JPH01174589A - Heat-sensitive recording material - Google Patents

Abstract

PURPOSE:To obtain the subject material having high sensitivity, high whiteness, excellent light resistance, causing neither whitening nor fading, having a coloring layer comprising leuco dye using an ether compound of bisphenol sulfonic acid and adipic acid dichlorobenzene as a developer. CONSTITUTION:The aimed material having a heat-sensitive coloring layer obtained by using (A) 1pt.wt. leuco dye, (B) preferably 1-10pts.wt. (especially 2-6pts.wt.) monoether compound of 4,4'-bisphenolsulfonic acid shown by the formula (R is alkyl, aryl or aralkyl) and (C) preferably 0.5-5pts.wt. (especially 0.5-2pts.wt.) one or more compounds selected from the group consisting of adipic acid di-O-chlorobenzene, diphenacyl thiopropionate and oxalic acid diparachlorobenzene.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a heat-sensitive recording material, and more specifically to a dye precursor that is normally colorless or light-colored and a so-called developer that develops color by reacting with the dye precursor. This invention relates to a heat-sensitive recording material that utilizes a color reaction with a coloring agent.

[Prior Art] A so-called two-component heat-sensitive recording material that utilizes a color reaction between a colorless or light-colored electron-donating dye precursor and an electron-accepting compound is a two-component heat-sensitive recording material that uses a colorless or light-colored electron-donating dye precursor and an electron-accepting compound. Dispersed into fine particles, mixed with adhesives, pigments, wax, etc., applied to a support such as paper or film, dried, and heated to melt or vaporize one or both of them. Records are obtained using a color reaction.

These two-component color-forming heat-sensitive recording materials are: ■ - secondary color development and does not require development; ■ Printing is possible using a relatively simple and compact device; ■ Easy handling; It has great utility value because of its advantages such as high color density and (2) ease of producing heat-sensitive recording materials with various color tones.

For this reason, it is most widely used as a heat-sensitive recording material. Particularly in recent years, its use has been remarkable in the fields of facsimiles, computer output, medical measurement recorders, CAD printer paper, and PO8O8 scale labels.

The above-mentioned heat-sensitive recording materials are manufactured by coating and drying a heat-sensitive coloring liquid containing a coloring component that can cause a coloring reaction when heated, on a support such as ordinary paper, synthetic paper, or synthetic resin film. A colored image is recorded on the heat-sensitive recording material obtained by heating it with a thermal pen or a thermal head.

As such a heat-sensitive recording material, Japanese Patent Publication No. 43-4160
Heat-sensitive recording materials disclosed in Japanese Patent Publication No. 45-14039 and the like are known, but such conventional heat-sensitive recording materials have low thermal responsiveness and do not have sufficient color density during high-speed recording. There were problems such as not being able to obtain it, and it could not be said to be desirable.

As a method to improve these problems, JP-A No. 49-3
No. 4842 discloses acetamide, stearamide, m
-Nitrogen-containing compounds such as nitroaniline and dinitrile phthalate, acetoacetic acid anilide in JP-A-52-106746, and N,N in JP-A-53-11036.
- diphenylamine derivatives, benzamide derivatives, carbazole derivatives, etc.; JP-A-53-89139 contains alkylated biphenyls and biphenylalkanes; JP-A-58-144193 contains p-oxybenzoic acid ester derivatives. A method is disclosed for increasing speed and sensitivity by increasing
A method using hydroxyphthalic acid dimethyl ester as a color developer is also known as an effective method.

[Problems to be Solved by the Invention] However, even when these various color developers are used, so-called whitening phenomena occur, such as browning of recorded images and formation of white powder on the surface of image areas. It still has the disadvantage of

The purpose of the present invention is to provide a highly sensitive heat-sensitive recording material that has improved the above conventional drawbacks, that is, has high sensitivity, high whiteness, good light resistance, and is free from whitening, fingerprints, etc. It is an object of the present invention to provide a heat-sensitive recording material whose color does not fade due to oils and fats.

[Means for Solving the Problems] As a result of intensive research, the present inventors have found that, in a heat-sensitive recording material having a heat-sensitive color forming layer that utilizes a color-forming reaction between a leuco dye and a color developer, the color developer 4.4'-Bisphenolsulfone monoether compound, and at least one compound selected from the group consisting of di-0-chlorobenzene adipic acid, diphenacyl thiodipropionate, and diphenacyl oxalate. It has been found that the above-mentioned drawbacks can be improved by a heat-sensitive recording material characterized by containing the following.

Examples of the monoether compound of 4,4'-bisphenolsulfone used as a color developer in the present invention include the following.

4-hydroxy-4'-methoxydiphenylsulfone 4-hydroxy-4'-ethoxydiphenylsulfone 4-hydroxy-4'-isopropoxydiphenylsulfone 4-hydroxy-4'-n-propoxydiphenylsulfone 4-hydroxy-4'- n-Butoxydiphenylsulfone 4-hydroxy-4'-isobutoxydiphenylsulfone 4-hydroxy-4' -see -butoxydiphenylsulfone 4-hydroxy-4' -tar -butoxydiphenylsulfone 4-hydroxy-4'-benzyloxydiphenyl Sulfone 4-Hydroxy-4'-phenoxydiphenylsulfone 4-hydroxy-4'-(p-methylbensiloxy)diphenylsulfone These monoether compounds of 4.4'-bisphenolsulfone have a high whiteness when used alone. Although not low, the color density is low, and the thermal response or density uniformity of the color image is slightly inferior, but when combined with di-0-chlorobenzene adipic acid, diphenacyl thiodipropionate, civachlorbenzene oxalate, etc. When used, almost no whitening phenomenon occurs. Moreover, a highly sensitive thermal recording paper with high whiteness can be obtained.

In the present invention, the color developer 4,4'- and the monoether compound of sphenolsulfone are used in an amount of 1 part by weight per 1 part by weight of the leuco dye.
It is preferable to use it in a range of 10 parts by weight. Particularly preferred is a range of 2 to 6 parts by weight.

Di-0-chlorobenzene adipate, diphenacyl thiodipropionate, or di-parachlorobenzene oxalate are used as sensitizers. Generally, it is suitable to use the leuco dye in a proportion of 0.5 to 5 parts by weight, preferably 0.5 to 2 parts by weight, per part by weight of the leuco dye. In addition, if the sensitizer blending ratio is 0
．． When the amount is less than 5 parts by weight, sufficient sensitivity cannot be obtained.

On the other hand, when the amount exceeds 5 parts by weight, the sensitivity is good, but
The static color density at 70° C. increases, which is undesirable because it tends to cause a fogging phenomenon in which non-image areas develop color during continuous printing. These sensitizers may be used alone or in combination.

In the present invention, any leuco dye conventionally used in this type of heat-sensitive recording material can be used. For example, leuco compounds of triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, and indrifthalide-based dyes can be used alone or in combination.
Use by mixing more than one species.

Specific examples of such leuco dyes are as follows.

3.3-bis(p-dimethylaminophenyl)-phthalide, 3.3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone), 3.3-bis(p- dimethylaminophenyl)-6-dimethylaminophenyl, 3.3-bis(p-dimethylaminophenyl)=6-chlorphthalide, 3.3-bis(p-dimethylaminophenyl)-phthalide, 3-cyclohexylamino-6 -chlorofluorane, 3-dimethylamino-5,7-dimethylfluorane, 3
-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-6
-Methyl-7-chlorofluorane, 3-(N-p-tolyl-N-ethylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2- (N-(3'-)lifluoromethylphenyl)
amino)-6-dinithylaminofluorane, 2-(3
, 6-bis(diethylamino)-9-(0-chloroanilino)xantylbenzoic acid lactam), 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran, 3-diethylamino-
7-(o-chloroanilino)fluoran, 3-dibutylamino-7-(o-chloroanilino)fluoran, 3-N-methyl-N-amylamino-6-methyl-7-
Anilinofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6
-Methyl-7-anilinofluorane, 3-(N,N-diethylamino)-5-methyl-7-
(N,N-dibenzylamino)fluorane, benzoylleucomethy, Renblue, 6'-chloro-8'-methoxybenzoindolino-pyrylospirane, 6'-bromo-3'-methoxy-benzoindolino-pyrylospirane, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-chlorophenyl)
Phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-nitrophenyl)
Phthalide, 3-(2'-hydroxy-4'-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl)
Phthalide, 3-(2'-methoxy-4'-dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'-methylphenyl)phthalide, 3-morpholino-7-(N-propyl- trifluoromethylanilino)fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7-(N-benzyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7 -(di-p-chlorophenyl)methylaminofluorane, 3-diethylamino-5-chloro-7-(α-phenylethylamino)fluoran, 3-(N-ethyl-p-toluidino)-7-(α- 3-diethylamino-7-(O-methoxycarbonylphenylamino)fluoran, 3-diethylamino-5-methyl-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-biperidino Fluorane, 2-chloro-3-(N-methyltoluidino)-7-(p
-n-butylanilino)fluoran, 3-(N-benzyl-N-cyclohexylamino)-5,6-benzo-
7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino 4
', 5'-benzofluorane, etc.

Various binders can be used as appropriate to bind and support these leuco dyes and color developers on the support.

Specific examples are as follows. Polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylic amide/acrylic ester copolymer, acrylic amide/acrylic acid Ester/methacrylic acid ternary copolymer, styrene/maleic anhydride copolymer alkali salt, isobutylene/maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate,
In addition to water-soluble polymers such as gelatin and casein, polyvinyl acetate, polyurethane, styrene/butadiene copolymers,
Polyacrylic acid, polyacrylic ester, vinyl chloride/vinyl acetate copolymer, polybutyl methacrylate, ethylene/vinyl acetate copolymer, styrene/butadiene,
Acrylic acid ester copolymer latex, etc.

Furthermore, in the heat-sensitive recording material of the present invention, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as pigments, surfactants, thermofusible substances, etc., may be used in combination, if necessary.

Pigments include calcium carbonate, silica, zinc oxide, tan oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, surface-treated powders such as calcium and silica, urea-formalin resin, styrene/methacrylic acid. Examples of heat-fusible substances include organic fine powders such as copolymers and polystyrene resins. Examples of thermofusible substances include higher fatty acids or their ester amides or metal salts, various waxes, and combinations of aromatic carboxylic acids and amines. Examples include condensates, benzoic acid phenyl esters, higher linear glycol 3.4 epoxy-dialkyl hexahydrophthalates, higher ketones, and others having a melting point of about 50°C to 200°C.

The heat-sensitive recording material of the present invention is manufactured by coating a heat-sensitive layer-forming coating liquid containing the above-mentioned components onto a suitable support such as paper, synthetic paper, or plastic film and drying it, and is applied to various recording fields. be done.

[Examples] Next, the present invention will be explained in more detail with reference to Examples. Note that all parts and percentages shown below are based on weight.

Example 1 [Liquid A] 3-N-methyl-3-N-cyclohexylamino-6-methyl-7-anilinofluorane 300 parts lO% polyvinyl alcohol aqueous solution 300 parts water
400 parts [Liquid B] 4-hydroxy-4'isopropoxydiphenyl sulfone 300 parts 10% polyvinyl alcohol aqueous solution 200 parts water
400 parts [Liquid C] Di-0-chlorobenzene adipic acid 100 parts Calcium carbonate 300 parts 10% polyvinyl alcohol 200 parts Water
Six solutions of 300 parts A, B, and C were prepared by dispersing each of the above compositions using a sand grinder until the particle size became 0.8 μm or less.

Next, 20 parts of liquid A, 70 parts of liquid B, and 10 parts of liquid C were mixed to prepare a thermosensitive coloring layer forming liquid, and this was spread on synthetic paper with a thickness of 80μ so that the weight after drying was 5 g/rrr. A heat-sensitive recording material was prepared by applying and drying with a Mayer bar and calendering the surface to a smoothness of 4000 sce.

Example 2 A heat-sensitive recording sheet was prepared in the same manner as in Example 1, except that the same amount of diphenacyl thiodipropionate was used in place of di-O-chlorobenzene adipic acid in Solution C of Example 1.

Example 3 A heat-sensitive recording sheet was prepared in the same manner as in Example 1 except that di-0-chlorobenzene adipic acid in Solution C of Example 1 was replaced with the same amount of di-parachlorobenzene oxalate.

Example 4 The same amount of 4-hydroxy-4 was used in place of 4-hydroxy-4'-isopropoxydiphenylsulfone in Solution B of Example 1.
A thermosensitive recording sheet was prepared in the same manner as in Example 1 except that '-n-butoxydiphenyl sulfone was used.

Example 5 The same amount of 4-hydroxy-4 was used in place of 4-hydroxy-4'-isopropoxydiphenylsulfone in Solution B of Example 2.
'A thermosensitive recording sheet was prepared in the same manner as in Example 2 except that benzyloxydiphenyl sulfone was used.

Comparative Example l A thermosensitive recording sheet was prepared by repeating Example 1, except that the same amount of benzyl p-hydroxybenzoate was used in place of 4-hydroxy-4' isopropoxydiphenyl sulfone in Solution B in Example 1. .

Comparative Example 2 A thermosensitive recording sheet was prepared by repeating Example 1 except that the same amount of dibenzyl terephthalate was used in place of di-0-chlorobenzene adipic acid in Solution C in Example 1.

Each row of thermal recording materials was tested for excitation color sensitivity, thermal paper whiteness, and image whitening.

The results are shown in Table-1.

The test method is as follows.

(1) Dynamic color development sensitivity In a heat-sensitive printing experiment device manufactured by Matsushita Electronics Components and equipped with a thin film head, the head heat amount was 0.721 and 0.849.

0.595, 0.541, 0.4B9, 0.41
5, 0.3B0.

0.288, 0.234, 0.180 millijoules/dot.

1 line recording time 7, 'Ims/β, scanning line density 8
×3.85 dots/mm
6).

(2) Image whitening After the print density of 1.0 to 1.2 was left at room temperature for 15 days, it was judged visually.

○...No whitening.

Δ... Some whitening is observed, but it can be used. 'X: Cannot be used due to excessive whitening.

(3) Whiteness measurement - Measured with a Hunter whiteness meter (using pull filter Toyo Seiki ■) [Effects of the invention] The present invention has extremely high sensitivity compared to conventional ones.
Moreover, it was possible to provide a heat-sensitive recording material of good quality with extremely little fading or whitening of recorded images and a high degree of whiteness.

Claims (1)

[Scope of Claims] In a heat-sensitive recording material having a heat-sensitive coloring layer that utilizes a color-forming reaction between a leuco dye and a color developer, the heat-sensitive coloring layer has a general formula ▲a mathematical formula, a chemical formula, a table, etc. as a color developer▼ (R represents an alkyl group, an aryl group, or an aralkyl group), and further contains di-o-chlorobenzene adipic acid, diphenacyl thiodipropionate, and A heat-sensitive recording material characterized by containing at least one compound selected from the group consisting of acid di-parachlorobenzene.