Pneumatic tire

Abstract

This invention relates to a pneumatic tire that, while maintaining travelling durability, can improve driveability and can realize weight reduction, particularly a pneumatic tire that has a high post cure inflation pressure and is best suited for a small truck in which the air pressure is high. In the pneumatic tire, twisted cords formed of a polyketone fiber represented by the following formula (a) and having a thermal shrinkage stress value at a dry heat temperature of 150 DEG C of not less than 0.19 cN / dtex are used in cords for carcass layer formation. -(CH2-CH2-CO)n-(R-CO-)m- formula (a) wherein the relationship between n and m are represented by formula (b), and R represents an alkylene group having 3 or more carbon atoms. 1.05 = (n + m) / n = 1.00 formula (b).

Description

technical field [0001] The present invention relates to pneumatic tires. More specifically, it relates to a pneumatic tire using polyketone fiber as a tire cord, particularly as a pneumatic tire for small trucks, which has excellent characteristics in terms of light weight, good steering stability, and the like. Background technique [0002] Conventionally, polyketone fibers have been expected to have high strength, high modulus of elasticity, and excellent fatigue resistance, processability, heat resistance, dimensional stability, and adhesion, etc., so they have been proposed for use in tire cords, etc. The proposals used in the field (Patent Documents 1 to 3, etc.). [0003] From the characteristics of polyketone fibers as described above, it is expected to realize a pneumatic tire which has the same or better driving durability than conventional pneumatic tires of the same type, and which can improve steering stability and reduce weight. However, in none of the previou...

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Problems solved by technology

However, the actual situation is that the use of coated rubber having specified physical properties is restricted in use, and especially as the above-mentioned pneumatic tires for small trucks, it has not yet been realized.

[0005] In addition, Patent Document 2 proposes a heavy-duty pneumatic radial tire in which organic fiber cords such as polyester, aramid, rayon, or polyketone of 5,500 to 17,000 dtex are used for the carcass of the heavy-duty pneumatic tire. Furthermore, the folded portion of the carcass is folded back along the outer surface in the radial direction of the bead core, but it cannot be said that the characteristics of polyketone are used, and the actual situation is that it is about a heavy-duty pneumatic tire, as the above-mentioned Pneumatic tires for small trucks, not yet implemented

[0006] In addition, Patent Document 3 proposes to use an organic material of 5,500 to 17,000 dtex in the carcass of a pneumatic tire for heavy loads and has an elongation of 5.0% or less per 1 dtex of the cord drawn from the tire. Fiber cords, such as polyester, rayon, polyketone and other organic fiber cords are used as the organic fibers to form heavy-duty pneumatic radial tires, but it cannot be said that the characteristics of polyketone are used. It is about pneumatic tires for heavy loads. As the above-mentioned pneumatic tires for small trucks, it has not yet been realized.

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