JPS6197420A - Antipilling easily-dyeable polyester fiber - Google Patents

Abstract

PURPOSE:To provide the titled fiber having excellent dyeability and light resistance, and giving a fluffed cloth having excellent cuttability, antipilling property, resistance to falling and flattening of the fluff, and covering property, by forming a specific copolymerized polyester to a fiber having specific cross-sectional shape. CONSTITUTION:A fiber of a copolymerized polyester having an intrinsic viscosity of >=0.3 and composed of the recurring unit of formula I or formula II [R is dicarboxylic acid residue (>=80 mol% thereof is terephthalic acid residue); R1 is glycol residue; R2 is (CiH2iO)m-R3-(CjH2jO)n; R3 is 4-20C bivalent aliphatic hydrocarbon group; m and n are integer; 3<=m+n<=10; i and j are integer of 2-4; the glycol component of formula (R2-O) accounts for 1-10 wt% of the produced polyester]. The ration of the minimum value to the maximum value of the secondary moment of the cross-section is 1/2-1/20, and the ratio of the secondary moment of the cross-section of a circle having the same cross-sectional area to the minimum secondary moment of the cross-section is <=5/1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a pill-resistant and easily dyeable polyester fiber suitable for use as a raised blanket.

(Prior art) Acrylic fibers have been widely used as fibers for napping blankets, but acrylic fibers have problems such as anti-pilling properties, low straightness of napping, and high tendency to set. The problem has been dealt with by increasing the basis weight, but it has not yet been solved satisfactorily. On the other hand, aromatic polyesters represented by polyethylene terephthalate 1- have improved η hair uprightness and set resistance compared to the acrylic fibers described in There is a problem. Regarding the ease of dyeing of polyester fibers, polyester copolymerized with a compound such as 5-1 helium sulfoisophthalate can be dyed with basic dyes or disperse dyes without a carrier at normal pressure, I O (around 1°C). Dyeing has been proposed, but since 5-sodium sulfoisophthalic acid is contained in an amount greater than 5 mol% of the polyester acid component, operability in the yarn spinning process is extremely poor, and the hydrolysis resistance of the product is also poor. It is difficult to put it into practical use because it deteriorates.

It is also known that by using a copolymerized ester obtained by copolymerizing polyester with a high molecular weight polyoxyethylene glycol or its homolog having a molecular weight of 200 or more, an effect of easy dyeing can be obtained without significantly lowering the melting point of the polyester. However, this copolymerized ester fiber has extremely poor light fastness of the dyed product, poor mechanical properties, and especially large set-up of the nap. In addition, various polyester fibers made of copolymers of various aromatic dicarboxylic acids or their alkyl esters, and copolymers of various glycols have been proposed as materials that reduce the decrease in light resistance and provide easy dyeability. However, in order to obtain sufficient dyeability, it is necessary to lower the melting point of the polyester, resulting in a decrease in mechanical properties and a problem in durability.

Previously, the applicant proposed a copolyester that has excellent mechanical properties and satisfies dyeability and light resistance (see Japanese Patent Laid-Open No. 57-63325).

On the other hand, many methods are known in which low-viscosity polymers are used to impart pilling properties to polyester fibers (Japanese Patent Publication No. 35-8562, Japanese Patent Application Laid-Open No. 49-2651).
(See Publication No. 6, Special Publication No. 51-43089, etc.)
Since these methods use low viscosity polymers, strength or knot strength is reduced, operability in the spinning and post-processing steps is significantly reduced, and costs are high. Also, a method for producing pile-pilling polyester fiber using a high viscosity polymer (Japanese Patent Publication No. 47-9854, Japanese Patent Application Laid-Open No. 52-148)
221) has been proposed, but sufficient anti-building properties cannot be obtained.

This applicant has proposed that the moment of inertia T
We proposed a pile-pillar polyester fiber with a ratio of the moment of inertia Ty to the axis perpendicular to the X-axis (y-axis) (Iy/Ix) of 0.8 or less, and a torsion in the fiber axis ( (Japanese Patent Application No. 59-29359).

(Problems to be Solved by the Invention) =4- The fiber obtained from the copolyester described in JP-A No. 57-63325 has anti-pilling property of the raised cloth, uprightness of the raised cloth, covering property, It has problems such as poor cuttability during processing and lack of animal hair texture.

(Means for Solving the Problems) The present invention provides the following features:
This is a polyester fiber applied to the modified cross-section fiber described in the specification of No. 5.

In other words, the present invention provides a general formula (where R is a dicarboxylic acid residue and at least 80
Mol% is terephthalic acid residue. , R1 is a glycol residue and represents at least 80 mol% of the total glycol component.
is ethylene glycol, tetramethylene glycol, 1
, 4-cyclohexane dimetatool. R7 is (-CjiT, i0→]11R
:+-0 (=8.H,,10→1), R, is a divalent aliphatic hydrocarbon group having 4 to 20 carbon atoms, m and n are the same or different integers, and 3≦m+n ≦10, j, j are the same or different 2 to 4 integers, (-R, -0→-
The glycol component represented by occupies 1 to 10% by weight of the produced polyester) is composed of a copolymerized polyester having a limiting viscosity of 0.3 to 1. The moment of inertia of area I (Tmin) where the moment of inertia of area is the minimum and the moment of inertia of area i ~ (I
max) and the ratio ([min/Tmax) is 1/2-
]/20, and the ratio of the moment of inertia of the circular section with the same cross-sectional area 1~('Icj) to the minimum moment of inertia of the section (Tmi) written in - (Tc, ]711m
It is a pile-pilling, easily dyeable polyester fiber characterized in that 1n is 571 or less.

The copolymerized polyester forming the polyester fiber of this invention is composed of repeating m-positions represented by -1 formula (1) and (IT), and among the dicarboxylic acid residues R in formulas (1) and (n), At least 80 mole percent is derived from terephthalic acid or its ester-forming derivatives. 20
Less than mol% of other dicarboxylic acid residues may be aromatic dicarboxylic acids such as 5-metal sulfoisophthalic acid, isophthalic acid, naphthalene dicarboxylic acid, or their ester-forming derivatives, glital, to the extent that the quality of the copolymerized polyester is not deteriorated. Acids, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, and sepatic acid or ester-forming derivatives thereof, oxycarboxylic acids such as p-(2-hydroxyethoxy)benzoic acid or ester-forming derivatives thereof, and the like. In particular, when the content of 5-metal sulfoisophthalic acid residues is 0.5 to 5.0 mol%, preferably 1.0 to 3.5 mol%, dyeability with basic dyes and disperse dyes is significantly improved. The metal of sulfoisophthalic acid can form a salt with a sulfonic group, and specific examples include sodium, potassium, lithium, calcium, barium, lead, and lanthanum.

Among these, sodium is particularly preferred. The ester-forming derivatives of the above-mentioned dicarboxylic acids or oxycarboxylic acids are generally esters with lower alcohols such as methanol and ethanol, but may also be esters with glycols such as ethylene glycol.

At least 80 mol% of the glycol residue R1 in formula (1) of the repeating unit is one or more selected from ethylene glycol, tetramethylene glycol, and 1,4-cyclohexane dimetatool. Glycols are common. R7 in formula (n) is (-cl(z j
OhatRyo0 +C,iH,, ] Opan1,
R3 is a divalent aliphatic hydrocarbon group having 4 to 20 carbon atoms, specifically +CH, +-E, +CI] f) T,
, linear aliphatic hydrocarbon groups such as , aliphatic hydrocarbon groups having side chains such as □□□-1-CH, →-CH, -1
-Cjh-CR2[phase]-CH2tl.

Examples include hydrocarbon groups having an aliphatic ring such as, among them, an aliphatic hydrocarbon group having a side chain is preferred, and a tylpropylene group is most preferred.

Glycol residue + C1T (210±
i and j of j1 and fcjH2j are the same or different integers of 2 to 4. m and n are the same or different integers and are in the range of 3≦m+n≦10, preferably 3≦m+n≦8, more preferably 3≦m+
n≦6. Since the glycol component mentioned in item 1 is not distilled out during the polycondensation reaction when obtaining the copolymerized polyester, the content in the produced polyester is controlled to be constant and the quality is stable. Furthermore, the obtained copolymerized polyester has extremely high dyeability and exhibits excellent light fastness of dyed products that could not be obtained when high molecular weight polyethylene glycol was used as a copolymerization component. Additionally, polyester has the advantage that its melting point is much lower than when neopentyl glycol or diethylene glycol is used.

In the formula (If) of ``-'', when m and n are both O, or when m + n < 3, the problem of distillation in the polycondensation reaction of the glycol component of ``1'' and the copolymerized polyester The problem of lowering the melting point occurs. Also m +
When n > 10, the light fastness of the dyed product decreases significantly,
Lacks practicality.

The glycols represented by 17) HO-R, -OH in the formula (n) can be synthesized by adding ethylene oxide to the glycols represented by N0-R3-OH, respectively, by a conventional method. Incidentally, other alkylene oxides such as propylene oxide may be used in combination without impairing the effects of the present invention.

Furthermore, as long as the effects of this invention are not impaired, (
II) A glycol component represented by the formula m 10n > LO may be included, and in addition to the glycol represented by HO-R, -0f, a small amount of diethylene glycol,
Triethylene glycol, propylene glycol, 1,
4-bis(β-hydroxyethoxy)benzene, bisphenol A, bis-ethoxylated 2,2-bis(2,5
-dimethyl-4-hydroxyphenyl)propane, diphenylsilanol, and the like can be used. In addition, even if a branching agent such as pentaerythrol or pyromellitic acid is copolymerized to an extent that does not impair the fiber formability of the polyester, the +R2-0+ component shown in the above formula (n) is 1-10% by weight, preferably 2-8% by weight. If it is less than 1% by weight, the riding effect will decrease,
If it exceeds 10% by weight, the operability during spinning will be lowered, the melting point of the polyester will be lowered, and the light resistance and hydrolysis resistance will be lowered.

The above-mentioned copolymerized polyester can be obtained according to ordinary polyester manufacturing methods such as a method in which a dicarboxylic acid ester and a glycol are transesterified and then subjected to a polycondensation reaction, and a method in which a dicarboxylic acid and a glycol are esterified and then subjected to a polycondensation reaction. However, when producing polyester through an esterification reaction, adding the glycol represented by HO-R2-OH between just before the end of the esterification reaction and the start of the polycondensation reaction suppresses the decomposition of the ester bond. It is particularly preferable.

In addition, when using terephthalic acid or its ester-forming derivative and 5-metal sulfoisophthalic acid or its ester-forming derivative as the dicarboxylic acid, they may be reacted simultaneously, or these dicarboxylic acid components may be reacted separately. It is also possible to react with the glycol component and then mix the two in the polycondensation reaction stage. Examples of catalysts that promote these reactions include compounds of metals such as sodium, magnesium, calcium, zinc, manganese, soot, tungsten, germanium, titanium, and antimony.

The copolyester obtained by the above method has a melting point of 160 to 295° C. as measured by differential scanning calorimetry, and an intrinsic viscosity of 0.30 or more, preferably 0.40 or more. If the intrinsic viscosity is less than 0.30, the melt viscosity will be low, resulting in poor spinning operability due to yarn breakage during spinning, poor yarn strength, frequent yarn breakage during drawing, and the possibility of making the drawn yarn into a fabric. In this case, it becomes a practical problem in terms of fabric strength. Furthermore, the upper limit of the intrinsic viscosity is usually 0.0 from the viewpoint of fiber forming properties.
It is about 5 to 0.8.

The cross-sectional shape of the polyester fiber of this invention has a moment of inertia (Tmj
The ratio (Tmin/Iman
) is 172 to l/20, and the ratio of the moment of inertia of a circular section (Ici) with the same cross-sectional area to the minimum moment of inertia (Tmjn) (Ici/Imj
n) is 5/1 or less.

The above-mentioned fiber cross-sectional moment of inertia is defined by Kame Yuasa, [Mechanics of Materials] Volume 1, published by Corona Publishing, November 28, 1950, Volume 1.
This value was determined by the method shown on pages 20-123.

In other words, the cross-sectional photograph of the fiber is enlarged approximately 10,000 times,
Using this enlarged view, the moment of inertia of area lll1ax in the direction in which the moment of inertia of area is maximum is determined by the illustrative method (1) of the moment of inertia of area described in the above-mentioned literature, and the direction in which the above Tmax is determined is determined one after another. The moment of inertia of area in the cross-sectional direction (moment of inertia when the figure for which m ax was calculated is rotated 90 degrees) is lm1n, and the ratio of the moment of inertia of area 1- written by -1 is Tmj n /
I'max is 1/2~]/20, preferably 173~1
/15, more preferably 175 to 1/10, and - ]21 circular cross-sectional moment of inertia 1-Tcj which is the same as the fiber cross-sectional area, and "minimum cross-sectional moment of inertia l
- The ratio Tcj /rmin with uljn is 571 or less,
It is preferably 271 or less, more preferably 171 or less, and the lower limit is 1/2.

-1- If Tm1n/Tma exceeds 1/2, the animal hair-like texture and anti-pilling properties will be poor, and the cuttability will also be reduced. On the other hand, if rmin/Tmax is less than 1/20, it will tend to bend in a specific direction, the uprightness of the raised hair will decrease, it will easily become flattened, and it will lack elasticity. Above Tci/Tm
When 1n exceeds 5/1, the uprightness of the raised hairs decreases, they tend to flatten, and they lack elasticity. Moreover, if Tcj/Tmjn is smaller than the lower limit value 1/2, the cross-sectional shape will be significantly deformed, causing problems in the production of spinning holes in the nozzle, and furthermore, the strength of the yarn will decrease, which is undesirable.

The shape of the spinning hole forming the above cross-sectional shape is square, X-
Examples include X type, IJ type, and N type.

In order to produce the polyester fiber of the present invention, a nozzle having a spinning hole that forms the fiber cross-sectional shape is used, and the other conditions are under normal spinning conditions, for example, at a spinning temperature of 250 to 35.
An undrawn yarn is obtained by spinning at 0° C. and a take-up speed of 100 to 6000 m/min. The preferred range of take-up speed is 2000 to 60
00m/min, more preferably 5500-6000m/min
Obtained by high productivity in minutes.

At the above-mentioned preferred take-off speed, the fibers are oriented and crystallized, and the heat treatment time during the post-stretching treatment can be shortened. The wind speed of the cooling air for cooling the yarn discharged from the nozzle is 0.2 to 3.0 m for 7 seconds, and asymmetric cooling is performed to give anisotropy in the cross-sectional direction to obtain three-dimensional crimp. The wind speed in this case is preferably 0.5 to 3.0 m/sec. The obtained undrawn yarn is usually subjected to two stages of stretching, and the first stage of stretching is performed at a temperature of 60 to 150°C at a maximum stretching ratio of 65 to 85%.
is preferable, and the second stage stretching is 80 to 95% of the maximum stretching ratio.
, the temperature is preferably 180 to 240°C. The drawn yarn obtained as described above is further improved in pill resistance by limited heat treatment at 200-250°C and 3-5% relaxation.
- to do. The polyester fibers obtained as described above may be used as they are as filament yarns, or may be crimped and then cut into appropriate lengths to form short fibers. Further, it is preferable to extend the three-dimensional crimp to form a twist before applying the mechanical crimp, and then apply the crimp, since the anti-pilling property can be further improved.

(Example) Parts in Examples indicate parts by weight unless otherwise specified.

1000 parts of dimethyl terephthalate (DMT), 5-sodium sulfoisophthalic acid dimethyl ester (r)
SN) is 2.3 mol% based on the total acid components, 7000 parts of ethylene glycol (EG), and R in formula (II) is a 2,2-dimethylpropylene group, and m+
45.3 parts of glycol with n=4 was placed in a transesterification reactor, and 0.38 parts of zinc acetate dihydrate, 0.5 parts of sulfurium acetate, and 0.3 parts of antimony trioxide were added to the transesterification reactor.
3 parts were added, and the transesterification reaction was carried out while raising the temperature to 1511 to 210° C. over 130 minutes while distilling off the by-product methanol. To this reaction system was further added 0.8 parts of dimethyl-2-carboe-1-xyethylphosphone, and the mixture was maintained for 10 minutes. The obtained product was transferred to a polycondensation reactor at 210°C, and the temperature was raised to 275°C over 80 minutes while the pressure of the reaction system was gradually reduced to 0.1 mmHg, and then held for 40 minutes to allow a polycondensation reaction. A polymerized polyester was obtained. The resulting copolymerized polyester had a melting point of 252°C and an intrinsic viscosity of 0.46.

The above copolymerized polyester was melted at 285°C and formed into a shape (slit width 0.20 mm, longitudinal direction 2.0 ITI11,
The undrawn yarn was extruded from a nozzle having spinning holes of 1 and 2 rrtn in the width direction at a rate of 2 g/min per hole and taken off at 2000 m/min. The first stage of stretching is carried out by 20%, and then the drawn yarn is stretched by 1.25% by contact with a heating roller at 220°C.
The fibers were heat treated at 40° C. and 5% relaxed, mechanically crimped, and then cut into 64+nm pieces to obtain short fibers.

The obtained short fibers were spun into yarn with a count of 1/30 meter using a conventional method, and then dyed under normal pressure with a basic dye to obtain a weft yarn of 28
After tufting with 2.5 cnl, one surface was cut and raised to obtain a raised fabric with a cut length of 5 nwn.

Comparative Example 1 - In the example described above, Y shape (slit width 0.111
Short fibers and raised cloth were produced in the same manner as in the example except that a nozzle having a spinning hole with a diameter of 111 mm and a side length of 0.3 mu was used.

Comparative Example 2.3 In Example 1, a nozzle with a circular (diameter 0.23 wn) spinning hole (Comparative Example 2) and a flat (length 0
．． Short fibers and raised cloth were produced in the same manner as in the example except that a nozzle (comparative example 3) having a spinning hole of 5 mm and width of 0.0 B+nm was used.

Comparative Example 4 Short fibers and raised cloth were produced in the same manner as in the above Example, except that polyethylene terephthalate (intrinsic viscosity: 0.62) was used instead of the copolymerized polyester.

The performance of the staple fibers and raised fabrics of the above Examples and Comparative Examples is shown in the table below. (Blank below) Table 120 = As seen in the table above, the fibers of the examples of this invention have good dyeing rates for disperse dyes and basic dyes, excellent light resistance, and the raised fabric is cut. sexual, anti-pill, erect;
It has excellent wear resistance and covering properties, and also has a good animal hair texture. Comparative Examples 1, 2, and 3, which have different cross-sectional shapes, are not much different from the Examples in fiber performance, but Comparative Example 1, which has a slight difference in cross-sectional shapes, has better cutability, uprightness, and resistance to fatigue than the Examples. Although the properties are only slightly inferior, the pile-pill properties and covering properties are poor, and the animal hair-like texture is significantly reduced. Comparative Example 2, which has a circular cross-sectional shape, has slightly inferior cuttability, but is inferior in pile pilling properties, uprightness, resistance to settling, and other performances. Comparative Example 3, which has a flat cross-sectional shape, is not so bad in pill resistance, but similarly to Comparative Example 2, its uprightness, fatigue resistance, and covering property are low. Comparative Example 4, in which a single polyester was used instead of a copolymerized polyester, had extremely low dyeability and poor cutability, pile pilling properties, and uprightness, but only slightly inferior sagging resistance and covering properties. .

The melting point of the copolymerized polyester in the above examples is a value measured under the conditions of differential scanning heating of 1ff (sample amount) Omg, nitrogen atmosphere, A temperature rate of 0°C/min. Also, the intrinsic viscosity is , 1 lll+ was determined at 30° C. using a mixed solution of phenol/te-1-lachloroethane (weight ratio 6:4).

Dispersible dye dyeing rate is Dispersor Fur Scarlet B (manufactured by ICT) 4.0% owf, Dispersor TL
(Dispersant, manufactured by Seisei Kagaku Kogyo Co., Ltd.) Ig/Q, bath ratio]:
100, the sample was dyed at normal pressure boiling temperature (98°C) for 90 minutes, and the basic dye dyeing rate was determined by Cevron Blue B (
DuPont) 5.0% owf, acetic acid and sodium acetate each 0.2 g/Q, bath ratio 1:]O00, the sample was stained for 90 minutes at normal pressure and boiling temperature, and the absorbance of the staining solution before and after dyeing was measured. It was calculated using the following formula.

Dyeing rate (%) = 100 (X-Y) /XX is the dyeing solution absorbance before dyeing, and ■ is the dyeing solution absorbance after dyeing.

Light resistance: Dispersible dye Resolin Red FB (manufactured by Bayer) 0.2% owf, Disper TL 1g/Q, bath ratio]
:100, the sample was dyed at normal pressure boiling temperature for 60 minutes, and after reduction cleaning by the usual method, JIS-L O8
The dyed material was irradiated with a fade-o-meter for 40 hours to photobleach the dyed material in accordance with No. 42, and was expressed as a fastness (grade) based on the blue scale standard, with grade 5 being the best.

The lower the cutting stress during cutting, the better the cuttability, so the stress during cutting was measured and the stress during cutting was 2 g/d.
2 is X, 2.0 to 1.4 g/d is △, 1.4-1.
2 g/d was evaluated as 0 if it was 0.1.2 g/d or less.

Anti-pill properties were graded from 1 to 5 based on the number of pills and the number of pills on the hair 10 hours after the TCI pilling test (JI
S-L1076). The uprightness was sensory evaluated as 5th grade when the nape was well raised, and 1st grade when the nape was flat. The resistance to settling is 20 g/
It shows the bulk retention property after being left for 1 hour under a load of crK, and the thickness before treatment is X. When the thickness after treatment is Xj,
Bulk retention rate (%)” [(Xo-Xj) /X0]
] If the calculated value in OO is 80% or more, ◎, 60% or more is 0
140% or more -1- is indicated by Δ, and less than 40% is indicated by X.

Covering properties were visually observed from the "-" side of the raised blanket and evaluated on a scale of 1 to 5 based on the degree to which the tuft holes were visible.

The wool texture was evaluated by sensory evaluation of the texture of a 100% wool raised fabric with the same structure, and the texture was the same as that of a 100% wool raised fabric.
A similar texture is indicated by O1, a slightly different texture is indicated by Δ, and a completely different texture is indicated by ×.

(Effects of the invention) As shown in the table above, the polyester fiber of this invention is
In addition to being easy to dye and having excellent light fastness, raised fabrics made from this fiber have excellent cutability, anti-pilling properties, uprightness, resistance to set, and covering properties, and have the same texture as wool napped fabrics. Also, because it is easily dyed, it can be blended with natural fibers and mixed colors. Furthermore, since the covering property is good, the basis weight of the raised cloth can be reduced. Furthermore, productivity is excellent and manufacturing costs are low. A raised blanket made of this fiber is suitable for baby products, vehicle seats, bedclothes, and various types of clothing.

124 = Procedural amendment 1985 117112 Patent application No. 217845 1988 Title of the invention Anti-pill easily dyeable polyester fiber 3 Relationship to the case of the person making the amendment Patent applicant's residence Dojimahama, Kita-ku, Osaka City 2-2-8 Name (3
16) Toyobo Co., Ltd. Rei 4 Agent Address: 2-6, Azuchi-cho, Higashi-ku, Osaka 1110-6
Subject of amendment: Detailed description of the invention in the Claims column of the specification.

7 Contents of the amendment (+) Corrections from page 1, line 5 of the specification tube to page 2, line 19 as shown in the appendix to the scope of claims.

(2) 4th line from the bottom of page 6 of the specification Corrected "total glycol component" to "total glycol component".

(3) Line 4 of page 6 of the specification Corrected "2 to 4 integers" to "2 to -(Φ-integer").

(4) Line 17, page 17 of the specification cylinder Corrected r7000 part j to ``partially cut''.

Attachment Claims [+] -- General formula (where R is a dicarboxylic acid residue, and at least 80
Mol% is terephthalic acid residue. R1 is a glycol residue, and at least 80 mol% of the total glycol component is ethylene glycol, tetramethylene glycol, 1
, 4-cyclohexane dimetatool. R2ke-G-C: 111.1 ('1~
．． R, -0+ position, l-, 1. ．． tO-river, R-edited carbon atom r divalent aliphatic hydrocarbon group with 4 to 20 carbon atoms, rll
, n same or different integers 3≦m 10n≦10.1
, j are the same or different − integers from 2 to −4−, and +
The glycol component represented by R2-09- occupies 1 to 10% by weight based on the produced polyester), and is composed of a copolymerized polyester having an intrinsic viscosity of 0.3 or more, Moment of inertia of the fiber cross section is the minimum moment of inertia (Tmjn)
and the maximum moment of inertia of area (IIIax) in the direction almost perpendicular to this (Tmjn / T + na
The ratio (Tci/
A pill-resistant and easily dyeable polyester fiber characterized in that lm1n) is 5/1 or less.

[2] General formulas (1) and (II) of copolymerized polyester
) in which R is 80 mol% or more is a terephthalic acid residue, and 0.5 to 5.0 mol% is a 5-metal sulfoisophthalic acid residue. Pillable and easily dyeable polyester fiber.

[3] The pill-resistant and easily dyeable polyester fiber according to claim 1, wherein R in the general formula (n) of the copolyester is a divalent aliphatic hydrocarbon group having a side chain.

Claims (1)

[Claims] [1] General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (However, R is a dicarboxylic acid residue, and at least 80
Mol% is terephthalic acid residue. R_1 is a glycol residue, at least 80 mol% of the total glycol component
is ethylene glycol, tetramethylene glycol, 1
, 4-cyclohexaline methanol. R_2 is -(C__iH_2_iO
)−＿＿mR_3−O−(C＿＿jH_2＿＿jO)−
___n, R_3 is a divalent aliphatic hydrocarbon group having 4 to 20 carbon atoms, m and n are the same or different integers, and 3≦
m+n≦10, i and j are the same or different 2 to 4 integers, and the glycol component represented by -(R_2-O)- occupies 1 to 10% by weight based on the polyester produced). It is made of a copolymerized polyester that is composed of units and has an intrinsic viscosity of 0.3 or more, and the moment of inertia of the cross section of the fiber has the minimum moment of inertia (Imin) and the maximum in the direction almost perpendicular to this. The ratio (Imin/I
max) is 1/2 to 1/20, and the ratio (Ici/
A pill-resistant and easily dyeable polyester fiber, characterized in that its Imin) is 5/1 or less. [2] General formulas (I) and (II) of copolymerized polyester
) in which 80 mol% or more of R is a terephthalic acid residue,
The pill-resistant and easily dyeable polyester fiber according to claim 1, wherein 0.5 to 5.0 mol% is 5-metal sulfoisophthalic acid residue. [3] The pill-resistant and easily dyeable polyester fiber according to claim 1, wherein R_3 in the general formula (II) of the copolyester is a divalent aliphatic hydrocarbon group having a side chain.