JPH0967335A - New phenolic compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new phenolic compound expressed by a specific formula, and useful as, e.g., a color developer for reversibly color-developable compositions keeping stable color developability and color fading tendency and adaptable to a wide range of applicable conditions and environmental conditions. SOLUTION: This new phenolic compound is expressed by formula I (pref. formula II). This phenolic compound is obtained, pref. e.g. by dehydrohalogenation between 4-mercaptophenol and a 11-halogeno-1-undecanol (e.g. 11-bromoundecanol) in the presence of an alkali agent (e.g. potassium hydroxide) in a solvent (e.g. ethanol).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel phenolic compound. The phenolic compound of the present invention is an electron-accepting compound useful in a reversible thermosensitive color-forming composition utilizing a color-forming reaction between an electron-donating color-forming compound and an electron-accepting compound, The novel phenolic compound can be used in a reversible thermosensitive recording medium which is capable of forming and erasing a color image by controlling heat energy by using the reversible thermosensitive coloring composition.

[0002]

2. Description of the Related Art Conventionally, an electron-accepting color-forming compound (hereinafter, referred to as an electron-accepting color-forming compound)
A thermal recording medium utilizing a color-forming reaction between a color former or a leuco dye) and an electron-accepting compound (hereinafter also referred to as a developer) is widely known, and can be used in facsimiles, word processors, scientific measuring instruments, etc. Used in printers. However, these conventional recording media that have been put into practical use all have irreversible color development, and once recorded images cannot be erased and used repeatedly.

On the other hand, according to the patent publication, a recording medium capable of reversibly developing and erasing color is also proposed. For example, JP-A-60-193691 discloses gallic acid as a color developer. A recording medium using a combination of phloroglucinol is disclosed in JP-A-61-237684, and a recording medium using a compound such as phenolphthalein or thymolphthalein as a developer is disclosed in JP-A-62-138556.
JP-A-62-138568 and JP-A-6-138568.
No. 2-140881 discloses a recording layer containing a color developer, a color developer and a homogenous compatible solution of a carboxylic acid ester, and JP-A No. 63-173684 uses an ascorbic acid derivative as the color developer. However, JP-A-2-188293 and JP-A-2-188294 disclose that a salt of bis (hydroxyphenyl) acetic acid or gallic acid and a higher fatty acid amine is used as a developer.
However, the conventional reversible thermosensitive recording medium described above has a problem in terms of compatibility between color stability and decoloration, or stability in color density and repetition, and practical recording. It is not satisfactory as a medium.

We have previously used an organic phosphoric acid compound having a long-chain aliphatic hydrocarbon group, an aliphatic carboxylic acid compound or a phenol compound as a developer in JP-A-5-124360. By combining with a certain leuco dye, coloring and decoloring can be easily performed under heating and cooling conditions, and the coloring and decoloring states can be kept stable at room temperature. We proposed a reversible color-forming composition capable of stably repeating colors and a reversible thermosensitive recording medium using the same in a recording layer. This has practical performance in terms of the balance between color stability and color erasure and color density, but it is also improved in terms of compatibility with a wider range of usage environments and the range of application of color erasure conditions. There was room to be. Since then, it has been proposed to use a specific structure for a phenol compound having a long-chain aliphatic hydrocarbon group (JP-A-6-
210954), which had a similar problem.

[0005]

The object of the present invention is to provide a novel phenolic compound. The phenolic compound retains stable color-forming property and decoloring property and is derived from the phenolic compound as a developer for a reversible color-forming composition which can be used in a wide range of use conditions and environmental conditions. It is useful as an intermediate for various materials.

[0006]

In the reversible coloring and decoloring phenomenon of the composition of the color former and the color developer, we have the ability to develop the color of the color former of the color developer having a long chain aliphatic group. We thought that the balance of cohesive forces between molecules was important, and examined compounds with various structures. As a result, they have found that the above problems can be solved by using a specific phenolic compound as a developer. The phenolic compound of the present invention is
By having an associative group in the long-chain alkyl portion, the cohesive force is improved, and the colored and decolored states are stable.
In the present invention, 4- (11-hydroxyundecylmercapto) phenol and 4- (10-carboxydecylmercapto) phenol represented by the following formulas (1) and (2) are provided as novel developers.

[0007]

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[0008]

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Examples of the phenolic compound of the above formula (1) according to the present invention include 4-mercaptophenol and 11-
It can be synthesized by subjecting halogeno-1-undecanol to a dehydrohalogenation reaction in the presence of an alkaline agent in a suitable solvent. As the halogenoundecanol, 11-iodo-, 11-bromo-, 11-chloro- or 11-fluoro-undecanol can be used, preferably 11-bromo- or 11-chloro-undecanol is used, and particularly Preferably 11-bromo-undecanol can be used. Further, the phenolic compound of the above formula (2) according to the present invention is, for example, 4
-Mercaptophenol and 10-halogeno-1-undecanoic acid can be synthesized by a dehydrohalogenation reaction in the presence of an alkaline agent in a suitable solvent. As the halogenoundecanoic acid, 10-iodo-, 10-bromo-, 10-chloro- or 10-fluoro-undecanoic acid can be used, preferably 10-
Bromo- or 10-chloro-undecanoic acid is used,
Particularly preferably, 11-bromo-undecanoic acid can be used.

The phenolic compound of the present invention is useful as a developer for a reversible thermosensitive coloring composition, and the reversible thermosensitive coloring composition is basically prepared by combining the developer and the color former of the present invention. It is composed. Further, the phenolic compound is useful as an intermediate for various materials derived therefrom.

The color-forming agent used in the reversible thermosensitive color-forming composition has an electron-donating property, and is a colorless or light-colored dye precursor (leuco dye) per se and is not particularly limited and is a conventionally known one. , For example, a triphenylmethanephthalide compound, a fluoran compound, a phenothiazine compound, a leukoauramine compound, an indolinophtalide compound, and the like. One example of the color former is shown below.

2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-
(Di-n-butylamino) fluorane, 2-anilino-
3-methyl-6- (Nn-amyl-N-ethylamino) fluoran, 2-anilino-3-methyl-6- (N
-Ethyl-ptoluidino) fluorane, 2- (o-chloroanilino) -3-methyl-6- (di-n-butylamino) fluorane, 2-anilino-3-methyl-6-
(Di-n-amylamino) fluorane, 2-anilino-
3-methyl-6- (Nn-amyl-N-methylamino) fluoran, 2-anilino-3-methyl-6- (N
-Isoamyl-N-methylamino) fluorane, etc.

The reversible thermosensitive coloring composition using the phenolic compound of the present invention can form a relatively colored state and a decolored state depending on the heating temperature and / or the cooling rate after heating. This basic coloring / decoloring phenomenon will be described. FIG. 1 shows the relationship between the color density and the temperature of this composition. When the temperature of the composition in the decolored state (A) is increased, color is developed at the temperature T ₁ at which the composition begins to melt, and the molten color developed state (B) is obtained. When the color is rapidly cooled from the melted color development state (B), the temperature can be lowered to room temperature while maintaining the color development state, and a solid color development state (C) is obtained. Whether or not this color-developed state is obtained depends on the rate of temperature decrease from the molten state, and in slow cooling, decoloring occurs in the process of temperature decrease, and the same decolorized state (A) or rapid-cooled colored state (C) as in the beginning is obtained. In the state of relatively lower concentration than that of the above). On the other hand, when the temperature of the rapidly cooled color development state (C) is again raised, the color disappears at a temperature T ₂ lower than the color development temperature (D to E), and when the temperature is lowered from here, the same color disappearance state (A) as the beginning is obtained. Return. The actual color forming temperature and color erasing temperature can be selected according to the purpose because they vary depending on the combination of the color developer and the color developing agent used. In addition, the density in the molten color development state and the color development density after quenching do not always match, and may differ.

In this composition, the color-developed state (C) obtained by quenching from the molten state is a state in which the color-developing agent and the color-developing agent are mixed in a state in which the molecules can contact with each other, which is in a solid state. Often formed. This state is a state in which the color developer and the color forming agent aggregate to maintain the color development, and it is considered that the color formation is stabilized by the formation of the aggregate structure. on the other hand,
The decolored state is a state in which both phases are separated. This state is a state in which molecules of at least one compound are aggregated to form a domain or crystallized, and it is considered that the color former and the developer are separated and stabilized by aggregation or crystallization. Can be In many cases, the present invention causes more complete decoloration due to phase separation of the two and crystallization of the color developer. In the decoloring by slow cooling from the molten state and the decoloring by raising the temperature from the colored state shown in FIG. 1, the aggregation structure changes at this temperature, and phase separation and crystallization of the developer occur.

When this composition is used as a reversible thermosensitive recording medium, color recording may be formed by heating with a thermal head or the like to a temperature at which it is melted and mixed, and then rapidly cooled. There are two methods for decoloring: a method of gradually cooling from a heated state and a method of heating to a temperature slightly lower than the coloring temperature. However, they are the same in that they both temporarily separate at a temperature at which they phase separate or at least one crystallizes. The quenching in the formation of a colored state is to prevent the phase separation or the crystallization temperature from being maintained. The quenching and slow cooling here are relative to one composition,
The boundary changes depending on the combination of the color former and the developer.

The ratio of the color-developing agent to the color-developing agent in the composition varies depending on the combination of the compounds used, but the molar ratio of the color-developing agent to the color-developing agent is generally from 1 to 2.
0 range, preferably 2 to 10 range,
If the amount of the color developing agent is less or more than this range, the density of the color-developed state decreases, which is a problem.

The reversible thermosensitive recording medium using the phenolic compound of the present invention comprises a support and a recording layer containing the above-mentioned composition as a main component. Examples of the support include paper, resin film, synthetic paper, metal foil, glass, and composites thereof, and any support can be used as long as it can hold the recording layer.

The recording layer may be of any type as long as the composition of the present invention is present, but in general, a state in which a color former and a developer are finely and uniformly dispersed in a binder resin. Used. The color former and the developer may form particles individually, but more preferably form a dispersed state as composite particles. This can be achieved by once melting or dissolving the color former and the developer. To form such a recording layer, a liquid obtained by dispersing and dissolving each material in a solvent, or a liquid obtained by mixing and dispersing or dissolving each material in a solvent is applied to a support and dried. Done by The color former and the developer can be used by being encapsulated in microcapsules.

In the reversible thermosensitive recording medium using the phenolic compound of the present invention, if necessary, an additive for improving or controlling the coating characteristics of the recording layer and the color-decoloring characteristics can be used. Examples of these additives include a dispersant, a surfactant conductive agent, a filler, a lubricant, an antioxidant, a light stabilizer, an ultraviolet absorber, a color development stabilizer, and a decolorization accelerator.

As the binder resin used for forming the recording layer, for example, polyvinyl chloride, polyvinyl acetate,
Vinyl chloride vinyl acetate copolymer, ethyl cellulose, polystyrene, styrene copolymer, phenoxy resin, polyester, aromatic polyester, polyurethane, polycarbonate, polyacrylate, polymethacrylate, acrylic copolymer, maleic acid Copolymers, polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose, starches and the like. The role of these binder resins is to maintain a state in which the materials of the composition are uniformly dispersed without bias due to the application of heat for recording and erasing. Therefore, it is preferable to use a resin having high heat resistance as the binder resin. For example, the binder resin may be cross-linked by heat, ultraviolet rays, electron beams, or the like.

The reversible thermosensitive recording medium using the phenolic compound of the present invention basically has the above-mentioned recording layer provided on a support, but in order to improve the characteristics as a recording medium, A protective layer, an adhesive layer, an intermediate layer, an undercoat layer, a backcoat layer, etc. can be provided.

In printing using a thermal head, the surface of the recording layer may be deformed due to heat and pressure, and so-called dents may be formed. In order to prevent this, it is preferable to provide a protective layer on the surface. For the protective layer, besides polyvinyl alcohol, styrene-maleic anhydride copolymer, carboxy-modified polyethylene, melamine-formaldehyde resin, urea-formaldehyde resin, ultraviolet curable resin, electron beam curable resin and the like can be used. Further, an additive such as an ultraviolet absorber can be contained in the protective layer.

An intermediate layer is provided between the recording layer and the protective layer for the purpose of improving the adhesiveness, preventing alteration of the recording layer by coating the protective layer, and preventing migration of additives in the protective layer to the recording layer. Is also preferable. Further, it is preferable to use a resin having low oxygen permeability for the protective layer and the intermediate layer provided on the recording layer. It becomes possible to prevent or reduce the oxidation of the color former and the developer in the recording layer.

A heat insulating undercoat layer may be provided between the support and the recording layer in order to effectively utilize the applied heat. The heat insulating layer can be formed by applying organic or inorganic fine hollow particles using a binder resin. An undercoat layer may be provided for the purpose of improving the adhesion between the support and the recording layer and preventing the penetration of the recording layer material into the support.

For the intermediate layer and the undercoat layer, the same resin as the resin for the recording layer can be used. The protective layer, the intermediate layer, the recording layer, and the undercoat layer may contain fillers such as calcium carbonate, magnesium carbonate, titanium oxide, silicon oxide, aluminum hydroxide, kaolin, and talc. In addition, a lubricant, a surfactant dispersant and the like can be contained.

In order to form a color image by using the reversible thermosensitive recording material using the phenolic compound of the present invention, it is sufficient to heat once above the color development temperature and then quench it. Specifically, for example, when the recording layer is heated for a short time with a thermal head or a laser beam, the recording layer is locally heated, so that the heat immediately diffuses and rapid cooling occurs, so that the coloring state can be fixed. On the other hand, in order to erase the color, it may be heated and cooled for a relatively long time using an appropriate heat source, or may be temporarily heated to a temperature slightly lower than the coloring temperature. If the recording medium is heated for a long time, the entire temperature of the recording medium rises over a wide range, and the subsequent cooling is slowed down. As a heating method in this case, a heat roller, a heat stamp, hot air, or the like may be used, or heating may be performed for a long time using a thermal head.

[0027]

The present invention will be described in more detail with reference to the following examples. All "%" in the examples are based on the weight.

Example 1 Synthesis of 4- (11-hydroxyundecylmercapto) phenol At room temperature, 1.45 g of 85% potassium hydroxide was dissolved in 100 ml of ethanol, and then 2.78 g of 4-mercaptophenol was added and dissolved. . After 5.0 g of 11-bromo-1-undecanol was added to this mixed solution, the mixture was reacted under an ethanol reflux condition for 3 hours. The reaction solution was cooled to room temperature and then concentrated by a rotary evaporator. The concentrated reaction solution was poured into 500 ml of water and vigorously stirred to obtain a white solid. This white solid was recrystallized from a mixed solvent of ethyl acetate-hexane to obtain 4.5 g of 4- (11-hydroxyundecylmercapto) phenol. Melting point 9
9.6 ° C. Elemental analysis results Hydrogen 9.49%, carbon 68.3
2%, sulfur 10.98% (calculated values: hydrogen 9.52%, carbon 68.87%, sulfur 10.81%) FIG. 2 shows the infrared absorption spectrum measurement results of this compound.

Example 2 Synthesis of 4- (10-carboxydecylmercapto) phenol At room temperature, 2.89 g of 85% potassium hydroxide was dissolved in 150 ml of ethanol, and then 5.30 g of 4-mercaptophenol was added and dissolved. After adding 10.0 g of 10-bromo-1-undecanoic acid to this mixed solution, the mixture was reacted under an ethanol reflux condition for 3 hours. The reaction solution was cooled to room temperature and then concentrated by a rotary evaporator. The concentrated reaction solution was poured into 500 ml of water and vigorously stirred to obtain a white solid. The white solid was recrystallized from a mixed solvent of ethyl acetate-hexane to obtain 9.5 g of 4- (10-carboxydecylmercapto) phenol. Melting point 123.
6 ° C. Elemental analysis results Hydrogen 8.38%, carbon 65.61
%, Sulfur 10.28% (calculated value hydrogen 8.44%, carbon 65.77%, sulfur 10.33%) FIG. 3 shows the infrared absorption spectrum measurement results of this compound.

Application Example 1 2- (o-chloroanilino) -6-dibutylaminofluorane was used as the color former, and 4 of the present invention was used as the color developer.
A reversible thermosensitive coloring composition was prepared by using-(11-hydroxyundecylmercapto) phenol as follows. First, the color former and the developer were weighed so as to have a mixing ratio (molar ratio) of 1: 5, and pulverized and mixed in a mortar. 1.2m thick
m glass plate was heated to a temperature of 170 ° C. on a hot plate. A small amount of the above mixture was melted on the glass plate. All of the mixtures developed color and became black at the same time as melting. Subsequently, a cover glass was put over the molten mixture, the melt was spread to a uniform thickness, and immediately the whole glass plate was immersed in ice water prepared for rapid cooling. After cooling down,
Immediately after taking out from the ice water, the attached water was removed, and a thin film of color was developed to obtain a reversible thermosensitive coloring composition.

Next, the composition having the above-mentioned color-developed state was heated from room temperature to 4 ° C. by using a trace melting point measuring instrument manufactured by Yanagimoto Seisakusho.
As a result of observing while raising the temperature in minutes, it was confirmed that all compositions had a decoloring region from approximately 70 ° C to 90 ° C. Furthermore, when the composition sample in the above-mentioned color-developed state was placed on a hot plate heated to 85 ° C., the color was instantaneously erased. When the decolored composition sample was heated to 170 ° C. again, it turned black. From this, it was confirmed that the reversible thermosensitive color-forming composition has the repeating property of color-decoloring.

Application Example 2 2- (o-chloroanilino) -6-dibutylamino was prepared by using 4- (10-carboxydecylmercapto) phenol instead of 4- (11-hydroxyundecylmercapto) phenol used in Application Example 1. 2-anilino-3-methyl-6-N-ethyl-N- instead of fluoran
A thermosensitive coloring composition was obtained in the same manner as in Application Example 1 except that p-tolylaminofluorane was used. Further, when the erasing area was observed in the same manner as in Application Example 1, it was confirmed that there was an erasing area from approximately 65 ° C to 105 ° C. Furthermore, when the composition sample in the colored state was placed on a hot plate heated to 90 ° C., the color was instantaneously erased. When the decolored composition sample was heated to 170 ° C. again, it turned black.
From this, it was confirmed that the reversible thermosensitive color-forming composition has the repeating property of color-decoloring.

[0033]

As is apparent from the above detailed and specific description, the present invention provides a phenol compound represented by the following formula (1) and a phenol compound represented by the following formula (2).

[0034]

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[0035]

Embedded image The phenolic compound is useful as a developer for a reversible color forming composition and as an intermediate for various materials derived from the phenolic compound. Since the reversible thermosensitive composition using the phenolic compound of the present invention can be repeatedly formed with a stable color-developed state and a good decolorized state, a reversible thermosensitive recording medium using the same can form an image with high contrast. It can be erased by an easy operation. In addition, the color image is stable under normal use conditions, has high durability against repeated recording and erasure, and provides a highly practical rewritable recording medium. The phenolic compound of the present invention is extremely useful as a developer for a reversible heat-sensitive composition.

[Brief description of drawings]

FIG. 1 is a diagram showing color developing / decoloring characteristics of a reversible thermosensitive color developing composition of the present invention.

FIG. 2 is an infrared absorption spectrum diagram of a 4- (11-hydroxyundecylmercapto) phenol compound.

FIG. 3 is an infrared absorption spectrum diagram of a 4- (10-carboxydecylmercapto) phenol compound.

[Explanation of symbols]

 A Decoloring state B Melting color developing state C Solid color developing state D Decoloring process E Decoloring state

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masaru Shimada 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (2)

[Claims] 1. 4- (11-represented by the following formula (1):
Hydroxy undecyl mercapto) phenol. Embedded image 2. 4- (10-) represented by the following formula (2):
Carboxydecyl mercapto) phenol. Embedded image