JPH0135086B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to polyester fibers, and more particularly to polyester fibers that have practically sufficient mechanical properties and good dyeability, particularly those that can be dyed by atmospheric pressure dyeing and have excellent color fastness. Generally, polyester fibers, particularly polyethylene terephthalate fibers, have many excellent properties such as strength and dimensional stability, and are used for various purposes. On the other hand, polyethylene terephthalate fibers have poor dyeability and require special equipment as they must be dyed at high temperatures and pressures around 130°C, and they are not compatible with fibers such as wool and acrylic whose physical properties deteriorate due to high pressure dyeing. It has drawbacks such as restrictions on mixed use. Several attempts have been made to improve the dyeability of polyethylene terephthalate fibers and to make them dyeable under normal pressure.For example, a method using a carrier during dyeing is known, but it requires a special carrier, and It has drawbacks such as difficulty in processing. In addition, polyethylene terephthalate with improved dyeability is known by copolymerizing metal sulfonate group-containing compounds and polyether, but although these modified polyesters have improved dyeability, they are difficult to polymerize and spin. Alternatively, the excellent properties inherent to polyethylene terephthalate may be deteriorated, and furthermore, there have been disadvantages such as poor color fastness. In the end, it is inevitable that the above-mentioned chemical modification of the polymer to make it easier to dye will also change the original properties of polyethylene terephthalate because a third component that can serve as a dyeing seat is mixed into the polymer. I can say that. The present inventors have overcome the drawbacks of such conventional methods and have developed a polyester fiber that has good dyeability, can be particularly pressure-dyed, has excellent color fastness, and has the fine structure of a polyester fiber that also has desirable properties. As a result of extensive research, it was discovered that the above object could be achieved by a fiber having a specific amorphous structure, which was previously unknown, and the present invention was achieved. That is, the present invention provides a fiber consisting essentially of polyethylene terephthalate having an initial modulus of 55 g/d or more at 30°C,
The peak temperature (Tmax) of mechanical loss tangent (tanδ) at 110Hz is 105℃ or less, the peak value ((tanδ)max) is 0.14 or more, and the crystallinity Xc
is 30% or more, the crystallite size (ACS) of the (010) plane is 35 Å or more, and the degree of crystal orientation (Co) of the (010) plane is 85% or more. This invention relates to dyeable polyester fibers. The polyester used in the present invention consists essentially of polyethylene terephthalate and can be obtained by known polymerization methods. Of course, copolymerization with small amounts of other components is also possible within a range that does not impair the purpose of the present invention. The polyester may contain additives normally used in polyesters, such as matting agents, stabilizers, antistatic agents, etc. Further, there is no particular restriction on the degree of polymerization as long as it is within the range for normal fiber formation. The first feature of the polyester fiber of the present invention is the mechanical loss tangent (tan δ) at a measurement frequency of 110 Hz.
The peak temperature (Tmax) of is 105°C or less, and the peak value ((tan δ)max) is 0.14 or more. When Tmax is higher than 105°C, dyeability decreases and normal pressure dyeing becomes impossible. The inventors found that when Tmax is so high and (tanδ)max is 0.14 or more, the thermal stability of the fiber structure decreases, dimensional stability deteriorates, and color fastness decreases. Only then did it become clear. However, after examining the microstructure and dyeability of fibers in detail, we found that
If Tmax exceeds 105℃, or Tmax
Regardless of the value of , the initial modulus at 30℃ is
When the temperature is less than 55 g/d, there is a tendency for the thermal stability to decrease as the (tan δ) max increases as described above, but this is not necessarily the case when Tmax is 105°C or less and the initial modulus at 30°C is 55 g/d or more. No trend is observed; on the contrary, the thermal stability of the fiber structure may even increase with increasing (tan δ) max. This tendency of stabilization of the fiber structure becomes remarkable when Tmax becomes 100°C or less. The present invention was completed by the discovery of these facts. That is, the initial modulus at 30℃ is 55
g/d or more, Tmax is 105°C or less, and (tan δ) max is 0.14 or more. Polyethylene terephthalate fibers can be dyed under normal pressure without reducing thermal stability, dimensional stability, and mechanical properties. , and the color fastness does not decrease. The initial modulus of the present invention at 30°C is 55g/
The (tan δ) max value of polyethylene terephthalate fibers with a Tmax of 105°C or more is 0.14 or more, but when the (tan δ) max value is 0.14 to 0.30, the dyeability is further improved and it is easy to dye. It becomes a sexual thing. Of course, even in this case, thermal stability, dimensional stability, mechanical properties, color fastness, etc. do not deteriorate. For conventional polyester fibers, Tmax is
The temperature is 120℃ or higher. (tan δ) max approximately corresponds to the amount of amorphous area dyed by the disperse dye, and the higher the value of (tan δ) max, the better the dyeability. Furthermore, Tmax is related to the degree of tension of the molecular chains in the amorphous region and the density of the aggregated structure; the lower the temperature, the more relaxed the molecular chains are, and the looser the aggregated structure. Therefore, the lower the Tmax, the better the stainability. Conventionally, birefringence Δ _o or amorphous modulus M _A has been proposed as a parameter reflecting the structure inside the amorphous region. however,
There is no good correlation between these physical property values and stainability. On the other hand, (tan δ) max and Tmax have a very high correlation with stainability as described above. As mentioned above, the Tmax of the polyester fiber for clothing that has been spun at a spinning speed of 2000 m/min or less by a conventional method and then subjected to a drawing process is 120°C or higher,
(tanδ)max is around 0.1. In addition, the fiber that has been spun at a spinning speed of 4,000 m/min or more and less than 7,000 m/min and wound up has its (tan δ)
max exceeds 0.135, Tmax exceeds 105°C, and is not dyeable under normal pressure. Furthermore, the spinning speed
For fibers that have been spun at a spinning speed of around 3000 m/min and wound up, (tan δ)max is 0.2 or more, and Tmax
is below 105℃, but the initial modulus is 45g/d.
or less, and the tensile elongation is about 100%, making it a soft and stretchy fiber that does not have the characteristics of a polyester fiber. Such fibers with low initial modulus and elongation tend to cause trouble in the twisting, weaving, and knitting processes and exhibit various defects, so they cannot be used as they are. Generally, when polyester fiber is subjected to drawing treatment, Tmax increases and (tanδ)
max decreases. Also relatively low temperature i.e. 200 ~
When heat treated at 220°C or lower, Tmax increases and (tan δ)max decreases, which is outside the scope of the present invention, regardless of whether stretching is performed in the heat treatment process. Therefore,
The initial modulus of the present invention is 55 g/d or more, Tmax
A polyester fiber that satisfies the three requirements of 105°C or less and (tan δ) max of 0.14 or more can be said to exceed conventional technical knowledge. In addition, in the present invention, in order to obtain the properties as a polyester, the initial modulus at 30°C must be
It is necessary that it is 55g/d or more. For this purpose, the birefringence (Δ _o ) is usually 35×10 ⁻³ . Here, the initial modulus at 30°C means the dynamic modulus of elasticity (E′ ₃₀ ) at 30°C, and its measurement method will be described later. As (tan δ)max increases, E′ ₃₀ generally needs to increase in order to provide excellent mechanical properties and thermal stability. If E′ ₃₀
If it is less than 55 g/d, the thermal stability of the fiber structure will decrease, the dimensional stability will also be poor, and the fiber will become soft. As a result of further examining the relationship between the structure and mechanical properties (strength, elongation, initial modulus, dynamic elastic modulus) and dyeability of the fibers of the present invention having these characteristics, the following was clarified. . In the fiber of the present invention, crystallinity (Xc),
(010) crystallite size (ACS) and (010)
The degree of crystal orientation (Co) of the plane is related to the mechanical properties of the fiber, and the fiber of the present invention has sufficient strength (3 g/d or more) and elongation (20-60
%) and initial modulus (≧55g/d), Xc is 30% or more, ACS is 35Å or more, and Co is
It must be 85% or more. The preferred range is Xc 75% or more, ACS 40Å or more, and Co 90%.
That's all. Here, Xc, ACS, and Co are values measured by X-ray diffraction using the methods described below. Next, in the fiber of the present invention, the central average refractive index (n _(p) ) of polarized light with an electric field vector in the fiber axis direction
If it is smaller than 1.70 and 1.65 or more, it has appropriate elongation (20 to 60%) and dyeability, and is preferable as a clothing fiber. The optimal range for (n _(p) ) is 1.65 to 1.68. In addition, the average birefringence (Δ _o ) of the fiber of the present invention is
In order to have an initial modulus of 55 g/d or more at 30°C, it is 35 × 10 ^-3 or more, but on the other hand, it is desirable to have a modulus of 50 × 10 ^-3 or more in terms of structural stability against heat. From the viewpoint of dyeability and color fastness, it is preferably 110×10 ⁻³ or less, even more preferably 85×10 ⁻³ or less. When Δ _o becomes less than ¹¹⁰
E′ ₁₅₀ , E′ ₂₂₀ and expressed as E′ ₂₂₀ /E′ ₁₅₀ ) becomes smaller and E′ ₂₂₀ /E′ ₁₅₀ becomes larger than 0.75. In other words, the structure becomes stable against heat. The color fastness is also improved. Further, those having Δ _o of less than 85×10 ^-3 have extremely excellent normal pressure dyeability. The following relationship is established between the average refractive index (n _(p) ) at the center of the fiber and the refractive index n (0.8) or n (−0.8) at a distance of 0.8 times the radius from the center of the fiber. Satisfying that the so-called local average refractive index distribution of the fiber is symmetric about the fiber center,
It has sufficient strength and has few staining spots, strong elongation spots, etc.
Here, the local average refractive index distribution is symmetrical with respect to the center of the fiber if the minimum value of the average refractive index n is (n _(p) ) −10×10 ^-3 ) or more, and
This refers to the case where the difference between n _(-0.8) and n _(0.8) is 50×10 ^-3 or less, more preferably 10×10 ^-3 or less. Furthermore, the above
The values of n _(p) , n _(0.8) , n _(-0.8) , Δ _{o (0.8-0)} , Δ _o, etc. were measured using an interference microscope using the method described above. In addition, in the fiber of the present invention, the smaller the mechanical loss tangent (tan δ ₂₂₀ ) at 220°C, the better;
The decrease in initial modulus due to temperature rise becomes smaller. When tan δ ₂₂₀ is 0.25 or less, the amount of initial modulus reduction becomes significantly small. In other words, the fiber has a structure that is extremely stable against heat. For example, the structural change before and after boiling water treatment at 100°C for 60 minutes is extremely small; the change in Tmax is ±5°C, and the change in (tan δ)max is ±0.02. As shown in the examples later, the fiber of the present invention is produced by spinning a yarn at a high speed of 4000 m/min or higher and once wound, and then heat-treating the yarn at a temperature of 230°C or higher and 265°C or lower to increase the elongation of the yarn during heat treatment. It is obtained by heat treatment for 0.5 to 10 seconds with the ratio adjusted to -20% (ie, 20% relaxation) or more and less than +5%. During spinning, the cooling solidification and thinning deformation of the polymer flow spun from the spinneret are controlled by appropriately adjusting the polymer viscosity, spinning temperature, atmospheric conditions under the spinneret, cooling method, take-up speed, etc. Thus, fibers with good spinnability and desired properties can be obtained. In particular, it is important to control the cooling and solidification of the spun yarn, and in order to obtain spinnability and desired properties, rapid cooling and solidification, especially cooling and solidification using low-temperature cooling air perpendicular to the yarn from one direction, is not very desirable. . Note that the take-up speed here refers to the speed of the first drive roll at which the yarn, which has been cooled and solidified after spinning, is taken off after being further bundled, treated with oil, etc., if necessary. FIG. 1 shows an example of the apparatus used in the examples.
The molten polyester is spun from a spinneret (not shown) in a heated spinning head 2 and cooled in the atmosphere to form yarn 1. At this time, a tubular heating area 3 surrounding the spun yarn is provided below the spinneret, and a fluid suction device 4 for cooling and suctioning the yarn is provided below it. The yarn that has passed through the tubular heating zone and the fluid suction device passes through an oil application device 5 and a convergence device 6, and then is taken off by a take-off roll 7. The yarn after being taken off is once taken off by a take-up roll 7, then passes through a non-contact heating tube 9 controlled within ±0.5°C, and taken off by a take-up roll 10. At this time, by adjusting the rotational speed of the rolls 8 and 10, the elongation of the yarn can be accurately adjusted within the range of -20% to +5%. Conventionally, there has been no process in which the high speed spun polyester fibers described above are once wound up and then heat treated for 0.5 to 10 seconds at a high temperature of 230°C or higher at an elongation rate of -20% to +5%. Ta. The fibers of the present invention can be used as filaments as they are, or after undergoing false twisting, fluid processing, etc., alone or in combination with other fibers to make products such as knitted fabrics and woven fabrics. can be used as spun yarn or blended yarn,
When dyeing, it has good dyeability even under normal pressure (100°C), and its unique microstructure shows little structural change even when heat is applied during the product manufacturing process, making it particularly useful as a textile for clothing. Furthermore, in the case of printing, the fibers of the present invention require steaming temperatures of 120 to 130°C in a high-pressure steamer, whereas conventional polyethylene terephthalate fibers require steaming temperatures of 100°C or 130°C in a normal pressure steamer. The dye is sufficiently dyed at a steaming temperature lower than that. Therefore, it is possible to easily print materials mixed with fibers having poor heat resistance such as wool, spandex, and acrylic fibers without causing the fibers to become brittle. The method for measuring the structural properties of the fibers of the present invention will be described below. <Mechanical loss tangent (tanδ) and dynamic elastic modulus (E′)
> Using a Rheo Viblon DDV-c type dynamic viscoelasticity measurement device manufactured by Toyo Baldwin Co., Ltd., approximately 0.1 mg of sample was measured at each temperature in dry air at a measurement frequency of 110 Hz and a temperature increase rate of 10°C/min. Keru
Measure tanδ and E′. From tanδ-temperature curve
The tanδ peak temperature (Tmax) [°C] and the same peak height ((tanδ)max) are obtained. Figures 2a and 2b show the tan δ-temperature curves of the fiber A of the present invention, the conventional drawn yarn B, the undrawn yarn C, and the partially oriented yarn D, respectively.
A typical example of the E'-temperature curve is schematically illustrated. <Average refractive index (n, n⊥) and average birefringence> From the surface measurement of the fiber by the interference fringe method using a transmission quantitative interference microscope (for example, interference microscope Interfaco manufactured by Carl Zeiss Jena, East Germany) The observed average refractive index distribution can be measured. ) This method applies to fibers with a circular cross section. The refractive index of a fiber is characterized by the refractive index n for polarized light with an electric field vector parallel to the fiber axis and the refractive index n⊥ for polarized light with an electric field vector perpendicular to the fiber axis. All measurements described here are performed using green light (wavelength λ =
549mμ). The fibers are made using optically flat glass slides and cover glasses, which have a refractive index (N) that provides a shift of the interference fringes within the range of 0.2 to 2 wavelengths, and are placed in a mounting medium that is inert to the fibers. immersed. Several fibers are immersed in this encapsulant so that the single threads do not touch each other. Furthermore, the fibers should have their fiber axes perpendicular to the optical axis of the interference microscope and the interference fringes. This interference fringe pattern is photographed, magnified approximately 1,500 times, and analyzed. As shown in Figure 3, the refractive index of the fiber encapsulant is N, the refractive index n (or n⊥) between points S' and S'' on the outer periphery of the fiber, and the thickness between S' and S'' is t. , the wavelength of the light beam used is λ, the distance between parallel interference fringes in the background (corresponding to 1λ) is D, and the deviation of the interference fringes due to the fiber is d, then the optical path difference Г is Г=d/Dλ=(n (or n⊥) −N)t. When the radius of the fiber is R, the distribution of the refractive index n (or n⊥) of the fiber at each position can be determined from the optical path difference at each position from the center Ro to the outer periphery R of the fiber. When r is the distance from the center of the fiber to each position, x=r/R=0, that is, the refractive index at the center of the fiber is the average refractive index (n _(p) ) or
It is called n⊥ _(p) ). x is 1 on the outer periphery and has a value between 0 and 1 on the other parts, but for example, the refractive index at the point x = 0.8 is n _(0.8) (or
n⊥ _(0.8) ). Also, the average refractive index n _(p) and n⊥ _(p)
Therefore, the average birefringence (Δ _o ) is expressed as Δ _o =n _(p) −n⊥ _(p) . FIG. 4 shows the conventional drawn yarn B and the fiber A of the present invention.
The distribution of n is shown. In the figure, the distance from the center x=r/R is plotted on the horizontal axis, and n is plotted on the vertical axis, but x=
0 is the center of the fiber, x=1 and x=-1 are points on the outer periphery of the fiber. <Size of Microcrystals (ACS)> The size of microcrystals (ACS) can be determined by measuring the X-ray diffraction intensity in the equator direction using an equatorial reflection method. X-ray diffraction intensity was measured using an X-ray generator (RU-200PL) manufactured by Rigaku Corporation and a goniometer (SG-9R).
A scintillation counter is used as the counter, a pulse height analyzer is used as the counting section, and the measurement is performed using Cu-Kα rays (wavelength λ = 1.5418 Å) made monochromatic with a nickel filter. The fiber sample was placed in an aluminum sample holder so that the fiber axis was perpendicular to the X-ray diffraction plane. At this time, set the sample thickness to about 0.5m/m. Operates X-ray generation at 30kV and 80mA, scanning speed 1°/min, chart speed 10mm/min, time constant 1 second, divergence slit 1/2°, receiving slit 0.3m/m, scattering. List 1/
At 2°, record the diffraction intensity from 2θ of 35° to 7°. The full scale of the recorder is set so that the resulting diffraction intensity curve falls within the scale. Polyethylene terephthalate fibers generally have three main reflections in the equatorial diffraction angle 2θ = 17° to 26° (from the low angle side (100) (010) (110)
surface). An example of an X-ray diffraction intensity curve of a polyethylene terephthalate fiber is shown in FIG. 5 (a in the figure represents a crystalline portion and b represents an amorphous portion). To find ACS, for example, "Polymer X-ray Diffraction" by LE Alexander
Use Scherrer's equation in Chapter 7 of Kagaku Doujin Publishing. A straight line connects the diffraction intensity curves between 2θ = 7° and 2θ = 35° to form the baseline. Draw a perpendicular line from the top of the diffraction peak to the baseline, and mark the midpoint between the peak and the baseline. A horizontal line through the midpoint is drawn between the diffraction intensity curves and the diffraction peaks. 2 of the peaks of the curve if the main reflections are well separated.
It intersects two shoulders, but in case of poor separation it intersects only one shoulder. Measure the width of this peak.
If it intersects only one shoulder, measure the distance between the intersecting point and the midpoint and double it. If it crosses two shoulders, measure the distance between both shoulders.
These measured values are converted into radians and used as the line width. Furthermore, this line width is corrected using the following equation. β=√ ² − ² B is the measured line width, and b is the broadening constant, which is the line width (half width) expressed in radians of the peak of (111) plane reflection of the Si single crystal. The size of the microcrystal (ACS) is given by the following formula: ACS(Å)=K·λ/βcosθ. Here, K is 1, λ is the X-ray wavelength (1.5418 Å), β is the corrected line width, and θ
is the Bragg angle and is 1/2 of 2θ. <Crystallinity (Xc)> X obtained in the same way as measuring the size of microcrystals
From the line diffraction intensity curve, connect the diffraction intensity curves between 2θ = 7° and 2θ = 35° with a straight line to form the baseline. As shown in Figure 5, the valley around 2θ = 20° is the peak,
Connect with a straight line along the base of the low angle side and the high angle side, separate into crystalline part and amorphous part, and calculate by area method according to the following formula. Xe = Scattering intensity of crystal part / Total scattering intensity x 100 <Crystal orientation (Co)> Rigaku X-ray generator (RU-200PL), fiber sample measuring device (FS-3), goniometer (SG- 9), a scintillation counter is used for the counter, a pulse height analyzer is used for the counting section, and Cu-Kα rays (wavelength λ =
1.5418Å). Polyethylene terephthalate fibers generally have three main reflections on the equator line, and the (010) plane reflection is used to measure the degree of crystal orientation (Co). The 2θ of the (010) surface reflection used is determined from the diffraction intensity curve in the equatorial direction. The X-ray generator operates at 30kV and 80mA. Attach the sample to the fiber sample measuring device so that the single yarns are parallel to each other. Sample thickness is 0.5
It is appropriate that the distance be approximately m/m.
Set the goniometer at the 2θ value determined from the equatorial diffraction intensity curve. The azimuthal direction is scanned from −30° to +30° using the symmetrical transmission method, and the diffraction intensity in the azimuthal direction is recorded. Furthermore, the diffraction intensity in the azimuth directions of −180° and +180° is recorded. At this time, the scanning speed was 4°/min, the chart speed was 10 mm/min, the time constant was 1 second, the collimator was 2 m/mφ, and the receiving slit had a vertical width of 19 m/m and a horizontal width of 3.5 m/m. To determine Co from the obtained diffraction intensity curve in the azimuthal direction, take the average value of the diffraction intensities obtained at ±180°, draw a horizontal line, and use it as the baseline. Draw a perpendicular line from the top of the peak to the baseline and find the midpoint of its height. Draw a horizontal line through the midpoint,
The distance between the two intersections of this and the diffraction intensity curve is measured, and this value is converted into an angle (°), and the value is defined as the orientation angle H (°). The degree of crystal orientation is given by the following formula: Co (%) = 180° - H/180° x 100. <Dyeability> Dyeability was evaluated based on the equilibrium dyeing rate. Disperse dye Resolin Blue
Dyeing was carried out at 100° C. using FBL (trade name of Bayer) at a 3% owf. bath ratio of 1:50. as a dispersant
Add 1g/disper TL and further with acetic acid.
Adjust to PH=6. The dyeing rate is determined by the specified time (2 hours)
After the lapse of time, the dye solution was collected, the amount of dye in the remaining solution was calculated from the absorbance, and the amount subtracted from the amount of dye used for dyeing was used to calculate the dyeing rate (%).
In addition, as a sample, raw yarn was knitted into a piece of fabric, scoured at 60℃ for 20 minutes using a score roll FC2g/, dried,
A humidity-controlled (20°C x 65% RH) was used. <Dyeing fastness> A sample was dyed in the same manner as in the dyeability evaluation except that the dye concentration was 1% owf and the dyeing time was 90 minutes. Hydrosulfite 1g/, sodium hydroxide 1g/, surfactant ( Sunmaur RC-700)
The evaluation was made after reduction cleaning using 1g/1 g/l and a bath ratio of 1:50 at 80°C for 20 minutes. Color fastness is light fastness (based on JIS L-1044), rubbing fastness (based on JIS L-0849), and hot-blessing fastness (based on JIS L-0850).
was evaluated. <Initial Modulus> The value of E' at 30°C in the dynamic viscoelasticity test mentioned above was taken as the initial modulus. <Strong elongation> TENSILON UTM manufactured by Toyo Baldwin Co., Ltd.
- Initial length 5 cm, tensile speed 20 using a 20 type tensile tester
Measured in mm/mm. <Boiling water shrinkage rate> When the sample length under 0.1g/load is Lo, and the length L is the length measured under the same load after removing the load and treating it in boiling water for 30 minutes, the boiling water shrinkage rate is boiling water It is expressed as shrinkage rate (%)=Lo−L/Lo×100. The present invention will be explained below using examples. Examples 1 to 4, Comparative Examples 5 to 7 Polyethylene terephthalate, which has an intrinsic viscosity [η] of 0.63 measured at 35°C in a 2/1 mixed solvent of phenol/tetrachloroethane, is spun from a spinneret, and yarn is formed from the entire periphery of the yarn. A finishing agent is applied after being cooled and solidified by a flow of air at 22℃ supplied parallel to the running direction of the strip, and the strip is wound at a speed of 3000 m/min to 7000 m/min. Obtained fiber. Next, this wound fiber was heat treated in a heating cylinder (FIG. 1, 9) set at 240°C±0.5°C for 1 second at an elongation rate of 1.5%. Table 1 shows the relationship between the microstructural characteristics and physical properties of the polyethylene terephthalate fibers obtained.
Examples 1 to 4 in the table are fibers of the present invention, and Examples 5 to 7 are fibers outside the scope of the present invention. It can be seen from Table 1 that the fibers of the present invention of Examples 1-4 have sufficient mechanical properties, thermal stability, normal pressure dyeability, and color fastness. On the other hand, the fibers of Comparative Examples 5 to 7, which are outside the scope of the present invention, are insufficient in any of the above characteristics.

[Table] Stretching ratio in .
Example 5 A polyethylene terephthalate homopolymer having an intrinsic viscosity [η] (hereinafter referred to as [η]) of 0.64 at 35°C was prepared in a 2/1 mixed solvent of phenol/tetrachloroethane using the apparatus shown in FIG. The spinning temperature was 300℃, the hole diameter was 0.35mmφ, and the number of holes was 36.
The fiber bundle is spun from a spinneret, cooled and solidified by a flow of air at 22°C that is supplied from the entire periphery of the fiber bundle in parallel to the running direction of the fiber bundle, and then a finishing agent is applied.
Winding at a speed of 4000m/min to 9000m/min 75d/
A yarn of 36 f was obtained. Next, the yarn was passed through the heating cylinder for heat treatment shown in FIG. 1 without contacting it, and the temperature inside the heating cylinder was adjusted to 240°C.
Heat treatment was performed for 0.85 seconds at an elongation rate of 1%. For comparison, a 75d/36f yarn spun at a spinning speed of 3200 m/min and a 75d/36f fiber spun at a spinning speed of 1300 m/min and then drawn 3.3 times at 30°C were also heat-treated in the same manner. The physical properties of each fiber are summarized in Table 2. From the results in Table 2, it can be seen that when spinning at a spinning speed of 4000 m/min or more according to the present invention and under 1% elongation at 240°C,
Fibers made of polyethylene terephthalate homopolymer heat-treated for 0.85 seconds can be dyed with disperse dyes at normal pressure, have excellent color fastness, and have excellent mechanical properties.
It can be seen that the thermal stability is also sufficiently satisfactory. On the other hand, yarns spun at a spinning speed of 3200 m/min and heat-treated under the same conditions are easier to dye, but have inferior mechanical properties;
A yarn stretched 3.3 times will not become easily dyed even if it is subjected to similar heat treatment.

[Table] Next, using these fibers, 110 warp/2.5
A plain woven fabric with a density of 77 cm and weft/2.5 cm was woven with the warp and weft spinning speeds the same. These fabrics were scoured with hot water at 70°C containing 0.5 g of nonionic surfactant and then dried with hot air at 100°C for 3 minutes. On these fabrics, a printing paste having the composition shown in Table 3 was printed using a 100-mesh hand screen at a rate of 2 g per 1 cm ² of fabric.

[Table] Next, the printed fabric was dried at 80°C for 10 minutes and then steamed at 98°C for 30 minutes in a box-type normal pressure steamer.
Immediately after steaming, the product was washed with water, and then subjected to reduction washing in an aqueous solution containing 1 g of sodium hydrosulfite and 1 g of sodium hydroxide at 80° C. for 10 minutes, and then washed with water for 2 minutes. The printed area of each printed fabric was cut out to an accuracy of 25 cm ² and placed in 30 ml of N,N-dimethylformamide to extract the dye in the printed fabric for 10 minutes at 95°C. This extraction operation was repeated three times, and N,N-dimethylformamide was added to the extract to make it exactly 1, and the dye was dyed using a spectrophotometer UV-360 model (product name of Shimadzu Corporation) to determine the absorbance at a maximum absorption wavelength of 625 nm. I asked for the quantity. The results are shown in Table 4.

[Table] From the results in Table 4, fibers made of polyethylene terephthalate homopolymer having the microstructure shown in Table 2 obtained by spinning at a spinning speed of 4,000 m/min or more according to the present invention and heat-treating at 240°C for 0.85 seconds is 100℃
It can be seen that printing properties are good at the following steam heat.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus used in an embodiment of the present invention. In the figure, 1 is a yarn, 2 is a spinning head, 3 is a tubular heating area, 4 is a fluid suction device, 5 is an oil application device, 6 is a convergence device, 7 is a take-up roller, 9 is a heating cylinder for heat treatment, 8 , 10 are yarn feeding rollers located before and after the heating cylinder for heat treatment, which regulate the elongation rate of the yarn 1 within the heating cylinder for heat treatment, and 11 is a winding roller. FIGS. 2a and 2b are graphs schematically showing a mechanical loss tangent (tan δ)-temperature (T) curve and a dynamic elastic modulus (E')-temperature (T) curve, respectively. FIG. 3 is an example of an interference fringe pattern using measurement of the radial refractive index (n or n⊥) distribution within the fiber cross section. In the figure, a is a cross-sectional view of the fiber, b is an interference fringe pattern diagram, 1 is the fiber, 2 is the interference fringe due to the mounting medium, and 3 is the interference fringe due to the fiber. Figure 4 shows fiber A of the present invention and conventional drawn yarn B.
2 is a graph showing an example of the radial refractive index (n) distribution of . FIG. 5 is a graph showing an example of an X-ray diffraction intensity curve of polyethylene terephthalate fiber.

Claims (1)

[Claims] 1. A fiber consisting essentially of polyethylene terephthalate with an initial modulus of 55 g/d or more, whose peak temperature (Tmax) of mechanical loss tangent (tan δ) at a measurement frequency of 110 Hz is 105°C or less; The peak value [(tanδ)max] is 0.14 or more,
The crystallinity (Xc) is 30% or more, the (010) crystallite size (ACS) is 35 Å or more, and the (010) crystal orientation (Co) is 85% or more. A polyester fiber that can be dyed under normal pressure. 2 Tmax is 100℃ or less, and (tanδ)
max is 0.14 or more, and crystallinity (Xc)
is 70% or more, the size of (010) crystallites (ACS)
50 Å or more, and the degree of crystal orientation (Co) of the (010) plane is 90% or more. 3. The pressure-dyeable polyester fiber according to claim 1, which has a Tmax of 100° C. or less and an average refractive index (n _(p) ) of 1.65 or more and less than 1.70. 4. The polyester fiber according to claim 4, wherein the local refractive index distribution is symmetrical with respect to the center of the fiber.