JPH0911616A - Recording material - Google Patents

Abstract

PURPOSE: To provide a color recording material utilizing the color forming reaction of a leuco dye and a coupler, excellent in background whiteness and the preservability thereof and having high color forming sensitivity. CONSTITUTION: A toluene or xylene adduct of 2-anilino-3-methyl-6-(N-isobutyl-N- ethylamino) fluorane is added as a leuco dye.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color forming recording material utilizing a color forming reaction by contact between a leuco dye and a color developer.

[0002]

2. Description of the Related Art Technical Background A chromogenic recording material utilizing color development by a reaction between a leuco dye and a color developer is used as an output recording medium such as a facsimile or a printer, or a thermal recording paper used for a label or the like.
It is also widely used as pressure-sensitive copying paper. Various fluoran compounds are known as leuco dyes used for these recording materials, but color development sensitivity, whiteness of the background,
There is nothing satisfying all of the storage stability of the colored image and the background, and improvements thereof are desired. Similar technology JP-A-59-197463 2-anilino-3-methyl-6- (N-isobutyl-N
-Ethylamino) fluorane (abbreviated as Compound A)
Is known as one of black leuco dyes for color forming recording materials.

[0003]

The recording material containing the compound A as a leuco dye is not yet sufficient in terms of the whiteness of the background and the storability, and the present inventors have made various studies on its improvement. As a result, they have found that the use of an adduct of compound A with toluene or xylene as a leuco dye improves the above-mentioned drawbacks, and completed the present invention. That is, an object of the present invention is to provide a color forming recording material which is excellent in the whiteness of the background and the color development sensitivity, and is excellent in the preservability of the background and the color image.

[0004]

The present invention relates to a recording material utilizing a coloring reaction by contact between a leuco dye and a color developer, wherein a toluene or xylene adduct of compound A (compound A adduct and compound A as leuco dye) is used. Abbreviated).

The compound A adduct in the present invention is a compound obtained by adding 1 mol of toluene or xylene to 1 mol of the compound A, or a compound obtained by adding 1 mol of toluene or xylene to 2 mol of the compound A. The compound A adduct can be obtained by precipitating crystals from a toluene or xylene solution. Depending on the drying conditions of the compound A adduct precipitated from the toluene or xylene solution,
A 1: 1 adduct, a 2: 1 adduct, or a mixture thereof is obtained.

For example, at a temperature of 50 ° C. or lower, 20 to 50
A 1: 1 adduct is obtained by drying under a reduced pressure of mmHg for about 2 hours. A 2: 1 adduct can be obtained by drying by a method such as increasing the drying temperature or prolonging the drying time. In the production of the compound A adduct, the compound A
May be recrystallized with toluene or xylene, but industrially, in the usual reaction method represented by the following reaction formula, the final reaction is carried out in the presence of a toluene or xylene solvent to directly add the compound A. A method of manufacturing the body is preferred.

Embedded image That is, as shown in the above reaction formula, the addition reaction of the benzoic acid derivative and the diphenylamine derivative is performed in a condensing agent such as concentrated sulfuric acid to neutralize the reaction solution, and then a mixed solution of toluene or xylene and an alkaline aqueous solution. The inside is heated to carry out the ring closure reaction. The obtained toluene or xylene solution is concentrated to precipitate a product, and the crystal is dried under a drying condition suitable for the purpose to obtain a compound A adduct.

The color-forming recording material of the present invention can be produced according to a usual method using the compound A adduct as a leuco dye. That is, in the case of heat-sensitive recording paper, a coating solution which is an aqueous dispersion of a dye, a color developer and a binder may be applied and dried on a support such as paper and plastic film. In the case of pressure-sensitive copying paper, a leuco dye microencapsulated by a conventional method is dispersed with an appropriate dispersant and coated on a support such as paper to prepare a color former sheet.
A developer sheet is prepared by applying a dispersion liquid of a developer onto a support such as paper. The pressure-sensitive copying paper is manufactured by combining the two sheets thus manufactured. The pressure-sensitive copying paper may be a unit composed of an upper paper coated with a microcapsule containing an organic solvent solution of a leuco dye on the lower surface and a lower paper coated with a developer on the upper surface, or a microcapsule and a developer. And may be applied to the same paper surface.

As leuco dyes, 2-anilino-3-methyl-6- (N-i-amyl-N-ethyl) aminofluorane and 2-anilino are used in addition to the compound A adduct of the present invention used alone. Generally used as a leuco dye for heat-sensitive or pressure-sensitive recording materials such as 3-methyl-6-diethylaminofluorane and 2-anilino-3-methyl-6- (N-propyl-N-methyl) aminofluorane. You may mix and use what has been said. The mixing ratio of the dye and the color developer can be appropriately changed, but in general, the dye 1 is used.
1 to 10 parts by weight, preferably 2 parts by weight of developer.
-5 parts by weight. A sensitizer may be appropriately added to the coating solution depending on the purpose. Further, various auxiliaries such as a filler, a dispersant, an antioxidant, a desensitizer, an anti-tacking agent, an antifoaming agent, a stabilizer and an optical brightener may be appropriately contained.
Further, an overcoat layer may be provided on the recording layer or an undercoat layer may be provided between the support and the recording layer by a conventional method. As the developer, any of the acidic substances that can be used as the developer in the color forming recording material can be used, and similarly, the sensitizer, other auxiliary agents and binders can also be used in the ordinary color forming recording material. Any material that can be used can be used.

Examples of the color developer include acid clay, inorganic acid substances such as bentonite, bisphenol A, 4,
4'-sec-butylidene bisphenol, 4,4'-cyclohexylidene bisphenol, 2,2- (4-hydroxyphenyl) -4-methylpentane, 1,3-bis [1- (4-hydroxyphenyl)- Bisphenols such as 1-methylethyl] benzene, 1,4-bis [1- (4-hydroxyphenyl) -1-methylethyl] benzene, 2,2′-dihydroxydiphenyl and pentamethylene-bis (4-hydroxybenzoate) Compound,
1,7-di (4-hydroxyphenylthio) -3,5-
Sulfur-containing bisphenol compounds such as dioxaheptane, 4
-Benzyl hydroxybenzoate, ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, isopropyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, isobutyl 4-hydroxybenzoate, chlorobenzyl 4-hydroxybenzoate, 4 -Methylbenzyl hydroxybenzoate, 4-hydroxybenzoic acid esters such as 4-hydroxybenzoic acid diphenylmethyl, metal benzoates such as zinc benzoate and zinc 4-nitrobenzoate,
4-hydroxy-4'-methyldiphenyl sulfone, 4
-Hydroxy-4'-isopropoxydiphenyl sulfone, 4-hydroxy-4'-butoxydiphenyl sulfone and other hydroxy sulfones, 4-hydroxyphthalate dimethyl, 4-hydroxyphthalate dicyclohexyl,
4-hydroxyphthalic acid diesters such as diphenyl 4-hydroxyphthalate, hydroxynaphthoic acid esters such as 2-hydroxy-6-carboxynaphthalene,
Hydroxyacetophenone, p-phenylphenol,
Examples thereof include benzyl 4-hydroxyphenylacetate, p-benzylphenol, hydroquinone-monobenzyl ether, and novolac resins.

As the sensitizer, for example, higher fatty acid amide, benzamide, stearic acid anilide, acetoacetic acid anilide, thioacetanilide, dibenzyl oxalate,
Dimethyl phthalate, dibenzyl terephthalate, dibenzyl isophthalate, bis (tert-butylphenol),
Diethers of 4,4'-dihydroxydiphenyl sulfone, 1,2-bis (phenoxy) ethane, 1,2-bis (4-methylphenoxy) ethane, 1,2-bis (3
-Methylphenoxy) ethane, 2-naphtholbenzyl ether, diphenylamine, carbazole, 2,3-
Di-m-tolylbutane, 4-benzylbiphenyl, 4,
4'-dimethylbiphenyl, m-terphenyl, di-β
-Naphthyl phenylenediamine etc. can be mentioned.

Examples of the binder include starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, diisobutylene / maleic anhydride copolymer. Polymer salt, styrene / maleic anhydride copolymer salt, ethylene / acrylic acid copolymer salt, styrene / allylic acid copolymer salt, styrene / butadiene copolymer emulsion, urea resin,
Examples thereof include melamine resin and amide resin. Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 20 g of o- (4-N-isobutyl-N-ethylamino-2-hydroxybenzoyl) benzoic acid and 4-methoxy-
2-Methyldiphenylamine 14.2 g and concentrated sulfuric acid 9
It was added to 6.5 g and stirred at 10 to 15 ° C. for 20 hours.
The obtained reaction liquid was used as a 16.6% caustic soda aqueous solution 48.
1.3 g was added to neutralize, 100 ml of toluene was added, and the mixture was heated and stirred, and then the aqueous layer was separated. 82 g of 10% aqueous sodium hydroxide solution and 50 ml of toluene were added to the toluene layer, and the mixture was heated under reflux for 1 hour.
It was washed 3 times with water. The toluene layer was concentrated, and the precipitated crystals were dried under reduced pressure at 60 ° C. and 40 mmHg for 20 hours.
Toluene adduct of anilino-3-methyl-6- (N-isobutyl-N-ethylamino) fluorane (melting point 98.
2-11 g) was obtained. This crystal is N
It was confirmed by MR and HPLC analysis that the main component was a 2: 1 adduct (toluene content: 8.5% by weight).

Embodiment 2 FIG. In Example 1, xylene was used instead of toluene, and otherwise the same as in Example 1 to obtain a xylene adduct of compound A (having 1: 1 as a main component) (melting points 94.8 to 110. 8 ° C).

Embodiment 3 FIG. A toluene adduct of compound A (having 1: 1 as a main component) was obtained in the same manner as in Example 1 except that the drying conditions were 60 ° C., 40 mmHg, and 2 hours (melting points 95.6 to 114. 1 ° C., toluene content 14.0%).

Example 4 Compound A toluene adduct 2.19 prepared in Example 1
25.0 g of alkyldiphenylmethane (“Hisol SAS296” manufactured by Nisseki Chemical Co., Ltd.) and diisopropylnaphthalene (“KMC-11” of Kureha Chemical Co., Ltd.)
3 ") was mixed with 18.0 g and heated to dissolve (solution A). On the other hand, 10% of sulfonic acid-modified polyvinyl alcohol (Nippon Gosei Kagaku Kogyo Co., Ltd., “Gothenol CSK-50”)
Aqueous solution 15.0 g, 10% aqueous solution of ethylene-maleic anhydride copolymer (Monsanto "EMA-31") 7.
5 g, 2.5 g of urea and 0.25 g of resorcin were added and dissolved, and the pH was adjusted using a 20% aqueous sodium hydroxide solution.
It was adjusted to 3.4 (solution B). Solution A was added to solution B to form an emulsion using a homomixer, then 7.0 g of a 35% formalin aqueous solution was added, and stirring was continued at 50 to 60 ° C. for 1 hour. After cooling to 40 ° C., 28% ammonia water was added to adjust the pH to 7.5 to obtain a microcapsule dispersion liquid. 27.0 g of this dispersion, 3.5 g of wheat starch, 8%
A coating solution was prepared by mixing 8.5 g of a wheat starch aqueous solution and 34.0 ml of water. This coating solution was applied to white paper using a wire bar No. 12 and dried to prepare a color former sheet (upper paper) for pressure-sensitive copying paper.

Comparative Example 1 Instead of the compound A toluene adduct used in Example 4,
Using 2.0 g of Compound A, an upper paper was prepared in the same manner as in Example 4.

Test Example 1 As a storage stability test of the top paper prepared in Example 4 and Comparative Example 1, a heat resistance test (left at 110 ° C. for 10 hours) and a light resistance test (irradiation with a fade meter for 2 hours) were performed. The coloring degree was measured with a Macbeth reflection densitometer RD-514.
Table 1 shows the results. On the other hand, the coating surface of the resin lower paper was overlaid with the coating surface of the upper paper prepared in Example 4 and Comparative Example 1, and printing was performed with a typewriter to develop color. As a result, both were clearly printed in black. The lightfastness of the colored image was almost the same. Table 1 Before test Heat resistance test Light resistance test Example 2 0.09 0.10 0.11 Comparative example 1 0.11 0.15 0.14 (filter used: Ratten # 106)

[0018]

The color-forming recording material of the present invention has a high degree of whiteness on the background, excellent storage stability, and excellent color-developing sensitivity. It is also advantageous in terms of industrial production of the leuco dye used.

Claims (1)

[Claims] 1. A recording material utilizing a color reaction by contact between a leuco dye and a color developer, wherein the leuco dye is 2
-Anilino-3-methyl-6- (N-isobutyl-N-
A color-forming recording material containing a toluene or xylene adduct of ethylamino) fluorane.