JPH08283631A - Ink jet recording ink - Google Patents

Abstract

PURPOSE: To obtain an ink jet recording ink highly rapid in infiltration, almost no blurring even regenerated paper under nonheated state, comprising a water- soluble dye, specific glycol ether-based compound(s), a specific surfactant and water. CONSTITUTION: This ink essentially comprises (A) a water-soluble dye, (B) propylene glycol mono-n-butyl ether and/or dipropylene glycol mono-n-butyl ether, (C) an acetylene glycol-based surfactant pref. <=30 in HLB number at 15 deg.C, and (D) water. Besides, it is preferable that a water-soluble glycol is contained ether at 0.3 to <-20wt. times the component B and at <=40wt.% of the whole ink.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording ink which can obtain high print quality on plain paper, recycled paper, coated paper or OHP paper.

[0002]

2. Description of the Related Art Ink jet recording is a method of recording characters or figures on the surface of a recording medium by ejecting ink as small droplets from fine nozzles. As an ink jet recording method, an electrostrictive element is used to convert an electric signal into a mechanical signal, and the ink stored in the nozzle head portion is continuously or intermittently ejected to record characters or symbols on the surface of a recording medium. Method, the ink stored in the nozzle head portion is rapidly heated in a portion very close to the ejection portion to generate bubbles, and the ink is ejected continuously or intermittently to record characters or symbols on the surface of the recording medium. Methods are being put to practical use.

The ink used for such ink jet recording is required to have characteristics such as good printing dryness, no print bleeding, and uniform printing on all recording medium surfaces. Here, a particular problem is that when paper is used as the recording medium, bleeding is likely to occur due to fibers having different penetrability.

In the conventional ink for ink jet recording, glycol ether is used as a wetting agent as in JP-B-2-2907, a water-soluble organic solvent as in JP-B-1-15542, or JP-B-2-3837. In many cases, it was used as a dye dissolution accelerator as in Japanese Patent Laid-Open Publication No.

Further, in order to improve the permeability, diethylene glycol monobutyl ether is added, as in US Pat. No. 5,156,675, or US Pat. No. 518.
For example, the addition of Surfynol 465, which is an acetylene glycol-based surfactant, as described in US Pat. No. 3,502, or the addition of both diethylene glycol monobutyl ether and Surfynol 465, as described in US Pat. No. 5,196,056. Is being considered. Originally diethylene glycol mono-n-butyl ether was called butyl carbitol, and is described in, for example, US Pat.
No. 91580. Alternatively, U.S. Pat. No. 2,083,372 discusses the use of ethers of diethylene glycol in ink.

[0006]

However, the conventional technique has a problem that it has insufficient penetrability and bleeds onto plain paper, especially recycled paper which has been frequently used due to environmental problems in recent years. Recycled paper is a collection of various paper components mixed with different permeation rates, and therefore easily bleeds due to the difference in their permeation rates. In order to reduce the bleeding, a method of heating the paper during printing is being studied. However, if you heat the paper during printing, it will take time to start up the heating part in the device to the prescribed temperature, the power consumption of the device itself will increase, and the paper and other objects to be printed will be damaged. There is a problem of giving.

Therefore, the present invention solves such a problem, and its purpose is to heat especially plain paper, especially recycled paper which is frequently used in recent years due to environmental problems. The point is that printing without blurring is possible without providing any means.

[0008]

The inkjet recording ink of the present invention comprises at least (A) a water-soluble dye, (B) propylene glycol monobutyl ether and / or dipropylene glycol monobutyl ether, and (C) an acetylene-based surfactant, (D) It is characterized by containing water.

In the present invention, the ink used for ink jet recording is required to have characteristics such as good printing dryness, no print bleeding, and uniform printing on all recording medium surfaces. In view of this, it is the result of intensive study.

In the present invention, the addition amount of (B) propylene glycol monobutyl ether and / or dipropylene glycol monobutyl ether of claim 1 is 10
The closer it is to the weight percent, the less the print bleeding tends to be. In this case, even if the component (B) propylene glycol monobutyl ether and / or dipropylene glycol monobutyl ether of claim 1 is dissolved in water-soluble glycol ether or the like at room temperature, the dye (A) dye or (D ) Phase separation from the water component. In order to suppress this, as a result of intensive studies, it was found that glycols should be used. The viscosity that can be printed by this inkjet method cannot be generally stated because it varies depending on the amount of other additives such as glycols, the amount of dye added, or the ink ejection method. It is preferable to add it so as to be less than 10 mPa · s at ˜40 ° C.).

In the present invention, (A) a water-soluble dye,
(B) propylene glycol monobutyl ether and / or dipropylene glycol monobutyl ether,
When an ink is prepared by adding (C) an acetylene glycol-based surfactant and (D) water, as a component thereof, a preservative,
Antioxidant, conductivity adjuster, pH adjuster, viscosity adjuster,
Additives such as a surface tension adjusting agent, an oxygen absorbing agent, and a nozzle clogging preventing agent can be appropriately used.

The water-soluble glycol ether as a component of the above-mentioned ink-jet ink contains 0.3 to 20 times the amount of propylene glycol mono-n-butyl ether and / or dipropylene glycol mono-n-butyl ether, and 40 times the total amount of the ink. % Or less must be included. If the amount of propylene glycol mono-n-butyl ether is less than 2% of the ink, it does not matter so much, but if it exceeds 2%, if it exceeds about 1% in dipropylene glycol mono-n-butyl ether, the amount of other ink components increases. Will undergo phase separation even at room temperature. 40
At temperatures above ℃, phase separation becomes easier. Therefore, propylene glycol mono-n-butyl ether and /
Alternatively, a water-soluble glycol ether having an amount of dipropylene glycol mono-n-butyl ether of 0.3 times or more is required. Also, propylene glycol mono-n-butyl ether and / or dipropylene glycol mono-
If the amount of the water-soluble organic solvent exceeds 20 times the amount of n-butyl ether or exceeds 60% of the total amount of the ink, it takes a long time to dry the ink and the printing tends to bleed. Therefore, this needs to be 20 times or less and 60% or less of the total amount of ink.

If the concentration of the above-mentioned acetylene glycol-based surfactant is less than 10 PPM, no effect is obtained and no improvement in printing quality is observed, so it is necessary to add more than 10 PPM. Further, if it exceeds 10000 PPM, bubbling or precipitation easily occurs, and stable printing cannot be performed. Therefore, it is necessary to be 10000 PPM or less.

If the surface tension of the above-mentioned ink jet recording ink is not more than 15 mN / m, it becomes difficult to hold the ink on the front surface of the nozzle, and dot omission of printing tends to occur. The permeation speed into the paper becomes slow, and if the paper does not permeate easily, it easily bleeds and print quality deteriorates. Therefore, the surface tension is 1
It should be 5 mN / m or more and 40 mN / m or less.

Examples of the dye (A) include direct dyes, acid dyes, basic dyes, reactive dyes and food dyes. The water-soluble dye C.I. I. Direct dye C. I. Direct Black 2, 4, 9, 11, 14,
17, 19, 22, 27, 32, 36, 41, 48, 5
1, 56, 62, 71, 74, 75, 77, 78, 8
0, 105, 106, 107, 108, 112, 11
3, 117, 132, 146, 154, 168, 17
1, 194, C.I. I. Direct Yellow 1, 2, 4,
8, 11, 12, 24, 26, 27, 28, 33, 3
4, 39, 41, 42, 44, 48, 50, 51, 5
8, 72, 85, 86, 87, 88, 98, 100, 1
10, 127, 135, 141, 142, 144, C.I.
I. Direct Orange 6, 8, 10, 26, 29, 3
9, 41, 49, 51, 62, 102, C.I. I. Direct Red 1, 2, 4, 8, 9, 11, 13, 15, 1
7, 20, 23, 24, 28, 31, 33, 37, 3
9, 44, 46, 47, 48, 51, 59, 62, 6
3, 73, 75, 77, 79, 80, 81, 83, 8
4, 85, 87, 89, 90, 94, 95, 99, 10
1, 108, 110, 145, 189, 197, 22
4, 225, 226, 227, 230, 250, 25
6, 257, C.I. I. Direct violet 1,7,
9, 12, 35, 48, 51, 90, 94, C.I. I. Direct Blue 1, 2, 6, 8, 12, 15, 22, 2
5, 34, 69, 70, 71, 72, 75, 76, 7
8, 80, 81, 82, 83, 86, 87, 90, 9
8, 106, 108, 110, 120, 123, 15
8, 163, 165, 192, 193, 194, 19
5, 196, 199, 200, 201, 202, 20
3,207,218,236,237,239,24
6, 258, 287, C.I. I. Direct Green 1,
6, 8, 28, 33, 37, 63, 64, C.I. I. Direct Brown 1A, 2, 6, 25, 27, 44, 5
8, 95, 100, 101, 106, 112, 173,
194, 195, 209, 210, 211, acid dyes C.I. I. Acid Black 1, 2, 7, 16, 17, 2
4, 26, 28, 31, 41, 48, 52, 58, 6
0, 63, 94, 107, 109, 112, 118, 1
19, 121, 122, 131, 155, 156, C.I.
I. Acid Yellow 1, 3, 4, 7, 11, 12, 1
3, 14, 17, 18, 19, 23, 25, 29, 3
4, 36, 38, 40, 41, 42, 44, 49, 5
3, 55, 59, 61, 71, 72, 76, 78, 7
9, 99, 111, 114, 116, 122, 135,
142, 161, 172, C.I. I. Acid Orange 7, 8, 10, 19, 20, 24, 28, 33, 41,
45, 51, 56, 64, C.I. I. Acid Red 1,
4, 6, 8, 13, 14, 15, 18, 19, 21, 2
6, 27, 30, 32, 34, 35, 37, 40, 4
2, 44, 51, 52, 54, 57, 80, 82, 8
3, 85, 87, 88, 89, 92, 94, 97, 10
6, 108, 110, 111, 114, 115, 11
9,129,131,134,135,143,14
4, 152, 154, 155, 172, 176, 18
0, 184, 186, 187, 249, 254, 25
6, 289, 317, 318, C.I. I. Acid Violet 7, 11, 15, 34, 35, 41, 43, 4
9, 51, 75, C.I. I. Acid Blue 1, 7, 9,
15, 22, 23, 25, 27, 29, 40, 41, 4
3, 45, 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, C.I. I. Acid Green 3, 9, 12, 16, 19, 20, 25, 2
7, 41, 44, C.I. I. Acid Brown 4, 14, basic dye C.I. I. Basic Black 2, 8, C.I. I. Basic Yellow 1, 2, 11, 14, 21, 32, 36,
C. I. Basic Orange 2, 15, 21, 22,
C. I. Basic Red 1, 2, 9, 12, 13, 3
7, C.I. I. Basic Violet 1, 3, 7, 1
0, 14, C.I. I. Basic Blue 1, 3, 5, 7,
9, 24, 25, 26, 28, 29, C.I. I. Basic green 1, 4, C.I. I. Basic brown 1, 1
2. Reactive dye C.I. I. Reactive Black 1, 3, 5, 6, 8, 1
2, 14, C.I. I. Reactive Yellow 1, 2, 3,
12, 13, 14, 15, 17, C.I. I. Reactive Orange 2, 5, 7, 16, 20, 24, C.I. I. Reactive Red 6, 7, 11, 12, 15, 17, 2
1, 23, 24, 35, 36, 42, 63, 66, 8
4, 184, C.I. I. Reactive Violet 2,
4, 5, 8, 9, C.I. I. Reactive blue 2, 5,
7, 12, 13, 14, 15, 17, 18, 19, 2
0, 21, 25, 27, 28, 37, 38, 40, 4
1, C.I. I. Reactive Green 5, 7, C.I. I. Reactive Brown 1,7,16, food dye C.I. I. FOOD BLACK 1, 2, C.I. I. FOOD YELLOW 3, 4, 5, C.I. I. Hooded 2,3,7,9,
14, 52, 87, 92, 94, 102, 104, 10
5, 106, C.I. I. Hood violet 2, C.I. I.
FOOD BLUE 1, 2, C.I. I. There are a few greens.

Other dyes include Kayaset Black 009A manufactured by Nippon Kayaku Co., Direct Deep Black XA, Direct Special Black AXN, Bayscript Black SP Liquid manufactured by Bayer, Revasseur Turquoise Blue KS-6GLL, Pyranin, Sumitomo Chemical Co., Ltd. Manufactured by JI. BK-2, JI. BK-3, Orient Chemical Co., JPK-81L, JPX-127L, JPK-139,
C. I. Flowcent Brightening Agent 1
4, 22, 24, 32, 84, 85, 86, 87, 9
0, 134, 166, 167, 169, 175, 17
6, 177 and the like.

In addition, it improves the solubility of the solvent (B) and dye (A), which are compatible with water and have low solubility in water, and further improve the penetrability into a recording medium such as paper, or As those which can be used to prevent the nozzle from clogging, there are alkyl alcohols having 1 to 4 carbon atoms such as ethanol, methanol, butanol, propanol, and isopropanol, ethylene glycol, diethylene glycol, triethylene glycol, and those having a molecular weight of 600 or less. Polyhydric alcohols or glycols such as polyethylene glycol, 1,3-butylene glycol, glycerin, mesoerythritol, pentaerythritol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether Le, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether,
Diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether,
Ethylene glycol mono-n-butyl ether, diethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-t-butyl ether, triethylene glycol monobutyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, Propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono- n-
Propyl ether, dipropylene glycol mono-is
There are glycol ethers such as o-propyl ether, formamide, acetamide, dimethylsulfoxide, sorbit, sorbitan, acetin, diacetin, triacetin, and sulfolane, which can be appropriately selected and used. On the other hand, the amount is preferably 5 to 60% by weight, and it is necessary to add such an amount that (B) to be added does not cause phase separation at room temperature. If the propylene glycol mono-n-butyl ether and the dipropylene glycol mono-n-butyl ether as the component (B) are less than 3% by weight, the penetrability is insufficient and the printing is bleeding. Separation is likely to occur, and a large amount of the water-soluble organic solvent is required to suppress the separation, which increases the viscosity of the ink, which is not preferable for inkjet. A more preferable addition amount is 2% by weight to 15% by weight.

Further, it is possible to add another surfactant to the ink system in order to further control the permeability or as a dissolution aid of (B). The surfactant to be added is preferably a surfactant having good compatibility with the ink system shown in the present embodiment, and among the surfactants, those having high permeability and stability are preferable. Examples thereof include amphoteric surfactants and nonionic surfactants. Examples of the amphoteric surfactant include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine and other imidazoline derivatives. is there. Nonionic surfactants include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene Ether type such as ethylene alkyl ether, polyoxyalkylene alkyl ether, polyoxyethylene oleic acid, polyoxyethylene oleic acid ester, polyoxyethylene distearate ester, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesqui Esters such as oleate, polyoxyethylene monooleate, polyoxyethylene stearate, etc. Alkyl esters, and the like fluorine-containing surfactants such as perfluoroalkyl carboxylates.

Further, for example, as a preservative / antifungal agent, sodium benzoate, pentachlorophenol sodium,
2-Pyridinethiol-1-oxide sodium, sodium sorbate, sodium dehydroacetate, 1,2
-Dibenzisothiazolin-3-one (Proxel CRL, Proxel BDN, Proxel GXL, Proxel XL-2, Proxel TN, manufactured by ICI) may be added.

Alternatively, amines such as diethanolamine, triethanolamine, propanolamine and morpholine as pH adjusting agents, dye dissolution aids or antioxidants and their modified products, potassium hydroxide, sodium hydroxide, and hydroxide. Inorganic salts such as lithium, ammonium hydroxide, quaternary ammonium hydroxide (tetramethylammonium, etc.), carbonates such as potassium carbonate, sodium carbonate, lithium carbonate, and other phosphates, or N-methyl-2-pyrrolidone, urea , Thiourea,
There are ureas such as tetramethylurea, alohanates, alohanates such as methylallohanate, burettes such as burette, dimethyl burette and tetramethyl burette, and L-ascorbic acid and salts thereof. Further, commercially available antioxidants, ultraviolet absorbers and the like can also be used. Examples include Ciba Geigy's Tinuvin 328, 900, 1130, 384,
292, 123, 144, 622, 770, 292, I
rgacor252, 153, Irganox101
0, 1076, 1035, MD1024, etc.

Further, as the viscosity modifier, rosins,
Examples include alginic acid, polyvinyl alcohol, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, polyacrylate, polyvinyl pyrrolidone, and gum arabic starch.

[0022]

EXAMPLES Next, (A) water-soluble dye, (B) propylene glycol monobutyl ether and / or dipropylene glycol monobutyl ether, (C) acetylene glycol-based surfactant, and (D) which are the main features of the present invention.
Specific examples and comparative examples of forming an inkjet ink using water will be shown. The amount added in the examples is% by weight, 0.1 to 1% by weight of Proxel XL-2 in the remaining water to prevent ink corrosion, and benzox to prevent ink jet head member corrosion. Triazole was added at 0.001 to 0.05% by weight. Also, (4)
2,4 as the acetylene glycol surfactant
Acetylene glycols such as 7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol and 3,5-dimethyl-1-hexyne-3ol (For example, Nisshin Kagaku Surfynol 104, 82, 465, 485 or TG)
Was used.

Example 1 Addition amount CI Direct Black 19 2.0 PGmBE 7.0 DEGmBE 7.0 1,4-butanediol 5.0 1,6-hexanediol 5.0 2-pyrrolidone 2.0 thiodiglycol 3.0 Surfynol 104 1.0 Deionized water residual amount Example 2 CI Food Black 2 2.0 DPGmBE 5.0 TEGmBE 10.0 Dipropylene glycol 5.0 Tripropylene glycol 5.0 Urea 5.0 Surfy Nol TG 1.2 Fluorosurfactant 0.1 Ion-exchanged water Remaining amount Example 3 CI Basic Yellow 1 1.5 PGmBE 5.0 MMB 10.0 Propylene glycol 7.0 Triethylene glycol 3.0 1,5 -Pentanediol 5.0 Surfynol TG 1.4 Ion-exchanged water residue Example 4 Special black SP liquid 3.0 DPGmBE 5.0 PGmEE 10.0 1,6-hexanediol 5.0 tripropylene glycol 2.0 DMI 2.0 Surfynol 104 0.8 Surfynol 465 0.4 ion Exchanged water residual amount Example 5 Direct Blue 199 3.0 PGmBE 5.0 DPGmME 10.0 MPD 3.0 trimethylolpropane 3.0 N-methylpyrrolidone 3.0 Surfynol TG 1.2 Ion-exchanged water residual amount implementation Example 6 CI Reactive Red 6 2.5 PGmBE 5.0 DPGmBE 2.0 DEGmBE 10.0 neopentyl glycol 5.0 diethylene glycol 5.0 Surfynol TG 0.5 Cyfinol 104 0.5 ion-exchanged water residual amount Example 7 CI Acid Green 9 3.0 DPGmBE 5.0 TEGmBE 10.0 Glycerin 5.0 Trimethylolpropane 5.0 Trimethylolethane 5.0 PEG 2.0 with number average molecular weight 400 400 Surfynol 465 1.0 Surfynol TG 0.6 Triethanolamine 0.1 Ion-exchanged water Remainder Example 8 CI Direct Green 1 1.5 CI Direct Green 28 1.0 DPGmBE 5.0 DEGmtBE 5.0 DEGmBE 5.0 Diethylene glycol 5.0 Tetrapropylene glycol 5.0 1,3-Propanediol 5.0 Surfynol 104 1.0 Deionized water residual amount Comparative Example 1 CI Direct Green 1 2.0 DEGmBE 10.0 Ethylene glycol 8.0 Potassium hydroxide 0.1 Deionized water residual amount Comparative example 2 CI Direct Red 227 2.5 DEGmBE 10.0 Diethylene glycol 10.0 Glycerin 5.0 Ion-exchanged water Remaining amount Comparative Example 3 CI Acid Red 254 2.5 DEGmBE 10.0 Diethylene glycol 10.0 Surfynol 465 1.0 Ion-exchange Water balance PGmBE is propylene glycol mono-n-butyl ether, DEGmBE is diethylene glycol mono-n
-Butyl ether, DPGmBE is dipropylene glycol mono-n-butyl ether, TEGmBE is triethylene glycol mono-n-butyl ether, MMB is 1-methyl-1-methoxybutanol, PGmEE is propylene glycol monoethyl ether, DMI is 1,
3-Dimethyl-2-imidazolidinone, DPGmME is dipropylene glycol monomethyl ether, MPD is 2-methyl-2,4-pentanediol, PEG is polyethylene glycol, and DEGmtBE is diethylene glycol mono-t-butyl ether.

Next, Table 1 shows the results of printing evaluations using the ink jet recording inks prepared by the method of the present invention shown in these Examples and Comparative Examples. In Table 1, bleeding indicates fine non-uniformity of penetration that reduces the roundness of dots, and whiskers indicate non-uniformity of linear penetration that extends in stripes along the fibers of paper. The symbols shown in Table 1 represent ⊚ extremely good, ○ good, △ bad, and extremely bad. The measurement of this print evaluation was performed by an inkjet printer MJ-700V2C manufactured by Seiko Epson Corporation.

[0025]

[Table 1]

As can be seen from the results in Table 1, by using the ink jet recording ink according to the present invention, almost all papers have no bleeding or beard, and particularly good printing is possible even on recycled paper. I understand. This can be realized only by combining propylene glycol mono-n-butyl ether and / or dipropylene glycol mono-n-butyl ether with an acetylene glycol-based surfactant, but water solubility cannot be ensured only by these. When using a water-soluble dye, a water-soluble solvent such as a water-soluble glycol ether is always required. Therefore, in the present invention, at least (A) a water-soluble dye and (B) propylene glycol mono-
It is characterized by containing n-butyl ether and / or dipropylene glycol mono-n-butyl ether, (C) acetylene glycol-based surfactant, and (D) water, and shows that it can be realized only by these combinations. .

Next, a water-soluble glycol ether as a component of the above-mentioned ink jet recording ink is contained in an amount of 0.3 to 20 times the amount of propylene glycol mono-n-butyl ether and / or dipropylene glycol mono-n-butyl ether. It is explained that it is necessary to contain 40% or less of the total ink. When the amount of propylene glycol mono-n-butyl ether is less than 2% by weight of the ink, it does not matter so much, but when it exceeds 2% by weight, the amount of dipropylene glycol mono-n-butyl ether exceeds about 1% by weight. Other ink components undergo phase separation even at room temperature. At 40 ° C or higher, phase separation becomes easier. Therefore, it is necessary to use a water-soluble glycol ether in which the amount of propylene glycol mono-n-butyl ether and / or dipropylene glycol mono-n-butyl ether is 0.3 times or more. Also,
If the amount of propylene glycol mono-n-butyl ether and / or dipropylene glycol mono-n-butyl ether exceeds 20 times or the amount of water-soluble glycol ether exceeds 40% by weight of the total amount of ink, it takes a long time to dry the ink, resulting in printing failure. It tends to bleed easily. Therefore, the addition amount must be 20 times or less and 40% by weight or less of the total amount of ink.

When the HLB of the acetylene glycol-based surfactant of the present invention at 15 ° C. exceeds 30, foaming tends to be large, and therefore foaming tends to take time and the printing tends to be unstable due to the foaming. . Therefore,
HLB needs to be added so as to be 30 or less at 15 ° C. However, since the actual use temperature of the ink for inkjet recording is about 5 ° C. to 40 ° C., it is necessary that the foaming property is low in that temperature range, and it is necessary to prevent a phase separation phenomenon such as a cloud point from occurring. .

Further, the results of changing the surface tension with the composition of Example 1 will be described. The surfactant of the ink of the composition of Example 1 was added to the composition excluding the surfactant of the ink of Example 1 by changing the kind and concentration of the surfactant and blended so as to reduce the surface tension. And a composition obtained by adding a small amount of diethylene glycol mono-n-butyl ether to the composition excluding propylene glycol-n-butyl ether and blended so as to increase the surface tension. as a result,
If the surface tension of the ink jet recording ink used in this example is not less than 15 mN / m, it becomes difficult to retain the ink on the front surface of the nozzle, and dot omission of printing is likely to occur. Further, it has been found that when the value exceeds 40 mN / m, the permeation speed of the printing into the paper becomes slow, and the paper which is difficult to permeate tends to bleed and the printing quality tends to deteriorate. Therefore, the surface tension is 15 mN / m or more 4
It should be 0 mN / m or less.

Further, when the viscosity of the ink jet recording ink according to the present invention is 3 mPa · s or more at room temperature, the ink is ejected so that the solvent such as the water content of the ink at the nozzle tip is not dried to cause ejection failure. Stable printing was possible by using a mechanism that vibrates so that the ink is not ejected when it is not. This is 3mP
If it is less than a · s, there is no problem even if such a mechanism is not provided. However, in the present invention, since the ink rapidly penetrates into the recording medium, the amount of the dye added tends to increase, and therefore the viscosity often exceeds 3 mPa · s. Therefore, the ink jet recording ink according to the present invention needs to use this mechanism.

Further, the ink jet recording ink according to the present invention has a tendency that the ink adheres to the front surface of the nozzle to cause printing disorder as compared with the conventional example. To prevent that,
As shown in Example 2, the problem could be solved by adding a fluorine-based surfactant. The addition amount is preferably 1 PPM or more and 10000 PPM or less of the amount of ink.
If the addition amount is less than 1 PPM, the effect of suppressing the print disorder is low, and if it exceeds 10,000 PPM, the foaming becomes intense and it takes a lot of time to suppress the foaming, or the surface tension of the ink tends to decrease, resulting in dot omission. Therefore, the amount of the fluorine-based surfactant is 1 PPM or more and 10000 or more in the ink amount.
It is necessary to add PPM or less. This effect is effective not only in the embodiment shown in the present invention but also in other similar systems incorporating the gist of the present invention.

Next, the ink jet recording ink according to the present invention contains propylene glycol mono-n-butyl ether and / or dipropylene glycol mono-n-butyl ether having a low solubility in water or an acetylene glycol-based surfactant having a low HLB. Since it is contained, phase separation easily occurs at high temperature. Therefore, in order to prevent this, glycol such as thiodiglycol is used in an amount of 3% by weight or more 2
It has been found that it is preferable to contain 5% by weight or less. If it is less than 3%, the effect of suppressing phase separation is low, and if it exceeds 25% by weight, the viscosity is increased and the addition amount of the dye or other additives is limited. It was also found that the inclusion of glycols such as thiodiglycol reduces printing defects due to drying of the ink on the front surface of the nozzle. In addition to thiodiglycol, it has such effects as
1,4-butanediol, 1,5-pentanediol,
There was a single substance or a mixture of 1,6-hexanediol, propylene glycol, dipropylene glycol, tripropylene glycol, neopentyl glycol, 2-methyl-2,4 pentanediol, trimethylolpropane, trimethylolethane and the like.

From the above, propylene glycol-
Water-soluble for practical use based on improvement of print quality such as reduction of bleeding and beard on recording medium such as paper by combination of n-butyl ether or dipropylene glycol-n-butyl ether and acetylene glycol surfactant Suppression of phase separation by glycol ether,
Addition amount of acetylene glycol type surfactant and HLB
Limitation, surface tension regulation, adoption of ink vibration mechanism at the nozzle tip, reduction of print disturbance due to fluorochemical surfactant, phase separation due to addition of glycols and reduction of print disturbance due to ink drying at the nozzle tip It is shown that a highly practical ink jet recording ink can be obtained by the above.

The present invention should not be considered to be limited to these examples, and various modifications can be made without departing from the spirit of the present invention.

[0035]

As described above, according to the present invention, there is provided an ink jet recording ink capable of printing with almost no bleeding on plain paper which has hitherto been insufficient, particularly recycled paper which has been frequently used due to environmental problems in recent years. It has the effect of providing. In addition, the ink does not undergo phase separation even at high temperatures, and is stable, and since the intermittent printable time can be lengthened, waste of ink is reduced and printing throughput can be increased.

Claims (8)

[Claims] 1. At least (A) a water-soluble dye, (B) propylene glycol mono-n-butyl ether and / or
Or dipropylene glycol mono-n-butyl ether, (C) acetylene glycol-based surfactant, (D)
An inkjet recording ink comprising water. 2. A water-soluble glycol ether as a component of the ink for inkjet recording is 0.3 to 20 times the amount of the (B) propylene glycol mono-n-butyl ether and / or dipropylene glycol mono-n-butyl ether. Less than 40% by weight of the total ink
The ink for inkjet recording according to claim 1, comprising: 3. The non-ionic surfactant of the acetylene glycol-based surfactant, which has a concentration of 10 PPM or more and 10000 PPM or less.
The ink jet recording ink according to item 1. 4. The ink jet recording ink according to claim 1, wherein the HLB of the acetylene glycol-based surfactant is 30 or less at 15 ° C. 5. The inkjet recording ink according to claim 1, wherein the surface tension of the inkjet recording ink is 15 mN / m or more and 40 mN / m or less. 6. The inkjet recording apparatus according to claim 1, further comprising a mechanism that vibrates so that the ink at the nozzle tip is not ejected when the viscosity of the inkjet recording ink is 3 mPa · s or more at room temperature. ink. 7. The inkjet recording ink according to claim 1, wherein the inkjet recording ink contains a fluorine-based surfactant in an amount of 1 PPM or more and 10000 PPM or less. 8. The inkjet recording ink according to claim 1, wherein the inkjet recording ink contains glycols in an amount of 3% by weight or more and 25% by weight or less.