EP2505374B1 - Heat-sensitive recording material, method for its manufacture and application - Google Patents

Description

• ■ ein oder mehrere Farbstoffvorläufer,
• ■ als Entwickler N-(p-toluensulphonyl)-N'-3-(p-toluensulphonyl-Oxy-phenyl)-harnstoff gemäß der folgenden Formel (1):
  
• ■ ein Bindemittel,
• ■ Pigment, ausgesucht aus der Liste, umfassend: Kaolin, Silizium(di)oxid, Bentonit, Talkum, Kalziumkarbonat sowie Aluminiumoxid und hier besonders Böhmit.

The present invention relates to a recording material having a web-shaped substrate and a heat-sensitive recording layer as an outer-outer layer, wherein the heat-sensitive recording layer has at least:

• ■ one or more dye precursors,
• ■ as a developer N- (p-toluenesulphonyl) -N'-3- (p-toluenesulphonyl-oxy-phenyl) -urea according to the following formula (1):
  
• ■ a binder,
• ■ pigment selected from the list comprising: kaolin, silicon (di) oxide, bentonite, talc, calcium carbonate and alumina, and here especially boehmite.

The invention further relates to the use of the recording material according to the invention in particular as a material for the formation of tickets and a method for its production.

Heat-sensitive recording materials of the type described in particular with paper as a web-shaped substrate are known since the early years of chemically reactive recording materials and enjoy a constantly growing popularity, which is due, inter alia, that their use is particularly associated with a ticket for the ticket issuing with great advantages , Because the color-forming components are stuck in the recording material itself in the heat-sensitive recording method, the toner and ink-cartridge-free printers, which in their function no longer need to be controlled by anyone and thus largely maintenance-free, can be set up in large numbers. So this innovative technology has become particularly important in public transport, on buses and trains as well as in air traffic, but as it were also enforced at stadium and museum funds and at parking detectors.

A not necessarily generic recording material having a web-shaped substrate and a heat-sensitive recording layer as an outwardly terminating outer layer containing as developer N- (p-toluenesulphonyl) -N'-3- (p-toluenesulphonyl-oxy-phenyl) -urea according to formula ( 1) contains, for example, from the EP 2 033 799 A1 known. The subject matter of this disclosure is the combination of N- (p-toluenesulphonyl) -N'-3- (p-toluenesulphonyl-oxy-phenyl) -urea essential to the invention with a urea-urethane compound according to the following formula (2):

The cited document, however, are no suggestions for the use of a pigment combination of two pigments, especially not to refer to a certain pigment mixing ratio.

A not necessarily generic recording material with a web-shaped substrate and a heat-sensitive recording layer, which can still be covered here by means of a protective layer, is further from the EP 2 033 801 B1 known. Here, the published document provides the invention essential combination of N- (p-toluenesulphonyl) -N'-3- (p-toluenesulphonyl-oxy-phenyl) urea with 2- (2H-benzotriazol-2-yl) -p-cresol according to the following formula (3) as a sensitizer.

Again, the above document no suggestions for the use of a pigment combination of two pigments, certainly not to be taken for a given pigment mixing ratio.

Subject of the EP 1 208 994 A1 is a thermosensitive recording material having a leuco base dye precursor, N- (p-toluenesulphonyl) -N'-3- (p-toluenesulphonyl-oxy-phenyl) urea as a developer and at least one pigment selected from the list comprising aluminum hydroxide, amorphous Silica, kaolin and talc in the heat-sensitive recording layer. As a possible pigment in the heat-sensitive recording layer, calcium carbonate is also disclosed. By way of example, heat-sensitive recording layers are disclosed without pigment (!) And with exactly one pigment selected from the list comprising aluminum hydroxide, amorphous silica, kaolin, talc and magnesium carbonate. It is significant that also this document no suggestions for the use of a pigment combination of two pigments, certainly not to be taken for a given pigment mixing ratio.

The present invention has, starting from the previously acknowledged writings the task of providing a suitable in particular as ticket and / or ticket heat-sensitive recording material available, which must be produced due to high sales volumes in a fiercely competitive market at low production costs and therefore a simple Construction has to dispose. In particular, the new recording material should require no additional protective layer to cover the heat-sensitive recording layer, because such a protective layer is too costly both in terms of the necessary raw materials as well as in terms of the necessary machinery and process energies. At the same time, however, the new recording material should have excellent resistance to ethanol solutions, water, plasticizers, and ideally also to glycol-containing liquid mists.

Such resistances are required for ticketing heat-sensitive recording materials, on an ever-increasing scale, because the tickets often come in contact with wet or misty moisture on one side and plasticizers as components of plug-in covers on the other side.

It is essential that the novel recording material also has excellent running performance within the thermal-induced-image-type thermal printers, including low abrasiveness of the recording material to the thermal head, and particularly, keeping away the thermal head melt generated in the thermosensitive recording layer during the image formation. The point of excellent running behavior on thermal printers is of such great importance because the new recording material should not have any protective layer with the help of which the running behavior on thermal printers can be optimized in a particularly targeted manner. Because of the task proper alignment of the new recording material to its suitability as a ticket and / or ticket, it is particularly of interest that the barcode readability must be good. Important for the functionality of the paper is also an excellent stampability. A good Bestempelbarkeit is considered given when stamped lettering after about 10 seconds, neither dry nor wet can be completely wiped away.

• ■ ein oder mehrere Farbstoffvorläufer,
• ■ als Entwickler N-(p-toluensulphonyl)-N'-3-(p-toluensulphonyl-Oxy-phenyl)-harnstoff gemäß der folgenden Formel (1):
  
• ■ ein Bindemittel,
• ■ Pigment, ausgesucht aus der Liste, umfassend: Kaolin, Silizium(di)oxid, Bentonit, Talkum, Kalziumkarbonat sowie Aluminiumoxid und hier besonders Böhmit,

wobei das hier vorgeschlagene Aufzeichnungsmaterial dadurch gekennzeichnet wird, dass die erste Beschichtungszusammensetzung als Pigment mindestens eine Pigmentkombination enthält, wobei die Pigmentkombination ausgesucht ist aus der Liste, umfassend:

• Kalziumkarbonat und Silizium(di)oxid,
• Aluminium(hydr)oxid und Silizium(di)oxid,
• Kalziumkarbonat und Aluminium(hydr)oxid.

The object is achieved with a recording material having a web-shaped substrate and a heat-sensitive recording layer as an outer, outer layer, wherein the heat-sensitive recording layer is formed from a first coating composition, comprising at least

• ■ one or more dye precursors,
• ■ as a developer N- (p-toluenesulphonyl) -N'-3- (p-toluenesulphonyl-oxy-phenyl) -urea according to the following formula (1):
  
• ■ a binder,
• ■ pigment selected from the list comprising: kaolin, silicon (di) oxide, bentonite, talc, calcium carbonate and alumina, and here especially boehmite,

wherein the recording material proposed here is characterized in that the first coating composition as pigment at least one pigment combination containing the pigment combination selected from the list, comprising:

• Calcium carbonate and silicon (di) oxide,
• Aluminum (hydr) oxide and silicon (di) oxide,
• Calcium carbonate and aluminum (hydr) oxide.

N- (p-toluensulphonyl) -N'-3- (p-toluensulphonyl-oxy-phenyl) -urea according to the above formula (1) is known as Pergafast ^® 201 from Ciba Specialty Chemicals Inc., and in some illustrations, the CH ₃ groups also be omitted.

The thermosensitive recording material preferably has, as a dye precursor in the first coating composition, 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 possible that the first coating composition has more than one dye precursor, each selected from the dye precursors listed in the above paragraph.

In addition to or as an alternative to the substances mentioned in the previous paragraph as dye precursors, the first coating composition may contain one or more of the following near infrared absorbing compounds:

3,6-Bis (dimethylamino) fluorene-9-spiro-3 '- (6'-dimethylaminophthalide), 3-diethylamino-6-dimethylaminofluorene-9-spiro-3' - (6'-dimethylaminophthalide), 3.6- Bis (diethylamino) -fluorene-9-spiro-3 '- (6'-dimethylaminophthalide), 3-dibutylamino-6-dimethylaminofluorene-9-spiro-3' - (6'-dimethylaminophthalide), 3-dibutylamino-6-diethylaminofluorene -9-spiro-3 '- (6'-dimethylaminophthalide), 3,6-bis (dimethylamino) fluorene-9-spiro-3' - (6'-diethylamino-phthalide), 3-diethylamino-6-dimethylaminofluorene-9 -spiro-3 '- (6'-diethylaminophthalide), 3-dibutylamino-6-dimethylaminofluorene-9-spiro-3' - (6'-diethylaminophthalide), 3,6-bis (di-ethylamino) fluorene-9- spiro-3 '- (6'-diethylaminophthalide), 3,6-bis (dimethylamino) -fluorene-9-spiro-3 '- (6'-dibutylaminophthalide), 3-dibutylamino-6-diethylaminofluorene-9-spiro-3' - (6'-diethylaminophthalide), 3- Diethylamino-6-dimethylaminofluorene-9-spiro-3 '- (6'-dibutylaminophthalide), 3,3-bis [2- (4-dimethylaminophenyl) -2- (4-methoxyphenyl) -ethenyl] -4,5,6,7 -tetrachlorophthalid.

• Kalziumkarbonat und Silizium(di)oxid,
• Aluminium(hydr)oxid und Silizium(di)oxid,
• Kalziumkarbonat und Aluminium(hydr)oxid.

Hinsichtlich des Kaolins erkannten die Erfinder in den dieser Erfindung zugrundeliegenden Labor- und Versuchsproduktionsarbeiten, dass kalziniertes Kaolin aufgrund seiner großen Abrasivität zur Einbindung in die erste Beschichtungszusammensetzung zur Ausbildung der wärmeempfindlichen Aufzeichnungsschicht abzulehnen ist.According to the invention, the first coating composition for forming the heat-sensitive recording layer comprises as pigment at least one pigment combination, the pigment combination being selected from the list, comprising:

• Calcium carbonate and silicon (di) oxide,
• Aluminum (hydr) oxide and silicon (di) oxide,
• Calcium carbonate and aluminum (hydr) oxide.

With regard to kaolin, in the laboratory and experimental production work underlying this invention, the inventors recognized that calcined kaolin should be rejected for inclusion in the first coating composition for forming the thermosensitive recording layer because of its high abrasiveness.

In a first embodiment, the first coating composition contains at least calcium carbonate and silicon (di) oxide as the at least two pigments. Most preferably, the first coating composition contains only calcium carbonate and silicon (di) oxide as the at least two pigments.

In numerous series of experiments, it has been found that the mixing ratio of calcium carbonate and silicon (di) oxide is particularly advantageous in terms of the underlying tasks, if this ratio of calcium carbonate to silicon (di) oxide in a ratio of 1% by weight in the first coating composition Range from 10: 1 to 1: 1, more preferably from 2: 1 to 1.2: 1.

• ■ Aluminium(hydr)oxid und Silizium(di)oxid enthält,
• ■ ganz besonders bevorzugt Aluminium(hydr)oxid und Silizium(di)oxid ausschließlich aufweist.

A second embodiment alternative to the first embodiment is obtained when the first coating composition is the at least two pigments

• Contains aluminum (hydr) oxide and silicon (di) oxide,
• Most preferably aluminum (hydr) oxide and silicon (di) oxide exclusively.

In this case, the ratio of aluminum (hydr) oxide to silicon (di) oxide based on% by weight in the first coating composition is preferably in a range from 25: 1 to 5: 1.

• ■ Kalziumkarbonat und Aluminium(hydr)oxid enthält,
• ■ ganz besonders bevorzugt Kalziumkarbonat und Aluminium(hydr)oxid ausschließlich aufweist.

Dabei liegt bevorzugt das auf Gew.-% in der ersten Beschichtungszusammensetzung bezogene Verhältnis von Kalziumkarbonat zu Aluminium(hydr)oxid in einem Bereich von 10 : 1 bis 3 : 1.A third variant alternative to the first and second variants is obtained when the first coating composition is the at least two pigments

• Contains calcium carbonate and aluminum (hydr) oxide,
• ■ most preferably calcium carbonate and aluminum (hydr) oxide exclusively.

In this case, the ratio of calcium carbonate to aluminum (hydr) oxide based on% by weight in the first coating composition is preferably in a range from 10: 1 to 3: 1.

The calcium carbonate which is preferably used in the first embodiment of the proposed embodiment is very particularly preferably in precipitated form with a crystal form as calcite and, in a very preferred embodiment, has an average particle size in a range from 0.1 μm to 0.3 μm, and a specific surface area (BET) according to DIN 66132 in a range of 5-15 m ² / g. An example of this is Socal P3 (company: Solvay) called.

Furthermore, in the proposed embodiments, the silicon (di) oxide preferably used in the first coating composition is most preferably in precipitated form and in a very preferred embodiment has an average particle size in a range from 3.0 μm to 6.0 μm , and a specific surface area (BET) according to DIN 66132 in a range of 40-200 m ² / g. An example of this is Sipernat 350 (company: Evonik).

Further, in the proposed embodiments, the preferred aluminum hydroxide in the first coating composition is in platelet form, and in a very preferred embodiment has an average particle size in a range of 1.0 μm to 1.5 μm, and a specific surface area (BET ) according to DIN 66132 in a range of 5-15 m ² / g. An example of this is Martifin OL107 (company: Martinswerke) called.

Furthermore, in a very preferred embodiment, the kaolin preferably used in the first embodiment of the proposed embodiments has an average particle size in a range from 0.5 μm to 1.0 μm, and a specific surface area (BET) according to DIN 66132 in one Range of 5-15 m ² / g. An example of this is Miragloss 90 (company: BASF).

Suitable binders for incorporation into the first coating composition are, for example, water-soluble binders such as starch, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, polyvinyl alcohols, modified polyvinyl alcohols, ethylene-vinyl alcohol copolymers, sodium polyacrylates, acrylamide-acrylate copolymers, acrylamide-acrylate-methacrylate Terpolymers and alkali metal salts of styrene-maleic anhydride copolymers or ethylene-maleic anhydride copolymers, which binders may 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 first coating composition. For the purposes of the present invention, polyvinyl alcohol, styrene-butadiene copolymer or, better, polyvinyl alcohol in combination with styrene-butadiene copolymer are particularly preferred binders which, based on the total weight of the first coating composition, are in a range from 10 to 20% by weight. % are included in the first coating composition.

Furthermore, in the numerous series of experiments already mentioned above, it was found that the ratio _total pigment: _total binder, based on weight percent in the first coating _composition, ideally ranges from 1: 1 to 5: 1, more preferably from 2.5: 1 to 3.5: 1.

To avoid sticking to a thermal head and avoiding excessive wear of the thermal head, the first coating composition for forming the thermosensitive recording layer may further contain slip 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.

In a particularly preferred embodiment, the first coating composition contains at least one sensitiser selected from the list comprising: stearic acid amide, dimethylsulfone, 2- (2H-benzotriazol-2-yl) -p-cresol - also known as Tinuvin ^® P from Ciba Specialty Chemicals Inc., dimethyl terephthalate - also abbreviated to DMT, methylol stearamide, benzyl p-benzyloxy benzoate, p-benzylbiphenyl, 1,2-di (phenoxy) ethane, di (4-methylphenoxy ) ethane - also known by the abbreviation EGTE, dibenzyl oxalate, benzyl naphthyl ether - also known as BNE, and diphenyl sulfone. Therein, di (4-methylphenoxy) ethane and benzyl naphthyl ether are very particularly preferred.

In the numerous series of experiments already mentioned above, the inventors recognized that a _{total developer} : sensitizer ratio based on the weight percent in the first coating _{composition is} in a range of 1.2: 1 to 2.0: 1.

In a preferred embodiment, the proposed recording material provides for the formation of a pigmented intermediate layer of a second coating composition arranged between the heat-sensitive recording layer and the substrate. This second coating composition contains binders and preferably a mixture of organic pigments and inorganic pigments.

The inorganic pigments are thereby preferred, individually or in combination with one another, selected from the list, comprising: silicon (di) oxide, bentonite, talc, calcined kaolin, calcium carbonate and aluminum oxide and here in particular boehmite. The above inorganic pigments, individually or in combination with one another, selected from the list above, are quoted as one of the list comprising: calcined kaolin, calcium carbonate and aluminum oxide, and here especially 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. Pigment mixtures of different organic pigments are conceivable.

In addition to the inorganic and optionally also organic pigments, the second 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 admixture of at least one natural polymer, more preferably starch, is a particularly suitable embodiment. In the context of inorganic pigment testing, it has further been found that with a binder to pigment ratio within the second coating composition is between 3: 7 and 1: 9, in each case based on wt .-%, a particularly suitable embodiment is present.

• ■ 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 - insbesondere eine Sicherheitsmarkierung aufweisen. Dabei erfreuen sich insbesondere Wasserzeichen einer besonderer Beliebtheit, 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.

Im Sinne der vorliegenden Erfindung gelten alle oben genannten Sicherheitsmerkmale als bevorzugt, die entweder allein oder in Kombination mit weiteren Sicherheitsmerkmalen zum Einsatz kommen können. Innerhalb dieser vorstehenden Sicherheitsmerkmale gelten die echten Wasserzeichen als ganz besonders bevorzugt.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,
• ■ Paper provided with a polyolefin coating on at least one side

is used. In this case, this paper - especially in its intended use as a ticket material - in particular have a security mark. In particular, enjoy watermark of particular popularity, 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,
• Halbchten, so-called Moletten watermarks, which are produced by embossing the still wet paper in the press section of a paper machine, and finally
• spurious watermarks, 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, which can be used either alone or in combination with other security features. Within these security features above, the true watermarks are considered to be most preferred.

• ■ Ausbilden eines bahnförmigen Substrates;
• ■ Vorbereiten einer ersten Beschichtungszusammensetzung, wobei diese erste Beschichtungszusammensetzung mindestens umfasst:
  • ein oder mehrere Farbstoffvorläufer,
  • als Entwickler N-(p-toluensulphonyl)-N'-3-(p-toluensulphonyl-Oxy-phenyl)-harnstoff gemäß der folgenden Formel (1):
    
  • ein Bindemittel,
  • Pigment, ausgesucht aus der Liste, umfassend: Kaolin, Silizium(di)oxid, Bentonit, Talkum, Kalziumkarbonat sowie Aluminiumoxid und hier besonders Böhmit wobei die erste Beschichtungszusammensetzung als Pigment mindestens eine Pigmentkombination enthält und wobei die Pigmentkombination ausgesucht ist aus der Liste, umfassend:
    • Kalziumkarbonat und Silizium(di)oxid,
    • Aluminium(hydr)oxid und Silizium(di)oxid,
    • Kalziumkarbonat und Aluminium(hydr)oxid;
• ■ Aufbringen der vorbereiteten ersten Beschichtungszusammensetzung zur Ausbildung einer wärmeempfindlichen Aufzeichnungsschicht auf dem Substrat;
• ■ Trocknen der ersten Beschichtungszusammensetzung;
• ■ Aufrollen des bahnförmigen Substrates mit der ausgebildeten wärmeempfindlichen Aufzeichnungsschicht.

The invention also relates, to the same extent, to a process for the preparation of a heat-sensitive recording material in all the already proposed here Embodiments and Variants. Such a method comprises at least the following method steps:

• ■ forming a web-shaped substrate;
• Preparing a first coating composition, said first coating composition comprising at least
  • one or more dye precursors,
  • as a developer, N- (p-toluenesulphonyl) -N'-3- (p-toluenesulphonyl-oxy-phenyl) urea according to the following formula (1):
    
  • a binder,
  • A pigment selected from the list, comprising: kaolin, silicon (di) oxide, bentonite, talc, calcium carbonate, and alumina, and especially boehmite, wherein the first coating composition contains as pigment at least one pigment combination and wherein the pigment combination is selected from the list comprising:
    • Calcium carbonate and silicon (di) oxide,
    • Aluminum (hydr) oxide and silicon (di) oxide,
    • Calcium carbonate and aluminum (hydr) oxide;
• Applying the prepared first coating composition to form a heat-sensitive recording layer on the substrate;
• Drying the first coating composition;
• ■ rolling up the web-shaped substrate with the formed heat-sensitive recording layer.

The web-shaped substrate is formed, for example, on a paper machine in which a paper pulp of different pulps, optionally groundwood, fillers and water is applied in at least one upstream mixing chest is and where to this paper pulp before being fed to the paper machine preferably further ingredients such as resin size for engine sizing and other conventional additives such as pigments, Nuancierfarbstoffe and / or optical brightener may be added. In particular, when such a paper machine is a fourdrinier paper machine, it is a preferred embodiment if a dandy is placed above the papermachine screen with the aid of which a genuine watermark is pressed into the paper web.

• ■ Vorbereiten einer zweiten Beschichtungszusammensetzung, wobei die zweite Beschichtungszusammensetzung organische Pigmente und anorganische Pigmente umfasst, die anorganischen Pigmente ganz besonders bevorzugt ausgesucht aus der Liste, umfassend: kalziniertes Kaolin, Kalziumkarbonat sowie Aluminiumoxid und hier besonders Böhmit;
• ■ Aufbringen der vorbereiteten zweiten Beschichtungszusammensetzung zur Ausbildung einer zwischen Substrat und wärmeempfindlicher Aufzeichnungsschicht angeordneten pigmentierten Zwischenschicht;
• ■ Trocknen der zweiten Beschichtungszusammensetzung;

wobei diese mindestens drei zusätzlichen Verfahrensschritte vor den Verfahrensschritt "Aufbringen der vorbereiteten ersten Beschichtungszusammensetzung zur Ausbildung einer wärmeempfindlichen Aufzeichnungsschicht auf dem Substrat" einzuschieben sind. Es ist möglich, wenn die pigmentierte Zwischenschicht schon auf der Papiermaschineausgebildet wird, wobei sich neben der Papiermaschine auch alternativ eine separate Streichmaschine, in der dann auch die wärmeempfindliche Aufzeichnungsschicht aufgetragen werden kann, anbietet.The web of paper provided as a web-shaped substrate, optionally provided with a genuine watermark produced by means of a dandy cutter, in one possible embodiment of the method proposed here still receives a pigmented intermediate layer within the paper machine. For this purpose, the method comprises the at least three additional method steps:

• ■ Preparing a second coating composition, wherein the second coating composition comprises organic pigments and inorganic pigments, most preferably selected from the list of inorganic pigments, comprising: calcined kaolin, calcium carbonate and alumina, and here especially boehmite;
• Applying the prepared second coating composition to form a pigmented intermediate layer disposed between the substrate and the heat-sensitive recording layer;
• Drying the second coating composition;

these at least three additional process steps are to be inserted before the process step "applying the prepared first coating composition for forming a heat-sensitive recording layer on the substrate". It is possible if the pigmented intermediate layer is already being formed on the paper machine, wherein, in addition to the paper machine, a separate coating machine, in which the heat-sensitive recording layer can then also be applied, is offered as an alternative.

Preferably, the second 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 methods, the intermediate layer can make a positive contribution to leveling of the substrate surface, thereby reducing the amount of applied mass of the first coating composition for forming the thermosensitive recording layer. The subsequent drying of the coating composition of this second 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 means of Egoutteur, genuine watermarked and acted upon with a pigmented intermediate layer 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.

• □ mittels einer Druckmaschine ein unechtes Wasserzeichen unter Nutzung eines farblosen oder leicht getönten Lacks ausgebildet werden. Als Druckmaschinen bieten sich dabei insbesondere solche auf Analogdruck-Basis an. Dabei werden als Analogdruck im Sinne dieser Erfindung alle Druckverfahren bezeichnet, die mit Druckplatte bzw. -zylinder arbeiten, wozu Tiefdruck, Siebdruck, Offsetdruck und in einer ganz besonders bevorzugten Ausführung Flexodruck gehört. Ganz besonders bevorzugt ist der zur Ausbildung des unechten Wasserzeichens genutzte Lack UVvernetzend, so dass der Druckauftrag mittels UV-Bestrahlung rasch vernetzt werden kann.
• □ mittels eines Digitaldruckers, wie beispielsweise ein Inkjet-Drucker, ein unechtes Wasserzeichen unter Nutzung einer farblosen oder leicht getönten Tinte ausgebildet werden. Vorteil eines solchen Verfahrensschrittes sind die vergleichsweise geringen Kosten und die höchst flexibel und individuell auszubildenden Wasserzeichen beispielsweise in Form von Barcodes.

Alternatively or in addition to the real watermark can now

• □ a fake watermark is formed by means of a printing press using a colorless or slightly tinted lacquer. Particularly suitable as printing machines are those based on analog printing. Here are referred to as analog printing in the context of this invention, all printing processes that work with printing plate or cylinder, including gravure, screen printing, offset printing and in a very particularly preferred embodiment flexographic belongs. Most preferably, the varnish used to form the spurious watermark is UV crosslinking, so that the print job can be rapidly crosslinked by means of UV irradiation.
• □ by means of a digital printer, such as an inkjet printer, formed a fake watermark using a colorless or slightly tinted ink. The advantage of such a method step is the comparatively low costs and the highly flexible and individually traceable watermarks, for example in the form of barcodes.

• □ wird auf dieses Substrat, das gegebenenfalls bereits ein echtes und/oder ein unechtes Wasserzeichen trägt
  oder
• □ wird auf die pigmentierte Zwischenschicht, ausgebildet auf dem Substrat, gegebenenfalls ein echtes und/oder ein unechtes Wasserzeichen tragend,

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 Beschichtungsmasse 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 of a spool

• □ is applied to this substrate, which may already have a real and / or a fake watermark
  or
• □ is applied to the pigmented intermediate layer, formed on the substrate, optionally a true and / or a fake watermark,

applied 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 coating composition is usually done by a method in which heat is supplied, as is done by hot-air floating 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 .

The method for producing a heat-sensitive recording material, as proposed here, provides, in a preferred variant, for smoothing the substrate with the first coating composition now applied and dried. 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. Further, a smoother surface of the thermosensitive recording layer by improved contact with the thermal head promotes heat transfer and thus the sensitivity of this thermosensitive 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 experiments and test series of heat-sensitive recording materials produced by one of the methods disclosed herein, could show their superior effect in their use as a ticket. The tickets have excellent resistance to moisture and moisture on the one hand and plasticizers on the other.

In particular, however, the recording material proposed here in their use as tickets by excellent running behavior within the often used in the operators of bus lines and rail thermal printer, including the low abrasiveness of the recording material to the thermal head out as well as in particular the keeping away in the heat-sensitive Recording layer during typeface formation resulting melt from the thermal head.

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. In the comments on the organic pigments of the pigment-containing interlayer, 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.

The invention will be further elucidated with reference to the following Examples 1 to 4 and Comparative Examples 5 to 6:

As a web-shaped substrate is on a fourdrinier paper machine from bleached and ground hardwood and softwood pulps with the addition of 0.6 wt .-% (atro) resin size, based on the total solids content (atro) of the paper machine supplied pulp, and with the addition of more conventional additives a backing paper having a basis weight of 53 g / m ² produced. By using an egg cutter traveling on the wire of the paper machine, the web-shaped substrate obtains a true watermark incorporated into the fiber mass.

• □ eine Pigmentmischung aus anorganischem Pigment und kalziniertem Kaolin im Verhältnis von 12 : 88,
• □ eine Bindemittelmischung aus Styrol-Butadien-Latex und Stärke sowie
• □ weitere Hilfsmittel

aufweisende Zwischenschicht mit einem Bindemittel_gesamt-Pigment_gesamt-Verhältnis von 1 : 5 bei einer flächenbezogenen Masse von 9 g/m² aufgebracht.Even within the paper machine - for the inventive examples 1 to 3 and for the comparative examples 5 and 6 - on one side of the web-shaped substrate using a doctor blade a

• □ a pigment mixture of inorganic pigment and calcined kaolin in the ratio of 12:88,
• □ a binder mixture of styrene-butadiene latex and starch as well
• □ further aids

comprising intermediate layer with a binder _total pigment _total ratio of 1: 5 applied at a basis weight of 9 g / m ² .

In this pigmented intermediate layer - or for the inventive Example 4 on the substrate - is applied by means of roller blade coating device each have a heat-sensitive recording layers with a respective basis weight of 4.4 g / m ² . The aqueous coating compositions used for this purpose comprise the following components according to the formulations reproduced in Table 1, the numbers in Table 1 in each case representing parts by weight:

On the finished papers of Examples 1 to 4 and Comparative Examples 5 and 6 are each a Thermoprobeausdruck with a device of the type Atlantek 400 Fa. Atlantek (USA) formed and to determine the sensitivity the printing density determined with the densitometer Gretag MacBeth TYPE D19C NB / U (Gretag MacBeth, 8105 Regensdorf, Switzerland).

To determine the resistance to water, samples of the four examples according to the invention and the two comparative examples with the respective thermoprobeable printings are immersed for 20 minutes in a water bath (deionized water, 23 ° C.). Then the samples are allowed to drain, then allowed to rest for 24 hours at 23 ° C and 50% humidity. This is followed by a visual assessment of the thermal printouts after the water bath with reference thermoprinting prints without aftertreatment.

To determine the resistance to plasticizers of samples to the respective thermal print sample a piece of TESA ^® graphic film 57331 is adhered. Subsequently, the samples are allowed to rest for 24 hours at 23 ° C and 50% humidity. The following is a visual assessment of the thermal test prints with the piece TESA ^® graphic film 57331 with reference Thermoprobe Print without aftertreatment.

To determine the print head deposition using a Axiohm printer " APOS (Axiohm Point of Sales) Premium Printer " (company: Axiohm, Le Plessis Robinson 92 - France) with built-Axiohm printhead a checkerboard pattern over 500 m on samples of the four invention Examples and the two comparative examples printed. Subsequently, the Axiohm printhead is visually evaluated for deposits.

To determine the stampability: stamp impressions are applied with any stamp using a commercially available stamp pad on samples of the four examples according to the invention and the two comparative examples. 10 seconds after the stamping an attempt is made to manually wipe the respective typeface with a dry filter paper. Not wipeable applies the typeface, if it is still readable.

To determine the barcode readability, a barcode is printed on samples of the four examples according to the invention and the two comparative examples using a device of the Atlantek 400 type from Atlantek (USA). With a Tru Check 201 R reader from Webscan, Inc. 1254 Sherman Drive, Longmont (Co, USA), the barcode is analyzed and rated according to ANSI according to international standard ISO 15416.

The results of all the above-mentioned evaluations are included in Table 1 above. They again show the superiority of the proposed embodiments in all the embodiments and variants proposed here.

Claims (16)

1. Recording material having a web-form substrate and a heat-sensitive recording layer as the outer layer that is the final layer towards the outside, the heat-sensitive recording layer being formed from a first coating composition having at least:

   ■ one or more dye precursors,

   ■ as developer, N-(p-toluenesulphonyl)-N'-3-(p-toluenesulphonyloxy-phenyl)-urea in accordance with formula (1) below:

   

   ■ a binder,

   ■ pigment, selected from the list comprising: kaolin, silicon (di)oxide, bentonite, talcum, calcium carbonate and also aluminium oxide and in this case especially boehmite,

   characterised in that

   □ the first coating composition contains as pigment at least one pigment combination, the pigment combination being selected from the list comprising:

   - calcium carbonate and silicon (di)oxide,

   - aluminium (hydr)oxide and silicon (di)oxide,

   - calcium carbonate and aluminium (hydr)oxide.
2. Recording material according to patent claim 1, characterised in that the ratio calcium carbonate : silicon (di)oxide, based on % by weight in the first coating composition, lies in a range of from 2 : 1 to 1.2 : 1.
3. Recording material according to patent claim 1, characterised in that the ratio aluminium (hydr)oxide : silicon (di)oxide, based on % by weight in the first coating composition, lies in a range of from 25 : 1 to 5 : 1.
4. Recording material according to patent claim 1, characterised in that the ratio calcium carbonate : aluminium (hydr)oxide, based on % by weight in the first coating composition, lies in a range of from 10 : 1 to 3 : 1.
5. Recording material according to any one of patent claims 1, 2 and 4, characterised in that the calcium carbonate comprises a precipitated calcium carbonate having an average particle size in a range of from 0.1 µm to 0.3 µm, and a specific surface area (BET) in accordance with DIN 66132 in a range of from 5 to 15 m²/g_.
6. Recording material according to any one of patent claims 1 to 3, characterised in that the silicon (di)oxide has an average particle size in a range of from 3 µm to 6 µm, and a specific surface area (BET) in accordance with DIN 66132 in a range of from 40 to 200 m²/g.
7. Recording material according to any one of patent claims 1, 3 and 4, characterised in that the aluminium hydroxide has an average particle size in a range of from 1 µm to 1.5 µm, and a specific surface area (BET) in accordance with DIN 66132 in a range of from 5 to 15 m²/g.
8. Recording material according to patent claim 1, characterised in that the kaolin has an average particle size in a range of from 0.5 µm to 1.0 µm, and a specific surface area (BET) in accordance with DIN 66132 in a range of from 5 to 15 m²/g.
9. Recording material according to any one of patent claims 1 to 8, characterised in that the binder for incorporation into the first coating composition is or contains at least one water-soluble binder, selected from the list comprising: starch, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohols, modified polyvinyl alcohols.
10. Recording material according to any one of patent claims 1 to 9, characterised in that the binder for incorporation into the first coating composition is or contains at least one water-insoluble latex binder, selected from the list comprising: styrene-butadiene copolymers, acrylonitrile-butadiene copolymers and methyl acrylate-butadiene copolymers.
11. Recording material according to any one of patent claims 1 to 10, characterised in that the ratio pigment_total : binder_total, based on % by weight in the first coating composition, lies in a range of from 2.5 : 1 to 3.5 : 1.
12. Recording material according to any one of patent claims 1 to 11, characterised in that the first coating composition contains at least one sensitiser, selected from the list comprising: di-(4-methylphenoxy)-ethane and benzyl naphthyl ether.
13. Recording material according to any one of claims 1 to 12, characterised in that a pigmented intermediate layer is arranged between the heat-sensitive recording layer and the substrate, which intermediate layer contains binder, organic pigments and inorganic pigments.
14. Process for producing a heat-sensitive recording material according to any one of claims 1 to 13, comprising at least the following process steps:

    ■ forming a web-form substrate;

    ■ preparing a first coating composition, this first coating composition comprising at least:

    - one or more dye precursors,

    - as developer, N-(p-toluenesulphonyl)-N'-3-(p-toluenesulphonyloxy-phenyl)-urea in accordance with formula (1) below:

    

    - a binder,

    - pigment, selected from the list comprising: kaolin, silicon (di)oxide, bentonite, talcum, calcium carbonate and also aluminium oxide and in this case especially boehmite,

    the first coating composition containing as pigment at least one pigment combination and the pigment combination being selected from the list comprising:

    - calcium carbonate and silicon (di)oxide,

    - aluminium (hydr)oxide and silicon (di)oxide,

    - calcium carbonate and aluminium (hydr)oxide;

    ■ applying the prepared first coating composition to form a heat-sensitive recording layer on the substrate;

    ■ drying the first coating composition;

    ■ rolling up the web-form substrate having the heat-sensitive recording layer that has been formed.
15. Process according to patent claim 14, characterised in that the process comprises the at least three additional process steps:

    ■ preparation of a second coating composition, the second coating composition comprising organic pigments and inorganic pigments, the inorganic pigments being selected from the list comprising: calcined kaolin, calcium carbonate and also aluminium oxide and in this case especially boehmite;

    ■ application of the prepared second coating composition to form a pigmented intermediate layer arranged between the substrate and the heat-sensitive recording layer;

    ■ drying of the second coating composition;

    these at least three additional process steps being introduced prior to the process step "applying the prepared first coating composition to form a heat-sensitive recording layer on the substrate".
16. Use of the recording material according to any one of claims 1 to 13 for issuing travel tickets on a correspondingly suitable thermal printer.