JPH0718123A - Rubber compound composition - Google Patents

Abstract

PURPOSE:To obtain a rubber compound composition having shock and vibration absorbing actions and useful for forming a grip to be held by hand (e.g. golf club, tennis racket and motorbike), sole of sports shoes and power tool. CONSTITUTION:This rubber compound composition having excellent shock and vibration absorptivity is produced by compounding a rubber composition with microspheres (including crushed particles and short fibers) free from reactive group bonding to rubber on the surface. The average of the maximum diameter of the microsphere (shown in the figures (a), (b) and (c)) is >=10mum, preferably 20-300mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber material for cushioning shocks, such as a rubber for gripping by a hand (golf club, tennis racket, motorcycle) or rubber for soles of athletic shoes, and a rubber material for shielding impact vibration of a power tool. It is a thing that can be used as.

[0002]

2. Description of the Related Art In recent sports equipment, (1) golf clubs and (2) sports shoes have been remarkably reduced in weight. The problem here is to reduce impact vibration. Further, (3) shock vibration of machinery such as power tools used by hand has been a problem for a long time.

(1) When the weight of the golf club is reduced, the shock and vibration absorption is deteriorated. It is found that it is necessary to reduce the grip weight in order to reduce the weight while keeping the overall balance. . For this reason, it has been found that since the rubber thickness used in the grip material is reduced to reduce the weight, the shock and vibration absorption is inevitably deteriorated.

However, in the current state of the art, the lightweight golf club emphasizes the flying property and the grip fitting property, and the improvement of the shock and vibration absorption in the grip is left behind.

Generally, a rubber material which absorbs impact vibrations is heavy and soft, and does not have characteristics as a grip material. . In particular, if the ball is soft and has low supporting rigidity, it will not rotate in a desired direction due to rotation and wobbling. Therefore, a rubber material that is light, hard, has a firm support rigidity, and further absorbs impact vibration is desired as a grip material.

(2) Next, regarding the recent weight reduction of sports shoes, the heaviest part of the shoe is the rubber of the sole, and in order to reduce the weight of the rubber of the sole, the sole of the shoe is reduced. The thickness of the rubber is reduced, so the impact vibration absorption becomes worse.
To remedy this, some manufacturers have air, others have gelled liquids, or soft materials rich in oil, and even fired materials partially in the midsole. It explains that it was incorporated and improved to absorb shock vibration.

It is said that the shock-vibration absorbing material is most effectively used for the entire sole, but the reason for partially using the shock-absorbing material is that the shock-absorbing material is soft and has no supporting rigidity. It is said that if you put it in, the support rigidity will decrease and the sense of unity between the foot and the sole will disappear. In addition, cutting and pasting various functional materials in this way to build a shoe sole increases the number of manufacturing steps and reduces productivity. Therefore, there is a demand for a rubber material which is required to have soles as a single body, is light, hard and has high support rigidity, and absorbs impact vibrations.

(3) Occupational diseases (white wax disease), which are considered to be caused by impact vibration in power tools (Chiangsou) and the like.
There is. It is said that the anti-vibration improvement for this measure is progressing considerably, but it is not said to be sufficient yet. The characteristics required for these are light, hard and high supporting rigidity because they are operated by hand. It is a rubber material that can block impact vibrations.

[0009]

Therefore, the problem to be solved by the present invention is to develop a rubber composition which is light, hard and capable of absorbing shock vibration.

[0010]

[Means for Solving the Problems] As a result of intensive studies, in order to solve the above problems, a rubber compound contains microspheres which do not have a soot reactive group bonded to rubber on the surface, and the size of the microspheres is The means was that the average diameter of the maximum major axis (FIGS. 1a, b, c) was 10 μm or more, preferably in the range of 20 to 300 μm.

[0011]

In general, as a compounding treatment for improving the impact absorption of rubber, a large amount of oil or filler (carbon) is compounded to reduce the crosslink density. This is because it is believed that shock vibration absorption can be improved by increasing the internal loss and making it soft.

The present invention provides a rubber compounding composition which is excellent in shock and vibration absorption by incorporating microspheres having no reactive group for bonding with rubber on the surface thereof into the rubber compounding.

That is, since the microspheres which are not bonded to the rubber contained in the rubber compound are not bonded to the rubber, friction occurs between the rubber and the microspheres during deformation. This friction becomes an internal loss and improves shock vibration absorption. Also, since these microspheres do not act like a plasticizer like oil, they do not reduce rubber hardness like oil.

The size of the microspheres may be 10 μm or more, and more preferably 20 μm-300 μm.
Good in the range of m. The reason is that in the case of a microsphere having a diameter of 10 μm or less, the movement between the rubber and the microsphere during deformation is small, and the loss due to the contact friction with the rubber on the microsphere is small.
This is because if it is 0 μm or more, the contact friction area with the rubber is reduced, so that the internal loss is reduced and the internal loss for absorbing impact vibration is reduced.

Further, the volume occupied by these microspheres which do not bond with the rubber should be 10% or more of the total volume of the rubber compound. If it is 10% or less, sufficient internal loss cannot be obtained and shock vibration is absorbed. Leave a problem with.

By selecting microspheres which do not bind to the rubber and have a small specific gravity, a hard rubber compound composition which is light and has good shock and vibration absorption can be obtained.

Examples of the microspheres having a small specific gravity are "Show Balloon" (trade name of Showa Denko), "Scotch Light." There are hollow ceramics such as glass bubbles' (trade name of 3M company), glass spheres, and as fine spheres having a larger specific gravity than these, solid glass, metal, plastic,
And finely crushed, fine short fibers and the like.

Further, by changing the specific gravity of the microspheres individually or by blending two or more kinds of microspheres having different specific gravities and diameters, a rubber compound composition excellent in absorbing shock vibrations of various specific gravities is used. You can also make things.

The rubber compound composition containing the microspheres does not have a bond between the microspheres and the rubber, resulting in low strength. To compensate for this point, fine nylon short fibers and pulp fibers treated so as to bond with the rubber. Can be mixed and supplemented.

These fine reinforcing fibers are rubbers obtained by graft-bonding nylon short fibers through an initial condensation product of an alkylphenol formaldehyde resin from Ube Industries, Ltd. under the trade names UBEPOL-HE-0200 (natural rubber), HE- 2800 (EPDM), HE-4000
It is sold as (NBR). Also, a product obtained by treating pulp fiber with resorcin-formalin is commercially available from Monsanto under the trade name of Santo Web.

The raw rubber of the present invention is synthetic or natural isoprene rubber, butadiene rubber, EPM, EPD.
M, NBR, butyl rubber, styrene-butadiene rubber,
Urethane rubber, acrylic rubber, epichlorohydrin rubber, silicone, and fluorine rubber can be used. These may be used alone, or two or more kinds may be blended and used.

As compounding materials other than the raw rubber, titanium oxide, zinc oxide, carbon, calcium carbonate, magnesium carbonate, silicic acid compounds, etc. are compounded, and as a vulcanizing agent, sulfur and commonly used thiazole are used. One type or two or more types of vulcanization accelerators such as vulcanization accelerators such as vulcanization accelerators, sulfanamides, guanidines, etc. Not limited to the above-mentioned compounded materials, compounded materials used for compounding general rubber plastics can be appropriately used.

[0023]

EXAMPLE An example in which a grip of a golf club is implemented will be described as an example, but the present invention is not limited to such an example.

The basic compounding ingredients other than the microspheres of the present invention and the number of parts by weight are as follows: natural rubber 67 EPDM 30 (1) HE-02005 (2) stearic acid 1 zinc white 5 accelerator CZ 2 (3) sulfur 1 (NOTE ) (1) UBEPOL-HE-0200 is a natural rubber 100
It is a mixture of 50 parts by weight of finely cut nylon with respect to parts by weight. (Product name, manufactured by Ube Industries, Ltd.) (2) EPDM is EP-33 manufactured by Nippon Synthetic Rubber Co., Ltd.
It was used. (3) NOCCELER CZ (trade name, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.)

The kneading for adjusting the rubber compound is sulfur,
The compounding agent other than the accelerator and the rubber were kneaded with a Banbury mixer, and the sulfur and the accelerator were kneaded with the pre-compounding agent on a roll. The rubber composition prepared as described above was formed into a sheet, cut so as to fit into a mold for a golf club grip, and heated and compressed at 160 ° C. for 10 minutes to prepare a grip.

The impact vibration property was evaluated by using the golf club provided with this grip to evaluate the magnitude of the impact vibration property that comes into the hand when the golf ball is actually hit.

In Example 2, the average of the maximum major diameters of the microspheres not bonded to rubber is 75 μm, and the volume is 5% of the rubber compounding volume.
In the case of, the shock-vibration property is comparable to that of Comparative Example 1 (commercially available product), and the shock-vibration absorption is slightly better than that of Comparative Example 1 when the proportion of the microspheres of Example 3 is 15%. It was considered that 10% or more of the volume of the microspheres contained in the rubber compound is effective in mitigating impact vibration.

In Example 6, the average of the maximum major diameters of the microspheres was 8
When the volume was 30 μm and the volume was 30% of the rubber compounding volume, the level of impact vibration resistance was a little better than that of Comparative Example 1. And in Example 9, the average of the maximum major axis of the microspheres is 350.
When the ratio in μm was 30% in the rubber compounding volume, the impact vibration was at a slightly better level than in Comparative Example 1. From this, it was judged that the range of the average size of the maximum major axis of the microspheres is preferably 10 to 300 μm.

[0028]

Industrial Applicability As described above, the rubber compounding composition of the present invention containing the microspheres that do not bind to the rubber is a rubber material having excellent shock and vibration absorbing properties.

Such a characteristic is obtained by gripping with a hand (golf club, tennis racket, motorcycle), or the bottom of athletic shoes,
And a rubber compound composition which can be used as a rubber material for shielding impact vibration of a power tool. Further, not only the rubber material in the above field but also the shock and vibration shielding material of other industries can be properly used.

[Brief description of drawings]

[0030]

FIG. 1 is a plan view showing typical maximum major axes of various shapes of microspheres. a. ． ． ． ． Plan view of the maximum major axis in the case of short fibers b. ． ． ． ． Plan view of the maximum major axis when the crushed material has irregularities c. ． ． ． ． Plan view of the maximum major axis of a spherical object

[0031]

Claims (2)

[Claims] 1. A shock-vibration-absorbing material comprising microspheres (including pulverized products and short fibrous products) which do not have a reactive group for bonding with rubber on the surface, in an amount of 10% or more of the volume of the rubber compound. It is an excellent rubber composition. 2. The maximum major axis of the microspheres (FIGS. 1a, b, c)
The rubber compound composition according to claim 1, which has an average diameter of 10 μm or more and is excellent in impact vibration absorption.