JP2012201987A - Short-cut polyester fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a short-cut polyester fiber which has superior dispersibility in water and is suitably used for obtaining a wet nonwoven fabric having adequate texture.SOLUTION: The short-cut polyester fiber contains polyester as a main component and 0.3-20.0 mass% of following components (A) and (B) in total; (A) an esterification reaction product which comprises a sulfonic acid group containing aromatic dicarboxylic acid and/or an ester-forming derivative thereof, polycarboxylic acid not containing a sulfonic group and/or an ester-forming derivative thereof, and polyalkylene glycol, and (B) polyalkylene glycol.

Description

  The present invention relates to a polyester shortcut fiber suitable for producing a mixed paper of polyester fiber and other fibers when producing a polyester nonwoven fabric by a wet method.

  Conventionally, a natural pulp, synthetic pulp, synthetic fiber shortcut cotton, or a mixture thereof is dispersed in an aqueous solution, and a wet nonwoven fabric is obtained by paper making. A method for obtaining a flexible wet nonwoven fabric excellent in mechanical properties is generally known.

  However, in order to produce a wet nonwoven fabric, natural short fibers, synthetic pulp, synthetic shortcut cotton, or a mixture of these are dispersed in an aqueous solution, and in the process of making paper, the shortcut short synthetic fibers are pseudo-adhered or entangled with each other. There is a problem that it is difficult to disperse uniformly in water.

  In order to solve this problem, a method for improving the dispersibility of short fibers by defining an oil agent component to be applied has been disclosed (for example, see Patent Documents 1 to 4). However, in these methods, in the wet nonwoven fabric manufacturing process, there is a problem that the oil agent drops off by strong stirring, reaggregation of short fibers over time, and the oil agent drops off at an appropriate temperature of pulp slurry of 40 to 60 ° C. It was still inferior in water dispersibility.

  As described above, a wet nonwoven fabric having excellent dispersibility in water and a good texture, and a polyester shortcut fiber suitable for obtaining a mixed paper of polyester fiber and other fibers have not been proposed yet.

JP 58-208499 A JP 58-208500 A Japanese Patent Publication No. 3-33837 JP-A-9-95891

  An object of the present invention is to solve the above-mentioned problems and to provide a polyester shortcut fiber suitable for obtaining a wet nonwoven fabric excellent in dispersibility in water and having a good texture.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the dispersibility in water of the obtained polyester shortcut fiber is remarkably improved by containing a specific component in the polyester fiber. The present invention has been reached.
That is, the gist of the present invention is as follows.
(1) The main component is polyester, and the following (A) and (B) components are added in a total of 0.3 to 20.0.
A polyester shortcut fiber characterized in that it is contained in an amount of%.
(A) Esterification reaction product comprising sulfonic acid group-containing aromatic dicarboxylic acid and / or ester forming derivative thereof, polycarboxylic acid not containing sulfonic acid group and / or ester forming derivative thereof, and polyalkylene glycol .
(B) Polyalkylene glycol.
(2) The polyester shortcut fiber according to (1), wherein the mass ratio of (A) and (B) is 5:95 to 95: 5.
(3) The polyester shortcut fiber according to (1) or (2), wherein the fiber length is 3 to 10 mm.

  The polyester shortcut fiber of the present invention is excellent in dispersibility in water and can maintain good dispersibility even when stirring or the like is repeated. Therefore, the polyester shortcut fiber can be suitably used for wet nonwoven fabrics and mixed paper.

  Hereinafter, the present invention will be described in detail.

  The polyester shortcut fiber of the present invention is a polyester fiber containing polyester as a main component and containing component (A) and component (B). The dispersion state of each of the component (A) and the component (B) in the polyester fiber is a non-uniform dispersion type (for example, a core-sheath type) dispersed only in a part of the polyester, even if it is a total dispersion type dispersed throughout the fiber. , Sea-island type).

  The polyester component (hereinafter may be referred to as “main component polyester”) as the main component of the polyester shortcut fiber in the present invention is not particularly limited, but for example, polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene Examples thereof include naphthalate, polylactic acid and the like as main components. Note that these polyester components may be copolymerized with isophthalic acid, sulfoisophthalate, ethylene oxide adducts of bisphenols, etc., as long as the purpose and effect are not impaired.

Next, the component (A) and the component (B) will be described.
Component (A) is a sulfonic acid group-containing aromatic dicarboxylic acid and / or an ester-forming derivative thereof (A-1), a polycarboxylic acid not containing a sulfonic acid group and / or an ester-forming derivative thereof (A-2) And an esterification reaction product comprising three components (A-1) to (A-3) of polyalkylene glycol (A-3) as constituent components.
Component (B) is polyalkylene glycol.

  Although it does not specifically limit as sulfonic acid group containing aromatic dicarboxylic acid (A-1) which comprises a component (A), For example, 5-sulfo isophthalic acid, 2-sulfo terephthalic acid, or these salts (For example, sodium salt) The ester-forming derivative (A-1) is not particularly limited, and lower alkyl esters of these sulfonic acid group-containing aromatic dicarboxylic acids (for example, sulfonic acid group-containing aromatic dicarboxylic acids). Ester of an acid and a lower alkyl diol having about 1 to 4 carbon atoms) or a salt thereof, an acid anhydride, and the like. Of these, from the viewpoint of polymerizability, sodium 5-sulfoisophthalate and sodium 5-sulfoisophthalate diethylene glycol ester (hereinafter SIPG) are preferred. Only one of the sulfonic acid group-containing aromatic dicarboxylic acid and its ester-forming derivative may be used, or both may be used in combination. Moreover, only one type of component may be used, or a plurality of types may be used in combination.

The polycarboxylic acid (A-2) that does not contain a sulfonic acid group constituting the component (A) is not particularly limited, and examples thereof include aliphatic dicarboxylic acids such as succinic acid, adipic acid, and sebacic acid, isophthalic acid, and terephthalic acid. An aromatic dicarboxylic acid such as an acid can be used, and the ester-forming derivative (A-2) is not particularly limited. However, the lower alkyl ester of a polycarboxylic acid not containing a sulfonic acid group (for example, a sulfonic acid group). And ester anhydrides of polycarboxylic acids not contained and lower alkyl diols having about 1 to 4 carbon atoms), acid anhydrides and the like. Of these, adipic acid, isophthalic acid, adipic acid diethylene glycol ester, and isophthalic acid diethylene glycol ester are preferred from the viewpoint of polymerizability. Polycarboxylic acids and their ester-forming derivatives not containing a sulfonic acid group, even using only either one may be used in combination of both. Moreover, only one type of component may be used, or a plurality of types may be used in combination.

  The polyalkylene glycol (A-3) constituting the component (A) is not particularly limited, and examples thereof include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and ethylene oxide / propylene oxide copolymer. From the viewpoint of improvement, polyethylene glycol (hereinafter abbreviated as “PEG”) is preferred. The number average molecular weight of the polyalkylene glycol is preferably 1000 to 30000, and more preferably 2000 to 22000. A plurality of types having different number average molecular weights may be used in combination. If the number average molecular weight is lower than 1000, thermal stability and bleed-out resistance may be slightly inferior, and if the number average molecular weight exceeds 30000, the esterification reaction may be slightly difficult to proceed.

  In the esterification reaction product (A), the polycarboxylic acid not containing a sulfonic acid group and / or its ester-forming derivative (A-2) component is an essential component for carrying out the esterification, When there is no component A-2), the esterification reaction product (A) cannot be polycondensed well.

  In the esterification reaction product (A) of the present invention, a sulfonic acid group-containing aromatic dicarboxylic acid and / or an ester-forming derivative thereof (A-1), a polycarboxylic acid not containing a sulfonic acid group and / or an ester-forming property thereof The reason why the resulting polyester shortcut fiber is easily dispersed uniformly in water by including the esterification reaction product (A) obtained by polycondensation of the derivative (A-2) and the polyalkylene glycol (A-3) is clear. However, for example, by polycondensation of component (A-1), component (A-2) and component (A-3), hydrophilicity and compatibility improvement derived from polyalkylene glycol and sulfonic acid group can be improved. From the viewpoint, the effect of improving the dispersibility of polyester shortcut fibers in water is achieved, and the bleeding out of the esterification product (A) is further suppressed It is estimated that the water dispersibility improving effect is exerted even after shedding of such oils.

  Even if the polyalkylene glycol itself is blended with the polyester and spun without using the esterification reaction product (A) obtained by copolymerization of the above three types, the hydration power of the polyalkylene glycol by the ether bond and the terminal hydroxyl group For this reason, although the dispersibility of the resulting polyester shortcut fibers in water is improved, bleed out occurs during melt spinning, resulting in inferior spinnability, and dispersion in water due to bleed out during storage or dropping off of oils. The effect of improving the performance is reduced.

  The esterification reaction product (A) can be obtained by subjecting the above-mentioned three components [(A-1) to (A-3)] to an esterification reaction in the same manner as in a normal polyester production method. As the polymerization catalyst used in the polymerization reaction, known catalysts such as antimony trioxide, tetrabutyl titanate, dibutyltin oxide, and germanium dioxide can be used. Of these, tetrabutyl titanate is preferable from the viewpoint of high catalytic activity at low temperatures.

  As each content in a component (A), from a viewpoint of the balance of a water dispersibility improvement effect and compatibility with polyester, a component (A-1) is 5-35 mol%, and a component (A-2) is It is preferable that 5-45 mol% and a component (A-3) are 50-90 mass%, Among these, a component (A-1) is 15-35 mol%, and a component (A-2) is 5-25 mol. %, (A-3) is more preferably 60 to 90% by mass.

  The number average molecular weight of the component (A) is preferably 1000 to 30000, and more preferably 4000 to 20000. If the number average molecular weight is less than 1000, the thermal stability and bleed-out resistance are deteriorated, which is not preferable. If it exceeds 30000, the melt viscosity becomes high, and it tends to be difficult to uniformly disperse it in the main component.

  The component (B) is not particularly limited as long as it is a polyalkylene glycol, and examples thereof include PEG, polypropylene glycol, polytetramethylene glycol, ethylene oxide / propylene oxide copolymer, and among them, PEG is preferable from the viewpoint of handleability. The number average molecular weight is preferably 1000 to 30000, more preferably 4000 to 20000. When the number average molecular weight is less than 1000, the thermal stability tends to be poor, and when the number average molecular weight exceeds 30000, the melt viscosity becomes high and the component (A) and the component (B) can be mixed uniformly. It tends to be difficult.

  The mass ratio of the component (A) to the component (B) is preferably 5:95 to 95: 5, and more preferably 10:90 to 90:10. If the mass ratio of the component (A) is less than 5, the compatibility with the main component polyester tends to be inferior. On the other hand, if the mass ratio of the component (A) exceeds 95, depending on the combination of the components (A) Is not preferable because the total amount of hydroxyl groups and ether groups of the component (A) and the component (B) is insufficient, and the water dispersibility may deteriorate due to repeated stirring.

  Furthermore, the total content of the component (A) and the component (B) in the polyester shortcut fiber of the present invention requires 0.3 to 20.0% by mass, preferably 2 to 20.0% by mass, 5-20.0 mass% is more preferable, and 12-20.0 mass% is still more preferable. When the total content of the component (A) and the component (B) is less than 0.3% by mass, the total amount of hydroxyl groups in the fiber is insufficient, so that dispersibility in water deteriorates due to repeated stirring. On the other hand, if it exceeds 20.0% by mass, the spinning operability is deteriorated, which is not preferable.

  In the polyester shortcut fiber of the present invention, it is a core-sheath type composite fiber, and mainly contains the components (A) and (B) of the present invention in a high concentration so that the dispersibility in water is improved while improving the spinnability. Since it can improve, it is especially preferable.

  The total content of the component (A) and the component (B) in the sheath of the core-sheath composite fiber is preferably 0.3 to 50.0% by mass, and more preferably 2 to 35.0% by mass. This is particularly preferable because it is superior in dispersibility in water as compared with the uniform dispersion type.

  As the state in which the component (A) and the component (B) are contained in the polyester shortcut fiber of the present invention, the effect can be obtained in any state as long as the component (A) and the component (B) are contained. That is, for example, components (A) and (B) are copolymerized and contained in the main component polyester, and components (A) and (B) are mixed (blended) and contained in the main component polyester. There are states, and the effects of the present invention can be achieved in any state.

  The order of adding the component (A) and the component (B) is not particularly limited, but the method of sequentially adding the component (A) and the component (B) to the polyester main component, the component (A) and the component (B) are added. The method of adding simultaneously, the method of adding after mixing a component (A) and a component (B) previously, and making it a mixture (C) is mentioned, Especially, from a uniform dispersible viewpoint, a component (A) and a component (B It is preferable that the mixture (C) in which is mixed) is added to the polyester main component and mixed, or at least a part thereof is copolymerized. By adding the mixture (C) in which the component (A) and the component (B) are mixed in advance to the polyester main component, the component (A) and the component (B) are more uniformly dispersed in the polyester component as the main component. As a result, it is possible to effectively improve the dispersibility of the obtained polyester shortcut fiber in water and its durability.

  Although it does not specifically limit as a method to obtain the mixture (C) which mixed the component (A) and (B), It mixes at 80-120 degreeC for 1 to 4 hours using mixing apparatuses, such as a mixer. Can be manufactured.

  The fiber form of the present invention may be produced by any method such as filaments, staples, spun yarn obtained by spinning staples with a fine spinning machine.

  The polyester shortcut fiber of the present invention includes various pigments, dyes, colorants, water repellents, water absorbents, flame retardants, stabilizers, antioxidants, ultraviolet absorbers, metal particles, inorganic compound particles, crystal nucleating agents, lubricants. Plasticizers, antibacterial agents, fragrances and other additives can be mixed depending on the intended use.

  Next, an example of the method for producing the polyester shortcut fiber of the present invention (when mixing the component (A) and the component (B) to create a mixture (C) and mixing the mixture (C) into the main component) is used. I will explain.

First, a component (A) and a component (B) are mixed for 1-4 hours using a mixer at 80-120 degreeC, and a mixture (C) is manufactured. Next, for example, the main component and the mixture (C) are mixed by any one of the following methods 1 to 5.
1. A method in which the main component polyester and the mixture (C) are previously dry blended and supplied to a single melt spinning machine.
2. A method in which the main component polyester and the mixture (C) are blended with a melt kneader to produce chips of a desired concentration, and then the chips are supplied to a normal melt spinning machine.
3. A method in which a master chip is prepared so that the mixture (C) has a high concentration of the main component polyester and the mixture (C), and then the master chip and the polyester component are dry blended and supplied to a single melt spinning machine.
4). A method in which the master chip (mixture (C) contains a high concentration) and the main component are supplied to separate melt spinning machines and blended in a polymer line or nozzle pack after melting.
5. A method in which the main component and the mixture (C) are supplied to separate melt spinning machines and blended in a polymer line or nozzle pack after melting.

  Next, the polymer mixed and melted by the above-mentioned method is weighed with a metering pump, discharged from a single component spinneret, and the spun yarn is threaded using a known cooling device such as a horizontal spraying device or an annular spraying device. The polyester shortcut fiber of the present invention can be obtained by cooling the strip, applying the oil agent, then scooping out and cutting the resulting long fiber. As a spinning method, a high-speed spinning of 2000 m / min or more is wound as a semi-undrawn yarn (POY method) or a one-step method of drawing and heat-treating in a winding process, once a high-speed spinning of 2000 m / min or more, or 2000 m / min It may be produced by any method such as a two-step method in which a yarn wound by low-speed spinning of less than min is drawn and heat treated. When the cross-sectional shape is a core-sheath type, the polymer mixed by the above-described method is discharged from the core-sheath composite spinneret with the sheath part and polyester as the core part, similarly cooled, and an oil agent is applied.

  Next, the present invention will be specifically described with reference to examples. In addition, evaluation of each characteristic in an Example is as follows.

(1) Melting point The temperature which gives the extreme value of the melting absorption curve measured with a differential scanning calorimeter (DSC7 manufactured by Perkin Elmer Co., Ltd.) at a temperature rising rate of 20 ° C./min was defined as the melting point.

(2) Intrinsic viscosity [η]
An equimass mixed solution of phenol / ethane tetrachloride was used as a solvent, and measurement was performed at a temperature of 20 ° C. using an Ubbelohde viscometer.

(3) Number average molecular weight Measured by gel permeation chromatography (GPC) method using tetrahydrofuran as a solvent. Three types of fillers, Styragel HR 54460 and 44225 and Ultrastyragel 10571, were used as fillers, and the number average molecular weight in terms of polystyrene was measured using a refractometer.

(4) Fineness It was measured by the method of JIS L-1015-7-5-1A.

(5) Fiber length It measured by the method of JIS L-1015-7-4-1C.

(6) Spinning operability The total number of yarn breakage when spinning continuously with 8 spindles for 24 hours was converted into the number of yarn breakage per ton of undrawn yarn collected, and evaluated according to the following evaluation criteria.
Evaluation Number of yarn breaks ○: 1.0 times or less ×: Over 1.0

(7) Dispersibility in water 1 kg of 30 ° C water is weighed in a 2000 cm ³ beaker, and 1.0 g of polyester shortcut fiber is added to the beaker, and a DC stirrer (a stirring blade is a three-screw type with a diameter of about 50 mm). Stirring was performed under the conditions of a rotational speed of 3000 rpm and a stirring time of 1 minute, and the dispersion state after 1 stir, 5 th and 10 th stir was judged visually by the following evaluation criteria. In addition, if it was (circle)-(triangle | delta), it was set as the pass.
Evaluation Number of tying fibers ○: 0 △: 1 to 5 ×: 6 or more

(8) Dispersibility in high-temperature water Dispersibility was evaluated in the same manner as (7) except that 50 ° C. hot water was used instead of 30 ° C. water.

(9) Dispersion stability with time In the same manner as in (7), the mixture was stirred at 3000 rpm for 1 minute and then allowed to stand at 30 ° C. for 3 days, and then stirred again at 3000 rpm for 1 minute to evaluate dispersibility.

Example 1
[Production of mixture (C)]
In a polycondensation reaction vessel, as component (A-1), as a component (A-1), a 40% ethylene glycol solution of sodium 5-sulfoisophthalate polyethylene glycol diester (SIPG) (average molecular weight of polyethylene glycol moiety: 356) (PIPE-40L Sanyo Chemical Industries) 108 parts (26 mol%), 29 parts adipic acid and 10 parts isophthalic acid (74 mol%) as component (A-2), and PEG (PEG-) having a number average molecular weight of 8300 as component (A-3) 6000S (manufactured by Sanyo Chemical Industries) 830 parts (29 mol%), 9 parts "Irganox 245" (Ciba Specialty Chemicals, hindered phenol antioxidant) as an antioxidant, tetrabutyl as a polymerization catalyst 0.2 parts of titanate was added, and the temperature was raised to 190 ° C. under a reduced pressure of 5 mmHg. Under these conditions, an ester exchange reaction was performed for 12 hours while removing excess ethylene glycol and water to obtain an esterification reaction product (component (A)).
Next, 226 parts of PEG having a number average molecular weight of 20000 (PEG-20000, manufactured by Sanyo Kasei Kogyo Co., Ltd.) was added as a component (B), and melt-mixed at 100 ° C. for 2 hours to obtain a mixture (C).
[Manufacture of polyester shortcut fibers]
Polyethylene terephthalate (PET) having a melting point of 255 ° C. and an intrinsic viscosity of 0.68 is used as the main component polyester, and the mixture (C) obtained by the above method is dried by a conventional method, and then the mixture (C) in the fiber. The mixture was dry blended so that the ratio was 3.0% by mass, supplied to a melt extruder, and melt kneaded at 285 ° C. Subsequently, the polymer was discharged from a die heated to 285 ° C., and melt-spun at a spinning speed of 700 m / min to obtain an undrawn fiber. Next, the obtained undrawn yarn was drawn at a drawing temperature of 65 ° C. and a draw ratio of 3.70 times to obtain a drawn yarn, cut into a fiber length of 5 mm, and a polyester shortcut fiber having a fineness of 2.2 dtex was obtained.

Examples 2-3 and Comparative Examples 1-3
A polyester shortcut fiber was obtained in the same manner as in Example 1 except that the ratio of the mixture (C) was changed as shown in Table 1.

Example 4
Polybutylene terephthalate (melting point: 225 ° C.) was used as the main component polyester, and after the mixture (C) obtained in Example 1 was dried by a conventional method, the ratio of the mixture (C) in the fiber was 3. It was dry blended with polybutylene terephthalate so as to be 0% by mass, supplied to a melt extruder, and melt kneaded at 285 ° C. Subsequently, the polymer was discharged from a die heated to 285 ° C. and melt-spun at a spinning speed of 700 m / min to obtain an undrawn yarn. Next, the obtained undrawn yarn was drawn at a drawing temperature of 65 ° C. and a draw ratio of 3.20 times to obtain a drawn yarn, cut into a fiber length of 5 mm, and a polyester shortcut fiber having a fineness of 2.2 dtex was obtained.

Examples 5-6, Comparative Examples 4-6
Except having changed the ratio of the mixture (C) as shown in Table 1, it carried out like Example 4 and obtained the polyester shortcut fiber.

Example 7
Polylactic acid (melting point: 170 ° C.) was used as the main component polyester, and after the mixture (C) obtained in Example 1 was dried by a conventional method, the ratio of the mixture (C) in the fiber was 3.0. It was dry blended with polylactic acid so as to have a mass%, supplied to a melt extruder, and melt kneaded at 230 ° C. Subsequently, the polymer was discharged from a die heated to 230 ° C. and melt-spun at a spinning speed of 700 m / min to obtain an undrawn yarn. Next, the obtained undrawn yarn was drawn at a drawing temperature of 65 ° C. and a draw ratio of 3.20 times to obtain a drawn yarn, cut into a fiber length of 5 mm, and a polyester shortcut fiber having a fineness of 2.2 dtex was obtained.

Examples 8-9, Comparative Examples 7-9
Except having changed the ratio of mixture (C) as shown in Table 1, it carried out like Example 7 and obtained the polyester shortcut fiber.

Example 10
Polyethylene terephthalate (melting point: 255 ° C.) was used as the core, and the mixture (C) obtained in Example 1 and polyethylene terephthalate (melting point: 255 ° C.) were used as the sheath. After the mixture (C) obtained in Example 1 was dried by a conventional method, it was dry blended with the sheath polymer so that the ratio of the mixture (C) in the fiber was 3.0% by mass (in the sheath portion). The ratio of the mixture (C) is 6.0% by mass), supplied to a melt extruder, and weighed so that the core: sheath = 50: 50 using a concentric core-sheath composite spinneret with 1014 holes and a circular cross section, Melt spinning was performed at a spinning temperature of 290 ° C. and a spinning speed of 700 m / min to obtain an undrawn yarn of a composite fiber. Next, the obtained undrawn yarn was drawn at a drawing temperature of 65 ° C. and a draw ratio of 3.20 times to obtain a drawn yarn, cut into a fiber length of 5 mm, and a core-sheath type polyester shortcut fiber having a fineness of 2.2 dtex. Obtained.

Examples 12 to 13 and Comparative Examples 10 and 12
Except having changed the ratio of the mixture (C) as shown in Table 1, it carried out like Example 10 and obtained the core-sheath-type polyester shortcut fiber.

Example 11
Except having changed the core-sheath ratio of a fiber cross section as shown in Table 1, it carried out like Example 10 and obtained the core-sheath-type polyester shortcut fiber.

Comparative Example 11
Except having changed the core-sheath ratio of a fiber cross section as shown in Table 1, it carried out similarly to the comparative example 10, and obtained the core-sheath-type polyester shortcut fiber.

Example 14
Polyethylene terephthalate (melting point: 255 ° C.) was used as the core, and polyethylene terephthalate (softening point: 130 ° C.) obtained by copolymerizing 40 mol% of the mixture (C) obtained in Example 1 and isophthalic acid was used as the sheath. . After the mixture (C) obtained in Example 1 was dried by a conventional method, it was dry blended with the sheath polymer so that the ratio of the mixture (C) in the fiber was 3.0% by mass (in the sheath portion). The ratio of the mixture (C) is 6.0% by mass), supplied to a melt extruder, and weighed so that the core: sheath = 50: 50 using a concentric core-sheath composite spinneret with 1014 holes and a circular cross section, Melt spinning was performed at a spinning temperature of 290 ° C. and a spinning speed of 700 m / min to obtain an undrawn yarn of a composite fiber. Next, the obtained undrawn yarn was drawn at a drawing temperature of 65 ° C. and a draw ratio of 3.20 times to obtain a drawn yarn, cut into a fiber length of 5 mm, and a core-sheath type polyester shortcut fiber having a fineness of 2.2 dtex. Obtained.

Examples 16-17, Comparative Examples 13-14, 16
Except having changed the ratio of the mixture (C) as shown in Table 1, it carried out like Example 14 and obtained the core-sheath-type polyester shortcut fiber.

Example 15
Except having changed the core-sheath ratio of a fiber cross section as shown in Table 1, it carried out like Example 14 and obtained the core-sheath-type polyester shortcut fiber.

Comparative Example 15
Except having changed the core-sheath ratio of a fiber cross section as shown in Table 1, it carried out similarly to the comparative example 14, and obtained the polyester shortcut fiber.

Examples 18-21, Comparative Examples 17-20
Except having changed the molar ratio of a component (A-1), a component (A-2), and a component (A-3) as shown in Table 1 and creating mixture (C), it carried out similarly to Example 3, and producing it. And polyester shortcut fibers were obtained.

  Table 1 shows the evaluation results of the fibers obtained in Examples 1 to 21 and Comparative Examples 1 to 20.

  As is clear from Table 1, the fibers of Examples 1 to 21 were excellent in dispersibility in water, dispersibility in high temperature water, and dispersion stability over time.

On the other hand, since the fibers of Comparative Examples 1, 4, 7, and 13 did not contain the mixture (C), they were inferior in water dispersibility. Since the fibers of Comparative Examples 2, 5, 8, 10, 11, 14, and 15 had a small content of the mixture (C), the dispersibility in water was poor. Since the fibers of Comparative Examples 3, 6, 9, 12, and 16 had a high content of the mixture (C), the spinning operability was remarkably deteriorated, and polyester shortcut fibers could not be obtained.

Claims (3)

A polyester shortcut fiber comprising polyester as a main component and containing a total of 0.3 to 20.0 mass% of the following components (A) and (B).
(A) An esterification reaction product comprising a sulfonic acid group-containing aromatic dicarboxylic acid and / or an ester-forming derivative thereof, a polycarboxylic acid not containing a sulfonic acid group and / or an ester-forming derivative thereof, and a polyalkylene glycol.
(B) Polyalkylene glycol. The polyester shortcut fiber according to claim 1, wherein the mass ratio of (A) to (B) is 5:95 to 95: 5. The polyester shortcut fiber according to claim 1 or 2, wherein the fiber length is 3 to 10 mm.