TITLE OF THE INVENTION:
LAMINATE SHEET, SANITARY MATERIAL, MEDICAL MATERIAL, AND METHOD
FOR MANUFACTURING LAMINATE SHEET
[0001]
The present invention relates to a laminate sheet, a sanitary material, a medical material,
and a method for manufacturing a laminate sheet.
BACKGROUND ART
[0002]
Sanitary materials such as paper diapers are required to suppress the passing of liquid
water and to have excellent stretchability and excellent water-vapor permeability. It has been
considered to use a laminate sheet of a water-vapor permeable polyurethane film and a
stretchable nonwoven fabric laminated on the film for such sanitary materials.
[0003]
As such a laminate sheet, for example, a stretchable, water-vapor permeable, waterproof sheet has been proposed (for example, Patent document 1 (Example 1) below). The sheet
includes a water-vapor permeable polyurethane film formed of a polyurethane resin and a
nonwoven fabric made of polypropylene, where the polyurethane resin is a reaction product of
an oxyalkylene polyol, 1,4-butanediol that is a chain extender, and diphenylmethane
diisocyanate; the oxyalkylene polyol is obtained by the addition polymerization of 90% by
weight of ethylene oxide and 10% by weight of propylene oxide; and the nonwoven fabric is
laminated on the water-vapor permeable polyurethane film.
Citation List
Patent Document
[0004]
Patent Document 1: Japanese Unexamined Patent Publication No. H7-70936
SUMMARY OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
[0005]
2
However, there is a limit to the improvement of the stretchability of the stretchable
water-vapor permeable sheet of Patent Document 1. Further, the nonwoven fabric of the
stretchable water-vapor permeable sheet of Patent Document 1 has insufficient adhesion to the
water-vapor permeable polyurethane film. Thus, the nonwoven fabric may peel from the watervapor permeable polyurethane film. Furthermore, the reduction in tackiness properties
(stickiness) of the laminate sheet is required in view of the feel of the sheet when the laminate
sheet is in contact with a human body.
[0006]
In light of the foregoing, the present invention provides a laminate sheet, a sanitary
material, a medical material, and a method for manufacturing a laminate sheet that can improve
the stretchability and the adhesion of the spunbond nonwoven fabric to the water-vapor
permeable polyurethane film, and can reduce the tackiness properties.
MEANS FOR SOLVING THE PROBLEM
[0007]
The present invention [1] includes a laminate sheet comprising: a water-vapor
permeable polyurethane film having a hard segment phase; and a first spunbond nonwoven
fabric disposed at one side in a thickness direction of the water-vapor permeable polyurethane
film, the first spunbond nonwoven fabric containing stretchable fibers containing a thermoplastic
polyurethane and non-stretchable fibers containing a polyolefin, wherein the hard segment phase
has a melting point of 65℃ or more and 140℃ or less.
[0008]
The present invention [2] includes the laminate sheet described in [1], wherein the
water-vapor permeable polyurethane film has a soft segment phase, and the soft segment phase is
formed by a reaction of a polyether polyol and a polyisocyanate.
[0009]
The present invention [3] includes the laminate sheet described in [2], wherein the
polyether polyol has a number average molecular weight of 1200 g/mol or more and 2800 g/mol
or less.
[0010]
3
The present invention [4] includes the laminate sheet described in any one of the abovedescribed [1] to [3], further comprising: a second spunbond nonwoven fabric disposed at the
other side in the thickness direction of the water-vapor permeable polyurethane film, the second
spunbond nonwoven fabric containing stretchable fibers containing a thermoplastic polyurethane
and non-stretchable fibers containing a polyolefin.
[0011]
The present invention [5] includes the laminate sheet described in any one of the abovedescribed [1] to [3], wherein the first spunbond nonwoven fabric is in direct contact with a oneside surface in the thickness direction of the water-vapor permeable polyurethane film.
[0012]
The present invention [6] includes a sanitary material comprising the laminate sheet
described in [1].
[0013]
The present invention [7] includes a medical material comprising the laminate sheet
described in [1].
[0014]
The present invention [8] includes a method for manufacturing a laminate sheet, the
method comprising: a step of mixing and joining stretchable fibers containing a thermoplastic
polyurethane and non-stretchable fibers containing a polyolefin by heat fusion to prepare a
spunbond nonwoven fabric; a step of preparing a water-vapor permeable polyurethane film
having a hard segment phase, the hard segment phase having a melting point of 65℃ or more
and 140℃ or less; a step of applying pressure on the spunbond nonwoven fabric against the
water-vapor permeable polyurethane film to laminate the spunbond nonwoven fabric and the
water-vapor permeable polyurethane film; and a step of subjecting the spunbond nonwoven
fabric to a stretching process before the laminating step; and/or a step of subjecting the laminated
spunbond nonwoven fabric and water-vapor permeable polyurethane film to a stretching process
after the laminating step.
[0015]
The present invention [9] includes the method described in [8], wherein the spunbond
nonwoven fabric is in direct contact with a one-side surface in a thickness direction of the water-
4
vapor permeable polyurethane film in the step of laminating the spunbond nonwoven fabric and
the water-vapor permeable polyurethane film.
EFFECTS OF THE INVENTION
[0016]
In the laminate sheet of the present invention, the melting point of the hard segment
phase of the water-vapor permeable polyurethane film is the above-described upper limit or less,
and the first spunbond nonwoven fabric includes the stretchable fibers containing a thermoplastic
polyurethane. Thus, the stretchability of the laminate sheet can be improved while the adhesion
of the first spunbond nonwoven fabric to the water-vapor permeable polyurethane film can be
improved. Further, the melting point of the hard segment phase of the water-vapor permeable
polyurethane film is the above-described lower limit or more, and the first spunbond nonwoven
fabric includes the non-stretchable fibers containing a polyolefin. Thus, the tackiness
properties of the laminate sheet can be reduced.
[0017]
The method of manufacturing a laminate sheet of the present invention includes the step
of subjecting the spunbond nonwoven fabric to a stretching process before the laminating of the
spunbond nonwoven fabric and the water-vapor permeable polyurethane film and/or the step of
subjecting the spunbond nonwoven fabric and water-vapor permeable polyurethane film to a
stretching process after the laminating step, and thus can smoothly manufacture laminate sheets
having the above-described properties.
[0018]
The sanitary material and medical material of the present invention include the abovedescribed laminate sheet, and thus can ensure excellent stretchability and excellent adhesion
while simultaneously reducing the tackiness properties.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019]
FIG. 1 is a schematic view of one embodiment of the laminate sheet of the present
invention.
FIG. 2 is a schematic view of a melt extrusion laminator that can implement the method
for manufacturing a laminate sheet of the present invention.
5
DESCRIPTION OF THE EMBODIMENTS
[0020]

With reference to FIG. 1 and FIG. 2, a laminate sheet 1 is described as one embodiment
of the laminate sheet of the present invention.
[0021]
As illustrated in FIG. 1, the laminate sheet 1 includes a water-vapor permeable
polyurethane film 2, a first spunbond nonwoven fabric 3, and a second spunbond nonwoven
fabric 4.
[0022]
The water-vapor permeable polyurethane film 2 has a film shape (flat board shape).
Specifically, the water-vapor permeable polyurethane film 2 has a predetermined thickness,
extends in a predetermined direction orthogonal to the thickness direction, and has a flat front
surface and a flat back surface.
[0023]
The thickness of the water-vapor permeable polyurethane film 2 is, for example, 1 μm
or more, preferably 5 μm or more, more preferably 10 μm or more, and, for example, 50 μm or
less, preferably 30 μm or less, more preferably 25 μm or less.
[0024]
The water-vapor permeable polyurethane film 2 contains a water-vapor permeable
polyurethane resin, and preferably consists of a water-vapor permeable polyurethane resin. The
water-vapor permeable polyurethane film 2 has a hard segment phase and a soft segment phase.
[0025]
The hard segment phase is a region (domain) made of a polyisocyanate and a low
molecular-weight diol that is a chain extender, and is formed by a reaction of the polyisocyanate
and the low molecular-weight diol.
[0026]
The polyisocyanate contains, for example, diphenylmethane diisocyanate (MDI).
[0027]
6
Examples of the diphenylmethane diisocyanate include 4,4’-diphenylmethane
diisocyanate, 2,4’-diphenylmethane diisocyanate, and 2,2’-diphenylmethane diisocyanate.
[0028]
The diphenylmethane diisocyanates can be used singly or in combination of two or
more.
[0029]
Among the diphenylmethane diisocyanates, 4,4’-diphenylmethane diisocyanate is
preferable.
[0030]
The content ratio of the diphenylmethane diisocyanate in the polyisocyanate is, for
example, 80% by mass or more, preferably 90% by mass or more, and, for example, 100% by
mass or less.
[0031]
In addition to the diphenylmethane diisocyanate, the polyisocyanate can contain another
polyisocyanate in a range that is not excluded from the scope of the present invention.
[0032]
Examples of the other polyisocyanate include aliphatic polyisocyanate (for example,
1,5-pentamethylene diisocyanate (PDI) and 1,6-hexamethylene diisocyanate (HDI)), alicyclic
polyisocyanate (for example, 3-isocyanatomethyl-3,5,5-trimethyl cyclohexylisocyanate (IPDI)
and 1,3- and/or 1,4-bis (isocyanatomethyl)cyclohexane (H6XDI) (Trans-isomer, Cis-isomer, or a
mixture thereof), methylenebis (cyclohexyl isocyanate), (4,4’-, 2,4’- or 2,2’-methylenebis
(cyclohexyl isocyanate, Trans,Trans-isomer, Trans,Cis-isomer, or Cis,Cis-isomer of these, or a
mixture thereof)) (H12MDI)), araliphatic polyisocyanate (for example, m- and/or p-xylylene
diisocyanate (XDI)), aromatic polyisocyanate other than diphenylmethane diisocyanate (for
example, and tolylene diisocyanate (TDI)), a modified product modified from the
polyisocyanates (for example, a multimer, an isocyanurate-modified product, a biuret-modified
product, an allophanate-modified product, and a triol adduct), a modified product modified from
diphenylmethane diisocyanate (for example, a multimer, a carbodiimide-modified product, and a
polyphenylmethanepolyisocyanate (polymeric MDI)).
[0033]
7
The content ratio of the other polyisocyanate in the polyisocyanate is, for example, 0%
by mass or more, and, for example, 40% by mass or less, preferably 20% by mass or less, more
preferably 10% by mass or less. The polyisocyanate more preferably consists of a
diphenylmethane diisocyanate.
[0034]
The low molecular-weight diol is, for example, a compound having a straight-chain
alkylene group and two hydroxyl groups bonding to the alkylene group. The low molecularweight diol has a number average molecular weight of 60 g/mol or more and 200 g/mol or less.
Examples of the low molecular-weight diol include dihydric alcohols having 2 to 4 carbon atoms.
Specific examples of the low molecular-weight diol include straight-chain alkane diols (for
example, ethylene glycol, 1,3-propanediol, and 1,4-butanediol), and branched alkane diols (for
example, 1,2-propanediol and 1,3-butanediol).
[0035]
The low molecular-weight diols can be used singly or in combination of two or more.
[0036]
The low molecular-weight diol preferably includes a straight-chain alkane diol having 2
to 4 carbon atoms, and more preferably includes 1,4-butanediol.
[0037]
The hard segment phase has a melting point of 65℃ or more, preferably 75℃ or more,
more preferably 80℃ or more, and, 140℃ or less, preferably 138℃ or less, more preferably
135℃ or less. The melting point of the hard segment phase can be measured by the method
described below in Examples (the same applies hereinafter).
[0038]
The concentration of the hard segment phase in the water-vapor permeable polyurethane
film 2 is, for example, 5% by mass or more, preferably 10% by mass or more, more preferably
12% by mass or more, even more preferably 18% by mass or more, and, for example, 40% by
mass or less, preferably 30% by mass or less.
[0039]
The concentration of the hard segment phase is calculated from the following formula
(1).
8
[MATH. 1]
[in the formula (1), CE represents the low molecular-weight diol (chain extender), NCO
represents the polyisocyanate, Mn represents the number average molecular weight, and M.W.
represents the molecular weight]
The soft segment phase is a region (domain) formed of a high molecular-weight polyol
and is formed by the reaction of the above-described polyisocyanate and the high molecularweight polyol.
[0040]
The high molecular-weight polyol is a compound having 2 or more hydroxyl groups and
a number average molecular weight of 400 g/mol or more, preferably 500 g/mol or more, and,
for example, 10000 g/mol or less, preferably 5000 g/mol or less. Examples of the high
molecular-weight polyol include polyether polyols, polyester polyols, polycarbonate polyols,
polyurethane polyols, epoxy polyols, vegetable oil polyols, polyolefin polyols, acrylic polyols,
silicone polyols, fluorine polyols, and vinyl monomer-modified polyols.
[0041]
Among the high molecular-weight polyols, a polyether polyol, a polyester polyol, and a
polycarbonate polyol are preferable, and a polyether polyol is more preferable.
[0042]
Examples of the polyether polyol include polyoxy (C2 to 3) alkylene polyols,
polytetramethylene ether glycols, and polytrimethylene ether glycols.
[0043]
Examples of the polyoxy (C2 to 3) alkylene polyol include an addition polymer of C2 to
3 alkylene oxides, for example, ethylene oxide and propylene oxide (including a random and/or
block copolymer of 2 or more alkylene oxides) using a low molecular-weight polyol as an
initiator.
9
[0044]
The low molecular-weight polyol is a compound having 2 or more hydroxyl groups and
a number average molecular weight of 60 g/mol or more and less than 400 g/mol, preferably 200
g/mol or less. Examples of the low molecular-weight polyol include the above-described low
molecular-weight diols having a number average molecular weight of 60 g/mol or more and 200
g/mol or less, dihydric alcohols with a number average molecular weight of more than 100 g/mol
and less than 400 g/mol (for example, alkane diols having 5 to 8 carbon atoms such as 1,5-
pentanediol, 1,6-hexanediol, neopentyl glycol, and 3-methyl-1,5-pentanediol, and ether diols
having 4 to 8 carbon atoms such as diethylene glycol and dipropylene glycol), trihydric alcohols
(such as glycerin and trimethylolpropane), and tetrahydric alcohols (such as
tetramethylolmethane (pentaerythritol) and diglycerin).
[0045]
The low molecular-weight polyols as an initiator can be used singly or in combination
of two or more.
[0046]
Among the low molecular-weight polyols used as an initiator, a dihydric alcohol with a
number average molecular weight of more than 100 g/mol and less than 400 g/mol is preferable,
an ether diol having 4 to 8 carbon atoms is more preferable, and a dipropylene glycol is even
more preferable.
[0047]
Specific examples of the polyoxy (C2 to 3) alkylene polyol include polyoxyethylene
glycol, polyoxypropylene glycol, and copolymerized polyols thereof. The polyoxy (C2 to 3)
alkylene polyol can be produced, for example, in the presence of a known alkali catalyst or a
phosphazenium catalyst.
[0048]
Examples of the polytetramethylene ether glycol include a ring-opening polymerized
product obtained by cation polymerization of tetrahydrofuran ((crystalline) polytetramethylene
ether glycol), and noncrystalline polytetramethylene ether glycol obtained by copolymerizing a
polymerization unit of tetrahydrofuran and the above-described low molecular-weight polyol or
alkylene oxide.
10
[0049]
Examples of the polytetramethylene ether glycol further include plants derived
polytetramethylene ether glycol that is produced using tetrahydrofuran produced based on
vegetable material such as furfural as a starting material.
[0050]
Examples of the polytrimethylene ether glycol include a polyol produced by
polycondensation reaction of plants derived 1,3-propanediol.
[0051]
The high molecular-weight polyols can be used singly or in combination of two or more.
[0052]
The high molecular-weight polyol preferably includes a polyether polyol, and more
preferably consists of a polyether polyol. In other words, the soft segment phase is preferably
formed by the reaction of the polyether polyol and polyisocyanate.
[0053]
When the soft segment phase is formed by the reaction of the polyether polyol and
polyisocyanate, the stretchability of the laminate sheet 1 can surely be improved while the
adhesion of the first spunbond nonwoven fabric 3 to the water-vapor permeable polyurethane
film 2 can surely be improved. Further, the water-vapor permeability of the laminate sheet 1
can be improved.
[0054]
The polyether polyol preferably includes a polyoxy (C2 to 3) alkylene polyol and/or
polytetramethylene ether glycol, more preferably consists of a polyoxy (C2 to 3) alkylene polyol
and/or polytetramethylene ether glycol, and even more preferably consists of a polyoxy (C2 to 3)
alkylene polyol and polytetramethylene ether glycol.
[0055]
When the polyether polyol includes a polyoxy (C2 to 3) alkylene polyol and
polytetramethylene ether glycol, the content ratio of the polyoxy (C2 to 3) alkylene polyol to
100% by mass of the total of the polyoxy (C2 to 3) alkylene polyol and polytetramethylene ether
glycol is, for example, 60% by mass or more, preferably 70% by mass or more, more preferably
78% by mass or more, and, for example, 95% by mass or less, preferably 90% by mass or less.
11
[0056]
The polyoxy (C2 to 3) alkylene polyol preferably includes an oxyethylene group. The
content ratio of the oxyethylene group in the polyoxy (C2 to 3) alkylene polyol is, for example,
50% by mass or more, preferably 80% by mass or more, more preferably 85% by mass or more,
and, for example, 100% by mass or less, preferably 95% by mass or less. The polyoxy (C2 to
3) alkylene polyol even more preferably consists of a polyoxyethylene polyol and/or a polyoxy
(ethylene-propylene) copolymerized polyol.
[0057]
The polyether polyol has a number average molecular weight of, for example, 400
g/mol or more, preferably 500 g/mol or more, more preferably 1200 g/mol or more, particularly
preferably 1300 g/mol or more, especially preferably 1500 g/mol or more, and, for example,
4000 g/mol or less, preferably 3000 g/mol or less, more preferably 2800 g/mol or less,
particularly preferably 2500 g/mol or less, especially preferably 2400 g/mol or less.
[0058]
When the number average molecular weight of the polyether polyol is within the abovedescribed range, the stretchability of the laminate sheet 1 can surely be improved while the
adhesion of the first spunbond nonwoven fabric 3 to the water-vapor permeable polyurethane
film 2 can surely be improved. When the number average molecular weight of the polyether
polyol is the above-described lower limit or more, the tackiness properties of the laminate sheet
1 can surely be reduced.
[0059]
The average number of the functional groups of the high molecular-weight polyol is, for
example, 2.0 or more, and, for example, 4.0 or less, preferably 3.0 or less. The average number
of the functional groups of the polyol can be calculated from the charging components.
[0060]
The average values of the hydroxyl groups of the high molecular-weight polyol is, for
example, 35 mgKOH/g or more, preferably 40 mgKOH/g or more, more preferably 45
mgKOH/g or more, and, for example, 115 mgKOH/g or less, preferably 87 mgKOH/g or less,
more preferably 78 mgKOH/g or less.
[0061]
12
Next, the production of the water-vapor permeable polyurethane film 2 is described.
[0062]
To produce the water-vapor permeable polyurethane film 2, first, a water-vapor
permeable polyurethane is prepared.
[0063]
The water-vapor permeable polyurethane can be prepared by, for example, a prepolymer
method.
[0064]
In more detail, the above-described polyisocyanate and the above-described high
molecular-weight polyol are reacted in the following ratio to synthesize an isocyanate groupterminated urethane prepolymer having an isocyanate group at its terminal.
[0065]
At the time, the ratio (NCO/OH) of the isocyanate groups of the polyisocyanate to the
hydroxyl groups of the high molecular-weight polyol is, for example, 1.9 or more, preferably 2.3
or more, more preferably 2.5 or more, and, for example, 3.5 or less, preferably 3.3 or less.
[0066]
Next, the isocyanate group-terminated urethane prepolymer and the above-described
low molecular-weight diol are reacted in a ratio in which the hard segment phase concentration is
within the above-described range.
[0067]
At the time, the ratio (NCO/OH) of the isocyanate groups of the isocyanate groupterminated urethane prepolymer to the hydroxyl groups of the low molecular-weight diol is, for
example, 0.990 or more, preferably 1.005 or more, and, for example, 1.150 or less, preferably
1.100 or less.
[0068]
In this manner, the water-vapor permeable polyurethane is prepared.
[0069]
The water-vapor permeable polyurethane can be produced also by a one-shot method.
In the one-shot method, for example, the polyisocyanate, high molecular-weight polyol, and low
molecular-weight diol are reacted at a time in a ratio in which the hard segment phase
13
concentration is within the above-described range to prepare the water-vapor permeable
polyurethane.
[0070]
The water-vapor permeable polyurethane produced as described above is a
thermoplastic polyurethane. Thus, the produced water-vapor permeable polyurethane is
crushed into pellets and then formed into a film or a sheet by, for example, a known method such
as extrusion. The pelletization and extrusion step preferably includes a filtration operation, for
example, described in JP patent No. 4332627 to reduce the fisheyes in the water-vapor
permeable polyurethane.
[0071]
As described above, the water-vapor permeable polyurethane film 2 is produced.
[0072]
In the preparation of the water-vapor permeable polyurethane film 2, as necessary, a
known additive such as an antioxidant (for example, a hindered phenolic antioxidant), an
ultraviolet absorber (for example, a benzotriazole type ultraviolet absorber, a triazine type
ultraviolet absorber, or a benzophenone type ultraviolet absorber), an lubricant, a release agent,
or a pigment such as titanium oxide can be added at an appropriate time and ratio. In this case,
the water-vapor permeable polyurethane film 2 contains a known additive in addition to the
water-vapor permeable polyurethane.
[0073]
The first spunbond nonwoven fabric 3 is disposed on one side in the thickness direction
of the water-vapor permeable polyurethane film 2. More specifically, the first spunbond
nonwoven fabric 3 is disposed on a surface of the water-vapor permeable polyurethane film 2
(one surface in the thickness direction) and is in direct contact with the surface of the watervapor permeable polyurethane film 2.
[0074]
The first spunbond nonwoven fabric 3 is laminated on the water-vapor permeable
polyurethane film 2 without an adhesive. At least a part of the first spunbond nonwoven fabric
3 is fusion joined to the surface of the water-vapor permeable polyurethane film 2. Especially,
14
at least a part of stretchable fibers containing a thermoplastic polyurethane described below is
fusion joined to the surface of the water-vapor permeable polyurethane film 2.
[0075]
The first spunbond nonwoven fabric 3 includes the stretchable fibers containing a
thermoplastic polyurethane and non-stretchable fibers containing a polyolefin.
[0076]
The stretchable fibers are polyurethane fibers made of a thermoplastic polyurethane as a
material. Examples of the thermoplastic polyurethane include a thermoplastic polyurethane
elastomer (A1) described in Japanese Unexamined Patent Publication No. 2008-213284.
[0077]
The thermoplastic polyurethane is produced, for example, by the reaction of the abovedescribed polyisocyanate (preferably, a diphenylmethane diisocyanate), the above-described
high molecular-weight polyol (preferably, a polyester polyol), and the above-described low
molecular-weight polyol (preferably, the above-described low molecular-weight diol). For
example, the thermoplastic polyurethane can be produced by a known method such as a
prepolymer method or a prepolymer method, similarly to the water-vapor permeable
polyurethane.
[0078]
In this manner, the thermoplastic polyurethane is produced.
[0079]
In the preparation of the thermoplastic polyurethane, as necessary, the above-described
known additive can be added at an appropriate time and ratio. In this case, the stretchable
fibers contain the known additive in addition to the thermoplastic polyurethane.
[0080]
The thermoplastic polyurethane has a hardness of, for example, 70 A or more,
preferably 73 A or more, more preferably 75 A or more, and, for example, 95 A or less,
preferably 90 A or less, more preferably 88 A or less, even more preferably 85 A or less. The
hardness of the thermoplastic polyurethane can be measured at 23℃ and 50% relative humidity
by the method according to JIS K-7311 (durometer: type A) (the same applies hereinafter).
[0081]
15
The thermoplastic polyurethane has a tensile strength of, for example, 20 MPa or more,
preferably 30 MPa or more, and, for example, 70 MPa or less, preferably 60 MPa or less. The
tensile strength of the thermoplastic polyurethane can be measured by the method according to
JIS K-7311 (the same applies hereinafter).
[0082]
The elongation at break of the thermoplastic polyurethane is, for example, 300% or
more, preferably 400% or more, for example, 700% or less, preferably 600% or less. The
elongation at break of the thermoplastic polyurethane can be measured by the method according
to JIS K-7311 (the same applies hereinafter).
[0083]
The content ratio of the stretchable fibers in the first spunbond nonwoven fabric 3 is, for
example, 30% by mass or more, and, for further improvement of the stretchability, preferably
35% by mass or more. Similarly, for further improvement of the tackiness properties, the
content ratio of the stretchable fibers is, for example, 70% by mass or less, preferably 60% by
mass or less.
[0084]
The non-stretchable fibers are polyolefin fibers made of a polyolefin as a material.
Examples of the polyolefin include the polyolefin (B) described in Japanese Unexamined Patent
Publication No. 2008-213284.
[0085]
Specific examples of the polyolefin include polyethylenes, polypropylenes, and
polyethylenepolypropylene copolymers.
[0086]
The polyolefins can be used singly or in combination of two or more.
[0087]
The polyolefin preferably includes polyethylene and/or polypropylene, more preferably
includes polyethylene (more specifically, a high-density polyethylene) and polypropylene, and
even more preferably consists of polyethylene (more specifically, a high-density polyethylene)
and polypropylene.
[0088]
16
The content ratio of the polypropylene to 100% by mass of the total of the polyethylene
and polypropylene is, for example, 80% by mass or more, preferably 90% by mass or more, and,
for example, 100% by mass or less, preferably 99% by mass or less.
[0089]
The melt flow rate (MFR) of the polypropylene measured at a temperature of 230℃ and
a load of 2.16 kgf in conformity to ASTM D1238 is, for example, 10 g/10 minutes or more,
preferably 20 g/10 minutes or more, and, for example, 1000 g/10 minutes or less, preferably 100
g/10 minutes or less.
[0090]
The density of the polypropylene is, for example, 0.900 g/cm3
or more and 0.920 g/cm3
or less.
[0091]
The polypropylene has a melting point of, for example, 120℃ or more, preferably
140℃ or more, and, for example, 200℃ or less, preferably 180℃ or less.
[0092]
The melt flow rate (MFR) of the polyethylene measured at a temperature of 230℃ and a
load of 2.16 kgf in conformity to ASTM D1238 is, for example, 1 g/10 minutes or more, and, for
further improvement of the spinnability, preferably 2 g/10 minutes or more. Similarly, the
MFR of the polyethylene is, for example, 1000 g/10 minutes or less, and, for further
improvement of the expansibility, preferably 100 g/10 minutes or less, more preferably 20 g/10
minutes or less.
[0093]
The polyethylene has a density of, for example, 0.940 g/cm3
or more, and, for further
improvement of the spinnability, preferably 0.950 g/cm3
or more. The density of the
polyethylene is, for example, 0.980 g/cm3
or less, and, for further improvement of the
formability, preferably 0.975 g/cm3
or less.
[0094]
The polyethylene has a melting point of, for example, 100℃ or more, preferably 120℃
or more, and, for example, 180℃ or less, preferably 160℃ or less.
[0095]
17
The content ratio of the non-stretchable fibers in the first spunbond nonwoven fabric 3
is, for example, 30% by mass or more, preferably 40% by mass or more, and, for example, 70%
by mass or less, preferably 65% by mass or less.
[0096]
The first spunbond nonwoven fabric 3 can contain other fibers in addition to the abovedescribed stretchable fibers (polyurethane fibers) and non-stretchable fibers (polyolefin fibers) in
a range that does not reduce the effects of the present invention. Examples of the other fibers
include polystyrene fibers, polyvinyl chloride fibers, polyester fibers, and polyamide fibers.
[0097]
The ratio of the other fibers in the first spunbond nonwoven fabric 3 is, for example, 0%
by mass or more, and, for example, 10% by mass or less, preferably 5% by mass or less. The
first spunbond nonwoven fabric 3 more preferably consists of stretchable fibers (polyurethane
fibers) and non-stretchable fibers (polyolefin fibers).
[0098]
The unit weight of the first spunbond nonwoven fabric 3 is, for example, 10 g/m2
or
more, preferably 15 g/m2
or more, more preferably 20 g/m2
or more, and, for example, 100 g/m2
or less, preferably 40 g/m2
or less, more preferably 30 g/m2
or less.
[0099]
Next, the production of the first spunbond nonwoven fabric 3 is described. The first
spunbond nonwoven fabric 3 can be produced by, for example, the method of producing a
stretchable nonwoven fabric described in Japanese Unexamined Patent Publication No. 2004-
244791.
[0100]
More specifically, the above-described thermoplastic polyurethane and the abovedescribed polyolefin are individually fusion melt by a known extruder, and melt spinning is
carried out by a spunbond method using the spunbond molding machine including the spinneret
plate shown in FIG. 2 of Japanese Unexamined Patent Publication No. 2004-244791. In detail,
the spinneret plate includes a plurality of first nozzles discharging the thermoplastic
polyurethane and a plurality of second nozzles discharging the polyolefin. The stretchable
fibers containing the thermoplastic polyurethane are discharged from the first nozzles and
18
simultaneously the non-stretchable fibers containing the polyolefin are discharged from the
second nozzles. In this manner, a web (mixed fibers) that is a mixture of the thermoplastic
polyurethane stretchable fibers and the polyolefin non-stretchable fibers is deposited on the
collection surface. Thereafter, the web is joined by heat fusion, for example, with heat
embossing rolls to partially join the stretchable fibers and the non-stretchable fibers by heat
fusion. In this manner, the first spunbond nonwoven fabric 3 is prepared.
[0101]
The second spunbond nonwoven fabric 4 is disposed at the other side in the thickness
direction of the water-vapor permeable polyurethane film 2. More specifically, the second
spunbond nonwoven fabric 4 is disposed on a back surface of the water-vapor permeable
polyurethane film 2 (one surface in the thickness direction), and is in direct contact with the back
surface of the water-vapor permeable polyurethane film 2. The second spunbond nonwoven
fabric 4 has the same structure as that of the first spunbond nonwoven fabric 3 and contains the
stretchable fibers containing the thermoplastic polyurethane and the non-stretchable fibers
containing the polyolefin. Thus, the description of the second spunbond nonwoven fabric 4 is
omitted.
[0102]

Next, with reference to FIG. 2, one embodiment of the method for manufacturing the
laminate sheet 1 is described.
[0103]
The method for manufacturing the laminate sheet 1 includes a step of preparing a
spunbond nonwoven fabric, a step of preparing a water-vapor permeable polyurethane film, a
step of laminating the spunbond nonwoven fabric and the water-vapor permeable polyurethane
film, and a step of subjecting the laminated spunbond nonwoven fabric and water-vapor
permeable polyurethane film to a stretching process.
[0104]
The method for manufacturing the laminate sheet 1 is continuously carried out, for
example, by a melt extrusion laminator 10 illustrated in FIG. 2.
[0105]
19
The melt extrusion laminator 10 includes an extruder 11, a first lamination roll 12, a
second lamination roll 13, a first delivery roll 14, a second delivery roll 15, a plurality of cooling
rolls 16, and a stretching apparatus 17.
[0106]
The extruder 11 is a known extruder and extrudes the above-described water-vapor
permeable polyurethane into a sheet shape to discharge the water-vapor permeable polyurethane
film 2. The water-vapor permeable polyurethane film 2 may not be solidified just after being
discharged. The extruder 11 has a T die. The extruder 11 can adjust the temperature of the T
die.
[0107]
The first lamination roll 12 and the second lamination roll 13 are located on the
downstream side in relation to the extruder 11 in a discharge direction. The first lamination roll
12 and the second lamination roll 13 face each other. Each of the first lamination roll 12 and
the second lamination roll 13 is rotatable. The temperature of each of the first lamination roll
12 and the second lamination roll 13 is adjustable.
[0108]
The water-vapor permeable polyurethane film 2 is discharged from the extruder 11 and
fed between the first lamination roll 12 and the second lamination roll 13. The first lamination
roll 12 and the second lamination roll 13 can laminate the first spunbond nonwoven fabric 3 and
the second spunbond nonwoven fabric 4 on the fed water-vapor permeable polyurethane film 2
from both sides of the water-vapor permeable polyurethane film 2. The first lamination roll 12
is movable in relation to the second lamination roll 13. This motion enables the first lamination
roll 12 to adjust a nip pressure applied on the first spunbond nonwoven fabric 3, water-vapor
permeable polyurethane film 2, and second spunbond nonwoven fabric 4 that are held between
the first lamination roll 12 and the second lamination roll 13.
[0109]
The elongated first spunbond nonwoven fabric 3 is wound around the first delivery roll
14 in advance. The elongated first spunbond nonwoven fabric 3 is prepared by the abovedescribed method in advance. The first spunbond nonwoven fabric 3 wound around the first
delivery roll 14 is yet to be subjected to the stretching process. The first delivery roll 14 is
20
rotatable and capable of delivering the first spunbond nonwoven fabric 3 yet to be stretched.
From the upstream in the discharge direction in which the extruder 11 discharges the film, the
first delivery roll 14 feeds the first spunbond nonwoven fabric 3 between the first lamination roll
12 and the second lamination roll 13 to bring the first spunbond nonwoven fabric 3 into contact
with the one surface in the thickness direction of the water-vapor permeable polyurethane film 2.
[0110]
The second delivery roll 15 is located at the opposite side to the first delivery roll 14
across the extruder 11. The elongated second spunbond nonwoven fabric 4 is wound around
the second delivery roll 15 in advance. The elongated second spunbond nonwoven fabric 4 is
prepared by the above-described method in advance. The second spunbond nonwoven fabric 4
wound around the second delivery roll 15 is yet to be subjected to the stretching process. The
second delivery roll 15 is rotatable and capable of delivering the second spunbond nonwoven
fabric 4 yet to be stretched. From the upstream in the discharge direction of the extruder 11, the
second delivery roll 15 feeds the second spunbond nonwoven fabric 4 between the first
lamination roll 12 and the second lamination roll 13 to bring the second spunbond nonwoven
fabric 4 into contact with the other surface in the thickness direction of the water-vapor
permeable polyurethane film 2.
[0111]
The cooling rolls 16 cool a laminate 20 that is obtained by laminating the first spunbond
nonwoven fabric 3, water-vapor permeable polyurethane film 2, and second spunbond nonwoven
fabric 4 between the first lamination roll 12 and the second lamination roll 13. The temperature
of each of the cooling rolls 16 is adjustable.
[0112]
The stretching apparatus 17 is a gear stretching apparatus, for example, described in
Japanese Unexamined Patent Publication No. 2004-244791. The stretching apparatus 17
stretches the laminate 20 by gear stretching after the cooling by the cooling rolls 16, thereby
preparing the laminate sheet 1. The stretching apparatus 17 includes a first gear roll 18 and a
second gear roll 19.
[0113]
21
Each of circumferential surfaces of the first gear roll 18 and the second gear roll 19 has
a plurality of gear teeth extending in a circumferential direction. The first gear roll 18 and the
second gear roll 19 face each other to be engaged with each other. Each of the first gear roll 18
and the second gear roll 19 is rotatable. The laminate 20 is cooled by the cooling rolls 16, and
fed and held between the first gear roll 18 and the second gear roll 19 to be gear stretched.
[0114]
To produce the laminate sheet 1 with the melt extrusion laminator 10, first, (pellets of)
the water-vapor permeable polyurethane prepared as described above (are) is set in the extruder
11.
[0115]
It is preferable to reduce the water content of the pellets of the water-vapor permeable
polyurethane to, for example, 500 ppm or less, preferably 300 ppm or less, more preferably 200
ppm or less by using a dehumidification dryer in order to improve the mechanical properties and
water-vapor permeability of the water-vapor permeable polyurethane film. It is preferable to
connect the dehumidification dryer to the extruder to convey the pellets without contact with air.
[0116]
The temperature of the T die of the extruder 11 is adjusted to, for example, 180℃ or
more and 250℃ or less. Thereafter, the molten water-vapor permeable polyurethane is
extruded into a film shape from the T die. In this manner, the water-vapor permeable
polyurethane film 2, which is made of the molten water-vapor permeable polyurethane, is
prepared.
[0117]
Then, the molten water-vapor permeable polyurethane film 2 is fed between the first
lamination roll 12 and the second lamination roll 13. At the time, the first spunbond nonwoven
fabric 3 is delivered from the first delivery roll 14 and fed between the molten water-vapor
permeable polyurethane film 2 and the first lamination roll 12 while the second spunbond
nonwoven fabric 4 is delivered from the second delivery roll 15 and fed between the molten
water-vapor permeable polyurethane film 2 and the second lamination roll 13.
[0118]
22
In this manner, the first spunbond nonwoven fabric 3 is in direct contact with the
surface of the molten water-vapor permeable polyurethane film 2 (the one surface in the
thickness direction). The second spunbond nonwoven fabric 4 is in direct contact with the back
surface of the molten water-vapor permeable polyurethane film 2 (the other surface in the
thickness direction).
[0119]
Then, the first spunbond nonwoven fabric 3, the molten water-vapor permeable
polyurethane film 2, and the second spunbond nonwoven fabric 4 are held between the first
lamination roll 12 and the second lamination roll 13. Thus, the nip pressure of the first
lamination roll 12 and the second lamination roll 13 is exerted to move the first spunbond
nonwoven fabric 3 and the second spunbond nonwoven fabric 4 onto the whole of the molten
water-vapor permeable polyurethane film 2 in a width direction.
[0120]
The nip pressure (gauge pressure) is, for example, 0.1 MPaG or more, preferably 0.3
MPaG or more, and, for example, 2.0 MPaG or less, preferably 1.0 MPaG or less, more
preferably 0.6 MPaG or less.
[0121]
The temperature of each of the first lamination roll 12 and the second lamination roll 13
is, for example, 10℃ or more, preferably 15℃ or more, more preferably 20℃ or more, and, for
example, 50℃ or less, preferably 40℃ or less.
[0122]
Then, the first spunbond nonwoven fabric 3 and the second spunbond nonwoven fabric
4 are laminated on both surfaces of the molten water-vapor permeable polyurethane film 2.
[0123]
In this manner, the first spunbond nonwoven fabric 3, the water-vapor permeable
polyurethane film 2, and the second spunbond nonwoven fabric 4 are sequentially laminated,
thereby preparing the laminate 20.
[0124]
In the laminate 20, the molten water-vapor permeable polyurethane located on the
surface of the water-vapor permeable polyurethane film 2 is fusion joined to at least a part
23
(especially, the stretchable fibers) of the first spunbond nonwoven fabric 3. Further, the molten
water-vapor permeable polyurethane located on the back surface of the water-vapor permeable
polyurethane film 2 is fusion joined to at least a part (especially, the stretchable fibers) of the
second spunbond nonwoven fabric 4.
[0125]
Thereafter, the laminate 20 passes on the second lamination roll 13 and is drawn
through the cooling rolls 16.
[0126]
In this manner, the molten water-vapor permeable polyurethane film 2 is solidified and
the first spunbond nonwoven fabric 3 and the second spunbond nonwoven fabric 4 are adhered to
the water-vapor permeable polyurethane film 2 without using an adhesive.
[0127]
The cooling rolls 16 have, for example, a temperature lower than or equal to that of the
second lamination roll 13. The cooling rolls 16 have a temperature of, for example, 0℃ or
more, preferably 10℃ or more, and, for example, 40℃ or less, preferably 30℃ or less.
[0128]
Thereafter, the cooled laminate 20 is fed and held between the first gear roll 18 and the
second gear roll 19 to be stretched by the gear stretching process.
[0129]
The stretching ratio of the gear stretching process is, for example, 1.5 times or more,
preferably 2.0 times or more, and, for example, 5 times or less, preferably 4.0 times or less.
When the stretching ratio is the above-described lower limit or more, the stretchability tends to
further improve. When the stretching ratio is the above-described upper limit or less, the
damage to the water-vapor permeable polyurethane film 2, and the first spunbond nonwoven
fabric and second spunbond nonwoven fabric reduces. Thus, the wearing by fiber breakage, the
reduction in strength, and the reduction in peeling strength tend to further be prevented.
[0130]
The stretching direction of the gear stretching process may be a machine direction (MD)
or a cross direction (CD). In view of the running stability during the molding process, the
stretching direction is preferably the cross direction (CD). When the gear process is carried out
24
in the cross direction (CD), a known continuous process or batch process may be used. When
the stretching is carried out in the machine direction (MD), a known gear process method or roll
stretching method may be used. Alternatively, depending on the purpose, the machine direction
(MD) and cross direction (CD) can be combined.
[0131]
The laminate sheet 1 is produced as described above.
[0132]
Examples of the use of the laminate sheet 1 include domestic use, medical and hygienic
use, industrial use, civil engineering and architectural use, agricultural and horticultural use, and
clothing use. More specifically, the laminate sheet 1 is used for the sanitary materials (for
example, disposable diapers, menstrual pads, urinal pads, gauzes, masks, wet wipes, laboratory
coats, and dust masks), the medical materials (for example, surgical coats and medical bandages),
and birthing pads, and medical caps. Preferably, the laminate sheet 1 is used for sanitary
materials and medical materials. In other words, the sanitary materials include the abovedescribed laminate sheet 1. The medical materials include the above-described laminate sheet 1.
The sanitary materials and medical materials include the above-described laminate sheet 1 and
thus can achieve excellent stretchability and excellent adhesion while simultaneously reducing
the tackiness properties.
[0133]
Further, the laminate sheet 1 can be used for housewares materials such as rugs, base
fabrics for rugs, storage bags, wrapping cloths, garment covers, tea bags, drainage sheets, wipers,
shoes, slippers, and bags. Further, the laminate sheet 1 can be used for industrial materials such
as interior accessories for cars such as floor mats, various filters for cars, polishing materials,
papermaking felts, wire banding tapes, battery cell separators, air filters, and liquid filters.
Furthermore, the laminate sheet 1 can be used for interlinings for cloths, pads for brassieres,
shoulder pads, event jumpers, and synthetic leathers (such as synthetic leather base fabrics and
vinyl chloride leathers).
[0134]

25
In the laminate sheet 1, the hard segment phase of the water-vapor permeable
polyurethane film 2 has a melting point of the above-described upper limit or less, and the first
spunbond nonwoven fabric 3 contains the stretchable fibers containing the thermoplastic
polyurethane. Thus, the stretchability of the laminate sheet 1 can be improved while the
adhesion of the first spunbond nonwoven fabric 3 to the water-vapor permeable polyurethane
film 2 can be improved. Further, the hard segment phase of the water-vapor permeable
polyurethane film 2 has a melting point of the above-described lower limit or more, and the first
spunbond nonwoven fabric 3 contains the non-stretchable fibers containing the polyolefin.
Thus, the tackiness properties of the laminate sheet 1 can be reduced.
[0135]
Furthermore, the soft segment phase of the water-vapor permeable polyurethane film 2
is preferably formed by the reaction of the polyether polyol and polyisocyanate. Thus, the
stretchability of the laminate sheet 1 can surely be improved while the adhesion of the first
spunbond nonwoven fabric 3 to the water-vapor permeable polyurethane film 2 can surely be
improved. In addition, the water-vapor permeability of the laminate sheet 1 can be improved.
[0136]
The number average molecular weight of the polyether polyol forming the soft segment
phase is preferably within the above-described range or more. Thus, the stretchability of the
laminate sheet 1 can surely be improved while the adhesion of the first spunbond nonwoven
fabric 3 to the water-vapor permeable polyurethane film 2 can surely be improved. In addition,
the tackiness properties of the laminate sheet 1 can surely be reduced.
[0137]
As illustrated in FIG. 2, in the method for manufacturing the laminate sheet 1, the first
spunbond nonwoven fabric 3, the water-vapor permeable polyurethane film 2, and the second
spunbond nonwoven fabric 4 are laminated, and thereafter the stretching process is carried out by
the stretching apparatus 17. Thus, the laminate sheet 1 having the above-described properties
can smoothly be manufactured.
[0138]

26
The above-described laminate sheet 1 includes the water-vapor permeable polyurethane
film 2, the first spunbond nonwoven fabric 3, and the second spunbond nonwoven fabric 4.
However, the present invention is not limited to the above description.
[0139]
The laminate sheet 1 may not include the second spunbond nonwoven fabric 4 and may
consist of the water-vapor permeable polyurethane film 2 and the first spunbond nonwoven
fabric 3.
[0140]
Alternatively, the laminate sheet 1 can include another layer in addition to the watervapor permeable polyurethane film 2 and the first spunbond nonwoven fabric 3 in a range that
does not reduce the effects of the present invention. Examples of the other layer include
spunbond nonwoven fabrics other than the above-described spunbond nonwoven fabrics,
meltblown nonwoven fabrics, wet nonwoven fabrics, dry nonwoven fabrics, needle punched
nonwoven fabrics, stitch bonded nonwoven fabrics, films, natural fiber assemblies (for example,
silks, gauzes, cottons and rayons).

CLAIMS
1. A laminate sheet comprising:
a water-vapor permeable polyurethane film having a hard segment phase; and
a first spunbond nonwoven fabric disposed at one side in a thickness direction of the
water-vapor permeable polyurethane film, the first spunbond nonwoven fabric containing
stretchable fibers containing a thermoplastic polyurethane and non-stretchable fibers containing
a polyolefin, wherein
the hard segment phase has a melting point of 65℃ or more and 140℃ or less.
2. The laminate sheet according to claim 1, wherein
the water-vapor permeable polyurethane film has a soft segment phase, and
the soft segment phase is formed by a reaction of a polyether polyol and a polyisocyanate.
3. The laminate sheet according to claim 2, wherein
the polyether polyol has a number average molecular weight of 1200 g/mol or more and
2800 g/mol or less.
4. The laminate sheet according to claim 1, further comprising:
a second spunbond nonwoven fabric disposed at the other side in the thickness direction
of the water-vapor permeable polyurethane film, the second spunbond nonwoven fabric
containing stretchable fibers containing a thermoplastic polyurethane and non-stretchable fibers
containing a polyolefin.
5. The laminate sheet according to claim 1, wherein
the first spunbond nonwoven fabric is in direct contact with a one-side surface in the
thickness direction of the water-vapor permeable polyurethane film.
6. A sanitary material comprising the laminate sheet according to claim 1.
7. A medical material comprising the laminate sheet according to claim 1.
50
8. A method for manufacturing a laminate sheet, the method comprising:
a step of mixing and joining stretchable fibers containing a thermoplastic polyurethane
and non-stretchable fibers containing a polyolefin by heat fusion to prepare a spunbond
nonwoven fabric;
a step of preparing a water-vapor permeable polyurethane film having a hard segment
phase, the hard segment phase having a melting point of 65℃ or more and 140℃ or less;
a step of applying pressure on the spunbond nonwoven fabric against the water-vapor
permeable polyurethane film to laminate the spunbond nonwoven fabric and the water-vapor
permeable polyurethane film; and
a step of subjecting the spunbond nonwoven fabric to a stretching process before the
laminating step; and/or
a step of subjecting the laminated spunbond nonwoven fabric and water-vapor
permeable polyurethane film to a stretching process after the laminating step.
9. The method according to claim 8, wherein
the spunbond nonwoven fabric is in direct contact with a one-side surface in a thickness
direction of the water-vapor permeable polyurethane film in the step of laminating the spunbond
nonwoven fabric and the water-vapor permeable polyurethane film.