JP2000265096A - Ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink composition which is used in ink jet recording and gives records free of blur and excellent in dryability. SOLUTION: An ink composition, which at least contains a pigment, a dispersant and water and is used in ink jet recording, is further compounded with (A) fine polymer particles, (B) triethylene glycol butyl ether, (C) a water-soluble organic solvent selected from among ethylene glycol, diethylene glycol, and glycerin, and (D) a water-soluble compound formed by bonding two or three hydroxy groups to a 4-6C hydrocarbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pigment ink suitable for an ink jet recording system for performing recording by discharging ink droplets from a print head and a recording method using the same. More specifically, the present invention relates to a pigment ink that provides high-definition print quality and a recording method using the same.

[0002]

2. Description of the Related Art Dye inks conventionally used for ink-jet recording have disadvantages such as poor light fastness and water fastness, and therefore, some pigment inks having excellent light fastness and water fastness have been used. Have been. However, it has been pointed out that the pigment ink is inferior in print quality or has more blur than the dye ink.

In order to solve the above problem, for example, Japanese Patent Application Laid-Open
Japanese Patent No. 39381 includes a thermoreversible polymer that thickens at a certain temperature or higher, and eliminates bleeding of the recorded matter by heating the recorded matter. Japanese Patent Application Laid-Open No. H10-7692 proposes that the bleeding of a recorded matter is suppressed by binding alginic acid contained in the ink to a polyvalent metal ion on the recorded matter.

[0004] However, the above proposals have limitations in devices and recorded materials, such as the necessity of a heating mechanism in the printer or the need for paper to contain polyvalent metal ions. Therefore, there is a strong demand for the development of ink compositions that can be used in current inkjet printers and that do not limit the type of recorded matter.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pigment ink used for ink jet recording,
An object of the present invention is to provide a pigment ink which eliminates bleeding of a recorded matter and has excellent drying properties of the recorded matter.

[0006]

The object of the present invention is to provide an ink composition for inkjet recording containing at least a pigment, a dispersant and water, comprising (a) polymer fine particles;
(b) triethylene glycol butyl ether, (c) a water-soluble organic solvent selected from the group consisting of ethylene glycol, diethylene glycol and glycerin, and (d) two or three hydroxyl groups in a hydrocarbon having 4 to 6 carbon atoms. The problem is solved by further blending a water-soluble compound to which is bonded.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Regarding the bleeding and drying property of a printed recorded matter, simply increasing drying property increases bleeding, while suppressing bleeding results in poor drying property, and it is difficult to improve both at the same time. there were. However, according to the present invention, at least a pigment, an ink composition used for inkjet recording containing a dispersant and water, (a) polymer fine particles, (b) triethylene glycol butyl ether, (c)
A water-soluble organic solvent selected from the group consisting of ethylene glycol, diethylene glycol and glycerin, and (d)
It has been found that by further blending a water-soluble compound in which two or three hydroxyl groups are bonded to a hydrocarbon having 4 to 6 carbon atoms, both problems of bleeding and drying of printed matter can be solved at the same time.

By using the novel ink composition of the present invention, it is possible to quickly print the recorded matter, eliminate bleeding, and perform printing with high definition printing quality.

The polymer fine particles used in the ink composition of the present invention are preferably composed of a polymer having a glass transition temperature (Tg) in the range of 0 ° C. to 50 ° C. Tg is 0 ° C
If it is less than 5, the recorded matter has adhesiveness, and inconveniences such as sticking between print media occur. On the other hand, Tg
If it exceeds 50 ° C., the polymer fine particles immediately after printing have no fluidity, and the surface smoothness of the recorded matter deteriorates, and the printing quality deteriorates.

[0010] The particle size of the polymer fine particles is not particularly limited. Generally, it is preferable to be within the range of 10 nm to 0.5 μm. When the particle size of the polymer fine particles is less than 10 nm, inconveniences such as the inability to eliminate bleeding of the recorded matter occur. On the other hand, the particle size of the polymer fine particles is 0.5μ.
If it is more than m, nozzle clogging may occur or particles may settle.

The amount of the polymer particles added is preferably in the range of 1 to 10% by weight based on the weight of the ink composition. When the addition amount of the polymer fine particles is within this range, the bleeding of the recorded matter can be eliminated without increasing the viscosity of the ink. The amount of polymer particles added is 1
If the amount is less than wt%, the added amount is too small with respect to the pigment, so that inconveniences such as bleeding of the recorded matter cannot be eliminated. On the other hand, the addition amount of polymer fine particles is 10 wt%
In the case of exceeding, the viscosity of the ink becomes too high, which causes inconveniences such as clogging of nozzles and unstable ink ejection.

The polymer fine particles usable in the present invention include, for example, Johnson Krill 45 manufactured by Johnson Polymer.
0, John Krill 7001, John Krill 711, John Krill 775, John Krill, and the like.

The amount of triethylene glycol butyl ether used in the ink composition of the present invention is preferably in the range of 1 to 10% by weight based on the weight of the pigment ink composition. When the use amount of triethylene glycol butyl ether is less than 1 wt%, bleeding of the recorded matter occurs, and the drying property of the recorded matter is deteriorated. On the other hand, when the use amount of triethylene glycol butyl ether is more than 10% by weight, the optical density of the recorded matter decreases and the viscosity of the ink increases, which causes a problem in the storage stability of the ink.

In the ink composition of the present invention, in addition to water as a solvent, at least one selected from the group consisting of ethylene glycol, diethylene glycol and glycerin is used.
A mixed solvent of various water-soluble organic solvents is used. There is no problem with mixing other organic solvents. For example, triethylene glycol, tripropylene glycol, dimethyl sulfoxide, diacetone alcohol, glycerin monoallyl ether, propylene glycol, polyethylene glycol, thiodiglycol, N-methyl-2
-Pyrrolidone, 2-pyrrolidone, γ-butyrolactone,
1,3-dimethyl-2-imidazolidinone, sulfolane, neopentyl glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monoallyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, Triethylene glycol monomethyl ether, triethylene glycol monoethyl ether,
Propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, β-dihydroxyethyl urea, urea, acetonylacetone, pentaerythritol, hexylene glycol, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono Phenyl ether, diethylene glycol diethyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, propylene glycol monobutyl ether , Dipropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, glycerin monoacetate, glycerin diacetate, glycerin triacetate, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, cyclohexanol , 1-butanol, 2,5-hexanediol, ethanol, n-propanol, 2-propanol, 1-methoxy-2-propanol, furfuryl alcohol, tetrahydrofurfuryl alcohol and the like.

The ink composition of the present invention has 4 to 4 carbon atoms.
A water-soluble compound in which 2 or 3 hydroxyl groups are bonded to hydrocarbon 6 is added. This water-soluble compound is, for example,
1,2-butanediol, 1,4-butanediol, 1,
3-butanediol, 2,4-pentanediol, 1,
5-pentanediol, 2-methyl-2,4-pentanediol, 1,2-cyclohexanediol, 1,4-
Cyclohexanediol, trimethylolethane, trimethylolpropane, 1,2,4-butanetriol,
Examples thereof include 1,2,6-hexanetriol, 1,2,5-pentanetriol, 3-methyl-1,5-pentanediol, and 3-hexene-2,5-diol.
These water-soluble compounds can be used alone or as a mixture of two or more as necessary.

The total content of the water-soluble organic solvent and the water-soluble compound in the ink composition of the present invention is preferably in the range of 8 to 25% by weight based on the weight of the ink composition. This is to prevent nozzle clogging and achieve excellent print quality without delaying the drying time.

The composition ratio of the water-soluble organic solvent to the water-soluble compound in the ink composition of the present invention is 2: 1 by weight.
It is preferably in the range of １ ： 1: 5. This is to prevent nozzle clogging and achieve excellent print quality without delaying the drying time.

The pigment used in the ink composition of the present invention is not particularly limited. In addition to pigments that have been commonly used in the past, pigments newly produced from here can be used as well. As the pigment, a black pigment, a cyan pigment, a magenta pigment, a yellow pigment and the like are used.

As a black pigment, for example, Color Black F
W1, Color Black FW2, Color BlackFW18, Color Black
FW200, Color Black S150, Color Black S160, Color B
lack S170, Printex 35, Printex U, Printex 150T, Pr
intex 75, Printex 85, Special Black 4A, Special Bl
ack 4 (all made by Degussa), No.2300, No.900, No.3
3, No.45, No.2200B, MA7, MA100 (Mitsubishi Chemical Corporation), Monarch700, Monarch800, Monarch900, Monarch1
000 (all manufactured by Cabot Corporation).

As the cyan pigment, for example, CI Pigment
Blue 1, CI Pigment Blue 2, CI Pigment Blue 3, C.
I. Pigment Blue 15: 3, CI Pigment Blue 16, CI Pigm
entBlue 22, CI Pigment Blue 60 and the like.

Examples of the magenta pigment include CI Pigmen
t Red 5, CI Pigment Red 7, CI Pigment Red 12, C.
I. Pigment Red 112, CI Pigment Red 122, CI Pigmen
t Red 123, CI Pigment B Red 168 and the like.

Examples of the yellow pigment include CI Pigmen
t Yellow 12, CI Pigment Yellow 13, CI Pigment Yel
low 14, CIigment Yellow 16, CIigment Yellow
73, CI Pigment Yellow 74, CI Pigment Yellow 83,
CIPigment Yellow 108, CIPigment Yellow 110, C.
I. Pigment Yellow 182 and the like.

The amount of the pigment used in the ink composition of the present invention is from 0.1% by weight based on the weight of the ink composition.
20 wt%, preferably 1.0 wt% to 10 w
It is within the range of t%. Within this range, the color tone and optical density of the ink can be satisfied, and the viscosity and storage stability of the pigment ink can be satisfied.

The pigment used in the ink composition of the present invention preferably has an average particle diameter of 100 nm or less. If it is larger than 100 nm, it tends to settle in the ink, which causes nozzle clogging of the print head.

The dispersant used in the ink composition of the present invention is the same as a known and commonly used one, and is not particularly limited.
The dispersant preferably has a molecular weight in the range of 1,000 to 30,000. When a dispersant having a molecular weight of less than 1000 is used, the dispersion stability of the ink composition may decrease. When a dispersant having a molecular weight of more than 3,000 is used, the viscosity of the ink composition becomes high, and stable ink ejection cannot be performed. The dispersant of the present invention is, for example, a nonionic or anionic dispersant, and these can be used alone or in combination.

The amount of the dispersant of the present invention is in the range of 0.1 wt% to 20 wt% based on the weight of the ink composition. Preferably it is in the range of 0.1 wt% to 10 wt%. When the amount of the dispersant added is within this range, the dispersibility of the pigment particles is improved, and the printing characteristics of the recorded matter can be improved.

The weight ratio of the pigment of the present invention to the dispersant is 1: 2.
It is preferably from 10 to 10. This is to obtain excellent print quality.

The ink composition of the present invention comprises a pigment, a dispersant,
Dispersing a mixed solution containing water, or at least one water-soluble organic solvent selected from the group consisting of ethylene glycol, diethylene glycol and glycerin,
A water-soluble compound in which 2 or 3 hydroxyl groups are bonded to a hydrocarbon having 4 to 6 carbon atoms may be added and dispersed. If necessary, various additives (for example, a surfactant, an antifoaming agent, a bactericide, a humectant, a pH adjuster, etc., which are conventionally used in ink for an ink jet printer) are added to form an ink. . It is also possible to first prepare a dispersion having a high pigment concentration, dilute it by adding a solvent, various additives, and the like, and use the resulting dispersion as an ink.

As the dispersing machine for producing the pigment ink of the present invention, any dispersing machine may be used as long as it is a commonly used dispersing machine. A medium stirring mill such as a high-speed rotation mill or a stirring tank type mill may be used. As a specific method for producing a pigment ink,
There is a method in which ink is dispersed by a planetary ball mill or a sand mill using ceramic beads having a particle diameter of 0.01 to 1.0 mm. In this case, it is preferable that the acceleration is 5 to 50 G in the case of a planetary ball mill and the filling rate of ceramic beads is 50 to 90% and the peripheral speed is 5 to 20 m / s in a sand mill.

The surface tension of the ink composition obtained in the present invention is preferably from 20 to 70 dyne / cm. Also,
The viscosity at 25 ° C. is preferably 10 cP or less, more preferably 5 cP or less. Since water is usually used as a solvent, the viscosity of the ink is 1 cP or more. By having the above-mentioned surface tension and viscosity, the ink composition obtained in the present invention can perform stable printing with an inkjet printer.

The ink composition of the present invention is suitable for use in an ink jet recording method in which a droplet of a pigment ink is ejected from a print head and the droplet is adhered to a recording medium for recording. The recording medium used in the inkjet recording method using the ink composition of the present invention is not particularly limited. In the ink jet recording method using the ink composition of the present invention, if the average surface roughness (Ra) of the recording medium is 1 μm or more, further improvement in print quality can be expected.
This is presumably because polymer fine particles attached to the recording medium smoothed the surface of the recording medium. Average surface roughness (R
A typical recording medium having a) of 1 μm or more is plain paper. The plain paper in this case can provide high-definition printing quality without containing polyvalent metal ions in the paper.

The ink composition of the present invention can be used not only as an ink for an ink jet printer but also as a general aqueous printing ink or paint.
For example, it can be used as ink for a bubble jet printer. Furthermore, the ink composition obtained by the production method of the present invention can be used as a non-aqueous ink or paint by using a non-aqueous organic solvent instead of an aqueous organic solvent.

[0033]

EXAMPLES The ink composition of the present invention will be specifically illustrated below by way of examples.

Example 1 A component having the following composition was dispersed in a sand mill using zirconia beads having a particle size of 0.3 mm for 2 hours to prepare a dispersion. Cyan pigment (CI Pigment Blue 15: 3) 14 parts by weight Dispersant (manufactured by Sanyo Chemicals: Nonipol 400) 8 parts by weight Deionized water 78 parts by weight

While stirring 28 parts by weight of this dispersion, 8 parts by weight of diethylene glycol, 7 parts by weight of trimethylolpropane, 4 parts by weight of triethylene glycol butyl ether, fine polymer particles (manufactured by Johnson Polymer, trade name: Joncryl 7001 42% solution) , Tg = 12
C) 5 parts by weight of ion-exchanged water and 48 parts by weight of deionized water were added dropwise over 30 minutes, and triethanolamine was added to adjust the pH to 8.0 to obtain an ink composition. The pigment particle size was 25 nm.

Example 2 A component having the following composition was dispersed in a sand mill for 1 hour using zirconia beads having a particle diameter of 0.3 mm to prepare a dispersion. 14 parts by weight of black pigment (manufactured by Degussa, trade name: Printex 75) 6 parts by weight of dispersant (manufactured by Shonson Polymer, trade name: 30% solution of Shonkuriru) 6 parts by weight 80 parts by weight ion-exchanged water

While stirring 35 parts by weight of this dispersion, 6 parts by weight of diethylene glycol, 10 parts by weight of trimethylolpropane, and 5 parts by weight of triethylene glycol butyl ether
Parts by weight, polymer fine particles (manufactured by Johnson Polymer, trade name: Joncryl 700142% solution, Tg = 12 ° C.)
After dropwise adding 4 parts by weight and 40 parts by weight of ion-exchanged water over 30 minutes, triethanolamine was added to adjust the pH to 8.
The composition was adjusted to be 0 to obtain an ink composition. The pigment particle size was 30 nm.

Comparative Example 1 An ink composition was prepared in the same manner as in Example 1 except that trimethylolpropane was not used.

Comparative Example 2 An ink composition was prepared in the same manner as described in Example 1, except that diethylene glycol was not added to the composition of Example 1.

Comparative Example 3 An ink composition was prepared in the same manner as described in Example 1 except that triethylene glycol butyl ether was not added to the composition of Example 1.

Comparative Example 4 An ink composition was prepared in the same manner as in Example 1 except that polymer fine particles (manufactured by Johnson Polymer, trade name: Joncryl 7001 42% solution) were not added. Was prepared.

Comparative Example 5 Polymer fine particles A used in Example 1 (manufactured by Johnson Polymer, trade name: Joncryl 7001 42% solution,
(Tg = 12 ° C.) 5 parts by weight of polymer microparticles B (manufactured by Johnson Polymer, trade name: Joncryl 538 45% solution, Tg = 66 ° C.) except that it is changed to 5 parts by weight. An ink composition was prepared in the same manner.

Comparative Example 6 Polymer fine particles A (manufactured by Johnson Polymer, trade name: Joncryl 7001 42% solution used in Example 1)
(Tg = 12 ° C.) An ink composition was prepared in the same manner as described in Example 1, except that 5 parts by weight was changed to 12 parts by weight.

Comparative Example 7 Polymer fine particles A used in Example 1 (manufactured by Johnson Polymer, trade name: Joncryl 7001 42% solution,
(Tg = 12 ° C.) An ink composition was prepared in the same manner as in Example 1, except that 5 parts by weight was changed to 0.5 parts by weight.

Comparative Example 8 An ink composition was prepared in the same manner as in Example 1 except that 4 parts by weight of triethylene glycol butyl ether used in Example 1 was changed to 12 parts by weight.

Comparative Example 9 An ink composition was prepared in the same manner as in Example 1, except that 4 parts by weight of triethylene glycol butyl ether used in Example 1 was changed to 0.5 part by weight.

The ink compositions prepared in Examples 1 and 2 and Comparative Examples 1 to 9 were printed on plain paper (XEROX, 4024, Ra: 1.5 μm) with an ink jet printer, and each ink composition was used. , Clogging, print quality, dryness and bleeding were evaluated. The evaluation results are summarized in Table 1 below.

In Table 1 below, head clogging is caused by
After printing a certain amount of characters with an ink jet printer, leave it at 50 ° C for 7 days without capping etc., then perform a cleaning operation to recover nozzle clogging, and how many times can normal printing be performed? Was determined. The case where normal printing was able to be performed by 1 to 5 times of cleaning operation was evaluated as ○, the case where normal printing was performed by 6 to 10 times of cleaning operation was evaluated as △, and the normal printing was performed with 11 or more times of cleaning operation The case is represented by x.

The print quality was evaluated by measuring the optical density of a solid print portion using a Macbeth portable densitometer (RD-12000 manufactured by Sakata Inx).
The printing quality was evaluated using an optical density value of 1.0 as a reference value. An optical density value of more than 1.0 indicates excellent printing quality.

The drying property is as follows: 150 g / c
plain paper at a pressure of m ² (XEROX Corp., 4024) pressed a, to measure the time until the ink transfer does not occur, the case where ink transfer in less than one second is not observed ◎, the ink transfer at 1 to 2 seconds A case where no ink transfer was observed was evaluated as ○, a case where no ink transfer was observed in 2 to 5 seconds was evaluated as Δ, and a case where ink transfer was observed even for 5 seconds or longer was evaluated as x.

Evaluation of bleeding was performed by printing alphabet letters, and was visually evaluated as ○ when no bleeding was visually observed, Δ when there was bleeding but was not bothersome, and x when there was much bleeding.

[0052]

TABLE 1 Ink composition performance evaluation Clogged print quality Drying Bleeding Example 1 ○ 1.1 ◎ ○ Example 2 ○ 1.1 ◎ ○ Comparative Example 1 × 0.9 ◎ △ Comparative Example 2 × 1.0 ◎ △ Comparative Example 3 △ 1.2 × △ Comparative Example 4 ○ 0.9 ○ × Comparative Example 5 ○ 1.0 ○ △ Comparative Example 6 × 0.8 △ △ Comparative Example 7 ○ 0.9 ○ × Comparative Example 8 ○ 0.8 ○ △ Comparative Example 9 △ 1.2 × △

As is clear from the results shown in Table 1,
Although the ink composition of the comparative example is excellent in several points,
In other respects, they are significantly inferior and are unsuitable as inks for ink jet printers. On the other hand, the ink composition of the present invention is excellent in all aspects of clogging, printing quality, drying properties and bleeding, and is understood to be a well-balanced and excellent ink for ink jet printers. it can.

[0054]

As described above, when the ink composition of the present invention is used as an ink for an ink jet printer, it does not cause clogging of the printer, has excellent drying properties, eliminates bleeding, and has high definition. High print quality.

Continued on the front page (72) Inventor Shigeo Aoyama 1-88 Ushitora, Ibaraki-shi, Osaka F-term in Hitachi Maxell, Ltd. (reference) 2C056 FC01 2H086 BA53 BA55 BA60 BA61 BA62 4J039 BC07 BC09 BC10 BC11 BC12 BC13 BC31 BE01 BE12 BE22 CA06 DA02 EA10 EA15 EA16 EA17 EA19 EA41 EA42 EA44 EA47 GA24

Claims (9)

[Claims] 1. An ink composition for inkjet recording containing at least a pigment, a dispersant and water, comprising: (a) polymer fine particles, (b) triethylene glycol butyl ether, (c) ethylene glycol, A water-soluble organic solvent selected from the group consisting of diethylene glycol and glycerin; and (d) a water-soluble compound in which two or three hydroxyl groups are bonded to a hydrocarbon having 4 to 6 carbon atoms. Ink composition. 2. The ink composition according to claim 1, wherein the polymer fine particles (a) comprise a polymer having a glass transition temperature of 50 ° C. or lower. 3. The ink composition according to claim 1, wherein the blending amount of the (a) polymer fine particles is in a range of 1 to 10% by weight based on the weight of the ink composition. object. 4. The ink according to claim 1, wherein the amount of the triethylene glycol butyl ether (b) is in the range of 1 to 10% by weight based on the weight of the ink composition. Composition. 5. The water-soluble compound (d) includes 1,2-butanediol, 1,4-butanediol, 1,3-butanediol, 2,4-pentanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol,
1,2-cyclohexanediol, 1,4-cyclohexanediol, trimethylolethane, trimethylolpropane, 1,2,4-butanetriol, 1,2,6
2. The composition of claim 1, wherein the compound is selected from the group consisting of -hexanetriol, 1,2,5-pentanetriol, 3-methyl-1,5-pentanediol, and 3-hexene-2,5-diol. Ink composition. 6. The total amount of the water-soluble organic solvent (c) and the water-soluble compound (d) is in the range of 8 to 25% by weight based on the weight of the ink composition. The ink composition according to claim 1, wherein: 7. The composition ratio of the water-soluble organic solvent (c) and the water-soluble compound (d) is in a range of 2: 1 to 1: 5 by weight. The ink composition according to claim 1. 8. The compounding amount of the pigment is in the range of 0.1 to 20% by weight based on the weight of the ink composition, and the compounding amount of the dispersant is based on the weight of the ink composition. 2. The ink composition according to claim 1, wherein the weight ratio of the pigment to the dispersant is in the range of 1: 2 to 10: 1. object. 9. A surface tension of 20 to 70 dyne / cm, 25
The ink composition according to claim 1, wherein the ink composition has a viscosity at 1C in the range of 1 cP to 10 cP.