JPS63120110A - Pilling-resistant polyester yarn - Google Patents

Abstract

PURPOSE:To obtain the titled yarn which consists of a polyester of phosphorus atom-containing polyethylene terephthalate type, has a ratio of knot strength and tensile strength and intrinsic viscosity in specific ranges, shows no difficulty in production process and is inexpensively producible in good productivity. CONSTITUTION:The aimed yarn which is made of a polycondensate consisting of a dicarboxylic acid mainly comprising terephthalic acid and an alkylene glycol mainly comprising ethylene glycol, has 0.36-0.46 intrinsic viscosity, contains phosphorus atoms and has a ratio of knot strength KTg/denier and tensile strength DTg/denier satisfying correlation shown by the equation 0.3<=KT/DT<=0.85. The yarn is preferably obtained by subjecting phosphorus- containing polyester to melt spinning, taking-up yarn at >=1,000m/min, drawing the yarn at 15-45% elongation, subjecting the yarn to relaxation heat-treatment at 5-10% relaxation ratio at 190 deg.C-temperature 10 deg.C lower than the melting point of polyester for 0.3-3sec and subjected to wet heat-treatment at 100-180 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to polyester fibers with excellent anti-build properties (so-called anti-pilling properties).

[Prior art] Polyester fibers, especially polyethylene terephthalate i
A-fibers are used as clothing materials because they have a higher Young's modulus and a higher elastic recovery rate than other synthetic fibers, and they also have excellent durability, chemical resistance, abrasion resistance, etc. It is widely used as a starting point. However, the characteristics of this fiber, such as high tensile strength (DT), high knot strength (KT), and high abrasion resistance, are rather problematic, and when used as knitted fabrics, single threads of the fibers exposed on the surface tend to break. It has the disadvantage that pilling is likely to occur due to fraying, etc., and that once the pilling occurs, it is difficult to fall off, which significantly impairs the appearance. Therefore, it is considered unsuitable for use in high-end clothing.

As a way to improve these drawbacks and provide anti-pillar properties,
■ A method of lowering fiber strength by using a low polymerization degree polyester with an intrinsic viscosity of 0.45 or less, ■ A method of reducing fiber strength by using a high polymerization degree polyester, while ensuring a high level of fiber strength, and improving pill resistance due to the irregular shape of the fiber cross section. Attempts have been made to improve the quality by improving the stretching or stretching methods, and also
As disclosed in Japanese Patent Publication No. 26516 and Japanese Patent Publication No. 51-43089, there are known methods for improving pill resistance by increasing fiber strength while keeping knot strength low.

[Problems to be solved by the invention] However, in the method (2) above, a decrease in strength due to a decrease in the degree of polymerization is unavoidable, and as a result, the operability of spinning and post-processing is significantly reduced, resulting in high costs. There is a problem that other physical properties required for fibers are also adversely affected. In addition, although the above-mentioned method (1) has been confirmed to be somewhat effective on a laboratory scale, sufficient anti-pilling properties have not yet been obtained on an industrial scale. Furthermore, in the method (■) above,
Corresponding to the low knot strength, card passability during the spinning stage is good, but problems remain in the operability of spinning and drawing due to the use of low molecular weight polymers.

The present invention has been made in view of these circumstances, and its purpose is to solve the problems pointed out in the above-mentioned prior art, to provide good anti-pilling properties and other physical properties, and to provide a spinning yarn with good anti-pilling properties and other physical properties. - The aim is to provide anti-build polyester fibers that can be manufactured at high productivity and at low cost without causing any problems at each stage of drawing and spinning.

[Means for Solving the Problems] The structure of the fiber of the present invention that can achieve the above object is made of a condensation polymer of a dicarboxylic acid mainly composed of terephthalic acid and an alkylene glycol mainly composed of ethylene glycol. It is a polyester fiber with an intrinsic viscosity of 0.
36 to 0.46, contains a phosphorus atom, and satisfies the relationship of the following CI] formula.

However, KT means knot strength (g/denier) and DT means tensile strength (g/denier).

[Function] The main acid component of the polyester constituting the fiber of the present invention is terephthalic acid or its ester-forming derivative,
Although the main glycol component is ethylene glycol, other acid components of about 20 mol% or less, such as oxalic acid, malonic acid, maleic acid, glutaric acid, adipic acid, sebacic acid, 1.4- Aliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid and 2,5-norbornanedicarboxylic acid or their ester-forming derivatives, phthalic acid, isophthalic acid, 5-(alkali gold R)sulfoisophthalic acid, siphenic acid, 1,4-naphthalene Contains aromatic dicarboxylic acids such as dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,2-bis(phenoxy)ethane-P, P'-dicarboxylic acid, or their ester-forming derivatives as copolymerization components. There may be. In addition, in an amount of about 20 mol% or less of the acid component,
Oxycarboxylic acids such as (2-hydroxyethoxy)benzoic acid or ester-forming derivatives thereof may also be included.

About 20% or less of the glycol component is glycol other than ethylene glycol, such as propylene glycol, diethylene glycol, neopentyl glycol, 1.4-butanediol, 1.6-hexanediol, 1.4-cyclohexane dimetatool, 1. 10-decamethylene glycol, 4,4°-dihydroxybiphenyl, 1,4-bis(β-hydroxyethoxy)benzene, 2,5-naphthalene diol, glycols with ethylene oxide added to these glycols, polyethylene glycol, etc. It doesn't matter.

In the present invention, the phosphorus atom contained in the polyester fiber is blended as a phosphorus compound, and preferably 5
phosphorus compounds, more preferably phosphoric acid, phosphonic acid and derivatives thereof. Specific compounds include phosphoric acid, alkali metal phosphates, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, monomethyl phosphate, dimethyl phosphate, and monoethyl phosphate. Esters, phosphoric acid diethyl ester, phosphoric acid monobutyl ester, phosphoric acid dibutyl ester, phosphonic acid, alkali metal phosphonic acid salts, methylphosphonic acid, methylphosphonic acid dimethyl ester, ethylphosphonic acid dimethyl ester, phenylphosphonic acid dimethyl ester, benzinephosphonic acid Diethyl ester, phenylphosphonic acid diethyl ester, phenylphosphonic acid diphenyl ester, diethylphosphonoethylpropionate, etc. are exemplified, and these may be used alone or in combination of two or more. Note that phosphorous acid, phosphonic acid, and their derivatives tend to give polyester fibers a strong grayish color, so they are not preferred. In addition, the amount of phosphorus compound added is 700 to 13 in terms of phosphorus atoms to polyester fiber.
00ppm, more preferably 900 to 1l100ppm
It is preferable that the amount is in the range of 1. If the amount is too small, the anti-pilling effect will not be sufficiently exhibited, and if it is too large, the properties of the polyester fiber will be adversely affected.

Next, the intrinsic viscosity of the polyester wlita according to the present invention must be 0.36 to 0.46. In other words, the intrinsic viscosity has a close correlation with the anti-build properties and strength of polyester fibers, and those with an intrinsic viscosity of more than 0.46 cannot provide satisfactory anti-build properties, while those with an intrinsic viscosity of less than 0.36 Although the polyester fiber has good anti-pilling properties, it is not suitable for practical use because the knitting/weaving fabric lacks strength and tends to come out easily. However, the intrinsic viscosity is 0.
Polyester fibers in the range of 36 to 0.46 have moderate strength, and when knitted or woven, they do not tear or tear and exhibit excellent anti-pilling properties.

Another factor that significantly affects the strength and anti-pilling properties of knitted fabrics is the knot strength (KT) of polyester fibers.
and tensile strength (DT) (KT/DT), and as defined in formula [I] above, (KT/DT) is 0.3 to 0.
．． It has become clear that the object of the present invention cannot be achieved unless it falls within the range of 85. That is, (K
For polyester fibers whose T/DT) is less than 0.3,
Since the knot strength is relatively low compared to the tensile strength, the strength when knitted or woven becomes extremely poor, and tearing easily occurs. On the other hand, if (KT/DT) exceeds 0.85, the nodule strength is relatively too high, the rate at which the pill falls off is slow, and the anti-pilling property improvement effect cannot be obtained. On the other hand, if the polyester fiber has a KT/DT) within the above-mentioned preferred range, it will not only have sufficient strength as a knitted or woven fabric, but will also be extremely difficult to form pilling (even if small pill-like particles Even if it is possible, it will fall off immediately)
, excellent anti-pilling properties can be obtained.

As mentioned above, anti-pilling properties are significantly affected by the (KT/DT) ratio. Furthermore, KT and DT are extremely low.
Of course, extremely high values are not desirable.
From this point of view, the preferred KT is 1.0 to 2.5 (
g/denier), DT is 2.5 to 3.5 (g/denier).

Next, a method for producing the anti-pilling ester 1Ali fiber according to the present invention will be explained.

The phosphorus-containing polyester according to the present invention can be produced by esterifying or transesterifying a dicarboxylic acid mainly consisting of terephthalic acid as described above and an alkylene glycol mainly consisting of ethylene glycol, and then performing an optional reaction until the polycondensation reaction is completed. It can be obtained by adding a phosphorus compound as described above at the step. If a phosphorus compound is added before the esterification or transesterification reaction is completed, a large amount of unreacted diethylene glycol will remain and the melting point of the polyester will decrease, which is undesirable. It is best to add it before completion. In the production of the above polyester, transesterification catalysts, esterification catalysts, polycondensation catalysts, and ordinary additives such as matting agents, light stabilizers, antistatic agents, antioxidants, etc. may be used as necessary. Of course, it is also possible.

Melt spinning to obtain the fibers of the present invention can be carried out by any method, but in order to obtain the desired yarn quality through the subsequent drawing and heat treatment, it is necessary to
It is preferable to take over at a speed of 7 minutes or more. If the winding speed is less than 1000 m/min, a sufficient structural modification effect cannot be obtained, and the nodulation speed/tensile strength (KT/DT) ratio of the post-treated product cannot be kept within the above-mentioned specified range. Therefore, the winding speed is 1000 m/min or more, preferably 1500 m 7
It should be at least 1 minute. However, if the winding speed is too high, thread breakage is likely to occur, so it is desirable to keep the winding speed to about 3000 m/min or less.

In addition, the intrinsic viscosity of polyester fiber immediately after spinning is 0.5
If it is lower than 0.5, the melt viscosity during spinning will be too low, resulting in poor spinning operability, and troubles such as yarn breakage will likely occur in subsequent steps. Note that the intrinsic viscosity of polyester fibers is considerably lowered by heat treatment and thermal treatment after spinning, so a polyester with a slightly higher intrinsic viscosity is used so that the intrinsic viscosity of the final product is within the range of 0.36 to 0.45. There is a need.

The spun yarn thus obtained is subjected to stretching treatment if necessary, but the stretching conditions are preferably controlled so that the degree of elongation is in the range of 15% to 45%.

The subsequent heat treatment is an important step in giving the fibers the above-mentioned properties, and it causes structural changes such as an increase in crystal size and non-orientation of amorphous parts, creating a fine structure that improves the fibers. provides appropriate brittleness and drug permeability.

Any method under tension, constant length, or relaxation may be adopted for this heat treatment, but relaxation heat treatment is the most preferable in order to efficiently promote the permeability of chemicals in the subsequent dyeing process.
The optimum relaxation rate is 5-10%. Heat treatment temperature is 190
It is preferable to keep the temperature above 10°C lower than the melting point of the polyester. If the temperature is below 190°C, sufficient structural modification will not occur and sufficient "brittleness" cannot be imparted to the fibers. However, if the heat treatment temperature is too high, "brittleness" is promoted due to growth and increase in crystal size, but it is not preferable because fused threads and the like are more likely to occur.

In addition, the preferable heat treatment time for producing the above-mentioned structural modification effect is 0.3 to 3 seconds; if it is less than 0.3 seconds, sufficient structural modification effect cannot be obtained, while if it exceeds 3 seconds, the tensile strength becomes too high and the anti-building properties decrease.

When the heat-treated fibers obtained in this manner are further heat-treated, polynystyl fibers having the required characteristics specified in the present invention can be obtained. Here, thermal treatment refers to dyeing, refining, weight loss,
It includes a wide range of treatments including dyeing, reduction cleaning, etc., and includes all treatments in which heat is applied in a wet state. The treatment temperature at this time is preferably in the range of 100 to 180°C; if it is less than 100°C, it will take a long time to modify and is not practical, whereas if it exceeds 180°C, there is a risk that the fibers will change in quality and deteriorate.

The pill-resistant polyester fiber of the present invention is obtained by spinning polyester fiber containing a phosphorus compound at a relatively high speed as described above.
The desired performance is obtained by structural modification through heat treatment and thermal treatment, and the reason why the anti-building performance is improved by setting these conditions is thought to be as follows.

It is known that pill resistance can be improved by imparting "brittleness" to fibers, and one way to achieve this is to modify the higher-order structure of fibers by high-speed spinning. That is, it is known that when high-speed spinning is performed, both molecular orientation and crystallinity become higher in the outer layer than in the inner layer, resulting in the development of a non-uniform higher-order structure in the cross-sectional direction of the fiber. It is believed that such structural non-uniformity and the increase in crystal size, especially in the surface layer, give the fiber its "brittleness". However, simply spinning at high speed increases both knot strength and tensile strength, making it difficult to obtain satisfactory anti-pilling properties. Furthermore, if heat treatment is applied after high-speed spinning, the surface layer crystal size will further increase and "brittleness" will be promoted, but even if such a step is added, sufficient anti-build properties may not always be obtained. On the other hand, molecular chain scission (IV reduction) through post-treatment is a method for improving anti-build properties by reducing fiber strength, but in the case of unmodified polyester, almost no change in fiber quality occurs under mild conditions. Furthermore, even if the fiber quality could be reduced by treatment under strong alkaline or acidic conditions, both knot strength (KT) and tensile strength (DT) would decrease, so the (KT/DT) ratio would change. Therefore, the anti-pilling effect as intended by the present invention cannot be obtained. However, in polyester,
Easily hydrolyzable phosphoric acid ethylene glycol ester units are introduced by copolymerization, followed by melt spinning, heat treatment, and thermal treatment to give the fiber a microstructure that provides appropriate "looseness" and drug permeability. As a result, it became clear that the (KT/DT) ratio was small, resulting in a polyester fiber with good anti-pilling performance.Moreover, the anti-pilling fiber of the present invention
Hydrolysis of phosphorus compounds under thermal conditions such as dyeing processes causes molecular chain scission on the surface layer of the fiber, further increasing the "brittleness" of the surface layer of the fiber, resulting in even better anti-pilling properties. .

The compound used in the present invention may be a conductor of phosphoric acid or phosphonic acid, but in order to reduce the knot strength/tensile strength ratio of the fiber after post-treatment, phosphoric acid must be a triethylene which can be hydrolyzed. It is most effective to introduce it in the form of glycol ester, and therefore, phosphoric acid derivatives are particularly preferred as phosphorus compounds.In other words, in the present invention, a polyester modified with a phosphorus compound is synthesized, and then melt-spun and stretched. After imparting brittleness through post-heat treatment, by promoting hydrolysis of the fiber surface layer through heat treatment,
A polyester fiber with a small (KT/DT) ratio and good pill resistance can be obtained.

The anti-build polyester fiber according to the present invention can be applied to a wide range of uses by taking advantage of its excellent anti-build properties, such as dress shirts, casual shirts, women's blouses,
Women's skirts, underwear, slacks, men's formal wear, rezois formal wear, knitwear, sportswear, coats, general outwear, babywear, children's clothing, men's suits, jackets, blousons, dust-free clothing, kimonos, Japanese underwear , Japanese clothing linings, household items (aprons, tablecloths, gloves, hats, etc.), bedding or sleepwear (
Futons, sheets, duvet covers, pajamas, etc.), automotive interior ceiling materials and flooring materials, interior goods, carpets, and other industrial materials, but of course the applications are not limited to these examples.

[Example 7] The present invention will be specifically explained below with reference to Examples and Comparative Examples, but the present invention is not limited to these.

In addition, each measurement item in the Example was measured by the following method.

Extremely viscous (1, V,) 0.1000 g of the test polyester was dissolved in a mixed solvent of phenol/tetrachloroethane (6/4Ii weight ratio).
The relative viscosity (η
rel) is measured and 1. V was calculated.

(W: Sample collection amount = 0.1000g) Fractured bow (D
T and elongation at break (DE) using tensilon, gauge length 2oomm, extension rate 100%/min, initial load 1/3
0. The sample was stretched under the conditions of g/d, and the recording speed was 500 mm.
The strength and elongation at break were calculated from the SS curve drawn at /min.

Knot strength (KT and knot elongation (KE) JIS
It was measured according to the method of L1013-1981.

Anti-pilling properties were measured according to method A of JIS L1076-1985.

Example 1 1000 parts of terephthalic acid, 822 parts of ethylene glycol, and 1.8 parts of triethylamine were charged into a reaction tank equipped with a rectification column, and the inside of the tank was pressurized to 2.5 Kg/ci with nitrogen gas.
The esterification reaction was carried out at a temperature of 0 to 240°C for 120 minutes. Next, this reaction product was transferred to a polymerization reaction tank, and trimethyl phosphate was reduced to 1936 ppm in terms of phosphorus atoms.
/ After adding the polymer and 0.44 parts of antimony trioxide, the temperature was raised and the pressure was reduced until the temperature was 275°C and the pressure was 0.
．． Polycondensation reaction was performed at 1 mmHg for 1 hour, and the intrinsic viscosity was 0 J.
A polyester containing O9, a residual amount of phosphorus atoms of 930 ppm, and a diethylene glycol content of 33.5 mol % was obtained, and this was extruded from the polymerization reaction tank to obtain polyester chips.

After drying this chip in a dryer, it was melt-spun for 2500 m.
The polyester filament was wound up at a speed of 1/min and then heat-treated at a relaxation rate of 8% after stretching at a temperature of 225°C to obtain a polyester filament having an intrinsic viscosity of 0.498.100 denier/48 filament. During this time, there were no troubles in the spinning and stretching processes, such as clogging of the spinning filter or wrapping around the stretching roller, and the spinning, stretching, and heat treatment could be carried out well. Next, this polyester filament was crimped using a crimper and cut into 38 mm. This cut cotton was made into a spun yarn, then made into a tubular knitted fabric, and dyed by dyeing at 130° C. for 60 minutes. The intrinsic viscosity of polyester fiber before dyeing is 0.498
, tensile strength (DT) is 2.98g/d, tensile elongation (D
E) is 15.5%, nodule strength (KT) is 2.72 g/d
The knot elongation (KE) was 11.3%, the knot strength/tensile strength ratio (KT/DT) was 0.91, and the pill resistance was grade 1, but the intrinsic viscosity after dyeing was 0.9%. 429, tensile strength (
DT) is 2.67g/d, tensile elongation (DE) is 12
．． 8%, knot strength (KT) is 1.38 g/d, knot elongation is 6.0%, knot strength/tensile strength ratio (KT/DT) is 0
．． 52, and the anti-building properties showed grade 4-5.

Example 2 Ethyl acid phosphate (mixture of monoethyl form and diethyl form) as a phosphorus compound has a concentration of 127 phosphorus atoms
The same procedure as in Example 1 was carried out except that 4ppa+/polymer was added, and the intrinsic viscosity was 0.573 and the residual phosphorus atom Ji was 10.
A polyester with a diethylene glycol content of 4.1 mol% was obtained. After reeling and spinning under the same conditions as in Example 1, a tubular knitted fabric was prepared and heated at 130°C.
The dye was dyed for 0 minutes.

The results are shown in Table 1, and the pill resistance could be improved without adversely affecting spinning, drawing, etc.

Example 3 A phosphorus-containing polyester obtained in the same manner as in Example 2 was used, and the winding speed during melt spinning was changed to 1800 m/min. Dyeing was carried out in four colors to examine anti-building properties, etc.

The results are shown in Table 1, and it was possible to improve the building resistance without causing any other problems.

Example 4 Using phosphorus-containing polyester obtained in the same manner as in Example 2, yarn reeling, spinning, tubular knitting and processing were carried out in the same manner as in Example 1, except that the winding speed during melt spinning was 1300 m for 7 minutes. Four-color dyeing was performed to examine anti-pilling properties, etc.

The results are shown in Table 1, and it was possible to improve the pill resistance without causing any other problems.

Example 5 A phosphorus-containing polyester obtained in the same manner as in Example 2 was melt-spun at a winding speed of 1800 m for 7 minutes.
Silk spinning was carried out in exactly the same manner as in Example 1 except that the heat treatment was carried out at ℃.
The anti-pilling properties were investigated by spinning, knitting, and dyeing.

The results are shown in Table 1, and the anti-pilling properties could be improved without any problems.

Example 6 A phosphorus-containing polyester obtained in the same manner as in Example 2 was melt-spun at a winding speed of 1800 m for 7 minutes.
The yarn spinning, spinning, tubular knitting, and dyeing in 5 colors were carried out in the same manner as in Example 1, except that heat treatment was performed at 5° C. for 0.8 seconds, and anti-pilling properties and the like were examined.

The results are shown in Table 1, and the anti-pilling properties could be improved without any problems.

Example 7 A phosphorus-containing polyester obtained in the same manner as in Example 2 was melt-spun at a winding speed of 1800 m for 7 minutes.
Thread spinning, spinning, tubular knitting, and dyeing in five colors were carried out in exactly the same manner as in Example 1, except that heat treatment was performed at 5° C. for 2.4 seconds, and anti-pilling properties etc. were investigated.

The results are shown in Table 1, and the anti-pilling properties could be improved without any problems.

Comparative Example 1 An experiment was conducted in exactly the same manner as in Example 1, except that the addition of the phosphorus compound was omitted.

The results are shown in Table 1, and although "brittleness" could be imparted by heat treatment, no improvement in anti-build property was observed because the fiber quality hardly changed before and after dyeing.

Comparative Example 2 A product was prepared in the same manner as in Example 1, except that ethyl diethyl phosphonoacetate was added as a phosphorus compound at 2350 ppm/polymer in terms of phosphorus atoms, and the intrinsic viscosity was 0.587.
A polyester having a phosphorus atom residual rit of 1400 ppm/polymer and a diethylene glycol content of 3.4 mol% was obtained. After spinning and spinning under the same conditions as in Example 1, a tubular knitted fabric was prepared, and then dyed in a rich color at 130° C. for 60 minutes.

The results are shown in Table 1, and the anti-pilling property improvement effect was hardly enhanced.

Comparative Example 3 Using phosphorus-containing polyester obtained in the same manner as in Example 1, an experiment was conducted in exactly the same manner as in Example 1, except that after melt spinning at a winding speed of 2500 m and 7 minutes, heat treatment was omitted. .

The results are shown in Table 1, and no anti-pilling property improvement effect was observed because the structural modification effect due to heat treatment was not expressed.

Comparative Example 4 Same as Example 1 except that trimethyl phosphate was added as a phosphorus compound at 600 ppm/polymer in terms of phosphorus atom, intrinsic viscosity 0.619, phosphorus atom content 490 ppm/polymer, diethylene glycol content 3.5 Mol% of polyester was obtained. Using this polyester, yarn was spun and spun under the same conditions as in Example 1, and then a tubular knitted fabric was made, which was dyed in a rich color at 130° C. for 60 minutes, and its performance was investigated.

The results are shown in Table 1, and since the hydrolysis rate was slow, the yarn properties could not be sufficiently reduced, and no anti-pilling property improvement effect was observed.

Comparative Example 5 As a phosphorus compound, ethyl acid phosphate (mixture of monoethyl form and diethyl form) was used as a phosphorus compound with a concentration of 18
The same procedure as in Example 1 was carried out except that 75 ppm/polymer was added, and the intrinsic viscosity was 0.542 and the residual phosphorus atom was 150.
0ppm/polymer, diethylene glycol content 5
．． 0 mol% polyester was obtained.

Melt spinning was attempted using this polyester at a winding speed of 1,300 m and 7 minutes, but winding was impossible due to frequent single yarn breakages.

Comparative Example 6 Using phosphorus-containing polyester obtained in the same manner as in Example 2, yarn spinning, spinning, and tubular knitting were carried out in the same manner as in Example 1, except that the winding speed during melt spinning was 64)0 m7 minutes. And anti-pilling properties etc. were investigated by dyeing in 5 colors.

The results are shown in Table 1, and the effect of improving the anti-build property was not found because the structural modification during spinning and winding was insufficient.

Comparative Example 7 An experiment was conducted in exactly the same manner as in Example 2, except that the heat treatment time was 0.3 seconds.

The results are shown in Table 1, and since the structural modification effect by heat treatment was insufficient, no anti-pilling property improvement effect was observed.

Comparative Example 8 An experiment was carried out in exactly the same manner as in Example 2, except that the heat treatment time was changed to 4.0 seconds.

The results are shown in Table 1, and the tensile strength before dyeing was too high, so the anti-build property improvement effect was not sufficient.

Comparative Example 9 An experiment was conducted in exactly the same manner as in Example 2, except that the heat treatment temperature was 180°C.

The results are shown in Table 1, and no anti-pilling property improving effect was observed because sufficient structural changes were not expressed.

[Effects of the Invention] The present invention is configured as described above, and by specifying the intrinsic viscosity of polyester Hm fibers containing phosphorus atoms and strictly specifying the ratio between knot strength and tensile strength, productivity, etc. It was possible to provide polyester TA fibers with excellent anti-build properties without causing any problems or adversely affecting other fiber properties.

Claims (1)

[Scope of Claims] (1) A polyester fiber made of a condensation polymer of a dicarboxylic acid mainly composed of terephthalic acid and an alkylene glycol mainly composed of ethylene glycol, which has an intrinsic viscosity of 0.36 to 0.46. Yes, contains a phosphorus atom, and
An anti-pilling polyester fiber characterized by satisfying the relationship of the following formula [I]. 0.3≦KT/DT≦0.85... [I] However, K
T means knot strength (g/denier) and DT means tensile strength (g/denier). (2) Phosphorus atom content is 700~ relative to polyester
The pill-resistant polyester fiber according to claim 1, which has a content of 1300 ppm. (3) The pill-resistant polyester fiber according to claim 1, wherein the polyester fiber satisfies the following formulas [II] and [III]. 2.0≦DT≦3.5...[II] 1.0≦KT≦2.5...[III] However, DT and KT have the same meaning as before.