CA1058393A - Multi-detectable ink compositions and methods of use - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A machine readable marking ink composition having two or more mixed pigments for processing and distinguishing articles both visually and under radiation of a discrete predetermined wavelength. The composition includes from 0.5 to 10% non-fluorescent pigment and from 2.0 to 25.0% fluorescent pigment which fluoresces under radiation at a predetermined wavelength.

Description

Background of the Invention In the machine processing o~ various types of informa-tion contained on tickets, tags, labels, postage impxints and the like it is generally known to employ detectors which are responsive to shape relationships and/or colors, and in many cases to the fluorescence of an ink which may be excited, for example, by ultraviolet light. Fluorescent inks and dyes have long been known as, for example, those disclosed in U. S.
Patents Nos. 2,681,317; 2,763,785; 3,230,221; 3,412,104;
3,452,075; and 3,560,238. The fluorescent inks and the methods of making or using them as known in the prior art, generally entail the use of a fluorescent ink which, when irradiated, will fluoresce and emit radiatton within the wavelength for I the particular fluorescent color of that dye or ink. It is I known, for example, in the postage meter art to provide a red fluorescent ink for machine reading of processed mail.
The fluorescent detectors, however, are generally designed or set to pick up emissions only within a certain range of wavelengths and accordingly, the coloration of the ink will be dependent upon the formulation which provides for fluores-cence under light such as ultraviolet light, to emit radiation of a certain wavelength.
It is desirable, however, to provide tickets, tags, labels, postage meter imprints, stampings, or the like with a greater variety of visual color for classification, for inventory ` purposes or sorting, for example, so that the tags, tickets, envelopes and the l~ke are, or may be, processed visually by people, as well as by one or more machines. A problem arises, 29 however, when a variety of ~isual colors are used since the cb/ ~ a - .. - . , , . . ................... , i . ~ .

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-`` 1058393 visual color is generally related to the fluorescent color of the ink when it is irradiated. Thus, ifthere ls a mixture of different tags, tickets, or letters which are to be machine read, the machine must be responsive to a broad spectrum of - emission wavelengths or the machine must be adjusted to receive the wavelengths of the various fluorescent ink colors as they are processed.
Accordingly, it is an object of the invention to ' provide means for having two different colors contained in the i 10 same ink, one an ordinary mixed light color and the other a fluore~cent color.
Other objects of the invention will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises a method and a composition of matter possessing the characteristics, properties, and the relation of components wh~ch will be exemplified in the composition and the method of use thereof hereinafter des-cribed, and the scope of the invention will be indicated in ; the claims.
Summar~ of the Invention The invention relates to novel ink compositions and methods o~ using such ink compositions, and more particularly to such compositions and methods wherein the fluorescent emission of ink under irradiation is maintained within relatively narrow limits of wavelength while the v;sual colors of the inksmay vary widely for visual sorting and the like. The ink ~ormulations generally comprise from 2 to 25 percent fluorescent pigments with 0.3 to 10 percent non-fluorescent pigments in a vehicle 29 which contains surfactants and gels and/or antioxidants. The . .
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' '. ' ~ ` ~ ';' ink compositions are made ~rom a combination of pigments includ-ing daylight fluorescent pigments which are solid i~lutions of fluorescent dyes in friable organic resins. Thus the pigment combinations provide a variety of colors to the eye or to an optical reader, but all provide for fluorescent emission within a relatively narrow wavelength to make it possible to machine read tickets, labels, mail or the like with a single setting of a fluorescent detector device while providing for a variety of visually differing colors in accordance with the method of the invention. The visual differing colors can be also optic-ally read by a machine to provide a second mark or set of data - -from that read by the fluorescent detector. The visual color of the ink is a color other than red while the fluorescent color of the ink is preferably red or orange-red.
- In one particular aspect the present invention provides a machine-readable marking ink composition having two or more mixed pigments for processing and distinguishing articles both ; visually and under radiation of a discrete predetermined wave-' length, comprising (Al from 0.5 to 10 percent non-fluorescent pigment by weight, (~ from 2.0 to 25.0 percent fluorescent pigment by weight which fluoresces under radiation at a pre-determined wavelength, 1. said fluorescent pigment being taken from the group consisting of (al fluorescent pigment dispersions in a vehicle which comprises a resin dissolved in a narrow fraction petroleum distillate having a boiling range of from about 440~F to 510~F, (b) fluorescent pigment dispersions in ; a dxying type alkyd resin, or ~c~ comminuted solid solutionsof fluorescent dyes in modified sulfonamide resins, (Cl 29 from 0.25 to 1.5 percent surfactant by weight, (D) from 0.25 , .
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to 5 percent gellant by weight, and (E) all of said pigments, said surfactant and said gellant being in a vehicle for the mixed pigment system, 1. said vehicle consisting essentially of a mixture of (a) dioctyl phthalate and (b) an aliphatic hydrocarbon having a distillation range of about 310C to 345C, ; whereby the color of the ink under mixed light is different than the fluorescent color of the ink when irradiated at the fluorescent wavelength of said fluorescent pigment.
DESCRIPTION OF PREFERRED EMBODIM~NTS OF THE INVENTION
In accordance with the method and ink composition of the invention, machine-readable ~ickets, tags, labels, postage imprints and the like are provided with a visual color, i.e.
a color under ordinary mixed light frequencies and a fluorescent radiation color which when irradiated with ultraviolet light, . for example, fluoresces preferably in thé red wavelength of ; about from 5800~ to 6200A. Since there are existing machines for reading fluorescent ink 1mprinted information, a variety of visual colors can be employed with the fluorescent color of the ink being within the red portion of the spectrum.
Thus the ink imprint may be read v;sually or by some other type ! of optical machine reader and then read by a fluorescent machine reader which is set to pick up the fluorescent wavelength of the ink. This is particularly useful in the field of postage imprinting since at large postal installations machines may be available to read postage information, but at many smaller or rural stations the postage imprint must be visually read.
Further, by the use of a visual or optical color which is differ-ent from the fluorescent color a combination of information may t 29 be imprinted which is readable by two different machines, i.e.

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an optical reader which is responsive to the reflected color and/or shape of the imprint under ordinary mixed light and a fluorescent reader which responds to the particular fluorescent wavelength when the lnk is irradiated.
The inks may have ordinary mixed light colors of orange, brown, purple, black, blue or green, for example, while emitting orange-red fluorescence when activated by long or short ultra-violet waves. The general formulation is a combination of fluor-escent and optical pigments with the fluorescent pigments com-prising about 2 to 25~ and preferably about 10 to 20% by weight with the non-fluorescent pigments making up from about 0.3 to 10% and preferably from 0.5 to 2.5% by weight of the ink formulation. , The pigments are carried in a vehicle which comprises about 75 to 95~ of the ink by weight and preferably comprises a mixture of dioctyl phthalate and an aliphatic hydrocarbon having a distillation range of about 310 to 345C., which is sold by East Coast Chemicals Co. as "Esco~lex R 175." The ratio of dioctyl phthalate to the aliphatic hydrocarbon is about 3:1 by weight. To the vehicle there is added about .25 to 1.5% sur-factant and about .25 to 5~ gellant all by weight. The preferred surfactant is lecithin and the preferred gellant is aluminum -stearate having a high free stearic acid content made up as a 10% gel in a vehicle which is the same or is compatible with the ink vehicle. There may also be added up to about 1% anti-oxidant and the preferred antioxidant is eugenol.
The fluorescent pigments are dispersions in a heat~
set type ~ehicle which comprises, for example, a suttable ; resin dissolved in a high boiling narrow ~raction hydrocarbon 29 solvent or are dispersions o~ the fluorescent pigments in a cb/

-`: 1058393 drying type alkyd resin such as Trionol ~ No. 3 sold by Lawter Chemicals, Inc. The fluorescent pigments are solid solutions of fluorescent dyes in friable organic resins A typical example would be a powdered thermo-plastic melamine-sulfonamide-formaldehyde resin which contains various dissolved fluorescent dyes wherein the resin is the matrix for the dye. The daylight fluorescent pigments preferred are thus modified sulfonamide resins containing fluorescent dye or dyes in solid solution.
The other pigments used as set forth in the Examples below are used to impart the desired visual color which is substantially different from the fluorescent color under ultraviolet light.
The visual pigments are generally in a heat-set type vehicle, a litho varnish or a mixture of dioctyl phthalate and an aliphatic hydrocarbon having a distillation range of about 310C to 345C
in a ratio of about 3:1. This is set forth as PRV (porous roller vehicle) in the Examples below.
The following Examples are exemplary of the invention and should not be considered limiting.

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~", EX~PLE I (ORANGE¦

% By Weight -. % By Weight Commercial in Ink (incl.
in Ink Designation vehicle) Source -Strong Red Orange 7.70 D516 Dispersion 15.40 Lawter Chemicals, Benzidine Yellow 1.50 FS1117 Thermex~ Inc.
Flush 6.00 Chemetron Corp.
Brilliant Toning Red 0.80 FL-10-707 PRV1.77 Sherwin Flush Williams . Chemicals .~ 10 Aluminum ~tearate 0.50 10% Gel in PRV 5.00 Witco ; Chemical i Corp.

P~olyvinyl Chloride 0.12 MarvinolOE3 50 3% Gel in PRV 4.00 Uniroyal, ~c Inc.
, Lecithin 0.50 Lecithin U.F. 0.50 A.E. Staley , Mfg. Co.

Eugenol 0.50 Eugenol U.S.P. 0.50 Fritzsche Dodge &

~ Inc.
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.~ 20 Vehicles 88.38 DOP PX-138 50.13 U.S. Steel Corp.
,~! Chemical i~,' Div, Escoflex~ 175 16.71 East Coast i - Chemicals ~, Co.
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The procedure used for a 100 pound batch of ink in accordance with this Example is as follows. First the Dioctyl ~1 Phthalate, Escoflex ~ 175, Eugenol and l,ecithin are weighed into a ten gallon tank and mixed to form the vehicle solution. The gel(s) . and pigments are then weighed into a twenty gallon mixing vessel and blended with a mixer until the mixture is uniform which should take about 15 to 20 minutes. If there are any undispersed gels -b/ - 7 -' ,., or pigments the stirring should continue until the mixture is uniform. The gel pigment dispersion is continued to be stirred - and 1-1/2 to 2 gallons of the vehicle solution is added to the dispersion and is stirred for a period of about 5 to 10 minutes before the addition of the remaining vehicle solution. The ink is then stirred for about 30 minutes more and is then strained through four to six layers of cheesecloth before it is run on a high-speed mixer for about 15 minutes. The ink is then allowed to stand for 10 hours or more (such as oyernight) 10 and is then stirred for about 15 minutes with a propeller mixer and again for 15 additional minutes with a high-speed mixer, again allowed to stand for over 10 hours and is then stirred once more with a propeller mixer, after which it is ready for use.

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~,~ EX~MPLE II (BROWN) ,~ The procedure for preparing the in~ in this Example is the same as that set forth in Example I, above, except that , the formulation is as follows:
By ~eight By Commercial in Ink lincl.
- Weight Designation vehicle) Source ~-- lligh Intensity 13.981~6118 27 . 96 Lawter Chem.
~,~' Yellow Orange Dispersion ?~';
,~, 10 Carbon Black 0.87 W-92 Flush 3.06 Chemetron Corp.
.' Phtllalocyanine ~ ~
, Green0.15 5-65-F-423 0.43 Hilton Davis ~, Flush Div. Sterling Drug, Inc.
Aluminum Stear-~'~, ate O. 50 1096 Gel in PRV 5.00 Lecithin0.50 Lecithin U.F. 0.50 ~, Eugenol0.25 Eugenol U.S.P. - 0.25 Vehicles83. 75 DOP PX-138 47.10 Escoflex 175 15.70 s;
~, EX~MPLE III (PURPLE) The procedure for preparing the ink in this Example is the same as that set forth in E~ample I, above, except that the ~' formulation is as follows:
'~ Pink 18.52 11622 Dispersion37.04 Lawter Chemicals Alkali Blue G.G. 0.37 FL-15-403 Flush 1.09 Sherwin-Williams Aluminum Stearate 0.50 10% Gel in PRV 5.00 Lecithin 0.50 Lecithin U.F. 0.50 Eugenol 0.25 Eugenol U.S.PØ25 Vehicles 79.86 DOP PX-138 42.09 Escoflex(~) 175 14.03 : .

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EXAMPLE IV (BLACK) The procedure for preparing the ink in this Example is the same as that set forth in Example I, aboye, except that the formulation is as follows:
,, % Bv Welght ' ~ By Commercial in Ink (incl.
Weight Designation vehicle~ Source Strong Yellow Orange17.09 H618 Disper-34.18 sion Alkali Blue G.G. 0.73 FL-15-403 2.15 ''."! Aluminum Stearate0.50 10% Gel in PRV 5.00 ....
; Lecithin 0.50 Lecithin U.FØ50 Eugenol 0.25 Eugenol U.S.P. 0.25 Vehicles 80.93 DOP PX~13843.44 . Escoflex ~ 175 14.48 -EXAMPLE V ~BLUE) The procedure for preparing the ink in this Example is the same as that set forth in Example I, above, except that the !'., 20 formulation is as follows:
~i~ Strong Red9.00 EI636 Dispersion -18.00 Lawter , Chemicals ~' Phthalocyanine '~ Blue 1. on FS1116 Flush3.57 Chemetron ~$,~ Aluminum Stear-ate0.50 10% Gel in PRV 5.00 ,.. .
i;~` Lecith~n 0.50 Lecithin U.SØ50 Eugenol 0.25 Eugenol U.S.PØ25 ~",~
Vehicles 88.75DOP PX-138 54.51 ~! 30 EScoflex ~ 1~5 18.17 C?/ - 10 -. 'i ' ~ ~, .. . .

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~. . , ;; , ; EXAMPLE VI (GREEN) , .
'- The procedure for preparing the ink in this Example is the sa~e as that set forth in Example I, above, except that :~ the formulation is as follows:
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~ By Weight o % By Commercial in Ink (incl.
,~, Weight Desiqnation vehicle) Source ' Strong Yellow Orange10.55 ~618 Dispersion 21,10 Phthalocyanine Green1.58 5-65-F-423 Flush 4.51 ~" Strong Lemon ~' Yellow3.16 D541 Dispersion 6.32 Lawter Chem-~;, icals ~, Aluminum Stearate0.50 10% Gel in PRV 5.00 ~ Lecithin0.50 Lecithin U.F. 0.50 5,~ ~ugenol0.25 Eugenol U.S.P. 0.25 ~, Vehicles83.46 DOP PX-138 46.74 Escoflex ~ 175 15.58 In the above Examples the same constituents contain a fraction of solids by weight which account for the difference5 in the percentages of the constituent alone versus the constituent-plus vehicle which is admixed to make the ink composition.
In the above Examples the aluminum stearate has a high free steric acid content and the polyvinyl chloride used had an inherent viscosity of 1.20 and a specific viscosity of 0.50.
The carbon black in the above Examples may be any suitable pig-ment black, and for the above Examples the carbon black was dis-~" persed in a gloss-type vehicle. The non-fluorescent pigments are known such as benzidine yellow which is a common yellow pig-~i ment which is flushed in a heat-set type vehicle. The brilliant ~' :
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toning red pigment is also identified as permanent Red 2B (Color Index 15865 - Pigment Red 48) which is flushed in porous-roller vehicle. The phthalocyanine Green is Pigment'Green 7 (Color Index 74260) whlch is flushed in a litho varnish. It is designa-ted by the supplier (}lilton Davis) as Synthaline~ Green. The Alkali Blue GG is a well known Pigment Blue 19 (Color Index 42750A) which is also flushed in a litho varnish. The Phthalo-i;;~ cyanine Blue is Pigment Blue 15 (Color Index 74160~ which is flushed in a heat-set type vehicle.
The ink can be applied in a number of ways by stamps, ;~ from rollers or by an appropriate printing device. While fluores-~`~ cent wavelengths of other than red or red-orange may be employed, a red or red-orange is preferred since there are existing detectors ~; which are specifically designed for this wavelength of fluorescent . ..................................................................... .
,~ ~ radiation. In any event the fluorescent emission should be with-,, in certain limits of wavelength so that there is no need to '~ continually adjust or reset the fluorescent detector each time a new color is being processed. Thus in accordance with the r,.': invention a number of visual colors may be imprinted, but will ,~, 20 all be machine readable by at least the same fluorescent detector.
~;~' In practice, for example, when used for postate imprint-ing the ink may be carried on or in rollers, belts, pads, or , ..................................................................... . . .
;~ the like for transferring the proper print configuration to a .... .
;i~ letter or postage imprint tape. Once imprinted the mail-carrying -~

,~ imprint with such ink can be checked visually by the human eye , or, depending upon the postage imprint configuration, by an '- optical detector which may be activated by the reflection of `,' ordinary mixed light from the postage imprint~ The same or ~ 29 othex portions of the postage imprint may be further read by a ,. . .
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10583g3 fluorescent detector when the postage imprint is subjected to, for example, ultraviolet radiation, Additional information contained in the postage imprint can be picke~ up by the fluores-cent detector. Mail sorting and routing, as well as the machine -verification of postage amounts and other such functions can be facilitated by the dual emissive ink in accordance with the invention. Sim1larly, the method of the invention may be employ-ed in the marking of retail price tickets and the like to provide dual emissive characteristics for machine sortlng and/or compila-tion of sales or inventory information.
The ink may also be used to verify the source of pro-ducts. Phonograph records, for example, may be marked with the dual emissive ink and by detection of the fluorescent color by the human eye or by machine, counterfeit records may be separated from the genuine ones. The ink may also be used in decorative displays wherein by changes from mixed light to fluorescent the design made with such an ink would change.
It will thus be seen that the ob]ects set forth above, among those made apparent from the preceding description, are efficiently attained and since certain changes may be made in the above methods or in the compositions and formulations without departing from the scope of the invention, it is intend-ed that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

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Claims (4)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A machine-readable marking ink composition having two or more mixed pigments for processing and distinguishing articles both visually and under radiation of a discrete predetermined wave-length, comprising A. from 0.5 to 10 percent non-fluorescent pigment by weight;
B. from 2.0 to 25.0 percent fluorescent pigment by weight which fluoresces under radiation at a predetermined wavelength 1. said fluorescent pigment being taken from the group consisting of (a) fluorescent pigment dispersions in a vehicle which comprises a resin dissolved in a narrow fraction petroleum distillate having a boiling range of from about 440°F to 510°F, (b) fluorescent pigment dispersions in a drying type alkyd resin, or (c) comminuted solid solutions of fluorescent dyes in modified sulfonamide resins;
C. from 0.25 to 1.5 percent surfactant by weight;
D. from 0.25 to 5 percent gellant by weight; and E. all of said pigments, said surfactant and said gellant being in a vehicle for the mixed pigment system,

1. said vehicle consisting essentially of a mixture of (a) dioctyl phthalate and (b) an aliphatic hydrocarbon having a distillation range of about 310°C to 345°C, whereby the color of the ink under mixed light is different than the fluorescent color of the ink when irradiated at the fluorescent wavelength of said fluorescent pigment.

2. The machine-readable marking ink of Claim 1 wherein the fluorescent wavelength of said fluorescent pigment is from 5800 A to 6200 A.

3. The machine-readable marking in of Claim 1 wherein said surfactant is lecithin and said gellant is aluminum stearate.

4. The machine-readable marking ink composition defined in Claim 1 wherein said vehicle consists substantially of a mixture of said dioctyl phthalate and said aliphatic hydrocarbon in a ratio of about 3:1.