JP6157082B2 - Rubber composition for tread of studless tire and studless tire - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rubber composition for a tread of a studless tire and a studless tire having a tread produced using the rubber composition.

As a plasticizer or softener for rubber, aromatic oils excellent in compounding properties are generally used. However, aromatic oils contain a polycyclic aromatic component and have a carcinogenic problem. In addition, there are problems of fossil resource depletion in the future and a heavy load on the environment.

Then, the example which mix | blended vegetable oil is proposed as a substitute of aromatic oil (refer patent document 1). However, there is room for improvement in that it does not show the same or better blending properties as aromatic oils.

JP 2005-263156 A

The present invention solves the above problems and reduces the amount of components derived from petroleum resources while improving the performance on ice and wear resistance in a well-balanced manner, and a rubber composition for a tread of a studless tire, and the rubber composition. It aims at providing the studless tire which has the tread produced using.

The present invention relates to a rubber composition for a tread of a studless tire containing a rubber component and a vegetable oil produced by a genetically modified plant.

The content of oleic acid in 100% by mass of the constituent fatty acid of the vegetable oil is preferably 85% by mass or more.

The present invention also relates to a studless tire having a tread produced using the rubber composition.

According to the present invention, since it is a rubber composition for a tread of a studless tire containing a rubber component and a vegetable oil produced by a genetically modified plant, an aromatic oil that is a component derived from petroleum resources It is possible to provide a studless tire in which the performance on ice and the wear resistance are improved in a well-balanced manner while reducing the amount of use.

The rubber composition of the present invention contains a rubber component and a vegetable oil produced by a genetically modified plant.

(Rubber component)
Although it does not specifically limit as a rubber component, Rubber | gum derived from resources other than petroleum, such as natural rubber (NR) and epoxidized natural rubber (ENR), can be used conveniently.

When the rubber composition of the present invention contains NR, the content of NR in 100% by mass of the rubber component is preferably 20% by mass or more, more preferably 40% by mass or more, and preferably 80% by mass. Hereinafter, it is 70 mass% or less more preferably. If it is out of the above range, there is a tendency for wear resistance to deteriorate, embrittlement temperature to increase and grip performance (particularly grip performance on ice) to decrease.

If desired, styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), butyl rubber (IIR), acrylonitrile butadiene rubber (NBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR Synthetic rubber such as) can also be used. The synthetic rubber is preferably at least one selected from the group consisting of BR and SBR, more preferably BR because the performance on ice and the wear resistance can be improved in a balanced manner.

When the synthetic rubber is used, it is preferable to use a synthetic rubber produced using a renewable bio-derived raw material as a monomer in consideration of future oil depletion and environmental considerations. For example, in the case of BR, a synthetic rubber produced from such a bio-derived raw material can be obtained by a method in which a catalyst is allowed to act on bioethanol to obtain butadiene, which is then polymerized.

When the rubber composition of the present invention contains BR, the content of BR in 100% by mass of the rubber component is preferably 20% by mass or more, more preferably 30% by mass or more, and preferably 80% by mass. Hereinafter, it is 60 mass% or less more preferably. If it is out of the above range, there is a tendency for wear resistance to deteriorate, embrittlement temperature to increase and grip performance (particularly grip performance on ice) to decrease.

(Vegetable oil)
The rubber composition of the present invention contains a vegetable oil produced by a genetically modified plant (transgenic plant).

Vegetable oils are basically composed of triacylglycerol (TAG) molecules, which are composed of three fatty acid chains esterified to the glycerol skeleton. Vegetable oils are mainly used as edible oils, and those rich in oleic acid are required for the purpose of reducing highly unsaturated fatty acids due to nutritional requirements. Thus, studies have been conducted on metabolic pathways for oleic acid synthesis in plants and genes encoding enzymes for these pathways. As a result, it was observed in some plants that the content of oleic acid was increased by suppressing the action of Δ12-desaturase encoded by the gene Fad2. Based on this result, sunflower oil and soybean oil containing oleic acid at a high content have been developed by genetically modified plants and are already on the market.

Thus, a vegetable oil produced from a genetically modified plant (hereinafter also referred to as a genetically modified vegetable oil) has different characteristics from a vegetable oil obtained from a normal plant. By blending the genetically modified vegetable oil, the performance on ice and the wear resistance can be improved to the same level or more as the aromatic oil.

For gene modification, a known transformation method used when a gene is introduced into a cell can be employed. For example, Agrobacterium into which a vector such as a plasmid containing a DNA constituting a target gene (target gene) is introduced A method of introducing a gene by infecting a genus fungus into a plant cell (Agrobacterium method), a method of shooting a gold particle carrying a DNA constituting a target gene into a cell by a particle gun (particle gun method), a target gene Examples include a method (electroporation method) in which a hole is made in a cell membrane by a voltage in a solution containing a vector into which is incorporated, and the vector is introduced therefrom.

The type of plant is not particularly limited, but rapeseed (canola), corn, soybean, sunflower and cotton are preferable, and canola is more preferable because of high productivity.

There are no particular restrictions on the gene modification sites in the plant, but Δ12-desaturase and Δ6-desaturase encoded by Fad2 can be used because the content of oleic acid is high and the content of linoleic acid and linolenic acid can be reduced. It is preferable that the action of at least one enzyme selected from the group consisting of is suppressed.

The content of oleic acid in 100% by mass of the constituent fatty acid of the genetically modified vegetable oil is preferably 85% by mass or more. If it is less than 85% by mass, the effect of improving the performance on ice and the wear resistance tends to be low. The content of oleic acid is preferably 95% by mass or less, more preferably 90% by mass or less. When it exceeds 95% by mass, the reversion resistance is liable to deteriorate.

The content of linoleic acid in 100% by mass of the constituent fatty acid of the genetically modified vegetable oil is preferably 15% by mass or less, more preferably 8% by mass or less. When it exceeds 15 mass%, there exists a tendency for workability and vulcanization-resistant return property to deteriorate. Although the minimum of content of linoleic acid is not specifically limited, Preferably it is 1 mass% or more.

The content of linolenic acid in 100% by mass of the constituent fatty acid of the genetically modified vegetable oil is preferably 10% by mass or less, more preferably 5% by mass or less. If it exceeds 10% by mass, the workability and vulcanization resistance tend to deteriorate. Although the minimum of content of linolenic acid is not specifically limited, Preferably it is 1 mass% or more.

The fatty acid composition (contents of oleic acid, linoleic acid, and linolenic acid) can be measured by GLC (gas-liquid chromatography).

The content of the genetically modified vegetable oil is preferably 5 to 40 parts by mass with respect to 100 parts by mass of the rubber component. If the amount is less than 5 parts by mass, a sufficient softening effect tends not to be obtained. If the amount exceeds 40 parts by mass, bleeding tends to occur or workability tends to deteriorate.

Since the rubber composition of the present invention uses genetically modified vegetable oil, the amount of oil derived from petroleum resources such as aromatic oils can be reduced while ensuring good compounding properties. The content of the genetically modified vegetable oil in 100% by mass of the total oil is preferably 95% by mass or more, more preferably 99% by mass or more, and further preferably 100% by mass. The content of oil derived from petroleum resources is preferably 5% by mass or less, more preferably 1% by mass or less, and still more preferably 0% by mass (substantially not contained) in 100% by mass of total oil. .

(Filler)
The rubber composition of the present invention may further contain a reinforcing agent (filler). As the filler, carbon black, silica and the like can be used.

The carbon black is not particularly limited, and those generally used in the tire industry such as HAF, ISAF, and SAF can be used, but those having a nitrogen adsorption specific surface area (N ₂ SA) of 100 to 140 m ² / g are preferable. Can be used.
In addition, the nitrogen adsorption specific surface area of carbon black is calculated | required by A method of JISK6217.

When the rubber composition of the present invention contains carbon black, the carbon black content is preferably 15 parts by mass or more, more preferably 25 parts by mass or more, and preferably 100 parts by mass with respect to the rubber component. Is 150 parts by mass or less, more preferably 50 parts by mass or less. If it is in the said range, on-ice performance and abrasion resistance can be improved with a high degree of balance.

There is no restriction | limiting in particular as a silica, For example, what was prepared by the wet method or the dry process can be used.

When the rubber composition of the present invention contains silica, the silica content is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, and preferably 150 parts by mass with respect to 100 parts by mass of the rubber component. It is 40 parts by mass or less, more preferably 40 parts by mass or less. If it is in the said range, on-ice performance and abrasion resistance can be improved with a high degree of balance.

Silica is preferably used in combination with a silane coupling agent. The silane coupling agent is not particularly limited as long as it is conventionally used in the tire field. For example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-trimethoxysilylpropyl) Examples thereof include tetrasulfide, bis (2-triethoxysilylpropyl) tetrasulfide, 3-mercaptopropyltriethoxysilane, and 2-mercaptoethyltrimethoxysilane, and these can be used alone or in any combination. . Among these, bis (3-triethoxysilylpropyl) disulfide, bis (3-triethoxysilylpropyl) tetrasulfide, 3-mercaptopropyltrimethyl are preferred because the reinforcing effect and processability of the silane coupling agent are good. It is preferable to use ethoxysilane, and it is more preferable to use bis (3-triethoxysilylpropyl) disulfide from the viewpoint that processability is particularly good.
The content of the silane coupling agent is preferably 4 to 12 parts by mass with respect to 100 parts by mass of silica.

(Other materials)
In addition to the above components, the rubber composition of the present invention may contain compounding agents conventionally used in the tire industry, such as waxes, anti-aging agents, sulfur, vulcanization accelerators, zinc oxide, stearic acid and the like as necessary. Can be appropriately blended. Moreover, you may mix | blend a phenol resin, a terpene resin, etc. as a thermoplastic resin. Examples of the phenolic resin include polymers such as phenol, alkylphenol, alkoxyphenol, and halogenated phenol. Examples of the terpene-based resin include polymers such as monocyclic unsaturated terpenes such as limonene and dipentene, and bicyclic unsaturated terpenes such as α-pinene.

The rubber composition of the present invention is produced by a general method. That is, it can be produced by a method of kneading the above components with a Banbury mixer, kneader, open roll or the like and then vulcanizing.

The studless tire of this invention is manufactured by a normal method using the said rubber composition. That is, a rubber composition containing various additives as necessary is extruded in accordance with the shape of the tread at an unvulcanized stage, molded by a normal method on a tire molding machine, and other tires. After bonding together with the members to form an unvulcanized tire, the tire can be manufactured by heating and pressing in a vulcanizer.

The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

Hereinafter, various chemicals used in Examples and Comparative Examples will be described.
NR: SIR20
BR: BR150B manufactured by Ube Industries, Ltd.
Wax: Ozoace 0355 manufactured by Nippon Seiki Co., Ltd.
Carbon black: N220 (N ₂ SA: 111 m ² / g) manufactured by Cabot Japan
Silica: Ultrasil VN3 manufactured by Degussa
Silane coupling agent: Si266 (bis (3-triethoxysilylpropyl) disulfide) manufactured by Degussa
Vegetable oil 1: Natreon canola oil manufactured by Dow AgroSciences (genetically modified vegetable oil, oleic acid content: 70 mass%, linoleic acid content: 18 mass%, linolenic acid content: 7 mass%)
Vegetable oil 2: Natreon canola oil manufactured by Dow AgroSciences (genetically modified vegetable oil, oleic acid content: 85 mass%, linoleic acid content: 8 mass%, linolenic acid content: 4 mass%)
Process oil: Aroma oil manufactured by JX Nippon Oil & Energy Co., Ltd. Zinc oxide: Zinc Hua No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Stearic acid: Sulfur manufactured by NOF Corporation: Tsurumi Chemical Co., Ltd. Powder Sulfur Vulcanization Accelerator 1: Noxeller CZ (N-cyclohexyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Vulcanization accelerator 2: Noxeller D (1,3-diphenylguanidine) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Anti-aging agent: Antigen 6C manufactured by Sumitomo Chemical Co., Ltd.

<Examples and Comparative Examples>
Using a 1.7-L Banbury mixer manufactured by Kobe Steel, Inc., out of the chemicals in the blending amounts shown in Table 1, other than sulfur and vulcanization accelerator were charged so that the filling rate was 58%. The mixture was kneaded for 3 to 8 minutes under the condition of a rotational speed of 80 rpm until the indicated temperature of the kneader reached 140 ° C. Silica was added in two portions. Sulfur and a vulcanization accelerator were added to this mixture and kneaded for 3 minutes at 50 ° C. using an open roll to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition was molded into a size necessary for the following evaluation, and press vulcanized at 160 ° C. for 20 minutes to obtain vulcanized rubber compositions of Examples and Comparative Examples.

(Measurement of performance on ice)
The performance on ice was evaluated by pressing the vulcanized rubber composition onto the surface of ice placed in a temperature-controlled temperature controlled room with a constant load and detecting the frictional force when sliding at a constant speed. The temperature of the temperature-controlled room was −5 ° C., the ice temperature was −2 ° C., the load (installation pressure) was 2 kg / cm ² , and the speed was 20 km / h. The results are shown as an index with Comparative Example 1 as 100. The larger the index, the greater the frictional force on ice, indicating superior performance on ice (grip performance on ice).

(Measurement of wear resistance)
Lambone wear of test pieces for lambone wear test obtained from each vulcanized rubber composition under the conditions of load load of 2.5 kg, temperature of 20 ° C., slip rate of 40%, test time of 2 minutes with a lambbone wear tester The amount was measured, and the amount of lamborn wear of Comparative Example 1 was set to 100, and the amount of lamborn wear of each formulation was displayed as an index. It shows that it is excellent in abrasion resistance, so that an index | exponent is large.

From Table 1, reference examples and examples in which genetically modified vegetable oils (vegetable oils 1 and 2) were blended were compared with comparative examples in which aromatic oils (process oils) were blended in place of the genetically modified vegetable oils. In addition, the wear resistance was improved in a well-balanced manner. Moreover, Examples 4-6 which mix | blended the vegetable oil 2 had the tendency for the improvement effect of each performance to be larger than the reference examples 1-3 which mix | blended the vegetable oil 1. FIG.

Claims (2)

Containing a rubber component and a vegetable oil extracted from a genetically modified plant;
The vegetable oil is canola oil;
A tread of a studless tire in which the content of oleic acid in 100% by mass of the constituent fatty acid of the vegetable oil is 85% by mass or more , the content of linoleic acid is 1 to 8% by mass, and the content of linolenic acid is 1 to 10% by mass. Rubber composition. Studless tire having a tread produced from the claim 1 Symbol placement of the rubber composition.