JPS6260704B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a developer for an electrophotographic offset printing original plate, and more specifically, a developer containing a specific dialkyl sulfosuccinic acid metal salt or an aliphatic amine fatty acid salt and a specific copolymer dispersed in a carrier liquid. The present invention relates to a developer for an electrophotographic offset printing original plate, which is used to create an offset printing original plate obtained by developing or transferring an electrostatic latent image in electrophotography. Conventionally, the liquid developer used to obtain an electrophotographic offset printing original plate is a resin, oil, or fat that has a polarity control and dispersion stabilizing effect on the surface of a pigment or dye that has charge control and color development ability. is adsorbed or coated and dispersed as a toner in a carrier liquid with high electrical insulation and low dielectric constant. Here, resins and oils used include rosin, steverite, linseed oil, alkyd resin, styrene resin, epoxy resin, phenol-modified resin, acrylic resin, synthetic rubber, ethyl cellulose, etc., and pigments used include aniline black, cyanine blue, carbon black, Rhodamine and the like are used. However, toners made from developers using these resins and oils exhibit relatively clear polarity and good dispersibility in the early stages of production, but as time passes, the resins attached to the pigment or dye particles gradually degrade. As the toner is eluted or diffused into the carrier liquid, the polarity of the toner becomes unclear and induces sedimentation and aggregation.As a result, offset printing original plates made using such a developer have problems such as print rise, solid area filling, It has drawbacks such as poor performance in terms of image density and printing durability. On the other hand, pigments used for charge control and color development of images are oil-sensitive, that is, have a low receptivity to ink used in offset printing, compared to resins used in toners. The produced off-mat printing original plate results in printed matter that is unsatisfactory in terms of print start-up, solid areas, and image density. Therefore, in order to overcome the drawbacks of the former toner resin, toners using vinyl compounds grafted onto pigment or dye particles have been proposed, but the grafting rate is low and the developer performance such as dispersion stability and charge control is poor. I haven't found anything that satisfies both of these at the same time. In addition, a developer using a graft copolymer obtained by graft polymerizing a polymerizable monomer to a styrene-butadiene copolymer as a toner resin has been proposed, but the main polymer is styrene.
Because butadiene copolymers are insoluble in aliphatic nonpolar solvents that are normally used as carrier liquids for liquid developers, it is generally necessary to use aromatic solvents such as toluene during polymerization, and the graft copolymers obtained in this way When a toner consisting of a toluene solution and pigment or dye particles is dispersed in an aliphatic solvent to form a liquid developer, dispersibility, transparency, etc. deteriorate due to separation of the graft copolymer and changes in solubility. Therefore, offset printing original plates made using such a developer also have the same defects as described above. Furthermore, in order to eliminate the influence of pigments in the latter toner, toners that do not contain pigments or contain a small amount of pigments are considered. We proposed a liquid developer for electrostatic photography that is dispersed in a liquid (Japanese Patent Application Laid-open No. 19605/1983). This developer has extremely fine resin particles stably dispersed in the carrier liquid, and has excellent reproducibility (resolution) of fine lines and excellent adhesion. It is extremely effective for creating printing master plates. However, in this developer, the resin particles (toner) in the carrier liquid are not necessarily sufficiently charged, and as a result, the speed at which the toner adheres to the electrostatic latent image during development, that is, the development speed, is slow, and a sufficient amount of toner adhesion is not achieved. can't get it. Therefore, when printing is carried out using an offset printing original plate prepared using this developer, the density at the start of printing tends to be insufficient. For these reasons, the present inventors have conducted various studies and examinations based on the electrostatic photographic liquid developer proposed above, and have found that certain dialkyl sulfosuccinate metal salts or By adding the aliphatic amine fatty acid salt, the resin particles come to exhibit clear charge polarity and amount of charge even if they do not contain pigments, and as a result, the offset printing original plate developed with the developer becomes more It was confirmed that extremely satisfactory printed matter could be obtained. The present invention has been completed based on this. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a developer for an electrophotographic offset printing original plate having excellent dispersion stability, fixing properties, transparency, and the like. Another object of the present invention is to provide a developer suitable for producing an electrophotographic offset printing original plate from which high-quality printed matter can be obtained. That is, the present invention is made by dispersing charged particles in a carrier liquid of petroleum-based aliphatic hydrocarbon,
The charged particles have the general formula

[Formula] (R ₁ and R ₂ are alkyl groups having 6 to 12 carbon atoms, Me is a metal ion) or a dialkyl sulfosuccinic acid metal salt represented by the general formula R ₃ COOH ₃ NR ₄ (R ₃ is a carbon number 2 ~6 alkyl group, _R4 represents an alkyl group having 8 to 18 carbon atoms) and a monomer represented by the following general formula (A) in Steps A, B, and C below. and glycidyl (meth)acrylate, or a copolymer of a monomer represented by the following general formula (A) and an unsaturated carboxylic acid or its anhydride; (b) the copolymer is glycidyl (meth)acrylate; When the structural unit is unsaturated carboxylic acid or its anhydride, and when the unsaturated carboxylic acid or its anhydride is the structural unit, glycidyl (meth)acrylate is graft-polymerized; Alternatively, a monomer represented by formula (B) is grafted with a monomer represented by general formula (C) below. General formula (A)

[Formula] R ₅ is -H or -CH ₃ X is -COOCnH _2o+1 , -OCOCnH _2o+1 or -
OCnH _2o+1 (6≦n≦20) is shown. General formula (B)

[Formula] R ₅ is -H or -CH ₃ Y is COOCnH _2o+1 (1≦n≦4), -
OCOCmH _2n+1 (1≦m≦5),

【formula】

[expression] or

[Formula] is shown. General formula (C)

[Formula] R ₅ is -H or -CH ₃ Z is

[Formula] (n, m are integers from 1 to 4), -COOH, -COOC ₂ H ₄ OH,

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

[expression] or

[Formula] is shown. This is a developer for an electrophotographic offset printing original plate, characterized in that it contains a copolymer obtained by. The present invention will be explained in more detail below. The copolymer (graft copolymer) obtained by the above steps A, B, and C can be stably dispersed in a petroleum-based aliphatic hydrocarbon carrier liquid in a cloudy to translucent state. In other words, in this copolymer, the trunk portion is composed of a copolymer that is soluble in the carrier liquid and has a component capable of ester reaction, and the branches branched from the trunk are graft polymer parts that are soluble in the carrier liquid. and a graft polymerization portion that is insoluble in the carrier liquid and has the effect of controlling the charge of the pigment or dye particles. Therefore, this graft copolymer does not dissolve in the carrier liquid or not, but becomes semi-permanently suspended particles in the carrier liquid and stabilizes its dispersion. The trunk portion, which has a polymer chain as an essential component that can be dissolved in a carrier liquid, contains an acrylic ester or methacrylic ester having 5 to 20 carbon atoms such as lauryl methacrylate, 2-ethylhexyl methacrylate, and stearyl methacrylate in the polymer part that is soluble in the carrier liquid. Monomer (represented by the above general formula (A))
is used to introduce unsaturated groups, and unsaturated fatty acid or anhydride monomers such as glycidyl methacrylate or acrylic acid and methacrylic acid, maleic acid, and maleic anhydride are introduced.
The polymerization ratio of the monomer represented by the general formula (A) and the monomer for introducing an unsaturated group in this trunk portion is 0.01 to 0.1 part by weight of the latter monomer to 1 part by weight of the former monomer. It is preferable that there be. If the latter is less than 0.01 part by weight, graft bonding will not occur, and if it is more than 0.1 part by weight, gelation will occur and the desired copolymer will not be obtained. The branch polymer condensed to the trunk portion in the presence of a tertiary amine and a polymerization inhibitor is an unsaturated carboxylic acid or an unsaturated carboxylic acid anhydride when the trunk portion contains glycidyl (meth)acrylate;
When the trunk portion contains an unsaturated carboxylic acid or an unsaturated carboxylic acid anhydride, it is glycidyl (meth)acrylate. Further, the monomer that is insoluble in the carrier liquid and imparts dispersion stability to the toner, which is graft-bonded to this branch portion, is a monomer represented by the general formula (B),
Or a monomer represented by general formula (B) and a monomer represented by general formula (C). The solubility of the graft copolymer thus obtained is controlled to such an extent that it is just dispersed within the carrier solvent itself of the developer, resulting in extremely excellent dispersibility and fixing properties. In the present invention, the dialkyl sulfosuccinic acid metal salt or aliphatic amine fatty acid salt together with the thus obtained graft copolymer constitutes the charged particles, and these additives are sufficient even for toner particles that do not contain pigments. It has a strong charging effect. This dialkyl sulfosuccinic acid metal salt can be easily produced by esterifying maleic anhydride with alcohol and then heating it together with a hydrogen sulfite metal salt under pressure. All metals can be used here, such as calcium, aluminum, cobalt, manganese,
Metal salts such as iron are effective in controlling electric charge. Moreover, among these, manganese salt has stable charging performance over time, and in the case of cobalt salt, toner particles can be made to have an extremely high amount of charge. These additives (dialkyl sulfosuccinic acid metal salts, aliphatic amine fatty acid salts) can change the charging state depending on their type or amount added. For example, when a calcium salt or aluminum salt of dialkyl succinic acid is added, the resin particles exhibit a uniform negative charge, whereas when a manganese salt, cobalt salt, or aliphatic amine fatty acid salt of dialkyl succinic acid is added, the resin particles become negatively charged. The resin particles are uniformly positively charged. Moreover, when the amount of the manganese salt or cobalt salt of dialkyl succinic acid added increases, the polarity tends to be reversed. These charging properties are appropriately selected depending on the charging polarity of the electrophotographic photoreceptor used, the developing method (positive-positive, negative-positive), etc. The amount of the dialkyl sulfosuccinic acid metal salt and aliphatic amine fatty acid salt added is 0.01 to 100 parts by weight, preferably 0.1 parts by weight, per 1 part by weight of the above-mentioned specific graft copolymer.
~10 parts by weight. Thus, by coexisting the dialkyl sulfosuccinic acid metal salt or the aliphatic amine fatty acid salt in the graft copolymer, the charging of the resin particles in the carrier liquid becomes sufficiently satisfactory. In order to actually prepare the developer according to the present invention, the dispersion of the above-mentioned graft copolymer must have an electrical resistance of 10 ⁹ Ω.
The solution may be diluted with a petroleum-based aliphatic hydrocarbon carrier liquid having a dielectric constant of 3 cm or more and a dielectric constant of 3 or more, and the solution of the dialkyl sulfosuccinate metal salt or aliphatic amine fatty acid salt may be added and mixed therein. Of course, a dispersion of a graft copolymer with a dialkyl sulfosuccinic acid metal salt or an aliphatic amine fatty acid salt added and dissolved may be diluted with a carrier liquid. The carrier liquid used here includes, for example, paraffinic or isoparaffinic hydrocarbons (product names manufactured by Etsuso Corporation - Isopar H, Isopar G, Isopar L, Isopar K, Naphtha No. 6, Solbetuso). 100), n-heptane, n-hexane, i-octane, n-octane, etc., and these may be used alone or in combination of two or more. Furthermore, a coloring agent may be mixed into the toner component consisting of this specific graft copolymer and a specific dialkyl sulfosuccinic acid metal salt or aliphatic amine fatty acid salt, but it is used in a very small amount in order to increase the oil sensitivity of the toner particles. It is desirable that As the coloring agent, both pigments and dyes can be used, and any colorant known in this field can be used. Examples of colorants used include carbon black, aniline black, and Pigment Black Extra (manufactured by BASF, West Germany) as black colorants, and Sanyo Final Rose G (manufactured by Sanyo Shiki Co., Ltd.) as red colorants. Arnal Rose Lake (manufactured by Tokyo Ink Co., Ltd.), Rhodamine Y Tona (manufactured by Dainippon Ink Chemical Co., Ltd.), Dainichi First Pink GX (manufactured by Dainichi Seikagaku Co., Ltd.), Ultra Rose 3B (manufactured by Toyo Ink Manufacturing Co., Ltd.), First Pink B Splat (manufactured by BASF, West Germany), First Rose Lake FB (manufactured by Tokyo Ink),
Fast Rose BX (manufactured by Dainichiseika Co., Ltd.), Permanent Yellow HR as a yellow colorant
(manufactured by Ciba, Switzerland), 2600 Benzidine Yellow (manufactured by Dainichiseika), First Benzidine Yellow YB-5708 (manufactured by Harman Color, USA), Benzidine Yellow - 10G (manufactured by Toyo Ink Mfg. Co., Ltd.), Sumirar First Yellow
10GF (manufactured by Dainippon Ink & Chemicals), Benzidine Yellow 940 (manufactured by Kujusha), Sanyo Benzidine Yellow (manufactured by Sanyo Shikisha), Benzidine Yellow GR (manufactured by Sansuisha), Cyanine Blue PRP-B as a blue colorant, Cyanine Blue BN (manufactured by Toyo Ink Manufacturing Co., Ltd.), Sanyocyanine Blue BS (manufactured by Sanyo Shiki Co., Ltd.), Dainichi Cyanine Blue B, Dainichi Cyanine Blue BF (manufactured by Dainichisei Chemical Co., Ltd.),
Sumitomocyanine Blue HBC (manufactured by Sumitomo Chemical), Fastogen Blue B, Fastogen Blue BS (manufactured by Dainippon Ink and Chemicals), Heliogen Blue B (manufactured by BASF, West Germany), Phthalocyanine Blue B (Tokyo Ink) company) etc. When blending these colorants,
It is desirable that the graft copolymer be completely miscible and finely dispersed in the graft copolymer solution. By using the developer of the invention thus produced, extremely clear images can be obtained. In addition,
Conventionally, it has been known to add metal salts, ammonium salts, etc. to electrophotographic developing solutions containing pigment and dye particles to impart charge polarity in the solution, but as in the present invention, development using suspended resin particles has been known. There are no known examples of adding a specific dialkyl sulfosuccinate metal salt or aliphatic amine fatty acid salt to the liquid. The reason why the developing solution of the present invention has good charging polarity of resin particles has not yet been sufficiently investigated, but resin particles (graft copolymers) also have a strong influence on dialkyl sulfosuccinate metal salts or aliphatic amine fatty acid salts. At the same time as it adsorbs and imparts charge polarity, this adsorption strongly entangles with the carrier liquid soluble portion of the resin particles, and until now pigments such as carbon black have been suspended due to adsorption of metal salts. This is thought to be because the pigment particles show a unique adsorption behavior that is stronger than the adsorption in the pigment particles, that is, more than what was thought to be the case when the pigment particles are charged. In order to create an electrophotographic offset printing original plate using this developer, a photoconductive layer consisting of a photoconductive powder such as zinc oxide dispersed in a resin binder is provided on a paper support. A method of forming an electrostatic latent image on photosensitive paper using an electrophotographic method and developing it, or forming an electrostatic latent image on a photoreceptor having a selenium vapor deposited layer using an electrophotographic method and developing it; An electrostatic latent image is formed by transferring it onto a support such as an aluminum plate or plastic film, or by electrostatic printing or electrostatic recording on a recording material having a dielectric layer, and then developed. Any method such as transfer may be used. Next, examples will be shown. Example 1 194 g of lauryl methacrylate and 6 g of glycidyl methacrylate were copolymerized in Isopar H, and 0.1 g of triethylamine and 1.5 g of methacrylic acid were added thereto and reacted at 80°C for 20 hours. After that, 150 g of vinyl acetate and azobisisobutyl were copolymerized. When 7 g of nitrile was added and polymerized, a stable dispersed polymer was obtained. This dispersion was diluted with Isopar H until the solid content became 5% by weight, and 200 ml of a 5% by weight solution of manganese di(dodecyl)sulfosuccinate in cyclohexane was added thereto and mixed well to prepare a developer. . Using this developer, a copy image is formed on an electronic recopy master NR (trade name) using a commercially available electrophotographic copying machine (manufactured by Ricoh Co., Ltd., trade name BS-470), used as a printing original plate, and after etching is printed using an offset printing machine. As a result, the printing start-up was quick (image density 1.2 on the 2nd page), the bright lines were clear, and the solid areas were filled in well, resulting in a good print (image density 1.3 on the 50th page).
was obtained, and the image quality remained unchanged even after printing 3000 sheets. Example 2 A printing original plate obtained using a developer prepared in the same manner as in Example 1 except that styrene was used instead of vinyl acetate also exhibited printing characteristics similar to those in Example 1. Example 3 The graft copolymer solution prepared using tridecyl methacrylate in place of lauryl methacrylate in Example 1 was diluted with Isopar H to a solid content of 5% by weight, and 5% by weight of dodecylammonium butyrate in cyclohexane was diluted with Isopar H. 300 ml of the solution was added and mixed well to prepare a developer. A printing original plate was prepared using this developer in the same manner as in Example 1, and offset printing was performed after etching. The printing start-up was quick and reproduction of fine lines and solid areas was also good. Example 4 The graft copolymer solution prepared in Example 1 using methyl methacrylate instead of vinyl acetate was diluted with Isopal H to a solid content of 5% by weight, and 5% by weight of calcium di(stearyl)sulfosuccinate was added to this solution. % cyclohexane solution
A developing solution was prepared by adding 300 ml and mixing well. A printing original plate was prepared by transferring the toner image developed with this developer and a commercially available electrophotographic copying machine (manufactured by Ricoh Co., Ltd., trade name DT-1200) onto a direct-drawing offset master. When this original plate was used for printing in the same manner as in Example 1, prints were obtained that had a quick start-up (image density on the second sheet was 1.1) and clearly reproduced fine lines, and 3,000 sheets were printed. There was no change in image quality.

Claims (1)

[Scope of Claims] 1. Charged particles are dispersed in a carrier liquid of petroleum-based aliphatic hydrocarbon, and the charged particles have the general formula [Formula] (where R ₁ and R ₂ are carbon numbers (6 to 12 alkyl groups, Me indicates a metal ion) or a dialkyl sulfosuccinic acid metal salt represented by the general formula R ₃ COOH ₃ NR ₄ (wherein R ₃ has 2 to 6 carbon atoms)
an alkyl group, R ₄ represents an alkyl group having 8 to 18 carbon atoms);
A developer for an electrophotographic offset printing plate, characterized by containing the following copolymer. (Copolymer) (a) A copolymer of a monomer represented by the following general formula (A) and glycidyl (meth)acrylate, or a copolymer of a monomer represented by the following general formula (A) and an unsaturated carboxylic acid or its anhydride. (b) When the copolymer has glycidyl (meth)acrylate as a constituent unit, unsaturated carboxylic acid or its anhydride, and when the copolymer has unsaturated carboxylic acid or its anhydride as a constituent unit, glycidyl (meth)acrylate. and (c) further grafting a monomer represented by the following general formula (B) or a monomer represented by the general formula (B) and a monomer represented by the following general formula (C) to the graft branch part. The resulting copolymer. General formula (A) [Formula] R ₅ is -H or -CH ₃ X is -COOCnH _2o+1 , -OCOCnH _2o+1 or -
OCnH _2o+1 (6≦n≦20) is shown. General formula (B) [Formula] R ₅ is -H or -CH ₃ Y is -COOCnH _2o+1 (1≦n≦4), -
OCOCmH _2n+1 (1≦m≦5), [Formula] Indicates [Formula] or [Formula]. General formula (C) [Formula] R ₅ is -H or -CH ₃ Z is [Formula] (n, m are integers from 1 to 4), -COOH, -COOC ₂ H ₄ OH,
[Formula] [Formula] [Formula] [Formula] [Formula] [Formula] [Formula] [Formula] Indicates [Formula] [Formula] or [Formula].