SPECIFICATION
BIOMASS-DERIVED POLYESTER STAPLE FIBERS AND WET-LAID
NONWOVEN FABRIC FORMED FROM THE SAME
Technical Field
[000 1]
The present invention provides wet-laid nonwoven fabric usmg
polyalkylene terephthalate staple fibers and/or polyalkylene naphthalate
staple fibers having a biomass-derived carbon ratio of 10% or more and
100% or less by the radioactive carbon measurement (carbon 14, one of
radioisotopes of the carbon atom and has 6 protons and 8 neutrons in the
nucleus. The same applies to the following.), single fiber fineness of
0.000 1 to 7.0 decitex, and a fiber length of 0.1 to 20 mm and a
manufacturing method of the same.
Background Art
[0002]
Recently, the amount used for synthetic fiber paper obtained by a
web forming method using polyethylene terephthalate fibers for a part or
the whole of a material of paper has been increasing owing to its excellent
physical characteristics such as mechanical characteristics, electric
characteristics, heat resistance, dimensional stability, hydrophobic nature
and the like and cost advantages. As a binder fiber used for the synthetic
fiber paper, polyethylene fibers and polyvinyl alcohol fibers were used in
1
the past but polyethylene terephthalate fibers are mainly used at present.
For the synthetic fiber paper mainly using polyethylene terephthalate fibers,
the same kind of polyethylene terephthalate fibers are mainly used as an
optimal binder. Moreover, in recent years, in the fields of heat-retaining
materials, electrical insulating materials, filters, medical materials,
construction materials and the like, a demand for development of wet-laid
nonwoven fabrics having heat resistance has become high. Thus, a
wet-laid nonwoven fabric formed of fibers using polyethylene naphthalate
which is one of polyesters having higher heat resistance as a material has
been developed (See Patent Literature 1, for example).
[0003]
However, depletion of petroleum and wood has become a senous
social problem in recent years, and sustainable development is given
importance. Thus, a wet-laid nonwoven fabric using a polylactic acid fiber
which is a biomass-derived component is proposed (See Patent Literature 2,
for example). However, with such a wet-laid nonwoven fabric, the melting
point of polylactic acid which is a polymer is as low as in the vicinity of
170°C, hydrolyzability is low, and fully satisfactory values of adhesive
strength and heat resistance of the wet-laid nonwoven fabric have not been
obtained.
[0004]
Patent Literature 1: Japanese Unexamined Patent Application
Publication No. 2009-221611
2
Patent Literature 2: Japanese Unexamined Patent Application
Publication No. 2010-180492
Summary of the Invention
Problems to be Solved by the Invention
[0005]
The present invention was made in VIew of the above-described
background and has an object to provide staple fibers that are used suitably
for a wet-laid nonwoven fabric having excellent tensile strength and heat
resistance while reducing an environmental burden, a wet-laid nonwoven
fabric and a manufacturing method of the wet-laid nonwoven fiber.
Means for Solving the Problems
[0006]
As the result of keen studies in order to achieve the above object,
the present inventors have invented fully oriented staple fibers and low
oriented staple fibers having specific biomass-derived carbon ratio, fineness,
and fiber length. Moreover, the inventors have found out that a
polyalkylene terephthalate staple fiber wet-laid nonwoven fabric or
polyalkylene naphthalate staple fiber wet-laid nonwoven fabric having
excellent adhesive strength and heat resistance can be manufactured by
using the fully oriented staple fibers and the low oriented staple fibers at a
specific weight ratio. Furthermore, the inventors have found out that,
since the low oriented staple fibers are fine low oriented staple fibers
3
having excellent binder performance, that is, thermal adhesiveness, the
wet-laid nonwoven fabric can be manufactured by a manufacturing method
of blending and thermal-compression bonding the fine fully oriented staple
fibers and these fine low oriented staple fibers and reached the series of
inventions in the present application.
[0007]
That is, one invention of the present application is polyalkylene
terephthalate staple fibers III which a biomass-derived carbon ratio by
radioactive carbon (carbon 14) measurement IS 10% or more and 100% or
less, single fiber fineness is 0.0001 to 7.0 decitex, and a fiber length is 0.1
to 20 mm or polyalkylene naphthalate staple fibers III which a
biomass-derived carbon ratio by radioactive carbon (carbon 14)
measurement IS 10% or more and 100% or less, single fiber fineness is
0.0001 to 7.0 decitex, and a fiber length IS 0.1 to 20 mm. Another
invention of the present application is a wet-laid nonwoven fabric
containing the polyalkylene terephthalate low oriented staple fibers or
polyalkylene naphthalate low oriented staple fibers satisfying the matters
presented above by 15 mass% or more or a wet-laid nonwoven fabric
composed only of one or two types or more of polyalkylene terephthalate
staple fibers or one or two types or more of polyalkylene naphthalate staple
fibers satisfying the matters presented above and containing the
above-described low oriented staple fibers by 15 mass% or more. Still
another invention of the present application is a manufacturing method of a
wet-laid nonwoven fabric in which fully oriented staple fibers (A) and low
4
oriented staple fibers (B) are mixed and subjected to web forming and then,
subjected to heat treatment by a drum dryer or an air-through dryer and
further to the heat treatment by a calender roll as necessary.
Advantageous effects of the Invention
[0008]
According to the present invention, compared with wet-laid
nonwoven fabrics made of polyethylene terephthalate and polylactic acid
which have been examined, a polyalkylene terephthalate staple fiber
wet-laid nonwoven fabric or a polyalkylene naphthalate staple fiber
wet-laid nonwoven fabric having excellent tensile strength and heat
resistance and a reduced environmental burden can be provided. Those
wet-laid nonwoven fabrics are suitably used for applications such as bag
filters, electrical insulating material of F class or above in heat resistance
class, separators for batteries, separators for capacitor (super capacitor),
ceiling materials, floor mats, engine filters, oil filters and the like.
Moreover, wide applications to nonwoven fabric materials for vehicle
requiring heat resistance and chemical resistance are expected.
Best Mode for Carrying Out the Invention
[0009]
An embodiment of the present invention will be described below in
detail.
5
Polyalkylene terephthalate constituting polyalkylene terephthalate
staple fibers of the present invention comprises alkylene glycol and
terephthalic acid as main constituent components. The main constituent
component means that a repeating unit of polyalkylene terephthalate is 80
mol% or more of the total. As alkylene glycol, linear alkylene glycols
having 2 to 10 carbon atoms can be cited or preferably a linear alkylene
glycol having 2 to 6 carbon atoms. Specifically, ethylene glycol,
trimethylene glycol, tetramethylene glycol, hexamethylene glycol,
octamethylene glycol or decamethylene glycol can be cited. Moreover,
other monomer components can be copolymerized as long as physical
characteristics of polyalkylene terephthalate are not lost, but they are
preferably copolymerized so that the repeating unit of polyalkylene
terephthalate becomes 80 mol% or more. Acid components capable of
copolymerization include aromatic dicarboxylic acid other than terephthalic
acid, aliphatic dicarboxylic acid, alicyclic dicarboxylic acid, hydroxy
dicarboxylic acid and the like. Specifically, as the aromatic dicarboxylic
acid other than terephthalic acid, dicarboxylic acids including aromatic
group such as phthalic acid, isophthalic acid, 4,4' -diphenyl dicarboxylic
acid, diphenyl ether dicarboxylic acid, diphenyl sulfonic acid, diphenoxy
ethane dicarboxylic acid, 3,5-dicarboxy benzene sulfonate
(5-sulfoisophthalate), benzophenone dicarboxylic acid and the like can be
cited. As the aliphatic dicarboxylic acid, oxalic acid, succinic acid, adipic
acid, suberic acid, sebacic acid, dodecanedioic acid and the like can be cited.
As alicyclic dicarboxylic acid, cyclopropane dicarboxylic acid, cyclobutane
6
dicarboxylic acid, hexahydroterephthalic acid, cyclohexane dicarboxylic
acid, dimer dicarboxylic acid and the like can be cited. Here, dimer
dicarboxylic acid indicates a collective name of dicarboxylic acid obtained
by dimerizing unsaturated fatty acids such as oleic acid, linoleic acid,
a-linoleic acid, y-linoleic acid, arachidonic acid and the like or compounds
obtained by hydrogen reduction of unsaturated bond of remaining carbon:
carbon of dimerized dicarboxylic acid. When these dicarboxylic acids are
copolymerized, not limited to dicarboxylic acid but a form of dicarboxylic
diester compound obtained by subjecting I molecule of these dicarboxylic
acids to reaction with 2 molecules of alcohol having a hydrocarbon group
with I to 6 carbon atoms and the like may be used. Moreover, as
hydroxycarboxylic acid, glycolic acid, hydroxybutyric acid, hydroxyvaleric
acid, hydroxycaproic acid, hydroxypentanoic acid, hydroxyheptanoic acid,
hydroxyoctanoic acid and the like can be cited. Moreover, as alcoho 1
component other than the above-described alkylene glycol capable of
copolymerization, dihydroxy compounds such as diethylene glycol,
triethylene glyco 1, tetraethylene glyco 1, I, 2-propanedio 1, 1,3 -butaned io 1,
I ,4-hexanedio 1, 2-ethyl-1 ,6-hexanedio 1, 1,4-dihydroxycyclohexane,
I ,4-cyclohexanedimethano 1, 2, 2-(p- p- hydroxyethoxyphenyl)propane,
2,2-(p-p-hydroxyethoxyethoxyphenyl)propane, polyalkylene glycol and the
like can be cited. Other than the above, dihydroxy compound in which I to
8 molecules of ethylene oxide are added to phenolic hydroxyl group of
bisphenol A can be also used, and moreover, compound having three or
more ester-forming functional groups such as glycerin, pentaerythritol,
7
•
trimethylolpropane, trimesic acid, trimellitic acid and the like can be also
used within a range in which a copolymer is substantially linear.
[0010]
As polyalkylene terephthalate constituting the staple fibers of the
present invention, it is necessary to contain 10.0% or more of
biomass-derived carbon by radioactive carbon (carbon 14) measurement m
all the carbons in the polymer. Moreover, the upper limit of this numerical
value range is 100%, but at present, due to restriction in manufacturing, that
is, smce an industrial method usmg terephthalic acid made of
biomass-derived carbon for the terephthalic acid portion has not been
sufficiently established, 25.0% or less is preferable, 24.0% or less is more
preferable and 23.4% or less is still more preferable. If the technology
progresses in the future, this numerical value would exceed 25.0%, and
100% polyalkylene terephthalate could be manufactured. Here, in
specifying the content of a biomass-derived component in the present
invention, the meanmg of making radioactive carbon (carbon 14)
measurement will be described below.
[0011]
In the upper atmospheric layer, a reaction m which cosmiC rays
(neutron) collide with nitrogen atoms and generate carbon 14 atoms occurs
continuously, and since the generated carbon 14 atoms circulate the entire
atmosphere, it is indicated in measurement that carbon dioxide in the
atmosphere contains a certain ratio [107 pMC (percent modern carbon) as
an average value] of carbon 14. On the other hand, since the carbon 14
8
..
atoms contained under the ground is isolated from the above-described
circulation, only a reaction of returning to a nitrogen atom in a half-life of
5,370 years while releasing radiation occurs, and the carbon 14 atoms
scarcely remain in a fossil material such as current petroleum. Therefore,
by measuring concentration of carbon 14 in a sample as a target and by
calculating backward the content (107 pMC] of carbon 14 in the atmosphere
as an index, the ratio of the biomass-derived carbon in the carbon contained
in the sample can be acquired. As its specific measuring method, a method
using an accelerator mass spectrometer (AMS) is generally used as
discussed below.
[0012]
Moreover, in the measurement of radioactive carbon (carbon 14), the
content of a biomass-derived component can be also analyzed with respect
to recycled polyalkylene terephthalate obtained by material recycling,
chemical recycling and the like, and thus, this is an effective method also in
promoting cyclic use of the biomass-derived component for the purpose of
recycling. Therefore, as polyalkylene terephthalate of the present
invention, not only polyalkylene terephthalate newly obtained by
copolymerizing a biomass-derived component material but also
polyalkylene terephthalate obtained by material recycling or chemical
recycling using a biomass-derived polyalkylene terephthalate as a material
is included.
[0013]
9
As polyalkylene terephthalate of the present invention, as described
above, alkylene terephthalate is a major repeating unit, but if being formed
only of ethylene terephthalate, for example, the carbon atom constituting
the polymer has 8 atoms of terephthalic acid monomer and 2 atoms of
ethylene glycol monomer, and terephthalic acid and ethylene glycol react at
a molar ratio of 1: 1.
[0014]
Moreover, if a monomer component of another alkylene glycol IS
copolymerized, or if for example, 20 mol% of a diol component IS
biomass-derived 1,3-propanediol and the remaining diol component IS
biomass-derived ethylene glycol, the carbon ratio becomes terephthalic
acid: ethylene glycol: 1,3-propanediol = 8: 1.6:0.6, and the content of the
biomass-derived carbon is 21.6%. If the above composition is used as it is
as the diol component and oxalic acid having the smallest number of carbon
atoms as an acid component at 20 mol% is copolymerized, the carbon ratio
is terephthalic acid: oxalic acid: ethylene glycol: 1,3-propanediol =
6.4:0.8: 1.6:0.6, and the content of the biomass-derived carbon is 23.4%.
These cases are shown as an example for calculating the ratio of
biomass-derived carbon by radioactive carbon (carbon 14) measurement
described in claims and do not mean that the ratio of biomass-derived
carbon by the radioactive carbon (carbon 14) measurement in polyalkylene
terephthalate or polyalkylene naphthalate constituting staple fibers or a
wet-laid nonwoven fabric of the present invention is limited to these
numerical values.
10
• [0015]
Since the staple fibers obtained by using polyalkylene terephthalate
or polyalkylene naphthalate manufactured from a material containing the
biomass-derived carbon by the radioactive carbon (carbon 14) measurement
as above use a plant-derived material, an environmental burden can be
reduced as compared with manufacture of the same kind of polyester using a
conventional petroleum-derived material. That is, petroleum-derived
plastics are not degraded easily but accumulated in the environment if being
discarded in the environment. Moreover, a large quantity of carbon
dioxide is emitted when plastics are burned, which accelerates global
warmmg. In recent years, measures against serious environmental
problems such as a decrease in fossil fuels and an increase in carbon dioxide
in the atmosphere have become necessary. On the other hand, plants
absorb carbon dioxide in the air during growth and fixes carbon to
themselves by photosynthesis. Therefore, carbon dioxide generated when
plastic manufactured from the plants as a material is used and burned after
the use can be considered to be in the same quantity as that of the carbon
dioxide originally absorbed by the plants. That is, even burning of these
plastics merely leads to a so-called carbon neutral state and carbon dioxide
on the earth is not increased, thereby reducing the environmental burden.
[0016]
Polyalkylene naphthalate constituting the polyalkylene naphthalate
staple fibers of the present invention has alkylene glycol and naphthalene
dicarboxylic acid as main constituent components. The main constituent
11
• component means that a repeating unit of polyalkylene naphtha late is 80
mol% or more of the total. The polyalkylene naphthalate preferably
contains an ethylene naphthalate unit. The ethylene naphthalate preferably
contains an ethylene-2,6-naphthalate unit and the ethylene-2,6-naphthalate
unit is preferably contained in 90 mol% or more per repeating unit
constituting polyalkylene naphthalate, and the staple fibers may be formed
of a polyester polymer containing an appropriate third component at a ratio
less than the remaining 10 mol%. As alkylene glycol constituting
polyalkylene naphthalate other than the ethylene naphthalate unit, linear
alkylene glycol having 2 to 10 carbon atoms or preferably linear alkylene
glycol having 2 to 6 carbon atoms can be cited. Specifically, ethylene
glycol, trimethylene glycol, tetra methylene glycol, hexamethylene glycol,
octamethylene glycol or decamethylene glycol can be cited. As
naphthalene dicarboxylic acid, 2,6-naphthalenedicarboxylic acid,
2,7-naphthalenedicarboxylic acid, 1,5- naphthalenedicarboxylic acid or
1,6-naphthalenedicarboxylic acid can be cited. As the component other
than these alkylene glycol and naphthalenedicarboxylic acid, that is, as the
third component, a compound having two ester-forming functional groups
per molecule or as aliphatic dicarboxylic acid, for example, oxalic acid,
succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid
and the like can be cited. As alicyclic dicarboxylic acid, cyclopropane
dicarboxylic acid, cyclo butane dicarboxylic acid, hexahydroterephthalic
acid, cyclohexanedicarboxylic acid or dimer dicarboxylic acid can be cited.
More detailed description of the dimer dicarboxylic acids cited above are as
12
..
described above. As aromatic dicarboxylic acid other than
•
naphthalenedicarboxylic acid, phthalic acid, isophthalic acid, or
dicarboxylic acids including aromatic group such as 4,4' -diphenyl
dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfonic acid,
diphenoxy ethane dicarboxylic acid, 3,5-dicarboxy benzene sulfonate
(5-sulfoisophthalate), benzophenone dicarboxylic acid and the like can be
cited. When these dicarboxylic acids are copolymerized, not limited to
dicarboxylic acid but a form of dicarboxylic diester compound obtained by
subjecting 1 molecule of these dicarboxylic acids to reaction with 2
molecules of alcohol having a hydrocarbon group with 1 to 6 carbon atoms
may be used. Moreover, as hydroxycarboxylic acid, hydroxycarboxylic
acid containing an aliphatic group or an aromatic group such as glycolic
acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid,
hydroxypentanoic acid, hydroxyheptanoic acid, hydroxyoctanoic acid,
p-hydroxybenzoic acid, p-hydroxyethoxybenzoic acid and the like can be
cited. Moreover, as alcoholic component other than the above-described
alkylene glycol, dihydroxy compounds such as 1,2-propylene glycol,
diethylene glycol, neopentylene glycol, p-xylene glycol,
1,4-cyclohexanedimethanol, p,p' -bis(hydoxyethoxy)diphenyl sulfone,
1,4-bis(B-hydroxyethoxy)benzene,
2,2-bis(p-P-hydroxyethoxyphenyl)propane,
2,2-bis(p-p-hydroxyethoxyethoxyphenyl)propane, polyalkylene glycol and
the like can be cited. Other than the above, dihydroxy compound in which
1 to 8 molecules of ethylene oxide are added to phenolic hydroxyl group of
13
•
•
bisphenol A can be also used, and moreover, compound having three or
more ester-forming functional groups such as glycerin, pentaerythritol,
trimethylolpropane, trimesic acid, trimellitic acid and the like can be also
used within a range in which a copolymer is substantially linear.
[0017]
As polyalkylene naphthalate of the present invention, it is necessary
to contain 10.0% or more of biomass-derived carbon by radioactive carbon
(carbon 14) measurement in all the carbons in the polymer. Moreover, the
upper limit is preferably 25.0% or less, more preferably 24.0% or less and
still more preferably 23.4% or less. If the technology progresses in the
future, this numerical value would exceed 25.0%, and 100% polyalkylene
naphthalate could be manufactured.
[0018]
As polyalkylene naphthalate of the present invention, as described
above, alkylene naphthalate is a major repeating unit, but if being formed
only of ethylene terephthalate, the carbon atom constituting the polymer has
12 atoms of ethylene-2,6-naphthalate monomer and 2 atoms of ethylene
glycol monomer, and ethylene-2,6-naphthalate and ethylene glycol react at a
molar ratio of 1: 1.
[0019]
The above-described polyalkylene terephthalate and polyalkylene
naphthalate may contain additive agent, fluorescence brightening agent,
stabilizing agent, flame retardant, flame retardant auxiliary agent,
ultraviolet absorbing agent, antioxidant agent or various pigments for
14
•
coloring within a range in which the effects of the present invention are not
10 st.
[0020]
In the wet-laid nonwoven fabric of the present invention, the
polyalkylene terephthalate fully oriented staple fibers or polyalkylene
naphthalate fully oriented staple fibers are preferably fully oriented staple
fibers spun and drawn by an ordinary method by using polyalkylene
terephthalate or polyalkylene naphthalate. A draw ratio is preferably 1.2
to 30.0 times and more preferably 1.3 to 25.0 times. On the other hand, the
polyalkylene terephthalate low oriented staple fibers or polyalkylene
naphthalate low oriented staple fibers are those with fiber elongation degree
of 100 to 500% in the spun and fully oriented staple fibers by an ordinary
method using polyalkylene terephthalate or polyalkylene naphthalate.
Particularly 150 to 300% is preferable.
[0021 ]
On the other hand, the fully oriented staple fibers and low oriented
staple fibers are preferably staple fibers made of a single type of polyester
component, but also may be core-in-sheath type composite fibers in which a
polymer component (amorphous copolymer polyalkylene terephthalate, for
example) which is melted by heat treatment at 80 to 170°C applied after web
forming and exerts an adhesion effect is disposed in a sheath part and other
polymers (ordinary polyalkylene terephthalate such as polyethylene
terephthalate, polytrimethylene terephthalate, polybutylene terephthalate
and the like, for example) having a melting point higher than these
15
polymers by 20°C or more are disposed III a core part. The polyalkylene
terephthalate low oriented staple fibers and polyalkylene naphthalate low
oriented staple fibers may be known composite fibers such as concentric
core-and-sheath composite fibers, eccentric core-and-sheath composite
fibers, side-by-side composite fibers and the like, wherein a binder
component (low-melting-point component) forms the whole of or a part of
the surface of the single fiber.
[0022]
Here, the above-described amorphous copolymer polyalkylene
terephthalate preferably has 50 mol% or more of ethylene terephthalate unit
with respect to all the repeating units. Copolymer components other than
the ethylene terephthalate unit include dicarboxylic acid components such
as isophthalic acid, 2,6-naphthalenedicarboxylic acid,
2,7-naphthalenedicarboxylic acid, sodium 5-sulfoisophthalate, adipic acid,
sebacic acid, azelaic acid, dodecanedicarboxylic acid,
1,4-cyclohexanedicarboxylic acid and the like and diol components such as
1,2-propanediol, 1,3-propanedio 1, 1,4-butanedio 1, 1,5-pentanedio 1,
1,6-hexanediol, diethylene glycol, 1,4-cyclohexanediol,
1,4-cyclohexanedimethanol and the like. The copolymer polyalkylene
terephthalate is obtained as a random copolymer or a block copolymer
obtained from these materials. Particularly, terephthalic acid, isophthalic
acid, ethylene glycol and diethylene glycol which have been widely used are
preferably used as a main component in terms of costs. Such copolymer
polyalkylene terephthalate has a glass transition point within a range from
16
•
50 to 100°C and may not indicate clear crystalline melting point III some
cases.
[0023]
Here, it is important that the polyalkylene terephthalate staple fibers
and polyalkylene naphthalate staple fibers have single fiber fineness of
0.0001 to 7.0 decitex or preferably 0.001 to 5.0 decitex. More preferably
it can be selected from 0.01 to 3.0 decitex, 0.1 to 2.5 decitex or 0.5 to 2.0
e decitex. If the single fiber fineness is smaller than 0.0001 decitex, it is not
only that rigidity as a nonwoven fabric becomes small but also tensile
strength as fibers might deteriorate, and this is not favorable. On the
contrary, if the single fiber fineness is larger than 7.0 decitex, web
uniformity when being formed into a nonwoven fabric might deteriorate,
and this is not favorable. Moreover, in the polyalkylene terephthalate
staple fibers and polyalkylene naphthalate staple fibers of the present
invention, the cross-sectional shape of the single fiber is particularly
preferably circular, but modified cross-sectional shapes (hollow, polygon of
a triangle or more, flat, flat with a twist, multifoli and the like, for example)
may be used.
[0024]
In the polyalkylene terephthalate staple fibers and polyalkylene
naphthalate staple fibers of the present invention, the fiber lengths of the
both are preferably within a range of 0.1 to 20 mm. Preferably it can be
selected from 0.5 to 15 mm, more preferably from 1.0 to 12 mm, 2.0 to 10
mm or 3.0 to 8.0 mm. If the staple fiber length is smaller than 0.1 mm, the
17
•
aspect ratio becomes small, and it is likely that the staple fibers can easily
drop during a web forming process. Moreover, if the staple fiber length is
smaller than 0.1 mm, productivity of the staple fiber manufacturing process
needs to be lowered in order to cut a uniform fiber length in some cases.
On the contrary, if the staple fiber length is larger than 20 mm, it may
become difficult for the staple fibers to be distributed in a medium during
the web forming process. In the polyalkylene terephthalate staple fibers
and polyalkylene naphthalate staple fibers of the present invention,
crimping as described in Japanese Unexamined Patent Application
Publication No. 2001-268691 may be applied, but in order to increase water
dispersion performance and to have better web uniformity, these
polyalkylene terephthalate staple fibers preferably have no cnmp (no
crimping). Moreover, the polyalkylene terephthalate staple fibers and
polyalkylene naphthalate staple fibers of the present invention can be
suitably used for a wet-laid nonwoven fabric whether they are fully oriented
staple fibers or low oriented staple fibers, as will be described later.
[0025]
In the polyalkylene terephthalate staple fibers and polyalkylene
naphthalate staple fibers of the present invention, dry heat shrinkage at
180°C is preferably 0.5 to 15.0%. It is more preferably 1.0 to 10.0% and
still more preferably 2.0 to 8.0%. It can be set as appropriate depending
on the draw ratio during drawing processing or on the conditions of
relaxation heat treatment performed after that. On the other hand, in the
case of the polyalkylene terephthalate low oriented staple fibers and
18
•
polyalkylene naphthalate low oriented staple fibers, manufacturing is
possible so that the dry heat shrinkage at 180°C indicates a negative value
by selecting the relaxation heat treatment conditions and the like, but in the
case of the manufacturing under the conditions disclosed in the example,
fibers are broken due to melting under the temperature of 180°C and the dry
heat shrinkage at 180°C cannot be measured in some cases.
[0026]
Moreover, in order to fully exemplify the nature of the staple fibers
of the present invention, a wet-laid nonwoven fabric (a) which contains 15
mass% or more and 100 mass% or less of the polyalkylene terephthalate
staple fibers or polyalkylene naphthalate staple fibers for which the
biomass-derived carbon ratio, fineness, and fiber length are prescribed is
preferably employed. In this nonwoven fabric, anyone of 20 mass% or
more, 30 mass% or more or 40 mass% or more can be more preferably
selected. Subsequently, a wet-laid nonwoven fabric containing 15 mass%
or more of the polyalkylene terephthalate fully oriented staple fibers or
polyalkylene naphthalate fully oriented staple fibers can be preferably
employed. In this nonwoven fabric, anyone of 20 mass% or more, 30
mass% or more or 40 mass% or more can be more preferably selected.
Subsequently, a wet-laid nonwoven fabric containing 15 mass% or more of
the polyalkylene terephthalate low oriented staple fibers or polyalkylene
naphthalate low oriented staple fibers can be preferably employed. In this
nonwoven fabric, anyone of 20 mass% or more, 30 mass% or more or 40
mass% or more can be more preferably selected. By properly selecting a
19
mixing ratio of the fully oriented staple fibers and the low oriented staple
fibers, a nonwoven fabric with a good balance among tensile strength, tear
strength and web uniformity can be manufactured. More preferably, a
wet-laid nonwoven fabric W) composed of one type or two types or more of
only polyalkylene terephthalate staple fibers or one type or two types or
more of polyalkylene naphthalate staple fibers is employed. In this
wet-laid nonwoven fabric, too, 15 mass% or more and 100 mass% or less of
• the polyalkylene terephthalate low oriented staple fibers or polyalkylene
naphthalate low oriented staple fibers are preferably contained. Therefore,
the former wet-laid nonwoven fabric (u) is likely to become a nonwoven
fabric containing polyolefin fibers, pulps and the like, for example, while
the latter wet-laid nonwoven fabric (B) becomes a nonwoven fabric made of
100% polyalkylene terephthalate staple fibers and/or polyalkylene
naphthalate staple fibers.
[0027]
• In the nonwoven fabric of the present invention, regarding the
weight ratio A/B between the polyalkylene terephthalate fully oriented
staple fibers and the polyalkylene terephthalate low oriented staple fibers or
between the polyalkylene naphthalate fully oriented staple fibers and the
polyalkylene naphthalate low oriented staple fibers, a wet-laid nonwoven
fabric having a weight ratio within a range from 15/85 to 85/15, preferably
from 20/80 to 80/20 or from 30/70 to 70/30 or more preferably from 40/60
to 60/40 is preferable. If the weight ratio of the low oriented staple fibers
is smaller than the stated range, form stability of the nonwoven fabric is lost
20
•
• and scuffing or the like may easily occur, which is not preferable. On the
contrary, if the weight ratio of the low oriented staple fibers is larger than
the stated range, the completed wet-laid nonwoven fabric is too compact
and resembles a film, and tensile strength or tear strength as a wet-laid
nonwoven fabric deteriorates, which is not preferable.
[0028]
In the wet-laid nonwoven fabric composed only of the polyalkylene
• terephthalate fully oriented staple fibers and the polyalkylene terephthalate
low oriented staple fibers or only of the polyalkylene naphthalate fully
oriented staple fibers and the polyalkylene naphthalate low oriented staple
fibers, aromatic polyester fibers (for example polycyclohexane
terephthalate fibers, and poly(cyclohexane dimethylene)terephthalate
fibers), wooden pulp (pulp mainly using softwood, also referred to as NBKP
in some cases), rayon fiber or the like may be contained if it is 10 mass% or
less, preferably 5 mass% or less or more preferably 0.1 to 4.0 mass% to the
total weight of the nonwoven fabric. Moreover, the weight per unit area of
the wet-laid nonwoven fabric in the present invention may be selected in
accordance with the purpose and is not particularly limited but it is usually
within a range of 10 to 500 g/m2
, preferably 20 to 300 g/m2 or more, more
preferably 30 to 200 g/m2
, further more preferably 50 to 100 g/m2
.
[0029]
The staple fibers of the present invention described above can be
manufactured by the following method, for example. Polyalkylene
terephthalate or polyalkylene naphthalate to which drying treatment is
21
•
sufficiently applied is discharged from a spinneret using a known spinning
facility and taken up at a speed of 100 to 2000 m/min while being cooled so
as to obtain an low oriented yarn. Subsequently, drawing treatment is
applied to the obtained low oriented yarns in hot water at 70 to lOO°C or in
a steam at 100 to 125°C. If it is used as a binder fiber for a nonwoven
fabric as will be described later, the above-described drawing treatment
does not have to be applied in some cases. Moreover, after the drawing
treatment or in an undrawn state, crimping is applied as necessary, an oil
agent according to the application and purpose is applied and drying and
relaxation thermal treatment are performed and then, it is cut to a
predetermined fiber length so that the staple fibers of the present invention
can be obtained.
[0030]
The oil agent used in the manufacture of the staple fibers may
contain silicone compounds of an amount not obstructing achievement of
the object of the present invention and a type not obstructing achievement
of the object of the present invention. Since the staple fibers are dispersed
in water during manufacturing of the wet-laid nonwoven fabric, use of a
copolymer of polyalkylene terephthalate and polyethylene glycol having
hydrophilic property and a good affinity with polyalkylene terephthalate or
polyalkylene naphthalate can be preferably employed as an oil agent. This
copolymer IS also referred to as polyether/ester copolymer. In this
copolymer, III order to have a good balance between hydrophilic property
and affinity with polyester, a polyether/ester copolymer satisfying at least
22
•
•
any of the fo llowing conditions is preferably used. A number average
molecular weight of polyethylene glycol to be used is preferably 1000 to
5000, or more preferably 1500 to 4000. Polyethylene glycol preferably in
50 to 80 mass%, or more preferably 60 to 75 mass% is used with respect to
the total weight of the polyether/ester copolymer. This polyethylene
glycol constitutes a polyether portion. The remaining portion of 20 to 50
mass% or preferably 25 to 40 mass% constitutes a polyester portion. The
dicarboxylic acid component constituting the polyester portion is preferably
copolymerized at 5 to 30 mol% of isophthalic acid with respect to the total
dicarboxylic acid component constituting the polyester portion. As the
remaining dicarboxylic acid component, terephthalic acid is preferably used.
As the diol component constituting the polyester portion, ethylene glycol is
preferably used. This oil agent is preferably allowed to adhere at 0.0005
to 0.01 mass% with respect to the staple fibers. The amount of the oil
agent to be adhered to the staple fibers is preferably within a range from
0.0008 to 0.008 mass%, more preferably from 0.001 to 0.005 mass% or most
preferably from 0.002 to 0.004 mass%.
[0031 ]
Next, a manufacturing method of a wet-laid nonwoven fabric of the
present invention will be described. The staple fibers obtained by the
above-described operations, that is, the polyalkylene terephthalate fully
oriented staple fibers and the polyalkylene terephthalate low oriented staple
fibers or the polyalkylene naphthalate fully oriented staple fibers and the
polyalkylene naphthalate low oriented staple fibers are subjected to
23
• wet-laid web forming and then dried. At this time, drying is performed
after the wet-laid web forming by using the fully oriented staple fibers (A)
and the low oriented staple fibers (B) so that their weight ratio AlB is
preferably within the range of 15/85 to 85/15. At that time, as the wet-laid
web forming method, short wire, long wire, cylinder and their combination
(multilayer web forming) can be used depending on the shape of a wire part
for web forming and the like, and any method can complete wet-laid web
• forming without a problem. As the drying treatment process, a drum dryer
or an air-through dryer is preferably used for applying heat treatment and
drying. In more detail, Yankee dryer for bringing fibers in contact with a
cylindrical drum, multi-cylinder drum in which a large number of drums are
aligned, hot air suction (air-through dryer) by hot air and the like can be
used. At that time, a range of 80 to 150°C is preferable as a drying
treatment temperature.
•
[0032]
After the drying treatment process, calendering (nonwoven fabric is
passed through two heating rolls) treatment can be performed in the final
stage as necessary. By applying such calendering treatment, at least a part
of the low oriented staple fibers is melted and heat adhesion between the
staple fibers become firm, and a wet-laid nonwoven fabric having excellent
tensile strength can be obtained. In order to improve tensile strength of a
nonwoven fabric as above, application of calendering becomes important in
some cases. Here, with a calendering machine, a known material (metal,
paper, resin and the like) and a known roll (flat, emboss and the like) can be
24
•
•
used for calendering. At that time, a surface temperature of the calender
roll is preferably within a range of 100 to 200°C and a line pressure IS
preferably within a range of 100 to 300 kgf/cm (980 to 2940 N/cm).
[0033]
In the present invention, manufacturing of a wet-laid nonwoven
fabric by the following manufacturing method is also possible. That is, a
wet-laid nonwoven fabric composed of only the polyalkylene terephthalate
low oriented staple fibers, only the polyalkylene terephthalate fully oriented
staple fibers, or only the polyalkylene terephthalate fully oriented staple
fibers and low oriented staple fibers or a wet-laid nonwoven fabric web
composed of only the polyalkylene naphthalate low oriented staple fibers,
only the polyalkylene naphthalate fully oriented staple fibers or only the
polyalkylene naphthalate fully oriented staple fibers and the polyalkylenc
naphthalate low oriented staple fibers IS made once by using a known
wet-laid web forming method. Then, if low oriented staple fibers are
contained in the staple fibers constituting the wet-laid nonwoven fabric web,
the low oriented staple fibers are melted so as to bond the staple fibers
together and to make a sheet. Moreover, the sheet is laminated in a single
layer or two layers or more, or if low oriented staple fibers are not
contained in the wet-laid nonwoven web, the wet-laid nonwoven web is
laminated in a single layer or two layers or more and the staple fibers are
three dimensionally entangled by a high-pressure water jet so that a wet-laid
nonwoven fabric can be made. At that time, a nozzle hole diameter for
injecting the water flow to the sheet or the wet-laid nonwoven fabric web is
25
•
•
preferably within a range of 10 to 500 11m and a nozzle hole interval is
preferably from 500 11m to 10 mm in order to entangle them firmly and keep
web uniformity favorable. Moreover, the water pressure is preferably used
within a range of 10 to 250 kg/cm2
. A machining speed is preferably used
within a range of 15 to 200 m/min.
[0034]
The wet-laid nonwoven fabric obtained by the present invention is
excellent In adhesive strength and heat resistance at a reduced
environmental burden by USIng the polyalkylene terephthalate or
polyalkylene naphthalate staple fibers containing biomass-derived carbon.
Example
[0035]
Subsequently, examples and comparative examples of the present
invention will be described in detail, but the contents of the present
invention are not limited by them. Each measurement item in examples
was measured by the following methods.
[0036]
(a) Glass transition temperature (Tg)
Measured under the condition of a temperature flSIng speed of
20°C/min In accordance with differential scanning calorimetry (DSC)
described In JIS (representing Japanese Industrial Standard. The same
applies to the following) K7121.
[0037]
(b) Intrinsic viscosity (YJ)
26
• Determined from a value obtained by measuring the viscosity of a
diluted solution III which a polyester sample IS dissolved III
orthochloropheno 1 at 100°C for 60 minutes by using Ubbelohde viscometer
at 35°C.
[0038]
(c) Single fiber fineness
Measured in accordance with the method described III lIS L
1015:2005 8.5.1A method.
[0039]
(d) Fiber length
Measured in accordance with the method described III lIS L
1015:2005 8.4.1C method.
[0040]
(e) Fiber strength, fiber elongation
Measured in accordance with the method described III lIS L
1015:2005 8.7.1.
[0041 ]
(f) Crimping number, crimping rate
Measured in accordance with the method described III lIS L
1015:2005 8.12.
[0042]
(g) Dry heat shrinkage at 180°C.
Measured at 180°C in accordance with the method described in lIS
LI015:20058.15b.
27
•
•
[0043 ]
(h) Thickness, weight per unit area (weight, mass per unit area) and
density
The thickness of the nonwoven fabric was measured in accordance
with the method described in JIS L19l3:20l0 6.1 and the weight per unit
area of the nonwoven fabric was measured by the method described in JIS
L19l3 :20 10 6. 2. Moreover, the density of the nonwoven fabric was
calculated by dividing the weight per unit area of the nonwoven fabric by
the above-described value of the nonwoven fabric thickness.
[0044]
(i) Wet-laid nonwoven fabric tensile strength
Measured based on JIS P8ll3 (Paper and board -- Determination of
tensile properties).
[0045]
(j) Content of radioactive carbon (carbon 14) (biomass-derived
carbon ratio)
A mixed ratio sample of the biomass-derived carbon by
measurement of radioactive carbon (carbon 14) was subjected to an
accelerator mass spectrometer (AMS) and the content of carbon 14 was
measured. Carbon dioxide in the atmosphere contains a certain ratio of
carbon 14 (because neutrons collide with nitrogen atoms and generate
carbon 14 atoms in the upper atmospheric layer), but fossil materials such
as petroleum contain almost no carbon 14 (because carbon 14 changes to
nitrogen under the ground in a half-life of 5370 years while releasing
28
•
•
radiation). On the other hand, the ratio of carbon 14 in the atmosphere at
present is measured to be a specific value [107 pMC (percent modern
carbon) as an average value], and it is known that carbon 14 is taken in at
this ratio into the present plants performing photosynthesis. Therefore, by
measuring the contents of all the carbons and the carbon 14 in the sample,
the ratio of the biomass-derived carbon in the carbon contained in the
sample can be determined (See the following formula):
Biomass-derived carbon ratio (%) = (amount of biomass-derived
carbon in sample/total carbon amount in sample) x 100
[0046]
(k) Web uniformity
The state of the surface of a finished nonwoven fabric sample was
visually checked and 4-grade evaluation was made. Evaluation was
designated as 4th-grade, 3rd-grade, 2nd-grade, and 1st-grade in the order of
descending quality from the best web uniformity.
[0047]
In the following Examples/Comparative Examples, polyethylene
terephthalate containing 10% or more and 100% or less of biomass-derived
carbon is referred to as bio-polyethylene terephthalate or bio-PET, and
polyethylene naphthalate containing 10% or more and 100% or less of
biomass-derived carbon is referred to as bio-polyethylene naphthalate or
bio-PEN. Moreover, known polyethylene terephthalate not containing
biomass-derived carbon is referred to as petroleum-derived polyethylene
terephthalate or petroleum-derived PET, and known polyethylene
29
•
•
naphtha late not containing biomass-derived carbon is referred to as
petroleum-derived polyethylene naphthalate or petroleum-derived PEN.
[0048] [Example 1]
(Bio-polyethylene terephthalate fully oriented staple fibers)
After bio-polyethylene terephthalate chips manufactured by Teijin
were dried, it was melted at 290°C and discharged at 180 g/min through a
spinneret having 1192 holes and taken in at a speed of 500 m/min so as to
obtain low oriented fibers. The low oriented fibers were made to converge
into a tow of approximately 140 thousand decitex and then drawn in hot
water to 17.7 times so as to obtain fully oriented fibers. Moreover, the
fully oriented fibers were made to pass through aqueous emulsion (solid
concentration at 3.0%) of a polyether/polyester copolymer having number
average molecular weight of approximately 10000 shown b~low and
squeezed so that moisture content in the fully oriented fibers falls to
approximately 12%. In this polyether/polyester copolymer, a polyester
portion is composed of 80 mol% of terephthalic acid and 20 mol% of
isophthalic acid as the dicarboxylic acid component and ethylene glycol as
the diol component of the polyester portion. The polyester portion at 30
mass% of the polyether/ester copolymer is composed of this polyethylene
terephthalate/isophthalate copolymer, while the remaining 70 mass% of the
polyether portion is a copolymer composed of 70 mass% of polyethylene
glyco I having number average molecular weight of 3000. After that, the
fully oriented fibers were cut at a fiber length of 5 mm without drying,
30
•
•
drying was applied, and bio-polyethylene terephthalate fully oriented staple
fibers (no crimp) having single fiber fineness of 0.60 decitex were obtained.
[0049] (Bio-polyethylene terephthalate low oriented staple fibers)
After bio-polyethylene terephthalate chips manufactured by Teijin
were dried, it was melted at 290°C and discharged at 180 g/min through a
spinneret having 1192 holes and taken in at a speed of 500 m/min so as to
obtain low oriented fibers. The low oriented fibers were made to converge
into a tow of approximately 140 thousand decitex. After that, without
drawing, the low oriented fibers were made to pass through aqueous
emulsion (solid concentration at 3.0%) of a polyether/polyester copolymer
having number average molecular weight of approximately 10000 shown
below, and squeezed so that moisture content in the fully oriented fibers
falls to approximately 12%. The composition of the polyether/polyester
copolymer is the same as that of the bio-polyethylene terephthalate fully
oriented staple fibers. After that, the low oriented fibers were cut at a
fiber length of 5 mm without drying, drying was applied, and
bio-polyethylene terephthalate low oriented staple fibers (no crimp) having
single fiber fineness of 1.2 decitex were obtained.
[0050] (Wet-laid web forming processing, drying treatment and calendering
treatment)
The bio-polyethylene terephthalate fully oriented staple fibers and
the bio-polyethylene terephthalate low oriented staple fibers were mixed
and agitated at the weight ratio of 70/30 using water as a medium and then
made into paper using a manual paper machine (by Kumagai Riki Kogyo Co.,
31
• Ltd., model: No. 2555, standard square sheet machine, the same applies to
the following). Subsequently, the papered fibers were subjected to drying
treatment at 120°C for 2 minutes by using a rotary dryer (by Kumagai Riki
Kogyo Co., Ltd., model: 2575-II, rotary dryer (high temperature type)).
After that, calendering (180°C x 200 kg/cm (1960 N/cm)) was applied by
using a device composed of metal roll/metal roll, and a wet-laid nonwoven
fabric was obtained. The physical characteristics of the fully oriented
staple fibers, the low oriented staple fibers and the wet-laid nonwoven
fabric are shown in Table 1.
[0051] [Example 2]
A wet-laid nonwoven fabric was obtained by the method similar to
that of Example 1 except that the mixing ratio between the fully oriented
staple fibers and the low oriented staple fibers was changed from that given
in Example 1. The physical characteristics of the fully oriented staple
fibers, the low oriented staple fibers and the wet-laid nonwoven fabric are
shown in Table 1.
[0052] [Example 3]
(Bio-polyethylene naphthalate fully oriented staple fibers)
After bio-polyethylene naphthalate chips manufactured by Teijin
were dried, it was melted at 320°C and discharged at 310 g/min through a
spinneret having 1305 holes and taken in at a speed of 1350 m/min so as to
obtain low oriented fibers. The low oriented fibers were made to converge
into a tow of approximately 130 thousand decitex and then drawn in hot
water to 1.85 times so as to obtain fully oriented fibers. Moreover, the
32
fully oriented fibers were made to pass through the same aqueous emulsion
(solid concentration at 3.0%) of a polyether/polyester copolymer as that
used in Example 1 and squeezed so that moisture content in the fully
oriented fibers falls to approximately 12%. After that, the fully oriented
fibers were cut at a fiber length of 5 mm without drying, drying was applied,
and bio-polyethylene naphthalate fully oriented staple fibers (no crimp)
having single fiber fineness of 0.5 decitex were obtained.
[0053] (Bio-polyethylene naphthalate low oriented staple fibers)
After bio-polyethylene naphthalate chips manufactured by Teijin
were dried, it was melted at 320°C and discharged at 290 g/min through a
spinneret having 1305 holes and taken in at a speed of 1000 m/min so as to
obtain low oriented fibers. The low oriented fibers were made to converge
into a tow of approximately 140 thousand decitex. After that, without
drawing, the low oriented fibers were made to pass through the same
aqueous emulsion (solid concentration at 3.0%) of a polyether/polyester
copolymer as that used in Example 1 and squeezed so that moisture content
in the low oriented fibers falls to approximately 12%. After that, the low
oriented fibers were cut at a fiber length of 5 mm without drying, drying
was applied, and bio-polyethylene naphthalate low oriented staple fibers
(no crimp) having single fiber fineness of 1.1 decitex were obtained.
[0054] (Wet-laid web forming processing, drying treatment and calendering
treatment)
The bio-polyethylene naphthalate fully oriented staple fibers and the
bio-polyethylene naphthalate low oriented staple fibers were mixed and
33
agitated at the weight ratio of 70/30 using water as a medium and then made
into paper using a manual papering machine (by Kumagai Riki Kogyo Co.,
Ltd., model: No. 2555, standard square sheet machine, the same applies to
the following). Subsequently, the papered fibers were subjected to drying
treatment at 145°C for 2 minutes by using a rotary dryer (by Kumagai Riki
Kogyo Co., Ltd., model: 2575-II, rotary dryer (high temperature type)).
After that, calendering (180°C x 200 kg/cm (1960 N/cm)) was applied by
using metal roll/metal roll, and a wet-laid nonwoven fabric was obtained.
The physical characteristics of the fully oriented staple fibers, the low
oriented staple fibers and the wet-laid nonwoven fabric are shown in Table
1.
[0055] [Example 4]
A wet-laid nonwoven fabric was obtained by the method similar to
that of Example 3 except that the ratio between the fully oriented staple
fibers and the low oriented staple fibers was changed from that given in
Example 3. The physical characteristics of the fully oriented staple fibers,
the low oriented staple fibers and the wet-laid nonwoven fabric are shown
in Table 1.
34
[0056][Table I]
Item Unit Example I Example 2 Example 3 Example 4
Polymer type - Bio-PET Bio-PET Bio-PEN Bio-PEN
Single fiber finenes s dtex 0.6 0.6 0.5 0.5
Fully Fiber length mm 5.0 5.0 5.0 5.0
oriented Fiber strength cN/dtex 4.5 4.5 4.5 4.5
fiber Fiber elongation % 50 50 35.8 35.8
Dry heat shrinkage at 180'1::: % 5.0 5.0 5.5 5.5
Biomass-derived carbon ratio % 20 20 10 10
Polymer type Bio-PET Bio-PET Bio-PEN Bio-PEN
Binder fibers (type) UDY UDY UDY UDY
Single fiber fineness dtex 1.2 1.2 l.l l.l
Low Fiber length mm 5.0 5.0 5.0 5.0
oriented
Fiber strength cN/dtex 0.91 0.91 1.94 1.94
fiber
(binder
Fiber elongation % 136.7 136.7 152.6 152.6
fibers) Measurement Measurement Measurement Measurement
Dry heat shrinkage at 180'1::: % impossible due to impossible due to impossible due to impossible due to
fusing fusing fusing fusing
Ratio ofbiomass-derived carbon content % 20 20 10 10
Example I Example 2 Example 3 Example 4
Other fibers - - - - -
Raw cotton composition
mass°,io 70/30/0 50/50/0 70/30/0 50/50/0
(fully oriented fiberllow oriented fiber/others)
Manufacturing method
Wet-laid web Wet-laid web Wet-laid web Wet-laid web -
fonning method fonning method fonning method fonning method
Rotary dryer treatment conditions - 120'C'2min 120'C'2min 145'Cv2min 145'Cx2min
Air-through dry er treatment conditions - - - -
Wet-laid Calendering treatment conditions
180'C'200kg/cm 180'C '200kglcm 18(1' Cx200kglcm 180'C'200kglcm
(metal roll/metal mil)
-
nonwoven
fabric Weight per unit area glm2 70 71 69 70
Thickness mm 0.11 0.10 0.08 0.09
Density glcm' 0.64 0.71 0.86 0.78
Tensile strength N/15mm 21 32 32 41
Web unifonnity class 4 4 4 4
Ratio ofbiomass-derived carbon content % 20 20 10 10
Productivity of Productivity of Productivity of Productivity of
manufacturing manufacturing manufacturing manufacturing
process was process was process was process was
favorable, web favorable, web favorable, web favorable, web
unifonnity was unifonnity was unifonnity was unifonnity was
Results excellent and excellent and excellent and excellent and
nonwoven fabrics nonwoven fabrics nonwoven fabrics nonwoven fabrics
with reduced with reduced with reduced with reduced
enviromnental enviromnental environmental enviromnental
burden were burden were burden were burden were
obtained. obtained. obtained. obtained.
UDY:Undrawing Yam
[0057] [Example 5]
The fully oriented staple fibers described in Example I, low oriented
composite staple fibers shown below, and wooden pulp (NBKP) were mixed
35
and agitated at the mass% ratio of 50/30/20 usmg water as a medium.
Using the mixture, a wet-laid nonwoven fabric was obtained by the method
similar to that of Example 1 except that calendering was not performed.
The physical characteristics of the fully oriented staple fibers, the low
oriented composite staple fibers, and the wet-laid nonwoven fabric are
shown in Table 2.
[0058] (Manufacturing of low oriented composite staple fibers)
A pellet of amorphous copolymer polyethylene terephthalate
obtained by copolymerizing at a fraction of 40 mol% of isophthalic acid
having intrinsic viscosity [11] of 0.55 dL/g and Tg of 65°C measured after
vacuum drying at 50°C for 24 hours was melted in a biaxial extruder, and
melted polyester at 250°C was obtained. On the other hand, a pellet of
polyethylene terephthalate having intrinsic "iscosity [11] of 0.61 dL/g
measured after vacuum drying at 120°C for 16 hours was melted in a biaxial
extruder, and melted polyester at 280°C was obtained. The two types of
melted polyester, the former of which was used as a sheath component A
and the latter as a core component B, were melted and discharged in a
composite manner through a known core-and-sheath composite spinneret
having 1032 pieces of circular-hole capillaries, each having a diameter of
0.3 mm so that the cross-sectional area ratio becomes A:B = 50:50. At this
time, the composite spinneret temperature was 285°C and the discharged
amount was 870 g/min. Moreover, the melted and discharged polyester
was cooled by cooling air at 30°C and reeled at 1150 m/min so as to obtain
an low oriented yarn. Subsequently, it was cut at a fiber length of 5.0 mm
36
•
so as to obtain low oriented composite staple fibers having single fiber
fineness of 1.1 decitex.
[0059] [Example 6]
A wet-laid nonwoven fabric was obtained by the method similar to
that of Example 5 except that the ratio between the fully oriented staple
fibers, the low oriented composite staple fibers, and NBKP was changed
from that given in Example 5. The physical characteristics of the fully
oriented staple fibers, the low oriented composite staple fibers, and the
wet-laid nonwoven fabric are shown in Table 2.
[0060] [Example 7]
The manufacturing conditions of the fully oriented staple fibers
described in Example 1 were changed, and fully oriented staple fibers
having single fiber fineness of 0.17 decitex were obtained. A web was
manufactured by an ordinary wet-laid spun lace method using only the fully
oriented staple fibers, drying at 130DC for 2 minutes was applied by an
air-through dryer, and a wet-laid nonwoven fabric was obtained. In the
spun lace method, 3 pieces of nozzle head were used, and the staple fibers
in the web were three dimensionally entangled by using a columnar water
jet. The conditions of the three-head nozzle composed of first to third
head are as follows:
A) First head:
Water flow direction: downward direction
Nozzle alignment form: 2-row zigzagged alignment
Nozzle hole diameter: 120 Ilm
37
Nozzle hole interval: 1 mm
Nozzle row interval: 1 mm
Water flow pressure: 50 kg/cm2
B) Second head:
Water flow direction: upward direction
Nozzle alignment form: 2-row zigzagged alignment
Nozzle hole diameter: 120 Ilm
Nozzle hole interval: 1 mm
Nozzle row interval: 1 mm
Water flow pressure: 100 kg/cm2
C) Third head:
Water flow direction: from downward direction
Nozzle alignment form: 2-row zigzagged alignment
Nozzle hole diameter: 80 Ilm
Nozzle hole interval: 1 mm
Nozzle row interval: 1 mm
Water flow pressure: 100 kg/cm2
The physical characteristics of those fully oriented staple fibers and
the wet-laid nonwoven fabric are shown in Table 2.
[0061] [Example 8]
A wet-laid nonwoven fabric was obtained by the method similar to
that of Example 7 except that the composition ratio of raw cotton in the
description of Example 7 was changed from 100 mass% bio-polyethylene
terephthalate having single fiber fineness of 0.17 decitex to 50 mass%
38
bio-polyethylene terephthalate having single fiber fineness of 0.17 decitex,
lO mass% low oriented composite staple fibers used in Example 5, and 40
mass% rayon staple fibers having single fiber fineness of 0.7 decitex and
fiber length of 8 mm. The physical characteristics of the fully oriented
staple fibers, the low oriented composite staple fibers, and the wet-laid
nonwoven fabric are shown in Table 2.
39
,
[0062] [Table2]
Item Unit Example 5 Example 6 Example 7 Example 8
Polymer type - Bio-PET Bio-PET Bio-PET Bio-PET
Single fiber fineness dtex 0.6 0.6 0.17 0.17
Fully Fiber length mm 5.0 5.0 5.0 5.0
oriented Fiber strength cN/dtex 4.5 4.5 2.51 2.51
fiber Fiber elongation % 50 50 31.9 31.9
Dry heat shrinkage at 180"(; % 5.0 5.0 3.2 3.2
Ratio ofbiomass-: 0.6 06 1.63 0.17
Fiber length mm 5.0 5.0 5.0 5.0
Fully
Fiber strength eN/dte>: 4.5 4.5 3.36 2.51
oriented
fiber
Fiber elongation % 50 50 47,4 31.9
Measurement
Dry heat shrinkage at 180"C % 5.0 5.0 impossible due to 3.2
fusing
Ratio of biomass-derived carbon content % 20 0 100 0
Polymer type Bio-PET
Petroleum-derived
- Poly lactic acid None PET
Binder fibers (ty pel UDY UDY UDY -
Low Single fiber fineness dte>: 1.2 1.2 1.5
oriented. Fiuer length mm 5.0 50 5.0
fiber Fiber strength eN/dte>: 0.91 0.91 1.17
(binder Fiber elongation % 136.7 136.7 126
fibers)
Measurement Measurement Measurement
Dry heat shrinkage at 180"C % impossible due to impossible due to impossible due to -
fusing fusing fusing
/ Ratio of biomass-derived carbon content % 20 0 100
Comparative Comparative Comparative Comparative
Example I Example 2 Example 3 Example 4
Other fibers - -
Raw cotton composition
mass% 90/1010 70/3010 6014010 100/010
(fully oriented fiberllow oriented fiber/others)
Manufaeturing method
- Wet-laid web Wet-laid web Wet-laid web Wet-laid spun lace forming method forming method forming method method
Rotary dryer treatment conditions - 120"Cx2min 120