Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2001-06-26
2003-01-07
Edwards, N. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S395000
Reexamination Certificate
active
06503623
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a yarn composed of polytrimethylene terephthalate fibers, particularly to a yarn composed of polytrimethylene terephthalate multifilamentary fibers having a single-fiber size in a range from 1 to 56 dtex, which are collected together to have a total size in a range from 2000 to 22000 dtex and a racket string, and a musical instrumental string, formed of such a yarn.
BACKGROUND ART
Polytrimethylene terephthalate fiber is an epoch-making fiber having merits similar to those of nylon fiber, such as a soft touch derived from a low elastic modulus (modulus of elasticity) thereof and a superior elastic recovery (modulus of elastic recovery), as well as merits similar to those of polyethylene terephthalate fiber, such as a wash-and-wear property, a dimensional stability and a resistance to yellowing. However, since trimethylene glycol, which is one of the raw materials of polytrimethylene terephthalate fiber, was expensive, this fiber has hardly been commercially produced up to now. A technology for industrially producing trimethylene glycol at a low cost has been developed, and now the commercialization of the polytrimethlene terephthalate fiber has been proceeded in the clothing and carpet fields in which the above-mentioned properties are suitably usable.
However, the polytrimethylene terephthalate fiber has hardly been applied to fields other than clothing until now.
Also, there is no case wherein the polytrimethylene terephthalate multifilamentary fibers are collected together to form a yarn and used without being woven or knit into a fabric, or applied as commercial products to a field other than the clothing. Therefore, there is no yarn consisting of polytrimethylene terephthalate multifilamentary fibers having a single-fiber size in a range from 1 to 56 dtex, which are collected together to form a unitary yarn having a total size in a range from 2000 to 22000 dtex.
In the prior art, polytrimethylene terephthalate multifilamentary fibers having a single-fiber size in a range from 0.00011 to 11 dtex, which are collected to form a yarn having a total size in a range from 5.6 to 1100 dtex, are known as disclosed in WO99/11845 filed by the applicant of the present application. However, the fibers disclosed in this publication are used for forming a fabric article after being woven or knit, and there is no description in that polytrimethylene terephthalate fibers having a single-fiber size in a range from 1 to 56 dtex are collected together to form a unitary yarn having a total size in a range from 2000 to 22000 dtex, which yarn is used, as it is or after the fibers are adhered together or coated with resin, for a racket string or a musical instrumental string.
A multifilamentary yarn according to the present invention is high in strength, elastic recovery and stress-retaining ratio and excellent in water resistance, softness and yarn-homogeneity in comparison with the prior art yarn formed by collecting filamentary fibers having a single-fiber size exceeding 56 dtex to have a total size in a range from 2000 to 22000 dtex, and is suitably used in a field wherein the yarn is used as it is or after the fibers are adhered together and/or coated with resin, particularly for a racket string or a music instrumental string.
There are two types of string for tennis or badminton rackets in the prior art; one being prepared from synthetic fibers, for example, of nylon or others and the other being prepared from a natural source such as the gut of cattle or sheep, or an animal tendon of, for example, a whale; which are suitably twisted and coated with resin. Although it is said that such a natural origin string is favorable in resilience, ball-control, impact feeling and ball-holding feeling because it still has a suitable elongation even though it has stretchingly been set across a frame under a high tension, the string of a natural origin is problematic in durability and resistance to water as well as its expensiveness.
Contrary to this, the synthetic string is excellent in durability and resistance to water, but if it is used for a long period in a tensed state which is favorable for obtaining good resilience, the string is liable to gradually extend, which causes a tension loss, lowers the resilience and deteriorates the impact feeling and the ball-holding feeling. As a result, the re-setting of the string is often required even before the string is broken. The string of nylon fibers has a high standard regain and tends to easily elongate in a wet state, whereby if the string gets wet, the string tension largely lowers to deteriorate the impact resilience, impact feeling and ball-holding feeling. Since a string of high elastic modulus fibers such as aramid fibers has a high strength and a low elongation at break, it changes less in tension with time even though the string has been stretchingly set across a frame at a high tension, but is problematic in that the resilience is too low to absorb the impact because the string is not stretchable upon ball impact.
There is a description in Japanese Unexamined Patent Publication No. 5-262862 that a 657 denier size polytrimethylene terephthalate monofilamentary fiber is very suitably used as a racket string because of its lower Young's modulus and larger elongation at break in comparison with those of nylon fiber. Also there is another description therein that the multiple lengths of polytrimethylene terephthalate monofilament will be bonded together using a polymer coating to form a unitary yarn used as a racket string. Neither physical properties nor performances of the actual string, however, are disclosed therein. Also, there is no description of a total size of the collected multifilamentary fibers and the string. The disclosed monofilamentary fiber is as fine as 657 deniers, which has a suitable resilience at an initial stage when a plurality thereof are collected together and used as a racket string, but has a drawback in that the resilience falls with time. Further, the impact feeling, the ball-controllability and the impact resistance are poor.
Under the circumstances, there has been a demand for a high-durability racket string capable of being set across a racket frame under a high tension and having a favorable resilience lasting for a long time as well as being excellent in impact resistance and ball-controllability.
Regarding a string for a musical instrument, a metallic string, a nylon string and a natural origin string are mainly used in the prior art. The nylon string is liable to slacken with time after it has stretchingly been set on the instrument body and tuned and thus needs frequent tuning and therefore a considerable time is required to put in tuning. Also, the nylon string is not always satisfactory because it is often slackened or tensed to vary in tuning in accordance with the environmental humidity due to the hygroscopic property thereof. On the other hand, the natural source string has stability in tuning over time under a low humidity in comparison with the nylon string, but has a problem in that it lacks uniformity in size of yarn because of its natural source which may cause the breakage of the string due to the concentration of stress to a limited part. Also, the natural source string is expensive.
Under the circumstances, there has been a demand for a musical instrumental string excellent in tunability and in stability in tuning over time and with a change in humidity.
Although Japanese Unexamined Patent Publication No. 5-262862 discloses that a polytrimethylene terephthalate monofilamentary yarn is used as a yarn for a guitar, it does not indicate a concrete method for manufacturing the same or the effects thereof.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a yarn composed of polytrimethylene terephthalate fibers, particularly polytrimethylene terephthalate multifilamentary fibers having a single-fiber size in a range from 1 to 56 dtex, which are collected together to have a total size in a range from 2000 to 22000 dtex. This
Oue Kazuto
Yamazaki Hiroshi
Asahi Kasei Kabushiki Kaisha
Edwards N.
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
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