JPH03179059A - Polymorph of 2-anilino-3-methyl-6-n-ethyl-n-tetrahydrofurfurylaminofluoran - Google Patents

Abstract

PURPOSE:To obtain a highly light-resistant polymorph of the title compd. by selecting a polymorph of the title compd. having a specific character. CONSTITUTION:A polymorph of the title compd. characterized in that the X-ray diffraction diagram by X-ray diffractometry with a Cu-Kalpha ray shows intense peaks at diffraction angles (2THETA) of 7.5 deg., 12.9 deg., 19.0 deg., and 22.5 deg. is selected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides 2-anilino-3-methyl-6-N-ethyl-
This invention relates to crystal modification of N-tetrahydrofurfurylaminofluorane. More specifically, the diffraction angle (2e) in the X-ray diffraction method using alpha rays for Cu- is 7.5@, 12
．． 2-anilino- characterized by an X-ray diffraction diagram showing strong peaks at 9″, 19.0@, and 22.5′″
This invention relates to a crystal modification of 3-methyl-6-N-ethyl-N-tetrahydrofurfurylaminofluorane.

Fluoran compounds have conventionally been used as coloring agents for thermal recording paper, electrically conductive thermal recording paper, pressure-sensitive copying paper, and the like.

Among them, thermal recording paper is a recording paper that does not generate noise or odor, and its uses have been rapidly expanding in recent years because it is easy to operate, requires no maintenance, and can perform high-speed recording. The main uses are factor ξ, P OS
(Point of Sales) labels, recording paper for analytical equipment, tickets for automatic ticket vending machines, and video printers that require gradation.

The fluoran compound used in such thermal recording paper needs to be excellent in color development sensitivity, color development density, light resistance of images and backgrounds, and storage stability. The 2-anilino-3-methyl-6-N-ethyl-N-tetrahydrofurfurylaminofluorane of the present invention is disclosed in JP-A-60-208
This is a fluoran compound described as a coloring agent in Japanese Patent No. 360, and satisfies the above requirements. As a result of further investigation of this compound, it was found that this compound has 2
It was discovered that there are different types of crystal transformations. Moreover, the two newly discovered crystal modifications were significantly different in light resistance, particularly in their performance against strong light such as sunlight. That is,
One is the X-ray diffraction method using alpha rays for Cu-Niokel diffraction angle (
2e) is 7.5', 12.9'19.0°, 22.5°
It is a crystal that shows a strong peak in (α-type modification), and the other is
Diffraction angle (2e) in X-ray diffraction method using α rays on Cu-
The crystal shows strong peaks at 6.5° and 24.5° (β-type modification). The α-type modification had much better light resistance than the β-type modification.

The fluoran compound of the present invention is produced by the following method.

1 mole of 2-(4-N-ethyl-N-tetrahydrofurfurylamino-2-hydroxy-benzoyl)-benzoic acid and 1 mole of 2-methyl-4-methoxy-diphenylamine in the presence of 80-100% sulfuric acid. , o −s o'
React for several hours at a temperature of c.

After the reaction, the reaction mixture is added to water and the precipitate is collected by filtration. Toluene and a 5-10% aqueous sodium hydroxide solution are added to the collected cake, and the mixture is stirred under reflux for 1-3 hours. After standing still, the toluene layer was separated, washed with water, concentrated, and
The crystals precipitated at 2-45°C are collected. 2-anilino-3 is slightly colored by drying this crystal.
-Methyl-6-N-ethyl-N-tetrahydrofurfurylaminofluorane (α modification) is obtained.

Next, the present invention will be specifically explained with reference to Examples and Comparative Examples.

Example (Production of α-type modification) 2-(
16.6 g of 4-N-ethyl-N-tetrahydrofurfuryl-benzoic acid (2-hydroxy-benzoyl)-benzoic acid
After completely dissolving, add 11.5 g of 2-methyl-4-methoxy-diphenylamine and heat to 5-10"C.
The reaction was carried out for 10 hours. The reaction mixture was added to 10,100 O of ice water, and the precipitate was filtered off. 450n of toluene in the cake
+j! and 340 g of a 10% aqueous sodium hydroxide solution were added thereto, and the mixture was stirred under reflux for 2 hours. After standing still, the toluene layer was separated, washed with water, and filtered and purified by adding 4 g of activated carbon. This toluene solution was concentrated, and crystals precipitated at a temperature of 42 to 45°C were collected. 2-anilino-3-methyl-6-N-ethyl-N-tetrahydrofurfurylaminofluorane 20 is slightly colored by drying the crystals.
．． 3 g was obtained. (n+, p.

162, 8-163.8°C) This is an α-type metamorphosis,
The powder X-ray diffraction pattern is shown in FIG.

Reference Example (Production of β-type Modification) A toluene solution that was reacted and purified with activated carbon in the same manner as in the example was concentrated, and crystals precipitated at a temperature of 10 to 20°C were collected. By drying these crystals, they are slightly colored2.
-anilino-3-methyl-6-N-ethyl-N-tetrahydrofurfurylaminol) L/ola 720.5 g was obtained. (m, p, 170.5-1 73.0°C) This is a β-type modification, and the powder X-ray diffraction pattern is shown in FIG.

Comparative Test Mixtures having the following compositions were separately ground using a dyno mill to prepare liquids A and B.

A liquid composition 1, 2-anilino-3-methyl-6-N-ethyl-N-tetrahydrofurfuryriamofluorane (α-type modification or β-type modification) 4g2.10%
Polyvinyl alcohol aqueous solution 30g3.5% Sannopco 1401 (Sannopco product, nonionic surfactant) aqueous solution 2g4/water
4g B liquid composition■, bisphenol A 2, CaC0-3, zinc stearate 4, stearic acid 0g 3g 3g g 5.10% polyvinyl alcohol water? guest performance
30g 6.5% Sannopco 1407 aqueous solution
2g7, water 50g Liquids A and B were mixed at a weight ratio of 4:16 to obtain a coating liquid for heat-sensitive recording paper. This coating liquid was applied to the surface of high-quality paper using a wire bar so that the solid content after drying was 5 g/bo, placed in a blower dryer, and dried at room temperature. A thermosensitive recording paper was obtained.

The results of a comparative test of the background light resistance of thermal recording paper using α-type transformation and β-type transformation are shown.

*The background color density was measured using a Macbeth reflection densitometer RD-918.

4. Brief explanation of the figures Figures 1 and 2 show 2-anilino-3-methyl-6
FIG. 3 is a powder X-ray diffraction diagram of α-type modification and β-type modification of -N-ethyl-N-tetrahydrofurfurylaminofluorane. In the drawings, the horizontal axis represents the diffraction angle (20), and the vertical axis represents the diffraction intensity.

Hodogaya Chemical Industry Co., Ltd.

Claims (1)

[Claims] Diffraction angle (2Θ) in X-ray diffraction method using Cu-Kα rays
2-anilino-3-methyl-6-N-ethyl-N-tetrahydro, which is characterized by an X-ray diffraction diagram showing strong peaks at 7.5°, 12.9°, 19.0°, and 22.5°. Crystal modification of furfurylaminofluorane.