JPH09202868A - Aqueous printing ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous printing ink excellent in ink stability, printing suitability, printing effect and coating physical properties (e.g. adhesivity, water resistance, abrasion resistance, chemical resistance and stain resistance) and suitable for gravure printing by employing a specific resin emulsion as a vehicle. SOLUTION: This aqueous printing ink contains (A) a resin emulsion having a lowest film-forming temperature of 70-230 deg.C (e.g. the emulsion of a resin consisting of a vinyl chloride-vinyl acetate copolymer, a vinyl chloride-acrylate ester copolymer or an acrylate ester polymer) as a vehicle, if necessary, further (B) a phosphate derivative such as trimethyl phosphate and (C) a pigment dispersion. The component A is preferably contained in an amount of 5-95wt.%, preferably 60-85wt.%, in the aqueous printing ink.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an aqueous printing ink suitably used for gravure printing.

[0002]

2. Description of the Related Art In recent years, in the printing field, it has been desired to make printing ink water-soluble due to the problem of volatilization of organic solvents in the atmosphere, resource saving and energy saving, and improvement of working environment and increasing awareness of disaster prevention. Rarely being put to practical use. Vehicles for water-based printing inks have conventionally been shellac, rosin maleic acid-based water-soluble resin, styrene- (meth) acrylic acid copolymer resin, (meth) acrylic acid ester-
A composition in which a (meth) acrylic acid copolymer resin, a urethane resin, a polyester resin, a cellulose derivative or the like is used alone or appropriately blended as necessary is used.

However, these resins have carboxyl groups or amino groups in the resin skeleton in order to dissolve or disperse in water, and the physical properties of coating films of printing inks using these resins as vehicles are alkali, alcohol, etc. Extremely insufficient chemical resistance. On the other hand, there have been studies on inks that use emulsion type resins for vehicles, but the physical properties of the coating film can be improved, but the ink dispersibility, re-dissolution property, ink suitability for printing such as poor plate fog property, and printability are improved. It is not used because it has a problem in terms. Therefore, in the field where chemical resistance is required, a two-component aqueous printing ink using an organic solvent type ink or a cross-linking agent is used. There is a problem of workability such as plate clogging due to the pot life of the printing ink later, and a problem of economy due to poor temporal stability of the compounded ink.

[0004]

The first object of the present invention is to obtain a water-based printing ink having excellent ink stability, printing effect and printability, and the second object is the physical properties of coating film (adhesion). Properties, water resistance, abrasion resistance, chemical resistance, stain resistance, etc.)
To obtain a water-based printing ink having

[0005]

That is, the present invention provides a water-based printing ink characterized in that a resin emulsion having a minimum film-forming temperature of 70 to 230 ° C. is used as a vehicle. Further, in the present invention, the resin emulsion is a vinyl chloride-vinyl acetate copolymer, a vinyl chloride-acrylate copolymer and an acrylate polymer selected from the group consisting of one or two or more. The water-based printing ink is provided as an emulsion of a resin. Furthermore, the present invention provides the above water-based printing ink, which comprises a phosphoric acid derivative. Further, the present invention provides the above aqueous printing ink, which comprises a pigment dispersion.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The minimum film forming temperature (hereinafter referred to as MFT) of a resin emulsion used as a vehicle for an aqueous printing ink of the present invention is 70 to 230 ° C., preferably 1
It is in the range of 00 to 210 ° C. In the present invention,
MFT means the minimum temperature at which emulsion particles can be adhered to each other and fused to form a continuous film, as described in JIS K 6828 (Vinyl acetate resin emulsion test method). If the MFT is less than 70 ° C., the printability such as ink re-dissolvability and washability will be insufficient. If it exceeds 230 ° C, the drying temperature during printing of the aqueous printing ink is about 70 to 150 ° C, and the heating condition during the post-processing of the printed matter is about 180 to 230 ° C, so that no ink film is formed. The printability such as drying property becomes insufficient.

As the resin emulsion, vinyl chloride resin emulsion, vinyl acetate resin emulsion, vinyl chloride-vinyl acetate copolymer emulsion, acrylic ester polymer emulsion, vinyl chloride-acrylic ester copolymer emulsion. , Vinyl acetate-acrylic ester copolymer emulsion, ethylene-
Vinyl acetate copolymer emulsion, vinyl acetate-ethylene-vinyl chloride copolymer emulsion, vinyl chloride-vinylidene chloride copolymer emulsion, styrene
Examples thereof include a butadiene copolymer emulsion, a butadiene-acrylonitrile copolymer emulsion, a urethane resin emulsion, a fluorine resin emulsion, an epoxy resin emulsion, and a polyester resin emulsion.

Among them, an emulsion of one or more resins selected from the group consisting of vinyl chloride-vinyl acetate copolymers, vinyl chloride-acrylic acid ester copolymers and acrylic acid ester polymers is obtained. It is preferably used. The resin emulsion having an MFT of 70 to 230 ° C. is 5 to 95% by weight in the aqueous printing ink, and further 60
It is preferably used in the range of ~ 85% by weight. When the amount of the resin emulsion used is less than 5% by weight, various properties such as printability and ink adhesion and chemical resistance are insufficient, and when it exceeds 95% by weight, ink stability, etc.
Inkability becomes insufficient.

The water-based printing ink of the present invention has an MFT of 70.
~ 230 ° C resin emulsion, colorant, phosphoric acid derivative if necessary, water, water-soluble organic solvent, various additives, etc. are mixed and dispersed and mixed by a known disperser, mixer, kneader, etc. It is manufactured by kneading. Examples of the colorant include phthalocyanine pigments, soluble azo pigments, insoluble azo pigments, naphthol pigments, isoindolinone pigments, organic oxides such as titanium oxide, carbon black, calcium carbonate, and precipitated barium, and extender pigments. In order to obtain sufficient color development as an ink, it is preferable to use a pigment dispersion (conc base) obtained by dispersing the above pigment in water at a high concentration of 30 to 75% by weight using a surfactant.

The phosphoric acid derivative is used in an amount of 1 to 5% by weight in the aqueous printing ink in order to improve printability such as plate fog.
It can be preferably used in the range of 1 to 3% by weight.
If the amount of the phosphoric acid derivative is too small, the printing suitability such as plate fogging becomes insufficient, and if it is too large, the ink forming suitability such as ink stability becomes insufficient. Examples of the phosphoric acid derivative include trimethyl phosphate (TMP), triethyl phosphate (TEP), tributyl phosphate (TBP), tri- (2-ethylhexyl) phosphate (TOP), tributoxyethyl phosphate (TB).
XP).

As the water-soluble organic solvent, methyl alcohol, ethyl alcohol, isopropyl alcohol, N
Alcohols such as propyl alcohol; glycols such as ethylene glycol and propylene glycol; and glycol ethers such as butyl cellosolve, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether. The weight ratio of water to the water-soluble organic solvent is 100
In the case of alcohols, 100/0 to 98/2 is preferable from the viewpoint of disaster prevention.

In the water-based printing ink of the present invention, in addition to the above-mentioned constituent materials, if necessary, bases such as ammonia, triethylamine, aminomethylpropanol, monoethanolamine, diethylaminoethanol, sodium hydroxide, potassium hydroxide, etc. Fine powder silica such as vapor phase silica, wet silica, organic treated silica, alumina treated silica, polyethylene wax, defoaming agent, leveling agent,
A tackifier, a preservative, a fungicide, an antibacterial agent, a rust inhibitor and the like can be added.

[0013]

The present invention will be described in detail below with reference to examples. In addition, part and% in an Example represent a weight part and weight%, respectively. [Example 1] (1) Acrylic ester polymer emulsion 68.0 parts (minimum film forming temperature 77 ° C, solid content 34%) (2) Polyethylene wax 3.0 parts (3) Water 3.9 parts (4) Silicone antifoaming agent 0.1 part (5) TBXP 2.0 part (6) Urethane-modified polyether tackifier 3.0 part (7) Phthalocyanine pigment dispersion (pigment content 42.5% ) 20.0 parts (1) to (6) in the above composition are mixed with a stirrer, dispersed with a tabletop sand mill, and (7) is mixed with a stirrer to prepare an aqueous printing ink having a particle size of 30 μm with a grind gauge. Obtained.

Example 2 (1) Vinyl chloride-vinyl acetate copolymer emulsion 75.9 parts (minimum film forming temperature 130 ° C., solid content 55%, vinyl chloride / vinyl acetate ratio = 50/50) (2) Polyethylene wax 3.0 parts (3) Water 7.0 parts (4) Silicone defoamer 0.1 part (5) TOP 3.0 parts (6) Urethane-modified polyether tackifier 3 0.0 parts (7) Condensed azo pigment 8.0 parts The above compositions (1) to (7) were mixed with a stirrer and dispersed with a tabletop sand mill to obtain an aqueous printing ink having a particle size of 30 μm with a grind gauge.

Example 3 An aqueous printing ink having the following composition was obtained in the same manner as in Example 1. (1) Vinyl chloride-acrylic acid ester copolymer emulsion 73.9 parts (minimum film forming temperature 210 ° C., solid content 43%, vinyl chloride / acrylic acid ester ratio = 90/10) (2) polyethylene wax 3 0.0 parts (3) Water 4.0 parts (4) Silicone antifoaming agent 0.1 parts (5) TBP 1.0 part (6) Urethane modified polyether tackifier 3.0 parts (7) Carbon black dispersion (pigment content 40.5%) 15.0 parts

[Example 4] (1) Acrylic ester polymer emulsion 69.5 parts (minimum film forming temperature 77 ° C, solid content 34%) (2) Polyethylene wax 3.0 parts (3) Water 4 4 parts (4) Silicone-based defoaming agent 0.1 part (5) Urethane-modified polyether-based tackifier 3.0 part (6) Phthalocyanine pigment dispersion (pigment content 42.5%) 20.0 parts After mixing (1) to (5) in the above composition with a stirrer, they were dispersed with a desktop sand mill, and (6) was mixed with a stirrer to obtain an aqueous printing ink having a particle size of 30 μm with a grind gauge.

Comparative Example 1 In the same manner as in Example 1, an aqueous printing ink having the following composition was obtained. (1) Vinyl acetate-ethylene-vinyl chloride copolymer 69.0 parts Emulsion (minimum film forming temperature 40 ° C, solid content 50%, vinyl acetate / ethylene / vinyl chloride ratio = 30/20/50) (2 ) Polyethylene wax 3.0 parts (3) Water 3.9 parts (4) Silicone-based defoamer 0.1 part (5) TBXP 1.0 part (6) Urethane-modified polyether-based tackifier 3.0 Parts (7) Phthalocyanine pigment dispersion (pigment content 42.5%) 20.0 parts

Comparative Example 2 In the same manner as in Example 1, an aqueous printing ink having the following composition was obtained. (1) Vinyl chloride-vinyl acetate copolymer emulsion 71.0 parts (minimum film forming temperature 50 ° C., solid content 43%, vinyl chloride / vinyl acetate ratio = 50/50) (2) polyethylene wax 3.0 Parts (3) water 13.9 parts (4) silicone defoamer 0.1 parts (5) TBP 1.0 part (6) urethane modified polyether tackifier 3.0 parts (7) phthalocyanine pigment 8.0 copies

Comparative Example 3 In the same manner as in Example 4, an aqueous printing ink having the following composition was obtained. (1) Acrylic ester type polymer emulsion 67.0 parts (minimum film forming temperature 23 ° C., solid content 42%) (2) Polyethylene wax 3.0 parts (3) Water 6.9 parts (4) Silicone type Defoaming agent 0.1 part (5) Urethane-modified polyether-based tackifier 3.0 part (6) Pigment dispersion (phthalocyanine pigment, pigment content 42.5%) 20.0 parts

The water-based printing inks obtained in Examples and Comparative Examples were evaluated for printability (resolubility, plate washability, plate fogability). Further, the aqueous printing inks obtained in Examples and Comparative Examples were diluted with water in Zahn cup # 3-25 seconds, and the foamed vinyl chloride sol coat-containing PVC wallpaper raw material was
After performing gravure printing using a heliocrission 175 lines / inch plate, the printed matter is heated and foamed in a hot air oven at 220 ° C. for 45 seconds, and the physical properties of the coated film after heat foaming (adhesion, water resistance, friction resistance) Properties and chemical resistance) were evaluated.
The results are shown in Table 1. In addition, the judgment on printability is △ ~
○ indicates that the physical properties of the coating film are judged as ○. The evaluation method and criteria are as follows.

Re-dissolvability: Printing is started to obtain a printed matter. Next, the printing press is stopped, and after 15 minutes, the printing press is operated again to obtain a printed product. The printed matter after the restart is compared with the original printed matter, and the reproducibility of the image is visually determined. Judgment criteria ○ Good △ Slightly poor × Poor plate washability: The gravure plate stopped for 15 minutes by the resolubility evaluation method is washed with water, and the degree of dropping of ink adhering to the plate is determined. Judgment criteria ○ Good △ Slightly poor × Bad Plate fogging property: First printed at 70 m / min for 1 minute,
The plate was then allowed to idle for 30 minutes without printing. Thereafter, printing was performed again for one minute, and the degree of background contamination on the plain portion of the printing medium was visually determined. Judgment criteria ○ No plate fog at all △ Flat plate fog × Normal plate fog

Adhesiveness: A 25 mm width of cellophane tape is pressed uniformly on the printing surface, and then the cellophane tape is peeled off from the printing surface quickly. At this time, the state of the ink coating film taken on the cellophane tape was determined. Judgment criteria ○ No ink peeling △ Slight ink peeling × Notable ink peeling Water resistance: Using a Gakushin type fastness friction tester, load 20
Under the condition of 0 g and 100 reciprocations, friction was determined with a wet cotton cloth, and a determination was made based on the elution state of the ink. Judgment criteria ○ Good △ Slightly poor × Poor Friction resistance: Under the same conditions as in the evaluation of water resistance, the state of ink rubbing against fine paper is judged. Judgment criteria ○ Good △ Somewhat bad × Bad

Chemical resistance (acid, alkali, alcohol, household detergent): Judgment is made by the elution state of ink after leaving absorbent cotton containing 5% hydrochloric acid aqueous solution and 5% caustic soda aqueous solution on the printed matter for 1 hour. In addition, the elution state of the ink is determined by rubbing 100 times with absorbent cotton containing special grade ethanol. In addition, commercially available household detergents (“Sun Pole” manufactured by Dainippon Insects and Pests Ltd., “Mama Lemon” manufactured by Lion Corporation, “Kitchen Highter” manufactured by Kao Corporation, and “My Pet”) were left undiluted on the printed matter for 1 hour. Is determined based on the state of contamination on the printed matter. In Table 1,
The results of the comprehensive evaluation are shown. Judgment criteria ○ All good △ Some defective × All defective

[0024]

[Table 1]

[0025]

According to the present invention, excellent ink stability, printability, printing effect, and physical properties of coating film (adhesion, water resistance,
An aqueous printing ink having rub resistance, chemical resistance, stain resistance, etc.) can be obtained, and its industrial value is enormous.

Claims (4)

[Claims] 1. A water-based printing ink comprising a resin emulsion having a minimum film-forming temperature of 70 to 230 ° C. as a vehicle. 2. The resin emulsion, wherein the resin emulsion is one or more resins selected from the group consisting of vinyl chloride-vinyl acetate copolymers, vinyl chloride-acrylate copolymers and acrylate polymers. 2. The aqueous printing ink according to claim 1, which is an emulsion of the formula (1). 3. The aqueous printing ink according to claim 1, which contains a phosphoric acid derivative. 4. The aqueous printing ink according to claim 1, further comprising a pigment dispersion.