JP4063684B2 - Method for producing flat synthetic fiber - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a synthetic fiber, and more specifically, a synthetic fiber spun from a nozzle having a flat hole in a synthetic fiber production process by a wet spinning method or a semi-dry semi-wet spinning method. It is related with the method of adjusting the flatness of this without nozzle replacement.
[0002]
[Prior art]
In the production of synthetic fibers, fibers produced by wet spinning method or semi-dry semi-wet spinning method are synthesized with various flatness ratios by spinning using a nozzle corresponding to the flatness ratio of the final product. Fibers are produced (Patent Documents 1 and 2). For this reason, when changing the flatness of the final product, it is necessary to replace the nozzle, which is not only very troublesome, but also causes a loss of stock solution and a decrease in productivity. As an improvement measure for this problem, it is possible to slightly adjust the flatness ratio by adjusting the spinning draft and the draw ratio, but it can only change the flatness ratio of the nozzle used up to about 40%. Also, it is difficult to finely adjust the fineness, and the actual situation is that it cannot be carried out.
[0003]
[Patent Document 1]
JP-A-61-102410
[0004]
[Patent Document 2]
JP-A-11-222716
[0005]
[Problems to be solved by the invention]
An object of the present invention is to efficiently perform product type switching in view of the problem of product type switching loss in the conventional synthetic fiber manufacturing process as described above.
[0006]
[Means for Solving the Problems]
As a result of intensive research to achieve the above-mentioned object, the inventors have made the flatness rate by reducing the temperature of the synthetic fiber to a temperature not less than 5 ° C. below the softening point of the resin and not higher than the melting point, and performing compression. The present inventors have found that it is possible to adjust, and have completed the present invention.
[0007]
That is, the present invention provides a fiber bundle made of acrylic fibers spun from a flat nozzle and obtained by wet spinning or semi-dry semi-wet spinning and having a flatness ratio greater than 1, in the spinning / washing step, the acrylic fibers are The temperature of the softening point of the constituting resin is −5 ° C. or higher and the melting point or lower, pressurizing the fiber bundle and pressing the fiber bundle to further flatten the acrylic fiber. It is related with the manufacturing method of the flat synthetic fiber characterized.
[0008]
As a preferred embodiment thereof, the above-mentioned production method, in which the fiber to be squeezed is a fiber spun from a flat nozzle, the flatness of the fiber after the squeezing treatment is 1.5 of the flatness of the cross section of the nozzle during spinning. It is related with the said manufacturing method characterized by being more than double, or the said manufacturing method characterized by the synthetic fiber being an acrylic fiber obtained by wet spinning or semi-dry semi-wet spinning.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in further detail below.
[0010]
The synthetic fiber in the present invention is composed of a homopolymer or a copolymer, and specific examples include acrylic fibers such as acrylic or modacrylic, vinyl chloride fibers, polyester fibers, and the like. Although not particularly limited, acrylic fibers are preferred. Acrylic fibers are usually produced by a wet or semi-dry semi-wet spinning method using a spinning stock solution in which an acrylic resin is dissolved in an organic or inorganic solvent.
[0011]
In the present invention, the fiber of the above-mentioned synthetic fiber is pressed in the production process under a condition where the temperature is 5 ° C. lower than the softening point of the resin constituting the fiber and is heated to a range below the melting point of the resin. Thus, a flat synthetic fiber having a flat cross-sectional shape is obtained. Furthermore, in the present invention, a flat synthetic fiber having an increased flatness ratio at an arbitrary magnification is obtained by performing such a pressing process on a flat synthetic fiber spun from a nozzle having a flat hole. Can do. The shape of the nozzle at this time is not particularly limited, but is preferably a rectangle or an ellipse.
[0012]
The flatness referred to in the present invention is the ratio of the minor axis to the major axis, that is, the value obtained by dividing the major axis of the sectional shape by the minor axis in the sectional shape of the synthetic fiber or the spinning nozzle. Is preferably flattening of the cross-sectional shape of synthetic fibers to be subjected to compression processing in the present invention is greater than 1 (i.e. flat cross-section), more preferably 3 or more. Although it does not specifically limit as an upper limit, Since the flat synthetic fiber of arbitrary magnifications is obtained in the process of this invention, the flatness of the base fiber may not be so high, for example, 10 or less is preferable.
[0013]
Although the temperature of the synthetic fiber at the time of pressing should just be 5 degreeC or more lower than the softening point of resin, it is better that it is more than the softening point of resin. The softening point of the resin here is a temperature at which the resin starts to soften, and specifically, a glass transition point that can be read from a DSC curve measured by a differential scanning calorimeter. If the temperature of the synthetic fiber at the time of pressing is 5 ° C. or more lower than the softening point temperature, the flatness of the fiber will hardly change even if the pressing is performed. Also, since the resin melts above the melting point, it must be below the melting point. The means for bringing the synthetic fiber to such a temperature is not particularly limited, and a known method such as a hot air device or a heat roll is used. Moreover, when manufacturing a synthetic fiber by a wet or semi-dry semi-wet spinning method, a fiber bundle can also be set to the said temperature range also by wash | cleaning under heating at the time of the water washing after spinning. This method is preferable in that it does not require another heating device.
[0014]
In the actual fiber manufacturing process, the fiber is spun in the state of a fiber bundle and passes through the subsequent steps. Therefore, the pressing treatment of the present invention is also performed in the state of the fiber bundle.
[0015]
The pressing means in the present invention is not particularly limited, and a nip roll or the like can be used. Moreover, you may have simultaneously the heating apparatus for heating or heat-retaining a fiber bundle in the temperature range mentioned above. As a pressure at the time of a pressing process, 0.05 MPa or more is preferable, More preferably, it is 0.1 MPa or more. The upper limit is not particularly limited, but about 10 MPa is sufficient. If the pressure is less than the above range, the squeezing effect is difficult to obtain, and if it exceeds the above range, the fiber is easily cut or the cross-sectional shape is difficult to maintain. The pressing treatment may be performed once at a high pressure, but may be performed a plurality of times at a low pressure, and the flatness may be adjusted by the balance between the pressure during pressing and the number of times of processing.
[0016]
By the pressing treatment of the present invention, the flatness of the fibers can be set to an arbitrary magnification. For example, if the pressing treatment is performed so that the fibers become 1.5 times or more, preferably twice or more the spinning nozzle flatness. Good. The upper limit is not particularly limited, but is preferably about 10 times.
[0017]
The pressing treatment in the present invention is usually performed in a process after spinning and washing in the synthetic fiber manufacturing process. Stretching and heat treatment, which are post-spinning treatments of ordinary synthetic fibers, are performed after the pressing treatment .
[0018]
Hereinafter, an example of a preferable method for adjusting the cross-sectional shape of the synthetic fiber of the present invention will be further described with reference to the accompanying drawings.
[0019]
FIG. 1 shows an example of an apparatus for adjusting the cross-sectional shape of the synthetic fiber. A fiber bundle 1 of synthetic fibers spun from a spinning nozzle and solidified in a coagulation bath is guided by guide rolls 2 and 3 and fed into a washing tank 4 containing washing water of a predetermined temperature. Then, the temperature of the fiber bundle is raised with the washing, and the fiber bundle is taken out from the washing tank 4 by the take-off guide rolls 6 and 7. Thereafter, the nip roll 8 is immediately pressed. If necessary, the flatness of the synthetic fiber is adjusted by repeating a series of operations of washing with water and pressing.
[0020]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
[0021]
Example 1
Spinning stock solution in which a copolymer (softening point 93 ° C.) composed of 49.5% by weight of acrylonitrile, 50.0% by weight of vinyl chloride and 0.5% by weight of sodium styrenesulfonate was dissolved in acetone at a solid content concentration of 29.5%. Was extruded from a rectangular nozzle having a nozzle diameter of 0.08 × 0.60 mm (flatness of 7.5) and 4000 holes into a 30% concentration aqueous acetone solution, and coagulation was performed by a wet spinning method. Thereafter, the synthetic fiber was heated by performing solvent washing at a water washing temperature of 95 ° C., and immediately subjected to a squeezing operation with a 0.2 MPa nip roll. As a result of alternately performing the temperature raising operation and the pressing operation five times and then performing a drying treatment, a flat synthetic fiber having a flatness ratio of about 20 as shown in FIG. 2 could be obtained.
[0022]
(Example 2)
As a result of subjecting the acrylic fiber solidified under the same conditions as in Example 1 to 95 ° C. heating operation and 0.2 MPa pressing operation alternately 10 times, followed by drying treatment, flattening as shown in FIG. A flat synthetic fiber having a rate of about 30 could be obtained.
(Example 3)
The acrylic fiber solidified under the same conditions as in Example 1 was subjected to a heating operation of 95 ° C. and a pressing operation of 0.5 MPa alternately once, and then subjected to a drying treatment. As a result, the flatness as shown in FIG. A flat synthetic fiber having a rate of about 15 could be obtained.
Example 4
Using the same undiluted solution as in Example 1, the nozzle diameter was 0.20 × 0.30 mm (flatness 1.5), extruded from a 4000 hole elliptical nozzle to a 30% concentration acetone aqueous solution, and coagulation operation was performed by wet spinning. went. Thereafter, the synthetic fiber was heated by performing solvent washing at a water washing temperature of 95 ° C., and immediately subjected to a squeezing operation with a 0.2 MPa nip roll. As a result of alternately performing the temperature raising operation and the pressing operation five times and then performing a drying treatment, a flat (elliptical) synthetic fiber having a flatness ratio of about 4.5 as shown in FIG. 5 was obtained.
(Example 5 , Reference example )
Saturated from a rectangular nozzle with a nozzle diameter of 0.08 × 0.60 mm (flatness of 7.5) and 2000 holes using a spinning stock solution in which a polymer composed of 100% by weight of vinyl alcohol is dissolved in water at a solid content concentration of 15%. It was extruded into an aqueous solution of sodium sulfate and solidified by a wet spinning method. Thereafter, after a drying, stretching, and heat treatment process, an acetalization treatment is performed at a treatment temperature of about 60 ° C. in an acetal bath of 5% formalin, 20% sulfuric acid, and 20% sodium sulfate. Then, the synthetic fiber was heated by performing a washing operation at a water washing temperature of 95 ° C., and immediately, the squeezing operation was performed with a 0.2 MPa nip roll. As a result of alternately performing the temperature raising operation and the pressing operation five times and then performing a drying treatment, a flat synthetic fiber having a flatness ratio of about 12 as shown in FIG. 6 was obtained.
[0023]
(Comparative Example 1)
As a result of treating the acrylic fiber solidified under the same conditions as in Example 1 10 times alternately with a temperature rising operation of 80 ° C. and a pressing operation of 0.2 MPa, the flatness of the nozzle as shown in FIG. Only a flat synthetic fiber having a flatness ratio of about 8 was obtained.
[0024]
【The invention's effect】
As described above, according to the present invention, in the synthetic fiber manufacturing process, the water washing temperature at the time of solvent removal is set to be equal to or higher than the softening point of the resin, and the flattening rate can be adjusted by performing the pressing treatment. Products with various flatness ratios can be manufactured without replacement, which can contribute to the improvement of productivity.
[Brief description of the drawings]
FIG. 1 shows an example of an apparatus for adjusting the cross-sectional shape of a synthetic fiber of the present invention.
2 is a schematic diagram of a cross-sectional shape of a flat synthetic fiber obtained in Example 1. FIG.
3 is a schematic diagram of a cross-sectional shape of a flat synthetic fiber obtained in Example 2. FIG.
4 is a schematic diagram of a cross-sectional shape of a flat synthetic fiber obtained in Example 3. FIG.
5 is a schematic diagram of a cross-sectional shape of a flat (elliptical) synthetic fiber obtained in Example 4. FIG.
6 is a schematic diagram of a cross-sectional shape of a flat synthetic fiber obtained in Example 5. FIG.
7 is a schematic view of a cross-sectional shape of a flat synthetic fiber obtained in Comparative Example 1. FIG.
[Explanation of symbols]
1: Fiber bundle of synthetic fibers 2, 3: Guide roll 4: Washing tank 5: Washing water 6, 7: Take-off guide roll 8: Nip roll

Claims (2)

A fiber bundle composed of acrylic fibers spun from a flat nozzle and obtained by wet spinning or semi-dry semi-moist spinning, with a flatness ratio greater than 1.
In the spinning / washing step, the temperature of the softening point of the resin constituting the acrylic fiber is −5 ° C. or higher and the melting point or lower , and pressurizing the fiber bundle by pressing in the range of 0.05 to 10 MPa , A method for producing a flat synthetic fiber, wherein the acrylic fiber is further flattened . The pressed fiber flattening of the after treatment, a manufacturing method of the flat synthetic fiber according to 請 Motomeko 1 Ru der 1.5 times or more the flattening of the nozzle section during spinning.

Images