JP2005194428A - Isocyanate composition, microcapsule and method for producing the same and recording material thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an isocyanate composition and a microcapsule that is useful as a wall material for microcapsule wherein the microcapsules made of the wall material shows excellent properties, for example, high thermal sensitivity, high color consistency and retain good raw storability for a long period of time, provide a heat-sensitive recording material that is prepared by using the microcapsules and has high sensitivity, color reproducibility and raw storability and further provide a method for producing the useful microcapsules. <P>SOLUTION: The isocyanate composition is produced by reaction between a compound (A) that is previously prepared by allowing polymerizable monomers including at least a monomer bearing mesogene group to radically polymerize in the presence of a chain transfer agent bearing an active hydrogen and a polyfunctional isocyanate (B) bearing two or more isocyanate groups, and microcapsules using the isocyanate composition. The isocyanate composition includes the monomer bearing a mesogene group represented by general formula (I). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a novel isocyanate composition, a microcapsule formed using the isocyanate composition, a recording material containing the microcapsule, and a method for producing the microcapsule.

  Polyvalent isocyanate compounds are widely used as raw materials for polyurethane, polyurea resin, urethane elastomer and the like. The polyisocyanate compound is also effective as a wall material when microcapsules are formed by the interfacial polymerization method, and the microcapsules thus prepared can be used for, for example, pressure-sensitive recording materials, heat-sensitive recording materials, and adhesives. It is applied to agents.

  The above-mentioned heat-sensitive recording material, which is widely used as a recording medium for facsimiles and printers, is used as a material obtained by applying a solid dispersion of an electron donating dye precursor on a support and drying it. Such a recording method using an electron-donating dye precursor has the advantage that the material is easily available and exhibits high color density and heat sensitivity. However, color development occurs due to storage conditions after recording, heating, or adhesion of a solvent or the like. There are problems with the storability and reliability of recorded images, and many improvements have been studied.

  As one method for improving the storability of a recorded image, an electron donating dye precursor is encapsulated in a microcapsule, and the dye precursor and the developer are isolated in the recording layer, thereby preserving the image. A method for improving the performance has been proposed. By this method, high color developability and image stability can be obtained.

  As other heat-sensitive recording materials, so-called diazo-type heat-sensitive recording materials using diazonium salt compounds have been put into practical use. This diazonium salt compound reacts with a phenol derivative or a compound (coupler) having an active methylene group to form a dye, but also has photosensitivity and loses its activity upon irradiation with light. Utilizing these properties, it has recently been applied to heat-sensitive recording materials. A photo-fixing type heat-sensitive recording material that can form images by reacting diazonium salts and couplers with heat and then fixed by irradiation with light. (For example, refer nonpatent literature 1).

  However, since the recording material using the diazonium salt compound has high chemical activity, there is a drawback that the diazonium salt and the coupler react gradually even at a low temperature, resulting in a short shelf life. As one solution to this problem, a method has been proposed in which a diazonium salt compound is encapsulated in microcapsules and is isolated from couplers, water, and basic compounds (see, for example, Non-Patent Document 2).

  As one of the application fields of thermal recording materials, multicolor thermal recording materials are attracting attention. Reproduction of multicolor images by thermal recording has been considered difficult compared to electrophotographic recording systems and ink-jet recording systems. However, in this regard, an electron-donating dye precursor and a developer are already contained on a support as main components. It is seen that a multicolor thermosensitive recording material can be obtained by laminating two or more thermosensitive recording layers containing a diazonium salt compound and a coupler that reacts with the diazonium salt compound and develops color when heated. Has been issued. In this multicolor thermosensitive recording material, in order to obtain excellent color reproducibility, it is essential to highly control the thermochromic property of the microcapsules.

  Conventionally, in order to include an electron donating dye precursor or a diazonium salt compound in a microcapsule, for example, these compounds are dissolved in an organic solvent (oil phase), and this is dissolved in an aqueous solution containing a water-soluble polymer ( A method of emulsifying and dispersing in an aqueous phase is well known. At this time, by adding a monomer or prepolymer as a wall material to either the organic solvent phase side or the aqueous phase side, a polymer wall is formed at the interface between the organic solvent phase and the aqueous phase to form microcapsules. (For example, see Non-Patent Documents 3 and 4). As the microcapsule wall thus formed, various materials such as gelatin, alginate, celluloses, polyurea, polyurethane, melamine resin, and nylon can be used. In particular, polyurea and polyurethane resin have a glass transition temperature in the range from room temperature to around 200 ° C., so that the capsule wall can exhibit thermal responsiveness, which is convenient for designing a heat-sensitive recording material.

  As a method for producing the microcapsule, when forming a microcapsule having a polyurethane or polyurea wall, first, a diazonium salt or an electron-donating dye precursor is dissolved in an organic solvent, and a polyvalent isocyanate compound is added thereto. The organic phase solution is emulsified and dispersed in an aqueous solution containing a water-soluble polymer. Thereafter, a method of forming a capsule wall by polymerizing a polyvalent isocyanate compound with a compound having active hydrogen such as water by adding a catalyst for promoting polymerization reaction to the aqueous phase or raising the temperature of the emulsified dispersion. Well known from the past.

As the polyurea compound which is a material for forming the above polyurea or polyurethane wall, for example, an adduct of 2,4-tolylene diisocyanate and trimethylolpropane, an adduct of xylylene diisocyanate and trimethylolpropane and the like are known. (For example, see Patent Documents 1 and 2).
However, even with polyurea or polyurethane capsule walls using polyisocyanate compounds as described above, the short shelf life (shelf life) when using the aforementioned diazonium salt compounds is still sufficiently improved. Absent. That is, the heat-sensitive recording material whose shelf life is not sufficiently long, for example, when it is placed under high-temperature and high-humidity conditions after production, the color development of the background called “fogging” appears, Reduce the visibility of the recorded image. In order to solve such a problem, for example, there is a means of increasing the wall thickness of the microcapsule. However, when this method is used, color development sensitivity during thermal recording is reduced. Therefore, it has been very difficult to further improve the shelf life while maintaining high color developability.

  In order to solve such a problem, a method is known in which a part of a polyvalent isocyanate compound is reacted with a monoalcohol compound in advance (see, for example, Patent Document 3). However, a specific example of the monoalcohol used in this case is a compound having about 2 to 9 carbon atoms. When the alcohol usage rate is further increased, the sensitivity is improved, but the “fogging” increases. Conversely, if the alcohol usage rate is lowered, “fogging” can be prevented, but the effect of improving the sensitivity is insufficient.

  Further, in the multicolor thermosensitive recording material, cyan, magenta, and yellow thermosensitive recording layers are provided, and these are recorded by applying different heating temperatures. Therefore, the thermosensitive recording layer of a normal thermosensitive recording material is used. Compared to the above, further excellent thermal response is required. The above-mentioned conventional polyurea or polyurethane capsule walls do not sufficiently satisfy this requirement.

  It is also known to add a thermal sensitizer in the color developing layer of the heat sensitive recording material in order to improve the heat sensitivity. As such a thermal sensitizer, p-toluenesulfonamide and the like are already known to exhibit excellent performance (see, for example, Patent Document 4), but specific substitutions have been proposed as exhibiting further superior performance. And arylsulfonamide compounds having a group (see, for example, Patent Document 5). Further, in a multicolor thermosensitive recording material, it is necessary to emulsify and use the above arylsulfonamide compound in order to reduce the haze of the thermosensitive coloring layer. The emulsification method is not particularly limited, and a conventionally known method can be used. Specifically, the arylsulfonamide compound is dissolved in an organic solvent that is hardly soluble or insoluble in water, and this is mixed with an aqueous phase having a surfactant and / or a water-soluble polymer as a protective colloid and stirred. It is set as an emulsified dispersion (for example, refer patent document 6).

  However, since the heat sensitizer as described above is usually a crystalline substance, an emulsion containing the heat sensitizer may cause problems such as crystal precipitation due to long-term aging. Therefore, there is a strong demand for the development of microcapsules that have sufficient thermal sensitivity without using a heat sensitizer or using a small amount.

From such a viewpoint, (A) at least one of a polyether chain, a polyester chain, and a vinyl monomer (co) polymer chain having one active hydrogen in the molecule and an average molecular weight of 500 to 20,000. And a thermoresponsive microcapsule composed of a polymer obtained by polymerization of an isocyanate compound containing an adduct of a compound having (B) a polyfunctional isocyanate having two or more isocyanate groups in the molecule (for example, Patent Document 7) describes that a microcapsule having both suppression of background fogging and high color development is provided. Also disclosed is a microcapsule having a polyurea shell, characterized in that the isocyanate used for the production is a reaction product of at least a difunctional isocyanate and a monovalent poly (ethylene oxide) alcohol (for example, a patent) Reference 8) describes that small microcapsules can be obtained at low emulsification costs.
However, in the above Patent Document 7, as a compound having one active hydrogen in the molecule and an average molecular weight of 500 to 20,000, in the presence of a mercapto compound such as mercaptoethanol or mercaptoacetic acid and a radical polymerization initiator. Polymers obtained by radical polymerization of vinyl monomers are described in the specification, but as the vinyl monomers, homopolymers such as methyl (meth) acrylate and (meth) acrylamide are liquid crystalline and crystalline. Only monomers having no property are exemplified, and only polyether derivatives in which the functional group having active hydrogen is a hydroxyl group are described in the examples. Furthermore, no mention is made of the remarkable effect exhibited by the polymer having mesogenic groups according to the present invention.
Japanese Unexamined Patent Publication No. Sho 62-212190 Japanese Patent Laid-Open No. 04-026189 JP 05-317694 A Japanese Patent Publication No. 06-055546 Japanese Patent Application Laid-Open No. 09-039389 Japanese Patent Laid-Open No. 02-141279 Japanese Patent Laid-Open No. 10-114153 Japanese Patent No. 3266330 Koji Sato et al., "Journal of the Institute of Image Electronics Engineers of Japan" (Vol. 11, No. 4, 290-296, 1982) Usami Tomomasa et al., “The Journal of Electrophotographic Society” (Vol. 26, No. 2, pages 115-125, 1987) Asahi Kondo “Microcapsule” (Nikkan Kogyo Shimbun, 1970) Kondo et al. “Microcapsules” (Sankyo Publishing, 1977)

The inventors of the present invention have made extensive studies with regard to isocyanates used for forming microcapsules and the like, particularly from the viewpoint of further improving shelf life (storage stability) while maintaining high color development in application to heat-sensitive recording materials. As a result, the present invention has been completed. That is,
The present invention provides an isocyanate composition that can be suitably used for a heat-sensitive recording material and the like, exhibits high color developability upon contact with a coupler or developer, and enables formation of microcapsules excellent in raw storage stability. For the purpose.
It is another object of the present invention to provide a recording material, particularly a heat-sensitive recording material, using the microcapsule, having high sensitivity, high color developability and excellent raw storage (long shelf life). A further object of the present invention is to provide a multicolor thermosensitive recording material having high sensitivity and excellent color reproducibility and raw storage.
Another object of the present invention is to provide a method for producing such useful microcapsules.

〔上式（Ｉ）において、Ｒ¹は水素原子、又はメチル基を表し、Ｇ¹は−ＣＯＯ−、−ＣＯ・Ｎ（Ｒ³）−、又は−Ａｒ−Ｇ²−を表す。ここで、上記Ｒ³は水素原子、アルキル基、又はアリール基を表し、上記Ａｒはアリーレン基を表し、上記Ｇ²は単結合、−Ｏ−、−ＣＯＯ−、−Ｏ・ＣＯ−、−Ｏ・ＣＯＯ−、−ＣＯ・Ｎ（Ｒ⁴）−、又は−Ｎ（Ｒ⁵）・ＣＯ−を表し、該Ｒ⁴とＲ⁵はそれぞれ独立に水素原子、又はアルキル基を表す。Ａ¹は単結合、又は−Ｌ¹−Ｇ³−を表す。ここで、上記Ｌ¹はアルキレン基、又はアルキレン鎖中に２価の官能基を有する基を表し、上記Ｇ³は単結合、−Ｏ−、−ＣＯＯ−、−Ｏ・ＣＯ−、−Ｏ・ＣＯＯ−、−ＣＯ・Ｎ（Ｒ⁶）−、又は−Ｎ（Ｒ⁷）−ＣＯ−を表し、該Ｒ⁶とＲ⁷はそれぞれ独立に水素原子、又はアルキル基を表す。Ｍはメソゲン基を表し、Ｒ²は水素原子、ハロゲン原子、アルキル基、アルコキシ基、アルコキシカルボニル基、アシルオキシ基、アルコキシカルボニルオキシ基、カルバモイル基、アシルアミノ基、又はシアノ基を表す。〕
＜３＞ ポリウレタン及び／又はウレア壁を有するマイクロカプセルにおいて、該カプセル壁が、少なくともメソゲン基を有するモノマーを含む重合可能なモノマーを活性水素を有する連鎖移動剤の存在下にラジカル重合した化合物を共有結合を介して含有していることを特徴とするマイクロカプセル。
＜４＞ 前記メソゲン基を有するモノマーが、下記一般式（Ｉ）で表される化合物であることを特徴とする上記<３>に記載のマイクロカプセル。

〔上式（Ｉ）において、Ｒ¹は水素原子、又はメチル基を表し、Ｇ¹は−ＣＯＯ−、−ＣＯ・Ｎ（Ｒ³）−、又は−Ａｒ−Ｇ²−を表す。ここで、上記Ｒ³は水素原子、アルキル基、又はアリール基を表し、上記Ａｒはアリーレン基を表し、上記Ｇ²は単結合、−Ｏ−、−ＣＯＯ−、−Ｏ・ＣＯ−、−Ｏ・ＣＯＯ−、−ＣＯ・Ｎ（Ｒ⁴）−、又は−Ｎ（Ｒ⁵）・ＣＯ−を表し、該Ｒ⁴とＲ⁵はそれぞれ独立に水素原子、又はアルキル基を表す。Ａ¹は単結合、又は−Ｌ¹−Ｇ³−を表す。ここで、上記Ｌ¹はアルキレン基、又はアルキレン鎖中に２価の官能基を有する基を表し、上記Ｇ³は単結合、−Ｏ−、−ＣＯＯ−、−Ｏ・ＣＯ−、−Ｏ・ＣＯＯ−、−ＣＯ・Ｎ（Ｒ⁶）−、又は−Ｎ（Ｒ⁷）−ＣＯ−を表し、該Ｒ⁶とＲ⁷はそれぞれ独立に水素原子、又はアルキル基を表す。Ｍはメソゲン基を表し、Ｒ²は水素原子、ハロゲン原子、アルキル基、アルコキシ基、アルコキシカルボニル基、アシルオキシ基、アルコキシカルボニルオキシ基、カルバモイル基、アシルアミノ基、又はシアノ基を表す。〕
＜５＞ イソシアネート化合物を用いて製造されたマイクロカプセルにおいて、使用するイソシアネート化合物が少なくとも上記<１>又は<２>に記載のイソシアネート組成物を含むことを特徴とするポリウレタン及び／又はウレア壁を有するマイクロカプセル。
＜６＞ 上記<３>〜<５>のいずれかに記載のマイクロカプセルを含む記録層を有することを特徴とする記録材料。
＜７＞ 前記マイクロカプセルがジアゾニウム塩化合物又は電子供与性染料前駆体を内包することを特徴とする上記<３>〜<５>のいずれかに記載のマイクロカプセル。
＜８＞ 支持体上に、ジアゾニウム塩化合物を内包するマイクロカプセルとカプラー、又は電子供与性染料前駆体を内包するマイクロカプセルと顕色剤を含む感熱記録層を設けた感熱記録材料であって、該マイクロカプセルが上記<７>に記載のマイクロカプセルであることを特徴とする感熱記録材料。
＜９＞ 支持体上に、シアン、マゼンタ、及びイエローの感熱記録層が設けられ、各感熱記録層がジアゾニウム塩化合物を内包するマイクロカプセルとカプラー、又は電子供与性染料前駆体を内包するマイクロカプセルと顕色剤を含んでなる多色感熱記録材料であって、該マイクロカプセルの少なくとも１種が上記<７>に記載のマイクロカプセルであることを特徴とする多色感熱記録材料。
＜１０＞ イソシアネート化合物を用いるマイクロカプセルの製造方法において、使用するイソシアネート化合物が少なくとも上記<１>又は<２>に記載のイソシアネート組成物を含むことを特徴とするポリウレタン及び／又はウレア壁を有するマイクロカプセルの製造方法。 Means of the present invention for solving the above problems are as follows. That is,
<1> (A) a compound obtained by radical polymerization of a polymerizable monomer including a monomer having at least a mesogenic group in the presence of a chain transfer agent having active hydrogen; and (B) having two or more isocyanate groups in the molecule. An isocyanate composition comprising a reaction product with a polyfunctional isocyanate.
<2> The isocyanate composition according to <1>, wherein the monomer having a mesogenic group is a compound represented by the following general formula (I).

[In the above formula (I), R ¹ represents a hydrogen atom or a methyl group, and G ¹ represents —COO—, —CO · N (R ³ ) —, or —Ar—G ² —. Here, R ³ represents a hydrogen atom, an alkyl group, or an aryl group, Ar represents an arylene group, and G ² represents a single bond, —O—, —COO—, —O · CO—, —O. · COO -, - CO · N (R 4) -, or -N represents (R ⁵⁾ · CO-, wherein R ⁴ and R ⁵ independently represents a hydrogen atom, or an alkyl group. A ¹ represents a single bond or -L ¹ -G ^3- . Here, L ¹ represents an alkylene group or a group having a divalent functional group in the alkylene chain, and G ³ represents a single bond, —O—, —COO—, —O · CO—, —O ·. COO—, —CO · N (R ⁶ ) —, or —N (R ⁷ ) —CO— is represented, and each of R ⁶ and R ⁷ independently represents a hydrogen atom or an alkyl group. M represents a mesogenic group, and R ² represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, an alkoxycarbonyloxy group, a carbamoyl group, an acylamino group, or a cyano group. ]
<3> In a microcapsule having a polyurethane and / or urea wall, the capsule wall shares a compound obtained by radical polymerization of a polymerizable monomer containing a monomer having at least a mesogenic group in the presence of a chain transfer agent having active hydrogen. A microcapsule characterized by containing via a bond.
<4> The microcapsule according to <3>, wherein the monomer having a mesogenic group is a compound represented by the following general formula (I).

[In the above formula (I), R ¹ represents a hydrogen atom or a methyl group, and G ¹ represents —COO—, —CO · N (R ³ ) —, or —Ar—G ² —. Here, R ³ represents a hydrogen atom, an alkyl group, or an aryl group, Ar represents an arylene group, and G ² represents a single bond, —O—, —COO—, —O · CO—, —O. · COO -, - CO · N (R 4) -, or -N represents (R ⁵⁾ · CO-, wherein R ⁴ and R ⁵ independently represents a hydrogen atom, or an alkyl group. A ¹ represents a single bond or -L ¹ -G ^3- . Here, L ¹ represents an alkylene group or a group having a divalent functional group in the alkylene chain, and G ³ represents a single bond, —O—, —COO—, —O · CO—, —O ·. COO—, —CO · N (R ⁶ ) —, or —N (R ⁷ ) —CO— is represented, and each of R ⁶ and R ⁷ independently represents a hydrogen atom or an alkyl group. M represents a mesogenic group, and R ² represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, an alkoxycarbonyloxy group, a carbamoyl group, an acylamino group, or a cyano group. ]
<5> In a microcapsule produced using an isocyanate compound, the isocyanate compound to be used has a polyurethane and / or urea wall characterized in that it contains at least the isocyanate composition described in <1> or <2> above. Micro capsule.
<6> A recording material comprising a recording layer containing the microcapsule according to any one of <3> to <5>.
<7> The microcapsule according to any one of <3> to <5>, wherein the microcapsule includes a diazonium salt compound or an electron-donating dye precursor.
<8> A thermosensitive recording material in which a microcapsule enclosing a diazonium salt compound and a coupler, or a microcapsule encapsulating an electron-donating dye precursor and a thermosensitive recording layer containing a developer are provided on a support, A heat-sensitive recording material, wherein the microcapsule is the microcapsule according to the above <7>.
<9> Microcapsules in which cyan, magenta, and yellow thermosensitive recording layers are provided on a support, and each thermosensitive recording layer encapsulates a diazonium salt compound and an electron donating dye precursor And a color developer, wherein at least one of the microcapsules is the microcapsule according to the above <7>.
<10> In the method for producing a microcapsule using an isocyanate compound, the isocyanate compound to be used contains at least the isocyanate composition described in <1> or <2> above, and has a polyurethane and / or a urea wall. Capsule manufacturing method.

  The novel isocyanate composition of the present invention is useful as a wall material of a microcapsule, etc., and the microcapsule formed using this has a high sensitivity to heat, and a high color density can be quickly obtained by contact with a coupler or a developer. In addition, when a diazonium salt compound is used as the core material, it has excellent characteristics such as excellent life preservation (long shelf life) over a long period of time. Moreover, it has sufficient color developability without reducing or using a heat sensitizer. When the above-described microcapsules of the present invention are applied to a heat-sensitive recording layer, a heat-sensitive recording material having high sensitivity and color developability and excellent raw storage stability can be provided when a diazonium salt compound is used. Furthermore, the multicolor thermosensitive recording material of the present invention using the microcapsules in the thermosensitive recording layer is a multicolor thermosensitive recording material having high sensitivity and excellent color reproducibility and raw storage. The present invention can also provide a method for producing such useful microcapsules as described above.

The isocyanate composition of the present invention comprises (A) a compound obtained by radical polymerization of a polymerizable monomer containing a monomer having at least a mesogenic group in the presence of a chain transfer agent having active hydrogen, and (B) two or more in the molecule. It is a novel isocyanate composition characterized by including the reaction product with the polyfunctional isocyanate which has the following isocyanate group.
Hereinafter, the isocyanate composition of the present invention will be described in detail.

(Isocyanate composition)
First, (A) a compound obtained by radical polymerization of a polymerizable monomer containing at least a monomer having a mesogenic group in the presence of a chain transfer agent having active hydrogen will be described.
In the radical polymerization of the present invention, the monomer having a mesogenic group includes a compound having a mesogenic group and one ethylenically unsaturated double bond capable of addition polymerization in the molecule. Here, the mesogenic group refers to a functional group in the core portion of a rod-like or plate-like compound exhibiting liquid crystallinity. "POLYMERS" (B. McARDLE, Blackie and Son Ltd, 1989)), "Liqui-Crystal Polymers" (NA Plate, Plenum Press, 1993), "Liquid Crystal Polymers-Its Fundamentals and Applications-" (Iimura Kazuka) Asada Tadahiro, Abe Akihiro, Sigma Publishing, 1988), “Liquid Crystal Handbook” (Maruzen, 2000) can be referred to.

Examples of such a monomer having a mesogenic group include those described in JP-A-11-21269, JP-A-11-148080, JP-A-11-148079, and JP-A-11-100575. Can be helpful.
In the present invention, particularly preferable monomers having a mesogenic group include compounds represented by the following general formula (I).

In the general formula (I), R ¹ represents a hydrogen atom or a methyl group.
In the general formula (I), G ¹ represents —COO—, —CO · N (R ³ ) —, or —Ar—G ² —. Here, R ³ represents a hydrogen atom, an alkyl group, or an aryl group, Ar represents an arylene group, and G ² represents a single bond, —O—, —COO—, —O · CO—, —O. · COO -, - CO · N (R 4) -, or -N represents (R ⁵⁾ · CO-, wherein R ⁴ and R ⁵ independently represents a hydrogen atom, or an alkyl group.
Of the groups represented by G ¹ , —COO— is preferable.

The alkyl group represented by R ³ may have a substituent or may have a branch, and preferably has 1 to 30 carbon atoms, particularly 1 to 20 carbon atoms. preferable. As said substituent, an aryl group, an alkenyl group, and an alkoxy group are preferable. Specific examples of such an alkyl group include a methyl group, an ethyl group, a butyl group, an isopropyl group, a behenyl group, a benzyl group, an allyl group, an oleyl group, and a methoxyethyl group.

The aryl group represented by R ³ may have a substituent, preferably has 6 to 30 carbon atoms, and particularly preferably has 6 to 20 carbon atoms. The substituent is preferably a halogen atom, an alkyl group, or an alkoxy group, and particularly preferably an alkyl group or an alkoxy group. Specific examples of such an aryl group include phenyl group, nonylphenyl group, octylphenyl group, fluorophenyl group, methoxyphenyl group, and the like.
As mentioned above, among the groups represented by R ³ , a hydrogen atom and an alkyl group are preferable, and a hydrogen atom is particularly preferable.

  The arylene group represented by Ar may have a substituent, preferably has 6 to 30 carbon atoms, and particularly preferably has 6 to 20 carbon atoms. The substituent is preferably a halogen atom, an alkyl group, or an alkoxy group, and particularly preferably an alkyl group or an alkoxy group. Specific examples of such an arylene group include 1,4-phenylene group, 1,3-phenylene group, 1,2-phenylene group, naphthalene-2,6-diyl group, 3-methyl-1,4-phenylene. Among them, 1,4-phenylene group is particularly preferable.

Among the groups represented by G ² , —O—, —COO—, —O · CO—, —CO · N (R ⁴ ) —, and —N (R ⁵ ) · CO— are particularly preferable — O -, - COO -, - CO · N (R 4) - is preferred.
The alkyl group represented by R ⁴ and R ⁵ may have a substituent, may have a branch, and preferably has 1 to 30 carbon atoms, particularly 1 to 20 Are preferred. As said substituent, an aryl group, an alkenyl group, and an alkoxy group are preferable. Specific examples of such an alkyl group include a methyl group, an ethyl group, a butyl group, an isopropyl group, a behenyl group, a benzyl group, an allyl group, an oleyl group, and a methoxyethyl group.
R ⁴ and R ⁵ are preferably hydrogen atoms.

In the general formula (I), A ¹ is a single bond, or -L ¹ -G ³ - represents a. Here, L ¹ represents an alkylene group or a group having a divalent functional group in the alkylene chain, and G ³ represents a single bond, —O—, —COO—, —O · CO—, —O ·. COO—, —CO · N (R ⁶ ) —, or —N (R ⁷ ) —CO— is represented, and each of R ⁶ and R ⁷ independently represents a hydrogen atom or an alkyl group.

The alkylene group represented by L ¹ may have a substituent or may have a branch, and preferably has 1 to 30 carbon atoms, particularly preferably 1 to 20 carbon atoms. preferable. As the substituent, a halogen atom, an aryl group, an alkenyl group, an alkoxy group and an alkoxycarbonyl group are preferable, and a halogen atom is particularly preferable. Examples of the divalent functional group include —O—, —S—, —COO—, —O · CO—, —O · COO—, —CONH—, —NHCO—, —NHCOO—, —O · CONH—, —NHCONH— is preferable, and —O—, —COO—, —O · CO—, —NHCOO—, and —NHCONH— are particularly preferable.

Among the groups represented by G ³ , —O—, —COO—, —O · CO—, —CO · N (R ⁶ ) —, and —N (R ⁷ ) · CO— are particularly preferable — O -, - COO -, - CO · N (R 6) - is preferred.
The alkyl group represented by R ⁶ and R ⁷ may have a substituent or may have a branch, and preferably has 1 to 30 carbon atoms, particularly 1 to 20 Are preferred. As said substituent, an aryl group, an alkenyl group, and an alkoxy group are preferable. Specific examples of such an alkyl group include a methyl group, an ethyl group, a butyl group, an isopropyl group, a behenyl group, a benzyl group, an allyl group, an oleyl group, and a methoxyethyl group.
As described above, among the groups represented by R ⁶ and R ⁷ , a hydrogen atom is preferable.

In general formula (I), M represents a mesogenic group.
Specific examples of the mesogenic group represented by M include the following groups (a) to (l).

In the above formulas (a) to (l), R ^{6 to} R ⁸ represent a halogen atom, an alkyl group, or an alkoxy group, and among them, a halogen atom and an alkyl group are preferable. R ^{9 to} R ¹⁰ represent a halogen atom, an alkyl group, or an alkoxy group, and among them, an alkyl group is preferable. R ^{11 to} R ¹³ represent a halogen atom, an alkyl group, or an alkoxy group, and among them, an alkyl group is preferable.
As the halogen atom represented by R ^{6 to} R ¹³ , a fluorine atom, a chlorine atom and a bromine atom are preferable, and a chlorine atom and a bromine atom are particularly preferable.

The alkyl group represented by R ^{6 to} R ¹³ may have a substituent, preferably has 1 to 12 carbon atoms, and particularly preferably has 1 to 6 carbon atoms.
The alkoxy group represented by R ^{6 to} R ¹³ may have a substituent, preferably has 1 to 12 carbon atoms, and particularly preferably has 1 to 6 carbon atoms.

In the above formulas (a) to (l), a to c represent an integer of 0 to 2, and 0 or 1 is preferable. de represents the integer of 0-2, and 0 is preferable. f to h represent an integer of 0 to 4, and 0 is preferable.
In the above formulas (a) to (l), X and Y are a single bond, —CH═CH—, an ethenylene group, —COO—, —O · CO—, —CONH—, —NHCO—, —N═N—. , -N (→ O) = N-, -CH = N-, -N = CH-, among these, a single bond, ethenylene, -COO-, -O.CO-, -CONH-, -NHCO -Is preferable, and a single bond, -COO-, and -CONH- are particularly preferable.

In the above formulas (a) to (l), Z is a single bond, —CH═CH—, ethenylene group, —COO—, —O · CO—, —CONH—, —NHCO—, —N═N—, — N (→ O) = N—, —CH═N—, —N═CH—, and among these, a single bond, ethenylene, —COO—, —O · CO—, —CONH—, —NHCO— Particularly preferred are a single bond and an ethenylene group.
As described above, among the mesogenic groups represented by M, the groups represented by the above (a), (b), (c) and (d) are preferable, and particularly the groups represented by (a) and (b). Is preferred.

In the general formula (I), R ² represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, an alkoxycarbonyloxy group, a carbamoyl group, an acylamino group, or a cyano group.
As the halogen atom represented by R ² , a fluorine atom, a chlorine atom and a bromine atom are preferable, and a chlorine atom and a bromine atom are particularly preferable.

The alkyl group represented by R ² may have a substituent or may have a branch, and those having 1 to 30 carbon atoms are preferable, and those having 1 to 20 are particularly preferable. preferable. As said substituent, a halogen atom, an aryl group, an alkenyl group, and an alkoxy group are preferable. Specific examples of such an alkyl group include a methyl group, an ethyl group, a butyl group, an isopropyl group, a behenyl group, a trifluoromethyl group, a benzyl group, an allyl group, an oleyl group, and a methoxyethyl group.

The alkoxy group represented by R ² may have a substituent or may have a branch, and preferably has 1 to 30 carbon atoms, particularly 1 to 20 carbon atoms. preferable. As the substituent, a halogen atom, an aryl group, an alkenyl group, an alkoxy group, an alkoxycarbonyl group, and a carbamoyl group are preferable. Specific examples of such alkoxy groups include methoxy group, ethoxy group, isopropoxy group, fluoroethoxy group, benzyloxy group, allyloxy group, methoxyethoxy group, methoxycarbonylmethoxy group, N, N-dimethylcarbamoylmethoxy group, Etc.

The alkoxycarbonyl group represented by R ² may have a substituent or may have a branch, and preferably has 2 to 30 carbon atoms, particularly 2 to 20 carbon atoms. Is preferred. As the substituent, a halogen atom, an aryl group, an alkenyl group, an alkoxy group, an alkoxycarbonyl group, and a carbamoyl group are preferable. Specific examples of such alkoxycarbonyl group include methoxycarbonyl group, ethoxycarbonyl group, isopropoxycarbonyl group, fluoroethoxycarbonyl group, benzyloxycarbonyl group, allyloxycarbonyl group, methoxyethoxycarbonyl group, methoxycarbonylmethoxycarbonyl group. , Etc.

The acyloxy group represented by R ² may have a substituent, may have a branch, may be aliphatic or aromatic, and has 2 to 30 carbon atoms. Particularly preferred is 2-20. As the substituent, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an alkoxycarbonyl group, and a carbamoyl group are preferable. Specific examples of such acyloxy groups include acetoxy group, 2-ethylhexanoyloxy group, benzoyloxy group, trifluoroacetyloxy group, 4-fluorobenzoyloxy group, biphenylcarbonyloxy group, butenoyloxy group, methoxyacetyloxy Group, 4-octyloxybenzoyloxy group, 4-methoxycarbonylbenzoyloxy group, 4-N-butylcarbamoylbenzoyloxy group, and the like.

The alkoxycarbonyloxy group represented by R ² may have a substituent or may have a branch, and preferably has 2 to 30 carbon atoms, particularly 2 to 20 carbon atoms. Those are preferred. As the substituent, a halogen atom, an aryl group, an alkenyl group, an alkoxy group, an alkoxycarbonyl group, and a carbamoyl group are preferable. Specific examples of such alkoxycarbonyloxy group include methoxycarbonyloxy group, ethoxycarbonyloxy group, isopropoxycarbonyloxy group, fluoroethoxycarbonyloxy group, benzyloxycarbonyloxy group, allyloxycarbonyloxy group, methoxyethoxycarbonyl An oxy group, a methoxycarbonylmethoxycarbonyloxy group, etc. are mentioned.

Examples of the carbamoyl group represented by R ² include unsubstituted carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, and N-alkyl-N. -Arylcarbamoyl group may be used, and the alkyl group and aryl group may have a substituent, may have a branch, and preferably have 1 to 30 carbon atoms. Those of 1 to 20 are preferred. As the substituent, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, and an alkoxycarbonyl group are preferable. Specific examples of such a carbamoyl group include —CONH ₂ , N-methylcarbamoyl, N-butylcarbamoyl group, N-phenylcarbamoyl group, N-methoxyethylcarbamoyl group, N- (4-methylphenyl) carbamoyl group, N- (4-chlorophenyl) carbamoyl group, N-benzylcarbamoyl group, N-allylcarbamoyl group, N-methoxycarbonylmethylcarbamoyl group, N, N-diethylcarbamoyl group, N, N-diphenylcarbamoyl group, N-methyl- N-phenylcarbamoyl group, etc. are mentioned.

The acylamino group represented by R ² may have a substituent, may have a branch, may be aliphatic or aromatic, and has 2 to 30 carbon atoms. Particularly preferred is 2-20. As the substituent, a halogen atom, an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an alkoxycarbonyl group, and a carbamoyl group are preferable. Examples of such an acylamino group include acetylamino group, 2-ethylhexanoylamino group, benzoylamino group, trifluoroacetylamino group, 4-fluorobenzoylamino group, biphenylcarbonylamino group, butenoylamino group, methoxyacetylamino group, Examples include 4-octyloxybenzoylamino group, 4-methoxycarbonylbenzoylamino group, 4-N-butylcarbamoylbenzoylamino group, N-methyl-N-acetylamino group, and the like.
As described above, among the groups represented by R ² , a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group, a carbamoyl group, an acylamino group, and a cyano group are preferable, and in particular, a hydrogen atom, a halogen atom, an alkyl group, An alkoxy group and a cyano group are preferable.

  Specific examples of the compound represented by the general formula (I) described above are given below, but the present invention is not limited thereto.

As the compound obtained by radical polymerization of a polymerizable monomer containing at least a monomer having a mesogenic group in the present invention in the presence of a chain transfer agent having active hydrogen, one kind of monomer having a mesogenic group may be used alone or 2 Although polymerization may be performed using two or more species in combination, one obtained by polymerizing one species alone is preferable.
In addition, it is preferable to radically polymerize only the monomer component represented by the general formula (I), but radically polymerizable ethylenic unsaturation other than the monomer represented by the general formula (I) depending on the purpose and necessity. It can also be used by copolymerizing with a compound having a double bond.

  Examples of such a compound having an ethylenically unsaturated double bond capable of radical polymerization include (meth) acrylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate and propyl (meth). Acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) Acrylate, chloroethyl (meth) acrylate, allyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenyl (meth) acrylate, naphthyl (meth) acrylate etc:

  (Meth) acrylamides such as (meth) acrylamide, N-alkyl (meth) acrylamide (for example, methyl group, ethyl group, propyl group, butyl group, t-butyl group, octyl group, ethylhexyl group as the alkyl group) Cyclohexyl group, benzyl group, etc.), N-aryl (meth) acrylamide (as the aryl group, for example, phenyl group, naphthyl group, hydroxyphenyl group, etc.), N, N-dialkyl (meth) acrylamide (as the alkyl group). For example, a methyl group, an ethyl group, a butyl group, an isobutyl group, an ethylhexyl group, a cyclohexyl group, etc.), N, N-diaryl (meth) acrylamide (such as an aryl group such as a phenyl group), N -Methyl-N-phenyl (meth) acrylamide and the like: styrenes, For example, styrene, methyl styrene, dimethyl styrene, ethyl styrene, isopropyl styrene, butyl styrene, hexyl styrene, chloromethyl styrene, trifluoromethyl styrene, ethoxymethyl styrene, methoxy styrene, dimethoxy styrene, chloro styrene, dichloro styrene, bromo styrene, etc. : (Meth) acrylonitriles and the like.

  When the monomer represented by the general formula (I) is copolymerized with the compound having an ethylenically unsaturated bond capable of radical polymerization, radical polymerization other than the monomer of the general formula (I) and the general formula (I) is possible. As a copolymerization ratio with a compound having an ethylenically unsaturated bond, 99/1 (mass ratio) to 50/50 (mass ratio) is preferable, and in particular, 99/1 (mass ratio) to 70/30 (mass ratio). ) Is preferred.

Next, the chain transfer agent having active hydrogen used for radical polymerization of the polymerizable monomers including the monomer having at least the mesogenic group described above will be described in detail.
In the present invention, examples of the active hydrogen include a hydrogen atom in —OH (such as a hydroxyl group),> NH or —NH ₂ (such as an amino group), or —COOH (a carboxyl group).
As such a chain transfer agent having active hydrogen, thiols or disulfides are preferable, and thiols are particularly preferable. The active hydrogen (hydroxyl group, amino group, carboxyl group, etc.) contained in the chain transfer agent of the present invention is preferably 1 to 2, particularly preferably 1. The amino group is preferably a primary amino group or a secondary amino group, and particularly preferably a primary amino group. Of the above hydroxyl group, amino group, or carboxyl group, a hydroxyl group or amino group is preferred, and a hydroxyl group is particularly preferred. In addition, when it has two or more hydroxyl groups, amino groups, or carboxyl groups, these groups may be the same or different, but are preferably the same.

Specific examples of such chain transfer agents include mercaptoethanol, 1-mercapto-2-propanol, 3-mercapto-1-propanol, 3-mercapto-2-butanol, 3-mercapto-1,2-propanediol, 2 , 3-dimercapto-1-propanol, 2-aminoethanethiol, 2- (butylamino) ethanethiol, cystamine, mercaptoacetic acid, mercaptosuccinic acid, and the like.
As the usage-amount of the chain transfer agent used for this invention, 1/5 molar ratio-1/100 molar ratio are preferable with respect to all the monomer components, and 1/10 molar ratio-1/50 molar ratio are especially preferable.

Next, the radical polymerization of the present invention performed in the presence of a chain transfer agent having active hydrogen will be described.
For radical polymerization, refer to the description on pages 1 to 134 of Lecture 2 of New Polymer Experiments “Synthesis and Reaction of Polymers (1) Synthesis of Addition Polymers” (edited by the Society of Polymer Science, Kyoritsu Shuppan). it can. Examples of the radical polymerization initiator used for such radical polymerization include azo initiators and peroxides. For example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2 , 4-dimethylvaleronitrile), 2,2′-azobiscyclohexanecarbonitrile, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], benzoyl peroxide, and the like. .

As the usage-amount of the radical polymerization initiator used for this invention, 1/50 molar ratio-1/1000 molar ratio are preferable with respect to all the monomer components, and 1/100 molar ratio-1/500 molar ratio are especially preferable.
Moreover, when using a reaction solvent, ethyl acetate, methyl ethyl ketone, tetrahydrofuran, methoxypropanol, methoxypropyl acetate, cyclohexane, toluene, etc. are mentioned suitably. The amount of these reaction solvents used is preferably 0% by mass to 90% by mass, and particularly preferably 10% by mass to 70% by mass with respect to the total monomer components.
As the reaction temperature, an optimum temperature can be appropriately selected depending on the polymerization initiator and the reaction solvent to be used. In general, the temperature is preferably 30 ° C to 140 ° C, and particularly preferably 50 ° C to 120 ° C.
The average degree of polymerization of the radically polymerized compound is preferably 5 to 100, particularly preferably 0 to 50.

Next, (B) a polyfunctional isocyanate having two or more isocyanate groups in the molecule will be described.
Examples of the polyfunctional isocyanates include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, and naphthalene as compounds having two isocyanate groups in the molecule. -1,4-diisocyanate, diphenylmethane-4,4′-diisocyanate, 3,3′-dimethoxy-biphenyl diisocyanate, 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate, p-xylylene diisocyanate, m-xylylene Diisocyanate, 4-chloro-m-xylylene diisocyanate, 2-methyl-m-xylylene diisocyanate, 4,4'-diphenylpropane diisocyanate, 4,4'-diphenylhexafluoropropane diisocyanate Nate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,3-diisocyanate, cyclohexylene-1,4 -Diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,4-bis (isocyanatemethyl) cyclohexane and 1,3-bis (isocyanatemethyl) cyclohexane, isophorone diisocyanate, lysine diisocyanate, and the like. Furthermore, addition reaction products of these bifunctional isocyanate compounds with bifunctional alcohols such as ethylene glycols and bisphenols and phenols can also be used.

  Furthermore, a polyfunctional isocyanate compound having three or more isocyanate groups can also be used. Examples of such polyfunctional isocyanates are polyfunctional as adducts of the above difunctional isocyanate compounds as the main raw material and their trimers (burette or isocyanurate), polyols such as trimethylolpropane and bifunctional isocyanate compounds. , A formalin condensate of benzene isocyanate, a polymer of an isocyanate compound having a polymerizable group such as methacryloyloxyethyl isocyanate, lysine triisocyanate, and the like can also be used.

  Of the polyfunctional isocyanate compounds described above, xylylene diisocyanate, tolylene diisocyanate, xylene diisocyanate and its hydrogenated product, hexamethylene diisocyanate, tolylene diisocyanate and its hydrogenated product, etc. In addition to (burette or isosinurate), polyfunctional ones as adducts with trimethylolpropane are preferred. These compounds are described in detail in “Polyurethane Resin Handbook” edited by Keiji Iwata (published by Nikkan Kogyo Shimbun, 1987).

  Among the above, addition of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, trimethylolpropane and p-xylylene diisocyanate or m-xylylene diisocyanate In particular, an adduct of p-xylylene diisocyanate and m-xylylene diisocyanate, trimethylolpropane and p-xylylene diisocyanate or m-xylylene diisocyanate is preferred.

  A preferred isocyanate composition according to the present invention is (A) a compound obtained by radical polymerization of the monomer compound represented by the general formula (I) in the presence of a chain transfer agent having at least one hydroxyl group, amino group, or carboxyl group. And (B) an isocyanate composition comprising a reaction product bonded through a urethane, urea, or amide group, obtained by reaction with a polyfunctional isocyanate having two or more isocyanate groups in the molecule. is there.

  Furthermore, a more preferred isocyanate composition used according to the present invention includes (A) a compound obtained by radical polymerization of at least the monomer compound represented by the general formula (I) in the presence of a chain transfer agent having a hydroxyl group, and (B) Linked through urethane groups, obtained by reaction with aliphatic, cycloaliphatic and / or aromatic polyfunctional isocyanates having at least two isocyanate groups, preferably aliphatic and / or cycloaliphatic isocyanates. An isocyanate composition containing the reaction product.

In producing the isocyanate composition of the present invention, (B) an isocyanate group having at least two in the molecule, and (A) at least a monomer represented by the general formula (I) has a hydroxyl group, an amino group, or a carboxyl group. The molar ratio of the hydroxyl group, amino group or carboxyl group in the compound radically polymerized in the presence of at least one chain transfer agent is preferably 1.5 / 1 to 40/1, particularly 2/1. ~ 30/1 is preferred.
When the reaction molar ratio is 1.5 / 1 or more, a sufficient amount of isocyanate groups can be secured in the encapsulation reaction, and the encapsulation reaction can be easily performed. When the reaction molar ratio is 40/1 or less, the sensitivity can be improved when the microcapsules of the present invention are used as a heat-sensitive recording material.

The isocyanate composition of the present invention includes, for example, (A) a compound obtained by radical polymerization of at least one monomer represented by general formula (I) in the presence of a chain transfer agent having at least one hydroxyl group, amino group, or carboxyl group; (B) A compound having at least two isocyanate groups in the molecule is stirred in an organic solvent having no active hydrogen while heating (about 50 to 100 ° C.), or stannous octylate or It can be easily obtained by reacting at a relatively low temperature (about 40 to 70 ° C.) while adding a catalyst such as dibutyltin diacetate.
Specific examples of the organic solvent having no active hydrogen include, for example, ethyl acetate, chloroform, tetrahydrofuran, methyl ethyl ketone, acetone, acetonitrile, toluene and the like.
In addition, in the presence of a chain transfer agent having at least one hydroxyl group, amino group, or carboxyl group as the monomer represented by (A) at least the general formula (I), which is provided for the production of the isocyanate composition of the present invention. Each of the radically polymerized compound and the compound (B) having at least two isocyanate groups in the molecule may be a single type or a mixture of two or more types.

(Microcapsule)
The microcapsule of the present invention is a microcapsule having a polyurethane and / or urea wall, and the capsule wall contains a polymerizable monomer containing at least a monomer having a mesogenic group in the presence of a chain transfer agent having active hydrogen. It is characterized by containing a radically polymerized compound via a covalent bond. Here, the monomer having a mesogenic group is preferably a compound represented by the general formula (I). The “polyurethane and / or urea wall” refers to a polyurethane wall, a polyurea wall, or a mixed wall of polyurethane and polyurea.
The microcapsule of the present invention is a microcapsule having a polyurethane and / or urea wall, wherein the isocyanate compound used in the production of a microcapsule using an isocyanate compound includes at least the isocyanate composition of the present invention described above. Capsules are preferred.

The aforementioned isocyanate composition is suitably provided as a raw material (capsule wall material) in the production of the microcapsules of the present invention. In the production of the microcapsules of the present invention, in addition to the isocyanate composition of the present invention, a known compound having at least two isocyanate groups in the molecule can be used in combination. Specific examples thereof can be appropriately selected from the bifunctional and polyfunctional isocyanate compounds described above. The isocyanate composition of the present invention and other known polyfunctional isocyanate compounds can be used alone or in combination of two or more.
In the production of the microcapsules of the present invention, the mass ratio of the isocyanate composition of the present invention to other known polyfunctional isocyanate compounds is preferably 100/0 to 5/95, particularly 50/50 to 5/95. preferable.

The production of the microcapsules of the present invention is preferably carried out by a reaction between an isocyanate compound containing the isocyanate composition of the present invention and a compound having two or more active hydrogens in the molecule. Specific examples of the compound having two or more active hydrogens in the molecule include, for example, water, polyhydric alcohol compounds such as ethylene glycol and glycerol, polyhydric amine compounds such as ethylenediamine and diethylenetriamine, and the like. These mixtures etc. are mentioned. Among these, it is particularly preferable to perform polymerization using water. As a result, microcapsules with polyurethane and / or polyurea walls are produced.
The above polymerization is preferably carried out by reacting preferably in the temperature range of 10 to 70 ° C., more preferably 20 to 50 ° C., preferably 30 minutes to 10 hours, more preferably 1 hour to 5 hours. .

As other components necessary for producing the microcapsules, that is, substances encapsulated in the capsule, hydrophobic solvent, aqueous phase medium and the like, those corresponding to the current state of the art can be used. Examples of substances that can be encapsulated include fragrance oils, plant protection agents, reactive adhesives, diazo compounds, electron donating dye precursors, and pharmaceuticals.
When the microcapsule of the present invention is applied to a heat-sensitive recording material, it is preferably produced as a microcapsule containing a diazo compound or an electron donating dye precursor. When the diazo compound or the electron donating dye precursor is used, it is preferable to dissolve the diazo compound or the electron donating dye precursor in a high-boiling organic solvent, and if necessary, a solvent to which a low high-boiling organic solvent is added, and encapsulate the microcapsules.

(Recording material)
The recording material of the present invention is characterized by containing the above-described microcapsules of the present invention in a recording layer, particularly a heat-sensitive recording layer. Further, a thermosensitive recording material comprising a microcapsule and a coupler encapsulating a diazo compound and / or a microcapsule encapsulating an electron donating dye precursor and a thermosensitive recording layer containing a developer on a support. The microcapsule is the above-described microcapsule of the present invention.
The multicolor thermosensitive recording material of the present invention comprises, on the support, a thermosensitive recording layer that develops cyan, a thermosensitive recording layer that develops magenta, and a thermosensitive recording layer that develops yellow. Each of the layers is a multicolor thermosensitive recording material containing a microcapsule and coupler encapsulating a diazo compound, or a microcapsule encapsulating an electron-donating dye precursor and a developer, wherein at least one of the microcapsules Is the microcapsule of the present invention.
In the present invention, when a transparent support is used as the support, a black heat-sensitive recording layer may be provided on the surface of the support opposite to the surface on which the heat-sensitive recording layer is provided, if desired.

  Examples of the electron donating dye precursor encapsulated in the microcapsule of the present invention include triarylmethane compounds, diphenylmethane compounds, thiazine compounds, xanthene compounds, spiropyran compounds, and the like. And xanthene compounds are useful because of their high color density.

Specific examples thereof include 3,3-bis (p-dimethylaminophenyl) -6dimethylaminophthalide (that is, crystal violet lactone), 3,3-bis (p-dimethylamino) phthalide, 3- (p- Dimethylaminophenyl) -3- (1,3-dimethylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (o- Methyl-p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (o-methyl-p-diethylaminophenyl) -3- (1′-ethyl-2-methylindole-3) -Yl) phthalide, 4,4'-bis (dimethylamino) benzhydrin benzyl ether, N-halophenylleucooramine, N-2,4,5 Trichlorophenyl leucooramine, rhodamine-B-anilinolactam, rhodamine (p-nitroanilino) lactam, rhodamine-B- (p-chloroanilino) lactam, 2-benzylamino-6-diethylaminofluorane, 2-anilino-6 Diethylaminofluorane, 2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-cyclohexylmethylaminofluorane, 2-anilino-3-methyl-6-isoamylethylaminofluorane, 2- (o-chloroanilino) -6-diethylaminofluorane, 2-octylamino-6-diethylaminofluorane, 2-ethoxyethylamino-3-chloro-2-diethylaminofluorane, 2-anilino-3-chloro-6 -Diethylaminofur Oran, benzoyl leucomethylene blue, p-nitrobenzyl leucomethylene blue, 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3,3′-dichloro-spiro-dinaphthopyran, 3-benzylpyrodinaftpyran, 3- And propyl-spiro-dibenzopyran.
The electron donating dye precursors may be used alone or in combination of two or more.

Examples of the electron-accepting compound (developer (not included in the microcapsule)) used in combination with the electron-donating dye precursor include phenol derivatives, salicylic acid derivatives, and hydroxybenzoic acid esters. Among these, bisphenols and hydroxybenzoic acid esters are particularly preferable.
For example, 2,2-bis (p-hydroxyphenyl) propane (bisphenol A), 2,2-bis (p-hydroxyphenyl) pentane, 2,2-bis (p-hydroxyphenyl) ethane, 2,2-bis (P-hydroxyphenyl) butane, 2,2-bis (4′-hydroxy-3 ′, 5′-dichlorophenyl) propane, 1,1- (p-hydroxyphenyl) cyclohexane, 1,1- (p-hydroxyphenyl) ) Propane, 1,1- (p-hydroxyphenyl) pentane, 1,1- (p-hydroxyphenyl) -2-ethylhexane, 3,5-di (α-methylbenzyl) salicylic acid and its polyvalent metal salt, 3,5-di (tert-butyl) salicylic acid and its polyvalent metal salt, 3-α, α-dimethylbenzylsalicylic acid and its polyvalent metal salt, p-hydro Tributyl benzoic acid, p- hydroxybenzoic acid benzyl, p- hydroxybenzoate, 2-ethylhexyl can be mentioned p- phenylphenol and p- cumylphenol.
The electron accepting compounds may be used alone or in combination of two or more.

It is preferable to add a sensitizer for promoting the reaction to the heat-sensitive recording layer of the present invention. As the sensitizer, a low-melting-point organic compound having an appropriate aromatic group and polar group in the molecule is preferable. Specific examples thereof include p-benzyloxybenzoic acid benzyl, α-naphthylbenzyl ether, β-naphthylbenzyl ether, β-naphthoic acid phenyl ester, α-hydroxy-β-naphthoic acid phenyl ester, β-naphthol- (p -Chlorobenzyl) ether, 1,4-butanediol phenyl ether, 1,4-butanediol-p-methylphenyl ether, 1,4-butanediol-p-ethylphenyl ether, 1,4-butanediol-m- Methyl phenyl ether, 1-phenoxy-2- (p-tolyloxy) ethane, 1-phenoxy-2- (p-ethylphenoxy) ethane, 1-phenoxy-2- (p-chlorophenoxy) ethane, p-benzylbiphenyl, p-toluenesulfonamide, 4- (2-ethylhexylo) ) Phenyl sulfonamide, include 4-n-pentyloxyphenyl sulfonamide.
The above sensitizers may be used alone or in combination of two or more.

As the diazo compound encapsulated in the microcapsule of the present invention, a known one can be used. The diazo compound refers to a compound represented by the following general formula.
Ar-N ₂ ⁺ X ^-
In the above formula, Ar represents an aryl group, and X ⁻ represents an acid anion.

The diazo compound reacts with a phenol compound or a compound having active methylene to form a so-called dye, and further decomposes by irradiation with light (generally ultraviolet rays) and denitrifies to lose its reaction activity. is there.
Specific examples of the diazo compound include 2,5-dibutoxy-4-morpholinobenzenediazonium, 2,5-octoxy-4-morpholinobenzenediazonium, 2,5-dibutoxy-4- (N- (2-ethylhexanoyl). ) Piperazino) benzenediazonium, 2,5-diethoxy-4- (N- (2- (2,4-di-tert-amylphenoxy) butyryl) piperazino) benzenediazonium, 2,5-dibutoxy-4-tolylthiobenzene Diazonium, 2,5-dibutoxy-4-chlorobenzenethiodiazonium, 2,5-diheptyloxy-4-chlorobenzenethiodiazonium, 3- (2-octyloxyethoxy) -4-morpholinobenzenediazonium, 4- N, N-dihexylamino-2-hexyloxybenzenediazoni 4- (N-hexyl-N- (1-methyl-2- (p-methoxyphenoxy) ethyl) amino) -2-hexyloxybenzenediazonium and 4-N-hexyl-N-tolylamino-2-hexyloxy Examples thereof include benzenediazonium salts.

The acid anions in the diazo compound include hexafluorophosphate salts, tetrafluoroborate salts, 1,5-naphthalene sulfonate salts, perfluoroalkyl carbonate salts, perfluoroalkyl sulfonate salts, zinc chloride salts, and tin chloride. A salt or the like can be used. Preferably, hexafluorophosphate salt, tetrafluoroborate salt, and 1,5-naphthalene sulfonate salt are preferable because they have low water solubility and are soluble in organic solvents.
The diazo compounds may be used alone or in combination of two or more.

In a heat-sensitive recording layer using microcapsules enclosing a diazo compound, a known heat sensitizer such as an arylsulfonamide compound may be added. Specific examples include toluenesulfonamide and ethylbenzenesulfonamide. These heat sensitizers may be used alone or in combination of two or more.

A coupler that reacts with a diazo compound to form a dye is used after being finely divided by emulsifying dispersion and / or solid dispersion.
Specific examples of the coupler include resorcin, flurucosine, sodium 2,3-dihydroxynaphthalene-6-sulfonate, 1-hydroxy-2-naphthoic acid morpholinopropylamide, 1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,3-dihydroxy-6-sulfanylnaphthalene, 2-hydroxy-3-naphthoic acid anilide, 2-hydroxy-3-naphthoic acid ethanolamide, 2-hydroxy-3-naphthoic acid octylamide, 2-hydroxy-3-naphtho Acid-N-dodecyloxypurpyramide, 2-hydroxy-3-naphthoic acid tetradecylamide, acetanilide, acetoacetanilide, benzoylacetanilide, 2-chloro-5-octylacetoacetanilide, 2,5-di-n-heptyl Xiacetanilide, 1-phenyl-3-methyl-5-pyrazolone, 1- (2′-octylphenyl) -3-methyl-5-pyrazolone, 1- (2 ′, 4 ′, 6′-trichlorophenyl) -3 -Benzamido-5-pyrazolone, 1- (2 ', 4', 6'-trichlorophenyl) -3-anilino-5-pyrazolone, 1-phenyl-3-phenylacetamido-5-pyrazolone, 1- (2-dodecyl) Oxyphenyl) -2-methyl carbonate cyclohexane-3,5-dione, 1- (2-dodecyloxyphenyl) cyclohexane-3,5-dione, N-phenyl-N-dodecylbarbituric acid, N-phenyl-N- Mention of (2,5-dioctyloxyphenyl) barbituric acid and N-phenyl-N- (3-stearyloxy) butylbarbituric acid Door can be.
The above couplers may be used alone or in combination of two or more. Two or more of these couplers can be used in combination to obtain the desired color hue.

Furthermore, in order to promote the dye-forming reaction, it is common to add a basic compound which is finely divided by emulsification dispersion and / or solid dispersion. Examples of the basic compound include inorganic or organic basic compounds and compounds that release an alkaline substance by decomposition or the like when heated. Typical examples include organic ammonium salts, organic amines, amides, ureas and thioureas and their derivatives, thiazoles, pyrroles, pyrimidines, piperazines, guanidines, indoles, imidazoles, imidazolines, triazoles. , Morpholines, piperidines, amidines, formazines, pyridines and the like nitrogen-containing compounds.
Specific examples thereof include tricyclohexylamine, tribenzylamine, octadecylbenzylamine, stearylamine, allylurea, thiourea, methylthiourea, allylthiourea, ethylenethiourea, 2-benzylimidazole, 4-phenylimidazole, 2-phenyl- 4-methylimidazole, 2-undecylimidazoline, 2,4,5-trifuryl-2-imidazoline, 1,2-diphenyl-4,4-dimethyl-2-imidazoline, 2-phenyl-2-imidazoline, 1,2 , 3-triphenylguanidine, 1,2-dicyclohexylguanidine, 1,2,3-tricyclohexylguanidine, guanidine trichloroacetate, N, N′-dibenzylpiperazine, 4,4′-dithiomorpholine, morpholinium trichloro Acetate, - it can be exemplified aminobenzothiazole and 2-benzoyl-hydrazino-benzothiazole.
The above basic compounds may be used alone or in combination of two or more.

A specific production process of the microcapsule of the present invention including a diazo compound or an electron donating dye precursor is performed, for example, as follows.
As the hydrophobic solvent for forming the core of the microcapsule, an organic solvent having a boiling point of 100 to 300 ° C. is preferable. Specifically, alkyl naphthalene, alkyl diphenyl ethane, alkyl diphenyl methane, diphenyl ethane alkyl adduct, alkyl biphenyl, chlorinated paraffin, tricresyl phosphate and other maleic acid derivatives, maleic acid-di-2-ethylhexyl maleic Examples include acid esters and adipic acid esters. You may use these in mixture of 2 or more types. When the solubility of the diazonium salt compound or the electron donating dye precursor in these hydrophobic solvents is not sufficient, a low boiling point solvent can be used in combination. As the low-boiling organic solvent used in combination, an organic solvent having a boiling point of 40 to 100 ° C. is preferable, and specific examples include ethyl acetate, butyl acetate, methylene chloride, tetrahydrofuran and acetone. Moreover, you may mix and use these 2 or more types. When only a solvent having a low boiling point (a boiling point of about 100 ° C. or less) is used for the capsule core, the solvent evaporates, and a so-called coreless capsule in which only the capsule wall and the diazonium salt compound or the electron donating dye precursor exist is present. Easy to form.

Depending on the type of diazo compound, it may move to the aqueous phase side during the microencapsulation reaction, and in order to suppress this, an acid anion may be appropriately added to the water-soluble polymer solution in advance. As this acid anion, PF ₆ ⁻ , B (—Ph) ₄ ⁻ [Ph is a phenyl group], ZnCl ₂ ⁻ , C _n H _{2n + 1} COO ⁻ (n is an integer of 1 to 9) and C _p F _{2p +1} SO ₃ ⁻ (p is an integer of 1 to 9).
Various additives may be used in combination for storage stability, color development sensitivity adjustment, and the like.

  In the present invention, at the time of microencapsulation, water is generally used as a compound having active hydrogen used for polymerization of an isocyanate compound for forming a microcapsule wall, but a polyol is used as an organic solvent or a dispersion as a core substance. It can be added to a water-soluble polymer solution serving as a medium and used as a compound having one of the active hydrogens (one of the raw materials for the microcapsule wall). Specific examples include propylene glycol, glycerin, and trimethylolpropane. Further, amine compounds such as diethylenetriamine and tetraethylenepentamine may be used instead of or in combination with polyol. These compounds are also described in the above “Polyurethane Resin Handbook”.

  Water-soluble polymers for dispersing the oil phase of the microcapsules in the aqueous phase include polyvinyl alcohol and its modified products, polyacrylic acid amide and its derivatives, ethylene / vinyl acetate copolymer, styrene / maleic anhydride copolymer. Polymer, ethylene / maleic anhydride copolymer, isobutylene / maleic anhydride copolymer, polyvinylpyrrolidone, ethylene / acrylic acid copolymer, vinyl acetate / acrylic acid copolymer, carboxymethylcellulose, methylcellulose, casein, gelatin, Mention may be made of starch derivatives, arabic gum and sodium alginate. These water-soluble polymers are preferably those that do not react with isocyanate compounds or are extremely difficult to react. For example, those having a reactive amino group in the molecular chain, such as gelatin, should have no reactivity in advance. is required.

  In the present invention, the surfactant may be added to either the oil phase or the aqueous phase, but it is easier to add to the aqueous phase because of its low solubility in organic solvents. The addition amount is preferably 0.1 to 5% by mass, particularly 0.5 to 2% by mass, based on the mass of the oil phase. In general, surfactants used for emulsification and dispersion are considered to be superior surfactants having a relatively long-chain hydrophobic group. “Surfactant Handbook” (Nishi Ichiro et al., Sangyo Tosho (1980)), alkyl Alkali metal salts such as sulfonic acid and alkylbenzene sulfonic acid can be used.

  In the present invention, compounds such as a formalin condensate of an aromatic sulfonate and a formalin condensate of an aromatic carboxylate represented by the following general formula (A) can also be used as a surfactant (emulsification aid). .

In the general formula (A), R represents an alkyl group having 1 to 4 carbon atoms, X is SO ₃ ^- or COO ^- represents, M represents sodium atom or potassium atom, and q is an integer from 1 to 20 Represents. The compound represented by the general formula (A) is described in JP-A-6-297856.

  Moreover, the alkyl glucoside type compound shown to the following general formula (B) can be used similarly.

  In the general formula (B), R represents an alkyl group having 4 to 18 carbon atoms, and q represents an integer of 0 to 2.

  In the present invention, any surfactant may be used alone, or two or more kinds may be used in combination as appropriate. Such surfactants are described in publications such as JP-A-6-297856 and JP-A-7-116501, and the use method thereof can also be referred to.

  A mixed solution (oil phase) of the diazo compound (or electron donating dye precursor), a solution having a high boiling point solvent and the like and the isocyanate composition according to the present invention is used as an aqueous solution comprising a surfactant and a water-soluble polymer ( To the aqueous phase). At this time, the aqueous solution is emulsified and dispersed by addition while stirring with a high shear stirring device such as a homogenizer. After this emulsification, a polymerization reaction catalyst for an isocyanate compound is added, or the temperature of the emulsion is increased to carry out a capsule wall forming reaction.

A coupling reaction quencher can be added as appropriate to the microcapsule solution encapsulating the prepared diazo compound. Examples of the reaction quencher include hydroquinone, sodium bisulfite, potassium nitrite, hypophosphorous acid, stannous chloride and formalin. These compounds are described in JP-A-60-214992.
In general, diazo compounds often elute in the aqueous phase during the encapsulation process, but as a method for removing this, filtration, ion exchange, electrophoresis, chromatography, gel filtration, reverse osmosis Methods such as treatment, ultrafiltration treatment, dialysis treatment, and activated carbon treatment can be used. Among these, ion exchange treatment, reverse osmosis treatment, ultrafiltration treatment and dialysis treatment are preferable, and in particular, treatment with a cation exchanger and treatment with a combination of a cation exchanger and an anion exchanger are preferred. These methods are described in JP-A-61-219688.

  In the present invention, an electron accepting compound, a thermal sensitizer, a coupler, a base compound, and the like can be added to the heat sensitive recording layer. These can be mixed as appropriate and added separately after being emulsified and dispersed, or solid dispersed and atomized, or mixed as appropriate, and then added after being emulsified and dispersed, solid dispersed and atomized. In the emulsifying and dispersing method, these compounds are dissolved in an organic solvent, and a water-soluble polymer aqueous solution is added while stirring with a homogenizer or the like. In promoting the formation of fine particles, it is preferable to use the aforementioned hydrophobic organic solvent, surfactant, and water-soluble polymer.

  In order to solid-disperse couplers, base compounds, electron accepting compounds, thermal sensitizers, etc., these powders are put into a water-soluble polymer aqueous solution and made into fine particles using a known dispersing means such as a ball mill. be able to. The microparticulation is preferably performed so as to obtain a particle diameter satisfying the characteristics required for the heat-sensitive recording material such as heat sensitivity, storage stability, transparency of the recording layer, and production suitability and the production method thereof.

The above-mentioned microcapsule liquid and preparation liquids such as a heat sensitizer, an electron accepting compound, a coupler and a base compound are mixed at an appropriate ratio and coated on a support. In general, 1 to 10 moles, and preferably 2 to 6 moles of coupler are suitable for 1 mole of diazo compound. The optimum addition amount of the basic compound varies depending on the basic strength, but is generally 0.5 to 5 mol of the diazo compound.
The electron-accepting compound (developer) is generally added in the range of 0.5 to 30 mol, preferably in the range of 1 to 20 mol, per 1 mol of the electron-donating dye precursor. More preferably, it is added in the range of 3 to 15 mol. The thermal sensitizer is generally added within a range of 0.1 to 20 mol with respect to the electron donating dye precursor, but is preferably added within a range of 0.5 to 10 mol.

  As the support on which these coating solutions are applied, known materials can be used as the support for the heat-sensitive recording material. Examples thereof include paper, coated paper obtained by applying clay or the like on paper, laminated paper obtained by laminating polyethylene, polyester or the like on paper, synthetic paper, plastic film such as polyethylene terephthalate, polyimide, or triacetyl cellulose. Examples of the transparent support include the polyethylene terephthalate, triacetyl cellulose, and plastic films such as polystyrene, polypropylene, and polyethylene.

  In the present invention, a protective layer may be provided on the heat-sensitive recording layer in order to further improve light fastness and the like. In the multicolor thermosensitive recording material, an intermediate layer may be provided between the thermosensitive recording layers in order to further improve the color reproducibility. As a material for the layer used in these, an emulsion (latex) of a water-soluble polymer compound or a hydrophobic polymer compound is preferable.

  The multicolor thermosensitive recording material and recording method thereof of the present invention will be described. First, the outermost heat-sensitive recording layer containing the diazo compound (first heat-sensitive recording layer, usually yellow color-developing layer) is developed by low-energy heat recording, and then the diazo compound contained in the heat-sensitive recording layer is changed. The entire surface is irradiated with a light source that emits light in the absorption wavelength range, and the diazo compound remaining in the uppermost thermosensitive recording layer is photolyzed.

  Next, a second heat-sensitive recording layer (second heat-sensitive recording layer) containing a diazo compound having a higher energy than the previous time and having a light absorption wavelength range different from that of the absorption wavelength range of the diazo compound contained in the first layer. The recording layer (usually the magenta coloring layer) is colored, and then the whole surface is irradiated again with a light source that emits light in the absorption wavelength range of the diazo compound, thereby remaining in the second heat-sensitive recording layer. Photolyze diazo compounds. Finally, the layer (third layer) containing the electron donating dye precursor of the innermost layer (third heat-sensitive recording layer, usually cyan coloring layer) is developed with higher energy to complete image recording.

  In the above case, it is preferable that the outermost layer and the second layer are transparent heat-sensitive layers because each color is brilliant. In the present invention, a multicolor image can also be obtained by using a transparent support as the support and applying any one of the three layers to the back of the transparent support. In this case, the uppermost heat-sensitive layer on the side opposite to the image viewing side does not need to be transparent.

  As a light source used for the photolysis of the diazo compound, an ultraviolet lamp is usually used. An ultraviolet lamp is a fluorescent tube in which mercury vapor is filled in a tube, and fluorescent tubes having various emission wavelengths can be obtained depending on the type of phosphor applied to the inner wall of the tube.

  In a multicolor thermosensitive recording material, the third thermosensitive recording layer can be formed by combining an appropriate diazo compound and a coupler compound.

  Examples are shown below, but the present invention is not limited thereto. In the examples, “parts” and “%” all represent “parts by mass” and “% by mass”.

[Synthesis Example 1]
A specific example of the compound of the general formula (I) (the above No. 1-1) 11.1 g and mercaptoethanol 0.078 g were mixed in tetrahydrofuran 19 g and refluxed under a nitrogen stream, and then 2,2′-azobis ( A solution prepared by dissolving 0.015 g of 2,4-dimethylvaleronitrile) in 1 g of tetrahydrofuran was added dropwise. After refluxing for 5 hours, 0.008 g of 2,2′-azobis (2,4-dimethylvaleronitrile) was added, and after refluxing for another 2.5 hours, the reaction mixture was poured into methanol for reprecipitation. It was. This precipitate was vacuum-dried to obtain 10.8 g of a white solid. The number average molecular weight (in terms of polystyrene) of this polymer was 3,500.

[Synthesis Example 2]
A specific example of the compound of the general formula (I) (the above No. 1-3) 12.4 g and mercaptoethanol 0.087 g were mixed in tetrahydrofuran 19 g and refluxed under a nitrogen stream, and then 2,2′-azobis ( A solution prepared by dissolving 0.015 g of 2,4-dimethylvaleronitrile) in 1 g of tetrahydrofuran was added dropwise. After refluxing for 4 hours, 0.015 g of 2,2′-azobis (2,4-dimethylvaleronitrile) was added and the mixture was further refluxed for 2.5 hours, and then the reaction mixture was poured into ethanol for reprecipitation. It was. This precipitate was vacuum-dried to obtain 11.1 g of a white solid. The number average molecular weight (in terms of polystyrene) of this polymer was 5700.

[Synthesis Example 3]
6.88 g of a specific example of the compound of general formula (I) (said No. 1-5) and 0.049 g of mercaptoethanol were mixed with 11 g of methyl ethyl ketone, heated to an external temperature of 80 ° C. under a nitrogen stream, A solution prepared by dissolving 0.007 g of 2′-azobis (2,4-dimethylvaleronitrile) in 1 g of methyl ethyl ketone was added dropwise. After heating at an external temperature of 80 ° C. for 7 hours, a solution of 0.002 g of 2,2′-azobis (2,4-dimethylvaleronitrile) in 1 g of methyl ethyl ketone was added, stirred for 3 hours, and then further 2,2′-azobis ( 2,4-dimethylvaleronitrile) 0.007 g of methyl ethyl ketone 1 g solution was added and stirred for 2 hours, and then the reaction mixture was poured into acetonitrile for reprecipitation. This precipitate was vacuum-dried to obtain 5.71 g of a white solid. The number average molecular weight (in terms of polystyrene) of this polymer was 25000.

[Synthesis Example 4]
7.7 g of the compound of general formula (I) (above No. 1-2) and 0.052 g of mercaptoethanol were mixed with 10 g of methyl ethyl ketone and heated to an external temperature of 80 ° C. under a nitrogen stream. A solution prepared by dissolving 0.01 g of 2′-azobis (2,4-dimethylvaleronitrile) in 1 g of methyl ethyl ketone was added dropwise. After heating at an external temperature of 80 ° C. for 3 hours, 0.01 g of 2,2′-azobis (2,4-dimethylvaleronitrile) in 1 g of methyl ethyl ketone was added, and the mixture was further stirred for 4.5 hours. The mixture was poured into a mixed solvent of methanol and methanol for reprecipitation. This precipitate was vacuum-dried to obtain 6.4 g of a white solid. The number average molecular weight (in terms of polystyrene) of this polymer was 6100.

[Synthesis Example 5]
14 g of the compound of general formula (I) (No. 1-6) and 0.095 g of mercaptoethanol were mixed with 13 g of methyl ethyl ketone and heated to an external temperature of 80 ° C. under a nitrogen stream, and then 2,2 ′ -A solution obtained by dissolving 0.016 g of azobis (2,4-dimethylvaleronitrile) in 1 g of methyl ethyl ketone was added dropwise. After heating at an external temperature of 80 ° C. for 2 hours, 0.01 g of 2,2′-azobis (2,4-dimethylvaleronitrile) in 1 g of methyl ethyl ketone was added and stirred for 2 hours, and then 2,2′-azobis ( 2,4-dimethylvaleronitrile) 0.01 g of methyl ethyl ketone 1 g solution was added and stirred for 3.5 hours, and then the reaction mixture was poured into acetonitrile for reprecipitation. This precipitate was vacuum-dried to obtain 12.7 g of a white solid. The number average molecular weight (in terms of polystyrene) of this polymer was 6200.

[Example 1]
5 parts of the polymerization compound of Synthesis Example 1 was mixed with 20 parts of ethyl acetate, refluxed for 30 minutes under a nitrogen stream, and then ethyl acetate was distilled off. Returned to a temperature of 50 ° C., 6.67 parts of xylylene diisocyanate / trimethylolpropane adduct (“Takenate D110N” manufactured by Mitsui Takeda Chemical Co., Ltd., 75% ethyl acetate solution) as a polyvalent isocyanate compound, and dry ethyl acetate 10 parts were added and stirred at an external temperature of 60 ° C. for 5 hours. Ethyl acetate was added thereto to obtain a 40% solution of the isocyanate composition (1) of the present invention.

[Example 2]
In Example 1, a 40% solution of the isocyanate composition (2) of the present invention was obtained in the same manner as in Example 1, except that the polymerization compound of Synthesis Example 2 was used instead of the polymerization compound of Synthesis Example 1. .

[Example 3]
In Example 1, a 40% solution of the isocyanate composition (3) of the present invention was obtained in the same manner as in Example 1 except that the polymerization compound of Synthesis Example 3 was used instead of the polymerization compound of Synthesis Example 1. .

[Example 4]
In Example 1, a 40% solution of the isocyanate composition (4) of the present invention was obtained in the same manner as in Example 1 except that the polymerization compound of Synthesis Example 4 was used instead of the polymerization compound of Synthesis Example 1. .

[Example 5]
In Example 1, a 40% solution of the isocyanate composition (4) of the present invention was obtained in the same manner as in Example 1 except that the polymerization compound of Synthesis Example 5 was used instead of the compound polymerization of Synthesis Example 1. .

[Example 6]
(Preparation of diazonium salt-encapsulated microcapsule solution)
As a diazonium salt compound, 3.5 parts of the following compound (A-1) having a maximum absorption wavelength of decomposition at 420 nm and 0.9 part of compound (A-2) are dissolved in 16.4 parts of ethyl acetate, 7.3 parts of isopropyl biphenyl which is a boiling point solvent and 2.5 parts of diphenyl phthalate were added and heated to mix uniformly.

In the above mixture, 4.5 parts of xylylene diisocyanate / trimethylolpropane adduct (“Takenate D110N”, 75% ethyl acetate solution manufactured by Mitsui Takeda Chemical Co., Ltd.) and JP-A-5-233536 are used as capsule wall materials. The test was carried out on 6.9 parts of a mixture comprising 4.5 parts of a 30% ethyl acetate solution of xylylene diisocyanate / bisphenol A adduct synthesized according to the method described in the publication (← Japanese Patent Application No. 5-233536). 2.2 parts of the isocyanate composition (1) described in Example 1 was added and stirred uniformly.
Separately, 77 parts of an 8% aqueous solution of phthalated gelatin to which 0.36 part of “ScraphAG-8” manufactured by Nippon Seika Co., Ltd. is added, and a mixture (solution) of the above diazonium salt compound is added to the homogenizer. Was emulsified and dispersed. After adding 20 parts of water to the obtained emulsified dispersion and homogenizing it, a capsule forming reaction was carried out over 3 hours with stirring at a temperature of 40 ° C. Thereafter, the liquid temperature was lowered to 35 ° C., and 4.1 parts of ion exchange resin “Amberlite IRA68” (manufactured by Organo) and 8.2 parts of “Amberlite IRC50” (manufactured by Organo) were added. Stir for 1 hour. Thereafter, the ion exchange resin was removed by filtration, and the concentration was adjusted so that the solid content concentration of the capsule liquid was 20.0%, thereby obtaining a target diazonium salt-encapsulating microcapsule liquid. The obtained microcapsules had a median diameter of 0.80 μm as a result of measurement using a particle size distribution measuring device “LA-700” manufactured by Horiba, Ltd.

[Example 7] (Preparation of microcapsule solution)
In Example 6, except that the isocyanate composition (2) described in Example 2 was used instead of the isocyanate composition (1) of Example 1 as the capsule wall material used for the preparation of the microcapsule solution. In the same manner as in Example 6, a diazonium salt-encapsulating microcapsule solution was obtained. The average particle size of the microcapsules was 0.79 μm.

[Example 8] (Preparation of microcapsule solution)
In Example 6, except that the isocyanate composition (3) described in Example 3 was used instead of the isocyanate composition (1) of Example 1 as the capsule wall material used for the preparation of the microcapsule solution. In the same manner as in Example 6, a diazonium salt-encapsulating microcapsule solution was obtained. The average particle size of the microcapsules was 0.77 μm.

[Example 9] (Preparation of microcapsule solution)
In Example 6, except that the isocyanate composition (4) described in Example 4 was used instead of the isocyanate composition (1) of Example 1 as the capsule wall material used for the preparation of the microcapsule solution. In the same manner as in Example 6, a diazonium salt-encapsulating microcapsule solution was obtained. The average particle size of the microcapsules was 0.76 μm.

[Example 10] (Preparation of microcapsule solution)
In Example 6, except that the isocyanate composition (5) described in Example 5 was used instead of the isocyanate composition (1) of Example 1 as the capsule wall material used for the preparation of the microcapsule solution. In the same manner as in Example 6, a diazonium salt-encapsulating microcapsule solution was obtained. The average particle size of the microcapsules was 0.77 μm.

[Example 11]
(Preparation of coupler emulsion dispersion)
As coupler compounds, 2,5-di-n-heptyloxyacetanilide 2.4 parts, triphenylguanidine 2.5 parts, 4- (2-ethylhexyloxy) phenylsulfonamide 3.3 parts, 4-n-pentyloxy 1.7 parts of phenylsulfonamide and 5.0 parts of 4,4 ′-(m-phenylenediisopropylidene) diphenol were dissolved in 8.0 parts of ethyl acetate to obtain “Pionin A41C” (Takemoto Yushi Co., Ltd.). (Product made) After adding 1.0 part, it heated and mixed uniformly. This mixture was added to 75.0 parts of a separately prepared gelatin (“# 750 gelatin” manufactured by Nitta Gelatin Co., Ltd.) 10% aqueous solution and emulsified and dispersed at a temperature of 40 ° C. using a homogenizer. The remaining ethyl acetate was evaporated from this emulsified dispersion, and the concentration was adjusted so that the solid content concentration was 26.5%.
Further, 100 parts of the coupler emulsified dispersion was prepared by adjusting SBR latex (trade name “SN-307”, 48% dispersion manufactured by Sumika ABS Latex Co., Ltd.) to a concentration of 26.5% 9 Part was added and stirred uniformly to obtain the desired coupler emulsified dispersion.

(Preparation of coating solution for thermosensitive recording layer (A))
The diazonium salt-encapsulating microcapsule liquid described in Example 6 and the above-mentioned coupler emulsified dispersion are mixed so that the mass ratio of the diazonium salt compound / coupler compound is 1 / 3.2 to obtain a target thermosensitive recording layer ( A) Coating solution was obtained.

(Preparation of coating solution for protective layer (D))
An aqueous solution of itaconic acid-modified polyvinyl alcohol having a concentration of 5.0% (“KL-318” manufactured by Kuraray Co., Ltd.) in an aqueous solution of zinc stearate having a concentration of 20.5% (“Hydrin” manufactured by Chukyo Yushi Co., Ltd.) F115 ") 2.0 parts, 8.4 parts of a 2% aqueous solution of the following compound (D-1), 8.0 parts of a fluorine-based mold release agent (" ME-313 "manufactured by Daikin), wheat starch 0.5 part (“KF-4” manufactured by Kashiwajima Starch Co., Ltd.) was added and stirred uniformly. This is called “mother liquor”.

_{C 12 H 25 O- (C 2} H 4 O) 10 -H compound (D-1)

Separately, 12.5 parts of ion-exchanged 20% aqueous solution of kao gloss (manufactured by Shiraishi Kogyo Co., Ltd.), 0.06 part of “Poise 532A” (manufactured by Kao Corporation), “Hydrin Z-7” (Chukyo Yushi ( 1.87 parts, 10% concentration polyvinyl alcohol (“PVA105” manufactured by Kuraray Co., Ltd.) 1.25 parts aqueous solution, and 2% concentration sodium dodecyl sulfonate aqueous solution 0.39 parts mixed, Fine dispersion was performed using a Dynomill. This dispersion is called “pigment liquid”.
To 80 parts of the “mother liquid”, 4.4 parts of the “pigment liquid” was added and stirred for 30 minutes or more. Thereafter, 2.8 parts of “Wetmaster 500” (manufactured by Toho Chemical Co., Ltd.) was added, and the mixture was further stirred for 30 minutes or more to obtain the intended coating solution for the protective layer (D).

(Preparation of thermal recording material)
Using a wire bar, the thermal recording layer (A) coating solution and the protective layer (D) coating solution are applied in this order on the surface of a photographic paper support in which polyethylene is laminated on fine paper and dried. A heat-sensitive recording material (1) of the present invention was obtained. In the above coating, the coating amounts as the solid content were 4.5 g and 1 g per 1 m ² , respectively.

(Thermal recording and evaluation test)
Using the thermal head “KST type” manufactured by Kyocera Corporation, the thermal recording characteristics of the thermal recording material (1) were evaluated as follows.
(1) The applied power and pulse width to the thermal head were set so that the recording energy per unit area was 34 mJ / mm ^2, and the yellow image was recorded by printing on the thermal recording material.
(2) The recording material was irradiated with an ultraviolet lamp having an emission center wavelength of 420 nm and an output of 40 W for 10 seconds to fix the image in the unprinted area. The color density of the yellow image was determined by measuring the optical reflection density of the color development portion using a Macbeth densitometer “RD918 type”, and the result is shown in Table 1 below as the color density.
(3) Shelf life (raw storage stability) was evaluated by storing the obtained thermosensitive recording material in a constant temperature and humidity chamber maintained at a temperature of 40 ° C. and a relative humidity of 90% for 24 hours, and then fixing the non-printed area. Then, the optical reflection density of the background portion was measured, and the result is shown as the fog density in Table 1 below.

[Example 12]
In Example 11, the diazonium salt-encapsulated microcapsule liquid described in Example 7 was used instead of the diazonium salt-encapsulated microcapsule liquid described in Example 6 used in the preparation of the coating solution for the thermosensitive recording layer (A). Except for this, the heat-sensitive recording material (2) of the present invention was produced in the same manner as in Example 11.

[Example 13]
In Example 11, the diazonium salt-encapsulated microcapsule liquid described in Example 8 was used instead of the diazonium salt-encapsulated microcapsule liquid described in Example 6 used in the preparation of the coating solution for the thermosensitive recording layer (A). Except for this, the heat-sensitive recording material (3) of the present invention was produced in the same manner as in Example 11.

[Example 14]
In Example 11, the diazonium salt-encapsulated microcapsule liquid described in Example 9 was used instead of the diazonium salt-encapsulated microcapsule liquid described in Example 6 used in the preparation of the coating solution for the thermosensitive recording layer (A). Except for this, the heat-sensitive recording material (4) of the present invention was produced in the same manner as in Example 11.

[Example 15]
In Example 11, the diazonium salt-encapsulated microcapsule liquid described in Example 10 was used instead of the diazonium salt-encapsulated microcapsule liquid described in Example 6 used in the preparation of the coating solution for the thermosensitive recording layer (A). Except for this, the heat-sensitive recording material (5) of the present invention was produced in the same manner as in Example 11.

[Comparative Example 1]
In Example 6, xylylene diisocyanate / trimethylolpropane adduct ("Takenate D110N" manufactured by Mitsui Takeda Chemical Co., Ltd.), 75% ethyl acetate was used as the capsule wall material used in (Preparation of diazonium salt-encapsulating microcapsule solution). 8.6 parts of a mixture comprising 4.5 parts of a solution and 4.5 parts of a 30% ethyl acetate solution of xylylene diisocyanate / bisphenol A adduct synthesized according to the method described in JP-A-5-233536. A diazonium salt-encapsulating microcapsule solution was prepared in the same manner as in Example 6 except that the isocyanate composition (1) described in Example 1 was not added.
Next, in Example 11, instead of the diazonium salt-encapsulating microcapsule liquid described in Example 6 used in (Preparation of coating solution for thermosensitive recording layer (A)), the diazonium salt-encapsulating microcapsule liquid obtained above was used. A comparative heat-sensitive recording material was produced in the same manner as in Example 11 except that was used. The average particle size of the microcapsules was 1.0 μm.

[Comparative Example 2]
In Synthesis Example 1, a polymer was obtained in the same manner as in Synthesis Example 1 except that methyl methacrylate was used instead of Compound Example (No. 1-1) of General Formula (I). The number average molecular weight (in terms of polystyrene) of this polymer was 11,000.
Next, in Example 1, a 40% solution of the isocyanate composition was obtained in the same manner as in Example 1 except that the polymer was used instead of the polymerization compound of Synthesis Example 1.
Next, in Example 6, except that the above isocyanate composition was used instead of the isocyanate composition (1) of Example 1 as the capsule wall material used for the preparation of the diazonium salt-encapsulating microcapsule solution, In the same manner as in Example 6, a diazonium salt-encapsulating microcapsule solution was obtained. The average particle size of the microcapsules was 0.82 μm.
Furthermore, in Example 11, instead of the diazonium salt-encapsulated microcapsule liquid described in Example 6 used in the preparation of the coating solution for the thermosensitive recording layer (A), the diazonium salt-encapsulated microcapsule liquid was used. In the same manner as in Example 11, a heat-sensitive recording material of a comparative example was produced.

  For each of the heat-sensitive recording materials (Examples 12 to 15 and Comparative Examples 1 and 2) obtained above, thermal recording and an evaluation test were performed in the same manner as in Example 11, and the color density in the image area and the fog density in the background area. Was measured. The results are shown in Table 1 below.

  As is apparent from the results of Table 1 above, the heat-sensitive recording materials (Examples 11 to 15) containing microcapsules produced using the isocyanate composition according to the present invention were compared with those of Comparative Examples 1 and 2. Thus, it was found that the recording material had a high color density in the image area and a low fog density in the background area, and was excellent in color development and raw storage.

[Example 16]
(Preparation of diazonium salt-encapsulated capsule solution)
As a diazonium salt compound, 2.8 parts of the following compound (B-1) having a maximum absorption wavelength of decomposition at 365 nm, 2.8 parts of dibutyl sulfate, and 2,2-dimethoxy-1,2-diphenylethane-1-one ( 0.56 parts of “Irgacure 651” manufactured by Ciba-Geigy Co., Ltd. was dissolved in 10.0 parts of ethyl acetate. Further, 5.9 parts of isopropyl biphenyl which is a high boiling point solvent and 2.5 parts of tricresyl phosphate were added and heated to mix uniformly.

7.6 parts of xylylene diisocyanate / trimethylolpropane adduct (“Takenate D110N”, 75% ethyl acetate solution, manufactured by Mitsui Takeda Chemical Co., Ltd.) as a capsule wall material is uniformly added to the above mixture. Stir.
Separately, 64 parts of a 6% gelatin aqueous solution (trade name “MGP-9066” manufactured by Nippi Gelatin Industries Co., Ltd.) to which 2.0 parts of a 10% sodium dodecyl sulfonate aqueous solution was added were prepared, and a mixed solution of the above diazonium salt compound Was added and emulsified and dispersed using a homogenizer.

  After adding 20 parts of water to the obtained emulsion and homogenizing it, the mixture was reacted at a temperature of 40 ° C. for 30 minutes with stirring, then heated to a temperature of 60 ° C. and encapsulated for 3 hours. Thereafter, the temperature of the solution is lowered to 35 ° C., and 4.1 parts of ion exchange resin “Amberlite IRA68” (organo) and 8.2 parts of “Amberlite IRC50” (organo) are added and further stirred for 1 hour. did. Thereafter, the ion exchange resin was filtered to obtain a diazonium salt-encapsulated capsule solution. The average particle size of the microcapsules was 0.64 μm.

(Preparation of coupler emulsion dispersion)
As a coupler compound, 3.0 parts of the following compound (B-2), 8.0 parts of triphenylguanidine, 8.0 parts of 1,1- (p-hydroxyphenyl) -2-ethylhexane, 4,4 ′-( p-phenylenediisopropylidene) diphenol 8.0 parts, the following compound (B-3) 2.0 parts, and 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) 2.0 parts of butane is dissolved in 10.5 parts of ethyl acetate, and 0.48 part of tricresyl phosphate and 0.24 part of diethyl maleate, which are high-boiling solvents, and “Pionin A41C” (Takemoto Yushi Co., Ltd.) (Product made) After adding 1.27 parts, it heated and mixed uniformly. This mixture was added to 93 parts of an aqueous solution of 8% gelatin (“# 750 gelatin” manufactured by Nitta Gelatin Co., Ltd.) and emulsified and dispersed using a homogenizer. The remaining ethyl acetate was evaporated from the emulsion dispersion to obtain a coupler emulsion dispersion.

(Preparation of coating solution for thermosensitive recording layer (B))
The diazonium salt-encapsulating microcapsule liquid and the coupler emulsified dispersion are mixed so that the mass ratio of the diazonium salt compound / coupler compound is 1 / 3.2 to obtain a desired coating solution for the thermosensitive recording layer (B). Got.

(Preparation of electron-donating dye precursor-encapsulated microcapsule solution)
As an electron-donating dye precursor, 3- (o-methyl-p-diethylaminophenyl) -3- (1'-ethyl-2-methylindol-3-yl) phthalide (0.39 parts), an ultraviolet absorber at 285 nm 0.19 part of 2-hydroxy-4-methoxybenzophenone having the maximum absorption wavelength and 0.29 part of 2,5-tert-octylhydroquinone as an antioxidant are dissolved in 0.93 part of ethyl acetate, and further have a high boiling point. 0.54 part of phenethylcumene as a solvent was added and heated to mix uniformly. To this solution, 1.0 part of xylylene diisocyanate / trimethylolpropane adduct (“Takenate D110N” manufactured by Mitsui Takeda Chemical Co., Ltd.) as a capsule wall material was added and stirred uniformly.
Separately, 36.4 parts of a 6% gelatin aqueous solution (“MGP-9066” manufactured by Nippi Gelatin Industries Co., Ltd.) to which 0.07 part of a 10% sodium dodecyl sulfonate aqueous solution was added were prepared, and the above electron-donating dye was prepared. The precursor solution was added and emulsified and dispersed using a homogenizer. The emulsion dispersion thus obtained is referred to as “primary emulsion dispersion”.

  Separately, 6.0 parts of 3- (o-methyl-p-diethylaminophenyl) -3- (1'-ethyl-2-methylindol-3-yl) phthalide, 3.0 parts of 2-hydroxy-4-methoxybenzophenone In addition, 4.4 parts of 2,5-tert-octylhydroquinone is dissolved in 14.4 parts of ethyl acetate, and 8.4 parts of phenethylcumene, which is a high-boiling solvent, is added and stirred uniformly. 7.8 parts of “Takenate D110N” (manufactured by Mitsui Takeda Chemical Co., Ltd.) and 5.9 parts of methylene diisocyanate (“Millionate MR200” manufactured by Nippon Polyurethane Co., Ltd.) were added and stirred uniformly. The solution thus obtained and 1.2 parts of a 10% aqueous sodium dodecylsulfonate solution were added to the “primary emulsified dispersion” and emulsified and dispersed using a homogenizer. The liquid thus obtained is called “secondary emulsified dispersion”. After adding 60.0 parts of water and 0.4 part of diethylenetriamine to this “secondary emulsified dispersion” and homogenizing, the temperature was raised to 65 ° C. with stirring, and the encapsulation reaction was carried out over 3.5 hours. The target electron donating dye precursor-encapsulated microcapsule solution was obtained. The average particle size of the microcapsules was 1.9 μm.

(Preparation of electron-accepting compound emulsion dispersion)
30 parts of bisphenol P as an electron-accepting compound was added to 82.5 parts of a 2.0% aqueous solution of gelatin (“MGP-9066” manufactured by Nippi Gelatin Industries Co., Ltd.), and further sodium 2-ethylhexylsulfosuccinate having a concentration of 2%. 7.5 parts of an aqueous solution was added, and the resulting mixture was dispersed for 24 hours using a ball mill to prepare a dispersion. To this dispersion was added 36.0 parts of a 15% gelatin (“# 750 gelatin” manufactured by Nitta Gelatin Co., Ltd.) aqueous solution and stirred uniformly to obtain an electron-accepting compound emulsified dispersion. The average particle size of the electron-accepting compound in this dispersion was 0.5 μm.

(Preparation of coating solution for thermosensitive recording layer (C))
Next, the above-mentioned electron-donating dye precursor-encapsulated capsule liquid, the above-mentioned electron-accepting compound emulsion dispersion, a 15% gelatin (“# 750 gelatin” manufactured by Nitta Gelatin Co., Ltd.) aqueous solution, and a stilbene fluorescent whitening agent ("Whiteex-BB" manufactured by Sumitomo Chemical Co., Ltd.), the electron donor dye precursor / electron acceptor mass ratio is 1/14, the electron donor dye precursor / "# 750 gelatin" mass ratio Was 1.1 / 1, and the mass ratio of electron donating dye precursor / fluorescent brightener was 5.3 / 1 to prepare the intended coating solution for the thermosensitive recording layer (C). .

(Preparation of coating solution for intermediate layer (E))
A 14% gelatin aqueous solution (“# 750 gelatin” manufactured by Nitta Gelatin Co., Ltd.) in an aqueous solution containing 8.2 parts of a 4% boric acid aqueous solution and a 2% aqueous solution of sodium (4-nonylphenoxytrioxyethylene) butyl sulfonate 2 parts and 7.5 parts of 2% aqueous solution of the following compound (E-1) were added and stirred uniformly to prepare a coating solution for the desired intermediate layer (E).

(CH ₃ CH ₂ SO ₂ CH ₂ CONHCH ₂ ) ₂ -Compound (E-1)

(Production of multicolor thermal recording material)
Using a wire bar on the surface of a photographic paper support in which polyethylene is laminated on high-quality paper, the above-mentioned coating solution for thermal recording layer (C), coating solution for intermediate layer (E), thermal recording layer (B) The coating solution for coating, the coating solution for intermediate layer (E), the coating solution for heat-sensitive recording layer (A) described in Example 11 and the coating solution for protective layer (D) were applied in this order and dried. A multicolor thermosensitive recording material was prepared. In the above coating, the coating amount as a solid content was 9 g, 3 g, 8 g, 3 g, 4.5 g, and 1 g, respectively, per 1 m ² .

(Thermal recording and evaluation test)
Using the thermal head “KST type” manufactured by Kyocera Corporation, the thermal recording characteristics of the multicolor thermal recording material were evaluated as follows.
(1) The applied power and pulse width to the thermal head were adjusted so that the recording energy per unit area would be 35 mJ / mm ^2, and the yellow image was recorded by printing on the thermal recording material. (2) The recording material is irradiated with an ultraviolet lamp having an emission center wavelength of 420 nm and an output of 40 W for 10 seconds. (3) The applied power and pulse to the thermal head again so that the recording energy per unit area becomes 80 mJ / mm ^2. The width was adjusted and printed, and a magenta image was recorded. (4) Irradiation with an ultraviolet lamp with an emission center wavelength of 365 nm and an output of 40 W for 15 seconds. (5) Again, the applied power and pulse width to the thermal head are set so that the recording energy per unit area is 140 mJ / mm ^2. A cyan image was recorded by adjusting and printing.
As a result, in addition to the yellow, magenta, and cyan color images, the print portion where the yellow and magenta records overlap is red, the print portion where the magenta and cyan overlap is blue, and the yellow and cyan overlap. Was colored green, and the image portion where the yellow, magenta and cyan prints overlapped was colored black. The unprinted portion was grayish white. The optical reflection density of each colored portion of yellow, magenta, and cyan was measured with a “Macbeth RD918 type” densitometer.
The shelf life (raw preservation) was evaluated by allowing the obtained multicolor thermosensitive recording material to stand for 24 hours in a constant temperature and humidity chamber maintained at a relative humidity of 90% at a temperature of 40 ° C. The reflection density was measured.

[Example 17]
In Example 16, the diazonium salt-encapsulated capsule liquid described in Example 7 (← 12) was used as the diazonium salt-encapsulated capsule liquid used in the coating solution for the heat-sensitive recording layer (A). Thus, a multicolor thermosensitive recording material was obtained. This heat-sensitive recording material was also heat-recorded in the same manner as in Example 16, and the color density in the print area and the fog density in the non-print area were measured. The results are shown in Table 2 below.

  As is apparent from the results in Table 2 above, the multicolor thermosensitive recording materials (Examples 16 to 17) containing microcapsules produced using the isocyanate composition according to the present invention were each colored in yellow, magenta and cyan. It was found that this is a multicolor heat-sensitive recording material having a high color density in the image area and a low fog density in the background area, and excellent in color development and raw storage.

Claims (10)

  (A) a compound obtained by radical polymerization of a polymerizable monomer containing a monomer having at least a mesogenic group in the presence of a chain transfer agent having active hydrogen; and (B) a polyfunctional isocyanate having two or more isocyanate groups in the molecule. An isocyanate composition comprising a reaction product of The isocyanate composition according to claim 1, wherein the monomer having a mesogenic group is a compound represented by the following general formula (I).

[In the above formula (I), R ¹ represents a hydrogen atom or a methyl group, and G ¹ represents —COO—, —CO · N (R ³ ) —, or —Ar—G ² —. Here, R ³ represents a hydrogen atom, an alkyl group, or an aryl group, Ar represents an arylene group, and G ² represents a single bond, —O—, —COO—, —O · CO—, —O. · COO -, - CO · N (R 4) -, or -N represents (R ⁵⁾ · CO-, wherein R ⁴ and R ⁵ independently represents a hydrogen atom, or an alkyl group. A ¹ represents a single bond or -L ¹ -G ^3- . Here, L ¹ represents an alkylene group or a group having a divalent functional group in the alkylene chain, and G ³ represents a single bond, —O—, —COO—, —O · CO—, —O ·. COO—, —CO · N (R ⁶ ) —, or —N (R ⁷ ) —CO— is represented, and each of R ⁶ and R ⁷ independently represents a hydrogen atom or an alkyl group. M represents a mesogenic group, and R ² represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, an alkoxycarbonyloxy group, a carbamoyl group, an acylamino group, or a cyano group. ]   In a microcapsule having a polyurethane and / or urea wall, the capsule wall contains a polymerizable monomer containing at least a monomer having a mesogen group in the presence of a chain transfer agent having active hydrogen via a covalent bond. A microcapsule characterized by containing. The microcapsule according to claim 3, wherein the monomer having a mesogenic group is a compound represented by the following general formula (I).

[In the above formula (I), R ¹ represents a hydrogen atom or a methyl group, and G ¹ represents —COO—, —CO · N (R ³ ) —, or —Ar—G ² —. Here, R ³ represents a hydrogen atom, an alkyl group, or an aryl group, Ar represents an arylene group, and G ² represents a single bond, —O—, —COO—, —O · CO—, —O. · COO -, - CO · N (R 4) -, or -N represents (R ⁵⁾ · CO-, wherein R ⁴ and R ⁵ independently represents a hydrogen atom, or an alkyl group. A ¹ represents a single bond or -L ¹ -G ^3- . Here, L ¹ represents an alkylene group or a group having a divalent functional group in the alkylene chain, and G ³ represents a single bond, —O—, —COO—, —O · CO—, —O ·. COO—, —CO · N (R ⁶ ) —, or —N (R ⁷ ) —CO— is represented, and each of R ⁶ and R ⁷ independently represents a hydrogen atom or an alkyl group. M represents a mesogenic group, and R ² represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, an alkoxycarbonyloxy group, a carbamoyl group, an acylamino group, or a cyano group. ]   A microcapsule having a polyurethane and / or urea wall, characterized in that the isocyanate compound used in the microcapsule produced using an isocyanate compound contains at least the isocyanate composition according to claim 1 or 2.   A recording material comprising a recording layer comprising the microcapsule according to claim 3.   The microcapsule according to any one of claims 3 to 5, wherein the microcapsule encapsulates a diazonium salt compound or an electron-donating dye precursor.   A thermosensitive recording material comprising a microcapsule encapsulating a diazonium salt compound and a coupler, or a microcapsule encapsulating an electron donating dye precursor and a thermosensitive recording layer containing a developer on a support, the microcapsule A heat-sensitive recording material, wherein the microcapsule according to claim 7.   Cyan, magenta, and yellow heat-sensitive recording layers are provided on the support, and each heat-sensitive recording layer includes a microcapsule and a coupler containing a diazonium salt compound, or a microcapsule containing an electron-donating dye precursor and a developer. A multicolor thermosensitive recording material comprising an agent, wherein at least one of the microcapsules is the microcapsule according to claim 7.   In the manufacturing method of the microcapsule using an isocyanate compound, the isocyanate compound to be used contains the isocyanate composition of Claim 1 or 2 at least, The manufacturing method of the microcapsule which has a polyurethane and / or urea wall characterized by the above-mentioned.