JP2006051616A - Developer for thermal recording material and thermal recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer for a thermal recording material which shows higher than the same level of excellent color developing sensitivity and resistance to water, oil and light as the counterpart using bisphenol A as a raw material, and a method for manufacturing this developer. <P>SOLUTION: This developer for a thermal recording material is composed of a chemical compound shown in formula [1] (wherein, R<SB>1</SB>is one selected from the group consisting of hydrogen, a 1-4C alkyl group, a 5-7C cycloalkyl group, a phenyl group, an aralkyl group, an alkoxy group and a halogen atom; n is a integer of 1 to 4; R<SB>2</SB>is one selected from the group consisting of hydrogen, hydroxyl, a 1-4C alkyl group, a 5-7C cycloalkyl group, a phenyl group, an aralkyl group, an alkoxy group and a halogen atom; and m is an integer of 1 to 4). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developer for a heat-sensitive recording material, a production method thereof, a heat-sensitive recording material containing the developer for the heat-sensitive recording material, and a heat-sensitive recording material using the same.

  Thermal recording materials are mainly used in facsimiles, measuring devices, medical devices, and the like, and recently, they are used in bar code labels and register receipts used in POS systems and the like, and the amount of use is increasing. With the wide variety of applications, various properties such as water resistance, oil resistance, and light resistance are required for heat-sensitive recording materials.

  The heat-sensitive recording material is generally produced by applying a heat-sensitive recording material containing a leuco dye as a color forming precursor and a developer as an acidic compound as basic components on a support. As the developer, a phenol compound has been used for a long time, and a bisphenol compound represented by bisphenol A is most commonly used (for example, see Patent Documents 1 and 2). However, bisphenol A has recently been reported as an environmental hormone substance that adversely affects reproductive functions, and the demand for an alternative compound is very high.

  In order to solve this problem, acidic compounds having various phenol skeletons have been studied, but a color developer that is excellent in water resistance, oil resistance, light resistance and the like in place of bisphenol A has not yet been obtained. Is the current situation.

JP-A-56-015394 JP-A-57-151394

  The present invention relates to a developer for a heat-sensitive recording material excellent in color development sensitivity, water resistance, oil resistance, and light resistance, equivalent to or higher than that using bisphenol A as a raw material, and a method for producing the same, and the heat-sensitive recording material The present invention provides a heat-sensitive recording material containing a developer and a heat-sensitive recording material using the same.

上記一般式［１］中、Ｒ_１は、水素、炭素数１〜４のアルキル基、炭素数５〜７のシクロアルキル基、置換又は無置換フェニル基、置換又は無置換アラルキル基、アルコキシ基、及び、ハロゲン原子から選ばれるものである。ｎは１〜４の整数を示し、ｎが２〜４のとき、１分子内に存在するＲ_１同士は同じであっても異なっていてもよい。
Ｒ_２は、水素、水酸基、炭素数１〜４のアルキル基、炭素数５〜７のシクロアルキル基、置換又は無置換フェニル基、置換又は無置換アラルキル基、アルコキシ基、及び、ハロゲン原子から選ばれるものである。ｍは１〜４の整数を示し、ｍが２〜４のとき、１分子内に存在するＲ_２同士は同じであっても異なっていてもよい。
（２） 上記一般式［１］で示される化合物中、Ｒ_１が水素、メチル基、及び、イソプロピル基から選ばれるものであり、ｎ＝１〜３である上記（１）に記載の感熱記録材料用顕色剤。
（３） 上記一般式［１］で示される化合物中、Ｒ_２が水素、水酸基、及び、メチル基から選ばれるものであり、ｍ＝１〜３である上記（１）又は（２）に記載の感熱記録材料用顕色剤。
（４） 上記一般式［１］で示される化合物を、顕色剤全体に対して５０重量％以上含有することを特徴とする感熱記録材料用顕色剤。
（５） 上記（１）ないし（４）のいずれかに記載の感熱記録材料用顕色剤の製造方法であって、
（ａ） 下記一般式［２］で示されるシクロヘキサノン化合物と、下記一般式［３］で示されるフェノール化合物とを、酸性触媒の存在下で反応させて、下記一般式［４］で示されるシクロヘキシリデンビスフェノール化合物を合成する工程、及び、
（ｂ）上記シクロヘキシリデンビスフェノール化合物とアセチル化剤を反応させて、上記一般式［１］で示される化合物を合成する工程、
を有することを特徴とする、感熱記録材料用顕色剤の製造方法。

上記一般式［２］および［４］中、Ｒ_１は、水素、炭素数１〜４のアルキル基、炭素数５〜７のシクロアルキル基、置換又は無置換フェニル基、置換又は無置換アラルキル基、アルコキシ基、及び、ハロゲン原子から選ばれるものである。ｎは１〜４の整数を示し、ｎが２〜４のとき、１分子内に存在するＲ_１同士は同じであっても異なっていてもよい。
上記一般式［３］および［４］中、Ｒ_２は、水素、水酸基、炭素数１〜４のアルキル基、炭素数５〜７のシクロアルキル基、置換又は無置換フェニル基、置換又は無置換アラルキル基、アルコキシ基、及び、ハロゲン原子から選ばれるものである。ｍは１〜４の整数を示し、ｍが２〜４のとき、１分子内に存在するＲ_２同士は同じであっても異なっていてもよい。
（６） 上記（１）ないし（４）のいずれかに記載の感熱記録材料用顕色剤と、ロイコ染料とを含有することを特徴とする感熱記録材料。
（７） 上記（６）に記載の感熱記録材料を支持体上に塗布してなることを特徴とする感熱記録材。 Such an object is achieved by the following present inventions (1) to (7).
(1) A developer for a heat-sensitive recording material comprising a compound represented by the following general formula [1].

In the general formula [1], R ₁ is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, an alkoxy group, And a halogen atom. n represents an integer of 1 to 4, and when n is 2 to 4, R ₁ existing in one molecule may be the same or different.
R ₂ is selected from hydrogen, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, an alkoxy group, and a halogen atom. It is what m represents an integer of 1 to 4, and when m is 2 to 4, R ₂ existing in one molecule may be the same or different.
(2) In the compound represented by the general formula [1], R ₁ is selected from hydrogen, a methyl group, and an isopropyl group, and n = 1 to 3, and the thermal recording according to the above (1). Developer for materials.
(3) In the compound represented by the above general formula [1], R ₂ is selected from hydrogen, a hydroxyl group, and a methyl group, and m = 1 to 3 as described in (1) or (2) above Developer for heat-sensitive recording materials.
(4) A developer for a heat-sensitive recording material comprising the compound represented by the general formula [1] in an amount of 50% by weight or more based on the whole developer.
(5) A method for producing a developer for a heat-sensitive recording material according to any one of (1) to (4) above,
(A) A cyclohexanone compound represented by the following general formula [2] and a phenol compound represented by the following general formula [3] are reacted in the presence of an acidic catalyst to produce a cyclohexene represented by the following general formula [4]. Synthesizing a silidene bisphenol compound, and
(B) a step of reacting the cyclohexylidenebisphenol compound with an acetylating agent to synthesize a compound represented by the general formula [1],
A method for producing a developer for a heat-sensitive recording material, comprising:

In the general formulas [2] and [4], R ₁ is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted aralkyl group. , An alkoxy group, and a halogen atom. n represents an integer of 1 to 4, and when n is 2 to 4, R ₁ existing in one molecule may be the same or different.
In the general formulas [3] and [4], R ₂ represents hydrogen, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted group. It is selected from an aralkyl group, an alkoxy group, and a halogen atom. m represents an integer of 1 to 4, and when m is 2 to 4, R ₂ existing in one molecule may be the same or different.
(6) A heat-sensitive recording material comprising the developer for a heat-sensitive recording material according to any one of (1) to (4) above and a leuco dye.
(7) A heat-sensitive recording material obtained by coating the heat-sensitive recording material according to (6) on a support.

The present invention relates to a developer for a heat-sensitive recording material comprising the compound represented by the general formula [1], a method for producing the same, and a heat-sensitive recording material containing the developer for the heat-sensitive recording material. And a heat-sensitive recording material using the same.
The developer and the heat-sensitive recording material for the heat-sensitive recording material of the present invention do not use bisphenol A, which has been pointed out as an environmental problem, as a raw material, and have color development sensitivity equal to or higher than that using bisphenol A, water resistance, A heat-sensitive recording material having oil resistance and light resistance can be produced.

Hereinafter, the developer for the heat-sensitive recording material of the present invention, a method for producing the same, the heat-sensitive recording material containing the developer for the heat-sensitive recording material, and the heat-sensitive recording material using the same will be described.
First, the developer for the heat-sensitive recording material of the present invention will be described.
The developer for a heat-sensitive recording material of the present invention (hereinafter sometimes simply referred to as “developer”) is composed of a compound represented by the following general formula [1].

上記一般式［１］中、Ｒ_１は、水素、炭素数１〜４のアルキル基、炭素数５〜７のシクロアルキル基、置換又は無置換フェニル基、置換又は無置換アラルキル基、アルコキシ基、及び、ハロゲン原子から選ばれるものである。
ここで、炭素数１〜４のアルキル基としては、例えば、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｓｅｃ−ブチル基、ｔｅｒｔ−ブチル基などが挙げられる。置換又は無置換フェニル基としては、例えば、フェニル基、トルイル基、キシリル基、トリメチルフェニル基などのアリール基が挙げられる。
置換又は無置換アラルキル基としては、例えば、ベンジル基などが挙げられる。アルコキシ基としては、例えば、メトキシ基、エトキシ基などが挙げられる。ハロゲン原子としては、フッ素原子、塩素原子、臭素原子、ヨウ素原子である。

In the general formula [1], R ₁ is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, an alkoxy group, And a halogen atom.
Here, examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. It is done. Examples of the substituted or unsubstituted phenyl group include aryl groups such as phenyl group, toluyl group, xylyl group, and trimethylphenyl group.
Examples of the substituted or unsubstituted aralkyl group include a benzyl group. Examples of the alkoxy group include a methoxy group and an ethoxy group. The halogen atom is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

In the general formula [1], n represents an integer of 1 to 4, and the melting point of the resulting compound can be controlled by adjusting the value of n. Further, when n is 2 to 4, R ₁ together present in one molecule may be different even in the same.

In the compound represented by the general formula [1], R ₁ is preferably selected from hydrogen, a methyl group, and an isopropyl group. Thereby, the compound represented by the general formula [1] can have a high melting point. N is preferably 1 to 3. By appropriately selecting the number of n from this range, it is possible to obtain a melting point suitable for use as a developer, and to improve the storage stability.

In the general formula [1], R ₂ represents hydrogen, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, or alkoxy. It is selected from a group and a halogen atom.
Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. Examples of the substituted or unsubstituted phenyl group include aryl groups such as phenyl group, toluyl group, xylyl group, and trimethylphenyl group.
Examples of the substituted or unsubstituted aralkyl group include a benzyl group. Examples of the alkoxy group include a methoxy group and an ethoxy group. The halogen atom is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

In the general formula [1], m represents an integer of 1 to 4, and the melting point and acidity of the resulting compound can be controlled by adjusting the value of m. Moreover, when m is 2-4, R ₂ existing in one molecule may be the same or different.

In the compound represented by the general formula [1], R ₂ is preferably selected from hydrogen, a hydroxyl group, and a methyl group. Thereby, since it can be set as high acidity, color developability can be made favorable. M is preferably 1 to 3. Thereby, since it can be set as high acidity, color developability can be made favorable.

The developer of the present invention comprises a compound represented by the above general formula [1]. Moreover, what contains this compound as a part of developer is also contained in this invention. In this case, the ratio of the compound represented by the general formula [1] with respect to the whole developer is appropriately determined according to the required characteristics of the developer, and is not particularly limited, but is 50% by weight. The above is preferable. Thereby, it is excellent in thermal responsiveness, and the storage stability of the thermosensitive recording material using the same can be improved.
Of these, when the developer substance other than the compound represented by the general formula [1] is a cyclohexylidene bisphenol compound represented by the general formula [4] which is a starting material of this compound, the general formula [1] Is preferable for the simplification of the production process, particularly the purification process.

Next, a method for producing the developer for the heat-sensitive recording material of the present invention (hereinafter sometimes simply referred to as “manufacturing method”) will be described. The production method of the present invention comprises:
(A) A cyclohexanone compound represented by the following general formula [2] and a phenol compound represented by the following general formula [3] are reacted in the presence of an acidic catalyst to produce a cyclohexene represented by the following general formula [4]. Synthesizing a silidene bisphenol compound, and
(B) a step of reacting the cyclohexylidenebisphenol compound with an acetylating agent to synthesize a compound represented by the general formula [1],
It is characterized by having.

In the general formulas [2] and [4], R ₁ is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted aralkyl group. , An alkoxy group, and a halogen atom. Examples of these R ₁ include the same ones as described in the general formula [1], but are preferably selected from hydrogen, a methyl group, and an isopropyl group.
Further, n represents an integer of 1 to 4, when n is 2 to 4, R ₁ together present in one molecule may be different even in the same. n is preferably 1 to 3.

  As the cyclohexanone compound represented by the general formula [2], for example, cyclohexanone, 2-methylcyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 4-isopropylcyclohexanone, 3,3,5-trimethylcyclohexanone and the like are preferable. Can be used.

In the general formulas [3] and [4], R ₂ represents hydrogen, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted group. It is selected from an aralkyl group, an alkoxy group, and a halogen atom. Examples of these R ₂ include the same as those described in the general formula [1], but are preferably selected from hydrogen, a hydroxyl group, and a methyl group.
M represents an integer of 1 to 4, and when m is 2 to 4, R ₂ existing in one molecule may be the same or different. m is preferably 1 to 3.

  As the phenol compound represented by the general formula [3], for example, phenol, cresol, xylenol, resorcin, pyrogallol and the like can be suitably used.

First, the step (a) will be described.
In step (a), a cyclohexanone compound and a phenol compound are reacted in the presence of an acidic catalyst to synthesize a cyclohexylidene bisphenol compound.

  In the step (a), the reaction molar ratio (H / P) when the cyclohexanone compound (H) represented by the general formula [2] is reacted with the phenol compound (P) represented by the general formula [3]. ) Is not particularly limited, but is preferably 0.125 to 0.5. More preferably, it is 0.25-0.4. Thereby, it is possible to achieve both the properties of the developer obtained finally and the economy by efficiently performing the intended reaction.

The acidic catalyst used in the step (a) is not particularly limited, and examples thereof include organic carboxylic acids such as oxalic acid, acetic acid and trifluoroacetic acid, inorganic acids such as hydrochloric acid and sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid, and trifluoro. Organic sulfonic acids such as romethanesulfonic acid, organic phosphonic acids, or heteropolyacids such as phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, and silicotungstic acid can be used.
Although the usage-amount of an acidic catalyst is not specifically limited, It is preferable to use 0.1 times equivalent or more with respect to the phenolic compound used from the point of reaction control and reaction rate.

  In the step (a), a reaction solvent may be used as necessary. The reaction solvent is not particularly limited, and any cyclohexanone compound and phenol compound as raw materials can be dissolved, and any solvent that does not contribute to this reaction can be used without particular limitation.

Next, the step (b) will be described.
In step (b), the cyclohexylidene bisphenol compound obtained in step (a) is reacted with an acetylating agent to synthesize the compound represented by general formula [1].

  In the step (b), a commonly used acetylating agent such as acetyl chloride or acetic anhydride can be used. However, since acetyl chloride is highly reactive and easily decomposes with water, it must be used with care. On the other hand, acetic anhydride is preferable because it is easy to handle because of its slow decomposition rate with water. In addition, this acetylation reaction can be carried out using a dehydrating agent such as sulfuric acid or zinc chloride, or a base such as pyridine as a reaction aid.

  In the step (b), the reaction molar ratio of the cyclohexylidene bisphenol compound and the acetylating agent is not particularly limited, but the acetylating agent is 0.3 to 1.7 with respect to 1 equivalent of the cyclohexylidene bisphenol compound. Equivalent (preferably 0.4 to 1.2 equivalent). Thereby, the target reaction can be performed efficiently, and it is possible to achieve both the properties of the finally obtained developer and the economical efficiency.

The reaction product thus obtained contains the compound represented by the general formula [1]. From this reaction product, the target compound represented by the general formula [1] is crystallized by an ordinary method. Various purification operations such as precipitation, filtration, and recrystallization can be appropriately performed. Thereby, a compound with few impurities can be obtained.

Next, the manufacturing method of this invention is demonstrated according to reaction order.
In a reaction vessel equipped with a stirrer, a condenser (condenser), a heating device, a thermometer, etc., a phenol compound and an acidic catalyst are charged and mixed. Next, the cyclohexanone compound is sequentially added thereto. Although reaction temperature is not specifically limited, About room temperature-about 80 degreeC is preferable. The time for sequential addition is not particularly limited, but is preferably 0.5 to 3 hours from the viewpoint of reaction control, reaction rate, and purity of the target compound. Thereafter, the reaction is further carried out for 1 to 8 hours. Then, the target substance can be obtained by neutralizing the acidic catalyst used for the reaction with a basic substance and removing water, neutralized salts, unreacted raw materials, and the like. The cyclohexylidene bisphenol compound thus obtained can be recrystallized using an appropriate solvent in order to further improve the purity.

  The cyclohexylidene bisphenol compound obtained by the above method is dissolved in a reaction aid such as pyridine, and an acetylating agent, preferably acetic anhydride, is added thereto to carry out hydroxyl group acetylation reaction. The reaction temperature is not particularly limited. Heating may be performed for the purpose of accelerating the reaction, but it is preferable to set the temperature to about room temperature to 60 ° C. The reaction time is usually 1 to 12 hours. The product containing the compound represented by the general formula [1] obtained by the reaction is usually obtained by dropping the reaction solution into a large amount of water and filtering the precipitated crystals. Then, it is washed with water until the pyridine odor disappears, and then dried. For the purpose of improving the purity, recrystallization can also be performed using an appropriate solvent, and this can be dried to obtain the desired compound represented by the general formula [1].

Next, the heat-sensitive recording material of the present invention will be described.
The heat-sensitive recording material of the present invention is characterized by containing the developer of the present invention or the developer obtained by the production method of the present invention and a leuco dye.

  The leuco dye used in the heat-sensitive recording material of the present invention is not particularly limited. For example, triphenylmethane, fluorane, phenothiazine, auramine, and spiro leuco dyes can be used.

  Examples of triphenylmethane-based leuco dyes include triphenylmethane.

  Examples of the fluorane leuco dye include 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone, CVL), p, p'-benzylidenebis (N, N '-Dimethylaniline (leucomalachite green), 3-diethylamino-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3- (N-methyl-p-toluidino)- 6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3- (N-methylcyclohexyl-N -Methylamino) -6-methyl-7-anilinofluorane, 2-anilino-3-methyl-6-dibutylfluorane, 3 Diethylamino-7- (o-chloroanilino) fluorane, 3-diethylamino-7- (m-trifluoromethylanilino) fluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6-methylflurane Oran, 3-cyclohexylamino-6-chlorofluorane, 3- (N-isoamyl-N-ethylamino) -6-methyl-7-anilinofluorane, and the like.

  Examples of phenothiazine-based leuco dyes include benzoyl leucomethylene blue and p-nitrobenzoyl leucomethylene blue.

  Examples of the olamine leuco dye include 4,4′-bis (dimethylaminophenyl) benzhydrylbenzyl ether, N-chlorophenyl leucoolamine, N-2,4,5-trichlorophenyl leucoolamine. Etc.

  Examples of spiro leuco dyes include 3-methylspirodinaphthopyrans, 3-ethylspirodinaphthopyrans, benzo-β-naphthopiropyrans, and the like.

  These leuco dyes can be appropriately selected depending on the hue and color developability, and can be used alone or as a mixture of two or more as required.

  In addition to the above-mentioned developer and leuco dye, various additives can be added to the heat-sensitive recording material of the present invention as necessary. Examples of the additive mainly include a binder, a pigment, and a sensitizer.

  The binder is not particularly limited. For example, polyvinyl alcohol, starch, starch derivatives, hydroxyethyl cellulose, methyl cellulose, sodium polyacrylate, polyvinyl pyrrolidone, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, etc. An aqueous emulsion such as a water-soluble polymer, styrene-butadiene latex, styrene-acrylic ester emulsion, or polyvinyl acetate emulsion can be added, whereby the developer composition can be strongly adhered to the support.

  The pigment is not particularly limited, and examples thereof include calcium carbonate, talc, kaolin, calcined kaolin, and aluminum hydroxide.

  The sensitizer is not particularly limited, and examples thereof include stearic acid amide, palmitic acid amide, oleic acid amide, lauric acid amide, ethylene bisstearamide, methylol stearoamide, and the like.

  In addition, generally known waxes, wax-like substances, organic fillers, inorganic fillers, and the like can be added to improve head matching properties, writing properties, whitening of the background, and the like.

  In the heat-sensitive recording material of the present invention, the blending amount of the developer of the present invention, the leuco dye, etc. is not particularly limited. Usually, the developer is 1 to 30 weights with respect to the entire solid content in the heat-sensitive recording material. %, Leuco dye 1 to 15% by weight, and binder 1 to 30% by weight.

The method for preparing the heat-sensitive recording material of the present invention is not particularly limited. For example, in addition to a developer containing a compound represented by the above general formula [1], a leuco dye, and an additive such as a binder, It can be prepared as a solution dissolved in or a mixed solution dispersed. When preparing in such a form, this can be normally apply | coated and used for a support body.
In addition, for example, a leuco dye can be mixed with a binder solution, and a developer can be mixed with the binder solution. When using in such a form, the method of applying each mixed solution to the support after mixing the mixed solutions, the method of applying each mixed solution to the same surface of the same support sequentially, or the same mixed solution There is a method of coating the front and back surfaces of the support separately, and the method is not particularly limited.

Next, the heat-sensitive recording material of the present invention will be described.
The heat-sensitive recording material of the present invention is obtained by coating the heat-sensitive recording material of the present invention on a support.
Although it does not specifically limit as a support body here, Generally paper, a synthetic paper, a synthetic resin film, a metal laminate film, etc. can be used. The support can be selected in a timely manner depending on the application and purpose for which the thermosensitive recording material is used. The heat-sensitive recording material of the present invention is obtained by applying the heat-sensitive recording material of the present invention to these supports by, for example, the above-mentioned method, performing a smoothing treatment or the like as necessary, and drying it. It is what

  Hereinafter, the present invention will be described in detail with reference to examples. Here, “parts” all represent “parts by weight”, and “%” all represent “% by weight”.

1. Preparation of developer for heat-sensitive recording material 1.1 Synthesis of cyclohexylidenebisphenol compound <Synthesis Example 1>
300 parts of phenol (P) and 37.5 parts of 35% hydrochloric acid were added to a reaction vessel equipped with a stirrer, a condenser, a heating device, and a thermometer, and heated to 50 ° C. While maintaining this temperature, 78.2 parts of cyclohexanone (H) (reaction molar ratio H / P = 0.25) was sequentially added over 2 hours, and further reacted at 50 ° C. for 6 hours. did. The hydrochloric acid used in the reaction was neutralized by adding 57.5 parts of 25% aqueous sodium hydroxide solution, washed with hot water to remove unreacted substances as much as possible, and then dried in a vacuum at 120 ° C. using a dryer. To obtain 53.6 parts of a cyclohexylidenebisphenol compound.

<Synthesis Example 2>
300 parts of phenol (P) and 37.5 parts of 35% hydrochloric acid were added to a reaction vessel equipped with a stirrer, a condenser, a heating device, and a thermometer, and heated to 50 ° C. While maintaining this temperature, 89.4 parts of 4-methylcyclohexanone (H) (reaction molar ratio H / P = 0.25) were sequentially added over 2 hours, and further reacted at 50 ° C. for 6 hours. Crystals precipitated. The hydrochloric acid used in the reaction was neutralized by adding 57.5 parts of 25% aqueous sodium hydroxide solution, washed with hot water to remove unreacted substances as much as possible, and then dried in a vacuum at 120 ° C. using a dryer. To obtain 52.9 parts of a cyclohexylidenebisphenol compound.

1.2 Synthesis of developer <Example 1>
To 26.8 parts (0.1 mol) of the cyclohexylidenebisphenol compound obtained in Synthesis Example 1, 100 parts of pyridine was added and dissolved. Acetic anhydride 6.1 parts (0.06 mol, equivalent ratio 0.6) was added thereto, and then the temperature of the solution was heated to 60 ° C. and reacted for 6 hours.
The reaction solution was dropped into 1000 parts of water over 1 hour, and then the precipitated crystals were filtered and washed with water until the pyridine odor disappeared.
As a result of analyzing the obtained reaction product using reverse phase chromatography, 53% of the unreacted product was obtained and 43% of the compound obtained in Synthesis Example 1 was acetylated only on one side of the hydroxyl group. The amount of acetylated hydroxyl group was 4%.
This crude product was recrystallized from isopropyl alcohol, and unreacted raw materials were taken out as crystals. Next, isopropyl alcohol was distilled off from the remaining solution to obtain crystals of the reaction product.
As a result of analyzing the obtained reaction product (purified product) using reverse phase chromatography, 15% of the unreacted product was obtained, and only one side of the hydroxyl group in the compound obtained in Synthesis Example 1 was acetylated ( 82% of the compound represented by the general formula [1] and 3% of which both hydroxyl groups were acetylated. This was used as a raw material for the liquid B of the heat-sensitive recording material. This was used as a raw material for the liquid B of the heat-sensitive recording material.

<Example 2>
Instead of the cyclohexylidene bisphenol of Example 1, 28.2 parts of the cyclohexylidene bisphenol compound obtained in Synthesis Example 2 (equivalent ratio 0.6) was reacted in the same manner. Thereafter, washing with water was carried out in the same manner as in Example 1, and analysis was conducted using reverse phase chromatography. As a result, 49% of the unreacted product and 44% of the hydroxyl group in the compound obtained in Synthesis Example 2 were acetylated. %, And 7% was obtained by acetylating both hydroxyl groups.
The reaction product (purified product) obtained after recrystallization with isopropyl alcohol was analyzed using reverse phase chromatography. As a result, the unreacted product was 12%, and one side of the hydroxyl group in the compound obtained in Synthesis Example 2 was obtained. Only 85% was acetylated (compound represented by the general formula [1]), and 3% was acetylated on both hydroxyl groups. This was used as a raw material for the liquid B of the heat-sensitive recording material.

3. Preparation of thermosensitive recording material <Example 11>
The following raw materials and blends were separately wet-ground with a ball mill for 24 hours to prepare dispersion liquid mixture A and liquid B.

(3.1) Liquid A, crystal violet lactone 10 parts, stearic acid amide 20 parts, 10% by weight polyvinyl alcohol aqueous solution (“# 105” manufactured by Kuraray Co., Ltd.) 60 parts, calcium carbonate 50 parts, water 150 parts

(3.2) Liquid B • Reaction product (purified product) obtained in Example 1 10 parts · 10 wt% polyvinyl alcohol aqueous solution (“# 105” manufactured by Kuraray) 20 parts · Calcium carbonate 20 parts · Water 50 Part

The A and B liquids obtained above were blended in the following proportions to prepare a heat sensitive recording material.
(3.3) Thermosensitive recording material / A liquid 20 parts / B liquid 20 parts / 10 wt% polyvinyl alcohol aqueous solution (“# 105” manufactured by Kuraray Co., Ltd.) 15 parts

<Example 12>
In Example 11, the reaction product (purified product) obtained in Example 2 was used instead of the reaction product (purified product) obtained in Example 1, and the same procedure as in Example 11 was performed. A heat-sensitive recording material was obtained.

<Example 13>
In Example 11, instead of the reaction product (purified product) obtained in Example 1, the reaction product (purified product) obtained in Example 2 and the compound obtained in Synthesis Example 2 were combined with 70 : A heat-sensitive recording material was obtained in the same manner as in Example 11 except that the ratio was 30. In this case, the ratio of the compound represented by the general formula [1] is 59.5% by weight.

<Example 14>
In Example 11, instead of the reaction product (purified product) obtained in Example 1, the compound obtained in Example 2 and the compound obtained in Synthesis Example 2 were used in a ratio of 50:50. Except that, a heat-sensitive recording material was obtained in the same manner as in Example 11. In this case, the ratio of the compound represented by the general formula [1] is 42.5% by weight.

<Comparative Example 11>
In Example 11, a heat-sensitive recording material was obtained in the same manner as in Example 11 except that bisphenol A was used in place of the compound obtained in Example 1.

3. Preparation of heat-sensitive recording material The heat-sensitive recording materials obtained in Examples 11 to 14 and Comparative Example 11 were applied to fine paper so that the coating amount after drying was 7 to 9 g / m ² , dried, and heat-sensitive. A recording material was prepared.

  The items described in Table 1 were evaluated for the heat-sensitive recording material obtained above. Table 1 shows the evaluation results obtained in Examples 11 to 14 and Comparative Example 11.

(Measuring method)
(1) Content of the compound represented by the above general formula [1]: The reaction product of the cyclohexylidene bisphenol and the acetylating agent obtained in Examples 1 and 2 is represented by the general formula [ The content of the compound represented by 1] was measured. Here, “the content of the compound represented by the general formula [1]” means that the unreacted product, the compound represented by the general formula [1], and the phenolic hydroxyl group obtained by reverse phase chromatography are both It is the content calculated from the area ratio corresponding to each of the reacted compounds. The measured values are as described in the description of Examples 1 and 2.
The measurement conditions of reverse phase chromatography are as follows. When measured under these conditions, the retention time of the compound represented by the general formula [1] is about 8 to 9 minutes.
・ Column: manufactured by TOSOH ・ “TSK-GEL ODS-120T”
-Column temperature: 40 ° C
-Mobile phase: acetonitrile / water = 7/3 (volume ratio)
・ Flow rate: 0.5 ml / min,
・ Detection wavelength 280nm

(2) Color developability: Two glass plates with a thickness of 1.2 mm were placed on a 200 ° C. heating plate and heated to this temperature. Next, the heat-sensitive recording material obtained above was sandwiched between the glass plates and held for 3 seconds to develop color. This was observed with the naked eye, and a color that was the same color as in Comparative Example 11 was marked as ◯.

(3) Water resistance: A colored thermal recording material sample was prepared in the same manner as in the evaluation of color development. This was immersed in pure water at 25 ° C. for 2 hours and then air-dried, and changes in the color image were observed with the naked eye. A sample in which no decrease in density was observed was indicated by ◎, and a sample in which the concentration decrease was not significant was indicated by ◯.

(4) Oil resistance: A colored thermal recording material sample was prepared in the same manner as in the evaluation of color development. This was sandwiched between PVC wrap films and allowed to stand at 40 ° C. for 24 hours under a load of 200 g / cm ² from the upper side of the color development surface, and the change in the color development image was observed with the naked eye. A sample in which no decrease in density was observed was indicated by ◎, and a sample in which the concentration decrease was not significant was indicated by ◯.

(5) Light resistance: A heat-sensitive recording material sample was developed in the same manner as in the evaluation of color development. This was irradiated with an ultraviolet fade meter (FAL-5 manufactured by Suga Test Instruments Co., Ltd.) for 24 hours, and the change in the color image was observed with the naked eye. The case where almost no fading or discoloration was observed was marked with ◎, and the case where discoloration or fading was slightly recognized was marked with ◯.

  The reaction products (purified products) obtained in Examples 1 and 2 are mainly composed of the compound represented by the above general formula [1], which is the developer of the present invention, and the developer of the present invention. It is an agent. Examples 11 to 14 are heat-sensitive recording materials of the present invention using a reaction product (purified product) containing the above compound as a developer, compared with Comparative Example 11 in which bisphenol A was blended as a developer. In addition, in any of water resistance, oil resistance, and light resistance, it was possible to obtain a heat-sensitive recording material having characteristics equal to or higher than those.

  The developer for heat-sensitive recording material and the heat-sensitive recording material of the present invention can be particularly suitably used for a heat-sensitive recording material having water resistance, oil resistance, and light resistance. For example, it can be suitably used for heat-sensitive recording materials such as barcode labels and register receipts used in facsimiles, measuring devices, medical devices, POS systems, and the like.

Claims (7)

A developer for heat-sensitive recording material, comprising a compound represented by the following general formula [1].

In the general formula [1], R ₁ is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, an alkoxy group, And a halogen atom. n represents an integer of 1 to 4, and when n is 2 to 4, R ₁ existing in one molecule may be the same or different.
R ₂ is selected from hydrogen, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, an alkoxy group, and a halogen atom. It is what m represents an integer of 1 to 4, and when m is 2 to 4, R ₂ existing in one molecule may be the same or different. 2. The color for a heat-sensitive recording material according to claim 1, wherein in the compound represented by the general formula [1], R ₁ is selected from hydrogen, a methyl group, and an isopropyl group, and n = 1-3. Agent. In the compound represented by the general formula [1], R ₂ is selected from hydrogen, a hydroxyl group, and a methyl group, and m = 1 to 3. Coloring agent. A developer for a heat-sensitive recording material comprising the compound represented by the general formula [1] in an amount of 50% by weight or more based on the whole developer. A method for producing a developer for a heat-sensitive recording material according to any one of claims 1 to 4,
(A) A cyclohexanone compound represented by the following general formula [2] and a phenol compound represented by the following general formula [3] are reacted in the presence of an acidic catalyst to produce a cyclohexene represented by the following general formula [4]. Synthesizing a silidene bisphenol compound, and
(B) reacting the cyclohexylidenebisphenol compound with an acetylating agent to synthesize a compound represented by the above general formula [1],
A method for producing a developer for a heat-sensitive recording material, comprising:

In the general formulas [2] and [4], R ₁ is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted aralkyl group. , An alkoxy group, and a halogen atom. n represents an integer of 1 to 4, and when n is 2 to 4, R ₁ existing in one molecule may be the same or different.
In the general formulas [3] and [4], R ₂ represents hydrogen, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted group. It is selected from an aralkyl group, an alkoxy group, and a halogen atom. m represents an integer of 1 to 4, and when m is 2 to 4, R ₂ existing in one molecule may be the same or different. A heat-sensitive recording material comprising the developer for a heat-sensitive recording material according to claim 1 and a leuco dye. A heat-sensitive recording material comprising the heat-sensitive recording material according to claim 6 coated on a support.