JPS58131093A - Thermally developable diazo-type recording medium - Google Patents

Abstract

PURPOSE:To provide the titled recording medium excellent in preservation stability and favorable in sensitivity of heat-sensitive color-producting property, by incorporating a diazo compound, an acidic coupler containing a carboxyl group in a substituent group and an alkali (alkaline earth) metal salt as a color- producing adjuvant into a recording layer. CONSTITUTION:The thermally developable diazo-type recording medium is produced by providing the recording layer on a substrate, wherein the recording layer comprises a diazo compound (A) (e.g., a double salt of P-N, N-diethylaminobenzenediazonium chloride and zinc chloride), an acidic coupler containing a carboxyl group in a substituent group (B) (e.g., 2,3-hydroxybenzoic acid), an inorganic or organic salt of an alkali (alkaline earth) metal (e.g., NaCl) as a color-producing adjuvant (C) and an acid stabilizer (D) (e.g., tartaric acid). Unlike conventional recording media of a similar type, said recording medium does not contain any color-producing adhuvant that generates an alkali, and the recording layer is maintained in an acidic atmosphere by the acidic coupler and the acid stabilizer. Accordingly, said recording medium is excellent in preservation stability and favorable in sensitivity of heat-sensitive color-producing property.

Description

[Detailed description of the invention] The present invention is a fixing process (processing in which uncolored areas do not develop color due to heat).
The present invention relates to a heat-sensitive recording material using a heat-developable diazo-type recording material.

1 Conventionally, image recording methods for converting information into visible images include:
Many things are known. Generally, scars are formed by causing physical or chemical changes in response to energy such as light, radiation, electrolysis, magnetism, heat, or pressure.

For example, there are two types of recording methods that use heat: one type that forms scratches by using physical changes such as melting, sublimation, and volatilization, and the other type that uses color development due to chemical changes caused by heat. . However, since such a heat-sensitive recording medium is configured to obtain a recording effect by heat, it has the ability to develop color even in the non-image area when heat is applied later. For that reason,
It has a defect due to the structure of the heat-sensitive recording material in that if it is mistakenly brought close to a heat source, it will develop color and lose its ability as a recording material. Therefore, improvements in this respect are desired in the general market.

Therefore, in recent years, heat-transforming diazo-type recording materials, which are dry imaging systems, have attracted attention as heat-sensitive recording materials and are being developed for practical use.

Heat-formable diazo-type recording materials are produced by using thermal energy to cause chemical changes such as decomposition and melting of the coloring agent, placing the recording layer in an alkaline atmosphere, causing azo coupling, and forming an image. A common method is to use light energy to eliminate the thermal coloring ability of the non-image area and fix the color. Although many patents have been issued using this method, at present no heat-developable diazo type recording material has been produced that satisfies storage stability and color development sensitivity.

For example, a conventionally known heat-developable diazo type recording material is composed of the basic elements of a diazo compound, a coupling agent, an acid stabilizer, and a heat developer serving as an alkali source on a support. heat-
Recording materials that use base generators such as urea derivatives and guanidine derivatives that generate water-soluble ammonia, salts of organic amines and weak acids, and organic and inorganic ammonium salts have poor color development sensitivity and storage. There are practical difficulties in terms of stability and water resistance. Furthermore, recording materials using a base generator of a salt of a water-insoluble higher aliphatic amine and a polybasic acid as a desired coloring agent have good storage stability, but have problems in terms of color development sensitivity. In addition, recording materials using water-soluble salts such as halogenated acetates with a high thermal decomposition rate, such as lower aliphatic amine salts of trichloroacetic acid, as coloring agents exhibit good coloring sensitivity, but pre-coupling It causes a ring phenomenon and has poor storage stability. That is, in the heat-developable diazo type recording material,
Those using water-soluble substances as thermal color developers have satisfactory color development sensitivity but poor storage stability, while those using water-insoluble substances have excellent storage stability but have poor color development sensitivity. Both have their advantages and disadvantages.

In view of the current situation, the present inventors conducted extensive research on heat-developable diazo-type recording compositions that have excellent storage stability and good heat-sensitive color development sensitivity, and found that they use a color development aid that generates alkali when heated. Therefore, a diazo compound and a physical coupling agent containing a carboxyl group as a substituent can undergo azo coupling under heat in an acidic atmosphere. It was discovered that these dyes react to form an azo dye, and this led to the completion of the present invention. That is, the heat-developable diazo type recording material of the present invention contains a diazo compound on a support, an acidic coupling agent containing a carboxyl group as a substituent, an inorganic or organic salt of an alkali metal or an alkaline earth metal as a coloring aid, and It consists of a recording layer containing an acid stabilizer as a basic coloring component. However, the color development aid in the present invention is an acidic substance even if it is not a neutral salt as long as it is an alkali metal or a salt containing an alkali metal (it does not affect the color development sensitivity in any way. Alternatively, some organic salts of alkaline earth metals also contain polymeric compounds.

The heat-developable diazo type recording material of the present invention not only exhibits unprecedented storage stability (it is also a recording material with good color development sensitivity).

The reason why the above physical properties were achieved is that the composition for the recording layer of the heat-developable diazo recording material of the present invention is extremely stable, unaffected by outside air (humidity and temperature) at room temperature, and does not cause the precoupling phenomenon. First, it has excellent storage stability. This is because the composition for the recording layer of the recording medium does not contain a coloring aid that generates alkali, and the recording layer is made into an acidic atmosphere by using an acidic coupling agent and an acid stabilizer. It is for this purpose. Furthermore, the color development aid used in the present invention is an inorganic salt or an organic salt of an alkali metal or an alkaline earth metal, which is a neutral salt or an acidic salt, and does not generate alkali by heat. Furthermore, the reason for the high thermal color development sensitivity of the recording medium is difficult to theoretically analyze and has not yet been elucidated; This is because the inorganic or organic salts of alkali metals or alkaline earth metals that are coloring aids interact, and the acidic coupling agent containing a carboxyl group as a substituent is converted into a coupling agent with coupling activity. It is estimated that there is. This phenomenon, that is, the coupling activation phenomenon of the skeleton coupling agent due to the interaction between the coupling agent and the inorganic salt or organic salt of the alkali metal or alkaline earth metal when heated, This is supported by the fact that this does not apply to coupling agents other than coupling agents.

As described above, the heat-developable diazo type recording material according to 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 various applications. For example, it is a particularly effective recorder for combination printers and data communication terminals, as well as for tickets, cards, and sticker-less commuter passes that require counterfeit prevention.

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, various phenylene diamine N-N-substituted compounds (4-diazo-N-N-diethylaniline etc.), aminohydroquinone ether type (
4-Diazo-2-5-diphthoxy-N-N-diethylaniline, 4-diazo-2-chloro-5methoxy-N-
benzoylaniline etc), aminodiphenyl, aminodiphenylamine and similar compounds (4-diazo-2-
5-4'-)liexydiphenylamine, etc.)
, a derivative of heterocyclic amine (4-diazo-2
-5-Schiff)xy-N-phenylmorpholine etc.
) etc. The diazo compounds described above are used as diazonium salts, which are relatively stable as sulfate or hydrochloride salts, or as double salts with zinc chloride or the like. Further, stabilization methods such as diazonium sulfonate and diazonium borofluoride can also be used.

Furthermore, various known acidic coupling agents having a carboxyl group as a substituent can be used in the present invention. For example, 2-hydroxy-6"-naphthocarboxylic acid, 2-hydroxy-3-naphtho-4L acid, 2-hydroxy-1-naphthoacid, 2,6-dihydroxybenzoic acid,
3,5-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,4.6-trihydroxybenzoic acid, 2,
6-cyhydroxy-3-methylbenzoic acid, 2,6-cyhydroxy-4-propylbenzoic acid, 2,6-cyhydroxy-4-benzylbenzoic acid, 2,6-dihydroxy, droxy-
4-bromobenzoic acid, 2,6-cyhydroxy-4-chromobenzoic acid, 2,6-cyhydroxy-4-w-dobenzoic acid, 2,6-cyhydroxy-3,5-dibromobenzoic acid, 2,6-cyhydroxy-3. 5-dibromobenzoic acid,
2,6-cyhydroxy-3-ethyl-5-bromobenzoic acid, 2,6-cyhydroxy-3-benzyl-5-bromobenzoic acid, 2,6-cyhydroxy-3-(2-carboxylethyl)-benzoic acid, 2,6-cyhydroxy-3-benzyl-5-bromobenzoic acid 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
-Syhydroxy-4-P-methylbenzoyl benzoyl fl
, 2+4+6-dolihydroxy-3-methyl-5-chlorobenzoic acid, 2,4.6-)dihydroxy-3-acetylbenzoic acid, 2,4.6-)dihydroxy-3-pro-5-chlorobenzoic acid , 2.6-cyhydroxy3.
5-dichloro-4-methylbenzoic acid, 2,6-cyhydroxy-3,5-dipro-4-methoxybenzoic acid, 2,
6-cyhydroxy-3-bromo-4-methoxybenzoic acid, 2,6-cyhydroxy-3-chloro-4-methylbenzoic acid, 2,6-cyhydroxy-3-methyl-4-propionic benzoic acid, 2,6-cyhydroxy-3, 5-dibromo-4-hydroxymethylbenzoic acid, 2,4.6-
) Rihydroxy-3,5-dibromobenzoic acid, 2. Kudzu
Dihydroxy-3,5-di-l-do-4-methylbenzoic acid and the like.

Moreover, various existing compounds can be used as the coloring aid used in the present invention, that is, an inorganic salt or an organic salt of an alkali metal or alkaline earth metal. Specific examples of such compounds are as follows. However, the compounds are not limited to those listed above, and any inorganic or organic salts of alkali metals or alkaline earth metals can be used.

l) Alkali metal salts or alkaline earth metal salts of inorganic acids, such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, etc.) I) Lamb salts, potassium salts, lithium salts, strontium salts, calcium acids, barium salts, magnesium salts 2) Alkali metal salts or alkaline earth metal salts of aliphatic monocarboxylic acids Sodium salts, potassium salts, stium salts, stonetium salts of trichloroacetic acid, palmitic acid, lauric acid, myrstic acid, stearic acid, oleic acid, lylunic acid, etc. salts, calcium salts, barium salts, magnesium salts 3) Alkali metal salts or alkaline earth metal salts of II-group polyvalent carboxylic acids - sodium salts of qvyyic acid, oxalic acid, ylutaric acid, malonic acid, succinic acid, etc. , potassium salt, lithium salt, strontium salt, calcium salt, barium salt, magnesium salt 4) Alkali metal salt or alkaline earth metal salt of aliphatic oxycarmenic acid citric acid, tartaric acid, gluconic acid, malic acid, glycolic acid Sodium salts, potassium salts, lithium salts, strontium salts, calcium salts, barium salts, magnesium salts, etc. 5) Alkali metal salts or alkaline earth metal salts of aromatic carboxylic acids, benzoic acid, phthalic acid, terephthalic acid, trimellitic acid ,
Sodium salts, potassium salts, lithium salts, strontium salts, calcium salts, barium salts, magnesilla A [6] Alkali metal salts or alkaline earth metal salts of polymeric carboxylic acids Styrene-maleic acid copolymer, isobutylene-maleic acid, etc. Acid copolymer! These include sodium salts, potassium salts, lithium salts, strontium salts, calcium salts, barium salts, magnesium salts, etc. of leic acid-itacon II copolymer.

Next, as the acid stabilizer used in the present invention, various known non-volatile acids used in diazo type materials can be used. For example, citric acid, gluconic acid, oxalic acid, tartaric acid,
These include sulfamic acid, hydroxylamine hydrochloride, boric acid, and phosphoric acid. Furthermore, in order to improve the storage stability of the inorganic material after writing, thiourea, L-ascorbic acid, urea, allyl isothiocyanate, etc. may be used as antioxidants to improve the color development sensitivity and the inorganic material of the present invention. It does not impair storage stability.

The polymer binder used in the present invention is used to improve the adhesion between the distribution material and the support, coating uniformity, or water resistance. Even if no agent is added, the characteristics of the sickle body of the present invention will not be impaired in any way. Examples of polymer binders include polyvinyl alcohol, hydroquine ethyl cellulose, polyvinyl alcohol-gum arabic, polyvinyl acetate emulsion, methyl cellulose, ethyl cellulose, polyvinyl butyral, polyvinyl acetate, polystyrene, nitrocellulose, cellulose acetate butyrate. Can you name the polymer salt vinegar picopolymer?

Next, a known method can be used to coat the recording layer on the support in the present invention.

Specifically, diazo compounds, acidic coupling agents containing carboxyl groups as substituents, inorganic or organic salts of alkali metals or alkaline earth metals, acid stabilizers, antioxidants, and polymer binders as necessary. A coating liquid in which a recording agent consisting of a recording agent is dissolved or uniformly dispersed in water or an organic solvent is applied onto a support such as paper, glass, or film using a wire bar, and then dried at a low temperature. Diazo-type recording bodies can be manufactured. However, taking into account the stability of the coating liquid, it is more practical to use a two-liquid type and have a two-layer structure for the recording layer. In such a coating method, first, an acidic coupling agent containing a carboxyl group as a substituent and a polymeric binder are dissolved in an appropriate solvent and the coating solution is coated with a wire bar, etc. dry. Next, a recording agent consisting of a diazo compound, an inorganic salt or organic salt of an alkali metal or alkaline earth metal, an acid stabilizer, an antioxidant, and if necessary a polymeric binder is applied on the layer in an appropriate solvent. A method for manufacturing a heat-transformed diazo type recording medium is to apply a dissolved coating liquid using a wire bar or the like and dry it at a low temperature.

The method for recording the heat-induced diazo type recording medium thus obtained is as follows:
A thermal head, thermal pen, infrared rays, laser light, etc. can be used as a heat source. A mercury lamp, a tungsten lamp, a xenon flood 1, a laser, or the like is used as a light source that generates ultraviolet rays used for fixing. These heat sources and light sources can be used to develop and fix the heat-developable diazo type recording material.

Examples of the present invention will be shown below.

Example 1 Part A 2.3-dihydroxybenzoic acid 2f Salt vinegar Picopolymer 3g Methyl ethyl ketone/toluene (8:2) 100-B liquid Tartaric acid
1g sodium chloride o,
Coating solution consisting of sg polyvinyl alcohol 2f water/ethanol (8:2) 100 sdA solution was applied onto pre-coated white high quality paper.
It was applied using a No. 8 wire bar and dried. A coating solution consisting of KB solution was applied onto the layer using a No. 24 wire bar, and dried at 60° C. to produce heat-developable diazo-type brass paper. Heat this recording paper with a circular heating plate at a temperature of 150℃ and pressurize it 2.
The color of the chicken was developed under conditions of heating time of 2 seconds. Next, when the entire surface was exposed with a mercury lamp, a clear, dark blue-purple color was obtained. Furthermore, even when heat was applied to the uncolored areas, no bluish-purple particles were formed, making it possible to apply a permanent image.

In addition, after coloring the brass paper with a circular heating plate, the whole surface was left at 40℃ and 20% relative humidity for 4 days without being exposed to light using a mercury lamp. Fading and θ
When checking the condition of the capri, no discoloration, fading, or capri was observed under the above conditions. In this way, the recording paper was able to provide a recording medium with excellent color development sensitivity and storage stability.

Example 2 Part A 2-Hydroxy-3-naphthoL acid 20g Ethanol 500 - Part B P-N-N-Jura'/L'7 Minohyakutsumu Shifui! #l
Potassium oxalate
log thiourine $1.
A coating solution consisting of 5f water/ethanol (1:l) 1000 A-resistant solution was applied to a commonly used white photosensitive paper using an air knife coater and dried. A coating liquid consisting of liquid B was applied onto the layer using an air knife coater and dried at 60°C to produce a heat-developable diazo type recording paper. A transparent original was closely placed over Record 1- of the recording paper and exposed to light using a diazo copying machine manufactured by Ricoh Co., Ltd. to form latent scratches. Next, when it was brought into contact with a heated roller at 150° C., a dark blue color with a high density was obtained.

Further, as in Example 1), a recording paper with excellent storage stability could be provided.

Example 3 Solution A 2.6-Sihydroquine-3-propylbenzoic acid 2g Polyvinylbutiwool 2g Ethanol
100 resistant B liquid 4-holder Orino 2,5-jigutoki one 34t4riT
l=liummumumandandashu lgcitric acid
0.5g thiourea
0.1F styrene! Leic acid copolymer potassium 4 3f water/ethanol (1:1
) 2g of powdered silica, 4g of polyurethane resin, 8g of methyl ethyl ketone, 2g of toluene on a 100-resistant polyethylene terephthalate film (thickness 700μ)
A coating solution obtained by uniformly kneading a mixed solution consisting of g in a disperser was applied using a No. 36 wire bar, and dried to form a 7-reel layer having a porous structure. A coating liquid consisting of liquid A was applied onto the layer using a No. 14 wire bar and dried. Next, a coating solution consisting of KB solution was applied onto the layer using a No. 20 wire bar, and dried at 60° C. to produce a heat-developable diazo type recording material. The recording medium was printed using a thermal printer manufactured by Nishiba Corporation (printing conditions were applied voltage 14 V, pulse width 2 m sec).
) After printing with a xenon flange, a clear high-density blue color was obtained by exposing the entire surface to xenon flange at 40℃, relative humidity 20%, and After leaving it at 40℃ and 90% relative humidity for 48 hours, the entire surface was irradiated with a xenon flasher, causing only one discoloration.
When examining the degree of discoloration and capri, no discoloration, discoloration, or capri was observed under the above conditions.

As described above, it was possible to provide a recording medium with excellent color development sensitivity and storage stability.

patent applicant Toppan Printing Co., Ltd.

Claims (1)

[Claims] (1) A bone marking layer containing a diazonium compound, an acidic coupling agent containing a carboxyl group as a substituent, an inorganic salt or an organic salt of an alkali metal or alkaline earth metal as a coloring aid, and an acid stabilizer on a support. A heat-generating diazo-type memorial resting feature.