JP2000135865A - Heat-sensitive recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve recording sensitivity by using a specific diphenylsulfone crosslinking type compound as an organic developer and using an aromatic compound having a specific aminosulfonyl group as a sensitizer. SOLUTION: A heat-sensitive color developing layer contains a diphenylsulfone crosslinking type compound represented by formula I (X and Y are each linear or branched 1-12C saturated or unsaturated hydrocarbon group which may be different and may have an ether bond, R1 to R6 are each independently a halogen atom, 1-6C alkyl group, or alkenyl group, m, n, p, q, r and t are each an integer of 0 to 4, and a is an integer of 1 to 10) as an organic developer, and 0.01 to 2 pts. of at least one type of a compound represented by formula II (R7 is a halogen atom, u is an integer of 0 to 2, and R8 is a substituted phenyl group) to 1 pt. of the developer represented by the formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive recording medium having excellent storage stability of a color image and excellent color sensitivity.

[0002]

2. Description of the Related Art In general, a thermosensitive recording medium is prepared by grinding and dispersing a colorless or pale-colored basic colorless dye and an organic developer such as a phenolic compound into fine particles, and then mixing the two. A paint obtained by adding a binder, a filler, a sensitivity enhancer, a lubricant and other auxiliaries is applied to a support such as paper, synthetic paper, film, plastic, and the like.
Color is formed by an instantaneous chemical reaction due to heating of a thermal head, hot stamp, hot pen, laser light, etc., and a recorded image is obtained. Thermal recording media are facsimile, computer
Terminal printer, automatic ticket vending machine, measurement recorder
Widely used for etc. In recent years, high-speed printing and high-speed image formation have become possible along with the diversification of recording apparatuses and the advancement of performance, and higher quality is required for the recording sensitivity of a thermosensitive recording medium.

As a method for satisfying this requirement, it has been proposed to use a dye and a developer together with a sensitizer. For example, when the color developer consists of a phenolic compound represented by bisphenol A, p-benzylbiphenyl (JP-A-60-82382) and benzyl p-benzyloxybenzoate (JP-A-57-201691) No.), benzyl naphthyl ether (JP-A-58-87094) and the like have been used as suitable sensitizers. When using a sensitizer,
When heated, the sensitizer first melts, and it dissolves the basic dye and the developer, so that the two are mixed at the molecular level to induce a color-forming reaction. It is important to consider the color developer.

[0004] In particular, when the recording sensitivity is improved by a sensitizer or the like, the storage stability of the recorded image often cannot be maintained. Specifically, a sebum component adheres or a plasticizer (DOP, DOA, etc.) contained in a wrap film such as a PVC film.
Etc.), there still remain disadvantages such as a marked decrease in image density and decoloration. In recent years, with increasing use in fields such as labels where reliability is required for recorded images, high storage stability against plasticizers, fats and oils contained in packaging materials and the like has been achieved. There is a need for the recording materials shown. So far, thermal recording media using various auxiliaries such as various dyes, developers, or storage stabilizers have been proposed, but no satisfactory one has been found.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to greatly improve the recording sensitivity of a thermosensitive recording medium having a high stability against a plasticizer or the like by using a diphenylsulfone crosslinked compound as a color developer. It is intended to provide a thermal recording medium.

[0006]

Means for Solving the Problems The inventors of the present invention have made intensive studies to develop a thermosensitive recording medium having the above-mentioned performance. As a result, a diphenylsulfone cross-linked compound was used as a developer, and an aminosulfonyl compound was used as a developer. By using an aromatic compound having a group (—SO 2 NH—) as a sensitizer,
The recording sensitivity was greatly improved, and the present invention was completed. That is, the present invention relates to a heat-sensitive recording medium provided with a heat-sensitive coloring layer containing a colorless or light-colored basic colorless dye and an organic developer as main components on a support, wherein the heat-sensitive coloring layer is an organic dye. The following general formula (I) as a developer
Containing a diphenyl sulfone cross-linked compound represented by
The compound represented by the following general formula (II) is used as a sensitizer in an amount of 0.0 with respect to 1 part of the developer represented by the following general formula (I).
This was achieved by containing at least one kind in a proportion of 1 to 2 parts.

[0007]

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[Wherein, X and Y may be different from each other, may be linear or branched, and may have 1 to 12 carbon atoms;
Represents a hydrocarbon group which may have an unsaturated or ether bond, or

[0009]

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[0010] Or,

[0011]

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(R represents a methylene group or an ethylene group, T represents a hydrogen atom or a C ₁ -C ₄ alkyl group). R _{1 to} R ₆ are each independently a halogen atom, C _{1 to} C ₆
Represents an alkyl group or an alkenyl group. Also, m, n, p,
q, r, and t represent an integer from 0 to 4;
_{1 to} R ₆ may be different from each other. a is 1 to 10
Represents an integer. ]

[0013]

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(Wherein, R ₇ represents a halogen atom or an alkyl group having 1 to 6 carbon atoms, and u represents an integer of 0 to 2.)
R ₈ represents an unsubstituted or substituted phenyl group or a benzyl group, and the substituent represents a halogen atom, a halogen-substituted alkyl group or an alkyl group having 1 to 6 carbon atoms. )

In the present invention, at least one diphenylsulfone cross-linkable compound represented by the general formula (I) is used as an organic developer. The diphenylsulfone bridged compound of the general formula (I) is described in JP-A-10-29969. In the general formula (I), X
Specific examples of the groups represented by Y and Y include the following. Methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, methylmethylene group, dimethylmethylene Group, methylethylene group, methyleneethylene group, ethylethylene group, 1,2-dimethylethylene group, 1-methyltrimethylene group, 1-methyltetramethylene group, 1,3-dimethyltrimethylene group, 1-ethyl-4 -Methyl-tetramethylene group, vinylene group, propenylene group, 2-butenylene group, ethynylene group, 2-butynylene group, 1-vinylethylene group, ethyleneoxyethylene group, tetramethyleneoxytetramethylene group, ethyleneoxyethyleneoxyethylene Group, ethylene oxide Methylene oxyethylene group, 1,3-dioxane-5,5-bismethylene group,
1,2-xylyl group, 1,3-xylyl group, 1,4-xylyl group, 2-hydroxytrimethylene group, 2-hydroxy-2-methyltrimethylene group, 2-hydroxy-2
-Ethyltrimethylene group, 2-hydroxy-2-propyltrimethylene group, 2-hydroxy-2-isopropyltrimethylene group, 2-hydroxy-2-butyltrimethylene group and the like.

The alkyl group or alkenyl group of R _{1 to} R ₆ is a C _{1 to} C ₆ alkyl group or a C _{1 to} C ₆ alkenyl group. Specific examples include a methyl group and an ethyl group. ,
n-propyl group, isopropyl group, n-butyl group, se
c-butyl group, tert-butyl group, n-pentyl group,
Isopentyl group, neopentyl group, tert-pentyl group, n-hexyl group, isohexyl group, 1-methylpentyl group, 2-methylpentyl group, vinyl group, allyl group,
Isopropenyl group, 1-propenyl group, 2-butenyl group, 3-butenyl group, 1,3-butanedienyl group, 2-
And a methyl-2-propenyl group. The halogen atom represents chlorine, bromine, fluorine, and iodine. The developer used in the present invention has the general formula (I)

[0017]

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[Where X, Y, R _{1 to} R ₆ , m, n, p,
q, r, t and a are the same as defined above) and at least one diphenylsulfone cross-linked compound represented by the following formula:
I)

[0019]

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[Wherein R _{1 to} R ₄ , m, n, p and q are the same as those described above, and Z represents a saturated or unsaturated C _{1 to} C 12 which may be linear or branched. Represents a hydrocarbon group which may have an ether bond, or

[0021]

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Alternatively,

[0023]

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(R represents a methylene group or an ethylene group, T represents a hydrogen atom or a C ₁ -C ₄ alkyl group). Is very effective when used in combination with at least one diphenylsulfone derivative represented by the formula These mixing methods may be mixed as a powder, added at the time of adjusting and dispersing the coating liquid, or added in the state of a dispersion. Also,
It is more effective to use a composition containing these at the same time.

The content ratio of the diphenylsulfone cross-linked compound represented by the general formula (I) and the diphenylsulfone derivative represented by the general formula (III) is arbitrary, but the diphenylsulfone represented by the general formula (I) is not limited. The cross-linking type compound is preferably present in an amount of 0.05 to 99% by weight. further,
It is particularly preferred that the content be 1 to 90% by weight, specifically 5 to 80% by weight. When two or more compounds of the general formula (I) are contained, the total thereof is this% by weight.
Particularly preferred compositions are those containing two or more kinds of compounds represented by the general formula (IV) which differ only in the value of b. At this time, the diphenylsulfone crosslinked compound represented by the general formula (I) b = 1 to 10 and the general formula (III)
Is the case where b = 0.

[0026]

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(Wherein X, R ₁ and m are the same as those described above) The compound represented by the general formula (I) can be specifically exemplified as follows. (I-1) 4,4'-bis [4- [4- (4-hydroxyphenylsulfonyl) phenoxy] -2-trans-
Butenyloxy] diphenylsulfone (I-2) 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-4-butyloxy] diphenylsulfone (I-3) 4,4'-bis [4- (4- (Hydroxyphenylsulfonyl) phenoxy-3-propyloxy] diphenylsulfone (I-4) 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-2-ethyloxy] diphenylsulfone (I-5) 4- [ 4- (4-hydroxyphenylsulfonyl) phenoxy-4-butyloxy] -4 '-[4-
(4-hydroxyphenylsulfonyl) phenoxy-
3-propyloxy] diphenylsulfone (I-6) 4- [4- (4-hydroxyphenylsulfonyl) phenoxy-4-butyloxy] -4 '-[4-
(4-hydroxyphenylsulfonyl) phenoxy-
2-ethyloxy] diphenylsulfone (I-7) 4- [4- (4-hydroxyphenylsulfonyl) phenoxy-3-propyloxy] -4 '-[4
-(4-hydroxyphenylsulfonyl) phenoxy-2-ethyloxy] diphenylsulfone (I-8) 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-5-pentyloxy] diphenylsulfone (I-9 ) 4,4'-Bis [4- (4-hydroxyphenylsulfonyl) phenoxy-6-hexyloxy] diphenylsulfone

(I-10) 4- [4- [4- (4-hydroxyphenylsulfonyl) phenoxy] -2-trans-butenyloxy] -4 '-[4- (4-hydroxyphenylsulfonyl) phenoxy-4- Butyloxy)
Diphenylsulfone (I-11) 4- [4- (4-hydroxyphenylsulfonyl) phenoxy-2-trans-butenyloxy]
-4 '-[4- (4-hydroxyphenylsulfonyl)
Phenoxy-3-propyloxy] diphenylsulfone (I-12) 4- [4- [4- (4-hydroxyphenylsulfonyl) phenoxy] -2-trans-butenyloxy] -4 '-[4- (4-hydroxyphenyl Sulfonyl) phenoxy-2-ethyloxy] diphenylsulfone (I-13) 1,4-bis [4- [4- [4- (4-hydroxyphenylsulfonyl) phenoxy-2-trans-butenyloxy] phenylsulfonyl] phenoxy]- Cis-2-butene (I-14) 1,4-bis [4- [4- [4- (4-hydroxyphenylsulfonyl) phenoxy-2-trans-butenyloxy] phenylsulfonyl] phenoxy] -trans-2-butene (I-15) 4,4'-bis [4- [4- (2-hydroxyphenyls) Ruphonyl) phenoxy] butyloxy]
Diphenyl sulfone (I-16) 4,4'-bis [4- [2- (4-hydroxyphenylsulfonyl) phenoxy] butyloxy]
Diphenylsulfone (I-17) 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-2-ethyleneoxyethoxy] diphenylsulfone (I-18) 4,4'-bis [4- (4- (Hydroxyphenylsulfonyl) phenyl-1,4-phenylenebismethyleneoxy] diphenylsulfone (I-19) 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenyl-1,3-phenylenebismethyleneoxy] diphenyl Sulfone

(I-20) 4,4'-bis [4- (4-
(Hydroxyphenylsulfonyl) phenyl-1,2-phenylenebismethyleneoxy] diphenylsulfone (I-21) 2,2′-bis [4- [4- [4- (4-
(Hydroxyphenylsulfonyl) phenoxy-2-ethyleneoxyethoxy] phenylsulfonyl] phenoxy] diethyl ether (I-22) α, α'-bis [4- [4- [4- (4-
(Hydroxyphenylsulfonyl) phenyl-1,4-phenylenebismethyleneoxy] phenylsulfonyl] phenoxy] -p-xylene (I-23) α, α′-bis [4- [4- [4- (4-
(Hydroxyphenylsulfonyl) phenyl-1,3-phenylenebismethyleneoxy] phenylsulfonyl] phenoxy] -m-xylene (I-24) α, α'-bis [4- [4- [4- (4-
(Hydroxyphenylsulfonyl) phenyl-1,2-phenylenebismethyleneoxy] phenylsulfonyl] phenoxy] -o-xylene (I-25) 2,4′-bis [2- (4-hydroxyphenylsulfonyl) phenoxy-2-ethylene Oxyethoxy] diphenylsulfone (I-26) 2,4'-bis [4- (2-hydroxyphenylsulfonyl) phenoxy-2-ethyleneoxyethoxy] diphenylsulfone (I-27) 4,4'-bis [3 5-dimethyl-4-
(3,5-dimethyl-4-hydroxyphenylsulfonyl) phenoxy-2-ethyleneoxyethoxy] diphenylsulfone (I-28) 4,4'-bis [3-allyl-4- (3-
Allyl-4-hydroxyphenylsulfonyl) phenoxy-2-ethyleneoxyethoxy] diphenylsulfone (I-29) 4,4'-bis [3,5-dimethyl-4-
(3,5-dimethyl-4-hydroxyphenylsulfonyl) phenyl-1,4-phenylenebismethyleneoxy] diphenylsulfone

(I-30) 4,4'-bis [3,5-dimethyl-4- (3,5-dimethyl-4-hydroxyphenylsulfonyl) phenyl-1,3-phenylenebismethyleneoxy] diphenylsulfone ( I-31) 4,4'-Bis [3,5-dimethyl-4-
(3,5-dimethyl-4-hydroxyphenylsulfonyl) phenyl-1,2-phenylenebismethyleneoxy] diphenylsulfone (I-32) 4,4′-bis [3-allyl-4- (3-
Allyl-4-hydroxyphenylsulfonyl) 1,4-
Phenylenebismethyleneoxy] diphenylsulfone (I-33) 4,4'-bis [3-allyl-4- (3-
Allyl-4-hydroxyphenylsulfonyl) 1,3-
Phenylenebismethyleneoxy] diphenylsulfone (I-34) 4,4'-bis [3-allyl-4- (3-
Allyl-4-hydroxyphenylsulfonyl) 1,2-
[Phenylenebismethyleneoxy] diphenylsulfone (I-35) 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-2-hydroxypropyloxy] diphenylsulfone (I-36) 1,3-bis [4 -[4- [4- (4-hydroxyphenylsulfonyl) phenoxy-2-hydroxypropyloxy] phenylsulfonyl] phenoxy] -2-hydroxypropane

The compound represented by the general formula (IV) used in the present invention is disclosed in JP-A-7-149713, International Publication WO9
3/06074, WO95 / 33714, typically 1,3-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] -2-hydroxypropane 1,1-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] methane 1,2-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] ethane 1,3-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] propane 1,4- Bis [4- (4-hydroxyphenylsulfonyl) phenoxy] butane 1,5-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] pentane 1,6-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] hexane α, α'-bis [4- (4-hydroxyphenylsulfonyl) pheno [P] -p-xylene α, α'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] -m-xylene α, α'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] -o-xylene 2,2'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] diethyl ether 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] dibutyl ether 1,2-bis [4- (4 -Hydroxyphenylsulfonyl) phenoxy] ethylene 1,4-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] -2-butene. The compound represented by the general formula (I) is reacted with a 4,4'-dihydroxyphenylsulfone derivative or a 2,4'-dihydroxyphenylsulfone derivative in the presence of a basic substance by the method described in International Publication WO / 16420. It is obtained by doing.

The color developer used in the present invention contains one or two or more kinds of diphenylsulfone cross-linked compounds synthesized by the above-mentioned means. Among them, the compounds obtained by the following synthesis examples are exemplified. preferable. (Synthesis Example 1) Sodium hydroxide 1 in 21.2 g of water
After adding 6.0 g (0.4 mol) and dissolving, BPS 50.
0 g (0.2 mol) were added. Next, at 105 ° C., 14.3 g of bis (2-chloroethyl) ether (0.10 g)
Mol) and reacted at 110 ° C to 115 ° C for 5 hours. After completion of the reaction, 375 ml of water was added to the reaction solution, and 90
Stirred at C for 1 hour. After cooling to room temperature, the mixture was neutralized with 20% sulfuric acid, and the precipitated crystals were separated by filtration to obtain 39.3 g of white crystals.
88% yield from bis (2-chloroethyl) ether
Met. The composition was as follows by high performance liquid chromatography. However, the column is Mightysil
RP-18 (manufactured by Kanto Chemical), mobile phase is CH ₃ CN: H
₂ O: 1% H ₃ PO ₄ = 700: 300: 5, UV wavelength is 260 nm.

[0033]

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A = 0: retention time 1.9 minutes: area% 32.9 a = 1: retention time 2.3 minutes: area% 21.7 a = 2: retention time 2.7 minutes: area% 12. 8 a = 3: retention time 3.4 minutes: area% 8.8 a = 4: retention time 4.2 minutes: area% 5.8 a = 5: retention time 5.4 minutes: area% 3.5 a = 6: Retention time 7.0 minutes: Area% 2.2 a = 7: Retention time 9.0 minutes: Area% 1.7 a = 8: Retention time 11.8 minutes: Area% 1.3 a = 9 : Retention time 15.4 minutes: Area% 1.3

(Synthesis Examples 2 to 4) Assuming that the molar ratio of BPS and bis (2-chloroethyl) ether reacted in Synthesis Example 1 is 1.5: 1, 2.5: 1, and 3: 1, the following is obtained. A composition could be obtained. When 1.5: 1, a = 0 20.8, a = 133.0, a = 2 14.2, a = 3 7.9, a = 4 3.9 When 2.5: 1, When a = 0 49.6, a = 1 25.9, a = 2 11.4, a = 3 5.3, a = 4 2.4 3.0: 1, a = 0 56.9, a = 124.9, a = 2 9.6, a = 3 3.7, a = 4 1.3

Synthesis Example 5 10.0 g of a 48% aqueous sodium hydroxide solution and N, N'-dimethylacetamide
In 155 g of the mixed solution, 30.0 g of BPS (0.1
2 mol) was added. After melting at 80 ° C, xylene 1
Α, α'-dichloro-p-xylene dissolved in 5 g
10.5 g (0.06 mol) was slowly added dropwise. After completion of the dropwise addition, a thermal aging reaction was performed at the same temperature for 2 hours. After aging,
The crystals were poured into 900 ml of water and the precipitated crystals were separated by filtration.
The crude crystals were washed with methanol, filtered and dried to obtain 19.7 g of white crystals. When the purity was measured by high performance liquid chromatography, the main composition was as follows. α, α'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] -p-xylene 59.1% 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenyl-1,4-phenylenebis Methyleneoxy] diphenylsulfone 23.1% α, α'-bis [4- [4- [4- (4-hydroxyphenylsulfonyl) phenyl-1,4-phenylenebismethyleneoxy] phenylsulfonyl] phenoxy]-
p-Xylene 11.1% In the present invention, about 0.01 to 0.9 part of a conventionally known developer can be used in combination with 1 part of the compound of the formula (I) for the purpose of improving sensitivity. is there.

In the present invention, at least one compound represented by the general formula (II) is used as a sensitizer. In the general formula (II), R ₇ and R ₈ may be any substituents which do not impair the sensitizing effect. Examples of such substituents include a halogen atom, a halogen-substituted alkyl group and an alkyl group having 1 to 6 carbon atoms. And the like. Specific examples of the compound represented by the general formula (II) are shown below (II-
1) to (II-28), but are not limited thereto. Among them, the effect obtained when used with the developer obtained in Synthesis Example 1 is good and relatively easy to obtain (II
-1), (II-2), (II-15) or (II-1)
6) and the like are preferably used.

[0038]

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[0039]

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[0040]

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[0041]

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In the present invention, when the content of the sensitizer represented by the general formula (II) is less than 0.01 part with respect to 1 part of the developer represented by the general formula (I), the sensitizer increases. Sensitive effects are not sufficient, and when more than 2 parts are contained per part of the developer, sufficient color density cannot be obtained. Therefore, the sensitizer represented by the general formula (II) is desirably used in a proportion of 0.01 to 2 parts with respect to 1 part of the developer represented by the general formula (I).

[0043]

[Also known as Crystal Violet Lactone]

 3,3-bis (p-dimethylaminophenyl) phthalide

[Also known as malachite green lactone] <Fluoran leuco dye> 3-diethylamino-6-methylfluoran 3-diethylamino-6-methyl-7-anilinofluoran 3-diethylamino-6-methyl-7- (o , P-Dimethylanilino) fluoran 3-diethylamino-6-methyl-7-chlorofluoran 3-diethylamino-6-methyl-7- (m-trifluoromethylanilino) fluoran 3-diethylamino-6-methyl-7 -(O-chloroanilino) fluoran 3-diethylamino-6-methyl-7- (p-chloroanilino) fluoran 3-diethylamino-6-methyl-7- (o-fluoroanilino) fluoran 3-diethylamino-6-methyl-7 -(M-methylanilino) fluoran 3-diethyl Mino-6-methyl-7-n-octylanilinofluoran 3-diethylamino-6-methyl-7-n-octylaminofluoran 3-diethylamino-6-methyl-7-benzylanilinofluoran 3-diethylamino- 6-methyl-7-dibenzylanilinofluoran 3-diethylamino-6-chloro-7-methylfluoran 3-diethylamino-6-chloro-7-anilinofluoran 3-diethylamino-6-chloro-7-p -Methylanilinofluoran 3-diethylamino-6-ethoxyethyl-7-anilinofluoran 3-diethylamino-7-methylfluoran 3-diethylamino-7-chlorofluorane 3-diethylamino-7- (m-trifluoro Methylanilino) fluoran 3-diethylamino-7- (o-chloro Nilino) fluoran 3-diethylamino-7- (p-chloroanilino) fluoran 3-diethylamino-7- (o-fluoroanilino) fluoran 3-diethylamino-benzo [a] fluoran 3-diethylamino-benzo [c] fluoran 3-dibutyl Amino-6-methyl-fluoran 3-dibutylamino-6-methyl-7-anilinofluoran 3-dibutylamino-6-methyl-7- (o, p-dimethylanilino) fluoran

3-Dibutylamino-6-methyl-7-
(O-chloroanilino) fluoran 3-dibutylamino-6-methyl-7- (p-chloroanilino) fluoran 3-dibutylamino-6-methyl-7- (o-fluoroanilino) fluoran 3-dibutylamino-6-methyl -7- (m-trifluoromethylanilino) fluoran 3-dibutylamino-6-methyl-chlorofluoran 3-dibutylamino-6-ethoxyethyl-7-anilinofluoran 3-dibutylamino-6-chloro- 7-anilinofluoran 3-dibutylamino-6-methyl-7-p-methylanilinofluoran 3-dibutylamino-7- (o-chloroanilino) fluoran 3-dibutylamino-7- (o-fluoroanilino ) Fluoran 3-n-dipentylamino-6-methyl-7-anilinofluoran 3-n Dipentylamino-6-methyl-7- (p-chloroanilino) fluoran 3-n-dipentylamino-7- (m-trifluoromethylanilino) fluoran 3-n-dipentylamino-6-chloro-7-anilinofur Oran 3-n-dipentylamino-7- (p-chloroanilino) fluoran 3-pyrrolidino-6-methyl-7-anilinofluoran 3-piperidino-6-methyl-7-anilinofluoran 3- (N-methyl -N-propylamino) -6-methyl-7-anilinofluoran

3- (N-methyl-N-cyclohexylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-cyclohexylamino) -6
Methyl-7-anilinofluoran 3- (N-ethyl-N-xylamino) -6-methyl-
7- (p-chloroanilino) fluoran 3- (N-ethyl-p-toluidino) -6-methyl-
7-anilinofluoran 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-isoamylamino) -6-chloro-7-anilino Fluoran 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-isobutylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-ethoxypropylamino) -6
-Methyl-7-anilinofluoran 3-cyclohexylamino-6-chlorofluoran

2- (4-oxahexyl) -3-dimethylamino-6-methyl-7-anilinofluoran 2- (4-oxahexyl) -3-diethylamino-6
-Methyl-7-anilinofluoran 2- (4-oxahexyl) -3-dipropylamino-
6-methyl-7-anilinofluoran 2-methyl-6-p- (p-dimethylaminophenyl)
Aminoanilinofluoran 2-methoxy-6-p- (p-dimethylaminophenyl) aminoanilinofluoran 2-chloro-3-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2 -Chloro-6-p- (p-dimethylaminophenyl)
Aminoanilinofluoran 2-nitro-6-p- (p-diethylaminophenyl)
Aminoanilinofluoran 2-amino-6-p- (p-diethylaminophenyl)
Aminoanilinofluoran 2-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluoran 2-phenyl-6-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2- Benzyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2-hydroxy-6-p- (p-phenylaminophenyl) aminoanilinofluoran 3-methyl-6-p- (p-dimethyl Aminophenyl)
Aminoanilinofluoran 3-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluoran 3-diethylamino-6-p- (p-dibutylaminophenyl) aminoanilinofluoran 2,4-dimethyl- 6-[(4-dimethylamino) anilino] -fluoran

<Fluorene Leuco Dye>3,6,6'-Tris (dimethylamino) spiro [fluorene-9,3'-phthalide] 3,6,6'-Tris (diethylamino) spiro [fluorene-9,3 '-Phthalide] <Divinyl leuco dye> 3,3-bis- [2- (p-dimethylaminophenyl)
-2- (p-methoxyphenyl) ethenyl] -4,5
6,7-tetrabromophthalide 3,3-bis- [2- (p-dimethylaminophenyl)
-2- (p-methoxyphenyl) ethenyl] -4,5
6,7-tetrachlorophthalide 3,3-bis- [1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl] -4,5,6,7-tetrabromophthalide 3,3- Bis- [1- (4-methoxyphenyl) -1-
(4-pyrrolidinophenyl) ethylene-2-yl]-
4,5,6,7-tetrachlorophthalide <Others> 3- (4-diethylamino-2-ethoxyphenyl)-
3- (1-ethyl-2-methylindol-3-yl)
-4-azaphthalide 3- (4-diethylamino-2-ethoxyphenyl)-
3- (1-octyl-2-methylindol-3-yl) -4-azaphthalide 3- (4-cyclohexylethylamino-2-methoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) ) -4-Azaphthalide 3,3-bis (1-ethyl-2-methylindole-3
-Yl) phthalide 3,6-bis (diethylamino) fluoran-γ- (3
'-Nitro) anilinolactam 3,6-bis (diethylamino) fluoran-γ- (4
'-Nitro) anilinolactam 1,1-bis- [2', 2 ', 2 ", 2" -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,
2-dinitrileethane 1,1-bis- [2 ', 2', 2 ", 2" -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2-
β-naphthoylethane 1,1-bis- [2 ′, 2 ′, 2 ″, 2 ″ -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,
2-Diacetylethane bis- [2,2,2 ', 2'-tetrakis- (p-dimethylaminophenyl) -ethenyl] -methylmalonic acid dimethyl ester

In the present invention, a conventionally known color developing agent which forms a colorless or light-colored basic dye can be used in combination within a range not to impair the desired effect on the above-mentioned problem. However, it is desirable to add a very small amount of the compound.
It is about 01 to 0.9 parts. Examples of such a developer include JP-A-3-207688 and JP-A-5-2436.
No. 6, such as bisphenol A, 4-hydroxybenzoic acid esters, 4-hydroxyphthalic acid diesters, phthalic acid monoesters, bis- (hydroxyphenyl) sulfides, 4-hydroxyphenylaryl sulfones, 4-hydroxyphenylarylsulfonates, 1,3-di [2- (hydroxyphenyl)
-2-propyl] -benzenes, 4-hydroxybenzoyloxybenzoic acid esters, and bisphenolsulfones. In the present invention, conventionally known sensitizers can be used as long as the desired effects on the above-mentioned objects are not impaired. Examples of such a sensitizer include fatty acid amides such as stearic acid amide and palmitic acid amide;
Ethylene bisamide, montanic acid wax, polyethylene wax, 1,2-di- (3-methylphenoxy) ethane, p-benzylbiphenyl, β-benzyloxynaphthalene, 4-biphenyl-p-tolyl ether, m-
Terphenyl, 1,2-diphenoxyethane, dibenzyl oxalate, di (p-chlorobenzyl) oxalate, di (p-methylbenzyl) oxalate, dibenzyl terephthalate, benzyl p-benzyloxybenzoate, di-p -Tolyl carbonate, phenyl-α-naphthyl carbonate, 1,4-diethoxynaphthalene, 1-hydroxy-
2-naphthoic acid phenyl ester, o-xylene-bis- (phenyl ether), 4- (m-methylphenoxymethyl) biphenyl, 4,4'-ethylenedioxy-bis-benzoic acid dibenzyl ester, dibenzoyloxymethane , 1,2-di (3-methylphenoxy) ethylene, bis [2- (4-methoxy-phenoxy) ethyl]
Examples include ether, methyl p-nitrobenzoate, and phenyl p-toluenesulfonate, but are not particularly limited thereto. These sensitizers may be used alone or in combination of two or more.

As the binder used in the present invention, completely saponified polyvinyl alcohol having a degree of polymerization of 200 to 1900, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, butyral-modified polyvinyl alcohol Alcohol, other modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer and cellulose derivatives such as ethyl cellulose, acetyl cellulose, polyvinyl chloride, polyacetic acid vinyl,
Examples thereof include polyacrylamide, polyacrylate, polyvinylbutylalal, polystyrene and copolymers thereof, polyamide resin, silicone resin, petroleum resin, terpene resin, ketone resin, and cumaro resin. These macromolecules are water, alcohol, ketone,
In addition to dissolving in solvents such as esters and hydrocarbons,
It is used in a state of being emulsified or dispersed in water or another medium in the form of a paste, and may be used in combination depending on required quality.

In the present invention, 4,4'-butylidene (6-t-butyl-3) is used as an image stabilizer which exhibits an oil resistance effect of a recorded image, as long as the desired effect on the above-mentioned object is not impaired. -Methylphenol) 2,2'-di-t-butyl-5,5'-dimethyl-4,
4'-sulfonyldiphenol 1,1,3-tris (2-methyl-4-hydroxy-5
-Cyclohexylphenyl) butane 1,1,3-tris (2-methyl-4-hydroxy-5
-T-butylphenyl) butane and the like can also be added.

The filler used in the present invention includes silica,
Examples include inorganic or organic fillers such as calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, talc, titanium oxide, and aluminum hydroxide. In addition, release agents such as fatty acid metal salts, lubricants such as waxes, benzophenone-based and triazole-based ultraviolet absorbers, waterproofing agents such as glyoxal, dispersants, defoamers, antioxidants,
A fluorescent dye or the like can be used. The amounts of the developer and dye used in the heat-sensitive recording medium of the present invention, and the types and amounts of other various components are determined according to required performance and recording suitability, and are not particularly limited. 0.1 to 2 parts of a basic colorless dye, 1 part of the developer represented by (I), and 0.01 part of the compound represented by the formula (II)
2 to 2 parts and 0.5 to 4 parts of filler are used, and the binder is suitably 5 to 25% of the total solid content.

The desired heat-sensitive recording sheet can be obtained by applying the coating solution having the above composition to any support such as paper, recycled paper, synthetic paper, film, plastic and the like. Further, an overcoat layer of a polymer substance or the like can be provided on the thermosensitive coloring layer for the purpose of enhancing the storage stability. The aforementioned organic developer, basic colorless dye and optionally added materials are pulverized to a particle size of several microns or less by a pulverizer such as a ball mill, an attritor, a sand glider or an appropriate emulsifier, and a binder. And various additive materials are added according to the purpose to form a coating liquid. further,
An undercoat layer of a filler-containing polymer substance or the like can be provided below the heat-sensitive layer for the purpose of increasing color development sensitivity.

[0054]

EXAMPLES The thermosensitive recording medium of the present invention will be described below with reference to examples. In the description, parts and% represent parts by weight and% by weight, respectively, unless otherwise specified. [Examples 1 to 4] In Examples 1 to 4, the compounds (I-1), (I-2) and (I) were used as developers in the thermosensitive recording medium of the present invention.
-13) or (I-17), 3 as a basic colorless dye
-Dibutylamino-6-methyl-7-anilinofluoran (ODB-2) and an example using compound (II-1) as a sensitizer. A developer dispersion (solution A), a basic colorless dye dispersion (solution B) and a sensitizer dispersion (C)
Liquids) with an average particle size of 1 using a sand grinder.
Wet grinding was performed to a micron. Liquid A (Developer dispersion liquid) Developer 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts Water 11.2 parts Liquid B (Basic colorless dye dispersion liquid) 3-dibutylamino-6-methyl-7 -Anilinofluoran (ODB-2) 2.0 parts 10% aqueous solution of polyvinyl alcohol 4.6 parts Water 2.6 parts Liquid C (sensitizer dispersion) Compound (II-1) 4.0 parts 10% polyvinyl alcohol Aqueous alcohol solution 18.8 parts Water 11.2 parts Next, the dispersion was mixed and stirred at the following ratio to prepare a coating liquid. Liquid A (developer dispersion liquid) 36.0 parts Liquid B (basic colorless dye [ODB-2] dispersion liquid) 9.2 parts Liquid C (sensitizer [compound (II-1)] dispersion liquid) 34 0.0 parts Kaolin clay (50% dispersion) 12.0% After applying each of the above coating liquids to one side of a base paper of 50 g / m ² , drying was carried out, and the sheet was smoothed with a super calendar at a smoothness of 500 to 600. Seconds to obtain a thermosensitive recording medium having a coating amount of 6.0 g / m ² .

[Examples 5 to 9] In Examples 5 to 9, the compounds obtained in Synthesis Examples 1 to 5 were used as developers, ODB-2 was used as a basic colorless dye, and the compound (II-1) was used as a sensitizer. )
This is an example using. A basic colorless dye dispersion and a sensitizer dispersion were treated in the same manner as in Examples 1 to 4. Synthesis Example 1
The developer dispersion liquids (D liquids) obtained in Nos. 1 to 5 were separately wet-ground by a sand grinder until the average particle diameter became 1 μm. Liquid D (Developer dispersion obtained by Synthesis Examples 1 to 5) 6.0 parts of the above developer 18.8 parts of a 10% aqueous polyvinyl alcohol solution 11.2 parts of water Next, the dispersion was mixed at the following ratio. The mixture was stirred to prepare a coating solution. Liquid D (Developer dispersion obtained by Synthesis Examples 1 to 5) 36.0 parts Liquid B (basic colorless dye [ODB-2] dispersion) 9.2 parts Liquid C (sensitizer [compound ( II-1)] Dispersion) 34.0 parts Kaolin clay (50% dispersion) 12.0 parts After applying each of the above coating solutions to one side of a 50 g / m ² base paper, drying is performed, and the sheet is dried. Processing was performed with a super calendar so that the smoothness became 500 to 600 seconds, to obtain a heat-sensitive recording material having a coating amount of 6.0 g / m ² .

Examples 10 to 12 Examples 10 to 12
Is an example using the compound obtained in Synthesis Example 1 as a developer, the following basic colorless dye other than ODB-2 as a basic colorless dye, and the compound (II-1) as a sensitizer. (Basic colorless dye) ODB: 3-diethylamino-6-methyl-7-anilinofluoran S-205: 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluoran Black -100: 3-diethylamino-7- (m-
Trifluoromethylanilino) fluorane The developer dispersion obtained in Synthesis Example 1 and the sensitizer dispersion of compound (II-1) were treated in the same manner as in Examples 1 to 4.
The basic colorless dye dispersions other than ODB-2 (solution E) were separately wet-ground using a sand grinder until the average particle size became 1 μm. Solution E (Basic colorless dye dispersion other than ODB-2) The above basic colorless dye 2.0 parts 10% aqueous polyvinyl alcohol solution 4.6 parts Water 2.6 parts Then, the dispersion liquid is mixed and stirred at the following ratio. Then, a coating solution was prepared. Liquid D (Developer dispersion obtained in Synthesis Example 1) 36.0 parts Liquid E (basic colorless dye dispersion other than ODB-2) 9.2 parts Liquid C (sensitizer [compound (II- 1)] Dispersion) 34.0 parts Kaolin clay (50% dispersion) 12.0 parts After applying each of the above coating liquids to one side of a base paper of 50 g / m ² , drying was performed, and this sheet was supercalendered. To obtain a heat-sensitive recording material having a coating amount of 6.0 g / m ² .

Embodiments 13 to 18 Embodiments 13 to 18
Is a compound obtained in Synthesis Example 1 as a developer, ODB-2 as a basic colorless dye, and a compound (II-
2), (II-6), (II-8), (II-10), (II-
This is an example using (15) and (II-16). Example 1
The developer dispersion and the ODB-2 dispersion of the compound obtained in Synthesis Example 1 were treated in the same manner as in Examples 4 to 4 to obtain a compound (II-2)
To (II-16) were obtained in the same manner as in the compound (II-1) to obtain a dispersion liquid (F liquid). Next, the dispersion liquid was mixed and stirred at the following ratio to prepare a coating liquid. Liquid D (developer dispersion liquid obtained in Synthesis Example 1) 36.0 parts Liquid B (basic colorless dye [ODB-2] dispersion liquid) 9.2 parts Liquid F (sensitizer dispersion liquid) 0 parts Kaolin clay (50% dispersion) 12.0 parts After applying each of the above coating liquids to one side of a base paper of 50 g / m ² , drying is performed, and the sheet is smoothed with a super calendar at a smoothness of 500 to 600 seconds. To obtain a thermosensitive recording medium having a coating amount of 6.0 g / m ² .

Example 19 In Example 19, the compound obtained in Synthesis Example 1 was used as a developer, and O was used as a basic colorless dye.
DB-2 and S-205, compounds (II-
This is an example using 1). In the same manner as in Examples 1 to 4,
Developer dispersion of the compound obtained in Synthesis Example 1, ODB-2
The dispersion, the S-205 dispersion, and the sensitizer dispersion of the compound (II-1) were treated. Next, the dispersion liquid was mixed and stirred at the following ratio to prepare a coating liquid. Liquid D (Developer dispersion obtained in Synthesis Example 1) 36.0 parts Liquid B (basic colorless dye [ODB-2] dispersion) 4.6 parts Liquid E (basic colorless dye [S-205] ] Dispersion) 4.6 parts Solution C (sensitizer [compound (II-1)] dispersion) 34.0 parts Kaolin clay (50% dispersion) 12.0 parts 50 g / m ^{2 of} each of the above coating solutions Was coated on one side of the base paper and dried, and this sheet was treated with a super calender so that the smoothness became 500 to 600 seconds, to obtain a thermosensitive recording material having a coating amount of 6.0 g / m ² .

Comparative Example 1 The same operation as in Example 5 was performed. However, the dispersion C was not mixed in the formation of the coloring layer. Comparative Example 2 The same operation as in Example 5 was performed. However, in preparing dispersion C, p was used instead of compound (II-1).
-Benzylbiphenyl (PBB) was used. [Comparative Examples 3 and 4] Comparative Examples 3 and 4 are examples in which the developer of Example 5 was replaced with the following developer. Comparative Example 3: 4,4'-isopropylidene diphenol (alias: BPA) Comparative Example 4: 4-hydroxy-4'-isopropylidene diphenyl sulfone (alias: D-8) <Evaluation of thermosensitive recording medium> The recording medium was printed with an applied energy of 0.30 and 0.38 mj / dot using TH-PMD (a thermal recording paper printing tester manufactured by Okura Electric Co., Ltd., equipped with a thermal head manufactured by Kyocera). The recording density of the recording section was measured with a Macbeth densitometer (RD-914, using an amber filter) (see Tables 1 and 2). <Evaluation of plasticizer resistance> A vinyl chloride wrap (Hi-wrap KMA manufactured by Mitsui Toatsu) was wrapped around a paper tube in a single layer, and the thermosensitive recording medium recorded by the printer (0.38 mj / dot) was pasted thereon, and further After a triple wrap of PVC wrap was left at 40 ° C. for 72 hours, the Macbeth density of the image area was measured (see Tables 1 and 2).

[0060]

[Table 1]

[0061]

[Table 2]

As is clear from Tables 1 and 2,
When the compound represented by the general formula (I) is used as a developer, high recording sensitivity is exhibited when the compound represented by the general formula (II) is used in combination. On the other hand, in Comparative Example 2 using another sensitizer,
Sufficient color-forming ability was not obtained, indicating that the compound represented by the general formula (II) has a remarkable sensitizing effect. The deterioration of the recorded image due to the contact with the plasticizer contained in the vinyl chloride wrap, which was observed in Comparative Examples 3 and 4 using other developers, was caused by the compound represented by the general formula (I). When you say, it is hardly seen.

[0063]

The heat-sensitive recording material of the present invention comprises a compound represented by the general formula (II) when the diphenylsulfone cross-linked compound represented by the general formula (I) is used as a developer. By containing as a sensitizer, the compound represented by the general formula (I)
While maintaining image stability such as plasticizer property, which is a feature of the compound represented by the formula, the color development sensitivity is high and the recorded image is good. Therefore, a clear image with high sensitivity can be obtained even with a small amount of energy, so that it is suitable for high-speed printing and devices with small applied energy, and has high practicality.

Continued on the front page (72) Inventor Kaoru Hamada 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo Japan Paper Manufacturing Co., Ltd. (72) Inventor Yoshihide Kimura 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo Japan Paper Machinery Inside the Product Development Laboratory Co., Ltd. (72) Inventor Tomoaki Nagai 5-2-1-1, Oji, Kita-ku, Tokyo Nippon Paper Industries Incorporated (72) Inventor Yutaka Wakita 2-2-1 Nankocho, Ishinomaki-shi, Miyagi Japan Japan F term in the Ishinomaki Mill (reference) 2H026 AA07 BB01 BB24 BB28 DD02 DD12 DD17 DD45 DD53

Claims (1)

[Claims] 1. A thermosensitive recording medium comprising a support having thereon a heat-sensitive recording layer containing a colorless or light-colored basic colorless dye and an organic color developer as main components, wherein the heat-sensitive recording layer comprises an organic color developer. A diphenylsulfone cross-linkable compound represented by the following general formula (I), and a compound represented by the following general formula (II) as a sensitizer is added in an amount of 0.0
A thermosensitive recording medium containing at least one kind in a proportion of 1 to 2 parts. Embedded image [In the formula, X and Y each represent a hydrocarbon group which may be different from each other and may have a linear or branched saturated or unsaturated carbon atom having 1 to 12 carbon atoms, or may have an ether bond; Or Or (R represents a methylene group or an ethylene group, T represents a hydrogen atom or a C ₁ -C ₄ alkyl group). R _{1 to} R ₆ are each independently a halogen atom, a C _{1 to} C ₆ alkyl group,
Shows an alkenyl group. Also, m, n, p, q, r, and t are 0
Represents an integer from to 4, and when it is 2 or more, R _{1 to} R ₆ may be different from each other. a represents an integer of 1 to 10. [Formula 4] (In the formula, R ₇ represents a halogen atom or an alkyl group having 1 to 6 carbon atoms, and u represents an integer of 0 to 2.
₈ is unsubstituted or substituted phenyl group, or
Represents a benzyl group, and the substituent represents a halogen atom, a halogen-substituted alkyl group or an alkyl group having 1 to 6 carbon atoms. )