JPH0820730A - Chromogenic composition - Google Patents

Abstract

(57) [Summary] [Structure] The composition ratio of the carboxylate represented by the general formula (1) and the succinyl succinate represented by the general formula (2) is 1: 0.1 to 1:10. A color-forming composition having a molar ratio and a heat-sensitive recording material in which the composition is supported on a support. Embedded image [In the formula, R ¹ represents an alkyl group having 1 to 20 carbon atoms, a phenyl group which may have a substituent, an aralkyl group or an alkenyl group. ] [Chemical 2] [In the formula, R ² represents a hydroxyalkyl group having 1 to 20 carbon atoms. [Effect] According to the present invention, a heat-sensitive recording material having excellent color development sensitivity and extremely excellent color image fastness can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color forming composition and a heat-sensitive recording material using the color forming composition, which is excellent in color forming sensitivity and color image stability.

[0002]

2. Description of the Related Art In recent years, heat-sensitive recording materials, which have been rapidly used in large amounts, can easily obtain clear color images with a simple device. Therefore, facsimile paper, word processor paper, chart paper for various analytical instruments, tickets, It is widely used as a commuter pass, prepaid card, tag, etc. On the other hand, in the recording layer of these heat-sensitive recording materials, a phthalide-based or fluoran-based leuco dye is used as a color former, and it is well known that the color development image of the dye with a phenolic developer has a problem of fastness. Is a fact of. In other words, it has the drawback of fading due to sunlight, light from fluorescent lamps, alcohols contained in cosmetics, plasticizers contained in resin films and erasers.

In order to overcome these drawbacks, various studies have been made so far. One of them is an attempt to generate phthalocyanine from a phthalocyanine precursor by a reaction by heat, for example, in Japanese Patent Publication No. 58-8357.
-Amino-3-iminoisoindolenin or a derivative thereof and an organic acid metal salt or a metal complex salt compound are used in the heat-sensitive layer, but a metal compound having low sensitivity and adversely affecting the environment may be used. It was a problem.

Further, Japanese Patent Publication No. 4-16353 discloses that
A compound carrying an imino compound such as 1,3-diiminoisoindoline is disclosed. The sensitivity was low when only the diiminoisoindoline compound was carried.

Recently, Japanese Patent Application No. 6-8 disclosed by the present inventors.
Japanese Patent No. 8426 describes a heat-sensitive recording material using a carboxylic acid salt of a 1,3-diiminoisoindoline, but it is hard to say that the color developing sensitivity is extremely excellent, and it is not suitable for a commercially available word processor or facsimile. However, there is a drawback that the color density of the thermal head is still insufficient.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color forming composition which forms a color image with a small amount of heat energy and which shows high fastness.

[0007]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventor has completed the present invention by using the color forming composition described below.

That is, the present invention is based on the general formula (1)

[0009]

Embedded image [In the formula, R ¹ represents an alkyl group having 1 to 20 carbon atoms, a phenyl group which may have a substituent, an aralkyl group or an alkenyl group. ] And a carboxylate represented by the general formula (2)

[0010]

[Chemical 4] [In the formula, R ² represents a hydroxyalkyl group having 1 to 20 carbon atoms. ] The composition ratio with succinyl succinate represented by the present invention relates to a color forming composition having a molar ratio of 1: 0.1 to 1:10.

The present inventors have already confirmed that the developed color image is stable, and the thermochromic reaction between the carboxylate of the diiminoisoindoline derivative and the carbonyl compound having a hydrogen atom at the α-position. As a result of further research, it was found that a monoester of succinic acid as a carboxylic acid was effective in improving the sensitivity of this color-developing system, and in a carbonyl compound having a hydrogen atom at the α-position, bis (hydroxyalkyl) was used. ) We have found that succinyl succinate is effective in improving sensitivity.

The compound represented by the general formula (1) is 1,3
-Diiminoisoindoline and succinic acid monoester,
It can be obtained by mixing in a solvent or without solvent, and optionally heating.

When there is no commercial product of succinic acid monoester, it can be easily synthesized by mixing and heating succinic anhydride and alcohol.

The notation of the carboxylate compound represented by the general formula (1) of the present invention is as follows.

[0015]

Embedded image Or

[0016]

[Chemical 6] Or

[0017]

[Chemical 7] You can write it like this, but the meaning is the same.

Specific examples of the carboxylic acid salt represented by the general formula (1) include 1,3-diiminoisoindoline / succinic acid monomethyl ester salt and 1,3-diiminoisoindoline / succinic acid monoethyl ester. Salt, 1,3-diiminoisoindoline / succinic acid mono-n-propyl ester salt,
1,3-diiminoisoindoline / succinic acid monoisopropyl ester salt, 1,3-diiminoisoindoline / succinic acid mono-n-butyl ester salt, 1,3-diiminoisoindoline / succinic acid monoisobutyl ester salt, 1,3
-Diiminoisoindoline / succinic acid mono-sec-butyl ester salt, 1,3-diiminoisoindoline / succinic acid mono-t-butyl ester salt, 1,3-diiminoisoindoline / succinic acid mono-n-amyl ester salt 1,3-diiminoisoindoline / succinic acid monoisoamyl ester salt, 1,3-diiminoisoindoline / succinic acid mono se
c-amyl ester salt, 1,3-diiminoisoindoline / succinic acid mono t-amyl ester salt, 1,3-diiminoisoindoline / succinic acid mono n-hexyl ester salt, 1,3-diiminoisoindoline -Succinic acid monocyclohexyl ester salt, 1,3-diiminoisoindoline-succinic acid mono (4-methylcyclohexyl) ester salt, 1,3-diiminoisoindoline-succinic acid mono (4
-Ethylcyclohexyl) ester salt, 1,3-diiminoisoindoline / succinic acid mono n-heptyl ester salt, 1,3-diiminoisoindoline / succinic acid mono n-
Octyl ester salt, 1,3-diiminoisoindoline / succinic acid mono t-octyl ester salt, 1,3-diiminoisoindoline / succinic acid mono n-decyl ester salt,
1,3-diiminoisoindoline, succinic acid mono-n-undecyl ester salt, 1,3-diiminoisoindoline
Succinic acid mono n-dodecyl ester salt, 1,3-diiminoisoindoline / succinic acid mono n-hexadecyl ester salt, 1,3-diiminoisoindoline, succinic acid mono n-
Heptadecyl ester salt, 1,3-diiminoisoindoline / succinic acid monooleyl ester salt, 1,3-diiminoisoindoline / succinic acid monostearyl ester salt,
1,3-Diiminoisoindoline / succinic acid monophenyl ester salt, 1,3-Diiminoisoindoline / succinic acid mono o-toluyl ester salt, 1,3-Diiminoisoindoline / succinic acid m-toluyl ester Salt, 1,3
-Diiminoisoindoline / succinic acid mono p-toluyl ester salt, 1,3-diiminoisoindoline / succinic acid mono o-chlorophenyl ester salt, 1,3-diiminoisoindoline / succinic acid mono m-chlorophenyl ester salt , 1,3-Diiminoisoindoline / succinic acid mono p-
Chlorophenyl ester salt, 1,3-diiminoisoindoline / succinic acid mono o-methoxyphenyl ester salt,
1,3-diiminoisoindoline / succinic acid mono m-methoxyphenyl ester salt, 1,3-diiminoisoindoline / succinic acid mono p-methoxyphenyl ester salt,
1,3-Diiminoisoindoline / succinic acid monobenzyl ester salt, 1,3-Diiminoisoindoline / succinic acid monophenethyl ester salt, 1,3-Diiminoisoindoline / succinic acid mono (3-phenylpropyl) Ester salts.

The compound represented by the general formula (2) undergoes dehydration condensation cyclization reaction of succinic acid diethyl ester in the presence of sodium ethylate to give 2,5-diethoxycarbonyl-1,4-cyclohexanedione. After it is obtained, it may be reacted with a diol to obtain it by a transesterification reaction, or the succinic acid dihydroxyalkyl ester may be obtained by a dehydration condensation cyclization reaction in the presence of a corresponding diol monoalcoholate.

The general formula (2) is described as a keto type of keto-enol equilibrium, but includes all conceivable enol types.

Specific examples of the succinyl succinate represented by the general formula (2) include bis (hydroxymethyl) succinyl succinate, bis (hydroxyethyl) succinyl succinate and bis (hydroxy-n-propyl) succinyl succinate. , Bis (hydroxyisopropyl) succinyl succinate, bis (hydroxy-
n-butyl) succinyl succinate, bis (hydroxyisobutyl) succinyl succinate, bis (hydroxy-sec-butyl) succinyl succinate, bis (hydroxy-t-butyl) succinyl succinate,
Bis (hydroxy-n-amyl) succinyl succinate, bis (hydroxyisoamyl) succinyl succinate, bis (hydroxy-t-amyl) succinyl succinate, bis (hydroxy-n-hexyl) succinyl succinate, bis (4-hydroxy) Cyclohexyl) succinyl succinate, bis [4- (hydroxymethyl) cyclohexylmethyl] succinyl succinate, bis (3-hydroxy-2,2-dimethylpropyl) succinyl succinate, bis (hydroxy-n-
Octyl) succinyl succinate, bis (hydroxy-n-decyl) succinyl succinate, bis (hydroxy-n-dodecyl) succinyl succinate, bis (hydroxy-n-hexadecyl) succinyl succinate, bis (hydroxystearyl) succinyl succinate Is mentioned.

The color-developing composition of the present invention can be carried on a normally solid support and heat energy is applied thereto to form a dark blue to black color-developing material.

The heat source may be one that directly transfers heat such as a thermal head used in a printer such as a facsimile machine, or one that is converted into heat energy such as laser light. Good.

The case where the color forming composition is used as a thermosensitive recording material will be described below as an example.

The heat-sensitive recording material comprises a support and a recording layer on which a colored state can be realized by heat.

As the support, paper, synthetic paper, synthetic resin film, laminated paper, non-woven sheet or the like is used according to the purpose.

The recording layer can basically be composed of the color forming composition of the present invention and a binder. The color forming composition is dispersed in a binder solution with an attritor or a sand mill to obtain a heat-sensitive coating liquid, but it is also possible to mix the components after dispersing them. In this case, the carboxylic acid salt represented by the general formula (1) and the succinyl succinate represented by the general formula (2) may be in the form of fine particles in a dispersed state, or may be completely dissolved and thus in a solution state. May be
A recording layer can be formed by coating the resulting heat-sensitive coating liquid on a support and drying.

The composition ratio of the carboxylic acid salt of the present invention to succinyl succinate is preferably 1: 0.1 to 1:10, more preferably 1: 0.4 to 1: 4. The weight of the color forming composition and the binder is 1: 1 to 1: 0.00.
5 is preferable, and 1: 0.5 to 1: 0.01 is more preferable.

In this recording layer, a melting point depressant, an ultraviolet absorber, an antioxidant, organic and inorganic pigments and the like can be added depending on the purpose.

Examples of the melting point depressant include paraffin wax, polyethylene wax, waxes such as higher fatty acids and their esters, acid amides such as stearic acid amide, diphenyls such as 4,4′-dimethylbiphenyl, and methylolamide. , Naphthalenes such as 1,3-dinitronaphthalene, ureas, acids such as phthalic anhydride, anilides such as acetanilide, benzanilide, alkylcarboxylic acid anilide, triphenyls, phthalonitriles, bisresorcinol ethylene Ethers such as ether, salicylic acid derivatives such as 4-t-butyl salicylate, ethyl-2-cyano-
3,3-diphenyl acrylate, benzotriazoles, fluorene, dimethyl isophthalate, diphenyl sulfone, mandelic acid, benzoin, ethylanthraquinone, coumarone compounds, carbazoles such as N-ethylcarbazole, sulfonamides, triphenylmethanes, Thiazoles such as dibenzothiazyl disulfide, sulfenamides such as N-cyclohexyl-2-benzothiazolylsulfenamide, thiurams such as tetramethylthiuram disulfide, dithioates such as zinc dibutyldithiocarbamate. , Guanidines such as diphenylguanidine, thioureas such as N, N-diphenylthiourea, phenylhydrazide derivatives of carboxylic acids, p-hydroxybenzoic acid esters, N, N-di Amides such as E sulfonyl formamide, and the like.

Examples of the UV absorbers include benzotriazole and its derivatives, benzoin and its derivatives, 2-chloroanthraquinone, benzol peroxide, salicylates such as p-t-butylphenyl salicylate, and ethyl diphenylacrylate. Examples include cyanoacrylates.

Antioxidants include 2,6-di-t-butyl-4-methylphenol and di (3-t-butyl-4).
-Hydroxy-5-methylphenyl) thioether,
1,1-bis (2-methyl-4-hydroxy-5-t-
Hindered phenols such as butylphenyl) butane, di (2,2,6,6-tetramethyl-4 sebacate)
Hindered amines such as piperidine).

As the pigment, talc, clay, silica,
Examples include calcined kaolin, zinc oxide, silicon oxide, titanium oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, and urea-formalin resin.

Water and organic solvents (toluene, methanol, ethanol, isopropyl alcohol, n-hexane, cyclohexane, n-) are used as the dispersion medium of the binder solution.
(Octanol, ethylcyclohexane, dioxane, etc.)
Is used.

When the dispersion medium is water, the binder is polyvinyl alcohol resin, methyl cellulose resin, hydroxyethyl cellulose resin, carboxymethyl cellulose resin, methyl vinyl ether / maleic anhydride copolymer resin, polyacrylic acid resin, polyvinyl pyrrolidone resin, acrylic resin. Amide resin, gelatin, gum arabic, etc. can be used.

As the binder when the dispersion medium is an organic solvent, alkyd resin, vinyl chloride resin, urethane resin,
Xylene resin, phenol resin, coumarone resin, vinyltoluene resin, terpene resin, vinyltoluene / butadiene copolymer resin, vinyltoluene / acrylate copolymer resin, styrene / acrylate copolymer resin, vinyl / isobutyl ether copolymer resin Etc. can be used.

A protective layer may be provided on the recording layer and an undercoat layer may be provided below the recording layer.

For the protective layer, urethane resin, polyolefin resin, polyester resin, vinyl resin, epoxy resin, acrylic resin can be used.

For the undercoat layer, heat-insulating fine hollow particles, calcined kaolin, organic pigments, heat-expandable microcapsules and the like can be used in order to improve color developability.

Although the recording method utilizing the formation of a coloring material by heat has been described above, it is also possible to use it in combination with other recording methods such as magnetic recording, metal thin film recording and cloudy recording.

As the use of the color-forming composition of the present invention, the heat-sensitive recording material is shown above, but the color-forming composition of the present invention can be dissolved or dispersed in a solvent to be used as an ink or a paint. If the color-forming composition is dissolved in a solvent, a colorless ink or a white ink or paint is obtained. Such a paint can be used to determine whether or not the heat treatment has been completed. For example,
When producing canned food, bottled food, etc. and rubber,
If it is applied to a part of a can, a bottle, or rubber, there is no change in the untreated one, and the heat-treated one develops from blue to a dark color of black, so it can be distinguished at a glance.

Further, the color-forming composition of the present invention can be used by making use of its fastness. For example, heat energy is applied to the color forming composition of the present invention to obtain a dark and fast color developing body.
This color-developing material is crushed to obtain an organic pigment. When a paint is manufactured using this organic pigment, a robust paint having a strong near infrared absorption ability can be obtained.

[0043]

EXAMPLES Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

Prior to the examples, synthetic examples of carboxylate and succinyl succinate are shown.

(Synthesis example 1) Synthesis of 1,3-diiminoisoindoline / succinic acid monoethyl ester salt 11.68 g (0.08 mol) of succinic acid monoethyl ester was dissolved in 200 ml of ethyl acetate and stirred. To 1,
11.60 g of 3-diiminoisoindoline was added.
After refluxing for 10 minutes, the mixture was cooled to room temperature with stirring, and the generated precipitate was filtered off. After drying, 22.12 g (yield 95%) of the desired product was obtained as a pale yellowish white powder. Melting point 123-126
° C.

(Synthesis Examples 2 to 12) Synthesis of 1,3-diiminoisoindoline carboxylic acid salt Instead of the succinic acid monoethyl ester in Synthesis Example 1, the compounds shown in Table 1 were used, and Synthesis Example 1 was used. By the same operation as above, the corresponding carboxylic acid salts were obtained. The results are summarized in Table 1.

[0047]

[Table 1]

(Synthesis Example 13) Synthesis of bis (hydroxyethyl) succinyl succinate To 62 g (1 mol) of ethylene glycol, 0.08 g (2 mmol) of 60% sodium hydride was added and dissolved, and then diethyl succinyl succinate. 12.8 g (0.
(05 mol) was added, and the mixture was stirred at 145 to 150 ° C. for 6 hours while removing the separated ethanol. The reaction mixture was discharged into 60 ml of 0.12% dilute hydrochloric acid, and the formed precipitate was filtered off. After drying, 9.22 g (yield 64%) of the desired product was obtained as a white powder. The melting point was 137-139 ° C.

(Synthesis Examples 14 to 24) Synthesis of bis (hydroxyalkyl) succinyl succinate An ester prepared by the same procedure as in Synthesis Example 13 using the diols shown in Table 2 in place of the ethylene glycol in Synthesis Example 13. Exchange reactions were performed to obtain the corresponding succinyl succinates. The results are summarized in Table 2.

[0050]

[Table 2]

Example 1 1 part of 1,3-diiminoisoindoline / succinic acid monoethyl ester salt and 1 part of bis (hydroxyethyl) succinyl succinate were added to 20 parts of a 5% aqueous polyvinyl alcohol solution, and a sand mill was used. It was ground for 2 hours to prepare a heat-sensitive coating liquid. This heat-sensitive coating liquid was applied to a high-quality paper with Meyer bar No. 10 was applied and dried so that the solid content coating amount was 6 g / m ² to obtain a heat-sensitive recording material.

Example 2 In Example 1, 1,3-
1,3-Diiminoisoindoline / succinic acid mono-n-butyl ester salt was used in place of diiminoisoindoline / succinic acid monoethyl ester salt, and bis (4) was used in place of bis (2-hydroxyethyl) succinyl succinate. −
A heat-sensitive recording material was obtained in the same manner as in Example 1 except that (hydroxybutyl) succinyl succinate was used.

(Embodiment 3) In Embodiment 1, 1,3-
1,3-Diiminoisoindoline / succinic acid monoisopropyl ester salt was used in place of diiminoisoindoline / succinic acid monoethyl ester salt, and bis (6-hydroxyethyl) succinyl succinate was used instead of bis (6
A thermosensitive recording material was obtained in the same manner as in Example 1, except that -hydroxyhexyl) succinyl succinate was used.

Comparative Example 1 In Example 1, 1,3-
1,3-Diiminoisoindoline / succinic acid benzoate was used in place of diiminoisoindoline / succinic acid monoethyl ester salt, and di-n-octylsuccinyl succinate was used in place of bis (2-hydroxyethyl) succinyl succinate. A heat-sensitive recording material was obtained in the same manner as in Example 1 except that the nate was used.

(Comparative Example 2) In Example 1, 1,3-
Diiminoisoindoline / succinic acid monoethyl ester salt was replaced with 1,3-diiminoisoindoline / succinic acid monostearyl salt, and bis (2-hydroxyethyl)
A heat-sensitive recording material was obtained in the same manner as in Example 1 except that diethyl succinyl succinate was used instead of succinyl succinate.

(Evaluation) Examples 1 to 3 and Comparative Examples 1 and 2
With respect to the heat-sensitive recording material obtained in 1., its color development sensitivity and color image fastness were measured and are shown in Table 3.

The fastness was evaluated by the residual rate shown in the following formula. Residual rate (%) = (colored image density after test / colored image density before test) × 100 The density is measured by a Macbeth densitometer (TR-254 type) and represents an OD value when an amber filter is used. . Color development sensitivity The thermosensitive recording material was represented by the temperature of the hot iron when the OD value was 1.1 to 1.2. 2 UV carbon arcs (made by Suga Test Instruments Co., Ltd.) on the color image of the light resistance test
It was represented by the residual rate after irradiation for 4 hours. In the moist- heat resistance test color image, the density after keeping at 60 ° C. and 90% relative humidity for 24 hours was measured to obtain the residual rate. DOP stability test The color development image was overlaid with the paper coated with the capsule coating solution containing dioctyl phthalate, passed through a pressure roll, and the concentration was measured after keeping it at 25 ° C for 1 week. I asked. High wrap stability test Contact high wrap (made by Mitsui Toatsu Chemicals) with the developed color image, 1
The concentration was measured after applying a load of 00 g / cm ² and maintaining the temperature at 40 ° C. for 24 hours, and the residual rate was obtained.

[0058]

[Table 3]

[0059]

As is apparent from Table 3, the heat-sensitive recording material using the color-forming composition of the present invention is very useful because it has excellent color-developing sensitivity and color image fastness.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location C09K 9/02 C // C07C 69/40 9546-4H 69/757 C 9546-4H (72) Invention Bunji Sawano 43-43 Minami, Yugemachi, Yao-shi, Osaka Prefecture Yamamoto Kasei Co., Ltd.

Claims (2)

[Claims] 1. A compound represented by the general formula (1): [In the formula, R ¹ represents an alkyl group having 1 to 20 carbon atoms, a phenyl group which may have a substituent, an aralkyl group or an alkenyl group. ] And a carboxylic acid salt represented by the general formula (2): [In the formula, R ² represents a hydroxyalkyl group having 1 to 20 carbon atoms. ] The composition ratio with succinyl succinate represented by] is a molar ratio of 1: 0.1 to 1:10. 2. A heat-sensitive recording material comprising a support and the color-forming composition according to claim 1 supported on the support.