JP2901225B2 - Screen printing plate manufacturing method - 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 screen printing plate using a liquid photosensitive resin.

[0002]

2. Description of the Related Art It is conventionally known to manufacture a screen printing plate by applying a photosensitive resin solution to a screen to form a screen printing plate material, and exposing and developing the material. At this time, the photosensitive resin solution used is, for example, an aqueous solution in which a dichromate or a diazonium salt is mixed with polyvinyl alcohol, or an aqueous solution in which a dichromate or a diazonium salt is mixed with a polyvinyl alcohol-vinyl acetate copolymer. Is used. As described above, since the photosensitive resin is used in the form of a solution, the photosensitive resin solution is applied to the screen surface, and then dried,
A solvent such as water is volatilized to form a screen printing plate material. However, with such a coating and drying method, it is extremely difficult to increase the thickness of the photosensitive resin layer formed on the screen (for example, to a thickness of about 0.1 mm or more). It has been extremely difficult to produce a thick screen printing plate that sufficiently satisfies the required performance.

[0003] The reason why such a thick film screen printing plate is desired is as follows. That is, a screen printing plate can generally transfer a large amount of printing ink to a printing medium and can perform printing in which an image portion of a printed material is raised. . This is because it is advisable to increase the thickness of the screen printing plate itself, that is, to increase the thickness of the photosensitive resin layer corresponding to the non-image portion, in order to further raise the image portion.

In order to obtain such a thick screen printing plate, it is generally difficult to apply a photosensitive resin solution to the screen. For example, a method of applying the photosensitive resin solution over and over the screen many times is conceivable.However, it is impractical to perform the overcoating many times because the work time is long, and the drying is performed many times. There is also a risk that the photosensitive resin may cause a dark reaction by repeating the above.

[0005] Therefore, it has been attempted to produce a screen printing plate using a liquid photosensitive resin without using a photosensitive resin solution. The liquid photosensitive resin changes from a liquid state to a solid state by irradiation with actinic rays, and is a solventless photosensitive resin. Therefore, there is no need to dry it as in the conventional photosensitive resin solution,
There is little danger that the photosensitive resin will cause a dark reaction.

[0006] However, when this liquid photosensitive resin is applied to the screen surface, the photosensitive resin sometimes passes through the mesh of the screen and flows around the squeegee side. If the photosensitive resin adheres to the squeegee side of the screen, there is a disadvantage that image formation varies during printing. Therefore, in the screen printing plate, the screen must occupy a fixed position near one surface of the photosensitive resin layer.

When a liquid photosensitive resin is used,
In order to avoid the above-mentioned drawbacks, it has been proposed that a screen is preliminarily filled with a photosensitive resin solution (to close the mesh), and then a liquid photosensitive resin is applied to obtain a thick screen printing plate. (JP-A-55-26503,
JP-A-53-91804). With such a method, it is possible to sufficiently prevent the liquid photosensitive resin from going around the squeegee side of the screen. However,
The application of the photosensitive resin solution and the application of the liquid photosensitive resin must be used in combination, which sometimes complicates the operation. Further, when the affinity of both photosensitive resins is poor, the adhesion between the photosensitive resins is poor, and there is a possibility that an image may fall off.

[0008]

Accordingly, the present invention utilizes the fact that, when a liquid photosensitive resin is in contact with oxygen, it is difficult to cure even when exposed to actinic light and is exposed to light. By adopting a completely different method, without using a photosensitive resin solution, using only a liquid photosensitive resin, a thick screen printing plate with no photosensitive resin attached to the squeegee side of the screen, That is, an object of the present invention is to provide a method for obtaining a thick screen printing plate in which the screen occupies a certain position near one surface of the photosensitive resin layer.

[0009]

That is, according to the present invention, after a film for image formation is placed on a transparent plate, a liquid photosensitive resin is applied to the film for image formation to a predetermined thickness, and the liquid By irradiating the top surface of the photosensitive resin with the atmosphere and irradiating active light from below the transparent plate to the top surface of the liquid photosensitive resin, the top surface of the liquid photosensitive resin that is in contact with the atmosphere After curing the exposed portion, which is the remaining portion of the liquid photosensitive resin, without curing only the liquid photosensitive resin, a screen (solid photosensitive resin agent is applied on the upper surface of the liquid photosensitive resin).
Excluding those that are ) Is placed and embedded, and then an oxygen-impermeable film is adhered to and laminated on the upper surface of the liquid photosensitive resin in which the screen is embedded, and then actinic light is applied from below the transparent plate to the upper surface of the liquid photosensitive resin . It was irradiated to, to cure the top surface of the liquid photosensitive resin, a process for producing a screen printing plate, characterized by subsequently removing the unexposed portions of the liquid photosensitive resin.

First, in the present invention, a transparent plate is prepared. Since the transparent plate transmits the active light beam at the time of exposure, any transparent plate can be used as long as it is transparent enough to transmit the active light beam. For example, a glass plate or a transparent synthetic resin plate is used. Then, for example, a positive film is placed on the transparent plate. In the positive film, the image area is opaque to actinic rays and the non-image area is opaque to actinic rays. Therefore, when the liquid photosensitive resin used in the present invention is exposed using a positive film, the liquid photosensitive resin corresponding to the non-image area is cured, and the liquid photosensitive resin corresponding to the image area is cured. The reactive resin does not cure.

Next, a liquid photosensitive resin is applied to a predetermined thickness on the positive film. This coating is performed by using a bucket type coater, knife coater, roller coater or the like. The coating thickness of the liquid photosensitive resin is arbitrary, but generally, when a thick screen printing plate is desired, the coating thickness is preferably about 0.1 to 3 mm. The liquid photosensitive resin may be directly applied on the image forming film, or may be applied on the synthetic resin film after laminating a synthetic resin film (cover film) on the image forming film. You may.

The liquid photosensitive resin used in the present invention is a solventless photosensitive resin that changes from a liquid state to a solid state by irradiation with actinic rays, and is mainly used in producing relief printing plates. Is what it is. Examples of the liquid photosensitive resin include an unsaturated polyester resin having a photosensitizer and a heat stabilizer added thereto, or an unsaturated resin having an unsaturated group introduced into a prepolymer such as acryl, urethane, epoxy, or polyester. To which a photosensitizer or a heat stabilizer is added. As specific examples of the liquid photosensitive resin, APR (manufactured by Asahi Kasei Kogyo Co., Ltd.), Tevista (manufactured by Teijin Limited), or the like can be used.

When the liquid photosensitive resin is applied in this manner, the upper surface of the liquid photosensitive resin is in contact with the atmosphere. On the other hand, the lower surface of the liquid photosensitive resin is in contact with the image forming film or the cover film and is not in contact with the atmosphere. Of course, an intermediate portion from the lower surface to the upper surface of the liquid photosensitive resin is not in contact with the atmosphere. The liquid photosensitive resin in this state is exposed to actinic rays through a positive film, for example, to be exposed. Then, in the non-image portion of the positive film, the actinic ray is transmitted well, and the liquid photosensitive resin at the exposed portion is cured. On the other hand, in the image area of the positive film, the actinic rays are blocked, and the liquid photosensitive resin in the unexposed area is not cured. Here, a characteristic feature of the present invention is that the upper surface of the liquid photosensitive resin which is in contact with the atmosphere does not cure even when exposed to actinic rays and exposed. This is a characteristic of the liquid photosensitive resin, and when exposed to oxygen, it does not cure even when exposed. Therefore, the liquid photosensitive resin is hardly cured on the upper surface which is in contact with the atmosphere regardless of the exposed portion and the unexposed portion.
In the present invention, “not cured” does not mean that the composition is not cured at all, but means that the composition is not physically cured and still maintains liquid fluidity. In addition, the meaning of being cured means that it is substantially cured and does not maintain a liquid state.

In the present invention, a screen is placed on the upper surface of the uncured liquid photosensitive resin. Then, this screen is embedded in the upper surface of the uncured liquid photosensitive resin. Since the thickness of this uncured top surface is about the same as the thickness of the screen,
Although the screen is not completely embedded in the liquid photosensitive resin, a fixed portion of the thickness of the screen is embedded. That is, a part of the screen is slightly exposed, and most of the screen is embedded in the liquid photosensitive resin. Also, the reason that the screen is not embedded in the liquid photosensitive resin any more is that the portion located below the upper surface of the liquid photosensitive resin is hardened, so that the screen is supported by this hardened portion. . Here, as the screen to be used, any screen that is conventionally used for screen printing is used. For example, a knitted fabric woven or woven with a silk thread, a nylon thread, a polyester thread, a steel filament, or the like is suitable. Further, it is preferable to employ a mesh having a size of about 4 to 300 mesh.

Next, an oxygen impermeable film is laminated on the surface where the screen is embedded. At this time, the oxygen impermeable film is laminated in close contact with the upper surface of the liquid photosensitive resin. Here, the meaning of the close contact means that substantially no air is present between the oxygen impermeable film and the surface of the liquid photosensitive resin. That is, this is for preventing the liquid photosensitive resin from coming into contact with oxygen so as to be cured well when exposed. As the oxygen impermeable membrane, a synthetic resin film generally used for food packaging or the like can be used, and in addition, a metal foil or the like can be used. In short, any oxygen-impermeable membrane can be used as long as it does not substantially transmit oxygen. In the present invention, the reason for using the oxygen impermeable film is to prevent oxygen from contacting the upper surface of the liquid photosensitive resin and to prevent the liquid photosensitive resin from being cured by the influence of oxygen when exposed. It is. Note that, here, the explanation has been made mainly on stacking the oxygen impermeable film after the screen is embedded in the liquid photosensitive resin surface, but the screen and the oxygen impermeable film are stacked in advance, and the laminate is formed. May be simultaneously brought into contact with the surface of the liquid photosensitive resin, and the screen may be embedded in the surface of the liquid photosensitive resin, and the oxygen impermeable film may be laminated in close contact with the upper surface of the liquid photosensitive resin.

As described above, after the oxygen-impermeable film is laminated on the upper surface of the liquid photosensitive resin in close contact with the liquid photosensitive resin, an actinic ray is directed from the lamp provided below the transparent plate toward the liquid photosensitive resin. Irradiate and expose again. Then, for example, in the non-image portion of the positive film, the actinic ray is transmitted well to the upper surface of the liquid photosensitive resin, and the upper surface of the exposed portion of the liquid photosensitive resin is cured. On the other hand, in the image area of the positive film, the actinic rays are blocked, and the upper surface of the liquid photosensitive resin that is not exposed is not cured. After generating an exposed portion (cured portion) and an unexposed portion (uncured portion) at all portions of the liquid photosensitive resin,
If development is carried out with an aqueous solvent or an organic solvent, the unexposed portions that have not been cured are removed. As described above, the screen printing plate is manufactured.

[0017]

The method for producing a screen printing plate according to the present invention will be described below with reference to the drawings. First, as shown in FIG. 1, a transparent plate 1 is prepared, and an image forming film 2 is placed on the transparent plate 1 (see FIG. 1). Next, a pair of thickness adjusting pieces 3 are provided at predetermined intervals. Next, the liquid photosensitive resin 4 is applied on the image forming film 2. In general, the thickness of the liquid photosensitive resin 4 is slightly higher than the height of the thickness adjusting piece 3 provided in advance. Then, in this state, the liquid photosensitive resin 4 is exposed to active light emitted from a lamp 8 located below the transparent plate 1 (see FIG. 3). As described above, the exposed portion of the remaining portion of the liquid photosensitive resin 4 is cured without curing the upper surface (the surface in contact with the atmosphere) of the liquid photosensitive resin 4. Then, the screen 5 is placed on the upper surface of the liquid photosensitive resin 4 (see FIG. 4). Subsequently, both ends of the screen 5 are pressed down to be buried in the upper surface of the liquid photosensitive resin 4 (see FIG. 5). When the screen 5 can be embedded on the upper surface of the liquid photosensitive resin 4 by its own weight, it is not necessary to press both ends of the screen 5 downward. Then, an oxygen impermeable film 6 is laminated on the upper surface of the liquid photosensitive resin 4 in close contact (see FIG. 7).

After the screen 5 is placed on the liquid photosensitive resin 4, an oxygen-impermeable film 6 is laminated on one end of the screen 5, and the other end of the screen 5 is slightly pressed by a roller 7. Move toward. At this time, the oxygen-impermeable film 6 is entirely laminated while being fed out (see FIG. 6). According to such a method, the screen 5 is buried on the upper surface of the liquid photosensitive resin 4 and the oxygen impermeable film 6 is brought into close contact with the upper surface of the liquid photosensitive resin 4 by a slight pressure by the roller 7. They are stacked (see FIG. 7). Then, after obtaining the laminate as shown in FIG.
Actinic light emitted from a lamp 8 located below
The liquid photosensitive resin 4 is exposed to light (see FIG. 8). By the above method, a screen printing plate is obtained. As is apparent from the above description, the method for producing a screen printing plate according to the present invention is such that the image forming film first contacts the liquid photosensitive resin, and then the screen is attached to the liquid photosensitive resin. It is. That is, as in the conventional method of manufacturing a screen printing plate, the method of attaching the liquid photosensitive resin to the screen and then contacting the image forming film with the liquid photosensitive resin is a completely opposite method. In this respect, the method according to the present invention is distinguishable from the conventional method.

[0020]

EXAMPLE First, a glass plate having a thickness of 10 mm was prepared. On top of this, a positive film (flower pattern) was placed. At the same time, a thickness adjusting piece having a height of 0.5 mm was placed near both ends of the positive film. Thereafter, a liquid photosensitive resin (APR, manufactured by Asahi Kasei Corporation) was applied on the positive film using a knife coater. The liquid photosensitive resin was made slightly higher than the height of the thickness adjusting piece. Thereafter, the liquid photosensitive resin was irradiated with actinic rays from a high-pressure mercury lamp (2 kilowatts) located 50 cm below the glass plate for 1 minute to expose. As a result, the upper surface of the liquid photosensitive resin was not cured even at the exposed portion, and remained liquid. Next, a polyester screen having a mesh size of 100 mesh was placed on the upper surface of the liquid photosensitive resin. Then, a roller around which a 0.1 mm thick polyester film (oxygen impermeable membrane) is wound is lightly contacted with the upper surface of the thickness adjusting piece, and then the roller is moved from one end of the screen to the other end. While moving, the polyester film was unwound, and the polyester film was closely adhered to the upper surface of the liquid photosensitive resin and laminated.
At this time, the polyester screen was buried in the liquid photosensitive resin by slightly pressing the roller.

After the laminate is obtained as described above, an actinic ray is directed from the high-pressure mercury lamp (2 kW) located 50 cm below the glass plate toward the liquid photosensitive resin.
Exposure for 5 minutes. Thereafter, the polyester screen and the exposed liquid photosensitive resin were taken out, developed with an aqueous developer, and then washed with water and dried to obtain a screen printing plate. This screen printing plate had a thickness of about 0.5 mm. When printing was performed using the screen printing plate, a relief-like printed matter in which an image was greatly raised was obtained.

[0022]

According to the method of the present invention, after a liquid photosensitive resin is applied on an image forming film placed on a transparent plate, an actinic ray is irradiated from below the transparent plate to the exposed portion. The corresponding liquid photosensitive resin is cured. However, the upper surface of the liquid photosensitive resin in contact with the atmosphere (oxygen) is not substantially cured even when exposed. This is a characteristic of the liquid photosensitive resin, and does not sufficiently cure even when exposed to light in the presence of oxygen. Then, when the screen is placed on the upper surface of the uncured liquid photosensitive resin, the screen is embedded in the upper surface. The reason why the screen is not deeply embedded in the liquid photosensitive resin is that the screen is already hardened except for the upper surface of the liquid photosensitive resin, and is not embedded in a portion where the screen is hardened. And, after burying the screen, so that oxygen does not contact the upper surface of the liquid photosensitive resin,
The oxygen impermeable film is tightly laminated on the upper surface of the liquid photosensitive resin. Then, actinic light is again irradiated from under the transparent plate to cure the liquid photosensitive resin corresponding to the exposed portion. At this time, since the oxygen-impermeable film is tightly laminated on the upper surface of the liquid photosensitive resin, the liquid photosensitive resin is cured also on this upper surface.

[0023]

According to the present invention, when the development is carried out after the exposure, the unexposed portions in the liquid photosensitive resin are removed and the exposed portions remain, and a screen printing plate is obtained. The screen printing plate thus obtained has a photosensitive resin layer provided accurately on one side of the screen. This is because the screen is accurately embedded at the position of the upper surface of the liquid photosensitive resin before the final exposure.
Therefore, if the method according to the present invention is employed, the photosensitive resin can be prevented from adhering to the squeegee side of the screen, and the obtained screen printing plate can be easily positioned. By using this, there is an effect that it is possible to perform beautiful printing satisfying the performance required in the market (for example, formation of a thick image).

Further, according to the method of the present invention, it is not necessary to perform clogging of the screen by means such as application of a photosensitive resin solution or the like. You can get a printing plate. Therefore, there is an effect that the production work of the screen printing plate can be prevented from being complicated. Also, since only liquid photosensitive resin is used and other photosensitive resin solution is not used, the strength of the non-image area (cured photosensitive resin) of the screen printing plate is high, This also has the effect of preventing the non-image part from falling off.

[Brief description of the drawings]

FIG. 1 is a side view showing a first step of a method for manufacturing a screen printing plate according to an example of the present invention.

FIG. 2 is a side view showing a second step of the method for manufacturing a screen printing plate according to an example of the present invention.

FIG. 3 is a side view showing a third step of the method for manufacturing a screen printing plate according to an example of the present invention.

FIG. 4 is a side view showing a fourth step of the method for manufacturing a screen printing plate according to an example of the present invention.

FIG. 5 is a side view showing a fifth step of the method for manufacturing a screen printing plate according to an example of the present invention.

FIG. 6 is a side view showing a fifth and sixth step of the method for manufacturing a screen printing plate according to another example of the present invention.

FIG. 7 is a side view showing a sixth step of the method for manufacturing a screen printing plate according to an example of the present invention.

FIG. 8 is a side view showing a seventh step of the method for manufacturing a screen printing plate according to an example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent plate 2 Image forming film 4 Liquid photosensitive resin 5 Screen 6 Oxygen impermeable film 8 Lamp

Claims (2)

(57) [Claims] After placing an image forming film on a transparent plate, a liquid photosensitive resin is applied to the image forming film to a predetermined thickness, and the upper surface of the liquid photosensitive resin is brought into contact with the atmosphere. In this state, by irradiating actinic rays to the upper surface of the liquid photosensitive resin from under the transparent plate, the liquid photosensitive resin is cured without curing only the upper surface of the liquid photosensitive resin in contact with the atmosphere. After the exposed portion, which is the remaining portion of the photosensitive resin, is cured, a screen (solid
Excluding those coated with a photosensitive resin agent. ) Is placed and embedded, and then an oxygen-impermeable film is adhered and laminated on the upper surface of the liquid photosensitive resin in which the screen is embedded, and then actinic rays are applied from below the transparent plate to the upper surface of the liquid photosensitive resin .
A method for producing a screen printing plate, comprising: irradiating a surface of a liquid photosensitive resin, irradiating the surface of the liquid photosensitive resin, and removing an unexposed portion of the liquid photosensitive resin. 2. The burying of the screen and the lamination of the oxygen impermeable film on the upper surface of the liquid photosensitive resin are performed simultaneously.
A method for producing the screen printing plate described in the above.