JPH07164756A - Thermal recording material - Google Patents

Abstract

PURPOSE:To enhance the stability of a ground color and reversible recording properties, in the thermal recording material having a thermal color forming layer containing a dye precursor and a coupler, by using a specific urea compd. as the coupler to add the same to the thermal color forming layer. CONSTITUTION:A thermal recording material having a thermal color forming layer containing a colorless or light-colored dye precursor and a coupler reacting with the dye precursor at the time of heating to develop a color develops a color by instantaneous chemical reaction generated by heating due to a thermal head, a hot stamp or laser beam to obtain visible recording. In this case, a urea compd. represented by either one of formulae I, II (wherein X is a 1-18C alkyl group or a 3-10C cycloalkyl group, Y is a 1-12C alkyl group or a halogen atom, A is a divalent group having 30 or less carbon atoms and B is a trivalent group having 30 or less carbon atoms) is used as the coupler to be added to the thermal color forming layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material having excellent ground color stability and a heat-sensitive recording material having vivid color tone and reversible recording property.

[0002]

2. Description of the Related Art Generally, a heat-sensitive recording material is prepared by grinding and dispersing a colorless or light-colored electron-donating colorless dye and a color developing agent such as a phenolic compound into fine particles, respectively, and then mixing the two. A coating solution obtained by adding a binder, a filler, a sensitivity improver, a lubricant, and other auxiliaries is applied to a support such as paper, synthetic paper, film, plastic, etc., and a thermal head (thermal head). , A hot stamp, laser light, or the like is used to generate a visible record by developing a color by an instantaneous chemical reaction.

The thermosensitive recording medium is applied to a wide range of fields such as a measuring recorder, a computer terminal printer, a facsimile, an automatic ticket vending machine and a bar code label. However, recently, the diversification of recording devices for thermal recording media,
Higher performance is being promoted, and therefore, the quality required for the thermal recording material is also higher. For example, from the viewpoint of speeding up recording, it is possible to obtain a clear color image with high density even with smaller thermal energy. On the other hand, from the viewpoint of storage stability of the recording material, light resistance,
It is required to have excellent oil resistance, water resistance and solvent resistance.

On the other hand, as the method of recording on plain paper such as the electrophotographic method and the ink jet method has become widespread, thermal recording is often compared with the recording on plain paper. For example, it is required that the stability of the recording portion (image) and the stability of the non-recording portion (background color portion) before and after recording (hereinafter referred to as background color stability) approach the quality comparable to plain paper recording. ing. Particularly, as a basic function of heat-sensitive recording, ground color stability against heat and solvent has been required, and so to speak, it has been desired to be heat-sensitive only at the time of recording and insensitive otherwise.

Regarding the background color stability of the thermal recording material, for example,
Japanese Patent Laid-Open No. 4-353490 discloses a heat-sensitive recording material in which the whiteness of the ground color and the recording density do not decrease even under a high temperature condition of about 90 ° C.

On the other hand, the rapid increase in the amount of recording materials consumed with the construction of various networks and the spread of facsimiles and copying machines causes social problems such as dust disposal. As one idea for dealing with this problem, a reversible recording medium capable of repeatedly recording and erasing has been attracting attention.

Regarding the recording medium having reversible recording property, it is detailed in a review article such as the Paper and Paper Cooperative Journal 47 11 (1993) p1309-1322. For example, JP-A-3-230993 and JP-A-4-366682 are available. Discloses a recording material that utilizes the reversible change of a recording material between a transparent state and a cloudy state depending on a given temperature, and a recording material that utilizes the reversibility of a thermochromic material and a reversible dye of a leuco dye. A recording body using various color tone changes has been proposed.

[0008]

The background color stability of the thermosensitive recording medium disclosed in Japanese Patent Laid-Open No. 4-353490 is 95% in a dryer.
When processed at 5 ° C for 5 hours, the Macbeth density of the ground color is about 0.11, which shows considerable stability, but is still insufficient, and it is not possible to heat-laminate the colored surface with a plastic film. It was

Regarding a reversible recording material, a recording material utilizing the reversible change of the recording material between a transparent state and a cloudy state (in other words, a recording material utilizing a change in transparency of the recording material) is (1) Poor image clarity,
(2) There are drawbacks such as slow white turbidity (decoloring) speed and (3) temperature control required for erasing. Also, with this recording medium, in order to create contrast with white turbidity and transparency,
There is no problem in using it as a transparent recording material such as OHP, but when the recording material is coated on a white opaque support like a conventional thermal recording material, it is necessary to provide a colored layer on the back. is there. Therefore, the coating layer (the layer that reversibly changes to a transparent / white turbid state) on the colored layer should have a thin layer in order to obtain contrast, in other words, to clearly show the color of the colored layer (color of the base). On the other hand, on the other hand, in order to appear white, a thick layer is preferable, and strictness of the coating layer is required.

In a reversible recording medium using a thermochromic material, most of the thermochromic material is
There is a problem that the memory property is poor and continuous heat supply is required to maintain the color-developed state.

On the other hand, reversible recording materials using a leuco dye as a color-forming source are disclosed in JP-A-60-193691 and JP-A-60.
Although reversible recording bodies are disclosed in Japanese Patent Publication No. 257289, these recording bodies have a problem in practical use because they are decolorized with water or water vapor. In addition, Japanese Patent Laid-Open No. 2-18
No. 8293, JP-A-2-188294, and the like, a material having a simple layer structure and having a color developing effect and a color reducing effect for reversibly changing the color tone of a leuco dye only by controlling thermal energy (a color reducing agent). ) Is disclosed. However, in this color-developing / reducing agent, the decoloring process has already contributed in the color-developing process, so that there is a problem that the color density is low. Also recently, Ja
In pan Hardcopy '93, Yokota et al. announced a recording medium using an amidophenol derivative having a long-chain alkyl, but this recording medium also requires a temperature control for erasing. There was a flaw.

Therefore, it is an object of the present invention to provide a heat-sensitive recording material having an excellent ground color stability against heat and solvent as a basic function. As an additional function, record-
An object of the present invention is to provide a heat-sensitive recording material having a reversible recording property that can be erased and re-recorded.

[0013]

Means for Solving the Problems The above problems have been solved by a thermosensitive recording medium using a urea-based developer having a structure completely different from that of a general phenol-based developer.

The present invention relates to a thermosensitive recording medium having a thermosensitive color developing layer containing a colorless or pale color dye precursor and a developer which reacts upon heating to develop the color of the dye precursor. The present invention relates to a urea compound represented by the general formula (1) or (2), wherein the thermosensitive coloring layer contains at least one kind of the urea compound.

[Chemical 3]

(Where X is a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms, a substituted or unsubstituted C 3 to C 3
10 cycloalkyl groups, substituted or unsubstituted 7 to 7 carbon atoms
Represents 14 aralkyl groups. Y represents a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a halogen atom, or a hydrogen atom. In addition, A is a divalent group having 30 or less carbon atoms, and B is 3 or less having 3 or less carbon atoms.
Represents a valence group. ) The urea compound represented by the general formula (1) or (2) is a phenylurea type structure (-Ar-NH
It can be considered as a compound having two or three -C (= O) -NH-) in the molecule.

A urea compound represented by the general formula (1) (referred to as a dimerized urea compound in the present invention) and a urea compound represented by the general formula (2) (in the present invention, a trimerized urea compound) Can be synthesized, for example, by reacting an amine with an isocyanate compound.

[Chemical 4]

First, for the dimerized urea compound represented by the general formula (1), (a) a method of reacting a diamine with a monoisocyanate compound or (b) a method of reacting a diisocyanate compound with a monoamine. It is possible to synthesize by using such as.

[Chemical 5]

When a diisocyanate is reacted with a monoisocyanate compound, as the diamine, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, sulfurized 4,4'-diaminodiphenyl, 4,4 'is used. -Diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodicyclohexylmethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diamino- 3,3'-dichlorodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane,
4,4'-diamino-1,2-diphenylethane, 4,4'-diaminodiphenylamine, 2,2'-diaminodiphenyldisulfide, 4,4'-diaminodiphenyldisulfide, 2,2-
Bis (4-aminophenoxyphenyl) propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, α, α'-bis (4-aminophenyl) -1,4-
Examples include diisopropylbenzene, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 2,4-diaminoazobenzene, 4,4'-diaminostilbene, gin, and the like, and a monoisocyanate compound such as methyl isocyanate. , Ethyl isocyanate, n-propyl isocyanate, iso-propyl isocyanate, n-butyl isocyanate, tert-butyl isocyanate, n-octadecyl isocyanate, chloromethyl isocyanate, 2-chloroethyl isocyanate, cyclohexyl isocyanate, Aliphatic isocyanate compounds such as benzyl isocyanate and m-isopropenyl cumyl isocyanate can be mentioned, and any combination can be selected from them.

On the other hand, when the diisocyanate compound is reacted with monoamines, the diisocyanate compound is 4,4'-diphenylmethane diisocyanate (MDI) or the like, and the monoamines are methylamine, ethylamine, n-propylamine, iso-propylamine, n-butylamine, iso-butylamine, sec-butylamine, tert-
Butylamine, n-pentylamine, n-hexylamine,
n-heptylamine, n-octylamine, n-nonanoylamine, n-decylamine, n-stearylamine, 2-ethylhexylamine, 2- (2-aminoethylamino) ethano-
, Cyclohexylamine, 2-aminocyclohexano-
, Benzylamine, o-methylbenzylamine, p-methylbenzylamine, o-chlorobenzylamine, m-chlorobenzylamine, p-chlorobenzylamine, N- (aminomethyl) morpholine, N- (2-aminoethyl ) Aliphatic amines such as morpholine and N- (3-aminopropyl) morpholine are listed, and they can be selected in any combination from both.

On the other hand, the trimerized urea compound represented by the general formula (2) can also be prepared by reacting triamines with a monoisocyanate compound or by reacting a triisocyanate compound with a monoamine. It is possible to synthesize. For example, triphenylmethane triisocyanate, tris (isocyanatophenyl) thiophosphate, or the like can be used as the triisocyanate compound, and can be obtained by reacting with the above-mentioned monoamines.

Specific examples of the urea compound represented by the general formula (1) or (2) include the following compounds.

[0022]

[Chemical 6]

[Chemical 7]

[Chemical 8]

[Chemical 9]

[Chemical 10]

[Chemical 11]

[Chemical 12]

[Chemical 13]

[Chemical 14]

[Chemical 15]

[Chemical 16]

The group connecting the phenylurea structure inside the molecule, which is A in the general formula (1) and B in the general formula (2), depends on the melting point of the urea compound, the decomposition temperature and the solubility in a solvent. It should be appropriately selected and is not particularly limited. However, considering the availability of raw materials, the urea compound represented by the following general formula (3) or (4) is more preferable. In other words, in a thermosensitive recording material having a thermosensitive coloring layer containing a colorless or light-colored dye precursor and a developer which reacts when heated to develop the dye precursor, the developer has the following general formula (3): ) Or (4), the heat-sensitive recording material is characterized in that the heat-sensitive color forming layer contains at least one kind of the urea compound.

[Chemical 17] (Here, X is a substituted or unsubstituted C1-C18 alkyl group, a substituted or unsubstituted C3-C10 cycloalkyl group, or a substituted or unsubstituted C7-C14 aralkyl group. Y represents a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a halogen atom, or a hydrogen atom.
A ₁ is S, O, SO ₂ , CH ₂ , CH ₂ CH ₂ , C
(CH) ₂ , C (= O), NH, NHC (= O) are represented, and B ₁ is CH, PO ₃ . )

In the case of the dimerized urea compound, a urea compound having a phenylurea structure directly linked thereto, that is, a urea compound represented by the general formula (5) is also conceivable, but it is generally used from the viewpoint of safety of raw materials. Seems to require attention.

[Chemical 18] (Here, X is a substituted or unsubstituted C1-C18 alkyl group, a substituted or unsubstituted C3-C10 cycloalkyl group, or a substituted or unsubstituted C7-C14 aralkyl group. Y represents a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a halogen atom, or a hydrogen atom.
In addition, A represents a divalent group having 30 or less carbon atoms. )

As for the substituent of the urea structure at the terminal of the molecule, that is, X in the general formula (1) or (2), like the linking group inside the molecule, the melting point of the urea compound,
It should be appropriately selected depending on the decomposition temperature and the solubility in a solvent, and is not particularly limited. However, from the viewpoint of recording density, the following is more preferable.

(A) X is a substituted or unsubstituted C1-18
In particular, the substituted or unsubstituted alkyl group having 3 to 5 carbon atoms is preferable, and particularly the substituted alkyl group is a halogenated alkyl group or morpholine represented by the general formula (6). Alkyl groups having a residue are preferred.

[Chemical 19] (Here, m represents an integer of 1 to 12.) (b) When X is a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cyclohexyl group is particularly preferable. . (c) when X is a substituted or unsubstituted aralkyl group having 7 to 14 carbon atoms, among them, a substituted or unsubstituted benzyl group,
A substituted or unsubstituted phenylethyl group and the like are preferable.

Patents for using a monourea compound in a heat-sensitive recording material are disclosed in JP-A-58-211496 and JP-A-59-184694.
JP-A No. 61-211085 and the like. These monourea compounds are urea compounds obtained by substituting the amino group portion on one side of urea, and have basically different structures from the dimerized or trimerized phenylurea compound of the present invention. Generally, a heat-sensitive recording material is used by being dispersed in water, but a monourea compound is problematic because it shows some water solubility, and heat resistance (150 ° C.) remains unsatisfactory. Further, a heat-sensitive recording material using a dimerized urea type compound is disclosed in JP-A Nos. 5-1317152 and 5-147357.
It is disclosed in Japanese Patent Publication No. This dimerized urea type compound has a structure having a sulfonyl group adjacent to a urea group (A
_{r-SO 2 -NH- (C =} O) -NH-) are characterized. However, this dimerized urea compound also has a problem in heat resistance (150 ° C.).

However, heat-sensitivity using the dimerized urea compound represented by the general formula (1) or (3) or the trimerized urea compound represented by the general formula (2) or (4) of the present invention. The recording body, as a basic performance,
Excellent ground color stability against heat and solvent. That is, this recording material does not substantially develop color even when placed in a high temperature environment of 120 ° C. or higher. For example, the recording material using Exemplified Compound A-5 does not develop any color even at 150 ° C., which is the maximum temperature for static color development. However, when the high energy of the thermal head, which is usually 200 ° C to 300 ° C, is applied instantaneously, it develops a dark color. Regarding the heat resistance of the background color, in the field of thermal recording media up to now, even though a thermal block of 120 ° C or higher was applied to the surface of the thermal recording layer to produce no color, a thermal head with a density sufficient for practical use was used. Recording is unthinkable, and no material capable of doing so was known.

Since the heat-sensitive recording material of the present invention has such high heat resistance, it is impossible to perform heat-laminating in which the recording surface after heat-sensitive recording is heat-bonded with a plastic film or the like, which has been impossible in the past. To be used as a photographic transfer sheet to attach toner to the surface of the heat-sensitive layer for thermal fixing,
Alternatively, it has become possible to attach a toner to the recording surface of the sheet on which heat-sensitive recording has been carried out and to fix it by heat.

Furthermore, the thermal recording material of the present invention is extremely easy to control the manufacturing process. That is, conventionally, in the production of a thermosensitive recording medium, the drying step after coating the thermosensitive coloring layer requires very strict temperature control so that the background coloring of the coated surface does not occur, and therefore, there is a limit to high-speed coating. there were. However, the thermosensitive recording medium of the present invention does not develop the ground color even when hot air of 120 ° C. is applied in the dried state, so that it can be dried at a high temperature, and the control range of the drying temperature can be greatly expanded. Therefore, it is possible to expect a dramatic improvement in productivity.

Further, in the heat-sensitive recording material of the present invention, the dimerized or trimerized urea compound used has extremely low solubility in an organic solvent, and even if it is brought into contact with a solvent other than an alcohol type solvent. In addition, the image area hardly disappears or the background color does not change, and the stability to the solvent is high. Therefore, discoloration due to the oil-based ink does not occur.

The present inventors have found that a large number of dimerizations, or 3
Regarding quantified urea compounds, we are investigating the thermal decomposition temperature and the solubility in solvents, etc., and paying attention to the fact that the thermal decomposition temperature and the solubility in solvents can be controlled by selecting the joint group that is the binding site, and further research is conducted. Then, the dimerized urea compound represented by the general formula (1) or (3), or the dimerized urea compound represented by the general formula (2) or (4)
Using a quantified urea compound as a color developer, in a heat-sensitive recording material characterized by using at least one kind, by applying a constant amount of heat by a heat roll, thermal head, hot stamp, or a laser, The recorded image can be erased by irradiating it with light from a halogen lamp or by bringing it into contact with an alcohol solvent such as methanol or ethanol, and a thermal head or laser can be attached to the erased surface. It was possible to re-record by applying a minus sign, that is, a recording medium having reversible recording property was found.

Regarding the reversible recording material, a good thing in terms of decoloring by heat roll is that the substituent (X) of the urea structure at the terminal of the molecule has 3 to 5 carbon atoms which is substituted or unsubstituted.
Alkyl group (eg, A-3, A-5, A-8, etc.), substituted or unsubstituted benzyl group (eg, A-39, A-42, A-45, etc.), or substituted or unsubstituted A recording material using a urea compound such as a phenylethyl group (for example, A-40, A-43, A-47, etc.) as a developer is mentioned.

A heat-sensitive recording material containing these urea compounds as a color-developing agent is subjected to color development by a thermal head or the like.
The color can be erased by bringing it into contact with a heat roll at 00 ° C to 200 ° C, and this decolorized surface can be printed again with a thermal head or the like. For example, those using the exemplified compounds such as A-5, A-15, A-39 and A-40 as the color developer showed good results.

The dimerized or trimerized urea compound used in the present invention by itself has a high developing ability as a developing agent in a thermosensitive recording medium, and this compound together with an electron-donating dye precursor is used as a support. The coated surface coated on top shows the basic characteristics that it does not substantially develop color even at 120 ° C, and the background color has excellent solvent resistance. In addition, the urea compounds of the present invention can be added to other compounds depending on the choice of joint group.
Some have a function of heat resistance of the background color of ℃ or more or reversible recording property (coloring / decoloring property). These properties are new properties that have not been known so far, and these urea compounds are excellent materials that have the properties of color developing property and decoloring property even though they are single color developing agents. is there.

A general method for producing the heat-sensitive recording material of the present invention has (a) a dye precursor and (b) a dimerized urea compound or a trimerized urea compound as a developer having a dispersing function. This is a method in which each is dispersed together with a binder, an auxiliary agent such as a filler or a lubricant is added if necessary to prepare a coating liquid, and the coating liquid is applied onto a support by a usual method and dried. In addition, the dimerized urea compound or the trimerized urea compound of the present invention may be used alone or in combination.

As the dye precursor used in the heat-sensitive recording material of the present invention, those conventionally known in the field of heat-sensitive recording can be used, and although not particularly limited, triphenylmethane leuco dyes, Fluoran-based leuco dyes and fluorene-based leuco dyes are preferred. Hereinafter, typical dye precursors will be exemplified.

3,3-bis (4'-dimethylaminophenyl)
-6-Dimethylaminophthalide (also known as crystal violet lactone (CVL)) 3,3-bis (4'-dimethylaminophenyl) -6-pyrrolidylphthalide 3,3-bis (4'-dimethylamino) Phenyl) phthalide (also known as malachite green lactone (MGL)) tris [4- (dimethylamino) phenyl] methane (also known as leuco crystal violet (LCV)) 3-dimethylamino-6-methyl-7- (m -Trifluoromethylanilino) fluorane 3-diethylamino-6-methyl-fluorane 3-diethylamino-7-methyl-fluorane 3-diethylamino-7-chloro-fluorane 3-diethylamino-6-methyl-7-chlorofluorane 3- Diethylamino-6-methyl-7-anilinofluorane 3-diethylamino-6-methyl-7-p-methylanilinofluorane 3-diethylamino-6-methyl-7- ( o, p-Dimethylanilino) fluorane 3-diethylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane 3-diethylamino-6-methyl-7- (o-chloroanilino) fluorane 3-diethylamino-6 -Methyl-7- (p-chloroanilino) fluorane 3-diethylamino-6-methyl-7- (o-fluoroloanilino) fluorane 3-diethylamino-6-methyl-7- (pn-butylanilino)
Fluorane 3-diethylamino-6-methyl-7-n-octylaminofluorane 3-diethylamino-6-chloro-7-anilinofluorane 3-diethylamino-6-ethoxyethyl-7-anilinofluorane 3-diethylamino- Benzo [a] fluorane 3-diethylamino-benzo [c] fluorane 3-diethylamino-6-methyl-7-benzylaminofluorane 3-diethylamino-6-methyl-7-dibenzylaminofluorane 3-diethylamino-7-di (P-Methylbenzyl) aminofluorane 3-diethylamino-6-methyl-7-diphenylmethylaminofluorane 3-diethylamino-7-dinaphthylmethylaminofluorane 10-diethylamino-4-dimethylaminobenzo [a] fluorane 3 -Dibutylamino-6-methyl-fluorane 3-dibutylamino-6-methyl-7-chlorofluorane 3-dibutylamino-6- Methyl-7-anilinofluorane 3-dibutylamino-6-methyl-7-p-methylanilinofluorane 3-dibutylamino-6-methyl-7- (o, p-dimethylanilino) fluorane 3-dibutyl Amino-6-methyl-7- (m-trifluoromethylanilino) fluorane 3-dibutylamino-6-methyl-7- (o-chloroanilino) fluorane 3-dibutylamino-6-methyl-7- (p-chloroanilino ) Fluoran 3-dibuethylamino-6-methyl-7- (o-fluoroloanilino) fluorane 3-dibuethylamino-6-methyl-7- (pn-butylanilino) fluoran 3-dibutylamino-6-methyl- 7-n-octylaminofluorane 3-dibutylamino-6-chloro-7-anilinofluorane 3-dibutylamino-6-ethoxyethyl-7-anilinofluorane 3-din-pentylamino-6-methyl -7- Anilinofluorane 3-di n-pentylamino-6-methyl-7- (o, p-di Methylanilino) fluorane 3-di n-pentylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane 3-di n-pentylamino-6-methyl-7- (o-chloroanilino) fluorane 3-di n-Pentylamino-6-methyl-7- (p-chloroanilino) fluorane 3-di n-pentylamino-6-methyl-7- (o-fluoroloanilino) fluorane 3-pyrrolidino-6-methyl-7- Anilinofluorane 3-piperidino-6-methyl-7-anilinofluorane 3- (N-methyl-Nn-propylamino) -6-methyl-7-anilinofluorane 3- (N-ethyl-Nn- Propylamino) -6-methyl-7-anilinofluorane 3- (N-ethyl-N-iso-propylamino) -6-methyl-7-
Anilinofluorane 3- (N-ethyl-Nn-butylamino) -6-methyl-7-anilinofluorane 3- (N-ethyl-N-iso-butylamino) -6-methyl-7-anilino Fluoran 3- (N-ethyl-Nn-hexylamino) -6-methyl-7-p-
Methylanilinofluorane 3- (N-ethyl-Nn-hexylamino) -6-methyl-7- (o,
p-Dimethylanilino) fluorane 3- (N-ethyl-Nn-hexylamino) -6-methyl-7- (m-
Trifluoromethylanilino) fluorane 3- (N-ethyl-Nn-hexylamino) -6-methyl-7- (o-
Chloroanilino) fluorane 3- (N-ethyl-N-iso-amylamino) -6-methyl-7-anilinofluorane 3- (N-ethyl-N-iso-amylamino) -6-chloro-7-anilinoflu Oran 3- (N-ethyl-N-3-methylbutylamino) -6-methyl-7
-Anilinofluoran 3- (N-ethyl-Np-toluidino) -6-methyl-7-anilinofluoran 3- (N-ethyl-Np-toluidino) -6-methyl-7- (p-methylanilino) Fluoran 3- (N-ethyl-Np-toluidino) -6-methyl-7- (o, p-dimethylanilino) fluoran 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-
Methyl-7-anilinofluorane 3- (N-cyclohexyl-N-methylamino) -6-methyl-7
-Anilinofluorane 3- (N-cyclohexyl-N-methylamino) -7-anilinofluorane 3- (N-ethyl-N-3-methoxypropylamino) -6-methyl-7-anilinofluorane 3- (N-Ethyl-N-3-ethoxypropylamino) -6-methyl-7-anilinofluorane 2- (4-oxahexyl) -3-dimethylamino-6-methyl
-7- Anilinofluorane 2- (4-oxahexyl) -3-diethylamino-6-methyl
-7- Anilinofluorane 2- (4-oxahexyl) -3-dipropylamino-6-methyl-7-anilinofluorane 3- (4``-aminostilbrudil-4'-amino)- 7,8-Benzofuran 3,6,6'- Tris (dimethylamino) spiro [fluorene
-9,3'-phthalide] 3,6,6'-tris (diethylamino) spiro [fluorene
-9,3'-phthalide] 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide 3- (4-diethylamino- 2-Ethoxyphenyl) -3- (1-octyl-2-methylindol-3-yl) -4-azaphthalide 3- (4-diethylamino-2-n-hexylphenyl) -3- (1-
Ethyl-2-methylindol-3-yl) -4-azaphthalide 3- (4-cyclohexylmethylamino-2-methoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -Four-
Azaphthalide 3- (4-cyclohexylethylamino-2-methoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-
Azaphthalide 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide 3,3-bis (2-methyl-1-octylindol-3-yl)
Phthalide 3- (1-Ethyl-2-methylindol-3-yl) -3- (1-
n-Butyl-2-methylindol-3-yl) phthalide 3,7-bis (dimethylamino) -10-benzoylphenothiazine 3,7-bis (dimethylamino) -N- [pN-bis (4,4 '-Dimethylaminophenyl) methylamino] benzoylphenothiazine 3,7-bis (dimethylamino) -N- [pN-bis (4,4'-diethylaminophenyl) methyl] benzoylphenothiazine 3,6-bis (diethylamino) fluorane- γ- (2'-nitro) anilinolactam 3,6-bis (diethylamino) fluorane-γ- (3'-nitro) anilinolactam 3,6-bis (diethylamino) fluorane-γ- (4'-nitro) Anilinolactam 3,6-bis (diethylamino) fluorane-γ-anilinolactam

These dye precursors may be used alone or in admixture of two or more. The fluoran dye precursor has high color-developing properties and stability of the background color, especially in view of the basic function of the heat-sensitive recording material, and is therefore preferably used in the present invention. When importance is attached to thermal stability, naturally, a dye precursor having a high melting point and a high decomposition temperature is preferable. When reversible recording is important, dye precursors such as 3-diethylamino-7- (m-trifluoromethylanilino) fluorane that have weak image stability and a structure that can withstand repeated use and have a high decomposition temperature. Is good.

As the binder which can be used in the present invention, fully silicified polyvinyl alcohol having a polymerization degree of 200 to 1900, partially saponified polyvinyl alcohol, carboxy modified polyvinyl alcohol, amide modified polyvinyl alcohol, sulfonic acid modified polyvinyl alcohol,
Butyral modified polyvinyl alcohol, other modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer and ethyl cellulose, cellulose derivatives such as acetyl cellulose, polyvinyl chloride, poly Vinyl acetate, polyacrylamide, polyacrylic ester,
Polyacrylamide, polyacrylic acid ester, polyvinyl butyral, polystyrol and their copolymers, polyamide resin, silicone resin, petroleum resin, terpene resin, ketone resin, coumarone resin can be exemplified. Alcohol binders are desirable in terms of dispersibility, binder properties, and thermal stability of background color. Further, in the case of reversible recording, a binder with little deterioration that can withstand repeated use is preferable. These binders are used in a state of being dissolved in a solvent such as water, alcohol, ketone, ester, hydrocarbon, or emulsified in water or other medium, or dispersed in a paste form, and used together depending on the required quality. You can also do it.

Further, in the present invention, in the case of producing a heat-sensitive recording material having particularly high heat stability of the background color, it is generally preferable not to use a sensitizer. This is because when a sensitizer is used, these are melted at a temperature of about the time of drying, and the dye precursor and the developer are reacted with each other, so that the background color tends to develop. However, on the other hand, since the sensitizer enhances the decoloring property, when decoloring property, that is, reversible recording property is more important than thermal stability of the background color, these may be used. As the sensitizer used for that purpose, 2-di (3-methylphenoxy) ethane,
p-benzylbiphenyl, β-benzyloxynaphthalene, 1-hydroxy-2-naphthoic acid phenyl ester, dibenzyl terephthalate, benzyl p-benzyloxybenzoate, diphenyl carbonate, ditolyl carbonate, 4-biphenyl-p-tolyl Ether, m-terphenyl, 1,2-diphenoxyethane, 1,2-bis (m-tolyloxy) ethane, 1,5-bis (p-methoxyphenoxy) -3-oxapentane, dibenzyl oxalate, oxalic acid Examples thereof include di (p-methylbenzyl) and oxalate di (p-chlorobenzyl).

As the filler used in the present invention, silica, calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, talc, zinc oxide, titanium oxide, zinc hydroxide, aluminum hydroxide, or other inorganic filler, or a polystyrene organic material. Examples include fillers, styrene / butadiene organic fillers, styrene / acrylic organic fillers, hollow organic fillers, and the like.

In addition, release agents such as fatty acid metal salts, lubricants such as waxes, benzophenone-based, benzotriazole-based, cyanoacrylate-based UV absorbers, water-proofing agents such as glyoxal, dispersants, and defoaming agents. Etc. can also be used.

The amount of (a) the dye precursor of the present invention and (b) the dimerized or trimerized urea compound, and the types and amounts of other various components are determined according to the required performance and recording suitability. Although not particularly limited, it is usually 1 to 8 parts of a dimerized or trimerized urea compound and 1 to 20 parts of a filler per 1 part of the dye precursor, and the binder is a total solid content. It is 10 to 25% by weight. When it is used repeatedly like a reversible recording medium, it is desirable that the composition be as simple as possible. These materials are ball mills,
A pulverizer such as an attritor and a sand grinder, or an appropriate emulsifying device is used to atomize the particles to a particle size of several microns or less, and a binder and various additive materials are added to form a coating solution. The target thermosensitive recording medium by applying a coating solution having the above composition to any support such as paper, synthetic paper, non-woven fabric, metal foil, plastic film, plastic sheet, or composite sheet combining these. Is obtained.

Further, an overcoat layer made of a polymer material may be provided on the thermosensitive coloring layer for the purpose of improving the storage stability,
An undercoat layer of a polymeric substance containing a filler may be provided below the heat-sensitive layer for the purpose of increasing the color development sensitivity.

The thermosensitive recording medium of the present invention may be provided with a transparent and strong protective coating by heat-laminating a plastic film by taking advantage of high ground color stability. For example,
Even after thermal recording, a heat-resistant card can be easily prepared using a commercially available simple laminating machine.

Among the heat-sensitive recording materials of the present invention, the recording material having a decoloring function is useful as a reversible recording material (rewrite recording material or rewritable recording material) or as a simple display material. However, in the latter case, it is necessary to record and erase at almost the same speed.

There are two methods of erasing the heat-sensitive recording material of the present invention. One method is a method of erasing a recorded image by heat using a heat roll, a thermal head, a hot stamp, a carbon dioxide gas laser, a semiconductor laser, sunlight, a halogen lamp or the like. For example, in the case of hot rolls, the erasing temperature is between 100 ℃ and 200 ℃, and the feed rate is 8 mm
45mm / sec is suitable. Another method is a method of erasing a recorded image by bringing it into contact with an alcohol solvent.

The heat-sensitive recording material of the present invention may be made into an optical recording material by incorporating a light absorbing agent which absorbs light into heat into the heat-sensitive recording layer. The light absorber is not particularly limited as long as it is a substance that absorbs the emission wavelength of various light sources.

For example, when a light source having a continuous wavelength, a strobe flash or the like is used as a light source for recording, the light absorber is described in JP-A-2-206583 and Japanese Patent Application No. 5-30954. Examples include heating reaction products of thiourea derivatives / copper compounds, graphite described in JP-A-3-86580, copper sulfide, lead sulfide, molybdenum trisulfide, black titanium, carbon black, and the like.

On the other hand, when a semiconductor laser is used as a light source for recording, it is used as a light absorber in JP-A-54-4142.
JP-A-58-94494, JP-A-58-209594, JP-A-2-217287, JP-A-3-73814, etc., polymethine dyes (cyanine dyes),
Azolenium dye, pyrylium dye, thiopyrylium dye, squarylium dye, croconium dye, dithiol complex, mercaptophenol metal complex dye, mercaptonaphthol metal complex dye, phthalocyanine dye, naphthalocyanine dye Examples thereof include dyes, triarylmethane dyes, immonium dyes, diimmonium dyes, naphthoquinone dyes, anthraquinone dyes, and metal complex dyes. Further, the light absorbers mentioned in the case of the light source having a continuous wavelength can be used as well.

Specific examples of the polymethine dye (cyanine dye) include, for example, indocyanine green (manufactured by Daiichi Pharmaceutical Co., Ltd.), NK-2014 (manufactured by Japan Photosensitive Dye Research Institute), NK -2612 (manufactured by Japan Photosensitive Dye Research Institute, Inc.), 1,1,
5,5-tetrakis (p-dimethylaminophenyl) -3-methoxy-1,4-pentadiene, 1,1,5,5-tetrakis (p-diethylaminophenyl) -3-methoxy-1,4-pentadiene, etc. As a squarylium dye, NK-277
2 (manufactured by Japan Photosensitive Dye Research Institute Co., Ltd.) and the like, and as the dithiol complex, toluene dithiol nickel complex, 4-tert-butyl-1,2-benzenedithiol nickel complex, bisdithiobenzyl nickel complex , Bis (4-ethyldithiobenzyl) nickel complex, bis (4-n-propyldithiobenzyl) nickel complex, and the like, and examples of immonium-based dyes or diimmonium-based dyes include
IRG002 (Nippon Kayaku Co., Ltd.), IRG022 (Nippon Kayaku Co., Ltd.)
Manufactured by Yamamoto Chemicals Co., Ltd., and the anthraquinone dye manufactured by IR-750 (Nippon Kayaku Co., Ltd.).
Manufactured) and the like. You may use these light absorbers individually or in mixture of 2 or more types.

These light absorbers are used (a) by simply mixing them in various materials required for an optical recording material, and (b) JP-A-2-
As described in Japanese Patent No. 217287, a method in which a light absorber is melt-mixed in advance and dissolved or dispersed in various materials required for the optical recording medium, or (c) necessary for the optical recording medium The light absorbing agent may be dissolved or dispersed in a solvent in advance in a variety of materials, and the dissolved or dispersed mixture may be used according to the method of use after removing the solvent. Further, the light absorber may be co-dispersed (simultaneous mixture dispersion) with a color developer and / or a sensitizer, or a dye precursor and / or a sensitizer.

The heat-sensitive recording material of the present invention does not change much in basic performance (for example, ground color stability such as heat resistance and solvent resistance) even if it contains a light absorber as an optical recording material. Even an optical recording material could be heat-laminated and toner-recorded. The same applies to the additional function (reversible recording property). However, when a sensitizer was used, the heat resistance tended to decrease.

[0055]

The novel dimerized urea compound or trimerized urea compound according to the present invention is a color developing agent which is excellent in color development as a basic function and is also excellent in ground color stability against heat and solvent. There is also a color developer having a reversible recording property. The clear reasons for ground color stability and reversible recording properties have not yet been clarified. However, it is estimated as follows.

The dimerized urea compound of the present invention, or 3
The structure of the quantified urea compound changes depending on the conditions as shown in the following formula. Since this change is a phenomenon similar to keto / enol tautomerism, it is referred to as keto or enolization here for convenience.

[Chemical 20]

It is considered that an enolization is necessary for the dimerized urea compound or the trimerized urea compound to function as a developer. A high temperature is required for enolization, and the thermal head momentarily reaches a high temperature of 200 to 300 ° C, so the enolization occurs in the urea compound that contacts the thermal head, and the color development function occurs and the dye precursor It is believed that the lactone ring is cleaved to develop color. Therefore, the urea compound does not change until the temperature at which enolization occurs, and the background color remains white because it does not react with the dye precursor, which seems to be the reason for the high heat resistance. Also,
It is considered that the dimerized urea compound or the trimerized urea compound has an increased number of active hydrogens as compared with the monourea compound, so that good color development can be obtained.

On the other hand, if the enol compound thus produced is dissolved for some reason and turned into a keto, it is considered that decoloring may occur, and it is brought into contact with an appropriate temperature and heat quantity or an alcohol solvent. It is thought that keto-induced phenomenon occurs and the color disappears. Since enolization and ketoization occur under completely different conditions, enolization and ketoization can be repeated under each condition, which will enable reversible recording.

Further, the ground color does not change due to the writing of the oil-based ink, because the dimerized urea compound or the trimerized urea compound of the present invention has extremely low solubility in the solvent used in the oil-based ink, and these solvents It is considered that the mixture of the dye precursor and the color developer does not substantially occur even when contacted with the.

[0060]

【Example】

<Synthesis of dimerized urea compound and trimerized urea compound> A dimerized urea compound and a trimerized urea compound were synthesized according to the following synthetic method. A general synthetic method is shown below.

[Synthesis Example 1] A monoisocyanate compound (2.2 eq) was dissolved in ethyl acetate (or acetone). A solution of a diamine compound (1.0 eq) dissolved in ethyl acetate (or acetone) was added dropwise to this solution. After stirring for a predetermined period of time, a precipitate was formed, which was filtered,
It was washed with ethyl acetate, n-hexane, hot water and methanol in this order until one spot was obtained on TLC (thin layer chromatography) to obtain a urea compound.

[Synthesis Example 2] Diisocyanate compound (1.
0 eq) was dissolved in ethyl acetate (or acetone).
A solution of a monoamine compound (2.2 eq) dissolved in ethyl acetate (or acetone) was added dropwise to this solution. After stirring for a predetermined period of time, a precipitate was formed, which was filtered,
The mixture was washed with ethyl acetate, n-hexane, hot water, and methanol in this order until the spot became one spot on TLC to obtain a urea compound.

[Synthesis Example 3] A triisocyanate compound (1.0 eq) was dissolved in ethyl acetate (or acetone). A solution of a monoamine compound (3.3 eq) dissolved in ethyl acetate (or acetone) was added dropwise to this solution.
After stirring for a predetermined time, a precipitate was generated, which was filtered and washed with ethyl acetate, n-hexane, hot water, and methanol in this order until one spot was obtained on TLC to obtain a urea compound.

<Production of Thermosensitive Recording Medium and Reversible Recording Medium> In the following description, parts and% indicate parts by weight and% by weight, respectively.

[Examples 1 to 24] As described below, 3-N, N-diethylamino-6-methyl-7-anilinofluorane (alias: ODB) as a dye precursor was used as a color developer. A thermosensitive recording medium was produced using the dimerized urea compound (or the trimerized urea compound) of the present invention. (See Tables 1 and 2) That is, first, a developer dispersion liquid (A liquid) and a dye precursor dispersion liquid (B liquid) having the following formulations were ground with a sand grinder to an average particle diameter of 1 micron. (Liquid A: Developer Dispersion) Dimeric urea compound (or trimeric urea compound) of the present invention 6.0 parts 10% aqueous solution of polyvinyl alcohol 18.8 parts water 11.2 parts (solution B: dye precursor dispersion) 3-N , N-Diethylamino-6-methyl-7-anilinofluorane (ODB) 2.0 parts 10% polyvinyl alcohol aqueous solution 4.6 parts water 2.6 parts Next, at the following ratio, liquid A (developing agent dispersion liquid), liquid B ( The dye precursor dispersion liquid) and the kaolin clay dispersion liquid were mixed to prepare a coating liquid. Solution A: Developer dispersion 36.0 parts Solution B: Dye precursor dispersion 9.2 parts Kaolin clay (50% dispersion) 12.0 parts Coating solution 6.0 g / m ² on one side of 50 g / m ² base paper
It is coated and dried so that it has a surface area of m ² , and this sheet is treated with a super calendar so that the smoothness is 500 to 600 seconds.
A thermosensitive recording medium was prepared.

[Examples 25 to 28] As described below, thermosensitive recording materials were prepared in the same manner as in Examples 1 to 24, except that the dye precursors shown below other than ODB were used as the dye precursors. . (See Table 3) (Dye precursor) ODB-2: 3-N, N-dibutylamino-6-methyl-7-anilinofluorane CVL: 3,3-bis (p-dimethylaminophenyl) -6-
Dimethylaminophthalide NEW-Blue: 3- (4-Diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-
Azaphthalide I-red: 3,3-bis (1-ethyl-2-methylindole)
-3-yl) phthalide That is, first, the dispersion liquid (C liquid) of the above dye precursor having the following composition was ground to an average particle size of 1 micron with a sand grinder. (Liquid C: Dye Precursor Dispersion) 2.0 parts of the above dye precursor 10% aqueous solution of polyvinyl alcohol 4.6 parts water 2.6 parts Next, at the following ratio, the developer dispersion used in Example 2 (Compound A-5 Dispersion liquid), C liquid (dye precursor dispersion liquid),
And the dispersion liquid of kaolin clay was mixed to prepare a coating liquid. The developer dispersion of Example 2 using the compound A-5 36.0 parts C liquid: dye precursor dispersion 9.2 parts Kaolin clay (50% dispersion) 12.0 parts This coating solution was applied to a base paper of 50 g / m ² . Coating amount on one side 6.0g /
It is coated and dried so that it has a surface area of m ² , and this sheet is treated with a super calendar so that the smoothness is 500 to 600 seconds.
A thermosensitive recording medium was prepared.

[Comparative Examples 1 to 7] As described below, thermal recording materials for Comparative Examples were prepared in the same manner as in Examples 1 to 24 by using the following known compounds as color developers. . (See Table 2) (Known developer compound) Bisphenol A (B1) Bisphenol S (B2) 4-Hydroxy-4'-iso-propoxydiphenyl sulfone (B3) 4-Hydroxy-4 ' -n-butyroxydiphenyl sulfone (B
4) Phenylurea (B5) described in JP-A-58-211496, dimerized urea (B6) described in JP-A-5-147357, amidophenol derivative (B7)

[0068]

[Chemical 21]

That is, a dispersion of each of the known developer compounds shown below having the following formulation was ground with a sand grinder to an average particle size of 1 micron. (D liquid: developer dispersion) Known developer compound (B1 to B7) 6.0 parts 10% polyvinyl alcohol aqueous solution 18.8 parts water 11.2 parts Next, at the following ratio, liquid D (developing liquid dispersion), Dispersion liquid (B) of the dye precursor (ODB) used in Examples 1 to 24
Liquid) and a kaolin clay dispersion liquid were mixed to prepare a coating liquid. Liquid D: Developer dispersion 36.0 parts Liquid B: Dye precursor dispersion (ODB dispersion) 9.2 parts Kaolin clay (50% dispersion) 12.0 parts This coating liquid on one side of a 50 g / m ² base paper. Coating amount 6.0g /
It is coated and dried so that it has a surface area of m ² , and this sheet is treated with a super calendar so that the smoothness is 500 to 600 seconds.
A thermosensitive recording medium was prepared.

[Comparative Examples 8 to 9] Bisphenol A was used as the color developer, and ODB-2 and NEW-BLUE were used as the dyes, in the same manner as in Examples 25 to 28. A thermosensitive recording medium was prepared. (Refer to Table 3) <Evaluation of thermal recording medium and reversible recording medium> For the obtained thermal recording medium, first, in order to examine the basic performance, a recording test by a thermal printer, thermal stability of ground color were conducted. A property test and an oil-based ink suitability test were conducted.

[Recordability Test (Dynamic Color Density)]: In order to check recording suitability, a word processor (RUPO-90F (manufactured by Toshiba)) was used and recording was performed on the prepared thermal recording medium with the maximum applied energy. The recording section of the Macbeth densitometer (RD-9
14. An amber filter was used. Hereinafter, the concentration measurement was performed under these conditions. ). In this case, the larger the Macbeth value, the higher the recording density and the better the recording suitability.

[Ground color thermal stability test (static color density)]: 90% to check the thermal stability of the ground color of the recording sheet.
℃, 120 ℃, 150 ℃, each 10g / cm ² on the heating plate heated
The thermosensitive recording medium thus prepared was pressed for 5 seconds under the pressure of, and the recording medium was measured with a Macbeth densitometer. In this case, the smaller the Macbeth value, the lower the degree of coloring of the ground color and the higher the thermal stability of the ground color.

[Oil-based ink suitability test (ground-color discoloration test with oil-based ink)]: Oil-based red magic ink No. 500
(Manufactured by Teranishi Chemical Co., Ltd.) was used to write on the prepared thermosensitive recording medium, and the degree of discoloration with respect to the original red color was visually measured. ◎ ... No discoloration ○ ... Almost no discoloration △ ... Slightly discolored × ... Remarkably discolored

Examples 1 to 28 using the dimerized or trimerized urea compound of the present invention as a developer, and Comparative Examples 1 to 9 using a known developer compound as a developer.
Tables 1 to 3 show the results of evaluating the basic performance of the above.

[0075]

[Table 1]

[Table 2]

[Table 3]

Next, a thermal lamination test and a reversible recording property test were conducted on the obtained thermosensitive recording medium in order to investigate additional performance.

[Thermal laminate test (production of laminar recording material)]: Simple laminator (MS Pouch H-140)
The thermosensitive recording material thus obtained was sandwiched between pouch films using Meiko Shokai Co., Ltd. to prepare a laminated thermosensitive recording material, and its ground color part was measured by a Macbeth densitometer. In this case, the smaller the Macbeth value is, the more stable the ground color is. In other words, it is shown that the lamination can be performed without causing the color development. The thermosensitive recording medium using the dimerized or trimerized urea compound of the present invention was capable of laminating while the ground color remained stable.

[Reversible recording test]: Similar to the recording test, the obtained thermosensitive recording medium was recorded by a word processor, and the recorded thermosensitive recording medium was transferred between heat rolls of 180 ° C. It was passed at a speed of 30 mm / sec, and the recorded part and the ground color part were measured with a Macbeth densitometer. In this case, it is shown that the smaller the Macbeth density of the recording portion, the higher the decoloring property.
After that, the recording was performed again by the above-mentioned word processor and the Macbeth density of the recording portion was measured.

The additional performance of the examples using the dimerized or trimerized urea compound of the present invention as the developer and Comparative Examples 1 to 9 using the known developer compound as the developer The evaluation results are shown in Tables 4-6.

[0080]

[Table 4]

[Table 5]

[Table 6]

[Example 29] With respect to the thermosensitive recording medium of Example 2, a reversibility test by a heat roll was repeated 100 times. The Macbeth densities at the 100th recording and the background color were 1.03 and 0.07.

Example 30 The heat-sensitive recording material of Example 13 was repeatedly subjected to a reversibility test using a heat roll 100 times. The Macbeth densities of the recorded part and the ground color part at the 100th time were 1.00 and 0.09.

Example 31 The heat-sensitive recording material of Example 25 was repeatedly subjected to a reversibility test using a heat roll 100 times. The Macbeth densities of the recorded part and the ground color part at the 100th time were 1.04 and 0.07.

[Example 32] The thermosensitive recording medium of Example 27 was repeatedly subjected to a reversibility test using a heat roll 100 times. The Macbeth densities of the recorded part and the ground color part at the 100th time were 0.81 and 0.08.

[Example 33] In the thermosensitive recording medium of Example 3, after recording with a word processor, the recording surface was wiped with ethanol, and the Macbeth density of the recording portion was measured.
It was 0.20.

[Example 34] In the thermosensitive recording medium of Example 8, after recording with a word processor, the recording surface was wiped with ethanol and the Macbeth density of the recording portion was measured.
It was 0.21.

[Embodiment 35] Toner recording was performed on the heat-sensitive recording material of Embodiment 2 with a copying machine (NP6060 Canon Co., Ltd.). As a result, no change was observed in the ground color and printing was performed. We were able to.

[Example 36] Toner recording was carried out on a thermosensitive recording medium of Example 13 using a copying machine (NP6060 Canon Co., Ltd.). As a result, no change was observed in the ground color and printing was performed. We were able to.

[Example 37] Toner recording was performed on the thermosensitive recording medium of Example 14 using a copying machine (NP6060 Canon Co., Ltd.). As a result, no change was observed in the ground color, and printing was performed. We were able to.

[Embodiment 38] Toner recording was carried out on the heat-sensitive recording material of Embodiment 24 using a copying machine (NP6060 Canon Co., Ltd.). We were able to.

<Production of Optical Recording Material> [Examples 39 to 41] As a dye precursor, 3-
N, N-diethylamino-6-methyl-7-anilinofluorane (also known as ODB) is used as a developer, the dimerized urea compound (or trimerized urea compound) of the present invention, and a light absorber. An optical recording material was produced using a hot melt of the bisdithiobenzyl nickel complex and a sensitizer (light absorber A). (See Table 7.) That is, first, 6 parts of a bidithiobenzyl nickel complex was added to 94 parts of 4-biphenyl-p-tolyl ether, and
The mixture was heated to 150 ° C., melt-mixed, and then pulverized to obtain a light absorber. Then, the light absorbent dispersion having the following composition was ground to an average particle size of 1 micron with a sand grinder. (Liquid E: Light absorber dispersion) Light absorber 4.0 parts 10% polyvinyl alcohol aqueous solution 10.0 parts Water 6.0 parts Then, the developer dispersions (liquid A) used in Examples 1 to 24 at the following ratios. ), The dispersion liquid (B liquid) of the dye precursor (ODB) used in Examples 1 to 24, the E liquid (a light absorbent dispersion liquid), and the kaolin clay dispersion liquid were mixed to prepare a coating liquid. Liquid A (developer dispersion liquid) 36.0 parts Liquid B (dye precursor dispersion liquid) 9.2 parts Liquid E (light absorber dispersion liquid) 20.0 parts Kaolin clay (50% dispersion liquid) 12.0 parts This coating liquid 50 g / m Coating amount 6.0g / on one side of base paper ²
It is coated and dried so that it has a surface area of m ² , and this sheet is treated with a super calendar so that the smoothness is 500 to 600 seconds.
An optical recording material was produced.

[Examples 42 to 43] As a light absorber, NK-2612 (manufactured by Japan Photosensitive Dye Research Institute Co., Ltd.) (light absorber was used instead of a hot melt of a bisdithiobenzylnickel complex and a sensitizer). An optical recording material was produced using B). (See Table 7) First, the following light absorbing aqueous solution was prepared. (F liquid: light-absorbing aqueous solution) NK-2612 0.04 parts Water 3.96 parts Next, the developer dispersion liquid (A liquid) used in Examples 1 to 24 and the developer dispersion liquids used in Examples 1 to 24 at the following ratios. The dye precursor (ODB) dispersion liquid (B liquid), the E liquid (light absorber dispersion liquid), and the kaolin clay dispersion liquid were mixed to prepare a coating liquid. Liquid A (developer dispersion liquid) 36.0 parts Liquid B (dye precursor dispersion liquid) 9.2 parts Liquid F (light absorbing aqueous solution) 4.0 parts Kaolin clay (50% dispersion liquid) 12.0 parts This coating liquid 50 g / m ² Coating amount 6.0g / on one side of the base paper
It is coated and dried so that it has a surface area of m ² , and this sheet is treated with a super calendar so that the smoothness is 500 to 600 seconds.
An optical recording material was produced.

[Examples 44 to 45] As a light absorber, a toluenedithiol nickel complex (light absorber C) was used in place of a hot melt of a bisdithiobenzylnickel complex and a sensitizer, and an optical recording material was obtained. Was manufactured. First, the light absorbing developer dispersion (G liquid) was ground with a sand grinder to an average particle size of 1 micron. (G liquid: light absorbing developer dispersion) Compound A-5 (or Compound A-42) 6.0 parts Toluene dithiol nickel complex 1.0 part 10% polyvinyl alcohol aqueous solution 18.8 parts Water 10.2 parts Then, the following ratio And the light-absorbing developer dispersion (G
Liquid), the dispersion liquid (C liquid) of the dye precursor (NEW-Blue) used in Example 27, and the dispersion liquid of kaolin clay were mixed to prepare a coating liquid. Liquid G (light-absorbing developer dispersion) 36.0 parts Liquid C (dye precursor dispersion) 9.2 parts Kaolin clay (50% dispersion) 12.0 parts This coating solution is applied to one side of 50 g / m ² base paper. Quantity 6.0g /
It is coated and dried so that it has a surface area of m ² , and this sheet is treated with a super calendar so that the smoothness is 500 to 600 seconds.
An optical recording material was produced.

<Evaluation of Optical Recording Material> A recording property test was performed on the obtained optical recording material. [Recordability test (optical recording)]: A laser plotter device described in Japanese Patent Laid-Open No. 3-239598 was used to irradiate an optical recording medium with laser light, and the recording portion was recorded with Macbeth. It was measured with a densitometer. As the light irradiation conditions, a semiconductor laser LT015M with an oscillation wavelength of 830 nm and an output of 30 mW was used as a recording light source.
An aspherical plastic lens with a numerical aperture of 0.45 and a focal length of 4.5 mm using D (Sharp Co., Ltd.) as a light collecting lens.
Recording speed of 50mm / s using AP4545 (Konica Corp.)
ec, recording interval was 50 microns, and solid recording of 1 cm in length and width was obtained. The evaluation results are shown in Table 7.

[0095]

[Table 7]

[0096]

As described above, the dimerized urea compound or the trimerized urea compound of the present invention is
It is an epoch-making developer that can obtain a practical image density recording with a thermal head, etc., even though the background color does not substantially change at ambient temperatures in the range of ~ 150 ° C. I understand. Therefore, the following points can be mentioned as effects of the present invention.

(1) A heat-sensitive recording material having excellent storage stability such as heat resistance and solvent resistance as compared with the conventional heat-sensitive recording material. (2) The thermosensitive recording medium can be used under severe conditions that could not be used until now (for example, temperature conditions in the range of 90 ° C to 150 ° C). (3) Since discoloration does not occur when writing with an oil-based ink, it is possible to freely write on a thermosensitive recording medium using these writing tools. (4) It is possible to easily heat-laminate the thermosensitive recording medium by using a simple laminator or the like. Cards can be easily made. (5) Toner recording can be carried out on the thermosensitive recording medium because the ground color is stable even after passing through a heat roll.

Further, with respect to the thermosensitive recording medium having the color erasing function, (6) a new recording system capable of repeating recording / erasing with a color tone is possible and can be used many times, which saves resources. (7) Some of them can be erased only by passing them through a heat roll, and no strict temperature control is required at the time of erasing. (8) Unlike liquid crystals, it can be used as a simple display for recording / erasing using different thermal energy. Further, the same effect can be expected when the heat-sensitive recording material of the present invention is made to contain a light absorber as an optical recording material.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisami Satake 5-21-1 Oji, Kita-ku, Tokyo Inside Nippon Paper Industries Co., Ltd.

Claims (7)

[Claims] 1. A thermosensitive recording medium having a thermosensitive color developing layer comprising a colorless or light-colored dye precursor and a developer which reacts when heated to develop a color of the dye precursor, wherein the developer has a general formula: The urea compound represented by (1) or (2), wherein the thermosensitive coloring layer comprises at least one of the urea compounds.
A thermal recording material containing at least one kind. [Chemical 1] (Here, X is a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 14 carbon atoms. Y represents a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a halogen atom, or a hydrogen atom.
Further, A represents a divalent group having 30 or less carbon atoms, and B represents a trivalent group having 30 or less carbon atoms. ) 2. A thermosensitive recording medium having a thermosensitive color developing layer comprising a colorless or light-colored dye precursor and a developer which reacts when heated to develop the color of the dye precursor, wherein the developer has the following general formula: A thermal recording material, which is a urea compound represented by the formula (3) or (4), wherein the thermosensitive coloring layer contains at least one kind of the urea compound. [Chemical 2] (Here, X is a substituted or unsubstituted C1-C18 alkyl group, a substituted or unsubstituted C3-C10 cycloalkyl group, or a substituted or unsubstituted C7-C14 aralkyl group. Y represents a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a halogen atom, or a hydrogen atom.
A ₁ is S, O, SO ₂ , CH ₂ , CH ₂ CH ₂ , C
(CH) ₂ , C (= O), NH, NHC (= O) are represented, and B ₁ is CH, PO ₃ . ) 3. An optical recording medium, wherein the recording layer of the heat-sensitive recording medium according to claim 1 or 2 contains a light absorbing agent that absorbs light and converts it into heat. 4. A thermal recording card obtained by laminating the thermal recording medium according to claim 1 or 2 or the optical recording medium according to claim 3 with a plastic film. 5. A transfer sheet for electrophotography, which uses the heat-sensitive recording material according to claim 1 or 2, or the optical recording material according to claim 3. 6. After recording on the thermal recording medium according to claim 1 or 2, or the optical recording medium according to claim 3, heat is applied to the recording portion to erase the recorded image, and thermal recording is performed again. A reversible recording method characterized by the above. 7. After recording on the heat-sensitive recording material according to claim 1 or 2, or the optical recording material according to claim 3, a recording image is erased by contacting the recording portion with an alcohol solvent. , A reversible recording method characterized by performing heat-sensitive recording again.