JP2001287464A - Heat sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sensitive recording material excellent in the color developing speed of the recording material, the preservability of a record, the holding of sensitizing effects, the pollution resistance of a thermal head or the like. SOLUTION: In the heat sensitive recording material, in which a color developing reaction between an electron donable leuco dye and an acid developer, which forms color in the electron donable leuco dye, the heat sensitive recording material includes a cyclic imide compound represented with formula (1) or (2), wherein n represent 2 or 3, R1 represents an alkyl group with a substitute or an aryl group allowable with a substitute, R2 represents on an alkylene group allowable with a substitute in a chain or a bivalent aromatic hydrocarbon ring group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly, to a heat-sensitive recording material utilizing a color-forming reaction between an electron-donating leuco dye and an acidic developer for forming the same.

[0002]

2. Description of the Related Art A color-forming reaction between an electron-donating leuco dye typified by crystal violet lactone and an electron-accepting or acidic developer represented by a phenolic compound or a nucleus-substituted zinc salicylate is known. As recording materials used, pressure-sensitive recording materials and heat-sensitive recording materials have been put into practical use and are widely used. Thermal recording materials
By heating and melting a crystalline electron-donating leuco dye and a crystalline acidic developer with a hot pen or a thermal head, a mixing reaction occurs between the two and a colored recorded image is obtained. Have been.

Here, a third substance having a relatively low melting point, called a sensitizer, is usually added for the purpose of improving the recording speed by reducing the amount of thermal energy applied to the thermosensitive recording material. is there.

As sensitizers, stearoylamide, 2
Benzyloxynaphthalene, 1,2-diphenoxyethane, 1,2-di (3-tolyloxy) ethane, 4-benzylbiphenyl, di (4-methylbenzyl) oxalate, 4- (4-tolyloxy) biphenyl and acetolui Jid and the like are known and are already in practical use.

[0005] These techniques are disclosed in Japanese Patent Application Laid-Open No. 58-8 / 1983.
No. 7094, JP-A-59-9092, JP-A-60-56588, JP-A-60-82382, JP-A-64-1583, JP-A-2-9683
And JP-A-3-36034.

[0006]

When recording is performed by heating and melting an electron-donating leuco dye and an acidic developer to form a color, if a sensitizer is present, the applied energy required is small, and Can be recorded. However, the sensitizers conventionally used could not solve some of the following disadvantages.

One disadvantage is that records obtained using a sensitizer have poorer storability than those obtained at higher temperatures without using the sensitizer. The storability of the record means that when the record is stored at a relatively high temperature, when the record is stored in contact with a film containing a plasticizer, when the record is stored under high humidity, or when hand cream is used. This refers to the resistance to fading of prints when a record contaminated with oil or fat is stored.

A second disadvantage is that when a developer having a relatively high melting point is used, the first effect of the sensitizer, that is, a reduction in applied energy for obtaining recording, cannot be seen.

[0009] The third disadvantage is due to the volatility of the sensitizer,
After exposing the recording material to air at high temperature for a long time, the recording material loses the sensitizing effect, or when such a thermosensitive recording material is used for facsimile, etc., the sensitizer volatilizes due to heating of the thermal head, and The sensitizer solidifies and accumulates in the cooling part immediately after the head, causing a trouble called head scum,
A phenomenon occurs in which the sliding property between the thermal recording material and the thermal head is hindered and the adhesion between the thermal head and the surface of the thermal recording material is hindered.

An object of the present invention is to solve the above-mentioned drawbacks by using a novel sensitizer, and to provide a heat-sensitive material which is excellent in the color-forming speed of a recording material, the preservability of a record, the retention of a sensitizing effect and the stain resistance of a thermal head. To provide a recording material.

[0011]

According to the present invention, there is provided a heat-sensitive recording material utilizing a color-forming reaction between an electron-donating leuco dye and an acidic developer for forming the same. There is provided a heat-sensitive recording material characterized by containing the cyclic imide compound represented by 2).

[0012]

Embedded image

In the formula, n represents 2 or 3, and R ¹ represents an alkyl group having a substituent or an aryl group which may have a substituent.

[0014]

Embedded image

In the formula, n represents 2 or 3, and R ² represents an alkylene group which may have a substituent in the chain, or a divalent aromatic hydrocarbon ring group.

In the present invention, the alkyl group includes a methyl group, an ethyl group and a propyl group, and the aryl group includes a phenyl group, a tolyl group and a xylyl group. Ethylene group,
1,3-propylene group, 1,4-butylene group and the like, and divalent aromatic hydrocarbon ring groups include o- and m-
And p-xylylene.

The substituents which these may have include aryl groups such as phenyl, chlorobenzene, tolyl, benzoxy and naphthoxy, and alkoxy groups such as methoxy and ethoxy.

[0018]

Embodiments of the present invention will be described below in detail.

The heat-sensitive recording material according to the present invention contains a cyclic imide compound represented by the general formula (1) or (2) as a so-called sensitizer, and has sufficiently solved the object of the present invention. It is.

Among the cyclic imide compounds represented by the general formula (1), N-benzylsuccinimide, N- (4-chlorobenzyl) succinimide, N- (4-methylbenzyl) are preferable for the purpose of the present invention. ) Succinimide, N-phenethyl succinimide, N- {2- (2-
Naphthoxy) ethyl @ succinimide, N- (2-benzoxyethyl) succinimide, N- {2- (4-chlorobenzoxy) ethyl} succinimide, N- {2-
(4-methylbenzoxy) ethyl @ succinimide, N
-(3-phenoxypropyl) succinimide, N-
{3- (4-tolyloxy) propyl} succinimide,
N- {3- (2-naphthoxy) propyl} succinimide, N- (3-benzoxypropyl) succinimide,
N-phenylsuccinimide, N- (2-tolyl) succinimide, N- (3-tolyl) succinimide, N-
(4-tolyl) succinimide, N- (2,4-xylyl) succinimide, N- (2,5-xylyl) succinimide, N- (3,4-xylyl) succinimide,
N- (4-methoxyphenyl) succinimide, N-
(4-ethoxyphenyl) succinimide, N- (4-
(Chlorobenzyl) glutarimide, N- (4-methylbenzyl) glutarimide, N-phenethylglutarimide, N- {2- (2-naphthoxy) ethyl} glutarimide, N- {3- (2-naphthoxy) propyl} Glutarimide, N- (3-benzoxypropyl) glutarimide, N- {3- (4-methylbenzoxy) propyl}
Glutarimide, N-phenylglutarimide, N-
(4-tolyl) glutarimide, N- (3-methoxyphenyl) glutarimide, N- (4-methoxyphenyl) glutarimide and N- (4-ethoxyphenyl)
Glutarimide and the like can be mentioned, but according to the definition of the general formula (1) of the present invention, further various kinds of cyclic imide compounds can be easily inferred.

Among the cyclic imide compounds represented by the general formula (2), those preferred for the purpose of the present invention include N, N '
-(1,2-ethylene) bissuccinimide, N, N '
-(1,3-propylene) bissuccinimide, N,
N ′-(1,4-butylene) bissuccinimide, N,
N ′-(1,6-hexylene) bissuccinimide,
N, N '-{1,5- (3-oxa) pentylene} bissuccinimide, N, N'-{1,7- (4-oxa)
Heptylene @ bissuccinimide, N, N '-(orthoxylylene) bissuccinimide, N, N'-(metaxylylene) bissuccinimide, N, N '-(paraxylylene) bissuccinimide, N, N'-(1,2- Ethylene) bisglutarimide, N, N ′-(1,3-propylene) bisglutarimide, N, N ′-(1,4-
Butylene) bisglutarimide, N, N '-(1,6-
Hexylene) bisglutarimide, N, N '-｛1,5
-(3-oxapentylene)｝ bisglutarimide,
N, N '-{1,7- (4-oxaheptylene)} bisglutarimide, N, N'-(orthoxylylene) bisglutarimide, N, N '-(metaxylylene) bisglutarimide and N, N' -(Paraxylylene) glutarimide and the like.

Formula (1) which is more preferable for the purpose of the present invention
Alternatively, examples of the cyclic imide compound represented by the general formula (2) include N-benzylsuccinimide, N- (4-methylbenzyl) succinimide, N-phenethylsuccinimide, N- {2- (2-naphthoxy) ethyl} succinimide, -(3-phenoxypropyl) succinimide, N- {3- (4-tolyloxy) propyl} succinimide, N-phenylsuccinimide, N- (3-tolyl) succinimide, N- (4-tolyl) succinimide, N- (2 , 4-Xylyl) succinimide, N-phenylglutarimide, N- (4-tolyl) glutarimide, N, N '-(1,4-butylene) bissuccinimide and N, N'-(1,6-hexylene) And succinimide.

The electron-donating leuco dye used in the present invention includes crystal violet lactone, 3,3
-Bis (4-dimethylaminophenyl) phthalide, 3-
(4-dimethylaminophenyl) -3- (1,2-dimethylaminoindol-3-yl) phthalide, 2-anilino-3-methyl-6-diethylaminofluoran, 2
-Anilino-3-methyl-6- (methylcyclohexylamino) fluoran, 2-anilino-3-methyl-6-
(Ethyl isopentylamino) fluoran, 2-anilino-3-methyl-6-dibutylaminofluoran, 2-
(4-chloroanilino) -3-methyl-6-diethylaminofluoran, 2- (4-fluoroanilino) -3-
Methyl-6-dibutylaminofluoran, 2-anilino-3-methyl-6- (4-toluidinoethylamino) fluoran, 2- (2-chloroanilino) -6-dibutylaminofluoran, 2- (2- Fluoroanilino) -6
-Diethylaminofluoran, 2- (2-fluoroanilino) -6-dibutylaminofluoran, 2-anilino-3-methyl-6-piperidinofluoran, 2- (3-
(Trifluoromethylanilino) -6-diethylaminofluoran, 2- (2-ethoxyethylamino) -3-chloro-6-diethylaminofluoran, 2-anilino-
3-chloro-6-diethylaminofluoran, 2-chloro-3-methyl-6-dimethylaminofluoran, 3-
Methyl-3-spirodinaphthopyran, 3-methylnaphth (3-methoxybenzo) spirolan, 1,3,3-trimethyl-6'-nitro-8'-methoxyspiro (indoline-2,2'-benzopyran) and 1 , 3,3-trimethyl-6-nitrospiro (indoline-2,2'-benzopyran) and the like.

Examples of the acidic developer used in the present invention include, in addition to the nuclear-substituted salicylic acid derivative, 2,2-bis (4
-Hydroxyphenyl) propane (alias: bisphenol-A), 2,2-bis (4-hydroxyphenyl)-
4-methylpentane, 4,4'-dihydroxydiphenylsulfone (alias: bisphenol-S), 2,4'-
Dihydroxydiphenylsulfone, 3,3′-dimethyl-4,4′-dihydroxydiphenylsulfone, 3,
3'-diallyl-4,4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 2,4-di (phenylsulfonyl) phenol, 2,4-di (phenylsulfonyl) -5-methyl Examples include compounds in which phenol and 4,4′-dihydroxydiphenyl sulfone are bimolecularly ether-linked with an alkylene group or an alkylene group having a substituent in the chain.

Other sensitizers that can be used simultaneously in the heat-sensitive recording material of the present invention include stearoylamide, 2-benzyloxynaphthalene, 1,2-diphenoxyethane,
Examples thereof include 2-di (3-tolyloxy) ethane, di (4-methylbenzyl) oxalate, 4- (4-tolyloxy) biphenyl, acetanilide, acetotoluidide, and acetoanisidide.

The compounding weight ratio of leuco dye: color developer: sensitizer in the heat-sensitive recording material of the present invention varies depending on the characteristics of each compound.
600, preferably 100-400, sensitizer 50-80
0, preferably 100 to 400.

In order to improve the preservability of the record, a polyhydric phenol compound, an epoxy compound, an anthranilic acid, a metal salt of an anthranilic acid derivative and a cyclic phosphorus compound may be used. Can be applied.

These sensitizers, leuco dyes and color developers used in the heat-sensitive recording material are usually finely pulverized in water with a medium such as a ball mill or a sand grinder, and then mixed. Fillers, etc.
A paint is prepared by adding and mixing a lubricant such as waxes, an aqueous adhesive and an antifoaming agent. This paint is usually applied on a support such as paper or film and dried to finish the heat-sensitive recording material.

[0029]

EXAMPLES In order to further clarify the present invention, specific examples and comparative examples will be described below. In addition, "part" in an Example shows a weight part.

(Example 1) <Preparation of solution A> 2-anilino-3-methyl-6-dibutylaminofluoran 10 parts N-benzylsuccinimide 20 parts Methylcellulose 5% aqueous solution 15 parts Water 120 parts

This composition was pulverized with a sand grinder so as to have an average particle diameter of 1 μm to obtain a liquid A.

<Preparation of Solution B> 4,4'-dihydroxydiphenyl sulfone 30 parts Methyl cellulose 5% aqueous solution 30 parts Water 70 parts

This composition was pulverized with a sand grinder so as to have an average particle diameter of 1 μm to obtain a liquid B.

<Preparation of Thermosensitive Recording Material by Forming Recording Layer> 175 parts of solution A, 130 parts of solution B, calcium carbonate pigment 3
0 parts, 150 parts of a 20% oxidized starch aqueous solution and 55 parts of water were mixed to prepare a paint. The coating material obtained on 50 g / m ² base paper was applied and dried so that the coating amount after drying was 7.5 g / m ² , to prepare a heat-sensitive recording material.

(Example 2) 4,4 used in Example 1
-2,4'- in place of dihydroxydiphenylsulfone
A heat-sensitive recording material was prepared in exactly the same manner as in Example 1 except that dihydroxydiphenyl sulfone was used.

(Example 3) 4,4 'used in Example 1
A heat-sensitive recording material was prepared in exactly the same manner as in Example 1 except that 4-hydroxy-4'-isopropoxydiphenylsulfone was used instead of -dihydroxydiphenylsulfone.

(Example 4) 4,4 'used in Example 1
A heat-sensitive recording material was prepared in exactly the same manner as in Example 1 except that 2,4-di (phenylsulfonyl) -5-methylphenol was used instead of -dihydroxydiphenylsulfone.

Example 5 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that N- (4-methylbenzyl) succinimide was used instead of N-benzylsuccinimide used in Example 1. did.

(Example 6) 4,4 'used in Example 5
-2,4'- in place of dihydroxydiphenylsulfone
A heat-sensitive recording material was prepared in exactly the same manner as in Example 5 except that dihydroxydiphenyl sulfone was used.

(Example 7) 4,4 'used in Example 5
A heat-sensitive recording material was prepared in exactly the same manner as in Example 5, except that 4-hydroxy-4'-isopropoxydiphenylsulfone was used instead of -dihydroxydiphenylsulfone.

(Example 8) 4,4 'used in Example 5
A heat-sensitive recording material was prepared in exactly the same manner as in Example 5 except that 2,4-di (phenylsulfonyl) -5-methylphenol was used instead of -dihydroxydiphenylsulfone.

Example 9 A thermosensitive recording material was prepared in exactly the same manner as in Example 1 except that N-phenethylsuccinimide was used instead of N-benzylsuccinimide used in Example 1.

Example 10 The procedure of Example 4 was repeated, except that N-phenethylsuccinimide was used instead of N-benzylsuccinimide used in Example 4.
A heat-sensitive recording material was prepared.

(Example 11) Thermal recording was performed in exactly the same manner as in Example 1 except that N- {2- (2-naphthoxy) ethyl} succinimide was used instead of N-benzylsuccinimide used in Example 1. Materials were prepared.

Example 12 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that N- (3-phenoxypropyl) succinimide was used in place of N-benzylsuccinimide used in Example 1. did.

Example 13 The procedure of Example 1 was repeated except that N- {3- (4-tolyloxy) propyl} succinimide was used instead of N-benzylsuccinimide used in Example 1. A recording material was prepared.

Example 14 The procedure of Example 1 was repeated, except that N-phenylsuccinimide was used instead of N-benzylsuccinimide used in Example 1.
A heat-sensitive recording material was prepared.

Example 15 A heat-sensitive recording material was prepared in exactly the same manner as in Example 1 except that N- (3-tolyl) succinimide was used in place of N-benzylsuccinimide used in Example 1. .

Example 16 A heat-sensitive recording material was prepared in exactly the same manner as in Example 1 except that N- (4-tolyl) succinimide was used instead of N-benzylsuccinimide used in Example 1. .

Example 17 A heat-sensitive recording material was prepared in exactly the same manner as in Example 1 except that N-phenylglutarimide was used in place of N-benzylsuccinimide used in Example 1.

Example 18 Instead of 20 parts of N-benzylsuccinimide used in Example 1, 10 parts of N-benzylsuccinimide and N, N '-(1,4-butylene)
Example 1 except that 10 parts bissuccinimide was used.
A heat-sensitive recording material was prepared in exactly the same manner as described above.

Example 19 The procedure of Example 4 was repeated, except that N, N ′-(1,6-hexylene) bissuccinimide was used instead of N-benzylsuccinimide used in Example 4. A heat-sensitive recording material was prepared.

Example 20 The procedure of Example 3 was repeated, except that 10 parts of N-benzylsuccinimide and 10 parts of 1,2-di (3-tolyloxy) ethane were used instead of 20 parts of N-benzylsuccinimide used in Example 3. A heat-sensitive recording material was prepared in exactly the same manner as in Example 3.

Example 21 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that N- (2,4-xylyl) succinimide was used instead of N-benzylsuccinimide used in Example 1. Prepared.

Comparative Example 1 Example 1 was repeated except that the N-benzylsuccinimide used in Example 1 was not used.
A heat-sensitive recording material was prepared in exactly the same manner as described above.

Comparative Example 2 A thermosensitive recording material was prepared in exactly the same manner as in Example 1 except that stearoylamide was used in place of N-benzylsuccinimide used in Example 1.

Comparative Example 3 A heat-sensitive recording material was prepared in exactly the same manner as in Example 1 except that 2-benzyloxynaphthalene was used in place of N-benzylsuccinimide used in Example 1.

Comparative Example 4 A heat-sensitive recording material was prepared in exactly the same manner as in Example 1 except that 1,2-diphenoxyethane was used in place of N-benzylsuccinimide used in Example 1. .

(Comparative Example 5) Thermal recording was carried out in exactly the same manner as in Example 1 except that 1,2-di (3-toloxy) ethane was used instead of N-benzylsuccinimide used in Example 1. Materials were prepared.

Comparative Example 6 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that di (4-methylbenzyl) oxalate was used in place of N-benzylsuccinimide used in Example 1. did.

Comparative Example 7 A heat-sensitive recording material was prepared in exactly the same manner as in Example 1 except that N-benzylphthalimide was used instead of N-benzylsuccinimide used in Example 1.

Comparative Example 8 A heat-sensitive recording material was prepared in exactly the same manner as in Example 1 except that acetotoluidide was used in place of N-benzylsuccinimide used in Example 1.

<Evaluation of Examples and Comparative Examples><Evaluation 1 Evaluation of Coloring Sensitivity (Coloring Speed)> Examples 1 and 2
1 and the thermal recording materials prepared in Comparative Examples 1 to 8 were printed using a thermal printer made by Okura Electric Co., Ltd. with a printing voltage of 24 V, a printing cycle of 8 ms, a pulse width of 0.7, 0.8, 1.0,
Printing was performed in seven stages of 1.2, 1.4, 1.6, and 2.0 milliseconds, and the coloring sensitivity (coloring density) was compared visually. The coloring sensitivity was evaluated on the following six levels. 0: The color sensitivity is extremely poor, and no color is formed. 1: The coloring sensitivity is considerably poor, and almost no coloring occurs. 2: Poor color development sensitivity and poor practicality. 3: Color development sensitivity is at the limit of practical use. 4: Good color development sensitivity and sufficiently enduring practical use. 5: Very good color sensitivity.

<Evaluation 2 Heat Resistance of Heat-Sensitive Recording Material> The heat-sensitive recording materials prepared in Examples 1 to 21 and Comparative Examples 1 to 8 were colored in Evaluation 1 with a color printing paper having a pulse width of 1.6 milliseconds. An electric oven with an inner volume of 200 liters at 50 ° C
After being left for 8 hours in each of the color printings, the density of each color printing was compared with each color printing without performing the electric oven treatment, and evaluated visually by the following six steps. 0: All records disappeared. 1: Corresponding record disappeared. 2: Record partially disappeared. 3: Loss of recording is small enough to be practical. 4: There is almost no loss of recording. 5: There is no loss of the record at all.

<Evaluation 3: Plasticizer resistance of record> The print record obtained in Evaluation 1 was inserted from above and below with two plastic wrap films made of polychlorinated polyvinyl chloride containing a plasticizer, and 20 g /
After placing a weight of ² cm ² and leaving it at 20 ° C. for 4 hours, it was visually evaluated in the following five steps as compared with the first printing. 0: All records disappeared. 1: Corresponding record disappeared. 2: Record partially disappeared. 3: Loss of recording is small enough to be practical. 4: There is almost no loss of recording.

Table 1 shows the results.

[0067]

[Table 1]

[0068]

As can be seen from Table 1, the heat-sensitive recording material according to the present invention has high color sensitivity, good storage stability, lowering of color sensitivity due to volatilization of the sensitizer, and generation of head residue. It has excellent properties such as absence.

Further, 4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, and 2,4'-dihydroxydiphenylsulfone, which have conventionally been found to be difficult to use because no suitable sensitizer having a high melting point has been found. It can be said that, for example, 4,4-di (phenylsulfonyl) -5-methylphenol has become significant in the use of the present invention in heat-sensitive recording materials.

Continued on the front page (72) Inventor Takaaki Mori 1-10-24, Itikaichi, Ibaraki-shi, Osaka Inside the Sanko Development Research Institute (72) Inventor Tomoyuki Tanemura 1-110-24, Itikaichi, Ibaraki-shi, Osaka Co., Ltd. F-term in Sanko Development Research Institute (reference) 2H026 AA07 BB02 BB24 BB25 BB30 DD02 DD09 DD12 DD17 DD43 DD45 DD46

Claims (4)

[Claims] 1. A heat-sensitive recording material utilizing a color-forming reaction between an electron-donating leuco dye and an acidic developer for forming the dye, the cyclic imide compound represented by the general formula (1) or (2) A heat-sensitive recording material comprising: Embedded image (In the formula, n represents 2 or 3, and R ¹ represents an alkyl group having a substituent or an aryl group optionally having a substituent.) (In the formula, n represents 2 or 3, and R ² represents an alkylene group which may have a substituent in the chain, or a divalent aromatic hydrocarbon ring group.) 2. The method according to claim 1, wherein the cyclic imide compound represented by the general formula (1) or (2) is N-benzylsuccinimide,
N- (4-methylbenzyl) succinimide, N-phenethylsuccinimide, N- {2- (2-naphthoxy)
Ethyl @ succinimide, N- (3-phenoxypropyl) succinimide, N- {3- (4-tolyloxy) propyl} succinimide, N-phenylsuccinimide, N- (3-tolyl) succinimide, N- (4-tolyl) succinimide , N- (2,4-xylyl) succinimide, N-phenylglutarimide, N- (4-
At least one selected from tolyl) glutarimide, N, N '-(1,4-butylene) bissuccinimide or N, N'-(1,6-hexylene) bissuccinimide
The heat-sensitive recording material according to claim 1, which is a seed. 3. Stearoylamide, 1,2-diphenoxyethane, 1,2-di (3-tolyloxy) ethane,
-Benzyloxynaphthalene, di (4-methylbenzyl)
3. The heat-sensitive recording material according to claim 1, further comprising at least one selected from oxalate and acetotoluidide. 4. The method according to claim 1, wherein the acidic developer is 4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone or 2,4-di (phenylsulfonyl). The heat-sensitive recording material according to any one of claims 1 to 3, which is))-5-methylphenol.