Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2001-08-09
2002-08-27
Edwards, N. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S395000, C057S208000, C057S206000, C057S245000, C057S246000, C206S392000
Reexamination Certificate
active
06440555
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a package of a false twist yarn composed of polyester type fibers, particularly to a package of a false twist yarn composed of polytrimethylene terephtahlate fibers, capable of retaining favorable winding package shape, low in unwinding tension and a variation thereof, and capable of providing a high-quality knit or woven fabric.
BACKGROUND ART
As polyester type fibers excellent in elastic recovery and suitably used as material for a stretch fabric, a false twist yarn of polyester type fibers has been proposed, for example, in Japanese Unexamined Patent Publication No. 9-78373, which polymer component is mainly composed of polytrimethylene terephthalate.
When this false twist yarn is wound onto a package under winding conditions usually adopted for taking up a false twist yarn of polyethylene terephthalate type polyester fibers or nylon fibers, however, yarn shrinkage occurs in the package during the winding operation as the amount of wound yarn increases, and the hardness of the package becomes too high, whereby the package may collapse a paper tube or a package diameter becomes larger at the both ends of the paper tube to result in a high-selvage package shape. This causes the generation of single filament breakage, a difference in crimp characteristics between inner and outer portions of the package, and a change with time of the crimp characteristics, resulting in quality deterioration in knit or woven fabrics.
It is possible to avoid the collapse of paper tube and the generation of high-selvage package shape by lowering the winding tension so that the package hardness and the winding density become lower. However, a false twist yarn of polytrimethylene terephthalate fibers has a remarkable tendency to generate a single-filament snarl (a looped part of the filament individually twisted to jut out from a yarn surface). This tendency is accelerated as the winding tension is lowered to result in a failure to unwind the false twist yarn from the package due to entanglement of the single-filament snarls. This phenomenon is particularly significant in a single-heater type false twist yarn.
As another method for preventing the paper tube from collapsing, a double paper tube may be used for carrying out a high hardness and high density winding. While this countermeasure is effective for solving the problem relating to the collapse of the paper tube, the high-selvage package shape of the false twist yarn of polytrimethylene terephthalate fibers is not avoidable. Further, the false twist yarn of polytrimethylene terephthalate fibers, particularly that of a single-heater type, is characterized in a larger residual torque than the false twist yarn of polyethylene terephthalate type polyester fibers. The residual torque becomes larger as the package is wound harder to result in the generation of snailing during unwinding, which lowers the knitting/weaving ability, exaggerates the bias deformation of knit/woven fabric, develops a surface undulation in the knit/woven fabric, or generates a hard crepe.
DISCLOSURE OF THE INVENTION
An object of the present invention is to solve the above-mentioned drawbacks and provide a package of a false twist yarn composed of polytrimethylene terephtahlate fibers, capable of retaining favorable winding package shape, smooth in unwinding operation and capable of providing a high-quality knit or woven fabric.
The present inventors have diligently studied a package of a false twist yarn composed of polytrimethylene terephtahlate fibers, and have found that the object is achievable by a yarn package having certain specifications, to complete the present invention.
That is, the present invention relates to a package of a false twist yarn composed of polytrimethylene terephthalate fibers, characterized in that the hardness and the winding density of the package and the number of crimps of the false twist yarn thus taken up simultaneously satisfy the following conditions (1), (2) and (3):
(1) 70≦hardness≦90
(2) 0.6 g/cm
3
≦winding density≦1.0 g/cm
3
(3) hardness×the number of crimps≧520
The present invention will be described in more detail below.
Polytrimethylene terephthalate fiber is a polyester fiber containing trimethylene terephthalate as a main repeated unit wherein the trimethylene terephthalate unit is contained at a ratio of approximately 50 mol % or more, preferably 70 mol % or more, more preferably 80 mol % or more, further more preferably 90 mol % or more. Accordingly, this fiber includes polytrimethylene terephthalate containing, as a third component, another acidic component and/or glycolic component of a total amount of less than approximately 50 mol %, preferably less than 30 mol %, more preferably less than 20 mol %, further more preferably less than 10 mol %.
The polytrimethylene terephthalate is synthesized by bonding terephthalic acid or functional derivative thereof with trimethylene glycol or functional derivative thereof in the presence of catalyst under a suitable reactive condition. In this synthesis process, one kind or more of third component may be added to be copolymerized polyester or, after individually preparing a polyester other than polytrimethylene terephthalate such as polyethylene terephthalate; nylon; and polytrimethylene terephthalate, they may be blended together or spun to be a composite fiber (a sheath-core type fiber or a side-by-side type fiber).
The third component to be added includes aliphatic dicarbonic acid (oxalic acid, adipic acid or the like), cycloaliphatic dicarbonic acid (cyclohexane dicarbonic acid or the like), aromatic dicarbonic acid (isophthalic acid, sodium sulfoisophthalic acid or the like), aliphatic glycol, (ethylene glycol, 1,2-propylene glycol, tetramethylene glycol, or the like), cycloaliphatic glycol (cyclohexane dimethanol or the like), aliphatic glycol containing aromatic group (1,4-bis(&bgr;-hydoxyethoxy) benzene or the like), polyether glycol (polyethylene glycol, polypropylene glycol or the like), aliphatic oxycarbonic acid (&ohgr;-oxycapronic acid or the like) or aromatic oxycarbonic acid (p-oxybenzoic acid or the like). Also, compounds having one or three or more ester-forming functional groups (benzoic acid, glycerin or the like) may be used provided the polymer is maintained substantially in a linear range.
The polytrimethylene terephthalate may be added with a delustering agent such as titanium dioxide, a stabilizing agent such as phosphoric acid, an ultraviolet absorbing agent such as a derivative of hydroxybenzophenone, a crystal neucleator, such as talc, a lubricant such as aerozil, an antioxidant such as a derivative of hindered phenol, a flame retardant, an antistatic agent, a pigment, a fluorescent whitener, an infrared absorbing agent, and an antifoaming agent.
The polytrimethylene terephthalate fiber used in the present invention may be spun by either a normal method wherein, after an undrawn yarn has been obtained at a takeup speed of approximately 1500 m/min, the yarn is drawn at a draw ratio in a range from approximately 2 to 3.5 times, a spin-draw method wherein a spinning process is directly combined with a drawing process, a spin-takeup method wherein a yarn spun from a spinning machine is directly taken up at a high speed of 5000 m/min or more.
The configuration of the fiber may be either uniform or irregular in thickness in the lengthwise direction, and a cross-sectional shape thereof may be circular, triangular, an L-shape, a T-shape, a Y-shape, a W-shape, an eight-lobe shape, a flat shape and a dog-bone shape. Also, the fiber may be hollow or even an indefinite shape.
The false twist may be imparted by any conventional false twisting method such as a pin type, a friction type, a nip belt type, an air-twisting type or others. Also, either a single-heater system or a double-heater system may be adopted. Further, the false twist yarn may be obtained by draw-texturing a pre-oriented yarn (POY).
A hardness of the yarn package must be 70 or more and 90 or less, preferably 75 or more and 90 or less. A
Akita Shoichi
Yuuki Yasunori
LandOfFree
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