JP5900097B2 - Oil-based ink composition for ballpoint pens - Google Patents

Description

  The present invention relates to an oil-based ink composition for ball-point pens, and more particularly to an oil-based ink composition for ball-point pens that does not leak ink, has a light writing taste, and has no handwriting blur.

Ink for ballpoint pens, if the viscosity of the ink is made pseudoplastic by adding a shear thinning agent, the viscosity of the ink is high when standing, but due to the shear force caused by the rotation of the ball applied to the ink when writing. The viscosity drops and the ink flows and ejects. A technique for imparting such shear thinning to ink for the purpose of preventing ink leakage and light writing is well known.
Among them, the cellulose derivatives described in Patent Document 1 and Patent Document 2 impart large shear thinning to the ink with a relatively small addition amount compared to other general-use shear thinning imparting agents. The viscosity is sufficiently lowered by the shearing force generated by the rotation of the ball, and a very light writing feeling can be obtained.
However, since the cellulose derivative is a derivative of cellulose having a property of strongly crystallizing by strong hydrogen bonding between hydroxyl groups to impart solvent solubility, the size and structure of the substituent, or the substitution was not performed. Depending on the residue, the crystallization property remains, and the dissolution method is very difficult. If the crystallization property is left as it is, the shear thinning property may be weakened, or the handwriting may be blurred due to clogging with undissolved substances.
In addition, when cellulose derivatives are added to the ink, only the surface of the cellulose derivative particles is quickly swollen by the solvent in the ink, so that the molecular chains are tightly packed only on the particle surface, and the solvent is less likely to penetrate into the interior. It tends to be in the state of a spatter. If the particles are in the form of a powder, the solvent does not reach the center of the particles, and the cellulose derivative particles cannot be dissolved in the medium, and the particles block the ink passages, resulting in blurring of handwriting.
Conventionally, as an attempt to make the dissolution state of such a cellulose derivative in ink appropriate, Patent Document 3 discloses that benzyl glycol or benzyl polyglycol is added to the ink to expand the molecular chain of the cellulose derivative and dissolve it. The example in which the spinnability is increased to prevent bottling by adding a polyhydric alcohol into the ink and improving the solubility by making the cellulose derivative amorphous, An example in which coarse undissolved particles are reduced and ink filterability is improved is disclosed.

JP 2008-133385 A JP-A-5-339533 JP 2007-231139 A JP 2008-13585 A

  Methyl cellulose having a small hydrophobic group and hydroxypropyl cellulose having a large number of hydroxyl groups in the molecule, such as the invention described in Patent Document 1, have strong water-solubility, and therefore have low solubility and solvent retention in organic solvents, and are oil-based. When used in ink, the problem of handwriting blurring due to undissolved material and solvent separation phenomenon could not be solved.

In each of the inventions described in Patent Documents 2 to 4, a solvent having a hydroxyl group is used, and the hydroxyl group in the molecule of the solvent has a strong hydrogen bond between the hydroxyl groups in the cellulose derivative or between the molecules. The improvement of solubility can be expected by cutting.
However, any of these solvents used has a solubility parameter (the value of the square root of the molecular cohesive energy) of 9.6 (cal / cm ³ ) ^1/2 or more. The solubility parameter of ethyl cellulose is 10.3 (cal / cm ³ ) ^1/2. A solvent having a solubility parameter close to this has high affinity and high solubility. A powder is formed and a sufficient dissolved state cannot be formed. When the solubility parameter is too high at about 11 (cal / cm ³ ) ^1/2 , the cohesive strength of the solvent itself increases, and the solvent cannot permeate into the ethylcellulose particles. May not be maintained, and insoluble matter may be precipitated.

That is, the present invention provides a colorant, ethyl cellulose, and a solubility parameter (SP value) of 8.0 (cal / cm ³ ) ^{1/2 to} 9.5 (cal / cm ³ ) ^1/2 in the molecule. The organic solvent containing an oxypropylene group is 1.0% by weight or more in the ink, and the solubility parameter (SP value) is 8.0 (cal / cm ³ ) ^1/2 or more 9.5 (cal / cm ³ ) ^{1 The} oil-based ink composition for ballpoint pens containing at least 1.0% by weight or more of an organic solvent containing a hydroxyl group in the molecule and not containing an oxypropylene group at a molecular weight of ² or less is used. An organic solvent having an SP value of 8.0 (cal / cm ³ ) ^1/2 or more and 9.5 (cal / cm ³ ) ^1/2 or less and containing a hydroxyl group in the molecule and no oxypropylene group is 20 ° C. smell The ballpoint pen oil-based ink composition are those which are soluble in infinite water to a second aspect, the solubility parameter (SP value) of 8.0 (cal ^/ cm ^{3) 1/2} or more 9.5 (cal / cm ³ ) The third gist is an oil-based ink composition for ballpoint pens in which the organic solvent containing a hydroxyl group in the molecule and not containing an oxypropylene group is ^½ or less and the structure does not contain an oxyethylene group in the molecule. .

The solubility parameter in the present invention indicates the SP value proposed by Hildebrand (hereinafter simply referred to as SP value), and the unit is (cal / cm ³ ) ^1/2 (hereinafter, the unit is omitted). And the value at 20 ° C.
The oil-based ink composition for ballpoint pens of the present invention has an SP value of the solvent of 8.0 to 9.5, so that the cohesive strength of these solvents is moderate and also has an affinity for ethyl cellulose. . And since these solvents use together what contains an oxypropylene group in the molecule and one that contains a hydroxyl group in the molecule and does not contain an oxypropylene group, the oxypropylene group temporarily becomes a hydrogen bond of ethyl cellulose, etc. The oxypropylene group does not have a strong affinity for ethylcellulose, so it does not bind strongly to the hydrophilic group or hydrophobic skeleton of ethylcellulose, but temporarily protects it. It is considered that the action of breaking the hydrogen bond of the hydroxyl group itself is not hindered, but can simply delay the progress. As a result, an organic solvent containing a hydroxyl group in the molecule and not containing an oxypropylene group is bonded to the crystallized hydroxyl group or skeleton of ethyl cellulose at a slow rate despite having a reasonably high solubility in the resin. As a result, the resin particles are prevented from becoming a powdered state, and the solvent itself has a large penetrating power. It is presumed that a preferable dissolution state is obtained, ethylcellulose does not dissolve sufficiently, becomes a sprinkled particle, inhibits the flow of ink, blurs the handwriting, and suppresses the solvent separation phenomenon over time. .
In addition, when an organic solvent having an SP value of 8.0 or more and 9.5 or less and containing a hydroxyl group in the molecule and not containing an oxypropylene group is infinitely miscible with water, the ink can be used in a high humidity environment. Even when moisture absorbs water, the components are mixed uniformly, so that water does not exist as a separated layer in the ink, and precipitation due to partial insolubilization of ethyl cellulose does not occur.
Also, if there are oxyethylene groups in the solvent molecules, the viscosity of the solvent increases due to the hydrogen bonding force between the oxyethylene groups, so the penetrating power to the solute tends to decrease, but the SP value is 8.0 or more. Since the organic solvent having a hydroxyl group in the molecule of 9.5 or less and not containing an oxypropylene group has a structure that does not contain an oxyethylene group in the molecule, it has a higher osmotic power for the solute. Can be dissolved better. In addition, the hydrogen bond strength of oxyethylene groups is highly temperature dependent. At low temperatures, there is a concern that the solubility of ethyl cellulose may decrease due to increased cohesion between solvents, but it contains oxyethylene groups in the solvent molecules. Otherwise, the temperature dependency of the cohesive force of the solvent is reduced, so that the change in solubility is small even at low temperatures.

As the colorant, either a dye or a pigment can be used, and a dye and a pigment can be used in combination. However, it is preferable to use at least a pigment because of the effect of shear thinning property.
When a pigment is used as the colorant, a conventionally known pigment can be used.
Examples of organic pigments include C.I. I. PIGMENT RED2, 3, 5, 8, 17, 17, 31, 31, 38, 41, 48: 1, 48: 2, 48: 3, 49, 50, 53: 1, 57: 1, 58: 2, 60, 63: 1, 63: 2, 64: 1, 88, 112, 122, 123, 144, 146 149, 166, 168, 170, 170, 176, 177, 178, 179, 180, 185, 190, 194, 202, 206, 207, 209, 211, 213, 216, 245, 254, 254, 255, 264, 270, 272, C.I. I. PIGMENT ORANGE 5, 10, 13, 16, 36, 40, 43, 61, 64, 71, 73, C.I. I. PIGMENT VIOLET 19, 23, 31, 33, 36, 37, 38, 50, C.I. I. PIGMENT BLUE 2, 9, 15, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 5, 15: 6, 16, 16, 17, 22, 25, 28, 29, 36, 60, 66, 68, 76, C.I. I. PIGMENT BROWN 23, 25, 26, C.I. I. PIGMENT YELLOW 1, 3, 12, 13, 24, 83, 93, 94, 95, 97, 99, 108, 109, 110, 117, 120, the same 128, 139, 147, 151, 153, 166, 167, 173, C.I. I. PIGMENT GREEN 7, 10, 36, C.I. I. PIGMENT BLACK 7 etc. are mentioned.
As inorganic pigments, carbon black such as furnace black, channel black, thermal black, acetylene black, black iron oxide, yellow iron oxide, red iron oxide, ultramarine blue, bitumen, cobalt blue, titanium yellow, turquoise, molybdate orange, Examples include titanium oxide.
As other pigments, fluorescent pigments, pearl pigments, phosphorescent pigments, metal pigments, composite metal pigments, metal oxide pigments and the like may be used. For example, the fluorescent pigments include FZ-5012, FZ-5005, FZ-5006, FZ-5006, FZ-6011, FZ-6013, FZ-6014, FZ-6037, FZ-MB, FZ-PR, FZ-SB. FZ-5000 / 6000 series (Shinloihi Co., Ltd.) etc. are mentioned. Examples of the pearl pigment include Pearl Glaze MRY-100 and ME-100 (manufactured by Nippon Koken Chemical Co., Ltd.). GSS (Nemoto Special Chemical Co., Ltd.) etc. are mentioned as a luminous pigment. In addition, the metal pigment is used for the purpose of producing a glitter feeling different from the color of the handwriting, and examples thereof include aluminum powder, bronze powder, zinc powder, and the like. 22000, ibid. 18000, Fine No. 900, ibid. 800 (above, manufactured by Daiwa Metal Powder Industry Co., Ltd.).
These pigments can be used alone or in combination of two or more, and the amount used is preferably 10 to 60% by weight based on the total amount of the ink composition when used alone as a colorant.

In order to increase the dispersion efficiency of the pigment, a polymer compound obtained by finely dispersing a pigment in advance may be used. In particular, when such a processed pigment is used, it can be easily dispersed in production, and can be used as a useful means in production. For example, Microlith Yellow 2G-T, Yellow 3R-T, Brown 5R-T, Scarlet RT, Red BR-T, Blue GS-T, Green GT, Black CT (pigment finely dispersed in rosin ester resin, manufactured by BASF, Germany), Microlith Yellow 4G-A, Yellow MX-A, Yellow 2R-A, Brown 5R-A, Scarlet R- A, Red 2C-A, Red 3R-A, Magenta 2B-A, Violet B-A, Blue 4G-A, Green G-A, Black C-A, White R-A ( Pigment finely dispersed in ethyl cellulose resin, manufactured by BASF, Germany), L1 / S Yellow NIF, L1 / 8 F3RK-70, L1 / 8 violet RN50, L1 / 8 orange 501, L1 / 8 brown 5R, L1 / 8 black MA100, NC790 white (pigment finely dispersed in nitrocellulose resin, manufactured by Taihei Chemical Products Co., Ltd.) Etc.
These processed pigments can be used alone or in combination of two or more, and can also be used in combination with the above-mentioned various pigments. The amount of the pigment used is 10 to 60% by weight based on the total amount of the ink composition as a pigment component when used alone as a colorant.

In the case of using a dye as the coloring material, a conventionally known dye can be used. I. Direct Black 17, 19, 19, 22, 32, 38, 51, 71, C.I. I. Direct Yellow 4, 26, 44, 50, C.I. I. Direct Red 1, 4, 23, 31, 37, 39, 75, 80, 81, 83, 225, 226, 227, C.I. I. Direct blue 1, 15, 41, 71, 86, 87, 106, 108, 199, and the like; I. Acid Black 1, 2, 24, 26, 31, 31, 52, 107, 109, 110, 119, 154, C.I. I. Acid Yellow 1, 7, 17, 19, 23, 25, 29, 38, 42, 49, 61, 72, 78, 110, 127, 135, 141, 142, C.I. I. Acid Red 8, 9, 9, 14, 26, 27, 35, 37, 51, 52, 57, 82, 83, 87, 92, 94, 111, 129, 131, 138, 186, 249, 254, 265, 276, C.I. I. Acid Violet 15, 17, 49, C.I. I. Acid Blue 1, 7, 9, 15, 22, 23, 25, 40, 41, 43, 62, 78, 83, 90, 93, 100, 103, 104, 112, 113, 158, C.I. I. Acid Green 3, 9, 16, 25, 27, C.I. I. Acid dyes such as Acid Orange 56, C.I. I. Food dyes such as Food Yellow 3, Malachite Green (C.I. 42000), Victoria Blue FB (C.I. 44545), Methyl Violet FN (C.I. 42535), Rhodamine F4G (C.I. 45160), And basic dyes such as rhodamine 6GCP (C.I. 45160).
These can be used alone or in combination of two or more, and the amount used is 10 to 60% by weight based on the total amount of the ink composition used when the colorant is a dye alone.
In addition, the usage-amount at the time of mixing and using the said dye, an organic pigment, an inorganic pigment, a processed pigment etc. is 10 to 60 weight% with respect to the used ink composition as a coloring agent component whole quantity.

Examples of commercially available ethyl cellulose include etose 4, 7, 10, 14, 20, 45, 70, 100, 200, 300 (Dow Chemical Japan Co., Ltd.), AQUALON N50, N100, N200, N300 (manufactured by Ashland, USA), and the like.
Further, as described above, it is also possible to use particles obtained by finely dispersing a pigment in ethyl cellulose in advance. Specific examples include: Microlith Yellow 4G-A, Yellow MX-A, Yellow 2R-A, Brown 5R-A, Scarlet RA, Red 2C-A, Red 3R-A, Magenta
2B-A, Violet B-A, Blue 4G-A, Green G-A, Black C-A, White R-A (pigment finely dispersed in ethyl cellulose resin, manufactured by BASF, Germany), etc. Is mentioned.
Since ethyl cellulose has a structure in which the hydroxyl group of cellulose is substituted with an ethyl group, the hydrogen bonding portion that is the strongest binding force for crystallization of cellulose is reduced, and the ethyl group of the substituent has an affinity for an organic solvent. It is high and the SP value is 10.3, which is the smallest among cellulose derivatives. For this reason, the solubility in organic solvents and the solvent retention power are the highest among cellulose derivatives. In the present invention, an SP solvent having an SP value of 8.0 or more and 9.5 or less and containing an oxypropylene group in the molecule, When used in combination with an organic solvent having an SP value of 8.0 or more and 9.5 or less and containing a hydroxyl group in the molecule and not containing an oxypropylene group, there is no ink leakage, a light writing taste is obtained, and there is no blurring of handwriting. An oil-based ink composition could be obtained.
In addition, when ethyl cellulose is added to the ink as a particle obtained by finely dispersing a pigment in ethyl cellulose in advance, the pigment supports the ethyl cellulose in the ink and gives the ink a greater shear thinning viscosity. In this way, an extremely light writing taste can be obtained, and since ethyl cellulose helps to disperse the pigment, the sedimentation of the pigment is also suppressed, so that the solid content can be reduced when the pen tip is left to stand downward. Deterioration of writing quality and blurring of handwriting due to an increase in the amount of ink hardly occur.
The amount of ethyl cellulose used is 1% or more of ethyl cellulose with respect to the whole ink, and if the amount of pigment is 4.5 times or more that of ethyl cellulose, the viscosity of the ink at the time of standing is increased, and a large shear thinning is achieved. It is preferable because it can prevent leakage and provide a very light writing taste, and ethyl cellulose can sufficiently assist the dispersion of the pigment, so that the pigment dispersibility and the pigment dispersion stability are also improved. As a specific viscosity, at a shear rate of 0.01 s ^-1 close to standing, the ink is in a state where it is difficult to flow by setting it to 500,000 mPa · s or more, more preferably by setting it to 1000000 mPa · s or more, Since the ink hardly flows, it is not necessary to consider the influence of gravity, and when the pen tip is left facing down, the writing quality is deteriorated and the handwriting is not smooth due to the increased solid content. It becomes difficult to occur. In addition, when the amount of ethyl cellulose in the ink is more than 10% by weight, the amount of the thickener is too large with respect to the whole ink, so that other solid materials such as a colorant and a fixing agent are used to dissolve the thickener. The amount of ethyl cellulose added is preferably 10% by weight or less because there is a restriction on the amount of addition of the functional additive and it becomes difficult to balance the overall quality characteristics of the ballpoint pen.

As an organic solvent having an SP value of 8.0 or more and 9.5 or less and containing an oxypropylene group in the molecule, propylene glycol normal propyl ether (SP value 9.4), propylene glycol normal butyl ether (SP value 8.9) , Propylene glycol diacetate (SP value 8.9), dipropylene glycol normal methyl ether (SP value 9.1), dipropylene glycol normal propyl ether (SP value 8.6), dipropylene glycol normal butyl ether (SP value 8) .2), dipropylene glycol dimethyl ether (SP value 8.2), dipropylene glycol methyl ether acetate (SP value 8.6), tripropylene glycol normal methyl ether (SP value 9.1), tripropylene glycol normal butyl Ether (SP value 8.1), and the like.
In solvent molecules containing oxypropylene groups, the adsorption probability of oxypropylene groups having affinity for both hydrophilic groups and hydrophobic skeletons such as hydroxyl groups of ethyl cellulose is the highest, so even if hydroxyl groups are contained in the solvent molecules Even if it is not contained, the oxypropylene group may have a function of temporarily protecting a hydrophilic group such as hydrogen bond of ethyl cellulose and a hydrophobic skeleton.
The blending amount is not particularly limited, but if it is 1% by weight or less in the ink, an effect sufficient to improve the solubility of ethyl cellulose cannot be obtained, so addition of 1% by weight or more is desirable.

An organic solvent having a SP value of 8.0 or more and 9.5 or less and containing a hydroxyl group in the molecule and not containing an oxypropylene group is ethylene glycol-2-ethylhexyl ether (SP value 9.0, dissolved in water at 20 ° C.). 0.2%, containing oxyethylene groups in the molecule), diethylene glycol-2-ethylhexyl ether (SP value 9.2, solubility in water at 20 ° C. 0.3%, oxyethylene groups in the molecule) Containing), ethylene glycol isopropyl ether (SP value 9.2, infinite solubility in water at 20 ° C., containing an oxyethylene group in the molecule), diethylene glycol monobutyl ether (SP value 9.5, at 20 ° C. Infinity in water, containing oxyethylene group in the molecule), diethylene glycol isobutyl ether (SP value) .7, infinite solubility in water at 20 ° C., containing an oxyethylene group in the molecule), and the like as specific examples of organic solvents not containing an oxyethylene group in the molecule, such as 2-ethylhexanol (SP Value 9.5, solubility in water at 20 ° C 0.1%, no oxyethylene group in the molecule), 3-methoxy-3-methylbutanol (SP value 9.3, water solubility at 20 ° C) SP value such as infinite solubility, no oxyethylene group in the molecule), lauryl alcohol (SP value 8.1) and trimethyl-3,5,5-hexanol (SP value 8.4) is 8.0. A monovalent alkyl alcohol having 9 or more carbon atoms and having a carbon number of 9.5 or less (both having a solubility in water of 0.1% or less and containing no oxyethylene group in the molecule) has an oxyethylene group in the molecule. Do not contain It is given as specific examples of the organic solvent.
As described above, the organic solvent containing a hydroxyl group in the molecule and not containing an oxypropylene group is infinitely miscible with water, and even if moisture is absorbed in the ink in a high humidity environment, Since each component is uniformly mixed, water does not exist as a separated layer in the ink, and partial insolubilization of ethyl cellulose does not occur, which is preferable. In addition, if the structure does not contain an oxyethylene group in the molecule, it has a higher penetrating power to the solute and there is little change in solubility depending on the temperature change. It is preferable because the solid matter settles when it is left standing with the nib facing downward, and the writing quality does not deteriorate due to the increase of the solid content in the nib.
The blending amount is not particularly limited, but if it is 1% by weight or less in the ink, an effect sufficient to improve the solubility of ethyl cellulose cannot be obtained, so addition of 1% by weight or more is desirable.
The total of the organic solvent containing an oxypropylene group in the molecule and the organic solvent containing a hydroxyl group in the molecule and not containing an oxypropylene group in the ink is more preferably 10% by weight or more based on the total solvent in the ink. When the content is 20% by weight or more, the solubility of ethyl cellulose is improved, so that ethyl cellulose can be efficiently dissolved in a shorter time.
Moreover, if the compounding ratio of the organic solvent containing an oxypropylene group and the organic solvent containing a hydroxyl group and not containing an oxypropylene group is 50: 1 to 1: 1, the organic compound containing a hydroxyl group and not containing an oxypropylene group This is preferable because sufficient balance between the solvent and the effect of protecting the ethyl cellulose of the organic solvent containing an oxypropylene group in the molecule is good, and the ethyl cellulose is more easily dissolved.

In addition to the organic solvent, a conventionally known organic solvent for ballpoint pens may be used in combination. In consideration of the drying property of the nib, the boiling point is desirably 150 ° C. or higher. When a product having a boiling point of 150 ° C. or lower is used, the product shape can be used if it is a cap type. For example, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, diethylene glycol monobenzyl glycol, propylene Glycol ether solvents such as glycol normal butyl ether, propylene glycol monophenyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monophenyl ether, tripropylene glycol monophenyl ether, ethylene glycol, diethylene glycol, pro Glycol solvents such as lenglycol, dipropylene glycol, hexylene glycol, glycerin, polyethylene glycol, ester solvents such as 2-ethylhexyl acetate, isobutyl isobutyrate, ethyl lactate, butyl lactate, benzyl alcohol, β- Alcohol solvents such as phenylethyl alcohol, α-methylbenzyl alcohol, lauryl alcohol, tridecyl alcohol, isododecyl alcohol, isotridodecyl alcohol, and the like can be used.
These may be used singly or as a mixture of two or more thereof. The blending amount of the above solvent is an organic solvent having an SP value of 8.0 or more and 9.5 or less and containing an oxypropylene group in the molecule. And the total solvent amount of the organic solvent including the SP value of 8.0 or more and 9.5 or less and containing a hydroxyl group in the molecule and not containing an oxypropylene group is 20 to 90% by weight, preferably 35% based on the total amount of the ink. ~ 75 wt%.
In addition, an organic solvent having an SP value of 8.0 or more and 9.5 or less and containing an oxypropylene group in the molecule, and an SP value of 8.0 or more and 9.5 or less containing a hydroxyl group in the molecule and containing an oxypropylene group. If the total amount of organic solvents not contained is 10% by weight or more, more preferably 20% by weight or more of the total solvent, the organic solvent containing oxypropylene groups and the hydroxyl group- containing oxy The amount of organic solvent that does not contain a propylene group becomes sufficient, hydrophilic groups such as hydrogen bonds of ethyl cellulose and hydrophobic skeletons are sufficiently protected, and the function of a solvent that makes hydrogen bonds amorphous can be obtained more sufficiently. This is preferable because the solubility of ethyl cellulose is further improved.

Further, resins usually used as a fixing agent or a dispersing agent in a ballpoint pen ink composition, for example, ketone resins, sulfoamide resins, acrylic resins, maleic resins, copolymers of styrene and maleic esters, styrene and acrylic acid or Copolymer with ester, ester gum, xylene resin, urea resin, polyamide resin, alkyd resin, phenol resin, alkylphenol resin, terpene phenol resin, rosin resin and its hydrogenated compound, polyvinyl butyral, polyvinyl acetal, polyvinyl alkyl Ether, polyvinyl pyrrolidone, polyethylene oxide and the like can be used in combination. These resins may be used alone or in combination of two or more, and the blending amount thereof is in the range of 0.1 to 15% by weight with respect to the total amount of the ink composition.
These resins have the effects of adjusting the viscosity of the ink composition and improving the adhesion and water resistance.

In addition, auxiliary agents commonly used in ink compositions such as preservatives, rust preventives, antifoaming agents, lubricants, dispersants, anti-scratch agents, leak-proofing agents, and surfactants are added as necessary. Also good.
For example, anionic, cationic, nonionic, amphoteric surfactants, and polymer resins can be used supplementarily in order to improve the dispersibility of the pigment. Specifically, higher fatty acid, higher alcohol sulfate ester salt, fatty acid sulfate ester salt, alkylallyl sulfonic acid, phosphate ester, polyoxyalkylene alkyl ether, polyoxyalkylene alkyl phenyl ether, sorbitan fatty acid ester, etc. Anionic, nonionic, cationic surfactants, resins and oligomers for pigment dispersion such as polyvinyl butyral resin, polyvinyl pyrrolidone resin, polyacrylic ester resin, polymethacrylic ester resin, styrene-acrylic acid copolymer resin Is mentioned.
Also, lubricants such as phosphate ester compounds, unsaturated fatty acids, hardened castor oil, rust preventives such as benzotriazole, metal salt, phosphate ester compounds, preservatives such as isothiazolone and oxazolidine compounds, Antifoaming agents such as silicon-based, mineral oil, fluorine-based compounds, wetting agents such as glycerin, sorbitan-based, polysaccharides, urea, ethyleneurea or derivatives thereof, acetylene glycol, acetylene alcohol, and silicon-based surfactants It is also possible to use a conventional well-known additive for ink such as leveling property imparting agents and antifreezing agents.
Moreover, it is possible to use the general method generally used for disperse | distributing a pigment. For example, a pigment, a solvent, and a dispersing agent are mixed and uniformly stirred with a propeller stirrer or the like, and then the pigment is dispersed with a disperser. A disperser 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 ink water or organic solvent and the pigment concentration.

In the present invention, it is usually possible to disperse the pigment by a general method. For example, a pigment, a solvent, and a dispersing agent are mixed and uniformly stirred with a propeller stirrer or the like, and then the pigment is dispersed with a disperser. A disperser such as a roll mill, a ball mill, a sand mill, a bead mill, or a homogenizer is appropriately selected depending on the solvent amount of the oil-based ink composition and the pigment concentration.
In order to produce an oil-based ink composition, the pigment dispersed above and other components such as a viscosity adjusting resin, a solvent, a fixing agent, a lubricant, and other additives are mixed, and a dyno mill, a ball mill, a roll mill, an attritor are mixed. It can be obtained by dissolving and mixing until uniform with a stirrer such as a sand grinder, turbo mixer, lab mixer, homomixer, etc. The obtained oil-based ink composition may be filtered or centrifuged to remove coarse particles and insoluble components.
In addition, ethylcellulose is first dissolved in an organic solvent having an SP value of 8.0 or more and 9.5 or less and containing an oxypropylene group in the molecule, or at least simultaneously as a mixed solvent with a solvent in other ink. Thus, the organic solvent containing an oxypropylene group can temporarily protect the hydrophilic group such as hydrogen bond of ethyl cellulose and the hydrophobic skeleton.

(Example 1)
Printex G (carbon black, manufactured by Evonik Degussa Japan Co., Ltd.)
19.90 parts by weight Microlith BLACK C-A (processed pigment in which pigment is finely dispersed in an ethylcellulose carrier, the ratio of pigment to ethylcellulose is 6: 4, manufactured by BASF, Germany)
14.20 parts by weight ESREC BL-1 (polyvinyl butyral, dispersant, manufactured by Sekisui Chemical Co., Ltd.)
2.80 parts by weight Hilac 901 (ketone resin, manufactured by Hitachi Chemical Co., Ltd.) 5.00 parts by weight PVP K-90 (polyvinylpyrrolidone, manufactured by ISP Japan Co., Ltd.) 0.40 parts by weight 3-methoxy-3 -Methyl-1-butanol (SP value 9.3, organic solvent containing a hydroxyl group in the molecule and not containing oxypropylene group and oxyethylene group) 10.00 parts by weight tripropylene glycol monobutyl ether (SP value 8.1) , An organic solvent containing an oxypropylene group in the molecule) 18.10 parts by weight hexylene glycol (SP value 10.5, an organic solvent containing a hydroxyl group in the molecule and not containing an oxypropylene group and an oxyethylene group) .3 parts by weight diethylene glycol monomethyl ether (SP value 10.7, containing hydroxyl group in the molecule, 7.30 parts by weight phenyl glycol (SP value 11.5, containing hydroxyl group in the molecule, containing no oxypropylene group and containing an oxyethylene group) Solvent) 5.00 parts by weight Printex G, Eslek BL-1 and all solvent components in the above components were heated and stirred and then dispersed for 1 hour in a bead mill to obtain a black pigment base. The remaining material was added to the black pigment base, and the mixture was heated and stirred for 1 hour, and the viscosity at 25 ° C. at a shear rate of 0.01 sec ⁻¹ was 2008000 mPa · s, and the viscosity at a shear rate of 10000 sec ⁻¹ was 1502 mPa · s. An ink was obtained.

(Example 2)
Mitsubishi Carbon Black # 25 (Carbon Black, manufactured by Mitsubishi Chemical Corporation) 23.70 parts by weight Esrek BL-1 (described above) 3.32 parts by weight Etcell 20 (ethyl cellulose, manufactured by Dow Chemical Japan Co., Ltd.) 5.13 Parts by weight Hilac 901 (previously described) 5.00 parts by weight PVP K-90 (previously described) 0.40 parts by weight 3-methoxy-3-methyl-1-butanol (previously described) 39.78 parts by weight propylene glycol monopropyl ether ( SP value 9.4, organic solvent containing an oxypropylene group in the molecule) 15.38 parts by weight to xylene glycol (previously described) 7.30 parts by weight All of Mitsubishi Carbon Black # 25 and ESREC BL-1 in the above components The solvent component was heated and stirred and then dispersed for 1 hour by a bead mill to obtain a black pigment base. The remaining material is added to the black pigment base, and the mixture is heated and stirred for 1 hour. At 25 ° C., the viscosity at a shear rate of 0.01 sec ⁻¹ is 3358000 mPa · s, and the viscosity at a shear rate of 10000 sec ⁻¹ is 831 mPa · s. An ink was obtained.

(Example 3)
Mitsubishi Carbon Black # 25 (previously described) 19.90 parts by weight Microlith BLACK CA (previously described) 14.20 parts by weight Esrek BL-1 (previously described) 2.80 parts by weight Hilac 901 (previously described) 5.00 parts by weight PVP K-90 (previously described) 0.40 parts by weight 3-methoxy-3-methyl-1-butanol (previously described) 28.30 parts by weight tripropylene glycol monobutyl ether (previously described) 29.4 parts by weight Mitsubishi Carbon in the above components Black # 25, Eslek BL-1 and all solvent components were heated and stirred, and then dispersed for 1 hour in a bead mill to obtain a black pigment base. The remaining material is added to the black pigment base, and the mixture is heated and stirred for 1 hour. At 25 ° C., the viscosity at a shear rate of 0.01 sec ⁻¹ is 1102000 mPa · s, and the viscosity at a shear rate of 10000 sec ⁻¹ is 859 mPa · s. An ink was obtained.

Example 4
Mitsubishi Carbon Black # 25 (previously described) 19.90 parts by weight Microlith BLACK CA (previously described) 14.20 parts by weight Esrek BL-1 (previously described) 2.80 parts by weight Hilac 901 (previously described) 5.00 parts by weight PVP K-90 (previously described) 0.40 parts by weight 3-methoxy-3-methyl-1-butanol (previously described) 1.00 parts by weight tripropylene glycol monobutyl ether (previously described) 50.00 parts by weight phenyl glycol (previously described) 6 .70 parts by weight Mitsubishi Carbon Black # 25, Eslek BL-1 and all the solvent components in the above components were heated and stirred and then dispersed for 1 hour in a bead mill to obtain a black pigment base. The remaining material is added to the black pigment base, and the mixture is heated and stirred for 1 hour, and the viscosity at a shear rate of 0.01 sec ⁻¹ at 125 ° C. and a viscosity of 1002 mPa · s at a shear rate of 10000 sec ⁻¹ is 25 ° C. An ink was obtained.

(Example 5)
Mitsubishi Carbon Black # 25 (previously described) 21.10 parts by weight Etcell 4 (ethyl cellulose, manufactured by Dow Chemical Japan Co., Ltd.) 10.00 parts by weight Esrek BL-1 (previously described) 2.80 parts by weight PVP K-90 (previously described) ) 0.40 parts by weight 3-methoxy-3-methyl-1-butanol (previously described) 16.20 parts by weight tripropylene glycol monobutyl ether (previously described) 35.00 parts by weight diethylene glycol monomethyl ether (previously described) 15.00 parts by weight Mitsubishi Carbon Black # 25, Eslek BL-1 and all solvent components in the components were heated and stirred and then dispersed for 1 hour in a bead mill to obtain a black pigment base. Adding the remaining materials in the black pigment-based, 1 hour heating and stirring, a viscosity of 560700mPa · s at a shear rate of 0.01 sec ^-1 at 25 ° C., black viscosity 12540mPa · s at a shear rate of 10000 sec ^-1 An ink was obtained.

(Example 6)
LIONOL BLUE E (blue pigment, Pigment blue 15: 6, manufactured by Toyo Ink Co., Ltd.) 18.02 parts by weight Microlith Blue 4G-A (Processed pigment in which pigment is finely dispersed in ethyl cellulose carrier, ratio of pigment to ethyl cellulose) 6: 4, BASF, Germany)
14.20 parts by weight Solsperse 12000 (pigment derivative, manufactured by Lubrizol, USA)
1.78 parts by weight of Solsperse 20000 (dispersant, Lubrizol, USA)
7.13 parts by weight SK resin (ketone resin, (ketone resin, manufactured by Evonik Degussa Japan Co., Ltd.)
10.56 parts by weight PVP K-90 (previously described) 0.40 parts by weight diethylene glycol monobutyl ether (SP value 9.5, containing an hydroxyl group in the molecule, not containing an isopropylene group and containing an oxyethylene group) 7.13 parts by weight Dipropylene glycol normal butyl ether (SP value 8.2, organic solvent containing oxypropylene group in the molecule) 17.10 parts by weight phenyl glycol (previously described) 23.68 parts by weight LIONOL in the above components BLUE E, Solsperse 12000, Solsperse 20000 and all solvent components were heated and stirred and dispersed for 1 hour by a bead mill to obtain a blue pigment base. The remaining material is added to the blue pigment base, and the mixture is heated and stirred for 1 hour. At 25 ° C., the viscosity at a shear rate of 0.01 sec ⁻¹ is 100000 mpa · s, and the viscosity at a shear rate of 10000 sec ⁻¹ is 2940 mPa · s. An ink was obtained.

(Example 7)
FUJI RED # 8800 (red pigment, Pigment red 254, manufactured by Fuji Dye Co., Ltd.) 19.80 parts by weight microrethread 3R-A (processed pigment in which pigment is finely dispersed in ethylcellulose carrier, ratio of pigment to ethylcellulose is 6: 4, BASF, Germany)
14.20 parts by weight ESREC BL-1 (previously described) 4.95 parts by weight SK resin (previously described) 3.30 parts by weight PVP K-90 (previously described) 0.40 parts by weight diethylene glycol isobutyl ether (SP value 8.7, molecule) An organic solvent containing a hydroxyl group and containing no oxypropylene group but containing an oxyethylene group) 36.08 parts by weight tripropylene glycol monobutyl ether (previously described) 2.30 parts by weight hexylene glycol (previously described) 18.98 Part by weight FUJI RED # 8800 of each of the above components, ESREC BL-1, and all solvent components were heated and stirred and dispersed for 1 hour in a bead mill to obtain a red pigment base. Adding the remaining materials to the red pigment base, 1 hour heating and stirring, a viscosity of 566000mPa · s at a shear rate of 0.01 sec ^-1 at 25 ° C., the red viscosity of 1650 MPa · s at a shear rate of 10000 sec ^-1 An ink was obtained.

(Example 8)
Nigrosine Base EX (Oil-soluble dye, manufactured by Orient Chemical Industry Co., Ltd.) 18.00 parts by weight Spiron Violet (Oil-soluble dye, manufactured by Hodogaya Chemical Co., Ltd.) 9.00 parts by weight Spiron Yellow C-2GH (Oil Soluble dye, manufactured by Hodogaya Chemical Co., Ltd.) 4.00 parts by weight Etcel 20 (described above) 3.80 parts by weight Hilac 901 (described above) 8.00 parts by weight PVP K-90 (described above) 0.40 parts by weight ethylene Glycol isopropyl ether (SP value 9.2, an organic solvent containing a hydroxyl group in the molecule and containing no oxypropylene group and containing an oxyethylene group) 11.50 parts by weight propylene glycol normal butyl ether (SP value 8.9, Organic solvent containing oxypropylene group in the molecule) 15.30 parts by weight benzyl alcohol (SP value 12.1, in the molecule Containing an acid group, an organic solvent not containing oxypropylene group and oxyethylene group) 30.00 parts by weight of heated and stirred mixture of the above components, 25 - viscosity at a shear rate of 0.01sec ^-1 34000mPa at ° C. s A black ink having a viscosity of 438 mPa · s at a shear rate of 10,000 sec ⁻¹ was obtained.

Example 9
Mitsubishi Carbon Black # 25 (previously described) 19.90 parts by weight Microlith BLACK CA (previously described) 14.20 parts by weight Esrek BL-1 (previously described) 2.80 parts by weight Hilac 901 (previously described) 5.00 parts by weight PVP K-90 (previously described) 0.40 parts by weight ethylene glycol isopropyl ether (previously described) 1.00 parts by weight tripropylene glycol monobutyl ether (previously described) 5.00 parts by weight diethylene glycol monomethyl ether (previously described) 45.00 parts by weight phenyl glycol (Above) 6.70 parts by weight Mitsubishi Carbon Black # 25, Eslek BL-1 and all the solvent components in the above components were heated and stirred and then dispersed for 1 hour in a bead mill to obtain a black pigment base. The remaining material was added to the black pigment base, and the mixture was heated and stirred for 1 hour, and the viscosity at a shear rate of 0.01 sec ⁻¹ at 25 ° C. was 740000 mPa · s, and the viscosity at a shear rate of 10000 sec ⁻¹ was 430 mPa · s. An ink was obtained.

(Example 10)
Mitsubishi Carbon Black # 25 (mentioned above) 21.10 parts by weight AQUALON N200 (ethyl cellulose, manufactured by Ashland, USA)
0.50 parts by weight Eslek BL-1 (previously described) 2.80 parts by weight Hilac 901 (previously described) 5.00 parts by weight PVP K-90 (previously described) 0.40 parts by weight ethylene glycol isopropyl ether (previously described) 4.00 Parts by weight dipropylene glycol dibutyl ether (SP value 8.2, organic solvent containing an oxypropylene group in the molecule) 15.00 parts by weight diethylene glycol monomethyl ether (previously described) 45.00 parts by weight phenyl glycol (previously described) 6.70 Part by weight Mitsubishi Carbon Black # 25, Eslek BL-1 and all the solvent components in the above components were heated and stirred and then dispersed for 1 hour in a bead mill to obtain a black pigment base. Adding the remaining materials in the black pigment-based, 1 hour heating and stirring, a viscosity of 7800mPa · s at a shear rate of 0.01 sec ^-1 at 25 ° C., black viscosity of 253mPa · s at a shear rate of 10000 sec ^-1 An ink was obtained.

(Example 11)
Mitsubishi Carbon Black # 25 (mentioned above) 21.10 parts by weight AQUALON N200 (ethyl cellulose, manufactured by Ashland, USA)
0.50 parts by weight Eslek BL-1 (previously described) 2.80 parts by weight Hilac 901 (previously described) 5.00 parts by weight PVP K-90 (previously described) 0.40 parts by weight lauryl alcohol (SP value 8.1, molecule) Organic solvent containing a hydroxyl group and not containing an isopropylene group or an oxyethylene group) 1.00 parts by weight Tripropylene glycol monobutyl ether (previously described) 38.00 parts by weight diethylene glycol monomethyl ether (previously described) 25.00 parts by weight phenyl Glycol (described above) 6.70 parts by weight Mitsubishi Carbon Black # 25, Eslek BL-1 and all the solvent components in the above components were heated and stirred and then dispersed in a bead mill for 1 hour to obtain a black pigment base. Adding the remaining materials in the black pigment-based, 1 hour heating and stirring, a viscosity of 12500mPa · s at a shear rate of 0.01 sec ^-1 at 25 ° C., black viscosity of 783mPa · s at a shear rate of 10000 sec ^-1 An ink was obtained.

(Example 12)
Printex G (previously described) 22.90 parts by weight ESREC BL-1 (previously described) 3.20 parts by weight etcell 200 (ethyl cellulose, manufactured by Dow Chemical Japan Co., Ltd.) 3.00 parts by weight Hilac 901 (previously described) 4.50 Parts by weight PVP K-90 (previously described) 0.40 parts by weight ethylene glycol-2-ethylhexyl ether (SP value 9, organic solvent containing a hydroxyl group in the molecule and no oxypropylene group but an oxyethylene group) 38.40 parts by weight Tripropylene glycol normal butyl ether (previously described) 20.50 parts by weight phenyl glycol (previously described) 7.10 parts by weight In the ingredients, Printex G, S-Rec BL-1, and all the solvent components were heated and stirred, and 1 in a bead mill. Dispersion with time gave a black pigment base. The remaining material was added to the black pigment base, and the mixture was heated and stirred for 1 hour. At 25 ° C., the viscosity at a shear rate of 0.01 sec ⁻¹ was 1208750 mPa · s, and the viscosity at a shear rate of 10000 sec ⁻¹ was 402 mPa · s. An ink was obtained.

(Example 13)
Printex G (previously described) 19.90 parts by weight Microlith BLACK C-A (previously described) 14.20 parts by weight Esrek BL-1 (previously described) 2.80 parts by weight Hilac 901 (previously described) 5.00 parts by weight PVP K- 90 (previously described) 0.40 parts by weight ethylene glycol-2-ethylhexyl ether (previously described) 5.00 parts by weight tripropylene glycol monobutyl ether (previously described) 27.10 parts by weight hexylene glycol (previously described) 17.30 parts by weight diethylene glycol monomethyl Ether (previously described) 11.30 parts by weight Phenylglycol (previously described) 5.00 parts by weight After stirring and heating, Printex G, Eslek BL-1 and all solvent components in the above components were dispersed in a bead mill for 1 hour. A pigment base was obtained. The remaining material is added to the black pigment base, and the mixture is heated and stirred for 1 hour. At 25 ° C., the viscosity at a shear rate of 0.01 sec ⁻¹ is 2980030 mPa · s, and the viscosity at a shear rate of 10000 sec ⁻¹ is 1890 mPa · s. An ink was obtained.

(Example 14)
Printex G (previously described) 19.90 parts by weight Microlith BLACK C-A (previously described) 14.20 parts by weight Esrek BL-1 (previously described) 2.80 parts by weight Hilac 901 (previously described) 5.00 parts by weight PVP K- 90 (described above) 0.40 parts by weight diethylene glycol-2-ethylhexyl ether (SP value 9.3, organic solvent containing a hydroxyl group in the molecule and no oxypropylene group but an oxyethylene group)
1.00 parts by weight Tripropylene glycol monobutyl ether (previously described) 27.10 parts by weight hexylene glycol (previously described) 17.3 parts by weight diethylene glycol monomethyl ether (previously described) 7.30 parts by weight phenyl glycol (previously described) 5.00 parts by weight Printex G, Eslek BL-1 and all solvent components in the above components were heated and stirred and then dispersed for 1 hour in a bead mill to obtain a black pigment base. The remaining material was added to the black pigment base, and the mixture was heated and stirred for 1 hour, and the viscosity at a shear rate of 0.01 sec ⁻¹ at 25 ° C. was 3547500 mPa · s, and the viscosity at a shear rate of 10000 sec ⁻¹ was 2309 mPa · s. An ink was obtained.

(Example 15)
Printex G (previously described) 19.90 parts by weight Microlith BLACK C-A (previously described) 14.20 parts by weight Esrek BL-1 (previously described) 2.80 parts by weight Hilac 901 (previously described) 5.00 parts by weight PVP K- 90 (previously described) 0.40 parts by weight ethylene glycol-2-ethylhexyl ether (previously described) 10.00 parts by weight tripropylene glycol monobutyl ether (previously described) 10.00 parts by weight hexylene glycol (previously described) 17.30 parts by weight diethylene glycol monomethyl Ether (previously described) 13.40 parts by weight Phenyl glycol (previously described) 15.00 parts by weight The above-described components of Printex G, Eslek BL-1, and all solvent components were heated and stirred, and then dispersed in a bead mill for 1 hour. A pigment base was obtained. The remaining material was added to the black pigment base, and the mixture was heated and stirred for 1 hour. At 25 ° C., the viscosity at a shear rate of 0.01 sec ⁻¹ was 1907500 mPa · s, and the viscosity at a shear rate of 10000 sec ⁻¹ was 1309 mPa · s. An ink was obtained.

(Comparative Example 1)
Similarly, the viscosity at 250 ° C. and a shear rate of 0.01 sec ⁻¹ at 25 ° C. was changed to 25020 mPa · s except that etose 20 in Example 2 was replaced with Metrolse SM-1500 (methyl cellulose, manufactured by Shin-Etsu Chemical Co., Ltd.). A black ink having a shear rate of 10,000 sec ^{−1 and} a viscosity of 15500 mPa · s was obtained.

(Comparative Example 2)
Similarly, the viscosity at a shear rate of 0.01 sec ⁻¹ at 25 ° C. was 98000 mPa · s, except that ethcel 20 of Example 2 was replaced with KLUCEL-H (hydroxypropylcellulose, manufactured by Ashland, USA). A black ink having a viscosity at a shear rate of 10,000 sec ⁻¹ of 2835 mPa · s was obtained.

(Comparative Example 3)
In the same manner as in Example 1, except that 3-methoxy-3-methyl-1-butanol was replaced with diethylene glycol diethyl ether (SP value 8.6, organic solvent containing no hydroxyl group in the molecule), shearing was performed at 25 ° C. A black ink having a viscosity of 1622,000 mPa · s at a speed of 0.01 sec ⁻¹ and a viscosity of 1536 mPa · s at a shear rate of 10,000 sec ⁻¹ was obtained.

(Comparative Example 4)
Printex G (previously described) 19.90 parts by weight Microlith BLACK C-A (previously described) 14.20 parts by weight Esrek BL-1 (previously described) 2.80 parts by weight Hilac 901 (previously described) 5.00 parts by weight PVP K- 90 (previously described) 0.40 part by weight dipropylene glycol monobutyl ether (SP value 8.1, organic solvent containing a hydroxyl group in the molecule and an oxypropylene group) 45.40 parts by weight phenyl glycol (previously described) 12.30 Part by weight The Printex G, Eslek BL-1 and all the solvent components in the above components were heated and stirred and dispersed for 1 hour in a bead mill to obtain a black pigment base. As black pigment base was added to the remaining material, the viscosity at a shear rate of 0.01 sec ^-1 at 25 ℃ 1921000mPa · s, the viscosity at a shear rate of 10000 sec ^-1 to obtain a black ink 2506mPa · s.

(Comparative Example 5)
Printex G (previously described) 19.90 parts by weight Microlith BLACK C-A (previously described) 14.20 parts by weight Esrek BL-1 (previously described) 2.80 parts by weight Hilac 901 (previously described) 5.00 parts by weight PVP K- 90 (previously described) 0.40 parts by weight ethylene glycol monohexyl ether (SP value 9.6, organic solvent containing a hydroxyl group in the molecule and containing no oxypropylene group) 28.30 parts by weight Tripropylene glycol monobutyl ether (previously described) 24.4 parts by weight phenylglycol (previously described) 12.30 parts by weight The above-described components of Printex G, Eslek BL-1 and all solvent components are heated and stirred and dispersed in a bead mill for 1 hour. A black pigment base was obtained. As black pigment base was added to the remaining material, the viscosity at a shear rate of 0.01 sec ^-1 at 25 ℃ 2580000mPa · s, the viscosity at a shear rate of 10000 sec ^-1 to obtain a black ink 3935mPa · s.

(Comparative Example 6)
Printex G (previously described) 19.90 parts by weight Microlith BLACK C-A (previously described) 14.20 parts by weight Esrek BL-1 (previously described) 2.80 parts by weight Hilac 901 (previously described) 5.00 parts by weight PVP K- 90 (previously described) 0.40 parts by weight ethylene glycol isopropyl ether (previously described) 45.40 parts by weight phenylglycol (previously described) 12.30 parts by weight Heat-stir the Printex G, Eslek BL-1 and all solvent components in the above components. And dispersed with a bead mill for 1 hour to obtain a black pigment base. Adding the remaining materials to pigment-based its black, the viscosity at a shear rate of 0.01 sec ^-1 at 25 ℃ 890400mPa · s, the viscosity at a shear rate of 10000 sec ^-1 to obtain a black ink 875mPa · s.

(Comparative Example 7)
Printex G (previously described) 19.90 parts by weight Microlith BLACK C-A (previously described) 14.20 parts by weight Esrek BL-1 (previously described) 2.80 parts by weight Hilac 901 (previously described) 5.00 parts by weight PVP K- 90 (previously described) 0.40 parts by weight ethylene glycol isopropyl ether (previously described) 28.30 parts by weight dipropylene glycol monomethyl ether (SP value 9.6, organic solvent containing oxypropylene group in the molecule) 17.10 parts by weight Phenyl glycol (previously described) 12.30 parts by weight Printex G, S-Rec BL-1 and all solvent components in the above components were heated and stirred and dispersed in a bead mill for 1 hour to obtain a black pigment base. As black pigment base was added to the remaining material, the viscosity at a shear rate of 0.01 sec ^-1 at 25 ℃ 7602000mPa · s, the viscosity at a shear rate of 10000 sec ^-1 to obtain a black ink 934mPa · s.

(Comparative Example 8)
Similarly, the shear rate of 0.01 sec at 25 ° C. was used except that tripropylene glycol monobutyl ether of Example 1 was replaced with diethylene glycol diethyl ether (SP value 8.6, organic solvent containing no oxypropylene group in the molecule). viscosity at ^-1 1007800mPa · s, the viscosity at a shear rate of 10000 sec ^-1 to obtain a black ink 890mPa · s.

As described above, 0.3 g of the ink composition obtained in Examples and Comparative Examples was filled into a writing instrument similar to a commercially available oil-based ballpoint pen (ball diameter 0.7 mm, BK70, manufactured by Pentel Co., Ltd.) to obtain a test sample.
However, in Examples 1-7, Example 9, Examples 13-15, and Comparative Examples 2-8, since the ink has high viscosity, the sample is pressurized with a spring, compressed air, or the like. The device was modified so that it could be written in a state where it was, and the pressure was adjusted so that the ink discharge amount was 0.032 ± 0.005 g / 200 m using a spiral writing tester, and the same evaluation was performed.
The writing conditions of the spiral writing tester were a writing speed of 7 cm / sec, a writing angle of 70 °, and a writing load of 150 g. As test items, ink leakage, lightness of writing (writing resistance value), and the presence or absence of blurring of handwriting were evaluated.

  Ink leakage: Each of the ballpoint pen samples filled with the inks of Examples and Comparative Examples was left at room temperature for 1 day with n = 10 in a state where the pen tip was not in contact, and leaked from the pen tip. The ink adhesion length was measured, and the average value of n = 10 was calculated.

Lightness of writing (writing resistance value): n = 5 each ball-point pen sample filled with the inks of the examples and comparative examples, using a Tribo-master (Type: TL201Sa) manufactured by Trinity Lab. The writing resistance value was measured when writing was performed for 15 cm under writing conditions of 7 cm / sec, a writing angle of 70 °, and a writing load of 150 g. In the measurement of the writing resistance value, the data measured for 2 seconds at a measurement frequency of 200 Hz are averaged to calculate the average writing resistance value for the specimen, and n is calculated from the average writing resistance values for the five specimens. = The average value of 5 was calculated and used as the writing resistance value of each example and comparative example.

Scattering of handwriting: Each of the ballpoint pen samples filled with the inks of the examples and the comparative examples is written by n = 10 with a spiral writing tester, and the spot of the handwriting is visually measured, and the average value of n = 10 is calculated. Calculated. The spiral writing conditions employed a measured value of blur in a handwriting of 100 to 200 m when writing 200 m at a writing speed of 7 cm / sec, a writing angle of 70 °, and a load of 150 g.

Stability over time: n = 10 nibs at 80 ° C., 80% and −20 ° C. in the temperature-controlled room with the nibs of the ball-point pen samples filled with the inks of the examples and comparative examples left unloaded. It was stored for 2 weeks in an upward state. Then, it was made to write with a spiral writing tester, the spot part of the handwriting was measured visually, and the average value of n = 10 was calculated. The spiral writing conditions employed a measured value of blur in a handwriting of 100 to 200 m when writing 200 m at a writing speed of 7 cm / sec, a writing angle of 70 °, and a load of 150 g.

  In Examples 1 to 15, since the solvent penetrated into the ethyl cellulose resin particles and was sufficiently dissolved by being sufficiently amorphous, it was possible to obtain a large shear thinning, prevent leakage and light writing. In addition, a good oil-based ink composition that does not cause blurring of handwriting was obtained.

In Examples 6 to 15, the organic solvent containing a hydroxyl group in the molecule and not containing an oxypropylene group temporarily protects a hydrophilic group such as a hydrogen bond of ethyl cellulose and a hydrophobic skeleton, thereby containing a hydroxyl group and an oxypropylene group. The organic solvent that does not contain is bonded to the crystallized hydroxyl group or skeleton of ethyl cellulose at a slow rate, thereby preventing the resin particles from becoming spattered, and the solvent itself has a large penetrating power. After penetrating, the hydrogen bond of ethyl cellulose can be cut off, and it can be sufficiently amorphized to obtain a preferable dissolved state, and there is no ink leakage and smearing of the handwriting, and a light writing oil-based ink composition is obtained.
In particular, in Examples 1 to 10, an organic solvent containing a hydroxyl group in the molecule and not containing an oxypropylene group is infinitely miscible with water. Therefore, even when moisture is absorbed into the ink over time, partial ethyl cellulose It was considered that precipitation due to insolubilization did not occur, and there was no ink leakage and smearing of the handwriting, and an oily ink composition with a lighter writing taste was obtained.
Furthermore, in the oil-based ink compositions for ballpoint pens of Examples 1 to 5, the organic solvent containing a hydroxyl group in the molecule and not containing an oxypropylene group is infinitely mixed with water and does not contain an oxyethylene group in the molecule. Because of its structure, the solubility of ethyl cellulose is less affected by moisture absorption and temperature, it is less likely to cause handwriting blur due to precipitation of ethyl cellulose due to moisture absorption and temperature change, and there is no ink leakage and handwriting blurring. An oil-based ink composition was obtained.

On the other hand, the oil-based ink compositions for ballpoint pens of Comparative Examples 1 to 8 caused handwriting blur due to insufficient solubility of the cellulose derivative.
In Comparative Example 6, ethylene glycol isopropyl ether has an SP value of 8.0 or more and 9.5 or less and contains a hydroxyl group in the molecule, but is not used in combination with an organic solvent containing an oxypropylene group in the molecule. However, sufficient solubility of ethyl cellulose was not obtained. When the solvent contains a hydroxyl group, the hydroxyl group cuts the hydrogen bond of ethyl cellulose on the surface of the resin particle and becomes amorphous, so that the bond part that bundles the polymer chain is released, the polymer chain is released, and the resin particle It is assumed that the surface of the swelled powder could not be completely eliminated without the action of slowing the dissolution rate by the organic solvent containing an oxypropylene group in the molecule. It was.

  As described above in detail, the oil-based ink for ball-point pens of the present invention relates to an oil-based ink composition for ball-point pens that does not leak ink, provides a light writing feel, and does not cause handwriting blurring.

Claims (3)

Organic containing an oxypropylene group in the molecule with a colorant, ethylcellulose, and a solubility parameter (SP value) of 8.0 (cal / cm ³ ) ^{1/2 to} 9.5 (cal / cm ³ ) ^1/2 When the solvent is 1.0% by weight or more in the ink , the solubility parameter (SP value) is 8.0 (cal / cm ³ ) ^1/2 or more and 9.5 (cal / cm ³ ) ^1/2 or less in the molecule. An oil-based ink composition for ballpoint pens containing at least 1.0% by weight or more of an organic solvent containing a hydroxyl group and no oxypropylene group in the ink. An organic solvent having a solubility parameter (SP value) of 8.0 (cal / cm ³ ) ^1/2 or more and 9.5 (cal / cm ³ ) ^1/2 or less and containing a hydroxyl group in the molecule and no oxypropylene group. The ink composition for a ballpoint pen according to claim 1, which is infinitely soluble in water at 20 ° C. An organic solvent having a solubility parameter (SP value) of 8.0 (cal / cm ³ ) ^1/2 or more and 9.5 (cal / cm ³ ) ^1/2 or less and containing a hydroxyl group in the molecule and no oxypropylene group. The oil-based ink composition for ballpoint pens according to claim 1 or 2, which has a structure containing no oxyethylene group in the molecule.