Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/40—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography
  • B41M5/42—Intermediate, backcoat, or covering layers
  • B41M5/426—Intermediate, backcoat, or covering layers characterised by inorganic compounds, e.g. metals, metal salts, metal complexes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M3/00—Printing processes to produce particular kinds of printed work, e.g. patterns
  • B41M3/14—Security printing
  • B41M3/144—Security printing using fluorescent, luminescent or iridescent effects

Definitions

• the invention relates to a heat-sensitive recording material which has at least one web-shaped substrate, a heat-sensitive recording layer and an intermediate layer located between the substrate and the heat-sensitive recording layer.
• the proposed recording material should contain at least one authentication feature.
• the invention also aims at a method for producing such a thermosensitive recording material.
• Recording materials determine daily life in today's society and especially within today's professional life. Recording materials, in particular with paper as a web-shaped substrate and with at least one heat-sensitive recording layer on at least one of the two sides of the web-shaped substrate are known since the early years chemically reactive recording materials and enjoy an unbroken popularity, which is due, inter alia, that their use, for example Entry, flight and travel tickets for ticket issuers are associated with great benefits. Because the color-forming components are stuck in the recording material itself in the heat-sensitive recording method, the toner and color-cartridge-free printers, which no longer need to be regularly controlled and maintained by anyone, can be set up in large numbers. Thus, this innovative technology has prevailed in particular in public passenger transport, buses and trains as well as in air traffic, but also at stadium and museum funds as well as parking ticket issuers.
• a watermark is generally understood to mean a drawing in the paper, whereby a distinction is made between genuine watermarks which are produced by displacement (so-called light watermarks) or by enrichment (so-called shadow watermarks).
• the fiber stock may be produced using a dandy cutter in the wire section of a paper machine, so-called molten watermarks created by embossing still-wet paper in the press section of a paper machine, and finally spurious watermarks, either by printing on the paper finished paper outside the paper machine with a colorless paint or by embossing the finished paper outside the paper machine are created.
• genuine watermarks are also so popular because they seem to give the recording material equipped with them a particularly high-quality character.
• recording materials which, as an authenticity-proofing security feature, usually have fluorescent components under special light.
• the present invention relates in general terms to recording materials having this type of authenticity-proofing security features.
• the authenticity-detecting control of recording materials with fluorescent components usually requires a minimum of technical equipment, be it in the form of special light sources, either or alternatively in the form of suitable detectors and display devices.
• This alleged disadvantage of not everywhere and immediately possible authenticity-proofing control is counteracted by the much more meaningful and much worse to falsify control result for recording materials with fluorescent components.
• recording materials with fluorescent components are known as an authenticity-proofing security feature in a thoroughly complex manner.
• the EP 1 233 106 B1 a security feature generally in the form of a component, there referred to as a segment, with linearly polarized photoluminescence before then It.
• the EP 1 446 528 B1 should be incorporated into a paper or paper-like structure.
• the components known in this way which are to be used as authenticity-proofing security feature, are aimed at organic basic substances, usually in the form of fibers, which are labeled with organic fluorescent dyes as well. By stretching The base substances labeled in this way result in polarization effects, which are the underlying and / or characteristic constituents of the abovementioned publications.
• a value document such as a banknote, identity card or the like
• a value document such as a banknote, identity card or the like
• the first security feature is in the form of an inorganic luminescent substance
• the second security feature is in the form of an organic luminescent substance.
• This authenticity-detecting security feature based on luminescent components is intended to be incorporated on the side of a web-shaped substrate on which the heat-sensitive recording layer itself is formed, so that the security feature of the recording material proposed here as part of its intended use as a public transport ticket, on buses and as well as in air traffic, but also as a ticket to stadium and museum cash registers is particularly easy and quickly detectable and is directly related to the induced by the action of heat typeface.
• the luminescent components are incorporated as inorganic constituents in the at least one intermediate layer.
• the inorganic constituents are fluorescent components, which means that the emission of the authenticity-detecting radiation, preferably in the form of infrared radiation, immediately after the start of excitation of the components usually by high-energy radiation, for example in Form of UV light and / or in the form of infrared rays, as they can be emitted from lasers, laser diodes and LED's, begins, and that the emission of authenticity-detecting radiation soon after end of excitation of the components also ends again, as evidence of authenticity sufficient of a present recording material and which is usually preferred by the users of the recording material proposed here.
• the invention is in no way limited to such fluorescent components: even after long excitation end nachstrahlende components are quite possible and can represent a preferred depending on the purpose embodiment.
• the barrier-forming interlayer contains ethylene-vinyl alcohol copolymer (EVOH).
• EVOH ethylene-vinyl alcohol copolymer
• the reason for the preferred embodiment of the barrier layer disposed between the substrate and the heat-sensitive recording layer is to protect the thermosensitive recording layer effectively from chemicals which cause either an unwanted color forming reaction in the recording layer or a weakening of a typeface to be formed or formed in the recording layer can and may also be contained in larger amounts in the substrate and / or applied to the back of the substrate.
• the above-mentioned chemicals are primarily intended to include but are not limited to plasticizers, and more particularly organic solvents.
• the chemicals mentioned can come into contact with the recording material proposed here on the one hand in the context of its intended use as a ticket or as a ticket or as part of applied authentification-proofing test tinctures.
• the barrier-forming intermediate layer of the proposed heat-sensitive recording material formed within this first preferred embodiment preferably comprises at least 90% by weight, most preferably at least 98% by weight, based on the total weight of the barrier-forming intermediate layer, of the ethylene-vinyl alcohol copolymer.
• Further constituents of this barrier-forming intermediate layer can also be defoamers, for example and / or means for stabilizing the color curtain in a possible application of the second coating composition by means of curtain or slide coater.
• this pigmented intermediate layer has at least one organic pigment and at least one inorganic pigment.
• the at least one inorganic pigment is selected from the list comprising: kaolin, silicon (di) oxide, bentonite, talc, calcium carbonate, and aluminum (hydr) oxide, and here especially boehmite. It is possible that not only one inorganic pigment but several different inorganic pigments are incorporated into the third coating composition for forming the pigmented intermediate layer.
• the inorganic pigments are preferably selected individually or in combination with one another from the list, comprising: kaolin, silicon (di) oxide, bentonite, talc, calcium carbonate and aluminum (hydr) oxide and, in particular, boehmite.
• the ratio between organic and inorganic pigment is a compromise of the effects caused by the two types of pigments, which is particularly advantageously solved when the pigment mixture to 5 to 30 wt .-% or better to 8 to 20 wt .-% of organic and 95 to 70 wt .-% or better to 92 to 80 wt .-% consists of inorganic pigment.
• the organic pigments have a wall of thermoplastic resin which preferably comprises (meth) acrylonitrile copolymer, polyvinyl chloride, polyvinylidene chloride, polystyrene, styrene acrylate, polyacrylonitrile or polyacrylic acid ester.
• thermoplastic resin which preferably comprises (meth) acrylonitrile copolymer, polyvinyl chloride, polyvinylidene chloride, polystyrene, styrene acrylate, polyacrylonitrile or polyacrylic acid ester.
• Pigment mixtures of different organic pigments are conceivable.
• a glass transition temperature greater than or equal to 100 ° C and preferably greater than or equal to 105 ° C was found to be advantageous because below these temperatures, an increased degree of yellowing was detected.
• the third coating composition contains at least one binder, preferably based on a synthetic polymer, wherein, for example, styrene-butadiene latex gives particularly good results.
• a synthetic binder with the admixture of at least one natural polymer, more preferably starch, is a particularly suitable embodiment. Numerous tests have also found that with a binder to pigment ratio within the third coating composition is between 3: 7 and 1: 9, in each case based on wt .-%, a particularly suitable embodiment is present.
• the heat-sensitive recording layer formed from a first coating composition preferably comprises at least one organic dye precursor and at least one organic dye acceptor, wherein dye precursor and dye acceptor react color-forming under the action of heat.
• Preferred dye precursors are preferably those selected from the list comprising: 3-diethylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3- (N-methyl-N- propyl) amino-6-methyl-7-anilinofluoran, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluoran, 3- (N-methyl-N-cyclohexyl) amino-6-methyl- 7-anilinofluoran, 3- (N-ethyl-N-tolyl) amino-6-methyl-7-anilinofluoran and 3- (N-ethyl-N-tetrahydrofuryl) amino-6-methyl-7-anilinofluoran. All Particularly preferred is 3-dibutylamino-6-methyl-7-anilinofluoran - also known as ODB-2.
• the first coating composition has more than one dye precursor, each selected from the dye precursors listed in the above paragraph.
• Suitable binders for incorporation into the heat-sensitive recording layer are, for example, water-soluble binders such as starch, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, in particular polyvinyl alcohols, modified polyvinyl alcohols, sodium polyacrylates, acrylamide-acrylate copolymers, acrylamide-acrylate-methacrylate terpolymers, in particular ethylene- Vinyl alcohol copolymers, alkali metal salts of styrene-maleic anhydride copolymers or ethylene-maleic anhydride copolymers, which can be used alone or in combination with one another; Water-insoluble latex binders such as styrene-butadiene copolymers, acrylonitrile-butadiene copolymers and methyl acrylate-butadiene copolymers also offer themselves as binders for incorporation into the heat-sensitive recording layer at.
• water-soluble binders such as starch,
• polyvinyl alcohol in conjunction with ethylene-vinyl alcohol copolymers as particularly preferred binders whose combination as the sole binder in a proportion of 12 to 27.5 wt .-%, based on the total weight of the first coating composition, in the heat-sensitive Recording layer are involved.
• the first coating composition for forming the thermosensitive recording layer may further contain lubricants and release agents such as metal salts of higher fatty acids, for example, zinc stearate, calcium stearate and waxes such as paraffin, oxidized paraffin , Polyethylene, polyethylene oxide, stearamides and castor wax.
• Further constituents of the recording layer may be, for example, pigments, preferably inorganic pigments such as, for example, kaolin, silicon (di) oxide, bentonite, talc, calcium carbonate and aluminum (hydr) oxide and here in particular boehmite.
• the present inventors recognized that calcined kaolin should be rejected because of its high abrasiveness for incorporation into the first coating composition for forming the thermosensitive recording layer, particularly when a protective layer covering the thermosensitive recording layer is not provided.
• calcium carbonate which is preferably incorporated in an amount of 10 to 18 wt .-%, based on the total weight of the first coating composition in the heat-sensitive recording layer, is preferred.
• the heat-sensitive recording material proposed here has a protective layer covering the heat-sensitive recording layer.
• a protective layer is considered particularly particularly preferred when the proposed heat-sensitive recording material according to the first preferred embodiment according to paragraphs [0017] to [0021 or the third preferred embodiment according to paragraph [0030] has a barrier-forming intermediate layer.
• a protective layer which is produced in the same way as the barrier-forming intermediate layer based on ethylene-vinyl alcohol copolymer (EVOH) and which then preferably contains at least 90% by weight, very particularly preferably at least 98% by weight. each based on the total weight of such a protective layer contains the ethylene-vinyl alcohol copolymer, very good results could be achieved with a protective layer having at least 60 wt .-%, particularly preferably at least 85 wt .-%, diacetone-modified polyvinyl alcohol as a binder, wherein the two values relate to the weight% of the total binder content in the protective layer.
• a protective layer constructed in this way is considered to be very particularly preferred in the context of the present invention.
• the protective layer of the proposed heat-sensitive recording material which is very particularly preferred in this way may, in addition to the diacetone-modified polyvinyl alcohol in a first possible embodiment, comprise further binders, in particular mixtures of different carboxyl group-modified or silanol-modified polyvinyl alcohols. These then make up a maximum of 40 wt .-%, more preferably only a maximum of 15 wt .-%, again, based on the total amount of binder in the protective layer.
• the protective layer of the proposed thermosensitive recording material has as binder exclusively diacetone-modified polyvinyl alcohol.
• the binder content in the protective layer be in the range of 35 to 65% by weight based on the total weight of the protective layer.
• Suitable crosslinking aids in the protective layer are, in particular, those selected from the group comprising: boric acid, polyamine, epoxy resin, dialdehyde, formaldehyde oligomers, epiochlorohydrin resin, adipic dihydrazide, dimethylurea, melamine-formaldehyde. It is also possible to use mixtures of different crosslinking aids.
• the ratio of the weight% of the binder, especially the diacetone-modified polyvinyl alcohol, to the crosslinking aid is in a range of 20: 1 to 5: 1, and more preferably in a range of 12: 1 to 7 : 1 is.
• the protective layer additionally contains an inorganic pigment.
• the inorganic pigment is selected from the group consisting of silica, aluminum hydroxide, bentonite, calcium carbonate, non-calcined kaolin or a mixture of said inorganic pigments.
• the invention also relates, to the same extent, to processes for producing a heat-sensitive recording material in all the embodiments and variants already proposed here.
• the formation of the web-like substrate is done for example on a paper machine, in which at least one upstream Mischbütte a paper pulp of different pulps, optionally groundwood, fillers and water is applied and where to this paper pulp before being fed to the paper machine preferably further ingredients such as resin glue for engine sizing and other customary additives, such as pigments, shading dyes and / or optical brighteners are added.
• a paper machine is a fourdrinier paper machine, it provides a preferred embodiment when a dandy is placed above the papermachine screen or other suitable location in the paper machine, with the aid of which a true watermark is pressed into the still wet substrate.
• the second coating composition for forming the barrier-forming intermediate layer is preferably applied in particular by means of non-contact application devices, such as air brushes and curtain coater, without being limited to these in any way.
• the coating weight for the barrier-forming intermediate layer is preferably in a range from 0.9 to 5.0 g / m 2 , very particularly preferably in a range from 1.5 to 3.5 g / m 2 .
• the third coating composition for forming the pigmented intermediate layer is applied by means of a leveling coating process selected from the list comprising: roller coater, doctor blade or doctor blade coater.
• the intermediate layer in addition to its other tasks such as serving as a carrier of authenticity-detecting security feature on the basis of luminescent components, make a positive contribution to the leveling of the substrate surface, bringing the amount to be applied Mass of the first coating composition for forming the heat-sensitive recording layer reduced.
• the subsequent drying of the coating composition of this third coating composition is usually carried out by a method in which heat is supplied, as is done by hot-air floatation dryer or contact dryer. Proven is also a combination of the listed dry processes.
• a preferred range between 5 and 20 g / m 2 and even better between 7 and 12 g / m 2 has proven.
• At least one intermediate layer is applied to the web-shaped substrate - selected from the barrier-forming intermediate layer and the pigmented intermediate layer - and then applying the prepared first coating composition for forming a heat-sensitive recording layer.
• the first coating composition is preferably applied by means of a coating process, selected from the list, comprising: roller blade coater, knife coater, curtain coater or air brush.
• the first coating composition used to form the recording layer is preferably aqueous.
• the subsequent drying of the first coating composition is usually carried out by a method in which heat is supplied, as is done by hot-air floatation dryer or contact dryer. Proven is also a combination of the listed dry processes.
• the basis weight of the heat-sensitive recording layer is preferably from 2 to 6 g / m 2, and more preferably from 2.2 to 4.8 g / m 2 .
• a coating device for applying the heat-sensitive recording layer covering formed from a fourth coating composition protective layer are particularly suitable for rotary blade coater, knife coater, curtain coater or air brush.
• the basis weight of the protective layer is preferably between 1.0 and 3.0 g / m 2 and more preferably between 1.6 and 2.3 g / m 2 .
• the method for producing a heat-sensitive recording material provides in a preferred variant for smoothing the substrate with the now applied and dried first, second and / or third and optionally fourth coating compositions.
• the aim of such a smoothing by a calender or a calender is to create a flattened, possibly shiny surface, with which applied typefaces appear more colorful and lively.
• a smoother surface of the heat-sensitive recording layer or the optionally present protective layer by improved contact with the thermal head supports the heat transfer and thus the sensitivity of this heat-sensitive recording layer.
• the recording material finished in this way is preferably rolled up on a spool and is then ready for use according to the customer's wishes, in particular as a ticket.
• thermosensitive recording material in addition to the disclosed methods for producing a thermosensitive recording material in all the embodiments and variants already proposed herein and in addition to the recording material itself, also claims the use of the here proposed record material for issuing tickets and / or tickets at a correspondingly suitable thermal printer.
• Numerous tests and test series of heat-sensitive recording materials according to the embodiments and variants proposed here have been able to show their superior effect in their use as a public transport ticket, on buses and trains as well as in air traffic, but also as tickets to stadium and museum funds.
• the surface mass,% by weight (% by weight) and parts by weight (parts by weight) given in the specification and claims refer to the "atro" weight, respectively. absolutely dry parts by weight.
• the relevant figures are calculated from the "lutro" weight, i. air-dry parts by weight, minus the proportion by weight of water around and inside the pigments in their form of delivery.

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• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Heat Sensitive Colour Forming Recording (AREA)

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• 2011
  • 2011-04-27 DE DE201110018852 patent/DE102011018852A1/de not_active Withdrawn
  • 2011-06-10 EP EP11169635A patent/EP2517888A1/fr not_active Withdrawn
• 2012
  • 2012-04-25 EP EP12165461A patent/EP2517889A1/fr not_active Withdrawn

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