JPS6150111B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink composition for dry lithographic printing that has excellent fluidity and on-press stability.

In planographic printing, which is the mainstream of current printing,
Taking advantage of the property that water and oil-based ink repel each other, a plate consisting of a hydrophilic non-printing area and a lipophilic printing area is used, water is attached to the hydrophilic non-printing area, and the other side is lipophilic. Printing is carried out by applying oil-based ink to the image area, and then transferring the oil-based ink adhering to the image area to the substrate to obtain the desired printed material.

However, in this lithographic printing method,
It is difficult to control the dampening water, which serves to prevent ink from adhering to non-print areas, and the use of dampening water is one of the major technical obstacles in terms of printing suitability and printing effectiveness. ing. Therefore, various attempts have been made to perform dry lithographic printing using lithographic printing plates that do not require dampening water. The newest and most practical method for dry lithography is to print using a lithographic printing plate with a non-stick thin film of silicone rubber etc. on the non-image area. It is reported that it is possible to print with regular oil-based ink without the need for dampening water.
However, in practice, it has been found that printing using conventional oil-based inks is undesirable because of its inadequate printability, resulting in background smudges. To improve this, methods have been taken such as improving the cohesive force of the ink and increasing the ink tack, or adding organopolysiloxane or the like to the ink as an adhesion energy reducing agent. However, when such a method is used, although background smudge is improved, it has been found that there are problems such as insufficient ink fluidity and poor on-press stability due to the tendency of phase separation of the composition. .

The inventors of the present invention have conducted intensive studies to solve the above problems without impairing stain resistance, and have found that it is effective to add compounds having polar groups such as esters to these inks. Heading, we arrived at the present invention.

That is, the present invention provides a dry method characterized by containing 0.1 to 4% by weight of one or a mixture of two or more selected from aliphatic esters, ethers, aldehydes, and ketones having a boiling point of 150°C or higher. This is an ink composition for lithographic printing.

The esters used here include acetic acid,
Organic acids such as propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, cyclohexanecarboxylic acid, benzoic acid, etc. Organic dicarboxylic acids such as monocarboxylic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, or inorganic acids such as phosphoric acid and phosphorous acid. Monohydric alcohols such as methanol, ethanol, propanol, butanol, amyl alcohol, hexyl alcohol, octanol, decyl alcohol, lauryl alcohol, stearyl alcohol, oleyl alcohol, cyclohexanol, benzyl alcohol, ethylene glycol,
1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, dihydric alcohols such as diethylene glycol, trihydric alcohols such as glycerin, trimethylolpropane, tetrahydric alcohols such as pentaerythritol, 6-hydric alcohols such as sorbitol, etc. Examples include reaction products with alcohols. The acid preferably has no unsaturated bonds in its molecule. Examples of ethers include dioctyl ether, dilauryl ether, distearyl ether, and the like.

Examples of aldehydes and ketones include lauryl aldehyde, myristyl aldehyde, dihexyl ketone, dioctyl ketone, and dilauryl ketone.

These esters, ethers, aldehydes, and ketones preferably have a molecular weight of 1000 or less, and each can be used alone or in combination of two or more. The amount of these additives is determined depending on the ink material used, but it is preferably in the range of 0.1 to 4.0% by weight based on the total weight of the ink composition.

In the ink composition used here, known vehicles for ink compositions are used, such as drying oil, rosin, rosin ester, phenolic resin, rosin-modified phenolic resin, alkyd resin, acrylic resin, epoxy resin, amino alkyd. Resin, vinyl resin, etc. can be used.

Furthermore, as the colorant, those used in conventional ink compositions such as inorganic or organic pigments can be used.

Furthermore, other additives include, for example,
Waxes, greases, desiccants, auxiliary desiccants, thickeners, dispersants, fillers, and other known substances can be used.

When adding esters, ethers, aldehydes, and ketones, they can be added and mixed into the finished ink, or they can be added to a solvent or vehicle as soon as possible during an intermediate step in the ink manufacturing process. They may be added and mixed, and then an ink may be made using these as a base.

Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 Ink-A prepared by adding dimethylpolysiloxane oil and Ink-B prepared by adding and mixing 3% by weight of diethylene glycol dibutyl ether to this ink were each sprayed with dampening water onto the plate surface using a Komori Sprint lithographic printing machine. Printing was carried out using a dry lithographic plate having a non-adhesive layer made of silicone rubber without supplying any.

As a result, when Ink-A was used, the transfer deteriorated after 4,000 sheets, and printing at a practical level could not be obtained. On the other hand, ink B to which diethylene glycol dibutyl ether was added could be printed on 20,000 sheets without causing any scumming, and had good printing effects and printability.

Formula of Ink-A Carbon black for printing ink 17.0 parts Phthalocyanine blue 8.0 parts Rosin-modified phenolic resin varnish C 60.0 parts Wax compound 7.0 parts Cobalt naphthenate salt (metal concentration 7.5%) 1.0 part Manganese naphthenate salt (metal concentration 6.5%) ) 1.0 part dimethylpolysiloxane oil (SH200 manufactured by Toray Silicone Co., Ltd. 10,000 CS/25°C) 1.5 parts spindle oil 4.5 parts Total 100.0 parts Incometer Tack 11.0 (400 rpm, 1 minute, 30°C) Rosin-modified phenolic resin varnish Formula for C Rosin-modified alkylphenol resin 40.0 parts Castor oil 10.0 parts Dehydrated castor oil 10.0 parts Spindle oil 38.0 parts Aluminum octoate 2.0 parts Total 100.0 parts Prescription for Ink-B Ink-A 97.0 parts Diethylene glycol dibutyl ether 3.0 parts Total 100.0 parts Incometer・Tack 10.3 (400 rpm, 1 minute, 30°C) Example 2 Red dry lithographic ink “Aquares HT” manufactured by Toyo Ink Co., Ltd. containing organopolysiloxane and 4% by weight of dibutyl sebacate. The added Ink-D was printed on a Komori Sprint lithographic printing machine using a dry lithographic plate having a non-adhesive layer made of silicone rubber without supplying dampening water to the plate surface.

As a result, in order to make the solid density of "HT" red 1.4 (measured with a Gretag reflection densitometer),
While the ink film thickness on the roller needed to be 13 microns, Ink-D containing dibutyl sebatate was able to produce the same solid density at 6 microns.
Also, when the solid density becomes constant, turn off the printing machine.
After stopping for 30 minutes, we started printing again and measured the number of sheets of paper required for the solid density to recover to the density before stopping. With Ink-D containing dibutyl sebatate, it was 200 sheets before stopping. While the concentration was restored to normal, ``HT'' red required 500 sheets.

In addition, ink containing dibutyl sebatate
D did not have background stains even after printing 20,000 sheets.

“Aquares HT” Red Incometer Tak 11.1 (400 rpm, 1 minute, 30°C) Ink-D “Aquares HT” Red 96 parts Butyl sebatate 4 parts Total 100 parts Incometer Tak 10.4 (400 rpm, 1 minute, 30°C ) Example 3 Printing was carried out using a dry lithographic plate using a red dry lithographic ink "DryOcolor" manufactured by Dainippon Ink Co., Ltd. and an ink E in which 3% by weight of trilauryl phosphite was added to the same.

As a result, we stopped the printing press for 30 minutes when the solid density became constant, started printing again, and measured the number of sheets of paper required for the solid density to recover to the density before stopping. Ink-E containing trilauryl acid recovered to the pre-stop density after 250 sheets, while "DryOcolor" red
600 pieces were needed.

Ink-E containing trilauryl phosphite did not cause background smearing even after printing 10,000 sheets.

“Dry Ocolor” Red Incometer Tak 8.6 (400 rpm, 1 minute, 30℃) Ink E “Dry O Color” Red 97 parts Trilauryl phosphite 3 parts Total 100 parts Incometer Tak 8.1 (400 rpm, 1 minute , 30℃)

Claims (1)

[Claims] 1 0.1 to 4% by weight of one or a mixture of two or more selected from aliphatic esters, ethers, aldehydes, and ketones with a boiling point of 150°C or higher
An ink composition for dry lithographic printing, comprising: