JPH05278342A - Thermal recording material - Google Patents

Abstract

PURPOSE:To improve chemical resistance, plasticity resistance, water resistance, and a coloring property by a method wherein after applying application liquid which dissolves a specific dye precursor, a coloration agent and ionizing radiation setting resin onto a base material, it is hardened and a thermal recording layer is laminated. CONSTITUTION:An application liquid for a thermal recording layer is prepared by dispersing respective specific amounts of a dye precursor expressed by the formula I (Ra represents a C4-C12 tertiary alkyl group, R1-R11 represent a hydrogen, a halogen, a C1-C2 alkyl group, an alkoxyl group, a hydroxyl group, etc.), a coloration agent, and ionizing radiation setting resin in a specific solvent. After applying or printing the application liquid onto a base material of paper, a plastic film, synthetic paper, etc., it is irradiated with ionizing radiation to harden the application liquid, and a thermal recording layer is formed to make a thermal recording material. As an example of the abovementioned coloration agent, there are an aromatic carboxylic acid derivative, a phenol derivative, etc. Further, as an example of the ionizing radiation setting resin, there are 2-6 valencies polyhydric alcohol, poly (metha) acrylate of polyalkylene glycol, etc.

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, and more particularly to a heat-sensitive recording material having high whiteness, excellent chemical resistance, plasticizer resistance and water resistance, and excellent color development. ..

[0002]

2. Description of the Related Art A thermosensitive recording medium which utilizes a color reaction between a colorless or light-colored dye precursor and an organic or inorganic acidic substance to bring both colored substances into contact with each other by heat to obtain a recorded image is well known. ing. Recently, with the remarkable progress of the thermal recording system, its fields of use and forms are diversifying, and it is necessary not only as a recording medium for a thermal facsimile or a thermal printer, but also a magnetic thermal recording paper, a POS label, and forgery prevention. Ticket cards, prepaid cards,
The use for new uses such as sealless commuter passes is also increasing rapidly.

However, the thermal recording material generally does not have sufficient chemical resistance, and the image portion may be discolored due to the influence of fingerprints, diazo copy, cellophane tape, felt-tip pen, ink, etc., or it may come into contact with a synthetic resin product for a long time. However, the plasticizer contained in the synthetic resin has a defect that the image is discolored or the white paper portion is colored, and the commercial value thereof is significantly impaired, and improvement is strongly demanded.

Therefore, it has been attempted to provide a protective layer of a water-soluble polymer on the heat-sensitive recording layer to improve the defects caused by chemicals and plasticizers, and it is partially used for POS labels, ticket, etc. There is. However, since such a protective layer contains a water-soluble polymer as a main component, the water resistance is inferior, and a satisfactory thermosensitive recording medium has not been obtained. On the other hand, in a thermosensitive recording medium having no protective layer, not only the storage stability of the recorded image as described above is poor, but also the water resistance is poor due to the use of a water-soluble polymer as an adhesive, so that the thermosensitive recording medium is not sensitive to heat when contacted with water. Peeling or elution of the recording layer occurs, which is a major drawback.

In order to improve such drawbacks, a recording layer is formed by using a coating solution prepared by using a specific dye precursor and a melting point depressant and using an organic solvent as a medium. There has been proposed a method of forming with a coating liquid using as a medium (JP-A-63-315290). However, the dye precursor used here is industrially expensive and is not always an advantageous method.

Further, a heat-sensitive recording layer using an organic solvent as a medium generally has a low whiteness and has a drawback that the commercial value is remarkably reduced.

[0007]

DISCLOSURE OF THE INVENTION The present invention has improved various drawbacks as described above, has a high degree of whiteness, does not cause discoloration of an image area or white paper area due to chemicals or plasticizers, and It is intended to provide a high-sensitivity heat-sensitive recording material which is excellent in water resistance and does not cause peeling or elution of the recording layer even when contacted with water.

[0008]

SUMMARY OF THE INVENTION The present invention comprises:
At least one of the dye precursors represented by [Chemical Formula 1], [Chemical Formula 2] and [Chemical Formula 3], a color former capable of coloring the dye precursor,
And a thermosensitive recording medium characterized in that after a coating liquid for a recording layer containing an ionizing radiation curable resin is applied, the coating liquid is cured by ionizing radiation.

[0009]

[Chemical 1]

[Wherein Ra is C_Four~ C₁₂The tertiary alkyl
Group, R₁~ R₁₁Are hydrogen atom and halogen atom, respectively
Child, C₁~ C₁₂Alkyl group of C₁~ C₁₂The alkoxy
Group, hydroxyl group, nitro group, -N (R₁₂) (R₁₃), -O
(CO) OR₁₄, Or -O (CO) R₁₅Indicates. However,
R₁₂, R₁₃Are hydrogen atoms; C₁~ C₁₂The alkyl
Group; C_Four~ C₁₂Cycloalkyl group; halogen atom, C
₁~ C₆Alkyl group of C ₁~ C₆With the alkoxyl group of
Optionally substituted aralkyl group; halogen atom, C₁
~ C₆Alkyl group of C₁~ C₆Substitute with alkoxyl group
Represents an aryl group which may be represented by R₁₂And R₁₃Are adjacent
Pyrrolidino group, piperidino group or
A xamethyleneimino group may be formed. Also, R₁₄Is
C₁~ C₁₂Alkyl group; benzyl group; halogen atom,
C₁~ C₆Alkyl group of C₁~ C₆Alkoxyl group
Represents an aryl group which may be substituted with₁₅Is C₁~ C
₁₂Alkyl group; benzyl group; halogen atom, C₁~ C
₆Alkyl group of C₁~ C₆Substituted with an alkoxyl group of
Optionally substituted aryl group; -N (R₁₆) (R₁₇) Is shown.
Incidentally, R₁₆, R₁₇Are hydrogen atoms; C₁~ C₁₂The al
Kill group; C_Four~ C₁₂Cycloalkyl group of halogen
Child, C₁~ C₆Alkyl group of C₁~ C₆The alkoxy
Alkyl group which may be substituted with a group; halogen atom
Child, C₁~ C₆Alkyl group of C₁~ C₆The alkoxy
Represents an aryl group which may be substituted with a ₁₆And R
₁₇Is a pyrrolidino group, piperidino together with the adjacent nitrogen atom.
Groups or hexamethyleneimino groups may be formed. ]

[0011]

[Chemical 2]

[In the formula, R b represents a C _{4 to} C ₁₂ tertiary alkyl group, and R _{18 to} R ₃₀ represent a hydrogen atom, a halogen atom, a C _{1 to} C ₁₂ alkyl group, and a C _{1 to} C ₁₂ group, respectively. Alkoxyl group, hydroxyl group, -O (CO) OR ₃₁ or -O (CO)
R ₃₂ is shown. However, R ₃₁ and R ₃₂ are each a C _{1 to} C ₁₂ alkyl group; a benzyl group; a halogen atom, a C _{1 to} C ₆ alkyl group, and an aryl group which may be substituted with a C _{1 to} C ₆ alkoxyl group. Show. ]

[0013]

[Chemical 3]

[Wherein Rc and Rd are C_Four~ C₁₂
Is a tertiary alkyl group. X and Y are> NR₄₁,
Or -S-, but X and Y are connected in the form> NAN <
You may match. Where R₄₁Is a hydrogen atom, C₁~ C_Tenof
Alkyl group, -COR₄₂Or -COOR₄₃And A is
C₁~ C_TenIs a saturated or unsaturated alkylene group.
Also, R₄₂, R₄₃Are each C₁~ C₁₂An alkyl group of
Benzyl group; halogen atom, C₁~ C₆An alkyl group of
C₁~ C₆Which may be substituted with an alkoxyl group of
Represents a radical. Also, R₃₃~ R₄₀Are hydrogen atom and
Rogen atom, C₁~ C_TenAlkyl group of C₁~ C_TenA
Rukoxyl group, nitro group, -N (R₄₄) (R ₄₅), Or-
SR₄₆Indicates. Incidentally, R₃₃And R₃₄, R₃₄And R₃₅, R₃₅And R
₃₆, R₃₇And R₃₈, R₃₈And R₃₉, R₃₉And R₄₀Are each
It may form a Nzen ring. Where R₄₄, R₄₅Is it
Hydrogen atom; C₁~ C₁₂Alkyl group of C_Four~ C₁₂of
Cycloalkyl group; halogen atom, C₁~ C₆The archi
Lu group, C₁~ C₆May be substituted with an alkoxyl group of
Aralkyl group; halogen atom, C₁~ C₆The alkyl
Base, C₁~ C₆Which may be substituted with an alkoxyl group of
Shows reel group, but R ₄₄And R₄₅Together with the adjacent nitrogen atom
A pyrrolidino group, a piperidino group or hexamethylene
A mino group may be formed. Also, R₄₆Is C₁~ C_TenA
Indicates a rukyl group. ]

[0015]

As described above, the heat-sensitive recording material of the present invention uses the specific dye precursor and uses the ionizing radiation curable resin as the main adhesive of the recording layer. Not only is it excellent in resistance to plasticizers, but it also has remarkable effects in terms of whiteness and water resistance.

The above-mentioned specific dye precursor used in the present invention is colorless or light in color, but it develops color when heated at a high temperature, and lowers the color development temperature when coexisted with an acidic substance. it can. In addition, the obtained image is extremely robust and has excellent resistance to temperature, humidity, various chemicals and plasticizers. This is presumed to be because the color development reaction of the dye precursor used in the present invention is an irreversible reaction that includes a decarboxylation reaction and does not return to a colorless compound. Further, in a usual dye precursor, a remarkable fog color is generated when it is contacted with an ionizing radiation-curable resin, but the specific dye precursor used in the present invention does not have such a fear, and has a high whiteness recording layer. Is obtained. And, by the synergistic effect of the characteristics of the dye precursor and the characteristics of the ionizing radiation curable resin,
Even when stored in a high-temperature or high-humidity environment or in contact with a plasticizer, the heat-sensitive recording material can be obtained with extremely low whiteness and very little discoloration of the image and excellent water resistance. Further, it is presumed that a stable tertiary carbonium ion is produced as an intermediate along with the above decarboxylation reaction, and it is considered that this gives a highly sensitive recording material. The heat-sensitive recording material of the present invention has a higher degree of transparency than the conventional heat-sensitive recording material, and is advantageous in that it can be applied to an overhead projector.

Specific examples of the dye precursor represented by the general formula [Chemical Formula 1] include the following. 3,6-di (tert-butoxycarboxy) fluorane, 3,6-di (1,1-dimethylpropoxycarboxy) fluorane, 3,6-di (1-methyl-1-ethylbutoxycarboxy) fluorane, 3,6 -Di (tert-butoxycarboxy) -4,5-dimethylfluorane, 3,6-di (tert-butoxycarboxy) -1,8-dimethylfluorane, 3,6-di (tert-butoxycarboxy)-
2,7-diethylfluorane, 3,6-di (tert-butoxycarboxy) -1,5-diethylfluorane, 3,
6-di (1,1-dimethylpropoxycarboxy)-
2,7-diethylfluorane, 3,6-di (tert-butoxycarboxy) -4,5-dinitrofluorane, 3,
6-di (tert-butoxycarboxy) -2,7-didecylfluorane, 3,6-di (tert-butoxycarboxy) -2-dodecyl-8-methylfluorane, 3,6-
Di (tert-butoxycarboxy) -6'-butoxyfluorane, 3,6-di (tert-butoxycarboxy)-
4'-methoxyfluorane, 3,6-di (tert-butoxycarboxy) -4'-decaoxyfluorane, 3-
(Tert-butoxycarboxy) -6-methoxyfluorane, 3- (tert-butoxycarboxy) -7-methoxyfluorane, 3,6-di (1,1-dimethylpropoxycarboxy) -6'-butoxyfluorane, 3- (tert
-Butoxycarboxy) -6-ethoxy-2,7-dioctylfluorane, 3- (1,1-dipropylbutoxycarboxy) -2,4,5,7-tetrachlorofluorane, 3,6-di (tert -Butoxycarboxy) -2,
4,5,7-Tetrachlorofluorane, 3,6-di (te
rt-Butoxycarboxy) -2,4,5,7-tetrabromofluorane, 3,6-di (tert-butoxycarboxy) -2,4,5,7-tetraiodofluorane, 3,
6-di (tert-butoxycarboxy) -1,8-dimethyl-3 ', 4', 5 ', 6'-tetrachlorofluorane, 3,6-di (tert-butoxycarboxy) -3',
4 ', 5', 6'-Tetrabromofluorane, 3,6-
Di (1,1-dimethylpropoxycarboxy) -2,7
-Dibromofluorane, 3,6-di (1,1-dimethylpropoxycarboxy) -4,5-dinitrofluorane, 3,6-di (1,1-diethylhexaoxycarboxy) -3 ', 4', 5 ', 6'-tetrachlorofluorane, 3,6-di (tert-butoxycarboxy) -2,
7-dibromofluorane, 3- (1,1-dipropylbutoxycarboxy) -6-methoxyfluorane, 3-
(Tert-Butoxycarboxy) -6-ethoxy-2,7
-Dibenzylfluorane, 3- (tert-butoxycarboxy) -6-methoxycarboxyfluorane, 3- (te
rt-Butoxycarboxy) -7-methoxycarboxyfluorane, 3- (tert-butoxycarboxy) -6-decaoxycarboxyfluorane, 3- (tert-butoxycarboxy) -6-dimethylaminofluorane, 3-
(Tert-butoxycarboxy) -6-diethylaminofluorane, 3- (tert-butoxycarboxy) -7-diethylaminofluorane, 3- (tert-butoxycarboxy) -6-dibutylaminofluorane, 3- (tert-
Butoxycarboxy) -6-didodecylaminofluorane, 3- (tert-butoxycarboxy) -6-piperidinofluorane, 3- (tert-butoxycarboxy) -6
-(N-ethyl-N-isopentyl) aminofluorane, 3- (tert-butoxycarboxy) -6- (N-cyclohexyl-N-methyl) aminofluorane, 3-
(Tert-butoxycarboxy) -6-phenoxycarboxyfluorane, 3- (tert-butoxycarboxy)-
6-benzyloxycarboxyfluorane, 3- (1,
1-dimethylhexaoxycarboxy) -6-decaoxycarboxyfluorane, 3- (tert-butoxycarboxy) -6-butylcarboxyfluorane, 3- (tert
-Butoxycarboxy) -6-phenylcarboxyfluorane, 3- (tert-butoxycarboxy) -6-dimethylaminocarboxyfluorane and the like.

Specific examples of the dye precursor represented by the general formula [Chemical Formula 2] include the followings. O,
O'-di (tert-butoxycarbonyl) phenol sulfophthalein, O, O'-di (tert-butoxycarbonyl) -3,3'-dimethylphenol sulfophthalein, O, O'-di (tert-butoxycarbonyl) ) -2,
2'-Dimethyl-5,5'-diisopropylphenolsulfophthalein, O, O'-di (tert-butoxycarbonyl) -3,3 ', 5,5'-tetrabromophenolsulfophthalein, O, O' -Di (tert-butoxycarbonyl) -2,2'-dimethyl-3,3 ', 5,5'
-Tetrabromophenol sulfophthalein, O, O '
-Di (tert-butoxycarbonyl) -3,3'-dibromophenol sulfophthalein, O, O'-di (tert-
Butoxycarbonyl) -3,3'-dibromo-5,5 '
-Dimethylphenol sulfophthalein, O, O'-di (tert-butoxycarbonyl) -2,2'-dimethyl-
3,3′-dibromo-5,5′-diisopropylphenolsulfophthalein, O, O′-di (1,1-diethylhexyloxycarbonyl) phenolsulfophthalein, O- (tert-butoxycarbonyl) -O ′ -Methylphenol sulfophthalein, O, O'-di (1,1
-Dimethylpentyloxycarbonyl) phenolsulfophthalein, O- (tert-butoxycarbonyl) phenolsulfophthalein, O, O'-di (1,1-diethylhexyloxycarbonyl) -3,3'-dibromo-5, 5'-dimethylphenol sulfophthalein, O
-(Tert-butoxycarbonyl) -O'-acetylphenolsulfophthalein, O- (tert-butoxycarbonyl) -O'-benzylcarbonylphenolsulfophthalein, O- (tert-butoxycarbonyl) -O'-
Phenylcarbonylphenol sulfophthalein, O-
(Tert-butoxycarbonyl) -O '-(1,1-dimethylpentyloxycarbonyl) phenolsulfophthalein, O- (tert-butoxycarbonyl) -O'-benzyloxycarbonylphenolsulfophthalein,
O- (tert-butoxycarbonyl) -O'-phenyloxycarbonylphenol sulfophthalein and the like.

Further, specific examples of the dye precursor represented by the general formula [Chemical Formula 3] include the following. O,
O'-di (tert-butoxycarbonyl) indigo white, O, O'-di (tert-butoxycarbonyl) -5-
Bromoindigo white, O, O'-di (tert-butoxycarbonyl) -5,5'-dibromoindigo white, O, O'-di (tert-butoxycarbonyl) -5,
5 ', 7-tribromoindigo white, O, O'-di (tert-butoxycarbonyl) -5,5', 7,7'-
Tetrabromoindigo white, O, O'-di (tert-
Butoxycarbonyl) -4,4 ', 5,5', 7,7 '
-Hexabromoindigo white, O, O'-di (tert
-Butoxycarbonyl) -5,5 ', 7,7'-tetrachloroindigo white, O, O'-di (tert-butoxycarbonyl) -4,4'-dichloroindigo white, O, O'-di (tert -Butoxycarbonyl) -4,
4 ', 5,5'-tetrachloroindigo white, O,
O'-di (tert-butoxycarbonyl) -6,6'-dimethylindigo white, O, O'-di (tert-butoxycarbonyl) -5,5'-difluoroindigo white, O, O'-di (tert -Butoxycarbonyl) -N,
N'-hexamethylene indigo white, O, O'-di (tert-butoxycarbonyl) -N, N'-ethylene indigo white, O, O'-di (tert-butoxycarbonyl) -N, N'-ethenylene Indigo White, O,
O'-di (tert-butoxycarbonyl) -4,4'-dichloro-5,5'-dibromoindigo white, O,
O'-di (tert-butoxycarbonyl) -5,5'-dimethylindigo white, O, O'-di (tert-butoxycarbonyl) -7,7'-dimethylindigo white, O, O'-di (tert -Butoxycarbonyl) -5,
5'-dimethyl-7,7'-dichloroindigo white, O, O'-di (tert-butoxycarbonyl) -6,
6'-diethylindigo white, O, O'-di (tert
-Butoxycarbonyl) -7,7'-didecylindigo white, O, O'-di (tert-butoxycarbonyl)
-6,6'-dimethoxyindigo white, O, O'-
Di (tert-butoxycarbonyl) -6,6'-dinonanoxyindigo white, O, O'-di (tert-butoxycarbonyl) -6,6'-di (ethylthio) indigo white, O, O'-di (Tert-butoxycarbonyl)-
5,5'-dinitroindigo white, O, O'-di (tert-butoxycarbonyl) -5,5'-diaminoindigo white, O, O'-di (tert-butoxycarbonyl) -6,6'-di (N, N-Dimethylamino) indigo white, O, O'-di (tert-butoxycarbonyl) -5,5'-di (N, N-dinonaamino) indigo white, O, O'-di (tert-butoxy) Carbonyl)
-6,6'-dipyrrolidinoindigo white, O, O '
-Di (tert-butoxycarbonyl) -5,5'-di (N
-Phenylamino) indigo white, O, O'-di (tert-butoxycarbonyl) -N, N'-dimethylindigo white, O, O'-di (tert-butoxycarbonyl) -N, N'-diethylindigo white , O,
O'-di (tert-butoxycarbonyl) -N, N'-dioctylindigo white, O, O'-di (tert-butoxycarbonyl) -5,5'-dibromo-N, N'-diethylindigo white, O , O'-di (tert-butoxycarbonyl) -N, N'-diacetylindigo white, O, O'-di (tert-butoxycarbonyl) -N,
N'-dibenzoylindigo white, O, O'-di (tert-butoxycarbonyl) -N, N'-divaleryl indigo white, O, O ', N, N'-tetra (tert
-Butoxycarbonyl) indigo white, O, O ',
N, N'-tetra (tert-butoxycarbonyl) -4,
4'-dichloroindigo white, O, O'-di (1,
1-Dimethylpropoxycarbonyl) indigo white, O, O'-di (1,1-diethylbutoxycarbonyl) indigo white, O, O'-di (1,1-diethylbutoxycarbonyl) -6,6'-dibromoindigo White, O, O'-di (1,1-diethylbutoxycarbonyl) -N, N'-dimethylindigo white, O
-(Tert-Butoxycarbonyl) -O '-(1,1-diethylbutoxycarbonyl) indigo white, 2-
[3 '-(tert-butoxycarbonyloxy) benzothiophen-2'-yl] -3- (tert-butoxycarbonyloxy) indole, 2- [3'-(tert-butoxycarbonyloxy) -5'-bromobenzo Thiophene-2'-yl] -3- (tert-butoxycarbonyloxy) -5-bromoindole, O, O'-di (tert-butoxycarbonyl) thioindigo white, O, O'-
Di (tert-butoxycarbonyl) -5,5'-dichlorothioindigo white, O, O'-di (tert-butoxycarbonyl) -6,6'-dichlorothioindigo white, O, O'-di (tert- Butoxycarbonyl) -5,
5'-dibromothioindigo white, O, O'-di (tert-butoxycarbonyl) -5,5'-diisopropylthioindigo white, O, O'-di (tert-butoxycarbonyl) -7,7'-diisopropyl Thioindigo white, O, O'-di (tert-butoxycarbonyl) -4,4'-dimethyl-6,6'-dichlorothioindigo white, O, O'-di (tert-butoxycarbonyl) -5,5 ′, 7,7′-Tetramethylthioindigo white, O, O′-di (tert-butoxycarbonyl) -5,5′-diaminothioindigo white, O,
O'-di (tert-butoxycarbonyl) -6,6'-di (N, N-dimethylamino) thioindigo white,
O, O'-di (tert-butoxycarbonyl) -5,5 '
-Di (N, N-dinonylamino) thioindigo white, O, O'-di (tert-butoxycarbonyl) -5,
5'-dimethoxythioindigo white, O, O'-di (tert-butoxycarbonyl) -6,6'-diethoxythioindigo white, O, O'-di (tert-butoxycarbonyl) -6,6'- Dioctoxythioindigo white, O, O'-di (tert-butoxycarbonyl)-
5,5'-di-tert-butylthioindigo white,
O, O'-di (tert-butoxycarbonyl) -5,5 '
-Dichloro-7,7'-dimethylthioindigo white, O, O'-di (tert-butoxycarbonyl) -5,
5'-di (ethylthio) thioindigo white, O,
O'-di (tert-butoxycarbonyl) -6,6'-di (ethylthio) thioindigo white, O, O'-di (tert-butoxycarbonyl) -4,4 ', 7,7'-
Tetramethyl-5,5'-dichlorothioindigo white, O, O'-di (tert-butoxycarbonyl) -5,
5'-dibromo-6,6'-diethoxythioindigo white, O, O'-di (tert-butoxycarbonyl)-
4,5-, 4 ', 5'-dibenzothioindigo white, O, O'-di (tert-butoxycarbonyl) -5,
6-, 5 ', 6'-dibenzothioindigo white,
O, O'-di (1,1-dimethylpropoxycarbonyl) thioindigo white, O, O'-di (1,1-dimethylbutoxycarbonyl) thioindigo white,
O, O'-di (1,1-diethylpropoxycarbonyl) thioindigo white, O, O'-di (1,1-diethylpropoxycarbonyl) -5,5'-dichlorothioindigo white, O- (tert- Butoxycarbonyl) -O '-(1,1-diethylbutoxycarbonyl)
Thioindigo white etc.

Of course, the compounds are not limited to these compounds, and if necessary, two or more kinds of dye precursors may be used in combination. Among the dye precursors represented by the above general formulas [Chemical formula 1], [Chemical formula 2] and [Chemical formula 3], Ra and R
The compound in which the substituents represented by b, Rc and Rd are tert-butyl groups is more preferably used because a thermosensitive recording material having particularly excellent color developability can be obtained.

In the present invention, various colorants, such as an aromatic carboxylic acid derivative and a phenol derivative, an organic acidic substance such as an acidic clay, and an inorganic acidic substance, such as an acidic clay, are used as a color forming agent for forming a heat-sensitive recording layer together with a specific dye precursor. Acidic substances can be used. Specific examples of such acidic substances include the following. Benzoic acid, 4-tert-butylbenzoic acid, 4-chlorobenzoic acid, 4-nitrobenzoic acid, phthalic acid, gallic acid, salicylic acid, 3-isopropylsalicylic acid, 3-phenylsalicylic acid, 3-cyclohexylsalicylic acid, 3,5- Di-tert-butylsalicylic acid, 3-
Methyl-5-benzylsalicylic acid, 4-pentyloxysalicylic acid, 4- (3-p-tolylsulfonylpropoxy) salicylic acid, 4- (2-p-methoxy-phenoxyethoxy) salicylic acid, 5- [p- (2-p- Methoxyphenoxyethoxy) cumyl] salicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl) salicylic acid,
3,5-di- (α-methylbenzyl) salicylic acid, 2-
Aromatic carboxylic acid derivatives such as hydroxy-1-benzyl-3-naphthoic acid; 4,4'-isopropylidene diphenol (bisphenol A), 4,4'-isopropylidene bis (2-chlorophenol), 4,4 ′ -Isopropylidene bis (2,6-dichlorophenol), 4,
4'-isopropylidene bis (2,6-dibromophenol), 4,4'-isopropylidene bis (2-methylphenol), 4,4'-isopropylidene bis (2,4)
6-dimethylphenol), 4,4'-isopropylidenebis (2-tert-butylphenol), 4,4'-se
c-butylidene diphenol, 2,2'-bis (4-hydroxyphenyl) -4-methylpentane, 4,4'-
Cyclohexylidene bisphenol, 4,4'-cyclohexylidene bis (2-methylphenol), 4-tert
-Butylphenol, 4-phenylphenol, 4-hydroxydiphenoxide, α-naphthol, β-naphthol, methyl-4-hydroxybenzoate, benzyl-4-hydroxybenzoate, 2,2'-thiobis (4,6-dichlorophenol) , 4-tert-octylcatechol, 2,2'-methylenebis (4-chlorophenol), 2,2'-methylenebis (4-methyl-6-
tert-butylphenol), 2,2'-dihydroxydiphenyl, methyl-bis (4-hydroxyphenyl)
Acetate, ethyl-bis (4-hydroxyphenyl)
Acetate, benzyl-bis (4-hydroxyphenyl) acetate, 4,4 '-(p-phenylenediisopropylidene) diphenol, 4,4'-(m-phenylenediisopropylidene) diphenol, 4-hydroxydiphenylsulfone , 4,4'-dihydroxydiphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone, 4-hydroxy-4'-methyl-diphenyl sulfone, 4-hydroxy-4'-isopropoxydiphenyl sulfone, 4-hydroxy-3 ', 4'-tetramethylene diphenyl sulfone, 3,3'-diallyl-4,4 '
-Phenolic compounds such as dihydroxydiphenyl sulfone; p-phenylphenol-formalin resin, p-
Organic acidic substances such as phenolic resins such as butylphenol-acetylene resin; and these organic acidic substances such as zinc, magnesium, aluminum, calcium,
Salts with polyvalent metals such as titanium, manganese, tin and nickel; metal complex compounds such as antipyrine complexes of zinc thiocyanate. Of course, it is not limited to these, and it is also possible to use two or more kinds together if necessary.

The ratio of the specific dye precursor and the color former used in the heat-sensitive recording layer is not particularly limited, but generally 0.1 to 5 parts by weight per 1 part by weight of the dye precursor.
It is desirable to use 0 parts by weight, preferably 1 to 20 parts by weight of the color former.

In the present invention, the above-mentioned specific compound is used as the dye precursor, but if necessary, a known dye precursor may be used in combination within the range that does not impair the desired effects of the present invention. You can also Specific examples of such dye precursors include the following. 3,3-bis (p
-Dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (4-dimethylaminophenyl) -3-
(4-Diethylamino-2-methylphenyl) -6-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) phthalide, 3- (p-dimethyl Aminophenyl)-
3- (2-methylindol-3-yl) phthalide,
3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,3-bis (9-ethylcarbazol-3-yl) -6-dimethylaminophthalide,
3,3-bis (2-phenylindol-3-yl)-
6-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (1-methylpyrrol-3-yl)
-6-Dimethylaminophthalide, 3- (p-dibenzylaminophenyl) -3- (1,2-dimethylindol-3-yl) -7-azaphthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-
2-Methylindol-3-yl) -7-azaphthalide, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, N-butyl-3- {bis [4-
Triarylmethane compounds such as (N-methylanilino) phenyl] methyl} carbazole, 4,4′-bis (dimethylamino) benzhydrylbenzyl ether,
N-halophenyl-leukoauramine, N-2,4,5
-Diphenylmethane compounds such as trichlorophenyl leuco auramine, 4,4'-bis (dimethylamino) benzhydryl-p-toluenesulfinic acid ester,
3,7-bis (diethylamino) -10-benzoylphenoxazine, benzoylleucomethylene blue, p
-Thiazine compounds such as nitrobenzoyl leuco methylene blue, 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3-phenylspirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho (6'- Methoxybenzo) spiropyran, 3-
Spiro compounds such as propylspirodibenzopyran, di-β-naphthospiropyran, and 3-methyl-di-β-naphthospiropyran, rhodamine-B-anilinolactam,
Lactam compounds such as rhodamine (p-nitroanilino) lactam and rhodamine (o-chloroanilino) lactam, 3-diethylamino-6-methylfluorane, 3-
Dimethylamino-7-methoxyfluorane, 3-diethylamino-6-methoxyfluorane, 3-diethylamino-7-methoxyfluorane, 3-diethylamino-7
-Chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6,7
-Dimethylfluorane, 3- (N-ethyl-p-toluidino) -7-methylfluorane, 3-diethylamino-
7- (N-acetyl-N-methylamino) fluorane,
3-diethylamino-7- (N-methylamino) fluorane, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7- (N-methyl-N-)
Benzylamino) fluorane, 3-diethylamino-7
-(N-β-chloroethyl-N-methylamino) fluorane, 3-diethylamino-7-diethylaminofluorane, 4-benzylamino-8-diethylaminobenzo [a] fluorane, 3- [4- (4-dimethylaminoanim Rino) anilino] -7-chloro-6-methylfluorane, 8- [4- (4-dimethylaminoanilino) anilino] benzo [a] fluorane, 3- (N-ethyl-p-
Toluidino) -6-methyl-7-phenylaminofluorane, 3- (N-ethyl-p-toluidino) -6-methyl-7- (p-toluidino) fluorane, 3-diethylamino-6-methyl-7-phenyl Aminofluorane,
3-dibutylamino-6-methyl-7-phenylaminofluorane, 3-dipentylamino-6-methyl-7-
Phenylaminofluorane, 3-diethylamino-7-
(2-carbomethoxy-phenylamino) fluorane,
3- (N-ethyl-N-isoamylamino) -6-methyl-7-phenylaminofluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-phenylaminofluorane, 3- Pyrrolidino-6-methyl-
7-phenylaminofluorane, 3-piperidino-6-
Methyl-7-phenylaminofluorane, 3-diethylamino-6-methyl-7-xylidinofluorane, 3-
Diethylamino-7- (o-chlorophenylamino) fluorane, 3-dibutylamino-7- (o-chlorophenylamino) fluorane, 3- (N-ethyl-N-isoamylamino) -7- (o-chlorophenylamino) fluorane, 3- (N-methyl-N-propylamino)-
6-methyl-7-phenylaminofluorane, 3-pyrrolidino-6-methyl-7-p-butylphenylaminofluorane, 3- (N-ethyl-N-isobutylamino)
-6-Methyl-7-phenylaminofluorane, 3-pyrrolidino-6-methyl-7-pn-butylphenylaminofluorane, 3- (N-methyl-Nn-hexylamino) -6-methyl -7-Phenylaminofluorane, 3- (N-ethyl-Nn-hexylamino) -6
-Methyl-7-phenylaminofluorane, 3- (N-
Ethyl-N-cyclopentylamino) -6-methyl-7
-Phenylaminofluorane, 3- [N- (3-ethoxypropyl) -N-methylamino] -6-methyl-7-
Phenylaminofluorane, 3- [N-ethyl-N-
(3-Ethoxypropyl) amino] -6-methyl-7-
Phenylaminofluorane, 3-diethylamino-7-
[M- (trifluoromethyl) phenylamino] fluorane, 3-diethylamino-7- (o-fluorophenylamino) fluorane, 3-dibutylamino-7- (o
-Fluorophenylamino) fluorane, 3-diethylamino-6-chloro-7-phenylaminofluorane,
3- (N-ethyl-N-p-tolylamino) -7-methylfluorane, 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane, 3- (N -Cyclopentyl-N-ethylamino)-
6-methyl-7-anilinofluorane, 3- (N-ethyl-Np-tolylamino) -6-methyl-7-anilinofluorane, 2,2'-bis {4- [6 '-( Fluorane compounds such as N-cyclohexyl-N-methylamino) -3'-methylspiro [phthalide-3,9'-xanthene] -2'-ylamino] phenyl} propane,
3,6-bis (dimethylamino) fluorene-9-spiro-3 '-(6'-dimethylamino) phthalide, 3-diethylamino-6- (N-allyl-N-methylaminofluorene-9-spiro-3'-(6'-Dimethylamino) phthalide, 3,6-bis (dimethylamino) -spiro [fluorene-9,6'-6'H-chromeno (4,3
-B) indole], 3,6-bis (dimethylamino)
-3'-methyl-spiro [fluorene-9,6'-6 '
H-chromeno (4,3-b) indole], 3,6-bis (diethylamino) -3'-methyl-spiro [fluorene-9,6'-6'H-chromeno (4,3-b) indole] Such as fluorene compounds.

The present invention has an important feature in using an ionizing radiation-curable resin as an adhesive for a recording layer containing the above-mentioned specific dye precursor and color former. Specific examples of such an ionizing radiation curable resin include the following prepolymers and monomers. Examples of the prepolymer include (a) an aliphatic, alicyclic, araliphatic polyhydric alcohol having 2 to 6 valents and a poly (meth) acrylate of a polyalkylene glycol; (b) an aliphatic, an alicyclic,
Poly (meth) acrylates of polyhydric alcohols obtained by adding alkylene oxides to araliphatic or aromatic polyhydric alcohols having 2 to 6 valences; (c) Poly (meth) acryloyloxyalkyl phosphate ester; (d) Polyester poly (meth) acrylate; (e) Epoxy poly (meth) acrylate; (f) Polyurethane poly (meth) acrylate; (g) Polyamide poly (meth) acrylate; (h) Polysiloxane poly (meth) acrylate; (i ) A vinyl-based or diene-based low polymer having a (meth) acryloyloxy group at a side chain and / or a terminal; (j) The oligoester (meth) acrylate-modified product described in (a) to (i) and the like. ..

As the monomer, (a) a carboxyl group-containing monomer typified by ethylenically unsaturated mono- or polycarboxylic acid and a carboxylate group-containing alkali metal salt, ammonium salt, amine salt or the like Monomer;
(b) Amide group-containing monomer represented by vinyl lactams such as ethylenically unsaturated (meth) acrylamide or alkyl-substituted (meth) acrylamide, N-vinylpyrrolidone; (c) aliphatic or aromatic vinyl sulfone Sulfonic acid group-containing monomers represented by acids and sulfonic acid group-containing monomers such as alkali metal salts, ammonium salts, amine salts thereof; (d) Hydroxyl group-containing monomers represented by ethylenically unsaturated ethers Polymer; (e) Amino group-containing monomer such as dimethylaminoethyl (meth) acrylate-2-vinylpyridine; (f) Quaternary ammonium base-containing monomer; (g)
Alkyl ester of ethylenically unsaturated carboxylic acid; (h)
Nitrile group-containing monomers such as (meth) acrylonitrile;
(i) Styrene; (j) Esters of ethylenically unsaturated alcohols such as vinyl acetate and (meth) allyl acetate; (k) Mono (meth) acrylates of alkylene oxide addition polymers of compounds containing active hydrogen; l) Containing ester group represented by diester of polybasic acid and unsaturated alcohol 2
Functional monomer; (m) Bifunctional monomer consisting of diester of alkylene oxide addition polymer of compound containing active hydrogen and (meth) acrylic acid; (n) Bis such as N, N-methylenebisacrylamide Acrylamide; (o) difunctional monomers such as divinylbenzene, divinylethylene glycol, divinylsulfone, divinyl ether, divinyl ketone; (p) ester group-containing polyfunctionality represented by polyester of polycarboxylic acid and unsaturated alcohol Monomer;
(q) a polyfunctional monomer composed of a polyester of an alkylene oxide addition polymer of a compound containing active hydrogen and (meth) acrylic acid; (r) a polyfunctional unsaturated monomer such as trivinylbenzene Can be mentioned. The ionizing radiation curable resins as described above may be used in combination of two or more kinds.

The amount of the ionizing radiation-curable resin used is not particularly limited, but is adjusted within the range of 1 to 90% by weight, preferably 5 to 60% by weight, based on the total solid content of the recording layer coating liquid. Is desirable.

In the present invention, various heat fusible substances can be used as a recording sensitivity improving agent in order to obtain suitability for high speed recording. Examples of such a heat-fusible substance include caproic acid amide, capric acid amide, palmitic acid amide, stearic acid amide, oleic acid amide, erucic acid amide, linoleic acid amide, linolenic acid amide, N
-Methylstearic acid amide, stearic acid anilide,
N-methyloleic acid amide, benzanilide, linoleic acid anilide, N-ethylcapric acid amide, N-butyllauric acid amide, N-octadecylacetamide,
N-oleinacetamide, N-oleylbenzamide, N-stearylcyclohexylamide, polyethylene glycol, 1-benzyloxynaphthalene, 2-benzyloxynaphthalene, 1-hydroxynaphthoic acid phenyl ester, 1,2-diphenoxyethane, 1,4
-Diphenoxybutane, 1,2-bis (3-methylphenoxy) ethane, 1,2-bis (4-methoxyphenoxy) ethane, 1-phenoxy-2- (4-chlorophenoxy) ethane, 1-phenoxy-2 -(4-Methoxyphenoxy) ethane, 1- (2-methylphenoxy) -2
-(4-Methoxyphenoxy) ethane, terephthalic acid dibenzyl ester, oxalic acid dibenzyl ester, oxalic acid di-p-methylbenzyl ester, p-benzyloxybenzoic acid benzyl ester, p-benzylbiphenyl, 1,5-bis (P-Methoxyphenoxy) -3-oxa-pentane, 1,4-bis (2-vinyloxyethoxy) benzene, p-biphenyl-p-tolyl-ether, benzyl-p-methylthiophenyl ether, 4-
Chlorobenzyl-4-ethoxyphenyl-ether,
Examples include compounds such as 1,2-bis (3,4-dimethylphenyl) ethane. The amount of the heat-fusible substance used is not particularly limited, but it is generally desirable to adjust the amount within the range of 0.1 to 50 parts by weight relative to 1 part by weight of the dye precursor.

Further, various auxiliaries can be added to the recording layer, and examples thereof include a dispersant, an ultraviolet absorber such as a triazole type, an antifoaming agent, a fluorescent dye and a coloring dye. In addition, stearic acid ester wax, polyethylene wax, carnauba wax, microcrystalline wax, carboxy-modified paraffin wax, zinc stearate, calcium stearate, etc. are added to prevent the thermal recording material from sticking due to contact with recording equipment or recording head. You can also do it. In addition, calcium carbonate, barium carbonate, zinc carbonate, zinc oxide, aluminum oxide, titanium dioxide, silicon dioxide, aluminum hydroxide, barium sulphate, zinc sulphate, talc, kaolin, clay in order to improve the adhesion of dust to the recording head. , Inorganic pigments such as calcined clay, colloidal silica, etc., pigments obtained by surface-treating these inorganic pigments with organic acids, styrene microballs, nylon powder, polyethylene powder, urea / formalin resin powder, cellulose acetate powder, polymethylmethacrylate powder, fluorine Organic powders such as resin powders, epoxy resin powders, benzoguanamine resin powders, raw starch granules, and even non-ionizing radiation curable resins can be added. Examples of the non-ionizing radiation curable resin include acrylic resin, silicon resin, alkyd resin, fluororesin, butyral resin and the like.

The heat-sensitive recording material of the present invention is prepared by ionizing and releasing as described above.
In prepolymer and / or monomer of radiation curable resin
Specific dye precursors and colorants, and as needed
Disperse together or separately with the heat-fusible substance used together
The coating liquid prepared by
Suitable support such as synthetic paper, non-woven sheet and molded products
After coating or printing on top, irradiate with ionizing radiation
It is prepared by curing the coating liquid. In addition, coating equipment and printing
The device is not particularly limited, and can be appropriately selected from known devices.
It can be selected and used. Also, the amount of coating liquid applied to the support
Is also not particularly limited, and is usually 2 to 12 by dry weight.
g / m²Degree, preferably 3 to 10 g / m ²Range of degree
Is adjusted by.

In the present invention, the ionizing radiation-curable resin after coating or printing is cured by irradiation with ionizing radiation. Examples of the ionizing radiation include electron beams, ultraviolet rays and α
Ray, β ray, γ ray, X ray and the like. α rays, β rays, γ
Since X-rays and X-rays are accompanied by problems such as danger to the human body, electron beams and ultraviolet rays, which are easy to handle and widely used industrially, are preferably used. When an electron beam is used, the amount of the electron beam to be irradiated is preferably adjusted within the range of 0.1 to 15 Mrad, more preferably 0.5 to 10 Mrad. Incidentally, if it is less than 0.1 M rad, the curing of the resin becomes insufficient, and if it exceeds 15 M rad, the paper strength is greatly reduced. As an electron beam irradiation method, a scanning method, a curtain beam method, a broad beam method, or the like can be appropriately adopted, and an acceleration voltage at the time of electron beam irradiation is 10
About 0 to 300 kV is suitable. Incidentally, electron beam irradiation has the advantages that it has higher productivity than ultraviolet irradiation and there is no problem of odor or coloring due to addition of a sensitizer.

When ultraviolet rays are used, it is necessary to blend a sensitizer in the ionizing radiation curable resin. For example, thioxanthone, benzoin, benzoin alkyl ether xanthone, dimethylxanthone, benzophenone, anthracene, 2,2-diene. Ethoxyacetophenone, benzyl dimethyl ketal, benzyl diphenyl disulfide, anthraquinone, 1-chloroanthraquinone, 2-
One or more sensitizers such as ethylanthraquinone, 2-tert-butylanthraquinone, N, N'-tetraethyl-4,4'-diaminobenzophenone, and 1,1-dichloroacetophenone are appropriately mixed. The amount of the sensitizer used is 0.1 to 10% by weight, preferably 0.5 to 5% by weight, in the ionizing radiation curable resin. Further, in order to accelerate curing in addition to such a sensitizer, for example, triethanolamine, 2-dimethylaminoethanol, dimethylaminobenzoic acid, isoamyl dimethylaminobenzoate, dioctylaminobenzoic acid,
Tertiary amines such as lauryl dimethylaminobenzoate can also be blended in the ionizing radiation curable resin in an amount of about 0.05 to 3% by weight.

As a light source for irradiating ultraviolet rays, 1 to 50 ultraviolet lamps (for example, low pressure, medium pressure and high pressure mercury lamps having an operating pressure of several mmHg to about 10 atmospheres), xenon lamps, tungsten lamps, etc. are used. 5,000
Ultraviolet rays having an intensity of about 8000 μW / cm ² are preferably irradiated.

In the present invention, a protective layer made of an ionizing radiation curable resin or the like may be further formed on the recording layer, if necessary. It is also possible to add pigments and auxiliaries to the protective layer. Further, it is of course possible to provide an antistatic layer or a protective layer on the back surface of the support, or to provide an undercoat layer on the support, and further to apply a pressure-sensitive adhesive to the back surface of the support for various types of heat-sensitive recording material manufacturing fields. The publicly known technology can be added.

[0034]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Unless otherwise specified, "part" and "%" in the examples represent "part by weight" and "% by weight", respectively.

Example 1 Preparation of Solution A 3,6-di (tert-butoxycarboxy) fluorane 1
5 parts, 1,2-bis (3-methylphenoxy) ethane 4
0 parts, oligoester acrylate (trade name: Aronix M-8030, manufactured by Toagosei Kagaku) 35 parts, and monofunctional acrylate (trade name: Aronix M-10
35 parts (manufactured by Toagosei Kagaku Co., Ltd.) were thoroughly stirred and mixed. Preparation of Solution B 15 parts of zinc salt of 3,5-di (α-methylbenzyl) salicylic acid, 35 parts of oligoester acrylate (trade name: Aronix M-8030, manufactured by Toagosei Kagaku), and monofunctional acrylate (trade name: Aronix M-10
35 parts (manufactured by Toagosei Kagaku Co., Ltd.) were thoroughly stirred and mixed.

Formation of Recording Layer The coating liquid obtained by thoroughly mixing the above liquids A and B at a ratio of 1: 3 was applied to a base paper having a weight of 50 g / m ² and a dry weight of 6.0 g / m ^2.
So as to be 3 times, followed by 3 with an electro-curtain type electron beam irradiation device (CB-150 type, manufactured by ESI).
The resin component was cured by treatment with an irradiation dose of Mrad to obtain a thermosensitive recording medium.

Examples 2 to 15 14 kinds of compounds were prepared in the same manner as in Example 1 except that the following compounds were used in place of 3,6-di (tert-butoxycarboxy) fluorane in the preparation of solution A in Example 1. A thermosensitive recording medium was obtained. -Example 2: 3- (tert-butoxycarboxy) -6-
Methoxyfluorane-Example 3: 3- (tert-butoxycarboxy) -6-
Dimethylaminofluorane Example 4: 3,6-di (tert-butoxycarboxy)
-2,4,5,7-Tetrabromofluorane-Example 5: 3,6-di (tert-butoxycarboxy)
-1,8-Dimethyl-3 ', 4', 5 ', 6'-tetrachlorofluorane-Example 6: 3,6-di (1,1-dimethylpropoxycarboxy) fluorane-Example 7: O, O'-di (tert-butoxycarbonyl) phenol sulfophthalein Example 8: O, O'-di (tert-butoxycarbonyl) -2,2'-dimethyl-3,3'-dibromo-5,5
5'-Diisopropylphenolsulfophthalein-Example 9: O, O'-di (1,1-dimethylbutoxycarbonyl) phenolsulfophthalein-Example 10: O, O'-di (tert-butoxycarbonyl) indigo White-Example 11: O, O'-di (tert-butoxycarbonyl) -6,6'-dibromoindigo white-Example 12: O, O'-di (tert-butoxycarbonyl) -N, N'- Dimethylindigo white-Example 13: O, O'-di (tert-butoxycarbonyl) thioindigo white-Example 14: O, O'-di (tert-butoxycarbonyl) -5,5'-dichloro-7, 7'-Dimethylthioindigo white Example 15: O, O'-di (1,1-dimethylpropoxycarbonyl) indigo white

Example 16 Preparation of C liquid 15 parts of zinc salt of 3,5-di (α-methylbenzyl) salicylic acid, 35 parts of oligoester acrylate (trade name: Aronix M-8030, manufactured by Toagosei Kagaku), monofunctional 35 parts of acrylate (trade name: Aronix M-101, manufactured by Toagosei Kagaku), 5 parts of zinc stearate, and 5 parts of calcium carbonate were sufficiently stirred and mixed. Formation of Recording Layer A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the above-mentioned liquid C was used instead of the liquid B.

Examples 17 to 21 Oligoester acrylates (trade name: Aronix M- used in the preparation of solutions A and B of Example 1)
8030, Toa Gosei Kagaku Co., Ltd.) 35 parts, and monofunctional acrylate (trade name: Aronix M-101, Toa Gosei Kagaku Co., Ltd.) 35 parts were used in the same manner as in Example 1 except that the following compounds were used. As a result, 5 kinds of thermal recording materials were obtained. -Example 17: 2-hydroxypropyl acrylate 70
Parts-Example 18: 2-Ethylhexyl acrylate 70 parts-Example 19: Urethane acrylate (trade name: Aronix M-1100, manufactured by Toagosei Co., Ltd.) 70 parts-Example 20: Epoxy acrylate 70 parts-Example 21: Penta Erythritol triacrylate 7
Copy 0

Examples 22 to 23 In the same manner as in Example 1, except that the following compounds were used in place of the zinc salt of 3,5-di (α-methylbenzyl) salicylic acid in the preparation of solution A in Example 1. Two types of thermal recording materials were obtained. Example 23: 4,4'-isopropylidene diphenol Example 24: 3,5-di (α-methylbenzyl) salicylic acid

Example 24 As a support, 100 μm was used instead of 50 g / m ² base paper.
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the polyethylene film of m was used.

Comparative Examples 1 to 3 Three kinds of compounds were prepared in the same manner as in Example 1 except that the following compounds were used in place of 3,6-di (tert-butoxycarboxy) fluorane in the preparation of solution A in Example 1. A thermosensitive recording medium was obtained. -Comparative example 1: 3,6-dimethoxyfluorane-Comparative example 2: 3-dibutylamino-6-methyl-7-anilinofluorane-Comparative example 3: Crystal violet lactone

Comparative Example 4 Preparation of Solution D 3,6-di (tert-butoxycarboxy) fluorane 1
5 parts, 1,2-bis (3-methylphenoxy) ethane 4
A composition consisting of 0 part, 25 parts of a 25% aqueous solution of methyl cellulose, and 40 parts of water was pulverized with a sand mill for 2 hours. Preparation of Solution E A composition consisting of 15 parts of a zinc salt of 3,5-di (α-methylbenzyl) salicylic acid, 25 parts of a 25% aqueous solution of methylcellulose, and 40 parts of water was pulverized in a sand mill for 2 hours. Formation of Recording Layer In the formation of the recording layer of Example 1, a thermosensitive recording medium was prepared in the same manner as in Example 1 except that the above-mentioned liquid D was used instead of the liquid A and the above liquid E was used instead of the liquid B. Obtained.

Comparative Example 5 Preparation of Solution F 3,6-di (tert-butoxycarboxy) fluorane 1
5 parts, 1,2-bis (3-methylphenoxy) ethane 4
A composition consisting of 0 part, 25 parts of a 25% aqueous solution of methyl cellulose, and 40 parts of water was pulverized with a sand mill for 2 hours. Preparation of Solution G A composition consisting of 15 parts of 4,4′-isopropylidenediphenol, 25 parts of a 25% aqueous solution of methylcellulose, and 40 parts of water was pulverized with a sand mill for 2 hours. Formation of Recording Layer In the formation of the recording layer of Example 1, a thermosensitive recording medium was obtained in the same manner as in Example 1 except that the above-mentioned liquid F was used instead of the liquid A and the above-mentioned liquid G was used instead of the liquid B. ..

The whiteness of the recording layer of each thermosensitive recording medium thus obtained was measured with a Hunter whiteness meter, and the results are shown in Table 1.
Described in. Next, each thermosensitive recording medium was heated to 150 ° C. to develop color, and the degree of color development was visually evaluated, and the results are shown in Table 1.

Further, in order to evaluate the chemical resistance, a vinyl chloride film is placed on the color-developing surface of the above recording material and the temperature is kept at 40 ° C. for 2 hours.
When left for 00 hours (plasticizer resistance) and when ethanol was applied to the color development surface (ethanol resistance), the degree of fog on the white paper part and the fading of the recorded image were evaluated, and the results are shown in Table 1. Indicated. The evaluation criteria are as follows. “Evaluation Criteria” ⊚: Excellent. ◯: Excellent. Δ: Slightly inferior X: Inferior

Further, in order to evaluate the water resistance, water was applied to the color-developing surface and the surface was rubbed by hand to observe the elution state of the coating layer with respect to water. The evaluation criteria are as follows. "Evaluation criteria" A: No elution occurs. ◯: It elutes slightly, but there is no problem in practical use. X: Elution is considerably remarkable.

[0048]

[Table 1]

[0049]

As is clear from the results shown in Table 1, the thermosensitive recording medium of the present invention has high whiteness, is excellent in chemical resistance, plasticizer resistance and water resistance, and is also excellent in color development. It was a body.

Claims (2)

[Claims] 1. [Chemical formula 1], [Chemical formula 2] and [Chemical formula 1] on a support
3] at least one of the dye precursors represented by
Coloring agent capable of coloring the precursor and ionizing radiation curable resin
After coating the coating liquid for the recording layer containing
A thermosensitive recording material characterized by being cured by radiation. [Chemical 1][Wherein Ra is C_Four~ C₁₂Represents a tertiary alkyl group of R
₁~ R₁₁Are hydrogen atom, halogen atom, C₁~ C
₁₂Alkyl group of C₁~ C₁₂Alkoxyl group, hydroxy
Group, nitro group, -N (R₁₂) (R₁₃), -O (CO) OR
₁₄, Or -O (CO) R₁₅Indicates. However, R₁₂, R₁₃Is
Hydrogen atom; C₁~ C₁₂Alkyl group of C_Four~ C
₁₂Cycloalkyl group; halogen atom, C₁~ C₆A
Rukiru group, C ₁~ C₆Substituted with the alkoxyl group of
Good aralkyl group; halogen atom, C₁~ C₆The al
Kill group, C₁~ C₆May be substituted with an alkoxyl group
Shows an aryl group, R₁₂And R₁₃Is an adjacent nitrogen atom
Pyrrolidino group, piperidino group or hexamethylene
An imino group may be formed. Also, R₁₄Is C₁~ C₁₂of
Alkyl group; benzyl group; halogen atom, C₁~ C₆of
Alkyl group, C₁~ C₆Substituted with an alkoxyl group of
Also represents an aryl group, R₁₅Is C₁~ C₁₂The alkyl
Group; benzyl group; halogen atom, C₁~ C₆The alkyl
Base, C₁~ C₆Which may be substituted with an alkoxyl group of
Reel group; -N (R₁₆) (R₁₇) Is shown. Incidentally, R₁₆, R₁₇
Are hydrogen atoms; C₁~ C₁₂Alkyl group of C_Four~
C₁₂Cycloalkyl group; halogen atom, C₁~ C₆of
Alkyl group, C₁~ C₆Substituted with an alkoxyl group of
Good aralkyl group; halogen atom, C₁~ C₆A
Rukiru group, C₁~ C₆Substituted with the alkoxyl group of
Shows a good aryl group, but R ₁₆And R₁₇Is the adjacent nitrogen source
With pyrrolidino group, piperidino group or hexamethy
It may also form a renimino group. ] [Chemical 2][Wherein Rb is C_Four~ C₁₂Represents a tertiary alkyl group of R
₁₈~ R₃₀Are hydrogen atom, halogen atom, C₁~ C
₁₂Alkyl group of C₁~ C₁₂Alkoxyl group, hydroxy
Group, -O (CO) OR₃₁, Or -O (CO) R₃₂Shows
You However, R₃₁, R₃₂Are each C₁~ C₁₂The alkyl
Group; benzyl group; halogen atom, C₁~ C₆The alkyl
Base, C₁~ C₆Which may be substituted with an alkoxyl group of
The reel group is shown. ] [Chemical 3][Wherein Rc and Rd are each C_Four~ C₁₂The third-class Archi
Represents a radical. X and Y are> NR₄₁, Or -S-
As shown, X and Y may be combined in the form> NANN <
Yes. Where R₄₁Is a hydrogen atom, C₁~ C_TenThe alkyl
Group, -COR₄₂Or -COOR₄₃And A is C₁~ C
_TenIs a saturated or unsaturated alkylene group. Also, R
₄₂, R₄₃Are each C₁~ C₁₂Alkyl group of benzyl
Group; halogen atom, C₁~ C₆Alkyl group of C₁~ C
₆Represents an aryl group which may be substituted with an alkoxyl group of
You Also, R₃₃~ R₄₀Are hydrogen atom and halogen atom, respectively
Child, C₁~ C_TenAlkyl group of C₁~ C_TenThe alkoxy
Group, nitro group, -N (R₄₄) (R ₄₅), Or -SR₄₆To
Show. Incidentally, R₃₃And R₃₄, R₃₄And R₃₅, R₃₅And R₃₆, R₃₇
And R₃₈, R₃₈And R₃₉, R₃₉And R₄₀Are benzene rings
May be formed. Where R₄₄, R₄₅Are each hydrogen
Atom; C₁~ C₁₂Alkyl group of C_Four~ C₁₂Cycloa
Rualkyl group; halogen atom, C₁~ C₆Alkyl group of C
₁~ C₆Which may be substituted with an alkoxyl group of
Kill group; halogen atom, C₁~ C₆Alkyl group of C₁
~ C₆Aryl group which may be substituted with an alkoxyl group of
, But R ₄₄And R₄₅Together with the adjacent nitrogen atom
A dino group, piperidino group or hexamethyleneimino group
You may form. Also, R₄₆Is C₁~ C_TenAlkyl group of
Indicates. ] 2. A thermosensitive recording medium according to claim 1, wherein Ra, Rb, Rc and Rd in the general formulas [Chemical formula 1], [Chemical formula 2] and [Chemical formula 3] are tert-butyl groups.