JP2002120463A - Heat-sensitive coloring composition and heat-sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-sensitive coloring composition in order to provide a heat-sensitive recording material which is excellent in coloring property and preservation property. SOLUTION: For this heat-sensitive coloring composition in an organic solvent, a developing compound, a coloring compound which colors by reacting with the developing compound under a heated state, and a polymeric compound are dispersed. In such a heat-sensitive coloring composition, 5-methylresorcinol is contained as the developing compound. Also, this heat-sensitive recording material is constituted by applying the heat-sensitive coloring composition on a supporting body and drying it.

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 a thermosensitive coloring composition of an organic solvent dispersion type having excellent coloring properties and preservability, and a thermosensitive recording material obtained by coating and drying the composition.

[0002]

2. Description of the Related Art In general, 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, and then adding a binder, a sensitizer, a filler, Additives such as lubricants are added to make a coating liquid and 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 coloring the heat-sensitive 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 field such as calculators, medical field. It is widely used in the field of recorders for measurement, the field of automatic ticket vending machines, the field of heat-sensitive 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 heat-sensitive recording materials has also changed from one-time use (recording) to one that can withstand many uses. The use of plastic films and synthetic papers having good strength and water resistance has been increasing.

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 no satisfactory heat-sensitive recording characteristics have been found, particularly the background fogging and color sensitivity, as well as the resistance to plasticizers and oils.

[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 thermosensitive recording material for forming a thermosensitive coloring recording layer having less background fog, 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 heat-sensitive color-forming composition obtained by dispersing a color-developing compound, a color-forming compound that reacts with the color-developing compound under heating, and a polymer compound in an organic solvent. Wherein the thermosensitive color-forming composition contains 5-methylresorcin as the color-developing compound, and (2) the thermosensitive color-forming composition according to (1), wherein the organic solvent is a hydrocarbon-based organic solvent. (3) The thermosensitive coloring composition according to (2), wherein the hydrocarbon-based organic solvent that is liquid at normal temperature is an aromatic hydrocarbon, a naphthenic hydrocarbon, or a paraffinic hydrocarbon, (4) (1) to ( The present invention also relates to a thermosensitive recording material obtained by applying the thermosensitive coloring composition according to any one of the above 3) on a support and drying.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The heat-sensitive color-forming composition of the present invention is prepared by adding 5-methylresorcin and a polymer compound as a color-forming compound and a color-developing compound in an organic solvent, and other additives as necessary. Are mixed and dispersed. In the thermosensitive color-forming composition of the present invention, the color-forming compound and 5-
Methylresorcin, as a total amount of both, is usually 10% in the total solid content (component excluding the organic solvent) of the thermosensitive coloring composition.
To 90% by weight, preferably 30 to 80% by weight, and the polymer compound is usually 1 to 70% by weight, preferably 10 to 40% by weight. -30% by weight. In a further preferred embodiment, among the above-described compositions, the ratio of the color-forming compound to the color-developing compound is not more than one.
5-Methylresorcin is usually 1 to 10 parts by weight.
Parts by weight, preferably 1 to 5 parts by weight. In addition, 5-methylresorcin was obtained from CAS No. It is a known compound registered in Chemical Abstracts as 504-15-4.

[0008] Examples of the organic solvent used in the present invention include hydrocarbon solvents such as aromatic hydrocarbons, naphthenic hydrocarbons, and paraffinic hydrocarbons, and preferably hydrocarbon solvents which are liquid at room temperature. Specific examples of the aromatic hydrocarbon which is liquid at room 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. Specific examples of naphthenic hydrocarbons that are liquid at room temperature include cyclopentane, methylcyclopentane, 1,1-dimethylcyclopentane, 1,3
-Dimethylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, 1,2,4-trimethylcyclohexane and the like, and a mixture thereof, among which cyclohexane and / or ethylcyclohexane is preferred. Specific examples of the paraffinic hydrocarbon liquid at room temperature include n-hexane and n-hexane.
Examples include heptane, n-octane, n-nonane, or isomers thereof, or a mixture thereof. This amount is usually 50 to 1000% by weight based on the total amount of solids,
Preferably, it is about 100 to 500% by weight. These solvents may be used alone or as a mixture.

The polymer compound is used as a binder, and a compound which is soluble in an organic solvent to be used and has a film-forming property is used. Specific examples thereof include polyvinyl chloride, polystyrene resin, acrylic resin, acrylic styrene copolymer, polyester resin, polycarbonate resin, polyurethane resin, polybutyral resin, epoxy resin, furan resin, vinyl toluene copolymer, and rosin ester resin. And the like. These polymer compounds are usually present in an amount of 1 to 70% by weight, preferably 10 to 4% by weight, based on the total solid content of the composition.
0% by weight is contained.

Examples of the coloring compound used in the heat-sensitive coloring layer are not particularly limited as long as they are generally used in pressure-sensitive recording paper or heat-sensitive recording paper. Specific examples include, for example, fluoran compounds, triarylmethane compounds, spiro compounds, diphenylmethane compounds,
Thiazine-based compounds, lactam-based compounds, fluorene-based compounds and the like can be mentioned.

Among these, specific examples of the fluoran compounds include, for example, 3-diethylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-
7-anilinofluoran, 3- (N-methyl-N-cyclohexylamino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-N-isopentylamino)-
6-methyl-7-anilinofluoran, 3-isobutylethylamino-6-methyl-7-anilinofluoran,
3- (N-ethyl-N-ethoxypropylamino) -6
-Methyl-7-anilinofluoran, 3- (N-methyl-N-hexylamino) -6-methyl-7-anilinofluoran, 3-dipentylamino-6-methyl-7-anilinofluoran, 3- (N-methyl-N-propylamino) -6-methyl-7-anilinofluoran, 3-
(N-ethyl-N-tetrahydrofurylamino) -6
Methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (p-chloroanilino) fluoran, 3-diethylamino-6-methyl-7- (p-fluoroanilino) fluoran, 3- (p- Toluidinoethylamino-6-methyl-7-anilinofluoran, 3-
Diethylamino-6-methyl-7- (p-toluidino)
Fluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-diethylamino-6-chloro-7-
Ethoxyethylaminofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-diethylamino-7- (o-chloroanilino) fluoran, 3-
Dibutylamino-7- (o-chloroanilino) fluoran, 3-diethylamino-7- (o-fluoroanilino) fluoran, 3-dibutylamino-7- (o-fluoroanilino) fluoran, 3-diethylamino-7-
(3,4-dichloroanilino) fluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-6-chloro-7-methylfluoran, 3-diethylamino-7-methylfluoran, 3-diethylamino-7
-Octylaminofluoran, 3-diethylamino-7
-Phenylfluorane, 3- (p-toluidinoethylamino) -6-methyl-7-phenethylfluoran, and the like.

Specific examples of triarylmethane compounds include, for example, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone or CVL), Bis (p-dimethylaminophenyl) phthalide, 3- (p-
Dimethylaminophenyl) -3- (1,2-dimethylaminoindole-3-) isophthalide, 3- (p-dimethylaminophenyl) -3- (2-methylindole-
3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-phenylindol-3-yl) phthalide, 3,3-bis (1,2-dimethylindole-3)
-Yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,3-bis (9-ethylcarbazol-3-yl) ) -5-dimethylaminophthalide,
3,3- (2-phenylindol-3-yl) -5
Dimethylaminophthalide, 3-p-dimethylaminophenyl-3- (1-methylpyrrol-2-yl) -6-dimethylaminophthalide and the like.

Further, specific examples of spiro compounds include:
For example, 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3′-dichlorospirodinaphthopyran, 3-benzylcipirodinaphthopyran, 3-propylspirobenzopyran, 3-methylnaphtho- (3-
Methoxybenzo) spiropyran, 1,3,3-trimethyl-6-nitro-8'-methoxyspiro (indoline-
2,2′-benzopyran) and the like are specific examples of diphenylmethane-based compounds, for example, N-halophenyl-leuco auramine, 4,4-bis-dimethylaminophenylbenzhydryl benzyl ether, N-2,4,5 -Specific examples of thiazine compounds include benzoyl leucomethylene blue and p-nitrobenzoyl leucomethylene blue, and specific examples of lactam compounds include rhodamine B anilino lactam and rhodamine B. Specific examples of the fluorene-based compound include, for example, 3,6-bus (dimethylamino) fluorenespiro (9,3 ′)-6′-dimethylaminophthalide, Bis (dimethylamino) fluorenespiro (9,3 ')-6'-pi Rijinofutarido, 3-dimethylamino-6-diethylamino fluorene spiro (9,
3 ′)-6′-Pyrrolidinophthalide and the like. These coloring compounds are used alone or in combination.

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

Specific examples of fillers that can be used include calcium carbonate, magnesium carbonate, magnesium oxide, silica, white carbon, talc, clay, alumina,
Examples include magnesium hydroxide, aluminum hydroxide, aluminum oxide, barium sulfate, polystyrene resin, acrylic resin, polyolefin resin, benzoguanamine resin, melamine resin, and urea-formalin resin.

Specific 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 the like. Aromatic ethers, aromatic carboxylic acid derivatives, aromatic sulfonic acid ester derivatives, carbonic acid or oxalic acid diester derivatives, biphenyl derivatives, terphenyl derivatives, etc.
Those which are solid at normal temperature and have a melting point of about 70 ° C. or more can be used.

Specific examples of waxes include wood wax, carnauba wax, shellac, paraffin, montan wax, paraffin oxide, polyethylene wax, polyethylene oxide, and the like. Specific examples of higher fatty acids include, for example, stearic acid and behenic acid. Specific examples of higher fatty acid amides include, for example, stearic acid amide, oleic acid amide, N-methylstearic acid amide, erucic acid amide, methylolbehenic acid amide, methylolstearic acid amide, methylenebisstearic acid amide, ethylenebisamide Specific examples of stearic acid amides and higher fatty acid anilides include, for example, stearic acid anilide and linoleic acid anilide, and specific examples of acetylated aromatic amines include, for example, acetotoluizide.

Further, specific examples of the naphthalene derivative include:
For example, 1-benzyloxynaphthalene, 2-benzyloxynaphthalene, 1-hydroxynaphthoic acid phenyl ester and the like are specific examples of aromatic ethers, for example, 1,2-diphenoxyethane, 1,4-diphenoxybutane, , 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-
Specific examples of aromatic carboxylic acid derivatives include phenoxy-2- (4-methoxyphenoxy) ethane and the like, for example, benzyl p-hydroxybenzoate, benzyl p-benzyloxybenzoate, dibenzyl terephthalate and the like. Specific examples of the aromatic sulfonic acid ester derivatives include, for example, p-toluenesulfonic acid phenyl ester, phenyl mesitylene sulfonate,
Specific examples of carbonic acid or oxalic acid diester derivatives include, for example, diphenyl carbonate, dibenzyl oxalate, di (4-methylbenzyl) oxalate, and di (4-methyl oxalate).
Chlorobenzyl) ester and the like, specific examples of the biphenyl derivative include, for example, p-benzylbiphenyl and p-allyloxybiphenyl, and specific examples of the terphenyl derivative include, for example, m-terphenyl.

Other additives such as lubricants such as zinc stearate, calcium stearate, and aluminum stearate, various surfactants, defoamers, and ultraviolet absorbers are added as required.

The thermosensitive coloring composition of the present invention is prepared using the above-mentioned materials by, for example, the following method. That is,
First, the color-forming compound and 5-methylresorcinol are separately pulverized and dispersed in an organic solvent together with a binder or other additives as necessary using a dispersing machine such as a ball mill, an attritor, or a sand mill. After that, the mixture is usually mixed in the ratio described in the present invention to obtain the thermosensitive coloring composition of the present invention.

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 (protective layer) of, for example, polyvinyl alcohol can be provided on the heat-sensitive recording layer, if necessary.

The heat-sensitive coloring composition of the present invention comprising a coloring compound, 5-ethylresorcin as a developing compound and a polymer compound in an organic solvent is useful for producing paper, plastic film, synthetic paper and the like. The coatability, printability, and adhesiveness are good, and the heat-sensitive recording material of the present invention prepared using this has excellent characteristics in color development and storage.

[0023]

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, "parts" indicates parts by weight.

Example 1 A mixture having the following composition was pulverized for 30 minutes using a sand grinder to prepare a solution [A] and a solution [B], respectively. [A] solution: 3-diethylamino-7- (o-fluoroanilino) fluoran 40 parts ethylcyclohexane 60 parts [B] solution: 5-methylresorcin 40 parts ethylcyclohexane 60 parts

Next, the mixture is mixed in the following ratio to obtain the thermosensitive coloring composition of the present invention. [A] solution 12.5 parts [B] solution 37.5 parts 25% butyl methacrylate / styrene copolymer (molecular weight = about 100,000) toluene solution 40.0 parts Next, this thermosensitive coloring composition was A thermosensitive coloring layer is provided on a 188 μm-thick white polyester film so as to have a dry weight of 6 g / m ² and dried. Further, a coating liquid for a protective layer having the following ratio is applied and dried on the above-mentioned thermosensitive coloring layer so that the coating amount at the time of drying is 3 g / m ² to obtain a thermosensitive recording material of the present invention having a protective layer. 40% styrene / acrylate copolymer emulsion 20 parts 5% bentonite aqueous dispersion 40 parts 30% zinc stearate aqueous dispersion 3 parts

Example 2 In place of 3-diethylamino-7- (o-fluoroanilino) fluoran of Example 1, 3-diethylamino-7
Example 1 using-(o-chloroanilino) fluoran
To obtain a heat-sensitive recording material of the present invention having a protective layer.

Example 3 A mixture having the following composition was pulverized for 30 minutes using a sand grinder to prepare a solution [C] and a solution [D], respectively. [C] Solution: 3-diethylamino-7- (o-fluoroanilino) fluoran 25 parts Naphtha (boiling point 154-197 ° C) 75 parts [D] Solution: 5-methylresorcin 25 part Naphtha (boiling point 154-197 ° C) 75 parts

Next, the mixture is mixed at the following ratio to obtain the thermosensitive coloring composition of the present invention. [C] solution 16 parts [D] solution 48 parts 20% methyl methacrylate / styrene copolymer (molecular weight = about 100,000) ethyl toluene solution 40 parts Next, this thermosensitive coloring composition was white with a thickness of 188 μm. A thermosensitive coloring layer is provided on a polyester film by applying and drying so that the dry weight is 6 g / m ² . Further, a protective layer is provided on the thermosensitive coloring layer in the same manner as in Example 1 to obtain a thermosensitive recording material of the present invention having a protective layer.

Comparative Example 1 A comparative thermosensitive coloring composition was prepared in the same manner as in Example 1 except that bisphenol A was used instead of 5-methylresorcin in Example 1, and then a thermosensitive composition for comparison was prepared. A coloring sheet is obtained.

Table 1 shows the quality performance test results of the heat-sensitive recording material of the present invention and the heat-sensitive coloring sheet for comparison obtained as described above.

Table 1 Quality performance test Ground 1) Color density 2) Plasticizer resistance 3) Oil resistance 4) Example 1 0.07 1.54 1.51 1.52 Example 2 0.06 1.55 1.55 1.56 Example 3 0.07 1.55 1.55 1.57 Comparative Example 1 0.13 1.40 0.38 0.40

1) Background: A value (reflection density) obtained by measuring an uncolored portion of the produced thermosensitive coloring sheet with a Macbeth reflection densitometer RD-914. 2) Color density: Macbeth reflection density of a portion printed by a commercially available thermal printer (D-805P, manufactured by Ishida). 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-mentioned quality performance test table, the heat-sensitive recording material prepared by using the heat-sensitive color-forming composition of the present invention has little background fog, and is excellent in color density, plasticizer resistance, oil resistance and the like. I have.

[0034]

According to the present invention, a heat-sensitive color recording material (sheet) having less background fog and excellent color density and storage stability can be easily obtained.

Claims (4)

[Claims] 1. A heat-sensitive coloring composition comprising a color developing compound, a color developing compound which reacts with said color developing compound under heating and develops a color in an organic solvent, and a polymer compound, wherein said color developing compound is A thermosensitive color-forming composition comprising 5-methylresorcin as a hydrophilic compound. 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 organic solvent is an aromatic hydrocarbon, a naphthenic hydrocarbon or a paraffinic hydrocarbon. 4. A thermosensitive recording material obtained by applying the thermosensitive coloring composition according to claim 1 on a support and drying.