JPS62161585A - Color developing recording material containing fluorane compound - Google Patents

Abstract

PURPOSE:To obtain a superior color developing recording material, by a method wherein a specific fluorane compound is contained therein. CONSTITUTION:A color developing recording material contains a fluorane compound shown by a formula (I) as a chromogen. The fluorane compound in use itself is substantially a colorless substance, but tends to immediately develop to black or violet black when being in close contact with an electron accepting material such as acid clay, clay, phenol-formalin resin, bisphenol A, or p- hydroxybenzoic benzyl ester. Because having the above properties, the fluorane compound is used as a black developing chromogen in a color developing recording material such as a thermosensible recording paper or a pressure sensitive copying paper. The fluorane compound in use has a superior color developing properties, and in addition, produces the thermosensible paper which scarely has dirty surfaces even if being stored for a long term under the environment of high temperature and humidity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chromogenic recording material characterized by containing a fluoran compound represented by the formula (in the formula Rrs represents a methyl group or an ethyl group) as a chromogen.

The fluoran compound represented by formula (1) used in the present invention is itself a substantially colorless substance, but may also contain electron-accepting substances such as acid clay, clay, phenol-formalin resin, bisphenol A, and fluorine-accepting substances. It has the property of rapidly developing a black-purple to black color when it comes into close contact with benzyl hydroxybenzoic acid ester. Because of these properties, in the present invention, this fluoran compound is used as a black-forming chromogen in color-forming recording materials such as heat-sensitive recording paper or pressure-sensitive copying paper.

Currently, the two chromogens that produce black color in chromogenic recording materials are 5-diethylamino-6-methyl-7-phenylaminofluorane and 3-N-methylcyclohexylamino-6-methyl-7-phenylaminofluorane. Seed compounds are widely used. However, with the development of thermal facsimile machines, which are a major use of thermal recording paper, there has been an increasing demand for thermal recording paper with a faster coloring speed, and both of these two types of fluoran compounds fully meet this demand. It is no longer something that can be done.

The fluoran compound used in the present invention is a new substance that can meet these demands, and the mixture of the fluoran compound of formula (1) and the color developer bisphenol A is similar to the compound of formula (Nita) or the compound of formula (sha). lower temperature (90
It has the characteristic that the density of color development at temperatures between 100° C. and 100° C. is extremely deep. Furthermore, the fluoran compound used in the present invention is clearly superior to the compound represented by the formula disclosed in JP-A-54-30909 as having a better degree of color development at low temperatures than known fluoran compounds. It has a black coloring property. A comparison of these is shown in Table 1.

Table 1 A O,090,130,751,091,181,
201,24B O,090,130,711,07
1,171,201,2500,110,14α32α
851.111.141.21D O,110,15
0,310,831,081,131,20K O,
100,130,611,011,161,191,2
3 In Table 1, Compound A and Compound B represent the compounds used in the present invention, namely 3-N-n-7'-methylamino-6-methyl-phenylaminofluorane and 3-N-n-propylethylamino- 6-Methyl-7-phenylaminofluorane, compound C is a compound of formula (n), i.e. 3-diethylamino-6-methyl-7-phenylaminofluorane, compound R is a compound of formula (n)
Compound E is 3-N-methylcyclohexylamino-6-methyl-7-phenylaminofluorane, and compound E is Bumon's compound, 3-N-1s.
o --': methylethylamino-6-methyl-7-phenylaminofluoran. The values in the table are from Example 1
, which shows the color development density at each temperature of the thermal recording paper produced in Example 2 and Comparative Example 1, using a dry heat tester (manufactured by Kishino Kagaku Kiyoshi Co., Ltd.) for heating for color development. A Macbeth reflection densitometer was used to measure the color density. The higher the numerical value indicating the color density, the darker the color is.

In other words, Table 1 shows that the fluoran compound used in the present invention has a 90°
It has been shown to have excellent coloring properties at temperatures around 100° C., and this property is extremely desirable as a coloring agent for heat-sensitive recording paper used in high-speed facsimiles.

The fluoran compound used in the present invention not only has excellent coloring properties as described above, but also the thermosensitive recording paper produced using it can be stored for a long time in a high temperature and high humidity environment even immediately after production. It also has the great feature of leaving very little dirt on the scalp.

The fluoran compound represented by the formula (I) is formed by combining a 1 molar proportion of a benzoic acid derivative represented by the formula (in which R is the same as above) and a formula (in which R' represents hydrogen or a lower alkyl group). 4-hydroxy-(or 4-lower alkoxy)-2-methyldiphenylamine in concentrated sulfuric acid.

The benzoic acid derivative used here can be obtained by reacting 1 molar proportion of the m-aminophenol derivative represented by the formula (wherein R is the same as above) with approximately 1 molar proportion of phthalic anhydride. This reaction proceeds by heating both in a solvent such as toluene, perchlorene, or chlorocene. It is advantageous to use the reflux temperature of the solvent used as the heating temperature, which varies greatly depending on the type of solvent, the concentration of the reaction solution, etc., and is often carried out in the range of 90 to 140°C. The reaction time is largely controlled by the heating temperature and is approximately 4~
It takes 20 hours. At this time, use acidic substances (
A Lewis acid such as anhydrous, proportionate zinc) may be added as a catalyst.

Furthermore, the above m-aminophenol derivative can be obtained by reacting resorcinol with n-propylamine.
It is obtained by N-alkylating propylamine phenol using a suitable methylating or ethylating agent.

Examples of color-forming recording materials containing the fluoran compound of the present invention as a chromogen include pressure-sensitive copying paper, heat-sensitive recording paper, thermal copying paper, electrically conductive recording paper, electrophotographic toner, stamp ink, typewriter ribbon, etc. can be mentioned, but it is not limited to these only. For example, U.S. Pat. No. 2,548,366 and U.S. Pat.
It can be carried out according to the methods described in each specification of No. 58. For use in heat-sensitive recording materials such as heat-sensitive recording paper or heat-sensitive copying paper, Japanese Patent Publication No. 40-60645 and 43-
The methods described in 4160 and 45-14039 can be used. For use as a toner for electrophotography, for example, the method described in JP-A-52-56932 is used, and for use in electrically conductive recording paper, for example, the method described in JP-A-Sho.
The methods described in Japanese Patent Application Laid-Open No. 48-101937, Japanese Patent Application Publication No. 10193-1988, and Japanese Patent Publication No. 56-10193 can be used. Of course, in these usages, the fluoran compounds of the present invention can be used alone or in combination, or even in combination with other chromogens.

Production Example 1 (Production of benzoic acid derivative) m-N-n-propylmethylaminophenol 5.7
? 5.6F of Oyohi phthalic anhydride was added to 15ml of toluene, heated under reflux with stirring for 7 hours, cooled, diluted with 50ml of toluene, and shaken twice with 70ml of 10ml aqueous sodium hydroxide solution. The benzoic acid derivative produced was extracted as a salt into the aqueous layer. Add flaked caustic soda to the extract until no more sodium salts of benzoic acid derivatives precipitate, and after cooling, add F.
lffl and washed with 50% isopropyl alcohol. n) Dissolve the IJium salt in 150% water, neutralize it to pH 4-5 using 50% sulfuric acid, collect the precipitated crystals,
Washed with water and dried 0-(4-N-n-propylmethylamino-2-hydroxybenzoyl)benzoic acid 7.9
F (yield: 73.1 cm) was obtained as white crystals with a melting point of 149-151°C.

Also, instead of m-1l-n-propylmethylaminophenol, m-N-n-propylethylaminophenol 6
．． 22 and perform almost the same operation as above to obtain o-
(4-N-n-propylethylamino-2-hydroxybenzoyl)benzoic acid 7,4f (yield 65.2%)
was obtained as white crystals with a melting point of 151.8-153°C.

In addition, m-N-n- used as a raw material in this experiment
Propylmethylaminephenol and m-N-n-propylethylaminophenol are prepared by mixing resorcin and n-propylamine in the presence of anhydrous zinc chloride to give a
m-n-propylamine phenol obtained by heating to 0°C (boiling point 122-125°C 10.5-1+mmHg)
A substance f6') which is oily at room temperature and obtained by alkylating it using a methylating or ethylating agent using a conventional method.

Production Example 2 (Production of fluoran compound) The product was produced in Production Example 1. -(4-N-n-propylmethylamino-2-hydroxybenzoyl)benzoic acid 7.6 f and 4-ethoxy-2-methyldiphenylamine 6.12 were dissolved in concentrated sulfuric acid 4
After stirring was continued for 48 hours at a temperature of 20 to 25°C, the mixture was poured into ice water, and the precipitate was collected. The cake was dispersed in water, made alkaline by adding an aqueous solution of caustic soda, and filtered again. The P residue was washed with water and recrystallized with toluene to obtain 3-N-n-propylmethylamino-6-methyl-7.
-Phenylaminofluorane 98y (yield 84.5% from benzoic acid derivative) was obtained as fine brown crystals with a melting point of 175-178°C.

Also, o-(4-N-
10.3 t of 3-N-n-propylethylamino-6-methyl-7-phenylaminofluorane was prepared by much the same procedure as above using n-propylethylamino-2-hydroxybenzoyl)benzoic acid aor 86.4% yield from acid derivative) with melting point 172-17
Obtained as light pink fine crystals at 4°C.

Example 1 3-N-n-propylmethylamino-6-methyl-7-
Phenylaminofluorane 31.5F, clay (Engelno Ruto rtTW-90J) 15. Of.

15C aqueous solution of polyvinyl alcohol (Kuraray-105) 41.5F and pure water 40.11C were placed in a polyethylene bottle with a VC of 150ml together with glass beads (diameter 1-1.5+m) 15C1, and the bottle was sealed tightly. was attached to an Indian conditioner and shaken at a frequency of 630 vibrations/min for 6 hours. Remove glass beads to reduce particle size to 2~
A viscous aqueous suspension containing 3μ of 3-N-n-propylmethylamino-6-methyl-7-phenylaminofluorane particles was obtained.

On the other hand, hisphenol A10. ! IM', clay (Engelhard rUW-90J) 8. Of, polyvinyl alcohol (Kuraray-105) 15% aqueous solution 41.5
1 and pure water 40. Of glass beads (diameter 1-1.5
(2) It was placed in a 250-sized polyethylene bottle along with 150y and sealed, and attached to a Red Devi 1 India conditioner. After shaking at a vibration frequency of 630 times/min for 10 hours, the glass beads were removed to obtain an aqueous suspension containing bisphenol A particles with a particle size of 2 to 3 microns.

To this aqueous suspension of bisphenol A, the above 3-N-n
A water suspension of -propylmethylamino-6-methyl-7-phenylaminofluorane was added and stirred for 30 minutes to mix well. This mixed solution was applied to white base paper by hand using a wire rod No. 12, and dried with warm air at 60°C for 3 minutes to obtain very white thermal recording paper with almost no background dirt observed on the coated surface. Ta. This thermal recording paper developed a slightly reddish black color very quickly when heated with a hot needle, hot type, or hot pattern.

This thermal recording paper was tested at 70°C, 80°C, 90°C, 100°C, 1
Both sides were heated for 5 seconds at 10°C, 120°C, and 140°C to develop a color (slightly reddish black), and the color density of the colored side was measured using a Macbeth reflection densitometer RD-5i4 model (filter used). Latin+106). The results are listed in the Compound A column of Table 1.

Example 2 3-N-n-propylethylamino-6-methyl-7-phenyl was used in place of the 93-N-n-propylmethylamino-6-methyl-7-phenylaminofluorane used in Example 1. A thermosensitive recording paper was produced in the same manner as in Example 1 using aminofluorane. This thermosensitive recording paper was colored in the same manner as in Example 1, and the color density of the colored surface was measured, and the numerical values are shown in the Compound B column of Table 1.

Comparative Example Instead of 3-N-n-propylmethylamino-6-methyl-7-phenylaminofluorane used in Example 1, VC3-diethylamino-6-methyl-7-phenylaminofluorane, Ro-N-cyclohexyl Using methylamino-6-methyl-7-phenylaminofluorane and 3-N-1sO-A methylethylamino-6-methyl-7-phenylaminofluorane, heat-sensitive recording paper was prepared in the same manner as in Example 1. , the color was developed, and the color and density were measured. The measured values are shown in the columns for compounds C, D and E in Table 1, respectively. It should be noted that the coated surfaces of these heat-sensitive recording papers were slightly more stained than those obtained in Example 1.

Example 3 3-N-n-propylmethylamino-6-methyl-7-
Phenylaminofluorane 1. On the other hand, gelatin (isoelectric point aO) of 2.01 and carboxyl methyl cellulose of 0.52 were completely dissolved in 120 rnl of water (solution B). Next, liquid A and liquid B are mixed at 50 to 60°C, stirred at high speed to emulsify, and the pH is adjusted to a5 to 9. OK adjusted. After adjusting the pH, stir at high speed for 20 minutes and adjust the pH.
The mixture was gradually lowered to pH 3.8 with dilute acetic acid, cooled to 5-10°C with continued stirring, 6 ml of formalin (37%) solution added and stirring continued for an additional hour at 10-20°C.

Then pi (9) using sodium hydroxide solution (5)
, adjusted to 0. This emulsion was slowly stirred for several more hours to form extremely fine capsules [internally 1c3-N-n-propylmethylamino-6-
An emulsion containing an alkylnaphthalene solution of methyl-7-phenylaminofluorane was obtained.

This emulsion was applied to paper and dried to prepare a top sheet of pressure-sensitive copying paper. On the other hand, phenol phor? IJ resin was applied to paper and dried to create a lower paper.

When letters were written by placing the coated side of the upper sheet over the coated side of the lower sheet, black letters appeared extremely quickly on the coated side of the lower sheet.

Furthermore, when using paper coated with clay and dried instead of phenol-formalin resin, purple-black characters appeared.

Claims (1)

[Claims] A color-forming recording material characterized by containing a fluoran compound represented by the formula ▲ includes mathematical formulas, chemical formulas, tables, etc. ▼ (I) (in the formula, R represents a methyl group or an ethyl group) .