JPH08259486A - Alchol compound, isocyanate prepolymer, heat responding microcapsule, heat-sensitive recording material and multi-color heat-sensitive recording material using the same - Google Patents

Abstract

PURPOSE: To obtain a new alcohol compound capable of extremely reducing the water content of a wall of a heat-responding microcapsule and lowering humidity dependence of sensitivity, useful as a raw material for an isocyanate prepolymer constituting a microcapsule wall. CONSTITUTION: This compound is shown by the formula (R<1> to R<3> are each an aryl, an alkyl or a heterocyclic group; R<4> to R<6> are each H or an alkyl; R<7> to R<10> are each R<4> , a halogen, an alkenyl, an alkoxy or an aryl) such as 1,1-bis [4-(2-hydroxy-3-phenoxypropoxy)phenyl]-1-(4- 2-[4-(2-hydroxy-3- phenoxypropoxy)phenyl]propan-2-yl}phenyl]ethane. The example compound is obtained by reacting 4,4'-(1- 4-(4-hydroxyphenyl)-1- methylethyl]phenyl}ethylidene)bisphenol with glycidyl phenyl ether.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel isocyanate prepolymer useful for forming a polyurethane resin used in adhesives, paints, etc., a novel alcohol compound advantageously used therein, and a thermal recording material. The present invention relates to a thermoresponsive microcapsule using the isocyanate prepolymer, a thermosensitive recording material using the microcapsule, and a multicolor thermosensitive recording material.

[0002]

2. Description of the Related Art A heat-sensitive recording material which is widely used as a recording medium for facsimiles, printers and the like mainly uses a material obtained by applying a solid dispersion of an electron-donating dye precursor on a support and drying it. The recording method using the electron-donating dye precursor has the advantage that the material is easily available and exhibits a high color density and a high color developing speed, but it is easy to develop color due to the adhesion of a solvent and the like, and there is a problem with the storage stability of the recorded image. And many improvements have been considered.

As one method for improving the storability of a recorded image, a method of enhancing the storability of an image by encapsulating an electron-donating dye precursor in a microcapsule and forming a dye in the microcapsule. Is proposed. With this method, high image stability can be obtained.

As a heat-sensitive recording material other than the above, so-called diazo type heat-sensitive recording materials utilizing a diazonium salt compound have also been studied. This diazonium salt compound reacts with a phenol derivative or a compound having an active methylene group (coupler) to form a dye, but it also has photosensitivity and loses its activity upon irradiation with light. Applying these properties, a photo-fixing type heat-sensitive recording material has been proposed which is capable of thermally reacting a diazo compound and a coupler to form an image, and then fixing by irradiating light (Koji Sato et al. The Institute of Electronics Engineers, "11th
Vol. 4, No. 4 (1982), pages 290-296, etc.).

However, since the recording material using the diazonium salt compound has high chemical activity, the diazonium salt compound and the coupler gradually react with each other even at a low temperature, resulting in a short shelf life (shelf life). there were. As one solution to this, a method of encapsulating a diazonium salt compound in a microcapsule and isolating it from a coupler, water, and a basic compound has been proposed (Toshimasa Usami et al., "Electrophotographic Society", Vol. 26, Vol. 2 (1987), 115
~ 125).

As one of the fields of application of the heat-sensitive recording material, multicolor heat-sensitive recording material has been attracting attention. It has been said that it is more difficult to reproduce a multicolor image by thermal recording than in an electrophotographic recording method or an inkjet method, but in this respect, it has already been possible to mainly use an electron-donating dye precursor and a developer on a support. It has been found that a multicolor thermosensitive recording material can be obtained by laminating two or more thermosensitive coloring layers each containing a thermosensitive coloring layer as a component or a diazonium salt compound and a coupler that reacts with the diazonium salt compound to develop a color when heated. ing.

Conventionally, in order to include an electron-donating dye precursor or a diazonium salt compound in a microcapsule, generally, these compounds are dissolved in an organic solvent (oil phase),
This is added to an aqueous solution of a water-soluble polymer (aqueous phase) and emulsified and dispersed. At this time, a polymer wall is formed at the interface between the organic solvent phase and the water phase by adding a monomer or a prepolymer as a wall material to either or both of the organic solvent phase side and the water phase side to form microcapsules. can do. For these methods, see "Microcapsules"
(Asamu Kondo, Nikkan Kogyo Shimbun (1970)) and "Microcapsules" (Tamotsu Kondo et al., Sankyo Publishing (1977)). As the microcapsule wall to be formed, various materials such as gelatin, alginate, celluloses, polyurea, polyurethane, melamine resin and nylon can be used. In particular, polyurea and urethane resins are suitable for designing a heat-sensitive recording material because the substance permeability of the capsule wall largely changes before and after the glass transition temperature thereof, that is, the capsule wall exhibits thermal responsiveness.

As a method for producing microcapsules having a polyurethane or polyurea wall, first, a diazonium salt or an electron-donating dye precursor is dissolved in an organic solvent, a polyvalent isocyanate prepolymer is added thereto, and this organic phase solution is added. Emulsify in aqueous solution of water-soluble polymer. afterwards,
A method of forming a capsule wall by polymerizing a polyvalent isocyanate prepolymer with a compound having active hydrogen such as water by adding a catalyst for accelerating a polymerization reaction to an aqueous phase or by raising the temperature of an emulsion is known. There is.

However, according to the study of the present inventors, when the microcapsules having such a thermoresponsive wall are used as a heat-sensitive recording material, the glass transition temperature of the capsule wall depends on the water content contained in the capsule wall itself or the surroundings. It has been revealed that there is a drawback that the color density of the heat-sensitive recording material depends on the ambient temperature, because it fluctuates due to the influence of water content. In particular, when a thermosensitive recording layer of a thermo-responsive thermosensitive recording material is laminated to form a multicolor thermosensitive recording material, it is necessary to more strictly control the color developing sensitivity by color classification, and therefore the color developing sensitivity due to environmental temperature etc. Is not preferable.

[0010]

DISCLOSURE OF THE INVENTION In order to reduce the humidity dependence of the color developing sensitivity of the heat-sensitive recording material used in the thermo-responsive microcapsules, the present inventor has studied the use of an electron-donating dye precursor or a diazonium salt compound. The present invention has been achieved as a result of extensive studies on the material for forming the capsule wall of the microcapsule. That is, by using an isocyanate prepolymer obtained from the following novel alcohol compound and diisocyanate as an isocyanate prepolymer that is a material for forming a microcapsule wall polyurethane or polyurea, the water content of the wall is extremely reduced, and the sensitivity is increased. The inventors have found that the humidity dependence of is also reduced and have reached the present invention.

The present invention aims to provide novel isocyanate prepolymers useful in the formation of polyurethane resins and novel alcohol compounds advantageously used therein. Further, the present invention is a thermal response that shows high color development by contact with a coupler or a developer that can be suitably used for heat-sensitive recording materials and multicolor heat-sensitive recording materials, and has little humidity dependency of sensitivity at the time of color development. It aims at providing a sex microcapsule. Another object of the present invention is to provide a heat-sensitive recording material which has high sensitivity and has little humidity dependency of sensitivity at the time of color development. Further, the present invention is
It is an object of the present invention to provide a multicolor thermosensitive recording material having high sensitivity and having little humidity dependency of sensitivity at the time of color development.

[0012]

The present invention provides the following general formula (1):

[0013]

Embedded image

(However, R ¹ , R ² and R ³ each independently represent an aryl group, a heterocyclic group or an alkyl group,
R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or an alkyl group, and R ⁷ , R ⁸ , R ⁹ and R 6
Each ¹⁰ independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkoxy group or an aryl group. ) An alcohol compound represented by:

The alcohol compound represented by the general formula (1) has two isocyanate groups in the molecule.
Isocyanate prepolymer obtained by addition of functional isocyanate;

A microcapsule containing a diazo compound or an electron-donating dye precursor, wherein the capsule wall of the microcapsule is obtained by polymerizing the above-mentioned isocyanate prepolymer and a compound having two or more active hydrogens in the molecule. A thermoresponsive microcapsule characterized by comprising the obtained polymer;

A heat-sensitive recording material comprising a support and a microcapsule and a coupler provided on the support and containing a diazo compound, or a microcapsule containing an electron-donating dye precursor and a heat-sensitive recording layer containing a developer. There
A thermosensitive recording material characterized in that the microcapsules are the thermoresponsive microcapsules; and

A transparent support and a cyan, magenta and yellow thermosensitive recording layer provided thereon, each recording layer containing a microcapsule and a coupler containing a diazo compound, or an electron-donating dye precursor. The multicolor heat-sensitive recording material containing the microcapsules and the color developer, wherein the microcapsules are the thermoresponsive microcapsules.

Preferred embodiments of the above alcohol compound of the present invention are as follows. 1) In the general formula (1), R ¹ , R ² and R ³ each independently represent an aryl group having 6 to 16 carbon atoms or an alkyl group having 4 to 16 carbon atoms, and R ⁴ , R ⁵ and R ⁶ independently represents an alkyl group having 1 to 4 carbon atoms, and R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms. Represents a group, an alkenyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms. 2) The alcohol compound has the following general formula (2):

[0020]

Embedded image

(Wherein R ¹¹ is an unsubstituted aryl group or an aryl group having a substituent (preferably having 6 to 6 carbon atoms).
14) or a heterocyclic group. )

The preferred embodiments of the microcapsules of the present invention are as follows. 1) The capsule wall of the microcapsule is composed of the isocyanate prepolymer (alcohol compound having 3 hydroxyl groups in the molecule represented by the general formula (1) and bifunctional isocyanate having 2 isocyanate groups in the molecule). (A) and a polyfunctional isocyanate prepolymer (B) having two or more isocyanate groups in the molecule, a polyurethane / polyurea obtained by polymerization of a material. Further, the mixing ratio (A / B) of (A) and the polyfunctional isocyanate prepolymer (B) is preferably in the range of 2/8 to 10/0 by weight. 2) The compound having an active hydrogen atom used for forming the capsule wall of the microcapsule is water. 3) The diazo compound or the electron-donating dye precursor is dissolved in a high-boiling point solvent and encapsulated in microcapsules.

The thermoresponsive microcapsules of the present invention are microcapsules containing a diazo compound or an electron donating dye precursor. The heat-sensitive recording material of the present invention has a basic structure in which a heat-sensitive recording layer containing the above-mentioned microcapsules is provided on a support. Further, the multicolor heat-sensitive recording material of the present invention has a basic constitution in which a heat-sensitive recording layer containing the above-mentioned microcapsules of cyan, magenta and yellow is provided on a transparent support (black surface may be provided on the back surface of the transparent support if desired) A thermal recording layer may be provided).

The thermoresponsive microcapsules of the present invention are microcapsules containing a diazo compound or microcapsules containing an electron-donating dye precursor, and the capsule wall has three hydroxyl groups in the specific molecule. A polymer (polyurethane or polyurethane) obtained by polymerizing an adduct (an isocyanate prepolymer of the present invention) of an alcohol compound having a diamine with a bifunctional isocyanate having two isocyanate groups in the molecule with a compound having an active hydrogen such as water. Polyurethane / polyurea).

The alcohol compound having three hydroxyl groups in the molecule of the present invention is a compound represented by the following general formula (1).

[0026]

[Chemical 4]

In the general formula (1), R¹ , R² And R
³ Are each independently an aryl group, a heterocyclic group or an alkyl group.
Represents a radical. Aryl group having 6 to 16 carbon atoms, hetero
A cyclic group (eg, pyridyl) or an alkyl group having 4 to 16 carbon atoms
Group (eg, octyl, dodecyl) is preferred, especially carbon
An aryl group having 6 to 16 atoms is preferable. Also R¹ , R
² And R³ Are preferably the same groups.
R^Four , R^Five And R⁶ Represents a hydrogen atom or an alkyl group.
I forgot. An alkyl group having 1 to 4 carbon atoms is preferable, and
To R^Four , R^Five And R⁶ However, it is preferable that they are all the same group.
Good. Examples of the alkyl group include methyl and ethyl.
Propyl, propyl, isopropyl and n-butyl.
You can R⁷ , R⁸ , R⁹ And R^TenAre each German
Vertically halogen atom, alkyl group, alkenyl group, alcohol
Represents an oxy group or an aryl group. Halogen atom, carbon source
Alkenyl having 1 to 6 carbon atoms and alkeny having 1 to 6 carbon atoms
Group, an alkoxy group having 1 to 6 carbon atoms or a carbon atom
The aryl group of the formulas 6 to 14 is preferable, and further R⁷ , R ⁸ 
And R^TenAre preferably the same groups. R
⁷ , R⁸ , R⁹ And R^TenAs a group of, for example, F, Br
And halogen atoms such as I; methyl, ethyl, propyl,
Isopropyl, n-butyl, t-butyl, pentyl and
Alkyl groups such as hexyl; vinyl, allyl, butenyl and
And alkenyl groups such as pentenyl; methoxy, ethoxy,
Alkoxy such as propoxy, isopropoxy and butoxy
Si group; and phenyl, tolyl, xylyl, cumenyl,
List aryl groups such as biphenyl and naphthyl
Can be.

Further, the alcohol compound has the following general formula (2):

[0029]

Embedded image

(However, R ¹¹ (R ¹ and R in the general formula (1)
² and R ³ represent an aryl group (preferably having 6 to 14 carbon atoms) or a heterocyclic group. )

Examples of R ¹¹ are phenyl, 4-biphenyl, 2-biphenyl, naphthyl, 4-methylphenyl, 3-methylphenyl, 2-methylphenyl, 3,
4-dimethylphenyl, 4-ethylphenyl, 4-propylphenyl, 4t-butylphenyl, 3-butylphenyl, 3-hexylphenyl, 4-cumylphenyl, 2
-Methyl-4-cumylphenyl, 4-trifluoromethylphenyl, 2-methoxyphenyl, 4-ethoxyphenyl group, 4-hexyloxyphenyl, 4-phenoxyphenyl, 4-methylthiophenyl, 4-benzoylphenyl, 2-acetylphenyl , 4-chlorophenyl,
2,4-dichlorophenyl, 4-fluorophenyl, 4
Aryl groups such as -bromophenyl, 4-iodophenyl, pentafluorophenyl, 4-acetylaminophenyl, 4-methyloxycarbonylphenyl and 4-phenylaminocarbonylphenyl; and 4-pyridyl, 2.
-Furyl, furfuryl, 2-thienyl, 2-pyrrolyl,
Heterocyclic groups such as piperidino and 4-piperidyl can be mentioned.

Among these, phenyl, 2-biphenyl, 4-biphenyl, naphthyl, 4-methylphenyl,
3-methylphenyl, 2-methylphenyl, 3,4-dimethylphenyl, 4-trifluoromethylphenyl, 4
-Ethylphenyl, 4-propylphenyl, 4-butylphenyl, 4-hexylphenyl, 4-cumylphenyl, 4-methoxyphenyl, 4-ethoxyphenyl, 4
-Hexyloxyphenyl, 4-phenoxyphenyl,
4-chlorophenyl, 4-fluorophenyl, 2,4-
Dichlorophenyl, pentafluorophenyl, 4-acetylphenyl, 4-benzoylphenyl and 4-methyloxycarbonylphenyl are preferred. Especially, phenyl, 2-biphenyl, 4-biphenyl, naphthyl, 4-
Methylphenyl, 4-methoxyphenyl, 4-phenoxyphenyl, 4-cumylphenyl, 4-chlorophenyl, 4-trifluoromethylphenyl, 4-acetylphenyl, 4-benzoylphenyl and 4-methyloxycarbonylphenyl groups are preferred.

A compound known as a bifunctional isocyanate having two isocyanate groups in the molecule, which reacts with the above trivalent alcohol compound to form an adduct, can be used. Examples thereof include aromatic isocyanate prepolymers and aliphatic isocyanate prepolymers, and aromatic isocyanate prepolymers are particularly preferable. Specifically, the following can be mentioned.

M-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-
4,4'-diisocyanate, 3,3'-dimethoxy-
Biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, xylylene-1,3-
Diisocyanate, 4-chloroxylylene-1,3-diisocyanate, 2-methylxylylene-1,3-diisocyanate, 4,4'-diphenylpropane diisocyanate, 4,4'-diphenylhexafluoropropane diisocyanate, 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 (isocyanatomethyl) cyclohexane and 1,3
-Bis (isocyanatomethyl) cyclohexane. Among these, 2,4-tolylene diisocyanate, 2,6
-Tolylene diisocyanate, xylylene-1,4-diisocyanate and xylylene-1,3-diisocyanate are preferred, and xylylene-1,4-diisocyanate and xylylene-1,3-diisocyanate are particularly preferred.

The capsule wall obtained by using the (polyfunctional) isocyanate prepolymer of the present invention obtained from the alcohol compound having three hydroxyl groups in the molecule represented by the above general formula (1) and the above diisocyanate is Even if the environmental temperature changes, the moisture content in the capsule wall hardly changes, and therefore the glass transition temperature of the wall changes little. The adduct of the above-mentioned alcohol compound and a bifunctional isocyanate having two isocyanate groups in the molecule (isocyanate prepolymer of the present invention) is obtained by heating the alcohol compound and the bifunctional isocyanate in an organic solvent while stirring ( 50 to 100 ° C.) or by heating at a relatively low temperature (40 to 70 ° C.) while adding a catalyst such as stannous octylate.
Generally, 0.8 to 1.5 times the number of moles of the difunctional isocyanate as the number of moles of the hydroxyl groups of the trihydric alcohol compound are used. However, the reaction molar ratio of the compound of the general formula (I) and the bifunctional isocyanate may be changed depending on the molecular weight of the intended isocyanate prepolymer, and for example, a high molecular weight isocyanate prepolymer (isocyanate at the end is In polyurethane with groups)
If the purpose is to reduce the excess amount of the bifunctional isocyanate, it is sufficient. Two or more kinds of bifunctional isocyanate prepolymers may be used in combination.

As a raw material for the microcapsules, a polyfunctional isocyanate having two or more isocyanate groups in the molecule can be used in combination with an adduct of the alcohol compound of the present invention and a bifunctional isocyanate (isocyanate prepolymer of the present invention). Examples of the prepolymer include known compounds such as xylene diisocyanate and hydrogenated products thereof, hexamethylene diisocyanate, tolylene diisocyanate and hydrogenated products thereof, and diisocyanates such as isophorone diisocyanate. It is also possible to use these compounds as main raw materials and polyfunctional adducts with these trimers (burette or isocyanurate) and polyols such as trimethylolpropane, and formalin condensates of benzene isocyanate. it can. In particular, xylene diisocyanate and its hydrogenated product, hexamethylene diisocyanate, tolylene diisocyanate and its hydrogenated product are used as a main raw material, and these trimers (burette or isocyanurate) are adducted with trimethylol propane to provide polyfunctionality. What was done is preferable. "Polyurethane resin handbook" for these compounds
(Edited by Keiji Iwata, published by Nikkan Kogyo Shimbun (1987)).

In the present invention, as the polyfunctional isocyanate prepolymer having two or more isocyanate groups in the molecule, in addition to the isocyanate prepolymer of the present invention, a bifunctional isocyanate prepolymer represented by the following general formula is used in an appropriate ratio. Can also be used in combination. These bifunctional isocyanate prepolymers are described in Japanese Patent Application No. 5-233536 and Japanese Patent Application No. 6-4714.

[0038]

[Chemical 6]

[Wherein Ar represents an arylene group, X represents a single bond or a divalent group, R represents an alkylene group, an aralkylene group or an arylene group, and p represents an integer of 0 to 20]. ]

[0040]

[Chemical 7]

[Wherein R is a hydrogen atom or an alkyl group, X is an aryl group, an aryloxycarbonyl group, an alkoxycarbonyl group, a halogenated alkoxycarbonyl group, an aminocarbonyl group, an alkyl-substituted carbonyl group or an aryl-substituted aminocarbonyl group. , Y is an arylene group, an alkylene group or an aralkylene group, and k is 0
Or 1, p is an integer of 0 to 12, and q is 10
Represents an integer of 200. ]

The electron donating dye precursor contained in the microcapsules of the present invention is a triarylmethane compound, a diphenylmethane compound, a thiazine compound,
Examples thereof include xanthene-based compounds and spiropyran-based compounds, but triarylmethane-based compounds and xanthene-based compounds are particularly useful because of their high color density.

Specific examples of these include 3,3-bis (p-dimethylaminophenyl) -6 dimethylaminophthalide (ie, 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, 4,4'-bis (dimethylamino) benzhydrin benzyl ether, N-halophenylleuco auramine, N-2,4,5-trichlorophenyl leuco auramine, 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-diethylaminofluorane,
Benzoyl leuco methylene blue, p-nitrobenzyl leuco methylene blue, 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3,
3'-dichloro-spiro-dinaphthopyran, 3-benzylpyrodinaphthopyran, 3-propyl-spiro-dibenzopyran and the like can be mentioned.

Examples of the electron-accepting compound (developing agent (not included in the microcapsule)) used in combination with the above-mentioned electron-donating dye precursor include phenol derivatives, salicylic acid derivatives, hydroxybenzoic acid esters and the like. 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 (te
rt-Butyl) salicylic acid and its polyvalent metal salts, 3-
Examples include α, α-dimethylbenzyl salicylic acid and its polyvalent metal salts, butyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, 2-ethylhexyl p-hydroxybenzoate, p-phenylphenol and p-cumylphenol. be able to. In the present invention, two or more of these electron-accepting compounds can be used in combination at any ratio.

A sensitizer for promoting the reaction is preferably added to the heat-sensitive recording layer composed of the electron-donating dye precursor and the electron-accepting compound. As the sensitizer, a low-melting-point organic compound having an aromatic group and a polar group in the molecule is preferable. Specific examples thereof include benzyl p-benzyloxybenzoate, 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)
Examples thereof include ethane, 1-phenoxy-2- (p-ethylphenoxy) ethane, 1-phenoxy-2- (p-chlorophenoxy) ethane and p-benzylbiphenyl. In the present invention, two or more kinds of these sensitizers may be used together in an arbitrary ratio.

As the diazonium salt compound contained in the microcapsules of the present invention, known compounds can be used. The diazonium salt compound is represented by the following general formula: ArN ₂ X ⁻ [wherein Ar represents an aryl group and X ⁻ represents an acid anion. ] The compound represented by these.

The above diazonium salt compound reacts with a phenol compound or a compound having active methylene,
It forms so-called dyes and also light (generally UV)
It is decomposed by irradiation, denitrified and loses its activity. Specific examples of the diazonium salt include 2,5-dibutoxy-4-morpholinobenzenediazonium and 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-tolylthiobenzenediazonium, 2,5-dibutoxy-4-chlorobenzenethiodiazonium, 3- (2-octyloxyethoxy) -4-morpholin Nobenzenediazonium, 4-
Mention may be made of salts of N, N-dihexylamino-2-hexyloxybenzenediazonium and 4-N-hexyl-N-tolylamino-2-hexyloxybenzenediazonium.

The acid anion of the diazonium salt compound includes
Hexafluorophosphate salt, tetrafluoroborate salt, 1,5-naphthalene sulfonate salt, perfluoroalkyl carbonate salt, perfluoroalkyl sulfonate salt, zinc chloride salt, tin chloride salt and the like can be used. Hexafluorophosphate salts, tetrafluoroborate salts, and 1,5-naphthalene sulfonate salts are preferred because they have low water solubility and are soluble in organic solvents. In the present invention, two or more different diazonium salt compounds may be mixed and used at an arbitrary ratio.

In the heat-sensitive recording layer using microcapsules containing a diazonium salt compound, a known heat sensitizer such as an arylsulfonamide compound may be added. Specific examples thereof include toluene sulfonamide and ethylbenzene sulfonamide. Further, in the present invention, two or more different thermal sensitizers may be mixed and used.

The coupler, which reacts with the diazonium salt compound to form a dye, is used in the form of fine particles by emulsion dispersion and / or solid dispersion. Specific examples of the coupler include resorcin, flurglucin, 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-naphthoic acid-N-dodecyloxypurupyramide, 2-hydroxy-3-naphthoic acid tetradecylamide, acetanilide, acetoacetanilide, benzoylacetanilide, 2-chloro-5-octylacetoacetanilide, 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
-Dodecyloxyphenyl) -2-methylcarbonate cyclohexane-3,5-dione, 1- (2-dodecyloxyphenyl) cyclohexane-3,5-dione, N
Mention may be made of -phenyl-N-dodecyl barbituric acid and N-phenyl-N- (3-stearyloxy) butyl barbituric acid. Two or more of these couplers may be used in combination to obtain a desired color hue.

Further, in order to accelerate the dye-forming reaction, it is common to add a base compound which is emulsified and / or solid-dispersed into fine particles. The basic substance includes not only an inorganic or organic basic compound, but also a compound that releases an alkaline substance by decomposition or the like when heated. Representative examples include organic ammonium salts, organic amines, amides, urea and thiourea and their derivatives, thiazoles, pyrroles, pyrimidines, piperazines, guanidines, indoles, imidazoles, imidazolines, triazoles. , Morpholines,
Examples thereof include nitrogen-containing compounds such as piperidines, amidines, formazines and pyridines. Specific examples of these 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, Two
3-tricyclohexylguanidine, guanidine trichloroacetate, N, N'-dibenzylpiperazine, 4,
Mention may be made of 4'-dithiomorpholine, morpholinium trichloroacetate, 2-aminobenzothiazole and 2-benzoylhydrazinobenzothiazole.
These may be used in combination of two or more.

The thermoresponsive microcapsules of the present invention can be produced, 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, alkylnaphthalene, alkyldiphenylethane,
Phosphoric acid derivatives such as alkyl diphenyl methane, diphenyl ethane alkyl adduct, alkyl biphenyl, chlorinated paraffin, tricresyl phosphate, maleic acid esters such as maleic acid-di-2-ethylhexyl, and adipic acid esters. be able to. 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 together. The low boiling point organic solvent used in combination is preferably an organic solvent having a boiling point of 40 to 100 ° C., and specific examples thereof include ethyl acetate, butyl acetate, methylene chloride, tetrahydrofuran and acetone. Moreover, you may use these in mixture of 2 or more types. When only a solvent having a low boiling point (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 are present Easy to be formed.

Depending on the type of the diazonium salt, it may move to the aqueous phase side during the microencapsulation reaction, and in order to suppress this, the acid anion may be appropriately added in advance to the water-soluble polymer solution. Examples of the acid anion include PF ₆ ⁻ , B (−Ph) ₄ ⁻ [Ph is a phenyl group], Z
Examples thereof include nCl 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).

In the present invention, during microencapsulation,
Water is generally used as the compound having active hydrogen that reacts with the (polyvalent) isocyanate prepolymer for forming the microcapsule wall, but water is highly soluble in the organic solvent as the core or as the dispersion medium. It can be added to the molecular solution and used as the above-mentioned compound having active hydrogen (one of the raw materials for the microcapsule wall). Specific examples include propylene glycol, glycerin and trimethylolpropane. Further, an amine compound such as diethylenetriamine or tetraethylenepentamine may be used instead of or in combination with the polyol. These compounds are also described in the above "Polyurethane Resin Handbook".

Examples of the water-soluble polymer 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 / anhydrous. Maleic acid copolymer, ethylene / maleic anhydride copolymer, isobutylene / maleic anhydride copolymer, polyvinylpyrrolidone, ethylene / acrylic acid copolymer, vinyl acetate / acrylic acid copolymer, carboxymethylcellulose, methylcellulose, casein , Gelatin, starch derivatives, gum arabic and sodium alginate. These water-soluble polymers are preferably those that do not react with the isocyanate compound or are extremely difficult to react with them. For example, those that have a reactive amino group in the molecular chain, such as gelatin, must have no reactivity in advance. is necessary.

In the present invention, the surfactant may be used by adding it to either the oil phase or the water phase, but it is easier to add it to the water phase because of its low solubility in organic solvents.
The amount of addition is 0.1 to 5% by weight, especially 0.1
5 to 2% by weight is preferable. Generally, surfactants used for emulsion dispersion are said to be excellent in surfactants having a relatively long-chain hydrophobic group, "Handbook of Surfactants" (Nishiichiro et al.,
Sangyo Tosho Co., Ltd. (1980)), and alkali metal salts of alkylsulfonic acid, alkylbenzenesulfonic acid and the like can be used.

In the present invention, a surfactant (emulsification aid)
It is also possible to use a compound such as a formalin condensate of an aromatic sulfonate or a formalin condensate of an aromatic carboxylic acid. Specifically, the following general formula:

[0058]

Embedded image

[R is an alkyl group having 1 to 4 carbon atoms,
X represents SO ₃ ⁻ or COO ⁻ , M represents a sodium atom or a potassium atom, and p represents an integer of 1 to 20]. The above compound is described in Japanese Patent Application No. 5-83721.

A compound of an alkyl glucoside compound can be used as well. Specifically, the following general formula:

[0061]

[Chemical 9]

A compound represented by [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 in combination of two or more kinds.

A mixed solution (oil phase) of the solution containing the above-mentioned diazonium salt compound (or electron-donating dye precursor), a high boiling point solvent and the like and the polyfunctional isocyanate compound (adduct) of the present invention is mixed with a surfactant and a surfactant. It is added to an aqueous solution (aqueous phase) composed of a water-soluble polymer. At that time, the aqueous solution is added while being stirred by a high shear stirring device such as a homogenizer to emulsify and disperse. After the emulsification, the polymerization reaction catalyst of the isocyanate compound is added or the temperature of the emulsion is raised to carry out the capsule wall forming reaction.

In order to make the prepared microcapsule liquid containing the diazonium salt more practical, it is preferable to intentionally inactivate the diazonium salt leaked outside the capsule to perform the treatment for losing the dye formation. Examples of this reaction quencher include hydroquinone, sodium bisulfite, potassium nitrite, hypophosphorous acid, stannous chloride and formalin. These compounds are described in JP-A-60-214992. Further, as another means to obtain the same effect, a method such as filtration, ion exchange treatment, electrophoresis treatment, chromatography treatment, gel filtration treatment, reverse osmosis treatment, ultrafiltration treatment, dialysis treatment, activated carbon treatment is used. be able to. Among these, ion exchange treatment, reverse osmosis treatment, ultrafiltration treatment and dialysis treatment are preferable. For these methods, see JP-A-61
No. 219688.

In the present invention, an electron-accepting compound, a heat sensitizer, a coupler and a basic compound can be added to the heat-sensitive color forming layer. These are appropriately mixed, separately emulsified and dispersed, or solid dispersed, atomized and added, or appropriately mixed and then emulsified or solid dispersed,
It can be atomized and added. As a method of emulsifying and dispersing, these compounds are dissolved in an organic solvent, and a water-soluble polymer aqueous solution is added with stirring with a homogenizer or the like. In promoting the formation of fine particles, it is preferable to use the above-mentioned hydrophobic organic solvent, surfactant and water-soluble polymer.

To solid-disperse the coupler, the basic substance, the electron-accepting compound, the thermal sensitizer and the like, these powders are put into an aqueous solution of a water-soluble polymer and fine particles are formed by a known dispersing means such as a ball mill. And can be used.
It is preferable to make the particles fine so as to obtain a particle diameter that can satisfy the properties required for the multicolor thermosensitive recording material and the manufacturing method thereof, such as thermal sensitivity, storability, transparency of the recording layer, and suitability for manufacturing.

The microcapsule solution and the preparation solution of the heat sensitizer, the electron-accepting compound, the coupler and the basic compound are mixed in an appropriate ratio and coated on a support. Generally, with respect to 1 mol of the diazonium salt compound,
1 to 10 moles, preferably 2 to 6 moles, of couplers are suitable. The optimum addition amount of the basic compound varies depending on the strength of the basicity, but is generally 0.5 to 5 mol of the diazonium salt compound. The electron-accepting compound (developing agent) is generally added within the range of 0.5 to 30 mol per 1 mol of the electron-donating dye precursor, but preferably within the range of 1 to 20 mol. More preferably, it is added within the range of 3 to 15 mol. The thermal sensitizer is generally added within the range of 0.1 to 20 mol, preferably 0.5 to 10 mol, with respect to the electron-donating dye precursor.

As the support to which these coating solutions are applied, known materials for heat-sensitive recording materials can be used. Examples thereof include paper, coated paper obtained by applying clay or the like on paper, laminated paper obtained by laminating polyethylene, polyester, etc. on paper, synthetic paper, polyethylene terephthalate, polyimide, plastic film such as triacetyl cellulose. Further, it is also possible to use a support in which these synthetic papers and papers or different synthetic papers are bonded together. Examples of the transparent support include the above-mentioned polyethylene terephthalate, triacetyl cellulose, and plastic films of polystyrene, polypropylene, polyethylene and the like.

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

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

Then, the second heat-sensitive layer (second layer) containing a diazonium compound having a higher energy than the previous time and having a light absorption wavelength band different from the light of the absorption wavelength band of the diazonium compound contained in the first layer (first layer). (2) The thermosensitive recording layer (usually a magenta color-developing 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 diazonium compound, thereby remaining in the second heating layer. The diazonium compound is photolyzed. Finally, with higher energy, the innermost layer (third heat-sensitive recording layer, usually cyan coloring layer), the layer containing the electron-donating dye precursor (third layer) is colored to complete the 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 becomes vivid. 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 above three layers to the back surface 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.

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

In the multicolor heat-sensitive recording material, the third heat-sensitive recording layer may be made of an appropriate combination of a diazonium salt compound and a coupler compound.

Examples will be shown below, but the present invention is not limited thereto. In addition, "part" in an Example shows all weight parts.

[0076]

【Example】

[Synthesis Example 1] Synthesis of R ¹¹ = phenyl alcohol compound (a) represented by the general formula (2) 4,4 ′-[1- [4- [1- (4-hydroxyphenyl)- 1-methylethyl] phenyl] ethylidene] bisphenol (TrisP-PA; Honshu Chemical Industry Co., Ltd.)
21.2 g (0.05 mol), glycidyl phenyl ether (Wako Pure Chemical Industries, Ltd.) 30.04 g (0.
20 mol) and 1.29 g (0.0 of tetraethylammonium iodine (manufactured by Wako Pure Chemical Industries, Ltd.) which is a reaction catalyst.
(05 mol) was heated at 120-130 ° C. for 6 hours with stirring. The obtained reaction product was subjected to column fractionation (silica gel / chloroform) to obtain 26.3 g (0.03 mol) of a colorless and transparent viscous alcohol compound (a) in a yield of 60%. ¹ H-NMR (DM
SO-d ₆₎ spectral data were as follows. δppm = 1.60 (6H, s), 2.01 (3H,
s), 4.03 (12H, m), 4.13 (3H,
m), 5.33 (3H, t), 6.84 (6H, d),
6.93 (16H, d), 7.10 (3H, t), 7.
27 (6H, t)

[Synthesis Example 2] Synthesis of alcohol compound (b) of Ar = 2-biphenyl represented by the general formula (2) In Synthesis Example 1, glycidyl (2-biphenyl) ether was used instead of glycidyl phenyl ether. The same procedure as in Synthesis Example 1 was carried out except that the amount was used in a molar amount to obtain 27.6 g (0.025 mol) of a colorless and transparent viscous alcohol compound (b) in a yield of 50%. ¹ H of the above alcohol compound (b)
-NMR (DMSO-d ₆₎ spectral data were as follows. δppm = 1.61 (6H, s), 2.04 (3H,
s), 3.91 (3H, m), 3.98 (3H, m),
4.07 (9H, s), 5.30 (3H, t), 6.7
5 to 7.46 (43H, m)

Synthesis Example 3 Synthesis of isocyanate prepolymer (P-1) Alcohol compound (a) 71.32 obtained in Synthesis Example 1
g (0.0815 mol), 1,3-xylylene diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) 61.38 g (0.
326 mol) and di (2-ethylhexanoic acid) tin (Stannoct; manufactured by Yoshitomi Pharmaceutical Co., Ltd.) which is a urethanization reaction catalyst.
0.133 g was added into 132.7 g of ethyl acetate,
After stirring at 50 ° C. for 6 hours, an isocyanate prepolymer (a terminal isocyanate group-containing polyurethane compound (P-
A 50 wt% ethyl acetate solution of 1)) was obtained. Measurement of molecular weight of the obtained isocyanate prepolymer with a methanol by GPC (column: Showa Denko KK)
Shodex-GPC-KF-802 manufactured by, eluent: tetrahydrofuran (0.8 ml / min), detection: UV
(254 nm)), the molecular weight (MW) was 2
It was 590 (polystyrene conversion). As a result of ¹ H-NMR (DMSO-d ₆ ) measurement of the above isocyanate prepolymer, alcoholic O attributed to 5.33 ppm
No H peak was observed.

[Synthesis Example 4] Synthesis of isocyanate prepolymer (P-2) The same procedure as in Synthesis Example 3 was carried out except that the alcohol compound (b) obtained in Synthesis Example 2 was used as the alcohol compound in Synthesis Example 3. , Isocyanate prepolymer (P-
A 50 wt% ethyl acetate solution of 2) was obtained. The molecular weight (MW) of the methanol adduct of the obtained isocyanate prepolymer (P-2) was 2710, and ¹ H-NMR (D
As a result of MSO-d ₆ ) measurement, no peak of alcoholic OH attributed to 5.30 ppm was observed.

[Evaluation of Physical Properties of Polyurethane-Urea Crosslinked Polymer Membrane Obtained from Isocyanate Prepolymer] The isocyanate prepolymers of P-1 and P-2 obtained in the above Synthesis Examples 3 and 4 and Takenate D as a comparative sample.
A film of -110N (trimethylolpropane / xylylene diisocyanate adduct; manufactured by Takeda Pharmaceutical Co., Ltd.) was formed on a glass substrate and immersed in water at 60 ° C for 4 hours to form a polyurethane-urea crosslinked film. I of the film obtained here
When the R spectrum was measured, residual isocyanate groups were not confirmed. [Measurement of Water Content of Obtained Polyurethane-Urea Crosslinked Polymer Membrane] The polyurethane-urea crosslinked polymer membrane obtained above was freeze-pulverized with liquid nitrogen, and then in a constant temperature and high humidity chamber at 25 ° C. and 80% RH. The moisture content was measured with a Karl Fischer moisture meter (trace moisture analyzer AQ-7, manufactured by Hiranuma Sangyo Co., Ltd.) after time humidity control. Table 1 shows the measurement results of the water content.

[0082]

[Table 1] Table 1 ──────────────────────────── Sample moisture content (%) ─────────── ────────────────── [Polyurethane / Urea of the Present Invention] When P-1 of Synthesis Example 3 is used 1.3 P-2 of Synthesis Example 4 is used Case 0.96 ──────────────────────────── Conventional example: When Takenate D-110N is used 2.5 ──── ────────────────────────

[Example 1] (I) Preparation of coating liquid for thermosensitive recording layer (B) (1) Preparation of capsule emulsion of diazonium salt compound ("parts" below mean "parts by weight") As a diazonium salt compound, 2.8 parts of the compound shown in the following (B-1) having a maximum absorption wavelength of decomposition at 365 nm was converted into ethyl acetate 1
Dissolved in 0.0 parts. Furthermore, 2.1 parts of isopropyl biphenyl, which is a high boiling point solvent, was added and heated to be mixed uniformly.

[0084]

[Chemical 10]

As a capsule wall agent, (P
11.4 parts of the polyvalent isocyanate prepolymer of -1) was further added to the above mixed solution and stirred uniformly. Separately 1
6% by weight gelatin added with 2.0 parts of 0% by weight sodium dodecylsulfonate aqueous solution (trade name: MGP-906
6, 64 parts of an aqueous solution of Nippi Gelatin Industry Co., Ltd. was prepared, the mixed solution of the above diazonium salt compound was added, and the mixture was emulsified and dispersed by a homogenizer.

(2) Encapsulation reaction After 20 parts of water was added to the obtained emulsion to homogenize it, the mixture was reacted for 30 minutes at 40 ° C. with stirring, then heated to 50 ° C. and encapsulation reaction for 3 hours. Was done. After that, the liquid temperature was lowered to 35 ° C. and the ion exchange resin Amberlite IRA6 was used.
8 (manufactured by Organo) 6.5 parts, Amberlite IRC5
13 parts of 0 (manufactured by Organo) were added, and the mixture was further stirred for 1 hour. After that, the ion exchange resin was filtered to obtain a target capsule liquid. The average particle size of the capsule was 1.5 μm.

(3) Preparation of Emulsion Dispersion of Coupler As a coupler, compound (B-2) 3.0 shown below was used.
Part, triphenylguanidine 8.0 parts, 1,1- (p-
Hydroxyphenyl) -2-ethylhexane was 8.0
Part, 4,4 '-(p-phenylenediisopropylidene)
8.0 parts of diphenol, compound (B-3) shown below
2.0 parts, and 1,1,3-tris (2-methyl-4-)
2.0 parts of hydroxy-5-t-butylphenyl) butane are dissolved in 10.5 parts of ethyl acetate, and 0.48 parts of tricresyl phosphate as a high-boiling solvent, 0.24 parts of diethyl maleate and Pionine A41C ( Takemoto Yushi Co., Ltd.
(Manufactured by Mitsui Chemicals Co., Ltd.) and then heated and mixed uniformly.
This mixture was mixed with 8 wt% gelatin (# 750 gelatin,
This was added to 93 parts of Nitta Gelatin Co., Ltd. aqueous solution and emulsified and dispersed by a homogenizer. The remaining ethyl acetate was evaporated from this emulsion to obtain the target emulsion dispersion.

[0088]

[Chemical 11]

[0089]

[Chemical 12]

(4) Preparation of coating liquid The above-mentioned diazonium salt compound capsule liquid, coupler emulsion dispersion, and styrene / butadiene rubber (SBR-SN).
307, Sumitomo Nogatta Co., Ltd., and the ratio of the diazonium salt compound / coupler is 1/2 and the ratio of the diazonium salt compound / styrene-butadiene rubber is 1 respectively.
The mixture was mixed at a ratio of /6.4 to prepare a target coating solution for the heat-sensitive recording layer (B).

(II) Preparation of coating solution for heat-sensitive protective layer (D): To 61 parts of 5.0 wt% itaconic acid-modified polyvinyl alcohol (KL-318, Kuraray Co., Ltd.) aqueous solution, 2 parts were added.
0.5 wt% zinc stearate dispersion (Hydrin F
115, manufactured by Chukyo Yushi Co., Ltd.) (2.0 parts by weight) was added, and 8.4 parts of a 2% by weight aqueous solution of the compound (D-1) shown below,
Fluorine-based release agent (ME-313, manufactured by Daikin) 8.0
Part, wheat flour starch (KF-4, Kagoshima Starch Co., Ltd.) 0.5
Parts were added and stirred uniformly. This is called mother liquor.

[0092]

[Chemical 13]

Separately, 12.5 parts of ion-exchanged 20% by weight aqueous solution of chaogroth (manufactured by Shiraishi Industry Co., Ltd.), Poise 5
32A (manufactured by Kao Corporation) 0.06 part, Hydrin Z-7
(Manufactured by Chukyo Yushi Co., Ltd.) 1.87 parts, 10 wt% polyvinyl alcohol (PVA105, Kuraray Co., Ltd.) aqueous solution 1.25 parts, 2 wt% sodium dodecyl sulfonate aqueous solution 0.39 parts are mixed, Finely dispersed with a dyno mill. This liquid is called a pigment liquid. To 80 parts of the above mother liquor, 4.4 parts of the pigment liquid was added and stirred for 30 minutes or more. Then We
Add 2.8 parts of tmaster500 (manufactured by Toho Chemical Co., Ltd.), and add 3 more
The mixture was stirred for 0 minutes or more to obtain a desired coating solution for the heat-sensitive protective layer (D).

(III) Coating The heat-sensitive recording layer (B) was coated with a wire bar on a printing paper support obtained by laminating polyethylene on high-quality paper.
And the coating liquid for the protective layer (D) were sequentially coated and dried to obtain a heat-sensitive recording material. The coating amount as a solid content was 8 g and 1 g per 1 m ^2, respectively.

[Example 2] In Example 1, (1) in the preparation of a capsule emulsion of a diazonium salt compound, instead of the isocyanate prepolymer (P-1), the isocyanate prepolymer (P-2) of Synthesis Example 4 was used. A thermal recording material was prepared in the same manner as in Example 1 except that was used.

Example 3 In Example 1, (1) in the preparation of a capsule emulsion of a diazonium salt compound, 11.4 parts of the polyvalent isocyanate prepolymer of (P-1) in Synthesis Example 3 was used. 9.0 parts of the polyvalent isocyanate prepolymer of (P-1) in Synthesis Example 3 above, 1.2 parts of xylylene diisocyanate / trimethylolpropane adduct (Takenate D110N, 75% by weight ethyl acetate solution) and Japanese Patent Application Xylylene diisocyanate / bisphenol A synthesized according to the method described in JP-A-5-233536.
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that a mixture of 1.2 parts of a 30 wt% ethyl acetate solution of the adduct was used.

[Comparative Example 1] In Example 1, (1) in the preparation of a capsule emulsion of a diazonium salt compound, xylylenediisocyanate / trimethylolpropane adduct (takenate) was used instead of the isocyanate prepolymer (P-1). D110N, 75 wt% ethyl acetate solution) 7.
A thermal recording material was prepared in the same manner as in Example 1 except that 6 parts were used. The average particle size of the capsule was 1.0 μm.

(IV) Thermal Recording Using a thermal head KST type (manufactured by Kyocera Corp.), the thermal recording characteristics of the above thermal recording materials were evaluated as follows. (1) Recording energy per unit area is 30-50mJ
The electric power applied to the thermal head and the pulse width were set so as to be / mm ^2, and printing was performed on the thermosensitive recording material to record a magenta image. (2) Use the recording material with an emission center wavelength of 365 nm and an output of 4
It was irradiated with a 0 W ultraviolet lamp for 15 seconds to fix the image on the unprinted portion. As for the color density of the magenta image, the Macbeth densitometer (RD918 type) was used to measure the optical reflection density of the color portion. The recording energy at which the magenta density was 0.5 was defined as the sensitivity. (3) Evaluation of humidity dependency of sensitivity The measurement of the above (1) to (2) was performed at a temperature of 25 ° C. and a humidity of 10%.
The sensitivity was determined for each magenta by conducting RH, temperature 25 ° C., and humidity 80% RH. The above results are shown in Table 2.

[0099]

[Table 2] Table 2 ────────────────────────── Humidity dependence of color density sensitivity (mJ / mm ² ) (40 mJ / mm ² ) (10% RH) (80% RH) ────────────────────────── Example 1 0.8 40 30 Example 2 0. 8 39 30 Example 3 0.8 43 31 ────────────────────────── Comparative Example 1 0.65 52 36 36 ───── ─────────────────────

[Example 4] (Preparation of coating liquid for thermosensitive recording layer (A)) (1) Preparation of capsule liquid of diazonium salt compound The following compound (A having a maximum absorption wavelength of decomposition at 420 nm as a diazonium salt compound) -1) 3.5 parts and compound (A-2) 0.9 parts are melt | dissolved in ethyl acetate 16.4 parts, isopropyl biphenyl which is a high boiling point solvent 9.8 parts is further added, and it heats and it becomes uniform. Mixed.

[0101]

Embedded image

[Chemical 15]

4.5 parts of xylylene diisocyanate / trimethylol propane adduct (Takenate D110N, 75% by weight ethyl acetate solution) as a capsule wall agent were prepared by the method described in Japanese Patent Application No. 5-233536. Then, 9 parts of a mixture of 4.5 parts of a 30 wt% ethyl acetate solution of the xylylene diisocyanate / bisphenol A adduct was added and stirred uniformly. Separately
77 parts of 6% by weight gelatin aqueous solution to which 0.36 part of ScraphAG-8 (manufactured by Nippon Seika Co., Ltd.) was prepared, and the mixed solution (solution) of the diazonium salt compound was added and emulsified and dispersed by a homogenizer. did. After 20 parts of water was added to the obtained emulsion to homogenize it, an encapsulation reaction was carried out for 3 hours while stirring at 40 ° C. Thereafter, the liquid temperature was lowered to 35 ° C., 6.5 parts of an ion exchange resin Amberlite IRA68 (manufactured by Organo Co.) and 13 parts of Amberlite IRC50 (manufactured by Organo Co.) were added, and the mixture was further stirred for 1 hour. After that, the ion exchange resin was filtered, and then 0.4 parts of a 1 wt% hydroquinone aqueous solution was added to 10 parts of the capsule liquid, followed by stirring. In this way, a capsule liquid of the diazonium salt compound was obtained. The average particle size of the capsule is 0.91μ
It was m.

(2) Preparation of Coupler Dispersion Liquid 2.4 parts of the following compound (A-3) and 4.1 parts of triphenylguanidine as a coupler, 1,1- (p-hydroxyphenyl) -2-ethylhexane 4 1st part, 4, 4 '
3.6 parts of-(p-phenylenediisopropylidene) diphenol and 0.8 parts of the following compound (A-4) were dissolved in 8.0 parts of ethyl acetate, and pionein A41C (manufactured by Takemoto Yushi Co., Ltd.). After adding 1.0 part, it heated and mixed uniformly.

[0104]

Embedded image

[Chemical 17]

The above mixture was mixed with gelatin (#
750 gelatin, manufactured by Nitta Gelatin Co., Ltd., was added to 75.0 parts of a 10% by weight aqueous solution and emulsified and dispersed by a homogenizer. The remaining ethyl acetate was evaporated from this emulsion to obtain the target emulsion dispersion.

(3) Preparation of coating liquid The above-mentioned diazonium salt compound capsule liquid, coupler emulsion dispersion, styrene-butadiene rubber (trade name SBR-S)
N307, manufactured by Sumitomo Nogatac Co., Ltd., was mixed so that the ratio of the diazonium salt compound to the coupler was 1 / 3.2, and the weight of the styrene / butadiene rubber was equal to the weight of gelatin of the coating solution. Was prepared.

(Preparation of Coating Liquid for Thermal Recording Layer (C)) (4) Preparation of Electron Donor Dye Precursor Capsule Emulsion Liquid 3- (o-methyl-p-diethylaminophenyl) -as electron donor dye precursor 0.39 parts of 3- (1'-ethyl-2-methylindol-3-yl) phthalide, 0.19 parts of 2-hydroxy-4-methoxybenzophenone having a maximum absorption wavelength at 285 nm as an ultraviolet absorber, and an antioxidant As a result, 0.25-part of 2,5-tert-octylhydroquinone was dissolved in 0.93 part of ethyl acetate,
Further, 0.54 parts of phenethylcumene, which is a high boiling point solvent, was added and heated to uniformly mix. As a capsule wall agent, 1.0 part of xylylene diisocyanate / trimethylolpropane adduct (Takenate D110N) was further added to this solution and stirred uniformly. Separately, 36.4 parts of a 6% by weight gelatin (MGP-9066, manufactured by Nippi Gelatin Industry Co., Ltd.) aqueous solution to which 0.07 part of a 10% sodium dodecylsulfonate aqueous solution was added was prepared, and the electron-donating dye precursor was prepared. The body solution was added and emulsified and dispersed by a homogenizer. The emulsion dispersion thus obtained is called a 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 and 2,
4.4 parts of 5-tert-octylhydroquinone was dissolved in 14.4 parts of ethyl acetate, 8.4 parts of phenethylcumene as a high boiling point solvent was further added, and the solution was stirred uniformly and the takenate previously used was added. 7.8 parts D110N and methylene diisocyanate (Millionate MR200,
5.9 parts of Nippon Polyurethane Co., Ltd. was added and stirred uniformly. The solution thus obtained and 1.2 parts of a 10% sodium dodecyl sulfonate aqueous solution were added to the above primary emulsified dispersion, and the mixture was emulsified and dispersed by a homogenizer.
The liquid thus obtained is called a secondary emulsion dispersion. 60.0 parts of water and 0.4 parts of diethylenetriamine were added to this secondary emulsified dispersion liquid to homogenize the mixture, and then the mixture was mixed with stirring 6
The temperature was raised to 5 ° C. and the encapsulation reaction was carried out for 3.5 hours to obtain a target capsule emulsion. The average particle size of the capsule is 1.
It was 9 μm.

(5) Preparation of Electron-Accepting Compound Dispersion Liquid 30 parts of bisphenol P as an electron-accepting compound was gelatin (MGP-9066, Nippi Gelatin Industry Co., Ltd.).
Manufactured by K.K.) to 82.5 parts of a 2.0% by weight aqueous solution, and further 7.5 parts of a 2% by weight aqueous solution of sodium 2-ethylhexylsulfosuccinate, and the resulting mixture is dispersed and dispersed in a ball mill for 24 hours. A liquid was prepared. To this dispersion was added 36.0 parts of a 15 wt% gelatin (# 750 gelatin, manufactured by Nitta Gelatin Co., Ltd.) aqueous solution, and the mixture was stirred uniformly to obtain an electron-accepting compound dispersion. The average particle size of the electron-accepting compound in the dispersion was 0.5 μm.

(6) Preparation of coating liquid Next, the above-mentioned electron-donating dye precursor capsule liquid, electron-accepting compound dispersion liquid, 15% by weight gelatin (# 750 gelatin, Nitta Gelatin Co., Ltd.) aqueous solution and Stilbene-based optical brightener (Whitex-BB, manufactured by Sumitomo Chemical Co., Ltd.)
The ratio of electron-donating dye precursor / electron-accepting compound is 1/14, electron-donating dye precursor / # 750 gelatin =
1.1 / 1, and electron donor dye precursor / fluorescent whitening agent = 5.3 / 1 were mixed to prepare a target coating solution.

(7) Preparation of the intermediate layer (E) solution: 8.2 parts of a 4% by weight boric acid aqueous solution in a 14% by weight aqueous solution of gelatin (# 750 gelatin, manufactured by Nitta Gelatin Co., Ltd.),
1.2 parts of a 2 wt% aqueous solution of sodium (4-nonylphenoxytrioxyethylene) butyl sulfonate and 7.5 parts of a 2 wt% aqueous solution of the following compound (E-1) were added,
The desired coating liquid was prepared by uniformly stirring.

[0111]

Embedded image

(8) Coating On the surface of a printing paper support in which polyethylene is laminated on a high-quality paper, a thermosensitive recording layer (C),
The intermediate layer (E), the heat-sensitive recording layer (B) described in Example 1, the intermediate layer (E), the heat-sensitive recording layer (A) and the protective layer (D) are applied and dried in this order to obtain the desired multicolor heat-sensitive property. A recording material was obtained.
The coating amount as solid content is 7 g, 3 g, and 8 per 1 m ² respectively.
It was g, 3 g, 6 g, and 1 g.

Example 5 The procedure of Example 4 was repeated except that the diazonium salt compound capsule liquid (2) described in Example 2 was used as the capsule liquid of the diazonium salt compound used in the thermosensitive color developing layer (B). A multicolor thermosensitive recording material was obtained in the same manner as in Example 4.

(9) Thermal recording Using a thermal head KST type (manufactured by Kyocera Corp.), the thermal recording characteristics of the above thermal recording materials were evaluated as follows. (1) The applied power to the thermal head and the pulse width were adjusted so that the recording energy per unit area was 35 mJ / mm ^2, and printing was performed on the thermal recording material to record a yellow image. (2) Use the recording material with an emission center wavelength of 420 nm and an output of 4
Irradiate with a 0 W ultraviolet lamp for 10 seconds. (3) Determine the applied power and pulse width to the thermal head so that the recording energy per unit area becomes 70 to 90 mJ / mm ² again, print and print the magenta image. Recorded. Furthermore, (4) irradiate for 15 seconds with an ultraviolet lamp having an emission center wavelength of 365 nm and an output of 40 W, and (5) adjust the applied power and pulse width to the thermal head so that the recording energy per unit area becomes 140 mJ / mm ^2. , And a cyan image was recorded. As a result, in addition to the yellow, magenta, and cyan color-developed images, the recording area where the yellow and magenta recording overlap is red, the area where the magenta and cyan overlap is blue, and the area where the yellow and cyan overlap is green. , And the image portion where the yellow, magenta, and cyan recordings were overlapped developed a black color. The unrecorded area is
It was off-white. The optical reflection densities of the yellow, magenta, and cyan color-developed portions were measured with a Macbeth RD918 densitometer. The recording energy at which the magenta density was 0.5 in the above (3) was taken as the sensitivity. (6) Evaluation of humidity dependency of sensitivity The measurement of the above (1) to (5) was performed at a temperature of 25 ° C. and a humidity of 10%.
The sensitivity was determined for each magenta by conducting RH, temperature 25 ° C., and humidity 80% RH. The results are shown in Table 3.

[0115]

[Table 3] Table 3 ──────────────────────────────── Color density Density sensitivity (mJ / mm ² ) dependence on humidity Properties Yellow Magenta Cyan Magenta (80mJ / mm ² ) (10% RH) (80% RH) ────────────────────────────── ─── Example 4 0.80 1.00 1.20 65 55 Example 5 0.80 0.95 1.20 64 55 ──────────────────── ─────────────

[0116]

The thermoresponsive microcapsules of the present invention are
Since the water content of the capsule wall is low, the sensitivity to heat is high and the humidity dependency of the sensitivity is low, and it has excellent characteristics that it shows almost the same high sensitivity under any humidity condition. Therefore, when the above-mentioned microcapsules are used in the heat-sensitive recording layer of the heat-sensitive recording material, the humidity dependence of the sensitivity is low, and a recording material exhibiting substantially the same high sensitivity and color forming property under any humidity condition is obtained. You can further,
When the above-mentioned microcapsules are used for a heat-sensitive recording layer (especially effective for a cyan color-developing layer that requires high sensitivity), a multicolor heat-sensitive recording material having high sensitivity and low humidity dependency of sensitivity can be obtained. it can.

Claims (6)

[Claims] 1. The following general formula (1): (However, R ¹ , R ² and R ³ each independently represent an aryl group, a heterocyclic group or an alkyl group, and R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or an alkyl group, and R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkoxy group or an aryl group.). 2. R ¹ , R ² and R ³ are each independently an aryl group having 6 to 16 carbon atoms or 4 to 1 carbon atoms.
6 represents an alkyl group, R ⁴ , R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 4 carbon atoms,
R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, or 1 to 1 carbon atoms.
The alcohol compound according to claim 1, which represents an alkoxy group having 6 or an aryl group having 6 to 14 carbon atoms. 3. An isocyanate prepolymer obtained by adding a bifunctional isocyanate having two isocyanate groups in the molecule to the alcohol compound represented by the general formula (1) according to claim 1. 4. A microcapsule encapsulating a diazo compound or an electron-donating dye precursor, wherein the capsule wall of the microcapsule contains the isocyanate prepolymer according to claim 3 and two or more active hydrogens in the molecule. A thermoresponsive microcapsule comprising a polymer obtained by polymerizing the compound with the compound. 5. A heat-sensitive recording comprising a support and a microcapsule and a coupler encapsulating the diazo compound provided thereon, or a microcapsule containing an electron-donating dye precursor and a thermosensitive recording layer containing a color developer. A heat-sensitive recording material, characterized in that the microcapsules are the thermoresponsive microcapsules according to claim 4. 6. A transparent support and a cyan, magenta, and yellow thermosensitive recording layer provided thereon, each recording layer containing a microcapsule and a coupler containing a diazo compound, or an electron-donating dye precursor. A multicolor heat-sensitive recording material comprising a microcapsule encapsulating and a color developer, wherein the microcapsule is the thermoresponsive microcapsule according to claim 4.