JP2010134223A - Photosensitive resin composition for water developable typographical printing, and photosensitive resin precursor for water developable typographic printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition for water developable typographic printing, which can solve in-curling by a photosensitive resin itself for obtaining high-performance printing plate; and to provide a photosensitive resin precursor for water developable typographic printing. <P>SOLUTION: The photosensitive resin composition for typographic printing comprises at least a soluble polymer compound, a photopolymerizable compound, and a photopolymerization initiator. In the photosensitive resin composition, the soluble polymer compound is a water-soluble or water-dispersible polyamide containing 6-nylon as a constitutional component, and a content of ε-caprolactam in the photosensitive resin composition is 2 mass% or lower. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photosensitive resin composition for water-developable letterpress printing and a photosensitive resin original plate for letterpress printing obtained using the same.

  Usually, as a photosensitive resin relief plate composition used for a printing plate, generally contains a soluble polymer compound, a photopolymerizable unsaturated compound and a photopolymerization initiator as essential components, and if necessary, a stabilizer, a plasticizer Etc. are blended.

Conventionally, the photosensitive resin composition layer is irradiated with actinic rays through a negative film (or positive film) having a transparent image mass part to cure the exposed mass part of the photosensitive layer, and then the unexposed mass part of the photosensitive layer. It is widely known that a relief plate for printing is prepared by a plate making process in which the solvent is removed by dissolution with an appropriate solvent, followed by drying and post-exposure.
As the photosensitive resin composition, those using soluble polyamide, polyether urea urethane, fully saponified or partially partially saponified polyvinyl acetate as a soluble polymer have been proposed, and soluble polyamide or polyether urea urethane is used. The photosensitive relief printing composition is particularly preferably used because of its excellent wear resistance. In the photosensitive resin convex original plate using these photosensitive resin letterpress compositions, the photosensitive resin convex original plate (Patent Document 1, Patent Document 2) in which the photosensitive resin layer is made highly repulsive to improve printability is high speed. The printability is improved.

Recently, users' requests for photosensitive resin convex masters have progressed in the direction of reproducing finer patterns, and even for the minimum highlights used for photographic printing etc., printed matter of 5% or less of 200 lines is smooth. It is required to reproduce.
As a conventional technique corresponding to the requirement of fine highlight halftone dot printability, a photosensitive resin convex original plate in which image reproducibility is improved by forming a multilayer structure having different light transmittances of the photosensitive resin layer (Patent Document 3). ), A photosensitive resin convex master plate (Patent Document 4) whose relief shape is sharpened by multilayering of the photosensitive resin layer (Patent Document 4), etc., and a highlight halftone dot of 5% to 1% of the highlight halftone of the printed matter A photosensitive resin convex master capable of satisfying the reproducibility of printed matter has been obtained.
As described above, the fine image reproducibility of the photosensitive resin original plate for letterpress printing has been greatly improved, but a large problem of inlay remains as a laminate of the letterpress printing plate.
In other words, the printing plate obtained from the printing original plate is used by being affixed to a plate cylinder or the like with a double-sided tape. However, when the printing plate is installed, the edge of the solid portion is raised. For this reason, in order to correct the lifted state, printing must be performed at a high printing pressure, and as a result, a fine image becomes very large due to the deformation due to the pressure.
For printing plate inlays, improvements to reduce incurl have been studied, such as increasing the rigidity of the support and providing a cushion layer on the support, but this is not satisfactory and depends on the photosensitive resin itself. A photosensitive resin original plate for letterpress printing that solved the incurl was awaited.
Japanese Patent Laid-Open No. 04-97154 JP 05-11447 A JP 2002-23349 A Japanese Patent Laid-Open No. 06-313966

  The present invention was devised in view of the current state of the prior art, and its purpose is to provide a photosensitive resin composition for letterpress printing and a relief printing in which incurling is solved by the photosensitive resin itself in order to obtain a high-performance printing plate. It is to provide a photosensitive resin original plate.

  As a result of intensive studies on the composition of a resin composition suitable for achieving the above object, the present inventors have completed the present invention. That is, the present invention relates to (1) a photosensitive resin composition for letterpress printing containing at least a soluble polymer compound, a photopolymerizable compound and a photopolymerizable initiator, wherein the soluble polymer compound comprises 6-nylon. A water-soluble or water-dispersible copolymer polyamide, and a photosensitive resin composition for water-developable letterpress printing, wherein the content of ε-caprolactam in the photosensitive resin composition is 2% by mass or less (2) The total amount of ε-caprolactam and residual solvent in the photosensitive resin composition is 4% by mass or less, and the residual solvent is alcohol or / and water. Water-developable photosensitive resin composition for letterpress printing, (3) Water-developable photosensitive resin original plate for letterpress printing, obtained from the photosensitive resin composition for letterpress printing of (1) or (2) It is.

  The photosensitive resin composition for letterpress printing in which the incurl of the present invention has been solved and the photosensitive resin original plate for letterpress printing obtained therefrom are printed products of a highlight halftone printing plate of 1% to 5% obtained by the plate making process. It has extremely excellent printing original plate performance that can greatly improve the reproducibility of the image, and contributes greatly to the industry.

The soluble polymer compound used in the present invention is a water-soluble or water-dispersible polyamide containing 6-nylon as a constituent component, and is a copolymer polyamide containing 6-nylon and a hydrophilic component. The polyamide of the present invention may contain an ester bond or a urethane bond in addition to the amide bond.
Specific examples of the copolymerized polyamide include a photosensitive resin composition (Patent Document 1) using a polyamide having a sulfonic acid group or a sulfonate group in the side chain as a soluble polymer compound, and a copolymerized polyamide containing a polyethylene glycol segment. Photosensitive resin composition (Patent Document 2) as a polymer compound, photosensitive resin composition (Patent Document 3) as a soluble polymer compound containing a copolymerized polyesteramide containing a polyethylene glycol segment, and a basic nitrogen atom Examples thereof include a photosensitive resin composition containing polyamide as a soluble polymer compound (Patent Document 4).
JP-A-48-72250 JP-A-55-74537 JP 58-117537 A Among the polyamides, basic nitrogen-containing copolymer nylon and polyether-containing polyamide are preferable.

In the present invention, it is necessary to control the content of ε-caprolactam in the photosensitive resin composition in order to reduce the incurl of the printing plate. As content rate of (epsilon) -caprolactam in the photosensitive resin composition, 2 mass% or less is preferable, More preferably, it is 1% or less. If the content of ε-caprolactam in the photosensitive resin composition exceeds 2% by mass, the incurl increases, which is not preferable.
In the present invention, the method for adjusting the content of ε-caprolactam in the photosensitive resin composition to 2% by mass or less includes a method in which the polymerization time is extended to advance the reaction of ε-caprolactam, or ε-caprolactam after polycondensation. There is a method of extracting with water or a solvent that can dissolve. As a specific method for extracting with water or a solvent, a method in which a strand is thinned at the time of casting in water after polymerization and sufficient time is taken, or a method of extracting with water or a solvent after being formed into chips is desirable.

Next, the residual solvent amount contained in the photosensitive resin composition of the present invention will be described.
In the present invention, in order to reduce the incurl property, the content of ε-caprolactam in the photosensitive resin composition is in a specific range, and the amount of residual solvent contained in the photosensitive resin composition is also in a specific range. Thus, an excellent photosensitive resin original plate with little incurling is obtained as a printing plate.
The ε-caprolactam present in the photosensitive resin composition must be contained within a specific range in order to cause volume shrinkage by being extracted into developing water during development. Surprisingly, by making the residual solvent contained in the photosensitive resin composition within a specific range, it is possible to obtain a printing plate having excellent flatness with very little incurl.

  In the present invention, in order to obtain a printing plate with less incurl, the content of ε-caprolactam in the photosensitive resin composition is in a specific range, and the amount of residual solvent contained in the photosensitive resin composition is also in a specific range. The total amount of ε-caprolactam and / or residual solvent is preferably 4% by mass or less, more preferably 3% by mass or less. If the total amount exceeds 4% by mass, the curl degree exceeds 2 cm, which is not preferable from the viewpoint of wearability.

  As a method for setting the amount of residual solvent in the photosensitive resin composition within a specific range, it is sufficient to control the concentration time and temperature at the stage of concentrating the photosensitive resin composition solution. A low content can be achieved.

  In addition to the soluble polymer compound, the photopolymerizable unsaturated monomer, and the photopolymerizable initiator, the photosensitive resin composition may contain additives such as a stabilizer and a plasticizer as necessary. Examples of the stabilizer include hydroquinone, hydroquinone monomethyl ether, and 2,6-di-t-butyl-p-cresol, and these are preferably contained in the composition in an amount of about 0.001 to 5% by mass. . The plasticizer is added for the purpose of changing the physical properties of the photocured product. Examples thereof include low molecular plasticizers such as esters and amides, and oligomers such as polyesters, polyethers, and liquid rubbers. The plasticizer is contained in the composition in an amount of 0.1 to 20% by mass, preferably 5 to 15% by mass. Moreover, according to the product use obtained after exposure and image development, a well-known dye and pigment | dye can be added and the photosensitive resin composition can also be colored.

  The photosensitive resin composition of the present invention is a target product by any known method such as hot pressing, casting, melt extrusion, solution casting, etc. in addition to the melt molding method for obtaining a relief plate for printing. Can be formed into a desired shape.

  When obtaining a relief plate for printing, a molded product (raw plate) formed into a sheet can be used by being laminated on a support with or without a known adhesive. As the support, any material such as steel, aluminum, glass, a plastic film such as a polyester film, and a metal-deposited film can be used. When a sheet-like molded product (raw plate) is supplied as a laminate laminated on a support, a protective layer is further laminated in contact with the sheet-like molded product (raw plate). The protective layer is a film-like plastic, for example, a polyester film having a thickness of 1 to 3 μm coated with a non-sticky transparent polymer dispersed or dissolved in a developing solution. By contacting the protective layer having a thin polymer film with the sheet-like molded product (raw plate), the protection performed during the next exposure operation even when the surface-like property of the sheet-shaped molded product (raw plate) is strong. The layer can be easily peeled off.

  A photosensitive original plate consisting of such a composition alone or of this layer and a support is formed by closely adhering a negative film or a positive film having a transparent image portion on the photosensitive layer, and actinic rays from above. When the exposure is performed by irradiating, only the exposed portion is insolubilized and cured. The actinic ray is usually a light source such as a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, or a chemical lamp centered at a wavelength of 300 to 450 nm.

Subsequently, the unexposed portion is dissolved and removed with a suitable solvent, particularly neutral water in the present invention, to obtain a relief printing having a clear image portion. For this purpose, a spray developing device, a brush developing device or the like is used.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. The caprolactam content in the soluble polymer, the residual solvent amount in the photosensitive resin layer, and the curl degree are values measured by the following methods.
(1) Caprolactam content Polyamide resin is crushed, JIS standard sieve 24mesh passed 124mesh non-passed powder is collected, Soxhlet extracted with tetrahydrofuran for 3 hours, and caprolactam contained in the extract is quantified using a high performance liquid chromatograph. did. The measurement conditions are as follows.
High-performance liquid chromatograph: Waters 600E column: GL Science ODS-3 detector: Waters 484 Tunable Absorbance Detector Detection wavelength: 254 nm Injection volume: 10 μl Solvent: Methanol / water (20:20 (volume ratio))
Flow rate: 1 ml / min.
(2) Residual solvent content in photosensitive resin layer Moisture content: Moisture vaporizer (EV-6 manufactured by Hiranuma Sangyo Co., Ltd.) N ₂ 0.3 L / min automatic moisture measuring device (AQV- manufactured by Hiranuma Sangyo Co., Ltd.) Type 1) sample; 400 mg to 500 mg
Alcohol content: gas chromatograph (Yanamoto Seisakusho G-180 type) He 1.0 kg / cm ² column; Tenax-GC (manufactured by GL Sciences) column temperature 70 ° C. set sample; dissolved in an appropriate solvent for gas chromatographic analysis A sample is used. A suitable solvent that does not contain the measurement component is used. In the following examples, methanol was analyzed using ethanol as a solvent.
(3) Curing degree of printing plate Photosensitive on a support obtained by coating a polyurethane adhesive layer obtained from a polyester resin and an isocyanate compound on a polyethylene terephthalate film having a thickness of 250 μm to a film thickness of 20 μm by a known method. The printing original plate provided with the conductive resin layer was exposed for 10 minutes using a printer for A2 size (Mitsubishi Chemical Lamp) manufactured by JEOL Seiki Co., Ltd., and then cut to prepare a sample having a diameter of 10 cm. Next, using tap water as a developer, development is performed at 25 ° C. for 2 minutes using a brush-type washer (140 μmφ nylon brush, JW-A2-PD type manufactured by JEOL Ltd.) to obtain a fully exposed relief. did it. The obtained relief image having a diameter of 10 cm was stored at 20 ° C. and 32% RH for 7 days to prepare a sample for curl degree evaluation. The obtained evaluation sample was placed on an experimental bench having a horizontal plane, and the degree of incurl was measured. The degree of incurl was the highest position of the relief that warped up and deformed inward, and was defined as a height (cm) from the plane.

Example 1
6. 55.0 parts by mass of ε-caprolactam, 40.0 parts by mass of N, N′-bis (3-aminopropyl) piperazine and adipic acid nylon salt, 1,3-bisaminomethylcyclohexane and adipic acid nylon salt After the internal temperature reached 240 ° C., 5 parts by mass was maintained at 240 to 260 ° C. and melt polycondensed for 1 hour to obtain a basic nitrogen atom-containing copolymer polyamide.
Next, ε-caprolactam contained was extracted and removed using the obtained basic nitrogen atom-containing copolymer polyamide. In the extraction, polyamide was pulverized and treated for 60 minutes by extraction with a Soxhlet extractor using tetrahydrofuran as a solvent. The polyamide after the treatment contained 0.7% by mass of ε-caprolactam, which was greatly reduced as compared with 5.3% by mass before the treatment.

  55.0 parts by mass of the treated polyamide, 7.7 parts by mass of N-methyltoluenesulfonic acid amide, 0.02 parts by mass of 1,4-naphthoquinone, 50.0 parts of methanol and 10 parts by mass of water are heated with a stirrer. After mixing the polymer in a dissolution vessel at 60 ° C. for 2 hours to completely dissolve the polymer, 33.1 parts by mass of an acrylic acid adduct of trimethylolpropane triglycidyl ether, 3.1 parts by mass of methacrylic acid, hydroquinone monomethyl 0.1 part of ether and 1.0 part by weight of benzyldimethyl ketal were mixed and dissolved for 30 minutes. Next, the temperature was gradually raised, methanol and water were distilled off, and the mixture was concentrated until the temperature in the kettle reached 110 ° C. At this stage, a fluid and viscous photosensitive resin composition for the photosensitive resin layer was obtained.

Next, the obtained photosensitive composition was supplied so as to come into contact with a film having a polyester adhesive layer coated to a thickness of 20 μm on a polyethylene terephthalate film having a thickness of 250 μm, and a PVA layer having a thickness of 2 μm was coated as an anti-adhesive layer. A sheet-shaped photosensitive resin original plate having a total thickness of 1080 μm was formed using a laminator so as to cover with a polyethylene terephthalate film having a thickness of 100 μm.
After the photosensitive resin original plate is stored for 7 days or more, the 125 μm polyester film is peeled off, and the test negative film (gray scale negative film for sensitivity measurement and negative film for image reproducibility evaluation) is vacuum-adhered to an ultrahigh pressure mercury lamp. For 40 seconds. Next, with a brush-type washer (100 μmφ nylon brush, JW-A2-PD type produced by JEOL Ltd.), tap water is used as a developing solution and developed at 25 ° C. for 1 minute 45 seconds to obtain a relief image. It was. Furthermore, as a result of evaluating the relief obtained by hot air drying at 70 ° C. for 20 minutes and then post-exposure with an ultrahigh pressure mercury lamp for 30 seconds, the gray scale was 17 steps, 200 μm independent point, and 30 μm fine line was reproduced.
On the other hand, a relief image for measuring the curl degree was prepared according to the evaluation method, and the obtained 10 cm diameter relief image was stored at 20 ° C. and 32% RH for 7 days to prepare a curl degree evaluation sample. The obtained evaluation sample was placed on an experimental bench having a horizontal plane, and the degree of incurl was measured. The measured incurl degree is 0.8cm, which is an excellent incurl degree, and is mounted on a metal roll with a diameter of 10cm assuming the plate cylinder of a printing press using a double-sided polyester tape. A printing plate having was obtained.

Examples 2-5, 8
Polymerization was carried out in the same manner as in Example 1 to obtain a 6 nylon polyamide. Using the copolymer polyamide obtained by performing the extraction treatment of Table 1, the same components as in Example 1 other than the copolymer polyamide were dissolved and mixed in the same ratio to obtain a photosensitive resin composition, and the photosensitive resin A photosensitive resin printing original plate was prepared using the composition.
In Examples 2 to 3, the extraction conditions of ε-caprolactam were changed. In Example 4, the total amount of [caprolactam content + residual solvent content] was almost the same as in Example 1, and the ratio of ε-caprolactam content. A photosensitive resin composition having a high viscosity was obtained, and a photosensitive resin printing original plate was prepared using the photosensitive resin composition.
In Example 5, a copolymerized polyamide having a reduced amount of ε-caprolactam under polymerization conditions was used. Example 8 is a case of a photosensitive resin printing original plate produced by using a copolyamide having a low ε-caprolactam content and a total amount of [caprolactam content + residual solvent content] at an upper limit value.
Performance evaluation was performed using the obtained photosensitive resin printing original plate, and the result is shown in Table 1.

Examples 6-7
Polymerization was carried out in the same manner as in Example 1 with the polymer composition ratio (charge mass ratio) in Table 1 to obtain a 6 nylon copolymer polyamide. Using the polyamide obtained by performing the extraction treatment of Table 1, a photosensitive resin composition is obtained using the same raw materials as in Example 1 except for the polyamide, and a photosensitive resin printing original plate is prepared using the photosensitive resin composition. did. Performance evaluation was performed using the obtained photosensitive resin printing original plate, and the result is shown in Table 1.

Comparative Examples 1-4
In Comparative Example 1, Comparative Example 2 and Comparative Example 3, a photosensitive resin printing original plate was prepared in the same manner as in Example 1 without performing ε-caprolactam extraction treatment of the polymer in Example 1, Example 5 and Example 7. . Performance evaluation was performed using the obtained photosensitive resin printing original plate, and the result is shown in Table 1.
On the other hand, in Comparative Example 4, the same ε-caprolactam extraction treatment as in Example 1 was performed, but a photosensitive resin printing original plate having a high residual solvent amount ratio was prepared. Performance evaluation was performed using the obtained photosensitive resin printing original plate, and the result is shown in Table 1.

  From the evaluation results of Table 1, the curl degree is excellent when the content of ε-caprolactam is 2% by mass or less in the composition, and particularly the content of ε-caprolactam is 2% by mass or less and the amount of residual solvent. It is clear that the curl degree is particularly excellent when the total amount is 4% by mass or less.

  The photosensitive resin composition and the photosensitive resin original plate for letterpress printing of the present invention can produce a high-performance printing plate in which incurling has been solved by the photosensitive resin itself, and are extremely useful particularly in the field of seal printing.

Claims (3)

  In a photosensitive resin composition for letterpress printing comprising at least a soluble polymer compound, a photopolymerizable compound and a photopolymerizable initiator, the soluble polymer compound is a water-soluble or water-dispersible copolymer containing 6-nylon as a constituent component. A photosensitive resin composition for water-developable letterpress printing, which is a polymerized polyamide and has a content of ε-caprolactam in the photosensitive resin composition of 2% by mass or less.   The water-developable relief printing according to claim 1, wherein the total amount of ε-caprolactam and the residual solvent in the photosensitive resin composition is 4% by mass or less, and the residual solvent is alcohol or / and water. Photosensitive resin composition.   A photosensitive resin precursor for water-developable letterpress printing, obtained from the photosensitive resin composition for letterpress printing according to claim 1 or 2.