JP3172582B2 - Nonwoven fabric with excellent water absorption performance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonwoven fabric suitable for use in medical applications such as facing materials, wiping cloth interlinings, clothing, disposable surgical gowns, etc., which require water absorption performance.

[0002]

2. Description of the Related Art Conventionally, an entangled non-woven fabric comprising a fine fiber layer in which the surface layer is densely entangled, and a lower portion formed of an entangled layer of ultra-fine fiber bundle-like fibers, bundles the ultra-fine fibers immediately after spinning and partially adheres. A single fiber, a chrysanthemum-shaped fiber with one component radially interposed between other components, a multi-layer bimetallic fiber, a sea-island fiber composed of two or more components, and a large number of ultrafine fibers continuous in the fiber axis direction Sequence set and combined with other components and / or
Alternatively, a fiber web is formed using a so-called ultrafine fiber-forming fiber (hereinafter, sometimes referred to as easily splittable fiber) such as a polymer mutual array fiber partially bonded to form one fiber, and this is used as a needle punch. After that, a high-speed fluid flow is brought into contact and fibrillated to form a fine entanglement to form a nonwoven fabric structure. The non-woven fabric obtained by such a method is used, for example, as a leather-like sheet having a dense entangled non-woven fabric as a surface layer.

[0003] In recent years, polyester fibers represented by polyethylene terephthalate have been frequently used in the field of fibers, especially in the field of nonwoven fabrics. For example, sanitary materials such as baby diapers, diaper liners, sanitary products, counter cloths for the restaurant industry, non-sanitary materials such as drainage bags for kitchen utensils, base cloths and fixed sheets for ship drugs, BACKGROUND ART Nonwoven fabrics made of polyester fibers have been widely used in medical fields such as hospital surgical gowns and masks. Among these nonwoven fabric products, in particular, baby diapers, sanitary products and the like are required to have more durable water absorption performance than conventional ones.

[0004]

SUMMARY OF THE INVENTION A high-speed fluid flow is brought into contact with a fiber web made of conventional microfiber-forming fibers to branch easily splittable fibers into microfibers or bundles of microfibers, and at the same time densely entangle them. Non-woven fabric structure, or a non-woven structure having a surface layer having such a structure, in the field of using the non-woven fabric alone, ultra-fine fibers are fluffed and cling to hands and skin, and are too soft and stiff. However, there is a disadvantage that the product form cannot be maintained. Furthermore, since the cross-sectional shape of the ultrafine fibers is relatively homogeneous, the strength of the entanglement is not sufficient, and the strength of the nonwoven fabric is not sufficient.

[0005] The water absorption performance has been conventionally provided by a so-called post-processing method in which the surface of the nonwoven fabric is treated with an oil agent or the like. However, there is a drawback that water is dropped and water absorption performance is extremely reduced, so that there is a limit in use. In particular, the wet-type nonwoven fabric used for the surface material of diapers and sanitary pads always undergoes a paper-making process in water during the manufacturing process.
In the printing method, the hydrophilizing agent falls off during papermaking,
Many end products do not have sufficient performance.

SUMMARY OF THE INVENTION An object of the present invention is to provide a nonwoven fabric which has fibers densely entangled on at least one side, is bulky and stiff, has a high strength of the nonwoven fabric, and has excellent durability and excellent water absorption performance. .

[0007]

According to the present invention, an object of the present invention is to provide an easily splittable fiber consisting of two or more polymers which are physically or chemically different from each other as a main constituent fiber, and to obtain the following formula (1). A nonwoven fabric which satisfies the following requirements. One component of the polymer constituting the fiber is mainly a dicarboxylic acid unit, a diol unit, and a compound represented by the general formula (I):

Embedded image [In the formula, x and y each represent 0 or 1, and Z represents a formula -O- (R ₂ -O) n ₁ -R ₁ (wherein, R ₁ has 1 to ₁ carbon atoms)
Represents a hydrocarbon group of 18, R ₂ represents an alkylene group,
n ₁ represents a monovalent group represented by the number of 10 to 100 representing the average degree of polymerization)

The structural unit represented by the general formula (II)

-O- (R ₃ -O) n _2-

(Wherein, R ₃ represents an alkylene group, and n ₂ is a number of 10 to 100 representing an average degree of polymerization)

And a structural unit represented by the general formula (II)
I)

[0012]

Embedded image

(Wherein, Ar represents a trivalent aromatic group;
Represents a metal atom)

The content of the structural units represented by the general formulas (I) and (II) is 1 to 49% by weight, respectively, and the general formulas (I) and (II) ) Is 2 to 50% by weight, and the content of the structural unit represented by the general formula (III) is 0 to 0 with respect to all the acid components constituting the copolymerized polyester. It is attained by providing a nonwoven fabric having excellent water absorbability, which is a copolymerized polyester having an intrinsic viscosity of 10 mol% and an intrinsic viscosity of 0.5 dl / g or more.

L × ρ ≧ 7 (1)

[Wherein L is the wicking length after washing 10 times (m
m) and ρ is the apparent density of the nonwoven fabric (g / cm ³ )]

One of the structural units of the above copolymerized polyester is
The dicarboxylic acid unit is a structural unit in which two hydroxyl groups in two carboxyl groups are removed from a dicarboxylic acid molecule, and has the general formula

[0018]

Embedded image

(Wherein, R ₄ represents a divalent organic group)

## EQU1 ## Examples of the divalent organic group represented by R ₄ include divalent aromatic hydrocarbon groups such as p-phenylene group, m-phenylene group, naphthalenediyl group, (biphenyl) diyl group, etc .; A divalent aliphatic hydrocarbon group such as a methylene group; and a divalent alicyclic hydrocarbon group such as a 1,4-cyclohexyl group.

The copolymerized polyester may contain only one type of dicarboxylic acid unit or two or more types of dicarboxylic acid units. However, a copolymerized polyester having excellent mechanical properties required for fiber use is not preferred. From the viewpoint of obtaining, it is preferable that 70 mol% or more of the dicarboxylic acid unit is a terephthaloyl group.

One of the constituent units of the above-mentioned copolymerized polyester is
The diol unit is a structural unit in which two hydrogen atoms in two hydroxyl groups are removed from a diol molecule.
General formula

-0-R ₅ -O-

(Wherein, R ₅ represents a divalent organic group)

## EQU2 ## The divalent organic group represented by R _5, for example, ethylene group, trimethylene group, pentamethylene group, hexamethylene group, 2,2-dimethyl trimethylene group, 3-methyl pentamethylene group, nonamethylene group, 2-methyl Divalent aliphatic hydrocarbon group such as octamethylene group; divalent alicyclic hydrocarbon group such as dimethylcyclohexane-α, α'-diyl group; 2,2-diphenylpropane-4 ', 4 "- And divalent aromatic groups such as diyl group and diphenylsulfone-4,4'-diyl group.

The diol unit contained in the polymerized polyester may be only one type or two or more types. Copolymerized polyesters having excellent mechanical properties required for fiber applications are used. From the obtained point, 70 mol% or more of the diol unit has 2 carbon atoms such as ethylenedioxy group, trimethylenedioxy group, tetramethylenedioxy group, pentamethylenedioxy group, hexamethylenedioxy group and the like. It is preferably a divalent structural unit in which two hydrogen atoms in two hydroxyl groups have been removed from the straight-chain alkylene glycol molecules of (1) to (6).

One of the structural units of the above copolymerized polyester
Is a structural unit represented by general formula (I):

[0028]

Embedded image

Wherein Z is as defined above.

The structural unit represented by the general formula (I-2)

[0031]

Embedded image

(Wherein Z is as defined above)

The structural unit represented by the general formula (I-3)

[0034]

Embedded image

Wherein Z is as defined above.

And the like. The structural unit represented by the general formula (I) is usually an ester bond (—CO—O—) or an ether bond between the structural units or another structural unit such as the dicarboxylic acid unit and the diol unit. (-O-) is formed and incorporated into the main chain of the copolymerized polyester of the present invention to form a side chain type polyoxyalkylene structure. Examples of the hydrocarbon group represented by R ₁ in the formula representing the group Z include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and ter.
carbon number 1 such as t-butyl, n-pentyl, n-octyl, 2-ethylhexyl, n-dodecyl, n-stearyl
-18 alkyl groups; 3-1 carbon atoms such as cyclohexyl
Preferred are cycloalkyl groups having 8; aryl groups having 6 to 18 carbon atoms such as phenyl and nonylphenyl. When the number of carbon atoms of the hydrocarbon group R ₁ is 19 or more, excellent in surface wettability ease, no fiber excellent in water absorption and water retention obtained. Further, as the alkylene group represented by R ₂ in the formula representing the group Z, an alkylene group having 2 to 4 carbon atoms such as an ethylene group or a propylene group is preferable, and a fiber excellent in surface wettability, water absorption and water retention is obtained. Therefore, an ethylene group is more preferable. As R ₂ , a plurality of types of alkylene groups may be present simultaneously, such as a combination of an ethylene group and a propylene group. N ₁ in the formula representing the group Z is a number representing the average degree of polymerization of the polyoxyalkylene moiety, and is a number in the range of 10 to 100. When n ₁ is less than 10, a fiber excellent in surface wettability, water absorption and water retention cannot be obtained. On the other hand, when n ₁ is a number exceeding 100, the effects such as surface wettability, water absorption and water retention reach saturation, and the fiber is more likely to be colored. Surface wettability,
In terms of water absorption, water retention and coloring, n ₁ is 20 to
It is preferably a number in the range of 90.

One of the structural units of the above copolymerized polyester
The structural unit represented by the general formula (II) generally forms an ester bond with the dicarboxylic acid unit or the structural unit represented by the general formula (III) and is incorporated into the main chain of the copolymerized polyester. Thus, a main chain type polyalkylene structure is formed. As the alkylene group represented by R ₃ in the general formula (II), an alkylene group having 2 to 4 carbon atoms such as an ethylene group or a propylene group is preferable, and a fiber having excellent surface wettability, water absorption and water retention can be obtained. For this reason, an ethylene group is more preferred. As R ₃ , a plurality of types of alkylene groups may be present simultaneously, such as a combination of an ethylene group and a propylene group. N ₂ in the general formula (II) is a number representing the average degree of polymerization of the polyoxyalkylene moiety;
It is a number in the range of 10-100. n ₂ is the surface wetting ease if a number less than 10, good fibers not obtained water absorption and water retention. On the other hand, when n ₂ is a number exceeding 100, the effects such as surface wettability, water absorption and water retention reach saturation, and the fiber is more likely to be colored. N ₂ is preferably a number in the range of 20 to 90 in terms of surface wettability, water absorption, water retention, coloring and the like.

The structural unit represented by the general formula (I) and the structural unit represented by the general formula (II) contained in the copolymerized polyester may be only one type or two types.
The content of the structural unit represented by the general formula (I) and the structural unit represented by the general formula (II) may be in the range of 1 to 49% by weight, respectively, and The structural unit represented by the general formula (I) and the general formula (I
It is necessary that the total content of the structural units represented by I) is in the range of 2 to 50% by weight, preferably in the range of 3 to 40% by weight, and more preferably 5 to 3% by weight based on the copolymerized polyester.
Particularly preferred is a range of 0% by weight. When the total content of the structural unit represented by the general formula (I) and the structural unit represented by the general formula (II) is less than 2% by weight, the surface wettability of the resulting fiber may be insufficient. Yes, 50% by weight
If the ratio exceeds the above, mechanical properties such as the strength of the obtained fiber may be reduced.

One of the structural units of the above copolymerized polyester
The structural unit represented by the general formula (III) is usually the above-mentioned diol unit, the structural unit represented by the general formula (I),
Alternatively, it is incorporated in the main chain of the copolymerized polyester by forming an ester bond with the structural unit represented by the general formula (II). Ar in the general formula (III) represents a trivalent aromatic group, and includes a 1,3,5-benzenetriyl group,
Benzenetriyl groups such as 2,3-benzenetriyl group and 1,2,4-benzenetriyl group; 1,3,6-naphthalenetriyl group, 1,3,7-naphthalenetriyl group;
And naphthalenetriyl groups such as 1,4,5-naphthalenetriyl group and 1,4,6-naphthalenetriyl group. M represents a metal atom, and is preferably an alkali metal such as lithium, sodium, and potassium.

The general formula (I) contained in the copolymerized polyester
The structural unit represented by II) may be only one type or two or more types, and the content of the structural unit represented by the general formula (III) is contained in the copolymerized polyester. The amount is in the range of 0 to 10 mol%, preferably 0.5 to 7 mol%, of all the acid components. When the content of the structural unit represented by the general formula (III) exceeds 10 mol%, the content increases during the polycondensation reaction due to the ionic interaction of the metal sulfonate component in the structural unit represented by the general formula (III). Viscosity may occur, making it difficult to carry out the polycondensation reaction until the resulting polyester has the desired intrinsic viscosity.

The content of the structural unit represented by the general formula (I) and the structural unit represented by the general formula (II) and the content of the general formula (I
The relative proportion of the content of the structural unit represented by II) is defined as the percentage by weight of the structural unit represented by the general formula (I) and the structural unit represented by the general formula (II) based on the copolymer polyester to be formed. When the total is represented by Y ₀ (% by weight) and the molar percentage of the structural unit represented by the general formula (III) based on all the contained acid components is represented by Z ₀ (mol%), the value of Y ₀ / Z ₀ is obtained. Is preferably in the range of 2 to 40, since a fiber having both particularly improved surface wettability and mechanical performance is obtained.

The above-mentioned copolymerized polyester is mainly
It comprises a dicarboxylic acid unit, a diol unit, a structural unit represented by the general formula (I), a structural unit represented by the general formula (II), and a structural unit represented by the general formula (III). The structural unit may be contained in such an amount that the function and effect of the present invention are not lost. Examples of the structural units that may optionally have are hydroxycarboxylic acid units such as p-oxybenzoic acid units and p- (β-oxyethoxy) benzoic acid units; glycerin units, and trimethylo-
Triol units such as lepropane units; tetraol units such as pentaerythritol units; trimellitic acid units;
And tricarboxylic acid units such as trimesic acid units; and tetracarboxylic acid units such as pyromellitic acid units.

The above copolymerized polyester is preferably dissolved in a mixed solvent of phenol and tetrachloroethane (weight ratio: 1: 1), and has an intrinsic viscosity measured at 30 ° C. of 0.5 dl / g or more. When the intrinsic viscosity of the copolymerized polyester is less than 0.5 dl / g, breakage during melt spinning is remarkable. On the other hand, when the intrinsic viscosity is too large, the melt viscosity becomes too large and spinnability may be poor. Therefore, from the viewpoint of reducing troubles in the fiberization process, the intrinsic viscosity of the copolymerized polyester is in the range of 0.55 to 1.5 dl / g,
In particular, it is preferably in the range of 0.6 to 1.0 dl / g.

The above-mentioned copolymerized polyester can be produced according to a known method. For example, when a polyester is produced by subjecting a dicarboxylic acid or an ester-forming derivative thereof to a polycondensation reaction with a diol or an ester-forming derivative thereof, a comonomer containing a side chain type polyoxyalkylene group may be further used as another monomer. , Main chain type polyoxyalkylene group-containing comonomer and metal sulfone
The desired amount of each of the terpolymer-containing comonomer is added to the reaction system at any stage until the polycondensation reaction is completed, and the polycondensation reaction is performed until the intrinsic viscosity reaches a desired value of 0.5 dl / g or more. Manufactured by

As the dicarboxylic acid, terephthalic acid,
Aromatic dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid and diphenyldicarboxylic acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid; aliphatic dicarboxylic acids such as sebacic acid and adipic acid. Examples of the ester-forming derivative of dicarboxylic acid include lower alkyl esters such as dimethyl ester and diethyl ester of dicarboxylic acid described above. The diols are ethylene glycol, 1,3
-Propanediol, 1,4-butanediol, 1,5
-Pentaneddiol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentaneddiol, 1,9-nonanediol, 2-methyl-1,8
Aliphatic diols such as octanediol; alicyclic diols such as 1,4-cyclohexanedimethanol; 2,2-
Bis (4-hydroxyphenyl) propane, 4,4'-
And aromatic diols such as sulfonyl bisphenol. Ester-forming derivatives of diol include ethylene oxide.

The side chain type polyoxyalkylene group-containing comonomer gives a structural unit represented by the general formula (I), and includes, for example, polyoxyethylene glycol-methyl-glycidyl ether and polyoxyethylene glycol. -Methyl-2,3-dihydroxypropyl ether, polyoxyethylene glycol-ethyl-glycidyl ether, polyoxyethylene glycol-ethyl-
2,3-dihydroxypropyl ether, polyoxyethylene glycol-n-propyl-glycidyl ether, polyoxyethylene glycol-n-propyl-
2,3-dihydroxypropyl ether, polyoxyethylene glycol-t-butyl-glycidyl ether,
Polyoxyethylene glycol-t-butyl-2,3-
Dihydroxypropyl ether, polyoxyethylene glycol-n-octyl-glycidyl ether, polyoxyethylene glycol-n-octyl-2,3-dihydroxypropyl ether, polyoxyethylene glycol-2 -Ethylhexyl-glycidyl ether, polyoxyethylene glycol-2-ethylhexyl-2,
3-dihydroxypropyl ether, polyoxyethylene glycol-n-dodecyl-glycidyl ether, polyoxyethylene glycol-n-dodecyl-2,3-
Dihydroxypropyl ether, polyoxyethylene glycol-n-stearyl-glycidyl ether, polyoxyethylene glycol-n-stearyl-2,3-
Dihydroxypropyl ether, polyoxyethylene glycol-phenyl-glycidyl ether, polyoxyethylene glycol-phenyl-2,3-dihydroxypropyl ether, polyoxyethylene glycol-nonylphenyl-glycidyl ether Ter, polyoxyethylene glycol-nonylphenyl-2,3-dihydroxypropyl ether, polyoxyethylene glycol-cyclohexyl-glycidyl ether, polyoxyethylene glycol-cyclohexyl-2,3-dihydroxypropyl Ether, methyl-glycidyl ether of polyoxyethylene glycol / polyoxypropylene glycol copolymer, methyl-2,3 of polyoxyethylene glycol / polyoxypropylene glycol copolymer
N-propyl-glycidyl ether of dihydroxypropyl ether and polyoxyethylene glycol / polyoxypropylene glycol copolymer, n of polyoxyethylene glycol / polyoxypropylene glycol copolymer One or more kinds selected from -propyl-2,3-dihydroxypropyl ether and the like can be used.

The above-mentioned main chain type polyoxyalkylene group-containing comonomer gives the structural unit represented by the general formula (II), and includes, for example, polyoxyethylene glycol,
One or more of polyoxypropylene glycol, polyoxyethylene glycol / polyoxypropylene glycol copolymer and the like can be selected and used.

The above-mentioned comonomer containing a metal sulfonate group
Is to give a structural unit represented by the general formula (III), for example, 5-sodium sulfoisophthalic acid, 5-
Sodium sulfoisophthalic acid dimethyl ester, 5-
Sodium sulfoisophthalic acid diethyl ester, 5-
Metal sulfonate such as potassium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid dimethyl ester, 5-potassium sulfoisophthalic acid diethyl ester, 5-lithium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid dimethyl ester, 2-sodium sulfoterephthalic acid Benzenedicarboxylic acid or a lower alkyl ester thereof; 4-sodium sulfo-2,7-naphthalenedicarboxylic acid, 4-sodium sulfo-2,6-naphthalenedicarboxylic acid, 4-sodium sulfo-2,6
-Naphthalenedicarboxylic acid dimethyl ester, 6-sodium sulfo-1,4-naphthalenedicarboxylic acid, 5-
Metal sulfonated naphthalenedicarboxylic acids such as sodium sulfo-1,4-naphthalenedicarboxylic acid and the like and lower alkyl esters thereof and the like can be mentioned.

The above-mentioned copolymerized polyesters include known catalysts used for producing ordinary polyesters, for example, zinc compounds such as zinc acetate and zinc carbonate, manganese compounds such as manganese acetate and manganese carbonate, and calcium acetate. , Calcium compounds such as calcium carbonate, cobalt compounds such as cobalt acetate and cobalt carbonate, transesterification catalysts such as barium compounds such as barium acetate and barium carbonate; antimony compounds such as antimony oxide; germanium compounds such as germanium acetate; orthotitanic acid Polycondensation catalysts such as tetraisopropyl and titanium potassium oxalate are exemplified.

The above-mentioned copolymerized polyester contains optional additives as required, for example, coloring inhibitors, heat stabilizers, fluorescent bleaching agents, flame retardants, antioxidants, matting agents, coloring agents, and inorganic fine particles. It may be.

It is generally known that polyoxyalkylene is easily oxidized by oxygen in the air. Even in the above-mentioned copolymerized polyester, the polyoxyalkylene chain portion may be oxidized under high-temperature conditions such as polycondensation reaction or melt spinning conditions, which may cause inconveniences such as a decrease in the degree of polymerization and coloring of the fibers. It is preferable to add an antioxidant in order to obtain a fiber having good mechanical performance. Antioxidants can be classified into chain initiation inhibitors, radical chain inhibitors, peroxide decomposers, etc. according to their mechanism of action, but antioxidants classified as radical chain inhibitors are superior in terms of effect, and among them, However, a hindered phenol-based antioxidant is suitable. Such a hindered phenolic antioxidant is a phenolic compound having a sterically hindered substituent at both or one of two carbon atoms adjacent to the carbon atom having a phenolic hydroxyl group, Ir
ganox 1010 (manufactured by Ciba Geigy Corporation), Irga
nox1330 (manufactured by Ciba Geigy), Godrit
e3114 (manufactured by Goodrich) or the like can be used.

The above-mentioned hindered phenol antioxidants may be used alone or in combination of two or more. Further, they may be used in combination with other antioxidants, and are particularly classified into peroxide decomposers such as phosphorus antioxidants such as triphenyl phosphite and sulfur antioxidants such as dilauryl dithiopropionate. When an antioxidant is used in combination, a higher antioxidant effect may be obtained due to a synergistic effect with a hindered phenol-based antioxidant.

The amount of the hindered phenol-based antioxidant to be used is 0.2 to 0.2% of the total of the structural unit represented by the general formula (I) and the structural unit represented by the general formula (II).
Preferably, the amount is within the range of 20% by weight,
More preferably, the amount is in the range of 0.5 to 10% by weight. If the amount of the hindered phenol-based antioxidant is less than 0.2% by weight, the antioxidant effect of the resulting fiber may be insufficient. The antioxidant effect reaches saturation, and no remarkable improvement in the effect is observed. Conversely, troubles such as breakage of single yarn in the spinning process may be caused, and the mechanical performance of the obtained fiber may be reduced. The hindered phenolic antioxidant can be added until the above-mentioned polycondensation reaction of the copolymerized polyester is completed or at any stage after the completion.

Polymers other than the above-mentioned copolymerized polyester
The type is not particularly limited as long as it is physically or chemically different from the copolymerized polyester, but the polyamide-based polymer and the polyolefin-based polymer are compatible with the copolymerized polyester in terms of compatibility, adhesiveness, splitting property and the like. Is preferred. Specifically, nylon 6, nylon 66, nylon 6
10, meta-xylene diamine nylon, nylon 12,
Polypropylene, polyethylene, a random or block copolymer of polypropylene / polyethylene and the like can be applied.

In the present invention, a small amount of dyes, pigments, coloring inhibitors, ultraviolet absorbers, fluorescent brighteners, stabilizers, matting agents, foaming agents, flame retardants, antistatics An additive such as an agent may be contained.

The above copolymerized polyester and another polymer
In the case of producing easily splittable fibers from the two components of the above, a range of 15/85 to 85/15 (former / latter) in weight ratio can be applied as the composite ratio, but the weight ratio can be changed depending on the purpose. It is. For example, in order to impart excellent water absorption performance to a nonwoven fabric, the nonwoven fabric mainly contains the above-mentioned copolymerized polyester, that is, 30/70 to 85/15.
Is particularly preferred. Either polymer is 15
If the amount is less than the weight percentage, the spinnability may be poor, which is not preferable.

The easily splittable fiber in the present invention can be prepared by using each of the polymers including the above-mentioned copolymerized polyester,
It can be manufactured by a mixed spinning method described in, for example, Japanese Patent No. That is, each polymer is melt-extruded with two extruders, subdivided and mixed in a multi-layered form in a spinning pack, spun out from a die, stretched, crimped, heat-set, etc., and manufactured. Can be. Single yarn fineness is 1-1
It is preferably within the range of 2 denier. In particular, it is preferably in the range of 1 to 5 denier from the viewpoint of the feeling of the obtained nonwoven fabric. The cross-sectional shape of the easily splittable fiber obtained in this manner can be any cross-sectional shape such as a circular shape, a multi-leaf shape such as a three to eight-lobe shape, or a T-shape by selecting the shape of the nozzle to be used. And may be a solid fiber or a hollow fiber. Each polymer has a multilayer mixed structure such as a chrysanthemum flower shape, a multilayer bimetal shape, a sea-island shape, a nebula shape, etc. in the cross section of the fiber, and the entire cross section may be a multilayer mixed structure. The part may have a multilayer mixed structure. Further, the easily splittable fibers in the present invention preferably have fineness and different fineness by the splitting treatment, and it is preferable that the cross-sectional shapes of the split fine fibers are different from the viewpoint of entanglement, nonwoven fabric strength, feeling, and the like.

The easily splittable fiber obtained as described above is
For example, it is cut into a staple fiber by cutting into a length of 30 to 130 mm and passed through a card and a random web to obtain a fiber web such as a random web, a parallel web, and a cross wrap web. It is preferable that the fiber web is moved to the next processing step or the fiber is entangled by a needle punch method so as not to be deformed by the processing in the subsequent step. The punch density of the needle punch varies depending on the thickness of the fiber web, but may generally be in the range of 10 to 100 punches / cm ² . In some cases, it is not necessary to perform a needle punch on a thin fiber web. A high-pressure jet fluid stream is applied to at least one surface of the fiber sheet (non-woven fabric) obtained in this manner to perform entanglement of fibers, formation of fine fibers by splitting of fibers, formation of fine fibers of whiskers, and the like. Confound. Water is preferably used as the high-pressure jet fluid stream, and water at room temperature, water heated to about 35 to 80 ° C., or the like can be used, and may contain a treating agent for promoting fiber splitting and splitting. In addition, the water pressure is determined by the easiness of splitting and splitting the fiber.
g / cm ² . In the entanglement treatment of the fibers by the high-pressure jet fluid flow, the apparent density of the layer on the fiber sheet surface side in contact with the fluid flow is 0.03 g higher than the apparent density of the other surface side or the intermediate layer of the fiber sheet. / Cm ³ or more is preferable from the viewpoint of increasing the smoothness of the fiber sheet and imparting a firm feeling to the fiber sheet. For example, in the case of a fiber sheet treated on one side with a fluid flow, the apparent density of the layer on the contact surface side is 0.04 higher than the apparent density of the layer on the other surface side.
It is preferably at least 3 g / cm ³ higher, and in the case of a fiber sheet treated on both sides with a fluid flow, it is preferable that both layers are at least 0.03 g / cm ³ higher than the apparent density of the intermediate layer. . In order to give the fiber sheet a gradient of apparent density, the apparent density of the fiber sheet is 0.13.
g / cm ³ or more, particularly preferably 0.15 g / cm ³ or more.

In the above method for producing a fiber sheet, a thermal binder fiber containing a polymer having a relatively low softening temperature as a sheath component is mixed in a range of 5 to 40% by weight based on the nonwoven fabric. It is also possible to fix the fiber
This is preferable for applications requiring morphological stability.

The nonwoven fabric thus obtained is subjected to a smoothing treatment by bringing the surface where fibers are densely entangled into contact with a heated calendar, an embossing treatment by heating, dyeing, printing, etc. To give a product.

The layer on the side of the nonwoven fabric subjected to the high-pressure fluid flow treatment may be composed of fine fibers formed by partially splitting easily splittable fibers constituting the layer, or a combination of the fine fibers and the undivided fibers. Have a confounding state.

The basis weight of the nonwoven fabric varies depending on its use.
0 g / m ^2, the wiping textile sheet - DOO, wiping cloths, interlining clothes, sheets - Tsu, Te - Burukurosu, medical gowns, the base cloth of synthetic leather 30 to 200 g / m ^2, civil engineering and industrial materials For example, it is 50 to 2000 g / m ² . The nonwoven fabric of the present invention has an apparent density (ρ) and
It is necessary that the product of the wicking length (mm) after washing 0 times is 7, especially 10 or more. When the product is less than 7, the nonwoven fabric has poor durability and hydrophilicity, and is not suitable for the intended use.

A significant feature of the nonwoven fabric of the present invention is that the nonwoven fabric has such durability that the excellent water absorption performance hardly decreases even after the washing treatment. Usually, polyester fibers are provided with water absorbing performance by coating the surface thereof with various processing agents, treating agents, finishing agents and the like. For example, a polyvinyl alcohol-based treating agent, a polyether ether-based hydrophilic antifouling agent, a nonionic, anionic or cationic hydrophilic oil agent, or a combination thereof.
Nonwoven fabrics composed of fibers coated with these processing agents,
In any case, although the initial water absorption performance is slightly high, the performance is extremely reduced when the washing treatment is performed. On the other hand, it was confirmed that the nonwoven fabric of the present invention hardly reduced the water absorption performance after washing.

It is not clear why the nonwoven fabric of the present invention has excellent water-absorbing performance. However, the nonwoven fabric of the present invention has a partially divided fibrillated structure having a fine capillary effect and a non-woven fabric having excellent hydrophilicity. This is presumed to be due to the synergistic effect of using the polymerized polyester as one component.

The nonwoven fabric of the present invention can be used as a facing material for sanitary materials such as sanitary napkins, diapers and breast milk pads, a wiping fiber sheet, a wiping cloth, an interlining, a cotton pad, clothing,
It is useful for medical supplies such as disposable surgical gowns, sheets, tablecloths, covers, bags, civil engineering and industrial materials.

[0066]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. Each physical property value in the examples is a value obtained by measurement according to the following method.

(1) Intrinsic viscosity [η] (dl / g) of copolymerized polyester 0.25 g / dl, 0.5% of polyester in a mixed solvent of phenol and tetrachloroethane (weight ratio 1: 1)
The solution was dissolved at each concentration of 0 g / dl and 1.0 g / dl, and each solution was determined from three types of reduced viscosities measured at a temperature of 30 ° C.

(2) Wicking length L (mm) The water absorption length was measured by the Bayrex method. That is, raw cotton having a single yarn fineness of 2 denier and a cut length of 51 mm is carded,
A fiber web having an average basis weight of 60 g / m ² was put on a random weber, and ^two of them were laminated and subjected to a needle punch of 70 punches / cm ² with a needle of needle number # 40.
Obtain a fiber sheet. Then, using a high-pressure water jet nozzle in which nozzles with a hole diameter of 0.25 mm are arranged in a row,
0 kg / cm is gradually injected columnar water flow to 150 kg / cm ² from ^2, fiber sheet on a moving wire mesh support - on one side of the bets performs three-stage process, air dried, further O - Todoraiya - at What was heat-treated at 150 ° C. for 1 minute was used as a nonwoven fabric for measuring water absorption. The nonwoven fabric for measurement is suspended in a state of being partially immersed in water colored with red ink.
The wicking length after 0 minutes was measured. The measurement of the wicking length was performed in each of n = 10 in the vertical direction and the horizontal direction of the nonwoven fabric, and the value obtained by summing the average values of the vertical and horizontal directions was defined as the wicking length. The sample was washed according to JIS L0217-103. That is, 2 g of a synthetic detergent for clothing is added and dissolved in 1 liter of water at 40 ° C. to make a washing liquid. A sample and a load cloth are introduced into the washing liquid so that the bath ratio becomes 1:30, and the operation of the home washing machine is started. 5
After the treatment for one minute, the operation is stopped, the sample and the load cloth are dehydrated with a centrifugal dehydrator, and then the washing liquid is replaced with fresh water at room temperature, rinsed at the same bath ratio for two minutes, and then dehydrated. Again 2
Rinse for a minute and air dry. Perform the above operations for a total of 10
The sample after washing 10 times was obtained by repeating this process twice.

(3) Apparent density (g / cm ³ ) of nonwoven fabric The thickness (cm) of the nonwoven fabric was measured under a load of 20 g / cm ² , and the apparent weight (g / m ² ) was divided by the thickness. The density was used.

Examples 1 to 3 971.9 g of terephthalic acid, 40.2 g of 5-sodium sulfoisophthalic acid and 750 g of ethylene glycol
Was charged into an esterification reactor, and 2.5 kg /
The esterification reaction was performed under a pressure of cm ² for 3 hours. Next, the obtained reaction product was transferred to a polycondensation apparatus which had been heated to 230 ° C.

[0071]

Embedded image

The main chain type polyoxyalkylene group-containing compound represented by the formula HO- (CH ₂ CH ₂ O) ₄₅ -H is added in an amount shown in Table 1. And 5% by weight of 1, based on the total amount of these polyoxyalkylene group-containing compounds.
3,5-tris (4-t-butyl-3-hydroxy-
2,6-Dimethylbenzyl) -1,3,5-triazine-2,4,6- (1H, 3H, 5H) -trione [manufactured by American Cyanamid, Cyanox 179
0], 0.4 g of antimony trioxide, 0.12 g of phosphorous acid
And 0.29 g of an antifoaming agent were added to adjust the polycondensation reaction system. Raise the temperature of the polycondensation reaction system from 230 ° C to 280 ° C.
While the temperature was raised over 5 minutes, the pressure was gradually reduced to 0.3 mmHg. Thereafter, at 280 ° C., the melt viscosity of the system was changed to an intrinsic viscosity of 0.6.
By continuing the polycondensation reaction until the melt viscosity at 280 ° C. of 0 dl / g of polyethylene terephthalate almost coincides with each other, the corresponding copolymerized polyester is obtained, and the polyester is then crystallized at 150 ° C. under vacuum. Processed.

The obtained copolymerized polyester (A polymer) and intrinsic viscosity [η] in m-cresol at 30 ° C.
Using nylon-6 (B polymer) of 1.16, each polymer was melted and extruded separately and fed to the spinning head, and then the molten polymer A and B were mixed with the spinning head at A / B = 70.
/ 30 (weight ratio), joining and splitting were repeated 5 times by a static mixer, and the spinning temperature was 270.
The fiber was spun at ℃ to obtain easily splittable fibers having a cross-sectional shape similar to that of FIG. This fiber was drawn, crimped, and heat-set to obtain a drawn fiber having a fineness of single yarn of 2 denier. 51 mm of the obtained fiber
The fiber is cut into long staple fibers, and ^two fiber webs having an average basis weight of 60 g / m ² produced through a card and a random web are laminated, and are sewn with a needle of # 40 needle number 70.
Perform a needle punch of punch / cm ² , and
I got it. Then, using a high-pressure water jet nozzle in which nozzles having a hole diameter of 0.25 mm are arranged in a row, a water pressure of 30 kg was used.
/ Cm ² to 150 kg / cm ^2, and a three-stage treatment is performed on one side of the fiber sheet on the moving wire mesh support. The thickness is 0.508 mm and the apparent density is 0.236 g / cm 2. ³ was obtained.

In this nonwoven fabric, a large number of whisker-like fine fibers are generated on the surface subjected to the water flow treatment, and the undivided fibers and the divided fine fibers are in a densely entangled state.
The lower part of the surface, that is, the middle layer of the nonwoven fabric and most of the other surface layers were in an entangled state mainly due to the longitudinal orientation of the fibers. The thickness of the nonwoven fabric was sliced into approximately two portions with a band machine knife, and the apparent density of each was measured. The surface on which the water flow hit was 0.27 g / c.
m ³ , and 0.21 g / cm ³ on the other side. Next, the surface of the nonwoven fabric to which the water flow was applied was pressed against a calendar surface heated to 130 ° C. to perform a smoothing treatment. The final non-woven fabric is soft and drapable and has a cutting strength of 0.47.
It was as high as kg / mm ² and was suitable for uses such as clothing and tablecloths.

The wicking length of the obtained nonwoven fabric was set to the standard state (25
C., 65% RH). The results are shown in Table 2.
As is clear from Table 2, the nonwoven fabric of the present invention had good durability and good water absorption.

Examples 4 to 8 In Example 1, the corresponding side chain type polyoxyalkylene group-containing compounds represented by the following formulas were used as the side chain type polyoxyalkylene group-containing compounds constituting the A polymer. The corresponding copolymerized polyesters were obtained in the same manner except that only the amounts shown in the above were used. Comonomer used in Example 4:

Embedded image Comonomer used in Example 5:

Embedded image Comonomer used in Example 6:

Embedded image Comonomer used in Example 7:

Embedded image Comonomer used in Example 8:

Embedded image The obtained polyester and nylon 6 were spun in the same manner as in Example 1 and entangled with a high-pressure water stream to obtain a nonwoven fabric.
This nonwoven fabric was evaluated, and the results are shown in Table 2. In each case, the fiberization processability of easily splittable fibers was good, and the obtained nonwoven fabric had good water absorption.

Examples 9 and 10 In Example 1, as the main chain type polyoxyalkylene group-containing compound constituting the A polymer, the corresponding main chain type polyoxyalkylene group-containing compound represented by the following formula was used. The corresponding copolymerized polyesters were obtained in the same manner except that only the amounts shown in the above were used. Comonomers used in Example _{9 -: HO- (CH 2 CH} 2 O) comonomer used in ₂₀ -H Example 10 -: HO- and (CH ₂ CH ₂ O) ₇₀ Polyester and nylon 6 obtained -H Was spun in the same manner as in Example 1 and entangled with a high-pressure water stream to obtain a nonwoven fabric.
This nonwoven fabric was evaluated, and the results are shown in Table 2. In each case, the fiberization processability of easily splittable fibers was good, and the obtained nonwoven fabric had good water absorption.

Example 11 In Example 1, instead of 971.9 g of terephthalic acid and 40.2 g of 5-sodium sulfoisophthalic acid constituting the A polymer, terephthalic acid 986.
8 g and 5-sodium sulfoisophthalic acid 16.1
A corresponding copolymerized polyester was obtained in the same manner except that g was used. The obtained polyester and nylon 6 were spun in the same manner as in Example 1 and entangled with a high-pressure water stream to obtain a nonwoven fabric. This nonwoven fabric was evaluated, and the results are shown in Table 2.
In each case, the fiberization processability of easily splittable fibers was good, and the obtained nonwoven fabric had good water absorption.

Example 12 In Example 1, 941.9 g of terephthalic acid was used instead of 971.9 g of terephthalic acid and 40.2 g of 5-sodium sulfoisophthalic acid constituting the A polymer.
g and 5-sodium sulfoisophthalic acid 80.41
A corresponding copolymerized polyester was obtained in the same manner except that g was used. The obtained polyester and nylon 6 were spun in the same manner as in Example 1 and entangled with a high-pressure water stream to obtain a nonwoven fabric. This nonwoven fabric was evaluated, and the results are shown in Table 2.
In each case, the fiberization processability of easily splittable fibers was good, and the obtained nonwoven fabric had good water absorption.

Examples 13 and 14 In Example 1, the composite ratio of the A polymer and the B polymer was changed to 50/50 (Example 13) and 30/70 (Example 1).
Spinning was carried out in the same manner except for 4), and entangled in a high-pressure water stream to obtain a nonwoven fabric. This nonwoven fabric was evaluated, and the results are shown in Table 2.
Shown in Both have good fiberization processability of easily splittable fibers,
Moreover, the obtained nonwoven fabric had good water absorbency.

Examples 15 and 16 In Example 1, 1,4-butanediol 1 was replaced by 750 g of ethylene glycol constituting the A polymer.
089 g (Example 15), 1,6-hexanediol-1
A corresponding copolymerized polyester was obtained in the same manner except that 427 g (Example 16) was used. The obtained polyester and nylon 6 were spun in the same manner as in Example 1 and entangled with a high-pressure water stream to obtain a nonwoven fabric. This nonwoven fabric was evaluated, and the results are shown in Table 2. In each case, the fiberization processability of easily splittable fibers was good, and the obtained nonwoven fabric had good water absorption.

Examples 17 and 18 In Example 1, Nylon-12 having an intrinsic viscosity [η] of 1.0 in m-cresol at 30 ° C. as B polymer was used.
(Example 17) Spinning was performed in the same manner except that polypropylene having a melt index (MI) of 30 (Example 18) was used, and entangled with a high-pressure water stream to obtain a nonwoven fabric. This nonwoven fabric was evaluated, and the results are shown in Table 2. In each case, the fiberization processability of easily splittable fibers was good, and the obtained nonwoven fabric had good water absorption.

Example 19 Spinning was performed in the same manner as in Example 1 except that the cross-sectional shape of the easily splittable fiber was changed to FIG. 2A instead of FIG. To obtain a non-woven fabric. This nonwoven fabric was evaluated, and the results are shown in Table 2. In each case, the fiberization processability of easily splittable fibers was good, and the obtained nonwoven fabric had good water absorption.

Example 20 Separable fiber 75 having the same single yarn fineness of 2 denier as in Example 1
And a core of polyethylene terephthalate, and a sheath is an ester copolymer, and 25 parts of a core-sheath type heat binder fiber having a denier of 3 denier is mixed and averaged through a random webber. A fiber web having a basis weight of 25 g / m ² was obtained,
High pressure water flow treatment was performed on the support in the same manner as in Example 1 to produce a fiber-entangled nonwoven fabric having an apparent density of 0.28 g / cm ³ . Subsequently, the dense surface of the nonwoven fabric to which the water flow was applied was pressed against a heated calendar surface of 135 ° C. to perform smoothing treatment and bonding between the fibers by melting the heat binder fibers. The obtained nonwoven fabric was excellent in water absorption performance and was suitable as a facing material for sanitary napkins.

[0085]

[Table 1]

[0086]

[Table 2]

Comparative Example 1 A non-woven fabric was produced in the same manner as in Example 1 using a single staple fiber of polyethylene terephthalate having a single yarn fineness of 2 denier and a cut length of 51 mm, and the water absorption performance was measured. There was little sex.

Comparative Example 2 Spinning was performed in the same manner as in Example 1 except that polyethylene terephthalate was used instead of the copolymerized polyester as the A polymer, and the mixture was entangled with a high-pressure water stream to obtain a nonwoven fabric. This nonwoven fabric was evaluated, and the results are shown in Table 4. The water absorption of the nonwoven was at a very low level.

Comparative Example 3 A copolymerized polyester was obtained in the same manner as in Example 1 except that the compound containing a polyoxyalkylene group constituting the A polymer was not used at all. The obtained polyester and nylon 6 were spun in the same manner as in Example 1 and entangled with a high-pressure water stream to obtain a nonwoven fabric. This nonwoven fabric was evaluated, and the results are shown in Table 4. The water absorption of the nonwoven was at a very low level.

Comparative Example 4 A copolymerized polyester was obtained in the same manner as in Example 1 except that no side chain type polyoxyalkylene group-containing compound constituting the A polymer was used. The obtained polyester and nylon 6 were spun in the same manner as in Example 1 and entangled with a high-pressure water stream to obtain a nonwoven fabric. This nonwoven fabric was evaluated, and the results are shown in Table 4. The water absorption of the nonwoven was at a very low level.

Comparative Example 5 A copolymerized polyester was obtained in the same manner as in Example 1 except that the main chain type polyoxyalkylene group-containing compound constituting the A polymer was not used at all. The obtained polyester and nylon 6 were spun in the same manner as in Example 1 and entangled with a high-pressure water stream to obtain a nonwoven fabric. This nonwoven fabric was evaluated, and the results are shown in Table 4. The water absorption of the nonwoven was at a very low level.

Comparative Example 6 In Example 1, the corresponding side chain type polyoxyalkylene group-containing compound represented by the following formula was used as the side chain type polyoxyalkylene group-containing compound constituting the A polymer.
The corresponding copolymerized polyesters were obtained in the same manner except that only the amounts shown in (1) were used.

Embedded image The obtained polyester and nylon 6 were spun in the same manner as in Example 1, but the heat resistance during spinning was somewhat poor and the spinnability was poor. Also, immerse the obtained fiber in water,
When the dissolution property was measured with a TOC meter (TOC-500, manufactured by Shimadzu Corporation), the above-mentioned compound thought to be a side chain type polyoxyalkylene group-containing compound was eluted from the fiber, and the copolymerizability of the polyester was reduced. It turned out to be inadequate. The use as a commercial product was unsuitable due to the large amount of eluted substances from the fiber, and the evaluation as a nonwoven fabric did not occur.

Comparative Example 7 In Example 1, the corresponding side chain type polyoxyalkylene group-containing compound represented by the following formula was used as the side chain type polyoxyalkylene group-containing compound constituting the A polymer in Table 3.
The corresponding copolymerized polyesters were obtained in the same manner except that only the amounts shown in (1) were used.

Embedded image The obtained polyester and nylon 6 were spun in the same manner as in Example 1 and entangled with a high-pressure water stream to obtain a nonwoven fabric.
This nonwoven fabric was evaluated, and the results are shown in Table 4. The water absorption of the nonwoven was at a very low level.

Comparative Examples 8 and 9 In Example 1, the corresponding main chain type polyoxyalkylene group-containing compound represented by the following formula was used as the main chain type polyoxyalkylene group-containing compound constituting the A polymer in Table 3.
The corresponding copolymerized polyesters were obtained in the same manner except that only the amounts shown in the above were used. Comonomers used in Comparative Example _{8 -: HO- (CH 2 CH} 2 O) 5 comonomer used in -H Comparative Example 9 -: HO- and (CH ₂ CH ₂ O) ₂₀₀ polyester and nylon 6 obtained -H Was spun in the same manner as in Example 1 and entangled with a high-pressure water stream to obtain a nonwoven fabric.
This nonwoven fabric was evaluated, and the results are shown in Table 4. The coloration during the polymerization of the A polymer is intense, and there are many elutes from the fiber,
There was no evaluation as a nonwoven fabric.

Comparative Example 10 In Example 1, 30% by weight of the same side chain type polyoxyalkylene group-containing compound constituting the A polymer and 30% by weight of the same main chain type polyoxyalkylene group-containing compound were copolymerized. Polyester was obtained. The obtained polyester and nylon 6 were spun in the same manner as in Example 1, but single yarn breakage and breakage during spinning frequently occurred. Furthermore, since the stretchability was poor, the evaluation as a nonwoven fabric was not achieved.

Comparative Example 11 In Example 1, 881.9 g of terephthalic acid was used instead of 971.9 g of terephthalic acid and 40.2 g of 5-sodium sulfoisophthalic acid constituting the A polymer.
g and 5-sodium sulfoisophthalic acid 176.9
A corresponding copolymerized polyester was obtained in the same manner except that g was used. [Η] of the obtained polyester was 0.40.
dl / g. When the polyester and nylon 6 were spun in the same manner as in Example 1, single yarn breakage and breakage during spinning frequently occurred. Furthermore, since the stretchability was poor, the evaluation as a nonwoven fabric was not achieved.

[0097]

[Table 3]

[0098]

[Table 4]

[0099]

The nonwoven fabric of the present invention is composed of easily splittable fibers comprising at least two kinds of polymers including a polyester obtained by copolymerizing a specific compound in a specific amount, and at least one surface of the nonwoven fabric is easily split. The fibers are divided and split into fine fibers, and the fine fibers are finely entangled with each other or the fine fibers and the undivided fibers. It has excellent water absorption performance.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a cross section of a nonwoven fabric of the present invention, in which (a) is a nonwoven fabric in which one surface is densely entangled;
(B) is a nonwoven fabric in which both surfaces are densely entangled.

FIGS. 2A to 2C are representative cross-sectional views of easily splittable fibers constituting the nonwoven fabric of the present invention.

FIG. 3 is a perspective view illustrating a state of a fiber that has been split and split by an entanglement process.

[Explanation of symbols]

 1: non-woven fabric 2: densely entangled fiber layer 3: coarsely entangled fiber layer 4, 4 ': fine fiber component 5: undivided fiber portion 6: split and split fine fiber

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-269068 (JP, A) JP-A-4-91224 (JP, A) JP-A-4-136251 (JP, A) 370256 (JP, A) JP-A-5-51818 (JP, A) JP-A-4-13690 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) D04H 1/00-18 / 00 D01F 6/86 D01F 8/14

Claims (1)

(57) [Claims] 1. A non-woven fabric which satisfies the following formula (1), wherein an easily splittable fiber comprising two or more kinds of polymers which are physically or chemically different from each other is used as a main constituent fiber. One component is mainly a dicarboxylic acid unit,
Diol unit, general formula (I) [In the formula, x and y each represent 0 or 1, and Z represents a formula -O- (R ₂ -O) n ₁ -R ₁ (wherein, R ₁ has 1 to ₁ carbon atoms.
Represents a hydrocarbon group of 18, R ₂ represents an alkylene group,
n ₁ is a number of 10 to 100 representing an average degree of polymerization) and a monovalent group represented by the following general formula (II) —O— (R ₃ —O) n ₂ — ( In the formula, R ₃ represents an alkylene group, n ₂ is a number of 10 to 100 representing an average degree of polymerization, and a general formula (II
I) (Wherein, Ar represents a trivalent aromatic group and M represents a metal atom), and the content of the structural units represented by the general formulas (I) and (II) is as follows: Each is 1 to 49% by weight, and the total content of the structural units represented by the general formulas (I) and (II) is 2 to 50%.
% By weight, the content of the structural unit represented by the general formula (III) is 0 to 10 mol% with respect to all the acid components constituting the copolymerized polyester, and the intrinsic viscosity is 0.5 d.
A nonwoven fabric having excellent water absorbability, which is a copolymerized polyester having a l / g or more. L × ρ ≧ 7 (1) [where L is the wicking length (mm) after washing 10 times,
Is the apparent density (g / cm ³ ) of the nonwoven fabric]