JP2009241414A - Thermal recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal recording material capable of obtaining a colored image by causing reaction of dye precursors and electron-accepting color developers with each other by heating with a thermal head, which has an excellent ink ribbon thermal transfer receiving property and achieving multi-color development as well. <P>SOLUTION: The thermal recording material has a thermal recording layer and a protection layer mounted in series on the support body, wherein the thermal recording layer contains normally colorless or light-colored electron donative dye precursors and electron accepting compounds developing color of the dye precursors by reaction caused when being heated. At least either one of hollow resin particles, bowl-shaped resin particles and hollow resin particles having through-bores therein is included in the thermal recording layer, in addition, two or more precursors developing colors in different tones from each other are included as the dye precursors, and at least one precursor is present as particles having a coloring adjustment layer on the surface thereof. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat-sensitive recording material having excellent ink ribbon thermal transfer acceptability.

  The heat-sensitive recording material generally comprises a support on which a heat-sensitive recording layer mainly comprising an electron-donating usually colorless or light-colored dye precursor and an electron-accepting developer is provided. By heating with a laser beam, etc., the dye precursor and the electron-accepting developer react instantaneously to obtain a color image, the recording device is simple and easy to maintain, no noise is generated, etc. Because of its advantages, it is used in a wide range of fields such as measurement recorders, facsimiles, POS printers, ATM / CDs, label machines and the like. Also, in the ticket issuance field such as tickets and lotteries, the so-called thermal transfer recording method in which an ink ribbon is heated with a thermal head and melted and transferred to a recording medium has been conventionally performed. The adoption of thermal recording methods is also increasing for reasons such as unnecessary. As a result, there are cases where these two types of ticket issuance recording apparatuses are operated in combination with a thermal recording system and a thermal transfer recording system. In this case, the thermal recording system and the thermal transfer recording are performed on the same recording surface. There is a need for a recording material that can be used for both recording methods. In particular, the recent thermal transfer recording system has shifted the type of ink ribbon from the wax type to the resin type in order to obtain high image reliability, but in the case of the resin type, compared to the wax type in order to obtain high image quality, Higher thermal transfer acceptability is required for recording materials. Furthermore, in the ticket issuing field, the demand for multicolored coloring is increasing as the operating methods are expanding.

Up to now, as a method for performing two recordings, thermal recording and thermal transfer recording, on the same recording surface of the thermal recording material, a method of making the recording surface highly smooth (for example, see Patent Document 1) has been proposed. However, even with high smoothness, sufficient performance cannot be obtained for these two recording methods. Further, when a known thermal transfer receiving layer (see, for example, Patent Document 2, Patent Document 3, and Patent Document 4) is provided on the thermal recording layer, the thermal transfer performance is excellent, but the color development sensitivity and the anti-sticking property as the thermal recording performance. Remarkably deteriorates.
JP 7-186543 A JP-A-57-182487 JP-A-8-183262 JP-A-11-105440

  The present invention is a heat-sensitive recording material in which a dye precursor and an electron-accepting developer react with each other by heating with a thermal head or the like, and has excellent ink ribbon thermal transfer acceptability. It is an object of the present invention to provide a thermosensitive recording material capable of obtaining color development.

  As a result of repeated studies, the present inventors have invented the heat-sensitive recording material of the present invention that can solve the problems. That is, a heat-sensitive recording layer and a protective layer containing an electron-accepting compound that reacts with an electron-donating ordinary colorless or light-colored dye precursor upon heating to develop a color of the dye precursor are provided on the support. In the recording material, the thermosensitive recording layer contains at least one of hollow resin particles, bowl-shaped resin particles, and hollow resin particles having through-holes, and further has different color tones as the dye precursor. It was achieved by containing two or more kinds that develop color, and at least one kind is present in the form of particles having a color development controlling layer on the surface.

  A heat-sensitive recording material comprising, on a support, a heat-sensitive recording layer and an electron-accepting compound that reacts with an electron-donating ordinary colorless or light-colored dye precursor upon heating to develop a color of the dye precursor, and a protective layer. In the heat-sensitive recording layer, at least one of hollow resin particles, bowl-shaped resin particles, and hollow resin particles having through-holes is contained in the heat-sensitive recording layer, so that the heat-sensitive recording having excellent ink ribbon thermal transfer acceptability. In addition, the dye precursor contains two or more kinds that develop colors different from each other, and at least one kind is present in the form of particles having a color forming control layer on the surface, It is possible to provide a multicolor thermosensitive recording material excellent in separability.

  The contents of the present invention will be specifically described below. The heat-sensitive recording material of the present invention contains at least one of hollow resin particles, bowl-shaped resin particles, and hollow resin particles having through holes in the heat-sensitive recording layer, and is otherwise known in the heat-sensitive recording material field. A heat-sensitive recording layer containing an electron-donating dye precursor, an electron-accepting developer, an adhesive, a white pigment, an image preservative, and the like, and an adhesive, a white pigment, and the like as necessary. The protective layers are sequentially formed on the support. In this specification, “hollow resin particles” refer to resin particles having a closed space inside the particles, and “saddle-shaped resin particles” are obtained by cutting the hollow resin particles on one plane. The resin particles are referred to as “hollow resin particles having through-holes”, which are resin particles having one or more through-holes connecting the particle surface layer and the internal space, both of which can be observed with an electron microscope or the like.

  The excellent thermal transfer acceptability of the ink ribbon in the present invention contributes to the excellent heat insulation, smoothness, and cushioning properties of the hollow resin particles, bowl-shaped resin particles, and hollow resin particles having through holes contained in the heat-sensitive recording layer. It is thought that. However, for example, when the resin particle is provided with an intermediate layer between the support and the heat-sensitive recording layer and contained in the intermediate layer, the performance of the resin particle is not sufficiently exhibited for the ink ribbon thermal transfer acceptability. . Further, when the resin particles are contained in the protective layer on the thermosensitive recording layer, the protective layer is in direct contact with the heated thermal head during the thermosensitive recording. Sticking performance is significantly reduced. That is, in order to obtain a heat-sensitive recording material having excellent ink ribbon thermal transferability, it is important that the layer containing the resin particles is a heat-sensitive recording layer as in the present invention.

  In the present invention, the hollow resin particles, bowl-shaped resin particles, and hollow resin particles having through-holes to be contained in the heat-sensitive recording layer are not particularly limited, but include vinyl chloride, vinylidene chloride, vinyl acetate, styrene, acrylic acid. A homopolymer mainly composed of monomers such as methyl, ethyl acrylate, butyl acrylate, acrylonitrile, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methacrylonitrile, etc. A copolymer etc. are mentioned. As the size of the resin particles, resin particles having an average particle size of 0.1 to 5.0 μm, more preferably 0.5 to 2.0 μm, as measured by a particle size distribution measurement method using a laser diffraction method can be used. Moreover, as content of these resin particles, it is preferable to contain 3-40 mass% with respect to the whole thermosensitive recording layer. When the amount is less than 3% by mass, the effects of the heat insulating property, smoothness and cushioning properties due to the resin particles are lowered. When the amount is more than 40% by mass, the concealing property by these resin particles is increased, resulting in a decrease in thermal color density.

  As the hollow resin particles in the present invention, particles having a hollow ratio (volume ratio of the space portion to the total volume of the resin portion and the space portion of the particle) of 20 to 90%, more preferably 40 to 90% can be used. For example, Rohm and Haas Japan Co., Ltd. is commercially available as a low-pike series and JSR Co., Ltd. as an SX series. Specifically, Ropaque HP-91 (average particle size 1.0 μm, hollow ratio 51%), Ropaque OP-62 (0.4 μm, 33%), Ropaque OP-84J (0.55 μm, 20). SX8772 (A) (1.1 μm, 55%), SX8782 (D) (1.0 μm, 51%), SX866 (B) (0.3 μm, 30%), etc. be able to.

  As the cage resin particles in the present invention, for example, MH8055 (average particle size 0.8 μm) is commercially available from Nippon Zeon Co., Ltd. and can be obtained. The hollow resin particles having through-holes are commercially available, for example, as Mitsdale TX series from Mitsui Chemicals, Inc., and specifically, Grosdale 2001TX (average particle size 1.0 μm). ), Grosdale 2000TX (0.5 μm).

  In the present invention, in order to obtain a multicolor-colored heat-sensitive recording material, the dye precursor contains two or more types that develop colors different from each other, and at least one or more types are in the form of particles having a color adjusting layer on the surface. It can be used. At this time, the dye precursor existing in the form of particles whose surface is covered with the color adjusting layer is a high temperature coloring dye precursor because the color starting temperature shifts to the high temperature side. A dye precursor having a different color tone and having no color adjusting layer on the surface is a low-temperature color precursor.

  In the present invention, in order to coat the surface of the dye precursor for high-temperature color development, the vinyl monomer and the dispersion liquid of the dye precursor particles previously dispersed by an arbitrary method such as a bead mill or a ball mill are used. A method may be used in which a polymerization initiator is added and, if necessary, heated to perform addition polymerization around the dye precursor particles to form a color adjusting layer. At this time, the particle diameter of the dye precursor particles is preferably 0.1 to 20 μm. As the dispersion medium for the dye precursor particles, an aqueous dispersion medium is preferably used. The aqueous dispersion medium is water or a mixed solution of water and an organic solvent compatible with water. Specific examples of the organic solvent compatible with water include methyl alcohol, ethyl alcohol, isopropyl alcohol, Acetone, methyl ethyl ketone, ethylene glycol and the like can be mentioned, but there is no particular limitation as long as the organic solvent is compatible with water. When the dye precursor particles are dispersed with an aqueous dispersion medium, the dispersion stability is good when the color control layer is formed on the surface of the dye precursor particles by addition polymerization of the vinyl monomer. Aggregation is difficult to occur, and formation of the color adjusting layer is hardly inhibited.

  In the present invention, as the vinyl monomer that is a material for the color adjusting layer, a compound having one or more vinyl bonds can be used, and the content of the compound having two or more vinyl bonds is changed. As a result, the color development sensitivity characteristics of the color development control layer can be freely changed. Compared to those polymerized with only a compound having one vinyl bond, the color-adjusting layer using a compound having two or more vinyl bonds has a stronger cross-linking structure, and has a color development start temperature when it is used as a heat-sensitive recording material. Can be on the high temperature side. The combined ratio of the compound having two or more vinyl bonds is 1 to 70% by mass, preferably 10 to 50% by mass, based on the total mass of the vinyl monomer. Within this range, color development characteristics such as the color development start temperature can be arbitrarily adjusted. The amount of the vinyl monomer with respect to the dye precursor is preferably 0.5 to 2000% by mass. When the amount is within this range, the polymerization proceeds without agglomeration, and the function as the color adjusting layer is sufficiently obtained. As the vinyl monomer, known compounds can be used. Among them, when some or all of them are methacrylic acid esters, the methacrylic acid ester and the polymer are used for adhesion to the dye precursor particles, to the aqueous dispersion medium. Since both the solubility and the addition polymerization property are good, the surface of the dye precursor particles can be efficiently coated, and the function of arbitrarily adjusting the coloring property is excellent, which is preferably used in the present invention.

  In the present invention, a known polymerization initiator can be used for addition polymerization of the vinyl monomer, and the mode of the polymerization reaction is not particularly limited, such as radical polymerization, anionic polymerization, and cationic polymerization. Is particularly preferably used. In the polymerization, the system may be heated as necessary. The addition amount of the polymerization initiator is not particularly limited as long as the vinyl monomer starts addition polymerization, but in order to efficiently start the addition polymerization, the amount of the polymerization initiator is about 0.1%. 001-10 mass% is preferable.

  In the present invention, the color tone when the heat-sensitive recording material for multi-color development is a dark color due to a color mixture at a high temperature with a color tone at a low temperature. The high-temperature color can be selected black. As the electron-donating dye precursor, compounds used for pressure-sensitive recording paper and heat-sensitive recording paper can be used, and one or more dye precursors are used in appropriate combination. Specific examples include the following, but the present invention is not limited thereto.

  Examples of black dye precursors include 3-di-n-butylamino-6-methyl-7-anilinofluorane, 3-di-n-pentylamino-6-methyl-7-anilinofluorane, 3 -Diethylamino-6-methyl-7-anilinofluorane, 3-di-n-butylamino-7- (2-chloroanilino) fluorane, 3-diethylamino-7- (2-chloroanilino) fluorane, 3-diethylamino-6 -Methyl-7-xylidinofluorane, 3-diethylamino-7- (2-carbomethoxyphenylamino) fluorane, 3- (N-cyclohexyl-N-methyl) amino-6-methyl-7-anilinofluorane, 3- (N-cyclopentyl-N-ethyl) amino-6-methyl-7-anilinofluorane, 3- (N-isoamyl-N-ethyl) amino- -Methyl-7-anilinofluorane, 3- (N-ethyl-4-toluidino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-4-toluidino) -6-methyl-7 -(4-Toluidino) fluorane, 3- (N-methyl-N-tetrahydrofurfuryl) amino-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3 -Pyrrolidino-6-methyl-7- (4-n-butylphenylamino) fluorane, 3-piperidino-6-methyl-7-anilinofluorane,

  Examples of red dye precursors include 3,3-bis (1-n-butyl-2-methylindol-3-yl) phthalide and 3,3-bis (1-n-butyl-2-methylindole-3). -Yl) tetrachlorophthalide, 3,3-bis (1-n-butylindol-3-yl) phthalide, 3,3-bis (1-n-pentyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-hexyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-octyl-2-methylindol-3-yl) phthalide, 3,3- Bis (1-methyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-propyl-2-) Methylindol-3-yl) phthali 3,3-bis (2-methylindol-3-yl) phthalide, rhodamine B-anilinolactam, rhodamine B- (o-chloroanilino) lactam, rhodamine B- (p-nitroanilino) lactam, 3-diethylamino-5 -Methyl-7-dibenzylaminofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6-methoxyfluorane, 3-diethylamino-6-methylfluorane, 3-diethylamino-6 -Methyl-7-chloro-8-benzylfluorane, 3-diethylamino-6,7-dimethylfluorane, 3-diethylamino-6,8-dimethylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino -7-methoxyfluorane, 3-diethylamino-7- (N Acetyl-N-methyl) aminofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7-n-propoxyfluorane, 3-diethylamino-7-p-methylphenylfluorane, 3-diethylamino-7 , 8-benzofluorane, 3-diethylaminobenzo [a] fluorane, 3-diethylaminobenzo [c] fluorane, 3-dimethylamino-7-methoxyfluorane, 3-dimethylamino-6-methyl-7-chlorofluorane 3-dimethylamino-7-methylfluorane, 3-dimethylamino-7-chlorofluorane, 3- (N-ethyl-p-toluidino) -7-methylfluorane, 3- (N-ethyl-N- Isoamyl) amino-6-methyl-7-chlorofluorane, 3- (N-ethyl-N-isoamyl) Amino-7,8-benzofluorane, 3- (N-ethyl-N-isoamyl) amino-7-methylfluorane, 3- (N-ethyl-Nn-octyl) amino-6-methyl-7- Chlorofluorane, 3- (N-ethyl-Nn-octyl) amino-7,8-benzofluorane, 3- (N-ethyl-Nn-octyl) amino-7-methylfluorane, 3- (N-ethyl-Nn-octyl) amino-7-chlorofluorane, 3- (N-ethyl-N-4-methylphenyl) amino-7,8-benzofluorane, 3- (N-ethoxyethyl) -N-ethyl) amino-7,8-benzofluorane, 3- (N-ethoxyethyl-N-ethyl) amino-7-chlorofluorane, 3-n-dibutylamino-6-methyl-7-chlorofluor Oran, 3-n-Djibouti Amino-7,8-benzofluorane, 3-n-dibutylamino-7-chlorofluorane, 3-n-dibutylamino-7-methylfluorane, 3-diallylamino-7,8-benzofluorane, 3 -Diallylamino-7-chlorofluorane, 3-di-n-butylamino-6-methyl-7-bromofluorane, 3-cyclohexylamino-6-chlorofluorane, 3-pyrrolidylamino-7-methylfluor Oran, 3-ethylamino-7-methylfluorane, 3- (N-ethyl-N-isoamyl) amino-benzo [a] fluorane, 3-n-dibutylamino-6-methyl-7-bromofluorane, 3 , 6-bis (diethylaminofluorane) -γ- (4′-nitro) anilinolactam,

  Examples of green dye precursors include 3- (N-ethyl-Nn-hexyl) amino-7-anilinofluorane, 3- (N-ethyl-Np-tolyl) amino-7- (N -Phenyl-N-methyl) aminofluorane, 3- (N-ethyl-Nn-propyl) amino-7-dibenzylaminofluorane, 3- (N-ethyl-Nn-propyl) amino-6 -Chloro-7-dibenzylaminofluorane, 3- (N-ethyl-N-4-methylphenyl) amino-7- (N-methyl-N-phenyl) aminofluorane, 3- (N-ethyl-4) -Methylphenyl) amino-7-dibenzylaminofluorane, 3- (N-ethyl-4-methylphenyl) amino-6-methyl-7-dibenzylaminofluorane, 3- (N-ethyl-4-methyl) Phenyl) amino-6 Methyl-7- (N-methyl-N-benzyl) aminofluorane, 3- (N-methyl-Nn-hexyl) amino-7-anilinofluorane, 3- (N-propyl-Nn- Hexyl) amino-7-anilinofluorane, 3- (N-ethoxy-Nn-hexyl) amino-7-anilinofluorane, 3- (Nn-pentyl-N-allyl) amino-6 Methyl-7-anilinofluorane, 3- (Nn-pentyl-N-allyl) amino-7-anilinofluorane, 3-di-n-butylamino-6-chloro-7- (2-chloroanilino ) Fluorane, 3-di-n-butylamino-6-methyl-7- (2-chloroanilino) fluorane, 3-di-n-butylamino-6-methyl-7- (2-fluoroanilino) fluorane, 3 -N-Dibutylamino -7- (2-chloroanilino) fluorane, 3-di-n-butylamino-7- (2-chlorobenzylanilino) fluorane, 3,3-bis (4-diethylamino-2-ethoxyphenyl) -4-azaphthalide 3,6-bis (dimethylamino) fluorene-9-spiro-3 '-(6'-dimethylamino) phthalide, 3-diethylamino-6-methyl-7-benzylaminofluorane, 3-diethylamino-6-methyl -7-dibenzylaminofluorane, 3-diethylamino-6-methyl-7-n-octylaminofluorane, 3-diethylamino-6-methyl-7- (N-cyclohexyl-N-benzyl) aminofluorane, 3 -Diethylamino-6-methyl-7- (2-chloroanilino) fluorane, 3-diethylamino-6-methyl- 7- (2-trifluoromethylanilino) fluorane, 3-diethylamino-6-methyl-7- (3-trifluoromethylanilino) fluorane, 3-diethylamino-6-methyl-7- (2-ethoxyanilino) ) Fluorane, 3-diethylamino-6-methyl-7- (4-ethoxyanilino) fluorane, 3-diethylamino-6-chloro-7- (2-chloroanilino) fluorane, 3-diethylamino-6-chloro-7-di Benzylaminofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-diethylamino-6-ethylethoxy-7-anilinofluorane, 3-diethylamino-7-anilinofluorane, 3-diethylamino -7-methylanilinofluorane, 3-diethylamino-7-dibenzylamino Oran, 3-diethylamino-7-n-octylaminofluorane, 3-diethylamino-7-p-chloroanilinofluorane, 3-diethylamino-7-p-methylphenylanilinofluorane, 3-diethylamino-7- (N-cyclohexyl-N-benzyl) aminofluorane, 3-diethylamino-7- (2-chloroanilino) fluorane, 3-diethylamino-7- (3-trifluoromethylanilino) fluorane, 3-diethylamino-7- ( 2-trifluoromethylanilino) fluorane, 3-diethylamino-7- (2-ethoxyanilino) fluorane, 3-diethylamino-7- (4-ethoxyanilino) fluorane, 3-diethylamino-7- (2-chloro) Benzylanilino) fluorane, 3-dimethylamino-6- Loro-7-dibenzylaminofluorane, 3-dimethylamino-6-methyl-7-n-octylaminofluorane, 3-dimethylamino-7-dibenzylaminofluorane, 3-dimethylamino-7-n- Octylaminofluorane, 3-di-n-butylamino-7- (2-fluoroanilino) fluorane, 3-anilino-7-dibenzylaminofluorane, 3-anilino-6-methyl-7-dibenzylamino Fluorane, 3-pyrrolidino-7-dibenzylaminofluorane, 3-pyrrolidino-7- (4-cyclohexylanilino) fluorane, 3-dibenzylamino-6-methyl-7-dibenzylaminofluorane, 3, 7-bis (dibenzylamino) fluorane, 3-dibenzylamino-7- (2-chloroanilino) fluorane,

  Examples of blue dye precursors include 3- (1-ethyl-2-methylindol-3-yl) -3- (4-diethylaminophenyl) phthalide and 3- (1-ethyl-2-methylindole-3- Yl) -3- (2-methyl-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-aminophenyl)- 4-Azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-methylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindole) -3-yl) -3- (2-ethoxy-4-ethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-) The Tilaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl- 2-Methylindol-3-yl) -3- (2-ethoxy-4-di-n-propylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3 -(2-Ethoxy-4-di-n-butylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-di-n -Pentylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-di-n-hexylaminophenyl) -4-azaphthal 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-dihydroxyaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindole-3) -Yl) -3- (2-ethoxy-4-dichloroaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-dibromoamino) Phenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diallylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2) -Methylindol-3-yl) -3- (2-ethoxy-4-dihydroxyaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3 -(2-Ethoxy-4-dimethoxyaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethoxyaminophenyl) -4 -Azaphthalide, 3- (1-ethyl-2-methylindole-3-yl) -3- (2-ethoxy-4-dicyclohexylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindole- 3-yl) -3- (2-ethoxy-4-di-n-propoxyaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy -4-di-n-butoxyaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-di-n-hexyl) Oxyaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-di-methylcyclohexylaminophenyl) -4-azaphthalide, 3- ( 1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-di-methoxycyclohexylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) ) -3- (2-Ethoxy-4-pyrrolidylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (3-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2,3-diethoxy-4-diethylaminophenyl) 4-Azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-Chloro-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (3-chloro-4-diethylaminophenyl) -4- Azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-bromo-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindole-3- Yl) -3- (3-bromo-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethyl- 4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-n-propyl-4-diethylaminophenyl) -4-azaphthalide, 3- (1 -Ethyl-2-methylindol-3-yl) -3- (3-methyl-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- ( 2-nitro-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-allyl-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-hydroxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl- -Methylindol-3-yl) -3- (2-cyano-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-cyclohexylethoxy) -4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-methylethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1 -Ethyl-2-methylindol-3-yl) -3- (2-cyclohexylethyl-4-diethylaminophenyl) -4-azaphthalide, 3- (2-ethylindol-3-yl) -3- (2-ethoxy -4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-chloroindol-3-yl) -3- (2-eth Ci-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-bromoindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1 -Ethyl-2-ethylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-propylindol-3-yl) -3- ( 2-Ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methoxyindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-ethoxyindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1 -Ethyl-2-phenylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- ( 2-ethoxy-4-diethylaminophenyl) -7-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4,7-diazaphthalide, 3- (1-ethyl-4,5,6,7-tetrachloro-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1- Ethyl-4-nitro-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-4-methyl) Xyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-4-methylamino-2-methylindol-3-yl) -3- (2-Ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-4-methyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) ) -4-Azaphthalide, 3- (2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-chloro-2-methylindole-3- Yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-bromo-2-methylindol-3-yl) -3- ( -Ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-methyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- ( 1-methyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -7-azaphthalide, 3- (1-n-propyl-2-methylindol-3-yl)- 3- (2-Ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-n-butyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4 -Azaphthalide, 3- (1-n-butyl-2-indol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -7-azaphthalide 3- (1-n-pentyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-n-hexyl-2-methylindole) -3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-n-hexyl-2-methylindol-3-yl) -3- (2-ethoxy-4) -Diethylaminophenyl) -7-azaphthalide, 3- (1-n-octyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1- n-octyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -7-azaphthalide, 3- (1-n-octyl-2-methyl) Ndol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4,7-diazaphthalide, 3- (1-n-nonyl-2-methylindol-3-yl) -3- (2- Ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-methoxy-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1 -Ethoxy-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-phenyl-2-methylindol-3-yl) -3- ( 2-Ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-n-pentyl-2-methylindol-3-yl) -3- (2-ethoxy- -Diethylaminophenyl) -7-azaphthalide, 3- (1-n-heptyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -7-azaphthalide, 3- (1- n-nonyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -7-azaphthalide, 3,3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide 3- (4-Dimethylamino-2-methylphenyl) -3- (4-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (1-ethyl-2-methylindol-3-yl) -3 -(4-diethylamino-2-n-hexyloxyphenyl) -4-azaphthalide and the like. These can be used alone or in admixture of two or more.

  Some functional dye precursors have absorption in the near infrared region. When this dye precursor is used alone or in combination with other dye precursors for high-temperature color development, automatic reading with a near-infrared lamp that absorbs high-temperature color images in the near-infrared region is possible. Possible images can be obtained. When this dye precursor is used in the present invention, an image having an absorption only in the visible region, an image having an absorption in the near infrared region, and the like can be used in combination, and a recording material with high security can be obtained.

  As such a dye having absorption in the near infrared region, 3,3-bis [1- (4-methoxyphenyl) -1- (4-dimethylaminophenyl) ethylene-2-yl] -4,5 , 6,7-tetrachlorophthalide, 3,3-bis [1- (4-methoxyphenyl) -1- (4-pyrrolidinophenyl) ethylene-2-yl] -4,5,6,7-tetra Chlorophthalide, 3,3-bis [1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl] -4,5,6,7-tetrabromophthalide, 3- [1,1-bis (P-diethylaminophenyl) ethylene-2-yl] -6-dimethylaminophthalide, 3,6-bis (dimethylamino) fluorene-9-spiro-3 '-(6'-dimethylamino) phthalide, 3- [ p- (p-dimethylaminoanilino) Nilino] -6-methylfluorane, 3- [p- (p-dimethylaminoanilino) anilino] -6-methyl-7-chlorofluorane, 3- (pn-butylaminoanilino) -6 Methyl-7-chlorofluorane, 3- [p- (p-anilinoanilino) anilino] -6-methyl-7-chlorofluorane, 3- [p- (p-chloroanilino) anilino] -6-methyl-7- Chlorofluorane, 3- (Np-tolyl-N-ethylamino) -6,8,8-trimethyl-9-ethyl-8,9-dihydro- (3,2, e) pyridfluorane, 3-di ( n-butyl) amino-6,8,8-trimethyl-8,9-dihydro- (3,2, e) pyridfluorane, 3'-phenyl-7-N-diethylamino-2,2'-spirodi (2H-1 -Benzopyran), Scan (p- dimethylaminostyryl)-p-tri sulfonyl methane, 3,7-bis (dimethylamino) -10-benzoyl-phenothiazine, and the like. These electron donating dye precursors may be used alone or in combination of two or more as required.

  Next, as the electron-accepting developer in the present invention, compounds generally used for heat-sensitive recording materials can be used. Specific examples include the following, but the present invention is not limited thereto.

  4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-propoxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4'-allyloxy Diphenylsulfone, 4-hydroxy-4'-octyloxydiphenylsulfone, 4-hydroxy-4'-dodecyloxydiphenylsulfone, 4-hydroxy-4'-benzyloxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) Sulfone, 3,4-dihydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-benzenesulfonyloxydiphenylsulfone, 2,4-bis (phenylsulfonyl) phenol, p-phenylphenol, p-hydro Cyacetophenone, 1,1-bis (p-hydroxyphenyl) propane, 1,1-bis (p-hydroxyphenyl) pentane, 1,1-bis (p-hydroxyphenyl) hexane, 1,1-bis (p- Hydroxyphenyl) cyclohexane, 2,2-bis (p-hydroxyphenyl) propane, 2,2-bis (p-hydroxyphenyl) hexane, 1,1-bis (p-hydroxyphenyl) -2-ethylhexane, 2, 2-bis (3-chloro-4-hydroxyphenyl) propane, 1,1-bis (p-hydroxyphenyl) -1-phenylethane, 1,3-bis [2- (p-hydroxyphenyl) -2-propyl Benzene, 1,3-bis [2- (3,4-dihydroxyphenyl) -2-propyl] benzene, 1,4-bis [2- (p- Loxyphenyl) -2-propyl] benzene, 4,4'-dihydroxydiphenyl ether, 3,3'-dichloro-4,4'-dihydroxydiphenyl sulfide, methyl 2,2-bis (4-hydroxyphenyl) acetate, 2, 2-bis (4-hydroxyphenyl) butyl acetate, 4,4′-thiobis (2-tert-butyl-5-methylphenol), dimethyl 4-hydroxyphthalate, benzyl 4-hydroxybenzoate, 4-hydroxybenzoic acid Methyl, benzyl gallate, stearyl gallate, N, N'-diphenylthiourea, 4,4'-bis [3- (4-methylphenylsulfonyl) ureido] diphenylmethane, N- (4-methylphenylsulfonyl) -N '-Phenylurea, salicylanilide, 5-chlorosalicylanilide, salicy Phosphoric acid, 3,5-di-tert-butylsalicylic acid, 3,5-bis (α-methylbenzyl) salicylic acid, 4- [2 ′-(4-methoxyphenoxy) ethyloxy] salicylic acid, 3- (octyloxycarbonylamino) ) Salicylic acid or metal salts of these salicylic acid derivatives, N- (4-hydroxyphenyl) -p-toluenesulfonamide, N- (4-hydroxyphenyl) benzenesulfonamide, N- (4-hydroxyphenyl) -1-naphthalenesulfone Amide, N- (4-hydroxyphenyl) -2-naphthalenesulfonamide, N- (4-hydroxynaphthyl) -p-toluenesulfonamide, N- (4-hydroxynaphthyl) benzenesulfonamide, N- (4-hydroxy Naphthyl) -1-naphthalenesulfonamide, N- (4 Hydroxynaphthyl) -2-naphthalenesulfonamide, N- (3-hydroxyphenyl) -p-toluenesulfonamide, N- (3-hydroxyphenyl) benzenesulfonamide, N- (3-hydroxyphenyl) -1-naphthalenesulfone Amide, N- (3-hydroxyphenyl) -2-naphthalenesulfonamide, N- (4-methylphenylsulfonyl) -N ′-[3- (4-methylphenylsulfonyloxy) phenyl] urea, bis (4-tosyl) Aminocarboxyaminophenyl) methane, urea urethane compound, sulfonylurea compound and the like. These electron-accepting developers can be used alone or in combination of two or more as required.

  The content ratio of the dye precursor and the electron-accepting developer is appropriately determined depending on the type and the combination thereof. The total amount of the electron-accepting compound is 100 to 500 with respect to the total amount of the dye precursor. It is used by containing 1% by mass, preferably 150 to 350% by mass.

  In addition to the main components described above, known adhesives, hot melt compounds, preservability improvers, surfactants, and the like may be added to the heat-sensitive recording layer according to the present invention. Those having less influence on properties and thermal transfer acceptability of the ink ribbon are particularly preferable.

  Specific examples of the adhesive include starches, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, gelatin, casein, fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, Diacetone modified polyvinyl alcohol, silanol group modified polyvinyl alcohol, sulfonic acid group modified polyvinyl alcohol, phosphate group modified polyvinyl alcohol, butyral group modified polyvinyl alcohol, epoxy modified polyvinyl alcohol, chitosan, polyacrylic acid, polymethacrylic acid, polyacrylic ester , Polymethacrylate, polyacrylic acid soda, polyethylene terephthalate, polybutylene Phthalate, chlorinated polyether, allyl resin, furan resin, ketone resin, oxybenzoyl polyester, polyacetal, polyether ether ketone, polyether sulfone, polyimide, polyamide, polyamideimide, polyaminobismaleimide, polymethylpentene, polyphenylene oxide, polyphenylene Sulfide, polyphenylenesulfone, polysulfone, polyarylate, polyallylsulfone, polybutadiene, polycarbonate, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyurethane, phenol resin, urea resin, melamine resin, melamine formalin resin , Benzoguanamine resin, bismaleimide triazine resin, alkyd resin, amino resin, Poxy resin, unsaturated polyester resin, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer, methyl acrylate / butadiene copolymer, ethylene / vinyl acetate copolymer, acrylate amide / acrylate ester copolymer, Acrylic acid amide / acrylic acid ester / methacrylic acid terpolymer, styrene / maleic anhydride copolymer alkali salt, ethylene / maleic anhydride copolymer alkali salt or ammonium salt, and other various polyolefin resins These may be used alone or in combination of two or more.

  The hot-melt compound is used as a sensitizer for obtaining sufficient color development sensitivity. For example, stearic acid amide, N-hydroxymethyl stearic acid amide, N-stearyl stearic acid amide, ethylenebisstearic acid amide, N-stearyl Urea, benzyl-2-naphthyl ether, m-terphenyl, 4-benzylbiphenyl, 1,2-bis (3-methylphenoxy) ethane, 1,2-diphenoxyethane, 2,2'-bis (4-methoxy) Phenoxy) diethyl ether, α, α′-diphenoxyxylene, bis (4-methoxyphenyl) ether, diphenyl adipate, dibenzyl oxalate, bis (4-chlorobenzyl) oxalate, dimethyl terephthalate, dibenzyl terephthalate, Benzylparaben, phenylbenzenesulfonate Well-known hot-melt compounds such as esters, 4,4'-diallyloxydiphenylsulfone, diphenylsulfone, 4-acetylacetophenone, acetoacetic anilides, fatty acid anilides and salicylanilide are exemplified. These compounds can be used alone or in combination of two or more.

  The storability improver is used to enhance the storability of the color image portion. For example, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-ethylenebis (4-methyl) is used. -6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4,6-di-tert-butylphenol), 2,2'-ethylidene Bis (4,6-di-tert-butylphenol), 2,2'-ethylidenebis (4-ethyl-6-tert-butylphenol), 2,2 '-(2,2-propylidene) bis (4,6- Di-tert-butylphenol), 2,2'-methylenebis (4-methoxy-6-tert-butylphenol), 2,2'-methylenebis (6-t rt-butylphenol), 4,4'-thiobis (3-methyl-6-tert-butylphenol), 4,4'-thiobis (2-methyl-6-tert-butylphenol), 4,4'-thiobis (5- Methyl-6-tert-butylphenol), 4,4'-thiobis (2-chloro-6-tert-butylphenol), 4,4'-thiobis (2-methoxy-6-tert-butylphenol), 4,4'- Thiobis (2-ethyl-6-tert-butylphenol), 4,4'-butylidenebis (6-tert-butyl-m-cresol), 1- [α-methyl-α- (4'-hydroxyphenyl) ethyl]- 4- [α ', α'-bis (4 "-hydroxyphenyl) ethyl] benzene, 1,1,3-tris (2-methyl-4-hydroxy-5 -Cyclohexylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 4,4'-thiobis (3-methylphenol), 4,4'-dihydroxy -3,3 ', 5,5'-tetrabromodiphenylsulfone, 4,4'-dihydroxy-3,3', 5,5'-tetramethyldiphenylsulfone, 2,2-bis (4-hydroxy-3, Hindered phenol compounds such as 5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, N, N'-bis (2-naphthyl) -1,4-phenylenediamine, 2,2'-methylenebis (4,6-di-tert-butylphenyl) Phosphate sodium, diphenylsulfone crosslinked type compound, may be added to an isocyanate compound.

  In the present invention, various pigments can be used in accordance with the purpose of improving the whiteness and the like within a range that does not impair the desired effect on the above-described problems. For example, diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, titanium dioxide, zinc oxide, silicon oxide, amorphous silica, amorphous calcium silicate, colloidal silica, Well-known pigments such as white inorganic pigments such as colloidal alumina, calcium sulfate, barium sulfate, zinc sulfide, zinc carbonate, satin white, aluminum silicate, calcium silicate, magnesium silicate, alumina, lithopone, zeolite, and hydrohalloysite can be mentioned.

  In addition, waxes such as higher fatty acid metal salts such as zinc stearate and calcium stearate and paraffin, oxidized paraffin, polyethylene, oxidized polyethylene, and caster wax, which are used to improve sticking resistance, are water resistant. In addition, various hardeners and cross-linking agents may be incorporated, such as a dispersing agent such as sodium dioctylsulfosuccinate, a surfactant, a fluorescent dye, a coloring dye, and a bluing agent.

  In addition, in order to improve light resistance, an antioxidant and an ultraviolet absorber can be contained. Examples of antioxidants include, but are not limited to, hindered amine antioxidants, hindered phenol antioxidants, sulfide antioxidants, and the like. Examples of UV absorbers include organic compounds such as benzotriazole UV absorbers, salicylic acid UV absorbers, and benzophenone UV absorbers, and inorganic substances such as zinc oxide, titanium oxide, and cerium oxide. There is no limitation.

  In the present invention, a protective layer is provided on the heat-sensitive recording layer for the purpose of improving the sticking resistance, preventing scratches, improving the water resistance, and improving the plasticizer resistance and chemical resistance of the heat-sensitive color image. The protective layer contains various adhesives, inorganic pigments, various curing agents, various crosslinking agents, ultraviolet absorbers, and the like, and a single layer or two or more layers can be laminated. Further, printing with UV ink or the like may be performed on the surface of the heat-sensitive recording layer or the protective layer.

The dry weight of the heat-sensitive recording layer, 3 to 15 g / m ² is preferred. If the amount is less than 3 g / m ² , the effect of improving thermal transfer acceptance is small, and the thermal color development sensitivity is also low. If the amount is more than 15 g / m ^2, various performance improvements of the thermal recording layer reach saturation, and the thermal recording layer is coated. Production efficiency at the time decreases. On the other hand, the dry weight of the protective layer, 0.5 to 5 g / m ² is preferred. If the amount is less than 0.5 g / m ² , various performances of the protective layer are not exhibited, and if it is more than 5 g / m ² , the loss of thermal energy reaching the thermal recording layer from the thermal head increases, and thermal transfer acceptability and thermal color development. Degradation of characteristics is caused.

  In the present invention, the support on which the heat-sensitive recording layer is provided may be any of transparent, translucent, and opaque. Paper, various nonwoven fabrics, woven fabric, synthetic resin film, synthetic resin laminated paper, synthetic paper, metal foil A ceramic sheet, a glass plate, or a composite sheet obtained by combining these can be arbitrarily used depending on the purpose. Further, an intermediate layer may be provided between the heat-sensitive recording layer and the support in order to improve smoothness, heat insulation and the like. The intermediate layer can contain various adhesives, organic pigments, inorganic pigments, hollow particles, and the like.

  In the present invention, a backcoat layer may be provided on the surface opposite to the surface on which the heat-sensitive recording layer is provided for the purpose of preventing curling or preventing charging, and may further be subjected to adhesive processing. In addition, a layer including a material capable of recording information electrically, magnetically, or optically, an ink jet recording layer, or the like may be provided on the surface on which the thermosensitive recording layer is provided or on the opposite surface. In addition, in order to perform printing with a laser beam, a photothermal conversion material can be contained in an arbitrary layer and support in the thermosensitive recording material.

  The formation method of each layer in the present invention is not particularly limited, and can be formed by using a well-known technique. For example, a coating apparatus such as an air knife coater, various blade coaters, various bar coaters, and various curtain coaters. In addition, various printing methods such as a planographic plate, a relief plate, an intaglio plate, a flexo, a gravure, and a screen can be used. Furthermore, in order to improve the surface smoothness, various known techniques in the production of heat-sensitive recording materials can be used, such as the use of machines such as a machine calendar, super calendar, gloss calendar, and brushing.

Example 1
In the following manner, a heat-sensitive recording material used in Example 1 was produced and evaluated for characteristics. “Part” means “part by mass”.

(1) Preparation of thermosensitive recording layer coating solution The dispersions of (A) to (C) prepared as follows were each used for volume average particle diameter of 0.8 μm using Dynomill (manufactured by Shinmaru Enterprises). Wet ground until.
(A) Black coloring dye precursor dispersion 10% by weight polyvinyl alcohol aqueous solution (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gocelan L3266) 58.0 parts 3-di-n-butylamino-6-methyl-7-ani Linofluorane 72.0 parts Water 110.0 parts (B) Electron-accepting developer dispersion 10% by weight polyvinyl alcohol aqueous solution (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gocelan L3266) 86.0 parts N- ( 4-methylphenylsulfonyl) -N '-[3- (4-methylphenylsulfonyloxy) phenyl] urea 108.0 parts water 166.0 parts (C) hot melt compound dispersion 10% by weight polyvinyl alcohol aqueous solution (Nippon Synthesis) 86.0 parts 1,2-bis (3-methylphenoxy) ethane 108.0 parts water 166.0 parts, manufactured by Chemical Industry Co., Ltd., Gohselan L3266

A thermosensitive recording layer coating solution comprising the following components was prepared.
(A) Dispersion 240.0 parts (B) Dispersion 360.0 parts (C) Dispersion 360.0 parts Hollow resin particles Ropaque HP-91 (dispersion concentration 27.5 mass%) 270.0 parts 40 mass% Zinc stearate aqueous dispersion 90.0 parts 10% by weight polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., NM-11) aqueous solution
720.0 parts water 560.0 parts

(2) Preparation of intermediate layer coating solution An intermediate layer coating solution comprising the following components was prepared.
10 mass% sodium hexametaphosphate aqueous solution 10.0 parts calcined kaolin (manufactured by Engelhard, Ansilex) 100.0 parts 25 mass% oxidized starch aqueous solution 24.0 parts 48 mass% SBR latex dispersion 25.0 parts water 105. 0 copies

(3) Preparation of protective layer coating solution A protective layer coating solution comprising the following components was prepared.
Fine kaolin (manufactured by Huber, HG-90) 5.0 parts 40 mass% zinc stearate aqueous dispersion 1.0 part 10 mass% diacetone-modified polyvinyl alcohol aqueous solution (manufactured by Nihon Acetate / Poval) DM- 17) 100.0 parts 8% by weight adipic acid dihydrazide aqueous solution 12.5 parts water 25.0 parts

(4) Formation of intermediate layer The intermediate layer coating solution prepared in (2) was coated on a high-quality paper of 150 g / m ^{2 with} a blade coater and dried so that the solid content was 10 g / m ^2. A layer was formed.

(5) Formation of heat-sensitive recording layer The heat-sensitive recording layer coating solution prepared in (1) is applied and dried on the intermediate layer with an air knife coater so that the solid content is 8 g / m ² and heat-sensitive. A recording layer was formed.

(5) Formation of protective layer The protective layer coating solution prepared in (3) was applied and dried on the heat-sensitive recording layer with an air knife coater so that the solid content was 2 g / m ^2. The coated paper was calendered and finished so as to have a Beck smoothness of 900 to 1100 seconds to obtain a heat-sensitive recording material of Example 1.

  The produced thermal recording material was subjected to the following evaluation.

Evaluation 1 [Thermal transfer acceptability]
Using the printing test machine (TH-PMD) manufactured by Okura Electric Co., Ltd. with the ink surface of the resin-type thermal transfer ink ribbon (General Technology Co., Ltd. SD1100, black) overlaid on the thermal recording surface of the thermal recording material. Then, thermal transfer printing was performed with an applied energy of 0.15 mJ / dot. The printing density at that time was measured with a reflection densitometer RD-19 manufactured by Gretag Macbeth. In addition, the thermal transfer printed matter was evaluated as “Good” when there was no printing defect, “Slightly generated but practical” as Δ, and “Severely generated” as “Poor”. The evaluation results are shown in Table 1.

Evaluation 2 [Sticking resistance]
Thermal printing was performed using a handy terminal printer (manufactured by Canon Inc., HT-180). Evaluation was made with ◯ indicating that no sticking occurred and printing was good, Δ being slightly generated but practical, and X indicating severe occurrence. The evaluation results are shown in Table 1.

Evaluation 3 [Single color thermal sensitivity]
Using a printing test machine (TH-PMD) manufactured by Okura Electric Co., Ltd., black printing was performed with an applied energy of 0.25 mJ / dot. The printing density at that time was measured with a Macbeth reflection densitometer RD-19 type. The evaluation results are shown in Table 1.

Example 2
A thermosensitive recording material was produced in the same manner as in Example 1 except that Ropaque HP-91 was changed as follows in the composition of the thermosensitive recording layer coating solution, and evaluations 1 to 3 were performed. The evaluation results are shown in Table 1.
Hollow resin particles Ropaque OP-84J (dispersion concentration: 37.5% by mass) 197.0 parts

Example 3
A thermosensitive recording material was produced in the same manner as in Example 1 except that Ropaque HP-91 was changed as follows in the composition of the thermosensitive recording layer coating solution, and evaluations 1 to 3 were performed. The evaluation results are shown in Table 1.
Vertical resin particles MH8055 (dispersion concentration: 30.0% by mass) 247.0 parts

Example 4
A thermosensitive recording material was produced in the same manner as in Example 1 except that Ropaque HP-91 was changed as follows in the composition of the thermosensitive recording layer coating solution, and evaluations 1 to 3 were performed. The evaluation results are shown in Table 1.
Hollow resin particles having through-holes Grosdale 2001TX (dispersion concentration 20.0% by mass)
370.0 parts

Example 5
The black color developing dye precursor dispersion (liquid (A)) is applied to the black color developing dye precursor coating liquid (liquid (D)) for high temperature coloration as described below, and a new red color developing dye for low temperature color development. A precursor dispersion (liquid (E)) was prepared.

(D) Black coloring dye precursor coating solution for high-temperature color development 240 parts of Liquid A was transferred to a polymerization vessel, 16 parts of methyl methacrylate and 4 parts of ethylene glycol dimethacrylate were added, and the temperature was raised to 70 ° C. with stirring. To this, 24 parts of a 1% by mass potassium persulfate aqueous solution as a polymerization initiator was added and reacted for 6 hours while stirring was continued. Next, this was cooled to room temperature, and a dispersion liquid D of dye precursor particles for high-temperature color development provided with a color development control layer on the surface was obtained.

(E) 10 mass% polyvinyl alcohol aqueous solution (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gocelan L3266) 42.5 parts 3-diethylamino-7-chlorofluorane 42.5 30.0 parts water

A multicolor-colored heat-sensitive recording layer coating solution comprising the following components was prepared, and the multicolor-colored heat-sensitive recording was performed in the same manner as in Example 1 except that the coating amount was 9 g / m ^2. The material was made.
(B) Liquid 360.0 parts (C) Liquid 360.0 parts (D) Liquid 284.0 parts (E) Liquid 115.0 parts Hollow resin particles Ropaque HP-91 (dispersion concentration 27.5 mass%) 270. 0 parts 40% by weight zinc stearate aqueous dispersion 90.0 parts 10% by weight polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., NM-11) aqueous solution
720.0 parts water 560.0 parts

  The produced multicolor-colored heat-sensitive recording material was subjected to Evaluations 1 and 2 and Evaluations 4 and 5 below. The evaluation results are shown in Table 1.

Evaluation 4 [Thermal Sensitivity of Multicolor Coloring]
Using a printing test machine (TH-PMD) manufactured by Okura Electric Co., Ltd., low-colored red printing with an applied energy of 0.25 mJ / dot and high-temperature colored black printing with an applied energy of 0.50 mJ / dot It was. The printing density at that time was measured with a Macbeth reflection densitometer RD-19 type. The evaluation results are shown in Table 1.

Evaluation 5 [Color separation of multicolor development]
Samples printed in two colors in Evaluation 4 were visually observed for color separation between red and black color development. The red color development was not turbid and the color separation was clear. Those with unclear color separation were evaluated as x. The evaluation results are shown in Table 1.

Example 6
A multicolor-colored heat-sensitive recording material was prepared in the same manner as in Example 5 except that Ropaque HP-91 was changed as follows in the composition of the heat-sensitive recording layer coating solution, and evaluations 1, 2, 4, 5 Carried out. The evaluation results are shown in Table 1.
Vertical resin particles MH8055 (dispersion concentration: 30.0% by mass) 247.0 parts

Example 7
A multicolor-colored heat-sensitive recording material was prepared in the same manner as in Example 5 except that Ropaque HP-91 was changed as follows in the composition of the heat-sensitive recording layer coating solution, and evaluations 1, 2, 4, 5 Carried out. The evaluation results are shown in Table 1.
Resin particles having through-holes Grosdale 2001TX (dispersion concentration 20.0% by mass)
370.0 parts

Comparative Example 1
A heat-sensitive recording material was produced in the same manner as in Example 1 except that Ropaque HP-91 was excluded from the composition of the heat-sensitive recording layer coating solution, and evaluations 1 to 3 were performed. The evaluation results are shown in Table 1.

Comparative Example 2
A thermosensitive recording material was produced in the same manner as in Example 1 except that Ropaque HP-91 was changed as follows in the composition of the thermosensitive recording layer coating solution, and evaluations 1 to 3 were performed. The evaluation results are shown in Table 1.
Dense resin particles Grosdale 202-S (dispersion concentration: 35.0% by mass) 210.0 parts

Comparative Example 3
In the composition of the heat-sensitive recording layer coating solution, except for Ropaque HP-91, the intermediate layer coating solution was changed as follows, and except that Ropaque HP-91 was contained in the intermediate layer, the same as in Example 1. A heat-sensitive recording material was prepared and evaluated 1-3. The evaluation results are shown in Table 1.
8.6 parts calcined kaolin (manufactured by Engelhard, Ansilex) 86.0 parts Ropaque HP-91 (dispersion concentration 27.5 mass%) 52.0 parts 25 mass% oxidized starch aqueous solution 24 0.0 part 48% by weight SBR latex dispersion 25.0 parts water 105.0 parts

Comparative Example 4
In the composition of the thermal recording layer coating solution, except for Ropeke HP-91, the protective layer coating solution is changed as follows, and Ropeke HP-91 is contained in the protective layer, and the solid content of the protective layer coating solution is applied. A thermosensitive recording material was prepared in the same manner as in Example 1 except that the amount was 4 g / m ^2, and evaluations 1 to 3 were performed. The evaluation results are shown in Table 1.
Ropaque HP-91 (dispersion concentration 27.5% by mass) 18.0 parts 40% by weight zinc stearate aqueous dispersion 1.0 part 10% by weight diacetone-modified polyvinyl alcohol aqueous solution DM-17) 100.0 parts 8 wt% adipic acid dihydrazide aqueous solution 12.5 parts water 25.0 parts

Comparative Example 5
In the composition of the heat-sensitive recording layer coating liquid, except for Ropaque HP-91, the black dye precursor dispersion liquid ((D) liquid) for high-temperature color development was coated with the black dye precursor dispersion liquid ((A) liquid) 240. A heat-sensitive recording material was produced in the same manner as in Example 5 except that the content was changed to 0.0 part, and evaluations 1, 2, 4, and 5 were performed. The evaluation results are shown in Table 1.

  As is clear from the results in Table 1, Examples 1 to 4 are excellent in all evaluation items of thermal transfer acceptability, anti-sticking property, and thermal color development sensitivity, and Examples 5 to 7 are more excellent in multicolor color development. It was excellent. On the other hand, Comparative Examples 1 to 4 in which none of the heat-sensitive recording layer contains hollow resin particles, bowl-shaped resin particles, or hollow resin particles having through-holes have low thermal transfer acceptability or low sticking resistance. . Furthermore, in Comparative Example 5 in which the black dye precursor did not have a color adjusting layer, multicolor coloring was not obtained.

Claims (2)

  A heat-sensitive recording material comprising, on a support, a heat-sensitive recording layer and an electron-accepting compound that reacts with an electron-donating ordinary colorless or light-colored dye precursor upon heating to develop a color of the dye precursor, and a protective layer. The heat-sensitive recording material according to claim 1, wherein the heat-sensitive recording layer contains at least one of hollow resin particles, bowl-shaped resin particles, and hollow resin particles having through holes.   2. The heat-sensitive recording material according to claim 1, wherein the dye precursor contains two or more kinds that develop colors different from each other, and at least one kind is present in the form of particles having a color adjusting layer on the surface.