JP3127967B2 - Manufacturing method of printing plate - Google Patents

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 printing plate having a photosensitive resin layer, and more particularly, to a method for concentrating a solution of a photosensitive resin composition in water and / or an organic solvent. The present invention relates to a method for manufacturing a printing plate material.

[0002]

2. Description of the Related Art Conventionally, photosensitive resin compositions containing a rubber component have been used as flexographic printing plates, and flexographic printing plates are particularly flexible and easily deformable such as cardboard and films. It is necessary that the plate material has an appropriate elastic surface to be used when printing on a printing plate. For example, a photosensitive resin composition containing a water-developable rubber component is, for example, a composition based on a hydrophobic polymer and a hydrophilic polymer having a Tg of 5 ° C. or lower, as described in JP-A-1-219735. can get.

In order to make a printing plate material using the above composition,
After adjusting the composition with water and / or an organic solvent, the solvent is evaporated, and the remaining solvent is concentrated to about 1% by weight or less, then discharged, laminated on a support, and laminated into a sheet having a uniform thickness. It is necessary to mold it. As a conventional technique, as a method of concentrating a composition containing water or an organic solvent, in a batch system, a stirring layer, a kneader, etc., in a continuous system, a thin film evaporator, heating by a vent-type extruder, etc. There is a method of concentrating, especially in the case of a resin composition having insufficient heat stability, a continuous method is preferable.
As described in Japanese Patent Publication No. 0-63333, a twin-screw extruder is particularly preferable as a model in which concentration is performed by a vented extruder, because a twin-screw extruder has a large concentration ability and does not have a vent up of the resin composition. It has been.

[0004]

However, when concentration is performed in one step using a twin-screw extruder, heat generation at the screw tip is severe due to high shearing property, and resin deterioration is apt to occur.
In particular, in the case of a photosensitive resin composition containing a rubber component used for a flexographic printing plate material, the remaining solvent must be reduced to about 1% by weight or less. Therefore, it is necessary to perform high-concentration concentration so that the resin content is 99% by weight or more, and its viscosity becomes tens of thousands poise or more.

[0005] As a method of preventing resin deterioration, there is a method in which a screw shaft is hollow and cooling water is passed through or a twin-screw extruder body is cooled as a jacket. As a result of non-uniform flow due to the occurrence of the temperature distribution, undesirable phenomena such as dead of the flow occur. Therefore, a method of reducing the amount of heat generated, rather than a method of removing the amount of heat, is preferable, and a method of reducing the number of rotations of the screw and preventing the heat is usually employed. However, in the conventional technology, the surface renewal required for uniformly concentrating a composition containing water and / or an organic solvent is insufficient by lowering the number of revolutions, and the concentration becomes nonuniform or the capability is significantly reduced. However, the quality was unstable and the productivity was limited.

[0006]

Means for Solving the Problems The inventors of the present invention have intensively studied for the purpose of improving the above-mentioned problems of the prior art, and have finally completed the present invention. That is, the present invention relates to a method for preparing a photosensitive resin composition containing a rubber component by using water and / or
Alternatively, in a method of producing a printing plate material from an organic solvent solution, the concentration step and the extrusion step are sequentially performed using at least two twin-screw extruders, and water is added to the first twin-screw extruder.
And / or an organic solvent having a resin component content of 85 to 95% by weight.
And concentrated by the second and subsequent twin screw extruders.
It is a method for producing a printing plate material, comprising concentrating to a concentration of at least% by weight .

In the method of the present invention, by using at least two twin-screw extruders, in particular, a vent-type twin-screw extruder, first, a sharp increase in the viscosity of the photosensitive resin composition occurs in the first-stage concentrator. Concentrate to the extent that does not occur. As a result, there is no increase in viscosity as compared with the case of performing high-concentration concentration in a single step, so that the number of revolutions required for uniform concentration can be increased, and further increasing the number of revolutions improves the surface renewal by the screw. The efficiency of concentration is increased, and the productivity is improved. Concentration that does not cause a sharp increase in viscosity is preferably performed when the photosensitive resin composition is 85 to 95% by weight.
It is. If the concentration is less than 85% by weight, the load of concentration in the second and subsequent stages increases, and the same result as in the case of performing high concentration concentration in one stage is not preferable. On the other hand, when the concentration is 95% by weight or more, the viscosity rises sharply, heat generation is remarkable, and resin deterioration occurs, which is not preferable. The resin temperature at which the resin is degraded due to heat generation varies depending on the magnitude of the shearing force by the screw and the residence time.
The temperature is 0 to 100 ° C. or higher, and the resin temperature is preferably 90 ° C. or lower to prevent resin deterioration. Next, the remaining solvent is evaporated and discharged by the second and subsequent vented twin-screw extruders. The second and subsequent vented twin-screw extruders have less residual solvent and require less surface renewal than the first, so that the number of rotations for preventing heat generation can be easily obtained.

The present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic view showing an example of an apparatus used in the method for producing a printing plate material of the present invention. The apparatus shown in FIG. 1 mixes a photosensitive resin composition containing a rubber component with water and / or an organic solvent and adjusts it. A mixing tank 1, a pump 2 for transferring a fixed amount from the mixing tank 1, water and / or an organic solvent Vent-type twin-screw extruder 3 which evaporates the resin component to 85 to 95% by weight, and similarly vent-type twin-screw extruder which concentrates and discharges the resin component to 99% or more Machine 4,
A pump 5 for quantitatively discharging the high-viscosity material, a die 6 for molding the high-viscosity material into a sheet, a support 7 of the photosensitive resin composition such as a metal or a film, and a cover film 8,
Laminating machine 9 for laminating and molding, take-up conveyor 1 for taking over laminated printing plate material
0. Here, it is effective to heat the mixing tank 1 in order to make the mixing and adjustment of the composition uniform in a short time, and the mixing tank 1 is usually passed through the mixing tank 1 having a heated heat medium as a jacket. Can be heated. As the fixed amount transfer pump 2, a screw or a gear pump can be used. The second vented twin-screw extruder 3 has a large amount of water and / or
Alternatively, to evaporate the organic solvent, it is effective to discharge the vapor from the vent port by the vacuum pump 11.
Further, by providing the vent port a at the rear of the supply port, the effect is remarkably increased. The shape of the screw used in the first vented twin-screw extruder 3 is not particularly limited, but a shape excellent in surface renewal is preferable in order to promote evaporation of water and / or an organic solvent. There is a deep groove flight type and a screw with a kneading desk with a kneading effect appropriately arranged. The second vent-type twin-screw extruder 4 can have the same structure as the first vent-type twin-screw extruder 3, but the screw has a low rotation and a high discharge type to prevent heat generation. It is effective for A screw, a gear pump, or the like can be used as the pump 5 for quantitatively discharging the high-viscosity material.

[0009]

The manufacturing method according to the present invention having the above-mentioned structure is characterized in that as a means for removing water and / or an organic solvent from a photosensitive resin composition containing a rubber component, it has a function of concentrating and a method of removing a high-viscosity substance. By providing the extruding function in at least two stages, heat generation due to screw rotation is prevented, and a printing plate material of stable quality is expected to be obtained.

[0010]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. Example 1 A solution prepared by dissolving 21.8 parts of hexamethylene diisocyanate, 15.4 parts of dimethylolpropionic acid, 7.6 parts of polytetramethylene glycol, and 1 part of di-n-butyltin dilaurate in 300 parts of tetrahydrolaran was stirred. Place the tank in the tank equipped with
The reaction was heated to 5 ° C. and continued for 3 hours. In a separate container, acrylonitrile-butadiene oligomer 5 containing a terminal amino group
A solution prepared by dissolving 5.3 parts in 100 parts of methyl ethyl ketone was added to the above tank while stirring at room temperature. The obtained polymer solution was dried under reduced pressure to remove tetrahydrofuran and methyl ethyl ketone to obtain a polymer having an average molecular weight of 21.000. Next, the polymer 100
A solution of 4.8 parts of lithium hydroxide in 100 parts of methyl alcohol was added to a solution of 100 parts of methyl ethyl ketone while stirring at room temperature, and further stirred for 30 minutes to obtain a hydrophilic polymer. . Next, 5 parts of the above hydrophilic polymer, 20 parts of chlorinated polyethylene as a hydrophobic polymer, 5 parts of styrene butadiene rubber, 14 parts of butadiene oligoacrylate 0.5 part of benzyldimethyl ketal, 0.2 part of hydroquinone monomethyl ether 0.2 part
5 parts, water, 55 parts of a mixed solvent of methyl ethyl ketone and tetrahydrofuran were mixed to obtain a photosensitive resin composition solution.

Next, using the apparatus shown in FIG. 1, the composition solution was transferred to the first twin-screw extruder by a gear pump, and the screw was rotated 100 times per minute at a vacuum of 20 Torr from the vent. The solvent was evaporated and concentrated so that the concentration of the photosensitive resin composition became 90% by weight. At this time, the temperature of the resin composition was 85 ° C. Next, it is transferred to the second twin screw extruder, where the screw rotation speed is 30 rotations per minute, and the degree of vacuum is 10T.
At orr, the photosensitive resin composition was concentrated so as to have a concentration of 99.5% by weight. When the temperature of the resin composition at the outlet of the second twin screw extruder was measured, it was 90 ° C.
Next, the mixture was discharged from a die by a gear pump and laminated with a pair of metal rolls heated to 100 ° C. using a polyester film support and a polyester film cover film to obtain a printing plate material having a thickness of 3 mm. Next, the polyester film of the uppermost layer of the obtained printing plate material was peeled off, and a negative film having an image was adhered to the photosensitive resin layer, and exposed to light with a mercury lamp at an illuminance of 25 W / m ² for 5 minutes. After removing the negative film, a brushing phenomenon was performed with neutral water containing 2% by weight of sodium alkylnaphthalenesulfonate at 40 ° C. for 15 minutes. As a result, a clear image pattern having a relief depth of 1.2 mm was obtained.

Comparative Example 1 The photosensitive resin composition solution prepared in the same manner as in Example 1 was rotated by a single pump using a gear pump at a screw speed of 100 revolutions per minute at a vacuum of 20 Torr from the vent. The solvent was evaporated and the photosensitive resin composition was concentrated in one step so that the concentration became 99.5% by weight. At this time, the temperature of the resin composition was 110 ° C. Next, the film was discharged from a die by a gear pump, and laminated with a pair of metal rolls heated to 100 ° C. using a polyester film support and a polyester film cover film to obtain a printing plate material having a thickness of 3 mm. The resulting printing plate material was developed with a brush under the same conditions as in Example 1. As a result, the relief film had a depth of about 0.5 mm, and a negative film image could not be reproduced.

[0013]

By adopting the method of the present invention having the above-described structure, heat generation due to screw rotation is prevented, and a printing plate having a stable quality can be obtained, which contributes to the industry. is there.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of the method of the present invention.

[Explanation of symbols]

 1: Mixing tank 2: Pump 3: First-stage vented twin-screw extruder 4: Second-stage vented twin-screw extruder 5: Pump 6: Die 7: Support body 8: Cover film 9: Laminating machine 10: Pickup conveyor 11: vacuum pump

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G03F 7/00 G03F 7/16 B29C 47/00

Claims (1)

(57) [Claims] 1. A method for producing a printing plate material from a solution of a photosensitive resin composition containing a rubber component in water and / or an organic solvent, wherein a concentration step and an extrusion step are sequentially performed by at least two twin screw extruders. Using the first twin-screw extruder.
Water and / or organic solvent with a resin component of 85 to 95
% Until it reaches a volume% and the second and subsequent twin screw extruders
A method for producing a printing plate material, comprising concentrating to 99% by weight or more .