JP2014088120A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of contributing to reduction in the amount used of oil resources without impairing performances required for a pneumatic tire by using an organic fiber material instead of organic fibers such as PA66 which have been conventionally used as a reinforcing material of a pneumatic tire.SOLUTION: There is provided a pneumatic tire provided with a reinforcing layer reinforced with an organic fiber cord. The organic fiber cord is made of a polyamide composed of a dicarboxylic acid (A) having 7 or more and 11 or less carbon atoms and a diamine (B).

Description

  The present invention relates to a pneumatic tire (hereinafter, also simply referred to as “tire”), and more particularly, to a pneumatic radial tire for a passenger car according to an improvement of a reinforcing material.

  Conventionally, twisted cords of organic fibers such as polyamide such as PA66 have been mainly used as a reinforcing material used for a belt reinforcing layer of a radial tire for passenger cars.

  On the other hand, in recent years, there has been a demand for a shift from petroleum resource materials to non-oil resource materials in the industrial world from the viewpoint of soaring oil resource prices and contributions to a sustainable society. A proposal has been made to use this rayon for a carcass or a belt reinforcing layer (see, for example, Patent Document 1). However, since rayon has a high elastic modulus, if it is used in a belt reinforcement layer, the deformation of the tire is greatly suppressed, the ride comfort is deteriorated, and more moisture is absorbed, resulting in a decrease in strength and adhesiveness. Since it is easy to cause, it is necessary to control moisture in the manufacturing process, which has been a cause of increasing the manufacturing cost.

JP 2011-136670 A (Claims etc.)

  As mentioned above, in recent years, in order to reduce the amount of petroleum resources used, it has been studied to apply non-petroleum resource materials as tire materials without impairing the performance required for tires, but it is still sufficient. There was no such technology.

  Accordingly, an object of the present invention is to provide a pneumatic tire that can contribute to a reduction in the amount of oil resources used while ensuring the performance required for the tire.

  As a result of intensive studies, the present inventor has found that the above-mentioned problems can be solved by using a polyamide comprising a specific dicarboxylic acid and a diamine as a tire reinforcing material, and has completed the present invention.

That is, the present invention is a pneumatic tire including a reinforcing layer reinforced with an organic fiber cord,
The organic fiber cord is made of polyamide composed of a dicarboxylic acid (A) having 7 to 11 carbon atoms and a diamine (B).

  In the tire of the present invention, the dicarboxylic acid (A) is preferably made of a non-fossil raw material, and more preferably terephthalic acid or sebacic acid made of a non-fossil raw material. Moreover, it is also preferable that the said diamine (B) is a C4-C10 thing.

  According to the present invention, the above configuration makes it possible to realize a pneumatic tire that can contribute to a reduction in the use amount of petroleum resources while ensuring the performance required for the tire. .

It is a width direction sectional view showing an example of the pneumatic tire of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The pneumatic tire of the present invention includes a reinforcing layer reinforced with an organic fiber cord, and the organic fiber cord is composed of a dicarboxylic acid (A) having 7 to 11 carbon atoms and a diamine (B). It is characterized in that it is made of polyamide.

  Conventionally, polyamides using adipic acid having 6 carbon atoms as a raw material dicarboxylic acid have been used as tire reinforcing materials. In the present invention, dicarboxylic acid (A) having 7 to 11 carbon atoms is used as a raw material. As a result, the amount of petroleum resources used can be reduced while ensuring the performance required for tires. Specifically, the elasticity modulus of the obtained polyamide fiber falls by using dicarboxylic acid with more carbon number than before. Therefore, according to the present invention, for example, by applying the reinforcing layer to the belt reinforcing layer, it is possible to reduce rolling resistance in addition to ensuring durability and riding comfort.

  The dicarboxylic acid (A) used in the present invention has 7 to 11 carbon atoms, preferably 7 to 10 carbon atoms. Specific examples of the dicarboxylic acid (A) having 7 to 11 carbon atoms include pimelic acid, suberic acid, terephthalic acid, azelaic acid, and sebacic acid.

  Moreover, in this invention, it can contribute to the reduction of the usage-amount of petroleum resources by using what consists of a non-fossil raw material as dicarboxylic acid (A), It is preferable. As the dicarboxylic acid derived from non-fossil raw materials, for example, known plant-derived terephthalic acid, sebacic acid, and the like can be used, and among them, sebacic acid is preferable as the dicarboxylic acid to be condensed with diamine. Among these, terephthalic acid derived from non-fossil raw materials can be synthesized using bioisobutanol as a raw material, for example, by the method disclosed in WO2011 / 085223A1. Further, sebacic acid derived from non-fossil raw materials can be produced using castor oil as a raw material.

  In the present invention, the diamine (B) to be condensed with the dicarboxylic acid is not particularly limited, and putrescine, cadaverine, hexamethylene diamine, octamethylene diamine, decamethylene diamine and the like can be appropriately mixed and used. Among these, diamines having 4 to 10 carbon atoms are preferable, and for tire cords, for example, putrescine, hexamethylenediamine and decamethylenediamine are preferable.

  In the present invention, the non-fossil raw material ratio is 50% by mass by using polyamide composed of the dicarboxylic acid (A) having 7 to 11 carbon atoms and the diamine (B) as the organic fiber cord used for the reinforcing layer. As described above, in particular, the amount can be 50 to 100% by mass, and the tire can be vulcanized without lowering the vulcanization temperature.

  In the tire of the present invention, the desired effect of the present invention can be obtained as long as the tire includes a reinforcing layer reinforced with an organic fiber cord using the polyamide, and other points are particularly limited. Is not to be done.

  FIG. 1 is a cross-sectional view in the width direction showing an example of the pneumatic tire of the present invention. The pneumatic tire of the present invention shown in the figure has a carcass 2 made of a single carcass ply extending in a toroid shape between a pair of bead cores 1 embedded in a pair of left and right bead portions 11, respectively, and a crown thereof. Two belt layers 3a and 3b are provided on the outer side in the tire radial direction. Further, a cap layer 4 and a layer layer 5 are disposed outside the belt layers 3a and 3b in the tire radial direction.

  In the present invention, as the reinforcing layer reinforced with the organic fiber cord using the polyamide, each member reinforced with the organic fiber cord, such as a carcass ply, a cap layer, a layer layer, and an insert (not shown). Can be mentioned. In the present invention, the reinforcing layer reinforced with the organic fiber cord using the polyamide may be applied to any or all of the respective members of the tire. It is more useful when applied to a belt reinforcing layer composed of a cap layer and / or a layer layer that plays a role of suppressing deformation. The detailed conditions such as the cord diameter and the number of driving of the organic fiber cord in the reinforcing layer according to the present invention can be appropriately set according to the tire size and the like as desired, and are not particularly limited. Absent.

  In the present invention, the carcass 2 is one in the illustrated example, but may be two or more, and preferably one or two. As such carcass 2, when a reinforcing layer reinforced with an organic fiber cord using polyamide is not applied, any conventionally known organic fiber cord may be used, but the amount of petroleum resources used is reduced. Is preferably a cord made of cellulose-derived fibers. Examples of cellulose fibers include rayon, lyocell, and cupra.

  In the present invention, the belt layers 3a and 3b are formed by rubber-covering a plurality of steel cords arranged at an angle of, for example, 15 to 40 ° with respect to the tire circumferential direction. Although it is two sheets, three sheets or more may be sufficient, for example, it can provide by 2-4 sheets.

  Furthermore, in the present invention, the belt reinforcing layer composed of the cap layer 4 and / or the layer layer 5 is necessarily essential when the reinforcing layer reinforced by the organic fiber cord using the polyamide is applied to a carcass ply or an insert. is not. The cap layer 4 and the layer layer 5 are both rubberized organic fiber cords arranged substantially parallel to the tire circumferential direction. As shown in the figure, the cap layer 4 includes the belt layer 3a, At least one layer is disposed over the entire width of 3b, and at least one layer layer 5 is disposed in both end regions of the belt layers 3a and 3b.

  Further, as shown in the drawing, a bead core 1 is embedded in each of the pair of bead portions 11 of the tire of the present invention, and the carcass 2 is usually folded around the bead core 1 from the inside to the outside of the tire and locked. Further, a bead filler 6 is disposed outside the bead core 1 in the tire radial direction. Furthermore, a tread portion 12 is disposed on the outer periphery of the crown portion of the belt layers 3 a and 3 b, and a sidewall portion 13 is disposed on the side portion of the carcass 2.

  Furthermore, a tread pattern is appropriately formed on the surface of the tread portion 12, and an inner liner (not shown) is formed on the innermost layer. Furthermore, in the tire of the present invention, as the gas filled in the tire, normal or air having a changed oxygen partial pressure, or an inert gas such as nitrogen can be used.

Hereinafter, the present invention will be described in more detail with reference to examples.
A pneumatic tire with a tire size of 205 / 65R15 was produced according to the following. Each test tire has one carcass ply (rayon, 1840 dtex / 3, twist number 40 × 40/10 cm, driving number 80/10 cm, angle with respect to tire width direction: 0 °), and a steel belt layer (1 × 5 × 0.25 mm, driving number 80/10 cm, angle with respect to tire width direction: ± 70 ° and cross arrangement) were two. Further, on the outside of the belt layer, one cap layer as a belt reinforcing layer (number of drivings: 100/10 cm, angle with respect to the tire width direction: 90 °) over the entire width and under the conditions shown in the following table. Arranged. The results of evaluation according to the following for each of the obtained test tires are also shown in the following table.

<High speed durability>
Each test tire was assembled on a rim and run at a load of 150% of the maximum load condition specified by JATMA. The speed was increased by 10 km / h every hour, and the speed at the time of failure was measured. The results are shown as an index with the speed of the conventional example as 100. The larger the value, the better and better the high speed durability.

<Ride comfort performance>
Each test tire was assembled on a rim and mounted on a commercially available car, and the ride comfort was evaluated by a 10-step sensory evaluation by a driver. The higher the score, the better the ride comfort and the better.

<Rolling resistance>
The rolling resistance of each test tire was evaluated by directly measuring the resistance of each test tire in a drum test at a speed of 80 km / h. The results are shown as an index with the resistance of the conventional example taken as 100. The smaller the index value, the smaller the rolling resistance and the better.

  As shown in the above table, in the test tires of each example using a reinforcing layer reinforced with a polyamide cord composed of a dicarboxylic acid (A) having 7 or more carbon atoms and a diamine (B), a comparative example and Compared with the test tires of the conventional examples, it was confirmed that while improving the riding comfort performance while ensuring the high-speed durability of the tire, the rolling resistance can be further reduced. In addition, the belt reinforcing layers in the test tires of each example had a plant-derived material ratio of 50% by mass or more, and were excellent in terms of reducing the amount of petroleum resources used.

1 bead core, 2 carcass, 3a, 3b belt layer, 4 cap layer, 5 layer layer, 6 bead filler, 11 bead part, 12 tread part, 13 side wall part

Claims (4)

In a pneumatic tire having a reinforcing layer reinforced with an organic fiber cord,
The pneumatic tire characterized in that the organic fiber cord is made of polyamide composed of a dicarboxylic acid (A) having 7 to 11 carbon atoms and a diamine (B).   The pneumatic tire according to claim 1, wherein the dicarboxylic acid (A) is made of a non-fossil raw material.   The pneumatic tire according to claim 2, wherein the dicarboxylic acid (A) is terephthalic acid or sebacic acid made of a non-fossil raw material.   The pneumatic tire according to any one of claims 1 to 3, wherein the diamine (B) has 4 to 10 carbon atoms.

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