U.S. patent application number 14/763994 was filed with the patent office on 2015-12-24 for fibrous nonwoven fabric.
This patent application is currently assigned to IDEMITSU KOSAN CO., LTD.. The applicant listed for this patent is IDEMITSU KOSAN CO., LTD.. Invention is credited to Yohei KOORI, Yutaka MINAMI, Tomoaki TAKEBE.
Application Number | 20150368836 14/763994 |
Document ID | / |
Family ID | 51262392 |
Filed Date | 2015-12-24 |
United States Patent
Application |
20150368836 |
Kind Code |
A1 |
KOORI; Yohei ; et
al. |
December 24, 2015 |
FIBROUS NONWOVEN FABRIC
Abstract
Provided is a fibrous nonwoven fabric including a resin
composition (C) containing a high-crystalline polyolefin (A) and a
low-crystalline polyolefin (B), wherein a half-crystallization time
(t.sub.c) of the resin composition (C) is 1.2 to 2.0 times a
half-crystallization time (t.sub.a) of the high-crystalline
polyolefin (A).
Inventors: |
KOORI; Yohei; (Ichihara-shi,
JP) ; TAKEBE; Tomoaki; (Chiba-shi, JP) ;
MINAMI; Yutaka; (Chiba-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
IDEMITSU KOSAN CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
IDEMITSU KOSAN CO., LTD.
Tokyo
JP
|
Family ID: |
51262392 |
Appl. No.: |
14/763994 |
Filed: |
January 30, 2014 |
PCT Filed: |
January 30, 2014 |
PCT NO: |
PCT/JP2014/052164 |
371 Date: |
July 28, 2015 |
Current U.S.
Class: |
442/401 ;
264/172.17; 442/334 |
Current CPC
Class: |
D10B 2509/026 20130101;
D04H 3/016 20130101; D04H 1/4291 20130101; D04H 3/007 20130101;
Y10T 442/681 20150401; D10B 2501/00 20130101; Y10T 442/608
20150401; D01D 5/08 20130101 |
International
Class: |
D04H 1/4291 20060101
D04H001/4291; D01D 5/08 20060101 D01D005/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 30, 2013 |
JP |
2013-016250 |
Claims
1. A fibrous nonwoven fabric comprising a resin composition (C)
comprising a high-crystalline polyolefin (A) and a low-crystalline
polyolefin (B), the fibrous nonwoven fabric satisfying the
following conditions (1) and (2): (1) a half-crystallization time
(t.sub.a) of the high-crystalline polyolefin (A) and a
half-crystallization time (t.sub.b) of the low-crystalline
polyolefin (B) satisfy a relation of t.sub.a<t.sub.b; and (2) a
half-crystallization time (t.sub.c) of the resin composition (C) is
1.2 to 2.0 times the half-crystallization time (t.sub.a) of the
high-crystalline polyolefin (A).
2. The fibrous nonwoven fabric according to claim 1, wherein a
fineness of fibers constituting the fibrous nonwoven fabric is 0.2
to 1.3 deniers.
3. The fibrous nonwoven fabric according to claim 2, wherein the
fineness of fibers constituting the fibrous nonwoven fabric is 0.2
to 0.8 deniers.
4. The fibrous nonwoven fabric according to claim 1, wherein an
initial elastic modulus of the high-crystalline polyolefin (A) is
500 to 2,000 MPa, and an initial elastic modulus of the
low-crystalline polyolefin (B) is 5 MPa or more and less than 500
MPa.
5. The fibrous nonwoven fabric according to claim 1, wherein when
molding the fibrous nonwoven fabric, molding is performed in a
discharge amount per hole of 0.1 to 0.5 g/min.
6. A spunbonded nonwoven fabric constituted of fibers having a
fineness of 0.2 to 1.0 denier.
7. The fibrous nonwoven fabric according to claim 2 wherein an
initial elastic modulus of the high-crystalline polyolefin (A) is
500 to 2,000 MPa, and an initial elastic modulus of the low
crystalline polyolefin (B) is 5 MPa or more and less than 500
MPa.
8. The fibrous nonwoven fabric according to claim 3, wherein an
initial elastic modulus of the high-crystalline polyolefin (A) is
500 to 2,000 MPa, and an initial elastic modulus of the low
crystalline polyolefin (B) is 5 MPa or more and less than 500
MPa.
9. The fibrous nonwoven fabric according to claim 2, wherein when
molding the fibrous nonwoven fabric, molding is performed in a
discharge amount per hole of 0.1 to 0.5 g/min.
10. The fibrous nonwoven fabric according to claim 3, wherein when
molding the fibrous nonwoven fabric, molding is performed in a
discharge amount per hole of 0.1 to 0.5 g/min.
11. The fibrous nonwoven fabric according to claim 4, wherein when
molding the fibrous nonwoven fabric, molding is performed in a
discharge amount per hole of 0.1 to 0.5 g/min.
Description
TECHNICAL FIELD
[0001] The present invention relates to a fibrous nonwoven fabric
using a polyolefin material.
BACKGROUND ART
[0002] In recent years, polyolefin-based fibers and nonwoven
fabrics are used for various applications, such as a disposable
diaper, a sanitary product, a hygienic product, a clothing
material, a bandage, a packaging material, etc. The fibers and
nonwoven fabrics are often used for applications in which they come
into direct contact with the body, and thus, in recent years, a
required performance regarding good wear feeling to the body and
hand touch feeling are being more increased. For this reason, with
respect to the nonwoven fabrics, technological development related
to an improvement of texture for good wear feeling, reduction in
basis weight for weight reduction of products, and the like is
demanded.
[0003] However, in producing a nonwoven fabric using a
conventionally used polyolefin-based resin by a spunbond method,
for the purpose of aiming to reduce fiber diameter, if a discharge
amount per hole is decreased, or a spinning speed is increased, end
breakage occurs frequently, so that stable spinnability is not
obtained. When the end breakage occurs, the broken fiber catches up
surrounding fibers to cause a roping phenomenon, or the nonwoven
fabric in a part where the end breakage occurs or a part where the
roped fiber falls leads to a defect or uneven basis weight, and
therefore, defective quality of the nonwoven fabric is brought. For
this reason, it is desired to make both stable spinnability free
from the occurrence of end breakage and reducing the fiber diameter
compatible with each other.
CITATION LIST
Patent Literature
[0004] PTL 1: WO2011/030893
SUMMARY OF INVENTION
Technical Problem
[0005] Here, PTL 1 discloses a spunbonded nonwoven fabric using a
resin composition containing a low-crystalline polypropylene and a
high-crystalline polypropylene; however, from the viewpoint of
providing a nonwoven fabric having more excellent flexibility and
higher strength, fibers constituting the nonwoven fabric are
required to more reduce fiber diameter.
[0006] In view of the foregoing circumstances, the present
invention has been made, and its object is to reduce fiber diameter
of fibers constituting a fibrous nonwoven fabric using a polyolefin
resin composition while preserving spinning stability.
Solution to Problem
[0007] The present inventors made extensive and intensive
investigations. As a result, it has been found that the
above-described problem is solved by using a polyolefin resin
composition having a specified crystallization rate.
[0008] Specifically, the present invention provides the
following.
1. A fibrous nonwoven fabric including a resin composition (C)
containing a high-crystalline polyolefin (A) and a low-crystalline
polyolefin (B), the fibrous nonwoven fabric satisfying the
following conditions (1) and (2):
[0009] (1) a half-crystallization time (t.sub.a) of the
high-crystalline polyolefin (A) and a half-crystallization time
(t.sub.b) of the low-crystalline polyolefin (B) satisfy a relation
of t.sub.a<t.sub.b; and
[0010] (2) a half-crystallization time (t.sub.c) of the resin
composition (C) is 1.2 to 2.0 times the half-crystallization time
(t.sub.a) of the high-crystalline polyolefin (A).
2. The fibrous nonwoven fabric according to the above item 1,
wherein a fineness of fibers constituting the fibrous nonwoven
fabric is 0.2 to 1.3 deniers. 3. The fibrous nonwoven fabric
according to the above item 2, wherein the fineness of fibers
constituting the fibrous nonwoven fabric is 0.2 to 0.8 deniers. 4.
The fibrous nonwoven fabric according to any one of the above items
1 to 3, wherein an initial elastic modulus of the high-crystalline
polyolefin (A) is 500 to 2,000 MPa, and an initial elastic modulus
of the low-crystalline polyolefin (B) is 5 MPa or more and less
than 500 MPa. 5. The fibrous nonwoven fabric according to any one
of the above items 1 to 4, wherein when molding the fibrous
nonwoven fabric, molding is performed in a discharge amount per
hole of 0.1 to 0.5 g/min. 6. A spunbonded nonwoven fabric
constituted of fibers having a fineness of 0.2 to 1.0 denier.
Advantageous Effects of Invention
[0011] According to the present invention, in a fibrous nonwoven
fabric using a polyolefin resin composition, the reduction of
diameter of fibers constituting the nonwoven fabric can be achieved
while preserving spinning stability.
DESCRIPTION OF EMBODIMENTS
<First Invention>
[0012] A fibrous nonwoven fabric of a first invention is composed
of a resin composition containing a high-crystalline polyolefin (A)
and a low-crystalline polyolefin (B). It is to be noted that the
low-crystalline polyolefin (B) as referred to in the present
invention means a crystalline polyolefin having a longer
half-crystallization time than the high-crystalline polyolefin (A).
That is, a half-crystallization time (t.sub.a) of the
high-crystalline polyolefin (A) and a half-crystallization time
(t.sub.b) of the low-crystalline polyolefin (B) satisfy a relation
Of t.sub.a<t.sub.b.
[High-Crystalline Polyolefin (A)]
[0013] The high-crystalline polyolefin (A) which is used in the
first invention is not particularly limited in terms of a kind
thereof so long as it satisfies a condition (2) regarding a resin
composition (C) as described later. Examples thereof include
polyethylene, a propylene homopolymer, an ethylene-propylene
copolymer, an ethylene-.alpha.-olefin copolymer, a
propylene-.alpha.-olefin copolymer, an .alpha.-olefin homopolymer,
a copolymer of plural .alpha.-olefins, and the like. This
.alpha.-olefin is preferably one having 4 to 24 carbon atoms, more
preferably one having 4 to 12 carbon atoms, and especially
preferably one having 4 to 8 carbon atoms.
[0014] As for the above-described high-crystalline polyolefin (A),
its initial elastic modulus is preferably 500 to 2,000 MPa, more
preferably 600 to 2,000 MPa, and still more preferably 700 to 1,800
MPa. The initial elastic modulus as referred to in this description
is one measured by the following measuring method.
[Measuring Method of Initial Elastic Modulus]
[0015] A press sheet having a thickness of 1 mm was fabricated. A
test piece was sampled from the resulting press sheet in conformity
with JIS K7113 (2002) No. 2-1/2. Using a tensile tester (AUTOGRAPH
AG-1, manufactured by Shimadzu Corporation), the test piece was set
at an initial length L0 of 40 mm, stretched at a tensile speed of
100 mm/min, and measured for a strain and a load in the stretching
process, and the initial elastic modulus was calculated according
to the following expression.
Initial elastic modulus(N)=(Load(N) at a strain of 5%)/0.05
[0016] It is to be noted that the half-crystallization time
(t.sub.a, t.sub.b, and t.sub.c) as referred to in this description
means one measured by the following measuring method.
[Measuring Method of Half-Crystallization Time]
[0017] The measurement is made using FLASH DSC (manufactured by
Mettler-Toledo International Inc.) in the following method.
(1) A sample is melted by heating at 230.degree. C. for 2 minutes
and then cooled to 25.degree. C. at a rate of 2,000.degree. C./sec,
and a time change of heating value in an isothermal crystallization
process at 25.degree. C. is measured.
[0018] In the conventional DSC measurement, since the
above-described abrupt cooling could not be performed,
crystallization started in the cooling process, so that accurate
evaluation of the isothermal crystallization in the neighborhood of
room temperature could not be achieved.
(2) When an integrated value of heating value from start of the
isothermal crystallization to completion of the crystallization is
defined as 100%, a time from start of the isothermal
crystallization until the integrated value of heating value reaches
50% is defined as the half-crystallization time.
[Low-Crystalline Polyolefin (B)]
[0019] The above-described low-crystalline polyolefin (B) is not
particularly limited in terms of a kind thereof so long as it has a
longer half-crystallization time than the high-crystalline
polyolefin (A) as described above. Examples thereof include
polyethylene, a propylene homopolymer, an ethylene-propylene
copolymer, a propylene-.alpha.-olefin copolymer, an .alpha.-olefin
homopolymer, a copolymer of plural .alpha.-olefins, and the like.
This .alpha.-olefin is preferably one having 4 to 24 carbon atoms,
more preferably one having 4 to 12 carbon atoms, and especially
preferably one having 4 to 8 carbon atoms.
[0020] As for the above-described low-crystalline polyolefin (B),
its initial elastic modulus is preferably 5 MPa or more and less
than 500 MPa, more preferably 10 to 400 MPa, and still more
preferably 20 to 300 MPa. The initial elastic modulus of the
low-crystalline polyolefin (B) can be measured in the same manner
as that in the above-described high-crystalline polyolefin (A).
[0021] In the case where the high-crystalline polyolefin (A) is a
general-purpose polypropylene, the low-crystalline polyolefin (B)
is preferably a low-crystalline polypropylene satisfying the
following condition (a), and more preferably a low-crystalline
polypropylene satisfying all of the following conditions (a) to
(f).
(a) [mmmm]=20 to 60 mol %
[0022] As for the above-described low-crystalline polypropylene,
its [mmmm] (mesopentad fraction) is 20 to 60 mol %. When the [mmmm]
is 20 mol % or more, solidification after melting is fast,
stickiness of the fibers is suppressed, and attachment onto a
wind-up roll is hardly caused, and therefore, continuous molding
becomes easy. In addition, when the [mmmm] is 60 mol % or less, a
degree of crystallization is lowered, and therefore, end breakage
is hardly caused, and furthermore, a nonwoven fabric having a soft
touch feeling is obtained. From such viewpoints, the [mmmm] of the
above-described low-crystalline polypropylene is more preferably 30
to 50 mol %, and still more preferably 40 to 50 mol %.
(b) [rrrr]/(1-[mmmm]).ltoreq.0.1
[0023] As for the above-described low-crystalline polypropylene,
its [rrrr]/(1-[mmmm]) is preferably 0.1 or less. The
[rrrr]/(1-[mmmm]) is an index indicating the uniformity of
regularity distribution of the low-crystalline polypropylene. When
this value is small, the resultant does not become a mixture of a
high-stereoregular polypropylene and an atactic polypropylene, as
in the conventional polypropylene which is produced using an
existent catalyst system, and stickiness is hardly caused. From
such a viewpoint, the [rrrr]/(1-[mmmm]) of the above-described
low-crystalline polypropylene is more preferably 0.05 or less, and
still more preferably 0.04 or less.
(c)[.sub.rmrm]>2.5 mol %
[0024] As for the above-described low-crystalline polypropylene,
its [rmrm] (racemic-meso-racemic-meso pentad fraction) is
preferably more than 2.5 mol %. If the [rmrm] is 2.5 mol % or less,
random properties of the low-crystalline polypropylene are reduced,
the degree of crystallization is increased due to crystallization
by an isotactic polypropylene block chain, end breakage is caused,
and furthermore, a soft touch feeling is not obtained in the
resulting nonwoven fabric. The [rmrm] of the above-described
low-crystalline polypropylene is more preferably 2.6 mol % or more,
and still more preferably 2.7 mol % or more. An upper limit thereof
is usually about 10 mol %.
(d) [mm].times.[rr]/[mr].sup.2.ltoreq.2.0
[0025] As for the above-described low-crystalline polypropylene,
its [mm] (mesotriad fraction).times.[rr] (racemic triad
fraction)/[mr] (meso-racemic triad fraction).sup.2 is preferably
2.0 or less. The [mm].times.[rr]/[mr].sup.2 indicates an index of
random properties of the polymer, and when the
[mm].times.[rr]/[mr].sup.2 is smaller, the random properties become
higher, the frequency of end breakage is reduced, and a nonwoven
fabric having a soft touch feeling is obtained. When this value is
2.0 or less, end breakage is not caused in fibers obtained by
spinning, and a nonwoven fabric having a good soft touch feeling is
obtained. From such a viewpoint, the [mm].times.[rr]/[mr].sup.2 of
the above-described low-crystalline polypropylene is more
preferably more than 0.25 and 1.8 or less, and still more
preferably 0.5 to 1.5.
(e) Weight average molecular weight(Mw)=10,000 to 200,000
[0026] As for the above-described low-crystalline polypropylene,
its weight average molecular weight is preferably 10,000 to
200,000. When the weight average molecular weight is 10,000 or
more, the viscosity of the low-crystalline polypropylene is not
excessively low but is appropriate, and therefore, end breakage on
the occasion of spinning is suppressed. In addition, when the
weight average molecular weight is 200,000 or less, the viscosity
of the low-crystalline polypropylene is not excessively high, and
spinnability is improved. From such a viewpoint, the weight average
molecular weight of the above-described low-crystalline
polypropylene is more preferably 30,000 to 100,000, and still more
preferably 40,000 to 80,000.
(f) Molecular weight distribution (Mw/Mn)<4.0
[0027] As for the low-crystalline polypropylene which is used in
the first invention, its molecular weight distribution (Mw/Mn) is
preferably less than 4.0. When the molecular weight distribution is
less than 4.0, the generation of stickiness in the fibers obtained
by spinning is suppressed. The molecular weight distribution
(Mw/Mn) of the above-described low-crystalline polypropylene is
more preferably 3.0 or less, and still more preferably 2.5 or
less.
[0028] By using the low-crystalline polypropylene satisfying the
above-described conditions (a) to (f) together with the
above-described general-purpose polypropylene, a raw material
compensating disadvantages of the general-purpose polypropylene and
suitable for the production of a target nonwoven fabric is
obtained.
[0029] It is to be noted that the low-crystalline polypropylene
satisfying the above-described condition (a) may also be a
copolymer using other comonomer than propylene so long as it
satisfies the condition (2) regarding the resin composition (C) as
described later. In this case, the amount of the comonomer is
usually 2% by mass or less. Examples of the comonomer include
ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene,
1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene,
1-octadecene, 1-eicocene, and the like. In the present invention,
one or two or more kinds of these monomers can be used.
[Resin Composition (C)]
[0030] The resin composition (C), which is a raw material of the
fibrous nonwoven fabric of the first invention, contains the
high-crystalline polyolefin (A) and the low-crystalline polyolefin
(B) as described above, and a half-crystallization time (t.sub.a)
of the resin composition (C) is 1.2 to 2.0 times the
half-crystallization time (t.sub.a) of the high-crystalline
polyolefin (A).
[0031] If the half-crystallization time (t.sub.c) is less than 1.2
times the half-crystallization time (t.sub.a), the crystallization
rate of the resin composition (C) is fast, and on the occasion of
melt molding of fibers, and the molten resin discharged from a
nozzle is immediately crystallized, and therefore, end breakage is
liable to occur, reducing the fiber diameter is difficulty
achieved, and the fiber diameter is limited to 1.7 deniers or more.
Meanwhile, if the half-crystallization time (t.sub.c) is more than
2.0 times the half-crystallization time (t.sub.a), the fiber
surface is sticky, roping (phenomenon in which the fibers stick to
each other) is generated, and stable spinning cannot be achieved.
In addition, the fibers become thick due to shrinkage, so that
reducing the fiber diameter cannot be achieved, too.
[0032] From the above-described viewpoints, the
half-crystallization time (t.sub.c) is preferably 1.2 to 1.9 times,
and more preferably 1.3 to 1.9 times the half-crystallization time
(t.sub.a).
[0033] Examples of a method of controlling the half-crystallization
time (t.sub.c) of the resin composition (C) to 1.2 times or more
the half-crystallization time (t.sub.a) of the high-crystalline
polyolefin (A) include a method of increasing a ratio of the
low-crystalline polyolefin (B) in the combination of the
high-crystalline polyolefin (A) and the low-crystalline polyolefin
(B); a method of changing the low-crystalline polyolefin (B) to one
having a longer half-crystalline time (t.sub.b); and the like.
Meanwhile, examples of a method of controlling the
half-crystallization time (t.sub.c) of the resin composition (C) to
2.0 times or less the half-crystalline time (t.sub.a) of the
high-crystalline polyolefin (A) include a method of decreasing a
ratio of the low-crystalline polyolefin (B) in the combination of
the high-crystalline polyolefin (A) and the low-crystalline
polyolefin (B); a method of changing the low-crystalline polyolefin
(B) to one having a shorter half-crystalline time (t.sub.b); and
the like.
[0034] The content of the high-crystalline polyolefin (A) in the
above-described resin composition (C) is not particularly limited
so long as it falls within the range where the condition (2)
regarding the resin composition (C) can be satisfied. In addition,
the contents of the high-crystalline polyolefin (A) and the
low-crystalline polyolefin (B) in order to satisfy the condition
(2) regarding the resin composition (C) vary depending upon what
kinds of polyolefins are selected with respect to the
high-crystalline polyolefin (A) and the low-crystalline polyolefin
(B).
[0035] As an example, in the case where the high-crystalline
polyolefin (A) is a general-purpose polypropylene, and the
low-crystalline polyolefin (B) is a low-crystalline polypropylene
satisfying the above-described initial elastic modulus, the content
of the high-crystalline polyolefin (A) in the above-described resin
composition (C) is preferably 50 to 98% by mass, and more
preferably 60 to 95% by mass.
[0036] In addition, the content of the low-crystalline polyolefin
(B) in the above-described resin composition (C) is preferably 2 to
50% by mass, and more preferably 5 to 40% by mass.
[0037] Furthermore, in the above-described resin composition (C),
the content of the low-crystalline polypropylene satisfying the
above-described initial elastic modulus is preferably 2 to 35% by
mass, and more preferably 5 to 30% by mass on the basis of a total
sum of the high-crystalline polyolefin (A) and the low-crystalline
polyolefin (B).
[0038] The above-described resin composition (C) may contain other
thermoplastic resin and various additives, such as a release agent,
etc. so long as it satisfies the above-described physical
properties.
[0039] Examples of the other thermoplastic resin include
olefin-based polymers. Specifically, examples thereof include a
polypropylene, a propylene-ethylene copolymer, a
propylene-ethylene-diene copolymer, a polyethylene, an
ethylene/.alpha.-olefin copolymer, an ethylene-vinyl acetate
copolymer, a hydrogenated styrene-based elastomer, and the like.
These may be used solely or may be used in combination of two or
more kinds thereof.
[0040] The above-described release agent refers to an additive for
improving release properties such that the molded nonwoven fabric
does not attach to a roll or a conveyor of a molding machine. The
release agent which is contained in the resin composition (C) is
called an internal release agent, and the internal release agent
refers to an additive for improving release properties of the
nonwoven fabric upon being added to the resin raw material. An
external release agent as described later refers to an additive for
improving release properties of the nonwoven fabric upon being
coated directly on a roll or a conveyor of a molding machine.
[0041] Examples of the internal release agent include organic
carboxylic acids or metal salts thereof, aromatic sulfonic acid
salts or metal salts thereof, organic phosphoric acid compounds or
metal salts thereof, dibenzylidene sorbitol or derivatives thereof,
rhodinic acid partial metal salts, inorganic fine particles, imidic
acids, amide acids, quinacridones, quinones, and mixtures
thereof.
[0042] Examples of the metal in the above-described metal salt of
an organic carboxylic acid include Li, Ca, Ba, Zu, Mg, Al, Pb, and
the like. In addition, examples of the carboxylic acid include
fatty acids, such as octylic acid, palmitic acid, lauric acid,
stearic acid, behenic acid, montanic acid, 12-hydroxystearic acid,
oleic acid, isostearic acid, ricinoleic acid, etc.; and aromatic
acids, such as benzoic acid, p-t-b-benzoic acid, etc. Specific
examples thereof include aluminum benzoate, aluminum
p-t-butylbenzoate, sodium adipate, sodium thiophenecarboxylate,
sodium pyrrolecarboxylate, and the like.
[0043] Specific examples of the above-described dibenzylidene
sorbitol or derivative thereof include dibenzylidene sorbitol,
1,3:2,4-bis(o-3,4-dimethylbenzylidene)sorbitol,
1,3:2,4-bis(o-2,4-dimethylbenzylidene)sorbitol,
1,3:2,4-bis(o-4-ethylbenzylidene)sorbitol,
1,3:2,4-bis(o-4-chlorobenzylidene)sorbitol, 1,3:2,4-dibenzylidene
sorbitol, and the like. More specifically, GELOL MD and GELOL MD-R,
all of which are manufactured by New Japan Chemical Co., Ltd., and
the like are exemplified.
[0044] Examples of the above-described rhodinic acid partial metal
salt include PINECRYSTAL KM1600, PINECRYSTAL KM1500, and
PINECRYSTAL KM1300, all of which are manufactured by Arakawa
Chemical Industries, Ltd., and the like.
[0045] Examples of the above-described inorganic fine particle
include talc, clay, mica, asbestos, glass fiber, glass flake, glass
bead, calcium silicate, montmorillonite, bentonite, graphite,
aluminum powder, alumina, silica, diatomaceous earth, titanium
oxide, magnesium oxide, pumice powder, pumice balloon, aluminum
hydroxide, magnesium hydroxide, basic magnesium carbonate,
dolomite, calcium sulfate, potassium titanate, barium sulfate,
calcium sulfite, molybdenum sulfide, and the like. In addition,
synthetic silica may be used as the silica, and examples thereof
include SYLYSIA, manufactured by Fuji Silysia Chemical Ltd.,
MIZUKASIL, manufactured by Mizusawa Industrial Chemicals, Ltd., and
the like.
[0046] Examples of the above-described amide compound include
erucic acid amide, oleic acid amide, stearic acid amide, behenic
acid amide, ethylene bisstearic acid amide, ethylene bisoleic acid
amide, stearyl erucamide, oleyl palmitamide, adipic acid dianilide,
suberic acid dianilide, and the like.
[0047] Examples of the above-described organic phosphoric metal
salt include ADEKASTAB NA-11 and ADEKASTAB NA-21, all of which are
manufactured by Adeka Corporation, and the like.
[0048] These internal release agents can be used solely or in
combination of two or more kinds thereof. In the present invention,
among these internal release agents, one selected from erucic acid
amide, dibenzylidene sorbitol,
1,3:2,4-bis(o-3,4-dimethylbenzylidene)sorbitol,
1,3:2,4-bis(o-2,4-dimethylbenzylidene)sorbitol,
1,3:2,4-bis(o-4-ethylbenzylidene)sorbitol,
1,3:2,4-bis(o-4-chlorobenzylidene)sorbitol, and
1,3:2,4-dibenzylidene sorbitol is preferred.
[0049] In the resin composition (C), the content of the internal
release agent is preferably 10 to 10,000 ppm by mass, and more
preferably 100 to 5,000 ppm by mass on the basis of the resin
mixture from which the additives are eliminated. When the content
of the internal release agent is 10 ppm by mass or more, the
function as the release agent is revealed, whereas when it is
10,000 ppm by mass or less, a balance between the function as the
release agent and the economy becomes good.
[0050] As the additive other than the release agent, any
conventionally known additives may be blended. Examples of the
additive include a foaming agent, a crystal nucleating agent, a
weatherability stabilizer, a UV absorber, a light stabilizer, a
heat resistance stabilizer, an antistatic agent, a flame retardant,
a synthetic oil, a wax, an electric property-improving agent, a
slip inhibitor, an anti-blocking agent, a viscosity-controlling
agent, a coloring inhibitor, a defogging agent, a lubricant, a
pigment, a dye, a plasticizer, a softening agent, an age resistor,
a hydrochloric acid-absorbing agent, a chlorine scavenger, an
antioxidant, and an antitack agent, and the like.
[Nonwoven Fabric]
[0051] The nonwoven fabric of the first invention is one obtained
by using the above-described resin composition (C) as the raw
material, and preferably one produced by a spunbond method.
Typically, in the spunbond method, the nonwoven fabric is produced
in such a manner that a melt-kneaded resin composition is spun,
stretched, and opened to form continuous long fibers, and
subsequently, in a continued step, the continuous long fibers are
accumulated on a moving collecting surface and entangled. In this
method, a nonwoven fabric can be produced continuously, and the
resulting nonwoven fabric has large strength because fibers
constituting the nonwoven fabric are stretched continuous long
fibers.
[0052] As the spunbond method of producing the fibrous nonwoven
fabric of the first invention, conventionally known methods can be
adopted. Fibers can be produced by extruding a molten polymer, for
example, from a large nozzle with several thousands of holes or a
group of small nozzles having, for example, about 40 holes. After
discharged from the nozzle, molten fibers are cooled by a
cross-flow cooling air system, drawn away from the nozzle, and
stretched by high-speed airflow. Generally, there are two kinds of
air-damping methods, and the both use a venturi effect. In the
first air-damping method, filaments are stretched by using a
suction slot (slot stretching). This method is conducted by using
the width of a nozzle or the width of a machine. In the second
air-damping method, filaments are stretched through a nozzle or a
suction gun. The filaments formed through the above methods are
collected to form a web on a screen (wire) or a hole forming belt.
Subsequently, the web passes through a compression roll and then
passes between heating calendar rolls, and the web is bounded in a
portion where an embossment portion on one roll includes about 10%
to 40% of the area of the web, thereby forming a nonwoven
fabric.
[0053] Specific conditions for producing the fibrous nonwoven
fabric by the above-described spunbond method are hereunder
explained.
[Production Condition 1]
[0054] In the case of producing the fibrous nonwoven fabric of the
present invention by a spunbonded nonwoven fabric molding machine
using an ejector system, when the fibrous nonwoven fabric is
produced by using the above-described resin composition (C) by the
spunbond method under the following conditions, reducing the fiber
diameter can be achieved to an extent that the fiber diameter is
1.0 denier or less.
(1) Resin temperature: 200.degree. C. to 270.degree. C. (2)
Discharge amount per hole: 0.1 g/min to 0.5 g/min (3) Ejector
pressure: 1.0 kg/cm.sup.2 to 4.0 kg/cm.sup.2 (4) Suction pressure:
600 rpm to 900 rpm (5) Calendar temperature: 100.degree. C. to
150.degree. C. (6) Nip pressure: 40 kg/cm
[0055] As for the above-described production condition 1, in
reducing fiber diameter of fibers, in particular, it is preferred
to set it to conditions under which relations represented by the
following expressions (1-1) to (1-4) are held between the discharge
amount per hole ([T] g/min) and the ejector pressure ([E]
kg/cm.sup.2).
[T]/[E].ltoreq.0.25 (1-1)
[T]/[E].ltoreq.0.2 (1-2)
[T]/[E].ltoreq.0.13 (1-3)
[T]/[E].ltoreq.0.1 (1-4)
[0056] When the [T]/[E] is 0.25 or less, the fibers of the
resulting fibrous nonwoven fabric are likely to become a fine fiber
with 1.3 deniers or less; when it is 0.2 or less, the
above-described fibers are likely to become a fine fiber with 1.0
denier or less; when it is 0.13 or less, the above-described fibers
are likely to become a fine fiber with 0.8 deniers or less; and
when it is 0.1 or less, the above-described fibers are likely to
become a fine fiber with 0.6 deniers or less.
[Production Condition 2]
[0057] In the case of producing the fibrous nonwoven fabric of the
present invention by a spunbonded nonwoven fabric molding machine
using a cabin system, when the fibrous nonwoven fabric is produced
by using the above-described resin composition (C) by the spunbond
method under the following conditions, reducing the fiber diameter
can be achieved to an extent that the fiber diameter is 1.0 denier
or less.
(1) Resin temperature: 200.degree. C. to 270.degree. C. (2)
Discharge amount per hole: 0.3 g/min to 0.6 g/min (3) Cabin
pressure: 4,500 Pa to 8,000 Pa (4) Calendar temperature:
100.degree. C. to 150.degree. C. (5) Nip pressure: 100 N/mm
[0058] As for the above-described production condition 2, in
reducing fiber diameter of fibers, in particular, it is preferred
to set it to conditions under which relations represented by the
following expressions (2-1) to (2-3) are held between the discharge
amount per hole ([T] g/min) and the cabin pressure ([C] Pa).
[T]/[C].times.1,000.ltoreq.0.09 (2-1)
[T]/[C].times.1,000.ltoreq.0.06 (2-2)
[T]/[C].times.1,000.ltoreq.0.05 (2-3)
[0059] When the "[T]/[C].times.1,000" is 0.09 or less, the fibers
of the resulting fibrous nonwoven fabric are likely to become a
fine fiber with 1.3 deniers or less; when it is 0.06 or less, the
above-described fibers are likely to become a fine fiber with 1.0
denier or less; and when it is 0.05 or less, the above-described
fibers are likely to become a fine fiber with 0.9 deniers or
less.
[0060] In producing the fibrous nonwoven fabric of the first
invention, in the case of using an external release agent, the
external release agent is sprayed onto the above-described moving
collecting surface. In the case where the resin composition (C)
contains the internal release agent, though the external release
agent may not be sprayed onto the above-described moving collecting
surface, it may also be used in combination with the internal
release agent from the standpoint of obtaining good release
properties.
[0061] Specific examples of the above-described external release
agent include fluorine-based release agents and silicone-based
release agents. Examples of the fluorine-based release agent
include DAIFREE, manufactured by Daikin Industries, Ltd. and
FRELEASE, manufactured by Neos Company Limited. Examples of the
silicone-based release agent include SPRAY 200, manufactured by Dow
Corning Toray Silicone Co., Ltd.; KF96SP, manufactured by Shin-Etsu
Chemical Co., Ltd.; EPOLEASE 96, manufactured by Pelnox, Ltd.;
KURE-1046, manufactured by Kure Engineering Ltd.; and the like.
These can be used solely or in combination of two or more kinds
thereof. In the first invention, among these external release
agents, silicone-based release agents are preferred.
[0062] Examples of a method of spraying the external release agent
onto the above-described moving collecting surface include a method
by spraying and the like.
[0063] The following fiber products can be given as examples of a
fiber product using the fibrous non-woven fabric of the first
invention. That is, a member for a disposable diaper, a stretchable
member for a diaper cover, a stretchable member for a sanitary
product, a stretchable member for a hygienic product, a stretchable
tape, an adhesive bandage, a stretchable member for clothing, an
insulating material for clothing, a heat insulating material for
clothing, a protective suit, a hat, a mask, a glove, a supporter, a
stretchable bandage, a base fabric for a fomentation, a non-slip
base fabric, a vibration absorber, a finger cot, an air filter for
a clean room, an electret filter subjected to electret processing,
a separator, a heat insulator, a coffee bag, a food packaging
material, a ceiling skin material for an automobile, an acoustic
insulating material, a cushioning material, a speaker dust-proof
material, an air cleaner material, an insulator skin, a backing
material, an adhesive non-woven fabric sheet, various members for
automobiles such as a door trim, various cleaning materials such as
a cleaning material for a copying machine, the facing and backing
of a carpet, an agricultural beaming, a timber drain, members for
shoes such as a sport shoe skin, a member for a bag, an industrial
sealing material, a wiping material, a sheet, and the like can be
given. The fibrous non-woven fabric of the present invention is
preferably used particularly in a hygienic material such as a paper
diaper.
<Second Invention>
[0064] A spunbonded nonwoven fabric according to a second invention
is constituted of fibers having a fineness of 0.2 to 1.0 denier
(preferably 0.2 to 0.8 deniers, more preferably 0.2 to 0.6 deniers,
and still more preferably 0.3 to 0.6 deniers).
[0065] Details of the spunbond woven fabric according to the second
invention are the same as those in the fibrous nonwoven fabric
according to the first invention, except that the spunbond woven
fabric is not limited to one composed of the resin composition (C)
containing the high-crystalline polyolefin (A) and the
low-crystalline polyolefin (B) as described above. The spunbond
woven fabric according to the second invention can be suitably
produced by the spunbond method (production condition 1) using the
above-described ejector system.
EXAMPLES
[0066] The following Examples are merely explained for the purpose
of exemplification and are non-limitative examples.
Example 1
Preparation of Resin Composition
[0067] To a resin mixture composed of 10 parts by mass of a
low-crystalline polypropylene ("L-MODU (a registered trademark)
S901", manufactured by Idemitsu Kosan Co., Ltd., MFR: 50 g/10 min,
melting point: 70.degree. C.) and 90 parts by mass of a
high-crystalline polypropylene A ("NOVATEC SA-03", manufactured by
Japan Polypropylene Corporation, MFR: 30 g/10 min, melting point:
160.degree. C.), erucic acid amide was added in an amount of 2,000
ppm on the basis of the resin mixture, thereby preparing a resin
composition.
[0068] Physical properties of the low-crystalline polypropylene and
the high-crystalline polypropylene A as described above were
measured by the following measuring methods. Results are shown in
Table 1.
[Initial Elastic Modulus]
[0069] The polypropylene was subjected to press molding to
fabricate a test piece, the initial elastic modulus of which was
then measured by a tensile test in conformity with JIS K-7113.
[0070] Thickness of test piece (No. 2 dumbbell): 1 mm [0071]
Cross-head speed: 50 mm/min [0072] Loadcell: 100 kg
[Half-Crystallization Time]
[0073] A half-crystallization time measured by the following method
using FLASH DSC (manufactured by Mettler-Toledo International Inc.)
was used.
(1) The sample is melted by heating at 230.degree. C. for 2 minutes
and then cooled to 25.degree. C. at a rate of 2,000.degree. C./sec,
and a time change of heating value in an isothermal crystallization
process at 25.degree. C. is measured. (2) When an integrated value
of heating value from start of the isothermal crystallization to
completion of the crystallization is defined as 100%, a time from
start of the isothermal crystallization until the integrated value
of heating value reaches 50% was defined as the
half-crystallization time.
[Melt Flow Rate (MFR)]
[0074] The melt flow rate was measured under conditions at a
temperature of 230.degree. C. and at a load of 21.18 N in
conformity with JIS K7210.
[Melting Point]
[0075] The melting point (Tm-D) was determined from a peak top of a
peak observed on the highest temperature side of a melt endothermic
curve obtained by maintaining 10 mg of the sample at -10.degree. C.
for 5 minutes and then increasing the temperature at a rate of
10.degree. C./min by using a differential scanning calorimeter
(DSC-7, manufactured PerkinElmer Inc.) under a nitrogen
atmosphere.
[Measurement of Weight Average Molecular Weight (Mw) and Molecular
Weight Distribution (Mw/Mn)]
[0076] The weight average molecular weight (Mw) and the molecular
weight distribution (Mw/Mn) were determined by a 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.
<GPC Measuring Device>
[0077] Column: TOSO GMHHR-H(S)HT
[0078] Detector: RI detector for liquid chromatography, WATERS
150C
<Measurement Conditions>
[0079] Solvent: 1,2,4-trichlorobezene
[0080] Measurement temperature: 145.degree. C.
[0081] Flow rate: 1.0 mL/min
[0082] Sample concentration: 2.2 mg/mL
[0083] Injection amount: 160 .mu.L
[0084] Calibration curve: Universal Calibration
[0085] Analysis program: HT-GPC (ver. 1.0)
[NMR Measurement]
[0086] The .sup.13C-NMR spectrum was measured with the following
device under the following conditions. The peak assignment followed
to the method proposed by A. Zambelli, et al., "Macromolecules, 8,
687 (1975)".
[0087] Device: .sup.13C-NMR device, JNM-EX400 series, manufactured
by JEOL, Ltd.
[0088] Method: Proton complete decoupling method
[0089] Concentration: 220 mg/mL
[0090] Solvent: Mixed solvent of 1,2,4-trichlorobenzene and
deuterated benzene in a ratio of 90/10 (volume ratio)
[0091] Temperature: 130.degree. C.
[0092] Pulse width: 45.degree.
[0093] Pulse repetition time: 4 seconds
[0094] Accumulation: 10,000 times
<Calculating Expressions>
[0095] M=m/S.times.100
R=.gamma./S.times.100
S=P.beta..beta.+P.alpha..beta.+P.alpha..gamma.
[0096] S: Signal intensity of carbon atoms in side chain methyl of
all the propylene units
[0097] P.beta..beta.: 19.8 to 22.5 ppm
[0098] P.alpha..beta.: 18.0 to 17.5 ppm
[0099] P.alpha..gamma.: 17.5 to 17.1 ppm
[0100] Racemic pentad chain, 20.7 to 20.3 ppm
[0101] m: Mesopentad chain, 21.7 to 22.5 ppm
[0102] The mesopentad fraction [mmmm], the racemic pentad fraction
[rrrr], and the racemic-meso-racemic-meso pentad fraction [rmrm]
are measured in conformity with the method proposed by A. Zambelli,
et al., "Macromolecules, 6, 925 (1973)" and are a meso fraction, a
racemic fraction, and a racemic-meso-racemic-meso fraction,
respectively in the pentad units of the polypropylene molecular
chain that are measured based on a signal of the methyl group in
the .sup.13C-NMR spectrum. As the mesopentad fraction [mmmm]
increases, the stereoregularity increases. In addition, the triad
fractions [mm], [rr], and [mr] were also calculated by the
above-described method.
[0103] In addition, with respect to the above-described resin
composition, the half-crystallization time was also measured by the
above-described measuring method. Furthermore, a value obtained by
dividing the half-crystallization time of the resin composition by
the half-crystallization time of the high-crystalline polypropylene
was defined as a relative crystallization time ratio. Results are
shown in Table 2.
(Production of Fibrous Nonwoven Fabric)
[0104] The above-described resin composition was melt extruded at a
resin temperature of 250.degree. C. by using a single-screw
extruder with a gear pump, and the molten resin was spun by
discharging from a nozzle having a nozzle diameter of 0.3 mm (hole
number: 841 holes) at a rate of 0.1 g/min in terms of a discharge
amount per hole. Fibers obtained by spinning were sucked under the
nozzle by an ejector at a pressure of 1.0 kg/cm.sup.2 while cooling
with air and laminated on a net surface moving at a line speed of
11 m/min. A fiber bundle laminated on the net surface was embossed
at a nip pressure of 40 N/mm by using calendar rolls heated at
140.degree. C. and then wound up by a wind-up roll. Here, [T]/[E]
obtained from a relation between the discharge amount per hole and
the ejector pressure was 0.1.
[0105] The resulting fibrous nonwoven fabric was measured for basis
weight, fineness, breaking strength, breaking strain and static
friction coefficient of the nonwoven fabric, and also subjected to
cantilever measurement in the following measuring methods.
Measurement results are shown in Table 2.
[Basis Weight]
[0106] The weight of the resulting nonwoven fabric of 5 cm.times.5
cm was measured, thereby measuring the basis weight
(g/m.sup.2).
[Fineness]
[0107] The fibers in the nonwoven fabric were observed with a
polarizing microscope, an average value (d) of diameter of randomly
selected five fibers was measured, and the fineness of the nonwoven
fabric sample was calculated from the following expression [1] by
using a density of the resin (p=900,000 g/m.sup.3).
Fineness(denier)=p.times.n.times.(d/2).sup.2.times.9,000 [1]
[Breaking Strength-Breaking Strain]
[0108] From a test piece (200 mm in length.times.50 mm in width) of
the resulting nonwoven fabric, sampling was conducted in the
machine direction (MD) and the cross-machine direction (CD)
vertical to the machine direction. Using a tensile tester
(AUTOGRAPH AG-1, manufactured by Shimadzu Corporation), the test
piece was set at an initial length L0 of 100 mm, stretched at a
tensile speed of 300 mm/min, and measured for a stain and a load in
the stretching process, and values of the load and the strain at
the moment when the nonwoven fabric was broken were defined as
breaking strength and breaking strain, respectively.
[Static Friction Coefficient]
[0109] From test pieces (220 mm in length.times.100 mm in width and
220 mm in length.times.70 mm in width) of the resulting nonwoven
fabric, sampling was conducted in the machine direction (MD) and
the cross-machine direction (CD) vertical to the machine direction.
Two sheets of the nonwoven fabrics were overlaid on a seating of a
static friction coefficient measuring device (friction measuring
device AN type, manufactured by Toyo Seiki Kogyo Co., Ltd.); a
weight of 1,000 g was placed thereon; the seating was inclined at a
rate of 2.7 degrees/min; an angle when the nonwoven fabrics slipped
10 mm was measured; and from the weight (1,000 g) of the placed
weight and the angle when the nonwoven fabrics slipped 10 mm, the
static friction coefficient was calculated. The smaller friction
coefficient shows that the spunbonded nonwoven fabric has good hand
touch feeling and texture.
[Cantilever Test]
[0110] A test piece of 100 mm in length.times.100 mm in width was
fabricated from the resulting nonwoven fabric, and the cantilever
test was conducted by using a cantilever tester having a slope
having an incline angle of 45.degree. in one end of a seating
thereof. The test piece was slipped on the seating at a fixed speed
in the slope direction, and a movement distance of the nonwoven
fabric at the moment when the test piece was bent and one end
thereof came into contact with the slope was measured. The
measurement was conducted in both of the machine direction (MD) and
the cross-machine direction (CD) vertical to the machine
direction.
Example 2
[0111] A nonwoven fabric was molded and evaluated in the same
manners as those in Example 1, except that in Example 1, the
discharge amount per hole was changed to 0.2 g/min, the ejector
pressure was changed to 4.0 kg/cm.sup.2, and the line speed was
changed to 24 m/min. Results are shown in Table 2. At that time,
[T]/[E] obtained from a relation between the discharge amount per
hole and the ejector pressure was 0.05.
Example 3
[0112] A nonwoven fabric was molded and evaluated in the same
manners as those in Example 1, except that in Example 1, the
discharge amount per hole was changed to 0.3 g/min, the ejector
pressure was changed to 2.0 kg/cm.sup.2, and the line speed was
changed to 35 m/min. Results are shown in Table 2. At that time,
[T]/[E] obtained from a relation between the discharge amount per
hole and the ejector pressure was 0.15.
Comparative Example 1
[0113] A nonwoven fabric was molded and evaluated in the same
manners as those in Example 1, except that in Example 1, the
addition amount of the low-crystalline polypropylene was changed to
1% by mass, the discharge amount per hole was changed to 0.5 g/min,
the ejector pressure was changed to 2.0 kg/cm.sup.2, and the line
speed was changed to 54 m/min. Results are shown in Table 2. At
that time, [T]/[E] obtained from a relation between the discharge
amount per hole and the ejector pressure was 0.25.
Comparative Example 2
[0114] A nonwoven fabric was molded and evaluated in the same
manners as those in Example 1, except that in Example 1, the
low-crystalline polypropylene was not added, the discharge amount
per hole was changed to 0.5 g/min, the ejector pressure was changed
to 2.0 kg/cm.sup.2, and the line speed was changed to 54 m/min.
Results are shown in Table 2. At that time, [T]/[E] obtained from a
relation between the discharge amount per hole and the ejector
pressure was 0.25.
TABLE-US-00001 TABLE 1 Low- High- High- High- crystalline
crystalline crystalline crystalline poly- poly- poly- poly-
propylene propylene A propylene B propylene C Initial elastic 125
1,650 1,550 1,450 modulus (MPa) Half- 540 0.066 0.066 0.066
crystallization time (sec) MFR (g/10 min) 50 30 36 33 Melting point
70 160 161 163 (.degree. C.)
TABLE-US-00002 TABLE 2 Comparative Examples Examples 1 2 3 1 2
Composition High-crystalline PP-A 90 90 90 99 100 of resin (parts
by mass) Low-crystalline PP (parts by mass) 10 10 10 1 0 Erucic
acid amide (ppm) 2000 2000 2000 0 0 Properties of
Half-crystallization time (t.sub.c, sec) 0.094 0.094 0.094 0.0693
0.066 resin (t.sub.c/t.sub.a) 1.42 1.42 1.42 1.05 1.00 Molding
Resin temperature (.degree. C.) 250 250 250 250 250 conditions
Discharge amount per hole (g/min) 0.1 0.2 0.3 0.5 0.5 Ejector
pressure (kg/cm.sup.2) 1 4 2 2 2 [T]/[E] 0.1 0.05 0.15 0.25 0.25
Line speed (m/min) 11 24 35 54 54 Calendar temperature (.degree.
C.) 140 135 140 140 140 Nip pressure (N/mm) 40 40 40 40 40
Performance Basis weight (g/m.sup.2) 13 13 13 13 13 of nonwoven
Fineness (denier) 0.4 0.5 0.9 1.6 1.7 fabric Breaking strength (N/5
cm) MD 51 84 50 46 44 CD 17 22 19 20 19 Breaking strain (%) MD 44
70 50 55 51 CD 58 77 64 67 64 Static friction coefficient MD 0.34
0.37 0.29 0.46 0.46 CD 0.44 0.46 0.35 0.57 0.56 Cantilever test
(mm) MD 52 48 56 50 51 CD 26 30 45 32 33
Example 4
Preparation of Resin Composition
[0115] To a resin mixture composed of 10 parts by mass of a
low-crystalline polypropylene ("L-MODU (a registered trademark)
S901", manufactured by Idemitsu Kosan Co., Ltd., MFR: 50 g/10 min,
melting point: 70.degree. C.) and 90 parts by mass of a
high-crystalline polypropylene B ("PP3155", manufactured by
ExxonMobil, MFR: 36 g/10 min, melting point: 161.degree. C.),
erucic acid amide was added in an amount of 2,000 ppm on the basis
of the resin mixture, thereby preparing a resin composition.
[0116] Physical properties of the above-described high-crystalline
polypropylene B were measured by the above-described measuring
methods. Results are shown in Table 1.
[0117] In addition, with respect to the above-described resin
composition, its half-crystallization time was measured by the
above-described measuring method. Furthermore, a value obtained by
dividing the half-crystallization time of the resin composition by
the half-crystallization time of the high-crystalline polypropylene
was defined as a relative crystallization time ratio. Results are
shown in Table 3.
[0118] The above-described resin composition was melt extruded at a
resin temperature of 250.degree. C. by using a single-screw
extruder with a gear pump, and the molten resin was spun by
discharging from a nozzle having a nozzle diameter of 0.6 mm (hole
number: 5,800 holes/m) at a rate of 0.47 g/min in terms of a
discharge amount per hole. Fibers obtained by spinning were sucked
under the nozzle by a cooling air duct at a cabin pressure of 8,000
Pa while cooling with air and laminated on a net surface moving at
a line speed of 180 m/min. A fiber bundle laminated on the net
surface was embossed at a nip pressure of 100 N/mm by using
calendar rolls heated at 140.degree. C. and then wound up by a
wind-up roll. Here, "[T]/[C].times.1,000" obtained from a relation
between the discharge amount per hole and the cabin pressure was
0.06.
[0119] The resulting nonwoven fabric was measured for basis weight,
fineness, breaking strength, breaking strain and static friction
coefficient of the nonwoven fabric, and also subjected to
cantilever measurement in the above-described measuring methods.
Measurement results are shown in Table 3.
Example 5
[0120] A nonwoven fabric was molded and evaluated in the same
manners as those in Example 4, except that in Example 4, the cabin
pressure was changed to 6,500 Pa. Results are shown in Table 3. At
that time, [T]/[C].times.1,000 obtained from a relation between the
discharge amount per hole and the cabin pressure was 0.07.
Example 6
[0121] A nonwoven fabric was molded and evaluated in the same
manners as those in Example 4, except that in Example 4, 15 parts
by mass of the low-crystalline polypropylene and 85 parts by mass
of the high-crystalline polypropylene B were mixed, and the erucic
acid amide was not added, thereby preparing a resin composition;
the cabin pressure was changed to 7,500 Pa; and the line speed was
changed to 150 m/min. Results are shown in Table 3. At that time,
[T]/[C].times.1,000 obtained from a relation between the discharge
amount per hole and the cabin pressure was 0.05.
Example 7
[0122] A nonwoven fabric was molded and evaluated in the same
manners as those in Example 6, except that in Example 6, the cabin
pressure was changed to 6,000 Pa. Results are shown in Table 3. At
that time, [T]/[C].times.1,000 obtained from a relation between the
discharge amount per hole and the cabin pressure was 0.06.
Example 8
Preparation of Resin Composition
[0123] To a resin mixture composed of 5 parts by mass of a
low-crystalline polypropylene ("L-MODU (a registered trademark)
S901", manufactured by Idemitsu Kosan Co., Ltd., MFR: 50 g/10 min,
melting point: 70.degree. C.) and 95 parts by mass of a
high-crystalline polypropylene B ("PP3155", manufactured by Exxon
Mobil Corporation, MFR: 36 g/10 min, melting point: 161.degree.
C.), erucic acid amide was added in an amount of 2,000 ppm on the
basis of the resin mixture, thereby preparing a resin
composition.
[0124] In addition, with respect to the above-described resin
composition, its half-crystallization time was measured by the
above-described measuring method. Furthermore, a value obtained by
dividing the half-crystallization time of the resin composition by
the half-crystallization time of the high-crystalline polypropylene
was defined as a relative crystallization time ratio. Results are
shown in Table 3.
[0125] The above-described resin composition was melt extruded at a
resin temperature of 245.degree. C. by using a single-screw
extruder with a gear pump, and the molten resin was spun by
discharging from a nozzle having a nozzle diameter of 0.6 mm (hole
number: 5,800 holes/m) at a rate of 0.40 g/min in terms of a
discharge amount per hole. Fibers obtained by spinning were sucked
under the nozzle by a cooling air duct at a cabin pressure of 5,500
Pa while cooling with air and laminated on a net surface moving at
a line speed of 530 m/min. A fiber bundle laminated on the net
surface was embossed at a nip pressure of 100 N/mm by using
calendar rolls heated at 146.degree. C. and then wound up by a
wind-up roll. Here, "[T]/[C].times.1,000" obtained from a relation
between the discharge amount per hole and the cabin pressure was
0.07.
[0126] The resulting nonwoven fabric was measured for basis weight,
fineness, breaking strength, breaking strain and static friction
coefficient of the nonwoven fabric, and also subjected to
cantilever measurement in the above-described measuring methods.
Measurement results are shown in Table 3.
Example 9
Preparation of Resin Composition
[0127] To a resin mixture composed of 20 parts by mass of a
low-crystalline polypropylene ("L-MODU (a registered trademark)
S901", manufactured by Idemitsu Kosan Co., Ltd., MFR: 50 g/10 min,
melting point: 70.degree. C.) and 80 parts by mass of a
high-crystalline polypropylene C ("MOPLEN HP561S", manufactured by
LyondellBasell, MFR: 33 g/10 min, melting point: 163.degree. C.),
erucic acid amide was added in an amount of 2,000 ppm on the basis
of the resin mixture, thereby preparing a resin composition.
[0128] Physical properties of the above-described high-crystalline
polypropylene C were measured by the above-described measuring
methods. Results are shown in Table 1.
[0129] In addition, with respect to the above-described resin
composition, its half-crystallization time was measured by the
above-described measuring method. Furthermore, a value obtained by
dividing the half-crystallization time of the resin composition by
the half-crystallization time of the high-crystalline polypropylene
was defined as a relative crystallization time ratio. Results are
shown in Table 3.
[0130] The above-described resin composition was melt extruded at a
resin temperature of 240.degree. C. by using a single-screw
extruder with a gear pump, and the molten resin was spun by
discharging from a nozzle having a nozzle diameter of 0.6 mm (hole
number: 5,800 holes/m) at a rate of 0.57 g/min in terms of a
discharge amount per hole. Fibers obtained by spinning were sucked
under the nozzle by a cooling air duct at a cabin pressure of 6,000
Pa while cooling with air and laminated on a net surface moving at
a line speed of 214 m/min. A fiber bundle laminated on the net
surface was embossed at a nip pressure of 70 N/mm by using calendar
rolls heated at 136.degree. C. and then wound up by a wind-up roll.
Here, "[T]/[C].times.1,000" obtained from a relation between the
discharge amount per hole and the cabin pressure was 0.10.
[0131] The resulting nonwoven fabric was measured for basis weight,
fineness, breaking strength, breaking strain and static friction
coefficient of the nonwoven fabric, and also subjected to
cantilever measurement in the above-described measuring methods.
Measurement results are shown in Table 3.
Comparative Example 3
[0132] A nonwoven fabric was molded and evaluated in the same
manners as those in Example 4, except that in Example 4, 1 part by
mass of the low-crystalline polypropylene and 99 parts by mass of
the high-crystalline polypropylene B were mixed, and the erucic
acid amide was not added, thereby preparing a resin composition;
the cabin pressure was changed to 4,500 Pa; and the line speed was
changed to 220 m/min. Results are shown in Table 3. At that time,
[T]/[C].times.1,000 obtained from a relation between the discharge
amount per hole and the cabin pressure was 0.13.
Comparative Example 4
[0133] A nonwoven fabric was molded and evaluated in the same
manners as those in Example 4, except that in Example 4, only the
high-crystalline polypropylene B was added as the raw material
resin without adding the low-crystalline polypropylene and the
erucic acid amide; the cabin pressure was changed to 4,500 Pa; and
the line speed was changed to 220 m/min. Results are shown in Table
3. At that time, [T]/[C].times.1,000 obtained from a relation
between the discharge amount per hole and the cabin pressure was
0.14.
Comparative Example 5
[0134] A resin composition was prepared by mixing 25 parts by mass
of a low-crystalline polypropylene ("L-MODU (a registered
trademark) S901", manufactured by Idemitsu Kosan Co., Ltd., MFR: 50
g/10 min, melting point: 70.degree. C.) and 75 parts by mass of the
high-crystalline polypropylene C ("MOPLEN HP561S", manufactured by
LyondellBasell, MFR: 33 g/10 min, melting point: 163.degree. C.)
without adding erucic acid amide.
[0135] In addition, with respect to the above-described resin
composition, its half-crystallization time was measured by the
above-described measuring method. Furthermore, a value obtained by
dividing the half-crystallization time of the resin composition by
the half-crystallization time of the high-crystalline polypropylene
was defined as a relative crystallization time ratio. Results are
shown in Table 3.
[0136] The above-described resin composition was melt extruded at a
resin temperature of 236.degree. C. by using a single-screw
extruder with a gear pump, and the molten resin was spun by
discharging from a nozzle having a nozzle diameter of 0.6 mm (hole
number: 5,800 holes/m) at a rate of 0.57 g/min in terms of a
discharge amount per hole. Fibers obtained by spinning were sucked
under the nozzle by a cooling air duct at a cabin pressure of 5,500
Pa while cooling with air and laminated on a net surface moving at
a line speed of 215 m/min. A fiber bundle laminated on the net
surface was embossed at a nip pressure of 90 N/mm by using calendar
rolls heated at 134.degree. C. and then wound up by a wind-up roll.
Here, "[T]/[C].times.1,000" obtained from a relation between the
discharge amount per hole and the cabin pressure was 0.10.
[0137] The resulting nonwoven fabric was measured for basis weight,
fineness, breaking strength, breaking strain and static friction
coefficient of the nonwoven fabric, and also subjected to
cantilever measurement in the above-described measuring methods.
Measurement results are shown in Table 3.
TABLE-US-00003 TABLE 3 Examples Comparative Examples 4 5 6 7 8 9 3
4 5 Composition High-crystalline PP-B 90 90 85 85 95 0 99 100 0 of
resin (parts by mass) High-crystalline PP-C 0 0 0 0 0 80 0 0 75
(parts by mass) Low-crystalline PP 10 10 15 15 5 20 1 0 25 (parts
by mass) Erucic acid amide (ppm) 2000 2000 0 0 2000 2000 0 0 0
Properties Half-crystallization time (t.sub.c, sec) 0.094 0.094
0.11 0.11 0.081 0.127 0.0693 0.066 0.141 of resin (t.sub.c/t.sub.a)
1.42 1.42 1.67 1.67 1.21 1.91 1.05 1.00 2.12 Molding Resin
temperature (.degree. C.) 250 250 250 250 245 240 250 250 236
conditions Discharge amount per hole 0.47 0.47 0.39 0.36 0.40 0.57
0.57 0.57 0.57 (g/min) Cabin pressure (MPa) 8000 6500 7500 6000
5500 6000 4500 4000 5500 [T]/[C] .times. 1,000 0.06 0.07 0.05 0.06
0.07 0.10 0.13 0.14 0.10 Line speed (m/min) 180 180 150 140 530 214
220 220 215 Calendar temperature (.degree. C.) 140 140 140 140 146
136 140 140 134 Nip pressure (N/mm) 100 100 100 100 100 70 100 100
90 Performance Basis weight (g/m.sup.2) 15 15 15 15 13 15 15 15 15
of nonwoven Fineness (denier) 0.92 1.1 0.87 0.97 1.1 1.4 1.7 1.8
1.5 fabric Breaking strength MD 45 45 50 49 36 22 35 32 38 (N/5 cm)
CD 21 20 25 31 18 15 16 15 24 Breaking strain (%) MD 67 72 67 63 64
47 50 43 54 CD 87 79 86 79 80 59 65 50 72 Static friction
coefficient MD 0.26 0.25 0.57 0.57 0.27 0.25 0.55 0.55 0.61 CD 0.3
0.3 0.63 0.63 0.28 0.29 0.6 0.58 0.72 Cantilever test (mm) MD 38 39
38 38 32 35 50 47 40 CD 24 23 24 24 22 24 35 33 30
INDUSTRIAL APPLICABILITY
[0138] The fibrous nonwoven fabric of the present invention is
extremely small in fiber diameter and good in hand touch feeling
and is especially preferably used for hygienic materials, such as a
paper diaper, etc.
* * * * *