JPH0328699B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photosensitive resin intaglio material with improved ink transfer properties.

In gravure printing using intaglio materials, ink is first applied to the entire surface of the plate, the ink adhering to the plate is scraped off with a doctor knife, the ink is retained only in the recesses, and the ink in the recesses is transferred to the substrate. It has been implemented since then.

Further, as a modification of gravure printing, curved surface printing called tampo printing or tacho printing is performed. Similar to gravure printing, ink is placed all over the surface of the intaglio plate, scraped off with a doctor knife to retain the ink in the recesses, and then transferred to the surface of a flexible pad such as silicone rubber. This is gravure dry offset printing, which transfers ink by pressing the ink-applied surface of the pad onto a curved printing material, and allows printing to be sharper and more reproducible than screen printing. be.

These gravure plates are manufactured by carving plates or cylinders made of metals such as copper and iron to form recesses, or by etching using ferric chloride solution. There is.
Among these methods, the engraving method requires a high level of skill as a handicraft, while the etching method has the drawbacks that, in addition to the pollution prevention treatment of waste liquid, it is difficult to control the depth of the recesses and it takes a long time to make the plate. In order to improve these drawbacks, a net gravure method using photosensitive resin has been proposed (for example, Japanese Patent Laid-Open No. 52-32704).
This is a method in which the unexposed areas are completely eluted with a developer using normal plate making to form recesses, and the process is simple and has the advantage that plates of constant quality can always be obtained. However, when the above-mentioned plate material is used for actual printing, problems arise in that ink does not easily escape from the recesses, the amount of ink transferred is insufficient, and the ink is non-uniform. This is because the bottom surface of the recess is the surface of the support which has been subjected to adhesive treatment, and the affinity of the ink to this surface is excessive. That is, when a photosensitive resin is provided on a metal such as iron or aluminum or a plastic such as a polyester film used as a support, the surface of the support must be adhesively treated to increase adhesive strength. This treatment includes zinc phosphate treatment for iron, graining treatment and anodic oxidation treatment for aluminum, and surface matting treatment and corona discharge treatment for plastics, either alone or in combination. Although this treatment improves the adhesion with the photosensitive layer, it also dramatically improves the ink wetting, and the ink retention on the bottom of the recesses of the plate material is too strong, causing it to leak from the recesses to the printing substrate or pads for tacho printing. The transferability of the ink becomes significantly worse. In addition, when an adhesive layer is formed on the surface of the support, the bottom surface of the concave part of the plate material is an adhesive layer, and since the molecular cohesive force of the adhesive component is relatively small, when it comes into contact with ink, it is exposed to ink vehicle and solvent. This causes swelling and deformation of the recesses, and in addition to excessive ink retention, the transferability of the ink becomes extremely poor, and printing of a predetermined amount may not be able to be completed.

The inventors of the present invention have conducted extensive studies on improving the durability and ink transfer properties of intaglio plates using photosensitive resins, and have found that the specific configuration of the present invention is effective.

The structure of the present invention is as follows: (1) A support with a thickness of 5 to 5
In a photosensitive resin intaglio material formed by laminating photosensitive resin layers of 100 μm, a resin having an affinity with the resin forming the photosensitive resin layer is used between the support and the photosensitive resin layer. 1. A photosensitive resin intaglio printing material, characterized in that an ink transfer layer is provided, and a surface of the ink transfer layer in contact with the photosensitive resin is hardened by three-dimensional crosslinking.

(2) The photosensitive resin intaglio material as described in (1) above, wherein the ink transfer layer has a thickness of 2 to 100 μm.

(3) The photosensitive resin intaglio plate according to (1) above, wherein both the photosensitive resin layer and the ink transfer layer are made of a polyamide polymer composition, and the ink transfer layer is cured by three-dimensional crosslinking. Material.

(4) The photosensitive resin intaglio material according to (3) above, wherein the polyamide polymer composition contains 20 to 90% by weight of the polyamide polymer.

(5) The photosensitive resin layer according to (1) above, wherein both the photosensitive resin layer and the ink transfer layer are made of a saponified polyvinyl acetate composition, and the ink transfer layer is cured by three-dimensional crosslinking. Resin intaglio material.

(6) The photosensitive resin intaglio material as described in (1) above, wherein the ink transfer layer is a resin layer formed of a photosensitive resin composition and photocured.

It is in.

An embodiment of the photosensitive resin intaglio material of the present invention will be explained using drawings. In FIG. 1, 1 is a support, on the surface of which there is a layer 1' which has been subjected to an adhesive treatment. 2 is an ink transfer layer which is a feature of the present invention, and 3 is a photosensitive resin layer. In FIG. 2, numeral 3' is a recess forming layer obtained by changing the photosensitive resin 3 of FIG. 1 by plate making, and the bottom surface of the recess is an ink transfer layer.

A positive film is closely attached to the photosensitive resin intaglio material having a laminated structure of the present invention and exposed to actinic rays, and then the unexposed areas are completely removed with a photosensitive resin solvent until the surface of the ink transfer layer is exposed. A recess with a constant depth is formed by this. Similar to the recess forming layer 3', the surface of the ink transfer layer 2 is highly three-dimensionally crosslinked during curing to the extent that it is not attacked by the developing solvent, so it does not swell with ink.
In addition, since the composition is similar to that of the concave forming layer that has improved ink transfer properties as an intaglio material, the amount of ink transfer is sufficient, and the uniformity and stability of the amount of transfer during long-term printing is also good. be. In this respect, it is far superior to photosensitive resin intaglio materials that do not have an ink transfer layer.

The photosensitive resin layer used in the present invention includes various base polymers mixed with photopolymerization components, photosensitizers, heat stabilizers, plasticizers, and the like.

Base polymers include fully saponified polyvinyl acetate, partially saponified polyvinyl acetate, partially saponified polyvinyl acetate modified with ethylene oxide, partially saponified vinyl acetate-ethylene copolymer, solvent-soluble polyamide, water-soluble polyamide, and polyether. Examples include cellulose derivatives such as esteramide, methyl cellulose, ethyl cellulose, and hydroxyethyl cellulose, and solvent-soluble polyester resins. Polyamides and partially saponified polyvinyl acetate exhibit good ink transfer properties and resistance to doctor knives for ink scraping. Preferred are soluble polyamides, and more preferred are water and lower alcohol soluble polyamides.

Any photopolymerizable component can be used as long as it has an ethylenically unsaturated bond in its molecule and is compatible with the base polymer.

As the photosensitizer, all conventionally known sensitizer systems such as benzophenone type, benzyl type, acetophenone type, benzoin alkyl ether type, and anthraquinone type can be used.

All conventionally known components such as heat stabilizers, plasticizers, surfactants, ultraviolet absorbers, dyes, and pigments can be added.

The content of the base polymer in the photosensitive resin can be arbitrarily adjusted in consideration of the sharpness of the cross-sectional shape of the recesses in the recess-forming layer, the sensitivity to actinic rays, and the like. In the case of polyamide-based composite compositions,
It is necessary to contain the polyamide polymer in an amount of 20 to 90% by weight. If it is less than 20% by weight, the recess forming layer lacks flexibility and cracks are likely to occur. 90% by weight
Above this, the sensitivity is low and the cross-sectional shape of the recesses lacks sharpness, making it impossible to obtain printed matter with good reproducibility.

The ink transfer layer of the present invention is a resin layer obtained by blending a polymerization component, a polymerization initiator, a stabilizer, a plasticizer, etc. with various base polymers, and then curing the mixture by conventionally known methods such as heating and irradiation with actinic rays. The base polymer and polymerization initiator may be exactly the same as those used for the photosensitive resin layer, or even if they are different, this ink transfer layer after curing can be easily connected to the photosensitive resin layer without an adhesive layer. Any resin may be used as long as it provides a resin with high affinity to the extent that it can be firmly bonded. For example, it is preferable if the polymers in each layer are similar, such as the same solvent-soluble polyamide, because when a photosensitive resin layer is provided on the ink transfer layer, fusion adhesion between the polymers can be expected at the very interface between both layers. . When this ink transfer layer is a resin layer formed by photocuring a photosensitive resin composition, it is particularly suitable from the viewpoint of production efficiency because the same raw materials and composition can be used.

The support in the present invention may be made of metal or non-metal such as plastic, wood, glass, or ceramics, and may have a plate-like or cylindrical shape. The metal material is preferably iron or aluminum, and the non-metal material is preferably plastic such as polyethylene, polypropylene, polyvinyl chloride, or polyester. When the support is in the form of a plate, polyester films are preferred from the viewpoint of dimensional stability and flexibility, and in particular polyester films with appropriate rigidity.
Most preferred is a 400 μm polyethylene terephthalate film.

Adhesion treatment on the surface of these supports can be carried out by conventionally known methods. Examples include graining treatment for aluminum and matting treatment for plastic. In order to obtain sufficient adhesion force, it is preferable to use a method of adhesion via an adhesion treatment layer 1' shown in FIG. 1, the composition of which is appropriately determined based on the materials of the support and the ink transfer layer. As adhesive layer components, epoxy systems and phenolic resin systems are generally used for metals, and polyurethane systems, polyester systems, polyvinyl acetate systems, etc. are used alone or in combination for plastics. The adhesive treatment layer can be provided on the surface of the support by any method.

In order to provide an ink transfer layer on a support that has been subjected to such an adhesive treatment, if the support is in the form of a plate, a solution of an uncured ink transfer layer composition dissolved in an appropriate solvent can be applied by spraying, using a roll coater, A possible method is to uniformly apply the film to a predetermined thickness using a slit die coater or the like, and then remove the solvent using a drying device. In the case of a cylindrical support, examples include a method in which an uncured composition solution is uniformly coated on a rotating cylindrical support using a slit die coater and then dried. In order to increase the accuracy of the coating film thickness, it is also possible to polish or cut the surface after drying or curing.

The uncured ink transfer layer can be cured by appropriate heat treatment if the resin of the ink transfer layer is a thermosetting type, or by using an ultraviolet exposure device such as an ultra-high pressure mercury lamp or a chemical lamp if it is a photocuring type. This can be done by In the case of an electron beam sensitive type, electron beam irradiation is also possible, and another example is curing by chemical treatment such as insolubilization of partially saponified polyvinyl acetate with glyoxal. The degree of curing is determined by the fact that the photosensitive resin is not eluted by the developing solvent and that it does not undergo deformation such as swelling due to the ink used.

The thickness of the ink transfer layer must be in the range of 2 to 100 μm. That is, if the thickness is less than 2 μm, the ink solvent will penetrate and reach the adhesive treatment layer on the surface of the support, causing a decrease in adhesive strength and deformation of the adhesive layer.
If the thickness is 100 μm or more, problems such as curling and deformation of the plate material due to curing shrinkage and cracks will occur. More preferably, it is in the range of 4 to 70 μm.

The method for providing the photosensitive resin layer on the ink transfer layer can be the same method as in the case of providing the ink transfer layer on the support.

The thickness of the photosensitive resin layer needs to be within the range of 5 to 100 μm. If it is less than 5 μm, the depth of the recesses is insufficient and the ink in the recesses will be scraped off with a doctor knife. If the thickness is 100 μm or more, incurring may occur during plate storage and cracks may occur when installing the cylinder. More preferably 7
~80 μm.

It is also possible to mount a suitable cover film on the surface of the photosensitive resin layer for protection. As such a film, polyester film, polypropylene film, polyethylene film, etc. can be used, but polyester film is preferred from the viewpoint of dimensional stability and oxygen barrier properties, and polyethylene terephthalate film is most suitable. Furthermore, if the surface of these films is matted, the matte shape is transferred to the plate surface, making it easy to vacuum-adhere the positive film during plate making. Of course, it is also possible to use the device without attaching these cover films.

The thus obtained photosensitive resin intaglio material, which has an ink transfer layer interposed between the support and the photosensitive resin layer, can be easily used for gravure printing and curved surfaces by plate making that involves ordinary exposure and development steps. It can be a printing plate for printing.

A more specific explanation will be given below using Examples and Comparative Examples.

Example 1, Comparative Example 1 Copolyamide "Ultraamide-1C" manufactured by BASF, which is an alcohol-soluble polyamide, was used as the base polymer, ethylene glycol diglycidyl ether dimethacrylate and triacrylic formal were used as photopolymerizable monomers, and benzoinmethyl A 40% (by weight) ethanol solution of a photosensitive resin was prepared using ether as a photosensitizer and t-butylcatechol and triphenylphosphine as heat stabilizers.

This solution was cast onto a polyester film (thickness: 250 μm) on which a polyester adhesive had been applied in advance to a thickness of 30 μm so that the film thickness after drying would be 30 μm. This was placed in an oven at 100°C for 5 minutes to completely remove the solvent. In this way, an uncured ink transfer layer was formed that was adhered to the polyester film via the adhesive layer, and the entire surface of the uncured ink transfer layer was irradiated with ultraviolet rays from a high-pressure mercury lamp in the air for 2 minutes. Through the exposure treatment, at least the entire surface of the uncured ink transfer layer was three-dimensionally crosslinked and cured to form an ink transfer layer. It was confirmed that by performing such exposure, the ink transfer layer was not dissolved or swollen by alcohol at all.

Next, as a photosensitive resin composition on the ink transfer layer, 0.02% by weight of "Direct Sky Blue" (manufactured by Sumitomo Chemical Co., Ltd.) as a dye was added to the same composition solution as the uncured ink transfer layer. A solution was prepared. This solution has a thickness of 30 μm after drying.
It was cast and dried in an oven at 100°C for 5 minutes.

In this way, a 30 μm thick ink transfer layer and a 30 μm thick ink transfer layer lined with a polyester film
A photosensitive resin intaglio material having a laminated structure consisting of a photosensitive resin layer was obtained.

For comparison, a photosensitive resin composition was cast onto a substrate having a 30 μm thick polyester adhesive layer provided on the same 250 μm thick polyester film so that the dry thickness would be 30 μm. The solvent was removed by placing it in an oven at 100° C. for 5 minutes to obtain a photosensitive resin intaglio material having no ink transfer layer.

A positive film for curved surface printing consisting of Mincho characters with a line width of 50 to 200 μm and independent points with a diameter of 50 to 300 μm was vacuum-adhered onto these plates, and exposed to light using a chemical lamp for 4 minutes. After that, ethanol/
It was developed using a brush type washing machine containing a mixed solvent of water = 80/20 (weight ratio). The development was completed when the blue color of the dye in the unexposed areas completely disappeared. Thereafter, it was dried in an oven at 50°C for 10 minutes, and then post-exposed to a chemical lamp for 2 minutes. The plate surface hardness was Shore D65.

The thus obtained intaglio material was adhesively fixed to the printing plate of a pad printing machine "Model T-15" manufactured by Taihei Kogyo Co., Ltd. using double-sided tape. Next, Dainippon Ink Co., Ltd. was applied to the entire surface of the intaglio.
A small amount of solvent (isophorone) was added to the ink for making screens to reduce its viscosity, and at the same time, the ink on the plate was removed with a doctor knife using a squeegee. Next, the concave image was transferred onto a silicone rubber pad (Shore A hardness: 6), and finally printed on the curved surface of an ABS resin gas lighter.

Comparing the obtained printed matter, it was found that the photosensitive resin intaglio material having the ink transfer layer according to Example 1 of the present invention was extremely sharp, and the amount of ink transfer was uniform and sufficient. It was found that the conventional photosensitive resin intaglio material without the ink transfer layer of Example 1 had an insufficient amount of ink transfer overall, and moreover, the transfer was partially uneven. When the cause of this was investigated, it was found that the adhesive layer on the polyester film substrate was swollen by the ink. It was also confirmed that those having an ink transfer layer had good ink removal because they were not swollen by ink at all.

Thus, it has been found that the photosensitive resin intaglio material having an ink transfer layer is excellent as a printing plate material for curved surfaces.

Example 2 A partially saponified polyvinyl acetate photosensitive resin with a degree of saponification of 75 mol% and a degree of polymerization of 600 was selected as the base polymer on a polyester film substrate pre-coated with the same polyester adhesive as in Example 1. After dissolving in a mixed solvent of ethanol/water = 50/50 (weight ratio), a small amount of glycidyl methacrylate was added and stirred at 80°C for 1 hour to dissolve the carboxylic acid and glycidyl methacrylate present at the ends of the partially saponified polyvinyl acetate polymer. A methacryloyl group was introduced into the polymer by reacting the epoxy ring.

Next, propylene glycol diglycidyl ether diacrylate was used as a photopolymerizable monomer, dimethylbenzyl ketal was used as a photosensitizer, and diethylene glycol was added as a plasticizer, and the resulting solution was thoroughly mixed and stirred to determine the thickness after drying. is 20μm
It spread like this. After placing this in an oven at 100℃ for 5 minutes to completely remove the solvent, the entire surface is exposed to ultraviolet light from a high-pressure mercury lamp for 1 minute in a nitrogen stream to three-dimensionally crosslink and harden the entire surface, resulting in sufficient water resistance. An ink transfer layer having the following properties was formed.

On this ink transfer layer, a solution of the same composition as the uncured ink transfer layer was cast so that the thickness after drying was 60 μm, and the solution was dried in an oven at 100° C. for 15 minutes. In this way, a photosensitive resin intaglio material having a laminated structure was obtained.

After vacuum-adhering the same positive film for curved surface printing as in Example 1 onto this plate material, it was
After exposure for one minute, development was carried out using a spray developing machine containing neutral water until the lower layer surface of the unexposed area was completely exposed. Thereafter, it was placed in an oven at 60°C for 1 minute to thoroughly dry it.

The thus obtained intaglio material for printing on curved surfaces was subjected to a printing test under the same printing conditions as in Example 1. The results showed that it was possible to print very sharply, with sufficient and uniform ink transfer, and that the adhesive strength of the photosensitive resin layer was also sufficient.

Example 3 Spray epoxy adhesive on the surface of an iron cylinder with a circumference of 30 cm and a width of 60 cm to a thickness of approximately 5 μm.
Cure was carried out for 2 minutes at ℃.

As an uncured ink transfer layer composition, N-methoxymethylated nylon 6 (methoxymethylation rate of about 34 mol%) is used as a base polymer, and ethylene glycol diglycidyl ether diacrylate and triacryl formal are used as photopolymerizable monomers. In combination, benzophenone was used as a photosensitizer to prepare an ethanol solution with a solute concentration of 30% (weight).

This solution was applied to a 60mm wide steel cylinder installed above the previously obtained epoxy adhesive coated steel cylinder.
cm, 12 per minute from a slit die with a lip spacing of 20 μm
A photosensitive resin layer with a thickness of 50 μm was formed by casting onto the surface of a rotating cylinder and drying by blowing hot air at 50° C. while rotating at 20 revolutions per minute. Thereafter, the entire surface was three-dimensionally crosslinked and photocured by irradiating it with ultraviolet rays from a high-pressure mercury lamp for 2 minutes while rotating in the air until it no longer swelled with ethanol, thereby forming an ink transfer layer.

When the photosensitive resin intaglio material according to the present invention is made into an intaglio material having recesses by exposing the photosensitive resin layer on the surface and eluting and removing the unexposed portions with a developing solvent such as a mixture of ethanol/water. The bottom surface of the recess is formed in advance by an ink transfer layer that is three-dimensionally crosslinked and cured during the process of manufacturing the photosensitive resin intaglio material, and has sufficient water resistance. Forms an extremely smooth surface without deterioration during exposure and elution and removal of non-exposed areas.

Furthermore, the bottom surface of the recess made of the ink transfer layer does not swell with ink during printing and can withstand long-term and large amounts of printing, and the ink drains well and the resulting printed matter is clear and high-quality. Becomes quality.

On this cylindrical ink transfer layer, a photosensitive resin solution having the same copolyamide as the base polymer as in Example 1 was cast in the same manner as the uncured ink transfer layer, and dried to form a photosensitive resin with a thickness of 40 μm. A synthetic resin layer was formed.

A mesh positive film having 85 lines was vacuum-adhered onto the cylinder-shaped photosensitive resin intaglio material thus obtained, and exposed for 5 minutes with a chemical lamp. Thereafter, development was performed using a spray type developer containing a mixed solvent of ethanol/water = 80/20 (weight ratio) until the photosensitive resin layer in the image area was completely removed. In this way, a mesh gravure cylinder with a constant recess depth of 40 μm could be obtained.

When a printing test was conducted using this plate material, very sharp printed matter with sufficient and uniform ink transfer properties was obtained. It was also found that the adhesive strength of the photosensitive resin layer was sufficient and that it had practically sufficient printing durability.

[Brief explanation of the drawing]

The drawings are cross-sectional views showing one embodiment of the photosensitive resin intaglio material according to the present invention, and FIG. 1 shows the state before recesses are formed on the plate surface, and FIG. 2 shows the state before recesses are formed on the plate surface. Indicates the state of DESCRIPTION OF SYMBOLS 1...Support, 1'...Adhesion treatment layer, 2...Ink transfer layer, 3...Photosensitive resin layer, 3'...Recess forming layer.

Claims (1)

[Scope of Claims] 1. On a support whose surface has been subjected to adhesive treatment,
In a photosensitive resin intaglio material formed by laminating photosensitive resin layers of 100 μm, a resin having an affinity with the resin forming the photosensitive resin layer is used between the support and the photosensitive resin layer. 1. A photosensitive resin intaglio printing material, characterized in that an ink transfer layer is provided, and a surface of the ink transfer layer in contact with the photosensitive resin is hardened by three-dimensional crosslinking. 2. The photosensitive resin intaglio material according to claim 1, wherein the ink transfer layer has a thickness of 2 to 100 μm. 3. The photosensitive resin intaglio plate according to claim 1, wherein both the photosensitive resin layer and the ink transfer layer are made of a polyamide polymer composition, and the ink transfer layer is cured by three-dimensional crosslinking. Material. 4. The photosensitive resin intaglio material according to claim 3, wherein the polyamide polymer composition contains 20 to 90% by weight of a polyamide polymer. 5. The photosensitive resin layer according to claim 1, wherein both the photosensitive resin layer and the ink transfer layer are made of a saponified polyvinyl acetate composition, and the ink transfer layer is cured by three-dimensional crosslinking. Resin intaglio material. 6. The photosensitive resin intaglio material according to claim 1, wherein the ink transfer layer is a resin layer formed of a photosensitive resin composition and photocured.