JP2844364B2 - Novel fluoran compound, method for producing the same, and recording material using the compound - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fluoran compound, a method for producing the same, and a recording material using the compound. More particularly, the present invention relates to a novel fluoran compound which reacts with an acidic substance to develop a red color, a method for producing the same, and a recording material such as a pressure-sensitive recording material and a heat-sensitive recording material using the compound.

2. Description of the Related Art In a recording material such as a pressure-sensitive recording material and a heat-sensitive recording material, 2-chloro-6-diethylamino-3-methylfluoran reacts with an acidic substance to produce a red color. Used for the body.

However, the recording material has a problem of background coloring because the reactivity between the chromogen and the acidic substance is too high.

Accordingly, there is an increasing demand for a chromogen that reacts with an acidic substance and develops a red color to provide a recording material having a high degree of whiteness of the background.

Means for Solving the Problems As a result of intensive studies on the development of a novel chromogen, the present inventors have found that a fluoran compound represented by the general formula (I) is useful for recording materials such as pressure-sensitive recording materials and heat-sensitive recording materials. And completed the present invention.

[Wherein, R ₁ and R ₂ independently represent a straight-chain or branched alkyl having 1 to 5 carbon atoms, and R ₃ represents a straight-chain or branched alkyl having 1 to 5 carbon atoms, or benzyl. Shows, R ₁ and R ₂
May combine to form a 5- or 6-membered heterocyclic ring. Specific examples of R ₁ and R ₂ include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl and isopentyl. Specific examples of R ₃ include methyl,
There are ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, pentyl, isopentyl, tertiary pentyl and benzyl. Also, R ₁
R ₂ combines to form a pyrrolidino and piperidino group.

The fluoran compound represented by the general formula (I) is a novel compound newly produced by the present inventors, and is a substantially colorless or slightly colored solid, but reacts with an acidic substance to form a red color. Gives a recording material having a high degree of background whiteness.

The fluoran compound of the present invention can provide a wider color tone by using another chromogen in combination.

Table 1 shows the test results of the background whiteness and the background stability of the thermosensitive recording materials using the compounds (A) and (B) of the present invention and the existing compound (C).

The background coloration was measured using Macbeth RD-914.

The stability test was performed by irradiating the test paper with a fluorescent lamp of about 20,000 lux for 96 hours.

From Table 1, it is clear that the heat-sensitive recording material using (A) and (B) is superior to the heat-sensitive recording material using (C) in the background whiteness and the background stability.

The present invention provides two methods for producing the fluoran compound represented by the general formula (I).

In the first production method, the fluoran compound is produced by reacting a compound represented by the general formula (II) with a compound represented by the general formula (III) in sulfuric acid, followed by treating with a base aqueous solution such as caustic soda. Is done.

Wherein R ₁ , R ₂ and R ₃ are the same as above. In the second production method, the fluoran compound is produced by reacting the compound represented by the general formula (IV) with an alkyl halide, aralkyl halide or dialkyl sulfate in an inert solvent in the presence of a base. .

Wherein R ₁ and R ₂ are the same as described above. Examples of the alkyl halide effective in the present invention include ethyl iodide, propyl iodide, butyl iodide, pentyl iodide, propyl bromide, butyl bromide, pentyl bromide, butyl chloride, pentyl chloride and isomers thereof. There is. Aralkyl halides include benzyl chloride and benzyl bromide. Dialkyl sulfates include dimethyl sulfate, diethyl sulfate and dibutyl sulfate. Examples of the inert solvent include benzene, toluene, xylene, benzene chloride, 1,2-dichloroethane, and tetrahydrofuran. Examples of the base include calcium carbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, and magnesium oxide.

The compounds of the present invention are extremely useful for pressure-sensitive recording materials and heat-sensitive recording materials.

Various known methods can be used for producing pressure-sensitive recording materials and heat-sensitive recording materials. For example, JP-B-46-4614 can be used for producing a pressure-sensitive recording material, and JP-B-45-14039 can be used for producing a thermosensitive recording material.

Pressure sensitive recording materials usually consist of two sheets of paper. The upper paper has a back surface coated with a capsule containing at least one chromogen solution dissolved in a solvent such as diallylalkane or alkylnaphthalene. The lower paper is coated on its surface with an acidic substance such as Shilton Clay or phenolic polymer. When pressurized, the capsule in the pressurized portion is broken. Thereby, the image forming components react to form a clear image on the surface of the lower sheet.

Thermal recording materials usually consist of one sheet of paper. On the surface of the paper, an image forming component consisting of a chromogen and an acidic substance such as bisphenol A, bisphenol S, benzyl p-hydroxybenzoate is applied together with additives such as calcium carbonate, zinc stearate, and paraffin wax. Have been. When heated, the heated image forming components react to form a clear image.

The present invention provides a novel red-colored chromogen, two methods for producing the compound, and a recording material having high background whiteness using the compound.

Examples Hereinafter, the present invention will be described specifically with reference to Examples.
The embodiments are not all and the present invention is not limited to the embodiments. Unless specifically supported, parts and percentages indicate parts by weight and% by weight.

Example 1 Preparation of 6-diethylamino-2- (4-ethoxyphenyl) sulfonylfluoran 16 parts of 2- (4-diethylamino-
2-hydroxybenzoyl) benzoic acid and 15 parts of 4-
Ethoxyphenylsulfone was dissolved sequentially at 20-23 ° C. The mixture was stirred at room temperature for 24 hours and then discharged into 500 parts of ice water. The precipitate was collected by filtration and washed with water. Then
The filter cake was stirred and refluxed with 300 parts of toluene and 100 parts of a 20% aqueous sodium hydroxide solution for 2 hours. The toluene layer was separated, washed with hot water, and filtered. After distilling off the toluene,
The residue was refluxed with 100 parts of methanol to give 14 parts of the title compound. A slightly pink powder with a melting point of 267.
5-271.5 ° C. The mass spectrum showed a molecular weight of 555, and the result of elemental analysis agreed well with the calculated value.

C H N Calculated _{(C 32 H 29 NO 6 S} ) 69.16% 5.27% 2.52% Found 69.21% 4.98% 2.86% Example 2 2- (4-benzyloxy-phenylalanine) Surufuoniru -6
Preparation of di-n-butylaminofluoran 37 parts of 2- (4-di-n-butylamino-2-hydroxybenzoyl) benzoic acid and 25 parts in 120 parts of concentrated sulfuric acid
Part of 4-hydroxyphenylsulfone at 20 to 23 ° C.
And dissolved. After stirring this mixture at room temperature for 24 hours,
Discharged into 500 parts of ice water. The precipitate was collected by filtration and washed with water.
The filter cake was dispersed in 100 parts of water and neutralized with a 5% aqueous sodium hydroxide solution. The solid was collected by filtration, washed with water, dried, and then purified by column chromatography to obtain 24 parts of 6-di-n-butylamino-2- (4-hydroxyphenyl) sulfonylfluoran. It was a red powder with a melting point of 91 ° C (decomposition). The mass spectrum showed a molecular weight of 583, and the elemental analysis results agreed well with the calculated values.

C H N Calculated _{(C 34 H 33 NO 6 S} ) 69.95% 5.71% 2.40% Found 70.04% 5.90% 2.24% Then, 2.4 parts of 6-di -n- butylamino-2-
(4-hydroxyphenyl) sulfonylfluoran,
2.3 parts of benzyl bromide and 14 parts of calcium carbonate in 100 parts
In 50 parts of tetrahydrofuran for 5 hours.
After the solids were filtered off, the filtrate was concentrated and purified by column chromatography to give 1.6 parts of the title compound. It was a white powder with a melting point of 169.3-170.6 ° C. The mass spectrum showed a molecular weight of 673, and the elemental analysis results agreed well with the calculated values.

C H N Calculated _{(C 41 H 39 NO 6 S} ) 73.07% 5.85% 2.08% Found 72.84% 5.88% 1.95% Example 3 2- (4-ethoxy-phenylalanine) Surufuoniru -6 pyrrolidinopyridine fluoran manufacturing 9.3 parts of 2- (2-hydroxy-4) in 60 parts of concentrated sulfuric acid.
-Pyrrolidinobenzoyl) benzoic acid and 9.2 parts of 4-
Ethoxyphenylsulfone was dissolved sequentially at 20-23 ° C. The mixture was stirred at room temperature for 24 hours and then discharged into 500 parts of ice water. The precipitate was collected by filtration and washed with water. The filter cake was stirred and refluxed with 400 parts of toluene and 100 parts of a 20% aqueous sodium hydroxide solution for 2 hours. Separate the toluene layer,
After washing with hot water, the mixture was filtered. After concentration of the filtrate, the residue was purified by column chromatography to obtain 14 parts of the title compound. It was a white powder with a melting point of 251-254 ° C. The mass spectrum showed a molecular weight of 553, and the result of elemental analysis agreed well with the calculated value.

C H N Calculated for _{(C 32 H 27 NO 6 S} ) 69.41% 4.93% 2.53% partial sodium salt of preparation 5 parts of polyvinyl benzenesulfonic Huong acid Found 70.16% 4.99% 2.70% Example 4 a pressure-sensitive recording material It was dissolved in 95 parts of hot water, cooled, and adjusted to pH 4 with aqueous sodium hydroxide solution. Then, a solution prepared by dissolving 3 parts of 6-diethylamino-2- (4-ethoxyphenyl) sulfonylfluoran in 47 parts of phenylxylylethane is added, and the oil droplets become 4 μm with a homomixer. Until emulsified. After the addition of 10 parts of the melamine-formaldehyde prepolymer, the mixture was heated to 60 ° C. with stirring and stirred for 2 hours. It is then cooled to room temperature and pH 7.5 with 25% ammonia.
To obtain a white emulsion.

10 parts of the emulsion, 2 parts of flour starch and 1 part of latex are mixed and coated on a high-quality paper with a # 16 Meyer bar so that the coating amount after drying is about 5 g / m ^2. I got

When the upper paper was overlaid on the lower paper coated with Shilton Clay or phenolic polymer and pressed by hand, a clear red image was formed on the lower paper.

Example 5 Production of heat-sensitive recording material The following two components were individually ground with an attritor to obtain dispersions A and B.

[Dispersion B]

Bisphenol A 10 p-Benzylbiphenyl 10 Calcium carbonate 10 5% aqueous solution of polyvinyl alcohol 100 Then, 12 parts of dispersion A, 52 parts of dispersion B and 5 parts of hydrin P-7 (30% paraffin wax emulsion) The mixture was mixed with high-quality paper and dried with a # 16 Meyer bar so that the coating amount after drying was about 6 g / m ² . After the coated paper was dried, it was calendered so as to have a tack smoothness of about 400 seconds to obtain a heat-sensitive recording material having high background whiteness.

Further, instead of 6-diethylamino-2- (4-ethoxyphenyl) sulfonylfluoran, 2- (4-
(Benzyloxyphenyl) sulfonyl-6-di-n-
Using butylaminofluoran and 2- (4-ethoxyphenyl) sulfonyl-6-pyrrolidinofluoran, respectively, two kinds of heat-sensitive recording materials were obtained in the same manner as described above.

These three types of heat-sensitive recording materials formed clear red images when heated with a thermal head or a hot pen.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-1-128984 (JP, A) JP-B-56-50879 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) C07D 493/10 B41M 5/12 C09B 11/28 CA (STN) REGISTRY (STN)

Claims (6)

(57) [Claims] 1. A fluoran compound represented by the general formula (I). [Wherein, R ₁ and R ₂ independently represent a straight-chain or branched alkyl having 1 to 5 carbon atoms, and R ₃ represents a straight-chain or branched alkyl having 1 to 5 carbon atoms, or benzyl. Shows, R ₁ and R ₂
May combine to form a 5- or 6-membered heterocyclic ring. ] 2. A process for producing a fluoran compound represented by the general formula (I), comprising reacting a compound represented by the general formula (II) with a compound represented by the general formula (III). [Wherein, R ₁ and R ₂ independently represent a straight-chain or branched alkyl having 1 to 5 carbon atoms, and R ₃ represents a straight-chain or branched alkyl having 1 to 5 carbon atoms, or benzyl. Shows, R ₁ and R ₂
May combine to form a 5- or 6-membered heterocyclic ring. ] 3. A process for producing a fluoran compound represented by the general formula (I), comprising reacting a fluoran compound represented by the general formula (IV) with an alkyl halide, benzyl halide or dialkyl sulfate. [Wherein, R ₁ and R ₂ independently represent a straight-chain or branched alkyl having 1 to 5 carbon atoms, and R ₃ represents a straight-chain or branched alkyl having 1 to 5 carbon atoms, or benzyl. Shows, R ₁ and R ₂
May combine to form a 5- or 6-membered heterocyclic ring. ] 4. A recording material comprising a color development reaction between a fluoran compound represented by the general formula (I) and an acidic substance. [Wherein, R ₁ and R ₂ independently represent a straight-chain or branched alkyl having 1 to 5 carbon atoms, and R ₃ represents a straight-chain or branched alkyl having 1 to 5 carbon atoms, or benzyl. Shows, R ₁ and R ₂
May combine to form a 5- or 6-membered heterocyclic ring. ] 5. The recording material according to claim 4, which is a pressure-sensitive recording material. 6. The recording material according to claim 4, which is a thermosensitive recording material.