JPH0741719A - Production of water-base printing ink - Google Patents

Abstract

PURPOSE:To easily produce a water-base printing ink which is excellent in storage stability and forms a coating film excellent in resistances to water, solvents, and alkalis, etc. CONSTITUTION:A water-base printing ink is produced by milling a pigment with a water-dispersible styrene-(meth)acrylic ester-(meth)acrylic acid resin and adding a water-dispersible ethylene-(meth)acrylic acid resin to the resulting mixture.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an aqueous printing ink.

[0002]

2. Description of the Related Art At present, a method for producing a water-based printing ink used in the gravure printing and flexographic printing markets involves dispersing a pigment with a water-soluble resin from the viewpoint of pigment dispersibility, and then adding a water-dispersible resin. In most cases, water-based printing inks are manufactured according to their purpose and use.

However, the water-based printing ink produced in this manner has good printability, but since it uses a water-soluble resin, it has limitations in water resistance, oil resistance, solvent resistance, alkali resistance, etc. There is a defect that these resistances are inferior to the existing oil-based printing inks. On the other hand, in order to improve these drawbacks, there is an example in which a cross-linking agent, for example, a polyfunctional aziridine compound is added to the above-mentioned aqueous printing ink as in JP-A-2-323240. There are problems such as complexity and poor storage stability.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have developed an ink coating having excellent abrasion resistance, water resistance, solvent resistance, alkali resistance, etc. on paper, corrugated board, coated paper, plastic film, polyethylene coated paper and the like. The present invention has been achieved as a result of research on a method for easily forming a water-based printing ink that forms a film and has excellent storage stability.

[0005]

SUMMARY OF THE INVENTION The present invention is a water-dispersible styrene- (meth) acrylic acid alkyl ester- (meth).
The present invention relates to a method for producing a water-based printing ink in which a water-dispersible ethylene- (meth) acrylic acid resin is added after a pigment is dispersed with an acrylic acid resin.

Examples of the water-dispersible styrene- (meth) acrylic acid alkyl ester- (meth) acrylic acid resin which can be used in the present invention include styrene, an alkyl ester of acrylic acid or methacrylic acid, and acrylic acid or methacrylic acid. The thing copolymerized with the acid can be mentioned. Examples of the (meth) acrylic acid alkyl ester include methyl ester, ethyl ester, butyl ester, hydroxyethyl ester, 2-ethylhexyl ester of acrylic acid or methacrylic acid. Use ratio of styrene in resin is 40-70
It is preferable that the use ratio of the (meth) acrylic acid alkyl ester is 20 to 60% by weight, and the use ratio of the (meth) acrylic acid is 2 to 10% by weight. Further, water-dispersible styrene- (meth) acrylic acid alkyl ester-
The molecular weight of the (meth) acrylic acid-based resin is 100,000 to 500,000,
The glass transition point Tg is preferably -5 to 40 ° C and the acid value is preferably 30 to 80. Examples of commercially available water-dispersible styrene- (meth) acrylic acid alkyl ester- (meth) acrylic acid-based resins include John Cryl 74J, John Cryl 7001, John Cryl 741 manufactured by Johnson Polymer Co., Ltd., Luciden manufactured by Morton Thiocole Co., Ltd. 14
1, Luciden 603, Emma Poly DS made by Gifu Shellac
Examples thereof include E70 and Emmapoly DSE334.

The water-dispersible ethylene- (meth) acrylic acid type resin which can be used in the present invention includes those obtained by copolymerizing ethylene with acrylic acid or methacrylic acid. 70% usage
˜95 wt%, and the proportion of acrylic acid or methacrylic acid used is preferably 5 to 30 wt%. The water-dispersible ethylene- (meth) acrylic acid-based resin has a molecular weight of 5,000 to 50,000, a glass transition point of 0 ° C. or lower, and an acid value of 1
It is preferably 0 to 60. Examples of commercially available water-dispersible ethylene- (meth) acrylic acid-based resins include Sumix Seika's Saixen L, Saixen AC, Toho Kagaku Kogyo's Hitec S3121, Hitec S3148 and the like.

The ratio of the water-dispersible styrene- (meth) acrylic acid alkyl ester- (meth) acrylic acid type resin to the water-dispersible ethylene- (meth) acrylic acid type resin is 20: 8.
0 to 80:20 (weight), preferably 40:60 to 6
0:40, and the total amount of the water-dispersible styrene- (meth) acrylic acid alkyl ester- (meth) acrylic acid resin and the water-dispersible ethylene- (meth) acrylic acid resin in the ink is 12 to 30% ( Weight) Use. Water dispersible styrene- (meth) acrylic acid alkyl ester- (meth)
If the acrylic resin is less than 20% of the total resin, the dispersibility of the pigment becomes poor and the color development, density, fluidity, storage stability, etc. become poor. On the other hand, when the water-dispersible styrene- (meth) acrylic acid alkyl ester- (meth) acrylic acid-based resin exceeds 80% of the total resin, there is no problem in pigment dispersibility, but abrasion resistance, water resistance, Solvent resistance, alkali resistance, etc. are reduced, and an excellent ink coating cannot be obtained.

The water-based printing ink according to the present invention further contains a colorant, a solvent, an alkali agent and, if necessary, other auxiliary agents.

As the colorant, it is possible to use inorganic pigments, organic pigments, extender pigments and the like which are used in general water-based printing inks.

As the solvent, water alone or a mixture of water and an organic solvent can be used. As an organic solvent,
For example, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, N-propyl alcohol, isobutyl alcohol, N-butyl alcohol and amino alcohol, glycols such as ethylene glycol and propylene glycol, methyl cellosolve, ethyl cellosolve, butyl cellosolve and propylene glycol. Ethers such as monomethyl ether and propylene glycol monoethyl ether can be used. The proportion of these solvents used is 40.0% to 80.0% by weight in the ink.
It is preferable that The ratio of water to organic solvent is 10
0: 0 to 10:90 (weight), preferably 70:30 to
It is 40:60 (weight).

In the water-dispersible styrene- (meth) acrylic acid alkyl ester- (meth) acrylic acid-based resin and the water-dispersible ethylene- (meth) acrylic acid-based resin, the carboxyl groups are neutralized with an alkaline agent. As the alkaline agent used, for example, ammonia, or morpholine, monoethanolamine, triethanolamine,
Organic amines such as dimethylethanolamine, trimethylamine, triethylamine, aminomethoxypropanol and the like can be mentioned. The alkaline agent is P of the ink
Generally 0.5 so that the H value is 8.0 to 10.0.
It may be used in an amount of 2.0% by weight.

Other auxiliary components include waxes such as paraffin wax, polyethylene wax and carnauba wax for improving abrasion resistance and slipperiness, and oleic acid amide, stearic acid amide, erucic acid amide and the like. Fatty acid amides, silicone-based or non-silicone-based defoaming agents for suppressing foaming or defoaming during printing, and various dispersants for improving wetting of pigments may be appropriately used.

The aqueous printing ink according to the present invention is produced by using a sand mill, a super mill, a bead mill, an attritor, a ball mill or the like which is generally used for producing gravure and flexographic printing inks.

The water-based printing ink according to the present invention is printed on paper, cardboard, plastic film, polyethylene-coated paper, etc. by a printing method in which oil-based printing ink is generally used, that is, gravure printing, flexographic printing, gravure offset printing, etc. be able to.

[0016]

EXAMPLES The present invention will be described below with reference to examples. The numerical values in the examples represent parts by weight.

Example 1 25 parts of Fastgen Blue FGF ^{* 1} , 30 parts of Jonkryl 74J, 1 part of Nopco 8034L ^{* 2} , 22 parts of isopropyl alcohol and 22 parts of water were mixed, and after thoroughly stirring and mixing, This was kneaded with a sand mill to obtain a mill base (A). Using this mill base (A), an aqueous printing ink was produced with the following formulation.

[0018] * 1: Indigo pigment manufactured by Dainippon Ink and Chemicals, Inc. * 2: Defoaming agent manufactured by San Nopco, Inc. * 3: Lubricant manufactured by Mitsui Petrochemical Co., Ltd.

Example 2 Using the same millbase (A) as in Example 1, an aqueous printing ink was prepared with the following formulation.

[0020]

Example 3 25 parts of Shimla Fast Yellow 4400 ^{* 4} , 35 parts of Luciden 141, ⁵ parts of Shamrock S390C ^* 5
Parts, 1 part of Nopco 8034L, 17 parts of industrial ethyl alcohol and 17 parts of water were mixed, thoroughly stirred and mixed, and then kneaded with a beads mill to obtain a mill base (B). Using this mill base (B), an aqueous printing ink was produced with the following composition.

[0022] * 4: Yellow pigment manufactured by Dainippon Ink and Chemicals * 5: Lubricant manufactured by Shamrock Chemical

Example 4 Using the same millbase (B) as in Example 3, an aqueous printing ink was prepared with the following formulation.

[0024]

Comparative Example 1 An aqueous printing ink was prepared by using Jonkryl 74J in place of Hitec S3121 in the formulation of Example 1.

Comparative Example 2 A mill base (C) was produced by using John Cryl 61J ^{* 6} instead of John Cryl 74J in the method for producing a mill base (A) used in Example 1. A water-based printing ink was produced in the same manner as in Example 1 except that the mill base (C) was used instead of the mill base (A). That is, this ink is a water-based printing ink containing a water-soluble acrylic resin instead of the water-dispersible acrylic resin.

* 6: Water-soluble acrylic resin manufactured by Johnson Polymer

Comparative Example 3 Millbase (D) was produced by using Saixen AC instead of Lucidene 141 in the production method of Millbase (B) used in Example 3. A water-based printing ink was produced with the same formulation except that Millbase (D) was used in place of Millbase (B) in the ink formulation of Example 3.

The inks of Examples 1 to 4 and Comparative Examples 1 to 3 were diluted with a mixed solvent of isopropyl alcohol: water = 50: 50 (weight), and the ink viscosity was adjusted to 16 to 17 seconds with a No. 3 Zahn cup. To do. Thickness of each ink is 5
Gravure printing was performed on a treated low-density polyethylene film of 0 μm to obtain each printed matter. For each of these inks, color development, density, fluidity, storage stability, and for each printed material, adhesion, abrasion resistance, water resistance, alcohol resistance,
The coating film performance such as alkali resistance was evaluated. The results are shown in Table 1.
Shown in. The evaluation method and the criteria for the evaluation are as follows.

Color development, density: Visual judgment ○ Good △ Somewhat bad × Bad

Fluidity: No. 4 Zahn cup 25
Viscosity at ℃ (seconds) Criteria ○ 20 seconds or less △ 21-60 seconds × 60 seconds or more

Storage stability: No. 4 Zahn cup after 1 month Viscosity (seconds) at 25 ° C. Judgment standard Same as fluidity

Adhesion: Selling tape 2 manufactured by Nichiban Co., Ltd.
Press 5 mm evenly on the printing surface, and then peel off the cellophane tape quickly from the printing surface. At this time, the state of the ink coating film taken on the cellophane tape is checked.

Judgment criteria ○ No ink peeling × Ink peeling

Friction resistance: Using a Gakushin type fastness friction tester, rubbing with a charcoal under a condition of a load of 200 g and 100 reciprocations, and inspecting for ink peeling. Judgment criteria ○ Good △ Somewhat bad × Bad

Water resistance: The printed matter is immersed in tap water at room temperature (25 ° C.) for 48 hours, then taken out, rubbed with a polyester cloth, and the ink is checked for peeling. Judgment criteria ○ Good △ Somewhat bad × Bad

Alcohol resistance: Using a Gakushin type fastness friction tester, rubbing with a charcoa soaked in ethanol: water = 70: 30 (weight) under the condition of a load of 200 g and 50 reciprocations to remove ink. Find out.

Criteria ○ Good × Bad

Alkali resistance: An aqueous caustic soda solution having a pH of 11 is dropped on the printing surface, and after 5 minutes, rubbing with absorbent cotton is carried out to check the ink for peeling. Judgment criteria ○ Good × Bad

[0040]

[Table 1]

[0041]

EFFECTS OF THE INVENTION According to the present invention, a water-based printing ink which forms a coating film excellent in water resistance, solvent resistance, alkali resistance and the like and has excellent storage stability can be easily produced.

Claims (1)

[Claims] 1. A method of adding a water-dispersible ethylene- (meth) acrylic acid-based resin after kneading a pigment with a water-dispersible styrene- (meth) acrylic acid alkyl ester- (meth) acrylic acid-based resin. A method for producing a characteristic aqueous printing ink.