Heat-sensitive recording material
10850546 ยท 2020-12-01
Assignee
Inventors
Cpc classification
B41M5/323
PERFORMING OPERATIONS; TRANSPORTING
B41M2205/04
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
A heat-sensitive recording material having i) a carrier substrate and ii) a heat-sensitive recording layer. The heat-sensitive recording layer contains a color former and a color developer mixture and the color developer mixture contains a) N/-[2-(3-phenylureido)phenyl]benzole sulfonamide (compound of formula (I)). The compound of formula (I) is present in a crystalline form, which has an absorption band in the IR spectrum at 340120 cm1, and b) N-(4-methylphenylsulfonyl)-N-(3-(4-methylphenylsulfonyloxy)phenyl)urea (compound of formula (II)).
Claims
1. A heat-sensitive recording material, comprising: i) a supporting substrate; and ii) a heat-sensitive recording layer, comprising: a colour former; and a colour developer mixture that comprises: a) a compound of a formula (I) ##STR00005## wherein the compound of the formula (I) is in a crystalline form having an absorption band at 340120 cm.sup.1 in an IR spectrum, and b) a compound of a formula (II) ##STR00006##
2. The heat-sensitive recording material according to claim 1, wherein a mass ratio between the compound of the formula (I) and the compound of the formula (II) is at least one of: 0.5:99.5 to 99.5:0.5; 35:65 to 65:35; 40:60 to 60:40 and 45:55 to 55:45.
3. The heat-sensitive recording material according to claim 1, wherein the supporting substrate is one of: a paper, a synthetic paper, and a polymeric film.
4. The heat-sensitive recording material according to claim 1, wherein a fraction of the colour developer mixture in the heat-sensitive recording layer is at least one of: 35 to 15 wt %; 31 to 19 wt %; and 28 to 22 wt %, based on a total solids fraction of the heat-sensitive recording layer.
5. The heat-sensitive recording material according to claim 1, wherein a mass of the heat-sensitive recording layer per unit area is in a range from one of: 1.5 to 6 g/m.sup.2 and 2.0 to 5.5 g/m.sup.2.
6. The heat-sensitive recording material according to claim 1, further comprising: an interlayer located between the supporting substrate and the heat-sensitive recording layer.
7. The heat-sensitive recording material according to claim 6, wherein the interlayer comprises pigments, and wherein the pigments are at least one of: a) organic pigments, b) organic hollow-body pigments, and c) inorganic pigments.
8. The heat-sensitive recording material according to claim 1, wherein the heat-sensitive recording layer is at least partly covered by a protective layer.
9. The heat-sensitive recording material according to claim 1, wherein the colour former is selected from derivatives of compounds from the group consisting of fluoran, phthalide, lactam, triphenylmethane, phenothiazine, and spiropyran.
10. The heat-sensitive recording material according to claim 1, wherein the heat-sensitive recording layer further comprises a binder.
11. The heat-sensitive recording material according to claim 1, wherein the heat-sensitive recording layer further comprises a sensitizer.
12. The heat-sensitive recording material according to claim 1, wherein the heat-sensitive recording material is configured as at least one of an entrance ticket, a flight ticket, a rail ticket, a ship ticket, a bus ticket, a gambling ticket, a pay and display ticket, a label, a till receipt, a bank statement, a sticker, medical diagram paper, fax paper, security paper, and a barcode label.
13. The heat-sensitive recording material according to claim 1, wherein the compound of the formula (I) improves the water resistance of a printed image on the heat-sensitive recording material, and wherein a mass ratio between the compound of the formula (I) and the compound of the formula (II) is at least one of: 0.5:99.5 to 35:65, 5:95 to 30:70, and 15:85 to 25:75.
14. The heat-sensitive recording material according to claim 6, wherein the interlayer comprises pigments.
15. The heat-sensitive recording material according to claim 7, wherein the inorganic pigments are selected from the list consisting of calcined kaolin, silicon oxide, bentonite, calcium carbonate, aluminium oxide, and boehmite.
16. The heat-sensitive recording material according to claim 10, wherein the binder is a crosslinked or uncrosslinked binder selected from the group consisting of polyvinyl alcohol, carboxyl-modified polyvinyl alcohol, ethylene-vinyl alcohol copolymer, a combination of polyvinyl alcohol and ethylene-vinyl alcohol copolymer, polyvinyl alcohol modified with silanol groups, diacetone-modified polyvinyl alcohol, acrylate copolymer, and film-forming acrylic copolymers.
17. The heat-sensitive recording material according to claim 11, wherein the sensitizer has a melting point of at least one of: 60 C. to 180 C. and 80 C. to 140 C.
18. The heat-sensitive recording material according to claim 17, wherein the sensitizer is selected from the group consisting of benzyl p-benzyloxy-benzoate, stearamide, N-methylolstearamide, p-benzylbiphenyl, 1,2-di(phenoxy)ethane, 1,2-di(m-methylphenoxy)ethane, m-terphenyl, dibenzyl oxalate, benzyl naphthyl ether and diphenyl sulfone, more preferably benzyl naphthyl ether, diphenyl sulfone, 1,2-di(m-methylphenoxy)ethane, and 1,2-di(phenoxy)ethane.
19. A method for producing a heat-sensitive recording material, comprising: i) providing or producing a supporting substrate; ii) providing or producing a coating composition comprising a compound of a formula (I) ##STR00007## wherein the compound of the formula (I) is in a crystalline form having an absorption band at 340120 cm.sup.1 in an IR spectrum, and b) a compound of the formula (II) ##STR00008## iii) applying the coating composition provided or produced to the supporting substrate; and iv) drying the applied coating composition to form a heat-sensitive recording layer.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
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(23) The examples and comparative examples below will further explain the invention:
Examples 1 to 3 and Comparative Examples 1 and 2
(24) A paper web of bleached and ground deciduous and coniferous pulps with a mass per unit area of 67 g/m.sup.2 with addition of conventional additives in conventional quantities is produced as supporting substrate on a fourdrinier paper machine. On the front side an interlayer comprising hollow-space pigments and calcined kaolin as pigment, styrene-butadiene latex as binder and starch as co-binder with a mass per unit area of 9 g/m.sup.2 is applied using a roller doctor-knife coating mechanism and dried conventionally.
(25) A heat-sensitive recording layer with a mass per unit area of 6.0 g/m.sup.2 is applied to the interlayer by means of roller doctor-knife coating mechanism using a coating machine and dried conventionally after the application.
(26) A formulation, which comprises as binder a mixture comprising polyvinyl alcohol and an acrylate copolymer and as pigment calcium carbonate, is used for the heat-sensitive recording layer. Further constituents of the heat-sensitive recording layers of the individual exemplary embodiments are indicated in Table 1 below:
(27) TABLE-US-00001 TABLE 1 3-N-di-n- butylamine-6- methyl-7- Compound of the Compound of the anilinofluoran formula (I) formula (II) (colour former) Example 1 50 absolutely dry 50 absolutely dry 50 absolutely dry (according to parts by weight parts by weight parts by weight the invention) Example 2 90 absolutely dry 10 absolutely dry 50 absolutely dry (according to parts by weight parts by weight parts by weight the invention) Example 3 10 absolutely dry 90 absolutely dry 50 absolutely dry (according to parts by weight parts by weight parts by weight the invention) Comparative 100 absolutely 0 absolutely dry 50 absolutely dry example 1 (not dry parts by parts by weight parts by weight according to weight the invention) Comparative 0 absolutely dry 100 absolutely 50 absolutely dry example 2 (not parts by weight dry parts by parts by weight according to weight the invention)
(28) In paper production, three grades of dry content of paper and pulp are differentiated absolutely dry, air dry and oven dry. The detail is effected in each case in % absolutely dry, % air dry and % oven dry. Where absolutely dry represents a paper or pulp with 0% water content. A normal moisture content (basically necessary for the paper) is thus used as the basis of the calculation for air dry. For pulp and wood pulp, the calculation mass usually relates to 90:100, that is, 90 parts of the material, 10 parts of water. The state of paper or pulp after drying under fixed, defined conditions is designated as oven dry.
Examples 4 to 6
(29) Examples 4 to 6 were carried out analogously to Examples 1 to 3. However, the interlayer is not applied using a roller doctor-knife coating mechanism, but an outline coating is pulled as an interlayer using a blade.
(30) The heat-sensitive recording layer is applied by a curtain coating mechanism, where the mass per unit area is 1.5 up to 6.0 g/m.sup.2, preferably 2 to 5.5 g/m.sup.2. The 3-N-di-n-butylamine-6-methyl-7-anilinofluoran (colour former) is added in a quantity of 40-60 absolutely dry parts by weight.
(31) Determination of the Long-Term Climatic Resistance of Heat-Sensitive Recording Materials (at 40 C. and 90% Relative Humidity):
(32) To record the climatic resistance of a thermal print-out in terms of measuring technology on the heat-sensitive recording materials of Examples 1, 2 and 3 of the invention and of Comparative examples 1 and 2, in each case black/white-chequered thermal sample print-outs were generated on the heat-sensitive recording materials to be tested using a device of the type Atlantek 400 from Printrex (USA), where a thermal head with a resolution of 300 dpi and an energy per surface unit of 16 mJ/mm.sup.2 was used.
(33) After generating the black/white-chequered thermal sample print-out, after a rest time of more than 5 minutes, a determination of the print density by a densitometer TECHKON SpectroDens Advancedspectral densitometer was carried out on in each case three points of the black-coloured surfaces of the thermal sample print-out. In each case the average value was formed from the respective measured values of the black-coloured surfaces.
(34) A thermal sample print-out was suspended in a climatic test cabinet at 40 C. and a relative humidity of 90%. After 1, 2, 3, 6, 10, 20 and 38 days, the thermal paper print-out was removed, cooled to room temperature and a determination of the print density by a densitometer TECHKON SpectroDens Advancedspectral densitometer was carried out again on in each case three points of the black-coloured surfaces of the thermal sample print-out. In each case the average value was formed from the respective measured values of black-coloured surfaces. After each measurement, the thermal sample print-out was suspended in the climatic test cabinet until the next measurement again at 40 C. and a relative humidity of 90%.
(35) The measured results thus obtained are listed in Table 2 and shown in
(36) TABLE-US-00002 TABLE 2 Print density 1 d 2 d 3 d 6 d 10 d 20 d 38 d Example 1 0.92 0.88 0.87 0.86 0.84 0.82 0.74 [Formula (II) 90%/ Formula (I) 10%] Example 2 1.04 1.02 1.01 1.01 1.00 0.99 0.93 [Formula (II) 50%/ Formula (I) 50%] Example 3 1.12 1.10 1.09 1.08 1.06 0.99 0.89 [Formula (II) 10%/ Formula (I) 90%] Comparative 0.88 0.84 0.83 0.81 0.79 0.76 0.68 example 1 [Formula (II)] Comparative 1.10 1.07 1.06 1.01 0.96 0.84 0.64 example 2 [Formula (I)]
(37) The measured results reproduced in Table 2 show that the print density of Examples 1, 2 and 3 decreases less than the print density from Comparative examples 1 and 2. The resistance of the printed image at 40 C. and 90% relative humidity is therefore higher for the examples of the invention than for Comparative examples 1 and 2. The combination used according to the invention of a compound of the formula (I) with a compound of the formula (II) thus has a synergistic effect, since the mixture of the compounds of the formula (I) and (II) has better properties than the respective compounds alone.
(38) Examples 4 to 6 of the invention were likewise measured and likewise showed that the print density decreases less than the print density from Comparative examples 1 and 2.
(39) Determination of the Climatic Resistance of Heat-Sensitive Recording Materials (at 60 C.):
(40) The determination was carried out analogously to determine the climatic resistance of heat-sensitive recording materials (at 40 C. and 90% relative humidity), however storage was not effected in a climatic test cabinet, but in a drying cabinet at 60 C.
(41) The measured results thus obtained are listed in Table 3 and shown in
(42) TABLE-US-00003 TABLE 3 Print density 1 d 2 d 3 d 6 d 10 d 20 d 38 d Example 1 1.10 1.09 1.07 1.04 1.02 0.97 0.92 [Formula (II) 90%/ Formula (I) 10%] Example 2 1.13 1.11 1.10 1.07 1.05 1.01 0.97 [Formula (II) 50%/ Formula (I) 50%] Example 3 1.14 1.12 1.10 1.07 1.03 0.98 0.94 [Formula (II) 10%/ Formula (I) 90%] Comparative 1.09 1.07 1.06 1.03 0.99 0.95 0.90 example 1 [Formula (II)] Comparative 1.06 1.02 0.98 0.91 0.87 0.80 0.78 example 2 [Formula (I)]
(43) The measured results reproduced in Table 3 show that the print density of Examples 1, 2 and 3 decreases less than the print density from Comparative examples 1 and 2. The resistance of the printed image at 60 C. is therefore higher for the examples of the invention than for Comparative examples 1 and 2. The combination used according to the invention of a compound of the formula (I) with a compound of the formula (II) thus has a synergistic effect, since the mixture of the compounds of the formula (I) and (II) has better properties than the respective compounds alone.
(44) Examples 4 to 6 of the invention were likewise measured and likewise showed that the print density decreases less than the print density from Comparative examples 1 and 2.
(45) Determination of the Resistance of Heat-Sensitive Recording Materials with Respect to Lanolin:
(46) To record the resistance of a thermal print-out in terms of measuring technology on the heat-sensitive recording materials of Examples 1, 2 and 3 of the invention and of Comparative examples 1 and 2 with respect to lanolin, in each case black/white-chequered thermal sample print-outs were generated on the heat-sensitive recording materials to be tested using a device of the type Atlantek 400 from Printrex (USA), where a thermal head with a resolution of 300 dpi and an energy per surface unit of 16 mJ/mm.sup.2 was used.
(47) After generating the black/white-chequered thermal sample print-outs, after a rest time of more than 5 minutes, a determination of the print density by means of a densitometer TECHKON SpectroDens Advancedspectral densitometer was carried out on three points of the black-coloured surfaces of the thermal sample print-outs. The average value was formed from the respective measured values.
(48) Subsequently, the generated thermal sample print-out of the heat-sensitive recording material to be tested was coated fully with lanolin. After an action time of 10 minutes, the lanolin is carefully wiped away and subsequently stored at 23 C. and 50% air humidity. After 1, 2, 4, 24 and 96 hours, the thermal paper print-out was removed and a determination of the print density by means of a densitometer TECHKON SpectroDens Advancedspectral densitometer was again on in each case three points of the black-coloured surfaces of the thermal sample print-outs. After each measurement, the thermal sample print-out was suspended in the climatic test cabinet until the next measurement again at 23 C. and a relative humidity of 50%.
(49) The average value was formed from the respective measured values.
(50) The measured results thus obtained are listed in Table 4 and shown in
(51) TABLE-US-00004 TABLE 4 Print density 1 h 2 h 4 h 24 h 96 h Example 1 0.82 0.82 0.79 0.74 0.72 [Formula (II) 90%/ Formula (I) 10%] Example 2 0.85 0.83 0.83 0.78 0.75 [Formula (II) 50%/ Formula (I) 50%] Example 3 0.78 0.76 0.74 0.38 0.18 [Formula (II) 10%/ Formula (I) 90%] Comparative 0.79 0.79 0.77 0.72 0.68 example 1 [Formula (II)] Comparative 0.72 0.62 0.54 0.19 0.13 example 2 [Formula (I)]
(52) The measured results reproduced in Table 4 show that the print density of Examples 1 and 3 decreases less than the print density from Comparative examples 1 and 2. The resistance of the printed image of Examples 1 and 3 with respect to lanolin is therefore higher for the examples of the invention than for Comparative examples 1 and 2. In Example 2, the print density decreases less than in Comparative example 1. The combination used according to the invention of a compound of the formula (I) with a compound of the formula (II) thus has a synergistic effect, since the mixture of the compounds of the formula (I) and (II) has better properties than the respective compounds alone.
(53) Examples 4 to 6 of the invention were likewise measured and likewise showed that the print density decreases less than the print density from Comparative examples 1 and 2.
(54) Resistance to Water and Aqueous Ethanol Solutions (23 C., 50% Relative Humidity, 24 Hours):
(55) The resistance of the image generated on the recording layer to water and aqueous solutions is assessed with the aid of these tests. One drop of distilled water or the selected aqueous 25% strength ethanol solution is applied to the printed surfaces generated using the printer ATLANTEK Model 400Thermal Response Test System with the energy level Medium Stage 10. The excess test liquid is blotted after 20 minutes action time using a filter paper or cotton cloth and the test sheet is then stored for 24 hours at room climate (23 C., 50% relative moisture). Before applying the respective test liquid and after lapsing of the storage time, the optical density of the printed surfaces and the difference thereof is determined using the TECHKON SpectroDens Advanced-spectral densitometer.
(56) The resistance with respect to water or aqueous ethanol solutions corresponds to the quotients from the average value of the print density formed before and after the treatment with the respective test liquid multiplied by 100.
(57) The measured results thus obtained are listed in Table 5 below:
(58) TABLE-US-00005 TABLES 5 Results of the resistance test to water and aqueous ethanol solutions (Part 1) (Comparison represents Comparative example) Example No.: 1 2 3 Comparison 1 Comparison 2 Water resistance (23 C., 50% relative humidity 24 hours): Resistance 80.2 81.7 84.7 80.2 80.2 Resistance to 25% strength aqueous ethanol solution (23 C., 50% relative humidity, 24 hours): Resistance 86.3 87.0 89.9 89.7 87.0
(59) The reproduced measured results show that the resistance of the printed image with respect to water and aqueous ethanol solution in Examples 1 to 3 of the invention has not diminished compared to Comparative examples 1 and 2.
(60) Examples 4 to 6 of the invention were likewise measured and likewise showed no diminishing of the resistance with respect to water and aqueous ethanol solution.
(61) Production of the Crystalline Form Used According to the Invention of the Compound with the Formula (I):
(62) The commercially available compound of the formula (I) or that described in WO 2014/080615 A1 having a melting point of about 158 C. is recrystallized from ethanol. The compound of the formula (I) used according to the invention having a melting point of about 175 C. is obtained. The compound of the formula (I) used according to the invention has an absorption band at 340120 cm1 in the IR spectrum.
(63) The compound of the formula (I) obtained by recrystallization from ethanol is characterized with the assistance of .sup.1H-NMR spectroscopy in DMSO-D6 as solvent. The .sup.1H-NMR spectrum of the compound of the formula (I) produced by recrystallization does not differ from the .sup.1H-NMR spectrum of the starting compound. This is also not to be expected, since after resolving the crystalline forms in DMSO-D6, solids are no longer present. However, it may be ruled out by the investigation that during recrystallization an unexpected chemical reactionfor example with ethanolhas taken place or that solvates were formed. Solvates with ethanol would be able to be detected by the presence of additional signals in the .sup.1H-NMR (triplet at about 1.06 ppm (CH.sub.3), quartet at about 3.44 ppm (CH.sub.2) and an OH signal at about 3.39 ppm), which is not the case here.
(64) In the thermogravimetric analysis (TGA) of the compound of the formula (I) obtained by recrystallization from ethanol, no mass change is shown when heating the sample in the temperature range between 25 and 150 C. For impurities with volatile compounds, such as for example ethanol, a mass change of the sample would be observable at the boiling point of the volatile compound, since the volatile compound boils and thus escapes from the sample and thus leads to a drop in mass. This is not the case here. The results of the thermogravimetric analysis are shown in
(65) Even for measurements with assistance of dynamic differential calorimetry (DSC), in the compound of the formula (I) obtained by recrystallization from ethanol no exothermic or endothermic processes or phase changes may be observed up to a temperature of over 170 C. The first phase change during heating corresponds to the melting point of the compound produced at 175 C. In the presence of solvates, in dynamic differential calorimetry corresponding phase changes would be observed, for example if the boiling point of the solvating compound is achieved. Presence of solvates may therefore be ruled out in the present case. The results of dynamic differential calorimetry are shown in
(66) Both a sample of the starting compound and a sample of the crystalline form of the compound of the formula (I) produced by recrystallization from ethanol was investigated with the aid of liquid chromatography with mass spectrometry coupling (LC-MS). In the investigation, no impurities could be detected in either sample and both compounds had the identical molar mass, with identical isotope distribution. The results of liquid chromatography with mass spectrometry coupling are shown in
(67) The investigations show that it is possible to convert the commercially available compound of the formula (I) or that described in WO 2014/080615 A1 having a melting point of about 158 C. into the compound of the formula (I) used according to the invention having a melting point of about 175 C. by recrystallization from ethanol. In the compound of the formula (I), polymorphy may be detected by these tests, that is, it is a substance which may occur in different modes (modifications). They have the same chemical composition (stoichiometry), but differ in the spatial arrangement of the molecules and have different physical properties. These investigations may rule out the fact that an undesirable chemical reaction of the compound has taken place or that solvates were present after recrystallization.
(68) In addition to recrystallization from ethanol, it is also possible to use other solvents to reach a compound of the formula (I) used according to the invention.
(69) Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.