JPS62207672A - Photosensitive thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a photosensitive thermal recording material having high sensitivity and excellent raw preservability, by incorporating a polybasic acid having a primary dessociation constant in a specified range into an undercoat layer. CONSTITUTION:A polybasic acid having a pirmary dessociation constant of 10<-1>-10<-3> is incorporated into an undercoat layer, in a photosensitive thermal recording material comprising the undercoat layer between a base and a photosensitive thermal recoding layer which comprises as main constituents a diazoium salt, a coupler compound and a color developer consisting of a particulate dispersed material of a hydrophobic organic basic compound giving a basic atmosphere on being melted by heating. The polybasic acid may be, for example, citric acid, tartaric acid or dihydroxytartaric acid. Where the pH of the recording layer tends to be gradually increased due to partial melting of the particulate dispersed material of the organic basic compound during raw preservation of the recording material under hot and humid conditions, a buffer effect of the polybasic acid in the undercoat layer prevents the pH from being increased, and accordingly, the raw preservability of the recording material is enhanced.

Description

[Detailed Description of the Invention] Technical Field of the Invention The present invention relates to a photosensitive and thermosensitive recording medium, and more specifically, it has excellent storage stability (hereinafter referred to as raw storage stability) before photodecomposing a diazonium salt, and This invention relates to a light and heat sensitive recording material that develops color with high sensitivity when heated.

) Prior art and its problems Conventionally, when forming an image using a light and heat sensitive recording medium, 2
One is to expose the light and heat sensitive recording material to an image using a fluorescent lamp or a mercury lamp, as with general diazo copying materials, and then to infrared rays, a heat roller, high frequency, etc.
The other method is to heat the photosensitive and thermosensitive recording material to about 200°C.
The unreacted diazonium salt in the non-image area is decomposed by heating the image to the above temperature using a thermal head or the like, and then irradiating the entire surface with ultraviolet rays using a fluorescent lamp or mercury lamp as with general diazo copying materials. This is a way to establish it.

For uses similar to diazo copying materials, such as the former,
For light and heat sensitive recording materials that require a high development temperature of 150°C to 200°C during heat development, it is necessary to use a diazonium salt with high heat resistance, which is disadvantageous for forming high-density images. Therefore, there is a need for a highly sensitive light- and heat-sensitive recording material that can obtain sufficiently high color density at a low temperature of 50 DEG C. to 150 DEG C.

In addition, in recent years, high-speed thermal printing has been required in the field of thermal printers and facsimiles, especially in applications similar to general thermal recording materials, such as the latter. It is requested. However, in general, there is a contradictory relationship between increasing the sensitivity of heat color development and raw shelf life. This tends to lead to lower sensitivity of color development.

The present inventors conducted research with the intention of providing a photosensitive and thermosensitive recording material that solved this problem, and first used a guanidine derivative having a specific general formula as a basic substance that promotes the reaction between a diazonium salt and a coupler compound. We have already discovered and proposed a scale that provides a light and heat sensitive recording material with high sensitivity and excellent storage stability. (Unexamined Japanese Patent Publication No. 57-45094
, 57-125091) However, in recent years, even in such light and heat sensitive recording materials, there has been an increasing demand for higher heat color development sensitivity, and if higher sensitivity is not achieved, there is a tendency for deterioration of raw shelf life. However, there was a need for technology to further improve shelf life.

(C) Object of the Invention An object of the present invention is to overcome these drawbacks and provide a photosensitive and thermosensitive recording medium with high sensitivity and excellent shelf life.

ρ) Structure and operation of the invention The present invention provides a photosensitive material whose main components are a diazonium salt, a coupler compound, and a fine-particle dispersion of a hydrophobic organic basic compound that is melted by heat and exhibits a basic atmosphere as a color developer. A light and heat sensitive recording material comprising an undercoat layer provided between a heat sensitive layer and a support, characterized in that the undercoat layer contains #lt-polybasic with a first order dissociation constant of 1010. Regarding.

Specific examples of the polybasic acid according to the present invention include citric acid, filite, malonic acid, maleic acid, citric acid, phthalic acid, and dioxytartaric acid. The reason for the effect of improving shelf life without reducing color development sensitivity is not clear, but when the organic basic compound is melted by heat and the pH of the photosensitive/thermosensitive layer increases, the color development sensitivity is reduced. Since the acid is present in the undercoat layer, it is difficult to cause a decrease in color development sensitivity, and on the contrary, during raw storage under high temperature and high humidity, part of the fine particle dispersion of the organic basic compound dissolves and the coating layer of the photosensitive and thermosensitive layer deteriorates. When the pH of the coating tends to gradually increase, it is thought that the buffering effect of the polybasic acid in the undercoat layer suppresses the increase in pH of the coating layer, thereby improving the shelf life.

These acid compounds are preferably used in a weight ratio of 1.0% to 30%, more preferably 5 to 15%, relative to the organic basic compound.

If the amount of the acid compound added is less than the above-mentioned preferred range, the effect of improving raw storage stability will be weak, and if it is too much, it will cause a decrease in color development sensitivity. Further, in the undercoat layer, binders and pigments that are commonly used in the field of thermal paper can be suitably used. This is also observed when using as a color developer, but when used in combination with guanidine derivatives of the following general formulas (I) and (II) as particularly preferred organic basic compounds, it is possible to achieve high sensitivity and long shelf life. An excellent light and heat sensitive recording medium can be obtained.

General formula (I) R+5 General formula (n) 几6 [In the formula, R1, R2, R5, R4 and R5 are hydrogen, alkyl having 18 or less carbon atoms, cyclic alkyl, aryl, aralkyl, amino, alkylamino, acylamino, carbamoyl represents an amino or heterocyclic residue, R16 is lower alkylene, phenylene, naphthylene or hecoto
The aryl group in the formula includes lower alkyl, alkoxy, nitro, acylamino, alkylamino, and halogen/substituent groups. ] As the diazonium salt used in the present invention, any compound used in conventionally known diazo type copying materials can be used, but for example, the following compounds can be particularly preferably used.

Specific examples include 4-N,N-dimethylaminobenzenediazonium chloride, a-pcol-4-N,N-dimethylamino/benzenediazonium chloride, 4-N,N-
Diethylaminobenzenediazonium chloride, 2,5
-jethoxy-4-N, N-diethylaminobenzenediazonium chloride, 4-N-ethyl-N-hydroxyethylaminobenzenediazonium chloride, 4-N,
N-jethoxyaminobenzenediazonium chloride,
4-phenylaminobenzenediazonium chloride, 4
-N-(P-methoxyphenyl)-aminobenzenediazonium chloride, 4-morpholinobenzenediazonium chloride, 2,5-jethoxy-4-morpholinobenzenediazonium chloride, 4-oxacyridinobenzenediazonium chloride, 3-methyl- 4-piperidinobenzenediazonium chloride, 4-ethylcapto-2,5-jethoxybenzenediazonium chloride,
4-Tolylmercapto-2,5-jethoxybenzenediazonium chloride, 4-benzylmercapto-2,5
- Dimethoxybenzenediazonium chloride, etc.

Further, as the coupler compound which reacts with the diazonium salt to form an azo dye, any compound capable of coupling with the above-mentioned diazonium salt can be used. Examples of these cabler compounds include phenol derivatives and oxynaphthalene derivatives, and compounds containing active methylene groups include the following compounds.

(1) Phenol derivative pyrocatechol resorcin phloroglycine pyrogallol meta-aminophenol para-aminophenol diethylaminophenol N-lauryl-para-aminophenol N-acyl-meta-aminophenol 3.3', 5-1 lyhydroxydiphenyl 3.3',
5.5'-Tetrahydroxydiphenyl alpha-resorcinic acid beta-resorcinic acid gamma-resorcinic acid phloroglucinic acid gallic acid diresorcinyl sulfide diresorcinulphoxide 3.5-resorcinic acid ethanolamide 2.4-resorcinic acid ethanol Amide 4-Bromresorcin 4-Chlororesorcin 2-Methylresorcin 3. 3'-Butylenedioxydiphenol 3. 3'-Ethylenedioxydiphenol Bisphenol A) Oxynaphthalene derivative 2.3-Dihydroxynaphthalene β-naphthol α -Naphthol 1.6-dihydroxynaphthalene 2.3-dihydroxyna7talene 6-sulfonic acid 2-
Naphthol-3,6-disulfonic acid 1,8-dihydroxynaphthalene-8-sulfonic acid 2-hydroxy-3-naphthoic acid 1-N-β-hydroxyethyl-amide 2-hydroxy-3-naphthoic acid-N,N-bis β-Hydroxyethylamide 5-(paranitro)-benzamide-1-naphthol 1
-Naphthol-3-(N-β-hydroxyethyl)-sulfone-amide 2-hydroxy-3-propylmorpholinonaphthoic acid 2
-Hydroxy-3-naphthoic acid-0-toluicide 2-hydroxy-3-naphthoic acid molelinoglopyramide 2-hydroxy-3-naphthoic acid-4'-chloroanilide 2-hydroxy-3-naphthoic acid-57-chloro-
2/.

4'-di-methoxyanilide 2-hydroxy-3-naphthoic acid-27,5/-dimethoxyanilide 2-hydroxy-3-naphthoic acid-2'-ethoxyanilide 2-hydroxy-3-naphthoic acid-2'-methoxy Anilide 2-hydroxy-3-naphthoic acid phenyl ester 2
-Hydroxy-3-naphthoic acid-4'-phenoxyanilide 2-hydroxy-3-naphthoic acid-47-pendeloxyanilide 2-hydroxy-3-naphthoic acid + 47-funinethyloxyanilide 2-hydroxy-3-sugar 7toic acid-2'-pendeloxyanilide 2-hydroxy-3-naphthoic acid-27-dimethylanilide 2-hydroxy-3-naphthoic acid-4'-methoxyanilide (3) Compound containing active methylene group 1-phenyl -3-Methyl-pyrazolone (5) Acetoacetic acid anilide 1-phenyl-3-carboxypyrazolone Acetoacetic acid Cyclohexylamide Acetoacetic acid Benzylamide Cyanoacetanilide Cyanoacetomorpholine 4-Carboxy-acetoacetanilide These The coupler compound can be contained in the light and heat sensitive layer as a fine particle dispersion with a particle size of 10 μm or less using a dispersion means such as a ball mill, sand grinder, attritor, etc.

Further, one kind or a combination of two or more kinds of coupler compounds may be used to produce a dye exhibiting desired spectral absorption characteristics.

In addition, during dispersion, the coupler compound may be dispersed alone, but it may also be co-dispersed with an organic basic compound and other additives if necessary.

If the organic basic compound used as a color developer is soluble in the water used as a solvent for the coating solution when applied to the support, the pH of the coating solution will increase, causing capri of the background and deterioration of storage stability. Therefore, it is desirable to exist as a discontinuous fine particle dispersion in the coating layer, and the solubility in water at 20°C is 1. If OF/ is the following, it will have good humidity and heat storage stability, and heterocyclic compounds such as aliphatic amines, pyrrolidine visiting conductors, imidazole derivatives, imidacillin derivatives, piperidine derivatives, etc. can also be suitably used, but in particular, the following general formula (I)
When the hydrophobic guanidine derivative tS is used as a coloring agent, it is possible to obtain a diazo-fixed heat-sensitive recording material which has excellent storage stability under high temperature and high humidity conditions, and which develops color with high sensitivity and has excellent image storage stability. I can do it. Also, the color developer has a melting point of 10
Those having a temperature in the range of 0 to 170°C can be particularly preferably used.

The color developer may be dispersed alone using a dispersion means such as a ball mill, a sand grinder, an attritor, etc., but it may also be co-dispersed with a coupler compound and other additives as necessary.

If necessary, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, sodium alginate, etc. can be added as a protective colloid agent in an amount of 0.5 to 10% of the solid content during dispersion.

or [wherein R, 1, "2", "5-R4 and R5 are hydrogen, alkyl having 18 or less carbon atoms, cyclic alkyl, aryl, aralkyl, amino, alkylamino, acylamino, carbamoylamino, heterocyclic residue represents lower alkylene, phenylene, naphthylene or 802, S2
, S, 0, -NH- or -represents a double bond), and the aryl group in the formula is lower alkyl, alkyl, xy, nitro,
It also includes those having a substituent selected from acylamino, alkylamino groups, and halogen.] Typical examples thereof are shown in Table 1, but are not limited thereto. (in the table) represents cyclohexyl foundation.

Table-1 N)1 l-15 CH3 CM.

uN)iN)1N)i2-C-NH2 These guanidine derivatives shown above can be easily synthesized by a known method or a method similar thereto.

The light-sensitive and heat-sensitive layer of the present invention contains a diazonium salt, a coupler compound, a color developer, etc. as main components, and is coated on the undercoat layer with a single layer.
Alternatively, the main component may be divided into two or multiple layers and provided on the undercoat layer.

Furthermore, an acid compound or the like may be added as an anti-cipre coupling agent, if necessary.

Binder materials for forming the photosensitive and heat-sensitive layer of the present invention include corn starch, gum arabic, glue, gelatin, casein, methyl cellulose, ethyl cellulose, droxyethyl cellulose, carboxymethyl cellulose, polyacrylamide, carboxymethyl starch, and dialdehyde. Starch such as starch or its modified products and derivatives, polyvinyl alcohol or its modified products and derivatives, polyvinylpyrrolidone, imbutylene-
Maleic anhydride copolymer, polyacrylate, styrene-maleic anhydride copolymer, vinyl chloride, polyvinylidene chloride, polystyrene, styrene-styrene-butadiene rubber (=,, 5BR), methacrylate-butadiene rubber (= MBJ, nitrile butadiene rubber (=NBR
), polymethyl methacrylate, polyglobylene, polyacrylonitrile, acrylic ester, and other synthetic resin emulsion binders, and these binder materials can be used alone or in combination.

Since the coupling reaction of diazonium salts is promoted in polar solvents such as water, the storage stability of fixed heat-sensitive recording materials using diazonium salts, especially under high temperature and high humidity conditions, is limited by binder materials with low equilibrium moisture content. It is also greatly improved by selecting formalin, glyoxal,
The storage stability can also be improved by incorporating a water-proofing agent commonly used in water-soluble polymer binder materials, such as chromium alum, geltaraldehyde, melamine/formalin resin, and urea/formalin resin.

Specific examples of pigments used in the photosensitive and heat-sensitive layer of the present invention include kaolin, calcined kaolin, talc, waxite, diatomaceous earth, styrene resin particles, calcium carbonate, magnesium hydroxide, aluminum hydroxide, magnesium carbonate, Examples include titanium oxide, carbonic acid/< +7 rum% urine-formalin filler, cellulose filler, aluminum oxide, etc., but from the viewpoint of thermal head matching properties such as scum and sticking, JP 53-118059.5
4-25845%54-118846.54-1188
It is desirable to use an oil-absorbing pigment with an oil absorption of 80-500d7100f according to the measuring method specified in JIS K5101 as described in Publication No. 47, and especially in the layer that comes into direct contact with the thermal head, calcined kaolin, urea-formalin filler, etc. It is desirable to use an oil-absorbing pigment exhibiting the above-mentioned oil absorption amount.

Other auxiliary ingredients include UV inhibitors and antioxidants such as thiourea, and waxes and metal soaps may be used to improve sticking and color sensitivity. I can do it.

Specifically, waxes include paraffin wax, carnauba wax, microcrystalline wax, polyethylene wax, as well as higher fatty acid amides such as stearic acid amide, lauryl amide, myristyl amide, hardened tallow acid amide, valmitic acid amide, Examples include oleic acid amide, acetamide, coconut fatty acid amide, methylolated products of these fatty acid amides, methylene bis stearamide, ethylene bis stearamide, and higher fatty acid esters.

Examples of the metal soap include polyvalent metal salts of higher fatty acids, ie, zinc stearate, aluminum stearate, calcium stearate, zinc oleate, and the like.

Also, as a sensitizer that improves color development sensitivity, it has a melting point of 90℃~
It is also possible to use any substance that has good compatibility with organic basic compounds, coupler compounds, etc. when heated at 150°C.

Any of these substances can be used in the summer as long as they have good compatibility when heated, but in particular - benzene rings,
A substance having a naphthalene ring and also having a polar group such as an ether bond or a carbonyl group (ketone group, ester group) can be suitably used. Specific examples include dimethyl terephthalate, dibenzyl terephthalate, 1-methoxynaphthalene, 1,4-jethoxynaphthalene, and benzyl ether of P-hydroxybenzoic acid benzyl ester.

It can be used alone or dispersed, but it can also be used co-dispersed with an organic basic compound, a coupler compound, etc.

Further, a protective layer may be provided on the photosensitive and heat sensitive layer for the purpose of improving the water resistance, chemical resistance, and anti-glare properties of the image.

As the support, in addition to paper, synthetic resin films, laminated paper, etc. can also be used.

(2) Examples Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 An undercoat layer is provided on a support with the following formulation so that the coating weight after drying is 4.028.

The unit is parts by weight.

Next, a photosensitive/thermosensitive skin coating liquid is prepared with the following formulation, and applied onto the undercoat layer so that the coated amount after drying is 9.0 f/lri, and dried to prepare the entire photosensitive/thermal recording material.

Incidentally, liquids A and B were prepared by grinding the following formulations in a ball mill for 48 hours.

Solution A Example 2 Same as Example 1 except that citric acid was used instead of oxalic acid for the underfoot layer in Example 1.
A photosensitive and thermosensitive recording medium was prepared.

Example 3 A light and heat sensitive recording material was prepared in the same manner as in Example 1 except that tartaric acid was used instead of oxalic acid in the undercoat layer.

Comparative Example 1 A light and heat sensitive recording material was prepared in the same manner as in Example I except that oxalic acid was not added to the undercoat layer.

Comparative Example 2 A light and heat sensitive recording material was prepared in the same manner as in Example 1, except that the undercoat 1- was not provided and the composition of the light and heat sensitive j- was the same as in Example 1.

The light and heat sensitive recording material thus obtained was printed and recorded using a Facomfax 621C manufactured by Fujitsu, the diazonium salt was decomposed and fixed by UV exposure on the entire surface, and the color density was measured using a Macbeth densitometer (RD-514). did.

In addition, as a moisture and heat resistance test to evaluate raw storage stability, the photosensitive and thermosensitive recording material prepared as described above was left at 40°C and 90°C for 24 hours, and then the diazonium salt was photolyzed and tested in the same manner as above. The density of background fog was measured.

■ Effect of the invention A first-order dissociation constant of 10-1 to 10 is established between the support and the photosensitive/thermosensitive layer.
By containing the polybasic acid, it was possible to obtain a photosensitive and thermosensitive material with high sensitivity and excellent shelf life.

Claims (1)

[Scope of Claims] 1. A light-sensitive and heat-sensitive layer and a support comprising as main components a fine particulate dispersion of a diazonium salt, a coupler compound, and a hydrophobic organic basic compound that melts under heat and exhibits a basic atmosphere as a color developer. In a photosensitive and thermosensitive recording material provided with an undercoat layer between
A photosensitive and thermosensitive recording material containing a polybasic acid of ^-^1 to 10^-^3. 2. The photosensitive and thermosensitive recording material according to claim 1, wherein the hydrophobic organic basic compound is a hydrophobic guanidine derivative represented by the following general formula (I) or (II). General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ General formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R_1, R_2, R_3, R_4 and R_5 are hydrogen, carbon atoms with 18 or less Represents alkyl, cyclic alkyl, aryl, aralkyl, amino, alkylamino, acylamino, carbamoylamino, heterocyclic residue, R_6
represents lower alkylene, phenylene, naphthylene or ▲Mathematical formula, chemical formula, table, etc.▼ (in the formula, X represents lower alkylene, SO_2, S_2, S, O, -NH- or a single bond), The group is lower alkyl,
Also included are those having a substituent selected from alkoxy, nitro, acylamino, alkylamino groups and halogen. ]