JP3235687B2 - Aqueous ink composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based ink, and more particularly, to a water-based ink excellent in water resistance and abrasion resistance (durability), particularly a water-based ink composition excellent in jetting stability and suitable for ink jet recording. About things.

[0002]

2. Description of the Related Art Conventional inks for ink jet printers include an oil-based ink in which an oil-soluble dye is dissolved in an organic solvent;
It is classified into an aqueous ink in which a water-soluble dye is dissolved in water. Oil-based inks are excellent in water resistance, but have problems such as safety, odor, and bleeding of printing on plain paper. Therefore, water-based inks are often used for general inkjet recording.

[0003] Colorants used in aqueous inks include:
Although pigments and dyes that can be dispersed or dissolved in water have been generally proposed, the ink jet recording method is a method in which ink is ejected from a fine nozzle of 10 to 200 microns, so there is always a risk of nozzle clogging. Most of the coloring agents used in the above are water-soluble dyes having excellent dissolution stability, among which anionic direct dyes and acid dyes are used. However, these dyes have always conflicting problems of solubility in water and water resistance after recording.

[0004] On the other hand, even when the coloring agent is a pigment, if the binder resin used in the aqueous ink is a dispersion type resin such as an emulsion having water resistance, nozzle clogging is likely to occur. It has the disadvantage of insufficient water resistance and other durability.

[0005] As a method for imparting water resistance to a printed matter by improving an ink composition, (1) JP-A-54-7972 is known.
No. 8 has 6 or less N atoms per molecule,
It includes a polyamine free of primary amine, pH 8 or less alkaline ink composition, (2) JP 55 -1
Japanese Patent No. 20676 discloses an alkaline ink composition containing a polyamine having 7 or more N atoms per molecule, not containing primary nitrogen, and having a pH of 8 or more. Japanese Patent No. 22337 proposes ink jet recording inks containing shellac as a water-soluble dye and a water-soluble anion resin and making the pH of the ink alkaline.

[0006]

However, even with the improvement of the ink composition described above, the reliability, water resistance or durability of the recorded image cannot be said to be sufficient.

An object of the present invention is to provide an aqueous ink composition having excellent reliability such as jetting stability and excellent durability such as water resistance and abrasion resistance of a recorded image. It is to provide a composition.

[0008]

According to the present invention, there is provided an ink jet printer comprising water, a colorant, a water-soluble anionic polymer and a water-soluble cationic polymer. providing recording aqueous ink composition.

In the above aqueous ink composition, it is more preferable that the pH of the ink is 10 or more.

The water-soluble anionic polymer and the water-soluble cationic polymer used in the aqueous ink composition of the present invention are:
Although there is no limitation on the molecular weight, a polymer having a low molecular weight, that is, a polymer having a molecular weight ranging from 3 or more to 10,000 or less is more preferable from the viewpoint of reliability.

Examples of the water-soluble anionic polymer include water of polymers such as polyacrylic acid, shellac, styrene-acrylic acid copolymer, styrene-maleic anhydride copolymer and glycidyl methacrylate-acrylic acid copolymer. There are, but are not limited to, soluble salts.

Examples of the water-soluble cationic polymer include polyamine sulfone, polyvinylamine, polyvinylpyridine, polyethyleneimine, polyethyleneimine-epichlorohydrin reactant, polyamide-polyamine resin,
Examples include, but are not limited to, polyamide-epichlorohydrin resin, cationic starch, or acid neutralized products thereof.

[0013] These water-soluble anionic polymers and water-soluble cationic polymers generally gel at the moment of mixing the two aqueous solutions. However, when the pH of the solution is made alkaline, it starts dissolving, and particularly when the pH is 10 or more. If so, stable solubility can be obtained. However, depending on the combination of the water-soluble anionic polymer and the water-soluble cationic polymer, the pH indicating the dissolution stability is different.
Care must be taken in setting H. Further, since the strength of the obtained ink film is affected by the ratio of the water-soluble anionic polymer to the water-soluble cationic polymer, it is necessary to set an optimum ratio for each resin combination.

Compounds for making the pH highly alkaline include hydroxides of alkali metals such as lithium hydroxide, potassium hydroxide and sodium hydroxide; aqueous ammonia, monoethanolamine, diethanolamine, N-methyl-
Alcohol amines such as diethanolamine; and strong organic base compounds such as morpholine, pyridine, piperidine and derivatives thereof. To significantly increase the water resistance after printing, use volatile basic compounds such as ammonia and organic amines .
Compounds are preferred. These alkaline compounds can also be used for forming a water-soluble salt of the anionic polymer.

Among the colorants of the ink composition used in the aqueous ink composition of the present invention, various organic and inorganic pigments can be used as pigments, and the dyes are various dyes such as anionic dyes, cationic dyes and disperse dyes. Can be used, but anionic dyes are more preferable as colorants from the viewpoint of dissolution stability and reliability, and as the general classification, acid dyes, direct dyes, reactive dyes, disperse dyes, food dyes, and fluorescent brightening It can be appropriately selected from agents and the like.

Specifically, among the anionic dyes, acidic dyes include, for example, C.I. I. Acid Black 1, 2, 7, 16, 17, 24, 26, 28, 31, 4
1, 48, 52, 58, 60, 63, 94, 107, 1
09, 112, 118, 119, 121, 122, 13
1, 155, 156; C.I. I. Acid Yellow 1,
3, 4, 7, 11, 12, 13, 14, 17, 18, 1
9,23,25,29,34,36,38,40,4
1, 42, 44, 49, 53, 55, 59, 61, 7
1, 72, 76, 78, 79, 99, 111, 114,
116, 122, 135, 142, 161, 172;
C. I. Acid Orange 7, 8, 10, 19, 2
0, 24, 28, 33, 41, 45, 51, 56, 6
4; I. Acid Red 1, 4, 6, 8, 13, 1
4, 15, 18, 19, 21, 26, 27, 30, 3,
2, 34, 35, 37, 40, 42, 51, 52, 5
4, 57, 80, 82, 83, 85, 87, 88, 8
9, 92, 94, 97, 106, 108, 110, 11
1, 114, 115, 119, 129, 131, 13
3, 134, 135, 143, 144, 152, 15
4, 155, 172, 176, 180, 184, 18
6,187,249,254,256,289,31
7, 318; I. Acid Violet 7, 1
1, 15, 34, 35, 41, 43, 49, 51, 7
5; I. Acid Blue 1, 7, 9, 15, 2
2, 23, 25, 27, 29, 40, 41, 43, 4
5, 49, 51, 53, 55, 56, 59, 62, 7
8, 80, 81, 83, 90, 92, 93, 102, 1
04, 111, 113, 117, 120, 124, 12
6, 138, 145, 167, 171, 175, 18
3, 229, 234, 236, 249; I. Acid Green 3, 9, 12, 16, 19, 20, 25, 2
7, 41, 44; I. Acid Brown 4, 14
And the like.

Examples of the direct dye include C.I. I. Direct Black 2, 4, 9, 11, 14, 17, 1
9, 22, 27, 32, 36, 38, 41, 48, 4
9, 51, 56, 62, 71, 74, 75, 77, 7
8, 80, 105, 106, 107, 108, 112,
113, 117, 132, 146, 154, 168, 1
71, 194; I. Direct Yellow 1, 2,
4, 8, 11, 12, 24, 26, 27, 28, 33,
34, 39, 41, 42, 44 , 48, 50 , 51, 5
8, 72, 85, 86, 87, 88, 98, 100, 1
10, 127, 135, 141, 142, 144;
I. Direct orange 6, 8, 10, 26, 29,
C. 41, 49, 51, 102; I. Direct Red 1,2,4,8,9,11,13, 15, 17,2
0, 23, 24, 28, 31, 33, 37, 39, 4
4, 46, 47, 48, 51, 59, 62, 63, 7
3, 75, 77, 80, 81, 83, 84, 85, 8
7, 89, 90, 94, 95, 99, 101, 108,
110, 145, 189, 197, 220, 224, 2
25 , 226, 227, 230, 250, 254, 25
6, 257; I. Direct Violet 1, 7,
9, 12, 35, 48, 51, 90, 94; I. Direct Blue 1, 2, 6, 8, 15, 22, 25, 3
4, 69, 70, 71, 72, 75, 76, 78, 8
0, 81, 82, 83, 86, 90, 98, 106, 1
08, 110, 120, 123, 158, 163, 16
5, 192, 193, 194, 195, 196, 19
9, 200, 201, 202, 203, 207, 21
8, 236, 237, 239, 246, 258, 28
7; I. Direct Green 1, 6, 8, 28, 3
3, 37, 63, 64; I. Direct Brown 1
A, 2, 6, 25, 27, 44, 58, 95, 100,
101, 106, 112, 173, 194, 195, 2
09, 210, 211 and the like.

As the reactive dye, for example, C.I. I. Reactive Black 1, 3, 5, 6, 8, 12, 1
4; I. Reactive Yellow 1, 2, 3, 1
3, 14, 15, 17; I. Reactive orange 2, 5, 7, 16, 20, 24; C.I. I. Reactive Red 6, 7, 11, 12, 15, 17, 21, 2
3, 24, 35, 36, 42, 63, 66, 84, 18
4; I. Reactive Violet 2, 4, 5,
8, 9; I. Reactive Blue 2, 5, 7, 1
2, 13, 14, 15, 17, 18, 19, 20, 2
1, 25, 27, 28, 37, 38, 40, 41;
I. Reactive green 5, 7; I. Reactive Brown 1, 7, 16 and the like.

Examples of the food color include C.I. I. Food black 1, 2; I. Food Yellow 2,
4, 5; I. Food red 2,3,7,9,1
4, 52, 87, 92, 94, 102, 104, 10
5, 106; I. Food Violet 2: C.I.
I. Food blue 1, 2; I. Food Green 2, 3 and the like.

On the other hand, examples of basic dyes include C.I.
I. Basic Black 2, 8; C.I. I. Basic
Yellow 1, 2, 11, 12, 14, 21, 32, 3
6; I. Basic Orange 2, 15, 21, 2
2; I. Basic Red 1, 2, 9, 12, 1
3, 37; I. Basic Violet 1, 3,
7, 10, 14; C.I. I. Basic Blue 1, 3,
5, 7, 9, 24, 25, 26, 28, 29; I.
Basic green 1, 4; I. Basic Brown 1, 12 and the like.

Examples of the pigment include inorganic pigments such as carbon black, titanium oxide, zinc white, and zinc sulfide, and organic pigments such as monoazo, disazo, phthalocyanine, and quinacridone, but are not limited thereto. It is not something to be done.

These colorants may be used alone or in combination of two or more. The amount used in the ink composition is 0.1 to 10%.
A range of weight percent is desirable.

In addition, as the ink composition used in the recording method of the present invention, conventionally known water, an anti-drying agent, a penetrant, an antiseptic / antifungal agent and other various ink materials can be used. Is as follows.

The water is preferably of a purity higher than that of ion-exchanged water in order to stabilize the dissolution of the dye and prevent nozzle clogging due to heavy metal ions.

Examples of the water-soluble organic solvent include methyl ether, ethyl ether, isopropyl ether, n-propyl ether, isobutyl ether, n-butyl ether, substituted or unsubstituted phenyl ether, dimethyl ether and diethyl ether of ethylene glycol or propylene glycol. Glycol ethers such as dimethyl sulfoxide; polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol and glycerin; lower alcohols such as ethanol and isopropyl alcohol; pyrrolidone such as N-methyl-2-pyrrolidone And the like. These water-soluble organic solvents can be used alone or in combination of two or more. However, the water-soluble organic solvent that can be used in the present invention is not limited to these.

The amounts of water, water-soluble dye, water-soluble organic solvent and other additives can be appropriately determined in consideration of the required characteristics of the ink and the required physical properties.

[0027]

When a water-soluble anionic polymer and a cationic polymer are combined, a polymer double salt is formed, which is insoluble in water or an organic solvent, and forms a film which is extremely tough and has excellent adhesion. According to the aqueous ink composition of the present invention, for example, unlike the dye insolubilization phenomenon due to the combination of a dye and a polymer having the opposite ionicity in the related art, a result in which the colorant is incorporated into the polymer double salt. , Unprecedented superior water resistance, solvent resistance, and abrasion resistance (durability)
Is obtained.

Further, by making the pH of the ink highly alkaline, ion dissociation of the polymer double salt is promoted to become water-soluble, and after printing, absorption of carbon dioxide in the air and use of a volatile base are further performed. In this case, a tougher film is formed by volatilization of the base.

[0029]

Next, the present invention will be described more specifically with reference to examples and comparative examples.

(Examples 1 to 5 and Comparative Example 1) After mixing each composition shown in Table 1, the mixture was filtered through a 0.5-micron membrane filter to obtain an ink having the viscosity and pH shown in Table 1. Was.

[0031]

[Table 1]

In the table, “John Krill 67” is a styrene acrylic acid copolymer manufactured by Johnson Co., Ltd.
"E" is a polyamide-epichlorohydrin resin manufactured by Dainippon Ink and Chemicals, Inc.

The evaluation was performed as follows.

The stability test was performed using a continuous printer for 100 hours.
The evaluation was made on a scale (○, Δ, ×). After printing on polyethylene terephthalate using a continuous printer, the water resistance was immersed in pure water for one hour, and the state of peeling and discoloration of the ink film was evaluated on a three-point scale (○, Δ, ×). The abrasion resistance was evaluated in three steps (○, Δ, ×) by rubbing the surface with dry gauze after printing.

The results are shown in Table 2.

[0036]

[Table 2]

[0037]

According to the aqueous ink composition of the present invention containing water, a colorant, a water-soluble anionic polymer and a water-soluble cationic polymer, the water resistance and abrasion resistance (durability) of a recorded image are improved. ) Can be improved.

Further, the aqueous ink composition of the present invention having an ink pH of 10 or more exhibits excellent jetting stability.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-60783 (JP, A) JP-A-57-198768 (JP, A) JP-T4-500981 (JP, A) US Patent 4,154,618 (US , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C09D 11/00-11/20

Claims (2)

(57) [Claims] 1. A water, colorants, inkjet recording aqueous ink composition characterized by containing a water-soluble anionic polymer and water-soluble cationic polymer. 2. The ink jet recording aqueous ink composition of claim 1 wherein the pH of the ink is equal to or is 10 or more.