Thermal recording material
View Patent ↗The present invention provides a heat-sensitive recording material comprising a substrate and a heat-sensitive recording layer provided thereon, the layer comprising a color forming system that combines an electron-donating colorless dye and an electron-accepting compound, in which the electron-accepting compound is a compound represented by the formula R 1 -Ph-SO 2 R 2 (wherein R 1 represents a hydroxyl group or an alkyl group, R 2 represents -Ph, —NH-Ph, -Ph-OR 3 or —NH—CO—NH-Ph, R 3 represents an alkyl group, and Ph represents a phenyl group), and at least the heat-sensitive recording layer is formed by curtain-coating a coating solution for the heat-sensitive recording layer.
1. A heat-sensitive recording material comprising a substrate and a heat-sensitive recording layer provided thereon, the layer comprising an electron-donating colorless dye and an electron-accepting compound that reacts with the electron-donating colorless dye to develop color,
wherein the electron-accepting compound is 4-hydroxybenzenesulfoanilide, and
at least the heat-sensitive recording layer is formed by curtain-coating a coating solution for the heat-sensitive recording layer.
2. A heat-sensitive recording material according to claim 1 , wherein the viscosity of the coating solution is 30 to 300 mPa·s.
3. A heat-sensitive recording material according to claim 2 , wherein the heat-sensitive recording layer is formed by coating the coating solution in an amount of 5 g/m 2 or less.
4. A heat-sensitive recording material according to claim 2 , wherein the surface tension of the coating solution is 25 to 50 mN/m.
5. A heat-sensitive recording material according to claim 2 , wherein a protective layer is provided on the heat-sensitive layer, and the protective layer contains at least one inorganic pigment selected from aluminum hydroxide, kaolin and amorphous silica, and a water-soluble polymer.
6. A heat-sensitive recording material according to claim 2 , wherein the heat-sensitive recording layer comprises a sensitizer, and the sensitizer is at least one compound selected from 2-benzyloxynaphthalene, dimethylbenzyl oxalate, m-terphenyl, ethyleneglycoltolylether. p-benzylbiphenl, 1,2-diphenoxymethylbenzene, diphenylsulfone and 1,2-diphenoxyethane.
7. A heat-sensitive recording material according to claim 1 , wherein the electron-donating colorless dye is at least one selected from 2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-dibutylaminofluorane, 2-anilino-3-methyl-6-(N-ethyl-N-isoamylamino)fluorane, 2-anilino-3-methyl-6-(N-ethyl-N-propylamino)fluorane, 2-anilino-3-methyl-6-di-n-amylaminofluorane and 2-anilino-3-methyl-6-(N-ethyl-N-p-tolylamino)fluorane.
8. A heat-sensitive recording material according to claim 1 , wherein at least the heat sensitive recording layer is dried at a highest surface temperature of 65° C. or lower during a constant rate drying process.
9. A heat-sensitive recording material according to claim 8 , wherein the heat-sensitive recording layer comprises a sensitizer, and the sensitizer is at least one compound selected from 2-benzyloxynaphthalene, dimethylbenzyl oxalate, m-terphenyl, ethyleneglycoltolylether. p-benzylbiphenl, 1,2-diphenoxymethylbenzene, diphenylsulfone and 1,2-diphenoxyethane.
10. A heat-sensitive recording material according to claim 8 , wherein the electron-donating colorless dye is at least one selected from 2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-dibutylaminofluorane, 2-anilino-3-methyl-6-(N-ethyl-N-isoamylamino)fluorane, 2-anilino-3-methyl-6-(N-ethyl-N-propylamino)fluorane, 2-anilino-3-methyl-6-di-n-amylaminofluorane and 2-anilino-3-methyl-6-(N-ethyl-N-p-tolylamino)fluorane.
11. The heat-sensitive recording material according to claim 1 , wherein the coating solution is coated at a coating speed of 200 to 2,000 m/minute and a falling speed of the coating solution in the form of a film at the coating point is at a ratio of 1/40 to 1 of the coating speed.
12. A heat-sensitive recording material according to claim 11 , wherein the heat-sensitive recording layer comprises a sensitizer, and the sensitizer is at least one compound selected from 2-benzyloxynaphthalene, dimethylbenzyl oxalate, m-terphenyl, ethyleneglycoltolylether. p-benzylbiphenl, 1,2-diphenoxymethylbenzene, diphenylsulfone and 1,2-diphenoxyethane.
13. A heat-sensitive recording material according to claim 11 , wherein the electron-donating colorless dye is at least one selected from 2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-dibutylaminofluorane, 2-anilino-3-methyl-6-(N-ethyl-N-isoamylamino)fluorane, 2-anilino-3-methyl-6-(N-ethyl-N-propylamino)fluorane, 2-anilino-3-methyl-6-di-n-amylaminofluorane and 2-anilino-3-methyl-6-(N-ethyl-N-p-tolylamino)fluorane.
14. A heat-sensitive recording material according to claim 1 , wherein the central line average roughness (R a75 ) at the surface of the heat sensitive recording layer is 2.0 μm or less.
15. A heat-sensitive recording material according to claim 14 , wherein the central line average roughness (R a75 ) at the surface of the heat sensitive recording layer is from 0.5 μm to 2.0 μm or less.
16. The heat-sensitive recording material according to claim 14 , wherein the heat sensitive recording layer contains an inorganic pigment that is at least one selected from calcite-structured (light) calcium carbonate, amorphous silica and aluminum hydroxide.
17. The heat-sensitive recording material according to claim 14 , wherein the support contains waste paper pulp.
18. The heat-sensitive recording material according to claim 14 , wherein the heat-sensitive recording material has a protective layer thereon, and the protective layer contains at least one inorganic pigment selected from aluminum hydroxide, kaolin and amorphous silica, in combination with a water-soluble polymer.
19. The heat-sensitive recording material according to claim 14 , wherein the heat sensitive recording layer contains a sensitizer that is at least one selected from 2-benzyloxynaphthalene, dimethylbenzyl oxalate, m-terphenyl, ethyleneglycol tolylether, p-benzyl biphenyl, 1,2-diphenoxymethylbenzene, diphenyl sulfone and 1,2-diphenoxyethane.
20. The heat-sensitive recording material according to claim 14 , wherein the electron-donating colorless dye is at least one selected from 2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-dibutylaminofluorane, 2-anilino-3-methyl-6-(N-ethyl-N-isoamylamino)fluorane, 2-anilino-3-methyl-6-(N-ethyl-N-propylamino)fluorane, 2-anilino-3-methyl-6-di-n-amylaminofluorane and 2-anilino-3-methyl-6-(N-ethyl-N-p-tolylamino)fluorane.