JP6617011B2 - Rubber composition for studless tire - Google Patents

Description

  The present invention relates to a rubber composition for studless tires.

  The snowy and snowy road surface is significantly slippery and slippery compared to the general road surface. Therefore, in tread rubber for studless tires, various methods have been proposed for forming tread rubber from foamed rubber and blending hollow particles and fibers in order to increase the friction force on ice and improve braking performance on ice. Yes.

  For example, Patent Documents 1 and 2 disclose that on-ice braking performance is improved by blending nylon fiber with diene rubber, but in order to meet the strict demands of the market, further on-ice braking performance is disclosed. There is a need for improvement.

  There is also an increasing demand for stable driving performance on wet road surfaces.

  Patent Document 3 discloses a rubber composition in which porous polyamide particles are blended with a diene-based rubber, but has little structural and mechanical anisotropy, high elasticity, workability, and fracture. The object is to provide a rubber composition excellent in characteristics and heat resistance, and there is no description about the effect of the studless tire on the braking performance on ice and the steering stability performance on the wet road surface.

JP 2011-12248 A JP 2010-248456 A JP 2002-173557 A

  In view of the above, an object of the present invention is to provide a rubber composition for a studless tire that can improve the braking performance on ice and the steering stability performance on a wet road surface.

The rubber composition for studless tires according to the present invention contains 0.5 to 30 parts by mass of porous nylon particles having a BET specific surface area of 5 to 50 m ² / g with respect to 100 parts by mass of the diene rubber. is there.

  Moreover, a studless tire can be produced using the rubber composition as a tread rubber.

  According to the present invention, braking performance on ice and steering stability performance on a wet road surface can be improved.

  Hereinafter, matters related to the implementation of the present invention will be described in detail.

  The rubber composition for studless tires according to this embodiment contains 0.5 to 30 parts by mass of porous nylon particles with respect to 100 parts by mass of the diene rubber.

  Examples of the diene rubber used as the rubber component in the rubber composition include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), and styrene-isoprene copolymer. Examples thereof include rubber, butadiene-isoprene copolymer rubber, and styrene-isoprene-butadiene copolymer rubber. These diene rubbers can be used alone or in a blend of two or more. The diene rubber is preferably natural rubber, butadiene rubber, styrene butadiene rubber, or a blend of two or more thereof.

  As the diene rubber, it is preferable to use a blend of natural rubber and another diene rubber, and it is particularly preferable to use a blend rubber of natural rubber (NR) and butadiene rubber (BR). In that case, the ratio of the two is not particularly limited, but the ratio of NR / BR is 30/70 to 80 in terms of mass ratio in consideration of the balance between the low temperature characteristics of the rubber composition and processability and tear resistance. / 20, preferably 40/60 to 70/30.

  The porous nylon particles according to this embodiment are not particularly limited. For example, nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612, nylon 46, nylon 6/66, nylon 6/66 / 12, Nylon 6/66/610, Nylon 69, Nylon MXD6, Nylon 6T, Nylon 6 / 6T, Nylon 9T, etc., can be used. It is preferable. Examples of such porous nylon particles include “nylon 6 porous fine particles” sold by Toray Industries, Inc.

  The average particle size of the porous nylon particles is not particularly limited, but is preferably 1 to 100 μm, more preferably 1 to 50 μm, and further preferably 1 to 30 μm.

  Here, in this specification, the average particle diameter is a value measured by a laser diffraction / scattering method, for example, a laser diffraction particle size distribution measurement manufactured by Shimadzu Corporation using a red semiconductor laser (wavelength 680 nm) as a light source. It is the 50% particle diameter (median diameter) of the particle size distribution (volume basis) measured by the apparatus “SALD-2200”.

Moreover, in this specification, porous means having a pore on the surface. BET specific surface area of the porous nylon particles (measured according to BET method according to JIS K6430) is not particularly limited, is preferably from 0.1 to 100 m ² / g, is 1~80m ² / g Is more preferable, and it is still more preferable that it is 5-50 m < ² > / g.

  The blending amount of the porous nylon particles is 0.5 to 30 parts by mass, preferably 5 to 30 parts by mass, and more preferably 15 to 30 parts by mass with respect to 100 parts by mass of the diene rubber. preferable. When the blending amount of the porous nylon particles is 0.5 parts by mass or more with respect to 100 parts by mass of the diene rubber, it is excellent in improving the braking performance on ice and the steering stability performance on the wet road surface, and is 30 masses. By being below the part, the effect of improving the braking performance on ice and the steering stability performance on the wet road surface can be obtained without reducing the wear resistance performance.

  By blending porous nylon particles with the diene rubber, it is possible to improve the braking performance on ice and the steering stability performance on the wet road surface. The reason is considered as follows. That is, the porous nylon particles can exhibit a water film removal effect on the road surface, and can improve braking performance on ice and steering stability performance on a wet road surface. Moreover, although the porous nylon particle is a particle having flexibility, the flexibility is further increased by absorbing water, and the adhesion to the road surface is increased. As a result, the frictional force with the road surface is increased, and it is considered that the braking performance on ice and the steering stability performance on the wet road surface can be improved.

  You may mix | blend a reinforcing filler with the rubber composition which concerns on this embodiment.

  As the reinforcing filler, it is preferable to use carbon black and / or silica. That is, the reinforcing filler may be carbon black alone, silica alone, or a combination of carbon black and silica. Preferably, carbon black or a combination of carbon black and silica is used. The compounding amount of the reinforcing filler is not particularly limited. For example, the reinforcing filler is preferably 10 to 150 parts by mass, more preferably 20 to 100 parts by mass, and still more preferably 100 parts by mass of the diene rubber. 30 to 80 parts by mass.

  The carbon black is not particularly limited, and various known varieties can be used. As a compounding quantity of carbon black, it is preferable that it is 10-80 mass parts with respect to 100 mass parts of diene rubbers, More preferably, it is 15-50 mass parts.

  The silica is not particularly limited, but wet silica such as wet precipitation silica or wet gel silica is preferably used. When silica is blended, the blending amount is preferably 10 to 50 parts by weight, more preferably 15 to 50 parts with respect to 100 parts by weight of the diene rubber from the viewpoint of balance of tan δ of rubber and reinforcement. Part by mass.

  When silica is blended, a silane coupling agent such as sulfide silane or mercaptosilane is preferably used in combination, and the blending amount is preferably 2 to 20% by mass with respect to the silica blending amount.

  In the rubber composition according to the present embodiment, in addition to the above-described components, process oil, zinc white, stearic acid, softener, plasticizer, wax, anti-aging agent, vulcanization used in ordinary rubber industry Compounding chemicals such as an agent and a vulcanization accelerator can be appropriately blended within a normal range. Furthermore, known components that improve braking performance on ice, such as plant granules (pulverized products of seed shells, fruit nuclei, etc.) and porous carbides (charcoal, bamboo charcoal, etc.) can also be blended.

  Examples of the vulcanizing agent include sulfur components such as powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur. Although not particularly limited, the blending amount is 100 parts by mass of diene rubber. It is preferable that it is 0.1-10 mass parts with respect to it, More preferably, it is 0.5-5 mass parts. Moreover, as a compounding quantity of a vulcanization accelerator, it is preferable that it is 0.1-7 mass parts with respect to 100 mass parts of diene rubbers, More preferably, it is 0.5-5 mass parts.

  The rubber composition can be prepared by kneading according to a conventional method using a commonly used mixer such as a Banbury mixer, a kneader, or a roll. For example, in the first mixing stage (non-pro kneading process), diene rubber is kneaded with porous nylon particles and other additives excluding vulcanizing agent and vulcanization accelerator, and then obtained. A rubber composition can be prepared by adding a vulcanizing agent and a vulcanization accelerator to the mixture in the final mixing stage (pro-kneading process) and kneading.

  The rubber composition can be preferably used as a tread rubber of a studless tire. There are tread rubbers with a two-layer structure of cap rubber and base rubber, and those with a single-layer structure in which both are integrated. If present, the tread rubber is made of the rubber composition, and if it has a two-layer structure, the cap rubber is made of the rubber composition.

  The studless tire of the present invention can be manufactured according to a conventional method. For example, an unvulcanized tire is produced by extruding the rubber composition and combining the obtained unvulcanized rubber as a tread rubber with another member such as an unvulcanized sidewall rubber member. Subsequently, a studless tire can be manufactured by vulcanization-molding the obtained unvulcanized tire.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

  Using a Banbury mixer, according to the composition (parts by mass) shown in Table 1 below, first, in the first mixing stage, components other than sulfur and vulcanization accelerator are added and mixed (discharge temperature = 160 ° C.), and then obtained. In the final mixing stage, sulfur and a vulcanization accelerator were added to and mixed with the resulting mixture (discharge temperature = 90 ° C.) to prepare a rubber composition.

  The details of each component in Table 1 are as follows.

・ NR: RSS # 3
-BR: Hisys BR, "BR01" manufactured by JSR Corporation
・ Carbon black: “N339 Seast KH” manufactured by Tokai Carbon Co., Ltd.
・ Silica: “Nip Seal AQ” manufactured by Tosoh Silica Co., Ltd.
Silane coupling agent: “Si75” manufactured by Evonik
Paraffin oil: “Process P200” manufactured by JX Nippon Oil & Energy Corporation
Nylon particles: “Nylon 12 true spherical particles” manufactured by Toray Industries, Inc. (average particle size: 6 to 14 μm)
-Porous nylon particles: "Nylon 6 porous fine particles" manufactured by Toray Industries, Inc. (average particle size 10 to 16 µm, BET specific surface area 6 to 19 m ² / g)
Nylon fiber: Commercially available nylon 6 fiber was pulverized with a ball mill and classified. (Average fiber length 50-300 μm)
-Porous calcium carbonate: Commercially available coral powder was pulverized with a ball mill and classified. (Average particle size 10-60 μm, BET specific surface area 0.8-3.5 m ² / g)
・ Stearic acid: “Lunac S-20” manufactured by Kao Corporation
・ Zinc flower: “Zinc flower 1” manufactured by Mitsui Mining & Smelting Co., Ltd.
Anti-aging agent: “Antigen 6C” manufactured by Sumitomo Chemical Co., Ltd.
・ Wax: Nippon Seiwa Co., Ltd. “OZOACE0355”
・ Sulfur: “Powder sulfur” manufactured by Tsurumi Chemical Co., Ltd.
・ Vulcanization accelerator: “Soxinol CZ” manufactured by Sumitomo Chemical Co., Ltd.

  Each obtained rubber composition was extruded into a desired shape using an extruder to produce a tread rubber. Each of the obtained tread rubbers was applied to a tread of a tire having a tire size of 195 / 65R15, and a studless tire was produced by vulcanization molding according to a conventional method.

  Each of the obtained tires was evaluated for wear resistance performance, braking performance on ice, and steering stability performance on a wet road surface. The evaluation method is as follows.

-Wear resistance performance: The above four tires are mounted on a 2000 cc 4WD vehicle, run on a general dry road surface by 10,000 km while rotating left and right every 2500 km, and the average value of the four remaining tread groove depths after running, It was displayed as an index with the value of Comparative Example 1 being 100. The higher the index, the better the wear resistance.

-On-ice braking performance: The above four tires are mounted on a 2000 cc 4WD vehicle, and the braking distance is measured by operating the ABS from 40 km / h on an icy road (temperature -3 ± 3 ° C) (n = 10 And the reciprocal of the braking distance are expressed as an index with the value of Comparative Example 1 as 100. The larger the index, the shorter the braking distance and the better the braking performance on the road surface on ice.

-Steering stability performance on wet road surface: The driver in charge of sensory tests evaluated the steering stability performance by driving on a wet road surface at high speed while paying attention to steering response and running stability. The result is +2 for superior, +1 for slightly superior, ± 0 for equivalent, -1 for slightly inferior, and -2 for inferior compared to Comparative Example 1 of the control. And shown in the table.

  The results are as shown in Table 1. From the comparison between Comparative Examples 1-6 and Examples 1-3, 0.5-30 parts by mass of porous nylon particles are contained with respect to 100 parts by mass of the diene rubber. By doing so, the effect of improving the braking performance on ice and the steering stability performance on the wet road surface was recognized without deteriorating the wear resistance performance.

  The rubber composition for studless tires of the invention can be used for various tires such as passenger cars, light trucks, trucks and buses.

Claims (2)

A rubber composition for studless tires containing 0.5 to 30 parts by mass of porous nylon particles having a BET specific surface area of 5 to 50 m ² / g with respect to 100 parts by mass of diene rubber. A studless tire produced by using the rubber composition according to claim 1 as a tread rubber.