JPS60105587A - Two-color thermal recording material - Google Patents

Abstract

PURPOSE:To enhance a color separating property, by successively laminating a high temp. color forming layer containing a leuco dye and a phenolic compound, an intermediate layer containing an aliphatic amine color erasing agent and a low temp. color forming layer containing the leuco dye and a thiourea derivative onto a support. CONSTITUTION:A high temp. color forming layer containing a leuco dye and a phenolic compound is formed onto a support and an intermediate layer containing thermoplastic aliphatic amine as a color erasing agent is provided thereon. Further, a low temp. color forming layer containing a thiourea derivative represented by formula (wherein R1 and R2 are hydrogen, halogen a trifluoromethyl group and an 1-4C alkyl group) is laminated onto the intermediate layer to form a two-color thermal recording material. As the aforementioned leuco dye, a leuco compound of a dye belonging to a trifluoromethane type, a fluorane type, a phenothiazine type, an auramine type and a spiropyran type is pref.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a leuco two-color heat-sensitive recording material.

[Prior art]

A thermosensitive recording material is a material in which a thermosensitive coloring layer capable of forming a colored image by heating is provided on a support such as paper, and a thermal printer equipped with a thermal head is widely used for heating.

These conventional heat-sensitive recording materials include a colorless or light-colored leuco dye (color-forming main agent) having a lactone ring, lactam ring, spiropyran ring, etc. in the heat-sensitive coloring layer, and a color developer that develops color by reacting with this leuco dye when heated. Agent (color development aid)
Those containing these are widely used because they have clear color tones and less fogging.

By the way, heat-sensitive recording materials can easily produce colored images just by heating them, so they are not only used for copying books, documents, etc., but also for recording various types of information such as electronic computers, facsimiles, telex machines, and recording the output of measuring machines. However, depending on the purpose of recording, in order to display particularly necessary data or numbers more clearly, it is possible to record by changing the color of that part (display color) from the color of other parts. Of course, it is desirable to be able to do so.

Recently, attempts have been made to obtain multicolor recording by utilizing differences in heating temperature or thermal energy, and various multicolor thermosensitive recording papers have been proposed accordingly. Multi-color thermosensitive recording paper is generally formed by stacking two types of high-temperature and low-temperature coloring layers that develop different tones with different coloring heat energies on a support, and can be broadly classified into the following two types: Divided into types. One of them is that when coloring a high-temperature coloring layer, the color is mixed with the color tone of the coloring layer at low d1 to obtain a color tone different from the coloring tone of the low-temperature coloring layer.
One is high! ! When coloring the coloring layer, a decoloring agent that decolorizes the low temperature coloring layer is used to obtain only the color tone of the high 1111 coloring layer without color mixing of the coloring tone of the low temperature coloring layer. As a specific example of these, the former is the Tokko Sho 4! ]
-69 Publication, Special Publication No. 49-43/12, Special Publication No. 4r
]-2゛77oH report, JP-A-48-86543,
The latter is described in Japanese Patent Publication No. 17865, No. 17866, Japanese Patent Publication No. 51-2f1024, etc.
Publication No. 1987-87542, Japanese Patent Publication No. 1987-87542
These are disclosed in Japanese Patent Application Laid-Open No. 18048, Japanese Patent Application Laid-open No. 53-47843, and the like.

However, in the case of the former multicolor thermosensitive recording paper,
During high-temperature coloring, the color tones that can be specifically achieved are limited to black threads that have a strong high-temperature coloring tone, such as red-black, blue-black, etc., in order to mix the color with the color tone of the low-temperature coloring layer. There is a drawback. On the other hand, in the case of the latter multicolor thermosensitive recording paper, the combination of color tones can be freely selected, but when coloring at high temperatures, high aliphatic alcohols, polyethers, Polyethylene glycol derivatives, acetamide, stearamide, phthalonitrile as nitrogen-containing organic compounds, guanidine derivatives as amine derivatives, etc. have been proposed, but in the conventional configuration, when coloring at a high temperature, not only a low-temperature coloring layer but also a high-temperature coloring layer is used. There was also a drawback that the layer had a decoloring effect and became unclear. In addition, the color tone is two combinations such as (blue-red), (green-red), etc.
Most of them are colored thermal paper, and no (black-red) combination has been proposed.

[Objective] The object of the present invention is to provide an L1 iso-based two-color thermosensitive recording material in which color separation Al1 is improved and color mixture does not occur in high-temperature color images.

〔composition〕

That is, according to the present invention, three layers are laminated in this order on a support: a high-temperature coloring layer, an intermediate layer containing a decolorizing agent, and a low-temperature coloring layer, and the high-temperature coloring layer contains a leuco dye and a phenol. The intermediate layer contains a thermo-'iMd+ aliphatic amine as a decolorizing agent, and the low-temperature coloring layer contains a leuco dye and a thiourea derivative represented by the following general formula (A). A two-color heat-sensitive recording monthly fee featuring:

General formula (A): (In the formula, It, , R2 is hydrogen, halogen, trifluoromethyl group, or alkyl group having 1 to 4 carbon atoms) In the present invention, the aliphatic amine used as a decolorizing agent is , as long as it is thermofusible with a melting point of 45 to 200°C, and specific examples thereof include distearylamine, triethylenediamine, octamethylenediamine,
Di-n-dodecylamine.

Examples include stearylamine and behenylamine.

Further, as specific examples of the thiourea derivative as a color developer represented by the general formula (A), for example, N,N'-diphenylthiourea, N-p-ethylphenyl-N'-phenylthiourea, N- p-Butylphenyl-N'-phenylthiourea, N,N'-di-m-chlorophenylthiourea, N,N'-di-m-chlorophenylthiourea, N
, N'-di-m-trifluoromethylphenylthiourea, N,N'-di-m-methylphenylthiourea, and the like.

On the other hand, examples of the color developer to be contained in the high temperature coloring layer include 4-hydroxyphenoxide, 4=-t-butylphenol, 4-hydroxyacetophenone, resorcinol, α-naphthol, thymol, β-naphthol, catechol, hydroquinone, Pyrogallol, phloroglucin, phloroglucin carboxylic acid, 4.4'-5ee-butylidene diphenol, /1.4'-isopropylidene-bis(2-butylphenol), /I-t,
-Octylcatechol 4'-sec-butylidene diphenol, 2,2'-dihydroxydiphenyl, 2,2'
-methylene-bis(4-methyl-[j-butylphenol), 2,2-bis(4'-ogycyphenyl)
Examples include propane (also known as bisphenol A), 3,5-xylenol, and the like.

J-? The leuco dyes used in this method can be applied singly or in combination of two or more types, and the leuco dyes used in this type of heat-sensitive materials include the following:
For example, leuco compounds of triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, and spiropyran-based dyes are preferably used. Specific examples of such leuco dyes include those shown below.

3,3-bis(p-dimethylaminophenyl)-phthalide, 3,3-bis(1]-dimethylaminophenyl)-6-
Cyphtylaminophthalide (also known as crystal violet lactone), 3,3-bis(p-dimethylaminophenyl)-6-dibutylaminophenyl, 3,3-bis(p-dimethylaminophenyl)-6-chlorphthalide, 3, 3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlorofluorane, 3-dimethylamino-5,7-cyphthylfluorane, 3
-diethylamino-7,8-benzfluorane, 3-(
N-p-tolyl-N-ethylamino)-6-methyl-7
-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2- (N-(3'-trifluoromethylphenyl)
amino)-6-ethylaminofluorane, 2-(3
, 6-bis(diethylamino)-9-(o-chloroanilino)xantylbenzoic acid lactam).

3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluorane, 3-diethylphumino-7-(o-chloraninunonfluorane, 3-dibdelamino-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)fluoran, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylosubiran, 6'-bromo-3'-methoxy-benzoindolino-pyrylosubiran, 3-(2'- Hydroxy-41-dimethylaminophenyl)-3-(2'-methoxy-5'-chlorophenyl)phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5 3-(2'-hydroxy-47-dimethylaminophenyl)-3-(2'-methoxy-51-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)fluoran, 3-pyrrolidino-7-(di-P-chlorophenyl)methylaminofluorane, 3-diethylamino-5-chloro-7-(α-)enylethylamino)fluoran, 3 -(N-ethyl-P-1~luidino)-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-(0-methoxycarbonylphenylamino)fluoran, 3-diethylamino-5-methyl-7- (α-phenylethylamino)fluorane, 3-diethylamino-7-piperidinofluorane, 2-
Chloro: 1-(N-methyl 1-luidino)-7-(p
-n-butylanilino)fluoran, 3-(N-benzyl-N-,cyclohexylamino)-
5,6-penzo 7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino 4
',5'-benzofluorane etc.

In the present invention, specific examples of particularly preferable rho-rco dyes to be included in the high temperature coloring layer include 1, 3-diethylamino-7-chlorofluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 3 -cyclohexylamino-6-chlorofluorane.

Examples include 3-diethylaminobenzo[α]fluoran.

In the present invention, in order to bind and support the leuco dye and color developer on the support, various commonly used binders can be used as appropriate, such as polyvinyl alcohol, starch and its derivatives, methoxycellulose, hydroxyl, etc. Cellulose derivatives such as ethyl cellulose, carboxymethyl cellulose, methyl cellulose, and ethyl cellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylic amide/acrylic ester copolymer, acryl amide/acrylic ester/methacrylic acid ternary copolymer, styrene/ Maleic anhydride copolymer alkali salt, isobutylene/maleic anhydride copolymer alkali salt,
In addition to water-soluble polymers such as polyacrylamide, sodium alginate, gelatin, and casein, polyvinyl acetate, polyurethane, styrene/butadiene copolymer, polyacrylic acid, polyacrylic ester, vinyl chloride/vinyl acetate copolymer, and Latexes such as butyl methacrylate, ethylene/vinyl acetate copolymer, and stycine/butadiene/acrylic copolymer can be used.

In addition, in the present invention, in addition to the leuco dye and color developer, if necessary, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers, surfactants, thermofusible substances ( or lubricant), etc. can be used in combination. In this case, fillers include, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, and surface-treated inorganic fine powders such as calcium and silica. , 41 kinds of fine powders such as urea-formalin resin, styrene/methacrylic acid copolymer, polystyrene resin, etc.
(Fusible substances include, for example, higher fatty acids or their esters, amides, or metal salts, as well as various waxes, condensates of aromatic carboxylic acids and amines, benzoic acid phenyl esters, higher linear glycols, Examples include dialkyl 1,4-epoxy-hexahydrophthalate, higher ketones, and other heat-fusible organic compounds having a melting point of about 50 to 200°C.

The two-color heat-sensitive recording material of the present invention can be modified in various ways. For example, in order to more completely prevent the influence of the decolorizing effect of the intermediate layer decoloring agent on the high-temperature coloring layer during high-temperature coloring, An intermediate layer, such as a fusible material layer, can be provided between the high temperature coloring layer and the color erasing agent intermediate layer.

(Effects) The two-color thermosensitive recording material of the present invention has the above-mentioned structure, and when coloring is performed at a high temperature, the decoloring agent contained in the intermediate layer acts on the coloring reaction system of the low-temperature coloring layer to produce a low-temperature coloring image. It erases the color, but does not affect the high temperature coloring layer. Therefore, the two-color image formed from the heat-sensitive recording material of the present invention has good color separation and provides a clear low-temperature color image and a high-temperature color image.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples. Note that the parts and percentages shown below are all based on weight h (group 7
(It is Q.

Example 1 Ta.

[Dispersion liquid -Δ]

3-(N-Ethyl-N-amylamino)-20 parts 6-methyl-7-anilite fluoran (black) 10% hydroxyethyl cellulose aqueous solution 20 Water 6
01! [Dispersion-B] 3.3'-Dichlorophenylthiourea 15 parts Calcium carbonate 511 Polyvinyl alcohol (10% aqueous solution) 20/1 Water
6Qlt [Dispersion-C] 3-Diedylamino-7-chloro 20 parts Fluorane
(Red) 10% hydroxyethyl cellulose aqueous solution 2011 Water 60 parts [Dispersion-D] Bisphenol A 15 parts Stearamide 1Qn 10% hydroxyethyl cellulose aqueous solution 5 Calcium carbonate 107/Water 7071 Dispersion A prepared as above 10 parts , dispersion 840
1 part and 30 parts of water were mixed and stirred to obtain a thermosensitive color forming liquid for low temperature use. On the other hand, 10 parts of dispersion liquid, 3 parts of dispersion liquid
0 parts and 20 parts of water were mixed and stirred to obtain a thermosensitive coloring liquid for high temperature coloring.

Furthermore, an intermediate layer forming liquid for forming an intermediate layer was prepared at the following ratio.

Distearylamine 25 parts lO% polyvinyl alcohol aqueous solution 10//Water 50
Each of the solutions prepared above was placed on commercially available high-quality paper with a basis weight of about 50 g/rrr, and the high temperature heat-sensitive color forming solution (dry weight, 5.5 g/nf), intermediate layer forming solution (dry weight, 5.5 g/nf), Time coating amount 2
．． 5g/rl) and a low-temperature heat-sensitive coloring forming liquid (dry coating amount: 0g/rl) were applied and dried to obtain a two-color thermosensitive recording material '1' of the present invention.

Example 2 The two colors of the present invention were prepared in the same manner as in Example 1 except that 3,3'-dichlorophenylthiourea in the dispersion of Example 1 was replaced with 3,3'-difluorophenylthiourea. A thermosensitive recording material was obtained.

Comparative Example 1 A comparative two-color heat-sensitive recording material was obtained in the same manner as in Example 1 and 1.1 except that 3,3'-dichlorophenylthiourea in the dispersion solution in Example 1 was replaced with bisphenol A.

Comparative Example 2 Example 1 except that distearylamine in the intermediate layer forming liquid of Example was replaced with tetraethylammonium chloride.
A comparative two-color heat-sensitive recording material was obtained in the same manner as described above.

The two-color thermal recording paper obtained as described above was measured using a thermal inclinometer with a built-in thermal head (Toyo Seiki Co., Ltd. 1ll) at a head temperature of 70 to 150°C, a crimping time of 1 second, and a crimping pressure of 2 kg.
/cJ to test the color tone, color separation, etc. of low-temperature and high-temperature colored images. As a result of the test, in the samples of Comparative Examples 1 and 2, the low-temperature colored image did not disappear during high-temperature coloring, and the developed color tone was mixed and the image was unclear. On the other hand, in the sample of Example 1.2, the low-temperature colored image disappeared during high-temperature coloring, resulting in a clear two-color image with good color separation.

Patent applicant Rico Co., Ltd. Representative Patent Attorney Toshiaki Ikeura

Claims (1)

[Claims] (1) 3WJ of a high-temperature color forming layer, an intermediate layer containing a decoloring agent, and a low-temperature color forming layer are laminated in this order on the support, and the iF6 color layer contains a leuco dye and a phenolic compound. The intermediate layer contains a heat-fusible aliphatic amine as a decolorizing agent, and the low-temperature coloring layer contains a leuco dye and the following general formula (A
) A two-color heat-sensitive recording material comprising a thiourea derivative represented by: General formula (Δ): (In the formula, It l and It z are hydrogen, halogen, trifluoromethyl group, or an alkyl group having 1 to 4 carbon atoms)