JPS60139482A - Waterless planographic printing base plate - Google Patents

Abstract

PURPOSE:To prevent a continuous feed obstruction by avoiding surface stickiness without damaging image reproducibility and printing quality, by providing unevenness with specific roughness to the surface of the rubber elastic layer on a support. CONSTITUTION:Unevenness of which the center line average roughness Ra is 0.2-1.0mum and the ten-point average roughness Rz is 0.5-10mum is provided to the surface of the rubber elastic layer on a support having rubbery elasticity. The center line average roughness Ra of the rubber elastic base material for a waterless planographic plate material must not exceed 10mum and the ten-point average roughness Rz must not exceed 10mum. The waterless planographic plate material using a rubber elastic base material with rougheness exceeding said numerical values is inferior to image reproducibility because the projections of the surface of said base material are not sufficiently covered by a plate constituting element and a pattern faithful to an original can not be obtained. The upper limit of especially pref. surface roughness is 0.5mum in Ra and 5mum in Rz. On the other hand, the lower limit of the unevenness of the rubber elastic base material is determined from the point of surface stickiness and 0.2mum or more in Ra and 0.5mum or more in Rz.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a waterless lithographic plate using a base material having rubber elasticity, and is particularly characterized in that minute irregularities are formed on the surface of the base material. This relates to waterless planographic materials.

Prior Art Waterless lithographic materials using silicone rubber are known2. For example, those using fluorine compounds are Kaisho 51 + 5
Many proposals have been made, including No. 8105.

Waterless lithography using a base material with rubber elasticity has also been proposed in JP-A-56-78991 and JP-A-57-22242, etc., and excellent printed matter with a thick ink film, especially in direct printing, has been proposed. It is known that it can be obtained, and it is used for applications such as printing on printed wiring boards.

A base material with rubber elasticity used for such plate materials!
:L, Teha, nitrile rubber, chloroprene rubber.

The above-mentioned known examples disclose that thermoplastic elastomers such as polyetherester elastomers can be used in addition to vulcanized rubbers and polyurethane rubbers obtained from synthetic rubbers such as styrene rubber and natural rubbers. .

The properties required of these base materials include not only rubber elastic properties but also various properties as printing plate materials. For example, solvent resistance against ink and ink cleaning agents, morphological precision, and dimensional stability are required. Usually to ensure dimensional stability.

A plastic film or sheet or a metal plate is used as a support for the backing material of the elastomer.

The surface condition of the rubber elastic base material is also an important property.

It must have excellent smoothness and uniformity.

There should be no irregularities that would appear as defects in printed matter, and it is currently preferable that the surface of the substrate be mirror-like.

The properties required of a base material having rubber elasticity must satisfy not only the final use as a printing plate but also the properties required during the production of a single plate material. Solvent resistance and drying properties for coating liquids applied to rubber elastic substrates.

Heat resistance that can withstand curing conditions is required. In particular, when the coating process is carried out continuously while the rubber elastic base material is being conveyed by rolls, the tackiness of the two surfaces becomes a problem. When conveying continuous long objects, meandering cannot usually be avoided.

Therefore, if it deviates from the specified position due to meandering,
Detect it.

A device (EPC; edge position controller) is adopted that automatically moves the roll and adjusts the left and right tension to correct meandering. At this time, a slight amount of slippage occurs between the surface of the conveying roll and the surface of the rubber elastic base material, and the meandering is corrected. If this slippage were not present, the meandering would not stop and would increase.

Wrinkles may occur on the way, making smooth conveyance impossible.

Such conveyance failure due to surface tackiness also poses a problem in the molding process of rubber elastic base materials. This problem is well known in the molding process of rubber, and in order to solve this problem, it is widely practiced to sprinkle a protective powder such as talc on the surface. However, it is inappropriate to use the rubber thus obtained as a base material for waterless lithography according to the art for the following reasons.

Before applying the coating liquid, it is necessary to remove the adhesion-preventing powder from the two surfaces, but it is very difficult to completely clean and remove just the powder without scratching the rubber surface. Even if the primary particles of talc itself are fine powder,
The sprayed particles usually clump together, causing uneven dents on the rubber surface. The basic problem is the stickiness of the rubber surface after the talc has been removed. In order to convey the product, adhesion between the rubber surface and the roll surface cannot be avoided. In order to apply uniform tension to the comb and apply the coating liquid evenly.

This is because it requires a nip roll or a priddle roll.

Another way to avoid sticky surfaces is to cover and mold the rubber surface with release paper or canvas treated with silicone resin, and then transfer the irregularities to the surface. However, the rubber surface obtained in this way has rough irregularities and uneven irregularities.

It is unsuitable as a base material for printing plates for the purpose of precision printing, which is the subject of this technology. In particular, in the case of a waterless planographic material obtained from a rubber elastic base material with unevenness made using cloth, moiré development occurs depending on the image pattern, making it unusable.

As with the case of vulcanized rubber, the adhesiveness of thermoplastic elastomers increases as the two surfaces approach mirror surfaces, just as in the case of vulcanized rubber. These elastomers consist of a hard segment i and a soft segment in order to exhibit rubber elasticity, but the latter is made of an amorphous polymer with a low glass transition point, such as polytetramethylene glycol. It's for a reason.

In particular, when a plastic lastomer that is flexible and has good rubber elasticity is used to enhance the printing effect, the content of this soft segment is large, and the adhesiveness increases even more during molding and coating processes. Continuous transportation becomes difficult.

To prevent these adhesion, conventional techniques similar to those for vulcanized rubber can be applied, but the surface condition of the obtained substrate is inappropriate for the printing plate material targeted by this technique. The same is true.

OBJECTS OF THE INVENTION The present invention relates to surface characteristics of a rubber-elastic base material in a waterless planographic material using a rubber-elastic base material. More specifically, the present invention relates to a rubber elastic base material having surface properties that do not impair image reproducibility or print quality, avoid surface tackiness, and prevent continuous conveyance failure.

The object of the present invention is to provide a waterless planographic printing press using such a rubber elastic base material.

The (1G) of the present invention is a waterless lithographic printing plate plate using a support having rubber elasticity, and the rubber elastic layer surface ij'11 of the support has a centerline average roughness Ra of 02. ~1.0μ.

The gist thereof is a waterless lithographic printing plate precursor having irregularities with a ten-point average roughness RZ of 05 to 10 μm.

The ty and V configurations of the present invention will be specifically explained below.

As a method for forming irregularities on the surface of the base material, it is also possible to perform post-processing such as Zandoplast or puffing after manufacturing the base material, but a particularly preferred method is as follows.

During manufacturing and processing of the base material, the surface of the base material is covered with a plastic film having slight irregularities, and the irregularities are transferred and formed onto the surface of the base material.

The unevenness of the rubber elastic base material of the present invention must not impede two-image reproducibility or printing quality. That is, it is necessary that the surface of the base material be sufficiently uniformly covered by the plate constituent elements applied to the surface of the base material, and therefore there is an upper limit to the roughness of the irregularities.

However, it is difficult to completely express surface roughness.

Here, it is expressed by center line average roughness Ra and ten point average roughness Rz defined in JIS BO601'-1975.

Ra of the rubber elastic base material for waterless planographic material of the present invention is 1 p
Must not exceed m. Still, Rz must not exceed 10 μm. Waterless lithographic materials made of rubber elastic substrates with roughness exceeding these values may suffer from poor reproducibility of 9 strokes and 1 image because the protrusions on the surface of the substrate are not sufficiently covered by plate constituent elements. is inferior, and it is not possible to obtain a pattern that is faithful to the original. Particularly preferable upper limits of the surface roughness are 05 μm for Ra and 5 μm for Rz.

On the other hand, the lower limit of the unevenness of the rubber elastic base material is determined from the viewpoint of surface tackiness. It is 02 μm or more in Ra or 05 μm or more in R2.

In order to produce a rubber elastic base material having the above-mentioned surface roughness, a plastic film having the above-mentioned surface roughness is prepared, and the surface of the rubber elastic base material is covered with the plastic film during production of the rubber elastic base material. Most preferably, the unevenness is transferred to the surface of the rubber elastic base material.

For example, in the case of a rubber elastic base material made of vulcanized rubber, the rubber is rolled into a sheet using a calender, a plastic film having the above-mentioned irregularities is laminated on the surface, and the back surface is
After laminating an aluminum sheet coated with adhesive if necessary, it is wound up on a drum. 2 It is heated and vulcanized in a normal vulcanizing can, and the plastic film is peeled off to obtain the rubber elastic base material of the present invention. .

A typical method for molding rubber elastic base materials made of thermoplastic elastomer is melt extrusion, but in this case, the molten elastomer extruded from a molding die is completely cooled and solidified. To.

The rubber elastic substrate of the present invention can be produced by laminating a plastic film having the above-mentioned irregularities on the surface thereof and, if necessary, laminating a support on the back surface.

In this way, a plastic film with an uneven surface costs $
, the secondary benefit of the method of overturning and transferring that unevenness is! 8! It is possible to prevent the adhesion and mixing of various foreign substances that occur during manufacturing. In this sense, it is preferable to peel off the plastic film just before the subsequent coating process of the plate material components. What are the other benefits of using matte film?

Good air release during lamination and vulcanization.

It is possible to avoid flatness defects caused by air sagging that occurs when a plain film is used.

What is the selection of plastic film used here?

Of course, the surface roughness satisfies the above characteristics, but
It is necessary to consider the processing temperature and peel strength of the rubber elastic base material. The best plastic film that satisfies these conditions is a film based on polyolefin, especially polypropylene.

It can be used in the production of rubber elastic base materials made of nitrile rubber, chloroprene rubber, polyether ester elastomer, polyurethane rubber, etc.

Examples of the rubber elastic base material used in the present invention include materials such as nitrile rubber, chloroprene rubber, styrene-butadiene rubber, butadiene rubber, acrylic rubber, urethane rubber, polyester elastomer, and polyamide elastomer. The hardness of these rubber elastic bodies is preferably A hardness of 90 or less as defined in JIS K6 Ro01-1975.

More optimally, it is 85 or less. When a rubber elastic body with a JISA hardness exceeding 90 is used, the printing improvement effect is insufficient. The thickness of the rubber elastic body is usually about 0.001 to 5.00 mm.

In order to provide the dimensional stability and shape retention required for printing plates, the rubber elastic body is used by being backed with a metal plate such as an aluminum plate or iron plate, or a plastic film such as poly(ethylene telecrate). I can do it.

The basic technology of waterless lithography applied on the rubber elastic substrate of the present invention is already known.

As an example of providing a non-photosensitive silicone rubber layer on a photosensitive resin layer, Japanese Patent Publications No. 44-26042 and No. 46-16
044. Japanese Unexamined Patent Publication No. 1973 94503. JP-A-57-101
45 etc. can be given.

The photosensitive resin layer is a layer that has the property of being photo-insolubilized or photo-solubilized by irradiation with active light. This layer is uniformly formed directly on the rubber elastic substrate via an intermediate layer such as an adhesive layer.

Although the film thickness is arbitrary, it is usually 05 μm to 100 μm. The photosensitive resin layer must sufficiently cover the uneven surface of the rubber elastic base material. 2 if the coverage is incomplete
Image@Reproducibility will be incomplete. Generally speaking, when using a rubber elastic base material with small irregularities, the photosensitive resin layer may be thin, but in the case of a base material with large irregularities, it needs to be thick.

In the case of the base H having large irregularities, it is also effective to provide a coating layer in advance to compensate for the irregularities in order to make the photosensitive resin layer thinner.

A silicone rubber layer is provided as an ink repellent layer on this photosensitive resin layer, with an adhesive layer interposed therebetween if necessary.

provided.

An example in which the ink-repellent silicone rubber layer is the lower layer is disclosed in Japanese Patent Publication No. 47-2361, and an example in which the ink-repellent layer is a fluorine compound is disclosed in Japanese Patent Publication No. 44-28726. As an example of using a photosensitive silicone composition, Japanese Patent Publication No. 55-254
18. Examples include Special Publication No. 55-27337.

These examples can also be applied to the rubber elastic base material of the present invention.

An example of a method for manufacturing the base material ρ using a thermoplastic elastomer will be briefly described. In FIG. 1, a molten elastomer supplied from a melt extruder is formed into a sheet by a forming die 1, and a support 6 and a cover film 8 are laminated between a pressure roll 2 and a cooling roll B. cooled down. The base material 10 with the cover film attached or with the cover film peeled off at the position of the peeling roll 4 is finished into a roll shape by the winding roll 5.

An example of a coating process for producing a waterless planographic material by coating a photosensitive agent on a base will be briefly described. In FIG. 2, the base material 20 supplied from the second unwinding roll 11 is in a state in which, if it has a cover film, the cover film 19 is peeled off by the peeling roll 12, and the base material 20 is in close contact with the coating roll 1 due to tension. Then, the substrate is coated with the coating liquid supplied from the coating liquid supply layer 14, and a coating layer is formed on the substrate by a curing reaction of the desiccant in the heating furnace 15. If necessary, the protective film 21 is laminated by a pressure roll 16 and then by a two-winding roll 18.

It is wound up into a roll. At this time, the position of the end surface of the substrate is detected by the EPC 17, and the position of the two winding rolls 18 is adjusted in order to correct the position of the substrate 20 relative to the coating liquid supply head 14 and to align the end surfaces of the rolls to be wound. Fix it. By repeating these steps, a photosensitive layer and a silicone rubber layer are formed on the base material, and a waterless planographic material is manufactured.

Examples 1-2. Comparative Examples 1 to 4 A rubber elastic base material was molded using the extrusion laminator shown in FIG. 1, and a waterless lithographic plate material was produced on this base material using the coating equipment shown in FIG. 2.

A sheet having a thickness of 0.6 mm and made of a polyester elastomer obtained by polymerizing 1494 parts of terephthalic acid, 16.6 parts of inctal acid, and 381 parts of polytetramethylene glycol having a number average molecular weight of 100 in the presence of a titanium tetrabutoxide catalyst was extruded. The temperature of the extruder is approximately 210°C,
The Gui temperature was set at about 180'C, and the cooling drum was set at about 7'C. At this time, a 250μ thick polyethylene telescrate film ("Lumirror'250H") was removed from the pressure roll side.
10, Toshiku Co., Ltd. product) was inserted, and the cover film shown in Table 1 was inserted from the cooling drum side to create a rubber elastic base material.

Using the coating equipment shown in FIG. 2, a photosensitive liquid is applied to the rubber elastic base material obtained in this way from a coating liquid supply head.
Dry. The photosensitive resin was 0-naphthoquinone diazide-5-sulfonic acid ester of novolac type phenol resin, which was made into a 20% solution in the solvent ethyl cellosolve, dried at 100°C for 4.6 minutes, and the coating amount was 2. ~2.5
g/m2.

If there was no problem in transporting the rubber elastic base material and the photosensitive layer could be coated well, an adhesive layer and a silicone rubber layer were further coated nine times. The adhesive used was aminoethyltrimethoxylano, which was made into a 0.2% solution in a hydrocarbon solvent, Isopar E (Edge product).

Drying at 120°C for 06 minutes, coating amount is 0.04 g/m
It was set to be 2.

Silicone rubber is polymethylsiloxane with terminal hydroxyl groups (
A mixture of 100 parts of molecular weight (approximately 20,000), 6 parts of ethyltriacetoxysilane, and 0.12 parts of diptyltin dilaurate.
Apply 15% with Isopar "E" and apply 100'
The coating amount was set to 6 to 5 g/m 2 after 5 minutes of cx filter curing.

A negative film consisting of patterns of different line widths was closely adhered to the obtained waterless lithographic original plate, the patterns were printed by irradiation with a metal halide lamp, and a mixed solution consisting of 65 parts of alcohol and 35 parts of Isopar E was applied. Difficulty with a soaked cotton pad.

The sharpness of the pattern was observed using a 25x magnifying glass.

In Example 1, the winding appearance during molding is good, there is no pulsation when applying the photosensitive liquid, even if meandering occurs, it can be corrected within the RPC (edge position controller) tolerance range, and continuous conveyance is possible. The coating is ready.゛Photosensitive layer 2.5 g/m2. Silicone rubber layer 3 g/
The image reproducibility of the lithographic plate that did not require dampening water and was prepared under the conditions of m2 was good.

Similarly to Example 1, Example 2 was also able to perform conveyance coating well.

Photosensitive layer 2.5 g/m2. Silicone rubber layer 5g//m
The reproducibility of both edges of the waterless planographic plate prepared under the conditions of 2 was good.

In Comparative Example 1, since the surface of the rubber elastic base material had high tackiness, it pulsated when it was separated from the cooling drum during its production.
Horizontal stripes appear on the surface and still remain.

The one with a neat shape? 4I couldn't do it. When applying the photosensitive liquid, meandering could not be corrected and continuous conveyance and application were not possible.

In Comparative Example 2, the adhesive force between the polyester film used for the cover film and the rubber elastic body was too strong to be peeled off.

In Comparative Example 6, after the cover film was peeled off, the surface of the rubber elastic body was highly sticky and the two-wrap appearance was poor.

Even when applying the photosensitive liquid, it pulsated and meandering by 2 inches could not be corrected, making continuous conveyance and application impossible.

Comparative Example 4 was also the same as Comparative Example 6.

Examples 5-4. Comparative Example 5-B "Lumirror" in which NBR (trill rubber) containing various compounding agents was rolled in an inverted calendar and formed into a sheet with a thickness of 025 m, while an adhesive was applied to one side of the rubber sheet. 25DHIO was laminated with a cover film shown in Table 2 on the other side.

It was wound up on a vulcanizing drum, placed in a vulcanizing can heated with steam, and heated and vulcanized at 120 to 160°C for 3 hours. This was re-wound onto the paper tube while being rewound.

About the rubber elastic base material thus obtained.

A photosensitive liquid was applied in the same manner as in Example 1 while peeling off the cover film. For those on which the photosensitive layer was well coated, an adhesive layer and a silicone rubber layer were further coated to prepare a waterless planographic plate, which was exposed and developed, and the resulting image was evaluated.

The rubber elastic base material of Example 6 could be transported smoothly during coating. Even if meandering occurred, it could be corrected to within the allowable range using EPC. The image reproducibility of the waterless planographic plate prepared under the conditions of photosensitive layer 2: 5 g/m2 and silicone rubber layer: 5 g/m20 was good.

Similar to Example 4, Example 4 also had good substrate conveyance and good image reproducibility.

In Comparative Example 5, there were no transportation problems and the coating process was successful, but 9
The image was bad. This seems to be because when rubbing with a pad during development, the photosensitive layer in the non-image area is rubbed off along with the Merc adhering to the rubber surface.

In addition, there were two localized areas where talc aggregated, causing two images to be damaged.

Prior to application, Merck was washed and removed. It was cleaned with running water and a rotating brush using a modified automatic developing machine for water-filled lithography, but the rubber surface and talc were too sticky and could not be completely cleaned. Also, when I rubbed it hard, scratches appeared on the rubber surface.

The rubber elastic base material of Comparative Example B has a high surface tackiness.

Continuous and smooth conveyance was not possible. The adhesiveness between the cover film and the rubber surface was also strong, and force was required to peel off the cover film. There were local dents caused by air pockets.

In the rubber elastic base material of Comparative Example 7, the adhesive force or adhesive force between the cover film and the rubber was strong, and when the cover film was peeled off, a part of the rubber was attached to the cover film side, and the rubber surface was destroyed.

In Comparative Example 8, the rubber surface had strong adhesiveness and could not be conveyed continuously and smoothly. In addition, there were two local areas with poor flatness due to air pockets. The image of the first version that was partially created was good.

Example 5 Using the rubber elastic base material of Example 6, a solution with a solid content of 60 weight ratio having the following composition (solvent: methyl ethyl ketone/n-butanol, = 8/2) was coated with the coater shown in Figure 2, and 16
Although a 20μ thick ω layer was formed by treating the substrate at 0'a for 5 minutes, the rubber elastic base material could be transported smoothly and a good surface condition was obtained.

“Nila Ball 1072” 20 parts by weight (NBR manufactured by Zeon) “Super Beckamine L125-60# 80 parts by weight (
Melamine resin manufactured by Dainippon Ink Industries) Further, a photosensitive layer, an adhesive layer and a silicone layer were coated on this coating layer under the same conditions as in Example 6 to form two groups, and a good image was obtained. Ta.

Comparative Example 9 An attempt was made to apply the same coating layer as in Example 5 using the rubber substrate of Comparative Example 8, but the rubber substrate meandered.

Unable to apply continuously.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of essential parts of an apparatus for molding and processing a base material using a thermoplastic elastomer, and FIG. 2 is a schematic diagram of an apparatus for applying a photosensitive agent or the like onto a base material. 1: Molding die 2: Pressure roll: Cooling roll 4: Peeling roll 5; Winding roll 6: Support 7: Elastomer 8: Cover film 9 2 Cover film 10: Base material 11: Unwinding roll 12: Peeling Roll 16: Coating roll 14: Coating liquid supply head 15: Heating furnace 16: Pressing roll 17: EPC 18: Winding roll 19: Cover film 20: Base material 21: Patented film Patent applicant Azuma Shi Co., Ltd.

Claims (1)

[Claims] In a waterless lithographic printing plate precursor using a support having rubber elasticity, the surface of the rubber elastic layer of the support has a center line average roughness Ra of 0.2 to 1.0 μ and a ten point average roughness Rz of 0.5. ~
A waterless lithographic printing plate original plate characterized by having an unevenness of 10μ.・