EP0668092A1

EP0668092A1 - Lottery ticket paper

Info

Publication number: EP0668092A1
Application number: EP95300700A
Authority: EP
Inventors: Mark Victor Watson
Original assignee: Wiggins Teape Group Ltd
Current assignee: Arjo Wiggins Fine Papers Ltd
Priority date: 1994-02-19
Filing date: 1995-02-03
Publication date: 1995-08-23
Also published as: CA2141982A1; GB9403237D0; JPH07242086A

Abstract

A lottery ticket, for example of the "instant" scratch-off kind, comprises a non-opaque base paper and a coating layer or layers positioned between the base paper and win-or-lose indicia carried by the ticket. The coating is not self-supporting, so that it is not itself susceptible to fraudulent delamination, and is opaque with respect to transmitted light. Thus even if the base paper is delaminated, the win-or-lose indicia are still not discernible on viewing the ticket against a high intensity light source, since the opaque coating is still between the indicia and the light source. The desired opacity of the coating is achieved by the use of opaque pigments such as carbon black or aluminium powder or flake. The opaque coating can carry a light-coloured topcoat for enhanced printability, or a lustrous topcoat giving an attractive decorative effect.

Description

This invention relates to lottery tickets and to paper used in the production of such tickets. The lottery tickets are typically of the so-called "instant" type where the purchaser removes a covering layer, typically a scratch-off layer to reveal underlying indicia which determine whether or not the ticket is a winning ticket.
An essential requirement of such a lottery ticket is that it must be secure against fraud. Thus it must not be possible for anybody to determine whether a particular ticket is a winning or losing ticket without removing the covering layer and thereby rendering the ticket non-reusable. Equally, the ticket must be secure against counterfeiting, i.e. unauthorised production of complete tickets, and against tampering, for example transferring winning indicia from a used ticket to another ticket which can be suitably overprinted and presented as unused so as to win a second time.
Hitherto, lottery tickets based on an aluminium foil/paper laminate have achieved widespread commercial acceptance. The aluminium foil provides complete opacity with respect to transmitted light, which is necessary to prevent the underlying win-or-lose indicia being visible when the ticket is held up against a strong light. It should be appreciated in this regard that many papers or other products which appear to be opaque in everyday use are in fact opaque only with respect to reflected light and not transmitted light. This is especially true with a powerful light source such as a xenon lamp or a high intensity tungsten halogen spotlight.
However, the use of an aluminium foil/paper laminate has a number of disadvantages. Firstly, the foil is self-supporting and therefore potentially de-laminable from the paper. Tickets using such foil are therefore vulnerable to tampering. Secondly, aluminium foils and base papers are fairly readily available, so that the risk of counterfeiting is relatively high. Whilst this risk can be reduced by the use of security chemicals or other security elements in the paper, it cannot be eliminated. Thirdly, aluminium foil is fairly readily damaged by accidental bending or folding, either before or during printing of the tickets, and so wastage tends to be high. Fourthly, the use of aluminium foil means that waste produced during production of the tickets or after their use is not readily recyclable, since it is not re-pulpable.
European Patent Application No. 428489A proposes to avoid these drawbacks by the use of a ticket base paper in which the desired opacity with respect to transmitted light is achieved by a loading within the base paper of a dark pigment such as carbon black. Since such a dark paper is not adequately printable, the paper is coated on both of its surfaces with a printable light-coloured pigment/filler/binder composition of generally conventional kind.
Such a lottery ticket paper avoids many of the drawbacks of aluminium foil/paper laminates as outlined above, but it is potentially susceptible to tampering by delamination within the thickness of the paper. Since the light-coloured coating composition is not itself opaque with respect to transmitted light, and since the fibre layer remaining after delamination is too thin to provide adequate opacity, the win-or-lose indicia can be revealed by viewing the delaminated ticket against a high intensity light source, and the winning tickets can be thereby identified. These can then be reassembled and the prizes claimed. Similarly, a used winning ticket is susceptible to careful delamination and transfer of the winning indicia to a complementary portion of a delaminated losing ticket.
Lottery tickets have also been proposed in which the ticket comprises a laminate of at least two self-supporting plies which are peeled apart to reveal the win-or-lose indicia, see for example U.S. Patent No. 4120445. The win-or-lose indicia may be present on one of the plies, or may be present on an insert included in a pouch formed by two of the plies. A drawback of such tickets is that an additional manufacturing step is required in their production, i.e. it is necessary not only to produce coated substrates to which win-or-lose indicia can be applied, but also to carry out a manufacturing and conversion operation to produce the desired laminate or pouch construction.
It is an object of the invention to provide lottery tickets in which the drawbacks of the ticket constructions described above are overcome or are made less serious.
According to the invention, there is provided a multi-layer lottery ticket carrying win-or-lose indicia and comprising:

a) a paper substrate layer constituting the only self-supporting layer of the ticket and not being opaque with respect to transmitted light;
b) a coating layer or layers positioned between said substrate layer and the win-or-lose indicia and being substantially opaque with respect to transmitted light so as to prevent the win-or-lose indicia becoming visible on viewing the ticket against a high intensity light source; and
c) a removable covering layer over the win-or-lose indicia, said covering layer being opaque with respect to reflected light so as to prevent the win-or-lose indicia being visible until the covering layer is removed.

The opacity-imparting coating layer or layers can be based, for example, on opacifying pigments, such as carbon black, graphite and/or an opaque lustrous pigment such as aluminium powder or flake, together with a suitable binder or binder blend. The binder is typically a latex, for example a styrene-butadiene latex, optionally in a blend with another type of latex, such as a polyvinyl acetate emulsion. Strongly light-absorbing dyes, e.g. black or dark blue dyes, can be used to enhance the opacity of the coating. Whilst in principle these could provide all the desired opacity, it is generally found in practice that such dyes cannot provide the desired degree of opacity on their own, i.e. without the use of opacifying pigments as well.
The opacity-imparting coating layer or layers can be applied by coating techniques conventional in the paper industry, for example air-knife coating, metering roll coating, Meyer bar coating, blade coating or rod blade coating. Alternatively, this coating layer or layers can be applied, if suitably formulated, by means of a printing press.
The paper substrate can be a conventional white or coloured paper. It should be of sufficient stiffness to be readily handleable, and typically has a grammage of the order of 200 to 220 g m⁻².
In the case of a coating containing carbon black or another dark pigment or a dark-coloured dye, a lighter-coloured pigment/binder topcoat is normally required to make the paper suitable for receiving a print of sufficient legibility. Inorganic pigments such as calcium carbonate, kaolin, or titanium dioxide, or organic paper coating pigments, may be used in the topcoat. The binder is typically a latex, for example a styrene-butadiene latex. In principle however, a topcoat is not essential, since a black or dark coating could be printed with white or silver or other contrasting inks. In the case of an opaque coating which is lustrous, for example an aluminium powder or flake coating, a topcoat is not necessary for subsequent printing legibility, since the coating has a relatively light shiny appearance despite its opacity (this lustrous coat can if desired be coloured using conventional dyes, toners or other colourants). A topcoat lacquer, for example a clear topcoat,can of course be applied for other reasons, for example to improve the cohesion of the pigment coating and thereby reduce dusting or pick-off during printing.
Although aluminium flake can provide good opacity, a high coatweight, say at least 25 g m⁻², is required to give absolutely no light transmission, where this is necessary. This is expensive, and also difficult to apply in a single coating operation. It is therefore preferable to employ a dark undercoat when using an aluminium flake coating. Such an undercoat can contain a dark dye or a dark pigment such as carbon black or graphite. The use of such an undercoat can reduce the aluminium flake coatweight required to a more manageable value, say around 15 g m⁻². An alternative possibility is to use a mixture of aluminum powder or flake and a dark pigment in a single coating layer.
The topcoat can if desired be given a distinctive decorative appearance, for example by the use of iridescent, pearlescent or other lustrous pigments which are not actually metallic in nature, and, in contrast to metallic pigments, do not impart opacity with respect to transmitted light. Such mica-based pigments are generally composed of thin flakes of mica coated with metal oxides such as titanium dioxide or iron oxide. A variety of hues and coloured effects can be obtained, for example a pearl lustre in silver, red, yellow, blue, green or other shades, or a metallic lustre in for example silver, gold, burnished gold, copper or bronze. These pigments are commercially available, for example from the firm E. Merck of Darmstadt in Germany or their agents under the trademarks "Iriodin" in Europe and "Afflair" in USA and Canada.
The present lottery ticket paper can be printed up into lottery tickets in conventional manner. Typically this involves applying the win-or-lose indicia and any necessary identifying information, for example a number or bar code, in a first printing operation, and then overprinting a covering layer which is opaque with respect to reflected light so as to prevent the win-or-lose indicia being visible. The covering layer can embody decorative and informational material, for example the name of the lottery, details of the promoter, or advertising, or such decorative and informational material can be applied in a further printing operation. The win-or-lose indicia are generally applied using a U.V. curable ink, for example by means of an ink-jet printer. This gives a very low-profile print which cannot be detected tactilely through the overprint. The covering layer or layers, which can be of the scratch-off kind, can be applied, for example, by rotary screen printing or flexography. Suitable formulations for such scratch-off coatings are discussed in "The Printing Ink Manual" published by Van Nostrand Reinhold (International) Co. Ltd. in association with the Society of British Printing Ink Manufacturers (Fourth Edition 1988 pages 509 and 510). Typically they contain aluminium powder to give covering power (opacity), so-called "pliable" resins to give scratch-off characteristics, and, optionally organic pigments to give coloured or decorative effects.
The reverse surface of the paper substrate, i.e. the surface opposite to that carrying the opacity-imparting coating, can be left uncoated, since in contrast to the loaded paper disclosed in European Patent Application No. 428489A, it is easily printable by conventional techniques.
The present lottery ticket paper has the advantage that although in principle it could be delaminated within the thickness of the paper, the win-or-lose indicia on the ticket could still not be seen on exposing the ticket to intense light. This is because in contrast to the proposal of European Patent Application No. 428489A, it is the coating rather than the base paper which provides the opacity. Thus there is always an opaque layer between the indicia and the reduced thickness portion of base paper remaining after delamination. The coating, being particulate in nature rather than a self-supporting ply, lacks the integrity to exist on its own without any fibrous support layer, and attempts at tampering with the coating will be readily apparent in any case.
Since the present paper utilises no foil layer, waste can be re-pulped and recyclability is therefore less of a problem than with the foil/paper laminates generally used hitherto.
The paper substrate and/or any of the coatings on it can incorporate additional security and/or decorative features, for example by the inclusion of dyes, colour-generating or -changing chemicals, coloured and/or "invisible" planchettes, sparkling inclusions, instant verification chemicals, sensitising chemicals for detecting attempts at fraudulent alteration, metallic or iridescent pigments and suchlike. All of these are known in themselves and so need no further description. The paper substrate may additionally include Silurian fibres or security threads, filaments or strips, as used conventionally in security papers.
The invention will now be illustrated by the following Examples, in which all parts and percentages are by weight unless otherwise stated.

Example 1

Two aqueous coating compositions were made up as follows:
Composition A was coated on to 200 g m⁻² stiff white non-opaque coating base paper by means of a Meyer bar coater. The dry coatweight applied was c. 8 g m⁻². After drying, Composition B was applied over the top of the Composition A coating, also by means of a Meyer bar coater. The dry coatweight was c. 12 g m⁻², giving a total grammage for the coated paper of c. 220 g m⁻². The thus-coated paper was then calendered to a Bendsten smoothness of c. 50 to 100 ml.min⁻¹.
The coated surface of the paper was of white appearance with minimal show-through of the underlying carbon black coating. No light showed through when the coated paper was held up against a 12 volt, 20 watt, high intensity tungsten halogen spotlight giving a 20 cm diameter beam of intensity 3350 lux at a distance of 1 metre. The same test was carried out after the paper had been printed on its coated surface (to simulate win-or-lose indicia), and as would be expected, it was not possible to discern the printing from the reverse side of the paper.

Example 2

An aqueous coating composition was made up as follows:
This composition was coated on to the same type of paper as in Example 1, also by means of a Meyer bar coater. The dry coatweight was c. 15 g m⁻². The thus-coated paper was then calendered to a Bendsten smoothness of c. 50 to 100 ml min⁻¹. The product had a metallic silvery appearance, and when held up to the same light as described in Example 1, there was virtually no light transmittance. After printing on the coated surface and repeating the test, the printed characters could not be discerned.
Subsequently a portion of the unprinted paper was further coated with a clear lacquer by means of a gravure technique. This was found to reduce pick-off and dusting of the coating on printing, compared with the unlacquered product.

Example 3

An aqueous carbon black opacifying coating composition was made up at 37% solids content using 30% solids content carbon black dispersion ("Forthsperse Black PC1") supplied by Croda Colours of Brighouse, West Yorkshire, England) and 50% solids content styrene-butadiene latex ("Dow DL 950"). The amounts of carbon black and latex were chosen so as to give equal weights of carbon black and latex on a dry basis. The coating composition was then applied to 195 g m⁻² white woodfree uncoated base paper using a pilot-scale air knife coater. The bone dry coatweight applied was c. 10 g m⁻².
A 50% solids content aluminium flake/styrene butadiene latex topcoat composition containing aluminium flake ("Aquavex 301-2075") and latex ("Dow DL950") in 30:70 weight ratio on a dry basis was then applied to a portion of the dried carbon black-coated paper. The same air knife coating technique was used as before, but the dry coatweight applied was c. 5 g m⁻².
A white 60% solids content topcoat composition was then applied to another portion of the dried carbon black-coated paper. This white topcoat contained, on a dry basis, 70% anatase titanium dioxide ("Tioxide AHR" supplied by Tioxide Europe Ltd. of Billingham, England), 15% kaolin ("SPS"supplied by ECC Ltd. of St. Austell, England), and 15% styrene-butadiene latex ("Dow DL 950"). The same air knife coating was used as described previously, but the dry coatweight applied was c. 25 g m⁻².
No light showed through when each of the resulting papers were held up against a high intensity spotlamp as described in Example 1. Measurements using an Elrepho spectrophotometer confirmed that the papers were wholly opaque with respect to transmitted light.

Example 4

This illustrates the use of a range of lustrous pigments for giving iridescent pearlescent, or metallic decorative effects.
Sample sheets of a 150 g m⁻² white coated woodfree base paper were coated with a carbon black composition as described in Example 3 by means of a laboratory Meyer bar coater to give a dry coatweight of c. 10 g m⁻². After drying, a range of different topcoats were applied to respective sample sheets. These contained, on a dry basis, 40% by weight of iridescent pigment and 60% by weight of vinyl acetate/vinyl chloride/ethylene terpolymer latex ("Vinamul 3452" supplied by Vinyl Products Ltd. of Carshalton England), and were applied at 30% solids contant again using the laboratory Meyer bar coater. The dry coatweight applied was c. 5 gm⁻² in each case.
The lustrous pigments used were all supplied under the trade mark "Iriodin" by E. Merck and were as follows:
The coated surfaces of the paper produced were of iridescent, pearlescent or metallic appearance with minimal show through of the underlying carbon black coating. The lustrous pigment was well bound to the precoat surface, and no dusting or picking was evident on printing.
No light showed through when the papers were held up against a tungsten-halogen spotlight as described previously, and the printed characters could not be discerned.

Claims

A multi-layer lottery ticket carrying win-or-lose indicia and comprising:
a) a paper substrate layer constituting the only self-supporting layer of the ticket and not being opaque with respect to transmitted light;

b) a coating layer or layers positioned between said substrate layer and the win-or-lose indicia and being substantially opaque with respect to transmitted light so as to prevent the win-or-lose indicia becoming visible on viewing the ticket against a high intensity light source; and

c) a removable covering layer over the win-or-lose indicia, said covering layer being opaque with respect to reflected light so as to prevent the win-or-lose indicia being visible until the covering layer is removed.
A multi-layer lottery ticket as claimed in claim 1 wherein at least two coating layers are positioned between the paper substrate and the win-or-lose indicia, and said layers comprise a dark-coloured undercoat contributing opacity to transmitted light and a lighter topcoat affording good printability with respect to dark ink.
A multi-layer lottery ticket as claimed in claim 2 wherein the dark-coloured undercoat comprises carbon black.
A multi-layer ticket as claimed in claim 3, wherein the lighter topcoat comprises a white or near-white pigment such as calcium carbonate, kaolin and/or a solid or hollow organic paper coating pigment.
A multi-layer ticket as claimed in claim 3, wherein the lighter topcoat comprises a lustrous pigment.
A multi-layer ticket as claimed in claim 5, wherein the lustrous pigment is metallic, for example aluminium powder or flake.
A multi-layer ticket as claimed in claim 5, wherein the lustrous pigment is mica-based.
A multi-layer ticket as claimed in claim 1 wherein the coating layer or layers contributing opacity to transmitted light is or are dark in colour and no lighter topcoat is provided.
A multi-layer ticket as claimed in claim 8 wherein the coating layer or layers comprise carbon black optionally mixed with aluminium powder or flake.
A multi-layer ticket as claimed in claim 1, wherein the coating layer or layers contributing opacity to transmitted light comprises/an opaque lustrous pigment such as aluminium powder or flake.
A multi-layer ticket as claimed in any preceding claim wherein said coating layer or layers contributing opacity to transmitted light carry a protective lacquer topcoat.