JPH04197783A - Thermally recording diazo material - Google Patents

Abstract

PURPOSE:To obtain a thermally recording diazo material with an improved shelf life before recording process by using a specific coupling compound and 5-substitution amino-1-naphthol-2-sulfonic acid derivative as a coupling component as constituent components. CONSTITUTION:The recommended diazo compound expressed by formula I is such as having a melting point of 30 deg.C to 200 deg.C and the recommended dosage is max. 0.02 to 3g/m<2> with water solubility of 1% or lower. In addition, 5-substitution amino-1-naphthol-2-sulfonic acid derivative as a coupling component is selected from among chemical components expressed by formula II. In the formula II, R4 is a group shown by formulae III, IV. The basic materials are ammonium acetate and tricyclohexylamine, and the binders are polyvinyl alcohol and methylcellulose. The thermally recordable layer is formed by preparing an application liquid consisting of a diazo compound, a coupling component, a basic material and a binder dispersed in a solvent in a mixed state, then applying the liquid on a support and drying it.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a diazo thermosensitive recording material. For more details,
The present invention relates to a diazo thermosensitive recording material that forms a red colored image consisting of a diazo compound, a force/7 pulling component, and a base.

(Prior Art) As a recording material used in a heat-sensitive recording method, a leuco color-forming heat-sensitive recording material is usually used. In this heat-sensitive recording material, an image is formed on the recording material U by utilizing the fact that either the leuco dye or the acidic substance dispersed in the heat-sensitive recording layer becomes enemies (due to thermal energy) and causes a coloring reaction. It is something that will be done.

Since this recording material has low fixability of recorded images, it has the disadvantage that color develops in unexpected places due to harsh handling or heating after recording, which stains the recorded images.

In recent years, research on diazo coloring type heat-sensitive recording materials has been actively conducted as a heat-sensitive recording material free from such drawbacks. For example, JP-A No. 57-123086, Journal of the Image Electronics Engineers of Japan, 11.290 (1982), etc., describe a color forming component consisting of a diazo compound, a coupling component, and a basic component (including substances that become basic when heated). According to this recording material, an image is formed on the recording material by heating, and then the recording material is irradiated with light to decompose unreacted diazo compounds. Color development can be stopped (fixed) by

However, even in recording materials that use diazo compounds,
Precoupling (coloring reaction) progresses gradually during the storage stage before recording, and undesirable coloring (fogging) tends to occur.

Various improvements have been made to eliminate this coloration (capri). For example, one of the components involved in color development may be present in the form of discontinuous particles (solid dispersion), or one of the components involved in color development may be separated as a separate layer (Japanese Unexamined Patent Publication No. 123086/1986). Some measures are being taken to set up the system. This is intended to prevent contact between the components and prevent the progress of pre-coupling. However, in either case, although the storage stability (so-called raw storage stability) is improved satisfactorily, the thermal response (meltability to heat), which is one of the important performances, tends to decrease.

Furthermore, we developed a non-polar wax-like substance (Japanese Patent Laid-Open No. 57-44
141, JP-A-57-142636) or a hydrophobic polymer substance (JP-A-57-192,944) to encapsulate one of the coloring components and isolate it from the other components. Are known.

These encapsulation methods involve melting a wax-like substance or a polymeric substance in an appropriate solvent, dissolving or dispersing a coloring component in this solution, and forming a capsule by jelly-forming the capsule around the core substance. This is different from the concept of a normal capsule covered with a shell. For this reason, when a capsule is formed by dissolving a color-forming component, the color-forming component does not necessarily become the core material of the capsule, but rather mixes uniformly with the encapsulating material, and pre-coupling gradually progresses at the wall interface of the capsule. In addition, when the coloring component is dispersed to form capsules, the coloring reaction does not occur unless the walls of the capsule are melted by heat, resulting in problems such as a decrease in thermal responsiveness. Furthermore, there is a manufacturing problem in that the solvent used to dissolve the wax-like substance or polymeric substance must be removed after the capsules are formed, and this method is not completely satisfactory.

Therefore, as a method to solve these problems, at least one of the components involved in the coloring reaction is contained in a core material, and a wall is formed around this core material by polymerization to form a microcapsule. Kaisho 59-19088
6, Japanese Unexamined Patent Publication No. 60-6493), etc. have also been proposed.

By the way, in recent years, as diazo thermosensitive recording materials have come into wide use, there is a strong demand for multi-colored materials in addition to the conventionally mainstream black hue.

Many azo dyes corresponding to yellow, red, and blue colors have been known and put into practical use.

However, when used as an azo dye or pigment,
The diazonium compound or the coupling component is treated as an intermediate for obtaining the dye, respectively. In particular, diazo compounds are generally known to be unstable compounds, and are rarely handled and isolated in solution.

When used as a diazo thermosensitive recording material, the diazo compound is isolated and used, so its storage stability (raw storage)
becomes an important issue.

If the storage stability is low, the sensitivity of the diazo thermosensitive recording material will drop significantly (decomposition of the diazonium salt), and furthermore, the decomposed product of the diazonium salt will become colored over time, causing the background to fade, reducing the value of the product.

From this point of view, diazonium salts with higher storage stability were investigated, and 4-morpholino-2゜5-dibutoxyhenzendiazunium chloride l'chloride double salt, 4-morpholino-2゜5-dibutoxyhenzendiazunium chloride double salt,
Henzendiazonium salts containing an electron donating group, such as tolylthio-2,5-dibutoxyhenzendiazonium chloride zinc chloride double salt, have been discovered and put into practical use.

The inventors also disclosed that 4-substituted amino-2-alkoxyhenzendiazunium salts exhibit better storage stability. (Patent Application No. 1982-239340)
In order to obtain a specific clear hue through a coupling reaction with these specific diazonium salts, a specific camping component is essential.

In addition, recorded images are stored for a long time, but depending on how they are used, they are often placed in locations where they are constantly exposed to fluorescent lights or sunlight.

This requires strong light fastness of the image.

In order to improve the light fastness of images, it is known to coexist with anti-fading agents and ultraviolet absorbers, but the effects are not always sufficient, and there are problems caused by adding new components, such as Problems include increased fog and increased manufacturing costs.

Improvements in these respects have also been strongly desired.

(Problem B to be Solved by the Invention) The present invention provides a diazo thermosensitive recording material with pre-recording stability (
The purpose of this invention is to provide a diazo thermosensitive recording material with improved storage stability. In particular, the present invention aims to provide a diazo thermosensitive recording material exhibiting a red hue.

Furthermore, the present invention aims to provide a diazo thermosensitive recording material with improved storage stability of recorded images.

(Means for Solving the Problem) The present invention provides a diazo thermosensitive recording material having a thermosensitive recording layer containing a diazo compound, a coupling component, a base, and a binder on a support.
2-alkoxyhenzendiazunium salt and 5-substituted amino-1-naphthol-2- as a coupling component
This was achieved by a heat-sensitive recording material characterized by containing a sulfonic acid derivative.

As the diazonium compound, a compound represented by formula (1) is preferably used.

(+) R1, R2, R3 are alkyl groups that may have substituents,
It represents an aralkyl group or an aralkyl group, and R, , L, and R may each be the same or different.

However, if the number of carbon atoms in R, R, and R3 is small, water-cooling properties will occur, especially when a water-soluble binder is used. ) It may cause stains on the skin, or if you try to microcapsule it using something dissolved in an organic solvent, it may not be able to be sufficiently contained in the microcapsules, or it may come out of the microcapsules over time and cause bleed coupling. It is not desirable because In particular, red stains have high visibility, so keep them as low as possible.

In order to solve these problems, the number of carbon atoms in R, R, and R3 is preferably about 12 or more, particularly preferably 14 or more.

Substituents for R1, Rt, and R3 include alkyl groups, aryl groups, hydroxy groups, alkyloxy groups, aryoloxy groups, alkylthio groups, arylthio groups, acyl groups,
Examples include an alkoxycarbonyl group, an aralkyl group, a carbamoyl group, an asolamino group, a halogen atom, and a cyano group.

X- represents an acid anion.

The diazo compound represented by formula (1) preferably has a melting point of 30°C to 200'C, and more preferably has a melting point of 50°C to 150'C from the viewpoint of handling.

Furthermore, it is more preferable to use the diazo compound of the present invention by encapsulating it in microcapsules for the purpose of preventing ble coupling. these? It is preferable that it has an appropriate solubility in the container.

For this purpose, it is preferable to have a solubility of 5% or more.

Further, the water solubility is preferably 1% or less.

In addition, these diazo compounds are contained in the heat-sensitive recording layer in the range of 0°02 to
It is preferable to use the amount in the range of 3 g/m'', but from the viewpoint of color density, it is more preferable to use the amount in the range of 0.1 to 2 g/m''.

Specific examples are shown below, but it goes without saying that the present invention is not limited to these compounds.

OCrzHzs 0CiLOCJnO(n-CaL) 2I) OCLCON(n-Catlq) 2 The above diazo compounds according to the present invention may be used alone or in combination of two or more.

The 5-substituted amino-1-naphthol-2-sulfonic acid derivative which is the force/knobbling component used in the present invention is selected from compounds represented by the formula (ITI).

(ITI) H R,NH In the formula (ITI), R4 is a group represented by Iv or V.

(Iv) R, C- (V) R7S- And Rs and R6 represent a substituted alkyl group, a substituted aralkyl group, or a substituted aryl group. R2 and R6 may be the same or different.

Substituents further bonded to RS', R, include alkyl groups, alkoxy groups, aryl groups, cyano groups, halogen atoms, halogenated alkyl groups, alkoxycarbonyl groups,
Examples include an alkylcarbonyl group, an arylcarbonyl group, an amino group, a carbamoyl group, an acylamino group, and a sulfonyl group.

Among Rs and R-, alkyl groups having 1 to 25 carbon atoms, aryl groups having 6 to 30 carbon atoms, and aralkyl groups having 7 to 30 carbon atoms are preferably used, but alkyl groups having 6 to 30 carbon atoms, aryl groups, More preferred are 7 to 30 aralkyl groups.

Further, it is preferable that the total carbon number of R1 and R7 is 14 or more for the purpose of lowering water solubility and improving oil solubility. This is necessary for the purpose of preventing red stains, which have high visibility.

Specific examples are shown below, but the present invention is not limited to these compounds.

H CH,C0N)l C,1lh3cON11 H C-HqCHCONIl C2II 5 4) OH6)
. □ 8) (!llCH35O2
NH These coupling components may be used alone or
Moreover, two or more types can also be used in combination. These coupling components are normally used in a range of 0.05 to 5 g/m''.

The basic substance for forming the basic atmosphere used in the present invention can be arbitrarily selected from organic basic substances for -C or substances that generate alkali upon heating. Specific examples of these include ammonium acetate, tricyclohexylamine, trihensylamine, octadecylhensylamine, stearylamine,
2-benzylimidazole, 4-phenylimidazole, 2-phenyl-4-methyl-imidazole, 2-undenruimidublin, 2.4.5-) Riff True 2-
Imidacillin, 1.2-diphenyl-434-dimethyl-2-imidapurine, 2-phenyl-2-imidapurine, l,2.3-)riphenylguanidine, 1.2-ditolylguanidine, 1.2-dicyclohexyl Guanidine, 1,2゜3-tricyclohexylamine, guanidine trichloroacetate, N,N'-dihenzylpiverazine, 4,4'-dithiomorpholine, morpholinium trichloroacetate, 2-amino-hendithiazole, Examples include 2-henzoylhydrazinohenzuthiazole. These compounds may be used alone or in combination of two or more depending on the purpose.

Examples of binders used in the heat-sensitive recording layer include polyvinyl alcohol, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose, gum arabic, gelatin, polyvinylvinylidene, casein, styrene-butadiene latex, acrylonitrile-butadiene latex, and polyacetic acid. Mention may be made of vinyl, polyacrylic esters and ethylene-vinyl acetate copolymers, these compounds being used in the form of various emulsions.

The amount of binder used ranges from 0.5 to 5 g/m2 solids.

The heat-sensitive recording layer is made by attriking a diaz compound, a cambling component, a basic substance, and a binder together with a suitable solvent.
After mixing and dispersing using a sand mill or the like to prepare a coating solution, this coating solution is applied onto a support by bar coating, blade coating, air knife coating, Gravini 2 cloth, roll coating, spray coating, dip coating, etc. It can be formed by coating and drying.

Moreover, the diaz compound of the present invention can also be used in the form of microcapsules.

The method for forming microcapsules can be carried out using already known methods. It will be briefly described below.

First, the above diaz compound is dissolved or dispersed in a suitable organic solvent, and then this solution or dispersion (oil-based liquid) is emulsified and dispersed in an aqueous medium.

Examples of the solvent used include phosphoric acid esters, phthalic acid esters, carboxylic acid esters, fatty acid amides, alkylated biphenyls, alkylated terphenyls, chlorinated paraffins, alkylated naphculenes, carbonic esters, diarylethanes, and the like.

Next, a wall made of a polymer material is formed around the emulsified and dispersed oil droplets. The reactant for forming the polymeric material is added to the oily liquid and/or the aqueous medium.

The polymeric material forming the capsule wall is impermeable at room temperature and needs to become permeable when heated, and a material having a glass transition temperature of 60 to 200°C is particularly preferred. Examples thereof include polyurethane, polyurea, polyamide, polyester, urea/formaldehyde resin, melamine resin, polystyrene, styrene/methacrylate copolymer, styrene/acrylate copolymer, and mixtures thereof.

As the microcapsule forming method, interfacial polymerization method and internal polymerization method are suitable.

For details on capsule formation methods and specific examples of reactants, see U.S. Patent Sections 3.72G, 804 and 3.
．． 796. 669q. For example, when polyisocyanate is used as a capsule wall material, a polyisocyanate and a second substance (e.g., polyol, polyamine) that reacts with it to form the capsule wall are mixed into the aqueous medium or oily liquid to be encapsulated. By emulsifying and dispersing these in water and then heating them, a polymer formation reaction occurs at the oil droplet interface and a microcapsule wall is formed.

Incidentally, an auxiliary solvent having a low boiling point and strong dissolving power may be added to the oily liquid. Polyurea is produced even if the addition of the second substance is omitted.

Furthermore, when forming microcapsules, a water-soluble polymer compound can be used as a protective colloid. Examples of the water-soluble polymer compound include water-soluble anionic polymer compounds, nonionic polymer compounds, and amphoteric polymer compounds.

These water-soluble polymer compounds are contained in an amount of 0.01 to 10% by weight.
It is used as an aqueous solution.

Binding agent when forming a heat-sensitive recording layer? A substance for further improving the thermal recording density can be added to the liquid No. 8. Specifically, it has a melting point in the range of 50 to 150°C, preferably in the temperature range of 90°C to 130°C, and is selected from compounds having good compatibility with a diaz compound, a coupling component, or a basic substance. For example, fatty acid amide,
Examples include ketone compounds, ether compounds, urea compounds, and esters. These compounds are usually 1-10μm
It is used in an amount of 0.2 to 7 g/m'' solid content.

In addition, pigments such as kaolin, talc, silica, barium sulfate, titanium dioxide, aluminum hydroxide, zinc oxide, calcium carbonate, etc., and styrene beads, for the purpose of preventing sticking to heat heads and improving writing properties.
Fine particles of urea, melamine resin, etc. can be added. Similarly, metal stone M is used to prevent sticking.
You can also use The amount of these additives added is usually in the range of 0.2 to 7 g/m2.

In addition to the above additives, stabilizers such as citric acid, tartaric acid, oxalic acid, boric acid, and phosphoric acid can also be added.

The recording layer is usually provided with a solid content in the range of 25 to 25 g/m''.

The support used in the present invention can be arbitrarily selected from materials known as supports for the heat-sensitive recording layer (f), such as high-quality paper, synthetic paper, and synthetic resin film, depending on the purpose. For example, as the paper support, heat-extracted neutral paper with a pH of 6 to 9 (described in JP-A-55-14281) sized with a neutral sizing agent such as an alkyl ketene dimer (described in JP-A-55-14281) is preferable in terms of storage stability over time. Other examples include JP-A-5'
1-116687, JP-A-58-136492, JP-A-58-69091, JP-A-5865
Papers such as those described in JP-A No. 695 and JP-A-59-35985 can be used.

Examples and comparative examples of the present invention are described below. However, each of these aspects does not limit the invention. In addition, in each of the following sections, "department" means "department" unless otherwise specified.
Parts by weight.

(Example) Example 1 3.5 parts of 4-morpholino-2-octyloxyhenzendiazunium hexafluorophosphate, 6 parts of tricresyl phosphate, 5 parts of ethyl acetate, 10 parts of trimethylolpropane trimethacrylate, and bamboo shoots. 1
A core material solution was prepared by mixing and dissolving 18 parts of -D-11ON (manufactured by Drinking Yakuhin Kogyo Co., Ltd.).

This solution was added to 65 parts of polyvinyl alcohol aqueous solution (8% by weight solution) and emulsified and dispersed at 20°C, with an average particle size of 2.
A μm emulsion was obtained. This emulsion was reacted at 60'C for 2 hours to obtain a microcapsule liquid.

(ii) 56 parts of triphenylguanidine was added to 130 parts of a polyvinyl alcohol aqueous solution (6% by weight) and dispersed using Dynomil (manufactured by V. Hacofen AG) to obtain a basic substance dispersion with an average particle size of 3 μm. was prepared.

(iii) 56 parts of 5-acetylamino-2-dioctylaminosulfonyl-1-naphthol was added to 138 parts of an aqueous polyvinyl alcohol solution (4% by weight solution) and dispersed using a Dynomill (manufactured by Vuillier Hakofen AG), A coupling component dispersion having an average particle diameter of 3 μm was prepared.

(iν) 10 parts of microcapsule liquid, basic substance N
'1. 5 parts of the liquid, 6.7 parts of the coupling component dispersion, and 15 parts of the calcium carbonate dispersion (40% by weight liquid) were mixed to prepare a coating liquid.

(v) A heat-sensitive recording sheet having a heat-sensitive recording layer having a dry weight of 10 parts/m2 by applying this coating solution onto the surface of smooth high-quality paper (50 parts/m2) and drying it at a temperature of 40°C for 30 minutes. was created.

Example 2 5-methanesulfonylamino- as a coupling component
A heat-sensitive recording sheet was prepared in the same manner as in Example 1 except that 2-dioctylaminosulfonyl-1-naphthol was used.

Example 3 A heat-sensitive recording sheet was produced in the same manner as in Example 1 except that the compound shown in Specific Example 5 was used as the diaz compound.

Comparative Example 1 A heat-sensitive recording sheet was obtained in the same manner as in Example 1 except that 5-methylsulfonyl-2-dimethylaminosulfonyl-1-naphthol was used as the force and bling component, but the red stain (fog) on the background was high. Ta.

Comparative Example 2 A heat-sensitive recording sheet was produced in the same manner as in Example 1, except that 1-phenyl-5-pyrazolone-3-carboxylic acid octylamide was used as the coupling component.

Comparative Example 3 A thermophilic recording sheet was obtained in the same manner as in Example 1 except that 1,3-dihexylbarbituric acid was used as the coupling component.

Next, a color development test using a hot plate of the obtained thermosensitive recording sheet and a comparison test of the storage stability of the obtained image and the background part were conducted.

In the preservability comparison test, a comparison was made based on the difference in Z color density between those irradiated with fluorescent light at 32,000 lux for 16 hours and those that were not irradiated with light.

Changes in color density are caused by Machhess reflex and shock (McHess Co., Ltd.)
(manufactured by).

The results obtained are shown in Table 1.

Table 1 As is clear from Table 1, the diazo heat-sensitive recording material containing the diazo compound and the coupling component according to the present invention develops a clear red hue, has little staining on the background, and has a good image quality. It is clear that the storage property is excellent.

Claims (1)

[Claims] (1) In a diazo thermosensitive recording material having a thermosensitive recording layer containing a diazo compound, a coupling component, a base, and a binder on a support, the diazo compound is 4-substituted amino-2-
an alkoxybenzenediazonium salt, and the coupling component is 5-substituted amino-1-naphthol-2
- A diazo thermosensitive recording material characterized by being a sulfonic acid derivative.