U.S. patent application number 16/626244 was filed with the patent office on 2020-05-21 for nonwoven article and method of making the same.
The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Megan A. Creighton, Joel A. Getschel, Emily S. Goenner, Raymond P. Johnston, Morgan A. Priolo.
Application Number | 20200157734 16/626244 |
Document ID | / |
Family ID | 63080211 |
Filed Date | 2020-05-21 |
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United States Patent
Application |
20200157734 |
Kind Code |
A1 |
Creighton; Megan A. ; et
al. |
May 21, 2020 |
NONWOVEN ARTICLE AND METHOD OF MAKING THE SAME
Abstract
A method comprises exposing a particle coating disposed on a
nonwoven fiber web comprising thermally-softenable fibers to pulsed
electromagnetic radiation having at least one wavelength in the
range of 200 nm to 1000 nm. The particle coating comprises distinct
particles that are not chemically bonded to each other, and are not
retained in a binder material other than the thermally-softenable
fibers. Also disclosed are nonwoven articles comprising a
thermally-softenable nonwoven fiber web having a particle coating
disposed thereon. The particle coating comprises distinct particles
that are not chemically bonded to each other and are not retained
in a binder material other than the thermally-softenable nonwoven
fiber web. The particle coating is at least 60 percent retained
after a one minute immersion in isopropanol at 22.degree. C.
Inventors: |
Creighton; Megan A.;
(Somerville, MA) ; Goenner; Emily S.; (Shoreview,
MN) ; Johnston; Raymond P.; (Lake Elmo, MN) ;
Priolo; Morgan A.; (Woodbury, MN) ; Getschel; Joel
A.; (Osceola, WI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Family ID: |
63080211 |
Appl. No.: |
16/626244 |
Filed: |
June 26, 2018 |
PCT Filed: |
June 26, 2018 |
PCT NO: |
PCT/IB2018/054716 |
371 Date: |
December 23, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62526711 |
Jun 29, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D06M 11/80 20130101;
D04H 1/407 20130101; D06M 10/005 20130101; D04H 1/541 20130101 |
International
Class: |
D06M 10/00 20060101
D06M010/00; D04H 1/407 20120101 D04H001/407; D04H 1/541 20120101
D04H001/541; D06M 11/80 20060101 D06M011/80 |
Claims
1-13. (canceled)
14. A method of making a nonwoven article, the method comprising
exposing a particle coating disposed on a thermally-softenable
nonwoven fiber web to pulsed electromagnetic radiation having at
least one wavelength in the range of 200 to 1000 nanometers,
wherein the particle coating comprises loosely bound distinct
particles that are not chemically bonded to each other and are not
retained in a binder material other than the thermally-softenable
nonwoven fiber web, and wherein the pulsed electromagnetic
radiation has sufficient fluence and pulse width to increase
bonding force between at least a portion of the loosely bound
distinct particles and the thermally-softenable nonwoven fiber
web.
15. The method of claim 14 wherein the particle coating comprises
at least one of graphite or hexagonal boron nitride.
16. The method of claim 14, wherein the particle coating consists
essentially of graphite.
17. The method of claim 14, wherein the pulsed electromagnetic
radiation is generated using a flashlamp.
18. The method of claim 14, wherein the pulsed electromagnetic
radiation is generated using a pulsed laser.
19. The method of claim 14, wherein the pulsed electromagnetic
radiation is generated using a continuous light source and a
shutter.
20. The method of claim 14, wherein the thermally-softenable
nonwoven fiber web comprises fibers having a higher melting core
and a lower melting sheath.
21. A nonwoven article made according to the method of claim 1.
22. A nonwoven article comprising a thermally-softenable nonwoven
fiber web having a particle coating disposed thereon, wherein the
particle coating comprises distinct particles that are not
chemically bonded to each other and are not retained in a binder
material other than the thermally-softenable nonwoven fiber web,
and wherein the particle coating is at least 60 percent retained
after a one minute immersion in isopropanol at 22.degree. C.
23. The nonwoven article of claim 22, wherein the particle coating
comprises at least one of graphite or hexagonal boron nitride.
24. The nonwoven article of claim 22, wherein the particle coating
consists essentially of graphite.
25. The nonwoven article of claim 22, wherein the particle coating
is at least 90 percent retained after the one minute immersion in
isopropanol at 22.degree. C.
26. The nonwoven article of claim 22, wherein the
thermally-softenable nonwoven fiber web comprises fibers having a
higher melting core and a lower melting sheath.
Description
TECHNICAL FIELD
[0001] The present disclosure broadly relates to methods for
improving the durability of particle coatings on nonwoven fiber
webs, and articles preparable thereby.
BACKGROUND
[0002] Coatings of powders (e.g., graphite) on nonwoven fiber webs
are widely known; however, the powders are typically loosely bound
to the fibers and are prone to falling off. Various methods have
been devised to overcome this problem, including: 1) use of a
curable resin applied to the fibers prior to powder coating, and
that when cured securely binds the powder to the fibers; 2) in
those cases where the nonwoven fiber web is durable enough, the
powder may be rubbed onto it in a process known as triboadhesion;
and 3) the powders can be selected to contain binder components
that can fuse to the fibers on heating.
[0003] However, each of these techniques has disadvantages if a
particle coating consisting essentially of inorganic particles is
desired. For example, the presence of binder components in
approaches 1) and 3) would be unacceptable in such a situation, and
durability of particle coatings made by approach 2) is generally
problematic as particle coatings are typically prone to damage by
methods such as abrasion and/or rinsing with solvent.
SUMMARY
[0004] Advantageously, the present disclosure provides an easy
method to enhance the durability of particle coatings that involves
instantaneous heating by exposure to pulsed electromagnetic
radiation having at least one wavelength in the range of 200 nm to
1000 nm. Without wishing to be bound by theory, the present
inventors believe that the modulated electromagnetic radiation
hitting the particles in the particle coating is converted to heat
that is localized adjacent to the particles thereby softening the
adjacent fibers and increasing adhesion between those fibers and
the particles.
[0005] In a first aspect, the present disclosure provides a method
of making a nonwoven article, the method comprising exposing a
particle coating disposed on a thermally-softenable nonwoven fiber
web to pulsed electromagnetic radiation having at least one
wavelength in the range of 200 to 1000 nanometers, wherein the
particle coating comprises loosely bound distinct particles that
are not chemically bonded to each other and are not retained in a
binder material other than the thermally-softenable nonwoven fiber
web, and wherein the pulsed electromagnetic radiation has
sufficient fluence and pulse width to increase bonding force
between at least a portion of the loosely bound distinct particles
and the thermally-softenable nonwoven fiber web.
[0006] By this technique, durability of the particle coating is
improved, while alternative heating methods were prone to damaging
(e.g., warping) the thermally-softenable nonwoven fiber web.
[0007] Accordingly, in a second aspect, the present disclosure
provides a nonwoven article made according to the foregoing method
of the present disclosure.
[0008] In a third aspect, the present disclosure provides a
nonwoven article comprising a thermally-softenable nonwoven fiber
web having a particle coating disposed thereon, wherein the
particle coating comprises distinct particles that are not
chemically bonded to each other and are not retained in a binder
material other than the thermally-softenable nonwoven fiber web,
and wherein the particle coating is at least 60 percent retained
after a one minute immersion in isopropanol at 22.degree. C.
[0009] As used herein:
[0010] The term "visible light" refers to electromagnetic radiation
having a wavelength of 400 to 700 nanometers (nm).
[0011] The term "powder" refers to a free-flowing collection of
minute particles.
[0012] The term "pulsed electromagnetic radiation" refers to
electromagnetic radiation that is modulated to become a series of
discrete spikes with increased intensity. The spikes may be
relative to a background level of electromagnetic radiation that is
negligible or zero, or the background level may be at a higher
level that is substantially ineffective to increase adhesion of
particles in the particle coating to the fiber.
[0013] The term "thermally-softenable" means softenable upon
heating.
[0014] The term "particle coating" refers to a coating of minute
particles which may or may not be free-flowing.
[0015] Features and advantages of the present disclosure will be
further understood upon consideration of the detailed description
as well as the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is an enlarged schematic side view of an exemplary
article 100 according to the present disclosure.
[0017] It should be understood that numerous other modifications
and embodiments can be devised by those skilled in the art, which
fall within the scope and spirit of the principles of the
disclosure.
DETAILED DESCRIPTION
[0018] Advantageously, the present disclosure provides an easy
method to enhance the durability of particle coatings on nonwoven
fiber webs using instantaneous heating by exposure to a modulated
source of electromagnetic radiation.
[0019] Referring now to FIG. 1, exemplary article 100 comprises a
thermally-softenable nonwoven fiber web 110 having a particle
coating 120 disposed thereon.
[0020] Particle coatings on thermally-softenable nonwoven (e.g.,
thermoplastic) fiber webs can be carried out by various known
methods including, for example, exposure to an aerosolized particle
cloud, contact with a powder bed, coating with a solvent-based
particle dispersion coating followed by evaporation of solvent,
and/or powder-rubbed (rubbing dry particles against a substrate to
form a coating of the powder particles). Examples of powder-rubbing
methods can be found in U.S. Pat. No. 6,511,701 B1 (Divigalpitiya
et al.), U.S. Pat. No. 6,025,014 (Stango), and U.S. Pat. No.
4,741,918 (Nagybaczon et al.). The remaining methods will be
familiar to those of ordinary skill in the art.
[0021] Useful particle coatings comprise minute loosely bound
particles capable of absorbing at least one wavelength of the
pulsed electromagnetic radiation, preferably corresponding to a
majority of the energy of the pulsed electromagnetic radiation.
Suitable particles are preferably at least substantially unaffected
by electromagnetic radiation, but are moderate to strong absorbers
of it. This is desirable to maximize the light (electromagnetic
radiation) to heat conversion yield without altering the chemical
nature of the particles.
[0022] Exemplary suitable particles include graphite, clays,
hexagonal boron nitride, pigments, inorganic oxides (e.g., alumina,
calcia, silica, ceria, zinc oxide, or titania), metal(s), organic
polymeric particles (e.g., polytetrafluoroethylene, polyvinylidene
difluoride), carbides (e.g., silicon carbide), flame retardants
(e.g., aluminum trihydrate, aluminum hydroxide, magnesium
hydroxide, sodium hexametaphosphate, organic phosphonates and
phosphates and ester thereof), carbonates (e.g., calcium carbonate,
magnesium carbonate, sodium carbonate), dry biological powders
(e.g., spores, bacteria), and combinations thereof. Preferably, the
particles have an average particle size of 0.1 to 100 micrometers,
more preferably 1 to 50 micrometers, and more preferably 1 to 25
micrometers, although this is not a requirement. Graphite and
hexagonal boron nitride are particularly preferred in many
applications
[0023] Prior to exposure to the electromagnetic radiation the
particle coating comprises loosely bound distinct particles that
are not chemically bonded to each other, and are not retained in a
binder material other than the thermally-softenable nonwoven fiber
web itself.
[0024] The thermally-softenable nonwoven fiber web preferably
comprises thermoplastic fibers, although non-thermoplastic fibers
may be used alone or in combination with thermoplastic fibers, for
example. In preferred embodiments, the fibers of the
thermally-softenable nonwoven fiber web are non-tacky and/or
non-thermosetting, although this is not a requirement.
[0025] Exemplary suitable thermally-softenable nonwoven fiber webs
include meltspun fiber webs, blown microfiber webs, needletacked
staple fiber webs, thermally bonded airlaid webs, and spunlace
webs. The thermally-softenable nonwoven fiber web may be made by
any suitable nonwoven fiber web making process. Examples include
meltspun, blown microfiber (BMF), air-laid processes, wet-laid
processes, and spunlace. These and other methods will be known to
those of skill in the art. Alternatively, a wide array of nonwoven
fiber web comprising thermally-softenable fibers are commercially
available. The thermally-softenable nonwoven fiber web may be of
any basis weight and may be densely compacted or lofty and open,
for example.
[0026] Some examples of thermoplastic polymers that may be suitable
for fiber-forming include polycarbonates, polyesters, polyamides,
polyurethanes, polyacrylics (e.g., polyacrylonitrile), block
copolymers such as styrene-butadiene-styrene and
styrene-isoprene-styrene block copolymers, polyolefins such as
polyethylene, polypropylene, polybutylene, and
poly(4-methyl-1-pentene), and combinations of such resins. Examples
of thermoplastic polymers materials that may be used to make
nonwoven fiber web comprising thermoplastic fibers are disclosed in
U.S. Pat. No. 5,706,804 (Baumann et al.), U.S. Pat. No. 4,419,993
(Peterson), Re 28,102 (Mayhew), U.S. Pat. No. 5,472,481 (Jones et
al.), U.S. Pat. No. 5,411,576 (Jones et al.), and U.S. Pat. No.
5,908,598 (Rousseau et al.). In some preferred methods, at least a
portion of the fibers in the thermoplastic fiber web have a higher
melting core and a lower melting sheath. In such cases, the higher
melting core should preferably be at least 25.degree. C.
[0027] The pulsed electromagnetic radiation may come from any
source(s) capable of generating sufficient fluence and pulse
duration to effect sufficient heating of the nonwoven fiber web to
cause the particle coating to bind more tightly to it. At least
three types of sources may be effective for this purpose:
flashlamps, lasers, and shuttered lamps. The selection of
appropriate sources will typically be influenced by desired process
conditions such as, for example, line speed, line width, spectral
output, and cost.
[0028] Preferably, the pulsed electromagnetic radiation is
generated using a flashlamp. Of these, xenon and krypton flashlamps
are the most common. Both provide a broad continuous output over
the wavelength range 200 to 1000 nanometers, however the krypton
flashlamps have higher relative output intensity in the 750-900 nm
wavelength range as compared to xenon flashlamps which have more
relative output in the 300 to 750 nm wavelength range. In general,
xenon flashlamps are preferred for most applications, and
especially those involving graphite particles. Many suitable xenon
and krypton flashlamps are commercially available from vendors such
as Excelitas Technologies Corp. of Waltham, Mass. and Heraeus of
Hanau, Germany.
[0029] In another embodiment, the pulsed electromagnetic radiation
can be generated using a pulsed laser. Suitable lasers may include,
for example, excimer lasers (e.g., XeF (351 nm), XeCl (308 nm), and
KrF (248 nm)), solid state lasers (e.g., ruby 694 nm)), and
nitrogen lasers (337.1 nm).
[0030] In yet another embodiment, the pulsed electromagnetic
radiation is generated using a continuous light source and a
shutter (preferably a rotating aperture/shutter to reduce
overheating of the shutter). Suitable light sources may include
high-pressure mercury lamps, xenon lamps, and metal-halide
lamps.
[0031] For maximum efficiency, the electromagnetic radiation
spectrum is preferably most intense at wavelength(s) that are
strongly absorbed by the particles, although this is not a
requirement. Likewise, in the case of reflective particles, the
electromagnetic radiation spectrum is preferably most intense in
spectral regions in which the particles are least reflective,
although this is not a requirement.
[0032] Preferably, the source of pulsed electromagnetic radiation
is capable of generating a high fluence (energy density) with high
intensity (high power per unit area), although this is not a
requirement. These conditions assure that the sufficient heat is
absorbed to effect increased adhesion of the particles to the
fibers. However, the combination of intensity and fluence should
not be so great/high as to cause ablation, excessive degradation,
or volatilization of fibers in the nonwoven fiber web. Selection of
appropriate conditions is within the capability of one of ordinary
skill in the art.
[0033] To minimize heating of interior portions of the fibers that
cannot interact with the particles on the nonwoven fiber web, the
pulse duration is preferably short; e.g., less than 10
milliseconds, less than 1 millisecond, less than 100 microseconds,
less than 10 microseconds, or even less than 1 microsecond,
although this is not a requirement.
[0034] To achieve high line speed in continuous manufacturing
processes, not only should the pulsed electromagnetic radiation
preferably be powerful, but the exposure area is preferably large
and the pulse repetition rate is preferably fast (e.g., 100 to 500
Hz).
[0035] In order to evaluate durability, the resultant exposed
particle-coated nonwoven fiber web may be immersed in a solvent
such as, e.g., isopropanol for a fixed interval (e.g., 1, 2, 3, 4,
or even 5 minutes, or longer) at about 22.degree. C. (e.g., room
temperature), and then removed, dried, and weighed. Weight loss of
powder can then be determined by subtraction. The solvent should be
selected such that it does not dissolve the nonwoven fiber web.
[0036] Preferably, the particulate coating of the nonwoven article
is sufficiently bonded to the nonwoven fiber web so that after one
minute of immersion in isopropanol at 22.degree. C. at least 15,
20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or even at
least 90 percent of the particulate coating remains bonded to the
nonwoven fiber web.
SELECT EMBODIMENTS OF THE PRESENT DISCLOSURE
[0037] In a first embodiment, the present disclosure provides a
method of making a nonwoven article, the method comprising exposing
a particle coating disposed on a thermally-softenable nonwoven
fiber web to pulsed electromagnetic radiation having at least one
wavelength in the range of 200 to 1000 nanometers, wherein the
particle coating comprises loosely bound distinct particles that
are not chemically bonded to each other and are not retained in a
binder material other than the thermally-softenable nonwoven fiber
web, and wherein the pulsed electromagnetic radiation has
sufficient fluence and pulse width to increase bonding force
between at least a portion of the loosely bound distinct particles
and the thermally-softenable nonwoven fiber web.
[0038] In a second embodiment, the present disclosure provides a
method according to the first embodiment, wherein the particle
coating comprises at least one of graphite or hexagonal boron
nitride.
[0039] In a third embodiment, the present disclosure provides a
method according to the first or second embodiment, wherein the
particle coating consists essentially of graphite.
[0040] In a fourth embodiment, the present disclosure provides a
method according to any one of the first to third embodiments,
wherein the pulsed electromagnetic radiation is generated using a
flashlamp.
[0041] In a fifth embodiment, the present disclosure provides a
method according to any one of the first to third embodiments,
wherein the pulsed electromagnetic radiation is generated using a
pulsed laser.
[0042] In a sixth embodiment, the present disclosure provides a
method according to any one of the first to third embodiments,
wherein the pulsed electromagnetic radiation is generated using a
continuous light source and a shutter.
[0043] In a seventh embodiment, the present disclosure provides a
method according to any one of the first to sixth embodiments,
wherein the thermally-softenable nonwoven fiber web comprises
fibers having a higher melting core and a lower melting sheath.
[0044] In an eighth embodiment, the present disclosure provides a
nonwoven article made according to any one of the first to seventh
embodiments of the present disclosure.
[0045] In a ninth embodiment, the present disclosure provides a
nonwoven article comprising a thermally-softenable nonwoven fiber
web having a particle coating disposed thereon, wherein the
particle coating comprises distinct particles that are not
chemically bonded to each other and are not retained in a binder
material other than the thermally-softenable nonwoven fiber web,
and wherein the particle coating is at least 60 percent retained
after a one minute immersion in isopropanol at 22.degree. C.
[0046] In a tenth embodiment, the present disclosure provides a
nonwoven article according to the ninth embodiment, wherein the
particle coating comprises at least one of graphite or hexagonal
boron nitride.
[0047] In an eleventh embodiment, the present disclosure provides a
nonwoven article according to the ninth or tenth embodiment,
wherein the particle coating consists essentially of graphite.
[0048] In a twelfth embodiment, the present disclosure provides a
nonwoven article according to any one of the ninth to eleventh
embodiments, wherein the particle coating is at least 90 percent
retained after the one minute immersion in isopropanol at
22.degree. C.
[0049] In a thirteenth embodiment, the present disclosure provides
a nonwoven article according to any one of the ninth to twelfth
embodiments, wherein the thermally-softenable nonwoven fiber web
comprises fibers having a higher melting core and a lower melting
sheath.
[0050] Objects and advantages of this disclosure are further
illustrated by the following non-limiting examples, but 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
[0051] Unless otherwise noted, all parts, percentages, ratios, etc.
in the Examples and the rest of the specification are by weight.
All reagents used in the examples were obtained, or are available,
from general chemical suppliers such as, for example, Sigma-Aldrich
Company, Saint Louis, Missouri, or may be synthesized by
conventional methods.
Materials used in the Examples
TABLE-US-00001 [0052] DESIGNATION DESCRIPTION PE nonwoven Meltblown
linear low density polyethylene nonwoven fiber web, basis weight =
63 g/m.sup.2, 0.33 mm thickness MICRO 850 Graphite powder, 3-5
micrometer particle size, 13 m.sup.2/g surface area, 0.088 ohm cm
resistivity, obtained from Ashbury Graphite Mills, Inc.,
Kittanning, Pennsylvania as MICR0850 Isopropanol (IPA) solvent,
obtained from Aldrich Chemical Company Milwaukee, Wisconsin
General Method for Coating Graphite onto Substrates
[0053] To make Examples and Comparative Examples described below,
graphite coatings were applied on PE nonwoven substrates by placing
a strip of nonwoven approximately 1.5 inches (3.8 cm) by 10 inches
(25.4 cm) in dimension and a small amount of MICRO850 in a sealable
plastic bag. The bag was then sealed and shaken, until the PE
nonwoven was visibly covered in graphite. The nonwoven was then
removed, and excess graphite particles were removed by blowing with
compressed nitrogen at a pressure of 40 pounds per square inch.
[0054] The relative amount of graphite coating deposited on the PE
nonwoven film was determined by measuring the weight of the sample
before and after the process.
General Methods for Determining Durability
[0055] The samples prepared according to Examples and Comparative
Examples described below, were tested for durability (resilience of
coatings).
[0056] Nonwoven samples were completely immersed (i.e., submerged)
in a bath of IPA at room temperature (22.degree. C.) and stirred by
hand for 1 minute. The samples were then removed and spread onto a
clean surface in a chemical hood and allowed to dry completely.
[0057] All reported percentages of graphite retained (% R) were
calculations from the following equation:
% R = 100 .times. M g , i - M g , w M g , i ##EQU00001##
[0058] Where M.sub.g,i is the mass of graphite on the nonwoven just
prior to immersion in isopropanol, and M.sub.g,w is the mass of
graphite remaining on the nonwoven after the wash step.
Examples 1-11 (EX-1 to EX-11) and Comparative Example A (CEX-A)
[0059] CEX-A and EX-1 to EX-12 were graphite coated PE nonwoven
substrates prepared as described above. For CEX-A, the substrate
was not subjected to IPL and was a control sample. EX-1 to EX-11
were prepared by subjecting the samples to an intense pulsed light
irradiation (IPL). In all cases of IPL, the source used was a Xe
flashlamp, commercially obtained from Xenon Corporation,
Wilmington, Mass., as a SINTERON S-2100 Xe flashlamp equipped with
Type C bulb. Samples were placed beneath a quartz plate for the
irradiation process.
[0060] For EX-1, the substrate was treated 1 time at a pulse rate
of 1 Hz and an energy density of 0.1 J/cm.sup.2. The substrate was
then removed and flipped over, and the treatment was repeated on
the backside of the substrate.
[0061] For EX-2, the substrate was treated 3 times at a pulse rate
of 1 Hz and an energy density of 0.1 J/cm.sup.2. The substrate was
then removed and flipped over, and the treatment was repeated on
the backside of the substrate.
[0062] For EX-3, the substrate was treated 5 times at a pulse rate
of 1 Hz and an energy density of 0.1 J/cm.sup.2. The substrate was
then removed and flipped over, and the treatment was repeated on
the backside of the substrate.
[0063] For EX-4, the substrate was treated 1 time at a pulse rate
of 1 Hz and an energy density of 0.2 J/cm.sup.2. The substrate was
then removed and flipped over, and the treatment was repeated on
the backside of the substrate.
[0064] For EX-5, the substrate was treated 3 times at a pulse rate
of 1 Hz and an energy density of 0.2
[0065] J/cm.sup.2. The substrate was then removed and flipped over,
and the treatment was repeated on the backside of the
substrate.
[0066] For EX-6, the substrate was treated 5 times at a pulse rate
of 1 Hz and an energy density of 0.2 J/cm.sup.2. The substrate was
then removed and flipped over, and the treatment was repeated on
the backside of the substrate.
[0067] For EX-7, the substrate was treated 1 time at a pulse rate
of 1 Hz and an energy density of 0.3 J/cm.sup.2. The substrate was
then removed and flipped over, and the treatment was repeated on
the backside of the substrate.
[0068] For EX-8, the substrate was treated 3 times at a pulse rate
of 1 Hz and an energy density of 0.3 J/cm.sup.2. The substrate was
then removed and flipped over, and the treatment was repeated on
the backside of the substrate.
[0069] For EX-9, the substrate was treated 5 times at a pulse rate
of 1 Hz and an energy density of 0.3 J/cm.sup.2. The substrate was
then removed and flipped over, and the treatment was repeated on
the backside of the substrate.
[0070] For EX-10, the substrate was treated 1 time at a pulse rate
of 1 Hz and an energy density of 0.4
[0071] J/cm.sup.2. The substrate was then removed and flipped over,
and the treatment was repeated on the backside of the
substrate.
[0072] For EX-11, the substrate was treated 3 times at a pulse rate
of 1 Hz and an energy density of 0.4 J/cm.sup.2. The substrate was
then removed and flipped over, and the treatment was repeated on
the backside of the substrate.
[0073] Table 1, below, reports the IPL effects on PE nonwoven and
the measured fraction (f) of the graphite coating retained.
TABLE-US-00002 TABLE 1 ENERGY DENSITY IPL PULSES PER PULSE, EXAMPLE
PER SIDE J/cm.sup.2 %R CEX-A 0 0 4.9 EX-1 1 0.1 16.6 EX-2 3 0.1
26.8 EX-3 5 0.1 31.5 EX-4 1 0.2 18.6 EX-5 3 0.2 44.0 EX-6 5 0.2
45.4 EX-7 1 0.3 16.5 EX-8 3 0.3 52.3 EX-9 5 0.3 60.5 EX-10 1 0.4
34.8 EX-11 3 0.4 91.0
[0074] Comparative Examples B-D (CEX-B to CEX-D)
[0075] For CEX-B to CEX-D, samples of nonwoven PE were subjected to
heating in a Model 725G Isotemp laboratory oven (Fisher Scientific,
Hampton, New Hampshire). Samples were placed on an aluminum tray in
a preheated oven for the specified amount of time. Results are
reported in Table 2, below.
TABLE-US-00003 TABLE 2 TEMPERATURE, DURATION, EXAMPLE .degree. C.
minutes %R CEX-B 105 5 27.5 CEX-C 105 15 37.0 CEX-D 105 30 54.8
[0076] All cited references, patents, and patent applications in
the above application for letters patent are herein incorporated by
reference in their entirety in a consistent manner. In the event of
inconsistencies or contradictions between portions of the
incorporated references and this application, the information in
the preceding description shall control. The preceding description,
given in order to enable one of ordinary skill in the art to
practice the claimed disclosure, is not to be construed as limiting
the scope of the disclosure, which is defined by the claims and all
equivalents thereto.
* * * * *