Note: Descriptions are shown in the official language in which they were submitted.
- ~ 95/04955 PCT/US94/08588
216~7~7
MUTABLE COMPOSITION AND
METHODS OF USE THEREOF
Cross-reference to Related Application
This application is a continuation-in-part application
of U.S. Serial No. 08/119,912, filed September 10, 1993, and is a
continuation-in-part application of Serial No. 08/103,503, filed on
August 5, 1993.
Technical Field
The present invention relates to a mutable colored
composition, which, in some embodiments, may be employed in
an electrophotographic toner, e.g., a toner employed in a
photocopier which is based on transfer xerography.
Background of the Invention
Electrophotography is broadly defined as a process in
which photons are captured to create an electrical image analog of
the original. The electrical analog, in turn, is manipulated
through a number of steps which result in a physical image. The
most Gommon form of electrophotography presently in use is
called transfer xerography. Although first demonstrated by C.
Carlson in 1938, the process was slow to gain acceptance. Today,
however, transfer xerography is the foundation of a multi-billion
dollar industry.
The heart of the process is a photoreceptor, usually
the moving element of the process, which is typically either
drum-shaped or a continuous, seamless belt. A corona discharge
~ 95/04955 PCT/US94/08588
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device deposits gas ions on the photoreceptor surface. The ions
provide a uniforrn electric field across the photoreceptor and a
uniform charge layer on its surface. An image of an illllmin~ted
original is projected through a lens system and focused on the
S photoreceptor. Light striking the charged photoreceptor surface
results in increased conductivity across the photoreceptor with the
concomitant neutralization of surface charges. Unilluminated
regions of the photoreceptor surface retain their charges. The
resulting pattern of surface charges is the latent electrostatic
image.
A therrnoplastic pigmented powder or toner, the par-
ticles of which bear a charge opposite to the surface charges on
the photoreceptor, is brought close to the photoreceptor, thereby
permitting toner particles to be attracted to the charged regions
on the photoreceptor surface. The result is a physical image on
the photoreceptor surface consisting of electrostatically held toner
particles.
A sheet of plain paper is brought into physical
contact with the toner-bearing photoreceptor. A charge applied
to the back side of the paper induces the attraction of the toner
image to the paper. The image is a positive image of the original.
The paper then is stripped from the photoreceptor, with the toner
image clinging to it by electrostatic attraction. The toner image is
perrnanently fused to the paper by an appropriate heating means,
such as a hot pressure roll or a radiant heater.
Because there is incomplete transfer of toner to the
paper, it is necessary to clean the photoreceptor surface of
residual toner. Such toner is wiped off with a brush, cloth, or
blade. A corona discharge or reverse polarity aids in the removal
of toner. A unifollll light source then floods the photoreceptor to
neutralize any residual charges from the previous image cycle,
erasing the previous electrostatic image completely and
conditioning the photoreceptor surface for another c~cle.
The toner generally consists of 1-15 micrometer
average diameter particles of a therrnoplastic powder. Black
1 95/W955 PCT/US94108588
- 3 - 2168727
toner typically contains 5-10 percent by weight of carbon black
particles of less than 1 micrometer dispersed in the thermoplastic
powder. For toners employed in color xerography, the carbon
black may be replaced with cyan, magenta, or yellow pigments.
S The concentration and dispersion of the pigment must be adjusted
to impart a conductivity to the toner which is appropriate for the
development system. For most development processes, the toner
is required to retain for extended periods of time the charge
applied by contact electrification. The thermoplastic employed in
the toner in general is selected on the basis of its melting
behavior. The thermoplastic must melt over a relatively narrow
temperature range, yet be stable during storage and able to
withstand the vigorous agitation which occurs in xerographic
development chambers.
The success of electrophotography, and transfer
xerography in particular, no doubt is a significant factor in the
efficient distribution of information which has become essential in
a global setting. It also contributes to the generation of vast
quantities of paper which ultimately must either be disposed of or
recycled. Although the technology for recycling paper exists. it is
costly, time consuming, and generates waste which must be
appropriately disposed of. The conventional method for
recyclmg paper comprises converting paper to pulp, and treating
the pulp to remove ink, toner, and other colored materials, i.e.,
"de-inking" the paper, an expensive and not always completely
successful operation. Moreover, de-inking results in a sludge
which typically is disposed of in a landfill. The resulting de-inked
pulp then is used, often with the addition of at least some virgin
pulp, to form paper, cardboard, cellulosic packaging materials,
and the like.
The simplest form of recycling, however, would be
to reuse the paper intact, thus elimin~*ng the need to re-pulp. To
this end, toners for copier machines have been reported which are
rendered colorless on exposure to near infrared or infrared
radiation. Although the lower wavelength end of the spectrum of
-o 95/04955 PCT/US94/08588
- 4 -
2t68727
sunlight ends at about 375 nanometers. it has a significant infrared
component at the upper wavelength end of the spectrurn. Hence,
such toners have a salient disadvantage in that they are transitory
in the presence of such environmental factors as sunlight and heat;
that is, such toners becom-e colorless. This result is lln~ti.sfactory
because the documents can be rendered illegible before their
function or purpose has ended. Accordingly, there is a need for
toners for copy machines which will perrnit the recycling of
paper intact, but which are stable to normally encountered
environmental factors.
Summary of the Invention
The present invention addresses the need for a
simple, cost-effective. and environmentally sound method for
recycling paper and for the for the multiple reuse of photocopy
paper.
The present invention provides. in general, a colorant
system that is mutable by exposure to radiation. More
particularly, the present invention provides a composition
comprising a colorant which, in the presence of a radiation
transorber, is mutable. The radiation transorber is capable of
absorbing radiation and interacting with the colorant to effect a
mutation of the colorant. In addition, it is desirable that the
mutation of the colorant be irreversible.
The composition of the present invention includes a
colorant and an ultraviolet radiation transorber. The colorant, in
the presence of the ultraviolet radiation transorber, is adapted,
upon exposure of the transorber to ultraviolet radiation, to be
mutable. The ultraviolet radiation transorber is adapted to absorb
ultraviolet radiation and interact with the colorant to effect the
irreversible mutation of the colorant. It is desirable that the
ultraviolet radiation transorber absorb ultraviolet radiation at a
wavelength of from about 4 to about 400 nanometers. It is even
more desirable that the ultraviolet radiation transorber absorb
ultraviolet radiation at a wavelength of 100 to 375 nanometers.
~ 95/049~5 PCTIUS94/08588 ~
2168727
In another embodiment of the present invention, the
colored composition which comprises a colorant and an
ultraviolet radiation transorber may also contain a molecular
includant having a chemical structure which defines at least one
cavity. The molecular includants include, but are not limited to,
clathrates, zeolites, and cyclodextrins. Each of the colorant and
ultraviolet radiation transorber is associated with one or more
molecular includant. In some embodiments, the colorant is at
least partially included within a cavity of the molecular includant
and the ultraviolet radiation transorber is associated with the
molecular includant outside of the cavity. In some embodiments,
the ultraviolet radiation transorber is covalently coupled to the
outside of the molecular includant.
The present invention also relates to a method of
m-lt~ing the colorant in the composition of the present invention.
The method comprises irradiating a composition cont~ining a
mutable colorant and an ultraviolet radiation transorber with
ultraviolet radiation at a dosage level sufficient to mutate the
colorant. As stated above, in some embodirnents, the composition
further includes a molecular includant. In another embodiment,
the composition is applied to a substrate before being irradiated
with ultraviolet radiation. It is desirable that the mutated colorant
is stable. The present invention is also related to a substrate
having an image thereon that is formed by the composition of the
present invention.
The present invention is also related to an
electrophotographic method that allows for the multiple reuse of a
substrate such as photocopy paper. The method comprises
exposing an image on a substrate as produced above, to ultraviolet
radiation at a dosage level sufficient to irreversibly mutate the
colorant. Next, a second image is created on a photoreceptor
surface, and a second toner is applied to the photoreceptor surface
to form a toner image which replicates the second image. Then
the second toner image of the second image is transferred to the
substrate, and the second toner image is fixed to the substrate.
0 95/04955 PCTIUS94/08588
216872~
Where the second toner contains a colorant and a ultraviolet
radiation transorber of the present invention, then the colorant in
the second image may also be mutated by exposure to ultraviolet
radiation, thus allowing the substrate to be reused for the fixation
of a third image to the substrate.
These and other objects, features and advantages of
the present invention will become apparent after a review of the
following detailed description of the disclosed embodiments and
the appended claims.
Brief Description of the Figures
Figure 1 illustrates an ultraviolet radiation
transorber/ mutable colorant/ molecular includant complex
wherein the mutable colorant is malachite green, the ultraviolet
radiation transorber is Irgacure 184 (1-hvdroxycyclohexyl phenyl
ketone), and the molecular includant is ~-cyclodextrin.
Figure 2 illustrates an ultraviolet radiation
transorber/ mutable colorant/ molecular includant complex
wherein the mutable colorant is victoria pure blue BO (Basic Blue
7), the ultraviolet radiation- transorber is Irgacure 184 (1-
hydroxycyclohexyl phenyl ketone), and the molecular includant is
~-cyclode~trin.
Figure 3 is an illustration of several 222 nanometer
excimer lamps arranged in four parallel columns wherein the
twelve numbers represent the locations where twelve intensity
measurements were obtained approximately 5.5 centimeters from
the excimer lamps.
Figure 4 is an illustration of several 222 nanometer
excimer larnps arranged in four parallel colurnns wherein the nine
numbers represent the locations where nine intensity
V 95/04955 PCT/US94/08588
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measurements were obtained approximately 5.5 centimeters from
the excimer lamps.
Figure S is an illustration of several 222 nanometer
excimer lamps arranged in four parallel colums wherein the
location of the number " 1 " denotes the location where ten
intensity measurements were obtained from increasing distances
from the lamps at that location. (The measurements and their
distances from the lamp are sl-mm~rized in Table 7.)
Detailed Description of the Invention
The present invemion relates in general to a colorant
system that is mutable by exposure tO radiation. The present
invention relates to a composition comprising a colorant which, in
the presence of a radiation transorber, is mutable. The radiation
transorber is capable of absorbing radiation and interacting with
the colorant to effect a mutation of the colorant.
More particularly, the composition of the present
invention includes a colorant and an ultraviolet radiation
transorber. The colorant, in the presence of the ultraviolet
radiation transorber, is adapted, upon exposure of the transorber
to ultraviolet radiation, to be mutable. The ultraviolet radiation
transorber is adapted to absorb ultraviolet radiation and interact
with the colorant to effect the irreversible mutation of the
colorant. The term "composition" and such variations as "colored
composition" are used herein to mean a colorant, and an
ultraviolet radiation transorber. When reference is ~eing made to
a colored composition which is adapted for a specific application,
such as a toner to be used in an electrophotographic process, the
term "composition-based" is used as a modifier to indicate that the
material, e.g., a toner, includes a colorant, an ultraviolet radiation
transorber, and, optionally, a molecular includant.
As used herein, the term "colorant" is meant to
include, without limitation, any material which, in the presence of
an ultraviolet radiation transorber, is adapted upon exposure to
95/04955 PCT/US94/08588
2168727
ultraviolet radiation to be mutable. The colorant typically will be
an organic material, such as an organic dye or pigment, including
toners and lakes. Desirably, the colorant will be substantially
transparent to, that is, will not significantly interact with, the
ultraviolet radiation to which it is exposed. The terrn is meant to
include a single material or a mixtllre of two or more materials.
Organic dye classes include, by way of illustration
only, triaryl methyl dyes, such as Malachite Green Carbinol base
{ 4-(dimethylamino)-a-[4-(dimethylamino)phenyl]-a-phenyl-
benzene-methanol~, Malachite Green Carbinol hydrochloride (N-
4-[[4-(dimethylamino)phenyl]-phenylmethylene] -2,5-
cyclohexvldien-l-ylidene]-N-methyl-meth~n~minium chloride or
bis[p-(dimethylamino)phenyl]phenylmethylium chloride~, and
Malachite Green oxalate [ N-4-[[4-
(dimethylamino)phenyl]phenylmethylene]-2,5-cyclohexyldien-1-
ylidene]-N-methylmeth~n~minium chloride or bis[~-(dimethyl-
amino)phenyl]phenylmethylium oxalate); monoazo dyes, such as
Cyanine Black, Chrysoidine [Basic Orange 2; 4-(phenylazo)-1,3-
benzene~ mine monohydrochloride], and 13-Naphthol Orange;
thiazine dyes, such as Methylene Green, zinc chloride double salt
[3,7-bis(dimethylamino)-6-nitrophenothi~7in-5-ium chloride, zinc
chloride double salt]; oxazine dyes, such as Lumichrome (7,8-
dimethylalloxazine); naphth~limide dyes, such as Lucifer Yellow
CH ( 6-amino-2-[(hydrazinocarbonyl)amino]-2,3-dihydro- 1,3-
dioxo-lH-benz[de]iso~uinoline-5,8-disulfonic acid ~lilithillm saltJ;
azine dyes, such as Janus Green B {3-(diethylamino)-7-[[4-
(dimethylamino)phenyl]azo]-5-phenylphenazinium chloride );
cyanine dyes, such as Indocyanine Green (Cardio-Green or Fox
Green; 2-[7-[1,3-dihydro-1,1-dimethyl-3-(4-sulfobutyl)-2H-
benz[e]indol-2-ylidene]-1,3,5-heptatrienyl]-1,1-dimethyl-3-(4-
sulfobutyl)-lH-benz[e]indolium hydroxide inner salt sodium salt~;
indigo dyes, such as Indigo ~Indigo Blue or Vat Blue 1; 2-(1,3-
dihydro-3-oxo-2H-indol-2-ylidene)- 1 ,2-dihydro-3H-indol-3-one ~;
coumarin dyes, such as 7-hydroxy-4-methylcoumarin (4-
methylumbelliferone); benzimidazole dyes, such as Hoechst 33258
~ 95/04955 PCTIUS94/08588
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[bisbenzimide or 2-(4-hydroxyphenyl)-5-(4-methyl- 1 -pipera-
zinyl)-2.5-bi-lH-benzimidazole trihydrochloride pentahydrate~;
paraquinoidal dyes, such as Hematoxylin [Natural Black 1; 7,11b-
dihydrobenz[b]indeno[ 1 ,2-d]pyran-3,4,6a,9, 1 0(6H)-pentol );
fluorescein dyes, such as Fluorescein~mine (5-aminofluorescein);
diazonium salt dyes, such as Diazo Red RC (Azoic Diazo No. 10
or Fast Red RC salt; 2-methoxy-5-chlorobenzenediazonium
chloride, zinc chloride double salt); azoic diazo dyes, such as Fast
Blue BB salt (Azoic Diazo No. 20; 4-benzoylamino-2,5-
diethoxybenzene diazonium chloride, zinc chloride double salt);
phenylene~i~mine dyes, such as Disperse Yellow 9 [N-(2,4-
dinitrophenyl)-1,4-phenylenediamine or Solvent Orange 53];
diazo dyes, such as Disperse Orange 13 [Solvent Orange 52; 1-
phenylazo-4-(4-hydroxyphenylazo)naphthalene]; anthraquinone
dyes, such as Disperse Blue 3 [Celliton Fast Blue FFR; 1-
methylamino-4-(2-hydroxyethylamino)-9, 1 0-anthraguinone],
Disperse Blue 14 [Celliton Fast Blue B; 1,4-bis(methylamino)-
9,10-anthraquinone], and Alizarin Blue Black B (Mordant Black
13); trisazo dyes, such as Direct Blue 71 (Benzo Light Blue FFL
or Sirius Light Blue BRR; 3-[(4-[(4-[(6-amino-1-hydroxy-3-sulfo-
2-naphthalenyl)azo]-6-sulfo- 1 -naphthalenyl)azo]- 1 -naphtha-
lenyl)azo]-1,5-naphthalenedisulfonic acid tetrasodium salt);
xanthene dyes, such as 2,7-dichlorofluorescein; proflavine dyes,
such as 3,6-diaminoacridine hemisulfate (Proflavine);
sulfonaphthalein dyes, such as Cresol Red (o-
cresolsulfonaphthalein); phthalocyanine dyes, such as Copper
Phthalocyanine ~Pigment Blue 15; (SP-4-1)-[29H,31H-
phthalocyanato(2-)-N29,N30,N31,N32]copper3; carotenoid dyes,
such as trans-~-carotene (Food Orange 5); carminic acid dyes,
such as Carmine, the aluminum or calcium-aluminum lake of
carminic acid (7-a-D-glucopyranosyl-9, 1 0-dihydro-3,5,6,8-
tetrahydroxy- 1 -methyl-9, 1 0-dioxo-2-anthracenecarboxylic acid);
azure dyes, such as Azure A [3-amino-7-
(dimethylamino)phenothiazin-5-ium chloride or 7-
(dimethylamino)-3-imino-3H-phenothiazine hydrochloride]; and
-) 95/04955 PCT/US94/08588
lo- 216~7~7
acridine dyes, such as Acridine Orange [Basic Orange 14; 3,8-
bis(dimethylamino)acridine hydrochloride, zinc chloride double
salt] and Acriflavine (Acriflavine neutral; 3,6-diamino- 10-
methylacridinium chloride mixture with 3,6-acridine~ mine).
The term "mutable" with reference to the colorant is
used to mean that the absorption m~ximllm of the colorant in the
visible region of the electrom~netic spectrum is capable of being
mutated or changed by exposure to ultraviolet radiation when in
the presence of the ultraviolet radiation transorber. In general, it
is only necessary that such absorption m~ximllm be mutated to an
absorption maximum which is different from that of the colorant
prior to exposure to the ultraviolet radiation, and that the
mutation be irreversible. Thus, the new absorption maximum can
be within or outside of the visible region of the electromagnetic
spectrum. In other words, the colorant can mllt~te to a different
color or be rendered colorless. The latter, of course, is desirable
when the colorant is used in a colored composition adapted to be
utilized as a toner in an electrophotographic process which reuses
the electrophotographic copy by first rendering the colored
composition colorless and then placing a new irnage thereon.
As used herein, the terrn "irreversible" means that
the colorant will not revert to its ori~inal color when it no longer
is exposed to ultraviolet radiation. Desirably, the mutated
colorant will be stable, i.e., not appreciably adversely affected by
radiation normally encountered in the envirorlment, such as
natural or artificial light and heat. Thus, desirably, a colorant
rendered colorless will remain colorless indefinitely.
The term "ultraviolet radiation transorber" is used
herein to mean any material which is adapted to absorb ultraviolet
radiation and interact with the colorant to effect the mutation of
the colorant. In some embodiments, the ultraviolet radiation
transorber may be an organic compound. The term "compound"
is intended to include a single material or a mixture of two or
more materials. If two or more materials are employed, it is not
') 95/04955 PCT/US94/08588
- ll - 2168727
necessary that all of them absorb ultraviolet radiation of the same
wavelength.
The present invention includes unique compounds
that are capable of absorbing narrow ultraviolet wavelength
radiation. The compounds are synthesized by combining a
wavelength-selective sensitizer and a photoreactor. The
photoreactors oftentimes do not efficiently absorb high energy
radiation. When combined with the wavelength-selective
sensitizer, the resulting compound is a wavelength specific
compound that efficiently absorbs a very narrow spectrum of
radiation. Examples of ultraviolet radiation transorbers are
shown in Examples 5 and 9 herein.
While the mechanism of the interaction of the
ultraviolet radiation transorber with the colorant is not totally
understood, it is believed that it may interact with the colorant in
a variety of ways. For example, the ultraviolet radiation
transorber, upon absorbing ultraviolet radiation, may be
converted to one or more free radicals which interact with the
colorant. Such free radical-generating compounds typically are
hindered ketones, some examples of which include, but are not
limited to: benzildimethyl ketal (available comrnercially as
Irgacure~ 651, Ciba-Geigy Corporation, Hawthome, New York);
1-hydroxycyclohexyl phenyl ketone (Irgacure(~) 500); 2-methyl-l-
[4-(methylthio)phenyl]-2-morpholino-propan- 1 -one] (Irgacure~
907); 2-benzyl-2-dimethylamino- l -(4-morpholinophenyl)butan- 1-
one (Irgacure~) 369); and 1-hydroxycyclohexyl phenyl ketone
(Irgacure~ 184).
Alternatively, the ultraviolet radiation may initiate an
electron transfer or reduction-oxidation reaction between the
ultraviolet radiation transorber and the colorant. In this case, the
ultraviolet radiation transorber may be, but is not limited to,
Michler's ketone (p-dimethylaminophenyl ketone) or benzyl
trimethyl st~nn~te. Or, a cationic mech~ni.~m may be involved, in
which case the ultraviolet radiation transorber could be, for
example, bis[4-(diphenylsulphonio)phenyl)] sulfide bis-
- ~ 95/04955 PCT/US94/08588
- 12- 21~8727
(hexafluorophosphate) (Degacure(~ KI85, Ciba-Geigy
Corporation, Hawthorne, New York); Cyracure(~) UVI-6990
(Ciba-Geigy Corporation), which is a mixture of bis[4-
(diphenylsulphonio)phenyl] sulfide bis(hexafluorophosphate) with
related monosulphonium hexafluorophosphate salts; and 5-2,4-
(cyclopentadienyl)[ 1 ,2,3,4,5,6-(methylethyl)ben~ene]-iron(II)
hexafluorophosphate (Irgacure(~ 261).
The term "ultraviolet radiation" is used herein to
mean electromagnetic radiation having wavelengths in the range
of from about 4 to about 400 nanometers. The especially
desirable ultraviolet radiation range for the present invention is
between approximately 100 to 375 nanometers. Thus, the term
includes the regions commonly referred to as ultraviolet and
vacuum ultraviolet. The wavelength ranges typically assigned to
these two regions are from about 180 to about 400 nanometers
and from about 100 to about 180 nanometers, respectively.
In some embodiments, the molar ratio of ultraviolet
radiation transorber to colorant generally will be equal to or
greater than about 0.5. As a general rule, the more efficient the
ultraviolet radiation transorber is in absorbing the ultraviolet
radiation and interacting with, i.e., transferring absorbed energy
to, the colorant to effect irreversible mutation of the colorant, the
lower such ratio can be. Current theories of molecular photo
chemistry suggest that the lower lirnit to such ratio is 0.5, based
on the generation of two free radicals per photon. As a practical
matter, however, ratios higher than 1 are likely to be required,
perhaps as high as about 10. However, the present invention is
not bound by any specific molar ratio range. The important
feature is that the transorber is present in an arnount sufficient to
effect mutation of the colorant. -
As a practical matter, the colorant, and ultraviolet
radiation transorber are likely to be solids. However, any or all
of such materials can be a liquid. In an embodiment where the
colored composition of the present invention is a solid, the
effectiveness of the ultraviolet radiation transorber is improved
~- ~ 95/0~955 PCT/US94/08588
- 13- 2~6~727
when the colorant and ultraviolet radiation transorber are in
intimate contact. To this end, the thorough blending of the two
components, along with other components which may be present,
is desirable. Such blending generally is accomplished by any of
the means known to those having ordinary skill in the art. When
the colored composition includes a polymer, blending is facilitated
if the colorant and the ultraviolet radiation transorber are at least
partly soluble in softened or molten polymer. In such case, the
composition is readily prepared in, for example, a two-roll mill.
Alternatively, the colored composition can be a liquid because one
or more of its components is a liquid.
For some applications, the colored composition of the
present invention typically will be utilized in particulate form. In
other applications. the particles of the composition should be very
small. For example, the particles of a colored composition
adapted for use as a toner in an electrophotographic process
typically consist of 7-15 micrometer average diameter particles,
although smaller or larger particles can be employed. It is
irnportant to note that the particles should be as uniforrn in size as
possible. Methods of forming such particles are well known to
those having ordinary skill in the art.
Photochemical processes involve the absorption of
light quanta, or photons, by a molecule, e.g., the ultraviolet
radiation transorber, to produce a highly reactive electronically
excited state. However, the photon energy, which is proportional
to the wavelength of the radiation, cannot be absorbed by the
molecule unless it matches the energy difference between the
unexcited, or original, state and an excited state. Consequently,
while the wavelength range of the ultraviolet radiation to which
the colored composition is exposed is not directly of concern, at
least a portion of the radiation must have wavelengths which will
provide the necessary energy to raise the ultraviolet radiation
transorber to an energy level which is capable of interacting with
the colorant.
- ~ 95/04955 PCT/US94/08588
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21~3727
It follows, then, that the absorption maximum of the
ultraviolet radiation transorber ideally will be matched with the
wavelength range of the ultraviolet radiation in order to increase
the efficiency of the mutation of the colorant. Such efficiency
also will be increased if-the wavelength range of the ultraviolet
radiation is relatively narrow, with the maximum of the
ultraviolet radiation transorber coming within such range. For
these reasons, especially suitable ultraviolet radiation has a
wavelength of from about 100 to about 375 nanometers.
Ultraviolet radiation within this range desirably may be
incoherent~ pulsed ultraviolet radiation from a dielectric barrier
discharge excimer lamp.
The term "incoherent, pulsed ultraviolet radiation"
has reference to the radiation produced by a dielectric barrier
lS discharge excimer lamp (referred to hereinafter as "excimer
lamp"). Such a lamp is described, for example, by U.
Kogelschatz, "Silent discharges for the generation of ultraviolet
and vacuum ultraviolet excimer radiation," Pure & Appl. Chem.,
62, No. 9, pp. 1667-1674 (1990); and E. Eliasson and U.
Kogelschatz, "UV Excimer Radiation from Dielectric-Barrier
Discharges," Appl. Phys. B, 46, pp. 299-303 (1988). Excimer
lamps were developed originally by ABB Infocom Ltd.,
Lenzburg, Switzerland. The excimer lamp technology since has
been acquired by Haraus Noblelight AG, Hanau, Germany.
The excimer lamp emits radiation having a very
narrow bandwidth, i.e., radiation in which the half width is of the
order of 5-15 nanometers. This emitted radiation is incoherent
and pulsed, the frequency of the pulses being dependent upon the
frequency of the alternating current power supply which typically
is in the range of from about 20 to about 300 kHz. An excimer
lamp typically is identified or referred to by the wavelength at
which the maximum intensity of the radiation occurs, which
convention is followed throughout this specification. Thus~ in
comparison with most other commercially useful sources of
ultraviolet radiation which typically emit over the entire
- ~ 95/04955 PCT/US94/08588
216~72~
ultraviolet spectrum and even into the visible region, excimer
lamp radiation is subst~nh~lly monochromatic.
Excimers are unstable molecular complexes which
occur only under extreme conditions, such as those temporarily
existing in special types of gas discharge. Typical examples are
thè molecular bonds between two rare gaseous atoms or between a
rare gas atom and a halogen atom. Excimer complexes dissociate
within less than a microsecond and, while they are dissociating,
release their binding energy in the form of ultraviolet radiation.
Known excimers, in general, emit in the range of from about 125
to about 360 nanometers, depending upon the excimer gas
mixture.
Although the colorant and the ultraviolet radiation
transorber have been described as separate compounds, they can
be part of the same molecule. For example, they can be
covalently coupled to each other, either directly, or indirectly
through a relatively small molecule, or spacer. Alternatively, the
colorant and ultraviolet radiation transorber can be covalently
coupled to a large molecule, such as an oligomer or a polymer,
particularly when the solid colored composition of the present
invention is adapted to be utilized as a toner in an
electrophotographic process. Further, the colorant and ultraviolet
radiation transorber may be associated with a large molecule by
van der Waals forces, and hydrogen bonding, among other means.
Other variations will be readily apparent to those having ordinary
skill in the art.
For example, in an embodiment of the composition
of the present invention, the composition further comprises a
molecular includant. The term "molecular includant," as used
herein, is intended to mean any substance having a chemical
structure which defines at least one cavity. That is, the molecular
includant is a cavity-cont~ining structure. As used herein, the
term "cavity" is meant to include any opening or space of a size
sufficient to accept at least a portion of one or both of the
colorant and the ultraviolet radiation transorber. Thus, the cavity
o 9~/04955 PCT/US94/08588
- 16- 216~27
can be a tunnel through the molecular includant or a cave-like
space in the molecular includant. The cavity can be isolated or
independent, or connected to one or more other cavities.
The molecular includant can be inorganic or organic
in nature. In certain embodiments, the chemical structure of the
molecular includant is adapted to form a molecular inclusion
complex. Examples of molecular includants are, by way of
illustration only, clathrates or intercalates, zeolites, and
cyclodextrins. Examples of cyclodextrins include, but are not
limited to, alpha-cyclodextrin, beta-cyclodextrin, gamma-
cyclodextrin, hydroxypropyl beta-cyclodextrin, hydroxyethyl
beta-cyclodextrin, sulfated beta-cyclodextrin, and sulfated
gamma-cyclodextrin. (American Maize-Products Company, of
Hammond Indiana) In some embodiments, the molecular
includant is a cyclodextrin. More particularly, in some
embodiments, the molecular includant is an alpha-cyclodextrin.
In other embodiments, the molecular includant is a beta-
cyclodextrin. Although not wanting to be bound by the following
theory, it is believed that the closer the transorber molecule is to
the mutable colorant on the molecular includant, the more efficent
the interaction with the colorant to effect mutation of the
colorant. Thus, the molecular includant with functional groups
that can react with and bind the transorber molecule and that are
close to the bin~ing site of the mutable colorant are the more
desirable molecular includants.
The colorant and the ultraviolet radiation transorber
are associated with the molecular includant. The term
"associated" in its broadest sense means that the colorant and the
ultraviolet radiation transorber are at least in close proxirnity to
the molecular includant. For example, the colorant and/or the
ultraviolet radiation transorber can be m~int~ined in close
proximity to the molecular includant by hydrogen bonding, van
der Waals forces, or the like. Alternatively, either or both of the
colorant and the ultraviolet radiation transorber can be covalently
bonded to the molecular includant. In certain embodiments, the
- ~ 95/04955 PCT/US94/08588
21&3727
colorant will be associated with the molecular includant by means
of hydrogen bonding and/or van der Waals forces or the like,
while the ultraviolet radiation transorber is covalently bonded to
the molecular includant. In other emborliment~, the colorant is at
least partially included within the cavity of the molecular
includant, and the ultraviolet radiation transorber is located
outside of the cavity of the molecular includant.
In one embodiment wherein the colorant and the
ultraviolet radiation transorber are associated with the molecular
includant, the colorant is cyrstal violet, the ultraviolet radiation
transorber is a dehydrated phthaloylglycine-2959, and the
molecular includant is beta-cyclodextrin. Ln yet another
embodiment wherein the colorant and the ultraviolet radiation
transorber are associated with the molecular includant, the
colorant is crystal violet, the ultraviolet radiation transorber is
4(4-hydroxyphenyl) butan-2-one-2959 (chloro substituted), and
the molecular includant is beta-cyclodextrin.
In another embodiment wherein the colorant and the
ultraviolet radiation transorber are associated with the molecular
includant, the colorant is malachite green, the ultraviolet radiation
transorber is Irgacure 184, and the molecular includant is beta-
cyclodextrin as shown in Figure 1. In still another embodiment
wherein the colorant and the ultraviolet radiation transorber are
associated with the molecular includant, the colorant is victoria
pure blue BO, the ultraviolet radiation transorber is Ir~acure 184,
and the molecular includant is beta-cyclodextrin as shown in
Figure 2.
F.x~mples 5 through 9 disclose a method of preparing
and associating these colorants and ultraviolet radiation
transorbers to beta-cyclodextrins. It is to be understood that the
methods disclosed in Examples S through 9 are merely one way
of preparing and associating these components, and that many
other methods known in the chemical arts may be used. Other
methods of preparing and associated such components. or any of
the other components which may be used in the present invention,
') 95104955 PCT/US94/08588
216~727
would be known to those of ordinary skill in the art once the
specific components have been selected.
As a practical matter, the colorant, ultraviolet
radiation transorber, and molecular includant are likely to be
solids. However, any or all of such materials can be a liquid.
The colored composition can be a liquid either because one or
more of its components is a liquid, or, when the molecular
includant is organic in nature, a solvent is employed. Suitable
solvents include, but are not limited to, amides, such as N,N-
dimethylformamide; sulfoxides, such as dimethylsulfoxide;
ketones. such as acetone, methyl ethyl ketone, and methyl butyl
ketone; aliphatic and aromatic hydrocarbons, such as hexane,
octane, benzene. toluene, and the xylenes; esters, such as ethyl
acetate; water; and the like. When the molecular includant is a
cyclodextrin, particularly suitable solvents are the amides and
sulfoxides.
The present invention also relates to a method of
mutating the colorant in the composition of the present invention.
Briefly described, the method comprises irr~ *ng a composi*on
containing a mutable colorant and an ultraviolet radiation
transorber with ultraviolet radiation at a dosage level sufficient to
mutate the colorant. As stated above, in one embodiment the
composition further includes a molecular includant. In another
embodiment, the composition is applied to a substrate before
being irradiated with ultraviolet radiation.
The amount or dosage level of ultraviolet radiation
that the colorant of the present invention is exposed to will
generally be that amount which is necessary to mutate the
colorant. The amount of ultraviolet radiation necessary to mutate
the colorant can be determined by one of ordinary skill in the art
using routine experiment~tion. Power density is the measure of
the amount of radiated electrom~gnetic power traversing a unit
area and is usually expressed in watts per centirneter squared
( W / c m 2 ) . The power density level ran~e is between
approximately 5 mW/cm2 and 15 mW/cm2, more particularly 8
O 95/W955 PCT/US94/08588
216~72~
to 10 mW/cm2. The dosage level, in turn, typically is a function
of the time of exposure and the intensity or flux of the radiation
source which irradiates the colored composition. The latter is
effected by the distance of the composition from the source and,
depending upon the wavelength range of the ultraviolet radiation,
can be effected by the atmosphere between the radiation source
and the composition. Accordingly, in some instances it may be
appropriate to expose the composition to the radiation in a
controlled atmosphere or in a vacuum, although in general neither
approach is desired.
For example, in one embodiment, the colorant of the
present invention is mutated by exposure to 222 nanometer
- excimer larnps. More particularly, the colorant crystal violet is
mutated by exposure to 222 nanometer lamps. Even more
particularly, the colorant crystal violet is mutated by exposure to
222 nanometer excimer lamps located approximately 5 to 6
centimeters from the colorant, wherein the lamps are arranged in
four parallel columns approximately 30 centimeters long as
shown in Figures 3 and 4. It is to be understood that the
arrangement of the lamps is not critical to this aspect of the
invention. Accordingly, one or more lamps may be arranged in
any configuration and at any distance which results in the colorant
mutating upon exposure to the lamp's ultraviolet radiation. One
of ordinary skill in the art would be able to dete~ ine by routine
experimentation which configurations and which distances are
appropriate. Also, it is to be understood that different excimer
lamps are to be used with different ultraviolet radiation
transorbers. The excimer lamp used to mutate a colorant
associated with an ultraviolet radiation transorber should produce
ultraviolet radiation of a wavelength that is absorbed by the
ultraviolet radiation transorber.
The colored composition of the present invention can
be utilized on or in any substrate. If the composition is present in
a substrate, however, the substrate should be substantially
transparent to the ultraviolet radiation which is employed to
95~04955 PCT/US~1108~88
'~O
2163727
mutate the colorant. That is, the ultraviolet radiation will not
significantly interact with or be absorbed by the substrate. As a
practical matter, the composition typically will be placed on a
substrate, with the most common substrate being paper. Other
substrates, including, but not limited to, woven and nonwoven
webs or fabrics, films, and the like, can be used, however.
Another aspect of the present invention is the
substrate having an image thereon that is formed by the
composition of the present invention. Although the present
invention relates to any substrate capable of having a colored
image fixed thereto, a desirable substrate is paper. Especially
desirable substrates include, but are not limited tot photocopy
paper and facsimile paper.
By way of example, the composition of the present
invention can be incorporated into a toner adapted to be utilized
in an electrophotographic process. The toner includes the
colorant, ultraviolet radiation transorber, and a carrier. The
carrier can be a polymer, and the toner may further contain a
charge carrier. Briefly described, the electrophotographic
process comprises the steps of creating an image on a
photoreceptor surface, applying toner to the photoreceptor
surface to form a toner image which replicates the image,
transferring the toner image to a substrate, and fixing the toner
image to the substrate. After the toner has been fixed on the
substrate, the colorant in the composition is mutated by
irr~di~tin~ the substrate with ultraviolet radiation at a dosage
level sufficient to irreversibly mutate the colorant. In some
embodiments, the ultraviolet radiation used in the method to
mutate the colorant will have wavelen~ths of from about 100 to
about 375 nanometers. In other embodirnents, the ultraviolet
radiation is incoherent, pulsed ultraviolet radiation produced by a
dielectric barrier discharge excimer lamp. In another
embodiment, the toner may further comprise a molecular
includant.
~ 9S/04955 PCT/US94/08588
216~7~7
When the colored composition is adapted to be
utilized as a toner in an electrophotographic process, the
composition also will contain a carrier, the nature of which is
well known to those having-ordinary skill in the art. For many
S applications, the carrier will be a polymer, typically a
thermosetting or thermoplastic polymer, with the latter being the
more comrnon.
Further examples of thermoplastic polymers include,
but are not limited to: end-capped polyacetals, such as
poly(oxymethylene) or polyformaldehyde,
poly(trichloroacetaldehyde), poly(n-valeraldehyde),
poly(acetaldehyde), poly(propionaldehyde), and the like; acrylic
polymers~ such as polyacrylamide, poly(acrylic acid),
poly(methacrylic acid), poly(ethyl acrylate), poly(methyl
methacrylate), and the like; fluorocarbon polvmers, such as
poly(tetrafluoroethylene), perfluorinated ethylenepropylene
copolymers, ethylenetetrafluoroethylene copolymers, poly-
(chlorotrifluoroethylene), ethylene-chlorotrifluoroethylene
copolymers, poly(vinylidene fluoride), poly(vinyl fluoride), and
the like; epoxy resins, such as the condensation products of
epichlorohydrin and bisphenol A; polyamides, such as poly(6-
aminocaproic acid) or poly(E-caprolactam), poly(hexamethylene
adipamide), poly(hexamethylene sebacamide), poly( 1 1-
aminoundecanoic acid), and the like; polyaramides, such as
poly(imino-1,3-phenyleneiminoisophthaloyl) or poly(m-phenylene
isophth~l~mide), and the like; parylenes, such as poly-p-xylylene,
poly(chloro-p-xylene), and the like; polyaryl ethers, such as
poly(oxy-2,6-dimethyl- 1 ,4-phenylene) or poly(p-phenylene
oxide), and the like; polyaryl sulfones, such as poly(oxy-1,4-
phenylenesulfonyl- 1 ,4-phenyleneoxy- 1 ,4-phenylene-
isopropylidene- 1 ,4-phenylene), poly(sulfonyl- 1 ,4-phenyleneoxy-
1,4-phenylenesulfonyl-4,4-biphenylene), and the like;
polycarbonates, such as poly(bisphenol A) or poly(carbonyldioxy-
1 ,4-phenyleneisopropylidene- 1 ,4-phenylene), and the like;
polyesters, such as poly(ethylene terephthalate),
~ 95104955 PCT/US94/08588
- 2~6~7~7
poly(tetramethylene terephthalate), poly(cyclohexylene- 1,4-
dimethylene terephthalate) or poly(oxymethylene- 1,4-
cyclohexylenemethyleneoxyterephthaloyl), and the like; polyaryl
sulfides, such as poly(p-phenylene sulfide) or poly(thio-1,4-
phenylene), and the- like; polyimides, such as poly-
(pyromellitimido-1,4-phenylene), and the like; polyolefins, such
as polyethylene, polypropylene, poly(l-butene), poly(2-butene),
poly( 1 -pentene), poly(2-pentene), poly(3-methyl- 1 -pentene),
poly(4-methyl- 1 -pentene), 1 ,2-poly- 1 ,3-butadiene, 1 ,4-poly- 1,3 -
butadiene, polyisoprene, polychloroprene, polyacrylonitrile,
poly(vinyl acetate), poly(vinylidene chloride), polystyrene, and
the like; and copolymers of the foregoing, such as acrylonitrile-
butadienestyrene (ABS) copolymers, styrene-n-butylmethacrylate
copolymers, ethylene-vinyl acetate copolymers. and the like.
Some of the more comrnonly used thermoplastic
polymers include styrene-n-butyl methacrylate copolymers,
polystyrene, styrene-n-butyl acrylate copolymers, styrene-
butadiene copolymers, polycarbonates, poly(methyl
methacrylate), poly(vinylidene fluoride), polyamides (nylon-12),
polyethylene, polypropylene, ethylene-vinyl acetate copolymers,
and epoxy resins.
Examples of thermosettin,~ polymers include, but are
not limited to, aLkyd resins, such as phthalic ~nhydride-glycerol
resins, maleic acid-glycerol resins, adipic acid-glycerol resins,
and phthalic anhydride-pentaerythritol resins; allylic resins, in
which such monomers as diallyl phth~l~te, diallyl isophthalate
diallyl maleate, and diallyl chlorendate serve as nonvolatile cross-
linking agents in polyester compounds; arnino resins, such as
aniline-formaldehyde resins, ethylene urea-formaldehyde resins,
dicyandiamide-formaldehyde resins, melamine-formaldehyde
resins, sulfonamide-formaldehyde resins, and urea-formaldehyde
resins; epoxy resins, such as cross-linked epichlorohydrin-
bisphenol A resins; phenolic resins, such as phenol-forrnaldehyde
resins, including Novolacs and resols; and thermosetting
polyesters, silicones, and urethanes.
0 95104955 PCT/US94/08588
--3- 2:16~727
In addition to the colorant, and ultraviolet radiation
transorber, and optional carrier, the colored composition of the
present invention also can contain additional components,
depending upon the application for which it is intended. For
example, a composition which is to be utilized as a toner in an
electrophotographic process optionally can contain, for example,
charge carriers, stabilizers against therrnal oxidation, viscoelastic
properties modifiers, cross-linking agents, plasticizers, and the
like. Further, a composition which is to be utilized as a toner in
an electrophotographic process optionally can contain charge
control additives such as a quaternary ammonium salt; flow
control additives such as hydrophobic silica, zinc stearate, calcium
stearate, lithium stearate, polyvinylstearate, and polyethylene
powders; and fillers such as calcium carbonate, clay and talc,
among other additives used by those having ordinary skill in the
art. For some applications, the charge carrier will be the major
component of the toner. Charge carriers, of course, are well
known to those having ordinary skill in the art and typically are
polymer-coated metal particles. The identities and amounts of
such additional components in the colored composition are well
known to one of ordinary skill in the art. Further, the toner of
the present invention, can also include a molecular includant as
described above.
When the colored composition is employed as a toner
for an electrophotographic process, several variations are possible
and come within the scope of the present invention. For example,
the composition-based toner can be used to form a first image on
a virgin paper sheet. The sheet then can be recycled by exposing
the sheet to ultraviolet radiation in accordance with the present
invention to render the colorant, and, as a consequence, the
composition, colorless. A second image then can be forrned on
the sheet. The second image can be formed from a standard,
known toner, or from a composition-based toner which is either
the same as or different from the composition-based toner which
was used to form the first image. If a composition-based toner is
216~727
-24- pcrlus 94/0~588
IPEA/US 2 ~ FEB l~95
used to form the second irnage, the sheet can be recycled again,
with the number of cycles being limited by the build-up of now
colorless composition on the surface of the paper. Further, any
subsequent image can be placed on either side of the sheet. That
is, it is not required that a second image be forrned on the side of
the sheet on which the first image was forrned.
In addition, the conversion of the composition-based
toner image on the sheet to a colorless form does not have to take
place on the sheet. For example, sheets having images forrned
from composition-based toners can be recycled in the traditional
way. In place of the usual de-inking step, however, the sheets are
exposed to ultraviolet radiation, either before or after being
converted to pulp. Where the sheets are exposed to ultraviolet
radiation after being converted to pulp, one of ordinary skill in
the art would understand that no component of the pulp would
interfere with the capability of the ultraviolet radiation transorber
to mutate the colorant upon its exposure to ultraviolet radiation.
The colorless toner then simply becomes incorporated into the
paper formed from the resulting pulp.
The present invention is further described by the
examples which follow. Such examples, however, are not to be
construed as limiting in any way either the spirit or scope of the
present invention. Ln the examples, all parts are parts by weight
unless stated otherwise.
EXAMPLE 1
This example describes the preparation of films
consisting of colorant, ultraviolet radiation transorber, and
thermoplastic polymer. The colorant and ultraviolet radiation
transorber were ground separately in a mortar. The desired
amounts of the ground components were weighed and placed in an
aluminum pan, along with a weighed amount of a thermoplastic
polymer. The pan was placed on a hot plate set at 150C and the
mixture in the pan was stirred until molten. A few drops of the
molten mixture were poured onto a steel plate and spread into a
?,r` ~ ~ S~FF~
' 95/04955 PCT/US94/08588
--5- 2168727
thin film by means of a glass microscope slide. Each steel plate
was 3 x 5 inches (7.6 cm x 12.7 cm) and was obtained from Q-
Panel Company, Cleveland, Ohio. The film on the steel plate was
estimated to have a thickness of the order of 10-20 micrometers.
In every instance, the colorant was Malachite Green
oxalate (Aldrich Chemical Company, Inc., Milwaukee,
Wisconsin), referred to hereinafter as Colorant A for
convenience. The ultraviolet radiation transorber ("UVRT")
consisted of one or more of Irgacure~) 500 ("UVRT A"),
Irgacure~) 651 ("UVRT B"), and Irgacure(~) 907 ("UVRT C"),
each of which was described earlier and is available from Ciba-
Geigy Corporation, Hawthorne, New York. The polymer was
one of the following: an epichlorohydrin-bisphenol A epoxy
resin ("Polymer A"), Epon~) 1 004F (Shell Oil Company,
Houston, Texas); a poly(ethylene glycol) having a weight-average
molecular weight of about 8,000 ("Polymer B"), Carbowax 8000
(Aldrich Chemical Company); and a poly(ethylene glycol) having
a weight-average molecular weight of about 4,600 ("Polymer C"),
Carbowax 4600 (Aldrich Chemical Company). A control film
was prepared which consisted only of colorant and polymer. The
composinons of the films are sllmm~rized in Table 1.
'O 95/04955 PCTIUS94/08588
- 26 - 2 ~ 6 ~ 7 2 ~
Table 1
Compositions of Films Containing
Colorant and Ultraviolet Radiation Transorber
("UVRT")
S
Colorant UVRT Polyrner
Film Tvpe Parts Tvpe Parts Tvpe Parts
A A l A 6 A 90
C 4
B A 1 A 12 A 90
C 8
C A 1 A 18 A 90
C 12
D A 1 A 6 A 90
B 4
E A 1 B 30 A 70
F A l -- -- A lO0
G A l A 6 B 90
C 4
H A l B l O C 90
While still on the steel plate, each film was exposed
to ultraviolet radiation. In each case. the steel plate having the
film sample on its surface was placed on a moving conveyor belt
having a variable speed control. Three different ultraviolet
radiation sources, or lamps, were used. Lamp A was a 222-
nanometer excimer lamp and Lamp B was a 308-nanometer
excimer lamp, as already described. Lamp C was a fusion larnp
system having a "D" bulb (Fusion Systems Corporation,
Rockville, Maryland). The excimer lamps were organized in
banks of four cylindrical larnps having a length of about 30 cm,
with the lamps being oriented normal to the direction of motion
of the belt. The lamps were cooled by circulating water through a
centrally located or inner tube of the lamp and. as a consequence,
they operated at a relatively low temperature. i.e., about 50C.
95/04955 PCT/US94/08588
-'~7- 216~727
The power density at the lamp's outer surface typically is in the
range of from about 4 to about 20 joules per square meter (J/m2).
However, such range in reality merely reflects the
capabilities of current excimer lamp power supplies; in the future,
higher power densities may be practical. With Lamps A and B,
the distance from the lamp to the film sample was 4.5 cm and the
belt was set to move at 20 ft/min (0.1 m/sec). With Lamp C, the
belt speed was 14 ft/min (0.07 m/sec) and the larnp-to-sample
distance was 10 cm. The results of exposing the film samples to
ultraviolet radiation are s--mm~rized in Table 2. Except for Film
F, the table records the number of passes under a lamp which
were required in order to render the film colorless. For Film F,
the table records the number of passes tried, with the film in each
case rem~ining colored (no change).
Table 2
Results of Exposing Films Containing
Colorant and Ultraviolet Radiation Transorber (UVRT)
to Ultraviolet Radiation
Excimer Lamp
Film Lamp A Lamp B Fusion Lamp
A 3 3 15
B 2 3 10
C 1 3 10
D 1 1 10
E
F 5 5 10
G 3 -- 10
H 3 -- lO
EXAMPLE 2
This example describes the preparation of solid
colored compositions adapted to be utilized as toners in an
electrophotographic process. In every instance, the toner
95/W9SS PCTIUS94/08588
- 28 - 216~727
included Colorant A as described in Example l; a polymer, DER
667, an epichlorohydrin-bisphenol A epoxy resin (Polymer D),
Epon(~ 1004F (Dow Chemical Company, Midland, Michigan);
and a charge carrier, Carrier A, which consisted of a very finely
S divided polymer-coated metal. The ultraviolet radiation
transorber (UVRT) consisted of one or more of UVRT B from
Example 1, Irgacure(~) 369 (UVRT D), and Irgacure~) 184
(UVRT E); the latter two transorbers were described earlier and
are available from Ciba-Geigy Corporation, Hawthorne, New
York. In one case, a second polymer also was present, styrene
acrylate 1221, a styrene-acrylic acid copolymer (Hercules
Incorporated, Wilmington, Delaware).
To prepare the toner, colorant, ultraviolet radiation
transorber, and polymer were melt-blended in a Model 3VV
800E, 3 inch x 7 inch (7.6 cm x 17.8 cm) two-roll research mill
(Farrel Corporation, Ansonia, Connecticut). The resulting melt-
blend was powdered in a Mikropul h~mm~rmill with a 0.010-inch
herringbone screen (R. D. Kleinfeldt, Cincinnati, Ohio) and then
sieved for proper particle sizes in a Sturtvant, air two-inch
micronizer (R. D. Kleinfeldt) to give what is referred to herein as
a pretoner. Charge carrier then was added to the pretoner and
the resulting mixture blended thoroughly. Table 3 s-lmm~rizes the
compositions of the pretoners and Table 4 sl-mm~rizes the
compositions of the toners.
95/04955 PCT/US94108588
29
216~727
Table 3
Summary of Pretoner Compositions
Colorant UVRT Polymer
Pretoner A (g) Tvpe g Tvpe g
A 1 D 20 D 80
B 1 B 20 D 80
C 1 B 10 D 80
D 10
D 1 B 6.9 D 40
D 6.6 E 40
E 6.6
Table 4
Summary of Toner Compositions
Pretoner Charge
Toner Tvpe g Carrier (g)
A A8.4 210
B B8.4 210
C C8.4 210
D D8.4 210
Each toner was placed separately in a Sharp Model ZT-
50TD1 toner cartridge and installed in either a Sharp Model Z-76
or a Sharp Model Z-77 xerographic copier (Sharp Electronics
Corporation, Mahwah, New Jersey). Images were made in the
usual manner on bond paper (Neenah Bond). The image-bearing
sheets then were exposed to ultraviolet radiation from Lamp B as
described in Example 1. In each case, the image was rendered
colorless with one pass.
~ 95/04955 PCTIUS94108588
- 30 - 216~727
EXAMPLE 3
This example describes the preparation of a ~-cyclodextrin
molecular includant having (1) an ultraviolet radiation transorber
S covalently bonded to the cyclodextrin outside of the cavity of the
cyclodextrin and (2) a colorant associated with the cyclodextrin
by means of hydrogen bonds and/or van der Waals forces.
A . Friedel-Crafts Acvlation of Transorber
A 250-ml, three-necked, round-bottomed reaction
flask was fitted with a condenser and a pressure-equalizing
addition funnel equipped with a nitrogen inlet tube. A magnetic
stirring bar was placed in the flask. While being flushed with
nitrogen, the flask was charged with 10 g (0.05 mole) of
1-hydroxvcyclohexyl phenyl ketone (Irgacure~ 184, Ciba-Geigy
Corporation, Hawthorne, New York), 100 ml of anhydrous
tetrahydofuran (Aldrich Chemical Company, Inc., Milwaukee,
Wisconsin), and S g (0.05 mole) of succinic anhydride (Aldrich).
To the continuously stirred contents of the flask then was added
6.7 g of anhydrous aluminum chloride (Aldrich). The resulting
reaction mixture was m~int~ined at about 0C in an ice bath for
about one hour, after which the mixture was allowed to warm to
ambient temperature for two hours. The reaction mixture then
was poured into a mixture of 500 ml of ice water and 100 ml of
diethyl ether. The ether layer was removed after the addition of a
small amount of sodium chloride to the aqueous phase to aid phase
separation. The ether layer was dried over anhydrous magnesium
sulfate. The ether was removed under reduced pressure, leaving
12.7 g (87 percent) of a white crystalline powder. The material
was shown to be 1-hydroxycyclohexyl 4-(2-
carboxyethyl)carbonylphenyl ketone by nuclear magnetic
resonance analysis.
95/04955 PCT/US94/08588
- 31 - 2163727
B . Preparation of Acvlated Transorher Acid Chloride
A 250-ml round-bottomed flask fitted with a
condenser was charged with 12.0 g of l-hydroxycyclohexyl 4-(2-
carboxyethyl)carbonylphenyl ketone (0.04 mole), 5.95 g (0.05
mole) of thionyl chloride (Aldrich), and 50 ml of diethyl ether.
The resulting reaction mixture was stirred at 30C for 30
minutes, after which time the solvent was removed under reduced
pressure. The residue, a white solid, was m~int~ined at 0.01 Torr
for 30 minutes to remove residual solvent and excess thionyl
chloride, leaving 12.1 g (94 percent) of l-hydroxycyclohexyl 4-
(2-chloroformylethyl)carbonylphenyl ketone.
C. Covalent Bonding of Acylated Transorber to Cvclode~trin
A 250-ml, three-necked, round-bottomed reaction
flask containing a magnetic stirring bar and fitted with a
therrnometer, condenser, and pressure-eqll~li7ing addition funnel
equipped with a nitrogen inlet tube was charged with 10 g (9.8
~nmole) of ~-cyclodextrin (American Maize-Products Company,
Hamrnond, Indiana), 31.6 g (98 mmoles) of 1-hydroxycyclohexyl
4-(2-chloroformylethyl)carbonylphenyl ketone, and 100 ml of
N,N-dimethylformamide while being continuously flushed with
nitrogen. The reaction mixture-was heated to 50C and 0.5 ml of
triethylamine added. The reaction mixture was m~int~ined at
50C for an hour and allowed to cool to ambient temperature. In
this preparation, no attempt was made to isolate the product, a
~-cyclodextrin to which an ultraviolet radiation transorber had
been covalently coupled (referred to hereinafter for convenience
as J3-cyclodextrin-transorber).
The foregoing procedure was repeated to isolate the
product of the reaction. At the conclusion of the procedure as
described, the reaction mixture was concentrated in a rotary
evaporator to roughly 10 percent of the original volurne. The
residue was poured into ice water to which sodium chloride then
was added to force the product out of solution. The resulting
precipitate was isolated by filtration and washed with diethyl
95/04955 PCT/US94/08588
32
2 1 g~ ~ 7 2 ~
ether. The solid was dried under reduced pressure to give 24.8 g
of a white powder. In a third preparation, the residue rem~ining
in the rotary evaporator was placed on top of an approximately
7.5-cm column cont~ininP about 15 g of silica gel. The residue
S was eluted with N,N-dimethylfonn~mide, with the eluant being
monitored by means of Wh~tm~n~ Flexible-Backed TLC Plates
(Catalog No. 05-713-161, Fisher Scientific, Pittsburgh,
Pennsylvania). The eluted product was isolated by evaporating
the solvent. The structure of the product was verified by nuclear
magnetic resonance analysis.
D. Association of Colorant with C~clodextrin-Transorher-
Preparation of Colored Composition
To a solution of 10 g (estimated to be about 3.6
mmole) of beta-cyclodextrin-transorber in 150 ml of N,N-
dimethylforrn~mide in a 250-ml round-bottomed flask was added
at ambient temperature 1.2 g (3.6 mmole) of Malachite Green
oxalate (Aldrich Chemical Company, Inc., Milwaukee,
Wisconsin), referred to hereinafter as Colorant A for
convenience. The reaction mixture was stirred with a magnetic
stirring bar for one hour at ambient temperature. Most of the
solvent then was removed in a rotary evaporator and the residue
was eluted from a silica gel column as already described. The
beta-cyclode~trin-transorber Colorant A inclusion complex
moved down the column first, cleanly separating from both free
Colorant A and beta-cyclodextrin-transorber. The eluant
collt~ the complex was collected and the solvent removed in a
rotary evaporator. The residue was subjected to a reduced
pressure of 0.01 Torr to remove residual solvent to yield a blue-
green powder.
E. Mutation of Colored Composition
The beta-cyclodextrin-transorber Colorant A
inclusion complex was exposed to ultraviolet radiation from two
different lamps, Lamps A and B. Lamp A was a 222-nanometer
- 95/04955 PCT/US94/08588
- 33 -
2168727
excimer lamp assembly organized in banks of four cylindrical
lamps having a length of about 30 cm. The lamps were cooled by
circulating water through a centrally located or inner tube of the
lamp and, as a consequence, they operated at a relatively low
temperature, i.e., about 50C. The power density at the lamp's
outer surface typically is in the range of from about 4 to about 20
joules per square meter (J/m2). However, such range in reality
merely reflects the capabilities of current excimer lamp power
supplies; in the future, higher power densities may be practical.
The distance from the lamp to the sample being irr~ terl was 4.5
cm. Lamp B was a 500-watt Hanovia medium pressure mercury
lamp (Hanovia Lamp Co., Newark, New Jersey). The distance
from Lamp B to the sample being irradiated was about 15 cm.
A few drops of an N,N-dimethylformamide solution
of the beta-cyclodextrin-transorber Colorant A inclusion complex
were placed on a TLC plate and in a small polyethylene weighing
pan. Both samples were exposed to Lamp A and were
decolorized (mutated to a colorless state) in 15-20 seconds.
Similar results were obtained with Lamp B in 30 seconds.
A first control sample consisting of a solution of
Colorant A and beta-cyclodextrin in N,N-dimethylformamide was
not decolorized by Lamp A. A second control sample consisting
of Colorant A and l-hydroxycyclohexyl phenyl ketone in N,N-
dimethylformamide was decolorized by Lamp A within 60
seconds. On standing, however, the color began to reappear
within an hour.
To evaluate the effect of solvent on decolorization,
50 mg of the beta-cyclodextrin-transorber Colorant A inclusion
complex was dissolved in 1 ml of solvent. The resulting solution
or mixture was placed on a glass microscope slide and exposed to
Lamp A for 1 minllte. The rate of decolorization, i.e., the time to
render the sample colorless, was directly proportional to the
solubility of the complex in the solvent, as sllmm~rized below.
~ 95104955 PCT/US94t08588
- 34 - 216~727
Solvent Solubility Decolorization
Time
N,N-Dimethylformamide Poor 1 minute
Dimethylsulfoxide Soluble <10 seconds
Acetone ~ Soluble ~10 seconds
Hexane Insoluble --
Ethyl Acetate Poor l minute
Finally, 10 mg of the beta-cyclodextrin-transorber
Colorant A inclusion complex were placed on a glass microscope
slide and crushed with a pestle. The resulting powder was exposed
to Lamp A for 10 seconds. The powder tumed colorless. Similar
results were obtained with lamp B, but at a slower rate.
EXAMPLE 4
Because of the possibility in the preparation of
colored composition described in Example 3 for the acylated
transorber acid chloride to at least partially occupy the cavity of
the cyclodextrin, to the partial or complete exclusion of colorant,
a modified preparative procedure was carried out. Thus, this
example describes the preparation of a beta-cyclodextrin
molecular includant having (1) a colorant at least partially
included within the cavity of the cyclodextrin and associated
therewith by means of hydrogen bonds and/or van der Waals
forces and (2) an ultraviolet radiation transorber covalently
bonded to the cyclodextrin outside of the cavity of the
cyclodextrin.
A. Association of Colorant with a Cvclodextrin
To a solution of 10.0 g (9.8 mmole) of beta-
cyclodextrin in 150 ml of N,N-dimethylformamide was added
3.24 g (9.6 mmoles) of Colorant A. The resulting solution was
stirred at ambient temperature for one hour. The reaction
solution was concentrated under reduced pressure in a rotary
95/04955 PCT/US94/08588
- 35 - 21~727
evaporator to a volume about one-tenth of the original volume.
The residue was passed over a silica gel column as described in
Part C of Example 1. The solvent in the eluant was removed
under reduced pressure in a rotary evaporator to give 12.4 g of a
blue-green powder, beta-cyclodextrin Colorant A inclusion
complex.
B. Covalent Bonding of Acvlated Transorber to Cvclodextrin
Colorant Inclusion Complex - Preparation of Colored
Composition
A 250-ml, three-necked. round-bottomed reaction
flask containing a magnetic stirring bar and fitted with a
thermometer, condenser, and pressure-eqll~li7.ing addition funnel
equipped with a nitrogen inlet tube was charged with 10 g (9.6
mmole) of beta-cyclodextrin Colorant A inclusion complex, 31.6
g (98 mmoles) of 1-hydroxycyclohexyl
4-(2-chloroformylethyl)carbonylphenyl ketone prepared as
described in Part B of Example 1, and 150 ml of
N,N-dimethylformamide while being continuously flushed with
nitrogen. The reaction mixture was heated to 50C and 0.5 ml of
triethylamine added. The reaction mixture was m~int~ined at
50C for an hour and allowed to cool to ambient temperature.
The reaction mixture then was worked up as described in Part A,
above, to give 14.2 g of beta-cyclodextrin-transorber Colorant A
inclusion complex. a blue-green powder.
C. Mutation of Colored Composition
The procedures described in Part E of Example 1
were repeated with the beta-cyclodextrin-transorber Colorant A
inclusion complex prepared in part B, above, with essentially the
same results.
~ 95/04g55 Pcrruss4/ossss
- 36 - 216~727
EXAMPLE 5
This Example describes a method of preparing an
ultraviolet radiation transorber designated phthaloylglycine-2959.
The following was- admixed in a 250ml 3-necked round
bottomed flask fitted with a Dean & Stark adapter with condenser
and two glass stoppers: 20.5g (O.lmole) of the wavelength
selective sensitizer, phthaloylglycine (Aldrich); 24.6g (O.lmole)
of the photoreactor, DARCUR 2959 (Ciba-Geigy, Hawthorne,
NY); 100 ml of benzene (Aldrich); and 0.4g p-toluene sulfonic
acid (Aldrich). The mixture was heated at reflux for 3 hours
after which time 1.8 ml of water was collected. The solvent was
removed under reduced pressure to give 43.1g of white powder.
The powder was recrystallized from 30% ethyl acetate in hexane
(Fisher) to yield 40.2g (93~o) of a white crystalline powder
having a melting point of 153-4C. The reaction is s-lmm~rized
as follows
[~N--CH,CO2H + HO--(CH2)2--(~ CH
o p-toluene
sulfonic acid
Benzene
~N--CH,C--O(CH.),O~ CH3
The resulting product, designated phthaloyl glycine-2959, had the
following physical parameters:
IR [Nujol Muu] ] vma,~ 3440, 1760, 1740, 1680, 1600 cm-
- gs/o4sss PCT/USs4/08588
~ 37 ~ 216~727
IHNMR [CDCL3] appm 1.64[s], 4.25[m], 4.49[m], 6.92[m],
7.25[m], 7.86[m], 7.98[m], 8.06[m] ppm
EXAMPLE 6
This Example describes a method of dehydrating the
phthaloylglycine-2959 produced in Exarnple 5.
The following was admixed in a 250ml round bottomed
flask fitted with a Dean & Stark adaptor with condenser: 21.6g
(0.05 mole) phthaltoylglycine-2959; 100~n1 of anhydrous benzene
(Aldrich); and 0.1 g p-toulene sulfonic acid (Aldrich). The
mixture was refluxed for 3 hours. After 0.7ml of water had been
collected in the trap, the solution was then removed under vacuurn
to yield 20.1g (97%) of a white solid. The solid was used without
further purification. The reaction is sllmm~rized as follows:
~ N--CH2C--O(CH2). ~COI _c\CcHo33H
p-toluene
sulfonic acid
Benzene
~N--CH2C--o(CH2)20~3lol lCH.
The
resulting reaction product had the following physical parameters:
IR (NUJOL) vma~ 1617cm-l (C=C=O)
~ 95/W955 PCT/US94108588
- 3~3 - 21~372~
EXAMPLE 7
This Example describes a method of producing a beta-
cyclodextrin having dehydrated phthaloylglycine-2959 groups
from Example 6 covalently bonded thereto.
The following was admixed in a 100ml round bottomed
Flask: 5.0g (4mmole) beta-cyclodextrin (American Maize
Product Company, Hammond, In~ n~) (designated beta-CD in the
following reaction); 8.3g (20 mmole) dehydrated
phthaloylglycine-2959; 50ml of anhydrous DMF; 20ml of
benzene; and O.Olg p-tolulenesulfonyl chloride (Aldrich). The
mixture was chilled in a salt/ice bath and stirred for 24 hours.
The reaction mixture was poured into l50ml of weak sodium
bicarbonate solution and extracted three times with 50ml ethyl
ether. The aqeuous layer was then filtered to yield a white solid
comprising the beta-cyclodextrin with phthaloylglycine-2959
group attached. A yield of 9.4g was obtained. Reverse phase
TLC plate using a 50:50 DMF:acetonitrile mixture showed a new
product peak compared to the starting materials.
Beta-CD
[~N--CH"C--O(CH,) ,O~ CH, ~_
HO--CH2CH~
Beta-CD
o
~ 11 ~CH~--O--CH~CH2/
~N--CH2C--O(CH2)2--~=~C CH3
o
95/04955 PCT/US94/08588
- 39 - 2163727
Of course, the beta-cyclodextrin molecule has several
primary alcohols and secondary alcohols with which the
phthaloylglycine-2959 can react. The above representative
reaction only shows a single phthaloylglycine-2959 molecule for
illustrative purposes.
EXAMPLE 8
This example describes a method of associating a colorant
and an ultraviolet radiation transorber with a molecular includant.
More par~icularly, this Example describes a method of associating
the colorant crystal violet with the molecular includant beta-
cyclodextrin covalently bonded to the ultraviolet radiation
transorber phthaloylglycine-2959 of Example 7.
The following was placed in a lOOml beaker: 4.0 g beta-
cyclodextrin having a dehydrated phthaloylglycine-2959 group;
and 50ml of water. The water was heated to 70C at which point
the solution became clear. Next, O.9g (2.4 mmole) crystal violet
(Aldrich Chemical Company, Milwaukee, WI) was added to the
solution, and the solution was stirred for 20 minutes. Next, the
solution was then filtered. The filtrand was washed with the
filtrate and then dried in a vacuum oven at 84C. A violet-blue
powder was obtained having 4.1g (92%) yield. The resulting
reaction product had the folowing physical pararneters:
U.V. Spectrurn DMF ~maX 610nm (cf cv AmaX 604nm)
EXAMPLE 9
This Example describes a method of producing the
ultraviolet radiation transorber 4~4-hydroxyphenyl) butan-2-one-
2959 (chloro substituted) .
The following was admixed in a 250ml round bottomed
flask fitted with a condensor and magnetic stir bar: 17.6g
(O.lmole) of the wavelength selective sensitizer, 4(4-
95to49~;5 PCT/US94/08588
- 40 -
216~727
hydroxyphenyl) butan-2-one (Aldrich Chemical Company,
Milwaukee, WI); 26.4g (0.1 mole) of the photoreactor, chloro
substituted DARCUR 2959 (Ciba-Geigy Colporation, Hawthorne, .-
New York); 1.0 ml of pyridine (Aldrich Chemical Company,
Milwaukee, WI); and 1 OOml of anhydrous tetrahydrofuran
(Aldrich Chemical Company, Milwaukee, W~). The mixture was
refluxed for 3 hours and the solvent partially removed under
reduced pressure (60% taken off). The reaction mixture was then
poured into ice water and extracted with two 50ml aliquots of
diethyl ether. After drying over anhydrous magnesium sulfate
and removal of solvent, 39.1 g of white solvent remained.
Recrystallization of the powder from 30% ethyl acetate in hexane
gave 36.7g (91%) of a white crystalline powder, having a melting
point of 142-3C. The reaction is sl-mm~rized in the following
reaction:
CH3--C--CH ,CH~ ~IH + Cl(CH~)2--G~311 ,CH3
CH3--C--CH~CH~ ~(CH~ OH
The resulting reaction product had the folowing physical
parameters:
IR [Nujol Muu] vma,~ 3460, 1760, 1700, 1620, 1600 cm-
lH [CDCL3] ~ppm 1.62[s], 4.2[m], 4.5[m], 6.9[m] ppm
The ultraviolet radiation transorber produced in this
Example, 4(4-hydroxyphenyl) butan-2-one-2959 (chloro
substituted), may be associtated with beta-cyclodextrin and a
colorant such as crystal violet, using the methods described above
in E,~a.mples 6 through 8 wherein 4(4-hydroxyphenyl~ buta.n-2.-
) 95/04955 PCT/US94/08588
216~727
one-2959 (chloro substituted) would be substituted for the
dehydrated phthaloylglycine-2959 in the methods in Examples 6
through 8.
EXAMPLE 10
This Example demonstrates that the 222 nanometer excimer
lamps illustrated in Figure 3 produce uniform intensity readings
on a surface of a substrate 5.5 centimeters from the lamps, at the
numbered locations, in an amount sufficient to mutate the colorant
in the compositions of the present invention which are present on
the surface of the substrate. The lamp 10 comprises a lamp
housing 15 with four excimer lamp bulbs 20 positioned in
parallel, the excimer lamp bulbs 20 are approximately 30 cm in
length. The lamps are cooled by circulating water through a
centrally located or inner tube (not shown) and, as a consequence,
the lamps are operated at a relatively low temperature, i.e., about
50C. The power density at the lamp's outer surface typically is
in the range of from about 4 to about 20 joules per square
meter (J/m2).
Table 5 sllmm~rizes the intensity readings which were
obtained by a meter located on the surface of the substrate. The
readings numbered 1, 4, 7, and 10 were located approximately
7.0 centimeters from the left end of the column as shown in
Figure 3. The re~lin~ numbered 3, 6, 9, and 12 were located
appro~im~tely 5.5 centimeters from the right end of the column
as shown in Figure 3. The readings numbered 2, 5, 8, and 11
were centrally located approximately 17.5 centirneters from each
end of the column as shown in Figure 3.
95~04955 PCT/US94/08588
- 12 - 2 1 6~ 7 2 7
TABLE 5
Back~round (~W) Reading (mW/cm2)
24.57 9.63
19.56 - 9.35
22.67 9.39
19.62 9.33
17.90 9.30
19.60 9.30
21.41 9.32
17.91 9.30
23.49 9.30
19.15 9.36
17.12 9.35
21.44 9.37
F,XAMPT,F, 11
This Example demonstrates that the 222 nanometer excimer
lamps illustrated in Figure 4 produce unifollll intensity readings
on a surface of a substrate S.S centimeters from the lamps, at the
numbered locations, in an amount sufficient to mutate the colorant
in the compositions of the present invention which are present on
the surface of the substrate. The excimer lamp 10 comprises a
lamp housing 15 with four excimer lamp bulbs 20 positioned in
parallel, the excimer lamp bulbs 20 are approximately 30 cm in
lS length. The lamps are cooled by circulating water through a
centrally located or inner tube (not shown) and, as a consequence,
the lamps are operated at a relatively low temperature, i.e., about
50C. The power density at the lamp's outer surface typically is
in the range of from about 4 to about 20 joules per square meter
(J/m2).
Table 6 sl-mm~rizes the intensity readings which were
obtained by a meter located on the surface of the substrate. The
` 9~/04955 PCT/US94/08588
- 43 - 216~727
readings numbered 1, 4, and 7 were located approximately 7.0
centimeters from the left end of the columns as shown in Figure
4. The readings numbered 3, 6, and 9 were located
approximately 5.5 centimeters from the right end of the columns
S as shown in Figure 4. The re~lin~.s numbered 2, 5, 8 were
centrally located approximately 17.5 centimeters from each end
of the columns as shown in Figure 4.
TABLE 6
Back~round (uW) Readin~ (mW/cm~
23.46 9.32
16.12 9.31
17.39 9.32
20.19 9.31
16.45 9.29
20.42 9.31
18.33 9.32
15.50 9.30
20.90 9.34
FXAMp~,F, l?
This Example demonstrates the intensity produced by the
lS 222 nanometer excimer lamps illustrated in Figure 5, on a surface
of a substrate, as a function of the tli.st~nce of the surface from the
lamps, the intensity being sufficient to mllt~te the colorant in the
compositions of the present invention which are present on the
surface of the substrate. The excimer lamp 10 comprises a lamp
housing 15 with four excimer lamp bulbs 20 positioned in
parallel, the excimer lamp bulbs 20 are approxim~tely 30 cm in
length. The lamps are cooled by circulating water through a
centrally located or inner tube (not shown) and, as a consequence,
the lamps are operated at a relatively low temperature, i.e., about
50C. The power density at the lamp's outer surface typically is
95~04955 PCT/US94/08588
-44- 216~727
in the range of from about 4 to about 20 joules per square meter
(Jlm2).
Table 7 sl-mm~rizes the intensity readings which were
obtained by a meter located on the surface of the substrate at
S position 1 as shown in Figure 5. Position 1 was centrally located
approximately 17 centimeters from each end of the column as
shown in Figure 5.
TABLE 7
Distance Back~round Readin~
(cm) (~W) (mW/cm~
5.5 18.85 9.30
6.0 15.78 9.32
18.60 9.32
20.90 9.38
21.67 9.48
19.86 9.69
22.50 11.14
26.28 9.10
24.71 7.58
26.95 5.20
Having thus described the invention, numerous
changes and modifications hereof will be readily apparent to those
having ordinary skill in the art without departing from the spirit
or scope of the invention.
