Technical Field
[0001] The present invention relates to a nonwoven fabric layered body, a cover sheet and an
absorbent article.
[0002] Since spunbond nonwoven fabrics are excellent in air permeability, flexibility, and the
like, they are used as absorbent articles such as paper diapers and sanitary napkins, but further
improvement in properties is required. For example, from the viewpoint of improving properties
such as bulkiness, use of a crimped spunbond nonwoven fabric including a crimped fiber, and a
nonwoven fabric layered body in which a plurality of crimped spunbond nonwoven fabric layers
are stacked are being studied.
[0003] A spunbond nonwoven fabric layered body having a plurality of spunbond nonwoven
fabric layers is proposed, in which at least two and up to four spunbond nonwoven fabric layers
include or consist of crimped endless filaments, the crimping degree of the filaments in these
spunbond nonwoven fabrics is different, the crimped filaments of the spunbond nonwoven fabric
layers each have a crimp number of at least 2 loops per 1 cm of their length, and the crimped
filaments of the spunbond nonwoven fabric layers are configured as bicomponent filaments using
the first plastic component and the second plastic component, and each of the plastic components
is present in each of the filaments in a proportion of at least 10% by weight (for example, see
Patent Document 1).
Further, In Patent Document 1, The spunbond nonwoven fabric layered body is proposed,
in which the crimping degree of the spunbond nonwoven fabric layers placed on top of each other
increases from the bottom to the top.
[0004] A spunbond nonwoven fabric including crimped multicomponent fibers is proposed, in
which the first component of the multicomponent fibers consist of the thermoplastic first polymer
material including a thermoplastic first base polymer and the second component of the
2
multicomponent fibers consist of the thermoplastic second polymer material including a
thermoplastic second base polymer different from the first base polymer, at least one of the first
polymer material or the second polymer material is a polymer blend further including, in addition
to each base polymer, a high melt flow rate polymer of 1 % to 10 % by weight, a melt flow rate of
the high melt flow rate polymer is from 600 g/10 min to 3000 g/10 min under the conditions of
230°C and 2.16 kg, the multicomponent fibers have a linear mass density of less than 1.5 denier,
and the average number of crimps of the multicomponent fibers is in the range of at least 5 per 1
cm of fiber (for example, see Patent Document 2).
Citation List
Patent Document
[0005] [Patent Document 1] Japanese Patent Application Laid-Open (JP-A) No. 2019-131945
[Patent Document 2] JP-A No. 2019-131946
SUMMARY OF INVENTION
[0006] It is difficult to provide a spunbond nonwoven fabric layered body with good bulkiness,
flexibility and uniformity. The spunbond nonwoven fabric layered body described in Patent
Document 1 is excellent in bulkiness, but there is room for improvement in terms of uniformity.
Further, the spunbond nonwoven fabric described in Patent Document 2 has improved uniformity
and flexibility, but there is room for improvement in terms of bulkiness, and there is room for
further improvement in terms of uniformity.
[0007] The invention is made in view of the above, and the object is to provide a nonwoven
fabric layered body excellent in bulkiness, flexibility and uniformity and a cover sheet and an
absorbent article that include the nonwoven fabric layered body.
Solution to Problem
[0008] Means for solving the above problems include the following aspect.
<1> A nonwoven fabric layered body including, in the following order:
a crimped surface layer including a crimped spunbond nonwoven fabric including a
crimped fiber,
a crimped intermediate layer including a crimped spunbond nonwoven fabric including a
3
crimped fiber, and
a non-crimped surface layer including a non-crimped spunbond nonwoven fabric
including a non-crimped fiber,
in which a linear mass density of the crimped fiber in the crimped surface layer is from
1.4 denier to 1.6 denier, and
a linear mass density of the crimped fiber in the crimped intermediate layer is less than 1.4
denier.
<2> The nonwoven fabric layered body according to <1>, in which the linear mass density of
the crimped fiber in the crimped surface layer is from 1.5 denier to 1.6 denier.
<3> The nonwoven fabric layered body according to <1> or <2>, in which the linear mass
density of the crimped fiber in the crimped intermediate layer is from 0.7 denier to 1.3 denier.
<4> The nonwoven fabric layered body according to any one of <1> to <3>, in which a linear
mass density of the non-crimped fiber in the non-crimped surface layer is 1.3 denier or less.
<5> The nonwoven fabric layered body according to any one of <1> to <4>, in which each of
the crimped fiber in the crimped surface layer and the crimped fiber in the crimped intermediate
layer includes a propylene-based polymer.
<6> The nonwoven fabric layered body according to any one of <1> to <5>, in which each
melt flow rate (MFR) (ASTM D-1238, 230°C, and load: 2,160 g) of a thermoplastic resin included
in the crimped fiber in the crimped surface layer and a thermoplastic resin included in the crimped
fiber in the crimped intermediate layer is independently 100 g/10 min or less.
<7> The nonwoven fabric layered body according to any one of <1> to <6>, in which a total
basis weight of the nonwoven fabric layered body is from 15 g/m2
to 20 g/m2
.
<8> The nonwoven fabric layered body according to any one of <1> to <7>, in which a total
value of a basis weight of the crimped surface layer and the crimped intermediate layer is 50 % or
more with respect to a total basis weight of the nonwoven fabric layered body.
<9> The nonwoven fabric layered body according to any one of <1> to <8>, in which in each
layer of the nonwoven fabric layered body, a ratio (maximum basis weight/minimum basis weight)
of a basis weight (maximum basis weight) in a layer with a maximum basis weight and a basis
4
weight (minimum basis weight) in a layer with a minimum basis weight is from 1.0 to 1.3.
<10> A nonwoven fabric layered body including:
a crimped layer including a crimped spunbond nonwoven fabric including a crimped fiber,
and
a non-crimped surface layer including a non-crimped spunbond nonwoven fabric
including a non-crimped fiber,
in which the nonwoven fabric layered body satisfies the following (1) to (3):
(1) a difference (TO - TM) between a thickness TO at pressure of 0.5 gf/cm2
in a compression
characteristics test measured by a KES method and a thickness TM at pressure of 50 gf/cm2
measured by the KES method is more than 0.30 mm;
(2) a value of a cantilever in an MD direction in accordance with a cantilever method (ISO
method) of JIS L 1913: 2010 is less than 40 mm; and
(3) a formation index (V) represented by the following Formula (a) is less than 310:
Formula (a): V = 10σ/E
in which, in Formula (a), V represents the formation index, σ represents a standard
deviation of a shading unevenness of the nonwoven fabric layered body, E represents 2-logT, and
T represents a light transmittance (%) of the nonwoven fabric layered body.
<11> A cover sheet including the nonwoven fabric layered body according to any one of <1> to
<10>.
<12> An absorbent article including the nonwoven fabric layered body according to any one of
<1> to <10> and the cover sheet according to <11>.
Advantageous Effects of Invention
[0009] According to the present disclosure, a nonwoven fabric layered body excellent in
bulkiness, flexibility and uniformity and a cover sheet and an absorbent article that include the
nonwoven fabric layered body can be provided.
DESCRIPTION OF EMBODIMENTS
[0010] In the present disclosure, numerical ranges indicated using "to" mean a range including
the numerical values described before and after "to" as the lower limit value and the upper limit
5
value, respectively.
In a set of numerical ranges that are stated stepwise in the present disclosure, the upper
limit value or the lower limit value of a numerical range may be replaced with an upper limit value
or a lower limit value of other numerical range. Further, in a numerical range stated in the present
disclosure, the upper limit or the lower limit of the numerical range may be replaced with a
relevant value indicated in any of Examples.
In the present disclosure, the "step" refers not only to a step that is independent from the
other steps, but also to a step that cannot be clearly distinguished from the other steps, as long as
the aim of the step is achieved.
In the present disclosure, when referring to the amount of each component in the
composition, in a case in which there are plural substances corresponding to each component in the
composition, it refers to the total amount of the plural substances in the composition, unless
otherwise specified.
[0011] [Nonwoven Fabric Layered Body]

A nonwoven fabric layered body according to a first embodiment of the present disclosure
includes, in the following order: a crimped surface layer including a crimped spunbond nonwoven
fabric including a crimped fiber, a crimped intermediate layer including a crimped spunbond
nonwoven fabric including a crimped fiber, and a non-crimped surface layer including a noncrimped spunbond nonwoven fabric including a non-crimped fiber, in which a linear mass density
of the crimped fiber in the crimped surface layer is from 1.4 denier to 1.6 denier, and a linear mass
density of the crimped fiber in the crimped intermediate layer is less than 1.4 denier.
[0012] The nonwoven fabric layered body of the present embodiment is excellent in bulkiness,
flexibility and uniformity. The reason is presumed as follows. The nonwoven fabric layered body
of the present embodiment includes the crimped surface layer in which the linear mass density of
the crimped fiber is from 1.4 denier to 1.6 denier, and the crimped intermediate layer in which the
linear mass density of the crimped fiber is less than 1.4 denier, and thereby the nonwoven fabric
layered body is excellent in bulkiness, flexibility and uniformity. Especially, the nonwoven fabric
6
layered body of the present embodiment is provided with the crimped intermediate layer, and
thereby the nonwoven fabric layered body is superior in the bulkiness to a nonwoven fabric layer
with a non-crimped intermediate layer and without a crimped intermediate layer. Further, in the
crimped intermediate layer, due to the configuration that the linear mass density of the crimped
fiber is less than 1.4 denier, the crimped fiber can be made thin, and the amount of the fiber in the
crimped intermediate layer can be increased at the same basis weight. Thereby, the configuration
contributes to the uniformity of the nonwoven fabric layered body. The nonwoven fabric layered
body of the present embodiment includes the crimped surface layer in which the linear mass
density of the crimped fiber is from 1.4 denier to 1.6 denier, and thereby the bulkiness can be
improved as compared with the case where a nonwoven fabric layered body includes a crimped
surface layer in which the linear mass density of the crimped fiber is less than 1,4 denier, and the
uniformity can be improved as compared with the case in which a nonwoven fabric layered body
includes a crimped surface layer in which the linear mass density of the crimped fiber is more than
1.6 denier.
[0013] Further, the nonwoven fabric layered body of the present embodiment is excellent in fuzz
resistance. The reason is presumed that the nonwoven fabric layered body of the present
embodiment includes the non-crimped surface layer including the non-crimped spunbond
nonwoven fabric, and the non-crimped surface layer is less fuzzy than a crimped surface layer.
[0014] Hereinafter, the configurations of the crimped surface layer, the crimped intermediate
layer and the non-crimped surface layer included in the nonwoven fabric layered body of the
present embodiment will be explained.
[0015] (Crimped Surface Layer)
The nonwoven fabric layered body of the present embodiment includes a crimped surface
layer including a crimped spunbond nonwoven fabric including a crimped fiber, and the linear
mass density of the crimped fiber in the crimped surface layer is from 1.4 denier to 1.6 denier.
[0016] The crimped surface layer may have one layer or may have two or more layers. When the
crimped surface layer has two or more layers, in each of the two or more layers, the linear mass
density of the crimped fiber only has to satisfy from 1.4 denier to 1.6 denier.
7
[0017] The linear mass density of the crimped fiber in the crimped surface layer is preferably
from 1.5 denier to 1.6 denier, from the view point of the bulkiness and uniformity of the nonwoven
fabric layered body.
[0018] The crimped fiber in the crimped surface layer preferably includes a thermoplastic resin.
The thermoplastic resin is not particularly limited as long as it is possible to produce a crimped
spunbond nonwoven fabric including a crimped fiber, and examples thereof include olefin-based
polymers, polyester-based polymers, polyamide-based polymers, thermoplastic resin compositions
including a plurality of these polymers, and the like. In the present disclosure, the thermoplastic
resin is a concept including the thermoplastic resin composition.
[0019] The melt flow rate (MFR) (ASTM D-1238, 230°C, a load of 2160 g) of the thermoplastic
resin is preferably 100 g/10 min or less, more preferably from 20 g/10 min to 100 g/10 min, and
still more preferably from 30 g/10 min to 80 g/10 min. When the MFR of the thermoplastic resin
is 100 g/10 min or less, the crimped fiber tends to have excellent mechanical strength. When the
MFR of the thermoplastic resin is 20 g/10 min or more, fiber breakage during draw spinning tends
to be reduced.
[0020] The olefin-based polymers is a polymer mainly including a structural unit derived from an
olefin, the polyester-based polymer is a polymer including a polyester as a structural unit, and the
polyamide-based polymer is a polymer including a polyamide as a structural unit.
In the present disclosure, "mainly including" means that the target substance is included in
the largest amount in the total. For example, it means that as a ratio with respect to the total, the
content ratio of the target substance is 50 % by mass or more.
[0021] The thermoplastic resin preferably includes the olefin-based polymer. Examples of the
olefin-based polymers include homopolymers or copolymers of α-olefin(s) such as ethylene,
propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-
ethyl-1-pentene , 4-methyl-1-pentene, 4-methyl-1-hexene, or the like.
[0022] More specifically, examples of the α-olefin homopolymers or copolymers include
ethylene-based polymers such as a high-pressure low-density polyethylene, a linear low-density
polyethylene (LLDPE), a high-density polyethylene, and an ethylene/α-olefin copolymer including
8
a structural unit derived from ethylene as a main parts, propylene-based polymers such as
polypropylene (propylene homopolymer), and a propylene/α-olefin copolymer including a
structural unit derived from propylene as a main parts, 1-butene-based polymers such as a 1-butene
homopolymer, and a 1-butene/α-olefin copolymer including a structural unit derived from 1-butene
as a main parts, 4-methyl-1-pentene-based polymers such as a 4-methyl-1-pentene homopolymer,
and a 4-methyl-1-pentene/α-olefin copolymer including a structural unit derived from 4-methyl-1-
pentene as a main parts. Among them, from the viewpoint of being excellent in spinnability,
mechanical strength, chemical resistance and the like, the α-olefin homopolymer or copolymer is
preferably the propylene-based polymer.
[0023] The propylene-based polymer may be either a propylene homopolymer or a propylene/αolefin copolymer, or may include both. The α-olefin used for the copolymerization of the
propylene/α-olefin copolymer is preferably an α-olefin having 2 or more carbon atoms (excluding
propylene), more preferably an α-olefin having 2 or 4 to 8 carbon atoms. Specifically, the α-olefin
is preferably ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-butene, 3-methyl-1-
pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene or the like.
[0024] More specifically, examples of the propylene/α-olefin copolymer include a
propylene/ethylene copolymer, and a propylene/ethylene/1-butene copolymer.
[0025] In the propylene/α-olefin copolymer, the content ratio of the structural unit derived from
the α-olefin is preferably from 1 mol% to 10 mol% of the total and more preferably from 1 mol%
to 5 mol% of the total.
[0026] The melting point (Tm) of the propylene-based polymer is preferably 120°C or more, and
more preferably from 125°C to 165°C.
In the present disclosure, the melting point is measured as follows.
(1) The propylene-based polymer is placed in a measurement pan of a differential scanning
calorimeter (DSC) manufactured by PerkinElmer, the temperature is raised from 30°C to 200°C at
a rate of 10°C/min, held at 200°C for 10 minutes, and then, lowered to 30°C at a rate of 10°C/min.
(2) Next, the temperature is again raised from 30°C to 200°C at a rate of 10° C/min, and the
melting point is determined from the peak observed during that time.
9
[0027] The melting point (Tm) of the propylene homopolymer is preferably 155°C or more, and
more preferably from 157°C to 165°C.
The melting point (Tm) of the propylene/α-olefin copolymer is preferably from 120°C to
155 °C, and more preferably from 125°C to 150°C.
[0028] The melt flow rate (MFR) (ASTM D1238, 230°C, and load: 2,160 g) of the propylenebased polymer is preferably from 20 g/10 min to 100 g/10 min, and more preferably from 30 g/10
min to 80 g/10 min. When the MFR of the propylene-based polymer is 100 g/10 min or less, there
is a tendency that the crimped fiber has excellent mechanical strength. When the MFR of the
propylene-based polymer is 20 g/10 min or more, there is a tendency that fiber breakage during
draw spinning can be reduced.
[0029] The crimped fiber in the crimped surface layer may be a fiber including one kind of a
thermoplastic resin, or may be composite fiber including two or more kinds of thermoplastic
resins. The composite fiber may be, for example, a side-by-side type, a concentric core sheath type
or an eccentric core sheath type. The eccentric core sheath type composite fiber may be an
exposed type in which the core portion is exposed at the surface, or a non-exposed type in which
the core portion is not exposed at the surface.
[0030] When the composite fiber is a core sheath type, the mass ratio (core portion/sheath
portion) of the sheath portion and the core portion is, for example, preferably from 95/5 to 5/95,
more preferably from 90/10 to 10/90, and further preferably from 60/40 to 10/90.
[0031] The crimped fiber in the crimped surface layer is preferably composite fiber including the
propylene-based polymer, more preferably crimped composite fiber including the propylene-based
polymer, and still more preferably eccentric core sheath type crimped composite fiber including
the propylene-based polymer.
[0032] When the crimped fiber in the crimped surface layer is the composite fiber including the
propylene-based polymer, a composite fiber including two or more kinds of propylene-based
polymers are preferable. When the composite fiber is the core sheath type, it is preferable that the
core portion and the sheath portion each include one or more propylene-based polymers. The
propylene-based polymer included in the core portion is preferably a propylene homopolymer (A)
10
having a melting point (Tm) of 155°C or more, and preferably a propylene homopolymer (A)
having a melting point (Tm) of 157°C to 165°C. The propylene-based polymer included in the
sheath portion is preferably a propylene/α-olefin copolymer (B) having a melting point (Tm) of
120°C to 155°C, and preferably a propylene/α-olefin copolymer (B) having a melting point (Tm)
of 125°C to 150°C.
[0033] The propylene-based polymer such as the propylene homopolymer (A), the propylene/αolefin copolymer (B) and the like can be obtained by homopolymerization of propylene, or
copolymerization of propylene and a small amount of any α-olefin, according to slurry
polymerization, gas-phase polymerization, or bulk polymerization by use of a so-called ZieglerNatta catalyst as a combination of a titanium-containing solid transition metal component and an
organometallic component, or a metallocene catalyst including a compound of any transition metal
belonging to the Groups 4 to 6 in the periodic table, the compound having at least one
cyclopentadiene backbone, and a co-catalyst component.
[0034] A commercially available product may be used as the propylene homopolymer (A). For
example, a propylene-based polymer manufactured by Prime Polymer Co., Ltd. under the trade
name Prime Polypro S119 may be used.
[0035] A commercially available product may be used as the propylene/α-olefin copolymer (B).
For example, a propylene-based polymer manufactured by Prime Polymer Co., Ltd. under the trade
name Prime Polypro S229R may be used.
[0036] The basis weight of the crimped surface layer is not particularly limited, and for example,
is preferably from 2 g/m2
to 10 g/m2
, and more preferably from 3 g/m2
to 8 g/m2
.
The method for measuring the basis weight in the present disclosure is as described in
Example below.
[0037] (Crimped Intermediate Layer)
The nonwoven fabric layered body of the present embodiment includes a crimped
intermediate layer including a crimped spunbond nonwoven fabric including a crimped fiber, and
the linear mass density of the crimped fiber in the crimped intermediate layer is less than 1.4
denier.
11
[0038] The crimped intermediate layer may have one layer or may have two or more layers.
When the crimped intermediate layer has two or more layers, in each of the two or more layers, the
linear mass density of the crimped fiber only has to satisfy less than 1.4 denier.
[0039] The linear mass density of the crimped fiber in the crimped intermediate layer is
preferably 1.3 denier or less, more preferably from 0.7 denier to 1.3 denier, and still more
preferably from 1.0 denier to 1.3 denier, from the view point of the bulkiness and uniformity of the
nonwoven fabric layered body.
[0040] The crimped fiber in the crimped intermediate layer preferably includes a thermoplastic
resin. Examples of the thermoplastic resin include the thermoplastic resin that may be included in
the crimped fiber in the afore-mentioned crimped surface layer.
[0041] The crimped fiber in the crimped intermediate layer may be a fiber including one kind of a
thermoplastic resin, or may be a composite fiber including two or more kinds of thermoplastic
resins. When the crimped fiber in the crimped intermediate layer is a composite fiber, a preferred
form is the same as the afore-mentioned crimped surface layer.
[0042] The basis weight of the crimped intermediate layer is not particularly limited, and for
example, is preferably from 2 g/m2
to 10 g/m2
, and more preferably from 3 g/m2
to 8 g/m2
.
[0043] In the nonwoven fabric layered body of the present embodiment, the linear mass density
of the crimped fiber in the crimped surface layer is from 1.4 denier to 1.6 denier, and the linear
mass density of the crimped fiber in the crimped intermediate layer is less than 1.4 denier. Thus,
the crimping degree of the crimped intermediate layer tends to be greater than that of the crimped
surface layer.
In the present disclosure, the crimping degree means the degree of crimping of fiber, and a
large crimping degree means that the degree of crimping of fiber is large. Whether the crimping
degree is large or small can be confirmed, for example, by observing the cross section of the
nonwoven fabric layered body using a scanning electron microscope or the like and comparing the
crimp shapes of the fiber on the surface and inside of the nonwoven fabric layered body.
[0044] (Non-crimped Surface Layer)
The nonwoven fabric layered body of the present embodiment includes a non-crimped
12
surface layer including a non-crimped spunbond nonwoven fabric including a non-crimped fiber.
The non-crimped surface layer may have one layer or may have two or more layers.
[0045] The linear mass density of the non-crimped fiber in the non-crimped surface layer is
preferably 1.3 denier or less, and more preferably from 1.0 denier to 1.3 denier. When the linear
mass density of the non-crimped fiber is 1.3 denier or less, there is a tendency that the non-crimped
fiber has excellent mechanical strength and uniformity. When the linear mass density of the noncrimped fiber is 1.0 denier or more, there is a tendency that the non-crimped fiber has excellent
mechanical strength.
[0046] The non-crimped fiber in the non-crimped surface layer preferably includes a
thermoplastic resin. Examples of the thermoplastic resin include the thermoplastic resin that may
be included in the crimped fiber in the afore-mentioned crimped surface layer.
[0047] The thermoplastic resin that may be included in the non-crimped fiber in the non-crimped
surface layer is preferably the afore-mentioned olefin-based polymer, and more preferably the
propylene-based polymer.
[0048] The basis weight of the non-crimped surface layer is not particularly limited, and for
example, is preferably from 2 g/m2
to 10 g/m2
, and more preferably from 3 g/m2
to 8 g/m2
.
[0049] The crimped fiber in the crimped surface layer and the crimped intermediate layer and the
non-crimped fiber in the non-crimped surface layer may include an additive used in the production
of a nonwoven fabric. Examples of the additive include various known additives such as a
hydrophilizing agent, an antioxidant, a weather-resistant stabilizer, a heat-resistant stabilizer, a
light-resistant stabilizer, an antistatic agent, an antifogging agent, a lubricant, a dye, a pigment, a
natural oil, a synthetic oil, and a wax.
[0050] The nonwoven fabric layered body of the present embodiment includes another nonwoven
fabric layer between the crimped surface layer and the crimped intermediate layer, between the
crimped intermediate layer and the non-crimped surface layer, outside the crimped surface layer,
outside the non-crimped surface layer or the like, and preferably includes another nonwoven fabric
layer between the crimped surface layer and the crimped intermediate layer, between the crimped
intermediate layer and the non-crimped surface layer, or outside the crimped surface layer.
13
Examples of the nonwoven fabric constituting another nonwoven fabric layer include various
known nonwoven fabrics such as a spunbond nonwoven fabric, a meltblown nonwoven fabric, a
wet nonwoven fabric, a dry nonwoven fabric, a dry pulp nonwoven fabric, a flash spun nonwoven
fabric, and an open fiber nonwoven fabric. When the nonwoven fabric constituting another
nonwoven fabric layer is a spunbond nonwoven fabric, this spunbond nonwoven fabric is not
particularly limited as long as it is other than the crimped spunbond nonwoven fabric in the
crimped surface layer, the crimped spunbond nonwoven fabric in the crimped intermediate layer,
or the non-crimped spunbond nonwoven fabric in the non-crimped surface layer.
[0051] The nonwoven fabric layer constituting another nonwoven fabric layer may be a
meltblown nonwoven fabric. For example, the nonwoven fabric layered body of the present
embodiment includes a meltblown nonwoven fabric layer including the meltblown nonwoven
fabric between the crimped surface layer and the crimped intermediate layer, between the crimped
intermediate layer and the non-crimped surface layer or outside the crimped surface layer.
[0052] Another layer such as another nonwoven fabric layer mentioned above, a knitted fabric, a
woven fabric, a film or the like may be stacked on the nonwoven fabric layered body of the present
embodiment. When the nonwoven fabric layer and another layer are stacked, various known
methods such as thermal fusion methods such as thermal embossing and ultrasonic fusion,
mechanical entanglement methods such as needle punching and water jets, methods with adhesives
such as hot melt adhesives or urethane adhesives, and extrusion lamination can be adopted.
[0053] In the nonwoven fabric layered body of the present embodiment, the total basis weight of
the nonwoven fabric layered body is preferably from 10 g/m2
to 30 g/m2
, and more preferably from
15 g/m2
to 20 g/m2
, from the viewpoint of balance of mechanical strength, flexibility, bulkiness
and uniformity, when the total basis weight of the nonwoven fabric layered body is 30 g/m2
or less,
there is a tendency that the nonwoven fabric layered body is excellent in flexibility. When the
total basis weight of the nonwoven fabric layered body is 10 g/m2
or more, there is a tendency that
the nonwoven fabric layered body is excellent in mechanical strength, bulkiness and uniformity.
Further, when trying to reduce the basis weight of the nonwoven fabric layered body, the
bulkiness, uniformity, or the like tend to be impaired, while the nonwoven fabric layered body of
14
the present embodiment can improve the bulkiness and uniformity. Thus, it is easy to achieve both
the low basis weight and excellent bulkiness and uniformity in the nonwoven fabric layered body.
[0054] In nonwoven fabric layered body of the present embodiment, from the viewpoint of
balance of mechanical strength, flexibility, bulkiness and uniformity, the total value of the basis
weight of the crimped surface layer and the crimped intermediate layer is preferably 50 % or more,
and more preferably from 60 % to 75 %, with respect to the total basis weight of the nonwoven
fabric layered body. When the afore-mentioned ratio of the total value is 75 % or less, there is a
tendency that the nonwoven fabric layered body is excellent in mechanical strength and
uniformity. When the afore-mentioned ratio of the total value is 50 % or more, there is a tendency
that the nonwoven fabric layered body is excellent in flexibility and bulkiness.
[0055] In nonwoven fabric layered body of the present embodiment, from the viewpoint of
balance of flexibility, bulkiness and uniformity, the total value of the basis weight of the crimped
surface layer, the crimped intermediate layer and the non-crimped surface layer is preferably from
60 % to 100 %, and more preferably from 80 % to 100 %, with respect to the total basis weight of
the nonwoven fabric layered body.
[0056] In each of the layers included in the nonwoven fabric layered body of the present
embodiment, a ratio (maximum basis weight/minimum basis weight) of the basis weight
(maximum basis weight) in the layer with the largest basis weight and the basis weight (minimum
basis weight) in the layer with the smallest basis weight is preferably from 1.0 to 1.3, and more
preferably from 1.1 to 1.3.
[0057] In the nonwoven fabric layered body of the present embodiment, the ratio (basis weight of
crimped surface layer/basis weight of crimped intermediate layer) of the basis weight of the
crimped surface layer and the basis weight of the crimped intermediate layer is preferably from 0.5
to 1.5, and more preferably from 0.7 to 1.3, from the viewpoint of a balance of flexibility,
bulkiness and uniformity.
[0058] A method of manufacturing the nonwoven fabric layered body of the present disclosure is
not particularly limited.
For example, the nonwoven fabric layered body of the present disclosure can be
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manufactured by the following manufacturing method 1 and manufacturing method 2.
[0059] (Manufacturing Method 1 of Nonwoven Fabric Layered Body)
The manufacturing method 1 includes a step of producing the crimped surface layer
including the crimped spunbond nonwoven fabric by melt-spinning a thermoplastic resin by a
spunbond method and depositing crimped fiber obtained by melt-spinning on a moving collecting
surface,
a step of producing the crimped intermediate layer including the crimped spunbond
nonwoven fabric by melt-spinning a thermoplastic resin by a spunbond method and depositing
crimped fiber obtained by melt-spinning on the crimped surface layer on the moving collecting
surface, and
a step of producing the non-crimped surface layer including the non-crimped spunbond
nonwoven fabric by melt-spinning a thermoplastic resin by a spunbond method and depositing
non-crimped fiber obtained by melt-spinning on the crimped intermediate layer.
[0060] In the step of producing the crimped surface layer and the step of producing the crimped
intermediate layer, the crimped fiber may be obtained by melting thermoplastic resins individually
using at least two extruders and discharging two or more thermoplastic resins from a composite
spinning nozzle to perform composite melt spinning.
[0061] In the step of producing the crimping surface layer and the step of producing the crimped
intermediate layer, the linear mass density of the crimped fiber in the crimped surface layer and the
linear mass density of the crimped fiber in the crimped intermediate layer can be adjusted by
appropriately adjusting the amount of air, the diameter of the spinning nozzle, and the amount of
discharge from the spinning nozzle during melt spinning by the spunbond method.

CLAIMS
1. A nonwoven fabric layered body comprising, in the following order:
a crimped surface layer including a crimped spunbond nonwoven fabric including a
crimped fiber,
a crimped intermediate layer including a crimped spunbond nonwoven fabric including a
crimped fiber, and
a non-crimped surface layer including a non-crimped spunbond nonwoven fabric
including a non-crimped fiber,
wherein a linear mass density of the crimped fiber in the crimped surface layer is from 1.4
denier to 1.6 denier, and
a linear mass density of the crimped fiber in the crimped intermediate layer is less than 1.4
denier.
2. The nonwoven fabric layered body according to claim 1, wherein the linear mass density
of the crimped fiber in the crimped surface layer is from 1.5 denier to 1.6 denier.
3. The nonwoven fabric layered body according to claim 1 or claim 2, wherein the linear
mass density of the crimped fiber in the crimped intermediate layer is from 0.7 denier to 1.3
denier.
4. The nonwoven fabric layered body according to any one of claims 1 to 3, wherein a linear
mass density of the non-crimped fiber in the non-crimped surface layer is 1.3 denier or less.
5. The nonwoven fabric layered body according to any one of claims 1 to 4, wherein each of
the crimped fiber in the crimped surface layer and the crimped fiber in the crimped intermediate
layer includes a propylene-based
polymer.
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6. The nonwoven fabric layered body according to any one of claims 1 to 5, wherein each
melt flow rate (MFR) (ASTM D-1238, 230°C, and load: 2,160 g) of a thermoplastic resin included
in the crimped fiber in the crimped surface layer and a thermoplastic resin included in the crimped
fiber in the crimped intermediate layer is independently 100 g/10 min or less.
7. The nonwoven fabric layered body according to any one of claims 1 to 6, wherein a total
basis weight of the nonwoven fabric layered body is from 15 g/m2
to 20 g/m2
.
8. The nonwoven fabric layered body according to any one of claims 1 to 7, wherein a total
value of a basis weight of the crimped surface layer and the crimped intermediate layer is 50 % or
more with respect to a total basis weight of the nonwoven fabric layered body.
9. The nonwoven fabric layered body according to any one of claims 1 to 8, wherein in each
layer of the nonwoven fabric layered body, a ratio (maximum basis weight/minimum basis weight)
of a basis weight (maximum basis weight) in a layer with a maximum basis weight and a basis
weight (minimum basis weight) in a layer with a minimum basis weight is from 1.0 to 1.3.
10. A nonwoven fabric layered body comprising:
a crimped layer including a crimped spunbond nonwoven fabric including a crimped fiber,
and
a non-crimped surface layer including a non-crimped spunbond nonwoven fabric
including a non-crimped fiber,
wherein the nonwoven fabric layered body satisfies the following (1) to (3):
(1) a difference (TO - TM) between a thickness TO at pressure of 0.5 gf/cm2
in a compression
characteristics test measured by a KES method and a thickness TM at pressure of 50 gf/cm2
measured by the KES method is more than 0.30 mm;
(2) a value of a cantilever in an MD direction in accordance with a cantilever method (ISO
32
method) of JIS L 1913: 2010 is less than 40 mm; and
(3) a formation index (V) represented by the following Formula (a) is less than 310:
Formula (a): V = 10σ/E
wherein, in Formula (a), V represents the formation index, σ represents a standard
deviation of a shading unevenness of the nonwoven fabric layered body, E represents 2-logT, and
T represents a light transmittance (%) of the nonwoven fabric layered body.
11. A cover sheet comprising the nonwoven fabric layered body according to any one of
claims 1 to 10.
12. An absorbent article comprising the nonwoven fabric layered body according to any one
of claims 1 to 10 and the cover sheet according to claim 11.