JP6105351B2 - Rubber composition for tire and pneumatic tire - Google Patents

Description

The present invention relates to a rubber composition for tires and a pneumatic tire produced using the rubber composition.

Conventionally, as softeners such as rubber components, aromatic oils with excellent compounding properties are generally used. However, since aromatic oils contain a large amount of polycyclic aromatic components, the burden on the environment is high. There is a problem. As a solution, it has also been proposed to use an environmentally friendly aromatic oil such as T-DAE with a polycyclic aromatic content reduced to less than 3%, but it can be obtained compared to conventional aromatic oils. There is a problem that the breaking strength of the rubber composition is lowered.

It has also been proposed to use tall oil (tall oil fatty acid or its derivatives or tall oil rosin), but it is recovered as a by-product during kraft pulp manufacture and is a mixture of multiple components, so the quality is There is an essential problem that it is not constant, and it is difficult to always provide desired performance.

The present invention solves the above-mentioned problems, and can provide good processability, rubber strength, initial grip, grip performance and wear resistance, and a rubber composition for tires using a softening agent having a low environmental load, and the rubber composition It aims at providing the pneumatic tire produced using the thing.

The present invention relates to a rubber composition for a tire containing a rubber component and an α-pinene derivative.

It is preferable that the boiling point of the α-pinene derivative is 200 ° C. or higher.

The viscosity of the α-pinene derivative at 20 ° C. is preferably 100,000 mPa · s or less.

The α-pinene derivative is selected from the group consisting of α-pinene hydroxide, α-pinene esterified product, α-pinene ether, α-pinene-alcohol conjugate, and derivatives thereof. It is preferable that there is at least one.

The α-pinene derivative is preferably terpineol and / or a derivative thereof.

The α-pinene derivatives are terpineol, terpinyl methyl ether, dihydroterpineol, dihydroterpinel acetate, 4- (1′-acetoxy-1′-methylethyl) cyclohexanol acetate, 2- (1-methyl-1- It is preferably at least one selected from the group consisting of (4-methyl-3-cyclohexenyl) ethoxy) ethanol, isobornylcyclohexanol, dihydroterpinyloxyethanol, and dihydroterpinylmethyl ether.

The present invention also relates to a pneumatic tire produced using the rubber composition.

According to the present invention, since it is a rubber composition for tires using an α-pinene derivative, good processability, rubber strength, initial grip and grip performance are used in spite of using a softening agent having a low environmental load. In addition, a pneumatic tire excellent in these performances can be provided.

The rubber composition for tires of the present invention contains a rubber component and an α-pinene derivative.
That is, the present invention does not use α-pinene as a main component of turpentine oil obtained by distillation purification of pine sap-derived gum turpentine oil, which is generally used as a fragrance raw material or resin raw material. The α-pinene derivative was used as a softening agent. Since the tire manufacturing process is mainly performed at around 150 ° C., a terpene resin having a boiling point of 155 ° C. polymerized to raise the boiling point is used as a softening agent. A derivative whose boiling point is raised by modifying pinene is blended as a softening agent.

Therefore, a single compound α-pinene is used as a raw material, and a certain quality derivative is obtained. By blending this as a softening agent, good processability is obtained and a desired crosslinking density (vulcanization degree) is obtained. Can be stably produced. Therefore, a vulcanized rubber having stable workability, rubber strength, initial grip, grip performance and abrasion resistance can be obtained, and the environmental load can be reduced.

The boiling point (standard boiling point) of the α-pinene derivative is preferably 200 ° C. or higher, more preferably 210 ° C. or higher, and further preferably 220 ° C. or higher. If it is lower than 200 ° C., it volatilizes during the production of the tire, and the function as a softener may not be sufficiently exhibited. Although an upper limit is not specifically limited, Preferably it is 400 degrees C or less, More preferably, it is 350 degrees C or less.

The viscosity of the α-pinene derivative at 20 ° C. is preferably 1,000,000 mPa · s or less, more preferably 100,000 mPa · s or less, and still more preferably 10,000 mPa · s or less. If it exceeds 1,000,000 mPa · s, the function as a softener may not be achieved. The lower limit is not particularly limited, but the viscosity at 20 ° C. is preferably 0.01 mPa · s or more, more preferably 0.1 mPa · s or more, and further preferably 1.0 mPa · s or more. In the present invention, the viscosity at 20 ° C. can be measured using a B-type viscometer under the temperature condition.

The α-pinene derivative is not particularly limited as long as it is a compound in which the boiling point and viscosity can be used as a softening agent by applying various modifications such as introduction of a functional group to α-pinene. Α-Pinene-derived hydroxides (hydrolysates) such as hydroxides (hydrolysates), α-pinene-derived esterified products such as α-pinene esterified products, α-pinene ethers, etc. Examples include etherified products derived from pinene, conjugates of α-pinene and alcohol, and various derivatives thereof.

Suitable α-pinene derivatives include, for example, terpineol (a mixture of isomers such as α-terpineol, β-terpineol, and γ-terpineol obtained by hydroxylating α-pinene). The physical and chemical properties of the isomers are almost the same, and terpineol has a high boiling point of 200 ° C. or higher due to having a hydroxyl group. It can be suitably used as a softener in the kneading step.

Suitable α-pinene derivatives include compounds obtained by hydrogenating terpineol, compounds obtained by hydrogenating terpineol and further esterifying, compounds obtained by hydroxylating terpineol and further esterifying, and terpineol by ether. A terpineol derivative such as a compound obtained by the conversion.

Preferred examples of the compound obtained by hydrogenating terpineol include dihydroterpineol (a mixture of isomers such as p-menthan-1-ol and p-menthan-8-ol obtained by hydrogenating terpineol). Can be mentioned. Preferable examples of the compound obtained by hydrogenating terpineol and further esterifying include compounds obtained by condensation of dihydroterpineol and carboxylic acid compounds. Specifically, dihydroterpinel acetate (dihydroterpineol and And a mixture of isomers such as p-menthan-1-yl acetate and p-menthan-8-yl acetate) obtained by condensation with acetic acid. Preferable examples of the compound obtained by hydroxylating terpineol and further esterifying include 4- (1′-acetoxy-1′-methylethyl) cyclohexanol acetate. Preferred examples of compounds obtained by etherifying terpineol include terpinyl methyl ether, 2- (1-methyl-1- (4-methyl-3-cyclohexenyl) ethoxy) ethanol, dihydroterpinyloxyethanol, dihydro Examples include terpinyl methyl ether.

Moreover, as a suitable example of the conjugate of α-pinene and alcohol, isobornylcyclohexanol, which is a conjugate of α-pinene and cyclohexanol, can be mentioned.

In addition, the physical and chemical properties of the isomers of dihydroterpineol are almost the same, and in addition to the same advantages as terpineol, there is no double bond, so there is no effect on the crosslinking reaction with sulfur. Excellent workability can be obtained. The physical and chemical properties of the isomers of dihydroterpinyl acetate are almost the same, and in addition to the same advantages as dihydroterpineol, it is further esterified and hardly generates acidic protons. Since side reactions are unlikely to occur, very good processability can be obtained. Since 4- (1'-acetoxy-1'-methylethyl) cyclohexanol acetate has a high boiling point and almost no odor, it can be suitably used as a softening agent. A compound obtained by etherifying terpineol, a conjugate of α-pinene and alcohol, has the same advantages as described above.

The content of the α-pinene derivative is preferably 100 parts by mass or more and more preferably 120 parts by mass or more with respect to 100 parts by mass of the rubber component. The content is preferably 250 parts by mass or less, and more preferably 200 parts by mass or less. If it is less than 100 parts by mass, grip performance may be reduced. If it exceeds 250 parts by mass, the wear resistance and rubber strength may be reduced.

The rubber composition of the present invention may contain a softening agent other than the α-pinene derivative within a range that does not inhibit the effect, but the content of the α-pinene derivative in 100% by mass of the softening agent is referred to as an environmental load. From the viewpoint, it is preferably 70% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass.

Examples of the rubber component used in the rubber composition of the present invention include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), and ethylene. Examples include diene rubbers such as propylene diene rubber (EPDM), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), and butyl rubber (IIR). A rubber component may be used independently and may use 2 or more types together. Of these, NR, BR, and SBR are preferable, and SBR is more preferable because grip performance and wear resistance can be obtained in a well-balanced manner. A rubber component containing oil-extended oil can also be used, but in that case, the oil-extended oil can be removed in advance and a sufficient amount of α-pinene derivative can be blended from the viewpoint that the effects of the present invention can be sufficiently obtained. It is preferable to make it.

The SBR is not particularly limited, and for example, emulsion polymerization styrene butadiene rubber (E-SBR), solution polymerization styrene butadiene rubber (S-SBR) and the like can be used.

The styrene content of SBR is preferably 20% by mass or more, more preferably 25% by mass or more. When it is less than 20% by mass, sufficient grip performance tends to be not obtained. The styrene content is preferably 60% by mass or less, and more preferably 50% by mass or less. When it exceeds 60% by mass, not only the wear resistance decreases, but also the temperature dependency increases, and the performance change with respect to the temperature change tends to increase. In the present invention, the styrene content of SBR is calculated by H ¹ -NMR measurement.

The content of SBR in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 15% by mass or more. If it is less than 10% by mass, sufficient heat resistance, grip performance and wear resistance tend to be not obtained. Further, the upper limit of the SBR content is not particularly limited, and may be 100% by mass.

In addition to the above components, the rubber composition of the present invention includes compounding agents generally used in the tire industry, such as fillers, vulcanizing agents such as stearic acid, zinc oxide, sulfur, and vulcanization accelerators. You may mix | blend materials, such as these, suitably.

Examples of the filler include carbon black, silica, calcium carbonate, alumina, clay, talc, and the like. Among these, carbon black is preferable from the viewpoint of low fuel consumption and wear resistance. Examples of carbon black include carbon black produced by an oil furnace method, and two or more types having different colloidal characteristics may be used in combination. Specific examples include GPF, HAF, ISAF, and SAF. Among these, SAF is preferable.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 100 m ² / g or more, and more preferably 110 m ² / g or more. If it is less than 100 m < ² > / g, there exists a tendency for grip performance to fall. The _N 2 SA is preferably from 300 meters ² / g or less, 180 m ² / g or less is more preferable. When it exceeds 300 m < ² > / g, favorable dispersion | distribution is difficult to be obtained and there exists a tendency for abrasion resistance to fall. In addition, the nitrogen adsorption specific surface area of carbon black is calculated | required based on JISK6217-2: 2001.

The content of carbon black is preferably 100 parts by mass or more, more preferably 150 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 100 parts by mass, sufficient wear resistance and grip performance may not be obtained. The content is preferably 300 parts by mass or less, more preferably 250 parts by mass or less. If it exceeds 300 parts by mass, grip performance may be reduced.

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, a kneader, an open roll or the like and then vulcanizing.

The rubber composition of the present invention can be suitably used for tire treads.

The pneumatic tire of the present invention is produced by a usual method using the rubber composition. That is, a rubber composition containing various additives as necessary is extruded in accordance with the shape of the tire at an unvulcanized stage, and molded by a normal method on a tire molding machine. Laminate together with the member to form an unvulcanized tire. This unvulcanized tire can be heated and pressurized in a vulcanizer to produce the pneumatic tire of the present invention.

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

<Preparation Example 1>
1 kg of S-SBR (Nipol NS522 manufactured by Nippon Zeon Co., Ltd.) was dissolved in 10 L of toluene (manufactured by Kanto Chemical Co., Ltd., special grade). Addition gave a precipitate. The precipitate was dried under reduced pressure (internal pressure 10 Pa, temperature 50 ° C.) for 24 hours to obtain 730 g of deoiled SBR.

Below, various chemical | medical agents used by the Example and the comparative example are demonstrated.
SBR: SBR produced in Preparation Example 1
Carbon black: Dia Black A N110 (SAF, N ₂ SA: 142 m ² / g) manufactured by Mitsubishi Chemical Corporation
Softener (1): VivaTec500 (T-DAE) manufactured by H & R
Softener (2): Turpentine oil manufactured by Nippon Terpene Chemical Co., Ltd. (α-pinene, boiling point: 150 ° C., viscosity: 0.32 mPa · s (20 ° C.))
Softener (3): Terpineol C (Terpineol, boiling point: 217 ° C., viscosity: 34 mPa · s (20 ° C.)) manufactured by Nippon Terpene Chemical Co., Ltd.
Softener (4): Dihydroterpineol manufactured by Nippon Terpene Chemical Co., Ltd. (boiling point: 208 ° C., viscosity: 80 mPa · s (20 ° C.))
Softening agent (5): dihydroterpinyl acetate manufactured by Nippon Terpene Chemical Co., Ltd. (boiling point: 223 ° C., viscosity: 7 mPa · s (20 ° C.))
Softener (6): Tersolve THA-70 (ester 1, 4- (1'-acetoxy-1'-methylethyl) -octhexanol acetate, manufactured by Nippon Terpene Chemical Co., Ltd., boiling point: 223 ° C, viscosity: 144 mPa · s (20 ° C))
Softener (7): Tersolve THA-90 (ester 2, 4- (1'-acetoxy-1'-methylethyl) -octhexanol acetate, Nippon Terpene Chemical Co., Ltd., boiling point: 223 ° C, viscosity: 198 mPa · s (20 ° C))
Softener (8): Tersolve TOE-100 manufactured by Nippon Terpene Chemical Co., Ltd. (boiling point: 270 ° C., viscosity: 62 mPa · s (20 ° C.))
Softening agent (9): dihydroterpinyloxyethanol (ether 1,2- (1-methyl-1- (4-methyl-3-cyclohexenyl) ethoxy) ethanol manufactured by Nippon Terpene Chemical Co., Ltd., boiling point: 250 ° C., viscosity: 51 mPa · s (20 ° C.))
Softener (10): Tersolve MTPH (alcohol, isobornylcyclohexanol, boiling point: 310 ° C., viscosity: 89,000 mPa · s (20 ° C.)) manufactured by Nippon Terpene Chemical Co., Ltd.
Softener (11): Terpinyl methyl ether (boiling point: 216 ° C., viscosity: 4.9 mPa · s (20 ° C.)) manufactured by Nippon Terpene Chemical Co., Ltd.
Softener (12): dihydroterpinyl methyl ether manufactured by Nippon Terpene Chemical Co., Ltd. (boiling point: 201 ° C., viscosity: 4.9 mPa · s (20 ° C.))
Stearic acid: Zinc stearate manufactured by NOF Corporation: Zinc oxide sulfur manufactured by Mitsui Metal Mining Co., Ltd .: Sulfur powder vulcanization accelerator manufactured by Tsurumi Chemical Industry Co., Ltd .: Ouchi Shinsei Chemical Industry Noxeller NS made

<Examples and Comparative Examples>
In accordance with the contents of Table 1, in the BP Banbury mixer, the components excluding sulfur and the vulcanization accelerator were kneaded for 3 minutes under the condition of 150 ° C., and further, sulfur and the vulcanization accelerator were blended, and 50 rolls with an open roll. The mixture was kneaded for 5 minutes under the condition of ° C. to produce an unvulcanized rubber sheet. Further, the unvulcanized rubber sheet was press vulcanized for 12 minutes at 170 ° C. to prepare a vulcanized rubber sheet.
Further, the obtained unvulcanized rubber sheet is formed into a tread shape and bonded together with other tire members on a tire molding machine to form an unvulcanized tire, and vulcanized at 170 ° C. for 12 minutes, 11 × 1 10-5 size cart tires were manufactured.

The obtained unvulcanized rubber sheet, vulcanized rubber sheet, and cart tire were evaluated by the following test methods. The results are shown in Table 1.

(Processability)
A test piece of a predetermined size was prepared from an unvulcanized rubber sheet, and heated at 130 ° C. by preheating for 1 minute using a Mooney viscosity tester according to JIS K6300 “Testing method for unvulcanized rubber”. The Mooney viscosity ML _{1 + 10} (130 ° C.) at the time when 10 minutes had passed after rotating the large rotor under the temperature condition was measured, and Comparative Example 1 was indexed as 100. It shows that workability is excellent, so that a value is small.

(Degree of vulcanization)
The vulcanized rubber sheet was immersed in toluene at 25 ° C. for 24 hours, and the volume change rate (SWELL) before and after the immersion was measured. Smaller values indicate less variation in cross-linking, which is preferable.

(Rubber strength)
Using a No. 3 dumbbell-shaped test piece made of a vulcanized rubber sheet, a tensile test was conducted according to JIS K6251 “Vulcanized rubber and thermoplastic rubber-Determination of tensile properties”, and the tensile strength TB at break ( MPa) and elongation EB (%) were measured and indexed with Comparative Example 1 taken as 100. The larger the value, the better the rubber strength.

(Grip performance)
The prepared tire was mounted on a cart, and the test course of 1 km and 2 km was run 8 times. The tire grip performance of Comparative Example 1 was set to 100 points, and the test driver made a sensory evaluation with a maximum score of 200 points. The initial grip performance indicates the grip performance of the first to fourth laps, and the latter grip performance indicates the grip performance of the fifth to eighth laps. The larger the value, the better the grip performance.

(Abrasion resistance)
The wear of the tire used in the grip performance evaluation was visually observed, the appearance of the tire of Comparative Example 1 was set at 100 points, and relative evaluation was performed with a maximum score of 200 points. It shows that abrasion resistance is excellent, so that a value is large.

From Table 1, the example using the α-pinene derivative was excellent in performance such as processability, rubber strength, grip performance, and abrasion resistance, despite using a softening agent having a low environmental load. . Furthermore, since it is a softener derived from α-pinene, it was possible to stably obtain excellent performance.

Claims (5)

Look containing a rubber component and α- pinene derivatives,
The α-pinene derivative is a hydroxide of α-pinene, an esterified product of α-pinene, an ether form of α-pinene, a conjugate of α-pinene and an alcohol, a hydrogenated product of terpineol, a hydrogenated product of terpineol. A rubber composition for tires which is at least one selected from the group consisting of an esterified product of terpineol, an esterified product of terpineol hydroxide, and an ether form of terpineol (provided that 0-100 parts by weight of natural rubber, 100 to 0 parts by weight of a polymer (weight ratio of styrene to butadiene (styrene / butadiene) is 23.5 / 76.5, including 7.5 parts by weight of oil per 100 parts by weight of styrene-butadiene copolymer), 0 to 50 parts by weight of 1,4-polybutadiene, 25 to 100 parts by weight of carbon black, 2 to 10 parts by weight of zinc oxide, Tearic acid 1.5-3.0 parts by weight, 2,2'-dithio-bisbenzothiazole 0.5-3.0 parts by weight, pine oil 2-50 parts by weight, tetramethyl disulfide thiuram 0 0.05 to 1.0 part by weight, 0.1 to 4 parts by weight of an antioxidant, and a rubber composition for a polyester cord containing 1.0 to 5.0 parts by weight of sulfur) . The tire rubber composition according to claim 1, wherein the α-pinene derivative has a boiling point of 200 ° C. or higher. The tire rubber composition according to claim 1 or 2, wherein the α-pinene derivative has a viscosity at 20 ° C of 100,000 mPa · s or less. The α-pinene derivatives are terpineol, terpinyl methyl ether, dihydroterpineol, dihydroterpinel acetate, 4- (1′-acetoxy-1′-methylethyl) cyclohexanol acetate, 2- (1-methyl-1- (4-Methyl-3-cyclohexenyl) ethoxy) ethanol, isobornylcyclohexanol, dihydroterpinyloxyethanol, and at least one selected from the group consisting of dihydroterpinylmethyl ethers. 4. The rubber composition for tires according to any one of 3 . The pneumatic tire produced using the rubber composition in any one of Claims 1-4 .