Heat-sensitive recording material

Abstract

The invention relates to a heat-sensitive recording material, comprising a carrier substrate and a heat-sensitive colour-forming layer, which contains at least one colour former and at least one phenol-free colour developer, characterised in that the at least one colour developer is the compound of formula (A), Ar(NH—CO—NH—CO—NH—Ar.sup.1).sub.n (A), wherein Ar is an unsubstituted or substituted phenyl or naphthyl group, Ar.sup.1 is an unsubstituted or substituted phenyl, naphthyl, pyridyl, thiazolyl or benzothiazolyl group, and n is 1 or 2.

Claims

1. Heat-sensitive recording material comprising a carrier substrate and a heat-sensitive colour-forming layer, which contains at least one colour former and at least one phenol-free colour developer, characterised in that the at least one colour developer is the compound of formula (A)
Ar(NH—CO—NH—CO—NH—Ar.sup.1).sub.n  (A), wherein Ar is an unsubstituted or substituted phenyl or naphthyl group, Ar.sup.1 is an unsubstituted or substituted phenyl, naphthyl, pyridyl, thiazolyl or benzothiazolyl group, and n is 1 or 2.

2. Heat-sensitive recording material according to claim 1, characterised in that n is 1.

3. Heat-sensitive recording material according to claim 1, characterised in that Ar is a phenyl group substituted with a C.sub.1-C.sub.4 alkyl group, an alkenyl group, an alkynyl group, a benzyl group, a halogen group, an NO.sub.2 group, a CN group, a formyl group, an ROC group, an RO group, an RO.sub.2C group, an ROCO group, an R—SO.sub.2O group, an RO—SO.sub.2 group, an RNHCO group, an RCONH group, an R—NH—SO.sub.2 group, or an R—SO.sub.2—NH group, wherein R is a C.sub.1-C.sub.4 alkyl group, an alkenyl group, an alkynyl group, a phenyl group, a tolyl group, or a benzyl group.

4. Heat-sensitive recording material according to claim 1, characterised in that Ar is an unsubstituted phenyl group, a 4-acetyl-phenyl group, a 3-chloro-phenyl group, or a 4-methoxy-phenyl group.

5. Heat-sensitive recording material according to claim 1, characterised in that Ar.sup.1 is a phenyl group substituted with a C.sub.1-C.sub.4 alkyl group, an alkenyl group, an alkynyl group, a benzyl group, a halogen group, an NO.sub.2 group, a CN group, a formyl group, an R.sup.1OC group, an R.sup.1O group, an R.sup.1O.sub.2C group, an R.sup.1OCO group, an R.sup.1—SO.sub.2O group, an R.sup.1O—SO.sub.2 group, an R.sup.1NHCO group, an R.sup.1CONH group, an R.sup.1—NH—SO.sub.2 group, or an R.sup.1—SO.sub.2—NH group, wherein R.sup.1 is a C.sub.1-C.sub.4 alkyl group, an alkenyl group, an alkynyl group, a phenyl group, a tolyl group, a benzyl group, a thiazolyl group, a benzothiazolyl group, or a pyrimidyl group.

6. Heat-sensitive recording material according to claim 1, characterised in that Ar.sup.1 is a phenyl group substituted in the 3- or 4-position with an R.sup.1O—SO.sub.2 group or an R.sup.1—SO.sub.2O group.

7. Heat-sensitive recording material according to claim 1, characterised in that the carrier substrate is paper, synthetic paper and/or a plastics film.

8. Heat-sensitive recording material according to claim 1, characterised in that the at least one colour former is a dye of the triphenylmethane type, of the fluoran type, of the azaphthalide type and/or of the fluorene type.

9. Heat-sensitive recording material according to claim 1, characterised in that the compound of formula (A) is present in an amount of from about 3 to about 35% by weight in relation to the total solids content of the heat-sensitive layer.

10. Heat-sensitive recording material according to claim 1, characterised in that the heat-sensitive colour-forming layer comprises at least one sensitising agent.

11. Heat-sensitive recording material according to claim 1, characterised in that the heat-sensitive colour-forming layer contains additives selected from stabilisers, binders, release agents, pigments and/or brighteners.

12. Heat-sensitive recording material according to claim 1, characterised in that the applied weight per unit area of the (dry) heat-sensitive layer is about 1 to about 10 g/m.sup.2.

13. Heat-sensitive recording material according to claim 1, characterised in that the dried heat-sensitive colour-forming layer is subjected to a smoothing measure in such a way that it has a Bekk smoothness, measured according to ISO 5627: 1995, of from about 100 to about 1000 sec.

14. Heat-sensitive recording material according to claim 1, characterised in that at least one further intermediate layer is present between the carrier substrate and the heat-sensitive colour-forming layer.

15. Method for producing a heat-sensitive recording material according to claim 1, wherein an aqueous suspension containing the starting materials of the heat-sensitive colour-forming layer is applied to a carrier substrate and dried, the aqueous application suspension having a solids content of from about 20 to about 75% by weight, and being applied and dried by the curtain coating process at an operating speed of the coating plant of at least about 400 m/min.

16. Heat-sensitive recording material obtainable by the process according to claim 15.

17. A method of thermal printing comprising thermally printing upon a paper including the heat-sensitive recording material of claim 1.

18. Heat-sensitive recording material according to claim 1, characterised in that that at least one colour former is a dye of the fluoran type and the applied weight per unit area of the (dry) heat-sensitive layer is about 3 to about 6 g/m.sup.2 and the compound of formula (A) is present in an amount from about 10 to about 25% by weight.

19. Heat-sensitive recording material according to claim 14, characterised in that the at least one further intermediate layer contains organic hollow sphere pigments and/or calcined kaolins.

20. Method for producing a heat-sensitive recording material according to claim 1, wherein an aqueous suspension containing the starting materials of the heat-sensitive colour-forming layer is applied to a carrier substrate and dried, the aqueous application suspension having a solids content of from about 30 to about 50% by weight, and being applied and dried by a curtain coating process at an operating speed of a coating plant of at least about 1500 m/min.

Description

EXAMPLES

(1) The compounds I-XXIX (Table 2) were produced as described below:

(2) TABLE-US-00002 TABLE 2 Composition of selected compounds of formula (A) Ar Ar.sup.1 n I C.sub.6H.sub.5 C.sub.6H.sub.5 1 II C.sub.6H.sub.5 4-CH.sub.3—C.sub.6H.sub.4 1 III C.sub.6H.sub.5 2-Cl—C.sub.6H.sub.4 1 IV C.sub.6H.sub.5 3-Cl—C.sub.6H.sub.4 1 V C.sub.6H.sub.5 4-Cl—C.sub.6H.sub.4 1 VI C.sub.6H.sub.5 4-CH.sub.3O—C.sub.6H.sub.4 1 VII C.sub.6H.sub.5 4-CH.sub.3CO—C.sub.6H.sub.4 1 VIII C.sub.6H.sub.5 4-NO.sub.2—C.sub.6H.sub.4 1 IX C.sub.6H.sub.5 4-(CO.sub.2CH.sub.3)—C.sub.6H.sub.4 1 X C.sub.6H.sub.5 2-(CO.sub.2C.sub.2H.sub.5)—C.sub.6H.sub.4 1 XI C.sub.6H.sub.5 4-(CO.sub.2C.sub.6H.sub.5)—C.sub.6H.sub.4 1 XII C.sub.6H.sub.5 3-(OCOC.sub.6H.sub.5)—C.sub.6H.sub.4 1 XIII C.sub.6H.sub.5 3-[OSO.sub.2—(4-CH.sub.3—C.sub.6H.sub.4)]—C.sub.6H.sub.4 1 XIV C.sub.6H.sub.5 4-[OSO.sub.2—(4-CH.sub.3—C.sub.6H.sub.4)]—C.sub.6H.sub.4 1 XV C.sub.6H.sub.5 3-[SO.sub.2O—(4-CH.sub.3—C.sub.6H.sub.4)]—C.sub.6H.sub.4 1 XVI C.sub.6H.sub.5 4-[SO.sub.2O—(4-CH.sub.3—C.sub.6H.sub.4)]—C.sub.6H.sub.4 1 XVII C.sub.6H.sub.5 4-[SO.sub.2NH—(2-thiazolyl)]—C.sub.6H.sub.4 1 XVIII C.sub.6H.sub.5 4-[SO.sub.2NH-2-(4-CH.sub.3-pyrimidyl)]—C.sub.6H.sub.4 1 XIX C.sub.6H.sub.5 1-naphthyl 1 XX C.sub.6H.sub.5 2-thiazolyl 1 XXI C.sub.6H.sub.5 2-benzothiazolyl 1 XXII C.sub.6H.sub.5 2-pyridyl 1 XXIII C.sub.6H.sub.5 4-pyridyl 1 XXIV 4-CH.sub.3CO—C.sub.6H.sub.4 4-CH.sub.3CO—C.sub.6H.sub.4 1 XXV 4-CH.sub.3CO—C.sub.6H.sub.4 3-[OSO.sub.2—(4-CH.sub.3—C.sub.6H.sub.4)]—C.sub.6H.sub.4 1 XXVI 4-CH.sub.3CO—C.sub.6H.sub.4 4-[SO.sub.2O—(4-CH.sub.3—C.sub.6H.sub.4)]—C.sub.6H.sub.4 1 XXVII 4-CH.sub.3CO—C.sub.6H.sub.4 4-[SO.sub.2O—(4-CH.sub.3—C.sub.6H.sub.4)]—C.sub.6H.sub.4 1 XXVIII 3-Cl—C.sub.6H.sub.4 4-[SO.sub.2O—(4-CH.sub.3—C.sub.6H4)]—C.sub.6H.sub.4 1 XXIX 1,4-C.sub.6H.sub.4 C.sub.6H.sub.5 2

(3) Stage A—production of urea (based on R. C. Moschel, W. R. Hudgins, A. Dipple, J. Org. Chem., 51 (22), 4180 (1986)):

(4) A solution of 15 mmol potassium cyanate in 10 mL water is added to a solution of 10 mmol amine and 10 mmol hydrochloric acid (25%) in 30 mL water. The solution is stirred for 18 h at room temperature. The precipitated urea is filtered off, washed with 30 mL water, and recrystallised from dichloromethane or ethyl acetate.

(5) Stage B—production of the allophanates (based on M. M. Al Sabbagh, M. Calmon, J. P. Calmon, Bull. Soc. Chim. Fr., 3-4 (Pt. 2), 73 (1983)):

(6) A solution of 66 mmol phenylchloroformate in 20 mL dichloromethane is added dropwise at room temperature with stirring to a solution of 66 mmol of the corresponding urea and 73 mmol of pyridine in 80 mL dichloromethane. The reaction solution is stirred for 18 hours at room temperature and then mixed with 100 mL water. The phases are separated. The organic phase is washed with 100 mL water. This process is repeated before, after extracting the combined aqueous phases twice with 100 mL dichloromethane, the combined organic phases are dried over magnesium sulfate. After removing the solvent in a vacuum, the purification is carried out by recrystallisation from dichloromethane and a few drops of n-hexane.

(7) Stage C—production of the biuret (based on F. H. S. Curd, D. G. Davey, D. N. Richardson, J. Chem. Soc., 1732 (1949)):

(8) A solution of 10 mmol of the corresponding amine in 60 mL dichloromethane is added dropwise at room temperature with stirring to a solution of 10 mmol of the corresponding allophanate and 10 mmol potassium carbonate in 240 mL dichloromethane. The reaction mixture is refluxed for 18 hours and then mixed with 300 mL water. The aqueous phase is separated. The organic phase is again mixed with 300 mL water and the aqueous phase is neutralised by adding 25% hydrochloric acid. The phases are separated. After extraction of the aqueous phase with 300 mL dichloromethane, the combined organic phases are washed with 300 mL water and dried over magnesium sulfate. After removing the solvent in a vacuum, the purification is carried out by recrystallisation from dichloromethane and a few drops of n-hexane.

(9) The starting compounds are either commercially available or were produced according to provisions known from the literature.

(10) Analytical Data:

(11) I, C.sub.14H.sub.13N.sub.3O.sub.2, M=255.3, 1-phenyl-3-(phenyl carbamoyl)urea

(12) MS (ESI): m/z (%)=256.1 (90) [M+H].sup.+, 137.1 (100) [M+H-Ar.sup.1NCO].sup.+. .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=9.71 (2H, s), 9.07 (1H, s), 7.51-7.49 (4H, m), 7.35-7.32 (4H, m), 7.09-7.06 (2H, m).

(13) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=151.95 (NHCONH), 137.82, 128.87, 123.29, 119.27.

(14) II, C.sub.15H.sub.15N.sub.3O.sub.2, M=269.3, 1-(4-methylphenyl)-3-(phenylcarbamoyl)urea

(15) MS (ESI): m/z (%)=270.1 (100) [M+H].sup.+.

(16) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=9.76 (1H, s), 9.64 (1H, s), 9.06 (1H, s), 1.50-7.48 (2H, m), 7.38-7.36 (2H, m), 7.34-7.31 (2H, m), 7.14-7.12 (2H, m), 7.08-7.05 (1H, m), 2.26 (3H, s).

(17) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=151.99 (NHCONH), 151.97 (NHCONH), 137.90, 135.28, 132.32, 129.30, 128.91, 123.28, 119.32, 119.24, 20.33 (CH.sub.3).

(18) III, C.sub.14H.sub.12ClN.sub.3O.sub.2, M=289.7, 1-(2-chlorophenyl)-3-(phenylcarbamoyl)urea

(19) MS (ESI): m/z (%)=290.1 (98) [M+H].sup.+.

(20) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.44 (1H, s), 9.42 (1H, s), 9.40 (1H, s), 8.22 (1H, dd, J=8.3, 1.5 Hz), 7.50 (1H, dd, J=8.0, 1.5 Hz), 7.48-7.46 (2H, m), 7.36-7.32 (3H, m), 7.12-7.07 (2H, m).

(21) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=152.50 (NHCONH), 151.37 (NHCONH), 137.71, 134.81, 129.22, 128.93, 127.68, 124.35, 123.43, 122.46, 121.45, 119.33.

(22) IV, C.sub.14H.sub.12ClN.sub.3O.sub.2, M=289.7, 1-(3-chlorophenyl)-3-(phenylcarbamoyl)urea

(23) MS (ESI): m/z (%)=290.1 (100) [M+H].sup.+.

(24) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=9.88 (1H, s), 9.63 (1H, s), 9.16 (1H, s), 7.75-7.75 (1H, m), 7.50-7.48 (2H, m), 7.36-7.31 (4H, m), 7.13-7.11 (1H, m), 7.09-7.06 (1H, m).

(25) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=151.91 (NHCONH), 151.84 (NHCONH), 139.38, 137.76, 133.28, 130.47, 128.90, 123.39, 122.99, 119.32, 118.77, 117.78.

(26) V, C.sub.14H.sub.12ClN.sub.3O.sub.2, M=289.7, 1-(4-chlorophenyl)-3-(phenylcarbamoyl)urea

(27) MS (ESI): m/z (%)=290.0 (100) [M+H].sup.+.

(28) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=9.81 (1H, s), 9.65 (1H, s), 9.11 (1H, s), 7.53-7.52 (2H, m), 7.49-7.47 (2H, m), 7.38-7.36 (2H, m), 7.34-7.31 (2H, m), 7.09-7.06 (1H, m).

(29) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=151.88 (NHCONH), 151.85 (NHCONH), 137.75, 136.81, 128.86, 128.70, 126.97, 123.33, 120.87, 119.28.

(30) VII, C.sub.16H.sub.15N.sub.3O.sub.3, M=285.3, 1-(4-methoxyphenyl)-3-(phenylcarbamoyl)urea

(31) MS (ESI): m/z (%)=284.1 (100) [M−H].sup.−.

(32) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=9.73 (1H, s), 9.51 (1H, s), 9.00 (1H, s), 7.49-7.48 (2H, m), 7.40-7.38 (2H, m), 7.34-7.31 (2H, m), 7.08-7.05 (1H, m), 6.91-6.90 (2H, m), 3.73 (3H, s).

(33) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=155.47, 152.05 (NHCONH), 152.00 (NHCONH), 137.90, 130.73, 128.89, 123.24, 121.17, 119.22, 114.07, 55.17 (OCH3).

(34) VII, C.sub.16H.sub.15N.sub.3O.sub.3, M=297.3, 1-(4-acetylphenyl)-3-(phenylcarbamoyl) urea

(35) MS (ESI): m/z (%)=298.1 (100) [M+H].sup.+.

(36) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.05 (1H, 9), 9.63 (1H, s), 9.18 (1H, s), 7.94-7.92 (2H, m), 7.63-7.61 (2H, m), 7.50-7.48 (2H, m), 7.35-7.32 (2H, m), 7.09-7.06 (1H, m), 2.52 (3H, s).

(37) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=196.29 (COCH.sub.3), 151.81 (NHCONH), 151.76 (NHCONH), 142.29, 137.70, 131.75, 129.51, 128.87, 123.41, 119.34, 118.34, 26.29 (CH.sub.3).

(38) VIII, C.sub.14H.sub.12N.sub.4O.sub.4, M=300.3, 1-(4-nitrophenyl)-3-(phenylcarbamoyl)urea

(39) MS (ESI): m/z (%)=301.0 (100) [M+H].sup.+.

(40) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.37 (1H, s), 9.65 (1H, s), 9.33 (1H, s), 8.20-8.18 (2H, m), 7.74-7.72 (2H, m), 7.49-7.47 (2H, m), 7.34-7.31 (2H, m), 7.09-7.06 (1H, m).

(41) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=151.76 (NHCONH), 151.70 (NHCONH), 144.31, 142.19, 137.65, 128.89, 124.95, 123.48, 119.36, 118.76.

(42) IX, C.sub.16H.sub.16N.sub.3O.sub.4, M=313.3, methyl 4-[(phenylcarbamoyl)ureido]benzoate

(43) MS (ESI): m/z (%)=314.1 (100) [M+H].sup.+.

(44) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.24 (1H, s), 9.82 (1H, s), 9.33 (1H, s), 7.93-7.91 (2H, m), 7.64-7.62 (2H, m), 7.50-7.49 (2H, m), 7.34-7.31 (2H, m), 7.09-7.06 (1H, m), 3.81 (3H, s).

(45) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=165.72 (COO), 151.88 (NHCONH), 151.82 (NHCONH), 142.48, 137.79, 130.39, 128.90, 123.94, 123.38, 119.29, 118.43, 51.83 (CH.sub.3).

(46) X, C.sub.17H.sub.17N.sub.3O.sub.4, M=327.3, ethyl 2-[(phenylcarbamoyl)ureido]benzoate

(47) MS (ESI): m/z (%)=328.1 (23) [M+H].sup.+, 350.0 (100) [M+Na].sup.+.

(48) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=11.21 (1H, s), 9.49 (1H, s), 9.38 (1H, s), 8.30-8.28 (1H, m), 7.94-7.93 (1H, m), 7.60-7.57 (1H, m), 7.49-7.47 (2H, m), 7.35-7.32 (2H, m), 7.19-7.16 (1H, m), 7.09-7.06 (1H, m), 4.36 (2H, d, J=7.1 Hz), 1.35 (3H, d, J=7.1 Hz).

(49) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=166.05 (COO), 151.82 (NHCONH), 151.69 (NHCONH), 139.01, 137.94, 133.35, 130.50, 128.84, 123.17, 122.75, 121.89, 119.10, 118.24, 61.01 (CH.sub.2), 13.93 (CH.sub.3).

(50) XI, C.sub.21H.sub.17N.sub.3O.sub.4, M=375.4, phenyl 4-[(phenylcarbamoyl)ureido]benzoate

(51) MS (ESI): m/z (%)=374.0 (100) [M−H].sup.−.

(52) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.14 (1H, s), 9.64 (1H, s), 9.23 (1H, s), 8.11-8.10 (2H, m), 7.73-7.71 (2H, m), 7.52-7.50 (2H, m), 7.48-7.45 (2H, m), 7.36-7.33 (2H, m), 7.32-7.29 (1H, m), 7.28-7.26 (2H, m), 7.10-7.07 (1H, m).

(53) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=164.00 (COO), 151.78 (NHCONH), 150.65, 143.05, 137.68, 131.09, 129.42, 128.88, 125.77, 123.43, 123.15, 121.84, 119.35, 118.58.

(54) XII, C.sub.21H.sub.17N.sub.3O.sub.4, M=375.4, 3-[(phenylcarbamoyl)ureido]phenyl benzoate

(55) MS (ESI): m/z (%)=374.1 (100) [M−H].sup.−.

(56) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=9.91 (1H, s), 9.70 (1H, s), 9.19 (1H, s), 8.15-8.14 (2H, m), 7.76-7.73 (1H, m), 7.62-7.59 (3H, m), 7.51-7.49 (2H, m), 7.43-7.40 (1H, m), 7.35-7.31 (3H, m), 7.08-7.06 (1H, m), 7.02-7.00 (1H, m).

(57) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=164.41 (COO), 151.96 (NHCONH), 151.88 (NHCONH), 150.92, 139.03, 137.79, 133.94, 129.71, 128.87, 128.85, 123.32, 119.29, 116.67, 116.59, 112.70.

(58) III, C.sub.21H.sub.19N.sub.3O.sub.5S, M=425.5, 3-[(phenylcarbamoyl)ureido]phenyl 4-tolylsulfonate

(59) MS (ESI): m/z (%)=424.0 (100) [M−H].sup.−.

(60) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=9.87 (1H, s), 9.62 (1H, s), 9.11 (1H, s), 7.77-7.75 (2H, m), 7.49-7.46 (4H, m), 7.43-7.43 (1H, m), 7.35-7.29 (4H, m), 7.09-7.06 (1H, m), 6.69-6.67 (1H, m), 2.41 (3H, s).

(61) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=151.78 (NHCONH), 151.77 (NHCONH), 149.27, 145.69, 139.26, 137.70, 131.48, 130.13, 130.08, 128.87, 128.11, 123.39, 119.32, 117.81, 116.31, 112.64, 21.09 (CH.sub.3).

(62) XIV, C.sub.21H.sub.19N.sub.3O.sub.5S, M=425.5, 4-[(phenylcarbamoyl)ureido]phenyl 4-tolylsulfonate

(63) MS (ESI): m/z (%)=424.1 (100) [M−H].sup.−.

(64) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=9.80 (1H, s), 9.63 (1H, s), 9.10 (1H, s), 7.73-7.72 (2H, m), 7.48-7.45 (6H, m), 7.34-7.31 (2H, m), 7.08-7.05 (1H, m), 6.99-6.97 (2H, m), 2.41 (3H, s).

(65) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=151.88 (NHCONH), 151.83 (NHCONH), 145.62, 144.30, 137.73, 136.86, 131.37, 130.10, 128.86, 128.15, 123.34, 122.52, 120.35, 119.26, 21.08 (CH.sub.3).

(66) XV, C.sub.21H.sub.19N.sub.3O.sub.5S, M=425.5, 4-tolyl 3-[(phenylcarbamoyl)ureido]phenylsulfonate

(67) MS (ESI): m/z (%)=424.0 (100) [M−H].sup.−.

(68) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.09 (1H, s), 9.59 (1H, s), 9.23 (1H, s), 8.26-8.25 (1H, m), 7.74-7.72 (1H, m), 7.60-7.57 (1H, m), 7.51-7.49 (3H, m), 7.35-7.31 (2H, m), 7.18-7.16 (2H, m), 7.10-7.06 (1H, m), 6.94-6.91 (2H, m), 2.26 (3H, s).

(69) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=151.97 (NHCONH), 151.73 (NHCONH), 146.85, 139.09, 137.69, 136.90, 135.12, 130.27, 130.24, 128.85, 125.10, 123.42, 122.61, 121.62, 119.37, 117.87, 20.25 (CH.sub.3).

(70) XVI, C.sub.21H.sub.19N.sub.3O.sub.5S, M=425.5, 4-tolyl 4-[(phenylcarbamoyl)ureido]phenylsulfonate

(71) MS (ESI): m/z (%)=424.0 (100) [M−H].sup.−.

(72) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.23 (1H, s), 9.60 (1H, s), 9.28 (1H, s), 7.79-7.74 (4H, m), 7.50-7.49 (2H, m), 7.35-7.32 (2H, m), 7.16-7.15 (2H, m), 7.10-7.07 (1H, m), 6.90-6.89 (2H, m), 2.25 (3H, s).

(73) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=151.79 (NHCONH), 151.70 (NHCONH), 146.91, 143.68, 137.62, 136.74, 130.21, 129.66, 128.88, 127.74, 123.48, 121.70, 119.37, 118.97, 20.25 (CH.sub.3).

(74) XVII, C.sub.17H.sub.15N.sub.5O.sub.4S.sub.2, M=417.5, 1-(4-sulfathiazolylphenyl)-3-(phenyl-carbamoyl)urea

(75) MS (ESI): m/z (%)=416.0 (100) [M−H].sup.−.

(76) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.06 (1H, s), 9.76 (1H, s), 9.48 (1H, s), 7.77-7.75 (2H, m), 7.62-7.60 (2H, m), 7.51-7.49 (2H, m), 7.34-7.31 (2H, m), 7.16 (1H, d, J=4.3 Hz), 7.08-7.06 (1H, m), 6.70 (1H, d, J=4.3 Hz).

(77) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=169.08, 151.97 (NHCONH), 151.91 (NHCONH), 140.61, 137.81, 137.77, 128.90, 128.90, 127.08, 123.40, 119.42, 118.65, 107.86.

(78) XVIII, C.sub.19H.sub.18N.sub.6O.sub.4S, M=426.4, (2-(4-methyl-pyrimidyl)) 4-[(phenyl-carbamoyl)ureido]phenylsulfonamide

(79) MS (ESI): m/z (%)=425.0 (100) [M−H].sup.−.

(80) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.41 (1H, s), 10.00 (1H, bs), 9.94 (1H, s), 9.44 (1H, s), 8.32 (1H, d, J=5.1 Hz), 7.97-7.95 (2H, m), 7.68-7.67 (2H, m), 7.49-7.48 (2H, m), 7.33-7.30 (2H, m), 7.08-7.05 (1H, m), 6.89 (1H, d, J=5.1 Hz), 2.31 (3H, s).

(81) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=168.20, 157.42, 156.51, 151.94 (NHCONH), 151.83 (NHCONH), 141.95, 137.80, 134.32, 129.18, 128.89, 123.37, 119.28, 118.24, 114.77, 23.21 (CH.sub.3).

(82) XIX, C.sub.18H.sub.15N.sub.3O.sub.2, M=305.3, 1-(1-naphthyl)-3-(phenylcarbamoyl)urea

(83) MS (ESI): m/z (%)=304.1 (100) [M−H].sup.−.

(84) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=9.84 (3H, bs), 8.09-8.05 (2H, m), 7.97-7.95 (1H, m), 7.73-7.71 (1H, m), 7.65-7.62 (1H, m), 7.58-7.50 (4H, m), 7.37-7.34 (2H, m), 7.11-7.08 (1H, m).

(85) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=152.77 (NHCONH), 152.42 (NHCONH), 137.87, 133.60, 132.76, 128.87, 128.46, 126.29, 126.01, 125.84, 125.69, 124.04, 123.29, 120.65, 119.35, 118.06.

(86) XX, C.sub.11H.sub.10N.sub.4O.sub.2S, M=262.3, 1-(2-thiazolyl)-3-(phenylcarbamoyl)urea

(87) MS (ESI): m/z (%)=263.0 (44) [M+H].sup.+, 170.0 (100) [M-ArNH3].sup.+.

(88) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=11.32 (1H, s), 9.62 (1H, s), 9.43 (1H, s), 7.51-7.49 (2H, m), 7.45-7.44 (1H, m), 7.35-7.32 (2H, m), 7.22-7.21 (1H, m), 7.11-7.08 (1H, m).

(89) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=158.42, 151.80 (NHCONH), 151.49 (NHCONH), 137.51, 136.99, 128.86, 123.55, 119.49, 113.57.

(90) XXI, C.sub.15H.sub.12N.sub.4O.sub.2S, M=312.3, 1-(2-benzothiazolyl)-3-(phenylcarbamoyl)urea

(91) MS (ESI): m/z (%)=313.0 (100) [M+H].sup.+.

(92) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=11.54 (1H, bs), 9.81 (1H, s), 9.74 (1H, s), 7.97-7.95 (1H, m), 7.71-7.70 (1H, m), 7.53-7.51 (2H, m), 7.45-7.42 (1H, m), 7.37-7.34 (2H, m), 7.32-7.29 (1H, m), 7.13-7.09 (1H, m).

(93) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=151.47 (NHCONH), 151.47 (NHCONH), 149.66, 144.41, 142.92, 137.50, 128.88, 126.17, 126.05, 123.60, 123.44, 121.68, 119.50.

(94) XXII, C.sub.13H.sub.12N.sub.4O.sub.2, M=256.3, 1-(2-pyridyl)-3-(phenylcarbamoyl)urea

(95) MS (ESI): m/z (%)=254.9 (100) [M−H].sup.−.

(96) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.07 (3H, bs), 8.31-8.30 (1H, m), 7.82-7.78 (1H, m), 7.76-7.75 (1H, m), 7.51-7.49 (2H, m), 7.35-7.32 (2H, m), 7.11-7.06 (2H, m).

(97) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=152.17, 151.50 (NHCONH), 151.35 (NHCONH), 147.54, 138.59, 137.73, 128.88, 123.40, 119.36, 118.98, 112.67.

(98) XXIII, C.sub.13H.sub.12N.sub.4O.sub.2, M=256.3, 1-(4-pyridyl)-3-(phenylcarbamoyl)urea

(99) MS (ESI): m/z (%)=255.1 (77) [M−H].sup.−.

(100) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.05 (1H, s), 9.59 (1H, s), 9.25 (1H, s), 8.44-8.43 (2H, m), 7.50-7.48 (4H, m), 7.35-7.32 (2H, m), 7.10-7.07 (1H, m).

(101) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=151.81 (NHCONH), 151.69 (NHCONH), 150.30, 144.78, 137.61, 128.85, 123.46, 119.39, 113.21.

(102) XXIV, C.sub.18H.sub.17N.sub.3O, M=339.3, 1-(4-acetylphenyl)-3-(4-acetylphenyl-carbamoyl)urea

(103) MS (ESI): m/z (%)=338.1 (100) [M−H].sup.−.

(104) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.35-8.94 (3H, m), 7.94-7.92 (4H, m), 7.63-7.61 (4H, m), 2.52 (6H, s).

(105) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=196.30 (COCH.sub.3), 151.68 (NHCONH), 142.19, 131.81, 129.49, 118.39, 26.29 (CH.sub.3).

(106) XXV, C.sub.23H.sub.21N.sub.3O.sub.6S, M=467.5, 3-[(4-acetylphenylcarbamoyl)ureido]phenyl 4-tolylsulfonate

(107) MS (ESI): m/z (%)=466.1 (100) [M−H].sup.−.

(108) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.04 (1H, s), 9.87 (1H, s), 9.30 (1H, s), 7.95-7.93 (2H, m), 7.77-7.75 (2H, m), 7.64-7.62 (2H, m), 7.48-7.47 (2H, m), 7.43-7.43 (2H, m), 7.31-7.30 (1H, m), 6.69-6.67 (1H, m), 2.53 (3H, s), 2.41 (3H, s).

(109) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=196.31 (COCH.sub.3), 151.68 (NHCONH), 151.63 (NHCONH), 149.26, 145.69, 142.22, 139.17, 131.80, 131.47, 130.13, 130.07, 129.50, 128.10, 118.38, 117.87, 116.39, 112.70, 26.31 (CH.sub.3), 21.09 (CH.sub.3).

(110) XXVI, C.sub.23H.sub.21N.sub.3O.sub.6S, M=467.5, 4-tolyl 4-[(4-acetylphenylcarbamoyl)ureido]phenylsulfonate

(111) MS (ESI): m/z (%)=466.1 (100) [M−H].sup.−.

(112) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.14 (1H, s), 9.93 (1H, s), 9.39 (1H, s), 7.95-7.93 (2H, m), 7.79-7.74 (4H, m), 7.64-7.62 (2H, m), 7.17-7.15 (2H, m), 6.91-6.88 (2H, m), 2.52 (3H, s), 2.25 (3H, s).

(113) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=196.31 (COCH.sub.3), 151.66 (NHCONH), 151.52 (NHCONH), 146.90, 143.57, 142.10, 136.76, 131.90, 130.21, 129.65, 129.50, 127.86, 121.70, 119.05, 118.46, 26.31 (CH.sub.3), 20.25 (CH.sub.3).

(114) XXVII, C.sub.22H.sub.21N.sub.3O.sub.6S, M=455.5, 4-tolyl 4-[(4-methoxyphenylcarbamoyl)ureido]phenylsulfonate

(115) MS (ESI): m/z (%)=454.0 (100) [M−H].sup.−.

(116) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.25 (1H, s), 9.40 (1H, s), 9.22 (1H, s), 7.79-7.73 (4H, m), 7.40-7.38 (2H, m), 7.17-7.15 (2H, m), 6.92-6.89 (4H, m), 3.73 (3H, s), 2.26 (3H, s).

(117) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=155.59, 151.80 (NHCONH), 151.78 (NHCONH), 146.89, 143.71, 136.72, 130.47, 130.19, 129.63, 127.66, 121.66, 121.27, 118.90, 114.05, 55.15 (OCH.sub.3), 20.23 (CH.sub.3).

(118) XXVIII, C.sub.21H.sub.18ClN.sub.3O.sub.5S, M=459.9, 4-tolyl 4-[(3-chlorophenylcarbamoyl)ureido]phenylsulfonate

(119) MS (ESI): m/z (%)=458.0 (100) [M−H].sup.−.

(120) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=10.27 (1H, s), 9.87 (1H, s), 9.43 (1H, s), 7.79-7.74 (5H, m), 7.35-7.34 (2H, m), 7.17-7.15 (2H, m), 7.13-7.11 (1H, m), 6.90-6.88 (2H, m), 2.25 (3H, s).

(121) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=151.67 (NHCONH), 151.65 (NHCONH), 146.88, 143.62, 139.18, 136.71, 133.23, 130.41, 130.18, 129.61, 127.79, 123.10, 121.66, 118.96, 118.83, 117.82, 20.23 (CH.sub.3).

(122) XXIX, C.sub.22H.sub.20N.sub.6O.sub.4, M=432.4, N,N′-1,4-phenylene-bis[N″-phenylcarbamoylurea]

(123) MS (ESI): m/z (%)=431.1 (100) [M−H].sup.−.

(124) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): δ (ppm)=9.70 (2H, s), 9.65 (2H, s), 9.03 (2H, s), 7.50-7.46 (8H, m), 7.34-7.31 (4H, m), 7.09-7.06 (2H, m).

(125) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): δ (ppm)=151.92 (NHCONH), 137.82, 133.37, 128.84, 123.25, 119.98, 119.23.

(126) The heat-sensitive recording materials according to the invention were produced as follows, with non-phenolic colour developers of the prior art being used as comparison colour developers, namely N-(2-(3-phenylureido)phenyl)benzenesulfonamide (comparison example Vb) and a sulfonylurea, Pergafast® 201, BASF (PF201) (comparison example PF201):

(127) An aqueous coating suspension was applied to one side of a 63 g/m.sup.2 synthetic base paper (Yupo® FP680) using a doctor blade on a laboratory scale to form the heat-sensitive colour-forming layer of a heat-sensitive recording paper. After drying, a thermal recording sheet was obtained. The application rate of the heat-sensitive colour-forming layer was between 3.8 and 4.2 g/m.sup.2.

(128) On the basis of the above information, a heat-sensitive recording material or thermal paper was produced, with the following formulations of aqueous application suspensions being used to form a composite structure on a carrier substrate, and then the other layers, especially a protective layer, being formed in the usual manner, which will not be discussed separately here.

(129) Production of the dispersions (in each case for 1 part by weight) for the application suspensions:

(130) The aqueous dispersion A (colour former dispersion) is produced by grinding 20 parts by weight of 3-N-n-dibutylamino-6-methyl-7-anilinofluoran (ODB-2) with 33 parts by weight of a 15% aqueous solution of Ghosenex™ L-3266 (sulfonated polyvinyl alcohol, Nippon Ghosei) in a bead mill.

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

(132) The aqueous dispersion C (sensitising agent dispersion) is produced by grinding 40 parts by weight of sensitising agent with 33 parts by weight of a 15% aqueous solution of Ghosenex™ L-3266 in a bead mill.

(133) All dispersions produced by grinding have an average particle size D.sub.(4.3) of 0.80-1.20 μm. The particle size distribution of the dispersions was measured by laser diffraction using a Coulter LS230 instrument from Beckman Coulter.

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

(135) Pigment P is a 72 coating kaolin suspension (Lustra® S, BASF).

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

(137) The heat-sensitive application suspension is produced by mixing, with stirring, 1 part of dispersion A, 1 part of dispersion B, 1 part of dispersion C, 56 parts of dispersion D, 146 parts of pigment P and 138 parts of binder solution (all parts by weight), taking into account the order of introduction B, C, D, P, A, binder, and bringing the mixture to a solids content of about 25% with water.

(138) The heat-sensitive coating suspensions obtained in this way were used to produce composite structures consisting of paper carrier and heat-sensitive colour-forming layer.

(139) The heat-sensitive recording materials according to the invention were evaluated as shown below (Tables 3 and 4)

(140) (1) Dynamic Colour Density:

(141) The papers (6 cm wide strips) were thermally printed with a chessboard pattern with 10 energy levels using an Atlantek 200 test printer (Atlantek, USA) with a Kyocera print bar of 200 dpi and 560 ohms at an applied voltage of 20.6 V and a maximum pulse width of 0.8 ms. The image density (optical density, o. d.) was measured with a SpectroEye densitometer from X-Rite at an energy level of 0.45 mJ/dot. The measurement uncertainty of the o. d. values is estimated at ≤2%.

(142) (2) Static Colour Density (Starting Temperature):

(143) The recording sheet was pressed against a series of thermostatically controlled metallic stamps heated to different temperatures with a contact pressure of 0.2 kg/cm.sup.2 and a contact time of 5 seconds (thermal tester TP 3000QM, Maschinenfabrik Hans Rychiger AG, Steffisburg, Switzerland). The image density (opt. density) of the images thus produced was measured with a SpectroEye densitometer from X-Rite.

(144) The static starting point is, by definition, the lowest temperature at which an optical density of 0.2 is achieved. The accuracy of the measuring method is ≤±0.5° C.

(145) (3) Resistance Test of the Printed Image Under Artificial Ageing Conditions:

(146) Samples of the thermal recording paper dynamically recorded according to the process of (1) were stored for 7 days under one each of the following conditions:

(147) i) 50° C. (dry ageing),

(148) ii) 40° C., 85% relative humidity (humidity ageing) and

(149) iii) under artificial light from fluorescent tubes, illuminance 16000 lux (light ageing).

(150) At the end of the test period, the image density was measured at a current energy of 0.45 mJ/dot and set in relation to the corresponding image density values before artificial ageing in accordance with the formula (Eq. 1).

(151) $\begin{array}{cc}\%\mathrm{remaining}\mathrm{image}\mathrm{density}=\left(\frac{\mathrm{image}\mathrm{density}\mathrm{after}\mathrm{test}}{\mathrm{image}\mathrm{density}\mathrm{before}\mathrm{test}}\right)*100& \left(\mathrm{Eq}.1\right)\end{array}$

(152) The spread of the % values calculated according to (Eq. 1) is ≤±2 percentage points.

(153) (4) Shelf Life of the Unprinted Thermal Paper:

(154) A sheet of recording paper was cut into three identical strips. One strip was dynamically recorded according to the process of (1) and the image density was determined. The other two strips were stored in the unprinted (white) state for 4 weeks in a climate of a) 40° C. and 85% relative humidity (r. h.) and b) 60° C. and 50% relative humidity (r. h.).

(155) After conditioning the papers at room temperature, they were dynamically printed according to the process of (1) and the image density was determined using a densitometer at a current energy of 0.45 mJ/dot. The remaining writing power (%) of the stored to fresh (not aged) samples was calculated according to equation (Eq. 1).

(156) Tables 3 and 4 summarise the evaluation of the heat-sensitive recording materials produced.

(157) TABLE-US-00003 TABLE 3 Image density, starting temperature and artificial ageing; o.d. Starting Colour (0.45 point Artificial ageing* developer mJ/dot) (° C.) dry moist light VII 1.28 86 100 98 84 XXV 1.22 89 100 97 71 XXVI 1.23 84 100 98 77 XXVIII 1.24 90 100 99 74 Comparison 1.24 82 98 98 76 example Vb Comparison 1.22 78 98 97 73 example PF201 *remaining % image density (o.d.), (according to Eq. 1)

(158) TABLE-US-00004 TABLE 4 Writing performance after storage; 4 weeks 40° C./85% r.h. 4 weeks 60° C./50% r.h. o.d. o.d. Remaining o.d. Remaining Colour before after o.d. after o.d. developer storage storage (%)* storage (%)* VIII 1.28 1.26 98.4 1.14 89.1 XXV 1.22 1.20 98.4 1.11 91.0 XXVI 1.23 1.20 97.6 1.10 89.4 XXVIII 1.24 1.27 102.4 1.10 88.7 Comparison 1.24 1.26 101.6 1.04 83.9 example Vb Comparison 1.22 1.20 98.4 0.81 66.4 example PF201 *according to Eq. 1

(159) The heat-sensitive recording material according to the invention shows the following advantageous properties especially:

(160) (1) The recorded image of the heat-sensitive recording materials according to the invention with the colour developers (A) has a print density (optical density) comparable to that of the colour developers of the comparison samples (Table 3).

(161) (2) The temperature from which a visually perceptible greying of the heat-sensitive recording materials according to the invention occurs (static starting point) is higher than that of the comparison papers and largely meets the requirements for marketable heat-sensitive recording materials (Table 3).

(162) (3) The heat-sensitive recording materials subjected to the ageing test reveal a high image stability, better or comparable to the comparison papers (Table 3).

(163) (4) Printing on the heat-sensitive recording materials according to the invention stored for several weeks under extreme conditions results in image densities that are practically identical to those of unstored (fresh) heat-sensitive recording materials (Table 4).

(164) (5) With the colour developers of formula (A), a heat-sensitive recording material of high quality in all of the important application-related aspects can be obtained, and no thermal paper obtained with prior-art colour developers has a comparable good performance profile with regard to all properties.