JP2012125966A - Reversible thermal recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reversible thermal recording material which retains a temporally stable image even under a high-temperature environment with an excellent color developing property and erasability.SOLUTION: The reversible thermal recording material includes a reversible thermal recording layer provided on a support, the layer containing a dye precursor which is generally colorless or hypochromic and a reversible developer which forms a relatively colored state and an erased state by a difference in heating temperature and/or cooling rate after heating. The reversible thermal recording layer contains a linear amine compound represented by general formula (2) as well as the reversible developer represented by general formula (1).

Description

  The present invention relates to a reversible thermosensitive recording material whose color tone reversibly changes by controlling thermal energy.

  In recent years, a reversible thermosensitive recording material that can form a temporary image and erase the image when it is no longer needed attracts attention. As a reversible thermosensitive recording material, usually a colorless or light dye precursor and a reversible color developer (hereinafter referred to as reversible developer) that develops color by heating the dye precursor and re-heats it to decolorize it. A heat-sensitive recording material using a colorant) (see, for example, Patent Documents 1 and 2), a heat-sensitive recording material in which an organic low-molecular substance such as a higher fatty acid is dispersed in a resin such as vinyl chloride-vinyl acetate, and a different refractive index. A heat-sensitive recording material in which two or more kinds of polymers are mixed is known.

  In a reversible thermosensitive recording material usually composed of a colorless or light dye precursor and a reversible developer, an organic phosphonic acid compound, α-hydroxy aliphatic carboxylic acid, fatty acid dicarboxylic acid, gallic acid as a reversible developer. Compounds such as alkyl esters and ascorbic acid derivatives are exemplified (see, for example, Patent Document 3). However, this recording medium cannot solve the two problems of low color density and incomplete erasing at the same time, and the image storage stability under a high temperature environment is not satisfactory in practice.

On the other hand, a phenol compound having a long-chain alkyl group has been found to be effective as a reversible developer, and has been proposed as a highly practical reversible thermosensitive recording material (see, for example, Patent Document 4). According to such a recording material, a high-contrast and high-sensitivity recorded image can be formed and erased many times, and widely used for the purpose of visualizing information in the card in a medium such as an IC card or a magnetic card. It has come to be. It has been proposed that a specific erasing accelerator is added to such a reversible thermosensitive recording material to obtain high-speed erasing properties. However, there are problems such as erasability and insufficient image storability in a high temperature environment. (For example, refer to Patent Document 5).

  Also, reversible thermosensitive recording material with good erasability by containing an amine compound, amide compound, ammonium compound, imide compound, phosphonium compound, carboxylic acid hydrazide compound, or sulfonium compound as a decoloring regulator in the reversible thermosensitive recording material. Although materials can be obtained (see, for example, Patent Documents 6 and 7), even in such a reversible thermosensitive recording material, image storability in a high temperature environment is still insufficient.

Japanese Patent Laid-Open No. 6-210954 JP 2000-263946 A JP-A-5-124360 JP 2005-1127 A JP 2000-313171 A JP 2000-263945 A JP 2001-162941 A

  An object of the present invention is to provide a reversible thermosensitive recording material that retains a stable image over time even in a high temperature environment and is excellent in color development and decoloring properties.

  As a result of examining the constitution of the heat-sensitive recording layer of the reversible thermosensitive recording material in order to solve these problems, the present inventors have found that the above-described problems can be solved by the following invention.

  Contains a normally colorless or light-colored dye precursor on a support and a reversible developer that forms a relatively colored state and a decolored state due to differences in heating temperature and / or cooling rate after heating. In the reversible thermosensitive recording material provided with the reversible thermosensitive recording layer, the reversible thermosensitive recording layer contains a reversible developer represented by the following general formula (1), and is represented by the following general formula (2). A reversible thermosensitive recording material containing the linear amine compound represented.

In the general formula (1), R ¹ represents a linear hydrocarbon group having 20 to 32 carbon atoms, and X represents an amide group or a urea group.

In the general formula (2), R ² represents a linear hydrocarbon group having 20 to 32 carbon atoms, and R ³ and R ⁴ represent a hydrogen atom or a methyl group.

  According to the present invention, it is possible to provide a reversible thermosensitive recording material that retains a stable image over time even in a high temperature environment and is excellent in color development and decoloring properties.

  The reversible thermosensitive recording material of the present invention will be described in detail below. The reversible thermosensitive recording material of the present invention generally has a colorless or light dye precursor on at least one side of the support, and the above-described general reversible color change in the dye precursor due to the difference in cooling rate after heating. A reversible thermosensitive recording material provided with a thermosensitive recording layer comprising a reversible developer represented by the formula (1) contains a linear amine compound represented by the general formula (2). It is characterized by that. When the compounds represented by the general formulas (1) and (2) are used in combination, a reversible thermosensitive recording material having good heat-resistant storage stability of the image area when stored in a high temperature environment can be obtained.

  In the reversible thermosensitive recording material of the present invention, the reversible developer has a relatively long-chain hydrocarbon group in its structure, so it has low compatibility with the dye precursor and is almost soluble in each other at room temperature. It is not considered. Further, in a state where the dye precursor and the reversible developer can freely move as in the heat-melted state, the dye precursor and the reversible developer are melted at a certain ratio to form a color state. When the colored mixture that has developed color is slowly cooled, the reversible developer and the dye precursor become insoluble and phase-separate and decolorize as the temperature decreases. On the other hand, if the cooling is performed rapidly, the colored state is stably maintained because it solidifies before phase separation.

  The compound of formula (2) (linear amine compound) according to the present invention inhibits the interaction between linear alkyl groups in the reversible developer, that is, crystallization, and develops a colored state even in a high temperature environment. Is considered to be kept stable.

  The reversible thermosensitive recording material of the present invention contains a phenol compound represented by the general formula (1) as a reversible developer in the reversible thermosensitive recording layer.

In the general formula (1), R ¹ represents a linear hydrocarbon group having 20 to 32 carbon atoms. Preferably it is 22-24. If it is less than 22, the color erasability deteriorates. If it exceeds 32, the heat-resistant storage stability of the image area is not sufficient, and the use in a high-temperature environment is restricted, and the erasing speed at the time of erasing hot air becomes slow. X represents an amide group (—CONH—, —NHCO—) or a urea group (—NHCONH—).

  Specific examples of the reversible developer represented by the general formula (1) are given below, but the present invention is not limited thereto.

  N- [2- (p-hydroxyphenyl) ethyl] icosanamide, N- [2- (p-hydroxyphenyl) ethyl] henicosanamide, N- [2- (p-hydroxyphenyl) ethyl] docosanamide, N- [2- (p-hydroxyphenyl) ethyl] tricosanamide, N- [2- (p-hydroxyphenyl) ethyl] tetracosanamide, N- [2- (p-hydroxyphenyl) ethyl] pentacosanamide, N -[2- (p-hydroxyphenyl) ethyl] hexacosanamide, N- [2- (p-hydroxyphenyl) ethyl] heptacosanamide, N- [2- (p-hydroxyphenyl) ethyl] octacosanamide, N- [2- (p-hydroxyphenyl) ethyl] nonacosanamide, N- [2- (p-hydroxyphenyl) e Le] triacontyl Tan amide.

  N-icosyl- [3- (p-hydroxyphenyl)] propionamide, N-henicosyl- [3- (p-hydroxyphenyl)] propionamide, N-docosyl- [3- (p-hydroxyphenyl)] propionamide N-tricosyl- [3- (p-hydroxyphenyl)] propionamide, N-tetracosyl- [3- (p-hydroxyphenyl)] propionamide, N-pentacosyl- [3- (p-hydroxyphenyl)] propion Amide, N-hexacosyl- [3- (p-hydroxyphenyl)] propionamide, N-heptacosyl- [3- (p-hydroxyphenyl)] propionamide, N-octacosyl- [3- (p-hydroxyphenyl)] Propionamide, N-nonacosyl- [3- (p-hydroxyphenyl) ] Propionamide, N- triacontyl - [3- (p-hydroxyphenyl)] propionamide.

  N- [2- (p-hydroxyphenyl) ethyl] -N'-icosylurea, N- [2- (p-hydroxyphenyl) ethyl] -N'-henicosylurea, N- [2- (p-hydroxyphenyl) ) Ethyl] -N'-docosylurea, N- [2- (p-hydroxyphenyl) ethyl] -N'-tricosylurea, N- [2- (p-hydroxyphenyl) ethyl] -N'-tetracosylurea, N- [2- (p-hydroxyphenyl) ethyl] -N'-pentacosylurea, N- [2- (p-hydroxyphenyl) ethyl] -N'-hexacosylurea, N- [2- (p-hydroxyphenyl) ) Ethyl] -N'-heptacosylurea, N- [2- (p-hydroxyphenyl) ethyl] -N'-octacosylurea, N- [2- (p-hydroxyphenyl) ethyl]- '- nonacosyl urea, N- [2- (p- hydroxyphenyl) ethyl]-N'-triacontyl urea.

  Although the synthesis example of the reversible developer represented by the general formula (1) is given below, the present invention is not limited to this.

(Synthesis example)
<Reversible developer; N-docosyl- [3- (p-hydroxyphenyl)] propionamide>
A reaction vessel was charged with 2.5 g of 3- (p-hydroxyphenyl) propionic acid, 6.6 g of behenylamine, 0.4 g of 1-hydroxybentotriazole, 2.3 g of N, N'-diisopropylcarbodiimide, and 300 ml of tetrahydrofuran. Heated at reflux for hours. After cooling the reaction solution to room temperature, the precipitated crystals were filtered off and washed with methanol. The compound was obtained by recrystallization using methanol. Yield 7.8g. The melting point was 107 ° C.

  The amount of the reversible developer used in the present invention is preferably in the range of 5 to 5000% by mass, more preferably 10 to 3000% by mass, based on the dye precursor.

  The reversible thermosensitive recording material of the present invention contains the compound represented by the general formula (2) in the reversible thermosensitive recording layer.

In the general formula (2), R ² is a linear hydrocarbon group having 20 to 32 carbon atoms. Preferably it is 22-24. When it is less than 20, the heat resistant storage stability is not sufficient, and the use in a high temperature environment is restricted. If it exceeds 32, the erasing speed at the time of erasing becomes slow. R ³ and R ⁴ represent a hydrogen atom or a methyl group, and R ³ and R ⁴ may be the same or different.

  In addition, the balance of the alkyl chain length between the reversible developer and the compound represented by the general formula (2) is also important. If the alkyl chain of the reversible developer is longer, the decoloring property is improved, and if the alkyl chain of the compound represented by the general formula (2) is longer, the heat resistant storage stability of the image area is improved. It is preferable that the carbon number difference of both alkyl chains is 0-8 or less, More preferably, it is 0-4 or less, More preferably, it is 0-2 or less. Outside this range, the balance between heat-resistant storage stability and color erasability may not be maintained.

  Although the specific example of a compound represented by General formula (2) below is given, this invention is not limited to this.

  Icosylamine, henocosylamine, docosylamine, tricosylamine, tetracosylamine, pentacosylamine, hexacosylamine, heptacosylamine, octacosylamine, nonacosylamine, triacontylamine, icosylmethylamine, heicosylmethylamine, docosyl Silmethylamine, Tricosylmethylamine, Tetracosylmethylamine, Pentacosylmethylamine, Hexacosylmethylamine, Heptacosylmethylamine, Octacosylmethylamine, Nonacosylmethylamine, Triacontylmethylamine, Icosyl dimethylamine, henocosyl dimethylamine, docosyl dimethylamine, tricosyl dimethylamine, tetracosyl dimethylamine, pentacosyl dimethylamine, hexacosyl dimethylamine Emissions, hepta cosyl dimethylamine, octa cosyl dimethylamine, Roh Naco sill dimethylamine, triacontyl dimethylamine, and the like.

  The compound represented by the general formula (2) of the image portion according to the present invention may be used alone or in combination of two or more. The amount used with respect to the reversible developer is preferably 0.001 to 20% by mass, more preferably 0.005 to 5% by mass, and still more preferably 0.01 to 1% by mass. If it is less than 0.001% by mass, the heat resistant storage stability of the image area is not sufficient, and the use in a high temperature environment may be restricted. When the amount exceeds 20% by mass, problems such as a decrease in color density and poor decoloring occur, and further problems occur in appearance when processed at a temperature higher than the melting point during hot pressing to produce a bonded card. There is.

  The compound represented by the general formula (2) according to the present invention is a raw material for the reversible developer, and remains during the synthesis of the reversible developer, so that it is not washed and recrystallized during the synthesis of the developer. It is good to leave it. In this case, the residual ratio of the compound represented by the general formula (2) of the present invention can be measured by a gas chromatography method, a high performance liquid chromatography method, an NMR method or the like.

  The reversible thermosensitive recording material of the present invention preferably contains an erasure accelerator for the purpose of improving erasability. Although a preferable example is shown below, this invention is not limited to this.

  1,1-dimethyl-4-dodecyl semicarbazide, 1,1-dimethyl-4-octadecyl semicarbazide, 1,1-diethyl-4-icosyl semicarbazide, 1,1-dipropyl-4-tetracosyl semicarbazide, 1,1 -Diethyl-4-nonacosyl semicarbazide, 1-methyl-1-propyl-4-hexatriacontyl semicarbazide.

  N- (1-pyrrolidinyl) -N'-dodecylurea, N- [1- (3-methyl) imidazolio] -N'-tetradecylurea, N- (1-pyrazolyl) -N'-octadecylurea, N- ( 3-thiazolidinio) -N'-octadecylurea, N- (1-pyrrolyl) -N'-icosylurea, N- (1-imidazolyl) -N'-tetracosylurea, N- (1-pyrrolidinyl) -N'- Nonacosyl urea, N- (1-pyrrolyl) -N'-hexatriacontyl urea.

  N- (1-piperidyl) -N′-dodecylurea, N- (1-piperidyl) -N′-tetradecylurea, N- [1- (2,6-dimethyl) piperidyl] -N′-pentadecylurea, N -(4-morpholinyl) -N'-octadecylurea, N- (4-morpholinyl) -N'-icosylurea, N- [4- (2,6-dimethyl) morpholinyl] -N'-tetracosylurea, N- (4-thiomorpholinyl) -N′-hexacosyl urea, N- [1- (4-methyl) piperazinyl] -N′-nonacosyl urea, N- [1- (4-methyl) piperazinyl] -N′-triacontyl urea, N- (1-piperazinyl) -N'-hexatriacontylurea, N- (1- (4-methyl) piperazinyl) -N'-octadecylurea.

  The use amount of the erasure accelerator according to the present invention is 0.05 to 1000% by mass, preferably 0.05 to 500% by mass, and more preferably 0.1 to 200% by mass with respect to the dye precursor. If the amount of erasure accelerator is too small relative to the dye precursor, the erasability (erase accelerating property) tends to deteriorate, and conversely if too much erasing accelerator is present, the color density tends to decrease due to the dilution effect.

  Further, the normally colorless or light dye precursor contained in the reversible thermosensitive recording material of the present invention is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a leuco dye or the like is preferable. . As the leuco dye, a fluorane compound or an azaphthalide compound can be preferably used. Hereinafter, although the specific example of a dye precursor is given, this invention is not limited to this.

  2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6- (di-n-butylamino) fluorane, 2-anilino-3-methyl-6- (di-n-amylamino) ) Fluorane, 2-anilino-3-methyl-6- (di-isoamylamino) fluorane, 2-anilino-3-methyl-6- (Nn-propyl-N-methylamino) fluorane, 2-anilino-3 -Methyl-6- (N-isopropyl-N-methylamino) fluorane, 2-anilino-3-methyl-6- (N-isobutyl-N-methylamino) fluorane, 2-anilino-3-methyl-6- ( Nn-amyl-N-methylamino) fluorane, 2-anilino-3-methyl-6- (N-sec-butyl-N-methylamino) fluorane, 2-anilino- -Methyl-6- (Nn-amyl-N-ethylamino) fluorane, 2-anilino-3-methyl-6- (N-isoamyl-N-ethylamino) fluorane, 2-anilino-3-methyl-6 -(Nn-propyl-N-isopropylamino) fluorane, 2-anilino-3-methyl-6- (N-cyclohexyl-N-methylamino) fluorane, 2-anilino-3-methyl-6- (N- Ethyl-p-toluidino) fluoran, 2-anilino-3-methyl-6- (N-methyl-p-toluidino) fluoran.

  2- (m-trichloromethylanilino) -3-methyl-6-diethylaminofluorane, 2- (m-trifluoromethylanilino) -3-methyl-6-diethylaminofluorane, 2- (m-trichloromethyl) Anilino) -3-methyl-6- (N-cyclohexyl-N-methylamino) fluorane, 2- (2,4-dimethylanilino) -3-methyl-6-diethylaminofluorane, 2- (2,4 -Dimethylanilino) -3-methyl-6- (di-n-butylamino) fluorane, 2- (m-toluidino) -3-methyl-6-diethylaminofluorane, 2- (m-toluidino) -3- Methyl-6- (di-n-butylamino) fluorane, 2- (p-toluidino) -3-methyl-6-diethylaminofluorane, 2- (p-toluidino) -3- Tyl-6- (di-n-butylamino) fluorane, 2- (N-ethyl-p-toluidino) -3-methyl-6- (N-ethylanilino) fluorane, 2- (N-ethyl-p-toluidino) -3-methyl-6- (N-propyl-p-toluidino) fluorane, 2-anilino-6- (Nn-hexyl-N-ethylamino) fluorane, 2- (o-chloroanilino) -6-diethylaminofluor Oran, 2- (o-chloroanilino) -6- (di-n-butylamino) fluorane, 2- (m-trifluoromethylanilino) -6-diethylaminofluorane, 2,3-dimethyl-6-dimethylamino Fluorane, 3-methyl-6- (N-ethyl-p-toluidino) fluorane, 2-chloro-6-diethylaminofluorane.

  2-bromo-6-diethylaminofluorane, 2-chloro-6- (di-n-propylamino) fluorane, 3-chloro-6-cyclohexylaminofluorane, 3-bromo-6-cyclohexylaminofluorane, 2- Chloro-6- (N-ethyl-N-isoamylamino) fluorane, 2-chloro-3-methyl-6-diethylaminofluorane, 2-anilino-3-chloro-6-diethylaminofluorane, 2- (o-chloroanilino) ) -3-Chloro-6-cyclohexylaminofluorane, 2- (m-trifluoromethylanilino) -3-chloro-6-diethylaminofluorane, 2- (2,3-dichloroanilino) -3-chloro -6-diethylaminofluorane, 1,2-benzo-6-diethylaminofluorane, 3-diethylamino- - (m-trifluoromethyl) -6-fluoran.

  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-diethylaminophenyl) -7-azaphthalide, 3- (1-octyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4- Azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-methyl-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindole-3- Yl) -3- (2-methyl-4-diethylaminophenyl) -7-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (4-diethyl) Aminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- [4- (Nn-amyl-N-methylamino) phenyl] -4-azaphthalide, 3 -(1-Methyl-2-methylindol-3-yl) -3- (2-hexyloxy-4-diethylaminophenyl) -4-azaphthalide, 3,3-bis (2-ethoxy-4-diethylaminophenyl)- 4-Azaphthalide, 3,3-bis (2-ethoxy-4-diethylaminophenyl) -7-azaphthalide.

  3- (p-Toluidino) -2-methyl-8-dipropylaminofluorane, 3- (p-Toluidino) -2-methyl-8-pyrrolidinofluorane, 2- (p-acetylanilino) -6 -(Nn-amyl-Nn-butylamino) fluorane, 2-benzylamino-6- (N-ethyl-p-toluidino) fluorane, 2-benzylamino-6- (N-methyl-2,4 -Dimethylanilino) fluorane, 2-benzylamino-6- (N-ethyl-2,4-dimethylanilino) fluorane, 2-benzylamino-6- (N-methyl-p-toluidino) fluorane, 2-bis (P-methylbenzylamino) -6- (N-ethyl-p-toluidino) fluorane, 2- (α-phenylethylamino) -6- (N-ethyl-p-toluidino) fluorane.

  2-methylamino-6- (N-methylanilino) fluorane, 2-methylamino-6- (N-ethylanilino) fluorane, 2-methylamino-6- (Nn-propylanilino) fluorane, 2-ethylamino -6- (N-methyl-p-toluidino) fluorane, 2-methylamino-6- (N-methyl-2,4-dimethylanilino) fluorane, 2-ethylamino-6- (N-ethyl-2, 4-dimethylanilino) fluorane, 2-dimethylamino-6- (N-methylanilino) fluorane, 2-dimethylamino-6- (N-ethylanilino) fluorane, 2-diethylamino-6- (N-methyl-p-toluidino ) Fluorane, 2-diethylamino-6- (N-ethyl-p-toluidino) fluorane, 2-di-n-propylamino-6- N- methylanilino) fluoran, 2-di -n- propyl amino-6-(N- ethylanilino) fluoran.

  2-amino-6- (N-methylanilino) fluorane, 2-amino-6- (N-ethylanilino) fluorane, 2-amino-6- (Nn-propylanilino) fluorane, 2-amino-6- ( N-methyl-p-toluidino) fluorane, 2-amino-6- (N-ethyl-p-toluidino) fluorane, 2-amino-6- (Nn-propyl-p-toluidino) fluorane, 2-amino- 6- (N-methyl-p-ethylanilino) fluorane, 2-amino-6- (N-ethyl-p-ethylanilino) fluorane, 2-amino-6- (Nn-propyl-p-ethylanilino) fluorane, 2 -Amino-6- (N-methyl-2,4-dimethylanilino) fluorane, 2-amino-6- (N-ethyl-2,4-dimethylanilino) fluorane, 2 Amino-6- (Nn-propyl-2,4-dimethylanilino) fluorane, 2-amino-6- (N-methyl-p-chloroanilino) fluorane, 2-amino-6- (N-ethyl-p -Chloroanilino) fluoran, 2-amino-6- (Nn-propyl-p-chloroanilino) fluorane, 1,2-benzo-6- (N-ethyl-N-isoamylamino) fluorane, 1,2-benzo- 6-di-n-butylaminofluorane, 1,2-benzo-6- (N-methyl-N-cyclohexylamino) fluorane, 1,2-benzo-6- (N-ethyl-N-toluidino) fluorane.

  4,4'-bis (dimethylaminophenyl) benzhydrylbenzyl ether, N-chlorophenyl leucooramine, N-2,4,5-trichlorophenyl leucooramine, benzoyl leucomethylene blue, p-nitrobenzoyl leucomethylene blue, 3 -Methylspirodinaphthopyrans, 3-ethylspirodinaphthopyrans, 3,3'-dichlorospirodinaphthopyrans, 3-benzylspirodinaphthopyrans, 3-methylnaphthyl (3-methoxybenzo) spiropyrans, 3-propylspiros Benzopyran.

0
These dye precursors may be used singly or in combination of two or more, and toning can also be performed by mixing dye precursors that develop colors in other colors. In addition, a multicolor reversible thermosensitive recording material or a full-color reversible thermosensitive recording material can be obtained by laminating layers that develop colors of different colors or arranging them on a plane. The dye precursor may be subjected to processing such as microencapsulation, resin coating, and composite particle formation with a resin.

  The support according to the present invention includes paper, non-woven fabric / woven fabric / knitted fabric, plastic film, resin-coated paper, synthetic paper, metal plate, metal foil, glass, quartz glass, silicon resin, aluminum oxide, silicon oxide Etc., or a combination of these can be arbitrarily used depending on the purpose. Examples of the plastic film that can be used in the present invention include polyester film, polyolefin film, polyvinyl alcohol film, polyvinyl chloride film, nylon film, polystyrene film, polyvinylidene chloride film, ethylene-vinyl acetate copolymer film, ethylene-vinyl. Examples include alcohol copolymer films, fluororesin films, polyimide films, aromatic polyamide films, acrylic (based) resin films, and polycarbonate films. A polyester film is preferable in terms of mechanical strength, smoothness, water resistance, solvent resistance, and heat resistance. These synthetic resin materials may be used alone or in combination of two or more.

  Examples of the polyester film include polyethylene terephthalate (PET), polybutylene terephthalate, poly-1,4-cyclohexanedimethylene terephthalate, polyxylylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalate (PEN). It is done. Preferred polyester films include PET films or PEN films that are excellent in toughness, heat resistance, chemical resistance, dimensional stability, transparency, and electrical insulation.

  The support may be opaque, translucent or transparent. In order to make the background appear white or other specific colors, a white pigment, a colored dye pigment, or air bubbles may be included in the support or on the surface. When the affinity when a coating layer such as a reversible thermosensitive recording layer is provided on the support is low, the support is obtained by corona discharge treatment, oxidation reaction treatment (chromic acid, etc.), etching treatment, easy adhesion treatment, antistatic treatment, etc. A modification treatment may be performed on the surface. There is no restriction | limiting in particular about a shape, a structure, a magnitude | size, etc. as a support body concerning this invention. Examples of the shape include a flat plate shape and a roll shape. The structure may be a single layer structure or a laminated structure, and the size can be appropriately selected according to the use of the reversible thermosensitive recording material.

  The thickness of the support according to the present invention can be appropriately selected according to the use of the reversible thermosensitive recording material, but is preferably 10 to 2000 μm, and more preferably 20 to 1000 μm.

  The reversible thermosensitive recording layer according to the present invention is formed by coating / forming a reversible thermosensitive recording layer coating solution containing at least a dye precursor and a reversible developer on at least one surface of a support. Is done. As a method for including the dye precursor and the reversible developer in the reversible thermosensitive recording layer coating solution, each compound is dissolved in a solvent alone or dispersed in a dispersion medium and then mixed. Are mixed in a solvent and then dissolved in a solvent or dispersed in a dispersion medium, each compound is heated and dissolved, homogenized and then cooled, dissolved in a solvent or dispersed in a dispersion medium, and the like. It is not something. If necessary, a dispersing agent may be used during dispersion.

  As a solvent or dispersion medium, water; alcohols such as methanol, ethanol, n-propanol, 2-propanol, n-butanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone; methyl acetate, ethyl acetate , Esters such as butyl acetate, isobutyl acetate, isopropyl acetate, ethyl lactate, ethylene carbonate; ethers such as diethyl ether, glycol dimethyl ether, glycol diethyl ether, dioxane, dioxolane, tetrahydrofuran; benzene, toluene, xylene, cresol, styrene, etc. Aromatic hydrocarbons such as pentane, hexane and cyclohexane; methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, Ren chlorohydrin, chlorobenzene, halogenated hydrocarbons such as dichlorobenzene; N, N- dimethylformamide, N, etc. amides such as N- dimethylacetamide can be used.

  For the purpose of improving the strength of the reversible thermosensitive recording layer, it is also possible to add a binder resin to the reversible thermosensitive recording layer. Specific examples of the binder resin include starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid soda, (meth) acrylic acid amide- (meth) acrylic acid ester copolymer Polymer, (meth) acrylic acid amide- (meth) acrylic acid ester- (meth) acrylic acid terpolymer, alkali salt of styrene-maleic anhydride copolymer, alkali salt of ethylene-maleic anhydride copolymer , Polyvinyl acetate, polyurethane, poly (meth) acrylic acid ester, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, methyl (meth) acrylate-butadiene copolymer, ethylene-vinyl acetate copolymer, ethylene -PVC Alcohol copolymer, polyvinyl chloride, ethylene - vinylidene chloride copolymer, polyvinylidene chloride, polycarbonates, polyvinyl butyral, and the like. The role of these binder resins is to keep the materials contained in the reversible thermosensitive recording layer uniformly dispersed without being displaced by heat application for image recording or image erasing. Therefore, it is preferable to use a resin having high heat resistance as the binder resin. When heat resistance, water resistance, and adhesiveness are required, a curable resin is particularly preferable.

  Examples of the curable resin include a thermosetting resin, an electron beam curable resin, and an ultraviolet curable resin. When a thermosetting resin is applied, a liquid containing a crosslinking agent is applied and formed into a film, and then crosslinked by heat. Specific examples of the thermosetting resin include epoxy resins, urea resins, xylene-formaldehyde resins, melamine resins, guanamine resins, phenol resins, phenoxy resins, saturated polyester resins, unsaturated polyester resins, and polyol resins. In addition, examples of the curing agent used in these thermosetting resins include organic acids, amines, isocyanates, epoxies, phenols, and the like. It only has to be selected. Among these, a crosslinked resin obtained by thermally curing a polyol compound with an isocyanate compound described in JP-A Nos. 10-230680 and 11-58963 is preferable.

  As oligomers / monomers used for electron beam curable resins or UV curable resins, there are many types of acrylic oligomers / monomers with excellent radiation curing properties, polyene-thiol oligomers / monomers, and photocationic polymerization type epoxy. Examples include oligomers and monomers. Examples of the acrylic monomer include a monofunctional monomer, a bifunctional monomer, and a polyfunctional monomer. In particular, a photopolymerization initiator and a photopolymerization accelerator are used at the time of ultraviolet crosslinking.

  Examples of the acrylic oligomer / monomer include polyester acrylate, polyether acrylate, epoxy acrylate, polyurethane acrylate, silicone acrylate, melamine acrylate, polybutadiene acrylate, and the like.

  In the reversible thermosensitive recording layer according to the present invention, a binder resin formed by crosslinking a polyol compound and an isocyanate compound, which is a preferable binder resin, will be described. Examples of the polyol compound include poly (meth) acryl polyol, polyester polyol, polycarbonate polyol, polyester polycarbonate polyol, polyether polyol, alkyd polyol, caprolactan polyol, and silicone polyol.

  Poly (meth) acrylic polyol is a copolymer of acrylic acid, methacrylic acid and esters thereof, which contains a hydroxyl group, and the copolymer component containing a hydroxyl group includes hydroxyethyl acrylate, methacrylic acid. Hydroxyethyl acid, hydroxypropyl acrylate, hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, allyl alcohol and the like are used. Examples of copolymer components other than acrylic acid, methacrylic acid and esters thereof include styrene, α-methylstyrene, vinyltoluene, acrylamide, methacrylamide and derivatives thereof, vinyl acetate, maleic anhydride and the like.

  Polyester polyol refers to a condensate of a polybasic acid and a polyhydric alcohol having a hydroxyl group. Polybasic acids used in these are phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid. , Aromatic polybasic acids such as trimesic acid, pyromellitic acid, naphthalenedicarboxylic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, 2-methylsuccinic acid, 2-methyladipic acid, 3-methyladipic acid, 3-methylpentanedioic acid, 2-methyloctanedioic acid, 3,7-dimethyldecanedioic acid, 3,8-dimethyldecanedioic acid, There are aliphatic polybasic acids such as dimer acid, and acid anhydrides obtained from these polybasic acids are also used.

  Polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, propanediol, neopentyl glycol, glycerin, trimethylolethane, trimethylolpropane, diglycerol, pentaerythritol, dipentaerythritol, di In addition to low molecular weight polyols such as acetone glycol and hexanetriol, high molecular weight polyols such as polyethylene glycol, polypropylene glycol and polybutylene glycol are also used. In addition to the polyester polyols obtained from these, hydroxycarboxylic acids, or condensates or ring-opening polymerizations thereof of cyclic lactones such as polybutyrolactone polyols, polycaprolactone polyols, and higher fatty acids in addition to the above polybasic acids and polyhydric alcohols. There are alkyd polyols obtained by condensation. The polyether polyol is a polymer having a main chain composed of an ether bond, and includes polyethylene glycol, polypropylene glycol, polyethylene glycol, and these branched esters.

  Examples of polyether polyols include ethylene oxide and / or propylene oxide adducts of polyhydric alcohols, polytetramethylene glycol, and the like. Examples of the silicone polyol include silicone oils having a siloxane bond in the molecule and a terminal hydroxyl group.

  In addition, fluorine-containing polyols such as hydroxyl-containing fluoroolefin, polyol hydroxyl-terminated polybutadiene, polyisoprene, hydrogenated polybutadiene, hydrogenated polyisoprene, polyurethane and the like can be used. Further, low molecular weight polyols such as diethylene glycol, triethylene glycol, glycerol, trimethylolpropane, pentaerythritol, 1,4-cyclohexadiol, 1,4-dihydroxybenzene, bisphenol A, bisphenol F, and other aliphatic, fatty A cyclic, aromatic polyhydric alcohol or polyhydric phenol or a condensate thereof is used as a reactive diluent.

  As the polyol compound according to the present invention, caprolactan polyol and polyester polyol are preferable from the comprehensive evaluation of additive dispersibility, coating property, adhesiveness, heat resistance and film strength. The polyol compound according to the present invention may be used alone or in combination with one or more other polyol compounds having different polyol parts or other partial structures or different molecular weights.

  A well-known thing can be used as an isocyanate compound concerning this invention. For example, aromatic aliphatic diisocyanates such as phenylene diisocyanate (PDI), toluene diisocyanate (TDI), naphthalene diisocyanate (NDI), 4,4'-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI), hydrogenated TDI, water Polyhydric tri- or higher functional polyhydric diisocyanates such as aliphatic or alicyclic diisocyanates such as XDI, hydrogenated MDI, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI) and their derivatives. In addition to isocyanate, various oligomers and polymers containing isocyanate may be mentioned. In the present invention, when xylylene diisocyanate or toluene isocyanate is used as the isocyanate compound, the color density is preferably improved. Further, when xylylene diisocyanate having a high background whiteness (such as Takenate D-110N manufactured by Mitsui Chemicals) is used. preferable.

  The isocyanate compound according to the present invention may be used alone or in combination with one or more isocyanates with respect to one or more polyol compounds. When a plurality of isocyanate compounds and polyol compounds are used, the combination may be arbitrary.

  The mixture of the polyol compound and the polyisocyanate compound may be used as it is when the mixture is liquid, but it can also be diluted with a non-reactive solvent with the polyisocyanate compound. As the solvent that can be used, a solvent that dissolves the polyol compound and the polyisocyanate compound and disperses and dissolves the dye precursor and the reversible developer is preferable. Specifically, the solvents exemplified in the method for incorporating the dye precursor and the reversible developer into the reversible thermosensitive recording layer coating liquid can be used. Among them, it is preferable to use an organic solvent that does not have active hydrogen that is reactive with the polyisocyanate compound. The crosslinking reaction between the polyol compound and the polyisocyanate compound may be performed at a reaction temperature of 30 to 160 ° C. and a reaction time of 1 minute to 120 hours. Needless to say, a long time is required when the reaction temperature is low, and a short time is required at a high temperature.

  The amount of binder resin used in the reversible thermosensitive recording layer according to the present invention is preferably such that the mass percentage of the binder resin relative to the total mass of the reversible thermosensitive recording layer is in the range of 35% to 65%. If it is larger than this range, the color density may decrease significantly. On the other hand, if it is smaller than this range, the heat resistance and mechanical strength of the reversible thermosensitive recording layer may be lowered, the layer may be deformed, and the color density may be lowered. The mass percentage of the binder resin in the reversible thermosensitive recording layer is more preferably 40% to 60%, and particularly preferably 45% to 55%.

  For a reversible thermosensitive recording layer coating liquid, a leveling agent, a dispersant, a hardener, a surfactant, a thickener, and an antifoaming agent are used for the purpose of improving coating properties or recording characteristics as necessary. , Decoloring modifier, antioxidant, anti-aging agent, filler, pigment, lubricant, antistatic agent, ultraviolet absorber, infrared absorber, colored dye / pigment, fluorescent whitening agent, heat fusible substance, preservative, etc. Can be contained in the reversible thermosensitive recording layer. Further, if necessary, a heat fusible substance can be added as a decoloring control agent for the reversible thermosensitive recording layer.

  When the reversible thermosensitive recording layer contains a curable resin, heating, ultraviolet irradiation, and electron beam irradiation are performed. Ultraviolet irradiation can be performed using a known ultraviolet irradiation device, and examples thereof include a light source, a lamp, a power source, a cooling device, and a conveying device. Examples of the light source include a mercury lamp, a metal halide lamp, a gallium lamp, a mercury xenon lamp, and a flash lamp. The wavelength of the light source can be appropriately selected according to the ultraviolet absorption wavelength of the photopolymerization initiator and the photopolymerization accelerator. The output and conveying speed of the ultraviolet irradiation are determined according to the irradiation energy necessary for crosslinking the ultraviolet curable resin.

  As the decoloring modifier added for the purpose of improving the decoloring property of the reversible thermosensitive recording layer, those having a melting point of 60 ° C. to 200 ° C. are preferred, and those having a melting point of 80 ° C. to 180 ° C. are particularly preferred. . Sensitizers used for general heat-sensitive recording paper can also be used. For example, waxes such as N-hydroxymethyl stearic acid amide, behenic acid amide, stearic acid amide, and palmitic acid amide, naphthol derivatives such as 2-benzyloxynaphthalene, and biphenyl derivatives such as p-benzylbiphenyl and 4-allyloxybiphenyl 1, 2-bis (3-methylphenoxy) ethane, 2,2′-bis (4-methoxyphenoxy) diethyl ether, polyether compounds such as bis (4-methoxyphenyl) ether, diphenyl carbonate, dibenzyl oxalate, Carbonic acid or oxalic acid diester derivatives such as bis (p-methylbenzyl) oxalate can be used in combination.

  Anti-aging agents added for the purpose of preventing aging of the reversible thermosensitive recording layer include amine compounds such as p, p'-diaminodiphenylmethane, aldol-α-naphthylamine, and N, N'-diphenyl-p-phenylenediamine. , Hydroquinone monobenzyl ether, phenol compounds such as 1,1-bis (p-hydroxyphenyl) cyclohexane, benzotriazole compounds, triazine compounds, benzophenone compounds, benzoates and the like. In addition, o-phenylenethiourea, zinc salt of 2-aminobenzimidazole, nickel dibutylthiocarbamate, zinc oxide, paraffin and the like can be mentioned. In addition, a polymer containing these monomers having an anti-aging structure as a component of polymerization, and a polymer main chain grafted with an anti-aging structure can also be used. Two or more types of anti-aging agents can be used in combination.

  Examples of pigments that can be added to the reversible thermosensitive recording layer include, for example, carbonates such as aluminum, zinc, calcium, magnesium, barium, and titanium, oxides, hydroxides, sulfates, etc., and zeolite, silica, Inorganic pigments containing clays such as kaolin, calcined kaolin and talc, starch, styrene resin, polyolefin resin, urea-formalin resin, melamine resin, acrylic resin, paraffin, natural wax, synthetic wax and the like can be used. Further, higher fatty acid metal salts such as zinc stearate and calcium stearate can be used as a lubricant.

  The film thickness of the reversible thermosensitive recording layer according to the present invention is determined by its composition and desired color density, and specifically, it is preferably in the range of 0.5 to 20 μm, more preferably 3 to 15 μm. .

  For the purpose of enhancing durability during repeated use, it is preferable to provide a protective layer on the reversible thermosensitive recording layer. The protective layer may be composed of a single layer or a plurality of layers of two layers or three or more layers. The protective layer preferably contains a curable resin such as a thermosetting resin, an electron beam curable resin, or an ultraviolet curable resin, and particularly preferably an electron beam curable resin or an ultraviolet curable resin. As the curable resin, resins exemplified as binder resins that can be used in the reversible thermosensitive recording layer can be used. Further, a pigment may be blended for the purpose of further improving durability or adjusting the glossiness, or a higher fatty acid metal salt or the like may be blended as a lubricant. As the pigment and the higher fatty acid metal salt, the compounds exemplified in the reversible thermosensitive recording layer can be used.

  The thickness of the protective layer is preferably in the range of 0.1 to 10 μm, more preferably 0.5 to 5 μm. When the film thickness exceeds 10 μm, not only the effect is saturated, but also the sensitivity of the reversible thermosensitive recording layer tends to decrease. When the film thickness is smaller than 0.1 μm, it is difficult to obtain the expected coating layer strength, and the coating layer is easily damaged.

  In the present invention, an intermediate layer is provided between the reversible thermosensitive recording layer and the protective layer for the purpose of improving image storability, etc., and an undercoat layer is provided between the support and the reversible thermosensitive recording layer for the purpose of improving color development sensitivity. A light reflecting layer or an air layer may be provided. The intermediate layer may contain an ultraviolet absorber. In the case where the reversible thermosensitive recording layer is provided only on one side of the support, a back coat layer may be provided on the other side. Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, and a salicylic acid phenyl ester ultraviolet absorber. The undercoat layer may contain hollow particles. These layers may be composed of a single layer or a plurality of layers of two or more layers. Moreover, it is preferable that these layers contain curable resins, such as a thermosetting resin, an electron beam curable resin, and an ultraviolet curable resin.

  In the present invention, a protective layer, an intermediate layer, an undercoat layer and the like provided on the support, if necessary, a leveling agent, a dispersant, a hardener, a surfactant, a thickener, a preservative, Add various additives such as fillers, coloring dyes, fluorescent brighteners, ultraviolet absorbers, infrared absorbers, antioxidants, antioxidants, pH adjusters, antifoaming agents, pigments, lubricants, antistatic agents, etc. be able to.

  The reversible thermosensitive recording material of the present invention may be provided with a printing recording layer such as printing such as offset printing or gravure printing; an ink jet recording layer, a thermal transfer image receiving layer, a sublimation thermal transfer image receiving layer. These print and print recording layers may be provided by being laminated with the reversible thermosensitive recording layer, or may be provided on a part of the same surface as the reversible thermosensitive recording layer. Further, it may be provided on a part of or the entire surface opposite to the surface on which the reversible thermosensitive recording layer is provided. An overprint varnish (OP varnish) layer mainly composed of a curable resin may be provided partially or entirely on the print recording layer.

  In the reversible thermosensitive recording material of the present invention, in the reversible thermosensitive recording layer, other layers, the surface provided with the reversible thermosensitive recording layer, the opposite surface, etc. are electrically, magnetically and optically information. May contain a recordable material. Further, the support may be a multilayer and an IC chip may be sandwiched between them. Further, an antistatic layer can be provided on one side or both sides for the purpose of antistatic. The reversible thermosensitive recording material of the present invention can be attached to another medium through an adhesive layer or the like, or using a heat-fusible resin as a support.

  When the IC chip is encapsulated between the layers of the reversible thermosensitive recording material, for example, it can be encapsulated between the layers of the plastic film or between the paper substrate and the plastic film. It is preferable from the viewpoint of print quality that sealing is performed between layers away from the reversible thermosensitive recording layer. When a non-contact IC chip is encapsulated, it can be encapsulated with an antenna. A cushion layer can be provided for the purpose of preventing the IC chip from being damaged by the pressure during encapsulation. The thickness of the cushion layer is preferably 10 μm or more because cushioning properties are insufficient if it is less than 10 μm. In addition, since a load is applied to the joint between the IC chip and the antenna, the area of the cushion layer is preferably large enough to cover the IC chip and the antenna joint. The cushion layer can be provided on one side or both sides. More preferably, cushion layers are provided on both sides. As the cushion layer, a thermoplastic resin is preferable. The foamed resin has better cushioning properties and can prevent the IC chip from being damaged.

  The method of laminating each layer in the present invention on a support to form a reversible thermosensitive recording material is not particularly limited, and can be formed by a conventional method. For example, air knife coater, blade coater, bar coater, curtain coater, gravure roll and transfer roll coater, roll coater, comma coater, smoothing coater, micro gravure coater, reverse roll coater, 4 roll roll coater, dip coater, Various coating machines such as a rod coater, a kiss coater, a gate roll coater, a squeeze coater, a slide coater, a die coater and other smearing apparatuses, a planographic plate, a relief plate, an intaglio plate, a flexo, a gravure, a screen, and a hot melt can be used. Furthermore, each layer can be held by ultraviolet irradiation or electron beam irradiation, aging by heating, or the like, in addition to a normal drying step. By these methods, it is possible to apply and print one layer at a time or multiple layers simultaneously.

  In the reversible thermosensitive recording material of the present invention, rapid cooling is required following heating to form a color-recorded recording image, and a slow cooling rate after heating is sufficient to erase the recorded image. For example, after heating by an appropriate method, a colored state can be developed by rapidly cooling by pressing a low-temperature metal block or the like. In addition, if the heating is performed for a very short time using a thermal head, laser light, or the like, the cooling is performed immediately after the heating is completed, so that the colored state can be maintained. On the other hand, when heated for a relatively long time with a suitable heat source (thermal head, laser light, heat roll, heat stamp, high-frequency heating, electric heater, radiant heat from a light source such as a tungsten lamp or halogen lamp, hot air, etc.) Since not only the layer but also the support and the like are heated, even if the heat source is removed, the cooling rate is slow, and the color is lost. Therefore, even when the same heating temperature and the same heat source are used, the coloring state and the decoloring state can be arbitrarily expressed by controlling the cooling rate.

  Examples of the laser used for heating include, but are not limited to, a semiconductor laser, a YAG laser, and a carbon dioxide gas laser. In order to efficiently perform heating with a semiconductor laser or a YAG laser, a reversible thermosensitive recording layer contains a photothermal conversion material having absorption in the near infrared region, or a photothermal conversion layer containing a photothermal conversion material is reversible. It is preferably provided directly adjacent to the thermal recording layer. Examples of photothermal conversion materials having absorption in the near infrared region include, for example, metal or metalloid layers such as platinum, titanium, silicon, chromium, nickel, germanium, and aluminum, immonium compounds, metal complex compounds, cyanine dyes, squarylium dyes, Photothermal conversion dyes such as naphthoquinone dyes, phthalocyanine compounds, and polymethine compounds can be used, and can be contained in the reversible thermosensitive recording layer in a dispersed state or in a molecular state. Preferable photothermal conversion dyes include phthalocyanine compounds and metal complex compounds in terms of photothermal conversion efficiency, solubility in solvents, dispersibility in resins, and light resistance to ultraviolet light, and phthalocyanine compounds are particularly preferable. When the photothermal conversion layer is provided in the vicinity of the reversible thermosensitive recording layer, a photothermal conversion layer made of a metal film such as a copper thin film or ITO can also be used.

  Examples of phthalocyanine compounds include naphthalocyanine compounds, metal-free phthalocyanine compounds, iron phthalocyanine compounds, copper phthalocyanine compounds, zinc phthalocyanine compounds, nickel phthalocyanine compounds, vanadyl phthalocyanine compounds, indium chloride phthalocyanine compounds, tin phthalocyanine compounds, and more preferably. Are vanadyl phthalocyanine compounds, zinc phthalocyanine compounds, and tin phthalocyanine compounds. The phthalocyanine compound used in the present invention may have a substituent on the aromatic ring for the purpose of adjusting the absorption wavelength, improving the solubility in a solvent, improving light resistance, and the like. Examples of the substituent include an alkyl ether group, an alkyl thioether group, an aryl ether group, an aryl thioether group, an amide group, an amino group, an alkyl ester group, an aryl ester group, a chlorine atom, and a fluorine atom. When there are two or more substituents on the aromatic ring, they may be the same or different, and the substituents may be bonded to form a ring.

  The amount of the photothermal conversion dye used is preferably set so that the absorbance at the oscillation wavelength of the light source used is 0.2 or more. If it is less than this amount, sufficient heat generation cannot be obtained, and the recording sensitivity is lowered. On the other hand, the photothermal conversion dye has some absorption in the visible region, and if the amount used is too large, the contrast is lowered. It is preferable to set an upper limit for the amount of photothermal conversion dye used so that an average transmittance of 400 nm to 700 nm can be secured by 60% or more. Two or more kinds of photothermal conversion dyes can be mixed and used.

  The photothermal conversion dye is preferably contained in at least one of the same layer or adjacent layers with respect to the layer containing the leuco dye and the reversible developer, and preferably contained in the same layer. It is more preferable for obtaining sensitivity.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this Example. In addition, the number of parts in an Example is a mass reference | standard.

Example 1
(A) Preparation of reversible thermosensitive recording layer coating solution As a dye precursor, 50 parts of 3- (p-toluidino) -2-methyl-8-dipropylaminofluorane, 3- (p-toluidino) -2-methyl 50 parts of -8-pyrrolidinofluorane, 300 parts of N-docosyl- [3- (p-hydroxyphenyl)] propionamide as a reversible developer, N- (1- (4-methyl) as an erasure accelerator Piperazinyl) -N′-octadecylurea 10 parts, docosylamine 0.3 part as a compound represented by the general formula (2), caprolactan polyol (manufactured by Daicel Industries, Ltd., trade name: PLACEL 303, active ingredient: 100) (Mass%) A mixture of 120 parts and 3000 parts of methyl ethyl ketone was dispersed with a glass bead for 5 hours with a paint shaker to obtain a dispersion. 450 parts of an isocyanate compound (trade name: Takenate D-110N, active ingredient: 75% by mass) manufactured by Mitsui Chemicals, Inc. was added to the dispersion thus obtained and mixed well, and the coating liquid for reversible thermosensitive recording layer was added. Was prepared.

(B) Coating of reversible thermosensitive recording layer coating solution The reversible thermosensitive recording layer coating solution obtained in (A) is dried on a white polyethylene terephthalate (PET) sheet having a thickness of 125 μm, and the film thickness after drying becomes 8 μm. After coating in this manner, the coating was dried at 95 ° C. for 1 minute, and further cured by heating at 50 ° C. for 48 hours to form a reversible thermosensitive recording layer.

(C) Preparation of intermediate layer coating solution 50 parts of 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -4- (2-hydroxyethyl) phenol] as a UV absorber, polyester polyol (DIC) Co., Ltd., trade name: Bernock 11-408, active ingredient 70 mass%) 100 parts and a mixture of 800 parts of methyl ethyl ketone were dispersed together with glass beads for 5 hours with a paint shaker to obtain a dispersion. 140 parts of an isocyanate compound (trade name: Takenate D-110N, active ingredient 75% by mass) and 50 parts of methyl ethyl ketone were added to the dispersion thus obtained and mixed well to prepare an intermediate layer coating solution. Prepared.

(D) Coating of intermediate layer coating liquid On the reversible thermosensitive recording layer coated surface of the coated sheet prepared in (B), the film thickness after drying the intermediate layer coating liquid obtained in (C) is 1 μm. After coating at 95 ° C. for 1 minute, the coating was further cured by heating at 50 ° C. for 48 hours to provide an intermediate layer.

(E) Preparation of coating solution for protective layer Urethane acrylate UV curable resin (manufactured by DIC Corporation, trade name: Unidic 17-813, active ingredient: 80% by mass) 12.5 parts, wet method silica (Fuji Silysia Chemical) (Product name: Silicia 350) 2.0 parts and butyl acetate 10 parts were mixed. The liquid mixture thus obtained was treated with a bead mill to prepare a protective layer coating solution.

(F) Application of protective layer coating solution On the intermediate layer coating surface of the coating sheet prepared in (D), apply the protective layer coating solution obtained in (E) so that the film thickness after drying is 2 μm. And dried at 95 ° C. for 1 minute, and then cured by passing through a UV lamp with an irradiation energy of 120 W / cm at a conveyance speed of 10 m / min to provide a protective layer, whereby the reversible thermosensitive recording material of Example 1 was obtained. It was.

(Example 2)
A reversible thermosensitive recording material of Example 2 was obtained in the same manner as in Example 1 except that the number of parts of docosylamine was 0.03 parts in Example 1 (A).

(Example 3)
A reversible thermosensitive recording material of Example 3 was obtained in the same manner as in Example 1 except that the number of parts of docosylamine was 3 in Example 1 (A).

Example 4
A reversible thermosensitive recording material of Example 4 was obtained in the same manner as in Example 1 except that the number of parts of docosylamine was 0.015 part in Example 1 (A).

(Example 5)
A reversible thermosensitive recording material of Example 5 was obtained in the same manner as in Example 1 except that the number of parts of docosylamine was 6 in Example 1 (A).

(Example 6)
Instead of using 300 parts of N-docosyl- [3- (p-hydroxyphenyl)] propionamide as the reversible developer in Example 1 (A), N-tetracosyl- [3- (p-hydroxyphenyl) The reversible thermosensitive recording material of Example 6 was obtained in the same manner as in Example 1 except that 300 parts of propionamide was used.

(Example 7)
Instead of using 300 parts of N-docosyl- [3- (p-hydroxyphenyl)] propionamide as the reversible developer in Example 1 (A), N-hexacosyl- [3- (p-hydroxyphenyl) The reversible thermosensitive recording material of Example 7 was obtained in the same manner as in Example 1 except that 300 parts of propionamide was used.

(Example 8)
Instead of using 300 parts of N-docosyl- [3- (p-hydroxyphenyl)] propionamide as the reversible developer in Example 1 (A), N-triacontyl- [3- (p-hydroxyphenyl) A reversible thermosensitive recording material of Example 8 was obtained in the same manner as Example 1 except that 300 parts of propionamide was used.

Example 9
A reversible thermosensitive recording material of Example 9 was obtained in the same manner as in Example 1 except that 0.3 part of tetracosylamine was used instead of 0.3 part of docosylamine in Example 1 (A). .

(Example 10)
A reversible thermosensitive recording material of Example 10 was obtained in the same manner as in Example 1 except that 0.3 part of hexacosylamine was used instead of 0.3 part of docosylamine in Example 1 (A). .

(Example 11)
A reversible thermosensitive recording material of Example 11 was obtained in the same manner as in Example 1 except that 0.3 part of triacontylamine was used instead of 0.3 part of docosylamine in Example 1 (A). .

(Example 12)
A reversible thermosensitive recording material of Example 12 was obtained in the same manner as in Example 1 except that 0.3 part of docosylmethylamine was used instead of 0.3 part of docosylamine in Example 1 (A). It was.

(Example 13)
A reversible thermosensitive recording material of Example 13 was obtained in the same manner as in Example 1 except that 0.3 part of docosyldimethylamine was used instead of 0.3 part of docosylamine in Example 1 (A). It was.

(Example 14)
In Example 1 (A), instead of using 0.3 part of docosylamine, 0.3 part of tetracosylamine was used, and N-docosyl- [3- (p-hydroxyphenyl)] propionamide was used as a reversible developer. A reversible thermosensitive recording material of Example 14 was obtained in the same manner as in Example 1 except that 300 parts of N-tetracosyl- [3- (p-hydroxyphenyl)] propionamide was used instead of 300 parts. .

(Example 15)
Instead of using 0.3 part of docosylamine in Example 1 (A), 0.3 part of triacontylamine was used, and N-docosyl- [3- (p-hydroxyphenyl)] propionamide as a reversible developer A reversible thermosensitive recording material of Example 15 was obtained in the same manner as in Example 1 except that 300 parts of N-triacontyl- [3- (p-hydroxyphenyl)] propionamide was used instead of 300 parts. .

(Comparative Example 1)
A reversible thermosensitive recording material of Comparative Example 1 was obtained in the same manner as in Example 1 except that 0.3 part of octadecylamine was used instead of 0.3 part of docosylamine in Example 1 (A).

(Comparative Example 2)
In Example 1 (A), instead of using 300 parts of N-docosyl- [3- (p-hydroxyphenyl)] propionamide as a reversible developer, N-octadecyl- [3- (p-hydroxyphenyl) A reversible thermosensitive recording material of Comparative Example 2 was obtained in the same manner as in Example 1 except that 300 parts of propionamide was used.

(Comparative Example 3)
In Example 1 (A), instead of using 0.3 part of docosylamine, 0.3 part of octadecylamine was used, and N-docosyl- [3- (p-hydroxyphenyl)] propionamide 300 was used as the reversible developer. A reversible thermosensitive recording material of Comparative Example 3 was obtained in the same manner as in Example 1 except that 300 parts of N-octadecyl- [3- (p-hydroxyphenyl)] propionamide was used instead of using parts.

(Comparative Example 4)
Instead of using 0.3 part of docosylamine in Example 1 (A), 0.3 part of triacontylamine was used, and N-docosyl- [3- (p-hydroxyphenyl)] propionamide as a reversible developer The reversible thermosensitive recording material of Comparative Example 4 was prepared in the same manner as in Example 1 except that 300 parts of N-tetratriacontyl- [3- (p-hydroxyphenyl)] acetamide was used instead of 300 parts. Obtained.

(Comparative Example 5)
Instead of using 0.3 part of docosylamine in Example 1 (A), 0.3 part of tetratriacontylamine was used, and N-docosyl- [3- (p-hydroxyphenyl)] propion as a reversible developer A reversible thermosensitive recording material of Comparative Example 5 was obtained in the same manner as in Example 1 except that 300 parts of N-triacontyl- [3- (p-hydroxyphenyl)] acetamide was used instead of 300 parts of amide. .

(Comparative Example 6)
Instead of using 0.3 part of docosylamine in Example 1 (A), 0.3 part of tetratriacontylamine was used, and N-docosyl- [3- (p-hydroxyphenyl)] propion as a reversible developer Reversible thermosensitive recording material of Comparative Example 6 in the same manner as in Example 1 except that 300 parts of N-tetratriacontyl- [3- (p-hydroxyphenyl)] acetamide was used instead of 300 parts of amide. Got.

(Comparative Example 7)
A reversible thermosensitive recording material of Comparative Example 7 was obtained in the same manner as in Example 1 except that 0.3 part of diisopropylamine was used instead of 0.3 part of docosylamine in Example 1 (A).

(Comparative Example 8)
A reversible thermosensitive recording material of Comparative Example 8 was obtained in the same manner as in Example 1 except that 0.3 part of cyclohexylamine was used instead of 0.3 part of docosylamine in Example 1 (A).

(Comparative Example 9)
A reversible thermosensitive recording material of Comparative Example 9 was obtained in the same manner as in Example 1 except that 0.3 part of dibenzylamine was used instead of 0.3 part of docosylamine in Example 1 (A). .

(Comparative Example 10)
A reversible thermosensitive recording material of Comparative Example 10 was obtained in the same manner as in Example 1 except that docosylamine was not added in Example 1 (A).

(Test 1) Color developability For the evaluation method of color developability, the reversible thermosensitive recording materials obtained in Examples 1 to 15 and Comparative Examples 1 to 10 were used as thermal color development test devices (TH-PMG manufactured by Okura Electric Co., Ltd.). Printing was performed with a printing head of TDK-BHC4215SS) under a printing energy of 0.36 mj / dot. The color density was measured using a Macbeth densitometer RD-19I. If the color density is 1.0 or more, there is no problem in actual use. The color density was evaluated according to the following criteria.

Color density ◎: 1.2 or more ○: 1.0 or more and less than 1.2 ×: Less than 1.0

(Test 2) Decoloring property About the decoloring property evaluation method, the reversible thermosensitive recording material obtained in Test 1 was put into a constant temperature dryer set at 80 ° C. and erased. Using the Macbeth densitometer RD-19I, the density of the background and the image area after erasure was measured, and the remaining density (difference between the image area density after erasure and the background density) was calculated. If the unerased density is 0.02 or less, there is no problem in actual use. The disappearance density was evaluated according to the following criteria.

Time it takes for the remaining concentration to disappear to 0.02 or less ◎: Less than 5 minutes ○: 5 minutes or more and less than 15 minutes △: 15 minutes or more and less than 30 minutes ×: 30 minutes or more

(Test 3) Heat-resistant storage stability test The image obtained in Test 1 above was stored in a thermostatic dryer set at 50 ° C. for 24 hours, and then the density of the colored portion was measured in the same manner as Test 1, and the following formula (1 ) To calculate the image remaining rate. If the image remaining rate is 70% or more, it is at a level where there is no problem in actual use. The heat resistant storage stability of the image area was evaluated according to the following criteria.

Image residual ratio ◎: 80% or more ○: 70% or more and less than 80% △: 60% or more and less than 70% ×: Less than 60%

Formula (1) A = (C / B) × 100
A: Image remaining rate (%)
B: Color density before test
C: Color density after test

The results of Test 1 to Test 3 are shown in Table 1.

  As apparent from the above results, the carbon number of the linear alkyl group of the reversible developer in the reversible thermosensitive recording layer is 20 to 32, and the linear alkyl group in the reversible thermosensitive recording layer. By adding an amine compound having 20 to 32 carbon atoms, a stable image can be maintained over time even in a high temperature environment, and a reversible thermosensitive recording material excellent in color development and decoloring properties can be provided.

Claims (1)

Contains a normally colorless or light-colored dye precursor on a support and a reversible developer that forms a relatively colored state and a decolored state due to differences in heating temperature and / or cooling rate after heating. In the reversible thermosensitive recording material provided with the reversible thermosensitive recording layer, the reversible thermosensitive recording layer contains a reversible developer represented by the following general formula (1), and is represented by the following general formula (2). A reversible thermosensitive recording material containing the linear amine compound represented.

In the general formula (1), R ¹ represents a linear hydrocarbon group having 20 to 32 carbon atoms, and X represents an amide group or a urea group.

In the general formula (2), R ² represents a linear hydrocarbon group having 20 to 32 carbon atoms, and R ³ and R ⁴ represent a hydrogen atom or a methyl group.