JP3366716B2 - UV curable ink for printing stepped ball sheets - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention eliminates waste of ink in printing on a corrugated ball sheet and the like, and the next step is continuously performed immediately after printing to improve productivity and reduce cost. The present invention relates to a water-soluble UV-curable ink used in a printing method that enables printing.

[0002]

2. Description of the Related Art A conventional printing apparatus used for printing a corrugated ball sheet has a main roll (anilox roll) having fine irregularities formed on its surface and an auxiliary roll. The printing cylinder is in contact with the main roll, and the ink is poured by a pipe from above between the main roll and the auxiliary roll. -It collects with Le. This ink reservoir causes the ink to enter the concave portion of the main roll, and the auxiliary roll squeezes out excess ink, forms a uniform ink film on the main roll, and sends it to the plate. .

With this auxiliary roll, a strong shear stress is applied when the ink is squeezed out, and a large amount of heat is generated.
Conventionally, the ink used in this apparatus is a water-based ink using low boiling water and a water-soluble solvent (alcohol, glycol, etc.) as a solvent in its composition, or JP-A-5-13.
It is a water-soluble UV-curable ink containing 1 to 25% by weight of water in the ink as described in JP-A-8863.

In the method of printing on the stepped ball sheet using the above apparatus and ink, since the ink uses water and a water-soluble solvent, drying on the stepped ball sheet is fast. However, there is evaporation of low boiling point components on the printing machine, and the viscosity rises, so excess ink must be constantly circulated. Therefore, a device that constantly circulates the ink is required. In addition, when changing the color of ink, a large amount of ink is wasted, and measures to deal with it are a serious problem.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks of conventional inks, simplifies the printing apparatus, and makes the printing operation, switching work, etc. efficient. -It is intended to provide a water-soluble ultraviolet-curable ink for printing.

[0006]

The object of the present invention is to provide an ultraviolet-curable composition having a water-soluble component content of 50 to 100% and a viscosity of 1000 cps (25 ° C.) or less. , A water-soluble UV-curable ink characterized by not containing water and a water-soluble solvent.

The water-soluble UV-curable ink used in the present invention has a water-soluble component in the range of 50 to 100% and a viscosity of 1000 cps (25 ° C.) or less,
It is characterized by not containing water and water-soluble solvent at all. Its composition is (1) a photopolymerizable vinyl oligomer that is cured by irradiation with ultraviolet rays (2) a photopolymerizable vinyl monomer (3) a photopolymerization initiator (4) a polymerization inhibitor (5) a pigment A mixture of. In addition to the above, if necessary, a photosensitizer, an anti-friction agent, a gelling agent, an antifoaming agent,
A dispersant may be mixed as an auxiliary agent.

The photopolymerizable oligomer (1) is an epoxy acrylate, an epoxidized oil acrylate, a urethane acrylate, a polyester acrylate, a polyether acrylate, an acrylic alkyd, a diallyl phthalate. Well-known oligoacrylates such as epoxy resin are included, which contain hydrophilic groups such as hydroxyl group, carboxyl group, polypropylene group and amino group, and have a viscosity of 1500 cps.
(25 ° C) or less is preferable, and 1000 cps (2
It is more preferably 5 ° C. or less.

The photopolymerizable vinyl monomer (2) is
For example, 2-hydroxyethyl acrylate, 2-methoxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, polyethylene glycol ^# 300 diacrylate, polyethylene glycol. ^# 400 diacrylate, polyethylene glycol ^# 600 diacrylate, alkylphenoxy polyethylene glycol acrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, Water-soluble vinyl monomers such as N-vinylpyrrolidone, morpholine acrylate, and morpholinoethyl acrylate are included, and the viscosity is 150 cps.
(25 ° C) or less is preferable, and 100 cps (25
C.) or less is more preferable.

Examples of the photopolymerization initiator (3) include acetophenone-based compounds such as jetoxyacetophenone, hydroxyacetophenone and α-aminoacetophenone, benzoin-based compounds such as benzoinethyl ether and benzyldimethylketane, benzophenone-based compounds such as benzophenone, 2, A thioxanthone compound such as 4-diethylthioxanthone, methylphenylglyoxylate, an acylphosphine oxide, etc. may be used alone or in combination. The photopolymerizable vinyl oligomer of (1) is not particularly limited. ，
Those having good compatibility with the photopolymerizable vinyl monomer (2) are preferable. From odor and yellowing, at room temperature, acylphosphine oxide should be added to liquid hydroxyacetophenone.
What was melt | dissolved at 0-60 degreeC is more preferable.

The polymerization inhibitor (4) is hydroquinone,
Known examples include hydroquinone monomethyl ether, mono-t-butyl hydroquinone, phenothiazine and catechol.

The pigment (5) is an ordinary pigment for water-based ink, for example, a monoazo pigment, a disazo pigment, a quinacridone pigment,
Organic pigments such as naphthol-based and phthalocyanine-based pigments and inorganic pigments such as titanium dioxide, barium sulfate, calcium carbonate and carbon black can be used.

The blending amount of the above substances in the water-soluble UV-curable ink used in the present invention is not particularly limited, but it is necessary to have curability, detergency with water and a viscosity of 1000 cps (25 ° C.) or less. Therefore, the proportion of the water-soluble monomer (2) in the ink is preferably in the range of 50 to 90% by weight. If the water-soluble monomer is 50% by weight or less,
Poor detergency with water, the viscosity of the entire ink system is 1000
It is difficult to keep the temperature below cps (25 ° C) and it cannot be applied to the printing method.

The proportion of the photopolymerizable oligomer (1) in the ink is preferably 10 to 30% by weight. If it is less than 10% by weight, the curability is poor, and 30% by weight
Viscosity is 1000cps (25 ℃)
It is difficult to The proportion of the photopolymerization initiator (3) in the ink is 10% by weight or less, and it may be used in a proportion sufficient to cure the ink. The polymerization inhibitor of (4) is 0.01% in consideration of the storage stability of the ink.
It suffices to use it within a range of up to 0.2% by weight. The proportion of the pigment of (5) in the ink is preferably in the range of 8 to 20% by weight.

The above materials are used in the well-known parallel type bead mill (Dyanomill manufactured by WAB Co., Ltd., KDL-P) in the range of 50 to 60 ° C.
The water-soluble UV-curable ink manufactured by ILOT type, capacity 1.4 liters) has a viscosity of 1000 cps.
Because of the low viscosity (25 ° C) or less, the main roll and the auxiliary roll having fine irregularities formed on the surface are arranged opposite to each other, and the plate cylinder is brought into contact with the main roll to form a step ball sheet. It is possible to correspond to a printing method for printing on the same (the flexographic printing method). Further, since neither water nor a water-soluble solvent is used, there is no evaporation on the printing machine and no increase in viscosity occurs, so there is no need to circulate and flow the ink. Therefore, it is possible to eliminate waste of ink when changing colors of ink.

[0016]

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. Example 1. Poly ester acrylate (manufactured by Arakawa Chemical BEAMSET 750) 24 parts morpholine acrylate (Kojin manufactured Akumo) 55.95 parts DAROCUR -4265 (Chibagaiki - manufacturing photopolymerization initiator, 2-hydroxy-2-methyl-1-phenylpropane-1-one A mixture of 50 parts by weight and 2.4.6-trimethylbenzoyldiphenylphosphine oxide 50 parts by weight) 9 parts Polyethylene glycol octyl phenyl ether (Daiichi Kogyo Seiyaku Neugen EA112) 1 part Metoquinone (Hydroxynone monomethyl ether manufactured by Seiko Chemical Co., Ltd.) 0.05 Parts Yellow pigment (Riono-Ruiello-SS OW manufactured by Toyo Ink Co., Ltd.) 10 parts Total 100 parts The above compound was mixed and kneaded in the parallel bead mill to obtain an ink A having a viscosity of 600 cps (25 ° C.). .

Example 2. Aliphatic epoxy acrylate (BASF Laromer LR 8765) 23 parts Polyethylene glycol ^# 300 diacrylate (Daiichi Kogyo Seiyaku New Frontier PE-300) 31.95 parts 4-hydroxybutyl acrylate (Osaka Organic Chemical Industry 4-HBA) 25 parts Darocur-4265 9 parts Neugen EA 112 1 part Metoquinone 0.05 parts Rhino-Ruiello-SS OW 10 parts Total 100 parts Mix the above ingredients with a bead mill and knead the mixture. , Ink B having a viscosity of 550 cps (25 ° C.) was obtained.

Example 3. Epoxy acrylate (Beam-Set AQ-7 made by Arakawa Chemical Co., Ltd.) 27 parts 2-Hydroxypropyl acrylate (light ester HOP-A made by Kyoeisha Oil & Fat Co., Ltd.) 52.95 parts Darocur-4265 9 parts Neugen EA 112 1 part Metoquinone 0.05 parts Riono-Ruiello-SS OW 10 parts Total 100 parts The above ingredients were mixed and kneaded in a bead mill to obtain an ink C having a viscosity of 440 cps (25 ° C.).

Example 4. Chlorinated polyester acrylate (Ebecryl 584 made by Daicel UCB) 23 parts Morpholine acrylate (Akmo made by Kojin) 32.95 parts 4-Hydroxybutyl acrylate (4-HBA made by Osaka Organic Chemical Industry) 24 parts Darocure -4265 4.5 parts Vicure 55 (Akzo photopolymerization initiator, methyl phenylglyoxyate) 4.5 parts Neugen EA 112 1 part Metoquinone 0.05 parts Riono-Ruiello-SS OW 10 parts Total 100 parts Ink D having a viscosity of 660 cps (25 ° C.) was obtained by mixing and kneading with a Z-mill.

Comparative Example 1. Polyester acrylate (Beam set 750 manufactured by Arakawa Chemical Co., Ltd.) 40 parts Morpholine acrylate (Akmo made by Kojin) 39.95 parts Darocur-4265 9 parts Neugen EA 112 1 part Metoquinone 0.05 parts Riono-Ruiero SS OW 10 parts 100 parts in total The above ingredients were mixed and kneaded with a bead mill to obtain an ink E having a viscosity of 1210 cps (25 ° C.).

Comparative Example 2. Morpholine Acrylate (Akmo made by Kojin) 79.95 parts Darocur-4265 9 parts Neugen EA 112 1 part Metoquinone 0.05 parts Riono-Ruiello-SS OW 10 parts Total 100 parts Mixing the above-mentioned compounds with a bead mill Ink F was obtained with a viscosity of 400 cps (25 ° C.).

Comparative Example 3. In a four-necked flask equipped with a cooling device, 42 parts by weight of powdered diallyl phthalate resin (Daiso-Isodap manufactured by Daiso) and EO-modified trimethylolpropane triacrylate (Neoma-TA40 manufactured by Sanyo Kasei Co., Ltd.) were used.
1) 57.95 parts by weight of hydroquinone monomethyl ether
Add 0.05 parts by weight of tellurium and put in an oil bath at 120 ℃ for 3
It was dissolved by stirring for 0 minutes. The product thus obtained was used as varnish (1). Next, an ink having the following composition was produced using this varnish (1). Varnish (1) 24 parts 1.6 Hexanediol diacrylate (Kyoeisha Oil and Fat Light Acrylate 1.6 HX-A) 55.95 parts Darocur 4265 9 parts Neugen EA-112 1 part Metoquinone 0.05 parts Riono-Ruiello-SS OW 10 parts Total 100 parts The above mixture was mixed and kneaded with a bead mill to obtain an ink G having a viscosity of 390 cps (25 ° C.).

Comparative Example 4. Styrene acrylic copolymer resin 12 parts Rosin maleate resin 8 parts Water 15 parts Acrylic emulsion 20 parts Ethylene glycol 30 parts Diethanolamine 2 parts Polyethylene wax 3 parts Riono-Ruiello-SS OW 10 parts Total 100 parts As above Of different composition, currently manufactured by prior art methods,
The ink that has been put into practical use is called ink H. The viscosity of H was 440 cps (25 ° C.).

The eight kinds of inks A to H produced as described above were printed and evaluated by the following methods, and the results shown in Table 1 were obtained. Printing machine, using ISOWA production and new Saiwai Machine flexographic printing machine, using the anilox roll 165 lines / inch, printing speed 60 sheets /
Printed in minutes. As the corrugated cardboard sheet, 180 g / m ^{2 of} Jujo Paper White Liner and PALONYA (treated PP) manufactured by Mitsui Toatsu Co., Ltd. were used.

The printed matter thus obtained is output 12
A 0 W / cm metal halide lamp was used to pass the irradiation line at a line speed of 20 m / min and an irradiation distance of 10.8 cm until the ink did not stick to the finger, and the curability was determined. In addition, the evaluation of the viscosity increase was performed by digital incomer (manufactured by Toyo Seiki) 400 rpm circulating water temperature 32.
Rotation was carried out at 0 ° C. for 10 minutes, and the degree of increase was judged by the tack value after 10 minutes and the difference after 1 minute. The printability was judged by whether or not the ink squeezing (adjusting the ink film thickness) between the anilox roller and the counter roller was good.

[0026]

[Table 1]

[0027]

【The invention's effect】

(1) Since the ink is solvent-free, it does not evaporate like the ink produced by the conventional technology and put into practical use, so there is no increase in viscosity on the printing machine and there is no need to constantly circulate the ink. The ink supply system can be simplified.
Moreover, since the evaporation material such as alcohol is not shared, it is possible to prevent the environmental pollution which has become severe these days. (2) Since UV-curable ink is used, printing on water-repellent liner, resin coat liner, film laminar liner, treated plastic corrugated ball is also possible in addition to general liner paper. is there. (3) Since the ink of the present invention is water-soluble, it is possible to use water for cleaning the printing device. (4) The printed surface is instantly dried by irradiating with ultraviolet rays, and the next step is continuously performed, which makes it possible to improve productivity and reduce production cost.

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Claims (3)

(57) [Claims] 1. A main roll forming a fine uneven surface (the anilox roll), and an auxiliary roll arranged opposite to printed on a substrate by contacting the Bando to main roll off
Water-soluble UV-curable ink used for lexographic printing
In G., the water-soluble UV-curable ink contains 5 parts of water-soluble components.
Including 0 to 100% by weight, ink viscosity is 1000 cps
A water-soluble UV-curable ink having a temperature of (25 ° C.) or less and containing neither water nor a water-soluble solvent. Wherein said water soluble ultraviolet curable inks, water-soluble Binney <br/> Le oligomer polymerized and cured by irradiation with ultraviolet rays, water-soluble vinyl monomer, a photopolymerization initiator, a polymerization inhibitor, a pigment main The water-soluble UV-curable ink according to claim 1, which is composed of a mixture of components. 3. The water-soluble UV-curable ink is a viscous ink.
Water-soluble vinyl mono with a degree of less than 150 cps (25 ° C)
Mar of 50-90% by weight.
The water-soluble ultraviolet-curable ink according to item 1.