JPS6225109B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing printing plates for offset printing. More specifically, the present invention relates to a plate-making method in which electron beam curable ink is transferred using an offset printing machine and cured with electron beams. In recent years, the speed and efficiency of printing has been increasing, and there is a desire for faster and more efficient plate making in the printing process. Under these circumstances, for example, in rotary letterpress printing, efforts are being made to replace lead plates with resin plates in order to improve the working environment and reduce pollution. However, the production of resin plates has a problem in that the cost is higher than that of lead plates. Therefore, an inexpensive plate that does not use lead is desired. In addition, there was a tendency to want to achieve the printing effects of offset printing, and the printing that had been done with rotary letterpress began to be replaced with offset printing, and a new method of manufacturing printing plates for offset printing was created. It is also desired. Conventionally, there are the following methods for making printing plates for offset printing. (1) Direct image transfer method, (2) Photochemical transfer method, (3) Photodirect method, (4) Electrophotographic method, etc., allow plate making to be performed easily and quickly, and the number of sheets to be passed through is too large. This method is used when high printing effects are not required. In addition, (5) photolithography is a method used when a large number of sheets are to be printed and high-quality printed matter is required, and plate making tends to be complicated, and the plate has poor printing durability and reproduction accuracy. It is needed. The plate-making method for offset printing plates that is currently widely used is the lithography method, in which a photosensitive layer is provided on a metal or plastic substrate, a negative or positive film is adhered to it, and then it is baked and developed. This includes egg white version,
There are various types such as PS plate, Wipon plate, flat intaglio plate, and multilayer metal plate. Among these plates, the egg white plate and the Wipon plate have some drawbacks in printing durability, and the other plates have a printing durability that can withstand over 100,000 sheets, especially when used with multilayer metal plates. The plate is known to have a printing durability that can withstand over 500,000 sheets. However, even with multilayer metal plates, there are concerns about problems such as pollution treatment, and the use of PS plates is becoming more preferred. However, PS plates have inferior printing durability compared to multilayer metal plates, so when printing in large quantities, it is necessary to make many plates, and as a result, plate making costs are higher than resin plates. It was hot. As a method for solving the above-mentioned problems, a method of manufacturing a printing plate has recently been proposed in which an ink having ink receptivity after curing and fixation is transferred onto a rough aluminum surface by an offset printing method. The above method does not require new equipment,
It is expected that printing plates can be produced quickly, easily, and at low cost without causing any pollution or occupational hygiene problems. However, the ink transferred by this offset printing method must not only have the same properties as ordinary printing inks, but also have sufficient properties to become the oil-sensitive part of the plate when hardened and fixed. be done. That is, the ink to be transferred by the offset printing method must have the following properties. 1. Good adhesion to substrates including rough metal surfaces such as aluminum and chrome plating. 2. Good suitability for offset printing, especially good dot reproducibility. 3. The ink receptivity should be good after curing and fixation. 4. The printing durability of the part after curing and fixing should be good. 5 After being transferred using a printing machine, it rapidly hardens and becomes fixed. Ultraviolet curing ink is known as one of the inks for manufacturing printing plates that relatively satisfy the above properties, and is disclosed in Japanese Patent Application Laid-Open Nos. 53-100005 and 1973.
-53003 and JP-A-54-53004 disclose a technique using a commercially available ultraviolet curable ink. However, according to the inventor's studies, the above-mentioned commercially available UV-curable ink cannot produce printing plates that are sufficient for practical use in terms of printing durability, dot reproducibility, etc.; It was necessary to consider ink. In addition, UV-curable inks require a photopolymerization initiator due to their curing mechanism, and because UV light transmittance is insufficient, low-molecular-weight photopolymerization initiators remain in the film after curing. In addition, there are problems such as the ink embedded in the rough surface of the substrate is not cured sufficiently, and therefore, the resulting printing plate is difficult to use when printing on paper with a lot of paper dust, such as newspaper printing, for a long time. It has been found that the printing press has the disadvantage that it does not have sufficient printing durability required for printing. Therefore, the inventor of the present invention conducted intensive research and produced an electron beam curable printing ink containing a curable resin made by esterifying acrylic acid and/or methacrylic acid, and transferred it onto a substrate using an offset printing method. When the ink printing film was then cured by electron beam irradiation, it was possible to obtain an extremely excellent printing plate for offset printing. That is, the present invention uses an offset printing machine to print from an original onto a substrate, (A) 30 to 80 parts by weight of a curable resin, (B) 5 to 50 parts by weight of a reactive diluent, and (C) a thermal polymerization inhibitor. Transfer an electron beam curable ink consisting of 0 to 1 part by weight, and (D) 0 to 60 parts by weight of pigment, and then irradiate the transferred electron beam curable ink with an electron beam to harden and fix it on the substrate. This is a method for producing a printing plate for offset printing, which is characterized by the following. In the present invention, a substrate similar to that used in the production of general offset printing plates can be used, but the printing ink transferred by the offset printing method firmly adheres to the substrate, which increases the durability. The surface of the base plate is made of aluminum, zinc, or chrome plating with extremely fine grains to increase printing power and improve water retention during printing after printing. Preferably, it is made of a plate or the like. In addition, as for the graining method, use a polishing ball of an appropriate size (glass, ceramic, steel, etc.) and an abrasive (garnet, carborundum, alundum, etc.)
Also, the beading method uses water and vibration to make small scratches on the metal surface, the method of blowing wet abrasive onto the metal surface with compressed air, the brushing method, anodizing method, boehmite treatment, and combinations of these methods. However, in order to improve water retention during printing, adhesion to printing ink transferred by offset printing, and printing durability, further anode treatment is required after mechanical polishing such as the doweling method or brazi method. It is preferable to use oxidation or boehmite treatment. More preferably, if an aluminum plate roughened by electrolytic polishing is further anodized, a printing plate with easy water adjustment and excellent reproducibility and printing durability can be obtained. In the present invention, an offset printing machine is used to transfer electron beam curable printing ink from an original plate onto a substrate. A resin plate, a waterless planographic plate whose non-image areas are coated with a silicone compound, etc. are used. Although the offset printing machine is not particularly limited, it is preferable to use a metal plate printing machine or an offset printing proofing machine. In the present invention, the electron beam curable printing ink transferred onto the substrate with an offset printing machine is made of (A) curable resin 30~
(B) 5 to 50 parts by weight of a reactive diluent, (C) 0 to 1 part by weight of a thermal polymerization inhibitor, and (D) 60 parts by weight or less of a pigment if necessary. Preferable for achieving the purpose of the invention. Among the curable resins related to the present invention, (a) general formula

[Formula] (wherein R represents an organic residue having 1 to 3 carbon atoms, and n represents an integer of 0 or 1 to 6) and/or these 5-membered ring compounds having a double bond. Alder reaction product and
(b) Acrylic acid is added to a resin having a hydroxyl group obtained by reacting a compound having both a polymerizable double bond and a hydroxyl group in the same molecule, or a resin having a hydroxyl group obtained by hydrogenating the resin as necessary. as well as/
Alternatively, the curable resin obtained by esterifying methacrylic acid is composed of cyclopentadiene, dicyclopentadiene, tricyclopentadiene, tetracyclopentadiene, and lower alkyl substituted products thereof having 1 to 3 carbon atoms as component (a). one or more selected from the group consisting of one or more selected from the group consisting of: (b) component selected from the group consisting of (meth)allyl alcohol, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, butenediol, etc. One or more selected components are mixed in the presence of a radical polymerization catalyst at a molar ratio of component (a)/component (b) of 30/70 to 95/5, preferably 40/60 to 80/20. Alternatively, without a catalyst, if desired, in the presence of a solvent such as xylene, heat the reaction at 150 to 350°C to obtain a resin having a hydroxyl group, and if necessary, hydrogenate the resin having a hydroxyl group to obtain a large It is obtained by preparing a so-called resinous polyol whose portion is occupied by a diol having a molecular weight of 300 to 500, and then subjecting it to an esterification reaction with acrylic acid and/or methacrylic acid. In the above process, the hydrogenation conditions must be carefully selected, and it is preferable to use a noble metal catalyst such as platinum or palladium.
It is preferable to carry out the hydrogenation under the condition of 100 Kg/cm ² without reducing the amount of hydroxyl groups. The degree of hydrogenation is usually 40% or more, preferably 60% or more of the carbon-carbon double bonds of the resin (resinous polyol) having hydroxyl groups, to obtain an extremely clear hue and stability after electron beam curing. A product that gives a good cured film can be obtained. Further, the reaction between the resin having a hydroxyl group and acrylic acid and/or methacrylic acid is carried out under normal esterification reaction conditions in the presence of a catalyst or without a catalyst. At this time, it is preferable to react acrylic acid and/or methacrylic acid in an amount of 0.5 to 1 molar equivalent per hydroxyl group 1 of the resin having a hydroxyl group. Among the curable resins according to the present invention, acrylates and/or methacrylates obtained by esterifying polyol with acrylic acid and/or methacrylic acid [these are referred to as (meth)acrylates]. ] is obtained by esterifying polyols such as various glycols, trimethylolpropane, pentaerythritol, dipentaerythritol, and polypentaerythritol with acrylic acid and/or methacrylic acid. However, (meth)acrylate obtained by esterifying these polyols with acrylic acid and/or methacrylic acid alone does not have the necessary viscosity and flow characteristics as a printing ink, as well as the flexibility and toughness of the film after electron beam curing. unsaturated polyester resins, conjugated drying oils, epoxy resins, urea-formaldehyde resins, allylsulfonamide-formaldehyde resins, cetyl vinyl ether, and diallyl phthalate prepolymers used for printing inks. or mixtures thereof with the above (meth)acrylates 30
It is desirable to add 70 to 30 parts by weight to ~70 parts by weight to compensate for these drawbacks. Among the curable resins related to the present invention, polyester resin-based acrylates and/or methacrylates are obtained by esterifying acrylic acid and/or methacrylic acid with modified alkyds, polyesters, etc., which have been used as vehicles for inks. It is something that can be done. In other words, oils or fatty acids have been modified for the purpose of adjusting viscosity, solubility, wettability to pigments, film flexibility, etc.
It is obtained by esterifying acrylic acid and/or methacrylic acid with an alkyd resin containing excess OH groups or a polyester resin containing excess OH groups. Among the curable resins related to the present invention, (meth)acrylates obtained by esterifying acrylic acid and/or methacrylic acid with a compound having an epoxy group are, for example, epoxy resins consisting of bisphenol A/epichlorohydrin and epoxidized linseed oil. It is obtained by esterifying acrylic acid and/or methacrylic acid, and is characterized by its excellent curing properties and the ability to form a very tough film with excellent solvent resistance. Among the curable resins related to the present invention, the urethane-modified acrylic resin and/or methacrylic resin is prepared by combining an OH-excess alkyd or a polyester with a hydroxyl group-containing acrylic ester and/or a hydroxyl group-containing methacrylic ester, toluene diisocyanate, It is obtained by bonding with a diisocyanate such as isophorone diisocyanate. In the present invention, vinyl compounds are preferred as the reactive diluent, and (meth)acrylic acid derivatives are preferred in view of the requirements for reactivity, solubility, and low viscosity. Examples of such acrylic acid derivatives include trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol(meth)acrylate, 1,4-butanediol(meth)acrylate, and 1,6-hexane. Acrylic acid or methacrylic acid is esterified with diol (meth)acrylate, alkyl (meth)acrylate (alkyl group having 1 to 18 carbon atoms), monohydric phenol or polyhydric phenol with alkylene oxide added to the hydroxyl group. Crosslinkable monomers such as styrene, allyl alcohol ester, and glycidyl (meth)acrylate can be used. In the present invention, the pigment is not particularly limited, and organic pigments and inorganic pigments used in offset inks can be used. Although it is not always necessary to add pigment, it is necessary to check and correct the condition when it is transferred to the substrate, and to check the rheological properties of the ink so that the original image can be transferred with good reproducibility using an offset printing machine. Used for adjustment. In the present invention, polymerization inhibitors that are effective for acrylic and/or methacrylic compounds can be used as they are, but hydroquinone and its derivatives, tetramethylthiuram disulfide, N-nitrosophenylhydroxyamine, etc. Particularly effective are aluminum salts. In producing the electron beam curable printing ink according to the present invention, (1) the curable resin is (2) made into a varnish with a reactive diluent, (3) a thermal polymerization inhibitor is added, and (4) as necessary. Disperse and knead together with pigment using a three-roll mill or the like. As the dispersion method, a so-called flushing method may be used depending on the case. Then, the tack value at 400rpm 30℃ is 5 to 20, and the flow value at 25℃ for 60 seconds.
It is made by adjusting it to 15-20. It goes without saying that other organic solvents, fillers, additives, etc. can be added as necessary during the above operation. In the present invention, the above-mentioned electron beam curable printing ink is rapidly cured on the substrate transferred by an offset printing machine by irradiation with an electron beam emitted from an electron beam generator called Electrocurtain (manufactured by Energy Science Co., Ltd.). As mentioned above, the penetrating power of the electron beam is strong, so the solidification and curing progresses much more rapidly than when irradiating ultraviolet rays using ultraviolet curable ink, and it exhibits extremely good adhesion to the substrate. Unlike ultraviolet curable ink, it does not contain a low molecular weight photopolymerization initiator, so when printing using the printing plate of the present invention, the printing process starts from the cured film of the electron beam curable ink, which is the image area. Since there are no components that can be extracted by the ink used in the printing process, combined with the sufficient effect that the curing described above extends deep into the interior, extremely excellent printing durability is achieved. Further, the hardened and fixed portion has sufficient affinity for ink. That is, a printing plate is produced that provides printed matter with good ink receptivity to general oil-based printing inks and general ultraviolet-curable printing inks as images, and excellent reproducibility of the original plate. In addition, in offset rotary printing where printing durability is strongly required, a printing plate having printing durability comparable to that of a multilayer metal plate is produced. According to the invention, a large number of offset printing plates can therefore be manufactured very easily and inexpensively by the offset printing method. The following is a description using comparative examples and examples.
(In the examples, parts indicate parts by weight.) Comparative Example 1 132 parts of dicyclopentadiene with a purity of 97%, 58 parts of allyl alcohol, and 110 parts of commercially available mixed xylene were charged into an autoclave equipped with a stirrer, and the temperature was 260.
The reaction was carried out at ℃ for 5 hours. After the reaction is complete, the autoclave is cooled and the contents are distilled to remove unreacted monomers and
Removal of the low polymer and xylene yielded 152 parts of resin ()-1. This resin ()-1
Dissolve 100 parts in commercially available mixed xylene, add 1 part of palladium carbon with a palladium concentration of 5% (5% Pdc standard product manufactured by Engelhard Japan), and apply hydrogen pressure.
A hydrogenation reaction was carried out at 30 Kg/cm ³ at 150° C. for 1 hour, and the solvent was distilled off to obtain a water-added resin ()-1. The properties of Resin ()-1 and Resin ()-1 are as follows.

[Table] Next, 80 parts of resin ()-1, 20 parts of acrylic acid,
1.0 part of para-toluene sulfonic acid and 0.1 part of hydroquinone were added to a cooler with a side arm and a stirrer 4.
Pour into a neck flask and heat at 100℃ for 12 hours under reflux of benzene/methyl isobruketone (MIBK) mixed solvent.
After reacting for hours, benzene and MIBK were distilled off at 120°C to obtain resin (A)-1. Resin (A)-2 was also obtained by reacting Resin ()-1 with methacrylic acid in the same manner as Resin ()-1. Next, the obtained resin-
Varnish A and Varnish B were prepared by dissolving 70 parts each of 1 and (A)-2 in 30 parts of trimethylolpropane triacrylate. Comparative example 2 Epicote 828 (epoxy resin manufactured by Shell Oil Co., Ltd.)
71.7 parts, acrylic acid 28.3 parts, hydroquinone 0.1
1 part and 0.1 part of triethylenediamine were placed in a four-necked flask equipped with a reflux tube and a stirrer, and reacted at 90 to 110°C for 15 to 20 hours while blowing air. When the acid value reached 1 or less, it was pumped out. This is called varnish C. Comparative Example 3 20 parts of oleic acid and 47 parts of trimethylolpropane are reacted in a four-necked flask under a carbon dioxide gas stream at 240°C until the acid value reaches 5 or less. Then phthalic anhydride
Add 33 parts and react at the same temperature to obtain an alkyd resin with an acid value of 5 or less and a hydroxyl equivalent of 180. Next, 71.5 parts of this alkyd resin and 10.0 parts of benzene were charged into a four-neck flask equipped with a reflux device and a stirrer, heated to 90°C, and 85 parts of acrylic acid, 1.0 part of P-toluenesulfonic acid, and 0.1 part of hydroquinone were added. Drop it while blowing air at ~95℃, and gradually raise the temperature after dropping.
The reaction takes place at 100-120°C, and when the acid value reaches 5 or less, benzene is removed and pumped out. This is called varnish D. Varnishes A, B obtained in Comparative Examples 1, 2, and 3,
C and D are made into ink using three rolls according to the following formulation. The tack value mentioned below is 400r.p.
m. Value at 30℃, flow value means 60 seconds value at 25℃. Ink A Varnish A 48 parts Bisphenol A ethylene oxide adduct diacrylate 30 parts Carmine 6B (T) (red pigment manufactured by Toyo Ink KK)
13 parts methyl orthobenzoylacetophenone 6 parts methyl orthobenzoylacetophenone 6 parts P-dimethylaminoacetophenone 1 part 4,4'-bisdiethylaminoacetophenone 1 part organic bentonite 1 part Tack value 10.2 Flow value 15.6 Ink B Varnish B 36 parts dipentaerythritol hexaacrylate 28 parts Lionol Blue-KL (indigo pigment manufactured by Toyo Ink Manufacturing KK) 3 parts Hakuenka-O (extender pigment) 25 parts P-chlorothioxanthone 6 parts P-dimethylaminoacetophenone 2 parts Tack value 10.7 Flow value 16.1 Ink C Varnish A 42 parts Sorbitan triacrylate 34 parts Carmine 6B (T) (Red pigment manufactured by Toyo Ink Manufacturing KK) 14 parts Benzoin methyl ether 10 parts Organic bentonite 1 part Tack value 10.5 Flow value 15.8 Ink D Varnish C 50 parts Bisphenol A ethylene oxide adduct diacrylate 29 parts Carmine 6B (T) (Red pigment manufactured by Toyo Ink Manufacturing KK) 13 parts Methyl orthobenzoyl benzoate 6 parts P-dimethylaminoacetophenone 1 part 4.4' - Bisdiethylaminoacetophenone 1 part Tack value 10.5 Flow value 15.4 Ink E Varnish D 47 parts Dipentaerythritol hexaacrylate 32 parts Carmine 6B (T) (red pigment manufactured by Toyo Ink Manufacturing KK) 13 parts Benzyl 6 parts P-dimethylamino Acetophenone 1 part 4,4'-bisdiethylaminoacetophenone 1 part Tack value 10.7 Flow value 16.0 Inks A to E obtained in this way were used as master plates and PS plates (positive type) having an abstract pattern were used to print metal Printed on a 300 μ thick aluminum plate that was grained using an offset printing machine and then anodized, and the printed surface was placed 10 cm under a high-pressure mercury lamp H-2000L (manufactured by Toshiba KK) with an intensity of 80 W/cm. was irradiated for 10 seconds to produce printing plates A to E, respectively. Before irradiating ink A with a high-pressure mercury lamp, it was pretreated by heating at 180° C. for 5 minutes, and then irradiated with ultraviolet rays under the same conditions as above, resulting in printing plate F. In addition, printing plate G was obtained by further heat-treating printing plate A at 180° C. for 5 minutes after irradiating it with ultraviolet rays. Example 1 Varnish A obtained in Comparative Example 1 was used to form an ink according to the following formulation. Ink H Varnish A 52 parts Diacrylate of bisphenol A ethylene oxide adduct 33.9 parts Carmine 6B (T) (red pigment manufactured by Toyo Ink Manufacturing KK) 13 parts Organic bentonite 1 part N-nitrosophenylhydroxyamine aluminum salt 0.1 part Tack Value: 12.0 Flow value: 17.0 Ink H obtained in this way was grained by electrolytic polishing using a PS plate with an abstract pattern as an original plate, and then anodized. Printed on 300μ aluminum plate,
Immediately, the printing surface was cured by applying a dose of 5 megarad using an electron beam irradiation device manufactured by Energy Science Co., Ltd. to obtain a printing plate H. Example 2 Varnish B obtained in Comparative Example 1 was used to form an ink according to the following formulation. Ink I Varnish B 40 parts dipentaerythritrhexaacrylate 31.9 parts Lionnoble-KL (red pigment made by Toyo Ink Manufacturing KK) 3 parts Hakuenka-O (extender pigment) 25 parts Tetramethylthiuram disulfide 0.1 part Tack value 10.0 Flow Value 16.0 Ink I thus obtained was printed on a 300μ thick aluminum plate roughened by the ball-sharpening method using a flatbed offset printing machine for nameplate printing using a PS plate with an abstract pattern as an original plate. Immediately on the printing surface,
In the same manner as in Example 1, the plate was irradiated with an electron beam at a dose of 10 megarads to be cured to obtain a printing plate I. Example 3 60 parts of diallyl phthalate prepolymer was mixed with 39.5 parts of dipentaerythritol hexaacrylate and 0.5 parts of aluminum salt of N nitrosophenyl hydroxyamine, stirred and heated to 90°C for 1 hour to achieve a viscosity of 600 poise (25°C). Varnish E was obtained. This varnish was used to form ink according to the following formulation. Ink J Varnish E 60 parts Dipentaerythritol hexaacrylate 12 parts Mitsubishi Carbon Black MA8 (Carbon Black manufactured by Mitsubishi Kasei) 10 parts White Glossy Flower O (extender pigment) 18 parts Tack value 8.0 Flow value 17.0 Ink J thus obtained Using a silver master plate (Mitsubishi Paper Mills) as the original plate, an offset proofing machine was used to roughen the surface by brush polishing.
Plate J
And so. Example 4 Varnish D obtained in Comparative Example 3 was used to form an ink according to the following formulation. Ink K Varnish D 51 parts dipentaerythritol hexaacrylate
35.9 parts Carmine 6B (T) (Red pigment manufactured by Toyo Ink Manufacturing KK) 13 parts Hydroquinone 0.1 part Tack value 11.0 Flow value 17.0 Ink K thus obtained was used in an offset printing machine for printing on metal plates using a PS plate as a master plate. in,
After brush polishing and graining, printing was performed on an anodized aluminum plate having a thickness of 300 μm, and the printed surface was immediately cured by applying a dose of 20 megarads in the same manner as in Example 1 to obtain a printing plate K. Example 5 Varnish C obtained in Comparative Example 2 was used to form an ink according to the following formulation. Ink L Varnish C 54 parts Bisphenol A ethylene oxide adduct diacrylate 32.9 parts Carmine 6B (T) (red pigment manufactured by Toyo Ink Manufacturing KK) 13 parts Tetramethylthiuram sulfide 0.1 part Tack value 11.0 Flow value 16.0 In this way The obtained ink L was printed on a 300μ thick aluminum plate which had been roughened by the ball-sharpening method using a PS plate as an original plate using an offset automatic proofing machine, and then anodized, and then immediately injected onto the printed surface with 10Mg in the same manner as in Example 1.・The printing plate L is irradiated with a rad dose of electron beam and cured.
And so. Example 6 63.1 parts of pentaerythritol triacrylate is placed in a four-neck flask equipped with a reflux tube, maintained at 38 to 40°C, and 36.9 parts of toluene diisocyanate is added dropwise over 1 hour. When the residual isocyanate groups reach a constant level of around 8.7%, stop the reaction and start pumping. This is called acrylated isocyanate A. Then 20 parts of oleic acid, trimethylolpropane
47 parts were reacted in a four-necked flask with a stirrer at 240°C under a stream of carbon dioxide until the acid value reached 5 or less.
Thereafter, 33 parts of phthalic anhydride was added and reacted at the same temperature for 3 hours to obtain an alkyd with an acid value of 5 or less and a hydroxyl equivalent of 180. 90 parts of this alkyd with a hydroxyl equivalent of 180, 40 parts of trimethylolpropane triacrylate, and 0.1 part of hydroquinone were mixed and dissolved, 104.4 parts of the above acrylated isocyanate A was added, and the mixture was heated at 60 to 70°C for 7 to 70 minutes.
Let the reaction take place for 9 hours, and when the residual isocyanate group becomes 0.27 or less, pump it out. This is called varnish F.
This varnish was used to ink with the following formulation. Ink M Varnish F 47 parts diventaerythritol hexaacrylate
39.9 parts Carmine 6B (T) (red pigment manufactured by Toyo Ink Manufacturing KK) 13 parts N-nitrosophenylhydroxyamine aluminum salt 0.1 part Tack value 8.0 Flow value 17.0 Ink M thus obtained was used as a PS plate as an original plate. The thickness is then anodized after being grained by electrolytic polishing using an offset printing machine for printing metal plates.
It was printed on a 300μ aluminum plate, and the printed surface was immediately cured by applying a dose of 10 megarads in the same manner as in Example 1 to obtain a printing plate M. Next, varnish A~ obtained in Comparative Examples 1, 2, and 3
Printing plates A to G obtained by printing inks A to E made using D and curing with ultraviolet rays, and printing plates A to G obtained by printing inks H to M obtained in Examples 1 to 6 and irradiating them with electron beams. The results of a printing test using a BB type off-wheel printing machine manufactured by Mitsubishi Heavy Industries, Ltd. are shown below. Ink used in the test: WKN-HOP ink (Newspaper off-wheel ink manufactured by Toyo Ink Manufacturing KK) Paper: Newspaper (for off-wheel printing) (manufactured by Oji Paper) Printing durability: Printed with a BB type off-wheel printing machine manufactured by Mitsubishi Heavy Industries The results are shown by printing using A to G and H to M. Tint point reproducibility: The tint point percentage of the original plate is prepared in 6 steps at 10% intervals from 50% to 100%, and when printed on paper with a printing plate manufactured from the original plate having these six levels of tint point percentage, the printed matter is The tint percentage of the original plate corresponding to the stage where the tints are completely crushed.
expressed. In addition, the density at the 100% tint stage (solid area) is adjusted to a constant density,
In the case of 100%, no crushed dots are observed. Ink receptivity: When printing with the above WKN-HOP ink, the ink transfer of the printed matter is judged with the naked eye.

【table】

[Table] The printing plate obtained by printing on a rough plate using an offset printing method using an electron beam curable ink and curing by electron beam irradiation as described above can be printed on a rough plate using an offset printing method using an ultraviolet curable ink. print on top,
It has better printing durability and dot reproducibility than printing plates obtained by curing with ultraviolet irradiation.

Claims (1)

[Claims] 1. Using an offset printing machine from the original plate, (A) 30 to 80 parts by weight of a curable resin, (B) 5 to 50 parts by weight of a reactive diluent, and (C) Inhibition of thermal polymerization. Transfer an electron beam curable ink consisting of 0 to 1 part by weight of the agent and 0 to 60 parts by weight of the pigment (D), and then irradiate the transferred electron beam curable ink with an electron beam to harden and fix it on the substrate. A method for producing a printing plate for offset printing, characterized by: 2 (A) The curable resin is a resin having a hydroxyl group obtained by reacting the following (a) and (b), or a resin having a hydroxyl group obtained by hydrogenating the resin as necessary with acrylic acid and/or methacrylic acid. The manufacturing method according to claim 1, which is a (meth)acrylate obtained by ester-reacting an acid. (a) A 5-membered ring compound having a double bond represented by the general formula [formula] (wherein R represents an organic residue having 1 to 3 carbon atoms, and n represents 0 or an integer of 1 to 6) and/or their Diels-Alder reaction products. (b) A compound that has both a polymeric double bond and a hydroxyl group in the same molecule. 3 (A) Claim 1 in which the curable resin is a (meth)acrylate obtained by esterifying polyol with acrylic acid and/or methacrylic acid.
Manufacturing method described in section. 4 (A) Curing resin is 30 to 70 parts by weight of (meth)acrylate obtained by esterifying polyol with acrylic acid and/or methacrylic acid, unsaturated polyester, conjugated drying oil, epoxy resin, urea formaldehyde resin, allyl sulfonamide −
The manufacturing method according to claim 1, comprising 70 to 30 parts by weight of one or more selected from formamide resin and diallyl cetyl vinyl ether phthalate prepolymer. 5. The manufacturing method according to claim 1, wherein (A) the curable resin is a polyester resin-based acrylate and/or methacrylate. 6. The manufacturing method according to claim 1, wherein the curable resin (A) is a (meth)acrylate obtained by esterifying an epoxy group-containing compound with acrylic acid and/or methacrylic acid. 7. The manufacturing method according to claim 1, wherein (A) the curable resin is urethane-modified (meth)acrylate. 8. The manufacturing method according to claim 1, wherein the substrate is an aluminum plate that has been roughened by electrolytic polishing and then anodized.