JP4820969B2 - Tire, manufacturing method thereof, and automobile using the same - Google Patents

Description

The present invention relates to a tire excellent in wet performance such as braking performance in snow or rainy weather, hydroplane phenomenon reduction performance and the like and an automobile using the tire.

Currently, tire tread rubber compositions having excellent wet performance have been actively developed for improving braking performance and anti-slip performance in snowy or rainy weather. Known tread rubber compositions having excellent wet performance include those having a hydrophilic surface as a whole and water repellent surfaces as a whole. (For example, see Patent Document 1)

However, in the development of conventional tread rubber, the wet performance is not sufficient.
Japanese Patent Laid-Open No. 09-164809

An object of the present invention is to solve the above problems and achieve the following objects. That is, an object of the present invention is to provide a tire having good wear resistance and excellent wet performance such as braking performance, anti-slip performance, and hydroplane phenomenon reduction performance of an automobile in snow or rainy weather. .

As a result of researching methods for solving the above problems, road surfaces and tires whose surfaces are wet with water have been improved in order to improve wet performance such as braking performance, anti-slip performance, and hydroplane phenomenon reduction performance during snow and rain. We found it important to eliminate the water film between the tread rubbers.

In other words, when the vehicle is running, it is possible to improve the wet performance such as the braking performance, anti-slip performance, and hydroplane phenomenon reduction performance of the vehicle when it is snowing or raining by adding the function of pushing the water on the road surface to the tire tread surface. I found something I could do.

This invention is made | formed based on the said knowledge, and is as follows.
The tire of the first invention is characterized in that fibers or fine particles having a hydrophilic surface and water-repellent inside are mixed as fillers in the tread rubber of the tire.

According to the tire of the first aspect of the present invention, when a vehicle is driven in snowy or rainy weather, a water film interposed between the contact surface of the tire surface and a wet road surface can be automatically excluded, and the braking performance of the vehicle can be reduced. Wet performance such as anti-slip performance and hydroplane phenomenon reduction performance can be improved.

At this time, if a fluororesin fiber or a silicone resin fiber having a hydrophilic surface is used as the fiber having a hydrophilic surface and a water-repellent inside, the adhesion to the raw rubber is improved.

In addition, the surface of the fluororesin fiber whose surface exposed from the tread rubber has been hydrophilized is worn and water-repellent during running, and this water-repellent surface has low surface energy and low friction. Less wear compared to rubber, and part of the water-repellent fiber protrudes from the tread rubber surface with use.

Therefore, the tread rubber surface is covered with fine water-repellent fibers, and the tire contact surface becomes super water-repellent. This makes it convenient to automatically push out and remove the water film intervening between the contact surface of the tire tread surface and the wet road surface when driving a car in snowy or rainy weather.

At this time, if the fiber mixing ratio exceeds 60% by volume, the surface of the tread rubber is almost entirely covered with water-repellent fibers, so that the frictional resistance of the tire against the ground is reduced, and the weather is clear. The braking performance will be worse.

However, if the fiber mixing ratio is 30 to 60% by volume, the tire and the tread rubber surface of the tire get wet when snowing or raining, without substantially impairing the frictional resistance between the tire and the road surface when driving in fine weather. It is convenient to automatically eliminate the water film intervening on the contact surface of the road surface.

Furthermore, when the water droplet contact angle of the contact surface of the tread rubber is 120 degrees or more, it is convenient that the water film interposed on the contact surface between the tread rubber surface and the wet road surface can be almost completely automatically removed.

The tire manufacturing method according to the second aspect of the invention includes a step of kneading a water-repellent fiber whose surface is made hydrophilic to a rubber material to create a tread rubber sheet, a step of attaching to a surface of a green tire, It includes a step of forming and vulcanizing using a mold.

According to the tire manufacturing method of the second aspect of the invention, a tire having high wet performance such as braking performance, anti-slip performance, and hydroplane phenomenon reduction performance can be manufactured and provided with high efficiency.

The automobile of the third invention is characterized in that a tire including water-repellent fibers whose surface is processed to be hydrophilic is mounted in a tread rubber.

According to the vehicle of the third aspect of the invention, even when the road surface is wet with water, such as during snowfall or rain, wet performance such as braking performance, anti-slip performance, and hydroplane phenomenon reduction performance is not impaired. , Improve the safety of the car. In addition, the asphalt road surface is not damaged.

At this time, if the critical surface energy of the tread rubber surface of the tire is set to 15 mN / m or less, the water film interposed between the contact surface of the tire surface and the wet road surface in snow or rain is automatically almost completely completed. It is extremely convenient for safe driving.

As described above, according to the tire of the present invention, when driving an automobile in snowy or rainy weather, a water film interposed between the contact surface of the tire surface and a wet road surface can be automatically excluded, and the braking performance of the automobile It has the effect of improving wet performance such as anti-slip performance and hydroplane phenomenon reduction performance.

In addition, even if the road surface is wet, such as when snowing or raining, the car equipped with this tire will not impair the wet performance such as braking performance, anti-slip performance, hydroplane phenomenon reduction performance, etc. There is an effect to improve.

The present invention can automatically eliminate a water film interposed between the tread rubber surface of a tire and a contact surface of a wet road surface when driving a car in snowy or rainy weather, and the braking performance, anti-slip performance, The present invention provides a tire excellent in wet performance such as a reduction in plain phenomenon.

In addition, the present invention provides a safe vehicle having excellent wet performance such as braking performance, anti-slip performance, and hydroplane phenomenon reduction performance equipped with the tire.

The tire according to the first aspect of the present invention is a tire in which fibers or fine particles having a hydrophilic surface and water-repellent inside are mixed as a filler into at least a tread rubber constituting the tire.

In the tire according to the first aspect of the present invention, when a vehicle is driven in snowy or rainy conditions, a water film intervening between the contact surface of the tire surface and a wet road surface can be automatically excluded, and the braking performance and anti-slip of the vehicle can be eliminated. It has the effect of providing a tire with high wet performance such as performance and hydroplane phenomenon reduction performance.

At this time, if a fluororesin fiber or a silicone resin fiber having a hydrophilic surface is used as a fiber having a hydrophilic surface and a water-repellent inside, the adhesiveness to rubber can be improved.

In addition, the surface of the fiber exposed from the tread rubber becomes water-repellent when the surface is worn during running, and this water-repellent surface has low friction, so there is less wear compared to rubber and the tread is used with use. Projects to the rubber surface.

Therefore, the tread rubber surface is covered with fine water-repellent fibers, and the tire surface becomes super water-repellent. This has the effect of automatically removing the water film present on the contact surface between the tire surface and the wet road surface when driving an automobile during snowfall or rainy weather.

Further, if the fiber volume mixing ratio is set to 30 to 60% by volume ratio, the surface coverage by the water-repellent fibers becomes 30 to 60%, and the friction between the tire and the road surface when traveling in fine weather may be greatly impaired. Absent.

A tire manufacturing method according to a second aspect of the present invention includes a step of kneading a water-repellent fiber having at least a hydrophilic surface processed into a rubber material to form a sheet-like tread rubber material, and a green tire via a base rubber. The process of sticking to the surface of this, and the process of heat-molding and vulcanizing in a metal mold | die are included.

The tire manufacturing method according to the second aspect of the invention has an effect of providing and providing a safety tire having high wet performance such as braking performance, anti-slip performance, and hydroplane phenomenon reduction performance.

The automobile of the third invention is a safety automobile equipped with a tire containing water-repellent fibers whose surface is made hydrophilic in tread rubber.

According to the automobile of the third invention, the wet performance such as braking performance, anti-slip performance, and hydroplane phenomenon reduction performance is not impaired even when the road surface is wet, such as during snowfall or rainy weather. There is an effect that can greatly contribute to driving.

At this time, if the surface energy of the tread rubber surface of the tire is set to 15 mN / m or less, a water film interposed between the contact surface of the tire surface and the wet road surface is automatically formed during running in snow or rain. Since it can be almost completely eliminated, it has the effect of driving more safely.

Hereinafter, embodiments of a tire according to the present invention, a manufacturing method thereof, and an automobile using the tire will be described in detail.
(Embodiment 1)

First, the tire of the first invention will be described together with its manufacturing method (second invention).

Prepare in advance water-repellent fibers (fluorine resin fibers or silicone resin fibers, preferably having a diameter of several to several hundreds of microns and a length of several millimeters. Fine particles may be used as long as the shape is selected). By oxidizing the surface by corona treatment in air or plasma treatment in low-pressure oxygen gas, a fiber having a water repellent inside is formed by forming a hydrophilic layer of about 1 nanometer on the fiber surface. (The shape may be fine, not fibrous.)

Next, rubber composition and reinforcing filler, vulcanizing agent, vulcanization accelerator, vulcanization aid, anti-aging agent, antistatic agent, ozone degradation inhibitor, foaming aid, antioxidant, colorant, Additives such as dispersants, lubricants, softeners, foaming agents, inorganic fillers, etc., and further, the hydrophilic layer formed on the fiber surface is kneaded with water-repellent fibers and heated and extruded. A sheet-like tread rubber composition is prepared.

Thereafter, the sheet-like tread rubber composition is further affixed onto an unvulcanized base that has been separately affixed in advance to the crown portion of the green tire case.

Next, by putting in a predetermined mold and vulcanizing while pressure forming, a tire having an initial water droplet contact angle of 70 to 85 degrees on the tread rubber surface can be produced.

Finally, when the surface of the tire ground contact portion is worn with sandpaper, the water-repellent fibers are exposed, and the tire has a water droplet contact angle of 130 to 150 degrees on the tread rubber surface.

Here, if the fiber volume mixing ratio is set to 30 to 60% by volume ratio, the surface coverage by the water-repellent fibers when using the tire is 30 to 60% due to wear of the rubber composition of the ground contact portion. However, the friction between the tire and the road surface when driving in fine weather will not be so much impaired.

On the other hand, on the surface of the tread rubber in use, fine unevenness is formed by the worn water-repellent fiber, so the water droplet contact angle is 120 degrees (critical surface energy 5-6 mN / m) or more (usually 130- 160 degrees), and when driving in snowy or rainy conditions, the water film interposed between the contact surface of the tire tread and the wet road surface can be almost completely eliminated.

Here, the water droplet contact angle of the tread rubber is absolutely required to be 90 degrees or more in order to impart water repellency, but is 120 degrees or more in order to sufficiently remove the water film. Is preferred.

When the water droplet contact angle is less than 120 degrees, the force to eject the water film sandwiched between the road surface and the tire surface to a portion other than the contact portion is weak, and the wet performance improvement effect is greatly reduced. Incidentally, in the tread rubber of a general tire, the contact angle with water is 70 to 85 °.

On the other hand, the addition amount of the vest must be determined as appropriate depending on the type of the water-repellent fiber to be added. However, if the volume mixing ratio of the fiber exceeds approximately 60% by volume, the friction coefficient of the surface of the contact portion of the tread rubber is greatly impaired. Or rubber strength deteriorates. On the other hand, if it is less than about 30%, the rubber composition itself of the tread rubber is mostly exposed on the surface and the water repellency is greatly deteriorated. Therefore, the mixing ratio seems to be preferably 40 to 50%.

Moreover, the said water-repellent fiber may be used individually by 1 type, and may use 2 or more types together.

Furthermore, the shape of the water-repellent fiber is not necessarily uniform. A diameter of about several to several tens of microns and a length of several tens to several hundreds of microns are easy to handle and have good performance. From this, if it is thin, the fiber strength deteriorates and the tire life is shortened. On the other hand, if it is too thick, the water repellency is greatly reduced even with the same addition amount.

In addition, there is no restriction | limiting in particular about the apparatus, system, conditions, etc. which perform the shaping | molding and vulcanization used for this invention, According to the objective, it can select suitably.
For example, as an apparatus for performing the vulcanization molding, a molding vulcanizer using a mold usually used for vulcanizing a rubber composition for tires may be used. The temperature of the vulcanization molding is usually about 120 to 190 ° C.

The kneading conditions are not particularly limited. The volume to be added to the kneading apparatus, the kneading temperature, the kneading time, the rotational speed of the rotor, the ram pressure, and the type of the kneading apparatus can be appropriately selected according to the purpose.

For example, as the kneading apparatus, there are an intermix, a Banbury mixer, a kneader and the like which are usually used for kneading a rubber composition.

Further, the heating condition is not particularly limited. Various conditions such as the heating temperature, the heating time, and the heating apparatus can be appropriately selected according to the purpose.
For example, as the heating apparatus, a roll machine or the like usually used for heating a rubber composition can be used.

Furthermore, the conditions for the extrusion are not particularly limited, and various conditions such as an extrusion time, an extrusion speed, an extrusion apparatus, and an extrusion temperature can be appropriately selected according to the purpose.
For example, as the extrusion device, an extruder or the like usually used for extrusion of a rubber composition for tires can be used. The extrusion temperature can be determined as appropriate.

Furthermore, a plasticizer such as aroma oil, naphthene oil, liquid polyisoprene rubber, paraffin oil, ester oil or the like, liquid polybutadiene for the purpose of controlling the fluidity of the tread rubber composition during the extrusion. Processability improvers such as liquid polymers such as rubber can be added as appropriate.
In this case, the viscosity of the tread rubber composition before vulcanization can be reduced, the fluidity thereof can be increased, and extrusion can be carried out extremely well.

On the other hand, generally, the WET braking performance is deteriorated when the water film on the road surface is about 1 to 2 mm. In this case, the hydroplane phenomenon does not occur, and the water repellency of the tread block greatly contributes to the WET braking performance.

In the tire produced by the method described above, as shown in FIG. 1 (a), when not in use, the crown portion 1 surface via a base 2, a tread rubber 3 is bonded, year, tread rubber 3 The water-repellent fiber 4 whose inner surface has been processed to be hydrophilic is generally covered with the rubber composition. That is, the surface of the tread rubber portion is in a state where the water-repellent fibers 4 having a hydrophilic surface are hardly exposed.

However, by polishing the ground contact surface of the tire tread for initial use, as shown in FIG. 1B, the rubber composition on the surface of the ground contact portion 3 ′ of the tread rubber is worn, and the surface is A part of the hydrophilic water-repellent fiber is exposed. Furthermore, the surface of the fiber exposed from the tread rubber is hydrophilic and the surface is worn during running to make it water repellent, and this water repellent surface has low friction and therefore wear compared to the rubber composition. There is little and protrudes on the tread rubber surface with use.

Therefore, the tread rubber surface is always covered with the fine water-repellent fiber protrusions 4 'as shown in FIG. Water repellency (water droplet contact angle of 120 degrees or more, usually 130 to 150 degrees) is maintained.

On the other hand, since the block groove interior 5 does not come into contact with the road surface, it hardly wears and is covered with a rubber composition, so that the surface is always hydrophilic at 90 degrees or less.

Therefore, in the tire according to the present invention, when the road surface 6 is wet with water 7 due to snow or rain, the water film interposed at the contact interface 8 between the road surface and the tread rubber is exposed to the exposed repellent surface of the tread block. The water-based fiber quickly pops out to the block groove portion 5, and as shown in FIG. 1C, it is possible to always obtain a substantial effective ground contact area.

Therefore, when a vehicle equipped with such a tire is driven during snowfall or in the rain, an effect of automatically removing a water film present on the contact surface between the tire surface and the snow surface or a wet road surface appears. WET braking performance such as braking performance in the time of rain or rain is improved.

On the other hand, the hydro play phenomenon occurs when the water film is about 5 to 20 mm, and is likely to occur with the running speed and the thickness of the water film. In order to prevent this, it is important how quickly a large amount of water film interposed at the interface between the road surface and the tread block flows out of the interface, and the macro drainage effect greatly contributes to slip prevention.

On the other hand, the side surface and bottom surface of the block groove 5 in the tread block of the present invention, that is, the portion where the water-repellent fiber is not exposed has little water repellency, so the resistance to convection water is small, and the water flowing into the groove Are easy to flow and easy to eliminate. As a result, WET characteristics such as prevention of hydroplane phenomenon during rainy weather are also improved.

Except for the water-repellent fibers or fine particles, there are no particular limitations on the components for blending the tread rubber composition, and examples include those containing a rubber component and other components appropriately selected as necessary.

For example, the rubber component contains at least one diene rubber, and further contains other rubber as necessary. Examples of the diene rubber include natural rubber, polybutadiene rubber, chloroprene rubber, polyisoprene rubber, styrene / butadiene rubber, acrylonitrile / butadiene rubber, and ethylene / propylene / diene copolymer rubber. These may be used individually by 1 type and may use 2 or more types together.

Among these, natural rubber, polyisoprene rubber, and styrene / butadiene rubber polybutadiene rubber are preferable. Examples of the other rubber include fluorine rubber, butyl rubber, silicone rubber, ethylene / propylene copolymer rubber, epichlorohydrin rubber, urethane rubber, and polysulfide rubber. The content of the diene rubber in the rubber component is preferably 90% by weight or more, more preferably 95% by weight or more, and particularly preferably 100% by weight.

As said other component, it can select suitably according to the objective within the range which does not impair the effect of this invention, and a commercial item can be used conveniently.
Examples of the other components include reinforcing fillers, vulcanizing agents such as sulfur, vulcanization accelerators such as dibenzothiazyl disulfide, vulcanization aids, N-cyclohexyl-2-benzothiazyl-sulfonamide, N- Anti-aging agents such as oxydiethylene-benzothiazyl-sulfonamide, zinc oxide, stearic acid, antiozonants, colorants, antistatic agents, dispersants, lubricants, softeners, antioxidants, foaming agents, foaming aids, In addition to additives such as inorganic fillers, various compounding agents usually used in the rubber industry are included.

The reinforcing filler is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include carbon black, silica, and short fibers.

Furthermore, there is no restriction | limiting in particular as said carbon black, A commercial item can be used conveniently. The content of the carbon black in the rubber composition is preferably 5 to 60 parts by weight with respect to 100 parts by weight of the rubber component.

There is no restriction | limiting in particular as said silica, A commercial item can be used conveniently. The content of the silica in the rubber composition is preferably 5 to 60 parts by weight with respect to 100 parts by weight of the rubber component.

There is no restriction | limiting in particular as said short fiber, According to the objective, it can select suitably, For example, inorganic fibers, such as organic fibers, such as a polyamide fiber, polyolefin fiber, and a polyester fiber, glass fiber etc. are mentioned.
(Embodiment 2)

Next, the automobile of the third invention will be described.
The automobile of the third invention is a safety automobile equipped with a tire containing water-repellent fibers whose surface is made hydrophilic in tread rubber.

The automobile equipped with the tire of the present invention includes not only so-called passenger cars but also various vehicles such as trucks and buses.

The tire to which the automobile of the invention is attached includes water-repellent fibers whose surface is made hydrophilic in the tread rubber. There is no restriction | limiting in particular except using the said tire, It can employ | adopt as it is for a well-known vehicle.

As an example of the tire, a pair of bead portions, a carcass connected to the bead portion in a toroidal shape, a tire having a belt and a tread for tightening the crown portion of the carcass, and the like are preferable. Further, the tire mounted on the automobile of the present invention may have a radial structure or a bias structure.

The tread is generally composed of an upper cap portion that directly contacts the road surface and a lower base portion that is disposed in contact with the inside of the tire of the cap portion, and has a so-called cap base structure. In the tire mounted on the automobile of the present invention, it is preferable that at least the cap portion of the tire is formed of the tread rubber composition of the present invention.

Such a vehicle can automatically eliminate a water film interposed between the contact surface of the tire surface and a wet road surface when traveling in snow or rain. As a result, WET braking performance such as braking performance in rainy weather is improved. In addition, WET characteristics such as prevention of hydroplane phenomenon during rainy weather are improved. Of course, in a car equipped with a tire of this structure, there is no problem with running in fine weather. Therefore, the vehicle is safer than the conventional vehicle.

Hereinafter, specific examples of the present invention will be described. In addition, this invention is not limited at all by these Examples.

In advance, tetrafluoroethylene (PTFE) fiber having a diameter of 5 to 10 microns and a length of 1 to 3 mm was purchased, and the surface was corona-treated to make it hydrophilic.
Next, various components shown in Table 1 were weighed and mixed to produce respective tread rubber compositions (Examples 1 to 3 and Comparative Examples), which were preformed into a sheet shape.

Furthermore, each sheet-like tread rubber composition is attached to the surface of a green tire via a base rubber, placed in a mold and molded and vulcanized at 150 ° C., and a tire using the tread rubber composition (size: 205 / 60R15) was made as a prototype.
Then, the following evaluation was performed. The results are shown in Table 2.

The wear resistance was calculated by the following equation by measuring the amount of wear loss using a Lambourn abrasion tester.
Abrasion resistance index = {weight after test of tread rubber of example} / (weight before test of tread rubber of comparative example)} × 100
Therefore, here, the larger the value, the better the wear resistance.

Wet braking performance is as follows: Each prototype tire is mounted on a 1500cc class passenger car, and after running on a straight wet road surface with a depth of 2 to 3 mm while running a test at a speed of 60 km / h, the braking distance is measured. Indexed. Here, the smaller the value, the better the result.

Hydroplane phenomenon reduction performance is achieved by installing each prototype tire on a 1500cc class passenger car and driving it on a wet road surface with a water depth of 15mm while running at a speed of 60km / h. The rotational speed was measured. At this time, when the hydroplane phenomenon occurs, the rotational speed of the driving wheels rapidly increases, but the rotational speed of the non-driving wheels hardly changes. Therefore, the ratio of the rotational speed of the driving wheel to the rotational speed of the non-driven wheel is displayed as an index. Therefore, the smaller the value, the better the result.

In Table 1, SBR # 1500 is styrene-butadiene rubber (SBR # 1500 manufactured by GS), BR01 is cis-1,4-polybutadiene (BR01 manufactured by GS), and NR is natural rubber ( Tech BeeHang RSS # 3) was used.

Carbon black is # 70 Carbon N220 (Asahi Carbon Co., Ltd.), silica is Nipsil AQ (Nihon Silica Industry Co., Ltd.), aroma oil is Diana Process Oil AH-24 (Idemitsu Kosan Co., Ltd.), Stearic acid is LUNAC RS beads (manufactured by Kao Corporation), silane coupling agent is bis-3-triethoxysilylpropyl-tetrasulfide (Si69 manufactured by Degussa AG), and anti-aging agent is NOCRACK 6C (Ouchi Shinsei Chemical Industry ( Co., Ltd.), accelerator 1 is diphenylguanidine (manufactured by Sumitomo Chemical Co., Ltd., Soxinol DG), accelerator 2 is N-cyclohexyl-2-benzothiazyl-1-sulfenamide (manufactured by Ouchi Shinsei Chemical Co., Noxeller) CZ), accelerator 3 is dibenzothiazyl disulfide (Ouchi Shinsei Chemical Co., Ltd., Noxeller DM), respectively. It had.

As is clear from the results in Table 2, the tires of Examples 1 to 3 of the present invention had better wear resistance than the comparative example which is a conventional example.
Further, in the automobiles equipped with the tires of Examples 1 to 3, the wet performance such as the braking performance in the rain and the hydroplane phenomenon reduction performance was improved.

Sectional drawing for demonstrating conceptually the tread part of the tire of this invention. (A) is a cross-section after vulcanization and molding, (b) is a cross-section after initial running, and (c) is a cross-sectional view schematically showing an extruded state of a water film on a road surface during rainy running.

Explanation of symbols

1 Crown 2 Base
3 tread rubber
3 ' tread rubber grounding part 4 water-repellent fiber 4' having a hydrophilic surface 4 'water-repellent fiber projection 5 block groove interior 6 road surface 7 water 8 contact interface between road surface and tread rubber

Claims (6)

A tire characterized in that the tread rubber of the tire includes a fluororesin fiber whose surface is hydrophilized. 2. The tire according to claim 1 , wherein a mixing ratio of a fluororesin fiber having a hydrophilic surface is 30 to 60% in a volume ratio. The tire according to claim 1 or 2, wherein a water droplet contact angle on the tread rubber surface of the tire is 120 degrees or more. A process of creating a tread rubber sheet by kneading fluororesin fibers that have been corona-treated on the surface to make them hydrophilic, a rubber material, a process of sticking to the surface of a green tire, and molding and vulcanization using a mold A method for manufacturing a tire, comprising: An automobile equipped with tires containing fluororesin fibers whose surfaces are hydrophilized on tread rubber. The automobile according to claim 5, wherein the critical surface energy of the tread rubber surface of the tire is 15 mN / m or less.

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