JPS58126192A - Recording medium - Google Patents

Abstract

PURPOSE:To obtain a recording medium excellent in heat-sensitive, color-forming sensitivity and storage stability by providing a recording layer containing a diazonium compound, a coupling agent subjected to neutralizing treatment, and an acid stabilizer on a support. CONSTITUTION:A coating liquid is obtained by dissolving a diazonium compound (A) (e.g., 4-diazo-N,N-diethylaniline), a coupling agent (B) obtained by subjecting an acid or basic coupling substance with carboxyl group or molecular base as substituent (e.g., 2-hydroxy-6-naphthoic acid) to a neutralization treatment with an inorganic or organic acid, an acid stabilizer (C) (e.g., citric acid), and a high- molecular binder (D) (e.g., PVA) in water. The coating liquid is applied on a support and dried to obtain a recording layer. Thus, a recording medium capable of forming images of azo dye by the azo coupling reaction of the diazonium compound and the coupling agent by heating, containing no color forming aid to generate alkali when heated, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording medium using a new heat-developable diazo-type recording material capable of fixing (referring to treatment to prevent uncolored areas from developing color even when heat is applied). It is.

Conventionally, there are many known image recording methods for converting information into visible images. In general.

Images are formed by causing physical or chemical changes in response to energy such as light, radiation, electrolysis, magnetism, heat, or pressure.

For example, recording methods that use heat include melting and sublimation.

There are two types: one that forms an image using physical changes such as volatilization, and one that forms an image using color development due to chemical changes caused by heat. but.

Since such a heat-sensitive recording material is configured to obtain a recorded image using heat, it has the ability to develop color even in non-image areas when heat is applied later. Therefore, if it is mistakenly brought close to a heat source, it will develop color and lose its ability as a recording medium, which is a defect due to the structure of the thermal recording medium. Therefore, improvements in this respect are desired in the general market.

Therefore, in recent years, a heat-developable diazo type recording material, which is a dry imaging system, has attracted attention as a heat-sensitive recording material, and development is progressing toward practical use.

Here, heat-developable diazo type recording bodies can be roughly classified into three types. namely, the alkali precursor type, the force-puller precursor type, and the diazo precursor type. These three types of image forming methods are the same in terms of phenomena. First, a diazo compound and a coupler cause a coupling reaction using thermal energy to form an image with an azo dye, and then the entire surface is irradiated with light energy. The coloring ability of the unpainted area is lost and fixed, forming a permanent image. The difference between the three types of image forming methods is the method of inducing the coupling reaction. In detail, in the alkali precursor type, the coloring aid undergoes chemical changes such as decomposition, dissociation, and melting due to thermal energy, and the recording layer is placed in an alkaline atmosphere, and the diazo compound and coupler cause a coupling reaction, and the azo dye It is a method of forming an image. The coupler precursor type is a method in which a coupler that is inactive in coupling reaction at normal temperatures is activated by thermal energy to cause a coupling reaction with a diazo compound to form an azo dye image.

The diazo precursor type is a method that utilizes the structural isomerization reaction of diazosulfonate by light. The anti-type diazosulfonate, which is inactive for coupling reaction, isomerized to the active syn-type by light energy, and the coupling reaction with the coupler is carried out by thermal energy. This is a method in which an image is formed using an azo dye.

Heat-developable diazo type recording materials using the above three types are already known, and numerous patents have been issued. For example, as an alkali precursor type, U.S. Pat.
48, Japanese Patent Publication No. 49-3926, etc., heat-developable diazo type recording materials using various coloring aids are described.

Special Publication No. 45-40153 as a coupler precursor type
Publication No. 11797, Special Publication No. 11797, Special Publication No. 11797, Special Publication No. 11797-
Publication No. 1562, Special Publication No. 1973. Japanese Patent Application No. 14522 describes a heat-developable diazo type recording material using a 2,3-dihydroxybenzoic acid derivative as a coupler which is activated by thermal energy. As for the diazo precursor type, diazosulfonate compounds, coupling agents, and polymer binders are disclosed in US Pat. A recording body made of the agent and a recording method thereof are described.

However, these conventional heat-developable diazo recording materials,
Like the alkali precursor type, it has heat-sensitive coloring sensitivity but lacks storage stability, or conversely, like the coupler precursor and diazonium precursor types, it has storage stability but cannot obtain coloring sensitivity that is compatible with the mechanism. It had a drawback. For this reason, various improvements have been made and development is progressing toward practical application, but a practical heat-developable diazo type recorder that has both heat-sensitive coloring sensitivity and storage stability has not yet been completed. That is the current situation.

In view of the current situation, the present inventors have completed the present invention as a result of intensive research. That is, the present invention provides a recording layer containing a diazonium compound, a coupling agent obtained by neutralizing an acidic or basic coupling substance with an inorganic or organic base or acid, and an acid stabilizer on a support. This is a recording body with a distinctive feature.

The recording material constituting the recording layer of the present invention has, as basic constituents, a diazonium compound and an acidic coupling substance containing a carboxyl group as a substituent, which is neutralized with an inorganic or organic base.

It consists of a coupling agent in salt form and an acid stabilizer. However, organic bases that neutralize acidic coupling substances containing carboxyl groups as substituents include pulling substances containing molecular bases as substituents.

Furthermore, the recording material constituting the recording layer of the present invention has a diazonium compound as a basic component, and a coupling material in which a basic coupling substance containing a molecular base as a substituent is neutralized with an inorganic or organic acid to form a salt. It consists of an acid stabilizer and an acid stabilizer. However, the organic acids used to neutralize coupling substances containing molecular bases as substituents include acidic coupling substances containing sulfonic or carboxyl groups as substituents of thermally decomposable organic acids. .

The heat-developable diazo type recording material according to the present invention does not contain a coloring aid that generates alkali when heated, and when heated, the diazo compound and the coupling agent cause an azo coupling reaction to form an image using an azo dye. The present invention provides a recording material characterized by a coupling agent in the recording layer. The coupling agents can be formally classified into four types.

Namely.

Type 1: The carboxyl group of an acidic coupling substance containing a carboxyl group as a substituent is neutralized with an inorganic base to form a salt Type 2: Acidic coupling substance containing a carboxyl group as a substituent Type 4: Carboxyl groups are neutralized with an organic base to form a salt.The molecular base of a rasling substance is neutralized with an inorganic acid to form a salt.Type 4: A basic type containing a molecular base as a substituent. The molecular base of the coupling substance is neutralized with an organic acid to form a salt. Table 1 shows specific representative examples of each type.

Table 1. Classification of coupling agents and their specific examples The heat-developable diazo type recording material according to the present invention is a new type of heat-developable diazo type recording material using the above-mentioned coupling agent, unlike the conventional heat-developable diazo type recording material type described above. It is a diazo type recording material. In this image forming method, thermal energy causes a chemical reaction such as decomposition, melting, or dissociation of the coupling substance, creating a coupling-activating atmosphere in the recording layer, causing a coupling reaction with the diazo compound, and creating an image using an azo dye. It is something that forms. Furthermore, since the degree of coupling activity under heat varies depending on the type of inorganic or organic base or acid that forms a salt with an acidic or basic coupling substance, any thermal coloring sensitivity can be selected.

Specifically, the greater the acidity function in a basic solution of an inorganic or organic base that forms a salt with an acidic coupling substance, the greater the degree of coupling activity under heat. For example, the color development sensitivity of a heat-developable diazo type recording material using a salt of 2-hydroxy-3-naphthoic acid and lithium hydroxide or calcium hydroxide as a coupling agent is greater when using lithium hydroxide as an inorganic base. The value was shown. This result was a value consistent with the magnitude of the acidity function described above. Furthermore, the greater the vapor pressure or degree of thermal decomposition of the inorganic or organic acid that forms a salt with the basic coupling substance, the greater the degree of coupling activity under heat.

Specifically, the features of the recording medium of the present invention compared to conventional ones are as follows: 1) The recording layer does not contain a coloring aid that generates alkali when heated, and the coupling reaction with the diazo compound occurs when heated. This is a recording medium that generates azo dye.

2) It is a recording medium in which an arbitrary heat-sensitive coloring sensitivity can be selected by selecting a coupling agent.

5) Since the recording layer does not contain a color development aid and the recording layer is in an acidic atmosphere, the recording medium has excellent storage stability.

Therefore, the recording medium of the present invention has satisfactory storage stability and color development sensitivity, which have been difficult to put into practical use, and therefore can be used in a variety of applications. For example, it is particularly effective as a computer output printer, a data communication terminal, and for tickets, cards, and sticker-less commuter passes that require counterfeit prevention.

Here, the method of using the recording medium of the present invention is as follows:
Recording methods include a method using heat and light energy, in which an image is formed on the recording layer using thermal energy, and then the entire surface is irradiated with light energy to fix it, and a transparent original is brought into close contact with the recording layer, and light energy is applied to the image. A method using light and thermal energy is possible, in which a latent image is formed by irradiation and then developed by applying thermal energy to the entire surface.

However, as the energy source used here, a thermal head, a thermal pen, an infrared ray, a laser beam, a thermal roll, etc. can be used as a thermal energy source. Furthermore, a mercury lamp, a xenon lamp, a tungsten lamp, a xenon flasher, a laser, or the like can be used as a light source that generates light energy.

Each material used in the present invention will be described in detail below.

Various known diazo compounds can be used as the diazo compound used in the present invention. For example, Nokurafunilenediamine N-N-substituted compound (4-diarylene diamine N-N-diethylaniline etc.), aminohydroquinone ether type (4-diazo-2-1-diptoxy-)podiethylaniline%4 -Diazo-2-chloro-5methoxy-N-
pensoylaniline et c), aminodiphenyl, aminodiphenylamine and similar compounds (4-diazo-2-5-4'-triexydiphenylamine, etc.
).

Derivatives of heterocyclic amines (4-diazo-2-
5-di-f-toxy N-phenylmorpholine etc.). The diazo compounds described above are used as diazonium salts, which are relatively stable as sulfates or hydrochlorides, or as double salts with zinc chloride or the like. or,
Stabilization methods such as diazonium sulfonate and diazonium borofluoride can also be used.

The coupling agent used in the present invention is obtained by neutralizing an acidic or basic coupling substance with an inorganic or organic base or Wl. It can be used in the form of a salt by neutralization with a base or acid. A specific list of these coupling agents according to the types mentioned above is as follows. However, it is not limited to the coupling agents described.

Type 1: A coupling agent in which the carboxyl group of an acidic coupling substance containing a carboxyl group as a substituent is neutralized with an inorganic base to form a salt, i.e., 2-hydroxy-6-naphthoic acid, 2-hydroxy- 3-naphthoic acid, 2-hydroxy-1-naphthoic acid, 2,6-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,
4.6-) Dihydroxybenzoic acid, 2,6-cyhydroxy-3-methylbenzoic acid.

2.6-cyhydroxy-4-propylbenzoic acid, 2.6
-Syhydroxy-4-benzylbenzoic acid.

2.6-cyhydroxy-4-bromobenzoin M, 2.6
-Cyhydroxy-4-chromobenzoic acid, 2,6-cyhydroxy-4-iodobenzoic acid S 2,6-cyhydroxy-3,5-dibromobenzoic acid, 2,6-cyhydroxy-3,5-dichromebenzoic acid H, 2v 6 9 hydroxy-
3-ethyl-5-brobenzoic acid, 2. s-dihydroxy-3-benzyl-5-brombenzoic acid, 2,6-dihydroxy-3-(2-carboxylethyl)-benzoic acid, 2,6-cyhydroxy-4-methoxybenzoic acid, 2
, 6-cyhydroxy-4-methylbenzoic acid, 2,6-cyhydroxy-4-acetoxybenzoic acid, 2,6-cyhydroxy-4-amidobenzoic acid, 2,6-cyhydroxy-4-sulfobenzoic acid, 2,6-cyhydroxy-4- Hydroxymethylbenzoic acid, 2,6-cyhydroxy-4-P
-Methylbenzoylbenzoic acid%2s 4#6)
Lichtroxy 3-methyl-5-chlorobenzoic acid, 2
, 4.6-trihydroxy-3-acetylbenzoic acid,
2,4.6-Dolihydroxy-3-pro-5-chlorobenzoic acid, 2,6-cyhydroxy-3,5-dichloro-4-methylbenzoic acid, 2,6-cyhydroxy-3,5
-diprol-4-methoxybenzoic acid, 2,6-cyhydroxy-3-bromo-4-methoxybenzoic acid, 2,6-cyhydroxy-3-chloro-4-methylbenzoic acid, 2.
6-Sihydroxy-3-methyl-4-propionic benzoic acid, 2,6-cyhydroxy-3,5-dibromo-4-hydroxymethylbenzoic acid.

2.4.6-) Rihydroxy-3,5-dibromobenzoic acid, 2,6-cyhydroxy-3,5-short-4-
These include sodium salts, 1J tium salts, potassium salts, strontium salts, calcium salts, magnesium salts, and nitric salts of acidic coupling substances containing a carboxyl group as a substituent such as methylbenzoic acid.

Type 2: A coupling agent in which the carboxyl group of an acidic coupling substance containing a carboxyl group as a substituent is neutralized with an organic base to form a salt, i.e. a coupling agent containing a carbonyl group as a substituent as listed in Type 1. The carboxyl group of the acidic coupling substance is imidazole or benzimidazole.

2-Methyl-imidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethylimidazole, 2-propylimidacil, 2-isopropylimidazole, 2,4-dimethylimidazole, 2-phenyl-4-methyl- imidazole, 2-methyl-benray 2dazole, 2-)-nylpenzimidazole, 5,
6-dimethylimidazole, 2-methylimidacillin,
2-ethyl-4-methylimidacillin, 2-phenylimidacillin, 2-undecylimidacilline, 2-heptadecyl imidacilline, 2-isopropylimidacillin,
2,4-dimethylimidacillin, 2-phenyl-4-methylimidacillin, guanidine.

Phenylguanidine, 1,5-diphenylguanidine,
1,3-cyclohexylguanidine, 1-phenyl-3
-P-methylphenylguanidine, benzoylguanidine, biquanide, guanylurea.

Amino-1t5t5) riazine, dodecylamine, hexdecylamine, octadecylamine, dioctylamine, dioctadecylamine, icosylamine, N-methyl-N-dodecylamine, N-methyl-N
- Quaternary ammonium salts treated with organic bases such as octadecylamine, N%N-dimethyl-N-octadecylamine.

Type 3: A coupling agent in which the molecular base of a basic coupling substance containing a molecular base as a substituent is neutralized with an inorganic acid to form a salt, i.e. %2-hydroxy-3
-naphthoic acid-dimethylaminoethylamide, 2-hydroxy-3-naphthoic acid diethylaminoethylamide,
2-hydroxy-3-naphthoic acid dipropylaminopropylamide, 6-medoxy-2-hydroxy-3-naphthoic acid dipropylaminopropylamide, 2-hydroxy-3-naphthoic acid diethylaminopropylamide, 2
-hydroxy-3-naphthoic acid dimethylaminopropylamide)', 2-hy)'roxy-3-naphthoic acid morpholinopropylamide, 2-hydroxy-3-naphthoic acid morpholinoethylamide, 2-hydroxy-tonaphthoic acid dimethylaminopropylamide, 2-hydroxy-3-naphthoic acid dimethylaminopropylamide, Peridinopropylamide, 2-hydroxy-6-naphthoic acid morpholinopropylamide, 2-hydroxy-6
-Naphthoic acid dimethylaminopropylamide, 2-hydroxy-1-naphthoic acid morpholinopropylamide, 2
-Hydroxy-1-naphthoic acid-dimethylaminopropylamide, 2,6-dihydroxybenzoic acid diethylaminoethylamide, 5,5-dihydroxybenzoic acid morpholinopropylamide, 2,4-dihydroxybenzoic acid morpholinopropylamide, ortho-N- Hydrodiphenol-mono-guanidine, para-N-hydrodiphenol-biguanidine, 2,5-dimethyl-4-morpholinomethylphenol, 1-hydroxynaphthi-
The molecular base of a basic coupling substance containing a substituent K and a molecular base such as 7-7enylguanidine, 2-hydroxy-naphthyl-8-biguanidine, etc. is dissolved in hydrochloric acid, carbonic acid,
A salt that has been neutralized with an inorganic acid such as nitric acid.

Type 4: A coupling agent in which the molecular base of a basic coupling substance containing a molecular base as a substituent is neutralized with an organic acid to form a salt.

That is, the molecular base of a basic coupling substance containing a carboxyl group as a substituent specifically listed above can be substituted with citric acid, tartaric acid, gluconic acid, malic acid, glycolic acid, benzoic acid, phthalic acid, or terephthalic acid. Salts neutralized with organic acids such as succinic acid, trimellitic acid, maleic acid, oxalic acid, glutaric acid, malonic acid, succinic acid, and acidic coupling substances containing carboxyl groups as substituents specifically listed above.

Next, as the acid stabilizer used in the present invention, various known nonvolatile acids used for diazo type materials can be used. For example, citric acid, gluconic acid, oxalic acid, tartaric acid,
These include sulfamic acid, hydroxylamine hydrochloride, boric acid phosphoric acid, etc. In addition, in order to improve the storage stability of the recording material after recording, thiourea, L-ascorbic acid, and urea are used as antioxidants.

Even if allyl isothiocyanate or the like is used, the color development sensitivity and storage stability of the recording medium of the present invention will not be impaired.

The polymeric binder used in the present invention is used to improve the adhesion between the recording material and the support, the coating uniformity, or the water resistance. Even if no agent is added, the characteristics of the recording medium of the present invention will not be impaired in any way. Examples of the polymeric binder include polyvinylnarcol, hydroxyethylcellulose, polyvinyl alcohol-gum arabic, polyvinyl acetate emulsion, methylcellulose, ethylcellulose, polyvinylbutyral, polyvinyl acetate, polystyrene, nitrocellulose, and cellulose acetate.

Examples include butyrate polymers, salt-and-acetate picopolymers, polymethacrylic acid esters, and the like.

Examples of the present invention will be shown below. In addition, "part" in each example
means parts by weight.

<Example 1> 4-morpholino-2,5-dibutoxyhensendiazonium boron tetrafluoride salt +1 part, sodium 2-hydroxy-6'-naphthoate 2 parts, tartaric acid 0.5 part, polyvinyl alcohol 2 parts, A coating solution consisting of 80 parts of ethanol and 20 parts of water was applied onto commonly used white photosensitive paper using a No. 24 wire bar, and dried at 60°C to produce heat-developable diazo recording paper. . Place a transparent original in close contact with the recording paper.

A latent image was formed by exposure using a diazo copying machine manufactured by Ricoh, and the entire surface was irradiated with infrared rays for development. A copy having a high-density blue-green image was obtained. Further, even when heat was applied to the uncolored area, no bluish-green image was formed and the image was fixed.

Further, after leaving the recording base paper at 40° C. and 20% relative humidity for 3 days, a latent image is formed with light energy in the same manner as above,
When developed with thermal energy, a copy was obtained with a high density blue-green image and no fogging of the base was observed. In this way, it was possible to provide a recording paper with excellent color development sensitivity and storage stability.

<Example 2> 2 parts of 4-morpholino-2,5-diptoxybenzenediazonium chloride zinc chloride double salt, 6 parts of salt of 2,4-dihydroxybenzoic acid and guanidine, 07 parts of citric acid, 50 parts of ethanol, A coating solution consisting of 50 parts of water was applied onto precoated white high-quality paper using an air knife coater and dried at 60° C. to produce a heat-developable diazo type recording paper. The recording paper was heated at a heating temperature of 1.50° C., a heating time of 2 seconds, and a pressure of 2. After coloring was developed using a circular hot plate under the conditions of Kq/crl, the entire surface was exposed to light using a high-pressure mercury lamp, and a high-density sepia-colored circular image was obtained. Also,
As in Example 1, a recording paper with excellent storage stability could be provided.

<Example 5> 1 part of P-N,N-diethylaminobenzenediazonium boron tetrafluoride salt, 4 parts of the salt of 2-hydroxy-3-naphthoic acid morpholinopropylamide and hydrochloric acid, 90.5 parts of salt,
A coating solution consisting of 0.15 parts of thiourea, 7 parts of alcohol-soluble cellulose acetate butyrate polymer, 10 parts of butanol, and 80 parts of methanol was applied onto a polyester film using an air knife coater and dried at 60°C. This recording film was printed using a Toshiba ■ thermal printer under the conditions of applied voltage 13V and pulse width! l m 5ec
After printing with K, the entire surface was exposed to light using a Ricoh ■ diazo copier, and a clear, high-density blue image was obtained.

Also, without exposing the thermal printer after printing, 4
After leaving it at 0°C, 20°C relative humidity and 40°C, 90% relative humidity for 4 hours, the entire surface was exposed using a Ricoh diazo copier to check for discoloration, fading, and fogging. Under these conditions, no discoloration, fading, or fogging of the image was observed. As described above, it was possible to provide a placement film with excellent color development sensitivity and storage stability.

<Example 4> A coating solution obtained by kneading a mixture of 2 parts of powdered silica, 4 parts of polyurethane resin, 8 parts of methyl ethyl ketone, and 2 parts of toluene in a ball mill overnight on a polyester film (thickness 200μ) was applied to a roll coater. It was applied and dried to form a porous silica layer. On the layer, 1.5 parts of 4-morpholino-2,5-dibutoxybenzenediazonium boron tetrafluoride salt, a salt of 2-hydroxy-6-naphthoic acid dimethylamine propioamide and 3,5-dihydroxybenzoic acid 3 parts, oxalic acid 0.5 parts, thiourea 015
A coating solution consisting of 3 parts of polymethyl methacrylate, 80 parts of methyl ethyl ketone, and 20 parts of toluene was applied using a No. 24 wire paper and dried at 60° C. to prepare a heat-developable diazo type recording material.

This recording body was first printed using a Toshiba ■ thermal printer (printing conditions: applied voltage 14V, path/l/swidth 21nSec), and then xenon flash (exposure energy 900J).
), a cylinder-density reddish-purple image was formed against a pale background. In addition, after printing with a thermal printer, do not expose the entire surface to light with a xenon flasher, and leave it at 40°C with a relative humidity of 20%, and leave it at 40°C with a relative humidity of 90% for 36 hours, then expose the entire surface with a When looking at the degree of discoloration and fogging, no discoloration, fading, or capri was observed in the image under the above conditions. As described above, it was possible to provide a recording medium with excellent color development sensitivity and storage stability.

Additionally, the coupling agents used in this example are 2-hydroxy-naphthoic acid dimethylaminopropioamide, which develops a blue color, and a salt of 3,5-dihydroxybenzoic acid, which develops a red color. , the hue of this recording body is reddish-purple. In this way, in the recording medium of the present invention, a salt of a basic coupling substance and an acidic coupling substance can be used as the coupling agent.
It has the characteristic of being able to develop various colors.

Claims (1)

[Scope of Claims] (1) A recording layer containing a diazonium compound, a coupling agent obtained by neutralizing an acidic or basic coupling substance with an inorganic or organic base or acid, and an acid stabilizer on a support. A record body characterized by the following: (Recording body according to claim (1), which uses an acidic coupling substance containing a carboxyl group as the 21 substituent. (3) Uses a basic coupling substance containing a molecular base as a substituent. (4) The recording medium according to claim 11, wherein the coupling substance is an organic base or an organic base.