JP2001211905A - Sole and shoes - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide soles 1 which are light in weight and are nevertheless excellent in strength and durability and shoes using the same. SOLUTION: The soles 1 consist of crosslinked rubber moldings. The shoes 1 contain small-diameter carbon black of 10 to 40 nm in particle diameter. The compounding ratio of the small-diameter carbon black is 10 to 40 parts per 100 parts base material rubber. The soles 1 do not contain a softener at all or even when the soles contain the softener, the compounding ratio thereof is as small as <=3 parts per 100 parts base material rubber. The soles 1 do not contain air bubbles. The sp.gr. of the soles 1 is 0.900 to 1.10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to shoe soles such as tennis shoes, jogging shoes, trekking shoes, men's shoes and the like, and more particularly to shoe soles formed of a crosslinked rubber molded article. The present invention also relates to a shoe provided with the sole.

[0002]

2. Description of the Related Art Shoes are composed of soles, uppers, insoles and the like. Of these, the soles are usually made of rubber. This sole is the part that receives the weight of the wearer,
In addition, it is necessary to have a high strength because it is a portion where a load accompanying the exercise is applied. From the viewpoint of improving the strength, a rubber composition in which a filler such as carbon black or silica is blended in a base rubber is often used for shoe soles (for example, Japanese Patent Publication No. 8-32799, Japanese Patent No. 2915349). Gazette).

However, since these fillers generally have a higher specific gravity than the base rubber, the compounding of the filler makes the shoe sole heavier. In a shoe with a heavy sole, the weight of the shoe also increases, which makes the shoe uncomfortable for the wearer. Also, as the mass of the shoe increases, the wearer's legs tend to be more tired.

[0004] In order to reduce the weight of the sole, the sole is sometimes made to contain air bubbles (for example, Japanese Patent Laid-Open No. 2-1).
49206). The bubbles are obtained by foaming a foaming agent, blending micro hollow spheres (also referred to as “micro balloons”) and the like. However, the presence of these bubbles may reduce the wear resistance of the shoe sole. Since the shoe sole is a part that rubs directly with the ground, there is a problem that the shoe sole is worn out early due to a decrease in abrasion resistance (durability is reduced). In addition, the sole of the shoe is often mixed with a softening agent such as oil for the purpose of improving workability, flexibility and the like, and the blending of this softening agent promotes a decrease in wear resistance of the sole. In some cases, the strength may be reduced.

[0005] By reducing the thickness of the sole, the weight of the sole can be reduced. However, the durability of the shoe sole is also reduced by thinning. Also, due to processing and design issues,
There is a limit to thinning.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an object of the present invention is to provide a shoe sole and shoes which are lightweight and have excellent strength and durability.

[0007]

Means for Solving the Problems An invention made to achieve this object is to provide a crosslinked rubber molded article containing no air bubbles, and to apply carbon black having a particle diameter of 10 nm or more and 40 nm or less to 100 parts of the base rubber. 10 parts or more and 40 parts or less, and the compounding amount of the softener is 3 parts or less based on 100 parts of the base rubber, and the specific gravity is 0.900 or more and 1.10 or more.
The sole is set to 0 or less.

[0008] Since the shoe sole does not contain air bubbles, it has excellent wear resistance. In addition, since the compounding amount of carbon black as a filler is as small as 10 parts or more and 40 parts or less, the specific gravity of the shoe sole is reduced to 0.900 or more and 1.100 or less, and the weight of the shoe provided with the shoe sole is reduced. Is done. In addition, since the particle diameter of the carbon black is as small as 10 nm or more and 40 nm or less, the strength of the shoe sole can be maintained even if the compounding amount is small. Furthermore, since the compounding amount of the softener is as small as 3 parts or less based on 100 parts of the base rubber, the strength of the shoe sole can be maintained even if the compounding amount of the filler is small. In addition, in this specification, the numerical value shown by "part" means a ratio based on mass.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Embodiments of the present invention will be described.

FIG. 1 is a sectional view showing a shoe sole 1 according to one embodiment of the present invention. The shoe sole 1 is formed by molding and crosslinking a rubber composition. Although not shown, a shoe is formed by attaching an upper or the like to the shoe sole 1.

The sole 1 does not contain air bubbles, and is therefore excellent in abrasion resistance. Therefore, even if the lower surface of the shoe sole 1 rubs against the ground, it is not easily worn. Here, the air bubbles mean those actively provided by, for example, foaming of a chemical foaming agent or blending of minute hollow spheres. That is, the "cross-linked rubber molded body containing no air bubbles" used in the present specification includes a small amount of air bubbles as defects due to a gas which is unintentionally mixed or generated in a kneading step of the rubber composition, a molding step, etc. (So-called porosity) is also included.

The shoe sole 1 contains, as a filler, carbon black having a particle diameter of 10 nm or more and 40 nm or less (hereinafter also referred to as "small diameter carbon black"). The compounding amount of the small-diameter carbon black is 10 parts or more and 40 parts or less based on 100 parts of the base rubber, which is smaller than the compounding amount of the filler in the ordinary shoe sole 1. The specific gravity of the small-diameter carbon black is about 1.8, which is considerably larger than the specific gravity of a normal base rubber. By reducing the amount of the small diameter carbon black, the weight of the shoe sole 1 is reduced. Specifically, the specific gravity of the sole 1 is set to 1.100 or less. Although the specific gravity is preferably as small as possible, the normally obtained shoe sole 1 containing no air bubbles has a specific gravity of 0.900 or more.

If the amount of the small-diameter carbon black is less than 10 parts, the strength of the shoe sole 1 may be reduced. Conversely, if the amount of the small diameter carbon black exceeds 40 parts, the specific gravity of the shoe sole 1 may increase. From these viewpoints, the amount of the small-diameter carbon black is preferably from 20 parts to 35 parts.

As the particle diameter of the carbon black is smaller, the strength of the sole 1 is improved. Specifically, the particle diameter is preferably 40 nm or less. Thereby, even if the compounding amount of the filler is suppressed, the shoe sole 1 is given sufficient strength. From the viewpoint of strength, the smaller the particle diameter, the better. However, from the viewpoint of economy and workability, the particle diameter is 10 nm or more. The particle diameter of the carbon black is more preferably 10 nm or more and 35 nm or less, particularly 10 nm or more and 2 nm or less.
5 nm or less.

Specific examples of suitable carbon black include Super Ab having a particle diameter of 11 nm to 19 nm as measured according to "ASTM D1765".
ratio Furnace (SAF), Intermediate with particle diameter of 20 to 25 nm
Super Abrasion Furnace (I
SAF), Hi with a particle diameter of 26 nm to 30 nm
gh AbrasionFurnace (HAF).

A filler other than small-diameter carbon black (hereinafter also referred to as "other filler"), such as silica, calcium carbonate, or carbon black having a particle diameter of more than 40 nm, may be used in combination with the small-diameter carbon black. Good.
However, when the specific gravity of the shoe sole 1 is reduced while other fillers are used in combination, the amount of the small-diameter carbon black necessarily decreases, and this may cause a decrease in the strength of the shoe sole 1. The compounding amount of the filler is kept to the minimum necessary. Specifically, the compounding amount of the other filler is the base rubber 1
It is preferably 10 parts or less, particularly preferably 5 parts or less with respect to 00 parts. When the small-diameter carbon black and the other filler are used in combination, the total compounding amount thereof is from 10 parts to 40 parts, particularly 20 parts, based on 100 parts of the base rubber from the viewpoint of weight reduction of the sole 1. Not less than 35 parts by weight.

That is, preferable examples of the filler in the sole 1 are as follows: (1) Small-diameter carbon black is compounded, no other filler is mixed, and the amount of the small-diameter carbon black is adjusted to the base material. 10 for 100 parts of rubber
To 40 parts (particularly 20 parts to 35 parts) and (2) a small diameter carbon black and another filler are compounded, and the total compounding amount of both is 100%
10 parts to 40 parts (particularly 20 parts to 3 parts)
5 parts or less), and the content of the other filler is
In some cases, the amount is 10 parts or less (particularly 5 parts or less) relative to 0 parts.

The sole 1 is not blended with a softener at all, or even if it is blended, the amount thereof is small.
Specifically, the compounding amount of the softener is 3 parts or less based on 100 parts of the base rubber. By setting the blending amount of the softener to be small (or zero), the strength of the shoe sole 1 is maintained even if the blending amount of the filler is small. In addition, the softener is usually blended for the purpose of imparting flexibility and improving workability. However, since the amount of the filler is small in the shoe sole 1, the flexibility is maintained even when the amount of the softener is suppressed, Also, the workability is good. Examples of the softener include oils such as paraffin oil, naphthenic oil, and aromatic oil, and plasticizers such as dioctyl phthalate, dibutyl phthalate, dioctyl sepate, and dioctyl adipate.

The base rubber used for the sole 1 is not particularly limited, and includes, for example, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, butyl rubber, acrylonitrile-butadiene rubber, chloroprene rubber, ethylene-propylene-diene rubber, Acrylic rubber, epichlorohydrin rubber, polysulfide rubber, urethane rubber and the like can be mentioned. These base rubbers may be used alone,
Further, two or more kinds may be used in combination.

A preferred base rubber is high cis butadiene rubber. High cis butadiene rubber is
The rubber contains 90% or more of cis 1,4 bonds, 0% to 3% of 1,2 bonds, and the remaining component is trans 1,4 bonds. By blending the high cis butadiene rubber, the wear resistance of the shoe sole 1 is improved. From the viewpoint of improving abrasion resistance, a high cis butadiene rubber containing 95% or more of cis 1,4 bonds is particularly preferable.

When high cis butadiene rubber is used as the base rubber, the proportion of high cis butadiene rubber in the total base rubber is preferably from 30% by weight to 95% by weight, and more preferably from 40% by weight to 95% by weight. Particularly preferred. If the ratio is less than the above range, the abrasion resistance of the shoe sole 1 may be insufficient. Conversely, if the ratio exceeds the above range, the strength may be slightly reduced.

Other preferred base rubbers include vinyl cis butadiene rubber. Vinyl cis butadiene rubber is a rubber containing 5% to 20% of 1,2 bonds (vinyl), 0% to 3% of trans 1,4 bonds, and the remaining component being cis 1,4 bonds. This vinyl cis butadiene rubber contains a crystalline portion and is excellent in strength (for example, tensile strength). By using the vinyl cis-butadiene rubber, the strength of the shoe sole 1 is maintained even if the amount of the filler is reduced. In addition, the addition of the vinyl cis-butadiene rubber improves the strength of the shoe sole 1 while maintaining good wear resistance. From the viewpoint of strength and abrasion resistance, vinyl cis butadiene rubber containing 1,2 bonds of 10% or more and 20% or less is particularly preferable.

When vinyl cis butadiene rubber is used as the base rubber, the proportion of the vinyl cis butadiene rubber in the total base rubber is preferably from 5% by weight to 70% by weight, more preferably from 5% by weight to 60% by weight. Particularly preferred. If the ratio is less than the above range, the strength of the shoe sole 1 may be insufficient. Conversely, if the ratio exceeds the above range, the abrasion resistance may be insufficient.

Still another base rubber preferably used is 1,2-butadiene rubber. The 1,2-butadiene rubber is a rubber that contains 90% or more of 1,2 bonds and a residual component is a cis 1,4 bond or a trans 1,4 bond, and is also referred to as a resin-based polymer. 1,
By using 2-butadiene rubber, the strength of the shoe sole 1 is improved. In particular, in the shoe sole 1 in which high cis butadiene rubber is used for the purpose of improving wear resistance, the use of 1,2-butadiene rubber further improves the wear resistance and strength of the shoe sole 1 at the same time. obtain.

When both high cis butadiene rubber and 1,2-butadiene rubber are used, the ratio of the total amount of both to the base rubber is preferably 5% by mass to 100% by mass, and more preferably 10% by mass to 100% by mass. It is particularly preferably at most 30% by mass, more preferably at least 30% by mass and at most 100% by mass. When the ratio is within the above range, the strength and wear resistance of the shoe sole 1 are further improved. From the viewpoint of achieving both abrasion resistance and strength, the mass ratio (A / B) of the high cis butadiene rubber (A) to the 1,2-butadiene rubber (B) is preferably 10/90 or more and 95/5 or less. It is particularly preferably from 20/80 to 90/10 and more preferably from 30/70 to 90.
/ 10 or less is more preferable. When the mass ratio is less than the above range, the wear resistance of the shoe sole 1 may be reduced. Conversely, if the mass ratio exceeds the above range, the strength of the shoe sole 1 may decrease.

Still another base rubber suitably used is a high styrene rubber. High styrene rubber is a styrene-butadiene rubber having a styrene content of 60% or more, and is also referred to as a resin-based polymer.
The styrene content of commonly available high styrene rubber is:
60% to 90%. By using the high styrene rubber, the strength of the shoe sole 1 is improved. In particular, in the shoe sole 1 in which high cis butadiene rubber is used for the purpose of improving abrasion resistance, the use of high styrene rubber further improves the abrasion resistance and strength of the shoe sole 1 at the same time.

When both high cis butadiene rubber and high styrene rubber are used, the ratio of the total amount of both to the base rubber is preferably 5% by mass to 100% by mass, and more preferably 10% by mass to 100% by mass. Is particularly preferred,
The content is more preferably from 30% by mass to 100% by mass. When the ratio is within the above range, the strength and wear resistance of the shoe sole 1 are further improved. Further, from the viewpoint of achieving both abrasion resistance and strength, the mass ratio (A / C) of the high cis butadiene rubber (A) to the high styrene rubber (C) is preferably 10/90 or more and 95/5 or less. / 80 or more and 90/10
The following is particularly preferable, and 30/70 or more and 90/10 or less are more preferable. When the mass ratio is less than the above range, the wear resistance of the shoe sole 1 may be reduced. Conversely, if the mass ratio exceeds the above range, the strength of the shoe sole 1 may decrease.

[0028] Three kinds of base rubbers of high cis butadiene rubber, 1,2-butadiene rubber and high styrene rubber may be used in combination. In this case, the ratio of the total amount of these three types to the base rubber is preferably 5% by mass to 100% by mass, particularly preferably 10% by mass to 100% by mass, and more preferably 30% by mass to 100% by mass. More preferred. Further, from the viewpoint of achieving both abrasion resistance and strength, the total amount of the high cis butadiene rubber (A), the 1,2-butadiene rubber (B) and the high styrene rubber (C) (B + C)
And the mass ratio (A / (B + C)) is 10/90 or more and 95 /
5 or less is preferable, 20/80 or more and 90/10 or less are especially preferable, and 30/70 or more and 90/10 or less are more preferable.

From the viewpoint of reducing the weight of the sole 1, the specific gravity of the base rubber used is preferably as small as possible. Specifically, a base rubber having a specific gravity of 0.940 or less, particularly 0.910 or less, is preferably used. When the low specific gravity base rubber and another base rubber are used in combination, the ratio of the low specific gravity base rubber to the total base rubber is preferably 40% by mass or more, particularly preferably 50% by mass or more. . The specific gravity of the low specific gravity base rubber is preferably as small as described above, but the specific gravity of the base rubber usually obtained is 0.850 or more.

The cross-linking form of the shoe sole 1 is not particularly limited, and for example, sulfur cross-linking, peroxide cross-linking and the like can be applied.
The sole 1 may contain a suitable amount of a silylating agent, a silane coupling agent, an antioxidant, a vulcanization accelerator, a crosslinking aid, a coloring agent, and the like, if necessary.

Although the sole 1 is a single layer, the shoe may have two types of soles, for example, a midsole and an outsole. In this case, the outsole is the sole of the present invention.

[0032]

EXAMPLES Hereinafter, the effects of the present invention will be clarified based on examples, but it should be understood that the present invention should not be construed as being limited based on the description of the examples.

Example 1 An isoprene rubber having a specific gravity of 0.91 (trade name “Nippol IR-2” manufactured by Zeon Corporation)
200 ") 40 parts, specific gravity 0.91 and cis 1,4
High cis butadiene rubber having a bond content of 96% to 98% (trade name “BR-18” of Nippon Synthetic Rubber Co., Ltd.) 60
Part, SAF carbon black having an average particle diameter of 19 nm (Mitsubishi Kasei's trade name “Diablack A”) 30
Part, silane coupling agent (trade name “Si6
9 ") 5 parts, 2,6-di-tert as anti-aging agent
2 parts of -butyl-4-methylphenol (trade name "Nocrack 200" of Ouchi Shinko Chemical Co., Ltd.) and other anti-aging agent (trade name of "Sunnoc N" of Ouchi Shinko Chemical Co., Ltd.)
3 parts, Zinhua No. 1 2 parts, stearic acid 2 parts, sulfur 1.5
Part, N-tert-butyl-2-benzothiazolylsulfenamide (trade name "Noxeller NS" of Ouchi Shinko Chemical Co., Ltd.) as a vulcanization accelerator, diethyl dithiocarbamine as another vulcanization accelerator 0.4 parts of zinc acid (trade name "Noxeller EZ" of Ouchi Shinko Chemical Industry Co., Ltd.) and di-o-tolylguanidine as another vulcanization accelerator (trade name of "Noxeller DT" by Ouchi Shinko Chemical Co., Ltd.) ")
0.2 part was kneaded with an internal kneader to obtain a rubber composition.
This rubber composition was put into a mold and pressed and heated at 160 ° C. for 10 minutes to obtain a shoe sole of Example 1. The shape of this shoe sole is as shown in FIG.

Example 2 and Comparative Example 1 The same procedure as in Example 1 was carried out except that paraffin oil (trade name “PW380” of Idemitsu Kosan Co., Ltd.) was added in the amount shown in Table 1 below. 2 and Comparative Example 1 were obtained.

[Comparative Example 2] The blending amount of carbon black was 50 parts, and 2 parts of microballoons (trade name “EXPANCEL DU80” of Nippon Philite Co.) whose outer shell was made of vinylidene chloride-acrylonitrile copolymer were blended. The sole of Comparative Example 2 was obtained in the same manner as in Example 1 except for the above.

Comparative Example 3 Except that 30 parts of GPF carbon black having an average particle diameter of 62 nm (trade name “SEIST V” manufactured by Tokai Carbon Co.) was blended in place of carbon black having an average particle diameter of 19 nm, In the same manner as in Example 1, the shoe sole of Comparative Example 3 was obtained.

Example 3 Instead of isoprene rubber, a vinyl cis butadiene rubber having a specific gravity of 0.91, containing 17% of 1,2 bonds and 1% of trans 1,4 bonds (available from Ube Industries, Ltd.) 25 parts of trade name "VCR617") and 15 parts of 1,2-butadiene rubber having a specific gravity of 0.909 and containing at least 93% of 1,2 bonds (trade name "RB830" of Nippon Synthetic Rubber Co., Ltd.) The sole of Example 3 was obtained in the same manner as in Example 1 except that the amount of carbon black was changed to 25 parts.

Example 4 The compounding amount of isoprene rubber was 2
5 parts, the compounding amount of the high cis butadiene rubber was 65 parts, and the specific gravity was 1.05 and the styrene content was 85 parts.
% Of high styrene rubber (trade name "Nippol 2007J" of Zeon Corporation) was blended in the same manner as in Example 1 to obtain a shoe sole of Example 4.

Example 5 The compounding amount of isoprene rubber was 1
0 parts, 20 parts of vinyl cis butadiene rubber (the above-mentioned trade name “VCR617”) and 10 parts of 1,2-butadiene rubber (the above-mentioned trade name “RB830”) were mixed, and the compounding amount of carbon black was 35 parts. The sole of Example 5 was obtained in the same manner as Example 1 except for the above.

Comparative Example 4 The amount of the high cis butadiene rubber was 35 parts, and the specific gravity was 1.
Example 1 except that 65 parts of chloroprene rubber (neoprene WRT, trade name of Showa Dupont Co., Ltd.), which is 23 parts, was blended.
In the same manner as in the above, a shoe sole of Comparative Example 4 was obtained.

[Measurement of Specific Gravity] A block-shaped test piece was cut out from the sole of the shoe and its specific gravity was measured. The results are shown in Table 1 below.

[Measurement of Hardness] The rubber composition used for the shoe sole was put into a mold, and pressurized and heated at 160 ° C. for 15 minutes to obtain a plate-like test piece having a thickness of 12 mm. Using this test piece, with a durometer hardness type A hardness tester,
The hardness was measured according to JIS-K-6253. The results are shown in Table 1 below. In addition, from the viewpoint of stability, flexibility and cushioning properties of the sole, the hardness is 6
0 to 85, particularly 65 to 80, is preferred.

[Measurement of Tensile Strength] The rubber composition used for the shoe sole was put into a mold and pressed and heated at 160 ° C. for 10 minutes to obtain a plate-like molded product having a thickness of 2 mm. This molded body was punched into a JIS-Dumbbell No. 3 shape to obtain a test piece. This test piece was subjected to a tensile test according to JIS-K-6251 to measure the tensile strength. The results are shown in Table 1 below. In addition, the tensile strength is preferably 13 MPa or more, particularly preferably 15 MPa or more from the viewpoint of preventing chipping during use, and the tensile strength is preferably 9 MPa or more from the viewpoint of comfort.
It is preferably 0 MPa or less, particularly preferably 80 MPa or less.

[Measurement of Abrasion Amount] The rubber composition used for the sole of the shoe was put into a mold and pressed and heated at 160 ° C. for 15 minutes to obtain a disc-shaped test piece having a thickness of 12.7 mm. . This test piece was subjected to an Akron abrasion test based on JIS-K-6264 to measure the abrasion capacity. In addition, JIS-K-
In 6264, the wear capacity was measured at 1000 rotations, but this time the wear capacity was measured at 2000 rotations. The results are shown in Table 1 below.

[0045]

[Table 1]

In Table 1, the soles of Comparative Examples 1 to 3 are as follows.
Low tensile strength and high wear. The sole of Comparative Example 4 has a large specific gravity. On the other hand, the sole of each embodiment has a low specific gravity, a high tensile strength, and a small wear amount. From these evaluation results, the superiority of the present invention was confirmed.

[0047]

As described above, the shoe sole of the present invention is lightweight and has excellent strength and durability. In the shoes using the soles, good comfort can be obtained.
Also, these shoes last longer.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a shoe sole according to an embodiment of the present invention.

[Explanation of symbols]

 1 ... Shoe sole

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F050 AA01 AA06 HA38 HA53 HA84 JA04 JA09 4J002 AC011 AC031 AC061 AC071 AC081 AC091 AE052 BB151 BB181 BG041 CH041 CK021 CN021 DA036 EH097 EH147 FD010 FD027 GC00

Claims (2)

[Claims] Claims: 1. A crosslinked rubber molded article containing no air bubbles, containing 10 to 40 parts of carbon black having a particle diameter of 10 to 40 nm based on 100 parts of a base rubber. Is 3 parts or less with respect to 100 parts of the base rubber, and the specific gravity is 0.900 or more and 1.100.
The soles of the following. 2. A shoe provided with the sole according to claim 1.