JPH04117469A - Ink for printing corrugated cardboard and method for printing corrugated cardboard therewith - Google Patents

Abstract

PURPOSE:To decrease drying and curing time and improve gloss and abrasion resistance by compounding a water-sol. ultraviolet-curable resin, water, a water- sol. solvent, and a pigment. CONSTITUTION:10-40wt.% water-sol. ultraviolet-curable resin, pref. a monomer or oligomer of an epoxy acrylate or a urethane acrylate contg. an amine salt of a carboxyl group and an alkali metal salt of sulfonic acid group, 1-25wt.% water, 10-40wt.% water-sol. solvent, pref. isopropyl alcohol or N-vinylpyrrolidone, 10-25wt.% pigment, and if necessary a water-sol. monomer and a photopolymn. initiator are compounded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a printing ink for cardboard and a method of printing cardboard using the same.

(Prior Art) Conventionally, there are the following methods for printing on cardboard.

(a) Flexo method that uses water-based ink (b) Pre-throttle method that uses water-soluble ink that mainly uses glycol-based solvents and water However, these methods have problems such as insufficient gloss and slow drying. Ta.

(Problems to be Solved by the Invention) The present inventors have conducted extensive research to solve future problems, and as a result, have arrived at the present invention.

(Means for Solving the Problems) The present invention provides a printing ink for cardboard, which is characterized by containing a water-soluble ultraviolet curable resin, water, and a water-soluble solvent, and a water-soluble ultraviolet curable resin. The present invention relates to a method for printing corrugated board, characterized in that printing is performed on corrugated board using a printing ink containing a water-soluble solvent and a water-soluble solvent.

The printing ink for cardboard according to the present invention is characterized in that it contains a water-soluble ultraviolet curable resin, water, and a water-soluble solvent.

The water-soluble ultraviolet curable resin gives high gloss and high abrasion resistance to the printing ink film for corrugated board, and because it cures instantly, it can be transferred to post-processing processes such as slitting and pasting without any problems, making it suitable for in-line processing systems. It opens the way. Water and water-soluble solvents are effective in reducing costs and making a smooth transition from glycol-based inks and water-based flexographic inks.

As water-soluble UV-curable resins, monomer oligomers of epoxy acrylates and urethane acrylates having hydroxyl groups, carboxyl groups, amine salts of carboxyl groups, ammonium salts of carboxyl groups, and alkali metal salts of sulfonic acid groups in side chains or terminals are used. Although possible, from the viewpoint of water solubility, those containing an amine salt of a carboxyl group or an alkali metal salt of a sulfonic acid group are preferable. To adjust the viscosity of the ink, PO-modified trimethylolpropane triacrylate and acrylic-modified alkyd resin can be used together. The proportion of water-soluble ultraviolet curable resin used is
It is preferable to make it 10 to 40% by weight in the printing ink for corrugated board.

Preferably, water is used in an amount of 1 to 25% by weight in the printing ink for corrugated board.

As water-soluble solvents, methanol, ethanol, isopropyl alcohol, n-flobil alcohol, isobutanol, n-butanol, N-vinylpyrrolidone, methyl cellosolve, ethyl cellosolve, etc. can be used, but from the point of view of economy and ink film quality, isopropyl The alcohol N-bivinibirrolidone is preferred. The proportion of the water-soluble solvent used in the printing ink for cardboard is preferably 10 to 40% by weight.

It is preferable to use a water-soluble monomer in the printing ink for cardboard according to the present invention, and examples of the water-soluble monomer include Aloe 1. manufactured by Toagosei Kagaku Co., Ltd. Kusu M-240, Aronix M-260, Photomer 415 manufactured by Jamrock Co., Ltd.
8. New Frontier PE-400 manufactured by Daiichi Kogyo Co., Ltd. can be used, and the usage rate is 30% in the printing ink for cardboard.
It is preferable to set the amount to 60% by weight.

It is preferable to use a photopolymerization initiator in the printing ink for corrugated board according to the present invention, and examples of the photopolymerization initiator include Daitocure OB manufactured by Daito Kagaku Co., Ltd. and Darokinia 2959 manufactured by Merck & Co., Ltd.; The proportion used is preferably 5 to 10% by weight in the printing ink for cardboard.

As the pigment that is the other constituent material, ordinary pigments for water-based inks can be used, such as monoazo-based, disazo-based, quinacridone-based, dioxazine-based, naphthol-based,
Organic pigments such as phthalocyanine, inorganic pigments such as titanium dioxide and barium sulfate, and carbon black can be used. The proportion of pigment used in the printing ink for corrugated board is preferably 10 to 25% by weight.

As a method for printing on corrugated board according to the present invention, a method may be adopted in which after printing on liner paper such as K liner, Geniet liner, white liner, etc., a method of applying A-stage processing or 8-stage processing to form corrugated board, Alternatively, a method of directly printing on cardboard may be adopted, or if necessary, the surface may be subjected to a water-repellent treatment and then printed on liner paper or cardboard.

Printing machines can be broadly divided into flexographic printing machines that print on liner paper and pre-throttle printing machines that print on cardboard, and the present invention can be applied to either of them.

Both of these printing machines are mainly equipped with letterpress (flexographic) printing presses for clothing, but in special cases, intaglio printing (gravure printing) may be used for background patterns, preprints, etc. This printing method can be applied to any type of clothes.

Letterpress materials and roll materials are commercially available for UV and UV.
/ Conventional type can be used without any problems.

The printing press according to the present invention only needs to be equipped with an ultraviolet irradiation device between the cylinders or after the unit, and can be used depending on the pattern configuration, similar to the UV printing currently practiced.

(Example) Examples 1 to 3 and Comparative Example 1 and Comparative Example 2 In the following, all parts and percentages are based on weight unless otherwise specified. 295 parts of sodium dimethylsulfoisophthalate and 3-methyl-1,5-
590 parts of bentanediol, [Fascat 410
A transesterification reaction was carried out by adding 16 parts of N (organotin catalyst manufactured by M&T Corporation, USA) to convert 2 moles of 3-methyl-1,5- into 1 mole of sodium dimethylsulfoisophthalate. A mixture of a diol having a sodium sulfonate base in the molecule obtained by reacting bentanediol with 3-methyl-1,5-bentanediol was obtained.

Next, 292 parts of adipic acid was added to 821 parts of this mixture, and an esterification reaction was carried out to perform a polyester diol (a-1-1
) was obtained.

After that, this polyester diol (a-1-1)
3123 parts, 348 parts of tolylene diisocyanate, 2
,6-tert-butyl-4-methylphenol 1
2.2 parts and 0 hydroquinone monomethyl ether
．． 82 parts of di-n-butyltin diacetate)
Add 0.82 parts and carry out the urethanization reaction at 80°C,
Sodium sulfonate base-containing polyurethane diol (
a-1-2) was obtained.

Separately, 1 mole of tolylene diisocyanate and 1 mole of 2-hydroxy engineered acrylate were subjected to a urethane reaction in a conventional manner to obtain an unsaturated urethane compound.

Next, 580 parts of this unsaturated urethane compound was added to 3471 parts of the previously obtained sodium sulfonate base-containing polyurethane diol (a-1-2), and a urethane reaction was carried out at 80°C to obtain a water-soluble ultraviolet curable resin. Ta. The obtained water-soluble ultraviolet curable resin is referred to as Resin A.

To 3471 parts of the sodium sulfonate base-containing polyurethane diol (a-1-2) obtained in the resin A production step,
952 parts of an unsaturated urethane compound obtained by reacting tolylene diisocyanate 17 with 1 mole of ruthhentaerythritol triacrylate was subjected to a urethanization reaction at 80°C to obtain a water-soluble ultraviolet curable resin. The obtained water-soluble ultraviolet curable resin is referred to as resin B.

Similarly, the sodium sulfonate base-containing polyurethane diol (a-1-2) obtained in the resin A production step 89
410 parts of an unsaturated urethane compound obtained by reacting 1 mole of tolylene diisocyanate with 1 mole of pentaerythritol triacrylate was reacted with 0 part to urethane at 80°C to obtain a water-soluble ultraviolet curable resin. The obtained ultraviolet curable water-soluble resin is referred to as Resin C.

Phthalocyanine Blue TGR-L (manufactured by Dainippon Ink & Chemicals Co., Ltd.) Resin A Aronix M-260 (manufactured by Toagosei Kagaku Co., Ltd.) Photomer 4158 (manufactured by Jamrock Co., Ltd.) Daito Gyu Ni-0B (manufactured by Daito Kagaku Co., Ltd.) Sasol Wax 5PN -3 (manufactured by Sasolchem Co., Ltd.) Total: 15 parts 50 parts 15 parts 15 parts 4 parts 1 part 00 parts The above formulation was kneaded with three rolls to prepare base ink A.

Base ink B was prepared by changing resin A to resin B and kneading it in the same manner using three rolls.

Base ink C was prepared by changing resin A to resin C and kneading it in the same manner using three rolls.

Add 10 parts of water and 30 parts of isopropyl alcohol to 60 parts of each base ink AS B and C, and stir thoroughly with a disper stirrer to prepare printing ink A for corrugated poles as Example 1, printing ink B for corrugated boards as Example 2, and Example 2. As Example 3, printing ink C for cardboard was produced.

When printing ink A for cardboard, printing ink B for cardboard, and printing ink for cardboard C were spread on K liner paper at 6 g/m2 using an R1 printing aptitude tester (manufactured by Mei Seisakusho), sufficient transferability was obtained. It was done.

In addition, when printing was performed on white liner paper at a speed of 60 m/min using a TM pear-shaped two-color labia rotary press (manufactured by Jyo Tekko Co., Ltd.) using Ami-gravure plate 175 line 25μ, clear printed matter was obtained.

In addition, when printing was performed on jute liner paper using a rubber flexographic plate using a flexographic printing suitability tester (manufactured by Mei Seisakusho), good printed matter was obtained.

Next, printing ink for cardboard A1, printing ink for cardboard B2, printing ink for cardboard C was spread at 6 g/m2 on white liner paper using an R1 printing aptitude tester, and the printing ink was applied at 160 W/cm.
Metal halide ultraviolet lamp (manufactured by Nippon Battery Co., Ltd.) 1
When irradiated at a speed of 50 m/min from a distance of 10 cm, all were sufficiently cured.

When the gloss and abrasion resistance of the obtained cured colored product were measured, the results shown in Table 1 were obtained.

As Comparative Example 1, a commercially available glycol-type ink was developed in the same manner as printing ink A for cardboard.
60%) for 30 minutes.

When the gloss and abrasion resistance of the dried colored product obtained were measured, the results shown in Table 1 were obtained.

As Comparative Example 2, a commercially available water-based flexographic ink was applied to white liner paper using anilox hand blue fur at 6 g/m.
15 at room temperature (25°C 60%)
Dried in seconds. When the gloss and abrasion resistance of the dried colored product obtained were measured, the results shown in Table 1 were obtained.

Table 1 * Gloss Digital glossy needle (manufactured by Nippon Denshoku Industries Co., Ltd.) 6
0°/60° *Abrasion resistance Gakushin type fastness tester (manufactured by Daiei Seiki Seisakusho)
Number of frictions until ink film scratches/load 500
g As is clear from Table 1, according to the present invention, an ink film with excellent gloss and abrasion resistance can be formed.

(Effects of the Invention) According to the present invention, an ink film with excellent gloss and abrasion resistance can be formed in an extremely short drying and curing time.

Claims (1)

[Scope of Claims] 1. A printing ink for cardboard, characterized by containing a water-soluble ultraviolet curable resin, water, and a water-soluble solvent. 2. A method for printing cardboard, which comprises printing on cardboard using a printing ink containing a water-soluble ultraviolet curable resin, water, and a water-soluble solvent.