JP2004244763A - Elastic filament bundle for cut fiber and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastic filament bundle for cut fiber, capable of suppressing the occurrence of the error of cutting or the unevenness of the cutting when forming the elastic filament bundle into the cut fiber; and to provide a method for producing the elastic filament bundle. <P>SOLUTION: (1) The elastic filament bundle for the cut fiber comprises elastic filaments having ≥200% elongation at break, and has ≤30% average residual shrinkage, and ≤30% average value of the dispersion of the residual shrinkage. (2) The method for producing the elastic filament bundle for the cut fiber comprises forming a beam by winding the many elastic filaments in a tensed state into a sheet shape, relaxing the sheet-shaped elastic filaments taken out from the two or more beams to regulate the residual shrinkage of the elastic filaments so as to be ≤30%, and winding the resultant filaments as the filament bundle. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an elastic long fiber bundle for cut fiber (tow), and more particularly to an elastic long fiber bundle for cut fiber capable of obtaining uniform elastic short fibers without cut errors and spots, and a method for producing the same. .
[0002]
[Prior art]
Conventionally, in the production of staple fiber used as a raw material for spinning or the like, a fiber bundle (tow) is formed by using a recycled fiber, a semi-synthetic fiber, a synthetic fiber, or the like having a breaking elongation of 100% or less. A method of winding a tow into a cylinder and continuously cutting the tow to obtain a desired fiber length is employed (for example, see Patent Document 1).
However, when a conventional cutting device is used for cutting an elastic long fiber bundle (tow) having a high elongation at break, there is a problem that a cut error is likely to occur, and a staple fiber that can be used cannot be obtained due to cut spots. Was. Therefore, there has been a demand for the development of an elastic long fiber bundle (tow) capable of forming a uniform cut fiber from an elastic long fiber bundle (tow) having a breaking elongation of 200% or more, and a method of uniformly cutting the same.
[0003]
[Patent Document 1]
JP-B-51-6772 [0004]
[Problems to be solved by the invention]
An object of the present invention is to provide an elastic long fiber bundle for cut fibers and a method for producing the same, which can solve the problems of the above technology and can suppress the occurrence of cut errors and spots when the elastic long fiber bundle is used as cut fibers. To provide.
[0005]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above problems, and as a result, elastic long fibers having a high elongation at break, when formed into an elastic long fiber bundle due to a high residual shrinkage or at the time of cutting thereof, the expansion and contraction of the fibers. By this, the residual shrinkage ratio becomes uneven, and cut errors and cut spots are likely to occur.However, the residual shrinkage of the elastic filament is relaxed, the residual shrinkage ratio is set to a predetermined value or less, and the variation is within a predetermined range. By doing so, they have found that uniform elastic short fibers without cut errors and cut spots can be obtained, and have reached the present invention.
That is, the invention claimed in the present application is as follows.
[0006]
(1) A cut fiber comprising an elastic fiber having a breaking elongation of 200% or more, an average residual shrinkage of 30% or less, and a variation of the residual shrinkage of 30% or less of an average value. Elastic long fiber bundle.
(2) The elastic long fiber bundle for cut fibers according to (1), wherein the single fiber fineness of the elastic fiber is 2 to 20 dtex.
(3) A plurality of elastic long fibers are wound into a sheet in a tension state to form a beam, and the sheet-like elastic long fibers are drawn out of the plurality of beams to relax and relax, and the residual shrinkage of the elastic long fibers A method for producing an elastic long fiber bundle for cut fibers, comprising reducing the ratio to 30% or less, and winding these into a fiber bundle.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Elastic fibers having a breaking elongation of 200% or more, preferably 300% or more are used for the elastic long fiber bundle for cut fibers of the present invention. If the elongation at break of the elastic fiber is less than 200%, sufficient extensibility cannot be obtained when a spun yarn mixed with an elastic short fiber is obtained.
Further, the elastic long fiber bundle for cut fibers has an average residual shrinkage of 30% or less, preferably 20% or less, and a variation in the residual shrinkage of 30% or less of the average value, preferably 20%. It is necessary.
[0008]
Elastic long fibers are generally supplied in a state of being wound around a paper tube, but the elastic long fibers wound around a paper tube usually have a residual shrinkage of -1% to 20%, and can be unwound or wound. The repetition may cause the residual shrinkage to further vary. Therefore, when unwinding and collecting the elastic filaments wound around the paper tube to form an elastic filament bundle having a desired thickness, how to make the residual shrinkage ratio uniform is determined by the uniform elastic shortness. This is an important point in producing fibers. In addition, in order to reduce the variation in the residual shrinkage, it is generally considered that an elastic fiber having a small residual shrinkage should be used.However, when the elastic long fiber is unwound and wound, it may be under a certain degree of tension. If the operation is not performed, the elastic filaments tend to stick to each other to cause a collective yarn breakage or extreme elongation unevenness. Therefore, uniform elastic short fibers cannot be obtained simply by using an elastic fiber having a small residual shrinkage.
[0009]
In the present invention, the relaxation treatment is performed so that the residual shrinkage of the elastic long fiber bundle is 30% or less, and the variation of the residual shrinkage is adjusted to be 30% or less of the average value. Even if the cutting device is used for cutting, the occurrence of cut errors and cut spots can be suppressed, and uniform elastic short fibers can be obtained.
Here, the residual shrinkage ratio refers to a value calculated from the following formula from the fineness (D ₀ ) wound around a paper tube or a beam and the fineness (D ₁ ) when freed, as described later.
Residual shrinkage (%) = [(D ₁ −D ₀ ) / D ₀ ] × 100
The variation in the residual shrinkage was determined by extracting ten fibers from the obtained elastic filament bundle, measuring the residual shrinkage of each fiber, and repeating this three times in the longitudinal direction of the bundle. Means a value represented by a ratio of a difference between the average value and the average value to the average value.
[0010]
The elastic fiber used in the present invention includes, for example, a chain extender having a polyfunctional active hydrogen atom in an isocyanate-terminated prepolymer prepared with an organic diisocyanate and a substantially linear polymer diol, and Elastic fibers obtained by dry spinning, wet spinning or melt spinning an elastic high molecular polymer having a urethane group in the molecule obtained by reacting a terminal blocking agent having a monofunctional active hydrogen atom.
The elastic polymer described above may optionally contain an organic or inorganic compounding agent having a specific chemical structure used in a known polyurethane polymer composition, for example, a benzophenone-based compound, a benzotriazole-based compound, a hindered amine-based compound. UV absorbers such as compounds, antioxidants such as hindered phenol compounds, inorganic fine particles such as zinc oxide, titanium oxide, hydrosalcite, etc., magnesium stearate, calcium stearate, polytetrafluoroethylene, organopolysiloxane, etc. May be appropriately compounded.
[0011]
When producing the elastic fiber by spinning the above elastic high molecular polymer, the single fiber of the elastic fiber is made to exist alone without adhering to each other, and is spun with almost no spinning oil agent to form the short fiber. It is preferable to apply an oil agent after the cut in order for smoothness and antistatic property required for spinning. By applying the oil agent, carding at the time of spinning can be made smooth, and poor opening of the spinning process and the like, draft spots, and the like can be avoided.
The single fiber fineness of the elastic fiber used for the elastic long fiber bundle is preferably 2 to 20 dtex. This single yarn fineness is calculated from the fineness when left free. The fineness of the single yarn may be selected appropriately according to the other fibers to be mixed, but it can correspond to many general fibers within the above range.
[0012]
The elastic long fiber bundle for a cut fiber of the present invention is formed by winding a plurality of elastic long fibers into a sheet in a tension state to produce a beam, and extracting the sheet-like elastic long fibers from the plurality of beams to relax and relax. After setting the residual shrinkage to 30% or less, it can be obtained by winding as an elastic long fiber bundle.
FIG. 1 is an explanatory diagram of a manufacturing process of a winding beam used in the present invention, and FIG. 2 is an explanatory diagram of a manufacturing process of an elastic long fiber bundle for cut fibers of the present invention.
In FIG. 1, a plurality of (usually 300 to 1500) elastic long-fiber cheeses (paper tubes 1a) are set on a warping creel provided with a device capable of rolling and unwinding a winding surface of a paper tube 1a on a rotating drum 1. The elastic long fiber wound around each of the paper tubes 1 a is unwound through the rotary drum 1 and sent out in a sheet form to be sent out to the roll 2.
[0013]
When the elastic long fiber wound around the paper tube 1a is wound in a sheet state into the winding beam 4 in a tensioned state, it is preferable that the winding surface of the paper tube 1a be rolled into contact with the rotating drum 1 and unwound. Thereby, it is possible to make the winding layer of the paper tube 1a stick or turbulent, and to equalize the unwinding tension of the outer and inner layers. In the case of unwinding, the residual shrinkage difference may be increased by inducing the tension or turbulence of the winding layer and the tension fluctuation due to the difference in tension between the outer and inner layers.
A winding machine having a winding beam 4 and a rotating drum 4a is provided in front of the warping creel, and the sheet-like elastic long fiber that has passed through the delivery roll 2 and the stretching roll 3 contacts the rotating drum 4a. The sheet is wound in a tension state on the rotating take-up beam 4 into a sheet of uniform density.
The draft rate at this time is calculated by the following equation.
Pre-draft rate = [(AB) / A] × 100
Beam draft rate = [(CA) / A] × 100
A is the yarn speed of the delivery roll, B is the yarn speed of the rotary drum, and C is the yarn speed of the winding beam.
[0014]
When unwinding the elastic filaments and winding them up on the take-up beam 4, if the work is not performed under a certain amount of tension, the elastic filaments will stick to each other to cause collective yarn breakage and extreme elongation spots. The pre-draft rate is preferably 80 to 150%, more preferably 90 to 130%, and the beam draft rate is preferably 40 to 150%, more preferably 50 to 120%.
The fineness of the fiber bundle of the obtained take-up beam 4 is as thin as about 30,000 dtex, and the residual shrinkage is as large as 50% or more. Therefore, as shown in FIG. Is drawn out by a draw-out roll 5 and guided to a relaxation relaxation box 9, subjected to relaxation relaxation treatment to reduce the residual shrinkage to 30% or less, and then sent out through a delivery roll 7 and a combination roll 7 to a total fineness of 100,000. A desired elastic long fiber bundle (tow) of decitex or more is formed.
[0015]
Regarding the total fineness of the elastic long fiber bundle, an arbitrary elastic long fiber bundle can be obtained by increasing or decreasing the number of creeled paper tubes or the number of beams. By setting the total fineness of the elastic long fiber bundle to 100,000 decitex or more, the working efficiency in the subsequent industrial production can be improved.
In order to reduce the residual shrinkage of the elastic long fiber bundle to 30% or less, the relaxation zone where the sheet-like elastic long fiber drawn out from the winding beam 4 is left under no tension or under a low tension of 0.02 cN / decitex or less. Can be relaxed and relaxed by its own residual shrinkage rate, but the dry relaxation heat treatment is performed at 70 ° C. to 140 ° C. in the relaxation relaxation box 9 to promote relaxation and relaxation. It is preferable to feed the tow take-up beam 8 by sending it out with the sending roll 6 at a low speed and carefully aligning it with the tow take-up beam 8 in order to obtain an elastic long fiber bundle having a residual shrinkage of 30% or less and a small variation. In particular, in winter, the room temperature falls, and relaxation of residual shrinkage is easily suppressed, so that dry heat treatment is preferably used together.
[0016]
The obtained elastic long fiber bundle (tow) is supplied directly to a cutting machine in a state where the residual shrinkage ratio is 30% or less, or is carefully wound up on a fiber bundle winding beam 8 and then supplied to the cutting machine for cutting. Is done. The method for cutting into short fibers is not particularly limited, and for example, a known method such as cutting with a knife blade, heat, high frequency, or the like can be used.
[0017]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In addition, the measurement in an example was performed by the following method.
(1) Single yarn fineness: It was calculated by the formula (A) / (B) from the fineness (A) and the number of filaments (B) when left free.
(2) Residual shrinkage: Calculated by the following formula from the fineness (D ₁ ) when free from the fineness (D ₀ ) wound around a paper tube or a beam.
Residual shrinkage (%) = [(D ₁ −D ₀ ) / D ₀ ] × 100
The fineness D ₀ is a fiber of a certain length immediately after unwinding from a paper tube or a beam, and the fineness D ₁ is a fiber of a certain length after being released, and the mass is measured. It means a value converted to the mass of fiber per 10,000 m.
(3) Pre-draft ratio and beam draft ratio: The pre-draft ratio and the beam draft ratio were determined from the yarn speed (A) of the rotary drum of the creel (B) and the yarn speed (B) of the roll and the yarn speed (C) of the take-up beam according to the following equations.
Pre-draft rate (%) = [(BA)] / A × 100
Beam draft rate (%) = [(CA)] / A × 100
[0018]
Example 1
Using a polyurethane solution having a polymer concentration of 34% by weight using dimethylacetamide as a solvent, the single fiber exists alone without adhesion, and is dry-spun without applying an oil agent to obtain 44 decitex / 4 filaments and a single yarn. A fineness of 11.55 dtex, a breaking elongation of 610%, a fineness of 40.2 dtex wound on a paper tube, a free fineness of 46.2 dtex and a residual shrinkage of 14.9%, a 500 gm rolled paper tube (total yarn length) (112,500 m).
[0019]
700 rolls of this elastic filament 500 gm rolled paper tube are set on a warping creel equipped with a rotary drum unwinding device of a warping machine manufactured by KARL MAYER Co., Ltd. Tension running is performed at a pre-draft rate of 110% at a yarn speed of 273 m / min. Next, at a yarn speed of 234 m / min, the winding beam 4 is slightly relaxed and wound around the winding beam 4 at a speed at which the beam draft rate becomes 80%. At the time of winding, one elastic long fiber is drawn into one reed (reed density: 13 / cm) in front of the beam to form a sheet of 30,800 decitex, and wound in a 53.3 cm wide beam under tension. The residual shrinkage was 80 ± 3%, and the film could be wound with high working efficiency.
[0020]
Next, four take-up beams 4 are arranged, and an elastic long fiber sheet is drawn out from each beam at a low speed of 16 m / min. After the residual shrinkage is alleviated between the feed roll 6 and the feed roll 6, the roll is carefully matched at a yarn speed of 1 m / min with the aligning roll 7 to form a 123,200 decitex sheet-like elastic long fiber bundle having a width of 53.3 cm. It was wound on the tow take-up beam 8. The residual elastic shrinkage of the elastic filament bundle was 5 ± 1%, and a uniform elastic filament bundle was obtained.
This elastic long fiber bundle was cut into a fiber length of 38 mm using a knife blade cutter, and the obtained elastic short fibers were cut fibers having a length of 38 ± 1 mm and excellent uniformity.
[0021]
Example 2
In the first embodiment, after the elastic long fiber sheet is drawn from the winding beam 4 at a low speed of 16 m / min with the draw roll 5, the residual roll ratio is relaxed by the relaxation relaxation box 9 with dry heat of 70 ° C. to send out the roll. 6 at 5.5 m / min, carefully aligning with the aligning roll 6 and then winding up the tow take-up beam 8 at 6.0 m / min to produce elastic short fibers in the same manner as in Example 1. .
The residual shrinkage of this elastic long fiber bundle was 29 ± 2%, and the short fiber length after cutting 38 mm was 38 ± 2 mm, which was a cut fiber excellent in uniformity.
[0022]
Comparative Example 1
In Example 1, four take-up beams 4 having a sheet width of 53.3 cm are arranged, and an elastic long fiber sheet is drawn out from each take-up beam 4 by a draw-out roll 5 at a low speed of 16 m / min. Was carefully adjusted at a yarn speed of 10 m / min with the sending roll 6 and the combining roll 7 without using the sheet, and wound up on the tow take-up beam 8 as a 123,200 decitex sheet-like elastic long fiber bundle having a width of 53.3 cm. Except for the above, elastic short fibers were produced in the same manner as in Example 1.
The residual shrinkage rate of this elastic long fiber bundle was non-uniform, that is, 50 ± 15%. The elastic long fiber bundle was a very uneven elastic long fiber bundle in which the contracted portion and the elongated portion were mixed and the fiber bundle was wavy.
This elastic long fiber bundle was cut by a knife blade cutting machine, but was not uniformly gripped by the feed roll portion of the cutting machine, and as a result of expansion and contraction, short fibers cut to a 38 mm fiber length had cut errors. The resulting non-uniform cut fiber was 38 ± 4 mm in length.
[0023]
【The invention's effect】
According to the elastic long fiber bundle for cut fibers of the present invention and the method for producing the same, even when an elastic long fiber having a high elongation at break is used, the residual shrinkage does not become uneven due to expansion and contraction of the fiber, and cut errors and cuts are prevented. Uniform elastic short fibers without spots can be obtained.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a manufacturing process of a winding beam used in the present invention.
FIG. 2 is an explanatory view of a production process of an elastic long fiber bundle for cut fibers of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Rotary drum, 1a ... Paper tube, 2 ... Delivery roll, 3 ... Stretch roll, 4 ... Take-up beam, 4a ... Rotary drum, 5 ... Extraction roll, 6 ... Delivery roll, 7 ... Lamination roll, 8 ... Tow take-up beam, 9 ... Relax relaxation box.

Claims (3)

An elastic long fiber bundle for cut fibers, comprising an elastic fiber having a breaking elongation of 200% or more, having an average residual shrinkage of 30% or less, and having a variation in the residual shrinkage of 30% or less of an average value. . The elastic long fiber bundle for cut fibers according to claim 1, wherein the single fiber fineness of the elastic fiber is 2 to 20 decitex. A plurality of elastic long fibers are wound into a sheet in a tensioned state to form a beam, a sheet-like elastic long fiber is drawn out from the plurality of beams to relax and relax, and the residual shrinkage of the elastic long fiber is reduced by 30%. % Or less, and then these are formed into a fiber bundle and wound up.

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