JP5397441B2 - Rubber composition for tire - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a rubber composition for tires, and more particularly, to a rubber composition for tires that contains a specific terpene resin having a small addition to the environment in place of petroleum-based aroma oil.

Conventionally, petroleum-based aroma oils having excellent performance as rubber plasticizers / softeners have been generally used. However, this aroma oil has the following problems.
(1) Contains a polycyclic aromatic component and has a high environmental impact.
(2) Substitution of petroleum-based aroma oil with paraffin oil or vegetable oil reduces the strength of rubber and wear resistance, and (3) When using highly polar vegetable oil, at low and high temperatures The difference in hardness is undesirably large.

  Therefore, Patent Document 1 proposes a technique of blending non-aromatic process oil into rubber instead of petroleum-based aroma oil having a high environmental load, but this non-aromatic process oil is simply used. However, the process oil is blended with a resin component such as a phenol terpene resin because the rubber properties such as the wear resistance and wet wear of the rubber composition are lowered by the blending of only the rubber composition. In addition, in tread rubber of a studless tire suitable for running on an icy road surface or a snowy road surface, it is also proposed in Patent Document 2 to use a terpene resin in order to impart appropriate flexibility and tackiness to the rubber composition. Yes.

Japanese Patent Laid-Open No. 11-130909 JP 2001-302847 A

  An object of the present invention is to provide a rubber composition for tires containing a specific terpene resin, which is used in a rubber composition based on natural rubber and has a composition property equal to or higher than that of a petroleum-based aroma oil. To do.

  According to the present invention, a rubber composition containing 50 parts by weight or more of natural rubber or polyisoprene rubber out of 100 parts by weight of a diene rubber component does not contain petroleum-based aroma oil, and is measured at 40 ° C. according to JISK7117. A tire rubber composition comprising 1 to 50 parts by weight of a terpene resin having a kinematic viscosity of 100000 mPa · s or less and a kinematic viscosity at 100 ° C. of 1000 mPa · s or less per 100 parts by weight of the diene rubber component. Provided.

  In the present invention, when a terpene resin exhibiting specific conditions instead of a conventional petroleum-based aroma oil is added alone to a diene rubber, in addition to the function as a plasticizer / softener equivalent to the aroma oil, It has been found that a rubber composition for tires can be obtained which reduces the temperature dependence of hardness and is excellent in wear resistance and tensile properties.

  The terpene resins blended and used in the tire rubber composition of the present invention include polyterpene resins, aromatic modified terpene resins, phenol modified terpene resins, and hydrogenated terpene resins obtained by hydrogenating these terpene resins. A material having a kinematic viscosity at 100 ° C. of 100000 mPa · s or less, preferably 80000 mPa · s or less and a kinematic viscosity at 100 ° C. of 1000 mPa · s or less, preferably 800 mPa · s or less is used. Terpene resins satisfying such conditions are commercially available, and are sold, for example, as YS Resin PX 300, YS Resin PX 300N, Dimaron, YS Polyster T30, etc. from Yasuhara Chemical Co., Ltd.

  If the terpene resin has a kinematic viscosity at 40 ° C. of more than 100,000 mPa · s and a kinematic viscosity at 100 ° C. of more than 1000 mPa · s, it is not preferable because workability deteriorates such as difficult pumping.

  In the tire rubber composition of the present invention, the terpene resin is 1 to 50 parts by weight, preferably 5 to 30 parts by weight with respect to 100 parts by weight of the diene rubber containing 50 parts by weight or more of natural rubber or polyisoprene rubber. Blended in quantity. If the blending amount is less than 1 part by weight, the desired effect cannot be exhibited, and if it exceeds 50 parts by weight, the tensile properties and the like are lowered, which is not preferable.

  As a rubber component blended in the tire rubber composition of the present invention, natural rubber (NR) or polyisoprene rubber (IR) is 50 parts by weight or more, preferably 55 parts by weight or more, and these are used alone or as a blend. In addition to these rubber components, other diene-based synthetic rubbers such as various styrene-butadiene copolymer rubbers (SBR), various polybutadiene rubbers (BR), and acrylonitrile-butadiene copolymer rubbers (NBR) may be used. Etc. may be appropriately blended and used.

  The tire rubber composition of the present invention includes a reinforcing agent such as carbon black or silica, a vulcanization or crosslinking agent, a vulcanization or crosslinking accelerator, an antiaging agent, a filler, etc. Various compounding agents generally blended and used can be added, and the blend can be kneaded and vulcanized by a general method and used as a rubber composition for tires. The addition amount of these compounding agents can also be made into the conventional general compounding amount, unless it is contrary to the objective of this invention.

  EXAMPLES Hereinafter, although this invention is demonstrated in more detail according to an Example and a comparative example, it cannot be overemphasized that the technical scope of this invention is not limited to these Examples.

The kinematic viscosities (mPa · s) at 40 ° C. and 100 ° C. of various oils and resins used in the examples of Table 2 below were measured according to JIS K 7117.
The results are shown in Table 1 below.

Preparation of test sample The components excluding sulfur and vulcanization accelerator in the rubber compounding system shown in Table 2 below were kneaded for 3 to 5 minutes with a 1.8 L closed mixer, and the master released when the temperature reached 150 ± 5 ° C. Sulfur and a vulcanization accelerator were added to the batch and kneaded with an 8-inch open roll to obtain a rubber composition. A part of this rubber composition was subjected to the Mooney viscosity test. Subsequently, the remainder of the rubber composition was press vulcanized in a 15 cm × 15 cm × 0.2 cm mold and a disk-shaped mold having a diameter of 49 mm and a thickness of 5 mm at 150 ° C. for 30 minutes to obtain a test piece (rubber sheet ) And subjected to hardness, tensile test and wear test, respectively.

Test Method 1) Mooney Viscosity (ML _{1 + 4} ): In accordance with JIS 6300, using Mooney viscometer with L-shaped rotor (38.1 mm diameter, 5.5 mm thickness), preheating time 1 minute, The measurement was performed under the conditions of a rotation time of 4 minutes, 100 ° C., and 2 rpm.
2) Hardness: Based on JIS K 6253, the hardness at 0 ° C., 20 ° C. and 60 ° C. was measured using a spring type A hardness tester.
3) Tensile properties: In accordance with JIS 6251, a 2 mm sheet was punched with a No. 3 dumbbell, and at a tensile speed of 500 mm / min, 300% modulus (M300), tensile strength (Tb), and elongation at break (Eb) ) Was measured.
4) Abrasion resistance: Measured at a test temperature of 20 ° C., a slip rate of 50%, and a load of 15 N using a Lambourn abrasion tester (manufactured by Iwamoto) in accordance with JIS K6264. The comparative example 1 was set to 100 and evaluated by an index. It shows that abrasion resistance is so favorable that a numerical value is large.

Examples 1-2 and Comparative Examples 1-4
The results are shown in Table 2.

  As can be seen from the results in Table 2, it can be seen that the rubber composition containing the terpene resin that satisfies the conditions of the present invention has a property equal to or higher than that of the petroleum-based aroma oil.

  The specific terpene resin in the present invention can be used extremely effectively as an excellent environmentally friendly plasticizer / softener to replace the conventional petroleum aroma oil in the rubber compound for tires.

Claims (2)

According to JISK7117, a rubber composition containing 100 parts by weight of natural rubber, which does not contain petroleum-based aroma oil and does not contain vegetable oil containing triester of glycerol fatty acid containing oleic acid in a ratio of 60% by weight or more. was measured at a kinematic viscosity of 1650~6800mPa · s at 40 ° C., and a kinematic viscosity at 100 ° C. is a terpene resin which is 35~100mPa · s, the natural rubber 100 parts by weight per 1 to 50 parts by weight of formulation A rubber composition for tires. The rubber composition according to claim 1, wherein the amount of the terpene resin is 5 to 30 parts by weight per 100 parts by weight of natural rubber.