SF-2532 1
f
DESCRIPTION
CRIMPED CONJUGATED FIBER AND NON-WOVEN FABRIC COMPRISING THE FIBER
5 TECHNICAL FIELD
[0001]
The present invention relates to crimped conjugated fibers
and a non-woven fabric comprising the fibers.
10 BACKGROUND ART
[0002]
Polypropylene non-woven fabrics have excellent properties
such as breathability and softness and are used as sanitary
materials including disposable diapers and sanitary napkins.
15 However, further improvements in their properties have been
required. For example, polypropylene non-woven fabrics further
improved in softness, bulkiness and mechanical strength are
desired.
[0003]
20 To obtain non-woven fabrics having excellent softness and
bulkiness, various methods have been proposed in which non-woven
fabrics are formed of crimped polypropylene fibers. For example.
Patent Document 1 discloses non-woven fabrics that comprise
conjugated fibers having a crimpable cross-sectional
SF-2532 2
configuration wherein the conjugated fibers comprise a first
component comprising propylene polymer and a second component
comprising polypropylene with different physical properties from
the first component. The second polypropylene is selected from
5 the group consisting of high MFR polypropylenes, low
polydispersity polypropylenes, amorphous polypropylenes and
elastic (elastomeric) polypropylenes. According to the
disclosure, by composite melt spinning the first component and
the second component having different physical properties from
10 each other, the resultant conjugated fibers give crimped fibers
capable of forming non-woven fabrics with excellent softness and
elastic properties.
[0004]
Patent Document 2 discloses non-woven fabrics that comprise
15 parallel type crimped conjugated fibers comprising
ethylene/propylene random copolymer and polypropylene.
[0005]
Patent Document 3 discloses non-woven fabrics that comprise
crimped conjugated fibers comprising two propylene polymers of
20 which a difference between the melting points is 20°C or more.
Patent Document 3 describes that the propylene polymers may be
blended with various known additives.
[0006]
In Patent Document 1, crimped conjugated fibers are obtained
SF-2532 3
from a combination of polypropylenes having dissimilar properties,
In detail. Example 1 discloses a combination of polypropylenes
having differing MFR and molecular weight distribution in which
parallel type conjugated fibers are formed from a first
5 polypropylene having an MFR of 35 and a polydispersity number of
3 and a second polypropylene having an MFR of 25 and a
polydispersity number of 2.
[0007]
The conjugated fibers obtained by combining
10 ethylene/propylene random copolymer and polypropylene that
differ in crystallization rate and the crimped conjugated fibers
obtained by combining two propylene polymers of which a difference
between the melting points is 20°C or more, as described in Patent
Document 2 and Patent Document 3, are excellent in crimp properties,
15 However, depending on applications, non-woven fabrics further
excellent in crimp properties and bulkiness are desired.
CITATION LIST
PATENT DOCUMENTS
20 [0008]
Patent Document 1: JP-A-2002-529617
Patent Document 2: JP-A-H07-197367
Patent Document 3: WO 2002/061192
SF-2532
SUMMARY OF THE INVENTION
TECHNICAL PROBLEM
[0009]
It is an object of the present invention to obtain conjugated
5 fibers having crimp properties and a non-woven fabric excellent
in softness, fuzzing resistance and visibility, obtained from the
fibers.
TECHNICAL SOLUTION
10 [0010]
The present inventors studied diligently and have found that
crimped fibers improved in softness and visibility while having
high crimp properties, for example conjugated fibers having an
eccentric core-sheath configuration, are obtained from two olefin
15 polymers differing in physical properties such as melting point
and MFR by adding a fatty acid amide having 19 or less carbon atoms
to an olefin polymer used in the sheath and/or an olefin polymer
used in the core. The present invention has been completed based
on the finding.
20 [0011]
In accordance with an aspect of the present invention, there
is provided a crimped conjugated fiber having a crimpable
cross-sectional configuration, wherein a cross section of the
fiber comprises at least two portions: a portion (a) and a portion
SF-2532 5
(b);
the mass ratio of the portion (a) to the portion (b)
[(a):{b)] is in the range of 10:90 to 60:40;
the portion (a) comprises an olefin polymer (A) and the
5 portion (b) comprises an olefin polymer (B);
the olefin polymer (A) differs from the olefin polymer (B)
in any one of Mz/Mw, melting point and MFR; and
a fatty acid amide having 19 or less carbon atoms is added
to the olefin polymer (A) and/or the olefin polymer (B).
10
ADV3^NTAGE0US EFFECT OF THE INVENTION
[0012]
The crimped conjugated fibers of the present invention are
capable of providing a non-woven fabric superior in bulkiness,
15 softness, fuzzing resistance and uniformity while having high
crimp properties compared with conventional crimped conjugated
fibers composed of an olefin polymer. Especially, a non-woven
fabric superior in visibility and uniformity is obtained by
combining olefin polymers composing the crimped conjugated fibers
20 wherein the difference between the melting points of the olefin
polymers is in the range of less than 20°C.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013]
SF-2532 6
Fig. 1 is a perspective view showing an embodiment of a
crimped conjugated fiber according to the present invention.
Fig. 2 is a cross-sectional view showing an embodiment of
a crimped conjugated fiber according to the present invention.
5 Fig. 3 is a cross-sectional view showing an embodiment of
a crimped conjugated fiber according to the present invention.
Fig. 4 is a cross-sectional view showing an embodiment of
a crimped conjugated fiber according to the present invention.
Fig. 5 is a cross-sectional view showing an embodiment of
10 a crimped conjugated fiber according to the present invention.
Fig. 6 is a cross-sectional view showing an embodiment of
a crimped conjugated fiber according to the present invention.
Fig. 7 is a cross-sectional view showing an embodiment of
a crimped conjugated fiber according to the present invention.
15
DESCRIPTION OF EMBODIMENTS
[0014]
<01efin polymer (A)>
In the crimped conjugated fibers of the present invention
20 having a crimpable cross-sectional configuration wherein a cross
section of the fibers comprises at least two portions: a portion
(a) and a portion (b) (hereinafter may be simply referred to as
"crimped conjugated fibers"), the olefin polymer (A) for forming
the portion (a) is a homo- or copolymer of an a-olefin such as
SF-2532 7
IT
ethylene, propylene, 1-butene, 1-hexene, 4-methyl-l-pentene or
1-octene. Specific examples of the olefin polymer (A) are
crystalline olefin polymers including: ethylene polymers such as
high-pressure low-density polyethylenes, linear low-density
5 polyethylenes (so-called LLDPEs: ethylene/a-olefin random
copolymers) and high density polyethylenes; propylene polymers
such as propylene homopolymers and propylene/a-olefin
copolymers; 1-butene polymers such as 1-butene homopolymers and
1-butene/a-olefin copolymers; and 4-methyl-l-pentene polymers
10 such as 4-methyl-l-pentene homopolymers and
4-methyl-l-pentene/a-olefin copolymers.
[0015]
The olefin polymer (A) according to the present invention
differs from the olefin polymer (B) for forming the portion (b)
15 in the crimped conjugated fibers (hereinafter may be simply
referred to as "crimped conjugated fibers") according to the
present invention in at least any one of Mz/Mw, melting point and
MFR.
[0016]
20 The olefin polymer (A) according to the present invention
is preferably a propylene polymer (Al) because of having high
productivity and high strength.
[0017]

SF-2532 8
The propylene polymer (Al) for forming the portion (a) in
the crimped conjugated fibers according to the present invention
preferably has a ratio (Mz/Mw) of Z-average molecular weight (Mz)
to weight average molecular weight (Mw) of 2.0 or more, preferably
5 in the range of 2.1 to 4.5. The propylene polymer (Al) , by having
(Mz/Mw) within the above range, can be a propylene polymer having
a ratio [Mz/Mw (Al)] of Z-average molecular weight (Mz) to weight
average molecular weight (Mw) different from the ratio [Mz/Mw (B) ]
of Z-average molecular weight (Mz) to weight average molecular
10 weight (Mw) of a propylene polymer (Bl) described later.
[0018]
The propylene polymer (Al) according to the present
invention usually has a melting point of not lower than 120°C,
preferably in the range of 125 to 165°C.
15 [0019]
When a propylene homopolymer (A2) or a propylene/a-olefin
copolymer (A3) having a melting point of 155°C or more, more
preferably in the range of 157 to 165°C, is used as the propylene
polymer (Al) according to the present invention, it is easy to
20 control the difference of the melting point between the propylene
polymer (Bl) described later and the propylene polymer (Al) to
be 5°C or more, more preferably 10°C or more.
[0020]
The propylene polymer (Al) according to the present
SF-2532 9
invention usually has a melt flow rate (MFR) (ASTM D-1238, 230°C,
2160 g load) of 20 to 100 g/10 min, preferably 30 to 80 g/10 min.
If MFR of the propylene polymer is less than 20 g/10 min, the melt
viscosity is high and the spinnability is poor. If MFR of the
5 propylene polymer exceeds 100 g/10 min, an obtainable non-woven
fabric may have poor tensile strength.
[0021]
The propylene polymer (Al) according to the present
invention is a propylene polymer containing propylene as a main
10 component, with examples including a propylene homopolymer and
a propylene/a-olefin random copolymer having a small amount, e.g.,
not more than 10 mol%,of one or more kind(s) of a-olefins such
as ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene,
3-methyl-l-butene, 3-methyl-l-pentene, 3-ethyl-l-pentene,
15 4-methyl-l-pentene and 4-methyl-l-hexene. Examples of the
propylene/a-olefin random copolymers include a
propylene/ethylene random copolymer and a
propylene/ethylene/1-butene random copolymer. The propylene
polymer (Al) is preferably a propylene homopolymer.
20 [0022]
The propylene polymer (Al) according to the present
invention is obtained by homopolymerizing propylene or
copolymerizing propylene and a small amount of a-olef in by a method
of slurry polymerization, gas-phase polymerization or bulk
SF-2532 10
polymerization using a Ziegler-Natta catalyst that contains a
titanium-containing solid transition metal component and an
organometallic component or a metallocene catalyst that contains
a compound of transition metal of Groups IV to VI of the periodic
5 table having at least one cyclopentadienyl skeleton and a
cocatalyst component.
[0023]
The propylene polymer (Al) according to the present
invention may be blended with known additives or other polymers
10 as required while still achieving the objects of the present
invention, as well as a fatty acid amide having 19 or less carbon
atoms. Exemplary additives are antioxidants, weathering
stabilizers, light stabilizers, antistatic agents, anti-fogging
agents, anti-blocking agents, lubricants, nucleating agents and
15 pigments.
[0024]
<01efin polymer (B)>
In the crimped conjugated fibers of the present invention
having a crimpable cross-sectional configuration wherein a cross
20 section of the fibers comprises at least two portions: a portion
(a) and a portion (b), the olefin polymer (B) for forming the
portion (b) is a crystalline olefin polymer of which the category
is the same as that of the olefin polymer (A) . The olefin polymer
(B) differs from the olefin polymer (A) in at least any one of
SF-2532 11
Mz/Mw, melting point and MFR.
[0025]
The olefin polymer (B) according to the present invention
is preferably a propylene polymer (Bl) because of having high
5 productivity and high strength.

The propylene polymer (Bl) for forming the portion (b) in
the crimped conjugated fibers according to the present invention
preferably has a ratio (Mz/Mw) of Z-average molecular weight (Mz)
10 to weight average molecular weight (Mw) of 2.0 or more, preferably
in the range of 2.1 to 4.5. The propylene polymer (Bl) , by having
(Mz/Mw) within the above range, can be a propylene polymer having
a ratio [Mz/Mw (Bl) ] of Z-average molecular weight (Mz) to weight
average molecular weight (Mw) different from the ratio [Mz/Mw
15 (Al)] of Z-average molecular weight (Mz) to weight average
molecular weight (Mw) of the propylene polymer (Al).
[0026]
The propylene polymer (Bl) according to the present
invention usually has a melting point of not lower than 120°C,
20 preferably in the range of 125 to 165°C.
[0027]
When a propylene/a-olefin copolymer (B2) preferably having
a melting point of 120 to 155°C, more preferably in the range of
125 to 150°C, is used as the propylene polymer (Bl) according to
SF-2532 12
the present invention, it is easy to control the difference of
the melting point between the propylene polymer (Bl) and the
propylene polymer (Al) or the propylene homopolymer (A2) to be
5°C or more, more preferably 10°C or more.
5 [0028]
The propylene polymer (Bl) according to the present
invention usually has a melt flow rate (MFR) (ASTM D-1238, 230°C,
2160 g load) of 20 to 100 g/10 min, preferably 30 to 80 g/10 min.
If MFR of the propylene polymer is less than 20 g/10 min, the melt
10 viscosity is high and the spinnability is poor. If MFR of the
propylene polymer exceeds 100 g/10 min, an obtainable non-woven
fabric may have poor tensile strength.
[0029]
The propylene polymer (Bl) according to the present
15 invention is a propylene homopolymer or a random copolymer of
propylene with a small amount, e.g., not more than 10 mol% of an
a-olefin, specifically, one or more a-olefins (excluding
propylene) such as ethylene, 1-butene, 1-pentene, 1-hexene,
1-octene, 1-decene, 3-methyl-l-butene, 3-methyl-l-pentene,
20 3-ethyl-l-pentene, 4-methyl-l-pentene and 4-methyl-l-hexene.
[0030]
The propylene polymer (Bl) according to the present
invention can be produced by the same polymerization method as
in the case of the propylene polymer (Al).
SF-2532 13
[0031]
The propylene polymer (Bl) according to the present
invention may be blended with known additives or other polymers
as required while still achieving the objects of the present
5 invention, as well as a fatty acid amide having 19 or less carbon
atoms. Exemplary additives are antioxidants, weathering
stabilizers, light stabilizers, antistatic agents, anti-fogging
agents, anti-blocking agents, lubricants, nucleating agents and
pigments.
10 [0032]

The fatty acid amide blended into the olefin polymer (A)
and/or the olefin polymer (B) according to the present invention
is a fatty acid amide having 19 or less, preferably 16 to 18, carbon
15 atoms. The number of carbon atoms in such a case refers to the
number of carbon atoms in a fatty acid moiety in a fatty acid amide.
The fatty acid that constitutes the fatty acid amide may be a
saturated fatty acid or an unsaturated fatty acid or may be a
primary amide or a secondary amide. Specific examples of the
20 fatty acid amide according to the present invention include
primary amides such as palmitic acid (C16) amide, stearic acid
(C18) amide and oleic acid (CIS) amide and secondary amides such
as N-oleylpalmitic acid {C16) amide, myristic acid amide (C13)
and lauric acid amide (Cll).
SF-2532 14
[0033]
Of the fatty acid amides, stearic acid (C18) amide, oleic
acid (C18) amide and N-oleylpalmitic acid (C16) amide are
particularly preferred in terms of softness, fuzzing resistance
5 and uniformity.
[0034]
If a fatty acid amide having more than 19 carbon atoms, e.g.,
erucic acid (C22) amide, is used as the fatty acid amide and added
to the propylene polymer, improved effects such as crimp
10 properties, softness, fuzzing resistance and uniformity are
insufficient.
[0035]

The crimped conjugated fibers of the present invention have
15 a crimpable cross-sectional configuration, wherein a cross
section of the fiber comprises at least two portions: a portion
(a) and a portion (b) ;
the mass ratio of the portion (a) to the portion (b)
[(a):(b)] is in the range of 10:90 to 60:40;
20 the portion (a) comprises an olefin polymer (A) and the
portion (b) comprises an olefin polymer (B);
the olefin polymer (A) differs from the olefin polymer (B)
in at least any one of Mz/Mw, melting point and MFR; and
a fatty acid amide having 19 or less carbon atoms is added
SF-2532 15
to the olefin polymer (A) and/or the olefin polymer (B).
[0036]
A combination of the olefin polymer (A) and the olefin
polymer (B) differing in Mz/Mw from each other is such that the
5 difference between the ratio [Mz/Mw (A)] of Z-average molecular
weight (Mz) to weight average molecular weight (Mw) of the olefin
polymer (A) and the ratio [Mz/Mw (B) ] of Z-average molecular weight
(Mz) to weight average molecular weight (Mw) of the olefin polymer
(B) is preferably in the range of 0.1 to 2.2, more preferably 0.1
10 to 0.4.
[0037]
Herein, Mz of the olefin polymer (A) or the olefin polymer
(B) is known as Z-average molecular weight and is defined by
Equation (1) below:
15 [0038]
Mz= ^"^'N,
(1)
Z Mi Ni
[0039]
In Equation (1) , Mi is the molecular weight of the polymer
(the olefin polymer (A) and the olefin polymer (B) ; hereinafter,
20 referred to as the "olefin polymer" when these two polymers are
combined) and Ni is the number of moles of the polymer (olefin
polymer).
[0040]
SF-2532 16
In general, Mz is considered to reflect more precisely
high-molecular weight components in a polymer. Therefore, the
Mz/Mw indicates a molecular weight distribution reflecting more
precisely high-molecular weight components than the usual
5 molecular weight distribution Mw/Mn. The molecular weight
distribution Mz/Mw affects fiber crimp properties.
[0041]

As long as Mz/Mw of the olefin polymer (A) is different from
10 Mz/Mw of the olefin polymer (B), an absolute value of the
difference between Mw/Mn(A) of the olefin polymer (A) according
to the present invention and Mw/Mn(B) of the olefin polymer (B)
[Mw/Mn (A) - Mw/Mn (B) : AMw/Mn] may be 1.5 or below, in which case
obtainable conjugated fibers still have excellent crimp
15 properties. Even when an absolute value of AMw/Mn is in the range
of 0.3 to 1.0, crimps are developed. The ratio Mw/Mn is usually
known as the molecular weight distribution (polydispersity
degree) indicating the degree of molecular weight distribution
of a polymer. If AMw/Mn is excessively large, flow properties
20 and crystallization behaviors greatly differ between one material
(the portion (a)) and another material (the portion (b) ) , possibly
resulting in deteriorated fiber spinnability. In the present
invention, the numerical ranges indicated with "to" include the
numbers at the sides of the "to".
SF-2532 l^
[0042]
Mz/Mw and AMw/Mn are obtained by determining, by GPC
analysis, the ratios Mz/Mw and the ratios Mw/Mn each for the olefin
polymer (A) and the olefin polymer (B) that form the portion (a)
5 and the portion (b) respectively, and calculating an absolute
value of the difference thereof,
[0043]
In the present invention, GPC analysis is performed under
the following conditions.
10 (1) 30 mg of the olefin polymer is completely dissolved in
20 mL of o-dichlorobenzene at 145°C.
(2) The solution is filtered through a sintered filter
having a pore size of 1.0 pm to provide a sample.
(3) The sample is analyzed by GPC and the average molecular
15 weight and molecular weight distribution curve are obtained with
reference to polystyrene (PS) standard.
[0044]
The measurement apparatus and conditions are as follows.
Measurement apparatus: Gel permeation chromatograph
20 Alliance GPC 2000 (manufactured by Waters)
Analyzer: Data processing software Empower 2 (manufactured
by Waters)
Columns: Two TSK gel GMH6-HT columns + two TSK gel GMH6-HTL
columns (each 7.5 mm in inner diameter x 30 cm, manufactured by
SF-2532 18
c
TOSOH CORPORATION)
Column temperature: 140°C
Mobile phase: o-dichlorobenzene (containing 0.025% of
butylated hydroxytoluene (BHT))
5 Detector: Differential refractometer
Flow rate: 1 mL/min
Sample concentration: 30 mg/20 mL
Injection amount: 500 |a.L
Sampling time intervals: 1 sec
10 Column calibration: Monodisperse polystyrenes
(manufactured by TOSOH CORPORATION)
Molecular weight conversion: PS conversion/standard
conversion methods
[0045]
15 The crimped conjugated fibers having excellent crimp
properties can be obtained by selecting the olefin polymer (A)
and the olefin polymer (B) differing in Mz/Mw, preferably having
the Mz/Mw difference within the above range, even if there is no
difference between the melting points or MFRs of the olefin polymer
20 (A) and the olefin polymer (B).
[0046]
As a combination of the olefin polymer (A) and the olefin
polymer (B) differing in Mz/Mw, a combination of the propylene
polymer (Al) and the propylene polymer (Bl) is preferred because
SF-2532 19
of high productivity and high strength.
[0047]
As a combination of the olefin polymer (A) and the olefin
polymer (B) differing in melting point from each other, preferred
5 is a combination of the olefin polymer (A) and the olefin polymer
(B) wherein the difference between their melting points is
preferably 5°C or more, more preferably more than 10°C, since the
crimped conjugated fibers superior in crimp properties are
provided. On the other hand, when the difference between the
10 melting points of the olefin polymer (A) and the olefin polymer
(B) exceeds 20°C, crimp properties are further improved, but a
non-woven fabric resulting from such crimped conjugated fibers
may have deteriorated visibility and uniformity, and therefore
the difference between the melting points of the olefin polymer
15 (A) and the olefin polymer (B) is more preferably less than 20°C.
[0048]
The difference between the melting points of the olefin
polymer (A) and the olefin polymer (B) is obtained by determining
the melting points of the olefin polymer (A) and the olefin polymer
20 (B) that are raw materials for the portion (a) and the portion
(b) respectively and calculating an absolute value of the
difference thereof.
[0049]
In the present invention, the melting point is measured as
SF-2532 20
follows.
[0050]
(1) The olefin polymer is set in a pan of a differential
scanning calorimeter (DSC) manufactured by PerkinElmer, Inc. The
5 pan is heated from 30 to 200°C at a rate of 10°C/min, held at 200°C
for 10 minutes, and cooled to 30°C at a rate of 10°C/min.
(2) The pan is heated again from 30 to 200°C at a rate of
10°C /min, and the melting point is obtained from the peak recorded
during this second heating process.
10 [0051]
The crimped conjugated fibers having excellent crimp
properties can be obtained by making the difference between the
melting points of the olefin polymer (A) and the olefin polymer
(B) within the above range, even if there is no AMz/Mw or MFR
15 difference of the olefin polymer (A) and the olefin polymer (B) .
[0052]
As a combination of the olefin polymer (A) and the olefin
polymer (B) differing in melting point, a combination of the
propylene homopolymer (A2) and the propylene/a-olefin copolymer
20 (B2) is preferred because of high productivity and high strength.
[0053]
The olefin polymer (A) and the olefin polymer (B) differing
in MFR are combined so that the difference between the MFRs of
the olefin polymer (A) and the olefin polymer (B) is preferably
SF-2532 21
5 or less, more preferably 3 or less.
[0054]
The crimped conjugated fibers having excellent crimp
properties can be obtained by making the difference between the
5 MFRs of the olefin polymer (A) and the olefin polymer (B) within
the above range, even if there is no AMz/Mw or melting point
difference of the olefin polymer (A) and the olefin polymer (B) .
[0055]
The combination of the olefin polymer (A) and the olefin
10 polymer (B) according to the present invention may be a combination
of the olefin polymers differing in all of Mz/Mw, melting point
and MFR.
[0056]
The amount of the blended fatty acid amide is usually in
15 the range of 0.1 to 10 parts by weight, preferably 0.1 to 3.0 parts
by weight, more preferably 0.1 to 2.0 parts by weight, based on
100 parts by weight of the olefin polymer (A) and/or the olefin
polymer (B) . If the amount of the blended fatty acid amide is
less than 0.1 part by weight, the crimp properties of the
20 obtainable crimped conjugated fibers are insufficient. On the
other hand, if the amount of the blended fatty acid amide exceeds
10 parts by weight, the effect of improving the crimp properties
is saturated and the amounts of the fatty acid amide spread on
the surfaces of the obtainable crimped conjugated fibers and a
SF-2532 22
non-woven fabric containing the fibers is increased, so that
molding processability may be deteriorated.
[0057]
In an embodiment, in the crimped conjugated fibers of the
5 present invention, the crimpable cross-sectional configuration
may be an eccentric core-sheath configuration in which the core
is the portion (a) formed of the olefin polymer (A) and the sheath
is the portion (b) formed of the olefin polymer (B). The core
formed of the portion (a) may be completely covered with the sheath
10 of the olefin polymer (B) , or part of the core may be exposed on
the surface of the crimped conjugated fibers. The joint between
the core and the sheath may be straight or curved. In an embodiment,
the joint between the core and the sheath may be straight and part
of the core may be exposed on the surface of the crimped conjugated
15 fibers, a configuration known as a side-by-side configuration.
[0058]

In the crimped conjugated fibers of the present invention,
the mass ratio of the portion (a) to the portion (b) [(a):(b)]
20 is in the range of 10:90 to 60:40, preferably 10:90 to 50:50, more
preferably 20:80 to 40:60. If the mass ratio of the portion (a)
to the portion (b) is in excess of or below the above range, the
significant effect of improving crimp properties is not obtained
even when the fatty acid amide is added.
SF-2532 23

The number of crimps of the crimped conjugated fibers of
the present invention is determined in accordance with JIS L 1015.
The number of crimps is usually 18 or more, preferably 20 to 50,
5 per 25 mm of the fiber, and further preferably 20 to 40, most
preferably 20 to 30, from the viewpoint of the visibility and
uniformity of an obtainable non-woven fabric. If the number of
crimps is less than the lower limit, the crimped fibers may not
achieve characteristics such as bulkiness by the three dimensional
10 helical structure. If the number of crimps is larger than the
upper limit, uniform distribution of the fibers is difficult and
an obtainable non-woven fabric may have deteriorated uniformity
or mechanical strength.
[0059]
15 The diameter of the crimped conjugated fibers of the present
invention is not particularly limited, but is usually in the range
of 0.5 to 5 denier, preferably 0.5 to 3 denier. This fineness
ensures excellent spinnability and crimp properties, and
mechanical strength of an obtainable non-woven fabric comprising
20 the crimped conjugated fibers of the present invention.
[0060]
Fig. 1 is a perspective view showing an embodiment of the
crimped conjugated fibers according to the present invention. In
the figure, reference numeral 10 denotes the portion (a) and
SF-2532 24
reference numeral 20 denotes the portion (b).
[0061]
The crimped conjugated fibers of the present invention have
a crimpable cross-sectional configuration wherein a cross section
5 of the fibers comprises at least two portions: the portion (a)
and the portion (b). In the cross section of the crimped
conjugated fibers, the proportions of the portion (a) and the
portion (b) are such that the mass ratio [ (a) : (b) ] is in the range
of 10:90 to 60:40, preferably 10 : 90 to 50 : 50, more preferably 20 : 80
10 to 40:60.
[0062]
The crimped conjugated fibers may have any shapes without
limitation as long as they have a crimpable cross-sectional
configuration. Exemplary shapes include side-by-side (parallel)
15 crimped conjugated fibers in which the portion (a) and the portion
(b) are arranged adjacent to each other, and core-sheath crimped
conjugated fibers in which the portion (a) forms a core (a') and
the portion (b) forms a sheath (b')-
[0063]
20 Figs. 2 to 7 show other cross-sectional views of crimped
conjugated fibers according to the present invention. In the
figures, reference numeral 10 denotes the portion (a) and
reference numeral 20 denotes the portion (b).
[0064]
SF-2532 25
9
The term "core-sheath crimped conjugated fibers" refers to
fibers which have a core and a sheath and are crimped. The core
(a') is arranged with at least part thereof being surrounded by
a polymer different from the core (a') in the fiber cross section
5 and extends along the length of the fiber. The sheath (b') is
arranged so as to surround at least part of the core (a') in the
fiber cross section and extends along the length of the fiber.
In an eccentric core-sheath crimped conjugated fiber, the core
(a') and the sheath (b') are located non-concentrically in the
10 cross section of the fiber. The eccentric core-sheath crimped
conjugated fibers include an exposed type in which the side of
the core (a') is exposed, and a non-exposed type in which the core
(a') is fully occluded. In the present invention, eccentric
core-sheath crimped conjugated fibers of the exposed type are
15 preferred because the eccentric core-sheath crimped conjugated
fibers of the exposed type can exhibit excellent crimp properties.
The cross sectional joint between the core (a') and the sheath
(b') may be straight or curved. The core may be circular,
elliptical or square in cross section.
20 [0065]
The crimped conjugated fibers of the present invention may
be staple fibers or continuous fibers. Continuous fibers are
preferable because an obtainable non-woven fabric does not have
loss of the crimped conjugated fibers and excellent fuzzing
SF-2532 26
resistance is achieved.
[0066]

The non-woven fabric of the present invention comprises the
5 above crimped conjugated fibers. The non-woven fabric usually
has a basis weight (mass per unit area of the non-woven fabric)
of 3 to 100 g/m^ preferably 7 to 60 g/m^.
[0067]
The non-woven fabric of the present invention preferably
10 comprises the crimped conjugated fibers that are continuous fibers.
In view of productivity, the non-woven fabric is particularly
preferably spunbonded non-woven fabric of such fibers.
[0068]
In the non-woven fabric of the present invention, it is
15 preferable that the crimped conjugated fibers are thermally fusion
bonded by embossing, whereby the fibers maintain stability and
strength.
[0069]
Further, the non-woven fabric of the present invention
20 comprises the crimped conjugated fibers, preferably crimped
conjugated continuous fibers, preferably having a KOSHI value of
7.4 or less and a uniformity index (V) of 420 or less, further
preferably a KOSHI value of 7.35 or less and a uniformity index
(V) of 400 or less, more preferably a KOSHI value of 7,3 or less
SF-2532 27
and a uniformity index (V) of 380 or less.
[0070]
The non-woven fabric having KOSHI and a uniformity index
(V) satisfying the above ranges is preferred because of being
5 excellent in softness and visibility.
[0071]

The non-woven fabric comprising the crimped conjugated
fibers of the present invention (hereinafter, also referred to
10 as the "crimped conjugated fiber non-woven fabric" to be
distinguished from a usual non-woven fabric) may be laminated with
various layers depending on use.
[0072]
In detail, the crimped conjugated fiber non-woven fabric
15 may be laminated with knitted fabrics, woven fabrics, non-woven
fabrics, films and the like. The crimped conjugated fiber
non-woven fabric may be laminated (joined) with such other layers
by known methods including thermal fusion bonding methods such
as heat embossing and ultrasonic fusion bonding, mechanical
20 entanglement methods such as needle punching and water jetting,
adhesive bonding methods with hot melt adhesives or urethane
adhesives, and extrusion laminating methods.
[0073]
The non-woven fabrics laminated with the crimped conjugated
SF-2532 28
fiber non-woven fabric include various known non-woven fabrics
such as spunbonded non-woven fabrics, meltblown non-woven fabrics,
wet non-woven fabrics, dry non-woven fabrics, dry pulp non-woven
fabrics, flash-spun non-woven fabrics and spread-fiber non-woven
5 fabrics.
[0074]
The materials for such non-woven fabrics may be conventional
thermoplastic resins. Examples thereof include homopolymers and
copolymers of a-olefins such as ethylene, propylene, 1-butene,
10 1-hexene, 4-methyl-l-pentene and 1-octene, namely, polyolefins
such as high-pressure low-density polyethylenes, linear
low-density polyethylenes (LLDPE), high-density polyethylenes,
polypropylenes, polypropylene random copolymers, poly-1-butene,
poly-4-methyl-l-pentene, ethylene/propylene random copolymers,
15 ethylene/1-butene random copolymers and propylene/1-butene
random copolymers; polyesters such as polyethylene terephthalate,
polybutylene terephthalate and polyethylene naphthalate;
polyamides such as nylon-6, nylon-66 and
polymethaxyleneadipamide; polyvinyl chloride, polyimides,
20 ethylene/vinyl acetate copolymers, polyacrylonitriles,
polycarbonates, polystyrenes, ionomers and thermoplastic
polyurethanes; and mixtures of these resins. Of these,
high-pressure low-density polyethylenes, linear low-density
polyethylenes (LLDPE), high-density polyethylenes.
SF-2532 29
polypropylenes, polypropylene random copolymers, polyethylene
terephthalate and polyamides are preferred.
[0075]
In a preferred embodiment of the present invention, the
5 crimped conjugated fiber non-woven fabric is laminated with a
spunbonded non-woven fabric made of an ultrafine fiber (fineness:
0.8 to 2.5 denier, more preferably 0.8 to 1.5 denier) and/or a
meltblown non-woven fabric. Specific examples include:
two-layer laminates such as spunbonded non-woven fabric
10 (ultrafine fiber) /crimped conjugated fiber non-woven fabric, and
meltblown non-woven fabric/crimped conjugated fiber non-woven
fabric; three-layer laminates such as spunbonded non-woven fabric
(ultrafine fiber)/crimped conjugated fiber non-woven
fabric/spunbonded non-woven fabric (ultrafine fiber) , spunbonded
15 non-woven fabric (ultrafine fiber)/crimped conjugated fiber
non-woven fabric/meltblown non-woven fabric, spunbonded
non-woven fabric (ultrafine fiber)/meltblown non-woven
fabric/crimped conjugated fiber non-woven fabric, crimped
conjugated fiber non-woven fabric/spunbonded non-woven fabric
20 (ultrafine fiber)/crimped conjugated fiber non-woven fabric,
crimped conjugated fiber non-woven fabric/spunbonded non-woven
fabric (ultrafine fiber) /meltblown non-woven fabric, and crimped
conjugated fiber non-woven fabric/meltblown non-woven
fabric/crimped conjugated fiber non-woven fabric; and laminates
SF-2532 30
having four or more layers such as spunbonded non-woven fabric
(ultrafine fiber)/crimped conjugated fiber non-woven
fabric/meltblown non-woven fabric/spunbonded non-woven fabric
(ultrafine fiber), spunbonded non-woven fabric (ultrafine
5 fiber)/crimped conjugated fiber non-woven fabric/meltblown
non-woven fabric/crimped conjugated fiber non-woven
fabric/spunbonded non-woven fabric (ultrafine fiber), crimped
conjugated fiber non-woven fabric/spunbonded non-woven fabric
(ultrafine fiber) /meltblown non-woven fabric/crimped conjugated
10 fiber non-woven fabric, and crimped conjugated fiber non-woven
fabric/spunbonded non-woven fabric (ultrafine fiber)/meltblown
non-woven fabric/spunbonded non-woven fabric (ultrafine
fiber)/crimped conjugated fiber non-woven fabric. The basis
weight of each non-woven fabric layer in the laminate is preferably
15 in the range of 2 to 25 g/m^. The spunbonded non-woven fabric made
of the ultrafine fibers described above may be obtained by
controlling (selecting) spunbonding conditions. The non-woven
fabric laminates benefit from the bulkiness and softness of the
crimped conjugated fiber non-woven fabric of the present invention
20 and also achieve excellent surface smoothness and improved water
resistance.
[0076]
The films laminated with the crimped conjugated fiber
non-woven fabric of the present invention are preferably
SF-2532 31
breathable (moisture permeable) films in order to take advantage
of the breathability of the crimped conjugated fiber non-woven
fabric. Various known breathable films may be used, with examples
including films of moisture permeable thermoplastic elastomers
5 such as polyurethane elastomers, polyester elastomers and
polyamide elastomers; and porous films obtained by stretching
thermoplastic resin films containing inorganic or organic fine
particles to create pores in the films. Preferred thermoplastic
resins for the porous films are high-pressure low-density
10 polyethylenes, linear low-density polyethylenes (LLDPE),
high-density polyethylenes, polypropylenes, polypropylene
random copolymers and compositions containing these polyolefins,
[0077]
The laminates with the breathable films are cloth-like
15 composite materials having bulkiness and softness of the crimped
conjugated fiber non-woven fabric of the present invention and
very high water resistance.
[0078]

20 The non-woven fabric of the present invention may be
produced by any known process while still achieving the
advantageous effects of the present invention. A preferred
production process is described below.
[0079]
SF-2532 32
I?
The non-woven fabric of the present invention is preferably
produced through:
(1) a step in which compositions prepared by adding a
predetermined amount of the fatty acid amide to the olefin polymer
5 (A) and/or the olefin polymer (B) that are raw materials for the
portion (a) and the portion (b) respectively are separately molten
in at least two extruders and are spun from a composite spinning
nozzle into conjugated fibers;
(2) a step in which the conjugated fibers are quenched, then
10 drawn and attenuated to develop crimps, and the crimped conjugated
fibers are deposited on a collecting belt to a desired thickness;
and
(3) a step in which the deposited conjugated fibers are
entangled.
15 This process is called a spunbonding process.
[0080]
Step (1)
In this step, known extruders and composite spinning nozzles
may be used. The melting temperature is not particularly limited
20 but is preferably higher by approximately 50°C than the melting
point of the olefin polymer. The spinnability in this step is
evaluated based on the presence or absence of fiber breakage within
a predetermined time.
[0081]
SF-2532 33
Step (2)
In this step, the molten fibers are preferably quenched by
blowing air. The air temperature may be 10 to 40°C. The quenched
fibers may be controlled to a desired diameter by the tensile force
5 of blowing air. The quenched fibers develop crimps. The
collecting belt may be conventional but is preferably one that
is capable of conveying the crimped fibers, for example a belt
conveyer.
[0082]
10 Step (3)
The entanglement treatment in this step may be performed
for example by applying water jet or ultrasonic wave to the
deposited crimped conjugated fibers (hereinafter, also referred
to simply as "fibers") or by thermally fusion bonding the fibers
15 by embossing or hot air.
[0083]
In the present invention, it is particularly preferable that
the crimped conjugated fibers are embossed, whereby a non-woven
fabric having excellent strength is obtained. The embossing is
20 carried out under conditions such that the embossed area
percentage is 3 to 30%. The embossed area percentage represents
the total area of emboss relative to the total area of the non-woven
fabric. Reducing the embossed area provides a non-woven fabric
with excellent softness. Increasing the embossed area gives a
SF-2532 34
non-woven fabric having excellent rigidity and mechanical
strength.
[0084]
The embossing temperature is preferably controlled
5 depending on the melting points of the portions (a) and (b) . For
the propylene polymer, the embossing temperature is usually in
the range of 100 to 150°C.
EXAMPLES
10 [0085]
The present invention will be described in greater detail
by examples hereinbelow without limiting the scope of the
invention.
[0086]
15 The propylene polymers used in Examples and Comparative
Examples of the present invention are listed below.
[0087]
(1) Propylene polymer (A) [propylene homopolymer]
Prime Polypro S119 manufactured by Prime Polymer Co., Ltd.;
20 melting point: 156°C, MFR: 62 g/10 min, Mw/Mn: 2.92, Mz/Mw: 2.35
(A2-1).
[0088]
(2) Propylene/a-olefin random copolymer (B)
[propylene/ethylene random copolymer]
SF-2532 35
P
Prime Polypro S229R manufactured by Prime Polymer Co., Ltd.;
melting point: 143°C, MFR: 62 g/10 min, Mw/Mn: 2.50, Mz/Mw: 2.10,
ethylene content: 3.0% by weight (4.5 mol%) (B2-1).
[0089]
5 (3) Propylene polymer (A) [propylene homopolymer]
NOVATEC PP SAO6A manufactured by Japan Polypropylene Corporation;
melting point: 167°C, MFR: 60 g/10 min, Mw/Mn: 2.92, Mz/Mw: 2.33
(A2-2).
[0090]
10 The physical properties of the crimped conjugated
continuous fibers and non-woven fabric obtained in Examples and
Comparative Examples of the present invention were measured by
the following methods.
[0091]
15 (1) Number of crimps
The number of crimps was measured in accordance with JIS
L 1015.
[0092]
(2) KOSHI value
20 Measurement in each of tensile, shearing, compression,
surface friction and bending tests was carried out on knit
high-sensitivity conditions as measurement conditions by KES-FB
System manufactured by Kato tech Co., Ltd. The measurement
results were obtained as KOSHI values by measurement on knit
SF-2532 36
P.
underwear (summer) conditions. A lower KOSHI value exhibits
superior softness.
[0093]
(3) SHARI value
5 Measurement in each of tensile, shearing, compression,
surface friction and bending tests was carried out on knit
high-sensitivity conditions as measurement conditions by KES-FB
System manufactured by Kato tech Co., Ltd. The measurement
results were obtained as SHARI values by measurement on knit
10 underwear (summer) conditions. A lower SHARI value exhibits
superior surface smoothness and softness.
[0094]
(4) FUKURAMI value
Measurement in each of tensile, shearing, compression,
15 surface friction and bending tests was carried out on knit
high-sensitivity conditions as measurement conditions by KES-FB
System manufactured by Kato tech Co., Ltd. The measurement
results were obtained as FUKURAMI values by measurement on knit
underwear (summer) conditions. A higher FUKURAMI value exhibits
20 a larger thickness and superior softness.
[0095]
(5) Sensory evaluation
Using samples of 20 cm per side of obtained non-woven fabrics,
sensory evaluation for softness was carried out by seven persons
SF-2532 37
r
in total of four women and three men in a thermostatic chamber
at 25°C. The evaluation was made such that each person randomly
touched each sample and graded each sample based on a scale of
10, and the average value of the scores of each sample by the seven
5 persons was calculated (the figures after the decimal fractions
are omitted) , The way of the touching by each person was left
to the judgment of the person. A sample with a higher score was
determined to be superior in softness.
[0096]
10 (6) Fuzz evaluation
The fuzz weights per unit area (cm^) of the obtained
non-woven fabrics were measured by the following method. A
smaller fuzz weight indicates a smaller amount of generated fuzz,
which is better.
15 [0097]

1) Ink Rud Tester (Danilee Co)
2) Double coated tape: ST-416P (50 mm x 30 m), Sumitomo 3M
Limited, 3187C
20 3) Acrylic pressure sensitive adhesive tape (single coated
tape: Scotch® surface protection tape manufactured by Sumitomo
3M Limited)
4) Sandpaper: 320 grids (brown), width: 2 inches
5) Weight: dimension; 5 x 15 x 3.5 cm, weight; 2200 g
SF-2532 38
J?
[0098]

1) Double coated tapes of about 15 mm in length are stuck on
the non-measuring surface of a sample in MD and CD directions.
5 2) The sample is cut into a size of 4 cm x 11 cm.
3) Two single coated pressure sensitive adhesive tapes of about
19 cm are prepared.
4) The single coated pressure sensitive adhesive tapes are cut,
followed by being stuck on release paper of 14 x 15 cm.
10 5) The measuring device is provided with the sandpaper and is
started to accomplish 43 to-and-fro movements per minute of the
sandpaper after setting a counter at 20.
6) The sandpaper is detached to remove fuzz with one single
coated pressure sensitive adhesive tape.
15 7) The other tape is put on the test piece and the weight is
put thereon for 20 seconds.
8) The weight of the fuzz before and after the adhesion of the
fuzz is measured, and a fuzz weight per unit area (cm^) is measured.
[0099]
20 (7) Uniformity index evaluation
The average value of the uniformity indices (n = 5) of the
obtained non-woven fabrics was obtained as a uniformity index
value using a formation tester FMT-MIII manufactured by NOMURA
SHOJI CO., LTD. A lower uniformity index value indicates better
SF-2532 39
P
uniformity.
[0100]
A uniformity index (V) is represented by V = lOa/E. or is
the standard deviation of the inconsistencies in density of a
5 non-woven fabric, and E is obtained by measuring the light
transmittance (T) of the non-woven fabric. E is represented by
E = 2 - log T, and when the transmittance is almost 100% (poor
uniformity) , E « 0 is established and V indicates an infinitely
large value,
10 [0101]
(8) Visibility evaluation
Samples of 20 cm per side of the obtained non-woven fabrics
were put on black paper and visibility evaluation for the samples
was carried out by seven persons in total of four women and three
15 men in a thermostatic chamber at 25°C. The evaluation was made
such that each person graded each sample based on a scale of 5,
and the average value of the scores of each sample by the seven
persons was calculated (the figures after the decimal fractions
are omitted) . The way of looking by each person was left to the
20 judgment of the person. A sample with a higher score was
determined to be superior in visibility.
[0102]
[Example 1]
A composition prepared by adding 1 part by weight of stearic
SF-2532 40
P
acid amide to 100 parts by weight of A2-1 described above was used
in a core, while a composition prepared by adding 1 part by weight
of stearic acid amide to 100 parts by weight of B2-1 described
above was used in a sheath. The compositions were melt-spun by
5 spunbonding method.
[0103]
Single-screw extruders were used and the compositions were
molten at 200°C.
[0104]
10 The compositions were spun into continuous fibers in which
the mass ratio of a core hi to a sheath h2 was 20:80. In this
case, the fiber rate was 2060 m/min and the fineness was 2. 3 denier.
[0105]
The resultant eccentric core-sheath crimped conjugated
15 continuous fibers that were melt-spun were deposited on a
collecting surface to form a non-woven fabric. The non-woven
fabric was embossed at 125°C by quilt embossment. The embossed
area percentage was 9.7%. The embossed non-woven fabric had a
basis weight of 25 g/m^. The resultant crimped conjugated
20 continuous fibers and non-woven fabric were evaluated for
properties by the above-described methods.
[0106]
The measurement results are set forth in Table 1.
[0107]
SF-2532 41
I?
[Example 2]
Crimped conjugated continuous fibers and a non-woven fabric
were obtained in the same manner as in Example 1, except that the
compositions used in Example 1 were changed to compositions
5 prepared by adding 1 part by weight of oleic acid amide to 100
parts by weight of A2-1 and B2-1, respectively. The measurement
results for the crimped conjugated continuous fibers and the
non-woven fabric are set forth in Table 1.
[0108]
10 [Example 3]
Crimped conjugated continuous fibers and a non-woven fabric
were obtained in the same manner as in Example 1, except that the
compositions used in Example 1 were changed to compositions
prepared by adding 1 part by weight of N-oleylpalmitic acid amide
15 to 100 parts by weight of A2-1 and B2-1, respectively. The
measurement results for the crimped conjugated continuous fibers
and the non-woven fabric are set forth in Table 1.
[0109]
[Comparative Example 1]
20 Crimped conjugated continuous fibers and a non-woven fabric
were obtained in the same manner as in Example 1, except that the
compositions used in Example 1 were changed to A2-1 and B2-1
neither of which contained fatty acid amide. The measurement
results for the crimped conjugated continuous fibers and the
SF-2532 42
non-woven fabric are set forth in Table 1.
[0110]
[Comparative Example 2]
Crimped conjugated continuous fibers and a non-woven fabric
5 were obtained in the same manner as in Example 1, except that the
compositions used in Example 1 were changed to compositions
prepared by adding 1 part by weight of erucic acid amide to 100
parts by weight of A2-1 and B2-1, respectively. The measurement
results for the crimped conjugated continuous fibers and the
10 non-woven fabric are set forth in Table 1.
[0111]
[Comparative Example 3]
Crimped conjugated continuous fibers and a non-woven fabric
were obtained in the same manner as in Example 1, except that the
15 compositions used in Example 1 were changed to A2-2 which contained
no fatty acid amide for a core and B2-1 which contained no fatty
acid amide for a sheath. The measurement results for the crimped
conjugated continuous fibers and the non-woven fabric are set
forth in Table 1.
20 [0112]
[Table 1]
SF-2532 43
Table 1 ^
Additive
Production
conditions
Polymers
(A) and (B)
Conjugated
fibers
Non-woven
fabric
Properties
Type of additive
Amount of
additive
Part by
weight
Fiber bonding method
(embossment type)
Bonded (embossed) area
percentage
Difference
between
melting
points
MFR
AMZ/MW
°C
Polymer (A)
Polymer (B)
-
Resin configuration
Basis
weight
Number of
crimps
Softness
evaluation
KES
Sensory
evaluation
Fuzz
evaluation
Uniformity
index
g/m'
crimps/25
mm
KOSHI
SHARI
FUKURAMI
Score
g/cm^
-
Visibility-
Examples
Example 1
Stearic
acid amide
1.0
Quilt
9.7
13
62
62
0.25
h-PP/r-PP
25
23.1
6.68
-1.69
11.34
8
0.07
358
4
Example 2
Oleic acid
amide
1.0
Quilt
9.7
13
62
62
0.25
h-PP/r-PP
25
20.6
7.34
-1.04
11.93
8
0.05
315
4
Example 3
Oleylpalmi
tic acid
cimide
1.0
Quilt
9.7
13
62
62
0.25
h-PP/r-PP
25
23.5
7.03
-1.69
11.73
8
0.06
344
4
Comparative Exsimples
Comparative
Example 1
None
0.0
Quilt
9.7
13
62
62
0.25
h-PP/r-PP
25
15.0
7.53
-0.96
10.35
6
0.16
463
2
Comparative
Example 2
Erucic acid
amide
1.0
Quilt
9.7
13
62
62
0.25
h-PP/r-PP
25
17.5
7.94
-0.24
8.51
6
0.12
432
2
Comparative
Example 3
None
0.0
Quilt
9.7
24
60
60
0.23
h-PP/r-PP
25
60.0
7.44
-0.92
10.86
7
0.20
585
1
SF-2532 44
INDUSTRIAL APPLICABILITY
[0113]
The non-woven fabric according to the present invention has
excellent properties such as spinnability, strength, softness and
5 water resistance and is useful in side gathers, back sheets, top
sheets and waist parts of disposable diapers or sanitary napkins.
REFERENCE SIGNS LIST
[0114]
10 10 - portion (a)
20 - portion (b)

SF-2532 45
CLAIMS T0454«»
1. A crimped conjugated fiber having a crimpable jj 5 DEC 2013
cross-sectional configuration, wherein a cross section of the
5 fiber comprises at least two portions: a portion (a) and a portion
(b) ; the mass ratio of the portion (a) to the portion (b) [ (a) : (b) ]
is in the range of 10:90 to 60:40; the portion (a) comprises an
olefin polymer (A) and the portion (b) comprises an olefin polymer
(B); the olefin polymer (A) differs from the olefin polymer (B)
10 in at least any one of Mz/Mw, melting point and MFR; and a fatty
acid amide having 19 or less carbon atoms is added to the olefin
polymer (A) and/or the olefin polymer (B).
2. The crimped conjugated fiber according to claim 1,
15 wherein the difference between the melting points of the olefin
polymer (A) and the olefin polymer (B) is less than 20°C.
3. The crimped conjugated fiber according to claim 1,
wherein the blended amount of the fatty acid amide having 19 or
20 less carbon atoms is in the range of 0.1 to 10 parts by weight
based on 100 parts by weight of the olefin polymer (A) and/or the
olefin polymer (B).
4. The crimped conjugated fiber according to claim 1,
SF-2532 46
wherein the crimped conjugated fiber has an eccentric core-sheath
configuration in which the portion (a) is a core (a') and the
portion (b) is a sheath (b').
5 5. The crimped conjugated fiber according to claim 1,
wherein the olefin polymer (A) and the olefin polymer (B) are a
propylene polymer (Al) and a propylene polymer (Bl), respectively.
6. The crimped conjugated fiber according to claim 5,
10 wherein the propylene polymer (Al) and the propylene polymer (Bl)
are a propylene homopolymer (A2) and a propylene/a-olefin
copolymer (B2), respectively.
7. The crimped conjugated fiber according to claim 1,
15 wherein the fatty acid amide is stearic acid amide, oleic acid
amide, or oleylpalmitic acid amide.
8. A non-woven fabric comprising the crimped conjugated
fiber according to any one of claims 1 to 7.
20
9. A non-woven fabric laminate comprising a layer
configuration including at least two or more layers, wherein at
least one layer of the two or more layers is the non-woven fabric
according to claim 8.
SF-2532 47
10. An absorbent article comprising the non-woven fabric
according to claim 8, wherein the non-woven fabric is used in a
top sheet and/or a second sheet,
5
11. An absorbent article comprising the non-woven fabric
according to claim 8, wherein the non-woven fabric is used in a
sheet in which an absorber is wrapped.
10 12. A non-woven fabric comprising a crimped conjugated
fiber having a crimpable cross-sectional configuration, wherein
a cross section of the fiber comprises at least two portions: a
portion (a) and a portion (b); the mass ratio of the portion (a)
to the portion (b) [(a):(b)] is in the range of 10:90 to 60:40;
15 the portion (a) comprises an olefin polymer (A) and the portion
(b) comprises an olefin polymer (B) ; the olefin polymer (A) differs
from the olefin polymer (B) in at least any one of Mz/Mw, melting
point and MFR; and the number of crimps is 18 or more [per 25 mm] ,
the non-woven fabric having a KOSHI value of 7,4 or less in
20 accordance with KES and a uniformity index (V) of 420 or less.
13. A non-woven fabric laminate comprising a layer
configuration including at least two or more layers, wherein at
least one layer of the two or more layers is the non-woven fabric
P
according to claim 12.
14. An absorbent article comprising the non-woven fabric
according to claim 12, wherein the non-woven fabric is used in
5 a top sheet and/or a second sheet.
15. An absorbent article comprising the non-woven fabric
according to claim 12, wherein the non-woven fabric is used in
a sheet in which an absorber is wrapped.