JP2002326463A - Heat-sensitive recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-sensitive recording medium which has excellent preservability of a recording image without decreasing whiteness of a recording layer even when the layer is preserved under a high temperature condition and which has small discoloring and fading of the image and a skin part due to an NOX or an SOX contained in an exhaust gas. SOLUTION: The heat-sensitive recording medium comprises a heat-sensitive recording layer which contains a colorless or pale basic dye, and a colorant which colors in contact with the dye in such a manner that as the colorant, both 3-(p-hydroxyphenyl)-1,1,3-trimethyl-5-indanol and 1,1-spirobis-(3,3-dimethyl-6- hydroxyindane) are adopted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermosensitive recording medium,
Even when stored for a long time, the whiteness of the background does not decrease and the storage stability of the recorded image is excellent, and even if the recorded image and the background are exposed to NO _X or SO _X contained in the exhaust gas, The present invention relates to a thermosensitive recording medium with less fading.

[0002]

2. Description of the Related Art Conventionally, a heat-sensitive recording material comprises a colorless or light-colored basic dye and an organic colorant such as a phenolic compound.
After each dispersed in fine particles, the two are mixed, and a coating liquid obtained by adding a binder, a filler, a color former, a lubricant and other auxiliaries is used as a recording layer for paper, synthetic paper, plastic film, etc. Thermal recording media coated on a support and melted by heating with a hot pen, a thermal head, a hot stamp, or the like, so as to obtain a recorded image by contacting both coloring materials are well known. Recently, these thermal recording systems have become faster and have been applied to a wide range of fields such as facsimile machines, automatic ticket vending machines, barcode labels, recorders for measurement, and toll road tickets.
As the performance has been improved, the required quality of the thermal recording medium has also become higher. For example, it is required that high-density and clear recording images can be obtained even with a small amount of thermal energy without lowering the whiteness of the recording medium before recording as the recording speed increases. For example, it may be left at a temperature of about 40 ° C. for a long time. In this case, the color reaction may proceed to cause color fog.

[0003] Further, a thermosensitive recording material using a basic dye or an acidic substance as a coloring agent, which is generally used, is used in automobiles and petroleum stoves.
When exposed to an active gas such as NO _X or SO _X contained in exhaust gas such as air bubbles, there arises a problem that a recorded image and a background portion discolor and fade, and improvement thereof has been desired.

As a conventional example of a heat-sensitive recording material, for example, JP-A-57-41991 and JP-A-60-260386 disclose a heat-sensitive recording material using an indanol derivative as a coloring agent. However, when an indanol derivative is used as a colorant, a thermosensitive recording medium having a high whiteness can be obtained.However, a recorded image and a background portion are easily discolored and discolored by exhaust gas. Again, further improvement is required.

[0005]

[0008] The present invention is excellent in storage stability of recording image without be stored under high-temperature conditions would decrease the whiteness of the recording layer, NO _X and S contained in the exhaust gas
And to provide a less heat-sensitive recording material of discoloration of the recorded image and background portions by O _X.

[0006]

Means for Solving the Problems The present inventors have developed a thermosensitive recording medium having a colorless or light-colored basic dye and a coloring agent provided on a support, as the coloring agent. 3- (p-hydroxyphenyl) -1,1,3-trimethyl-5-indanol and 1,1-spirobis (3,3
-Dimethyl-6-hydroxyindane) was used to solve the above-mentioned problem.

The 3- (p-hydroxyphenyl) -1,1,3-trimethyl-5-indanol and 1,1-spirobis (3,3-dimethyl-6-hydroxyindane) used in the present invention are prepared by a known method. Can be manufactured. For example, a chain dimer of p-isopropenylphenol, 2,4-di (p-hydroxyphenyl) -4-
A method of subjecting a mixture of methyl-pentene-1 and pentene-2 to a cyclization reaction in the presence of an acid catalyst (JP-A-56-19)
333, JP-A-4-26644), a method of decomposing and cyclizing bisphenol A with an acid catalyst (JP-A-5-264)
-294879, U.S. Pat.
No. 4, etc.). Also, 1,1-spirobis (3,3-dimethyl-6-hydroxyindane)
Is the aforementioned 3- (p-hydroxyphenyl) -1,1,3
-Trimethyl-5-indanol and bisphenol A or p-isopropenylphenol in the presence of an acid catalyst (US Pat. No. 470).
No. 1566).

In the heat-sensitive recording material of the present invention, 3- (p-
(Hydroxyphenyl) -1,1,3-trimethyl-5-
The combined ratio of indanol and 1,1-spirobis (3,3-dimethyl-6-hydroxyindane) is preferably about 100: 0.1 to 10, more preferably about 100: 0.1 to 7 by weight. If the amount of the latter is too small, there is no effect, and if the amount is too large, a new defect such as a decrease in the whiteness of the background portion occurs. The ratio is 100: If it is 0.2 to 5, decrease in whiteness less, particularly preferably exhibits a very excellent effect against discoloration which body in the NO _X in the recorded image.

With respect to the method for preparing the colorant composition,
3- (p-hydroxyphenyl) -1,1,3-trimethyl-5-indanol and 1,1-spirobis (3,3
-Dimethyl-6-hydroxyindane) to obtain a desired ratio. 3 more
When producing-(p-hydroxyphenyl) -1,1,3-trimethyl-5-indanol, depending on the reaction conditions, 1,1-spirobis (3,3-dimethyl-6-hydroxyindane) is produced by-product. (For example, U.S. Pat. No. 3,271,463), the two compounds may be prepared so as to have a desired ratio, or may be further purified and adjusted to have a desired ratio.

[0010] The amount of the colorant used is not particularly limited, but is generally adjusted in the range of 50 to 1000 parts by weight, particularly about 150 to 700 parts by weight, per 100 parts by weight of the basic dye. desirable.

In the present invention, 3- (p-hydroxyphenyl) -1,1,3-trimethyl-5-indanol and 1,1-spirobis (3,3-dimethyl-6) are used as color formers.
- hydroxy indane) By combining the storage stability of the recorded image and sufficient whiteness, but in which heat-sensitive recording material is obtained having a pair NO _X of the recorded image and background portions, further the following general formula (1) The combined use of the phenol compounds represented by the formulas [7] to [7] can further improve the storage stability of the recorded image.

[0012]

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[0013]

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[0014]

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[0015]

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[0016]

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[0017]

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[0018]

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As the compound represented by the general formula [1],
p-Hydroxybenzoic acid benzyl ester, p-hydroxybenzoic acid-p-methylbenzyl ester, and compounds represented by the general formula [2] include 4,4′-thiobis (2-methylphenol) and 4,4′- Thiobis (2
3-dimethylphenol), the compound represented by the general formula [3] includes 2,2′-thiobis (4-t-octylphenol), and the compound represented by the general formula [4] includes 4,4 ′ -Dihydroxy-diphenyl sulfone,
2,4'-dihydroxy-diphenylsulfone, 4-hydroxy-4'-i-propoxydiphenylsulfone, 3,3'-diallyl-4,4'-dihydroxy-diphenylsulfone, represented by the general formula [5] As the compound, 2,2-bis (4-hydroxyphenyl) -4-
Methylpentane, 2,2-bis (4-hydroxyphenyl) -n-heptane, 1,1-bis (4-hydroxyphenyl) acetic acid butyl ester, n-butyl-4,4-bis (4-hydroxyphenyl) Pentanoate, 1,1,
1-tris (p-hydroxyphenyl) ethane, 4,
4 '-{1- [4- (2- (4-hydroxyphenyl)
-2-propyl] phenyl] ethylidene-bisphenol, the compound represented by the general formula [6] includes 2,4-
Bis (4-hydroxyphenyl) -4-methylpentane, 4-methyl-2,4-bis (4-hydroxyphenyl) -pent-1-ene, 3,4-bis (4-hydroxyphenyl) hexane, general formula As the compound represented by [7], 2 ′, 4-dihydroxybenzophenone,
4,4'-dihydroxybenzophenone and the like, but are not limited thereto.

In such a color former composition, 3- (p-
(Hydroxyphenyl) -1,1,3-trimethyl-5-
If the amount of the compounds of the general formulas [1] to [7] is too small, the effect is not obtained, and if the amount is too large, the recording paper is not used for the mixture of indanol and 1,1-spirobis (3,3-dimethyl-6-hydroxyindane). To produce new defects such as lowering the whiteness of 3- (p-hydroxyphenyl) -1,1,3-trimethyl-5-indanol and 1,1-spirobis (3,3-dimethyl-6- 10 to 10 parts by weight of at least one compound of the general formulas [1] to [7] with respect to 100 parts by weight of the mixture of (hydroxyindane).
0 parts by weight, preferably 10 to 80 parts by weight, more preferably 20 to 70 parts by weight.

In the present invention, the general formulas [8] to [1]
When at least one compound selected from the group consisting of the hindered phenol compound 2) and / or the hindered phenol phosphate compound represented by the general formula [13] is contained in the heat-sensitive recording layer as a storage stability improver, the present invention provides The preservation of the recorded image can be further improved without impairing the desired effect.

[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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As the compound represented by the general formula [8],
4,4′-thiobis (6-t-butyl-m-cresol), 4,4′-thiobis (6-t-butyl-o-cresol), 4,4′-thiobis (2,6-di-t -Butylphenol), general formula

Examples of the compound represented by [9] include 2,2′-methylenebis (4-methyl-6-t-butylphenol), 2,2′-methylenebis (4-ethyl-6-t-butylphenol), 2,2 '-Ethylidenebis (4,6-di-t-butylphenol), 2-t
-Butyl-6- (3-t-butyl-2-hydroxy-5
-Methylbenzyl) -4-methylphenyl acrylate, 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate, general formula [ 10] include 4,4′-butylidene (6-t-butyl-
m-clay sol), 1,1,3-tris (2-methyl-
4-hydroxy-5-cyclohexylphenyl) butane, a compound represented by the general formula [11],
3,5-tris (4-t-butyl-3-hydroxy-
2,6-dimethylbenzyl) isocyanuric acid, 1,3
5-Tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanuric acid, a compound represented by the general formula [12], includes 1,3,5-tris (3,5-di-t
-Butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, and the compound represented by the general formula [13] include 2,2′-methylenebis (4,6-di-t-butyl) phosphate and Metal salts of these potassium, sodium, zinc, calcium, magnesium, aluminum and the like can be mentioned.

The amount of the preservability improver is not particularly limited, but is generally 10 to 500 parts by weight, preferably 30 to 35 parts by weight, per 100 parts by weight of the specific basic dye.
It is preferable to adjust within the range of 0 parts by weight.

The basic dye used in the present invention is a dye applicable to this type of heat-sensitive recording material, specifically, 3-di-n.
-Butylamino-6-methyl-7-anilinofluoran, 3-di-n-pentylamino-6-methyl-7-anilino-fluoran, 3-N- (i-pentyl) ethylamino-6-methyl-7 -Anilinofluoran, 3-N
-Ethyl-N-isopropylamino-6-methyl-7-
Anilinofluoran, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluoran, 3
-N-methyl-N-isobutylamino-6-methyl-7
-Anilinofluoran, 3-N-ethyl-N-p-tolylamino-6-methyl-7-anilinofluoran, 3-
Pyrrolidino-6-methyl-7-anilinofluoran, 3
-Piperidino-6-methyl-7-anilinofluoran,
3-N-ethyl-N-tetrahydrofurfurylamino-
6-methyl-7-anilinofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-N-
Ethyl-N- (2-ethoxypropyl) amino-6-methyl-7-anilinofluoran, 3-diethylamino-
7- (o-chloroanilino) fluoran, 3-di-n-
Butylamino-7- (o-chloroanilino) fluoran, 3-diethylamino-7- (o-trifluoromethylanilino) fluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-6-methyl-7
-Chlorofluorane, 3-cyclohexylamino-6-
Chlorofluorane, 3-N-ethyl-Np-tolylamino-7-methylfluoran, 3-diethylamino-
7,8-benzofluoran, 3-diethylamino-7-
t-butylfluoran, 3-N-ethyl-N-p-tolylamino-7-N-methyl-N-phenylaminofluoran, 3-diethylamino-7-dibenzylaminofluoran, 2-methyl-6-p -(P-dimethylaminophenyl) aminoanilinofluoran, 2-chloro-3-
Fluoran compounds such as methyl-6-p- (p-dimethylaminophenyl) aminoanilinofluoran;
Bis (p-dimethylaminophenyl) phthalide, 3,3
-Bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (p-dimethylaminophenyl)
3- (1,2-dimethylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2
-Methylindol-3-yl) phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindole-3- Yl) -6-dimethylaminophthalide, 3,3-bis (9-ethylcarbazol-3-yl) -6-dimethylaminophthalide, 3,3-bis (2
-Finynlindol-3-yl) -6-dimethylaminophthalide, 3-p-dimethylaminophenyl-3-
Triarylmethanephthalide compounds such as (1-methylpyrrol-3-yl) -6-dimethylaminophthalide;
3,6-bis (dimethylamino) fluorene-9-spiro-3 ′-(6′-dimethylamino) phthalide, 3,6
-Bis (diethylamino) fluorene-9-spiro-
Fluorenephthalide compounds such as 3 '-(6'-dimethylamino) phthalide, 3,3-bis [2- (p-dimethylaminophenyl) -2- (p-methoxyphenyl) ethenyl] -4,5,6 , 7-tetrachlorophthalide, 3,
3-bis [2- (p-dimethylaminophenyl) -2-
(P-methoxyphenyl) ethenyl] -4,5,6,7
Divinylphthalide such as tetrabromophthalide, 3,3-bis [2- (p-pyrrolidinophenyl) -2- (p-methoxyphenyl) ethenyl] -4,5,6,7-tetrachlorophthalide Compounds, phenothiazine compounds such as benzoyl leucomethylene blue, auramine compounds such as 4,4'-bisdimethylaminobenzohydryl benzyl ether, No-chlorophenyl-leuco auramine, 3-methyl-spirodinaphthopyran, 3-ethyl −
Examples include spiropyran compounds such as spirodinaphthopyran, and lactam compounds such as rhodamine B-anilinolactam and rhodamine (p-nitroanilino) lactam.

These dyes may be used alone or as a mixture of two or more. Among them, 3-di-n-butylamino-6-methyl-7-anilinofluoran and 3-di-n
-Pentylamino-6-methyl-7-anilino-fluoran, 3-N- (i-pentyl) ethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-
Since 6-methyl-7-anilinofluoran has a color tone of black suitable for a recording medium, has little stain on the background, and has good color developability, the use of these dyes in the present invention is preferred. Is particularly preferred. In the present invention, a heat-fusible substance (melting point of 70 to 1) may be added to the heat-sensitive recording layer as a coloring property improving agent.
(50 ° C., preferably 80 to 130 ° C.).

Examples of the color developing agent include oxalic acid-dibenzyl ester, oxalic acid-di (p-methylbenzyl) ester, 2-benzyloxynaphthalene, m-terphenyl, p-benzylbiphenyl, 4- (p-methyl) Phenoxy) biphenyl, 1,2-bis (phenoxy) ethane, 1,2-bis (3-methylphenoxy) ethane, stearamide, methylenebisamide stearate,
Stearic acid ethylene bisamide, stearic acid methylolamide, oleic acid amide, palmitic acid amide,
Fatty acid amides such as coconut fatty acid amides, dibenzyl terephthalate, 1-hydroxy-2-naphthoic acid phenyl ester and the like can be mentioned.

The type of the color developing agent is not particularly limited, but among them, oxalic acid-dibenzyl ester,
Oxalic acid-di (p-methylbenzyl) ester, 2-benzyloxynaphthalene, m-terphenyl, p-benzylbiphenyl, 4- (p-methylphenoxy) biphenyl, 1,2-bis (phenoxy) ethane, Since 2,2-bis (3-methylphenoxy) ethane is particularly suitable for high-speed recording when combined with the color former of the present invention, it is preferable to use at least one of these. The amount of the color former is not particularly limited, but is generally 10 to 700 parts by weight, preferably 20 to 50 parts by weight, per 100 parts by weight of the basic dye.
It is preferable to adjust the amount within a range of 0 parts by weight.

The coating liquid containing these is generally mixed with water as a dispersing medium, and a dye, a pigment, a stirrer or a pulverizer such as a ball mill, attritor, vertical or horizontal sand mill, or colloid mill is used.
It is prepared by, for example, dispersing together a color former, a color improver, a preservability improver to be used in combination as necessary, or separately. In such a coating solution, usually as a binder starches, hydroxyethyl cellulose, methyl cellulose,
Carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl alcohol, carboxy group-modified polyvinyl alcohol, various modified polyvinyl alcohols such as silicon-modified polyvinyl alcohol, styrene / maleic anhydride copolymer salt, ethylene / acrylic acid copolymer salt, Styrene / acrylic acid copolymer salt, styrene / butadiene copolymer emulsion, etc. are 2 to 40
% By weight, preferably about 5 to 25% by weight. Of course, two or more of these binders can be used in combination.

Further, various auxiliaries can be added to the coating solution. Examples of these auxiliaries include dispersants such as dioctyl sulfosuccinate sodium salt and fatty acid metal salt, benzophenone-based, cyano-based, and the like. Examples include acrylate-based and hydroxybenzoate-based ultraviolet absorbers, other antifoaming agents, fluorescent dyes, direct-color dyes, and the like.

Also, a stearic acid ester wax, a polyethylene wax,
Dispersions and emulsions of carnauba wax, microcrystalline wax, modified carboxy paraffin wax, zinc stearate, calcium stearate and the like can also be added.

Further, inorganic pigments such as kaolin, clay, talc, calcium carbonate, magnesium carbonate, calcined clay, titanium oxide, diatomaceous earth, finely divided anhydrous silica, activated clay, and styrene microparticles are used to improve the adhesion of scum to the recording head. Organic pigments such as balls, nylon powder, polyethylene powder, urea / formalin resin filler, and raw starch granules can also be added.

In the heat-sensitive recording medium of the present invention, the method of forming the recording layer is not particularly limited, and the recording layer can be formed according to a conventionally known technique. For example, a coating solution for a heat-sensitive recording layer is coated on a support with an appropriate coating device such as an air knife coater, a blade coater, a bar coater, a gravure coater, and a curtain coater.
Dry to form a recording layer.

The coating amount of the coating liquid is not particularly limited, and is generally 1.0 to 12 g / dry weight.
m ² , preferably in the range of 1.5 to 10 g / m ² . As the support, paper, plastic film, synthetic paper and the like are used, but paper is most preferably used in view of cost and applicability.

The thus obtained thermosensitive recording medium of the present invention
Even when exposed to high temperature conditions, reduction of whiteness and recording density is extremely small, and, even when exposed to an active gas such as NO _x, exhibits excellent characteristics of little discoloration of the recorded image and background portions Is what you do. If necessary, a protective layer may be provided on the front and / or back surface of the thermosensitive recording medium, or an intermediate layer may be provided between the support and the thermosensitive recording layer. Various known techniques in the field of recording medium production can be added.

[0041]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto. Unless otherwise specified, parts and% in the examples indicate parts by weight and% by weight, respectively. [Production Example 1 of Coloring Agent] 100 g of bisphenol A and 3 g of activated clay (K-500, manufactured by Japan Active Shirato Co., Ltd.) were placed in a flask and heated to 130 ° C. on an oil bath. After about 1 hour, the mixture becomes completely liquid, and the reaction was continued at 130 ° C. for 3 hours with stirring.
The reaction was carried out at 2 ° C. for 2 hours. After the reaction was completed, the temperature of the oil bath was lowered to 100 ° C., and 100 ml of toluene was added to dissolve the catalyst. The catalyst was separated by filtration and cooled to precipitate crystals.
After drying, the crystals were recrystallized from methanol to obtain 30.7 g of colorless crystals. As a result of analyzing the crystals by liquid chromatography, 3- (p-hydroxyphenyl) -1,1,3-
98.7% of trimethyl-5-indanol and 1,1-spirobis (3,3-dimethyl-6-hydroxyindane)
The composition was 1.3%. This composition was used as a colorant composition for a thermosensitive recording medium.

Example 1 (1) Preparation of Solution A 3-Di-n-butylamino-6-methyl-7-anilinofluorane 10 parts 2-benzyloxynaphthalene 25 parts Methylcellulose 5% aqueous solution 15 parts Water 120 parts The composition was pulverized with a sand mill until the average particle size became 1.5 μm. (2) Preparation of Solution B 15 parts of the color former of Production Example 1 p-hydroxybenzoic acid benzyl ester 10 parts 5% aqueous solution of methylcellulose 30 parts water 70 parts This composition was pulverized with a sand mill until the average particle size became 1.5 μm. did. (3) Formation of recording layer 170 parts of liquid A, 125 parts of liquid B, 30 parts of silicon oxide pigment (oil absorption 180 ml / 100 g), 20% aqueous starch oxide 1
50 parts and 55 parts of water were mixed and stirred to obtain a coating liquid. The obtained coating solution was applied to 50 g / m ² base paper so as to have a dry weight of 6 g / m ² and dried to obtain a thermosensitive recording medium.

Example 2 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that 4,4'-thiobis (2-methylphenol) was used instead of benzyl p-hydroxybenzoate in the preparation of Solution B. Obtained.

Example 3 A heat-sensitive recording material was prepared in the same manner as in Example 1, except that 2,2'-thiobis (4-t-octylphenol) was used in place of benzyl p-hydroxybenzoate in Preparation of Solution B. I got

Example 4 A heat-sensitive recording material was obtained in the same manner as in Example 1, except that 4,4'-dihydroxy-diphenylsulfone was used instead of benzyl p-hydroxybenzoate in Preparation of Solution B.

Example 5 In the preparation of Solution B, instead of benzyl p-hydroxybenzoate, 4,4 '-{1- [4- [2- (4-
A heat-sensitive recording material was obtained in the same manner as in Example 1 except that (hydroxyphenyl) -2-propyl] phenyl] ethylidene-bisphenol was used.

Example 6 Example 1 was repeated except that 4-methyl-2,4-bis (4-hydroxyphenyl) -pent-1-ene was used instead of benzyl p-hydroxybenzoate in Preparation of Solution B. In the same manner as in the above, a thermosensitive recording medium was obtained.

Example 7 A heat-sensitive recording material was obtained in the same manner as in Example 1, except that 4,4'-dihydroxybenzophenone was used instead of benzyl p-hydroxybenzoate in Preparation of Solution B.

Example 8 In the preparation of the solution A, 3- (N-i-yl) was used instead of 3-di-n-butylamino-6-methyl-7-anilinofluoran.
Pentyl) ethylamino-6-methyl-7-anilinofluoran was replaced with oxalic acid-di (p-methylbenzyl) ester instead of 2-benzyloxynaphthalene, Instead, 99.8% of 3- (p-hydroxyphenyl) -1,3,3-trimethyl-5-indanol and 0.2% of 1,1-spirobis (3,3-dimethyl-6-hydroxyindane) were added. A heat-sensitive recording material was obtained in the same manner as in Example 1 except that a coloring agent was used.

Example 9 In the preparation of solution A, 3-diethylamino-6-methyl-7-anilinofluoran was replaced with 3-di-n-butylamino-6-methyl-7-anilinofluoran, Oxalic acid-dibenzyl ester was used in place of benzyloxynaphthalene, and 3- (p-hydroxyphenyl) -1,3,3-
95.3% of trimethyl-5-indanol and 1,1-spirobis (3,3-dimethyl-6-hydroxyindane)
A heat-sensitive recording material was obtained in the same manner as in Example 1 except that a coloring agent containing 4.7% was used.

Example 10 In the preparation of solution A, 3-di-n-pentylamino-6-methyl-7-anilinofurane was used instead of 3-di-n-butylamino-6-methyl-7-anilinofluoran. In the preparation of Solution B, 3- (p-hydroxyphenyl) 1,3- (p-hydroxyphenyl) 1,
91.0% of 3,3-trimethyl-5-indanol and 1,1
Example 1 except that a color former containing 9.0% of 1-spirobis (3,3-dimethyl-6-hydroxyindane) was used.
In the same manner as in the above, a thermosensitive recording medium was obtained.

Example 11 In Preparation of Solution A, 1,2-bis (phenoxy) ethane was used in place of 2-benzyloxynaphthalene, and in Preparation of Solution B, benzyl p-hydroxybenzoate 1
A heat-sensitive recording material was obtained in the same manner as in Example 1 except that 5 parts and 5,4'-thiobis (6-t-butylphenol-m-cresol) were used instead of 0 parts.

Example 12 In Preparation of Solution A, 1,2-bis (3-methylphenoxy) ethane was used instead of 2-benzyloxynaphthalene, and in Preparation of Solution B, 5 parts of benzyl p-hydroxybenzoate were used instead of 10 parts of benzyl p-hydroxybenzoate. And a thermosensitive recording medium was obtained in the same manner as in Example 1 except that 5 parts of 2,2′-methylenebis (4-methyl-6-t-butylphenol) were used.

Example 13 In the preparation of Solution B, 5 parts and 5,4'-butylidenebis (6-tert-butylphenol-m-cresol) were used in place of 10 parts of benzyl p-hydroxybenzoate, except that A thermosensitive recording medium was obtained in the same manner as in Example 1.

Example 14 In the preparation of Solution B, 5 parts of 1,3,5-tris (3,3) was substituted for 10 parts of benzyl p-hydroxybenzoate.
A heat-sensitive recording material was obtained in the same manner as in Example 1, except that 5 parts of 5-di-t-butyl-4-hydroxybenzyl) isocyanuric acid was used.

Example 15 In the preparation of Solution B, 5 parts of 1,3,5-tris (3,3) was used instead of 10 parts of p-hydroxybenzoic acid benzyl ester.
5-di-t-butyl-4-hydroxybenzyl) -2,
A heat-sensitive recording material was obtained in the same manner as in Example 1 except that 5 parts of 4,6-trimethylbenzene was used.

Example 16 In the preparation of solution B, 3 parts of 4-i-propoxy-4'-hydroxy-diphenylsulfone and 2,2-methylenebis (4,6-di-butyl) were used instead of 10 parts of benzyl p-hydroxybenzoate. A heat-sensitive recording material was obtained in the same manner as in Example 1 except that 7 parts of a magnesium salt of (t-butyl) phenyl phosphate was used.

Example 17 The procedure of Example 1 was repeated, except that 25 parts of the color former of Preparation Example 1 was used instead of the color former of Preparation Example 1 and benzyl p-hydroxybenzoate in Preparation of Solution B. Thus, a thermosensitive recording medium was obtained.

Comparative Example 1 In the preparation of Solution B, 3- (p
-Hydroxyphenyl) -1,3,3-trimethyl-5
-A thermosensitive recording medium was obtained in the same manner as in Example 1 except that indanol was used.

Comparative Example 2 In the preparation of Solution B, 25 parts of 3- (p-hydroxyphenyl) 1,3,3-trimethyl-5-indanol was used instead of the color former of Production Example 1 and benzyl p-hydroxybenzoate. A heat-sensitive recording material was obtained in the same manner as in Example 1 except for using the same.

Comparative Example 3 A heat-sensitive recording material was obtained in the same manner as in Example 1 except that 25 parts of bisphenol A was used instead of the color former of Production Example 1 and benzyl p-hydroxybenzoate in Preparation of Solution B. Was.

[Evaluation of thermosensitive recording medium]
Zero types of thermosensitive recording media were recorded by Matsushita Simulator MF-1 (applied voltage: 16 V, pulse width: 2 ms). With respect to the obtained recorded image, the color density of the recorded image and the background density of the blank portion were measured by a Macbeth reflection densitometer (RD-914, manufactured by Macbeth Co., Ltd.). The density of the image and the degree of discoloration of the background were evaluated, and the results are shown in Table 1.

Heat resistance test The recording paper obtained in the color development test was tested at 60 ° C. for 16 hours.
After standing for a time, the color image and the density of the background were measured.

NO _X resistance test According to JIS L0855, the recording paper obtained by the color test was allowed to stand for 5 minutes while the air concentration was 500 ppm after NO _X gas was generated. The concentration in parts was measured.

[0065]

[Table 1]

[0066]

As is apparent from Table 1 results, according to the present invention, heat-sensitive recording material obtained in the present invention, the whiteness of the background portions, the storage stability of recorded images, resistance to NO _X of the recorded image and background portions It was an excellent thermal recording medium.

Continued on the front page (72) Inventor Hiromi Kawachi 1-26-11 Hisamatsudai, Fukuyama City, Hiroshima Prefecture (72) Inventor Shuya Sekiyama 2-15-23 Higashiizumioka, Toyonaka City, Osaka Prefecture Maison de Archamp 402 (72) Inventor Uchida Tadashi 1049-115 F-term (reference) Fukuki, Heigun-cho, Ikoma-gun, Nara Prefecture 2H026 AA07 BB02 BB24 BB25 BB30 BB39 DD12 DD23 DD45 DD53 FF01

Claims (4)

[Claims] 1. A heat-sensitive recording medium provided with a heat-sensitive recording layer containing a colorless or light-colored basic dye and a colorant capable of forming a color upon contact with the dye, wherein 3- (p) is used as the colorant.
-Hydroxyphenyl) -1,1,3-trimethyl-5
-A thermosensitive recording material characterized by using indanol and 1,1-spirobis (3,3-dimethyl-6-hydroxyindane) in combination. 2. 3- (p-hydroxyphenyl) -1,
1,3-trimethyl-5-indanol and 1,1-spirobis (3,3-dimethyl-6-hydroxyindane)
2. The heat-sensitive recording material according to claim 1, wherein the amount of used is from 100: 0.1 to 10 by weight. 3. The coloring agent according to claim 1, further comprising a compound represented by the general formula [1]:
3. The heat-sensitive recording material according to claim 1, wherein at least one phenol compound selected from the group [7] is included. Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image 4. A storage stabilizer comprising a compound represented by any one of formulas [8] to [1]
2] and / or the general formula [1
The heat-sensitive recording material according to any one of claims 1 to 3, wherein at least one compound selected from the group consisting of the hindered phenol phosphate compounds of 3) is contained in the heat-sensitive recording layer. Embedded image Embedded image Embedded image Embedded image Embedded image