U.S. patent application number 11/617473 was filed with the patent office on 2008-07-03 for process for dyeing a textile web.
This patent application is currently assigned to KIMBERLY-CLARK WORLDWIDE, INC.. Invention is credited to Dennis John DeGroot, Thomas David Ehlert, Michael Joseph Garvey, Robert Allen Janssen, Earl C. McCraw, Patrick Sean McNichols.
Application Number | 20080155762 11/617473 |
Document ID | / |
Family ID | 39581911 |
Filed Date | 2008-07-03 |
United States Patent
Application |
20080155762 |
Kind Code |
A1 |
Janssen; Robert Allen ; et
al. |
July 3, 2008 |
PROCESS FOR DYEING A TEXTILE WEB
Abstract
In a process for dyeing a textile web having a first face and a
second face opposite the first face, dye is applied to the textile
web and the web is then moved in an open configuration thereof over
a contact surface of an ultrasonic vibration system with the
textile web in direct contact with the contact surface of the
ultrasonic vibration system. The ultrasonic vibration system is
operated to impart ultrasonic energy to the textile web to
facilitate the distribution of dye throughout the web. The web is
then moved further in its open configuration through a microwave
application chamber of a microwave system and the microwave system
is operated to impart microwave energy to the web in the microwave
application chamber to facilitate binding of the dye to the
web.
Inventors: |
Janssen; Robert Allen;
(Alpharetta, GA) ; DeGroot; Dennis John;
(Appleton, WI) ; Ehlert; Thomas David; (Neenah,
WI) ; Garvey; Michael Joseph; (Appleton, WI) ;
McCraw; Earl C.; (Duluth, GA) ; McNichols; Patrick
Sean; (Hortonville, WI) |
Correspondence
Address: |
Christopher M. Goff (27839);ARMSTRONG TEASDALE LLP
ONE METROPOLITAN SQUARE, SUITE 2600
ST. LOUIS
MO
63102
US
|
Assignee: |
KIMBERLY-CLARK WORLDWIDE,
INC.
Nennah
WI
|
Family ID: |
39581911 |
Appl. No.: |
11/617473 |
Filed: |
December 28, 2006 |
Current U.S.
Class: |
8/444 |
Current CPC
Class: |
D06P 5/2083 20130101;
D06B 19/007 20130101; D06P 5/2011 20130101; D06B 13/00
20130101 |
Class at
Publication: |
8/444 |
International
Class: |
D06P 5/20 20060101
D06P005/20 |
Claims
1. A process for dyeing a textile web, said textile web having a
first face and a second face opposite the first face, said method
comprising: applying dye to the textile web; moving the web in an
open configuration thereof over a contact surface of an ultrasonic
vibration system with the textile web in direct contact with the
contact surface of the ultrasonic vibration system; operating the
ultrasonic vibration system to impart ultrasonic energy to said
textile web to facilitate the distribution of dye throughout the
web; moving the web in its open configuration through a microwave
application chamber of a microwave system subsequent to imparting
ultrasonic energy to said web; and operating the microwave system
to impart microwave energy to the web in the microwave application
chamber to facilitate binding of the dye to the web.
2. The process set forth in claim 1 wherein the step of applying
dye to the textile web comprises applying dye to the first face of
the web other than by saturating the web.
3. The process set forth in claim 2 wherein the step of moving the
web over the contact surface of an ultrasonic vibration system
comprises moving said web of said contact surface with the second
face of said web in direct contact with said contact surface of the
ultrasonic vibration system.
4. The process set forth in claim 1 wherein the ultrasonic
vibration system has a longitudinal axis, the textile web being
moved in a machine direction from a location upstream from the
contact surface of the ultrasonic vibration system into contact
with the contact surface of the ultrasonic vibration system, said
movement of the web in the machine direction being along an
approach angle relative to said longitudinal axis of the ultrasonic
vibration system, said approach angle being in the range of about 1
to about 89 degrees.
5. The process set forth in claim 4 wherein the approach angle is
in the range of about 10 to about 45 degrees.
6. The process set forth in claim 4 wherein the textile web is
further moved in the machine direction along a departure angle
relative to the longitudinal axis of the ultrasonic vibration
system from said contact of the web with the contact surface of the
ultrasonic vibration system to a location downstream from said
contact surface of the ultrasonic vibration system, said departure
angle being in the range of about 1 to about 89 degrees.
7. The process set forth in claim 1 wherein the textile web has a
width, the process further comprising holding the textile web in
uniform tension across the width of the textile web at least at a
portion of said textile web in direct contact with the contact
surface of the ultrasonic vibration system, said tension being in
the range of about 0.025 to about 3 pounds per inch of width of the
textile web.
8. The process set forth in claim 1 wherein the ultrasonic
vibration system is vibrated at a frequency in the range of about
20 kHz to about 40 kHz.
9. The process set forth in claim 1 wherein the step of operating
the ultrasonic vibration system comprises supplying a power input
to said system, the power input being in the range of about 0.5 kW
to about 2 kw.
10. The process set forth in claim 1 wherein the textile web has a
width, the ultrasonic vibration system comprising an ultrasonic
horn having a terminal end defining said contact surface, said
terminal end of the ultrasonic horn having a width that is
approximately equal to or greater than the width of the web, the
step of moving the web in an open configuration thereof over the
contact surface of an ultrasonic vibration system comprising moving
the web lengthwise over the contact surface of the ultrasonic
vibration system with the terminal end of the ultrasonic vibration
system oriented to extend widthwise across the width of the web
with the contact surface in direct contact with the web.
11. The process set forth in claim 1 wherein the step of operating
the microwave system comprises operating the microwave system at a
frequency in the range of about 900 MHz to about 5,800 MHz.
12. The process set forth in claim 1 wherein the step of operating
the microwave system comprises operating the microwave system at a
power input in the range of about 1,500 watts to about 6,000
watts.
13. The process set forth in claim 1 wherein the microwave
application chamber has a length along which microwave energy is
imparted to the web as the web passes along the length of said
chamber, the step of moving the web through the microwave
application chamber comprising moving the web through said chamber
at a rate relative to said microwave application chamber length to
define a dwell time of the web within said chamber in the range of
about 0.0002 seconds to about 3 seconds.
14. The process set forth in claim 1 wherein the step of applying
dye to the textile web comprises applying a dye having a dielectric
loss factor at 915 MHz of at least about 10 to the textile web.
15. The process set forth in claim 14 wherein the step of applying
dye to the textile web comprises applying a dye having a dielectric
loss factor at 915 MHz of at least about 50 to the textile web.
16. The process set forth in claim 15 wherein the step of applying
dye to the textile web comprises applying a dye having a dielectric
loss factor at 915 MHz of at least about 100 to the textile
web.
17. The process set forth in claim 1 wherein the step of applying
dye to the textile web comprises applying a dye having a dielectric
loss factor at 2,450 MHz of at least about 50 to the textile
web.
18. The process set forth in claim 17 wherein the step of applying
dye to the textile web comprises applying a dye having a dielectric
loss factor at 2,450 MHz of at least about 100 to the textile
web.
19. A process for dyeing a textile web, said textile web having a
first face, a second face opposite the first face and a thickness
from said first face to said second face, said method comprising:
applying dye to the textile web throughout the thickness thereof;
moving the web in an open configuration thereof through a microwave
application chamber of a microwave system subsequent to applying
dye to the web; and operating the microwave system to impart
microwave energy to the web in the microwave application chamber to
facilitate binding of the dye to the web.
20. The process set forth in claim 19 wherein the step of operating
the microwave system comprises operating the microwave system at a
frequency in the range of about 900 MHz to about 5,800 MHz.
21. The process set forth in claim 19 wherein the microwave
application chamber has a length along which microwave energy is
imparted to the web as the web passes along the length of said
chamber, the step of moving the web through the microwave
application chamber comprising moving the web through said chamber
at a rate relative to said microwave application chamber length to
define a dwell time of the web within said chamber in the range of
about 0.0002 seconds to about 3 seconds.
22. The process set forth in claim 19 wherein the step of applying
dye to the textile web comprises applying a dye having a dielectric
loss factor at 915 MHz of at least about 10 to the textile web.
23. The process set forth in claim 22 wherein the step of applying
dye to the textile web comprises applying a dye having a dielectric
loss factor at 915 MHz of at least about 50 to the textile web.
24. The process set forth in claim 23 wherein the step of applying
dye to the textile web comprises applying a dye having a dielectric
loss factor at 915 MHz of at least about 100 to the textile
web.
25. The process set forth in claim 19 wherein the step of applying
dye to the textile web comprises applying a dye having a dielectric
loss factor at 2,450 MHz of at least about 50 to the textile
web.
26. The process set forth in claim 25 wherein the step of applying
dye to the textile web comprises applying a dye having a dielectric
loss factor at 2,450 MHz of at least about 100 to the textile
web.
27. The process set forth in claim 19 wherein the step of operating
the microwave system comprises operating the microwave system at a
power input in the range of about 1,500 watts to about 6,000 watts.
Description
FIELD OF INVENTION
[0001] This invention relates generally to processes for dyeing
textile webs, and more particularly to a process for dyeing a
textile web in which both ultrasonic energy and microwave energy is
used to facilitate the dyeing process.
BACKGROUND
[0002] The dyeing of textile webs is commonly achieved in one of
two manners, one being immersing the textile web into a bath of dye
solution so that the dye soaks into the textile web and the second
being applying dye to (e.g., by spraying or coating) one or both
faces of the textile web. Immersion (also commonly referred to as a
dip-coating process) of the textile web requires a substantial
amount of dye solution to be used to saturate the textile web. In
addition, following saturation the textile web must be washed to
remove a substantial amount of unbound dye from the web. While
dip-coating results in good penetration of the dye throughout the
entire textile web, it presents a relatively inefficient use of the
dye solution and requires considerable post-processing of the
web.
[0003] Dye may instead be applied (such as by spraying or coating)
to one or both faces of the textile web by any number of
application techniques including, without limitation, ink jet
systems, spray systems, gravure roll, slot die, rod coater, rotary
screen curtain coater, air knife, brush and the like. Following the
application of dye to the web, the web is often heated and/or
steamed to promote binding of the dye to the textile web. The
textile web is then washed, such as in a bath of water or other
cleaning solution, to remove unbound and excess dye from the
web.
[0004] Applying dye to the textile web in this manner (e.g., as
opposed to dip-coating) requires considerably less dye to be
initially applied to the web, and thus reduces the time spent
heating/steaming the web to facilitate binding of the dye to the
web, and also reduces the amount of unbound dye that needs to be
subsequently washed from the web. Such dyeing operations where the
dye is applied to only one face of the textile generally use less
dye, but run the associated risk that dye does not adequately
penetrate into and through the web to the opposite face to provide
even or uniform coloring of the web. While dyeing both faces of the
textile web somewhat reduces this risk it also requires additional
dye to be used, resulting in more unbound dye that must be
subsequently removed from the web.
[0005] Once the dye is applied to the web, it is also common to
subject the dyed web to a drying and curing process, such as where
the web is placed in an oven at a suitable temperature to dry the
dye to thereby facilitate binding of the dye to the web. Where webs
are dyed in a continuous, or line feed process, such a drying
process often takes a relatively considerable amount of time
compared to the desired speed at which the web is to be moved.
[0006] There is a need, therefore, for a dyeing process that
reduces the amount of dye that needs to be used in dyeing a textile
web and facilitates improved penetration of the dye into and
through the web and subsequent binding of the dye to the web.
SUMMARY
[0007] In one embodiment, a process for dyeing a textile web having
a first face and a second face opposite the first face generally
comprises applying dye to the textile web and then moving the web
in an open configuration thereof over a contact surface of an
ultrasonic vibration system with the textile web in direct contact
with the contact surface of the ultrasonic vibration system. The
ultrasonic vibration system is operated to impart ultrasonic energy
to the textile web to facilitate the distribution of dye throughout
the web. The web is then moved further in its open configuration
through a microwave application chamber of a microwave system and
the microwave system is operated to impart microwave energy to the
web in the microwave application chamber to facilitate binding of
the dye to the web.
[0008] In another embodiment, a process for dyeing a textile web
having a first face, a second face opposite the first face and a
thickness from the first face to the second face generally
comprises applying dye to the textile web throughout the thickness
thereof. The web is then moved in an open configuration thereof
through a microwave application chamber of a microwave system and
the microwave system is operated to impart microwave energy to the
web in the microwave application chamber to facilitate binding of
the dye in the web.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic of one embodiment of apparatus for
dyeing a textile web according to one embodiment of a process for
dyeing a textile web;
[0010] FIG. 2 is a side elevation of an ultrasonic vibration system
and support frame of the apparatus of FIG. 1;
[0011] FIG. 3 is a front elevation of the ultrasonic vibration
system of the apparatus of FIG. 1;
[0012] FIG. 4 is a side elevation thereof;
[0013] FIG. 5 is a perspective of one embodiment of a microwave
system for use with the apparatus of FIG. 1;
[0014] FIG. 6 is a perspective of a second embodiment of a
microwave system for use with the apparatus of FIG. 1;
[0015] FIG. 7 is a perspective of a third embodiment of a microwave
system for use with the apparatus of FIG. 1;
[0016] FIG. 8 is a perspective of a fourth embodiment of a
microwave system for use with the apparatus of FIG. 1;
[0017] FIG. 9 is a perspective of a fifth embodiment of a microwave
system for use with the apparatus of FIG. 1; and
[0018] FIG. 10 is a perspective of a sixth embodiment of a
microwave system for use with the apparatus of FIG. 1.
[0019] Corresponding reference characters indicate corresponding
parts throughout the drawings.
DETAILED DESCRIPTION
[0020] With reference now to the drawings and in particular to FIG.
1, one embodiment of apparatus for use in dyeing a textile web 23
is generally designated 21. In one suitable embodiment, the textile
web 23 to be processed by the apparatus 21 is suitably a woven web,
but may also be a non-woven web, including without limitation
bonded-carded webs, spunbond webs and meltblown webs, polyesters,
polyolefins, cotton, nylon, silks, hydroknit, coform, nanofiber,
fluff batting, foam, elastomerics, rubber, film laminates,
combinations of these materials or other suitable materials. The
textile web 23 may be a single web layer or a multilayer laminate
in which one or more layers of the laminate are suitable for being
dyed.
[0021] The term "spunbond" refers to small diameter fibers which
are formed by extruding molten thermoplastic material as filaments
from a plurality of fine, usually circular capillaries of a
spinneret with the diameter of the extruded filaments then being
rapidly reduced as by, for example, in U.S. Pat. No. 4,340,563 to
Appel et al., and U.S. Pat. No. 3,692,618 to Dorschner et al., U.S.
Pat. No. 3,802,817 to Matsuki et al., U.S. Pat. Nos. 3,338,992 and
3,341,394 to Kinney, U.S. Pat. No. 3,502,763 to Hartman, and U.S.
Pat. No. 3,542,615 to Dobo et al. Spunbond fibers are generally not
tacky when they are deposited onto a collecting surface. Spunbond
fibers are generally continuous and have average diameters (from a
sample of at least 10) larger than 7 microns, more particularly,
between about 10 and 20 microns.
[0022] The term "meltblown" refers to fibers formed by extruding a
molten thermoplastic material through a plurality of fine, usually
circular, die capillaries as molten threads or filaments into
converging high velocity, usually hot, gas (e.g. air) streams which
attenuate the filaments of molten thermoplastic material to reduce
their diameter, which may be to microfiber diameter. Thereafter,
the meltblown fibers are carried by the high velocity gas stream
and are deposited on a collecting surface to form a web of randomly
dispersed meltblown fibers. Such a process is disclosed, for
example, in U.S. Pat. No. 3,849,241 to Butin et al. Meltblown
fibers are microfibers which may be continuous or discontinuous,
are generally smaller than 10 microns in average diameter, and are
generally tacky when deposited onto a collecting surface.
[0023] Laminates of spunbond and meltblown fibers may be made, for
example, by sequentially depositing onto a moving forming belt
first a spunbond web layer, then a meltblown web layer and last
another spunbond web layer and then bonding the layers together.
Alternatively, the web layers may be made individually, collected
in rolls, and combined in a separate bonding step. Such laminates
usually have a basis weight of from about 0.1 to 12 osy (6 to 400
gsm), or more particularly from about 0.75 to about 3 osy.
[0024] More suitably, the textile web 23 is sufficiently open or
porous so that dye applied to the web may migrate throughout the
thickness of the web. The "porosity" of the textile web 23 is a
measurement of the void space within the textile and is measured
for a particular web specimen in the following manner. For a given
length (in centimeters) and width (in centimeters) of a web
specimen (e.g., over which the web is generally homogeneous and, as
such, has a uniform specific gravity), the specimen is weighed (in
grams) by a suitable balance and the thickness (in centimeters) is
measured using a suitable device, such as a VIR Electronic
Thickness Tester, Model Number 89-1-AB commercially available from
Thwing-Albert Instrument Company of Philadelphia, Pa., U.S.A. A
total volume (in cubic centimeters) of the web specimen is
determined as length.times.width.times.thickness. A material volume
(in cubic centimeters) of the web specimen (i.e., the volume taken
up just by the material in the web specimen) is determined as the
weight of the web specimen divided by the specific gravity (in
grams/cubic centimeter) of the material from which the web is
constructed. The porosity (in percent) of the web specimen is then
determined as ((total volume-material volume)/total
volume).times.100.
[0025] In particularly suitable embodiments, the textile web 23 has
a porosity of at least about 10 percent, and more suitably at least
about 20 percent. In other embodiments the porosity as determined
by the Porosity Test may be at least about 50 and in others the
porosity may be at least about 75. More suitably, the porosity is
in the range of about 10 percent to about 90 percent, and more
suitably in the range of about 20 percent to about 90 percent.
[0026] Some non-limiting examples of suitable textile webs include
a cotton fabric commercially available from Springs Global of Ft.
Mill, S.C., U.S.A. as Spring Global Muslin CPG W/O-SKU 743006050371
(having a basis weight of about 105 grams/square meter (gsm)); a
polyester fabric commercially available from John Boyle &
Company of Statesville, N.C., U.S.A. as Main Street
Fabrics--European Fashion PP--SKU 1713874 (having a basis weight of
about 61 gsm); and a spunbond non-woven web commercially available
from Pegas Nonwovens S.R.O. of Znojmo, Czech Republic as 23 gsm
Pegas PP Liner necked to a basis weight of about 42 gsm. As a
contrasting example, one unsuitable web material is paper, such as
ink jet paper, and in particular ink jet paper commercially
available as RSA Premium Inkjet Paper IJC2436300--24 pound (having
a basis weight of about 92.4 gsm). The following table provides the
porosity for each of these web materials, as determined by using
the above measurement technique on four 7.5 cm.times.7.5 cm web
specimens for each material and averaging the data.
TABLE-US-00001 specific total material pore weight thickness
gravity volume volume volume porosity (grams) (cm) (g/cc) (cc) (cc)
(cc) (percent) Cotton fabric 0.59 0.0288 1.490 1.62 0.39 1.23 76
Polyester fabric 0.35 0.0140 0.930 0.79 0.38 0.41 52 Spunbond 0.25
0.0350 0.900 1.97 0.28 1.70 86 non-woven Inkjet paper 0.52 0.0098
0.929 0.55 0.55 0.00 0
[0027] The dyeing apparatus 21 suitably comprises a dye applicating
device, schematically and generally indicated at 25, operable to
apply dye to at least one of the faces 24a, 24b of the textile web
23. For example, in the embodiment illustrated in FIG. 1, the dye
applicating device is particularly operable to apply dye to only
one face 24a of the textile web. It is understood, however, that
the applicating device may be operable to apply dye only to the
opposite face 24b of the textile web 23, or to both faces of the
web. It is also contemplated that more than one applicating device
may be used (e.g., one corresponding to each face 24a, 24b of the
textile web 23) to apply ink to both faces of the textile web
either concurrently or sequentially.
[0028] The term "dye" as used herein refers to a substance that
imparts more or less permanent color to other materials, such as to
the textile web 23. Suitable dyes include, without limitation,
inks, lakes (also often referred to as color lakes), dyestuffs (for
example but not limited to acid dyes, azoic dyes, basic dyes,
direct dyes, disperse dyes, food, drug and cosmetic dyes, ingrain
dyes, leather dyes, mordant dyes, natural dyes, reactive dyes,
solvent dyes sulfur dyes and vat dyes), pigments (organic and
inorganic) and other colorants (for example but not limited to
fluorescent brighteners, developers, oxidation bases). The dye
suitably has a viscosity in the range of about 2 to about 100
centipoises, more suitably in the range of about 2 to about 20
centipoises, and even more suitably in the range of about 2 to
about 10 centipoises to facilitate flow of the dye into and
throughout the web.
[0029] In a particularly suitable embodiment, the dye is of a
composition that provides an enhanced absorption of microwave
energy, such as by having a relatively high dielectric loss factor.
As used herein, the "dielectric loss factor" is a measure of the
receptivity of a material to high-frequency energy. The measured
value of .epsilon.' is most often referred to as the dielectric
constant, while the measured value of .epsilon.'' is denoted as the
dielectric loss factor. These values can be measured directly using
any suitable measurement devices, such as a Network Analyzer with a
low power, external electric field (i.e., 0 dBm to +5 dBm)
typically over a frequency range of 300 KHz to 3 GHz, although
Network Analyzers to 20 GHz are readily available. Most commonly
dielectric loss factor is measured at a frequency of either 915 MHz
or 2,450 MHz (and at room temperature, such as about 25 degrees
Celsius). For example, one suitable measuring system can include an
HP8720D Dielectric Probe, and a model HP8714C Network Analyzer,
both available from Agilent Technologies of Brookfield, Wis.,
U.S.A. Substantially equivalent devices may also be employed. By
definition .epsilon.'' is always positive, and a value of less than
zero is occasionally observed when .epsilon.' is near zero due to
the measurement error of the analyzer.
[0030] In one particularly suitable embodiment, the dye has a
dielectric loss factor at 915 MHz and 25 degrees Celsius of at
least about 10, more suitably at least about 50, and even more
suitably at least about 100, For comparison purposes, the
dielectric loss factor of water under the same conditions is about
1.2. In another suitable embodiment, the dye has a dielectric loss
factor at 2,450 MHz and 25 degrees Celsius of at least about 25,
more suitably at least about 50, and even more suitably at least
about 100. Water has a dielectric loss factor of about 12 under
these same conditions.
[0031] As an example, the dye may include additives or other
materials to enhance the affinity of the dye to microwave energy.
Examples of such additives and materials include, without
limitation, various mixed valent oxides, such as magnetite, nickel
oxide and the like; carbon, carbon black and graphite; sulfide
semiconductors, such as FeS.sub.2 and CuFeS.sub.2; silicon carbide;
various metal powders such as powders of aluminum, iron and the
like; various hydrated salts and other salts, such as calcium
chloride dihydrate; diatomaceous earth; aliphatic polyesters (e.g.,
polybutylene succinate and poly(butylene succinate-co-adipate),
polymers and copolymers of polylactic acid and polyethylene
glycols; various hygroscopic or water absorbing materials or more
generally polymers or copolymers with many sites of --OH
groups.
[0032] Examples of other suitable inorganic microwave absorbers
include, without limitation, aluminum hydroxide, zinc oxide, barium
titanate. Examples of other suitable organic microwave absorbers
include, without limitation, polymers containing ester, aldehyde
ketone, isocyanate, phenol, nitrile, carboxyl, vinylidene chloride,
ethylene oxide, methylene oxide, epoxy, amine groups, polypyrroles,
polyanilines, polyalkylthiophenes. Mixtures of the above are also
suitable for use in the dye applied to be applied to the textile
web. The selective additive or material may be ionic or dipolar,
such that the applied energy field can activate the molecule.
[0033] Non-limiting examples of suitable dyes that have the desired
dielectric loss factor are inks commercially available from
Yuhan-Kimberly of South Korea under the following designations:
67581-11005579 NanoColorant Cyan 220 ml; 67582-11005580
NanoColorant Magenta 220 ml; 67583-11005581 NanoColorant Yellow 220
ml; 67584-11005582 NanoColorant Black 220 ml; 67587-11005585
NanoColorant Red 220 ml; 67588-11005586 NanoColorant Orange 220 ml;
67591-11005589 NanoColorant Gray 220 ml; 67626-11006045
NanoColorant Violet 220 ml.
[0034] The dye applicating device 25 according to one embodiment
may comprise any suitable device used for applying dye to textile
webs 23 other than by saturating the entire web (e.g., by immersing
the textile web in a bath of dye solution to saturate the web),
whether the dye is pre-metered (e.g., in which little or no excess
dye is applied to the web upon initial application of the dye) or
post-metered (i.e., an excess amount of dye is applied to the
textile web and subsequently removed). It is understood that the
dye itself may be applied to the textile web 23 or the dye may be
used in a dye solution that is applied to the web.
[0035] Examples of suitable pre-metered dye applicating devices 25
include, without limitation, devices for carrying out the following
known applicating techniques:
[0036] Slot die: The dye is metered through a slot in a printing
head directly onto the textile web 23.
[0037] Direct gravure: The dye is in small cells in a gravure roll.
The textile web 23 comes into direct contact with the gravure roll
and the dye in the cells is transferred onto the textile web.
[0038] Offset gravure with reverse roll transfer: Similar to the
direct gravure technique except the gravure roll transfers the
coating material to a second roll. This second roll then comes into
contact with the textile web 23 to transfer dye onto the textile
web.
[0039] Curtain coating: This is a coating head with multiple slots
in it. Dye is metered through these slots and drops a given
distance down onto the textile web 23.
[0040] Slide (Cascade) coating: A technique similar to curtain
coating except the multiple layers of dye come into direct contact
with the textile web 23 upon exiting the coating head. There is no
open gap between the coating head and the textile web 23.
[0041] Forward and reverse roll coating (also known as transfer
roll coating): This consists of a stack of rolls which transfers
the dye from one roll to the next for metering purposes. The final
roll comes into contact with the textile web 23. The moving
direction of the textile web 23 and the rotation of the final roll
determine whether the process is a forward process or a reverse
process.
[0042] Extrusion coating: This technique is similar to the slot die
technique except that the dye is a solid at room temperature. The
dye is heated to melting temperature in the print head and metered
as a liquid through the slot directly onto the textile web 23. Upon
cooling, the dye becomes a solid again.
[0043] Rotary screen: The dye is pumped into a roll which has a
screen surface. A blade inside the roll forces the dye out through
the screen for transfer onto the textile.
[0044] Spray nozzle application: The dye is forced through a spray
nozzle directly onto the textile web 23. The desired amount
(pre-metered) of dye can be applied, or the textile web 23 may be
saturated by the spraying nozzle and then the excess dye can be
squeezed out (post-metered) by passing the textile web through a
nip roller.
[0045] Flexographic printing: The dye is transferred onto a raised
patterned surface of a roll. This patterned roll then contacts the
textile web 23 to transfer the dye onto the textile.
[0046] Digital textile printing: The dye is loaded in an ink jet
cartridge and jetted onto the textile web 23 as the textile web
passes under the ink jet head.
[0047] Examples of suitable post-metering dye applicating devices
for applying the dye to the textile web 23 include without
limitation devices that operate according to the following known
applicating techniques:
[0048] Rod coating: The dye is applied to the surface of the
textile web 23 and excess dye is removed by a rod. A Mayer rod is
the prevalent device for metering off the excess dye.
[0049] Air knife coating: The dye is applied to the surface of the
textile web 23 and excess dye is removed by blowing it off using a
stream of high pressure air.
[0050] Knife coating: The dye is applied to the surface of the
textile web 23 and excess dye is removed by a head in the form of a
knife.
[0051] Blade coating: The dye is applied to the surface of the
textile web 23 and excess dye is removed by a head in the form of a
flat blade.
[0052] Spin coating: The textile web 23 is rotated at high speed
and excess dye applied to the rotating textile web spins off the
surface of the web.
[0053] Fountain coating: The dye is applied to the textile web 23
by a flooded fountain head and excess material is removed by a
blade.
[0054] Brush application: The dye is applied to the textile web 23
by a brush and excess material is regulated by the movement of the
brush across the surface of the web.
[0055] Following the application of dye to the textile web 23, the
textile web is suitably delivered to an ultrasonic vibration
system, generally indicated at 61, having a contact surface 63
(FIG. 2) over which the dyed web 23 passes in contact with the
vibration system such that the vibration system imparts ultrasonic
energy to the web. In the illustrated embodiment, the ultrasonic
vibration system 61 has a terminal end 65, at least a portion of
which defines the contact surface 63 contacted by the textile web
23
[0056] In one particularly suitable embodiment, the textile web 23
is suitably in the form of a generally continuous web, and more
particularly a rolled web wherein the web is unrolled during
processing and then rolled up following processing for transport to
other post-processing stations. For example, as illustrated in
FIGS. 1 and 2, the ultrasonic vibration system 61 may be suitably
mounted on a support frame 67 (FIG. 2) intermediate an unwind roll
45 and a wind roll 49 (the unwind roll and wind roll also being
mounted on suitable respective support frames (not shown)). It is
understood, however, that the textile web 23 may alternatively be
in the form of one or more discrete webs during treatment without
departing from the scope of this invention. The dye applicating
device 25 is located between the unwind roll 45 and the ultrasonic
vibration system to apply dye to the one face 24a of the textile
web before the web advances to the vibration system. It is
understood, however, that dye may be applied to the textile web 23
other than immediately upstream of the ultrasonic vibration system,
such as at a station that is entirely separate from that at which
the web is ultrasonically treated, without departing from the scope
of this invention.
[0057] The textile web 23 is suitably advanced (i.e., moved), such
as by a suitable drive mechanism 51 (FIG. 1) at the wind roll 49,
in a machine direction (indicated by the direction arrows in FIGS.
1 and 2) from the unwind roll past the dye applicating device 25
and the ultrasonic vibration system 61 to the wind roll. The term
"machine direction" as used herein refers generally to the
direction in which the textile web 23 is moved (e.g.,
longitudinally of the web in the illustrated embodiment) during
processing. The term "cross-machine direction" is used herein to
refer to the direction normal to the machine direction of the
textile web 23 and generally in the plane of the web (e.g.,
widthwise of the web in the illustrated embodiment). With
particular reference to FIG. 2, the textile web 23 suitably
advances toward the contact surface 63 (e.g., at the terminal end
65 of the ultrasonic vibration system 61) at an approach angle A1
relative to a longitudinal axis X of the ultrasonic vibration
system 61, and after passing over the contact surface the web
further advances away from the contact surface at a departure angle
B1 relative to the longitudinal axis X of the ultrasonic vibration
system.
[0058] The approach angle A1 of the textile web 23, in one
embodiment, is suitably in the range of about 1 to about 89
degrees, more suitably in the range of about 1 to about 45 degrees,
and even more suitably in the range of about 10 to about 45
degrees. The departure angle B1 of the web 23 is suitably
approximately equal to the approach angle A1 as illustrated in FIG.
2. However, it is understood that the departure angle B1 may be
greater than or less than the approach angle A1 without departing
from the scope of this invention.
[0059] In one particularly suitable embodiment, the ultrasonic
vibration system 61 is adjustably mounted on the support frame 67
for movement relative to the support frame (e.g., vertically in the
embodiment illustrated in FIG. 2) and the unwind and wind rolls 45,
49 to permit adjustment of the contact surface 63 of the ultrasonic
vibration system relative to the web 23 to be treated. For example,
the ultrasonic vibration system 61 is selectively positionable
between a first position (not shown) at which the approach angle A1
and departure angle B1 of the web is substantially zero or at least
relatively small, and a second position illustrated in FIGS. 1 and
2. In the first position of the vibration system 61, the contact
surface 63 of the vibration system may but need not necessarily be
in contact with the textile web 23.
[0060] In the second, or operating position of the ultrasonic
vibration system 61, the terminal end 65 (and hence the contact
surface 63) of the vibration system is substantially spaced from
the first position and is in contact with the textile web 23.
Movement of the vibration system 61 from its first position to its
second position in this embodiment urges the web 23 to along with
the contact surface 63 so as to form the approach and departure
angles A1, B1 of the web.
[0061] Moving the ultrasonic vibration system 61 from its first
position to its second position in this manner may also serve to
tension, or increase the tension in, the textile web 23 at least
along the segment of the web that lies against the contact surface
63 of the vibration system while the web is held between the unwind
roll 45 and the wind roll 49. For example, in one embodiment the
textile web 23 may be held in uniform tension along its width
(i.e., its cross-machine direction dimension), at least at that
segment of the web that is contacted by the contact surface 63 of
the ultrasonic vibration system 61, in the range of about 0.025
pounds/inch of web width to about 3 pounds/inch of web width, and
more suitably in the range of about 0.1 to about 1.25 pounds/inch
of web width.
[0062] In one particularly suitable embodiment, the ultrasonic
vibration system 61 is particularly located relative to the textile
web 23 so that the contact surface 63 of the vibration system
contacts the face 24b of the web opposite the face 24a to which the
dye was initially applied. While in the illustrated embodiment the
dye is applied to the one face 24a of the textile web while the
ultrasonic vibration system 61 contacts the opposite face 24b, it
is understood that the dye may instead be applied to the face 24b
while the ultrasonic vibration system contacts the opposite face
24a.
[0063] With particular reference now to FIG. 3, the ultrasonic
vibration system 61 in one embodiment suitably comprises an
ultrasonic horn, generally indicated at 71, having a terminal end
73 that in the illustrated embodiment defines the terminal end 65
of the vibration system, and more particularly defines the contact
surface 63 of the vibration system. In particular, the ultrasonic
horn 71 of FIG. 3 is suitably configured as what is referred to
herein as an ultrasonic bar (also sometimes referred to as a blade
horn) in which the terminal end 73 of the horn is generally
elongate, e.g., along its width w. The ultrasonic horn 71 in one
embodiment is suitably of unitary construction such that the
contact surface 63 defined by the terminal end 73 of the horn is
continuous across the entire width w of the horn.
[0064] Additionally, the terminal end 73 of the horn 71 is suitably
configured so that the contact surface 63 defined by the terminal
end of the ultrasonic horn is generally flat and rectangular. It is
understood, however, that the horn 71 may be configured so that the
contact surface 63 defined by the terminal end 73 of the horn is
more rounded or other than flat without departing from the scope of
this invention. The ultrasonic horn 71 is suitably oriented
relative to the moving textile web 23 so that the terminal end 73
of the horn extends in the cross-machine direction across the width
of the web. The width w of the horn 71, at least at its terminal
end 73, is suitably sized approximately equal to and may even be
greater than the width of the web.
[0065] A thickness t (FIG. 4) of the ultrasonic horn 71 is suitably
greater at a connection end 75 of the horn (i.e., the longitudinal
end of the horn opposite the terminal end 73 thereof) than at the
terminal end of the horn to facilitate increased vibratory
displacement of the terminal end of the horn during ultrasonic
vibration. As one example, the ultrasonic horn 71 of the
illustrated embodiment of FIGS. 3 and 4 has a thickness t at its
connection end 75 of approximately 1.5 inches (3.81 cm) while its
thickness at the terminal end 73 is approximately 0.5 inches (1.27
cm). The illustrated horn 71 also has a width w of about 6.0 inches
(15.24 cm) and a length (e.g., height in the illustrated
embodiment) of about 5.5 inches (13.97 cm). The thickness t of the
illustrated ultrasonic horn 71 tapers inward as the horn extends
longitudinally toward the terminal end 73. It is understood,
however, that the horn 71 may be configured other than as
illustrated in FIGS. 3 and 4 and remain within the scope of this
invention as long as the horn defines a contact surface 63 of the
vibration system 61 suitable for contacting the textile web 23 to
impart ultrasonic energy to the web.
[0066] The ultrasonic vibration system 61 of the illustrated
embodiment is suitably in the form of what is commonly referred to
as a stack, comprising the ultrasonic horn, a booster 77 coaxially
aligned (e.g., longitudinally) with and connected at one end to the
ultrasonic horn 71 at the connection end 75 of the horn, and a
converter 79 (also sometimes referred to as a transducer) coaxially
aligned with and connected to the opposite end of the booster. The
converter 79 is in electrical communication with a power source or
generator (not shown) to receive electrical energy from the power
source and convert the electrical energy to high frequency
mechanical vibration. For example, one suitable type of converter
79 relies on piezoelectric material to convert the electrical
energy to mechanical vibration.
[0067] The booster 77 is configured to amplify (although it may
instead be configured to reduce, if desired) the amplitude of the
mechanical vibration imparted by the converter 79. The amplified
vibration is then imparted to the ultrasonic horn 71. It is
understood that the booster 77 may instead be omitted from the
ultrasonic vibration system 61 without departing from the scope of
this invention. Construction and operation of a suitable power
source, converter 79 and booster 77 are known to those skilled in
the art and need not be further described herein.
[0068] In one embodiment, the ultrasonic vibration system 61 is
operable (e.g., by the power source) at a frequency in the range of
about 15 kHz to about 100 kHz, more suitably in the range of about
15 kHz to about 60 kHz, and even more suitably in the range of
about 20 kHz to about 40 kHz. The amplitude (e.g., displacement) of
the horn 71, and more particularly the terminal end 73 thereof,
upon ultrasonic vibration may be varied by adjusting the input
power of the power source, with the amplitude generally increasing
with increased input power. For example, in one suitable embodiment
the input power is in the range of about 0.1 kW to about 4 kW, more
suitably in the range of about 0.5 kW to about 2 kW and more
suitably about 1 kW.
[0069] In operation according to one embodiment of a process for
dyeing a textile web, a rolled textile web 23 is initially unwound
from an unwind roll 45, e.g., by the wind roll 49 and drive
mechanism 51, with the web passing the dye applicator 25 and the
ultrasonic vibration system 61. The ultrasonic vibration system 61
is in its second position (as illustrated in FIGS. 1 and 2) with
the terminal end 65 (and hence the contact surface 63) of the
vibration system displaced along with the textile web to the
desired approach and departure angles A1, B1 of the textile web.
The textile web 23 may also be tensioned in the second position of
the vibration system 61 and/or by further winding the wind roll 49,
by back winding the unwind roll 45, by both, or by other suitable
tensioning structure and/or techniques.
[0070] During processing between the unwind roll 45 and the wind
roll 49, the textile web 23 is suitably configured in what is
referred to herein as a generally open configuration as the web
passes over the contact surface 63 of the ultrasonic vibration
system 61. The term "open configuration" is intended to mean that
the textile web 23 is generally flat or otherwise unfolded,
ungathered and untwisted, at least at the segment of the web in
contact with the contact surface 63 of the vibration system 61.
[0071] A feed rate of the web 23 (i.e., the rate at which the web
moves in the machine direction over the contact surface 63 of the
vibration system 61) and the width of the contact surface (i.e.,
the thickness t of the terminal end 73 of the horn 71 in the
illustrated embodiment, or where the contact surface is not flat or
planar, the total length of the contact surface from one side of
the terminal end of the horn to the opposite side thereof)
determine what is referred to herein as the dwell time of the web
on the contact surface of the vibration system. It will be
understood, then, that the term "dwell time" refers herein to the
length of time that a segment of the textile web 23 is in contact
with the contact surface 63 of the vibration system 61 as the web
is drawn over the contact surface (e.g., the width of the contact
surface divided by the feed rate of the web). In one suitable
embodiment, the feed rate of the web 23 across the contact surface
63 of the vibration system 61 is in the range of about 0.5
feet/minute to about 2,000 feet/minute, more suitably in the range
of about 1 feet/minute to about 100 feet/minute and even more
suitably in the range of about 2 feet/minute to about 10
feet/minute. It is understood, however, that the feed rate may be
other than as set forth above without departing from the scope of
this invention.
[0072] In other embodiments, the dwell time is suitably in the
range of about 0.1 second to about 60 seconds, more suitably in the
range of about 1 second to about 10 seconds, and even more suitably
in the range of about 2 seconds to about 5 seconds. It is
understood, however, that the dwell time may be other than as set
forth above depending for example on the material from which the
web 23 is made, the dye composition, the frequency and vibratory
amplitude of the horn 71 of the vibration system 61 and/or other
factors, without departing from the scope of this invention.
[0073] As the textile web 23 passes the dye applicating device 25,
dye is applied to the one face 24a of the web. The ultrasonic
vibration system 61 is operated by the power source to
ultrasonically vibrate the ultrasonic horn 71 as the opposite face
24b of the textile web 23 is drawn over the contact surface 63 of
the vibration system. The horn 71 imparts ultrasonic energy to the
segment of the textile web 23 that is in contact with the contact
surface 63 defined by the terminal end 73 of the horn. Imparting
ultrasonic energy to the opposite face 24b of the textile web 23
facilitates the migration of dye from the one face 24a of the web
into and through the web to the opposite face 24b of the web.
[0074] It is understood, however, that the face 24a (i.e., the face
on which the dye is applied) of the textile web 23 may oppose and
contact the contact surface 63 of the vibration system 61 without
departing from the scope of this invention. It is also contemplated
that a second ultrasonic vibration system (not shown) may be used
to apply ultrasonic energy to the face 24a of the web, either
concurrently or sequentially with the first ultrasonic vibration
system 61 applying ultrasonic energy to the opposite face 24b of
the web.
[0075] With reference now back to FIG. 1, following ultrasonic
treatment of the dyed textile web, the textile web is further
advanced to, and through, a microwave system, generally indicated
at 101 operable to direct high frequency, electromagnetic radiant
energy, and more suitably microwave energy, to the dyed textile web
23 to facilitate expedited and enhanced binding of the dye to the
web. In one particularly suitable embodiment, for example, the
microwave system 101 may employ energy having a frequency in the
range of about 1 MHz to about 5,800 MHz, and more suitably in the
range of about 900 MHz to about 5,800 MHz. In one embodiment the
frequency is more suitably about 915 MHz. In another embodiment the
frequency is more suitably about 2,450 MHz.
[0076] The microwave system 101, with reference to FIG. 5 suitably
comprises a microwave generator 103 operable to produce the desired
amount of microwave energy, a wave-guide 105 and an application
chamber 107 through which the textile web 23 passes while moving in
the machine direction (indicated by the direction arrow in FIG. 5).
For example, the input power of the microwave generator is suitably
in the range of about 1,500 watts to about 6,000 watts. It is
understood, however, that in other embodiments the power input may
be substantially greater, such as about 75,000 watts or more,
without departing from the scope of this invention.
[0077] In a particular embodiment, illustrated in FIG. 6, the
application chamber 107 comprises a housing 126 operatively
connected to the wave-guide 105 and having end walls 128, an
entrance opening (not shown in FIG. 6 but similar to an entrance
opening 102 shown in FIG. 7) for receiving the textile web 23 into
the application chamber, and an outlet opening 104 through which
the textile web exits the application chamber for subsequent
movement to the wind roll 49. The entrance and exit openings 102,
104 can be suitably sized and configured slightly larger than the
textile web 23 so as to allow the textile web, in its open
configuration, to pass through the entrance and exit while
inhibiting an excessive leakage of energy from the application
chamber. The wave-guide 105 and application chamber 107 may be
constructed from suitable non-ferrous, electrically-conductive
materials, such as aluminum, copper, brass, bronze, gold and
silver, as well as combinations thereof.
[0078] The application chamber 107 in one particularly suitable
embodiment is a tuned chamber within which the microwave energy can
produce an operative standing wave. For example, the application
chamber 107 may be configured to be a resonant chamber. Examples of
suitable arrangements for a resonant application chamber 107 are
described in U.S. Pat. No. 5,536,921 entitled SYSTEM FOR APPLYING
MICROWAVE ENERGY 1N SHEET-LIKE MATERIAL by Hedrick et al., issued
Jul. 16, 1996; and in U.S. Pat. No. 5,916,203 entitled COMPOSITE
MATERIAL WITH ELASTICIZED PORTIONS AND A METHOD OF MAKING THE SAME
by Brandon et al, issued Jun. 29, 1999. The entire disclosures of
these documents are incorporated herein by reference in a manner
that is consistent herewith.
[0079] In another embodiment, the effectiveness of the application
chamber 107 can be determined by measuring the power that is
reflected back from the impedance load provided by the combination
of the application chamber 107 and the target material (e.g. the
textile web 23) in the application chamber. In a particular aspect,
the application chamber 107 may be configured to provide a
reflected power which is not more than a maximum of about 50% of
the power that is delivered to the impedance load. The reflected
power can alternatively be not more than about 20% of the delivered
power, and can optionally be not more than about 10% of the
delivered power. In other embodiments, however, the reflected power
may be substantially zero. Alternatively, the reflected power may
be about 1%, or less, of the delivered power, and can optionally be
about 5%, or less, of the delivered power. If the reflected power
is too high, inadequate levels of energy are being absorbed by the
dyed textile web 23 and the power being directed into the dyed web
is being inefficiently utilized.
[0080] The application chamber 107 may also be configured to
provide a Q-factor of at least a minimum of about 200. The Q-factor
can alternatively be at least about 5,000, and can optionally be at
least about 10,000. In other embodiments, the Q-factor can up to
about 20,000, or more. If the Q-factor is too low, inadequate
electrical field strengths are provided to the dyed textile web.
The Q-factor can be determined by the following formula (which may
be found in the book entitled Industrial Microwave Heating by R. C.
Metaxas and R. J. Meredith, published by Peter Peregrinus, Limited,
located in London, England, copyright 1983, reprinted 1993):
Q-factor=f.sub.o/.DELTA.f
[0081] where:
[0082] f.sub.o=intended resonant frequency (typically the frequency
produced by the high-frequency generator), and
[0083] .DELTA.f=frequency separation between the half-power
points.
[0084] In determining the Q-factor, the power absorbed by the dyed
textile web 23 is deemed to be the power delivered into the
application chamber 107 to the web, minus the reflected power
returned from the application chamber. The peak-power is the power
absorbed by the dyed textile web 23 when the power is provided at
the intended resonant frequency, f.sub.o. The half-power points are
the frequencies at which the power absorbed by the dyed textile web
23 falls to one-half of the peak-power.
[0085] For example, a suitable measuring system can include an
HP8720D Dielectric Probe, and a model HP8714C Network Analyzer,
both available from Agilent Technologies, a business having offices
located at Brookfield, Wis., U.S.A. A suitable procedure for
determining the Q-factor is described in the User's Manual dated
1998, part number 08712-90056. Substantially equivalent devices and
procedures may also be employed.
[0086] In another aspect, the application chamber 107 may be
configured for selective tuning to operatively "match" the load
impedance produced by the presence of the target material (e.g. the
dyed textile web 23) in the application chamber. The tuning of the
application chamber 107 can, for example, be provided by any of the
techniques that are useful for "tuning" microwave devices. Such
techniques can include configuring the application chamber 107 to
have a selectively variable geometry, changing the size and/or
shape of a wave-guide aperture, employing adjustable impedance
components (e.g. stub tuners), employing a split-shell movement of
the application chamber, employing a variable frequency energy
source that can be adjusted to change the frequency of the energy
delivered to the application chamber, or employing like techniques,
as well as employing combinations thereof. The variable geometry of
the application chamber 107 can, for example, be provided by a
selected moving of either or both of the end walls 128 to adjust
the distance therebetween.
[0087] As representatively shown in FIGS. 7-10, the tuning feature
may comprise an aperture plate 130 having a selectively sized
aperture 132 or other opening. The aperture plate 130 may be
positioned at or operatively proximate the location at which the
wave-guide 105 joins the application chamber housing 126. The
aperture 132 can be suitably configured and sized to adjust the
waveform and/or wavelength of the energy being directed into the
application chamber 107. Additionally, a stub tuner 134 may be
operatively connected to the wave-guide 105. With reference to FIG.
7, the wave-guide 105 can direct the microwave energy into the
chamber 107 at a location that is interposed between the two end
walls 128. Either or both of the end walls 128 may be movable to
provide selectively positionable end-caps, and either or both of
the end walls may include a variable impedance device, such as
provided by the representatively shown stub tuner 134.
Alternatively, one or more stub tuners 134 may be positioned at
other operative locations in the application chamber 107.
[0088] With reference to FIG. 8, the wave-guide 105 may be arranged
to deliver the microwave energy into one end of the application
chamber 107. Additionally, the end wall 128 at the opposite end of
the chamber 107 may be selectively movable to adjust the distance
between the aperture plate 130 and the end wall 128.
[0089] In the embodiment illustrated in FIG. 9, the application
chamber 107 comprises a housing 126 that is non-rectilinear. In a
further feature, the housing 126 may be divided to provide
operatively movable split portions 126a and 126b. The chamber
split-portions 126a, 126b can be selectively postionable to adjust
the size and shape of the application chamber 107. As
representatively shown, either or both of the end walls 128 are
movable to provide selectively positionable end-caps, and either or
both of the end walls may include a variable impedance device, such
as provided by the representatively shown stub tuner 134.
Alternatively, one or more stub tuners 134 may be positioned at
other operative locations in the chamber 107.
[0090] To tune the application chamber 107, the appointed tuning
components are adjusted and varied in a conventional, iterative
manner to maximize the power into the load (e.g. into the dyed
textile web), and to minimize the reflected power. Accordingly, the
tuning components can be systematically varied to maximize the
power into the textile web 23 and minimize the reflected power. For
example, the reflected power can be detected with a conventional
power sensor, and can be displayed on a conventional power meter.
The reflected power may, for example, be detected at the location
of an isolator. The isolator is a conventional, commercially
available device which is employed to protect a magnetron from
reflected energy. Typically, the isolator is placed between the
magnetron and the wave-guide 105. Suitable power sensors and power
meters are available from commercial vendors. For example, a
suitable power sensor can be provided by a HP E4412 CW power sensor
which is available from Agilent Technologies of Brookfield, Wis.,
U.S.A. A suitable power meter can be provided by a HP E4419B power
meter, also available from Agilent Technologies.
[0091] In the various configurations of the application chamber
107, a properly sized aperture plate 130 and a properly sized
aperture 132 can help reduce the amount of variable tuning
adjustments needed to accommodate a continuous product. The
variable impedance device (e.g. stub tuner 134) can also help to
reduce the amount of variable tuning adjustments needed to
accommodate the processing of a continuous web 23. The
variable-position end walls 128 or end caps can allow for easier
adjustments to accommodate a varying load. The split-housing 126a,
126b (e.g., as illustrated in FIG. 9) configuration of the
application chamber 107 can help accommodate a web 23 having a
varying thickness.
[0092] In another embodiment, illustrated in FIG. 10, the microwave
system 101 may comprise two or more application chamber 107 (e.g.
107a+107b+ . . . ). The plurality of activation chambers 107 can,
for example, be arranged in the representatively shown serial
array.
[0093] As one example of the size of the application chamber 107,
throughout the various embodiments the chamber may suitably have a
machine-directional (indicated by the direction arrow in the
various embodiments) length (e.g., from the entrance 102 to the
exit 104, along which the web is exposed to the microwave energy in
the chamber) of at least about 4 cm. In other aspects, the chamber
107 length can be up to a maximum of about 800 cm, or more. The
chamber 107 length can alternatively be up to about 400 cm, and can
optionally be up to about 200 cm. As more particular examples, the
chamber 107 length is suitably about 4.4 cm. for an operating
frequency of about 5,800 MHz applicator, about 8.9 cm. for an
operating frequency of about 2,450 MHz. and about 25 cm. for an
operating frequency of about 915 MHz for tuned circular cavities.
Such lengths may be much longer for multimode microwave
systems.
[0094] Where the microwave system 101 employs two or more
application chambers 107 arranged in series, the total sum of the
machine-directional lengths provided by the plurality of chambers
may be at least about 10 cm and proportionally longer for lower
frequencies. For example, in other aspects the total of the chamber
107 lengths can be up to a maximum of about 3000 cm, or more. The
total of the chamber 107 lengths can alternatively be up to about
2000 cm, and can optionally be up to about 1000 cm.
[0095] The total residence time within the application chamber 107
or chambers can provide a distinctively efficient dwell time. The
term "dwell time" in reference to the microwave system 101 refers
to the amount of time that a particular portion of the dyed textile
web 23 spends within the application chamber 107, e.g., in moving
from the entrance opening 102 to the exit opening 104 of the
chamber. In a particular aspect, the dwell time is suitably at
least about 0.0002 sec. The dwell time can alternatively be at
least about 0.005 sec, and can optionally be at least about 0.01
sec. In other embodiments the dwell time can be up to a maximum of
about 3 sec, more suitably up to about 2 sec, and optionally up to
about 1.5 sec.
[0096] In operation, after the dyed textile web 23 is moved past
the ultrasonic vibration system 61, which facilitates distribution
of the dye through the thickness of the web, the web is moved
(e.g., drawn, in the illustrated embodiment) through the
application chamber 107 of the microwave system 101. The microwave
system 101 is operated to direct microwave energy into the
application chamber 107 for absorption by the dye (e.g., which in
one embodiment suitably has an affinity for, or couples with, the
microwave energy). The dye is thus heated rapidly, thereby
substantially speeding up the rate at which at the dye becomes
bound to the textile web (e.g., as opposed to conventional heating
methods such as curing in an oven). The web is subsequently moved
downstream of the microwave system 101 for subsequent
post-processing, such as washing to remove any unbound dye, and
other suitable post-processing steps.
[0097] In the illustrated embodiment, the textile web 23 is thus
first subjected to ultrasonic energy to facilitate distribution of
the dye through the web, and then subjected to microwave energy to
facilitate enhanced (and expedited) binding of the dye into the
web. While this combination of processes has been found to result
in better binding of the dye into the web than omitting the
ultrasonic vibration step and just applying the microwave energy to
the web, it is understood that that in other embodiments the web
may be subjected to the microwave energy after the dye application,
thereby omitting the ultrasonic vibration step, without departing
from the scope of this invention. In such an embodiment, it is
contemplated that dye may be initially applied throughout the web
by saturating the web (e.g., by dipping the web in a dye bath) or
by other suitable dyeing techniques that do not involve applying
ultrasonic energy directly to the web.
EXPERIMENT
[0098] An experiment was conducted to determine the effectiveness
of the above process in which the dyed web is subjected first to
ultrasonic vibration and then to microwave energy, and to compare
this effectiveness to that of the above process without the
ultrasonic vibration step (e.g., microwave only), and to a
conventional process in which the dyed web is simply cured in an
oven after being dyed (e.g., no ultrasonics or microwave).
Assessment of these processes was based on the color intensity of
the dye on both the front and back faces of the web after
processing.
[0099] Color is commonly measured by using a spectrodensitometer,
which measures reflected light and provides calorimetric data as
will be described hereinafter. The light which is reflected in the
visual range (i.e., having a wavelength of 400 nm to 700 nm) can be
processed to give a numerical indication of the color. An example
of such a device is the X-Rite 938 reflection spectrodensitometer
available from X-Rite, Incorporated of Grandville, Mich. A suitable
program for analyzing the data generated by this instrument is the
X-Rite QA Master 2000 software available from X-Rite,
Incorporated.
[0100] Color can be described generally in terms of three elements,
hue, chroma (or saturation) and lightness (sometimes called value
or brightness). Hue (h) is the perceived attribute of a specific
color that fixes the color's spectrum position and classifies it as
blue, green, red or yellow. Chroma describes the vividness or
dullness of a color. It is a measurement of how close the color is
to either gray (a mixture of all colors) or to the pure hue. Chroma
(C) can be broken into two measurements: a--the measurement of the
redness or greenness of the color; and b--the measurement of the
yellowness or blueness of the color. The range for a is from -60 to
60, with the range segment from 0 to 60 indicating increasing
saturation of red as you approach 60, and the range segment 0 to
-60 indicating increasing saturation of green as you approach -60.
Chroma is defined as C=(a.sup.2+b.sup.2).sup.1/2. Lightness is the
luminous intensity of a color, or how close the color is to white
or black and ranges in value from 0 (black) to 100 (white). All of
these attributes can be determined using the aforementioned
spectrodensitometer, and analyzed with the QA Master 2000
software.
[0101] For this experiment, a master roll of cotton web
commercially available from Test Fabrics, Inc. of West Pittston,
Pa., U.S.A. as Style No. 419--bleached, mercerized, combed
broadcloth was used as the textile web. The web has a basis weight
of about 120 grams per square meter and is approximately four
inches (about 10.2 cm) wide.
[0102] A black ink, commercially available from Yuhan-Kimberly of
South Korea under the designation 67584 11005582 NanoColorant Black
220 ml was used as the ink solution. The ink applicator was an
electrometric air atomization spray applicator nozzle commercially
available as Spraymation Electromatic Air Atomized Applicator Head,
Model 79200 from Spraymation of Fort Lauderdale, Fla. The ink was
pumped into this nozzle using a Masterflex L/S-Computerized drive
pump, Model number 7550-10 available from Cole Parmer Instrument
Company. The pump was manufactured by Barnant Company of
Barrington, Ill. The applicator was operated at a rate of about 35
grams/square meter.
[0103] For the ultrasonic vibration system, the various components
that were used are commercially available from Dukane Ultrasonics
of St. Charles, Ill., U.S.A as the following model numbers: power
supply--Model 20A3000; converter--Model 110-3123; booster--Model
2179T; and horn Model 11608A. In particular, the horn had a
thickness at its connection end of approximately 1.5 inches (3.81
cm), a thickness at its terminal end of approximately 0.5 inches
(1.27 cm), a width of about 6.0 inches (15.24 cm) and a length
(e.g., height in the illustrated embodiment) of about 5.5 inches
(13.97 cm). The contact surface defined by the terminal end of the
horn was flat, resulting in a contact surface length (e.g.,
approximately equal to the thickness of the horn at its terminal
end) of about 0.5 inches (1.27 cm).
[0104] The microwave system used was similar to that described
above and illustrated in FIG. 5 and operated by a power source
commercially available as National Electronics Model GEN6KW480 from
National Electronics of LaFox, Ill. and capable of delivering up to
6 KW of power. The resonant cavity of the microwave system had a
depth (i.e., in the machine direction of movement of the web
through the cavity) of about 3.5 inches (8.9 cm).
[0105] Three different processes were tested for this experiment:
1) a control in which the web was subjected to oven curing instead
of ultrasonic vibration and microwave energy, 2) a process in which
the web was subjected to microwave energy but not ultrasonic
vibration, and 3) a process in which the web was subjected to both
ultrasonic vibration and microwave energy. For each process, the
master web, in rolled form, was placed on an unwind roll and
unrolled and drawn past the ultrasonic vibration system and through
the microwave system in an open configuration by a suitable wind
roll and drive mechanism at a feed rate of about 4 ft./min. (about
1.2 meters/min.). Before the web reached the ultrasonic vibration
system, the dye solution was sprayed by the dye applicator onto the
face of the web that faces away from the ultrasonic vibration
system (referred to further herein as the front face of the
web).
[0106] The opposite face of the web (i.e., the face that is
opposite that on which the dye was sprayed--referred to further
herein as the back face of the web) was then drawn over the contact
surface of the ultrasonic vibration system (e.g., in direct contact
therewith). This resulted in a dwell time of the web on the contact
surface of the ultrasonic vibration system of about 0.63 seconds. A
uniform tension of approximately one pound per inch of web width
was applied to the web. The approach and departure angles of the
web relative to the longitudinal axis of the ultrasonic vibration
system were each about 20 degrees. The web was subsequently drawn
through the resonant cavity of the microwave system and then to the
wind roll.
[0107] At least about 20 feet of the master roll of web material
was run in accordance with each process to be tested. Once a
particular process run was completed, a representative three foot
sample of the dyed web was cut from the processed web and the L, a
and b values of the sample was measured as described previously for
both the front and back faces of the web. The web sample was then
hand washed in a one gallon bath of detergent mixture comprised of
99.9% by volume of water and 0.1% by volume detergent (available
from Procter and Gamble of Cincinnati, Ohio under the tradename
Joy) to remove unbound dye from the web sample. The bath was
intermittently dumped and refilled with a clean detergent solution
until little or no dye washed out of the web sample. The L, a and b
values for the front and back faces of the web were again measured
after washing. Using the pre-washed color data as a reference, a
".DELTA.E" value was determined as follows:
.DELTA.E=(.DELTA.L.sup.2+.DELTA.a.sup.2+.DELTA.b.sup.2).sup.1/2
i.
[0108] For the control process both the ultrasonic vibration system
and the microwave system were turned off. The web sample cut from
the dyed web was placed in an oven at 180 degrees Celsius for a
period of three minutes prior to taking the pre-wash color data
measurements. For the second process, the ultrasonic vibration
system was turned off while the microwave system was operated at
2,450 MHz and an absorbed power of 200 watts. The third web was
processed with the ultrasonic vibration system operating at 20 kHZ
and the microwave system operated at 2,450 kHZ and an absorbed
power of 200 watts.
[0109] The results of the experiment are summarized in the table
below.
TABLE-US-00002 Process L Description .DELTA.E (after wash) Control
Front Face 1.25 22.73 Back Face 2.05 28.89 Microwave Only Front
Face 4.01 26.53 Back Face 2.10 30.33 Ultrasonic/Microwave Front
Face 1.12 23.69 Back Face 0.86 22.70
[0110] Focusing first on the lightness L, the dye was a black dye
so the nearer to zero the lightness L is, the more "black" the
respective face of the web appears. As is readily seen from the
control, the back face (the face to which the dye solution was not
applied) has a higher lightness L than the front face (to which the
dye was initially applied), which means that the dye solution did
not distribute well through the web from the front face to the back
face of the web. The same is true for the specimen subjected only
to the microwave energy. In contrast, for the specimen subjected to
ultrasonic vibration the dye was more adequately pulled through the
web to the back face thereof, as indicated by the nearly equal
lightness values for the front and back faces of the web.
[0111] The .DELTA.E value provides an indication of the
effectiveness of the tested processes for binding the dye into the
respective web specimens. That is, because the .DELTA.E is based on
the difference of the L, a and b values taken before and after
washing, a positive .DELTA.E means that dye was washed away by the
washing process, thereby slightly fading or rendering less intense
the appearance of the black dye. For the web specimen that was
subjected only to microwave energy (e.g., and not ultrasonic
energy), the .DELTA.E was higher that it was for the control web
specimen. Thus, subjecting the web only to microwave energy does
not itself assure a better binding of the dye into the web.
Subjecting the web to ultrasonic energy before the microwave
energy, however, resulted in a lower .DELTA.E than for the control
process, particularly on the back face of the web. This indicates
that the combination of the ultrasonic energy with the microwave
energy provides and enhanced binding of the dye into the web during
processing.
[0112] When introducing elements of the present invention or
preferred embodiments thereof, the articles "a", "an", "the", and
"said" are intended to mean that there are one or more of the
elements. The terms "comprising", "including", and "having" are
intended to be inclusive and mean that there may be additional
elements other than the listed elements.
[0113] As various changes could be made in the above constructions
and methods without departing from the scope of the invention, it
is intended that all matter contained in the above description and
shown in the accompanying drawings shall be interpreted as
illustrative and not in a limiting sense.
* * * * *