Note: Descriptions are shown in the official language in which they were submitted.
CA 02092232 2000-OS-04
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LATENT IMAGE RECEIVING SHEET
Background of the Invention
1. Field of Invention
This invention relates to record material. It more
particularly relates to image receiving sheets in the form of
sheets and adhered microcapsules.
2. Description of Related Art
Record material systems are well known in the art and
are described in many patents, for example, U.S. Patent Nos.
3,539,375; 3,674,535; 3,746,675; 4,151,748; 4,181,771;
4,246,318; and 4,470,057. In thermally responsive systems,
basic chromogenic material and acidic color developer material
are contained in a coating on a substrate which, when heated to
a suitable temperature, melts or softens to permit said
materials to react, thereby producing a colored mark.
1
J
U.S. Patent No. 4,529,681 discloses a light- and heat-sensitive record
material relying
on use of permeable capsules relying on heat to effect coloring component
permeation
through the thermoplastic capsule wall.
It is an object of the present invention to disclose an image receiving sheet.
Detaila:d Description
The present invention is a novel nonmeltable microcapsule and resulting latent
image
receiving sheet. This sheet with microcapsules is useful to form a variety of
useful products
including:
a) an ink 'transfer sheet or print plate.
In this embodiment, the microcapsules contain a dye, ink, pigment, or dye
precursor.
The latent image is recorded by means of application of a point source energy
input or pulse
comprising a eT of at least 115~C per one millisecond. The sheet is then
pressed against a
second sheet resulting in transfer of a visible image corresponding to the
capsules on the
latent image sheet which had been ruptured by the point source energy pulse.
Sublimable dyes
can be used in a variation and the latent image transferred after capsule
rupture by heating
the latent image sheet to effect transfer of dyes to a second sheet.
b) a low cost gravure type of sheet.
In this embodiment, the microcapsules contain a low boiling or a high vapor
pressure
solvent, or a gas. The latent image receiving sheet when exposed to a point
source energy
input or pulse comprising a eT of at least 115oC per one millisecond results
in a sheet with
a selected field of ruptured capsules. The ruptured capsules define the latent
image. Over
-z-
time the contents of the ruptured capsules evaporate, leaving a low cost
gravure type of sheet.
An ink can be squeegeed over the sheet to fill the voids created by the
ruptured capsules. A
second sheet can then be pressed against the latent image receiving sheet to
effect transfer of
an image corresponding to the ruptured capsules.
c) a cryptic message receiving sheet.
Tn this embodiment, the microcapsules, similar to b) above, contain a low
boiling or
high vapor pressure solvent, or a gas. The latent image receiving sheet when
exposed to a
point source energy input or pulse comprising a eT of at least 115°C
per one millisecond
results in a sheet with a selected field of ruptured capsules. As in b) above,
this selected field
constitutes a latent image in that selection can be in a predetermined
pattern. The image can
be developed by application of toner fine particles, such as xerographic
toners, onto the sheet.
These will preferentially adhere to the nrptured capsule sites.
d) an imageable sheet.
In this embodiment, the microcapsules contain one of either a chromogen ax
developer.
The latent image receiving sheet when exposed to a point source energy input
or pulse
comprising eT of at least 115°C per one millisecond results in a sheet
with a selected field
or pattern of ruptured capsules. The ruptured capsules define a latent image.
The image can
be made visible by application to the latent image receiving sheet of a
solvent or dispersion
containing the second component of chromogen or developer, whichevex was
omitted from
the capsule contents.
The invention will now be more fully described with a pa~rticulur focus on the
novel
capsules of the invention.
-3-
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The latent image receiving sheet of the invention comprises a
substrate bearing microcapsules having walls selected from non-
meltable or thermoset resin. The walls of the microcapsules
are selected to have an elongation not more than lo.
Surprisingly, the non-meltable walls of the microcapsules
rupture upon application thereto of a point source energy input
comprising a 0T of at least 115°C per one millisecond.
The latent image receiving sheet has adhered
microcapsules having walls of thermosetting or non-meltable
resin with critically an elongation of not more than 1~. The
thermosetting resin is preferably selected from methylated
methylol melamine, methylol melamine dimethylol urea, and
methylated dimethylol urea. When methylol melamine is
employed, preferably it is polymerized at a temperature of at
least 65°C; and in place of previously prepared methylol
melamine, it may be prepared in situ from melamine and
formaldehyde. When dimethylol urea is employed, in place of
previously prepared dimethyl urea, it may be prepared in situ
from urea and formaldehyde. When dimethylol urea or its
methylated derivative, i.e., methylated dimethylol urea, a
molar ratio of formaldehyde to urea is preferably from 1.9 to
2.1. Table 1 lists elongations of a variety of resins. A
portion of the urea can be replaced by a hydroxy-substituted
phenol, such as resorcinol. The microcapsule walls are
nonmeltable.
The microcapsules are preferably prepared by a
process in an aqueous manufacturing vehicle. The process
comprises enwrapping an intended capsule core material
substantially insoluble in the vehicle with a polymeric wall
produced by in situ polymerization of the thermosetting resin.
When methylol melamine or dimethylol urea is the thermosetting
4
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resin, the in situ polymerization may be combined with the in
situ preparation of the resin from a combination of melamine
and formaldehyde or a combination of urea and formaldehyde.
4a
Exposure of the latent image receiving sheet to a point source energy input
comprising
a eT ("change in temperature") of at least l I5°C per one millisecond
ruptures the capsules
and this is theorized to occur due to induced or produced stresses.
The microcapsules can contain any core material conventionally used in
S microencapsulation. These can include various combinations of a solvent, a
hydrophobic or
hydrophillic material, liquid preferably hydrophobic liquid, gas, developer or
chromogen,
inks, dyes, toners, or pigments.
The novel sheet with microcapsules of the invention has a variety of new uses.
Upon
exposure of the sheet with microcapsules to a point source energy input
comprising a eT
1U ("change in temperature") of at least 115°C per one millisecond, the
microcapsules nipture.
Though the microcapsule and sheet material characteristics are described in
terms of
a point source energy input such as a thermal print head, it is readily
apparent and understood
that such record material or image receiving sheet can be imaged with a larger
input device
such as a rapidly heating block or multiplicity of thermal print heads
assembled as a larger
15 unit. Point sources for purposes of the invention can take the form of a
thermal print head,
laser, focussed hot jets, heated stylus and the like. The ability to effect a
change in
temperature of at least 115nC per one millisecond at the receiving sheet's
surface is needed
to effect the unusual shattering of the non-meltable capsules of the
invention. Shattering is
believed attributable to induced or produced thermal stresses though the
invention disclosed
20 herein should not be construed as limited to this one underlying theory, as
other mechanisms
may also be operating.
-5-
Upon application of the appropriate eT to the sheet in a selective pattern, a
latent
image is recorded on the sheet by virtue of rupture of tlae microcapsules,
which one can think
of in terms of an assembly of sealed bottles, some of which, however, tu~e
selectively
shattered so that they have open tops, thus becoming open containers. An
appropriate
developer material can be applied across the surface of the sheet by
conventional applicator
means such as sponging, spraying, cotton swab or other applicator to develop
the image.
Alternatively, if a hydrophobic material is placed in the capsule, a
hydrophobic ink or dye
applied across the surface of the sheet will, preferentially, adhere to the
hydrophobic material
resulting in an image.
The capsules of the latent image receiving sheet, unlike the prior art, do not
melt or
become porous, but rather fracture from the rapid change in temperature or
energy input.
If the microcapsules are constn~cted such as to encapsulate a hydrophobic
material,
then after recording a latent image on the receiving sheet with a thermal
print head, a
hydrophobic ink can be applied across the surface of the sheet, and it will
preferentially
occupy the capsules with shattered tops exposing hydrophobic material when the
freely
applied hydrophobic ink is squeegeed or dviped away from the surface of the
sheet.
Conversely, hydrophillic materials can be encapsulated for use with
hydrophillic inks. The
result is a, low-cost gravure type of print plate or transfer sheet.
Alternatively, ink or dye can
be encapsulated in the capsules to also create a similar transfer sheet.
If use as a print plate is contemplated, then the substrate is typically
selected of morn
rigid stock or even synthetic material for better durability.
The latent image receiving sheet can be used as optical recording medium, such
as for
recording of digitized information by laser or thermal print head.
-6-
The latent image receiving sheet also finds use for transfer of information in
latent
form. Being created by a thermal print head, transmission of cryptic messages
is made
possible. The latent image can be subsequently developed as herein earlier
described.
The capsules of the receiving sheet, unlike the prior art, do not melt or
become porous
S upon energy input, but rather fracture from the rapid change in temperature
or energy input
such as an energy pulse. L:xposure of the receiving slzeet to an energy input,
such. as with a
thermal print head, or other source capable of generating the appropriate nT
shatters the
microcapsules and encodes the latent image.
The capsules of the record material, unlike the prior art, do not melt upon
energy
input, but rather appear to rupture from rapid change in temperature or energy
input.
Significantly this gives rise to a novel material which is heat resistant.
Surprisingly the latent
image receiving sheet of the invention can be placed in a hot oven
(150°C) for substantial
time periods such as one minute and the capsules do not become permeable.
Conventional
thermal paper by contrast images in an oven almost instantaneously.
The insulating characteristics of the wall material and the absence of heat
dissipation
via phase change appe~us to lead to a high concentration of energy at the
contact area
between the point source and the capsule.
The elongation value for the wall material of the microcapsules can be token
from
tables for various resins. The published values correlated well with the
observed phenomena
and provide a convenient means to select appropriate resins. Resins having
elongation values
of not more than 1% selected to be used as wall material result in
microcapsules with
nonmeltable polymeric shells or wall material displaying the unusual
characteristics of
shattering attributable to induced thermal stresses.
Table 1 summarizes elongation values for a variety of resin materials.
_7_
TABLE 1
Resin Elongation
(%)
acetal 60-75
acrylic 20-50
cellulose 5-100
fluorcarb 80-400
ionomers 100-600
polyamides 25-300
polycarbonates 60-100
polyethylenes 5-900
polypropylenes 3-700
polystyrenes 1-140
vinyls 2-400
epoxies 1-70
phenolics 1-2
phenol formaldehyde 0.4-2
melamine formaldehyde 0.6-1.0
polyester 40-300
polyester alkyd U.5-2
silicone 100
urea formaldehyde 0.5
urethane 300-1000
nylon 300
-8-
.,
The elongation of the polymeric shells or wall is determined for purposes of
the
invention, from the elongation (%) value of the bulk resins when polymerized
wand using
Standards tests SUCIt as ASTIvI test method DG38.
More conveniently, tables of elongation (%) values for a variety of resins are
available
from a variety of sources including pages 532 to 537 of Principles of Polymer
Systems, 2nd
Edition by Ferdinand Rodriguez of Cornell University, published by 1-
lemisphere Publishing
Corporation (1970). The elongation values for the bulk material correlated
well as a surprising
predictor of resins functional in the invention.
Instead of melting, becoming plasticized with other melted materials, or
increasing in
permeability due to a phase tz~ansformation, the wall of the capsules of the
invention appears
to rupture. Failure of the capsule wall appears attributed to a high
temperature gradient and
nonsteady state of heat transfer. Such conditions create localized thermal
stresses. The
magnitude of the st~~ess depends on the properties of the material. A brittle
wall can sustain
less strain and thus ruptures.
Elongation properties appear to correlate well with wall brittleness and
facilitate
selection of resin.
The capsules of the invention surprisingly fracture upon application of a
point source
energy input comprising a change in temperature (eT) of at least llSoC per one
millisecond.
eT can be calctrlatcd according to the formula
S = E a (T - To)
_9_
~~~~~J~
S refers to stress
E is modules of elasticity
a is coefficient of linear thermal expansion
eT is T-To in the above formula. S which is stress ranges for melamine
formaldehyde polymers from 5x10' psi to 13x10' psi and for phenol formaldehyde
polymers
ranges from about 5x10' psi to about 9x10' psi. To calculate the lower
practical point source
energy input S is taken as (5x10') psi. The modules of elasticity ranges from
about (11x105)
to (14x105) psi. On tl~e lower range thus, E is taken as 11x105. The
coefficient of linear
thermal expansion is (4x10-5)~C.
Therefore, 5x10' = (11x10j) (4x10'5) (T-To)
(T-To) = eT = 113.6° or about 115°C per one millisecond.
By this method the calculated threshold eT is about 115~C.
A second method of arriving at eT is by way of the data derived from Example
1.
Example 1 demonstrates that the temperature at the record system surface when
using a
-15 conventional fax such as a Canon Fax 230 is greater than 170~C. This is
the temperature that
the surface of the paper or media sees. The temperature of the thermal print
head is higher,
but the temperature observed at the surface of the media is alone relevant as
regards the
thermal stresses to which the capsules on the surface of the paper are
subjected.
Room temperature is approximately 25pC and thus should be substracted from the
temperature measured, 170°C - 25~C = 145°C. Based on the
quantity of dye present, dT
to effect fracture was calculated as approximately at least 115~C per one
mitlisecond but
preferably 1450C per one millisecond.
Since the capsules are nonmeltable or thermoset in character, there is no
latent heat
capacity and substantially no phase change.
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In the examples, the record system when subjected to
a thermal print head, resulted in ruptured capsules observed
with a scanning electron microscope.
The capsule core material can include inks, dyes,
toners, chromogens, solvents, gases, liquids, and pigments.
The capsule core material is relatively independently selected.
The core can be any material which is substantially water
insoluble. Extensive lists of other core materials are listed
in U.S. Patent 4,001,140. The core material can be any
material dispersible in water and wrappable by the wall
material. This can include air. As a more specific
description of a useful core material, an imaging material such
as chromogen, dye, toner, or pigment and the like can be
prepositioned in the microcapsules as the core material. The
core can be selected to be colorless electron donating
compounds, dye precursor or chromogens which form color by
reacting with a developer material. Representative examples of
such compounds include substantially colorless compounds having
a lactone, a lactam, a sulfone, a spiropyran, an ester or an
amido structure in their partial skeleton such as trirylmethane
compounds, bisphenylmethane compounds, xanthene compounds,
fluorans, thiazine compounds, spiropyran compounds and the
like.
Eligible electron donating dye precursors which are
chromogenic compounds, such as the phthalide, leucauramine and
fluoran compounds, for use in the color-forming system are well
known. Examples of the chromogens include Crystal Violet
Lactone (3,3-bis(4-dimethylaminophenyl)-6-
dimethylaminophthalide, U.S. Patent No. Re. 23,024); phenyl-,
indol-, pyrrol-, and carbazol-substituted phthalides (for
example, in U.S. Patent Nos. 3,491,111; 3,491,112; 3,491,116;
3,509,174); nitro-, amino-, amido-, sulfon amido-,
aminobenzylidene-, halo-, anilino-substituted fluorans (for
11
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69601-96
example, in U.S. Patent Nos. 3,624,107; 3,627,787; 3,641,011;
3,642,828; 3,681,390); spiro- dipyrans U.S. Patent No.
3,971,808); and pyridine and pyrazine compounds (for example,
in U.S. Patent Nos. 3,775,424
lla
i~~ ~t ~~~
3,971,808); and pyridine and pyrazine compounds (for example, in U.S. Patent
Nos. 3,775,424
and 3,853,869). Other specilically eligible chromogenic compounds, not
limiting the invention
in any way, are: 3-diethylamino-6-methyl-7-anilino-fluoran (U.S. Patent No.
3,681,390); 2-
anilino-3-methyl-6-dibutylamino-fluoran (U.S. Patent 4,510,513) also known as
3-
dibutylamino-6-methyl-7-anilino-fluoran; 3-clibutylamina-7-(2-chloroanilino)
fluoran; 3-(N-
ethyl-N-tetrahydrofurfurylamino)-6-methyl-7-3-5'6-iris(di-
methylamino)spiro[9II-fluorene-
9'1(3'II)-isobenzofuran]-3'-one; 7-(1-ethyl-2-methylindol-3-yl)-7-(4-
diethylamino-2-
ethoxyphenyl)-5,7-dihydrofuro[3,4-b]pyridin-5-one(U.S. Patent No. 4,246.,318);
3-
cliethylamino-7-(2-chloroanilino)fluoran (U.S. Patent No. 3,920,510); 3-(N-
methylcyclohexylamino)-6-methyl-7-anilino-fluoran (U.S. Patent No. 3,959,71);
7-(1-octyl-2-
methylindol-3-yl)-7-(4-diethylamino-2-ethaxyphenyl) -5,7-clihydrofuro[3,4-b]
pyridin-5-one;
3-diethylamino-7, 8-benzofluoran; 3, 3-bis(1-ethyl-2-methylindol-3-yl)
phthalide; 3-
diethylamino-7-anilinofluoran; 3-diethylamino-7-benzylamino-fluoran; 3'-phenyl-
7-
dibenzylamino-2,2'-spiro-di-[2II-1-benzo-pyrun] and mixtures of any of the
following.
Solvents such as the following can optionally be included in the
microcapsules:
1. Dialkyl phthalates in which the alkyl groups thereof have from 4 to 13
carbon
atoms, e.g., clibutyl phthalate, dioctylphthalate, dinonyl phthalate and
ditridecyl
phthalate
2. 2,2,4-ti~imethyl-1,3-pentanediol diisobutyrate (U.S. Patent No. 4,027,065)
3. ethyldiphenylmethane (U.S. Patent No. 3,996,405)
4. alkyl biphenyls such us monoisopropylbiphenyl (U.S. Patent No. 3,627,581)
5. C,o C,4 alkyl benzenes such as dodecyl benzene
6. diaryl ethers, di(aralkyl)ethers and aryl aralkyl ethers, ethers such as
Biphenyl
ether, dibenzyl ether and phenyl benzyl ether
-12-
~~~~~J~
7. liquid hither clialkyl ethers (having at least 8 carbon atoms)
8. liduid higher alkyl ketones (having at least 9 carbon atoms)
9. alkyl or aralkyl benzoates, e.g., benzyl benzoate
10. alkylated naphthalenes
11. partially hydrogenated terphenyls
The solvent, if included, can be selected to facilitate dissolving the dye
mixture, if
included. If the capsules include chrornogens, the latent image of the
receiving sheet can be
made visible by various conventional acidic developer materials preferably as
dispersions or
solutions applied to the latent image receiving sheet following application of
the latent image.
Other variations can include prepositioning the acidic developer material in
substantially
contiguous relationship to the chromogen material. Developer can be positioned
in the
capsules and chromogen applied following rupture, or alternatively, chromogen
can be
positioned in the capsules.
Examples of eligible acidic developer material include: clays, treated clays
(ILS. Patent
Nos. 3,622,364 and 3,753,761); aromatic carboxylic acids such as salicylic
acid; derivatives
of aromatic carboxylic acids and metal salts thereof (U.S. Patent No,
4,022,936); phenolic
developers (U.S. Patent Nos. 3,244,550 and 4,573,063); acidic polymeric
material such as
phenol-formaldehyde polymers, etc. (U.S. Patent Nos. 3,455,721 and 3,672,935);
and metal-
madified phenolic resins (U.S. Patent Nos. 3,732,120; 3,737,410; 4,165,102;
4,165,103;
4,166,644 and 4,188,456).
Processes of microencapsulation are now well known in the art. U.S. Patent No.
2,730,456 describes a method for capsule formation. Other useful methods for
microcapsule
manufacture are U.S. Patent Nos. 4,001,140; 4,081,376 and 4,089,802 describing
a reaction
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between urea and formaldehyde; U.S. Patent No. 4,100,103
describing reaction between melamine and formaldehyde; British
Patent No. 2,062,750 describing a process for producing
microcapsules having walls produced by polymerization of
melamine and formaldehyde in the presence of a styrenesulfonic
acid. The more preferred processes, in this invention, for
forming microcapsules are from urea-formaldehyde resin and/or
melamine formaldehyde resins as disclosed in U.S. Patent Nos.
4,001,140; 4,089,802; 4,100,103; 4,105,823; or 4,552,811. The
process of 4,552,811 is preferred.
The record material includes a substrate or support
material which is generally in sheet form. For purposes of
this invention, sheets can be referred to as support members
and are understood to also mean webs, rolls, ribbons, tapes,
belts, films, cards and the like. Sheets denote articles
having two large surface dimensions and a comparatively small
thickness dimension. The substrate or support material can be
opaque, transparent or translucent and could, itself, be
colored or not. The material can be fibrous including, for
example, paper and filamentous synthetic materials. It can be
a film including, for example, cellophane and synthetic
polymeric sheets cast, extruded or otherwise formed.
Binder material can be included to assist adherence
of the capsules to the substrate and can include materials such
as polyvinyl alcohol, hydroxy ethylcellulose, methylcellulose,
methyl-hydroxypropylcellulose, starch, modified starches,
gelatin and the like. Latex such as polyacrylate, styrene-
butadiene, rubber latex, polyvinylacetate and polystyrene can
also be advantageously used.
The examples which follow are given to illustrate the
14
CA 02092232 2000-OS-04
69601-96
invention and should not be considered as limiting. In the
examples all parts or proportions are by weight and all
measurements are in the metric system, unless otherwise stated.
14a
The principles, preferred embodiments, and modes of operation of the present
invention have been described in the foregoing specification. The invention
which is intended
to be protected herein, however, is not to be constmed as limited to the
particular forms
disclosed, since these are to be regarded as illustrative rather that
restrictive. Variations and
changes can be made by those skilled in the art without departing from the
spirit and scope
of the invention.
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EXAMPLE 1
Ascertaining Media Surface Temperature Using; Fax Machine
Coatings of color former dispersion were prepared on a thin translucent paper
substrate. Segments of the coatings were taped to a sheet of bond paper and
used as the copy
sheet in a Canon Fax-230. Melting was readily evident as clear (amorphous)
characters on a
relatively opaque background. Using this technique, the temperature at the
surface of the
media or sample was determined to be at least above 170°C with a
Canon*Fax-230.
Color Former Melting Temp. + Melt in Fax?
diButyl N102 ~ 170C Yes
PSD-150 ~ 200C No
Green 118 ~ 230C No
+ As determined using the grinds on Kofler Hot Bar
*Trade-mark
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EXAMPLE 2
Microcapsule Preparation
Internal Phase (IP)
20 g N102
180 g Trimethylolpropane triacrylate (TMPTA) monomer
2 g 2-Isopropyl Thioxanthone Photo Initiator
2 g Ethyl-4-Dimethylamino benzoate Photo Initiator
24 g 2,2-Dimethoxy-2-phenyl Photo Initiator
acetophenone
Combine the first two components and dissolve with heat, then dissolve the
photo
initiators.
External Phase !EP)
25 g Colloid 351 (-25% solids) Acrylic polymer, Rhone-Poulenc (butyl
acrylate)
198 g Water
Adjust pH to 5.0 using 20% NaOH.
Emulsification
Place 170 g of EP in blender and with mild agitation add the IP solution.
Increase the
blender speed to achieve desired drop size (eg., 50% of volume approximately
4.0~)
measured by Microtrac particle size analyzer from Leeds and Northrup
Instruments,
North Wales, PA 19454.
*Trade-mark
-17-
69601-96 ca 02092232 2ooo-os-o4
Encapsulation
Combine the following:
25 g Colloid 351 (-25% Solids)
42 g Water
pH adjusted to 4.8 with 20% NaOH
30 g Cymef 385 (--80% solids)
Add 70 g of the above to the emulsion and transfer to a vessel in a water
bath. With
stirring, heat the emulsion to 65°C and allow to process several hours
for
encapsulation to occur.
*Cymel is a trade mark of American Cyanamid Company. Cymel 385 is an
etherified
methylol melamine oligomer.
Coating
Combine equal weight parts of:
1. Finished capsule dispersion
2. 10% aqueous solution of AirvoI 103
This mixture is applied to paper or other desired substrate using, for
example, a fixed
gap applicator set a 0.001 inch. The resultant dried coating can be used to
make a latent copy
in a thermal printer such as a commercial facsimile machine.
The latent image copy can be developed by contacting with or applying on an
appropriate developer for the N102 color former. A typical example would be a
20% solution
of Durez27691 (p-phenylphenol formaldehyde resin) in xylene. The resin can
also be applied
in aqueous dispersion or emulsion form and then heated to promote the
development of the
black copy.
**Trade-mark
-18-
69601-96
CA 02092232 2000-OS-04
If desired, the resultant copy may be "fixed" or deactivated to thermal and/or
pressure
response by exposing to U.V. to polymerize the components. Approximately S
second
exposure to 15 Watt GE~'~ulbs (F15T8-BLB) is sufficient to "fix" the copy.
After fixing, the
sheet is resistant to scuff or abrasive induced markings.
Because of the reactive nature of the coating prior to fixing, the coating can
suffer
handling damage. This damage can be reduced by applying an overcoat that does
not interfere
with the thermal imaging nor with the subsequent fixing exposure. A typical
overcoat would
be the application of a 10% aqueous solution of Airvol' 540 using a #3 wire
wound rod.
*Airvol is a trade mark of Air Products and Chemicals, Inc. and is a polyvinyl
alcohol.
The photoinitiators can be omitted in the capsules of the latent image
receiving sheet.
Chromogen can be optionally included or excluded as desired.
**Trade-mark
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69601-96
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EXAMPLE 3
DRY DEVELOPMENT
a. Two sheets were prepared:
- microcapsule formulation of Example 2 was coated on one sheet
- color developer formulation was coated on another.
b. The capsule containing sheet was imaged with a thermal print head.
c. The imaged capsule sheet was coupled face-to-face with a color developer
sheet.
The developer sheet is a sheet coated with a phenolic resin dispersion Durez
32421 phenolic resin dispersion (~ 50% solids) benzoic acid, 2-hydroxy
polymer,
with formaldehyde, nonylphenol and zinc oxide. Both sheets coupled together
were sent between two fusing rolls heated to 110°C.
d. The substrate of the color developer sheet was peeled off.
It revealed a fully developed image remaining on the imaging sheet.
*Trade-mark
-20-
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EXAMPLE 4
INTERNAL PHASE (IP)
160 g TMPTA
40 g Durez 27691 (p-phenylphenol formaldehyde resin)
S 12 g 2,2-dimethoxy-2-phenylacetophenone (photoinitiator)
With heating, dissolve the resin in the TMPTA, then add the photoinitiator and
dissolve. This IP was encapsulated as in Example 2 and resultant capsule
dispersion coated
and top coated. The coated media was run through a commercial facsimile to
produce an
image. This image was developed by application of a commercial toner such as
Minolta MT
Toner II. The black toner particles selectively adhere to the image-wise
broken capsules.
Toner in the background was removed by gentle brushing, etc. The toner is
fused by heating
in an oven or on a heated drum or the like.
EXAMPLE 5
Same as Example 4, but imaging with FAX and toner application steps were
repeated
to add second color. Multicolor images can be obtained using repetition of the
process.
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EXAMPLE 6
PLAIN PAPER~I'RANSFER IMAGE
a. Plastic sheet imaged with toner (as in Example 3 or 4) was coupled with
bond
paper, and both sheets were sent together between two fusing rolls heated to
90°C.
b. Plastic sheet was removed.
c. Transfer image was obtained on plain paper.
EXAMPLE 7
IMAGING WITH TONERS
a. Melamine formaldehyde (MF) microcapsules containing sec-butyl biphenyl
solvent (SureSol 290) only were prepared according to the invention.
b. Imaging sheet was made by coating microcapsules on a plastic sheet and
applying
PVA overcoat.
c. Latent image was produced using Canon*230 FAX machine in a copy mode.
d. Portion of the sample was placed into a container with a commercial toner
(electrostatic copier toner).
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e. The container was tightly closed and shaked to deposit toner on the sample
surface.
f. After excess toner was removed from sample using brush, red image on white
background was obtained.
EXAMPLE 8
IMAGING WITH THERMAL TRANSFER RIBBON
a. Microcapsule latent imaging sheet, which did not contain dye, or color
developer
was used.
b. A latent image was recorded onto the sheet using a Canon 230 facsimile
machine.
c. The imaged sheet with selectively broken capsules or latent image was
brought
into the contact with the coated side of a thermal transfer ribbon and sent
through
heated fusing rolls.
d. When plastic of thermal transfer ribbon was removed, a colored image on the
microcapsule imaging sheet was obtained.
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EXAMPLE 9
TRANSFER SHEETS
a. A latent image was recorded onto a sheet containing empty or solvent - only
microcapsules using a Canori 230 facsimile machine.
b. Blue color ink was evenly distributed on the surface of the above sheet.
c. The excess ink was removed by pressing inked imaging sheet against smooth
clay
coated paper.
d. Inked surface of above sheet was positioned on top of plain paper sheet and
sent
through a steel pressure rolls nip. (Applied pressure = 170 pli). Blue high
contrast
print was obtained on paper. pli = pounds per lineal inch.
e. In a variation, black commercial printing press ink was used. Excess ink
was
removed from the sample using blade-like tool. After the transfer to paper,
black
print on clean white background was obtained.
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EXAMPLE 10
TRANSFER SHEET
Internal Phase (IP)
180 g trimethylolpropanetriacrylate (TMPTA) monomer
20 g 1,3,3-trimethylindolino-6'chloro-8'methoxybenzopyrylospiran
12 g 2,2-dimethoxy-2-phenylacetophenone (photoinitiator)
Combine components and dissolve with heat. This IP was encapsulated as in
Example
1 and resultant capsule dispersion applied to suitable substrate using a #12
wire wound rod.
The coating was dried and top coated with a 10% aqueous solution of Airvol 540
using a #3
wire wound rod. The coated media was run through a commercial facsimile to
produce a
master image. When the master image was heated in contact with a developer
sheet, a copy
was obtained due to sublimation of the spiran from the image-wise broken
capsules. The
imaged master could be used multiple times to make additional copies. Imaged
copies are
obtained on a commercially available carbonless CF sheet such as comprised of
a p-
phenylphenol formaldehyde type resin.
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