JPS63120760A - Fluorene compound and recording material obtained by using the same - Google Patents

Abstract

PURPOSE:To form a recording material such as pressure-sensitive copying paper, thermal recording paper, etc., which has excellent color forming sensitivity, color density, fastness of colored images, etc. and exhibits light absorption in the region of near-infrared rays, by using a specified fluorene compd. as an electron-donating color forming agent. CONSTITUTION:A fluorene compd. represented by formula I, wherein R1, R2, R3, R4, R5 and R6 are each a 1-4C alkyl or allyl; X is H, methyl or halogen, provided that when X is H, at least one of R1, R2, R3, R4, R5 and R6 is allyl.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel fluorene compound and its use in conventional techniques.Recording materials using electron-donating coloring agents include pressure-sensitive copying paper, heat-sensitive recording paper, and 4+ transfer recording paper. Various forms such as these are known.

Pressure-sensitive and heat-sensitive recording materials generally utilize a chemical reaction between an almost colorless electron-donating coloring agent and a coloring agent that causes the coloring agent to develop a special color upon contact and form a colored image. .

Compared to other recording materials such as electrophotographic and electrostatic recording materials, these recording materials are widely used in various fields because they can produce records in a short time using relatively simple equipment without the need for complicated processes such as development and fixing. It is used for. As electron-donating color formers used in such recording materials, triphenylmethane dyes, fluoran dyes, and the like are mainly used.

On the other hand, in optical character reading devices and label barcode reading devices, light sources with light wavelengths of 700 nm or more using light emitting diodes or semiconductor lasers have come to be commonly used.

However, the triphenylmethane-based dyes and fluorane-based dyes mentioned above are intended for reading using visible light and have almost no light absorption in the near-infrared region of 700 nm or more, so the above-mentioned reading devices cannot read their color. It's impossible.

Under these circumstances, the light absorption wavelength of the coloring body is 700 nm.
There is a strong demand for the development of the above electron-donating color former.

Conventionally, several proposals have been made regarding electron-donating color formers that absorb wavelengths in the near-infrared region.
There is a 7th grade. That is, Japanese Patent Publication No. 58-5940 proposes the use of divinyl group-containing phthalide derivatives. However, when this compound is used as a recording material, the image that develops when it comes into contact with a coloring agent absorbs light in the near-infrared region, but even before one color develops, it absorbs a considerable amount of light in the near-infrared region, so the color develops. When the image is read by an optical character reading device, it has the disadvantage that reading errors occur and the reading accuracy is poor.

Further, JP-A-59-199757 describes a fluorene compound represented by formula (n), and its colored image has absorption in the near-infrared region.

However, the colored image of formula (If) has the drawback of poor image stability, particularly light fastness, and also has the drawback of poor color development sensitivity when used on thermosensitive recording paper. Furthermore, when used in pressure-sensitive copying paper, the compound of Formula 1 (n) is difficult to dissolve in solvents such as alkylnaphthalene, making it difficult to form microcapsules with a high chain degree.

It has the disadvantage that it is difficult to obtain colored images with strong contrast.

Problems to be Solved by the Invention It is desirable to develop a color forming agent that is soluble in a solvent such as alkylnaphthalene, has excellent color development sensitivity, color density, fastness of color image, etc., and has absorption in the near-infrared region with reading accuracy. It is rare.

Means for Solving the Problems The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result they have arrived at the present invention. That is, the present invention relates to the general formula CI) (wherein R1, R2, R3, R4, R5 and R6 each represent an alkyl group or an allyl group having 1 to 4 carbon atoms, or hydrogen, methyl or halogen, provided that X is R1 for hydrogen
, R2, RS, at least one of R4, R5 and R6 represents an allyl group) and a recording material using the same.

The fluorene compound represented by the general formula (1) of the present invention is new, and it is a substantially colorless crystal and has no absorption in the near-infrared region, but it is compatible with acid clay, phenolic resins, phenolic compounds, etc. By contact with acidic substances,
The color changes from blue to green.

The present invention provides a recording material which has absorption in the near-infrared region around 700 nm to 1.000 nm and which has improved the above-mentioned drawbacks. In other words, the colored image produced by the compound represented by the general formula CI) has excellent light fastness, and when used in heat-sensitive recording paper, it is a highly sensitive recording material because the whiteness of the background is excellent, there is no misreading, and the color development speed is excellent. can be obtained. Furthermore, it is excellent in various fastness properties such as water resistance and heat and humidity resistance for single-color images.

In addition, when used as pressure-sensitive copying paper, the compound of general formula CI) is easily dissolved in solvents such as lunaphthalene in alcohol.
A colored image with strong contrast can be obtained.

Therefore, the fluorene compound represented by the general formula CI) has a wide range of uses as an electron-donating color former having absorption in the near-infrared region.

The fluorene compound represented by the general formula CI) of the present invention is produced, for example, as follows.

(1) General formula CI[[] In the C formula, R1, R2, R3, u4+R5, R6 and U
x represents the same meaning as above) in an inorganic acid, preferably in sulfuric acid.
Diazotization is carried out at 10°C, followed by stirring at 10°C to 130°C for several hours to several tens of hours to effect ring closure.

Furthermore, ring closure in the presence of copper powder or a copper compound is effective for improving the yield.

Next, the reaction product is neutralized with an alkali, and the precipitate is purified with a solvent by a known method to obtain a fluorene compound represented by the general formula CI) as substantially colorless crystals.

(2) A compound represented by the general formula (IV) (where Rt, u2rR51R4tRs +R6 and H °C preferably 80 °C to 150 °C
Stir with to close the ring. Note that ring closure in the presence of a carbonyl compound such as urea is effective in improving the yield.

Next, the reaction product is poured into water and the precipitate is purified with a solvent by a known method to obtain a fluorene compound represented by the general formula CI) as substantially colorless crystals.

The fluorene compound of the present invention, like conventional triphenylmethane dyes and fluorane dyes, can be used as an electron-donating coloring agent for recording materials such as pressure-sensitive copying paper, thermal recording paper, and thermal transfer recording paper. I can do it. It can also be used in combination with conventional triphenylmethane dyes and fluoran dyes.

In order to obtain pressure-sensitive copying paper using the fluorene compound of the present invention, first, microcapsules of a fluorene compound-dissolved oil are prepared. In this case, the microcapsules can be prepared by, for example, using a method as described in US Pat.
This can be done by incorporating diisopropylna-7talene or terphenyl oil in which -4% of a fluorene compound is dissolved. The particle size of microcapsules is usually around 5 μm. These microcapsules are supported on a support such as paper or plastic film using a binder, and layered with a coloring agent sheet having an electron-accepting compound layer as a coloring agent. By applying pressure to destroy the microcapsules and bringing the fluorene compound into contact with the coloring agent, a colored image can be obtained on the coloring agent sheet.

To obtain a heat-sensitive recording material using the fluorene compound of the present invention, the fluorene compound of formula 1 CI) and a coloring agent are separately mixed in a dispersion medium containing a binder so that the average particle size is 0.5 to 3μ. After dispersion, mix and add additives such as sensitizers and fillers as necessary to make paper.

It is created by coating on a support such as a resin film and drying it.

In the above, specific examples of the coloring agent are as follows.

P-octylphenol, P-tθr7-butylphenol, P-phenylphenol, 1,1-bis(p-
hydroxyphenyl)propane, 2,2-bis-CP-
hydroxyphenyl)-//lopane, 1,1-(bis-
(P-hydroxyphenyl)-cyclohexyl, 4.4
Phenolic compounds such as '-sulfonyldiphenol, bis-(3-7!J-4-hydroxyphenyl)sulfone, benzyl P-hydroxybenzoate, ether P-hydroxybenzoate.

Dibenzyl 4-hydroxyphthalate, dimethyl 4-hydroxyphthalate, ethyl 5-hydroxyinphthalate,
3,5-di-tart-butylsalicylic acid.

Examples of aromatic carboxylic acid derivatives such as 5.5-di-α-methylbenzylsalicylic acid and polyvalent metal salts thereof include carboxylic acids.

A specific example of the binder is methyl cellulose.

Methoxycellulose, hydroxyethylcellulose, carboxymethyl heptalulose, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch and its derivatives, casein, gelatin, styrene, alkaline salts of maleic anhydride copolymers , water-soluble ones such as alkaline salts of in(or diiso)butylene-maleic anhydride copolymer, polyvinyl acetate, vinyl chloride/vinyl acetate copolymer, polystyrene, polyacrylic acid ester, polyurethane, styrene/butadiene /A water-insoluble emulsion such as an acrylic acid copolymer is used.

Specific examples of sensitizers include waxes such as animal and vegetable waxes, polyethylene waxes, and synthetic waxes, higher fatty acids, higher fatty acid amides, higher fatty acid metal salts, and acetylated products of aromatic amines.

Those that are solid at room temperature and have a melting point of 80°C or higher, such as aromatic ether compounds and biphenyl derivatives, are preferred.

Further, a specific example of the filler is calcium carbonate.

Magnesium carbonate, magnesium oxide, silica, white carbon, Merck, clay, alumina.

Magnesium hydroxide, aluminum hydroxide, aluminum oxide, barium sulfate, polystyrene resin.

Examples include urea-formalin resin.

Other additives such as lubricants such as lead stearate, calcium stearate, and aluminum stearate, various surfactants, and antifoaming agents may be added as necessary.

The ratio of fluorene compound to coloring agent is usually 1:1 by dry weight.
It is used at a ratio of 1 to 1:10, and the application amount is 5% by dry weight.
~15? /-preferably 8-129 and /rt? It is. Further, if necessary, an intermediate layer may be provided between the heat-sensitive recording layer 1 and the support, or an overcoat layer may be provided on the heat-sensitive recording layer.

A one-color image can be obtained by heating the heat-sensitive recording material thus obtained with a thermal head or the like to bring the fluorene compound and the coloring agent into melt contact.

The fluorene compound of formula (1) of the present invention can also be used as a coloring agent for obtaining a thermal transfer type recording material.

To obtain a thermal transfer recording material using the fluorene compound of the present invention, a thermal transfer sheet is prepared by supporting the fluorene compound on a support, and a receptor sheet is prepared by supporting a coloring agent on the support. When a transfer sheet and a receiving sheet are placed one on top of the other and heated from the surface of the transfer sheet, a colored image is obtained on the receiving sheet.

The fluorene compound of the formula CI) of the present invention utilizes its excellent near-infrared light absorption property to produce color in recording materials for reading such as optical character reading devices and label barcode reading devices. It can be used as a drug.

Note that 1. When the fluorene compound of the present invention is used in a heat-sensitive recording label sheet, a heat-sensitive coloring layer containing the fluorene compound of the present invention and a coloring agent is provided on one side of the support, and is adhered to the other side of the support. It is sufficient to use a structure in which a peeler mount is provided through the agent layer.

Further, in this case, a protective layer may be provided on the one-color heat-sensitive layer in order to improve image stability, if necessary.

Example The present invention will be explained in more detail with reference to Examples below.

Example 1 3.6-bis(dimethylamino)fluorene spiro-(
9,3') -Production method of 5'-methyl-6'-dimethylaminophthalide s. Add 560 parts of s-his(baladimethylaminophel)-5-methyl-6-dimethylaminophthalide to the hardware, The reaction was carried out at 140-145°C for 20 hours.

Next, the reaction product was poured into 500 parts of ice water, and the precipitate was purified in toluene-methanol.

3.6-1:'S(dimethylamino)fluorene spiro-(9,3')-5'-methyl-6'-dimethylaminophthalide 4.01 was obtained.

mP, 23B-241°C.

Example 2 Method for producing 3-dimethylamino-6-diallylaminofluorene spiro-(9,3')-6'-dimethylaminophthalide. Ku\. 3-(2-amino-4-diallylaminophenyl)-5
5.0 parts of -(4-dimethylaminophenyl)-6-dimethylaminophthalide was dissolved in 60 parts of 80% sulfuric acid, and
Cool to ℃.

Next, add 0.86 parts of sodium nitrite to this at -5 to 5°C.
Add gradually while maintaining The diazotization was completed by stirring at the same temperature for 2 hours. This diazotized solution was mixed with 80% sulfuric acid.
0 part and 0.1 part of copper powder were gradually added to the solution kept at 35°C-40°C, and kept at 35°C-40°C for 1 hour after addition.
Heating to 0° C. for 3 hours completed ring closure. Then, the precipitate was neutralized in ice water and purified in toluene-methanol to give 3-dimethylamino-6-diallylaminofluorene spiro-(915')-6'-dimethylaminophthalide 3.91 from ζ. I got it.

mp, 203-205°C Examples 5 to 12 Fluorene compounds shown in Table 1 were synthesized according to Example 1 or 2, and their melting points were measured.

Example 13 Production of thermal recording paper Mixtures consisting of the following compositions were separately ground and dispersed using a sand grinder so that the average particle size was 1 to 3 μm to prepare liquids (A) to [C]. .

Next, [A] solution: [B] solution: [C] solution at 6:47:47
A heat-sensitive coloring layer forming solution was prepared by mixing in the proportions of
It was coated and dried on the surface of a high quality paper of 0y/G to give a dry solid content of 10p/FF/FF to obtain a heat-sensitive recording material (heat-sensitive recording paper) of the present invention.

Example 14 Production of thermal recording paper A thermal recording paper was used in the same manner as in Example 13, except that the fluorene compound synthesized in Example 2 was used in place of the fluorene compound of Example 1 used in Example 13.

Comparative Examples 1 to 3 Comparative thermal recording paper was prepared in the same manner as in Example 15, except that the leuco dyes shown in Comparative Examples 1 to 3 in Table 2 were used instead of the fluorene compound of Example 1 used in Example 13. I got it.

A color development test and a fastness test were carried out using the heat-sensitive recording paper of the present invention and a comparative heat-sensitive recording paper obtained as described above.

The results are shown in Table 2.

(1) Color development test 80°C using a Roseaster tester.

The recording paper was pressed for 5 seconds at 90°C and 140°C, and the density of one color was measured using a Macbeth densitometer RD-914.

(2) Fastness test The test was conducted using thermal paper that was colored at 140°C for 5 seconds.

Water Resistance 2 The color-developed thermal paper was immersed in 1 ton of water for 15 hours, and then the density was measured and calculated using the formula % (%). The higher the value, the better.

Moisture resistance: The concentration was measured after being left under saturated water vapor pressure at 60°C for 24 hours, and calculated using the formula % (%). The higher the value, the better.

Light resistance 2 The concentration was measured after irradiation at 10,000 lux for one week and calculated using the formula % (%). The higher the value, the better.

(3) Absorption wavelength region, background coloration absorption wavelength region: The reflection spectrum of the colored area was measured at 140° C. for 5 seconds.

Background coloring property: Degree of coloring ('coloring') immediately after preparing thermal recording paper (measured with a Macbeth densitometer RD-914) From the results in Table 2, 1. The fluorene compound of the present invention has an absorption wavelength range of around 700 to 1,000 nm. It is clear that it absorbs up to the near infrared region and has excellent color development sensitivity and fastness.

Example 15 Production of pressure-sensitive copying paper 3 parts of the fluorene compound obtained in Example 2 was dissolved in 98 parts of diisopropylnaphthalene at 50°C, and at this temperature a solution of 20 parts of gum arabic and 160 parts of water was added to emulsify. do. 20 parts of acid-treated gelatin and 160 parts of water are added to this, and the pH is adjusted to 5 with acetic acid. Next, 500 parts of water was added to allow coacervation to proceed, forming a thick gelatin-gum arabic liquid film around the diimpropylnaphthalene oil droplets, and adjusting the pH to 4.4, followed by 4 parts of a 57% formalin solution. is added to form a dura mater. Next, this system was cooled to 10°C, and a dilute aqueous sodium hydroxide solution was added to adjust the pH.
is set to 9 and allowed to stand for several hours to allow encapsulation to proceed. This encapsulation liquid has an average type of 14 op/rr? It is coated on paper so that the dry solid content is 51/d and dried to obtain an upper sheet. The resulting upper sheet was superimposed on a color developer sheet containing paraphenylphenol-formaldehyde polymer as a color developer, and when writing pressure or typewriter printing pressure was applied, a green color developed. This copy image is 700
It had absorption in the near-infrared region around ~1,000 nln, and had excellent water resistance and light resistance.

Effects of the Invention A fluorene compound with excellent color development sensitivity 1 color density and a color image with excellent near-infrared absorption characteristics was obtained. Moreover, this colored image has excellent water resistance and light fastness.

Claims (1)

[Claims] 1. General formula (I) ▲ Numerical formula, chemical formula, table, etc. ▼ (I) (In the formula, R_1, R_2, R_3, R_4, R_5 and R_6 each have 1 to 4 carbon atoms. an alkyl group or an allyl group, and X represents hydrogen, methyl, or halogen; however, when Fluorene compound. 2. General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1, R_2, R_3, R_4, R_5 and R_6 each represent an alkyl group or allyl group having 1 to 4 carbon atoms. , X represents hydrogen, methyl or halogen.However, when X is hydrogen, at least one of R_1, R_2, R_3, R_4, R_5 and R_6 represents an allyl group) was used. Recording material featuring.