JPS647112B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a W/O that can be used without dampening water for high-speed lithographic rotary printing such as general commercial printing and newspaper printing.
Regarding type emulsion inks, in particular, by using an amphoteric surfactant as a stabilizer for dispersing the aqueous solution in the ink, the emulsion can be stabilized, and at the same time, plate wear, which is a drawback of conventional emulsion type lithographic inks, can be prevented. The purpose is to reduce

In normal lithographic printing, the property of phase separation between oil-based printing ink and water is utilized. Printing is performed by alternately supplying ink and dampening water onto the plate. However, this method required skill in balancing the ink and dampening water, and only a highly experienced printer could print printed matter of a certain quality over a long period of time. . In order to solve this problem, water is pre-contained in the ink to create a so-called W/
O-type emulsion ink is used, and by printing with this emulsion ink, the use and control of dampening water is omitted as a method of direct lithographic printing. In addition, emulsion formation of lithographic ink is also carried out for the purpose of preventing misting, preventing flammability, and the like.

As emulsion inks for lithographic printing used for the above-mentioned purposes, the following have been proposed in the past.

(b) 100 parts by weight of a wetting liquid consisting of a mixture of polyhydric alcohol, water, and auxiliary agents such as inorganic acids or their salts and nonionic surfactants, based on 100 parts by weight of oil-based ink of 5 to 60 poise. Emulsion ink prepared by mixing ~250 parts by weight
106305).

(b) Emulsion ink made by adding 0.1 to 2 parts by weight of a nonionic activator of HLB 7 to 13 and 80 to 120 parts by weight of an aqueous component consisting of water and alcohol to 100 parts by weight of an oil-based ink (JP-A No. 55-5946) Public bulletin).

(c) A moisturizing liquid containing oxycarboxylic acids having 2 to 6 carbon atoms, phosphoric acid or its salts, polyhydric alcohols, and water is mixed into a pigment dispersion paste consisting of a pigment, vehicle, diluent, and other additives. Emulsion ink made by Sasete (Special Publication 1984)
Publication No. 18754).

However, it has been found that these emulsion inks generally cause plate wear as printing continues. The reason for this is related to the fact that currently, PS plates are mostly used in the production of printing plates for lithographic printing.

That is, PS plates can be roughly divided into, for example, novolac-type phenolic resins containing O-naphthoquinonediazide-based photosensitizers, positive-working PS plates made of acrylic polymers, etc., and diazo resins, azide resins, polyvinyl cinnamate, photosensitive There are negative PS plates made of polyester, polycarbonate, polysulfonate, etc., but in printing plates obtained from any type of PS plate, the resin layer that becomes the image area is generally made of alkali, alcohol, or anionic surfactant. It has the property of being slightly dissolved by nonionic surfactants, etc. Therefore,
When using emulsion inks such as those mentioned above that contain these chemicals as wetting ingredients or component stabilizers, even if the content is minute, the surface of the printed area of the plate will gradually deteriorate over long periods of printing. This results in the phenomenon that the ink is no longer attached, and the printed area itself is lost from the plate.

In view of the above-mentioned problems with conventional emulsion inks, the present inventors conducted research to find an emulsion ink for lithographic printing that causes almost no wear on the plate even during long-term printing, and found that the emulsion is stable. It has been found that the use of amphoteric surfactants as agents is very effective. The W/O type emulsion ink for lithographic printing of the present invention is based on such knowledge, and more specifically, an aqueous solution containing an inorganic acid or its salts is added to an oil-based ink using an amphoteric surfactant as a stabilizer. It is characterized by being emulsified and dispersed.

The present invention will be explained in more detail below. In the following description, "%" and "part" are based on weight unless otherwise specified.

The oil-based ink serving as the base of the emulsion ink of the present invention includes rosin-modified phenolic resin,
Petroleum resins, maleic acid resins, ester resins such as ester gum, vegetable oil-modified alkyd resins, hardened rosin, tall oil pitch, gilsonite, and other resin components are combined with vegetable oils such as linseed oil, tung oil, safflower oil, dehydrated castor oil, or minerals. The pigment is mixed and dispersed in a vehicle obtained by dissolving it in oil. Depending on the selection of resin, oil, etc. mentioned above, the final ink can be 10 to 100 poise for high-speed lithographic rotary newspaper printing, 50 to 150 poise for general lithographic rotary newspaper printing, and 50 to 150 poise for general lithographic rotary newspaper printing.
Lithographic inks of various viscosities such as 100 to 600 poise are prepared. The inks of the present invention are particularly suitable for use as low viscosity emulsion inks for high speed lithographic rotary newspaper printing, where petroleum resins, hardened rosins, ester gums, tall oil pitches and gilsonites are selected. It is preferred to use a vehicle in which the resin is dissolved in mineral oil.

As pigments, those normally used in lithographic inks can be used as they are, such as carbon black, disazo yellow, watching red, carmine 6B, phthalocyanine blue,
Organic pigments such as phthalocyanine green, ultramarine blue, and miloly blue, and dye lakes such as rhodamine B, malachite green, methyl violet, and Victoria blue can be used.

According to the invention, such oil-based ink 100
% of an aqueous solution containing an inorganic acid or its salts using an amphoteric surfactant as a stabilizer.
Emulsify and disperse ~120 parts.

Various types of amphoteric surfactants are known, but when classified by anionic active group,
Compared to the sulfuric acid ester type, sulfonic acid type, etc., the carboxylic acid type is preferable because it is water-soluble and less corrosive to the plate. Activators of this type include, for example:
formula (Here, R ¹ is a C ₁₂ to C ₁₈ alkyl group, R ² is a methyl or ethyl group)); Formula R ¹ - (NH-CH ₂ - CH ₂ ) ₂ NH CH ₂ COOH... (5) (R ³ ―NH―CH ₂ ―CH ₂ ) ₂ N―CH ₂ ―COOH
…(6) Glycine type represented by (here, R ¹ is the same alkyl group as above, R ³ is, for example, a C ₈ octyl group); formula R ¹ —NH ₂ —CH ₂ —CH ₂ —COOH…(7) The alanine type represented by is preferably used for the purpose of the present invention. Among these, from the viewpoint of emulsion stability and non-solubility in print line areas,
Betaine types, particularly those represented by formula (1), are preferred, and among these, those in which R ¹ is a C ₁₆ to _{C 18} alkyl group are most preferred. These amphoteric surfactants are
0.05 to 5 parts, especially 0.1 to 5 parts per 100 parts of oil-based ink
Preferably, it is used in a range of 2 parts.

Along with the above-mentioned amphoteric surfactants, W/
Nonionic surfactants such as fatty acid esters of polyoxy compounds (polyols) used in O-type emulsion inks or polyethylene oxide condensates can also be used, but in order to avoid wear and tear on the printing lines, The amount used is preferably 0.1 part or less, particularly 0.05 part or less, per 100 parts of oil-based ink.

The inorganic acid or its salt contained in the aqueous solution dispersed in the oil-based ink is added to prevent staining of the plate surface, and usually, the inorganic acid or its salt contained in the fountain solution is used as is. Specifically, phosphoric acid including orthophosphoric acid, metaphosphoric acid, and pyrophosphoric acid, inorganic acids such as silicic acid including metasilicic acid, orthosilicic acid, and pyrosilicic acid, and water-soluble alkali metal salts thereof such as sodium salts and potassium salts. etc. are used. These inorganic acids or salts are preferably added in an amount of 0.01 to 2.0% based on 100 parts of oil-based ink. However, from the viewpoint of plate wear, it is not preferable to add a large amount of 3.0% or more.

The ink of the present invention preferably contains 50 to 120 parts of water per 100 parts of the oil-based ink.
At this time, if the amount of water added exceeds 100 parts, dispersion may become poor. In such a case, it is preferable to add an extender pigment in an amount that accounts for 1.0 to 20%, particularly 2.0 to 10.0%, of the oil-based ink because it stabilizes the dispersion of water. Extender pigments used as such dispersion stabilizers are treated with resin acids, fatty acids, surfactants, etc. and have an average particle size of, for example, 0.03~
Calcium carbonate for printing ink of 0.04μ or calcium carbonate with an average particle size of 1 to 3μ without surface treatment is preferably used, as well as alumina white, barium sulfate, magnesium carbonate, calcium silicate, silicon dioxide, organic bentonite,
Extender pigments that are conventionally added to inks, such as finely powdered silica, can generally be used.

In addition to the above-mentioned components, additives that are normally added to this type of ink can be added to the emulsion ink of the present invention in usual amounts. Such additives include, for example, viscosity-imparting agents for aqueous solutions such as polysaccharides (e.g. gum arabic), polyhydric alcohols; phthalate esters such as dioctyl phthalate, citric acid esters, adipate esters, tricresyl phosphate. plasticizers such as phosphoric acid esters such as tridecyl alcohol, ethylene glycol monoethyl ether, and diethylene glycol monoethyl ether; other examples include wax, liquid paraffin, metallic soap, lecithin, silicone oil, and the like.

Next, one embodiment of the method for producing the lithographic printing emulsion ink of the present invention using the above-mentioned components will be described.

(b) First, when using multiple vehicles in combination, select each resin, vegetable oil, and mineral oil as necessary, and dissolve them by stirring under heating. Next, predetermined pigments, extender pigments, and auxiliary agents are added to these vehicles, and predispersion is performed by high-speed stirring with a dissolver, followed by sand grinder, shot mill, and
Disperse using a printing ink paste dispersion machine such as a book roll, attritor, or ball mill.

(b) Next, an amphoteric surfactant is added and mixed using a dissolver or homo mixer to emulsify and disperse.
Further, an aqueous solution of an inorganic acid or its salt as an antifouling agent is added as required, and an aqueous solution of a viscosity imparting agent such as gum arabic is added, and the mixture is further mixed using a dissolver or a homomixer.

(c) The water in the ink then turns into the oil-based ink obtained in (a).
Add tap water in an amount of 50 to 120 parts per 100 parts, and mix with a dissolver or homomixer until the whole is homogeneous.

The emulsion ink of the present invention obtained in this way has a viscosity adjusted in the range of 10 to 600 poise depending on the purpose, and is suitable for high-speed rotary newspaper printing, general lithographic rotary newspaper printing, or general lithographic commercial printing. Used as a lithographic printing ink that does not require dampening water. However, if the number of printed areas is particularly small, a small amount of dampening water may be used if necessary.

As described above, according to the present invention, by using an amphoteric surfactant as a dispersion stabilizer in an emulsion ink for lithographic printing that substantially eliminates the need for dampening water, it is possible to improve the stability of lithographic printing plates from PS plates. An emulsion ink with reduced wear and tear is provided.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 Black ink base (A) Carbon black (Mitsubishi Kasei) 15 parts Miloly Blue (Dainichiseika) 3〃 Shirotsuka DD ^*1 (Shiraishi Industries) 8〃 Petroleum resin varnish *2 28〃 Gilsonite varnish *3 12〃 Linseed oil No. 3 varnish 4 Diana Visol No. 2 30 100 parts *1 Rosin coated calcium carbonate *2 Petroleum resin varnish Neopolymer 120 (Nippon Oil) 25 parts 60 spindle oil (Idemitsu Kosan) 75 100 parts *3 Gil Sonite varnish Gilsonite 20 parts 60 Spindle oil 80 parts 100 parts The above blended composition was kneaded with a sand mill to disperse pigment particles to 5 μm or less to prepare a black ink base (A) (viscosity 20 poise).

Next, a W/O type emulsion ink having the following composition was obtained based on the above black ink base (A).

Black ink base (A) 100 parts Gum arabic 50% aqueous solution *4 2. Sodium phosphate 30% aqueous solution *5 1. Ampholytic surfactant (alkyl betaine type *6)
１〃Tap water 80〃 185 parts *4 Gum arabic 50% aqueous solution Gum arabic 50 parts Water 50〃 100 parts *5 Sodium phosphate 30% aqueous solution Sodium phosphate 30 parts Water 70〃 100 parts *6 Amhitol 24B Kao Atlas Co., Ltd.
(Alkylbentine type) In other words, add gum arabic aqueous solution, sodium phosphate aqueous solution, and amphoteric surfactant to 100 parts of black ink base (A) and mix with a homogenizer, then add 80 parts of tap water and mix again with a homogenizer. A W/O type emulsion ink that is stable at room temperature was obtained.

Using this ink, patterns were printed using an offset sheet-fed printing machine (Heidel KORD model) under the following conditions.

Printing speed: 6,000 sheets/hour Plate material: PS plate (O-naphthoquinone diazide resin) Paper: Newspaper paper (Oji Paper) 10,000 sheets could be printed without using any dampening water during printing. In particular, no stains in the non-printed areas or wear and tear on the plate were observed.

Example 2 Black ink base (B) Carbon black (Mitsubishi Kasei) 15 parts Miloly Blue (Dainichiseika) 2〃 Shirotsuka CC (Shiraishi Kogyo *7) 5〃 Phenol resin varnish *8 13〃 Petroleum resin varnish 15〃 Gilsonite Varnish 15〃 Linseed oil No. 7 varnish 5〃 Diana Visol No. 2 30〃 100 parts *7 Fatty acid treated calcium carbonate *8 Phenol resin varnish Rosin modified phenolic resin
38 parts Arakawa Hayashisan (Tamanol) 362 Linseed oil 10 parts Spindle oil 51 Aluminum chelate 1 100 parts The above blended composition was kneaded with a sand mill to disperse pigment particles to 5μ or less to prepare a black ink base (B). (viscosity 20 poise).

Next, based on this black ink base (B), the following components were mixed in a dissolver (1200 rpm) to obtain a stable W/O type emulsion ink.

Black ink base (B) 100 parts Gum arabic 50% aqueous solution 2. Sodium phosphate 30% aqueous solution 1. Ampholytic surfactant (alkyl betaine type *9)
1 Nonionic surfactant 0.1 Tap water 90 194.1 parts *9 Amphitol 86B Kao Atlas Co., Ltd.
(Alkyl betaine type) Using this ink, 10,000 sheets were printed using an offset sheet-fed printing machine (Heidel KORD) in the same manner as in Example 1 without applying dampening water.

As a result, no stains in the non-printed areas or wear and tear on the PS plate were observed.

Example 3 Black ink base (C) Carbon black 18 parts Neolite SA100 5 Miloly blue 2 Phenol resin varnish 24 Petroleum resin varnish 23 Gilsonite varnish 5 Spindle oil 15 Alkaline blue toner 1 Linseed oil No. 5 varnish 7〃 100 parts The above blended composition is kneaded in a three-roll mill to disperse pigment particles to a size of 5μ or less to form a black ink base (C).
(viscosity 70 poise).

Next, based on this black ink base (C), the following components were mixed in a dissolver to obtain a stable W/O type emulsion ink.

Black ink base (C) 100 parts Gum arabic 50% aqueous solution 2〃 Sodium phosphate 30% aqueous solution 1〃 Amphoteric surfactant *10 1〃 Nonionic surfactant (HLB10.5) 0.05 part Tap water 90〃 194.05 parts * 10 Anhitor 86B Kao Atlas
(Alkyl betaine type) Using this ink, 10,000 sheets of newsprint paper (Jujo Paper Co., Ltd.) were printed using a PS plate without dampening water using an offset sheet-fed printing machine (Heidel KORD).

As a result, as in Examples 1 and 2, printed matter was obtained without any particular wear and tear on the plate and with no stains in the non-image areas.

Comparative Example 1 Using the same black ink base (B) as in Example 2, a W/O type emulsion ink having the following composition was obtained.

Black ink base (B) 100 parts Nonionic activator (HLB = 10.5) (polyoxyethylene alkyl ether) 1. 30% sodium phosphate aqueous solution 2. Glycerin 20. Water 80. 203 parts Use this ink to print offset sheets. Pattern printing was performed using a leaf printing machine (Heidel KORD model) under the following conditions.

Printing speed: 6000 sheets/hour Material
PS plate (O-naphthoquinone diazide resin) Paper Newspaper paper (Oji Paper) From around 4,000 sheets after printing started, wear and tear on the plate was observed although it did not appear on the printed matter, and from around 6,000 sheets, the ink became worse overall. The transferability became worse and the printed surface became pale. Furthermore, when printing 10,000 sheets, there were some areas where the ink did not adhere. Additionally, the printing area of the plate was severely worn out.

Claims (1)

[Scope of Claims] 1. A W/O emulsion ink for lithographic printing, characterized in that an aqueous solution containing an inorganic acid or its salts is emulsified and dispersed in an oil-based ink using an amphoteric surfactant as a stabilizer. 2. The emulsion ink of item 1 above, further comprising an extender pigment as an emulsion stabilizer.