JP2009209506A - Elastic nonwoven fabric and textile product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastic nonwoven fabric having excellent elastic recovery, being nonsticky, and having a pleasant texture, and to provide textile products using the elastic nonwoven fabric. <P>SOLUTION: The elastic nonwoven fabric is made of a sheath-core conjugate fiber comprising a lowly crystalline polypropylene satisfying the followings: (a) [mmmm]=20-60 mol%, (b) [rrrr]/(1-[mmmm])≤0.1, (c) [rmrm]>2.5 mole%, (d) [mm]×[rr]/[mr]<SP>2</SP>≤2.0, (e) weight average molecular weight (Mw)=10,000-200,000, and (f) molecular weight distribution (Mw/Mn)<4. The textile product comprises the elastic nonwoven fabric. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an elastic nonwoven fabric that has excellent elastic recovery properties, has no stickiness, and has a good touch, and a textile product using the elastic nonwoven fabric.

In recent years, elastic fibers and elastic nonwoven fabrics have been used for various uses such as disposable diapers, sanitary products, sanitary products, clothing materials, bandages, and packaging materials. Disposable diapers, sanitary products, etc. are used in direct contact with the body. Therefore, from the viewpoints of a good fit on the body and ease of movement of the body after wearing, moderate elasticity and elastic recovery Is required.
Patent Document 1 discloses an elastic fiber obtained by blending an elastomer such as an olefin copolymer or a styrene block copolymer and another resin component as an elastic fiber to which elastic resilience is imparted. However, since these elastomers are incompatible with polypropylene and are non-crystalline, when these elastomers and polypropylene are mixed to form elastic fibers, the elastomers bleed on the fiber surface. Therefore, the elastic nonwoven fabric made of this elastic fiber has a sticky feeling, and the fiber product using this elastic nonwoven fabric has a problem that the touch is bad.
Patent Document 2 discloses that a propylene polymer constituting a nonwoven fabric is treated with a free radical initiator. Such treatment improves the fluidity of the propylene polymer, but reduces the thermal stability of the propylene polymer.
Patent Document 3 discloses a sheath-core type composite fiber in which fibers are formed with a propylene composition composed of propylene and ethylene, and a propylene composition composed of propylene and ethylene as a sheath component and high-density polyethylene as a core component. It is disclosed to form. However, the propylene composition composed of propylene and ethylene is not necessarily sufficiently compatible with the crystalline isotactic propylene homopolymer, and there is a concern that the kneading property may be deteriorated or the physical properties may be decreased due to bleeding on the fiber surface. The

JP 2003-129330 A JP-T-2007-511680 JP 2007-277755 A

  The present invention has been made in view of the above circumstances, and has an object to provide an elastic nonwoven fabric that has excellent elastic recovery, is not sticky, has a good touch, and a textile product using the elastic nonwoven fabric. is there.

As a result of intensive studies, the present inventors have found that the above object can be achieved by an elastic nonwoven fabric composed of a core-sheath type composite fiber containing a specific low crystalline polypropylene. That is, it has been found that a core-sheath type composite fiber containing a low crystalline polypropylene having a specific stereoregularity is excellent in elastic recoverability, has reduced stickiness, and is suitable as a material for forming an elastic nonwoven fabric. The present invention has been completed based on such findings.
That is, the present invention provides the following elastic nonwoven fabric and a fiber product using the elastic nonwoven fabric.
(1) An elastic nonwoven fabric comprising a core-sheath composite fiber containing a low crystalline polypropylene satisfying the following (a) to (f):
(A) [mmmm] = 20-60 mol%
(B) [rrrr] / (1- [mmmm]) ≦ 0.1
(C) [rmrm]> 2.5 mol%
(D) [mm] × [rr] / [mr] ² ≦ 2.0
(E) Weight average molecular weight (Mw) = 10,000 to 200,000
(F) Molecular weight distribution (Mw / Mn) <4
(2) The sheath component contains 50 to 99% by mass of low crystalline polypropylene and 1 to 50% by mass of high crystalline polypropylene, and the core component is 90 to 100% by mass of low crystalline polypropylene and 0 to 10 The elasticity as described in (1) above, which comprises a core-sheath type composite fiber containing mass% highly crystalline polypropylene and containing a low crystalline polypropylene whose core component is higher than the sheath component. Non-woven,
(3) The elastic nonwoven fabric according to (1), wherein the total low crystalline polypropylene content calculated by the following formula is a core-sheath type composite fiber having a mass ratio of 90% to 99% by mass. ,
Total low crystalline polypropylene content = (Ws × Xs + Wc × Xc) / 100
Ws: Mass fraction of sheath component Wc: Mass fraction of core component Xs: Mass fraction of low crystalline polypropylene in sheath component Xc: Mass fraction of low crystalline polypropylene in core component (4) (1)-The textiles using the elastic nonwoven fabric in any one of (3).

  ADVANTAGE OF THE INVENTION According to this invention, while having the outstanding elastic recovery property, there is no stickiness and it can provide the elastic nonwoven fabric with favorable touch. Furthermore, the elastic nonwoven fabric has excellent performance such as good release from a take-up roll, excellent secondary processability, excellent heat resistance, and no shrinkage even when HMA (hot melt adhesive) is applied. Have

The elastic nonwoven fabric of this invention consists of a core-sheath-type composite fiber containing the low crystalline polypropylene which has a specific property.
In this specification, the core-sheath type composite fiber refers to a fiber whose cross section is composed of a “core” in the center and a “sheath” in the outer layer. Crystalline polypropylene refers to polypropylene whose melting point is observed by measurement using the following differential scanning calorimeter (DSC), and highly crystalline polypropylene refers to crystalline polypropylene having a melting point of 155 ° C. or higher. A low crystalline polypropylene means a crystalline polypropylene having a melting point of 0 to 120 ° C.
The melting point (Tm-D) is a melting endothermic curve obtained by using a differential scanning calorimeter (DSC) by holding at −10 ° C. for 5 minutes in a nitrogen atmosphere and then raising the temperature at 10 ° C./min. Is defined as the peak top of the peak observed on the hottest side.

[Low crystalline polypropylene]
The low crystalline polypropylene used in the present invention has the properties shown in the following (a) to (f), and these should be adjusted according to the selection of the catalyst and reaction conditions when producing the low crystalline polypropylene. Can do.

(A) Mesopentad fraction [mmmm] = 20-60 mol%
If the mesopentad fraction [mmmm] is less than 20 mol%, the solidification is very slow, so that the nonwoven fabric adheres to the calender roll or belt or is drawn and cannot be continuously formed. On the other hand, if the mesopentad fraction [mmmm] is greater than 60 mol%, the crystallinity is too high, and the elastic recovery is poor. The mesopentad fraction [mmmm] is preferably 30 to 50 mol%, more preferably 40 to 50 mol%.

(B) [rrrr] / [1-mmmm] ≦ 0.1
The value of [rrrr] / [1-mmmm] is an index indicating the uniformity of the regularity distribution of the low crystalline polypropylene. When this value becomes large, it becomes a mixture of highly ordered polypropylene and atactic polypropylene like conventional polypropylene produced using a magnesium-supporting titanium catalyst, which causes stickiness.
In the above low crystalline polypropylene, if [rrrr] / [1-mmmm] is larger than 0.1, the regularity distribution is widened to form a mixture of atactic polypropylene, which causes stickiness. From such a viewpoint, [rrrr] / (1- [mmmm]) is preferably 0.05 or less, more preferably 0.04 or less.

(C) [rmrm]> 2.5 mol%
When the racemic meso racemic meso fraction [rmrm] of the low crystalline polypropylene is 2.5 mol% or less, the randomness of the low crystalline polypropylene is reduced, the crystallinity is increased, and the elastic recovery property is lowered. . [Rmrm] is preferably 2.6 mol% or more, more preferably 2.7 mol% or more. The upper limit is usually about 10 mol%.

(D) [mm] × [rr] / [mr] ² ≦ 2.0
[Mm] × [rr] / [mr] ² represents an index of randomness of the polymer, and the closer to 0.25, the higher the randomness and the better the elastic recovery. When this value is 2.0 or less, sufficient elastic recovery is obtained in the fiber obtained by spinning, and stickiness is also suppressed.
From the viewpoint of obtaining sufficient elastic recovery, [mm] × [rr] / [mr] ² is preferably 0.25 to 1.8, more preferably 0.25 to 1.5.

(E) Weight average molecular weight (Mw) = 10,000 to 200,000
When the weight average molecular weight is 10,000 or more in the low crystalline polypropylene, the viscosity of the low crystalline polypropylene is not too low and is moderate, so that yarn breakage during spinning is suppressed. Moreover, when the weight average molecular weight is 200,000 or less, the viscosity of the low crystalline polypropylene is not too high, and the spinnability is improved. This weight average molecular weight is preferably 30,000 to 150,000, and more preferably 50,000 to 150,000.

(F) Molecular weight distribution (Mw / Mn) <4
In the low crystalline polypropylene, when the molecular weight distribution (Mw / Mn) is less than 4, occurrence of stickiness in the fiber obtained by spinning is suppressed. This molecular weight distribution is preferably 3 or less.

The stereoregularity of the above (a) to (d) is determined by NMR.
In the present invention, the mesopentad fraction [mmmm], the racemic pentad fraction [rrrr], and the racemic meso racemic meso pendad fraction [rmrm] are determined by A. Zambelli et al., “Macromolecules, 6,925 ( 1973) ”, and meso fraction, racemic fraction, and racemic meso-racemic meso fraction in pentad units in a polypropylene molecular chain measured by a signal of a methyl group in a ¹³ C-NMR spectrum. It is. As the mesopentad fraction [mmmm] increases, the stereoregularity increases. The triad fractions [mm], [rr] and [mr] were also calculated by the above method.
The measurement of the ¹³ C-NMR spectrum can be carried out with the following apparatus and conditions in accordance with the attribution of the peak proposed in “Macromolecules, 8, 687 (1975)” by A. Zambelli et al. it can.

Apparatus: JNM-EX400 type ¹³ C-NMR apparatus manufactured by JEOL Ltd. Method: Proton complete decoupling method Concentration: 220 mg / ml
Solvent: 90:10 (volume ratio) mixed solvent of 1,2,4-trichlorobenzene and heavy benzene Temperature: 130 ° C
Pulse width: 45 °
Pulse repetition time: 4 seconds Integration: 10,000 times

<Calculation formula>
M = m / S × 100
R = γ / S × 100
S = Pββ + Pαβ + Pαγ
S: Signal intensity of side chain methyl carbon atoms of all propylene units Pββ: 19.8 to 22.5 ppm
Pαβ: 18.0 to 17.5 ppm
Pαγ: 17.5 to 17.1 ppm
γ: Racemic pentad chain: 20.7 to 20.3 ppm
m: Mesopentad chain: 21.7-22.5 ppm

  Said (e) weight average molecular weight (Mw) and (f) molecular weight distribution (Mw / Mn) are calculated | required by a gel permeation chromatography (GPC) measurement. The weight average molecular weight of the present invention is a polystyrene-converted weight average molecular weight measured with the following apparatus and conditions, and the molecular weight distribution is a value calculated from the number average molecular weight (Mn) measured in the same manner and the above weight average molecular weight. is there.

<GPC measurement device>
Column: TOSO GMHHR-H (S) HT
Detector: RI detector for liquid chromatogram WATERS 150C
<Measurement conditions>
Solvent: 1,2,4-trichlorobenzene Measurement temperature: 145 ° C
Flow rate: 1.0 ml / min Sample concentration: 2.2 mg / ml
Injection volume: 160 μl
Calibration curve: Universal Calibration
Analysis program: HT-GPC (Ver.1.0)

The low crystalline polypropylene can be produced using, for example, a metallocene catalyst as described in WO2003 / 087172. In particular, those using a transition metal compound in which a ligand forms a cross-linked structure via a cross-linking group are preferred, and in particular, a transition metal compound that forms a cross-linked structure via two cross-linking groups and Metallocene catalysts obtained by combining promoters are preferred.
For example,
(A) General formula (I)

[In the formula, M represents a group 3-10 of the periodic table or a lanthanoid series metal element, and E ¹ and E ² represent a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a heterocyclopentadienyl group, respectively. A ligand selected from a substituted heterocyclopentadienyl group, an amide group, a phosphide group, a hydrocarbon group, and a silicon-containing group, which forms a cross-linked structure through A ¹ and A ² They may be the same or different from each other, X represents a sigma-binding ligand, and when there are a plurality of X, the plurality of X may be the same or different, and other X, E ¹ , It may be cross-linked with E ² or Y. Y represents a Lewis base, and when there are a plurality of Y, the plurality of Y may be the same or different, and may be cross-linked with other Y, E ¹ , E ² or X, and A ¹ and A ² are A divalent bridging group that binds two ligands, a hydrocarbon group having 1 to 20 carbon atoms, a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing group, a germanium-containing group, a tin-containing group , -O -, - CO -, - S -, - SO 2 -, - Se -, - NR 1 -, - PR 1 -, - P (O) R 1 -, - BR 1 - or -AlR ¹ - R ¹ represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms or a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, which may be the same as or different from each other. q represents an integer of 1 to 5 and represents [(M valence) -2], and r represents an integer of 0 to 3. ]
And (B) (B-1) a compound capable of reacting with the transition metal compound of component (A) or a derivative thereof to form an ionic complex, and (B-2) an aluminoxane. And a polymerization catalyst containing a component selected from:

  As the transition metal compound of the component (A), the ligand is preferably a (1,2 ′) (2,1 ′) double-bridge type transition metal compound, for example, (1,2′-dimethylsilylene) ( 2,1'-dimethylsilylene) -bis (3-trimethylsilylmethylindenyl) zirconium dichloride.

  Specific examples of the compound of the component (B-1) include triethylammonium tetraphenylborate, tri-n-butylammonium tetraphenylborate, trimethylammonium tetraphenylborate, tetraethylammonium tetraphenylborate, methyl tetraphenylborate (tri- n-butyl) ammonium, benzyl tetraphenylborate (tri-n-butyl) ammonium, dimethyldiphenylammonium tetraphenylborate, triphenyl (methyl) ammonium tetraphenylborate, trimethylanilinium tetraphenylborate, methylpyridinium tetraphenylborate, tetra Benzylpyridinium phenylborate, methyl tetraphenylborate (2-cyanopyridinium), trikis (tetrafluorophenyl) borate triethyla Monium, tetrakis (pentafluorophenyl) borate tri-n-butylammonium, tetrakis (pentafluorophenyl) triphenylammonium borate, tetrakis (pentafluorophenyl) borate tetra-n-butylammonium, tetrakis (pentafluorophenyl) tetraethylammonium borate Benzyl tetrakis (pentafluorophenyl) ammonium borate (tri-n-butyl), methyldiphenylammonium tetrakis (pentafluorophenyl) borate, triphenyl (methyl) ammonium tetrakis (pentafluorophenyl) borate, tetrakis (pentafluorophenyl) boric acid Methylanilinium, tetrakis (pentafluorophenyl) dimethylanilinium borate, tetrakis (pentafluorophenyl) L) Trimethylanilinium borate, methyl pyridinium tetrakis (pentafluorophenyl) borate, benzylpyridinium tetrakis (pentafluorophenyl) borate, methyl tetrakis (pentafluorophenyl) borate (2-cyanopyridinium), benzyl tetrakis (pentafluorophenyl) borate (2-cyanopyridinium), methyl tetrakis (pentafluorophenyl) borate (4-cyanopyridinium), triphenylphosphonium tetrakis (pentafluorophenyl) borate, tetrakis [bis (3,5-ditrifluoromethyl) phenyl] dimethylaniline borate Ferrocenium tetraphenylborate, silver tetraphenylborate, trityl tetraphenylborate, tetraphenylporphyrin manganese tetraphenylborate, Ferrocenium tetrakis (pentafluorophenyl) borate, tetrakis (pentafluorophenyl) borate (1,1′-dimethylferrocenium), tetrakis (pentafluorophenyl) decamethylferrocenium borate, silver tetrakis (pentafluorophenyl) borate, Tetrakis (pentafluorophenyl) triborate borate, tetrakis (pentafluorophenyl) lithium borate, tetrakis (pentafluorophenyl) sodium borate, tetrakis (pentafluorophenyl) borate Teolaphenyl porphyrin manganese, silver tetrafluoroborate, silver hexafluorophosphate, hexa Examples thereof include silver fluoroarsenate, silver perchlorate, silver trifluoroacetate, and silver trifluoromethanesulfonate.

  Examples of the aluminoxane as the component (B-2) include known chain aluminoxanes and cyclic aluminoxanes.

Also, trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, dimethylaluminum chloride, diethylaluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, dimethylaluminum fluoride, diisobutylaluminum hydride, diethylaluminum hydride, ethylaluminum sesquichloride, etc. A low crystalline polypropylene may be produced by using the organoaluminum compound in combination.
[Highly crystalline polypropylene]
As the highly crystalline polypropylene used in the present invention, Y2000GP (trade name, manufactured by Prime Polymer Co., Ltd.) can be used, and any crystalline polypropylene having a melting point of 155 ° C. or higher may be used. Not. For example, a propylene homopolymer, a propylene random copolymer, a propylene block copolymer, etc. are mentioned. The molecular weight of the highly crystalline polypropylene was selected from the viewpoint of moldability in all cases, and in the case of molding by the melt blow method, it was measured in accordance with JIS K7210 at a temperature of 230 ° C. and a load of 21.18 N. A melt flow rate (MFR) of about 100 to 2000 g / 10 min is preferred, and in the case of molding by the spunbond method, a melt flow rate (MFR) of about 10 to 100 g / 10 min is preferred. From these ranges, it can select and use by the intended use of a fiber or a nonwoven fabric. Specifically, for applications in which moldability is important, polypropylene having a high crystallization temperature and high crystallinity is preferable, and one having a crystallization temperature (Tc) of 100 ° C. or higher is more preferable.

[Core-sheath type composite fiber]
1. Sheath component The sheath component of the core-sheath type composite fiber preferably contains low crystalline polypropylene and high crystalline polypropylene, and the preferred component amounts are 50 to 99 mass% of low crystalline polypropylene and 1 to 1 of high crystalline polypropylene. 50% by mass, more preferably 60 to 95% by mass of low crystalline polypropylene and 5 to 40% by mass of high crystalline polypropylene, and still more preferably 60 to 90% by mass of low crystalline polypropylene and 10 to 10% of high crystalline polypropylene. 40% by mass. When the low crystalline polypropylene is 50% by mass or more, sufficient elastic recovery is obtained, and when it is 99% by mass or less, adhesion to the calender roll is suppressed and continuous moldability is improved.

  An internal mold release agent may be added to the sheath component of the present invention. An internal mold release agent is an additive that is added to a resin raw material to improve the peelability of a nonwoven fabric. Specifically, a high melting point polymer, an organic carboxylic acid or a metal salt thereof, an aromatic sulfonic acid or a metal thereof. Examples thereof include salts, organophosphate compounds or metal salts thereof, dibenzylidene sorbitol or derivatives thereof, rosin acid partial metal salts, inorganic fine particles, imides, amides, quinacridones, quinones, and mixtures thereof.

Examples of the high melting point polymer include polyolefins such as polyethylene and polypropylene.
Examples of organic carboxylic acids include octylic acid, palmitic acid, lauric acid, stearic acid, behenic acid, montanic acid, 12-hydroxystearic acid, oleic acid, isostearic acid, linoleic acid and other fatty acids such as benzoic acid, pt-butyl. -Aromatic carboxylic acids such as benzoic acid. Examples of the metal salt of organic carboxylic acid include salts of Li, Ca, Ba, Zu, Mg, Al, Pb and the like of the above organic carboxylic acid, and metal soaps that are metal salts of carboxylic acid, and specifically, benzoic acid. Examples thereof include aluminum salts, aluminum salts of pt-butylbenzoate, sodium adipate, sodium thiophenecarboxylate, sodium pyrolecarboxylate and the like.

  Examples of the aromatic sulfonic acid include linear alkyl benzene sulfonic acid, branched alkyl benzene sulfonic acid, naphthalene sulfonic acid, dodecyl benzene sulfonic acid and the like, and examples of the metal salt of the aromatic sulfonic acid include Li and Ca of the above aromatic sulfonic acid. , Ba, Zu, Mg, Al, Pb and the like.

  Examples of the organic phosphate compound include trimethyl phosphate, triethyl phosphate, tributyl phosphate, 2-ethylhexyl phosphate, butoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, Cresyl di 2,6-xylenyl phosphate, resorcinol diphenol phosphate, various aromatic condensed phosphates, 2-chloroethyl phosphate, chloropropyl phosphate, dichloropropyl phosphate, tribromoneopentyl phosphate, halogen-containing condensed phosphate, bis 2-ethylhexyl phosphate, diisodecyl phosphate, 2-methacryloyloxyethyl Acid phosphate, diphenyl-2-methacryloyloxyethyl phosphate, methyl acid phosphate, butyl acid phosphate, monoisodecyl phosphate, 2-butylhexyl acid phosphate, isodecyl acid phosphate, triphenyl phosphate, dibutyl hydrogen phosphate, dibutyl hydrogen phosphate , Polyoxyethylene lauryl ether phosphoric acid, polyoxyalkyl ether phosphoric acid, polyoxyethylene alkyl phenyl ether phosphoric acid, polyoxyethylene dialkyl phenyl ether phosphoric acid and the like. Examples of the phosphoric acid compound include Li, Ca, Ba, Zu, Mg, Al, and Pb. Examples of these commercially available products include ADK STAB NA-11 and ADK STAB NA-21 manufactured by ADEKA Corporation.

  Examples of dibenzylidene sorbitol or derivatives thereof include dibenzylidene sorbitol, 1,3: 2,4-bis (o-3,4-dimethylbenzylidene) sorbitol, 1,3: 2,4-bis (o-2,4- Dimethylbenzylidene) sorbitol, 1,3: 2,4-bis (o-4-ethylbenzylidene) sorbitol, 1,3: 2,4-bis (o-4-chlorobenzylidene) sorbitol and 1,3: 2,4 -Dibenzylidene sorbitol etc. are mentioned, As a commercial item, the Nippon All-Rika Co., Ltd. gel all MD, gel all MD-R, etc. are mentioned.

  Examples of the rosin acid partial metal salt include Pine Crystal KM1600, Pine Crystal KM1500, and Pine Crystal KM1300 manufactured by Arakawa Chemical Industries, Ltd.

  As inorganic fine particles, talc, clay, mica, asbestos, glass fiber, glass flake, glass beads, calcium silicate, montmorillonite, bentonite, graphite, aluminum powder, alumina, silica, diatomaceous earth, titanium oxide, magnesium oxide, pumice stone Examples thereof include powder, pumice balloon, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, dolomite, calcium sulfate, potassium titanate, barium sulfate, calcium sulfite, and molybdenum sulfide. Examples of these commercially available products include silicia manufactured by Fuji Silysia Co., Ltd., and Mizukasil manufactured by Mizusawa Chemical Industry Co., Ltd.

  These internal mold release agents can be used individually by 1 type or in combination of 2 or more types. In the present invention, among these internal mold release agents, dibenzylidene sorbitol, 1,3: 2,4-bis (o-3,4-dimethylbenzylidene) sorbitol, 1,3: 2,4-bis (o -2,4-dimethylbenzylidene) sorbitol, 1,3: 2,4-bis (o-4-ethylbenzylidene) sorbitol, 1,3: 2,4-bis (o-4-chlorobenzylidene) sorbitol and 1, 3: 2,4-dibenzylidene sorbitol is preferred.

  It is preferable that content of an internal mold release agent is 10-10000 mass ppm on the basis of a composition of sheath component resin, and 100-5000 mass ppm is more preferable. When the content of the internal mold release agent is 10 mass ppm or more, the function as a mold release agent is expressed, and when it is 10000 mass ppm or less, the balance between the function as the mold release agent and the economical efficiency is improved.

2. Core component The core component of the core-sheath composite fiber preferably contains low crystalline polypropylene, and the preferred component amounts are 90 to 100% by mass of low crystalline polypropylene and 0 to 10% by mass of high crystalline polypropylene. When the low crystalline polypropylene is 90% by mass or more, sufficient elastic recovery is obtained, and in order to obtain the highest elastic recovery, the low crystalline polypropylene is preferably 100% by mass.

3. Composite fiber The core-sheath type composite fiber of the present invention preferably satisfies the following rules. In addition, in the following description, it abbreviates as follows.
Ws: Mass fraction of sheath component Wc: Mass fraction of core component Xs: Mass fraction of low crystalline polypropylene in sheath component Xc: Mass fraction of low crystalline polypropylene in core component

  In the core-sheath type composite fiber of the present invention, the ratio of the sheath component to the core component (Ws / Wc) is preferably in the range of 50/50 to 10/90. Satisfactory elastic recovery is exhibited by satisfying the regulations.

  In the core-sheath type composite fiber of the present invention, the core component preferably contains a low crystalline polypropylene having a higher content than the sheath component. That is, Wc × Xc is preferably larger than Ws × Xs. By being such a core-sheath type composite fiber, both high elastic recovery and good continuous formability can be achieved.

In the core-sheath type composite fiber of the present invention, the total low crystalline polypropylene content calculated by the following formula is preferably 90 to 99% by mass. When it is 90% by mass or more, sufficient elastic recovery is obtained, and when it is 99% by mass or less, the formability due to adhesion to the calender roll can be deteriorated and stickiness of the nonwoven fabric can be avoided.
Total low crystalline polypropylene content = (Ws × Xs + Wc × Xc) / 100
The mass fraction of the sheath component and the mass fraction of the core component can be controlled by adjusting the resin discharge rate of the core portion and the sheath portion in the core-sheath composite nozzle used for nonwoven fabric molding.

  Various additives can be added to the sheath component and the resin composition of the core component used in the production of the core-sheath-type conjugate fiber of the present invention as necessary. Examples of the additive include an antioxidant, a neutralizing agent, a slip agent, an antiblocking agent, an antifogging agent, and an antistatic agent. These additives may be used individually by 1 type, and may be used in combination of 2 or more types. For example, examples of the antioxidant include phosphorus-based antioxidants, phenol-based antioxidants, and sulfur-based antioxidants. These may be added during the preparation of the resin composition of the sheath component and the core component, or may be added during the production of the low crystalline polypropylene.

[Elastic nonwoven fabric and textile products]
The elastic nonwoven fabric of this invention can be manufactured by methods, such as a melt blow method and a spun bond method, and a manufacturing method can be suitably selected according to the use of an elastic nonwoven fabric.
In the melt-blowing method, an elastic nonwoven fabric is produced by extruding a resin melt from a nozzle and then bringing it into contact with a high-speed heated gas stream to form fine fibers, which are collected on a moving collection surface and made into a nonwoven fabric. can do. The nonwoven fabric produced by the melt blow method has a good texture because the average diameter of the fibers constituting the nonwoven fabric is small.
In the spunbond method, continuous melted fibers are formed by spinning, stretching and opening the melt-kneaded resin, and the continuous continuous fibers are continuously deposited on the moving collection surface in a continuous process. An elastic nonwoven fabric is manufactured. In the spunbond method, an elastic nonwoven fabric can be produced continuously, and the elastic nonwoven fabric produced by the spunbond method has a high strength because the fibers constituting the nonwoven fabric are continuous long fibers.

  Although it does not specifically limit as a fiber product using the elastic nonwoven fabric of this invention, For example, the following fiber products can be mentioned. That is, disposable diaper members, elastic members for diaper covers, elastic members for sanitary products, elastic members for hygiene products, elastic tapes, adhesive bandages, elastic members for clothing, insulation materials for clothing, heat insulation materials for clothing, Protective clothing, hat, mask, gloves, supporter, elastic bandage, poultice base fabric, anti-slip base fabric, vibration absorber, finger sack, clean room air filter, electret processed electret filter, separator, insulation , Coffee bags, food packaging materials, automotive ceiling skin materials, soundproof materials, cushion materials, speaker dustproof materials, air cleaner materials, insulator skins, backing materials, adhesive nonwoven fabric sheets, door trims and other automotive parts, copying machine cleaning Various cleaning materials such as wood, surface and backing materials for carpets, agricultural distribution, wood drain , Mention may be made of shoes for members such as sports shoes skin, a bag member, industrial sealing material, such as wiping material and sheets.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

Example 1
(1) Production of Low Crystalline Polypropylene A stainless steel reactor with an internal volume of 20 L equipped with a stirrer was mixed with 20 L / h of n-heptane, 15 mmol / h of triisobutylaluminum, and dimethylanilinium tetrakispentafluorophenylborate ( 1,2'-dimethylsilylene) (2,1'-dimethylsilylene) -bis (3-trimethylsilylmethylindenyl) zirconium dichloride, triisobutylaluminum and propylene are contacted in advance at a mass ratio of 1: 2: 20. The catalyst component thus obtained was continuously supplied at 6 μmol / h in terms of zirconium.
The polymerization temperature was set to 67 ° C., and propylene and hydrogen were continuously supplied so that the hydrogen concentration in the gas phase of the reactor was 2 mol% and the total pressure in the reactor was maintained at 0.8 MPa · G. A polymerization reaction was performed.
By adding Irganox 1010 (manufactured by Ciba Specialty Chemicals) as a stabilizer to the obtained polymerization solution so that the content ratio is 500 ppm by mass, and then removing n-heptane as a solvent, A low crystalline polypropylene was obtained.
About the obtained low crystalline polypropylene, melting point (Tm-D), stereoregularity index ([mm]), mesopentad fraction [mmmm], racemic meso racemic meso fraction [rmrm], [rrrr] ] / (1- [mmmm]), [mm] × [rr] / [mr] ² , weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) were measured. The results are shown in Table 1.

(2) Molding of elastic nonwoven fabric As a sheath component, a melt flow rate (measured under conditions of a temperature of 230 ° C. and a load of 21.18 N in accordance with JIS K7210, 60% by mass of the low crystalline polypropylene obtained in (1) above) A highly crystalline polypropylene (MFR, Y2000GP manufactured by Prime Polymer Co., Ltd., 40% by mass) mixed in a pellet state at a blending ratio of 40% by mass was used, and only a low crystalline polypropylene was used as the core component.
The nonwoven fabric was formed using a spunbond apparatus (Reicofil 4 manufactured by Reicofil). The raw material is melt-extruded from the sheath component resin and the core component resin at a resin temperature of 220 ° C. using separate single-screw extruders, and from a core-sheath composite nozzle (nozzle number: 7377 holes) of 0.6 mm per nozzle. The molten resin was spun at a rate of 5 g / min so that the ratio of sheath component: core component was 10:90.
The fiber obtained by spinning was laminated on a net surface that was moving at a line speed of 60 m / min at a temperature of 16 ° C. and a cabin pressure of 4000 Pa. The fiber bundle laminated on the net surface was embossed with an embossing roll heated to 70 ° C. at a linear pressure of 20 N / mm, and wound on a take-up roll.
The obtained elastic nonwoven fabric was subjected to the following measurements and evaluations. The results are shown in Table 2.

[Measurement and evaluation]
(1) Continuous formability Evaluation was performed by the number of times of winding around a calendar roll during molding for 1 hour.
A: There is no winding.
B: Winding is 1 to 2 times.
C: Winding is 3 times or more.

(2) Releaseability from take-up roll The nonwoven fabric taken up on the roll was left at room temperature for 2 weeks, and then peeled off from the roll. At that time, the case where it was fixed and could not be peeled off was determined as x, and the case where it was not fixed was determined as ◯.

(3) Measurement of elastic recovery rate From the obtained elastic nonwoven fabric, a test piece having a length of 200 mm and a width of 25 mm was sampled in the machine direction (MD) and the direction perpendicular to the machine direction (TD). Using a tensile tester (manufactured by Shimadzu Corporation, Autograph AG-I), the initial length L ₀ was set to 100 mm, and after 100% elongation at a tensile speed of 300 mm / min, it was immediately returned at 300 mm / min. The length L (mm) when the stress was 0 was measured. The elastic recovery rate (%) was calculated by the following formula.
Elastic recovery rate (%) = (2-L / L ₀ ) × 100

(4) Evaluation of stickiness of elastic nonwoven fabric The touch was evaluated by 10 panelists. The score is 2 points if you feel no stickiness, 1 point if you feel a little stickiness, 0 point if you feel stickiness, and the total score of 10 panelists is 14 points or higher A, 10-13 points B, 9 points or less were determined as evaluation C.

(5) Shrinkage at the time of HMA (hot melt adhesive) application Using a spray applicator manufactured by Nordson Co., Ltd., an SBS hot melt adhesive was applied from a nozzle with a diameter of 0.5 mm to a nozzle air pressure of 0.03 MPa, The elastic nonwoven fabric was coated at a coating temperature of 160 ° C., a coating amount of 0.6 g / m, and a line speed of 10 m / min. The appearance of the coated surface was observed to determine the presence or absence of surface roughness due to shrinkage.

Example 2
In Example 1, an elastic nonwoven fabric was molded in the same manner as in Example 1 except that the low crystalline polypropylene content of the sheath component was 90% by mass and the ratio of the sheath component: core component was 50:50. Measurement and evaluation were performed. The results are shown in Table 2.

Example 3
In Example 1, an elastic nonwoven fabric was molded in the same manner as in Example 1 except that the low crystalline polypropylene content of the sheath component was 80% by mass and the ratio of the sheath component: core component was 20:80. Measurement and evaluation were performed. The results are shown in Table 2.

Example 4
In Example 1, an elastic nonwoven fabric was molded in the same manner as in Example 1 except that the low crystalline polypropylene content of the sheath component was 90% by mass and the ratio of the sheath component: core component was 10:90. Measurement and evaluation were performed. The results are shown in Table 2.

Example 5
In Example 1, the elastic nonwoven fabric was molded in the same manner as in Example 1 except that the low crystalline polypropylene content of the sheath component was 40% by mass and the ratio of the sheath component: core component was 20:80. Measurement and evaluation were performed. The results are shown in Table 2.

Comparative Example 1
In Example 1, the elastic component was the same as in Example 1 except that the low crystalline polypropylene content of the sheath component was 95% by mass, the high crystalline polypropylene content was 5% by mass, and the core component was the same resin as the sheath component. The nonwoven fabric was shape | molded and the same measurement and evaluation were performed. The results are shown in Table 2.

Comparative Example 2
In Example 1, an elastic nonwoven fabric was molded in the same manner as in Example 1 except that both the sheath component and the core component were low crystalline polypropylene, and the same measurement and evaluation were performed. The results are shown in Table 2.

  The elastic nonwoven fabric of the present invention is suitably used for various textile products such as disposable diapers, sanitary products, sanitary products, clothing materials, bandages and packaging materials.

Claims (4)

An elastic nonwoven fabric comprising a core-sheath type composite fiber containing a low crystalline polypropylene satisfying the following (a) to (f).
(A) [mmmm] = 20-60 mol%
(B) [rrrr] / (1- [mmmm]) ≦ 0.1
(C) [rmrm]> 2.5 mol%
(D) [mm] × [rr] / [mr] ² ≦ 2.0
(E) Weight average molecular weight (Mw) = 10,000 to 200,000
(F) Molecular weight distribution (Mw / Mn) <4 The sheath component contains 50 to 99% by mass of low crystalline polypropylene and 1 to 50% by mass of highly crystalline polypropylene, and the core component is 90 to 100% by mass of low crystalline polypropylene and 0 to 10% by mass. The elastic nonwoven fabric according to claim 1, wherein the elastic non-woven fabric comprises a core-sheath type composite fiber containing high crystalline polypropylene and having a core component containing a low crystalline polypropylene having a higher content than the sheath component. 2. The elastic nonwoven fabric according to claim 1, comprising a core-sheath type composite fiber having a total low crystalline polypropylene content calculated by the following formula of 90% by mass or more and 99% by mass or less.
Total low crystalline polypropylene content = (Ws × Xs + Wc × Xc) / 100
Ws: Mass fraction of sheath component Wc: Mass fraction of core component Xs: Mass fraction of low crystalline polypropylene in sheath component Xc: Mass fraction of low crystalline polypropylene in core component The textiles using the elastic nonwoven fabric in any one of Claims 1-3.