JPH02242256A - Production of positive type photosensitive coating solution and positive type photosensitive printing plate - Google Patents

Abstract

PURPOSE:To reduce the toxicity of a coating soln., to improve the coating performance and to make a printing plate free from pinholes and ununiformity in lines by incorporating a high molecular compd. contg. o-quinonediazido groups and ethyl lactate. CONSTITUTION:This coating soln. contains a high molecular compd. (A) contg. o-quinonediazido groups and a slightly malodorous ethyl lactate dissolving the compd. A and having low toxicity. The compd. A may be a product obtd. by esterifying phenol-formaldehyde resin with o-naphthoquinonediazidosulfonic acid. A positive type photosensitive printing plate is preferably produced by coating a support such a a grained Al plate with this coating soln. and drying this soln.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for producing a positive-working photosensitive coating liquid and a positive-working photosensitive printing plate. The present invention relates to a mold photosensitive coating liquid and a method for producing a positive photosensitive printing plate.

[Background of the Invention] A positive-working photosensitive printing plate is manufactured by dissolving a photosensitive composition in a suitable solvent, applying it to a support, and drying it. Conventionally, such a positive-working photosensitive printing plate During the production of printing plates, various solvents are used to dissolve the photosensitive composition, such as glycol ethers such as methyl cellosolve (ethylene glycol monomethyl ether) and ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, etc. Cellosolve esters are mainly used.

However, these coating solvents have the problem of being highly toxic during the production of photosensitive printing plates, as well as having a strong odor.
It is uncomfortable and unfavorable in terms of the working environment.Furthermore, when a photosensitive composition is coated on a support using the above-mentioned solvent, coating properties are poor, and streaks and pinholes often occur, which reduces the value of the product as a product. In particular, when a polymer compound containing a positive orthoquinonediazide group is used as a photosensitive composition, this polymer compound has a relatively large molecular weight, so it may be difficult to use a photosensitive composition consisting of this polymer compound and the above-mentioned coating solvent. When a photosensitive coating liquid is applied to a support, the resulting positive-working photosensitive printing plate has a problem of poor coating properties.

Therefore, as a result of various studies regarding the above-mentioned problems, the present inventors have found that when using a polymer compound containing an orthoquinone diazide group as a positive-working photosensitive composition, it is necessary to use a specific solvent to make the photosensitive composition. The present inventors have discovered that by producing a coating liquid, a positive-working photosensitive printing plate with low toxicity during production of a photosensitive printing plate and improved coating properties can be obtained, and has now completed the present invention.

[Object of the Invention] The object of the present invention is to provide a positive-working photosensitive coating liquid and a positive-working photosensitive printing plate with low toxicity, alleviated odor, and improved coating properties during the production of photosensitive printing plates. The purpose is to provide a method.

[Structure of the Invention] The objects of the present invention are as follows: 1) A positive photosensitive coating liquid containing a polymer compound containing an orthoquinonediazide group and ethyl lactate.

2) Each achieved by a method for producing a positive-working photosensitive printing plate, which is characterized by coating a support with a positive-working photosensitive coating solution containing a polymer compound containing an orthoquinonediazide group and ethyl lactate and drying it. be done.

The present invention will be explained in more detail below.

The coating solution obtained by dissolving in the solvent used in the present invention contains a positive photosensitive composition, and this positive photosensitive composition is mainly composed of a polymer compound containing an orthoquinone diazide group. Here, the polymer compound containing an orthoquinonediazide group is a reaction product of a compound containing an orthoquinonediazide group and an alkali-soluble resin, or a mixture of a compound containing an orthoquinonediazide group and an alkali-soluble resin. It is used to mean either or both cases.

Typical examples will be explained below.

As a polymer compound containing an orthoquinonediazide group,
For example, ester compounds of 0-naphthoquinonediazide sulfonic acid and polycondensation resins of phenols and aldehydes or ketones may be mentioned.

Examples of the phenols include phenol, 0
-cresol, m-cresol, p-cresol, 3.
Examples include m-phenols such as 5-xylenol, carvacrol, and thymol, dihydric phenols such as catechol, resorcinol, and hydroquinone, and trihydric phenols such as pyrogallol and phloroglucin.

Examples of the aldehyde include formaldehyde, benzaldehyde, acetaldehyde, crotonaldehyde,
Examples include furfural.

Preferred among these aldehydes are formaldehyde and benzaldehyde.

Furthermore, examples of the above-mentioned ketones include acetone, methyl ethyl ketone, and the like.

Specific examples of the polycondensation resin include phenol/formaldehyde formaldehyde resin, I-, O-mixed cresol/formaldehyde resin, resorcinol/benzaldehyde resin, pyrogallol/acetone resin, and the like.

The condensation rate of 0-naphthoquinonediazide sulfonic acid with respect to the 011 group of the phenol in the 0-naphthoquinonediazide compound (reaction rate with respect to one 011 group) is 15 to 8.
It is preferably 0%, more preferably 20-45%.

Further, as the O-quinonediazide compound used in the uninvented invention, the compound described in JP-A-58-43451 can also be used.

Among the above 0-quinonediazide compounds, an 0-quinonediazide ester compound obtained by reacting 12-benzoquinonediazide sulfonyl chloride or 1,2-naphthoquinonediazide sulfonyl chloride with a pyrogallol acetone condensation resin or 2,3,4-trihydroxybenzophenone. is most preferred.

As the O-quinonediazide compound used in the present invention, each of the above compounds may be used alone, or two or more types of compounds may be used in combination.

The polymer compound containing 0-quinonediazide used in the present invention preferably has a molecular weight of 1,500 or more, more preferably 2,000 or more, in view of coating properties.

The above-mentioned 0-quinonediazide compound is preferably used in combination with an alkali-soluble resin. Examples of the alkali-soluble resin include novolak resin, a vinyl polymer having a phenolic hydroxyl group, and those described in JP-A-55-57841. Examples include condensation resins of polyhydric phenols and aldehydes or ketones. Examples of the novolac resin include phenol-formaldehyde resin, cresol-formaldehyde resin, phenol-cresol-formaldehyde copolycondensation resin as described in JP-A-55-57841, and phenol-cresol-formaldehyde copolycondensation resin as described in JP-A-55-127553. Examples include copolycondensation resins of p-substituted phenol and phenol or cresol and formaldehyde as described above.

In addition to the above-mentioned materials, these photosensitive compositions may also contain colorants such as dyes and pigments, sensitizing agents, plasticizers, surfactants, organic acids, acid anhydrides, and acids that can be removed by exposure to light. Compounds that may be generated can be added.

Dyes preferably used in the present invention include basic dyes and oil-soluble dyes. Specifically, Victoria Pure Blue BOH, Victoria Blue BH, Methyl Violet, Eisen Malachite Green (manufactured by Hodogaya Chemical Industry), Patent Pure Blue
Basic dyes such as vx10-damin B, methylene blue (manufactured by Sumitomo Chemical), and Sudan Blue 11, Victoria Blue F4R (b).

A, S, F), oil blue #603, oil
Examples include oil-soluble dyes such as Blue BO3 and Oil Blue II N (manufactured by Orient Chemical Industries).

The polymer compound containing an O-quinonediazide group used in the present invention is dissolved in ethyl lactate to form a photosensitive coating solution, which improves toxicity, odor, and storage stability. The ethyl lactate can be used alone or in combination with other solvents, and can also be appropriately mixed with two or more other solvents.

Other solvents include dimethylformamide, dimethyl sulfoxide, acetone, dioxane, tetrahydrofuran, cyclohexane, methylene chloride, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone,
Examples include diethyl ketone, cyclohexanol, alcohols such as n-butyl alcohol, benzyl alcohol, and phenethyl alcohol, and water.

When used as a mixed solvent, the proportion of ethyl lactate is preferably as large as possible, but preferably at least 10%, more preferably 30% or more, and even more preferably 50% or more.

Various supports can be used to manufacture a photosensitive printing plate by applying the photosensitive coating liquid of the present invention, and examples thereof include metal plates such as aluminum, zinc, copper, and steel; , metal plates plated or vapor-deposited with zinc, copper, nickel, aluminum, etc., paper and plastics treated to make them hydrophilic, paper and plastic films coated with metals, glass plates, resin-coated paper, metal foils such as aluminum, etc. For example, paper covered with

Among these, aluminum plates are preferred.

In particular, in the case of an aluminum plate support, it is preferable that the support be subjected to surface treatments such as graining, anodizing, and, if necessary, sealing.

As a method for carrying out the above-mentioned graining treatment, commonly used techniques such as brush polishing, ball polishing, chemical polishing, electrolytic etching, etc. are employed after degreasing the surface of the aluminum plate or the like.

The above-mentioned anodizing treatment is performed using, for example, phosphoric acid or chromic acid.

In an aqueous or non-aqueous solution of an inorganic salt such as boric acid, sulfuric acid, etc., or an organic acid such as Scheler's acid or sulfuric acid, or a mixture of two or more of these acids, an electric current is passed using an aluminum plate, etc. as an anode. It is done by

Furthermore, the sealing treatment is carried out by immersion in a hot aqueous solution of an aqueous sodium silicate solution, a mineral salt, and some inorganic or organic salts, or by a steam bath.

In the present invention, the amount of photosensitive coating liquid applied to the support is as follows:
Although it varies depending on the use, - numerically as solid content O, S ~ 3
．． 5g/a'' is appropriate.

The coating method of the present invention includes dip coating, roll coating, reverse roll coating, air doctor coating, blade coating, rod coating, knife coating, squeeze coating, gravure coating, cast coating, curtain coating, extrusion coating,
The coating film thickness is 0.1 to 5 g/m'.
is preferred, and the drying temperature is in the range of 20 to 150°C, preferably 30 to 100°C.

The developer according to the present invention is an alkaline aqueous solution that does not substantially contain an organic solvent, and the alkaline agent is preferably potassium silicate, lithium silicate, sodium silicate, sodium hydroxide, potassium hydroxide, or hydroxide. Examples include lithium, tribasic sodium phosphate, dibasic sodium phosphate, tribasic potassium phosphate, dibasic potassium phosphate, sodium carbonate, potassium carbonate, and the like. Among these, a developer containing an alkali silicate such as potassium silicate, lithium silicate, or sodium silicate is most preferable because it has good development gradation, and the composition of the alkali silicate is [S
I 02 ] / [M] = 0.5 to 1.5 (here, [5IOz ] CM] is S i 02
A developer solution containing 0.8 to 8% by weight of Sin is preferably used. Of the acid-alkali composition, this case is particularly suitable for the molar ratio [St[h]/[M]=0.5 to 0.7.
5 and 5i02 of 0.8 to 4ffi% is preferably used because it is easy to neutralize the developing waste solution due to its low concentration, while the molar ratio of 0.75 to 1.3 is preferably used. A developer containing 1 to 8% by weight of 5in2 is preferably used because it has a high buffering power and a high processing ability.

The pH (25° C.) of the developer according to the present invention is 12 or more, preferably 12.5 to 14.0. In addition, the developer contains, for example, sodium sulfite, potassium sulfite,
Water-soluble sulfites such as lithium sulfite and magnesium sulfite can be added. The preferred content of sulfite in the developer composition is 0.05-4I! In quantity%,
More preferably, it is 0.1 to t% by weight.

In addition, an anionic surfactant and an amphoteric surfactant as described in JP-A-50-51324 and an amphoteric surfactant, JP-A-59-75255 and JP-A-80-
By containing at least one of the nonionic surfactants as described in JP-A No. 111246 and JP-A No. 80-213943, or by
By containing a polymer electrolyte as described in JP-95946 and JP-A-56-142528,
It is preferably used because it can improve the wettability to the photosensitive composition and further improve the gradation. The amount of such surfactant added is not particularly limited, but is between 0.003 and 3! ! !
The concentration is preferably 0.006 to 1% by weight, and the alkali metal of the alkali silicate contains 20 mol% or more of potassium among all the alkali metals to prevent the generation of insoluble matter in the developer. It is preferable because it has a small amount of potassium, more preferably 90 mol% or more of potassium, and most preferably 100 mol% of potassium.

Furthermore, the developer used in the present invention can contain an antifoaming agent. Suitable antifoaming agents include organosilane compounds.

Various conventionally known methods can be used to develop the photosensitive lithographic printing plate according to the present invention which has been imagewise exposed with the developer as described above. Specifically, a method of immersing an image-exposed photosensitive lithographic printing plate according to the present invention in a developer solution, and a method of jetting the developer solution from a number of nozzles onto the photosensitive layer of the photosensitive lithographic printing plate according to the present invention. A method of wiping the photosensitive layer of the photosensitive lithographic printing plate according to the present invention with a sponge moistened with a developer, a method of applying a developer with a roller to the surface of the photosensitive layer of the photosensitive lithographic printing plate according to the present invention, etc. can be mentioned. Further, after applying a developer to the photosensitive layer of the photosensitive lithographic printing plate according to the present invention in this manner, the surface of the photosensitive layer can be lightly rubbed with a brush or the like.

The developing conditions can be appropriately selected depending on the developing method. - For example, in a developing method by immersion, a method is selected in which the material is exposed to a developer solution at about 10 to 40° C. for about 10 to 80 seconds.

[Operation of the invention] Since the polymer compound containing an orthoquinone diazide group used in the present invention has a molecular weight of at least 1500, it is necessary to sufficiently dissolve such a polymer compound. It sufficiently dissolves molecular compounds, has low toxicity, and has a weak odor, so when used as a coating solvent, it not only improves the working environment but also provides good coating properties.

In the following margin [Examples] The present invention will be described below with reference to Examples, but the present invention is not limited thereto.

Example A photosensitive solution having the following composition was prepared, and a solid content of 1.8 was coated on a grained aluminum plate using a roll coater.
After coating to a coating weight of g/m', it was dried to obtain Sample 1 of a photosensitive planographic printing plate.

[Photosensitive liquid] Pyrogallol acetone resin and naphthoquinone (1,2
)-Ester compound with diazide-4-sulfonic acid chloride (average molecular weight 2500) 2.3 I! Amount of phenol and m+, p- mixed cresol (each ratio 4
8:32:20) and formaldehyde 6.71 parts by weight Novolak resin synthesized from rose octylphenol and formalin 0,000 parts by weight 2-trichloromethyl-5-(β-benzofurylvinyl)- 1,3,4-oxadiazole 0.05 parts by weight Victoria Pure Blue B OH0,07! 1 part Ethyl lactate 45 Il parts Except for changing the ethyl lactate in the above photosensitive solution to the compound shown in Table 1,
Samples 2 to 5 of photosensitive lithographic printing plates were prepared in the same manner as Sample 1.

In addition, ethyl lactate, which is an organic solvent in the photosensitive solution, is used as it is, and an ester compound of pyrogallol acetone resin and naphthoquinone-(1,2)-diazide-4-sulfonic acid chloride is used as 283.4.3'. 4°, 5°−
Hexahydroxybenzophenone and naphthoquinone (1
Sample 6 of the photosensitive lithographic printing plate was prepared in the same manner except that an ester compound with ,2)-diazide-4-sulfonic acid chloride (esterification rate: 8.3%) was used.

Regarding Samples 1 to 6 thus obtained, the coating properties of the photosensitive liquid were observed for Marangoni-1 vertical streaks and pinholes.

Here, the term "marangoni" refers to hazy, spiral-like coating unevenness that occurs on the coated surface after coating and drying.

The cause of this type of coating unevenness is the Marangoni effect, which is caused by local differences in surface tension of the wet photosensitive layer due to a temperature drop accompanying the volatilization of the solvent.

Pinholes refer to circular white spots in the photosensitive layer that appear on the coating surface, and vertical streaks are unevenness in the thickness of the photosensitive layer that appears in the running direction of the support because the coating solution is not smoothed. be.

The results are shown in Table 1.

As is clear from Table 1 below, Marangoni-1
The observation results for vertical streaks and pinholes were poor. Ethyl lactate was used as the organic solvent, and 2,3°4.3',4°,5'-hexahydroxybenzophenone and naphthoquinone-(1,2)-diazide-4-sulfonic acid chloride were used as the photosensitive materials. Ester compound with (
The evaluation results were still inferior in the case where the esterification rate was 83%).

[Effects of the Invention] The present invention uses a combination of a polymer compound containing an orthoquinone diazide group and ethyl lactate, so it is less toxic and has less odor during the coating process when producing photosensitive printing plates, making it easier to work with. The environment is improved, the coating liquid has good applicability to the support, and a photosensitive printing plate of excellent quality can be obtained.

Claims (1)

[Scope of Claims] 1) A positive photosensitive coating liquid containing a polymer compound containing an orthoquinone diazide group and ethyl lactate. 2) A method for producing a positive-working photosensitive printing plate, which comprises coating a support with a positive-working photosensitive coating solution containing a polymer compound containing an orthoquinone diazide group and ethyl lactate, and drying the coating solution.