JPH09188072A - Thermosenstive color developing composition and thermal recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain thermosensitive color developing recording material (sheet) having excellent color developability and preservability. SOLUTION: The thermosensitive color developing composition contains developable compound, color developing compound for color developing in reaction with the developable compound by heating and polymer compound dispersed inorganic solvent, and comprises 2-(o-fluoroanilino)-6- diethylaminofluoran or 2-(o-chloroanilino)-6-diethylaminofluoran as color developable compound and 2,4'-dihydroxydiphenylsulfone as developable compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive coloring composition and a thermosensitive recording material. More specifically, the present invention relates to an organic solvent-dispersed thermosensitive coloring composition having excellent coloring properties and storage stability, and a thermosensitive recording material obtained by applying and drying the composition.

[0002]

2. Description of the Related Art Generally, a thermosensitive recording material is prepared by separately dispersing a developer such as a leuco dye and a phenolic substance into fine particles, and then mixing the two with a binder, a sensitizer, a filler, and the like. Additives such as lubricants to make a coating liquid, applied to paper, film, synthetic paper, etc., and the color is formed by the chemical reaction that occurs when one or both of the leuco dye and the developer are melted and contacted by heating Get the record. A thermal printer or the like having a built-in thermal head is used for color development of such a thermal recording sheet. This thermal recording method has the following advantages: (1) no noise during recording;
(2) No need for development, fixing, etc., (3) Maintenance-free, (4) Machines are relatively inexpensive, etc., so that they are in the facsimile field, computer output, printer fields such as calculators, medical care It is widely used in the field of recorders for measurement, the field of automatic ticket vending machines, the field of thermal recording labels, and the like.

[0003] Recently, the use of such features as application to vouchers such as commuter tickets and coupons, cards and the like has been expanding. The demand for the heat-sensitive recording material has also changed from one-time use (recording) to one that can withstand many uses, and the support of the heat-sensitive recording material is also made of paper with good mechanical strength and water resistance. There is a demand for conversion to a synthetic plastic film or synthetic paper.

Conventionally, a thermosensitive coloring composition (ink or paint, etc.) used for forming a thermosensitive coloring recording layer on a paper support is prepared by dispersing a thermosensitive recording material in which water is dispersed in a medium. This product had good adhesiveness to paper, but had poor coating and printability and adhesiveness to plastic films and synthetic papers, and was insufficient. Therefore, the use of a thermosensitive coloring composition using an organic solvent as a medium is considered, and although the coating property or printing property and adhesiveness are improved, the organic solvent used, a polymer compound as a binder, There are restrictions on the combination of heat-sensitive recording materials and the like, and there are dissatisfactions with the heat-sensitive recording characteristics, especially background fog and color sensitivity, as well as plasticizer resistance and oil resistance.

[0005]

The object of the present invention is as described above.
It is to solve the disadvantages of the prior art. That is, an object of the present invention is to provide an organic solvent type thermosensitive coloring composition and a recording material for forming a thermosensitive coloring recording layer having less background fogging, excellent coloring density and good storage stability.

[0006]

Means for Solving the Problems The present inventors have made various studies to achieve the above object, and as a result, completed the present invention. That is, the present invention relates to (1) a thermosensitive color-forming composition obtained by dispersing a color-developing compound, a color-forming compound which reacts with the color-developing compound under heating, and a polymer compound in an organic solvent. In this case, 2- (o-
Fluoroanilino) -6-diethylaminofluorane or 2- (o-chloroanilino) -6-diethylaminofluorane as a color-developing compound containing 2,4′-dihydroxydiphenyl sulfone. Composition, (2) Thermosensitive coloring composition of (1) wherein the organic solvent is a hydrocarbon-based organic solvent, (3) Thermosensitive coloring property of (2) the hydrocarbon-based organic solvent is liquid at room temperature Composition, (4) Thermosensitive color-forming composition according to (3), wherein the hydrocarbon-based organic solvent that is liquid at room temperature is aromatic hydrocarbon, naphthene-based hydrocarbon, or paraffin-based hydrocarbon, (5) (1) A heat-sensitive recording material obtained by applying the heat-sensitive color forming composition according to any one of (1) to (4) on a support and drying the composition.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The thermosensitive color-forming composition of the present invention comprises an organic solvent containing the above-mentioned color-forming compound, namely 2- (o-fluoroanilino) -6-diethylaminofluorane or 2- (o- It is obtained by mixing and dispersing with chloroanilino) -6-diethylaminofluorane, a color-developing compound, that is, 2,4′-dihydroxydiphenyl sulfone, a polymer compound, and other optional additives. The ratio in the thermosensitive color-developing composition is 2- (o-fluoroanilino) -6-diethylaminofluorane or 2- (o-fluoroanilino) -6-diethylaminofluorane.
With respect to 1 part by weight of (o-chloroanilino) -6-diethylaminofluorane, 1 to 10 parts by weight, and preferably 1 to 5 parts by weight of 2,4′-dihydroxydiphenyl sulfone are suitable. These color-forming compounds and color-developing compounds are contained in the composition as a total amount of both, and are 3% in the total solid content.
It is contained in an amount of 0 to 90% by weight, preferably 60 to 80% by weight.

Examples of the organic solvent include hydrocarbon solvents, preferably those which are liquid at room temperature. Specific examples include aromatic hydrocarbons, naphthene hydrocarbons and paraffin hydrocarbons. These solvents may be used alone or as a mixture. Examples of the aromatic hydrocarbon which is liquid at normal temperature include benzene, toluene, xylene, ethylbenzene, ethyltoluene and the like, and a mixture thereof. Among them, it is preferable to use toluene and / or xylene. Examples of naphthenic hydrocarbons that are liquid at room temperature include cyclopentane, methylcyclopentane, 1,1-dimethylcyclopentane, 1,3-dimethylcyclopentane, cyclohexane, ethylcyclohexane, 1,2,4-trimethylcyclohexane and the like. Or a mixture thereof. Among them, it is preferable to use cyclohexane and / or ethylcyclohexane. Examples of paraffinic hydrocarbons that are liquid at room temperature include n-hexane, n-heptane, n-octane, n-nonane, or isomers thereof.
Or a mixture thereof. This amount is about 50 to 1000 v / w%, preferably about 100 to 500 v / w%, based on the total amount of solids.

The polymer compound is used as a binder, and a polymer compound which is soluble in the organic solvent used and has a film-forming property is used. Specific examples thereof include polyvinyl chloride, acrylic resin, acrylic styrene copolymer, polyester resin, polycarbonate resin, polyurethane resin, polybutyral resin, epoxy resin, furan resin, vinyl toluene copolymer, rosin ester resin and the like. Can be These polymer compounds are present in the total solids of the composition in an amount of from 1 to 7
0% by weight, preferably 10 to 40% by weight.

In the composition of the present invention, other color-forming compounds, color-developing compounds and additives may be used or used in combination with the above-mentioned components, if necessary. Specific examples thereof are as follows. The amount used is about 0 to 30% by weight based on the total solid content in the composition.

Examples of the color-forming compound that can be used in combination include fluorane compounds, triarylmethane compounds, spiropyran compounds, diphenylmethane compounds, thiazine compounds, lactam compounds and fluorene compounds. Examples of the fluoran-based compound include 2-aniline-3-methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6- (N-methyl-N-cyclohexylamino) fluoran, and 2-anilino-3-methyl -6- (N-ethyl-N-isopentylamino) fluoran, 2- (p-chloroanilino) -3
-Methyl-6-diethylaminofluoran, 2- (p-
Fluoroanilino) -3-methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6- (N-
(P-tolyl) -N-ethylamino) fluoran, 2-
(P-toluidino) -3-methyl-6-diethylaminofluoran, 2- (o-chloroanilino) -6-dibutylaminofluoran, 2- (o-fluoroanilino)-
6-dibutylaminofluoran, 2-anilino-3-methyl-6-piperidinofluoran, 2-anilino-3-
Methyl-6-pyrrolidinofluoran, 2-ethoxyethylamino-3-chloro-6-diethylaminofluoran, 2-anilino-3-chloro-6-diethylfluoran, 2-chloro-6-diethylaminofluoran, 2 −
Methyl-6-diethylaminofluoran and the like.

As the triarylmethane compound, for example, 3,3-bis (p-dimethylaminophenyl) -6
-Dimethylaminophthalide (alias: crystal violet lactone), 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3- (1,2-dimethylaminoindole-3
-) Isophthalide and the like, as spiropyran-based compounds, for example, 3-methyl-3-spirodinaphthopyran,
1,3,3-trimethyl-6-nitro-8'-methoxyspiro (indoline-2,2'-benzopyran) and the like; diphenylmethane-based compounds such as N-halophenyl-leucouramine and the like; For example, benzoylleucomethylene blue and the like, and as the lactam compound, for example, rhodamine-
Examples of the fluorene compound such as B-anilinolactam include 3,6-bis (dimethylamino) fluorene spiro (9,3 ′)-6′-dimethylaminophthalide and 3,6-bis (dimethylamino). Fluorenspiro (9,3 ')-6'-pyrrolidinophthalide, 3-dimethylamino-6-diethylaminofluorenspiro (9,
3 ′)-6′-pyrrolidinophthalide and the like.

Examples of color-developing compounds that can be used in combination include α-naphthol, β-naphthol, p-octylphenol, 4-t-octylphenol, pt-butylphenol, p-phenylphenol and 1,1'-bisphenol. (P-hydroxyphenyl) propane, 2,2′-bis (p-hydroxyphenyl) propane, 2,2′-bis (p-hydroxyphenyl) butane, 1,1′-bis (p-hydroxyphenyl) cyclohexane, 4,4 '
-Thiobisphenol, 4,4'-cyclo-hexylidene diphenol, 4,4'-dihydroxydiphenyl sulfone, bis (3-allyl-4-hydroxyphenyl)
Sulfone, 2,2'-bis (2,5-dibromo-4-hydroxyphenyl) propane, 4,4'-isopropylidene bis (2-t-butylphenol), 2,2'-methylenebis (4-chlorophenol) , 4-hydroxy-4'-isopropoxydiphenyl sulfone, bis (4
-Phenolic compounds such as -hydroxyphenyl) methyl acetate, bis (4-hydroxyphenyl) butyl acetate, bis (4-hydroxyphenyl) benzyl acetate, benzyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, 4-hydroxyphthalate Acid dibenzyl, dimethyl 4-hydroxydiphthalate, ethyl 5-hydroxyisophthalate, 3,5-di-t-butylsalicylic acid, 3,5-di-
Examples thereof include aromatic carboxylic acid derivatives such as α-methylbenzylsalicylic acid, aromatic carboxylic acids and polyvalent metal salts thereof.

Other additives used as required include, for example, fillers and heat-fusible compounds (sensitizers). Examples of these additives are given below.

Examples of usable fillers are calcium carbonate, magnesium carbonate, magnesium oxide, silica, white carbon, talc, clay, alumina, magnesium hydroxide, aluminum hydroxide, aluminum oxide, barium sulfate, polystyrene resin, Urea-formalin resin and the like.

Examples of heat-fusible compounds that can be used include waxes such as animal and vegetable waxes and synthetic waxes, higher fatty acids, higher fatty acid amides, higher fatty acid anilides, acetylated aromatic amines, naphthalene derivatives and aromatic ethers. Aromatic carboxylic acid derivatives, aromatic sulfonic acid ester derivatives, carbonic acid or oxalic acid diester derivatives, biphenyl derivatives, terphenyl derivatives and the like which are solid at room temperature and have a melting point of about 70 ° C. or higher can be used.

Examples of waxes include wood wax, carnauba wax, shellac, paraffin, montan wax,
Paraffin oxide, polyethylene wax, polyethylene oxide and the like, as higher fatty acids, for example, stearic acid,
Examples of higher fatty acid amides such as behenic acid include stearic acid amide, oleic acid amide, N-methylstearic acid amide, erucic acid amide, methylolbehenic acid amide, methylolstearic acid amide, methylenebisstearic acid amide, and ethylenebisstearin Acid amides and the like, higher fatty acid anilides such as stearic acid anilide and linoleic acid anilide, acetylated aromatic amines such as acetotoluidide, and naphthalene derivatives such as 1-benzyloxynaphthalene, Benzyloxynaphthalene, 1-hydroxynaphthoic acid phenyl ester and the like include aromatic ethers such as 1,2-diphenoxyethane, 1,4
-Diphenoxybutane, 1,2-bis (3-methylphenoxy) ethane, 1,2-bis (4-methoxyphenoxy) ethane, 1,2-bis (3,4-dimethylphenyl) ethane, 1-phenoxy- 2- (4-chlorophenoxy) ethane, 1-phenoxy-2- (4-methoxyphenoxy) ethane and the like include aromatic carboxylic acid derivatives such as benzyl p-hydroxybenzoate,
Examples of aromatic sulfonic acid ester derivatives include benzyl p-benzyloxybenzoate and dibenzyl terephthalate, for example, p-toluenesulfonic acid phenyl ester, phenylmesitylene sulfonate,
-Methylphenyl mesitylenesulfonate and the like are carbonic acid or oxalic acid diester derivatives, for example, diphenyl carbonate, dibenzyl oxalate, dioxalate (4
-Methylbenzyl) ester, oxalic acid di (4-chlorobenzyl) ester and the like, as biphenyl derivatives,
For example, p-benzylbiphenyl, p-allyloxybiphenyl and the like are terphenyl derivatives such as m-
Terphenyl and the like are each exemplified.

In addition, lubricants such as zinc stearate, calcium stearate and aluminum stearate, various surfactants, defoaming agents, ultraviolet absorbers and the like are added as required.

The thermosensitive color-developing composition of the present invention is prepared by the following method using the above-mentioned materials. That is,
According to a conventional method, first, 2- (o-fluoroanilino) -6-diethylaminofluorane or 2- (o-chloroanilino) -6-dimethylaminofluorane, 2,
The 4'-dihydroxydiphenyl sulfone is pulverized and dispersed separately in an organic solvent together with a binder or, if necessary, other additives with a disperser such as a ball mill, attritor, or sand mill, and then described in the present invention. The thermosensitive color-developing composition of the present invention is obtained by mixing in the ratio of the above range.

Next, the heat-sensitive recording material of the present invention will be described. The heat-sensitive recording material of the present invention is obtained by applying the above-described heat-sensitive color-forming composition of the present invention on a support such as paper, plastic film, synthetic paper, or fiber sheet by a conventional method. In this case, the coating can be performed by a normal coating method using a bar coater, a roll coater, a reverse coater, a doctor coater, a microgravure coater, or the like, and printing by a method such as gravure, letterpress, flexo, or silk screen is also possible. . After the application, the organic solvent is dried and removed by a conventional method such as air drying (normal temperature) or hot air drying up to about 150 ° C. to obtain the heat-sensitive recording material of the present invention. The heat-sensitive recording layer is usually formed on the support as a coating film having a dry weight of 0.5 to 20 g / m ² . In the heat-sensitive recording material of the present invention, an overcoat layer of, for example, polyvinyl alcohol can be provided on the heat-sensitive recording layer, if necessary.

2- as a color-forming compound in an organic solvent
(O-Fluoroanilino) -6-diethylaminofluorane or 2- (o-chloroanilino) -6-diethylaminofluorane containing 2,4′-dihydroxydiphenylsulfone as a color-developing compound and a polymer compound. The thermosensitive color-developing composition of the present invention has good coatability or printability and adhesion to paper, plastic film, synthetic paper, etc., and the thermosensitive recording material of the present invention prepared using the composition is It has excellent color development and storage stability.

[0022]

EXAMPLES The present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. still,
In the examples, "part" indicates part by weight.

Example 1 A mixture having the following composition was pulverized for 30 minutes using a sand grinder to obtain solutions [A] and [B], respectively. [A] Liquid: 2- (o-fluoroanilino) -6-diethylaminofluorane 40 parts Toluene 60 parts [B] Liquid: 2,4′-dihydroxydiphenylsulfone 40 parts Toluene 60 parts

Then, the thermosensitive color-forming composition of the present invention was obtained by mixing in the following proportions. [A] liquid 12.5 parts [B] liquid 37.5 parts 20% methyl methacrylate / styrene copolymer (molecular weight = about 100,000) toluene solution 40.0 parts Next, this thermosensitive coloring composition was added. A thermosensitive coloring layer was provided on a white polyester film having a thickness of 188 μm so as to have a dry weight of 6 g / m ² and dried. Further, a 10% PVA aqueous solution was applied on the thermosensitive coloring layer in an amount of 3 g when dried.
It coating dried so that / m ² to obtain a heat-sensitive recording material of the present invention.

Example 2 2- (o-fluoroanilino) -of the liquid [A] of Example 1
A thermosensitive recording material of the present invention was obtained in the same manner as in Example 1 except that 2- (o-chloroanilino) -6-diethylaminofluorane was used instead of 6-diethylaminofluorane.

Example 3 A mixture having the following composition was ground for 30 minutes using a sand grinder to obtain a liquid [C] and a liquid [D]. [C] liquid: 2- (o-fluoroanilino) -6-diethylaminofluorane 25 parts tetralin 75 parts [D] liquid: 2,4'-dihydroxydiphenylsulfone 25 parts tetralin 75 parts

Next, the following ratios were mixed to obtain a thermosensitive color-forming composition of the present invention. Liquid [C] 16 parts [D] Liquid 48 parts 20% Methyl methacrylate / styrene / ethyl acrylate copolymer solution (molecular weight = about 100,000) in toluene 40 parts Next, this thermosensitive coloring composition was applied to a thickness of A thermosensitive coloring layer was provided on a 188 μm white polyester film by coating so that the dry weight would be 6 g / m ² . Further, a 10% PVA aqueous solution was applied on the thermosensitive coloring layer in an amount of 3 g when dried.
It coating dried so that / m ² to obtain a heat-sensitive recording material of the present invention.

Comparative Example 1 The same as Example 1 except that bisphenol A used in Examples of JP-A-1-96271 was used in place of 2,4′-dihydroxydiphenyl sulfone of Example 1. To prepare a thermosensitive color-sensitive composition for comparison, and from this, a thermosensitive color-sensitive sheet for comparison was obtained.

Comparative Example 2 2- (o-fluoronoanilino) -6-diethylaminofluorane of Example 1 was replaced by the crystal violet lactone used in the examples of JP-A 1-96272, except that A thermosensitive color-forming composition for comparison was prepared in the same manner as in Example 1, and then a thermosensitive color-forming sheet for comparison was obtained. The following quality test was carried out using the heat-sensitive recording material of the present invention and the heat-sensitive color-developing sheet for comparison obtained as described above.

[0030]

[Table 1] Table 1 Quality performance test Background 1) Color density 2) Plasticizer resistance 3) Oil resistance 4) Example 1 0.05 1.50 1.48 1.49 Example 2 0.05 1. 49 1.46 1.47 Example 3 0.05 1.60 1.58 1.58 Comparative Example 1 0.30 1.44 0.44 0.50 Comparative Example 2 0.74 1.46 1.10 1 .15

1) Background: The undeveloped portion of the thermosensitive recording material or thermosensitive color-developing sheet thus prepared was subjected to Macbeth reflection densitometer R
Value measured by D-914 type (reflection density). 2) Color density: Macbeth reflection density of a portion printed by a commercially available thermal printer (D-805P, manufactured by Ishida Koki). 3) Plasticizer resistance: Macbeth reflection density after leaving the plastic eraser at a temperature of room temperature for 48 hours with a pressure of 100 to 200 g / cm ² applied to the portion printed by the printer. 4) Oil resistance: Macbeth reflection density after applying cottonseed oil to a portion printed by the above printer and wiping it after 10 seconds and leaving it to stand for 24 hours.

As is clear from the above quality performance test table, the heat-sensitive recording material produced by using the heat-sensitive color forming composition of the present invention has little background fog and has good image stability such as color density, plasticizer resistance and oil resistance. (Preservation) is excellent.

[0033]

EFFECTS OF THE INVENTION A heat-sensitive color recording material (sheet) having little background fog and excellent in color density and storability was easily obtained.

Claims (5)

[Claims] 1. A thermosensitive color-forming composition comprising a color developing compound, a color forming compound which reacts with the color developing compound under heating to form a color, and a polymer compound in an organic solvent. 2- (o-fluoroanilino) -6- as a coloring compound
A thermosensitive coloring composition comprising diethylaminofluorane or 2- (o-chloroanilino) -6-diethylaminofluorane as the color-developing compound, 2,4′-dihydroxydiphenyl sulfone. 2. The thermosensitive coloring composition according to claim 1, wherein the organic solvent is a hydrocarbon-based organic solvent. 3. The thermosensitive coloring composition according to claim 2, wherein the hydrocarbon organic solvent is liquid at room temperature. 4. The thermosensitive coloring composition according to claim 3, wherein the hydrocarbon organic solvent which is liquid at normal temperature is an aromatic hydrocarbon, a naphthenic hydrocarbon or a paraffin hydrocarbon. 5. A thermosensitive recording material obtained by applying the thermosensitive coloring composition according to any one of claims 1 to 4 on a support and drying.