JPS6271692A - Color-forming recording material - Google Patents

Abstract

PURPOSE:To improve spontaneous color-forming property, solubility and light resistance pressure-sensitive copying paper and thermal recording paper by having special benzofluoran compounds contained as a coloring agent. CONSTITUTION:Benzofluoran compounds shown in a general chemical formula (1) is used. In the formula, R<1> represents the alkyl group of carbon number 1-6, R<2> the alkyl group of carbon number 1-12 which may sometimes contain halogen atoms or an alkoxyl group as a substitution group, the alkenyl group of carbon number 3-12, the benzyl group or cycloalkyl group which may sometimes contain halogen or a lower alkyl group atoms as a substitution group, X halogen atoms or a lower alkyl group, and m 0, 1, 2 or 3. If m represents 2 or 3, X is allowed to be the same or different, Benzofluoran compounds of the general chemical formula (1) are almost colorless and extremely stable in an atmosphere. Besides they are free from sublimation and spontaneous color formation, and is well soluble into organic solvents. The also form a dark purple color quickly by the use of a developer, thus proving their excellence in light resistance and moisture proofness.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to recording materials such as pressure-sensitive copying paper, heat-sensitive recording paper, and electrically conductive heat-sensitive recording paper.

More specifically, in the general formula (I) c, R1 is an alkoxy group having 6 to 6 carbon atoms, and R2 is an alkyl group having 1 to 12 carbon atoms, which may have a halogen atom or an alkoxy group as a substituent, and 6 carbon atoms. -12 fulkenyl group, benzyl group or cycloalkyl group which may have a halogen atom or a lower 7fi/kyl group as a substituent, X represents a halogen atom or a lower alkyl group, m is 0.
1.2 or 3. Note that when m is 2 or 6, X may be the same or different. Hereinafter, the same symbols have the same meaning. This invention relates to a recording material using a benzofluorane compound represented by the following as a coloring agent.

The benzofluorane compound represented by the general formula (I) is a new compound that was first synthesized by the present inventors and is itself an almost colorless compound that is extremely stable in the atmosphere and does not sublimate. It has no natural color development property (capri), is resistant to organic solvents, and quickly develops a dark purple color with a color developer, and the color image is lightfast.

Excellent moisture resistance.

Therefore, it is an extremely valuable new compound that can be used as the main component of a color former for black color recording materials, the demand of which has been increasing rapidly in recent years. Recording materials include pressure-sensitive copying paper, thermal recording paper, electrically conductive thermal recording paper, thermal transfer thermal recording paper, ultrasonic V,
Recording paper, laser recording paper, temperature-indicating materials, stamp ink,
Examples include type ribbon and ballpoint ink tatami.

"Prior art" and "Problems to be solved by the present invention" The following compound (A), which has a structure similar to the general formula (I), has a reddish-purple color hue with 6 dust, and has a strong spontaneous coloring property and is highly soluble. It also has the disadvantage of poor performance.

In addition, the following lower hardware (E) described in JP-A No. 48-75628 has a red hue with low commercial value. # It had the disadvantage of poor resolution. The present invention was arrived at as a result of intensive studies aimed at improving these drawbacks.

``Means for solving the problems'' and ``action'', that is, the present invention surprisingly provides a good compound by introducing an aryl group into the amino group at the 10-position of the known compound (A) mentioned above.
), and was arrived at as a result of further research. The object of the present invention is to provide a color-developing recording material.

In order to clarify these excellent properties, the compounds (C), (D), (E), CF), “C
G), (H).

The results of a comparative test between (I) and known compound (A) are shown.

(C) 5-methoxy-10-(N-ethyl-N-p-tri/I/)aminobenzoCC) Fluorane (D) 5-butoxy-10-(N-ethyl-N-p-tolyl)aminobenzoCC) Fluorane (E) 5-hexyloxy-1
0-(N-ethyl-N-p-)su/I/)aminobenzo[C]fluoro(F)5-hexyloxy-10-(N-
Methyl-N-pheny/I/)aminobenzoCC)fluora(G)5-hexyloxy-10-(N-ethyl-N
-p-) ρ) Aminobenzo[C]fluoro(F-ri) 5-
Pentyloxy-10-(N-ethyl-N-1;)-)
Aminobenzo(C) 7 lvO(I) 5-octyloxy-10-(N-ethyl-N-p-)A/)Aminobenzo(C) 7 A/O Comparative test 1-Dilute acid water solution Degree of color development when dissolved in - Compound (A),
15 in 30ml of 1.5% toluene solution of (C) to (G)
Add a 10% acetic acid solution and shake vigorously for 1 minute. The absorbance at the maximum absorption wavelength of each compound was as shown in Table 1.

Table 1 JJeO As the novel benzofluorane compounds (e) to (G) have an aryl group, they showed extremely little color development in the dilute acid ice-melting solution compared to known similar benzofluorane compounds. This means that when using the compounds of the present invention to produce pressure-sensitive copying paper, the pH at the time of microencapsulation! 11 07
This shows that no color development occurs due to H2 acid.

Comparative Test 2 - Lightfastness of pressure-sensitive copying paper capsule surface - Compound (
A) Using (a> to (G)), upper sheets (a) to (f) of pressure-sensitive copying paper were manufactured according to the method described in Example 1 below.

The coating surface of the resulting upper paper was exposed to sunlight for 50 minutes and the degree of coloring was measured using a reflection densitometer (Macbeth M RD-514).
It was measured using a Lattenona 58 filter.

The results are shown in Table 2.

Table 2 The results show that the compound of the present invention is stable to light and has little coloration on the capsule surface.

From the above Comparative Tests 1 and 2, it was confirmed that the compound of the present invention is extremely excellent as a coloring agent for pressure-sensitive copying paper.

Comparative Test 3 - Degree of background color development (fogging) and background light resistance when made into thermal paper - Compounds (A) - (C) - (G) t - Thermal recording paper was prepared by the method of Example 3 described later. ) ~ (Yu) were manufactured.

The background color development (fogging) of these thermosensitive recording papers was measured using a reflection density needle and a 2-Tenna 58 filter. Furthermore, the surface of the heat-sensitive recording paper was exposed to sunlight for 2 hours and the degree of coloring was measured using a reflection densitometer in the same manner. (Filter Rattenner 58) The results are as shown in Table 3.

Table 3 As described above, it was confirmed that the heat-sensitive recording paper of the present invention has less background color development and superior background light resistance than those using known compounds.

Specific examples of benzofluorane compounds used in the present invention include the following. Both are almost colorless solids, which quickly develop a dark purple color when treated with silica gel.

5-methoxy-10-(N-methyl-N-pheniμ)aminobenzo(C)fluoran 5-methoxy-10-(N-methyl-N-p-tri)V
) Aminobenzo CC) Fluorane 5-benthyloxy(N-methyl-N-p-1-ly/
S/) aminobenzo CC) 7A/orane 5-methoxy-
1t)-(N-ethyl-N-phenyl)aminopene/[
C] Fluorane 5-: L80-butoxy-1o-(N-ethyl-N-
)22)V)Aminobenzo[C)Fluorane 5-hexyloxy-10-(N-ethytv-N-pheny/L/
) Aminobenzo CC) Fluorane 5-methoxy-10-
(N-ethyl-N-p-tolyl)aminopenz[C]fluorane 5-ethoxy-10-(N-ethyl-N-p-)su)V
)AminobenzoCC)Fluorane 5-1so-propo#cy10-(N-x4-tv-N-p-)lyl)AminobenzoCC)Fluorane 5i so-butoxy-10-(N-ethyl-N-p-tolyl )aminobenzo(C)fluorane 5-tert-p)oxy-10
-(N-x/L/-N-p-)lyl)aminobenzo(
0) Fluorane 5-sec-pentyloxy-10-(
N-ethyl-N-p-tolyl)aminobenzoCC,l fluorane 5-octyloxy-10-(N-ethyl-N
-p-triAI) aminobenzo CC) fluorane 5
-lauryloxy-10-(N-ethyl-N-p-tri/L/)aminobenzoCC)7/L/oran 5-cyclobentyloxy-10-(N-ethyl-N-p-)
lylu)aminobenzoCC)fluoran 5-p-methylbenzyloxy-10-(N-ethyl-N-p-)su/L
/) Aminobenzo CC) Fluorane 5-butoxy-10
-(N-propyl-N-p-)lyl)aminobenzo(0)fluorane 5-ethoxy-10-(N-:L
so-benthru N-pheny A/) aminobenzo (C)
Fluora, 5-methoxy-10-(N-hexyl-N
-p-tri/I/)aminobenzo[C]fluorane 5-
Hexyloxy-10-(N-ethyl-N-m-tolyl)aminobenzo[C]fluorane 5-hexyloxy-10-(N-methyl-N-p-chloropheni/L/)
aminobenzo CC) fluorane 5-ethoxy-10-(
N-methyl-N-〇-methyl-p-chloropheni/l/
)Aminobenzo-CC)Fluoran 5-hexyloxy-10-(N-ethyldiN-p-ethylphenyl)aminobenzoCC)Fluoran 5-ethoxypropoxy-10-(N-ethyl-N-p-)lyl)aminobenzoCC ) Fluorane 5-chlorobutoxy-
10-(N-ethyl-N-p-tolyl)aminobenzo [
C] Fluorane The benzofluorane compound used in the present invention can be synthesized by the following method.

That is, first, meta-aminophenol/L' visiting conductor (Otori) and phthalic anhydride (phthalic anhydride value) are reacted to form a 2-(4'-amino-2'-hydroxy)-benzoylbenzoic acid derivative (f
f).

(I) (厘)
(y) Next, this 2-
(4'-amino-2'-hydroxy-pensy/L')
Benzoic acid derivative (N) and 1, 4 represented by general formula (M)
- A pensifluorane compound represented by the general formula (I) can be synthesized by condensing the compound with a dihydroxynaphthalene conductor using a dehydrating agent such as sulfuric acid, polyphosphoric acid, zinc chloride, or acetic anhydride.

In addition, 1゜4- for the compound represented by the general formula
Using dihydroxynaphthalene O1), the following structural formula (
Vl) (7) 5-Hydroxy-10-substituted amino-benzo[C]fluorane was synthesized, followed by dialkyl sulfate,
The compound of general formula 0) can also be obtained by the action of an alkylating agent such as an alkyl halide.

These dyes may be used alone or in combination of two or more. Additionally, known coloring agents that develop various hues may be used in combination within a range that does not impair the performance of the compound of the present invention. Nine words are 3
．． 5-(bis-7minophenyl)-6-amino7thalide, 3.3-(bisindoly/L/)phthalide, 5-7
Minofluorane, 2,6-diamitfluorane, spiropyran, phenoxazine, phenothiazine, leucoolamine, lactobazozymethane, 6-indoli IL/-
It is used in combination with a coloring agent such as 3-aminobutene-phthalide and 3-indolyl-6-amidiphenyl azaphthalide.

When manufacturing pressure-sensitive copying paper, various bath agents such as 7 to kylbenzene-based, alkyl biphenyl-based, alkylnaphthalene-based, diarylethane-based, hydrogenated terphenyl-based, and chlorinated paraffin-based bath agents are used to remove coloring agents. They can be used alone or in combination, and a coacervation method, an interfacial polymerization method, etc. can be used for encapsulation.

Color developers include clays such as bentonite, activated clay, acid clay, naphthol, salicylic acid, salicylic esters, metal salts of salicylic acid, bisphenol A1 p-hydroxybenzoic acid ester/V-based hydroxy compounds, p
- Phenylphenol formalin m fat, p-octylphenol formalin resin, their Kinjo salts, etc. are used.

In the production of heat-sensitive recording paper, polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, carboxymethyl 7-rose, gum arabic, gelatin, casein, marten powder, polyvinylpyrrolidone, styrene-maleic anhydride, and the like are used as binders. (Hardware etc. can be used, and as a color developer 4-'t, ert
-butylphenol, 4-pheny/I/phenol, 4
-Hydroxydiphenyl ether, α-naphthol, β
-Melting points of naphthol, 4-hydroxybenzoic acid methyl ester, 4-hydroxybenzoic acid benzyl ester, bisphenol A, 4,4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-methyldiphenylsulfone, etc. from 80°C to 180°C It can be used on hydroxy compounds with

In addition, as a sensitivity improver, urea, anhydrous 7-I/acid, acetanilide, paraffin wax, carnauba wax, higher fatty acids, higher fatty acid esters, higher fatty acid amides, salicylic acid, phthalic acid esters, terephthalic acid esters, naphthol benzyl ether, 1° 4-thia ρ-coxinaphthalene, m-ter7 ale, p-benzylbiphenyl, dibenzylbenzene, 1-hydroxy-2-naphthoic acid ester, 2-hydroxy-3-77 acetic acid ester, 4.4
'-Dialkoxy l diphenyl sulfone, penzamide, diphenylamine, benzene sulfonamide, benzene sulfonanilide, force/L/ hazol, high) =
o JIE using quinone dibenzyl ether etc. is possible.

Next, the synthesis method will be specifically explained by giving a synthesis example.

Synthesis Example 1 5-methoxy-10-(N-ethyl-N-rootli/L
/) Aminobenzo CC) Synthesis of fluoran 98% sulfuric acid 5
0g/to 2-(2-1 tro#cy4-(N-ethyl-N
-p-)lyl)aminocobenzoylbenzoic acid 18.8N
and 1,4-dimethoxynaphthalene 94f #20~
Stir at 25°C for 24 hours and then. The reaction product was poured into ice water at 500 f, and the precipitated solid matter was crushed. The obtained cake was made alkaline by adding 500 ml of toluene and 701 20% sodium hydroxide water bath solution, and then stirred at 85° C. for 50 minutes. Next, the I-luene layer was separated, concentrated to dryness, and then recrystallized from butanol to obtain colorless 5-methoxy-10-(N
-ethyv-N-p-)jJlv)aminobenzo(C)ryorane (formula below) was obtained.

, yield 20.51 m, p, 242-245°C
(7)λ□ of this compound in methano-ρ/acetic acid (4:1)
, 421 n1 fl and 568 n Jn 647, activated clay, phenolic resin, bisphenol / L / A nib quickly develops a dark purple color.

The 1,4-dimethoxynaphthalene used here was synthesized by the method described in the Journal of the Japan Society for Organic Synthesis and Chemistry, Vol. 14, p. 515.

Synthesis Example 2 5-n-hexyloxy-10-(N-ethyl-N-p
-)S/I/)Synthesis of aminobenzo(C)fluorane 1.5-Hydroxy-10-(N-ethyl-N-p-
Synthesis of tri/I/)aminobenzo[C]fluorane 2-[2-hydroxy-4-(
18.8 F of N-ethyl-N-p-)su/L/)amine]benzoylbenzoic acid and 8.5 f/l of 1,4-dihydroxynaphthalene were dissolved and stirred at 20 to 25°C for 24 hours. The reaction mixture was poured into 50 ml of ice water, and the precipitated solid was evaporated. After neutralizing the obtained 90% with caustic soda, it was recrystallized from toluene by a conventional method to obtain colorless 5-
Hydroxy-1G-(N-ethyl-N-p-)lyl)aminobenzo[C]fluorane (formula below) was obtained.

Yield i 18.7f m, p, 280-282°C λmaX 432nm* in methanol-acetic acid (4:1)
I1.5-n-hexyloxy-10-(N-ethyl-
Synthesis of N-p-tolyl)aminobenzoCC)fluorane 5-hydroxy-10--(N-
Ethyl-Np-triρ)aminobenzo(e)fluoran 10f, potassium carbonate 3.511. N-hexyl promer f-4f was added and stirred at 80°C for 4 hours.

After the reaction, the reaction product was poured into water and extracted with 100 d of toluene. After concentrating the toluene layer to dryness, it was recrystallized from F) n-butano-y using a conventional method to obtain colorless 5-n-hexyloxy-1.
0-(N-ethyl-N-p-tolyl)aminobenzoC
C) Fluorane (formula % λmax of this compound in methanol/acetic acid (4:1)
are at 424nm and 569nln. It quickly develops a dark purple color due to activated clay, phenolic resin, and bisphenol/l/A.

Synthesis Examples 6 to 20 The benzofluorane compounds shown in the following table were synthesized in the same manner as in Synthesis Example 1 or 2. All of them are colorless compounds, and quickly develop a dark purple color due to activated clay, phenol resin, and bispheno-A.

Any known method may be used to produce pressure-sensitive copying paper using the benzofluorane compound thus obtained.

For example, US Pat. No. 2,800,458, US Pat.
The coacervation method described in No. 1, etc. can be adopted. In addition, for the production of heat-sensitive recording paper, for example,
A known method described in Japanese Patent No. 4039 may be employed.

The present invention will be explained below with reference to examples, but the present invention is not limited to the following examples.

"Example" Example 1 - Production example of pressure-sensitive copying paper - Compound 5-butoxy-10-(N-ethyl)v of Synthesis Example 5
-N-p-Tolyl)Aminobenzo[C]fluorane (7 parts) (same below) was dissolved in 96 parts of t-monoisoprobyl biphenylene Iv, and in this solution was added 24 parts of gelatin and 24 parts of gum arabic to 400 parts of water. The mixture was dissolved, the pH was adjusted to 7, a solution was added, and the mixture was emulsified using a homogenizer. After adding iooo parts of warm water to this emulsion and stirring at 50°C for 30 minutes,
Add about 1 part of % caustic soda aqueous solution and further heat at 50°C for 60°C.
The mixture was stirred for a minute.

Then, gradually add dilute acetic acid to adjust the pH to 4.5.
After stirring at 0℃ for about 1 hour, cool to 0-5℃ and further stir for 6 hours.
Stirred for 0 minutes.

Next, 35 parts of a 4% glutaraltehyde water bath solution was gradually added to harden the capsules, and then sterilized with a dilute caustic soda water solution.
The H was adjusted to 6 and the mixture was stirred at room temperature for several hours to complete encapsulation. No coloring phenomenon occurred during this operation.

This capsule liquid was evenly applied to paper with a wire bar and dried to obtain capsule coated paper (upper paper).9.

When this paper was superimposed on paper (lower paper) coated with phenol-formalin resin as a color developer and written with a ballpoint pen, deep dark purple letters immediately appeared on the lower paper. This image has excellent light and moisture resistance. In addition, the upper paper, Turnip 7-7, also showed excellent light resistance, and there was no coloration or decrease in coloring ability due to sunlight irradiation.

Example 2 - Production example of black coloring pressure-sensitive copying paper - 5-n-hexyloxy-10-one (blue coloring agent) as a coloring agent 1.
41 Spiro(chromeno(2,3-C) piracy/l/-4(H)-1'-phthalane J-7
-(N-Ethyl-N-pliers/L/)amino-ro-methyl-1-benzi/L/-3'-one (orange color former)
Capsule-coated paper (top paper) was prepared in the same manner as in Example 1 except that a mixture of 1.9 parts benzoyl leucomethylene blue (if color former) α8# and 95 parts of hydrogenated turpheny/v were used as the solvent. -Good friends. This paper was applied to Clay 1 as a color developer, superimposed on the hypodermic paper, and when written with a ballpoint pen, dark black letters appeared immediately. This image had excellent light and moisture fastness. In addition, the capsule surface of the top paper also exhibits excellent light resistance, and does not become colored or lose its coloring ability when exposed to sunlight.

Example 3 - Production example of thermal recording paper - 1 Preparation of color former dispersion (liquid A) 5-n-pentyloxy-10-(N-ethyl-N-p-)lyl)aminobenzo[C]fluorane (synthesis) Example 6) 5 parts kaolin 1511 U% polyvinyl alcohol dissolved in water 100 parts water
#85 The above mixture was pulverized using a paint shaker (■ Toyo Seiki Co., Ltd.) until the particle size of the coloring agent became 3 microns.

11 Preparation of developer and sensitizer dispersion (solution B) Bisphenol A 15 parts Zinc stearate io-stearamide 20 #10 Polyvinyl alcohol ~ Alcohol water i! 18 Liquid 150# The above mixture was ground in a paint shaker until the particle size was 6 square meters.

111 Preparation and Coating of 1 Heat-Sensitive Liquid 10 parts of liquid A and 65 parts of liquid B were mixed and stirred to obtain a heat-sensitive coating liquid. This blood was uniformly applied to the paper using a wire bar and then dried to obtain thermosensitive recording paper. This heat-sensitive recording paper had no background fog, quickly developed a dark purple color when heated with a thermal pen, etc., and the developed color image showed excellent solidity and moisture resistance. Furthermore, the coated surface also had excellent light resistance, and no coloring occurred due to sunlight irradiation.

Example 4 - Production of black coloring thermosensitive recording paper - 5-n-hexyloxy-10- (N~ethyl-N-p-tolylaminobenzo[C]fluoran (synthesis flJ2) as a coloring agent)
Part s 2-7 A thermosensitive recording paper was obtained in the same manner as in Example 6, except that a mixture of 2 parts of Nilino 6-N-ethyl-Nn-hexylaminofluorane (green color former) was used. This thermal recording paper is pure white with no background fog, and after being calendered, the thermal head printing device
When printed using Matsushita Electronic Components ■, a deep black image appeared immediately. Even if the pulse width is shortened and the color is developed at a low density, color shift does not occur and the skin remains intact. Also, obtained 72. The image and coated surface have excellent light resistance and moisture resistance.

"Effects of the Invention" The color-forming recording material of the present invention is such that the compound of general formula (I) added as a color former improves the color hue of the compound described in JP-A No. 47-4662 to a blackish color, iyt A friend that improves natural color development, solubility, and light fastness, pressure-sensitive copying paper,
It has high industrial value as thermal recording paper, etc.

Claims (1)

[Scope of Claims] [1] Color-forming recording material characterized by containing a benzofluorane compound represented by the following general formula (I) as a coloring agent ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) [In the formula, R^1 is an alkyl group having 1 to 6 carbon atoms, and R^2 is an alkyl group having 1 to 12 carbon atoms, which may have a halogen atom or an alkoxy group as a substituent, or an alkenyl group having 3 to 12 carbon atoms. A benzyl group or a cycloalkyl group that may have a halogen atom or a lower alkyl group as a group or substituent,
X represents a halogen atom or a lower alkyl group, m is 0, 1
, 2 or 3. Note that when m is 2 or 3, X may be the same or different. ]