CA2278145C - Heat resistant security document - Google Patents
Heat resistant security document Download PDFInfo
- Publication number
- CA2278145C CA2278145C CA002278145A CA2278145A CA2278145C CA 2278145 C CA2278145 C CA 2278145C CA 002278145 A CA002278145 A CA 002278145A CA 2278145 A CA2278145 A CA 2278145A CA 2278145 C CA2278145 C CA 2278145C
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- composition
- security document
- color
- document
- printed
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
- B41M3/00—Printing processes to produce particular kinds of printed work, e.g. patterns
- B41M3/14—Security printing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
- B41M3/00—Printing processes to produce particular kinds of printed work, e.g. patterns
- B41M3/14—Security printing
- B41M3/142—Security printing using chemical colour-formers or chemical reactions, e.g. leuco-dye/acid, photochromes
Abstract
A security document is provided containing a color-forming composition having an insulating material therein which allows the document to be passed through heated printing devices such as laser printers without the problem of premature color development. The color-forming composition includes a mixture of a color former, a color developer, and an insulating material. In a preferred embodiment, a toner adhesion-enhancing composition containing an insulating material is applied over the color-forming composition. The security document may be used to provide an authentication feature and/or an indication of attempted alterations from the use of solvents, heat or abrasion.
Description
HEAT RESISTANT SECURITY T~UCUMENT
The present invention relates to a heat resistant security document containing at least one composition which activates to produce a color upon the application of a solvent, heat or abrasion. More particularly, the invention relates to a. security document having an insulating material blended with. such an activatable composition which allows the document to be passed through heated non-impact printing devices such as laser printers without the problem of premature color development. The c:omposi..tion~;s) may be used to provide authentication and/or security features on ;~.
document.
Security documents are printed on a wide variety caf commercial printing devices. Traditional mechanical impact printers have been typically been used ire. the past for printing information ors security documents such as checks.
The inks used with most impact printers adhere well to a document due to the par. tial penetrs.tior~ of the ink i.nt~.~ the surface of the document substrate. In addition, dyes or other coatings may be applied to the documents to aid ixi the prevention of fraudulent alteration of security documents.
For example, U.S. Patent No. 5,209,51.5 teaches a solvent and/or pressure sensitive coating Comprising a mixture of a color former and a color developer may be used to produce covert images on a security doc~zment. Lf attempted alteration of such a document is made by the application of solvents and/or pressure, the color former and/or color developer dissolve and react t:o form a visible image on the substrate, providing easy detection of the attempted alteration.
However, with the advance of microcomputer technology, a number of faster printing methods have been developed to take advantage of the high-speed printing output: which is mcaw possible. Laser printers are an example of nonimpact printers which are faster, quieter, and more reliable than impart -printers. Such printers operate by fusing toner images onto a substrate by passing the substrate through s. pair of rolls which apply both heat and pressure.
However, such printers have significant limitations which have prevented their wide use in printing documents such as checks and other security documents. Une limitation is the inability to achieve satisfactory toner bonding on a large variety of paper products used to make such documents. Because of the lack of strong adherence of toner to paper, documents printed using such printers may be subject to deliberate alteration by counterfeiters, forgers, and the like.
Toner adhesion-enhancing coat~..ngs have been developed which improve the adhesion of. toner to the documents. For example, U.S. Patent No. 5,0~5,42~ to Maierson et al describes a polymeric toner adhesion-enha~xcing composition for use on documents printed with noncarztact ~>rinting devices. However, documents containing such toner adhesionMenhancing coatings may still be subject to alteration by other methods as the solvent sensitive coatings used in the art as described above cannot withstand passage through a laser printer. This is due to the high temperature of the toner fuser callers which will melt the dye and/or developer and cause premature color.
development on the documents.
accordingly, there is stir. a need in the art for a security document which may be printed using a high-speed printing device such as a laser printer without the problem of premature coloration and which has security features which can provide authentication of the document and/or indicate attempted alterations of the document.
The present invention meets that need by providing an insulating material for use on security dacuznents wr~ich, in combination with a color-forming composition and/or a toner adhesion-enhancing composition, provides heat resistance to prevent premature coloration when the documents axe passed through a printing device such as a laser printer. The:
security document may be used to provide an authentication feature and/or an indication of attempted alterations from the use of solvents, heat, or abrasion.
According to one aspect of the present invention, a security document is provided which is resistant to premature coloration by heat. The document comprises a substrate having first and second major surfaces with at least a portion of one of the major surfaces having thereon a composition which activates to produce a color upon the application of a solvent, heat sufficient to cause the composition to melt:, or abrasion. The color-forming composition also includes an insulating material to provide heat resistance when the document is passed through a noncontact printing devicE= such as a laser printer.
By resistant to premature coloration by heat, it is meant that the composition ors the document will. not activate to form a color when exposed to temperatures of about 450 to 475°F
1232.22 to 246.11°C) for a period of about 0.5 seconds or less, which typically occurs when a document is passed through a noncontact printing device such as a laser printer.
Accordingly, while the document will not activate prematurely when exposed to such a source of heat, it rnay still be activated when exposed to heat for a time and temperature which is sufficient to cause the reactants in the color_-forming composition to melt, i.e., at a temperature of about 400°F {204.44°C) for at least about ~. second.
The color-forming composition preferably comprises a mixture of initially colorless color formers and color developers, and in a. preferred embodiment, includes a binder.
Preferably, the color former comprises a leuco dye having a melting point of greater than about 150°C. The color developer preferably camprises a phenolic resin having a melting point of greater than about 150°C. "fhe composition is preferably applied to the substrate to provide a dry coating weight of between about 0.4 and 0.5 lbs./1300 f12 CA 02278145 2003-06-02 "
(1.52 to 1.9 g/m2) (17 x 22", 500 sheet ream). The composition may be printed on one or more areas of the substrate and on one or both sides of the substrate. The composition may be printed in the form of covert warning indicia such as the ward "VOID" or any other symbol which would alert;: a user to an attempted alteration.
Alternatively, or in addition, the composition may be printed on the substrate in the form of covert authentication indicia such as the words "VALID" or "AUTHENTIC" or any other symbol which would indicate to a user the genuineness of the document. In one embodiment, the warning irxdicia are printed on one surface of the substrate, while the authentication indicia are printed on the opposite surface. In another embodiment, the warning and authentication indicia are interspersed. on the swine surface of the document .
The insulating material included in the color-forming composition functions to prevent heat transfer from the fuser rolls of a laser printer to the composition, thus preventing melting of the color fc~rrner or color developer. which would ZO cause premature coloration on the substrate. The insulating material may be inorganic ox organa.c and may comprise ho7.low or solid polymeric particles. 'I'he partx.cles may be .in the form of hollow tubes or spheres. A preferred insulating material comprises hollow polymeric spheres of polystyrene.
The insulating material preferably comprises from about 10 to 20% by weight of the cc~lar-forming composition.
In a preferred embodiment of the invention, the security document further includes a toner adhesion-enhancing composition which overlies the color-forming composition, where the toner adhesion enhancing composition comprises a polymeric toner adhesion-enhancing coating and an insulating material. The toner adhesion-enhancing coating provides improved adhesion of toner particles to the security document when printed with a laser or other noncontact printer, while the insulating material. functions to prevent heat transfer to the color-forming composition underneath. Preferably, the polymeric toner adhesion-enhancing coating comprises a.
synthetic or natural latex, such as a carboxylated styrene-butadiene latex or styrene-butadiene latex.
The insulating material preferably comprises from about 20 to 40% by weight of the toner adhesion-ezxhancing composition, and preferably comprises hollow polymeric spheres comprised of polystyrene. The toner adhesion-enhancing composition is preferably applied to the substrate to provide a dry coating weight of 0.25 to 0.35 lbs./5300 ft.2 (0.95 to 1.33 g/mz) .
When the security document of the present invention is passed through a laser printer or other heated non-impact printing device, the color-farming composition is not activated due to the presence of the insulating material in the composition. Horaever, if the document is exposed to any number of common solvents, the solvent will penetrate the toner adhesion-enhancing layer on the substrate and the composition will activate such that the warning and/or authentication indicia will became visib~.e an the substrate.
The indicia will also become visible if the document is exposed to heat for a time which is sufficient to melt the color forming and color developing reactants in the composition, or if the document is subjected t:o abrasion., Accordingly, it is a feature of the present invention to provide a security document printed with a color-forming composition containing an insulating material which allows security documents to be printed using heated non-impact printing devices such as laser printers without premature color development on the document. zt is a further feature of the invention to provide a toner adhesioza-enhancing composition including an insulating material. therein which may be coated over the color-forming compasit,ion. These, .and other features and advantages of the present invention will ' CA 02278145 2003-06-02 -~..
become apparent from the following detailed description, the accompanying drawings, and the appended claims.
In order that the invention may be more readily understood, reference will now be made by example to the accompanying drawings, in which Fig. 1 is a fragmentary sectional view of a document substrate containing a color-forming composition and a. toner adhesion enhancing composition which include an insulating material; Fig. 2 is a front elevation view of a security document containing the color-forming composition initially printed as covert warning indicia; and Fig. 3 is a front elevation view of a security document including both authentication and warning indicia and illustrating the appearance of the warning indicia after alteration has been attempted.
The use of an insulating material in combination with a color-forming composition and/or a toner adhesion-enhancing coating provides the capability to use high speed noncontact printing devices su~.h as laser printers for printing a variety of security documents such as checks, negotiable certificates, transcripts, or other documents of value or documents which evidence value while still prozYiding a means of detecting fraudulent alteration of such documents.
The insulating material used in the present invention is in particulate form and preferably comprises small diameter polymeric particles, and most preferably comprises hollow polymeric spheres of polystyrene, The particles may take the form of hollow tubes ox spheres and may have a diameter of approximately 0.5 to 1 ~.m. ~1 preferred insulating material is Rhopaque HP 1055, available from Rohm and Haas. Other suitable insulating materials include solid spheres of polystyrene available from Dow Ohemical ~:ompany under the designation Dow 662x. Whether present in the color--forming composition, the toner-adhesion enhancing composition, or both, the insulating material functions too prevent, or at:
_7_, least retard, heat transfer to the color former and color developer in the color forming composition. Specifically, the insulating material prevents the leuco dye and color developer from reaching their melting points when exposed to the high temperatures generated from the heated fuser rollers of a laser printer, i.e. , from about. 4~Cf° to 4'~5°F
(232.22°C to 246.11°C).
The insulating material may be combined with the other components in the color-form~.ng~ composita.on and preferab7_y 14 comprises from about 10% to 20% by weigh. of the color-farming composition.
Suitable color forming dyes for use in the color-forming composition include any of the initially colon°less dye precursors conventianally used in this art and include, but 15, are not limited to, colorless leuco dye precursors such as crystal violet lactone, ben~oyl leuco methylene blue, :i.ndolyl red, malachite green lactone, 8'-methoxybenzoindoline spiropyran, and rhodamine lactone.
Suitable color developers for use in the color-forming 20 composition include, but are not limited to, phenolic :c-esins such as acetylated phenolic resins, sal~..c.ylic acid-modified phenolic resins, and novolac-type phenol.ic resins. ~1 preferred phenolic z°esin is 4,4-sulfony~.. diphenol. Both the color formers and color developers used should preferably have 25 a melting point of greater than 150°C to avoir~. premature coloration.
Preferably, the color-forming composition includes one or more binders which function to keep the composition in proper suspension for printinr~. Suitable binders include polyvinyl 30 alcohol or a grafted starch solution. Preferred for use is a grafted starch solution as it enhances the duality and color development of the words, indicia, or patterns activated on the document substrate.
As can be seen in the drawing figures, the color-forming 35 composition may be fully coated onto substantially the entire ...
surface of the substrate, spot-coated onto only one or more predetermined areas of the substrate, or printed as wards, symbols, or patterns. The color-farming composition may be printed as covert authenti.catian indicia, warning indi.cia, or a combination of both, For example, in embodiments where it is desirable to prevent fraudulent alteration of a document, covert indicia such as the words "VOID" or other images may be printed on the document. In embodiments where it i.s desirable t:o provide an authentication feature, words such as "VALID'", "AUTHENTIC", or other words, symbols, patterns, images or designs, such as company logos or geometric shapes nnay be printed on the document.
It should be appreciated that many different combinations for placement of the color-forming composition on a security document are possib:Le and are with:i.n the scope of this invention. For example, the composition may be printed as covert warning or authentication indicia on the ent.ire~
document, or only in certain areas such as ~~he area in. which a signature or monetary value is present. It may desirable far some embodiments to include authentication w.ndica on one portion of a document and covert warning .indicia on another portion of a document. For example, on a. security document such as a check, warning indicia may be printed in the areas containing monetary amounts while authentication indicia may be printed an other areas of the check whictl would not.
interfere with check processing. Alternatively, warning indici.a could be printed an one side of a d~>cvment and authentication indicia printed an the other side of the document.
In still other embodiments, it may be desirable to combine the authentication and warning indicia together as an interspersed pattern an a document such as VOID<>AUTHENTIC<>VOID<>AU'I'HENTIC etc. Whether the col.ar-forming composition is printed as warning indicia, . authentication indicia, or a combination thereof, the words or images should be printed so that they can easily be detected upon activation of the composition. Preferably, the color-forming composition is printed onto a security document by S flexographic printing. The composition is preferably applied to provide a dry coating weight. of between about 0.4 and 0.5 lbs/1300 ftz (1.52 to 1~.9 g/m2) .
The resulting security document will provide authentication or show attempted alteration by the use of most oxygenated solvents including alcohols, ketanes, esters and ethers. To increase the range of sensitivity of the color-forming compositions a hypochlorite sensitive compound such as amino benzyl thiozol (available from Bayer as Chlorostain OR*) may also be included. This compound provides protection against the use of hypochlorite agents wkxich could damage the color formers and/or valor developers and leave the document susceptible to alteration by solvents.
In embodiments where both warning indicia and authentication indicia are present on a document, the color forming composition used to print t:he warning indicia may comprise a different composition than the solar forming composition used to print the authentication indicia. For example, it may be desirable to have different compositions for the warning indicia and authentication indicia so that they may be activated by different solvents, i.e., the warning indicia could be printed with a color-forming composition which is activatable by a wide variety of solvents while the authentication indicia could be printed with a color-farming composition which is activatable by only one type of solvent.
The security document of the present invention will also provide authentication or show attempted al~:eration by the application of direct heat from a suitable heat source which causes the color forming and solar developing reactants in the color-forming composition to melt and act":ivate. The calar-forming composition will also activate by abrasion such as * Trademark -1f~-vigorous rubbing. While not wishing to be bound by any particular theory, it is believed that the insulating material migrates to the surface of the printed indicia, and. that vigorous rubbing removes the insulating surface layer on the document, allowing the color-forming reactants to come into intimate contact and/or become heated by friction such that they react.
In embodiments where a toner adhesion-enhancing composition is applied over the color-forming composition, the toner adhesion-enhancing composition is preferably applied to provide a dry coating weight of between. abaut 0.25 and 0.35 lbs. j1300 ft.z (.95 and 1.33 g/rn~) X17 x 22" ~ 500 sheet: ream) .
Suitable toner adhesion-enhancing compositions are taught in U.S. Patent No. 5,045,426 to Maiersan et al, U.S. Patent No.
5,017,416 to Imperial et al, arad published International apple.
No. WO 90/13064. A pre~~erred toner adhe~:~...on-enhanf~ing wompo-sition comprises a .natural or syrlt~net~c :iat:E~x such as ~_~arboxy-lated styrene-butadien~~~ latexes c~~- ~tya~tyrle-L:~ut:adiene l;~texes .
Carboxylated styrene-butadiene latexes suitable for use :in the present invention are available: from the Daw Chemical Company under the designations 615NA, 620NA, and 722NA.
The toner adhesion-enhancing composition preferably further includes from about 20~ to 40% by wez.ght of the insulating material, which provides further insulation to the color-forming composition underneath. ''fhe toner adhesion-enhancing coating is preferably applied to the substrate as an aqueous dispersion, and is preferably applied over substantially the entire surface of' the substrate to yield a dry coat weight of 0.3 to 0.4 1b/1300 ft.' (1.14 to 1..52 g/m2).
With reference to the drawings, it. must:;. be appreciated that Patent Of f ice .requirements f ax' sol ~.~3 black 1 ine drawings on a white surface make illustration of some of the subtleties of our invention re:Lating to different colors difficult by the required Patent Office drawings alone. ~.eference to the following detailed description of the illustration will make full appreciation of the drawings and our invention possible.
Referring now to Fig» ~., a security document 10 is illustrated comprising a substrate ~.2 which has been coated with a color-forming composition 14 including an insulating material 15 and then coated with a toner-adhesion enhancing coating 16, which also preferably includes the insulating material 15.
Fig. 2 illustrates an embodiment of the invention in which the color-forming composition has been initially printed as covert warning words 32 on the entire surface of the document, ire this instance the warning phrase VOID. The words formed by the coating 32 are virtually invisible because of the initially colorless state of the dye, but become visible when exposed to a solvent, or if subjected to abrasion or. heat sufficient to cause the reactants to rear~t.
Fig. 3 illustrates an embodiment of the invention in which the color-forming composition has beerx coated on only certain portions of the document. As shown, the monetary amount portions of the document have been printed with the composition in the form of warning indicia 32 while the 7_eft hand portion of the document has been printed with authentication indicia 34. If alteratioxa of the coated portion of the document is attempted such as with the use of a solvent as shown in area 22, the warning words become visible.
The use of a solvent w:~ll either dissolve the leuco dye and/or the color developer which activates the ~..euco dye and develops a visible color. Likewise, if the document is exposed to heat or abrasion in the areas containing the authentication or.
warning indicia, the color-forming compositiorx will activate.
In order that the invention may be more readily understood, reference is made to the following examples, which are intended to be illustrative of the invention, but are not intended to be limiting in scope.
Example 1 A color-forming composition was prepared by combining the following materials:
Weight 20% polyvinyl alcohol solution 7 starch solution 20 Chlorostain ORS 9 50% Sulfonyl diphenolz 25 Water 14 50% black 305 dye3 10 Rhopaque HP 1055 15 lamino benzyl thiazol from Bayer Zcalor developer from Alfa Chemical.
3color former from Nagase America 'polystyrene spheres from Rahm and Haas The coating was spot coated by a. flexor~raphic printer with a 5.6 BCM anilox roll to prova~de a dry coat weight of 0.5 lbs. /1300ft' (1.9 g/m2) . The resulting dac~,unent exhibited solvent and hypochlorite sensitivity to ethyl acetate, ethyl alcohol, acetone, isopropyl alc:ahol and bleach. The document successfully passed through an Epsanklaser printer (Action Laser 1500) and a high speed Xerox~4050 .Laser printer with no premature color development.
* Trademark _~~_ Exam~rle 2 A toner adhesion-enhancing coating was prepared by combining the following materials;
Weight %
LASERLOCK~''1 50 Water 15 Rhopaque HP 10552 30 Isopropyl Alcohol 5 1 toner adhesion-enhancing coating from Standard Register. (U. S.
Patent No. 5,045,426) polystyrene spheres from Rohm ~ Haas The color-forming composition prepared in Example 1 was spot coated onto a substrate by a flexographic printex° with a 5.6 BCM anilox roll to provide a dry coat weight of 0.5 lbs./1300 ft.z (1.9 g/m~). The toner adhesion-enhancing coating prepared above was them applied to Ghe substrate as a full coat using a flexographic printer with a 200 line, 5.6 BCM anilox roll. The resulting document ex.~libited solvent and hypochlorite sensitivity to ethyl acetate, ethyl alcohol, acetone, isopropyl alcohol and bleach. The document successfully passed through an Epson laser printer (Action Laser 1500) and a Xerox high speed 4050 laser printer with no premature color development.
While certain representative embodiments and details have been shown for purposes of illustrating the invention, it+
will be apparent to those skilled in the art: that various changes in the methods and apparatus disclosed herein may be made without departing from the scope of th~:~ .invention, which is defined in the appended claims.
The present invention relates to a heat resistant security document containing at least one composition which activates to produce a color upon the application of a solvent, heat or abrasion. More particularly, the invention relates to a. security document having an insulating material blended with. such an activatable composition which allows the document to be passed through heated non-impact printing devices such as laser printers without the problem of premature color development. The c:omposi..tion~;s) may be used to provide authentication and/or security features on ;~.
document.
Security documents are printed on a wide variety caf commercial printing devices. Traditional mechanical impact printers have been typically been used ire. the past for printing information ors security documents such as checks.
The inks used with most impact printers adhere well to a document due to the par. tial penetrs.tior~ of the ink i.nt~.~ the surface of the document substrate. In addition, dyes or other coatings may be applied to the documents to aid ixi the prevention of fraudulent alteration of security documents.
For example, U.S. Patent No. 5,209,51.5 teaches a solvent and/or pressure sensitive coating Comprising a mixture of a color former and a color developer may be used to produce covert images on a security doc~zment. Lf attempted alteration of such a document is made by the application of solvents and/or pressure, the color former and/or color developer dissolve and react t:o form a visible image on the substrate, providing easy detection of the attempted alteration.
However, with the advance of microcomputer technology, a number of faster printing methods have been developed to take advantage of the high-speed printing output: which is mcaw possible. Laser printers are an example of nonimpact printers which are faster, quieter, and more reliable than impart -printers. Such printers operate by fusing toner images onto a substrate by passing the substrate through s. pair of rolls which apply both heat and pressure.
However, such printers have significant limitations which have prevented their wide use in printing documents such as checks and other security documents. Une limitation is the inability to achieve satisfactory toner bonding on a large variety of paper products used to make such documents. Because of the lack of strong adherence of toner to paper, documents printed using such printers may be subject to deliberate alteration by counterfeiters, forgers, and the like.
Toner adhesion-enhancing coat~..ngs have been developed which improve the adhesion of. toner to the documents. For example, U.S. Patent No. 5,0~5,42~ to Maierson et al describes a polymeric toner adhesion-enha~xcing composition for use on documents printed with noncarztact ~>rinting devices. However, documents containing such toner adhesionMenhancing coatings may still be subject to alteration by other methods as the solvent sensitive coatings used in the art as described above cannot withstand passage through a laser printer. This is due to the high temperature of the toner fuser callers which will melt the dye and/or developer and cause premature color.
development on the documents.
accordingly, there is stir. a need in the art for a security document which may be printed using a high-speed printing device such as a laser printer without the problem of premature coloration and which has security features which can provide authentication of the document and/or indicate attempted alterations of the document.
The present invention meets that need by providing an insulating material for use on security dacuznents wr~ich, in combination with a color-forming composition and/or a toner adhesion-enhancing composition, provides heat resistance to prevent premature coloration when the documents axe passed through a printing device such as a laser printer. The:
security document may be used to provide an authentication feature and/or an indication of attempted alterations from the use of solvents, heat, or abrasion.
According to one aspect of the present invention, a security document is provided which is resistant to premature coloration by heat. The document comprises a substrate having first and second major surfaces with at least a portion of one of the major surfaces having thereon a composition which activates to produce a color upon the application of a solvent, heat sufficient to cause the composition to melt:, or abrasion. The color-forming composition also includes an insulating material to provide heat resistance when the document is passed through a noncontact printing devicE= such as a laser printer.
By resistant to premature coloration by heat, it is meant that the composition ors the document will. not activate to form a color when exposed to temperatures of about 450 to 475°F
1232.22 to 246.11°C) for a period of about 0.5 seconds or less, which typically occurs when a document is passed through a noncontact printing device such as a laser printer.
Accordingly, while the document will not activate prematurely when exposed to such a source of heat, it rnay still be activated when exposed to heat for a time and temperature which is sufficient to cause the reactants in the color_-forming composition to melt, i.e., at a temperature of about 400°F {204.44°C) for at least about ~. second.
The color-forming composition preferably comprises a mixture of initially colorless color formers and color developers, and in a. preferred embodiment, includes a binder.
Preferably, the color former comprises a leuco dye having a melting point of greater than about 150°C. The color developer preferably camprises a phenolic resin having a melting point of greater than about 150°C. "fhe composition is preferably applied to the substrate to provide a dry coating weight of between about 0.4 and 0.5 lbs./1300 f12 CA 02278145 2003-06-02 "
(1.52 to 1.9 g/m2) (17 x 22", 500 sheet ream). The composition may be printed on one or more areas of the substrate and on one or both sides of the substrate. The composition may be printed in the form of covert warning indicia such as the ward "VOID" or any other symbol which would alert;: a user to an attempted alteration.
Alternatively, or in addition, the composition may be printed on the substrate in the form of covert authentication indicia such as the words "VALID" or "AUTHENTIC" or any other symbol which would indicate to a user the genuineness of the document. In one embodiment, the warning irxdicia are printed on one surface of the substrate, while the authentication indicia are printed on the opposite surface. In another embodiment, the warning and authentication indicia are interspersed. on the swine surface of the document .
The insulating material included in the color-forming composition functions to prevent heat transfer from the fuser rolls of a laser printer to the composition, thus preventing melting of the color fc~rrner or color developer. which would ZO cause premature coloration on the substrate. The insulating material may be inorganic ox organa.c and may comprise ho7.low or solid polymeric particles. 'I'he partx.cles may be .in the form of hollow tubes or spheres. A preferred insulating material comprises hollow polymeric spheres of polystyrene.
The insulating material preferably comprises from about 10 to 20% by weight of the cc~lar-forming composition.
In a preferred embodiment of the invention, the security document further includes a toner adhesion-enhancing composition which overlies the color-forming composition, where the toner adhesion enhancing composition comprises a polymeric toner adhesion-enhancing coating and an insulating material. The toner adhesion-enhancing coating provides improved adhesion of toner particles to the security document when printed with a laser or other noncontact printer, while the insulating material. functions to prevent heat transfer to the color-forming composition underneath. Preferably, the polymeric toner adhesion-enhancing coating comprises a.
synthetic or natural latex, such as a carboxylated styrene-butadiene latex or styrene-butadiene latex.
The insulating material preferably comprises from about 20 to 40% by weight of the toner adhesion-ezxhancing composition, and preferably comprises hollow polymeric spheres comprised of polystyrene. The toner adhesion-enhancing composition is preferably applied to the substrate to provide a dry coating weight of 0.25 to 0.35 lbs./5300 ft.2 (0.95 to 1.33 g/mz) .
When the security document of the present invention is passed through a laser printer or other heated non-impact printing device, the color-farming composition is not activated due to the presence of the insulating material in the composition. Horaever, if the document is exposed to any number of common solvents, the solvent will penetrate the toner adhesion-enhancing layer on the substrate and the composition will activate such that the warning and/or authentication indicia will became visib~.e an the substrate.
The indicia will also become visible if the document is exposed to heat for a time which is sufficient to melt the color forming and color developing reactants in the composition, or if the document is subjected t:o abrasion., Accordingly, it is a feature of the present invention to provide a security document printed with a color-forming composition containing an insulating material which allows security documents to be printed using heated non-impact printing devices such as laser printers without premature color development on the document. zt is a further feature of the invention to provide a toner adhesioza-enhancing composition including an insulating material. therein which may be coated over the color-forming compasit,ion. These, .and other features and advantages of the present invention will ' CA 02278145 2003-06-02 -~..
become apparent from the following detailed description, the accompanying drawings, and the appended claims.
In order that the invention may be more readily understood, reference will now be made by example to the accompanying drawings, in which Fig. 1 is a fragmentary sectional view of a document substrate containing a color-forming composition and a. toner adhesion enhancing composition which include an insulating material; Fig. 2 is a front elevation view of a security document containing the color-forming composition initially printed as covert warning indicia; and Fig. 3 is a front elevation view of a security document including both authentication and warning indicia and illustrating the appearance of the warning indicia after alteration has been attempted.
The use of an insulating material in combination with a color-forming composition and/or a toner adhesion-enhancing coating provides the capability to use high speed noncontact printing devices su~.h as laser printers for printing a variety of security documents such as checks, negotiable certificates, transcripts, or other documents of value or documents which evidence value while still prozYiding a means of detecting fraudulent alteration of such documents.
The insulating material used in the present invention is in particulate form and preferably comprises small diameter polymeric particles, and most preferably comprises hollow polymeric spheres of polystyrene, The particles may take the form of hollow tubes ox spheres and may have a diameter of approximately 0.5 to 1 ~.m. ~1 preferred insulating material is Rhopaque HP 1055, available from Rohm and Haas. Other suitable insulating materials include solid spheres of polystyrene available from Dow Ohemical ~:ompany under the designation Dow 662x. Whether present in the color--forming composition, the toner-adhesion enhancing composition, or both, the insulating material functions too prevent, or at:
_7_, least retard, heat transfer to the color former and color developer in the color forming composition. Specifically, the insulating material prevents the leuco dye and color developer from reaching their melting points when exposed to the high temperatures generated from the heated fuser rollers of a laser printer, i.e. , from about. 4~Cf° to 4'~5°F
(232.22°C to 246.11°C).
The insulating material may be combined with the other components in the color-form~.ng~ composita.on and preferab7_y 14 comprises from about 10% to 20% by weigh. of the color-farming composition.
Suitable color forming dyes for use in the color-forming composition include any of the initially colon°less dye precursors conventianally used in this art and include, but 15, are not limited to, colorless leuco dye precursors such as crystal violet lactone, ben~oyl leuco methylene blue, :i.ndolyl red, malachite green lactone, 8'-methoxybenzoindoline spiropyran, and rhodamine lactone.
Suitable color developers for use in the color-forming 20 composition include, but are not limited to, phenolic :c-esins such as acetylated phenolic resins, sal~..c.ylic acid-modified phenolic resins, and novolac-type phenol.ic resins. ~1 preferred phenolic z°esin is 4,4-sulfony~.. diphenol. Both the color formers and color developers used should preferably have 25 a melting point of greater than 150°C to avoir~. premature coloration.
Preferably, the color-forming composition includes one or more binders which function to keep the composition in proper suspension for printinr~. Suitable binders include polyvinyl 30 alcohol or a grafted starch solution. Preferred for use is a grafted starch solution as it enhances the duality and color development of the words, indicia, or patterns activated on the document substrate.
As can be seen in the drawing figures, the color-forming 35 composition may be fully coated onto substantially the entire ...
surface of the substrate, spot-coated onto only one or more predetermined areas of the substrate, or printed as wards, symbols, or patterns. The color-farming composition may be printed as covert authenti.catian indicia, warning indi.cia, or a combination of both, For example, in embodiments where it is desirable to prevent fraudulent alteration of a document, covert indicia such as the words "VOID" or other images may be printed on the document. In embodiments where it i.s desirable t:o provide an authentication feature, words such as "VALID'", "AUTHENTIC", or other words, symbols, patterns, images or designs, such as company logos or geometric shapes nnay be printed on the document.
It should be appreciated that many different combinations for placement of the color-forming composition on a security document are possib:Le and are with:i.n the scope of this invention. For example, the composition may be printed as covert warning or authentication indicia on the ent.ire~
document, or only in certain areas such as ~~he area in. which a signature or monetary value is present. It may desirable far some embodiments to include authentication w.ndica on one portion of a document and covert warning .indicia on another portion of a document. For example, on a. security document such as a check, warning indicia may be printed in the areas containing monetary amounts while authentication indicia may be printed an other areas of the check whictl would not.
interfere with check processing. Alternatively, warning indici.a could be printed an one side of a d~>cvment and authentication indicia printed an the other side of the document.
In still other embodiments, it may be desirable to combine the authentication and warning indicia together as an interspersed pattern an a document such as VOID<>AUTHENTIC<>VOID<>AU'I'HENTIC etc. Whether the col.ar-forming composition is printed as warning indicia, . authentication indicia, or a combination thereof, the words or images should be printed so that they can easily be detected upon activation of the composition. Preferably, the color-forming composition is printed onto a security document by S flexographic printing. The composition is preferably applied to provide a dry coating weight. of between about 0.4 and 0.5 lbs/1300 ftz (1.52 to 1~.9 g/m2) .
The resulting security document will provide authentication or show attempted alteration by the use of most oxygenated solvents including alcohols, ketanes, esters and ethers. To increase the range of sensitivity of the color-forming compositions a hypochlorite sensitive compound such as amino benzyl thiozol (available from Bayer as Chlorostain OR*) may also be included. This compound provides protection against the use of hypochlorite agents wkxich could damage the color formers and/or valor developers and leave the document susceptible to alteration by solvents.
In embodiments where both warning indicia and authentication indicia are present on a document, the color forming composition used to print t:he warning indicia may comprise a different composition than the solar forming composition used to print the authentication indicia. For example, it may be desirable to have different compositions for the warning indicia and authentication indicia so that they may be activated by different solvents, i.e., the warning indicia could be printed with a color-forming composition which is activatable by a wide variety of solvents while the authentication indicia could be printed with a color-farming composition which is activatable by only one type of solvent.
The security document of the present invention will also provide authentication or show attempted al~:eration by the application of direct heat from a suitable heat source which causes the color forming and solar developing reactants in the color-forming composition to melt and act":ivate. The calar-forming composition will also activate by abrasion such as * Trademark -1f~-vigorous rubbing. While not wishing to be bound by any particular theory, it is believed that the insulating material migrates to the surface of the printed indicia, and. that vigorous rubbing removes the insulating surface layer on the document, allowing the color-forming reactants to come into intimate contact and/or become heated by friction such that they react.
In embodiments where a toner adhesion-enhancing composition is applied over the color-forming composition, the toner adhesion-enhancing composition is preferably applied to provide a dry coating weight of between. abaut 0.25 and 0.35 lbs. j1300 ft.z (.95 and 1.33 g/rn~) X17 x 22" ~ 500 sheet: ream) .
Suitable toner adhesion-enhancing compositions are taught in U.S. Patent No. 5,045,426 to Maiersan et al, U.S. Patent No.
5,017,416 to Imperial et al, arad published International apple.
No. WO 90/13064. A pre~~erred toner adhe~:~...on-enhanf~ing wompo-sition comprises a .natural or syrlt~net~c :iat:E~x such as ~_~arboxy-lated styrene-butadien~~~ latexes c~~- ~tya~tyrle-L:~ut:adiene l;~texes .
Carboxylated styrene-butadiene latexes suitable for use :in the present invention are available: from the Daw Chemical Company under the designations 615NA, 620NA, and 722NA.
The toner adhesion-enhancing composition preferably further includes from about 20~ to 40% by wez.ght of the insulating material, which provides further insulation to the color-forming composition underneath. ''fhe toner adhesion-enhancing coating is preferably applied to the substrate as an aqueous dispersion, and is preferably applied over substantially the entire surface of' the substrate to yield a dry coat weight of 0.3 to 0.4 1b/1300 ft.' (1.14 to 1..52 g/m2).
With reference to the drawings, it. must:;. be appreciated that Patent Of f ice .requirements f ax' sol ~.~3 black 1 ine drawings on a white surface make illustration of some of the subtleties of our invention re:Lating to different colors difficult by the required Patent Office drawings alone. ~.eference to the following detailed description of the illustration will make full appreciation of the drawings and our invention possible.
Referring now to Fig» ~., a security document 10 is illustrated comprising a substrate ~.2 which has been coated with a color-forming composition 14 including an insulating material 15 and then coated with a toner-adhesion enhancing coating 16, which also preferably includes the insulating material 15.
Fig. 2 illustrates an embodiment of the invention in which the color-forming composition has been initially printed as covert warning words 32 on the entire surface of the document, ire this instance the warning phrase VOID. The words formed by the coating 32 are virtually invisible because of the initially colorless state of the dye, but become visible when exposed to a solvent, or if subjected to abrasion or. heat sufficient to cause the reactants to rear~t.
Fig. 3 illustrates an embodiment of the invention in which the color-forming composition has beerx coated on only certain portions of the document. As shown, the monetary amount portions of the document have been printed with the composition in the form of warning indicia 32 while the 7_eft hand portion of the document has been printed with authentication indicia 34. If alteratioxa of the coated portion of the document is attempted such as with the use of a solvent as shown in area 22, the warning words become visible.
The use of a solvent w:~ll either dissolve the leuco dye and/or the color developer which activates the ~..euco dye and develops a visible color. Likewise, if the document is exposed to heat or abrasion in the areas containing the authentication or.
warning indicia, the color-forming compositiorx will activate.
In order that the invention may be more readily understood, reference is made to the following examples, which are intended to be illustrative of the invention, but are not intended to be limiting in scope.
Example 1 A color-forming composition was prepared by combining the following materials:
Weight 20% polyvinyl alcohol solution 7 starch solution 20 Chlorostain ORS 9 50% Sulfonyl diphenolz 25 Water 14 50% black 305 dye3 10 Rhopaque HP 1055 15 lamino benzyl thiazol from Bayer Zcalor developer from Alfa Chemical.
3color former from Nagase America 'polystyrene spheres from Rahm and Haas The coating was spot coated by a. flexor~raphic printer with a 5.6 BCM anilox roll to prova~de a dry coat weight of 0.5 lbs. /1300ft' (1.9 g/m2) . The resulting dac~,unent exhibited solvent and hypochlorite sensitivity to ethyl acetate, ethyl alcohol, acetone, isopropyl alc:ahol and bleach. The document successfully passed through an Epsanklaser printer (Action Laser 1500) and a high speed Xerox~4050 .Laser printer with no premature color development.
* Trademark _~~_ Exam~rle 2 A toner adhesion-enhancing coating was prepared by combining the following materials;
Weight %
LASERLOCK~''1 50 Water 15 Rhopaque HP 10552 30 Isopropyl Alcohol 5 1 toner adhesion-enhancing coating from Standard Register. (U. S.
Patent No. 5,045,426) polystyrene spheres from Rohm ~ Haas The color-forming composition prepared in Example 1 was spot coated onto a substrate by a flexographic printex° with a 5.6 BCM anilox roll to provide a dry coat weight of 0.5 lbs./1300 ft.z (1.9 g/m~). The toner adhesion-enhancing coating prepared above was them applied to Ghe substrate as a full coat using a flexographic printer with a 200 line, 5.6 BCM anilox roll. The resulting document ex.~libited solvent and hypochlorite sensitivity to ethyl acetate, ethyl alcohol, acetone, isopropyl alcohol and bleach. The document successfully passed through an Epson laser printer (Action Laser 1500) and a Xerox high speed 4050 laser printer with no premature color development.
While certain representative embodiments and details have been shown for purposes of illustrating the invention, it+
will be apparent to those skilled in the art: that various changes in the methods and apparatus disclosed herein may be made without departing from the scope of th~:~ .invention, which is defined in the appended claims.
Claims (17)
1. A security document which is resistant to premature coloration by heat comprising a substrate having first and second major surface, at least a portion of one of said major surfaces having thereon a composition comprising an initially color-free color former and a color developer which composition activates to produce a color upon application of one of a solvent, heat sufficient to cause said composition to melt, and abrasion, said composition including an insulating material which prevents premature melting of said composition where said document is passed through a non-impact printing device.
2. The security document of claim 1 in which said composition is applied to provide a dry coating weight of between about 0.4 and 0.5 lbs/1300 ft.2. (1.52 to 1.9 g/m2).
3. The security document of claim 1 in which said color former comprises a leuco dye having a melting point of greater than about 150°C.
4. The security document of claim 1 which said color developer comprises a phenolic resin having a melting point of greater than 150°C.
5. The security document of claim 1 in which said composition is printed on said substrate as covert authentication indicia.
6. The security document of claim 1 in which said composition is printed on said substrate as covert authentication indicia.
7. The security document of claim 1 in which said insulating material comprises polymeric spheres.
8. The security document of claim 7 in which said polymeric spheres are comprised of polystyrene.
9. The security document of claim 1 further including a toner adhesion-enhancing composition overlying said composition, said toner adhesion enhancing composition comprising a polymeric toner adhesion-enhancing coating and an insulating material.
10. The security document of claim 9 in which said toner adhesion enhancing composition comprises a latex.
11. The security document of claim 9 in which said toner adhesion-enhancing composition is applied to provide a dry coating weight of between about 0.25 and 0.35 lbs./1300 ft.2 (0.95 to 1.33 g/m2).
12. The security document of claim 9 in which said insulating material in said toner adhesion enhancing composition comprises polymeric spheres.
13. The security document of claim 9 in which said hollow polymeric spheres comprise polystyrene.
14. The security document of claim 9 in which said polymeric toner adhesion-enhancing composition comprises a copolymer of styrene and acrylic acid.
15. The security document of claim 9 in which said composition is printed on said substrate as covert warning indicia.
16. The security document of claim 9 in which said composition is printed on said substrate as covert authentication indicia.
17. The security document of claim 1 in which said composition is printed on said substrate as covert warning indicia and authentication indicia.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/790,198 US5912205A (en) | 1997-01-30 | 1997-01-30 | Heat resistant security document |
| US08/790,198 | 1997-01-30 | ||
| PCT/US1998/000405 WO1998033654A1 (en) | 1997-01-30 | 1998-01-12 | Heat resistant security document |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2278145A1 CA2278145A1 (en) | 1998-08-06 |
| CA2278145C true CA2278145C (en) | 2004-08-10 |
Family
ID=25149924
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002278145A Expired - Fee Related CA2278145C (en) | 1997-01-30 | 1998-01-12 | Heat resistant security document |
Country Status (11)
| Country | Link |
|---|---|
| US (1) | US5912205A (en) |
| EP (1) | EP0956202A1 (en) |
| JP (1) | JP2002500575A (en) |
| AU (1) | AU729954B2 (en) |
| BR (1) | BR9806938A (en) |
| CA (1) | CA2278145C (en) |
| CO (1) | CO4930298A1 (en) |
| ID (1) | ID23147A (en) |
| NZ (1) | NZ336895A (en) |
| WO (1) | WO1998033654A1 (en) |
| ZA (1) | ZA98537B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6209923B1 (en) * | 1999-04-14 | 2001-04-03 | The Standard Register Company | Security document and authentication scheme |
| US6562755B1 (en) * | 2000-10-31 | 2003-05-13 | Ncr Corporation | Thermal paper with security features |
| US6783991B1 (en) * | 2002-02-06 | 2004-08-31 | The Standard Register Company | Reversible and reusable authentication system for secure documents |
| US20050064151A1 (en) * | 2003-09-18 | 2005-03-24 | Rajendra Mehta | Ink jet printable security document |
| US7645719B2 (en) * | 2004-10-13 | 2010-01-12 | Ncr Corporation | Thermal paper with security features |
| ITMI20050744A1 (en) * | 2005-04-26 | 2006-10-27 | Gruppo Cordenons Spa | PATENTED PAPER MATERIAL AUTHENTICABLE IN PARTICULAR FOR LABELING AND PACKAGING AND ITS PROCESS OF MANUFACTURING |
| US8367580B2 (en) * | 2006-03-07 | 2013-02-05 | Ncr Corporation | Dual-sided thermal security features |
| US7777770B2 (en) | 2005-12-08 | 2010-08-17 | Ncr Corporation | Dual-sided two-ply direct thermal image element |
| DE102007006059A1 (en) * | 2007-02-02 | 2008-08-07 | Peter Dr. Schneider | Design for producing thermal paper, has layer, which is applied to thermal layer, where acid component is introduced into auxiliary layer with acid color developer of thermal layer |
| ITFI20090113A1 (en) * | 2009-05-20 | 2010-11-21 | Perini Fabio Spa | "METHOD FOR THE COLORING OF A TAPE OF CELLULOSIC MATERIAL, LINE FOR THE IMPLEMENTATION OF THIS METHOD AND PRODUCT SO" OBTAINED " |
| US10882347B1 (en) * | 2019-09-16 | 2021-01-05 | Xerox Corporation | Security marks based on print job image |
| US11014391B2 (en) | 2019-09-16 | 2021-05-25 | Xerox Corporation | Security marks based on print job image with uniform printed background |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE661981A (en) * | 1964-04-03 | |||
| US4046404A (en) * | 1976-11-26 | 1977-09-06 | Xerox Corporation | Carbonless paper for use in electrostatographic copiers |
| FR2491514A1 (en) * | 1980-10-08 | 1982-04-09 | Du Pin Cellulose | COATED PAPERS AND CARDBOARDS AND MANUFACTURING METHOD |
| JPS6242878A (en) * | 1985-08-10 | 1987-02-24 | Ricoh Co Ltd | Thermal recording material |
| US5045426A (en) * | 1989-06-21 | 1991-09-03 | The Standard Register Company | Toner adhesion-enhancing coating for security documents |
| US5017416A (en) * | 1989-10-17 | 1991-05-21 | International Paper Company | Paper for use in ion deposition printing |
| US5209515A (en) * | 1991-02-08 | 1993-05-11 | The Standard Register Company | Solvent and/or pressure sensitive security document |
| US5250492A (en) * | 1991-03-07 | 1993-10-05 | The Standard Register Company | Coatings for use with business forms, security documents, or safety paper |
| US5284816A (en) * | 1992-11-19 | 1994-02-08 | Eastman Kodak Company | Two-sided thermal printing system |
| US5427415A (en) * | 1992-12-09 | 1995-06-27 | Wallace Computer Services, Inc. | Heat sensitive system and use thereof |
| US5342649A (en) * | 1993-01-15 | 1994-08-30 | International Paper Company | Coated base paper for use in the manufacture of low heat thermal printing paper |
| US5595590A (en) * | 1995-05-31 | 1997-01-21 | Nocopi Technologies, Inc. | Method and compositions for authenticating a product or document |
-
1997
- 1997-01-30 US US08/790,198 patent/US5912205A/en not_active Expired - Lifetime
-
1998
- 1998-01-12 EP EP98902454A patent/EP0956202A1/en not_active Withdrawn
- 1998-01-12 CA CA002278145A patent/CA2278145C/en not_active Expired - Fee Related
- 1998-01-12 WO PCT/US1998/000405 patent/WO1998033654A1/en not_active Application Discontinuation
- 1998-01-12 JP JP53290198A patent/JP2002500575A/en active Pending
- 1998-01-12 BR BR9806938-1A patent/BR9806938A/en not_active IP Right Cessation
- 1998-01-12 AU AU59114/98A patent/AU729954B2/en not_active Ceased
- 1998-01-12 ID IDW990784A patent/ID23147A/en unknown
- 1998-01-12 NZ NZ336895A patent/NZ336895A/en unknown
- 1998-01-22 ZA ZA98537A patent/ZA98537B/en unknown
- 1998-01-28 CO CO98003994A patent/CO4930298A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JP2002500575A (en) | 2002-01-08 |
| CO4930298A1 (en) | 2000-06-27 |
| EP0956202A1 (en) | 1999-11-17 |
| NZ336895A (en) | 2001-08-31 |
| WO1998033654A1 (en) | 1998-08-06 |
| ZA98537B (en) | 1998-07-29 |
| ID23147A (en) | 2000-03-23 |
| AU5911498A (en) | 1998-08-25 |
| AU729954B2 (en) | 2001-02-15 |
| BR9806938A (en) | 2000-03-28 |
| US5912205A (en) | 1999-06-15 |
| CA2278145A1 (en) | 1998-08-06 |
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| EEER | Examination request | ||
| MKLA | Lapsed |