JPWO2005121072A1 - Hydroxyphenylhydroxyalkylamide compound, reversible thermosensitive composition, reversible thermosensitive recording material, and color development process - Google Patents

Abstract

A novel hydroxyphenylhydroxyalkylamide compound, and reversible color development stability and erasability, color development sensitivity, balance between color development temperature and color erase temperature, and storage stability against heat in color development state Providing a heat-sensitive composition, a reversible heat-sensitive recording material, and a color-decoloring process. A reversible thermosensitive composition and reversible thermosensitive recording material comprising a hydroxyphenylhydroxyalkylamide compound represented by the following general formula (I), the electron accepting compound and an electron donating color developing compound. This recording material can be colored or decolored by temperature control. (N is an integer of 1 to 3, and A is a linear hydroxyalkyl group in which a hydroxyl group is bonded to a carbon atom other than the terminal carbon.)

Description

  The present invention relates to a novel hydroxyphenylhydroxyalkylamide compound that can be used for thermal recording (color development / decoloration / decoloration), a reversible thermosensitive recording material using the same, and a color development process. It is.

  It is well known that a colorless or light-colored electron-donating color-forming compound reacts with an electron-accepting compound to cause irreversible color development. Recording paper that applies this principle includes pressure-sensitive paper and heat-sensitive paper. The pressure-sensitive paper includes a base paper coated with a leuco dye solution, which is an electron-donating color-forming compound, in a microcapsule and coated with a binder. , Using a base paper coated with an electron-accepting compound such as bisphenol A together with a binder, etc., destroying the microcapsules by external pressure, causing the electron-donating compound and the electron-accepting compound to melt and react, There are things that make use of coloring.

  Also known as thermal paper is a paper coated with fine powders such as leuco dye, bisphenol A, sensitizer and storage stabilizer together with a binder. This thermal paper utilizes coloration by heat supplied from the head of a thermal printer (see, for example, Patent Document 1).

  2. Description of the Related Art Conventionally, from the viewpoint of reducing environmental burdens or from the viewpoint of convenience, technical development has been vigorously carried out to perform color development and decolorization thermally and reversibly. For example, Patent Document 2 discloses a thermochromic composition using a leuco dye that is an electron-donating color-forming compound and phenol that is an electron-accepting compound.

  In addition, (a) an electron-donating color-forming compound, (b) an electron-accepting compound, and (c) a reaction temperature regulator, the color is selected with the component (a), and the color density with the component (b) Patent Documents 3 to 5 and the like describe reversible thermochromic compositions and compositions containing the compositions in microcapsules, in which the coloration temperature is determined by component (c). In Patent Documents 6 to 9, a recording layer comprising an electron-accepting color-forming compound, an electron-accepting compound such as gallic acid or phloroglucinol, and a binder such as cellulose acetate is provided on a substrate, and heat is applied to the image. A reversible recording material is disclosed that can be formed and erased with water or water vapor.

  However, since these recording materials erase images with water or water vapor, the formed images are easily affected by moisture and moisture, and there is a problem in image stability.

  In Patent Document 10, a compatible solution composed of a compound having a lactone ring as an electron-donating color-forming compound and an alkylphenol liquid at room temperature as an electron-accepting compound is enclosed in glass or microcapsules without using a binder. And a material that reversibly develops decoloring and color development by heating and cooling. The material described in this patent document is colorless and transparent when heated, and loses fluidity when cooled and develops color. However, since there is no hysteresis, recording cannot be held, and there is room for improvement as a recording material.

  Further, proposals of reversible thermosensitive recording materials comprising a leuco dye, an amphoteric compound having a functional group that reacts with the dye to develop or decolor each and a polymer binder are disclosed in Patent Documents 11 to 21, etc. ing. More specifically, Patent Document 11 discloses a thermosensitive recording material comprising a complex of gallic acid and 3-methoxypropylamine, which is an amphoteric compound having a functional group related to color development or decoloration, crystal violet lactone, and polyvinyl alcohol binder. Is disclosed. Patent Document 16 discloses a heat-sensitive recording material comprising a compound having at least one of a phenolic hydroxyl group or a carboxyl group and having an amino group as a functional group, crystal violet lactone, and a methacrylic resin binder.

  However, these reversible thermosensitive recording materials are difficult to control the temperature of color development and color erasing because the color development and color erasing operations occur competitively, and have poor image contrast. There was a problem that the material was deteriorated and the number of repeated use was reduced.

  Patent Document 22 uses an electron-accepting compound selected from an electron-donating color-forming compound, a phosphonic acid compound having a long-chain aliphatic hydrocarbon group, an aliphatic carboxylic acid compound, and a phenol compound. There has been proposed a recording material in which color development and decoloring can be easily performed by controlling heating and cooling in combination with a color developing compound and can be stably maintained at room temperature. When this composition is heated to a color development temperature range, both compounds melt and react to cause the color-forming compound to open and color, and by rapidly cooling it, the color development state can be maintained even at room temperature. Yes. When the colored composition is heated to a decoloring temperature range lower than the coloring temperature range, the long-chain alkyl group of the electron-accepting compound aggregates, and the electron-accepting compound becomes a single crystal, which It is presumed that it will be separated and as a result decolored. That is, in the relationship between the electron-donating color-forming compound and the electron-accepting compound, the colored state is maintained by solidifying the two compounds while they are reacted, and the electron-accepting compound is thermally It is said that it separates and crystallizes under conditions to form a single crystal and maintain a decolored state. However, in these recording materials, the phenolic compounds described in the examples are at practical levels in terms of color development / decoloration density and color stability, except for the part where the decolorization property is not good. As described in No. 1, there is a problem that the decoloring speed takes time.

On the other hand, Patent Document 23 proposes a recording material in which printing and erasing can be repeated in the same manner. By using a special phenol compound as an electron-accepting compound, the erasing speed is improved and heating is performed within 1 second. Shows that the printed image can be almost erased. However, as described in Non-Patent Document 2, the storage stability of this material is not necessarily sufficient at a temperature exceeding 30 ° C. Therefore, it is desired to further improve the storage stability in practical use. In addition, Non-Patent Document 1 discloses, as means for solving these problems (storage stability, erasing speed, or color developing color density), the hydrogen bond in the molecule and the acidity of the electron-accepting compound. Paying attention, by introducing a functional group having hydrogen bonding performance into the long-chain alkyl group of the electron-accepting compound and introducing a methylene chain as a spacer, hydrogen bonding properties are effectively expressed and storage stability is good. The results of material studies have been reported. By using this electron-accepting compound, the storage stability is improved, but the introduction of the functional group and the spacer group raises the melting point by about 20 to 50 ° C. compared to before the introduction. This melting point is correlated with the color development temperature, that is, the color development sensitivity, and as a result, the color development sensitivity tends to decrease. Lowering the color development sensitivity means that the color density is lowered in a thermal head such as a FAX or a thermal printer that is currently used for general purposes, and it is difficult to use it as it is in existing hardware. As a result, problems such as the use of dedicated hardware or the need to use other additives such as a sensitizer to increase sensitivity remain.
Japanese Patent Publication No. 4-7600 US Pat. No. 3,560,229 Japanese Patent Publication No. 51-44706 Japanese Patent Publication No. 51-44707 Japanese Patent Publication No. 51-44708 JP 58-191190 A JP-A-60-257289 Japanese Patent Publication No. 4-30355 Japanese Patent Publication No. 4-30916 JP-A-63-315287 JP-A-5-254244 Japanese Patent Laid-Open No. 5-262632 JP-A-6-48028 JP-A-2-188293 JP-A-2-188294 International Patent Publication No. WO90 / 11898 pamphlet JP-A-4-46986 JP-A-4-303680 JP-A-4-50289 JP-A-4-50290 Japanese Patent Application Laid-Open No. 5-177931 Japanese Patent No. 2981558 Japanese Patent No. 3380277 Ricoh Technical Report 25, 6 (1999) Proceedings of the 3rd meeting of the Electrophotographic Society 1997, 10 (1997)

  In view of the above-mentioned problems, the object of the present invention is to maintain the stability of color development and erasability, and without reducing the color development sensitivity or high-speed erasability, and having good storage stability against heat in the color development state, reversible thermosensitive An object is to provide an electron-accepting compound that can also be applied to a recording material, and to provide a reversible thermosensitive recording material and a color-decoloring process using the same.

（ここで、ｎは、１〜３の整数であり、Ａは、末端炭素以外の炭素原子に水酸基が結合した、直鎖のヒドロキシアルキル基である。）The hydroxyphenylhydroxyalkylamide compound according to the present invention is represented by the following general formula (I).

(Here, n is an integer of 1 to 3, and A is a linear hydroxyalkyl group in which a hydroxyl group is bonded to a carbon atom other than the terminal carbon.)

  Moreover, the reversible thermosensitive composition by this invention is characterized by including the hydroxyphenyl hydroxyalkylamide compound represented by the said general formula (I), and an electron-donating color-forming compound.

  The reversible thermosensitive recording material according to the present invention comprises a recording element comprising a hydroxyphenylhydroxyalkylamide compound represented by the general formula (I) and an electron donating color developing compound. To do.

  The color development / decolorization process according to the present invention comprises a reversible thermosensitive recording material comprising a recording element comprising a hydroxyphenylhydroxyalkylamide compound represented by the general formula (I) and an electron donating color developing compound. , The electron accepting compound and the electron donating color-forming compound are both heated to a color development temperature at which they are melt-reacted, and then rapidly cooled and then kept in a colored state stably. Further, it is characterized in that it is decolored by heating to a decoloring temperature range where a reverse reaction to the melting reaction occurs.

  According to the present invention, an electron acceptor capable of realizing a reversible thermosensitive recording material having excellent color stability and erasability, color development sensitivity, balance between color development temperature and color erase temperature, and storage stability against heat in a color development state. A hydroxyphenyl hydroxyalkylamide compound is provided which is a functional compound. This hydroxyphenylhydroxyalkylamide compound is suitable for a reversible thermosensitive recording material, and can also realize a reversible thermosensitive composition, a reversible thermosensitive recording material, and a color development / decoloring process having the above-mentioned characteristics. .

The conceptual diagram of color development or decoloring in the reversible thermosensitive composition of this invention. The IR spectrum of N- (4-hydroxyphenyl) -12-hydroxy stearamide synthesized in Synthesis Example 1. 2 is a DSC chart of N- (4-hydroxyphenyl) -12-hydroxystearamide synthesized in Synthesis Example 1. The IR spectrum of N- (3-hydroxyphenyl) -12-hydroxy stearamide synthesized in Synthesis Example 2. 6 is a DSC chart of N- (3-hydroxyphenyl) -12-hydroxystearamide synthesized in Synthesis Example 2. The IR spectrum of N- (4-hydroxyphenyl) -12-hydroxypentadecanamide synthesized in Synthesis Example 3. 9 is a DSC chart of N- (4-hydroxyphenyl) -12-hydroxypentadecanamide synthesized in Synthesis Example 3.

1. Hydroxyphenyl hydroxyalkylamide compound The present inventor has developed a functional group capable of forming a hydrogen bond with an alkyl group of an amide group-containing phenol compound having a long-chain alkyl group, specifically, a hydroxyl group at a terminal carbon in the alkyl chain. By substituting with hydrogen atoms that are not bonded to develop hydrogen bonding ability, color development is not impaired when used as a reversible thermosensitive material without greatly changing the melting point of the hydroxyphenylhydroxyalkylamide compound. It has been found that stability and color development sensitivity can be improved unexpectedly.

ここでｎは、１〜３の整数であり、Ａは、末端炭素以外の炭素原子に水酸基が結合した、直鎖のヒドロキシアルキル基である。The hydroxyphenylhydroxyalkylamide compound according to the present invention is represented by the following general formula (I).

Here, n is an integer of 1 to 3, and A is a linear hydroxyalkyl group in which a hydroxyl group is bonded to a carbon atom other than the terminal carbon.

  This hydroxyphenylhydroxyalkylamide compound can be used as an electron-accepting compound that can be used in a heat-sensitive recording material in combination with an electron-donating color-forming compound. For this reason, the hydroxyphenylhydroxyalkylamide compound according to the present invention may be hereinafter referred to as an electron accepting compound.

ここでｍおよびｌは、それぞれ独立に０以上の整数であり、ｋは１以上の整数を表す。Specific examples of the structural formula of A include the following general formula (II).

Here, m and l are each independently an integer of 0 or more, and k represents an integer of 1 or more.

  When m + 1 increases, alkyl chains tend to aggregate when used in a reversible thermosensitive recording material, and the erasability tends to improve. Therefore, m + 1 is preferably 6 or more, more preferably 11 or more. More preferred. On the other hand, if m + 1 is decreased, the melting point of the compound is lowered, and the color development sensitivity tends to be improved. Therefore, m + 1 is preferably 22 or less.

  Further, k is preferably 1 or 2 from the viewpoint of image erasability and color stability when used in a reversible thermosensitive recording material.

Specific examples of such compounds include the following compounds.

  The compound represented by the general formula (I) can be synthesized by using a generally known amide synthesis method. More specifically, an aminophenol having 1 to 3 hydroxyl groups and a hydroxyalkylcarboxylic acid having a hydroxyl group bonded to carbon other than the terminal carbon are heated and refluxed in the presence of a solvent and / or a catalyst as necessary. Can be manufactured. One of the characteristics of these electron-accepting compounds is that they can be synthesized using general-purpose chemicals.

  Whether or not the target compound has been obtained can be confirmed by differential scanning calorimetry (hereinafter sometimes referred to as DSC) and infrared absorption spectrum (hereinafter sometimes referred to as IR).

2. Reversible thermosensitive composition The reversible thermosensitive composition according to the present invention comprises the hydroxyphenylhydroxyalkylamide compound of the general formula (I) and an electron donating color-forming compound. This composition reversibly changes color by temperature control. This composition can also be called a reversible thermochromic composition.

  FIG. 1 is a conceptual diagram of color development or color erasing by a combination (that is, a mixture) of an electron accepting compound and an electron donating color developing compound in the reversible thermosensitive composition according to the present invention.

  In FIG. 1, the decolored state A is a state in which both compounds are not reacted in the mixture. When this mixture is heated and passes through B and C and reaches D (the temperature in the vicinity of D or higher is called the color development temperature range, the temperature in the vicinity of the melting point of the electron-accepting compound), the electron-accepting compound and the electron donating The color developing compound reacts in a molten mixed state and develops color. When this is rapidly cooled, the electron-accepting compound and the electron-donating color-forming compound are solidified in a reacted state, so that D to E, which are different from the route from the decolored state A to the colored state D, are changed. As a result, the colored state is maintained at a low temperature, for example, room temperature. Next, when the E state is heated to a temperature between B and C (the temperature range in the vicinity thereof is referred to as a decoloring temperature range), aggregation of the alkyl chain occurs in the electron accepting compound alone, and the electron donating color developing compound The connection with is broken, and the color disappears. Even if this is cooled to room temperature, the colored state E is not achieved but the decolored state A is maintained. As described above, when the electron-accepting compound of the present invention is used, it can be maintained in a state of color development or color erasing at a low temperature.

  The electron-accepting compound that can be used in the present invention is limited to those described in the general formula (I), but the electron-donating color-forming compound to be combined therewith is not particularly limited. An example of an electron-donating color-forming compound is a colorless or light-colored dye used as a pressure-sensitive and heat-sensitive dye, and is generally called a leuco dye, such as triphenylmethanephthalide dye, fluorane dye, Examples thereof include indolylphthalide dyes, spiropyran dyes, rhodamine lactam dyes, triphenylmethane dyes, azaphthalide dyes, azomethine dyes, and phenothiazine dyes. Specific examples of the electron donating color-forming compound that can be used in the present invention are listed below, but the invention is not limited thereto.

3-diethylamino-6-methyl-7-phenylaminofluorane, 3-diethylamino-7- (2-chlorophenyl) aminofluorane, 3-diethylamino-7- (2-bromophenyl) aminofluorane, 3-diethylamino- 6-methyl-7-chlorofluorane, 3-diethylamino-6-methyl-7- (3-trifluoromethylphenyl) aminofluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-bromofluor Oran, 3-diethylamino-7-piperidinofluorane, 3-diethylamino-7- (N-ethyl-N-phenyl) aminofluorane, 3-diethylamino-7,8-benzofluorane, 3-diethylamino-6 -Chloro-7- (2,3-dicyclohexylphenyl) aminofluorane 3-diethylamino-6-chloro-7-phenylaminofluorane, 3-diethylamino-6-methyl-7- (2,4-dimethylphenyl) aminofluorane, 3-diethylamino-6-chloro-7- (3- Trifluoromethylphenyl) aminofluorane, 3-diethylamino-6-methyl-7-phenylaminofluorane, 3-diethylamino-7- (3-trifluoromethylphenyl) aminofluorane, 3-dipropylamino-7- Chlorofluorane, 3-diethylamino-6-methyl-7- (3-trichloromethylphenyl) aminofluorane, 3-diethylamino-7- (2-methoxycarbonylphenyl) aminofluorane, 3-diallylamino-7,8 -Benzofluorane, 3-diethylamino-5-chloro-7- (N-α -Phenylethyl) aminofluorane, 3-diethylamino-5-methyl-7- (N-phenylethyl) aminofluorane, 3-diethylamino-5-methyl-7-dibenzylaminofluorane, 3-diethylamino-7- Medoxyfluorane, 3-diethylamino-6-diethylaminofluorane, 3-diethylamino-7- (p-toluidino) fluorane, 3-diethylamino-5-chloro-7- {N-benzyl-N- (trifluoromethylphenyl) )} Aminofluorane, 3-dibutylamino-7- (2-chlorophenyl) aminofluorane, 3-diethylamino-7-acetaminofluorane, 3-dibutylamino-6-chloro-7-ethoxyethylaminofluorane, 3-Dibutylamino-7- (2-fluorophenyl) aminophen Oran, 3-dibutylamino-7,8-benzofluorane, 3-cyclohexylamino-6-chlorofluorane, 3-dibutylamino-6-methyl-7-phenylaminofluorane, 3-dimethylamino-5,7 -Dimethylfluorane, 3-cyclohexylamino-6-chlorofluorane, 3-cyclohexylamino-6-bromofluorane, 3-cyclohexylamino-6-chloro-7- (2-chlorophenyl) aminofluorane, 3- ( N-methyl-N-cyclohexyl) amino-7,8-benzofluorane, 3- (N-ethyl-Nn-octyl) amino-7,8-benzofluorane, 3- (N-ethyl-N- i-amyl) amino-7,8-benzofluorane, 3- (N-ethyl-Ni-amyl) amino-7-chlorofluorane, -(N-methyl-N-cyclohexyl) amino-6-methyl-7- (3-trifluoromethylphenyl) aminofluorane, 3- (N-methyl-Ni-propyl) amino-6-methyl-7 -Phenylaminofluorane, 3- (N-benzyl-N-cyclohexyl) amino-5,6-benzo-7- (4-bromonaphthyl) aminofluorane, 3- (Ni-butyl-N-methyl) Amino-6-methyl-7-phenylaminofluorane, 3- (N-ethyl-Ni-amyl) amino-6-methyl-7-phenylaminofluorane, 3- (N-ethyl-N-hexyl) Amino-7-phenylaminofluorane, 3- (Nn-amyl-N-methyl) amino-6-methyl-7-phenylaminofluorane, 3- (N-methyl-N-cyclohexyl) Amino-6-methyl-7-phenylaminofluorane, 3- (N-methyl-Nn-propyl) amino-6-methyl-7-phenylaminofluorane, 3- (Nn-propyl-N- i-propyl) amino-6-methyl-7-phenylaminofluorane, 3- (N-ethyl-N-Sec-butyl) amino-6-methyl-7-phenylaminofluorane, 3- (N-ethyl- N-n-amyl) amino-6-methyl-7-phenylmethylfluorane, 3-di-n-octylamino-7- (4-chlorophenyl) aminofluorane, 3-n-octylamino-7- (4 -Chlorophenyl) aminofluorane, 3- (Nn-butyl-Nn-amyl) amino-7- (4-acetyl-phenyl) aminofluorane, 3-n-octylamino-7- (4 Chlorophenyl) aminofluorane, 3-n-cetylamino-7- (4-chlorophenyl) aminofluorane, 3-pyrrolidino-6-methyl-7-phenylaminofluorane, 3-pyrrolidino-7- {bis (4-chlorophenyl) ) Methyl} aminofluorane, 3-morpholino-7- {N-propyl-N- (4-trifluoromethylphenyl)} aminofluorane, 3-pyrrolidino-6-chloro-7-phenylaminofluorane, 3- Pyrrolidino-6-methyl-7- (3-trifluoromethylphenyl) aminofluorane, 3-morpholino-7- {N-propyl-N- (3-trifluorophenyl)} aminofluorane, 3- (N- Ethyl-N-ethoxyethyl) amino-7,8-benzofluorane, 3- {N-ethyl-N- (2-ethoxy) Ropyl)} amino-6-methyl-7-phenylaminofluorane, 3- (N-ethyl-N-tetrahydrofurfuryl) amino-6-methyl-7-phenylaminofluorane, 3- (N-methyl-N -Phenyl) amino-7-aminofluorane, 3- (N-methyl-N-phenyl) amino-7-N-methylaminofluorane, 3- (N-methyl-N-phenyl) amino-7-dimethylamino Fluorane, 3- (N-methyl-N-phenyl) amino-7-dipropylaminofluorane, 3- (N-ethyl-N-phenyl) -6-methyl-7- {N-ethyl-N- ( 4-methylphenyl)} aminofluorane, 3- (N-ethyl-N-phenyl) amino-7-dimethylaminofluorane, 3- (N-ethyl-N-phenyl) amino-7-dipropyl Aminofluorane, 3- (N-ethyl-N-phenyl) amino-7-aminofluorane, 3- (N-phenyl-N-propyl) amino-7-aminofluorane, 3- (N-ethyl-N -Phenyl) amino-7-N-methylaminofluorane, 3- (N-propyl-N-phenyl) amino-7-N-methylaminofluorane, 3- {N-methyl-N- (4-methylphenyl) )} Amino-5-methoxy-7-dibenzylaminofluorane, 3- {N-methyl-N- (4-methylphenyl)} amino-6-t-butyl-7- (4-methylphenyl) aminofluor Oran, 3- {N-methyl-N- (4-methylphenyl)} amino-7- (2-methoxybenzoyl) aminofluorane, 3- {N-methyl-N- (4-methylphenyl)} amino- 7-a Tylaminofluorane, 3- {N-methyl-N- (4-methylphenyl)} amino-7-dibenzylaminofluorane, 3- {N-methyl-N- (4-methylphenyl)} amino-7 -Diethylaminofluorane, 3- {N-methyl-N- (4-methylphenyl)} amino-7-ethylaminofluorane, 3- {N-methyl-N- (4-methylphenyl)} amino-7- Aminofluorane, 3- (N-methyl-N-phenyl) amino-6-methyl-7-phenylaminofluorane, 3- (3-trifluoromethylphenyl) amino-6-diethylaminofluorane, 3- {N -Ethyl-N- (4-methylphenyl)} amino-6-methyl-7-phenylaminofluorane, 3- {N-ethyl-N- (4-methylphenyl)} amino-7- ( -Methyl-N-phenyl) aminofluorane, 3- {N-ethyl-N- (4-methylphenyl)} amino-7- (α-phenylethyl) aminofluorane, 3- {N-ethyl-N- (4-Methylphenyl)} amino-7-aminofluorane, 3- {N-ethyl-N- (4-methylphenyl)} amino-7-butylaminofluorane, 3- {N-ethyl-N- ( 4-methylphenyl)} amino-7-dibenzylaminofluorane, 3- {N-ethyl-N- (4-methylphenyl)} amino-7- {bis (4-methylbenzyl)} aminofluorane, 3 -{N-ethyl-N- (4-methylphenyl)} amino-7-benzoylaminofluorane, 3- {N-ethyl-N- (4-methylphenyl)} amino-5-methyl-7-dibenzyl Aminoph Oran, 3- {N-ethyl-N- (4-methylphenyl)} amino-5-chloro-7-dibenzylaminofluorane, 3- {N-ethyl-N- (4-methylphenyl)} amino- 6-methylfluorane, 3- {N-ethyl-N- (4-methylphenyl)} amino-5-methoxyfluorane, 3- {N-ethyl-N- (4-methylphenyl)} amino-7, 8-benzofluorane, 3- {N-propyl-N- (4-methylphenyl)} amino-6-methyl-7- {N-emer-N- (4-methylphenyl)} aminofluorane, 3- {N-propyl-N- (4-methylphenyl)} amino-7-aminofluorane, 3- {N-ethyl-N- (4-ethylphenyl)} amino-7-aminofluorane, 3- {N -Methyl-N- (4-ethylphenol L)} amino-7-aminofluorane, 3- {N-ethyl-N- (4-methylphenyl)} amino-7-diethylaminofluorane, 3- {N-ethyl-N- (4-ethylphenyl) } Amino-7-aminofluorane, 3- {N-propyl-N- (4-ethylphenyl)} amino-7-aminofluorane, 3- {N-methyl-N- (2,4-dimethylphenyl) } Amino-7-benzylaminofluorane, 3- {N-ethyl-N- (2,4-dimethylphenyl)}-7-aminofluorane, 3- {N-methyl-N- (2,4-dimethyl) Phenyl)} amino-7-methylaminofluorane, 3- {N-ethyl-N- (2,4-dimethylphenyl)} amino-7-ethylaminofluorane, 3- {N-ethyl-N- (2 , 4-dimethylphenyl) } Amino-7-benzylaminofluorane, 3- {N-propyl-N- (2,4-dimethylphenyl)} amino-7-aminofluorane, 3- {N-methyl-N- (4-chlorophenyl) } Amino-aminofluorane, 3- {N-ethyl-N- (4-chlorophenyl)} amino-7-aminofluorane, 3- {N-propyl-N- (4-chlorophenyl)} amino-7-amino Fluorane, 3-cyclohexylamino-7-bromoaminofluorane, 2,7-dichloro-3-n-butylamino-6-methylfluorane, 3-di-n-butylamino-6,7-butylenefluorane 3-amino-5-methylfluorane, 2-methyl-3-amino-6-methyl-7-methylfluorane, 1,3,3-trimethylindolino-6'-nitrobenzopi Rospiran, 1,3,3-trimethylindolino-6'-nitro-8'-methoxybenzopyrospirane, 1,3,3-trimethylindolino-6'-bromobenzopyrospirane, 1,3,3 -Trimethylindolino-8'-methoxybenzopyrospirane, 1,3,3-trimethylindolino-benzopyrispirane, 1,3,3-trimethylindolino β-naphthopyrilospirane, 3,3-bis (4-Dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (4-dimethylaminophenyl) -6-methylaminophthalide, bis (4-dimethylaminophenyl)-(4-chloro) Phenylmethane-2-carboxylate, bis (4-dimethylaminophenyl)-(4-diethylamino) phenylmethane-2-carboxy Sylate, bis (4-dibutylaminophenyl) phenylmethane-2-carboxylate, {2-hydroxy- (4-diethylamino) phenyl}-(2-methoxy-5-methylphenyl) phenylmethane-2-carboxylate, { 2-hydroxy- (4-dimethoxyamino) phenyl}-(2-hydroxy-5-chlorophenyl) phenylmethane-2-carboxylate, (4-dimethylaminophenyl)-(2-hydroxy-4-chloro-5-methoxy) Phenyl) phenylmethane-2-carboxylate, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3-{(4- Diethylamino-2-ethoxyphenyl) -3- (2-methyl-1-n-octyl) Ndol-3-yl) -4-azaphthalide, 3,3-bis (2-methyl-1-ethylindol-3-yl) phthalide, 3- (4-diethylamino-2-methoxyphenyl) -3- (2- Methyl-1-ethylindol-3-yl) -phthalide, 3- (4-diethylamino-2-methylphenyl) -3- (1,2-dimethylindol-3-yl) -phthalide, 3,3-bis ( 2-methyl-1-octylindol-3-yl) phthalide, rhodamine anilinolactam, rhodamine-2-chloroanilinolactam, rhodamine-4-chloroanilinolactam, bis {2-methyl- (4-dimethylamino) Phenyl}-{(2,5-dimethylamino) phenyl} methane.

  In the reversible thermosensitive composition according to the present invention, the electron accepting compound and / or the electron donating compound may be used in combination of plural kinds of compounds.

  The reversible thermosensitive composition according to the present invention essentially comprises the hydroxyphenylhydroxyalkylamide compound and an electron donating color developing compound. These can be blended at an arbitrary ratio as necessary, but it is preferable that the electron-donating color-forming compound is 4 to 10 moles with respect to 1 mole of the hydroxyalkylamide compound (electron-accepting compound). More preferably, it is 5-7 mol. In addition, if necessary, in order to improve the formation of the recording layer and the color development and decoloring characteristics, matrix polymers, vehicles, dispersants, surfactants, antistatic agents, lubricants, antioxidants, UV absorbers, color developing agents Various additives such as a stabilizer, a decoloring accelerator, and a sensitizer can be further included.

  The reversible thermosensitive composition according to the present invention may further comprise a solvent or vehicle for dissolving or dispersing the above components. When each of the above components is dissolved or dispersed in a solvent, the composition according to the present invention can be used as an ink, for example, a gel ink. The pattern drawn with the ink can be colored or erased by temperature control.

3. Reversible thermosensitive recording material The reversible thermosensitive recording material according to the present invention comprises a recording element containing the hydroxyphenylhydroxyalkylamide compound of the general formula (I) and an electron donating color developing compound. This recording element may contain the reversible thermosensitive composition. This recording material can be colored or discolored and decolored by controlling the temperature. Therefore, the reversible thermosensitive recording material according to the present invention can also be called a reversible thermochromic recording material.

  The reversible thermosensitive recording material according to the present invention can be a recording material having any shape as long as it comprises such a recording element.

  For example, a matrix polymer or a mixture in which an electron-accepting compound and an electron-donating color-forming compound are uniformly dispersed in a vehicle is used as a single film, or coated on a support to form a film-like recording layer. A sheet-like recording material can be obtained.

  Further, a recording element obtained by mixing the electron accepting compound of the general formula (I) with an electron donating color-forming compound and uniformly holding it in a matrix polymer or the like as necessary. Alternatively, a recording element in which an electron-accepting compound and an electron-donating color-forming compound are enclosed in microcapsules can be used as a recording material. Such a recording material is used, for example, as an electrostatic toner. Such powders or microcapsules may contain the matrix polymer or may contain the various additives. Furthermore, these powders or microcapsules can be encapsulated in microcapsules together with further additives as necessary to form recording elements. Such a powder or microcapsule adhered or fixed on a support is also one of the reversible thermosensitive recording materials according to the present invention.

  The matrix polymer or vehicle that can be used in the present invention to disperse or retain the electron-accepting compound and the electron-donating color-forming compound includes an electron-accepting compound, an electron-donating color-forming compound, and, if necessary, The other additives are not particularly limited as long as they can uniformly disperse or maintain the additives and do not inhibit the color development or decoloration of the recording material.

  Specific examples of such a matrix polymer include polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, cellulose polymer, polystyrene, styrene copolymer, acrylic polymer, diene polymer, polyester, polyurethane, and polycarbonate. And polyvinyl alcohol. As the vehicle, those generally used in the printing field can be used.

  In the recording material of the present invention, when the composition containing the electron accepting compound and the electron donating color developing compound is disposed on the support in a layered form, the support may be a transparent, translucent or opaque polymer film or Sheets, synthetic paper and processed paper, glass plates, metal plates, etc. are used, and a recording layer is provided directly on the support, or an undercoat layer is temporarily provided on the support to improve the adhesion between the support and the recording layer. And a recording layer may be provided thereon. It is also preferable to select such an undercoat layer that has an effect of imparting heat insulating properties in addition to improving adhesion.

  Also, when the recording material is in the form of a sheet, recording with a thermal head is possible, but the surface of the recording material and the thermal head are prevented from being fused, the scratch resistance of the recording layer is improved, the recording layer is prevented from being oxidized, A transparent protective layer may be provided on the surface of the recording material in order to prevent the recording layer from being contaminated by harmful gases. The protective layer may be formed by depositing an inorganic material or coating with a polymer solution, or may be formed by laminating polymer films. In order to improve the adhesion between the protective layer and the recording layer, an intermediate layer such as an adhesive layer or an adhesive layer may be provided. In order to improve the properties of the protective layer or the recording layer, various additives such as a surfactant, an antistatic agent, a lubricant, an antioxidant, and an ultraviolet absorber may be added to the protective layer or the intermediate layer. . Moreover, you may provide the ultraviolet absorption layer which consists of ultraviolet absorption polymers as an intermediate | middle layer. Such an ultraviolet absorbing layer may be provided independently of the above-described protective layer or intermediate layer, or may contain the aforementioned additives at the same time. Further, when the recording material is in the form of a sheet, a backcoat layer can be provided in order to improve physical properties such as curling prevention.

Since the reversible thermosensitive recording material of the present invention can be used in the form of a layer on a support, a solution comprising an electron-accepting compound, an electron-donating compound, and other additives as required Alternatively, the reversible thermosensitive recording material can be formed by coating the dispersion on the support by various coating methods such as bar coating and spin coating. The recording layer provided on the support surface is preferably 1 μm to 30 μm in thickness when dried, and more preferably 2 μm to 10 μm. The recording material of the present invention can be displayed by recording with a thermal printer such as a FAX or a thermal transfer printer, a heat roll, etc., or by blowing hot air at a decoloring temperature, heating with a hot stamp, a heat roll, etc. Can be decolored.
In the reversible thermosensitive recording material of the present invention, the colorant is present in the recording layer or in a layer other than the recording layer, for example, a support, an undercoat layer, a protective layer, an adhesive or adhesive layer, and the colorant alone. From color (X) to color (Y) in which the color of the colorant alone and the color of the electron-donating color-forming compound in the colored state are mixed, or vice versa (Y) to (X) Change can be made. The type and amount of the colorant that can be used here are arbitrary, but when present in the recording layer, the coloring reaction between the electron-accepting compound and the electron-donating color-forming compound is not inhibited. Should be selected. In addition, when a colorant is present in the recording layer or a layer other than the recording layer, the color change or contrast change should be selected appropriately.

  The reversible thermosensitive recording material of the present invention forms a recording layer containing the electron-accepting compound of the general formula (I) and the electron-donating color-forming compound in a predetermined character, figure or pattern on a support. It can also be made. That is, when the recording layer is heated to the color development temperature range, part or all of the recording layer is colored or discolored, and recording or display becomes possible. At this time, by forming a plurality of recording layers that develop or change colors into different colors in a pattern such as a stripe or matrix, a plurality of colors can be developed.

  Furthermore, in the present invention, the recording layer can be formed so as to conceal the base in a colored state. Therefore, when a predetermined character, figure, or pattern is formed on the support in advance and the recording layer is uniformly laminated thereon, the recording layer is colored or decolored by temperature control. Part or all of the recording layer is colored, decolored, or discolored, and part or all of the characters, figures, or patterns on the support are concealed or seen through to enable reversible recording or display. In addition, predetermined characters, figures, and patterns can be formed on both the recording layer and the support and used in combination. The recording material as used in the present invention is a term including a display material.

4). Color development / decoloration process The color development / decoloration process according to the present invention involves melting both the electron-donating color-forming compound and the electron-accepting compound in the reversible thermosensitive composition or the reversible thermosensitive recording material with an appropriate heat source. By heating to the temperature at which it reacts, the color is developed and then rapidly cooled, so that the colored state is stably maintained, and the temperature is lower than the color development temperature and is heated to a decoloring temperature range where the reverse reaction with the melting reaction occurs. It will be decolored.

  Examples of the heat source include a thermal head, a laser beam, a heat roller, a heat stamp, hot air, high-frequency heating, radiant heat from a heat transfer heater, a heat pen, a heated thermostat, and infrared irradiation. In particular, when applying heat partially, a thermal head, a laser beam, a thermal pen or the like is preferable.

  As a specific color development method, for example, the recording layer can be partially cooled in a short time with a thermal head or the like, and then rapidly cooled by removing the heat source to obtain a color development state. At that time, it can be sufficiently quenched by keeping the ambient temperature around room temperature, but by performing the local heating in a short time, it is combined with the temperature difference from the non-heating part other than the heating part. Thus, rapid cooling can be ensured. More specifically, the color development temperature in the color development / decoloration process of the present invention is 90 ° C. or higher, preferably 100 to 140 ° C.

On the other hand, in order to change the reversible thermosensitive recording material from the colored state to the decolored state, for example, (1) Once the reversible thermosensitive recording material is contained, the electron donating color-forming compound and the electron accepting property are included. There are two methods: a method in which both compounds are melted, that is, a method in which reheating is performed at a temperature higher than the color development temperature and then gradually cooling from the heating state, and a method (2) in which reheating is performed at a temperature slightly lower than the color development temperature.

  In order to perform the slow cooling of (1), it is possible to use a method such as performing temperature control for storing the surrounding environment or the surrounding portion, such as a support, in the case of reheating by the heat source, and using it. it can. More specifically, after heating to a temperature equal to or higher than the temperature at which the color can be erased, for example, the color development temperature, the temperature of the recording layer is gradually lowered at a rate at which the color is erased.

  In addition, as a method of reheating to a slightly lower temperature in (2), the applied voltage or pulse width of the thermal head is adjusted to a temperature slightly lower than that when the applied energy itself is developed, for example, the decoloring temperature. do it. In the present invention, the decoloring temperature is 60 to 130 ° C, preferably 80 to 120 ° C.

  The methods described in (1) or (2) for changing the material from the colored state to the decolored state are both used when changing from the decolored state to the colored state by adjusting the cooling rate and applied energy. The heating means can be used in common.

  In other words, the development of the decolored state can be obtained by the same thermal control as that for obtaining the colored state except that the temperature condition described in (1) or (2) above is adjusted. The heating means that can be used when obtaining the color developing state and the heating means that can be used when obtaining the decoloring state can be used for both by adjusting the energy applied to the recording material.

  More specifically, when used as a reversible thermosensitive recording material, a thermal printer having a thermal head, such as a normal thermal printer widely used for facsimiles, a thermal transfer printer applied to barcode printing, etc., or a heat Color can be developed by a roll or the like.

  As a method of gradual cooling, the recording material is brought into contact with an electric heater or hot plate heated to a coloring temperature, and then the supply of energy for heating is stopped, and the support and the like are stored in a state where heat is stored. Graduation can be performed by a method such as cooling.

  As a method of heating to a temperature slightly lower than the color development temperature, the color can be erased by a method such as blowing hot air at a decoloring temperature, heating with a hot stamp, a heat roll, a hot plate, or an on-surface heating element.

  In addition, a thermal printer having a thermal head, such as a normal thermal printer widely used for facsimiles and the like, a thermal transfer printer applied to barcode printing, etc., is used to cover the recording material with film, paper, etc. After adjusting the energy applied to the material to the decoloring temperature, the color can be erased by a method such as adding energy to the entire surface of the recording material.

Furthermore, if a thermostat is used, a large amount of recorded matter can be erased at once.
The reversible thermosensitive recording material of the present invention can be used as a sheet-like material having a recording layer, or cards, and further to use as a toner or as a writing material as an ink. Of course, two or more kinds may be combined as appropriate.

  In addition, it is possible to use a combination of different coloring temperatures, and in this case, it is also possible to efficiently express multiple colors.

  The present invention will be described below with reference to examples.

Synthesis example 1
Synthesis of N- (4-hydroxyphenyl) -12-hydroxystearamide 32.7 parts by weight of p-aminophenol, 88.35 parts by weight of 12-hydroxystearic acid, 0.24 parts by weight of p-toluenesulfonic acid, In addition to 200 parts by weight, water was distilled off at 220 ° C. for 2 hours while refluxing, and then xylene was removed to obtain a black waxy substance. This material was recrystallized from methyl ethyl ketone (MEK) to obtain 50 parts by weight (yield 44%) of a white powdery material. The melting point was 141 ° C. The substance was confirmed to be N- (4-hydroxyphenyl) -12-hydroxystearamide by IR and DSC measurements. The obtained IR spectrum and DSC chart are shown in FIGS. Moreover, the measured value obtained from these was as follows.
IR spectrum (absorption position / cm ⁻¹ )
O—H (phenol, alcohol): around 3300 N—H (amide, stretching): around 3300 C—H (methylene): 2920, 2850
C—H (methyl): 2960
C = O (amidocarbonyl): 1670
Phenyl: 1520, 1600
NH (amide, variable angle): 1540
Aromatic p-substituted product: 830
DSC endothermic peak: 141.71 ° C
Endothermic start temperature: 124.89 ° C
End-of-end temperature: 156.03 ° C

Synthesis example 2
Synthesis of N- (3-hydroxyphenyl) -12-hydroxystearamide As in Synthesis Example 1, a black WAX-like product was obtained using p-aminophenol as m-aminophenol. 50 parts by weight of this product was washed with toluene and recrystallized with butyl acetate to obtain 7.8 parts by weight (yield 15.6%) of a light brown powder. The melting point was 117 ° C. The substance was confirmed to be N- (3-hydroxyphenyl) -12-hydroxystearamide by IR and DSC measurements. The obtained IR spectrum and DSC chart are shown in FIGS. Moreover, the measured value obtained from these was as follows.
IR spectrum (absorption position / cm ⁻¹ )
OH (phenol, alcohol): around 3300 N—H (amide, stretching): around 3300 C—H (methylene): 2920, 2850
C—H (methyl): 2960
CO (amidocarbonyl): 1650
Phenyl: 1500, 1610
NH (amide, variable angle): 1550
Phenol: 1230
Aromatic m-substituted product: 770,730
DSC endothermic peak: 117.07 ° C
Endothermic start temperature: 105.38 ° C
Endothermic temperature: 125.62 ° C

Synthesis example 3
Synthesis of N- (4-hydroxyphenyl) -12-hydroxypentadecanamide Similar to Synthesis Example 1 except that 12-hydroxystearic acid was changed to 12-hydroxypentadecanoic acid, N- (4-hydroxyphenyl) -12 -Hydroxypentadecanamide was obtained. The melting point was 151 ° C. The obtained IR spectrum and DSC chart are shown in FIGS. Moreover, the measured value obtained from these was as follows.
IR spectrum (absorption position / cm ⁻¹ )
OH (phenol, alcohol): around 3300 N—H (amide, stretching): around 3300 C—H (methylene): 2920, 2850
C—H (methyl): 2960
CO (amidocarbonyl): 1660
Phenyl: 1500, 1610
NH (amide, variable angle): 1550
Phenol: 1230
Aromatic p-substituted product: 830
DSC endothermic peak: 150.89 ° C.
Endothermic temperature: 147.02 ° C
Endothermic temperature: 155.62 ° C

Example 1
0.01 part by weight of N- (4-hydroxyphenyl) -12-hydroxystearamide prepared in Synthesis Example 1 and 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2- When a composition with 0.004 part by weight of methylindol-3-yl) -4-azaphthalide was placed on a slide glass and heated to 140 ° C., a dark blue color was developed. When this slide glass was quenched with ice water, the color was retained. When the colored product was left in a constant temperature bath at 100 ° C., the color was erased. When the decolored product was heated again to 140 ° C., the color developed as in the initial stage. Thus, it was confirmed that coloring and decoloring of this composition can be repeated.

Example 2
Coloring and decoloring were the same as in Example 1 except that N- (4-hydroxyphenyl) -12-hydroxystearamide in Example 1 was changed to N- (3-hydroxyphenyl) -12-hydroxystearamide. Confirmed. When the composition was placed on a glass slide and heated to 100 ° C., it developed a deep blue color. When this slide glass was quenched with ice water, the color was retained. When the colored product was left on a hot plate at 75 ° C., the color was erased. When the decolored product was heated again to 100 ° C., the color developed as in the initial stage. From these results, it was confirmed that this composition can repeatedly perform coloring and decoloring.

Example 3
Implementation was performed except that N- (4-hydroxyphenyl) -12-hydroxystearamide of Example 1 was changed to N- (4-hydroxyphenyl) -12-hydroxypentadecanamide and heating at 140 ° C. was performed at 120 ° C. When the repeatability of coloring and erasing was confirmed in the same manner as in Example 1, it was confirmed that coloring and erasing could be repeated.

Example 4
Styrene-acrylic ester copolymer: 20 parts by weight (Hymer TB-1000F (trade name) manufactured by Sanyo Chemical Industries, Ltd.)
N- (4-hydroxyphenyl) -12-hydroxystearamide: 10 parts by weight Crystal Violet Lactone (CVL): 3.6 parts by weight The above composition is dissolved in 170 parts by weight of tetrahydrofuran (THF) by heating and is reversible. A solution of the thermal recording material was prepared. This solution is applied to a white polyethylene terephthalate film (manufactured by Toray Industries, Inc.) having a thickness of 100 μm using a wire bar, and then heated and dried at 100 ° C., thereby recording a reversible thermosensitive recording material having a thickness of 4 μm. A layer was provided to produce a recording material. When this recording material was heated to 140 ° C. and cooled to room temperature (20 ° C.), a blue-violet color was developed. When this recording material was heated to 100 ° C. for 1 second, cooled to room temperature, heated to 140 ° C. and then cooled to room temperature, decolorization and color development could be performed reversibly. The optical density of the colored state and the decolored state at this time was measured using a Macbeth densitometer RD-915 (trade name), and showed an OD value of 0.80 in the colored state and 0.07 in the decolored state. An excellent recording material was obtained.

Example 5
Styrene-acrylic ester copolymer (Hymer TB-1000F (trade name) manufactured by Sanyo Chemical Industries, Ltd.): 20 parts by weight N- (4-hydroxyphenyl) -12-hydroxystearamide: 10 parts by weight 3- (4-diethylamino- 2-Ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide (Blue-63 (trade name) manufactured by Yamamoto Kasei Co., Ltd.): 4.2 parts by weight The composition containing this was dissolved in a mixed solvent consisting of 17.6 parts by weight of toluene, 17.6 parts by weight of methyl ethyl ketone, and 67.4 parts by weight of dimethylacetamide to prepare a reversible recording material solution. This solution was applied to a white polyethylene terephthalate film having a thickness of 75 μm using a wire bar, and then heated and dried at 100 ° C. to provide a recording layer made of a reversible thermosensitive recording material having a thickness of 7 μm. Was made. When this recording material was heated to 140 ° C. on a hot plate and cooled to room temperature, a dark blue color was developed. When this recording material was heated at 110 ° C. for 1 second, cooled to room temperature, heated to 140 ° C. and then cooled to room temperature, decoloring and color development could be performed reversibly. The optical density of the colored state and the decolored state at this time was measured using a Macbeth densitometer RD-915 (trade name). The OD was 1.37 in the colored state and 0.07 in the decolored state. An excellent recording material was obtained.

Comparative Example 1
Recording was performed in the same manner as in Example 4 except that N- (4-hydroxyphenyl) -12-hydroxystearamide of Example 4 was changed to 10 parts by weight of N- (4-hydroxyphenyl) -stearamide (melting point 133 ° C.). The material was made. When this recording material was heated to 140 ° C. and cooled to room temperature (20 ° C.), a blue-violet color was developed. When this recording material was heated to 100 ° C., cooled to room temperature, heated to 140 ° C. and then cooled to room temperature, decoloring and color development could be performed reversibly. When the optical density of the colored state and the decolored state at this time was measured using a Macbeth densitometer RD-915, it showed an OD value of 0.65 in the colored state and 0.07 in the decolored state. It was confirmed that the recording material of the present invention was inferior.

Evaluation of Storage Stability The recording materials of Example 4 and Comparative Example 1 were printed with a thermal head (applied energy of 0.25 mJ / dot) and left in a constant temperature bath at 40 ° C. for 24 hours. Was measured using a Macbeth densitometer RD-915 (trade name), and the storage stability of the printed matter was evaluated from the print storage rate. The storage stability was calculated according to the following formula.
Print preservation ratio (%) = {(OD value of printed matter after saving−Base OD value after saving) / (OD value of printed matter before saving−Base OD value before saving)} × 100

Comparative Example 2
A recording material was prepared in the same manner as in Example 4 except that (HO) ₃ PhCOOC ₁₈ H ₃₇ was used as the electron-accepting compound.

Comparative Example 3
A recording material was produced in the same manner as in Example 4 except that the electron-accepting compound was C ₂₂ H ₄₅ P (O) (OH) ₂ .

Comparative Example 4
A recording material was prepared in the same manner as in Example 4 except that the electron-accepting compound was HOPhC ₂ H ₄ NHCOC ₅ H ₁₀ NHCONHC ₁₈ H ₃₇ .

Evaluation of color development temperature, color erasing temperature, erasability, and storage stability Regarding the recording materials of Example 4 and Comparative Examples 2 to 5, the color development temperature (color development temperature), the color erasable temperature (color erase temperature), The time required for erasure (erasability) and the color stability (storage stability) when kept at 40 ° C. were evaluated. The results obtained were as follows.

ここで保存安定性の評価基準は４０℃で２４時間保存したときの印字保存率から、以下の基準により判定した。
○：８０％を超えるもの
△：４０％を超えて８０％以下のもの
×：４０％以下のもの

Here, the storage stability was evaluated based on the following criteria based on the print storage rate when stored at 40 ° C. for 24 hours.
○: Over 80% Δ: Over 40% and 80% or less ×: 40% or less

Examples 6-10
Other than confirmation by changing N-4- (hydroxyphenyl) -12-hydroxystearamide to the amide compound shown in Table 3 and setting the blending amounts in the table to color development and decoloration after heating to the respective temperatures and cooling Were subjected to color development and decoloration tests in the same manner as in Example 5. In addition, the compounding quantity in a table | surface is a weight part with respect to 20 weight part of styrene-acrylic ester copolymers.

※Ｎ４ＨＰ１２ＨＳＡ：Ｎ−（４−ヒドロキシフェニル）−１２−ヒドロキシステアラミド
※Ｎ３ＨＰ１２ＨＳＡ：Ｎ−（３−ヒドロキシフェニル）−１２−ヒドロキシステアラミド
※Ｎ４ＨＰ１２ＨＰＡ：Ｎ−（４−ヒドロキシフェニル）−１２−ヒドロキシペンタデカンアミド

* N4HP12HSA: N- (4-hydroxyphenyl) -12-hydroxystearamide * N3HP12HSA: N- (3-hydroxyphenyl) -12-hydroxystearamide * N4HP12HPA: N- (4-hydroxyphenyl) -12-hydroxypentadecane Amide

Examples 11-17
A recording material was prepared in the same manner as in Example 5 except that the leuco dyes shown in the following table were used. The confirmation of color development was performed by printing using a commercially available FAX (UF-A6CL (trade name), manufactured by Matsushita Electric Industrial Co., Ltd.) without using a film. The decoloring test was performed under the same conditions as in Example 5. In addition, the compounding quantity in a table | surface is a weight part with respect to 20 weight part of styrene-acrylic ester copolymers.

Ｓ−２０５： 山田化学工業（株）製、フルオラン系ロイコ染料
ＯＤＢ： 山本化成（株）製、フルオラン系ロイコ染料
Ｂｌａｃｋ１５： 山本化成（株）製、フルオラン系ロイコ染料
ＯＤＢ−７： 山本化成（株）製、フルオラン系ロイコ染料
ＰＳＤ−１５０： 日本曹達（株）製、フルオラン系ロイコ染料
ＰＳＤ−３００Ａ： 日本曹達（株）製、フルオラン系ロイコ染料
Ｂｌａｃｋ１７３： 山本化成（株）製、フルオラン系ロイコ染料

S-205: Yamada Chemical Co., Ltd., fluoran leuco dye ODB: Yamamoto Kasei Co., Ltd., fluoran leuco dye
Black 15: manufactured by Yamamoto Kasei Co., Ltd., fluoran leuco dye
ODB-7: A fluoran leuco dye manufactured by Yamamoto Kasei Co., Ltd.
PSD-150: Nippon Soda Co., Ltd., fluoran leuco dye PSD-300A: Nippon Soda Co., Ltd., fluoran leuco dye Black 173: Yamamoto Kasei Co., Ltd., fluoran leuco dye

Examples 18-21
Color development and decoloration tests were performed in the same manner as in Example 5 except that the matrix polymer shown in the table below was used.

飽和ポリエステル１： バイロン240、東洋紡績株式会社製
飽和ポリエステル２： バイロンＧＫ-640、東洋紡績株式会社製
飽和共重合ポリエステルウレタン： バイロンＵＲ-1400、東洋紡績株式会社製
ポリスチレン： ハイマーST-120、三洋化成工業株式会社製

Saturated polyester 1: Byron 240, Toyobo Co., Ltd. saturated polyester 2: Byron GK-640, Toyobo Co., Ltd. saturated copolymerized polyester urethane: Byron UR-1400, Toyobo Co., Ltd. polystyrene: Hymer ST-120, Sanyo Made by Kasei Kogyo Co., Ltd.

Examples 22-24
Color development and decoloration tests were conducted in the same manner as in Example 18 except that the mixing ratio of the amide compound and the leuco dye was mixed in the ratio shown in the table below. In addition, the compounding quantity in a table | surface is a weight part with respect to 20 weight part of the saturated polyester 1. FIG.

Examples 25-30
Color development and decoloration tests were performed in the same manner as in Example 5 except that the mixing ratio of the amide compound and the leuco dye was mixed in the ratio shown in the table below. In addition, the compounding quantity in a table | surface is a weight part with respect to 20 weight part of styrene-acrylic ester copolymers.

Example 31 ( Preparation of recording material by amide compound dispersion)
Saturated polyester (Byron GK-640 (trade name) manufactured by Toyobo Co., Ltd.): 15 parts by weight 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-Azaphthalide (Blue-63 (trade name) manufactured by Yamamoto Kasei Co., Ltd.): 3 parts by weight UV absorber (JAST-500 (trade name) manufactured by Johoku Chemical Co., Ltd.): 1 part by weight Composition containing the above components The product was dissolved in a mixed solvent consisting of 50 parts by weight of toluene and 50 parts by weight of methyl ethyl ketone. In this solution,
N- (4-hydroxyphenyl) -12-hydroxystearamide: 8 parts by weight were added, and this mixture was pulverized and dispersed for 90 minutes with a sand grinder (TSG-4H (trade name), manufactured by Imex Corporation). A reversible recording material dispersion having an average particle size of about 1 μm was obtained.
This dispersion was applied to a 75 μm thick white polyethylene terephthalate film using a wire bar, and then heated and dried at 80 ° C. to provide a recording layer made of a reversible thermosensitive recording material having a thickness of 7 μm. The material was made. When this recording material was printed using a commercially available FAX (UF-A6CL (trade name), manufactured by Matsushita Electric Industrial Co., Ltd.) without using a film, the recording material developed a dark blue color. When this recording material was heated with a heat roller of 110 ° C. for 1 second, cooled to room temperature, and repeated printing with the FAX, decoloring and color development could be performed reversibly. The optical density of the colored state and the decolored state at this time was measured using a Macbeth densitometer RD-915 (trade name). The OD was 1.16 in the colored state and 0.09 in the decolored state. An excellent recording material was obtained.

Example 32 ( Preparation of powdery recording material)
Styrene-acrylic ester copolymer (Hymer TB-1000F (trade name) manufactured by Sanyo Chemical Industries, Ltd.): 20 parts by weight N- (4-hydroxyphenyl) -12-hydroxystearamide: 10 parts by weight 3- (4-diethylamino- 2-Ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide (Blue-63 (trade name) manufactured by Yamamoto Kasei Co., Ltd.): 4.2 parts by weight The composition containing this was dissolved in a mixed solvent consisting of 17.6 parts by weight of toluene, 17.6 parts by weight of methyl ethyl ketone, and 67.4 parts by weight of dimethylacetamide to prepare a reversible recording material solution. This solution was poured thinly and uniformly onto a polyethylene sheet and left in a constant temperature bath at 60 ° C. for 3 days to obtain a dark blue dry solid. Using this as a sample mill (SK-M3 (trade name) manufactured by Kyoritsu Riko Co., Ltd.), a powdery reversible thermosensitive recording material was obtained. When this powder was checked for repeatability of color development and decoloration in the same manner as in Example 1, it showed the same behavior as in Example 1.

Example 33 ( Preparation of thermal ink)
Powdered recording material of Example 32: 15 parts by weight Water: 135 parts by weight The mixture containing the above components was pulverized and dispersed for 60 minutes with a sand grinder (TSG-4H (trade name) manufactured by Imex Co., Ltd.). An aqueous dispersion of a reversible recording material having an average particle size of about 1 μm was obtained. 6 parts by weight of 5% aqueous polyvinyl alcohol solution (use Gosenol GM-14 (trade name) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. as polyvinyl alcohol) is mixed with 15 parts by weight of this aqueous dispersion, and the composition is mixed and stirred. Thus, a thermal ink capable of obtaining an image capable of reversible recording was obtained. This solution was applied onto an 80 μm polypropylene film (YUPO FPG80 (trade name) manufactured by YUPO Corporation) using a painting brush to obtain a reversible recorded image. When this image was checked for repeatability of color development and decoloration in the same manner as in Example 1, it showed the same behavior as in Example 1.
Further, after applying the above thermal ink to a 75 μm thick white polyethylene terephthalate film using a wire bar, the recording layer made of a reversible thermosensitive recording material having a thickness of 9 μm is provided by heating and drying at 80 ° C. A recording material was prepared. When this recording material was printed using a commercially available FAX (UF-A6CL (trade name), manufactured by Matsushita Electric Industrial Co., Ltd.) without using a film, the recording material developed a dark blue color. When this recording material was heated with a 120 ° C. heat roller for 1 second, cooled to room temperature, and repeated printing with the FAX, decoloring and color development could be performed reversibly. The optical density of the colored state and the decolored state at this time was measured using a Macbeth densitometer RD-915 (trade name), and the OD was 0.75 in the colored state and 0.06 in the decolored state. An excellent recording material was obtained.

  Although the present invention is not limited, it is presumed from the above results that the color-decoloration mechanism of the reversible recording material of the present invention and the structure of the hydroxyphenylhydroxyalkylamide compound have the following relationship. Yes. The color development temperature has a relationship with the melting point, but it seems that the position of the long-chain alkyl group having a hydroxyl group having a hydrogen bonding function also has an influence. That is, among the hydroxyphenylhydroxyalkylamide compounds of the present invention, N- (4-hydroxyphenyl) -12-hydroxypentadecanamide has a melting point of 10 than that of N- (4-hydroxyphenyl) -12-hydroxystearamide. The color development temperature as a recording material is as low as about 10 ° C., although it is as high as about ° C. This is because the position of the hydrogen bond from the amide group is the same in both cases, but the distance from the end of the alkyl group is shorter for N- (4-hydroxyphenyl) -12-hydroxypentadecanamide, and the stericity of the hydrogen bond. It is considered that the melting point was increased with the amide compound alone because of less obstacles. On the other hand, as a recording material, steric hindrance occurred in the hydrogen bond due to the influence of leuco dye, matrix polymer, etc. Yes. On the other hand, it is considered that the acidity of the amide compound has an influence on the decoloring performance of the recording material. That is, in the hydroxyphenylhydroxyalkylamide compound of the present invention, N- (3-hydroxyphenyl) -12-hydroxystearamide has higher acidity than N- (4-hydroxyphenyl) -12-hydroxystearamide, and as a result However, since it takes a little time to decolorize, there is no problem in practical use, but it is presumed that the decolorization density is slightly increased. Furthermore, as described above, it is effective to have a hydrogen bond group for storage stability. As described above, the hydroxyphenylhydroxyalkylamide compound in the present invention is colored, decolored, and stored stably. The reason why the balance of the properties is good is that the hydrogen bond position, the acidity, and the alkyl chain length are preferable, as can be seen from the above inference.

  The reversible thermosensitive recording material using the electron-accepting compound according to the present invention has excellent color stability and erasability, color development sensitivity, balance between color development temperature and color erasing temperature, and storage stability against heat in a color development state. Yes. Therefore, it can be generally used as a erasable or rewritable recording material. In particular, since the balance between the coloring temperature and the erasing temperature is appropriate, the degree of freedom of hardware for image formation or erasing is increased. In addition, since the coloring sensitivity, erasability and storage stability are compatible at a high level, it can be used for general-purpose thermal printers such as FAX, and the application range can be expanded to various applications.

On the other hand, Patent Document 23 proposes a recording material in which printing and erasing can be repeated in the same manner. By using a special phenol compound as an electron-accepting compound, the erasing speed is improved and heating is performed within 1 second. Shows that the printed image can be almost erased. However, as described in Non-Patent Document 2, the storage stability of this material is not necessarily sufficient at a temperature exceeding 30 ° C. Therefore, it is desired to further improve the storage stability in practical use. In addition, Non-Patent Document 1 discloses, as means for solving these problems (storage stability, erasing speed, or color developing color density), the hydrogen bond in the molecule and the acidity of the electron-accepting compound. Paying attention, by introducing a functional group having hydrogen bonding performance into the long-chain alkyl group of the electron-accepting compound and introducing a methylene chain as a spacer, hydrogen bonding properties are effectively expressed and storage stability is good. The results of material studies have been reported. By using this electron-accepting compound, the storage stability is improved, but the introduction of the functional group and the spacer group raises the melting point by about 20 to 50 ° C. compared to before the introduction. This melting point is correlated with the color development temperature, that is, the color development sensitivity, and as a result, the color development sensitivity tends to decrease. Lowering the color development sensitivity means that the color density is lowered in a thermal head such as a FAX or a thermal printer that is currently used for general purposes, and it is difficult to use it as it is in existing hardware. As a result, problems such as the use of dedicated hardware or the need to use other additives such as a sensitizer to increase sensitivity remain.
Japanese Patent Publication No. 43-7600 US Pat. No. 3,560,229 Japanese Patent Publication No. 51-44706 Japanese Patent Publication No. 51-44707 Japanese Patent Publication No. 51-44708 JP 58-191190 A JP-A-60-257289 Japanese Patent Publication No. 4-30355 Japanese Patent Publication No. 4-30916 JP-A-63-315287 JP-A-5-254244 Japanese Patent Laid-Open No. 5-262632 JP-A-6-48028 JP-A-2-188293 JP-A-2-188294 International Patent Publication No. WO90 / 11898 pamphlet JP-A-4-46986 JP-A-4-303680 JP-A-4-50289 JP-A-4-50290 Japanese Patent Application Laid-Open No. 5-177931 Japanese Patent No. 2981558 Japanese Patent No. 3380277 Ricoh Technical Report 25, 6 (1999) Proceedings of the 3rd meeting of the Electrophotographic Society 1997, 10 (1997)

Claims (15)

A hydroxyphenylhydroxyalkylamide compound represented by the following general formula (I):

(Here, n is an integer of 1 to 3, and A is a linear hydroxyalkyl group in which a hydroxyl group is bonded to a carbon atom other than the terminal carbon.) The hydroxyphenyl hydroxyalkylamide compound according to claim 1, wherein A in the general formula (I) is represented by the following general formula (II).

(Here, m and l are each independently an integer of 0 or more, and k represents an integer of 1 or more.)   The hydroxyphenylhydroxyalkylamide compound according to claim 2, wherein m + 1 is 6 or more and 23 or less.   The hydroxyphenylhydroxyalkylamide compound according to claim 2 or 3, wherein k is 1 or 2.   The hydroxyphenyl hydroxyalkylamide compound according to any one of claims 2 to 4, wherein m is 10, 1 is 5, and k is 1.   The hydroxyphenyl hydroxyalkylamide compound according to any one of claims 2 to 4, wherein m is 10, 1 is 2, and k is 1.   A reversible thermosensitive composition comprising the hydroxyphenylhydroxyalkylamide compound according to any one of claims 1 to 6 and an electron donating color-forming compound.   The reversible thermosensitive composition according to claim 7, wherein the electron donating color-forming compound is a leuco dye.   A reversible thermosensitive recording material comprising a recording element comprising the hydroxyphenylhydroxyalkylamide compound according to any one of claims 1 to 6 and an electron donating color developing compound.   10. A reversible thermosensitive recording material according to claim 9, wherein the recording element further comprises a matrix polymer or a vehicle.   The reversible thermosensitive recording material according to claim 9 or 10, wherein the shape of the recording element is a film.   The reversible thermosensitive recording material according to claim 9 or 10, wherein the shape of the recording element is powder.   A reversible thermosensitive recording material, wherein the recording element according to claim 9 or 10 is encapsulated in a microcapsule.   A reversible thermosensitive recording material comprising the recording element according to any one of claims 8 to 13 disposed on a support.   A reversible thermosensitive recording material comprising a recording element comprising the hydroxyphenyl hydroxyalkylamide compound according to any one of claims 1 to 6 and an electron donating color developing compound, the hydroxyphenyl hydroxyalkylamide Both the compound and the electron donating color-forming compound are heated to a color development temperature at which they undergo a melt reaction, and then developed rapidly after being rapidly cooled, and the color development state is stably maintained. A color erasing process characterized in that the color is erased by heating to a color erasing temperature range where reaction and reverse reaction occur.

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