JP3570171B2 - Method for producing core-sheath composite fiber and method for producing false twisted yarn comprising the same - Google Patents

Description

【表２】

【００５２】
【発明の効果】
本発明の芯鞘複合繊維の製造法を採用することにより、単位時間当たりの吐出量を大幅に増加させることができ、しかも発色性、耐摩耗特性等の従来技術の欠点を克服することができる。換言すれば、ポリエチレンテレフタレートを高速紡糸する際に生じる繊維の発色性、染め斑および耐摩耗特性の問題点を解決できるものである。
【図面の簡単な説明】
【図１】本発明の実施例および比較例において、紡糸速度６０００ｍ／分で紡糸して得られた繊維の応力−伸長曲線を示す図である。
【図２】本発明の実施例および比較例において、紡糸速度１００００ｍ／分で紡糸して得られた繊維の応力−伸長曲線を示す図である。
【符号の説明】
Ａ ５−ナトリウムスルホイソフタル酸共重合ポリエステルを芯、ホモＰＥＴを鞘とした芯鞘複合繊維
Ｂ ＰＥＴ単独繊維[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a core-in-sheath conjugate fiber in which productivity is improved by increasing the discharge amount, and in which the quality such as coloring property, spots and abrasion resistance is improved.
[0002]
[Prior art]
Polyethylene terephthalate (hereinafter abbreviated as PET) fibers have various excellent properties including mechanical properties, and are therefore widely used not only for clothing but also for industrial materials.
[0003]
In recent years, in the production of PET fibers, a high-speed spinning method in which a take-up speed in spinning is as high as 5,000 m / min or more and a practical fiber is obtained in one step without going through a drawing step has been industrially adopted. . Since the productivity in the spinning process greatly depends on the discharge amount per unit time, the higher the speed, the higher the productivity of such a one-step method.
[0004]
However, in the high-speed spinning method, PET fibers exhibit practically preferable mechanical properties at a spinning speed of about 6,000 to 7000 m / min, but when the speed is further increased, the strong elongation is reduced, which causes a problem in practical use. Therefore, there is a limit to sufficiently exhibit the effect of improving productivity.
[0005]
Therefore, if it is possible to obtain a fiber having a larger residual elongation while suppressing the molecular orientation even at the same spinning speed, it is possible to further increase the spinning speed, that is, to increase the discharge rate, thereby increasing the production efficiency.
[0006]
In this regard, Japanese Patent Application Laid-Open No. 8-246247 discloses that by combining PET with polystyrene, polymethyl methacrylate, polymethyl pentene, or the like as a core component, the residual elongation of the obtained fiber is increased, and the production of spun yarn is increased. It has been shown that the performance is greatly improved. However, it has been found that these polymers listed as the core component do not dye with ordinary dyes for PET, and thus cause problems in the coloring properties of dyed products and cause spotting. In addition, it has been found that since peeling occurs at the core-sheath interface after dyeing, sheath cracking and fibrillation easily occur due to friction, and there is a problem in abrasion resistance.
[0007]
[Problems to be solved by the invention]
The present invention has been obtained as a result of repeated studies in order to improve the productivity by increasing the discharge amount and to solve the problems of the coloring property, the spots of stain, and the abrasion resistance.
[0008]
In other words, it is an object of the present invention to solve the problems of the color developing property, dye spots, and abrasion resistance of the fibers generated when the PET is spun at a high speed.
[0009]
[Means for Solving the Problems]
An object of the present invention is to provide a polyester in which a sheath component is substantially composed of polyethylene terephthalate, a core component in which polyester having 5-sodium sulfoisophthalic acid copolymerized in an amount of 2 to 15 mol%, and a core component composite ratio of 1 to 15% by weight. % Of the core-sheath conjugate fiber at a spinning speed of 4000 to 12000 m / min.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
[0011]
PET in the sheath component may be one in which a part of the diol component and a part of the acid component are each substituted with another copolymerizable component in a range of 15 mol% or less. They may also contain additives such as matting agents, flame retardants, antistatic agents, pigments and the like.
[0012]
If the core component polymer is a polyester in which 5-sodium sulfoisophthalic acid is copolymerized in an amount of 2 to 15 mol%, both high spinning speed, dyeability and abrasion resistance can be achieved.
[0013]
The higher the copolymerization rate of 5-sodium sulfoisophthalic acid is, the higher the productivity improvement effect is preferable. However, if the copolymerization rate is excessively increased, a sharp increase in viscosity occurs in the polymerization process, and the polymerization degree of the polymer may be increased. The problem that it cannot be done arises. Further, the thermal stability of the polymer is also reduced, so that the spinnability is deteriorated. If the copolymerization ratio of 5-sodium sulfoisophthalic acid is 2 to 15 mol%, the spinnability is good. Preferably it is 5 to 12 mol%.
[0014]
The core component polymer may be copolymerized with isophthalic acid in addition to 5-sodium sulfoisophthalic acid as long as the present invention can be achieved.
[0015]
In the present invention, the copolymerization ratio of 5-sodium sulfoisophthalic acid means a molar ratio of 5-sodium sulfoisophthalic acid to all acid components in the polymer.
[0016]
The core component polymer may be a 5-sodium sulfoisophthalic acid copolymerized polyester alone, or may be a mixture with another polymer such as nylon as long as the effects of the present invention are exhibited.
[0017]
The shape of the core-sheath is not particularly limited, and may be a concentric core-sheath or an eccentric core-sheath, a shape having a plurality of cores, or a sea-island structure. That is, it is preferable that the core component polymer is continuously present in a constant amount in the fiber axis direction and is not exposed on the fiber surface. Therefore, the core polymer is preferably a concentric core-sheath collected at the center as much as possible from the viewpoints of coloring properties and abrasion resistance.
[0018]
When the 5-sodium sulfoisophthalic acid copolymerized polyester is on the sheath side, the sheath side is rapidly cooled in the high-speed spinning process, so that the adverse effect of the copolymerized polymer is likely to be manifested, and spinning malfunctions or defects such as microvoids in the obtained fiber are caused. , A large amount of steel is generated and the material becomes brittle, so that the effect of improving the residual elongation is not exhibited, and the strength is further reduced. The adverse effect of this quenching is not so significant in the case of low-speed spinning, but the effect increases rapidly as the spinning speed increases. It is described in "HIGH-SPEED FIBER SPINNING", p. 447 (WILEY-INTERSCIENCE) or the like that high-speed spinning reduces the fiber properties of even a homo-PET single yarn by rapid cooling. For this reason, special care must be taken when high-speed spinning is performed using a copolymerized polyester polymer as in the present invention. In particular, when the spinning speed is 6000 m / min or more, it is almost difficult to obtain practically usable fibers when the copolyester is used as a sheath. Actually, high-speed spinning using 5-sodium sulfoisophthalic acid copolymerized polyester as the sheath side is disclosed in JP-A-64-14333 and JP-A-5-9855. The effect of increasing the residual elongation of the obtained fiber is not only not recognized, but also the strength is low and it is difficult to use it as a filament for clothing or industrial material.
[0019]
If the fiber obtained by spinning has the property of a so-called highly oriented undrawn yarn (POY) having a residual elongation of 70% or more, it is preferable to further draw or draw false twist. Considering the processability and process stability at that time, it is considered that the obtained fiber should be oriented to some extent. Therefore, the spinning speed is preferably 4000 m / min or more.
[0020]
Usually, highly oriented undrawn yarn of PET for drawing false twisting is produced at a spinning speed of about 3000 m / min. Although drawing false twisting is not impossible even with a fiber obtained at a spinning speed of 4000 m / min, the residual elongation of the obtained processed yarn is excessively reduced, so that compared to a fiber obtained at a spinning speed of 3000 m / min. It is necessary to greatly reduce the draw ratio. Therefore, the overall productivity of spinning / drawing false twisting does not necessarily increase and is not preferable. In addition, when processing is performed with a high draw ratio to match the productivity, the tension of the twisted / untwisted portion is excessively increased, so that fluffing and yarn breakage are likely to occur, and the operability of the draw false twisting process is reduced. .
[0021]
In contrast, in the present invention, by arranging the 5-sodium sulfoisophthalic acid copolymerized polyester as the core of the specific amount of the conjugate fiber, the degree of orientation of the highly oriented undrawn yarn obtained even at a high spinning speed is suppressed, This improves the productivity of spinning / drawing false twisting.
[0022]
On the other hand, a fiber obtained by spinning and having a residual elongation of less than 70% can be used for clothing without any special stretching step. At this time, the spinning speed is preferably 8000 m / min or more from the viewpoint of productivity. ADVANTAGE OF THE INVENTION According to this invention, even if the spinning speed is 10000 m / min or more, the drop in the high elongation is small, and the fiber which can be practically used for clothing is not limited to the spinning speed of 8000 m / min, which was conventionally low in the strength and unpractical. Can be obtained. Then, the fiber obtained by the high-speed spinning can be subjected to false twisting.
[0023]
The above-described effect of suppressing the increase in the degree of orientation is 1% by weight or more, preferably 3% by weight or more, as a composite ratio of the core component depending on the purpose. If the core component composite ratio is less than 1% by weight, a sufficient orientation suppressing effect cannot be expected. On the other hand, as the core component composite ratio is increased, the effect of suppressing the orientation becomes remarkable. However, considering the strength of the final product, fiber cross-section deformation during false twisting, heat setting property, and the like, 15% by weight or less, preferably 10% by weight or less. % By weight or less.
[0024]
In the present invention, since a relatively small amount of the copolyester is disposed on the core, troubles such as fusion do not occur even when high-temperature heat treatment is performed. In addition, since it has high compatibility with the sheath component PET, there is no occurrence of peeling at the core / sheath interface, and the wear resistance is good. Further, the core component has higher dyeability than the sheath component, and not only improves the color development, but also improves the discoloration characteristics (frosting characteristics) due to friction.
[0025]
5-Sodium sulfoisophthalic acid is a very well-known polymer for modifying PET. The copolymer is widely used for the purpose of improving dyeability, alkali elution property and the like. However, in the case of composite fibers, 5-sodium sulfoisophthalic acid copolymerized polyester is mostly used for the sheath portion in order to impart functionality to the fiber, and as in the present invention, 5-sodium sulfoisophthalic acid copolymerized polyester is used. The effect of suppressing the orientation of the PET fiber only by compounding a specific amount was not known at all.
[0026]
As described above, it is not clear why the 5-sodium sulfoisophthalic acid copolymerized polyester suppresses the orientation of PET by high-speed spinning and increases the residual elongation of the obtained fiber. It is thought that this influences the thinning behavior and reduces the internal stress when the oriented structure of the sheath PET is formed, thereby suppressing the orientation of the PET.
[0027]
According to the present invention, even at a high speed spinning of 4000 to 6000 m / min, the obtained fiber can be drawn (false twisted) at a draw ratio of 1.2 to 2.0 times, and is superior in productivity to the conventional one. It is a manufacturing method. Further, in the high-speed spinning of PET alone, the fiber obtained at a spinning speed of 8000 m / min or more is inferior in the high elongation characteristic, whereas in the method of the present invention, the practical high elongation characteristic is obtained even at the spinning speed of 8000 m / min or more. This is a production method which is superior in productivity to the conventional one even in ultra high speed spinning.
[0028]
The polyester fiber obtained by the present invention, as raw silk, or as a twisted yarn or false twisted yarn, is used for clothing such as lining, sportswear, slacks, blousons, blouses, and for materials such as ribbons, tapes and belts. It can be suitably used.
[0029]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples.
[0030]
In addition, the following method was used for the measuring method in an Example.
[0031]
A. Intrinsic viscosity [η]
Measured in orthochlorophenol at 25 ° C.
[0032]
B. Stress-elongation curve, strength and elongation A load-elongation curve was determined according to JIS L1013.
[0033]
Next, the load value was divided by the initial fineness, which was taken as stress (strength), the elongation was divided by the initial sample length, and a stress-elongation curve consisting of strength and elongation was obtained.
[0034]
C. After the dyed fiber was knitted in a tube, the dyed fiber was dyed with Terrasil Navy Blue SGL, and the color development and the sensory evaluation of spots were performed.
[0035]
D. The knitted fabric after knitting, dyeing and rubbing the abrasion resistant fibers was subjected to a sensory evaluation.
[0036]
Example 1
A homopolyester having an intrinsic viscosity of 0.63 and a copolymerized polyester having an intrinsic viscosity of 0.63 obtained by copolymerizing 12 mol% of 5-sodium sulfoisophthalic acid are separately melted, and filtered through a stainless steel nonwoven filter having an absolute filtration diameter of 5 μm. Then, a copolyester core and a homo-PET core / sheath composite on a concentric sheath were discharged from a die having a hole diameter of 0.25 mm and 36 holes. At this time, the composite ratio of the core component was 8% by weight. The spinning temperature was adjusted to 295 ° C., and the discharge rate was adjusted to a single yarn fineness of 4 dtex. The discharged yarn was cooled by a conventional method after discharge, lubricated after refueling, and wound up by a winding machine via a take-off roller. The peripheral speed of the take-off roller that the yarn first touches is shown in Table 1 as the spinning speed (Experiment Nos. 1 to 5). At this time, the stress-elongation curves of the fibers obtained at spinning speeds of 6000 m / min and 10000 m / min are shown in curve A of FIG. 1 and curve A of FIG. 2, respectively. Table 1 shows the strength and elongation. FIG. 1 and FIG. The results for the 10 and 12 uncopolymerized PET-only yarns are shown as curve B, respectively.
[0037]
Even at a spinning speed of 6000 m / min (FIG. 1A), unlike the case of PET alone (Comparative Example 1, FIG. 1B), the conjugate fiber of the present invention has a constant stress extension region and is an undrawn yarn. Furthermore, even at a spinning speed of 10000 m / min (FIG. 2A), it can be seen that unlike the case of PET alone (Comparative Example 1, FIG. 2B), it has good high elongation characteristics. Further, as can be seen from Table 1, when 5-sodium sulfoisophthalic acid copolymerized polyester was combined with homo-PET, the effect of improving elongation over the entire spinning speed region as compared with PET alone yarn (Experiment Nos. 9 to 13). was gotten.
[0038]
The fibers obtained at spinning speeds of 4000 and 6000 m / min were subjected to draw false twisting at a heater temperature of 220 ° C. and draw ratios of 1.95 and 1.68, respectively. Table 2 shows the coloring properties, spots and abrasion resistance of the stretched false twisted fiber and the fiber itself obtained at a spinning speed of 8000 to 12000 m / min. Both the drawn false twisted fiber and the ultrahigh-speed spun fiber having a spinning speed of 8000 m / min or more had good color developability, spotted spots and abrasion resistance.
[0039]
Example 2
Melt spinning was carried out under the same conditions as in Example 1 (Experiment No. 2) except that the copolymerized polyester was changed to 5-sodium sulfoisophthalic acid 6 mol% copolymer (intrinsic viscosity 0.65) (Experiment No. 6). ). Table 1 shows the strength and elongation. At this time, the elongation improvement effect was also observed. Further, at a heater temperature of 220 ° C. and a draw ratio of 1.32 times, the fiber was subjected to draw false twisting. The color development, dyeing spots and abrasion resistance of the drawn false twisted fiber were also good (Table 2).
[0040]
Example 3
Melt spinning was performed (Experiment No. 7) under the same conditions as in Example 1 (Experiment No. 2) except that the copolymerized polyester was changed to 5-sodium sulfoisophthalic acid 2 mol% copolymer (intrinsic viscosity: 0.65). Table 1 shows the strength and elongation. At this time, the effect of improving the elongation is small, but it can be seen that the strength is improved as compared with that of Example 1 having the same spinning speed. In addition, this fiber was subjected to draw false twisting at a heater temperature of 220 ° C. and a draw ratio of 1.22 times. The color development, dyeing spots and abrasion resistance of the drawn false twisted fiber were also good (Table 2).
[0041]
Example 4
Spinning was carried out under the same conditions as in Example 1 (Experiment No. 2) except that the copolymerization ratio of 5-sodium sulfoisophthalic acid was changed to 10 mol%, and isophthalic acid was further copolymerized to 20 mol (intrinsic viscosity: 0.60). (Experiment No. 8). Table 1 shows the strength and elongation. At this time, the elongation improvement effect was also observed. In addition, drawing false twisting of this fiber was performed at a heater temperature of 220 ° C. and a draw ratio of 1.60. The color development, dyeing spots and abrasion resistance of the drawn false twisted fiber were also good (Table 2).
[0042]
Comparative Example 1
The polymer was only the homo-PET used in Example 1, and the single yarn was melt-spun under the same conditions as in Example 1 without using composite spinning (Experiments Nos. 9 to 13). The strength and elongation are shown in Table 1.
[0043]
The stress-elongation curves of the fibers obtained at spinning speeds of 6000 m / min and 10000 m / min are shown in curve B of FIG. 1 and curve B of FIG. 2, respectively. Both show typical characteristics of PET fibers, and it can be seen that at a spinning speed of 6000 m / min, stretching has already occurred up to winding and has no constant stress elongation region and is not an undrawn yarn.
[0044]
At a spinning speed of 10,000 m / min, unlike the case of 12 mol% of 5-sodium sulfoisophthalic acid copolymerized polyester composite, it has a high elongation characteristic that does not endure practical use. In addition, although the fiber obtained at a heater temperature of 220 ° C. and a draw ratio of 1.32 times at a spinning speed of 4000 m / min was subjected to drawing false twisting, fluffing occurred frequently during processing. Table 2 shows the coloring properties, spots of stain, and abrasion resistance of the drawn false twisted fibers.
[0045]
Example 5
Melt spinning was performed under the same conditions as in Example 1 (No. 2) except that the composite ratio of the copolymerized polyester was 5 and 14% by weight (Experiment Nos. 14 and 15). Table 1 shows the strength and elongation. It can be seen that the larger the composite ratio, the greater the elongation improvement effect. Further, at a heater temperature of 220 ° C., a 5% by weight composite fiber was subjected to draw false twisting at a draw ratio of 1.32 times, and a 14% by weight composite fiber at a draw ratio of 1.94 times.
[0046]
The color development, dyeing spots and abrasion resistance of the drawn false twisted fiber were also good (Table 2).
[0047]
Comparative Example 2
Spinning was performed under the same conditions as in Example 1 (Experiment No. 2) except that the copolymerization ratio of 5-sodium sulfoisophthalic acid was set to 1 (intrinsic viscosity 0.65) and 17 mol% (intrinsic viscosity 0.57). (Experiment Nos. 16 and 17). The strength and elongation are shown in Table 1. At a copolymerization ratio of 1 mol%, the elongation improving effect was hardly observed. At a copolymerization rate of 17 mol%, the effect of improving elongation was large, but the spinning condition was poor and the number of yarn breaks occurred frequently, and the strength of the obtained fiber was also low.
[0048]
Comparative Example 3
Spinning was performed under the same conditions as in Example 2 (Experiment No. 6) except that the composite ratio of the copolymerized polyester was changed to 18% by weight (Experiment No. 18). The strength and elongation are shown in Table 1. Although the elongation improvement effect was great, the spinning condition was slightly poor. This fiber was subjected to draw false twisting at a heater temperature of 220 ° C. and a factor of 1.95. However, fluffing occurred frequently during processing, and the coloring property, spots of staining, and abrasion resistance were poor (Table 2). Further, the strength of the drawn false twisted yarn was excessively reduced, and the cross-sectional deformation was too large. There were also disadvantages such as.
[0049]
Comparative Example 4
Melt spinning was carried out under the same conditions as in Example 3 except that the core polymer and the sheath polymer of Example 3 were replaced and the sheath polymer (2-sodium sulfoisophthalic acid 2 mol% copolymerization) composite ratio was 10% by weight. (Experiment No. 19). At this time, not only the elongation was hardly improved but also the strength was significantly reduced (Table 1). Further, the spinning was abnormal, and the yarn was frequently broken.
[0050]
Comparative Example 5
Melt spinning was performed at a spinning speed of 6000 m / min under the same conditions as in Example 1 except that the core polymer of Example 1 (12 mol% of 5-sodium sulfoisophthalic acid copolymer) was not a composite but a blend. No. 20). At this time, a slight elongation improvement effect was observed, but the spinning was abnormal, and the yarn was frequently broken.
[0051]
[Table 1]

[Table 2]

[0052]
【The invention's effect】
By employing the method for producing the core-sheath conjugate fiber of the present invention, the discharge amount per unit time can be greatly increased, and the drawbacks of the prior art such as coloring property and abrasion resistance can be overcome. . In other words, the present invention can solve the problems of the color developing property, spots of staining, and abrasion resistance of the fiber which occur when spinning polyethylene terephthalate at a high speed.
[Brief description of the drawings]
FIG. 1 is a view showing a stress-elongation curve of a fiber obtained by spinning at a spinning speed of 6000 m / min in Examples and Comparative Examples of the present invention.
FIG. 2 is a view showing a stress-elongation curve of a fiber obtained by spinning at a spinning speed of 10,000 m / min in Examples and Comparative Examples of the present invention.
[Explanation of symbols]
A core-sheath composite fiber B having 5-sodium sulfoisophthalic acid copolymerized polyester core and homo PET sheath B PET single fiber

Claims (2)

A core-sheath composite in which the sheath component is substantially composed of polyethylene terephthalate, and the core component is a polyester in which 5-sodium sulfoisophthalic acid is copolymerized with 2 to 15 mol%, and the core component composite ratio is 1 to 15% by weight. A method for producing a core-sheath composite fiber, comprising spinning the fiber at a spinning speed of 4000 to 12000 m / min. A method for producing a false twisted yarn comprising a core-sheath composite fiber, wherein the fiber obtained by the production method according to claim 1 is subjected to false twisting.

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