DE102011018852A1 - Heat-sensitive recording material with authentication feature - Google Patents

Abstract

A heat-sensitive recording material is proposed, having at least: - a web-shaped substrate, - a heat-sensitive recording layer, - at least one intermediate layer located between the substrate and the heat-sensitive recording layer, - an authenticity-proof security feature based on luminescent components, characterized in that - the luminescent components as inorganic constituents are incorporated in the at least one intermediate layer.

Description

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. In this case, 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.

For the use of recording materials, the authorized use of which is generally to be demonstrated by a specific marking of the material approved for this purpose, various solutions of authenticity-proofing security features have already been proposed in the past. Practically only two groups of security features have prevailed on the market and among consumers to this day.

On the one hand, recording materials are known which have a watermark as an authenticity-proofing security feature. A watermark is generally understood to mean a drawing in the paper, a distinction being made between genuine watermarks produced by displacement (so-called light watermarks) or by enrichment (so-called shadow watermarks) of the fiber mass, for example using a dandy cutter in the wire section of a paper machine halftone, so-called Moletten watermarks, which are produced by the embossing of the still wet paper in the press section of a paper machine, and finally spurious watermarks, the latter either by printing the finished paper outside the paper machine with a colorless lacquer or through the Embossing the finished paper to be created outside the paper machine. In addition to the undisputed effect as an authenticity-proofing security feature, genuine watermarks are also so popular because they seem to give the recording material equipped with them a particularly high-quality character.

On the other hand, recording materials are known 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.

In contrast to the control of watermarked recording materials, 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.

Basically, recording materials with fluorescent components are known as an authenticity-proofing security feature in a thoroughly complex manner.

For example, 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 81 should be incorporated into a paper or paper-like structure. Just like in the EP 1 348 575 A1 aim the so-known components, which prove to be authenticity Security feature to be used on organic substances usually in the form of fibers that are labeled with organic fluorescent dyes as well. By stretching the base substances thus marked, there are polarization effects, which are the underlying and / or characteristic components of the aforementioned publications.

In a diametrically opposite direction aims a proposal of EP 0 966 504 B1 in which a crystal-based phosphor useful as an authenticity-detecting security feature is proposed on the basis of inorganic basic substances. Indications of how the phosphors thus disclosed are to be used, however, are largely absent from this document.

A proposal of DE 198 60 093 A1 Correspondingly, a value document, such as a banknote, identity card or the like, is known with a combination of at least two authenticity-proofing security features, in which the first security feature is in the form of an inorganic luminescent substance and the second security feature is in the form of an organic luminescent substance.

In principle, the components known in this way, which usually fluoresce under special light, have proven to be authenticity-proofing security features in numerous applications, but their incorporation into coatings of heat-sensitive recording materials on the side with the heat-sensitive recording layer itself is not known on the one hand from the prior art, on the other hand also results from the great technical difficulties associated with the incorporation of such components in the said coatings of the heat-sensitive recording materials and to which the inventors were faced in many attempts underlying the invention.

Thus, it is an object of the present invention to provide the public with a heat-sensitive recording material which has at least one characteristic authenticity-detecting security feature based on luminescent components. 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.

• – ein bahnförmiges Substrat,
• – eine wärmeempfindliche Aufzeichnungsschicht,
• – mindestens eine zwischen Substrat und wärmeempfindlicher Aufzeichnungsschicht gelegene Zwischenschicht,
• – ein authentizitätsnachweisendes Sicherheitsmerkmal auf der Basis von lumineszierenden Komponenten,

dadurch gekennzeichnet, dass

• – die lumineszierenden Komponenten als anorganische Bestandteile in der mindestens einen Zwischenschicht eingebunden sind.

The object is achieved with a heat-sensitive recording material which has at least:

• A web-shaped substrate,
• A heat-sensitive recording layer,
• At least one intermediate layer located between the substrate and the heat-sensitive recording layer,
• An authenticity-proofing security feature based on luminescent components,

characterized in that

• - The luminescent components are incorporated as inorganic constituents in the at least one intermediate layer.

The invention is characterized according to the statements of the previous paragraph, characterized in that the luminescent components are incorporated as inorganic constituents in the at least one intermediate layer. In the context of the invention proposed here, it is considered preferable if 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. However, the invention is by no means limited to such fluorescent Components: Components that continue to radiate after the end of the excitation are also perfectly possible and can represent a preferred embodiment depending on the intended use.

• – mindestens ein Element umfasst, das den Übergangsmetallen und/oder den Metallen der Seltenen Erden zugerechnet wird, oder
• – eine Mehrzahl an Elementen umfasst, die den Übergangsmetallen und/oder den Metallen der Seltenen Erden zugerechnet werden.

In a preferred embodiment, the luminescent or preferably fluorescent components are formed as inorganic constituents of the pigmented intermediate layer from a substance which

• Comprises at least one element attributed to the transition metals and / or the rare earth metals, or
• A plurality of elements attributed to the transition metals and / or rare earth metals.

• – solche, wie sie in der EP 0 966 504 B1 beansprucht werden und die dort als Zusammensetzung Ln_xYb_yEr_zO_aS_b vorgeschlagen werden, wobei
• – In mindestens ein Element darstellt, das ausgewählt ist aus der Gruppe, bestehend aus Yttrium (Y), Gadolinium (Gd), Scandium (Sc) und Lanthan (La),
• – Yb = Ytterbium, Er = Erbium, O = Sauerstoff, S = Schwefel ist,
• – die Summe aus (x + y + z) = 2 ergibt,
• – die Summe aus (a + b) ≤ 3 und b < 1 ist, a ≥ 2 ist und
• – die Werte für b die Relation 0,001 ≤ b ≤ 0,9 erfüllen;
• – solche, wie sie in der EP 1 478 715 B1 beansprucht werden und die dort als Zusammensetzung (M_x, Yb_y, Tm_z)₂O₂S vorgeschlagen werden, wobei
• – M ausgewählt ist aus der Gruppe, bestehend aus Yttrium (Y), Gadolinium (Gd) und Lanthan (La),
• – Yb = Ytterbium, Tm = Thulium, O = Sauerstoff, S = Schwefel ist,
• – die Summe aus (x + y + z) = 1 ergibt und
• – die Relationen x > 0, y > 0 und 0,0025 ≤ z ≤ 0,03 erfüllt sind;

ohne dass eine solche Nennung ausschließenden Charakter haben soll.Preferred examples of such substances include

• - such as those in the EP 0 966 504 B1 are claimed and proposed there as a composition Ln _x Yb _y Er _z O _a S _b , wherein
• Represents in at least one element selected from the group consisting of yttrium (Y), gadolinium (Gd), scandium (Sc) and lanthanum (La),
• Yb = ytterbium, Er = erbium, O = oxygen, S = sulfur,
• The sum of (x + y + z) = 2,
• - the sum of (a + b) ≤ 3 and b <1, a ≥ 2 and
• - the values for b satisfy the relation 0.001 ≤ b ≤ 0.9;
• - such as those in the EP 1 478 715 B1 are claimed and proposed there as a composition (M _x , Yb _y , Tm _z ) ₂ O ₂ S, wherein
• M is selected from the group consisting of yttrium (Y), gadolinium (Gd) and lanthanum (La),
• Yb = ytterbium, Tm = thulium, O = oxygen, S = sulfur,
• - the sum of (x + y + z) = 1 gives and
• - the relations x> 0, y> 0 and 0.0025 ≤ z ≤ 0.03 are satisfied;

without this naming should have an exclusive character.

• – mindestens ein Element umfasst, das den Übergangsmetallen und/oder den Metallen der Seltenen Erden zugerechnet wird, oder
• – eine Mehrzahl an Elementen umfasst, die den Übergangsmetallen und/oder den Metallen der Seltenen Erden zugerechnet werden,

eingebunden in eine zweite Beschichtungszusammensetzung. Dabei dient diese zweite Beschichtungszusammensetzung zur Ausbildung einer Barriere bildenden Zwischenschicht, welche zwischen Substrat und wärmeempfindlicher Aufzeichnungsschicht angeordnet ist.In the context of a first preferred embodiment, the substance is the

• Comprises at least one element attributed to the transition metals and / or the rare earth metals, or
• A plurality of elements attributed to the transition metals and / or the rare earth metals,

integrated into a second coating composition. In this case, this second coating composition serves to form a barrier-forming intermediate layer, which is arranged between the substrate and the heat-sensitive recording layer.

• – mindestens ein Element umfasst, das den Übergangsmetallen und/oder den Metallen der Seltenen Erden zugerechnet wird, oder
• – eine Mehrzahl an Elementen umfasst, die den Übergangsmetallen und/oder den Metallen der Seltenen Erden zugerechnet werden,

zu mindestens 0,5 g – bezogen auf 1 kg aller Bestandteile der zweiten Beschichtungszusammensetzung – in der zweiten Beschichtungszusammensetzung zur Ausbildung einer Barriere bildenden Zwischenschicht eingebunden.In the context of a particularly preferred embodiment of this first preferred embodiment, the substance is the

• Comprises at least one element attributed to the transition metals and / or the rare earth metals, or
• A plurality of elements attributed to the transition metals and / or the rare earth metals,

to at least 0.5 g - based on 1 kg of all components of the second coating composition - incorporated in the second coating composition to form a barrier-forming intermediate layer.

It is considered preferable within this first preferred embodiment if the barrier-forming interlayer contains ethylene-vinyl alcohol copolymer (EVOH).

The reason for the preferred embodiment of the barrier layer disposed between the substrate and the heat-sensitive recording layer is to protect the heat-sensitive recording layer sustainably against 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 in the decisive way also in larger quantities in the Substrate may be included 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, very preferably at least 98% by weight, based in each case 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 furthermore be, for example, defoamers and / or agents for stabilizing the color curtain in the case of a possible application of the second coating composition by means of curtain coats or slide coaters.

• – mindestens ein Element umfasst, das den Übergangsmetallen und/oder den Metallen der Seltenen Erden zugerechnet wird, oder
• – eine Mehrzahl an Elementen umfasst, die den Übergangsmetallen und/oder den Metallen der Seltenen Erden zugerechnet werden,

eingebunden in eine dritte Beschichtungszusammensetzung. Dabei dient diese dritte Beschichtungszusammensetzung zur Ausbildung einer pigmentierten Zwischenschicht, welche zwischen Substrat und wärmeempfindlicher Aufzeichnungsschicht angeordnet ist.In the context of a, as an alternative to the first preferred embodiment variant applicable second preferred embodiment, the substance is the

• Comprises at least one element attributed to the transition metals and / or the rare earth metals, or
• A plurality of elements attributed to the transition metals and / or the rare earth metals,

integrated into a third coating composition. In this case, this third coating composition serves to form a pigmented intermediate layer, which is arranged between the substrate and the heat-sensitive recording layer.

• – mindestens ein Element umfasst, das den Übergangsmetallen und/oder den Metallen der Seltenen Erden zugerechnet wird, oder
• – eine Mehrzahl an Elementen umfasst, die den Übergangsmetallen und/oder den Metallen der Seltenen Erden zugerechnet werden,

zu mindestens 0,5 g – bezogen auf 1 kg aller Bestandteile der dritten Beschichtungszusammensetzung – in der dritten Beschichtungszusammensetzung zur Ausbildung einer pigmentierten Zwischenschicht eingebunden.In the context of a particularly preferred embodiment of this second preferred embodiment, the substance is the

• Comprises at least one element attributed to the transition metals and / or the rare earth metals, or
• A plurality of elements attributed to the transition metals and / or the rare earth metals,

to at least 0.5 g - based on 1 kg of all components of the third coating composition - incorporated in the third coating composition to form a pigmented intermediate layer.

• – mindestens ein organisches und/oder ein anorganisches Pigment,
• – ein Bindemittel, und
• – das authentizitätsnachweisende Sicherheitsmerkmal auf der Basis von lumineszierenden Komponenten,

wobei die lumineszierenden Komponenten als anorganische Bestandteile in der pigmentierten Zwischenschicht eingebunden sind.The pigmented intermediate layer formed from the third coating composition within this second preferred embodiment then preferably comprises

• At least one organic and / or one inorganic pigment,
• A binder, and
• The authenticity-proofing security feature based on luminescent components,

wherein the luminescent components are incorporated as inorganic constituents in the pigmented intermediate layer.

In a preferred embodiment within this second preferred embodiment variant, 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 pigment, 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 .-% 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. 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.

In addition to the inorganic and optionally also organic pigments, 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. The use of 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.

It has also been recognized that, in particular, a ratio based on the weight% in the third coating composition
Fabric _{according to paragraphs [0014] to [0016] and from [0022]} : _total pigment
in a range of 0.5 g: 1 kg to 50 g: 1 kg.

• – dass die Barriere bildende Zwischenschicht dem Substrat zugewandt ist und
• – dass die pigmentierte Zwischenschicht der wärmeempfindlichen Aufzeichnungsschicht zugewandt ist, und wobei der Stoff, der
• – mindestens ein Element umfasst, das den Übergangsmetallen und/oder den Metallen der Seltenen Erden zugerechnet wird, oder
• – eine Mehrzahl an Elementen umfasst, die den Übergangsmetallen und/oder den Metallen der Seltenen Erden zugerechnet werden,

in mindestens eine oder beide Zwischenschichten derart eingebunden ist wie offenbart in den vorherigen Absätzen [0017] bis [0029]. Entsprechend kann dann eine Zwischenschicht, ausgesucht aus der Barriere bildende Zwischenschicht und der pigmentierten Zwischenschicht so aufgebaut sein, wie offenbart in den vorherigen Absätzen [0017] bis [0029], jedoch ohne die lumineszierenden bzw. fluoreszierenden Komponenten.In a third preferred embodiment, the proposed heat-sensitive recording material between the web-shaped substrate and the heat-sensitive recording layer both a barrier-forming intermediate layer as well as a pigmented intermediate layer, wherein the order of these two intermediate layers is set such

• - That the barrier-forming intermediate layer faces the substrate and
• That the pigmented intermediate layer faces the heat-sensitive recording layer, and wherein the substance, the
• Comprises at least one element attributed to the transition metals and / or the rare earth metals, or
• A plurality of elements attributed to the transition metals and / or the rare earth metals,

in at least one or both intermediate layers is incorporated as disclosed in the previous paragraphs [0017] to [0029]. Accordingly, an intermediate layer selected from the barrier-forming intermediate layer and the pigmented intermediate layer may then be constructed as disclosed in the previous paragraphs [0017] to [0029] but without the luminescent or fluorescent components.

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. Very particular preference is given to 3-dibutylamino-6-methyl-7-anilinofluoran - also known as ODB-2.

It is also possible that the first coating composition has more than one dye precursor, each selected from the dye precursors listed in the above paragraph.

• – 2,2 bis (4-hydroxyphenyl)-propan;
• – 4-[(4-(1-methylethoxy)phenyl)sulfonyl]phenol;
• – 4,4'-Dihydroxydiphenylsulfon;
• – N-(p-toluensulphonyl)-N'-(3-p-toluensulphonyl-oxy-phenyl)-harnstoff, auch bekannt als Pergafast^® 201 der Firma CIBA Speciality Chemicals Inc. und darstellbar gemäß der nachfolgenden Formel (1), wobei in manchen Darstellungen die CH₃-Gruppen auch weggelassen werden;

Formel 1:

• – 2,4'-dihydroxy-diphenylsulfon;
• – N-(2-hydroxyphenyl)-2-[(4-hydroxyphenyl)thio]acetamid.

The thermosensitive recording layer formed from the first coating composition contains, as a color acceptor, at least one substance selected from the list, comprising:

• 2,2 bis (4-hydroxyphenyl) -propane;
• - 4 - [(4- (1-methylethoxy) phenyl) sulfonyl] phenol;
• 4,4'-dihydroxydiphenylsulfone;
• - N- (p-toluensulphonyl) -N '- (3-p-toluensulphonyl-oxy-phenyl) urea, also known as Pergafast ^® 201 from Ciba Specialty Chemicals Inc. and represented by the following Formula (1), wherein in some representations the CH ₃ groups are also omitted;

Formula 1:

• 2,4'-dihydroxy-diphenylsulfone;
• N- (2-hydroxyphenyl) -2 - [(4-hydroxyphenyl) thio] acetamide.

Suitable binders for incorporation into the heat-sensitive recording layer are, for example, water-soluble binders such as starch, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, esp. Polyvinyl alcohols, modified polyvinyl alcohols, sodium polyacrylates, acrylamide-acrylate copolymers, acrylamide-acrylate-methacrylate terpolymers, esp. 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 are also suitable as binders for incorporation into the heat-sensitive recording layer. For the purposes of the present invention are 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.

In order to prevent sticking to a thermal head and to prevent excessive wear of the thermal head, the first coating composition for forming the heat-sensitive 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. With respect to the kaolin, in the laboratory and experimental production work on which the invention is based, 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. For the purposes of the present invention, in particular 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.

It is a particularly preferable embodiment when the heat-sensitive recording material proposed here has a protective layer covering the heat-sensitive recording layer. Such a protective layer is 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.

In addition to 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 - containing ethylene-vinyl alcohol copolymer, very good results could be achieved with a protective layer containing at least 60 wt .-%, particularly preferably at least 85 wt .-% as a binder. Diacetone-modified polyvinyl alcohol, wherein the two values to the weight. % refer to the total amount of binder 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 so very particularly preferred may comprise, in addition to the diacetone-modified polyvinyl alcohol in a first possible embodiment, 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. In a second possible embodiment, the protective layer of the proposed thermosensitive recording material has as binder exclusively diacetone-modified polyvinyl alcohol. In particular, when diacetone-modified polyvinyl alcohol is the sole binder in the protective layer covering the heat-sensitive recording layer, it is most preferable that 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.

It is preferable if, within the protective layer, 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.

Particularly good results have been achieved if the protective layer additionally contains an inorganic pigment. It is particularly recommended that 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. In this case, in particular, a ratio of pigment and here very particularly preferably non-calcined kaolin to the diacetone-modified polyvinyl alcohol in a range of 1: 1.5 to 1: 4.5 set, the ratio here based on the respective wt .-% of Pigment and polyvinyl alcohol in the protective layer.

• – als nicht oberflächenbehandeltes, idealerweise in der Masse geleimtes Papier,
• – als ungeleimtes, aber zumindest einseitig präpariertes Papier,
• – als zumindest einseitig mit einer Polyolefinbeschichtung versehenes Papier

zum Einsatz kommt. Dabei kann dieses Papier – gerade bei seiner vorgesehenen Verwendung als Fahrscheinmaterial bei Bussen und Bahnen genauso wie im Flugverkehr – insbesondere ein Wasserzeichen als ein zweites authentizitätsnachweisendes Sicherheitsmerkmal aufweisen, wobei unterschieden wird zwischen

• – echten Wasserzeichen, die durch Verdrängung (sogenannte Licht-Wasserzeichen) oder durch Anreicherung (sogenannte Schatten-Wasserzeichen) der Fasermasse beispielsweise unter Verwendung eines Egoutteurs in der Siebpartie einer Papiermaschine hergestellt werden,
• – halbechten, sogenannten Moletten-Wasserzeichen, die durch die Prägung des noch nassen Papiers in der Pressenpartie einer Papiermaschine erzeugt werden, und schließlich
• – unechten Wasserzeichen, wobei letztere entweder durch das Bedrucken des fertig gestellten Papiers außerhalb der Papiermaschine mit einem farblosen Lack oder durch das Prägen des fertig gestellten Papiers außerhalb der Papiermaschine erstellt werden.

As a web-shaped substrate paper is preferred as that particular

• As non-surface treated, ideally sized paper,
• - as unsized but at least unilaterally prepared paper,
• - As at least one side provided with a polyolefin coating paper

is used. In this case, this paper - especially in its intended use as a ticket material on buses and trains as well as in air traffic - in particular have a watermark as a second authentizitätsnachweisendes security feature, being distinguished between

• Genuine watermarks produced by displacement (so-called light watermarks) or by enrichment (so-called shadow watermarks) of the fiber mass, for example using a dandy cutter in the wire section of a paper machine,
• - half-right, so-called Moletten watermarks, which are produced by the embossing of the still wet paper in the press section of a paper machine, and finally
• - Spurious watermark, the latter being created either by printing the finished paper outside the paper machine with a colorless paint or by embossing the finished paper outside the paper machine.

For the purposes of the present invention, all the above-mentioned security features are considered to be preferred, the inclusion of a real watermark moreover than being particularly preferred.

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.

• – Ausbilden eines bahnförmigen Substrates;
• – Vorbereiten einer dritten Beschichtungszusammensetzung, wobei diese dritte Beschichtungszusammensetzung mindestens umfasst:
• – mindestens ein organisches und/oder ein anorganisches Pigment,
• – ein Bindemittel,
• – ein authentizitätsnachweisendes Sicherheitsmerkmal auf der Basis von lumineszierenden Komponenten, wobei die lumineszierenden Komponenten als anorganische Bestandteile in der pigmentierten Zwischenschicht eingebunden werden;
• – Aufbringen der vorbereiteten dritten Beschichtungszusammensetzung zur Ausbildung einer pigmentierten Zwischenschicht auf dem bahnförmigen Substrat;
• – Trocknen der dritten Beschichtungszusammensetzung;
• – Vorbereiten einer ersten Beschichtungszusammensetzung, wobei diese erste Beschichtungszusammensetzung mindestens umfasst:
• – mindestens einen Farbstoffvorläufer,
• – mindestens einen Farbakzeptor, wobei Farbstoffvorläufer und Farbakzeptor unter Einwirkung von Wärme farbbildend miteinander reagieren;
• – Aufbringen der vorbereiteten ersten Beschichtungszusammensetzung zur Ausbildung einer wärmeempfindlichen Aufzeichnungsschicht auf der pigmentierten Zwischenschicht;
• – Trocknen der ersten Beschichtungszusammensetzung;
• – Aufrollen des bahnförmigen Substrates mit der ausgebildeten pigmentierten Zwischenschicht mit der ausgebildeten wärmeempfindlichen Aufzeichnungsschicht.

For producing a heat-sensitive recording material in its second preferred embodiment according to the preceding paragraphs [0022] to [0029], such a method comprises at least the following method steps:

• - Forming a web-shaped substrate;
• Preparing a third coating composition, said third coating composition comprising at least
• At least one organic and / or one inorganic pigment,
• A binder,
• An authenticity-detecting security feature based on luminescent components, wherein the luminescent components are incorporated as inorganic constituents in the pigmented intermediate layer;
• Applying the prepared third coating composition to form a pigmented intermediate layer on the web-shaped substrate;
• - drying the third coating composition;
• Preparing a first coating composition, said first coating composition comprising at least
• At least one dye precursor,
• - At least one color acceptor, wherein dye precursor and color acceptor under the action of heat color-forming react with each other;
• Applying the prepared first coating composition to form a heat-sensitive recording layer on the pigmented intermediate layer;
• - drying the first coating composition;
• - Rolling of the web-shaped substrate with the formed pigmented intermediate layer with the formed heat-sensitive recording layer.

• – seiner dritten bevorzugten Ausführungsvariante gemäß des Absatzes [0030] in Verbindung mit den Absätzen [0017] bis [0029]
• – mit einer dabei besonders bevorzugten Schutzschicht gemäß der Absätze [0037] bis [0042]

For producing a heat-sensitive recording material in a possible embodiment

• - its third preferred embodiment according to paragraph [0030] in conjunction with paragraphs [0017] to [0029]
• With a particularly preferred protective layer according to paragraphs [0037] to [0042]

• – Ausbilden eines bahnförmigen Substrates;
• – Vorbereiten einer zweiten Beschichtungszusammensetzung, wobei diese zweite Beschichtungszusammensetzung mindestens umfasst:
• – Ethylen-Vinyl-Alkohol-Copolymer,
• – optional Entschäumer,
• – optional Mittel zur Stabilisierung eines Farbvorhangs;
• – Aufbringen der vorbereiteten zweiten Beschichtungszusammensetzung zur Ausbildung einer Barriere bildende Zwischenschicht auf dem bahnförmigen Substrat;
• – Trocknen der zweiten Beschichtungszusammensetzung;
• – Vorbereiten einer dritten Beschichtungszusammensetzung, wobei diese dritte Beschichtungszusammensetzung mindestens umfasst:
• – mindestens ein organisches und/oder ein anorganisches Pigment,
• – ein Bindemittel,
• – ein authentizitätsnachweisendes Sicherheitsmerkmal auf der Basis von lumineszierenden Komponenten, wobei die lumineszierenden Komponenten als anorganische Bestandteile in der pigmentierten Zwischenschicht eingebunden werden;
• – Aufbringen der vorbereiteten dritten Beschichtungszusammensetzung zur Ausbildung einer pigmentierten Zwischenschicht auf der Barriere bildende Zwischenschicht;
• – Trocknen der dritten Beschichtungszusammensetzung,
• – Vorbereiten einer ersten Beschichtungszusammensetzung, wobei diese erste Beschichtungszusammensetzung mindestens umfasst:
• – mindestens einen Farbstoffvorläufer,
• – mindestens einen Farbakzeptor, wobei Farbstoffvorläufer und Farbakzeptor unter Einwirkung von Wärme farbbildend miteinander reagieren;
• – Aufbringen der vorbereiteten ersten Beschichtungszusammensetzung zur Ausbildung einer wärmeempfindlichen Aufzeichnungsschicht auf der pigmentierten Zwischenschicht;
• – Trocknen der ersten Beschichtungszusammensetzung;
• – Vorbereiten einer vierten Beschichtungszusammensetzung, wobei diese vierte Beschichtungszusammensetzung mindestens umfasst:
• – Diaceton-modifizierten Polyvinylalkohol,
• – Vernetzungshilfsmittel,
• – optional anorganisches Pigment;
• – Aufbringen der vorbereiteten vierten Beschichtungszusammensetzung zur Ausbildung einer die wärmeempfindliche Aufzeichnungsschicht abdeckenden Schutzschicht;
• – Trocknen der vierten Beschichtungszusammensetzung;
• – Aufrollen des bahnförmigen Substrates mit der ausgebildeten Barriere bildenden Zwischenschicht, mit der ausgebildeten pigmentierten Zwischenschicht, mit der ausgebildeten wärmeempfindlichen Aufzeichnungsschicht und mit der ausgebildeten, die wärmeempfindliche Aufzeichnungsschicht abdeckenden Schutzschicht.

In this case, such a method preferably comprises at least the following method steps:

• - Forming a web-shaped substrate;
• Preparing a second coating composition, said second coating composition comprising at least
• Ethylene-vinyl alcohol copolymer,
• - optional defoamer,
• - optional means for stabilizing a color curtain;
• - applying the prepared second coating composition to form a barrier-forming intermediate layer on the web-shaped substrate;
• - drying the second coating composition;
• Preparing a third coating composition, said third coating composition comprising at least
• At least one organic and / or one inorganic pigment,
• A binder,
• An authenticity-detecting security feature based on luminescent components, wherein the luminescent components are incorporated as inorganic constituents in the pigmented intermediate layer;
• Applying the prepared third coating composition to form a pigmented intermediate layer on the barrier-forming intermediate layer;
• Drying the third coating composition,
• Preparing a first coating composition, said first coating composition comprising at least
• At least one dye precursor,
• - At least one color acceptor, wherein dye precursor and color acceptor under the action of heat color-forming react with each other;
• Applying the prepared first coating composition to form a heat-sensitive recording layer on the pigmented intermediate layer;
• - drying the first coating composition;
• Preparing a fourth coating composition, said fourth coating composition comprising at least
• - Diacetone-modified polyvinyl alcohol,
• - crosslinking aids,
• - optional inorganic pigment;
• - applying the prepared fourth coating composition to form a protective layer covering the heat-sensitive recording layer;
• - drying the fourth coating composition;
• Rolling up the web-shaped substrate with the barrier layer forming intermediate layer, with the formed pigmented intermediate layer, with the formed thermosensitive recording layer and with the formed, the heat-sensitive recording layer covering protective layer.

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. In particular, but not limitation, when such 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 .

Preferably, 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. Especially in a method using one of these mentioned coating method, 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 is 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. For the basis weight of the pigmented intermediate layer, a preferred range between 5 and 20 g / m ² and even better between 7 and 12 g / m ^{2 has} proven.

After a possible smoothing of the optionally produced by Egoutteur, genuine watermarked paper web as a web-shaped substrate, this can be rolled up at the end of the paper machine as a semi-finished product on a spool.

• – ausgesucht aus der Barriere bildenden Zwischenschicht und der pigmentierten Zwischenschicht –

und darauf die vorbereitete erste Beschichtungszusammensetzung zur Ausbildung einer wärmeempfindlichen Aufzeichnungsschicht aufgebracht. Bevorzugt wird die erste Beschichtungszusammensetzung dabei mittels eines Streichverfahrens aufgebracht, ausgesucht aus der Liste, umfassend: Rollrakelstreichwerk, Messerstreichwerk, Vorhangbeschichter oder Luftbürste. Die zur Ausbildung der Aufzeichnungsschicht genutzte erste Beschichtungszusammensetzung ist dabei bevorzugt wässerig. Die anschließende Trocknung der ersten Beschichtungszusammensetzung geschieht üblicherweise durch ein Verfahren, bei dem Wärme zugeführt wird, wie es durch Heißluft-Schwebetrockner oder auch Kontakttrockner geschieht. Bewährt ist auch eine Kombination aus den aufgeführten Trockenverfahren. Die flächenbezogene Masse der wärmeempfindlichen Aufzeichnungsschicht liegt bevorzugt zwischen 2 und 6 g/m² und noch besser zwischen 2,2 und 4,8 g/m².After an optionally necessary upstream unrolling of the web-shaped substrate as a semi-finished product from a spool, 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 .

As 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 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, as proposed here, 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. Furthermore, 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.

Finally, 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.

The present invention, 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 details given in the description and claims relating to basis weight,% by weight (% by weight) and parts by weight (parts by weight) are based on the "atro" weight in each case, ie. H. absolutely dry parts by weight. In the comments on the organic pigments of the pigment-containing intermediate layer, the relevant figures are calculated from the "lutro" weight, d. H. air-dry parts by weight, minus the proportion by weight of water around and inside the pigments in their form of delivery.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1233106 B1 [0008]
• EP 144652881 [0008]
• EP 1348575 A1 [0008]
• EP 0966504 B1 [0009, 0016]
• DE 19860093 A1 [0010]
• EP 1478715 B1 [0016]

Claims (19)

Heat-sensitive recording material, comprising at least: a web-shaped substrate, a heat-sensitive recording layer, at least one interlayer between substrate and heat-sensitive recording layer, an authenticity-detecting security feature based on luminescent components, characterized in that the luminescent components are used as inorganic constituents in the at least one intermediate layer are integrated. Heat-sensitive recording material according to claim 1, characterized in that the inorganic constituents are fluorescent components. Heat-sensitive recording material according to one of the claims 1 or 2, characterized in that the inorganic constituents are formed from a substance which comprises at least one element which is attributed to the transition metals and / or the metals of the rare earths. Heat-sensitive recording material according to one of claims 1 to 3, characterized in that the inorganic constituents are formed from a substance which comprises a plurality of elements which are attributed to the transition metals and / or the metals of the rare earths. Heat-sensitive recording material according to one of the claims 3 or 4, characterized in that the substance which At least one element attributed to the transition metals and / or the metals of the rare earths, or A plurality of elements attributed to the transition metals and / or the rare earth metals, to at least 0.5 g - based on 1 kg of all components of a second coating composition - is incorporated in the second coating composition to form a barrier-forming intermediate layer. Heat-sensitive recording material according to one of the claims 3 or 4, characterized in that the substance which At least one element attributed to the transition metals and / or the metals of the rare earths, or A plurality of elements attributed to the transition metals and / or the rare earth metals, to at least 0.5 g - based on 1 kg of all components of a third coating composition - is incorporated in the third coating composition to form a pigmented intermediate layer. Heat-sensitive recording material according to claim 6, characterized in that the pigmented intermediate layer formed from the third coating composition contains at least one organic pigment and at least one inorganic pigment. Heat-sensitive recording material according to claim 7, characterized in that 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 in particular boehmite here. Heat-sensitive recording material according to claim 5, characterized in that the barrier-forming intermediate layer formed from the second coating composition comprises at least 90% by weight, based on the total weight of the barrier-forming intermediate layer, of an ethylene-vinyl alcohol copolymer (EVOH). Heat-sensitive recording material according to one of the claims 1 to 9, characterized in that the heat-sensitive recording layer comprises at least one organic dye precursor and having at least one organic dye acceptor, wherein dye precursor and dye acceptor react color-forming with each other under the action of heat. Heat-sensitive recording material according to one of the claims 1 to 10, characterized in that the heat-sensitive recording layer contains as color acceptor at least one substance selected from the list, comprising: 2,2 bis (4-hydroxyphenyl) -propane, 4-[(4- (1-methylethoxy) phenyl) sulfonyl] phenol, 4,4'-dihydroxydiphenyl sulfone, N- (p-toluenesulphonyl) -N '- (3-p-toluenesulphonyl-oxy-phenyl) -urea, 2,4'-dihydroxydiphenyl sulfone, N- (2-hydroxyphenyl) -2 - [(4-hydroxyphenyl) thio] acetamide. A heat-sensitive recording material according to any one of claims 1 and 11, characterized in that the thermosensitive recording layer as dye precursor comprises at least one substance 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. A heat-sensitive recording material according to any one of claims 1 to 12, characterized in that the heat-sensitive recording layer contains as binder a substance selected from the list comprising: polyvinyl alcohol, ethylene-vinyl alcohol copolymer or a combination of polyvinyl alcohol and ethylene-vinyl alcohol copolymer. A heat-sensitive recording material according to any one of claims 1 to 13, characterized in that the heat-sensitive recording material has a protective layer covering the heat-sensitive recording layer. Heat-sensitive recording material according to claim 14, characterized in that the protective layer comprises, as binder, at least 60% by weight, based on the total amount of binder in the protective layer, of diacetone-modified polyvinyl alcohol. Process for producing a heat-sensitive recording material according to one of claims 6 to 8, comprising at least the following process steps: - Forming a web-shaped substrate; Preparing a third coating composition, said third coating composition comprising at least At least one organic and / or one inorganic pigment, A binder, An authenticity-proofing security feature based on luminescent components, wherein the luminescent components are incorporated as inorganic constituents in the pigmented intermediate layer; Applying the prepared third coating composition to form a pigmented intermediate layer on the web-shaped substrate; - drying the third coating composition; Preparing a first coating composition, said first coating composition comprising at least At least one dye precursor, At least one color acceptor, wherein dye precursor and color acceptor react with each other under the action of heat in a color-forming manner; Applying the prepared first coating composition to form a heat-sensitive recording layer on the pigmented intermediate layer; - drying the first coating composition; - Rolling of the web-shaped substrate with the formed pigmented intermediate layer with the formed heat-sensitive recording layer. A process for producing a heat-sensitive recording material according to claim 16, characterized in that the first coating composition by means of a coating process selected from the list, comprising: roller blade coater, knife coater, curtain coater and air brush. A process for producing a heat-sensitive recording material according to claims 16 and 17, characterized in that the third coating composition is applied by means of a leveling coating process selected from the list comprising: roller coater, doctor blade or doctor blade coater. Process for the preparation of a thermosensitive recording material according to any one of claims 16 to 18, characterized in that the web-shaped substrate is produced by means of a paper machine having a dandy who presses a real watermark into the still wet substrate.