JPH0655857B2 - Rubber composition for shoe soles - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rubber composition for shoe soles.

(Prior Art) Conventionally, as a rubber composition for shoe soles having high wear resistance, a rubber compound in which carbon black is added as a filler (A), and a rubber compound filled with a silane coupling agent It is known that white carbon is added as an agent (B). However, in the case of the mixture of (A) and (B), the hardness (hardness according to JIS K6301 spring type hardness test A type ... simply referred to as hardness hereinafter) must be set to about 80, and the flexibility and anti-slip property as a shoe sole It deteriorates and the motor function is lost, and since carbon black is added as a filler in the A composition, the obtained shoe sole cannot be colored other than black which is a color unique to carbon black,
In compounding B, even if the hardness was set to around 80, sufficient abrasion resistance could not be imparted.

(Problems to be Solved by the Invention) The present invention is flexible, flexible, anti-slip, stretchable,
It is intended to provide a shoe sole having excellent tear strength and abrasion resistance and a good exercise function.

(Means for Solving Problems) The present invention relates to 5 to 25 parts by weight of a polynorbornene polymer, 10 to 70 parts by weight of a mineral oil softener, and 100% by weight of a diene rubber, and a white filler as a filler. Carbon 4
Rubber for soles characterized by having a hardness of 55 to 75 according to JIS K6301 spring hardness test A type after crosslinking by adding 0 to 60 parts by weight, an appropriate amount of a coloring agent and a commonly used rubber compounding chemical. The composition is the subject matter of the invention.

In the present invention, as the diene rubber, for example, one kind or a mixture of two or more kinds of natural rubber, styrene butadiene rubber, polybutadiene rubber, polyisoprene rubber, acrylonitrile butadiene rubber and the like is used.

The polynorbornene polymer used in the present invention has a molecular weight of 2 obtained by synthesizing norbornene from ethylene and cyclopentadiene by the Diels-Under reaction and ring-opening polymerization of this norbornene monomer.
By polymerizing 100 to 350 parts by weight of a mineral oil-based softener with 100 parts by weight or more of a polymer, it exhibits good rubber-like properties and, in addition, 2 in the main chain.
Since it has a heavy bond, it can be cross-linked with a normal cross-linking agent such as sulfur and organic peroxide, and has excellent wear resistance and tensile strength even at medium hardness (hardness 55 to 75 according to JIS K6301).
It shows the tear strength.

In the present invention, the compounding weight ratio of the polynorbornene polymer to the diene rubber is set to the diene rubber 10
The amount of 5 to 25 parts by weight relative to 0 parts by weight is that if the compounding weight ratio of the polynorbornene polymer is less than that, the wear resistance of the rubber shoe sole at medium hardness cannot be sufficiently improved, and more than that. In that case, the dispersibility in the diene rubber is deteriorated, and the workability such as kneading and forming the dough is deteriorated. In the present invention, aromatic oils, naphthene oils, paraffin oils, etc. are used as the mineral oil softener.

In the present invention, the blending weight ratio of the mineral oil-based softening agent is limited to 10 to 70 parts by weight with respect to 100 parts by weight of the diene rubber, as long as the blending amount of the mineral oil-based softening agent is less than that. The hardness of the obtained sole becomes too high, flexibility,
If the slip resistance is reduced and the content of the mineral oil-based softening agent is more than that, the hardness of the obtained shoe sole becomes too low, the rebound resilience of the obtained shoe sole decreases, and the shoe sole has a bad burr. In addition, after molding the shoe sole, there is a drawback that bleeding is caused by the leaching of the softening agent from the inside of the shoe sole.

In the present invention, as the white carbon as a filler, silicic acid anhydride (silica), hydrous calcium silicate, hydrous aluminum silicate or the like is used, and the compounding weight ratio thereof is 40 parts by weight with respect to 100 parts by weight of diene rubber. ~
The limitation to 60 parts by weight is that if the blending weight ratio of white carbon is less than that, the tensile strength of the obtained sole,
If the reinforcing strength such as tear strength and abrasion resistance decreases, and if the blending weight ratio of white carbon is more than that, the dispersibility in rubber deteriorates, and the workability such as kneading and dough spreading decreases, and Tensile strength, tear strength, wear resistance of the soles are deteriorated, and the reinforcement and flexibility of the soles,
This is because the slip resistance is reduced.

In the present invention, various kinds of coloring agents such as inorganic pigments and organic pigments are used.

As other commonly used rubber compounding chemicals used in the present invention, a plasticizer, a cross-linking agent, a cross-linking accelerator, an anti-aging agent, and if necessary, a foaming agent, a foaming aid and the like are appropriately added and compounded.

In the present invention, the hardness of the rubber composition for shoe soles after cross-linking is limited to 55 to 75 because when the hardness is lower than that, the wear resistance decreases, and when the hardness is higher than that, flexibility, This is because the slip resistance is reduced.

The ingredients prepared as above are the Banbury mixer,
The mixture is kneaded and kneaded by a kneading roll or the like, and the sheeting dough is discharged, and if necessary, cut into pellets or ribbons, and molded into shoe soles by press molding, injection molding or the like.

Example 1 A rubber compound having the composition shown in the upper part of Table 1 in Tables 1 to 3 was taken out to a thickness of 5 mm with a Banbury mixer, weighed and filled in a mold, and a press gauge pressure of 100 kg / 100 kg / 160 ° C. for 12 minutes. hardness 65 and sole by press molding in cm ^2, hardness 65 molded comparative example Likewise this
The bottom of Table 1 shows a comparison between the sole and the tensile strength, tear strength, and wear resistance.

(Effects and Effects) As is clear from the comparative test results shown in the lower part of Table 1, the shoe soles obtained in Examples 1, 2 and 3 have higher tensile strength and tear strength than the shoe soles obtained in Comparative Examples. The abrasion resistance can be remarkably improved, and the hardness of the sole obtained by the rubber composition of the present invention is limited to the medium hardness of 55 to 75, so that the flexibility and the slip resistance are excellent and the exercise function is excellent. There is. Moreover, since white carbon is used as the filler, it can be freely colored by appropriately selecting the colorant as necessary.

Claims (1)

[Claims] 1. 100 parts by weight of a diene rubber, 5 to 25 parts by weight of a polynorbornene polymer, 10 to 70 parts by weight of a mineral oil softening agent, and white carbon 4 as a filler.
Rubber for soles characterized by having a hardness of 55 to 75 according to JIS K6301 spring hardness test A type after crosslinking by adding 0 to 60 parts by weight, an appropriate amount of a coloring agent and a commonly used rubber compounding chemical. Composition.