JP2008169502A - Polyester fiber and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-toughness polyester fiber having good spinning conditions with high economical efficiency. <P>SOLUTION: The polyester fiber is composed of a polymer blend of 99.9-97.0 wt.% of a polyester (A) in which the main repeating unit is composed of ethylene terephthalate and 0.1-3.0 wt.% of an amorphous polymer having a glass transition temperature of 90-270°C or a crystalline polymer (B) having a glass transition temperature of 90°C or higher and a melting point of 275°C or higher. In the polyester fiber, the tensile strength is 0.5-3.5 cN/dtex and the tensile elongation is 5.0-40.0%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polyester fiber having low toughness, and more particularly to a polyester fiber having excellent anti-pilling property and fiber cutting property and good spinning tone without using extremely low molecular weight polyester.

  Fabrics made of polyester fibers have various excellent properties including mechanical properties, weather resistance and durability, and are therefore widely used for clothing. However, friction was caused during wearing or washing, and the fibers were pulled out of the fabric structure and further entangled to generate pills called pills, which greatly deteriorated the quality and appearance. This is because the fluff is drawn out from the fluff existing on the surface or from the woven or knitted fabric by the short fiber fluff on the surface being entangled, and the fluffs are entangled with each other. Synthetic fibers such as polyester and polyacryl, which have high strength and elongation, have been a problem.

  For the purpose of suppressing such pilling, a method of reducing the strength of the fiber by using polyester fibers having a low polymerization degree and promoting the falling of the generated pilling is known. The mechanism of this anti-pill property expression is that pills are once generated by abrasion on the surface of the woven or knitted fabric. However, since the fiber strength is low, the pills easily fall off, and the pills are repeatedly generated and dropped off.

  However, in order to obtain a fiber having sufficient anti-pilling property by such a method, the degree of polymerization of the polymer must be greatly reduced. For this reason, the spinnability is lowered in the spinning process and the yarn of the spun yarn in the spinning process. There are drawbacks such as frequent cuts. In order to maintain the spinnability, it is necessary to cool and solidify the polymer discharged from the nozzle as early as possible.However, since the cooling position is close to the position immediately below the base, the base surface is easy to cool, and the discharge hole Thread breakage due to clogging is likely to occur. Furthermore, it is difficult to uniformly distribute the polymer on the nozzle due to the low melt viscosity, and fineness variation among single yarns is likely to occur.

  A hollow polyester fiber obtained by polymer blending a homopolyester and a copolymerized polyester in a weight ratio of 20:80 to 80:20 is shown. However, since the other component occupies at least 20% by weight, there is a drawback that staining spots and high elongation spots are large (see, for example, Patent Document 1).

  In a polyester fiber mainly composed of an ethylene terephthalate unit, an anti-pillar fiber is shown that hydrolyzes the polyester by alkali treatment after spinning to lower toughness (see, for example, Patent Document 2). There are disadvantages such as an environmental problem due to the generation of the waste alkaline solution, and an increase in cost and lead time due to an increase in the number of processes for fabrics and applications that do not originally require alkali treatment.

JP 2003-13332 A JP-A-6-128815

  An object of the present invention is to provide a polyester fiber having good spinning tone, high economic efficiency, low toughness, and excellent anti-pill properties.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that 99.9 to 97.0% by weight of polyester (A) whose main repeating unit is ethylene terephthalate and a glass transition temperature of 90 to 270. A non-crystalline polymer having a glass transition temperature of 90 ° C. or higher and a melting point of 275 ° C. or lower. It was found that the problem is solved by a polyester fiber characterized by having a tensile elongation of 5.0 to 40.0% of 0.5 to 3.5 cN / dtex. (1) A step of melt-kneading polyester (A) and amorphous polymer or crystalline polymer (B) at a weight ratio of 99.9: 0.1 to 97.0: 3.0 to produce a polymer blend. (2) Step of cooling and solidifying the polymer blend discharged from the fiber spinning nozzle by a gas flow from downstream of the fiber spinning nozzle by 40 mm or more, and (3) The polymer blend discharged from the fiber spinning nozzle It has been found that the above-mentioned problems can be solved also by a process of taking a yarn at a spinning speed of 1500 m / min or less, further drawing and heat-treating.

  Since the present invention does not use a conventionally known low intrinsic viscosity polyester, it is less susceptible to polymer distribution spots due to a decrease in melt viscosity and cooling of the die surface due to quench spinning, and has a very low spinning toughness fiber. Can be obtained. Further, unlike sulfoisophthalic acid copolymerized polyethylene terephthalate, cracks do not occur in the undrawn yarn due to changes over time at high temperatures, and there is no need for temperature control. Furthermore, it is possible to set the toughness of the fiber, that is, the high elongation property, to a desired value by changing the amount of the high glass transition point resin added.

  The fiber of the present invention can be used as a main component, in particular, polyethylene terephthalate having a general-purpose intrinsic viscosity, and as a main fiber in producing a molded molded fiber structure as well as an anti-pilling fiber, it can be cut. It is possible to provide an excellent polyester fiber.

Hereinafter, embodiments of the present invention will be described in detail.
The polymer constituting the polyester fiber of the present invention is an amorphous polymer or glass having 99.9 to 97.0% by weight of polyester (A) whose main repeating unit is ethylene terephthalate and a glass transition temperature of 90 to 270 ° C. It is in the form of a polymer blend of 0.1 to 3.0% by weight of a crystalline polymer (B) having a transition temperature of 90 ° C. or higher and a melting point of 275 ° C. or lower. Here, “main” means that the ethylene terephthalate repeating units occupy 70 mol% or more based on all repeating units in the polyester.

  Typical polyesters constituting the polyester (A) include polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN). The polyester used as the polyester (A) of the invention is preferably a polyester whose main repeating unit is alkylene terephthalate in terms of strong elongation characteristics and rigidity, and most preferably polyethylene terephthalate. In this polyethylene terephthalate, a dicarboxylic acid other than terephthalic acid (for example, phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethane) is used in accordance with the purpose within a range not impairing the high elongation property of the present invention. Aromatic dicarboxylic acids such as dicarboxylic acids, 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 4-sodium sulfo-2,6-naphthalenedicarboxylic acid, 2-sodium sulfoterephthalic acid, 2-potassium sulfoterephthalic acid, etc. Aromatic dicarboxylic acids containing a metal sulfonate group, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, decanedicarboxylic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid) and diol components other than ethylene glycol (eg , Aliphatic diols such as diethylene glycol, trimethylene glycol, propylene glycol, tetramethylene glycol, neopentyl glycol, hexanemethylene glycol, dodecamethylene glycol, alicyclic glycols such as cyclohexanedimethanol, bisphenol A, bisphenol F, bisphenol S, It may be a copolyester obtained by copolymerizing hydroquinone, aromatic diols such as 2,2-bis (4-β-hydroxyethoxyphenyl) propane). Further, a small amount of a polyfunctional compound such as trimesic acid, trimellitic acid, pyromellitic acid, trimethylolethane, trimethylolpropane, trimethylolmethane, pentaerythritol may be copolymerized.

  As the polyester (A), one having an intrinsic viscosity of 0.55 to 0.70 dL / g is preferably used. When the intrinsic viscosity is less than 0.55 dL / g, the polymer has a remarkably low melt viscosity like the conventional anti-pill fiber, so it is necessary to cool directly under the die surface. Yarns tend to occur frequently. Furthermore, when the polymer (B) of the present invention is added, the strength of the fabric itself is remarkably lowered due to excessively low toughness, which causes problems in handling properties and washing durability. On the other hand, when the intrinsic viscosity exceeds 0.70 dL / g, the toughness exceeds the range suitable for the anti-pill property, and thus the anti-pill performance which is the object of the present invention cannot be obtained. A more preferred range is 0.57 to 0.68 dL / g.

  The polymer (B) is selected from an amorphous polymer having a glass transition temperature (Tg) of 90 to 270 ° C or a crystalline polymer having a glass transition temperature of 90 ° C or higher and a melting point (Tm) of 275 ° C or lower. Preferably, it can be adopted from linear thermoplastic polymers, and may be an addition polymerization polymer or a polycondensation polymer as long as it satisfies the above-mentioned requirements of Tg and Tm. . The amorphous polymer is preferably a polymer having a Tg of 100 to 250 ° C, and the crystalline polymer is preferably a polymer having a glass transition temperature of 100 ° C or higher and a melting point of 180 to 270 ° C. Typical polymer examples are polystyrene (Tg = about 100 ° C.), polymethyl methacrylate (Tg = about 115 ° C.), and bisphenol A polycarbonate (Tg = about 150 ° C., Tm = about 267 ° C.). Among them, syndiotactic polystyrene has a high melting point such as Tg = 100 ° C. and Tm = 270 ° C., and has a great toughness reducing effect. Here, “bisphenol A polycarbonate” refers to a polycarbonate obtained by reacting bisphenol A (2,2-bis (4-hydroxyphenyl) propane) with a carbonic acid bond forming compound (for example, phosgene, diphenyl carbonate, dialkyl carbonate).

  The amount of the polymer (B) added is limited to 0.1 to 3.0% by weight. If it is less than 0.1% by weight, the toughness-reducing effect that is the object of the present invention is not observed. On the other hand, if it exceeds 3.0% by weight, the toughness of the undrawn yarn will be too low, and if the amount added is further increased, the blended state will become non-uniform, the spinnability will become extremely poor, and spinning will be impossible. A preferable range is 0.3 to 2.5% by weight, and a more preferable range is 0.5 to 2.0% by weight. The fiber of the present invention is characterized in that the toughness can be adjusted by changing the amount of the polymer (B) added. Depending on the composition of the polyester (A) and the intrinsic viscosity, the desired high elongation physical property can be obtained. In order to adjust, the kind and addition amount of polymer (B) can be adjusted.

  Furthermore, in order to exhibit a toughness lowering effect, it is preferable that the melt flow rate (MFR) of the polymer (B) is limited to a range of 0.1 to 1.5 g / 10 min. If the MFR exceeds 1.5 g / 10 min, the toughness tends to be too large, which is not preferable. When the MFR is less than 0.1 g / 10 min, the melt viscosity of the polymer discharged from the nozzle is excessively increased, causing melt fracture and inferior spinnability. A preferable range is 0.2 to 1.3 g / 10 min.

  As a method for preparing a polymer blend of polyester (A) and polymer (B), the pellets of both polymers are preliminarily mixed with a batch mixing device such as a Nauta mixer or a double cone blender, that is, the polyester of the present invention is mixed. In the case of production, a method of blending at a weight ratio of 99.9: 0.1 to 97.0: 3.0, and melt-kneading with a melt extruder (extruder), a predetermined mixing ratio of each pellet A method of continuously feeding to an extruder and melt-kneading with separate weighing machines so as to become, or a method of kneading separately melted polyester (A) and polymer (B) at the above-mentioned weight mixing ratio through a multistage static mixer, etc. Can be melt-kneaded. As the extruder, the 2-axis extruder is superior to the 1-axis extruder in terms of kneadability. However, when (A) and (B) are supplied from separate weighing machines, the 2-axis extruder is used. Is preferred. Polyester pellets need to be dried with vacuum drying, heated nitrogen or dehumidified air in order to suppress molecular weight reduction due to hydrolysis, but in the case where a degassing device (vent device) is installed in the extruder The pellets may be supplied without drying. In addition, the pellets may be dried by a method of drying the mixed pellets or a method of mixing separately dried pellets after drying.

The above-mentioned polymer blend is in a state where both polymers are melted, preferably as a molten polymer blend of 280 ° C. or higher, and is discharged from a known fiber spinning nozzle, and air-cooled by a gas flow from a downstream point of 40 mm or more from the nozzle, preferably Is taken at a spinning speed of 1500 m / min or less while cooling and solidifying from a point downstream of 40 to 100 mm from the nozzle to obtain an undrawn yarn. Next, the polyester fiber of the present invention can be obtained through a step of subjecting the obtained undrawn yarn to a conventionally known drawing treatment and then a heat treatment. The gas flow can be arbitrarily selected from air, nitrogen, and other ordinary gases, but it is most convenient and preferable to use air. The temperature of the gas is not particularly limited as long as it is 50 ° C. or more lower than the discharged polymer, and is 20 ° C. or higher, and more preferably 50 ° C. or lower than the discharged polymer temperature. The flow rate is particularly preferably 0.5 Nm ³ / min or more from the viewpoint of cooling efficiency.

  When air is cooled by a gas flow from a point less than 40 mm from the nozzle, the cooling position is close to the position immediately below the base, so that the base surface is likely to be cooled, and as a result, yarn breakage is likely to occur due to clogging of the discharge holes. It is not preferable. On the other hand, when the take-up speed exceeds 1500 m / min, fibers having excellent anti-pill properties may not be obtained, which is not preferable.

  The stretching conditions may be cold stretching or heating and heating with warm water, oil bath, steam, heater, etc., but in order to reduce the heat shrinkage rate, the tension heat treatment at 1.05 times or less or between rollers It is necessary to perform a relaxation heat treatment in the state of overfeeding and complete tension free. After stretching, after applying a necessary oil according to the application, mechanical crimping is applied with a crimper, and after drying, it is cut into a desired fiber length. Moreover, when it is not necessary to give crimp according to a use, it is not necessary to use a crimper.

  By adopting these production conditions, a thermoadhesive conjugate fiber having a tensile strength of 0.5 to 3.5 cN / dtex and a tensile elongation of 5.0 to 40.0% can be obtained. Can be solved.

  The mechanism by which the toughness is lowered by the polymer blend of the polyester (A) and the polymer (B) as in the present invention is not clear, but is estimated as follows. Since the polymer (B) has a Tg higher than that of the polyester (A), after being discharged from the nozzle, the polymer (B) is solidified before the polyester (A) to suppress the orientation of the polyester (A). Therefore, if the spinning speed is relatively low of 1500 m / min or less, the orientation of the polyester (A) is relatively loose. As a result, the polyester having a low intrinsic viscosity is rapidly cooled at an early timing after discharging, and the solidification point is set. It will be similar to the structure brought upstream. Unlike polyester with a low intrinsic viscosity, it is not necessary to cool directly under the die, so that the possibility of thread breakage due to clogging of the polymer is reduced and the spinning condition is good. Furthermore, if the polymer (B) becomes a high melting point crystalline component such as syndiotactic polystyrene or a high melting point polymer having a low MFR, coupled with the effect of increasing the solidification point of the polyester (A), It is considered that the polymer (B) dispersed in the island state in the fiber becomes a mechanical defect, and when a tensile force is generated, stress is concentrated on the island component and promotes low toughness.

  By using the above-described polyester fiber of the present invention and the production method thereof, the polyester fiber having a tensile strength of 0.5 to 3.5 cN / dtex and a tensile elongation of 5.0 to 40.0%, Preferably, a polyester fiber having a low toughness (silk factor) of 20 or less and excellent in anti-pilling property and cutting property can be obtained.

  Depending on the purpose, these fibers contain small amounts of additives such as matting agents, lubricants, flame retardants, antistatic agents, pigments, dyes, antioxidants, light stabilizers, heat stabilizers, compatibilizers, fluorescent agents. It may contain a brightener, an antibacterial agent, an ultraviolet absorber and the like.

In addition, the cross-sectional shape of the fiber is not particularly limited, and may be solid or hollow, and depending on the purpose, in addition to a round cross section, a triangular cross section, a square cross section, a flat cross section, a cross section It may have an irregular cross section such as a multi-leaf cross section such as H-shape or W-shape.
The single yarn fineness is not particularly limited, and is suitable as a thick fineness application having relatively poor anti-pill properties and cutting properties. A preferable range is 0.1 to 200 dtex.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. In addition, each item in an Example was measured with the following method.
(1) Intrinsic viscosity (IV)
A certain amount of the polyester polymer was weighed and dissolved in o-chlorophenol at a concentration of 0.012 g / mL, and then determined at 35 ° C. according to a conventional method.
(2) Melt flow rate (MFR)
The polymethyl methacrylate resin was measured according to JIS-K7210 condition 15 (230 ° C., 37.26 N), and the other resins were measured according to JIS-K7210 condition 21 (300 ° C., 11.77 N). The melt flow rate is a value measured using a pellet before melt spinning as a sample.
(3) Melting point (Tm), glass transition point (Tg)
A thermal analyst 2200 manufactured by TA Instrument Japan Co., Ltd. was used, and the temperature was measured at a temperature rising rate of 20 ° C./min.
(4) Fineness Measured by the method described in JIS L 1015: 2005 8.5.1 Method A.
(5) Tensile strength (Te) / Tensile elongation (El)
It was measured by the method described in JIS L 1015: 2005 8.7.1 method.
(6) Silk factor (Sf)
From the measured tensile strength (Te) and tensile elongation (El), the following formula is used.
Silk factor and toughness are agreed.
Sf = Te (cN / dtex) × √ {El (%)}
(7) Crimp number (CN), crimp rate (CD)
It was measured by the method described in JIS L 1015: 2005 8.12.1 to 8.12.3.
(8) Dry heat shrinkage rate Measured at 180 ° C. in JIS L 1015: 2005 8.15 b). (9) Anti-pill property After forming a spun yarn consisting of 100% short fibers cut to a fiber length of 64 mm, a plain woven fabric was prepared using the spun yarn and evaluated by the method described in JIS L 1076: 1992 A method. The higher the grade, the less the pill and the better.

[Example 1]
As polymer (A), IV = 0.64 dL / g, Tg = 70 ° C., 98 parts by weight of polyethylene terephthalate (PET) with Tm = 256 ° C., and as polymer (B), MFR = 3 g / 10 min, Tg = 100 ° C. After mixing both types of pellets to 2 parts by weight of syndiotactic polystyrene (XAREC F2907 (trade name), hereinafter abbreviated as SPS, manufactured by Idemitsu Petrochemical Co., Ltd.) at Tm = 270 ° C., 1 hour at 80 ° C., Dry under reduced air at 170 ° C. for 4 hours, melt and knead with a single screw extruder to obtain a polymer blend at 280 ° C. From a spinneret having a round hole nozzle with a hole diameter of 0.4 mm and a hole number of 240 It was discharged at a discharge rate of 220 g / min, and an undrawn yarn was obtained at a spinning speed of 1050 m / min. At this time, 1.7 Nm ³ / min of cooling air (25 ° C., 60% RH) was applied 50 mm downstream of the base to solidify the polymer blend. The resulting undrawn yarn is focused on a tow of about 500,000 dtex, stretched 2.5 times in warm water at 70 ° C, and then double-stretched 1.2 times in warm water at 90 ° C. After immersing the yarn in an aqueous solution of a surfactant composed of phosphate potassium salt / polyethylene glycol laurate = 50/50, it was subjected to mechanical crimping of 11 pieces / 25 mm using an indentation type crimper and dried at 135 ° C. Thereafter, the fiber length was cut to 64 mm. At this time, the single yarn fineness is 3.3 dtex, the strength is 2.5 cN / dtex, the elongation is 21.0%, the silk factor is 11.5, CN = 11.2 mountain / 25 mm, CD = 16.0%, dry heat shrinkage The rate was 6%. The anti-pill properties of this fiber are shown in Table 1.

[Example 2]
The procedure was the same as Example 1 except that the amount of SPS added was 0.2 parts by weight. The results are shown in Table 1.

[Example 3]
The procedure was the same as Example 1 except that the amount of SPS added was 1 part by weight. The results are shown in Table 1.

[Comparative Example 1]
The procedure was the same as Example 1 except that the amount of SPS added was 4 parts by weight, but there was a tendency to break the yarn unless the spinning speed was reduced to 600 m / min. The undrawn yarn obtained at a spinning speed of 600 m / min was not drawn into a neck shape even when pulled, and was weak enough to be cut immediately.

[Comparative Example 2]
Polyethylene terephthalate (PET) with IV = 0.64 dL / g, Tg = 70 ° C., Tm = 256 ° C. was dried in dehumidified air at 80 ° C. for 1 hour and 170 ° C. for 4 hours, and then melted with a uniaxial extruder. A melt at 290 ° C. was discharged at a discharge rate of 270 g / min from a spinneret having a round hole nozzle with a hole diameter of 0.4 mm and a hole number of 240, and an undrawn yarn was obtained at a spinning speed of 1050 m / min. . At this time, a cooling air (25 ° C., 60% RH) of 1.7 Nm ³ / min was applied 56 mm downstream of the base to solidify the polymer blend. The resulting undrawn yarn is focused on a tow of about 500,000 dtex, stretched 3.5 times in warm water at 70 ° C, and then double-stretched 1.05 times in warm water at 90 ° C. After immersing the yarn in an aqueous solution of a surfactant composed of phosphate potassium salt / polyethylene glycol laurate = 50/50, it was subjected to mechanical crimping of 11 pieces / 25 mm using an indentation type crimper and dried at 135 ° C. Thereafter, the fiber length was cut to 64 mm. Single yarn fineness at this time is 3.3 dtex, strength is 4.4 cN / dtex, elongation is 42.2%, silk factor is 28.5, CN = 10.8 mountain / 25 mm, CD = 14.8%, dry heat shrinkage. The rate was 5.0%. The anti-pill properties of this fiber are shown in Table 1.

[Reference Example 1]
Polyethylene terephthalate (PET) with IV = 0.43 dL / g, Tg = 70 ° C., Tm = 256 ° C. was dried in dehumidified air at 80 ° C. for 1 hour and 170 ° C. for 4 hours, and then melted with a uniaxial extruder. Thus, a melt at 272 ° C. was discharged at a discharge rate of 290 g / min from a spinneret having a round hole nozzle having a hole diameter of 0.4 mm and a hole number of 240, and an undrawn yarn was obtained at a spinning speed of 1200 m / min. . At this time, a cooling air (25 ° C., 60% RH) of 1.8 Nm ³ / min was applied 17 mm downstream of the die to solidify the polymer blend. The resulting undrawn yarn was focused on a tow of about 500,000 dtex, drawn 3.5 times in warm water at 68 ° C, and then double-stretched 1.0 times in warm water at 90 ° C. After immersing the yarn in an aqueous solution of a surfactant composed of phosphate potassium salt / polyethylene glycol laurate = 50/50, 11 crimps / 25 mm of mechanical crimps were applied using an indentation type crimper and dried at 130 ° C. Thereafter, the fiber length was cut to 64 mm. The single yarn fineness is 3.3 dtex, the strength is 3.2 cN / dtex, the elongation is 39.0%, the silk factor is 20.0, CN = 10.5 peak / 25 mm, CD = 16.0%, and dry heat shrinkage. The rate was 2.1%. The anti-pill properties of this fiber are shown in Table 1.
In the fiber production process, there were many yarn breaks at the start of the spinning process, and there were many yarn breaks even in a stable and steady state.

[Reference Example 2]
Polyethylene terephthalate (PET) with IV = 0.37 dL / g, Tg = 70 ° C., Tm = 256 ° C. was dried in dehumidified air at 80 ° C. for 1 hour and 170 ° C. for 4 hours, and then melted with a uniaxial extruder. A melt of 270 ° C. was discharged from a spinneret having a hole diameter of 0.4 mm and a round hole nozzle having a hole number of 240 at a discharge rate of 270 g / min, and an undrawn yarn was obtained at a spinning speed of 1050 m / min. . At this time, 1.5 Nm ³ / min cooling air (25 ° C., 60% RH) was applied 17 mm downstream of the die to solidify the polymer blend. The obtained undrawn yarn was focused on a tow of about 500,000 dtex, drawn 3.4 times in warm water at 68 ° C., and then double-stretched 1.05 times in warm water at 80 ° C. to obtain lauryl. After immersing the yarn in an aqueous solution of a surfactant composed of phosphate potassium salt / polyethylene glycol laurate = 50/50, 11 crimps / 25 mm of mechanical crimps were applied using an indentation type crimper and dried at 130 ° C. Thereafter, the fiber length was cut to 64 mm. At this time, the single yarn fineness is 3.3 dtex, the strength is 2.9 cN / dtex, the elongation is 36.1%, the silk factor is 17.4, CN = 10.6 mountain / 25 mm, CD = 15.8%, dry heat shrinkage The rate was 1.1%. The anti-pill properties of this fiber are shown in Table 1.
In the fiber production process, there were many yarn breaks at the start of the spinning process, and there were many yarn breaks even in a stable and steady state.

[Example 4]
The polymer (B) was Tg = 105 ° C. and MFR = 1.8 polymethyl methacrylate (Amirex CM-205 (trade name) manufactured by Kyami Real Co., Ltd .; hereinafter abbreviated as PMMA), The same operation as in Example 1 was performed. The results are shown in Table 1.

[Example 5]
Except that the polymer (B) was polybisphenol A carbonate (Terit Kasei Co., Ltd. Panlite K-1300Y (trade name); hereinafter abbreviated as PBAC) with Tg = 140 ° C. and MFR = 2.5 g / 10 min. 1 was performed. The results are shown in Table 1.

  As described above, according to the present invention, it is possible to supply an anti-pill fiber having good productivity and low cost for garments by utilizing a general-purpose intrinsic viscosity polyethylene terephthalate. Furthermore, it is particularly suitable as a main fiber because it has a very good cutting property in applications that require cutting of the web before and after shaping processing such as sound absorbing materials for automobiles and building materials, food packaging materials, filters, sanitary materials, etc. Provide polyester fiber.

Claims (9)

  99.9 to 97.0% by weight of polyester (A) whose main repeating unit is ethylene terephthalate, an amorphous polymer having a glass transition temperature of 90 to 270 ° C. or a glass transition temperature of 90 ° C. or higher and a melting point of 275 ° C. It is a polyester fiber comprising a polymer blend of 0.1 to 3.0% by weight of a crystalline polymer (B) which has the following tensile strength of 0.5 to 3.5 cN / dtex and tensile elongation of 5.0 to 40 Polyester fiber characterized by being 0.0%.   The polyester fiber according to claim 1, wherein the polyester (A) is polyethylene terephthalate.   The polyester fiber according to claim 1 or 2, wherein the intrinsic viscosity of the polyester (A) is 0.55 to 0.70 dL / g.   The polyester fiber according to any one of claims 1 to 3, wherein the melt flow rate of the polymer (B) is 0.1 to 5.0 g / 10 min.   The polyester fiber according to any one of claims 1 to 4, wherein the polymer (B) is polystyrene.   The polyester fiber according to claim 5, wherein the polymer (B) is syndiotactic polystyrene.   The polyester fiber according to any one of claims 1 to 4, wherein the polymer (B) is polymethyl methacrylate.   The polyester fiber according to any one of claims 1 to 4, wherein the polymer (B) is bisphenol A polycarbonate. The manufacturing method of the polyester fiber of any one of Claims 1-8 characterized by including the process of following (1)-(3).
(1) A step of melt-kneading polyester (A) and amorphous polymer or crystalline polymer (B) at a weight ratio of 99.9: 0.1 to 97.0: 3.0 to produce a polymer blend ( 2) Step of cooling and solidifying the polymer blend discharged from the fiber spinning nozzle by a gas flow from the downstream side of the fiber spinning nozzle by 40 mm or more. (3) The polymer blend discharged from the fiber spinning nozzle. A process of drawing at a spinning speed of 1500 m / min or less, further drawing and heat treatment