JP2001228620A - Method for producing seamless photosensitive resin sleeve printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for enhancing solidness in printing by suppressing the roughening of the surface of a printing plate due to grinding in a method for obtaining a seamless printing plate using an IR laser and a method for forming an IR sensitive layer free from defects such as pinholes by enhancing the appliability of an IR sensitive coating fluid to a photosensitive resin. SOLUTION: In a method for obtaining a seamless printing plate by laminating a photosensitive resin layer on a sleeve, subjecting the layer to treatment for making it seamless, grinding the surface of the photosensitive resin to make the layer thoroughly seamless, disposing an IR sensitive layer, forming a mask by IR laser beam patterning, imagewise exposing the photosensitive resin layer through the mask and removing the unexposed part by development, a step for treating the surface of the photosensitive resin with a solvent which dissolves the resin is carried out between the grinding step and the step for disposing the IR sensitive layer. And the objective seamless photosensitive resin sleeve printing plate is produced in such a method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a seamless photosensitive resin sleeve printing plate used for flexographic printing.

[0002]

2. Description of the Related Art A conventional flexographic printing plate is disclosed in
As disclosed in JP-A-48744 and JP-A-5-134410, it is manufactured by using a photosensitive elastomer composition, exposing it to an image through a negative film, and washing out unexposed portions. The printing plate obtained is then pasted on the cylinder of the printing press and used for printing.However, it takes a long time to accurately position and paste the printing plate, and this work can be simplified. If so, a method of omitting it is desired.

In the case of printing a continuous and continuous pattern, the processing of the joint portion of the plate becomes a problem.
Conventionally, after wrapping a plate-shaped photosensitive resin around a sleeve, a similar liquid resin or a photosensitive elastomer composition dissolved in a solvent is used as a joint adhesive, and the swelling generated at the joint is scraped off. A method of making a seamless state has been adopted. However, such an operation requires skill and a long operation, and it is difficult to completely eliminate the seam by this method, and a method for easily obtaining a complete seamless plate has been desired.

[0004] As a method of making a sleeve-like plate having no seams, a plate-shaped photosensitive resin is wound around a sleeve, and then heated to a temperature higher than the softening temperature of the photosensitive resin to eliminate the seams. There has been proposed a method of obtaining a highly accurate seamless resin layer by polishing the surface of the photosensitive resin layer. However, this method has made it possible to obtain a seamless sleeve-shaped photosensitive resin layer having no seams. However, when a negative film is brought into close contact with a plate and exposed to form an image, the end of the negative film is exposed. Are overlapped, and that portion of the obtained printing plate becomes a stepped pattern, so that a seamless printing plate cannot be obtained.

[0005] Recently, as disclosed in JP-A-8-305030 and JP-A-9-166875, the surface of a photosensitive resin can be cut off with an infrared laser to block non-infrared rays. Is provided with an infrared-sensitive layer, a mask is formed by drawing with an infrared laser, and then image exposure through this mask, development,
Printing plates have been produced by drying. Utilizing this technology, it is possible to create a seamless printing plate by providing an infrared sensitive layer on a seamless photosensitive resin layer, forming a mask with an infrared laser, exposing the image, developing and drying. Attempted. However, since the surface of the photosensitive resin obtained by grinding is in a rather rough state, there is a problem that the solid crushing during printing is inferior. Also,
When the infrared-sensitive coating liquid is applied to the roughened surface, there is a problem that defects such as blurring and pinholes are easily generated in the coated infrared-sensitive layer.

[0006]

SUMMARY OF THE INVENTION The present invention provides a method for producing a seamless photosensitive sleeve printing plate which solves the above-mentioned problems of the prior art, that is, laminating a photosensitive resin layer on a sleeve, After removing the seam and completely removing the seam by polishing the photosensitive resin surface with a grind, an infrared-sensitive layer is provided, a mask is formed by infrared laser drawing, and image exposure through the mask is performed. In the method of obtaining a seamless printing plate by developing the exposed part, while reducing the roughness of the plate surface due to grinding, improving the solidity during printing, and improving the applicability of the infrared sensitive coating liquid to the photosensitive resin. An object of the present invention is to provide a method for obtaining an infrared-sensitive layer which is improved and free from defects such as blurring and pinholes.

[0007]

Means for Solving the Problems As a result of intensive studies on the above-mentioned problems, the present inventors have found that, in the above-mentioned method for obtaining a seamless printing plate, the photosensitive resin is dissolved between the grinding step and the step of providing an infrared-sensitive layer. The present inventors have found that the problem can be solved by providing a step of treating the photosensitive resin surface with a solvent having a property, and completed the present invention. That is, the present invention is a method of laminating a photosensitive resin on a sleeve, then performing a process of eliminating a seam, completely removing the seam by polishing the photosensitive resin surface by grinding, providing an infrared-sensitive layer, and providing an infrared laser. In a method of forming a mask by drawing, further exposing an image through the mask, and developing a non-exposed portion to obtain a seamless printing plate, the solubility of the photosensitive resin is reduced between the grinding step and the step of providing an infrared-sensitive layer. A process for treating the surface of a photosensitive resin with a solvent having the same.

Hereinafter, the present invention will be described in detail. The solvent used in the surface treatment of the photosensitive resin in the present invention has a solubility of the photosensitive resin, and means that when the solvent is applied to the photosensitive resin, the surface of the photosensitive resin becomes sticky. Specific examples of the solvent having solubility for the photosensitive resin include chlorine solvents such as tetrachloroethylene and 1,1,1-trichloroethane, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, and 2-butoxyethyl acetate described in EP 0355789. , Acetic acid 3,5,5-trimethylhexyl, octanoic acid ethyl ester and the like, and p-menthane, borneol, D- and L described in JP-A-62-160446.
Hydrogenated petroleum fractions described in JP-A-2-7056, terpenes described in JP-A-2-255385, phenyl acetate and phenyl propionate described in JP-A-4-018564, In addition to known developing solvents for flexographic printing plates such as benzyl acetate, 3-methoxybutyl acetate, and butyl diglycol acetate, toluene, ethyl acetate, methyl ethyl ketone and the like may be used alone or in combination.

Further, depending on the type of the solvent having the solubility of the photosensitive resin and the treatment method of the plate surface, traces of wiping may be left on the plate surface. Therefore, ethanol, isopropyl alcohol, acetone Solvents having no solubility for the photosensitive resin such as the above can be used by mixing in the range of 1 to 90% by weight. The surface treatment of the photosensitive resin in the present invention includes a method of wiping the surface of the photosensitive resin with a cloth impregnated with a solvent having solubility for the photosensitive resin, a method of immersing the sleeve in the solvent, a ring coater, a spray coater, and the like. By applying the solvent to the surface of the photosensitive resin.

When the surface treatment of the photosensitive resin is performed by wiping the cloth impregnated with the solvent, there is a possibility that a wiping mark may be left on the surface of the photosensitive resin. It is desirable to use a solvent having a low boiling point such as ethyl, toluene, methyl ethyl ketone, or a solvent having no solubility for the photosensitive resin. Surface treatment by a method of immersing the sleeve in a solvent or a method of applying a solvent to the photosensitive resin surface is useful because the treatment can be performed without touching the photosensitive resin surface. Solvents having the solubility of the photosensitive resin suitable for these methods include 3-methoxybutyl acetate, butyl diglycol acetate, diethylene glycol dimethyl ether, 3,5,5-acetic acid.
High boiling solvents such as trimethylhexyl, D- and L-limonene are preferred. Among these, alkoxypolyoxyalkylenyl esters such as 3-methoxybutyl acetate and butyl diglycol acetate are particularly preferable in terms of working environment because of their mild odor.

The sleeve used in the present invention may be any sleeve that is generally used as a flexographic printing sleeve, and examples thereof include a nickel sleeve, a plastic sleeve, and a glass fiber sleeve.
If necessary, a photosensitive resin layer can be laminated on a sleeve provided with a cushion layer such as urethane foam on the sleeve. Further, an adhesive may be interposed between the sleeve, the cushion material, the photosensitive resin layer, and the like, if necessary. As the photosensitive resin composition used in the present invention, those known for flexographic printing plates can be used.
Generally, a composition containing a binder polymer, at least one ethylenically unsaturated monomer, and a photoinitiator as main components is used. Further, additives such as a sensitizer, a thermal polymerization inhibitor, a plasticizer, and a coloring agent can be contained according to the characteristics required for the photosensitive resin layer.

As the binder polymer, for example, a thermoplastic elastomer obtained by polymerizing a monovinyl-substituted aromatic hydrocarbon monomer and a conjugated diene monomer is used. Monovinyl-substituted aromatic hydrocarbon monomers include:
Styrene, α-methylstyrene, p-methylstyrene,
Examples of the conjugated diene monomer include p-methoxystyrene and the like, and examples of the conjugated diene monomer include butadiene and isoprene. Specific examples include a styrene-butadiene-styrene block copolymer and a styrene-isoprene-styrene block copolymer.

The at least one ethylenically unsaturated monomer is compatible with a binder polymer. Examples thereof include esters of alcohols such as t-butyl alcohol and lauryl alcohol with acrylic acid and methacrylic acid, or Maleimide derivatives such as laurylmaleimide, cyclohexylmaleimide and benzylmaleimide, or esters of alcohol and fumaric acid such as dioctyl fumarate, furthermore, hexanediol di (meth) acrylate, nonanediol di (meth) acrylate, trimethylolpropanetri (meta) ) Esters of polyhydric alcohols such as acrylates with acrylic acid and methacrylic acid.

As the photoinitiator, aromatic ketones such as benzophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, α-methylol benzoin methyl ether, α-methoxybenzoin methyl ether, 2,2-diethoxy It is selected from known photopolymerization initiators such as benzoin ethers such as phenylacetophenone and used in combination. The photosensitive resin layer can be prepared by various methods. For example, the raw materials to be blended are dissolved and mixed in an appropriate solvent, for example, a solvent such as chloroform, tetrachloroethylene, methyl ethyl ketone, and toluene, cast into a mold, and the solvent is evaporated to form a plate as it is. Can be. Further, the mixture can be kneaded by a kneader or a roll mill without using a solvent, and can be formed into a plate having a desired thickness by an extruder, an injection molding machine, a press or the like.

As a method of providing the photosensitive resin layer on the sleeve, a method in which a photosensitive resin formed in a sheet shape in advance is wound around the sleeve, or a method in which the photosensitive resin composition is wound around the sleeve while being discharged from an extruder or the like. And a method of coating a sleeve with a solvent solution of a photosensitive resin. When winding the photosensitive resin sheet around the sleeve, make sure that there is no gap between the ends of the photosensitive resin.
It is necessary to cut and use the sheet accurately. After winding the photosensitive resin around the sleeve, a process for eliminating the joint is performed. Generally, a method is employed in which the photosensitive resin is heated to a temperature higher than the softening point to melt and bond the ends of the photosensitive resin to each other. The heating time is usually from 20 minutes to 1 hour, and it is determined based on the temperature and the softening point of the resin that the ends are fused together. In addition, the joint can be eliminated by filling the joint with a solvent solution of the photosensitive resin composition. Then, the surface of the photosensitive resin is polished with a grinder to completely eliminate joints and at the same time improve accuracy.

The infrared-sensitive layer used in the present invention, which provides a non-infrared shielding layer which can be cut off by an infrared laser, is a layer which can be ablated by infrared rays and which is substantially opaque to radiation active in the photosensitive resin. It is.
The infrared-sensitive layer comprises at least one binder polymer, at least one infrared-absorbing substance and, if necessary, a non-infrared shielding substance, and the infrared-absorbing substance may also serve as the non-infrared shielding substance. Examples of the binder polymer for the infrared-sensitive layer used in the present invention include polyamides, polyvinyl alcohols, amphoteric interpolymers, cellulosic polymers, ethylene-vinyl acetate copolymers, and poly (vinyl alcohol) disclosed in JP-A-8-305030. Butyral, annular rubber, etc.
No. 6,875, styrene-butadiene copolymer, styrene-isoprene copolymer and the like. These binder polymers are blended in a ratio of 40 to 90% by weight based on the total weight of the infrared-sensitive layer.

As the infrared absorbing material used in the present invention, a simple substance or a compound having a strong absorption in the range of 750 to 2,000 nm is usually used. Examples of such substances include inorganic pigments such as carbon black, graphite, copper chromite, and chromium oxide, and pigments such as polyphthalocyanine compounds, cyanine pigments, croconium pigments, and metal thiolate pigments. These infrared absorbing substances are added in a range that provides sensitivity that can be cut off by the infrared laser beam used. Generally, 20 parts as an infrared absorbing substance based on the total weight of the infrared sensitive layer.
It is added in the range of ~ 80% by weight.

As the non-infrared shielding material, a material that reflects or absorbs ultraviolet light can be used. For example, ultraviolet absorbers, carbon black, graphite and the like are good examples, and the amount of addition is set so that a desired optical density can be achieved. Generally, it is added so as to have an optical density of 2.0 or more, preferably 3.0 or more. Note that the infrared absorbing substance and the non-infrared shielding substance may be the same. The infrared-sensitive layer is formed by preparing an infrared-sensitive coating liquid in which a binder polymer, an infrared-absorbing substance and, if necessary, a non-infrared shielding substance are evenly dissolved or dispersed in a solvent or water, and then applied. it can.

The infrared-sensitive coating liquid is prepared by adding an appropriate solvent directly to a binder polymer, an infrared-absorbing substance, or a non-infrared-shielding substance, forcing stirring using a stirring blade, dispersing using a ball mill, stirring using ultrasonic waves, or mixing them. Such as combined use of, binder polymer and infrared absorbing material,
The non-infrared shielding material is prepared by a method of pre-kneading using an extruder or a kneader and then dissolving in a solvent. Alternatively, an infrared-sensitive coating liquid can be prepared by forcibly dispersing carbon black in a polymer present in a latex solution in advance.

In order to improve the dispersibility of the infrared absorbing substance and the non-infrared shielding substance in the solution, a dispersion of a high molecular weight nonionic surfactant or a phosphoric acid ester of polyoxyethylene alkyl ether or the like is used in the infrared sensitive coating liquid. Agents can be added. Infrared-sensitive coating liquids include silicones, long-chain alcohols, and aliphatic esters in order to suppress the generation of air bubbles when transferring the infrared-sensitive coating liquid from a container, and to eliminate the generated air bubbles in a short time. And antifoaming agents such as metal soaps. Infrared-sensitive coating solutions include perfluoroalkyl compounds and sulfonate-type anionic surfactants for the purpose of improving the wettability and leveling of the coating solution on the surface of the coating, such as photosensitive resin surfaces and polyester films. Surfactants can be added.

As a method for forming an infrared-sensitive layer on the surface of the photosensitive resin, an infrared-sensitive coating liquid is directly applied to the surface of the photosensitive resin by a ring coater, a spray coater or the like, or a polyester or polypropylene or the like is used. After coating on the film, it is performed by laminating and transferring to the surface of the photosensitive resin, but if the photosensitive resin layer is processed in advance into a sleeve shape, it is applied to the surface of the photosensitive resin layer. The method of direct application is effective. Infrared-sensitive layer thickness is determined in consideration of the sensitivity and non-infrared shielding effect ablation using infrared lasers, usually 0.1 to 20 g / m ^2, preferably in the range of 1 to 5 g / m ² Is set.

An infrared laser having a wavelength of 750 to 2000 nm can be used as an infrared laser used to form a mask by image-wise excising the infrared-sensitive layer on the photosensitive resin. As this type of infrared laser, a semiconductor laser of 750 to 880 nm and a Nd-YAG laser of 1060 nm are generally used. The laser generation unit is controlled by a computer together with the drive system unit. By selectively cutting off the infrared-sensitive layer on the photosensitive resin layer, the digitized image information can be converted into a photosensitive composition for flexographic printing. It is given to the body. After image drawing by the laser is completed, the ultraviolet light source used for photo-curing the photosensitive resin layer of the photosensitive composition for flexographic printing plates includes a high-pressure mercury lamp, an ultraviolet fluorescent lamp, a carbon arc lamp, a xenon lamp, and sunlight. And the like. A desired relief image can be obtained by exposing the image surface with ultraviolet rays.

After the photosensitive resin layer is irradiated with ultraviolet rays to form an image, the photosensitive resin layer is used as a developing solvent used for washing out the non-infrared shielding layer and the unexposed portions of the photosensitive resin layer. Any one having a dissolving property can be used. Examples thereof include heptyl acetate, esters such as 3-methoxybutyl acetate, petroleum fractions, hydrocarbons such as limonene and decalin, and tetrachloroethylene and the like. Chlorine solvents and the like are used. It is also possible to use a mixture of these solvents with alcohols such as propanol, butanol and pentanol. The washing of the non-infrared shielding layer and the unexposed portion is performed by spraying from a nozzle or brushing with a brush. The obtained printing plate is rinse-washed, dried and post-exposed to finish.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on examples and the like.

Embodiment 1 Outer circumference 461.15 mm, length 1250 mm
An adhesive Megam 11658 (trade name, manufactured by Kemetal Co., Ltd.) is applied to the outer surface of the nickel sleeve with a wet coating amount of 12
It was spray-coated uniformly at 0 g / m ² and dried at 60 ° C. for 15 minutes. This was covered with TGI stockings (trade name, manufactured by Anderson and Vlieland) while stretching so that the fibers did not overlap.

AFP / AFP for flexographic printing
HD-11 (trade name, manufactured by Asahi Chemical Industry Co., Ltd., 3.18 m thick)
m, a short side of size 762 mm × 1016 mm) was cut to have a size of 465.15 mm × 1016 mm.
After the film on the opposite side of the sheet with the slip layer was peeled off, the above-mentioned sleeve was wound around the above-mentioned sleeve with the side from which the film had been removed facing down to 465.15 mm in the circumferential direction without loosening. However, the length of the sheet was slightly shorter than the circumference of the sleeve. After the gap was connected by pulling with an adhesive tape, the area from 5 cm at both ends of the photosensitive resin sheet to the outside of the sleeve was covered with the adhesive tape without any gap.

The photosensitive resin sheet and the sleeve are brought into close contact with each other by vacuuming the space between the adhesive tape covering the both ends of the sleeve and the sleeve, and the PET film (cover sheet) on the surface of the photosensitive resin sheet is photosensitive. After cutting along the circumference with a cutter knife just inside the adhesive tape wound around both ends of the resin sheet, the cut inner PET film and the slip layer were peeled off and removed. When the entire sleeve was heated at 130 ° C. for 20 minutes while the space between the adhesive tape and the sleeve at both ends of the photosensitive resin sheet was evacuated, the joint of the photosensitive resin sheet became invisible. The seamless photosensitive resin sleeve obtained in this way is applied to a grinding machine, SA6 / 2U × 2.
By setting the resin to 00 (manufactured by Schleif-Maschinenwerk (Germany)) and polishing the outer periphery of the photosensitive resin to 480 mm, a completely seamless sleeve-shaped photosensitive resin was obtained. In this state, the surface of the photosensitive resin had a cloudy white appearance due to roughness caused by grinding.

As a method of surface-treating the seamless sleeve-shaped photosensitive resin and applying an infrared-sensitive coating solution to the surface, a vertical ring coater (manufactured by Takagi Sculpture Co., Ltd.)
Using soft chloroprene (thickness 1 mm, hardness 45)
Degree) was used as the scavenging rubber. The above-described seamless photosensitive resin sleeve and 3-methoxybutyl acetate are set on a ring coater, and the coater containing the solvent is lowered at a speed of 400 mm / min to uniformly disperse the solvent on the surface of the photosensitive resin. Was applied. When this sleeve was allowed to stand at room temperature for 30 minutes, the surface of the photosensitive resin was removed from the roughness due to grind and became a mirror surface.

60 parts by weight of Tufprene 315 (trade name, manufactured by Asahi Kasei Corporation, styrene-butadiene block copolymer having a styrene content of 22% by weight) and general-purpose color black # 30 (trade name, carbon black having a particle diameter of 30 nm) A mixture prepared by kneading 40 parts by weight of a kneader with a kneader was dissolved and dispersed in 3-methoxybutyl acetate to prepare a uniform liquid having a solid content of 5% by weight. After filtering this through 300 mesh SUS (stainless steel), the filtration accuracy is 1μ.
Was filtered through a cartridge filter SL-010 (trade name, manufactured by Loki Techno Co., Ltd.) to obtain an infrared-sensitive coating liquid.

The surface-treated sleeve-shaped photosensitive resin having undergone the above-mentioned surface treatment and the infrared-sensitive coating liquid are set on a ring coater, and the coater containing the coating liquid is lowered at a speed of 400 mm / min. A sensitive coating solution was applied. By leaving this sleeve at room temperature for 30 minutes, an infrared-sensitive layer having no defects such as pinholes could be formed on the photosensitive resin. When this sleeve was set on an infrared laser setter and an image pattern was drawn, a photomask that faithfully reproduced the image data could be formed.

Next, the entire surface of the sleeve-shaped photosensitive resin was coated with an ultraviolet fluorescent lamp of 12 mW / cm ² at 4000 mJ.
/ Cm ² , and washing off the infrared-sensitive layer with a brush using a mixed solvent of Solvesso 150 (trade name, manufactured by Exxon Chemical Company, aromatic hydrocarbon) / benzyl alcohol = 4: 1 (volume); The unexposed portion of the photosensitive resin layer was washed out and dried at 60 ° C. for 1 hour to obtain a good flexographic printing plate without any seams. When this sleeve-shaped flexographic printing plate was mounted on a flexographic printing machine and printing was performed, a good printed matter with good solidity could be obtained.

[0031]

[Comparative Example 1] An infrared-sensitive coating liquid prepared in the same manner as in Example 1 and a sleeve having the photosensitive resin surface which was processed into a sleeve shape in the same manner as in Example 1 and was still roughened by grinding. The photosensitive resin composition was set on a ring coater, and an infrared-sensitive coating solution was applied in the same manner as in Example 1. When this sleeve was allowed to stand at room temperature for 30 minutes, a pinhole was generated in the infrared sensitivity in a portion where local roughness was severe due to grinding. This sleeve was subjected to drawing of an image pattern with an infrared laser, exposure to light, washing off of the infrared-sensitive layer, and washing and drying of the unexposed portion of the photosensitive resin layer in the same manner as in Example 1. The printing plate has a portion where fine points which should not exist in the non-image portion are formed, and in order to obtain a good printing plate, the portion has to be cut off. When this sleeve-shaped flexographic printing plate was mounted on a flexographic printing machine and printing was performed, only a printed matter having a poor solid printing was obtained.

[0032]

Example 2 Acrylic latex; A65 (trade name,
(Asahi Chemical Industry Co., Ltd., solid content concentration 65%, Tg about 7 ° C) 5.
5 parts by weight, acrylic latex; F2400 (trade name, manufactured by Asahi Kasei Corporation, solid content concentration 47%, Tg about 30)
C) 17.6 parts by weight, a wetting agent; 1.5 parts by weight of Nopco Wet 50 (trade name, manufactured by San Nopco, solid content: about 50%), a surfactant; Surflon S-113 (trade name, manufactured by Seimi Chemical Co., Ltd.) , Solid content 30%) 0.05 parts by weight, defoamer SN Deformer 777 (trade name, manufactured by San Nopco, 98% solids) 0.02 parts by weight, 2- (2-butoxyethoxy) ethanol; 1.0 34.3 parts by weight of Unisperse Black B-PI (trade name, manufactured by Ciba Specialty Chemicals) and 40 parts by weight of water, and an ultrasonic cleaner FC-100Z-IA (Japan) (Hucia Co., Ltd.) for 30 minutes. After filtering this through 300 mesh SUS, filtration accuracy 1μ
Was filtered through a cartridge filter SL-010 (trade name, manufactured by Loki Techno Co., Ltd.) to obtain an infrared-sensitive coating liquid.

A sleeve-shaped photosensitive resin structure processed into a sleeve in the same manner as in Example 1 and subjected to a surface treatment;
The coating liquid of Example 2 was set on a ring coater, and 70
The coating of the infrared-sensitive coating liquid was performed by lowering the coater containing the coating liquid at a speed of mm / min. By leaving this sleeve at room temperature for 30 minutes, an infrared-sensitive layer having no defects such as pinholes could be formed on the photosensitive resin. When this sleeve was set on an infrared laser setter and an image pattern was drawn, a photomask that faithfully reproduced the image data could be formed. Next, the sleeve-shaped photosensitive resin composition was exposed in the same manner as in Example 1, and the infrared-sensitive layer was washed away, and the unexposed portion of the photosensitive resin layer was washed out and dried to obtain a good seamless flexographic printing plate. Could be obtained.

[0034]

[Comparative Example 2] An infrared-sensitive coating liquid prepared in the same manner as in Example 2 and a sleeve having the photosensitive resin surface which was processed into a sleeve shape in the same manner as in Example 1 and was still roughened by grinding. The photosensitive resin composition was set on a ring coater, and an infrared-sensitive coating liquid was applied in the same manner as in Example 2. When this sleeve was allowed to stand at room temperature for 30 minutes, only a faint infrared-sensitive layer could be formed. An image pattern was drawn on this sleeve in the same manner as in Example 1, and then exposed, the infrared-sensitive layer was washed away, and the unexposed portion of the photosensitive resin layer was washed out and dried. , The image was buried, and a good flexographic printing plate could not be obtained.

[0035]

According to the present invention, it is possible to reduce the roughness of the plate surface due to the grind and to improve the solidity at the time of printing, and to improve the coating property of the infrared-sensitive coating liquid on the photosensitive resin. It has become possible to obtain an infrared-sensitive layer free from defects such as blurring and pinholes.

Claims (2)

[Claims] 1. A photosensitive resin layer is laminated on a sleeve, and then subjected to a process for eliminating a seam. The surface of the photosensitive resin is completely polished by grinding to completely eliminate the seam. In a method of forming a mask by laser drawing and further exposing an image through the mask and developing an unexposed portion to obtain a seamless printing plate, dissolving a photosensitive resin between the grinding step and the step of providing an infrared-sensitive layer A process for treating the surface of the photosensitive resin with a solvent having a property, the method comprising the steps of: 2. The seamless treatment according to claim 1, wherein the surface treatment of the photosensitive resin is performed by applying a solvent having the solubility of the photosensitive resin to the surface of the photosensitive resin by a ring coater. A method for manufacturing a photosensitive resin sleeve.