JP3179222B2 - Easy-dying polyester fiber and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester fiber having greatly improved dyeability and a method for producing the same. More specifically, the present invention relates to an easily dyeable polyester fiber which exhibits excellent dyeing properties not only for disperse dyes but also for cationic dyes, and which can be formed into a woven or knitted fabric having an excellent texture, and a novel method for producing the same.

[0002]

2. Description of the Related Art In general, polyethylene terephthalate fiber has poor dyeability due to its dense structure.
Dyeing is carried out under conditions of high temperature and high pressure of 0 ° C. or using a carrier of an organic solvent. In cross-knitting and interweaving of polyethylene terephthalate fibers, there is no particular problem even under the above conditions, but in knitting and interweaving with wool, acrylic fiber, silk, etc., these materials deteriorate under the above conditions. Therefore, polyethylene terephthalate fibers exhibiting excellent dyeability even under milder conditions, for example, at 100 ° C. and normal pressure are required. In particular, diversification of fashion
In recent years, as individualization has progressed, cross-knitting and weaving with various fibers have increased, and the appearance of polyethylene terephthalate fibers exhibiting excellent dyeing properties even under mild conditions such as 100 ° C. and normal pressure has been desired.

In order to solve the above problem, various attempts have been made to utilize a unique microstructure obtained by an ultrahigh-speed spinning method of 7,000 m / min or more, which has been rapidly developed in recent years (for example, in the United States). Patent No. 4,195,051, U.S. Pat. No. 4,134,882, Japanese Patent Application No. 57
-89753). According to these methods, the dyeability is certainly improved, but on the other hand, the crystal in the crystal part of the fiber has a stable structure in which the crystal is largely developed, so it is difficult to shrink, and the thermal stress is also normal. Since it is considerably lower than that of the drawn yarn, the obtained woven or knitted fabric has a harder width and has a paper-like feel. In addition, 7,000m
Because of the problem of yarn breakage, polyethylene terephthalate that can be used is limited due to the problem of yarn breakage. However, there is a problem that the melt viscosity is too high and stable spinning cannot be performed.

[0004] As a cationic dyeable polyethylene terephthalate fiber exhibiting vivid dyeing properties, it is common to use polyethylene terephthalate copolymerized with a sulfonic acid metal base (for example, Japanese Patent Publication No. 34-10497). , For both disperse and cationic dyes,
In order to exhibit excellent dyeability even under mild conditions of 100 ° C. under normal pressure, it is necessary to contain a metal sulfonate group in an amount of at least 5 mol% based on the polyester acid component.

In this case, a high molecular weight polyethylene terephthalate fiber cannot be obtained due to the thickening effect of the metal sulfonate group, so that not only the mechanical properties and thermal properties inherent to the polyethylene terephthalate fiber are significantly impaired, but also Thread breaks also occur frequently in the manufacturing process of the fiber,
Further, the obtained fiber has a problem that the weaving and knitting properties are extremely poor due to the extremely large amount of fluff.

As an attempt to reduce the content of the sulfonic acid metal base and to improve the above-mentioned problems, a method of copolymerizing a high-molecular-weight polyoxyalkylene glycol (JP-A-57-63325) has been proposed. Publication) and a method of copolymerizing isophthalic acid (JP-A-58-126376, etc.) have been proposed, but the former has a problem that light resistance is poor, and the latter has insufficient dyeability. Was.

Further, Japanese Patent Application Laid-Open No. 4-194020 and the like have made attempts to improve the above problem. However, since these methods reduce the content of the sulfonic acid metal base and further copolymerize certain special components, the production cost, the polymerization rate, and the thermal stability of the polymer are not sufficient. Was not satisfactory. In addition, conventional fibers made of sulfonic acid metal base-containing polyester have a characteristic of low thermal stress, which is characteristic of copolymer fibers, and therefore, when woven or knitted, the width cannot be sufficiently increased, and the texture is reduced to paper. There was also the problem of becoming like.

[0008]

Therefore, the problems to be solved by the present invention are as follows. (1) To provide a polyester fiber which exhibits excellent dyeability under mild dyeing conditions without impairing these materials even in cross-knitting and weaving with wool, acrylic fiber, silk, etc. (2) Dispersion Providing polyester fibers showing excellent dyeability under mild dyeing conditions not only for dyes but also for cationic dyes. (3) In the case of woven or knitted fabrics, sufficient width can be provided, and paper-like feeling can be obtained. To provide a polyester fiber capable of giving a soft feeling with a bulky and soft feeling. (4) The above-mentioned polyester fiber can be prepared without copolymerizing or blending special components with 7,000 m / m.
Providing a low-cost, stable production method using relatively simple production equipment without requiring ultra-high speed spinning for more than a minute

[0009]

According to the present invention, (1)
Melts polyethylene terephthalate copolymerized with 0.8 to 3.3 mol% of sulfonic acid metal base and has a continuous cross-sectional area
Polyester fiber extruded from the expanding discharge hole
A fiber, wherein the polyester fiber has a breaking elongation of 70% or less, an amorphous part orientation degree (ΔNa) of 0.05 or less, and a thermal stress (Fmax) of 0.15 g / de or more. An easily dyeable polyester fiber is provided.

[0010] The easily dyeable polyester fiber is (2)
A polyethylene terephthalate copolymerized with 0.8 to 3.3 mol% of a sulfonic acid metal base is melted and extruded from a discharge hole having a continuously increasing cross-sectional area, and the spinning draft 1,0
At a spinning speed of 4,000 m / min or less,
Subsequently, it is manufactured by a method characterized by stretching and heat treatment.

The polyethylene terephthalate used in the present invention is a polymer having ethylene terephthalate as a repeating unit, and it is necessary to copolymerize 0.8 to 3.3 mol% of a sulfonic acid metal base. By copolymerizing the sulfonic acid metal base, not only disperse dyes but also cationic dyes can be dyed, and the content is 0.8 to 3.3 mol%, preferably 1.2 to 3.0 mol%. , More preferably 1.5 to 2.8 mol%. When the content of the sulfonic acid metal base is less than 0.8 mol%, both the disperse dye and the cationic dye have low dyeing properties under mild dyeing conditions of 100 ° C. and normal pressure, which is not preferable. On the other hand, when the content of the sulfonic acid metal base is 3.
If the amount exceeds 3 mol%, the dyeability is good, but the melt viscosity as a polymer is too high, and the spinnability is greatly reduced. In addition, the degree of polymerization of the polymer is increased due to the high melt viscosity. However, the mechanical properties and thermal properties of the obtained fiber are inferior, and there are many fluffs and the quality is greatly reduced, which is not preferable.

The intrinsic viscosity [η] c of the polymer used in the present invention is desirably 0.60 or less, preferably 0.55 or less. The intrinsic viscosity [η] c is 0.60
If the ratio exceeds the above range, the spinnability is greatly reduced due to the thickening effect of the metal sulfonate.

The sulfonic acid metal base in the present invention is not particularly limited, but, for example, a group such as a sodium salt and a potassium salt of sulfonic acid is particularly preferable from the viewpoint of economy (cost).

Specifically, for example, 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid and the like are copolymerized with polyethylene terephthalate. Of course, additives such as flame retardants, matting agents, coloring agents, or other polymers may be contained in small amounts.

Next, the polyester fiber of the present invention has an elongation at break of 70% or less, preferably 65% or less, and the degree of orientation (ΔNa) of its amorphous portion is extremely low at 0.05 or less. And its thermal stress (Fmax) is 0.1
It has a unique fiber structure of 5 g / de or more.

If the elongation at break exceeds 70%, the strength and modulus are reduced, and the yarn is stretched during weaving and knitting, and sink marks and spots are undesirably generated. On the other hand, if the degree of orientation (ΔNa) of the amorphous portion exceeds 0.05, the dyeing properties at 100 ° C. and normal pressure become insufficient, which is not preferable. Further, when the thermal stress is less than 0.15 g / de, the texture of the woven or knitted product becomes paper-like, which is inappropriate.

When the breaking elongation is as low as 70% or less,
In the conventional polyester fiber, the orientation of the fiber usually increases, and the crystal part and the amorphous part show a large degree of orientation, for example,
The degree of orientation (ΔNa) of the amorphous part is 0.08 or more.
On the other hand, the polyester fiber of the present invention has a characteristic that the degree of orientation (△ Na) of the amorphous portion is small despite the low elongation, which is completely contrary to the characteristics of the conventional polyester fiber. Have. Furthermore, surprisingly, the polyester fiber of the present invention has a thermal stress (Fmax) of:
It is as high as 0.15 g / de or more. The thermal stress reflects the thermal characteristics of the molecular chains in the amorphous part. When the degree of orientation (ΔNa) of the amorphous part is small, the thermal stress is usually small. For example, when the degree of orientation (ΔNa) of the amorphous portion is as low as 0.05 or less, the thermal stress is 0.10 g / de.
It becomes below. However, although the polyester fiber of the present invention has a low degree of orientation (ΔNa) in the amorphous part,
The thermal stress is high. "

The polyester fiber obtained by ultra-high-speed spinning at 6,000 m / min or more has a small elongation, has improved mechanical properties so that it can be used without drawing, and has an amorphous portion. Since the degree of orientation (ΔNa) is also small, the dyeing property is at a moderate level, but the value of the thermal stress is small, and the feeling of a woven or knitted product is paper-like. If the spinning speed is further increased to increase the value of the thermal stress, for example, to 9,000 m / min, the thermal stress is only about 0.13 g / de, and the spinning speed is increased to 9,000 m / min. Then, the crystal size becomes extremely developed, so that it is difficult to insert the woven or knitted fabric, and the feeling is not improved.

As described above, the polyester fiber of the present invention has a high thermal stress of 0.15 g / de or more and its crystal size is small enough to be not much different from that obtained by low-speed spinning. Since it shows a shrinkage ratio (5 to 18%), a sufficient width can be provided, and a woven or knitted fabric having an excellent texture can be obtained.

In order to exhibit excellent dyeability under mild conditions of 100 ° C. and normal pressure, the dyeing rate at 100 ° C. and normal pressure needs to be at least 70%, The polyester fiber of the present invention shows a dyeing rate of 73% or more. The dye that can be used for dyeing the polyester fiber of the present invention is not particularly limited, and commercially available disperse dyes and cationic dyes for polyester fiber can be used.

The easily dyeable polyester fiber of the present invention having such properties melts polyethylene terephthalate in which 0.8 to 3.3 mol% of a metal sulfonate is copolymerized, and its cross-sectional area is continuously enlarged. It can be obtained by extruding from a discharge hole having a shape to be drawn, taking up at a spinning draft of 10,000 or more, a spinning speed of 4,000 m / min or less, and then stretching and heat-treating. The spinning draft is a value represented by the ratio (V1 / V2) between the spinning speed (V1) and the extrusion speed (V2) of the molten polymer from the discharge hole.

In this case, as described above, the intrinsic viscosity [η] c of the polyethylene terephthalate polymer is 0.60
Or less, preferably 0.55 or less.

The spinning draft is 10,000 or more,
It is preferably 30,000 or more, more preferably 50,000.
The spinning speed must be at least 00, particularly preferably at least 100,000, and at most 4,000 m / min.

When the spinning draft is less than 10,000, the degree of orientation (ΔNa) of the amorphous portion of the drawn polyester fiber becomes larger than 0.05, and the dyeability at 100 ° C. and normal pressure is reduced. On the other hand, if the spinning speed exceeds 4,000 m / min, the yarn breaks frequently during spinning and the thermal stress value (F
max) is less than 0.15 g / de, and the texture of the woven or knitted product becomes paper-like.

As shown in FIGS. 1 and 2, a discharge hole having a continuously increasing cross-sectional area is used. FIG. 1 shows an example in which the cross-sectional area is expanded in one step, and FIG. 2 shows an example in which the cross-sectional area is expanded in two steps. , B indicate positions where the enlargement ends, and C and C ′ indicate tapered portions.

More specifically, the diameter of the discharge hole at the position A is reduced to 0.15 to 0.75 mm, and the diameter is enlarged at a gentle angle of 10 to 30 °. At the position B, the diameter is 3.0. ~ 15.
If it is 0 mm, a favorable result is obtained.

After spinning in this manner, drawing and heat treatment are performed to obtain a polyester fiber having a breaking elongation of 70% or less. The stretching and heat treatment conditions are as follows: the elongation at break of the obtained fiber is 70% or less, the degree of orientation (ΔNa) of the amorphous portion is 0.05 or less, and the thermal stress (Fmax) is determined according to the molecular orientation of the spun yarn.
Is set to be 0.15 g / de or more. For example, if the draw ratio is too high, not only the number of thread breaks increases, but also the degree of orientation (ΔNa) of the amorphous portion increases, and the dyeability greatly decreases. On the other hand, if the draw ratio is too low, the elongation at break is increased, the strength and modulus are reduced, the knitting and weaving properties are deteriorated, and the thermal stress (Fmax) is also reduced. I can't get it. Specifically, the stretching ratio is preferably about 1.3 to 1.7 times.

The method of stretching and heat treatment is not particularly limited, and even a method of once winding and then stretching and heat treating (separate rolling method) may be performed after spinning without stretching and continuous after stretching. (Direct extension method).

The easily dyeable polyester fiber thus obtained is knitted and woven, dyed and processed by a conventional method as a filament yarn or a staple fiber, and is used for various purposes including outer garments.

[0030]

The easily dyeable polyester fiber of the present invention has a good dyeability with respect to a cationic dye since it has a metal sulfonate group, and has a degree of orientation (ΔNa) of an amorphous portion.
Is low, so that the dyeability of the disperse dye is good, and the dyeability of the cationic dye is further improved.
It shows excellent dyeability even under mild conditions of normal pressure.

Further, since the thermal stress (Fmax) is large,
The woven and knitted fabric can be inserted sufficiently, and a bulky and soft texture can be obtained.

Further, since the elongation is set to 70% or less,
The yarn is not stretched during weaving or knitting, and no sink marks, spots occur, or yarn breakage occurs.

On the other hand, although it is known that the spinning draft affects the physical properties of the spun fiber, there is no report on how to drastically change the state of the polymer flow from the discharge hole.

According to the results of the study by the present inventors, it has been found that when the spinning draft exceeds 10,000, the discharge state changes drastically. That is, when the spinning draft is 10,000 or more, the swelling under the discharge hole of the molten polymer, which has been seen up to that time (basalus effect)
However, the molten polymer from the discharge hole is suddenly stretched and thinned. In particular, if the discharge holes are formed so that the cross-sectional area continuously increases, the discharge can be made more stable,
Stable spinning without breakage of yarn is possible.

In the case where the molten polymer from the discharge hole undergoes rapid elongation and thinning such that it is pulled out, it is preferable to use a polymer having a "molecular weight is not so large but the melt viscosity is moderately large". That is, in order to rapidly elongate and thin the molten polymer to pull out the molten polymer from the discharge hole and orient the polymer, if the molecular weight is too large, the entanglement of the molecular chains is too large to be oriented, and the molecular weight having a moderate entanglement Is necessary. However, if the molecular weight is too small,
Not only the mechanical properties of the obtained fiber are reduced, but also the melt viscosity is too small, so that a sufficient drawing effect cannot be obtained. From the above viewpoints, it is most effective to make a polyester having a certain molecular weight contain a specific amount of a metal sulfonate having a thickening effect.

Further, since the deformation is rapid elongation and thinning such that the molten polymer discharged from the discharge hole is pulled out, it is considered that the molecular chains of the obtained fiber are extremely highly oriented. For example, the value of the thermal stress (Fmax) which affects the width of the woven or knitted fabric and affects the excellent feeling
Shows an extremely large value.

In order to increase the value of the thermal stress (Fmax), in ordinary low-speed spinning, the orientation of the molecular chains of the fiber is poor, so that the fiber must be stretched until the elongation at break becomes considerably small. In this case, not only the production problem of yarn breakage occurs, but also the degree of orientation (ΔNa) of the amorphous portion becomes large, and the dyeing property is greatly reduced. On the other hand, in the case of the present invention, since the orientation of the molecular chain of the fiber is considerably advanced in the spinning stage, the elongation at break of the undrawn yarn becomes extremely small, and the target elongation at break is obtained by drawing. In order to achieve this, only a slight stretching is required. As a result, the degree of orientation (ΔNa) of the amorphous portion of the obtained fiber is extremely small, and since the molecular chains of the fiber are highly oriented, the value of the thermal stress (Fmax) increases.

Hereinafter, the present invention will be specifically described with reference to examples. In addition, the measuring method of the characteristic value in an Example is as follows.

(1) Intrinsic viscosity [η] c The polymer was dissolved in o-chlorophenol and measured at 35 ° C.

(2) Strength (g / de) and elongation (%) Using Tensilon (UTM-III) manufactured by Toyo Sokki Co., Ltd.
A stress-elongation curve of the multifilament is obtained at room temperature, and the value obtained by reducing the maximum stress (g) by fineness is defined as the strength (g / d).
e) The elongation at the maximum stress was defined as elongation (%).

(3) Boiling water shrinkage (BWS) (%) The fiber was treated in boiling water for 30 minutes with no load, and the fiber length before and after the treatment was determined by the following equation. BWS (%) = [(L ₀ −L ₁ ) / L ₀ ] × 100 where L ₀ : length before processing L ₁ : length after processing

(4) Specific gravity: 25 ° C. using an n-heptane / carbon tetrachloride density gradient tube
Was measured.

(5) Thermal stress (Fmax) (g / de) Using a thermal stress meter manufactured by Kanebo Engineering Co., Ltd., the maximum stress (g) was determined by measuring at a heating rate of 300 ° C./120 seconds. Was calculated from the following equation. Thermal stress (Fmax) (g / de) = maximum stress (g) / fineness (de)

(6) Amorphous part orientation (ΔNa) It was determined from the following equation. ΔNa = ΔN− (XcfcΔNc) / (1−Xc) where ΔN: birefringence of fiber obtained by a Bellec compensator method using a polarizing microscope ΔNc: intrinsic birefringence of crystal (= 0.212) Xc : Crystallinity determined by the specific gravity method, which is determined by the following equation.

Xc = (0.7491-1 / ρ) /0.0
6178 indicates the specific gravity of the fiber. 3 fc: a crystal orientation function, which is obtained as follows from an average orientation angle θ determined by wide-angle X-ray diffraction. fc = (180−θ) / 180 where θ is obtained from the half width of the [010] and [100] diffraction arcs.

(7) Crystal Size The crystal size was determined from the half width of the intensity distribution curve of the equator scan obtained by wide-angle X-ray scattering using the Scherrer equation.

(8) L * L * was measured using a Macbeth MS2020 spectrophotometer.

(9) Dyeing ratio The absorbance of the dye solution before and after dyeing was measured using a Hitachi 330 automatic spectrophotometer, and calculated by the following equation. Dyeing ratio (%) = [(AB) / A] × 100 where A: absorbance of stain before staining B: absorbance of stain after staining

(10) Spinning condition Spinning was continued for 5 hours, and the spinning condition was determined to be good when the yarn was cut twice or less, and poor when the yarn was cut twice or more.

(11) Hand After bulk knitting, the dyed sample was evaluated for bulkiness and softness by touch.

[0051]

Embodiment 1 As shown in FIG. 1, a discharge hole whose cross-sectional area continuously increases (the diameter of the enlargement start position is 0.20 mm, 18 °)
(The diameter at the end of the enlargement is 10.00mm)
And a limiting viscosity [η] c of 0.47 and 5-sodium sulfoisophthalic acid.
30 mol% of polyethylene terephthalate copolymerized with 30 mol%
Melted at 0 ° C., extruded at a discharge rate of 21.7 g / min, cooled, solidified, applied with an oil agent, turned eight times on a first roller at a speed of 2,000 m / min, at a temperature of 100 ° C., and subsequently wound up Speed, 2,600m / min, temperature 150 ℃
Turned 8 times on a second roller, and continuously heat-stretched, wound up at 2,600 m / min, and 75de / 16fi
1 s of multifilament was obtained. The spinning draft at this time was an extremely high draft of 138,000,
Because the above-mentioned cross-sectional area uses the discharge hole which continuously increases,
The discharge is extremely stable (spinning property: good),
In addition, the discharge state exhibited a rapid elongation and thinning without a bales effect, as if the molten polymer was pulled out of the discharge hole at once. Table 1 shows the properties of the obtained multifilament yarn.

[0052]

[Table 1]

The obtained fiber had a low specific gravity and low crystallinity as a whole fiber, but due to its crystal size, crystals had developed to the extent of a normal drawn yarn. Furthermore, despite the drawn heat-treated yarn, the orientation (ΔNa) of the non-crystalline portion is as low as that of the undrawn yarn, and more surprisingly,
The thermal stress was almost the same as that of a normal undrawn yarn.

The above multifilament yarn is knitted in a tube,
After scouring, dyeing was performed by presetting at 180 ° C. for 30 seconds. Refining conditions (1) Score roll 400 0.5 g / l (2) Sodium carbonate 0.5 g / l (3) Temperature 70 ° C. Dyeing conditions (1) Dye Eastman Po
lyster Blue GLF (2) Dye concentration 4% owf (3) Disper VG 0.5 g / l (4) Acetic acid 0.3 cc / l (5) Bath ratio 1: 100 (6) Temperature boiling (7) Pressure Normal pressure ( 8) Staining time 60 minutes

Next, the sample was washed with water, subjected to a reduction treatment, washed with water, dehydrated, and set at 160 ° C. for 1 minute to obtain a sample for evaluation of dyeability and feeling. Reduction conditions (1) Hydrosulfite 2 g / l (4) Temperature 80 ° C. (2) NaOH 2 g / l (5) Time 30 minutes (3) Amyrazine 2 g / l The evaluation results of the staining properties are shown in Table 2. In order to compare the dyeability levels, the values of a sample obtained by spin-drawing a normal polyethylene terephthalate homopolymer by an ordinary method and dyeing at 130 ° C. under high pressure are also shown as a reference example.

[0056]

[Table 2]

The above-mentioned sample shows extremely excellent dyeability under the extremely mild conditions of 100 ° C. and normal pressure, and the degree of the dyeability is comparable to that of the conventional dyeing at 130 ° C. Was. The texture was bulky with sufficient width, and the modulus was low and soft because the orientation (ΔNa) of the amorphous portion was low.

Subsequent to dyeing with a disperse dye, dyeing was performed with a cationic dye in the following manner. Refining conditions (1) Score roll 400 0.5 g / l (2) Sodium carbonate 0.5 g / l (3) Temperature 70 ° C Dyeing conditions (1) Dye ESTROL RED
NGSL (2) dye concentration 4% owf (3) acetic acid 0.3 cc / l (4) anhydrous sodium sulfate 3 g / l (5) bath ratio 1: 100 (6) temperature boiling (7) pressure normal pressure (8) dyeing Time 60 minutes

Next, the sample was washed with water, subjected to a soaping treatment under the following conditions, washed with water, dehydrated, and set at 160 ° C. for 1 minute to obtain a sample for evaluation of dyeability and hand. Soaping conditions (1) Score roll 1 g / l (2) Temperature 70 ° C. (3) Time 10 minutes The dyeing result of the obtained sample is as follows: L * is 27.4, dyeing rate is 85%, and cationic dye is used. Even when used, it exhibited excellent dyeability under mild conditions of 100 ° C. and normal pressure.
The hand was bulky and soft, like the sample obtained by dyeing with a disperse dye.

As described above, the fiber of the present invention exhibits excellent dyeing properties for both disperse dyes and cationic dyes, has a good feeling, and is easy to produce. Met.

[0061]

Comparative Example 1 A discharge hole having a constant cross-sectional area (having a diameter of 0.04
mm, a land length of 0.80 mm), and spinning was performed in the same manner as in Example 1 except that the discharge rate was 30.0 g / min and the speed of the second roller was 3,600 m / min. Then, a multifilament yarn of 75de / 16fils was obtained. At this time, the spinning draft was 161 and the discharge state showed a normal so-called “basalus effect”. Table 3 shows the properties of the obtained multifilament yarn.

[0062]

[Table 3]

In the obtained multifilament yarn, although the degree of orientation (ΔNa) of the amorphous portion is low, the multifilament yarn still has a low degree of orientation.
The value was larger than 05, and the thermal stress was not high. In addition, from the specific gravity and crystal size, the crystallinity was not different from ordinary drawn yarn. The multifilament yarn was knitted in a tube and dyed with a disperse dye and a cationic dye in the same manner as in Example 1, and the dyeability and hand were examined. Table 4 shows the evaluation results of the dyeability.

[0064]

[Table 4]

5-sodium sulfoisophthalic acid
Since it is a 6 mol% copolymerized polyethylene terephthalate, the dyeability is better than ordinary polyethylene terephthalate, but the level is insufficient for both dyes. The hand was paper-like and hard.

[0066]

COMPARATIVE EXAMPLE 2 Discharge holes having a constant cross-sectional area (diameter 0.22
mm, land length 0.60 mm) using a polyethylene terephthalate homopolymer having an intrinsic viscosity [η] c of 0.64 and containing no copolymerization component.
After melting at 0 ° C., extruding at a discharge rate of 62.5 g / min, cooling and solidifying, applying an oil agent, converging the multifilament yarn to minimize air resistance, and then drawing,
7,500m without any heat treatment
At a speed of / min to obtain a multifilament yarn of 75de / 16fils. The spinning draft at this time was 88. The properties of the obtained multifilament yarn were as shown in Table 5.

[0067]

[Table 5]

Although the obtained multifilament yarn was a highly crystalline multifilament yarn in which crystals were extremely developed, the degree of orientation (ΔNa) of the amorphous portion was low and the thermal stress was small. The multifilament yarn was knitted in a tube and dyed with a disperse dye in the same manner as in Example 1. The dyeability and hand were examined. The L * was 25.8, the dyeing rate was 87%, and the dyeing rate was 10%.
Even under mild conditions of 0 ° C. and normal pressure, excellent dyeability was exhibited, but the width of the tubular knitting was small and the paper-like feeling was obtained. Further, since 5-sodium sulfoisophthalic acid was not copolymerized, the dye was not dyed at all with the cationic dye.

[0069]

Comparative Example 3 Spinning was performed under the same conditions as in Comparative Example 2 except that the polymer was changed to polyethylene terephthalate copolymerized with 2.6 mol% of 5-sodium sulfoisophthalic acid. I couldn't take it up.

[0070]

Examples 2 to 4 and Comparative Examples 4 and 5
Table 6 shows the copolymerization amount of 5-sodium sulfoisophthalic acid.
In the same manner as in Example 1 except that a multifilament yarn of 75 de / 16 films was obtained.

[0071]

[Table 6]

Table 7 shows the spinnability of each multifilament yarn and the properties of each obtained multifilament yarn.

[0073]

[Table 7]

These multifilament yarns were knitted in a tube, dyed with a disperse dye in the same manner as in Example 1, and evaluated for dyeability and feeling. The results were as shown in Table 8.

[0075]

[Table 8]

In the case of Comparative Example 4, since the amount of copolymerization was small, the dyeability was insufficient, and the feeling was hard, which was not preferable. In the case of Comparative Example 5, extremely excellent dyeability was exhibited, and the texture was also bulky and soft. However, since the amount of copolymerization was large, the melt viscosity was too high, and the spinnability was extremely poor. In addition, the obtained multifilament yarn had low strength and more fluff.

In the case of Examples 2 to 4, both the spinnability and the dyeability were good, and the feeling was bulky and soft.

[0078]

Comparative Example 6 A multifilament of 75 de / 16 films was obtained in the same manner as in Example 1 except that the discharge rate was 20 g / min, the speed of the second roller was 2,400 m / min, and the other conditions were the same as in Example 1. The spinning draft at this time is 150,000
It was 0. The properties of the obtained multifilament yarn are
As shown in Table 9.

[0079]

[Table 9]

An attempt was made to knit this multifilament yarn and dye it to evaluate the dyeing properties and hand. However, the breaking elongation was too high and the strength was too low, and many yarn breaks occurred during knitting. , Could not be evaluated sufficiently.

[0081]

The easily dyeable polyester fiber of the present invention shows excellent dyeability to both cationic dyes and disperse dyes under mild dyeing conditions. Further, a woven / knitted fabric having a bulky, soft, and excellent texture without a paper-like feeling can be obtained.

Further, according to the method for producing an easily dyeable polyester fiber of the present invention, it is possible to use relatively simple production equipment without copolymerizing or blending special components, and without requiring super high speed spinning. The above-mentioned easily dyeable polyester fiber can be manufactured stably at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a discharge hole used in the method of the present invention.

FIG. 2 is a cross-sectional view showing another example of a discharge hole used in the method of the present invention.

[Explanation of symbols]

 A A position where the cross-sectional area continuously starts expanding B A position where the cross-sectional area ends expanding C, C 'Taper portion

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-53-139820 (JP, A) JP-A-2-307971 (JP, A) JP-A-5-132810 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) D01F 6/84 305 D01F 6/62 301 D01F 6/62 302 D01D 4/02

Claims (3)

(57) [Claims] 1. Polyethylene terephthalate copolymerized with 0.8 to 3.3 mol% of a metal sulfonate group is melted.
Do not extrude from the discharge hole whose cross-sectional area increases continuously.
Polyester fiber having a breaking elongation of 70% or less and a degree of orientation (ΔNa) of an amorphous portion of 0.1%.
An easily dyeable polyester fiber having a thermal stress (Fmax) of not more than 0.15 g / de or less. 2. Melting polyethylene terephthalate copolymerized with 0.8 to 3.3 mol% of a metal sulfonate,
A process for producing an easily dyeable polyester fiber, comprising: extruding from a discharge hole having a continuously increasing cross-sectional area, taking up at a spinning draft of 10,000 or more, a spinning speed of 4,000 m / min or less, and then drawing and heat-treating. 3. The method for producing an easily dyeable polyester fiber according to claim 2, wherein the intrinsic viscosity [η] c of the polyethylene terephthalate is 0.60 or less.