Rubber composition and pneumatic tire

Abstract

The present invention provides a rubber composition which makes it possible to improve the handling stability, ride comfort, and elongation at break in a balanced manner and at the same time to achieve satisfactory processability and fuel economy; and also provides a pneumatic tire formed from the rubber composition. The present invention relates to a rubber composition including a masterbatch that includes: a modified natural rubber with a phosphorus content of 200 ppm or less; and microfibrillated plant fibers. The rubber composition preferably has a ratio (E*a / E*b) of a complex modulus E*a in an extrusion direction to a complex modulus E*b in a perpendicular direction to the extrusion direction, both measured at a temperature of 70 DEG C and a dynamic strain amplitude of 2% under an initial elongation of 10%, of 1.05 to 6 .00, wherein the complex modulus E*a is 7 to 100 MPa.

Description

technical field [0001] The present invention relates to a rubber composition and a pneumatic tire manufactured using the rubber composition. Background technique [0002] Microfibrillated plant fibers such as cellulose fibers are mixed into the rubber composition as fillers, which can reinforce the rubber composition and increase the modulus (complex elastic modulus). However, since microfibrillated plant fibers have a strong self-cohesion force, their compatibility with rubber components is also poor, and their dispersibility at the time of rubber kneading is low. Therefore, even if it is blended, there may be a phenomenon that the fracture property or the fuel efficiency deteriorates, and a method for improving the dispersibility of the microfibrillated plant fibers is required. [0003] Patent Document 1 discloses a method of chemically modifying microfibrillated plant fibers to improve compatibility between rubber components and microfibrillated plant fibers. However, ...

AI Technical Summary

Problems solved by technology

[0006] As a method of increasing the modulus of the rubber composition, a method of increasing the amount of sulfur or a method of mixing butadiene rubber containing syndiotactic crystals is known. However, when these methods are used, the elongation at break may decrease and sufficient durability cannot be ensured. sex

In addition, rubber compositions used in tires are required to be excellent in ride comfort, but generally, the modulus of the rubber composition increases and the ride comfort tends to decrease.

As such, handling stability has a contradictory relationship with elongation at break and ride comfort, and it has been difficult to improve these properties in a balanced manner with conventional methods

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