JP2009091501A - Rubber composition for solid tire and solid tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition for solid tires usable on both of a normal road surface and ice inside a freezer and the like without forming any lug groove reducing productivity. <P>SOLUTION: The rubber composition for solid tires comprises a rubber component and calcium carbonate fine powder. In the rubber composition for solid tires, 5-15 pts.mass calcium carbonate fine powder is mixed to 100 pts.mass of the rubber component. In the calcium carbonate fine powder, the grain size of 50% or more of the total particles ranges 5-150 μm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rubber composition for a solid tire.

  A solid tire is a total rubber tire of an iron core mold used as a tire for a forklift or the like (a no-punk tire manufactured by wrapping rubber around an iron core mold). The specification application includes use on ice such as use in a freezer in addition to use on a normal road surface. For this reason, tires without grooves are used in which lug grooves are formed by hand cut so that traction performance on ice is obtained.

  However, the formation of lug grooves by hand-cutting is a very time-consuming operation, and the productivity has been greatly reduced.

On the other hand, various studless tires designed to obtain traction performance on ice in ordinary passenger cars have been developed, and those using chicken eggshell powder as an additive for such studless tires are known. (Patent Document 1). However, the required performance differs significantly between solid tires and studless tires, and it was considered difficult to improve traction performance on ice using such additives in solid tires. . Moreover, in the studless tire of Patent Document 1, since two or more kinds of eggshell powders having different average particle diameters are used, the control of the particle diameter is complicated and the acquisition itself may be difficult. .
JP 2007-169500 A

  The present invention has been made in view of such a current situation, and the object of the present invention is to be used on both a normal road surface and on ice in a freezer without forming a lug groove that reduces productivity. The object is to provide a rubber composition for a solid tire.

  The present invention is a rubber composition for a solid tire containing a rubber component and finely powdered calcium carbonate, wherein the finely powdered calcium carbonate is blended in an amount of 5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the rubber component. The finely powdered calcium carbonate relates to a rubber composition for a solid tire in which the particle size of 50% or more of all the particles is in the range of 5 to 150 μm.

  Here, the finely powdered calcium carbonate is preferably eggshell powder. The present invention also relates to a solid tire obtained using the rubber composition for a solid tire.

  The rubber composition for a solid tire according to the present invention has the configuration as described above, and can be used on both a normal road surface and on ice in a freezer without forming a lug groove that reduces productivity. Can be provided.

Hereinafter, the present invention will be described in more detail.
<Rubber composition for solid tire>
The rubber composition for a solid tire of the present invention includes a rubber component and fine powder calcium carbonate. The rubber composition for a solid tire of the present invention can contain other components as described below within a range in which the effects of the present invention are exhibited as long as both of them are included.

<Rubber component>
As the rubber component contained in the rubber composition for a solid tire of the present invention, a conventionally known rubber component that can be used for this kind of application can be used without any particular limitation. For example, the following arbitrary diene rubber is used as such a rubber component. That is, natural rubber (NR), polyisoprene rubber (IR), various polybutadiene rubbers (BR), various styrene-butadiene copolymer rubbers (SBR), acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), Diene rubbers such as halogenated butyl rubber and polychloroprene (CR) can be used alone or blended at an arbitrary ratio.

<Fine powdered calcium carbonate>
The finely powdered calcium carbonate contained in the rubber composition for a solid tire of the present invention is blended in an amount of 5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the rubber component, and more preferably the upper limit is 12 parts by mass. Part, its lower limit is 7 parts by mass. When the blending ratio is less than 5 parts by mass, the performance on ice is inferior.

  Such finely powdered calcium carbonate used in the present invention requires that the particle size of particles of 50% or more of the total number of particles is in the range of 5 μm or more and 150 μm or less. More preferably, it is suitable that the particle diameter of particles of 60% or more, more preferably 70% or more of all particles is within the above range.

  When the ratio of those having a particle size of less than 5 μm is increased, the performance on ice is inferior, and when the ratio of those having a particle diameter exceeding 150 μm is increased, the wear resistance is deteriorated. The number of particles and the particle size can be adjusted by various pulverizers, and the particle size and its distribution are measured by using a particle size distribution measuring device (such as SALD-2200 manufactured by Shimadzu Corporation). be able to.

  As such fine powder calcium carbonate, calcium carbonate as a chemical or industrial chemical can be used, and more preferably eggshell powder, especially chicken eggshell powder. As described above, the fine powder calcium carbonate used in the present invention is not particularly limited as long as it is in the above particle size range, and may contain impurities such as inevitable impurities.

  Thus, in the present invention, by blending fine powdered calcium carbonate having a specific particle size distribution as described above with a specific range with respect to the rubber component, excellent on-ice performance and excellent wear resistance are obtained. Highly compatible with sex. In particular, such excellent on-ice performance is exhibited by using the rubber composition so that finely powdered calcium carbonate falls off appropriately in the tread portion of the solid tire, and the dropping hole has an appropriate size. Therefore, it is presumed that the water on ice, which is considered to be the cause of slip or the like, can be effectively removed.

<Other ingredients>
The rubber composition for a solid tire of the present invention may contain other components as long as it contains the rubber component and fine calcium carbonate as described above. Examples of such other components include white fillers, silane coupling agents, vulcanizing agents (sulfur), vulcanization accelerators, vulcanization aids, crosslinking agents, crosslinking accelerators, anti-aging agents, fillers, Various conventionally known compounding agents or additives blended for tires or general rubber compositions such as waxes, softeners, plasticizers, coupling agents, etc. can be blended in conventionally known amounts.

<Solid tire>
The solid tire of the present invention can be obtained using the above rubber composition for a solid tire. Such a solid tire as a whole may be constituted by the rubber composition for a solid tire described above, or only a part thereof (for example, a tread portion in contact with a road surface) may be constituted by the rubber composition for a solid tire. Good.

  Such a solid tire of the present invention can be manufactured with extremely high productivity since it is not necessary to form lug grooves as described above. Such a solid tire is suitable not only for forklift trucks but also for trucks and buses.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

<Examples 1-3 and Comparative Examples 1-4>
<Preparation of rubber composition for solid tire>
In accordance with the formulation shown in Table 1, using a 1.7L Banbury mixer manufactured by Kobe Steel, the components other than sulfur and vulcanization accelerator were filled so that the filling rate was 58%, and the rotation speed was 80 rpm. And kneading at 150 ° C. for 5 minutes. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded material in the amounts shown in Table 1, and then kneaded for 5 minutes at 80 ° C. using a biaxial open roll. The rubber composition for solid tires in the kneaded state of Examples 1 to 4 was obtained.

In Table 1, the details of various blending components used in Examples and Comparative Examples are as follows.
(1) NR: Natural rubber (“TSR20” from Indonesia).
(2) BR: Polybutadiene rubber (“BR150B” manufactured by Ube Industries).
The above NR and BR are rubber components.
(3) Calcium carbonate A: Fine powdered calcium carbonate that is a chicken eggshell powder, and the particle size of 60% of all the particles is in the range of 5 μm to 150 μm.
(4) Calcium carbonate B: Finely divided calcium carbonate manufactured by Hitachi Crushed Stone Co., Ltd., in which 80% of all particles have a particle size of less than 5 μm.
(5) Calcium carbonate C: Fine powdered calcium carbonate which is a chicken eggshell powder, and the particle diameter of 60% or more of all the particles is in a range exceeding 150 μm.
(6) Carbon black: “N330” manufactured by Mitsubishi Chemical Corporation.
(7) Oil: “Diana Process AH-24” manufactured by Idemitsu Kosan Co., Ltd. as process oil
(8) Wax: “Sannokk Wax” manufactured by Ouchi Shinsei Chemical Co., Ltd.
(9) Anti-aging agent: “Antigen 6C” manufactured by Sumitomo Chemical Co., Ltd.
(10) Stearic acid: manufactured by NOF Corporation. Acts as a vulcanization aid.
(11) Zinc oxide: “Silver R” manufactured by Toho Zinc Co. Acts as a vulcanization aid.
(12) Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd.
(13) Vulcanization accelerator: “Noxeller NS” manufactured by Ouchi Shinsei Chemical Co., Ltd.

<Performance evaluation>
And the performance was evaluated on condition of the following using the rubber composition for solid tires obtained individually as mentioned above. The results are shown in Table 1.

<Performance on ice>
Using the rubber composition for a solid tire obtained above, a tread sheet having a thickness of 3 mm was prepared, wound around the tread surface of the solid tire having the following structure, and solidified by vulcanization at 160 ° C. for 15 minutes. Tires were manufactured.

(Structure of solid tire)
As shown in FIG. 1, the tread portion 2 was made of the above tread sheet so as to constitute a solid tire (5 inches wide) having a base portion 1, a tread portion 2, and a sidewall portion 3. In addition, the base part 1 and the side wall part 3 were comprised with the same rubber composition except not containing calcium carbonate in the mixing | blending of said Table 1. FIG. In FIG. 1, R represents a rim.

  The solid tire thus obtained was attached to a battery-type forklift (“Plater” manufactured by Nippon Transportation Co., Ltd.) and actually run in a freezer to perform sensory evaluation on performance on ice such as traction. Specifically, the sensory evaluation result of Comparative Example 1 is indicated by an index of “100”, and the larger the index, the better the performance on ice.

<Abrasion test>
Using the rubber composition for a solid tire obtained above, a test piece having a thickness of 5 mm was prepared by vulcanization at 150 ° C. for 30 minutes, and the following wear test was performed using this test piece. That is, using a Lambourne abrasion tester manufactured by Iwamoto Seisakusho, the wear amount of the test piece was measured at a surface rotation speed of 50 m / min, a load load of 4.5 kg, a sand fall amount of 15 g / min and a slip rate of 50%. The amount of wear is indicated by an index in which the amount of wear in Comparative Example 1 is “100”, and the greater the index, the better the wear resistance.

<Evaluation results>
As is apparent from Table 1, the rubber composition for solid tires of each example, in which fine rubber calcium carbonate having a particle size of 50% or more of all particles in the range of 5 μm or more and 150 μm or less is blended with the rubber component The solid tire obtained by using the product exhibits excellent on-ice performance as compared with the solid tire obtained by using the rubber composition for a solid tire of Comparative Example 1 in which the particle size range is less than the above range. As compared with the solid tire obtained using the rubber composition for a solid tire of Comparative Example 2 having a particle size range exceeding the above range, extremely excellent wear resistance was shown.

  Further, in the case of blending 5 parts by mass or more and 15 parts by mass or less of finely powdered calcium carbonate with respect to 100 parts by mass of the rubber component as in the rubber composition for a solid tire of each example, a comparative example in which the compounding amount is more than that. Excellent abrasion resistance was exhibited as compared with 4, and performance on ice was superior as compared with Comparative Example 3 having a smaller blending amount.

  Therefore, the solid tire obtained using the rubber composition for a solid tire according to the present invention has a high degree of compatibility between excellent on-ice performance and excellent wear resistance. Can be shared with the ice surface. Moreover, since such performance can be obtained without forming lug grooves, the productivity is also excellent.

  Although the embodiments and examples of the present invention have been described as described above, it is also planned from the beginning to appropriately combine the configurations of the above-described embodiments and examples.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a half sectional view of the solid tire of the example of the present invention.

Explanation of symbols

  1 Base part, 2 tread part, 3 side wall part, R rim.

Claims (3)

A rubber composition for a solid tire comprising a rubber component and finely powdered calcium carbonate,
The fine powdered calcium carbonate is blended in an amount of 5 parts by weight to 15 parts by weight with respect to 100 parts by weight of the rubber component, and the fine powdered calcium carbonate has a particle diameter of 50% or more of all particles of 5 μm to 150 μm. A rubber composition for a solid tire in the following range.   The rubber composition for a solid tire according to claim 1, wherein the finely powdered calcium carbonate is eggshell powder.   A solid tire obtained by using the rubber composition for a solid tire according to claim 1.

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