25 mm, the inclination angle between the test piece and the wear wheel is 15 °, the load applied to the wear wheel is 44.1 N, and the rotation speed of the test piece is 250 rpm. It is said. For the measurement of the wear capacity, a ring-shaped test piece having the same composition as the tip portion 16 and crosslinked under the same conditions as the tip portion 16 is used.

From the viewpoint of wear resistance, the wear volume of the tip 16 is more preferably 0.25 cm ³ or less, 0.20 cm ³ or less is particularly preferred. Wear Volume tip 16 made of a versatile material, 0.01 cm ³ or more, more 0.05 cm ³ or greater and particularly 0.10 cm ³ or more.

  Examples of the base rubber suitable for the tip 16 from the viewpoint of wear resistance include butadiene rubber, isoprene rubber, acrylonitrile-butadiene rubber, VCR, styrene-butadiene rubber, and natural rubber. Abrasion resistance may be improved by improving the crosslinking density, blending a small diameter filler, or the like.

  From the viewpoint of abrasion resistance, it is preferable that carbon black or silica is blended in the tip portion 16. The total amount of carbon black and silica is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, and particularly preferably 25 parts by mass or more with respect to 100 parts by mass of the base rubber. Since the flexibility of the outsole 8 is impaired when the total amount is excessive, the total amount is preferably 50 parts by mass or less.

  The rubber composition of the tip portion 16 is prepared with emphasis on wear resistance. As a general tendency, the specific gravity of a rubber composition excellent in wear resistance is large. From the viewpoint of wear resistance, the specific gravity of the tip 16 is preferably 1.00 or more, more preferably 1.03 or more, and particularly preferably 1.05 or more. Since the ratio of the tip portion 16 to the outsole 8 is small, even if the tip portion 16 has a high specific gravity, there is little adverse effect on the weight of the shoe 2. If the specific gravity of the tip portion 16 is excessive, an adverse effect on the weight of the shoe 2 may occur. In this respect, the specific gravity of the tip portion 16 is preferably 1.20 or less, more preferably 1.15 or less, and particularly preferably 1.10 or less.

As described above, the rubber composition of the main body 10 and the base portion 14 is prepared with an emphasis on low specific gravity. As a result, the main body 10 and the base portion 14 may be inferior in wear resistance. Since the protrusion 12 has a tip portion 16 and it is this tip portion 16 that slides directly on the ground, even if the main body 10 and the base portion 14 are inferior in wear resistance, the initial quality of the outsole 8 is impaired. Absent. From the viewpoint of wear resistance after the shoe 2 has been used for a long time and the tip portion 16 has worn away, the wear capacity of the main body 10 and the base portion 14 is 1.50 cm ³ or less, further 1.00 cm ³ or less, particularly 0 .80 cm ³ or less is preferable.

  In FIG. 3, what is indicated by the double arrow H is the height of the protrusion 12, what is indicated by the double arrow Hb is the height of the base portion 14, and what is indicated by the double arrow Ht This is the height of the tip 16. In the present invention, one having a height H from the main body 10 of 2 mm or more is referred to as a protrusion 12. Usually, the height of the protrusion 12 is 2 mm to 15 mm.

  The ratio of the height Ht of the tip portion 16 to the height H of the protrusion 12 is 30% or more. In other words, the protrusion 12 is made of an abrasion-resistant material between the position at 30% of the height from the lower end and the lower end. From the viewpoint of preventing wear of the tip portion 16, the ratio of the height Ht to the height H is preferably 50%, more preferably 60% or more. This ratio may be 100%. When this ratio is 100%, the base portion 14 does not exist. In other words, the height Hb is zero. Even if the base portion 14 is not present, the light weight of the outsole 8 can be achieved because the main body 10 has a low specific gravity.

  When the base portion 14 does not exist, the boundary between the main body 10 and the protrusion 12 matches the interface between the low specific gravity material and the wear resistant material. At the boundary between the main body 10 and the protrusion 12, stress due to the deformation of the protrusion 12 is concentrated. It is not preferable from the viewpoint of durability of the outsole 8 that the interface between the low specific gravity material and the wear-resistant material matches the stress concentration portion. From the viewpoint of durability, it is preferable that the base portion 14 exists. Specifically, the ratio of the height Hb of the base portion 14 to the height H of the protrusions 12 is preferably 10% or more. In other words, in this protrusion 12, the specific gravity between the position of 10% of the height from the upper end and the upper end is 1.00 or less. The ratio of the height Hb to the height H is preferably 20% or more. From the viewpoint of improving stability due to the low center of gravity of the outsole 8 and the light weight, the ratio is preferably 10% or more, and more preferably 20% or more.

  FIG. 4 is a schematic view showing an example of a method for manufacturing the outsole 8 of FIG. In this manufacturing method, a mold is first prepared. FIG. 4A shows the lower mold 20 of the mold. The mold cavity 22 includes a reference surface 24 and a recessed portion 26. The recessed portion 26 is recessed from the reference surface 24. As shown in FIG. 4A, the recessed portion 26 is filled with the wear-resistant rubber composition A. Next, as shown in FIG. 4B, the plate 28 is lowered. The plate 28 includes a protrusion 30. The protrusion 30 enters the recess 26 and presses the wear-resistant rubber composition A. Next, the plate 28 is raised and the burrs are removed. Next, the cavity 22 is filled with the low specific gravity rubber composition B. Next, as shown in FIG. 4C, the upper mold 32 of the mold is lowered and the low specific gravity rubber composition B is pressed. Next, the rubber compositions A and B are heated through the mold. The rubber causes a crosslinking reaction by heating. The rubber molecules of the wear resistant rubber composition A and the rubber molecules of the low specific gravity rubber composition B are also bonded. In this way, the outsole 8 provided with the main body 10 and the protrusion 12 is obtained.

  The entire recessed portion 26 may be filled with the wear-resistant rubber composition A. In this case, a plate having no protrusion 30 is used. The recessed portion 26 may be filled with a granular or massive wear-resistant rubber composition. In this case, pressing by the plate 28 can be omitted.

  FIG. 5 is a bottom view showing an outsole 34 according to another embodiment of the present invention. The outsole 34 includes a main body 36, a first protrusion 38, and a second protrusion 40. In FIG. 5, for convenience of explanation, the ground contact surface of the first protrusion 38 is painted black. The specific gravity of the main body 36 is 1.00 or less. The first protrusion 38 has a tip portion, like the protrusion 12 shown in FIG. In the first protrusion 38, the space between the position at 30% of the height from the lower end and the lower end is made of an abrasion resistant material. In the first protrusion 38, it is preferable that the specific gravity between the position of 10% of the height from the upper end and the upper end is 1.00 or less. The 2nd protrusion 40 is not provided with the front-end | tip part. The material of the second protrusion 40 is the same as that of the main body 36.

In the outsole 34 shown in FIG. 5, a first protrusion 38 having a tip portion made of a wear-resistant rubber composition and a second protrusion 40 not having a tip portion made of a wear-resistant rubber composition. It is mixed. Even when both are present, the wear resistance of the outsole 34 can be enhanced by the first protrusions 38. From the viewpoint of wear resistance, the ratio P calculated by the following mathematical formula is set to 30% or more.
P = (S1 / (S1 + S2)). 100
S1 in this equation represents the total contact area of the first protrusions 38. S2 in this equation represents the total contact area of the second protrusions 40. From the viewpoint of wear resistance, the ratio P is preferably 50% or more, and more preferably 60% or more. From the viewpoint of productivity of the outsole 34, the ratio P is preferably 90% or less, and more preferably 80% or less.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Preparation of rubber composition]
[Type A]
50.0 parts by mass of acrylonitrile-butadiene rubber (trade name “Nipol DN200” from Nippon Zeon Co., Ltd., specific gravity: 0.98), 50.0 parts by mass of VCR (trade name “UBEPOL VCR617” from Ube Industries, Ltd.) 0.91) 30.0 parts by mass of high styrene resin (trade name “AMERIPOL 1904” by Ameripol Synpol, specific gravity: 1.00), 30.0 parts by weight of SAF carbon black (trade name “Diamond of Mitsubishi Chemical Corporation”) Black A ”, specific gravity: 1.80), 1.0 part by weight of an anti-aging agent (trade name“ Sunnock N ”, Ouchi Shinsei Chemical Co., Ltd., specific gravity: 0.93), 2.0 parts by weight of anti-aging Agent (trade name “NOCRACK 200” from Ouchi Shinsei Chemical Industry Co., Ltd., specific gravity: 1.02), 2.0 parts by mass of zinc oxide (trade name “Zinc Oxide 2” from Toho Zinc Co., Ltd.) : 5.55), 2.0 parts by mass of stearic acid (Nippon Yushi Co., Ltd. trade name “Tubeki bead stearate”, specific gravity: 0.94), 1.0 parts by mass of sulfur (trade name “Tsurumi Chemical Co., Ltd.” Powdered sulfur 200 mesh ", specific gravity: 2.10), 0.1 part by mass of vulcanization accelerator (trade name" Noxeller DT ", specific gravity: 1.18 of Ouchi Shinsei Chemical Industry Co., Ltd.), 1.0 part by mass Vulcanization accelerator (trade name “Noxeller DM” of Ouchi Shinsei Chemical Industry Co., Ltd., specific gravity: 1.50), 0.7 part by weight of vulcanization accelerator (trade name “Noxeller TET of Ouchi Shinsei Chemical Industry Co., Ltd.” ”, Specific gravity: 1.31), and 0.5 part by mass of a vulcanization accelerator (trade name“ Noxeller NS ”of Ouchi Shinsei Chemical Industry Co., Ltd., specific gravity: 1.26) are kneaded with a closed kneader and an open roll. Thus, a type A rubber composition was obtained. The specific gravity of this rubber composition was 1.06, and the wear capacity was 0.20 cm ³ .

[Type B]
60.0 parts by mass of VCR (the above-mentioned “UBEPOL VCR617”), 40.0 parts by mass of isoprene rubber (trade name “Nipol IR2200”, specific gravity: 0.91 by Nippon Zeon Co., Ltd.), 60.0 parts by mass of Shinji Otectic 1,2-polybutadiene (trade name “RB830” of Nippon Synthetic Rubber Co., Ltd., specific gravity: 0.91), 2.0 parts by mass of zinc oxide (the above-mentioned “two types of zinc oxide”), 2.0 parts by mass Stearic acid (previously “bead stearic acid Tsubaki”), 2.0 parts by weight of sulfur (previously “powdered sulfur 200 mesh”), 1.0 part by weight of vulcanization accelerator (previously “Noxeller NS”) , 0.5 parts by mass of a vulcanization accelerator (trade name “Noxeller EZ” of Ouchi Shinsei Chemical Industry Co., Ltd., specific gravity: 1.47) and 0.5 parts by mass of a vulcanization accelerator (the aforementioned “Noxeller DT”) ) Closed kneader and o Kneaded at Punroru to obtain a rubber composition of the type B. The specific gravity of this rubber composition was 0.93, and the wear capacity was 0.80 cm ³ .

[Type C]
Furthermore, a rubber composition of type C was obtained in the same manner as type B except that 3.0 parts by mass of thermally expandable microspheres (trade name “Matsumoto Microsphere F-100” from Matsumoto Yushi Seiyaku Co., Ltd.) was added. It was. The specific gravity of this rubber composition was 0.70, and the wear capacity was 1.55 cm ³ .

[Example 1]
The outsole whose bottom surface was shown in FIG. 5 was manufactured. The outsole includes a main body, a first protrusion whose tip is made of an abrasion-resistant rubber composition, and a second protrusion that does not use the abrasion-resistant rubber composition. The first protrusion includes a base portion and a tip portion. A type B rubber composition is used for the main body, the base portion, and the second protrusion. A type A rubber composition is used at the tip. The ratio of the height Ht of the tip portion to the height H of the first protrusion is 60%. The ground contact area ratio P of the first protrusion is 60%.

[Comparative Example 2 and Example 3]
The outsole of Comparative Example 2 and Example 3 was obtained in the same manner as in Example 1 except that the contact area ratio P of the first protrusion was as shown in Table 1 below. The bottom surface of the outsole of Comparative Example 2 is shown in FIG. 6, and the bottom surface of the outsole of Example 3 is shown in FIG. In FIG. 6 and FIG. 7, the first protrusion is that the ground contact surface is painted black.

[Comparative Example 1 and Examples 2 and 4]
The outsole of Comparative Example 1 and Examples 2 and 4 was obtained in the same manner as in Example 1 except that the height Ht of the tip portion was made as shown in Table 1 below with respect to the height H of the first protrusion. It was.

[Comparative Example 3]
An outsole of Comparative Example 3 was obtained in the same manner as in Example 1 except that the main body and the first protrusion were molded from a type A rubber composition.

[Comparative Example 4]
An outsole of Comparative Example 4 was obtained in the same manner as in Example 1 except that the first protrusion was not provided.

[Comparative Example 5]
An outsole of Comparative Example 5 was obtained in the same manner as in Example 1 except that the main body was molded from a type C rubber composition.

[Comparative Example 6]
An outsole of Comparative Example 6 was obtained in the same manner as in Example 1 except that the first protrusion was not provided and the main body and the second protrusion were molded from a type C rubber composition.

[Evaluation of wear resistance]
An outsole was placed on the ground made of asphalt concrete, a weight of 10 kg was placed on the outsole, and the outsole was dragged. Then, the volume of the outsole at the stage where the distance of 50 cm was reciprocated 100 times was measured, and the difference from the volume before dragging was calculated. The results are shown in Table 1 below.

[Measurement of mass]
A golf shoe was obtained by attaching a midsole and an upper to the outsole. The weight of this golf shoe was measured. The results are shown in Table 1 below.

[sensory evaluation]
The golf shoes were worn by a golfer and walked and hit a golf ball. Then, the stability and lightness were rated in five stages from “1” to “5”. The average score of 10 golfers is shown in Table 1 below.

  As is apparent from Table 1, the outsole of the example is lightweight and has excellent wear resistance and stability. From this evaluation result, the superiority of the present invention is clear.

  The outsole according to the present invention can be applied to various shoes.

FIG. 1 is a partially cutaway front view showing a shoe according to an embodiment of the present invention. FIG. 2 is a bottom view showing the shoe of FIG. FIG. 3 is an enlarged cross-sectional view showing a part of the outsole of the shoe of FIG. 1. FIG. 4 is a schematic view showing an example of a method for manufacturing the outsole of FIG. FIG. 5 is a bottom view illustrating an outsole according to another embodiment of the present invention. 6 is a bottom view showing an outsole according to Comparative Example 2. FIG. FIG. 7 is a bottom view showing the outsole according to the third embodiment of the present invention.

Explanation of symbols

2 ... Shoes 4 ... Upper 6 ... Midsole 8, 34 ... Outsole 10, 36 ... Main body 12 ... Projection 14 ... Base part 16 ... Tip part 18. ..Ground surface 20 ... Lower die 22 ... Cavity 24 ... Reference surface 26 ... Recessed portion 28 ... Plate 30 ... Protruding portion 32 ... Upper die 38 ... First Protrusion 40 ... Second protrusion

Claims (4)

Consisting of a polymer composition substantially free of bubbles,
A main body and a plurality of protrusions that are molded integrally with the main body and project downward from the main body;
The specific gravity of this body is 1.00 or less,
An outsole in which the total ground contact area of protrusions made of wear-resistant material between the position 30% of the height from the lower end and the lower end accounts for 30% or more of the total ground contact area of all protrusions.   A protrusion made of an abrasion-resistant material between the position at 30% of the height from the lower end and the lower end, and a specific gravity between the position of 10% of the height from the upper end and the upper end is 1.00 or less 2. The outsole according to claim 1, wherein a ratio of the total ground contact area to the total ground contact area of all the protrusions is 30% or more. Consisting of a polymer composition substantially free of bubbles,
A main body and a number of protrusions projecting downward from the main body;
The specific gravity of this body is 1.00 or less,
A shoe provided with an outsole in which the ratio of the number of projections made of an abrasion-resistant material to the total number of projections is 30% or more between a position at a height of 30% from the lower end and the lower end. A step of preparing a mold having a cavity including a reference surface and a recessed portion recessed from the reference surface;
Filling at least the lower side of the recessed portion with an abrasion-resistant polymer composition;
A method of manufacturing an outsole, comprising: filling a remaining portion of a cavity with a low specific gravity polymer composition.

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