JPS62121769A - Fluoran derivative, production thereof and recording material containing the same - Google Patents

Abstract

NEW MATERIAL:Fluoran derivatives of formula I (wherein R is CH3, C2H5). EXAMPLE:3-(N-methyl-N-cyclohexylamino)-6-methyl-7-anilinofluoran derivative of formula II. USE:Fluoran derivatives are heat-sensitive color forming components useful as a color forming component for thermal recording materials having excellent fastness to plasticizers, oils, org. solvents, etc. PREPARATION:2mol of a compd. of formula III is reacted with 1mol of a ketone of formula IV (wherein R is as defined above) in the presence of a condensing agent such as sulfuric acid, etc. and a catalyst such as FeCl3, etc. at 30-80 deg.C in the presence or absence of a polar solvent such as acetonitrile for 5-60hr. The reaction product is introduced into ice/water and neutralized. The resulting precipitate is recovered by filtration, dissolved in benzene, washed with an aq. soln. of 2% NaOH, concentrated and recrystallized from an org. solvent such as toluene, etc. to obtain a fluoran derivative in a high purity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to novel fluorane derivatives and methods for producing the same, and also to recording materials containing these derivatives as thermosensitive coloring components.

[Conventional technology]

Heat-sensitive recording materials using electron-donating fluoran dyes and electron-accepting compounds are generally widely known (for example, Japanese Patent Publications No. 51-23204 and No. 57-3159).
1.58-52356 and 60-36568). Examples of such fluoran dyes include:
As a black chromophore, 3-N,N-noethylamino7
'-〇-chloroanilinofluorane, 3-(N-methyl-N-cyclohexylamino)-6-methyl-7-anilite fluorane, and the like.

The minimum performance that such recording materials should have is: 1) sufficient color density and color development sensitivity, 2) no fogging, and 3) sufficient fastness of the color material after color development. , etc., but at present no one has been obtained that completely satisfies all of these performances.

[Problem that the invention seeks to solve]

In particular, the heat-sensitive recording paper using conventional fluoran dyes as described above has the disadvantage that the color disappears when a plasticizer, oil, organic solvent, etc. comes into contact with one colored portion.

The inventors of the present invention have made efforts to resolve the drawbacks of conventional fluoran dyes, and as a result, have developed a new compound obtained by condensation of a specific fluoran compound and a ketone as a heat-sensitive coloring component. The inventors have now completed the present invention based on the discovery that the fastness of the colored portion of the resulting recording material is significantly improved when the dye is used.

[Means for solving problems]

Therefore, according to the present invention, a fluoran derivative represented by the following general formula I is provided.

...l In the above formula, R represents a methyl group or an ethyl group.

The fluoran derivative according to the present invention is a plasticizer for various foods,
Since it has a relatively low solubility in oils, organic solvents, etc., it significantly improves the robustness of the colored portion of the heat-sensitive recording material. In addition, although these fluorane derivatives are almost white substances by themselves, they can be made into a good black tone by coming into close contact with an electron-accepting substance (color developer) such as bisphenol A or silica gel. It has color-forming properties and is extremely useful as a heat-sensitive color-forming component for heat-sensitive recording materials.

The fluoran derivative of general formula I is prepared by adding 2 moles of a compound represented by the following structural formula..., to 1 of a ketone represented by the following general formula (1), [in the above formula, R represents the same thing as defined above].
It can be produced by reacting with moles.

Specifically, for example, 2 moles of a fluoran compound having the structural formula... and 1 mole of a general ketone are mixed with sulfuric acid.

Using a condensing agent such as hydrochloric acid or phosphoric acid, in the presence of a catalyst such as ferric chloride, calcium chloride, boric acid, hydrogen sulfide and alkyl mercaptan, at a temperature of 30 to 80°C,
Allow time to react. Then, pour the reaction into ice water,
After neutralization, the precipitate was separated by furnace, dissolved in benzene, and washed with a 2% aqueous solution of caustic soda. The desired product can be obtained in high purity by concentrating the product and recrystallizing it from an organic solvent such as toluene, benzene, isopropyl alcohol, or acetone. Furthermore, if a polar solvent such as acetonitrile, tetrahydrofuran, or dioxane is used in one reaction, the desired product can be obtained in even higher yield.

A recording material can be prepared by a known method using the fluoran derivative of the general formula (2) as a heat-sensitive coloring component. For example, US Patent 2548366.2800457
A heat-sensitive recording material can be obtained by using the compound of general formula (1) as a color-forming component according to the method described in Japanese Patent No. 2,800,458.

〔Example〕

The present invention will be further explained below with reference to Examples.

[Synthesis Example 1] 3-(N-methyl-N-cyclohexylamino)-6-
Methyl-7-anirite fluorane 1. Q-.

Dissolve in 4 parts of acetone, 4 parts of acetonitrile, and 6 parts of concentrated hydrochloric acid, add 0.19 parts of ferric chloride, and heat at 60 to 65°C for 50 minutes.
Allow time to react.

After the reaction is completed, the reaction solution is poured into 30 mj of ice water, neutralized, and the precipitate is filtered. Next, this precipitate is dissolved in benzene and washed with an aqueous solution of sodium dihydroxide.

The benzene layer is separated, dried over anhydrous sodium sulfate, and concentrated. Subsequently, isopropyl alcohol was added to perform recrystallization to obtain white powder condensation products o and sy.

The melting point of this product was 237-239°C.

From the molecular weight measurement by permeation chromatography and the measurement by hydrogen and carbon-13 nuclear magnetic resonance apparatus, it was confirmed that it was a condensate of 2 moles of the raw material fluoran compound corresponding to the following structural formula (2).

Below, hydrogen, carbon-13, obtained by nuclear magnetic resonance, 1.52
(C(CH,)2)c''-NMR: δ(CDCl2.): 169.0
(C-9).

142.1 (C-6), 141.8 (C-3), 127
．． 2 (C-4).

115.0 (C-5), 41.7 (C-2), 31.4
(C-1).

31.1 (C-8), 18.3 (C-7) or less Gold n Note that this product exhibits a black color on silica gel, and the hue that develops when brought into contact with bisphenol A etc. is a black border color. Ta.

[Synthesis Example 2] 3-(N-methyl-N-cyclohexylamino)-6-
1 g of methyl-7-anirite fluorane was dissolved in 2 WL of methyl ethyl ketone, 4 g of acetonitrile, and 7 d of concentrated hydrochloric acid, and 0.11 l of ferric chloride was added.

React at 70-75°C for 10 hours.

After the reaction was completed, the same treatment as in Synthesis Example 1 was carried out to obtain 0.8619 of a white powder condensation product.

The melting point of this product was 215-219°C.

It was. yruno! From the molecular weight measurement using chromatography and measurement using a hydrogen and carbon-13 nuclear magnetic resonance apparatus, it was confirmed that this product was a condensate of 2 moles of the raw material fluoran compound corresponding to the following structural formula V.

The chemical shift values obtained by hydrogen and carbon-13 nuclear magnetic resonance are shown below.

H'-NMR: δ(CDC/,,): 5.13
(NH), 2.80 (NCR, ).

1.95 (ci, c(cn,)(cH2cH3)
), 1.45 (C(CH,XCH2CH,)).

0.66 (t, C(CM,)(C)I2C￥3)
)C・13−Lδ(CDC2,): 169.6(C
-11), 141.9 (C-8).

141.5 (C-5), 128.1 (C-6), 115
．． 4 (C-7).

45.2 (C-2), 34.2 (C-3), 31.1 (
C-10).

27, DC-1), 18.0 (C-9), 9.3 (C-
4) Furthermore, this product exhibits a black color on silica gel, and the hue that develops when brought into contact with bisphenol A etc. is as follows.
It had a black border color.

[Example 1] Dispersions A and B were prepared by pulverizing and dispersing the following components using an attritor.

[Dispersion A]

Condensation product obtained in Synthesis Example 1 20 parts by weight 10
% polyvinyl alcohol aqueous solution 20 1 water
60 N [Dispersion B] Bisphenol A 15 parts by weight Calcium carbonate 5110% Horibini polylicol aqueous solution 20 I Water
60 Next, liquid [A] and liquid [B] were mixed and stirred at a weight ratio of 1:5 to obtain a heat-sensitive coloring layer coating liquid.

This heat-sensitive coloring layer coating liquid was applied to the surface of commercially available high-quality paper using a wire parr, and dried to a coating weight of 51/rn.
After forming the thermosensitive coloring layer No. 3, a calendering process was performed to prepare a thermosensitive recording sheet.

[Example 2] A heat-sensitive recording sheet was prepared in the same manner as in Example 1, except that the condensation product synthesized in Synthesis Example 2 was used instead of the fluorane condensation product in Solution A.

[Comparative Example 1] Person in Example 1? 1! Instead of the fluoran condensation product of 3-(N-methyl-N-
A thermosensitive recording sheet was prepared in the same manner except that cyclohexylamino)-6-methyl 7-anilite fluorane was used.

The three types of recording materials obtained in the Examples and Comparative Examples shown above were tested in a thermal gradient tester at a temperature of 150°C and
A pressure of 'Q/cs2 was applied for 0.5 seconds.

The surface of the colored sample was covered with a plasticizer-containing soft PVC film for food packaging, and a load of 2501/cm2 was applied in an environment of 3°C, and the colored image was decolored after 24 hours. was visually evaluated. In addition, cottonseed oil was applied to the surface of the colored sample, and after it was left at 30° C. for 24 hours, the decolorization of the colored image was visually evaluated.

The results are shown in the table below.

Table 1 The criteria for evaluating concave plasticizer resistance and oil resistance were as follows.

○: There is no practical problem in decoloring the colored part.

X: Most of the coloring part was discolored, causing a practical problem.

〔Effect of the invention〕

By using the fluoran derivative according to the present invention as a thermosensitive coloring component, it is possible to easily obtain a thermosensitive recording material in which the coloring portion has excellent fastness to plasticizers, oils, organic solvents, and the like.

Claims (1)

[Claims] 1. A fluoran derivative represented by the following general formula I. ▲There are mathematical formulas, chemical formulas, tables, etc.▼... I In the above formula, R represents a methyl group or an ethyl group. 2. The following general formula I, ▲There are mathematical formulas, chemical formulas, tables, etc.▼... I [In the above formula, R represents a methyl group or an ethyl group] When producing a fluoran derivative, the following structural formula is used.
II, ▲There are mathematical formulas, chemical formulas, tables, etc.▼...II 2 moles of the compound shown by is the same as defined above]. 3. The following general formula I, ▲There are mathematical formulas, chemical formulas, tables, etc.▼... I [In the above formula, R represents a methyl group or an ethyl group] At least one fluoran derivative represented by the above formula is used as a heat-sensitive coloring component. A recording material characterized by containing.