JP4584030B2 - Two-color thermal coloring material - Google Patents

Description

  The present invention relates to a two-color thermosensitive coloring material, and more specifically, black-red two-color thermosensitive coloring material or blue-red two-coloring that develops black color or blue color by heating to a relatively low temperature and red color by heating to a relatively high temperature. The present invention relates to a color thermal coloring material.

  A heat-sensitive recording material is generally a thermal head (thermal head) in which a heat-sensitive recording layer mainly comprising a colorless or light-colored electron-donating dye precursor and an electron-accepting developer is provided on a support. By heating with a thermal pen, laser light or the like, the dye precursor and the developer react instantaneously to obtain a color image, and Japanese Patent Publication No. 43-4160 and Japanese Patent Publication No. 45-14039, etc. Is disclosed.

  Such a heat-sensitive recording material has advantages such as that recording can be obtained with a relatively simple device, easy maintenance, no noise generation, etc., measurement recorder, facsimile, printer, computer terminal, It is used in a wide range of fields, such as labels and ticket vending machines.

  On the other hand, in many uses of heat-sensitive recording materials, a multi-color coloring heat-sensitive recording material capable of developing colors in two or more colors depending on the heating temperature is desired. As a method for realizing such a multicolor coloring thermal recording material, the coloring temperature is adjusted by changing the melting point of the dye precursor, and only the dye precursor having a low coloring temperature develops color at low temperature heating, and the coloring temperature at high temperature. Low dye precursors and dye precursors with higher color development temperatures to develop colors at the same time, and to develop colors different from those at low temperature heating, the dye precursors are contained in separate layers stacked for each type, and more A method is known in which a dye precursor contained in a surface layer near the heating source develops color at a lower heating temperature, and a dye precursor contained in a layer separated from the surface develops color at a higher heating temperature. ing. In the former method of adjusting the color development temperature by changing the melting point of the dye precursor, the materials that can be used are limited, and there is a problem that the balance with other properties cannot be obtained sufficiently. In order to make it contain in the same layer, the device which prevents the dye precursor from which a kind differs interacts mutually and develops a color is needed. In addition, the latter method in which the dye precursor is contained in separate layers laminated for each type has a problem that the layer structure of the multicolor heat-sensitive recording material becomes complicated and the productivity is poor.

  In order to solve these problems, a method has been proposed in which a dye precursor is encapsulated in a microcapsule and the microcapsule wall has a role as a color adjustment layer, thereby adjusting color development characteristics such as a color development temperature. For example, a method is disclosed in which a plurality of dye precursors and color developers having different color tones are contained in the same layer, and at least one of the dye precursors is encapsulated in a microcapsule (see, for example, Patent Document 1). ). According to this method, it is possible to increase the temperature at which the dye precursor encapsulated in the microcapsule reacts with the developer to develop color, and the dye precursor encapsulated in the microcapsule and the dye precursor not encapsulated. Since they do not interact with each other, two or more colors can be obtained with a single heat-sensitive recording layer.

  Various microencapsulation methods can be applied as a method for forming a color adjustment layer on the surface of the dye precursor, but the capsule wall of the microcapsule must be thermoplastic to adjust the color development characteristics such as the color development temperature. is there. As a method for coating the coloring component with a thermoplastic microcapsule wall, an interfacial polymerization method, a coacervation method, a spray drying method, a submerged curing coating method, a melt dispersion cooling method and the like are known. When encapsulating the dye precursor in a microcapsule, these compounds are usually solids. Therefore, when using the interfacial polymerization method, the dye precursor is dissolved in a solvent, the capsule wall raw material is added, and this is added to water. After emulsification in a medium such as the above, there is a method of evaporating the solvent in which the coloring component is dissolved and polymerizing the capsule membrane, but there is a disadvantage that the process becomes complicated and the productivity is lowered. In addition, when the coacervation method is used, the production conditions of the microcapsules are extremely limited, and the characteristics of the generated capsule wall are also limited. When the spray drying method is used, the capsule membrane is not uniform, and there are also disadvantages that the particle size of the capsule tends to be large. When the submerged curing coating method is used, there is a drawback that the particle size of the capsule tends to be large. When the melt dispersion cooling method is used, since the melting point of the capsule membrane is limited to a relatively low melting point, there is a drawback that the characteristics of the capsule wall thus produced are also limited. As described above, when a conventionally known microencapsulation method is used, it is not possible to encapsulate the coloring component in the microcapsule with good productivity and to freely adjust the characteristics of the capsule wall of the microcapsule.

  In addition, a method has been proposed in which a color precursor is adjusted as a composite particle of polyurea or polyurethane with a dye precursor, and the composite particle is contained in the thermal recording material to obtain a multicolor thermal recording material (for example, a patent). Reference 2). According to this method, it is stated that there is little decrease in sensitivity compared to the method using microcapsules, and color development due to pressure or friction is difficult to occur. However, in this method, in order to completely coat the electron donating dye precursor, a large amount of polyurea or polyurethane is contained, and sufficient sensitivity cannot be obtained. In addition, there is a drawback that the adjustment of color development characteristics is limited to some extent.

  As described above, the polychromatic thermosensitive recording material obtained by the conventional method employs a so-called additive type multi-color development, so that light color development is performed for low temperature color development and then deep color development is performed for high temperature color development. There was a restriction that it had to be.

Furthermore, some conventional methods necessitate a complicated process such as lamination or microencapsulation in order to isolate a plurality of dye precursors having different color tone from each other.
JP-A-8-282115 Japanese Patent Laid-Open No. 9-142525

  An object of the present invention is to provide a two-color thermosensitive coloring material capable of two-color color development with a simple configuration, and capable of vivid black-red color development or blue-red color development unlike an additive type.

As a result of earnest research on such problems, the inventors have invented the two-color thermosensitive coloring material of the present invention that can solve the problems. That is, the present invention is usually a colorless or pale colored, as an electron donating compound represented by the electron-donating compound represented by the following general formula (1) or the following general formula (2), 3-di -n- butyl Amino-6-methyl-7-anilino-fluorane, 3-diethylamino-6-methyl-7-anilino-fluorane, 4-anilino-8-di-n-butylamino-benzo [a] -fluorane and 4-anilino- A compound selected from 8-diethylamino-benzo [a] -fluorane , an electron-accepting developer that develops the dye precursor by heating to the first coloring temperature range, and a temperature higher than the first coloring temperature range. reacting with an amino group having R ₃ or R ₇ of the compound by heating, by forming a -CONH- bond, as an acylating agent allowed to discolor color tone of the compound, diphenyl Tan-4,4′-diisocyanate, 4,4 ′, 4 ″ -triisocyanate triphenylamine, 4,4 ′, 4 ″ -triisocyanate-2,5-dimethoxytriphenylamine and the following general formula It has been achieved by a two-color thermosensitive coloring material characterized by containing a compound selected from carboxylic acid hydrazide derivatives represented by (3).

In Formula 1, R ₁ and R ₂ each represent a hydrogen atom, an alkyl group, an alkenyl group, an alicyclic group, an aralkyl group, an aryl group, or a heterocyclic residue, and R ₁ and R ₂ can be directly or via a linking group. To form a ring structure. R ₃ represents an aryl group. R ₄ represents a hydrogen atom or an alkyl group.

In Formula 2, R ₅ and R ₆ each represent a hydrogen atom, an alkyl group, an alkenyl group, an alicyclic group, an aralkyl group, an aryl group, or a heterocyclic residue, and R ₅ and R ₆ may be directly or via a linking group. To form a ring structure. R ₇ represents an aryl group, and the substitution position of —NHR ₇ is the 2-position or the 4-position.

In Formula 3, R ₈ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or an aryl group.

An electron-donating compound represented by the general formula (1) or the general formula (2), which is usually colorless or pale, and an electron-accepting developer that causes the compound to develop color by heating to the first color development temperature range Acylation which changes the color tone of the compound by reacting with the amino group having R ₃ or R ₇ of the compound by heating from the first color developing temperature range to a higher temperature range to form a —CONH— bond. By containing an agent, it is possible to obtain a two-color thermosensitive color-developing material that gives a black-red or blue-red two-color image.

The two-color thermosensitive coloring material of the present invention will be described more specifically.
The two-color thermosensitive coloring material of the present invention is usually a colorless or light-colored electron-donating compound represented by the general formula (1) or an electron-donating dye precursor represented by the general formula (2), An electron-accepting developer for coloring the dye precursor by heating to one color development temperature range; and an amino group having R ₃ or R ₇ of the dye precursor by heating to a temperature higher than the first color development temperature range It is a two-color thermosensitive coloring material containing an acylating agent that changes the color tone of the dye precursor by reacting with OH to form a —CONH— bond.

In the compound represented by the general formula (1) according to the present invention, R ₁ and R ₂ each represent a hydrogen atom, an alkyl group, an alkenyl group, an alicyclic group, an aralkyl group, an aryl group, and a heterocyclic residue, R ₁ and R ₂ may be the same or different. R ₁ and R ₂ may be bonded directly or via a linking group to form a cyclic structure. Specific examples of R ₁ and R ₂ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isoamyl group, a 2-ethylhexyl group, and an n-octyl group as the alkyl group. Examples of the alkenyl group include a vinyl group and an allyl group. Examples of the alicyclic group include a cyclopentadienyl group, a cyclohexyl group, and a cyclohexenyl group. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. A benzyl group, 1-naphthylmethyl group and the like as an aralkyl group, and examples of a heterocyclic residue include a furyl group, a tetrahydrofuryl group, a thienyl group, a pyridyl group, a pyrimidyl group, a pyrazyl group, a pyrazolyl group, and a pyrazolydyl group. Group, piperidyl group, indolyl group, isoindolyl group, morpholyl group and the like.

In addition, the alkyl group, alkenyl group, alicyclic group, aralkyl group, aryl group, and heterocyclic residue in R ₁ and R ₂ may have a substituent such as a halogen atom, an alkyl group, or an alkoxy group. . Specific examples of the substituent include fluorine, chlorine, bromine and iodine as the halogen atom, and methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 2-ethylhexyl group as the alkyl group, n-octyl group and the like are mentioned. Examples of the alkoxy group include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group and the like, and other examples include benzyl group, furyl group, tetrahydrofuryl group and the like. It is done.

R ₃ represents an aryl group, and specific examples thereof include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. R ₃ may have a substituent such as a halogen atom or an alkoxy group. Specific examples of the substituent include fluorine, chlorine, bromine and iodine as the halogen atom, and examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group and an n-butoxy group. R ₄ represents a substituted or unsubstituted alkyl group or a hydrogen atom. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and a 2-ethylhexyl group. , N-octyl group and the like. The alkyl group for R ₄ is a halogen atom may have a substituent such as alkoxy groups, specific examples thereof, examples of the halogen atom fluorine, chlorine, bromine, iodine, and examples of the alkoxy group methoxy group , An ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and the like. The compound represented by the general formula (1) according to the present invention may be used alone or in combination of two or more.

In the compound represented by the general formula (2) according to the present invention, R ₅ and R ₆ are each a hydrogen atom, an alkyl group, an alkenyl group, an alicyclic group, an aralkyl group, an aryl group, or a heterocyclic residue. R ₅ and R ₆ may be the same or different. R ₅ and R ₆ may be bonded directly or via a linking group to form a cyclic structure. As specific examples of R ₅ and R ₆ , examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isoamyl group, 2-ethylhexyl group, and n-octyl group. Examples of the alkenyl group include a vinyl group and an allyl group. Examples of the alicyclic group include a cyclopentadienyl group, a cyclohexyl group, and a cyclohexenyl group. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. A benzyl group, 1-naphthylmethyl group and the like as an aralkyl group, and examples of a heterocyclic residue include a furyl group, a tetrahydrofuryl group, a thienyl group, a pyridyl group, a pyrimidyl group, a pyrazyl group, a pyrazolyl group, and a pyrazolidyl group. Group, piperidyl group, indolyl group, isoindolyl group, morpholyl group and the like.

In addition, the alkyl group, alkenyl group, alicyclic group, aralkyl group, aryl group, and heterocyclic residue in R ₅ and R ₆ may have a substituent such as a halogen atom, an alkyl group, or an alkoxy group. . Specific examples of the substituent include fluorine, chlorine, bromine and iodine as the halogen atom, and methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 2-ethylhexyl group as the alkyl group, n-octyl group and the like are mentioned. Examples of the alkoxy group include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group and the like, and other examples include benzyl group, furyl group, tetrahydrofuryl group and the like. It is done.

R ₇ represents an aryl group, and the substitution position of —NHR ₇ is the 2-position or the 4-position. Specific examples of R ₇ include phenyl group, tolyl group, xylyl group, and naphthyl group. R ₇ may have a substituent such as a halogen atom or an alkoxy group. Specific examples of the substituent include fluorine, chlorine, bromine and iodine as the halogen atom, and examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, and an n-butoxy group. In addition, a phenyl group, a furyl group, a tetrahydrofuryl group, etc. are mentioned. The compound represented by the general formula (2) according to the present invention may be used alone or in combination of two or more.

  In addition, as the electron-accepting developer according to the present invention, a developer used in a conventionally known heat-sensitive recording material can be used. That is, as the developer according to the present invention, a phenol compound, an aromatic carboxylic acid derivative, a salicylic acid derivative, or a polyvalent metal salt such as a zinc salt thereof, an N, N′-diarylthiourea derivative, an arylsulfonylurea derivative, A urethane compound, an isocyanate compound, etc. are mentioned.

  Specific examples of the developer according to the present invention include 4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4'- Benzyloxydiphenylsulfone, 4-hydroxy-4'-propoxydiphenylsulfone, 4-hydroxy-4'-allyloxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4'-methyldiphenyl Sulfone, 3,4-dihydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-benzenesulfonyloxydiphenylsulfone, 2,4-bis (phenylsulfonyl) phenol, 2,4-bis (phenylsulfonyl) -5 -Methylphenol, p- Phenylphenol, p-hydroxyacetophenone, 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- Ethyl hexane, 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] benze 1,4-bis [2- (p-hydroxyphenyl) -2-propyl] benzene, 4,4'-hydroxydiphenyl ether, 3,3'-dichloro-4,4'-hydroxydiphenyl sulfide, 2,2- Methyl bis (4-hydroxyphenyl) acetate, butyl 2,2-bis (4-hydroxyphenyl) acetate, 4,4′-thiobis (2-tert-butyl-5-methylphenol), dimethyl 4-hydroxyphthalate, Benzyl gallate, stearyl gallate, N, N'-diphenylthiourea, 4,4'-bis [3- (4-methylphenylsulfonyl) ureido] diphenylmethane, N- (4-methylphenylsulfonyl) -N'- Phenylurea, N- (4-methylphenylsulfonyl) -N ′-[3- (4-methylphenylsulfonyloxy) fe Urea, urea, salicylanilide, 5-chlorosalicylanilide, salicylic acid, 3,5-di-tert-butylsalicylic acid, 3,5-di-α-methylbenzylsalicylic acid, 4- (n-octyloxycarbonylamino) salicylic acid, 4- [2 '-(4-methoxyphenoxy) ethyloxy] salicylic acid or a metal salt thereof may be used.

  If the amount of the developer according to the present invention is too small, the dye precursor cannot be sufficiently developed. Conversely, if the amount is too large, an excessive amount of developer can be developed even if the dye precursor can be sufficiently developed. Since the color density is not improved because the dye precursor is originally diluted with the agent, the amount of the developer with respect to the dye precursor is preferably in the range of 5 to 500% by mass, and in the range of 20 to 400% by mass. Is preferred. The developer according to the present invention may be used alone or in combination of two or more.

An acylating agent is a reagent for introducing an acyl group into an organic compound, and carboxylic acid halides (acyl halides), carboxylic acid anhydrides, isocyanate compounds, imidazolides, and the like are known. In the reaction, the reaction with the amino group having R ₃ or R ₇ in the compound represented by the general formula (1) or the compound represented by the general formula (2) by heating from the first coloring temperature range to a higher temperature range And what is necessary is just to form a -CONH- bond. For the acylating agent according to the present invention, an isocyanate compound and a carboxylic acid hydrazide derivative represented by the above general formula (3) are preferably used.

  Specific examples of the isocyanate compound used as the acylating agent according to the present invention include the following. 2,6-dichlorophenyl isocyanate, p-chlorophenyl isocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1,3-dimethylbenzene-4,6-diisocyanate, 1,4 -Dimethylbenzene-2,5-diisocyanate, 1-methoxybenzene-2,4-diisocyanate, 1-methoxybenzene-2,5-diisocyanate, 1-ethoxybenzene-2,4-diisocyanate 2,5-dimethoxybenzene-1,4-diisocyanate, 2,5-diethoxybenzene-1,4-diisocyanate, 2,5-dibutoxybenzene-1,4-diisocyanate, azobenzene- 4,4'-diisocyanate, diphenyl ether-4,4'-diisocyanate, naphthalene-1,4- Diisocyanate, naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate, naphthalene-2,7-diisocyanate,

  3,3'-dimethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, 3,3'-dichlorobiphenyl-4,4'-diisocyanate 3,3 ', 6,6'-tetrachlorobiphenyl-4,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenyldimethylmethane-4,4'-diisocyanate, benzophenone- 3,3'-diisocyanate, fluorene-2,7-diisocyanate, anthraquinone-2,6-diisocyanate, 9-ethylcarbazole-3,6-diisocyanate, pyrene-3,8-di Isocyanate, naphthalene-1,3,7-triisocyanate, biphenyl-2,4,4'-triisocyanate, 4,4 ', 4 "-tri Sodium triphenylamine, 4,4 ′, 4 ″ -triisocyanate-2,5-dimethoxytriphenylamine, pN, N-dimethylaminophenyl isocyanate, 5,7-diisocyanate-1,1 -Dimethyl-6-n-propylindane, 5,7-diisocyanate-1,1,4,6-tetramethylindane, tris (4-phenylisocyanate) thiophosphate, and the like.

  These isocyanate compounds may be used in the form of so-called block isocyanate, which is an addition compound with phenols, lactams, oximes, etc., if necessary. Diisocyanate dimers such as 1 -You may use it as the isocyanurate which is a dimer and a trimer of methylbenzene-2,4- diisocyanate. Furthermore, it can be used as a polyisocyanate reacted with various polyols, for example, tolylene diisocyanate and trimethylolpropane. Moreover, the dimer and trimer of block isocyanate, diisocyanate, and polyisocyanate may be used alone or in combination of two or more.

  Further, specific examples of the carboxylic acid hydrazide derivative represented by the general formula (3) used as the acylating agent according to the present invention include those represented by Chemical Formula 4 and Chemical Formula 5, but the present invention includes It is not limited.

  The acylating agents represented by the above chemical formulas 4 and 5 may be used alone or in combination of two or more. Moreover, you may use together with the acylating agent containing the said isocyanate compounds other than the said carboxylic acid hydrazide derivative.

  Further, the addition amount of the acylating agent in the present invention is equal to or more than the total amount of the acyl group in the isocyanate group or carboxylic acid hydrazide derivative as the active group, more preferably 1.5 times the dye precursor. More than the amount is good. When the addition amount of the acylating agent is less than the equivalent amount with respect to the dye precursor, a part of the dye precursor is not acylated, so that the color tone is mixed by heating from the first color development temperature range to a higher temperature range. This is not preferable.

  The two-color thermosensitive coloring material of the present invention may contain a thermofusible substance in order to improve its thermal response. The heat-fusible substance preferably used in the present invention has a melting point of about 60 to 180 ° C., and a heat-fusible substance having a melting point of 80 to 140 ° C. is particularly suitable.

  Specific examples of heat-fusible substances include stearic acid amide, N-hydroxymethyl stearic acid amide, N-stearyl stearic acid amide, ethylene bis stearic acid amide, N-stearyl urea, benzyl-2-naphthyl ether, m-terphenyl, 4-benzylbiphenyl, 1,2-bis (phenoxymethyl) benzene, 2,2'-bis (4-methoxyphenoxy) diethyl ether, α, α'-diphenoxyxylene, bis (4-methoxy Phenyl) ether, diphenyl adipate, dibenzyl oxalate, di (4-chlorobenzyl) ester oxalate, di (4-methylbenzyl) ester oxalate, 1,2-bis (3-methylphenoxy) ethane, 1,2-diphenoxy Ethane, dimethyl terephthalate, dibenzyl terephthalate, benzenesulfur Known heat-fusible substances such as phosphonic acid phenyl ester, diphenylsulfone, bis (4-allyloxyphenyl) sulfone, 4-acetylacetophenone, acetoacetate anilides, fatty acid anilides and the like can be mentioned. These compounds may be used independently and may use 2 or more types together. Moreover, in order to obtain sufficient thermal responsiveness, it is preferable that the heat fusible substance occupies 5 to 50% by mass in the total solid content of the two-color thermosensitive coloring material.

  If necessary, pigments, sensitizers, binders, antioxidants and the like may be added to the two-color thermosensitive coloring material of the present invention.

  Examples of the pigment used in the two-color thermosensitive coloring material of the present invention include diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, titanium dioxide, zinc oxide, silicon oxide, aluminum oxide, aluminum hydroxide, urea-formalin resin. And inorganic or organic pigments.

  Examples of the binder used in the two-color thermosensitive coloring material of the present invention include starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, sodium polyacrylate, acrylic acid amide / acrylic acid ester Polymers, water-soluble binders such as acrylic acid amide / acrylic acid ester / methacrylic acid terpolymers, alkali salts of styrene / maleic anhydride copolymers, alkali salts of ethylene / maleic anhydride copolymers, polyacetic acid And latexes such as vinyl, polyurethane, polyacrylate, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer, methyl acrylate / butadiene copolymer, and ethylene / vinyl acetate copolymer. That.

  As other additives, dispersants such as sodium dioctylsulfosuccinate, ultraviolet absorbers such as benzophenone and benzotriazole, surfactants, fluorescent dyes and the like can be added as necessary.

  The two-color thermosensitive coloring material of the present invention is capable of giving a black-red two-color or a blue-red two-color from a substantially colorless (white) state to a temperature higher than the first coloring temperature range. If it can be heated, it can be used after being processed into a sheet form or a pellet form regardless of the form, but by providing the two-color thermosensitive coloring material of the present invention on a support, it can be used for conventional thermosensitive recording materials. Image recording using a recording device can also be performed.

As the support used for laminating the two-color thermosensitive coloring material of the present invention, paper is mainly used, but woven fabric, non-woven fabric, plastic film, synthetic paper, metal foil, glass plate, etc., or a composite sheet combining these Can be used arbitrarily. The coating amount of the two-color thermosensitive coloring material on the support is suitably from 0.1 to 2.0 g / m ^{2 in} terms of the amount of the dye precursor which is a coloring component in the ^two- color thermosensitive coloring material.

  When performing image recording on a two-color thermosensitive recording material provided with the two-color thermosensitive coloring material of the present invention on a support using a conventional recording apparatus for thermal recording material, wear prevention or sticking prevention of the heated print head For the purpose of, etc., waxes such as higher fatty acid metal salts such as zinc stearate and calcium stearate, paraffin, oxidized paraffin, polyethylene, oxidized polyethylene, stearamide, and custard wax are added to the two-color thermosensitive coloring material as necessary. can do.

  When the two-color thermosensitive coloring material of the present invention is provided on the support, the two-color thermosensitive coloring material is used to improve the coating property or adhesiveness of the two-color thermosensitive coloring material and to adjust the thermal response of the two-color thermosensitive recording material. In order to provide a single layer or multiple undercoat layers (intermediate layer) between the layer and the support, or to protect the two-color heat-sensitive color developing material layer, a single layer or a plurality of layers on the two-color heat-sensitive color developing material layer Or a recording layer containing the two-color thermosensitive coloring material of the present invention, or a charging layer on the opposite side of the two-color thermosensitive coloring material layer forming surface of the support. Various known techniques in the production of conventional heat-sensitive recording materials can be used, such as providing a backing layer such as a prevention layer and a curl correction layer. Further, when the undercoat layer or the two-color thermosensitive coloring material layer is provided on the support, the support surface may be subjected to an activation treatment such as flame treatment or corona treatment.

  Furthermore, the two-color thermosensitive coloring material of the present invention may be used by being attached to one side or both sides of a support provided with various layers on one side or both sides. On one or both sides of the support to which the two-color thermosensitive coloring material of the present invention is attached, an undercoat layer or a backing layer composed of a single layer or a plurality of layers as described above may be provided.

  In the undercoat layer in the present invention, a pigment and a binder are mainly used. In general, the pigment used for the undercoat layer includes calcined kaolin, but other than that, diatomaceous earth, talc, kaolin, heavy calcium carbonate, precipitated calcium carbonate, magnesium carbonate, zinc oxide, aluminum oxide, hydroxide Inorganic pigments such as aluminum, magnesium hydroxide, titanium dioxide, barium sulfate, zinc sulfate, amorphous silica, amorphous calcium silicate, colloidal silica, melamine resin filler, urea-formalin resin filler, polyethylene powder, nylon powder, etc. An organic pigment is mentioned.

  Examples of the binder used for the undercoat layer include various water-soluble resins or water-dispersible resins that are used in ordinary coating. For example, starches, hydroxymethylcellulose, methylcellulose, ethylcellulose, carboxymethylcellulose, gelatin, casein, modified or unmodified polyvinyl alcohol, sodium alginate, polyvinylpyrrolidone, polyacrylamide, acrylamide / acrylate ester copolymer, acrylamide / acrylate ester / Methacrylic acid terpolymer, alkali salt of polyacrylic acid, alkali salt of polymaleic acid, alkali salt of styrene / maleic anhydride copolymer, alkali salt of ethylene / maleic anhydride copolymer, isobutylene / maleic anhydride Water-soluble resins such as alkali salts of acid copolymers, styrene / butadiene copolymers, acrylonitrile / butadiene copolymers, methyl acrylate / butadiene copolymers, acrylic resins Nitrile / butadiene / styrene terpolymer, polyvinyl acetate, vinyl acetate / acrylate copolymer, ethylene / vinyl acetate copolymer, polyacrylate ester, styrene / acrylate copolymer, polyurethane, etc. Water dispersible resin etc. are mentioned.

The coating amount of the undercoat layer is preferably ^{1~30g / m 2, 3~20g / m} 2 is more preferable. Further, when a plurality of undercoat layers are provided, the layer composition may be the same or different as long as the total coating amount is in the above range.

The two-color thermosensitive coloring material of the present invention is provided with at least one protective layer mainly composed of at least one selected from a water-soluble resin, a water-dispersible resin, and an organic solvent-soluble resin, thereby providing image storability. Among them, water-soluble resins and water-dispersible resins are preferably used. Moreover, you may use resin which forms a film | membrane with an electron beam and an ultraviolet-ray. Dry coating amount of the protective layer is preferably ^{0.2~10g / m 2, 0.5~5g / m} 2 is more preferable.

  Examples of the water-soluble resin or water-dispersible resin for the protective layer include conventionally known water-soluble polymers or water-dispersible resins. Examples of water-soluble resins include modified or unmodified polyvinyl alcohol, starch or derivatives thereof, cellulose derivatives such as hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, polyvinyl pyrrolidone, polyacrylamide, acrylamide / acrylic acid ester copolymers, Acrylamide / acrylic acid ester / methacrylic acid terpolymer, alkali salt of polyacrylic acid, alkali salt of polymaleic acid, alkali salt of styrene / maleic anhydride copolymer, alkali salt of ethylene / maleic anhydride copolymer, Examples include alkali salts of isobutylene / maleic anhydride copolymer, sodium alginate, gelatin, casein, and acid neutralized products of chitosan.

  Examples of water dispersible resins include styrene / butadiene copolymers, acrylonitrile / butadiene copolymers, methyl acrylate / butadiene copolymers, acrylonitrile / butadiene / styrene terpolymers, polyvinyl acetate, vinyl acetate / Examples thereof include acrylic acid ester copolymers, ethylene / vinyl acetate copolymers, polyacrylic acid esters, styrene / acrylic acid ester copolymers, and polyurethanes.

  In the protective layer, a pigment can be used in combination for the purpose of improving the recording running property, writing property and the like. Specific examples of pigments used in the protective layer include diatomaceous earth, talc, kaolin, calcined kaolin, heavy calcium carbonate, precipitated calcium carbonate, magnesium carbonate, zinc oxide, aluminum oxide, aluminum hydroxide, magnesium hydroxide, titanium dioxide, sulfuric acid Examples thereof include inorganic pigments such as barium, zinc sulfate, amorphous silica, amorphous calcium silicate, colloidal silica, and organic pigments such as melamine resin filler, urea-formalin resin filler, polyethylene powder, and nylon powder.

  The protective layer has a higher fatty acid metal salt such as zinc stearate and calcium stearate, a higher fatty acid amide such as stearic acid amide, paraffin, polyethylene wax, and oxidation for the purpose of improving the recording runnability such as head wear prevention and sticking prevention. A lubricant such as polyethylene and castor wax, and an ultraviolet absorber may be added as necessary.

  The conventional additive type two-color coloring system performs red or blue coloring printing with low energy and black coloring printing with high energy, so energy is required for black coloring often used for normal information recording, Although it was a cause of shortening the life of the printer head, the thermal recording material provided with the two-color coloring material of the present invention on the support has a black or blue color of the first color lower than that of a normal thermal recording material. Can be printed with high energy, and the red color as a highlight can be printed with high energy, which leads to power saving, which is advantageous in terms of energy cost and driving time of the portable terminal, and also increases the life of the printer head. It can be extended.

  Next, the present invention will be described in more detail with reference to examples. However, it is not limited to these. The parts and% shown below are based on mass, and the coating amount is the absolute dry coating amount.

Example 1
(A) Preparation of a dispersion for forming a two-color thermosensitive color forming material 30% of 3-di-n-butylamino-6-methyl-7-anilino-fluorane, which is a dye precursor having a black color tone, is 2.5%. The mixture was pulverized in a ball mill for 24 hours together with 69 parts of an aqueous polyvinyl alcohol solution to obtain a dye precursor dispersion. Next, 45 parts of an acylating agent, diphenylmethane-4,4'-diisocyanate, was pulverized with a ball mill for 1 hour together with 100 parts of a 2.5% aqueous polyvinyl alcohol solution to obtain an acylating agent dispersion. Finally, 70 parts of salicylic acid as a developer was pulverized with a sand mill together with 420 parts of a 2.5% polyvinyl alcohol aqueous solution to obtain a dispersion containing a developer having a volume average particle diameter of 2 μm or less. After mixing the above three types of dispersions, the following additives were added and mixed well with stirring to prepare a dispersion for forming a two-color thermosensitive coloring material.
50% calcium carbonate aqueous dispersion 180 parts 40% zinc stearate aqueous dispersion 25 parts 10% polyvinyl alcohol aqueous solution 272 parts water 300 parts

(B) Preparation of support for laminating two-color thermosensitive color-developing material A coating liquid comprising the following composition was coated on a high-quality paper having a basis weight of 40 g / m ^{2 so} that the solid content was 9 g / m ² . dried to produce a two-color heat sensitive color developing material laminated support.
Baked kaolin 100 parts 50% styrene / butadiene copolymer latex aqueous dispersion 24 parts water 200 parts

(C) Preparation of two-color thermosensitive coloring material The dispersion for forming the two-color thermosensitive coloring material prepared in (A) is applied on the support for laminating the two-color thermosensitive coloring material prepared in (B). There coated so that 5 g / m ^2, and dried to obtain a two-color heat sensitive color developing material.

Example 2
In Example 1, except that the dye precursor 3-di-n-butylamino-6-methyl-7-anilino-fluorane was changed to the same amount of 3-diethylamino-6-methyl-7-anilino-fluorane. A two-color thermosensitive coloring material was produced in the same manner as in Example 1.

Example 3
A two-color thermosensitive coloring material was prepared in the same manner as in Example 2 except that salicylic acid as the developer was changed to 4,4'-dihydroxydiphenylsulfone in the same amount in Example 2.

Example 4
In Example 2, a two-color thermosensitive coloring material was produced in the same manner as in Example 2 except that salicylic acid as the developer was changed to the same amount of 1,1-bis (p-hydroxyphenyl) propane.

Example 5
In Example 2, salicylic acid as a developer was changed to N- (4-methylphenylsulfonyl) -N ′-[3- (4-methylphenylsulfonyloxy) phenyl] urea in the same amount. In the same manner as in No. 2, a two-color thermosensitive coloring material was produced.

Example 6
In Example 2, a two-color thermosensitive coloring material was produced in the same manner as in Example 2 except that salicylic acid as the developer was changed to the same amount of the compound described in Chemical formula 6 below.

Example 7
In Example 2, the same procedure as in Example 2 was conducted except that the acylating agent diphenylmethane-4,4′-diisocyanate was changed to the same amount of 4,4 ′, 4 ″ -triisocyanate triphenylamine. A two-color thermosensitive coloring material was produced.

Example 8
In Example 2, except that the acylating agent diphenylmethane-4,4′-diisocyanate was changed to the same amount of 4,4 ′, 4 ″ -triisocyanate-2,5-dimethoxytriphenylamine, A two-color thermosensitive coloring material was prepared in the same manner as in Example 2.

Example 9
In Example 2, the same procedure as in Example 2 was performed except that the acylating agent diphenylmethane-4,4′-diisocyanate was changed to the same amount of the carboxylic acid hydrazide derivative (3-3) described in Chemical Formula 4 above. A two-color thermosensitive coloring material was produced.

Example 10
In Example 2, the same procedure as in Example 2 was repeated, except that the acylating agent diphenylmethane-4,4′-diisocyanate was changed to the same amount of the carboxylic acid hydrazide derivative (3-9) described in Chemical Formula 5 above. A two-color thermosensitive coloring material was produced.

Comparative Example 1
In Example 1, the dye precursor 3-di-n-butylamino-6-methyl-7-anilino-fluorane was changed to the same amount of 3-diethylamino-6-methyl-7-dibenzylamino-fluorane. Except for the above, a thermosensitive coloring material was prepared in the same manner as in Example 1.

Comparative Example 2
In Example 2, a thermosensitive coloring material was prepared in the same manner as in Example 2 except that the acylating agent dispersion was not added.

  The Beck smoothness of the two-color thermochromic material surface in the two-color thermochromic material prepared in Examples 1 to 10 and the thermochromic material surface in the thermochromic material prepared in Comparative Examples 1 and 2 is 400 to 500 seconds, respectively. The calendar was processed so that

Test 1 (Black color test)
A printing test was performed using a facsimile testing machine TH-PMD manufactured by Okura Electric. When a thermal head having a dot density of 8 dots / mm and a head resistance of 185 Ω was used and energized at a head voltage of 12 V, a pulse width of 0.8, and 1.0 milliseconds, printing was carried out. Both of Comparative Examples 1 and 2 gave clear black-green to black color developed images.

Test 2 (Red color development test)
When the thermal stamp set at 150 ° C. was contacted at a pressure of 98 kN / m ² for 2 seconds, any of Examples 1 to 10 of the present invention gave a clear red color image. In contrast, Comparative Examples 1 and 2 did not give a red color image, but merely gave a black-green to black color image.

Example 11
In Example 1, 3-di-n-butylamino-6-methyl-7-anilino-fluorane, which is a dye precursor, is added to 4-anilino-8, which is the same amount of a dye precursor having a blue color tone. A two-color thermosensitive coloring material was prepared in the same manner as in Example 1 except that -di-n-butylamino-benzo [a] -fluorane was used.

Example 12
In Example 11, the dye precursor 4-anilino-8-di-n-butylamino-benzo [a] -fluorane was changed to the same amount of 4-anilino-8-diethylamino-benzo [a] -fluorane. Except for this, a two-color thermosensitive coloring material was prepared in the same manner as in Example 11.

Example 13
A two-color thermosensitive coloring material was prepared in the same manner as in Example 12 except that salicylic acid as the developer was changed to 4,4'-dihydroxydiphenylsulfone in the same amount in Example 12.

Example 14
A two-color thermosensitive coloring material was produced in the same manner as in Example 12 except that salicylic acid as the developer was changed to 1,1-bis (p-hydroxyphenyl) propane of the same amount in Example 12.

Example 15
In Example 12, salicylic acid as the developer was changed to the same amount of N- (4-methylphenylsulfonyl) -N ′-[3- (4-methylphenylsulfonyloxy) phenyl] urea. In the same manner as in No. 12, a two-color thermosensitive coloring material was produced.

Example 16
In Example 12, a two-color thermosensitive coloring material was produced in the same manner as in Example 12 except that salicylic acid as the developer was changed to the same amount of the compound described in Chemical Formula 6 .

Example 17
In Example 12, the same procedure as in Example 12 was carried out except that the acylating agent diphenylmethane-4,4′-diisocyanate was changed to the same amount of 4,4 ′, 4 ″ -triisocyanate triphenylamine. A two-color thermosensitive coloring material was produced.

Example 18
In Example 12, except that the acylating agent diphenylmethane-4,4′-diisocyanate was changed to the same amount of 4,4 ′, 4 ″ -triisocyanate-2,5-dimethoxytriphenylamine, A two-color thermosensitive coloring material was produced in the same manner as in Example 12.

Example 19
In Example 12, the same procedure as in Example 12 was carried out except that the acylating agent diphenylmethane-4,4′-diisocyanate was changed to the same amount of the carboxylic acid hydrazide derivative (3-3) described in Chemical Formula 4 above. A two-color thermosensitive coloring material was produced.

Example 20
In Example 12, the same procedure as in Example 12 was carried out except that the acylating agent diphenylmethane-4,4′-diisocyanate was changed to the same amount of the carboxylic acid hydrazide derivative (3-9) described in Chemical Formula 5 above. A two-color thermosensitive coloring material was produced.

Comparative Example 3
In Example 11, the dye precursor 4-anilino-8-di-n-butylamino-benzo [a] -fluorane was used in the same amount of 3,3-bis (4-dimethylaminophenyl) -6-dimethylamino. A thermosensitive coloring material was produced in the same manner as in Example 11 except that phthalide (crystal violet lactone) was used.

Comparative Example 4
In Example 11, the dye precursor 4-anilino-8-di-n-butylamino-benzo [a] -fluorane was added to the same amount of 3- (4-diethylamino-2-ethoxyphenyl) -3- (1. A thermosensitive coloring material was prepared in the same manner as in Example 11 except that -ethyl-2-methylindol-3-yl) azaphthalide was used.

Comparative Example 5
In Example 12, a thermosensitive coloring material was produced in the same manner as in Example 12 except that the acylating agent dispersion was not added.

  The Beck smoothness of the two-color thermochromic material surface in the two-color thermochromic material prepared in Examples 11 to 20 and the thermochromic material surface in the thermochromic material prepared in Comparative Examples 3 to 5 is 400 to 500 seconds, respectively. The calendar was processed so that

Test 1 (blue color development test)
A printing test was performed using a facsimile testing machine TH-PMD manufactured by Okura Electric. When using dot density 8 dots / mm, a thermal head of the head resistance 185 [Omega], was printed by energizing the head voltage 12V, pulse width 0.8, and 1.0 ms, examples 11 to 20 of the present invention, All of Comparative Examples 3 to 5 gave clear blue-colored images.

Test 2 (Red color development test)
When the thermal stamp set at 150 ° C. was contacted at 98 kN / m ² for 2 seconds, any of Examples 11 to 20 of the present invention gave a clear red color image. In contrast, Comparative Examples 3 to 5 did not give a red color image, but merely gave a blue color image.

Claims (1)

As an electron-donating compound represented by the following general formula (1) or an electron-donating compound represented by the following general formula (2), which is usually colorless or light , 3-di-n-butylamino-6-methyl- 7-anilino-fluorane, 3-diethylamino-6-methyl-7-anilino-fluorane, 4-anilino-8-di-n-butylamino-benzo [a] -fluorane and 4-anilino-8-diethylamino-benzo [ a] -fluorane, an electron-accepting developer that causes the compound to develop color by heating to the first coloring temperature range, and R _{3 of the} compound by heating to a temperature higher than the first coloring temperature range. or of reacting with an amino group having R _7, by forming a -CONH- bond, as an acylating agent allowed to discolor color tone of the compound, diphenylmethane-4,4'-diiso Anato, 4,4 ', 4 "-triisocyanatotriphenylamine, 4,4', 4" -triisocyanate-2,5-dimethoxytriphenylamine and carboxylic acid represented by the following general formula (3) A two-color thermosensitive coloring material comprising a compound selected from hydrazide derivatives.

(In Formula 1, R ₁ and R ₂ each represent a hydrogen atom, an alkyl group, an alkenyl group, an alicyclic group, an aralkyl group, an aryl group, or a heterocyclic residue, and R ₁ and R ₂ represent a direct or linking group. R ₃ represents an aryl group, R ₄ represents a hydrogen atom or an alkyl group.

(In Formula 2, R ₅ and R ₆ each represent a hydrogen atom, an alkyl group, an alkenyl group, an alicyclic group, an aralkyl group, an aryl group, or a heterocyclic residue, and R ₅ and R ₆ represent a direct or linking group. R ₇ represents an aryl group, and —NHR ₇ is substituted at the 2-position or 4-position.

(In Formula 3, R ₈ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or an aryl group.)