Ink composition for oil-based marking pens

Abstract

To ensure high fixability of an ink composition for oil-based marking pens to an adherend surface and also ensure high cap-off performance under a dry environment.SOLUTION: An ink composition for oil-based marking pens has a solvent containing ethanol, an oil-soluble dye, an oil-soluble resin, a sucrose fatty acid ester component, and a fatty acid glyceride component. In the ink composition for oil-based marking pens, the content of the oil-soluble resin is 5 mass% or more and 15 mass% or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an ink composition for an oil-based marking pen.

Background Art

[0002] An ink composition for an oil-based marking pen is used in various applications because it provides high fixability to the adherend surface compared to water-based ink. Usually, a volatile organic solvent is used in the ink composition for an oil-based marking pen. Therefore, when the cap of the pen is removed and the pen tip is exposed to the air for a long time, the solvent volatilizes and the pen tip dries, resulting in a phenomenon (so-called dry-up) where writing becomes impossible. From the viewpoint of suppressing such dry-up, various compositions of the ink composition for an oil-based marking pen have been studied.

[0003] Patent Document 1 proposes an ink composition for a marking pen containing an alcohol-based solvent and / or an ethylene glycol-based solvent, a dye, and a specific fatty acid derivative that is solid at normal temperature.

[0004] Patent Document 2 proposes an ink composition for an oil-based marking pen containing at least one solvent selected from an alcohol-based solvent and a glycol-based solvent, a dye, and a resin as essential components, and further containing a sucrose fatty acid ester composed of 0 to 40% by weight of sucrose fatty acid monoesters and at least one selected from 100 to 60% by weight of sucrose fatty acid diesters, sucrose fatty acid triesters, and sucrose fatty acid polyesters.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the ink composition for an oil-based marking pen, since a volatile organic solvent is usually used, when the cap of the oil-based marking pen is removed and the pen tip is exposed, the drying of the pen tip tends to progress. Therefore, in the case of an oil-based marking pen, when writing is performed after leaving the pen tip exposed for a long time, streaks are likely to occur in the handwriting. That is, it is difficult to ensure high cap-off property. On the other hand, the ink composition for an oil-based marking pen is required to have high fixing property to the adherend surface. However, there is a trade-off relationship between the cap-off property and the fixing property of the ink composition for an oil-based marking pen, and it is difficult to achieve both high fixing property and excellent cap-off property.

[0007] In a general atmospheric environment (for example, in an environment of 20 to 25°C and a relative humidity of 50 to 65%), even if high cap-off property can be ensured, in a dry environment (for example, in an environment with a relative humidity of 40% or less), the cap-off property is greatly reduced.

[0008] In this specification, the case where streaks are suppressed when writing after leaving the pen tip of the oil-based marking pen exposed to the atmosphere may be expressed as excellent cap-off property or high cap-off property. Low cap-off property or reduced cap-off property means that streaks are relatively likely to occur when writing after leaving the pen tip exposed to the atmosphere.

Means for Solving the Problems

[0009] In view of the above problems, one aspect of the present invention relates to an ink composition for an oil-based marking pen, which contains a solvent containing ethanol, an oil-soluble dye, an oil-soluble resin, a sucrose fatty acid ester component, and a fatty acid glyceride component, and the content of the oil-soluble resin is 5% by mass or more and 15% by mass or less.

Effects of the Invention

[0010] While ensuring high fixability of the ink composition for oil-based marking pens to the adherend surface, high cap-off property in a dry environment can be ensured.

Mode for Carrying Out the Invention

[0011] Generally, since high fixability to the adherend surface is required for the ink composition for oil-based marking pens, a resin is included. Increasing the content of the resin in the ink composition for oil-based marking pens can enhance the fixability to the adherend surface. On the other hand, in the ink composition for oil-based marking pens, since a volatile organic solvent is usually used, when the oil-based marking pen is left for a long time with the pen tip exposed, the pen tip is likely to dry. When the content of the resin in the ink composition for oil-based marking pens increases, when the pen tip of the oil-based marking pen is left exposed, as the pen tip dries, the resin solidifies to form a strong film. Once such a film is formed, even if writing is done after leaving it, the film is difficult to peel off, so the ink composition for oil-based marking pens is difficult to ooze out from the pen tip, and bleeding of the handwriting becomes prominent or a dry-up that makes writing impossible may occur. From the viewpoint of suppressing dry-up, it is also conceivable to add an additive that forms a thin film on the pen tip to the ink composition for oil-based marking pens. However, even when such an additive is included, in the conventional ink composition for oil-based marking pens, when left for a long time with the pen tip exposed to the atmosphere in a dry environment, a strong film of the additive is formed. Even when writing is done in such a state, since the film is difficult to peel off from the pen tip, the oozing out of the ink composition for oil-based marking pens is inhibited, and writing may become impossible. Thus, it is difficult for the ink composition for oil-based marking pens to achieve both high fixability to the adherend surface and excellent cap-off property.

[0012] In view of the above, the ink composition for an oil-based marking pen according to one aspect of the present invention contains a solvent containing ethanol, an oil-soluble dye, an oil-soluble resin, a sucrose fatty acid ester component, and a fatty acid glyceride component, and the content of the oil-soluble resin is 5% by mass or more and 15% by mass or less.

[0013] According to the above aspect, while ensuring high fixability of the ink composition for an oil-based marking pen to the adherend surface, high cap-off property in a dry environment can be ensured. For example, even when the pen cap is removed for a long time (e.g., 12 hours or more) in a dry environment, by forming a film with an appropriate strength that prevents drying of the pen tip and peels off the film during writing, it is possible to reduce the occurrence of streaks in the handwriting becoming prominent or the inability to write. Note that the dry environment may be an environment where the relative humidity is, for example, 40% or less. Also, at such a relative humidity, when conditions such as a relatively high temperature (e.g., a temperature of 35°C or higher and 50°C or lower) and / or a relatively high wind speed (e.g., a wind speed of 0.5 m / s or higher) are added, drying tends to proceed more easily. According to the above aspect, even in such a harsh dry environment, high cap-off property can be ensured.

[0014] If the content of the oil-soluble resin in the ink composition for an oil-based marking pen is less than 5% by mass, sufficient fixability to the adherend surface cannot be ensured. When the content of the oil-soluble resin exceeds 15% by mass, although high fixability to the adherend surface can be obtained, when left with the cap removed under dry conditions, drying of the pen tip progresses, the concentration of the resin becomes excessively high, and a strong film of the resin is formed, making it difficult for the ink composition for an oil-based marking pen to ooze out from the pen tip. Therefore, the cap-off property deteriorates, and streaks become prominent or writing becomes impossible when writing after leaving it standing.

[0015] When the ink composition for an oil-based marking pen contains only one of the sucrose fatty acid ester component and the fatty acid glyceride component, in a general atmospheric environment (for example, in an environment of 20 - 25°C and a relative humidity of 50 - 65%), to some extent, the cap-off property can be ensured as in Patent Document 1 or 2. However, under the above-mentioned drying conditions, the cap-off property is significantly reduced.

[0016] Therefore, in order to ensure a high cap-off property under drying conditions, it is important to use a combination of the sucrose fatty acid ester component and the fatty acid glyceride component. In the present invention, by using a combination of the sucrose fatty acid ester component and the fatty acid glyceride component, an appropriate composite film is formed on the surface of the pen tip, which can reduce the volatilization of the solvent. When starting writing, this film can be easily peeled off, and the ink composition for the oil-based marking pen can ooze out onto the adherend surface, effectively reducing the occurrence of streaks in the handwriting. When the content of the oil-soluble resin exceeds 15% by mass, the pen tip dries and the concentration of the resin becomes excessively high, and a strong film of the resin is preferentially formed, making it difficult to exert the effects of the above-mentioned combination of the sucrose fatty acid ester component and the fatty acid glyceride component. That is, only when the content of the oil-soluble resin is 5 - 15% by mass, the effects of the combination of the sucrose fatty acid ester component and the fatty acid glyceride component become apparent, and it becomes possible to ensure a high cap-off property even under severe drying conditions as described above. Even when the content of the oil-soluble resin is 5 - 15% by mass, if only one of the sucrose fatty acid ester component or the fatty acid glyceride component is used, the composition or quality of the film formed on the pen tip is different from the above-mentioned composite film. Therefore, when the oil-based marking pen is left for a long time with the pen tip exposed to the atmosphere under drying conditions, the film of the sucrose fatty acid ester component or the fatty acid glyceride component grows excessively, and a high cap-off property cannot be obtained.

[0017] Hereinafter, the ink composition for an oil-based marking pen will be described in more detail. (Solvent) The solvent only needs to contain ethanol (the first solvent), and may also contain the first solvent and other solvents (the second solvent).

[0018] The proportion of ethanol in the solvent is, for example, 50% by mass or more. From the perspective of ensuring high quick-drying property while ensuring high cap-off property in a dry environment, the proportion of ethanol is preferably 70% by mass or more, more preferably 75% by mass or more or 80% by mass or more. The proportion of ethanol is 100% by mass or less. Ethanol alone may be used as the solvent.

[0019] Examples of the second solvent include alcohols other than ethanol (including phenols), glycol ethers, esters, hydrocarbons, etc. The alcohols may be monohydric alcohols having one hydroxy group or polyhydric alcohols having two or more hydroxy groups. The second solvent may be used alone or in combination of two or more.

[0020] From the perspective of easily controlling the compatibility with the first solvent and the physical properties of the ink composition for an oil-based marking pen, aliphatic alcohols and glycol ethers are preferred as the second solvent. The aliphatic alcohol may be a linear alcohol or a branched-chain alcohol.

[0021] Examples of the monohydric aliphatic alcohol include n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, iso-butyl alcohol, sec-butyl alcohol, t-butyl alcohol, hexyl alcohol, decyl alcohol, etc. The number of carbon atoms of the monohydric aliphatic alcohol is, for example, 3 to 20, and may also be 3 to 12 or 3 to 6.

[0022] Examples of the polyhydric aliphatic alcohol include polyhydroxyalkane, polyalkylene glycol, etc.

[0023] Examples of the polyhydroxyalkane include alkylene glycols (such as ethylene glycol, propylene glycol, propane diol, butane diol, hexane diol, octane diol, etc.), trimethylolpropane, pentaerythritol, etc. The number of carbon atoms of the polyhydroxyalkane is, for example, 1 to 20, and may be 1 to 12 or 2 to 6.

[0024] Examples of the polyalkylene glycol include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, etc. The number of carbon atoms of the oxyalkylene unit contained in the polyalkylene glycol is, for example, 2 to 4, and may be 2 or 3. In the polyalkylene glycol, the repeating number of the oxyalkylene unit is, for example, 2 to 20, and may be 2 to 10 or 2 to 6.

[0025] Examples of the glycol ethers include, for example, monoethers or diethers of glycols, and monoether monoesters of glycols. Examples of the glycols include the polyhydroxyalkanes and polyalkylene glycols exemplified above. Examples of the ether include alkyl ether, aryl ether, aralkyl ether, etc.

[0026] Among the glycol ethers, from the viewpoint of being easily soluble in other components and easily stabilizing the physical properties of the ink composition for an oil-based marking pen, the monoether is preferable. Further, from the viewpoint of having less odor, etc. and high compatibility with the first solvent, the alkyl ether and monoalkyl ether monoester are preferable.

[0027] Examples of the alkyl constituting the alkyl ether include methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, t-butyl, n-pentyl, n-hexyl, etc. The number of carbon atoms of the alkyl is, for example, 1 to 10, and may be 1 to 6, or may be 1 to 4.

[0028] Examples of the acyl group constituting the ester moiety of the monoalkyl ether monoester include aliphatic acyl groups (such as acetyl and propionyl groups), benzoyl group, and the like. Among them, aliphatic acyl groups having 2 to 4 carbon atoms (especially, acetyl group) are preferable.

[0029] Specific examples of the alkyl ether include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol mononormal butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, and the like. Specific examples of the monoalkyl ether monoester include, for example, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monobutyl ether, and the like.

[0030] (Oil-soluble dye) Examples of the oil-soluble dye contained in the ink composition for an oil-based marking pen include, for example, azo dyes, azine dyes (such as nigrosine dyes), triphenylmethane dyes, diphenylmethane dyes, anthraquinone dyes, and the like. Further, basic dyes, acid dyes, direct dyes, disperse dyes, and the like may be used. These dyes may be used alone or in combination of two or more.

[0031] Examples of the oil-soluble dyes include, but are not limited to, OIL COLORS series and VALIFAST series manufactured by Orient Chemical Industries, Ltd., OilColor series manufactured by Chuo Gosei Chemical Co., Ltd., and Spiron series manufactured by Hodogaya Chemical Co., Ltd. Specific examples of the oil-soluble dyes include black dyes (such as Oil Black 2030 manufactured by Chuo Gosei Chemical Co., Ltd., Valifast Black 3810 and Valifast Black 1821 manufactured by Orient Chemical Industries, Ltd.), red dyes (such as Valifast Red 1308 manufactured by Orient Chemical Industries, Ltd., Spiron Red CGH manufactured by Hodogaya Chemical Co., Ltd.), blue dyes (such as Neozapon Blue 807 manufactured by BASF, Spiron Blue CRH manufactured by Hodogaya Chemical Co., Ltd., Oil Blue BA manufactured by Chuo Gosei Chemical Co., Ltd.), yellow dyes (such as Spiron Yellow C-GNH manufactured by Hodogaya Chemical Co., Ltd.), and the like.

[0032] The content of the oil-soluble dye in the ink composition for the oil-based marking pen is, for example, 0.5% by mass or more and 15% by mass or less, and may be 1% by mass or more and 12% by mass or less. When the content of the oil-soluble dye is within such a range, it is easy to control the viscosity of the ink composition for the oil-based marking pen, and in addition to easily ensuring high writing performance, it is advantageous for forming clear handwriting.

[0033] (Oil-soluble resin) The type of the oil-soluble resin is not particularly limited, but a resin that dissolves in a solvent is used. By using the oil-soluble resin, it becomes easy to adjust the viscosity of the ink composition for the oil-based marking pen, so that the writing performance can be improved, and at the same time, the ink composition for the oil-based marking pen can be easily adhered to the adherend surface, so that high fixing property can be obtained.

[0034] The oil-soluble resin is not particularly limited. For example, it includes ketone resins (such as ketone resins and hydrogenated products of ketone resins), phenolic resins (such as alkylphenol resins, phenolic resins, and rosin-modified phenolic resins), xylene resins (such as alkylphenol-modified xylene resins and rosin-modified xylene resins), rosin resins (such as rosin acid resins (such as rosin resins), rosin esters, rosin metal salts, and rosin diols), organic acid-modified vinyl polymers (for example, copolymers of styrene and an organic acid or its acid anhydride (such as acrylic acid, methacrylic acid, maleic acid, and / or maleic anhydride) (such as styrene-acrylic acid copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, etc.) or their salts), acrylic resins (such as polymers containing acrylic ester and / or methacrylic ester as monomer units), and the like.

[0035] The content of the oil-soluble resin in the ink composition for an oil-based marking pen is 5% by mass or more and 15% by mass or less, and may be 5% by mass or more and 10% by mass or less, or 5% by mass or more and 9% by mass or less. When the content of the oil-soluble resin is within such a range, excellent cap-off property in a dry environment can be ensured while ensuring high fixing property to the adherend surface. Also, high writing performance can be ensured. When the content of the oil-soluble resin in the ink composition for an oil-based marking pen exceeds 15% by mass, since the solid content increases, the cap-off property deteriorates, and the fluidity (ink flow) of the ink composition for an oil-based marking pen also tends to decrease. The content of the oil-soluble resin may be 5% by mass or more and 7% by mass or less. In this case, when the oil-based marking pen is left for a long time with the cap off in a dry environment and then the cap is put on again and left for a certain period of time (for example, 12 to 36 hours), the degree of drying at the pen tip can be alleviated.

[0036] (Sucrose fatty acid ester component) Examples of the sucrose fatty acid ester component include sucrose fatty acid esters. The sucrose fatty acid ester may be either a monoester or a polyester. The polyesters include diesters, triesters, tetraesters, pentaesters, hexaesters, heptaesters, and octaesters. The polyester may be an ester of sucrose and one kind of fatty acid, or an ester of sucrose and two or more kinds of fatty acids.

[0037] The sucrose fatty acid ester component may contain one kind of sucrose fatty acid ester, or may contain two or more kinds of sucrose fatty acid esters.

[0038] The sucrose fatty acid ester component may contain, for example, a monoester and a polyester. From the viewpoint of ensuring higher dispersion stability in the ink composition for an oil-based marking pen, it is preferable that the sucrose fatty acid ester component contains at least a polyester (particularly, a diester and / or a triester).

[0039] Examples of the fatty acid constituting the sucrose fatty acid ester include saturated fatty acids and unsaturated fatty acids. Examples of the fatty acid include monovalent aliphatic carboxylic acids having 2 or more carbon atoms. The number of carbon atoms of the aliphatic carboxylic acid is, for example, 2 to 30, may be 2 to 26 or 2 to 22, and may also be 5 to 22 or 12 to 20. The number of carbon-carbon unsaturated bonds contained in the unsaturated fatty acid is, for example, 1 to 3, and may be 1 or 2. The fatty acids also include those having one or more substituents. Examples of the substituent include a hydroxy group, an alkoxy group, a halogen atom, and the like.

[0040] Specific examples of the fatty acid include butanoic acid, pentanoic acid, hexanoic acid, octanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, behenic acid, and montanic acid.

[0041] From the viewpoint of ensuring higher dispersion stability in the ink composition for an oil-based marking pen, the HLB (Hydrophilic-Lipophilic Balance) of the sucrose fatty acid ester is preferably 8 or less, and may be 1 to 8. The sucrose fatty acid ester having such an HLB contains a large amount of polyester.

[0042] The content of the sucrose fatty acid ester in the ink composition for an oil-based marking pen may be 0.05% by mass or more, and may be 0.1% by mass or more. Even if the content of the sucrose fatty acid ester is extremely small, by combining it with the fatty acid glyceride component, high cap-off property can be ensured. From the viewpoint of ensuring higher dispersion stability in the ink composition for an oil-based marking pen, the content of the sucrose fatty acid ester component is preferably 1% by mass or less, and may be 0.5% by mass or less. These lower limit values and upper limit values can be arbitrarily combined.

[0043] (Fatty acid glyceride component) Examples of the fatty acid glyceride component include fatty acid glycerides. Examples of the fatty acid glyceride include at least one selected from the group consisting of fatty acid monoglycerides, fatty acid diglycerides, and fatty acid triglycerides. Among the three hydroxy groups of glycerin, the monoester in which one hydroxy group is esterified with a fatty acid is a fatty acid monoglyceride, and the diester in which each of the two hydroxy groups is esterified with a fatty acid is a fatty acid diglyceride. Fatty acid triglyceride is a triester in which the three hydroxy groups of glycerin are each esterified with a fatty acid.

[0044] As the fatty acid constituting each ester, an aliphatic carboxylic acid having 4 to 30 carbon atoms is preferable. The number of carbon atoms of the aliphatic carboxylic acid may be 10 to 30, may be 10 to 22, or may be 12 to 18. The fatty acid may be a polyvalent fatty acid, but a monovalent fatty acid is preferable. The fatty acid may be either a saturated fatty acid or an unsaturated fatty acid. For the fatty acid, reference can be made to the description and examples of the sucrose fatty acid ester component.

[0045] Each of the fatty acid diglyceride and the fatty acid triglyceride may be an ester of glycerin and one kind of fatty acid, or may be an ester of glycerin and two or more kinds of fatty acids.

[0046] The fatty acid glyceride component may contain one kind of fatty acid glyceride, or may contain two or more kinds of fatty acid glycerides.

[0047] From the viewpoint of ensuring higher dispersion stability in the ink composition for an oil-based marking pen, the fatty acid glyceride component preferably contains at least one selected from the group consisting of fatty acid diglyceride and fatty acid triglyceride, and more preferably contains at least fatty acid triglyceride. From the same viewpoint, in each of the fatty acid diglyceride and the fatty acid triglyceride, it is preferable to use a fatty acid glyceride component containing at least a fatty acid glyceride in which at least one of the three hydroxy groups of glycerin is esterified with a fatty acid having 10 to 30 carbon atoms (preferably 10 to 22 or 12 to 18). Examples of the fatty acid glyceride include CA340.2 and CA210.2 manufactured by MULTICHEM.

[0048] The content of the fatty acid glyceride component in the ink composition for an oil-based marking pen is, for example, 0.1% by mass or more, preferably 0.3% by mass or more, or 0.5% by mass or more. When the content of the fatty acid glyceride component is within such a range, higher cap-off property can be ensured. The content of the fatty acid glyceride component may be 30% by mass or less. From the viewpoint of suppressing the precipitation of the fatty acid glyceride component in the ink composition for an oil-based marking pen and making it easier to fill the ink for an oil-based marking pen into an ink container or a refill, 3.0% by mass or less is preferable, and 2.5% by mass or less is more preferable. These lower limit values and upper limit values can be arbitrarily combined.

[0049] (Silicone oil) The ink composition for an oil-based marking pen may contain silicone oil. In this case, while the solvent volatilizes from the coating film of the ink composition for an oil-based marking pen formed by writing on an adherend surface and the viscosity of the coating film increases, the silicone oil migrates to the surface of the coating film. As a result, the silicone oil bleeds on the surface of the dried coating film and acts as a slipping agent (lubricant). Therefore, even if the coating film of the ink composition for an oil-based marking pen is rubbed, it is slippery and the film is less likely to peel off. Thus, higher fixability of the ink composition for an oil-based marking pen to the adherend surface can be obtained.

[0050] As the silicone oil, at least those having fluidity at room temperature (20 to 30 °C) are used. From the viewpoint of easily ensuring the dispersion stability in the ink composition for an oil-based marking pen, it is preferable to use a modified silicone oil. Examples of the modified silicone oil include polyether-modified silicone oil, amino-modified silicone oil, mercapto-modified silicone oil, carboxy-modified silicone oil, and the like. The ink composition for an oil-based marking pen may contain one kind of silicone oil or two or more kinds of silicone oils. Among these silicone oils, polyether-modified silicone oil is preferable from the viewpoint of easily ensuring high dispersion stability and high rubbing resistance of the handwriting.

[0051] Examples of the polyether-modified silicone oil include polysiloxanes having a polyether structure. The polyether-modified silicone oil may have a polyether structure at the terminal of the molecular chain, may have it in the side chain, or may have it at both the terminal and the side chain.

[0052] The HLB (hydrophile-lipophile balance) of the polyether-modified silicone oil is, for example, 7 or less, and may be 5 or less. The lower limit of the HLB is not particularly limited, but is usually 3 or more.

[0053] From the viewpoint of easily achieving the balance between hydrophilicity and hydrophobicity, the polyether structure is preferably a polyoxyalkylene structure (a repeating structure of oxyalkylene units).

[0054] In the polyoxyalkylene structure, the repeating number of the oxyalkylene group (oxyalkylene unit) is, for example, 2 to 20, may be 2 to 16, or may be 2 to 10 or 2 to 6. The repeating number of the oxyalkylene group is appropriately selected, for example, so that the HLB of the modified silicone oil falls within the above range.

[0055] In the polyoxyalkylene structure, the number of carbon atoms of the alkylene is, for example, 1 to 6, and may be 2 to 6 or 2 to 4. The polyether-modified silicone oil preferably contains at least a polyoxyalkylene structure in which the number of carbon atoms of the alkylene is 2 to 4 (particularly, 2 or 3) as the polyether structure.

[0056] The ink composition for an oil-based marking pen of the present invention contains an oil-soluble resin, a sucrose fatty acid ester component, and a fatty acid glyceride component. In the coating film formed when writing with an oil-based marking pen, as the solvent gradually volatilizes, these components precipitate on the surface to form a film, which may make it difficult for the solvent to further volatilize. This can be said to be the opposite of high cap-off property. The film formed on the surface of the coating film is sticky and may peel off when subjected to a strong impact. For example, when touching the coating film, the film may peel off and the ink composition for an oil-based marking pen in the coating film may adhere. Therefore, in the ink composition for an oil-based marking pen of the present invention, the erasability of the coating film tends to be low.

[0057] When the ink composition for an oil-based marking pen contains a polyether-modified silicone oil containing oxyethylene units, as the solvent volatilizes, the viscosity of the coating film increases, and while the solid content concentration increases from the surface side of the coating film, the polyether-modified silicone oil migrates rapidly to the surface of the coating film. As a result, the polyether-modified silicone oil bleeds relatively early on the surface of the coating film and acts as a slipping agent. Therefore, the coating film (handwriting) is slippery even when rubbed, and it is suppressed that the coating film peels off and adheres when touched, and the drying speed (apparent drying speed) can be shortened. In addition, the fixing property of the coating film (handwriting) to the adherend surface can be further enhanced. The reason why the above polyether-modified silicone oil migrates rapidly to the surface of the coating film is considered to be that the polyether-modified silicone oil contains oxyethylene units, which increases its hydrophilicity and makes it easier to separate from other lipophilic components (such as oil-soluble dyes, oil-soluble resins, fatty acid glycerides (especially oil-soluble resins)) in a state of increased concentration. From the viewpoint that the polyether-modified silicone oil migrates rapidly and easily, it is particularly preferable that the polyether-modified silicone oil contains a repeating structure of oxyethylene units. From the viewpoint of easily introducing a repeating structure of more oxyethylene units into the molecule to enhance hydrophilicity, it is preferable to use a polyether-modified silicone oil having at least a polyether structure (especially a repeating structure of oxyethylene units) in the side chain. In addition, although a polyether-modified silicone oil containing oxyethylene units (especially a repeating structure of oxyethylene units) has higher hydrophilicity than other polyether-modified silicone oils, since the ink composition for an oil-based marking pen contains other lipophilic components in a well-balanced manner, high water resistance of the coating film (handwriting) can be ensured.

[0058] Even when the ink composition for an oil-based marking pen contains a polyether-modified silicone oil containing oxyethylene units, if the content of the oil-soluble resin in the ink composition for an oil-based marking pen is less than 5% by mass, the ratios of the sucrose fatty acid ester component and the fatty acid glyceride component become relatively large, and the coating film itself becomes soft, so it is difficult to increase the drying speed. Therefore, from the viewpoint of ensuring a high drying speed, it is also important that the content of the oil-soluble resin is 5% by mass or more.

[0059] The polyether-modified silicone oil containing oxyethylene units may contain oxyalkylene units other than oxyethylene units. The number of carbon atoms of the alkylene in such oxyalkylene units is, for example, 3 to 6, and 3 or 4 is preferable. The polyether-modified silicone oil containing oxyethylene units and oxypropylene units is easily available.

[0060] The ratio (EO ratio) of the total number of oxyethylene units to the total number of oxyalkylene units in the polyether-modified silicone oil is, for example, 40% or more, and preferably 50% or more. The EO ratio is 100% or less. The total number of oxyalkylene units is the total number of oxyalkylene units contained in one molecule of the polyether-modified silicone oil. The total number of oxyethylene units is the total number of oxyethylene units contained in one molecule of the polyether-modified silicone oil. A polyether-modified silicone oil containing only oxyethylene units as oxyalkylene units (EO ratio = 100%) may be used.

[0061] Examples of the polyether-modified silicone oil having the EO ratio as described above include TSF4440, 4441, 4445, 4446 (EO ratio: 100%), and TSF4452 (total number of oxyethylene units / total number of oxypropylene units (=EO / PO)=50 / 50 (EO ratio 50%)) manufactured by MOMENTIVE Performance Materials. All of these polyether-modified silicone oils are of the side-chain type. From the viewpoint of obtaining a higher slipping effect, it is preferable to use a side-chain type polyether-modified silicone oil.

[0062] The main chain of the polyether-modified silicone oil contains a polysiloxane structure. The polysiloxane structure of the silicone oil usually has an organic group in the side chain in addition to the side chain having a polyether structure. Examples of the organic group include an alkyl group (such as a methyl group) and an aryl group (such as a phenyl group). The polysiloxane structure may be a polyalkylsiloxane structure having an alkyl group in the side chain, or a polyarylsiloxane structure having an aryl group in the side chain. Further, the polysiloxane structure may be a polyalkylarylsiloxane structure having an alkyl group and an aryl group in the side chain. These polysiloxane structures include those in which some of the side chains are hydrogen atoms. From the viewpoint of easily controlling the viscosity of the ink composition for an oil-based marking pen to be low and easily ensuring higher writing properties, the polyether-modified silicone oil preferably has a polyalkylsiloxane structure.

[0063] The content of the silicone oil (or polyether-modified silicone oil) in the ink composition for an oil-based marking pen is, for example, 0.01% by mass or more and 2% by mass or less, and may be 0.05% by mass or more and 2% by mass or less, may be 0.05% by mass or more and 1% by mass or less, or may be 0.1% by mass or more and 1% by mass or less. When the content of the silicone oil is within such a range, in addition to easily ensuring higher fixing property of the ink composition for an oil-based marking pen to the adherend surface, it is easy to ensure higher writing properties.

[0064] The content of the polyether-modified silicone oil containing oxyethylene units in the ink composition for an oil-based marking pen is, for example, 0.01% by mass or more and 2% by mass or less, and may be 0.05% by mass or more and 2% by mass or less. From the viewpoint of enhancing the effect of shortening the drying speed, the content of the polyether-modified silicone oil containing oxyethylene units is preferably 0.1% by mass or more, more preferably 0.3% by mass or more. From the same viewpoint, the content of the polyether-modified silicone oil containing oxyethylene units is preferably 1.5% by mass or less, more preferably 1.2% by mass or less or 1% by mass or less. These lower limit values and upper limit values can be arbitrarily combined.

[0065] (Others) The ink composition for an oil-based marking pen can contain a pigment, an additive, etc. as necessary. The additive is not particularly limited, and examples thereof include known additives added to the ink composition for an oil-based marking pen. Examples of the additive include, but are not limited to, a viscosity modifier, a structure-viscosity imparting agent, a dye solubilizer, a drying property imparting agent, etc.

[0066] The ink composition for an oil-based marking pen can be prepared by mixing the constituent components. In the process of preparation, the mixture may be heated as necessary. The constituent components may be mixed at once, or after mixing some of the constituent components, the remaining constituent components may be added. The order of addition of the constituent components is not particularly limited. For example, sucrose fatty acid ester and fatty acid glyceride are dissolved in a solvent, and the resulting solution and an oil-soluble resin are mixed under heating (for example, 45 to 50 °C), and an oil-soluble dye, a silicone oil (for example, a side-chain type polyether-modified silicone oil) as necessary, a pigment, and / or an additive are added and further mixed, and then cooled (for example, cooled to a temperature of 30 °C or lower) to prepare the ink composition for an oil-based marking pen. The silicone oil (for example, a side-chain type polyether-modified silicone oil) may be added and mixed after cooling, and may be added and mixed both before and after cooling as necessary.

[0067] As described above, the ink composition for an oil-based marking pen is excellent in cap-off property in a dry environment. Therefore, the ink composition for an oil-based marking pen is particularly suitable for use in an oil-based marking pen for applications used in a dry environment.

[0068] Regarding the above dry environment, the relative humidity is, for example, 40% or less, may be 30% or less, and may be 25% or less. Even in such an environment with a low relative humidity, by using the ink composition for an oil-based marking pen of the present invention, it is possible to ensure high cap-off property while ensuring high fixing property to the adherend surface. The lower limit of the relative humidity is not particularly limited. Even when the relative humidity is low, drying of the pen tip can be reduced according to the degree, but for example, it may be 10% or more, and may be 20% or more. These upper limit values and lower limit values can be arbitrarily combined.

[0069] In addition to the above relative humidity, when the temperature is relatively high (for example, 35°C or higher and 50°C or lower), drying of the pen tip when the cap is off becomes remarkable. In the ink composition for an oil-based marking pen of the present invention, drying of the pen tip can be reduced even when used in such a harsh dry environment.

[0070] In addition to the above relative humidity, in an environment where wind is blowing (for example, an environment where the wind speed is 0.5 m / s or more or 0.6 m / s or more), drying of the pen tip when the cap is off becomes even more remarkable. In the ink composition for an oil-based marking pen of the present invention, while ensuring high fixing property to the adherend surface, drying of the pen tip can be reduced even when the oil-based marking pen is used under such a wind speed. The upper limit of the wind speed is not particularly limited. Even when the wind speed is high, drying of the pen tip can be reduced according to the degree, but for example, it may be 1.5 m / s or less, and may be 1 m / s or less. These lower limit values and upper limit values can be arbitrarily combined.

[0071] The ink composition for an oil-based marking pen of the present invention is excellent in cap-off property in a dry environment. In a dry environment, even when the oil-based marking pen is left uncapped for a long time (for example, 12 hours or more, preferably 14 hours or more, more preferably 16 hours or more), drying at the pen tip can be reduced. The time for leaving the pen uncapped in a dry environment may be, for example, 36 hours or less, or 24 hours or less. These lower and upper limits can be arbitrarily combined.

[0072] [Examples] Hereinafter, the present invention will be specifically described based on examples and comparative examples, but the present invention is not limited to the following examples.

[0073] 《Examples 1 to 8 and Comparative Examples 1 to 7》 (1) Preparation of ink composition for oil-based marking pen An ink composition for an oil-based marking pen was prepared with the components and amounts shown in Tables 1A and 1B. More specifically, first, the sucrose fatty acid ester component and the fatty acid glyceride component were dissolved in ethanol as a solvent. The resulting solution was heated to a temperature of 45°C ± 5°C, and an oil-soluble resin was added and stirred to dissolve it. While maintaining the resulting solution at 45°C ± 5°C, an oil-soluble dye and a polyether-modified silicone oil were added to the solution and stirred to dissolve them. In this way, an ink composition for an oil-based marking pen was prepared.

[0074] The following were used as the oil-soluble dye, oil-soluble resin, sucrose fatty acid ester component, fatty acid glyceride component, and polyether-modified silicone oil.

[0075] (i) Oil-soluble dye 1 (manufactured by Hodogaya Chemical Co., Ltd., Spiron Red CGH) (ii) Oil-soluble dye 2 (manufactured by Hodogaya Chemical Co., Ltd., Spiron Yellow C-GNH) (iii) Oil-soluble resin 1 (styrene acrylic resin, manufactured by BASF, Joncryl 682) (iv) Sucrose fatty acid ester component (sucrose fatty acid ester, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., DK ester F-50, HLB 6) (v) Fatty acid glyceride component (fatty acid triglyceride, manufactured by MULTICHEM, CA340.2) (vi) Polyether-modified silicone oil 1 (manufactured by EVONIK, TEGO GLIDE A115, total number of ethylene oxide units / total number of propylene oxide units (= EO / PO) = 0 / 100)

[0076] (2) Preparation of an oil-based marking pen The ink composition for an oil-based marking pen obtained in (1) above was filled into a refill for an oil-based marking pen and set in a container for an oil-based marking pen to prepare an oil-based marking pen.

[0077] (3) Evaluation The following evaluations were performed using the oil-based marking pen prepared in (2) above or the ink composition for an oil-based marking pen prepared in (1) above. For evaluation (a2), Examples 1 to 2, Comparative Examples 1 to 3 and 5 were used.

[0078] (a1) Cap-off property and re-writing property in a dry environment In a thermostatic chamber at 35°C and a relative humidity of 25%, with air at 35°C flowing at a wind speed of 0.7 m ± 0.1 m / s, the cap of the oil-based marking pen was removed and the pen was placed horizontally. The state of the handwriting when writing after 16 hours and 24 hours of leaving it in this state was evaluated (cap-off property). Also, after writing 24 hours after removing the cap, the cap was put on the oil-based marking pen and it was left for 24 hours in an environment at 20°C and a relative humidity of 65%, and the state of the handwriting when writing again (re-writing property) was evaluated. The writing was performed by continuously writing 10 circles with a diameter of 15 mm on a white paper notepad, and the state of the handwriting was evaluated according to the following criteria. 5: No streaks were observed in all 10 circles, or streaks did not occur during the writing of the first circle. 4: Streaks did not occur during the writing of the second circle. 3: No streakiness occurs during the writing of the third or fourth circle. 2: No streakiness occurs during the writing of the fifth to ninth circles. 1: Streakiness is observed in all ten circles.

[0079] Regarding the cap-off property, when the above evaluation is 3 or more after 16 hours from leaving it alone and 2 or more after 24 hours, it is judged as A. When the conditions for A judgment are not met, it is judged as B.

[0080] (a2) Cap-off property in a general atmospheric environment (humid environment) In a constant temperature chamber at 20 °C and 65% relative humidity, the cap of the oil-based marking pen was removed and left in a horizontal position. After 8 hours, 1 day, 2 days, 3 days, 4 days, 7 days, and 11 days from leaving it alone, the state of the handwriting when writing on white paper notepaper was evaluated according to the same criteria as in the above (a1).

[0081] (b) Fixing property A straight line with a length of 5 cm was written on one surface of a tablet medicine wrapping sheet made of polyethylene terephthalate (PET) or cellophane to form a coating film of the ink composition for the oil-based marking pen, and it was dried. In this way, a sample having a film formed by drying the coating film on one surface of the tablet medicine wrapping sheet was prepared. The sample was placed on an upper pan scale, and while applying a load of 1 kgf (≈9.8 N), the state of peeling of the film when rubbing the film with a finger was observed, and the fixing property of the ink composition for the oil-based marking pen to the adherend surface was evaluated according to the following criteria. A: No peeling is seen at all. B: Peeling is seen in part, but the handwriting can be confirmed. C: The peeling is remarkable and the handwriting cannot be confirmed.

[0082] (c) Quick-drying property A straight line with a length of 5 cm was written on a tablet medicine wrapping sheet made of PET or cellophane, and after 10 seconds, the handwriting was traced, and the drying state of the handwriting was evaluated according to the following criteria based on whether there was a change in the shape of the handwriting. A: There is no change in the shape of the handwriting (the handwriting is dry). B: The shape of the handwriting has changed (the drying of the handwriting is insufficient).

[0083] (d) Precipitation property The degree of precipitation of the fatty acid glyceride component in the ink composition for oil-based marking pens was evaluated according to the following criteria starting from the state when filling the ink composition for oil-based marking pens into the refill in (2) above. A: The ink composition for oil-based marking pens is uniform and no precipitate is seen, and the filling into the refill can be carried out smoothly. B: Precipitates are seen in the ink composition for oil-based marking pens, and the filling into the refill cannot be carried out smoothly.

[0084] The results of Examples 1 to 8 and Comparative Examples 1 to 7 are shown in Table 1A, Table 1B, and Table 2. Note that Examples 1 to 8 are E1 to E8 respectively, and Comparative Examples 1 to 7 are C1 to C7 respectively. Fixing property 1 and quick-drying property 1 are the evaluation results when using a tablet medicine wrapping sheet made of PET, and fixing property 2 and quick-drying property 2 are the evaluation results when using a tablet medicine wrapping sheet made of cellophane.

[0085]

Table 1A

[0086]

Table 1B

[0087] As shown in Table 1A and Table 1B, in C1 - C7, it is impossible to achieve both high fixability to the adherend surface and excellent cap - off property in a dry environment. More specifically, when the content of the oil - soluble resin exceeds 15% by mass, the cap - off property in a dry environment deteriorates (comparison between E1 and E2 and C1). When the content of the oil - soluble resin is less than 5% by mass, the fixability to the adherend surface deteriorates (comparison between E2 and C2). Also, when the ink composition for an oil - based marking pen contains only one of the sucrose fatty acid ester component or the fatty acid glyceride component, even if the content of the oil - soluble resin is 5 - 15% by mass, the cap - off property in a dry environment deteriorates (comparison between E2 and C6 and C7). In contrast, in E1 - E8, high fixability can be obtained for both PET and cellophane adherend surfaces, and excellent cap - off property in a dry environment can be ensured.

[0088] From the viewpoint of ensuring high quick - drying property, the ethanol content is preferably 70% by mass or more. From the viewpoint of ensuring high fillability (or fluidity (ink flow)) of the ink composition for an oil - based marking pen, the content of the fatty acid glyceride component is preferably 3.0% by mass or less, and more preferably 2.5% by mass or less.

[0089] Table 2 shows more detailed evaluation results of the cap - off property of E1 - E2 and C1 - C3 and C5 in a wet environment and a dry environment.

[0090]

Table 2

[0091] As shown in Table 2, even in the ink compositions for oil-based marking pens of C1 to C3 and C5, in a wet environment (general atmospheric environment), relatively high cap-off performance can be ensured even after 2 days have passed since cap-off. However, in the ink compositions for oil-based marking pens of C1, C3, and C5, in a harsh dry environment as described above, after 16 hours or 24 hours have passed since cap-off, the streaks when writing are remarkable, and it is difficult to ensure high cap-off performance. On the other hand, in the case of E1 and E2, in a dry environment, high cap-off performance can be ensured even after 16 hours or 24 hours have passed since cap-off, compared to C1, C3, and C5. In addition, in the ink composition for the oil-based marking pen of C2, high cap-off performance in a dry environment can be obtained, but the fixing property to the adherend surface is low.

[0092] In a dry environment, when the cap of an oil-based marking pen is removed and left for a long time with air flowing, it is difficult to suppress the streaks when rewriting even after putting the cap on and waiting for some time. Therefore, in C1, C3, and C5, the rewritability is low. On the other hand, even when the cap is removed and left under such harsh conditions, in the case of E1 and E2, higher rewritability can be obtained compared to C1, C3, and C5.

[0093] 《Examples 9 to 25 and Comparative Examples 8 to 9》 Ink compositions for oil-based marking pens are prepared with the components and amounts shown in Tables 3 and 4. In some examples, ethanol and dipropylene glycol monomethyl ether were used as solvents. Otherwise, the ink compositions for oil-based marking pens were prepared in the same manner as in the case of Examples 1 to 8, and oil-based marking pens were produced. In Comparative Example 8, polyether-modified silicone oil, sucrose fatty acid ester component, and fatty acid glyceride component were not used.

[0094] Among the components in Tables 3 and 4, the components not described in Tables 1A and 1B are as follows. (i) Oil-soluble dye 3 (manufactured by Orient Chemical Industries, Nigrosine dye, VALIFAST BLACK 1821) (ii) Oil-soluble resin 2 (manufactured by EVONIK, water-added ketone resin, TEGO VARIPLUS SK) (iii) Oil-soluble resin 3 (manufactured by Arakawa Chemical Industries, Ltd., alkylphenol resin, Tamanol 510) (iv) Oil-soluble resin 4 (manufactured by Arakawa Chemical Industries, Ltd., rosin resin, Rosin WW) (v) Oil-soluble resin 5 (manufactured by Arakawa Chemical Industries, Ltd., rosin ester resin, Markid 33) (vi) Oil-soluble resin 6 (manufactured by Arakawa Chemical Industries, Ltd., alkylphenol resin, Tamano-ル 100S) (vii) Polyether-modified silicone oil 2 (manufactured by MOMENTIVE Performance Materials, TSF4460, EO / PO = 0 / 100) (viii) Polyether-modified silicone oil 3 (manufactured by MOMENTIVE Performance Materials, TSF4446, EO / PO = 100 / 0) (ix) Polyether-modified silicone oil 4 (manufactured by MOMENTIVE Performance Materials, TSF4452, EO / PO = 50 / 50)

[0095] The following evaluations were carried out using the prepared oil-based marking pen or the prepared ink composition for the oil-based marking pen. (e) Drying speed In a constant temperature chamber at 20°C and a relative humidity of 65%, using an oil-based marking pen, write 12 characters of a V shape with a size of 20 mm in length and 20 mm in width on a glass plate every 5 seconds. 5 seconds after writing the last V shape, place a white art paper on it so that the art surface contacts the handwriting, and place a 1.5 kgf (≈14.7 N) load on the white art paper from above to press it against the handwriting. After standing still for 1 minute after placing the load, remove the load, separate the art paper from the glass plate, and observe the state of ink transfer to the art paper. The time (seconds) required for drying was determined from the position of the V shape corresponding to the portion where transfer was confirmed. The glass plate and the white art paper were stored overnight in a constant temperature chamber at 20°C and a relative humidity of 65% and then subjected to the above test. In addition, when the drying time was 1 minute or more, the V shape was written every 10 seconds and the test was conducted in the same manner as above.

[0096] (f) Cap-off property in a general atmospheric environment (humid environment) In accordance with the case of Example 1 and in accordance with the case of (a2) above, after removing the cap of the oil-based marking pen and leaving it in a horizontal state, the cap-off property was evaluated when writing was done 1 day, 7 days, 14 days, and 28 days later. However, the cap-off property was evaluated for writing on each of a PET sheet and a white paper notepad. In Tables 3 and 4, the numerical values in parentheses are the evaluation results for writing on the white paper notepad, and the numerical values outside the parentheses are the evaluation results for writing on the PET sheet. The evaluation was conducted according to the same criteria as in (a1) above.

[0097] (g) Fixing property Using a PET sheet, the fixing property was evaluated in the same manner as the evaluation of the fixing property in (b) above.

[0098] (h) Water resistance One surface of a PET sheet was written with an oil-based marking pen and dried. The PET sheet was immersed in a water bath for 10 minutes. The PET sheet was taken out of the water bath, and the state of the handwriting was evaluated according to the following criteria. A: No change is seen in the handwriting compared to before immersion in the water bath. B: Slight change is seen in the handwriting. C: The change in handwriting is significant.

[0099] The results of Examples 9 to 25 and Comparative Examples 8 to 9 are shown in Tables 3 and 4. Note that Examples 9 to 25 are E9 to E25 respectively, and Comparative Examples 8 to 9 are C8 to C9 respectively.

[0100]

Table 3

[0101]

Table 4

[0102] As shown in Table 3, when sucrose fatty acid ester and fatty acid triglyceride are not used, the cap-off property in a wet environment (general atmospheric environment) is extremely low (C8). Also, when the content of the oil-soluble resin is less than 5% by mass, the fixing property to the adherend surface is low (C9). In contrast, in the examples, even when the type of polyether-modified silicone oil is changed, high fixing property and excellent cap-off property under wet conditions can be obtained (E9 to E14).

[0103] Further, when the content of the oil-soluble resin in the ink composition for an oil-based marking pen is 5% by mass or more and 15% by mass or less, when using a polyether-modified silicone oil having a repeating structure of oxyalkylene units with the ratio (EO ratio) of the total number of oxyethylene units to the total number of oxyalkylene units being 50% or more, the drying speed can be significantly shortened (comparison between E9 to E10 and E11 to E14). However, when the content of the oil-soluble resin is less than 5% by mass, it is difficult to shorten the drying speed even when using such a polyether-modified silicone oil with an EO ratio of 50% or more (C9). Also, when the content of the oil-soluble resin exceeds 15% by mass, since the solid content increases, the cap-off property deteriorates.

[0104] As shown in Table 4, from the viewpoint of shortening the drying rate, the content of the polyether-modified silicone oil containing oxyethylene units is preferably 0.1% by mass or more (particularly, 0.3% by mass or more or 0.4% by mass or more) (comparison between E15 and E12 and E17 to E25). From the same viewpoint, the content of the polyether-modified silicone oil containing oxyethylene units is preferably 1.5% by mass or less (particularly, 1.2% by mass or less or 1% by mass or less) (comparison between E16 and E12 and E17 to E25). In any of these examples, high fixability and excellent cap-off property under wet conditions can be obtained.

[0105] In addition, also in the examples of Tables 3 and 4, excellent cap-off property under drying conditions can be obtained as in the case of Examples 1 to 8.

Industrial Applicability

[0106] The ink composition for an oil-based marking pen according to the above aspect of the present invention exhibits high cap-off property in a dry environment despite having high fixability to the adherend surface. Therefore, it is particularly suitable for applications where it is used with the cap removed for a long time. However, the application of the ink composition for an oil-based marking pen is not limited to this case.

Claims

1. A solvent containing ethanol, an oil-soluble dye, an oil-soluble resin, a sucrose fatty acid ester component, and a fatty acid glyceride component, wherein the proportion of the ethanol in the solvent is 60% by mass or more, the content of the oil-soluble resin is 5% by mass or more and 15% by mass or less, the content of the sucrose fatty acid ester component is 0.1% by mass or more and 1% by mass or less, and the content of the fatty acid glyceride component is 0.5% by mass or more and 3.0% by mass or less, an ink composition for an oil-based marking pen (however, excluding the case of containing a nonionic surfactant composed of an oligomer having a perfluoroalkyl group).

2. The ink composition for an oil-based marking pen according to claim 1, wherein the fatty acid glyceride component contains at least fatty acid triglyceride.

3. The ink composition for an oil-based marking pen according to claim 1 or 2, wherein the proportion of the ethanol in the solvent is 70% by mass or more.

4. The ink composition for an oil-based marking pen according to any one of claims 1 to 3, further containing a polyether-modified silicone oil.

5. The ink composition for an oil-based marking pen according to claim 4, wherein the polyether-modified silicone oil contains a repeating structure of oxyalkylene units and contains at least an oxyalkylene unit in which the alkylene has 2 or 3 carbon atoms as the oxyalkylene unit.

6. The polyether-modified silicone oil according to claim 4 or 5 contains a repeating structure of oxyalkylene units and contains at least an oxyethylene unit as the oxyalkylene unit, and the ratio of the total number of the oxyethylene units to the total number of the oxyalkylene units is 50% or more.

7. The ink composition for an oil-based marking pen according to any one of claims 4 to 6, wherein the content of the polyether-modified silicone oil is 0.01% by mass or more and 2% by mass or less.

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