CRIMPED FIBER AND NONWOVEN FABRIC

Abstract

Provided is a crimped fiber constituted of the following first component and second component, wherein the first component is a propylene-based resin composition containing a propylene-based polymer (1-A) in which a melting point (Tm-D) obtained under a specified condition exceeds 120 C. and a propylene-based polymer (1-B) satisfying the conditions that (a) a weight average molecular weight (Mw) is 10,000 to 200,000, (b) a molecular weight distribution (Mw/Mn) is less than 4.0, and (c) a melting point (Tm-D) obtained under a specified condition is 0 to 120 C.; and the second component is a propylene-based polymer (2) in which a melt flow rate (MFR) under the foregoing measurement condition is 1 g/10 min or more and 2,000 g/10 min or less, and a melting point (Tm-D) observed under the foregoing measurement condition by using a differential scanning calorimeter (DSC) exceeds 120 C., or a propylene-based resin composition containing the propylene-based polymer (2).

Claims

1. A crimped fiber, comprising a first component and a second component, wherein the first component is a propylene-based resin composition comprising a propylene-based polymer (1-A), which has a melt flow rate (MFR) measured at a temperature of 230 C. and a load of 21.18 N of 1 g/10 min or more and 2,000 g/10 min or less, and a melting point (Tm-D) measured as a peak top of a peak observed on the highest temperature side of a melting endothermic curve obtained by holding under a nitrogen atmosphere at 10 C. for 5 minutes and then increasing the temperature at a rate of 10 C./min by using a differential scanning calorimeter (DSC) of higher than 120 C., and a propylene-based polymer (1-B) satisfying the following conditions (a) to (c): (a) a weight average molecular weight (Mw) is 10,000 to 200,000, (b) a molecular weight distribution (Mw/Mn) is less than 4.0, and (c) a melting point (Tm-D) measured under the foregoing measurement condition is 0 to 80 C., and the second component is a propylene-based polymer (2), which has a melt flow rate (MFR) measured under the foregoing measurement condition of 1 g/10 min or more and 2,000 g/10 min or less, and a melting point (Tm-D) measured under the foregoing measurement condition of higher than 120 C., or a propylene-based resin composition comprising the propylene-based polymer (2).

2. The crimped fiber according to claim 1, wherein the melt flow rate (MFR) of the resin component in the first component and the melt flow rate (MFR) of the resin component in the second component are different.

3. The crimped fiber according to claim 1, wherein a degree of crystallization of the resin component in the first component and a degree of crystallization of the resin composition in the second component are different, wherein the degree of crystallization is determined with a differential scanning calorimeter.

4. The crimped fiber according to claim 1, wherein a half-crystallization time of the resin component in the first component and a half-crystallization time of the resin component in the second component are different, wherein the degree of crystallization is determined with a differential scanning calorimeter.

5. The crimped fiber according to claim 1, wherein the first component comprises the propylene-based polymer (1-B) in an amount of 1% by mass or more and 95% by mass or less, and a mass ratio of the propylene-based resin composition in the first component to the propylene-based resin composition in the second component is from 10/90 to 90/10.

6. The crimped fiber according to claim 1, wherein the propylene-based polymer (1-B) is a propylene homopolymer or a copolymer having a copolymerization ratio of a propylene unit of 50 mol % or more.

7. The crimped fiber according to claim 1, wherein the propylene-based polymer (1-B) is a propylene homopolymer.

8. The crimped fiber according to claim 1, wherein the crimped fiber is a side-by-side type fiber or an eccentric core-sheath type fiber.

9. A nonwoven fabric, comprising the crimped fiber according to claim 1.

10. A multilayered nonwoven fabric, comprising a laminate of two or more layers, wherein at least one layer thereof is the nonwoven fabric according to claim 9.

Description

EXAMPLES

Production Example

Preparation of Propylene-Based Polymer (1-B)[I], Propylene-Based Polymer (1-B)[II], and Propylene-Based Polymer (1-B)[III]

[0135] Into a stirrer-equipped stainless steel-made reactor having an internal volume of 0.25 m.sup.3, 26 L/h of n-heptane, 7.7 mmol/h of triisobutylaluminum, and further a catalyst component obtained by previously bringing dimethylanilinium tetrakis(pentafluorophenyl)borate, (1, 2-dimethylsilylene)(2,1-dimethylsilylene)-bis(3-trimethylsilylmethylindenyl)zirconium dichloride, triisobutylaluminum, and propylene into contact with each other while these were continuously supplied. Propylene and hydrogen were continuously supplied so as to keep a whole pressure within the reactor to 1.0 MPa.G, and a polymerization temperature was properly adjusted to obtain a polymerization solution having a desired molecular weight. To the resulting polymerization solution, an antioxidant was added in an amount of 1,000 ppm by mass, and the solvent was removed to obtain a propylene-based polymer (1-B)[I]r, a propylene-based polymer (1-B)[II], and a propylene-based polymer (1-B)[III], respectively.

[0136] Raw materials used in the Examples and Comparative Examples are shown below. [0137] [1] Y2005GP, manufactured by Prime Polymer Co., Ltd.

[0138] MFR: 20 g/10 min (measured at a temperature of 230 C. and a load of 21.18 N in conformity with JIS K7210:1999) [0139] [2] S119, manufactured by Prime Polymer Co., Ltd.

[0140] MFR: 60 g/10 min (measured at a temperature of 230 C. and a load of 21.18 N in conformity with JIS K7210:1999) [0141] [3] Moplen HP461Y, manufactured by PolyMirae

[0142] MFR: 1,300 g/10 min (measured at a temperature of 230 C. and a load of 21.18 N in conformity with ASTM D1238)

[0143] Physical properties of the above-described propylene-based polymers are shown in the following Table 1.

[0144] The above-described physical properties were determined according to the following measurements. [0145] [Measurement of Weight Average Molecular Weight (Mw) and Molecular Weight Distribution (Mw/Mn)]

[0146] The weight average molecular weight (Mw) and the molecular weight distribution (Mw/Mn) were determined by the gel permeation chromatography (GPC) method. The following device and conditions were used in the measurement to obtain a weight average molecular weight as converted into polystyrene. [0147] <GPC Measuring Device>

[0148] Column: TOSO GMHHR-H(S)HT, manufactured by Tosoh Corporation

[0149] Detector: RI detector for liquid chromatography (manufactured by Waters Corporation) [0150] <Measurement Conditions>

[0151] Solvent: 1,2,4-Trichlorobezene

[0152] Measurement temperature: 145 C.

[0153] Flow rate: 1.0 mL/min

[0154] Sample concentration: 2.2 mg/mL

[0155] Injection amount: 160 L

[0156] Calibration curve: Universal Calibration

[0157] Analysis program: HT-GPC (Ver. 1.0) [0158] [Measurement of .sup.13C-NMR Spectrum]

[0159] The .sup.13C-NMR spectrum was measured with the following device under the following conditions in accordance with the assignment of a peak, as proposed by A. Zambelli, et al., Macromolecules, 8, 687 (1975).

[0160] Device: .sup.13C-NMR device, JNM-EX400 Model, manufactured by JEOL, Ltd.

[0161] Method: Proton complete decoupling method

[0162] Concentration: 220 mg/mL

[0163] Solvent: Mixed solvent of 1,2,4-trichlorobenzene and deuterated benzene in a ratio of 90/10 (volume ratio)

[0164] Temperature: 130 C.

[0165] Pulse width: 45

[0166] Pulse repetition time: 4 seconds

[0167] Accumulation: 10,000 times [0168] <Calculating Expressions>

M=m/S100

R=/S100

S=P+P

[0169] S: Signal intensity of carbon atoms in side chain methyl of all the propylene units

[0170] P: 19.8 to 22.5 ppm

[0171] P: 18.0 to 17.5 ppm

[0172] P: 17.5 to 17.1 ppm

[0173] : Racemic pentad chain, 20.7 to 20.3 ppm

[0174] m: Mesopentad chain, 21.7 to 22.5 ppm [0175] [Melting Point (Tm-D)]

[0176] A melting endotherm obtained by holding 10 mg of a sample at 10 C. for 5 minutes under a nitrogen atmosphere and then increasing the temperature at a rate of 10 C./min by using a differential scanning calorimeter (DSC-7, manufactured PerkinElmer Inc.) was determined in terms of a melting endotherm (H-D) and a glass transition temperature (Tg). In addition, a melting point (Tm-D) was determined from a peak top of a peak observed on the highest temperature side of the resulting melting endothermic curve. [0177] [Semi-Crystallization Time]

[0178] The semi-crystallization time of the resin component constituting each of the first component and the second component was measured by the following method.

[0179] The semi-crystallization time is measured using FLASH DSC (manufactured by Mettler Toledo International Inc.) by the following method. [0180] (1) A sample is heated and melted at 230 C. for 2 minutes and then cooled to 25 C. at a rate of 2,000 C./sec, thereby measuring a change in calorific value with time in an isothermal crystallization process at 25 C. [0181] (2) When an integrated value of the calorific value from the start of isothermal crystallization until the completion of crystallization was defined as 100%, a time from the start of isothermal crystallization until the integrated value of the calorific value became 50% was defined as the semi-crystallization time. [0182] [Degree of Crystallization]

[0183] The degree of crystallization of the resin component constituting each of the first component and the second component was measured by the following method.

[0184] Using a differential scanning calorimeter (DSC-7, manufactured PerkinElmer Inc.), 10 mg of a sample was held at 220 C. for 5 minutes under a nitrogen atmosphere, and the temperature was then decreased to 40 C. at a rate of 10 C./min. A melting endotherm AH was determined from an area surrounded by a line portion containing a peak of a melting endothermic curve obtained by holding the resulting sample at 40 C. for 5 minutes and then increasing the temperature to 220 C. at a rate of 10 C./min and a line connecting a point on the low-temperature side free from a change of the amount of heat with a point on the high-temperature side free from a change of the amount of heat as a baseline, and the degree of crystallization (%) was calculated according to the following expression.

Degree of crystallization (%)=(H/Hm)100

[0185] In the expression, Hm represents a melting endotherm of a perfect crystal, and Hm of polypropylene is 209 J/g.

TABLE-US-00001 TABLE 1 MFR Tm- Polypropylene- Mw/ (g/ D [mmmm] rrrr/(1- based polymer Mw Mn min) ( C.) (%) mmmm) Y2005GP 2.42 10.sup.5 4.5 20 161 94 S119 1.58 10.sup.5 3.7 60 166 91 Moplen HP461Y 1.10 10.sup.4 3.2 1300 165 nd* nd* Propylene-based 1.20 10.sup.5 2 50 80 51 0.05 polymer (1-B)[I] Propylene-based 7.5 10.sup.4 2 350 80 49 0.05 polymer (1-B)[II] Propylene-based 4.5 10.sup.4 2 2,000 80 47 0.05 polymer (1-B)[III] *Not detected

[0186] Next, the Examples and Comparative Examples of a side-by-side type fiber using the above-described raw materials are described.

Example 1

[0187] (Preparation of First Component)

[0188] 80% by mass of Y2005GP (a trade name, manufactured by Prime Polymer Co., Ltd.) as the propylene-based polymer (1-A) and 20% by mass of the propylene polymer 1-B)[I] obtained in the Production Example as the propylene-based polymer (1-B) were compounded to prepare the propylene-based resin composition (1) that is the first component. [0189] (Preparation of Second Component)

[0190] Only S119 (a trade name, manufactured by Prime Polymer Co., Ltd.) was used as the propylene-based polymer (2) to provide the second component. [0191] (Production of Crimpable Side-by-Side Type Fiber)

[0192] A crimped fiber is hereunder explained by referring to a side-by-side type fiber as an example.

[0193] The formation of a side-by-side type fiber was performed using a conjugate fiber spinning machine, bi-component spinning apparatus having two extruders. The propylene-based resin composition (1) that is the first component, and either the propylene-based polymer (2) or the propylene-based resin composition (2) that is the second component, were each separately melt extruded with a single-screw extruder at a resin temperature of 230 C., and the molten resin was discharged and spun from a side-by-side composite nozzle having a nozzle diameter of 0.22 mm (number of holes: 24 holes) at a rate of 1.0 g/min per single hole in a mass ratio of the first component to the second component of 50/50.

[0194] A side-by-side type fiber obtained by spinning was allowed to pass through two cleaning rolls at room temperature and then wound up around a take-up roll at a rate of 3,000 m/min.

[0195] The resulting fiber was evaluated by measurement methods as described later. The results are shown in Table 2.

Examples 2 to 3 and Comparative Examples 1 to 2

[0196] Spun side-by-side type fibers were obtained according to the preparation and production method of Example 1, except for changing the first component and the second component to compositions shown in Table 2.

[0197] The MFR of the propylene-based resin composition (1) that is the first component in Table 2 was measured with respect to the propylene-based resin composition (1) obtained by mixing on the basis of the composition of the first component shown in Table 2 under conditions at a temperature 230 C. and a load of 21.18 N in conformity with JIS K7210:1999.

[0198] A semi-crystallization time and a degree of crystallization of the propylene-based resin composition (1) that is the first component in Table 2 were measured by the above-described measurement methods.

[Evaluation Method]

(Evaluation of Flexibility of Fiber)

[0199] About 10 cm of the resulting fiber was collected from the take-up roll and evaluated using a cantilever testing machine having a slope with an angle of inclination of 45 C. on one end of a pedestal. A fiber bundle was slid at intervals of 0.5 cm on the pedestal in the slope direction, and a moving distance at a moment at which the fiber bundle was bent, and one end thereof touched at the slope was measured. It is meant that as this value is small, the flexibility of the fiber.Math.nonwoven fabric product is high.

[0200] Here, as for the evaluation results of the flexibility shown in Table 2, the case of 3 cm or less was judged as acceptance.

(Crimping Degree)

[0201] About 10 cm of the resulting side-by-side type fiber was collected from the take-up roll, and one fiber was separated from the bundled yarn and measured for a number of crimps per 1 mm using a microscope. Ten samples were used for the measurement, and an average value thereof was defined as the crimping degree. It is meant that as the value of the crimping degree is high, the fiber is crimped, and a bulky fiber.Math.nonwoven fabric product is obtained.

(Stretching Rate)

[0202] 5 cm (LO) of a bundle of the resulting crimpable side-by-side type fiber was collected, the fiber was stretched in a state of fixing one end of the bundle until crimping of the fiber disappeared, so that the fiber was fully stretched, and a length (L) thereof was measured. A value of L/LO obtained by dividing L by LO was calculated as the stretching rate. It is meant that as this stretching rate is high, the fiber is crimped, and a bulky fiber.Math.nonwoven fabric product is obtained.

TABLE-US-00002 TABLE 2 Compar- Compar- ative ative Polypropylene-based polymer MFR Example 1 Example 2 Example 3 Example 1 Example 2 First (1-A) Y2005GP 20 g/10 min 80% by mass 60% by mass 80% by mass 100% by mass 0% by mass component S119 60 g/10 min 0% by mass 0% by mass 0% by mass 0% by mass 100% by mass (1-B) Propylene-based 50 g/10 min 20% by mass 40% by mass 20% by mass 0% by mass 0% by mass polymer (1-B)[I] Total MFR (g/10 min) 24 29 24 20 60 Semi-crystallization time 0.127 0.186 0.127 0.066 0.066 (sec at 25 C.) Degree of 39 30 39 49 49 crystallization (%) Second (2) S119 60 g/10 min 100% by mass 100% by mass 0% by mass 100% by mass 100% by mass component (2) Y2005GP 20 g/10 min 0% by mass 0% by mass 100% by mass 0% by mass 0% by mass Total MFR (g/10 min) 60 60 20 60 60 Semi-crystallization time 0.066 0.066 0.066 0.066 0.066 (sec at 25 C.) Degree of crystallization (%) 49 49 49 49 49 First component/second component Mass ratio 50/50 50/50 50/50 50/50 50/50 Flexibility (cantilever testing machine) (cm) 3.0 1.0 3.0 5.5 5.0 Crimping degree Number of 1.5 1.7 1.0 1.1 0.0 crimps per mm Stretching rate (Times) 3.7 3.5 2.3 1.8 1.0

[0203] As is noted from the results of Table 2, Comparative Examples 1 and 2 using only the propylene polymer (1-A) as the first component are low in terms of flexibility, crimping degree, and stretching rate, and Comparative Examples 1 and 2 not using the propylene-based polymer (1-B)[I] produced in the Production Example as the propylene polymer (1-B) that is the first component are low in terms of crimping degree and stretching rate.

[0204] On the other hand, it is noted that Examples 1 to 3 using the propylene-based resin composition (1-B)[I] containing the above-described propylene polymer (1-A) and propylene polymer (1-B) as the first component are excellent in flexibility, are high in crimping degree, and are conspicuously improved in terms of stretching rate.

Example 4

(Preparation of First Component)

[0205] 80% by mass of NOVATEC SA03 (a trade name, manufactured by Nippon Polypropylene Corporation) as the propylene-based polymer (1-A) and 20% by mass of the propylene-based polymer (1-B)[II] obtained in the Production Example as the propylene-based polymer (1-B) were compounded to prepare a propylene-based resin composition that is the first component.

(Preparation of Second Component)

[0206] Only NOVATEC SA03 (a trade name, manufactured by Nippon Polypropylene Corporation) was used as the propylene-based polymer (2) to prepare the second component.

[0207] A melting point Tm-D of NOVATEC SA03 (a trade name, manufactured by Nippon Polypropylene Corporation) was 167 C.

(Production of Crimpable Side-by-Side Type Nonwoven Fabric)

[0208] The resin composition that is the first component and the resin composition that is the second component were each separately melt extruded with a single-screw extruder at a resin temperature of 240 C., and the molten resin was discharged and spun from a side-by-side composite nozzle having a nozzle diameter of 0.6 mm (number of holes: 1,795 holes) at a rate of 0.35 g/min per single hole in a mass ratio of the first component to the second component of 50/50.

[0209] The fibers obtained by spinning were sucked using an ejector placed at 1,400 mm beneath the nozzle at an ejector pressure of 2.0 kgf/cm.sup.2 while cooling with air at a temperature of 12.5 C. and at a wind velocity of 0.8 m/sec and laminated on a net surface placed at 255 mm beneath the nozzle and moving at a line speed of 71 m/min.

[0210] The fiber bundle thus laminated on the net surface was embossed by an embossing roll heated at 50 C. at a line pressure of 40 N/mm and wound up by a take-up roll.

[0211] The resulting nonwoven fabric was subjected to the following measurement and evaluation. The results are shown in Table 3.

(Evaluation of Bulkiness)

[0212] Ten sheets of nonwoven fabric samples having a size of 5 cm5 cm were superimposed, 1.9 g of a metal plate was placed on the superimposed nonwoven fabric sample, and a thickness of the superimposed nonwoven fabric samples was measured. It is meant that as the numerical value of the thickness is high, the nonwoven fabric is high in bulkiness.

(Embossing Area Ratio)

[0213] The embossing area ratio refers to an occupation ratio of an embossed pattern per unit area.

TABLE-US-00003 TABLE 3 Polypropylene-based polymer MFR Example 4 First (1-A) NOVATEC SA03 30 g/10 min 80% by mass component (1-B) Propylene-based polymer (1-B)[II] 350 g/10 min 20% by mass Total MFR (g/10 mm) 49 Second (2) NOVATEC SA03 30 g/10 min 100% by mass component Total MFR (g/10 min) 30 First component/second component Mass ratio 50/50 Bulkiness (mm) 11.2 Fiber diameter (denier) 1.2 Embossing area ratio (%) 17.4

[0214] It is noted from the results of Example 4 of Table 3 that a fiber assembly that is bulky and has favorable texture is obtained.

Example 5

(Preparation of First Component)

[0215] 80% by mass of NOVATEC SA03 (a trade name, manufactured by Nippon Polypropylene Corporation) as the propylene-based polymer (1-A) and 20% by mass of the propylene-based polymer 1-B)[II] obtained in the Production Example as the propylene-based polymer (1-B) were compounded to prepare a propylene-based resin composition that is the first component.

(Preparation of Second Component)

[0216] Only NOVATEC SA03 (a trade name, manufactured by Nippon Polypropylene Corporation) was used as the propylene-based polymer (2) to provide the second component.

(Production of Crimpable Side-by-Side Type Nonwoven Fabric)

[0217] The resin composition that is the first component and the resin composition that is the second component were each separately melt extruded with a single-screw extruder at a resin temperature of 240 C., and the molten resin was discharged and spun from a side-by-side composite nozzle having a nozzle diameter of 0.6 mm (number of holes: 1,795 holes) at a rate of 0.5 g/min per single hole in a mass ratio of the first component to the second component of 50/50.

[0218] The fibers obtained by spinning were sucked using an ejector placed at 1,400 mm beneath the nozzle at an ejector pressure of 2.0 kgf/cm.sup.2 while cooling with air at a temperature of 12.5 C. and at a wind velocity of 0.6 m/sec and laminated on a net surface placed at 255 mm beneath the nozzle and moving at a line speed of 72 m/min.

[0219] The fiber bundle laminated on the net surface was embossed by an embossing roll (embossing area ratio: 17.4%, engraved shape: rhomb) heated at 50 C. at a line pressure of 40 N/mm, and a nonwoven fabric having a basis weight of 20 g/m.sup.2 was wound up by a take-up roll.

[0220] The resulting nonwoven fabric was subjected to the following measurement and evaluation. The results are shown in Table 4.

(Evaluation of Number of Crimps)

[0221] The number of crimps was measured using an automated crimp elastic modulus measuring device according to the measurement method of a number of crimps as prescribed in JIS L1015:2000. One fiber was extracted from a cotton-like sample before embossing in such a manner that a tension was not applied to the fiber, a length when an initial load of 0.18 mN/tex was applied to 25 mm of the sample was measured, and the number of crimps at that time was counted, thereby determining the number of crimps in a length of 25 mm. It is meant that as the number of crimps is large, the fiber.Math.nonwoven fabric product is high in crimping properties.

(Evaluation of Bulkiness and Embossing Area Ratio)

[0222] The bulkiness was measured and evaluated according to the evaluation of bulkiness and embossing area ratio described in Example 4 while also including the following Examples. The embossing area ratio is also shown.

Example 6

[0223] A nonwoven fabric was formed and evaluated in the same manner as in Example 5, except that the ejector pressure was changed to 1.0 kgf/cm.sup.2. The results are shown in Table 4.

Example 7

[0224] A nonwoven fabric was formed and evaluated in the same manner as in Example 5, except that the ratio of the first component to the second component regarding the resins to be discharged was changed to 70/30. The results are shown in Table 4.

Example 8

[0225] A nonwoven fabric was formed and evaluated in the same manner as in Example 5, except that the ratio of the first component to the second component regarding the resins to be discharged was changed to 30/70. The results are shown in Table 4.

Example 9

[0226] A nonwoven fabric was formed and evaluated in the same manner as in Example 5, except that, in the preparation of the first component, the propylene-based polymer (1-B)[III] obtained in the Production Example was used as the propylene-based polymer (1-B). The results are shown in Table 4.

Example 10

[0227] A nonwoven fabric was formed and evaluated in the same manner as in Example 5, except that, in the preparation of the first component, the propylene-based polymer 1-B)[III] obtained in the Production Example was used as the propylene-based polymer (1-B), and the ratio of the first component to the second component regarding the resins to be discharged was changed to 70/30. The results are shown in Table 4.

Example 11

[0228] A nonwoven fabric was formed and evaluated in the same manner as in Example 5, except that, in the preparation of the first component, 78% by mass of NOVATEC SA03 (a trade name, manufactured by Nippon Polypropylene Corporation), 20% by mass of the propylene-based polymer (1-B)[III] obtained in the Production Example as the propylene-based polymer (1-B), and 2% by mass of a slipping agent master batch (lubricant master batch) composed of 90% by mass of highly crystalline polypropylene (PP, Y6005GM, manufactured by Prime Polymer Co., Ltd.) and 10% by mass of erucic acid amide were compounded, and the ratio of the first component to the second component regarding the resins to be discharged was changed to 70/30. The results are shown in Table 4.

Example 15

[0229] A nonwoven fabric was formed and evaluated in the same manner as in Example 5, except that, in the preparation of the first component, 78% by mass of NOVATEC SA03 (a trade name, manufactured by Nippon Polypropylene Corporation), 20% by mass of the propylene-based polymer (1-B)[I] obtained in the Production Example as the propylene-based polymer (1-B), and 2% by mass of a slipping agent master batch (lubricant master batch) composed of 90% by mass of highly crystalline polypropylene (PP, Y6005GM, manufactured by Prime Polymer Co., Ltd.) and 10% by mass of erucic acid amide were compounded, and the ratio of the first component to the second component regarding the resins to be discharged was changed to 70/30. The results are shown in Tables 4 and 6.

TABLE-US-00004 TABLE 4 Propylene-based Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- polymer MFR ple 5 ple 6 ple 7 ple 8 ple 9 ple 10 ple 11 ple 15 First (1-A) NOVATEC SA03 30 g/10 min 80% 80% 80% 80% 80% 80% 78% 78% component by mass by mass by mass by mass by mass by mass by mass by mass (1-B) Propylene-based 50 g/10 min 0% 0% 0% 0% 0% 0% 0% 20% polymer (1-B)[I] by mass by mass by mass by mass by mass by mass by mass by mass Propylene-based 350 g/10 min 20% 20% 20% 20% 0% 0% 0% 0% polymer (1-B)[II] by mass by mass by mass by mass by mass by mass by mass by mass Propylene-based 2000 g/10 min 0% 0% 0% 0% 20% 20% 20% 0% polymer (1-B)[III] by mass by mass by mass by mass by mass by mass by mass by mass Slipping agent 60 g/10 min 0% 0% 0% 0% 0% 0% 2% 2% master batch by mass by mass by mass by mass by mass by mass by mass by mass Total MFR g/10 min 49 49 49 49 70 70 71 33 Second (2) NOVATEC SA03 30 g/10 min 100% 100% 100% 100% 100% 100% 100% 98% component by mass by mass by mass by mass by mass by mass by mass by mass Slipping agent 60 g/10 min 0% 0% 0% 0% 0% 0% 0% 2% master batch by mass by mass by mass by mass by mass by mass by mass by mass Total MFR g/10 min 30 30 30 30 30 30 30 30 First component/ Weight ratio 50/50 50/50 70/30 30/70 50/50 70/30 70/30 70/30 second component Content of propylene- % by mass 10 10 14 6 10 14 14 14 based polymer (1-B) relative to the whole of fiber Ejector pressure kgf/cm.sup.2 2.0 1.0 2.0 2.0 2.0 2.0 2.0 2.0 Embossing area ratio % 17.4 17.4 17.4 17.4 17.4 17.4 17.4 17.4 Bulkiness mm 5.4 5.1 6.8 4.9 5.4 5.4 4.8 7.8 Number of crimps Crimps/25 mm 13.8 10.7 15.7 8.8 13.9 17.0 18.3 11.7 Fiber diameter denier 1.3 2.0 1.2 1.3 1.4 1.2 1.2 1.2

[0230] It may be presumed that a difference in bulkiness between Example 4 shown in the foregoing Table 3 and Examples 5 to 11 shown in Table 4 is caused due to the degree of the crimping effect influenced by the yarn diameter.

[0231] In addition, it is noted from the results of Table 4 that by using the propylene-based polymer (1-B)[III] as the propylene polymer (1-B) that is the first component in place of the propylene-based polymer (1-B)[II] produced in the Production Example, the number of crimps of the resulting yarn becomes larger.

Example 12

(Preparation of First Component)

[0232] 66% by mass of PP3155 (a trade name, manufactured by ExxonMobil Chemical) as the propylene-based polymer (1-A), 4% by mass of a slipping agent master batch (lubricant master batch) composed of 95% by mass of highly crystalline polypropylene (PP, Y6005GM, manufactured by Prime Polymer Co., Ltd.) and 5% by mass of erucic acid amide, and 30% by mass of the propylene-based polymer (1-B)[II] obtained in the Production Example as the propylene-based polymer (1-B) were compounded to prepare a propylene-based resin composition that is the first component.

(Preparation of Second Component)

[0233] HG455FB (a trade name, manufactured by Borealis AG) as the propylene-based polymer (2) and 4% by mass of a slipping agent master batch (lubricant master batch) composed of 95% by mass of highly crystalline polypropylene (PP, Y6005GM, manufactured by Prime Polymer Co., Ltd.) and 5% by mass of erucic acid amide were compounded to prepare the second component.

(Production of Crimp able Side-by-Side Type Nonwoven Fabric)

[0234] The formation of a nonwoven fabric was performed using a spunbond machine (REICOFIL 4, manufactured by Reicofil GmbH). The resin compositions of the first component and the resin composition of the second component were spun in such a manner that the resin compositions were each separately melt extruded with a single-screw extruder at a resin temperature of 250 C. and discharged through a side-by-side type composite nozzle (number of holes: 1,795 holes) at a rate of 0.5 g/min per single hole in a mass ratio of the first component to the second component of 70/30.

[0235] The fibers obtained by spinning were laminated at a temperature of 20 C. and a cabin pressure of 3,000 Pa on a net surface moving at a line speed of 167 m/min. A fiber bundle thus laminated on the net surface was embossed with an embossing roll (pin-embossing/embossing area ratio: 12%, engraved shape: circle) heated at 131 C. at a line pressure of 50 N/mm, and a nonwoven fabric with a basis weight of 20 g/m.sup.2 was wound up around a take-up roll.

[0236] The resulting nonwoven fabric was measured and evaluated in the same manner as in Example 5. The results are shown in Table 5.

Example 13

[0237] A nonwoven fabric was formed and evaluated in the same manner as in Example 12, except that, in the preparation of the first component, 56% by mass of PP3155 (a trade name, manufactured by ExxonMobil Chemical), 4% by mass of a slipping agent master batch (lubricant master batch) composed of 95% by mass of highly crystalline polypropylene (PP, Y6005GM, manufactured by Prime Polymer Co., Ltd.) and 5% by mass of erucic acid amide, and 40% by mass of the propylene-based polymer (1-B)[II] obtained in the Production Example as the propylene-based polymer (1-B) were compounded to prepare a propylene-based resin composition that is the first component, and the temperature of the embossing roll was changed to 121 C. The results are shown in Table 5.

Example 14

[0238] A nonwoven fabric was formed and evaluated in the same manner as in Example 13, except that, in the preparation of the first component, the propylene-based polymer (1-B)[III] obtained in the Production Example was used as the propylene-based polymer (1-B), and the temperature of the embossing roll was changed to 115 C. The results are shown in Table 5.

[0239] The melting point Tm-D of HG455FB (a trade name, manufactured by Borealis AG) used herein as the second component (2) is 161 C. (in conformity with ISO 11357-3).

TABLE-US-00005 TABLE 5 Propylene-based polymer MFR Example 12 Example 13 Example 14 First (1-A) Exxon 3155 36 g/10 min 66% by mass 56% by mass 56% by mass component (1-B) Propylene-based polymer 350 g/10 min 30% by mass 40% by mass 0% by mass (1-B)[II] Propylene-based polymer 2000 g/10 min 0% by mass 0% by mass 40% by mass (1-B)[III] Slipping agent master batch 60 g/10 min 4% by mass 4% by mass 4% by mass Total MFR g/10 min 73 91 183 Second (2) HG455FB 27 g/10 min 96% by mass 96% by mass 96% by mass component Slipping agent master batch 60 g/10 min 4% by mass 4% by mass 4% by mass Total MFR g/10 min 28 28 28 First component/second component ratio Weight ratio 70/30 70/30 70/30 Content of propylene-based polymer (1-B) % by mass 21 28 28 relative to the whole of fiber Embossing temperature C. 131 121 115 Embossing area ratio % 12 12 12 Bulkiness mm 3.8 4.9 5.3 Number of crimps Crimps/25 mm 6.8 10.5 14.0 Fiber diameter denier 1.6 1.8 1.8

[0240] It is noted from the results of Table 5 that by using the propylene-based polymer 1-B)[III] as the propylene polymer (1-B) that is the first component in place of the propylene-based polymer 1-B)[II] produced in the Production Example, the number of crimps of the resulting yarn becomes larger.

[Uniformity of Formation]

[0241] Five sheets of specimens of 74 mm53 mm were prepared from the resulting nonwoven fabric. Subsequently, an image having been converted into digital data was obtained using a scanner in a state where a black drawing paper was superimposed on every specimen. Each of the resulting image data was processed to a gray scale (the degree of white and black was divided into 255 grades; it is meant that as the value is large, the color is white), thereby obtaining a histogram.

[0242] A peak of a librarian of the resulting histogram was compared with a value of the gray scale and evaluated in the following way.

[0243] A: Case where the initial peak of the histogram appears in 200 or more gray scales.

[0244] B: Case where the initial peak of the histogram appears in the range of 185 or more and less than 200 gray scales.

[0245] C: Case where the initial peak of the histogram appears in less than 185 gray scales.

Example 16

[0246] A nonwoven fabric was formed and evaluated in the same manner as in Example 5, except that in Example 5, in the preparation of the first component, 78% by mass of NOVATEC SA03 (a trade name, manufactured by Nippon Polypropylene Corporation), 20% by mass of the propylene-based polymer (1-B)[III] obtained in the Production Example as the propylene-based polymer (1-B), and 2% by mass of a slipping agent master batch (lubricant master batch) composed of 90% by mass of highly crystalline polypropylene (PP, Y6005GM, manufactured by Prime Polymer Co., Ltd.) and 10% by mass of erucic acid amide were compounded, and the ratio of the first component to the second component regarding the resins to be discharged was changed to 70/30. The results are shown in Table 6.

Example 17

[0247] A nonwoven fabric was formed and evaluated in the same manner as in Example 5, except that, in the preparation of the first component, 78% by mass of NOVATEC SA03 (a trade name, manufactured by Nippon Polypropylene Corporation), 10% by mass of the propylene-based polymer (1-B)[III] obtained in the Production Example and 10 parts by mass of Moplen HP461Y (a trade name, manufactured by PolyMirae) as the propylene-based polymer (1-B), and 2% by mass of a slipping agent master batch (lubricant master batch) composed of 90% by mass of highly crystalline polypropylene (PP, Y6005GM, manufactured by Prime Polymer Co., Ltd.) and 10% by mass of erucic acid amide were compounded, and the ratio of the first component to the second component regarding the resins to be discharged was changed to 70/30. The results are shown in Table 6.

Comparative Example 3

[0248] A nonwoven fabric was formed and evaluated in the same manner as in Example 5, except that, in the preparation of the first component, 78% by mass of NOVATEC SA03 (a trade name, manufactured by Nippon Polypropylene Corporation), 20 parts by mass of Moplen HP461Y (a trade name, manufactured by PolyMirae) as the propylene-based polymer (1-B), and 2% by mass of a slipping agent master batch (lubricant master batch) composed of 90% by mass of highly crystalline polypropylene (PP, Y6005GM, manufactured by Prime Polymer Co., Ltd.) and 10% by mass of erucic acid amide were compounded, and the ratio of the first component to the second component regarding the resins to be discharged was changed to 70/30. The results are shown in Table 6.

TABLE-US-00006 TABLE 6 Comparative Propylene-based polymer MFR Example 15 Example 16 Example 17 Example 3 First (1-A) NOVATEC SA03 30 g/10 min 78% by mass 78% by mass 78% by mass 78% by mass component (1-B) Propylene-based polymer (1-B)[I] 50 g/10 min 20% by mass 0% by mass 0% by mass 0% by mass Propylene-based polymer (1-B)[III] 2000 g/10 min 0% by mass 20% by mass 10% by mass 0% by mass Moplen HO461Y 1200 g/10 min 0% by mass 0% by mass 10% by mass 20% by mass Slipping agent master batch 60 g/10 min 2% by mass 2% by mass 2% by mass 2% by mass Total MFR g/10 min 71 71 66 64 Second (2) NOVATEC SA03 30 g/10 min 98% by mass 98% by mass 98% by mass 98% by mass component Slipping agent master batch 60 g/10 min 2% by mass 2% by mass 2% by mass 2% by mass Total MFR g/10 min 30 30 30 30 First component/second component ratio Weight ratio 70/30 70/30 70/30 70/30 Content of propylene-based polymer (1-B) % by mass 14 14 7 0 relative to the whole of fiber Ejector pressure kgf/cm.sup.2 2.0 2.0 2.0 2.0 Embossing area ratio % 17.4 17.4 17.4 17.4 Number of crimps Crimps/25 mm 11.7 20.0 24.2 Unmeasurable* Uniformity of formation* A A B C *Unmeasurable because of a frequent occurrence of roping just beneath the ejector

INDUSTRIAL APPLICABILITY

[0249] The crimped fiber of the present invention is a fiber having strong crimpability using a polyolefin-based material without performing a post-treatment, such as stretching, heating, etc., and is useful for producing a fiber assembly (for example, a nonwoven fabric) that is bulky and favorable in texture and a filter or a wiper using the same. In addition, the nonwoven fabric including the crimped fiber of the present invention is suitably used for various fiber products, for example, a disposable diaper, a sanitary product, a hygienic product, a clothing material, a bandage, a packaging material, etc.