JPH03221488A - Thermal recording body - Google Patents

Abstract

PURPOSE:To eliminate change in color by using, as basic dyes, 3-di-n- pentylamino-6-methyl-7-phenylaminofluoran and further putting, as substances which are thermally melted, oxalic dibenzyl and oxalic-bis(p-methylbenzyl) into a thermal recording layer. CONSTITUTION:A thermal recording layer containing colorless or light-colored basic dyes and coloration agents which generate colors when they come into contact with basic dyes is provided over supporters of a thermal recording body, wherein 3-di-n-pentyl-amino-6-methyl-7-phenylaminofluoran is used as basic dyes and further oxalic dibenzyl and/or oxalic-bis(p-methylbenzyl) are put into the thermal recording layer as substances which are thermally melted. As a result, recording bodies having high speed recording property and high whiteness and excellent property for holding whiteness can be prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a heat-sensitive recording medium, which has particularly excellent high-speed recording performance,
Furthermore, the present invention relates to a heat-sensitive recording medium free from background fog.

``Prior Art'' Conventionally, heat-sensitive recording materials utilize a coloring reaction between a colorless or light-colored basic dye and an organic or inorganic coloring agent to obtain a recorded image by bringing both coloring substances into contact with each other using heat. well known.

Recently, with remarkable progress in thermal recording methods, thermal faxes, thermal printers, etc. can all be faster.
Thermal faxes can record A4 size documents in 10 seconds, and thermal printers can record at over 120 characters/second. With the speed increase in the hardware field, there is a demand for heat-sensitive recording bodies that are excellent in suitability for high-speed recording. In order to enable high-speed recording, it is necessary to increase the sensitivity of a thermosensitive recording medium, and various thermofusible substances are included in the thermosensitive recording layer to increase the sensitivity. However, such high-sensitivity thermosensitive recording materials tend to undergo discoloration (fogging phenomenon) in blank areas due to long-term storage, and there is a strong demand for improvement.

``Problems to be Solved by the Invention'' In view of the current situation, the present inventors have conducted extensive research into improving the defects observed in heat-sensitive recording materials, and have found that 3-di-n-pentylamino is a basic dye. -6
- By using methyl-7-phenylaminofluorane in combination with a specific thermofusible substance, not only is it excellent in high-speed recording suitability, but the heat-sensitive recording material itself has a high whiteness and can be stored for a long time. It was discovered that a heat-sensitive recording material without a decrease in whiteness could be obtained, and the present invention was completed.

The present invention provides a heat-sensitive recording layer containing a colorless or light-colored basic dye and a coloring agent that changes color upon contact with the basic dye, on a support. In the thermosensitive recording medium, 3-di-n-pentylamino-6-methyl-7-
A heat-sensitive recording material characterized by using phenylaminofluorane and further containing dibenzyl oxalate and/or bis(p-methylbenzyl oxalate) as a heat-fusible substance in the heat-sensitive recording layer. .

"Function" In the present invention, as described above, 3-n-pentylamino-6-methyl-7-phenylaminofluorane is used as the basic dye, and by using this together with a specific thermofusible substance, The heat-sensitive recording material has excellent suitability for high-speed recording, has a high degree of whiteness, and has extremely high commercial value, with no loss of whiteness even when stored in an external environment for a long time. be.

These thermofusible substances and 3-di-n-pentylamino-
The proportion of the basic dye used in combination with 6-methyl-7-phenylaminofluorane is not necessarily limited;
50 to 700 parts by weight, preferably 1
It is desirable to blend about 00 to 500 parts by weight of a thermofusible substance.

In the present invention, the following general formula (13
It is a more preferable embodiment to contain at least one selected from the compounds represented by ~[■], since the fastness of the recorded image is also improved.

In the formula B8C, R1 represents a branched alkyl group having 3 to 8 carbon atoms, a cycloalkyl group, a phenyl group, or a halogen atom, and R2 represents a hydrogen atom, a branched alkyl group having 3 to 8 carbon atoms, or Indicates a halogen atom, Ri, Rs~R8
each represents a hydrogen atom or a lower alkyl group. R4 represents a hydrogen atom, a halogen atom, or an alkyl group having 8 or less carbon atoms.

X represents -o--s--5-s--5o2 R1 or -C-, and represents Rq, R+. each represents a hydrogen atom or an alkyl group having 8 or less carbon atoms. Furthermore, R7 and R1° may be combined with each other to form a ring. Z represents a linear or branched alkylene group having 8 or less carbon atoms. ] General formula [I] ~ [I
Specific examples of the compound represented by V] include the following compounds.

[Compound represented by general formula (1)] 4.4'-butylidene bis(2-tert-butyl 5-
methylphenol), 4,4'-butylidene bis(2
-tert-butyl-6-methylphenol), 4.4
'-Butylidene bis (2,6-di-tert-butylphenol), 4,4'-butylidene bis (2-cyclohexylphenol), 4゜4'-butylidene bis (2
-phenylphenol)4.4'-cyclohexylidenebis(2-tertbutyl-5-methylphenol),
4.4'-cyclohexylidene bis(2-tert-butyl-6methylphenol), 4.4'-cyclohexylidene bis(2,6-tert-butylphenol) 4.4'-cyclohexylidene bis(2-tert-butylphenol) -cyclohexylphenol), 4.4'-cyclohexylidenebis(2-phenylphenol), 4.4'thiobis(2-phenylphenol),
-tert-butyl-5-methylphenol), 4.4
'-thiobis(2-tert-butyl-6-methylphenol), 4,4'-thiobis(2,6-di-tert
t-butylphenol), 4゜4'-thiobis(2-
cyclohexylphenol)4.4'-thiobis(2-
phenylphenol), 4.4'-isopropylidene bis(2,6-dichlorophenol), 4.4'-isopropylidene bis(2,6-dibromophenol), 4.
4'-cyclohexylidene bis(2,6-dichlorophenol), 4.4'-cyclohexylidene bis(2,6-dichlorophenol),
6-dibromophenol), bis(4-hydroxy-3
, 5-dichlorophenyl) sulfone, bis(4-hydroxy-3,5-dibromophenyl) sulfone, bis(4
-hydroxy-3,5-dichlorophenyl) sulfide, bis(4-hydroxy-3,5-dibromophenyl)
Sulfide, bis(4-hydroxy-3,5-dichlorophenyl) ether, bis(4-hydroxy-3,5-
dibromophenyl) ether, bis(4-hydroxy-
3,5-dichlorophenyl) disulfide, bis(4-
hydroxy-3,5-dibromophenyl) disulfide, etc.

[Compound represented by general formula (II)] 2.2'-methylenebis(4-methyl-5-tert-
butylphenol), 2,2'-methylenebis(4-
ethyl-5-tert-butylphenol), 2.2'
-Methylenebis(4,6-tert-butylphenol), 2.2'-methylenebis(4°6-dichlorophenol), 2.2'-ethylidenebis(4,6-tert-butylphenol), 2.2 '-thiobis(4-methyl-6-tert-butylphenol), 2
．． 2'-thiobis(4-ethyl-6tert-butylphenol), 2,2'-thiobis(4,6-tert-butylphenol)
t-butylphenol), 2,2'-dithiobis(4
-methyl-6tert-butylphenol), bis(2
-Hydroxy-3-tert-butyl-5-methylphenyl)sulfone, bis(2-hydroxy-3-tert
-butyl-5-ethylphenyl)sulfone, bis(2-
hydroxy-3,5-dichlorophenyl) sulfone, etc.

[Compound represented by general formula [111]] 1.1.3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 11.3-tris(3-methyl-4-hydroxy 5-tert-butylphenyl)butane, 1. 1. 3 tris (3,5-tert-
Butyl-4-hydroxyphenyl)butane, 1 1 3
-tris(3,5-dichloro-4-hydroxyphenyl)butane, 1.1.3-tris(3,5-dibromo4-
hydroxyphenyl)butane, 1,1,3 tris(3-
cyclohexyl-4-hydroxy-6-methylphenyl)
Butane, 1.1.3-)lis(3-phenyl-4-hydroxyphenyl)butane, 2-methyl-1,1,3-tris(2-methyl-4-hydroxy-5tert-butylphenyl)butane, 2 -ethyl-1,1,3-)lis(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,1.3-)lis(2-methyl-
4-Hydroxy-5tert-butylphenyl)hexane, 1,1.3-)lis(2-methyl4-hydroxy-
5-tert-butylphenyl)hebutane, 2-ethyl-1,1,3-1-lis(2-methyl-4-hydroxy-5tert-butylphenyl)hexane, and the like.

(Compound represented by general formula (IV)) 1-(bis(4-hydroxyphenyl)methyl)-3-
(1-(4-hydroxyphenyl)ethyl) Hensen,
1-[bis(4-hydroxyphenyl)methyl)-4-
(1(4-hydroxyphenyl)ethyl)Hensen, 1
-(bis(4-hydroxyphenyl)methyl: l -3
-(1-methyl-1-(4-hydroxyphenyl)ethyl]benzene, 1[bis(4-hydroxyphenyl)methyl]4-[1-methyl-1-(4-hydroxyphenyl)ethyl]benzene, 1- (1,1-bis(4-hydroxyphenyl)ethyl)-3-[:l-(4-hydroxyphenyl)ethyl]benzene, 1-[1,1-bis(4-hydroxyphenyl)ethyl)-4 -(1-(4
-hydroxyphenyl)ethyl]benzene, 1-[1,
1-bis(4-hydroxyphenyl)ethyl]-3-(
1-methyl-1-(4-hydroxyphenyl)ethyl]
Hensen, 1-(1,1-bis(4-hydroxyphenyl)ethyl)-4-(1-methyl-1-(4hydroxyphenyl)ethyl)benzene, and the like.

Of course, two or more of the compounds represented by the above general formulas (I) to (IV) can also be used in combination.

Note that the amount of phenolic compounds with these specific structures to be used is not necessarily limited, but
It is desirable to blend the phenolic compound in an amount of about 5 to 300 parts by weight, preferably about 10 to 200 parts by weight, per 100 parts by weight of 3-di-n-pentylamino-6methyl-7-phenylaminofluorane.

Various coloring agents are known, including the following compounds.

44'-isopropylidene diphenol, 4゜4'-cyclohexylidene diphenol, 4.4'-(1,3-
dimethylbutylidene) diphenol, 1,3-bis(p
-Hydroxy-α-cumyl)benzene, I,4-bis(
p-hydroxy-α-cumyl) Hensen, p, p'-biphenol, 4-phenylphenol, 4-α-ritanylphenol, 4-hydroxydiphenyl ether, 4.
4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,47-dihydroxydiphenyl sulfone, 24'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxyhensiphenone, bis (3-
Allyl-4-hydroxyphenyl)sulfone, 4-hydroxydiphenylsulfone, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-chlorodiphenylsulfone, 34-dihydroxy-4'-methyldiphenylsulfone, 4- Hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-3'
, 4'-tetramethylenediphenylsulfone, methyl-
4-Hydroxybenzoate, Benzyl-4-hydroxybenzoate, Methyl-bis(4-hydroxyphenyl)acetate, Ethyl-bis(4-hydroxyphenyl)acetate, Butyl-bis(4-hydroxyphenyl)acetate, Hensyl-bis(4-hydroxyphenyl)acetate, -hydroxyphenyl)acetate, bis(4-hydroxyphenyl)acetic acid-2-phenoxyethyl ester, P-hydroxy-
N-(2-phenoxyethyl)henzensulfonate, dimethyl 4-hydroxyphthalate, 1,5-bis(4
-hydroxyphenylthio)-3-oxapencune, l
.

7-bis(4-hydroxyphenylthio)-3゜5-dioxahebutane, 1,8-bis(4-hydroxyphenylthio)-3,6-dioxaoctane, (4-hydroxyphenylthio)acetic acid-2 Phenolic compounds such as (4-hydroxyphenylthio)ethyl ester; benzoic acid, 4-tertbutylbenzoic acid, 4-chlorobenzoic acid, 4-nitrobenzoic acid, phthalic acid monoethyl ester,
Tetrachlorophthalic acid mono(2-hydroxyethyl) ester, salicylic acid, 3-isopropylsalicylic acid, 3
-Phenylsalicylic acid, 3-cyclohexylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 3-methyl-5-hendylsalicylic acid, 3-phenyl-5-α-
Cumyl salicylic acid, 3゜5-di(α-methylbenzyl)salicylic acid, 4(2-phenoxyethoxy)salicylic acid, 4(2-(p-methoxyphenoxy)ethoxy)salicylic acid, 2-hydroxy-1-hensyl-3naphthoate Aromatic carboxylic acids such as acids, salts of these organic coloring agents with polyvalent metals such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin, and nickel, and antipyrine complexes of zinc thiocyanate. Metal complex compounds, and 1゜3-diphenylthiourea, 1.3-bis(m-chlorophenyl)thiourea, 1.3-bis(
urea derivatives such as m-)lyl)thiourea, 1,3-bis(m-trifluoromethylphenyl)thiourea, and the like.

Among these, 44'-isopropylidenediphenol is more preferred because it is industrially inexpensive and has excellent coloring ability.

The proportion of these coloring agents and 3-di-n-pentyl-7-phenylaminofluorane in combination is not necessarily limited, but is 100 to 700 parts by weight per 100 parts by weight of the basic dye. , more preferably 15
It is desirable to blend about 0 to 600 parts by weight of a coloring agent.

In addition, in the thermosensitive recording material of the present invention, 3-
The use of di-n-pentylamino-6-methyltuphenylaminofluorane has important characteristics, but within the range that does not impede the desired effects of the present invention,
One or more other colorless or light-colored basic dyes can be used in combination. Examples of basic dyes that can be used in combination include the following compounds.

3.3-bis(p-dimethylaminophenyl)6-dimethylaminophthalide, 3.3-bis(p-dimethylaminophenyl)phthalide, 3-(4-dimethylaminophenyl)-3-(4-diethylamino- 2-methylphenyl)-6-(dimethyla5))phthalide, 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-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-
Triarylmethane dyes such as dimethylaminophthalide, 4,4'-bis-dimethylaminobenzhydrylbenzyl ether, N-halophenyl-leucoauramine, N-2,4゜5-trichlorophenylleucoauramine, etc. Diphenylmethane dye i3,3-bis(1,i
-bis(4-pyrrolidinophenyl)ethylene-2-yl)-4,5,6,7-titrabromophthalide, 3.3-
Bis[1-(4-methoxyphenyl)-1-(4-dimethylaminophenyl)ethylene-2-yl)-4,5,6
,7-titrachlorophthalite,3,3-bis(1-(4
-methoxyphenyl)-1(4-pyrrolidinophenyl)
Divinyl phthalide dyes such as ethylene 2-yl]-4.5,6.7-titrachlorophthalite; Thiazine dyes such as benzoyl leucomethylene blue and p-nitrohenduyl leucomethylene blue; 3-methyl-spiro-dinaphthopyran , 3-ethyl-spiro-dinaphthopyran, 3
Spiro dyes such as -phenyl-spirodinaphthopyran, 3-benzyl-spiro-dinaphthopyran, 3-methyl-naphtho(6'-methoxybenzo)spiropyran, 3-propyl-spirodibenzopyran; rotamine-B-anilinolactam, Lactam dyes such as rhodamine (p-nitroanilino) lactam and rhodamine (0-chloroanilino) lactam; 3-dimethylamino-7-methoxyfluoran, 3-diethylamino-6-methoxyfluoran, 3-diethylamino-7-methoxy Fluorane, 3
-diethylamino-7-lyrolofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6,7-dimethylfluorane, 3-(N
-ethyl-p-toluidino)-7methylfluorane, 3
-diethylamino-2N-acetyl-N-methylaminofluorane, 3-diethylamino-7-N-methylanofluorane, 3-diethylamino-7-dipendylaminofluorane, 3-diethylamino-7-N-methyl-
N-hensylaminofluorane, 3-diethylamino-
7-N-chloroethyl-N-methylaminofluorane,
3-diethylamino 7-N diethylaminofluorane, 4-benzylamino 8-diethylamino-benzo(a
) Fluorane, 3-(4-(4-dimethylaminoanilino)anilino)-7-lichlor6-methylfluoran, 8(1-(4-dimethylaminoanilino)anilino)
-henzo(a) fluorane, 3-(N-ethyl-p-1
-luidino)-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-diethylamino-7-(2-carbomethoxy-phenylamino)fluorane, 3-(N-ethyl-N-isoamylamino)-6-methyltuphenyl Aminofluorane, 3-(N-cyclohexyl-N-methylamino)-6-methyltwophenylaminofluorane, 3-pyrrolidino-6-methyl-7-phenylaminofluorane, 3-piperidino-6-methyl-7 -phenylaminofluorane, 3-diethylamino-6-methyl=
7-xylidinofluorane, 3-diethylamino-7-
(o-chlorophenylamino)fluoran, 3-dibutylamino-7-(o-chlorophenylamino)fluoran, 3-(N-ethyl-N=tetrahydrofurfurylamino)-6-methyltwophenylaminofluorane, 3
-(N-methyl-N-n-propylaξ))-6-methyl-7-phenylaminofluorane, 3-(N-ethyl-N-i-butylamino)-6-methyl-7phenylaminofluorane orane, 3-(N-methylNn-hexylamino)-6-methyl-7-phenylaminofluorane,
1-(N-ethyl-Nn-hexylamino))-6-methyl-7-phenylaminofluorane, 3-(N-ethyl-Ncyclopentylamino)-6-methyl-7-phenylaminofluorane, 3 - (N-(3-ethoxypropyl)-N-methylamine]-6-methylfuphenylaminofluorane, 3-[N-ethyl-N-(3-ethoxypropyl)amino]6-methyl-7- Fenilua ξ
nofluorane, 3-diethylamino-7-[m-(trifluoromethyl)phenylaminofluorane, 3-diethylamino-7-(o-fluorophenylamino)fluorane, 3-dibutylamino-7-(0-fluorophenylamino) Fluoran dyes such as fluoran, 3-diethylamino-6-chloro-7-phenylaminofluorane; 3,6-bis(dimethylamino)fluorene-9-
spiro-3'(6'-dimethylamino)phthalide, 3-
Diethylamino-6-(N-allyl-N-methylamino)fluorene-9-spiro-3'-(6'-dimethylamino)phthalide, 3,6-bis(dimethylamino)
-spiro(fluorene-9,6'-6' Hchromeno(43-b)indole L3,6bis(dimethylamino)-3'-methyl-spiro[fluorene-9,6' -
6'H-chromeno(4,3-b)indole), 3.
6-bis(diethylamino)-3'-methylspiro[fluorene 9.6'-6' H-chromeno(4,3-b)
Indole] and other fluorene dyes. Of course, the dyes are not limited to these dyes.

Coating liquids containing these heat-sensitive materials are generally prepared by using water as a dispersion medium and using a stirring/pulverizing machine such as a ball mill or an attriter sand grinder to prepare the various heat-sensitive materials described above separately or by mixing two or more of them. It is prepared by dispersing.

Such coating liquids usually contain starches and binders as binders.
Hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, gum arabic, polyvinyl alcohol, styrene/maleic anhydride copolymer salt, styrene/acrylic acid copolymer salt, styrene/butadiene copolymer emulsion, etc. are total solids. It is blended in an amount of about 10 to 40% by weight, preferably about 15 to 30% by weight.

Furthermore, various auxiliary agents can be added to the coating liquid.
For example, dispersants such as sodium dioctyl sulfosuccinate, sodium dodecylbenzene sulfonate, sodium salt of lauryl alcohol sulfate, fatty acid metal salts, ultraviolet absorbers such as triadurine, and local foaming agents thereof,
Examples include fluorescent dyes and colored dyes. In addition, in order to prevent the heat-sensitive recording medium from causing sticking due to contact with recording equipment or recording heads, dispersions of stearic acid, polyethylene, carnauba wax, paraffin wax, zinc stearate, calcium stearate, esterwanx, etc. are added to the coating liquid. It is also possible to add an emulsion or the like. In addition, inorganic pigments such as kaolin, clay, talc, calcium carbonate, calcined clay, titanium oxide, diatomaceous earth, fine particulate anhydrous silica, and activated clay can be added to improve the adhesion of debris on the recording head. .

As the support, paper, plastic film, synthetic paper, etc. can be used, but yam is most preferably used in terms of price, coating suitability, etc. Further, the amount of the coating liquid to be applied to the support for forming the recording layer is not particularly limited, and is usually 2 to 1 on dry weight.
It is adjusted within a range of about 2 g/m, preferably about 3 to 10 g/m.

It is also possible to provide an overcoat layer on the recording layer for purposes such as protecting the recording layer, and it is of course also possible to provide a protective layer on the back side of the support or an undercoat layer on the support. Various known techniques in the field of heat-sensitive recording material manufacturing can be added. The heat-sensitive recording material of the present invention thus obtained has suitability for high-speed recording, has no tendency for recorded images to fade, has no fogginess in blank areas, and has excellent properties in terms of debris adhesion to recording heads (piling). It is something that can be demonstrated.

"Example" The present invention will be described in more detail with reference to Examples below, but the present invention is of course not limited to these.

Further, unless otherwise specified, parts and % in the examples indicate parts by weight and % by weight, respectively.

Example 1 ■ Formation of undercoat layer Calcined clay (trade name: Ancilesox, manufactured by Engelhardt) 100 parts styrene-butadiene copolymer latex (solid content = 50%)
15 parts polyvinyl alcohol 10% aqueous solution 30 parts
Department water 2
A coating solution for undercoating was prepared by mixing 00 parts of the above composition. The obtained coating liquid was applied to a high-quality paper of 50 g/r+ (coating amount after drying was 10 g/r+) and dried to form an undercoat layer.

■ Preparation of solution A 3-di-n-pentylamino-6-methyl 7-phenylaminofluorane 10 parts dibenzyl oxalate
20 parts methylcellulose 5% aqueous solution
20 parts water
110 parts of this composition was ground with a sand grinder until the average particle size was 2 μm.

■ Preparation of Solution B 4. 30 parts of 4'-isopropylidenediphenol 5% aqueous solution of methylcellulose 31 parts of water
70 parts of this Mi kaimono was ground with a sand grinder until the average particle size was 2 μm.

■ Formation of recording layer 160 parts of liquid A, 130 parts of liquid B, silicon oxide pigment (oil absorption 1
80ml/100g), 150 parts of a 20% oxidized starch aqueous solution, and 160 parts of water were mixed and stirred to prepare a coating liquid. The resulting coating liquid was applied onto the undercoat layer at a dry weight of 5.0 g/rn.
A thermosensitive recording paper was obtained by coating and drying so as to obtain the following.

Example 2 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that in the preparation of Liquid A, bis(P-methylbenzyl oxalate) was used instead of dihenzyl oxalate.

Example 3 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that the following liquid C was used instead of liquid A in Example 1.

■ C lacquer preparation 3-di-n-pentylamino-6-methyl-7 phenylaminofluorane 10 parts 4.4'-butylidene bis(2-tert-butyl 5-methylphenol) 5 parts dihendyl oxalate
20 parts methylcellulose 5% aqueous solution
20 parts water
105 parts of this composition was ground with a sand grinder until the average particle size was 2 μm.

Examples 4-8 In the preparation of C lacquer, 4,4'-butylidene bis(2-t
ert-butyl-5-methylphenol) instead of
Five types of thermal recording papers were obtained in the same manner as in Example 3, except that the following compounds were used.

Example 47 2'-methylenebis(4-methyl-6-
tert-butylphenol) Example 5: 4,4'-thiobis(,2tert-phthyl-5-methylphenol) Example 6: 4,4'-isopropylidene bis(2,6-
Example 7: 1,1,3-tris(2-methyl4-hydroxy-5-tert-butylphenyl)butane Example 8: 1-[1,1-bis(4-hydroxyphenyl)ethyl] -1-[1-Methyl-1-(4-hydroxyphenyl)ethylcobenzene Comparative Example I Heat-sensitive recording paper was prepared in the same manner as in Example 1 except that water was used instead of dibenzyl oxalate in the preparation of liquid A. Obtained.

Comparative Example 2 A thermosensitive recording paper was obtained in the same manner as in Example 1, except that stearamide was used instead of dibenzyl oxalate in the preparation of Liquid A.

Comparative Example 3.4 Two types of thermosensitive recordings were made in the same manner as in Example 1, except that the following compound was used instead of 3-di-n-pentylamino 6-methyl-7-phenylaminofluoran in the preparation of Solution A. Got paper.

Comparative Example 3: 3-(N-cyclohexyl-N-methylaξ
))-6-Methyl-7-phenylamino)fluoran Comparative Example 4: 3-(N-ethyl-N-isoamylamino)
-6-Methyl-7-phenylaminofluorane Comparative Example 5.6 In the preparation of C lacquer, 3-di-n-pentylamino-6-
Two types of thermal recording paper were obtained in the same manner as in Example 3, except that the following compound was used instead of methyl-7-phenylagonofluorane.

Ratio IHII 5: 3- (N-cyclohexyl-N
-Methylamino)-6-methyl-7-phenylaminofluoran Comparative Example 6:3 (N-ethyl-N-isoamylamino)-6-methyl-7-phenylaminofluoran 14 types of thermal records thus obtained Transfer paper to Kyocera simulator (voltage: 15V, pulse cycle: 5ms
Using e c), pulse width 0.30 m5ec and 0
．． The color density was measured using a Maches i meter (R1)-100R (using an amber filter), and the results are shown in Table 1.

In addition, the whiteness of the surface of the recording layer of the recording paper, and the drying conditions of the recording paper at a high temperature of 60°C and 40'C190
The whiteness of the surface of the recording layer after being left for 3 days under high humidity conditions of %RH was measured using a Hunter whiteness meter, and the results are shown in Table 1.

Table 1 "Results" As is clear from the results in Table 1, the heat-sensitive recording material of the present invention was a recording material that had excellent high-speed recording suitability, high whiteness, and excellent whiteness retention.

Claims (2)

[Claims] (1) A colorless or light-colored basic dye on the support,
In a heat-sensitive recording material provided with a heat-sensitive recording layer containing a coloring agent capable of coloring upon contact with the basic dye, 3-di-n-pentylamino-6-methyl-7-phenylamino is used as the basic dye. A heat-sensitive recording material comprising fluoran and further containing dibenzyl oxalate and/or sulfuric acid-bis(p-methylbenzyl) as a heat-fusible substance in the heat-sensitive recording layer. (2) In the heat-sensitive recording layer, the following general formulas [I] to [
The heat-sensitive recording material according to claim (1), which contains at least one compound selected from the compounds represented by IV]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼[II] ▲There are mathematical formulas, chemical formulas, tables, etc.▼[III] ▲There are mathematical formulas, chemical formulas, tables, etc.▼[ IV] [In the formula, R_1 represents a branched alkyl group having 3 to 8 carbon atoms, a cycloalkyl group, a phenyl group, or a halogen atom, and R_2 represents a hydrogen atom, a branched alkyl group having 3 to 8 carbon atoms, or a halogen atom. Indicates atoms, R_3, R_
5 to R_8 each represent a hydrogen atom or a lower alkyl group. R_4 represents a hydrogen atom, a halogen atom, or an alkyl group having 8 or less carbon atoms. X represents -O-, -S-, -S-S-, -SO_2-, or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and R_9 and R_1_0 are each a hydrogen atom or an alkyl group having 8 or less carbon atoms. shows. Furthermore, R_9 and R_1_0 may be combined with each other to form a ring. Z represents a linear or branched alkylene group having 8 or less carbon atoms. ]