JP2001138650A - Laser abrasion paint for forming plate engraving for forming intaglio or letterpress - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser abrasion paint for forming a plate engraving, by which an intaglio or a letterpress can be obtained through the formation of a film, a laser abrasion and a chromium plating, resulting in making an engineering developing process and an engineering etching process unnecessary. SOLUTION: As for the laser abrasion paint for forming a plate engraving forming the intaglio or the letterpress, zinc dusts, a binder polymer, a photoinitiator and a photopolymerizable or photocross-linkable monomer are dispersed in a solvent under the condition that the zinc dusts include an amount, which is enough for forming an electrical chromium plate holding an electrical conductivity in the coated and dried zinc dust film. In a used printing roll, its chromium plate is removed and the film is removed by being polished with a grinding stone so as to form a film for forming a plate engraving in order to produce a required film thickness, through which no surface of a base material to be processed is exposed when the laser abrasion is executed. Next, by irradiating a corresponding portion with laser beams, the coated portion is abraded and then a chromium plate is formed on the abraded portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a laser used in a plate making method, wherein an intaglio or letterpress can be obtained by forming a film and performing laser ablation and chromium plating, thereby eliminating the need for a developing step and an etching step. Related to ablation material.

[0002]

2. Description of the Related Art A gravure plate making method by a conventional etching method, which is a ballad plating type gravure plate making method, is manufactured by, for example, the following steps 1) to 13). 1) Ballad plating is cut and removed by hand using wrench and pliers. 2) Measure the diameter of three to five points from one end to the other end of the printing roll, and eliminate the roll with low roundness accuracy and the roll with low cylindrical accuracy. 3) After performing the releasable surface treatment, ballad plating is performed so that the film thickness is about 60 to 80 μm. 4) Polish the cylinder to remove the plating surface with a medium finishing whetstone # 800 to # 1200. 5) Polish with # 1500 to # 4000 top finish whetstone to minimize surface roughness. 6) Mirror polishing with buff. 7) Apply a negative transparent photosensitive film. 8) The non-image area is exposed and cured by an argon laser. 9) Remove the unexposed resist by alkali development to form an image area where copper plating is exposed. 10) Etch the exposed copper surface with dilute sulfuric acid to form cells. 11) Strip resist with strong alkaline solution. 12) Plate with chrome. 13) Deburr the chrome plating.

A gravure plate making method using a conventional electronic engraving machine is manufactured by, for example, the following steps 1) to 12). 1) The chromium plating is removed by etching with an aqueous solution of dilute sulfuric acid. 2) Measure the diameter of three to five points from one end to the other end of the printing roll, and eliminate the roll with low roundness accuracy and the roll with low cylindrical accuracy. 3) Perform corrective polishing to achieve precise cylindrical accuracy with a # 350 rough finish whetstone. 4) Using the same coarse finishing whetstone, perform plate drop polishing until the cells with the maximum depth are eliminated. 5) Polish the surface with a coarse finishing whetstone of # 500 and a rough finishing whetstone of # 800 in order to reduce the surface roughness. 6) Nickel plating so that the plating thickness is about 15 μm, and then copper plating so that the plating thickness is about 80 μm to 100 μm. 7) Polish the cylinder with a semi-finishing whetstone # 800 to # 1200 to remove the plating surface. 8) Polish the surface with # 1500 to # 4000 top finish whetstone to minimize surface roughness. 9) Mirror polishing with buff. 10) Form cells with an electronic engraving machine. 11) Chrome plating. 12) Deburr chrome plating.

[0004]

Problems with the conventional gravure plate making method by the etching method are as follows. (1) Removal of copper plating (ballard plating or plate drop polishing) and copper plating for reuse are performed. Was uneconomical. (2) The number of grinding steps was large. (3) The grinding stone could not be satisfactorily polished, and pitch lines were formed. The pitch is defined as a spiral with a high and a low part formed like a screw thread, even though the surface roughness is uniform. This means that the long direction of the stripe appears as the roll surface length direction. (4) Mirror polishing was performed by buffing. (5) Photosensitive film coating-image printing-development-etching steps were performed. However, when the thickness of the photosensitive film was 2 .mu.m and 4 .mu.m, the photosensitive characteristics with respect to laser light differed greatly, leaving development residues or side etch. There was a sensitivity that it occurred greatly. In addition, there are problems with the conventional gravure plate making method using an electronic engraving machine: (1) copper plating for removal (plate drop polishing) and copper plating for re-use were performed, which was uneconomical. (2) The number of grinding steps was large. (3) The grinding stone could not be satisfactorily polished, and pitch lines were formed. (4) Mirror polishing was performed by buffing.

On the other hand, a laser ablation technique has recently attracted attention, and a technique has emerged in which a plate-making roll is black-coated by about 2 to 4 μm, ablated by a yag laser, etched, and then chromium-plated. In this plate making method, a black resin film is formed instead of a process of forming a photosensitive film-forming a latent image by laser exposure-
Ablation process using a yag laser.
Work in a bright room can now be performed, and the developing step can be omitted. In addition, the above-mentioned drawbacks of the conventional plate making method can be avoided. However,
In the plate making method using laser ablation, residues that cause poor etching may remain, and it is necessary to perform plate polishing and then copper plating to perform cylindrical polishing and mirror polishing when recycling.

[0006] The present invention provides a laser ablation material used in a plate making method, in which an intaglio or letterpress can be obtained by forming a film and performing laser ablation and chromium plating, thereby eliminating the need for a development step and an etching step. It is intended to be.

[0007]

According to the first invention of the present application, zinc powder, a binder polymer, a photoinitiator, and a monomer having photopolymerization or photocrosslinkability are dispersed in a solvent, and dipping is performed. The viscosity is adjusted by the coat so that a coat thicker than the depth dimension of the cell or relief can be formed, and the zinc dust contains the necessary amount to make the coat conductive when applied and dried to enable electrochromic plating. It is intended to provide a laser ablation coating material for forming a plate depth for forming an intaglio plate or relief plate.

In the second invention of the present application, carbon black, a binder polymer, a photoinitiator, and a monomer having photopolymerizability or photocrosslinkability are dispersed in a solvent, and a cell or relief of the cell or relief is formed by dipping coating. The viscosity is adjusted so that a film thicker than the depth dimension can be formed, and the amount of carbon black includes the necessary amount that allows the film to retain conductivity and be electrochromic when applied and dried. An object of the present invention is to provide a laser ablation paint for forming a printing plate depth for forming an intaglio or relief printing plate.

The third invention of the present application is directed to a cell or relief in which zinc powder, carbon black, a binder polymer, a photoinitiator, and a photopolymerizable or photocrosslinkable monomer are dispersed in a solvent. The viscosity is adjusted so that a film thicker than the depth dimension of the film can be formed, and the total amount of zinc dust and carbon black is determined by the amount required to make the film conductive and electrochromic plating when applied and dried. It is intended to provide a laser ablation paint for forming a plate depth for forming an intaglio or letterpress, characterized by including the above.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A laser ablation paint for forming an intaglio plate or a relief plate according to the first invention of the present application comprises a solvent, zinc dust, a binder polymer,
A photoinitiator and a monomer having photopolymerizability or photocrosslinking property are dispersed, and zinc powder is used in an amount required to allow the coating to retain conductivity when applied and dried to enable electrochromic plating. It is characterized by including. Specifically, for example, a binder polymer (5%), a photoinitiator (10%), a photopolymerizable or photocrosslinkable monomer (5%), and a zinc powder having a particle size of about 1 to 2 μm are used in a volume ratio. (70-60
%) And carbon black (10 to 20%) are dispersed in a solvent so as to have the same viscosity as paint paint. According to the second invention of the present application, a laser ablation paint for plate depth formation for forming an intaglio or letterpress is a solvent, carbon black, a binder polymer, a photoinitiator, and a photopolymerizable or photocrosslinkable. And the amount of carbon black is characterized in that the amount of carbon black includes the necessary amount that allows the coating to retain conductivity when applied and dried to enable electrochromic plating. . Specifically, for example, as a laser ablation material capable of chromium plating, for example, a binder polymer (5%), a photoinitiator (10%), and a photopolymerizable or photocrosslinkable monomer (5%) ) And the particle size is 1-2μ
This is a viscous liquid in which zinc powder at the m level (80%) is dispersed in a solvent so as to have the same viscosity as paint paint. According to the third invention of the present application, a laser ablation paint for plate depth formation for forming an intaglio or relief printing plate, a solvent, zinc dust, carbon black, a binder polymer, a photoinitiator, a photopolymerizable or A monomer having photocrosslinking property is dispersed, and the total amount of zinc dust and carbon black includes a necessary amount to make the film conductive and electrochromic plating when applied and dried. It is characterized by the following. Specifically, for example, as a laser ablation material capable of chromium plating, for example, a binder polymer (5%), a photoinitiator (10%), and a photopolymerizable or photocrosslinkable monomer (5%) ) And carbon black (80%) are dispersed in a solvent so as to have the same viscosity as paint paint.

Therefore, when the laser ablation paint for forming a plate depth for forming the intaglio or relief plate according to the first, second and third aspects of the present invention is used, the following recycle plate making can be performed. In the case of a disposable plate, the first to third steps are omitted. First step: removal of chrome plating. Second step: Removal of the plate-forming coating by grinding stone grinding / returning to a printing substrate roll which is a plate-making substrate to be used repeatedly. Third step: Diameter measurement and elimination of inaccurate rolls. Fourth step: a wettability surface treatment is performed. Fifth step: A laser ablation film having a thickness of 30 to 50 μm using the laser ablation paint of the present invention.
Coating and curing of the coating by UV irradiation. Sixth step: formation of an intaglio or letterpress by ablation using a high-power laser such as a yag laser. Seventh step: electrochromic plating. Eighth process: Sanding and chrome plating deburring.

The laser ablation paint according to the present invention is designed to prevent the electrochrome plating from backfilling the engraved intaglio or letterpress (for example, 10 to 20 μm).
In order to prevent the surface of the plate-making substrate from being exposed during laser ablation, a plate-forming film is formed to have a thickness much larger than a normal coating film (2 to 4 μm), for example, a thickness of 30 to 50 μm. There is a need. For example, if a thin film of about 10 microns is formed, the bottom of the gravure plate cell becomes the plate-forming substrate surface (copper-plated surface) by laser ablation, and in the shadow portion, the bonding force of the film to the plate-forming substrate surface is reduced. There is a problem that the doctor does not have a sufficient resistance to the ink scraping force of the doctor and that the plating is often applied to the copper plating surface at the bottom of the cell to fill the cell.

In the present invention, a photoinitiator and a monomer are contained as necessary components of the laser ablation paint. It takes about 20 minutes to dry with a coating film of 2 to 4 μm. For a coating film of 30 to 50 μm, it takes about one hour under the same drying conditions. In the present invention, since the photoinitiator and the monomer are contained, the coating film can be cured in an extremely short time by applying light having a wavelength sensitive to the photoinitiator to the coating film after coating. For this reason, the process time can be reduced.

In the present invention, the extremely large amount of zinc dust and / or carbon black is determined as described above.
This is because a coating film having a thickness of about 50 [mu] m is formed and the photo-cured film is provided with sufficient conductivity to enable good electrochromic plating. Dozens of μm film thickness where the surface of the plate making substrate is not exposed when laser ablation is performed, specifically,
The plate-forming coating is preferably formed to have a thickness of 30 to 50 μm. The reason is that, for example, when the film thickness is reduced to 10 μm, the bottom of the cell of the gravure plate becomes the plate forming substrate surface (copper plated surface) when laser ablation is performed, and in the shadow portion, the coating is bonded to the plate forming substrate surface. This is because the force does not have a sufficient resistance to the ink scraping force of the doctor, and there is a problem that the plating is often applied to the copper plating surface at the bottom of the cell to fill the cell. Since the present invention does not perform etching, problems such as poor etching due to development residues do not occur. Rather, in the present invention, it is important that the substrate surface for plate formation is not exposed at the bottom of the cell of the gravure plate when the laser ablation is performed by increasing the film thickness. The binder polymer may be a combustible substance (any one of nitrocellulose, ethylene-vinyl acetate copolymer, unsaturated polyester resin, epoxy resin, allyl resin, polyurethane resin, polyethylene, polypropylene, polystyrene, polyacetal, natural rubber, etc.) Or a plurality of types: 75% by weight, and an oxidizing agent (ammonium nitrate or chloric acid compound:
10% by weight).

Hereinafter, each step will be described in detail. In the first step of removing the chromium plating, the used printing roll is etched with dilute sulfuric acid to remove the chromium plating. Laser ablation material cannot be removed. A chrome plating can be removed by taking a used printing roll from a printing company, chucking and rotating the used printing roll at both ends, and immersing it in dilute sulfuric acid in a tank for several minutes. In addition, it applies to not only the roll plate but also the plan plate.

The step of removing the plate-forming film in the second step is as follows:
The laser ablation material is removed by grinding.
Laser ablation materials cannot be removed with solvents. #
With a PVA grindstone for finishing or precision finishing of 4000 to # 6000, it is enough to polish the laser ablation material and to completely expose the copper plating surface. Polishing of the copper plating surface is suppressed to less than 5 μm. Polishing method is, for example, # 60
The PVA grinding wheel of 00 prevents the extension of the rotation axis of the grinding wheel from intersecting with the rotation axis of the plate-making roll, and the rotation of the grinding wheel when viewing the extension of the rotation axis of the grinding wheel and the rotation axis of the plate-making roll from a plane direction. Since the extension line of the shaft is in a crossed state inclined at an angle smaller than a right angle with respect to the rotation axis of the plate making roll, about half of the chord line parallel to the diameter line which is off the center hole of the end face of the grinding wheel is used for the plate making roll. Make the plate making contact with the bus bar, increase the rotation speed of the plate making roll from the time of precision finishing polishing, press the grindstone against the plate making roll at the polishing pressure at the time of precision finishing polishing, and follow the grinding wheel with the rotation of the plate making roll. It is preferable that the grinding wheel is moved in the direction of the surface length of the plate making roll, or is performed by using a # 4000 PVA grinding wheel so that the extension of the rotation axis of the grinding wheel does not cross the rotation axis of the plate making roll and Whetstone When the extension line of the rotation axis and the rotation axis of the plate-making roll are viewed from the plane, the extension line of the rotation axis of the grinding wheel is perpendicular to the rotation axis of the plate-making roll. It is preferable to perform polishing to reduce the surface roughness, which is performed in a state in which a chord line parallel to the diameter line is brought into contact with the generatrix of the plate-making roll.

In the third step of measuring the roll diameter and eliminating the roll having an inaccurate accuracy, the printing substrate roll is mounted on a roll diameter measuring device, and from one end to the other end of the printing substrate roll, at a constant pitch, for example, 10 mm. For each pitch, the diameter is measured with an accuracy of, for example, 5 μm (not shown). As a result of this measurement, a roll having a low roundness accuracy and a roll having a low cylindrical accuracy are not suitable for recycling and are therefore excluded.

In the step of applying the fourth wettability surface treatment, for example, a 0.15% aqueous solution of a silane coupling agent or a mixed solution of distilled water and a small amount of ammonia is sprayed and dried.

The step of forming a fifth plateable laser ablation film is performed by a dipping method or a scan coating method using a laser-ablationable, conductive, chromium-plateable material using a yag laser or an excimer laser. 30μ by law (Japanese Patent Application No. 1-246049)
It is applied uniformly to a thickness of m to 40 μm and dried.

The sixth step of forming an intaglio or letterpress by laser ablation is to irradiate a portion corresponding to an image portion on a film by using a yag laser or an excimer laser to irradiate the film with a laser ablation. Ration. That is, the laser beam is absorbed by the film, converted into heat, and heated and evaporated instantaneously, thereby forming an intaglio or letterpress. When the undercoating surface of the coating, that is, a conductive surface such as a copper plating surface is exposed, the electrical conductivity between the conductive surface and the laser ablation material is different and plating is not performed well, so that the depth of engraving by laser ablation is performed. Is less than the thickness dimension. If the laser ablation material does not contain zinc dust, a semiconductor laser that emits laser light having a wavelength of about 800 nm can be used.

In the seventh chrome plating step, since the printing surface of the copper-plated plate does not have a printing durability, 5
Chrome plating of ~ 7 μm.

In the eighth step of sanding and chrome plating deburring, the chromium plating causes burrs on the edges of the cells, so that the burrs are removed and the non-image areas are not mirror-finished but are not properly mirrored. This is performed in order to prevent the occurrence of plate fogging as a surface having a self-lubricating property with respect to the doctor blade by forming a sandpaper mark.

[0023]

The laser ablation material of the first invention of the present application has the following effects. (1) When a laser ablation material is applied to the plate forming surface of the plate substrate, for example, 30 μm to 50 μm and dried to dryness, if light of a wavelength that the photoinitiator is sensitive to is irradiated, radicals of the photoinitiator are converted to monomers. As soon as it acts, a curing reaction occurs and the drying time is short. When the laser ablation material is applied by a scan coating method, work in a bright room can be performed only by preventing light having a wavelength sensitive to the photoinitiator from irradiating the periphery including the application head. (2) When a laser ablation material is applied to the plate forming surface of the plate base material and dried, the plate forming film is dried and flashed with a laser beam of a high-power laser such as a yag laser according to the image data and scanned. , Intaglio or letterpress can be formed. The zinc dust constituting the laser ablation material is instantaneously gasified and scattered by the thermal energy of the laser beam. As can be seen from galvanized pipe welding, the zinc dust gas is oxidized and has no particular harm to the human body. Laser ablation work can be performed in a bright room. (3) Laser engraving of the plate by laser ablation so that the thickness of the plate-forming film is reduced by adjusting the intensity of the laser beam and applying it so that the plate-forming film is thick. If the plate is made of copper or other conductive metal, the plate-forming film also contains a large amount of zinc dust. And conductive, hard chrome plating for securing printing durability on the plate surface can be performed satisfactorily. (4) In order to reuse the plate substrate (print roll) after printing, it is sufficient to remove the plate-forming coating with a polishing device.
Thereby, the plate forming surface of the plate substrate (printing roll) is about 5
Since it is polished by about μm, it is sufficient to perform copper plating or the like for restoring the plate-formed surface of the plate substrate (printing roll) at a rate of once in dozens of reuses. (5) Since intaglio or letterpress can be formed by the above steps (1), (2), (3) and (4), the process can be remarkably shortened, and the coating device, laser ablation device, chrome plating device, and plate forming It is sufficient to prepare a polishing apparatus for removing the coating film and regenerating the plate substrate (printing roll), and the plate making factory can be made significantly smaller than in the past. (6) Since the steps of development and etching can be eliminated, dependence on organic chemistry and inorganic chemistry is reduced. In the wet process, only a film is formed by coating, and waste liquid treatment is eliminated.
Since development and etching are eliminated, skill and data management such as the type of water to be used, temperature control and time control are released, and a highly reliable plate making can be established.

The laser ablation material of the second invention has the following effects. Since the laser ablation material of the second invention is configured so that electrochromic plating can be performed by containing a large amount of carbon black in place of the zinc dust of the laser ablation material of the first invention, Effect of invention of laser ablation material
The same effects as (1) to (6) can be obtained. When carbon black is used instead of zinc powder, ablation can be performed with a large and small heat energy capable of absorbing the heat of laser light.

The laser ablation material of the second invention has the following effects. Since the laser ablation material of the third invention is configured so that electrochromic plating can be performed by adding carbon black to the zinc powder of the laser ablation material of the first invention, the laser ablation material of the first invention can be used. Effects equivalent to the effects (1) to (6) of the invention can be obtained. Since carbon black is contained in the zinc powder, the ability to absorb heat of laser light is large and ablation can be performed with small thermal energy.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // G03F 7/00 501 G03F 7/00 501 F Term (Reference) 2H084 AA14 AA36 BB02 BB16 CC01 CC03 2H096 AA02 AA15 BA05 BA20 EA02 GA45 GA46 HA27 JA04 2H114 AA01 AA03 AA24 BA01 DA03 DA04 DA43 DA46 DA50 DA52 DA55 DA56 DA60 DA75 DA79 EA01 EA03 EA08 GA03 GA07 GA29 GA32 4J038 EA011 FA012 HA026 HA066 KA03 KA08 KA20 NA20

Claims (3)

[Claims] 1. A solvent in which zinc dust, a binder polymer, a photoinitiator, and a monomer having photopolymerization or photocrosslinkability are dispersed, and the zinc dust is applied when dried to dryness. A laser ablation paint for forming a plate depth for forming an intaglio or letterpress, characterized in that the coating has a necessary amount to have conductivity so that electrochromic plating can be performed. 2. A solvent in which carbon black, a binder polymer, a photoinitiator, and a monomer having photopolymerization or photocrosslinking properties are dispersed, and the amount of carbon black is applied to dryness. A laser ablation paint for forming a plate depth for forming an intaglio or letterpress, wherein the coating sometimes contains a necessary amount to impart conductivity to the coating and allow electrochrome plating. 3. A solvent in which zinc dust, carbon black, a binder polymer, a photoinitiator, and a photopolymerizable or photocrosslinkable monomer are dispersed, and the total amount of zinc dust and carbon black is Is a laser ablation paint for forming a plate depth for forming an intaglio or letterpress, characterized in that it contains a necessary amount to impart conductivity to the film when applied and dried to form electrochrome plating. .