JPH01109344A - Production of diazo copying material - Google Patents

Abstract

PURPOSE:To obviate unequal coating at the time of high-speed coating and to uniformly form a precoating layer and diazo photosensitive layer by using a coating liquid contg. a water retaining agent for the precoating layer. CONSTITUTION:The coating liquid (A) contg. the water retaining agent for the precoating layer is coated on a base material such as paper and thereafter, a photosensitive liquid contg. a diazonium compd., etc., is coated thereon to obtain the title copying material. Carboxymethylcellulose is preferably used for the water retaining agent. The coating liquid A preferably contains 1.0-4.0wt.% binder resin (e.g.: polyvinyl alcohol) and 0.01-1.0wt.% water retaining agent and further fine particle silica, etc., may be added as a concn. increasing agent thereto. The generation of the unequal coating is then obviated even if the precoating layer which functions as a barrier is formed at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing a diazo copying material for forming a copy image corresponding to an original.

<Prior art> Diazo copying materials, which utilize the reaction between a diazonium compound, which is a photodegradable compound, and a coupler to form a color, have been widely used in order to easily and inexpensively form copied images. There is.

This diazo copying material is generally composed of a base material such as paper, a diazo photosensitive layer containing the diazonium compound, etc., and a precoat layer formed between the base material and the diazo photosensitive layer. It is formed by applying a precoat layer coating liquid to the base material, then applying a photosensitive liquid containing at least a diazonium compound, and drying.

The precoat layer functions as a barrier layer to prevent the diazonium compound, etc. in the photosensitive liquid from penetrating into the substrate and making the copied image unclear. It is used in the form of an aqueous solution or dispersion containing an inorganic filler and a water-soluble polymer such as polyvinyl alcohol.

<Problems to be Solved by the Invention> However, when the precoat layer coating liquid having the above structure is applied to a substrate, uneven coating occurs, making it difficult to produce a diazo copying material having a uniform diazo photosensitive layer. That is,
When the precoat layer coating liquid with the above composition is applied to the base material,
The coating unevenness occurs probably because uneven water absorption occurs in the coating liquid, or because the viscosity of the precoat layer increases due to the rapid absorption of water by the base material and the spreadability decreases.

In particular, the above-mentioned tendency is remarkable when high-speed coating is performed to increase productivity. Therefore, even if a photosensitive liquid is applied thereafter, it is not possible to form a uniform diazo photosensitive layer, resulting in a problem that only an unclear copied image is obtained.

Moreover, if water absorption by water-absorbing substrates such as paper becomes excessive, cutting of the substrate is particularly likely to occur when long paper substrates are used for high-speed, continuous coating, resulting in reduced productivity. decreases.

In addition, after use, the composition of the coating solution for the precoat layer changes due to volatilization of water, and the viscosity of the coating solution increases, so the recovered coating solution for the precoat layer cannot be repeatedly applied under the same conditions. There is also the problem that the work efficiency decreases.

<Object of the invention> This invention was made in view of the above problems, and
The diazo copying material, which has a uniform precoat layer and diazo photosensitive layer and can form clear copied images without causing coating unevenness even under high-speed coating conditions, has been developed to improve productivity without impairing workability. It is an object of the present invention to provide a method for producing diazo copying materials that can be easily produced.

Means and Effects for Solving the Problems In order to achieve the above object, the method for producing a diazo copying material of the present invention includes coating a precoat layer coating solution containing at least a binder resin on a base material, and then In the method for producing a diazo copying material by coating a photosensitive liquid containing at least a diazonium compound, the coating liquid for the precoat layer contains a water retention agent.

According to the method for producing a diazo copying material having the above structure, since the coating liquid for the precoat layer contains a water retaining agent, absorption of moisture by the substrate can be suppressed, and a uniform precoat layer without coating unevenness can be formed. In addition, since the pre-coat layer retains water due to the above-mentioned water-retaining agent, when a photosensitive liquid is applied afterwards, the absorption of water and diazonium compounds in the photosensitive liquid is suppressed between the time of coating and the time of drying, resulting in uniform diazo A photosensitive layer can be formed.

Moreover, since a water retention agent is present in the pre-coat layer after application, it is possible to prevent excessive water absorption by the base material, and there is no risk of the base material being cut even when high-speed and continuous application is performed. do not have.

In addition, since the recovered coating solution for precoat layer contains a water retention agent, it is possible to suppress the volatilization of water during coating, etc., and also suppress changes in the concentration and viscosity of the recovered coating solution for precoat layer. It can be used repeatedly for coating under the same conditions.

The present invention will be explained in detail below.

The method for producing a diazo copying material of the present invention comprises a step of applying a precoat layer coating liquid onto a substrate, and a step of applying a photosensitive liquid containing at least a diazonium compound.

As the base material, papers of various basis weights can be used depending on the purpose.

Then, in order to prevent uneven coating even during high-speed coating, a precoat layer coating liquid containing at least a binder resin and a water retention agent is applied to the base material.

Examples of the binder resin include natural polymers such as starch, dextrin, and gum arabic, and synthetic polymers such as polyvinyl acetate emulsion, acrylic polymers, polyvinylpyrrolidone, and polyvinyl alcohol. Among these binder resins, polyvinyl alcohol is preferred because of its excellent coating properties.

As water retention agents, cellulose-based agents such as carboxymethyl cellulose, methyl cellulose and modified products thereof, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium salt of cellulose sulfate, and hydroxyethyl-2-hydroxypropyl-N-trimethylammonium chloride derivatives are used. In addition to water-soluble polymers, polyacrylic acid and its salts, starch-acrylic acid graft copolymers, starch-acrylonitrile copolymers, saponified products of methyl methacrylate-vinyl acetate copolymers, crosslinked polyacrylic acids and their Water-absorbing polymers such as salts, crosslinked polyvinyl alcohol and modified products thereof, crosslinked polyacrylamide and modified products thereof, and crosslinked polyethylene oxide are included.

Note that the water absorbing polymer may have an appropriate water absorption rate, but the water absorption rate is 0.5 to 5 times, preferably 0.5 to 2 times.
Preferably twice as much. If the water absorption rate is less than -0.5 times, the function as a water retention agent will decrease;
If the amount exceeds twice that, it becomes gel-like and difficult to apply uniformly.

Among the water-retaining agents, carboxymethyl cellulose, which has excellent compatibility with the binder resin and has appropriate water-retention properties, is preferred. As the carboxymethyl cellulose, a suitable degree of etherification can be used depending on the desired water retention property, that is, a ratio of substitution of all hydroxyl groups with carboxymethyl groups, but the degree of etherification is about 0.5 to 1.0. Preferably. When the degree of etherification is less than 0.5, water retention is insufficient and uneven coating tends to occur. Note that the carboxymethyl cellulose can also be used in the form of a sodium salt or the like in order to increase water solubility.

The above-mentioned binder resin can be used in an appropriate amount in the pre-coat layer coating solution depending on its type, etc., but 1.
Preferably, it is used in an amount of 0 to 4.0% by weight. Binder resin is 1
．． If the binder resin content is less than 0% by weight, the film forming properties will not be sufficient and it will be difficult to form a uniform precoat □ layer and even a diazo photosensitive layer.If the binder resin content exceeds 4.0% by weight, the coating solution for the precoat layer will be difficult to form. The fluidity of the coating decreases, making it difficult to coat uniformly, especially under high-speed coating conditions.

In addition, the water retention agent can be used in an appropriate amount depending on the type and desired water retention property, but 0.01 to 1.0ffi amount %,
Preferably 0.1-0. Preferably, 5i1ffi% is used. If the water retention agent is less than 0.01% by weight, the water retention is insufficient, and it is difficult to uniformly form a precoat layer and, by extension, a diazo photosensitive layer. II amount%
If it exceeds 100%, the viscosity of the precoat layer coating solution tends to increase, making it difficult to apply it uniformly. This risk is particularly high when coating is performed at high speed.

When the precoat layer coating liquid having the above composition is used, uniform coating can be performed with a small amount of water retention agent.

More specifically, probably because of the good compatibility between the binder resin and the water retention agent, absorption of water by the base material can be suppressed with a small amount of the water retention agent, and uniform coating can be achieved.

Particularly, when polyvinyl alcohol and carboxymethyl cellulose are used in combination among the binder resin and water retention agent, they have excellent compatibility and can be applied more uniformly.

Further, in order to improve the coloring property, coloring density, etc., the coating liquid for the precoat layer preferably contains a density increasing agent together with a binder resin and a water retention agent.

“The above-mentioned concentration increasing agent includes, for example, fine particle silica,
Inorganic fillers such as talc, kaolin, calcium carbonate, barium sulfate, magnesium oxide, pallite, and alumina are exemplified, and these concentration increasing agents number 18! Alternatively, 28 or more may be mixed and used in an appropriate amount.

Among the above concentration increasing agents, fine particle silica such as colloidal silica and hydrophobic silica is preferred.

The coating liquid for the precoat layer is used in the form of an aqueous solution or an aqueous dispersion, and usually has a coating amount of 0.5 after drying.
Approximately 5 g/g is applied.

After applying the above precoat layer coating liquid, a photosensitive liquid containing at least a diazonium compound is applied. The diazonium compounds include various conventionally known diazonium compounds that are photodegradable and develop color by reacting with couplers, such as 4-diazo-N, N-dimethylaniline, 4-diazo-N, N-diethylaniline. , 4-diazo-N-ethyl-N-β-hydroxyethylaniline, 4
-Diazo-N, N-bis-β-hydroxyethylaniline, 4-diazo-N-methyl-N-β-hydroxyethylaniline, 4-diazo-N-methyl-N-β-hydroxypropylaniline, 4-diazo- N-ethyl-N-
(β-diethylaminoethyl)aniline, 4-diazo-
2-chloro-N.

N-diethylaniline, 4-diazo-2-methyl-N,
N-diethylaniline, 4-diazo-2-iodo-N,
N-diethylaniline, 4-diazo-2-trifluoromethyl-N, N-diethylaniline, 4-diazo-N-
Methyl-N-benzylaniline, 4-diazo-N-ethyl-N-benzylaniline, 4-diazo-2,5-dibutoxy-N, N-diethylaniline, 4-diazo-2,
5-Jethoxy-N-benzoylaniline, 4-diazo-2,5-jethoxy-N-ethyl-N-benzoylaniline, 4-diazo-2,5-dibenzyloxy-N-
Benzoylaniline, 4-diazo-2-chloro-5-methoxy-N-benzoylaniline, 4-diazo-2,5
-jethoxy-N-benzoyl-N-methylaniline,
4-Diazo-2,5-jethoxy-N-benzoyl-N
-Hydroxymethylaniline, N,N-bis(p-diazophenyl)amine, 4-diazo-2,5゜4'-triethoxydiphenylamine, 4-diazo-2,5,4'
-triethoxydiphenyl, 4. -4'-bisdiazo-
2,2', 5,5'-tetrahydroxydiphenylmethane, 4,4'-bisdiazo-3,3'-dichloro-5,5'-dimethoxydiphenyl, 4-diazo-2,
5-dimethoxyphenylethyl sulfide, 4-diazo-2,5-jethoxy-4'-methyl-diphenyl sulfide, 4-diazo-2,5-dibutoxy-1-morpholinobenzene, 4-diazo-2,5-jethoxy- 1-
Morpholinobenzene, 4-diazo-2-methoxy-1-
Thiomorpholinobenzene, N-(4-diazophenyl)
piperidine, N-(4-diazophenyl)pyrrolidine,
N-(4-diazo-2,5-di-n-butoxyphenyl)piperidine, 2-diazo-4-methylthio-N,N-
Examples include dimethylaniline, 2-diazo-5-benzoylamino-N, N'-dimethylaniline, and 2-diazo-1-naphthol-5-sulfonic acid.

These diazonium compounds include diazonium salts with hydrochloric acid and sulfuric acid; double salts with cadmium chloride, magnesium chloride, tin chloride, zinc chloride, etc.; complex salts with fluoroboric acid;
When the compound has a sulfo group, it is used as a sodium salt.

The above diazonium compounds may be used alone or in combination of two or more.

Further, as the coupler which develops color by reacting with the diazonium compound, conventionally known couplers such as pyrocatechol, resorcin, phloroglycin, pyrogallol, resorcin monoglycol ether, resorcin glycol ether, m-aminophenol, p-amino Phenol, diethylaminophenol, o (2-
hydroxyethoxy)phenol, 2.5.6-)limethylphenol, 2-hydroxymethylphenol, β
-(2-hydroxyphenyl)propionic acid, 2-(anilinomethyl)phenol, β-(4-methyl-2-hydroxyphenyl)glutaric acid, 2,5-dimethyl-6
-(dimethylaminomethyl)phenol, 1,3-dimethoxypyrogallol, p-(N-laurylamino)phenol, m-(N-acetylamino)phenol, m-
Hydroxy-acetanilide, 2,5-dimethyl-4-
Morpholinomethylphenol, 2-methyl-5-isopropyl-4-morpholinomethylphenol, 4-morpholinomethylresorcinol monomethyl ether, 3.3
', 5-trihydroxydiphenyl, 3.3', 5
．． 5'-tetrahydroxydiphenyl, 2.2',
4.4'-tetrahydroxydiphenyl, 2.4.4
'-trihydroxydiphenyl-2'-sulfonic acid,
2.4, 6.3'.

5'-pentahydroxydiphenyl% 2* 2'
+4.4'-tetrahydroxydiphenyl sulfide, 2.3-dihydroxynaphthalene, α-naphthol,
β-naphthol, 1,6-dihydroxynaphthalene, 2
, 7-dihydroxynaphthalene, 1-hydroxynaphthalene-4-sulfonic acid, 2゜3-dihydroxinaphthalene-6-sulfonic acid, 2-hydroxynaphthalene-3
, 6-disulfonic acid, 2.7-dihydroxynaphthalene-3-sulfonic acid, 2.8-dihydroxynaphthalene-
6-'sulfonic acid, 1,8-dihydroxynaphthalene-
6-sulfonic acid, 1-hydroxy-8-aminonaphthalene-5-sulfonic acid, 2,7-cyhydroxynaphthalene-3,6-disulfonic acid, 1-hydroxy-8-benzoylaminonaphthalene-2-sulfonic acid, 2 -hydroxy-3-[N-(2-aminoethyl)carbamoyl]naphthalene, 2-hydroxy-3-[N,N-bis(2-
aminoethyl)carbamoyl]naphthalene, 8-hydroxy-2-[N-(2-aminoethyl)carbamoyl]
Naphthalene, 1-(N-carboethoxymethylamino)
-8-hydroxynaphthalene-4-sulfonic acid, 5-
(p-nitrobenzamide)-1=hydroxynaphthalene, N-(1-hydroxynaphthalen-7-yl)-N
'-Phenylguanidine, N-(2-hydroxynaphthalen-8-yl)guanidine, 1-hydroxynaphthalene-3-(N-β-hydroxyethyl)sulfonamide, 1-hydroxynaphthalene-3-(N-o-methoxy phenyl)sulfonamide, N,N-bis[5-oxy-7-sulfo-2-naphthyl]amine, N,N-bis[1-oxy-3-sulfo-6-naphthylcothiourea, 1-phenyl- 3-methylpyrazol-5-one, acetoacetanilide, 1-phenyl-3-carboxypyrazol-5-one, acetoacetate cyclohexylamide,
Acetoacetic benzylamide, cyanoacetamide, N-
(cyanoacetyl)morpholine, 1-(3-sulfamidophenyl)-3-methylpyrazol-5-one, 1-
(4-carboethoxyphenyl)-3-dodecylpyrazol-5-one, naphtho[2°1-d]imidazole,
2-Methyl-4-hydroxybenzimidazole, 7-
Examples include methyl-4-hydroxybenzothiazole, 1,7-dimethyl-4-hydroxybenzotriazole, 3-hydroxythiophene-5-carboxylic acid, and 1,3,4-cyclopentatrione. These couplers can be used in the form of hydrochloride, sulfate, sodium salt, etc., and can be used alone or in combination of two or more.

When the development method of the diazo photosensitive layer is a wet development method (-component system), the above coupler is contained in the alkaline solution that is the developer, and when the development method of the diazo photosensitive layer is a dry development method or a wet development method (
In the case of a two-component system such as a two-component system) or a three-component system such as a heat development method, it is contained in the diazo photosensitive layer together with the diazonium compound.

The photosensitive solution contains an organic stabilizer such as sulfosalicylic acid, p-toluenesulfonic acid, citric acid, tartaric acid, oxalic acid, sulfamic acid, formic acid, maleic acid, phosphoric acid, etc. as a stabilizer for the above-mentioned diazonium compound. It is preferable to blend an acid or an inorganic acid.

The photosensitive solution also contains stabilizing aids such as zinc chloride, sodium carbonate, aluminum sulfate, sodium phosphate, thiourea, and allylthiourea; and polyhydric alcohols such as glycerin, ethylene glycol, diethylene glycol, and propylene glycol. Development accelerator: Dissolution aid consisting of sodium salts of naphthalene trisulfonic acid, sulfosalicylic acid, allylsulfonic acid, etc. Blue dyes such as methylene blue and patent blue, dyes such as fluorescent whitening agents; Fluorinated polyethylene, polyethylene Contains various additives such as lubricants such as wax; uniform coating agents such as saponin, antifoaming agents, and surfactants such as acetylene alcohols and acetylene glycols; binder resins such as water-soluble resins; and fillers. You can leave it there.

The photosensitive liquid mentioned above is used in the form of an aqueous solution or an aqueous dispersion,
Usually, the coating after drying is applied at a rate of about 5 to 5 z/rd. Note that, as described above, since the coating liquid for the precoat layer can be uniformly applied without causing coating unevenness, the diazo photosensitive layer can also be uniformly formed.

A back coat layer for preventing the base material from curling may be formed on the surface of the base material that is not coated with the coating liquid for the precoat layer. As the back coat layer, one containing the polyhydric alcohol, binder resin, lubricant, etc. in the diazo photosensitive layer described above is used.

The diazo copying material obtained as described above can uniformly form a precoat layer and a diazo photosensitive layer, so it can be processed by exposing the original image to light and using a developing method such as a wet developing method, a dry developing method, or a heat developing method. By developing it, a clear copy image can be formed.

When the diazo photosensitive layer is developed by a wet development method, an alkaline solution is used as the developer, as described above. The alkaline solution usually contains components such as the above-mentioned couplers in addition to an alkaline agent, an anti-discoloration agent, and a solvent such as water.

Examples of the alkaline agent include sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, calcium carbonate, potassium tetraborate, etc., and examples of the discoloration inhibitor include thiourea, sodium thiosulfate, etc. .

When the diazo photosensitive layer is developed by the above-mentioned dry development method, it is generally developed by a two-component wet development method using a developer consisting of ammonia gas and water vapor. In some cases, a developer consisting of an alkaline agent, the above-mentioned development accelerator, a wetting agent, an anti-discoloration agent and a solvent is used. The alkaline agents used in these two-component developing methods include ammonia, monoethanolamine, jetanolamine, triethanolamine, morpholine,
Examples include guanidine.

In addition, when developing by the above-mentioned heat development method, since an alkaline agent is contained in the diazo photosensitive layer, a developer is not required.
The diazonium compound and the coupler may be heated to react and develop a color.

<Examples> The present invention will be described in more detail below based on Examples.

Example 1.2 and Comparative Example 1.2 Preparation of coating solution for pre-coat layer Fine particle silica 0.3 fflffi% as concentration increasing agent
, polyethylene wax 0.25ffif as lubricant
fi% and a polymerization degree of 70 as a binder resin.
A coating wave for a precoat layer in the form of an aqueous dispersion was prepared, containing polyvinyl alcohol of 0.0 and carboxymethyl cellulose as a water retention agent in the proportions shown in the table.

Preparation of Photosensitive Solution A photosensitive solution was prepared by adding water to materials having the following composition and making the total amount 1 electrified.

Diazonium salt = 4-diazo-N,N-dimethylaniline l/2 ZnCl2 10g Coupler: 2.3-dihydroxynaphthalene-6-sodium sulfonate 15.0° Stabilizer: Tartaric acid
8.5g Stabilizer: Zinc chloride
24.0g Thiourea 220
゜Development accelerator Nidiethylene glycol 22.0゜Dye 05゜Preparation of diazo copying material Using roll paper for diazo copying paper as the base material, use a coater to coat each of the above precoat layers at a speed of 1000 m/hour. Applying the liquid after dryingj12. Or/rrr
At the same time, the above-mentioned photosensitive liquid was applied so that the coating amount after drying was 1.0 g/rrr, and dried to prepare a diazo copying material.

For each of the obtained diazo copying materials, the state of coating unevenness was visually observed and evaluated according to the following criteria.

◎: No uneven coating, o: Slight uneven coating, X:
The coating is noticeably uneven.

The results are shown in the table.

As is clear from the coating above, the diazo copying material of Comparative Example 1 was prepared using a precoat layer coating solution that did not contain carboxymethyl cellulose as a water retention agent, and the precoat layer coating solution did not contain polyvinyl alcohol as a binder resin. In all of the diazo copying materials of Comparative Example 2 prepared using the liquid, significant coating unevenness was observed. On the other hand, it was found that the diazo copying materials prepared using the precoat layer coating liquids of Examples 1 and 2 had little or no coating unevenness.

In addition, in the diazo copying materials of each of the above examples and comparative examples,
When a predetermined original image was exposed to light and developed by a dry developing method to form a copied image, the images in Comparative Examples 1 and 2 were unclear.

On the other hand, with the diazo copying materials of Examples 1 and 2, clear copied images were obtained even with the diazo copying materials of Example 1, which had slight coating unevenness.

<Effects of the Invention> As described above, according to the method for producing a diazo copying material of the present invention, since the coating liquid for the precoat layer contains a water retention agent, it can be coated without uneven coating even under high-speed coating conditions. , a diazo copying material having a uniform precoat layer and a diazo photosensitive layer and capable of forming clear copied images,
It has the unique effect of being able to be manufactured with high productivity without impairing workability.

Claims (1)

[Scope of Claims] 1. A method for producing a diazo copying material by applying a precoat layer coating solution containing at least a binder resin onto a substrate, and then coating a photosensitive solution containing at least a diazonium compound, the method comprising: A method for producing a diazo copying material, characterized in that the precoat layer coating liquid contains a water retention agent. 2. The method for producing a diazo copying material according to claim 1, wherein the water retention agent is carboxymethylcellulose. 3. The coating liquid for the pre-coat layer contains a binder resin of 1.0 to 4.0.
% by weight and 0.01 to 1.0% by weight of a water retention agent.