JP6406918B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire.

  Conventionally, various pneumatic tires (hereinafter also simply referred to as tires) in which a decorative portion having an annular or other shaped printing layer is formed on the outer surface of the sidewall portion have been proposed (see, for example, Patent Document 1). .

JP 2013-237292 A

  Here, when the decorative portion having the printed layer as described above is provided on the tire, cracks may occur in the decorative portion due to distortion caused by the deformation of the tire during traveling, and thus the durability of the decorative portion is increased. It is demanded to improve. Moreover, when a tire contacts with a curb stone etc., a printing layer may peel off, Therefore It is calculated | required to improve the damage resistance of the decoration part which has a printing layer.

  This invention is made | formed in view of said subject, and it aims at providing the pneumatic tire which improved the durability of the decoration part of a sidewall part, and external damage resistance.

The gist configuration of the present invention is as follows.
The pneumatic tire of the present invention includes a decorative portion having a printed layer and an inner layer and an outer layer respectively disposed on the inner side and the outer side of the printed layer on the outer surface of the sidewall portion,
The inner layer and the outer layer are formed in a wider range than the formation range of the printing layer,
When the storage elastic modulus of the printed layer is E1 ′, the storage elastic modulus of the inner layer is E2 ′, and the storage elastic modulus of the outer layer is E3 ′,
| E1'-E2 '|> | E2'-E3' |
| E1'-E3 '| >> | E2'-E3' |
It is characterized by satisfying.
According to the pneumatic tire of the present invention, the durability and the damage resistance of the decorative portion of the sidewall portion can be improved.
Here, in this specification, "storage elastic modulus" shall mean what was measured at the temperature of 25 degreeC based on JISK7244.

Here, in the pneumatic tire of the present invention, the inner layer and the outer layer are preferably made of the same material.
According to this configuration, the durability and damage resistance of the decorative portion of the sidewall portion can be further improved, and it is also preferable from the viewpoint of productivity and cost.

Furthermore, in the pneumatic tire of the present invention, the relational expression,
It is preferable that E1 ′ <E2 ′ and E1 ′ <E3 ′ are satisfied.
According to this configuration, the durability of the decorative portion can be further improved.

In the pneumatic tire of the present invention, when the thickness of the printed layer is d1, the thickness of the inner layer is d2, and the thickness of the outer layer is d3,
d1> d2 and d1> d3
It is preferable to satisfy.
According to this configuration, the durability of the decorative portion can be further improved.
In the present specification, the “layer thickness” refers to the thickness of each layer at the maximum thickness position, and is measured by mounting a tire on an applicable rim, filling a specified internal pressure, and no load. Shall. Here, “applicable rim” is an industrial standard that is effective in the region where tires are produced and used. RIM Technical Organization's STANDARDDS MANUAL, TRA (The Tile and Rim Association, Inc.) YEAR BOOK OK, etc. Design Rim). The “specified internal pressure” refers to an air pressure corresponding to the maximum load capacity in the applicable size / ply rating described in the above JATMA YEAR BOOK and the like.

Furthermore, in the pneumatic tire of the present invention, the relational expression,
E2 ′ / E1 ′ ≦ 7.1 and E3 ′ / E1 ′ ≦ 7.1
It is preferable to satisfy.
When satisfy | filling said relational expression, durability of a decoration part can further be improved.

And in the pneumatic tire of the present invention, when the thickness of the printed layer is d1, the thickness of the inner layer is d2, and the thickness of the outer layer is d3,
d2 / d1 ≦ 1/2 and d3 / d1 ≦ 1/2
It is preferable to satisfy.
When satisfy | filling said relational expression, durability of a decoration part can be improved further.

  ADVANTAGE OF THE INVENTION According to this invention, the pneumatic tire which improved the durability and the damage resistance of the decoration part of a sidewall part can be provided.

It is a tire width direction sectional view of a pneumatic tire concerning one embodiment of the present invention. 1 is a side view of a tire / rim assembly in which a pneumatic tire according to an embodiment of the present invention is assembled to a rim. It is a fragmentary sectional view which shows a decoration part and a side wall part roughly.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a tire width direction sectional view of a pneumatic tire according to an embodiment of the present invention. In FIG. 1, only one half of the tire width direction with the tire equatorial plane CL as a boundary is illustrated, but the other half of the tire width direction (not shown) has the same configuration. As shown in FIG. 1, the pneumatic tire 1 includes an annular tread portion 2 that is continuous in the tire circumferential direction and a pair (in FIG. 1) that extends inward in the tire radial direction continuously to both sides of the tread portion 2. The side wall part 3 of only one side is shown, and a pair of bead parts 4 (only one side is shown in FIG. 1) connected to the inner side of the side wall part 3 in the tire radial direction. Here, the internal structure of the tire is not particularly limited, but in the example shown in FIG. 1, the tire 1 is a pair of bead cores 4 a (only one side is shown in FIG. 1) embedded in the bead portion 4. In this example, a belt 6 composed of two belt layers is provided on the outer side in the tire radial direction of the carcass 5 straddling the toroidal shape.

FIG. 2 is a side view of a tire / rim assembly in which a pneumatic tire according to an embodiment of the present invention is assembled to an applied rim. As shown in FIG. 2, the tire 1 is assembled to the application rim R, and includes an annular decorative portion 7 in the illustrated example on the outer surface 3 a of the sidewall portion 3. In the illustrated example, marks M <b> 1 and M <b> 2 made of alphabets are attached to two places on the circumference of the decorative portion 7. In addition, the decoration part 7 may be provided in a part on the periphery of the side wall part 3, for example, can also be provided in the two parts to which the marks M1 and M2 are attached.
Next, FIG. 3 is a partial sectional view schematically showing the decorative portion 7 and the sidewall portion 3. As shown in FIG. 3, the decorative portion 7 includes a printed layer 8 and an inner layer 9 and an outer layer 10 disposed on the inner side and the outer side of the printed layer 8, respectively.

  Here, in this embodiment, the printing layer 8 is formed by applying a paint such as ink to the outer surface 3a of the sidewall portion 3 by, for example, screen printing, inkjet printing, letterpress printing, or other printing. It is.

  The printing layer 8 can be composed of a laminated structure of a white paint layer and a colored paint layer (color other than white) outside the tire. The layer is preferably thicker than the colored paint layer. Such a laminated structure can be applied to all or part of the circumference of the printing layer 8. The colored paint layer may be laminated directly on the surface of the white paint layer, or may be formed via a primer layer. On the other hand, the printing layer 8 can also be composed of only a colored paint layer (a color other than white). In this case, the inner layer 9 is preferably white in order to ensure color developability.

  In the present embodiment, at least the outer layer 10 of the inner layer 9 and the outer layer 10 is a transparent layer so that the printed layer 8 can be seen.

In the pneumatic tire of this embodiment, the inner layer 9 and the outer layer 10 are formed in a wider range than the formation range of the printing layer 8, and the area of the inner layer 9 and the outer layer 10 is the same as that of the printing layer 8. It is larger than the area. In other words, the edge of the inner layer 9 and the edge of the outer layer 10 protrude from the edge of the printed layer 8. Although not shown, the edge of the inner layer 9 and the edge of the outer layer 10 are bonded.
Furthermore, in the pneumatic tire of this embodiment, the magnitude of the difference between the storage elastic modulus E1 ′ of the printed layer 8 and the storage elastic modulus E2 ′ of the inner layer 9 or the storage elastic modulus E3 ′ of the outer layer 10 is the inner layer. 9 is larger than the difference between the storage elastic modulus E2 'of the outer layer 10 and the storage elastic modulus E3' of the outer layer 10. That is, the pneumatic tire of the present embodiment has a relational expression:
| E1'-E2 '|> | E2'-E3' |
| E1'-E3 '| >> | E2'-E3' |
It satisfies.
Hereinafter, the effect of the pneumatic tire of this embodiment is explained.

First, the printing layer 8 is formed with a thickness on the outer surface 3a of the sidewall portion 3 of the tire. That is, a step due to the thickness is formed at the edge of the region where the printing layer 8 is formed. Therefore, when the tire rides on the curb, the step is caught and the printed layer 8 may be peeled off. According to the pneumatic tire of the present embodiment, the print layer 8 is sandwiched between the inner layer 9 and the outer layer 10 in which the formation range is wider than that of the print layer 8 (FIG. 3 is a decoration). The edges of the printed layer 8 are covered by the inner layer 9 and the outer layer 10 and the printed layer 8 is It can suppress that it peels from a part, and can improve the damage resistance of the decoration part 7. FIG.
Here, when the printing layer 8 is simply covered only with the outer layer 10, the side rubber (rubber constituting the sidewall portion 3), the printing layer 8, and the outer layer 10, which are made of different materials, are adjacent to each other. These three layers are deformed differently from each other due to distortion caused by the deformation of the tire, which may cause cracks in the decorative portion 7. On the other hand, in the pneumatic tire of the present embodiment, the printing layer 8 is sandwiched between the inner layer 9 and the outer layer 10 in which the magnitude of the difference in storage elastic modulus is relatively small (that is, the value of the storage elastic modulus is close). Because of the configuration, the adjacent member having a relatively large difference in storage elastic modulus can be limited to a combination of two types of two layers, that is, the side rubber and the inner layer 9, and the printing layer 8 and the outer layer 10. In addition, it is possible to suppress complicated deformation in the decorative portion 7 due to distortion due to deformation of the tire, to suppress generation of cracks in the decorative portion 7, and to improve durability of the decorative portion 7.
Thus, according to the tire of the present embodiment, the durability and the damage resistance of the decorative portion of the sidewall portion can be improved.

  Here, in the pneumatic tire of the present invention, the inner layer 9 and the outer layer 10 are preferably made of the same material. Adhesiveness between the edge of the inner layer 9 and the edge of the outer layer 10 is improved, and the durability and damage resistance of the decorative part 7 of the sidewall part 3 can be further improved. It is because it is preferable also from a viewpoint of property and cost.

Further, in the pneumatic tire of the present invention, the storage elastic modulus E1 ′ of the printing layer 8 is smaller than the storage elastic modulus E2 ′ of the inner layer 9 and the storage elastic modulus E3 ′ of the outer layer 10, that is, It is preferable that E1 ′ <E2 ′ and E1 ′ <E3 ′ are satisfied.
By arranging the soft layer having a low storage elastic modulus in the middle, the decoration part 7 as a whole can easily follow the distortion caused by the deformation of the tire, and the durability of the decoration part 7 can be further improved.

Furthermore, the pneumatic tire of the present invention has a relational expression:
E2 ′ / E1 ′ ≦ 7.1 and E3 ′ / E1 ′ ≦ 7.1
It is preferable to satisfy.
By satisfying the above numerical range, it is possible to improve the durability of the decorative portion 7 so that the rigidity step between the printed layer 8 and the inner layer 9 and the outer layer 10 does not become too large.

Moreover, in this invention, it is preferable to further provide the protective layer which has the storage elastic modulus E4 'larger than the storage elastic modulus E3' of the outer layer 10 on the tire outer side of the outer layer 10. Thereby, the damage resistance of the decoration part 7 can further be improved.
Here, specifically, from the viewpoint of ensuring durability with the printing layer 8 having a low storage elastic modulus while improving the damage resistance with a protective layer having a high storage elastic modulus, the storage elastic modulus E1 of the printing layer 8 is used. 'Is preferably 4.0 × 10 ⁶ (Pa) or less, and the storage elastic modulus E4 ′ of the protective layer is preferably 1.0 × 10 ⁷ (Pa) or more.
On the other hand, so as not too large difference in rigidity in the decorative portion 7, from the viewpoint of ensuring the durability of the decorative portion 7, the storage modulus E1' print layer 8, 5.0 × 10 ⁵ It is preferable to set it to (Pa) or more, and it is preferable that the storage elastic modulus E4 ′ of the protective layer is 5.0 × 10 ⁸ (Pa) or less.

Furthermore, in the pneumatic tire of the present invention, when the storage elastic modulus of the side rubber adjacent to the tire inner side of the decorative portion 7 is E5 ′,
E1 '<E5'
Preferably satisfying
E2 ′ <E5 ′ and E3 ′ <E5 ′
It is further preferable to satisfy
When the above relational expression is satisfied, the printed layer 8, the inner layer 9, and the outer layer 10 can follow the strain of the side rubber particularly when the sidewall portion 3 of the tire is deformed. This is because the durability of the decorative portion 7 can be further improved.

  Here, in the present invention, the material of the printing layer 8 is not particularly limited. For example, an oligomer, a monomer, and a colorant are main components. If necessary, a photopolymerization initiator, an ultraviolet absorber, an oxidation agent are used. An active energy ray-curable ink in which an inhibitor, a light stabilizer, an adhesion promoter, a rheology modifier, a dispersant and the like are blended can be used. And the storage elastic modulus E1 'of the printing layer 8 can be controlled to a predetermined range by adjusting the compounding quantity of said material. More specifically, as a material for the printing layer 8, UF-245 ink series manufactured by DNP Fine Chemical Co., etc. can be used. Further, the material of the protective layer is not particularly limited. For example, a (meth) acrylic acid resin or a resin obtained by modifying this resin with silicone can be used, and in addition to these resins, urethane is further used. It is also possible to use a resin obtained by mixing a base resin or a resin obtained by modifying a carbonate of this resin. More specifically, as a material for the protective layer, a (meth) acrylic acid-based resin or a resin obtained by modifying this resin with silicone includes “OP-SA13”, “OP-SA79”, “OP-” manufactured by DNP Fine Chemical Co., Ltd. Examples of “SA355”, “OP-SA356”, urethane resin, or resin obtained by carbonate modification of this resin include “OP-U354” manufactured by DNP Fine Chemical Co., Ltd. The storage elastic modulus E4 ′ of the protective layer can be controlled within a predetermined range by adjusting the blending amount of the above materials. Furthermore, the material of the inner layer 9 and the outer layer 10 is not particularly limited, but includes, for example, an oligomer and a monomer as main components, and if necessary, a photopolymerization initiator, an ultraviolet absorber, an antioxidant, and a light stabilizer. An active energy ray-curable ink for forming an intermediate layer in which an agent, an adhesion promoter, a rheology modifier and the like are blended can be used. More specifically, as a material for the inner layer 9 and the outer layer 10, a UF-64 ink series manufactured by DNP Fine Chemical Co., etc. can be used. The storage elastic moduli E2 ′ and E3 ′ of the inner layer 9 and the outer layer 10 can be controlled within a predetermined range by adjusting the blending amount of the above materials. As the active energy rays, α rays, γ rays, X rays, ultraviolet rays, electron beams and the like can be used.

In the pneumatic tire of the present invention, the thickness d1 of the printed layer 8 is greater than the thickness d2 of the inner layer 9 and the thickness d3 of the outer layer 10, that is,
It is preferable that d1> d2 and d1> d3 are satisfied.
This is because by increasing the thickness of the soft layer having a low storage elastic modulus, it becomes easier to follow the distortion caused by the deformation of the tire, and the durability of the decorative portion 7 can be further improved.

Furthermore, in the pneumatic tire of the present invention, the ratio d2 / d1 and the ratio d3 / d1 are expressed by the relational expression:
d2 / d1 ≦ 1/2 and d3 / d1 ≦ 1/2
It is preferable to satisfy.
By satisfying the above relational expression, strain due to deformation of the tire can be absorbed by the printing layer 8 having a small storage elastic modulus, and thus the durability of the decorative portion 7 can be further improved.

  Specifically, in order to make the durability of the decorative portion 7 and the damage resistance more compatible, the thickness d1 of the printing layer 8 is preferably 40 μm or less, and the thickness d2 of the inner layer 9 and the outer layer The thickness d3 of 10 is preferably 10 to 20 μm.

In the pneumatic tire of the present invention, the concealment rate of the inner layer 9 and the outer layer 10 is preferably smaller than the concealment rate of the printing layer 8.
This is because by reducing the concealment ratio of the inner layer 9 and the outer layer 10, it is possible to form a catch due to microscopic unevenness and further improve the adhesiveness. Further, when the concealment rate is low, a region where the paint is not applied microscopically is formed, so that the distortion can be released and the durability of the decorative portion 7 can be further improved. Here, the “hiding ratio” means the paint area per unit area of the tire surface, and is obtained by performing image processing using a microscope, for example, and measuring the area where the paint is applied. Can do.
That is, while the inner layer 9 and the outer layer 10 are formed in a wider range than the formation range of the printing layer 8, when viewed microscopically in a certain unit area of the sidewall portion 3, the coating area is the printing layer. It is preferably less than 8 paint areas.

  In order to confirm the effect of the present invention, a tire according to Invention Examples 1 to 6 and a tire according to Comparative Example 1 were prototyped, and a test for evaluating durability and damage resistance of the decorative portion was performed. Each of the tires has a common internal structure as shown in FIG. 1 and includes a decorative portion having a printed layer, an inner layer, and an outer layer on the outer surface of the sidewall portion. The specifications of each tire are shown in Table 1 below, and the specifications not shown in Table 1 are common to each tire.

<Durability of decorative parts>
Each of the above tires was incorporated into an applicable rim, filled with a specified internal pressure, and mounted on the vehicle. And the test which measures the crack extension length which generate | occur | produces in a decoration part after driving | running | working 20,000 km with a real vehicle was done, and durability of the decoration part was evaluated. The evaluation is expressed as an index when the tire according to Comparative Example 1 is set to 100, and the larger the value, the better the durability of the decorative portion.

<Trade resistance of decorative parts>
For each of the above tires, a test for scratching the decorative portion with a coin under a load condition of 1200 g was performed, and the damage resistance of the decorative portion was evaluated. The evaluation is expressed as an index when the tire according to Comparative Example 1 is set to 100, and the larger the value, the better the damage resistance of the decorative portion.
These evaluation results are shown in Table 1 below.

  As shown in Table 1, it can be seen that the tires according to Invention Examples 1 to 6 are superior in durability and damage resistance of the decorative portion 7 as compared with the tire according to Comparative Example 1. Further, it can be seen that Invention Example 1 in which the inner layer 9 and the outer layer 10 are made of the same material is superior to the Invention Example 2 in durability and damage resistance of the decorative portion 7. Furthermore, Invention Example 1 in which the storage elastic modulus E1 ′ of the printed layer 8 is smaller than the storage elastic modulus E2 ′ of the inner layer 9 and the storage elastic modulus E3 ′ of the outer layer 10 is more durable than the inventive example 3. It turns out that it is excellent. In addition, it can be seen that Invention Example 1 in which the thickness d1 of the printed layer 8 is thicker than the thickness d2 of the inner layer 9 and the thickness d3 of the outer layer 10 is superior in durability of the decorative portion 7 to the Invention Example 4. . Furthermore, it can be seen that Invention Example 1 that satisfies E2 ′ / E1 ′ ≦ 7.1 and E3 ′ / E1 ′ ≦ 7.1 is superior to Invention Example 5 in durability of the decorative portion 7. Furthermore, it can be seen that Invention Example 1 satisfying d2 / d1 ≦ 1/2 and d3 / d1 ≦ 1/2 is superior to Invention Example 6 in durability of the decorative portion 7.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 3 Side wall part 3a Outer surface of side wall part 4 Bead part 4a Bead core 5 Carcass 6 Belt 7 Decoration part 8 Print layer 9 Inner layer 10 Outer layer

Claims (4)

Provided on the outer surface of the sidewall portion is a decorative portion having a printed layer and an inner layer and an outer layer disposed on the inside and outside of the tire of the printed layer, respectively.
The inner layer and the outer layer are formed in a wider range than the formation range of the printing layer,
When the storage elastic modulus of the printed layer is E1 ′, the storage elastic modulus of the inner layer is E2 ′, and the storage elastic modulus of the outer layer is E3 ′,
| E1'-E2 '|> | E2'-E3' |
| E1'-E3 '| >> | E2'-E3' |
Meet the,
When the thickness of the printed layer is d1, the thickness of the inner layer is d2, and the thickness of the outer layer is d3,
d2 / d1 ≦ 1/2 and d3 / d1 ≦ 1/2
The filling,
A protective layer having a storage elastic modulus E4 ′ larger than the storage elastic modulus E3 ′ of the outer layer on the outer side of the tire of the outer layer;
The pneumatic tire according to claim 1, wherein a concealing rate of the inner layer and the outer layer is smaller than a concealing rate of the printed layer .   The pneumatic tire according to claim 1, wherein the inner layer and the outer layer are made of the same material. Relational expression,
E1 ′ <E2 ′ and E1 ′ <E3 ′
The pneumatic tire according to claim 1 or 2, satisfying Relational expression,
E2 ′ / E1 ′ ≦ 7.1 and E3 ′ / E1 ′ ≦ 7.1
The pneumatic tire according to any one of claims 1 to 3 , wherein the pneumatic tire is satisfied.

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