JP2010007029A - Oil-based ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil-based ink composition which is excellent in smoothness of the beginning of writing by suppressing initial writing thinning as far as possible even when the pen nib is left standing in a state of being in contact with the outside air. <P>SOLUTION: The oil-based ink is characterized in that it is composed of at least a colorant, an oil-soluble resin, an organic solvent selected from an alcohol, a glycol, and a glycol ether, and a hydroxypropyl polyethyleneimine. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention uses an organic solvent selected from alcohols, glycols, and glycol ethers as a solvent, and is a phenomenon in which blurring occurs at the next writing after filling a writing instrument and leaving the pen tip in contact with the outside air. The present invention relates to an oil-based ink that does not easily cause brush blurring.

Conventionally, oil-based inks for writing instruments have the advantage that the handwriting dries quickly, while the pen tip dries when left with the cap removed, and the resin and colorant in the ink dries and cures. There is a problem that defects are likely to occur.
Especially in oil-based inks for ballpoint pens, organic solvents selected from alcohols, glycols, glycol ethers, resins mainly used for fixing on paper, such as ketone resins, xylene resins, rosin-derived resins, and the like It consists of resins whose main purpose is to adjust viscosity, flow characteristics, and prevent bottling, such as polyvinylpyrrolidone and polyvinyl butyral, and oil-based inks for ballpoint pens are used by dissolving these components in high concentrations Therefore, when the tip of the ballpoint pen tip is left in contact with the outside air, the ink at the tip of the ball tip dries out, the viscosity of the ink increases locally, and the ball does not rotate easily during writing. The first brush that does not eject ink from several mm to several tens of mm from the beginning, or the ink ejection temporarily stops during writing Les there has been a easy problem occurs.
In order to solve this problem, polyglycerin fatty acid ester (refer to Patent Document 1), higher fatty acid ester (refer to Patent Document 2), etc. are added to form a solid film on the ink surface of the nib and evaporate the solvent. In addition, a specific phenoxy resin is added to the ink to increase the affinity with the organic solvent and prevent the ink from being completely dried and solidified (see Patent Document 3). It has been known.
Japanese Examined Patent Publication No. 62-34352 (2nd line to 20th line from the top of column 1 on page 1) JP 2001-207100 A (the first line to the 19th line from the top of column 1 on page 1) JP 2000-53907 (paragraph numbers 0005 to 0009)

Conventionally, when an oil-based ink is left in a state where the pen tip is in contact with the outside air, the organic solvent evaporates and causes a first brush blur. Oil-based inks that use organic solvents selected from alcohol, glycol, and glycol ether as solvents also dissolve or disperse oil-soluble dyes, oil-soluble resins, and pigments surrounded by organic solvents selected from alcohol, glycol, and glycol ether. Therefore, if the pen tip is left in contact with the outside air, the organic solvent selected from alcohol, glycol, glycol ether will evaporate and the ratio of oil-soluble dye, oil-soluble resin, pigment, etc. will increase and the viscosity of the ink will increase. Further, the evaporation progresses and the oil-soluble dye and oil-soluble resin are not completely dissolved, and the pigment is agglomerated and the fluidity of the ink is deteriorated. Or so-called first brush blurring.
Even if the specific phenoxy resin was added to prevent the ink from being completely dried and solidified, the viscosity of the tip end of the chip was inevitably increased, and the ink did not flow smoothly, so that the first brush blur could not be prevented sufficiently.
Moreover, there is a limit even if a specific polyglycerin fatty acid ester or a higher fatty acid ester is added to the ink to prevent solidification due to drying and moisture absorption, and it is impossible to sufficiently prevent the first brush blur.
As described above, there was no ink that could be said to be sufficient for the first brush blur.
An object of the present invention is to obtain an excellent oil-based ink that suppresses initial brush blur as much as possible even when the pen tip is left in contact with the outside air and can be written smoothly.

  That is, the present invention is an oil-based ink comprising at least a colorant, an oil-soluble resin, one or more organic solvents selected from alcohols, glycols and glycol ethers, and hydroxypropylpolyethyleneimine. Is a summary.

  The lipophilic part of hydroxypropylpolyethyleneimine acts on oil-soluble dyes, pigments and oil-soluble resins and adsorbs to the surface, thereby forming a large number of hydroxyl groups on the surface of these components. The hydroxyl group of the hydroxypropyl group of this hydroxypropylpolyethyleneimine is hydrogen-bonded with the hydroxyl group of an organic solvent selected from alcohol, glycol and glycol ether, resulting in a strong solvation. As a result, the solubility of oil-soluble dyes, pigments, and oil-soluble resins is improved, and even if the organic solvent selected from alcohol, glycol, and glycol ether evaporates by leaving the tip of the tip in contact with the outside air, it precipitates and aggregates. Since the ink can maintain fluidity without causing ink smearing, it is considered that the first brush blur is unlikely to occur.

The invention is described in detail below.
As the colorant, generally used dyes and pigments can be used. Examples of dyes include SPILON BLACK GMH SPECIAL, SPILON RED C-GH, SPILON RED C-BH, SPILON BLUE C-RH, SPILON BLUE BPNH, SPILON YELLOW C-2GH, SPILON VIOLET C-RH, S. P. T. T. ORANGE6, S. P. T. T. Eisenspiron color such as BLUE111 (manufactured by Hodogaya Chemical Co., Ltd.), Eisen SOT dye, ORIENT SPRIT BLACK AB, VALIFAST BLACK 3804, VALIFAST RED 1320, VALIFAST RED 1360, VALIFAST ORANGE ST VALIFAST BLUE 1601, VALIFAST BLUE 1603, VALIFAST BLUE 1621, VALIFAST BLUE 2601, VALIFAST YELLOW 1110, VALIFAST YELLOW 3104, VALIFAST YELLOW 3105, VALIFAST INDUSTRY Varifast color, orient oil color, rhodamine B base, solder red 3R, methyl violet 2B base, Victoria Blue F4R, etc., and Neo Super Blue C-555 (manufactured by Chuo Synthetic Chemical Co., Ltd.). It is done. Examples of pigments include carbon black, insoluble azo pigments, azo lake pigments, condensed azo pigments, diketopyrrolopyrrole pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, isoindoline pigments, anthraquinones. Conventionally known general pigments such as organic pigments such as pigments, dioxazine pigments, indigo pigments, thioindigo pigments, quinophthalone pigments, perinone and perylene pigments can be used. These may be used alone or in combination of two or more.

Carbon black can be used as the black pigment. For example, Printex 3, 25, 30, 35, 40, 45, 55, 60, 75, 80, 85, 90, 95, 300, Special Black 4, 5, 100, 250, 550 (Degussa Huls Japan Co., Ltd.). Mitsubishi Carbon Black # 2700, # 2650, # 2600, # 2400, # 2350, # 2300, # 2200, # 1000, # 990, # 980, # 970, # 960, Same # 950, Same # 900, Same # 850, Same # 750, Same # 650, Same # 52, Same # 52, Same # 50, Same # 47, Same # 45, Same # 45L, Same # 44, Same # 40, Same # # 33, # 32, # 30, # 25, # 20, # 10, # 5, # 95, # 260, CF9, MCF88, MA600, MA77, MA7, MA11, MA100, MA100R, MA100S, MA100S, MA220, MA230 (above, manufactured by Mitsubishi Chemical Corporation), Talker Black # 8500 / F, # 8300 / F, # 7550SB / F, # 7400, # 736 SB / F, the # 7350 / F, the # 7270SB, the # 7100 / F, the # 7050 (all manufactured by Tokai Carbon Co., Ltd.) and the like.
Examples of blue pigments include C.I. I. Pigment Blue 2, 9, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 16, 17, 28, 29, 36, 60, 68, 76, 80, etc. can be used.
Examples of red pigments include C.I. I. Pigment Red 2, 3, 5, 8, 14, 17, 17, 22, 31, 31, 48: 1, 48: 2, 48: 3, 48: 4, 53 : 1, 53: 2, 57: 1, 112, 122, 144, 146, 149, 166, 170, 175, 176, 177, 179, 184, same 185, 187, 188, 202, 207, 208, 209, 210, 211, 213, 214, 242, 253, 254, 255, 256, 257, 264, 266, 268, 270, 272, etc. can be used.
Examples of yellow pigments include C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 16, 17, 55, 73, 74, 79, 81, 83, 93, 94, 95, the same 97, 109, 110, 111, 120, 128, 133, 136, 138, 139, 147, 151, 154, 155, 167, 173, 174, 175, 176, 180, 185, 191, 194, 213, etc. can be used.
Examples of orange pigments include C.I. I. Pigment Orange 5, 13, 13, 16, 34, 36, 38, 43, 62, 68, 72, 74, and the like.
Examples of green pigments include C.I. I. Pigment Green 7, 36, 37, etc. can be used.
Examples of purple pigments include C.I. I. Pigment Violet 19, 23 and the like can be used.
These dyes and pigments are preferably used in an amount of 1 to 40% by weight, more preferably 1 to 30% by weight, based on the total amount of the oil-based ink. If the amount used is less than 1% by weight, the handwriting is too thin and difficult to read. On the other hand, when the amount is more than 40% by weight, the ink settles with time, and it is liable to cause problems such as inability to write due to clogging, and an increase in viscosity due to an increase in solid content in oil-based ink.

  The organic solvent is the main medium of the ink, and glycol ethers, glycols, and alcohols are preferable. Specific examples include benzyl alcohol, phenyl glycol, phenyl dipropylene glycol, 3-methyl-3methoxybutanol, propylene glycol, dipropylene glycol, isopropyl glycol, isobutyl glycol, methyl diglycol, isobutyl diglycol, hexylene glycol. , Phenyl diglycol, benzyl glycol, benzyl diglycol, propylene glycol monophenyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, Examples include tripropylene glycol monobutyl ether. That. These solvents can be used alone or in combination, and the amount used is preferably 10% by weight or more and 80% by weight or less based on the total amount of the ink.

Oil-soluble resins are added to improve fixability and prevent handwriting show-through, as well as viscosity adjustment and dye dissolution promotion. Ester gum, xylene resin, alkyd resin, phenol resin, polyvinyl pyrrolidone, polyvinyl butyral , Polyvinyl alcohol, acrylic resin, melamine resin, cellulose resin, condensation resin of ketone and formaldehyde such as cyclohexanone, acetophenone, urea, condensation resin of cyclohexanone and resin hydrogenated thereof, maleic acid resin, styrene and malee Copolymers of acid esters, copolymers of styrene and acrylic acid or esters thereof, polyvinyl acetals, polyamides that are condensates of polymerized fatty acids and polyamines, epoxy resins, polyvinyl alkyl ethers, coumarone-indene resins, polyesters Pen, rosin resin and its hydrogenated product, rosin modified maleic acid resin, rosin modified phenolic resin, vinyl pyrrolidone-vinyl acetate copolymer, polymethacrylic acid ester, polyacrylic acid polymethacrylic acid copolymer, Examples include polyoxyethylene.
These resins can be used alone or in combination. The amount used is preferably 0.05 to 30% by weight based on the total amount of the oil-based ink composition.

  Hydroxypropylpolyethyleneimine is used for the purpose of suppressing evaporation of the solvent by hydrogen bonding to prevent drying of the ink and preventing first-scratch blurring. Specifically, propylene oxide-modified polyethyleneimine PP- manufactured by Nippon Shokubai Co., Ltd. 061 (aqueous solution of 48.0 to 52.0% active ingredient). The amount used is preferably 0.2 to 20.0% by weight based on the total amount of ink as pure hydroxypropylpolyethyleneimine. If the amount is less than 0.2% by weight, the effect of preventing the first brush blurring is insufficient, and if added in excess of 20.0% by weight, the viscosity of the ink when the solvent evaporates becomes too high, and it becomes easy to scratch the first brush. There is a possibility that the trouble that the continuation of the ink becomes worse occurs.

In addition, to prevent ink leakage from the pen tip when not in use, or to apply shear thinning to the ink to prevent backflow of ink when the writing tip is left facing upright (upright state) good. Shear thinning agents include cellulose derivatives such as hydroxypropylcellulose, hydroxyethylcellulose, ethylhydroxyethylcellulose, ethylcellulose, water soluble polysaccharides such as hyaluronic acid, copolymers of acrylic acid or methacrylic acid polymers or their alkyl esters. Combined materials, and further cross-linked products thereof, benzylidene sorbitol, silica, bentonite inorganic compounds, organic bentonites, and the like can also be used.
In particular, when shear thinning is imparted to ink for ballpoint pens, the writing quality is improved by preventing leakage of ink when the pen tip is left faced down and by setting the viscosity drop during writing to an optimal value. In order to make it lighter, it is preferable to set the shear thinning index at 25 ° C. to 0.3 or more and 0.9 or less.

A dispersant may be used to disperse the pigment. Those usually used can be used, but polyvinyl butyral and a copolymer containing at least a monomer having a carboxylic acid group in the molecule as a constituent unit are preferable.
In addition to the above components, lubricants and viscosity modifiers, rust preventives, antiseptics, antifoaming agents, anti-scratch agents, dispersants, stringiness imparting agents, and leveling properties used as oil-based ink raw materials as necessary It is also possible to use an organic solvent selected from additives other than alcohol, glycols, glycol ethers, and the like.
Lubricants are used to give smooth writing, but cutting oils, higher fatty acids, phosphate esters, acylamino acids, thiazoles, polyethylene glycol, polypropylene glycol, etc. or their alkyl ethers are generally used. Used. Of these, phosphoric acid esters, polyoxyalkylene alkyl phosphoric acids or neutralized products thereof are preferred because of their great lubricating effect.
When using a solvent other than an organic solvent selected from alcohols, glycols, and glycol ethers, those that are added to the ink and do not hinder dissolution or dispersion of the ink components are preferred. Further, the amount used is preferably an amount that does not adversely affect the fluidity of the ink even when evaporated.

In the present invention, it is usually possible to disperse the pigment by a general method. For example, a pigment and an organic solvent dispersant are mixed and stirred uniformly with a propeller stirrer or the like, and then the pigment is dispersed with a disperser. A dispersing machine such as a roll mill, a ball mill, a sand mill, a bead mill, or a homogenizer is appropriately selected depending on the amount of solvent of the ink and the pigment concentration.
To produce an ink, a colorant, an oil-soluble resin, an organic solvent and hydroxypropyl polyethyleneimine are sufficiently mixed and stirred with a stirrer such as a homomixer, and then other components such as a viscosity modifier and a solvent. It is obtained by mixing oil-based dyes, lubricants, etc. for color tone adjustment, and dissolving and mixing until uniform, but in some cases the mixed ink is further dispersed with a disperser, or the resulting ink It is possible to remove coarse particles and insoluble components by filtering or centrifuging the solution.
In addition, when the ink of the present invention is used for a writing instrument using a fiber core or batting, the ink viscosity is preferably 100 mPa · s or less at 25 ° C. from the viewpoint of ink ejection, and when used for a ballpoint pen, the viscosity is downward for ink ejection or the pen tip. In consideration of ink leakage from the pen tip when left as it is, 200 to 50000 mPa · s is preferable when the shear rate is 1 / s, and 200 to 100000 mPa · s when 1 / s when shear thinning is applied. It is preferable to be 100 to 3000 mPa · s at s, 1000 / s.

Hereinafter, it demonstrates still in detail based on an Example and a comparative example. In each example, “part” simply means “part by weight”.
Example 1
Printex 35 (carbon black, manufactured by Degussa Huls Japan)
5.0 parts Neo Super Blue C-555 (CI Solvent Blue 70, manufactured by Chuo Synthetic Chemical Co., Ltd. 17.3 parts SPILON RED C-GH (oil-based dye, manufactured by Hodogaya Chemical Co., Ltd.) 4.6 Part VALIFAST YELLOW 1151 oil-based dye, manufactured by Orient Chemical Industry Co., Ltd. 3.1 parts diethylene glycol monomethyl ether 41.9 parts ethylene glycol monoisopropyl ether 17.0 parts ESREC BL-1 (polyvinyl butyral, dispersant, Sekisui Chemical Co., Ltd.) Made by Co., Ltd.)
1.6 parts ESREC BH-3 (polyvinyl butyral, viscosity modifier, manufactured by Sekisui Chemical Co., Ltd.) 1.0 part Phosphanol LB400 (phosphate surfactant, lubricant, Toho Chemical Co., Ltd.) 1.5 parts Amit 105 (POE coconut amine, surfactant, manufactured by Kao Corporation) 1.0 part Epomin PP-061 (hydroxypropylpolyethyleneimine aqueous solution, active ingredient 49.7%, Japan) 6.0 parts of the above components Among the above components, Epomin PP-061 was left open at 80 ° C. to evaporate water. Next, the total amount of diethylene glycol monomethyl ether, the total amount of ethylene glycol monoisopropyl ether, and the total amount of S-Rec BL-1 were stirred and mixed and dissolved at 70 ° C. In addition, a dyno mill (bead mill, manufactured by Shinmaru Enterprise Co., Ltd.) was used 10 times using zirconia beads having a diameter of 0.3 mm to obtain a black paste.
Next, the total amount of Neo Super Blue C-555, the total amount of SPILON RED C-GH, the total amount of VALIFAST YELLOW 1151, the total amount of Phosphanol LB400, the total amount of Amite 105, and water were evaporated to this paste. The total amount of Epomin PP-061 and the total amount of Eslek BH-3 were added, stirred and mixed at 70 ° C. for 3 hours, and then allowed to cool to room temperature to obtain a black oil-based ink.
The viscosity of this product was 980 mPa · s at a shear rate of 1 / s.

(Example 2)
SPILON VIOLET C-RH (oil-based dye, manufactured by Hodogaya Chemical Co., Ltd.)
15.0 parts SPILON YELLOW C-GNH (oil-based dye, manufactured by Hodogaya Chemical Co., Ltd.)
10.0 parts diethylene glycol monomethyl ether 28.5 parts ethylene glycol mononormal propyl ether 20.7 parts Hilac 110H (ketone resin, viscosity modifier, manufactured by Hitachi Chemical Co., Ltd.) 6.0 parts PVP-k90 (polyvinylpyrrolidone, Viscosity modifier, manufactured by ISP) 6.0 parts Niimine O-205 (polyoxyethylene oleylamine, surfactant, manufactured by NOF Corporation) 1.0 part phosphanol LS500 (POE alkyl ether phosphate, lubricant) 0.8 part Epomin PP-061 12.0 parts Among the above components, Epomin PP-061 was left at 80 ° C in an open state to evaporate water. To this, all components other than Epomin PP-061 were added, stirred at 70 ° C., and uniformly dissolved to obtain black oil-based ink. The viscosity at a shear rate of 1 / s was 1280 mPa · s.

(Example 3)
NOVOPERM RED F3RK70 (CI Pigment Red 170, manufactured by Clariant Japan Co., Ltd.) 5.0 parts SPILON RED C-GH 15.6 parts SPILON RED C-BH (oil-based dye, manufactured by Hodogaya Chemical Co., Ltd.) 0.8 parts SPILON YELLOW C-GNH 3.8 parts ESREC BL-1 1.6 parts ESREC BH-3 0.5 parts dipropylene glycol monomethyl ether 53.2 parts ethylene glycol monoisopropyl ether 15.4 parts Uniol D2000 ( Polypropylene glycol (manufactured by Nippon Oil & Fats Co., Ltd.) 3.5 parts Epomin PP-061 0.6 part Among the above components, Epomin PP-061 was left open at 80 ° C. to evaporate water. Next, among the above components, the total amount of dipropylene glycol monomethyl ether, the total amount of ethylene glycol monoisopropyl ether, and the total amount of S-Rec BL-1 were stirred at 70 ° C., mixed and dissolved, and then allowed to cool to room temperature. The total amount of NOVOPERM RED F3RK70 was added, and the mixture was passed 10 times with a dyno mill (bead mill, manufactured by Shinmaru Enterprise Co., Ltd.) using zirconia beads having a diameter of 0.3 mm to obtain a red paste.
Next, the total amount of SPILON RED C-GH, the total amount of SPILON RED C-BH, the total amount of SPILON YELLOW C-GNH, the total amount of Uniol D2000, the total amount of ESREC BH-3 and water were evaporated in this paste. The total amount of Epomin PP-061 was added, stirred and mixed at 70 ° C. for 3 hours, and then allowed to cool to room temperature to obtain a red oil-based ink. The viscosity of this product was 1360 mPa · s at a shear rate of 1 / s.

Example 4
SPILON VIOLET C-RH (oil-based dye, manufactured by Hodogaya Chemical Co., Ltd.)
5.0 parts SPILON YELLOW C-GNH (oil-based dye, manufactured by Hodogaya Chemical Co., Ltd.)
2.5 parts diethylene glycol monomethyl ether 28.5 parts ethylene glycol mononormal propyl ether 46.0 parts Hilac 110H (ketone resin, fixing resin, manufactured by Hitachi Chemical Co., Ltd.) 6.0 parts Epomin PP-061 12.0 Part Of the above components, Epomin PP-061 was left open at 80 ° C. to evaporate water. To this, all components other than Epomin PP-061 were added, stirred at 70 ° C., and uniformly dissolved to obtain black oil-based ink. The viscosity at a shear rate of 1 / s was 8 mPa · s.

(Comparative Example 1)
A black oil-based ink was obtained in the same manner as in Example 1 except that ethylene glycol monoisopropyl ether was added instead of evaporated water of Epomin PP-061. The viscosity of this ink was 930 mPa · s at a shear rate of 1 / s.

(Comparative Example 2)
A black oil-based ink was obtained in the same manner as in Example 2, except that ethylene glycol mononormal propyl ether was used in place of the water obtained by evaporating the water of Epomin PP-061. The viscosity of this ink was 1190 mPa · s at a shear rate of 1 / s.

(Comparative Example 3)
A black oil-based ink was obtained in the same manner as in Example 2, except that the amount of Epomin PP-061 added was reduced to 0.3 parts and ethylene glycol mononormal propyl ether was added correspondingly. The viscosity of this ink was 1150 mPa · s at a shear rate of 1 / s.

(Comparative Example 4)
A black oil-based ink was obtained in the same manner as in Example 2, except that the amount of Epomin PP-061 added was increased to 45 parts and diethylene glycol monomethyl ether was reduced accordingly. The viscosity of this ink was 1330 mPa · s at a shear rate of 1 / s.

(Comparative Example 5)
A black oil-based ink was obtained in the same manner as in Example 4 except that ethylene glycol mononormal propyl ether was added in place of the evaporated water of Epomin PP-061. The viscosity of this ink was 6 mPa · s at a shear rate of 1 / s.

As mentioned above, the following test was done about the ink composition obtained by the Example and the comparative example. The results are shown in Table 1.
The viscosity was measured in Examples 1 to 3 and Comparative Examples 1 to 4 with a rheometer VAR-100 manufactured by Jusco International Co., Ltd., a φ20 parallel rotor attached, and a clearance of 0.2 mm from the sample stage. After the adjustment, the shear rate was set to 1 / s in the constant speed item.
In Example 4 and Comparative Example 5, an ELD viscometer manufactured by Tokyo Keiki Co., Ltd. was used, and measurement was performed at a shear rate of 38.3 / s using a cone rotor of 1 ° 34 ′ × R24.
The measurement temperatures are all 25 ° C.

(Preparation of test samples)
Among the oil-based inks obtained in the above Examples and Comparative Examples, Examples 1 to 3 and Comparative Examples 1 to 4 are inks obtained from commercially available jet streams (oil-based ballpoint pens, manufactured by Mitsubishi Pencil Co., Ltd. (ball diameter φ0.7)). 0.3 g was filled in the cleaned part, and centrifugal force was applied with a centrifuge to degas bubbles in the ink, thereby producing a test ballpoint pen.
In Example 4 and Comparative Example 5, a test marker was prepared by removing ink from a commercially available Pentel Pen ENN50 and filling the cleaned parts.

First writing blur test After the writing, the caps were removed and left in a room with a windless temperature of 20 ° C. and a humidity of 40% for Examples 1 to 3 and Comparative Examples 1 to 4 for 24 hours, and Examples 4 and 5 for 2 hours. The length from the beginning of writing to the position of the handwriting that was able to be written normally was measured with a ruler.

  As described above in detail, the oil-based ink of the present invention is an excellent oil-based ink that suppresses initial brush blurring and can be smoothly written even when the pen tip is left in contact with the outside air.

Claims (1)

An oil-based ink comprising at least a colorant, an oil-soluble resin, one or more organic solvents selected from alcohol, glycol, and glycol ether, and hydroxypropylpolyethyleneimine.