JPS64240B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aqueous overcoating liquid composition to be applied onto a wet ink coating to accelerate the drying of oil-based inks and prevent set-off. Generally, when coloring or painting is applied to the surface of paper, plastic film, wood, or metal layers by printing or painting, the purpose of applying coloring or painting to the surface of paper, plastic film, wood, or metal layers is to accelerate the drying of the printed or painted layer or to improve the surface properties of the painted film. It is common practice to apply an overcoat to the surface. In this case, the coating liquid that forms the surface layer (generally a resin solution that does not contain a colorant) is usually one in which the resin is dissolved in an organic solvent, or one in which the resin is dissolved in water or a mixture of water and alcohol. The latter can be roughly divided into two types, and the latter is generally called ``aqueous overcoating liquid''.

Oil-based printing inks used for planographic printing, letterpress printing, bag making printing, etc. generally contain drying oil, resin, mineral oil, etc. as a vehicle. When such oil-based printing ink dries, part of the mineral oil and drying oil penetrates into the paper, leaving a slightly viscous film on the paper (set), and then unsaturation in the drying oil The process progresses as the fatty acid ester absorbs oxygen from the air and undergoes oxidation and polymerization reactions to harden. Such drying of the ink by oxidative polymerization proceeds using a metal salt of a fatty acid contained in the ink as a catalyst. However, the disadvantage of this kind of oil-based printing ink is that it takes a long time to dry, and especially when printing paper is piled up in stacks for sheet-fed printing, it takes even longer to dry because air circulation is blocked. This causes extremely undesirable phenomena such as set-off, blocking, etc. For this reason, in normal sheet-fed printing, methods such as uneconomical slatting or dispersing spray powder (starch) at the paper discharge section of the printing machine are used. However, the method of dispersing spray powder has disadvantages in that the working environment deteriorates and the smoothness of the printed surface is lost. On the other hand, in recent years, attempts have been made to prevent set-off by applying an aqueous overcoating liquid on a wet ink coating for the purpose of complete stacking without dispersing spray powder.
However, although this method has the effect of reducing set-off, the wet ink film of the underprint covered with the aqueous overcoating liquid is further cut off from oxygen supply, and the drying time is longer than that when the aqueous overcoating liquid is applied. It may be slower than it would be without it, but it won't be faster.

An object of the present invention is to shorten the time required for post-processing, for example, cutting, by promoting drying of the ink film without causing roughening of the printed surface.

As a result of intensive research for the above-mentioned purpose, the present inventors found that
Provided is an aqueous overcoating liquid composition containing a polydentate ligand compound having the effect of promoting drying by oxidative polymerization of an oil-based ink containing a fatty acid metal salt,
We have found that applying this onto a wet coating of ink is highly effective.

The overcoating liquid composition of the present invention is based on the above-mentioned findings, and more specifically, it is an aqueous overcoating liquid composition for coating on a wet coating film of an oil-based ink containing a metal salt of a fatty acid. , characterized in that a polydentate ligand compound capable of reacting with the metal salt of the fatty acid to form a complex is dispersed in an aqueous medium containing water or a mixture of water and alcohol as a main component. That is.

It is known that the above-mentioned polydentate ligand compounds form a more effective catalyst system for oxidative polymerization reactions than the metal salts of fatty acids alone. Therefore, it is conceivable to add this to the oil-based ink together with a metal salt of a fatty acid.
However, in the present invention, the reason why the polydentate ligand compound is included in the aqueous overcoating liquid without taking such measures is that when the polydentate ligand compound and the fatty acid salt of the metal are included in the ink. This is because the following inconveniences are recognized.

(b) Some types of ink, such as yellow ink, undergo discoloration during long-term storage.

(b) Depending on the application, it may not be necessary to accelerate drying by oxidative polymerization to that extent, but it is uneconomical to uniformly include a polydentate ligand compound.

(c) Since the amount added is extremely small, about 0.01% of the ink, extremely accurate measurement is required, making it difficult to mix the ink.

Additionally, the method of including a polydentate ligand compound in an aqueous overcoating solution and applying it onto a wet coating of ink has the following additional effects.

(d) An aqueous dispersion medium for the polydentate ligand compound is more effective in accelerating drying.

(e) Differences in drying speed due to uneven thickness of the ink coating can be alleviated.

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

Examples of the polydentate ligand compound used in the present invention include hexahydrodiazine, 1,2-diazine, 1,3-diazine, 1,4-diazine, phthalazine, bipyridine, 2,2'-dimethylbipyridine, 2,2'-diethylbipyridine, 5,5'-methyl-2,2'-bipyridine, 2,3-dimethyl-
1,4-diazine, 2,3-diethyl-1,4-
Diazine, terpyridine, 2,2″-dimethylterpyridine, orthophenanthroline, orthophenanthroline hydrochloride, 3-carboxy-4-hydroxy-5-methoxy-1,10-phenanthroline, triazine, 2,2 '-Biquinoline, 2-oxyazobenzene, salicylaldehyde, 8-oxyquinoline, phthalonitrile, 1,3-diphenylguanidine, dimethylglyoxime, salicylaldoxime, dithiodiogizamide, triethylenetetramine, N,N', N″,N-tetrasalicylidenetetraaminomethylethane, N,N′-
Examples include bis(salicylidene)ethylenediamine, chlorophyll, hematoporphyrin, and the like.

These polydentate ligand compounds are dispersed in an aqueous medium, more preferably in solution. In the present invention, the aqueous medium means one containing water or a mixture of water and alcohol as a main component. As will be described later, in addition to water or alcohol, this aqueous medium contains polyvinyl alcohol, methyl cellulose, hydroxypropyl cellulose, casein, gelatin, dextrin, and water-soluble acrylic resin in order to adjust adhesion and stickiness. , acrylonitrile resin, styrenated acrylic copolymer resin, etc. can also be dissolved or suspended and dispersed. For example, by dissolving the above-mentioned polydentate ligand compound in an aqueous medium containing an alcohol such as methanol, ethanol, isopropyl alcohol, butanol, methyl cellosolve in an amount of about 1 to 5 times the amount of water. Then, an aqueous overcoating solution can be prepared. The polydentate ligand compound is desirably contained in the overcoating liquid in a proportion of 0.1 to 5%. If it is less than 0.1%, the effect is poor, and if it is more than 5%, it may act as a drying inhibitor. In addition, approximately 3 to 20% of a water-soluble resin can be added to the aqueous overcoating solution to improve its coating suitability, as well as wax to provide coating strength and surfactants to stabilize the emulsion. , heat resistance improver, antifoaming agent,
Other ingredients can also be added as needed.

The oil-based ink whose drying is to be promoted using the aqueous overcoating liquid of the present invention is not particularly different from ordinary ink except that it contains a metal salt of a fatty acid. That is, a desired color tone is prepared in a vehicle in which resins, mineral oils, solvents, plasticizers, surfactants, cellulose, rubber derivatives, etc. are added as necessary to a drying oil or a modified drying oil as a curing component. It is made by adding organic or inorganic pigments, and further auxiliary agents such as color density adjusting agents and surfactants as necessary.Here, even when using only the above-mentioned vehicle as an overprint varnish, printing ink shall be included in the This is because the method of the present invention can also provide a drying accelerating effect on overprint varnishes.

As the oil-based printing ink, one containing metal salts of fatty acids is used. Examples include cobalt, manganese, iron, calcium, vanadium, cerium,
Naphthenic acid of metals such as copper, zinc, zirconium, etc.
Examples include salts of saturated or unsaturated fatty acids such as 2-ethylhexanoic acid, oleic acid, linseed oil fatty acid, tung oil fatty acid, and tall oil acid. Any material can be used as long as it forms and promotes the oxidative polymerization reaction. The amount of these additions is not particularly different from the usual case. It is assumed that the constituent metals of the metal salt of the fatty acid in the ink are dissociated by the action of the aqueous medium, and a complex is formed between the dissociated metal ion and the polydentate ligand.

After printing with an oil-based printing ink containing a metal salt of a fatty acid as described above according to a conventional method such as offset sheet-fed printing, offset rotary printing, letterpress printing, etc., the aqueous overcoating liquid of the present invention is applied to the printed surface with a brush. Or roller coating, or
It is applied by spraying or the like and brought into contact with printing ink, and promotes curing and drying of the ink through cooperation with fatty acid metal salts in the printing ink.

The amount of the aqueous overcoating liquid to be applied is determined in relation to the drying speed, but the amount of polydentate ligand compound is usually 0.005 to 0.5 g/m ² , preferably 0.01 to 0.05 g/m ² It is applied at a rate in the range of .

In this way, the coating film of the printing ink coated with the aqueous overcoating liquid is accelerated in curing and strengthened, and wrinkles and stains during cutting are significantly improved.

The application of conventional aqueous overcoating liquids does not cause problems such as set-off and blocking due to stacking, but does not have the effect of promoting oxidative polymerization reactions. Therefore, it takes 4 to 10 hours to cut the paper after printing, but when the aqueous overcoating liquid of the present invention is used, the problem of curling during cutting is completely eliminated in 1 to 2 hours.

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

Example 1 An oxidative polymerization type ink vehicle was prepared using the following formulation.

(1) Rosin-modified phenolic resin (Tamanol 340 manufactured by Arakawa Chemical) 38 parts (2) Linseed oil 19〃 (3) Tung oil 10〃 (4) 540 solvent (manufactured by Nippon Oil Co., Ltd.) ^* 33〃 100〃 * 80% paraffin type Hydrocarbon 540〓Petroleum distillate Vehicle is prepared by blending components (1) to (3) and heating to 240℃.
The mixture was kept for 30 minutes, then component (4) was added, the heating source was turned off, and the mixture was left to cool.

To the thus obtained vehicle, 1.5 parts of aluminum octylate was added to 100 parts of the vehicle, and after uniform mixing, the temperature was raised to 140°C and kept at this temperature for 15 minutes to effect gelation. Using the gel varnish thus prepared, an oxidative polymerization type ink was prepared using the following formulation.

Gel varnish 80.0 parts Carmine 6B#1 (manufactured by Dainichiseika, water-soluble azo pigment) 18.0〃 Polyethylene wax 1.85〃 Manganese 2-ethylhexanoate 0.1〃 Cobalt 2-ethylhexanoate 0.05〃 100.00〃 Separately, the following formulation An aqueous overcoating liquid (liquid A) was prepared.

Jyonkryl 74F (manufactured by Jyonson, a 45% aqueous suspension of styrenated acrylic copolymer resin) 70 parts Jyoncryl 61 (manufactured by Jyonson, a 25% aqueous suspension of styrenated acrylic copolymer resin) 30〃 100〃 Further below A multidentate ligand compound solution was prepared by blending.

Orthophenanthroline 30 parts Isopropyl alcohol 70〃 100〃 The above aqueous overcoating liquid (Liquid A)
A 2% polydentate ligand compound solution was added to the solution to prepare an aqueous overcoating solution (solution B). Next, the above-mentioned oxidative polymerization type ink was printed solidly on 43.5 kg / 4.6 size top coated paper (manufactured by Kanzaki Paper Industries) using an RI tester (manufactured by Mei Seisakusho) with a 4-part roller in 0.2 cc increments, and immediately after the water-based The overcoating liquids A and B were each weighed at approximately 4 g/m ² (liquid standard) using a hand proofing furnace (manufactured by Pamarco).
After coating at a ratio of , the drying time was measured using a drying tester (manufactured by Toyo Seiki Seisakusho) and compared. The drying time was 3 hours and 50 minutes when liquid A was applied, whereas it was 1 hour and 40 minutes when liquid B was applied.

Example 2 A multidentate ligand compound solution was prepared using the following formulation.

Bipyridine 30 parts Ethanol 70〃 100〃 5% of the above solution was added to the aqueous overcoating liquid (liquid A) described in Example 1 to prepare an aqueous overcoating liquid. Using this, the coating was applied in the same manner as in Example 1, and the drying time was measured. As a result, the drying time was 1 hour and 10 minutes.

Example 3 A multidentate ligand compound solution was prepared using the following formulation.

Phthalazine 20 parts Isopropyl alcohol 80〃 100〃 5% of the above additive liquid was added to the aqueous overcoating liquid (liquid A) described in Example 1 and applied in the same manner as in Example 1, and the drying time was measured. . As a result, the drying time was 2 hours and 15 minutes.
Furthermore, after 2 hours of printing, a force of 500 g/cm ² was applied to determine the degree of wrinkles during cutting and binding.The paper coated with liquid A left scratch marks, while the paper coated with liquid A left scratches.
All the items to which the liquid was applied were completely sticky and no scratch marks were observed.

Claims (1)

[Claims] 1. An aqueous overcoating liquid composition for coating on a wet film of an oil-based ink containing a metal salt of a fatty acid, in an aqueous medium containing water or a mixture of water and alcohol as a main component. 1. An aqueous overcoating liquid composition comprising a polydentate ligand compound capable of reacting with the metal salt of the fatty acid to form a complex.