DETAILED DESCRIPTION

[0033] Pull-aparts can be used for a variety of purposes where printed information is intended to be concealed from view until revealed by separating layers of a laminate. These purposes include game pieces, promotional articles, and report forms. The pull-apart game pieces themselves can be used for a variety of purposes including low-stakes wagering, fundraising, and advertising. Other purposes include use as an alternative to scratch-off latex games, which can be messy. Direct thermal printing of such game pieces at point of sale or distribution to determine winnings is expected to provide heightened security over game pieces with preprinted results while providing a construction that still allows for the deferred revelation of the results by removing or otherwise retracting a tab.

[0034] The pull-apart promotional articles provide for distributing coupons or product offerings in an interactive format. The pull-apart report forms provide for the controlled distribution of confidential, proprietary, classified, restricted, or personal information, particularly to targeted individuals. For example, information such as test scores, lab results, banking codes, shipping data, and prize winning announcements can be printed on demand while concealed from view until the pull-aparts are irreversibly opened.

[0035] A strip of exemplary pull-aparts in the form of game pieces 10 is depicted in FIGS. 1-3. As shown particularly in FIG. 3, the pull-apart game pieces 10 are an assembly of two substrates, base substrate 12 and cover substrate 22. The base substrate 12 is an at least partially transparent (e.g., translucent) paper or film having a front surface 14 supporting a thermosensitive imaging layer 18. Thermal images 20 (e.g., game results) formed in the thermosensitive imaging layer 18 on the front surface 14 of the base substrate 12 are visible through a back surface 16 of the base substrate 12.

[0036] The base substrate 12 and thermosensitive imaging layer 18 are preferably acquired together as a direct thermal printable paper or film. One example is an 81 micron polypropylene film, product number C-100 from Kanzaki Specialty Papers of Ware, Mass., coated with an ultra-high sensitivity thermosensitive coating for reacting with heat to form black images. Direct thermal papers are available from Appleton Papers Inc. of Appleton, Wis.

[0037] The cover substrate 22, which can also be made of paper or film, has a front surface 24 that is partially bonded to the back surface 16 of the base substrate 12 with a patterned permanent adhesive 28. One or more layers of printing ink 30 are applied to a back surface 26 of the cover substrate 22, which are visible in FIG. 2 as printed images on a back surface 36 of the pull-apart game pieces 10. Either the cover substrate 22 or the layers of printing ink 30, and preferably both, are opaque to obscure any view of the thermal images 20 through the back surface 36 of the pull-apart game pieces 10.

[0038] Also shown in FIG. 2 as well as in FIG. 3 are patterns of perforations 32, which partially surround gaps in the patterned permanent adhesive 28. The patterns of perforations 32 are cut through both the layers of printing ink 30 and the cover substrate 22 to form retractable tabs 40 that can be pulled away or otherwise separated from the base substrate 12 forming window frames 42 within which the thermal images 20 can be viewed through the base substrate 12.

[0039] A temporary adhesive 38 such as a clean release or fugitive adhesive can be applied between the retractable tabs 40 and the base substrate 12 to hold the tabs 40 in place and to prevent the formation of air pockets within the pull-aparts 10. Such air pockets can cause undesirable wrinkling or delaminating, particularly during manufacture. The temporary adhesive 38 forms a weak bond that prevents the formation of air pockets but is easily broken to allow retraction of the tabs 40. Hot-melt or water-based adhesives can be used for this purpose. However, a combination of a water-based adhesive applied over a layer of release on the back surface of the base substrate 12 is preferred to provide reliable release properties without leaving sticky residue on either the tabs 40 or the base substrate 12.

[0040] One of the retractable tabs 40 is shown in a retracted position in FIG. 2, revealing thermal images 20 in the form of two different star burst patterns within one of the window frames 42 formed in a remaining bonded portion of the cover substrate 22. The window frames 42 limit the viewing area of the thermosensitive imaging layer 18 to the thermal images 20 immediately beneath the retractable tabs 40 that are pulled apart from the window frames 42.

[0041] To enhance the visibility of the thermal images 20 through the windows 42 while obscuring visibility of the same thermal images 20 from a front surface 34 of the pull-apart game pieces 10 (see FIG. 1), an opaque coating 46 (see FIG. 3) is applied over the thermosensitive imaging layer 18 on the front surface 14 of the base substrate 12. The opaque coating 46 is preferably a layer of printing ink in a color (e.g., white) that contrasts with the color (e.g., black) of the thermal images 20 to enhance visibility of the thermal images 20 through the back surface 16 of the translucent base substrate 12. However, the opaque coating 46 impairs transmissions of light to at least partially obscure view of the same thermal images 20 through the front surface 34 of the pull-apart game pieces 10. One such ink is an opaque UV white sold as product number UFA 90100 by Akzo Nobel of Plymouth, Minn. Other colors are also available.

[0042] One or more additional printing layers 48 can be applied over the top of the opaque coating 46 to form printed images on the front surface 34 of pull-apart game pieces 10 or to further obscure the front-side view of the thermal images 20. The printed layers 48 can contain information for playing or promoting the game or patterns, such as confusion patterns for additionally obscuring the thermal images 20. However, the opaque coating 46 and printing layers 48 are sufficiently thermally transmissive (e.g., sufficiently thin) to enable the thermal images 20 to be printed by a conventional direct thermal printer through the front surface 34 of the pull-apart game pieces 10. The required thermal transmissivity requires heat conduction with a minimum of dispersion, which can be accomplished by material thinness or material compositions that preferentially conduct heat in the thickness dimension over other directions that would tend to blur the thermal images 20.

[0043] As shown in FIGS. 1 and 2, the pull-apart game pieces 10 are separated from one another along a continuous strip or web 50 by lines of perforation 52. The strip 50 of pull-apart game pieces 10 is preferably loaded into a direct thermal printer in a continuous form such as a roll or fan-folded stack. The direct thermal printing through the front surface 34 of the pull-apart game pieces 10 should be mirror reversed to permit the desired image to be viewed from the back surface 36 of the pull-apart game pieces 10.

[0044] Following the direct thermal printing of the thermal images 20 (e.g., game results), the individual pull-apart game pieces 10 are separated in groups of one or more along the lines of perforation 52. Alternatively, the pull-apart game pieces 10 can be pre-cut or otherwise separated in sheet form prior to being loaded into the direct thermal printer. The printer can also be assembled with a cutting mechanism as an alternative to use of perforations.

[0045] The first two drawing figures illustrate three retractable tabs 40 per game piece 10. However, the number of retractable tabs 40 per game piece 10 can vary considerably from one to six or more. The pattern of perforations 32 preferably leaves some portion of each of the retractable tabs 40 connected to the cover substrate 22 after retraction to reduce instances of scrap. The remaining portions of the retractable tabs 40 preferably remain bonded to the base substrate 12. Alternatively, the tabs 40 could be cut out along continuous rather than perforated lines and held in place with a clean release or fugitive adhesive. In addition, the cover substrate 22 could be formed as one or more retractable tabs 40 without the surrounding window frames 42, and a clean release or fugitive adhesive could be applied to hold them in place on the base substrate 12.

[0046] Another exemplary pull-apart game piece 60 shown in FIG. 4 looks and functions similar to the pull-apart game pieces 10 but has a different cross-sectional configuration. The assembly requires three substrates: a base substrate 62, a cover substrate 72, and a thermally transmissive substrate 82. Like the preceding embodiment, the base substrate 62 is an at least partially transparent (e.g., translucent) paper or film.

[0047] Also similar to the preceding embodiment, a front surface 74 of the cover substrate 72 is bonded by a patterned adhesive layer 68 to a back surface 66 of the base substrate 62. One or more layers of printing ink 80 cover the back surface 76 of the cover substrate 72. Preferably, both the cover substrate 72 and the printed ink layers 80 are opaque. A pattern of perforations 78 formed through the printed layers 80 and the cover substrate 72 form retractable tabs 96 similar to the preceding embodiment.

[0048] A back surface 86 of the thermally transmissive substrate 82 supports a thermosensitive imaging layer 88 within which thermal images 90 (e.g., game results) are formed. A permanent adhesive layer 92 bonds the thermally transmissive substrate 82 to a front surface 64 of the base substrate 62. Preferably, the thermally transmissive substrate 82 is opaque in a color that contrasts with a color of the thermal images 90. One or more layers of printing ink 94 cover the front surface 84 of the thermally transmissive substrate 82 to further obscure the thermal images 90. Among the layers of printing ink 94 can be a confusion pattern as well as information associated with the play or promotion of the pull-apart game piece 60.

[0049] The thermally transmissive substrate 82 can be a paper or film, but must be sufficiently thermally transmissive (e.g., having a thickness around ten microns or less) to support the direct thermal printing of the thermal images 90 in the thermosensitive layer 88 through its front surface 84. The direct thermal printing is preferably accomplished by conventional direct thermal printers that are widely available with standardized units of heat output power. Examples of direct thermal printable films laminated to underlying substrates are described in U.S. Pat. No. 6,124,236, entitled Direct Thermal Printable Film and Laminate, to one of the joint inventors herein, which is hereby incorporated by reference. Thin paper, such as paper referred to as “Bible paper”, can also be used as the thermally transmissive substrate 82. A thin direct thermal paper is available from Appleton Papers Inc. of Appleton, Wis., under the trade name OPTIMA POS Plus thermal paper and having a target thickness of 0.002 inches or 50 microns. Any thermal insulating layer between the paper substrate and the thermosensitive imaging layer is preferably removed or replaced by a more thermally conductive layer.

[0050] The retractable tabs 96 can be pulled apart from remaining portions of the cover substrate 72 along the lines of perforation 78 to reveal the thermal images 90 through the translucent base substrate 62. The thermally transmissive substrate 82 through which the images 90 are printed preferably provides both contrast for enhancing the view of the images 90 through the base substrate 62 and opacity for obscuring the view of the images 90 through the thermally transmissive substrate 82.

[0051] Instead of supporting the thermosensitive imaging layer 88 on the back surface 86 of the thermally transmissive substrate 82, the thermosensitive imaging layer 88 could be supported on the front surface 64 of the base substrate 62 similar to the preceding embodiment. However, transmissions of heat from direct thermal printing would be required to conduct through both the thermally transmissive substrate 82 and the adhesive layer 92 that permanently bonds the thermally transmissive substrate 82 to the base substrate 62.

[0052] Another pull-apart game piece 100, which is depicted in FIGS. 5 and 6 also includes a thermally transmissive substrate 102 having on its back surface 106 a thermosensitive layer 108 that is thermally imageable through its front surface 104 similar to the thermally transmissive substrate 82 of the immediately preceding embodiment. However, instead of mounting the thermally transmissive substrate 102 on a transparent base substrate, the thermally transmissive substrate 102 is mounted directly onto a cover substrate 112. A patterned permanent adhesive 110 attaches a perimeter of the thermally transmissive substrate 102 to the cover substrate 112.

[0053] Along the perimeter pattern of permanent adhesive 110, die-cut lines of perforation 114 are formed through the cover substrate 112 to form a retractable tab 116. Through cuts 115 form an ear of the retractable tab 116 for gripping and retracting the tab 116. A clean release or fugitive adhesive 118 temporarily attaches the retractable tab 116 to the back surface 106 of the thermally transmissive substrate 102. The permanent adhesive 110 permanently bonds a remaining portion 122 of the cover substrate 112 to the thermally transmissive substrate 102. The remaining portion 122 of the cover substrate 112 has a closed shape that frames a window 124 that is opened by retracting the tab 116. The closed shape of the remaining portion 122 provides a frame for retaining a planar shape for the thermally transmissive substrate 102 as well as an intrinsic support for retracting the tab 116. The support functions afforded by the closed shape of the remaining portion 122 of the cover substrate 112 enables the thermally transmissive substrate 102 to be optimized for thermal conductivity. For example, the thermally transmissive substrate 102 can be made from a film that is less than ten microns thick.

[0054] The thermally transmissive substrate 102 can (as far as its thickness permits) be made opaque. However, an opaque coating 126 can also be applied to the thermally transmissive substrate 102 for obscuring a view of thermal images 128 through the front surface 104 of the thermally transmissive substrate 102 while providing contrast for viewing the thermal images 128 through the window 124 formed in the cover substrate 112. Patterns 130 can be printed on the front surface 104 of the thermally transmissive substrate 102 or on either surface of the cover substrate 112 to further obscure the view of the thermal images 128. Retraction of the tab 116 opens the window 124 through the cover substrate 112, revealing the thermal images 128 printed in the thermosensitive imaging layer 108.

[0055] Alternatively, the cover substrate 112 could be made thermally transmissive, permitting the substrate 102 to be made more substantial. The thermal images 128 would then be printed through the cover substrate 112 and the temporary adhesive 118. The die cuts 114 could then be made through the more substantial substrate 102 to reveal the thermal images on the back surface of a retracted tab.

[0056] An exemplary pull-apart in the form of a promotional article 140 is depicted in FIGS. 7 and 8. The promotional article 140 is built upon two substrates—an at least partially transparent base substrate 142 and a cover substrate 148. A thermosensitive imaging layer 154 directly overlies a front surface 144 of the base substrate 142. An opaque coating 156 and a printed pattern 158 cover the thermosensitive imaging layer 154. Die cuts 160 through the printed pattern 158, the opaque coating 156, the thermosensitive imaging layer 154, and the base substrate 142 define a tab 162 that is partially or completely removable from a surrounding portion 164 of the base substrate 142. The die cuts can be made in a continuous or discontinuous pattern (e.g., perforations) depending upon the degree or manner in which the tab 162 is required to be attached to the remainder of the pull-apart 140.

[0057] A permanent adhesive layer 166 permanently bonds the surrounding portion 164 of a back surface 146 of the base substrate 142 to a front surface 150 of the cover substrate 148. A temporary adhesive layer 168 temporarily bonds the tab 142 to the cover substrate. Although shown as a single layer, the temporary adhesive 168 can be composed of multiple layers, such as a combination of adhesive and release layers. In addition, in place of separate permanent and temporary adhesive materials, the same adhesive material could be used to cover the entire back surface 146 of the base substrate 142 together with a layer of release applied only in the region of the tab 162 to provide the desired temporary bond.

[0058] Graphic layers 170 and 172 are printed onto the front surface 150 and a back surface 152 of the cover substrate 150. At least the graphic layer 170 is pre-printed during the assembly of the pull-apart promotional article 140 as a form of a thermally printable medium. Prior to distribution or use, thermal images 174 are thermally printed in the thermosensitive imaging layer 154 through the overlying printed pattern 158 and the opaque coating 156. The thermal images 174 are concealed by the printed pattern 158 (which can be printed as a confusion pattern) and the opaque coating 156 from the front side 144 of the base substrate and by the cover substrate 148 and its graphic layers 170 and 172 from the back side 146 of the base substrate 142.

[0059] Retraction of the tab 162, including its complete or partial removal, exposes the thermal images 174 through the back surface 145 of the at least partially transparent base substrate 142. The opaque layer 156 is preferably printed with an ink of a color that contrasts with a color of the thermal images 174. In addition, the retraction of the tab 162 reveals the pre-printed graphics 170 on the front surface 150 of the cover substrate 148 through a window 176 bordering the surrounding portion 164 of the base substrate 142.

[0060] Adhesive materials or films that favor the conduction of heat along one orthogonal axis (i.e., an axis corresponding to a thickness dimension) over the remaining two orthogonal axes could be used (for either or both of the adhesive layer 92 and thermally transmissive substrate 82) to maintain concentrated transmissions of heat through larger distances. Such materials or arrangements of materials that exhibit uniaxial anisotropic electrically conductive properties having metal particle or fiber alignments are also likely candidates for supporting similar anisotropic thermally conductive properties. Thermagon, Inc. of Cleveland, Ohio, produces a range of thermally conductive dielectric polymers, including T-gon 300 and 400 series paste adhesives, that could be printed (e.g., screen printed) in a dot matrix form to favor heat transfers between adjacent layers with a minimum of lateral thermal diffusion.

[0061] The thermal coupling materials or material arrangements exhibiting uniaxial anisotropic thermal conductivity have widespread relevance to imaging thermosensitive materials through overlying layers and larger distances from thermal print heads. Such materials in the form of adhesives can provide for bonding protective layers (e.g., paper or film substrates) over otherwise supported thermosensitive imaging layers. In other forms, such as coatings, the materials themselves can provide protection and other overlying functions. For example, in accordance with the illustrated embodiments, the thermal coupling layer is preferably opaque to obscure the image formed in the thermosensitive layer until the pull-apart is retracted.

[0062] Although the pull-apart game pieces 10, 60, and 100 and promotional article 140 and their various substrates are referenced with respect to front and back surfaces, the labels of “front” and “back” are used for convenience of reference only and can be altogether exchanged with one another without any structural implications.

[0063] The new pull-aparts 10, 60, 100, and 140 can be manufactured along in-line presses for performing sequential operations involving printing, coating, die cutting, laminating, and rolling or stacking. The printing operations for repeating patterns are preferably performed using flexographic printing processes. Digital printing is preferred for printing security codes or other variable information.