Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2003-04-04
2004-11-09
Edwards, N. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S359000, C428S395000
Reexamination Certificate
active
06815060
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a spun yarn comprising poly(trimethylene terephthalate) staple fibers.
BACKGROUND ART
Spun yarns produced from natural fibers such as cotton, wool and linen (ramie) as raw materials have excellent feelings peculiar to the respective fibers, so that they find wide applications. However, spun yarns produced totally from such natural fibers have drawbacks in handling characteristics and in durability when worn, such as relatively low strength, large shrinkage after washing and large configurational change.
Therefore, in order to cope with such drawbacks, wide use is made of blended spun yarns produced by blend spinning (mix spinning) natural fibers and staples (discontinuous fibers or short fibers) of synthetic fibers. A representative example of the synthetic fibers used in the blend spinning is a poly(ethylene terephthalate) fiber. The blend spinning thereof exerts apparent effects on improvements in strength and in shape stability. However, the poly(ethylene terephthalate) fiber has large Young's modulus, so that its feel is hard. Thus, the poly(ethylene terephthalate) fiber has a fatal drawback in that when blend-spun with natural fibers, the excellent feel of natural fibers would inevitably be deteriorated even if the blending ratio thereof is low.
Recently, appropriate stretchability and stretch-back property are increasingly demanded on woven fabrics and knit fabrics for clothing. CSY (core spun yarn) having a core constituted of an elastic yarn, such as spandex, is well known as a spun yarn with stretchability and stretch-back property. However, spandex poses such a problem that embrittlement by chemicals, such as chlorine, is serious and colorfastness thereof is low. Further, CSY has drawbacks in that breakage of spandex constituting a core yarn (namely, core breakage) is likely to occur during the manufacturing or aftertreatment, and that accurate insertion of spandex in the core is technically difficult. Yarn having spandex protruding outside inflicts a loss in manufacturing, thereby lowering the yield and increasing the manufacturing cost. Because of these problems, there is a demand on a spun yarn with excellent stretchability produced without the use of spandex.
On the other hand, poly(trimethylene terephthalate) fibers are publicly known as fibers of low initial stretching resistance (Young's modulus) and high elastic recovery. Japanese Patent Publication No. 49(1974)-21256 discloses a crimped fiber with a flexure recovery of at least 70% wherein a poly(butylene terephthalate) fiber and a poly(trimethylene terephthalate) fiber are contained in a proportion of 50 wt % or more, and further discloses a staple fiber obtained by cutting the crimped fiber into given lengths. Japanese Patent Laid-Open No. 11(1999)-189938 discloses a staple fiber of poly(trimethylene terephthalate) having its elastic recovery percentage of elongation and flexure recovery enhanced by thermal treatment.
In both of these published inventions, there is no particular disclosure at all with respect to the most suitable spun yarn specifications and characteristics regarding the spun yarn produced from the above staple fibers, although the elastic recovery percentage of elongation and flexure recovery of poly(trimethylene terephthalate) filament and staple fibers are disclosed.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide a poly(trimethylene terephthalate) spun yarn which is excellent in knitting and weaving characteristics and excellent in at least one of stretchability, stretch-back property, shape stability and durability when worn for a prolonged period of time, etc., and by which a woven fabric and knit fabric making the most of the feeling of other material blended with poly(trimethylene terephthalate) staple fibers can be obtained.
The inventors have made extensive and intensive investigations with a view toward attaining the above object. As a result, it has been found that the above object can be attained by the use of a spun yarn with specified properties comprising poly(trimethylene terephthalate) staple fibers. The present invention has been completed on the basis of this finding.
That is, the present invention is as follows.
1. A spun yarn comprising poly(trimethylene terephthalate) staple fibers (discontinuous fibers or short fibers) at a content of at least 15% by weight, the spun yarn having an elastic recovery percentage of elongation at 5% elongation satisfying the formula:
elastic recovery percentage of elongation at 5% elongation (%)≧0.1X+70 (a)
wherein X represents the content of poly(trimethylene terephthalate) staple fibers in the spun yarn (% by weight).
2. The spun yarn according to item 1 above, which is a composite spun yarn comprising poly(trimethylene terephthalate) staple fibers and other fibers, wherein the content of poly(trimethylene terephthalate) staple fibers is in the range of 15 to 70% by weight.
3. The spun yarn according to item 1 or 2 above, which exhibits an elongation at break (rupture) of 10% or greater.
4. The spun yarn according to item 1, 2 or 3 above, which exhibits a tenacity (tensile strength) and elongation product of 15 cN·%/dtex or greater.
5. The spun yarn according to any of items 1 to 4 above, which exhibits an I-coefficient or L-coefficient of 1.0 to 2.5.
6. The spun yarn according to any of items 1 to 5 above, to which a finishing oil has been applied, the finishing oil containing an alkyl phosphate salt whose alkyl group has 8 to 18 carbon atoms on the average.
In the present invention, the elastic recovery percentage of elongation at 5% elongation (%), elongation at break (%), tenacity and elongation product (cN.%/dtex), initial stretching resistance (cN/dtex), I-coefficient and L-coefficient were measured in the following manner.
(1) Elastic Recovery Percentage of Elongation at 5% Elongation
Initial load specified in JIS-L-1095 (method of testing a common spun yarn) was applied to each spun yarn, and the length thereof was extended to given elongation L (5%=1 cm) with the use of constant-rate extension type tensile tester in accordance with the method of measuring an elastic recovery percentage of elongation (method A) under such conditions that the chuck spacing was 20 cm and that the stretch speed was 50% of the chuck spacing per minute. The spun yarn was allowed to stand still for 1 min, and the original length thereof was restored at the same speed. The spun yarn was allowed to stand still for 3 min, and again the length thereof was extended to point L
1
at which the initial load was applied at the same speed. The elastic recovery percentage of elongation Ec (%) was calculated by the formula:
Ec
(%)={(
L−L
1
)/
L
}×100
The test was performed 5 times, and the measurements were averaged.
(2) Elongation at Break, Tenacity and Elongation Product and Initial Stretching Resistance
Initial load specified in JIS-L-1095 (method of testing a common spun yarn) was applied to each spun yarn, and a tensile test thereof was performed with the use of constant-rate extension type tensile tester under such conditions that the chuck spacing was 30 cm and that the stretch speed was 100% of the chuck spacing per minute. Thus, the tenacity at break (cN/dtex) and elongation at break (%) (ratio of extent of elongation at break to chuck spacing) were determined.
the tenacity and elongation product was calculated by the formula:
Tenacity and elongation product (cN·%/dtex)=tenacity at break (cN/dtex)×elongation at break (%)
The initial stretching resistance (cN/dtex) was determined by, on a drawn load—elongation curve, identifying a point of maximum load change vs. elongation change at a proximity to the original point and by measuring the gradient of a tangential line at the identified point.
The test was performed 20 times, and the measurements were averaged.
(3) I-Coefficient and L-Coefficient
The I-coefficient and L-coefficient are coefficients expressing the uniformity of yarn, and are also re
Asahi Kasei Kabushiki Kaisha
Edwards N.
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