JPS62207673A - Diazo fixation type thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a diazo fixation type thermal recording medium having excellent chemical resistance, favorable raw preservability and high sensitivity, by providing on a photosensitive thermal recording layer a protective layer comprising a highly saponified polyvinyl alcohol having a saponification degree of at least a specified percent and a nonionic surfactant having an HLB of not less than a specified value. CONSTITUTION:A nonionic surfactant having a hydrophilic-lipophilic balance (HLB) of not less than 10 is incorporated particularly in an amount of 3-0.1wt% based on the amount of a highly saponified polyvinyl alcohol having a saponification degree of not less than 95%. With the nonionic surfactant used, a uniform coated layer can be obtained, and even when a solid black image is formed, the density of the image is uniform, resolution is excellent, and an extremely favorable image can be obtained. If a so-called partially saponified polyvinyl alcohol having a saponification degree of less than 95% is used in a protective layer, raw preservability is degraded although chemical resistance is surely enhanced by the protective layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diazo-fixed heat-sensitive recording material, and more particularly to a highly sensitive diazo-fixed heat-sensitive recording material that has excellent chemical resistance and good storage stability.

In recent years, high-speed printers, facsimile machines, etc. have made remarkable progress in response to society's demand for outputting large amounts of F1V information as notebook copies as quickly as possible. 2. Description of the Related Art Electrophotography, electrostatic recording, discharge recording, inkjet recording, thermosensitive recording, and the like are known as methods for forming images on recording media according to electrical information, such as in high-speed printers and facsimile machines. Among these methods, the thermal recording method has become rapidly popular in recent years because the equipment is relatively simple and the recording paper is also relatively cheap. Regarding a heat-sensitive recording sheet formed by combining a color-forming substance such as 1FF and a phenolic compound such as bisphenol A, for example, Japanese Patent Publication No. 45-14039
It is described in the publication No. 1, and is well known. These thermal recording sheets are currently used as office copy paper, various recorders,
It is widely used as recording paper for electrocardiographs, calculators, combiator terminals, facsimile machines, etc.

However, in the above-mentioned conventional method, if the printing is mistakenly heated after printing, the background becomes colored and the printing becomes unreadable, and there is a possibility that the printing may be tampered with.Therefore, improvements are strongly desired.

The present inventors conducted research with the intention of providing a fixable heat-sensitive recording medium that solved this problem, and first developed a reaction between a diazonium salt and a coupler compound using a guanidine compound having a specific general formula as a basic substance. He discovered that by using a conductor, it would be possible to provide a heat-sensitive recording medium that is highly sensitive and has excellent storage stability, and he proposed it. (Unexamined Japanese Patent Publication No. 57-45094, No. 57-125091@1).

However, unlike the dyes used in leuco-based thermal paper, the azo dyes that form the color correction in such diazo-fixed thermal recording materials cannot be erased by plasticizers, etc.; Contact with polar or non-polar organic solvents, edible oil, etc. may cause part of the dye to dissolve in the solvent, causing blurring of the W@ image. If necessary, a protective layer may be provided on the photosensitive and heat sensitive layer. That is required.

As a result of studying a protective layer suitable for such a diazo-fixed heat-sensitive recording material, the present inventor found that it has good barrier properties (film-forming properties), is transparent and has good thermal conductivity, and is not colored or discolored by heat. Therefore, polyvinyl alcohol is suitable, and as a result of further investigation, we found that using a combination of high saponification degree polyvinyl alcohol with a saponification degree of 95% or more and a nonionic surfactant with an HLB of 10 or more is effective for chemical resistance. It has been found that this method is the best for obtaining a diazo-fixed heat-sensitive recording material which has good properties and excellent storage stability.

In other words, if so-called partially saponified polyvinyl alcohol with a saponification rate of 95% or less is used as a protective layer, the chemical resistance will certainly improve due to the provision of the protective layer, but at the same time the raw storage stability will be poor. This is because the coupling reaction between the diazonium salt and the coupler compound is easily accelerated in polar solvents such as water, and background fogging is more likely to occur under conditions of high temperature and humidity than with ordinary leuco dye-based thermal paper. This is thought to be due to the fact that partially saponified polyvinyl alcohol has a higher equilibrium moisture content and absorbs moisture more easily than fully saponified polyvinyl alcohol.However, when a protective layer is provided only with highly saponified polyvinyl alcohol, Since organic substances such as coupler compounds and organic basic compounds are dispersed in the form of fine particles in the photosensitive and thermosensitive layer, the affinity for both of the above compounds is poor, and chemical resistance is good because a dense film is not formed. do not have.

As a result of considering this problem 71] 1, it was found that a nonionic field 1 with a hydrophilic and lipophilic balance HLB of 10 or more
1&: We have found that this can be achieved by particularly containing 3% to 0.01% (Tft%) of the 0 activity rule to highly saponified polyvinyl alcohol.

The use of ionic surfactants such as anionic and cationic surfactants is necessary when forming a protective layer because the photosensitive and thermosensitive layer contains an organic basic compound and an acid compound to prevent pre-coupling. The liquid becomes unstable, which is not desirable. On the other hand, by using the above-mentioned nonionic surfactant, a uniform coating film with no uneven coating can be obtained, and even when a solid black image is produced, there is no flame unevenness in the image and the resolution is excellent. , very good images can be obtained.

However, since the coupling reaction of the diazonium salt with the coupler compound is promoted in a polar solvent such as water, the HLB is 10.
When the following surfactants with relatively strong hydrophobicity are added, a coupling reaction occurs, resulting in a decrease in color density. In this regard, as in the present invention (when a relatively highly hydrophilic nonionic surfactant with an HLB of 10 or more is used in combination with a high saponification degree polyvinyl alcohol having a saponification degree of 95% or more), color development is possible. Not only is the decrease in m degrees reduced, but also a uniform coating film with no uneven coating can be obtained, so that a diazo-fixed heat-sensitive recording material with excellent chemical resistance can be obtained.

In addition, if the amount of nonionic surfactant added to the binder is less than 0.01%, the above-mentioned excellent effect will not be exhibited, and even if it is added more than -30,000%, the effect will be saturated. Only the cost disadvantage will increase.

Nonionic surfactants which are conveniently used in the present invention and exhibit remarkable effects are widely used in terms of materials, and specific examples thereof are as follows.

■ Polyoxyethylene alkyl ethers no (
0,)I, O) nn ■ Polyoxyethylene alkyl phenol ethers ae o (o鵞H40)口H ■ Polyoxyethylene alkyl esters ROOO(
Ot H40) * H O sorbitan alkyl ester ■ Polyoxyethylene sorbitan alkyl ester ＾ HO (0, H, O) n'H Note that the above 几 is a fatty chain, and n, n', and n' are 1 or more. is an integer.

Specific examples include polyoxyethylene behenyl ether, polyoxyethylene reduced lanolin, polyoxyethylene hydrogenated castor oil, nrubitan monostearate, glycerin monostearate, and polyoxydiethylene nonylphenyl ether, but there are a wide variety of surfactants. Although it is modified slightly by each manufacturing company, the HLB is 1.
As long as it is a nonionic surfactant of 0 or more, it can be used for the purpose of the present invention. Further, a surfactant having an HLB of 10 or more may be used alone, but may be used in combination as long as the overall HLH is 10 or more.

Further, in the protective layer, if necessary, a water-resistant agent such as formalin, glyoxal, chromium alum, glutaraldehyde, melamine/formalin resin, urea/formalin resin, etc., which is usually used in water-soluble polymer binder materials, can be used. .

Furthermore, if necessary, inorganic or organic pigments and other additives commonly used in the field of thermal paper may also be used.

In addition, as for the organic basic compound used in the heat-sensitive layer, generally known compounds can be used, but in particular, by using guanidine derivatives of the following general formulas (I) and (2), high sensitivity can be achieved. Moreover, a diazo-fixed heat-sensitive recording material having excellent storage stability can be obtained.

General formula (I) K.

General formula (m [wherein R15ELt, Rj, R4 and R3 are hydrogen, alkyl having 18 or less carbon atoms, cyclic alkyl, aryl, aralkyl, amino, alkylamino, acylamino, carbamoylamino, heterocyclic residues] %”6
is lower alkylene, phenylene, naphthikilene, so,
, s, Ss, o, -NH- or - double bond f: represents], and the aryl group in the formula is lower alkyl, alkoxy,
Also included are those having substituents selected from nitro, acylamino, alkylamino groups and halogens. ] 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, 3-chloro-4-N,N-dimethylaminobenzenediazonium 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-phenylaminobenzene) azonium 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 chloro+7)', 4-hairylmercapto-
Examples include 2,5-dimethoxybenzenediazonium chloride.

Furthermore, an acid compound can be used in the photosensitive and thermosensitive layer to stabilize the diazonium salt and prevent pre-coupling.
Any organic or inorganic acid compound used in conventionally known diazo type copying materials can be used. Specific examples include tartaric acid, citric acid, boric acid, lactic acid, gluconic acid, η-phosphoric acid. , trichloroacetic acid, dichloroacetic acid, cyanacetic acid, cyanoacetic acid, malonic acid, maleic acid, and the like are all preferably used.

It is preferable to use these oxides in a weight ratio of 1.0% to 30%, more preferably 5 to 15%, based on the organic basic compound.

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 coupler compounds include phenol derivatives, oxynaphthalene derivatives, compounds containing active methylene groups, and specific examples of these compounds include the following compounds.

(I) Phenol derivatives pyrocatechol resorcin phloroglycine pyrogallol meta-aminophenol para-aminophenol diethylaminophenol N-lauryl-para-aminophenol N-acyl-meta-aminophenol 3.3', 5-trihydroxydiphenyl 3.3',
5.5'-Tetrahydroxydiphenyl alpha-resorcinic acid beta-resorcinic acid r-resorcinic acid phloroglucinic acid gallic acid diresorcinol sulfide diresorcinol sulfoxide 3.5-resorcinic acid ethanolamide 2.4-resorcinic acid ethanol Amide 4-Bromresorcin 4-Chlororesorcin 2-Methylresorcin 3.37-Butylenedioxydiphenol3.3'-EthylenedioxydiphenolBisphenol (2oxynaphthalene derivative2.3-Dihydroxynaphthaleneβ-su7tol α-Naphthol 1.6-dihydroxynaphthalene 2.3-dihydroxynaphthalene-6-sulfonic acid 2-
Naphthol-3,6-disulfonic acid 1,8-dihydroxynaphthalene-8-sulfonic acid 2-hydroxy-3-naphthoic acid-N-β-hydroxyethyl-amide 2-hydroxy-3-naphthoic acid-N,N-bis ! -Hydroxyethylamide 5-(paranitro)-benzamide-1-naphthol 1
-S7toll-3-(N-β-hydroxyethyl)-sulfone-amide 2-hydroxy-3-propylmorpholinonaphthoic acid 2
-Hydroxy-3-naphtho-0-toluicide 2-hydroxy-3-naphthoic acid morpholinopropylamide 2-hydroxy-3-naphthoic acid IvR-4'-chloroanilide 2-hydroxy-3-naphthoic acid moromi-5'-chloro-2 ′
.

4'-Dimethoxyanilide 2-hydroxy-3-naphtho, 2',5'-dimethoxyanilide 2-hydroxy-3-naphtho, m-2'-ethoxyanilide 2-hydroxy-3-naphtho, d -2'-methoxyanilide 2-hydroxy-3-naphthoic acid-phenyl ester 2-hydroxy-3-naphtho; acid-47-phethoxyanilide 2-hydroxy-3-nando, x#-
4'-pendeloxyanilide 2-hydroxy-3-su7-4'-phenethyloxyanilide 2-hydroxy-3-nat4-2'-pendeloxyanilide 2-
Hydroxy-3-su7t:1#2',5'-dimethylanilide 2-hydroxy-3-nando4-4'-methoxyanilide (3) Compound containing active methylene group l-
Phenyl-3-methyl-hyrazolone (5) Acetoacetic acid anilide 1-Phenyl-3-carboxybilasolone Acetoacetic acid Cyclohexylamide Acetoacetic acid Benzylamide Cyanoacetanilide Cyanoacetomorpholine 4-Carboxy-acetoacetanilide These coupler compounds can be incorporated into the light and heat sensitive layer as a fine particle dispersion with a particle size of 10 μm or less using a fractional means such as a ball mill, sand grinder, attritor, etc.

Also, the coupler compound is 1'! 4Ii or two or more may be combined to produce a dye exhibiting desired spectral absorption characteristics.

Furthermore, during dispersion, the coupler compound may be dispersed alone, but it may also be co-dispersed with an organic basic compound or 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 if the dissolved layer in water at 20 ° C is less than x, op 7, it has good humidity and heat storage stability. , aliphatic amines, pyrrolidine derivatives, imidazole derivatives, imidacillin #s4, piperidine derivatives, etc. may also be suitably used, but in particular compounds of the following general formula (
When hydrophobic guanidine d4 (I) and (2) is used as a color developer, it has excellent storage stability under high temperature and high humidity conditions, and also has excellent storage stability as the image fades rapidly. It is possible to obtain a diazo-static 5# type heat-sensitive recording material.As a color developer, one having a temperature of 100 to 170 DEG 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.

General formula (I) or +tl 几4 [in the formula, "
I. ,,s,,s,
o, -NH- or - double bond as shown in Table f), and the aryl group in the formula includes those having a substituent selected from lower alkyl, alkoxy, nitro, acylamino, alkylamino groups and halogen] Representatives thereof Specific examples are shown in Table 1.

Table-1 N.H. N.H. N.H. NH3 (g) Oh.

Oh.

NO! LJI-+3 1NflH H H N
N (34) (3s
)NH, -0-NH.

(42') (43
) These guanidine derivatives shown above can be easily synthesized by known methods or methods similar thereto.

The light and heat sensitive layer of the present invention contains a diazonium salt, a coupler compound, a color developer, etc. as main components, and these may be provided as a single layer on a support as a light and heat sensitive layer.
It may be provided on a support in layers or in multiple layers.

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, hydroxyethyl cellulose, carboxymethyl cellulose, polyacrylamide, carboxymethyl starch, dialdehyde starch, etc. starch or its modified products and derivatives, polyvinyl alcohol or its modified products and derivatives, polyvinylpyrrolidone, imbutylene-
Examples include synthetic resin emulsions such as maleic anhydride copolymer, polyacrylate, styrene-maleic anhydride copolymer, polyvinyl chloride, polyvinylidene chloride, polystyrene, methacrylate, polypropylene, polyacrylonitrile, and acrylic ester. These binder materials can be used alone or in combination, but since the coupling reaction of diazonium salts is promoted in polar solvents such as water, it is difficult to use them especially at high temperatures for fixing heat-sensitive recording materials that use diazonium salts. From the viewpoint of storage stability under high humidity, it is preferable to use a binder material having a low equilibrium moisture content.

Specific examples of pigments used in the photosensitive and heat-sensitive layer of the present invention include kaolin, calcined kaolin, talc, waxite, diatomite, styrene resin particles, calcium carbonate, aluminum hydroxide, magnesium hydroxide, magnesium carbonate, Examples include titanium oxide, barium carbonate, urea-formalin filler, cellulose filler, aluminum oxide, etc., but from the viewpoint of thermal head matching properties such as scum and sticking, JP 53-118059.54-258
45.54-118846. It is desirable to use an oil-absorbing pigment with an oil absorption of 80 to 500aj/100II according to the measuring method specified in JIS K5101, as described in 54-118847, especially in the case where the pigment is in direct contact with a thermal head. ,fAf! It is desirable to use oil-absorbing pigments that exhibit the above-mentioned oil absorption amount, such as kaolin and urea-formalin fillers.

Other auxiliary ingredients include zinc chloride, zinc sulfate, sodium citrate, guanidine thiofrea sulfate, calcium gluconate, nlubitol,
T4 such as saccharose is used, and if necessary, ultraviolet inhibitors and antioxidants may be added, and waxes and metal soaps may be used for the purpose of improving sticking and coloring sensitivity.

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, palmitic acid amide, Examples include oleic acid amide, acetamide, coconut fatty acid amide, methylolated products of these fatty acid amides, ethylene bis stearamide, ethylene bis stearamide, and higher fatty acid esters.

Examples of metal soaps include higher fatty acid polyvalent gold K14 salts, ie, zinc stearate, aluminum stearate, calcium child tearate, and oleic acid amide.

Also, as a sensitizer that increases the color development sensitivity as above, it has a melting point of 90℃~
It is also possible to use a substance that has good compatibility with the organic basic compound and Kab2 to Kasonomoke when heated at 150°C.

As these substances, any substance can be used as long as it has good compatibility during heating, 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) is suitably used. Specific examples include dimethyl terephthalate, dibenzyl terephthalate, l-methoxynaphthalene, 1,4-jethoxynaphthalene, and benzyl ether of P-hydroxybenzoic acid benzyl ester.

These can be used by dispersing them alone, but they can also be used by co-dispersing them with organic basic compounds, coupler compounds, etc.

In addition to paper, synthetic resin films, laminated paper, etc. can be used as a support. When paper is used as a support, when photosensitive and thermosensitive Ms is applied directly onto the support with iC, the diazonium salt fills the voids in the paper base. N is applied after thermal printing in order to provide peace of mind with a large amount of diazonium salt as it penetrates and impregnates the inside.
In some cases, the sensitivity of photofixing due to light may decrease, and in order to prevent this drawback, if necessary, the paper substrate may be coated with a void photonic agent such as silica sol, alumina, titanium oxide, kaolin, etc.
Alternatively, these materials are precoated with a combination of polymeric materials such as starch, casein, polyvinyl alcohol, and polyvinyl acetate emulsion, and then photo- and heat-sensitive coatings are used. 4 may be applied.

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

Example 1 A photosensitive/thermosensitive layer coating solution having the following formulation was coated onto a support so that the coating weight after drying was 9.51/rrl, and dried.

In addition, liquid A and liquid B were pounded as follows @- in a ball mill for 48 hours.
It was prepared by grinding for a while.

Solution A: A protective No. Apply so that the coating after drying + FJt is 2.01 ft, dry,
A fixing type thermosensitive recording medium is created.

Example 2 A diazo-fixing thermosensitive material was produced in the same manner as in Example 1 except that glycerin monostearate (HLn = 13.5)'Th was used instead of polyoxyethylene behenyl ether (HLR = 16.5) in Example 1. A record was created.

Example 3 Diazo determination was carried out in the same manner as in Example 1 except that polyoxyethylene nonylphenyl ether (HLH = 18.9) was used instead of polyoxyethylene behenyl ether (HLB = 16.5) in Example 1. Visual feeling fPs
0 Comparative Example 1 A recording material was prepared. A diazo-fixed thermosensitive recording material was obtained in Example 1 without using polyoxyethylene behenyl ether (HLR=16.5) and without using any surfactant. 0 Comparative Example 2 Comparison In Example 1, Poval 110 (degree of saponification 98.5%)
) instead of using Poval 210 (saponification degree 88.0%)
) A diazo-fixed heat-sensitive recording material was obtained in the same manner as in Comparative Example 1, except for using Comparative Example 1.

Comparative Example 3 Same as Example 1 except that polyoxyethylene behenyl ether (HL B = 16.5) was used in Example IVc 4) Vc glycerin monooleate (HLI (=9.5) was used) A diazo-fixed heat-sensitive recording material was obtained.

Comparative Example 4 In Example II/c, Poval 110 (degree of saponification 98.
5%) - instead of using Poval 210 (saponification degree 88
．． A diazo-fixed thermosensitive recording material was obtained in the same manner as in Example 1 except that 0%) was used.

The thus obtained diazo-fixed thermal recording material 2 was printed and recorded using a Facomfax 6210 manufactured by Fujitsu, the diazonium salt was decomposed and fixed by full-surface ultraviolet exposure, and the degree of color development was measured using a Macbeth densitometer (几D-514). ).

In addition, regarding raw storage stability, 40%
The sample was exposed to tg for 24 hours at 90% Celsius and then photofixed, and the background density was measured using RD-514.

1lIIt Chemical properties were evaluated by wiping the printed colored image as described above with a cloth coated with water:alcohol (I:l) and then evaluating the remaining rate of the image.

43 Effects of the invention: +i IS? By providing this, it is possible to obtain a highly sensitive diazo-fixed heat-sensitive recording material which has excellent chemical resistance and good shelf life.

Claims (1)

[Scope of Claims] 1. A support comprising a light-sensitive and heat-sensitive layer containing as main components a fine particle 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 the diazo-fixed heat-sensitive recording material provided above,
A diazo-fixed heat-sensitive recording material, wherein a protective film layer containing a highly saponified polyvinyl alcohol having a saponification degree of 95% or more and a nonionic surfactant having an HLB of 10 or more is provided on the photosensitive heat-sensitive layer. 2. The diazo-fixed thermal 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 number 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), and Aryl group is lower alkyl,
Also included are those having a substituent selected from alkoxy, nitro, acylamino, alkylamino groups and halogen. ]