Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Patent
1997-08-29
1999-04-06
Edwards, Newton
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
428395, D02G 300
Patent
active
058915672
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an industrial polyester filamentary yarn and a tire cord formed from this filamentary yarn. More particulary, it relates to a polyester filamentary yarn, a tire cord having an improved fatigue resistance due to increased thermal dimensional stability and strength, and low shrinkage as well as a process for production of this yarn.
2. Description of the Prior Art
In general, nylon, rayon, polyester etc. fibers are typical examples of the fibers which have been used as reinforcements in rubber tires. Nylon tire cord has higher strength and toughness than the other materials due to the inherent properties of nylon fiber and has been generally used in bias tires for trucks, buses etc. Rayon tire cord provides a low degree of shrinkage and has good thermal and dimensional stability due to the inherent properties of rayon fiber and has been generally used in high speed radial travelling tires for passenger cars.
However, nylon tire cord has poor dimensional stability due to its low modulus characteristics and high shrinkage and further exhibits flat spots due to its low glass transition temperature(T.sub.g). Rayon tire cord also has low modulus characteristics and exhibits a sharp decrease in strength after the fibers have been formed into a tire cord.
In view of these defects found in both nylon and rayon tire cords, polyester tire cord has been widely used.
Prior art polyester fibers that have been used in tires have benzene lings in their molecular structure, and a rigid molecular chain. Accordingly, tire cord formed from polyester yarn has good elastic modulus and good fatigue resistance, and provides few flat spots, excellent creep resistance and excellent endurance. For these reasons, polyester tire cord has been widely used in radial tires for passenger cars.
However, in spite of the above described merits, conventional polyester tire cords do have a problem; they undergo substantial variation in their properties with temperature due, it is thought, to hysteresis effect. In particular, conventional industrial high strength polyester fibers generally exhibit substantial shrinkage when heated.
Also, when industrial polyester fibers have been incorporated into a rubber matrix of a tire, as the tires rotate during use the fiber is stretched and relaxed during each tire rotation. Further, the internal tire air pressure stresses the fiber, and tire rotation while axially loaded or stressed causes repeated stress variations, particularly on unsmooth surface.
Since more energy is consumed during the stretching of a fiber than is recovered during its relaxation, the difference of energy dissipates as heat. This is termed hysteresis or work loss. Significant temperature increases have been observed in rotating tires during use which are attributable at least in part to this fiber hysteresis effect.
The variation in properties caused by heat generation occurs due to moisture and amines contained in conventional rubber solutions used in rubber treatments for producing tire cord, and the observed variation tends to be increased when the content of carboxyl end group is high, leading to a significant lowering of strength and fatigue resistance.
In recent years, as radial tires having high performance have been widely developed and used, the demand for polyester tire cord with superior properties, especially properties superior to those obtained with nylon or rayon tire cord, has been increasing. Therefore, research into development of a polyester tire cord having improved fatigue resistance by minimizing the heat generated due to the hysteresis effect has been undertaken.
Prior art methods for improving fatigue resistance of polyester fibers have focused on a chemical method for increasing stability by reducing the content of carboxyl groups in the polyester and a method wherein highly-oriented undrawn yarn produced using a polyester with a relatively low intrinsic viscosity(IV), or produced by employing a high-speed spinning proces
REFERENCES:
patent: 4101525 (1978-07-01), Davis et al.
patent: 4134884 (1979-01-01), Frankfort et al.
patent: 4195052 (1980-03-01), Davis et al.
patent: 4491657 (1985-01-01), Saito et al.
patent: 5288553 (1994-02-01), Collins et al.
patent: 5472781 (1995-12-01), Kim et al.
patent: 5558935 (1996-09-01), Tanaka et al.
patent: 5658665 (1997-08-01), Kim et al.
Choi Duk-Yong
Kim Gi-Woong
Kim Sung-Joong
Lee Sang-Min
Edwards Newton
Kolon Industries Inc.
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