JPH05221147A - Thermal recording material - Google Patents

Abstract

PURPOSE:To enhance heat resistance and solvent resistance of image by adding a compound represented by a specified general formula to an electron acceptive compound being employed in thermal recording material for a desk top electronic calculator. CONSTITUTION:A compound represented by formula I is added as an electron acceptive compound composing a thermal recording material. In formula I, R represents a lower alkyl group, M represents a metallic atom, and (n) represents the valency of the metallic ayom. A compound represented by formula II, e.g. 3-(4'-diethylamino-2'-methoxyphenyl)-3-((4''-p-dimethylaminophenyl-4''- phenyl)-l'',3''-butadiene-1''-il) phthalide, is added as an electron donative colorless dye. In formula II, R represents a lower alkyl group, X represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a dialkylamino group or a halogen atom, A represents a benzene ring or a naphthalene ring, and (n) represents 0 or 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in computer output, calculator printer field, medical measurement recorder field, low speed and high speed facsimile field, automatic ticket vending machine field, thermal copying field, POS system label field and the like. The present invention relates to a heat-sensitive recording material that is widely used, and particularly to a heat-sensitive recording material that is excellent in oil resistance of an image and a heat-sensitive recording material that is excellent in oil resistance of an image in the near infrared region and heat resistance of the background.

[0002]

2. Description of the Related Art A heat-sensitive recording material utilizing a heat-coloring reaction between a generally colorless or light-colored electron-donating colorless dye and an electron-accepting compound such as phenols and organic acids is disclosed in JP-B-43-4.
160, Japanese Patent Publication No. 45-14039, Japanese Patent Laid-Open No. 48-2.
It has been widely put to practical use since it was announced in Japanese Patent No. 7736. In particular, this system has a great maintenance advantage compared to other recording materials, so a facsimile printer,
It is used in bar code labels.

Examples of phenolic substances used in these heat-sensitive recording materials are 2-2'-bis (4-hydroxyphenylpropane, 1,7- (bis-P-hydroxyphenylthio) -3,5-.
Many proposals such as dioxaheptane, 1,1-bis (4-hydroxyphenyl) cyclohexane, and 4-hydroxy-4′isopropyloxydiphenylsulfone have been proposed. However, thermal recording materials using these phenyl-based color developing materials are
It has the drawback that the background color develops when it comes into contact with oil or a plasticizer.

On the other hand, as a method for improving the stability of the formed image, JP-A-62-82070 and JP-A-62-18 are used.
7079, JP-A-63-17085, JP-A-1-1.
No. 90486, JP-A-2-122977, and the like, the idea of using a metal salt of a salicylate compound as a developer is proposed, but these methods can improve the stability of the image portion, but the background portion Is not stable enough,
At present, it cannot be said that there is sufficient stability in terms of legibility.

On the other hand, in order to improve the above points in the conventional heat-sensitive recording material, there is proposed a water-soluble polymer overcoat layer provided on the heat-sensitive color developing layer. This has the drawback that the overcoat layer impedes heat conduction, resulting in poor heat sensitivity and high cost.

Further, with the spread of semiconductor lasers,
There is a movement to read records such as codes with a semiconductor laser. Above all, the near-infrared region of 650 to 900 nm is the wavelength region of the present semiconductor laser, and there is a great demand for a thermal recording paper having absorption in this region. As proposals of recording materials corresponding to these, Japanese Patent Laid-Open Nos. 51-121035 and 58
Examples are found in JP-A-157779, JP-A-60-27589 and JP-A-63-165379. However, in recent years, with the increasing demand for near-infrared absorption type heat-sensitive materials,
Similar to the conventional thermosensitive recording label, the image is oil or plasticizer,
Further, high reliability against heat is desired, and on the other hand, the recording material disclosed in the above publication cannot provide sufficient reliability, and further improvement is required.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat-sensitive recording material which overcomes the drawbacks of the prior art and is excellent in oil resistance of images. further,
It is an object of the present invention to provide a recording material excellent in heat resistance and solvent resistance of an image, which is particularly demanded in the near infrared absorption type heat sensitive material.

[0008]

According to the present invention, a heat-sensitive recording material comprising an electron-donating colorless dye and an electron-accepting compound contains at least a compound represented by the following general formula (I) as the electron-accepting compound. A heat-sensitive recording material is provided.

[0009]

[Chemical 1]

Further, in the present invention, as the electron-donating colorless dye, the following general formula (II), structural formulas (III) and (I
By using the compound represented by V) in combination with the electron-accepting compound represented by the general formula (I), a heat-sensitive recording material having excellent heat resistance and solvent resistance in the near infrared region is provided. ..

[Chemical 2]

[Chemical 3]

The heat-sensitive recording material of the present invention is excellent in oil resistance by utilizing the compound represented by the general formula (I) as an electron-accepting compound. Specific examples of the compound represented by formula (I) used in the present invention are shown below, but the invention is not necessarily limited thereto.

[0012]

[Table 1] Table 1

[Table 2] Table 2

Specific examples of the electron donating dye represented by the general formula (II) include the following. 3- (4'-diethylamino-2'-methoxyphenyl) -3-
{(4 "-p-dimethylaminophenyl-4" -phenyl) -1 ",
3 "-butadiene-1" -yl} phthalide, 3- (4'-diethylamino-2'-methoxyphenyl) -3-{(4 "-p-dimethylaminophenyl-4" -chlorophenyl) -1 ", 3 "-butadiene-
1 "-yl} phthalide, 3- (4'-diethylamino-2'-methoxyphenyl) -3-{(4" -p-dimethylaminophenyl-4 "-
p-toluyl) -1 ", 3" -butadiene-1 "-yl} phthalide,
3- (4'-diethylamino-2'-methoxyphenyl) -3-
{(4 "-p-dimethylaminophenyl-4" -methoxyphenyl) -1 ", 3" -butadiene-1 "-yl} phthalide, 3- (4'-
Diethylamino-2'-methoxyphenyl) -3-{(4 "-p-dimethylaminophenyl-4" -phenyl) -1 ", 3" -butadiene-1 "-yl} benzophthalide, 3- (4'-diethylamino -
2'-methoxyphenyl) -3-{(4 "-p-dimethylphenyl-
4 "-p-chlorophenyl) -1", 3 "-butadiene-1" -yl}
Benzophthalide, 3- (4'-diethylamino-2'-methoxyphenyl) -3-{(4 "-p-dimethylaminophenyl-4" -toluyl) -1 ", 3" -butadiene-1 "-yl} benzophthalide , 3- (4'-diethylamino-2'-methoxyphenyl) -3-
{(4 "-p-dimethylaminophenyl-4" -p-methoxyphenyl) -1 ", 3" -butadiene-1 "-yl} benzophthalide,
3- (4'-diethylamino-2'-methoxyphenyl) -3-
{(2 "-p-Dimethylaminophenyl-2" -phenyl) -ethylene-1 "-yl} phthalide, 3- (4'-diethylamino-2'-
Methoxyphenyl) -3-{(2 "-p-dimethylaminophenyl-2" -p-chlorophenyl) -ethylene-1 "-yl} phthalide, 3- (4'-diethylamino-2'-methoxyphenyl) -3 -
{(2 "-p-Dimethylaminophenyl-2" -p-toluyl) -ethylene-1 "-yl} phthalide, 3- (4'-diethylamino-2 '
-Methoxyphenyl) -3-{(2 "-p-dimethylaminophenyl-2" -p-methoxyphenyl) -ethylene-1 "-yl} phthalide, 3- (4'-diethylamino-2'-methoxyphenyl) -3-{(2 "-p-dimethylaminophenyl-2" -phenyl) -ethylene-1 "-yl} benzophthalide, 3- (4'-diethylamino-2'-methoxyphenyl) -3-{(2" -p-dimethylaminophenyl-2 "-chlorophenyl) -ethylene-1"-
Il} benzophthalide, 3- (4'-diethylamino-2'-p-
Methoxyphenyl) -3-{(2 "-p-dimethylaminophenyl-2" -methoxyphenyl) -ethylene-1 "-yl} benzophthalide, 3- (4'-diethylamino-2'-methoxyphenyl) -3- {(2 "-p-dimethylaminophenyl-2" -p-toluyl) -ethylene-1 "-yl} benzophthalide and the like.

The electron-donating colorless dye used in the present invention may be used alone or as a mixture of two or more kinds, and as such a dye, those applicable to the recording material of this kind are arbitrarily applied. Triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, and indolylphthalide-based leuco compounds are preferable, and specific examples thereof include the following. 3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3
-Bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3-dibutylamino-7- (2'-fluoroanilino) -fluorane, 3-pyrrolidyl-7-dibenzylaminofluorane, 3,6 -Bis (diphenylamino) -fluorane, 3-diethylamino-7- (2'-chloroanilino) -fluorane, 3-N-ethyl-3-N-isoamylamino-6-methyl-7
-Anilinofluorane, 3-diethylamino-6-methyl-7-
Anilinofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-dibutylamino-7- (2'-chloroanilino) fluorane, 3-diethylamino-7-chloro-fluorane, 3-diethylamino-6 -Methyl-7-chlorofluorane, 3-N-methyl-N-cyclohexyl-6-chlorofluorane, 3-diethylamino-6-methyl-7- (2 ', 4'-dimethylanilino) fluorane, 3- Diethylamino-7-dibenzylaminofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-N-ethyl-N-furfurylamino-6-methyl-7- Anilino Fluoran, 3-N-
Ethyl-N-isobutyl-6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3-N-dibutyl-7- (2'-chloroanilino) fluorane, 3 -Diethylamino-6-ethoxyethyl-7-anilinofluorane, 3-diethylamino-7-anilinofluorane, 3
-Dibutylamino-6-methoxy-7-anilinofluorane,
3,6-bis (diethylamino) thiofluorane, 3,3-bis (1'-ethyl-2'-methylindol-3-yl) phthalide and the like.

These electron-donating colorless dyes can also be used together in the heat-sensitive recording material using the dyes of structural formulas (III) and (IV) for the purpose of color tone correction.

In the present invention, the compound represented by the general formula (I) is used as the electron-accepting compound, but other electron-accepting compound can be used in combination if necessary. Specific examples thereof include the following. 4,4'-isopropylidene bisphenol, 4,4'-diphenol sulfone, 4-isopropoxy-4 '
-Hydroxydiphenyl sulfone, 4-benzyloxy-4 '
-Hydroxydiphenyl sulfone, bis- (4-hydroxy
-3-allylphenyl) sulfone, p-hydroxybenzoic acid benzyl, bis- (4-hydroxyphenyl) acetic acid methyl ester, bis- (4-hydroxyphenyl) acetic acid benzyl ester, bis- (4-hydroxy-3-methylphenyl )
Sulfide, 1,7-bis (p-hydroxyphenylthio)-
3,5-dioxaheptane, 3,4-dihydroxy-4'-methyl sulfone, 2,4'-diphenol sulfone, 1,3-bis (4-hydroxycumyl) benzel, benzyl protocaticate, 1 , 3-bis (4-hydroxyphenylthio) propane,
1,3-bis (4'-hydroxyphenylthio) -2-hydroxypropane and the like.

Further, in the case of obtaining the heat-sensitive recording material according to the present invention, various heat-fusible substances can be used as a heat-sensitivity improving agent, if necessary, and specific examples thereof include the following compounds. Stearic acid, behenic acid, stearic acid amide, p-benzylbiphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, 1-hydroxy
-2-phenyl naphthoate, diphenyl carbonate, dibenzyl terephthalate, dibenzyl oxalate,
Oxalic acid bis (p-tolylmethyl) ester, 1,4-bis (2-vinyloxyethoxy) benzene, 1,4-bis (phenylthio) butane, 1,2-bis (3'-methylphenoxy)
Ethane, 1,4-bis (phenoxy) ethane, etc.

In the case of obtaining a heat-sensitive recording material according to the present invention, auxiliary additive components such as filler, if necessary,
A surfactant or the like can be used in combination. In this case, as the filler, inorganic fine powder such as calcium carbonate, aluminum hydroxide, barium sulfate, silica, clay, talc, kaolin, etc., or organic system such as urea-formalin resin, styrene / methacrylic acid copolymer, polystyrene resin, etc. Fine powder can be used.

Further, in order to produce the heat-sensitive recording material of the present invention, a leuco dye, a color developer, and an auxiliary component may be bound and supported on a support. In this case, various conventional binders may be used. Can be used as appropriate, and specific examples thereof include the following. Polyvinyl alcohol, starch, methoxy cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose,
Sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylic acid ester copolymer, acrylamide / acrylic acid ester / methacrylic acid terpolymer,
Styrene / maleic anhydride copolymer, isobutylene / maleic anhydride copolymer alkali salt, polyvinyl acetate, polyurethane, polyacrylic acid ester, polymethacrylic acid ester, vinyl chloride / vinyl acetate copolymer and the like.

[0020]

EXAMPLES Examples of the present invention will be shown below. Parts and% are based on weight. [Examples 1 to 6] [Comparative Examples 1 to 3] Mixtures having the following compositions were separately dispersed using a magnetic ball mill to prepare [A liquid] to [D liquid]. As shown in Table 2, the B group compound of [solution B] was replaced and the heat-sensitive recording materials of Examples 1 to 6 and Comparative Examples 1 to 3 were prepared. [Solution A] 3-dibutylamino-6-methyl-7-anilinofluorane 10 parts 10% aqueous solution of polyvinyl alcohol 10 parts water 30 parts [Solution B] Compound shown in Group B of Table 2 10 parts 10% polyvinyl alcohol Aqueous solution 10 parts Water 30 parts [C liquid] Calcium carbonate 10 parts 10% polyvinyl alcohol aqueous solution 10 parts Water 30 parts [D liquid] Zinc stearate 10 parts 10% polyvinyl alcohol aqueous solution 10 parts Water 30 parts Next [liquid A]- [D liquid] to [A liquid]: [B liquid]: [C
Liquid]: [D liquid] = 1: 3: 4: 1 by mixing to prepare a heat-sensitive coating liquid, and a dry weight of 4 to 5 g / m ² of high-quality paper.
After coated to a 5 g / m ^2, Beck Namerado 500-3,
Calendar processing is performed so that the time becomes 000 seconds.
6] and the heat-sensitive recording materials of [Comparative Examples 1 to 3].

The following test was conducted on the thermal recording material prepared as described above. The results are shown in Table 3. Coloring property: The density of the color-developed part and the background part when the color was developed at 150 ° C using a thermal gradient tester was measured with a Macbeth densitometer. Oil resistance: Apply cottonseed oil to the color-developed material that has been colored at 150 ° C using a thermal gradient tester and the background, and leave it for 16 hours under the test conditions of 40 ° C. Then use the Macbeth densitometer to measure the density of the colored and background areas. It was measured. From the results in Table 3, it can be seen that the heat-sensitive recording material of the present invention has excellent oil resistance.

[0022]

[Table 3] Table 3

[Examples 7 to 11] In Example 1, [A
Liquid], Examples 7 to 11 were prepared in the same manner except that the compounds shown in Group A of Table 4 were used in place of 3-dibutylamino-6-methyl-7-anilinofluorane. Examples 7 to 11 are classified according to the compounds of group A in Table 4.

[Comparative Examples 4, 5 and 6] The compounds shown in Group B of Table 4 were used in place of the zinc 2-methoxy-3-naphthoate in [Liquid B] in Examples 7, 9 and 11. Comparative Examples 4, 5 and 6 were prepared in the same manner except for the above.

The thermal recording paper prepared as described above was subjected to the following tests, and the results are shown in Table 4. Color developability: The reflectance at 780 mm and 900 mm of the color development part and the background part when color was developed at 150 ° C. using a thermal gradient tester was measured with Hitachi spectrophotometer 330 type and PCS (P
rint Contrast Signal) value was calculated. Solvent resistance: Colored product colored at 150 ° C using a heat gradient tester, toluene is applied to the background, and the reflectance of 780 mm and 900 mm of the colored part and the background after 16 hours is measured to obtain a PCS value. I asked.

[0026]

[Table 4] Table 4

[Examples 12 to 16] In Example 1, [A
Liquid], Examples 12 to 15 were prepared in the same manner except that the compounds shown in Group C of Table 4 were used instead of 3-dibutylamino-6-methyl-7-anilino) -fluorane. [Comparative Examples 6, 7 and 8] In Examples 12, 14 and 16, [B
Liquid], Comparative Examples 6 and 7 were prepared in the same manner except that the compounds shown in Group D of Table 4 were used instead of zinc 2-methoxy-3-naphthoate.

The thermosensitive recording paper prepared as described above was subjected to the same color development test as in Example 7 and the heat resistance test described below, and the results are shown in Table 5. Heat resistance: What was colored at 150 ° C using a thermal gradient tester was left for 16 hours at 80 ° C and Dry conditions, and then the reflectance of 780 mm and 900 mm of the colored part and the background part was measured to obtain the PCS value. .. The results are shown in Table 5.

[0029]

[Table 5] Table 5

It is clear from Tables 4 and 5 that the heat-sensitive recording material of the present invention is a near-infrared absorbing heat-sensitive recording material having excellent oil resistance and heat resistance for near-infrared absorption.

[0031]

The image formed by the heat-sensitive recording material of the present invention is excellent in oil resistance by using the compound represented by the general formula (I) as an electron-accepting compound, and at the same time, is characterized by the general formula (II) and others. By combining with an electron-donating colorless dye represented by the structural formulas (III) and (IV),
When reading in the near-infrared region, it has excellent heat resistance and solvent resistance.

Claims (3)

[Claims] 1. A heat-sensitive recording material comprising an electron-donating colorless dye and an electron-accepting compound, wherein the electron-accepting compound contains at least a compound represented by the following general formula (I). material. 2. The heat-sensitive recording material according to claim 1, wherein the electron-donating colorless dye contains at least a compound represented by the following general formula (II). 3. The heat-sensitive recording material according to claim 1, wherein the electron-donating colorless dye contains at least a compound represented by the following structural formula (III) or (IV).