JPS6350445B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel anti-pilling polyester fiber, and more particularly to a low elongation polyester fiber having excellent anti-pilling properties equivalent to cotton. Conventionally, knitted fabrics using natural fibers have less pilling (pilling), but compared to this, knitted fabrics using synthetic fibers are known to have the disadvantage of more pilling. There is. In order to solve this problem, many proposals have been made since Japanese Patent Publication No. 35-8562, in which a method of imparting anti-pilling properties to polyester fibers uses a low-viscosity polymer from the perspective of reducing the strength and imparting anti-pilling properties. However, these methods result in lower tenacity due to lower viscosity, which significantly reduces operability in the spinning and post-processing stages, increases costs, and requires other qualities to be improved in order to obtain anti-pilling properties. There were problems such as having to make sacrifices. For this reason, a number of methods have been proposed since Japanese Patent Publication No. 32-5844 to impart anti-pilling properties through chemical treatment, etc. in the post-processing stage, but post-processing methods have low productivity, process)
It had the disadvantage of high costs due to problems and other issues. In addition, as a method to eliminate these drawbacks, a method of increasing the strength by lowering the nodule strength has been proposed in Japanese Patent Application Laid-open No. 49-26516, Japanese Patent Publication No. 51-43089, etc., but these methods are also different from the above-mentioned method. Similarly, the problem of operability in the spinning and drawing stage due to the use of low viscosity polymers has not been fully resolved, and because of the low knot strength, improvements have only been made to card passability in the spinning stage.
It has not yet been possible to increase productivity at all stages of spinning. Since the cause of this is low viscosity, methods for manufacturing anti-pilling fibers using high viscosity polymers have been proposed in Japanese Patent Publication No. 47-9854 and Japanese Patent Application Laid-open No. 52-148221, etc.; Even with the method using a high viscosity polymer, excellent pill resistance equivalent to that of cotton has not been obtained, and with the method using a low viscosity polymer
△n spun at a spinning take-off speed of 3500 m/min is 10×
JP-A-49-71214 discloses that an anti-pilling fiber is obtained by drawing an undrawn yarn of 10 ^-3 to 80 x 10 ^-3 in two stages.
Furthermore, it is known that anti-pilling fibers can be obtained by drawing undrawn polyester fibers with a birefringence of 0.04 to 0.08 obtained at a spinning take-off speed of 2500 to 4500 m/min to 1.3 to 2.5 times at 50 to 90°C. However, as with the prior art described above, the current situation is that these methods do not provide anti-pilling properties to the same level as cotton. The present inventors have conducted extensive research in order to solve the above problems and obtain a pill-resistant polyester fiber that has excellent pill-resistant properties equivalent to cotton, is inexpensive to produce, and has good post-processing properties. As a result, we finally arrived at the present invention which achieves the intended purpose. Intrinsic viscosity (phenol/tetrachloroethane:
When melt-spinning a linear polyester whose polyester has a polyester (measured at 30°C in a 6/4 mixed solvent) of 0.5 to 0.8 and 85 mol% or more of the repeating units are ethylene terephthalate, it is possible to use a spinneret to produce irregular cross-section yarn. The spun yarn is taken at a take-up speed of 4000 m/min or more to develop oriented crystallization in the spun yarn, and to obtain an undrawn yarn with a shrinkage rate of 10% or less under dry heat at 160°C. Then, the undrawn yarn was stretched in the first stage at a temperature of 70 to 130°C and a stretching tension of 0.4 to 0.8 g/
d. Second stage stretching conditions are temperature 130-200℃, stretching tension
After stretching at 0.6 to 0.8 g/d, relax heat treatment is performed,
Next, the third-stage drawing condition is a fiber obtained by drawing at a temperature in the range of 200°C to fusion temperature and a drawing ratio of 1.2 to 1.3 times, and which is characterized by having the following properties at the same time: Pillable polyester fiber. (a) Initial tensile resistance (IS); 40≦IS (g/d)≦100 (b) Apparent crystal size of 010 plane (ACS ₀₁₀ )≧50
(c) Tensile elongation (DE)<10% The polyester component forming the polyester fiber of the present invention has ethylene terephthalate units as a main constituent unit, and usually contains 85 mol% or more of ethylene terephthalate units. Polyester or homopolyester or a polyester mixture thereof. Copolymerization components other than terephthalic acid and ethylene glycol include isophthalic acid, adipic acid, sebacic acid, azelaic acid, naphthalic acid, p-oxybenzoic acid, 2,5
-dimethylterephthalic acid, bis(p-carboxyphenoxy)ethane, 2,6-naphthalene dicarboxylic acid, hexahydroisophthalic acid, 3,5-di(carbomethoxy)benzenesulfonic acid metal salt,
diethylene glycol, propylene glycol,
Examples include 1,4-butanediol, 1,4-hydroxymethylcyclohexane, and derivatives thereof. Examples of the third component to be mixed with polyester include polyamide (nylon 6, nylon 66, nylon 6, 10, aromatic polyamide, etc.), polyethylene, polypropylene,
Polymers that can be melt-spun by mixing with polyester polymers such as polystyrene, antioxidants, antistatic agents, flame retardants, dye improvers, dyes, pigments, matting agents, transparency improvers. , a fluorescent whitening agent, a crystallization promoting nucleating agent, and the like. Of course, these third components may be chemically bonded to the polyester polymer. The initial tensile resistance (hereinafter abbreviated as IS) referred to in the present invention is measured by the measuring method defined in JISL- _1013-1981 . IS in the present invention is 40 (g/d) or more, 100
(g/d) or less, and if the IS is less than 40 (g/d), there is no appropriate brittleness required for anti-pilling properties, and good anti-pilling properties cannot be obtained. On the other hand, I.S.
If it exceeds 100 (g/d), the impact resistance of the fibers decreases too much, and as a result, anti-pilling properties are imparted, but when made into a fabric, the tear strength decreases, which is not preferable. The apparent crystal size (ACS ₀₁₀ ) of the 010 plane of the fiber in the present invention is defined as the apparent crystal size of the 010 plane of the fiber (ACS 010).
This is the crystal size calculated from the half-value width of the intensity of the 010 plane using the Sherrer equation shown below. For details, see "X-ray Crystallography" published by Maruzen Co., Ltd., supervised by Isamu Nita. ACS=(nλ)/{(√ ² − ² )×cosθ} (In the formula, n is the correction coefficient, λ is the X-ray wavelength (Å), B
is the half width (rad), α is the correction angle (rad), and θ is the diffraction angle (degrees). ) Previously, the present inventors have proposed a polyester fiber that exhibits anti-pilling properties equivalent to cotton, which is a fiber made of linear polyester in which 85 mol% or more of the repeating units are ethylene terephthalate, and which has an apparent crystal of 010 plane. The size (ACS ₀₁₀ ) is 50 Å or more, the ratio of the apparent crystal size of the 010 plane (ACS ₀₁₀ ) to the apparent crystal size of the 100 plane (ACS ₁₀₀ ) (ACS ₀₁₀ /
ACS ₁₀₀ ) is 1.25 or more, tensile strength (DT) is 6 g/d or less, and knot strength (KT) is 3
The invention was completed with the aim of exceeding g/d, but as a result of further research, (ACS ₀₁₀ /
Even in areas where ACS ₁₀₀ ) is less than 1.25, IS is 40
g/d or more, preferably 50 g/d or more, more preferably 65 g/d or more and 100 g/d or less, and the tensile elongation (DE) is less than 10% to obtain the same effect as the above invention, namely The present invention was achieved by discovering that excellent anti-pilling properties equivalent to that of cotton can be obtained. The fibers of the present invention have an ACS ₀₁₀ of 50 Å or more, preferably 60 Å or more, and fibers with an ACS 010 of less than 50 Å do not exhibit excellent pill resistance equivalent to that of cotton. Tensile elongation according to the present invention (hereinafter abbreviated as DE)
was measured using the measurement method defined in JISL- _1013-1981 . In the present invention, the DE must be less than 10%, and if the DE is 10% or more, the appropriate brittleness required to impart pill resistance equivalent to that of cotton cannot be obtained. The fiber of the present invention exhibits excellent pill resistance equivalent to that of cotton by simultaneously satisfying the IS, ACS ₀₁₀ , and DE requirements described above. Compared to conventional polyester fibers for clothing, the polyester fiber of the present invention has significantly different crystal size and elongation, and has an initial tensile resistance of 40 g/d.
or more, preferably 50 g/d or more, more preferably
It has the characteristics of being in the range of 65 g/d or more and 100 g/d or less. That is, ACS ₀₁₀ is 50 Å or more, preferably 60 Å or more, DE is less than 10 (%), and IS is 40 g/d.
or more, preferably 50 g/d or more, more preferably
By satisfying all these requirements of 65 g/d or more and 100 g/d or less, it exhibits excellent pill resistance equivalent to that of cotton in the pilling test described below. The reason for this is not yet clear, but according to the inventors' speculation, the following can be said. The fibers of the present invention have a larger crystal size and a crystal structure grown in the b-axis direction compared to conventional polyester fibers for clothing, so they are strong against tension in the c-axis direction but are resistant to twisting. It is becoming weaker against the accompanying tension. Furthermore, by lowering the elongation, the degree of tension in the amorphous region is increased, resulting in a decrease in impact resistance and moderate brittleness. Therefore, when the fiber is made into a knitted fabric, it has a special effect of extremely promoting the shedding of the generated pills.For these reasons, the polyester fiber of the present invention has the same effect as cotton. It is thought to exhibit excellent anti-pilling properties. The cross-sectional shape of the fibers of the present invention is not particularly limited, but in particular, U-shaped, V-shaped, or shapes with protrusions added thereto, when made into a spun yarn, single fibers are difficult to come off and have good pill resistance. You can get sex. The method for manufacturing the fiber of the present invention will be explained below. The fibers of the present invention are produced by controlling the molecular arrangement of the fibers by combining ultrahigh-speed spinning technology and high-temperature, low-elongation drawing technology. In particular, the most distinctive feature regarding manufacturing is that oriented crystallized yarn is obtained by performing ultrahigh-speed spinning to develop oriented crystallization at the spinning and take-off stages, and this oriented crystallized yarn is
In particular, in multi-stages of three or more stages, the latter stage side is made to have a higher temperature condition than the earlier stage side, and a high degree of tension stretching is performed. In the production of such fibers, in the spinning step, the intrinsic viscosity (measured at 30°C in a mixed solvent of phenol/tetrachloroethane = 6/4) that can be extruded with a melt spinning machine is 0.3 to 1.0, preferably
Oriented crystallized yarn is obtained by ultra-high speed spinning of 0.5 to 0.8 ethylene terephthalate polyester. Examples of methods for determining whether or not oriented crystallized threads have been obtained include (a) confirming the presence or absence of crystals by wide-angle or small-angle X-ray analysis of the threads, and (b) measuring the density of the threads. (3) Measuring the shrinkage rate (hereinafter abbreviated as SHD) of the yarn under dry heat at 160°C, and determining whether the density has increased rapidly or not.
There are methods to judge based on whether or not it is below, but the simplest method is the method using SHD (c) above, and if it is below 10%, it is judged that oriented crystallized thread has been obtained. It's fine. The main purpose of ultrahigh-speed spinning here is to develop oriented crystallization during the spinning and drawing steps, and to form crystal nuclei for promoting crystallization during the subsequent drawing heat treatment. From this point of view, the relationship between spinning speed and oriented crystallization is important. For example, in the case of polyethylene terephthalate (intrinsic viscosity 0.61), the spinning speed at which oriented crystallization is achieved is 4500 m/min or more for round cross-section yarn, but for irregular cross-section yarn ( For example, it has been found that oriented crystallization occurs at a speed of 4000 m/min or more in the case of a cross-section (type 〓). The oriented crystallized yarn is then drawn in three or more stages of drawing. For example, as for the stretching conditions in the three-stage stretching method, the stretching temperature in the first stage stretching is 70 to 130°C, preferably 85 to 125°C, and the stretching ratio is such that the stretching tension is 0.4 to 0.8 (g/denier). It is preferable to select as appropriate so that Here, the stretching tension is 0.4 (g/
denier), stretching spots are likely to occur.
Moreover, if it is higher than 0.8 (g/denier), single thread breakage is likely to occur. It is preferable that the stretching temperature in the second stage stretching is higher than that in the first stage, 130 to 200°C, and the stretching ratio is appropriately selected so that the stretching tension is 0.6 to 0.8 (g/denier). Next, a relaxing heat treatment is performed to grow the crystal size to some extent. The third stage of stretching is preferably carried out at high temperature and high tension, and the stretching temperature is preferably 200° C. or higher and the melting temperature or lower, and the stretching ratio is preferably 1.2 to 1.3 times. By the method described above, (a) 40≦IS (g/d)≦100
It is possible to obtain polyester fibers that simultaneously satisfy (b) ACS ₀₁₀ ≧50Å and (c) DE<10%. When the fiber thus obtained is used as a stable, it is mechanically crimped using a push-type crimper or the like, and cut into a desired length to form a stable. When mechanically crimp is applied, if it is applied at room temperature, sufficient crimp will not be obtained and the entanglement during spinning will be reduced, resulting in disadvantages such as preheating to 120℃ or higher to hot crimp. preferable. The fibers made stable by the method described above are
It has excellent spinnability, weavability, and knitting properties, and the knitted fabric has superior pill resistance compared to conventionally known anti-pilling polyester fibers using low-viscosity polymers, and its level is comparable to that of cotton. indicates the equivalent grade. The denier of the fiber of the present invention is not particularly limited, but
Depending on the intended use, it is preferable to select an appropriate material according to the intended use, such as 1 to 1.5 denier for the cotton blend type and 2 to 5 denier for the wool blend type. The fibers of the present invention can be used as single-material woven or knitted fabrics, as well as blended yarns and processed yarns in combination with different types of fibers other than the fibers of the present invention, as well as mixed fabrics, knitted fabrics, and non-woven fabrics with different types of fibers or yarns made of different types of fibers. It also exhibits excellent anti-pilling properties on heavy fabrics, multi-layered woven and knitted fabrics, etc. Applications of the fiber of the present invention include dress shirts,
Casual shirts, women's blouses, women's skirts, underwear, slacks, men's formal wear, women's formal wear, knitwear,
Sportswear, coats, outwear in general, babywear, children's clothing in general, men's suits, jackets, blousons, uniforms in general, kimonos, household items (aprons, tablecloths, gloves, hats, etc.), bedding or sleeping clothes (futons, sheets, etc.) , futon covers, pajamas, etc.), interior goods, carpets, and other industrial materials. The fibers of the present invention will be explained below using examples.
The present invention is not limited to these Examples. The method for measuring fiber properties in Examples is as follows. (a) Anti-pillar properties According to JIS- _L1076-1976 method A. (b) Initial tensile resistance, tensile strength, tensile elongation and knot strength According to JIS- _L1013-1981 . However, the load-elongation curve was obtained by measuring under the following conditions. After leaving the sample in a constant temperature room at 20℃ and 65% relative humidity for 24 hours, it was tested using a Tensilon UTM-type tensile tester (manufactured by Toyo Baldwin).
Measurement was performed with a sample length of 2 cm and a tensile rate of 2 cm/min. (c) Crystal size According to the method described above. Note that an X-ray generator (Rotary Flex, manufactured by Rigaku Denki) was used to measure the crystal size of the fibers. This measurement requires X-ray
A Cu-Kα ray (λ=1.5418 Å) was used, a correction coefficient n of 0.9, and a correction angle α of 6.98×10 ⁻³ (rad). Example 1 Intrinsic viscosity 0.63 obtained by polycondensation of terephthalic acid and ethylene glycol in a mixed solvent of phenol/tetrachloroethane = 6/4 by a conventional method.
Polyethylene terephthalate (measured at °C) was spun at a spinning temperature of 290 °C,
0.05mm, the cross-sectional area of a single hole is 0.3mmO/equivalent to a round hole)
The spun yarn is spun from a spinneret with 24 nozzles at a discharge rate of 0.95 g/min per single hole, and the spun yarn is asymmetrically spun by blowing cooling air at room temperature at a speed of 0.9 m/sec from one side of the yarn. It was taken over at a speed of 4000 m/min while being cooled. The birefringence of the yarn is 0.08, and the SHD is 6%.
It was hot. Next, this yarn is heated to a roller temperature of 80
℃, one step of stretching at a heating plate temperature of 120℃ and a draw ratio of 1.3 times, then a second step of stretching at a heating plate temperature of 150℃ and a draw ratio of 1.05 times, followed by dry heat at 160℃. Heat treatment in a hot air zone with a relaxation rate of 20%, followed by heating plate temperature
The third stage of stretching was performed at 230° C. and a stretching ratio of 1.3 times. The resulting drawn yarn had a denier of 1.58 (d), a strength of 3.7 (g/d), a DE6 (%), and an IS90 (g/d). The drawn yarn was aligned to 50,000 denier, and while preheating at a preheating temperature of 180°C, mechanical crimping was applied using a push-in crimper with a number of crimps of 15 (crests/2.5 cm) and a crimp degree of 13 (%) to a length of 38 mm. Amputated. The obtained stable was made into a spun yarn with an English thread count of 30 ^S and a twist coefficient of 3.2 using a conventional method.
A knitted fabric in which pilling is particularly likely to occur was selected from the spun yarn, and the knitted fabric was subjected to a pilling test after scouring.
That is, an interlock knitted fabric with a basis weight of 200 g/m ² was created, and scouring {Neugen HC2 (g/), Na ₂ CO ₃ 0.5
(g/) After treatment at 70℃ for 20 minutes in aqueous solution, 50℃
The anti-pilling properties of the knitted fabrics, which had been washed with water for 10 minutes, were evaluated using an ICI pilling tester. Table 1 shows the properties of the fibers and the results of anti-pilling evaluation. Here, as a comparative example, an interlock knitted fabric of the same basis weight was made using the same spun yarn of ₁₀₀ % cotton and the same _twist coefficient as in the above example.
), Arturin AP80 1 (g/), Hyper
After boiling for 30 minutes in N0.35 (g/) aqueous solution, 50
After washing with water at ℃ for 10 minutes, the pill resistance was evaluated in the same manner as in the above example. The results are shown in Table 1. As a result of the comparison with cotton mentioned above, the fiber of the present invention showed excellent pill resistance comparable to that of cotton fiber. Example 2 A polyester yarn that was oriented and crystallized and spun under the same conditions as in Example 1 was drawn in one step at a stretching ratio of 1.3 times at a heating roller temperature of 80°C and a heating plate temperature of 120°C, and then at a heating plate temperature of 220°C. The second stage of stretching was carried out at a stretching ratio of 1.10 times at 160°C.
Heat treatment was performed in a dry heat hot air zone at a relaxation rate of 20%, followed by a third stretching at a heating plate temperature of 230°C and a stretching ratio of 1.0 times. The obtained drawn yarn was made into staples in the same manner as in Example 1. The obtained staple was subjected to a pilling test as a knitted fabric in the same manner as in Example 1, and its anti-pilling properties were evaluated. Table 1 shows the evaluation results of staple properties and anti-pilling properties. The fiber of this example exhibited excellent pill resistance comparable to that of cotton. Example 3 A polyester yarn that had been oriented and crystallized and spun under the same conditions as in Example 1 was drawn in the same manner as in Example 1, except that the third stage drawing ratio was 1.25 times. The drawn yarn was made into staples in the same manner as in Example 1. The anti-pilling properties of the obtained staples were evaluated in the same manner as in Example 1. Table 1 shows the evaluation results of staple properties and anti-pilling properties. The fiber of this example, which met the requirements of the present invention, exhibited excellent pill resistance comparable to that of cotton. Comparative Example 1 A polyester yarn spun in the same manner as in Example 1 was heated at a heating roller temperature of 80°C and a heating plate temperature of
Stretched at 120℃ with a stretching ratio of 1.36 times, then 155℃
After being subjected to relaxation heat treatment for 3 minutes, it was mechanically crimped in the same manner as in Example 1 and cut into 38 mm pieces. The obtained staple was evaluated for pill resistance in the same manner as in Example 1. Table 1 shows the evaluation results of staple properties and anti-pilling properties. The anti-pilling property of this example was inferior to that of the fiber of the present invention, and the spinnability was also poor. Comparative Example 2 A polyester yarn spun in the same manner as in Example 1 was stretched under the same stretching conditions as in Comparative Example 1. A polyester staple was obtained in the same manner as in Comparative Example 1, except that the drawn yarn was not subjected to the relaxing heat treatment, and the anti-pilling property was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results of staple properties and anti-pilling properties.
The fiber of this example has an ACS ₀₁₀ of less than 45 (Å), and has extremely poor anti-pilling properties when compared to the fiber of the present invention. Comparative Example 3 A polyester yarn spun in the same manner as in Example 1 was drawn under the same stretching conditions as in Comparative Example 1, and the resulting drawn yarn was subjected to relaxation heat treatment at 155°C for 3 minutes, and then again at a temperature of 180°C and a stretching ratio. Stretched at 1.1x and again at 155
It was subjected to a relaxation heat treatment at ℃ for 3 minutes, mechanically crimped in the same manner as in Example 1, and cut into 38 mm pieces. The anti-pilling properties of the obtained staples were evaluated in the same manner as in Example 1. Table 1 shows the evaluation results of staple properties and anti-pilling properties. In this example, the IS value is 40 (g/d)
The strength is also lower to 2.8 (g/d), and the anti-pilling properties are worse than the fibers of the present invention, and the spinnability is also inferior. Comparative example 4 Discharge amount per single hole 0.5g/min, cooling air speed 2.0m/
The undrawn yarn was obtained under the same spinning conditions as in Example 1 except that the take-up speed was 1300 m/min, and the drawing ratio was 2.2 times.
One stage of stretching was carried out at a roller temperature of 80°C and a heating plate of 130°C. The drawn yarn was heated to 135 at a relaxation rate of 25%.
It was subjected to a relaxation heat treatment for 10 minutes at °C, mechanically crimped in the same manner as in Example 1, and then cut into 38 mm pieces. Table 1 shows the characteristics of the obtained staple and the evaluation results of anti-pilling properties evaluated in the same manner as in Example 1. In the case of this comparative example,
The ACS ₀₁₀ is small, and the DE is greater than 10%, resulting in inferior anti-pilling properties compared to the fibers of the present invention. Comparative Example 5 An undrawn polyester yarn with an SHD of 43% was obtained under the same conditions as in Example 1, except that the cooling air velocity was 0.2 m/sec and the take-up speed was 3500 m/min. This undrawn yarn was stretched at a total stretching ratio of 1.35 times at both the first and second stage roller temperatures of 80°C and heating plate temperature of 130°C, followed by relaxation heat treatment in dry heat at 155°C for 5 minutes, and then preheated at 180°C. Machine crimped and cut to 38mm. Table 1 shows the characteristics of the obtained staple and the anti-pilling properties evaluated in the same manner as in Example 1. Although the crystal size is large due to sufficient heat treatment, the DE is large at 27%, and the anti-pilling property is inferior to the fiber of the present invention. Comparative Example 6 Polyethylene terephthalate was spun from a spinneret with 300 holes at a spinning temperature of 270°C and a spinning take-off speed of 2500.
An undrawn yarn tow having an intrinsic viscosity of IVf0.38 and a birefringence Δn of 25×10 ⁻³ was obtained by melt spinning at a speed of m/min. Two devices each having upper and lower heating plates installed between two rollers having different circumferential speeds were installed, and using this device, the undrawn tow obtained above, which had been spun for more than 7 days, was It was stretched in stages. The stretching conditions are as follows:
3.0 times at 180℃, and 1.2 times at 180℃ in the second stage.
This drawn tow was crimped using a staff box type crimper, then subjected to dry heat treatment at 160° C. for 1 minute, and cut to 38 mm to produce a staple for spun yarn. The yarn physical properties of the staple are shown in Table 1.
This staple was used to make a spun yarn with an English yarn count of 30 ^'s , and the anti-pilling properties of the interlock knitted fabric were evaluated. The spinnability, stretchability, spinnability of this yarn,
Table 1 shows the evaluation results for knitting properties and pill resistance. Comparative Example 7 Polyethylene terephthalate was melt-spun from a spinneret with 300 holes at a spinning temperature of 270° C. and a winding speed of 1000 m/min to obtain an undrawn yarn tow. The intrinsic viscosity IV _f of this yarn was 0.38. This unstretched tow was meandered through three pins at 90°C and was stretched in the first stage at a stretching ratio of 2.6 times, and then at a stretching ratio of 180°C.
℃ plate to double the second stage, then crimped with a staff box type crimper.
Dry heat treated at 160℃ for 1 minute and cut into 38mm pieces.
A short fiber for spinning with a single yarn denier of 1.2 denier was obtained.
The physical properties of this yarn are shown in Table 1. This short fiber was used to make a spun yarn with an English thread count of 30'S, and the pill resistance of the interlock knitted fabric was evaluated. Table 1 shows the evaluation results of spinnability, stretchability, spinnability, knitting ability, and pill resistance of this yarn. Comparative Example 8 Polyethylene terephthalate with an intrinsic viscosity of 0.61 was spun from a spinneret with 500 holes and a spindle diameter of 0.4 mmφ at a temperature of 280°C, a spinning draft of 444, and a spinning take-off speed of 3500.
Melt spinning was performed at m/min, cooling air blowing length in the spinning tube of 20 cm, and cooling air temperature of 25° C. to obtain a highly oriented undrawn polyester tow. Using this unstretched tow, stretch in a hot water bath at a stretching speed of 100 m/min and at a first hot water bath temperature of 70 m/min.
Two-step stretching was carried out at a second hot water bath temperature of 85°C so that the total stretching ratio was 1.7. After stretching, the fibers were crimped using a push crimper, heat treated at 120°C, and then cut to a length of 51 mm to obtain staple fibers. Table 1 shows the yarn physical properties of the staple fiber. This staple fiber was used to make a spun yarn with an English count of 30'S, and the pill resistance of the interlock knitted fabric was evaluated. The evaluation results of spinnability, stretchability, spinnability, knitting property, and anti-pilling properties of this yarn were evaluated in the first step.
Shown in the table.

【table】

[Table] * Polyethylene terephthalate sheet ** Intrinsic viscosity of undrawn yarn

Claims (1)

[Claims] 1. Intrinsic viscosity (measured at 30°C in a 6/4 mixed solvent of phenol/tetrachloroethane) is 0.5 to
0.8. When melt-spinning a linear polyester in which 85 mol% or more of the repeating units are ethylene terephthalate, use a spinneret with a spinning hole that can produce yarn with irregular cross-sections, and use a take-up speed of 4000 m/min. The spun yarn is taken in the above manner to develop oriented crystallization to obtain an undrawn yarn with a shrinkage rate of 10% or less under dry heat at 160°C, and then the drawn yarn is stretched at a temperature of 70 to 70°C. 130℃, stretching tension 0.4~
0.8g/d, second stage stretching condition is temperature 130~200℃,
A fiber obtained by stretching at a stretching tension of 0.6 to 0.8 g/d, followed by relaxation heat treatment, and then stretching at a stretching ratio of 1.2 to 1.3 times in the third stage stretching conditions of a temperature range of 200°C to a melting temperature, which is as follows. A low-elongation, anti-pilling polyester fiber characterized by having the following properties at the same time. (a) Initial tensile resistance (IS); 40≦IS (g/d)≦100 (b) Apparent crystal size of 010 plane (ACS ₀₁₀ )≧50
Å (c) Tensile elongation (DE) <10%