JPH1193021A - Sheath-core polyester yarn - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester based yarn darkly dyeable with a disperse dye, having a strength and a proper modulus of elasticity, excellent in heat setting properties and fastness to dry cleaning, suitable for combination with a yarn poor in heat stability or use with a dye having low heat resistance such as a reaction dye, excellent in handleability in weaving and knitting, capable of providing a fabric having a soft handle. SOLUTION: This sheath-core polyester-based yarn comprises a polyester consisting of a sheath part composed of terephthalic acid as an acid component and trimethylene glycol as a glycol component and a core part composed of terephthalic acid as an acid component and ethylene glycol as a glycol component and has the ratio of the diameter of the core part to the diameter of the yarn of 40-90%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyester fiber having a sheath-core structure. More specifically, it has the characteristics of both nylon fiber and polyester fiber, has low-temperature dyeability, heat-setting properties, and fastness. The present invention relates to a sheath-core polyester fiber which is excellent in handleability and can obtain a soft-textured fabric.

[0002]

2. Description of the Related Art Nylon fibers are widely used in the field of clothing and materials due to their low elastic modulus, high elastic recovery and low-temperature dyeability. In the field of clothing, it is widely used in the field of women's innerwear and pantyhose, where softness is strongly required by utilizing the characteristic of low elastic modulus, for example, by mixing with stretch fibers represented by polyurethane fibers.
In the field of materials, nylon fibers are used for carpets, fishing nets, canvas, etc. because of their excellent elastic recovery and resistance to bending and friction.

[0003] Further, with respect to the problem of post-processing properties, since nylon fibers are dyeable at low temperatures, for example, when nylon fibers and cellulose fibers are mixed, heat resistance is low for dyeing the cellulose fibers. Using a reactive dye and combining it with an acid dye, one-step one-bath dyeing at normal pressure can be performed. Also, wool, silk, polyurethane fiber,
At a dyeing temperature exceeding 110 ° C. such as acetate fiber, when mixed with a fiber which is susceptible to thermal deterioration, it has excellent processing characteristics that dyeing is possible without damaging the fiber.

[0004] As described above, despite the fact that nylon fibers have a large market among synthetic fibers, taking advantage of the characteristics of low elastic modulus, high elastic recovery, and low-temperature dyeability, the following critical fibers are used. It also has disadvantages. In other words, nylon fibers have poor heat setting properties.For example, when knitted fabrics such as tricots and Russell mixed with stretch fibers are used for a long time,
Since the tissue shift of laughing easily occurs, the fabric has poor dimensional stability and form stability. In addition, there is a problem that yellowing is likely to occur when used for a long time or exposed to excessive sunlight due to poor light resistance. Furthermore, handling during post-processing such as woven knitting is difficult because the elastic modulus is too low.

On the other hand, polyester fibers typified by polyethylene terephthalate fibers are excellent in heat setting property, weather resistance, and handling properties of fibers, but have a high elastic modulus, resulting in a hard feeling or elastic recovery. It has the opposite performance to nylon fibers, such as poor quality and necessity of dyeing at high temperature. It has low temperature dyeability, heat setting property, robustness, high strength, moderate elasticity, and excellent handleability during weaving knitting, which has the characteristics of both nylon fiber and polyester fiber. If it is possible to produce fibers having a good texture, the problems of the physical properties of nylon fibers and polyester fibers can be solved, and a fabric having a soft feel and excellent heat setting properties can be provided, but such fibers have been known so far. Absent.

[0006] Fibers having good dyeing properties for disperse dyes, low elastic modulus and excellent elastic recovery properties include, for example,
The polytrimethylene terephthalate fiber disclosed in JP-A-52-5320 is mentioned. The fiber disclosed herein has a low elastic modulus comparable to nylon and excellent elastic recovery, but has a low strength of about 3 g / d, and is subjected to a slight tension when handling the fiber for post-processing. They may be cut or only weakly woven fabrics may be obtained. In addition, since the elastic modulus is too low, the yarn is easily stretched when tension is applied thereto during woven knitting, so that it is difficult to handle. Further, after the woven knitting, the tension is released and the yarn shrinks, so that the obtained fabric is obtained. The density of the woven or knitted fabric is too high,
It has a hard texture and shrinkage spots, resulting in wrinkles.

Polybutylene terephthalate fibers also have good dyeing properties, relatively high strength, low elastic modulus, and excellent elastic recovery, and have already been put to practical use in some fields replacing nylon fibers. ing. However,
The heat setting property is very poor due to the low glass transition point, and the dyeability is good, but the fastness to dry cleaning is poor. Further, since the elastic modulus is too low, the same problem as that of polytrimethylene terephthalate occurs at the time of knitting.

As a method for improving the dyeability of a polyester fiber composed of polyethylene terephthalate to a disperse dye and providing a soft feeling, a method of copolymerizing polyethylene terephthalate with polyoxyethylene glycol or adipic acid has already been known. (For example,
JP-A-3-40880, JP-A-3-174076
JP, JP-A-4-41732, JP-A-3-85
111, JP-A-3-235536).

However, although the dyeing properties are improved by these methods, the elastic modulus is not so different from that of polyethylene terephthalate, and a soft cloth cannot be obtained. Furthermore, light fastness and dry cleaning fastness are low, spinnability is not sufficient, yield is reduced, and fine denier is difficult, and the application is extremely limited. Further, as a method for softly improving the texture of such a fabric, an alkali weight reduction treatment for partially decomposing and dissolving the fibers with an aqueous alkali solution after fabricating the fabric is also performed. However, not only sufficient softness cannot be obtained by the alkali weight reduction treatment, but also the number of steps increases, and new equipment is required for processing waste liquid generated during the alkali weight reduction treatment, which increases costs.

[0010] As described above, in the range of the known art, it has low-temperature dyeability, heat-setting property, and fastness having both characteristics of nylon fiber and polyester fiber, and has high strength and moderate elastic modulus. A fiber having excellent handleability at the time of weaving knitting is not known.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide low-temperature dyeability, heat-setting properties, and fastness, which have the characteristics of both nylon fibers and polyester fibers, as well as high strength and moderate elasticity. It is an object of the present invention to provide a polyester fiber which is excellent in handleability at the time of weaving and knitting and has a soft texture.

More specifically, 110 to the disperse dye
C. or lower, can be dyed at a temperature of 3.5 g / d or more, has an elastic modulus of 40 to 70 g / d, has good heat setting properties, has excellent dry-cleaning fastness and light fastness, and is suitable for woven knitting and the like. An object of the present invention is to provide a polyester fiber which is excellent in handleability in post-processing and is useful for obtaining a fabric having a soft texture.

[0013]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a limited type of polymer is used in a sheath-core structure polyester fiber at a certain ratio, and the fiberization is carried out by a certain method. By doing so, a fiber having a specific structure can be obtained, and the possibility of solving the above-mentioned problem has been found. As a result of further study, the present invention has been reached.

That is, the present invention provides a polyester fiber comprising a sheath and a core, wherein the sheath comprises a polyester polymer comprising terephthalic acid as an acid component and trimethylene glycol as a glycol component, and the core comprises terephthalic acid. A sheath-core polyester fiber comprising an acid component and a polyester polymer containing ethylene glycol as a glycol component, wherein the ratio of the core diameter to the fiber diameter is 40 to 90%.

In the sheath-core polyester fiber of the present invention, the polymer constituting the sheath portion is a polyester containing terephthalic acid as an acid component and trimethylene glycol as a glycol component. In addition, the core has terephthalic acid as an acid component,
Polyester containing ethylene glycol as a glycol component. The sheath-core polyester fiber of the present invention, if necessary, in any polymer of the sheath portion and the core portion, within a range that does not impair the effects of the present invention, preferably within 10% by weight, more preferably within 5% by weight. , Isophthalic acid,
Acid components such as succinic acid, adipic acid and 2,6-naphthalenedicarboxylic acid, glycol components such as 1,4-butanediol and 1,6-hexanediol, ε-caprolactone, and 4-hydroxybenzoic acid are copolymerized. May be.

However, in this case, it is preferable that the copolymer component is such that the deterioration of the fastness does not occur. Further, if necessary, various additives, for example, a matting agent, a heat stabilizer, an antifoaming agent, a tinting agent, a flame retardant, an antistatic agent, an antioxidant,
An ultraviolet absorber, an infrared absorber, a crystal nucleating agent, a fluorescent whitening agent and the like may be copolymerized or mixed as necessary.

In the present invention, trimethylene glycol may be any of 1,3-propanediol, 1,2-propanediol, 1,1-propanediol, 2,2-propanediol, and a mixture thereof. 1,3-propanediol is particularly preferred from the viewpoints of elastic recovery, heat setting properties, and thermal stability. The polyester polymer of the sheath and the core constituting the sheath-core polyester fiber of the present invention can be polymerized by a known method. For example, the polymer used for the sheath portion is subjected to a transesterification reaction of terephthalic acid or a lower alcohol ester of terephthalic acid with an excess of 1,3-propanediol in the presence of a catalyst such as tetrabutyl titanate. Add a catalyst such as tetrabutyl titanate,
It can be obtained by performing a polycondensation reaction at 240 to 280 ° C. under a vacuum of 0.5 torr or less.

The polyester polymer used in the present invention is:
The molecular weight can be defined by the limiting viscosity. The intrinsic viscosity [η] of the polyester polymer used for the core is 0.5.
5 to 2, more preferably 0.55 to 1.5,
Particularly preferably, it is 0.6 to 1.2. The intrinsic viscosity is 0.
If it is less than 5, the strength and elongation of the obtained fiber will be low, and it will be difficult to obtain the high-strength fiber aimed at by the present invention, and the spinning property will be unstable because the melt viscosity of the polymer is too low. Becomes On the other hand, when the intrinsic viscosity is more than 2.0, the melt viscosity is too high, so that the light weight cannot be smoothly reduced by the gear pump, and the spinnability deteriorates due to poor discharge or the like.

On the other hand, the intrinsic viscosity [η] of the polyester polymer used for the sheath is preferably 0.4 to 1.5, more preferably 0.45 to 1.3, and particularly preferably 0.5 to 1.3.
1.2. If the intrinsic viscosity is less than 0.4, the strength of the obtained fiber is low, the elongation is low, and not only is it difficult to obtain the high-strength fiber for the purpose of the present invention, but the melt viscosity of the polymer is too low, The spinnability becomes unstable. On the other hand, when the intrinsic viscosity exceeds 1.5, orientation tends to occur easily during spinning, and the dyeing property is reduced. Also, the melt viscosity is too high, so that the light weight cannot be smoothly performed by the gear pump. Poor or uneven sheath-core structure may result. The intrinsic viscosity difference between the polymer used for the sheath and the polymer used for the core is preferably 0.5 or less, more preferably 0.4 or less. If the intrinsic viscosity difference between the polymer used for the sheath and the polymer used for the core exceeds 0.4, a uniform sheath-core structure will not be obtained during extrusion.

In the present invention, the ratio of the diameter of the core portion to the diameter of the fiber is such that the low-temperature dyeing and high strength which are the object of the present invention
It is extremely important to obtain a fiber having an appropriate elastic modulus. The ratio of the core diameter to the fiber diameter needs to be 40 to 90%, preferably 50 to 80%, and more preferably 60 to 70%. If the ratio of the diameter of the core to the diameter of the fiber is less than 40%, not only the fiber having the high strength intended for the present invention cannot be obtained, but also a fiber having a uniform sheath-core structure cannot be obtained. Uneven dyeing and uneven fiber diameter occur. The ratio is 90%
Exceeds 110 using the disperse dye which is the object of the present invention.
If the temperature is lower than ℃, it becomes impossible to dye to a deep color.

Further, the sheath-core polyester fiber of the present invention comprises:
The fiber density and the birefringence (Δn) of the sheath polymer are preferably specific values. The density and birefringence are not only the ratio of the sheath portion and the core portion, but also values that are indicators of the degree of crystallinity and orientation of the fiber, and have a strong influence on the strength and dyeability of the fiber. Fiber density is 1.33 to 1.40 g / c
m ³ is preferred, and more preferably 1.34 to 1.39 g.
/ Cm ³ , particularly preferably 1.35 to 1.38 g / cm ³
It is. The density is less than 1.33 g / cm ^{3 when} the ratio of the polymer in the sheath is too large, and both the sheath and the core are not sufficiently crystallized. Cannot be obtained, or the fastness to dry cleaning of a dyed product may be reduced. In addition, the density of the fiber, the sheath polymer,
Considering the density of the core polymer, the ratio does not exceed 1.40 g / cm ³ within the range of the ratio of the core of the present invention.

On the other hand, the sheath polymer has a birefringence of 0.01
To 0.07, more preferably 0.02 to 0.07.
06. When the birefringence of the sheath polymer is less than 0.01, the degree of orientation of the sheath polymer is too low and the sheath polymer becomes brittle, and when the fiber is bent, a scratch is generated. On the other hand, if it is 0.06 or more, the degree of orientation of the sheath polymer is too high, and it is difficult to dye to a deep color at 110 ° C. using a disperse dye, which is an object of the present invention. The relatively low degree of orientation of the sheath polymer can be achieved by arranging a polymer having a high elongation modulus as in the present invention on the core, so that a tension is applied to the polymer of the sheath having a low elongation modulus during spinning. Is less likely to occur, and the orientation of the polymer can be suppressed.

The sheath-core polyester fiber of the present invention preferably has a strength of 3.5 g / d or more, more preferably 4 g / d or more. When the strength is 3.5 g / d or more, it is usually possible to perform the same knitting method and post-processing as the nylon fiber or polyester fiber. Also,
The elastic modulus is preferably from 40 to 80 g / d, more preferably from 50 to 70 g / d. The elastic modulus is 40 g /
If it is less than d, the yarn is easily stretched when tension is applied to the yarn during weaving and knitting, and it is difficult to handle. Further, after weaving and knitting, the tension is released and the yarn shrinks. It becomes too high, has a hard texture, and has many wrinkles due to shrinkage spots. On the other hand, the elastic modulus is 8
If it exceeds 0 g / d, it will be difficult to obtain a soft-textured cloth which is the object of the present invention. Elastic modulus is 40
When the content is within the range of 80 g / d, it is possible to obtain a fiber, which is an object of the present invention and has good handleability during knitting and can obtain a fabric having a soft texture.

The sheath-core polyester fiber of the present invention can be obtained by the following method. When spinning from the spout pack at the time of spinning, two kinds of polyester polymers, a sheath polymer and a core polymer, are used, so it is necessary to select a spout pack suitable for making a desired cross-sectional structure. These can use a well-known technique.
Hereinafter, an example of a spinning pack is shown with a schematic diagram.

For example, a spinning pack as shown in FIG. 1 may be used. In FIG. 1, after the sheath polymer has passed through the filtration section from A and the core polymer has passed through the filtration section from B, it is introduced into the capillary 2 through the horizontal flow path 1 and discharged from the spinneret 3 to be discharged and formed as a filament group. By doing so, the sheath-core structure aimed at by the present invention can be obtained. In the production of the sheath-core polyester fiber of the present invention, the temperature at which the polymer is extruded from the spinneret is preferably from 280 to 330 ° C, more preferably from 285 to 320 ° C. Spinning temperature is 280 ℃
If it is less than 1, the temperature is too low to be in a stable molten state, the resulting fibers have large irregularities, and no satisfactory strength and elongation are exhibited. On the other hand, when the spinning temperature exceeds 330 ° C., the thermal decomposition becomes severe, and the obtained yarn is colored and does not show satisfactory strength and elongation.

The sheath-core polyester fiber of the present invention can be obtained by being extruded from a spinneret, wound up, and then stretched. To be stretched after winding here means that after spinning, winding is performed on a bobbin or the like, and the yarn is stretched using another device. After cooling and solidifying, it is wrapped several times around the first roll rotating at a constant speed, so that the tension before and after the roll is not transmitted at all, and installed next to the first roll and the first roll It refers to a so-called straight drawing method in which a spinning-drawing process is directly connected, such as drawing with a certain second roll.

The winding speed of the yarn after extrusion from the spinneret is preferably selected so that the sheath polymer is not oriented as much as possible and the core polymer is oriented as much as possible without crystallization. By applying orientation without crystallizing the polymer of the core, the degree of orientation and crystallinity of the polymer of the core can be further increased by stretching and heat treatment subsequent to winding, and the strength of the fiber can be increased. In addition, by not giving an orientation to the polymer of the sheath, the orientation of the polymer of the sheath due to stretching and heat treatment can be suppressed, and the dyeability at low temperatures can be improved. Such a winding speed is preferably from 800 to 4000 m / min, more preferably from 1200 to 3500 m / min, and still more preferably from 1600 to 3000 m / min. Winding speed is 80
At less than 0 m / min, both the sheath and the core of the wound yarn are not oriented. When such a fiber is stretched, the degree of orientation of the sheath polymer is increased together with the core polymer, and not only the dyeability is reduced. Since the core is not sufficiently oriented, the core polymer cannot be sufficiently oriented by stretching, and it is difficult to obtain sufficient strength. Also 400
At 0 m / min or more, the fiber is crystallized without being oriented at the time of winding, so that the stretchability is reduced, and the degree of orientation cannot be sufficiently increased for stretching and heat treatment. It becomes difficult to obtain fibers.

The stretching ratio at the time of stretching depends on the winding speed, but the stretching ratio at which the wound yarn breaks when stretched (rupture stretching ratio, hereinafter abbreviated as BDR) is 100.
% Is preferably 50 to 99%, more preferably 6 to 99%.
It is 0 to 95%, particularly preferably 70 to 90%. If the draw ratio is less than 50% of BDR, it is difficult to obtain a sufficient strength because the fiber cannot be sufficiently oriented. On the other hand, if it exceeds 99%, yarn breakage occurs frequently during drawing, making it difficult to continuously draw the fiber.

The temperature at the time of stretching is 35 to 35 in the stretching zone.
75 ° C is preferred, more preferably 40 to 70 ° C, particularly preferably 45 to 65 ° C. If the temperature of the drawing zone is lower than 35 ° C., yarn breakage occurs frequently during drawing, and fibers cannot be obtained continuously. On the other hand, when the temperature exceeds 80 ° C., the slipperiness of the fiber with respect to a heating zone such as a drawing roll deteriorates, so that single yarn breakage occurs frequently and the yarn becomes full of fluff. In addition, since the polymers slip through each other, sufficient orientation is not obtained, and the elastic recovery rate decreases.

It is preferable to perform a heat treatment after the stretching. This heat treatment is preferably performed at 90 to 190 ° C.
More preferably 100 to 180 ° C., particularly preferably 11
0-170 ° C. When the heat treatment temperature is lower than 90 ° C., as can be seen from the fact that the fiber density does not become sufficiently high, the crystallinity does not become sufficiently high, and it becomes difficult to obtain the high-strength fiber aimed at by the present invention. Alternatively, the dyeing fastness such as the dry cleaning fastness of the dyed product is deteriorated. At a temperature higher than 190 ° C., the fibers are cut in the heat treatment zone and cannot be drawn.

The dyeability of the sheath-core polyester fiber of the present invention can be evaluated by K / S, which is the deep chromaticity when dyed at 110 ° C. using a disperse dye. K / S is preferably 18 or more, more preferably 20 or more. Since the K / S when dyeing ordinary polyethylene terephthalate fiber at 130 ° C. is about 20, the K / S is practically 1
If it is 8 or more, it can be considered that a color developing property close to that of ordinary polyethylene terephthalate fiber is developed. In addition, the dye used for the evaluation of the dyeability has a large molecular structure. Therefore, if high dyeability can be obtained using this dye, high dyeability can be obtained using any type of disperse dye. Can be secured.

In order for the dyed product thus dyed to exhibit high fastness, it is desirable that the fastness to dry cleaning is 3-4 or higher. The dry cleaning fastness in the present invention is an evaluation of liquid contamination. The evaluation items of the fastness include water fastness, washing fastness, sublimation fastness, friction fastness, and the like, but according to the study of the present inventors, dry cleaning fastness is 3-4. It is known that if the grade is equal to or higher than that of the sheath-core polyester fiber of the present invention, all of the remaining fastnesses other than the light fastness are at a level that is industrially acceptable. Accordingly, the fastness to dry cleaning is an index indicating the overall fastness to dyeing of the sheath-core polyester fiber of the present invention. Further, in order to be able to be used for the outer layer, it is desirable that the dyeing conditions of the present invention show a light fastness of 3-4 or higher, preferably 4 or higher, as shown in Examples.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to examples. The main measured values in the examples were measured by the following methods. (1) Intrinsic Viscosity This intrinsic viscosity [η] is a value determined based on the following definition formula.

[0034]

(Equation 1)

Ηr in the definition formula is a value obtained by dividing the viscosity at 35 ° C. of a diluted solution of a polyester polymer dissolved in o-chlorophenol having a purity of 98% or more by the viscosity of the solvent itself measured at the same temperature. It is defined as relative viscosity. C is the solute weight value in grams in 100 ml of the solution. (2) Birefringence (Δn) Using a light microscope and a compensator, it was determined from retardation of polarized light observed on the surface of the fiber. (3) Density The measurement was performed using a density gradient tube made of carbon tetrachloride and toluene. (4) Strength, elongation, elastic modulus Using Orientec Co., Ltd. Tensilon, yarn length 20c
m and the tensile speed were 20 cm / min.
In addition, the modulus of elasticity in the tensile test is 0.5 to
The average value between 2 mm was used. (5) Dyeability {exhaustion rate, deep chromaticity (K / S)} A sample is made of a single-piece knitted fabric of polyester-based composite fiber, and hot water containing score roll 400 at 2 g / liter is used.
After scouring at 70 ° C. for 20 minutes, drying with a tumbler drier, and then using a pin tenter at 180 ° C. for 30 minutes.
The heat set of second was used. The exhaustion rate is 40
After the temperature was raised from 110 ° C. to 110 ° C., the temperature was further maintained for 1 hour, and then evaluated by the exhaustion rate. The dye used was Kayaron Polyester Blue 3RSF (manufactured by Nippon Kayaku Co., Ltd.), and was 6% o.
Wf, dyeing at a bath ratio of 1:50. As a dispersant, 0.5 g / liter of Nikka San Salt 7000 (manufactured by Nikka Chemical Co., Ltd.) was used, and 0.25 ml / liter of acetic acid and 1 g / liter of sodium acetate were added to adjust the pH to 5.

The deep chromaticity, which indicates how deep the color was, was evaluated using K / S. This value is obtained by measuring the spectral reflectance R of the sample cloth after dyeing, and
It was determined from the equation of Kubelka-Munk.
The larger this value, the greater the deep color effect, ie,
Indicates that the color is well developed. As R, the value at the maximum absorption wavelength of the dye was used.

K / S = (1-R) ² / 2R (6) Color fastness Evaluation was made using 500 mg of a single-mouth knitted fabric dyed by the method of (3). Dry cleaning fastness (DC fastness)
Is JIS-L-0860, and the light fastness is JIS-L-
0842, washing fastness according to JIS-L-0844, and dry / wet friction fastness according to JIS-L-0849.

[0038]

Example 1 1,3-propanediol (hereinafter referred to as TM
G) 1121 parts by weight, dimethyl terephthalate (hereinafter abbreviated as DMT) 1300 parts by weight,
Titanium tetrabutoxide 1.3 as transesterification catalyst
A transesterification reaction was performed at 220 ° C. using parts by weight. Next, 1.3 parts by weight of titanium tetrabutoxide was added as a polycondensation catalyst, and at 260 ° C., a degree of vacuum of 0.5 to
Polycondensation was performed at rr to obtain a polyester polymer used for the sheath. The intrinsic viscosity of the obtained polymer was 0.62.

On the other hand, ethylene glycol (hereinafter referred to as EG,
The transesterification reaction was carried out at 220 ° C. using 915 parts by weight of DMT, 1,300 parts by weight of DMT, and 0.65 parts by weight of manganese acetate as a transesterification catalyst. Next, 0.65 parts by weight of antimony trioxide as a polycondensation catalyst and 0.39 parts by weight of trimethyl phosphite as a stabilizer were added, and polycondensation was performed at 285 ° C. at a reduced pressure of 0.5 torr. Obtained. The intrinsic viscosity of the obtained polymer was 0.68.

The obtained two types of polymer chips were dried at 130 ° C. for 20 hours under a nitrogen stream of 100 ml / min. Then, using the spinning pack shown in FIG.
From the polyester polymer used for the sheath portion, the polyester polymer used for the core portion from B via a gear pump,
Sink, using 36 single-array spinnerets, spinning speed 160
An undrawn yarn was prepared by spinning at 0 m / min.

Next, the obtained undrawn yarn was drawn at a hot roll of 50 ° C., a hot plate of 140 ° C., a draw ratio of 2.6 times (85% of BDR), a drawing speed of 600 m / min, and a twist of 50 denier / 36. A drawn filament was obtained. The ratio of the core diameter of the obtained fiber was 70%.
The physical properties of the fiber were a strength of 3.9 g / d, an elongation of 41%, an elastic modulus of 43 g / d, and a fiber density of 1.359 g / c.
m ³ and Δn of the sheath portion were 0.058.

The obtained fiber was heated at 110 ° C. using a disperse dye.
The K / S of the dyed product stained with 2 was 20.9. This result shows that the sheath-core polyester fiber of the present invention has a
This shows that the dyeability at 0 minutes is equivalent to the dyeability of the polyethylene terephthalate fiber according to the ordinary method at 130 ° C. for 60 minutes. In the dry cleaning fastness of the one-knit fabric after dyeing, no fading of the dyed product was observed, and the liquid contamination was grade 4-5. In addition, light fastness (4-5)
Grade), fastness to dry / wet friction (grade 5), fastness to washing (grade 5)
Was also good.

[0043]

Examples 2 and 3 Polymerization and spinning experiments were conducted in the same manner as in Example 1 except that the ratio of the core was changed. Table 1 shows the results.
Summarized in All of the polyester fibers had good properties such as good dyeability, strength and elastic modulus.

[0044]

Comparative Examples 1 to 3 Polymerization and spinning experiments were performed in the same manner as in Example 1 except that the ratio of the core was changed. Table 1 shows the results.
Summarized in Neither of the polyester fibers was able to satisfy both good dyeability and an appropriate elastic modulus at the same time.

[0045]

Comparative Example 4 Polymerization and spinning were carried out in the same manner as in Example 1 except that 1,327 parts by weight of 1,4-butanediol was used instead of TMG. Table 1 shows the results. Although the obtained fiber could be dyed at 110 ° C., it had poor dry cleaning fastness.

[0046]

Example 4 and Comparative Examples 5 and 6 Polymerization and spinning were carried out in the same manner as in Example 1 except that the winding speed and the draw ratio were changed. Table 2 shows the results. The yarn having a winding speed of 2000 m / min within the range of the present invention had good properties such as good dyeing properties, strength, and elastic modulus. But spinning speed 600
The yarn at a m / min or 5000 m / min spinning speed did not have sufficient strength.

[0047]

Comparative Example 7 Polymerization and spinning were carried out in the same manner as in Example 1 except that the draw ratio was 1.8 times, which is 45% of NDR. Table 2 shows the results. The obtained fiber not only did not have sufficient strength, but also had a low elastic modulus.

[0048]

Comparative Example 8 Polymerization and spinning were carried out in the same manner as in Example 1 except that the temperature of the hot roll was changed to 30 ° C. However, many yarn breaks occurred during drawing, and continuous fibers could not be obtained.

[0049]

Comparative Example 9 Polymerization and spinning were carried out in the same manner as in Example 1 except that the temperature of the hot roll was 90 ° C. However, since the yarn was fused to the hot roll during stretching, single yarn breakage occurred frequently, and the resulting fiber was full of fluff.

[0050]

Comparative Example 10 Polymerization and spinning were carried out in the same manner as in Example 1 except that the temperature of the hot plate was 70 ° C. Fibers were obtained without problems such as yarn breakage and fluff. However, the obtained fiber has a density of 1.
It was as low as 29 g / cm ³ , the strength was as low as 4.3 g / d, and the dry-cleaning fastness of the dyed product was grade 3 and poor in fastness.

[0051]

Comparative Example 11 Polymerization and spinning were carried out in the same manner as in Example 1 except that the temperature of the hot plate was changed to 200 ° C. The fibers broke at the hot plate and could not be stretched.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

The sheath-core polyester fiber of the present invention can be dyed with a disperse dye at 110 ° C. or less, has a strength of 3.5 g / d or more, an elastic modulus of 40 to 70 g / d or less.
It is a fiber characterized by good heat setting properties and excellent fastness. Since it has high strength and an appropriate elastic modulus, it is possible to obtain a fabric having excellent handleability during post-processing such as weaving knitting and having a soft texture. For this reason, it can be mixed with a fiber which is difficult to dye at a normal dyeing temperature of polyethylene terephthalate fiber, and can exhibit a soft texture.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one example of a spinning pack used when producing a sheath-core polyester fiber of the present invention.

[Explanation of symbols]

 AB: polymer inlet 1: horizontal channel 2: capillary 3: spout

Claims (1)

[Claims] 1. A polyester fiber comprising a sheath and a core, wherein the sheath comprises a polyester polymer comprising terephthalic acid as an acid component and trimethylene glycol as a glycol component, and the core comprises terephthalic acid as an acid component; A sheath-core polyester fiber comprising a polyester polymer containing ethylene glycol as a glycol component, wherein the ratio of the core diameter to the fiber diameter is 40 to 90%.