U.S. patent application number 10/358331 was filed with the patent office on 2003-09-18 for nonwoven fabric for wiper.
This patent application is currently assigned to KURARAY CO. LTD.. Invention is credited to Kiyooka, Sumito, Moriyasu, Hidetoshi, Yokomizo, Masako.
Application Number | 20030176132 10/358331 |
Document ID | / |
Family ID | 27654801 |
Filed Date | 2003-09-18 |
United States Patent
Application |
20030176132 |
Kind Code |
A1 |
Moriyasu, Hidetoshi ; et
al. |
September 18, 2003 |
Nonwoven fabric for wiper
Abstract
A nonwoven fabric contains extra-fine fibers which contain
linear bonded regions and/or dot-like bonded regions, and
non-bonded regions on a surface of the extra-fine fibers. The
bonded regions account for from 10 to 80% of a surface area of the
nonwoven fabric. A distance between neighboring bonded regions is
at most 20 mm. The nonwoven fabric has an excellent ability to wipe
off dirt including oily stains and persistent stains, it well
follows even three-dimensionally patterned faces of the articles to
be wiped with it. Its feel and its washing resistance are good.
Inventors: |
Moriyasu, Hidetoshi;
(Okayama-City, JP) ; Yokomizo, Masako;
(Okayama-City, JP) ; Kiyooka, Sumito;
(Okayama-City, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
KURARAY CO. LTD.
Kurashiki-City
JP
|
Family ID: |
27654801 |
Appl. No.: |
10/358331 |
Filed: |
February 5, 2003 |
Current U.S.
Class: |
442/361 ;
442/327; 442/334 |
Current CPC
Class: |
Y10T 442/608 20150401;
Y10T 442/637 20150401; B08B 1/006 20130101; D04H 1/62 20130101;
D04H 1/4282 20130101; D04H 1/54 20130101; D04H 1/48 20130101; D04H
1/49 20130101; D04H 1/43835 20200501; D04H 1/4326 20130101; D04H
1/43832 20200501; D04H 1/43838 20200501; D04H 1/43828 20200501;
D04H 1/732 20130101; Y10T 442/60 20150401; D04H 1/495 20130101;
A47L 13/16 20130101; D04H 1/66 20130101 |
Class at
Publication: |
442/361 ;
442/327; 442/334 |
International
Class: |
D04H 001/00; D04H
003/00; D04H 005/00; D04H 013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 8, 2002 |
JP |
2002-031914 |
Claims
1. A nonwoven fabric, comprising: extra-fine fibers comprising:
bonded regions in a form selected from the group consisting of
linear bonded regions, dot-like bonded regions and mixtures
thereof, and non-bonded regions on a surface of said extra-fine
fibers; wherein said bonded regions account for from 10 to 80% of a
surface area of said nonwoven fabric; and wherein a distance
between neighboring bonded regions is at most 20 mm.
2. The nonwoven fabric according to claim 1, wherein said surface
has an embossed pattern; wherein a height difference between the
hills and the valleys of said embossed pattern is at least 20% of
the thickness of the nonwoven fabric.
3. The nonwoven fabric according to claim 1 which comprises 100% of
extra-fine fibers.
4. A wiper made of the nonwoven fabric according to claim 1.
5. The nonwoven fabric according to claim 1, wherein a single fiber
fineness of said extra-fine fibers is not more than 0.5 dtex.
6. The nonwoven fabric according to claim 1, wherein said
extra-fine fibers are splittable conjugated fibers.
7. The nonwoven fabric according to claim 6, wherein said
splittable conjugated fibers comprise at least two different types
of resin.
8. The nonwoven fabric according to claim 7, wherein said resin is
selected from the group consisting of polyester polymers,
polyolefin polymers, polyamide polymers, polystyrene polymers,
polyacrylonitrile polymers, polyvinyl alcohol polymers,
ethylene-vinyl alcohol copolymers and mixtures thereof.
9. The nonwoven fabric according to claim 6, wherein said
splittable conjugated fibers comprise two different types of resin
components which are conjugated in the following manner: 1) into
bicomponent fibers having a chrysanthemum-patterned cross-sectional
profile in which the two resin components are alternately radially
aligned; 2) into bicomponent fibers having a bimetal-patterned
cross-sectional profile in which the two resin components are
alternately layered; or 3) into bicomponent fibers having a
sea/island patterned cross-sectional profile in which islands of
one resin component are dispersed in a sea matrix of the other
resin component.
10. The nonwoven fabric for wipers according to claim 1, comprising
heat-fusing fibers.
11. The nonwoven fabric for wipers according to claim 10, wherein a
melting point difference between said extra-fine fibers and said
heat-fusing fibers is at least 10.degree. C.
12. The nonwoven fabric for wipers according to claim 10, wherein
said heat-fusing fibers comprise 6-nylon/polyethylene copolymer,
polypropylene/polyethylene copolymer, polypropylene/ethylene-vinyl
acetate copolymer, polyester/polypropylene copolymer,
polyester/polyethylene copolymer, 6-nylon/66-nylon copolymer and
high-density polyester/low-density polyester copolymer.
13. The nonwoven fabric for wipers according to claim 1, wherein
said bonded regions of the nonwoven fabric are formed by using a
resin binder.
14. The nonwoven fabric for wipers according to claim 1, wherein at
least a part of said extrta-fine fibers in said non-bonded regions
embedded in said bonded regions.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a nonwoven fabric for a
wiper, especially a wiper that has the ability to wipe off oily
stains and caked persistent stains, and which exhibits little
fluffing even when used repeatedly, and has good washing
resistance.
[0003] 2. Discussion of the Background
[0004] Various nonwoven fabric wipers of extra-fine fibers have
been proposed and are now widely used. For example, a wiping
material has been proposed, which is produced by hydroentangling
and integrating heat-fusing fiber webs and extra-fine fiber webs
followed by fusing the thus-entangled, heat-fusing fibers (JP-A
3-152255). The wiping material of this type may wipe off light dirt
such as dust or the like but could not remove caked persistent
stains. Another problem is that, when the wiping material is
washed, its surface often fluffs up and some fibers often drop away
from it. In addition, the wiping material is not flexible.
[0005] JP-A 5-56903 discloses a nonwoven fabric for wipers, which
includes mechanically divided extra-fine fibers, which is bulky and
which has a good wiping performance and long-term durability. The
nonwoven fabric for wipers of this type is good for wiping off dust
and the like, but is still unsatisfactory for removing persistent
stains.
[0006] On the other hand, JP-A 6-14860 discloses a nonwoven fabric
for wipers, which comprises mixed fibers of extra-fine fibers and
thick fibers for improving its ability to remove caked stains. JP-A
7-67820 discloses a wiper produced by laminating and entangling
spunlaid webs and paper sheets for improving its washing
resistance. However, these wipers have a tough feel and are not
flexible, and therefore they are not satisfactorily effective for
wiping articles having a three-dimensionally patterned face.
[0007] Based on the above, it is clear that a need exists for a
nonwoven fabric for wipers which has the ability to wipe off even
oily stains and caked persistent stains and which has good washing
resistance.
SUMMARY OF THE INVENTION
[0008] It is an object of the present invention to provide a
nonwoven fabric for wipers which has the ability to wipe off even
oily stains and caked persistent stains, which exhibits excellent
cleaning capabilities on articles with three-dimensionally
patterned faces, and which has good flexibility and good washing
resistance.
[0009] This and other objects have been achieved by the present
invention the first embodiment of which includes a nonwoven fabric,
comprising:
[0010] extra-fine fibers comprising:
[0011] bonded regions in a form selected from the group consisting
of linear bonded regions, dot-like bonded regions and mixtures
thereof, and non-bonded regions on a surface of said extra-fine
fibers;
[0012] wherein said bonded regions account for from 10 to 80% of a
surface area of said nonwoven fabric; and
[0013] wherein a distance between neighboring bonded regions is at
most 20 mm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 shows some examples of the pattern of the gravure
roll that may be used in the present invention. A refers to the
hills of the patterns, B refers to the valleys.
[0015] FIG. 2 shows one example of the surface of the nonwoven
fabric of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Specifically, the present invention provides a nonwoven
fabric for wipers which contains extra-fine fibers comprising,
linear and/or dot-like bonded regions and non-bonded regions on its
surface. The bonded regions account for from 10 to 80% of the
surface area of the nonwoven fabric. The distance between the
neighboring bonded regions is at most 20 mm. The percentage of
bonded regions of surface area includes all values and subvalues
therebetween, especially including 20, 30, 40, 50, 60 and 70%. The
distance between neighboring bonded regions includes all values and
subvalues between 0 and 20 mm, especially including 1, 2, 3, 4, 5,
6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 18 and 19 mm.
[0017] The nonwoven fabric for wipers of the present invention
contains extra-fine fibers. The surface of the nonwoven fabric
comprises linear and/or dot-like bonded regions and non-bonded
regions. Having the bonded regions and the non-bonded regions in
its surface, the nonwoven fabric of the present invention has good
cleaning capabilities and removes not only light dirt such as oily
film or ink stains but also heavy dirt such as caked persistent
stains. The woven fabric gives little fluff, and it is washable for
repeated use.
[0018] Preferably, the single fiber fineness of the extra-fine
fibers is at most 0.5 dtex, more preferably from 0.05 to 0.45 dtex.
The single fiber fineness includes all values and subvalues
therebetween, especially including 0.1, 0.15, 0.2, 0.25, 0.3, 0.35
and 0.4 dtex. The extra-fine fibers may be, for example, directly
spun fibers or those obtained from splittable conjugated fibers.
Preferred are splittable conjugated fibers as extra-fine fibers.
Especially preferable are extra-fine fibers which are prepared by
dividing splittable conjugated fibers each having a nearly circular
cross-sectional profile. This is because the cross-sectional
profile of the extra-fine fibers derived from the splittable
conjugated fibers of this type may have sharp shapes. Therefore,
the nonwoven fabric that contains the extra-fine fibers is
particularly suitable for removing oily stains. Such splittable
conjugated fibers may be mechanically processed by hydroentangling
or by needlepunching or may be chemically processed for dissolution
and removal or for swelling and shrinkage to give the extra-fine
fibers for use in the present invention.
[0019] The splittable conjugated fibers for the present invention
may be formed of at least two different types of resin. The resin
includes, for example, polyester polymers, polyolefin polymers,
polyamide polymers, polystyrene polymers, polyacrylonitrile
polymers, polyvinyl alcohol polymers, and ethylene-vinyl alcohol
copolymers. One or more such polymers may be used for one component
of the fibers, but these are not limiting.
[0020] The polyesters may be fiber-forming polyesters, which are
formed of, for example, aromatic dicarboxylic acids such as
terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic
acid, phthalic acid, .alpha.,.beta.-(4-carboxyphenoxy)ethane,
4,4-dicarboxydiphenyl, 5-sodium sulfoisophthalate; or aliphatic
dicarboxylic acids such as azelaic acid, adipic acid, sebacic acid;
or their esters; and diols such as ethylene glycol, diethylene
glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl
glycol, cyclohexane-1,4-dimethanol, polyethylene glycol,
polytetramethylene glycol. Preferably, at least 80 mol % of the
constituent units of the polyesters are ethylene terephthalate
units.
[0021] The polyamides include, for example, aliphatic polyamides
and semiaromatic polyamides of which the principal component is
nylon 6, nylon 66 or nylon 12. They may contain a minor amount of a
third component.
[0022] The conjugation morphology of these resin components for the
conjugated fibers is not specifically limited. For example, two
resin components may be conjugated:
[0023] 1) into bicomponent fibers having a chrysanthemum-patterned
cross-sectional profile in which the two resin components are
alternately radially aligned;
[0024] 2) into bicomponent fibers having a bimetal-patterned
cross-sectional profile in which the two resin components are
alternately layered; or,
[0025] 3) into those having a sea/island patterned cross-sectional
profile in which islands of one resin component are dispersed in a
sea matrix of the other resin component. Of the splittable
conjugated fibers, the chrysanthemum-patterned fibers and
bimetal-patterned fibers are preferred for use herein, since the
extra-fine fibers derived from them may have a sharp
cross-sectional profile and therefore they are more effective for
wiping off stains, especially for wiping off oily stains.
[0026] In the present invention, heat-fusing fibers may also be
used. Due to the heat-fusing fibers, the shape stability of the
nonwoven fabric according to the present invention is improved.
Preferably, the proportion of the extra-fine fibers in the nonwoven
fabric that contain heat-fusing fibers is at least 50%, preferably
at least 60%, more preferably as least 70%, most preferably at
least 80%. If it is smaller than 50%, the wiping capability of the
nonwoven fabric will worsen. Especially when the nonwoven fabric is
used for wiping off oily stains, the proportion of the splittable
conjugated fibers therein is at least 80%, preferably at least 85%,
more preferably at least 90% and most preferably 95%. Here, the
heat-fusing fibers may be those of a single component, but are
preferably side-by-side type or core-sheath type heat-fusing
conjugated fibers of at least two resin components including those
not fusing in heat treatment, since the non-fusing part of the
fibers acts to retain the fiber strength. It is preferable that the
melting point difference between the extra-fine fibers and the
heat-fusing fibers that constitute the nonwoven fabric is at least
10.degree. C., preferably at least 15.degree. C., more preferably
at least 20.degree. C. and most preferably at least 25.degree. C.,
so that the extra-fine fibers do not fuse with the heat-fusing
fibers.
[0027] For the component for the heat-fusing fibers, various
combinations may be mentioned, including, for example,
6-nylon/polyethylene, polypropylene/polyethylene,
polypropylene/ethylene-vinyl acetate copolymer,
polyester/polypropylene, polyester/polyethylene, 6-nylon/66-nylon;
and high-density polyester/low-density polyester, but these are not
limiting.
[0028] The nonwoven fabric for wipers of the present invention
contains the extra-fine fibers mentioned above. For realizing
excellent oil-removing capabilities and flexibility thereof, it is
more preferable that the nonwoven fabric comprises 100% extra-fine
fibers. The other fibers that may be combined with the extra-fine
fibers in the present invention are not specifically limited, and
may be any of various natural fibers and synthetic fibers.
[0029] The method of producing the nonwoven fabric for wipers of
the invention is not specifically limited. For example, the
nonwoven fabric may be formed of fiber webs that are prepared
according to drylaying of carding, air-laying, spun-bonding or to
wet-laying. The fiber webs are preferably random-laid webs,
semirandom-laid webs or parallel-laid webs.
[0030] In the present invention, it is especially preferable that
the fiber webs are formed by mixing various fibers such as
extra-fine fibers and heat-fusing fibers mentioned above followed
by processing them into fiber webs according to a carding process
or an air-laying process.
[0031] In case where the extra-fine fibers are derived from
splittable conjugated fibers by mechanically dividing them, the
splittable conjugated fibers may be processed into the intended
extra-fine fibers before they are formed into fiber webs. However,
it is preferable that the splittable conjugated fibers are formed
into fiber webs. After the resulting fiber webs are layered, they
are mechanically processed by needle-punching or water-jet
treatment, whereby the splittable conjugated fibers in the layered
webs are divided to give the intended extra-fine fibers therein and
the resulting extra-fine fibers are entangled at the same time
through the treatment. In this process, the fiber-to-fiber bonding
in the nonwoven fabric produced may be more strengthened.
[0032] The nonwoven fabric for wipers of the present invention has,
in its surface, linear and/or dot-like bonded regions and
non-bonded regions, and therefore has the ability to wipe off
various dirt. Specifically, the non-bonded regions of the nonwoven
fabric act to wipe off light dirt such as oily stains, and the
bonded regions thereof act to wipe off caked persistent stains.
Therefore, the nonwoven fabric exhibits its ability to wipe off
various types of dirt. In the bonded regions, the fibers are partly
fixed and are harder than those in the non-bonded regions.
Therefore, the fibers in these regions are more effective for
wiping off persistent stains. In addition, the bonded regions
enhance the wiping performance with the nonwoven fabric. Due to
having the fixed and toughened, bonded regions, the nonwoven fabric
is, as a whole, toughened in some degree and it fits well to the
hand while used for wiping operation. In addition, the nonwoven
fabric also has the non-bonded regions and it keeps its softness.
Accordingly, the nonwoven fabric well follows even
three-dimensionally patterned faces of the articles to be cleaned
with it.
[0033] Preferably, the bonded regions account for from 10 to 80% of
the surface area of the nonwoven fabric. If the area of the bonded
regions exceeds 80%, the nonwoven fabric will be too hard, and its
feel to the hand and its wiping performance will worsen. In
addition, the extra-fine fibers that are effective for wiping off
light dirt such as oily stains will be covered with resin, and, as
a result, the oil-wiping capability of the nonwoven fabric will
worsen. On the other hand, if the area of the bonded regions is
smaller than 10%, the fibers could not be satisfactorily fixed, and
the surface of the nonwoven fabric will readily fluff up. If so,
the nonwoven fabric could not resist to external physical shock
such as washing, and the nonwoven fabric will be readily deformed
and could not be used repeatedly. For better wiping capability,
surface fluffing resistance and washing resistance of the nonwoven
fabric, the bonded regions preferably account for from 10 to 50%,
more preferably from 10 to 40% of the surface area of the nonwoven
fabric.
[0034] The bonded regions of the nonwoven fabric may be formed by
the use of a resin binder. For example, an emulsion resin binder
may be used. The binder resin includes, for example, acrylic
resins, acrylate copolymer resins, polyurethane resins, vinyl
acetate copolymer resins, epoxy resins and styrene-acrylic
copolymer resins, but is not limited to them.
[0035] The method of forming the bonded regions is not specifically
limited. For example, the layered fiber webs may be partly bonded
by emboss-rolling, or a resin binder may be transferred onto them
through gravure-rolling. In the present invention, when a gravure
roll is used, it is preferable that a pattern of continuous lines
is formed. For example, the patterns of (I) to (III) in FIG. 1 are
preferred as they improve the wiping capability and the design of
the nonwoven fabric. In addition, it is desirable that at least a
part of the fibers in the non-bonded regions of the nonwoven fabric
may be embedded in the bonded regions for further improving the
washing resistance of the nonwoven fabric. For this, the bonded
regions are so formed that the distance between the neighboring
bonded regions can be at most 20 mm, preferably at most 10 mm, more
preferably from 2 to 8 mm.
[0036] In the present invention, the bonded regions may be formed
to have a dot-like pattern of, for example, (IV) to (V) of FIG. 1.
Having the pattern, the nonwoven fabric may be more flexible, and
its ability to wipe off oily stains may be improved. The bonded
regions may be a combination of the linear pattern and the dot-like
pattern mentioned above, and various patterns may be employed for
the bonded regions in accordance with the object thereof.
[0037] The binder having permeated through the thickness of the
nonwoven fabric for wipers may be localized around both faces of
the nonwoven fabric or may be uniformly permeated through the depth
of the nonwoven fabric, depending on the drying condition after the
binder resin application.
[0038] In any case where the binder resin has been localized around
both faces of the nonwoven fabric or uniformly permeated through
the depth thereof, the nonwoven fabric is prevented from fluffing
up and its washing resistance is good. However, the binder resin
localized around the faces of the nonwoven fabric is more effective
for increasing the surface strength of the nonwoven fabric and for
enhancing the wiping capability thereof to remove persistent
strains. In this case the nonwoven fabric is soft and may fit well
to the hand, and it may follow well even three-dimensionally
patterned faces of the articles to be cleaned with it. To that
effect, the wiping capability of the nonwoven fabric of the type is
better.
[0039] In the nonwoven fabric for wipers of the present invention,
it is preferable that at least a part of the individual fibers in
the non-bonded regions are fixed by the bonded regions. Concretely,
some fibers in the non-bonded regions of the nonwoven fabric are
embedded in the bonded regions and are thereby fixed. In that
condition, the nonwoven fabric well keeps its soft feel and its
wiping capability, does not tend to exhibit so much fluffing, and
its washing resistance is good. The nonwoven fabric of this type is
most preferable for wipers.
[0040] The nonwoven fabric for wipers of the present invention has
the above-mentioned, linear and/or dot-like bonded regions. For
better wiping capability and better washing resistance of the
nonwoven fabric, the bonded regions are so formed that the distance
between the neighboring bonded regions can be at most 20 mm,
preferably 2 to 10 mm. The distance between the neighboring bonded
regions includes all values and subvalues therebetween, especially
including 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18
and 19 mm. If the distance between the neighboring bonded regions
is larger than 20 mm, the dimensional stability of the nonwoven
fabric will be lower and the washing resistance thereof will also
be lower. On the other hand, if the distance between them is
smaller than 2 mm, the nonwoven fabric will have a hard feel. For
keeping the oil-wiping capability of the extra-fine fibers as such
and for ensuring better washing resistance of the nonwoven fabric,
the distance between the neighboring bonded regions is most
preferably from 2 to 8 mm. The distance between the neighboring
bonded regions referred to in the present invention is the shortest
distance therebetween, and it is obtained by measuring the shortest
distance between the ends of the neighboring bonded regions.
[0041] The surface of the nonwoven fabric for wipers of the present
invention may be flat, but is preferably further processed to have
a perforated or embossed pattern for further enhancing the wiping
capability of the nonwoven fabric. Specifically, owing to the
synergistic effect of the embossed pattern and the bonded regions
in the surface of the nonwoven fabric, the wiping capability of the
nonwoven fabric is further improved. Another advantage thereof is
that the nonwoven fabric thus having such an embossed surface well
follows even three-dimensionally patterned faces of the articles to
be wiped with it. The nonwoven fabric exhibits its wiping effect
and, in addition, it is believed that the extra-fine fibers could
more readily adhere to the surface of the nonwoven fabric to act to
wipe off light dirt such as oily stains. In order to introduce an
embossed pattern on the surface of the nonwoven fabric,
hydroentangling can be employed. This method comprises spreading
fiber webs on a belt support of a meshed resin net or metal net
followed by applying water jets to them to thereby make the
constituent fibers entangled. In this process, the height
difference between the knuckles of the weft and those of the warp
of the mesh belt is transferred onto the nonwoven fabric webs, and
the nonwoven fabric thus processed is to have the intended embossed
pattern on its surface. Alternatively, an embossing roll can be
applied to the nonwoven fabric under pressure to thereby make the
nonwoven fabric have the intended embossed pattern. In the present
invention, hydroentangling is preferred because the resulting
nonwoven fabric has a soft feel and keeps the embossed pattern
well, even after washing. The nonwoven fabric having an embossed
pattern may also be processed with a binder resin or the like to
form the bonded regions therein.
[0042] The above-mentioned embossed pattern may be formed according
to the methods mentioned hereinabove. For example, a nonwoven
fabric having a pattern as in FIG. 2 may be used in the present
invention. In a case where the nonwoven fabric having an embossed
pattern is used in the present invention, it is preferable that the
height difference between the hills and the valleys of the pattern
is at least 20% of the thickness of the nonwoven fabric. If having
a height difference of at least 20%, the surface area of the
nonwoven fabric increases and therefore the length of contact with
dirt is prolonged. Furthermore, the nonwoven fabric is more easily
handled when used for wiping off dirt. In addition, the dirt to be
wiped off may be physically caught by the hills of the embossed
pattern of the nonwoven fabric and it may therefore well adhere to
the nonwoven fabric. For these reasons, the wiping capability of
the nonwoven fabric is much more enhanced. Moreover, some dirt may
be kept caught in the valleys of the nonwoven fabric, and does not
move to other articles that are cleaned with the nonwoven fabric to
stain them. If the height difference is smaller than 20%, the
surface of the nonwoven fabric will be flat, and if so, the
nonwoven fabric could not well catch dirt and its wiping capability
is inferior. The dirt once caught by the nonwoven fabric will move
to other articles to stain them.
[0043] In the present invention, it is further preferable that the
hills are formed to be both in the bonded regions and the
non-bonded regions. The hills improve the wiping capability of the
nonwoven fabric to well follow even the surfaces of non-flat
articles to be wiped with it. In addition, the nonwoven fabric has
much improved washing resistance. Moreover, the hills overlap with
the bonded regions, and they are more hardened as the constituent
fibers are concentrated therein. Accordingly, the thus-hardened
hills are more effective for wiping off persistent stains.
[0044] As so mentioned hereinabove, the nonwoven fabric for wipers
of this invention has bonded regions in which the surface of the
nonwoven fabric is prevented from fluffing up. Even after washing,
the entangled points of the constituent fibers of the nonwoven
fabric do not shift and the nonwoven fabric can be used repeatedly.
In a case where extra-fine fibers having edges are used, the
nonwoven fabric is effective even for wiping off extremely fine
dirt. The advantage of said nonwoven fabric is that it may well
catch such fine dirt and may readily hold it on its surface.
[0045] The nonwoven fabric of the invention is usable for various
wipers, which are, for example, for wiping noble metal articles
such as jellies and for wiping dishes, tables, glass articles,
electric appliances, furniture, gas cookers, etc.
[0046] The wipers to be obtained in the present invention are
highly resistant to washing and can be used repeatedly, and
therefore they are economical.
[0047] Having generally described this invention, a further
understanding can be obtained by reference to certain specific
examples which are provided herein for purposes of illustration
only, and are not intended to be limiting unless otherwise
specified.
EXAMPLES
[0048] In the Examples, the physical properties were measured
according to the methods mentioned below.
[0049] Procedure of Measuring the Thickness of the Nonwoven
Fabric:
[0050] The thickness of a sample is measured at 10 points under a
load of 12 gf/cm.sup.2, and the data are averaged.
[0051] Height Difference in Embossed Pattern of Nonwoven
Fabric:
[0052] A CCD laser dislocation sensor, LK-2000 (by Keyence) is
used. With no load applied thereto, the thickness of a sample is
measured at 6 hill peaks and 6 valley bottoms thereof. The data are
averaged, and the difference between the two averages is divided by
the thickness of the hill peaks. This indicates the height
difference.
Example 1
[0053] Splittable conjugated fibers having a cross-sectional
profile of alternately-layered nylon 6 and polyethylene
terephthalate; (Kuraray's WRAMP, having a fineness of 3.8 dtex and
a fiber length of 51 mm) alone (100%) were fed into a carding
machine and processed into fiber webs. The resulting webs were
processed by hydroentangling whereby the constituent fibers were
divided into extra-fine fibers and the thus-split extra-fine fibers
were entangled. After being processed by hydroentangling, the webs
were coated with an acrylic resin (by Nippon Carbide) with a
gravure roll having a waved pattern of II in FIG. 1. The area ratio
of the pattern was 13%, the binder pitch was 3.2 mm, and the binder
amount was 2 g/m.sup.2. The process gave a nonwoven fabric for
wipers, having a mass per unit area of 80 g/m.sup.2. The nonwoven
fabric was observed, and was found to have linear bonded regions
formed of the acrylic resin and non-bonded regions. The nonwoven
fabric was observed in more detail, and it was confirmed that some
ends of the extra-fine fibers in the non-bonded regions were
embedded in the bonded regions and were fixed therein. The distance
between the neighboring bonded regions was 3.0 mm. The data of the
nonwoven fabric are given in Table 1.
Example 2
[0054] A nonwoven fabric for wipers having a mass per unit area of
80 g/m.sup.2 was produced in the same manner as in Example 1 except
for the following changes: The webs obtained in Example 1 were
processed by hydroentangling on a herringbone-patterned net so that
the net pattern was transferred onto the webs, and the webs
therefore had the embossed herringbone pattern. Thus obtained, the
nonwoven fabric was observed, and was found to have linear bonded
regions formed of the acrylic resin and non-bonded regions.
[0055] The nonwoven, fabric was observed in more detail, and it was
confirmed that some ends of the extra-fine fibers in the non-bonded
regions were embedded in the bonded regions and were fixed therein.
The distance between the neighboring bonded regions was 3.0 mm. See
Table 1.
Example 3
[0056] A nonwoven fabric for wipers having a unit weight of 80
g/m.sup.2 was produced in the same manner as in Example 2 except
for the following changes: Splittable conjugated fibers having a
cross-sectional profile of alternately-layered nylon 6 and
polyethylene terephthalate (Kuraray's WRAMP, having a fineness of
3.8 dtex and a fiber length of 51 mm) 85% and core/sheath
bicomponent binder fibers of which the core is polypropylene and
the sheath is polyethylene (Daiwabo's NBF (H), 2. 2 dtex, 51 mm)
15% were fed into a carding machine and processed into fiber webs.
The resulting webs were processed by hydroentangling whereby the
splittable fibers were divided into extra-fine fibers and the
resulting fibers were entangled. Thus processed, the webs were
heat-set and the binder fibers therein were thereby fused. The
distance between the neighboring bonded regions in the nonwoven
fabric thus produced was 3.0 mm. See Table 1.
Comparative Example 1
[0057] A nonwoven fabric for wipers having a mass per unit area of
80 g/m.sup.2 was produced in the same manner as in Example 2, to
which, however, the acrylic resin was not applied. See Table 1.
Comparative Example 2
[0058] A nonwoven fabric for wipers having a mass per unit area of
80 g/m.sup.2 was produced in the same manner as in Example 3, to
which, however, the acrylic resin was not applied. See Table 1.
Comparative Example 3
[0059] Splittable conjugated fibers having a
chrysanthemum-patterned cross-sectional profile of radially-aligned
nylon 6 and polyethylene terephthalate (having a fineness of 2.2
dtex and a fiber length of 38 mm) 40% and polyethylene
terephthalate fibers (having a fineness of 16.5 dtex and a fiber
length of 51 mm) 60% were fed into a carding machine and processed
into fiber webs. The resulting fibers webs were sprayed with an
acrylic emulsion (15 g/m.sup.2 in terms of the solid content of the
emulsion), and then heat-set at 150.degree. C. for 3 minutes
whereby the constituent fibers were bonded to each other to give a
nonwoven fabric for wipers. See Table 1.
1 TABLE 1 mass per Bonded unit area Thickness Regions Height
Difference (%) (g/m.sup.2) (mm) (%) in Embossed Pattern Example 1
80 0.54 13 15 Example 2 80 0.52 13 38 Example 3 80 0.51 13 33 Comp.
Ex. 1 80 0.57 0 41 Comp. Ex. 2 80 0.54 0 39 Comp. Ex. 3 150 2.6 100
10
[0060] The nonwoven fabrics for wipers obtained in the
above-mentioned Examples and Comparative Examples were worked into
wipers, and evaluated in the manner mentioned below. The results
are given in Table 2.
[0061] Procedure for the Evaluation of Fluffing Resistance:
[0062] 0.1 g of water is dropped onto a mirror face through a
syringe. A wiper sample of 15 cm.times.15 cm is folded in four. An
operator carries the wiper sample in the hand, and circularly moves
it 10 times on the mirror face to wipe up the water. Then, the thus
wiped mirror face is checked for the fiber remains thereon from the
wiper sample. The wiper sample is evaluated in 5 ranks as
follows:
[0063] 5: No fluff found.
[0064] 4: 1 to 5 fiber remains found.
[0065] 3: 6 to 25 fiber remains found.
[0066] 2: 26 to 50 fiber remains found.
[0067] 1: 51 or more fiber remains found.
[0068] Procedure for Evaluation of Washing Resistance:
[0069] A square of 20 cm.times.20 cm is marked on a wiper sample,
and the sample is washed 5 times according to the washing test
method of JIS L1096. After washing, the shrinkage percentage of the
sample is measured. Based on the CD (cross direction) shrinkage
percentage thereof, the sample is evaluated in 3 ranks as
follows:
[0070] A: less than +/-3%.
[0071] B: +/-3% to 5%.
[0072] C: more than +/-5%.
[0073] Procedure for Evaluation of Wiping Capability to Remove Oily
Stains:
[0074] On a glass sheet, a circular seal is impressed with oily
ink. A wiper sample of 15 cm.times.15 cm is folded in four. An
operator carries the wiper sample in the hand, and completely wipes
off the oily film with the wiper sample. The number of wiping
operations that has been done before the film is completely wiped
off is counted.
[0075] Procedure for Evaluation of Wiping Capability to Remove
Persistent Stains:
[0076] The absorbance (A) of a glass sheet is measured. Moriwiper
(by Sumiko Lubricant) is circularly applied to the glass sheet, and
dried. After drying, the absorbance (B) of the glass sheet is
measured. The glass sheet is set on the sample stand of a rubbing
fastness tester. A wiper sample having a controlled water content
of 100% is fitted to the friction prove of the tester, and this is
moved once back and forth on the glass sheet to wipe off the stain.
After this, the absorbance (C) of the glass sheet is measured.
[0077] According to the following equation, the degree of stain
removal is obtained.
Degree of stain removal=(C-B)/(A-B).times.100.
[0078] Procedure for Evaluation of Feel:
[0079] The feel of each wiper sample in the hand is evaluated in 3
ranks as follows:
[0080] A: Soft to the hand.
[0081] B: A little hard to the hand.
[0082] C: Hard to the hand.
2 TABLE 2 Oil Stains Persistent Fluffing Washing Wiping Stains
Wiping Resistance Resistance Capability Capability Feel Example 1 5
A 9 56.4 A Example 2 5 A 9 57.0 A Example 3 5 A 8 51.2 A to B Comp.
2 C 8 6.6 B Example 1 Comp. 3 B 9 10.2 B Example 2 Comp. 3 to 4 B 7
16.4 C Example 3
[0083] As is shown in Table 2, it is understood that the wipers
formed of the nonwoven fabric of the present invention have good
wiping capabilities and washing resistance.
[0084] As described in detail with reference to its preferred
embodiments, the nonwoven fabric of the present invention exhibits
excellent wiping capabilities to remove any and every dirt
including oily stains and persistent stains under any cleaning
conditions. While used for wiping off dirt, the wipers formed of
the nonwoven fabric fluff up little. As their washing resistance is
good, the wipers are repeatedly usable.
[0085] Japanese patent application 31914/2002, filed Feb. 8, 2002,
is incorporated herein by reference.
[0086] Numerous modifications and variations on the present
invention are possible in light of the above teachings. It is
therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described herein.
* * * * *