CA2278895A1 - Printed document with security layer - Google Patents

Abstract

A printed document including a non-foil containing substrate, data printed over at least a portion of the substrate, and at least one security layer applied above, below or both above and below the data, said at least one security layer including a composition which, upon exposure to undesirable contact by an attacking material which can expose the data, undergoes a change of a property which can be visually observed.

Description

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Field Of The Invention The present invention is generally directed to printed documents such as lottery tickets which contain at least one security layer for detecting unauthorized attempts at reading information thereon through the employment of a composition which includes a resin having basic or acidic functional groups and a pH sensitive indicator.
The printed document includes at least one layer containing the composition which when exposed to certain chemicals will initiate a visible change in property which can be visually observed.
Background Of The Invention The present invention concerns printed documents in general. A primary field of use is in the manufacture and use of scratch-off or scratch lottery tickets. However, it will be appreciated that the present invention is not limited to scratch lottery tickets and can include game cards, security documents, banknotes and the like.
In the field of scratch lottery tickets it is necessary to conceal the secure game data information, upon which the outcome of the game depends, from the user until it is removed in accordance with the rules of the game. In the past, this has been done by printing the secure game data information on a foil-lined cardstock and overprinting ARK:jsg070799/1591311.APP
the secure game data information with a scratch-off or scratch removable layer. The advantages of using foil lined cardstock include its opacity which prevents observation of the secure game data information by °candling". This unauthorized procedure includes the shining of a bright light through the card to reveal the game data information in silhouette. The foil also provides a barrier between the cardstock and the game data information which guards against delamination of the cardstock and subsequent "leaching" of the game data information by the use of an °attacking material" such as a solvent. However, such foil-lined scratch lottery tickets have the disadvantage that they are not easily recyclable and hence must be discarded after use, typically into a landfill.
Due to the rising popularity of scratch lottery tickets and similar type of printed documents, and the recent increase in the importance of environmental issues, there are now significant concerns regarding the environmental effects of disposal of large amounts of these printed documents into landfills. As a result, the production and use of a recyclable scratch lottery ticket having similar security features to foil tickets without - the environmentally sensitive disadvantages is highly desirable.
Attempts have been made to replicate the beneficial properties of foil, for example, resistance to bleeding and solvent attack, and opacity to light, by printing confusion patterns, black panels and the like onto standard non-foil containing cardstock. These attempts have resulted in scratch lottery tickets including numerous ARK:jsg070799/1591311.APP
printing layers which tend to increase the number of printing stations needed to apply the layers, increasing the cost of such product and causing other structural issues like inter-coat adhesion problems resulting in the chipping or lifting of these layers.
Furthermore, the combination of black layers for opacity with white overiayers for legibility tends to result in a grayish blue background which reduces contrast of the game data information and undesirably limits the graphic designs available for scratch lottery tickets.
Furthermore, scratch lottery tickets may also, from time to time, suffer from the disadvantage that it is possible to delaminate or split the cardstock in an unauthorized manner to facilitate solvent bleeding or leeching of the secured game data information through the cardstock.
Accordingly, there remains a need for scratch lottery tickets and other printed documents, especially of the type having a scratch removable coating, and a method of producing such documents which prevents optical penetration and chemical - penetration, is environmentally friendly, and is capable of reproduction at an acceptable cost. Desirably, such scratch lottery tickets should be suitable for production by use of a flexographic printing process and preferably using a multi-color overprinting process as disclosed in Australian Patent Application No. 61342/96 and United States Patent Nos. 5,704,647 and 5,803,504, each of which is incorporated herein by reference.

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Summar)r Of The Invention The present invention is generally directed to a printed document in which at least one security layer is provided so that when the printed document is attacked by a material such as a solvent, a change in property will appear in the ticket which can be visually observed. The visible observation of the change of property is indicative that the printed document has been tampered with.
In one aspect of the present invention, there is provided a printed document comprising:
a) a non-foil containing substrate;
b) data printed over at least a portion of the substrate; and c) at least one security layer applied above, below or both above and below the data, said at least one security layer comprising a composition which, upon exposure to undesirable contact with an attacking material which can expose the data, undergoes a change of a property which can be visually observed.
The present invention is also directed to a composition which can be employed in the printed document and methods of detecting tampering of the printed document by the application of the composition on the printed document.

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Brief Description Of The Drawings The following drawings in which like reference characters indicate like parts are illustrative of embodiments of the invention and are not intended to limit the invention as encompassed by the claims forming part of the application.
Figure 1 is an exploded perspective view of a lottery ticket in accordance with the present invention with a security layer beneath the game data layer;
Figure 2 is an exploded perspective view of a lottery ticket employing a security layer both below and above the game data layer; and Figure 3 is an exploded view of a lottery ticket including a security layer above the scratch-off layer.
Detailed Description Of The Invention The present invention is generally directed to a printed document which employs at least one security layer which includes a composition, which upon exposure to contact by an attacking material such as a solvent undergoes a change of property which can be visually observed. This change in property is indicative of an attempt to tamper with the printed document.

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Referring to Figure 1, there is shown an embodiment of the invention in the form of a lottery ticket. The lottery ticket shown generally by the numeral 30 includes a metallic foil-free substrate 1, preferably composed of paper or cardboard.
Optionally, a series of benday lines 2 are printed on one side of the substrate 1 while any desired game instructions or advertising are printed on the other side of the substrate. The purpose of the benday lines 2 are to protect against cutting and pasting sections of the lottery ticket together. In particular, the benday lines 2 are intended to prevent the removal of a section of one lottery ticket and replacement with a section of another lottery ticket to produce an unauthorized winning lottery ticket.
On top of the benday lines 2 is printed at least one security layer 3 in accordance with the present invention and as more fully described below.
The lottery ticket 30 has a layer of game data 4 which in Figure 1 is shown above the security layer 3. As described in detail hereinafter, the position of the security layer may be above the game data layer 4 andlor above the scratch-off layer of the lottery - 15 - ticket.
The lottery ticket 30 may include at least one sealed coat 5 which in turn is overprinted by a layer 6 of a release varnish to protect the game data from scratching and the like. To prevent the unauthorized visual observation of the game data 4, a series of scratch removable opaque layers 7-11 are applied over the release varnish ARK:jsg070799/1591311.APP
layer 6. In accordance with typical lottery tickets, there is provided one or more graphic overprinting layers (four such layers are shown by reference numerals 12-15) over the scratch removable layers 7-11. The graphic overprinting layers 12-15 can be produced as described in U.S. Patent Nos. 5,704,647 and 5,803,504.
The graphic overprinting layers can include simple or complex graphic designs, rules of the game and other information which may be relevant to the purpose of the lottery ticket. Finally, a layer 16 of a gloss varnish is applied over the overprinting layers 12-15 for protection purposes.
The security layer 3 as previously described in accordance with the present invention prevents unauthorized exposure of the game data information 4 until the user is authorized to expose the game data in accordance with the rules of the game. The security layer 3 is designed to prevent unauthorized viewing of the game data layer 4 by splitting or delaminating the card to facilitate solvent bleeding or leeching of the game data through the cardstock substrate 1. Solvents which can be used to facilitate - such bleeding or leeching have typically included household cleaners, alcohols and other liquid materials typically having a basic pH (i.e. a pH of at least 8.0). In accordance with the present invention, the security layer 3 undergoes a change in property when in the presence of solvents and related materials (referred to herein as "attacking materials") which tend to bleed or leech the game data layer 4. In a preferred form of the invention, the security layer 4 changes color which can be visually observed ARK:jsg070799/1591311.APP
by a lottery ticket agent or other person in charge with responsibility of validating a lottery ticket.
The security layer 3 is comprised of a composition which includes a resin and a pH sensitive indicator. The composition must be capable of changing a property (e.g.
undergoing a color change) upon contact with the attacking material such as a solvent.
Since most attacking materials are either basic or acidic, a composition containing a pH
sensitive indicator is preferred for the security layer.
The resin material of the composition is required to have acidic or basic functional groups. The resin provides the composition with an acidic or basic character which enables the pH sensitive indicator to change color when exposed to a basic or acidic attacking material. The change in color occurs if the attacking material is basic and the resin has acidic functional groups or if the attacking material is acidic and the resin has basic functional groups. In the construction of a lottery ticket or other type of printed document, the security layer thereon must exhibit either acidic or basic - character.
In a preferred form of the invention, the security layer includes a resin having acidic functional groups and an especially preferred resin is a polymer composed of acrylic acid groups. When such resins are applied to a lottery ticket and dried they exhibit acidic properties. Typical examples of polymers with acrylic acidic groups _g_ ARK:jsg070799/1591311.APP
include copolymers of styrene 2-ethyl hexyl acrylate and methyl methacrylate with acrylic and/or carboxylic acid functional groups.
A resin having an acidic character when combined with a pH sensitive indicator will produce a change in color when contacted with a basic attacking material such as S many household solvents as described above. The change in color is indicative of the unauthorized presence of such attacking materials which are used to expose the game data layer 4 in an unauthorized manner.
Examples of pH sensitive indicators for use in the present invention and their range of pH for producing a color change are shown in Table 1.
Table 1 PRODUCT RANGE FOR pH COLOR CHANGE
GREEN BROMOCRESOL 3.8 - 5.4 YELLOW TO BLUE

PURPLE BROMOCRESOL 5.2 - 6.8 YELLOW TO PURPLE

BROMOPHENOL BLUE 3.0 - 4.6 YELLOW TO BLUE

CONGO RED 3.0 - 5.0 BLUE TO RED

METHYL RED 4.8 - 6.0 RED TO YELLOW

METHYL ORANGE 3.2 - 4.4 RED TO YELLOW

NEUTRAL RED 6.8 - 8.0 RED TO AMBER

PHENOL RED 6.6 - 8.0 YELLOW TO RED

PHENOLPHTHALEINE 8.2 - 10.0 TRANSPARENT TO PINK

THYMOL BLUE 1.2 - 2.8 AND 8.0 RED - YELLOW - BLUE
- 9.6 _g_ ARK:jsg070799/1591311.APP
By way of example, the security layer 3 of the present invention may be prepared by combining the resin have acidic or basic functional groups with a suitable pH
sensitive indicator in the form of an emulsion suitable for printing, especially flexographic printing. Suitable components of the emulsion in addition to the resin and the pH sensitive indicator include water, wax emulsions, wetting agents, defoamers and other additives which are well known in the art of ink fomnulations and particularly in flexographic ink formulations.
In another embodiment of the invention, and particularly when it is desirable to detect the presence of an acidic attacking material, a resin having an acidic functional group may be employed. To provide a basic character to the security layer, a basic compound may be added in sufficient quantity to change the pH character of the security layer to one which is basic. The basic additive compound must be sufficient to provide a basic character to the security layer while not adversely affecting the function and properties of the other materials contained within the security layer.
Suitable basic compounds for this purpose include 2-amino-2-methyl-1-propanol and - sodium hydroxide solution.
In a still further embodiment of the invention, a basic character for the security layer can be provided through the use of a substrate which itself has a basic character.
Thus, in this embodiment a resin having acidic functional groups may be used but the overall basic character of the substrate provides a sufficient basic environment to ARK:jsg070799/1591311.APP
enable the detection of an acidic attacking material. Some papers employed for the production of lottery tickets have a basic character and can be used in accordance with the present invention in this manner.
The placement of the security layer, as previously indicated, may also be above the game data layer 4 but below the scratch-off layers 7-11. As specifically shown in Figure 2, a security layer 20 of the type described above is shown positioned above the game data layer 4. The security layer 20 may be used alone or as specifically shown in Figure 2 in combination with a security layer 3 positioned below the game data layer 4.
In a still further embodiment of the invention as shown in Figure 3, a security layer may be positioned above the overprinting layers 11-15. As specifically shown in Figure 3, security layer 21 is shown positioned directly above the overprinting layers 11-15. The security layer 21 may be used alone or in combination with security layers 3 and 20 as discussed above. In the embodiment specifically shown in Figure 3, the - lottery ticket 30 is shown with a security layer 3 and a security layer 21.
As previously indicated, the resin employed in the composition of the present invention which is used for the security layer has either a basic or acidic character which may change when the resin goes from a liquid to a dried condition.
Resins with acidic functional groups are more typical for use in the present invention but a basic ARK:jsg070799/1591311.APP
character can be provided to the security layer through the employment of basic additives as previously indicated.
It is desirable for the resin material to have a solid content within the range of from about 30 to 70 weight percent, and a glass transition temperature (Tg) of from about -20 to 100°C. Preferably, the solids content of the resin is from about 35 to 65 weight percent and the glass transition temperature of the resin is preferably from about 0 to 60°C.
Water based acrylic emulsion systems are preferred for use in the present invention because they are especially adapted for ink jet receptivity and provide good print quality even if no pigment or fillers are used in the formulations. Such pigment and filler free formulations impart good overall resistance to game data leeching from the back of the ticket as a result of delamination or solvent attack.

A composition for use in a security layer in accordance with Figure 1 of the present invention is described below. A water based acrylic emulsion was formed having a solids content of 47% and a pH of 8.0 by combining the materials in the amounts indicated in Table 2.

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Table 2 Lucidene 243 (resin) 88.00 Drew Plus L-475A (defoamer) 0.50 Liquilube 405 (wax emulsion) 4.50 Phenolphthaleine 1.50 30% Sodium Hydroxide in Water 5.50 100.00 Lucidene 243 is an acrylic emulsion composed of styrene-2-ethyl hexyl acrylate and methyl methacrylate with functional groups composed of acrylic and carboxylic acid. The resin has a solids content of 49.0% a pH of 8.25 and a glass transition temperature of 7°C.
The thus produced emulsion has a pH of 13.25 and a solids content of 47.0%.
The emulsion was applied to a lottery ticket through the use of a flexographic printing press. Upon exposure to an acidic attacking material (e.g. acetic acid and/or citric acid), the phenolphthaleine changed color from pink to clear.

The procedure of Example 1 was repeated except that the composition for the security layer contained the materials set forth in Table 3.

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Table 3 Phenol Red Sodium Salt 0.40 Water 18.59 Isopropanol 9.80 Glycol Ether EB 1.00 Aerosol MA-80 (wetting agent) 0.20 Foamaster NDW (defoamer) 0.01 Carboset GA-1105 (resin) 52.50 Carboset GA-1103 (resin) 17.50 100.00 The resin Carboset GA1103 and 1105 are styrene acrylic copolymer emulsions obtained from BF Goodrich Company and having the properties indicated in Table 4.
Table 4 Carboset GA-1105 Carboset GA-1103 Solids: 49.0% 49.5 pH: 2.5 4.0 Tg: 55°C 20°C
The emulsion shown in Table 3 was applied as a security layer onto a lottery ticket to produce a security layer having a pH of 4.75 and a solids content of 35.0%.
When exposed to a basic attacking material (e.g. ammonia solution, 2-butoxy ethanol/
ammonia hydroxy (sold under the brand name Windex) or sodium hydroxide) the security layer underwent a color change from yellow to red.

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The procedure of Example 1 was repeated except that a security layer was provided with a composition as shown in Table 5. The composition exhibited a pH of 3.0 and a solids content of 48%.
Table 5 Component Carboset GA-1103 (resin) 87.50 Citric acid (pH adjustment) 4.00 BYK 024 (defoamer) 0.20 Water 3.80 Blue Bromo Phenol 4.50 100.00 A lottery ticket was prepared having a security layer formed from in the composition shown in Table 5. The lottery ticket was contacted with a basic attacking material (e.g. ammonia solution, 2-butoxy ethanol/ammonia hydroxy (sold under the brand name Windex) or sodium hydroxide). The pH sensitive indicator (blue bromo phenol) changed color from yellow to blue when exposed to the basic attacking material.

Claims (17)

1. A printed document comprising:
a) a non-foil containing substrate;
b) data printed over at least a portion of the substrate;
c) at least one security layer applied above, below or both above and below the data, said at least one security layer comprising a composition which, upon exposure to undesirable contact by an attacking material which can expose the data, undergoes a change of a property which can be visually observed.

2. The printed document of claim 1 in the form of a lottery ticket.

3. The printed document of claim 1 further comprising at least one scratch-off layer covering the data.

4. The printed document of claim 3 further comprising at least one overprint layer above the scratch-off layer.

5. The printed document of claim 1 wherein the composition comprises pH
sensitive indicator and a resin having an acidic or basic functional group.

6. The printed document of claim 5 wherein the resin has an acidic functional group.

7. The printed document of claim 1 wherein the change of property is a change of color.

8. The printed document of claim 5 wherein the pH sensitive indicator changes color when exposed to said attacking material.

9. The printed document of claim 8 wherein the resin has an acidic functional group and the pH sensitive indicator changes color when the attacking material is basic.

10. The printed document of claim 6 wherein the resin is a polymer having acrylic acid groups.

11. The printed document of claim 6 wherein the composition further comprises a basic substance which provides the composition with a basic pH, said pH
sensitive indicator changing color when the attacking material is acidic.

12. The printed document of claim 6 wherein the substrate is basic, said pH
indicator changing color when the attacking material is acidic.

13. A composition for use on a printed document to detect exposure to an attacking material comprising:
a) a resin having an acidic or basic functional group; and b) a pH sensitive indicator.

14. The composition of claim 12 wherein the pH sensitive indicator changes color.

15. The composition of claim 13 wherein the resin is a polymer having acrylic acid groups.

16. A method of detecting tampering of a printed document comprising applying to said printed document a composition comprising a resin having an acidic or basic functional group and a pH sensitive indicator wherein when said document is attacked by an acidic or basic material the pH sensitive indicator changes color indicating the presence of said attacking material.

17. The method of claim 16 wherein the printed document is in the form of a lottery ticket.