Rubber composition and tire using the same

Abstract

To solve the following problem that: icy and snowy road surfaces have a lower coefficient of friction than general road surfaces, causing slippage; therefore, conventionally, surface roughness has been imparted to improve ice performance (braking capability on ice) of a studless tire, yet this method decreases wet performance.SOLUTION: A rubber composition comprising 30-100 pts.mass of an inorganic filler and 0.5-50 pts.mass of sesame oil cake, relative to 100 pts.mass of a diene rubber.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a rubber composition and a tire using the same, and more particularly to a rubber composition that further enhances ice performance while maintaining or improving wet performance, and a tire using the same.

Background Art

[0002] On icy and snowy roads, the friction coefficient is lower than that on ordinary roads, making it easier to slip. Therefore, conventionally, many methods have been proposed to improve the ice performance (braking performance on ice) of studless tires. For example, a technique for imparting surface roughness to a tire is known for improving ice performance (see, for example, Patent Document 1 below).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, generally, when the surface roughness of a tire is increased, there is a problem that the wet performance deteriorates as an antagonistic performance. Therefore, an object of the present invention is to provide a rubber composition that further enhances ice performance while maintaining or improving wet performance, and a tire using the same.

Means for Solving the Problems

[0005] As a result of intensive studies, the present inventors have found that the above problems can be solved by blending a specific amount of an inorganic filler and linseed press cake with a diene rubber, and have completed the present invention. That is, the present invention provides a rubber composition characterized by containing 30 to 100 parts by mass of an inorganic filler and 0.5 to 50 parts by mass of defatted sesame meal based on 100 parts by mass of a diene rubber.

Advantages of the Invention

[0006] Since the rubber composition of the present invention is characterized by containing 30 to 100 parts by mass of an inorganic filler and 0.5 to 50 parts by mass of defatted sesame meal based on 100 parts by mass of a diene rubber, it is possible to provide a tire having further improved ice performance while maintaining or improving wet performance.

[0007] The defatted sesame meal in the present invention can efficiently impart roughness to the tire tread surface, thereby exhibiting a high scraping effect on the road surface and improving ice performance. Also, it does not impair wet performance. Furthermore, since the defatted sesame meal is excellent in biodegradability, it is rapidly biodegraded even if it falls off on the road surface, which is environmentally friendly.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, the present invention will be described in more detail.

[0009] (Diene Rubber) Examples of the diene rubber used in the present invention include natural rubber (NR), synthetic isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene copolymer rubber (NBR), and the like. Also, the molecular weight and microstructure of the diene rubber used in the present invention are not particularly limited, and it may be end-modified with an amine, amide, silyl, alkoxysilyl, carboxyl, hydroxyl group, etc., or may be epoxidized. The weight average molecular weight (Mw) of the above diene rubber is not particularly limited, but for reasons such as more excellent effects of the present invention, it is preferably 100,000 to 5,000,000, more preferably 200,000 to 3,000,000, and even more preferably 300,000 to 2,000,000. In the present specification, the weight average molecular weight (Mw) is a value in terms of standard polystyrene obtained by gel permeation chromatography (GPC) measurement. Also, the diene rubber preferably has a glass transition temperature (Tg) of -50°C or lower. By defining the Tg in this way, the performance on ice is improved. When a plurality of types of diene rubbers are included, the Tg referred to in the present specification is a value calculated based on the sum of the products of the glass transition temperature of each rubber multiplied by the weight fraction of each rubber, that is, the weighted average. In the calculation, the sum of the weight fractions of each component is taken as 1.0. The glass transition temperature (Tg) referred to in the present invention means the temperature at the midpoint of the transition region measured by a thermogram under the condition of a heating rate of 20°C / min by differential scanning calorimetry (DSC). More preferably, the average Tg is -60°C or lower.

[0010] (Inorganic filler) Specific examples of the inorganic filler used in the present invention include silica, calcium carbonate, magnesium carbonate, talc, clay, alumina, aluminum hydroxide, titanium oxide, calcium sulfate, etc. These may be used alone or in combination of two or more. Among these, silica is preferred because the performance on ice is better.

[0011] Specific examples of silica include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, etc. These may be used alone or in combination of two or more.

[0012] Silica preferably has a CTAB adsorption specific surface area of 50 to 300 m 2 / g, and more preferably 90 to 220 m 2 / g from the viewpoint of improving the performance on ice. The CTAB adsorption specific surface area is a value obtained by measuring the adsorption amount of n-hexadecyltrimethylammonium bromide on the silica surface in accordance with JIS K6217-3:2001 "Part 3: Method for determining specific surface area - CTAB adsorption method".

[0013] In addition, it is preferable to compound carbon black in the rubber composition of the present invention. Specific examples of the carbon black include furnace carbon blacks such as SAF, ISAF, HAF, FEF, GPE, and SRF. These may be used alone or in combination of two or more. Further, from the viewpoint of improving the performance on ice, the carbon black preferably has a nitrogen adsorption specific surface area (N2SA) of 10 to 300 m 2 / g, and more preferably 50 to 150 m 2 / g. The nitrogen adsorption specific surface area (N2SA) is a value measured in accordance with JIS K 6217-2:2001 "Part 2: Method for determining specific surface area - Nitrogen adsorption method - Single point method".

[0014] (Flax press cake) The flax press cake used in the present invention is known and commercially available. For example, it is commercially available from Inochi Plant Care Co., Ltd. under the trade name Kawai Fertilizer Pressed Flax Oil Cake for fertilizer use. Note that the flax press cake used in the present invention does not need to be a defatted product or a fired product. From the viewpoint of improving the effects of the present invention, particularly from the viewpoint of improving wet performance, the flax press cake used in the present invention preferably has an average particle diameter of 10 μm to 2000 μm. The average particle diameter can be the median diameter (D50: the particle diameter of the particles at 50% in the particle diameter cumulative distribution) measured by the laser diffraction method, and can be measured, for example, with a laser diffraction / scattering type particle size distribution measuring device LA-300 (manufactured by Horiba, Ltd.), a laser microscope VK-8710 (manufactured by Keyence Corporation), etc.

[0015] (Mixing ratio of rubber composition) The rubber composition of the present invention is characterized by containing 30 to 100 parts by mass of an inorganic filler and 0.5 to 50 parts by mass of sesame press cake with respect to 100 parts by mass of a diene rubber. When the blending amount of the inorganic filler is less than 30 parts by mass with respect to 100 parts by mass of the diene rubber, the mechanical properties and abrasion resistance of the rubber composition deteriorate. Conversely, when it exceeds 100 parts by mass, the low-temperature flexibility of the rubber composition decreases and the performance on ice deteriorates. When the blending amount of the sesame press cake is less than 0.5 parts by mass with respect to 100 parts by mass of the diene rubber, the addition amount is too small to exhibit the effects of the present invention. Conversely, when it exceeds 50 parts by mass, the wet performance and other physical properties deteriorate.

[0016] From the viewpoint of improving the effects of the present invention, it is preferable to blend 10 to 30 parts by mass of the sesame press cake with respect to 100 parts by mass of the diene rubber. When silica is blended as the inorganic filler, the blending amount of silica is preferably 30 to 70 parts by mass with respect to 100 parts by mass of the diene rubber. When carbon black is blended, the blending amount is preferably 5 to 50 parts by mass with respect to 100 parts by mass of the diene rubber.

[0017] (Other components) In addition to the above-described components, the rubber composition of the present invention may contain a vulcanizing or crosslinking agent; a vulcanization or crosslinking accelerator; zinc oxide, various fillers other than those exemplified above; an antioxidant; a plasticizer; a silane coupling agent; various additives generally blended in rubber compositions such as thermally expandable microcapsules. Such additives can be kneaded by a general method to form a composition and can be used for vulcanization or crosslinking. The blending amounts of these additives can also be set to conventional general blending amounts as long as they do not contravene the object of the present invention.

[0018] In addition, the tire of the present invention can be prepared using the rubber composition of the present invention, and is preferably a pneumatic tire, which can be filled with air, an inert gas such as nitrogen, and other gases. Further, the tire of the present invention is applied to a tread, particularly a cap tread, and is preferably a winter tire such as a studless tire.

Examples

[0019] Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited to the following examples.

[0020] Examples 1 to 7, Comparative Examples 1 to 2 In the formulation (parts by mass) shown in Table 1, the components excluding the vulcanization system (vulcanization accelerator, sulfur) and the curing agent were kneaded in a 1.7-liter sealed Banbury mixer for 5 minutes, then discharged outside the mixer and cooled to room temperature. Subsequently, the composition was put back into the same Banbury mixer, the vulcanization system was added and kneaded to obtain a rubber composition. The obtained rubber composition was press-vulcanized at 170 °C for 10 minutes to obtain a vulcanized rubber test piece, and the physical properties were measured by the test methods shown below.

[0021] Ice performance: The obtained vulcanized rubber test piece (thickness 2 mm) was attached to a flat cylindrical base rubber, and using an inside drum type ice friction tester, the ice friction coefficient was measured under the conditions of a measurement temperature of -1.5 °C, a load of 5.5 kg / cm 2 , and a drum rotation speed of 25 km / h. The obtained ice friction coefficient was expressed as an index with the value of Comparative Example 1 being 100. The larger the index, the greater the ice friction force and the better the ice performance. .

[0022] Wet performance: In accordance with JIS K6394:2007, using a viscoelastic spectrometer (manufactured by Toyo Seiki Seisakusho), tanδ(0 °C) was measured under the conditions of an elongation deformation strain rate of 10 ± 2%, a vibration frequency of 20 Hz, and a temperature of 0 °C. The results were expressed as an index with the value of Comparative Example 1 being 100. The larger the index, the better the wet performance.

[0023] The results are shown together in Table 1.

[0024]

Table 1

[0025] *1: NR (TSR20 manufactured by PT. NUSIRA (SAD)) *2: BR (Nipol BRX5000 manufactured by Zeon Corporation, Japan) *3: Carbon black (Shou Black N339 manufactured by Cabot Japan Ltd.) *4: Silica (ULTRASIL VN3GR manufactured by EVONIK WELLINK) *5: Silane coupling agent (Si69 manufactured by EVONIK LANXING (RIZHAO)) *6: Sesame press cake 1 (Product name: Kawai Fertilizer Pressed Sesame Oil Cake, manufactured by Inochi Plant Care Co., Ltd. The average particle size was adjusted to 100 μm by sieving.) *7: Sesame press cake 2 (Product name: Kawai Fertilizer Pressed Sesame Oil Cake, manufactured by Inochi Plant Care Co., Ltd. The average particle size was adjusted to 10 μm by sieving.) *8: Sesame press cake 3 (Product name: Kawai Fertilizer Pressed Sesame Oil Cake, manufactured by Inochi Plant Care Co., Ltd. The average particle size was adjusted to 2000 μm by sieving.) *9: Sesame press cake 4 (Product name: Kawai Fertilizer Pressed Sesame Oil Cake, manufactured by Inochi Plant Care Co., Ltd. The average particle size was adjusted to 2100 μm by sieving.) *10: Vulcanization accelerator (Nocceler CZ-G manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) *11: Sulfur (Kinka Stamp Oil Ultra Fine Powder Sulfur manufactured by Tsurumi Chemical Industry Co., Ltd.)

[0026] From the results in Table 1, since the rubber compositions of the respective examples are blended with 30 to 100 parts by mass of an inorganic filler and 0.5 to 50 parts by mass of sesame press cake with respect to 100 parts by mass of the diene rubber, the wet performance is maintained or improved and the ice performance is improved as compared with Comparative Example 1. On the other hand, in Comparative Example 2, since the blending amount of the sesame press cake exceeds the upper limit defined in the present invention, the wet performance has decreased.

[0027] The present invention includes the following aspects. Embodiment 1: A rubber composition characterized by containing 30 to 100 parts by mass of an inorganic filler and 0.5 to 50 parts by mass of sesame press cake with respect to 100 parts by mass of a diene rubber. Embodiment 2: The rubber composition according to Embodiment 1, characterized in that the average particle diameter of the sesame press cake is 10 μm to 2000 μm. Embodiment 3: The rubber composition according to Embodiment 1 or 2, characterized in that 30 to 70 parts by mass of silica is included as the inorganic filler with respect to 100 parts by mass of the diene rubber. Embodiment 4: A studless tire using the rubber composition according to any one of Embodiments 1 to 3.

Claims

1. A rubber composition comprising 100 parts by mass of a diene rubber, 30 to 100 parts by mass of an inorganic filler, and 0.5 to 50 parts by mass of sesame press cake.

2. The rubber composition according to claim 1, wherein the sesame press cake has an average particle diameter of 10 μm to 2000 μm.

3. The rubber composition according to claim 1, wherein 30 to 70 parts by mass of silica is contained as the inorganic filler with respect to 100 parts by mass of the diene rubber.

4. A studless tire made using the rubber composition according to claim 1.

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