JP2006273846A - New phenol compound and reversible heat-sensitive recording medium using the same compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new phenol compound having high coloring sensitivity, retaining a stable coloring property and an erasing property and having excellent storage property when used as a developer for reversible heat-sensitive recording medium and to provide a recording medium excellent in high-speed rewriting characteristics by using the phenol compound and to provide the reversible heat-sensitive recording medium having good sensitivity and excellent in erasing property and having good storage property. <P>SOLUTION: The present invention provides an N-heneicosyl-N'-(4-hydroxyphenyl)urea which is a new phenol compound represented by formula (1). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel phenol compound, and more particularly, to control thermal energy using a reversible thermosensitive coloring composition that utilizes a coloring reaction between an electron-donating color-forming compound and an electron-accepting compound. The present invention relates to a reversible thermosensitive recording medium capable of forming and erasing a color image.

  2. Description of the Related Art Conventionally, heat-sensitive recording media using a color developing reaction between an electron donating color developing compound (hereinafter also referred to as a color former or a leuco dye) and an electron accepting compound (hereinafter also referred to as a developer) are widely known. With the development of OA, it is widely used as output paper for facsimiles, word processors, scientific measuring instruments, etc., and recently, as magnetic heat sensitive cards such as prepaid cards and point cards. However, these conventional recording media that have been put to practical use are being reviewed for recycling and reduced usage due to environmental problems. However, since they are irreversible colors, once recorded images are erased. It cannot be used repeatedly, and the area of the recordable part is limited because new information is added to the part where no image is recorded. Therefore, the actual situation is that the amount of information to be recorded is reduced or the card is remade when the recording area runs out. Therefore, it has been desired to develop a reversible thermosensitive recording medium that can be rewritten any number of times, against the background of the dust problem and forest destruction problem that have been actively discussed in recent years.

  By the way, various reversible thermosensitive recording media have been proposed from these requirements. For example, polymer-type reversible thermosensitive recording media using physical changes such as transparency and cloudiness are disclosed (see Patent Documents 1 and 2). In addition, a dye-type reversible thermosensitive recording medium utilizing a chemical change has been newly proposed. Specifically, those using a combination of gallic acid and phloroglucinol as a developer (for example, see Patent Document 3), those using a compound such as phenolphthalein or thymolphthalein as a developer (for example, patents) Reference 4), a recording layer containing a homogeneous solution of color former, developer, and carboxylic acid ester (see, for example, Patent Documents 5, 6, and 7), and an ascorbic acid derivative used as the developer (For example, refer to Patent Document 8), and those using a salt of bis (hydroxyphenyl) acetic acid or gallic acid and a higher aliphatic amine as a developer (for example, refer to Patent Documents 9 and 10).

  Furthermore, the present inventors previously used an organic phosphate compound, aliphatic carboxylic acid compound or phenol compound having a long-chain aliphatic hydrocarbon group as a developer in Patent Document 11, and this and a leuco dye which is a color former. In combination, the color development and decoloring can be easily performed under heating and cooling conditions, and the color development state and the color erasure state can be stably maintained at room temperature, and the color development and color erasure are repeated. A reversible thermosensitive coloring composition and a reversible thermosensitive recording medium using the same for a recording layer have been proposed. Thereafter, it has been proposed to use a phenolic compound having a long chain aliphatic hydrocarbon group having a specific structure (see, for example, Patent Documents 12 and 13).

  That is, Patent Document 12 proposes to use a phenol compound having a specific urea group, and N- (4-hydroxyphenyl) -N′-octadecylurea and N- (4-hydroxyphenyl) -N. '-Docosylurea has been proposed. In a recording medium using N- (4-hydroxyphenyl) -N′-octadecylurea, the image density is high, but the storage stability is poor, and the image density is lowered in an environment of about 40 ° C., or N- (4 -Hydroxyphenyl) -N'-docosylurea has problems such as impracticality because of the high price of the raw material docosyl isocyanate. In addition, the recording medium using other materials described in Patent Document 12 has problems such as a slow erasing speed and a long time for rewriting, insufficient erasing, or low thermal stability of a color image. Was.

That is, a recording medium using such a material has problems such as a slow erasing speed and a long time for rewriting, insufficient erasing, or low thermal stability of a color image. In addition, there has been a problem that, when rewriting at high speed in a low temperature and low humidity environment, the erasability is lowered and unerased parts are generated.
Therefore, the present inventors further use a phenol compound described in Patent Documents 13 and 14 to provide a recording medium that has high contrast between color development and decoloration, can be erased at high speed, and has excellent color stability in the image area. Proposed. The recording medium using this phenolic compound can be erased by a heating member such as a hot stamp, a heat roller, or a ceramic heater, and has excellent practicality.

However, many of the compounds exemplified in Patent Document 14 have a high melting point, and it is necessary to heat to a high temperature during color development and decoloration, and application of high energy is necessary.
To apply high energy, it is necessary to apply a pulse for a long time during recording, so the writing speed is slow, and since the temperature is high, damage to the recording medium is large and dents are easily generated. There has been a problem that the power source of the apparatus becomes large and the rewriting apparatus becomes large.
On the other hand, as described above, a phenol compound having a relatively low melting point has been proposed as a phenol compound described in Patent Document 12. However, although recording media using these compounds have good color development sensitivity, they have good image storage stability. It was bad and was not practical. In particular, in Patent Document 12, a phenol compound having a urea group substituted with a long-chain alkyl group has been studied. In the case of a compound having 18 carbon atoms, the color density and decoloring property are excellent, but the image storability is high. In the case of a compound having 22 carbon atoms, the recording medium characteristics such as color density, decoloring property, and image storage stability are improved. However, since docosyl isocyanate as a raw material is expensive, it is practical. There was a problem of lacking.

JP 63-107584 A JP-A-4-78573 Japanese Patent Laid-Open No. 60-193691 Japanese Patent Laid-Open No. Sho 61-237684 JP-A-62-138556 JP-A-62-138568 JP-A-62-140881 Japanese Patent Laid-Open No. 63-173684 JP-A-2-188293 JP-A-2-188294 JP-A-5-124360 Japanese Patent Laid-Open No. 6-210954 JP-A-10-95175 JP-A-10-67177

  Accordingly, an object of the present invention is a novel phenol having high color development sensitivity, stable color development and erasability, and excellent storage stability when used as a developer for a reversible thermosensitive recording medium. It is to provide a compound, and to provide a recording medium excellent in high-speed rewriting characteristics using the compound, and further, reversible thermosensitive recording with excellent sensitivity and erasability and good storage stability. To provide a medium.

  In the reversible coloring and decoloring phenomenon of such a color former and developer composition, the present inventors have shown that the ability of the developer having a long-chain aliphatic group to develop color and intermolecular aggregation. We thought that balance of force was important, and designed, synthesized, and studied compounds with various structures. As a result, it has been found that the above problem can be solved by using a phenol compound having a specific structure as a developer. In addition, as a result of various studies using a developer that has a relatively low melting point and high color sensitivity and good erasability, and that it is important to make the recording medium structure highly durable, It was found that the above problem can be solved by using N- (4-hydroxyphenyl) -N′-heneicosylurea as a resin and further using a resin in a crosslinked state in the recording layer. As a result of various investigations considering that it is important to use the heat efficiently and to uniformly heat the recording layer, N- (4-hydroxyphenyl) -N′-heneicosyl urea was used as a developer. Furthermore, it discovered that said subject could be solved by providing the under layer containing a hollow particle between the said support body and the said recording layer. Furthermore, it was found that the balance between the strength of the interaction between the developer molecules and the strength of the coloring state due to the interaction with the dye is important for speeding up the color density and erasing. As a result of examining the compounds, 2-anilino-3-methyl-6-N, N, -di-n-pentylaminofluorane was used as a dye, and N- (4-hydroxyphenyl) was used as a developer. It has been found that the above problem can be solved by using -N'-heneicosyl urea.

Thus, the above object is achieved by the present invention described below.
(1) N-heneicosyl-N ′-(4-hydroxyphenyl) urea which is a novel phenol compound represented by the following formula (1).

（２）支持体上に、電子供与性呈色化合物と電子受容性化合物を用い、加熱温度および／または加熱後の冷却速度の違いにより、相対的に発色した状態と消色した状態を形成しうる可逆性感熱記録層を有する可逆性感熱記録媒体において、該電子受容性化合物が、上記式（１）のＮ−ヘンエイコシル−Ｎ’−（４−ヒドロキシフェニル）尿素を少なくとも含むものであることを特徴とする可逆性感熱記録媒体。
（３）前記記録層が、架橋状態にある樹脂（Ａ）を含有するものであることを特徴とする前記第（２）項に記載の可逆性感熱記録媒体。
（４）前記記録層中に含有される樹脂（Ａ）が、水酸基価７０（ＫＯＨｍｇ／ｇ）以上であることを特徴とする請求項３に記載の可逆性感熱記録媒体。
（５）前記記録層中に含有される樹脂（Ａ）が、アクリルポリオール樹脂であることを特徴とする前記第（３）項又は第（４）項に記載の可逆性感熱記録媒体。
（６）前記記録層中に含有される樹脂（Ａ）が、イソシアネート化合物によって架橋されていることを特徴とする前記第（３）項乃至第（５）項のいずれかに記載の可逆性感熱記録媒体。
（７）前記支持体と前記記録層との間に中空粒子を含むアンダー層を設けることを特徴とする前記第（２）項乃至第（６）項のいずれかに記載可逆性感熱記録媒体。
（８）前記中空粒子の数平均粒径は、０．２μｍ以上５０μｍ以下であることを特徴とする前記第（７）項に記載の可逆性感熱記録媒体。
（９）前記中空粒子の体積中空率は、７０％以上９５％以下であることを特徴とする前記第（７）項又は第（８）項に記載の可逆性感熱記録媒体。
（１０）前記中空粒子が炭酸カルシウム、タルク、酸化チタンからなる群から選択される物質によって被覆されているものであることを特徴とする前記第（７）項乃至第（９）項のいずれかに記載の可逆性感熱記録媒体。
（１１）前記中空粒子の隔壁の厚さは、０．０５μｍ以上３μｍ以下であることを特徴とする前記第（７）項乃至第（１０）項のいずれかに記載の可逆性感熱記録媒体。
（１２）前記電子供与性呈色性化合物として２−アニリノ−３−メチル−６−Ｎ，Ｎ，−ジ−ｎ−ペンチルアミノフルオランを用いることを特徴とする前記第（２）項乃至第（１１）項のいずれかに記載の可逆性感熱記録媒体。
（１３）前記可逆性感熱記録層上に保護層を有し、該保護層が架橋状態にある樹脂（Ｂ）を少なくとも含有すものであることを特徴とする前記第（２）項乃至第（１２）項のいずれかに記載の可逆性感熱記録媒体。
（１４）前記可逆性感熱記録層上に保護層を有し、該保護層が、紫外線吸収性ポリマー（Ｃ）を含有するものであることを特徴とする前記第（２）項乃至第（１３）項のいずれかに記載の可逆性感熱記録媒体。
（１５）前記可逆性感熱記録層上に保護層を有し、該保護層が紫外線吸収能を有する無機微粒子を含有することを特徴とする前記第（２）項乃至第（１４）項のいずれかに記載の可逆性感熱記録媒体。
（１６）情報記憶部を設けたことを特徴とする前記第（２）項乃至第（１５）項のいずれかに記載の可逆性感熱記録媒体。
（１７）表面に、接着剤層又は粘着剤層を設けたことを特徴とする請求項２乃至１６のいずれかに記載の可逆性感熱記録媒体。
（１８）前記第（２）項乃至第（１７）項のいずれかに記載の可逆性感熱記録媒体を用いて、画像の形成及び／又は消去を行なうことを特徴とする画像処理方法。
（１９）サーマルヘッドを用いて前記可逆性感熱記録媒体に画像を形成することを特徴とする前記第（１８）項に記載の画像処理方法。
（２０）サーマルヘッド又はセラミックヒータを用いて前記可逆性感熱記録媒体に形成された可逆画像を消去することを特徴とする前記第（１８）項に記載の画像処理方法。
（２１）前記第（１８）項乃至第（２０）項のいずれかに記載の画像処理方法を用いて、画像の形成及び／又は消去を行なうことを特徴とする画像処理装置。

(2) On the support, an electron-donating color-forming compound and an electron-accepting compound are used to form a relatively colored state and a decolored state depending on the heating temperature and / or the cooling rate after heating. A reversible thermosensitive recording medium having a reversible thermosensitive recording layer, wherein the electron-accepting compound contains at least N-heneicosyl-N ′-(4-hydroxyphenyl) urea of the above formula (1). Reversible thermosensitive recording medium.
(3) The reversible thermosensitive recording medium as described in (2) above, wherein the recording layer contains a resin (A) in a crosslinked state.
(4) The reversible thermosensitive recording medium according to claim 3, wherein the resin (A) contained in the recording layer has a hydroxyl value of 70 (KOHmg / g) or more.
(5) The reversible thermosensitive recording medium as described in (3) or (4) above, wherein the resin (A) contained in the recording layer is an acrylic polyol resin.
(6) The reversible thermosensitive material according to any one of (3) to (5), wherein the resin (A) contained in the recording layer is crosslinked with an isocyanate compound. recoding media.
(7) The reversible thermosensitive recording medium according to any one of (2) to (6), wherein an under layer containing hollow particles is provided between the support and the recording layer.
(8) The reversible thermosensitive recording medium as described in (7) above, wherein the number average particle diameter of the hollow particles is 0.2 μm or more and 50 μm or less.
(9) The reversible thermosensitive recording medium as described in (7) or (8) above, wherein the volumetric hollowness of the hollow particles is 70% or more and 95% or less.
(10) Any one of (7) to (9) above, wherein the hollow particles are coated with a substance selected from the group consisting of calcium carbonate, talc, and titanium oxide. A reversible thermosensitive recording medium according to 1.
(11) The reversible thermosensitive recording medium according to any one of (7) to (10), wherein the partition walls of the hollow particles have a thickness of 0.05 μm to 3 μm.
(12) Items (2) to (2) above, wherein 2-anilino-3-methyl-6-N, N, -di-n-pentylaminofluorane is used as the electron donating color developing compound. The reversible thermosensitive recording medium according to any one of (11).
(13) Item (2) to Item (2), further comprising a protective layer on the reversible thermosensitive recording layer, wherein the protective layer contains at least a resin (B) in a crosslinked state. The reversible thermosensitive recording medium according to any one of items 12).
(14) The above (2) to (13), wherein a protective layer is provided on the reversible thermosensitive recording layer, and the protective layer contains an ultraviolet absorbing polymer (C). The reversible thermosensitive recording medium according to any one of items 1).
(15) Any of (2) to (14) above, wherein a protective layer is provided on the reversible thermosensitive recording layer, and the protective layer contains inorganic fine particles having ultraviolet absorbing ability. A reversible thermosensitive recording medium according to claim 1.
(16) The reversible thermosensitive recording medium according to any one of (2) to (15), wherein an information storage unit is provided.
(17) The reversible thermosensitive recording medium according to any one of (2) to (16), wherein an adhesive layer or a pressure-sensitive adhesive layer is provided on the surface.
(18) An image processing method, wherein an image is formed and / or erased using the reversible thermosensitive recording medium according to any one of (2) to (17).
(19) The image processing method as described in (18) above, wherein an image is formed on the reversible thermosensitive recording medium using a thermal head.
(20) The image processing method according to item (18), wherein the reversible image formed on the reversible thermosensitive recording medium is erased using a thermal head or a ceramic heater.
(21) An image processing apparatus for forming and / or erasing an image using the image processing method according to any one of (18) to (20).

  The phenolic compounds of the present invention are new and useful compounds. Further, as is clear from the following detailed and specific theory, the reversible thermosensitive recording medium using the compound of the present invention as a developer has good color sensitivity and color density, and has excellent image storage stability. Excellent rewrite recording with high practicality can be obtained, a highly practical rewritable recording medium can be obtained, rewriting recording medium with good color density and excellent durability can be rewritten. It is possible to record, furthermore, high sensitivity recording is possible, it has excellent high-speed erasability in a wide environment range, excellent rewriting characteristics at high speed, rewriting characteristics at high speed It exhibits an extremely excellent effect that it is excellent in.

  The present invention relates to a novel phenol compound represented by the following formula (1), and also relates to an excellent reversible thermosensitive recording medium using the same. The reversible thermosensitive recording medium 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.

  This novel compound, N-heneicosyl-N ′-(4-hydroxyphenyl) urea (1), is a coupling reaction between behenic acid, which is a fatty acid, and p-aminophenol using a transfer reaction from an azide compound. Can be synthesized from When both the hydroxyl group and the amino group are present, the urethane bond formation reaction and the condensation reaction become competitive, but in the case of p-aminophenol, the electron donating property of the hydroxyl group is reduced due to the resonance structure of the benzene ring. The condensation reaction proceeds predominantly, and the phenol compound of the present invention can be obtained with high selectivity. The phenol compound of the present invention is not limited to this synthesis method.

The reversible thermosensitive recording medium using the developer, which is the phenol 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 of this recording medium and the temperature. Introduction gradually heated the recording medium in the decolored state (A), leuco dye and the developer are mixed melt at temperatures T ₁ begins to melt, coloring occurs a molten color developed state (B). When rapidly cooled from the melt color state (B), the color state can be lowered to room temperature and a fixed color state (C) is obtained. Whether or not this color development state is obtained depends on the rate of temperature decrease from the molten state, and in slow cooling, the color disappears during the temperature decrease, and the same color disappearance state (A) or rapid color development state (C ) A relatively low concentration state is formed. On the other hand, rapidly cooled colored state (C) is again raised gradually and discoloring occurs at a lower temperature T ₂ than the coloring temperature (E from D), returns the beginning when the temperature decreases from here to the same decolored state (A). The actual color developing temperature and color erasing temperature vary depending on the combination of the developer and color former used, and can be selected according to the purpose. Further, the density of the melt coloring state and the coloring density when rapidly cooled are not necessarily the same and may be different.

  In the recording medium using the developer of the present invention, the colored state (C) obtained by quenching from the melted state is a state in which the developer and the color former are mixed in a state where they can contact each other between molecules, This often forms a solid state. This state is a state where the developer and the color former are aggregated to maintain the color development, and it is considered that the color development is stabilized by the formation of this aggregated 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 aggregate to form a domain or crystallize, and the color former and developer are separated and stabilized by aggregation or crystallization. It is done. In the compound of the present invention, complete decolorization occurs when both of them are phase-separated and the developer is crystallized. In both 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.

  The developer is composed of a phenol group that is a color development site, a hydrogen bonding associative group that controls the structure, and a long-chain aliphatic hydrocarbon group as an important basic skeleton that imparts color developability and color erasability. So far, efforts have been focused on the balance between the phenolic group that is the coloring site and the hydrogen-bonding associative group that is dominant in the structure. The reason is that it has been considered that the stability of the color development state becomes more stable as the aggregation structure of the developer and color former is more stable. Therefore, it has been studied so far to introduce one or more hydrogen bonding associative groups into the developer molecular structure. However, the problem is that the developer molecules have a high melting point due to the strong hydrogen bonds of the developer molecules and the increase in the number of hydrogen bonds, and the color development start temperature increases and the sensitivity characteristics of the recording medium deteriorate. Occurred. For this reason, the present inventors have focused on long-chain aliphatic hydrocarbon groups that have been considered to dominate another structure, and have long-chain alkyl-substituted urea groups that are particularly excellent in color development and decoloring properties. The alkyl chain length of the phenol compound was investigated.

  As a result, it has been clarified that by extending the alkyl chain length, the color density, color sensitivity, image storability, and color erasability are extremely excellent. When the alkyl chain length was about 14 carbon atoms, the color density and decolorability were both low, and the storage stability of the color image was extremely low. This is because the agglomerated structure formed by the developer and dye in the colored state is low in stability, and a sufficient colored state cannot be formed. It is thought that it is not.

  In addition, when the alkyl chain length is 18 carbon atoms, the color density and decoloring property are good, but there is a problem in the storage stability of the image, and the color fading of the image is large and practical in an environment of 50 ° C. It was not tolerable. As a result of further investigations, it has been clarified that, when the number of carbon atoms is 21, the color developability and decolorability are further improved, and in addition, the image storage stability is enhanced.

  Image storage at 50 ° C is important as an index of reliability in normal office applications, tags, and cards. The ability to clear this image storage at 50 ° C has great implications for practical use. Is.

  On the other hand, for practical use, the material needs to be manufactured at a relatively low cost. Conventionally, phenol compounds having these long-chain alkyl-substituted urea groups have been synthesized by a reaction between a long-chain alkyl isocyanate and aminophenol. However, in this method, the long-chain alkyl isocyanate that can be obtained at low cost has only 18 carbon atoms, and those having 21 or more carbon atoms that are excellent in recording medium characteristics include 22 carbon atoms. It was impossible. In addition, as a method for obtaining long-chain alkyl isocyanates having different chain lengths by a conventionally known method, there is a possibility of synthesis by subjecting a long-chain alkylamine to isocyanate using phosgene. The long-chain alkylamine is expensive, and special synthesis equipment is required to use phosgene, which makes it a very expensive material and is extremely difficult to put into practical use.

  Therefore, as a result of examining various synthetic methods, the present inventors have found that a phenol compound having a desired long-chain alkyl-substituted urea group can be synthesized from a long-chain fatty acid and aminophenol using a transfer reaction from an azide compound. I found it. Using this method, N-heneicosyl-N ′-(4-hydroxyphenyl) urea having 21 carbon atoms can be easily synthesized by the reaction of behenic acid, which is available at a low cost, with 4-aminophenol. It was. By using this developer, the stability of the colored state increased and the storage stability of the colored state was dramatically improved despite the low melting point. These studies have made it possible to produce a reversible thermosensitive recording medium that is practical in raw material and manufacturing cost, and that has high sensitivity and heat-resistant storage stability.

  That is, in the present invention, a urea group is introduced into the molecular structure of the developer, and the skeleton has an aliphatic hydrocarbon group having 21 aliphatic hydrocarbons, so that the developer does not have a high melting point. In addition, the coloring stability is improved, and it is possible to achieve both coloring sensitivity and storage stability of the image area.

  Here, the phenol compound used as the developer in the present invention is represented by the following formula (1).

The color former used together with the present invention exhibits an electron donating property and can be used alone or in combination. The color former itself is a colorless or light-colored dye precursor, and is not particularly limited. For example, the color former is a known dye precursor such as a phthalide compound, an azaphthalide compound, or a fluorane compound. Examples of these compounds are leuco dyes described in JP-A Nos. 5-124360, 6-220954, and 10-230680.
Specific examples of the leuco dye used together with the present invention include the following, but are not limited thereto.
2-anilino-3-methyl-6-diethylaminofluorane,
2-anilino-3-methyl-6-di (n-butylamino) fluorane,
2-anilino-3-methyl-6-N, N, -di-n-pentylaminofluorane 2-anilino-3-methyl-6- (Nn-propyl-N-methylamino) fluorane,
2-anilino-3-methyl-6- (N-isopropyl-N-methylamino) fluorane,
2-anilino-3-methyl-6- (N-isobutyl-N-methylamino) fluorane,
2-anilino-3-methyl-6- (Nn-amyl-N-methylamino) fluorane,
2-anilino-3-methyl-6- (N-sec-butyl-N-methylamino) fluorane,
2-anilino-3-methyl-6- (Nn-amyl-N-ethylamino) fluorane,
2-anilino-3-methyl-6- (N-iso-amyl-N-ethylamino) fluorane,
2-anilino-3-methyl-6- (Nn-propyl-N-isopropylamino) fluorane,
2-anilino-3-methyl-6- (N-cyclohexyl-N-methylamino) fluorane,
2-anilino-3-methyl-6- (N-ethyl-p-toluidino) fluorane,
2-anilino-3-methyl-6- (N-methyl-p-toluidino) fluorane,
2- (m-trichloromethylanilino) -3-methyl-6-diethylaminofluorane,
2- (m-trifluoromethylanilino) -3-methyl-6-diethylaminofluorane,
2- (m-trichloromethylanilino) -3-methyl-6- (N-cyclohexyl-N-methylamino) fluorane,
2- (2,4-dimethylanilino) -3-methyl-6-diethylaminofluorane,
2- (N-ethyl-p-toluidino) -3-methyl-6- (N-ethylanilino) fluorane,
2- (N-ethyl-p-toluidino) -3-methyl-6- (N-propyl-p-toluidino) fluorane,
2-anilino-6- (Nn-hexyl-N-ethylamino) fluorane,
2- (o-chloroanilino) -6-diethylaminofluorane,
2- (o-chloroanilino) -6-dibutylaminofluorane,
2- (m-trifluoromethylanilino) -6-diethylaminofluorane,
2,3-dimethyl-6-dimethylaminofluorane,
3-methyl-6- (N-ethyl-p-toluidino) fluorane,
2-chloro-6-diethylaminofluorane,
2-bromo-6-diethylaminofluorane,
2-chloro-6-dipropylaminofluorane,
3-chloro-6-cyclohexylaminofluorane,
3-bromo-6-cyclohexylaminofluorane,
2-chloro-6- (N-ethyl-N-isoamylamino) fluorane,
2-chloro-3-methyl-6-diethylaminofluorane,
2-anilino-3-chloro-6-diethylaminofluorane,
2- (o-chloroanilino) -3-chloro-6-cyclohexylaminofluorane,
2- (m-trifluoromethylanilino) -3-chloro-6-diethylaminofluorane,
2- (2,3-dichloroanilino) -3-chloro-6-diethylaminofluorane,
1,2-benzo-6-diethylaminofluorane,
3-diethylamino-6- (m-trifluoromethylanilino) fluorane,
3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide,
3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -7-azaphthalide,
3- (1-octyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide,
3- (1-ethyl-2-methylindol-3-yl) -3- (2-methyl-4-diethylaminophenyl) -4-azaphthalide,
3- (1-ethyl-2-methylindol-3-yl) -3- (2-methyl-4-diethylaminophenyl) -7-azaphthalide,
3- (1-ethyl-2-methylindol-3-yl) -3- (4-diethylaminophenyl) -4-azaphthalide,
3- (1-ethyl-2-methylindol-3-yl) -3- (4-Nn-amyl-N-methylaminophenyl) -4-azaphthalide,
3- (1-methyl-2-methylindol-3-yl) -3- (2-hexyloxy-4-diethylaminophenyl) -4-azaphthalide,
3,3-bis (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide,
3,3-bis (2-ethoxy-4-diethylaminophenyl) -7-azaphthalide and the like.

  Among these, 2-anilino-3-methyl-6-N, N, -di-n-pentylaminofluorane can be particularly preferably used, and N- (4-hydroxyphenyl) -N ′ as a developer. The reversible thermosensitive recording medium of the present invention can be produced by dissolving or dispersing heneicosyl urea together with a resin using an organic solvent or water, and then coating and drying on a support.

  The ratio of the developer and the color former containing the phenol compound, which is the compound of the present invention, varies in an appropriate range depending on the combination of the compounds to be used. However, the compound of the present invention is generally in a molar ratio with respect to the color former 1. It is in the range of 0.1 to 20, preferably in the range of 0.2 to 10. If the amount of the developer is less or more than this range, the density of the colored state is lowered, which causes a problem. In addition, the color former and the developer can be used in a microcapsule.

  In the recording medium using the developer which is the compound of the present invention, the binder resin used for forming the reversible thermosensitive recording layer together with the leuco dye and the developer is, for example, polyvinyl chloride, polyvinyl acetate, vinyl chloride acetic acid. Vinyl copolymer, ethyl cellulose, polystyrene, styrene copolymer, phenoxy resin, polyester, aromatic polyester, polyurethane, polycarbonate, polyacrylate ester, polymethacrylate ester, acrylic acid copolymer, maleic acid copolymer There are coalesced, polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose, starches and the like. The role of these binder resins is to keep the materials of the composition uniformly dispersed without being displaced by 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 resin (A) in a crosslinked state may be obtained by crosslinking the binder resin with heat, ultraviolet light, electron beam, or the like.

  Specific examples of the crosslinked resin (A) used in the recording medium using the developer which is the compound of the present invention include acrylic polyol resin, polyester polyol resin, polyurethane polyol resin, phenoxy resin, and polyvinyl butyral resin. , A resin having a group that reacts with a crosslinking agent such as cellulose acetate propionate and cellulose acetate butyrate, or a resin obtained by copolymerization of a monomer having a group that reacts with a crosslinking agent and other monomers. It is not limited.

  Further, preferably, a resin having a hydroxyl value of 70 (KOHmg / g) or more is contained (initially used). As the resin having a hydroxyl value of 70 (KOHmg / g) or more, acrylic polyol resin, polyester polyol resin, polyurethane A polyol resin or the like is used. When the compound of the present invention is used, an acrylic polyol resin is preferably used because of good color development stability and good decoloring properties. The hydroxyl value is 70 (KOHmg / g) or more, particularly preferably 90 (KOHmg / g) or more. The magnitude of the hydroxyl value affects the crosslink density and thus affects the chemical resistance and physical properties of the coating film. The present inventors have found that durability, coating film surface hardness, and crack resistance are improved when the hydroxyl value is 70 (KOHmg / g) or more. Whether or not it is a reversible thermosensitive recording medium using a resin having a hydroxyl value of 70 (KOHmg / g) or more can be confirmed by analyzing the amount of residual hydroxyl groups and the amount of ether bonds.

  Examples of the curing agent used in the present invention include conventionally known isocyanates, amines, phenols, and epoxy compounds. Of these, isocyanate curing agents are preferably used. The isocyanate compound used here is selected from known modified monomers such as urethane modified products, allophanate modified products, isocyanurate modified products, burette modified products, carbodiimide modified products, and blocked isocyanates. In addition, as the isocyanate monomer forming the modified product, toluene diisocyanate TDI), 4,4′-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI), naphthylene diisocyanate (NDI), paraphenylene diisocyanate (PPDI) Tetramethylxylylene diisocyanate (TMXDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), lysine diisocyanate (LDI), isopropylidenebis (4-cyclohexylisocyanate) (IPC), Examples include cyclohexyl diisocyanate (CHDI) and tolidine diisocyanate (TODI). It is not limited to the compounds.

  Furthermore, you may use the catalyst used for this kind of reaction as a crosslinking accelerator. Examples of the crosslinking accelerator include tertiary amines such as 1,4-diaza-bicyclo [2,2,2] octane, and metal compounds such as organic tin compounds. Further, the total amount of the curing agent may or may not undergo a crosslinking reaction. That is, an unreacted curing agent may be present. Since this type of crosslinking reaction proceeds over time, the presence of an unreacted curing agent does not indicate that the crosslinking reaction has progressed at all, but an unreacted curing agent is detected. However, this does not mean that there is no resin in a crosslinked state. Further, as a method for distinguishing whether the polymer in the present invention is in a crosslinked state or in a non-crosslinked state, it can be distinguished by immersing the coating film in a highly soluble solvent. That is, since the polymer in the non-crosslinked state dissolves in the solvent and does not remain in the solute, the presence or absence of the polymer structure of the solute may be analyzed.

  In addition, acrylic polyol resins have different characteristics depending on the structure. Hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), 2-hydroxyethyl methacrylate (HEMA), 2-hydroxypropyl methacrylate ( HPMA), 2-hydroxybutyl monoacrylate (2-HBA), 1,4-hydroxybutyl monoacrylate (1-HBA), etc. are used, but it is particularly preferable to use a monomer having a primary hydroxyl group. Since the crack resistance and durability are good, 2-hydroxyethyl methacrylate is preferably used.

In the reversible thermosensitive recording medium of the present invention, an under layer containing hollow particles is preferably provided on a support, and N- (4-hydroxyphenyl)-is used as a developer as a developer on the under layer. A reversible thermosensitive recording layer containing N′-heneicosyl urea is provided, and a protective layer or the like is formed on the thermosensitive recording layer as necessary.
By using N- (4-hydroxyphenyl) -N′-heneicosyl urea, which is a developer having a relatively low melting point as a developer, highly sensitive color development is possible, and an under layer containing hollow particles is further formed. By using it, the diffusion of heat to the support or the like can be prevented, and the heat from the thermal head can be used with high efficiency. Due to the heat insulation effect of the under layer, the temperature distribution in the recording layer during heating is small and uniform heating is possible, and there is no partial color development or erasure residue in the recording layer during erasing, especially in a wide temperature and humidity environment. Good rewriting becomes possible.

Here, the case where hollow particles are contained in the under layer of the reversible thermosensitive recording medium of the present invention will be described.
The hollow particles contained in the under layer are those obtained by microencapsulating a low boiling point liquid such as butane or pentane with a resin or copolymer such as polyvinylidene chloride, polyacrylonitrile, or polymethyl methacrylate. There are pre-foamed hollow particles and non-foamed hollow particles. However, when added in the unfoamed state and foamed with heat during recording medium preparation or printing, uniform foaming is difficult and inferior image quality. A better image quality can be obtained by adding particles.

  The hollow particles preferably have a particle size of 0.2 to 50 μm, and if it is less than 0.2 μm, it is difficult to obtain sufficient cushioning properties and heat insulation properties. On the other hand, when the thickness exceeds 50 μm, the smoothness of the coating film is lowered, and the uniform cushioning property is impaired, and image omission and non-uniform erasure are likely to occur.

  Further, the volume hollowness of the hollow particles is preferably 50% or more, and if the volume hollowness is lower than this, sufficient cushioning properties and heat insulation properties are difficult to obtain. Moreover, the thing with a hollow rate of 70%-95% is especially preferable.

  Moreover, since hollow particles have a small specific gravity and are difficult to handle in operation, hollow particles having a high specific gravity coated with an inorganic pigment may be used. Inorganic pigments for coating the hollow particles include calcium carbonate, talc, and titanium oxide, and those in which these are coated on the hollow particles by heat fusion or the like can be used.

  Further, the thickness of the partition walls of the hollow particles is preferably 0.05 to 3 μm. When the thickness is less than 0.05 μm, the strength of the particles is low, and the hollow particles are destroyed when printing / erasing is repeated, and cushioning properties and heat insulation properties are reduced. On the other hand, when the thickness is larger than 3 μm, the particles become hard, so the cushioning property is lowered or the heat insulating property is lowered, which is not preferable.

  Furthermore, according to the present invention, the recording layer contains a color development / decoloration control agent having a linear hydrocarbon group, a hydrogen bond group such as an amide group or a urea group, and the like together with the developer and the leuco dye. As a result, the storage stability of the color image is good, and the erasability at the time of erasing is also improved to obtain good erasability.

  Further, a protective layer containing the resin (B) in a crosslinked state can be provided on the reversible thermosensitive recording layer. As the resin used for the protective layer, the same thermosetting resin, ultraviolet curable resin, and electron beam curable resin as those used for the recording layer are used.

  As the resin (B) used in the protective layer, an ultraviolet absorbing polymer (C) having an ultraviolet absorbing group in the molecular structure is particularly preferably used.

  As the ultraviolet absorbing polymer, a monomer having an ultraviolet absorbing group and a polymer having a monomer having a crosslinkable functional group are preferably used. As the monomer having an ultraviolet absorbing group, (2 '-Hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3'-ω-butyl- A monomer having a benzotriazole skeleton such as 5′-methylphenyl) -5-chlorobenzotriazole is particularly preferably used.

  Examples of the monomer containing a functional group include 2-isopropenyl-2-oxazoline, 2-aziridinylethyl (meth) acrylate, methacrylic acid, glycidyl (meth) acrylate, hydroxylethyl (meth) acrylate, hydroxyl Examples include propyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, and tetrahydrofurfuryl (meth) acrylate, among which hydroxylethyl (meth) ) Acrylate, hydroxylpropyl (meth) acrylate and the like are particularly preferably used.

  Furthermore, in order to increase the strength of the coating film and improve heat resistance, the following monomers may be copolymerized with a copolymer of a monomer containing an ultraviolet absorbing group and a monomer containing a functional group. For example, monomers such as styrene, styrene-butadiene, styrene-isobutylene, ethylene vinyl acetate, vinyl acetate, methacrylonitrile, vinyl alcohol, vinyl pyrrolidone, acrylonitrile, methacrylonitrile; acrylic acid, methyl (meth) acrylate, ethyl (meth ) Acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, ethylhexyl (meth) acrylate, octyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) ) Acrylate, lauryl tridecyl (meth) acrylate, tridecyl (meth) acrylate, cetyl stearyl (meth) acrylate, stearyl (meth) acrylate (Meth) acrylic acid ester groups not containing functional groups such as cyclohexyl (meth) acrylate and benzyl (meth) acrylate; ethylene di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene Glycol di (meth) acrylate, decaethylene glycol di (meth) acrylate, pentacontahector ethylene glycol (meth) acrylate, butylene di (meth) acrylate, pentaerythritol tetra (meth) acrylate, trimethylolpropane tri (meth) acrylate, penta Decaethylene glycol di (meth) acrylate, phthalic acid diethylene glycol di (meth) acrylate, etc. have two or more polymerizable double bonds in one molecule Although it is mentioned from a monomer group etc., it is not particularly limited, among them, styrene, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, Particularly preferred is t-butyl (meth) acrylate. Moreover, 2 or more types can also be used together as needed.

  From the above, specific preferred examples of the polymer (C) having an ultraviolet absorption structure in a reversible thermosensitive recording medium using the compound of the present invention include 2- (2′-hydroxy-5′-methacryloxyethylphenyl). ) -2H-benzotriazole, a copolymer composed of 2-hydroxyethyl methacrylate and styrene, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2-hydroxypropyl methacrylate and methyl methacrylate However, the copolymer is not particularly limited.

Furthermore, the protective layer can contain inorganic fine particles having ultraviolet absorbing ability.
The inorganic pigment used in the recording medium using the developer which is the compound of the present invention is optional as long as it has a mean particle diameter of 0.1 μm or less. Examples of such inorganic pigments include zinc oxide, indium oxide, alumina, silica, zirconium oxide, tin oxide, cerium oxide, iron oxide, antimony oxide, barium oxide, calcium oxide, bismuth oxide, nickel oxide, magnesium oxide, chromium oxide, Metal oxides such as manganese oxide, tantalum oxide, niobium oxide, thorium oxide, hafnium oxide, molybdenum oxide, iron ferrite, nickel ferrite, cobalt ferrite, barium titanate, potassium titanate and complex oxides thereof, zinc sulfide, Metal sulfides such as barium sulfate or sulfate compounds, titanium carbide, silicon carbide, molybdenum carbide, tungsten carbide, metal carbides such as tantalum carbide, aluminum nitride, silicon nitride, boron nitride, nitride Rukoniumu, vanadium nitride, titanium nitride, niobium nitride, and metal nitrides such as gallium nitride.

Among these, a pigment having an absorption edge in a wavelength region of 400 nm or less is particularly preferable.
Such a pigment includes a pigment (A) having an absorption edge in the ultraviolet UV-A region, that is, an ultraviolet UV-A region having a wavelength of 320 to 400 nm, and an inorganic pigment having an absorption edge on the shorter wavelength side than the ultraviolet UV-A region ( B) can be classified into two groups. The inorganic pigment (A) or the inorganic pigment (B) can be used alone, but the effect becomes more remarkable by using the inorganic pigment (A) and the inorganic pigment (B) in combination. When the inorganic pigment (A) or the inorganic pigment (B) is used alone, these pigments can be contained in either the intermediate layer or the protective layer. In the case where the inorganic pigment (A) and the inorganic pigment (B) are used in combination, these pigments can be simultaneously contained in the intermediate layer or the protective layer, but the inorganic pigment (A) and the inorganic pigment (B) are included in the intermediate layer. And can be contained separately in the protective layer. In this case, by incorporating the inorganic pigment (A) in the intermediate layer and the inorganic pigment (B) in the protective layer, the effect of ultraviolet absorbing ability is more remarkably exhibited.

Specific examples of the inorganic pigment (A) include zinc sulfide, titanium oxide, indium oxide, cerium oxide, tin oxide, molybdenum oxide, zinc oxide, and gallium nitride.
Specific examples of the inorganic pigment (B) include silica, alumina, silica-alumina, antimony oxide, magnesium oxide, zirconium oxide, barium oxide, calcium oxide, strontium oxide, silicon nitride, aluminum nitride, boron nitride, and barium sulfate. Can be mentioned.

  Furthermore, inorganic / organic fillers, lubricants and the like used for this type of recording medium may be used in the protective layer of the recording medium using the developer which is the compound of the present invention.

The support of the recording medium using the developer that is the compound of the present invention is paper, resin film, PET film, synthetic paper, metal foil, glass, or a composite thereof, and the like, and can hold a heat-sensitive recording layer. Anything is acceptable. Moreover, the thing of the thickness as needed can be used individually or by bonding. That is, it is preferably 60 to 150 μm, and a support having an arbitrary thickness from about several μm to about several mm is used.
Moreover, when providing the said under layer on these support bodies, crack generation | occurrence | production prevention and generation | occurrence | production of a burr | flash are improved by providing through an contact bonding layer.
The adhesive layer can be formed by the same coating method as that for each of the above layers.

The reversible thermosensitive recording label of the present invention is one in which an adhesive layer or a pressure-sensitive adhesive layer is provided on the surface opposite to the surface of the support constituting the reversible thermosensitive recording medium described above.
This reversible thermosensitive recording label includes an adhesive layer or a pressure-sensitive adhesive layer (non-peeling paper type), and a release paper attached under the adhesive layer or pressure-sensitive adhesive layer (peeling paper type). As a material constituting the adhesive layer, a hot melt type material is usually used.
Commonly used materials can be used for the adhesive layer or the pressure-sensitive adhesive layer.
For example, urea resin, melamine resin, phenol resin, epoxy resin, vinyl acetate resin, vinyl acetate-acrylic copolymer, ethylene-vinyl acetate copolymer, acrylic resin, polyvinyl ether resin, vinyl chloride-vinyl acetate Copolymer, polystyrene resin, polyester resin, polyurethane resin, polyamide resin, chlorinated polyolefin resin, polyvinyl butyral resin, acrylic ester copolymer, methacrylic ester copolymer, natural rubber , Cyanoacrylate resins, silicon resins, and the like, but are not limited thereto.

The reversible thermosensitive recording medium of the present invention is an information display produced by combining at least a thermosensitive layer constituting the reversible thermosensitive recording medium as a reversible display unit and a member (information storage unit) having an information storage function. It can be used as a memory member.
Next, the information display storage member will be described.
The members having the information storage unit and the reversible display unit can be roughly classified into the following three items.
(1) A part of a member having an information storage function is used as a support for a reversible thermosensitive recording medium, and a thermosensitive layer is directly formed thereon.
(2) The support surface of a reversible thermosensitive recording medium having a thermosensitive layer formed on a support, which is separately formed, on a member having an information storage function.
(3) The reversible thermosensitive recording label bonded to a member having an information storage function via an adhesive layer or an adhesive layer.
In these cases (1), (2), and (3), it is necessary to set the functions of the information storage unit and the reversible display unit so that the functions of the information storage unit are set. The position can be arbitrarily selected according to the purpose, and it can be provided on the surface of the reversible thermosensitive recording medium opposite to the surface on which the thermosensitive layer is provided, between the support and the thermosensitive layer, or on the thermosensitive layer. It can also be provided in a part of.
The member having the information storage function is not particularly limited, and a general card, disk, disk cartridge, or tape cassette can be used.

  Examples of these include thick cards such as IC cards and optical cards, flexible disks, magneto-optical recording disks (MD), disk cartridges with built-in disks that can rewrite storage information such as DVD-RAM, and CD-RWs. Examples thereof include a disc that does not use a disc cartridge, a write-once disc such as a CD-R, an optical information recording medium (CD-RW) that uses a phase-change storage material, and a video tape cassette.

  An example is shown in FIGS. FIG. 3 is a diagram showing an example in which the reversible thermosensitive recording label of the present invention is pasted on an MD disk cartridge, and FIG. 4 is an example in which the reversible thermosensitive recording label of the present invention is pasted on a CD-RW. FIG. 5 is a diagram showing an example used as a display label of the video tape cassette of the present invention.

  The information display storage member having both the reversible display function and the information storage function will be described in the case of a card, for example, by displaying a part of the information stored in the information storage unit on the reversible thermosensitive recording layer. The owner or the like can confirm information by looking at the card without a special device, and the convenience is greatly improved compared to a card to which the reversible thermosensitive recording medium is not applied.

The information storage unit is not particularly limited as long as it can store necessary information. For example, magnetic recording, contact IC, non-contact IC, or optical memory is useful.
The magnetic recording layer is formed by coating the support using a commonly used metal compound such as iron oxide or barium ferrite and a resin such as vinyl chloride, urethane or nylon, or without using a resin. It forms by methods, such as vapor deposition and sputtering, using the said metal compound. Further, the reversible thermosensitive recording layer in the reversible thermosensitive recording medium used for display can also be used as a storage unit in a manner such as a barcode or a two-dimensional code.

In addition, as an example of using the reversible thermosensitive recording label of (3) above, when the reversible thermosensitive recording layer is difficult to apply as a support, such as a vinyl chloride card with a magnetic stripe, An adhesive layer or a pressure-sensitive adhesive layer can be provided on the entire surface or a part thereof.
By doing so, the convenience of this medium can be improved, such as being able to display a part of the information stored in the magnetism.
The reversible thermosensitive recording label provided with the adhesive layer or the pressure-sensitive adhesive layer is applicable not only to the above-described magnetic PVC card but also to a thick card such as an IC card or an optical card.

Further, the reversible thermosensitive recording label can be used in place of a display label on a disk cartridge having a built-in disk capable of rewriting storage information such as a flexible disk, MD, DVD-RAM and the like.
Further, in the case of a disc that does not use a disc cartridge such as a CD-RW, a reversible thermosensitive recording label can be directly attached to the disc, or a reversible thermosensitive recording layer can be provided directly on the disc. By doing so, it is possible to apply to applications such as automatically changing display contents in accordance with changes in the stored contents.

The reversible thermosensitive recording label of the present invention can also be displayed by rewriting a part of the stored information added to the CD-R by sticking the reversible thermosensitive recording label on a write-once disc such as a CD-R.
Further, it may be used as a display label for a video tape cassette.
As a method of providing a thermoreversible recording function on a thick card, a disc cartridge, and a disc, in addition to the method of applying the reversible thermosensitive recording label, a method of directly applying a reversible thermosensitive recording layer on them, There is a method of forming a reversible thermosensitive recording layer on the support and transferring the thermosensitive recording layer onto a thick card, a disc cartridge, or a disc.
When transferring, an adhesive layer such as a hot melt type or an adhesive layer may be provided on the reversible thermosensitive recording layer.
When attaching a reversible thermosensitive recording label or providing a reversible thermosensitive recording layer on a rigid object such as a thick card, disk, disk cartridge, tape cassette, etc., improve the contact with the thermal head. In order to form an image uniformly, it is preferable to provide a cushioning layer or sheet between the rigid substrate and the label or the reversible thermosensitive recording layer.

  The present invention further provides an image processing method, wherein the reversible thermosensitive recording medium, the member having the information storage unit or the label is used to form and / or erase an image by heating.

For image formation, an image recording means such as a thermal head, a laser or the like that can partially heat the medium on the image is used. For erasing the image, an image erasing means such as a hot stamp, a ceramic heater, a heat roller, hot air, a thermal head, or a laser is used.
Among these, a ceramic heater is preferably used. By using a ceramic heater, the apparatus can be miniaturized, a stable erased state can be obtained, and an image with good contrast can be obtained. FIG. 6 shows an outline of an essential part of an example of the image processing apparatus of the present invention of this type.

The set temperature of the ceramic heater is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, and even more preferably 115 ° C. or higher.
Further, by using a thermal head as the image erasing means, it is possible to further reduce the size of the entire apparatus, to reduce power consumption, and to realize a battery-driven handy type apparatus. If a single thermal head is used for both forming and erasing, the size can be further reduced.

When forming and erasing with a single thermal head, once the previous image has been erased, a new image may be formed again. The energy is changed for each image, and the previous image is erased at one time. It is also possible to use an overwrite method that forms the film.
In the overwrite method, the time required for forming and erasing is reduced, and the recording speed is increased. In the case of using a card having a reversible thermosensitive recording layer and an information storage unit, the above device includes means for reading and rewriting the memory of the information storage unit.

The present invention will be specifically described by the following examples.
Example 1 (Synthesis of phenolic compounds of the invention)
To the reaction vessel, 250 mL of toluene and 11.3 g of behenic acid were added, 7.9 g of thionyl chloride was further added, and a few drops of DMF were added, and the mixture was heated to reflux for 8 hours. The solvent and thionyl chloride were distilled off under reduced pressure using an evaporator. To the resulting acid chloride compound, 100 mL of acetone was added and stirred with ice cooling. An aqueous solution in which 3.2 g of sodium azide was dissolved was gradually added so that the temperature did not exceed 10 ° C., and the mixture was further stirred for 3 hours. The obtained reaction solution was extracted with toluene and washed, then the reaction solution was dried over magnesium sulfate, transferred to the reaction solution, and then heated at an internal temperature of 80 ° C. After confirming that the generation of nitrogen was completed and an isocyanate compound was formed, 3.3 g of p-aminophenol was added to the reaction solution, and the mixture was heated and stirred for 1 hour, then returned to room temperature, and ethanol and 20% hydrochloric acid were added. The precipitate was filtered off and washed with ethanol. After drying, a compound was obtained by recrystallizing the filtered product using 500 mL of THF. The yield was 12.6 g, and the yield was 85%. The melting point was 146 ° C. from the results of differential scanning calorimetry. The infrared absorption spectrum is shown in FIG. From the elemental analysis and infrared absorption spectrum, it was found to be the target product.

Example 2 (Example of production of reversible thermosensitive recording medium)
[Creation of thermal recording layer]
4 parts of the phenolic compound of the present invention

アクリルポリオール樹脂 ９部
（三菱レイヨン社製LR503、水酸基価：64、固形分濃度５０％溶液）
メチルエチルケトン ７０部
上記組成物をボールミルを用いて平均粒径約１μｍまで粉砕分散した。得られた分散液に２−アニリノ−３−メチル−６−ジペンチルアミノフルオラン１．５部、日本ポリウレタン社製コロネートＨＬ（アダクト型ヘキサメチレンジイソシアネート７５％酢酸エチル溶液）２部を加え、良く攪拌し感熱記録層塗布液を調製した。
上記組成の感熱記録層塗布液を、厚さ１８８μｍの白ＰＥＴにワイヤーバーを用い塗布し、１００℃２分で乾燥した後、６０℃２４時間加熱して、膜厚約１１．０μｍの記録層を設けた。

Acrylic polyol resin 9 parts (LR503 manufactured by Mitsubishi Rayon Co., Ltd., hydroxyl value: 64, solid concentration 50% solution)
70 parts of methyl ethyl ketone The above composition was pulverized and dispersed to a mean particle size of about 1 μm using a ball mill. To the obtained dispersion, 1.5 parts of 2-anilino-3-methyl-6-dipentylaminofluorane and 2 parts of Coronate HL (adduct type hexamethylene diisocyanate 75% ethyl acetate solution) manufactured by Nippon Polyurethane Co., Ltd. are added and stirred well. A thermal recording layer coating solution was prepared.
The thermal recording layer coating solution having the above composition was applied to white PET having a thickness of 188 μm using a wire bar, dried at 100 ° C. for 2 minutes, and then heated at 60 ° C. for 24 hours to form a recording layer having a thickness of about 11.0 μm. Was provided.

[Create protection layer]
40% solution of UV-absorbing polymer (UV-G300 manufactured by Nippon Shokubai Co., Ltd.) 10 parts Isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane, Coronate HX) 1.4 parts Silicone-based acrylic resin (GS-1015 manufactured by Toagosei Co., Ltd.) 0 .5 parts Methyl ethyl ketone 10 parts The above composition was well stirred to prepare a protective layer coating solution.
A protective layer coating solution having the above composition is applied onto the recording layer using a wire bar, dried at 100 ° C. for 2 minutes, and then heated at 60 ° C. for 24 hours to provide a protective layer having a thickness of about 3.5 μm. A heat-sensitive recording medium was produced.

Comparative Example 1
A reversible thermosensitive recording medium was prepared in the same manner as in Example 2 except that the following compounds were used instead of the developer used in Example 2.

The reversible thermosensitive recording medium produced as described above was tested as follows.
Test 1: Color development characteristics Printing was performed at the voltage shown in Table 1 under the condition of a pulse width of 2 msec using a thermal printing simulator manufactured by BCOM. The color density and background density were measured using a Macbeth densitometer RD914. The results are shown in Table 1.

Test 2: Decoloring characteristics Next, an image was printed under the condition of a voltage of 18 V to obtain a printed image having a length of about 15 cm. The color density of the printed part and the background density of the unprinted background part were measured. Printing was performed again while changing the voltage in increments of 0.5 V from 7.0 V to 15.0 V on the printed portion, and the portion that was most decolored thereby was determined as the erasing density, and the erasing rate was calculated by the following equation. Table 2 shows the results of the above measurement performed in an environment of a temperature of 23 ° C. and a humidity of 50%.
Erase rate (%) = (1− (erase density−background density) / (color density−background density)) × 100

Test 3: Image storability The printed image obtained in Test 2 was stored under dry conditions at 50 ° C for 24 hours. After measuring the density before and after storage in the same manner as in Test 1, the image retention rate was calculated by the following formula. The results are shown in Table 3.
Image retention (%) = (image density after storage−background density after storage) / (image density before storage−background density before storage) × 100

Example 3
[Creation of thermal recording layer]
N- (4-hydroxyphenyl) -N′-heneicosyl urea 4 parts Acrylic polyol resin 9 parts (LR503 manufactured by Mitsubishi Rayon Co., Ltd., hydroxyl value: 64, solid content concentration 50% solution)
70 parts of methyl ethyl ketone The above composition was pulverized and dispersed to a mean particle size of about 1 μm using a ball mill. To the obtained dispersion, 1.5 parts of 2-anilino-3-methyl-6-dibutylaminofluorane and 2 parts of Coronate HL (adduct type hexamethylene diisocyanate 75% ethyl acetate solution) manufactured by Nippon Polyurethane Co., Ltd. are added and stirred well. A thermal recording layer coating solution was prepared.
A thermal recording layer coating solution having the above composition was applied to white PET having a thickness of 100 μm using a wire bar, dried at 100 ° C. for 2 minutes, and then heated at 60 ° C. for 24 hours to form a recording layer having a thickness of about 11.0 μm. Was provided.

[Create protection layer]
40% solution of UV-absorbing polymer (UV-G300 manufactured by Nippon Shokubai Co., Ltd.) 10 parts Isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane, Coronate HX) 1.4 parts Silicone-based acrylic resin (GS-1015 manufactured by Toagosei Co., Ltd.) 0 .5 parts Methyl ethyl ketone 10 parts The above composition was well stirred to prepare a protective layer coating solution.
A protective layer coating solution having the above composition is applied onto the recording layer using a wire bar, dried at 100 ° C. for 2 minutes, and then heated at 60 ° C. for 24 hours to provide a protective layer having a thickness of about 3.5 μm. The reversible thermosensitive recording medium of the invention was produced.

Example 4
N- (4-hydroxyphenyl) -N′-heneicosyl urea 4 parts Acrylic polyol resin 9 parts (LR257, Mitsubishi Rayon, hydroxyl value: 107, 50% solid content solution)
70 parts of methyl ethyl ketone The above composition was pulverized and dispersed to a mean particle size of about 1 μm using a ball mill. To the obtained dispersion, 1.5 parts of 2-anilino-3-methyl-6-dibutylaminofluorane and 4 parts of Coronate HL (adduct type hexamethylene diisocyanate 75% ethyl acetate solution) manufactured by Nippon Polyurethane Co., Ltd. are added and stirred well. A thermal recording layer coating solution was prepared.

Example 5
N- (4-hydroxyphenyl) -N′-heneicosyl urea 4 parts Hydroxyl-containing polyester resin 30 parts (Dainippon Ink M8010, hydroxyl value: 24,
15% methyl ethyl ketone solution)
50 parts of methyl ethyl ketone The above composition was pulverized and dispersed to a mean particle size of about 1 μm using a ball mill. To the obtained dispersion, 1.5 parts of 2-anilino-3-methyl-6-dibutylaminofluorane and 1 part of Coronate HL (adduct type hexamethylene diisocyanate 75% ethyl acetate solution) manufactured by Nippon Polyurethane Co., Ltd. are added and stirred well. A thermal recording layer coating solution was prepared.

Example 6 (for comparison with Examples 3 to 5)
N- (4-hydroxyphenyl) -N'-heneicosylurea 4 parts PVC / vinyl acetate resin 30 parts (VYHH, Union Carbide, hydroxyl value: 0,
15% methyl ethyl ketone solution)
50 parts of methyl ethyl ketone The above composition was pulverized and dispersed to a mean particle size of about 1 μm using a ball mill. To the resulting dispersion, 1.5 parts of 2-anilino-3-methyl-6-dibutylaminofluorane was added and stirred well to prepare a thermal recording layer coating solution.

Comparative Example 2 (for comparison with Examples 3-5)
The same procedure as in Example 6 was performed except that N- (4-hydroxyphenyl) -N′-stearyl urea was used instead of N- (4-hydroxyphenyl) -N′-henecosyl urea used in Example 6. Thus, a reversible thermosensitive recording medium was produced.

Comparative Example 3 (for comparison with Examples 3-5)
The same procedure as in Example 6 was conducted except that N- (3- (p-hydroxyphenyl) propiono) -N′-stearoylhydrazide was used instead of N- (4-hydroxyphenyl) -N′-heneicosylurea. A reversible thermosensitive recording medium was produced in the same manner as in Example 6.

The reversible thermosensitive recording medium produced as described above was tested as follows.
Printing was performed at the voltage shown in Table 4 under the condition of a pulse width of 2.0 msec using a printing simulator manufactured by BCOM, and the color density and background density of the printed portion were measured using a Macbeth densitometer RD914.
The results are shown in Table 4.

Next, an image was printed under the condition of a voltage of 18 V and erased with a heat roller heated to 130 ° C. under a condition of 30 mm / second.
After repeating this printing and erasing 30 times, the state of the image portion was visually evaluated. As a result, Examples 3 to 5 were free from printing traces and could be printed in a good state, while Example 6 was Due to the surface irregularities of the recording medium, the image density does not change much even when the applied voltage is increased from when the applied voltage is low. In Comparative Examples 2 and 3, irregularities occur on the surface of the recording medium, and uniform printing is performed. It was in a state that can not be.

Example 7
[Preparation of the under layer]
Hollow particles 10 parts Particle size: 5-15μm
Wall material main component: Cross-linked acrylic polyvinyl alcohol 10% aqueous solution 150 parts Kuraray PVA618
Water 20 parts A coating solution obtained by stirring and dispersing the mixture having the above composition was applied and dried on a 100 μm white PET using a wire bar so as to have a thickness of about 15 μm.

[Preparation of thermal recording layer]
N- (4-hydroxyphenyl) -N'-heneicosyl urea 4 parts Acrylic polyol resin (LR503 manufactured by Mitsubishi Rayon Co., Ltd., solid content concentration 50% solution) 9 parts Methyl ethyl ketone 70 parts The above composition was averaged using a ball mill. The dispersion was pulverized to 1 μm. To the resulting dispersion, 1.5 parts of 2-anilino-3-methyl-6-di-n-butylaminofluorane and 2 parts of Coronate HL (Adduct type hexamethylene diisocyanate 75% ethyl acetate solution) manufactured by Nippon Polyurethane Co., Ltd. In addition, the mixture was well stirred to prepare a thermal recording layer coating solution.
A thermal recording layer coating solution having the above composition is applied onto the under layer using a wire bar, dried at 100 ° C. for 2 minutes, and then heated at 60 ° C. for 24 hours to form a recording layer having a thickness of about 11.0 μm. Provided.

[Preparation of protective layer]
40% solution of UV-absorbing polymer (UV-G300 manufactured by Nippon Shokubai Co., Ltd.) 10 parts Isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane, Coronate HX) 1.4 parts Silicone-based acrylic resin (GS-1015 manufactured by Toagosei Co., Ltd.) 0 .5 parts Methyl ethyl ketone 10 parts The above composition was well stirred to prepare a protective layer coating solution.
A protective layer coating solution having the above composition is applied onto the recording layer using a wire bar, dried at 100 ° C. for 2 minutes, and then heated at 60 ° C. for 24 hours to provide a protective layer having a thickness of about 3.5 μm. The reversible thermosensitive recording medium of the invention was produced.

Example 8
A reversible thermosensitive recording medium was obtained in the same manner as in Example 7 except that the under layer of the composition exemplified below was used instead of the under layer in Example 7.
[Preparation of under layer liquid]
Hollow particles 10 parts Average particle size: 4μm
Hollow rate: 90%
Main component of wall material: Acrylonitrile, methacrylonitrile, 10% aqueous solution of polyvinyl alcohol 150 parts PVA618 manufactured by Kuraray Co., Ltd.
20 parts of water

Example 9 (for comparison with Examples 7 and 8)
A reversible thermosensitive recording medium was produced in the same manner as in Example 7 except that the under layer produced in Example 7 was not produced.

The reversible thermosensitive recording medium produced as described above was tested as follows.
Using a printing simulator manufactured by BCOM, printing was performed at the voltage shown in Table 5 under the condition of a pulse width of 2.0 msec, and the color density and background density of the printed portion were measured using a Macbeth densitometer RD914.
The results are shown in Table 5.

Next, an image was printed under the condition of a voltage of 18 V to obtain a printed image having a length of about 15 cm. The color density of the printed part and the background density of the non-printed part were measured in the same manner. Erasing was performed by changing the voltage from 7.0 V to 15.0 V in increments of 0.5 V on the color image, and the density was measured in the same manner as the decolored density, and the erasing rate was calculated from the following formula. The above measurement was performed in an environment of 23 ° C. and 50% RH and −5 ° C. and 30% RH.
The results are shown in Table 6.
Erase rate (%) = (1− (erasing density−background density) / (coloring density−background density)) × 100

Example 10
[Creation of thermal recording layer]
N- (4-hydroxyphenyl) -N'-heneicosyl urea 4 parts Acrylic polyol resin (LR503 manufactured by Mitsubishi Rayon Co., Ltd., solid content concentration 50% solution) 9 parts Methyl ethyl ketone 70 parts The above composition was averaged using a ball mill. The dispersion was pulverized to 1 μm. To the resulting dispersion, 1.5 parts of 2-anilino-3-methyl-6-N, N, -di-n-pentylaminofluorane, Coronate HL (Adduct type hexamethylene diisocyanate 75% ethyl acetate manufactured by Nippon Polyurethane Co., Ltd.) Solution) 2 parts was added and stirred well to prepare a thermal recording layer coating solution.
A thermal recording layer coating solution having the above composition was applied to white PET having a thickness of 100 μm using a wire bar, dried at 100 ° C. for 2 minutes, and then heated at 60 ° C. for 24 hours to form a recording layer having a thickness of about 11.0 μm. Was provided.

[Create protection layer]
40% solution of UV-absorbing polymer (UV-G300 manufactured by Nippon Shokubai Co., Ltd.) 10 parts Isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane, Coronate HX) 1.4 parts Silicone-based acrylic resin (GS-1015 manufactured by Toagosei Co., Ltd.) 0 .5 parts Methyl ethyl ketone 10 parts The above composition was well stirred to prepare a protective layer coating solution.
A protective layer coating solution having the above composition is applied onto the recording layer using a wire bar, dried at 100 ° C. for 2 minutes, and then heated at 60 ° C. for 24 hours to provide a protective layer having a thickness of about 3.5 μm. The reversible thermosensitive recording medium of the invention was produced.

Example 11 (for comparison with Example 10)
Instead of 2-anilino-3-methyl-6-N, N, -di-n-pentylaminofluorane used in Example 10, 2-anilino-3-methyl-6- (N-ethyl-Np) -Tolyl) A reversible thermosensitive recording medium was prepared in the same manner as in Example 10 except that aminofluorane was used.

Comparative Example 4 (for comparison with Example 10)
Reversible in the same manner as in Example 10 except that N- (4-hydroxyphenyl) -N′-stearylurea was used instead of N- (4-hydroxyphenyl) -N′-henecosylurea used in Example 10. A heat-sensitive recording medium was produced.

Comparative Example 5 (for comparison with Example 10)
Example 10 is the same as Example 10 except that N- (3- (p-hydroxyphenylpropiono) -N′-stearoylhydrazide was used instead of N- (4-hydroxyphenyl) -N′-henecosylurea used in Example 10. Similarly, a reversible thermosensitive recording medium was produced.

The reversible thermosensitive recording medium produced as described above was tested as follows.
Printing was performed at a voltage shown in Table 7 under the condition of a pulse width of 2.0 msec using a printing simulator manufactured by BCOM, and the color density and background density of the printed portion were measured using a Macbeth densitometer RD914.
The results are shown in Table 7.

Next, an image was printed under the condition of a voltage of 18 V to obtain a printed image having a length of about 15 cm. The color density of the printed part and the background density of the non-printed part were measured in the same manner. Erasing was performed by changing the voltage from 7.0 V to 15.0 V in increments of 0.5 V on the color image, and the density was measured in the same manner as the decolored density, and the erasing rate was calculated from the following formula. Table 8 shows the environmental results of the above measurements at 23 ° C. and 50% RH and 5 ° C. and 30% RH.
Erase rate (%) = (1− (erasing density−background density) / (coloring density−background density)) × 100

It is a figure which shows the color development and decoloring characteristic of the reversible thermosensitive coloring composition using this invention. It is an infrared absorption spectrum of the phenol compound of this invention. It is a figure which shows the example which stuck the reversible thermosensitive recording label on the disk cartridge of MD. It is a figure which shows the example which stuck the reversible thermosensitive recording label on CD-RW. It is a figure which shows the example used as a display label of a videotape cassette. It is a figure which shows the example of the image processing apparatus of this invention.

Explanation of symbols

34 Magnetic head 38 Ceramic heater 40 Transport roller 47 Transport roller 53 Thermal head

Claims (21)

N-heneicosyl-N ′-(4-hydroxyphenyl) urea which is a novel phenol compound represented by the following formula (1).

A reversible sensation that can form a relatively colored state and a decolored state depending on the heating temperature and / or the cooling rate after heating, using an electron donating coloring compound and an electron accepting compound on the support. A reversible thermosensitive recording medium having a thermal recording layer, wherein the electron-accepting compound contains at least N-heneicosyl-N ′-(4-hydroxyphenyl) urea. The reversible thermosensitive recording medium according to claim 2, wherein the recording layer contains a resin (A) in a crosslinked state. The reversible thermosensitive recording medium according to claim 3, wherein the resin (A) contained in the recording layer has a hydroxyl value of 70 (KOHmg / g) or more. The reversible thermosensitive recording medium according to claim 3 or 4, wherein the resin (A) contained in the recording layer is an acrylic polyol resin. 6. The reversible thermosensitive recording medium according to claim 3, wherein the resin (A) contained in the recording layer is crosslinked with an isocyanate compound. The reversible thermosensitive recording medium according to any one of claims 2 to 6, wherein an under layer containing hollow particles is provided between the support and the recording layer. The reversible thermosensitive recording medium according to claim 7, wherein the number average particle diameter of the hollow particles is 0.2 µm or more and 50 µm or less. 9. The reversible thermosensitive recording medium according to claim 7, wherein a volumetric hollow ratio of the hollow particles is 70% or more and 95% or less. The reversible thermosensitive recording medium according to any one of claims 7 to 9, wherein the hollow particles are coated with a substance selected from the group consisting of calcium carbonate, talc and titanium oxide. The reversible thermosensitive recording medium according to any one of claims 7 to 10, wherein a thickness of the partition walls of the hollow particles is 0.05 µm or more and 3 µm or less. The 2-anilino-3-methyl-6-N, N, -di-n-pentylaminofluorane is used as the electron-donating color developing compound. Reversible thermosensitive recording medium. 13. The reversible according to claim 2, further comprising a protective layer on the reversible thermosensitive recording layer, wherein the protective layer contains at least a resin (B) in a crosslinked state. Sexual thermal recording medium. The reversible feeling according to any one of claims 2 to 13, further comprising a protective layer on the reversible thermosensitive recording layer, wherein the protective layer contains an ultraviolet absorbing polymer (C). Thermal recording medium. 15. The reversible thermosensitive recording medium according to claim 2, further comprising a protective layer on the reversible thermosensitive recording layer, wherein the protective layer contains inorganic fine particles having ultraviolet absorbing ability. 16. The reversible thermosensitive recording medium according to claim 2, further comprising an information storage unit. The reversible thermosensitive recording medium according to any one of claims 2 to 16, wherein an adhesive layer or a pressure-sensitive adhesive layer is provided on the surface. An image processing method comprising forming and / or erasing an image using the reversible thermosensitive recording medium according to claim 2. The image processing method according to claim 18, wherein an image is formed on the reversible thermosensitive recording medium using a thermal head. 19. The image processing method according to claim 18, wherein the reversible image formed on the reversible thermosensitive recording medium is erased using a thermal head or a ceramic heater. An image processing apparatus that forms and / or erases an image using the image processing method according to claim 18.

Images