JP3929427B2 - Anti-slip foam for soles - Google Patents

Description

  The present invention relates to a foam for a shoe sole excellent in wet grip properties and a shoe sole obtained therefrom.

The bottom surface (ground surface) of sports shoes and casual shoes is required to have wet grip properties in rainy weather. In the shoe sole of the shoe, the wet grip property is improved by devising the unevenness (design) of the ground contact surface. However, as the ground contact surface wears, the wet grip property deteriorates with time. A foam of rubber or resin is generally a solid member because the cell wall 2 constituting the cell (cavity) 1 shown in FIG. 4 exhibits a scratching effect and moisture on the floor surface escapes into the cell 1. High wet grip performance. Further, as a prior patent by the present applicant, there is also proposed a shoe sole material in which a crushed product of walnut shell or rice husk is added to a foam, and wet grip properties are further improved by the micro spike effect of the crushed product (for example, , See Patent Document 1). On the other hand, shoe soles have been proposed in which pulverized leather absorbent powder is blended with solid rubber instead of foam to improve water wettability and improve wet grip (for example, Patent Documents). 2).
Japanese Patent No. 3270387 (Claim 1, FIG. 1) Japanese Patent No. 2927591 (Claim 1)

However, a sufficient wet grip performance improvement effect cannot be obtained only with foam cells and cell walls. Further, when the pulverized product of walnut shell or rice husk is added to the foam, the wet grip property is improved, but the tensile strength and the wear resistance are greatly lowered when the added amount of the pulverized product is increased. A shoe sole material having low tensile strength and wear resistance is inferior in durability.
In addition, when a pulverized leather is added to the solid rubber, the wet grip property is improved, but the solid rubber is heavy, so it is not suitable for sports shoes that require light weight.
In addition, pulverized walnut shells, rice husks, or leather are very expensive because the raw material costs are added to the pulverization costs, leading to an increase in the unit price of materials.

  Therefore, an object of the present invention is to provide a foam for a shoe sole that is lightweight and excellent in wet grip properties, is less likely to deteriorate with time, and has excellent durability.

The present invention relates to the following inventions.
1. A rubber and / or shoe soles for foam resin, through a range mesh from 100μm to 3.0mm sieve, rubber shape polishing cutting of leather Ru der flocculent and / or resin 100 A shoe having a cell (cavity) having a size of 120 μm to 3.5 mm in contact with an abrasive cut of leather present in a foam, which is blended in an amount of 0.5 parts by weight or more and less than 10 parts by weight. Bottom foam.
2. A foam for a shoe sole, wherein the leather cut material passes through a sieve opening of 250 μm to 2.5 mm.
3. A foam for a shoe sole, wherein the leather cut material passes through a sieve opening of 350 μm to 2 mm.
4). A shoe sole foam having a cell size of 420 μm to 2.4 mm.
5). A shoe sole obtained by molding the above foam for a shoe sole.

  According to the present invention, by adding a leather cut material having high water absorption to a foam for a shoe sole, the water wettability of the foam is improved, and a thin water film interposed between the shoe sole and a road surface This will weaken the lubricating action and improve wet grip (slip resistance). Further, unlike the conventional case (Patent No. 2927591) in which a pulverized leather is added to solid rubber, the present invention is applied to a foam, so there is no risk of impairing the lightness of shoes and the like.

  In particular, in the present invention, a polished cut product of leather having a cotton shape is added, so that the wettability (adhesiveness) with a matrix of rubber or resin is compared with the case of adding a pulverized leather product having a granular shape. ) Is slightly lower. As a result, when the matrix is foamed, a larger cell than the normal foamed cell is generated around the polished abrasive cut of the leather, so that the water absorption effect of this cell and the micro spike effect of the cell wall further increase the wetness. The grip is improved. In addition, even if the abrasive cuts of leather fall off, the water absorption effect by this large cell and the micro spike effect by the cell wall will continue, and even if the shoe sole wears while wearing shoes, Since a leather cut product appears, stable wet grip is obtained.

In addition, compared with the ground rice husks used in the prior art (Japanese Patent No. 3270387), the leather abrasive cuts are superior in the wettability (adhesiveness) with the rubber or resin matrix. It is possible to suppress a decrease in physical properties due to the addition of substances as much as possible.
Therefore, the shoe sole material of the present invention has achieved the light weight of the shoe by using a foam, has improved wet grip properties, and has sufficient durability required as a shoe sole material. Is.
Furthermore, the leather cut material added to improve wet grip properties can reuse the waste material generated in the leather manufacturing process, making it a lightweight, superior wet grip property and durable shoe sole material. Can be provided at low cost.

  The reason why the wet grip property is improved by the present invention will be described. On the road surface wet with water, a thin water film interposed between the shoe sole made of hydrophobic rubber or resin and the road surface acts as a lubrication, and the wet grip property is lowered. When a hydrophilic leather-polished cut product is added to the foam for a shoe sole, the wettability of water is improved, and the lubricating action of a thin water film interposed between the shoe sole and the road surface is reduced. As a result, wet grip properties can be improved. Moreover, as shown in FIG. 1, since the leather cut material 3 is cotton-like, the wettability (adhesiveness) with the rubber or resin matrix 4 is slightly lowered, and the case is molded into a foam. Then, a large cell 5 is formed in contact with the leather cut material. The cell 5 has an average diameter of about 120 μm to 3.5 mm, and is considerably larger than the other cells 6. Therefore, the micro spike effect by the cell wall 7 around the cell 5 is remarkably improved. Further, as the cell 5 becomes larger, moisture easily escapes into the cell 5, so that the wet grip property is remarkably improved. In addition, as shown in FIG. 2, the effects of these cells 5 and the cell walls 7 can be obtained even after the leather cut material has slipped, so that a rapid decrease in wet grip properties can be suppressed.

  That is, when this foam is used for a shoe sole, even if the shoe sole wears while wearing shoes, hydrophilic abrasive cuts appear one after another from the inside of the foam, so that the wettability of water decreases. The wet grip can be maintained without any problems.

  Most of the leather abrasive cuts of the present invention are cotton-like as shown in FIG. 3, and the size of the sieve opening is in the range of 100 μm to 3.0 mm, preferably in the range of 250 μm to 2.5 mm. More preferably, it is set so as to pass through a range of 350 μm to 2 mm. When the size of the leather cut material to be added exceeds 3.0 mm, the polished cut product is too large, and physical properties such as tensile strength and wear resistance are greatly deteriorated. On the other hand, if the size of the abrasive cut is less than 100 μm, the abrasive cut is too small, so that no large cells are generated around the leather cut and the microspike effect cannot be obtained. Does not improve sufficiently. The sieve according to the present invention uses a metal mesh sieve defined in JIS Z8801-1.

  The leather cut material is added in an amount of 0.5 to 10 parts by weight per 100 parts by weight of the raw rubber and / or resin (100 parts by weight of the raw rubber and / or resin polymer). If the added amount of the leather abrasive cut is less than 0.5 parts by weight, the wet grip property is not sufficiently improved because the effect of improving wettability with water is too small. Moreover, when the addition amount of the leather cut material is 10 parts by weight or more, numerous air holes are generated, and a good foam cannot be molded. In addition, the strength of the foam is significantly reduced. Therefore, in order to obtain adequate strength as a material for a shoe sole while exhibiting sufficient wet grip properties, it is necessary to set the addition amount of the leather cut material to 0.5 parts by weight or more and less than 10 parts by weight. Yes, preferably 1 to 5 parts by weight.

  In the present invention, the reason why the leather cut material is used is that, as shown in FIG. 5, the pulverized leather 8 has a granular shape, so that the wettability (adhesiveness) with the matrix 9 is good, and the leather No large cells are generated around the pulverized product. Therefore, since the micro spike effect and the water absorption effect due to the large cell, which are generated when a leather cut product is added, the effect of improving the wet grip property is reduced.

  In addition, in the present invention, another reason for using a leather cut product is that the seed shell pulverized product such as walnut shell and rice husk has a sag (adhesiveness) to the matrix compared to the leather polished product. This is because it is bad, and if it is added in a large amount, physical properties such as wear resistance are remarkably lowered. On the other hand, the leather cuts are better than the crushed seed husks, so they can be added in a larger amount than the crushed seed husks. This is because the effect of improving wet grip properties is further enhanced.

The leather cut material used in the present invention is not particularly limited. For example, a leather obtained by buffing leather with a polishing machine or a cutting machine can be used. In either method, the desired leather abrasive cut is prepared by treating with a sieve.
As these abrasive cuts, waste materials generated in the leather manufacturing process can be used, so it is much cheaper than purchasing leather pulverized products that are generally manufactured and sold by freeze pulverization. Is possible.

  As the polished leather cuts, natural leather polished cuts such as cow leather, horse leather, pig leather, sheep leather, goat leather, kangaroo leather, deer leather, crocodile leather, snake leather and lizard leather are preferred, but are not limited to this. Is not to be done. The leather cut material of the present invention is made of collagen fibers having water absorbency and thus exhibits hydrophilicity, and most of the shape is cotton-like. Since these shapes are cotton-like, the large cells 5 are generated as described above, and the micro spike effect and wet grip property of the present invention can be significantly improved. It is also possible to use leather such as artificial leather and synthetic leather.

Examples of the rubber and resin constituting the matrix of the present invention include natural rubber, styrene butadiene rubber (SBR), 1,4-polybutadiene, polyisoprene (IR), diene rubber such as nitrile butadiene rubber (NBR), EPDM, In addition to synthetic rubbers such as EPM, resins such as syndiotactic 1,2-polybutadiene and EVA (ethylene-vinyl acetate copolymer) can be used singly or in combination.
In addition, when blending the matrix material, a reinforcing agent, a plasticizer, a crosslinking agent, a crosslinking accelerator, an antiaging agent, a coloring agent, and the like are added as necessary.
In the present invention, when raw material rubber and resin are blended and used, the added amount of the leather cut material is an added amount with respect to 100 parts by weight of the total amount of these raw rubber and resin.

  Hereinafter, the effects of the present invention will be clarified by showing examples and comparative examples of the present invention.

A foam was obtained by adjusting the molding temperature time so that the specific gravity was about 0.70 with the formulation of the matrix shown in Table 1 below. In addition, it shows below about each component of Tables 1-3.
BR: 1,4-polybutadiene (BR01 manufactured by JSR)
IR: Polyisoprene (IR2200 manufactured by JSR)
SBR: Styrene butadiene rubber (JBR SBR1502)
High styrene resin: (POLYSAR HS260 manufactured by Bayer)
Vulcanization accelerator A: N-oxydiethylene-2-benzothiazyl sulfenamide vulcanization accelerator B: Dibenzothiazyl disulfide vulcanization accelerator C: 2-mercaptobenzothiazole vulcanization aid: Organic amine activator A : Antistearic acid aging agent: 2,6-di-t-butyl-4-methylphenol activator B: Zinc oxide reinforcing agent: Hydrous silicate softener: Naphthenic oil blowing agent: N, N-dinitroso pentamethylene・ Tetramine foaming assistant: Urea compound leather polished cut 355 μm to 2 mm: Cow leather is buffed with a polishing machine, and the mesh size of the metal mesh sieve specified in JIS Z8801-1 is in the range of 355 μm to 2 mm. What has passed through Polished cut of leather Less than 100 μm: Buffing of cowhide with a sanding machine and opening of a metal mesh screen as defined in JIS Z8801-1 100 μm passed Leather polishing cut over 3.35 mm: The leather was buffed with a polishing machine, and the mesh opening of the metal screen specified in JIS Z8801-1 did not pass 3.35 mm A pulverized product of leather, average particle size 100 μm: Angren K100P of Daicel Huls Co., Ltd.

Next, results of evaluating the performance of the molded foam shown in Table 1, that is, wet grip properties, tensile strength, and wear resistance will be described.
The wet grip property is that when a sample is placed on a wet iron plate, a weight of 80 kgf is placed on the sample, and the weight is pulled and moved, the maximum static friction coefficient from the initial peak value indicated by the load cell. Asked. The tensile strength is measured by a test according to JIS-K6251, and the wear resistance is an absolute value of a wear volume per 1000 revolutions measured by an Akron wear test method (according to BS903 standard).
In Table 1, the tensile strength and wear resistance suitable as a shoe sole material having wet grip properties and durability suitable for road surfaces wet with water are described as target values.

The following can be seen from the test results in Table 1.
Examples 1-6: It turns out that wet-grip property improves by adding the abrasive cutting material of leather to a matrix compounding. The added amount of the leather cut material is particularly preferably about 1 to 5 parts by weight.

Comparative example

  Next, comparative examples are shown in Tables 2-3. The sample preparation method and the evaluation test method were performed in the same manner as in the above-described examples.

The following can be seen from the comparative examples in Tables 2-3.
Comparative Example 1: The wet grip property is not improved unless a leather cut product is added.
Comparative Example 2: If the added amount of the leather cut material is small, the wet grip property is not improved.
Comparative Example 3: When the added amount of the polished leather cut product is large, the tensile strength and the wear resistance are greatly reduced.
Comparative Example 4: If the grain size of the leather abrasive cut is too small, the cells surrounding the leather abrasive cut will not be large, so that the microspike effect and water absorption effect cannot be obtained sufficiently, improving wet grip properties. The effect is also reduced.
Comparative Example 5: When the grain size of the leather cut material is too large, wet grip properties are improved, but tensile strength and wear resistance are greatly reduced.
Comparative Examples 6 to 8: When the leather pulverized product is added, the cells around the leather pulverized product do not increase, so the micro spike effect cannot be obtained. Below.

  ADVANTAGE OF THE INVENTION According to this invention, the foam for shoes soles which is lightweight and excellent in wet-grip property, and this wet-grip property is hard to deteriorate with time, and was excellent also in durability can be provided at low cost.

It is an expanded sectional view before use of the foam for shoes sole concerning one embodiment of the present invention. It is an expanded sectional view of the state in the middle of wear of the foam for soles of Drawing 1 of the present invention. It is the photograph which image | photographed the grinding | polishing cut material of the cotton-like leather of this invention. It is an expanded sectional view of the conventional foam. It is an expanded sectional view of the foam of a comparative example for explaining the principle of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cell of foam 2 Cell made of shoe bottom of foam 3 Polished leather cut 4 used in the present invention 4 Rubber or resin matrix 5 Large cell made in contact with leather cut 6 Cell 7 of foam Cell wall with micro-spike effect 8 Leather ground 9 Rubber and resin matrix

Claims (5)

A rubber and / or shoe soles for foam resin, through a range mesh from 100μm to 3.0mm sieve, rubber shape polishing cutting of leather Ru der flocculent and / or resin 100 A shoe having a cell (cavity) having a size of 120 μm to 3.5 mm in contact with an abrasive cut of leather present in a foam, which is blended in an amount of 0.5 parts by weight or more and less than 10 parts by weight with respect to parts by weight. Bottom foam.   2. The shoe sole foam according to claim 1, wherein the leather cut material has a sieve opening of 250 μm to 2.5 mm.   The foam for a shoe sole according to claim 2, wherein the leather cut material has a sieve opening of 350 µm to 2 mm.   The foam for a shoe sole according to any one of claims 1 to 3, wherein the cell has a size of 420 µm to 2.4 mm. The shoe sole obtained by shape | molding the foam for shoe soles of any one of Claims 1-4 .

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