JPH0147772B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photosensitive resin laminate for making solid relief molds (hereinafter referred to as a resin master plate) with improved plate-making properties. Normally, resin master plates have damage to the surface of the photosensitive resin layer (hereinafter referred to as photosensitive layer) (for example, scratches caused by physical impact), dust, etc.
A film or sheet (usually referred to as a cover film) is tightly coated to prevent the adhesion of dust, dirt, adsorption of oblique air, etc., and to protect the surface of the photosensitive layer. In the case of plate making of a resin master plate, the cover film is peeled off, a negative film is completely adhered to the surface of the photosensitive layer, and the photosensitive resin in the exposed area is cured and insolubilized by exposure baking with actinic rays. A relief mold is obtained by peeling off the negative film and dissolving and removing the photosensitive resin in the unexposed areas (hereinafter referred to as development). However, since the surface of the photosensitive layer is usually somewhat sticky, when the negative film is brought into close contact with the film, air is not partially removed and remains at the interface. Blur tends to occur. As a countermeasure for this, (1) a method using a negative film with a matted emulsion surface, (2) a method of applying fine powder to the surface of the photosensitive layer, and (3) a method of making the surface microporous using an appropriate method as a cover film. By using a method of making the surface microporous by transferring the microporous film onto the surface of the photosensitive layer, a certain degree of air circulation is enabled between the photosensitive layer and the negative film. (4) Layer negative film on the photosensitive layer and apply continuous linear pressure from one end to the other using a roll or the like. , a method of bringing the photosensitive layer and a negative film into close contact under pressure (Japanese Patent Publication No. 48-29727) has been devised, but the matte negative film described in (1) above is usually more expensive than lithographic film. In addition, application of the fine powder in (2) tends to cause uneven coating due to the adhesiveness of the surface of the photosensitive layer, and if the amount of fine powder attached is too large, it will block the transmission of actinic rays, resulting in damage to the photosensitive layer. It has drawbacks such as poor curing. In addition, method (3) is not necessarily effective when the surface of the photosensitive layer is highly adhesive or when the area of the laminate is large, and there are also problems such as making the cover film microporous expensive. be. In addition, method (4) requires a negative laminator, and also has drawbacks such as difficulty in peeling off the negative film after exposure if the surface of the photosensitive layer is highly adhesive.
Each has its own drawbacks, and no fully satisfactory method has yet been found. As a result of intensive research in order to improve this drawback, the present inventors have found that by interposing a non-adhesive anti-adhesive layer between the adhesive photosensitive layer and the cover film, the negative film and the photosensitive layer can be separated. uniform adhesion becomes easier, and plate-making properties are greatly improved.
Furthermore, when a substance with high oxygen barrier properties is used as the anti-adhesion layer, the degree of decrease in sensitivity over time is reduced, and stable plate-making performance can be maintained;
Furthermore, by using a cover film whose surface in contact with the anti-adhesive layer has improved surface tension through corona discharge treatment, the peel strength between the cover film and the anti-adhesive layer is improved, making it easier to cut the resin base plate. The present inventors have discovered that it is possible to prevent peeling at the interface between the cover film and the anti-adhesive layer, and have completed the present invention. That is, the present invention provides a photosensitive resin laminate for making a solid relief mold, which is composed of (1) a cover film, (2) a photosensitive layer, and (3) a support, at least from the upper layer. processed,
Between the (1) cover film and (2) photosensitive layer, there is a layer that is soluble in the developer of the photosensitive layer and has a peel strength with the photosensitive layer that is at least as strong as the peel strength with the cover film.
This is a photosensitive resin laminate for making solid relief molds, characterized by interposing an anti-adhesive layer having a peel strength of 50 g/cm or more and a peel strength of 30 g/cm or more with respect to a cover film. In the present invention, the anti-adhesive layer is interposed between the cover film and the surface of the photosensitive layer,
When cutting the resin base plate, it is necessary that both interfaces do not peel off, and when peeling off the cover film during plate making, it is necessary to peel off with good reproducibility at the interface between the cover film and the anti-adhesive layer. It must not peel off at the interface with the photosensitive layer surface. To this end, it is necessary to select a substance for the anti-adhesion layer that has greater affinity with the photosensitive layer than with the cover film. The substance constituting the anti-adhesive layer is not particularly limited as long as it does not impair the photosensitive properties of the system, and it may be a single substance or a mixture. Further, in order to uniformly adhere the negative film to the surface of the anti-adhesion layer from which the cover film has been peeled off, the surface of the anti-adhesion layer must be non-adhesive. The term "non-adhesive" here means that the initial peel strength described later is 5 g/cm (5 g/cm).
A value less than 100 times repeated average value is considered to be ``adhesive.'' Furthermore, it is important that the anti-adhesive layer be quickly dissolved and removed by a developing solution for the photosensitive layer during development after exposure to actinic rays through the negative film.
Insufficient solubility in the developer may cause uneven development of the photosensitive layer. Examples of substances constituting the anti-adhesive layer that satisfy the above conditions include cellulose, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyethylene oxide, polyvinylidene chloride, polyethyleneimine, and derivatives thereof. Among these, materials with oxygen permeability of 50 c.c./cm2.24 hr.atm or less, preferably 30 ^c.c./cm2.24 hr.atm or less are preferred,
Examples of substances with low oxygen permeability include polyvinyl alcohol and copolymers thereof, polyvinylidene chloride and copolymers thereof. Further, the thickness of the anti-adhesive layer is not preferable because if it is too thick, the reproducibility with negative film will deteriorate, and the appropriate thickness is 0.05 to 20 .mu.m, particularly preferably 0.1 to 5 .mu.m. Furthermore, it is a matter of course that the anti-adhesive layer is required to be transparent to actinic rays. The method for interposing the anti-adhesive layer between the cover film and the surface of the photosensitive layer is not particularly limited, and any method can be used. For example, a method in which a cover film is laminated after coating the anti-adhesive layer components on the surface of the photosensitive layer, a method in which a cover film coated with an anti-adhesive layer in advance is laminated on the surface of the photosensitive layer, or a method in which the cover film, the anti-adhesive layer, and the photosensitive layer are laminated on the surface of the photosensitive layer. There is a method to laminate both at the same time. As mentioned above, the cover film is intended to protect the surface of the photosensitive layer by preventing damage to the surface of the photosensitive layer, adhesion of dust and dirt, adsorption of dirt, moisture, etc., and can be made of well-known materials such as polyester film. In the present invention, a polyester film having a thickness of 10 μm or more is preferable. In order to prevent peeling at the interface between the cover film and the anti-adhesive layer when cutting the resin base plate, the peel strength between the cover film and the anti-adhesive layer must be 30 g/cm or more, and less than 30 g/cm The cover film peels off, making it impractical. Therefore, it is necessary to improve the peel strength by corona discharge treatment or the like. However, in the present invention, the peel strength between the anti-adhesive layer and the photosensitive layer is 50 g/cm higher than the peel strength between the anti-adhesive layer and the cover film.
If the difference is less than 50 g/cm, there may be an inconvenience that the anti-adhesive layer will peel off from the photosensitive layer together with the cover film when the cover film is peeled off. When a polyester film is used, it is particularly preferable that the surface tension of the surface in contact with the anti-adhesive layer is 42 dynes/cm or more, preferably 45 dynes/cm or more. In general, the components that make up the photosensitive layer include a filled polymer, a photocuring agent, a photosensitizer, a polymerization inhibitor, and other additives. , polyurethane type, polyvinyl alcohol type, polyester type, polyvinyl acetate type, etc.
The present invention may be applied to any known photosensitive layer and is not particularly limited. In the present invention, it is not necessary to provide an adhesive layer for adhering the photosensitive layer and the support, and the adhesive property thereof may also have an antihalation function. Further, as the support, any material such as steel, aluminum, plastic film, glass, etc. can be used. Furthermore, conventionally known methods can be applied to the production of the resin base plate. Examples include a hot press method, a casting method, a solution casting method, and a melt extrusion method. As described above, since the laminate of the present invention has a novel anti-adhesive layer, it has the following various features. That is, since a non-adhesive anti-adhesion layer is laminated on the surface of the photosensitive layer, the negative film can be easily adhered to the photosensitive layer, and air can be removed evenly and evenly. In particular, when the surface hardness of an uncured resin plate, such as a photosensitive resin plate for flexographic printing, is extremely low, deformation of the resin surface (local irregularities, uneven thickness, However, in the laminate of the present invention, there is no need to apply particularly strong pressure to adhere the negative film, and the surface of the resin plate is not damaged. Further, since the negative film is not in direct contact with the surface of the photosensitive layer having adhesive properties, the negative film can be easily peeled off after exposure, and there is no staining of the negative film. Also, there is no dirt on the cover sheet for the presser foot when the printer is vacuumed. Furthermore, by using a cover film whose surface activity has been improved by corona discharge treatment, it is possible to effectively prevent the cover film from peeling off when cutting the resin base plate. In addition, by using a substance with low oxygen permeability as a component of the anti-adhesion layer, the sensitivity is high, the degree of decrease in sensitivity over time is reduced, and stable plate-making performance can be maintained. The curability upon exposure to light is improved, the development latitude is widened, and the sensitivity does not decrease for a long time even after the cover film is peeled off. The laminate of the present invention can be effectively used for various purposes such as relief plates for printing, decorative designs, name plates, displays, and molded products. Next, the present invention will be specifically explained using Examples, but the present invention is not limited thereto. Note that surface tackiness, peel strength, and surface tension were measured by the following methods. Surface adhesion: A test piece (width 3 cm) with a negative film adhered to the surface under pressure is mounted horizontally on the test stand, and the negative film is peeled off in advance at a width of 1 cm from one end of the test piece and a crease is made at right angles. .
Next, a load is applied to one end, and the weight required for the tightly attached film to peel off (initial peel strength)
is displayed as sticky. Peel strength: Mount a test piece (width 1 cm) horizontally on a test stand, peel off the anti-adhesive layer in a 1 cm width from one end of the test piece, and make a crease at a right angle. Next, a load is applied to this one end, and the weight required for the anti-adhesive layer to peel off from the cover film or the surface of the photosensitive layer is expressed as the peel strength. Surface tension: According to the method of JIG-K-6768. Example 1 Water-developable photosensitive resin letterpress material whose photosensitive layer is based on polyamide resin, Toyobo Printite (SF-95)
The following comparative tests were conducted on types: cover film: 125μ, polyester film, photosensitive layer thickness: 742μ, adhesive and antihalation layer: 20μ, base film: 188μ polyester film. Here, sample (A) is the normal route product, sample (B) is the thickness between the cover film and the photosensitive layer.
1μ Gohsenol AH-26 [Nippon Gosei Chemical Industry Co., Ltd.
Co., Ltd. with a layer of polyvinyl alcohol with a degree of saponification of 97.0 to 98.8 mol%. Sample (C) is a polyester film whose contact surface with the layer of Gohsenol AH-26 has been treated with corona discharge as a cover film. Same as sample (B) except that . Sample (D) was the same as sample (C) except that methylcellose was used as the anti-adhesive layer, and sample (E) was the same as sample (D) except that the degree of corona discharge treatment was weakened. Table 1 shows the sample conditions and test results.

[Table] As is clear from Table 1, samples (B) and (C), which are the laminates of the present invention, provided images with no uneven relief halftone dots, and also had excellent stability over time. In the sample (A) without an anti-adhesion layer, the air between the photosensitive layer and the negative film did not escape, resulting in uneven halftone dots in relief. In addition, in sample (D), when the cover film was peeled off, the anti-adhesion layer was partially peeled off from the resin surface together with the cover film, resulting in uneven halftone dots in relief. Similar to sample (B), the cover film of sample (E) peeled off during cutting. Example 2 Reaction of 100 parts of copolyamide obtained by polycondensing 120 parts of ε-caprolactam, 90 parts of hexamethylene diammonium adipate, and 120 parts of hexamethylene diammonium sebacate, 85.2 parts of glycidyl methacrylate, and 18.4 parts of glycerin. 80 parts of product, 2 parts of benzoin methiether, 0.2 parts of hydroquinone monomethyl ether and 400 parts of methanol
After removing methanol by air-drying in a dark room at room temperature, the mixture was further dried under reduced pressure at 40°C overnight to obtain a uniform transparent sheet of the photosensitive composition. A portion of this was sandwiched between a steel plate coated with an adhesive and a polyester film, and the three were heated and laminated to obtain a photosensitive original plate (referred to as sample (F)). Separately, the surface tension of the coated surface is reduced by corona discharge treatment.
46.1 dyne/cm polyester film with alcohol-soluble copolyamide polyamide〓UItvamid−
The rest of the photosensitive resin sheet was sandwiched between a cover film coated with approximately 2μ of IC (manufactured by BASF) (so that the coated surface was in contact with the photosensitive layer) and a steel plate coated with adhesive, and heated and laminated. A photosensitive original plate (referred to as sample (G)) was prepared. Next sample
The polyester film serving as the cover film for both (F) and (G) was peeled off, a negative film was vacuum-adhered to the surface of the photosensitive layer (the polyamide layer in the case of (G)), and the film was exposed to light using a chemical lamp for 5 minutes. Then, it was washed out with menol in a brush developing machine for 3 minutes to obtain a relief plate. The halftone area of this relief version is a sample.
In the case of (G), it was uniform and faithfully reproduced the negative film, but in sample (F), uneven printing occurred due to uneven adhesion, and the reproducibility with respect to the negative film was poor. The adhesiveness of the surface before applying the negative film is 145 g/cm for sample (F) and 2 for sample (G).
g/cm. Further, the peel strength between the anti-adhesive layer and the cover film of sample (G) was 85 g/cm, and that between the photosensitive layer was 180 g/cm or more.

Claims (1)

[Claims] 1 At least from the upper layer: (1) cover film, (2)
In a photosensitive resin laminate for making a solid relief mold, which is composed of a photosensitive layer and (3) a support, (1) a cover film is subjected to a corona discharge treatment, and the gap between the (1) cover film and (2) the photosensitive layer is is soluble in the developer of the photosensitive layer, and has a peel strength with the photosensitive layer that is at least 50 g/cm higher than an isolation strength with the cover film;
A photosensitive resin laminate for making a solid relief mold, characterized by interposing an anti-adhesive layer having a peel strength of 30 g/cm or more with respect to a cover film.