This technical disclosure relates to processing personalized plastic identification documents such as personalized plastic cards and plastic pages of passports, and increasing the durability of printing on the personalized plastic identification documents.
Identification documents such as identification cards, credit and debit cards, driver's licenses, and the like, and passports, are personalized with information concerning the intended holder of the identification document and then issued to the intended holder. The durability of printing applied to the identification documents is important in order to extend the life of the identification documents.
Personalized identification document processing systems and methods are described that produce personalized plastic identification documents with highly durable printing while minimizing print ribbon waste and maintaining document processing speeds and system throughput.
In an embodiment, a personalized identification document processing system described herein includes a print station that includes a thermal print head and a print ribbon that is engageable by the thermal print head to thermally transfer material from the print ribbon to personalize the plastic identification document. The print ribbon includes thermally transferrable radiation curable protective topcoat material that is dry to the touch or substantially dry to the touch. The topcoat material is applied to the plastic identification document in a printing process, with the topcoat material applied over at least a portion of color material previously print on the document. The topcoat material is then cured and once cured enhances the durability of the printed color material.
In another embodiment, a first print station is provided that prints thermally transferrable color material from a print ribbon, and a second print station is provided that prints thermally transferrable radiation curable protective topcoat material from a second print ribbon.
Radiation curing of a coating increases the coating toughness. If a topcoat material is fully cured before transfer to the identification document from the print ribbon, the topcoat material does not break cleanly around the edges of the identification document, causing undesired extra material to transfer along the identification document edges. One way of preventing transfer of such extra material is to reduce the thickness of the cured topcoat material, making it less tough. However, the reduced thickness also reduces the overall durability of the printing underlying the topcoat material. To overcome this deficiency, the topcoat material described herein is first transferred to the identification document before being radiation cured. The uncured topcoat material being less tough, transfers to the identification document cleanly, even at a desired higher thickness, without transferring undesired extra material. The transferred topcoat material on the identification document is then radiation cured to enhance its toughness and durability. This approach results in clean transfer of the topcoat material while maintaining the desired durability of the final printed identification document.
In one embodiment, a personalized identification document processing system includes a document input that is configured to input a plastic identification document to be processed onto a document transport path to create a personalized plastic identification document, and a print station along the document transport path. The print station includes a thermal print head and a print ribbon that is engageable by the thermal print head to thermally transfer material from the print ribbon to personalize the plastic identification document. The print ribbon includes thermally transferrable radiation curable protective topcoat material that is dry to the touch or substantially dry to the touch. A radiation curing station is disposed along the document transport path and that is configured to apply radiation to thermally transferrable radiation curable protective topcoat material applied to the plastic identification document from the print ribbon to cure the thermally transferrable radiation curable protective topcoat material on the plastic identification document. The system further includes a document output along the document transport path that is configured to receive the plastic identification document, and a document transport mechanism that is configured to transport the plastic identification document along the document transport path.
In another embodiment, a method of processing a plastic identification document in a personalized identification document processing system includes inputting the plastic identification document to be processed onto a document transport path, and transporting the plastic identification document into a print station located along the document transport path. The print station includes a thermal print head and a print ribbon that is engageable by the thermal print head to thermally transfer material from the print ribbon to personalize the plastic identification document, with the print ribbon including thermally transferrable radiation curable protective topcoat material that is dry to the touch or substantially dry to the touch. Thermally transferrable radiation curable protective topcoat material is applied from the print ribbon onto the plastic identification document, with at least some of the applied thermally transferrable radiation curable protective topcoat material overlapping color material previously applied to the document. Thereafter, the plastic identification document is transported into a radiation curing station along the document transport path, and radiation is applied to the applied thermally transferrable radiation curable protective topcoat material to cure the applied thermally transferrable radiation curable protective topcoat material. Thereafter, the plastic identification document is transported to a document output and the plastic identification document is output.
The identification documents described herein can be personalized plastic identification cards or plastic pages of passports. Personalized plastic identification cards described herein include, but are not limited to, financial (e.g., credit, debit, or the like) cards, access cards, driver's licenses, national identification cards, and business identification cards, and other plastic identification cards that can benefit from having high durable printing described herein. In an embodiment, the plastic identification cards may be ID-1 cards as defined by ISO/IEC 7810. However, other card formats such as ID-2 as defined by ISO/IEC 7810 are possible as well. The passport pages can be a front cover or a rear cover of the passport, or an internal page (for example a plastic page referred to as a data page) of the passport. In an embodiment, the passports may be in an ID-3 format as defined by ISO/IEC 7810.
For sake of convenience in describing the concepts herein, the following description and the drawings describe the identification document as being a plastic card. However, as indicated above, the techniques described herein are applicable to plastic pages of passports.
The term “plastic identification document” or “plastic identification card” as used throughout the specification and claims, unless indicated otherwise, refers to identification documents such as plastic cards where the document substrate can be formed entirely of plastic, or formed of a combination of plastic and non-plastic materials. In one embodiment, the cards can be sized to comply with ISO/IEC 7810 with dimensions of about 85.60 by about 53.98 millimeters (about 3% in x about 2⅛ in) and rounded corners with a radius of about 2.88-3.48 mm (about ⅛ in). As would be understood by a person of ordinary skill in the art of plastic identification cards, the cards are typically formed of multiple individual layers that form the majority of the card body or the card substrate. Similarly, the term “plastic page” of a passport refers to passport pages where the passport can be formed entirely of plastic, or formed of a combination of plastic and non-plastic materials. An example of a plastic passport page is the data page in a passport containing the personal data of the intended passport holder. The passport page may be a single layer or composed of multiple layers. Examples of plastic materials that the card or passport page, or the individual layers of the card or passport can be formed from include, but are not limited to, polycarbonate, polyvinyl chloride (PVC), polyester, acrylonitrile butadiene styrene (ABS), polyethylene terephthalate glycol (PETG), TESLIN®, combinations thereof, and other plastics. In an embodiment, the card or passport page can be formed primarily of a biodegradable material such as one or more biodegradable plastics, paper/cardboard, or other biodegradable material(s). In an embodiment, the card can be a metal card formed partially or entirely of metal.
As used herein, the term “processing” (or the like) as used throughout the specification and claims, unless indicated otherwise, is intended to encompass operations performed on a card that includes operations that result in personalizing the card as well as operations that do not result in personalizing the card. An example of a processing operation that personalizes the card is printing the cardholder's image or name on the card. An example of a processing operation that does not personalize the card is applying a laminate to the card or printing non-cardholder graphics on the card. The term “personalize” is often used in the card industry to refer to cards that undergo both personalization processing operations and non-personalization processing operations.
The system 10 in
The document input 12 can be configured to hold a plurality of plastic cards or passports waiting to be processed and that mechanically feeds the documents one by one into the system 10 using a suitable document feeder. In one embodiment, the document input 12 can be an input hopper. In another embodiment, the document input 12 can be an input slot through which individual documents are manually or automatically fed for processing. The documents are initially introduced into the one or more optional document processing stations 14 if they are present in the system. The stations 14, if present, can include a chip testing/programming device that is configured to perform contact or contactless testing of an integrated circuit chip on each document to test the functionality of the chip, as well as program the chip. Testing the functionality of the chip can include reading data from and/or writing data to the chip. In one embodiment, the chip testing/programming device can be configured to simultaneously program the chips on a plurality of cards. The construction and operation of chip testing/programming devices in document processing systems is well known in the art. The stations 14 can also include a magnetic stripe read/write testing device (when the documents are cards) that is configured to read data from and/or encode data on a magnetic stripe on each card (if the cards include a magnetic stripe). The construction and operation of magnetic stripe read/write testing devices in document processing systems is well known in the art.
The print station 16 can be any type of thermal printing mechanism that can print using the print ribbons described herein. For example, the print station 16 can be configured to perform direct-to-card thermal transfer printing (described further below in
In an embodiment, two or more print stations 16 can be provided, one print station 16 performing color printing (monochromatic or multi-color) as described further below and the other print station 16 performing printing of the topcoat described further below. In
The curing station 18 is configured to generate and apply radiation, such as ultraviolet radiation or other radiation, to radiation curable material, such as radiation curable topcoat material, applied to the card in the print station 16 to cure the radiation curable material. The curing station 18 can include a curing lamp that includes at least one radiation source or radiation emitter that emits radiation. In one embodiment, the curing lamp can be formed by one or more light emitting diodes (LEDs) that emit UV light. Additional examples of radiation sources include, but are not limited to, one or more Xenon pulsed light sources, one or more high pressure lamps, and other radiation sources. An example of a mechanism that can generate and apply curing radiation in a card personalization system is the radiation applicator used in the DATACARD® MX8100™ Card Issuance System available from Entrust Corporation of Shakopee, Minnesota
The one or more additional document processing stations 20 can be stations that are configured to perform any type of additional document processing. Examples of the additional document processing stations 20 include, but are not limited to, an embossing station having an embosser configured to emboss characters on the documents, an indent station having an indenter configured to indent one or more characters on the documents, a lamination station with a laminator configured to apply one or more laminates to the documents, a security station with a security feature applicator configured to apply one or more additional security features to one or more of the surfaces of the documents, and one or more document reorienting mechanisms/flippers configured to rotate or flip a document 180 degrees for processing on both sides of the documents.
The document output 22 can be configured to hold a plurality of documents after they have been processed. In this configuration, the document output 22 is often termed a document output hopper. The construction and operation of output hoppers is well known in the art. In another embodiment, the document output 22 can be an output slot.
In
The one or more optional document processing stations 14, the print station 16, and the curing station 18 can be arranged relative to one another in the manner indicated in
In the systems 10, 30 in
Many possible layouts for the front surface 42 are possible. For example, the front surface 42 can include a horizontal card layout, a vertical card layout, and other known layout configurations and orientations. In the illustrated example in
Referring to
Some or all of the printing on the front surface 42 and/or the printing on the rear surface 44 is at least partially overlapped or completely overlapped by a radiation curable material that is applied in the print station 16 from the print ribbon along with the color material forming the printing. Once the radiation curable material is cured, the durability (for example, abrasion resistance, chemical resistance, and adhesion) of the printing compared to the durability of printing that is not overlapped by radiation cured material is increased or enhanced. The enhanced durability is sufficient to permit the plastic card 40 to be issued to the cardholder without a protective laminate or coating applied over the entire front surface 42 and/or over the entire rear surface 44. In other words, the front surface 42 and/or the rear surface 44 can be without or devoid of a protective laminate or coating overlaying the entire front surface 42 and/or overlaying the entire rear surface 44. However, in an embodiment, a protective laminate or coating can be applied to overlay the entire front surface 18 and/or the entire rear surface 20.
Referring to
In the print station 16 of
The thermal transfer print ribbon 72 (or just print ribbon 72) that is used with the print stations 16 in
Referring to
In the example of
The panels 104a, 104b of color material can be any two color materials that one may want to apply to the plastic card. For example, the panels 104a, 104b can be two or more of black, silver, white, gray, cyan (C), magenta (M), or yellow (Y) in any order.
The radiation curable topcoat material of the T-panels 102e in
The radiation curable topcoat material may also be described as being print receptive. Print receptive means that the radiation curable topcoat material is suitable for receiving color material from a print ribbon (or from a drop-on-demand print head) to form printing on the radiation curable topcoat material where the resulting print quality on the radiation curable topcoat material is considered sufficient to allow the resulting plastic card to be issued to the intended cardholder. A typical topcoat material used with plastic cards and other personalized identification documents is not printed on and is not considered in the plastic card industry to be print receptive. However, the radiation curable topcoat material described herein is print receptive and could be printed on if one chooses to do so.
In one non-limiting embodiment, the thermal transfer print ribbon 72 can have the following construction. However, other constructions are possible.
Carrier Film 100:
Materials for the carrier film 100 can include, but are not limited to, polyester, polycarbonate, polyolefin, polyurethane, acetate, and others, individually and in combinations thereof. It is desirable that the carrier film 100 has sufficient heat and dimensional stability during the coating, drying, printing and transfer process. In one embodiment, the carrier film 100 can have a thickness of between about 4.0 microns to about 8.0 microns. In another embodiment, the carrier film 100 can have a thickness of between about 4.0 microns to about 6.0 microns.
Color Panels:
The construction and formulation of the color panels, which may be dye-based inks and/or pigment inks, can be standard and known in the art.
T-Panels 102e:
The material of the T-panels 102e can include, but is not limited to, a mixture of: (i) one or more UV or other radiation curable acrylates, urethane acrylates, epoxy acrylates, or acrylate oligomers, individually and in combinations thereof; (ii) one or more thermoplastic vinyls, acrylics, acetates, urethanes, or polyesters, individually and in combinations thereof; and (iii) one or more photoinitiators. Optionally, other additives can be included such as surfactants, wax, stabilizers, inhibitors, and others to improve processing and stability of the T-panels 102e of the print ribbon 72. Optionally, fillers like silica, aluminum oxide and others may be added to improve toughness. Each resulting T-panel 102e is dry to the touch or substantially dry to the touch.
A solution of these components is made in a suitable solvent system and coated over the carrier film 100 with conventional coating methods like gravure, wire wound rod or slot die coating. When dried after coating, the layer of material forming each T-panel 102e should be tack-free or dry to the touch or substantially dry to the touch. This dry to the touch layer is radiation cured after it has been transferred to the desired substrate like the plastic card or the retransfer ribbon.
In one embodiment, each T-panel 102e can have a thickness of between about 3.0 microns to about 12.0 microns. In another embodiment, each T-panel 102e can have a thickness of between about 5.0 microns to about 10.0 microns.
In an embodiment, each T-panel 102e can comprise at least the following components: one or more radiation curable monomers preferably tetrafunctional or greater; one or more photoinitiators; one or more non-functional polymers; one or more radiation-curable acrylic polymers; one or more heat-curable monomers; one or more hydroxy-functional polymers; one or more thermal initiators; and one or more silica sols.
The one or more radiation curable monomers, commonly an acrylic monomer, can comprise an average functionality of four or larger, or a majority of the at least one radiation curable monomer has an average functionality of four or larger. The radiation curable monomer may comprise an acrylic monomer, such as, for example, an aliphatic urethane hexaacrylate, or an acrylic monomer with hydroxyl functionality, such as, for example, dipentaerythritolhexaacrylate (DPHA).
The one or more photoinitiators absorb radiation in the actinic wave band from 220 nm to 410 nm that is generated by conventional mercury UV lamps, or absorb radiation at longer select actinic wavelengths, typically 395 nm, 385 nm and 365 nm, that are emitted by LED lamps. An example of a photoinitiator that can be used includes, but is no limited to, bis-acylphosphineoxide (BAPO).
Examples of non-functional polymers that can be used include, but are not limited to, polyester, vinyl copolymers and polyacrylic polymers, alone or in combination. These components aid in overall film formation and adhesive properties of thermally-transferrable radiation-curable topcoats.
The one or more radiation-curable acrylic polymers can include, but are not limited to, one or more UV-curable acrylic polymers which exist in solid-phase at room temperature and can be prepared using a two-step reaction: (1) preparing acrylic polymers that have pendant isocyanate functionality using 2-methacryloyloxyethyl isocyanate (MOI) as a co-monomer; and then (2) reacting the pendant isocyanate groups with hydroxy-functional epoxide, oxetane, or benzophenone.
The one or more hydroxy-functional polymers are polymers comprising hydroxyl groups that are capable of reacting with reactive groups on heat curable monomers, such as, for example, ether groups, to form covalent bonds. Examples of hydroxy-functional polymers that can be used include, but are not limited to, polyacrylic polyols, cellulose ester polyols, polyether polyols, polyester polyols and polyvinyl alcohols.
The one or more heat-curable monomers that can be used can include, but are not limited to, isocyanates, epoxies, phenolics, amines, silanes, and monomers with one or more ether groups such as, one, two, three, or more ether groups. The ether groups may, for example, include one or more methoxy, ethoxy, or other groups. The ether groups may react with other functional groups, such as, for example, hydroxyl groups, or they may react with other ether groups. The reactions may result in polymerization or cross-linking. Heat-curable monomers with aromatic or heteroaromatic rings, such as, for example, functionalized melamine monomers, may provide improved coating compatibility with substrates such as polyethylene terephthalate. An example of a heat-curable monomer that can be used includes, but is not limited to, hexamethoxymethylmelamine (HMMM).
The one or more thermal initiators promote polymerization and cross-linking reactions. Thermal initiators accomplish this function by lowering the activation energy (Ea) for a given step reaction, providing a different route. The different route allows bond rearrangements to convert reactants to products more easily, with a lower energy input. In a given time interval, the presence of a thermal initiator allows a greater proportion of the reactant species to pick up sufficient energy to pass through the transition state and become products. An example of a thermal initiator that can be used includes, but is not limited to, is para-toluene sulfonic acid (PTSA).
The one or more silica sols impart hardness and heat resistance to the thermally-transferrable radiation-curable topcoat. An example of a silica sol that can be used includes, but is not limited to, a colloidal silica sol that allows for high transparency under visible light when dispersed evenly in liquid media.
The thermally-transferrable radiation-curable topcoat may also include one or more organic solvents used for purposes such as controlling solution viscosity, improving wetting and substrate coating. Examples of organic solvents that can be used include, but are not limited to, ketones, esters, and alcohols, such as, for example, methyl ethyl ketone, butyl acetate and isopropanol.
Natural or synthetic waxes may be added to the topcoat to increase surface slip.
The topcoat may also include one or more reactive silanes as a coupling agent for silica sols and heat-curable monomer to improve tensile properties.
Optional Release layer:
An optional release layer can be provided between each T-panel 102e and the carrier film 100 to facilitate the release of the radiation curable material of the T-panels 102e from the carrier film 100. The optional release layer can include, but is not limited to, a polyester, an acrylic or a wax based coating that can be applied with conventional coating methods like gravure, wire wound rod or slot die coating. The optional release layer may be thermoplastic or cured with heat or radiation.
In one embodiment, the optional release layer may have a thickness of between about 0.1 microns to about 4.0 microns. In another embodiment, the optional release layer may have a thickness of about 0.1 microns to about 2.0 microns.
In one embodiment, the optional release layer may include one or more of a thermally-cured melamine such as an amino cross-linker; a thermally-cured silicone; and a UV-cured silicone.
The thermally-cured amino-cross linked release system can contain at least the following: one or more heat-curable amino resin monomers; one or more hydroxy-functional polymers; and one or more thermal initiators. The one or more heat curable amino resin monomers may include monomers with one or more ether groups such as, one, two, three, or more ether groups. The ether groups may, for example, include one or more methoxy, ethoxy, or other groups. The ether groups may react with other functional groups such as, for example, hydroxyl groups, or they may react with other ether groups. The reactions may result in polymerization or cross-linking. Heat-curable monomers with aromatic or heteroaromatic rings, such as, for example, functionalized melamine monomers, may provide improved coating compatibility with substrates such as polyethylene terephthalate. An example of a thermally-cured monomer that can be used is hexamethoxymethylmelamine (HMMM). Hydroxy-functional polymers are polymers comprising hydroxyl groups that are capable of reacting with reactive groups on heat curable monomers, such as, for example, ether groups, to form covalent bonds. Hydroxy-functional polymers may be characterized by their hydroxyl content. Examples of hydroxy-functional polymers that can be used include, but are not limited to, polyacrylic polyols, cellulose ester polyols, polyether polyols, polyester polyols and polyvinyl alcohols. Thermal initiators promote polymerization and cross-linking reactions. Thermal initiators accomplish this function by lowering the activation energy (Ea) for a given step reaction, providing a different route. The different route allows bond rearrangements to convert reactants to products more easily, with a lower energy input. In a given time interval, the presence of a thermal initiator allows a greater proportion of the reactant species to pick up sufficient energy to pass through the transition state and become products. An exemplary thermal initiator is para-toluene sulfonic acid (PTSA). The thermally-cured amino-crosslinked release coating may also include organic solvents which control solution viscosity, improve wetting and substrate coating. Examples of organic solvents that can be used include, but are not limited to, ketones, esters, and alcohols, such as, for example, methyl ethyl ketone, butyl acetate and isopropanol. Surfactants may be added to the release coating to improve wetting of the release coating. Hydroxyl-functional polysiloxanes are exemplary wetting agents for heat-cured coatings because they will form covalent bonds with heat-cured monomers during the drying process at elevated temperatures, resisting migration of surfactant molecules to the backside of the carrier film in roll form under long-term storage conditions.
The thermally-cured silicone can comprise at least the following components: one or more silicone polymers with vinyl groups; one or more silicone hydride crosslinkers; and one or more thermal initiators, preferably a platinum catalyst. Vinyl-functional polysiloxanes undergo thermally-induced addition polymerization upon exposure to elevated temperatures in the presence of a platinum catalyst. Thermally-cured silicone polymers fall under four general categories: 1) silicone polymers with terminal vinyl functionality (at chain ends), 2) silicone polymers with pendent vinyl functionality (at side of polymer backbone), 3) silicone polymers varying in chain length, and 4) silicone hydride crosslinker type. The ratio of various silicone polymers with vinyl or methylhydrogen groups over these four general categories dictates the relative ratio of vinyl groups to silicone groups in the thermally-cured silicone release layer. It is this ratio that largely determines the thermally-cured release composite ultimate performance properties (i.e: snug release to easy release). Thermal initiators promote polymerization and cross-linking reactions. Thermal initiators accomplish this function by lowering the activation energy (Ea) for a given step reaction, providing a different route. The different route allows bond rearrangements to convert reactants to products more easily, with a lower energy input. In a given time interval, the presence of a thermal initiator allows a greater proportion of the reactant species to pick up sufficient energy to pass through the transition state and become products. An example of a thermal initiator that can be used is Karstedt's catalyst Pt2[(Me2SiCH═CH2)2O]3. The thermally-cured silicone release coating may also include organic solvents used to control solution viscosity, improve wetting and substrate coating. Examples of organic solvents that can be used include, but are not limited to, ketones, esters, and alcohols, such as, for example, methyl ethyl ketone, butyl acetate and isopropanol. Further, petroleum solvents such as n-heptane, isooctane and VM&P Naphtha may be used as diluents in the thermally-curable silicone release coating.
The UV-cured silicone release coating may comprise at least the following components: one or more silicone polymers with acrylate or epoxy groups, present as a blend; one or more radiation curable monomers preferably tetrafunctional or greater; and one or more photoinitiators. Acrylate-functional polysiloxanes undergo free-radically-induced polymerization upon exposure to UV light in the presence of a photoinitiator. Epoxy-functional polysiloxanes undergo cationically-induced polymerization upon exposure to UV light in the presence of a cationic photoinitiator. Both silicone acrylate and silicone epoxy polymer units fall under three general categories: 1) silicone polymers with terminal acrylate or epoxy functionality (at chain ends), 2) silicone polymers with pendent acrylate or pendent epoxy functionality (at side of polymer backbone), and 3) silicone acrylate or silicone epoxy polymers varying in chain length. The ratio of silicone acrylate or silicone epoxy polymers over these three general categories dictates the relative ratio of acrylate or epoxy groups to silicone groups in the UV-cured silicone release layer.
The one or more radiation curable monomers can comprise an average functionality of four or larger, or a majority of one or more radiation curable monomers has an average functionality of four or larger. In at least some embodiments, the radiation curable monomer may comprise an acrylic monomer, such as, for example, an aliphatic urethane hexaacrylate, or an acrylic monomer with hydroxyl functionality, such as, for example, dipentaerythritolhexaacrylate (DPHA). Photoinitiators used for the UV-cured silicone release coating absorbs radiation in the actinic wave band from 220 nm to 410 nm that is generated by conventional mercury UV lamps, or absorb at longer select actinic wavelengths, typically 395 nm, 385 nm and 365 nm, that are emitted by LED lamps. An example of a UV photoinitiator for both conventional UV-cure and UV-LED cure that can be used is bis-acylphosphineoxide (B APO). Cationic photoinitiators are strong acid generators derived from sulfonium or iodonium salts comprised of a cationic and anionic pair. An example of a cationic photoinitiator that can be used is triarylsulfonium hexafluoroantimonate salt. The UV-curable silicone release coating may also include organic solvents used for controlling solution viscosity, improve wetting and substrate coating. Examples of organic solvents that can be used include, but are not limited to, ketones, esters, and alcohols, such as, for example, methyl ethyl ketone, butyl acetate and isopropanol. Further, petroleum solvents such as n-heptane, isooctane and VM&P Naphtha may be used as diluents in the UV-cured silicone release coating.
Optional Adhesive Layer:
An optional adhesive layer can be added over each T-panel 102e to enhance the adhesion of the radiation curable material to the substrate such as the plastic card or a retransfer ribbon. The optional adhesive layer can be made of a single resin or a mixture of acrylates, polyurethanes, polyesters, vinyls, acetates or epoxies. The optional adhesive layer can be coated with conventional coating methods like gravure, wire wound rod or slot die coating. The optional adhesive layer may be thermoplastic or cured with heat or radiation.
In one embodiment, the optional adhesive layer may have a thickness of between about 1.0 microns to about 5.0 microns. In another embodiment, the optional adhesive layer may have a thickness of between about 1.0 microns to about 3.0 microns.
The print ribbon 72 may also optionally include a backcoat 122 (depicted in broken lines in
The thermally-cured melamine can comprise a thermally-cured amino-crosslinked backcoat with at least the following components: one or more heat-curable amino resin monomers; and one or more hydroxy-functional polymers; and one or more thermal initiators. The one or more heat curable amino resin monomers may include, but are not limited to, monomers with one or more ether groups such as, one, two, three, or more ether groups. The ether groups may, for example, include one or more methoxy, ethoxy, or other groups. The ether groups may react with other functional groups such as, for example, hydroxyl groups, or they may react with other ether groups. The reactions may result in polymerization or cross-linking. Heat-curable monomers with aromatic or heteroaromatic rings, such as, for example, functionalized melamine monomers, may provide improved coating compatibility with such substrates as polyethylene terephthalate. An example of a heat-curable monomer that can be used is hexamethoxymethylmelamine (HMMM). The one or more hydroxy-functional polymers are polymers comprising hydroxyl groups that are capable of reacting with reactive groups on heat curable monomers, such as, for example, ether groups, to form covalent bonds. Examples of hydroxy-functional polymers that can be used include, but are not limited to, polyacrylic polyols, cellulose ester polyols, polyether polyols, polyester polyols and polyvinyl alcohols. The one or more thermal initiators promote polymerization and cross-linking reactions. Thermal initiators accomplish this function by lowering the activation energy (Ea) for a given step reaction, providing a different route. The different route allows bond rearrangements to convert reactants to products more easily, with a lower energy input. In a given time interval, the presence of a thermal initiator allows a greater proportion of the reactant species to pick up sufficient energy to pass through the transition state and become products. An example of a thermal initiator that can be used includes, but is not limited to, para-toluene sulfonic acid (PTSA). The thermally-cured amino-crosslinked backcoat may also include organic solvents used for purposes such as controlling solution viscosity, improving wetting and substrate coating. Examples of organic solvents that can be used include, but are not limited to, ketones, esters, and alcohols, such as, for example, methyl ethyl ketone, butyl acetate and isopropanol. Surfactants may be added to the backcoat to improve wetting of backcoat coatings. Hydroxyl-functional polysiloxanes are exemplary wetting agents for heat-cured coatings because they will form covalent bonds with heat-cured monomers during the drying process at elevated temperatures, resisting migration of surfactant molecules to the coating on the front face of the carrier film in roll form under long-term storage conditions.
The thermally-cured silicone backcoat can comprise at least the following: one or more silicone polymers with vinyl groups; one or more silicone hydride crosslinkers; and one or more thermal initiators, preferably a platinum catalyst. Vinyl-functional polysiloxanes undergo thermally-induced addition polymerization upon exposure to elevated temperatures in the presence of a platinum catalyst. Thermally-cured silicone polymer units fall under four general categories: 1) silicone polymers with terminal vinyl functionality (at chain ends), 2) silicone polymers with pendent vinyl functionality (at side of polymer backbone), 3) silicone polymers varying in chain length, and 4) silicone hydride crosslinker type. The ratio of various silicone polymers with vinyl or methylhydrogen groups over these four general categories dictates the relative ratio of vinyl groups to silicone groups in the thermally-cured silicone backcoat. Thermal initiators promote polymerization and cross-linking reactions. Thermal initiators accomplish this function by lowering the activation energy (Ea) for a given step reaction, providing a different route. The different route allows bond rearrangements to convert reactants to products more easily, with a lower energy input. In a given time interval, the presence of a thermal initiator allows a greater proportion of the reactant species to pick up sufficient energy to pass through the transition state and become products. An example of a thermal initiator that can be used is Karstedt's catalyst Pt2[(Me2SiCH═CH2)2O]3. The thermally-cured silicone backcoat may also include organic solvents used for such purposes as controlling solution viscosity, improving wetting and substrate coating. Examples of organic solvents that can be used include, but are not limited to, ketones, esters, and alcohols, such as, for example, methyl ethyl ketone, butyl acetate and isopropanol. Further, petroleum solvents such as n-heptane, isooctane and VM&P Naphtha may be used as effective diluents in the thermally-curable silicone backcoat.
The UV-cured silicone backcoat can comprise at least the following: one or more silicone polymers with acrylate or epoxy groups; one or more radiation curable monomers preferably tetrafunctional or greater; and one or more photoinitiators. Acrylate-functional polysiloxanes undergo free-radically-induced polymerization upon exposure to UV light in the presence of a photoinitiator. Epoxy-functional polysiloxanes undergo cationically-induced polymerization upon exposure to UV light in the presence of a cationic photoinitiator. Both silicone acrylate and silicone epoxy polymer units fall under three general categories: 1) silicone polymers with terminal acrylate or epoxy functionality (at chain ends), 2) silicone polymers with pendent acrylate or pendent epoxy functionality (at side of polymer backbone), and 3) silicone acrylate or silicone epoxy polymers varying in chain length. The ratio of silicone acrylate or silicone epoxy polymers over these three general categories dictates the relative ratio of acrylate or epoxy groups to silicone groups in the UV-cured backcoat. The radiation curable monomers can comprise an average functionality of four or larger, or a majority of the at least one radiation curable monomer has an average functionality of four or larger. The radiation curable monomer may comprise an acrylic monomer, such as, for example, an aliphatic urethane hexaacrylate, or an acrylic monomer with hydroxyl functionality, such as, for example, dipentaerythritolhexaacrylate (DPHA). The one or more photoinitiators absorb radiation in the actinic wave band from 220 nm to 410 nm that is generated by conventional mercury UV lamps, absorb at longer select actinic wavelengths, typically 395 nm, 385 nm and 365 nm, that are emitted by LED lamps. An example of a UV photoinitiator for both conventional UV-cure and UV-LED cure that be used includes, but is not limited to, bis-acylphosphineoxide (BAPO). Cationic photoinitiators are strong acid generators derived from sulfonium or iodonium salts comprised of a cationic and anionic pair. An example of a cationic photoinitiator that can be used includes, but is not limited to, triarylsulfonium hexafluoroantimonate salt. The UV-curable silicone backcoat may also include organic solvents used for such purposes as controlling solution viscosity, improving wetting and substrate coating. Examples of organic solvents that can be used include, but are not limited to, ketones, esters, and alcohols, such as, for example, methyl ethyl ketone, butyl acetate and isopropanol. Further, petroleum solvents such as n-heptane, isooctane and VM&P Naphtha may be used as effective diluents in the UV-curable silicone backcoat.
Once the radiation curable topcoat material from the T-panel 102e is applied, the card is then transported to the curing station 18 and radiation is applied to the radiation curable topcoat material to cure the topcoat material. The radiation used to cure the radiation curable topcoat material can be any radiation that is suitable for curing the radiation curable topcoat material. For example, in one embodiment, the radiation can be UV radiation. Once cured, the topcoat material protects the underlying printing and increasing the durability of the underlying printing. If the color material from the color material panels 102a-d is also radiation curable, the color material may also be radiation cured at the same time as the topcoat material. Alternatively, the color material from the panels 102a-d may be applied and then cured, followed by applying the radiation curable topcoat material which is then cured in a separate curing step.
The radiation curable topcoat material from the T-panel 102e is preferably transparent or translucent before and after curing. Alternatively, the radiation curable topcoat material from the T-panel 102e may be opaque after curing (and optionally prior to being cured). The radiation curable topcoat material may also include security features therein such as fluorescent material and/or an optical variable device such as a hologram or optically variable pigment inks.
Referring to
The examples disclosed in this application are to be considered in all respects as illustrative and not limitative. The scope of the invention is indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.
Number | Date | Country | |
---|---|---|---|
63374302 | Sep 2022 | US |