JPH07310227A - Nylon 66 multifilament yarn - Google Patents

Abstract

PURPOSE:To obtain nylon 66 multifilament yarns suitable e.g. for blending and orthoblending with polyester fibers, etc., having specific physical properties and causing very little yellowing in a setting process, free from embrittlement even by wet-heat treatment at a high temperature, exhibiting flexibility and excellent in hand feelings, dyeability, etc. CONSTITUTION:This nylon 66 multifilament yarn has the following characteristics; the initial modulus at 20 deg.C and 60% RH is 15-45g/d, the peak height of dynamic loss tangent (tandelta)max and the peak temperature [Tmax ( deg.C)] satisfy the formula, the peak temperature is <=95 deg.C, the crystallite size (ACS) is 40-60Angstrom , the crystal orientation (CO) of the (100) plane is >=85% and the birefringence (DELTAn) at the center of the fiber is 37X10<-3> to 50X10<-3>. Further, the yarn has 55-100 milli-equivalent amino terminal group based on 1kg yarn. The monofilament denier of this filament is preferably within the range of 0.3-1.0.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to improved nylon 66 multifilament yarns with reduced yellowing and brittleness.

[0002]

BACKGROUND OF THE INVENTION Nylon 66 fiber is used in various clothing applications because it has excellent strength, durability, stretchability, high melting point, and good heat resistance among nylon. However, compared with nylon 6, the level dyeing property is inferior, and stains are likely to occur. In order to solve this, JP-A-57-14351
Japanese Patent Laid-Open No. 4 discloses a nylon 66 fiber having a special fine structure and excellent in levelness. Furthermore, since the nylon 66 fiber has a low initial modulus, it is possible to obtain a fabric having high flexibility and good texture by using this.

In recent years, in the textile industry, the trend toward fashion has progressed, and fabrics are required to have functions such as high bulkiness and elegant texture. The use of a mixed product with other materials, and wrinkle processing for giving wrinkles to the cloth at the dyeing processing stage have also been used as effective means for giving the above-mentioned function. However, in the post-processing step of a fabric such as a mixed product with polyester fiber or a wrinkled product, it is usually not used for nylon fiber.
High temperature wet heat processing conditions of ° C are required. Nylon fiber,
The use of such high-temperature wet heat processing conditions has a drawback that the strength retention rate is significantly reduced.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above drawbacks and provides a nylon 66 multifilament yarn which is extremely soft and has a good texture with little strength embrittlement even under high temperature wet heat processing conditions. It is provided.

[0005]

SUMMARY OF THE INVENTION The present invention is provided at 20 ° C. and 60 ° C.
The initial modulus at% RH is 15 to 45 g / d, and the peak height (tan δ) of the mechanical loss tangent (tan δ) is
δ) _max and the peak temperature (T _max [° C.]) satisfy T _max ≦ −320 (tan δ) _max +132, the peak temperature is 95 ° C. or less, and the crystallite size (ACS) is 40 Å or more and 60 Å or less. The degree of crystal orientation (CO) of the (100) plane is 85% or more, and the birefringence (Δn) at the center of the fiber is 37 × 10 ⁻³ or more and 50 × 10 ^−3.
The nylon 66 multifilament yarn is characterized in that it has 55 to 100 milliequivalents of amino end groups per 1 kg of the yarn.

In order for the filament yarn of the present invention to have practically satisfactory properties as nylon 66, 20
The initial modulus at 60 ° C. and 60% RH must be 15 g / d or more. Therefore, the birefringence (Δn) at the central portion of the filament yarn needs to be 37 × 10 ⁻³ or more. Here, the birefringence is measured by an interference microscope by the method described later.

Regarding the filament yarn of the present invention,
There is the following relationship between the fine structure and the mechanical and thermal properties. Various parameters (fine crystallite size (ACS), (100) crystal orientation (CO), which represent the fine structure of the crystal part of the fiber, are the mechanical properties of the fiber (tensile elongation, initial modulus) and thermal properties. It is related to the properties (dimensional stability, stability of fine structure to heat), the filament yarn of the present invention has satisfactory tenacity and modulus, modulus,
Further, ACS and CO are preferably 40 Å or more and 85% or more, respectively, from the viewpoint of imparting dimensional stability and stability of the microstructure to heat. More preferable values of these parameters are 45 Å or more and 87% or more, respectively. If ACS is less than 40Å,
The change in the microstructure tends to increase with temperature rise or moisture absorption, and the strength tends to decrease when heat is applied, or the dimensional stability during wet or heating tends to decrease. On the other hand, if CO is less than 85%, the initial elastic modulus decrease upon heating tends to increase.

Here, parameters such as ACS, CO, CPI and IWR are measured by the X-ray diffraction method described later. On the other hand, when the initial modulus exceeds 45 g / d, the fibers tend to be rigid, and the nylon 6 of the present invention is used.
6 The softness characteristic of the multifilament yarn is impaired.

Generally, the dyeability of nylon fibers depends on the amino terminal groups and the fine structure in the case of dyeing with an acid dye and on the fine structure in the case of dyeing with a disperse dye. The influence of the structure and its variation is large, and stains are likely to occur. In the present invention, (tan δ) _max and T _max are used in order to improve the level dyeing property of nylon 66 and prevent the occurrence of uneven dyeing in the product.
Must satisfy 80 ≦ T _max ≦ −320 (tan δ) _max +132.

Conventionally obtained by a conventional spinning-drawing method
The fine structure of nylon 66 fiber is, for example, the draw ratio.
Changes significantly depending on the difference of
δ) _maxAnd T_maxWhen expressed by the relationship between both characteristic values of_max≧ −320 (tan δ)_maxLimited to +140 range. It should be noted that conventional practical Nair for clothing
66 fiber T_maxIs between 110 and 140 ° C,
(Tan δ)_maxIs between 0.09 and 0.15. This
Against this, T_max≦ −320 (tan δ)_maxWhen +132 is satisfied, there is little change in the microstructure with time and the average is uniform.
Dyeability is significantly improved, and even at lower temperature, sufficient depth is obtained.
A dyeing is obtained.

(Tan δ) of the filament yarn of the present invention
_The larger the _max value, the better the dyeability and flexibility, but
The dimensional stability and the thermal stability of the microstructure are reduced. Therefore,
(Tan δ) _max is preferably 0.15 or less. Regarding T _max , in order to lower the dyeing temperature, the lower it is, the better. Generally, T _max ≦ 95 ° C. is preferable. The lower limit of T _max does not have to be particularly set, but in the present invention, it is 80 ° C. or higher. In the present invention, the content of amino end groups of the fiber should be 55-100 meq / kg of polymer (or yarn). Fibers having an amino end group content of less than 55 milliequivalents / less than 1 kg of polymer undergo embrittlement due to high-temperature wet heat treatment at 120 to 130 ° C., and the resulting fabric becomes unsatisfactory for ordinary use.

The amount of amino end groups is 100 meq /
A polymer having a polymer content of more than 1 kg has a low polymer polymerization degree, and is a fiber having a poor level of mechanical properties in practical use. Thus, by combining with a special fiber structure capable of obtaining an extremely soft texture and the amount of amino terminal groups in the fiber, it has a soft texture in which the embrittlement of the strength due to the high temperature wet heat treatment is suppressed. Nylon 66 multifilament yarn can be obtained.

The single yarn denier of the nylon 66 multifilament yarn of the present invention is preferably 3 denier or less, which is usually used. However, the denier of 1.0 to 0.3 denier is in addition to the softness derived from the above fiber structure. The most preferable is that the flexibility derived from the form in which the single yarn denier is extremely thin is added. Further, the nylon 66 multifilament yarn of the present invention has (combined with) the feature that yellowing is small.

Usually, after the synthetic fibers are woven into a knitted fabric,
After scouring and dyeing, a pre-set and finishing set are required after these treatments. In the case of knitted fabric of nylon 66 multifilament yarn, a temperature of around 180 ° C. is used in the preset or finishing set. In the conventional nylon 66 multifilament yarn, yellowing occurs in this setting process and the appearance of the product is impaired. On the other hand, in the nylon 66 multifilament yarn of the present invention, yellowing occurs in the setting process. Very few, the appearance of the product is significantly improved.

Nylon 66 used in the present invention is mainly composed of condensation polymerization of hexamethylenediamine and adipic acid, but is typically represented by a small amount of additives such as titanium oxide. A matting agent, an antistatic agent such as polyethylene glycol, a heat stabilizer such as hindered phenol, and a polymerization degree controlling agent such as alkylenediamine and alkylamine may be contained.

Further, a small amount of copolymerization component may be contained within a range that does not deteriorate the physical properties of the nylon 66 multifilament yarn. The polyhexamethylene adipamide used in the present invention is produced by ordinary melt polycondensation, and may be a batch polymerization method or a continuous polymerization method. For example, as a batch polymerization method, a 50% by weight aqueous solution of hexamethylene diammonium adipate (AH salt), which is a salt of hexamethylenediamine and adipic acid, is mixed with an additive such as a polymerization degree adjusting agent and charged into a concentrating tank.
Heat to around 0 ° C. and concentrate to a concentration of about 80% by weight. This concentrated solution is supplied to the polymerization tank and heating is continued. At this time, the pressure in the polymerization tank is adjusted to about 18 kg with the pressure control valve.
The condensation water is removed while the temperature is controlled to / cm ² , and the internal temperature is raised to 250 ° C. Next, while continuing heating, the pressure in the polymerization tank is gradually released to normal pressure, and the internal temperature is raised to 2
The temperature is raised to 80 ° C. and kept for several tens of minutes to complete the polycondensation. The produced polymer melt can be pressurized with an inert gas, extruded from a discharge mouthpiece, and cooled to form pellet chips.

As the continuous polymerization method, Brit.
P. 674,954 (1949) and Adv. Poly.
Tech. , 6, (3), 267 (1986) and the like. Furthermore, even if the degree of polymerization is further increased, the polymer chips obtained by the above-mentioned polymerization method are heated at a temperature 20 to 80 ° C. lower than the melting point in a reduced pressure vacuum or in an inert gas for solid phase polymerization. good.

In these general polymerization methods, in order to regulate the amino terminal group concentration to a predetermined amount, it is most preferable to add hexamethylenediamine, which is one component of the raw material, in excess when the raw material is charged. Simple and effective. It can also be achieved by adding hexamethylenediamine during the polymerization. Further, other diamine compounds can be used, and the amino terminal group concentration can be increased by adding them at the time of charging the raw materials or during the polymerization.

The VR (relative viscosity of formic acid) of the present invention may be appropriately set according to the application, but when it is usually used for clothing,
It is 30-60. The nylon 66 multifilament yarn of the present invention can be obtained, for example, by spinning the above nylon 66 polymer at a high speed of 4000 m / min or more, as shown in the examples. During spinning, the polymer viscosity, the spinning temperature, the atmospheric conditions under the spinneret, and the spinning speed are appropriately controlled to control the cooling and solidification of the polymer stream melt-spun from the spinneret, and the thinning deformation to improve spinnability. In addition, a nylon 66 multifilament yarn having desired characteristics can be obtained.

Here, the spinning speed means the speed of the first driving roll which, when a cooled and solidified yarn is required, is further bundled and treated with a finishing agent and then taken at a predetermined speed. FIG. 1 shows an example of the apparatus used in the present invention. The melted nylon 66 is spun from a spinneret (not shown) mounted in the spinning head 2 heated to a predetermined temperature and cooled in the atmosphere to form the yarn 1. In this device, a tubular heating region 3 surrounding the spun yarn 1 is provided immediately below the spinneret.
And a fluid suction device 4 for sucking and cooling the yarn is installed below the heating area.
The yarn 1 that has passed through the tubular heating region 3 and the fluid suction device 4.
Passes through the finishing agent application device 5 and the focusing device 6 and then the take-up roll 7
Taken over by.

The nylon 66 multifilament yarn of the present invention can be used in a field having a very high level of required level of dyeing property, and a fabric having a high flexibility and a good texture can be obtained. In addition, there is no mixed product with polyester or the like, and there is no embrittlement in strength due to the high temperature moist heat treatment necessary for wrinkle processing, and this makes it possible to use it in various fields of apparel applications.

The nylon 66 multifilament yarn of the present invention can be used as a processed yarn or as it is for knitted fabrics and other clothing applications. The method for measuring the structural characteristics and other characteristics of the filament yarn used in the present invention will be described below. (1) Mechanical loss tangent (tan δ) The mechanical loss tangent (tan δ) is measured using a VIBRON type manufactured by Orientec. Measuring frequency 110H
z, temperature rising rate 10 ° C./min, tan δ-temperature (T) characteristic is measured in dry air. tan δ-Ta from temperature curve
The nδ peak height (tan δ) _max and the tan δ peak temperature T _max (° C) are obtained.

FIG. 2 shows the tan of the filament yarn of the present invention.
A delta-T curve is shown typically. (2) Birefringence (Δn) For the measurement of birefringence, a transmission interference microscope manufactured by the former East Germany Carl Zeiss Jena is used. Wave amount 549mμ, temperature 25
From the values of the refractive index n ₁₁ for light oscillating parallel to the filament axis and the refractive index n ⊥ for light oscillating perpendicularly to the filament axis at

[0024]

[Equation 1]

It is represented by In addition, the central portion of the filament is defined as the center of gravity when the filament cross section is considered to be one plane for both the circular cross section and the atypical cross section filament. (3) Apparent crystallite size (ACS) ACS can be obtained by measuring the X-ray diffraction intensity in the equatorial direction by the symmetric reflection method.

The X-ray diffraction intensity was measured by Rigaku Denki (RU-2
00PL) and a goniometer (SG-9R), a scintillation counter for the counting tube, and a wave height analyzer for the counting unit, and the measurement is performed with CuKα rays (λ = 1.5418Å) monochromated with a nickel filter. The filament yarn sample is set in the AI sample holder so that the filament axis is perpendicular to the X-ray diffraction plane. At this time, the thickness of the sample should be about 0.5 mm. 30KV, 80
Run the X-ray generator at mA and scan speed 2θ,
1 ° / min, chart speed 10 mm / min, time constant 1 second, divergence slit 1/2
Angle, receiving slit 0.3 mm, skiuttering slit 1/2 °, diffraction angle 2θ of 7 ° to 35 °
Record the diffraction intensity up to °. The full scale of the recorder is set so that the obtained diffraction intensity curve falls within the scale, and at least the maximum intensity value does not exceed 50% of the full scale.

The filament yarn of the present invention is generally characterized by having two main reflections within the range of the equatorial line diffraction 2θ = 20.0 ° to 24.5 ° ((1
The (00) plane is the (010) + (110) plane on the high angle side). The method used to determine ACS is, for example, LE
Alexander, "Polymer X-ray Diffraction," published by Kagaku Dojin,
Chapter 7 Using the Scherrer formula.

The diffraction intensity curves between 2θ = 7 ° and 35 ° are connected by a wire to form a baseline. Draw perpendicular to the baseline from the apex of the diffraction peak and fill in the midpoint between the peak and the baseline. A horizontal line passing through the midpoint is drawn between the diffraction intensity curves. This line is
If the two major reflections are well separated, they intersect the two shoulders of the peak of the curve, but 1 if the separation is poor.
It only intersects one shoulder. The width of this peak is measured. When crossing only one shoulder, measure the distance from the intersection to the midpoint and double. When crossing two shoulders, measure the distance between them. These values are converted to radians and used as the line width. Further, the line width is corrected by the following method.

[0029]

[Equation 2]

B is the measured line width, and b is the broadening constant, which is the line width (half-value width) in radians of the peak of (111) plane reflection of the Si single crystal. The apparent crystallite size is given by: ACS (Å) = K. λ / B. cos θ where K is 1, λ is the wavelength of X-ray (1.5418Å),
β is the corrected line width, θ is the Bragg angle 1 / of 2θ
It is 2.

(4) Crystal orientation degree (CO) The crystal orientation degree of the filament yarn is measured by X
A line generator (RU-200PL), a fiber sample measuring device (FS-3), a goniometer (SG-9), a scintillation counter for the counting tube, a wave height analyzer for the counting unit, and a monochromatic CuKα with a nickel filter ( λ =
It is measured at 1.5418Å).

The filament yarn of the present invention is generally characterized by having two major reflections on the equator line. CO
A reflection with a low angle 2θ is used for the measurement. The 2θ of reflection used is determined from the diffraction intensity curve in the equatorial direction. The X-ray generator operates at 30 KV and 80 mA.
The sample is attached to the filament yarn sample measuring device so that the single yarns are parallel to each other. It is suitable that the thickness of the sample is about 0.5 mm. The goniometer is set to the 2θ value determined from the diffraction intensity curve in the equatorial direction. Using the symmetric transmission method, the azimuth direction is −
Scan 30 ° to + 30 ° and record the diffraction intensity in the azimuth direction. Further record the diffraction intensity in the azimuth direction of -180 ° and + -180 °. At this time, scanning speed 4 ° / m
m, chart speed 10 mm / min, time constant 1 second, collimator 2 mmφ, receiving slit vertical width 1.9 mm, horizontal width 3.5 mm.

From the obtained diffraction intensity curve in the azimuth direction, C
To obtain O, the average value of the diffraction intensities obtained at ± 180 ° C. is taken and the horizontal line is drawn as the baseline. A perpendicular line is drawn from the apex of the peak to the base line, and the midpoint of the height is obtained. A horizontal line passing through the midpoint is drawn, the distance between the intersection of this horizontal line and the diffraction intensity curve is measured, and the value obtained by converting this value into an angle (°) is taken as the orientation angle H. The crystal orientation degree is given by the following equation. CO (%) = (180−H) / 180 × 100

(5) Crystal perfection (CPI) The X-ray diffraction intensity curve obtained from the ACS measuring method is used for measuring the crystal perfection (CPI). Crystal perfection (CP
To obtain I), the method of Dismore and Staton is used, and the CPI is given by the following equation. Here, A is 0.189, and the closer the CPI value is to 100, the higher the degree of crystal perfection. [Crystal Growth Rate (IWR)] To measure the crystal growth rate, AC
The X-ray diffraction intensity curve obtained from the S measurement method is used. The crystal growth rate (IWR) is It is represented by.

Here, H ₁ is (100) plane reflection and {(0
10) + (110)} plane reflection is the minimum intensity, H ₂ is the maximum intensity of the (100) plane reflection, and H ₃ is the maximum intensity of the {(010) + (110)} plane reflection. Is.
The closer the IWR value is to 1, the higher the crystal growth. (6) Strength and elongation, initial modulus TENSIRON UTM-II manufactured by Orientec Co., Ltd.
It was measured by a conventional method using a -20 type tensile tester. The measurement atmosphere is 20 ° C. and RH 60%.

(7) Shrinkage rate of boiling water: The sample length under a load of 0.1 g / d was Lo, treated with no load for 30 minutes in boiling water, and then the length L was again measured under a load of 0.1 g / d. To measure. Boiling water shrinkage ratio BWS (%) is expressed by BWS (%) = (Lo-L) / _Lo × 100.

(8) VR (Relative Viscosity of Formic Acid) 8.4% by weight of nylon 66 is dissolved in a 90% formic acid solution and measured at 25 ° C. by a conventional method. (9) Dye spot occurrence rate The sample was false twisted, and the obtained processed yarn was formed into a tubular knitted fabric, and
cid Alizarin Liquid Blue 4
GL 0.5% owf, acetic acid and ammonium acetate were added to adjust the pH to 5.0, the temperature was raised from room temperature to 98 ° C in 60 minutes, the temperature was kept at 98 ° C for 10 minutes, and then the temperature was lowered to give a dyed knitted fabric. Then, the presence or absence of spots is visually judged.

The occurrence rate of spots is Express with. (10) Amino End Group Concentration The yarn is washed with an aqueous solution of a nonionic surfactant having a concentration of 100 times by weight and a concentration of 2 g / liter at 60 ° C. for 30 minutes to remove the finishing agent. Polymer Analysis Handbook "edited by the Japan Society for Analytical Chemistry (published by Asakura Shoten) 32
The method of page 3 was used for analysis. (11) Strength retention rate by high temperature wet heat treatment The yarn is used as a tubular knitted fabric, and after scouring, high temperature wet heat treatment is performed at 130 ° C for 30 minutes at a bath ratio of 1:50 using a dyeing machine. After the treatment, the knitted fabric was unwound, the strength was measured, and the strength retention rate was calculated by the following equation.

[0039] (12) Heat yellowing A single-pitch knitted fabric is prepared, refined, and then left to dry.

Then, it was placed in a hot air oven and heat-treated at 190 ° C. for 5 minutes in an air atmosphere. By measuring the color of the knitted fabric subjected to this treatment with a spectrocolorimeter SZ-Z90 manufactured by Nippon Denshoku Industries Co., Ltd.
I asked.

[0041]

Example 1 Raw materials were charged into an autoclave having a capacity of 400 liters in the following proportions to carry out batch polymerization. 270 liters of 50% by weight aqueous solution of AH salt, 4.2 liters of 14% by weight aqueous solution of hexamethylenediamine, 0.4 liters of 8% by weight aqueous solution of titanium oxide. Concentration was carried out to a weight percentage. Next, the mixture was sent to a polymerization tank, heating was continued, the condensation water was removed while controlling the internal pressure to 17.5 kg / cm ² , the temperature was raised to 250 ° C., and polymerization was allowed to proceed for 1.5 hours. Next, the internal temperature was raised to 280 ° C., the pressure was gradually returned to normal pressure over 1 hour, and the temperature was kept for 30 minutes to complete the polymerization.

The polymer obtained had a VR of 45 and an amino end group concentration of 80 meq / kg. This polymer has a spinning temperature of 305 ° C., a diameter of 0.25 and a number of holes of 3
After melt-spun from the spinneret of No. 4 and cooled and solidified by a cooling air of 20 ° C. supplied from one side of the yarn from a position 10 cm below the spinneret, a finishing agent was applied, and then drawn at various take-up speeds 70d / 34f Nylon 66 multifilament yarn was obtained.

Table 1 shows the structural characteristics and common characteristics of the obtained nylon 66 multifilament yarn. In addition, the occurrence rate of stain spots is obtained by processing the filament yarn at a processing temperature of 220 ° C. and a twist number of 3
It was measured using a false twisted yarn at 200 times / m. Table 1
In No. 2 to No. No. 4 is an example of the fiber of the present invention, which has good mechanical properties sufficient for practical use, has an excellent leveling property, and has a high strength retention rate by the high temperature wet heat treatment. No. No. 1 is an example of a fiber having a large (tan δ) _{max and a} small T _{max, which} is out of the range of the present invention, but has poor mechanical properties and a high incidence of stain spots.

[0044]

[Table 1]

[0045]

Example 2 In the same manner as in Example 1, except that the amount of hexamethylenediamine charged as a raw material was changed in polymer polymerization and adipic acid was added instead of hexamethylenediamine, the amino terminal group was prepared. Nylon 66 polymers with different concentrations were obtained. Table 2 shows the VR and amino terminal group concentrations of the obtained polymer.
These polymers were melt-spun at 295 ° C. from a spinneret having 34 holes with a hole diameter of 0.25φ using a device shown in FIG. 1 and passed through a heating cylinder having a diameter of 100 mm, a length of 20 cm, and an ambient temperature of 200 ° C. After that, a fluid suction device (fluid pressure 0.5 kg / cm ² G) installed 80 cm below the spinneret
The yarn is sucked, cooled, and treated with a finishing agent, and then taken up at a take-up speed of 5000 m / min, 70d / 34f
Nylon 66 multifilament yarn was obtained.

Table 2 shows their structural characteristics and practical characteristics. No. Nos. 5 to 6 are examples of the fiber of the present invention, which have good mechanical properties and level dyeing property, and have little strength embrittlement due to high temperature wet heat treatment. No. Although Nos. 7 and 8 have good mechanical properties and level dyeing properties, they are significantly embrittled by heat and humidity at high temperature and have a large degree of yellowing (YI value).

[0047]

[Table 2]

[0048]

INDUSTRIAL APPLICABILITY The nylon 66 multifilament yarn of the present invention makes it possible to obtain a fabric which is extremely soft and has a good feel, and has little strength embrittlement even by high temperature wet heat processing such as dyeing. To do. The nylon 66 multifilament yarn of the present invention can improve the quality of a dyed and processed fabric of a mixed fiber or a mixed woven fabric with a polyester multifilament yarn or the like. Further, the nylon 6 of the present invention
The 6-multifilament yarn has very little yellowing in the setting process performed after the moistening treatment such as scouring and dyeing, and makes it possible to provide a good-looking fabric product.

[Brief description of drawings]

FIG. 1 is a schematic view of a spinning device used in an example of the present invention.

FIG. 2 is a graph schematically showing a mechanical loss tangent (tan δ) -temperature (T) curve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thread 2 Spinning head 3 Cylindrical heating area 4 Fluid suction device 5 Finishing agent application device 6 Focusing device 7 Take-up roll

Claims (2)

[Claims] 1. The initial modulus at 20 ° C. and 60% RH is 15 to 45 g / d, and the mechanical loss tangent (ta
nδ) peak height (tan δ) _max and peak temperature (T
_max [° C.]) satisfies T _max ≦ −320 (tan δ) _max +132, the peak temperature is 95 ° C. or less, and the size of microcrystal (ACS) is 40 Å or more and 60 Å or less (100) The degree of crystal orientation (CO) is 85% or more and the birefringence (Δn) in the center of the fiber is 37 × 10 ⁻³ or more 50
X10 ^-3 or less and 55 to 1 per 1 kg of fiber
Nylon 66 multifilament yarn characterized by having 00 meq of amino end groups. 2. The nylon 66 multifilament yarn according to claim 1, wherein the filaments constituting the yarn have a single yarn denier of 0.3 to 1.0.