U.S. patent application number 13/982640 was filed with the patent office on 2013-12-05 for nonwoven fabric and textile product.
This patent application is currently assigned to IDEMITSU KOSAN CO., LTD.. The applicant listed for this patent is Yohei Koori, Yutaka Minami, Tomoaki Takebe. Invention is credited to Yohei Koori, Yutaka Minami, Tomoaki Takebe.
Application Number | 20130323995 13/982640 |
Document ID | / |
Family ID | 46602777 |
Filed Date | 2013-12-05 |
United States Patent
Application |
20130323995 |
Kind Code |
A1 |
Koori; Yohei ; et
al. |
December 5, 2013 |
NONWOVEN FABRIC AND TEXTILE PRODUCT
Abstract
The nonwoven fabric has excellent secondary fabrication
properties, specially, low temperature heat-sealing properties. The
textile product is formed by using the nonwoven fabric. More
specifically, the nonwoven fabric includes one or more layers,
wherein the nonwoven fabric made of one layer, or at least one
layer of the nonwoven fabric composed of two layers, or at least
one layer of the two outermost layers of the nonwoven fabric of
multi-layer consisting of three or more layers is formed by using a
crystalline resin composition containing 1 to 99% by mass of a low
crystalline olefin polymer satisfying the following expression (a):
.DELTA.H.gtoreq.6.times.(Tm-140.degree. C.) wherein .DELTA.H
represents a melt endotherm, and Tm represents a melting point.
Inventors: |
Koori; Yohei; (Chiba,
JP) ; Takebe; Tomoaki; (Chiba, JP) ; Minami;
Yutaka; (Chiba, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Koori; Yohei
Takebe; Tomoaki
Minami; Yutaka |
Chiba
Chiba
Chiba |
|
JP
JP
JP |
|
|
Assignee: |
IDEMITSU KOSAN CO., LTD.
Tokyo
JP
|
Family ID: |
46602777 |
Appl. No.: |
13/982640 |
Filed: |
January 31, 2012 |
PCT Filed: |
January 31, 2012 |
PCT NO: |
PCT/JP12/52160 |
371 Date: |
July 30, 2013 |
Current U.S.
Class: |
442/364 ;
442/392; 442/414 |
Current CPC
Class: |
Y10T 442/671 20150401;
B32B 5/26 20130101; B32B 2250/05 20130101; B32B 2439/00 20130101;
D04H 3/007 20130101; B32B 5/022 20130101; C08F 110/06 20130101;
Y10T 442/641 20150401; C08F 4/65908 20130101; Y10T 442/696
20150401; D04H 1/4291 20130101; C08F 2500/03 20130101; C08F 2500/15
20130101; B32B 2437/00 20130101; C08F 4/65927 20130101; B32B
2605/00 20130101; C08F 4/65912 20130101 |
Class at
Publication: |
442/364 ;
442/414; 442/392 |
International
Class: |
D04H 3/007 20060101
D04H003/007 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 1, 2011 |
JP |
2011-020151 |
Claims
1. A nonwoven fabric comprising one or more layers, wherein at
least one of the layers comprises a crystalline resin composition
comprising 1 to 99% by mass of a low crystalline olefin polymer
satisfying expression (a): .DELTA.H.gtoreq.6.times.(Tm-140.degree.
C.) (a) wherein .DELTA.H represents a melt endotherm, and Tm
represents a melting point, and if the nonwoven fabric comprises
three or more layers, then at least one of two outermost layers
comprises the crystalline resin composition.
2. A nonwoven fabric comprising one or more layers, wherein at
least one of the layers comprises a core sheath composite fiber
comprising a crystalline resin composition as a sheath component,
wherein an amount of the sheath component is 1 to 99% by mass based
on a total amount of a core component and the sheath component, and
the crystalline resin composition comprises 1 to 99% by mass of a
low crystalline olefin polymer satisfying expression (a):
.DELTA.H.gtoreq.6.times.(Tm-140.degree. C.) (a) wherein .DELTA.H
represents a melt endotherm, and Tm represents a melting point, and
if the nonwoven fabric comprises three or more layers, then an
outermost layer comprises the core-sheath composite fiber.
3. The nonwoven fabric of claim 2, wherein the amount of the sheath
component is 1 to 49% by mass based on the total amount of the core
component and the sheath component.
4. The nonwoven fabric of claim 1, wherein the nonwoven fabric
comprises three or more layers, and a ratio of the outermost layer
comprising the crystalline resin composition to all the layers is 1
to 99% based on areal weight.
5. The nonwoven fabric of claim 4, wherein the ratio of the
outermost layer comprising the crystalline resin composition to all
the layers is 1 to 60% based on areal weight.
6. The nonwoven fabric of claim 1, wherein the crystalline resin
composition comprises 1 to 49% by mass of the low crystalline
olefin polymer.
7. The nonwoven fabric of claim 1, wherein the low crystalline
olefin polymer is a polypropylene polymer.
8. The nonwoven fabric of claim 1, wherein the low crystalline
olefin polymer is a low crystalline polypropylene polymer
satisfying expressions (d) to (i): [mmmm]=20 to 60% by mol (d)
[rrrr]/(1-[mmmm]).ltoreq.0.1 (e) [rmrm]>2.5% by mol (f)
[mm].times.[rr]/[mr].sup.2.ltoreq.2.0 (g) weight-average molecular
weight (Mw)=10,000 to 200,000, and (h) molecular weight
distribution (Mw/Mn)<4, (i) wherein [mmmm] represents a
mesopentad fraction, [rrrr] represents a racemic pentad fraction,
[rmrm] represents a racemic-meso-racemic-meso pentad fraction, [mm]
represents a mesotriad fraction, [rr] represents a racemic triad
fraction, and [mr] represents a meso-racemic triad fraction.
9. A textile product comprising the nonwoven fabric of claim 1.
10. The nonwoven fabric of claim 2, wherein the nonwoven fabric
comprises three or more layers, and a ratio of the outermost layer
comprising the crystalline resin composition to all the layers is 1
to 99% based on areal weight.
11. The nonwoven fabric of claim 10, wherein the ratio of the
outermost layer comprising the crystalline resin composition to all
the layers is 1 to 60% based on areal weight.
12. The nonwoven fabric of claim 2, wherein the crystalline resin
composition comprises 1 to 49% by mass of the low crystalline
olefin polymer.
13. The nonwoven fabric of claim 2, wherein the low crystalline
olefin polymer is a polypropylene polymer.
14. The nonwoven fabric of claim 2, wherein the low crystalline
olefin polymer is a low crystalline polypropylene polymer
satisfying expressions (d) to (i): [mmmm]=20 to 60% by mol (d)
[rrrr]/(1-[mmmm]).ltoreq.0.1 (e) [rmrm]>2.5% by mol (f)
[mm].times.[rr]/[mr].sup.2.ltoreq.2.0 (g) weight-average molecular
weight (Mw)=10,000 to 200,000, and (h) molecular weight
distribution (Mw/Mn)<4, (i) wherein [mmmm] represents a
mesopentad fraction, [rrrr] represents a racemic pentad fraction,
[rmrm] represents a racemic-meso-racemic-meso pentad fraction, [mm]
represents a mesotriad fraction, [rr] represents a racemic triad
fraction, and [mr] represents a meso-racemic triad fraction.
Description
TECHNICAL FIELD
[0001] The present invention relates to a nonwoven fabric with
excellent low temperature heat-sealing properties and a textile
product formed by using the nonwoven fabric.
BACKGROUND ART
[0002] In recent years, polypropylene fibers and nonwoven fabrics
are subjected to various applications including a disposable
diaper, a sanitary product, other hygienic products, a clothing
material, a bandage, and a packaging material. Such fibers and
nonwoven fabrics are often used directly on the skin and are thus
demanded to have suitable elasticity and elastic recovery
properties from the viewpoint of good wear feeling to the body and
of easy body motion after wearing. This has encouraged the various
technological developments of the fibers and nonwoven fabrics. For
example, Patent Literature 1 discloses an elastic nonwoven fabric
with excellent elastic recovery properties and pleasant texture
without stickiness and a textile product formed by using the
elastic nonwoven fabric.
[0003] In addition to such technology developments, a hygienic
product such as a paper diaper is disposable. Therefore, the
production cost is desired to be lowered, by simplifying the
production process. In particular, the secondary processability of
the nonwoven fabric is desired to be improved. One of the indices
of the secondary processability includes the heat-sealing
properties and the laminatability between the nonwoven fabrics or
between a nonwoven fabric and a film. To obtain the necessary
heat-sealing strength at low cost, low temperature heat-sealing
properties are required.
CITATION LIST
Patent Literature
[0004] Patent Literature 1: JP-A-2009-62667
SUMMARY OF THE INVENTION
Technical Problem
[0005] However, conventional high crystalline polypropylene
nonwoven fabrics have a high heat-sealing temperature in order to
obtain the required heat-sealing strength.
[0006] Thus, an objective of the present invention is to provide a
nonwoven fabric with excellent secondary processability,
particularly low temperature heat-sealing properties and a textile
product formed by using the nonwoven fabric.
Solution to Problem
[0007] As the result of their extensive studies on the
above-mentioned problem, the inventors found that using a
crystalline resin composition containing a certain amount of a low
crystalline olefin polymer which has a certain range of melting
point (Tm) and a certain range of melt endotherm (AH) and which
satisfies a specific relationship between the melting point and the
melt endotherm provides a nonwoven fabric with excellent low
temperature heat-sealing properties and a textile product formed by
using the nonwoven fabric. Accordingly, the inventors achieved the
present invention.
[0008] Specifically, the present invention relates to the following
[1] to [9].
[1] A nonwoven fabric including one or more layers, wherein
[0009] the nonwoven fabric made of one layer, or
[0010] at least one layer of the nonwoven fabric composed of two
layers, or
[0011] at least one layer of the two outermost layers of the
nonwoven fabric of multi-layer consisting of three or more
layers
is formed by using a crystalline resin composition containing 1 to
99% by mass of a low crystalline olefin polymer satisfying the
following expression (a):
.DELTA.H.gtoreq.6.times.(Tm-140.degree. C.) (a)
wherein .DELTA.H represents a melt endotherm, and Tm represents a
melting point. [2] A nonwoven fabric including one or more layers,
wherein
[0012] a fiber forming the nonwoven fabric made of one layer,
or
[0013] a fiber forming at least one layer in the nonwoven fabric
composed of two layers, or
[0014] a fiber forming the outermost layer of the nonwoven fabric
of the multi-layer consisting of three or more layers
each are a core-sheath composite fiber containing a crystalline
resin composition as the sheath component, the ratio of the sheath
component is 1 to 99% by mass based on the total amount of the core
component and the sheath component, and the crystalline resin
composition contains 1 to 99% by mass of a low crystalline olefin
polymer satisfying the following expression (a):
.DELTA.H.gtoreq.6.times.(Tm-140.degree. C.) (a)
wherein .DELTA.H represents a melt endotherm, and Tm represents a
melting point. [3] The nonwoven fabric according to [2], wherein
the ratio of the sheath component is 1 to 49% by mass based on the
total amount of the core component and the sheath component. [4]
The nonwoven fabric according to any one of [1] to [3], wherein in
the nonwoven fabric having three or more layers, the ratio of the
outermost layer formed by using the crystalline resin composition
to all the layers is 1 to 99% based on areal weight. [5] The
nonwoven fabric according to [4], wherein the ratio of the
outermost layer formed by using the crystalline resin composition
to all the layers is 1 to 60% based on areal weight. [6] The
nonwoven fabric according to any one of [1] to [5], wherein the
crystalline resin composition contains 1 to 49% by mass of a low
crystalline olefin polymer satisfying the expression (a). [7] The
nonwoven fabric according to any one of [1] to [6], wherein the low
crystalline olefin polymer is a polypropylene polymer. [8] The
nonwoven fabric according to any one of [1] to [7], wherein the low
crystalline olefin polymer is a low crystalline polypropylene
polymer satisfying the following expressions (d) to (i):
[mmmm]=20 to 60% by mol (d)
[rrrr]/(1-[mmmm]).ltoreq.0.1 (e)
[rmrm]>2.5% by mol (f)
[mm].times.[rr]/[mr].sup.2.ltoreq.2.0 (g)
Weight-average molecular weight (Mw)=10,000 to 200,000, and (h)
Molecular weight distribution (Mw/Mn)<4, (i)
wherein [mmmm] represents a mesopentad fraction, [rrrr] represents
a racemic pentad fraction, [rmrm] represents a
racemic-meso-racemic-meso pentad fraction, [mm] represents a
mesotriad fraction, [rr] represents a racemic triad fraction, and
[mr] represents a meso-racemic triad fraction. [9] A textile
product formed by using the nonwoven fabric according to any one of
[1] to [8].
Advantageous Effects of the Invention
[0015] The nonwoven fabric of the present invention has
particularly excellent low temperature heat-sealing properties (for
example, heat-sealing strength at 160 to 180.degree. C.) so as to
stably provide various inexpensive textile products with excellent
secondary processability.
MODE FOR CARRYING OUT THE INVENTION
[0016] The nonwoven fabric of the present invention is produced by
using a crystalline resin composition containing a certain amount
of a low crystalline olefin polymer. In the present invention, the
low crystalline olefin polymer has moderately disturbed
stereoregularity, which specifically means an olefin polymer
satisfying the following expression (a). On the other hand, an
olefin polymer not satisfying the expression (a) is sometimes
referred to as a high crystalline olefin polymer. For example, when
the olefin polymer is a polypropylene, the high crystalline olefin
polymer is a high crystalline polypropylene.
.DELTA.H.gtoreq.6.times.(Tm-140.degree. C.) (a)
In the expression, .DELTA.H represents a melt endotherm, and Tm
represents a melting point. The expression (a) shows that the melt
endotherm is high for a melting point. An olefin polymer obtained
by the below-mentioned process of producing a low crystalline
olefin polymer satisfies the expression (a). However, an olefin
polymer produced by using a conventional Ziegler-Natta catalyst
with different catalytic sites does typically not satisfy the
expression (a).
[0017] The crystalline resin composition used in the present
invention is a composition containing a low crystalline olefin
polymer, as described above.
[0018] The low crystalline olefin polymer preferably satisfies the
following conditions (b) or (c), more preferably (b) and (c).
The melting point (Tm) is 0.degree. C. or more and less than
120.degree. C. (b)
The melt endotherm (.DELTA.H) is from 1 to 100 J/g. (c)
Low Crystalline Olefin Polymer:
[0019] The low crystalline olefin polymer used in the present
invention is preferably an olefin polymer generated by polymerizing
one or more kinds of monomers selected from ethylene and
.alpha.-olefins with 3 to 28 carbon atoms, particularly preferably
an olefin polymer generated by polymerizing one or more kinds of
monomers selected from .alpha.-olefins with 3 to 28 carbon
atoms.
[0020] The .alpha.-olefins with 3 to 28 carbon atoms include, for
example, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene,
1-hexene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene,
1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene,
1-octadecene, 1-nonadecene, and 1-icosene. The .alpha.-olefin has
preferably 3 to 16 carbon atoms, more preferably 3 to 10 carbon
atoms, further more preferably 3 to 6 carbon atoms, which is
particularly preferably propylene. The olefin polymer generated by
polymerizing any one of these .alpha.-olefins alone or by
copolymerizing any combination of two or more kinds may be used. In
the present invention, the term "olefin polymer" connotes "olefin
copolymer".
[0021] Therefore, the low crystalline olefin polymer is
particularly preferably a low crystalline polypropylene. The
polypropylene may be copolymerized with the above-mentioned
.alpha.-olefin other than propylene as long as satisfying the
expression (a). In this case, the use ratio of the above-mentioned
.alpha.-olefin other than propylene is preferably 2% by mass or
less, more preferably 1% by mass or less based on the total amount
of propylene and the .alpha.-olefin other than propylene.
[0022] The low crystalline olefin polymers satisfying the
above-mentioned expression (a) may be used alone or in combination
with two or more kinds.
[0023] The low crystalline olefin polymer used in the present
invention is an olefin polymer satisfying the above-mentioned
expression (a). The olefin polymer preferably also satisfies the
above-mentioned condition (b). Specifically, the olefin polymer has
a low melting point of 0.degree. C. or more and less than
120.degree. C. When the melting point is 0.degree. C. or more, the
olefin polymer is hardly sticky or liquid. When the melting point
is less than 120.degree. C., the olefin polymer easily improves the
low temperature heat-sealing properties without the decreased
adhesion temperature between nonwoven fabrics being prevented. From
this viewpoint, the melting point is preferably 20.degree. C. or
more and less than 120.degree. C., more preferably from 20 to
100.degree. C., more preferably from 40 to 100.degree. C., further
more preferably from 50 to 90.degree. C., particularly preferably
from 60 to 80.degree. C.
[0024] The melting point is defined as the peak top of a melt
endothermic curve obtained by maintaining the temperature of 10 mg
of the sample at 230.degree. C. for 3 minutes and decreasing it to
0.degree. C. at 10.degree. C./minute; and then maintaining it
0.degree. C. for 3 minutes and increasing it at 10.degree.
C./minute, under a nitrogen atmosphere, by using a differential
scanning calorimeter (DSC-7 available from PerkinElmer, Inc.). The
melt endotherm in this case is defined as .DELTA.H.
[0025] The low crystalline olefin polymer used in the present
invention preferably satisfies the condition (c). Specifically, the
melt endotherm (.DELTA.H) is preferably from 1 to 100 J/g. When the
melt endotherm is 1 J/g or more, the low crystalline olefin polymer
is not completely amorphous or melted at room temperature. When the
melt endotherm is 100 J/g or less, the nonwoven fabric has a low
crystallinity so as to easily improve the low temperature
heat-sealing properties. From this viewpoint, the melt endotherm is
preferably from 2 to 90 J/g, more preferably from 2 to 60 J/g, more
preferably from 5 to 50 J/g, further more preferably from 10 to 50
J/g, particularly preferably from 15 to 40 J/g.
[0026] The low crystalline olefin polymer used in the present
invention is required to satisfy the following expression (a):
.DELTA.H.gtoreq.6.times.(Tm-140.degree. C.), (a)
preferably .DELTA.H.gtoreq.3.times.(Tm-120.degree. C.),
more preferably .DELTA.H.gtoreq.2.times.(Tm-100.degree. C.).
In the expression, .DELTA.H represents a melt endotherm, and Tm
represents a melting point.
[0027] The low crystalline olefin polymer used in the present
invention preferably has a crystallization temperature (Tc) of 10
to 60.degree. C., more preferably 20 to 50.degree. C., further more
preferably 30 to 40.degree. C. The melt flow rate (MFR) is
preferably 20 to 400 g/10 minutes, more preferably 20 to 200 g/10
minutes, further more preferably 20 to 100 g/10 minutes,
particularly preferably 40 to 80 g/10 minutes. The crystallization
temperature and the MFR are values measured by the respective
methods described in Examples.
[0028] The low crystalline olefin polymer used in the present
invention particularly preferably satisfies the following
expressions (d) to (i), which is more preferably a low crystalline
polypropylene satisfying the following expressions (d) to (i):
[mmmm]=20 to 60% by mol (d)
[rrrr]/(1-[mmmm]).ltoreq.0.1 (e)
[rmrm]>2.5% by mol (f)
[mm].times.[rr]/[mr].sup.2.ltoreq.2.0 (g)
Weight-average molecular weight (Mw)=10,000 to 200,000, and (h)
Molecular weight distribution (Mw/Mn)<4, (i)
wherein [mmmm] represents a mesopentad fraction, [rrrr] represents
a racemic pentad fraction, [rmrm] represents a
racemic-meso-racemic-meso pentad fraction, [mm] represents a
mesotriad fraction, [rr] represents a racemic triad fraction, and
[mr] represents a meso-racemic triad fraction. These values were
determined by the method described in Examples.
[0029] The above-mentioned expressions (d) to (i) will be explained
below in turn.
[mmmm]=20 to 60% by mol (d)
[0030] The low crystalline polypropylene suitably used in the
present invention has an [mmmm] (mesopentad fraction) of 20 to 60%
by mol. When the [mmmm] is 20% by mol or more, the
melt-solidification does not delay so as to avoid a sticky fiber.
Accordingly, the nonwoven fabric is not attached to a winding roll
but easily continuously formed. When the [mmmm] is 60% by mol or
less, the low temperature heat-sealing properties is excellent, the
crystallinity is not too high, and the elastic recovery properties
is also excellent. From this viewpoint, the [mmmm] is preferably 30
to 50% by mol, more preferably 40 to 50% by mol.
[rrrr]/(1-[mmmm]).ltoreq.0.1 (e)
[0031] The low crystalline polypropylene suitably used in the
present invention has an [rrrr]/(1-[mmmm]) of preferably 0.1 or
less. The [rrrr]/(1-[mmmm]) is an index representing the uniformity
of the regularity distribution of the low crystalline
polypropylene. If the value is too large, a mixture of a high
stereoregular polypropylene and an atactic polypropylene is
obtained like an ordinary polypropylene produced with an existing
catalyst and causes a sticky fiber. From this viewpoint,
[rrrr]/(1-[mmmm]) is preferably from 0.001 to 0.05, more preferably
from 0.001 to 0.04, further more preferably from 0.01 to 0.04.
[rmrm]>2.5% by mol (f)
[0032] The low crystalline polypropylene suitably used in the
present invention has an [rmrm] of more than 2.5% by mol. When the
[rmrm] is more than 2.5% by mol, the randomness of the low
crystalline polypropylene can be maintained. This avoids the
crystallinity to be increased due to crystallization caused by the
isotactic polypropylene bock chain so as not to decrease the
elastic recovery properties. From this viewpoint, the [rmrm] is
preferably 2.6% by mol or more, more preferably 2.7% by mol or
more. The upper limit is typically about 10% by mol, more
preferably 7% by mol, further more preferably 5% by mol,
particularly preferably 4% by mol.
[mm].times.[rr]/[mr].sup.2.ltoreq.2.0 (g)
[0033] The low crystalline polypropylene suitably used in the
present invention has an [mm].times.[rr]/[mr].sup.2 of preferably
2.0 or less. The [mm].times.[rr]/[mr].sup.2 is an index
representing the randomness of a polymer. When this value is 2.0 or
less, a fiber obtained by spinning has sufficient elastic recovery
properties and is controlled not to be sticky. From this viewpoint,
the [mm].times.[rr]/[mr].sup.2 is preferably more than 0.25 and 1.8
or less, more preferably from 0.5 to 1.8, further more preferably
from 1 to 1.8, particularly preferably from 1.2 to 1.6.
Weight-average molecular weight (Mw)=10,000 to 200,000 (h)
[0034] The low crystalline polypropylene suitably used in the
present invention has a weight-average molecular weight of 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 too
low but is moderate so as to avoid a broken thread upon spinning.
When the weight average molecular weight is 200,000 or less, the
viscosity of the low crystalline polypropylene is not too high to
increase the spinnability. From this viewpoint, the weight-average
molecular weight is preferably from 30,000 to 200,000, more
preferably from 40,000 to 150,000, further more preferably from
80,000 to 150,000, particularly preferably from 100,000 to
140,000.
Molecular weight distribution (Mw/Mn)<4 (i)
[0035] The low crystalline polypropylene suitably used in the
present invention has a molecular weight distribution (Mw/Mn) of
preferably less than 4. When the molecular weight distribution is
less than 4, the fiber obtained by spinning is controlled not to be
sticky. The molecular weight distribution is preferably 3 or less,
more preferably 2.5 or less, further more preferably from 1.5 to
2.5.
Process of Producing Low Crystalline Olefin Polymer:
[0036] As the process of producing a low crystalline olefin polymer
used in the present invention, the .alpha.-olefin such as propylene
is preferably polymerized or copolymerized by using a metallocene
catalyst obtained by combining (A) a transition metal compound
having a crosslinked structure through two crosslinking groups with
(B) a promoter. According to this process, a low crystalline olefin
polymer satisfying the above-mentioned expression (a) can be easily
produced.
[0037] Specifically, the .alpha.-olefin such as propylene is
polymerized or copolymerized in the presence of a polymerization
catalyst containing a promoter component (B) selected from a
transition metal compound (A) represented by the following general
formula (I); a compound (B-1) capable of forming an ionic complex
through reaction with a transition metal compound as the component
(A) or a derivative thereof; and an aluminoxane (B-2).
##STR00001##
[0038] In the general formula (I), M represents a metal element of
the groups 3 to 10 in the periodic table or of lanthanoid series;
E.sup.1 and E.sup.2 each represent a ligand selected from a
substituted cyclopentadienyl group, an indenyl group, a substituted
indenyl group, a heterocyclopentadienyl group, a substituted
heterocyclopentadienyl group, an amide group, a phosphide group, a
hydrocarbon group, and a silicon-containing group, forming a
crosslinked structure through A.sup.1 and A.sup.2, E.sup.1 and
E.sup.2 may be the same or different from each other; X represents
a r-bonding ligand, wherein when exist, a plurality of "X"s may be
the same or different from each other and may be crosslinked to
another X, E.sup.1, E.sup.2, or Y. Y represents a Lewis base,
wherein when exist, a plurality of "Y"s may be the same or
different from each other and may be crosslinked to another Y,
E.sup.1, E.sup.2, or X; A.sup.1 and A.sup.2 are each a divalent
crosslinking group bonding two ligands and each represent a
hydrocarbon group with 1 to 20 carbon atoms, a halogen-containing
hydrocarbon group with 1 to 20 carbon atoms, a silicon-containing
group, a germanium-containing group, a tin-containing group, --O--,
--CO--, --S--, --SO.sub.2--, --Se--, --NR.sup.1--, --PR.sup.1--,
--P(O)R.sup.1--, --BR.sup.1--, or --AlR.sup.1--, wherein R.sup.1
represents a hydrogen atom, a halogen atom, a hydrocarbon group
with 1 to 20 carbon atoms, or a halogen-containing hydrocarbon
group with 1 to 20 carbon atoms, and A.sup.1 and A.sup.2 may be the
same or different from each other. q represents an integer of 1 to
5, i.e., {(atomic valence of M)-2}; and r represents an integer of
0 to 3.
[0039] The specific example of the transition metal compound
represented by the general formula (I) includes
(1,2'-dimethylsilylene)(2,1'-dimethylsilylene)-bis(3-n-butylindenyl)zirco-
nium dichloride,
(1,2'-dimethylsilylene)(2,1'-dimethylsilylene)-bis(3-trimethylsilylmethyl-
indenyl)zirconium dichloride,
(1,2'-dimethylsilylene)(2,1'-dimethylsilylene)-bis(3-phenylindenyl)zircon-
ium dichloride,
(1,2'-dimethylsilylene)(2,1'-dimethylsilylene)-bis(4,5-benzoindenyl)zirco-
nium dichloride,
(1,2'-dimethylsilylene)(2,1'-dimethylsilylene)-bis(4-isopropylindenyl)zir-
conium dichloride, [0040]
(1,2'-dimethylsilylene)(2,1'-dimethylsilylene)-bis(5,6-dimethylindenyl)zi-
rconium dichloride,
(1,2'-dimethylsilylene)(2,1'-dimethylsilylene)-bis(4,7-di-isopropylindeny-
l)zirconium dichloride,
(1,2'-dimethylsilylene)(2,1'-dimethylsilylene)-bis(4-phenylindenyl)zircon-
ium dichloride,
(1,2'-dimethylsilylene)(2,1'-dimethylsilylene)-bis(3-methyl-4-isopropylin-
denyl)zirconium dichloride,
(1,2'-dimethylsilylene)(2,1'-dimethylsilylene)-bis(5,6-benzoindenyl)zirco-
nium dichloride,
(1,2'-dimethylsilylene)(2,1'-isopropylidene)-bis(indenyl)zirconium
dichloride,
(1,2'-dimethylsilylene)(2,1'-isopropylidene)-bis(3-methylindenyl)zirconiu-
m dichloride,
(1,2'-dimethylsilylene)(2,1'-isopropylidene)-bis(3-isopropylindenyl)zirco-
nium dichloride,
(1,2'-dimethylsilylene)(2,1'-isopropylidene)-bis(3-n-butylindenyl)zirconi-
um dichloride, and
(1,2'-dimethylsilylene)(2,1'-isopropylidene)-bis(3-trimethylsilylmethylin-
denyl) zirconium dichloride; and these compounds wherein the
zirconium is substituted with titanium or hafnium.
[0041] The component (B-1) as the component (B) includes dimethyl
anilinium tetrakis pentafluorophenyl borate, triethylammonium
tetraphenyl borate, tri-n-butylammonium tetraphenyl borate,
trimethylammonium tetraphenyl borate, tetraethylammonium
tetraphenyl borate, methyl (tri-n-butyl) ammonium tetraphenyl
borate, and benzyl (tri-n-butyl) ammonium tetraphenyl borate.
[0042] These components (B-1) may be used alone or in combination
with two or more kinds. On the other hand, the aluminoxane as the
component (B-2) includes methylaluminoxane, ethylaluminoxane, and
isobutylaluminoxane. These aluminoxanes may be used alone or in
combination with two or more kinds. Alternatively, one or more
kinds of the components (B-2) may be used together with one or more
kinds of the components (B-1).
[0043] As the above-mentioned polymerization catalyst, an
organoaluminum compound can be used as the component (C) in
addition to the above-mentioned components (A) and (B). The
organoaluminum compound as the component (C) includes
trimethylaluminum, triethylaluminum, triisopropylaluminum,
triisobutylaluminum, dimethylaluminum chloride, diethylaluminum
chloride, methylaluminum dichloride, ethylaluminum dichloride,
dimethylaluminum fluoride, diisobutylaluminum hydride,
diethylaluminum hydride, and ethylaluminum sesquichloride. These
organoaluminum compounds may be used alone or in combination with
two or more kinds. In the polymerization of propylene, at least one
kind of the catalytic components can be supported to a suitable
carrier.
[0044] The polymerization process is not limited in particular,
which may be conducted by slurry polymerization, gas phase
polymerization, bulk polymerization, solution polymerization,
suspension polymerization, or the like. However, bulk
polymerization and solution polymerization are particularly
preferable. The polymerization temperature is typically from
-100.degree. C. to 250.degree. C. The use ratio of the catalyst to
the reactive raw material "raw material monomer/component (A)"
(mole ratio) is preferably from 1 to 10.sup.8, more preferably from
10 to 10.sup.5, further more preferably from 10.sup.2 to 10.sup.5.
The polymerization time is typically preferably from 5 minutes to
10 hours. The reaction pressure is typically preferably from normal
pressure to 20 MPa (gauge pressure).
Crystalline Resin Composition:
[0045] The crystalline resin composition used in the present
invention contains 1 to 99% by mass of a low crystalline olefin
polymer. If the content of the olefin polymer is less than 1% by
mass, the low temperature heat-sealing properties of the nonwoven
fabric is scarcely improved. If the content of the olefin polymer
is more than 99% by mass, the moldability and the texture are
decreased due to the stickiness of the nonwoven fabric, and the
strength of the nonwoven fabric is also decreased. From this
viewpoint, the content of the olefin polymer is preferably 1 to 49%
by mass, more preferably 1 to 40% by mass, further more preferably
3 to 40% by mass. The preferable range when the single fiber is
used may be different from that when the core-sheath composite
fiber is used. The preferable ranges in the respective cases will
be described below.
[0046] The crystalline resin composition may contain another
thermoplastic resin and an additive as the components other than
the low crystalline olefin polymer.
[0047] Such a thermoplastic resin includes, for example, the high
crystalline olefin polymer, an ethylene-vinyl acetate copolymer, a
hydrogenated styrene elastomer, a polyester resin, and a polyamide
resin. These may be used alone or in combination with two or more
kinds. In these thermoplastic resins, the high crystalline olefin
polymer is preferable from the viewpoint of compatibility, textile,
flexibility, and the like. The melting point (Tm) of the high
crystalline olefin polymer is preferably from 120 to 200.degree.
C., more preferably from 130 to 180.degree. C., further more
preferably from 150 to 175.degree. C. The melt endotherm (.DELTA.H)
is preferably from 50 to 200 J/g, more preferably from 55 to 190
J/g, more preferably from 60 to 150 J/g, more preferably from 70 to
130 J/g, further more preferably from 70 to 110 J/g, particularly
preferably from 80 to 110 J/g. The melt flow rate (MFR) of the high
crystalline olefin polymer is preferably from 1 to 100 g/10
minutes, more preferably from 10 to 80 g/10 minutes, further more
preferably from 15 to 80 g/10 minutes, particularly preferably from
15 to 50 g/10 minutes. Such a high crystalline olefin polymer can
easily be produced by the method described in JPA-2006-103147 or
the like.
[0048] The high crystalline olefin polymer is preferably an olefin
polymer generated by polymerizing one or more kinds of monomers
selected from ethylene and .alpha.-olefins with 3 to 28 carbon
atoms, particularly preferably an olefin polymer generated by
polymerizing one or more kinds of monomers selected from
.alpha.-olefins with 3 to 28 carbon atoms. These .alpha.-olefins
can be illustrated by the above-mentioned ones. The high
crystalline olefin polymer is particularly preferably a propylene
homopolymer, a propylene-ethylene random copolymer, a
propylene-ethylene-1-butene random copolymer, and a
propylene-ethylene block copolymer, more preferably a propylene
homopolymer (polypropylene).
[0049] As the additive, conventionally well-known additives can be
mixed, including, for example, a foaming agent, a crystal
nucleating agent, a weathering stabilizer, an ultraviolet absorber,
a photostabilizer, a heat-resistant stabilizer, an antistatic
agent, a release agent, a flame retarder, a synthetic oil, a wax,
an electric property modifier, an antislip agent, an antiblocking
agent, a viscosity modifier, a color protector, an anticlouding
agent, a lubricant, pigment, a dye, a plasticizer, a softener, an
anti-aging agent, a hydrochloric acid absorbent, a chlorine
scavenger, an antioxidant, and an anti-adhesive agent.
[0050] In the crystalline resin composition used in the present
invention, the component as the low crystalline polyolefin melts so
as to provide the heat-sealing properties (thermal adhesiveness) as
long as the heat-sealing temperature is higher than the melting
point of the low crystalline polyolefin even if being lower than
the melting points of the thermoplastic resin and the additive.
[0051] Based on such a principle, the composition consisting of a
high crystalline polyolefin and a low crystalline polyolefin rather
than only a high crystalline polyolefin can provide the heat
sealing at low temperature. Particularly, the heat-sealing strength
increases as the low crystalline polyolefin content increases.
Nonwoven Fabric:
[0052] The nonwoven fabric of the present invention includes (1)
one or more layers, wherein at least one of the layers is formed by
using a crystalline resin composition containing 1 to 99% by mass
of a low crystalline olefin polymer satisfying the expression (a).
Specifically, the nonwoven fabric of the present invention takes
any one of the following embodiments 1 to 3.
Embodiment 1
[0053] The nonwoven fabric includes one layer formed by using a
crystalline resin composition containing 1 to 99% by mass of a low
crystalline olefin polymer satisfying the expression (a).
Embodiment 2
[0054] The nonwoven fabric includes two layers, wherein at least
one of the layers is formed by using a crystalline resin
composition and the crystalline resin composition contains 1 to 99%
by mass of a low crystalline olefin polymer satisfying the
expression (a).
Embodiment 3
[0055] The nonwoven fabric includes three or more layers, wherein
at least one of the both outermost layers when the nonwoven fabric
has three or more layers is formed by using a crystalline resin
composition containing 1 to 99% by mass of a low crystalline olefin
polymer satisfying the expression (a).
[0056] In the nonwoven fabric including two layers of Embodiment 2,
the two layers are preferably formed by using the crystalline resin
composition.
[0057] In the nonwoven fabric including three or more layers of
Embodiment 3, the both outermost layers are preferably formed by
using the crystalline resin composition. In the example of the
nonwoven fabric consisting of the three layers (AA)/(BB)/(CC), the
both outermost layers are the layers (AA) and (CC). In the present
invention, at least one of the outermost layers (AA) and (CC) only
needs to be formed by using the crystalline resin composition. The
both outermost layers may be formed by using the crystalline resin
composition.
[0058] In the nonwoven fabric (1), the content of the low
crystalline olefin polymer in the crystalline resin composition is
preferably 1 to 49% by mass, more preferably 3 to 49% by mass,
further more preferably 3 to 30% by mass from the viewpoint of the
low temperature heat-sealing properties. Particularly, from the
viewpoint of significantly improving the low temperature
heat-sealing properties, the content of the low crystalline olefin
polymer is preferably 7 to 99% by mass, more preferably 7 to 49% by
mass, further more preferably 7 to 30% by mass.
[0059] In the nonwoven fabric consisting of three or more layers of
Embodiment 3, the ratio of the outermost layer formed by using the
crystalline resin composition to all the layers is preferably from
1 to 99%, more preferably from 1 to 60%, more preferably from 5 to
60%, more preferably from 10 to 60%, further more preferably from
20 to 60%, particularly preferably from 40 to 60% based on areal
weight from the viewpoint of the low temperature heat-sealing
properties. The areal weight means the weight per unit area.
[0060] When the ratio of the outermost layer to all the layers is
large, the low temperature heat-sealing properties is preferably
more excellent. When the ratio is small, the strength of the
nonwoven fabric is preferably increased with excellent low
temperature heat-sealing properties.
[0061] A layer not formed by using the crystalline resin
composition when exists in the nonwoven fabric consisting of two
layers of Embodiment 2 and a layer not formed by using the
crystalline resin composition in the nonwoven fabric consisting of
three or more layers of Embodiment 3 have any component without
particular limitation. As the component, typical thermoplastic
resins used for a nonwoven fabric can be used. Among these, the
high crystalline olefin polymer is preferable, and the high
crystalline polypropylene is more preferable. These layers may
contain a thermoplastic resin and an additive that can be used with
the crystalline resin composition.
Nonwoven Fabric Formed by Using Core-Sheath Composite Fiber:
[0062] The nonwoven fabric of the present invention includes (2)
one or more layers, wherein the layers each consist of a fiber, the
fiber of at least one of the layers is a core-sheath composite
fiber containing a crystalline resin composition as the sheath
component, the ratio of the sheath component is 1 to 99% by mass
based on the total amount of the core component and the sheath
component, and the crystalline resin composition contains 1 to 99%
by mass of a low crystalline olefin polymer satisfying the
expression (a). Specifically, the nonwoven fabric of the present
invention takes any one of the following embodiments 4 to 6.
Embodiment 4
[0063] The nonwoven fabric includes one layer consisting of a
fiber, wherein the fiber is a core-sheath composite fiber
containing a crystalline resin composition as the sheath component,
the ratio of the sheath component is 1 to 99% by mass based on the
total amount of the core component and the sheath component, and
the crystalline resin composition contains 1 to 99% by mass of a
low crystalline olefin polymer satisfying the expression (a).
Embodiment 5
[0064] The nonwoven fabric includes two layers, wherein the layers
each consist of a fiber, the fiber of at least one of the layers is
a core-sheath composite fiber containing a crystalline resin
composition as the sheath component, the ratio of the sheath
component is 1 to 99% by mass based on the total amount of the core
component and the sheath component, and the crystalline resin
composition contains 1 to 99% by mass of a low crystalline olefin
polymer satisfying the following expression (a).
Embodiment 6
[0065] The nonwoven fabric includes three or more layers, wherein
the layers each consist of a fiber, the fibers of the both
outermost layers each are a core-sheath composite fiber containing
a crystalline resin composition as the sheath component, the ratio
of the sheath component is 1 to 99% by mass based on the total
amount of the core component and the sheath component, and the
crystalline resin composition contains 1 to 99% by mass of a low
crystalline olefin polymer satisfying the expression (a).
[0066] The crystalline resin composition may contain another
thermoplastic resin and an additive as the components other than
the low crystalline olefin polymer, as described above.
[0067] The content of the core-sheath composite fiber in such a
nonwoven fabric is preferably 1 to 100% by mass, more preferably 10
to 100% by mass, more preferably 30 to 100% by mass, more
preferably 50 to 100% by mass, more preferably 70 to 100% by mass,
further more preferably 80 to 100% by mass, particularly preferably
90 to 100% by mass, most preferably substantially 100% by mass.
[0068] The ratio of the sheath component in the core-sheath
composite fiber is required to be 1 to 99% by mass based on the
total amount of the core component and the sheath component from
the viewpoint of the heat-sealing strength and the low temperature
heat-sealing properties. If the ratio of the sheath component is
less than 1% by mass, the thickness of the sheath part is decreased
too much so as not to provide the low temperature heat-sealing
properties of the nonwoven fabric. If the ratio is more than 99% by
mass, the strength of the nonwoven fabric is decreased. From this
viewpoint, the ratio of the sheath component is preferably 1 to 49%
by mass, more preferably 5 to 49% by mass, more preferably 15 to
49% by mass, further more preferably 25 to 49% by mass,
particularly preferably 30 to 49% by mass based on the total amount
of the core component and the sheath component.
[0069] In the nonwoven fabric consisting of two layers of
Embodiment 5, fibers composing the both two layers each are
preferably a core-sheath composite fiber containing the crystalline
resin composition as the sheath component. In the nonwoven fabric
consisting of three or more layers of Embodiment 6, fibers
composing the both outermost layers each are preferably a
core-sheath composite fiber containing the crystalline resin
composition as the sheath component.
[0070] In the nonwoven fabric (2), the content of the low
crystalline olefin polymer in the crystalline resin composition is
preferably 1 to 49% by mass, more preferably 3 to 49% by mass, more
preferably 3 to 40% by mass, further more preferably 10 to 40% by
mass, particularly preferably 15 to 35% by mass from the viewpoint
of the low temperature heat-sealing properties.
[0071] In the nonwoven fabric consisting of three or more layers of
Embodiment 6, the ratio of the outermost layer formed by using the
crystalline resin composition to all the layers is preferably from
1 to 99%, more preferably from 1 to 60%, more preferably from 5 to
60%, more preferably from 10 to 60%, further more preferably from
20 to 60%, particularly preferably from 40 to 60% based on areal
weight from the viewpoint of the low temperature heat-sealing
properties.
[0072] In the core-sheath composite fiber, the sheath component is
as described above. The core component is not limited in
particular. As the core component, typical thermoplastic resins or
compositions containing these thermoplastic resins used for a
nonwoven fabric can be used. Among these thermoplastic resins, the
high crystalline olefin polymer is preferable, and the high
crystalline polypropylene is more preferable. The core component
may contain another thermoplastic resin and an additive in the same
way as the crystalline resin composition in the sheath component.
As the core component, the crystalline resin composition defined as
a sheath component may be used as long as being different from the
sheath component to be used.
[0073] A layer formed by using a fiber other than the core-sheath
composite fiber when exists in the nonwoven fabric consisting of
two layers and the layer formed by using a fiber other than the
core-sheath composite fiber in the nonwoven fabric consisting of
three or more layers each have any component without particular
limitation. As the component, a typical thermoplastic resin used
for a nonwoven fabric can be used. However, among these, the high
crystalline olefin polymer is preferable, and the high crystalline
polypropylene is more preferable. As the component of these layers
may contain a thermoplastic resin and an additive in the same way
as the crystalline resin composition described above. The fiber of
the layer formed by using a fiber other than the core-sheath
composite fiber may be a core-sheath composite fiber departed from
the above-mentioned range. However, a single fiber is preferable
unless necessary.
[0074] In the core-sheath composite fiber, the difference between
the melting points of a thermoplastic resin composing the core
component and a component composing the sheath component (i.e. at
least one of the low crystalline olefin polymer contained in the
crystalline resin composition; and a thermoplastic resin and an
additive as the components other than the low crystalline olefin
polymer) is preferably less than 20.degree. C. from the viewpoint
of the strength of the nonwoven fabric and the spinnability. The
difference between these melting points is more preferably
18.degree. C. or less, further more preferably 15.degree. C. or
less. Particularly, the core-sheath composite fiber preferably
contains materials with the same melting point.
Method of Producing Nonwoven Fabric:
[0075] The method of producing the nonwoven fabric of the present
invention is not limited in particular. As the method, a well-known
dry method, wet method, spunbond method (including melt-blow
method), and the like can be used. Among these, a spunbond method
is preferable. A nonwoven fabric produced by a spunbond method is
hereinafter referred to as a spunbond nonwoven fabric.
[0076] Typically, in the spunbond method, the nonwoven fabric is
produced in such a manner that a melt-kneaded crystalline resin
composition is spun, stretched, and filamentized to form continuous
long fibers. In the subsequent process, the continuous long fibers
are accumulated and entangled on a moving collecting surface. In
this method, a nonwoven fabric may be produced continuously, which
has a large strength since fibers composing the nonwoven fabric are
stretched continuous long fibers.
[0077] As the spunbond method, conventional well-known methods can
be used. Fiber can be produced by extruding a molten polymer, for
example, from a large nozzle with several thousands of pores or a
group of small nozzles with about 40 pores. The ejection amount of
fiber per single pore is preferably from 0.1 to 1 g/minute, more
preferably from 0.3 to 0.7 g/minute. After ejected from the nozzle,
melt fiber is cooled by a cross-flow cold air system, drawn away
from the nozzle, and stretched by high-speed airflow. Generally,
there exist two kinds of air-damping, both of which use a venturi
effect. In the first air-damping, a filament is 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, a filament is stretched through a nozzle or a suction
gun. A filament formed by this air-damping is collected to form a
web on a screen (wire) or a pore forming belt. Subsequently, the
web passes a compression roll and then between heating calendar
rolls; and bounded at the part where the embossment part on one
roll includes from 10 to 40% of the area of the web to form a
nonwoven fabric.
[0078] As the bonding, thermal bonding including emboss, hot air,
and calendar, adhesive bonding, and mechanical bonding including
needle punch and water punch can be used.
[0079] The method of producing a multilayered nonwoven fabric is
also not limited in particular. The multilayered nonwoven fabric
can be produced by a well-known method. For example, a first
nonwoven fabric is produced by using a crystalline resin
composition containing the low crystalline olefin polymer. On the
first nonwoven fabric, a second nonwoven fabric is formed by a
spunbond method, a melt blowing method, or the like. Optionally, a
third nonwoven fabric is overlaid on the second layer and
fusion-bounded by being heated under pressure. There are various
laminate means for forming the multilayered nonwoven fabric, such
as thermal bonding and adhesive bonding. A convenient and
inexpensive thermal bonding, particularly heat embossing roll can
also be used. The heat embossing roll can conduct lamination with a
well-known laminate device equipped with an embossing roll and a
flat roll. As the embossing roll, emboss patterns of various shapes
can be used, which include a lattice pattern wherein each adhesion
part is consecutive, an independent lattice pattern, and arbitrary
distribution.
[0080] In the present invention, the flexibility of the nonwoven
fabric can be controlled by adjusting the temperature and the
spinning speed during embossing.
[0081] When the spunbond nonwoven fabric with high flexibility is
obtained by controlling the temperature during embossing, the
temperature preferably falls within the range of from 90 to
130.degree. C. When the embossing temperature is 90.degree. C. or
more, fibers sufficiently fuses with each other to increase the
strength of the nonwoven fabric. When the embossing temperature is
130.degree. C. or less, the low crystalline olefin polymer may not
completely melt into a film so as to form a nonwoven fabric with
high flexibility.
[0082] The textile product formed by using the nonwoven fabric of
the present invention, for example, can includes a material for a
disposable diaper, an elastic material for a diaper cover, an
elastic material for a sanitary product, an elastic material for a
hygienic product, an elastic tape, an adhesive plaster, an elastic
material for a clothing material, an electric insulating material
for a clothing material, a thermal insulating material for a
clothing material, a protective garment, a headwear, a face mask, a
glove, an athletic supporter, an elastic bandage, a base cloth for
a wet dressing, an antislipping base cloth, a vibration dampener, a
finger stall, an air filter for a clean room, an electret filter, a
separator, a thermal insulating material, a coffee bag, a food
packaging material, a ceiling surface material for an automobile,
an acoustic insulating material, a cushioning material, a dust
proof material for a speaker, an air cleaner material, an insulator
surface material, a backing material, an adhesive nonwoven fabric
sheet, various automobile members including a door trim material,
various cleaning materials including a cleaning material for a
copying machine, a surface material and a backing material of a
carpet, an agricultural rolled cloth, a wood draining material, a
shoe material such as a surface material for sport shoes, a member
for a bag, an industrial sealant, a wiping material, and a bed
sheet. In particular, the nonwoven fabric of the present invention
is preferably used for a hygienic product such as a paper
diaper.
EXAMPLES
[0083] The present invention will be more specifically explained
with reference to Examples but is not limited thereto.
[0084] Each of the physical properties of the low crystalline
polypropylene obtained in the following Preparation Example 1 was
measured as follows.
Measurement of Melting Point:
[0085] The melting point (Tm) was determined as the peak top
observed on the highest temperature side of a melt endothermic
curve obtained by maintaining the temperature of 10 mg of the
sample at -10.degree. C. for 5 minutes and then increasing it at
10.degree. C./minute by using a differential scanning calorimeter
(DSC-7 available from PerkinElmer, Inc.) under a nitrogen
atmosphere.
Measurement of Crystallization Temperature:
[0086] The crystallization temperature (Tc) was determined as the
peak top observed on the highest temperature side of an exothermic
curve obtained by maintaining the temperature of 10 mg of the
sample at 220.degree. C. for 5 minutes and then decreasing it to
-30.degree. C. at 20.degree. C./minute by using a differential
scanning calorimeter (DSC-7 available from PerkinElmer, Inc.) under
a nitrogen atmosphere.
Evaluation of Stereoregularity: NMR Measurement
[0087] 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,
vol. 8, p. 687 (1975)".
[0088] Device: .sup.13C-NMR spectrometer, JNM-EX400 series
available from JEOL, Ltd.
[0089] Method: proton complete decoupling
[0090] Concentration: 220 mg/mL
[0091] Solvent: mixed solvent of 1,2,4-trichlorobenzene and
deuterated benzene at 90:10 (volume ratio)
[0092] Temperature: 130.degree. C.
[0093] Pulse width: 45.degree.
[0094] Pulse repetition time: 4 seconds
[0095] Accumulation: 10,000 times
[0096] Calculating Expressions:
M=m/S.times.100
R=.gamma./S.times.100
S.dbd.P.beta..beta.+P.alpha..beta.+P.alpha..gamma.
[0097] S: Signal intensity of carbon atoms in side chain methyl of
all the propylene units
[0098] P.beta..beta.: 19.8 to 22.5 ppm
[0099] P.alpha..beta.: 18.0 to 17.5 ppm
[0100] P.alpha..gamma.: 17.5 to 17.1 ppm
[0101] .gamma.: racemic pentad chain, 20.7 to 20.3 ppm
[0102] m: mesopentad chain, 21.7 to 22.5 ppm
[0103] The mesopentad fraction [mmmm], the racemic pentad fraction
[rrrr] and the racemic-meso-racemic-meso pentad fraction [rmrm] are
measured in accordance with the method proposed by A. Zambelli, et
al., "Macromolecules, vol. 6, p. 925 (1973)", 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. The triad fractions [mm], [rr], and [mr] were also
calculated by the above-mentioned method.
Measurement of Weight-Average Molecular Weight (Mw) and Molecular
Weight Distribution (Mw/Mn):
[0104] The weight average molecular weight (Mw) and the molecular
weight distribution (Mw/Mn) were determined by gel permeation
chromatography (GPC). The following device and conditions were used
in this measurement to obtain a polystyrene conversion weight
average molecular weight.
GPC Device
[0105] Column: TOSO GMHHR-H(S)HT
[0106] Detector: RI detector for liquid chromatography, Waters
150C
Measurement Conditions
[0107] Solvent: 1,2,4-trichlorobenzene
[0108] Measurement temperature: 145.degree. C.
[0109] Flow rate: 1.0 mL/minute
[0110] Sample concentration: 2.2 mg/mL
[0111] Injection amount: 160 .mu.L
[0112] Calibration curve: Universal Calibration
[0113] Analysis software: HT-GPC (ver. 1.0)
Measurement of Melt Flow Rate (MFR):
[0114] The MFR was measured at a temperature of 230.degree. C.
under a weight of 21.18 N in accordance with JIS K7210.
Preparation Example 1
Low Crystalline Polypropylene
[0115] In a stainless steel reactor equipped with a stirrer, the
inner capacity of which is 20 L, n-heptane, triisobutylaluminum,
and a catalyst component which was obtained by bringing dimethyl
anilinium tetrakis pentafluorophenyl borate,
(1,2'-dimethylsilylene)
(2,1'-dimethylsilylene)-bis(3-trimethylsilylmethylindenyl)zirconium
dichloride, triisobutylaluminum, and propylene into contact with
each other in a mass ratio of 1:2:20 in terms of zirconium were
continuously fed at 20 L/h, 15 mmol/h, and 6 .mu.mol/h,
respectively.
[0116] The mixture was polymerized at a polymerization temperature
set at 67.degree. C. by continuously feeding propylene and hydrogen
to maintain a hydrogen concentration of 0.8% by mol in the gas
phase of the reactor and a total pressure of 0.7 MPa in the reactor
(gauge pressure).
[0117] In the obtained polymerization solution, "Irganox 1010"
(available from Ciba Specialty Chemicals Co., Ltd.) as a stabilizer
was added so that the content ratio is 500 ppm by mass.
Subsequently, n-heptane as a solvent was removed to obtain a low
crystalline polypropylene with the physical properties shown in
Table 1.
TABLE-US-00001 TABLE 1 Preparation Example 1 (b) Melting point (Tm)
(.degree. C.) 70 (c) Melt endotherm (.DELTA.H) (J/g) 28 (a)
.DELTA.H .gtoreq. 6 .times. (Tm-140.degree. C.) Satisfied
Crystallization temperature (Tc) (.degree. C.) 36 [mm] (% by mol)
63.6 (d) [mmmm] (% by mol) 46.5 (e) [rrrr]/(1 - [mmmm]) 0.036 (f)
[rmrm] (% by mol) 3.0 (g) [mm] .times. [rr]/[mr].sup.2 1.4 (h) Mw
120,000 (i) Mw/Mn 2.0 MFR (g/10 minutes) 60
[0118] The heat-sealing strengths of the spunbond nonwoven fabrics
obtained in the following Examples 1 and 2 and Comparative Example
1 were measured at each temperature as described below. Measurement
of heat-sealing strength
[0119] A test piece with a length of 200 mm and a width of 40 mm
was taken from the obtained nonwoven fabric in the machine
direction (MD). Two nonwoven fabrics were heat-sealed at
165.degree. C., 170.degree. C., or 175.degree. C. under a pressure
of 0.2 MPa for 2 seconds with a heat sealing tester (heat gradient
tester available from TOYO SEIKI KOGYO CO. LTD). Five heat blocks
are connected, the thermal bonding area of each block is 250
mm.sup.2 (25 mm.times.10 mm).
[0120] For the nonwoven fabric sample heat-sealed as described
above, the unbounded parts of two nonwoven fabric samples each were
gripped with a chuck and elongated at a tension rate of 200
mm/minute, and the load capacity when the nonwoven fabrics were
released from each other was measured, with a tensile tester
(autograph 201 type available from INTESCO), so as to determine the
heat-sealing strength. When the nonwoven fabrics were broken before
released from each other, "Broken" was wrote down in the tables
herein.
Example 1
Production of Multilayered Spunbond Nonwoven Fabric
[0121] The low crystalline polypropylene obtained in Preparation
Example 1 was mixed with a high crystalline polypropylene (PP,
NOVATEC SA03 available from Japan Polypropylene Corporation, MFR=30
g/10 minutes, melting point=about 164.degree. C., melt endotherm=94
J/g) in a mixing ratio of 10 and 90% by mass, respectively, to
obtain a crystalline resin composition. The obtained crystalline
resin composition was used to produce a nonwoven fabric with a
spunbonding device as described below.
[0122] The raw materials were spun so that the materials were
melt-extruded with a single screw extruder at a resin temperature
of 230.degree. C. and so that the melt-extruded materials were
ejected from a core-sheath composite nozzle with a nozzle diameter
of 0.3 mm (the number of pores: 841) at a rate of 0.5 g/minute per
single pore. The spun fiber was sucked at an ejector pressure of
2.0 kg/cm.sup.2 while being cooled by air and then was laminated on
a net surface moving at a line speed of 49 m/min to obtain a
nonwoven fabric (S) (first layer).
[0123] On this nonwoven fabric (S), the high crystalline
polypropylene fiber is directly deposited by the above-mentioned
spunbond method to form a spunbond nonwoven fabric (C) (second
layer). Furthermore, a nonwoven fabric (S) (third layer) separately
produced in the same way as the first layer was overlaid. The
overlaid nonwoven fabrics were fusion-bound at a high temperature
under pressure with a heated roll with a temperature of 135.degree.
C. to obtain a multilayered nonwoven fabric with the structure of
spunbond nonwoven fabric (S)/spunbond nonwoven fabric (C)/spunbond
nonwoven fabric (S). Table 2 shows the areal weight (gsm:
g/m.sup.2) of the each layer and the heat-sealing strength at a
predetermined temperature of the obtained nonwoven fabric.
Example 2
Production of Multilayered Spunbond Nonwoven Fabric
[0124] A spunbond nonwoven fabric cloth (S) was produced in the
same way as Example 1 except that the low crystalline polypropylene
was mixed with the high crystalline polypropylene (PP, NOVATEC SA03
available from Japan Polypropylene Corporation) in a mixing ratio
of 5 and 95% by mass, respectively, to obtain a crystalline resin
composition. Table 2 shows the areal weight (gsm: g/m.sup.2) of the
each layer and the heat-sealing strength at a predetermined
temperature of the obtained nonwoven fabric.
Comparative Example 1
Production of Multilayered Spunbond Nonwoven Fabric
[0125] A spunbond nonwoven fabric (S) was produced in the same way
as Example 1 except that a crystalline resin composition consisting
of only the high crystalline polypropylene (PP, NOVATEC SA03
available from Japan Polypropylene Corporation) was used. Table 2
shows the areal weight (gsm: g/m.sup.2) of the each layer and the
heat-sealing strength at a predetermined temperature of the
obtained nonwoven fabric.
TABLE-US-00002 TABLE 2 Comparative Example Example 1 2 1
Multilayered First High crystalline polypropylene 90 95 100
nonwoven fabric layer Low crystalline polypropylene with low
melting point 10 5 0 composition (S) (Preparation Example 1) Areal
weight (gsm) 4 4 4 Second High crystalline polypropylene 100 100
100 layer Areal weight (gsm) 8 8 8 (C) Third High crystalline
polypropylene 90 95 100 layer Low crystalline polypropylene with
low melting point 10 5 0 (S) (Preparation Example 1) Areal weight
(gsm) 4 4 4 Properties of nonwoven Heat-sealing Heat-sealing
temperature: 165.degree. C. 4 2 0 fabric strength (gf) Heat-sealing
temperature: 170.degree. C. 80 37 26 Heat-sealing temperature:
175.degree. C. Broken 271 265
[0126] Table 2 shows that the multilayered nonwoven fabric produced
in Example 1 exhibits a significantly higher heat-sealing strength,
particularly at 170 to 175.degree. C. than that produced in
Comparative Example 1. Table 2 also shows that Example 1 obtains a
heat-sealing strength of 30 gf or more (70 gf or more in the higher
case) at 170.degree. C. and of 270 gf or more at 175.degree. C.
Therefore, it is clear that Example 1 has excellent low temperature
heat-sealing properties. The multilayered nonwoven fabric produced
with Example 2 has also excellent low temperature heat-sealing
properties compared with that produced with Comparative Example 1.
In the first and the third layers, it is clear that Example 1
wherein the content of the low crystalline polypropylene is 10% by
mass increased the low temperature heat-sealing properties more
significantly than Example 2 wherein that is 5% by mass.
[0127] The heat-sealing strengths of the spunbond nonwoven fabric
cloths obtained in the following Examples 3 to 5 and Comparative
Example 2 were measured at a predetermined temperature as described
above.
Example 3
Production of Spunbond Nonwoven Fabric Formed by Using Core-Sheath
Composite Fiber
[0128] As the sheath component, the low crystalline polypropylene
obtained in Preparation Example 1 was mixed with the high
crystalline polypropylene (PP, NOVATEC SA03 available from Japan
Polypropylene Corporation) in a mixing ratio of 25 and 75% by mass,
respectively, to obtain a crystalline resin composition. As the
core component, only the high crystalline polypropylene (PP,
NOVATEC SA03 available from Japan Polypropylene Corporation) was
used. These components were used to produce a nonwoven fabric with
a spunbonding device as described below.
[0129] The raw materials of the sheath component resin and the core
component resin were spun so that the materials were each
separately melt-extruded with a single screw extruder at a resin
temperature of 230.degree. C. and so that the melt-extruded
materials were ejected from a core-sheath composite nozzle with a
nozzle diameter of 0.6 mm (the number of pores: 797) at a rate of
0.5 g/minute per single pore at a ratio of the sheath component
[sheath/(core+sheath)] of 40% by mass.
[0130] The spun fiber was sucked at an ejector pressure of 2.0
kg/cm.sup.2 while being cooled by air and then was laminated on a
net surface moving at a line speed of 45 m/min. The fiber bundle
laminated on the net surface was embossed with an embossing roll
heated to 115.degree. C. under a line pressure of 40 kg/cm and
wound to a winding roll.
[0131] Table 3 shows the heat-sealing strength at a predetermined
temperature of the obtained nonwoven fabric.
Example 4
Production of Spunbond Nonwoven Fabric Formed by Using Core-Sheath
Composite Fiber
[0132] The nonwoven fabric was produced in the same way as Example
3 except that the melt-extruded materials were ejected in a ratio
of the sheath component [sheath/(core+sheath)] of 20% by mass.
[0133] Table 3 shows the heat-sealing strength at a predetermined
temperature of the obtained nonwoven fabric.
Example 5
Production of Spunbond Nonwoven Fabric Formed by Using Core-Sheath
Composite Fiber
[0134] The nonwoven fabric was produced in the same way as Example
3 except that the melt-extruded materials were ejected in a ratio
of the sheath component [sheath/(core+sheath)] of 10% by mass.
[0135] Table 3 shows the heat-sealing strength at a predetermined
temperature of the obtained nonwoven fabric.
Comparative Example 2
[0136] The nonwoven fabric was produced in the same way as Example
3 except that the high crystalline polypropylene (PP, NOVATEC SA03
available from Japan Polypropylene Corporation, MFR=30 g/10
minutes, melting point=about 164.degree. C., melt endotherm=94 J/g)
was used as the sheath component.
[0137] Table 3 shows the heat-sealing strength at a predetermined
temperature of the obtained nonwoven fabric.
TABLE-US-00003 TABLE 3 Comparative Example Example 3 4 5 2 Fiber
Core High crystalline polypropylene 100 100 100 100 composition
component (% by mass) Sheath High crystalline polypropylene 75 75
75 100 component Low crystalline polypropylene with low 25 25 25 0
(% by mass) melting point (Preparation Example 1) [Sheath
component/(Sheath component + Core component)] 40 20 10 20 (% by
mass) Properties of Heat-sealing Heat-sealing temperature:
165.degree. C. 63 46 42 0 nonwoven strength (gf) Heat-sealing
temperature: 170.degree. C. 442 264 200 20 fabric Heat-sealing
temperature: 175.degree. C. Broken Broken Broken 176
[0138] Table 3 shows that the multilayered nonwoven fabrics
produced in Examples 3 to 5 exhibit a significantly higher
heat-sealing strength, particularly at 165 to 175.degree. C. than
that produced in Comparative Example 2. Table 3 also shows that
Examples 3 to 5 obtain a heat-sealing strength of 40 gf or more at
165.degree. C. and of 200 gf (400 gf or more in the higher case) at
170.degree. C. and a heat-sealing strength enough to be broken at
175.degree. C. Therefore, it is clear that Examples 3 to 5 have
excellent low temperature heat-sealing properties.
INDUSTRIAL APPLICABILITY
[0139] The nonwoven fabric of the present invention is useful for,
for example, a material for a disposable diaper, an elastic
material for a diaper cover, an elastic material for a sanitary
product, an elastic material for a hygienic product, an elastic
tape, an adhesive plaster, an elastic material for a clothing
material, an electric insulating material for a clothing material,
a thermal insulating material for a clothing material, a protective
garment, a headwear, a face mask, a glove, an athletic supporter,
an elastic bandage, a base cloth for a wet dressing, an
antislipping base cloth, a vibration dampener, a finger stall, an
air filter for a clean room, an electret filter, a separator, a
thermal insulating material, a coffee bag, a food packaging
material, a ceiling surface material for an automobile, an acoustic
insulating material, a cushioning material, a dust proof material
for a speaker, an air cleaner material, an insulator surface
material, a backing material, an adhesive nonwoven fabric sheet,
various automobile members including a door trim material, various
cleaning materials including a cleaning material for a copying
machine, a surface material and a backing material of a carpet, an
agricultural rolled cloth, a wood draining material, a shoe
material such as a surface material for sport shoes, a member for a
bag, an industrial sealant, a wiping material, and a bed sheet. In
particular, the nonwoven fabric of the present invention is
preferably used for a hygienic product such as a paper diaper.
* * * * *