U.S. patent application number 14/131352 was filed with the patent office on 2014-05-22 for articles including multi-component fibers and particles and methods of making and using the same.
The applicant listed for this patent is Michael D. Crandall, Ignatius A. Kadoma, Andrew J. Peterson, Bruce A. Sventek, Yong K. Wu. Invention is credited to Michael D. Crandall, Ignatius A. Kadoma, Andrew J. Peterson, Bruce A. Sventek, Yong K. Wu.
Application Number | 20140138305 14/131352 |
Document ID | / |
Family ID | 47437431 |
Filed Date | 2014-05-22 |
United States Patent
Application |
20140138305 |
Kind Code |
A1 |
Crandall; Michael D. ; et
al. |
May 22, 2014 |
ARTICLES INCLUDING MULTI-COMPONENT FIBERS AND PARTICLES AND METHODS
OF MAKING AND USING THE SAME
Abstract
An article including multi-component fibers and particles is
disclosed. The multi-component fibers include at least a first
polymeric composition and a second polymeric composition, are
adhered together, and are non-fusing at a temperature of at least
110.degree. C. At least a portion of the external surfaces of the
multi-component fibers includes the first polymeric composition.
Particles are adhered or directly attached to the first polymeric
composition on the external surfaces of at least some of the
multi-component fibers along their lengths. The particles include
at least one of activated carbon, superabsorbent polymer particles,
and abrasive particles. In some embodiments, the particles are
distributed throughout the thickness of a web of the
multi-component fibers. A method of making the articles is also
disclosed.
Inventors: |
Crandall; Michael D.; (North
Oaks, MN) ; Kadoma; Ignatius A.; (Cottage Grove,
MN) ; Peterson; Andrew J.; (White Bear Lake, MN)
; Sventek; Bruce A.; (Woodbury, MN) ; Wu; Yong
K.; (Woodbury, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Crandall; Michael D.
Kadoma; Ignatius A.
Peterson; Andrew J.
Sventek; Bruce A.
Wu; Yong K. |
North Oaks
Cottage Grove
White Bear Lake
Woodbury
Woodbury |
MN
MN
MN
MN
MN |
US
US
US
US
US |
|
|
Family ID: |
47437431 |
Appl. No.: |
14/131352 |
Filed: |
July 5, 2012 |
PCT Filed: |
July 5, 2012 |
PCT NO: |
PCT/US2012/045492 |
371 Date: |
January 7, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61505165 |
Jul 7, 2011 |
|
|
|
Current U.S.
Class: |
210/502.1 ;
264/126; 442/334; 442/411; 51/298 |
Current CPC
Class: |
D04H 1/4382 20130101;
D04H 1/413 20130101; D04H 1/4334 20130101; D04H 1/4358 20130101;
D04H 3/147 20130101; Y10T 442/692 20150401; B01D 2239/1216
20130101; D06M 23/08 20130101; B24B 37/245 20130101; B01D 2239/0618
20130101; B24D 3/34 20130101; D04H 1/435 20130101; Y10T 442/608
20150401; D04H 1/541 20130101; B24D 11/02 20130101; C09K 3/1409
20130101 |
Class at
Publication: |
210/502.1 ;
442/411; 442/334; 51/298; 264/126 |
International
Class: |
D04H 1/541 20060101
D04H001/541; B24D 11/02 20060101 B24D011/02 |
Claims
1. An article comprising: multi-component fibers having external
surfaces and comprising at least a first polymeric composition and
a second polymeric composition, wherein at least a portion of the
external surfaces of the multi-component fibers comprises the first
polymeric composition, and wherein the multi-component fibers are
adhered together and are non-fusing at a temperature of at least
110.degree. C.; and particles adhered at least to the first
polymeric composition on the external surfaces of at least some of
the multi-component fibers along their lengths, wherein the
particles comprise at least one of activated carbon or
superabsorbent polymer particles.
2. An article comprising: a web of multi-component fibers having
external surfaces and comprising at least a first polymeric
composition and second polymeric composition, wherein at least a
portion of the external surfaces of the multi-component fibers
comprises the first polymeric composition, and wherein the
multi-component fibers are adhered together and are non-fusing at a
temperature of at least 110.degree. C.; and particles directly
attached to the first polymeric composition on the external
surfaces of at least some of the multi-component fibers along their
lengths, wherein the particles comprise at least one of activated
carbon, superabsorbent polymer particles, or abrasive particles,
and wherein the particles are distributed throughout the thickness
of the web.
3. The article of claim 2, wherein the article is an abrasive
article, wherein the particles are abrasive particles, and wherein
the abrasive article does not include a size coat.
4. The article of claim 2, wherein the particles are abrasive
particles comprising cerium oxide.
5. The article of claim 1, wherein the article is a filter
comprising activated carbon.
6. The article of claim 2, wherein the first polymeric composition
has a softening temperature of up to 150.degree. C., wherein the
second polymeric composition has a melting point of at least
130.degree. C., and wherein the difference between the softening
temperature of the first polymeric composition and the melting
point of the second polymeric composition is at least 10.degree.
C.
7. The article of claim 2, wherein the first polymeric composition
has an elastic modulus of less than 3.times.10.sup.5 N/m.sup.2 at a
temperature of at least 80.degree. C. measured at a frequency of
one hertz.
8. The article of claim 2, wherein the multi-component fibers are
in a range from 10 micrometers to 300 micrometers in diameter and
in a range from 3 millimeters to 60 millimeters in length.
9. The article of claim 2, wherein the multi-component fibers are
non-fusing at a temperature of at least 150.degree. C.
10. The article of claim 2, further comprising other, different
fibers.
11. The article of claim 2, wherein the particles have an average
size up to twenty-five micrometers.
12. A method of making an article, the method comprising: providing
a mixture of particles and multi-component fibers, the
multi-component fibers comprising at least a first polymeric
composition and a second polymeric composition, and the particles
comprising at least one of activated carbon, superabsorbent polymer
particles, or abrasive particles; and heating the mixture to a
temperature at which the multi-component fibers are non-fusing and
at which the first polymeric composition has an elastic modulus of
less than 3.times.10.sup.5 N/m.sup.2 when measured at a frequency
of one hertz, wherein at least a portion of the mixture becomes
adhered together to form a web, and wherein the particles are
dispersed throughout the thickness of the web.
13. The method of claim 12, wherein the temperature is at least
80.degree. C.
14. The method of claim 12, wherein the first polymeric composition
has a softening temperature of up to 150.degree. C., wherein the
second polymeric composition has a melting point of at least
130.degree. C., and wherein the difference between the softening
temperature of the first polymeric composition and the melting
point of the second polymeric composition is at least 10.degree.
C.
15. The method of claim 12, wherein the article is a filter
comprising activated carbon, or wherein the article is an abrasive
article.
16. The article of claim 1, wherein the article is a filter
comprising activated carbon.
17. The article of claim 1, wherein the first polymeric composition
has a softening temperature of up to 150.degree. C., wherein the
second polymeric composition has a melting point of at least
130.degree. C., and wherein the difference between the softening
temperature of the first polymeric composition and the melting
point of the second polymeric composition is at least 10.degree.
C.
18. The article of claim 1, wherein the first polymeric composition
has an elastic modulus of less than 3.times.10.sup.5 N/m.sup.2 at a
temperature of at least 80.degree. C. measured at a frequency of
one hertz.
19. The article of claim 1, wherein the multi-component fibers are
in a range from 3 millimeters to 60 millimeters in length.
20. The article of claim 1, further comprising other, different
fibers.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional
Application No. 61/505,165, filed Jul. 7, 2011, the disclosure of
which is incorporated by reference in its entirety herein.
BACKGROUND
[0002] Various multi-component fibers are known. Examples include
fibers that have a low temperature melting or softening sheath
covering a higher melting core. Multi-component structures may be
useful, for example, for fiber bonding, wherein the sheath, for
example, when melted or softened serves as a bonding agent for the
core.
[0003] Some articles including fibers and particles are known. In
some cases, such articles are made from multi-component fibers
where one component melts and coalesces. In these cases, the
particles are located at the junction points where fibers contact
one another. See, for example, International Patent Application
Publication No. WO 2010/045053 (Coant et al.).
[0004] Some abrasive articles including multi-component fibers and
abrasive particles have been described. See, for example, U.S. Pat.
No. 5,082,720 (Hayes); U.S. Pat. No. 5,972,463 (Martin et al.); and
U.S. Pat. No. 6,017,831 (Beardsley et al.). Typically, make coats
and/or size coats are used to hold particles on a surface of a web
of the fibers.
SUMMARY
[0005] The present disclosure provides, for example, articles
including multi-component fibers and particles. The multi-component
fibers are non-fusing at a temperature of at least 110.degree. C.,
which means the fibers maintain their multi-component architecture
at least up to that temperature. The particles adhere to a first
polymeric composition in the multi-component fibers along the
length of the fibers. Therefore, the particles are not located only
in the junction points between fibers but may be uniformly
distributed. In the method of making the articles disclosed herein,
a mixture of fibers and particles is heated to a temperature where
the first polymeric composition has an elastic modulus of less than
3.times.10.sup.5 N/m.sup.2 when measured at one hertz. At such a
temperature, the first polymeric composition becomes tacky and
adheres the particles on the lengths of the multi-component
fibers.
[0006] In one aspect, the present disclosure provides an article
including multi-component fibers and particles. The multi-component
fibers have external surfaces and include at least a first
polymeric composition and a second polymeric composition, with at
least a portion of the external surfaces of the multi-component
fibers comprising the first polymeric composition. The
multi-component fibers are adhered together and are non-fusing at a
temperature of at least 110.degree. C. The particles are adhered at
least to the first polymeric composition on the external surfaces
of at least some of the multi-component fibers along their lengths.
The particles comprise at least one of activated carbon and
superabsorbent polymer particles.
[0007] In another aspect, the present disclosure provides an
article including a web of multi-component fibers and particles
distributed throughout the thickness of the web. The
multi-component fibers have external surfaces and include at least
a first polymeric composition and a second polymeric composition,
with at least a portion of the external surfaces of the
multi-component fibers comprising the first polymeric composition.
The multi-component fibers are adhered together and are non-fusing
at a temperature of at least 110.degree. C. The particles are
directly attached to the first polymeric composition on the
external surfaces of at least some of the multi-component fibers
along their lengths. The particles comprise at least one of
activated carbon, superabsorbent polymer particles, and abrasive
particles.
[0008] In another aspect, the present disclosure provides a method
of making an article. The method includes providing a mixture of
particles and multi-component fibers. The multi-component fibers
include at least a first polymeric composition and a second
polymeric composition, and the particles include at least one of
activated carbon, superabsorbent polymer particles, and abrasive
particles. The method further includes heating the mixture to a
temperature at which the multi-component fibers are non-fusing and
at which the first polymeric composition has an elastic modulus of
less than 3.times.10.sup.5 N/m.sup.2 when measured at one hertz.
When heated to such a temperature, at least a portion of the
mixture becomes adhered together to form a web, and the particles
are dispersed throughout the thickness of the web.
[0009] In some embodiments of the foregoing aspects, the particles
include activated carbon. In these embodiments, the articles
described herein are useful, for example, for filtration. Carbon
filters as articles according to and/or made according to the
present disclosure are typically easy and inexpensive to assemble
without the use of sophisticated equipment. Such filters are
typically flexible, which may be advantageous for some
configurations, with the activated carbon particles being strongly
adhered to the multi-component fibers.
[0010] In other embodiments of the foregoing aspects, the particles
include abrasive particles, and the articles described herein are
useful as abrasive articles. In these embodiments, the articles are
surprisingly effective as abrasives even in the absence of make
coats and size coats. Abrasive articles according to the present
disclosure are typically prepared without much loss of the abrasive
particles.
[0011] In this application, terms such as "a", "an" and "the" are
not intended to refer to only a singular entity, but include the
general class of which a specific example may be used for
illustration. The terms "a", "an", and "the" are used
interchangeably with the term "at least one". The phrases "at least
one of" and "comprises at least one of" followed by a list refers
to any one of the items in the list and any combination of two or
more items in the list. All numerical ranges are inclusive of their
endpoints and non-integral values between the endpoints unless
otherwise stated.
[0012] The above summary of the present disclosure is not intended
to describe each disclosed embodiment or every implementation of
the present disclosure. The description that follows more
particularly exemplifies illustrative embodiments. It is to be
understood, therefore, that the drawings and following description
are for illustration purposes only and should not be read in a
manner that would unduly limit the scope of this disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] For a more complete understanding of the features and
advantages of the present disclosure, reference is now made to the
detailed description along with the accompanying figures and in
which:
[0014] FIG. 1 is a partial schematic view of an exemplary article
according to the present disclosure;
[0015] FIGS. 2A-2D are schematic cross-sections of four exemplary
fibers described herein;
[0016] FIGS. 3A-3E are schematic perspective views of various
fibers described herein;
[0017] FIGS. 4A and 4B are photomicrographs of exemplary articles
according to the present disclosure, in which activated carbon is
adhered to the surfaces of multi-component fibers; and
[0018] FIG. 5 is a photograph of the patterned abrasive article of
Example 2.
DETAILED DESCRIPTION
[0019] FIG. 1 illustrates a portion of an exemplary article
according to and/or made according to the present disclosure. The
article includes multi-component fibers 4 and particles 2. The
multi-component fibers are adhered together (e.g., autogenously
bonded) at junction points 6, and the particles 2 are adhered on
the external surfaces of at least some of the multi-component
fibers 4. As illustrated in FIG. 1, the particles 2 are located
along the lengths of the multi-component fibers 4, which means that
the particles are not located only at the junction points 6 of the
fibers.
[0020] In some embodiments, particles located "along the lengths"
of the multi-component fibers means that the particles are located
substantially along the entire length of the multi-component
fibers. The particles may be randomly distributed along the entire
length of the multi-component fibers. In these embodiments, the
particles need not cover the entire external surface of the
multi-component fibers to be considered to be located along the
entire length of the multi-component fibers. The particles may be
uniformly distributed, or not, depending, for example, on the level
of mixing of the multi-component fibers and the particles, as
described below, and the particle size distribution.
[0021] In some embodiments, including the embodiment illustrated in
FIG. 1, the particles 2 are directly attached to the external
surfaces of at least some of the multi-component fibers 4.
"Directly attached" means that there is no adhesive or other binder
between the particles and the first polymeric composition on the
external surface of the fibers. The first polymeric composition in
the multi-component fibers typically functions as the adhesive that
holds the fibers together and adheres the particles to the
fibers.
[0022] Fibers useful for the articles disclosed herein include a
variety of cross-sectional shapes. Useful fibers include those
having at least one cross-sectional shape selected from the group
consisting of circular, prismatic, cylindrical, lobed, rectangular,
polygonal, or dog-boned. The fibers may be hollow or not hollow,
and they may be straight or have an undulating shape. Differences
in cross-sectional shape allow for control of active surface area,
mechanical properties, and interaction with particles or other
components. In some embodiments, the fiber according to the present
disclosure has a circular cross-section or a rectangular
cross-section. Fibers having a generally rectangular cross-section
shape are also typically known as ribbons. Fibers are useful, for
example, because they provide large surface areas relative the
volume they displace.
[0023] Exemplary embodiments of multi-component fibers useful for
practicing the present disclosure include those with cross-sections
illustrated in FIGS. 2A-2D. A core-sheath configuration, as shown
in FIG. 2B or 2C, may be useful, for example, because of the large
surface area of the sheath. In these configurations, the external
surface of the fiber is typically made from a single composition.
It is within the scope of the present disclosure for the
core-sheath configurations to have multiple sheaths. Other
configurations, for example, as shown in FIGS. 2A and 2D provide
options that can be selected depending on the intended application.
In the segmented pie wedge (see, e.g., FIG. 2A) and the layered
(see, e.g., FIG. 2D) configurations, typically the external surface
is made from more than one composition.
[0024] Referring to FIG. 2A, a pie-wedge fiber 10 has a circular
cross-section 12, a first polymeric composition located in regions
16a and 16b, and a second polymeric composition located in regions
14a and 14b. Other regions in the fiber (18a and 18b) may include a
third component (e.g., a third, different polymeric composition) or
may independently include the first polymeric composition or the
second polymeric composition.
[0025] In FIG. 2B, fiber 20 has circular cross-section 22, sheath
24 of a first polymeric composition, and core 26 of a second
polymeric composition. FIG. 2C shows fiber 30 having a circular
cross-section 32 and a core-sheath structure with sheath 34 of a
first polymeric composition and plurality of cores 36 of a second
polymeric composition.
[0026] FIG. 2D shows fiber 40 having circular cross-section 42,
with five layered regions 44a, 44b, 44c, 44d, 44e, which comprise
alternatively at least the first polymeric composition and the
second polymeric composition. Optionally, a third, different
polymeric composition may be included in at least one of the
layers.
[0027] FIGS. 3A-3E illustrate perspective views of various
embodiments of multi-component fibers useful in the articles
according to the present disclosure. FIG. 3A illustrates a fiber 50
having a triangular cross-section 52. In the illustrated
embodiment, the first polymeric composition 54 exists in one
region, and the second polymeric composition 56 is positioned
adjacent the first polymeric composition 54.
[0028] FIG. 3B illustrates a ribbon-shaped embodiment 70 having a
generally rectangular cross-section and an undulating shape 72. In
the illustrated embodiment, a first layer 74 comprises the first
polymeric composition, while a second layer 76 comprises the second
polymeric composition.
[0029] FIG. 3C illustrates a coiled or crimped multi-component
fiber 80 useful for articles according to the present disclosure.
The distance between coils, 86, may be adjusted according to the
properties desired.
[0030] FIG. 3D illustrates a fiber 100 having a cylindrical shape,
and having a first annular component 102, a second annular
component 104, the latter component defining hollow core 106. The
first and second annular components typically comprise the first
polymeric composition and the second polymeric composition,
respectively. The hollow core 106 may optionally be partially or
fully filled with an additive (e.g., a curing agent or tackifier)
for one of the annular components 102, 104.
[0031] FIG. 3E illustrates a fiber with a lobed-structure 110, the
example shown having five lobes 112 with outer portions 114 and an
interior portion 116. The outer portions 114 and interior portion
116 typically comprise the first polymeric composition and the
second polymeric composition, respectively.
[0032] The aspect ratio of multi-component fibers described herein
may be, for example, at least 3:1, 4:1, 5:1, 10:1, 25:1, 50:1,
75:1, 100:1, 150:1, 200:1, 250:1, 500:1, 1000:1, or more; or in a
range from 2:1 to 1000:1. Larger aspect ratios (e.g., having aspect
ratios of 10:1 or more) may more easily allow the formation of a
network of multi-component fibers and may allow for more particles
to be adhered to the external surfaces of the fibers.
[0033] Multi-component fibers useful for the articles according to
the present disclosure include those having a length up to 60 mm,
in some embodiments, in a range from 2 mm to 60 mm, 3 mm to 40 mm,
2 mm to 30 mm, or 3 mm to 20 mm. Typically, the multi-component
fibers disclosed herein have a maximum cross-sectional dimension up
to 300 (in some embodiments, up to 250, 200, 150, 100, 90, 80, 70,
60, 50, 40, or 30) micrometers. For example, the fiber may have a
circular cross-section with an average diameter in a range from 1
micrometer to 300 micrometers, 1 micrometer to 100 micrometers, 10
micrometers to 50 micrometers, 10 micrometers to 30 micrometers, or
17 micrometers to 23 micrometers. In another example, the fiber may
have a rectangular cross-section with an average length (i.e.,
longer cross-sectional dimension) in a range from 1 micrometer to
300 micrometers, 1 micrometer to 100 micrometers, 10 micrometers to
50 micrometers, 10 micrometers to 30 micrometers, or 17 micrometers
to 23 micrometers.
[0034] In some embodiments, multi-component fibers useful for the
articles and methods according to the present disclosure are
non-fusing at a temperature of at least 110.degree. C. (in some
embodiments, at least 120.degree. C., 125.degree. C., 150.degree.
C., or at least 160.degree. C.). When multi-component fibers are
non-fusing at any of these temperatures, it will be understood that
they are also non-fusing below that temperature. In some
embodiments, multi-component fibers useful for the articles and
methods according to the present disclosure are non-fusing at a
maximum temperature of up to 200.degree. C. "Non-fusing" fibers can
autogenously bond (i.e., bond without the addition of pressure
between fibers) without significant loss of architecture, for
example, a core-sheath configuration. The spatial relationship
between the first polymeric composition, the second polymeric
composition, and optionally any other component of the fiber is
generally retained in non-fusing fibers. Typically multi-component
fibers (e.g., fibers with a core-sheath configuration) undergo so
much flow of the sheath composition during autogenous bonding that
the core-sheath structure is lost as the sheath composition becomes
concentrated at fiber junctions and the core composition is exposed
elsewhere. That is, typically multi-component fibers are fusing
fibers. This loss of structure typically results in the loss of the
functionality of the fiber provided by the sheath component. In
non-fusing fibers (e.g., core-sheath fibers) heat causes little or
no flow of the sheath composition so that the sheath functionality
is retained along the majority of the multi-component fibers.
[0035] To evaluate whether fibers are non-fusing at a particular
temperature, the following test method is used. The fibers are cut
to 6 mm lengths, separated, and formed into a flat tuft of
interlocking fibers. The larger cross-sectional dimension (e.g.,
the diameter for a circular cross-section) of twenty of the cut and
separated fibers is measured and the median recorded. The tufts of
the fibers are heated in a conventional vented convection oven for
5 minutes at the selected test temperature. Twenty individual
separate fibers are then selected and their larger cross-section
dimension (e.g., diameter) measured and the median recorded. The
fibers are designated as "non-fusing" if there is less than 20%
change in the measured dimension after the heating.
[0036] Typically, the dimensions of the multi-component fibers used
together in an article and/or method according to the present
disclosure, and components making up the fibers are generally about
the same, although use of fibers with even significant differences
in compositions and/or dimensions may also be useful. In some
applications, it may be desirable to use two or more different
groups of multi-component fibers (e.g., at least one different
polymer or resin, one or more additional polymers, different
average lengths, or otherwise distinguishable constructions), where
one group offers a certain advantage(s) in one aspect, and other
group a certain advantage(s) in another aspect.
[0037] Fibers described herein can generally be made using
techniques known in the art for making multi-component (e.g.,
bi-component) fibers. Such techniques include fiber spinning (see,
e.g., U.S. Pat. No. 4,406,850 (Hills), U.S. Pat. No. 5,458,972
(Hagen), U.S. Pat. No. 5,411,693 (Wust), U.S. Pat. No. 5,618,479
(Lijten), and U.S. Pat. No. 5,989,004 (Cook)).
[0038] Each component of the fibers, including the first polymeric
composition, second polymeric composition, and any additional
polymers, can be selected to provide desirable performance
characteristics.
[0039] In some embodiments, the first polymeric composition in the
multi-component fibers has a softening temperature up to
150.degree. C. (in some embodiments, up to 140.degree. C.,
130.degree. C., 120.degree. C., 110.degree. C., 100.degree. C.,
90.degree. C., 80.degree. C., or 70.degree. C. or in a range from
80.degree. C. to 150.degree. C.). The softening temperature of the
first polymeric composition is determined using a stress-controlled
rheometer (Model AR2000 manufactured by TA Instruments, New Castle,
Del.) according to the following procedure. A sample of the first
polymeric composition is placed between two 20 mm parallel plates
of the rheometer and pressed to a gap of 2 mm ensuring complete
coverage of the plates. A sinusoidal frequency of 1 Hz at 1% strain
is then applied over a temperature range of 80.degree. C. to
200.degree. C. The resistance force of the molten resin to the
sinusoidal strain is proportional to its modulus which is recorded
by a transducer and displayed in graphical format. Using
rheometeric software, the modulus is mathematically split into two
parts: one part that is in phase with the applied strain (elastic
modulus--solid-like behavior), and another part that is out of
phase with the applied strain (viscous modulus--liquid-like
behavior). The temperature at which the two moduli are identical
(cross-over temperature) is the softening temperature, as it
represents the temperature above which the resin began to behave
predominantly like a liquid.
[0040] For any of the embodiments of multi-component fibers
disclosed herein, the first polymeric composition may be a single
polymeric material, a blend of polymeric materials, or a blend of
at least one polymer and at least one other additive. The softening
temperature of the first polymeric composition, advantageously, may
be above the storage temperature of the multi-component fiber. The
desired softening temperature can be achieved by selecting an
appropriate single polymeric material or combining two or more
polymeric materials. For example, if a polymeric material softens
at too high of a temperature it can be decreased by adding a second
polymeric material with a lower softening temperature. Also, a
polymeric material may be combined with, for example, a plasticizer
to achieve the desired softening temperature.
[0041] Exemplary polymers that have or may be modified to have a
softening temperature up to 150.degree. C. (in some embodiments, up
to than 140.degree. C., 130.degree. C., 120.degree. C., 110.degree.
C., 100.degree. C., 90.degree. C., 80.degree. C., or 70.degree. C.
or in a range from 80.degree. C. to 150.degree. C.) include at
least one of (i.e., includes one or more of the following in any
combination) ethylene-vinyl alcohol copolymer (e.g., with softening
temperature of 156 to 191.degree. C., available from EVAL America,
Houston, Tex., under the trade designation "EVAL G176B"),
thermoplastic polyurethane (e.g., available from Huntsman, Houston,
Tex., under the trade designation "IROGRAN A80 P4699"),
polyoxymethylene (e.g., available from Ticona, Florence, Ky., under
the trade designation "CELCON FG40U01"), polypropylene (e.g.,
available from Total, Paris, France, under the trade designation
"5571"), polyolefins (e.g., available from ExxonMobil, Houston,
Tex., under the trade designation "EXACT 8230"), ethylene-vinyl
acetate copolymer (e.g., available from AT Plastics, Edmonton,
Alberta, Canada), polyester (e.g., available from Evonik,
Parsippany, N.J., under the trade designation "DYNAPOL" or from
EMS-Chemie AG, Reichenauerstrasse, Switzerland, under the trade
designation "GRILTEX"), polyamides (e.g., available from Arizona
Chemical, Jacksonville, Fla., under the trade designation "UNIREZ
2662" or from E. I. du Pont de Nemours, Wilmington, Del., under the
trade designation "ELVAMIDE 8660"), phenoxy (e.g., from Inchem,
Rock Hill S.C.), vinyls (e.g., polyvinyl chloride form Omnia
Plastica, Arsizio, Italy), or acrylics (e.g., from Arkema, Paris,
France, under the trade designation "LOTADEREX 8900"). In some
embodiments, the first polymeric composition comprises a partially
neutralized ethylene-methacrylic acid copolymer commercially
available, for example, from E. I. duPont de Nemours & Company,
under the trade designations "SURLYN 8660," "SURLYN 1702," "SURLYN
1857," and "SURLYN 9520"). In some embodiments, the first polymeric
composition comprises a mixture of a thermoplastic polyurethane
obtained from Huntsman under the trade designation "IROGRAN A80
P4699", a polyoxymethylene obtained from Ticona under the trade
designation "CELCON FG40U01", and a polyolefin obtained from
ExxonMobil Chemical under the trade designation "EXACT 8230". In
some embodiments, multi-component fibers useful for the articles
according to the present disclosure may comprise in a range from 5
to 85 (in some embodiments, 5 to 40, 40 to 70, or 60 to 70) percent
by weight of the first polymeric composition.
[0042] In some embodiments of articles and methods according to the
present disclosure, the first polymeric composition has an elastic
modulus of less than 3.times.10.sup.5 N/m.sup.2 at a frequency of
about 1 Hz at a temperature of at least 80.degree. C. In these
embodiments, typically the first polymeric composition is tacky at
the temperature of 80.degree. C. and above. In some embodiments,
the first polymeric composition has an elastic modulus of less than
3.times.10.sup.5 N/m.sup.2 at a frequency of about 1 Hz at a
temperature of at least 85.degree. C., 90.degree. C., 95.degree.
C., or 100.degree. C. For any of these embodiments, the modulus is
measured using the method described above for determining softening
temperature except the modulus is determined at the selected
temperature (e.g., 80.degree. C., 85.degree. C., 90.degree. C.,
95.degree. C., or 100.degree. C.).
[0043] In some embodiments of multi-component fibers useful for the
articles and methods disclosed herein, the second polymeric
composition has a melting point of at least 130.degree. C. (in some
embodiments, at least 140.degree. C. or 150.degree. C.; in some
embodiments, in a range from 130.degree. C. to 220.degree. C.,
150.degree. C. to 220.degree. C., or 160.degree. C. to 220.degree.
C.). Exemplary useful second polymeric compositions include at
least one of (i.e., includes one or more of the following in any
combination) an ethylene-vinyl alcohol copolymer (e.g., available
from EVAL America, under the trade designation "EVAL G176B"),
polyamide (e.g., available from E. I. du Pont de Nemours under the
trade designation "ELVAMIDE" or from BASF North America, Florham
Park, N.J., under the trade designation "ULTRAMID"),
polyoxymethylene (e.g., available from Ticona under the trade
designation "CELCON"), polypropylene (e.g., from Total), polyester
(e.g., available from Evonik under the trade designation "DYNAPOL"
or from EMS-Chemie AG under the trade designation "GRILTEX"),
polyurethane (e.g., available from Huntsman under the trade
designation "IROGRAN"), polysulfone, polyimide,
polyetheretherketone, or polycarbonate. As described above for the
first polymeric compositions, blends of polymers and/or other
components can be used to make the second polymeric compositions.
For example, a thermoplastic having a melting point of less than
130.degree. C. can be modified by adding a higher-melting
thermoplastic polymer. In some embodiments, the second polymeric
composition is present in a range from 5 to 40 percent by weight,
based on the total weight of the multi-component fiber. The melting
temperature is measured by differential scanning calorimetry (DSC).
In cases where the second polymeric composition includes more than
one polymer, there may be two melting points. In these cases, the
melting point of at least 130.degree. C. is the lowest melting
point in the second polymeric composition.
[0044] Optionally, fibers described herein may further comprise
other components (e.g., additives and/or coatings) to impart
desirable properties such as handling, processability, stability,
and dispersability. Exemplary additives and coating materials
include antioxidants, colorants (e.g., dyes and pigments), fillers
(e.g., carbon black, clays, and silica), and surface applied
materials (e.g., waxes, surfactants, polymeric dispersing agents,
talcs, erucamide, gums, and flow control agents) to improve
handling.
[0045] Surfactants can be used to improve the dispersibility or
handling of multi-component fibers described herein. Useful
surfactants (also known as emulsifiers) include anionic, cationic,
amphoteric, and nonionic surfactants. Useful anionic surfactants
include alkylarylether sulfates and sulfonates, alkylarylpolyether
sulfates and sulfonates (e.g., alkylarylpoly(ethylene oxide)
sulfates and sulfonates, preferably those having up to about 4
ethyleneoxy repeat units, including sodium alkylaryl polyether
sulfonates such as those known under the trade designation "TRITON
X200", available from Rohm and Haas, Philadelphia, Pa.), alkyl
sulfates and sulfonates (e.g., sodium lauryl sulfate, ammonium
lauryl sulfate, triethanolamine lauryl sulfate, and sodium
hexadecyl sulfate), alkylaryl sulfates and sulfonates (e.g., sodium
dodecylbenzene sulfate and sodium dodecylbenzene sulfonate), alkyl
ether sulfates and sulfonates (e.g., ammonium lauryl ether
sulfate), and alkylpolyether sulfate and sulfonates (e.g., alkyl
poly(ethylene oxide) sulfates and sulfonates, preferably those
having up to about 4 ethyleneoxy units). Useful nonionic
surfactants include ethoxylated oleoyl alcohol and polyoxyethylene
octylphenyl ether. Useful cationic surfactants include mixtures of
alkyl dimethylbenzyl ammonium chlorides, wherein the alkyl chain
has from 10 to 18 carbon atoms. Amphoteric surfactants are also
useful and include sulfobetaines, N-alkylaminopropionic acids, and
N-alkylbetaines. Surfactants may be added to the fibers disclosed
herein, for example, in an amount sufficient on average to make a
monolayer coating over the surfaces of the fibers to induce
spontaneous wetting. Useful amounts of surfactants may be in a
range, for example, from 0.05 to 3 percent by weight, based on the
total weight of the multi-component fiber.
[0046] Polymeric dispersing agents may also be used, for example,
to promote the dispersion of fibers described herein in a chosen
medium and at the desired application conditions (e.g., pH and
temperature). Exemplary polymeric dispersing agents include salts
(e.g., ammonium, sodium, lithium, and potassium) of polyacrylic
acids of greater than 5000 average molecular weight, carboxy
modified polyacrylamides (available, for example, under the trade
designation "CYANAMER A-370" from Cytec Industries, West Paterson,
N.J.), copolymers of acrylic acid and
dimethylaminoethylmethacrylate, polymeric quaternary amines (e.g.,
a quaternized polyvinyl-pyrollidone copolymer (available, for
example, under the trade designation "GAFQUAT 755" from ISP Corp.,
Wayne, N.J.) and a quaternized amine substituted cellulosic
(available, for example, under the trade designation "JR-400" from
Dow Chemical Company, Midland, Mich.), cellulosics,
carboxy-modified cellulosics (e.g., sodium carboxy methycellulose
(available, for example, under the trade designation ""NATROSOL CMC
Type 7L" from Hercules, Wilmington, Del.), and polyvinyl alcohols.
Polymeric dispersing agents may be added to the fibers disclosed
herein, for example, in an amount sufficient on average to make a
monolayer coating over the surfaces of the fibers to induce
spontaneous wetting. Useful amounts of polymeric dispersing agents
may be in a range, for example, from 0.05 to 5 percent by weight,
based on the total weight of the fiber.
[0047] Examples of antioxidants that may be useful additives in the
multi-component fibers include hindered phenols (available, for
example, under the trade designation "IRGANOX" from Ciba Specialty
Chemical, Basel, Switzerland). Typically, antioxidants are used in
a range from 0.1 to 1.5 percent by weight, based on the total
weight of the fiber, to retain useful properties during extrusion
and through the life of the article.
[0048] In some embodiments of the fibers useful for practicing the
present disclosure, the fibers may be crosslinked, for example,
through radiation or chemical means. Chemical crosslinking can be
carried out, for example, by incorporation of thermal free radical
initiators, photoinitiators, or ionic crosslinkers. When exposed to
a suitable wavelength of light, for example, a photoinitiator can
generate free radicals that cause crosslinking of polymer chains.
With radiation crosslinking, initiators and other chemical
crosslinking agents may not be necessary. Suitable types of
radiation include any radiation that can cause crosslinking of
polymer chains such as actinic and particle radiation (e.g.,
ultraviolet light, X-rays, gamma radiation, ion beam, electronic
beam, or other high-energy electromagnetic radiation). Crosslinking
may be carried out to a level at which, for example, an increase in
modulus of the first polymeric composition is observed.
[0049] Depending on the application, particles useful for
practicing the present disclosure have sizes, for example, in a
range from 100 micrometers to 3000 micrometers (i.e., about 140
mesh to about 5 mesh (ANSI)) (in some embodiments, in a range from
1000 micrometers to 3000 micrometers, 1000 micrometers to 2000
micrometers, 1000 micrometers to 1700 micrometers (i.e., about 18
mesh to about 12 mesh), 850 micrometers to 1700 micrometers (i.e.,
about 20 mesh to about 12 mesh), 850 micrometers to 1200
micrometers (i.e., about 20 mesh to about 16 mesh), 600 micrometers
to 1200 micrometers (i.e., about 30 mesh to about 16 mesh), 425
micrometers to 850 micrometers (i.e., about 40 to about 20 mesh),
or 300 micrometers to 600 micrometers (i.e., about 50 mesh to about
30 mesh). In some embodiments, the particles have a particle size
in a range from 500 nanometers to 50 micrometers. In some
embodiments, the particles have a particle size up to 25
micrometers, which may be in a range from 500 nanometers to 25
micrometers.
[0050] The ratio of particles to multi-component fibers useful for
articles and methods of the present disclosure depends, for
example, on the application, the crossover point density in the
fibers, the shape of the particles, and the particle size
distribution. In some embodiments, the maximum amount of particles
useful in the articles disclosed herein is the closest packing
density of the particles. Useful weight ratios for a given particle
and a given application are described below. In some embodiments,
mixtures and articles comprising only the particles and the
multi-component particles are useful, while in other embodiments,
other suitable components may be added to the article or mixture
depending on the application as described below.
[0051] The method of making an article according to the present
disclosure includes providing a mixture of particles and
multi-component fibers. Mixing can be carried out by techniques
involving mechanical and/or electrostatic mixing of particles.
Solvents or water can optionally be included to assist in uniformly
mixing the particles and the fibers. In some embodiments, however,
the mixing of the particles and the multi-component fibers is a
solventless process, which is advantageous because no heating is
necessary to evaporate residual water or solvents, which can
eliminate process steps and reduce cost. Mixing can be carried out,
for example, via convective mixing, diffusive mixing, and shear
mixing mechanisms. For example, mixing the particles with the
multi-component fibers can be carried out using conventional
tumbling mixers (e.g., V-blender, double cone, or rotating cube);
convective mixers (e.g., ribbon blender, nautamixer); fluidized bed
mixers; or high-shear mixers. In some embodiments, the particles
and multi-component fibers are tumbled together in a suitable
container. In some embodiments, before the multi-component fibers
and particles are mixed using such processes (e.g., tumbling), the
multi-component fibers are separated to increase the exposed
surface area of the fibers. The multi-component fibers may be in
bundles when they are formed, and suitable methods such as
subjecting the fibers to a grinder may be useful for separating the
fibers and exposing their surfaces. In other embodiments, the
multi-component fibers may first be formed into a web, for example,
by air-laying and thermally bonding, and the resulting web may be
shaken together with the particles. In these embodiments,
air-laying the fibers can separate any bundles of fibers and
increase their exposed surface area.
[0052] The method according to the present disclosure includes
heating the mixture of the particles and the multi-component fibers
to a temperature at which the multi-component fibers are non-fusing
and at which the first polymeric composition has an elastic modulus
of less than 3.times.10.sup.5 N/m.sup.2 when measured at a
frequency of one hertz. The temperature is above the softening
temperature of the first polymeric composition and includes any of
the ranges of softening temperatures for the first polymeric
composition described above. At the temperature, the first
polymeric composition will become tacky, and the fibers can adhere
to each other and to the particles to form a web. The particles are
typically distributed throughout the thickness of the web. In some
embodiments, the mixture is placed in a mold before it is heated.
Pressure may be applied to the mold, if desired, to consolidate the
pack of particles and multi-component fibers. The mold can have any
shape depending on the desired application.
[0053] In some embodiments, the particles are activated carbon
particles. As used herein, "activated carbon" refers to highly
porous carbon having a random or amorphous structure. Such
particles are also known as charcoal particles and activated
charcoal particles. Useful activated carbon particles may have an
average particle size in a range from 500 nanometers to 10
millimeters (mm) (e.g., from 1 micrometer to 1 mm, 10 micrometers
to 500 micrometers, 10 micrometers mm to 50 micrometers, or 500
nanometers to 50 micrometers). Typically the activated carbon
particles have pores that are large enough to take in, for example,
impurities when used in a filtration application. In some
embodiments, the interior pores have a median pore size in a range
from 0.3 nanometers (nm) to 10 nm (e.g., 0.3 nm to 3 nm, 2 nm to 7
nm, 4 nm to 7 nm, 8 nm to 10 nm, or 4 nm to 10 nm). The pore sizes
may be unimodal, or the activated carbon particles may have a
bimodal porous structure wherein the pores have two different
median sizes selected from any of the listed ranges.
[0054] Activated carbon products useful for practicing the present
disclosure include granules and pellets of activated carbon
available, for example, from Calgon Carbon, Inc. (Pittsburgh, Pa.),
MeadWestvaco Corporation (Charleston, S.C.), EMD Chemicals
(Gibbstown, N.J.), and Kuraray Chemical Co., Ltd. (Osaka, Japan).
Activated carbon from any source can be used, including that
derived from bituminous coal or other forms of coal, or from pitch,
coconut shells, corn husks, polyacrylonitrile (PAN) polymers,
charred cellulosic fibers or materials, and wood. Activated carbon
particles can, for example, be formed directly by activation of
coal or other materials, or by grinding carbonaceous material to a
fine powder, agglomerating it with pitch or other adhesives, and
then converting the agglomerate to activated carbon.
[0055] In some embodiments, activated carbon useful for practicing
the present disclosure is provided with functional groups to modify
its surface properties. For example, during the activation stage,
the carbon can be exposed to nitric acid to add carboxylic acid
groups, hydrogen chloride to add chlorine groups, to oxygen or
water vapor to add oxygen or hydroxyl groups, to ammonia to add
amine groups, and to hydrogen to add hydrogen atoms. Methods of
surface modification of activated carbon to produce acidic, basic,
and neutral functional groups are described in Shen et al.,
"Surface Chemical Functional Groups Modification of Porous Carbon",
Recent Patents on Chemical Engineering, 2008, 1, 27-40.
Alternatively, a compound such as a non-gaseous molecule may be
added to the carbon prior to activating it or prior to a
post-treatment step, wherein the compound reacts at elevated
temperature to add functional groups to the activated carbon. Such
a process is described, for example, in U.S. Pat. No. 5,521,008,
(Lieberman et al.).
[0056] The weight ratio of the multi-component fibers to activated
carbon particles may be, for example, in a range from 10:1 to 1:1,
in some embodiments, in a range from 8:1 to 1:1, 8:1 to 2:1, or 8:1
to 4:1.
[0057] Articles according to and/or made according to the present
disclosure in which the particles are activated carbon particles
may be useful for filtration applications. Known as an adsorbent,
activated carbon can take up and hold on its surface dissolved
organic contaminants (e.g., pesticidal residues and organic
vapors), and it can also remove chlorine from, for example,
drinking water. Other particles may be useful in combination with
the activated carbon and the multi-component fibers for filtration
applications. For example, metal ion exchange zeolite sorbents, ion
exchange resins, antimicrobial agents, activated alumina, and
particulate filter media may be useful additives. In some
embodiments, the article disclosed herein may be useful in
combination with a sand filter or other particulate filter. In some
embodiments, the article and mixture according to the present
disclosure further comprises sand.
[0058] Articles including carbon particles can be useful, for
example, for gravity filtration applications, filters for
refrigerators that dispense chilled drinking water and ice, and
other water filtration applications. Using the methods disclosed
herein, an activated carbon filter can be assembled without the use
of sophisticated equipment because of the adhesive nature of the
fibers at relative low temperatures (e.g., 80.degree. C.).
Accordingly, articles according to and/or made according to the
present disclosure may be useful for water filtration in rural
areas of developing countries.
[0059] An article according to the present disclosure can be formed
into any desirable shape using a mold, for example. In some
embodiments, filtration articles disclosed herein may be formed as
cylinders or discs. The cylinders or discs may be provided with
grooves or dimples to increase the surface area of the resulting
filter. In some embodiments, the article according to the present
disclosure may be in the form of a hollow cylinder, which may be
tube-shaped such that there is a core and a wall thickness. In some
typical water filtration applications, water may be directed to
flow radially from the outside diameter (OD) surface of the tube to
the inside diameter (ID) and then out one end of the core.
Optionally, pressure may be used to consolidate the mixture in the
mold before or during heating. Heating may be carried out in a
conventional oven or using microwave, infrared, or radio frequency
heating. The article may be free-standing when it is released from
the mold. In other embodiments, the mixture is introduced into a
casing before the heating, wherein the casing is a pipe or
cylinder, and wherein at least a portion of the mixture becomes
adhered to the casing.
[0060] Photomicrographs of exemplary articles according to the
present disclosure in which activated carbon 202 is adhered to the
surfaces of multi-component fibers 204 are shown in FIGS. 4A and
4B.
[0061] In some embodiments, the particles are abrasive particles,
and the articles according to the present disclosure are abrasive
articles. These articles can be used for abrasive cutting or
shaping, polishing, or cleaning of metals, wood, plastics, and
other materials. Additionally, abrasive particles on the
multi-component fiber surfaces can provide friction (e.g., for
anti-slip applications).
[0062] Abrasives particles useful for practicing the present
disclosure can be granules of regular or nonregular shape, of
virtually any size, and selected from a broad variety of classes of
natural or synthetic, abrasive, mineral particulate, such as
silicon carbide, aluminum oxide (e.g., ceramic aluminum oxide,
heat-treated aluminum oxide, and white-fused aluminum oxide), cubic
boron nitride, ceramic beads or grains such as abrasive materials
available from 3M Company, St. Paul, Minn., under the trade
designation "CUBITRON", alumina zirconia, diamond, ceria (that is,
cerium oxide), garnet, flint, silica, pumice, calcium carbonate,
plastic abrasive grains (e.g., made of polyester,
polyvinylchloride, methacrylates, polycarbonates, melamine, and
polystyrene), crushed plant materials (e.g., shells such as walnut
shells and pits such as apricot, peach, and avocado pits), and
mixtures of one or more of these materials. The ultimate use of the
abrasive article will determine what abrasive particles are most
suitable. In some embodiments, the abrasive particles comprise at
least one of ceria, silicon carbide, and cubic boron nitride
particles. In some embodiments, the abrasive particles comprise
ceria particles (that is, cerium oxide particles).
[0063] Conventional methods of creating an abrasive article
typically rely on first coating a suitable substrate, which may be
a prebonded fiber web, with a durable binder resin (that is, make
coat precursor) and abrasive particles or other materials, and
curing the abrasive article. The particles may be applied to the
fibers in a slurry with a durable binder resin. Typically, a size
coat is applied over the make coat precursor and the particles to
achieve durability, toughness, and functionality. Such a process
typically requires high performance resin systems that contain
solvents and other hazardous chemicals that necessitate additional
careful monitoring to ensure adequate cure with minimization of
residual ingredients as well as sophisticated pollution control
schemes to control harmful solvent emissions.
[0064] The multi-component fibers disclosed herein allow
simplification to the overall abrasive- or particle-holding binder
systems by elimination of solvent-coating techniques and
elimination even of the need for additional bonding agents between
the particles and the multi-component fibers. Typically, in the
abrasive articles disclosed herein, the particles are directly
attached to the first polymeric composition on the external surface
of the fibers without the use of a make coat or other binder. In
some embodiments, articles according to the present disclosure do
not include a size coat. In other embodiments, it may be useful to
provide a size coat using conventional techniques.
[0065] In some embodiments of the method of making at article
disclosed herein, wherein the article is an abrasive article, the
multi-component fibers are made into a web, for example, by
air-laying and thermally bonding at a temperature at which the
multi-component fibers are non-fusing and at which the first
polymeric composition has an elastic modulus of less than
3.times.10.sup.5 N/m.sup.2 when measured at a frequency of one
hertz. The resulting web may be shaken together with the abrasive
particles and the mixture heated to a temperature at which the
multi-component fibers are non-fusing and at which the first
polymeric composition has an elastic modulus of less than
3.times.10.sup.5 N/m.sup.2 when measured at a frequency of one
hertz. At this temperature, the first polymeric composition will be
tacky, and the abrasive particles will adhere to the fibers. Using
this method, the abrasive particles will be distributed throughout
the thickness of the web.
[0066] The weight ratio of the abrasive particles to the
multi-component fibers may be, for example, in a range from 10:1 to
1:1, in some embodiments, in a range from 8:1 to 1:1 or from 5:1 to
1:5, depending on the identity of the abrasive particle.
[0067] The abrasive articles according to and/or made according to
some embodiments of the present disclosure have good polishing
capabilities. However, the construction of the articles disclosed
herein provides advantages over typical commercial processes. For
example, in typical commercial processes, ceria is applied as a
slurry. Used ceria slurries may either be recovered for reuse or
disposed of, both of which can result in higher cost associated
with equipment and material loss. In contrast, the multi-component
fibers described herein can adhere a large quantity of ceria
particles without significant material loss. Also, in use, abrasive
articles which have abrasive particles coated only on one surface,
which is typical for conventional abrasives, may lose their
abrasive capability more quickly than when abrasive particles are
located throughout the web of multi-component fibers as in the
present applications. Furthermore, even though they have a
relatively simple construction, which may include only
multi-component fibers and particles (e.g., with no size coat), the
articles disclosed herein have remarkably good abrasive
performance.
[0068] It should be understood that an abrasive article according
to the present disclosure must be usable as an abrasive article.
Accordingly, it should be understood that the abrasive articles
disclosed herein are not located in or bonded to a fracture in a
subterranean formation such as a hydrocarbon (e.g., oil or gas)
bearing geological formation. Similarly, in the method disclosed
herein, heating the mixture to a temperature at which the
multi-component fibers are non-fusing and at which the first
polymeric composition has an elastic modulus of less than
3.times.10.sup.5 N/m.sup.2 at a temperature of at least 80.degree.
C. measured at a frequency of one hertz does not include injecting
the mixture of microspheres and multi-component fibers into a
subterranean formation such as a hydrocarbon (e.g., oil or gas)
bearing geological formation or into a fracture in such a
formation.
[0069] In some embodiments of the articles and methods of the
present disclosure, the particles are superabsorbent polymer (SAP)
particles. Examples of SAP materials include the alkali metal and
ammonium salts of poly(acrylic acid) and poly(methacrylic acid),
poly(acrylamides), poly(vinyl ethers), maleic anhydride copolymers
with vinyl ethers and alpha-olefins, poly(vinyl pyrolidone),
poly(vinyl morpholinone), poly(vinyl alcohol), and mixtures and
copolymers thereof. SAP materials are widely commercially available
(e.g., from Evonik Industries, Krefeld, Germany, under the trade
designation "FAVOR" or from Stockhausen Corporation of Greensboro,
N.C., under the trade designation "FAVOR SXM 880"). The SAP
particles may be in any of a wide variety of geometric forms
including fibers, flakes, rods, spheres, or needles.
[0070] In some embodiments, the article of the present disclosure
may be an absorbent component in an absorbent article comprising a
liquid permeable topsheet, a liquid impermeable backsheet, with the
article of the present disclosure disposed between the topsheet and
the backsheet. Such absorbent articles typically include sanitary
napkins, diapers, and other incontinence articles.
[0071] Other fibers can be used to impart certain properties to the
final article. For example, in filtration applications cellulose or
glass fibers can be used in the article to allow the filter to wet
out quickly. In abrasive articles, single-component fibers of at
least one of nylon, rayon, polyester, or cotton may be useful.
Some Embodiments of the Disclosure
[0072] In a first embodiment, the present disclosure provides an
article comprising:
[0073] multi-component fibers having external surfaces and
comprising at least a first polymeric composition and a second
polymeric composition, wherein at least a portion of the external
surfaces of the multi-component fibers comprises the first
polymeric composition, and wherein the multi-component fibers are
adhered together and are non-fusing at a temperature of at least
110.degree. C.; and
[0074] particles adhered at least to the first polymeric
composition on the external surfaces of at least some of the
multi-component fibers along their lengths, wherein the particles
comprise at least one of activated carbon and superabsorbent
polymer particles.
[0075] In a second embodiment, the present disclosure provides an
article comprising:
[0076] a web of multi-component fibers having external surfaces and
comprising at least a first polymeric composition and second
polymeric composition, wherein at least a portion of the external
surfaces of the multi-component fibers comprises the first
polymeric composition, and wherein the multi-component fibers are
adhered together and are non-fusing at a temperature of at least
110.degree. C.; and
[0077] particles directly attached to the first polymeric
composition on the external surfaces of at least some of the
multi-component fibers along their lengths, wherein the particles
comprise at least one of activated carbon, superabsorbent
particles, and abrasive particles, and wherein the particles are
distributed throughout the thickness of the web.
[0078] In a third embodiment, the present disclosure provides the
article of the second embodiment, wherein the article is an
abrasive article, wherein the particles are abrasive particles, and
wherein the abrasive article does not include a size coat.
[0079] In a fourth embodiment, the present disclosure provides the
article of the second embodiment, wherein the article is an
abrasive article, and wherein the particles are abrasive particles
comprising cerium oxide.
[0080] In a fifth embodiment, the present disclosure provides the
article of the first or second embodiment, wherein the article
comprises activated carbon, and may be, for example, a filter.
[0081] In a sixth embodiment, the present disclosure provides the
article of any one of the first to fifth embodiments, wherein the
first polymeric composition has a softening temperature of up to
150.degree. C., wherein the second polymeric composition has a
melting point of at least 130.degree. C., and wherein the
difference between the softening temperature of the first polymeric
composition and the melting point of the second polymeric
composition is at least 10.degree. C.
[0082] In a seventh embodiment, the present disclosure provides the
article of any one of the first to sixth embodiments, wherein the
first polymeric composition has an elastic modulus of less than
3.times.10.sup.5 N/m.sup.2 at a temperature of at least 80.degree.
C. measured at a frequency of one hertz.
[0083] In an eighth embodiment, the present disclosure provides the
article of any one of the first to seventh embodiments, wherein the
multi-component fibers are in a range from 10 micrometers to 300
micrometers in diameter.
[0084] In a ninth embodiment, the present disclosure provides the
article of any one of the first to eighth embodiments, wherein the
first polymeric composition is at least one of ethylene-vinyl
alcohol copolymer, at least partially neutralized
ethylene-methacrylic acid or ethylene-acrylic acid copolymer,
polyurethane, polyoxymethylene, polypropylene, polyolefin,
ethylene-vinyl acetate copolymer, polyester, polyamide, phenoxy,
vinyl, or acrylic.
[0085] In a tenth embodiment, the present disclosure provides the
article of any one of the first to ninth embodiments, wherein the
second polymeric composition is at least one of an ethylene-vinyl
alcohol copolymer, polyamide, polyoxymethylene, polypropylene,
polyester, polyurethane, polysulfone, polyimide,
polyetheretherketone, or polycarbonate.
[0086] In an eleventh embodiment, the present disclosure provides
the article of any one of the first to tenth embodiments, wherein
the multi-component fibers are non-fusing at a temperature of at
least 150.degree. C.
[0087] In a twelfth embodiment, the present disclosure provides the
article of any one of the first to eleventh embodiments, wherein
the multi-component fibers are in a range from 3 millimeters to 60
millimeters in length.
[0088] In a thirteenth embodiment, the present disclosure provides
the article of any one of the first to twelfth embodiments, further
comprising other, different fibers.
[0089] In a fourteenth embodiment, the present disclosure provides
the article of any one of the first to thirteenth embodiments,
wherein the particles have an average size in a range from 500
nanometers to 50 micrometers.
[0090] In a fifteenth embodiment, the present disclosure provides
the article of any one of the first to fourteenth embodiments,
wherein the particles have an average size up to twenty-five
micrometers.
[0091] In a sixteenth embodiment, the present disclosure provides a
method of making an article, the method comprising:
[0092] providing a mixture of particles and multi-component fibers,
the multi-component fibers comprising at least a first polymeric
composition and a second polymeric composition, and the particles
comprising at least one of activated carbon, superabsorbent polymer
particles, and abrasive particles; and
[0093] heating the mixture to a temperature at which the
multi-component fibers are non-fusing and at which the first
polymeric composition has an elastic modulus of less than
3.times.10.sup.5 N/m.sup.2 when measured at a frequency of one
hertz, wherein at least a portion of the mixture becomes adhered
together to form a web, and wherein the particles are dispersed
throughout the thickness of the web.
[0094] In a seventeenth embodiment, the present disclosure provides
the method of the sixteenth embodiment, wherein the temperature is
at least 80.degree. C.
[0095] In an eighteenth embodiment, the present disclosure provides
the method of the sixteenth or seventeenth embodiment, wherein the
first polymeric composition has a softening temperature of up to
150.degree. C., wherein the second polymeric composition has a
melting point of at least 130.degree. C., and wherein the
difference between the softening temperature of the first polymeric
composition and the melting point of the second polymeric
composition is at least 10.degree. C.
[0096] In a nineteenth embodiment, the present disclosure provides
the method of any one of the sixteenth to eighteenth embodiments,
wherein the multi-component fibers are in a range from 3
millimeters to 60 millimeters in length.
[0097] In a twentieth embodiment, the present disclosure provides
the method of any one of the sixteenth to nineteenth embodiments,
wherein the multi-component fibers are in a range from 10 to 300
micrometers in diameter.
[0098] In a twenty-first embodiment, the present disclosure
provides the method of any one of the sixteenth to twentieth
embodiments, wherein the article is a filter comprising activated
carbon.
[0099] In a twenty-second embodiment, the present disclosure
provides the method of any one of the sixteenth to twentieth
embodiments, wherein the article is an abrasive article.
[0100] In a twenty-third embodiment, the present disclosure
provides the method of any one of the sixteenth to twenty-second
embodiments, wherein the mixture further comprises other, different
fibers.
[0101] In a twenty-fourth embodiment, the present disclosure
provides the method of any one of the sixteenth to twenty-third
embodiments, wherein the mixture is introduced into a mold before
the heating.
[0102] In order that this disclosure can be more fully understood,
the following examples are set forth. The particular materials and
amounts thereof recited in these examples, as well as other
conditions and details, should not be construed to unduly limit
this disclosure.
EXAMPLES
[0103] In these examples, all percentages, proportions and ratios
are by weight unless otherwise indicated. These abbreviations are
used in the following examples: g=gram, min=minutes, in =inch,
m=meter, cm=centimeter, mm=millimeter, .mu.m=micrometer,
ml=milliliter, psi=pounds per square inch, and Pa=Pascal.
Materials
[0104] The following materials were used in the preparation of
Comparative Example A, Illustrative Example 1, and Examples
1-4:
TABLE-US-00001 TRADE DESIGNATION DESCRIPTION SUPPLIER "ULTRAMID
B24" Polyamide 6 BASF North America, Florham Park, NJ "AMPLIFY IO
3702" Ethylene acrylic acid Dow Chemical, ionomer Midland, MI
"DARCO-G60" Charcoal EMD Chemicals, Gibbstown, New Jersey "UNICER
166" Cerium oxide Universal Photonics, powder Hicksville, NY
Test Methods
Glass Polishing:
[0105] A glass polishing test was performed using a 12 in (30.48
cm) overhead swing arm lapping machine (model "6Y-1" commercially
available from Strasbaugh, San Luis Obispo, Calif.). The lapping
machine comprised a movable polishing head having a diameter of
about 6 in (15.24 cm), and a lower platen, onto which an abrasive
article was mounted. A glass substrate having a thickness of about
0.125 in (0.31 cm) (part number "06120256" obtained from
SwiftGlass, Elmira Heights, N.Y.) was mounted on the polishing
head. The polishing head was run in counter clock-wise direction at
58 rpm with an oscillating sweep across the surface (8 inch (20.32
cm) sweep) and a down force of about 1.5 psi (1.0.times.10.sup.4
Pa). The lower platen was run at 74 rpm in counter clock-wise
direction. A polishing slurry comprising 5% wt of "UNICER 166"
cerium oxide in deionized water was deposited on the center of the
lower platen at flow rate of about 15 ml/min. The polishing slurry
had a pH of about 4. Glass substrates were weighed before and after
15 minutes of polishing (1 cycle). 12 samples of each abrasive
article were submitted to a polishing cycle and reduction in
thickness indicated by average cut rate (expressed in angstrom
(.ANG.) per minute). The thickness was calculated according to the
following equation:
Thickness=Weight of glass substrate/(substrate
density.times.substrate area) (1)
Comparative Example a and Example 1
[0106] Articles comprising multi-component fibers and particle
composites were prepared as described below.
[0107] Multi-component fibers were prepared as generally described
in Example 1 of U.S. Pat. No. 4,406,850 (Hills), incorporated
herein by reference, except (a) the die was heated to the
temperature listed in Table 1, below; (b) the extrusion die had
sixteen orifices laid out as two rows of eight holes, wherein the
distance between holes was 12.7 mm (0.50 in) with square pitch, and
the die had a transverse length of 152.4 mm (6.0 inches); (c) the
hole diameter was 1.02 mm (0.040 in) and the length to diameter
ratio was 4.0; (d) the relative extrusion rates in grams per hole
per minute of the two streams are reported in Table 1; (e) the
fibers were conveyed downwards a distance reported in Table 1 and
air quenched by compressed air and wound on a core; and (f) the
spinning speed was adjusted by a pull roll to rates reported in
Table 1.
TABLE-US-00002 TABLE 1 Core Sheath Rate, Rate, grams grams Pull
Roll Multi- per per Die Speed, Distance to component hole per hole
per Temperature, Meters/ Quench, Fiber minute minute .degree. C.
minute centimeters Fiber 1 0.25 0.24 220 950 36
[0108] The core material (second polymeric composition) for the
multi-component fibers was "ULTRAMID B24" polyamide 6. The sheath
material (first polymeric composition) was "AMPLIFY IO 3702"
ethylene-acrylic acid ionomer. The multi-component fibers had a
fiber density of about 1.02 g/mL, an average diameter of about 20
.mu.m and were chopped to a length of about 6 mm.
[0109] The softening temperature of "AMPLIFY IO 3702" ethylene
acrylic acid ionomer was found to be 110.degree. C. when evaluated
using the method described in the Detailed Description (page 6,
line 27 to page 7, line 2). That is, the crossover temperature was
110.degree. C. Also using this method except using a frequency of
1.59 Hz, the elastic modulus was found to be 8.6.times.10.sup.4
N/m.sup.2 at 100.degree. C., 6.1.times.10.sup.4N/m.sup.2 at
110.degree. C., 4.3.times.10.sup.4 N/m.sup.2 at 120.degree. C.,
2.8.times.10.sup.4 N/m.sup.2 at 130.degree. C., 1.9.times.10.sup.4
N/m.sup.2 at 140.degree. C., 1.2.times.10.sup.4N/m.sup.2 at
150.degree. C., and 7.6.times.10.sup.3 N/m.sup.2 at 160.degree. C.
The melting point of "AMPLIFY IO 3702" ethylene acrylic acid
ionomer is reported to be 92.2.degree. C. by Dow Chemical in a data
sheet dated 2011. The melting point of "ULTRAMID B24" polyamide 6
is reported to be 220.degree. C. by BASF in a product data sheet
dated September 2008. The grade of the "ULTRAMID B24" polyamide 6
did not contain titanium dioxide. A fiber having the same sheath
except obtained under trade designation "SURYLYN 1702" from E. I.
duPont de Nemours & Company, Wilmington, Del., which is
reported in a product data sheet dated 2010 to have a melting point
of 93.degree. C. and the same melt flow rate as "AMPLIFY IO 3702"
ethylene acrylic acid ionomer, and a core made from "ZYTEL RESIN
101NC010" from E.I. DuPont de Nemours & Company was evaluated
using the method described on page 6, lines 4 to 11. The fiber
diameter changed less than 10% when the evaluation was carried out
at 150.degree. C. The fibers were found to be non-fusing. See
Example 5 of U.S. Pat. App. Pub. No. 2010/0272994 (Carlson et
al.).
[0110] Multi-component fibers were prepared by opening up fiber
bundles using a Mr. Coffee grinder (model "IDS 55" obtained from
Mr. Coffee, Boca Raton, Fla.) for 15-30 seconds until the fiber was
lofty with no visible bundles. About 5 g of the multi-component
fibers and 1 g of "DARCO-G60" charcoal were added to a glass jar.
The glass jar was closed and tumbled gently at room temperature on
a 5-Rollver Oven (obtained from OFITE, Houston, Tex.) at a setting
of 30% for 30 minutes. The fiber charcoal mixture was then removed
from the glass jar and a minimal amount of loose carbon (about 0.05
g) was observed left in the glass jar.
[0111] About 6 g of fiber-charcoal mixtures were placed into first
and second hollow metal tubes, each measuring 2 in (5 cm) in
diameter and 12 in (30.5 cm) in length. The first tube was then
heated to 150.degree. C. for 60 minutes in an oven obtained from H
& C Thermal Systems, Columbia, Md., under the trade designation
"THERMOLYNE OVEN SERIES 9000". The fiber-charcoal mixture in the
first tube formed a fiber-charcoal composite, and this sample is
hereinafter referred to as Example 1. The fiber-charcoal mixture in
the second tube (not heated) did not form a composite and is
hereinafter referred to as Comparative Example A. Upon cooling to
room temperature, 50 g of water was run through each tube and the
throughput water was collected in a beaker. The presence of
charcoal particles in the collected water was visually determined.
No charcoal and/or fiber particles were detected in the water
collected from the first tube. Charcoal and fiber particles were
clearly visible in the water collected from the second tube even
after rinsing.
Illustrative Example 1
[0112] Multi-component fibers were prepared as described in Example
1. The multi-component fibers were subsequently air laid to form a
fiber web having a density of about 400 g/m.sup.2. The web was
thermally bonded using a 5.5 m long drying oven further comprising
a conveyor belt. The temperature in the drying oven was set to
120.degree. C. The speed of the conveyor belt was of about 1 m/min.
At the end of the drying oven, a press roller was used to set the
final thickness of the web to 0.75 inch (1.9 cm).
Example 2
[0113] A fiber web was prepared as described in Illustrative
Example 1. "UNICER 166" cerium oxide particles having a particle
size of about 0.5 .mu.m were then dropped onto the fiber web at a
weight ratio of about 4:1 cerium oxide: multi-component fibers. The
particle-loaded web comprising a first surface and a second
surface, opposite the first surface, was hand shaken to allow the
particles to penetrate the web. One layer of a 2-mil (50 .mu.m)
thick PTFE film-lined (commercially available from Plastics
International, Eden Prairie, Minn.) was disposed on each surface of
the particle-loaded web. A 2 mm thick aluminum perforated plate was
placed adjacent the PTFE film on the first surface. The perforated
plate comprised several 3 mm diameter perforations. The
perforations were spaced 5 mm apart (center to center) in a given
line. The lines were staggered and spaced 4 mm apart (center to
center). The particle-loaded web was then placed under a hot press
at a temperature of 80.degree. C., under a pressure of about 2000
psi (13.8 MPa) for 20 minutes, forming a fiber-particle composite.
The aluminum plate was removed from the first surface to form an
abrasive article comprising a patterned protruded surface, as shown
in FIG. 5.
[0114] Abrasive articles of Illustrative Example 1 and Example 2
were used for glass polishing, as described in the test method
above. Results are reported in Table 2, below.
TABLE-US-00003 TABLE 2 Samples Average cut rate (.ANG./minute)
Illustrative Example 1 1000 Example 2 1200
[0115] Various modifications and alterations to this disclosure
will become apparent to those skilled in the art without departing
from the scope and spirit of this disclosure. It should be
understood that this disclosure is not intended to be unduly
limited by the illustrative embodiments and examples set forth
herein and that such examples and embodiments are presented by way
of example only with the scope of the disclosure intended to be
limited only by the claims set forth herein as follows.
* * * * *