JPH11137307A - Outsole for footwear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high antislip property and high strength on a wet foothold by compounding a silylating agent which bonds to silica but does not bond to a polymer and a silane coupling agent which bonds to both. SOLUTION: The silylating agent which has bondability to the silica but does not have bondability to the polymer is compounded with a rubber compsn., by which the water repellency of the silylating agent acts effectively on the compd. and an water repellent property is imparted to the compsn. The silane coupling agent having the bondability to both of the silica and the polymer together with the silica is compounded with the rubber compsn., by which the silica and polymer i.e., fillers for reinforcement, are connected via the silane coupling agent and the strength of the rubber compsn. is effectively enhanced. When a user moves on the wet foothold, the outsoles enhanced in the strength come into contact with an adequate contact pressure without the significant deformation in the state of loading the outside with the human body weight. Simultaneously the outsoles allow the water of the foothold to escape outside and is capable of creating large friction resistance with the foothold. The extremely good antislip property is achieved by the friction resistance coupled with the water repellent property by the silylating agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outsole (shoe sole) for footwear, and more particularly to an outsole for a footwear, which can provide excellent anti-slip properties (grip properties) even on a wet scaffold.

[0002]

2. Description of the Related Art In footwear such as shoes and sandals, in order to obtain good comfort and safety, an outsole (sole), which is the bottom of the footwear, has excellent anti-slip properties (grip properties) with respect to the scaffold. It is important to have In the footwear outsole made of the rubber composition, when the scaffold is in a dry state, a rubber-specific gripping force can be obtained with respect to the scaffold, and excellent anti-slip properties (grip properties) can be obtained.

[0003]

However, on a scaffold in a wet state such as on a rainy day or a waterside, a sufficient coefficient of friction between the sole surface and the scaffold cannot be obtained, and excellent anti-slip property can be obtained. Disappears. This is because when the scaffold is wet, a water film is interposed between the sole surface and the scaffold, and the water film reduces the coefficient of friction between the sole surface and the scaffold.

[0004] The present invention has been made in view of the above circumstances, and is an outsole made of a rubber composition,
It is an object of the present invention to provide an outsole for footwear which has extremely good anti-slip properties even on a wet scaffold and has a necessary strength as an outsole.

[0005]

In order to solve the above-mentioned problems, the present invention provides an outsole for footwear formed by molding a vulcanized rubber composition, wherein the vulcanized rubber composition contains silica and a polymer together with silica. By blending a silane coupling agent that has a binding property to both and a silylating agent that has a binding property to silica but has no binding property to a polymer, it is required for high anti-slip property and outsole on a wet scaffold. This achieves both high strength.

In the above outsole for footwear of the present invention,
By incorporating a silane coupling agent having a binding property to both silica and a polymer together with silica, the reinforcing filler silica and the polymer are connected via the silane coupling agent, thereby increasing the strength of the rubber composition. While being effectively enhanced, by having a silylating agent that has binding properties with silica but has no binding properties with the polymer,
The water repellency of the silylating agent effectively acts to impart excellent water repellency to the rubber composition. In addition, when wearing footwear using an outsole that has been strengthened by a silane coupling agent and exercising on a wet scaffold, the outsole will have a moderate contact pressure without significant deformation under the weight of a human being At the same time as contacting the scaffold, the water of the scaffold can escape to the outside, and a large frictional resistance can be obtained between the scaffold and the water repellency of the silylating agent.

That is, the silane coupling agent is
Although it itself has water repellency and acts to improve the water repellency of the rubber composition, it forms a chemical bond with both the silica and the polymer in the rubber composition. ). On the other hand, since the silylating agent binds only to silica, the reinforcing effect of the rubber composition is small, but the water repellency of the rubber composition itself greatly improves the water repellency of the rubber composition.

Among the silane coupling agents having a binding property to both silica and a polymer, those commercially available as silane coupling agents include (a) one S
a reactive group (e.g., -C), which is a compound having an i element and which undergoes hydrolysis to become a silanol group and forms a siloxane bond between the Si element in the compound and the Si element of silica.
l, -OR, -NR, -OR ₁ OR ₂ where R, R
₁ , R ₂ is a methyl group or an ethyl group. ) Is the above 1
One or two bonded to two Si elements and having a functional group (eg, vinyl group, epoxy group, amide group, mercapto group, halogen atom) which reacts with a polymer (rubber component) at the terminal. A compound in which an organic group is bonded to one Si element, or (b) three alkoxy groups having a polysulfide bond in a molecule represented by the following general formula (Chemical Formula 1) and bonding to the Si element at both ends. Compounds with groups can be used.

In the compound (b), the polysulfide group causes an active sulfur release reaction, a vulcanization reaction, and a disproportionation reaction, and finally forms a bond between the silane and the polymer, while the Si element Are hydrolyzed into silanol groups and form siloxane bonds with the Si element of silica in the same manner as described above. Since the formation rate of the siloxane bond between the silica and the Si element is much faster than the release reaction, the vulcanization reaction and the disproportionation reaction of the active sulfur of the polysulfide group, this compound (b) When silica is blended, first, the silica surface becomes hydrophobic, the viscosity of the unvulcanized rubber is reduced, and the dispersibility of silica in the polymer is also improved.

Embedded image (Wherein, n represents an integer of 1 to 4, m and k represent 1 to 6
Represents an integer. )

[0010] These specific examples are shown in Tables 1 and 2 below.

[Table 1]

[0011]

[Table 2]

The silylating agent having a binding property to the silica but not to the polymer is a compound having one Si element, which is hydrolyzed to be a silanol group, A reactive group that forms a siloxane bond between the element and the Si element of silica (eg, -Cl,
-OR, -NR, -OR ₁ OR ₂ where R, R ₁ ,
R ₂ is a methyl group or an ethyl group. ) Is bonded to the one Si element by one to three, and an alkyl group or a phenyl group having 1 to 10 carbon atoms is 1 to one Si element.
Compounds having up to three bonds can be used. The alkyl group or phenyl group here does not react with the polymer (rubber component).

The specific examples are shown in Tables 3 and 4 below.

[Table 3]

[0014]

[Table 4]

In addition to the above-mentioned compounds, hexamethyldisilazane [(CH ₃ ) ₃ SiN
HSi (CH ₃ ) ₃ ], N, O- (bistrimethylsilyl) acetamide [(CH ₃ ) ₃ SiOC (CH ₃ ) N
Si (CH ₃ ) ₃ ] and N, N-bis (trimethylsilyl) urea {[(CH ₃ ) ₃ SiNH] CO}.

At least one part of these compounds is free from bonding with silica or a polymer and exists in a free state, so that the rubber composition has extremely high water repellency.

The silane coupling agent and the silylating agent are blended together with silica in a rubber composition. Silica is used in an amount of 30 to 8 based on 100 parts by weight of the polymer component of the rubber composition.
0 parts by weight, preferably 40 to 70 parts by weight. This depends on the amount of the silane coupling agent, but generally when the amount of silica is less than 30 parts by weight with respect to 100 parts by weight of the polymer, the reinforcing effect of the rubber composition (outsole) is difficult to obtain, and 80 parts by weight. If the number is larger than this, the outsole becomes too hard, the workability is reduced, and the material cost is increased.

The silane coupling agent is used in an amount of 1 to 15 parts by weight, preferably 3 parts by weight, per 100 parts by weight of the polymer component.
-10 parts by weight. This depends on the amount of silica, but if it is less than 1 part by weight per 100 parts by weight of the polymer, it is difficult to form a strong bonding force between the polymer in the rubber composition and the silica to be dispersed. As a result, durability such as abrasion resistance and cut resistance deteriorates due to insufficient strength of the rubber composition, and deformation of the outsole under load becomes too large, and contact pressure to the ground is dispersed, and a stable grip is obtained. It becomes difficult to gain strength. On the other hand, if the amount is more than 15 parts by weight with respect to 100 parts by weight of the polymer, an extra silane wrap ring agent is deposited on the surface of the outsole, and the degree of crosslinking in the outsole becomes too large to deform the outsole. Instead, the gripping force on the ground tends to decrease, and the material cost increases, which is not preferable.

The silylating agent is used in an amount of 1 to 15 parts by weight, preferably 2 to 15 parts by weight, based on 100 parts by weight of the polymer. This depends on the amount of the silane coupling agent, but generally less than 1 part by weight per 100 parts by weight of the polymer makes it difficult to impart sufficient water repellency to the rubber composition (outsole). If the amount is more than 15 parts by weight, an extra silylating agent is precipitated on the surface of the outsole, causing poor appearance and increasing the material cost.

The type of silica is not particularly limited.
Both dry silica and wet silica (hydrous silica) can be used, but it is preferable to use wet silica (hydrous silica) having good kneading processability. The amount of silica is 30 to 80 parts by weight, preferably 40 to 70 parts by weight, per 100 parts by weight of the polymer component. This is because the amount of silica is 30 parts per 100 parts by weight of the polymer component.
When the amount is less than 10 parts by weight, it becomes difficult to obtain a strong bonding force between silica and the polymer even when the silane coupling agent is blended, and the amount is 80 parts by weight based on 100 parts by weight of the polymer component.
If the amount is more than the weight part, the workability decreases and the sole becomes too hard.

The above-mentioned silica, silane coupling agent and silylating agent are mixed with the rubber component by various mixers together with other components to be compounded in the rubber composition. Since the silane coupling agent and the silylating agent are liquid at room temperature, their dispersibility in rubber is very good.

The rubber component (polymer component) of the rubber composition includes natural rubber, isoprene rubber, butadiene rubber,
Conventional rubbers used for producing outsole for footwear, such as styrene-butadiene rubber, acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber, butyl rubber, acrylic rubber, and urethane rubber Materials can be used. These may use not only one kind but two or more kinds of materials.

A filler other than silica may be added to the rubber composition. For example, when carbon is added, the wear resistance of the outsole is further improved, and the outsole of footwear (shoes) that exercises violently is used. It is suitable. Carbon is usually blended in an amount of 20 parts by weight or more and 100 parts by weight or less based on 100 parts by weight of the polymer component in the rubber composition. This is because when the amount is less than 20 parts by weight, the effect of improving abrasion resistance is hardly exhibited, and when the amount is more than 100 parts by weight, the outsole becomes too hard.

In addition to the silica, the silane coupling agent, the silylating agent, and the like, the rubber composition may be compounded with compounding agents which have been conventionally used for producing this type of outsole. Also in the present invention, the rubber composition is generally vulcanized and molded, and a vulcanizing agent such as sulfur and a vulcanizing aid such as zinc white and stearic acid are blended with the rubber composition.
Further, a vulcanization accelerator can be blended. Further, an anti-aging agent and a softening agent (plasticizer) may be added. The vulcanizing agent is usually added in an amount of about 1 to 3 parts by weight per 100 parts by weight of the polymer component in the rubber composition.

Although the shape of the outsole is not particularly limited, it is preferable to form a protrusion for increasing the contact area with the road surface and a groove for improving drainage on the ground contact surface.
The size, height, shape, and number of the protrusions, the shape, depth, and number of the grooves are appropriately determined. In addition, it is preferable that the entire outsole is formed of a molded article of the rubber composition containing the silica, the silane coupling agent, and the silylating agent,
The outsole may be composed of a molded product of a rubber composition partially containing the silica, the silane coupling agent, and the silylating agent. For example, only the heel portion on the ground contact surface of the outsole or only the sole portion extending from the toe to the back may be formed of a molded article of a rubber composition containing the above silica, silane coupling agent, and silylating agent. .

The outsole of the present invention is particularly suitable for the outsole of sports shoes such as tennis shoes and golf shoes and shoes for shogging.
It is also suitable as an outsole for footwear used in water places such as fishing boots, flip flops, diving shoes, motorcycle shoes, trekking shoes, bath shoes, rain shoes and the like. Of course, it goes without saying that the present invention is also effective when applied to outsole of footwear other than these.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. Example 1 A kneaded material having the formulation shown in the upper part of Table 5 below was prepared, and each kneaded material was placed in a mold for an outsole and vulcanized and formed at 160 ° C. for 10 minutes.
6 and Comparative Examples 1 to 3 were produced. In addition, the shape of the ground surface of these outsole was the shape shown in FIG. That is, the outsole 100 includes a first sole portion 51 that supports the sole of the foot from the toe of the foot, a second sole portion 52 that supports the heel portion of the foot, and the first sole portion 51.
And an arch part 53 connecting the second sole part 52.

The ground surface of the first sole portion 51 has a width of 2.5
The narrow grooves 11A and 11B having a width of 5.5 mm and the thick grooves 13 having a width of 5.5 mm are formed.
23, 24, 25 and 26 are defined. In addition, the narrow groove 1
1A is a single-step groove having a groove depth of 2.5 mm, and a narrow groove 11B.
Is a two-step groove in which an extra-fine groove having a depth of 1.5 mm is further formed in a groove having a groove depth of 2.5 mm. The depth of the large groove 13 is 4
mm. Partition areas 21, 22, 23, 24, 25,
26, a flat portion 30 is left around the periphery, and the uneven portions 21A, 22A, 23A, 24A, 25 of the hen reborn pattern are formed.
A and 26A. Hen reborn pattern uneven part 2
1A, 22A, 23A, 24A, and 25A respectively run their wave patterns substantially parallel to the outer periphery of the sole. On the other hand, the uneven portion 26A of the hen reborn pattern runs its wave pattern in a direction substantially orthogonal to the longitudinal direction of the sole. Hen reborn pattern irregularities 21A, 22A, 23A, 24A, 2
The unevenness difference between 5A and 36A is 3.5 mm. The narrow groove between the divided area 21 and the divided areas 22 and 23 is
The reason for B is to improve the followability of the sole when the toe is bent. Also, the divided areas 24 and 25
And three divisions (narrow grooves 11A, 11B,
The reason why the thick groove 13) is formed continuously is to prevent the sole from bending forward and backward at this portion during walking and running, thereby applying a load to the sole. In addition, the division area 26
A narrow groove 11A having a groove depth of 2.5 mm is formed at the end of the arch 53 on the side of the arch 53, and the flat end portion 28 is divided from the other portions of the partitioned area 26.

The second sole portion 52 has a V-shaped edge cut on the side of the arch 53, and the entire surface of the second sole portion 52 is formed as a concavo-convex portion 27 having a flat shape on the outer periphery of the sole. 27 is 3.5 mm. In the vicinity of the edge of the second sole portion 52 on the arch portion 53 side, a narrow groove 11A having a groove depth of 2.5 mm is formed along the edge.
Are formed, and the end flat portion 29 is divided from other portions of the second sole portion.

The arch part 53 is composed of the first sole part 51 and the second sole part 51.
It is a concave flat portion that is provided between the sole portions 52 and is concave at a depth of 2.5 mm, and increases the flexibility of the sole.

[Table 5]

In the table, NR is natural rubber RSS3, BR
Is butadiene rubber (BR11 made by Nippon Synthetic Rubber), SBR
Is styrene butadiene rubber (SBR15 made by Japan Synthetic Rubber)
02), silica is wet silica (Ultrasil VN3)
(Manufactured by Degussa)), the silane coupling agent is Si69 (manufactured by Degussa), the silylating agent is KBM 3063 (manufactured by Shin-Etsu Chemical Co., Ltd.), zinc white is silver mine (manufactured by Toho Zinc), and the plasticizer is process oil PW380 (Idemitsu Kosan. Antioxidant: Nocrack 200 (Ouchi Shinko Chemical Co., Ltd.), sulfur: powdered sulfur (Tsurumi Chemical), vulcanization accelerator (1): Noxeller N
S (manufactured by Ouchi Shinko Chemical), vulcanization accelerator (2) is Noxeller EZ (manufactured by Ouchi Shinko Chemical), and vulcanization accelerator (3) is soscinol D (manufactured by Sumitomo Chemical). The chemical name of silane coupling is bis (3-triethoxysilylpropyl) tetrasulfene. The chemical name of the silylating agent is hexyltrimethoxysilane. The amounts in the table are parts by weight.

(Evaluation of grip (slip resistance)) As shown in FIG. 1, the outsole 1 of each of Examples 1 to 6 and Comparative Examples 1 to 3 prepared above, and the shoe of the shoe body 2 prepared separately Bonded to the bottom to make a tennis shoe.

For each of the shoes produced above, 10 testers walk, run, and exercise lightly on two types of ground, wet concrete and asphalt, to achieve the best grip (slip resistance) of 5. The scores were evaluated on a scale of 1 to 5 points, and the average value of 10 testers was compared. The results are shown in the middle of Table 5.

(Evaluation of Tear Strength) Separately from the above, the kneaded materials of the respective formulations of Examples 1 to 6 and Comparative Examples 1 to 3 were placed in a test piece mold and heated at 160 ° C. for 10 minutes. A sheet having a thickness of 2 mm is formed by sulfuric acid molding, and the sheet is cut out to form a sheet B
The test piece was evaluated by a tear test method specified in JIS-K-6301. The results are shown in the lower part of Table 5.

As shown in Table 5, together with the silicas of Examples 1 to 6, a silane coupling agent having a binding property to both silica and a polymer, and a silyl compound having a binding property to the silica but having no binding property to the polymer. The outsole molded from the vulcanized rubber composition containing the agent has a tear strength of 40-5.
The strength was high in the range of 0 kgf / cm. The grip performance was a favorable evaluation result of 3.1 or more in both wet asphalt and concrete.

On the other hand, the outsole of Comparative Example 1, in which neither the silane coupling agent nor the silylating agent was blended, had a tear strength of 35 kgf / cm and was insufficient in strength, and the strength was insufficient. In addition, since no water repellency was imparted by the silylating agent, good grip properties were not obtained, and the grip points were extremely poor at evaluation points of 1.6 (asphalt) and 1.4 (concrete). Further, the outsole of Comparative Example 2 in which a silylating agent was blended with silica obtained high grip properties by achieving high water repellency by the silylating agent, but the rubber composition had low strength and low tensile strength. Is low.

The outsole of Comparative Example 3, in which a silylating agent was blended with silica, had a tear strength of 50 and sufficient strength, but did not have good grip properties due to insufficient water repellency. The grip property was poor at the evaluation points of 2.2 (asphalt) and 1.7 (concrete).

[0038]

As apparent from the above description, according to the outsole for footwear of the present invention, a silane coupling agent having a binding property to both silica and a polymer, and a silane coupling agent having a binding property to silica but having a polymer By combining a silylating agent having no binding property, silica as a reinforcing filler and a polymer are connected via a silane coupling agent to effectively increase the strength of the rubber composition, while the silylating agent is The water repellency of the outsole effectively acts, and as a result, when the footwear using the outsole is mounted, extremely good anti-slip property and high strength required for the outsole can be obtained even on a wet scaffold.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of tennis shoes to which an outsole of the present invention is applied.

FIG. 2 is a plan view of a ground contact surface of the outsole of the embodiment.

[Explanation of symbols]

 1 Outsole 2 Shoe body

Claims (2)

[Claims] 1. An outsole for footwear obtained by molding a vulcanized rubber composition, wherein the vulcanized rubber composition contains a silica and a silane coupling agent having a binding property to both silica and a polymer together with silica. An outsole for footwear, comprising a silylating agent having binding property but not binding property to a polymer. 2. The vulcanized rubber composition contains 30 to 80 parts by weight of silica based on 100 parts by weight of the polymer component and 1 to 15 parts by weight of a silane coupling agent based on 100 parts by weight of the polymer component. , A silylating agent with polymer 100
The footwear outsole according to claim 1, wherein the content is 1 to 15 parts by weight relative to parts by weight.