Non-phenolic color developer and thermosensitive recording material

Abstract

Disclosed is a developer of formula (I), (Ar 1 -SO2-NH-) m -Y-( -NH-C(O)-NH-SO2-Ar 2 ) n (I), wherein Ar 1 is an unsubstituted or substituted aromatic group, Ar 2 is an unsubstituted or substituted phenyl group, Y is a benzene group or a naphthalene group substituted at least (m + n) times, and Y is substituted such that at least one Ar 2 -SO2-NH-C(O)-NH- group is in the ortho position to at least one Ar 1 -SO2-NH group; a thermosensitive recording material is disclosed, which comprises a carrier substrate and a thermosensitive color-forming layer containing at least one color former and at least one phenol-free developer, wherein at least one developer is a compound of formula (I); and a method for preparing the thermosensitive recording material is disclosed.

Description

Technical Field

[0001] The present invention relates to a developer, a thermal recording material including a carrier substrate and a thermosensitive coloring layer containing at least one color former and at least one non-phenolic developer, and a method for producing the same. Background Art

[0002] Thermal recording materials having a thermosensitive coloring layer (thermal reaction layer) applied to a carrier substrate for direct thermal printing applications have long been known. A color former and a developer are usually present in the thermosensitive coloring layer, and the color former and the developer react with each other under heat and cause color development. In this case, (bis)phenolic developers are often used. Also known are thermal recording materials in which the thermosensitive coloring layer contains a non-phenolic developer. These materials have been developed to improve the resistance of the text image especially when the printed thermal recording material is stored for a long time or when it comes into contact with a hydrophobic substance (such as a plasticizer-containing material or oil). In particular, in the context of the public discussion about the potential toxicity of (bis)phenolic chemicals, the interest in non-phenolic developers has increased significantly. The aim here is to avoid the toxic disadvantages of phenolic developers, but at least maintain, preferably improve, the technical properties that can be achieved with phenolic developers.

[0003] The prior art regarding non-phenolic developers can identify common structural features even in the case of the large chemical diversity of these substances.

[0004] Therefore, the 1,3-disubstituted urea group structure (Y-NH-CO-NH-Z) is a common feature of a large number of non-phenolic developers. By appropriately selecting the groups Y and Z, the functional properties related to the suitability as a developer can be adjusted.

[0005] Developers having a sulfonyl-urea structure (-SO2-NH-CO-NH-) are widely used because they can be prepared relatively easily and the thermal recording materials prepared using them have good application technical properties.

[0006] EP 0 526 072 A1 discloses developers from the class of aromatic sulfonyl(thio)urea compounds of the following formula

[0007] Ar’-SO2-NH-C(X)-NH-Ar,

[0008] wherein, X = O or S, and Ar and Ar’ are aromatic groups.

[0009] Thermosensitive recording materials characterized by improved image permanence can be obtained by using these developers. In addition, thermosensitive recording materials based on these developers have usable thermal print sensitivity with good surface whiteness, so that high printing density can be relatively easily produced using a commercial thermal printer in the case of formulating a corresponding thermosensitive color-forming layer.

[0010] The aromatic and heteroaromatic sulfonyl(thio)urea compounds (X = S or O) and / or sulfonylguanidines (X = NH) of the above formula, wherein Ar is connected to another aromatic group through a divalent linking group. The non-phenolic developer 4-methyl-N-(((3-(((4-methylphenyl)sulfonyl)oxy)phenyl)amino)carbonyl)benzenesulfonamide (trade name Pergafast BASF) widely used in practice is characterized by the balance of the application technical properties of the thermosensitive recording material prepared using this developer. In particular, they have good dynamic response sensitivity and acceptable resistance of the printed matter to hydrophobic substances.

[0011] Sulfonylurea units connected through a divalent or polyvalent linking group A, such as bis-sulfonylurea compounds of the following formula, have also been described many times as developers (see EP 0 535 887 A1, EP 0 542 556 A1, EP 0 604 832 B1, EP 0 620122 A1 and EP 1 044 824 A2)

[0012] (Ar-SO2-NH-C(O)-NH-)2A,

[0013] wherein Ar is an aromatic group.

[0014] In practice, N,N'-(methylenebis(4,1-phenyleneiminocarbonyl))bis(4-methyl-benzenesulfonamide) (B-TUM) is particularly recognized (A = CH2, Ar = 4-methylphenyl).

[0015] The combination of an N-sulfonyl(thio)carbamate group of the following formula with a sulfonylurea structure is the subject of JP H 0 664 335,

[0016] (Ar-SO2-NH-C(O)-NH-) n (Ar-SO2-NH-C(O)-X-) m A,

[0017] wherein Ar is an aromatic group, A is an (m + n)-valent organic linking group and X = O or S.

[0018] For thermosensitive recording materials prepared using these color developers, an improved resistance of the lettering to hydrophobic reagents is described. However, when a chemically homogeneous substance is desired, the synthetic routes to these color developers become particularly problematic.

[0019] JP H 0 958 242 combines a sulfonylurea structure with a primary sulfonamide group to obtain a color developer of the following formula

[0020] R-SO2-NH-C(X)-NH-C6H4-SO2-NH2.

[0021] JP H 11-263067 discloses a color developer formed from a (thio)urea structure and a sulfonyl(thio)urea structure linked by an aromatic linking group unit of the following formula

[0022] Ar 1 -NH-C(X)-NH-A-SO2-NH-C(X)-NH-Ar 2 ,

[0023] wherein, X = O or S, and Ar 1 and Ar 2 are aromatic groups.

[0024] Common to thermosensitive recording materials obtained using non-phenolic color developers based on sulfonylurea chemistry is that they exhibit good performance in terms of properties relevant to many applications, but disclose weaknesses in other respects.

[0025] Thus, with respect to hydrophobic substances, high durability of the lettering often goes hand in hand, for example, with a moderate response sensitivity (dynamic sensitivity) in thermal printers, which can only be effectively improved by means of a large number of very special melting aids (special heat solvents, special sensitizers).

[0026] On the other hand, relatively slightly higher dynamic sensitivity values are achieved using specific non-phenolic color developers, yet the durability of the lettering therein is medium. This defect can be remedied by means of anti-aging agents (stabilizers), but at the cost of a complex and expensive formulation of the recording layer. Summary of the Invention

[0027] The object of the present invention is therefore to eliminate the aforementioned disadvantages of the prior art. In particular, the object of the present invention is to provide a thermosensitive recording material which has a high dynamic sensitivity (high response sensitivity in a printer) and at least reaches the level of thermosensitive recording materials based on non-phenolic developers of the prior art with respect to other application technology-related performance characteristics, without relying on special formulation components of the thermosensitive functional layer, such as anti-aging agents, or special melting aids with limited availability and / or high price. The main object of the present invention is to provide a developer which can form an image with a high printing density without simultaneously bringing an undesirable influence on the starting temperature of the recording material (static sensitivity). At the same time, compared with the prior art, the thermosensitive recording material should achieve good durability, especially for hydrophobic reagents.

[0028] According to the present invention, the object is solved by using the compound according to claim 1 in the thermosensitive recording material according to claim 9.

[0029] It has surprisingly been found that a thermosensitive recording material can be obtained by using a developer of a specific substitution variant of formula (I), which is characterized by a high dynamic sensitivity and cannot be produced by a comparable formulation for a thermosensitive recording material of another substitution variant of a developer having the same compound class. The recording material prepared with the developer according to the present invention also has good resistance to hydrophobic reagents, which is at least equivalent to that of the prior art.

[0030] The compound according to claim 1 has the formula (I),

[0031] Ar 1 (SO2-NH-) m -Y-(-NH-C(O)-NH-SO2-Ar 2 ) n (I),

[0032] wherein Ar 1 is an unsubstituted or substituted aromatic group, Ar 2 is an unsubstituted or substituted phenyl group, Y represents at least one benzene group or naphthalene group substituted (m + n) times, and Y is substituted such that at least one Ar 2 -SO2-NH-C(O)-NH- group is in the ortho position, i.e., the 1,2-position, of at least one Ar 1 -SO2-NH- group.

[0033] Preferably, m is equal to 1 and n is greater than or equal to 1.

[0034] Preferably, n is equal to 1 and m is 1 or 2.

[0035] Preferably, Ar1 is an unsubstituted or substituted phenyl group or an unsubstituted or substituted 2-naphthyl group.

[0036] Particularly preferably, Ar 1 is an unsubstituted phenyl group or a monosubstituted phenyl group.

[0037] Preferably, the monosubstituted phenyl group is substituted by the following: C1-C5 alkyl, alkenyl, alkynyl, benzyl, RO-, halogen, formyl, ROC-, RO2C-, CN-, NO2-, R-SO2O-, RO-SO2-, R-NH-SO2-, R-SO2NH-, R-NH-CO-NH-, R-SO2-NH-CO-NH-, R-NH-CO-NH-SO2- or R-CO-NH- group, where R is C1-C5 alkyl, alkenyl, alkynyl, phenyl, tolyl or benzyl, preferably phenyl or p-tolyl.

[0038] Preferred substituents are C1-C5 alkyl, RO-, halogen, RO2C-, R-SO2O-, R-NH-CO-NH- and R-SO2-NH-CO-NH- groups.

[0039] Preferably, Ar 2 is an unsubstituted phenyl group or a monosubstituted phenyl group, especially a phenyl group substituted by C1-C4 alkyl, particularly preferably a phenyl group substituted by methyl.

[0040] In a particularly preferred embodiment, Ar 1 is an unsubstituted phenyl group or a monosubstituted phenyl group, Ar 2 is an unsubstituted phenyl group or a monosubstituted phenyl group, and Y is a benzene group substituted (m + n) times.

[0041] Particularly preferred compounds of formula (I) are shown in Table 1 below.

[0042] Table 1: Preferred compounds of formula (I) having a Y group, an Ar 1 group, an Ar 2 group, and given meanings of m and n (R = as described above)

[0043] Y <![CDATA[Ar 1 > <![CDATA[Ar 2 > m n I Phenylene Phenyl Phenyl 1 1 II, XIV, XVII Phenylene Phenyl <![CDATA[C1-C4 alkyl-substituted phenyl]]> 1 1 III, XV, XVIII Phenylene <![CDATA[C1-C5 alkyl-substituted phenyl]]> Phenyl 1 1 IV, V, VI, XVI, XIX Phenylene <![CDATA[C1-C5 alkyl-substituted phenyl]]> <![CDATA[C1-C4 alkyl-substituted phenyl]]> 1 1 VII Phenylene RO-Substituted Phenyl <![CDATA[C1-C4 alkyl-substituted phenyl]]> 1 1 VIII Phenylene Halogen-Substituted Phenyl <![CDATA[C1-C4 alkyl-substituted phenyl]]> 1 1 IX Phenylene R-CO-NH-Substituted Phenyl <![CDATA[C1-C4 alkyl-substituted phenyl]]> 1 1 X Phenylene Nitro-Substituted Phenyl <![CDATA[C1-C4 alkyl-substituted phenyl]]> 1 1 XI Phenylene <![CDATA[RO2C-substituted phenyl]]> <![CDATA[C1-C4 alkyl-substituted phenyl]]> 1 1 XII Phenylene Naphthyl <![CDATA[C1-C4 alkyl-substituted phenyl]]> 1 1 XIII Phenylene Benzyl <![CDATA[C1-C4 alkyl-substituted phenyl]]> 1 1 XXI Trisubstituted Benzene <![CDATA[C1-C5 alkyl-substituted phenyl]]> Phenyl 1 2 XX, XXII, XXIII, XXIV Trisubstituted Benzene <![CDATA[C1-C5 alkyl-substituted phenyl]]> <![CDATA[C1-C4 alkyl-substituted phenyl]]> 1 2

[0044] The preparation of the compounds of formula (I) according to the present invention can be carried out according to methods known per se.

[0045] Reaction Scheme 1 illustrates possible synthetic routes for the compounds of formula (I) according to the present invention with examples of Compounds I to XIX (see Table 2).

[0046]

[0047] Reaction Scheme 1 (Ar 1 、Ar 2 : see Table 2)

[0048] Reaction Scheme 2 illustrates possible synthetic routes of the compounds of formula (I) according to the invention by way of examples of compounds XX to XXIV (see Table 2).

[0049]

[0050] Reaction Scheme 2 (Ar 1 、Ar 2 : see Table 2)

[0051] Compound XX (see Table 2) falling within the compounds of formula (I) according to the invention can be prepared as follows: starting from 2,6-dinitroaniline, it is first converted into 1,2-diamino-3-nitrobenzene according to the following Reaction Scheme 3 (V. Milata, J. Saloň, Org. Prep. Proceed. Int., 31(3), 347(1999)), and then into the end product according to the described method.

[0052]

[0053] Reaction Scheme 3

[0054] The preferred embodiments described for the compounds of formula (I) also apply to their preparation methods.

[0055] As described above, the present invention also relates to a thermosensitive recording material comprising a carrier substrate and a thermosensitive coloring layer containing at least one color former and at least one phenol-free developer, wherein the at least one phenol-free developer is a compound of formula (I) as described above.

[0056] The compound of formula (I) is preferably present in an amount of about 3 to about 35% by weight, particularly preferably in an amount of about 10 to about 25% by weight, based on the total solids content of the thermosensitive layer.

[0057] The choice of the carrier substrate is not critical. However, it is preferred to use paper, synthetic paper and / or plastic foil as the carrier substrate.

[0058] Optionally, there is at least one additional intermediate layer between the carrier substrate and the thermosensitive layer, the purpose of which is to improve the surface smoothness of the carrier substrate for the thermosensitive layer and to ensure a thermal barrier between the carrier substrate and the thermosensitive layer. Preferably, organic hollow bead pigments and / or calcined kaolin are used in this intermediate layer. At least one protective layer and / or at least one layer facilitating printability may also be present in the thermosensitive recording material according to the invention, and these layers can be applied to the front or back surface of the substrate.

[0059] Regarding the selection of the coupler, there are also no essential limitations in the present invention. However, preferably, the coupler is a dye of the triphenylmethane type, fluorane type, azaphthalide type, and / or fluorene type. A very particularly preferred coupler is a dye of the fluorane type, because it can provide a recording material with an attractive cost performance ratio due to its availability and balanced properties related to applications.

[0060] Particularly preferred dyes of the fluorane type are:

[0061] 3 - Diethylamino - 6 - methyl - 7 - anilino fluorane,

[0062] 3-(N - Ethyl - N - p - tolylamino)-6 - methyl - 7 - anilino fluorane,

[0063] 3-(N - Ethyl - N - isoamylamino)-6 - methyl - 7 - anilino fluorane,

[0064] 3 - Diethylamino - 6 - methyl - 7-(o,p - dimethylanilino) fluorane,

[0065] 3 - Pyrrolidino - 6 - methyl - 7 - anilino fluorane,

[0066] 3-(Cyclohexyl - N - methylamino)-6 - methyl - 7 - anilino fluorane,

[0067] 3 - Diethylamino - 7-(m - trifluoromethylanilino) fluorane,

[0068] 3 - N - Di - n - butylamine - 6 - methyl - 7 - anilino fluorane,

[0069] 3 - Diethylamino - 6 - methyl - 7-(m - methylanilino) fluorane,

[0070] 3 - N - Di - n - butylamine - 7-(o - chloroanilino) fluorane,

[0071] 3-(N - Ethyl - N - tetrahydrofurfurylamine)-6 - methyl - 7 - anilino - fluorane,

[0072] 3-(N - Methyl - N - propylamine)-6 - methyl - 7 - anilino fluorane,

[0073] 3-(N - Ethyl - N - ethoxypropylamine)-6 - methyl - 7 - anilino fluorane,

[0074] 3-(N - Ethyl - N - isobutylamine)-6 - methyl - 7 - anilino fluorane, and / or

[0075] 3 - Dipentylamine - 6 - methyl - 7 - anilino fluorane.

[0076] The color former can be used either as a single substance or as an arbitrary mixture of two or more color formers, provided that the desired application-technical properties of the recording material according to the invention are not impaired.

[0077] The color former is preferably present in an amount of from about 5 to about 30% by weight, particularly preferably in an amount of from about 8 to about 20% by weight, based on the total solids content of the thermosensitive layer.

[0078] In order to control specific application-technical properties, it can be advantageous for at least two compounds of formula (I) to be present as color developers in the thermosensitive layer.

[0079] Likewise, in addition to the compounds of formula (I), one or more further (bi)phenolic or non-phenolic color developers can be present in the thermosensitive color layer.

[0080] In addition to at least one color former and at least one color developer, one or more sensitizers (also referred to as thermal solvents) can be present in the thermosensitive color layer, the advantage of the sensitizer being that it is easier to control the thermal printing sensitivity.

[0081] As sensitizers, crystalline substances are generally advantageously considered which have a melting point between about 90 and about 150 °C and dissolve the color-forming components (color former and color developer) in the molten state without interfering with the formation of the colored complex.

[0082] Preferably, the sensitizer is a fatty acid amide such as stearamide, behenamide or palmitamide, an ethylene-bis-fatty acid amide such as N,N'-ethylene-bis-stearamide or N,N'-ethylene-bis-oleamide, a fatty acid alkanolamide such as N-(hydroxymethyl)stearamide, N-hydroxymethylpalmitamide or hydroxyethylstearamide, a wax such as polyethylene wax or montan wax, a carboxylic acid ester such as dimethyl terephthalate, dibenzyl terephthalate, benzyl-4-benzyloxybenzoate, bis-(4-methylbenzyl)oxalate, bis-(4-chlorobenzyl)oxalate or bis-(4-benzyl)oxalate, an aromatic ether such as 1,2-diphenoxyethane, 1,2-bis-(3-methylphenoxy)ethane, 2-benzyloxynaphthalene or 1,4-diethoxynaphthalene, an aromatic sulfone such as diphenyl sulfone, and / or an aromatic sulfonamide such as benzenesulfonanilide or N-benzyl-4-toluenesulfonamide or an aromatic hydrocarbon such as 4-benzylbiphenyl.

[0083] The sensitizer is preferably present in an amount of from about 10 to about 40% by weight, particularly preferably in an amount of from about 15 to about 25% by weight, based on the total solids content of the thermosensitive layer.

[0084] In another preferred embodiment, in addition to the color former, the phenol-free color developer and the sensitizer, at least one stabilizer (anti-aging agent) is optionally present in the thermosensitive color layer.

[0085] The stabilizer is preferably a sterically hindered phenol, particularly preferably 1,1,3-tris-(2-methyl-4-hydroxy-5-cyclohexyl-phenyl)-butane, 1,1,3-tris-(2-methyl-4-hydroxy-5-tert-butylphenyl)-butane, 1,1-bis-(2-methyl-4-hydroxy-5-tert-butyl-phenyl)-butane.

[0086] As the stabilizer in the recording material according to the present invention, a urea-carbamate compound of the general formula (II) (commercially available product UU), or an ether derived from 4,4'-dihydroxydiphenyl sulfone, such as 4-benzyloxy-4'-(2-methylglycidyloxy)-diphenyl sulfone (trade name Nippon Soda Co., Ltd.), or an oligoether of the general formula (III) (trade name Nippon Soda Co., Ltd.) can also be used.

[0087]

[0088] Particularly preferred is the urea-carbamate compound of the general formula (II).

[0089] The stabilizer is preferably present in an amount of 0.2 to 0.5 parts by weight, based on 1 part by weight of the color former of at least one phenol-free compound of formula (I).

[0090] In another preferred embodiment, at least one binder is present in the thermosensitive color layer. The binder is preferably water-soluble starch, starch derivatives, starch-based bio-latexes of the type, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, partially or fully saponified polyvinyl alcohol, chemically modified polyvinyl alcohol or styrene maleic anhydride copolymers, styrene butadiene copolymers, acrylamide-(meth)acrylate copolymers, acrylamide-acrylate-methacrylate terpolymers, polyacrylates, poly(meth)acrylates, acrylate-butadiene copolymers, polyvinyl acetate and / or acrylonitrile-butadiene copolymers.

[0091] In another preferred embodiment, at least one release agent (anti-sticking agent) or lubricant is present in the thermosensitive color layer. These agents are preferably metal salts of fatty acids, such as zinc stearate or calcium stearate, or also behenates, synthetic waxes, such as in the form of fatty acid amides, such as stearic acid amide and behenic acid amide, fatty acid alkanolamides, such as stearic acid hydroxymethylamide, paraffins of different melting points, ester waxes of different molecular weights, propylene waxes of different hardnesses, ethylene waxes, and / or natural waxes, such as carnauba wax or montan wax.

[0092] The release agent is preferably present in an amount of from about 1 to about 10% by weight, particularly preferably in an amount of from about 3 to about 6% by weight, based on the total solids content of the thermosensitive layer.

[0093] In another preferred embodiment, the thermosensitive color-forming layer contains a pigment. The advantage of using a pigment is in particular that the pigment can fix the chemical melt generated during the thermal printing process on its surface. The surface whiteness and opacity of the thermosensitive color-forming layer and its printability with conventional printing inks can also be controlled by the pigment. Finally, for relatively expensive coloring functional chemicals, for example, the pigment has a "bulking agent function".

[0094] Particularly suitable pigments are inorganic pigments of synthetic and natural origin, preferably clay, precipitated or natural calcium carbonate, aluminum oxide, aluminum hydroxide, silica, precipitated or fumed silica (e.g. type), diatomaceous earth, magnesium carbonate, talc, and organic pigments, such as hollow pigments with a styrene / acrylic ester copolymer wall or urea / formaldehyde condensation polymers. They can be used alone or in any mixture.

[0095] The pigment is preferably present in an amount of from about 20 to about 50% by weight, particularly preferably in an amount of from about 30 to about 40% by weight, based on the total solids content of the thermosensitive layer.

[0096] In order to control the surface whiteness of the thermosensitive recording material according to the invention, a brightening agent can be introduced into the thermosensitive color-forming layer. The brightening agent is preferably stilbene.

[0097] In order to improve certain coating technical properties, in some cases it is preferred to add other components, especially rheology aids, such as thickeners and / or surfactants, to the components of the thermosensitive recording material according to the invention.

[0098] (Dry) The coating weight per unit area of the thermosensitive layer is preferably from about 1 to about 10 g / m 2 , more preferably from about 3 to about 6 g / m 2 .

[0099] In a particularly preferred embodiment, the thermosensitive recording material is the thermosensitive recording material according to claim 9, wherein a dye of the fluoran type is used as the color former, and a sensitizer selected from fatty acid amides, aromatic sulfones and / or aromatic ethers is additionally present. In the said preferred embodiment, it is also advantageous that, based on 1 part by weight of the color former, there is present from about 1.5 to about 4 parts by weight of the phenol-free developer according to claim 1.

[0100] The preferred embodiments described in connection with the compounds of formula (I) are also applicable to the thermosensitive recording materials according to the invention.

[0101] The thermosensitive recording material according to the present invention can be obtained by known preparation methods.

[0102] However, preferably, the recording material according to the present invention is obtained by a method in which an aqueous suspension of a starting material containing a thermosensitive color-forming layer is applied to a carrier substrate and dried, wherein the aqueous application suspension has a solids content of about 20 to about 75% by weight, preferably about 30 to about 50% by weight, and is applied and dried by a curtain coating method at a coating device running speed of at least about 400 m / min.

[0103] This method is particularly advantageous from an economic point of view.

[0104] If the value of the solids content is below about 20% by weight, the economy deteriorates because a large amount of water must be removed from the coating material by gentle drying in a short time, which has an adverse effect on the coating speed. On the other hand, if the value exceeds 75% by weight, this can only ensure the stability of the coating ink curtain film during the coating process at the cost of increased technical expenditure.

[0105] In the curtain coating method (curtain coating process), a free-falling curtain film of the coating dispersion is formed. By free-falling, the coating dispersion present in the form of a thin film (curtain film) "flows" onto the substrate, thereby applying the coating dispersion to the substrate. DE10196052T1 discloses the use of the curtain coating method to prepare an information recording material, especially a thermosensitive recording material, in which a multi-layer recording layer (maximum speed 200 m / min) is achieved by applying a curtain film composed of a plurality of coating dispersion films onto the substrate.

[0106] Adjusting the coating device running speed to at least about 400 m / min has not only economic advantages but also technical advantages. Preferably, the running speed is at least about 750 m / min, particularly preferably at least about 1000 m / min, and very particularly preferably at least about 1500 m / min. Especially unexpectedly, even at the last-mentioned speed, the obtained thermosensitive recording material is not affected in any way, and the running process is also carried out in an optimal manner even at such a high speed.

[0107] In a preferred embodiment of the method according to the present invention, the degassed aqueous application suspension has a viscosity (Brookfield, 100 revolutions / min, 20 °C) of about 150 to about 800 mPas. If the value is below about 150 mPas or the value exceeds about 800 mPas, it results in insufficient fluidity of the coating material on the coating equipment. Particularly preferably, the viscosity of the degassed aqueous application suspension is about 200 to about 500 mPas.

[0108] In a preferred embodiment, in order to optimize the method, the surface tension of the aqueous coating suspension can be adjusted to about 25 to about 60 mN / m, preferably to about 35 to about 50 mN / m (measured according to the static ring method of Du Noüy, DIN 53914).

[0109] The formation of the heat-sensitive color layer can be carried out online or offline in a separate coating process. The same applies to any subsequent applied layers or intermediate layers that may be present.

[0110] Advantageously, the dry heat-sensitive color layer is subjected to a smoothing measure. Here, it is advantageous to adjust the Bekk smoothness measured according to ISO 5627:1995-03 to about 100 to about 1000 seconds, preferably to about 250 to about 600 seconds.

[0111] The surface roughness (PPS) according to ISO 8791-4:2008-05 is preferably in the range of about 0.50 to about 2.50 μm, particularly preferably in the range of 1.00 to 2.00 μm.

[0112] The preferred embodiments implemented with respect to the compounds of formula (I) also apply to the process according to the invention for preparing the heat-sensitive recording material according to the invention.

[0113] The invention also relates to a heat-sensitive recording material obtainable by the above process.

[0114] The above process is advantageous from an economic point of view and allows a high-speed process of the coating device even at speeds greater than 1500 m / min without affecting the process product, i.e., the heat-sensitive recording material according to the invention. The process can be carried out online or offline, which results in the desired flexibility.

[0115] The heat-sensitive recording material according to the invention preferably contains no phenol and is well-suited for POS (point of sale), label, and / or ticket applications. It is also suitable for the preparation of parking tickets, tickets, admission tickets, lottery tickets, betting slips, etc., which can be directly printed using a thermal method and need to ensure high resistance of the recorded graphics thereon when the lettering comes into contact with hydrophobic substances such as plasticizers, binders, fatty or oily substances, etc.

[0116] It has surprisingly been shown that the use of the developer of formula (I) according to the invention can provide a heat-sensitive recording material that exhibits excellent resistance of the lettering to hydrophobic reagents and achieves good lettering quality (high optical density (o.D.) of the printed image).

[0117] As a comparative developer, a non-phenolic developer of the prior art, i.e., sulfonylurea (Pergafast (PF201), BASF) and the urea derivative Z (N-(2-(3-phenylureido)phenyl)benzenesulfonamide).

[0118] The present invention is explained in detail below by means of non-limiting examples. Examples

[0119] Preparation of the compounds of formula (I) according to the invention.

[0120] Compound I-XXIV (Table 2) was prepared as follows:

[0121] Step A1 – Preparation of the sulfonamide

[0122] To a solution of 20 mmol of aromatic diamine and 20 mmol of pyridine in 125 mL of dichloromethane stirred at 0 °C was added dropwise a solution of 10 mmol of the corresponding sulfonyl chloride in 75 mL of dichloromethane. The reaction solution was stirred at room temperature for 16 h, and then 100 mL of water was added. The organic phase was separated and 250 mL of 5% aqueous sodium hydroxide solution was added. The aqueous phase was washed with 100 mL of dichloromethane and adjusted to neutral by adding 25% hydrochloric acid. After extraction several times with 100 mL of dichloromethane, the combined organic phases were washed with 200 mL of water and dried over magnesium sulfate. After removal of the solvent in vacuo, the sulfonamide remained in solid form. The sulfonamide was used in steps B or C without further purification.

[0123] Simple filtration after adding water to the reaction solution was sufficient to obtain the precursor compounds of IX and XII.

[0124] Step A2 – Preparation of the sulfonamide

[0125] To a solution of 80 mL of aromatic amine and 240 mmol of potassium carbonate in 500 mL of dichloroethane stirred at room temperature was added dropwise a solution of 80 mmol of the corresponding sulfonyl chloride in 150 mL of dichloroethane. The reaction mixture was refluxed for 6 h, and then 300 mL of ethyl acetate and 300 mL of water were added. The aqueous phase was adjusted to acidic by adding 25% hydrochloric acid. Phase separation was carried out. After extraction of the aqueous phase several times with 200 mL of ethyl acetate, the combined organic phases were washed with 200 mL of water and dried over magnesium sulfate. After removal of the solvent in vacuo, the sulfonamide remained in solid form. The sulfonamide was used in step B without further purification.

[0126] Step A3 – Preparation of the sulfonamide

[0127] At 0 °C under stirring and in a protective gas atmosphere, a solution of 25.0 mmol of an aromatic amine in 35 mL of absolute THF was added dropwise to a solution of 27.5 mmol of sodium hydride (60% in oil) in 25 mL of absolute THF. After stirring in two stages for 2 h at room temperature, a solution of 25.0 mmol of the corresponding sulfonyl chloride in 10 mL of absolute THF was added dropwise at 0 °C under stirring. The reaction solution was stirred at room temperature for 40 h, and then 100 mL of water and 100 mL of dichloromethane were added. The aqueous phase was adjusted to basicity by adding 5% aqueous sodium hydroxide solution. Phase separation was carried out. The aqueous phase was washed with 100 mL of dichloromethane and adjusted to neutrality by adding 25% hydrochloric acid. After extraction several times with 100 mL of dichloromethane, the combined organic phases were washed with 200 mL of water and dried over magnesium sulfate. After removal of the solvent in vacuo, the sulfonamide remained in solid form. The sulfonamide was used in

[0128] Step B without further purification.

[0129] Step B - Reduction of the nitro group to a primary amine

[0130] Under stirring at room temperature, 28.0 mmol (product from Step A1) or 56.0 mmol (product from Step A2 / A3) of SnCl2·2H2O was added to a solution of 8.0 mmol of the product from Step A1 / A2 / A3 in 140 mL of ethyl acetate. The reaction solution was refluxed. The progress of the reaction was monitored by thin layer chromatography (eluent: cyclohexane / ethyl acetate 1:1). After the reaction was complete (about 2 - 3 h), it was diluted with 70 mL of ethyl acetate, 10% aqueous potassium carbonate solution was added, and it was stirred at room temperature for 30 min. The Sn compound was filtered off and the aqueous and organic phases were separated in the filtrate. The organic phase was washed with 100 ml (2x) of saturated sodium chloride aqueous solution and dried over magnesium sulfate. After removal of the solvent in vacuo, purification was carried out by recrystallization from dichloromethane and a few drops of n-hexane.

[0131] Step C1 - Preparation of the sulfonylurea compound

[0132] At room temperature under stirring, a solution of 7.0 mmol of the product from Step A1 in dichloromethane (20 to 40 mL) (in the case of poor solubility, additionally in 10 mL of acetonitrile) was added dropwise to a solution of 7.0 mmol of the corresponding sulfonyl isocyanate in 10 mL of dichloromethane. The reaction was monitored by thin layer chromatography (eluent: cyclohexane / ethyl acetate 1:1). After the reaction was complete, the precipitated product was filtered off, washed with dichloromethane and dried in vacuo. In some cases, the reaction solution was concentrated in vacuo and crystallization was initiated by adding a few drops of n-hexane.

[0133] Step C2 - Preparation of the sulfonylurea compound

[0134] While stirring, a solution of 4.2 mmol of the product from step B in DMF (16 mL) was added dropwise to a solution of 8.4 mmol of the corresponding sulfonyl isocyanate in DMF (5 to 10 mL). The reaction was monitored by thin-layer chromatography (eluent: cyclohexane / ethyl acetate 1:1). After the reaction was completed, the reaction solution was diluted with 100 mL of ethyl acetate, washed with 100 mL (2x) of saturated aqueous sodium chloride solution, and then washed with 100 mL of water. After removing the solvent in vacuo, purification was carried out by recrystallization from dichloromethane and a few drops of n-hexane.

[0135] Compounds I to XIX (Table 2) were prepared starting from the corresponding phenylenediamines according to the general procedures of steps A1 and C1.

[0136] Compound XX (Table 2) was prepared starting from 2,6-dinitroaniline, which was first converted to 1,2-diamino-3-nitrobenzene (Reaction Scheme 3, V. Milata, J. Saloň, Org. Prep. Proceed. Int., 31(3), 347 (1999)), and finally converted to the final product according to the general procedures of steps A1, B, and C2.

[0137] Compounds XXI to XXIV (Table 2) were prepared starting from 2,4-dinitroaniline (XXI and XXII), 4-nitro-1,2-phenylenediamine (XXIII), and 2,6-dinitroaniline (XXIV) according to the general procedures of steps A1 (XXIII), A2 (XXI and XXII), A3 (XXIV), B (XXI - XXIV), and C2 (XXI - XXIV).

[0138] The starting compounds are commercially available.

[0139] Table 2: Summary of the selected compounds of formula (I)

[0140] Y <![CDATA[Ar 1 > <![CDATA[Ar 2 > m n I 1,2-Phenylene <![CDATA[C6H5]]> <![CDATA[C6H5]]> 1 1 II 1,2-Phenylene <![CDATA[C6H5]]> <![CDATA[4-CH3-C6H4]]> 1 1 III 1,2-Phenylene <![CDATA[4-CH3-C6H4]]> <![CDATA[C6H5]]> 1 1 IV 1,2-Phenylene <![CDATA[4-CH3-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 1 V 1,2-Phenylene <![CDATA[4-(tert-C4H9)-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 1 VI 1,2-Phenylene <![CDATA[2,4,6-TriCH3-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 1 VII 1,2-Phenylene <![CDATA[4-OCH3-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 1 VIII 1,2-Phenylene <![CDATA[4-Cl-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 1 IX 1,2-Phenylene <![CDATA[4-(NH-CO-CH3)-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 1 X 1,2-Phenylene <![CDATA[4-NO2-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 1 XI 1,2-Phenylene <![CDATA[2-(CO2CH3)-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 1 XII 1,2-Phenylene 2-Naphthyl <![CDATA[4-CH3-C6H4]]> 1 1 XIII 1,2-Phenylene <![CDATA[C6H5-CH2]]> <![CDATA[4-CH3-C6H4]]> 1 1 XIV 1,3-Phenylene* <![CDATA[C6H5]]> <![CDATA[4-CH3-C6H4]]> 1 1 XV 1,3-Phenylene* <![CDATA[4-CH3-C6H4]]> <![CDATA[C6H5]]> 1 1 XVI 1,3-Phenylene* <![CDATA[4-CH3-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 1 XVII 1,4-Phenylene* <![CDATA[C6H5]]> <![CDATA[4-CH3-C6H4]]> 1 1 XVIII 1,4-Phenylene* <![CDATA[4-CH3-C6H4]]> <![CDATA[C6H5]]> 1 1 XIX 1,4-Phenylene* <![CDATA[4-CH3-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 1 XX Benzene-1,2,3-triyl <![CDATA[4-CH3-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 2 XXI Benzene-1,2,4-triyl <![CDATA[4-CH3-C6H4]]> <![CDATA[C6H5]]> 1 2 XXII Benzene-1,2,4-triyl <![CDATA[4-CH3-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 2 XXIII Benzene-1,2,5-triyl <![CDATA[4-CH3-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 2 XXIV Benzene-1,2,6-triyl <![CDATA[4-CH3-C6H4]]> <![CDATA[4-CH3-C6H4]]> 1 2

[0141] *: Comparative example

[0142] Analysis data:

[0143] I, C 19 H 17 N3O5S2, M = 431.5, N-((2-(phenylsulfonylamino)phenyl)carbamoyl)benzenesulfonamide MS(ESI): m / z(%) = 430.0(14) [M - H] - , 273.0(100) [M - H - Ar 2 SO2NH2] - , 247.0(15) [M - H - Ar2 SO2NCO] - 。

[0144] *H-NMR(500 MHz, DMSO-d6): δ(ppm) = 11.66(1H, s), 9.60(1H, s), 8.57(1H, s), 8.01 - 7.99(2H, m), 7.86(1H, dd, J = 8.3, 1.3 Hz), 7.73 - 7.69(1H, m), 7.68 - 7.62(5H, m), 7.56 - 7.53(2H, m), 7.16 - 7.12(1H, m), 6.80(1H, ddd, J = 8.9, 7.9, 1.4 Hz), 6.39(1H, dd, J = 7.9, 1.1 Hz).

[0145] 13 C-NMR(126 MHz, DMSO-d6): δ(ppm) = 149.12(NH C ONH), 139.78, 138.87, 135.56, 133.39, 133.01, 129.10, 129.03, 127.82, 127.27, 127.23, 127.08, 125.28, 123.15, 120.75.

[0146] II, C 20 H 19 N3O5S2, M = 445.5, N-((2-(phenylsulfonamido)phenyl)carbamoyl)toluene sulfonamide

[0147] MS(ESI): m / z(%) = 444.0(23)[M - H] - , 273.0(100)[M - H - Ar 2 SO2NH2] - , 247.1(21)[M - H - Ar 2 SO2NCO] - 。

[0148] 1H-NMR (500 MHz, DMSO-d6): δ (ppm) = 11.58 (1H, s), 9.60 (1H, s), 8.56 (1H, s), 7.89 - 7.86 (3H, m), 7.68 - 7.66 (2H, m), 7.65 - 7.62 (1H, m), 7.56 - 7.53 (2H, m), 7.44 - 7.43 (2H, m), 7.16 - 7.12 (1H, m), 6.79 (1H, ddd, J = 8.9, 7.7, 1.4 Hz), 6.38 (1H, dd, J = 7.9, 1.3 Hz), 2.39 (3H, s).

[0149] 13 C-NMR (126 MHz, DMSO-d6): δ (ppm) = 149.16 (NH C ONH), 143.93, 138.90, 136.95, 135.67, 133.02, 129.52, 129.05, 127.84, 127.37, 127.25, 127.10, 125.22, 123.08, 120.68, 21.00( C H3).

[0150] III, C 20 H 19 N3O5S2, M = 445.5, N-(2-(3-(phenylsulfonyl)ureido)phenyl)toluene sulfonamide

[0151] MS (ESI): m / z (%) = 444.0 (17) [M - H] - , 287.0 (100) [M - H - Ar 2 SO2NH2] - , 261.1 (7) [M - H - Ar 2 SO2NCO] - .

[0152] 1 H-NMR (500 MHz, DMSO-d6): δ (ppm) = 11.66 (1H, s), 9.51 (1H, s), 8.56 (1H, s), 8.01 - 7.99 (2H, m), 7.85 (1H, dd, J = 8.3, 1.4 Hz), 7.73 - 7.69 (1H, m), 7.66 - 7.63 (2H, m), 7.56 - 7.54 (2H, m), 7.35 - 7.33 (2H, m), 7.15 - 7.11 (1H, m), 6.81 (1H, ddd, 9.1, 7.7, 1.4 Hz), 6.43 - 6.42 (1H, m), 2.36 (3H, s).

[0153] 13 C-NMR (126 MHz, DMSO-d6): δ (ppm) = 149.13 (NH C ONH), 143.34, 139.80, 136.07, 135.48, 133.38, 129.47, 129.09, 127.70, 127.26, 127.18, 127.13, 125.43, 123.16, 120.73, 20.96( C H3).

[0154] IV, C 21 H 21 N3O5S2, M = 459.5, N-((2-(Tosylamino)phenyl)carbamoyl)tosylamide

[0155] MS (ESI): m / z (%) = 458.1 (26) [M-H] - , 287.0 (100) [M-H-Ar 2 SO2NH2] - , 261.0 (10) [M-H-Ar 2 SO2NCO] - .

[0156] 1 H-NMR (500 MHz, DMS0-d6): δ (ppm) = 11.58 (1H, s), 9.50 (1H, s), 8.55 (1H, s), 7.89 - 7.85 (3H, m), 7.56 - 7.54 (2H, m), 7.44 - 7.42 (2H, m), 7.35 - 7.33 (2H, m), 7.15 - 7.11 (1H, m), 6.80 (1H, ddd, J = 9.0, 7.7, 1.4 Hz), 6.43 - 6.41 (1H, m), 2.39 (3H, s), 2.36 (3H, s).

[0157] 13 C-NMR (126 MHz, DMSO-d6): δ (ppm) = 149.15 (NH C ONH), 143.88, 143.33, 136.98, 136.11, 135.59, 129.49, 129.45, 127.70, 127.36, 127.19, 127.15, 125.37, 123.07, 120.65, 20.98( C H3), 20.94( C H3).

[0158] V, C 24H 27 N3O5S2, M = 501.6, N-(2-(3-Toluenesulfonylureido)phenyl)-4-tert-butylbenzenesulfonamide

[0159] MS(ESI): m / z(%) = 500.1(56) [M-H] - , 329.1(100) [M-H-Ar 2 SO2NH2] - 。

[0160] 1 H-NMR(500MHz, DMSO-d6): δ(ppm) = 11.57(1H, s), 9.53(1H, s), 8.55(1H, s), 7.89 - 7.87(2H, m), 7.86 - 7.85(1H, m), 7.62 - 7.60(2H, m), 7.58 - 7.56(2H, m), 7.44 - 7.42(2H, m), 7.14 - 7.11(1H, m), 6.80 - 6.77(1H, m), 6.42 - 6.40(1H, m), 2.39(3H, s), 1.28(9H, s)。

[0161] 13 C-NMR(126MHz, DMSO-d6): δ(ppm) = 156.10, 149.16(NH C ONH), 143.89, 136.96, 136.15, 135.48, 129.51, 127.66, 127.35, 127.03, 127.03, 125.84, 125.44, 123.05, 120.68, 34.83( C (CH3)3), 30.71(C( C H3)3), 21.00( C H3)。

[0162] VI, C 23 H 25 N3O5S2, M = 487.6, N-(2-(3-Toluenesulfonylureido)phenyl)-2,4,6-trimethylbenzenesulfonamide

[0163] MS(ESI): m / z(%) = 486.1(37) [M-H] - , 315.1(100) [M-H-Ar 2 SO2NH2] - , 289.1(18) [M-H-Ar 2 SO2NCO] - 。

[0164] 1 1H-NMR (500 MHz, DMSO-d6): δ (ppm) = 11.66 (1H, s), 9.26 (1H, s), 8.62 (1H, s), 7.89 - 7.87 (3H, m), 7.44 - 7.42 (2H, m), 7.18 - 7.14 (1H, m), 6.98 (2H, s), 6.77 (1H, ddd, J = 9.0, 7.7, 1.4 Hz), 6.26 (1H, dd, J = 7.9, 1.3 Hz), 2.39 (3H, s), 2.29 (6H, s), 2.24 (3H, s).

[0165] 13 13C-NMR (126 MHz, DMSO-d6): δ (ppm) = 149.26 (NH C ONH), 143.87, 142.02, 138.89, 136.96, 136.06, 133.30, 131.54, 129.48, 127.99, 127.83, 127.35, 124.76, 123.09, 120.55, 22.42 (2x C H3), 20.98 ( C H3), 20.36 ( C H3).

[0166] VII, C 21 H 21 C9H11N3O6S2, M = 475.5, N-(2-(3-Toluenesulfonylureido)phenyl)-4-methoxybenzenesulfonamide

[0167] MS (ESI): m / z (%) = 474.1 (28) [M - H] - , 303.0 (100) [M - H - Ar 2 SO2NH2] - .

[0168] 1 1H-NMR (500 MHz, DMSO-d6): δ (ppm) = 11.59 (1H, s), 9.42 (1H, s), 8.56 (1H, s), 7.89 - 7.85 (3H, m), 7.60 - 7.58 (2H, m), 7.44 - 7.42 (2H, m), 7.15 - 7.12 (1H, m), 7.07 - 7.05 (2H, m), 6.82 (1H, ddd, J = 8.7, 7.7, 1.0 Hz), 6.43 (1H, dd, J = 7.9, 1.1 Hz), 3.82 (3H, s), 2.39 (3H, s).

[0169] 1313C-NMR(126MHz, DMSO-d6): δ(ppm) = 162.53, 149.16 (NH C ONH), 143.90, 136.96, 135.64, 130.47, 129.50, 129.34, 127.70, 127.34, 127.30, 125.46, 123.07, 120.58, 114.17, 55.60 (O C H3), 20.99 ( C H3).

[0170] VIII, C 20 H 18 ClN3O5S2, M = 480.0, N-(2-(3-Toluenesulfonylureido)phenyl)-4-chlorobenzenesulfonamide

[0171] MS(ESI): m / z(%) = 478.0 (29) [M-H] - , 307.0 (100) [M-H-Ar 2 SO2NH2] - , 281.0 (49) [M-H-Ar 2 SO2NCO] - .

[0172] 1 1H-NMR(500MHz, DMSO-d6): δ(ppm) = 11.56 (1H, s), 9.70 (1H, s), 8.55 (1H, s), 7.88 - 7.86 (3H, m), 7.67 - 7.65 (2H, m), 7.63 - 7.61 (2H, m), 7.44 - 7.43 (2H, m), 7.18 - 7.14 (1H, m), 6.84 (1H, ddd, J = 9.2, 7.9, 1.4Hz), 6.44 (1H, dd, J = 7.9, 1.5Hz), 2.39 (3H, s).

[0173] 13 13C-NMR(126MHz, DMSO-6): δ(ppm) = 149.13 (NH C ONH), 143.93, 137.95, 137.77, 136.91, 135.65, 129.52, 129.24, 129.04, 128.00, 127.35, 127.28, 124.97, 123.26, 120.79, 21.00 ( C H3).

[0174] IX, C 22 H 22N4O6S2, M = 502.6, N-(4-(N-(2-(3-Toluenesulfonylureido)phenyl)aminosulfonyl)phenyl)acetamide

[0175] MS(ESI): m / z(%) = 501.0(32)[M-H] - , 330.1(100)[M-H-Ar 2 SO2NH2] - 。

[0176] 1 H-NMR(500MHz, DMSO-d6): δ(ppm) = 11.60(1H, s), 10.30(1H, s), 9.45(1H, s), 8.56(1H, s), 7.89 - 7.86(3H, m), 7.75 - 7.73(2H, m), 7.60 - 7.57(2H, m), 7.44 - 7.42(2H, m), 7.15 - 7.12(1H, m), 6.81(1H, ddd, J = 9.0, 7.6, 1.4Hz), 6.40(1H, dd, J = 7.9, 1.4Hz), 2.39(3H, s), 2.09(3H, s).

[0177] 13 C-NMR(126MHz, DMSO-d6): δ(ppm) = 169.01(NH C OCH3), 149.19(NH C ONH), 143.91, 143.26, 136.96, 135.69, 132.36, 129.51, 128.38, 127.73, 127.35, 127.28, 125.41, 123.08, 120.59, 118.34, 24.11( C H3), 21.00( C H3).

[0178] X, C 20 H 18 N4O7S2, M = 490.5, N-((2-(4-Nitrophenylsulfonamido)phenyl)carbamoyl)toluenesulfonamide

[0179] MS(ESI): m / z(%) = 489.0(31)[M-H] - , 318.0(55)[M-H-Ar 2 SO2NH2] - , 292.0(100)[M-H-Ar 2 SO2NCO] - 。

[0180] 1 1H-NMR (500 MHz, DMSO-d6): δ (ppm) = 11.51 (1H, s), 9.97 (1H, s), 8.52 (1H, s), 8.40 - 8.37 (2H, m), 7.92 - 7.89 (2H, m), 7.87 - 7.84 (3H, m), 7.44 - 7.42 (2H, m), 7.20 - 7.16 (1H, m), 6.85 (1H, ddd, J = 8.9, 7.7, 1.4 Hz), 6.48 (1H, dd, J = 7.9, 1.3 Hz), 2.39 (3H, s).

[0181] 13 13C-NMR (126 MHz, DMSO-d6): δ (ppm) = 149.88, 149.13 (NH C ONH), 144.49, 143.96, 136.89, 135.60, 129.52, 128.67, 128.24, 127.50, 127.33, 124.71, 124.47, 123.50, 121.08, 21.00 ( C H3).

[0182] XI, C 22 H 21 N3O7S2, M = 503.5, Methyl 2-(N-(2-(3-toluenesulfonylureido)phenyl)sulfamoyl)benzoate

[0183] MS (ESI): m / z (%) = 502.1 (32) [M - H] - , 331.0 (100) [M - H - Ar 2 SO2NH2] - , 305.0 (31) [M - H - Ar 2 SO2NCO] - .

[0184] 1 1H-NMR (500 MHz, DMSO-d6): δ (ppm) = 11.53 (1H, s), 9.21 (1H, s), 8.53 (1H, s), 7.88 - 7.86 (2H, m), 7.82 - 7.81 (1H, m), 7.73 - 7.72 (2H, m), 7.67 - 7.65 (2H, m), 7.44 - 7.42 (2H, m), 7.18 - 7.15 (1H, m), 6.85 - 6.82 (1H, m), 6.55 - 6.54 (1H, m), 3.72 (3H, s), 2.39 (3H, s).

[0185] 13 13C-NMR(126 MHz, DMSO-d6): δ (ppm) = 167.35( C OOCH3), 149.29 (NH C ONH), 143.90, 136.93, 136.57, 135.40, 133.17, 132.03, 130.94, 129.49, 129.13, 129.11, 127.91, 127.42, 127.34, 125.39, 123.43, 121.21, 52.87 (COO C H3), 20.98( C H3).

[0186] XII, C 24 H 21 N3O5S2, M = 495.6, N-(2-(3-Toluenesulfonylureido)phenyl)naphthalene-2-sulfonamide

[0187] MS (ESI): m / z (%) = 494.1 (24) [M-H] - , 323.0 (100) [M-H-Ar 2 SO2NH2] - , 297.0 (26) [M-H-Ar 2 SO2NCO] - .

[0188] 1 1H-NMR (500 MHz, DMSO-d6): δ (ppm) = 11.64 (1H, s), 9.73 (1H, s), 8.64 (1H, s), 8.27 (1H, d, J = 1.4 Hz), 8.13 - 8.12 (1H, m), 8.08 - 8.06 (1H, m), 8.04 - 8.02 (1H, m), 7.90 - 7.89 (2H, m), 7.89 (1H, dd, J = 8.3, 1.3 Hz), 7.80 (1H, dd, J = 8.7, 1.9 Hz), 7.71 - 7.68 (1H, m), 7.65 - 7.61 (1H, m), 7.45 - 7.43 (2H, m), 7.12 - 7.09 (1H, m), 6.71 - 6.68 (1H, m), 6.37 - 6.36 (1H, m), 2.39 (3H, s).

[0189] 13 13C-NMR (126 MHz, DMSO-d6): δ (ppm) = 149.19 (NH CONH), 143.92, 136.96, 135.95, 135.74, 134.29, 131.43, 129.52, 129.26, 129.19, 128.94, 128.34, 127.84, 127.81, 127.61, 127.37, 127.22, 125.21, 123.09, 122.45, 120.67, 20.99( C H3).

[0190] XIII, C 21 H 21 N3O5S2, M = 459.5, N-((2-(Benzylsulfonamido)phenyl)carbamoyl)toluene sulfonamide

[0191] MS(ESI): m / z(%) = 458.0(16) [M - H] - , 287.0(100) [M - H - Ar 2 SO2NH2] - , 261.1(13) [M - H - Ar 2 SO2NCO] - .

[0192] 1 H-NMR(500 MHz, DMSO-d6): δ(ppm) = 11.47(1H, s), 9.25(1H, s), 8.40(1H, s), 7.86 - 7.84(2H, m), 7.81(1H, dd, J = 8.4, 1.4 Hz), 7.39 - 7.34(8H, m), 7.25 - 7.21(1H, m), 7.10(1H, ddd, J = 9.0, 7.6, 1.5 Hz), 4.40(2H, s), 2.36(3H, s).

[0193] 13 C-NMR(126 MHz, DMSO-6): δ(ppm) = 149.33(NH C ONH), 143.87, 136.93, 134.39, 130.83, 129.46, 129.06, 128.33, 128.16, 127.52, 127.33, 127.33, 126.50, 123.97, 121.66, 57.25( C H2), 20.98( C H3).

[0194] XIV, C 20 H 19N3O5S2, M = 445.5, N-((3-(phenylsulfonamido)phenyl)carbamoyl)toluene sulfonamide

[0195] MS(ESI): m / z(%) = 444.0(100)[M-H] - , 272.9(7)[M-H-Ar 2 SO2NH2] - 。

[0196] 1 H-NMR(500MHz, DMSO-d6): δ(ppm) = 10.55(1H, s), 10.24(1H, s), 8.83(1H, s), 7.86 - 7.84(2H, m), 7.76 - 7.74(2H, m), 7.59 - 7.56(1H, m), 7.52 - 7.49(2H, m), 7.43 - 7.41(2H, m), 7.24 - 7.23(1H, m), 7.10 - 7.07(1H, m), 6.97(1H, ddd, J = 8.2, 2.0, 0.8Hz), 6.76(1H, ddd, J = 8.1, 2.1, 0.9Hz), 2.39(3H, s)。

[0197] 13 C-NMR(126MHz, DMSO-d6): δ(ppm) = 149.05(NH C ONH), 143.80, 139.46, 138.70, 138.19, 137.01, 132.79, 129.39, 129.39, 129.11, 127.45, 126.58, 114.42, 114.34, 110.23, 20.98( C H3)。

[0198] XV, C 20 H 19 N3O5S2, M = 445.5, N-(3-(3-(phenylsulfonyl)ureido)phenyl)toluene sulfonamide

[0199] MS(ESI): m / z(%) = 444.0(100)[M-H] - , 287.0(6)[M-H-Ar 2 SO2NH2] - 。

[0200] 1H-NMR(500MHz, DMSO-d6): δ(ppm) = 10.44(1H, s), 10.17(1H, s), 8.87(1H, s), 7.99 - 7.97(2H, m), 7.71 - 7.68(1H, m), 7.64 - 7.61(4H, m), 7.30 - 7.28(2H, m), 7.24 - 7.23(1H, m), 7.10 - 7.07(1H, m), 6.97(1H, ddd, J = 8.2, 2.1, 0.9Hz), 6.76(1H, ddd, J = 8.1, 2.1, 0.9Hz), 2.30(3H, s).

[0201] 13 C-NMR(126MHz, DMSO-d6): δ(ppm) = 149.03(NH C ONH), 143.16, 139.90, 138.64, 138.34, 136.61, 133.28, 129.54, 129.36, 128.97, 127.37, 126.66, 114.27, 114.22, 110.04, 20.87( C H3).

[0202] XVI, C 21 H 21 N3O5S2, M = 459.5, N-((3-(Toluenesulfonamido)phenyl)carbamoyl)toluenesulfonamide

[0203] MS(ESI): m / z(%) = 458.1(100)[M - H] - , 287.0(4)[M - H - Ar 2 SO2NH2] - .

[0204] 1 H-NMR(500MHz, DMSO-d6): δ(ppm) = 10.53(1H, s), 10.17(1H, s), 8.82(1H, s), 7.86 - 7.85(2H, m), 7.65 - 7.63(2H, m), 7.42 - 7.41(2H, m), 7.30 - 7.28(2H, m), 7.24 - 7.24(1H, m), 7.10 - 7.06(1H, m), 6.97 - 6.95(1H, m), 6.77 - 6.75(1H, m), 2.38(3H, s), 2.30(3H, s).

[0205] 13 C-NMR(126MHz, DMSO-d6): δ(ppm) = 149.05(NHC ONH), 143.80, 143.15, 138.68, 138.35, 137.03, 136.62, 129.54, 129.39, 129.36, 127.46, 126.67, 114.22, 114.17, 109.98, 20.99( C H3), 20.87( C H3)。

[0206] XVII, C 20 H 19 N3O5S2, M = 445.5, N-((4-(phenylsulfonamido)phenyl)carbamoyl)toluene sulfonamide

[0207] MS(ESI): m / z(%) = 444.0(100)[M - H] - , 273.0(5)[M - H - Ar 2 SO2NH2] - 。

[0208] 1 H-NMR(500 MHz, DMSO-d6): δ(ppm) = 10.47(1H, s), 10.05(1H, s), 8.70(1H, s), 7.84 - 7.82(2H, m), 7.70 - 7.68(2H, m), 7.58 - 7.55(1H, m), 7.52 - 7.49(2H, m), 7.40 - 7.39(2H, m), 7.20 - 7.18(2H, m), 6.99 - 6.97(2H, m), 2.37(3H, s)。

[0209] 13 C-NMR(126 MHz, DMSO-d6): δ(ppm) = 149.19(NH C ONH), 143.77, 139.39, 137.06, 134.61, 132.72, 132.72, 129.41, 129.09, 127.41, 126.59, 121.63, 119.83, 20.99( C H3)。

[0210] XVIII, C 20 H 19 N3O5S2, M = 445.5, N-(4-(3-(phenylsulfonyl)ureido)phenyl)toluene sulfonamide

[0211] MS(ESI): m / z(%) = 444.0(100)[M - H] - , 287.0(5)[M - H - Ar2 SO2NH2] - 。

[0212] 1 1H-NMR (500 MHz, DMSO-d6): δ (ppm) = 10.70 (1H, s), 9.98 (1H, s), 8.73 (1H, s), 7.96 - 7.95 (2H, m), 7.69 - 7.66 (1H, m), 7.62 - 7.57 (4H, m), 7.30 - 7.29 (2H, m), 7.20 - 7.18 (2H, m), 7.00 - 6.97 (2H, m), 2.30 (3H, s).

[0213] 13 13C-NMR (126 MHz, DMSO-d6): δ (ppm) = 149.16 (NH C ONH), 143.04, 139.94, 136.56, 134.40, 133.25, 132.96, 129.51, 128.98, 127.31, 126.64, 121.41, 119.91, 20.87( C H3).

[0214] XIX, C 21 H 21 N3O5S2, M = 459.5, N-((4-(Tosylamino)phenyl)carbamoyl)tosylamide

[0215] MS (ESI): m / z (%) = 458.1 (100) [M - H] - , 287.1 (4) [M - H - Ar 2 SO2NH2] - 。

[0216] 1 1H-NMR (500 MHz, DMSO-d6): δ (ppm) = 10.55 (1H, s), 9.97 (1H, s), 8.68 (1H, s), 7.84 - 7.82 (2H, m), 7.59 - 7.57 (2H, m), 7.40 - 7.39 (2H, m), 7.30 - 7.28 (2H, m), 7.20 - 7.17 (2H, m), 7.00 - 6.97 (2H, m), 2.37 (3H, s), 2.30 (3H, s).

[0217] 13 13C-NMR (126 MHz, DMSO-d6): δ (ppm) = 149.17 (NH CONH), 143.75, 143.03, 137.07, 136.56, 134.44, 132.91, 129.51, 129.39, 127.39, 126.63, 121.42, 119.84, 20.97(CH3), 20.86( C H3).

[0218] XX, C 29 H 29 N5O8S3, M = 671.8, N,N'-(((3-Toluenesulfonylamino-1,2-phenylene)bis(imino))bis(carbonyl))bis(toluenesulfonamide)

[0219] MS(ESI): m / z(%) = 670.0(21)[M - H] - , 499.0(100)[M - H - Ar 2 SO2NH2] - , 302.0(70)[M - H - Ar 2 SO2NCO - Ar 2 SO2NH2] - .

[0220] 1 1H - NMR(500 MHz, DMSO - d6): δ(ppm) = 11.38(1H, s), 11.18(1H, s), 9.47(1H, s), 8.16(1H, s), 7.91(1H, s), 7.91 - 7.89(2H, m), 7.80 - 7.78(2H, m), 7.54 - 7.53(1H, m), 7.49 - 7.47(2H, m), 7.42 - 7.40(4H, m), 7.29 - 7.28(2H, m), 7.00 - 6.97(1H, m), 6.42 - 6.40(1H, m), 2.39(3H, s), 2.38(3H, s), 2.34(3H, s).

[0221] 13 13C - NMR(126 MHz, DMSO - d6): δ(ppm) = 150.34(NH C ONH), 149.01(NH C ONH), 143.91, 143.64, 143.34, 137.20, 136.81, 136.01, 135.71, 133.30, 129.52, 129.50, 129.45, 127.22, 127.20, 126.89, 125.57, 122.98, 119.81, 119.08, 21.01( C H3), 21.01(C H3), 20.95( C H3)。

[0222] XXI, C 27 H 25 N5O8S3, M = 643.7, N,N’-(((4-Toluenesulfonylamino-1,3-phenylene)bis(imino))bis(carbonyl))bis(benzenesulfonamide)

[0223] MS(ESI): m / z(%) = 644.0(79)[M + H] + 。

[0224] 1 1H-NMR(500 MHz, DMSO-d6): δ(ppm) = 11.69(1H, s), 10.62(1H, s), 9.36(1H, s), 8.94(1H, s), 8.53(1H, s), 8.00 - 7.98(2H, m), 7.95 - 7.93(2H, m), 7.91(1H, d, J = 2.5 Hz), 7.74 - 7.59(6H, m), 7.52 - 7.50(2H, m), 7.33 - 7.32(2H, m), 6.86(1H, dd, J = 8.7, 2.5 Hz), 6.23(1H, d, J = 8.7 Hz), 2.35(3H, s)。

[0225] 13 13C-NMR(126 MHz, DMSO-d6): δ(ppm) = 149.05(NH C ONH), 148.98(NH C ONH), 143.35, 139.85, 139.72, 137.58, 136.32, 135.91, 133.45, 133.30, 129.47, 129.13, 129.01, 127.95, 127.35, 127.21, 125.84, 119.89, 113.18, 110.52, 20.98( C H3)。

[0226] XXII, C 29 H 29 N5O8S3, M = 671.8, N,N’-(((4-Toluenesulfonylamino-1,3-phenylene)bis(imino))bis(carbonyl))bis(toluenesulfonamide)

[0227] MS(ESI): m / z(%) = 670.0(15)[M - H] - , 499.0(100)[M - H - Ar 2 SO2NH2]- ,473.0(2)[M-H-Ar 2 SO2NCO] - ,328.0(5)[M-H-2xAr 2 SO2NH2] - 。

[0228] 1 H-NMR(500 MHz, DMSO-d6): δ(ppm) = 11.60(1H, s), 10.69(1H, s), 9.34(1H, s), 9.18(1H, s), 8.55(1H, s), 7.91(1H, d, J = 2.4 Hz), 7.87 - 7.85(2H, m), 7.82 - 7.80(2H, m), 7.51 - 7.50(2H, m), 7.45 - 7.43(2H, m), 7.40 - 7.39(2H, m), 7.32 - 7.31(2H, m), 6.82(1H, dd, J = 8.7, 2.4 Hz), 6.24(1H, d, J = 8.7 Hz), 2.40(3H, s), 2.38(3H, s), 2.35(3H, s).

[0229] 13 C-NMR(126 MHz, DMSO-d6): δ(ppm) = 149.09(NH C ONH), 148.93(NH C ONH), 143.95, 143.76, 143.31, 137.61, 136.99, 136.87, 136.29, 135.91, 129.54, 129.42, 129.42, 127.92, 127.40, 127.38, 127.21, 119.77, 112.96, 110.27, 21.01( C H3), 21.00( C H3), 20.99( C H3).

[0230] XXIII, C 29 H 29 N5O8S3, M = 671.8, N,N'-(((2-Toluenesulfonylamino-1,4-phenylene)bis(imino))bis(carbonyl))bis(toluenesulfonamide)

[0231] MS(ESI): m / z(%) = 670.0(60)[M-H] - ,499.0(100)[M-H-Ar 2 SO2NH2] - .

[0232] 1 H-NMR (500 MHz, DMSO-d6): δ (ppm) = 11.38 (1H, s), 10.47 (1H, s), 9.47 (1H, s), 8.68 (1H, s), 8.33 (1H, s), 7.86 - 7.84 (2H, m), 7.82 - 7.81 (2H, m), 7.62 (1H, d, J = 9.0 Hz), 7.54 - 7.52 (2H, m), 7.43 - 7.41 (4H, m), 7.28 - 7.26 (2H, m), 7.05 (1H, dd, J = 9.0, 2.5 Hz), 6.76 (1H, d, J = 2.5 Hz), 2.39 (3H, s), 2.38 (3H, s), 2.32 (3H, s).

[0233] 13 C NMR (126 MHz, DMSO-d6): δ (ppm) = 149.20 (NH C ONH), 148.86 (NH C ONH), 143.87, 143.78, 143.32, 137.05, 137.02, 135.99, 133.65, 129.88, 129.51, 129.45, 129.37, 127.43, 127.35, 127.02, 126.39, 121.75, 117.81, 117.28, 21.01 ( C H3), 21.01 ( C H3), 20.97 ( C H3).

[0234] XXIV, C 29 H 29 N5O8S3, M = 671.8, N,N'-(((2-Toluenesulfonylamino-1,3-phenylene)bis(imino))bis(carbonyl))bis(toluenesulfonamide)

[0235] MS (ESI): m / z (%) = 670.1 (100) [M - H] - , 499.0 (33) [M - H - Ar 2 SO2NH2] - , 473.0 (29) [M - H - Ar 2 SO2NCO] - , 328.1 (23) [M - H - 2xAr 2 SO2NH2] - , 302.0 (21) [M - H - Ar 2 SO2NCO - Ar 2SO2NH2 - .

[0236] 1 1H-NMR (500 MHz, DMSO-d6): δ (ppm) = 11.22 (2H, s), 8.91 (1H, s), 8.13 (2H, s), 7.84 - 7.82 (4H, m), 7.43 - 7.42 (4H, m), 7.40 - 7.38 (2H, m), 7.37 - 7.35 (2H, m), 7.19 - 7.17 (2H, m), 7.13 - 7.09 (1H, m), 2.39 (6H, s), 2.27 (3H, s).

[0237] 13 13C NMR (126 MHz, DMSO-d6): δ (ppm) = 148.89 (NH C ONH), 143.85, 143.78, 136.95, 136.62, 135.51, 129.44, 129.22, 128.40, 127.28, 126.87, 116.40, 115.44, 20.97 ( C H3), 20.95 ( C H3), 20.95 ( C H3).

[0238] The application of the aqueous coating suspension for forming the thermosensitive color-forming layer of the thermal recording paper is carried out on one side of a 63 g / m 2 synthetic base paper ( FP680) at a laboratory scale with a doctor blade. After drying, a thermal recording paper web is obtained. The coating amount of the thermosensitive color-forming layer is between 3.8 and 4.2 g / m 2 .

[0239] A thermosensitive recording material or thermal paper is prepared with the details provided above, where the following formulation of the aqueous coating suspension is used to form a composite structure on a carrier substrate, and then additional layers, especially a protective layer, are formed in a conventional manner, which will not be elaborated separately here.

[0240] Preparation of the dispersion for the coating suspension (per 1 part by weight)

[0241] The aqueous dispersion A (color former dispersion) is prepared by grinding 20 parts by weight of 3-N-dibutylamino-6-methyl-7-anilinofluoran (ODB-2) and 33 parts by weight of a 15% aqueous solution of Ghosenex TM L-3266 (sulfonated polyvinyl alcohol, Nippon Ghosei) in a bead mill.

[0242] The aqueous dispersion B (developer dispersion) is prepared by grinding 40 parts by weight of the developer together with 66 parts by weight of a 15% aqueous solution of Ghosenex TM L-3266 in a bead mill.

[0243] The aqueous dispersion C (sensitizer dispersion) is prepared by grinding 40 parts by weight of the sensitizer with 33 parts by weight of a 15% aqueous solution of Ghosenex TM L-3266 in a bead mill.

[0244] All dispersions produced by grinding have an average particle size D of 0.80 to 1.20 μm (4,3) . The measurement of the particle size distribution of the dispersion is carried out by laser diffraction using a Coulter LS230 instrument from Beckman Coulter.

[0245] Dispersion D (lubricant dispersion) is a 20% zinc stearate dispersion, which consists of 9 parts by weight of Zn stearate, 1 part by weight of Ghosenex TM L-3266 and 40 parts by weight of water.

[0246] Pigment P is a 72% coating kaolin suspension ( S, BASF).

[0247] The binder consists of a 10% aqueous solution of polyvinyl alcohol (Mowiol 28-99, Kuraray Europe).

[0248] The thermosensitive coating suspension is prepared as follows: Mix 1 part of A, 1 part of B, 1 part of C, 56 parts of D, 146 parts of pigment P and 138 parts of binder solution (all in parts by weight) while stirring, taking into account the introduction order B, D, C, P, A, binder, and make it reach a solid content of about 25% with water.

[0249] The thermosensitive coating suspension thus obtained is used to prepare a composite structure of a paper carrier and a thermal reaction layer.

[0250] Evaluate the thermal recording materials as described below (Tables 3, 4 and 5).

[0251] (1) Dynamic color density:

[0252] Using an Atlantek 200 experimental printer (Atlantek Inc., USA) with a Kyocera print head having 200 dpi and 560 Ohm, a chessboard pattern was thermally printed on paper (a 6 cm wide strip) at an applied voltage of 20.6 V and a maximum pulse width of 0.8 ms with 10 energy levels. The image density (optical density, o.D.) was measured at energy levels of 0.25 and 0.45 mJ / dot using an X-Rite SpectroEye densitometer. The measurement uncertainty of the o.D. value was estimated to be ≤ 2%.

[0253] (2) Static color density (starting temperature):

[0254] With a squeezing pressure of 0.2 kg / cm 2 and a contact time of 5 seconds, a series of thermally controlled metal stamps heated to different temperatures were printed on a recording paper web (thermal testing machine TP 3000QM, Maschinenfabrik Hans Rychiger AG, Steffisburg, Switzerland). The image density (optical density) of the images thus produced was measured using an X-Rite SpectroEye densitometer.

[0255] The static starting point is defined as the lowest temperature at which an optical density of 0.2 is reached. The accuracy of the measurement method is ≤ ±0.5 °C.

[0256] (3) Resistance test of printed images:

[0257] a) Plasticizer resistance:

[0258] A sample of thermal recording paper on which dynamic recording was performed according to the method of (1) was brought into contact with a plasticizer-containing cling film (a PVC film with 20 to 25% dioctyl adipate), while avoiding wrinkles and air entrainment, wound into a roll and stored for 16 hours. One sample was stored at room temperature (20 to 22 °C), and the second sample was stored at 40 °C. After removing the film, the image density (o.D.) was measured and correlated with the corresponding image density value before the action of the plasticizer according to Equation (Equation 1).

[0259] c) Adhesive resistance:

[0260] One transparent Tesa self-adhesive tape was adhered to a sample of thermal recording paper on which dynamic recording was performed according to the method of (1) strips of crystal-clear, #57315) and strips of Tesa packaging tape (#04204) separated therefrom, while avoiding wrinkles and air entrainment. After storage at room temperature (20 to 22 °C), the image density (o.D.) was measured through each tape after 24 hours and after 7 days, and correlated with the similar measured image density values of freshly adhered samples according to equation (Equation 1).

[0261]

[0262] The spread (Streuung) of the % values calculated according to (Equation 1) is ≤ ±2 percentage points.

[0263] Tables 3 to 5 summarize the evaluation of the prepared recording materials.

[0264] Table 3: Starting temperature (starting point) of the color former and image density (optical density at energy levels of 0.25 and 0.45 mJ / spot)

[0265] Developer o.D. (0.25 mJ / dot) o.D. (0.45 mJ / dot) Starting Point (°C) I 1.16 1.22 81 II 1.20 1.24 76 III 1.13 1.24 76 IV 1.19 1.20 71 V 1.17 1.20 76 VII 1.15 1.23 86 VIII 1.20 1.23 73 X 1.24 1.30 82 XIII 1.14 1.20 79 XXIII 1.16 1.26 82 XXIV 1.09 1.26 82 Z 1.19 1.24 86 PF201 1.19 1.23 76

[0266] Table 4: Image density (optical density at energy levels of 0.25 and 0.45 mJ / spot) depending on the substitution pattern of the color former

[0267]

[0268] *: Comparative example

[0269] Table 5: Resistance of the printed image of the color former

[0270]

[0271] * Percentage of the retained image density corresponding to Equation 1

[0272] It can be seen from the foregoing examples that the thermosensitive recording material of the present invention particularly exhibits the following advantageous properties:

[0273] (1) The recorded images of the thermosensitive recording material based on the color former according to the present invention have a printing density (optical density) comparable to those of the comparative samples of the prior art (Table 3).

[0274] (2) The thermosensitive recording material based on a color former having the substitution pattern according to the present invention (1,2-position (ortho) of the relevant functional group) has a significantly higher printing density than the recording material based on a color former having an alternative substitution pattern (1,3-position and 1,4-position of the relevant functional group). See II and XIV and XVII, III and XV and XVIII, and IV and XVI and XIX (Table 4).

[0275] (3) The temperature at which the recording material according to the present invention begins to visibly turn gray (static starting point) meets the requirements of a marketable thermosensitive recording material (Table 3).

[0276] (4) After the action of a hydrophobic reagent (binder, plasticizer), the image resistance is better or comparable to the corresponding properties of known non-phenolic color former substances of the prior art (Table 5).

[0277] (5) By using the color former according to the present invention, a thermosensitive recording material with high value in terms of key application technology relationships can be obtained. Recording materials based on known color formers do not have comparable performance characteristics that are balanced in all tested properties.

Claims

1. A thermosensitive recording material comprising a carrier substrate and a thermosensitive coloring layer containing at least one color former and at least one phenol-free developer, wherein at least one developer is a compound of formula (I). (Ar 1 -SO2-NH-) m -Y-(-NH-C(O)-NH-SO2-Ar 2 ) n (I) Among them, Ar 1 is an unsubstituted or monosubstituted phenyl group, where the monosubstituted phenyl group is substituted by a C1-C5 alkyl group, RO-, halogen or NO2- group, where R is a C1-C5 alkyl group, Ar 2 is an unsubstituted or monosubstituted phenyl group, where the monosubstituted phenyl group is substituted by a C1-C4 alkyl group, Y is a benzene group substituted (m + n) times, where m = 1 and n = 1 or 2, and Y is substituted such that at least one Ar 2 -SO2-NH-C(O)-NH- group is in the ortho position to at least one Ar 1 -SO2-NH group.

2. The thermosensitive recording material according to claim 1, wherein the at least one color former is a dye of triphenylmethane type, fluoran type, azaphthalide type, and / or fluorene type.

3. The thermosensitive recording material according to claim 1, wherein in addition to the compound of formula (I), there is one or more other non-phenolic developers.

4. The thermosensitive recording material according to claim 1, wherein the compound of formula (I) is present in an amount of 3 to 35% by weight, based on the total solids content of the thermosensitive layer.

5. The thermosensitive recording material according to claim 1, wherein the compound of formula (I) is present in an amount of 10 to 25% by weight, based on the total solids content of the thermosensitive layer.

6. The thermosensitive recording material according to claim 1, wherein the thermosensitive coloring layer contains a urea-carbamate compound of general formula (II). 。 7. A method for preparing the thermosensitive recording material according to any one of claims 1 to 6, wherein an aqueous suspension of a starting material containing a thermosensitive coloring layer is applied to a carrier substrate and dried, wherein the aqueous coating suspension has a solids content of 20 to 75% by weight, and is applied using a curtain coating method at a coating device running speed of at least 400 m / min, and dried.

8. The method according to claim 7, wherein the aqueous coating suspension has a solids content of 30 to 50% by weight.

9. The method according to claim 7, wherein the aqueous coating suspension is applied using a curtain coating method at a coating device running speed of at least 1000 m / min.

10. The method according to claim 7, wherein the aqueous coating suspension is applied using a curtain coating method at a coating device running speed of at least 1500 m / min.

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