JPH0370215B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a photosensitive printing plate with improved vacuum adhesion. Conventionally, in order to closely bake a film base plate onto a photosensitive printing plate, a vacuum baking frame was generally used, and the film base plate and photosensitive printing plate were stacked between the glass plate and rubber sheet of the printing frame, and the glass plate and A method (referred to as a vacuum contact method) is used in which the film original plate and the photosensitive printing plate are brought into close contact with each other by creating a vacuum between them and the rubber sheet. In this vacuum adhesion method, various means are known for obtaining sufficient adhesion over the entire surface to be adhered in a short time. That is, before the vacuum baking process, a solid powder such as talc is applied to the surface of the photosensitive printing plate on the photosensitive layer side by mechanical means without using a dispersion medium other than a gas such as air. A method of dispersing and adhering (referred to as powdering) is disclosed in Printing Magazine 53 (10), 23 (1970), Inoue, Iino, Printing Information, 33 (11), 90 (1973), Ishiyama et al. This powdering can improve vacuum adhesion with a simple method such as applying powder or commercially available talc to prevent back transfer of printed matter using a spray gun or puff, but it also has the following drawbacks: There is.
That is, in general, powdering is often applied when using photosensitive printing plates, and the powdering operation scatters solid powder into the plate-making work room, polluting the work environment and causing various problems in the plate-making process. Moreover, it is undesirable from the viewpoint of working environment hygiene, and cleaning of peripheral equipment required after the powdering process is a problem that cannot be ignored in terms of efficiency. Further, the solid powder on the powdered photosensitive printing plate is likely to fall off during handling, causing contamination of the surrounding area, and therefore may not provide the expected vacuum adhesion. Another known method is to provide a matte layer on the surface of a photosensitive printing plate. This method improves vacuum adhesion, but the matte layer provided on the surface of the photosensitive layer prevents the developer from penetrating, worsening developability, and some of it remains in the image area after development. The matte layer tends to inhibit the affinity for ink, and furthermore, the matte layer has a strong tendency to dissolve in the developer and fatigue the developer. Furthermore, it has the disadvantage that the equipment and process for providing the mat layer are complicated and the cost is high. Therefore, as a result of intensive study on a method for improving vacuum adhesion using simple equipment and processes and without adversely affecting developability, ink receptivity, and other plate-making performance, the inventors found that The present invention has been achieved based on the discovery that if the compound is contained, the compound precipitates on the surface of the photosensitive layer and improves the vacuum adhesion. To summarize the present invention, the present invention relates to a method for producing a photosensitive printing plate, which has improved vacuum adhesion by providing a photosensitive layer on a support. A photosensitive liquid for forming a photosensitive layer contains at least one compound that has low compatibility with the photosensitive substance and the binder and has a polar group and a non-polar group in the molecule, and the photosensitive liquid is applied onto a support. By applying and drying,
It is characterized in that the above compound is caused to undergo migration or phase separation from the photosensitive layer, and at least a portion thereof is deposited on the surface of the photosensitive printing plate. The binder, which is the main component in the photosensitive layer, plays an important role in the ink receptivity and water repellency of the image area after development. On the other hand, the binder in the non-image area needs to be dissolved and removed by alkaline development. For this reason, some polar groups are introduced into the binder to impart affinity with the alkaline developer, but due to the above-mentioned role, the binder is macroscopically "lipophilic." On the other hand, since the compound used in the present invention to improve vacuum adhesion has a polar group in its molecule,
It has low compatibility with lipophilic binders and gradually migrates or phase separates from the binder. The present invention will be described in detail below. The photosensitive printing plate produced according to the present invention contains at least one of the above-mentioned compounds in the photosensitive layer. Since this compound has low compatibility with the photosensitive substance and binder, which are the main components of the photosensitive layer, at least a part of it is deposited on the surface of the photosensitive layer due to migration or phase separation. It is presumed that the compound deposited on the surface forms irregularities and contributes to improving vacuum adhesion. Examples of the compound preferably used in the present invention include (a) an anhydride of alkenylsuccinic acid having an alkenyl group having 20 or more carbon atoms, (b) a half ester of the acid, and (c) a salt of a half ester of the acid. and (d) fatty acid ester of sorbitan can be cited as a typical example. Examples of anhydrides of alkenylsuccinic acid (a) having an alkenyl group having 20 or more carbon atoms, which is one of the compounds used to improve vacuum adhesion, include α-olefin and maleic anhydride obtained by low polymerization of ethylene. Examples include those obtained by reacting with an acid. Examples of α-olefins used as raw materials include mixtures of carbon atoms with a carbon number of 20 to 28 (manufactured by Mitsubishi Chemical Corporation, Dyalene 208, Dyalene is a registered trademark of Mitsubishi Kasei Corporation), mixtures of carbon atoms with a carbon number of 30 or more (manufactured by Mitsubishi Kasei Corporation, Diyaren 208 is a registered trademark of Mitsubishi Kasei Corporation); Examples include Dialen 30), manufactured by Co., Ltd. (b) Half ester of alkenylsuccinic acid can be obtained by half-esterifying the anhydride of alkenylsuccinic acid with alcohol such as methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, heptyl alcohol, lauryl alcohol, benzyl alcohol, etc. Here are the things you can get. Furthermore, (c) salts of half esters of alkenylsuccinic acid include calcium salts, magnesium salts,
Examples include lead salts, zinc salts, tin salts, strontium salts, and the like. (d) Various well-known fatty acid esters of sorbitan can be used, such as sorbitan stearate monoester, sorbitan stearate triester, sorbitan behenate monoester, and higher fatty acid esters having 12 to 30 carbon atoms. Mono-, di- or triesters of fatty acids are used. These compounds (hereinafter referred to as vacuum adhesion improving agents) are generally contained in the photosensitive layer in an amount of 0.05 to 10.0% by weight, preferably 0.1 to 5.0% by weight. In the present invention, a photosensitive printing plate basically has a photosensitive layer provided on a support, and is a photosensitive printing plate used for producing printing plates such as lithographic printing plates, letterpress printing plates, and intaglio printing plates. Includes sex print version. The support is a dimensionally stable plate-like material,
These include those conventionally used as supports for printed matter, and they can be suitably used in the present invention. Such supports include paper, paper laminated with plastics (e.g. polyethylene, polypropylene, polystyrene, etc.), e.g. aluminum (including aluminum alloys), zinc, iron,
Plates of metals such as steel, films of plastics such as cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc. Paper or plastic film on which metals such as those mentioned above are laminated or vapor-deposited are included. An appropriate support is selected from these supports depending on the type of printing plate. For example, in the case of a photosensitive lithographic printing plate, an aluminum plate, a composite sheet in which an aluminum sheet is bonded to a polyethylene terephthalate film as described in Japanese Patent Publication No. 18327/1984, etc. are preferable. In the case of a photosensitive letterpress printing plate, polyethylene terephthalate film, aluminum plate, iron plate, etc. are preferable. As the photosensitive material in the photosensitive layer provided on the support, any material can be used as long as its solubility or swellability in a developer changes before and after exposure. Particularly preferred are diazo compounds, such as photosensitive compositions consisting of diazo resin and silica (Japanese Patent Application Laid-Open No. 47-24404);
Poly(hydroxyethyl methacrylate) and diazo resin, diazo resin and soluble polyamide resin (U.S. Patent No. 3751257), azide photoreceptor and epoxy resin (U.S. Patent No. 2852379), azide photoreceptor, diazo resin, etc., with polyvinyl cinnamate Photosensitive resins that have unsaturated double bonds in their molecules and become insolubilized by dimerization upon irradiation with actinic rays, such as British Patent No. 843543 and British Patent No. 966297.
derivatives of polyvinyl cinnamate described in the specifications of U.S. Pat. No. 2,725,372, prepolymers of diallyl phthalate as described in U.S. Pat. Ethylenically unsaturated compounds that have a double bond and cause a polymerization reaction upon irradiation with actinic rays, such as unsaturated esters of polyols such as those described in Japanese Patent Publication No. 35-8495, such as ethylene glycol di( meth)acrylate, diethylene glycol di(meth)acrylate, glycerol di(meth)acrylate, glycerol tri(meth)acrylate, 1,4-cyclohexanediol(meth)acrylate,
1,4-benzenediol di(meth)acrylate, pentaerythritol tetra(meth)acrylate, 1,3-propylene glycol di(meth)acrylate, pento-1,5-diol-
A photosensitive composition of di-methacrylate, pentaerythritol tri(meth)acrylate, bisacrylate and methacrylate of polyethylene glycol with a molecular weight of 50 to 500, etc. as a negative working type photosensitive composition that becomes insoluble by the action of actinic rays. Useful. US Patent No.
3635709, 3061430, and 3061120, 0-diazooxide photosensitive materials, phosphotungstates of diazo resins (Japanese Patent Publication No. 39-7663), yellow blood salts of diazo resins (US Pat. No. 3,113,023) and diazo resin and polyvinyl-H
Photosensitive compositions made of -phthalate (Japanese Patent Application No. 18812/1972) are useful as positive working type photosensitive materials. Also, U.S. Patent No. 3,081,168,
Also useful are photosensitive compositions containing linear polyamides and monomers having addition-polymerizable unsaturated bonds, such as those described in Japanese Patent Nos. 3486903, 3512971, and 3615629. Therefore, the present invention exhibits particularly excellent effects in positive-working PS lithographic plates containing an O-diazooxide-based photosensitive material in the photosensitive layer. The production of the photosensitive printing plate according to the present invention involves incorporating the vacuum adhesion improving agent into a photosensitive liquid, applying the photosensitive liquid onto a support, and drying it to migrate the vacuum adhesion improving agent from the photosensitive layer. Once the phase separation is carried out and at least a portion thereof is deposited on the surface of the printing plate, the other steps can be carried out according to conventional methods. For example, it can be produced by dissolving a photosensitive substance, the vacuum adhesion improving agent, and, if necessary, a binder and other auxiliary agents in a solvent, and then applying the resulting photosensitive liquid onto a support and drying it. The solvent for preparing the photosensitive solution is preferably selected from those that dissolve both the photosensitive substance and the vacuum adhesion improver, but usually includes acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, 1-4-dioxane, and methanol. , ethanol, benzene, toluene, xylene, trichlene, N-methylpyrrolidone, dimethylformamide, ethylene glycol, monomethyl ether,
Acetate ester of ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether -4-
selected from methoxy-4-methylpentanone-2. The concentration of the photosensitive material containing the photosensitive substance, binder, etc. in the photosensitive solution varies depending on the coating method, but is usually 1 to 15% by weight. In the present invention, vacuum adhesion is improved by depositing a vacuum adhesion improving agent on the surface of the photosensitive printing plate to form irregularities on the surface, as described above. The degree of this unevenness is proportional to vacuum adhesion, but at the same time is inversely proportional to plate-making performance such as resolution and image reproducibility. That is, as the unevenness increases, the vacuum adhesion improves, but on the other hand, the plate-making performance tends to deteriorate.
From the above, the degree of surface unevenness must be selected within a range that satisfies vacuum adhesion and plate-making performance. The degree of this unevenness can be adjusted by the combination of the photosensitive material and the vacuum adhesion improver and the amount of the vacuum adhesion improver added. This can also be achieved by changing the method of applying the photosensitive liquid onto the support and the subsequent drying method, and is particularly influenced by the drying conditions. That is, when the drying speed is increased, the amount of the vacuum adhesion improving agent deposited on the surface of the photosensitive printing plate is reduced, and the unevenness of the surface is reduced. On the other hand, if the drying rate is slowed down, precipitation will increase and the surface irregularities will become larger. From the above, in order to produce a printing plate with a constant surface roughness, it is necessary to select the type and amount of the vacuum adhesion improver in accordance with the coating and drying conditions to be used. In other words, in mass production such as PS plates, it is necessary to increase the drying speed to improve productivity.
In that case, it is necessary to use and/or increase the amount of a vacuum adhesion improver that tends to precipitate. Furthermore, when each user performs whirler coating, the drying speed is generally slower than the above, so it is necessary to use a vacuum adhesion improver that does not easily precipitate and/or to reduce the amount added. The present invention has been described in detail above, and the photosensitive printing plate obtained by the present invention has excellent vacuum adhesion and also shows good results in dot reduction in halftone dot reproducibility. Furthermore, such photosensitive printing plates can be manufactured by a simple method. Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. [Synthesis of vacuum adhesion improving agent] Synthesis example 1 Dialene 30 (manufactured by Mitsubishi Chemical Corporation, carbon number 30 or more,
Further, 67 g of α-olefin having an average carbon number of 46) and 98 g of maleic anhydride were charged into a four-necked flask, and the mixture was heated and stirred at 200 to 220° C. for 6 hours under a nitrogen atmosphere to obtain alkenylsuccinic anhydride. Synthesis Example 2 76.8g of the alkenylsuccinic anhydride obtained in Synthesis Example-1, 7.4g of n-butyl alcohol, and 100ml of xylene were placed in a 4-necked flask, heated and stirred at 100°C for 3 hours, and then 3.4g of calcium oxide was added. Ta.
Gradually raise the temperature until the xylene refluxes (140-150℃
%), and the reaction was continued while removing the water produced in the reaction from the system. Approximately 0.9ml after heating and stirring for 4 to 5 hours.
After the reaction water was distilled off, excess calcium oxide was leaked out while keeping it warm. The leaked xylene was removed by evaporation to obtain the calcium salt of alkenylsuccinic acid half ester. Examples 1 to 3 A 0.3 mm aluminum plate was electrolytically etched in a hydrochloric acid bath, then anodized in a sulfuric acid bath, and then subjected to hot water treatment to produce grained anodized aluminum plates. did. A solution with the following composition is applied to this aluminum plate using a whirler.
It was dried to provide a photosensitive layer. The amount of application is based on after drying.
It was 2.5g/ ^m2 . Metacresol-formaldehyde novolac resin 5g 1,2-naphthoquinonediazide-sulfonic acid ester of metacresol-formaldehyde novolac resin 1g Vacuum adhesion improver (type and amount added are shown in Table 1) Ethylene glycol monomethyl ether 80g For the photosensitive printing plate thus obtained, the time required to bring the lithium film and the printing plate into close contact was measured using the vacuum contact method, and the results are shown in Table 1. The following method was adopted as the vacuum contact method. That is, 20% made with Sakura OL-100E film.
A lithographic film (500 x 700 mm) having a halftone image and a photosensitive printing plate (800 x 1003 mm) were vacuum-adhered using a horizontal vacuum printing frame KD-PI model manufactured by Kamo Electric Laboratory.

[Table] When these photosensitive printing plates were exposed to light and developed, positive images were obtained as in the original image, regardless of whether or not a vacuum adhesion improver was used. That is, no adverse effect of the vacuum adhesion improving agent on the plate-making performance was observed. An example of a comparative experiment is shown below. Application example 1 (1) Manufacture of photosensitive lithographic printing plate A 0.3 mm aluminum plate was prepared in advance in a 1.5% hydrochloric acid electrolyte aqueous solution at 25°C, 80 A/dm ² , and treatment time 20
After electrolytic roughening under conditions of 20% sulfuric acid bath, 25
C., 6 A/dm ² and a treatment time of 30 seconds, and this was used for a comparison experiment. First, the above-mentioned Example 1 was applied to one aluminum plate.
A photosensitive lithographic printing plate of the present invention 800×1003 mm (hereinafter abbreviated as A plate) was obtained by coating the photosensitive layer described in . On the other hand, on the anodized aluminum plate,
First, a photosensitive layer having the same composition as that described in Example 1 was coated, except that no vacuum adhesion improver was used. Next, a matte layer having the composition described in Example 1 of JP-A-51-111102 was applied thereon.
A photosensitive planographic printing plate 800×1003 mm (hereinafter abbreviated as B plate) was obtained. (2) Vacuum adhesion time Apply lith film (500×
700 mm) and measured the time required for vacuum adhesion, good adhesion was achieved within about 40 seconds in both cases. (3) Developability The above A and B versions were developed using a developer mainly containing sodium silicate (SDP-1, 1:6 diluted solution).
The samples were developed using an automatic processor and the development efficiency was compared. The A plate could be processed without problems up to about 3 m ² per developer, but the B plate suffered from poor development (non-image areas remained) after processing about 1 m ² . At that time, matting agent precipitation (filter clogging) was observed on the filter of the developing device.

Claims (1)

[Claims] 1. In a method for producing a photosensitive printing plate with improved vacuum adhesion by providing a photosensitive layer on a support, the photosensitive liquid for forming the photosensitive layer has compatibility with the photosensitive substance and the binder. By coating the photosensitive liquid on a support and drying it, the compound is caused to migrate or phase separate from the photosensitive layer, and its molecule contains at least one compound having a polar group and a non-polar group in its molecule. A method for producing a photosensitive printing plate, comprising depositing at least a portion on the surface of the photosensitive printing plate.