JP2006225768A - Easily dyeable polyester fiber and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polyester fiber having excellent dyeability and a soft feeling. <P>SOLUTION: The easily dyeable polyester fiber is a polyester obtained by copolymerizing a polyethylene terephthalate with 3-6 wt.% of a polyethylene glycol having 300-2,000 molecular weight, has ≤1.4 single filament decitex and satisfies that (a) a fineness deviation value U% is ≤1.0%, the maximum of variation coefficient CV value in a period of 10-80 m by a fineness fluctuation frequency analysis is ≤0.3% (the fineness deviation value U% is measured in 500 m yarn length) and (b) a temperature (Tmax) at which a dynamic loss tangent (tanδ) measured at 110 Hz wavelength exhibits the maximum is 85°C≤(Tmax)≤105°C. The spinning is carried out at spinning hole distances of ≥8 mm and ≤30 mm, at a discharge linear velocity at a spinning hole outlet of ≥0.2 m/second and ≤1.0 m/second and a winding speed of ≥5,000 m/minute. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyester fiber which is easily dyeable, has fine fineness and flexibility, and has few fineness spots and dyeing spots, and a method for producing the same. More specifically, it is a polyester fiber by a high-speed spinning method that does not require a drawing process and is suitable for making a fabric excellent in easy dyeability and flexibility that can be used in the inner field, sports field, etc. The present invention relates to a polyester fiber having a single yarn decitex of 1.4 or less and a method for producing the same, having a high quality dyeability with few defects such as yarn breakage and knurls at the time of spinning and few fineness spots.

In general, polyesters, particularly polyesters having polyethylene terephthalate as a structural unit, are used in a wide range of fields such as fibers, resins, and films because they have excellent mechanical properties and chemical properties.
However, such polyesters also have no affinity for ionic dyes such as acid dyes and basic dyes in terms of dyeability, and even in practically used disperse dyes, high-temperature and high-pressure dyeing is possible due to their dense molecular structure. Have the disadvantage of requiring
Conventionally, polyester fibers have been used in combination with various fiber materials. The purpose of these composites is to make up for the disadvantages of each material and to provide comprehensively superior fiber materials by taking advantage of the advantages. Improvement of dyeability, which is the greatest disadvantage of polyester, is indispensable. It can be said that it is an element.

Furthermore, in recent years, with improved dyeability of polyester fibers, the hardness of the texture has been improved, soft texture in knitting and knitting with wool and silk, knitting with cellulose fibers, knitting with polyurethane fibers, etc. There is also an increasing need for polyester fibers that do not impede. Fabrics made from natural protein fibers, such as wool and silk, can be dyed at normal pressure, have good dyeability and excellent texture and color, but have poor bulkiness and yarn strength and wash and wear properties. , Pleatability, dimensional stability, yellowing, insect repellent, antifungal property, etc. are inferior. For this reason, in order to make up for these performances lacking in protein fibers, mixed use with polyester fibers has been carried out.
However, since polyester fibers require high-temperature and high-pressure dyeing, the same color as protein fibers cannot be obtained when dyed under the same conditions as protein fibers. Dyeing at a high temperature of 130 to 135 ° C., which is the normal polyester fiber dyeing temperature, makes it easy to obtain the same color as the protein fiber, but the protein fiber is easily embrittled, and the physical properties such as strength and elongation are reduced. There is a problem that yellowing coloring occurs. In addition, when dyeing with a carrier agent under normal pressure, contamination by protein dyes increases with disperse dyes, and the working environment due to carrier odor is difficult to remove from the fibers and is difficult to remove the carrier. There is a problem such as lowering.

In the case of a fabric made of cellulose fiber, it has excellent water absorption and texture, but has problems in strength, bulkiness, dimensional stability, wash and wear, anti-wrinkle, tailoring, insect-proofing, and anti-fungal properties. . In order to solve these problems of cellulose fibers, weaving with polyester fibers is performed. Although direct dyes are often used for dyeing cellulose fibers, the use of reactive dyes has recently been increasing in order to increase fastness. However, the heat resistance of reactive dyes is usually 95 ° C or less, and the cross fabric of polyester fiber and cellulose fiber has a large difference in the dyeing temperature of each fiber. In addition, it is not possible to perform one-step one-bath dyeing excellent in operability.
Since polyurethane fibers have excellent stretch elasticity, they are mixed with polyester fibers and widely used in swimwear, sports knits, socks and the like. If a mixed product of polyester fiber and polyurethane fiber is dyed at a high temperature of 130 to 135 ° C., which is a normal polyester fiber dyeing temperature, there is a problem that the elastic elasticity, strength, and elongation of the polyurethane fiber are greatly reduced.

As described above, in fabrics made by knitting and knitting polyester fibers with wool and silk, knitting with cellulose fibers, knitting with polyurethane fibers, etc., high-temperature and high-pressure dyeing of polyester fibers can eliminate the advantages of wool, silk and cellulose fibers. The present situation is that the purpose of compounding has not been achieved. Of course, many studies have been reported over the last several decades to improve the dyeability of polyester fibers using disperse dyes, that is, the development of polyester fibers that can be dyed at lower temperatures.
Polyester fiber spinning methods can be roughly divided into the following three methods.
(1) A method in which spinning is performed at a winding speed of 1000 to 1500 m / min, and the undrawn yarn is drawn and heat treated 3 to 4 times as an undrawn yarn. (Normal method)
(2) A method of spinning at a winding speed of 4000 m / min or less to obtain so-called POY, and drawing and twisting the POY at 1.05 to 1.5 times. (Direct extension method)
(3) A method of performing high speed spinning at a winding speed of 5000 m / min or more. (High speed spinning method)

Considering from the spinning method, it is generally known that the fiber by the high speed spinning method in which spinning is performed at a winding speed of 5000 m / min or more has higher dyeability than the polyester fiber obtained by the usual method. Yes. However, as long as polyethylene terephthalate is used, a fiber exhibiting sufficient dyeability at 95 ° C. or lower cannot be obtained using a disperse dye.
Therefore, as a technique for improving the dyeability of polyester fiber disperse dyes, a method of modifying a raw material polymer, a method of improving a dyeing method and a post-treatment method, and the like have been studied.
As a method for modifying a raw material polymer, polyester fiber copolymerized with glycols such as tetramethylene glycol and 1,4-cyclohexanediol is disclosed in Patent Document 1, and 2,2-bis (4- (2-hydroethoxy) is disclosed. Polyester fibers in a high-speed spinning method copolymerized with)) phenyl) propane are disclosed in Patent Document 2, and these are known. However, the polyester fibers obtained by these methods have the problem that although the dyeability is improved, they are not dyeable at 95 ° C. and the color fastness is poor.

Further, a polyester / silk mixed yarn obtained by copolymerizing polyoxyalkylene glycol typified by polyoxyethylene glycol is disclosed in Patent Document 3 and known. In this method, in order to impart atmospheric pressure dyeability by homopolymerization of polyoxyethylene glycol, it is necessary to substantially copolymerize 6.0% by weight or more, and the heat resistance of the polymer is inferior. Expensive nitrogen drying is required in the process, and the yarn breakage during spinning usually increases compared to polyethylene terephthalate. In addition, although improvement of rough texture of the texture caused by high-temperature dyeing due to low-temperature dyeing, reduction of silk gloss, etc. are recognized, the dyeing fastness and weather fastness of the resulting fiber are not sufficient, and there is a synergistic effect obtained by polyester blending It was insufficient.
Patent Document 4 discloses a fiber produced by high-speed spinning of a polyester containing a metal sulfonate group. Although the improvement of dyeability by this fiber is recognized, even at the boiling temperature (98 ° C) condition with the disperse dye, it is possible to achieve a dye exhaustion rate equivalent to 130 ° C dyeing of polyethylene terephthalate fiber spun by the usual method. Not done.

As a method for improving the dyeing method and the post-treatment method, for example, carrier dyeing is known. However, since carrier dyeing uses high-boiling organic compounds such as phenol derivatives, aromatic halogen compounds, and biphenyl derivatives in the dye bath, there is a problem that waste liquid treatment and workability are significantly deteriorated. Further, Patent Document 5 and Patent Document 6 disclose a method in which a polyester fiber obtained by a high-speed spinning method is wet-heat treated at 180 to 300 ° C. to enhance the dyeing method.
However, although improvement in dyeability is recognized by wet heat treatment, there is a problem that the leveling property is poor and the advantage of the productivity of the high-speed spinning method is not utilized to reheat the fiber once obtained by the high-speed spinning method. Has a point.
As described above, at present, polyester fibers suitable for compounding with other materials having a soft texture with normal pressure dyeable polyester fibers have not yet been completed.

JP 58-120815 A JP 59-1000081 A Japanese Patent No. 2859875 Japanese Patent Publication No. 60-010126 JP 58-136825 A Japanese Examined Patent Publication No. 63-073650

  The object of the present invention is to solve the above problems by modifying polyethylene terephthalate, exhibiting dyeing properties far superior to conventional polyester fibers, and particularly excellent in fluctuations in fineness over a long period. Easy-dyeing polyester fiber that shows level dyeability and has a soft texture, making use of the strengths of each material and making up for the disadvantages by combining with other materials such as silk, wool, cellulose fiber, polyurethane fiber, etc. Is to provide.

As a result of diligent research, the present inventor has found that a polyester fiber having a single yarn decitex of 1.4 or less, obtained by copolymerizing polyethylene terephthalate with 3 to 6% by weight of polyethylene glycol having a molecular weight of 300 to 2000, having a molecular weight of 5000 m / min or more. As a result of finding that the fiber spun at the winding speed can solve the above-mentioned problems and further studying it, the present invention has been achieved.
That is, the first of the present invention is a polyester obtained by copolymerizing polyethylene terephthalate with 3 to 6% by weight of polyethylene glycol having a molecular weight of 300 to 2000, and 90% by weight or more is made of polyethylene terephthalate composed of ethylene terephthalate repeating units. It is an easily dyeable polyester fiber characterized by having a yarn decitex of 1.4 or less and satisfying the following requirements.
(A) The fineness fluctuation value U% is 1.0% or less, and the maximum value of the coefficient of variation CV in the period of 10 to 80 m 2 by the fineness fluctuation frequency analysis is 0.3% or less (however, the fineness fluctuation value U% The measurement is performed over a yarn length of 500 m).
(B) The temperature (Tmax) at which the mechanical loss tangent (tan δ) reaches the maximum at a measurement frequency of 110 Hz is 85 ° C. ≦ (Tmax) ≦ 105 ° C.
The second of the present invention is a polyester obtained by copolymerizing polyethylene terephthalate with 3 to 6% by weight of polyethylene glycol having a molecular weight of 300 to 2000, comprising 90% by weight or more of polyethylene terephthalate composed of ethylene terephthalate repeating units, and a single yarn decitex. Is produced at a winding speed of 5000 m / min or more, satisfying the following requirements (A) and (B) when producing a polyester fiber having a thickness of 1.4 or less: Is the method.
(A) The distance between the spinning holes is 8 mm or more and 30 mm or less. (B) The discharge linear velocity at the spinning hole outlet is 0.2 m / second or more and 1.0 m / second or less.

  Polyester fibers obtained by copolymerizing polyethylene terephthalate with 3 to 6% by weight of polyethylene glycol having a molecular weight of 300 to 2000 and having a single yarn decitex of 1.4 or less are spun at a winding speed of 5000 m / min or more. Thus, polyester fibers having normal pressure dyeability, extremely small variation in fineness, in particular, long-period fineness variation, excellent leveling property, and soft texture can be obtained. This fiber is a material that is very suitable for compounding with other materials, such as union with cellulose fiber, union with wool and silk, union with polyurethane fiber, and the like.

[Action]
In the first invention of the present invention, polyethylene glycol used as a copolymerization component causes an appropriate disturbance in the amorphous structure of the fiber and contributes to an improvement in dyeability.
Polyethylene glycol having a molecular weight of less than 300 is not preferable because the easy dyeing effect is insufficient and a copolymerization amount of 6% by weight or more is required to achieve atmospheric pressure dyeability, and the polymer color tone deteriorates. In addition, since polyethylene terephthalate is a polyethylene glycol having a molecular weight of less than 300 due to polymerization under vacuum, a part of the polyethylene terephthalate is scattered outside the product system and the polymer composition becomes unstable.
On the other hand, when the molecular weight of polyethylene glycol exceeds 2000, the ultrahigh molecular component increases with block copolymerization, and the decrease in dyeing fastness and light resistance becomes obvious, which is not preferable.
When the copolymerization amount of polyethylene glycol is less than 3% by weight, the dyeability at normal pressure is insufficient, and normal pressure dyeability cannot be obtained. On the other hand, when it exceeds 6% by weight, the dyeability at normal pressure is sufficient, but the polymer color tone deteriorates, and at the winding speed of 5000 m / min or more, yarn breakage and fluffing frequently occur and stable. Production becomes difficult. In particular, this problem is remarkable in the region where the fineness is thin. Furthermore, the filaments produced are not preferred because light fastness, dyeing fastness and the like deteriorate.

The easily dyeable polyester fiber according to the present invention uses a super-high speed spinning method, so it has a soft texture compared to the polyester fiber by the conventional method, and further crystallization is suppressed by copolymerizing polyethylene glycol, It has a soft texture, and the softness can be further increased by reducing the fineness. When combining with natural materials such as silk and wool, it is necessary to make the single yarn decitex on the polyester fiber side finer so as not to impair the texture of each material. Also in the easily dyeable polyester fiber in the present invention, when the single yarn decitex exceeds 1.4, the unique texture of other materials is impaired and the hard texture of the polyester fiber is emphasized. The single yarn decitex is preferably 1.4 or less, and more preferably 1.2 or less.
The easily dyeable modified polyester fiber of the present invention needs to have a loss tangent peak temperature (hereinafter referred to as Tmax) determined from dynamic viscoelasticity measurement of 85 to 105 ° C. This is because the dyeability required by the present invention can be secured within this range. Since Tmax corresponds to the mobility of molecules in the amorphous part, it can be said that the smaller the value, the easier the dye enters the amorphous part, that is, the higher the dyeability.

When the Tmax exceeds 105 ° C., the dyeable modified polyester fiber of the present invention is not preferable because the effect of improving dyeability is small and dyeing at a higher temperature is required. However, if Tmax is too low, problems such as a decrease in mechanical properties and heat resistance appear. Practically, the temperature is 85 to 105 ° C, and particularly preferably 90 to 100 ° C.
Although not as important as Tmax, the loss tangent value at Tmax (hereinafter referred to as tan δmax) is preferably about 0.13 to 0.22. The loss tangent value corresponds to the amorphous amount, and if it is out of this range, the dyeability and fastness may deteriorate.
In general, when the fabric is made fine by reducing the fineness of the fiber, the dyeability of the fabric tends to become lighter.In the present invention, due to the effect of improving the dyeability by high-speed spinning and copolymerization of polyethylene glycol, Even if the fineness is reduced, sufficient dyeability can be obtained.

[Production method]
Next, using polyethylene terephthalate, which is a polyester obtained by copolymerizing 3 to 6% by weight of polyethylene glycol having a molecular weight of 300 to 2,000 with polyethylene terephthalate according to the second invention, 90% by weight or more is composed of ethylene terephthalate repeating units,
(A) Spindle core distance is 8 mm or more and 30 mm or less. (B) A spinneret having a feature that discharge linear velocity at the spinning hole outlet is 0.2 m / sec or more and 1.0 m / sec or less is used. The method for producing a polyester fiber according to claim 1, wherein spinning is performed at a take-up speed of 5000 m / min or more.
In the polyester of the present invention, at least 90% of the structural unit is ethylene terephthalate, and in addition to the polyethylene glycol component, other components of 5 mol% or less may be copolymerized. For example, a polymer obtained by polymerizing a chain branching agent such as pentaerythritol, trimethylolpropane, trimellitic acid or boric acid in a small proportion may be used.
In addition to the above copolymerization components, normal matter exchange catalysts, polymerization catalysts, phosphorus compounds, matting agents such as titanium dioxide, coloring inhibitors, oxidative decomposition inhibitors, antifoaming agents, fluorescent light increasing agents, pigments Etc. may be contained as required.

A well-known method can be employ | adopted for the polymerization method of the polymer which comprises the easily dyeable polyester fiber of this invention. That is, polyethylene glycol may be reacted with terephthalic acid, ethylene glycol, or the like, or may be reacted after transesterification of dimethyl terephthalate and ethylene glycol, and at any stage where the polyester polymerization reaction is completed. It may be added. In addition, any of the batch polymerization method and the continuous polymerization method that are currently being industrially produced can be applied.
The easily dyeable polyester fiber of the present invention can be obtained by a high speed spinning method having a winding speed of 5000 m / min or more. On the other hand, sufficient dyeability cannot be obtained even if the copolymerized polyester is made into a fiber using a normal method or a straight-roll method. This is due to the fact that the orientation of the amorphous part of the fiber obtained by high speed spinning is much smaller than that of the fiber obtained by the ordinary method or the straight-drawing method. In particular, since the polymer used in the present invention has polyethylene glycol having a moderately long molecular chain in the amorphous part, the orientation of the amorphous part is further reduced and the dyeability is improved. For this reason, the obtained copolyester fiber of the present invention has a soft texture and is an epoch-making fiber excellent in mechanical properties.

Conventionally, when a fiber having a fine fineness is produced by using a high-speed spinning method, it has been apparent that the spinning process is not stabilized and dyed spots due to fineness spots in the longitudinal direction of the fiber become apparent. In particular, this tendency was remarkable in a fine fineness region having a fiber fineness of 1.4 dtex or less. In order to avoid this situation, the present inventors have conducted intensive research. As a result, in the high-speed spinning method with a single yarn decitex of 1.4 or less and 5000 m / min or more, as shown in FIG. 1 and FIG. It has been found that by using a spinning nozzle having a center-to-core distance of 8 mm or more and 30 mm or less, spinning is stabilized, fineness variation is reduced, and dyeing spots are avoided.
When the distance between the spinning cores is small and less than 8 mm, U% indicating the fineness variation value in the fiber longitudinal direction becomes 1.0% or more, and the variation of the fineness becomes large. Further, when the fluctuation is subjected to frequency analysis, the fluctuation coefficient of 10 to 50 m period by the fineness fluctuation frequency analysis becomes large as shown in FIG. 4, and the maximum CV value exceeds 0.3%, 0.5% When the level dyeability is evaluated with a single knitted fabric, streaky dyed spots become obvious and high-quality easily-dyeable polyester cannot be obtained. Furthermore, when the distance between the cores is less than 8 mm, the influence of the accompanying air flow accompanying necking stretching, which is peculiar to ultra high speed spinning, is great, and fineness becomes uneven due to yarn swinging.

U% and its frequency analysis chart in the present invention are as shown in FIG. 5, the fluctuation of the fiber fineness in the longitudinal direction is very small, there is no specific frequency fluctuation accompanying the longitudinal distance of the fiber, and the CV value is 0. It can be said that the fineness is very stable and uniform in the longitudinal direction.
In order to make the fineness spots smaller and more stable, the distance between the spinning cores is preferably 10 mm or more. In addition, the spin hole arrangement in the case of using a spinning equipment attached with a cooling cylinder composed of circumferential cooling at a high speed spinning of 5000 m / min or more is preferably a single circle arrangement, but when the center distance is less than 8 mm, It is necessary to arrange the spinning holes in a multi-circular circle, and the inter-spindle core distance located in the inner layer at this time is 10 mm or more, preferably 12 mm or more because the accompanying airflow of the outer layer spinning hole is added. It is preferable.

On the other hand, when the distance between the cores exceeds 30 mm, there is no improvement effect on U% and quality, and the spinneret size is huge, which is not practical for industrial production.
On the other hand, the cause of frequent yarn breakage and fluff in high-speed spinning with a single yarn decitex of 1.4 or less is not clear, but in the present invention, polyethylene glycol is used to impart easy dyeability. Because it is copolymerized and heat resistance is usually inferior to polyethylene terephthalate, viscosity spots, catalysts, and aggregates of additives in the polymerization process and spinning process are likely to occur, and the single yarn decitex is 1.4 or less and 5000 m In the case of high-speed spinning at a speed of at least / min, it is likely to be affected by fluctuations in viscosity, agglomerates of catalysts, additives, and the like, and it is considered that yarn breakage and fluffing became obvious.
In order to prevent yarn breakage and fluff, it is necessary to pay close attention to the polymer polymerization stage and spinning process to prevent abnormal polymer retention as much as possible. However, it is difficult to completely eliminate the abnormal retention part. Therefore, as a result of intensive studies to avoid the influence of viscosity fluctuations and aggregates of catalyst and additive, yarn breakage and fluff can be controlled by setting the discharge linear velocity from the polymer spinning hole to 20 cm / second or more and 100 cm / second or less. Has been found to be resolved.

When the spinning discharge linear velocity is less than 20 cm / second, yarn breakage and fluff are likely to occur frequently. Preferably, the spinning discharge linear velocity is 40 cm / second or more. When the spinning hole discharge linear velocity exceeds 100 cm / sec, melt fracture tends to occur, which may cause unstable spinning and impossible spinning. In addition, when the spinning hole discharge linear velocity is less than 20 cm / second, the fluctuation CV value of a long period of 30 to 80 m by the fineness fluctuation frequency analysis becomes a large value exceeding 0.3%, and the leveling property evaluation by the one-neck knitted fabric is evaluated. When this is done, band-like dyeing spots become obvious, and a high-quality, high-quality easily-dyeable polyester cannot be obtained.
On the other hand, it is possible to apply the present invention in the sense of improving the spinnability even in a normal polyester not copolymerized with polyethylene glycol, but in a normal polyester not copolymerized with polyethylene glycol, the spinning discharge linear velocity is 40 cm. / Sec or more, melt fracture is likely to occur and it cannot be practically applied.

The easily dyeable polyester fiber of the present invention can be produced using, for example, a spinning device shown in FIG. As the focusing guide comprising the oiling nozzle used in the present invention, the winding device, and other devices necessary for melt spinning, known devices may be used. The finishing oil used in the present invention may be either an emulsion type or a straight type, and the components thereof may be known.
The winding speed at the time of producing an easily dyed modified polyester fiber having sufficient practical characteristics by only the melt spinning process without passing through the stretching process of the present invention is required to be 5000 m / min or more, and 5000 m A yarn obtained at a winding speed of less than / min is likely to be stretched in the weaving / knitting process, and frequently causes a stain or a deterioration in the quality of the fabric, which is a practical obstacle.
The easily dyeable polyester fiber of the present invention thus obtained exhibits excellent dyeability, in particular, very small variation in fineness in a long period of 10 to 80 m in fiber length, excellent uniform dyeability, and fastness. It has excellent water absorbency and soft texture, and is useful in product fields woven with cellulose fibers, knitted with wool and polyurethane fibers with low heat resistance, and foundation, lingerie and other innerwear, sportswear, and outerwear Any of these can be used.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In addition, the measuring method of the characteristic value used by this invention is shown below.
(1) Polymer reduced viscosity (ηsp / c)
Using ortho-chlorophenol as a solvent, the measurement was performed at a polymer concentration of 1.0% and 35 ° C.
(2) Strength / Elongation Using a tensile tester manufactured by Orientec Co., Ltd., measurement is performed under the conditions of a yarn length of 20 cm and a tensile speed of 20 cm / min.

(3) Fineness Fluctuation Value U% / U% Waveform Height Difference A fineness fluctuation value chart (graph; Diagram Mass) is obtained at the same time as U% is measured by the following method.
・ Evening instrument (manufactured by Twelvegar Worcester; Wooster Tester UT-4)
・ Measurement conditions Measurement method Normal Yarn speed 100m / min Disc tension strength (Tension force) 10%
Twist S: 10000 times / min
Measuring thread length 500m
Scale ± 10%
・ Fineness fluctuation value U%
The fluctuation chart and displayed fluctuation values were read directly.
・ CV value (%) by fineness variation frequency analysis
Using the fineness variation frequency analysis software attached to the evening tester, measure the yarn length of 500 m under the above conditions, and read the CV value for each frequency that is the yarn length unit. The maximum value in the frequency range of 30 to 80 m is the CV value (%).

(4) Loss tangent Using a Levivibron manufactured by Orientec, the sample weight is about 0.1 mg, the measurement frequency is 110 Hz, the heating rate is 5 ° C./minute, and the measurement is performed in dry air. ), And dynamic viscoelasticity (E ′). From the result, a tan δ-temperature curve is obtained, and a temperature (° C.) at which tan δ exhibits a maximum value on this curve and a maximum value tan δ max of tan δ at that time are obtained.
(5) Exhaust rate, deep chromaticity (K / S) measurement: Evaluation of dyeability The sample is a knitted fabric with yarn and a hot water containing 2 g / liter of score roll 400, and refined at 70 ° C. for 20 minutes. Then, it was dried with a tumbler dryer, and then heat-set at 180 ° C. for 30 seconds using a pin tenter was used.
As a dye, Sumikaron Blue / S-3RF (trade name, manufactured by Sumitomo Chemical Co., Ltd.) is used in an amount of 5% by weight based on the fabric, and as a dispersant, Nikka Sun Salt 7000 (manufactured by Nikka Chemical Co., Ltd., trade name). ) 0.5 g / liter, acetic acid 0.25 ml / liter, sodium acetate 1.0 g / liter was added to adjust the pH to 5 to obtain a dyeing solution. The exhaustion rate was obtained by substituting the absorbance of the dye stock solution with A and the absorbance a of the dyed solution after dyeing from a spectrophotometer and substituting it into the following equation. As the absorbance, a value at 580 nm, which is the maximum absorption wavelength of the dye, was adopted.
Exhaust rate = [(A-a) / A] x 100 (%)
The deep chromaticity was evaluated using K / S. This value was determined from the Kubelka-Munk equation shown below by measuring the spectral reflectance R of the dyed sample fabric. A larger value indicates that the deep color effect is greater, that is, the color is well developed. The value at 580 nm, which is the maximum absorption wavelength of the dye, was adopted.
Deep chromaticity: K / S = (1-R) ² / 2R

(6) Leveling evaluation Scouring: Create a tubular knitted fabric and score roll (non-ionic surfactant manufactured by Kao Corporation)
Scouring at 2g / 70 ° C x 15 minutes Dyeing: Foron Navy Blue SGL
3% owf, 100 ° C. × 30 minutes Evaluation: Three-level evaluation was performed by three veteran judges, and the following determinations were made.
○: 8 or more and good leveling.
Δ: 7 to 6 slightly bad
X: Bad or bad at 6 or less.
(7) Evaluation of spinnability The number of yarn breakage when spinning with one spindle for 24 hours was evaluated as follows.
○: The number of thread breaks is 1 or less.
Δ: The thread breakage is 1 to 3 times.
X: When the number of thread breakage exceeds 3 times.

(8) Texture evaluation The fabric was relatively evaluated according to the following criteria based on the feel of the inspector (30 persons).
A: Soft, supple feeling is very good and close to nylon.
○: Soft and supple feeling is good.
Δ: Soft and supple feeling is slightly inferior.
×: Soft and supple.
(9) Degree of coloration of polyurethane fibers in the dyed product Polyurethane fibers are extracted from the fabric, and the degree of coloration is evaluated using a spectrocolorimeter (manufactured by Kollmorgen; model Macbeth MS-2020) in accordance with JIS-Z-8730. did. The coloring degree D indicates a difference in coloring degree between polyurethane fibers before dyeing and after dyeing finish, and was determined by the following formula in the Lab color system.
D = (ΔL ² + Δa ² + Δb ² ) ^1/2

[Examples 1-4, Comparative Examples 1-4]
100 parts of dimethyl terephthalate (hereinafter referred to as “DMT”), 76 parts of ethylene glycol and 0.04 part of manganese acetate tetrahydrate salt as a transesterification catalyst were charged and heated from 150 ° C. to 240 ° C. for 3 hours. The ester exchange reaction was carried out while distilling methanol. Next, 0.04 part of trimethyl phosphate as a stabilizer, 0.05 part of antimony trioxide as a polymerization catalyst, and 0.4 part of titanium dioxide as a matting agent were added, and then polyethylene having a molecular weight and an addition amount shown in Table 1 were added. Glycol and Irganox 245 (manufactured by Ciba Geigy) as a heat stabilizer are added to the polyethylene glycol to 3% and mixed and added. Thereafter, a polycondensation reaction was carried out at normal pressure over 30 minutes and transferred to a polymerization tank. After completion of the transfer, the pressure was gradually reduced and a polycondensation reaction was performed at a vacuum degree of 0.5 Torr and 275 ° C. to obtain a modified polyester having ηsp / c = 0.73.
Using these polymers, a spinning circle of 280 ° C. was wound at a spinning temperature of 280 ° C. using a two-circular circularly arranged nozzle having 36 spinning holes (24 in the outer layer and 12 in the inner layer) drilled to a spinning diameter of 0.17φ. High-speed spinning was performed at a take-up speed of 5800 m / min to obtain 44 dtex / 36 filament fibers. Table 1 shows the evaluation results such as dyeability, water absorption, texture, and spinnability of the obtained easily dyeable polyester fiber.

The dyeability of the readily dyeable polyester fiber of the present invention with respect to the disperse dye can be evaluated by comparing the dyeability of a polyethylene terephthalate fiber (Tmax = 136 ° C) spun by a conventional method at 130 ° C for 60 minutes. The exhaust rate of the polyethylene terephthalate fiber spun by the usual method with respect to the disperse dye was 94%, and K / S was 24.
Polyethylene terephthalate fibers spun by the usual method, in which the easily dyed modified polyester fibers obtained in Examples 1 to 4 have an exhaustion rate of disperse dyes in the range of 80 to 95% at 60C for 60 minutes. However, the K / S of the deep color showed almost the same value, and it was recognized that the color was visually equivalent.
About Comparative Examples 1-4, dye exhaustion rate or spinnability, and the texture fell.
Contamination and transferability of the dye to the polyurethane fiber were evaluated by the following methods.
Using the yarn obtained above and 33 dtex polyether polyurethane fiber (Asahi Kasei Fibers Co., Ltd., trade name: Leuka SC), a 6-course satin net knitted fabric (course density of 171 loops) under normal knitting conditions /2.54 cm, well density 41 loop number / 2.54 cm). The mixing ratio of polyurethane fibers in this polyurethane fiber mixed knitted fabric was 21%.

This mixed knitted fabric was scoured and relaxed while changing the temperature to 40 ° C., 60 ° C., and 90 ° C. on the spread, and then preset at 190 ° C. and dyed under the following dyeing conditions.
Dye: C.I. I. Disperse Blue 79.1 4% omf
(Benzene monoazo disperse dye)
Dispersing leveling agent: Nikka Sun Salt RM-340 (manufactured by Nikka Chemical Co., Ltd.)
0.5 g / liter Acetic acid: 0.5 cc / liter Sodium acetate: 1 g / liter SR-1801M Conch 4% omf
Bath ratio: 1:15
Dyeing temperature, time: 98 ° C, 30 minutes

After the dyeing is completed, the dyeing residual liquid is discharged from the dyeing machine, water is added to the dyeing machine, the temperature is raised to 70 ° C., and the following chemicals are added to this to adjust the reducing cleaning bath with the following concentration, and the dyed product The sample was subjected to reduction cleaning at 70 ° C. for 10 minutes.
Thiourea dioxide: 2 g / liter Caustic soda: 1 g / liter Bisnol UP-10 (manufactured by Yushi Co., Ltd.): 0.5 g / liter Bath ratio: 1:20
After this reduction cleaning, the residual liquid was discharged, and the dyed product was sufficiently rinsed with warm water and water, and then finished with a dry heat set at 150 ° C. for 30 seconds. Table 1 shows the evaluation results of the degree of coloration of the polyurethane fibers in the finished dyeing. As a result, in Examples 1 to 4, there was almost no stain or transferability of the dye to the polyurethane fiber, and it was extremely small.

[Examples 5 and 6, Comparative Examples 5 and 6]
The number of holes in the outer layer and the inner layer was changed with the same polymer and spinning equipment and conditions as in Example 1, and 44 dtex / 36 filament (single yarn 1.2 dtex) was easily obtained using a spinning nozzle with a different distance between the spinning cores. A dyeable polyester fiber was obtained. The obtained easily dyeable polyester fiber was evaluated in the same manner as in Example 1. In Examples 5 and 6, the fineness variation CV value is 0.25, which is within the scope of the present invention. However, as in Comparative Examples 5 and 6, the center distance of the spinning hole is outside the scope of the present invention. And the fineness variation CV value was as large as 0.4 to 0.6, and fineness spots became large.

[Examples 7 and 8, Comparative Example 7]
Using the same polymer and spinning equipment as in Example 1, the diameter of the spinning hole was changed to obtain 44 dtex / 36 filaments of easily-dyeable polyester fiber. The obtained easily dyeable polyester fiber was evaluated in the same manner as in Example 1.
[Comparative Example 8]
Using the same polymer and spinning equipment as in Example 1 and changing the number of spinning holes, 44 dtex / 24 (single yarn 1.8 dtex) filament readily dyeable polyester fibers were obtained. The obtained easily dyeable polyester fiber was evaluated in the same manner as in Example 1. As a result, since the fineness was 1.8 dex, which was larger than the present invention, the flexibility and texture were lowered.
[Comparative Example 9]
Using the same polymer as in Example 1, spinning at a winding speed of 1500 m / min, drawing 3 times through a hot roll at 80 ° C. and a hot plate at 135 ° C., a 44 dtex / 36 filament polyester fiber Got. This fiber had a Tmax of 110 ° C. and a dye exhaustion rate as low as 38%.

The cross-sectional schematic diagram of the spinneret used by this invention is shown. A schematic plan view of a spinning nozzle used in the present invention is shown. The spinning production process of the easily dyeable polyester fiber of this invention is shown. U% chart by conventional spinning nozzle and frequency analysis chart by evening tester. The frequency analysis chart by U% by this invention spinneret and an evenness tester.

Claims (2)

Polyester obtained by copolymerizing polyethylene terephthalate with 3 to 6% by weight of polyethylene glycol having a molecular weight of 300 to 2000, 90% by weight or more is made of polyethylene terephthalate composed of ethylene terephthalate repeating units, and the single yarn decitex is 1.4 or less. An easily dyeable polyester fiber characterized by satisfying the following requirements (a) and (b).
(A) The fineness fluctuation value U% is 1.0% or less, and the maximum value of the coefficient of variation CV in the period of 10 to 80 m 2 by the fineness fluctuation frequency analysis is 0.3% or less (however, the fineness fluctuation value U% The measurement is performed over a yarn length of 500 m).
(B) The temperature (Tmax) at which the mechanical loss tangent (tan δ) reaches a maximum at a measurement frequency of 110 Hz is in the range of 85 ° C. ≦ (Tmax) ≦ 105 ° C. 2. The polyester according to claim 1, wherein when producing a polyester fiber having a single yarn decitex of 1.4 or less, the following requirements (A) and (B) are satisfied, and spinning is performed at a winding speed of 5000 m / min or more. A method for producing fibers.
(A) The distance between the spinning holes is 8 mm or more and 30 mm or less. (B) The discharge linear velocity at the spinning hole outlet is 0.2 m / second or more and 1.0 m / second or less.

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