JP2008050431A - Tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive tire having excellent durability, capable of suppressing the reduction of complex modulus of elasticity by temperature increase, and capable of improving steering stability in wide range of speeds. <P>SOLUTION: The tire is obtained by using a rubber composition containing 0.5-40 pts.wt. wood flour and 0.5-20 pts.wt. curable resin based on 100 pts.wt. rubber component. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tire.

  In recent years, in addition to the remarkable enhancement of equipment and performance of automobiles, the road network has been expanded and developed, so that tires have always been required to have stable handling stability, particularly high stability during high-speed driving. In order to improve the steering stability, it is known that the rigidity of the tread portion or the bead portion may be increased.

  For example, as a technique for increasing the rigidity of the bead part, a method is known in which a large amount of carbon black and a phenol-based thermosetting resin are used in a bead apex blend for reinforcing the bead part. However, as the carbon black is filled, the Mooney viscosity increases and the processability deteriorates, and when a phenol-based thermosetting resin is used, there is a problem of softening at the time of use at a high temperature.

  As a method for increasing the rigidity of the bead portion, a method of filling paper fibers is also known. However, in order to disperse the paper fiber in the rubber, it is necessary to ensure a long kneading time, which causes a problem that the cost is increased and the productivity is deteriorated.

  Patent Document 1 discloses a hard rubber composition containing a predetermined amount of an additive mainly composed of a rubber component and a paper component. However, what is disclosed in this document is used for pipes, packings, containers, etc., and is not intended to be applied to tires, and is filled with a large amount of additives mainly composed of paper components. For this reason, in order to ensure dispersibility, the kneading time has to be lengthened, so that there is a problem that the processability is poor.

JP 2001-26679 A

  An object of the present invention is to provide an inexpensive tire that is excellent in durability, can suppress a decrease in complex elastic modulus due to a temperature rise, can improve steering stability in a wide speed range, and is inexpensive. To do.

  The present invention relates to a tire using a rubber composition containing 0.5 to 40 parts by weight of wood powder and 0.5 to 20 parts by weight of a curable resin with respect to 100 parts by weight of a rubber component.

  According to the present invention, the rubber component, the wood powder, and the curable resin are contained in predetermined amounts, so that the durability is excellent, the decrease in the complex elastic modulus due to the temperature rise can be suppressed, and the steering stability in a wide speed range In addition, an inexpensive tire can be provided.

  The tire of the present invention contains a rubber composition.

  The rubber composition contains a rubber component, wood powder, and a curable resin.

  The rubber component is not particularly limited. For example, natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), butyl rubber (IIR), halogenated butyl rubber (X-IIR) Chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), ethylene propylene diene rubber (EPDM), halides of copolymers of isomonoolefin and paraalkyl styrene, and the like. You may use, and may use it in combination of 2 or more type. Among them, NR and SBR are preferable, and NR and SBR are more preferable because NR is excellent in strength and SBR can improve rigidity.

  The wood flour is not particularly limited, and examples thereof include those obtained from common natural wood such as persimmon, pine, cedar, hinoki and lawan. These wood flours may be used alone. You may use combining more than a seed.

  The wood flour is preferably fibrous. In addition, by improving the rigidity in the circumferential direction of the tire while maintaining the rigidity in the radial direction of the tire, it is possible to improve steering stability and riding comfort in a highly balanced manner. It is preferable to orient.

  The method of forming the wood powder is different in each stage of coarse pulverization, medium pulverization, and fine pulverization, but there is no particular limitation, and the natural wood and building waste materials are pulverized using a crusher such as a roll mill or an impact mill. Methods.

  The average fiber diameter (D) of the wood flour is preferably 0.5 μm or more, and more preferably 1 μm or more. When D of wood powder is less than 0.5 μm, there is a tendency that a sufficient reinforcing effect cannot be obtained. Further, D of the wood flour is preferably 100 μm or less, more preferably 80 μm or less, and further preferably 60 μm or less. When D of wood powder exceeds 100 micrometers, there exists a tendency for the poor dispersion | distribution of wood powder in a rubber composition, and the nonuniformity of the physical property of a rubber composition.

  When using fibrous wood flour, the average fiber length (L) of wood flour is preferably 10 μm or more, and more preferably 50 μm or more. If the L of wood flour is less than 10 μm, there is a tendency that a sufficient reinforcing effect cannot be obtained. Further, the L of the wood flour is preferably 1000 μm or less, and more preferably 900 μm or less. If the L of wood powder exceeds 1000 μm, poor dispersion of wood powder in the rubber composition and non-uniform physical properties of the rubber composition tend to be caused.

  When using fibrous wood flour, the average aspect ratio (L / D) of the wood flour is preferably 10 or more, and more preferably 20 or more. When the average aspect ratio of the wood flour is less than 10, there is a tendency that a sufficient reinforcing effect cannot be obtained. The average aspect ratio of the wood flour is preferably 2000 or less, and more preferably 1800 or less. When the average aspect ratio of the wood powder exceeds 2000, there is a tendency that poor dispersion of the wood powder in the rubber composition and non-uniform physical properties of the rubber composition are caused.

  The moisture content of the wood flour is preferably 10% by weight or less, and more preferably 8% by weight or less. If the moisture content of the wood flour exceeds 10% by weight, the dehydration time becomes longer and the productivity tends to decrease. In addition, if the dehydration treatment is not performed, there is a tendency that accurate measurement of wood flour cannot be performed.

  The content of wood flour is 0.5 parts by weight or more, preferably 1 part by weight or more with respect to 100 parts by weight of the rubber component. When the content of the wood powder is less than 0.5 parts by weight, the effect of adding the wood powder is small. Further, the content of the wood flour is 40 parts by weight or less, preferably 35 parts by weight or less. When the content of the wood flour exceeds 40 parts by weight, the strength decreases.

  Examples of the curable resin include phenol-based thermosetting resins such as alkylphenol resins, oil-modified phenol resins, and cashew-modified phenol resins. These curable resins may be used alone or in combination of two or more. You may use it in combination. Among these, cashew-modified phenol resin is more preferable because of its high strength.

  The content of the curable resin is preferably 0.5 parts by weight or more and more preferably 1 part by weight or more with respect to 100 parts by weight of the rubber component. If content of curable resin is less than 0.5 weight part, there exists a tendency for the effect by adding curable resin to be small. Moreover, 20 weight part or less is preferable and, as for content of curable resin, 15 weight part or less is more preferable. When the content of the curable resin exceeds 20 parts by weight, the workability tends to deteriorate and the cost tends to increase.

  In addition, the rubber composition may contain a reinforcing filler.

  The reinforcing filler is not particularly limited, and examples thereof include carbon black, silica, calcium carbonate, aluminum hydroxide, clay, talc, and alumina. These reinforcing fillers are not particularly limited and may be used alone. May be used in combination of two or more, but carbon black and / or silica is particularly preferable.

  There is no restriction | limiting in particular as carbon black, For example, what is normally used in tire industry, such as SAF, ISAF, IISAF, HAF, FEF, GPF, can be used.

  Silica includes those prepared by a dry method or a wet method, but is not particularly limited.

  When the rubber composition contains a reinforcing filler, the content of the reinforcing filler is preferably 30 parts by weight or more and more preferably 40 parts by weight or more with respect to 100 parts by weight of the rubber component. When the content of the reinforcing filler is less than 30 parts by weight, the durability tends to decrease. The reinforcing filler content is preferably 140 parts by weight or less, and more preferably 120 parts by weight or less. When the content of the reinforcing filler exceeds 140 parts by weight, the workability tends to deteriorate.

  In addition to the rubber component, wood powder, curable resin and reinforcing filler, the rubber composition includes compounding agents usually used in the tire industry, such as oil, wax, various anti-aging agents, and tackifying resins. Further, vulcanizing agents such as stearic acid, zinc oxide and sulfur, various vulcanization accelerators and the like may be appropriately contained as required.

The rubber composition has a complex elastic modulus (E ^* ) at 70 ° C. of preferably 10 MPa or more, and more preferably 12 MPa or more. When E ^{* at} 70 ° C. is less than 10 MPa, steering stability tends to deteriorate. Further, E ^{* at} 70 ° C. is preferably 300 MPa or less, and more preferably 280 MPa or less. When E ^{* at} 70 ° C. exceeds 300 MPa, riding comfort tends to deteriorate.

E ^* at 100 ° C. of the rubber composition is preferably 10 MPa or more, and more preferably 12 MPa or more. When E ^{* at} 100 ° C. is less than 10 MPa, steering stability tends to deteriorate. Further, E ^{* at} 100 ° C. is preferably 300 MPa or less, and more preferably 280 MPa or less. When E ^{* at} 100 ° C. exceeds 300 MPa, riding comfort tends to deteriorate.

  The tire of the present invention can be produced by a usual method. That is, the rubber composition in which the compounding agent is appropriately blended as necessary is formed into the shape of each member of a tire in an unvulcanized state and bonded to form an unvulcanized tire, and the unvulcanized tire The tire can be manufactured by heating and pressing.

  When manufacturing the tire of the present invention, the member using the rubber composition is not particularly limited, such as a tread, a bead apex, a sidewall, a clinch, etc., but is suitable for making a highly rigid compound. For reasons, bead apex is preferred.

  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 together.
Natural rubber: RSS # 3 (made in Thailand)
Styrene butadiene rubber (SBR): SBR1502 manufactured by Sumitomo Chemical Co., Ltd.
Carbon black: Dia Black H (N330) manufactured by Mitsubishi Chemical Corporation
Silica: Ultrazil VN3 manufactured by Degussa Huls
Silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) manufactured by Degussa Huls Co., Ltd.
Wood flour: Cellulosin No. manufactured by Casino Co., Ltd. 100 (material: wrinkle, shape: fibrous, average fiber diameter: 25 μm, average fiber length: 500 μm, average aspect ratio: 20, moisture content: 5% by weight)
Paper fiber: Mill Five # 100 (average fiber diameter: 10 μm, average fiber length: 1000 μm, average aspect ratio: 100) manufactured by Sankyo Seiko Co., Ltd.
Curable resin: Sumitrite resin PR12686 (cashew oil modified phenolic resin) manufactured by Sumitomo Durez Co., Ltd.
Aroma oil: Diana Process PS32 manufactured by Idemitsu Kosan Co., Ltd.
Wax: Sannoc Wax anti-aging agent manufactured by Ouchi Shinsei Chemical Co., Ltd .: Ozonon 6C (N-1,3-dimethylbutyl-N′-phenyl-p-phenylenediamine) manufactured by Seiko Chemical Co., Ltd.
Tackifying resin: SP1068 manufactured by Nippon Shokubai Co., Ltd.
Stearic acid: Tungsten zinc oxide manufactured by Nippon Oil & Fats Co., Ltd .: Ginseng R manufactured by Toho Zinc Co., Ltd.
Sulfur: Sulfur vulcanization accelerator NS manufactured by Tsurumi Chemical Co., Ltd. NS: Noxeller NS (N-tert-butyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinsei Chemical Co., Ltd.
Vulcanization accelerator H: Noxeller H (hexamethylenetetramine) manufactured by Ouchi Shinsei Chemical Co., Ltd.

Examples 1-7 and Comparative Examples 1-8
In accordance with the formulation shown in Tables 1 and 2, using a 1.7 L Banbury mixer, chemicals other than sulfur and a vulcanization accelerator were kneaded for 4 minutes at 150 ° C. to obtain a kneaded product. Next, using a biaxial roll, sulfur and a vulcanization accelerator were added to the obtained kneaded product and kneaded for 4 minutes at 80 ° C. to obtain an unvulcanized rubber composition. Furthermore, the obtained unvulcanized rubber composition was press vulcanized for 35 minutes under the conditions of 150 ° C. and 25 kgf to prepare vulcanized rubber compositions of Examples 1 to 7 and Comparative Examples 1 to 8. Examples 1 to 6 and Comparative Examples 1 to 6 (Table 1) are bead apex rubber compositions, and Example 7 and Comparative Examples 7 to 8 (Table 2) are base tread rubber compositions. is there.

(Processability)
In the rubber compositions of Examples 1 to 6 and Comparative Examples 1 to 6, a test piece having a predetermined size was prepared from the unvulcanized rubber composition, and according to JIS K 6300 “Testing method for unvulcanized rubber”. Using a Mooney viscosity tester manufactured by Shimadzu Corporation, rotating a small rotor under a temperature condition of 130 ° C. heated by preheating for 1 minute, an unvulcanized rubber composition after 4 minutes The Mooney viscosity was measured and the Mooney viscosity of Examples 1 to 6 and Comparative Examples 2 to 5 was displayed as an index by setting the workability index of Comparative Example 1 to 100 by the following formula.
(Processability index) = (Mooney viscosity of Comparative Example 1) / (Mooney viscosity of each formulation) × 100

(Complex modulus)
The obtained vulcanized rubber composition was molded into a vulcanized rubber test piece having a size of 4 mm × 30 mm × 1.5 mm, and an initial strain of 10% and dynamic strain were measured using a viscoelastic spectrometer manufactured by Iwamoto Seisakusho Co., Ltd. The complex elastic modulus (E ^* ) of each vulcanized rubber specimen at 70 ° C. and 100 ° C. was measured under the conditions of ± 1% and a frequency of 10 Hz. And the results were calculated (E ^* in E ^* / 100 ° C. at 70 ° C.) reduction rate of E ^*. In addition, it shows that the fall rate of E ^* by temperature rise can be suppressed, so that the fall rate of E ^* is so small.

(Maneuvering stability at medium and low speeds)
The unvulcanized rubber composition was molded into a bead apex shape in Examples 1 to 6 and Comparative Examples 1 to 6, and a base tread shape in Examples 7 and 7 to 8, and other tire members were formed. Along with this, an unvulcanized tire was formed. Further, the test tires (size: 195 / 65R15) of Examples 1 to 7 and Comparative Examples 1 to 8 were manufactured by press vulcanizing the unvulcanized tire for 35 minutes under the conditions of 150 ° C. and 25 kgf. .

  The manufactured tires are mounted on a car, run at 40-100 km / h on a dry asphalt test course, and steering stability is evaluated by a feeling test of steering wheel response, rigidity and grip by a test driver. Went. The evaluation was made on a 5-point scale (5: very good, 4: good, 3: normal, 2: slightly inferior, 1: inferior), and Comparative Example 1 was taken as 100, which was displayed as an index. Moreover, it shows that it is excellent in the handling stability at the time of medium and low speed, so that a numerical value is large.

(Maneuvering stability at high speed)
Except for increasing the speed to 200 km / h, the driving stability of the lane changeability, steering response and rigidity feeling by the test driver is the same as the driving stability at medium and low speeds. Evaluation was performed. The evaluation was made on a 5-point scale (5: very good, 4: good, 3: normal, 2: slightly inferior, 1: inferior), and the average value of the three drivers was calculated. The index was expressed as 100. Moreover, it shows that it is excellent in the steering stability at high speed, so that a numerical value is large.

(durability)
The produced test tire was placed in an oven at 80 ° C. for one week, and then was run at 30000 km at an speed of 80 km / h under conditions of an internal pressure of 200 kPa and a load of 340 kgf (about 3334.278 N). At this time, if the tire could be completed without being damaged, it was judged as acceptable (◯), and if the tire was damaged and could not be completed, it was judged as unacceptable (x).

  Table 1 shows the evaluation results of the above tests for the bead apex rubber composition.

  Comparative Example 1 is a conventional rubber composition for bead apex that does not contain wood flour and contains a curable resin.

  In Examples 1 to 6 containing a predetermined amount of wood flour and curable resin, the durability is excellent, the decrease in the complex elastic modulus due to the temperature rise can be suppressed, and the steering stability in a wide speed range can be improved. did it. In addition, since cheap wood powder was used, the tire could be manufactured more inexpensively.

  In Comparative Example 2, the durability deteriorated because the content of the wood powder was too much.

  In Comparative Example 3, the durability deteriorated because the content of the curable resin was too large.

  In Comparative Examples 4 and 5, since no curable resin was contained, durability was deteriorated and steering stability was lowered. In particular, in Comparative Example 4, since the wood powder was not contained, the steering stability was remarkably lowered.

  Table 2 shows the evaluation results of the above test on the rubber composition for base tread.

  Comparative Example 7 is a conventional rubber composition for base treads that does not contain wood flour and curable resin.

  In Example 7 containing a predetermined amount of wood flour and curable resin, the durability was excellent, the decrease in the complex elastic modulus due to the temperature increase could be suppressed, and the steering stability in a wide speed range could be improved. . In addition, since cheap wood powder was used, the tire could be manufactured more inexpensively.

  In Comparative Example 8, since wood powder was not contained, it was not possible to suppress a decrease in complex elastic modulus due to a temperature rise.

Claims (1)

For 100 parts by weight of rubber component,
A tire using a rubber composition containing 0.5 to 40 parts by weight of wood powder and 0.5 to 20 parts by weight of a curable resin.