DESCRIPTION
MULTILAYER NONWOVEN FABRIC FOR FOAM MOLDING, METHOD OF
PRODUCING MULTILAYER NONWOVEN FABRIC FOR FOAM MOLDING,
URETHANE-FOAM MOLDED COMPLEX USING MULTILAYER NON,WOVEN
FABRIC, VEHICLE SEAT, AND CHAIR
Technical Field
[0001] The present invention relates to a multilayer nonwoven fabric for foam molding
arranged in a bottom portion of a foam molded article such as polyurethane, a method of
producing a tnultilayer nonwoven fabric for foam molding, a t~rethane-foamm olded complex
using the multilayer nonwoven fabric, a vehicle seat, and a chair,
Background Art
[0002] Foam molded articles such as flexible polyurethane foatns are used as a cushionitlg
material for a product such as a vehicle seat. At the bottom portion of the foam molded
articles, a reinforcing base fabric is arranged in order to enhance the rigidity of the urethane
foam tnolded article as well as to prevent the leakage of urethane to the back side of the
article. Exatuples of the reinforcing base fabric include a combination of a cheesecloth
(victoria lawn) and slab urethane, and a coarse blanket. However, such reinforcing base
fabrics are insufficient in improving the rigidity o f the urethane foam molded articles, or
insufficient for preventing the leakage of urethatle to the back side, wltich are of a problem.
[0003] As a method of improving the above defects, there have been proposed various
methods such as a method using, as a ieinforcing base fabric, a nonwoven fabric in which a
thin dense layer having a basis weight of 10 g/m2 to 30 g/m2 and a coarse bulky layer having a
basis weight of 40 g/m2 to 100 ghn2 are integrated with each other (see, for example, Japatlese
Utility Model Applicafion~Publication(J P-Y)N o. S62-26193), a method using a high basis
weight non\voven fabric having a basis weight of 110 g/~ntZo 800 g/m2 aud a fiber diameter
of 1 d to 16 d (see, for example, Japanese Patent Application Laid-Open (JP-A) No.
H2-258332), a method using a meltblown nonwoven fabric haviug a fiber diameter of 10 pm
or less as a dense layer (see, for example, JP-A No. 2004-353 153), a method using a
nonwoven fabric in which a web (a dense layer) formed of fibers having a fineness of 1 . 1 dtex
to 2.7 dtex and a web (a bulky layer) formed of fibers having a fineness of 2.3 dtex to 8.8 dtex
are provided by mechanically entangling (see, for example, JP-A No. 2007-146356), aud a
method using, as a reinforcing material for a foam molded article, a multila)~ero btained by
1
integrating a fibrous substrate layer such as a spunbonded non\voven fabric and a staple fiber
layet; provided on at least one side of the fibrous substrate layer, through the action of
high-pressure water flow (see, for example, JP-A No. 2005-2 12204).
[0004] Howeve]; the reinforcing base fabrics for foam molding described in the above
documents are all directed to solving problematic leakage during urethane foam formation
and impregnation performance, and they are not materials which can reduce troublesome
manual labor, such as cutting and sewing, before foam molding.
[0005] As vehicle seats become more advanced in design and involve more electronic
components in recent years, the shapes of metal molds during urethane foatn formation have
become complicated. The need to conform to such complicated shapes causes a sig~xificant
increase in labor in manually cutting and sewing the reinforcing base fabrics. As a method
of saving the labor, there has been proposed a molding processing method in which a mold is
covered with a nonwoven fabric sheet, and the nonwoven fabric sheet is tben heated, spread,
and compressed to conform to the shape of the mold, \vhereby processing before foam
formation is easily performed. As an example of the reinforcit~gb ase fabrics used in this
molding processing method, a nonwoven fabric sheet including a mixture of
low-melting-point fibers and high-melting-point fibers is exemplified (see, for example, JP-A
No. 2006-281768). Furthet; it has been proposed that a nonwoven fabric mainly cotnposed
o f conjugate staple fibers including high and lo\v melting components of polyester resin is
used as an urethane reinforcing material to eliminate the need of cutting as well as to prevent
the leakage of urethane during molding in the molding processing of urethane foams (see, for
example, JP-A Nos. 20 12-82548 and 20 13- 129950).
[0006] Furtliel; there has been proposed to provide a dense layer to secure denseness (for
exatnple, JP-ANo. 2013-129950). Furthermore, there has been proposed a multilayer
nonwoven fabric for foatn formation in which a reinforcing layer is provided on at least one
side of a dense layel; and the dense layer is fonned by providing a spunbotlded nonwoven
fabric layer on both sides ofa m~ltblownn onwoven fabric layer and the meltblown nonwoven
fabric layer and the spunbonded nonwoven fabric layer are partially
thennocompression-bonded with each other (see, for exatnple, WO 2012/008169). It is
described that this tnoltilayer nonwoven fabrics for foam formation have excellent resistance
to the separation of layers, and even \\then the multilayer is provided (entangled) using a
needle punch, surface powdering caused by fiber waste of the rneltblowtl nonwoven fabric
layer is reduced.
SUMMARY OF lNVENTION
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Technical Problem
[0007] In the nonwoven fabrics obtained by tlle tecllniques disclosed in the above JP-A Nos.
2006-28 1768,20 12-82548, and 2013-129950, conformity to the shape of a tnold is improved,
and the labor in sewing can be reduced. Howevel; there is a problem that since a nonwoven
fabric formed of staple fibers is cxcessively stretched while following the shape of a mold, an
extremely thin portion with insufficient denseness is formed. In the nonwoven fabric
obtained by the technique disclosed in JP-A No. 2013- 129950, there is a problem that the
thickness ofthe nonwoven fabric is extremely reduced by thermal compression in the
thickness direction wvhile the non\\oven fabric follo\vs to the shape of a mold. In any case,
when orethane foaming as a subsequent process is performed, urethane leaks to the back side
through such a thin portion to possibly cause problems such as low reinforcing effects, the
occurrence of unusual noises between the urethane and metal springs, and low
comfortableness of chairs and the like, using those non\troven fabrics. In the technique
disclosed in WO 20 121008169, although the denseness is satisfactorily maintained even ifthe
tnultilayer nonwoven fabric is stretched \vhile following the shape of a mold, a thin portion is
formed by compression in the thickness direction, and urethane may leak during urethane
foaming. Namely, there has not been obtained a flexible material \vhose denseness is
satisfactorily maintained even if the material is stretched while being heated, spread, and
compressed to confortn to the shape of a mold and in which reduction in thickness is
prevented even if the material is subjected to thermal comp~.ession in the thickness direction.
[0008] An object of the invention is to provide a inultilayer nonwoven fabric for foam
nlolding, which exhibits an excellent cotlfornlity to the shape of a mold during molding
processing involving heating, spreading, and compressing and satisfactorily maintains
denseness even if being stretched, in which reduction in thickness is prevented even ifthe
~nultilayern onwoven fabric is subjected to thertnal cotnpression in the thickness direction,
and which exhibits an excellent balance of reinforcing effects, performance of preventing
urethane leakage (noise prevention perfortnance), and flexibility of a nonwoven fabric layer
(comfortableness of chairs and the like using the tnultilayer nonwoven fabric) after being
shaped to the mold, a urethane-foam molded complex using the multilayer nonwoven fabric, a
vehicle seat and a chair using the tnultilayer nonwoven fabric, and a tnetllod of producing a
mitltilayer nonwoven fabric for foam molding.
Solution to Problem
[0009] The means for solving the above problems are as follo\vs.
[0010] A multilayer non\\roven fabric for foam molding, containing:
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a dense layer; and
a reinforcing layer provided on at least one side ofthe dense layel; whelein the
reinforcing layer is a staple fiber nonwoven fabric containing:
thermoplastic resin staple fibers (A) having a fiber diameter of inore than 20
ptn, in an amount of 5% by Inass to 50% by tnass, and
thermoplastic resin staple fibers @) having a fiber diameter of 20 ptn or less,
in an atnount of 95% by mass to 50% by mass,
wherein a total of the thermoplastic resin staple fibers (A) and the thermoplastic resin
staple fibers (B) is 100% by mass, the thern~oplasticre sin staple fibers (A) or the
ther~noplasticre sin staple fibers (B) contain conjugate polyester-based staple fibers (C)
fonned containing two or more resins having different tnelting points, and the conjugate
polyester-based staple fibers (C) are contained in the reinforcing layer in an atnount of 10%
by niass to 40% by tnass,
wherein the dense layer is a nonwoven fabric having bulk density in a range of from
0.05 g/cm3 to 0.3 g/cm3, and
wherein the dense layer and the reinforcing layer are entangled with each other by
needle panching.
[001 I] <2> The tnultilayer nonwoven fabric for foam molding according to , wherein a
thickness ofthe fabric is fiotn 1.6 tnm to 5.0 nnn.
[0012] <3> The multilayer nonwoven fabric for foam tnolding according to or <2>,
wherein a thickness of the fabric after being held at 1 IO°C and 4.9 Pa for 5 minutes is 1.2 tnm
or more.
[0013] <4> The nlultilayer nonwoven fabric for foam molding according to any one of <1>
to <3>, wherein a fiber diameter of at least a portion of the conjugate polyester-based staple
fibers (C) is 20 ptn or less.
[0014] <5> The multilayer nonwoven fabric for foam tnolding according to any one of <1>
to <4>, wherein a melting point of at least one resin that forms the conjugate polyester-based
staple fibers (C) is in a range of from 110°C to 190°C.
[0015] <6> The tnultilayer nonwoven fabric for foam molding according to any one of <1>
to <5>, wherein the dense layer includes a nonwoven fabric that is partially
thermocompression-bonded, air through processed, resin bonded, or calendered.
[0016] <7> The niultilayer nonwvoven fabric for foam tnolditig according to any one of
to <6>, wherein the dense layer is a nonwoven fabric constituted of continuous fibers.
[0017] <8> The tnultilayer nonwoven fabric for foatn molding according to any one of
to <7>, wherein the thermoplastic resin staple fibers (A) and the ther~noplasticre sin staple
fibers (B) are at least one kind of staple fibers selected from the group consisting of
polyester-based staple fibers arid polyolefin-based staple fibers.
[OOI 81 <9> The multilayer nonwoven fabric for foam molding according to any one of <1>
to <8>, \vherein the thermoplastic resin staple fibers (A) and the thermoplastic resin staple
fibers (B) are polyester-based staple fibers.
[0019] The muitilayer nonwoven fabric for foam molding according to ally one of
to i9>, \vhcrein the dense layer includes a continuous fiber nonwoven fabric that is partially
thennocotnpression-bonded.
[0020] The multilayer nonwoven fabric for foatil molding according to any one of
to , wherein a basis weight of the dense layer is in a range of from 10 g/m2 to 35 dm2.
[0021] <12> The multilayer nonwoven fabric for foam molding according to any one of <1>
to , wherein an air permeability of the dense layer is in a range of from 70 cm3/cm2/sec
to 200 cm3/ctn2/sec.
[0022] The multilayer nonwoven fabric for foam molding according to any one of
to <12>, wherein the dense layer comprises a multilayer structure containing:
a melt-blown non\\roven fabric layer (M) that is constituted of continuous fibers, and
a spunbonded noilwoven fabric layer (S) constituted of continuous fibers, and
provided on both sides of the melt-blown nonwoven fabric layer (M); arid
the melt-blown nonwoven fabric layer (M) and each spunbonded nonwoven fabric
layer (S) are partially thermocompression-bonded with each other.
[0023] <14> The multilayer nonwoven fabric for foam molding according to any one of
to <13>, wherein the multilayer nonwoven fabric has an air permeability at a pressure
difference of 125 Pa of from 25 cm3/cm2/sec to 160 cm3/cm2/sec.
[0024] <15> The multilayer nonwoven fabric for faam rnoldi~lga ccording to any one of
to wherein the multilayer nonwoven fabric has a basis weight of from 20 g/m2 to 160
g/1112.
[0025] <16> The mnltilayer nonwoven fabric for foam molding accorditlg to any one of
to <15>, wherein the mu1tila)~ern onwoven fabric llas an air permeability at a pressure
difference of 125 Pa of 25 cm3/cm2/sec to 140 cn~~/cm~/sec.
[0026] <17> The multilayer nonwoven fabric for foam molding according to any one of
to , wherein a basis weight of the reinforcing layer is in a range of from 40 g/m2 to 150
g/n12.
[0027] Atnethod of producing the tnultilayer non\\foven fabric for foam molding
according to any one of to <17>, containing providing the reinforcing layer on at least
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one side of the deuse layet; and, subsequently, entangling the reinforcing layer and the dense
layer with each other by needle punching.
[0028] <19> The method of producing the multilayer nonwoven fabric for foam molding
according to 1 1 0 , wherein the dense layer is formed by providing the spunbonded nonwoven
fabric layer (S) on both sides of the meltblo\vn nonwoven fabric layer (M), and, subsequently,
carrying out partial thermocotnpressio~~-bondinga,i r through processing, resin bonding, or
calendering.
[0029] <20> A urethane-foam molded complex in wllich a urethane foam laycr is provided
on an outer surface o f the reinforcing layer of the multilayer nonwoven fabric for foam
tliolding according to any one of <1> to <17>.
[0030] <21> The urethane-foam molded complex according to <20>, wherein the
reinforcing layer and the urethane foam layer are integrated with each other,
[003 I] <22> A vehicle seat itlcluding the tnultilayer nonwoven fabric for foam molding
according to any one of to <17> or the urethane-foatn molded complex according to
<20> or <2 1 >.
[0032] <23> A chair including the multilayer nouwoven fabric for foam molding according
to any one of to <17> or the urethane-foam molded complex according to <20> or <21>.
Advantageous Etiects of Invention
[0033] The present invention can provide a multilayer n~n\\~ovcn fabric for foam molding,
which exhibits an excellent conformity to the shape of a mold during molding processing
involving heating, spreading, and cornpressing and satisfactorily maintains denseness even i f
being stretched, in which reduction in thickness is prevented even if the tnultilayer nonwoven
fabric is subjected to thermal compressiotl in the thickness direction, and which exhibits an
excellent balance of reinforcing effects, performance of preventing urethane leakage (noise
prevention performance), and flexibility ofa nonwoven fabric layer (comfo~tablenesos f
chairs and the like using the rnultilayer nonwoven fabric) after being shaped to the mold, an
urethane-foam molded cornplex using the cnultilayer nonwoven fabric, a vehicle seat and a
chair using the multilayer nonwoven fabric, and a method of prodocitlg a multilayer
llonwoven fabric for foam inolding.
DESCRIPTION OF EMBODIMENTS
[0034] In this specification, nu~nericalr anges depicted wit11 ''from" and "to" represent
ranges inclusive of the numbers that respectively appear at the left and right of "to" as the
minimt~mv alue and the maximum value, respectively.
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[0035] A ~nultilayern onwoven fabric for foam molding according to thc invention contains
a dense layel; and a reinforcing layer provided 011 at least one side of the dense layet; the
reinforcitig layer is a staple fiber notnvoven fabric containing thennoplastic resin staple fibers
(A) having a fiber diameter of more than 20 Inn, in an amount of 5% by mass to 50% by mass,
and thermoplastic resin staple fibers (B) having a fiber diameter of 20 Inn or less, in at1
amount of 95% by mass to 50% by tnass, a total of the thermoplastic resin staple fibers (A)
and the thermoplastic resin staple fibers (B) is 100% by tnass, the thermoplastic resin staple
fibers (A) or the thermoplastic resin staple fibers (B) contain conjugate polyester-based staple
fibers (C) fornled containing two or more resins having different melting points, and the
conjugate polyester-based staple fibers (C) are contained in the reinforcing layer in an atnolmt
of 10% by tnass to 40% by mass, the dense layer is a non\\lo\len fabric having bulk density in
a range of fiorn 0.05 dcm3 to 0.3 g/cm3, and the dense layer and the reinforcing layer are
entangled \\?th each other by needle punching.
[0036] In a multilayer nonwoven fabric for foam tnolding according to the invention, a
dense layer of a nonwoven fabric having a bulk density in a range of fro111 0.05 g/cm3 to 0.3
g/cm3 and a reinforcing layer which is a nonwoven fabric containing a specific amount of
specific staple fibers are provided while being entangled with each other by needle ponching,
whereby excellent conformity to the shape of a mold is exhibited during tnolding processing
involving heating, spreading, and compressing, the denseness is satisfactorily maintained even
if the tnoltilayer nonwoven fabric is stretched, reduction in thickness is prevented even if the
tnultilayer nonwovetl fabric is subjected to thermal compression in the thickness direction,
and reinforcing effects can be obtained after the multilayer nonwoven fabric is shaped to the
mold. According to this constitution, the multilayer nonwoven fabric exhibits excellent
flexibility after being shaped to the mold, can be formed into complicated shapes, can be
advantageously processed into a shape suitable for a tnold and the like for a foatn molded
body without cutting or while saving the labor associated with cntting, and exhibits excellent
coinfot-tableness when used in a chair and the like. Moreover, the above co~istitutione nables
to maintain sufficient denseness throughout the mnltila)~eel: Thus, when urethane is foamed
on the tnttltilayer nonwoven fabric for foatn molding according to the invention, penetration
(leakage or oozing) of a foaming resin liqnid involving urethane can be advantageously
prevented.
LO0371 A urethane-foam molded complex according to the invention is fortiled by providing
a tirethane foam layer on an outer surface of the reinforcing layer of the above multilayer
nonwoven fabric for foam molding. It is preferable that the reinforcing layer and the
urethane foam layer are formed integrally. When the urethane-foatn molded cotnplex is
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produccd using the multilayer nonwoven fabric for foam molding according to the invention,
the moltilayer advantageously confonns to a desired shape of a metal mold, and the i~rethane
foam layer can be advantageously formed on the multilayer while preveliting the leakage of
urethane.
[0038] In the urethane-foam molded complex according to the invention, since urethane is
prevented from leaking toward a moltilayer nonwoven fabric which is a base fabric, when the
urethane-foam molded complex is used in tnam~facturinga utomobile seats, unusual noises
caused by friction between metal components and urethane foam can be effectively prevented,
and since the flexibility of a non\troven fabric is satisfactorily maintained, riding
comfo~-tableness(s itting comfol-tableness) can be enhanced.
[0039] In a method of producing a nioltilayer nonwoven fabric for foam molding according
to the invention, the reit~forcingla yer is provided on at least one side of the dense layer, and
then the reinforcing layer and the dense layer are entangled with each other by needle
punching. According to the production method of the iover~tiona, multila)rer nonwoven
fabric for foam lnolding having the above explained excellent characteristics can be
advantageously produced.
Hereinafiet; the invention will be described specifically.
[0040]
A multilayer nonwoven fabric for foam molding according to the invention contains
a dense layel; and a reinforcing layer provided on at least one side of the dense layer, the
reinforcing layer is a staple fiber nonnroven fabric containing tl~ern~oplastriecs in staple fibers
(A) having a fiber diameter of more than 20 kun, in an amount of 5% by mass to 50% by mass,
and therlnoplastic resin staple fibers (B) having a fiber diameter of 20 ptn or less, in an
amount of 95% by mass to 50% by mass, a total of the ther~noplasticre sin staple fibers (A)
and the thermoplastic resin staple fibers (B) is 100% by mass, the therlnoplastic resin staple
fibers (A) or the thennoplastic resin staple fibers (B) contain cot~jogatep olyester-based staple
fibers (C) formed containing two or more resins having different melting points, and the
conjagate polyester-based staple fibers (C) are contained in the reinforcing layer in an amount
of 10% by mass to 40% by mass, the dense layer is a nonwoven fabric having bulk density in
a range of fro111 0.05 g/cm3 to 0.3 g/c~n3a,n d the dense layer is preferably constituted of
continuous fibers.
[0041] In the present invention, the tern1 "staple fiber" iudicates fibers having an average
fiber length of about 200 mm or less. Meanwhile, the term "continoous fiber" indicates
"continuous filatnent" generallp used in this technical field, such as "The nonwoven Fabrics
Handbook (INDA, Association of the Nonwoven Fabrics Industry, Japan Nonwo\rens Report,
8
1996).
[0042] A fiber diameter refers to a value obtained by the following method.
Ten sanlples of 10 inm x 10 inm are obtained from a resultant nonwoven fabric, and
the diameter of fibers is read to the first decimal place in the nnit of prn at a inagnification
ratio of 20 using Nikon ECLIPSE E400 microscope. The diameters at arbitrary 30 points are
measured for each sample to obtain an average valne. When fibers are thin (e.g., a
~neltblown layer), a sample piece is obtained Eon1 a resultant nonwoven fabric, tlie sample
piece is observed at a magnification ratio of 500 or 1000 using a scanning electron
microscope, and the fiber diameters (pm) of 30 constituent fibers are measured to obtain an
average value.
[0043] In this specification, "tliem~oplastic resin staple fibers (A) having a fiber diameter of
more than 20 pm" are also referred to as "thennoplastic resin staple fibers of (A)",
"themloplastic resin staple fibers (B) having a fiber diameter of20 pm or less" are also
refelred to as "ther~noplastic resin staple fibers of (B)", and "cor~jugate polyester-based staple
fibers (C) formed containing two or more resins having different melting points" are also
referred to as "conjugate polyester-based staple fibers of (C)".
[0044] (Reinforcing Layer)
The reinforcing layer constituting the moltilayer nonwoven fabric for foarll molding
according to the invention is a staple fiber nonwoven fabric containing thermoplastic resin
staple fibers (A) having a fiber diameter of more than 20 pm, in an amount of 5% by mass to
50% by mass, and thermoplastic resin staple fibers (B) having a fiber diameter of 20 pm or
less, in an aa~ounot f 95% by niass to 50% by mass, a total of the tl~ermoplasticr esin staple
fibers (A) and the thennoplastic resin staple fibers (B) is 100% by mass, tlie thermoplastic
resin staple fibers (A) or the thennoplastic resin staple fibers (B) contain conjugate
polyester-based staple fibers (C) formed containing 6\10 or more resins having different
melting points, and the conjugate polyester-based staple fibers (C) are contained in the
reinforcing layer in an amount of 10% by mass to 40% by mass.
[0045] In view of the shape retention properties of the nonwoven fabric after being shaped
to a mold during molding processing, conjugate polyester-based staple fibers (C) formed
containing two or more resins having different melting points are used in the reinforcing layer.
As a resin which fom~tsh e conjugate polyester-based staple fibers of (C), polyethylene
terepl~thalatei s preferably contained, and polyethylene may be fi~rtliecr ontained. When the
conjugate polyester-based staple fibers of (C) are formed containing polyethylene
terephthalate and polyethylene, it is preferable that the melting point of polyetl~ylene is lower
than that of polyetl~ylenc terephthalate.
[0046] The co~~jugaptco lyester-based staple fibers of( C) in the invention may be either
conjogate fibers formed of two or inorc polyesters having different melting points or
conjugate fibers formed of one or more polyesters and a resin which is other than polyesters
and has a melting point different fiom that o f the polyester resin. More specifically,
sheath-core co~ljugatefi bers includit~ga high-111elting-pointp olyethylene terephthalate (PET)
resin and a low-melting-point PET resin and sheath-core conjugate fibers including a
high-melting-point PET resin and a low-melting-point polyethylene (PE) resin are
exemplified.
[0047] The melting point ofa t least one resin which for~nsth e conjugate polyester-based
staple fibers of (C) is preferably it1 a range of fiom I1O0C to 190°C, more preferably fiom
110°C to 140°C, and still more preferably frotom 110°C to 120°C. It is preferable that the
resin having a melting point of from 110°C to 190°C is a resin having the lowest melting
point (lowv-meltitlg-point resin) among the resins which form conjugate polyester-based staple
fibers.
[0048] The content of the low-melting-point resin in the conjugate polyester-based staple
fibets o f (C) is preferably 10% by tnass to 50% by mass, Inore preferably 20% by Inass to
40 %by mass, and still more preferably 25% by Inass to 35% by tnass.
100491 The content o f the conjugate polyester-based staple fibers o f (C) in a reinforcing
layer influences the shape retention propetties after a nonwoven fabric is shaped to a mold
and flexibility and thickness o f the nonwoven fabric. The reinforcing layer according to the
invention contains 10% by Inass to 40% by Inass oft he co~~jugaptoel yester-based staple
fibers of (C). I f the content of the cot~jugatep olyester-based staple fibers of (C) is less than
10% by mass, although the flexibility and thickness of a non\voven fabric after the nonwoven
fabric is shaped to a mold are suficient, adhesion behveen fibers is insufficient to cause a
deficiency in the shape retention properties to a mold. I f the content ofthe conjugate
polyester-based staple fibers of (C) is more that1 40% by mass, although the shape retention
properties to a mold is sufficient, the adhesion between fibers becomes excessive, and a
nonwoven fabric becomes hard, so that flexibility is impaired. Moreovel; a thickness of a
portion compressed in a thickness ditection during heating, spreading, and compressing
processing is extremely reduced, and it is not preferable because this portion causes leakage
of urethane during urethane foaming processing. More preferably, the reinforcing layer
contains the conjugate polyester-based staple fibers of (C) it1 an amount of 20% by tnass to
35% by tnass.
[0050] The fiber diameter orthe conjugate polyester-based staple fibers of (C) is not
10
particularly limited, and the conjugate polyester-based staple fibers o f (C) having a fiber
diameter of 10 pen to 30 bun may be used, and in view ofeffectively increasing the number o f
adhesive points between fibers during heating, spreading, and compressing processing and
well balancing the shape retention properties and the flexibility, the fiber diameter of at least a
portion ofthe conjugate polyester-based staple fibers of (C) is preferably 20 p111 or Icss, more
preferably 18 tun or less, still more preferably 17 p111 or less, and pa~ticularly preferably 15
11ol or less.
When the conjugate polyester-based staple fibers of (C) include fibers having a fiber
diameter of 20 pm or less, the fiber diameters o f all the conjugate polyester-based staple
fibers of (C) may be 20 pm or less, or the co~~jogaptoel yester-based staple fibers of (C) may
be in the form of mixed fibers further incloding conjugate polyester-based staple fibers having
a fiber diameter of more than 20 pm. The rate of the conjugate polyester-based staple fibers
having a fiber diameter o f 20 ptn or less o f the total mass of the conjugate polyester-based
staple fibers o f( C) is not particularly limited, and the content ratio oft he ther~~loplastriecs in
staple fibers o f (A) and the thermoplastic resin staple fibers o f (B) can be suitably adjusted as
long as it satisfies the range of the present invention.
[0051] The reinforcing layer according to the present invention contains the thermoplastic
resin staple fibers (A) having a fiber diameter o f more than 20 pm and thermoplastic resin
staple fibers (B) having a fiber diameter of 20 ptn or less, and the total ofthe thermoplastic
resin staple fibers o f ( A ) and the thermoplastic resin staple fibers of (B) is 100% by mass.
[0052] The content of the thermoplastic resin staple fibers o f (A) in the reinforcing layer is
5% by mass to 50% by mass. The content ofthe tl~ennoplasticre sin staple fibers o f( A)
influences a thickness o f a nonwoven fabric after the nonwvoven fabric is shaped to a mold.
When the content ofthe thermoplastic resin staple fibers of (A) in the reinforcing layer is in
the above range, sufficient thickness is ensured, and reduction in thickness can be easily
prevented even i f a nollwoven fabric is subjected to thermal compression in the thickness
direction. I f the content of the thermoplastic resin staple fibers o f (A) is more than 50% by
mass, although the thickness of a nonwoven fabric is satisfactorily ensured, a gap ofthe
reinforcing layer becomes too large, thus impairing the strength, urethane leaks when the
orethane is foamed on the reinforcing layer, or urethane reit~forcinge ffectsa re reduced, and
thus it is not preferable. I f the content of the tllermoplastic resin staple fibers o f (A) is less
that1 5% by mass, altl~ougtlh~e strength as the reinforcing layer tends to be high, the thickness
of a nonwoven fabric is excessively reduced to cause a deficiency in flexibility, or urethane
leakage is apt to occur when urethane is foamed on the reinforcing layer, and thus it is not
preferable. In the reinforcing layer, the content ofthe thermoplastic resin staple fibers of (A)
is more preferably 10% by mass to 45% by Illass and still tnore preferably 15% by mass to
40% by inass.
[0053] The fiber diameter ofthe thenuoplastic resin staple fibers of (A) is not partic~~la~.ly
limited as long as it is more than 20 Lun, and the fiber diameter is preferably 23 ptn or more
and more preferably 25 pm or more. The upper limit of the fiber diameter of the
thermoplastic resin staple fibers of (A) is preferably approximately 45 pm in consideration of
flexibility of a resultant nonwoven fabric and entangling fi~t~ctiowni th other fibers of a
reinforcing layer. The upper limit ofthe fiber diameter ofthe thermoplastic resin staple
fibers of (A) is more preferably 39 Lun.
[0054] The thennoplastic resin staple fibers of (A) may include as a part thereofthe
conjugate polyester-based staple fibers of (C).
[0055] The content ofthe thermoplastic resin staple fibers of (B) in the reinforcing layer is
50% by mass to 95% by mass, preferably 50% by tnass to 70% by mass, and more preferably
50% by mass to 65% by tnass. When the above composition ratio is satisfied, staple fibers
having a small fiber diameter are suitably included, so that a gap balance of the reinforcing
layer is optimized. Consequentl): a resultant nonwoven fabric becolnes sofr, and, in addition,
urethane can be prevented from being leaked when the itrethane is foamed. In addition,
suitable nonwoven fabric extensibilitycan be obtained, so that there can be obtained an effect
that conformity to the shape of a mold during heating, spreading, and compressing processing
is improved.
[0056] The fiber diameter ofthe thermoplastic resin staple fibers of (B) is not particolarly
limited as long as it is 20 ptn or less, and the fiber diameter is preferably 18 pm or less, tnore
preferably 17 pm or less, and still tnore preferably 15 Inn or less. The lower limit of the
fiber diameter of the thermoplastic resin staple fibers of (B) is preferably approximately 10
pm in consideration of entangling fimction with other fibers of a reinforcing layer and is more
preferably 12 pm.
[0057] It is preferable that the thermoplastic resin staple fibers of(B) includes as a part
thereof the conjugate polyester-based staple fibers of (C).
[0058] The materials of the thermoplastic resin staple fibers of (A) and the thennoplastic
resin staple fibers of (B) are not patlicularly limited as lorlg as they are themoplastic resins
capable of forming a nonwoven fabric, and various well-known thermoplastic resins may be
used. As thennoplastic resin staple fibers, polyolefin staple fibers formed of
propylene-based polymer and the like, and polyester-basetl staple fibers are preferably used
independently in the tl~ermoplasticre sin staple fibers of (A) and the tl~ermoplasticr esin staple
fibers of (B), and the polyester-based staple fibers are more preferably uscd in view\' of having
thermal stability during heating, spreading, and compressing processing and rigidity against
themla1 compression in a thickness direction.
[0059] It is preferable that the tllermoplastic resin staple fibers of (A) other than the
conjugate polyester-based staple fibers of (C), and the therlnoplastic resin staple fibers of (B)
other tl~anth e cot~jugatep olyester-based staple fibers of (C) are 11igh-melting-point
polyester-based staple fibers having a melting point of nlore than 190°C. If the melting
point is more than 190°C, nlelting of fibers due to heat received during heating, spreading,
and compressing processing is prevented. If fibers are melted, a nonwoven fabric is
hardened, or a thickness of a pollion which has been compressed in a thickness direction is
extren~elyr educed, and it is not preferable because this portion causes leakage of urethane
during urethane foaming.
[0060] Each average fiber length of the conjugate polyester-based staple fibets of (C), the
ther~noplasticre sin staple fibers of (A), and the thernloplastic resin staple fibers of (B) is
usually 200 rnln or less and is preferably in a range of from 10 mm to LOO mm, and more
preferably in a range of from 30 lnnl to 90 mm.
[0061] In the cot~jogatep olyester-based staple fibers of (C), as long as the conjugate
polyester-based staple fibers of (C) is constituted containing hvo or more resins having
different tnelting points, there is no limitation on other configurations, and the conjugate
polyester-based staple fibers of (C) tnay be mixed fibers including hvo or more fibers having
different shapes.
Each of the thertnoplastic resin staple fibers of (A) and the thermoplastic resin staple
fibers of (B) may be mixed fibers obtained by mixing hvo or more fibers soch as mixed fibers
obtained by mixing fibers itlcluding h o or more kinds of different thermoplastic resins and
mixed fibers obtained by [nixing hvo or more kinds of fibers having different shapes.
[0062] The conjugate po1)ester-based staple fibers of (C), the thermoplastic resin staple
fibers of (A), and the thennoplastic resin staple fibers of (B) tnay be side-by-side or
sheath-core conjugate fibers. The cross-sectional shape of the staple fibers may be any of
circular shapes and odd-shapes soch as hollowv shape, V shapes, X shapes, and T shapes.
Crimped fiber or latently crilnpable fibers may be used.
[0063] The staple fibers may be fornled into nonwwfoven fabrics by known methods, and a
preferred method may be mechanical bonding by needle punching, or thermal fitsion bonding.
In order to eficiently stack the nonwoven fabric with a subsequent dense layel; the
reinforcing layer is preferably fornled into the nonwoven fabric by needle punching in
13
advance.
[0064] The bulk density ofthe reinforcing layer is preferably less than or equal to the bulk
density oftllc dense layeel; and although the bulk density of the reinforcing layer is not
particularly limited, the bulk density of the reinforcing layer is osually in the range of ftom
0.01 to 0.1 g/cm3, preferably in the range of from 0.02 g/cm3 to 0.09 g/c1n3, and more
preferably in the range of fiom 0.03 dctn3 to 0.08 g/cm3.
[0065] The basis weight of the reinforcing layer is usually in the range of from 40 g/m2 to
180 g/m2, preferably in the range of from 40 g/m2 to 160 dm2, more preferably in the range of
from 40 g/m2 to 150 g/m2, still more preferably in the range of from 45 g/inz to 130 g/m2, and
particularly preferably in the range of from 50 g/m2 to 100 g/m2.
[0066] The reinforcing layer may be composed of a single layel; or two or more layers.
Whet1 the reinforcing layer is a multilayer oftwo or more layers, the reinforcing layer may be
constituted of the same or different nonwoven fabrics. When the reinforcing layer is
constituted of hvo or more layers of nonwoven fabrics, the non\voven fabrics may be layered
beforehand and entangled or bonded with each other by a kno\vn method, or the nonwoven
fabrics tnay be collectively provided as the reinforcing layer to foml the tnultilayer non\troven
fabric for foam tnolding when the multilayer non\voven fabric for foam molding is produced.
to0671 Specific examples of the polyesters constituting the conjugate polyester-based staple
fibers of (C) include polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT),
polybutylene terephthalate (PBT), polylactic acid (PLA), copolymers of these polymers, and
combination of these polymers. In view of molding properties, such polyesters as
polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), and polybutylene
terephthalate (PBT) are no re preferable. When the thern~oplasticre sin staple fibers of (A)
and the thermoplastic resin staple fibers of (B) are constituted of polyesters, as the polyesters,
the above mentioned polyesters can be exemplified. Preferred polyesters are similar to those
mentiotled above.
[0068] Various \+ill-kno\vn additives may be added to the resins which form the
thermoplastic resin staple fibers of(A), the thennoplastic resin staple fibers of (B), and the
conjugate polyester-based staple fibers of (C), as long as the object of the invention is not
impaired. Examples of such additives include antioxidants, \\feather stabilizers, light
stabilizers, antiblocking agents, lubricants, nucleating agents, pigments, softeners, hydrophilic
agents, auxiliaries, water repellents, fillers, antibacterial agents, flame retardants, deodorants,
and adsorbents. Those additives may be added to the surface of fibers after the formation of
nonwoven fabrics by rnetllods such as spraying.
[0069] The reinforcing layer according to the invention may be provided on only one side or
14
on both sides of the dense layer.
[0070] (Dense layer)
The dense layer constituting the tnultilayer nonwoven fabric for foam molding
according to the invention is a nonwoven fabric whose bulk density is in a range of fro111 0.05
g/cm3 to 0.3 g/cm3 and is preferably fomled of continuous fibers. In the invetltion, when
heat of approximately 180°C is applied during molding processing involving heating,
spreading, and compressing, in tertns of heat resistance, the fibers constituting the dense layer
is preferably polyolefin-based fibers formed of propyletle-based poly~uera nd the like, or
polyestes-based fibers. More prefessed are polyester-based fibers in terms of heat resistance
stability. However, if the temperature of heat applied during molding processing is up to
approximately 1 1O0C, polyolefin-based fibers fortned of propylene-based polymer and the
, like are Inore preferably used in terms of flexibility and productivity. The fiben constituting
the dense layer may be fortned of polymers other than polyolefin-based fibers and a
polyester-based polytner.
[0071] In the dense layel; polytners which fort11 the fibers are not particularly limited as long
as they can form nonwoven fabrics, and various well-known tl~ennoplasticr esins tnay be used.
Specific examples of the polymers include polyolefins such as polyptupylenes (propylene
homopolymers), polypropylene random copolymets, poly(1-butene),
poly(4-tnethyl-1-pentene), ethylenelpropylene random copolymers, ethylenell-butene random
copolytners and propyle~lell-butener andom copolytners, polyesters (such as polyethylene
terephthalate, polybutylene terephthalate, and polyethylene naphthalate), polyamides (such as
nylon-6, nylon-66, and polytnethaxyleneadipamide), polyvinyl chloride, polyitnides,
ethylenelvinyl acetate copolymers, ethylenelvinyl acetatelvinyl alcohol copolymers,
ethylenel(meth)acrylic acid copolymers, etl~ylenelacrylatelcarbon tnonoxide copolymers,
pol~~acr~~lonitrpiolelysc, arbonates, polystyrenes, ionomers, and mixti~reso f these resitls.
[0072] Among these thertnoplastic resins, polyolefins are preferable in tertns of spinning
stability during molding as well as processabilit): air permeability, flexibility, lighhveight and
heat resistance of the nonwovett fabrics, propylene-based polymers are tnore preferable, and
polypropylene or polypropylene randorn copolytners are still more preferable.
[0073] Prefemed propylene-based polytners include homopolymers of propylene having a
melting point (Ttn) of 125°C or more, preferably in a range of ftom 130°C to 165°C and
copolytners of propylene as a main component with one or two or more u-olefins having a
carbon namber of 2 or tnore (except for 3), preferably 2 to 8 (except for 3), such as ethylene,
I-butene, I-pentene, 1-hexene, I -octene, and 4-tnethyl-1-pentene.
[0074] TIte melt flow rate (MFR: ASTM D-1238, 23OoC, 2160 g load) ofthe
15
propylenc-based polymer is not particularly limited as long as the polynler call be tnclt spun.
Wllen the plapylcne-based polymer is used in the meltblo\\~n non\voven fabric, the melt flow
rate thereof is usually in the range of from I0 g/10 min to 3000 g/IO min, preferably in the
range of fi.om 50 g/IO min to 2000 g/l0 min, and more preferably in the range of from I00
g/10 nlin to 1000 g/IO tnin. When the polymer is used in the spunbonded nonwoven fabrics
or the reinforcing layel; the melt flow rate thereof is usually in tlle range of fro111 1 g/10 inin to
500 g/lO min, preferably in the range of frorn 5 g/LO mi11 to 200 g/10 min, and tnole
preferably in the range of from 10 g/10 min to 100 g/10 min.
[0075] The thermoplastic resins according to the present invention may contain various
well-kno\vn additives, as long as the object of the invention is not impaired. Examples of
the additives include antioxidants, weather stabilizers, light stabilizers, antiblocking agents,
lubricants, nucleating agents, pigments, sofieners, hydrophilic agents, auxiliaries, water
repellants, fillers, antibacterial agents, flame retardants, deodorants, and adsorbents.
[0076] The bulk density of the dense layer is in the range of fiom 0.05 g/ctn3 to 0.3 g/cm3,
and preferably in the range of fiotn 0.05 g/cm3 to 0.15 g/ctn3. If the bulk density of the
dense layer is in the above range, the denseness of fibers can be maintained even after the
entanglement and thos being effective for preventing the leakage of urethane, and thus it is
preferable.
[0077] The basis weight of the dense layer is usually in the range of from 10 g/m2 to 60 g/m2,
preferably in the range of h t n 10 gltn2 to 35 g/1n2, and more preferably in the range of fiom
I0 g/ln2 to 25 g/m2. If the basis weight of the dense layer is 10 g/cm2 or more, strength is
enhanced, and haltdleability is excellent even after the reinforcing layer is provided on the
dense layer. If the basis weight is 60 g/n12 or less, a lightweight effect cat1 be obtained, and,
in addition, the nonwoven fabric is easily stretched while being heated, spread, or compressed
to conform to the shape of a mold.
[0078] The air permeability of the dense layer is preferably in the range of from 50
~ m ~ / c n ~ ~to/ s3eUc0 cm3/cm2/sec,I nore preferably in the range of fiom 50 cm3/cm2/sect o 250
cm3/ccn2/sec,a nd still more preferably in the range of from 70 etn3/cmn2/sect o 200
cm3/c~n2/sec. If the air permeability of the dense layer is in the above range, the denseness
of fibers can be maintained after the reinforcing layer is provided on the dense layer, and the
perfonna~lceo f preventing urethane leakage is good. Moreovel; since a urethane foam layer
can be accordingly densely fanned, it is effective for enhancement of rigidity of foams.
[0079] It is preferable that the dense layer includes a nonwoven fabric which is partially
therlnocompression-bonded, air through processed, resin bonded, or calendered, it is snore
preferable that the dense layer is partially thern~ocompression-bonded and embossed. In the
I6
invention, the term "partially" indicates an area ratio in tlie range of from 5% to 30% and
preferably in the range of from 5% to 20%.
[0080] The dense layer niap further include a nonwoven fabric which has not been subjected
to the process of partial tliemioco~~~pression-bondianirg ,t hrough processing, resin bonding,
or calender processing. Alternatively, the dense layer may include a plurality of nonwoven
fabrics each of the nonwoven fabrics has been subjected to these processings.
[0081] It is preferable that the dense layer satisfies the above described bulk density, basis
weight, and air permeability, and various \\rell-known nonwoven fabrics map be used, and
examples of the nonwoven fabrics include spunbonded nonwoven fabrics, fneltblown
nonwoven fabrics, \vet-laid nonwoven fabrics, dry-laid nonwoven fabrics, air-laid pulp
nonwoven fabrics, flash-spun nonwoven fabrics, and spread-fiber non\voven fabrics.
Among those non\voven fabrics, in view of simultaneously realizing the strength and
lightweight of a resultant multilayer nonwoven fabric for foam molding, preferred is
spunbonded nonwoven fabrics or spunbondedlnieltblown tlonwoven fabrics (SM(S)) in which
the dense layer is formed by providing a spunbonded nonwoven fabric layer (S) on at least
one side of a meltblown nonwoven fabric layer (M), and the tneltblown nonwoven fabric
layer and the spunbonded nonwoven fabric layer are partially thermocorupression-bonded.
In tenns of obtaining suitable strength and air permeability while realizing the lightweight,
more preferred is SMS nonwoven fabrics in which the spunbonded nonwoven fabric layers
(S) are provided on both sides ofthe meltblown nonwvoven fabric layer (M), and the
tneltblown tionwoven fabric layer (M) and the the spunbonded nonwoven fabric layers (S) are
paltially thennocompression-bonded with each other.
[0082] The dense layer may be constitnted of one sheet of SMS nonwoven fabrics which is
pattially ther~~~ocompression-bondeaidr, through processed, resin bonded, or calendered, or
may be a ~nultilayerin cluding a plurality sheets of SMS nonwoven fabrics in which each SMS
nonwoven fabrics is partially thermocotnpression-bonded, air through processed, resin bonded,
or calendered.
[0083] The meltblown nontvoven fabric layer (M) suitable in the invention is a nonwoven
fabric layer formed of the above ~nentionedth ermoplastic resin, and the fiber diameter is
usually in the range of fio~n0 .1 pin to 5 pm and preferably in the range of from 0.5 Itrn to 3
bun, and the basis weight is in the range of fiom 0.1 g/m2 to 5 g/m2 and preferably in the range
of frotn 1 glm2 to 3 g/rn2.
[0084] If the fiber diameter and the basis weight of the meltblown nonwoven fabric layer
(M) are in the above ranges, when it is used as a dense layel; leakage of urethane can be
effectively prevented. At the same time, when the dense layer arid a substrate layer are
17
bonded \\lit11 each other by needle poncliing, the fibers of the meltblown non\\'oven fabric
layer (M) is hardly cut by a needle, and, in addition, the weight of a resultant tnultilayer
nonwoven fabric for foam molding call be reduced.
[0085] The spunbonded nonwoven fabric layer (S) suitable in the invention is a nonwoven
fabric layer formed ofthe above thermoplastic resin, and the fiber diameter is usually in the
range of from 10 pm to 40 pm and preferably in the range of from I0 pm to 20 ptn, a~idth e
basis weight is in the range of from 5 glm2 to 25 g/~nZan d preferably in tlie range of from 5
glm2 to 10 dm2.
[0086] Ifthe fiber diameter and tlie basis weight of the spunbonded nonwoven fabric layer
(S) are in the above ranges, \\~hent he dense layer and the reinforcing layer are bo~idedw ith
each other by needle punching, the fibers ofthe dense layer and the fibers of the reinforcing
layer cat1 be toughly entangled with each othel; and, at the saliie time, the lightweight and
strength oftbe multilayer nonwoven fabric for foam moldi~igc an be si~nultaneouslyr ealized,
and leakage of urethane can be effectively prevented.
[0087] The spunbondedl~~~eltblonwon\ voven fabrics (SM(S)) are produced by a
co~nbitlationo f a method of producing various well-known meltblown nonwoven fabric and a
method of pladuci~iga spunbonded t~on\\~ovefnab ric.
[OOSS] Specifically, for example, beforehand, the above thermoplastic resin is spun from
spinneret nozzles, and the continuous fiber filaments that have been spun are quenched with a
cooling fluid and are atte~iuatedto a desired fineness by applying a tension to the filaments by
stretching air. The resultant filaments are then collected on a moving collectio~b~el t to
obtain a spunbonded ionw wove^^ fabric layer (S). Thereafter, the thennoplastic resin is
melted and extruded on the spunbonded nonwoven fabric layer (S), and fibers spun from a
t~ieltblowings pinneret are spun as an ultrafine fiber stream by a high-temperatul.e and
high-speed gas. The stream of the ultrafine fibers are formed into an ultrafine fiber web by a
collectio~id evice, and a meltblown nonwoven fabric layer (M) is fomied. Subsequently,
another spunbo~idedn onwoven fabric layer (S) is provided onto the ~~ieltblownno nwoven
fabric layer (M), followed by partial thermocompression-bonding, whereby the
spunbondedl~neltblown nonwoven fabrics (SMS) can be produced.
[0089] The dense layer (in particulat; the tneltblown nonwoven fabric layer (M) and tlie
spunbonded nonwoven fabric layer (S)) is partially thermocotnpressio~i-botideda, ir through
processed, resin bonded, or calendered, and various well-known methods can be adopted as
these processing methods. Particularly, \vheti the dense layer is partially
thermocompression-bonded by embossing or the like, the bulk density of a resultant dense
layer is easily adjusted in the above range, and the strength and rigidity of the dense layer are
IS
i~nplvvedt,h e dense layer does not sag and can be easily attached to a mold to achieve an
improvement in \\lorking speed. Further, embossing is preferable also in vie\v of the
prevention ofthe passage of a resin liquid for foam molding containing urethane.
[0090] When the tl~ennocompression-bondi~ilsg p erforined by hot embossing, the
embossing area ratio is usnally in the range of fronl 5% to 30% and preferably in the range of
frotn 5% to 20%. Examples of embossing shapes include circle shapes, ellipticat shapes,
oval shapes, square shapes, rhombic shapes, rectangular shapes, quadrangular shapes, quilt
shapes, grid shapes, tottoiseshell shapes, and continuous shapes based on these shapes.
[0091] In general, since the fiber diameter of the fibers which form the spunbonded
nonwoven fabric layer (S) is larger than the fiber diameter of the fibers which fortn the
lneltblown non\\loven fabric layer (M), it is preferable that in the dense layer according to the
invention, the spnnbonded non\\roven fabric layer (S) is provided on both sides (both surfaces)
of the meltblown nonwoven fabric layer (M). According to this constitution, the
spunbonded nonwoven fabric layer (S) more effectively serves to reinforce the meltblown
nonwoven fabric layer (M).
[0092] The dense layer may be constituted of one layer of nonwoven fabrics, or [nay be
constituted of two or more layers of nonwoven fabrics. When the dense layer is constituted
of hvo or more layers of nonwoven fabrics, the nonwoven fabrics may be the same or
different from one another. When the dense layer is constituted ofhvo or more layers of
nonwoven fabrics, the nonwoven fabrics may be layered beforehand and entangled or bonded
with each other by a known method, or the nonwoven fabrics tnay be collectively provided as
the dense layer to fonn the multilayer nonwoven fabric for foatn molding when the multilayer
non\voven fabric for foam tnolding is produced.
[0093] (Moltilayer nonwoven fabric for foal11 molding)
The tnultilayer nonwoven fabric for foam molding according to the invention is
formed by providing a reinforcing layer on at least one side of a dense layer, and the dense
layer and the reinforcing layer are entangled with each other by needle punching.
[0094] The multilayer nonwoven fabric for foal11 ~uoldinga ccording to the invention is
fornled by providing the reinforcing layer on at least one side of the dense layet; preferably on
both sides of the dense layer. The dense layer usually has a bulk density 11igher than that of
the reinforcing layel: When the reinforcing layer is provided on only one side of the dense
layer, a foam molded body such as a urethane foan~la yer is formed on the surface on which
the reinforcing layer is provided.
[0095] In order to ensure fabric extensibility as a mitltilayer nonwoven fabric \\then the
nonwoven fabric is shaped to a inold, thickness after finishing, and flexibility, it is preferable
19
that the reinforcing layer is a main constituent of the multilayer nonwoven fabric, and the
dense layer is suppressed to a necessity minimum, and it is preferable that each basis ~veight
and configuration of the reinforcing layer and the dense layer are in the above ranges.
[0096] 'The basis weight as the moltilayer nonwoven fabric for foam molding is preferably in
the range of fro111 20 g / ~t~o ~1620 g /~n2m, ore preferably in the range of from 40 dm2t o 140
g/m2, and still more preferably it1 the range of fiotn 50 g/m2 to 120 g/~n2. If the basis weigllt
of the multilayer nonwoven fabric for foam molding is 20 g/tn2 or more, the strength is
sufficietlt, handleability is excellent, and, in addition, the thickness is sufficient, so that
urethane leakage can be easily prevented. If the basis weight of the inultilayer nonwoven
fabric for foam molding is 160 g/m2 or less, an excellent lightweiiglt property is exhibited,
and the nonwoven fabric is easily stretched \vIlile being shaped to a mold.
[0097] In the moltilayer nonwoven fabric for foam molding according to the invention, in
order to ensure thickness in view of ensuring urethane leakage prevention and flexibilit): wen
if entangling processing by needle punching is nteakened, the strength as the tnultilayer is
maintained well as compared with a moltilayer nonwoven fabric for foatn tnolding constituted
of only a reinforcing layer. The thickness ofthe multilayer nonwoven fabric for foatn
tnolditlg accorditlg to the invention is preferably 1.6 mm to 5.0 mm and more preferably 2.0
mm to 4.5 mm. If the thickness of the multilayer non\\roven fabric for foam molding is 1.6
mm or more, there is a tendency that urethane leakage can be fi~tthepr revented, and, in
addition, the tnultilayer non\voven fabric for foam molding is excellent in flexibility of a
notlwoven fabric layer. If the thickness of the multilayer nonwoven fabric for foam tnolding
is 5.0 tnm or less, there is a tendency that the multilayer nonwoven fabric for foam molding is
excellent in conformity to the shape of a mold.
[0098] The moltilayer nonwoven fabric for foatn molding according to the invention is
allowed to have a thickness of the fabric after being held at llO°C and 4.9 Pa for 5 minutes is
1.2 tntn or more. If the thickness ofthe fabric after being held at 110°C and 4.9 Pa for 5
minutes is 1.2 mm or more, the thickness reductiotl can be prevented even if the multila)fer is
subjected to thertnal compression in the thickness direction, and there is an advantage that
leakage during urethane foaming can be prevented. The thickness is more preferably 1.3
tntn or more, still tnore preferably 1.4 mm or tnore, and particularly preferably 1.5 tntn or
more.
[0099] It is preferable that the multilayer nonwoven fabric for foam molding according to
the invention has sufficient denseness to prevent a foamed resin such as urethane kom leaking
at the stage of tnolding the foam lnolded body. It1 addition, it is more preferable for the
tnultilayer that the air permeability is maintained. In the tnaltilayer non\troven fabric for
20
foa~nn molding, the air permeability at a pressure difference of 125 Pa is preferably 20
cm3/cm2/scc to 160 cm3/ctn2/sec, inore preferably from 25 cm3/cm2/sec to 160 cm3/cm2/sec,
still tnore preferably from 25 cm3/ctn2/sec to 140 cm3/c~n2/secp,a rticularly preferably from 30
cm3/cm2/sect o 125 ct~~~/cm~a/nsde cex, treunely preferably froan 30 cm3/ctn2/sect o 115
cm3/cm2/sec, If the air permeability of the tnultilayer nonwoven fabric for foam molding is
in the above range, perfor~nanceo f preventing leakage of a foamed resin such as urethan is
excellent, and, at the same time, a gas generated in the foatn tnolditng can be advantageously
discharged. Moreovel; since a foam layer can be accordingly densely formed, it is effective
for enhancement of rigidity of foams.
[0100] Ful-ther, the multilayer nonwoven fabric for foatn molding according to the invention
has a tensile strength (I4150 mm) of, although not particularly limited to, 30 N or more and
preferably 40 N or tnore. This tensile strength advantageously ensures excellent
handleability.
[0101] The moltilayer nonwoven fabric for foam molding according to the invention may be
used in foam molding in the form of multilayers including additional substrate layers, as long
as the effects of the invention are not impaired.
[0102] Specific exatnples of the additional substrate layers to be provided with the
tnultilayer nonwoven fabric for foam molding according to the invention include knitted
fabrics, woven fabrics, nonwoven fabrics, films, and paper products. As a nnethod of
providing (laminating) the multilayer nonwoven fabric ofthis invention and other layers
together, there can be adopted various well-known methods including thermal fi~sionb onding
methods such as hot embossing and nltrasonic fusion bonding, mechanical entangling
methods such as needle punching and waterjetting, methods using adhesives such as hot melt
adhesives and urethane adhesives, and extrasion latnination.
[0103]
In the method for producing a multilayer nonwoven fabric for foam molding
according to the invention, a reinforcing layer is provided on at least one side of a dense layer,
and the dense layer and the reinforcing layer are then entangled with each other by needle
punching. The multilayer nonwoven fabric for foam molding is fortnned by bonding the
dense layer and the reinforcing layer by various well-known methods, specifically including
thermal fusion bonding methods such as hot embossing and ultrasonic fi~siotnb onding,
mechanical entangling methods such as needle punching and \\later jetting, metliods using
adhesives such as hot nnelt adhesives and urethane adhesives, and extrusion lamination. In
the bonding of the dense layer and the reinforcing layel; an entangling tnethod of
~nechanicallyb onding them by needle punching or a thennal fi~siotnb onding method of fi~sion
21
bonding them by heating treatlncnt may be adopted. ParticolarI>: in this invention, a
mnltilayel. in which the dense laycr and the reinforcing laycr are integrated by entangling by
needle punching is provided. According to this constitution, the dense layer and the
reinforcing layer arc bonded with uniform mechanical entanglement. Moreover, in thickness
and denseness as a inaltilayel; an opti~nabl alance can be maintained by needle punching.
Thas, the multilayer nonwoven fabric for foam nlolding according to the invention does not
interfere with the stage of three-dimensionally following tbe shape of a mold nsed for
producing a foam molded body, suppresses thickness unevenness due to spreading involved
during the following, and can maintain good denseness and flexibility throughout the entirety
thereof. At the same time, a resultant multilayer nonwoven fabric for foam molding
maintains suitable air permeability to allow the passage of a gas generated during foam
molding of urethanes or the like and can control the impregnation with liquids soch as
urethanes to prevent leakage.
[0104] When the layers are bonded (entangled) by needle punching, an oil agent such as a
softener or a slip agent may be kneaded into or applied to the nonwoven fabrics for the
purposes of reducing the probability for the fibers to be cnt during needle pnnching as well as
reducing unusual noises between foams and metal components, as long as the effects of the
invention are not impaired.
[0105] In the multilayer nonwoven fabric for foam molding according to the invention, for
example when a dense layer in which the spunbonded nonwoven fabric layer (S) is provided
on both sides of the ~neltblown nonwoven fabric layer (M) by partial
thermocomp~~ession-bondinisg used, if the dense layer and the reinforcing layer are bonded
with each other by needle punching, the fibers which for111 the spunbonded non\voven fabric
layer (S) and the fibers which form the reinforcing layer are adequately entangled with each
other without fiber breakage, thereby achieving high bonding strength between the dense
layer and the reinforcing layer. In addition, even if the fibers of the meltblown nonw70ven
fabric layer (M) ale cut by needles, there is no risk that the fiber dust will come on the surface
of the multilayer non\\roven fabric for foam molding.
[0106] In the multilayer nonwoven fabric for foam molding according to the invention, the
dense layer and the reinforcing layer are bonded by the needle punching method as described
above, and since the dense layer exercises the effects as a substrate layet; the configoration of
the reinforcing layer can be ficely adjusted in the range as described above. The effects of
the dense layer as a substrate laycr appear as a strength retention effect as a multilayer, a fiber
retention (fall prevention) effect for staple fibers of the reinforcing layel; and a dimension
stabilizing effect as a nulltilayer when the nonwoven fabric confor~nsto the shape of a mold
22
during l~eating/spreading/co~~~prespsrioncge ssing. In comparison with the case of using a
single reinforcing layer (staple fibers), suitable strength and suitable fabric extensibility can
be obtained, and excessive heat shrinkage can be prevented.
[0107] The multilayer nonwoven fabric for foal11 molding according to the invention may be
subjected to secondary processing such as gear processing, printing, coating, lacnination, heat
treatment, ~noldingp rocessing, water-repellent treatment, or hydrophilic treatment, as long as
the effects of the invention are not impaired.
[0108] The multilayer nonwoven fabric for foal11 molding according to the invention is
applicable to any foam molded article, and for exanlple when the multilayer is applied to
foal11 molded atlicles forn~edo f urethane and the like, good rigidity, anti-noise performance,
and riding comfot-tableness can be given thereto. For example, the moltilayer non~\~oven
fabric for foam nlolding according to the invention tnay be applied to the molding of foam
molded articles in various applications including vehicle seats such as auto~nobiles eats,
fitmiture, office chairs and beds.
[0109]
A urethane-foam molded co~nplexa ccording to the invention is obtained by
providing a urethane foam layer on an outer surface of the reinforcing layer of the above
described multilayer nonwoven fabric for foam molding of the invention. It is preferable
that the urethane-foam molded cornplex of the invention is obtained by integrally forming the
reinforcing layer of the n~oltilayern onwoven fabric for foam nlolding of the invention and the
urethane foam layer. The urethane foam layer is usually produced by foam molding
polyurethane it1 a mold having a desired shape. For example, the urethane-foam molded
cotnplex of the iuve~ltionl nay be manufactured by arranging the multilayer nonwoven fabric
for foam molding of the inventio~in~ a mold such as a tnetal mold so as to conform to a
portion such as the top or the botto~ilo f the mold, then pouritlg a polyurethane raw material
including a foaming agent into the a~olda,n d foam molding the polyurethane raw material.
[01101 According to the invention, the tuultilayer nonwoven fabric for foam molding
exhibits excellent confomability to the shape of a mold and can sin~ultaneously realize
sufficient denseness and flexibility tl~roughout he entirety thereof even after it is set in
conformity to the mold. Thus, urethane can be prevented from leaking, polyurethane foams
call be prevented from leaking to a surface, and a urethane-foam molded complex integrated
with a molded body can be manufactored.
[Oil I ] For example, the urethane-foam molded complex according to the invention may be
suitably applied to various applications usiug an urethane foam tllolded body, ir~cluding
vehicle seats in vehicles such as aototnobiles, trains, airplanes, and play equipment, furniture
23
sl~cha s chairs and beds, toys, and buildiclg materials.
[0112] By virtue ofthe use ofthe moltila)ler nonwoven fabrics for foam molding according
to the invention, the orethane-foam molded complex accordillg to the iilvention can be
rnanofactured simply by foam molding 011 the reinforcing materials arranged in molds wvithout
entailing coinplicated processes such as cutting and sewing of the reinforcing materials.
When used in combination with ~netalc omponents or the like as is the case in applicatio~ls
such as vehicle seats, urethane-foam inolded complex provides advantageous effects such as
that the occurrence of unosual noises caused by friction between the rnetal components and
orethane foam can be effectively prevented, and good riding co~nfortableness( sitting
comfo~tableness) can be realized.
[OI 131 The orethane-foam molded co~nplexa ccording to the invention is applicable to any
foam molded article, and for example when urethane-foam molded cotnplex is applied to
foal11 molded articles formed of urethane and the like, good rigidity, anti-noise performance,
and riding cornfo~tableness( sitting comfo~tablenessc) an be given thereto. For example, the
urethane-foam molded complex according to the invention may be applied to the molding of
foam inolded articles in various applications including vehicle seats such as alltomobile seats,
furniture, office chairs and beds.
EXAMPLES
[OI 141 Hereinafter, the present invention will be Inore specifically described based on
examples. I-lowever, the invention is not litnited to the examples.
[0115] Properties in examples and comparative exatnples were measured by the following
methods.
[O 1161 (1) Basis weight (g/ln2)
Ten san~plehs aving a size of 100 tntn in a machine direction (MD) and 100 mm in a
cross direction (CD) were obtained from a nonwoven fabric, and the average of the weights
per unit area thereof was calculated.
[0117] (2) Thickness (mm)
The thickness was measured at ti\re points, namely, the center and the four corners of
the basis wveight measurement samples, and the average thickness of the 50 points was
calculated. Tlle thicktless meter with a load of 2 g/cn~(2lo ad area: 4 cm2) was used.
[OI 181 (3) Bulk density (g/cm3)
The bulk density of the nonwoven fabric was determined from the follow\~ing
equation using the basis \\'eight and the thickness obtained in (1) and (2).
Bulk density= basis weight (g/~1~2)/(thickne(s1sn 111)/10 x 100 x 100)
24
[0119] (4) Tensile strength (N/50 cntn) and elongation (%)
The tensile strcngth arid the elongation were measured in accordance with JIS L1906
(2010). Test pieces of 300 t i u u (MD) x 50 t i u u (CD) were obtained from a multilayer
non\iioven fabric for foam inolding. The test piece was tested \vith a tensile tester
(AUTOGRAPH AGS-J manufactured by Shitnadzu Corporation), by being claniped between
chucks 200 tntn apart from each other, atid was pulled at a head speed of 100 tnmhnin. The
test was performed five times with respect to MD (length direction of the nonwoven fabric),
and five times \writ11 respect to CD (direction perpetldicular to tlie length). The average
values thereof were calculated to obtain the tensile strength atid the elongation.
[0120] (5) Air permeability (cm3/ctn2/sec)
A test piece of200 mtn (MD) x 50 tnm (CD) was obtained from a multilayer
nonwoven fabric for foam molding, and tlie flow rate at a pressure difference of 125 Pa was
measured by a Frazier air permeability tester in accordance with JIS L1096 (2010) to obtain
air peniieability.
[OI 2 I] (6) Molding properties
A 20 cnl square simple mold having a height of 10 cm was covered with a 40 c~ii
square piece (400 tnrn (MD) x 400 tntn (CD)) of a multilayer nonwoven fabric for foam
molding, and the multilayer nonwoven fabric was tnold processed at 200°C wit11 a vacuum
forming machine. Molding properties were evaluated based on visual inspection and feel
(touch) according to the following criteria with respect to items such as the easiness in
molding the multilayer nonwoven fabric to the mold, and the shape retention properties, the
ditner~sions tability, and the texture (flexibility) of the shaped nonwoven fabric.
[0122] AA: Molding was feasible and the multilayer maintained good appearance and
texture required for a reitiforcing lnaterial
A: Molding was feasible and the multilayer was acceptable for use as a reinforcing
material
B: Molding was feasible but the tnultilayer had a poor texture for use as a reinforcing
lnaterial
BB: Molding failed due to problems such as iiielting
[O 1231 (7) Thickness after hot pressing
A 5 kg load was applied to a 10 cm square (100 tntn (MD) x I00 lntn (CD))
nonwoven fabric, and the thickness ofthe nonwoven fabric after being stood in an oven at
I 10°C for 5 minutes was measured.
[0124] (8) Evaluation of orethane leakage
A 40 ctn square piece (400 Inn1 (MD) x 400 inn1 (CD)) of a multilayer nonwoven
fabric for foam molding was attached to a foaming mold, and the occurrence of urethane
leakage was visually evaluated based on the following criteria.
[0125] AA: No leakage
A: Substantially no leakage
B: Slight leakage
BB: Heavy leakage
[0126] Hcre, a polyurethane was used as a resin material, and the foaming mold used was an
autotnobile seat-like mold. The foaming was carried out under usual foanied polyurethane
molding conditions in automobile seats.
[0127] [Example I ]

[0135] The entire disclosore of Japanese Patent Application No. 2013-185735 is
iticol.porated by reference in this specification.
All contents of the documents, patent applications, and technical standards described
in this specification are incorporated herein by reference to the same extent as that when it is
specifically and individually described that tile respective documents, patent applications, and
the technical standards are incorporated herein by reference.
CLAIMS
I . A multilayer nonwoven fabric for foam molding, colnprising:
a dense layer; and
a reinforcing layer provided on at least one side of the dense layel; wherein the
reinforcing layer is a staple fiber nonwoven fabric containing:
thermoplastic resin staple fibers (A) having a fiber diameter of more than 20
pm, in an amount of 5% by mass to 50% by mass, and
thennoplastic resin staple fibers (B) having a fiber diameter of 20 lu11 or less,
in at1 amount of 95% by mass to 50% by mass,
wherein a total of the themloplastic resin staple fibers (A) and the thermoplastic resin
staple fibers (B) is 100% by mass, the ther~noplasticr esin staple fibers (A) or the
thermoplastic resin staple fibers (B) contain cot~jugatep olyester-based staple fibers (C)
formed containing two or Inore resins having different tnelting points, and tlie conjugate
polyester-based staple fibers (C) are contained in the tcinforcing layer in an amount of 10%
by Inass to 40% by mass,
wherein the dense lajrer is a nonwoven fabric having bulk density in a range of from
0.05 g/ctn3 to 0.3 &m3, and
wherein the dense layer and the reit~forcingla yer are entangled with each other by
needle punching.
2. The tllultilayer nonwoven fabric for foam molding according to claim 1, wherein
a thickness of the fabric is fro111 1.6 iutn to 5.0 mtn.
3. The multilayer non\voven fabric for foatn molding according to clainl I or 2,
wherein a thickness of the fabric after being held at 1 10°C and 4.9 Pa for 5 minutes is 1.2 mm
4. The multilayer nonwoven fabric for foatn molding according to any one of
claims I to 3, wherein a fiber diameter of at least a portion of the cot~jugatep olyester-based
staple fibers (C) is 20 ptn or less.
5. The ~nultilayern onwoven fabric for foam molding according to any one of
claims 1 to 4, wherein a melting point of at least one resin that forms the conjugate
polyester-based staple fibers (C) is in a range of fiom 110°C to 190°C.
6. The multilayer non\voven fabric for foal11 tliolding according to any one of
claitns 1 to 5, whereit1 the dense layer includes a nonwoven fabric that is pattially
thermocompression-bonded, air througli processed, resin bonded, or calendered.
7. The multilaycr nonwoven fabric for foatn tnoldirig according to any otle of
claims I to 6, wherein the dense layer is a nonwoven fabric constituted of contim~ousf ibers.
8. The multilayer nonwoven fabric for foam molding according to any one of
claitns 1 to 7, wherein the thermoplastic resin staple fibers (A) and the thertnoplastic resin
staple fibers (B) are at least one kind of staple fibers selected from the group consisting of
polyester-based staple fibers and polyolefin-based staple fibers.
9. The tnultilayer nonwoven fabric for foain tnoldit~ga ccording to any one of
claitns I to 8, \vIiercin the thennoplastic resin staple fibers (A) and the thermoplastic resin
staple fibers (B) are polyester-based staple fibers.
10. The multilayernonwoven fabric for foam tnoldit~ga ccording to any one of
claitns 1 to 9, wherein the dense layer includes a contit~uousfi ber nonwoven fabric that is
partially thermocotnpression-bonded.
I I . The multilayer nonwoven fabric for foam tnolding according to any one of
claitns I to 10, wherein a basis weight of the dense layer is in a range of from 10 g/tn2 to 35
g/n12.
12. The tnultilayer nonwoven fabric for foam molding according to any one of
claitns 1 to 11, wherein an air pertneability of the dense layer is in a range of fiom 70
cm3/cm2/sec to 200 cm3/cm2/sec.
13. The multilayer nonwoven fabric for foam tnolding according to any one of
claitns 1 to 12, wherein the dense layer comprises a nutltilayer structure containing:
a melt-blo~vn nonwoven fabric layer (M) that is constituted of continuous fibers, and
a spllnbonded nonwovetl fabric layer (S) constituted of continuous fibers, and
provided on both sides of the melt-blown nonwoven fabric layer (M); attd
3 1
the melt-blown notiwoven fabric layer (M) and each spunbonded nonwoven fabric
layer (S) are partially tl~crmoco~npression-bonde\vdi th each othcl:
14. The multilayer nonwoven fabric for foam molding according to any one of
claiins 1 to 13, \vherein the multilayer nonwoven fabric has an air permeability at a pressure
difference of 125 Pa of from 25 cm3/cm2/sec to 160 cm3/cm2/sec.
15. The multilayer nonwoven fabric for foam molding according to any one of
claims I to 14, wherein the multilayer nonwoven fabric has a basis weight of fi.011120 g/m2 to
160 g / ~ 2 .
16. The tnultilayer nonwoven fabric for foam molding according to any one of
claims 1 to 15, whereit1 the ~nultilayenr onwoven fabric has an air permeability at a pressure
difference of 125 Pa of 25 cm3/cd/sec to 140 cm3/cm2/sec.
17. The multilayer nonwoven fabric for foal11 molding according to any one o f
claims 1 to 16, wherein a basis weight of the reinforcing layer is in a range of from 40 g/tn2 to
150 g/m2.
18. A method of producing the tnultilayer non\voven fabric for foam tnolding
according to any one of claims I to 17, comprising providing the reinforcing layer on at least
one side of the dense layer, and, subseqitently, entangling the reinforcing layer atid the dense
layer with each other by needle punching.
19. The method of producing the multilayer nonwoven fabric for foam molding
according to claim 18, wherein the dense layer is formed by providing the spunbonded
nonwoven fabric layer (S) on both sides of the meltblown nonwoven fabric layer (M), and,
subsequently, carrying out partial thermocompression-bonding, air through processing, resin
bonding, or calendering.
20. A urethane-foam tnolded colnplex in \vhich a urethane foam layer is provided
on an outer surface of the reinforcing layer of the multilayer nonwoven fabric for foam
molding according to any one of claims 1 to 17.
21. The urethane-foam molded complex according to claim 20, \vhercin the
32
reinforcing layer and the urethane foam layer are integrated with each other,
22. A vehicle seat comprising the multilayer nonwoven fabric for foam molding
according to any one of claims 1 to 17 or the urethane-foam rnolded complex according to
claim 20 or 21.
23. A chair comprising the multilayer nonwoven fabric for foam molding according
to any one of claims 1 to 17 or the urethane-foam molded colnplex according to claim 20 or
21.