JPH04359071A - Ink composition for aqueous recording - Google Patents

Abstract

PURPOSE:To obtain an ink composition for aqueous recording containing a pigment and a specific acetylene glycol and being excellent in storage stability (e.g. abrasion resistance or water resistance) and discharge stability in recorded and printed article. CONSTITUTION:An ink composition for aqueous recording containing at least one (A) pigment such as toluidine red and (B) acetylene glycol expressed by the formula (R1 to R4 are 1-6C alkyl; m and n are integer of >=1) and used for ink jet printer. Further, the above component B is contained preferably in an amount of 0.01-10wt.% based on total weight of ink, and the ink composition for aqueous recording has a surface tension at 20 deg.C of preferably in the range of 20-40dyn/cm.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous recording ink composition for use in an inkjet printer that performs recording using liquid ink.

0002

BACKGROUND OF THE INVENTION Conventionally, examples of using acetylene glycols as additives in aqueous recording ink compositions have been described in Japanese Patent Publication No. 58-6752, Japanese Patent Application Laid-Open No. 63-139964, and the like.

0003

[Problems to be Solved by the Invention] Acetylene glycols have traditionally been used as wettability improving agents, and when liquid ink containing them is used to record on plain paper, it quickly penetrates into the recording paper. Although it has excellent ink drying properties, it is susceptible to water, organic solvents, etc. even after the ink dries, and water droplets easily cause the ink to run on the recording paper, resulting in deterioration of print quality and, in severe cases, loss of characters, etc. disappear,
Improving its water resistance and solvent resistance has been a major challenge.

[0004] Also, by using pigments as colorants,
Although high light resistance, chemical resistance, and water resistance can be imparted to the recorded material, the abrasion resistance is weaker than ink that uses dye as the colorant, and pigments are added to the recording paper to prevent printed matter from staining. It needed to be established. When a fixing component is added to an ink, water-soluble polymers are usually used as the fixing component, which causes problems such as an increase in ink viscosity and deterioration of ejection stability such as solidification near the ejection nozzle.

[0005]The present invention is intended to solve these problems, and one of its objects is to provide a new aqueous recording ink composition.

Another object of the present invention is that the pigment has
An object of the present invention is to provide an aqueous recording ink composition that takes advantage of high light resistance, chemical resistance, and water resistance, and also has abrasion resistance, and has storage stability of recorded materials as high as that of an electrophotographic method.

[0007]

[Means for Solving the Problems] The aqueous recording ink composition of the present invention is characterized in that it contains at least a pigment and one or more acetylene glycols represented by the following general formula.

[0008]

[Case 2]

(However, R1 to R4 are linear or branched alkyl groups having 1 to 6 carbon atoms, and m and n are integers of 1 or more.) Also, the acetylene glycol is added to 0% of the total weight of the ink. It is characterized by containing .01 to 10% by weight, and has a surface tension of 25 dyn/cm at 20°C.
It is characterized by being in the range of ~40 dyn/cm.

(Specific Description of the Invention) The materials used in the aqueous recording ink composition of the present invention will be explained in detail below.

Conventionally, water has been mainly used as a solvent for ink compositions due to its low viscosity, excellent safety, ease of handling, low cost, and lack of odor. It is being In addition, for the purpose of improving various properties, water-soluble organic solvents such as alcohols such as ethanol and propanol, polyhydric alcohols such as ethylene glycol, diethylene glycol, and glycerin, or etherified and esterified products thereof can be added. .

Among the colorants, carbon black can be either acidic carbon black or basic carbon black. Acidic carbon black has a hydrophilic functional group such as a hydroxyl group, a carboxyl group, or a sulfone group on its surface, or has a large coating layer of a substance having a hydrophilic functional group, and has a pH of 6 or less. The pH of this carbon black refers to a value obtained by the following measuring method. That is, put 3 g of carbon black to be measured and 100 g of distilled water into a beaker, measure the total weight,
Boil this for 1 hour. After cooling to room temperature, the total weight is measured, and after adding distilled water that has been reduced by boiling and stirring, the mixture is allowed to stand for 10 minutes, and the pH of the supernatant liquid is measured using a glass electrode pH meter.

[0013] Commercially available carbon blacks having a pH of 6 or less according to the above measurement method are, for example, Mitsubishi Chemical Industries, Ltd. registered trademarks #2400B, #2350, #2200B, #100.
0, MA100, MA7, MA8, MA11, Degussa registered trademark Special Black 550, Special Black 350, Special Black 250, Special Black 100, Columbian Carbon registered trademark Raven 1255, Raven 1200, Raven 1170, Raven 1060, Raven 1040 , Raven 1030,
Cabot registered trademark Monarch 1300, Mogul L,
Regal 400, Vulcan XC-72, etc. can be used, but the carbon black of the present invention with a pH of 6 or less,
It is not limited to the above-mentioned commercially available products, but it is also possible to use products that have been treated with various oxidizing agents and surface modification methods such as plasma treatment to have a pH of 6 or less.

[0014] The pH of basic carbon black is also measured in the same manner as acidic carbon black, and its structure is characterized by the fact that it has an amine functional group on its surface or is coated with a substance that has an amine functional group. It has many layers and has a pH of 7 or more. Specifically, commercially available carbon blacks having a pH of 7 or more are, for example, Mitsubishi Chemical Industries, Ltd. registered trademarks #2300, #900, #950, #850,
MCF88, CF9, #4000B, #52, #44,
#40, #5B, Degussa registered trademark Printex 95
, Printex 90, Printex 85, Printex 80, Printex 75, Printex 55
, Printex 45, Printex 40, Printex P, Columbian Carbon Co., Ltd. registered trademark Raven 7
90, Raven 450, Raven 430, Raven 42
0, Raven 410, Raven H20, Cabot registered trademark Monarch 880, Monarch 800, Monarch 70
0, Regal 330R, Elftex 8, Elftex 12, Lion Akzo registered trademark Ketjen Black EC, Ketjen Black EC-DJ500, Ketjen Black EC-DJ600, etc. can be used. Further, like the acidic carbon black, the carbon black with a pH of 7 or higher according to the present invention is not limited to the above-mentioned commercially available carbon blacks, but it is also possible to use carbon blacks that have been treated with various treatment agents and surface modification methods to have a pH of 7 or higher. . The amount of carbon black added is 0.5 to 3 based on the total weight of the ink composition.
It is preferably 0% by weight, and more preferably 3 to 12% by weight. Organic pigments that can be used in the present invention are not particularly limited, and include toluidine red, permanent carmine FB, fast yellow AAA, and disazo orange PMP.
, Lake Red C, Brilliant Carmine 6B, Phthalocyanine Blue, Quinacridone Red, Dioxane Violet, Pictoria Pure Blue, Alkaline Blue Toner, Orthonitroaniline Black, and other organic pigments can be used. In order to improve the wettability of these pigments, they may be subjected to surface treatment. The amount added is 1 to 30% by weight.
is preferable, and more specifically, 3 to 10% by weight is preferable. Furthermore, it can be used in combination with conventionally used coloring agents such as direct dyes, acid dyes, food dyes, basic dyes, reactive dyes, and disperse dyes.

The dispersant that can be used in the present invention is a conventional water-soluble surfactant or a polymeric dispersant. As the water-soluble surfactant, ordinary water-soluble ionic or nonionic surfactants can be added. For example, anionic surfactants include higher fatty acid salts, higher alkyl dicarboxylate salts, higher alcohol sulfate salts,
Higher alkyl sulfonates, condensates of higher fatty acids and amino acids, sulfosuccinic acid ester salts, naphthenates, etc. can be used. Next, as cationic surfactants, aliphatic amine salts, quaternary ammonium salts, sulfonium salts,
Examples of amphoteric surfactants such as phosphonium salts include betaine types, and nonionic surfactants include fatty acid ester types of polyoxyethylene compounds, polyethylene oxide condensation types, etc., or one or more types thereof can be used. As the nonionic surfactant, fatty acid esters of polyoxy compounds, polyethylene oxide condensates, and the like can be used. The amount added can be appropriately set depending on the type. The amount of the dispersant added to the total weight of the ink composition is preferably 0.01 to 5% by weight.

The following polymeric dispersants are expected to act as a protective colloid layer for pigment particles, and are preferably added to an extent that does not impede ejection stability such as clogging. Specifically, proteins such as gelatin and casein, natural gums such as gum arabic, glucoxides such as sabonin, cellulose derivatives such as methylcellulose, carboxymethylcellulose, and hydroxymethylcellulose, lignin sulfonates, natural polymers such as shellac, and polyacrylics. acid salt, styrene-acrylic acid copolymer salt, vinylnaphthalene-acrylic acid copolymer salt, styrene-maleic acid copolymer salt, vinylnaphthalene-maleic acid copolymer salt,
Sodium salt of β-naphthalene sulfonic acid formalin condensate, anionic polymers such as polyphosphoric acid, nonionic polymers such as polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, and one or more of these. can be used in combination. The amount of the polymeric dispersant added is 0.3 to 2% based on the total weight of the ink composition.
% by weight is preferred, more preferably 0.5-1% by weight
It is.

In addition to the above, alkanolamines such as triethanolamine may be added as a pH adjuster if necessary. Furthermore, benzoic acid, dichlorophene, hexachlorophene, sorbic acid, p-hydroxybenzoic acid ester, ethylenediaminetetraacetic acid (EDTA), etc. can be contained for the purposes of fungicides, preservatives, and rust preventives. In addition, urea is used as an antifoaming agent and to prevent nozzle drying.
It can contain thiourea, ethylene urea, etc.

Next, specific examples of acetylene glycols according to the present invention will be shown.

[0019]

[Chemical formula 3]

Compound (B) is m in compound (A).
+n=10. Compound (C) has m+n=30 in compound (A).

[0021]

[C4]

[0022]

[C5]

[0023]

[C6]

[0024]

[C7]

However, the acetylene glycols of the present invention are not limited to the above compounds, and various other structures are possible.

The method for dispersing the aqueous recording ink composition of the present invention includes conventionally used pigment fine dispersion methods, such as ball mills, sand mills, attritor mills, roll mills,
It can be easily produced using an agitator, Henschel mixer, colloid mill, ultrasonic homogenizer, pearl mill, wet jet mill, etc.

In addition, in order to remove coarse particles and mixed substances after dispersion, pressurization or vacuum filtration treatment using a filter is performed in one or more steps, or centrifugation treatment is performed using a centrifuge. It is best to carry out alone or in combination with filtration treatment.

[0028]

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples.

(Example 1) Composition carbon black:

4% by weight (CF9: Mitsubishi Kasei registered trademark) Specific example compound (A):
0
．． 2% by weight dispersant:

1% by weight sodium salt of β-naphthalenesulfonic acid formalin condensate (Labelin FHL: Daiichi Kogyo Seiyaku registered trademark) Solvent: Glycerin

4% by weight ion exchange water

Ink compositions were prepared in Examples using a method containing 90.7% by weight or less. First, twice the predetermined amount of the compound (A) of the specific example of the present invention and a dispersant are dissolved in ion-exchanged water, which is a solvent, and after complete dissolution, carbon black is similarly added in twice the amount. This mixture of dispersant and carbon black was stirred and mixed for 2 hours using a mixer as pre-kneading, and then main dispersion was performed for 8 hours using a sand mill. After that, to remove large particles, use Toyo Roshi No. 2 to remove large particles.
Filtered under reduced pressure at a pressure of kg/cm2, and further filtered to 0.8 μm.
Using an acetyl cellulose membrane filter (manufactured by Toyo Roshi), pressure filtration was performed at a pressure of 1 kg/cm2 to obtain a dispersion. Next, this dispersion was diluted with ion-exchanged water, which is the solvent, and glycerin was further added to adjust the concentration to a predetermined concentration.

Regarding the ink composition thus obtained,
2 using B type viscometer (Tokyo Keiki registered trademark) No. 1 rotor.
The viscosity at 0°C and the surface tension at 20°C were measured using an HLV-ST type surface tension meter (Kyowa Interface Science registered trademark).

In addition, using a prototype 24-nozzle inkjet evaluation machine with a discharge nozzle diameter of 50 μm, a piezoelectric element drive voltage of 120 V, a drive frequency of 2 kHz, and a resolution of 360 dots/inch, PPC paper (PPC paper, a registered trademark of Xerox Corporation) was tested.
, recycled paper (Honshu Paper registered trademark Yamayuri), bond paper (Mead Company registered trademark Gilbert Bond 25% cotton paper),
Solid letters, alphabet letters, etc. were printed on high quality paper (Oji Paper Registered Trademark OK High Quality Paper L) and the following evaluations were performed.

(Test 1) Print quality evaluation by visual inspection of character print samples.

The evaluation results were classified as follows.

[0034] Bleeding is not observed with the naked eye...
・・・・◎ Bleeding can be seen, but the characters can be recognized・
・・・・・・・・・△ Characters cannot be recognized...
・・・・・・・・・・・・・・・×(Test 2) Macb
Density evaluation of solid printed area using eth TR-927 type (Kollomorgan registered trademark) optical densitometer.

The evaluation results were classified as follows.

O. D. Value 1.3 or higher・・・・・・・・・・・・
・・・・◎ O. D. Value 1.1 or more but less than 1.3...
・・・・・・・・・△ O. D. Value less than 1.1...
・・・・・・・・・・・・・・・×(Test 3) 100g
Abrasion resistance evaluation involves rubbing the solid printed area with a cotton cloth at a pressure of /cm2 to check for print stains.

The evaluation results were classified as follows.

No stains on printed matter are observed...
・・・・◎ The printed material is slightly smudged, but the characters can be distinguished. △ The printed material is smudged and the characters cannot be distinguished. . . × (Test 4) Characters Tactile evaluation involves rubbing the printed area with your finger and visually observing the print for dirt. The evaluation results were classified as follows.

[0039] No stains on printed matter are observed.
・・・・◎ The printed material is slightly smeared, but the characters can be distinguished. △ The printed material is smudged and the characters cannot be distinguished. Water resistance evaluation involves dropping water droplets onto the printed text area and visually observing whether or not the ink flows.

The evaluation results were classified as follows.

[0041] No ink flow observed...
・・・・◎ The ink flows, but the letters are legible・
・・・・・・・・・△ Ink flows and the characters are crushed ・・・・・・・・・・・・・・・× (Test 6) After soaking the solid printed area in tap water for 24 hours, check the density change. Immersion evaluation to measure.

The evaluation results were classified as follows.

[0043] The concentration change was within 0.1 in terms of OD value...
・・・・◎ Concentration change was within 0.3 in OD value・・・・・・・・・△ Concentration change was greater than 0.3 in OD value・・・×( Test 7) Continuous ejection stability evaluation to investigate the presence or absence of missing dots during continuous printing at room temperature for 36 hours.

The evaluation results were classified as follows.

Missing dots occur within 10 times within 36 hours...
・・・・◎ Missing dots occur within 10 times within 24 hours・・・・・・・・・△ 1 missing dot within 1 hour
Occurred 0 or more times...× (Test 8) Environmental temperature 70℃ and humidity 85 while the glass sample bottle was sealed
% change in particle size of carbon black particles in 30 days
Storage stability evaluation observed with a 0x transmission microscope.

The evaluation results were classified as follows.

No change in particle size after 30 days...
...◎ A slight change in particle size was observed after 30 days...
・・・・・・・・・△ The grain size clearly became larger after 30 days ・・・・・・・・・× The evaluation results of Example 1 were all ◎.

(Example 2) Compound (A) in the specific example of the present invention was changed to compounds (B) to (G), and in the same manner as in Example 1, Examples 2-1 to 2-1 to Table 1 were prepared. An ink composition was obtained with the composition shown as 2-6. Numerical values in the table, unless otherwise specified, indicate weight %. EDTA is ethylenediaminetetraacetic acid, which is added to the ink as a preservative. As physical property values after ink preparation, viscosity at 20°C,
Surface tension is also listed.

(Comparative Examples 1 to 4) Inks having the compositions shown in Table 1 were prepared in the same manner as in Example 1 to obtain ink compositions.

[0050]

[Table 1]

After ink preparation, Example 2 and Comparative Example 1
The same evaluations as in Example 1 were performed for the ink compositions of Nos. to 4. The results are shown in Table 2.

[0052]

[Table 2]

The ink compositions of Examples 2-1 to 2-6 showed good results in all evaluations. However, as in Comparative Example 1, when the amount of the acetylene glycol compound added according to the present invention is less than 0.01% by weight, its penetration effect is small, resulting in printing stains and poor abrasion resistance and touchability. It became. In addition, there was a slight tendency for particles to agglomerate, resulting in dot dropout and poor storage stability evaluation. Similarly, as in Comparative Example 2, even if the amount of acetylene glycol compound added is appropriate, the ink surface tension is 40 dyn/cm.
As with Comparative Example 1, larger ones are inferior in abrasion resistance and touchability. Further, if more than 10% by weight of the acetylene glycol compound is added as in Comparative Example 3, the solubility in water becomes insufficient, causing dot dropouts and the like. Finally, as in Comparative Example 4, when the ink composition has an ink surface tension lower than 25 dyn/cm, its permeation effect becomes excessive, leading to bleeding of printed matter, decrease in density, and deterioration of water resistance and immersion properties. It's not appropriate. In other words, if the acetylene glycol compound of the present invention has a small number of ethylene oxide groups, it has a large penetration effect but low solubility; on the other hand, if it has a large number of ethylene oxide groups, it has a high solubility in water and a low penetration effect. As discovered in the present invention, the total weight of the ink is 0.
．． Added 01 to 10% by weight to increase the ink surface tension to 25dy.
It is appropriate to adjust it to n/cm to 40 dyn/cm.

(Examples 3 to 9)

[0055]

[Table 3]

Inks of Examples 3 to 9 were prepared in the same manner as in Example 1 using various pigments having the compositions shown in Table 3.

In Table 3, MA100 is a carbon black registered by Mitsubishi Kasei, and Printex 55 is a registered trademark by Degussa. In addition, LutetiaBLDN351 is an azo pigment that is a registered trademark of ICI, KETRed309 is a quinacridone pigment that is a registered trademark of Dainippon Ink & Chemicals, and KETYellow403 is an azo pigment that is a registered trademark of Dainippon Ink & Chemicals.LutetiaCyaninJ4
NS is a phthalocyanine pigment registered by ICI. Catiolite BC-50 is dimethyllauryl benzyl ammonium chloride, a registered trademark of Kyoeisha Yushi Kagaku Kogyo Co., Ltd., and Perex TR is sodium dialkyl sulfosuccinate, a registered trademark of Kao Corporation, and is a surfactant. Denka Poval B-03 is a partially saponified polyvinyl alcohol registered trademark of Denki Kagaku Kogyo Co., Ltd. Further, the numerical value for each ink composition indicates the weight % added. As the physical property values after ink preparation, the viscosity and surface tension value at 20° C. are also listed in Table 3.

(Comparative Examples 5 and 6) As comparative examples, inks with the compositions shown in Table 3 were prepared in the same manner as in Example 1.

The ink compositions of Examples 3 to 9 and Comparative Examples 5 and 6 were evaluated in the same manner as in Example 1.

[0060]

[Table 4]

[0061] Examples 3 to 9 gave good results in all evaluations. Comparative Example 5 is an example in which a water-soluble resin was used for fixing the pigment, but compared to Example 3, the resin component was added in excess, resulting in severe dot dropout, and the water-soluble resin did not have sufficient finger touch and immersion properties. was not obtained. Next, in Comparative Example 6, an anionic surfactant was used to impart a penetrating effect, but in this case, the penetrating effect was excessive, leading to bleeding, a decrease in concentration, and deterioration of water resistance and immersion properties. Furthermore, the ink was unsuitable as an inkjet ink because of its strong foaming properties, which caused dot dropouts.

[0062]

According to the present invention, a novel aqueous recording ink composition can be provided.

Furthermore, according to the present invention, it takes advantage of the high light resistance, chemical resistance, and water resistance of pigments, and also provides abrasion resistance, resulting in high storage stability of recorded materials comparable to electrophotographic methods. This has the effect of providing an aqueous recording ink composition.

Further, even during long-term storage, the carbon black in the ink composition does not aggregate, making it possible to provide an aqueous recording ink composition with excellent ejection stability and storage stability. has.

Claims (3)

[Claims] 1. An aqueous recording ink composition comprising at least a pigment and one or more acetylene glycols represented by the following general formula. [Formula 1] (R1 to R4 are linear and branched alkyl groups having 1 to 6 carbon atoms, and m and n are integers of 1 or more.) 2. The aqueous recording ink composition according to claim 1, wherein the acetylene glycol is contained in an amount of 0.01 to 10% by weight based on the total weight of the ink. 3. Temperature of the aqueous recording ink composition at 20°C.
The surface tension at is 25 dyn/cm to 40 dyn/
The aqueous recording ink composition according to claim 1, wherein the aqueous recording ink composition is in the range of cm.