JP2699483B2 - Desensitizing ink for lithographic printing without water - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a desensitizing ink for waterless lithographic printing which is preferably used when performing waterless lithographic printing on pressure-sensitive copying paper or the like.

[Prior Art] Printing of desensitizing ink for pressure-sensitive copying paper is currently performed by letterpress printing, intaglio printing, lithographic printing, and stencil printing. However, the breakdown is that the letterpress printing method and the intaglio printing method, which were conventionally mainstream, are now shifting to the lithographic printing method. The reasons for this are that plate making is easier in lithographic printing than in relief printing, etc., that dimensional accuracy is high,
Further, the low printing pressure does not break the coloring microcapsules applied to the back surface of the pressure-sensitive copying paper, and the printing quality is excellent. However, pigments and desensitizers contained in desensitizing inks have a high affinity for dampening water for wet lithographic printing due to the high content of hydrophilic substances. As a result, the ink is emulsified with dampening water during printing, and Smearing occurs and printing becomes difficult. Although desensitizing inks have been improved to eliminate such problems, they have not been obtained yet.

On the other hand, lithographic printing without water using fountain solution is conceivable as a method for solving such problems, but a desensitizing ink for lithographic printing without water has not been developed yet. Here the conventional
If the PS desensitizing ink is used for waterless lithographic printing as it is, there will be no ink repellency with the non-image area of the plate surface, so it will not be possible to print due to problems such as background stains and roll-up of paper. .

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned drawbacks of the prior art, and has as its object to provide a highly practical water having good ground stain resistance and excellent printability. None. To obtain a desensitizing ink for lithographic printing.

[Means for Solving the Problems] An object of the present invention is to provide a desensitizer for waterless lithographic printing mainly comprising a desensitizer, a filler and a vehicle reacted with a polyamidoamine and having a viscosity of 500 poise or more. Achieved by ink.

That is, the desensitizing ink for lithographic printing without water of the present invention mainly comprises a vehicle comprising a resin, an oil and a solvent, and a desensitizer and a filler generally used in conventional desensitizing inks.

The desensitizer referred to herein includes, for example, a cationic quaternary ammonium salt (such as dodecyltrimethylammonium chloride) as described in JP-B-33-3921,
Tertiary amines having two polyethylene oxide groups (such as N, N-di-polyoxyethyleneethylamine) as described in JP-A-46-29546 and polyoxyethylene monoamines as described in JP-B-47-38201. Examples thereof include alkyl esters (eg, polyoxyethylene oleyl ester) and polyethylene glycol alkyl phenyl ether (eg, polyethylene glycol nonyl phenyl ether) described in JP-B-49-8288.

Alternatively, the repellency of the ink with a waterless lithographic plate can be improved by esterifying the terminal -OH of the desensitizer with a higher fatty acid.

The resin used as a vehicle component in the present invention includes an oil-soluble phenol resin and a modified phenol resin modified with these polycarboxylic acids or anhydrides thereof, a ketone resin, a polyamide resin, a maleic acid resin,
Examples include, but are not limited to, alkyd resins.

As the oil component used in the present invention, linseed oil, cottonseed oil, tung oil, soybean oil, safflower oil, castor oil,
Examples of the oil component include a dry oil or a semi-dry oil such as tall oil and a fatty acid thereof, and a polymerized oil such as a dimer or tetramer of linseed oil.

The solvent used in the present invention has a boiling point of 200
Petroleum solvents up to 350 ° C are common, such as “Dialen”
168 (manufactured by Mitsubishi Yuka Co., Ltd.), "No. 3 Solver", "No. 4 Solver", "No. 5 Solver", and "No. 0 Solver" (all manufactured by Nippon Oil Co., Ltd.). There is no limitation, and a solvent for ink can be used.

Examples of the filler include white pigments such as titanium oxide and extenders such as zinc sulfide, barium sulfate, magnesium carbonate, calcium carbonate, barium carbonate, magnesium hydroxide, silica and talc. One or more of these fillers may be used. Is used. When these fillers are used, various lipophilic treatments can be performed for the purpose of improving the ink repellency with a waterless lithographic plate.

In the method for preparing an ink of the present invention, a predetermined amount of a resin, an oil, and a solvent are mixed, dissolved by applying heat, and stirred until uniform to obtain a vehicle. Next, a predetermined amount of a desensitizing agent and a filler are added thereto to obtain a desensitized ink. When the resin and the solvent are heated and mixed, an organic aluminum compound, an amine such as polyamideamine, an acid anhydride, an isocyanate, or the like may be added. Further, a reactive silicone oil or a non-reactive silicone oil may be added, or a surfactant may be added. In addition, a wax, a dry preparation and the like can be added.

The proportion of each of these components is not particularly limited, but from the viewpoint of improving the soil resistance and printability, the desensitizers 20 to 20 are used.
60% by weight, vehicle 20-80% by weight, filler 10-40% by weight
It is good to use in the range.

In addition, a preferable ratio of each component in the vehicle is a resin.
It is preferable to use 10 to 40% by weight, 5 to 20% by weight of oil and 5 to 20% by weight of solvent.

In the desensitizing ink for lithographic printing without water of the present invention, the viscosity of the ink obtained by kneading these components must be 500 poise or more (30 ° C.). The viscosity referred to here is E
It was measured with a mold viscometer.

More preferably, the viscosity of the ink is 500 to 4000 poise. If the viscosity is less than 500 poise, the ink will have low ground stain resistance and cannot be used for waterless lithographic printing. On the other hand, when the viscosity of the ink is extremely high, the ink is slightly difficult to use in terms of paper suitability, because the paper is wrapped around the blanket cylinder during printing, although the ground stain resistance is good. However, even such an ink can be used by adding a reducer for dilution or a tack-cutting agent.

[Examples] Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

The stain resistance, paper suitability, and desensitization characteristics in the examples were evaluated by the following methods.

Printing was performed using a waterless planographic printing press VS1000 (manufactured by Toray Engineering Co., Ltd.) at a place where the room temperature was controlled at 20 ° C. The paper used was carbon-free C paper (having a surface coated with a color developer).

Add 0.5% of alkaline blue toner (T-400, manufactured by Morimura Burnish) to the desensitizing ink to be evaluated and 1000
Copies were printed. In the meantime, it was visually checked whether or not a background stain due to ink repulsion failure occurred in the non-image portion, and this was evaluated as the background stain resistance. During this printing, it was checked whether or not a trouble occurred in which the printing paper was wrapped around the blanket cylinder (a solid image with a pattern area ratio of 30%), and this was regarded as paper suitability. Further, the desensitizing property is B
The paper was printed with a layered typewriter, and the color development was checked.

Example 1 40% by weight of a rosin-modified phenolic resin (Tespol SPR130, manufactured by Tokushima Essential Oil Co., Ltd.) and a petroleum-based solvent ("DIALEN" 1
68, manufactured by Mitsubishi Petroleum Corporation) 30% by weight and linseed oil 20% by weight are heated and dissolved in a separa flask. 240 in oil bath
Stir at 30 ° C for 30 minutes to form a homogeneous solution. Next, the temperature of this solution was lowered to 150 ° C., 1% by weight of polyamidoamine (“Versamide” 125, manufactured by Henkel Hakusui) was added, and the mixture was stirred for 30 minutes and then 4 mol of polypropylene glycol ethylene oxide was added thereto. A varnish is obtained by adding 49% by weight of 1/6 oleic esterified product of terminal OH group of the product and stirring and mixing at 80 ° C. for 30 minutes. Next, the obtained varnish is 70% by weight.
Take 20% by weight of titanium oxide and calcium carbonate
10% by weight was added and kneaded well with a three-roll mill to prepare Ink-1 (viscosity of 1250 poise). The ink was evaluated for background stain resistance, paper suitability, and desensitization characteristics, and the results are shown in Table 1.

Example 2 A varnish was prepared in exactly the same manner as in Example 1, except that 0.5% by weight of "Versamide" 140 was added instead of "Versamide" 125. 70% by weight of this varnish
To this, 20% by weight of titanium oxide and 10% by weight of calcium carbonate were added and kneaded well with a three-roll mill to form an ink-2.
(Viscosity set 750 poise). This ink was similarly evaluated for background stain resistance, paper suitability, and desensitization characteristics, and the results are shown in Table 1.

Comparative Example 1 A varnish was prepared in the same manner as in Example 1, except that no polyamidoamine was added when preparing the vehicle.
An ink obtained by using this varnish to form an ink in the same manner as in Example 1 was designated as Ink-3 (viscosity: 120 poise), and the same evaluation was performed.

The mark “○” indicates a commercially usable state, and the mark “X” indicates that it cannot be used commercially.

As shown in Table 1, it can be seen that Inks-1 and 2 are excellent as desensitizing inks in waterless lithographic printing. On the other hand, Ink-3 which does not satisfy the present invention has poor ground stain resistance and can be said to be unsuitable as a desensitizing ink in waterless lithographic printing.

[Effects of the Invention] Since the present invention is configured as described above, it is possible to obtain a highly practical desensitizing ink for waterless lithographic printing which has good ground stain resistance and excellent printability. is there.

Claims (1)

(57) [Claims] Claims: 1. Mainly comprises a vehicle reacted with a desensitizer, a filler and a polyamidoamine, and has a viscosity of
A desensitizing ink for lithographic printing without water with a poise of 500 poise or more.