JPH0221580B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is an original plate for creating a lithographic plate that enables printing without using dampening water, and it forms an image layer (hereinafter referred to as a toner image) by an electrophotographic process. Specifically, the present invention relates to a printing original plate for easily making a lithographic plate. When performing lithographic printing, there is a lithographic printing plate known as a dry offset plate that utilizes the excellent ink repellency of silicone, which allows printing without using dampening water. , a plate-making method has been proposed in which an ink-receptive area is provided on a silicone resin using an electrophotographic method. For example, in Japanese Patent Application Laid-open No. 50-904,
Printing plate with toner particle images embedded in ink-repellent silicone resin, JP-A-49
Publication No. 119904 discloses a printing plate, etc., in which a toner image is transferred to a layer made of silicone rubber and inorganic powder, and then thermally fixed. However, in these lithographic printing plates, although the silicone resin used has good toner adhesion when uncured, after curing, the ink repellency is good due to its low surface energy. A phenomenon of repelling of the melted toner image is observed, resulting in thin lines, cuts, and a pattern of spots on the solid surface. Moreover, since sufficient adhesion between the toner image and the silicone resin cannot be obtained, it is not possible to obtain a large number of clear and excellent printed materials. For this reason, in order to improve the adhesion and wetting characteristics between the toner image and the silicone resin,
Publication No. 50-71406, No. 50-78403, No. 50-
Publication No. 78404 discloses a method of applying semi-cured or uncured silicone resin, transferring and thermally fixing a toner image, and then curing the silicone resin. Also, JP-A-52-29305, JP-A-52-29305,
Publication No. 161306 describes a method of introducing a polar group that is compatible with or reactive with toner into a silicone resin;
No. 51-84302 discloses a method of applying a silicone resin in which an ink-repellent portion and a toner-receptive portion are graft-polymerized. However, it is difficult to store silicone resin in a semi-cured or uncured state for a long period of time, and silicone resins that are blended or graft-polymerized with toner-receptive substances have good toner adhesion. Even when printing, background smear tends to occur in printing. An object of the present invention is to provide a lithographic original plate that does not require dampening water and does not have the above-mentioned drawbacks. Another object of the present invention is to provide a lithographic original plate that can be easily made by applying an electrophotographic method. The present inventors have been conducting research for many years on methods for improving toner fixing properties, wetting characteristics of fused toner images, and surface smoothness without impairing the ink repellency of silicone resin. It has been found that the fixability of toner images can be improved by mixing a specific fluorine-containing surfactant compound into a silicone resin. Furthermore, between the silicone resin layer containing the fluorine-containing surfactant compound and the support,
A resin that is highly compatible with the toner resin, or if the toner resin used has a reactive active group, a resin that has a specific chemically active group that can chemically bond with the toner. It was confirmed that the fixing properties, wetting characteristics, and surface smoothness of the toner can be further improved by providing an anchor coat layer, and the present invention has been completed. That is, in the present invention, an anchor coat layer made of a resin having a reactive active group that is compatible with the toner image during thermal melting or capable of chemically reacting with the toner is provided on the support, and the anchor coat layer is formed on the anchor coat layer. is provided with an ink repellent layer made of a silicone resin containing a fluorine-containing surfactant compound represented by the following general formula (): Rf-SO ₂ -Y, preferably a room-temperature or low-temperature curing silicone resin, The present invention is a lithographic original plate that does not require dampening water, and is characterized in that an alignment layer of a fluorine-containing surfactant compound is formed on the ink repellent layer. However, in the general formula (), Rf represents a fluorinated aliphatic group having 3 to 12 carbon atoms, and Y represents a hydrophilic group having a nitrogen-containing linking moiety. Hereinafter, the above-mentioned present invention will be explained in detail based on the drawings. FIG. 1 is an enlarged partial sectional view schematically illustrating the structure of the lithographic original plate of the present invention. In the original plate, an anchor coat layer 2 is formed between a support 1 and an ink repellent layer 3, and the anchor coat layer 2 is an image layer, that is, a toner image 5, which is formed over the original plate during plate making. or a resin having an active group that is reactive with the toner image 5. The ink repellent layer 3 is a silicone resin layer in which a fluorine-containing surfactant compound 3' represented by the general formula () is dispersed or dissolved. A surface alignment layer 4 of a fluorine-type surfactant compound is produced. Next, FIG. 2 shows a state in which an arbitrary image layer such as characters, figures, symbols, and patterns made on an electrophotographic photoreceptor or a transfer base material 6, that is, a toner image 5, is placed directly on the original plate. FIG. 3 shows the toner image transferred onto the original plate by electrostatic transfer or pressure transfer. Furthermore, FIG. 4 shows the state after the toner image of the original plate is heated and melted, and the surface alignment layer 4 evaporates during heating.
This is the structure of the printable version. However, the planographic plate obtained in this way sometimes has a surface alignment layer 4 in the non-image area even after the toner image 5 is heated.
may remain slightly. FIG. 5 shows such a state. In that case, the surface alignment layer 4 can be removed very easily by wiping the surface of the obtained plate with methanol or other polar solvent. It is possible. In this way, a printable lithographic plate as shown in FIG. 4 is obtained. As described above, the lithographic original plate of the present invention comprises a support 1, an anchor coat layer 2, an ink-repellent silicone resin layer 3 containing a fluorine-containing surfactant compound 3', and a fluorine-containing surfactant compound 3'. It is composed of a surface alignment layer 4. The support 1 may be of any type, but since it is used as a lithographic printing plate, it is preferably one with high strength. The role of the anchor coat layer 2 is to firmly adhere the toner image 5 onto the silicone resin surface and to improve the wettability of the silicone resin surface.For this purpose, the resin used for the anchor coat layer 2 is It is necessary to use a resin that is compatible with the toner image 5 during heating, or a resin that has an active group that can chemically react with the toner image 5. usually,
Examples of resins used as toners include epoxy resins, saturated and unsaturated polyester resins, polyamide resins, styrene-butadiene resins, phenolic resins, styrene-acrylic resins,
Styrene-maleic anhydride resin, xylene resin,
These include vinyl chloride-vinyl acetate copolymer and silicone resin, and these resins may be used alone or as a mixture. The anchor coat resin must be a combination of a resin that is compatible with these toner resins when heated, or a resin that has a reactive active group that can form a chemical bond when the toner is thermally melted. is desirable. Such reactive active groups include amino groups, epoxy groups, unsaturated groups, hydroxyl groups, carboxyl groups,
Examples include mercapto groups, isocyanate groups (including blocked ones), nitrile groups, imino groups, etc. Resins with the above active groups include epoxy resins, polyamide resins, urea resins, phenolic resins, styrene-maleic anhydride. Copolymer resins, polyester resins, acrylic and methacrylic resins,
Examples include styrene-butadiene resin, polysulfide resin, blocked isocyanate resin, and mixtures thereof. Table 1 lists examples of such combinations of anchor coat resins and suitable toner resins that are reactive or compatible.

【table】

[Table] To provide the anchor coat layer 2, the above resin alone or a mixture of two or more of them is mixed with an appropriate solvent, and this is coated on the support 1 with a doctor blade, air knife coating, Alternatively, it can be applied using wire knife coating or the like. The coating amount needs to be an appropriate thickness so that the toner image is sufficiently anchored to the silicone resin surface, and it is desirable that the coating has a dry thickness of at least 0.1 μm. Furthermore, the anchor coat layer 2 may be slightly cross-linked and cured by combining resins having appropriate active groups or adding a photosensitive resin to prevent it from being attacked by the solvent of the silicone resin solution to be applied next. It is possible. The silicone resin forming the ink repellent layer 3 provided on the anchor coat layer 2 may be one having only methyl-containing groups in the polymer chain, such as polydimethylsiloxane, or one having methyl- and phenyl-containing groups in the polymer chain. Rubbers that have both methyl groups and vinyl groups, both methyl and fluorine groups, or methyl, phenyl, and vinyl groups in the polymer chain can be mentioned. Room temperature curing silicone resins are preferred, particularly silicone rubbers for release paper used in pressure-sensitive adhesive sheets (e.g. YSR-3022, YSR-7031, manufactured by Toshiba Silicone Co., Ltd.).
Shin-Etsu Silicone KS 705F, KS-770, KS-
709 etc.) is optimal. In order to provide the ink repellent layer 3 and the surface alignment layer 4 of a fluorine-containing surfactant compound, a silicone curing catalyst such as an organic tin compound, an organic zinc compound, an organic titanium compound, or an organic amine is added to the silicone resin. Further, a solution of the fluorine-containing surfactant compound represented by the general formula () in a polar solvent is mixed and stirred, and if necessary, a suitable solvent that does not attack the anchor coat layer, such as a hydrocarbon solvent such as hexane or n-heptane, is added. Add and mix, apply with a doctor blade, wire coater, etc., and dry and harden at room temperature or low temperature. During solvent evaporation, the fluorine-containing surfactant compound 3' dispersed or dissolved in the silicone resin solution has a high surface activity, so a part of the surface active compound is oriented on the silicone resin surface. A surface alignment layer 4 is formed. Further, the remaining fluorine-containing surface active compound is dissolved or dispersed in the silicone resin, and can serve as a path for the toner to permeate and diffuse during heating. The surface-active compound of the general formula () added to the silicone resin has Rf in the formula of 3 to 3 carbon atoms.
12 perfluoroalkyl groups are preferred. Depending on the polar group of Y, such compounds include those with nonionic groups, those with anionic groups, those with cationic groups,
It is divided into bisexuals depending on the combination of
Examples include the following. (however,
In the formula, R is H or a _C1 to _C12 aliphatic group, and R' is
Represents a _C1 - _C3 aliphatic group. ) The amount of such fluorine-containing surfactant compound to be added is 0.1 to 10% of that of silicone resin.
The amount by weight is appropriate, and about 0.2 to 4 weight % is particularly preferable. The coating amount of the ink repellent layer 3 varies depending on the state of penetration and diffusion of the toner layer 5 and the anchor coat layer 2, as will be described later, but is suitably between 0.1 and 50 microns. In particular, it is preferably about 1 to 15 .mu.m. If it is less than 0.1 .mu.m, the anchor coat layer will penetrate to the surface of the silicone resin, which tends to cause background smearing. If it is more than 50 .mu.m, the toner image will have poor fixability. Electrophotographic engraving methods that can be applied to the printing original plate of the present invention include a xerography method in which a toner image is transferred to a silicone coated surface, or a method in which an electrostatic latent image on an electrophotographic photoreceptor is transferred onto an ink-repellent layer. Another example is a latent image transfer method in which a toner image is formed by developing with liquid or powder toner. In the toner image 5 provided by the above electrophotographic process, Table 1
A resin in a suitable combination with the anchor coat layer resin should be used, such as those shown in . The toner image 5 and the anchor coat layer 2 are
As shown in the figure, the fluorine-containing surfactant compound penetrates and diffuses into the silicone resin during heating and melting. One of the useful effects of fluorine-containing surfactant compounds on this mechanism is their strong ability to lower surface tension. When the toner is thermally melted, a part of the surface alignment layer of the fluorine-containing surfactant compound dissolves into the melted toner.
Reduces the surface tension of fused toner. For this reason,
The molten toner component penetrates and diffuses into the network of the cured silicone resin or into the fluorine-containing surfactant compound dispersed or dissolved in the cured silicone resin. At the same time, like the fused toner, the anchor coat component also penetrates and diffuses into the silicone resin due to the action of the fluorine-containing surfactant compound dispersed or dissolved in the cured silicone resin.
Due to contact with the permeated toner components and crosslinking reaction, the toner image 5 is firmly fixed to the silicone resin surface and does not easily fall off. Furthermore, the surface tension of the melted toner image is reduced due to the dissolution of the fluorine-containing surfactant, and due to the presence of the permeated anchor coat layer,
It has excellent wetting properties for silicone resin and surface smoothness, and is capable of producing very clear printed matter without line thinning, cuts, or solid surface speckles. In addition, by providing an anchor coat layer, the silicone rubber is strongly adhered to the support,
Since the silicone resin has improved abrasion resistance and the toner has high adhesion, the number of sheets printed can be greatly improved. In order to more effectively achieve such a penetration effect, it is also possible to intentionally add a low molecular weight resin component to the toner layer and anchor coat layer. The second usefulness of the fluorine-containing surface-active compound is that it has thermal decomposition, volatility, or sublimation property near the toner melting temperature, and good solubility in polar solvents. That is, the fluorine-containing surfactant compound decomposes when heated to a temperature in the range of 80 to 200°C, depending on its chemical structure, or
Alternatively, it has the property of volatilizing or sublimating in the range of 90 to 200°C. Therefore, at the temperature at which the toner image, which is the ink receiving area, melts, the surface alignment layer 4 of the fluorine-containing surfactant compound on the surface of the silicone resin melts while the toner components penetrate and fix into the cured silicone resin. As it dissolves in the toner, it gradually evaporates through decomposition, volatilization, or sublimation, exposing the silicone resin surface, which becomes an ink-repellent portion. In addition, the fluorine-containing surfactant compound has excellent solubility in polar solvents such as water and alcohol ketones, and dissolves the original plate in water, silicone resins such as methanol, and toner images after fixing the toner. The surface alignment layer 4 of the fluorine-containing surfactant compound is easily removed by wiping with a cloth impregnated with a non-polar solvent, and the silicone resin surface is exposed and becomes an ink-repellent portion. In the original plate, if the surface alignment layer 4 of the fluorine-containing surfactant compound is not removed, the ink repellency is poor, but by removing the surface alignment layer, the ink repellency becomes good and the plate is in a printable state. It is what it is. The toner image is melted and the fluorine-containing surfactant is thermally evaporated by a heat fixing method conventionally used in copying machines, such as heating in a thermal oven or heating with an infrared heater.
It is quite possible. The above mechanism can only be achieved by adding a fluorine-containing surfactant compound to the silicone resin and by providing an anchor coat layer between the ink repellent layer and the support. The features of the invention reside in these points. As described above, the printing original plate of the present invention can be easily plate-made, can express clear lines on a printing medium, has printing durability, and can be printed on a large number of sheets. In addition, since no dampening water is used, there are no problems caused by dampening water, such as emulsification of ink.
Furthermore, the printing machine can also have a simple structure. Next, examples will be explained in more detail.
The present invention is not limited to these. Example 1 For anchor coating consisting of Lacucamide 394-N (trade name, manufactured by Dainippon Ink Chemical Co., Ltd., polyamide resin) 20 parts * Butanol 40 parts A resin solution (non-volatile content concentration 20%**) was applied onto polyethylene laminate paper so that the dry film thickness was 5 μm, and dried at room temperature to form an anchor coat layer. (**represents weight%, the same applies hereinafter) In addition, YSR-3022 (trade name, Toshiba Silicone product,
Silicone resin for release paper) 10 parts YC-6831 (same as above, curing catalyst for YSR-3022)
C ₈ F ₁₇ SO ₂ N was added as an additive (surface-active compound) to 60 parts of a silicone resin solution consisting of 0.4 parts YC-6919 (same as above) and 49.4 parts n-heptane.
(CH ₂ CH ₂ OH) ₂ in 5% methyl ethyl ketone solution
Mix and stir 2.4 parts to prepare a coating solution. This solution was applied onto the anchor coat layer until the dry film thickness was 5 μm.
Apply and cure at room temperature for 24 hours. A toner image was formed on the printing original plate obtained in this way using a dry type electronic copying machine (U-Bix1500 manufactured by Konishiroku Photo Industry Co., Ltd.) using a toner whose main component was an epoxy resin. A lithographic printing plate was prepared by heat treatment for 1 minute. This plate was printed on a small offset printing machine (Model A.B. DICK326, A.
B・DICK), and using dry color process ink N (Dainippon Ink & Chemicals),
When printing was performed without using dampening water, more than 5,000 high-quality prints were obtained. Moreover, this printing original plate showed no change in its performance even after 6 months, and plate making was possible in the same manner. Example 2 In Example 1, the resin solution for anchor coating was a resin solution consisting of 33 parts of Burnok D-750 (trade name, manufactured by Dainippon Ink & Chemicals, blocked isocyanate resin) and 67 parts of ethyl acetate (nonvolatile content concentration 20). A printing original plate was prepared in exactly the same manner except that %) was used, and plate making and printing were performed. As with Example 1, the results of using this original plate showed excellent toner adhesion and ink repellency, and sufficient printing durability of 5,000 sheets or more. Example 3 In Example 1, the anchor coating resins were: Betsukasite P-720 (natural resin-modified maleic acid resin, manufactured by Dainippon Ink & Chemicals) 20 parts Isopropyl alcohol 40 parts Xylol 40 parts (non-volatile content concentration 20%) A printing original plate was prepared in the same manner as in Example 1, except that the resin solution was used, and plate making and printing were performed. As in Example 1, a plate with good ink repellency in the non-printing area and a printing durability of 4000 sheets or more was obtained. Example 4 As a resin solution for anchor coating, Epikote 828 (trade name, liquid epoxy resin, manufactured by Shell Chemical Co., Ltd.), 3 parts Epikote 1001 (same as above, solid epoxy resin, manufactured by Shell Chemical Co., Ltd.), 3 parts Thiokol LP-3 (same as above, polysulfide) 14 parts Toluene 80 parts Epoxy group/sulfide group = 1/2.7 (equivalent ratio) Non-volatile content concentration 20% Using a resin solution, a dry film thickness of 5μ or more is obtained on art paper. A partially crosslinked anchor coat layer was formed by applying the same coating and heating at 140°C for 3 minutes. Furthermore, as an ink repellent layer, YSR-7031 (product name, Toshiba Silicone Co., Ltd. product,
Silicone resin for release paper) 10 parts YC-8610 (same as above, curing catalyst for YSR-7031)
Additives (as surface-active compounds) to 60 parts of a silicone resin solution consisting of 0.3 parts n-heptane and 49.7 parts Mix 2.4 parts of a 5% methyl ethyl ketone solution of
This solution is applied onto the aforementioned polysulfide-epoxy mixed anchor coat layer so that the dry film thickness is 5 μm, and is dried and cured at room temperature for 24 hours.
A toner image mainly made of epoxy resin was applied to the printing original plate obtained in this way in the same manner as in Example 1, and the plate was made by fixing it with an infrared heat fixer at 150°C for 60 seconds. When we conducted a printing test in the same manner as in 1, we found that it has a printing durability of over 5000 sheets.
Moreover, clear printed matter with no ink stains was obtained. Example 5 Anchor coat resin solution (non-volatile content
20%) on polyethylene laminate paper to a dry film thickness of 5μ and dry at room temperature. Furthermore, as an additive (surface-active compound) to 60 parts of a silicone resin solution consisting of 10 parts of YSR-3022 (mentioned above), 0.4 parts of YC-6831 (same as above), 0.2 parts of YC-6919 (same as above) and 49.4 parts of n-heptane.

Mix and stir 1.2 parts of a 5% butyl cellosolve solution of [Formula] to obtain a coating solution. This solution was applied onto the epoxy resin anchor coat layer described above so as to have a dry film thickness of 5 μm, and was dried and cured at room temperature for 24 hours. A toner mainly composed of polyamide resin and a toner mainly composed of styrene-maleic anhydride resin were applied to the printing original plate obtained in this way using a xerographic electronic copying machine (U-Bix 101, manufactured by Konishi Roku Photo Industries Co., Ltd.). A transferred image was created using the toner and fixed by heating at 160°C for 1 minute to create a lithographic printing plate. When printing was carried out using this plate in the same manner as in Example 1, clear images with no broken lines and good reproducibility in the halftone image area were obtained. However, the toner image on the plate had not fallen off. Example 6 In Example 1, as an additive
_2.4 % butyl cellosolve solution _at 2.5% _{in C8F17SO2NH2}
The original plate was obtained in exactly the same manner except that the original plate was used. As a result of using this original plate, the same good results as in Example 1 were obtained. Example 7 In Example 5, as a surface active compound

An original plate was obtained in exactly the same manner except that 2.4 parts of a 5% butyl carbitol solution of the formula was used, and then plate making was performed. After wiping this plate evenly with gauze soaked in methanol and drying it with air, it was attached to a lithographic printing machine.
When printed in the same manner as in Example 5, a clear printed matter with excellent ink repellency in the non-image area was obtained. Furthermore, no changes such as falling off were observed in the toner image on this printing plate even after printing 6000 sheets. Comparative Example 1 Same as Example 1 except that the anchor coat layer was not provided, no additives were used, and only the silicone resin solution was used, but an ink repellent layer was provided, and the same as Example 1 With the plate on which the original plate was obtained and the toner image was subsequently formed, there was almost no background smearing on the printed matter, but the printing durability was completely poor. Comparative Example 2 A silicone resin solution was applied in exactly the same manner as in Example 1, except that only a silicone resin solution containing a surface-active compound was used without providing an anchor coat layer. After being stored at room temperature for 24 hours, the plate on which a toner image was formed using the same plate-making method as in Example 1 had almost no scuffing on the printed matter, but the toner image on the plate surface had slight line breaks. Furthermore, a repelling phenomenon due to silicone appeared on the solid surface. Also, this version is 2000
After printing, a portion of the solid surface had fallen off.

[Brief explanation of drawings]

The drawings schematically show embodiments of the present invention, and FIG. 1 is an enlarged partial cross-sectional view of a planographic original plate according to the present invention, and FIGS. It is an enlarged partial cross-sectional view schematically showing a process of plate making using an electrophotographic method using an original plate,
The symbols in the figure are as follows. 1...Support, 2...Anchor coat layer, 3...
...Ink repellent layer, 3'...Surface active compound particles,
4... Surface-active compound alignment layer, 5... Image layer (toner image), 6... Substrate for electrophotographic image transfer.

Claims (1)

[Scope of Claims] 1 In a lithographic original plate in which an ink repellent layer is formed on a support, an anchor coat layer 2 is formed between the support 1 and the ink repellent layer 3, and the anchor coat layer 2 is The ink repellent layer is formed of a resin that is compatible with the toner image layer 5 that is sometimes heat-fixed and superimposed on the ink repellent layer 3, or a resin that has an active group that is reactive with the image layer 5. Layer 3 has the general formula: Rf- _SO2 -Y (wherein Rf represents a fluorinated aliphatic group having 3 to 12 carbon atoms, and Y represents a hydrophilic group having a nitrogen-containing linkage). The ink repellent layer 3 is formed of a silicone resin mixed with the fluorine-containing surface active compound shown below.
An original plate for a lithographic plate that does not require dampening water, characterized in that an orientation layer 4 of a fluorine-containing surfactant compound is formed thereon. 2. The original plate according to claim 1, wherein the fluorine-containing surfactant compound has a perfluoroalkyl group as the fluorinated aliphatic group. 3. The original plate according to claim 1 or 2, in which the fluorine-containing surface-active compound is mixed in an amount of 0.1 to 10% by weight of the silicone resin. 4 The resin forming the anchor coat layer 2 contains an amino group, an epoxy group, an unsaturated group, a hydroxyl group, a carboxyl group, an aldehyde group, a mercapto group, an isocyanate group (blocked) as an active group having reactivity with the image layer 5. The original plate according to Claims 1, 2, or 3, which is a resin having at least one of the following: a nitrile group, and an imino group. 5. The original plate according to claim 1, 2, 3 or 4, wherein the anchor coat layer 2 has a thickness of 0.1μ or more, and the ink repellent layer 3 has a thickness of 0.1 to 50μ.