JP3019280B2 - Thermosensitive coloring composition and thermosensitive recording material obtained by applying the same - Google Patents

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 a thermosensitive recording material obtained by applying 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, and a filler. A coating liquid is formed by adding additives such as lubricants, and is applied to paper, film, synthetic paper, etc., and one or both of the leuco dye and the developer are melted by heating, due to a chemical reaction occurring upon contact. A color recording record is obtained. For color development of such a heat-sensitive recording sheet, a thermal printer or the like having a built-in thermal head is used. 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 support for heat-sensitive recording materials is also made of paper, such as mechanical strength and water resistance. The conversion to a plastic film or synthetic paper having a good quality is desired.

Conventionally, a thermosensitive coloring composition (ink or paint, etc.) used for forming a thermosensitive coloring 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 that are essential, especially background fogging and color sensitivity.

[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 fog and excellent coloring density.

[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 provides a thermosensitive coloring composition in which a color-developing compound and a color-forming compound that reacts with the color-developing compound under heating to form a color are dispersed in a vehicle mainly composed of an organic solvent and a polymer compound. The compound contains a compound of the following formula (1) as the color-forming compound, a compound of the following formula (2) as the color-developing compound, and further contains a compound of the following formula (3). And a heat-sensitive recording material obtained by applying the composition.

[0007]

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[0008]

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[0009]

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The present invention will be described in detail. The heat-sensitive color-forming composition of the present invention comprises a color-forming compound of the above formula (1), i.e., 2-o-fluoroanilino-6-diethylaminofluoran and a color-developing compound of the formula (2) in an organic solvent. That is,
4,4'-sulfonyl-bis (2-allylphenol)
And the compound of formula (3), i.e., 2- (2'-hydroxy-
It is obtained by mixing and dispersing 5'-t-octylphenyl) -benzotriazole as a main component together with a polymer compound shown below and other additives as required. The ratio in the thermosensitive coloring composition is 1 to 10 parts by weight, preferably 1 to 5 parts by weight of the coloring compound of the formula (2) based on 1 part by weight of the coloring compound of the formula (1). , The compound of formula (3) is preferably 0.5 to 10 parts by weight,
0.5 to 5 parts by weight are each suitable.

An organic solvent for preparing the composition of the present invention,
Specific examples of the polymer compound, the color-forming compound that can be used in combination, the color-developing compound, and other additives are as follows.

As the organic solvent for forming the vehicle, aromatic hydrocarbons, naphthenic hydrocarbons, and paraffinic hydrocarbons may be used alone or as a mixture. Examples of the aromatic hydrocarbon 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 include cyclopentane, methylcyclopentane, 1,1-dimethylcyclopentane, 1,3-dimethylcyclopentane, cyclohexane, ethylcyclohexane, 1,2,4-trimethylcyclohexane, and the like, or a mixture thereof. Of these, it is preferable to use cyclohexane and / or ethylcyclohexane. Examples of the paraffinic hydrocarbon include n-hexane, n-heptane, n-octane, n-nanone, or an isomer thereof, or a mixture thereof.

As the polymer compound serving as a binder, those which are soluble in the organic solvent to be used and give vehicle formation and film formation are used. Specific examples thereof include polyvinyl chloride, polyacryl, polyacryl styrene copolymer, polyester, polycarbonate, polyurethane, polybutyral, epoxy resin, furan resin, vinyl toluene copolymer rosin ester resin, and the like. These polymer compounds are used in an amount of 1 to 20% by weight, preferably 3 to 10%.
% By weight is contained in the composition.

The following are examples of color-forming compounds that can be used in combination. Fluoran compounds, triarylmethane compounds, spiropyran compounds, diphenylmethane compounds, thiazine compounds, lactam compounds,
Examples thereof include fluorene compounds, and specific examples thereof include the following compounds. Fluoran compounds; 2-aniline-3-methyl-6
Diethylaminofluoran, 2-anilino-3-methyl-6- (N-methyl-N-cyclohexylamino) fluoran, 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- (p-toluidinoethylamino) 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-pyrroli Dinofluoran, 2-ethoxyethylamino-3-chloro-6-diethylaminofluoran, 2-anilino-3-chloro-6-diethylfluoran, 2-chloro-6-diethylaminofluoran, 2-methyl-6 Such as diethylaminofluoran,

Triarylmethane compounds; 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone), 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3-
Spiropyran compounds such as (1,2-dimethylaminoindole-3-) isophthalide; 3-methyl-3-spirodinaphthopyran, 1,3,3-trimethyl-6-nitro-
Diphenylmethane compounds such as 8'-methoxyspiro (indoline-2,2'-benzopyran); N-halophenyl-leuco auramine; thiazine compounds; lactam compounds such as benzoyl leucomethylene blue; rhodamine-B-anilinolactam Fluorene compounds; 3,6-Bus (dimethylamino)
Fluorene spiro (9,3 ')-6'-dimethylaminophthalide, 3,6-bis (dimethylamino) fluorene spiro (9,3')-6'-pyrrolidinophthalide, 3-
Dimethylamino-6-diethylaminofluorenespiro (9,3 ')-6'-pyrrolidinophthalide

The following are examples of color developing compounds that can be used in combination. α-naphthol, β-naphthol, p-octylphenol, 4-t-octylphenol, pt-butylphenol, p-phenylphenol, 1,1′-bis (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-hexylidenediphenol, 4,4'-sulfonyldiphenol, 2,2'-bis (2,5-dibromo-4-hydroxyphenyl) propane, 4,4'-isopropylidenebis (2-t-butylphenol ), 2,
Phenolic compounds such as 2'-methylenebis (4-chlorophenol), benzyl p-hydroxybenzoate, p
-Ethyl hydroxybenzoate, dibenzyl 4-hydroxyphthalate, dimethyl 4-hydroxydiphthalate, ethyl 5-hydroxyisophthalate, 3,5-di-t-butylsalicylic acid, 3,5-di-α-methylbenzylsalicylic acid, etc. Examples thereof include aromatic carboxylic acid derivatives, aromatic carboxylic acids and polyvalent metal salts thereof.

Other examples of additives used as needed are given below.

Examples of usable fillers include 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 the heat-fusible compound that can be used include waxes such as animal and plant waxes, polyethylene waxes and synthetic waxes, higher fatty acids, higher fatty acid amides, higher fatty acid metal salts, acetylated compounds of aromatic amines, and aromatic amines. Examples include ether compounds and biphenyl derivatives which are solid at ordinary temperature and have a melting point of about 80 ° C. or higher. In addition, lubricants such as zinc stearate, calcium stearate, and aluminum stearate, various surfactants, antifoaming agents, and the like are added as needed.

The thermosensitive coloring composition of the present invention is prepared using the above-mentioned materials by, for example, the following method. First, a color-forming compound of the above formula (1),
A color developing compound of the formula (3) in an organic solvent,
After separately pulverized and dispersed in a dispersing machine such as a ball mill, an attritor, and a sand mill together with a binder or other additives as necessary, and then mixed at a ratio within the range described in the present invention, the thermosensitive coloring composition Get things. Equation (3)
In some cases, the compound of formula (1) may be used simultaneously with the color-forming compound of formula (1) or the color-developing compound of formula (2).

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 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 coating, the organic solvent is dried and removed by a conventional method to obtain the heat-sensitive recording material of the present invention. The heat-sensitive recording layer is usually 0.5 to
It is formed on a support as a coating film of 20 g / m ² .

The present invention comprises a vehicle mainly comprising an organic solvent and a polymer compound containing the color-forming compound of the formula (1), the color-developing compound of the formula (2) and the compound of the formula (3). The heat-sensitive coloring composition of the present invention has good coatability or printability and adhesion to paper, plastic film, synthetic paper, etc., and the heat-sensitive recording material of the present invention prepared by using the same has good coloring properties. In addition to being excellent in ruggedness, there is a feature that the background fog is small.

[0023]

EXAMPLES The present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. 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 obtain a liquid [A] and a liquid [B]. [A] solution: 2-o-fluoroanilino-6-diethylaminofluoran 40 parts toluene 60 parts [B] solution: 4,4'-sulfonyl-bis (2-allylphenol) 40 parts toluene 60 parts

Then, they were mixed in the following proportions to obtain a thermosensitive coloring composition of the present invention. [A] solution 12.5 parts [B] solution 37.5 parts 25% 2- (2'-hydroxy-5'-t-octylphenyl) -benzotriazole toluene solution 10.0 parts 20% methyl methacrylate 40.0 parts of a toluene solution of a styrene copolymer (molecular weight = about 100,000) Next, this thermosensitive coloring composition was applied on a milky white polyester film having a thickness of 188 μm so as to have a dry weight of 6 g / m ^2. After drying, the heat-sensitive recording material of the present invention was obtained.

Example 2 A mixture having the following composition was ground with a sand grinder for 30 minutes to obtain a solution [C] and a solution [D], respectively. [C] solution: 2-o-fluoroanilino-6-diethylaminofluoran 25 parts tetralin 75 parts [D] solution: 4,4'-sulfonyl-bis- (2-allylphenol) 20 parts 2- (2 '-Hydroxy-5'-t-octylphenol) 7 parts Tetraline 73 parts

Then, the mixture was mixed at the following ratio to obtain a thermosensitive coloring composition of the present invention. [C] solution 16 parts [D] solution 60 parts 20% methyl methacrylate / styrene / ethyl acrylate copolymer (molecular weight = about 100,000) toluene solution 40 parts tetralin 34 parts Next, this thermosensitive coloring composition Was applied onto a milky white polyester film having a thickness of 188 μm so as to have a dry weight of 7 g / m ² and dried to obtain a heat-sensitive recording material of the present invention.

Comparative Example 1 A comparative thermosensitive coloring composition was prepared in the same manner as in Example 1 except that 2- (2'-hydroxy-5'-t-octylphenyl) -benzotriazole was not used. Then, a thermosensitive coloring sheet for comparison was prepared.

Comparative Example 2 A thermosensitive coloring composition for comparison was prepared in the same manner as in Example 1 except that bisphenol A was used instead of 4,4'-sulfonyl-bis (2-allylphenol). Was prepared, and a thermosensitive coloring sheet for comparison was obtained.

COMPARATIVE EXAMPLE 3 Instead of 2-o-fluoronoanilino-6-diethylaminofluoran of Example 1, 2-anilino-3-methyl-
A thermosensitive coloring composition for comparison was prepared in the same manner as in Example 1 except that 6-diethylaminofluoran was used, and a thermosensitive coloring sheet for comparison was obtained. Using the heat-sensitive recording material of the present invention obtained as described above and a heat-sensitive coloring sheet for comparison, the following quality tests were carried out.

[0031]

1) Background: A value (reflection density) obtained by measuring an uncolored portion of the sample with a Macbeth reflection densitometer RD-914. 2) Color density: Using a hot plate at a printing pressure of 1 kg / cm ² ,
Macbeth reflection density when pressed against a sample for 5 seconds at each of the above temperatures.

As is clear from the above-mentioned quality performance test table, the heat-sensitive recording material prepared using the heat-sensitive color-forming composition of the present invention has less background fogging and excellent color density.

[0034]

According to the present invention, a heat-sensitive recording material having less background fog and excellent color developability was obtained.

Claims (2)

(57) [Claims] 1. A thermosensitive coloring composition obtained by dispersing a color-developing compound and a color-forming compound which reacts with the color-developing compound under heating and forms a color in a vehicle mainly comprising an organic solvent and a polymer compound. In the above, the color-forming compound represented by the following formula (1)
And a compound of the following formula (2) as a color-developing compound, and a compound of the following formula (3). Embedded image Embedded image Embedded image 2. A thermosensitive recording material obtained by coating the thermosensitive coloring composition according to claim 1 on a support.