Ink composition for oil-based marking pen and oil-based marking pen

Abstract

To provide an ink composition for an oily marking pen which is used in an oily marking pen, can restore the oily marking pen to a writable state in an early period even after a cap-off state has been continuous for a long period of time, and can suppress degradation in writing performance by the oily marking pen, and an oily marking pen.SOLUTION: An ink composition for an oily marking pen contains an organic solvent, a coloring agent, and a resin soluble in the organic solvent, wherein the resin contains a polyamide resin, and the ink composition for the oily marking pen contains an amide compound having an amide bond.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] When an oil-based marking pen is left uncapped (a so-called cap-off state) for a long period of time, the tip begins to dry out, and even if you try to start writing with the oil-based marking pen after that, it may be difficult for the oil-based marking pen to return to a writable state. For this reason, for example, Patent Document 1 listed below describes adding a cap-off agent such as a fatty acid polyamine polyamide to an ink composition for an oil-based marking pen so that writing can be started smoothly without smearing even after the pen has been left in the capped state for a long period of time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-54922 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the oil-based marking pen ink composition described in the above-mentioned Patent Document 1 has the following problems.

[0005] That is, the oil-based marking pen ink composition described in Patent Document 1 still has room for improvement in terms of quickly restoring the oil-based marking pen to a writable state even when used in an oil-based marking pen and the oil-based marking pen is left in a cap-off state for a long period of time and then the oil-based marking pen is started to write. Furthermore, in order to quickly restore the oil-based marking pen to a writable state even after the cap-off state has been maintained for a longer period of time, it is also possible to increase the amount of cap-off agent added. However, in this case, the viscosity of the oil-based marking pen ink composition increases, and when the ink composition for an oil-based marking pen is used in an oil-based marking pen, problems with writing performance may occur, such as failure to write with the oil-based marking pen.

[0006] The present invention has been made in view of the above circumstances, and aims to provide an ink composition for an oil-based marking pen, which can be used in an oil-based marking pen to quickly restore the oil-based marking pen to a writable state even after the cap has been off for a long period of time, and which can also suppress a decrease in the writing performance of the oil-based marking pen, and an oil-based marking pen. [Means for solving the problem]

[0007] As a result of extensive research to solve the above problems, the present inventors have found that the above problems can be solved by the following invention.

[0008] That is, the present invention provides an ink composition for an oil-based marking pen, which comprises an organic solvent, a resin soluble in the organic solvent, and a colorant, wherein the resin comprises a polyamide resin, and the ink composition for an oil-based marking pen comprises an amide compound having an amide bond.

[0009] The ink composition for an oil-based marking pen of the present invention can be used in an oil-based marking pen to quickly restore the oil-based marking pen to a writable state even after the cap has been off for a long period of time, and can also suppress deterioration in the writing performance of the oil-based marking pen.

[0010] The reason why the ink composition for an oil-based marking pen of the present invention provides the above-mentioned effects is not clear, but the present inventors speculate as follows.

[0011] That is, when an ink composition for an oil-based marking pen is used in an oil-based marking pen having a tip and a cap, and the oil-based marking pen is left in the cap-off state for a long period of time, the organic solvent in the ink composition evaporates from the tip. Then, because the polyamide resin contains amide bonds, as the organic solvent evaporates, the polyamide resin molecular chains approach each other and are attracted to each other by hydrogen bonds between the amide bonds. Here, if the ink composition for an oil-based marking pen does not contain an amide compound, the amount of crystalline portions in which the polyamide resin molecular chains are regularly arranged increases. As a result, the ink composition contained in the tip hardens, making it difficult for the ink composition to be supplied from the ink supply unit to the tip. As a result, when attempting to start writing with the oil-based marking pen, writing with the oil-based marking pen becomes difficult, and writing failures are likely to occur. In contrast, when the ink composition for an oil-based marking pen contains an amide compound as in the present invention, the amide compound has a high affinity with polyamide resins, which also contain amide bonds, and is therefore easily accessible to polyamide resins. Furthermore, because the amide compound and polyamide resin share the same functional group (polyamide bond), there is little risk of unnecessary chemical reactions that could cause writing failure. Therefore, as the organic solvent evaporates, the polyamide resins approach each other and attempt to attract each other through hydrogen bonds between the amide bonds. However, the amide compound penetrates between the polyamide resins, reducing the crystalline portions where the polyamide resin molecular chains are regularly arranged, and the ink composition contained in the tip remains soft even after hardening. As a result, when writing with an oil-based marking pen is started, the ink composition is supplied to the tip with only the frictional force of writing, allowing the written line to be quickly restored.

[0012] Furthermore, since the ink composition of the present invention contains, in addition to the polyamide resin that can function as a cap-off agent, an amide compound that contributes to early recovery of writing after a prolonged cap-off state, it is possible to reduce the amount of polyamide resin added, which can cause an increase in viscosity of the ink composition for oil-based marking pens.As a result, it is possible to reduce the viscosity of the ink composition compared to ink compositions that do not contain the amide compound, and it is possible to suppress deterioration in writing performance.

[0013] From the above, the present inventors speculate that the above effects can be obtained by the ink composition for an oil-based marking pen of the present invention.

[0014] In the ink composition for an oil-based marking pen, the mass ratio of the amide compound to the polyamide resin is preferably 0.3 to 3.

[0015] By using this ink composition for an oil-based marking pen in an oil-based marking pen, the oil-based marking pen can be restored to a writable state more quickly even after being left in a cap-off state for a long period of time, and deterioration of the writing performance of the oil-based marking pen can also be suppressed.

[0016] The present invention also provides an oil-based marking pen containing the ink composition for an oil-based marking pen described above.

[0017] The ink composition for an oil-based marking pen described above can be used in an oil-based marking pen to quickly restore the oil-based marking pen to a writable state even after the cap has been off for a long period of time, and can also suppress a decrease in the writing performance of the oil-based marking pen. Therefore, the oil-based marking pen of the present invention containing the ink composition for an oil-based marking pen described above can quickly restore the oil-based marking pen to a writable state even after the cap has been off for a long period of time, and can also suppress a decrease in the writing performance of the oil-based marking pen. [Effects of the Invention]

[0018] According to the present invention, there are provided an ink composition for an oil-based marking pen and an oil-based marking pen which can be used in an oil-based marking pen to quickly restore the oil-based marking pen to a writable state even after the cap has been off for a long period of time, and which can also suppress deterioration in the writing performance of the oil-based marking pen. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail.

[0020] <Ink composition for oil-based marking pens> The ink composition for an oil-based marking pen of the present invention (hereinafter sometimes simply referred to as the "ink composition") contains an organic solvent, a colorant, and a resin soluble in the organic solvent. Here, the resin contains a polyamide resin, and the ink composition contains an amide compound having an amide bond.

[0021] The ink composition of the present invention can be used in an oil-based marking pen to quickly restore the oil-based marking pen to a writable state even after the cap has been off for a long period of time, and can also suppress deterioration in the writing performance of the oil-based marking pen.

[0022] The ink composition will now be described in detail.

[0023] (A) Organic solvent The organic solvent can be appropriately selected as long as it can dissolve the colorant and resin and has physical properties such as vapor pressure and surface tension within the ranges used in ink compositions for general oil-based marking pens. Examples of such organic solvents include water-soluble organic solvents and water-insoluble organic solvents. These can be used alone or in combination. Water-soluble organic solvents are those whose water solubility at 25°C is 10 g / 100 g or more.

[0024] Examples of such water-soluble organic solvents include alcohols such as 3-methoxy-3-methyl-1-butanol, ethoxytriglycol, ethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, ethanol, methanol, t-butyl alcohol, isopropyl alcohol, 1-propanol, and 2-propanol; and ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, dipropylene glycol methyl ether, dipropylene glycol monoethyl ether, diethylene glycol monobutyl ether, and tripropylene glycol methyl ether.

[0025] (non-water-soluble organic solvent) A water-insoluble organic solvent refers to an organic solvent whose solubility in water at 25°C is less than 10 g / 100 g.

[0026] Examples of such water-insoluble organic solvents include aromatic alcohols such as benzyl alcohol and phenyl glycol, aliphatic alcohols having 8 or more carbon atoms such as octanol, aromatic hydrocarbon solvents such as toluene, xylene, and ethylbenzene, aliphatic hydrocarbon solvents such as n-hexane, n-heptane, isoheptane, n-octane, and isooctane, and cycloparaffin solvents such as methylcyclohexane and ethylcyclohexane. These can be used alone or in combination of two or more.

[0027] The content of the organic solvent in the ink composition is not particularly limited, but is preferably 50 to 95% by mass, and more preferably 60 to 90% by mass. In this case, smoother writing is possible compared to when the content of the organic solvent in the ink composition is less than 50% by mass. In addition, a decrease in the density of the handwriting can be suppressed compared to when the content of the organic solvent in the ink composition is more than 95% by mass.

[0028] (B) Colorant The coloring agent may be a dye or a pigment, which may be used alone or in combination of two or more.

[0029] (dye) Examples of dyes include SPIRIT BLACK 61F, VALIFAST VIOLET 1701, VALIFAST VIOLET 1704, VALIFAST YELLOW 1109, VALIFAST YELLOW 1151, VALIFAST YELLOW 1171, OIL YELLOW 107, VALIFAST BLUE 1605, VALIFAST BLUE 1621, VALIFAST BLUE 1623, VALIFAST BLUE 2620, OIL BLUE 613, VALIFAST RED 1308, VALIFAST RED 1320, VALIFAST RED 1364, VALIFAST RED 2320, VALIFAST BLACK 3830, and VALIFAST BLACK 3870 (all manufactured by Orient Chemical Industries Co., Ltd.), Aizen Spilon BLACK GHM Special, and Aizen Spilon VIOLET C-RH, Aizen Spilon YELLOW C-GH new, Aizen Spilon BLUE C-RH, Aizen Spilon SPTBLUE-111, Aizen Spilon SPTBLUE-121 (all manufactured by Hodogaya Chemical Co., Ltd.), etc. These may be used alone or in combination of two or more.

[0030] The content of the dye in the colorant is not particularly limited and may be determined appropriately depending on the desired color state.

[0031] (pigment) The pigment in the colorant is not particularly limited, and examples of the pigment include organic pigments and inorganic pigments, which can be used alone or in combination of two or more.

[0032] Examples of organic pigments include insoluble azo pigments, phthalocyanine pigments, perylene pigments, quinacridone pigments, and diketopyrrolopyrrole pigments.

[0033] Examples of inorganic pigments include carbon black, titanium oxide, and metal powder.

[0034] The content of the pigment in the colorant is not particularly limited and may be determined appropriately depending on the desired color state.

[0035] (C) Resin The resin may be any resin that is soluble in an organic solvent and contains a polyamide resin. The resin may be composed solely of a polyamide resin, or may be a mixture of a polyamide resin and another resin.

[0036] The polyamide resin is not particularly limited as long as it is a resin having an amide bond, and examples of the polyamide resin include n-nylon and n,m-nylon. These may be used alone or in combination of two or more. Among them, modified polyamides that are soluble in alcohol are preferred.

[0037] The weight-average molecular weight of the polyamide resin is not particularly limited, but is preferably 1,000 or more, more preferably 10,000 or more, and particularly preferably 100,000 or more. When the weight-average molecular weight of the polyamide resin is 100,000 or more, the adhesion of the written lines is further improved. However, the weight-average molecular weight of the polyamide resin is preferably 500,000 or less, and more preferably 300,000 or less. When the weight-average molecular weight of the polyamide resin is 300,000 or less, the increase in viscosity of the ink composition can be further suppressed.

[0038] Examples of other resins include ketone resins, ketone aldehyde condensation resins, phenol resins, maleic resins, xylene resins, terpene phenol resins, and rosin-modified resins. These may be used alone or in combination. Among these, ketone aldehyde condensation resins, terpene phenol resins, and mixtures thereof are preferred. In this case, adhesion to non-absorbent surfaces such as glass, metal, and plastic can be improved.

[0039] The maleic resin is a resin containing structural units derived from maleic acid or maleic anhydride, and may be a homopolymer or a copolymer.

[0040] The ketone resin is a resin having a ketone group.

[0041] When the resin is a mixture of polyamide resin and other resins, the content of polyamide resin in the resin is not particularly limited, but from the viewpoint of imparting the function of quickly restoring the ink to a writable state after a long period of cap-off state, it is preferably 1.5% by mass or more, more preferably 3% by mass or more. However, from the viewpoint of maintaining a low viscosity of the ink composition, the content of polyamide resin in the resin is preferably 15% by mass or less, more preferably 10% by mass or less.

[0042] The resin content in the ink composition is not particularly limited, but is typically 30% by mass or less, and preferably 20% by mass or less. In this case, the viscosity of the ink composition can be reduced compared to when the resin content in the ink composition exceeds 30% by mass, thereby improving the writing performance when using an oil-based marking pen. The resin content in the ink composition is preferably 3% by mass or more. In this case, the viscosity of the ink composition is further increased compared to when the resin content in the ink composition is less than 3% by mass, thereby improving the fixability of the handwriting to the writing surface.

[0043] (D) Amide compounds The amide compound is not particularly limited as long as it is a compound having an amide bond. The amide compound is represented, for example, by the following formula (1). [ka]

[0044] In the above formula (1), R 1 , R 2 , R 3 each independently represents a hydrogen atom, an alkyl group, or a phenyl group.

[0045] R 1 Although may be a hydrogen atom, an alkyl group, or a phenyl group, from the viewpoints of the effect of molecular weight on the viscosity of the ink composition, solubility in solvents, and compatibility with other additives, it is preferably an alkyl group, and more preferably an alkyl group having an unsaturated double bond. In other words, the amide compound is preferably an acrylamide compound. When this ink composition is used in an oil-based marking pen, it is possible to restore the oil-based marking pen to a writable state more quickly, even after the cap has been off for a long period of time.

[0046] The mass ratio r of the amide compound to the polyamide resin is not particularly limited as long as it is greater than 0, but is preferably 0.3 to 3, and particularly preferably 0.7 to 1.5. In this case, when the mass ratio r is 0.3 to 3, the ink composition for an oil-based marking pen is used in an oil-based marking pen, and the oil-based marking pen can be restored to a writable state more quickly even after the cap has been off for a long period of time.

[0047] (E) Other ingredients In addition to the above (A) to (D), the ink composition may further contain known additives such as dispersants, stringiness imparting agents, lubricants, and rust inhibitors, as needed, within the range that does not impair the properties of the ink composition.

[0048] <Oil-based marking pen> Next, the oil-based marking pen of the present invention will be described. The oil-based marking pen of the present invention comprises the ink composition described above.

[0049] The ink composition for an oil-based marking pen described above can be used in an oil-based marking pen to quickly restore the oil-based marking pen to a writable state even after the cap has been off for a long period of time, and can also suppress a decrease in the writing performance of the oil-based marking pen. Therefore, the oil-based marking pen of the present invention containing the ink composition for an oil-based marking pen described above can quickly restore the oil-based marking pen to a writable state even after the cap has been off for a long period of time, and can also suppress a decrease in the writing performance of the oil-based marking pen. [Example]

[0050] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0051] The organic solvents, colorants, resins, and amide compounds used in the examples and comparative examples are specifically as follows.

[0052] <Organic solvents> Propylene glycol monomethyl ether ·ethanol

[0053] <Coloring agent> (dye) VALIFAST BLACK 3820 (product name, manufactured by Orient Chemical Industries Co., Ltd.)

[0054] <Resin> Ketone aldehyde condensation resin (product name "TEGO (registered trademark) VariPlus SK", manufactured by Evonik Industries Co., Ltd.) Terpene phenol resin (product name "YS Polystar K125", manufactured by Yasuhara Chemical Co., Ltd.) Polyamide resin (product name "AQ Nylon P-70", manufactured by Toray Industries, Inc., weight average molecular weight: 226,000 to 230,000, number average molecular weight: 77,000 to 82,000)

[0055] <Amide compounds> N-isopropylacrylamide (manufactured by Wako Pure Chemical Industries, Ltd., in formula (1), R 1 is a vinyl group and R 2 is an isopropyl group, and R 3 is a hydrogen atom.) Benzamide (manufactured by Wako Pure Chemical Industries, Ltd., in formula (1), R 1 is a phenyl group and R 2 is a hydrogen atom, and R 3 is a hydrogen atom.)

[0056] (Examples 1 to 5 and Comparative Examples 1 to 3) Using a magnetic stirrer, the organic solvent, colorant, resin, and amide compound were mixed to the contents shown in Table 1 while heating at 50°C for 2 hours at 400 rpm to obtain an ink composition.

[0057] <Evaluation of ink composition> The ink compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were evaluated for their ability to quickly return to the initial writing state after cap-off, the drying property of the written line, viscosity, and followability as follows.

[0058] (1) Quick recovery to the initial writing state after removing the cap The ink compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were evaluated for their ability to quickly return to their initial writing state after a prolonged period of cap-off by conducting a cap-off test. The cap-off test involved filling a YYTS5 ink cartridge (trade name, manufactured by Zebra Corporation) with the ink composition, removing the cap, and leaving the ink to stand for 6 hours at a temperature of 25°C and a humidity of 60%. A 37 mm diameter loop was then continuously written on the ink cartridge using a writing tester at a writing angle of 65°, a writing speed of 4 m / min, and a load of 50 g, and the writing distance until the written line returned without smearing was measured. Writing was performed using an acrylic fiber tip (bold side). The results are shown in Table 1. In Table 1, a mark "X" was used to indicate that the written line did not return to its initial state even after 10 m of writing.

[0059] (2) Writing line dryness The ink compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were used to form lines on a glass surface by continuously drawing five loops each measuring approximately 12 mm x 12 mm. After 10 seconds, the lines were rubbed with a rubber glove to determine whether they would smudge or fade. The writing was performed using an acrylic fiber tip (bold side). The results are shown in Table 1. In Table 1, cases where the lines did not smudge or fade were indicated with "Good," and cases where the lines smudged were indicated with "Poor."

[0060] (3) Viscosity The viscosity of the ink compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 3 was measured using an E-type viscometer (rotor: 0.8°×R24) at 25°C and 12 rpm. The results are shown in Table 1.

[0061] (4)Followability (writing performance) For the ink compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 3, a 37 mm diameter loop was continuously written using a writing tester with a plastic tip (fine writing side) at a writing angle of 65°, a writing speed of 4 m / min, and a load of 50 g, and the followability of the written line (writing performance) was evaluated. The results are shown in Table 1. If the written line was not smudged and the color of the written line was not light, it was marked with "Good." If the written line was not smudged but the color of the written line was light, it was marked with "Good." If the written line was smudged, it was marked with "Poor." If the written line was smudged, it was marked with "Poor."

[0062] [Table 1]

[0063] The results shown in Table 1 demonstrate that the ink compositions of Examples 1 to 5 all enable the oil-based marking pen to be quickly restored to a writable state, even after the cap has been left off for a long period of time, compared to the ink compositions of Comparative Examples 1 to 3. Furthermore, the ink compositions of Examples 1 to 5 all had low viscosity, and their tracking was rated "good" or "fair." Meanwhile, the ink compositions of Comparative Examples 1 and 3 had low viscosity, and their tracking was rated "good," while the ink composition of Comparative Example 2 had high viscosity, and their tracking was rated "poor."

[0064] From the above, it has been confirmed that the ink composition for oil-based marking pens of the present invention can be used in oil-based marking pens to quickly restore the oil-based marking pen to a writable state even after the cap has been off for a long period of time, and can also suppress a decline in the writing performance of the oil-based marking pen.

Claims

1. an organic solvent; A colorant; and a resin soluble in an organic solvent, the resin includes a polyamide resin, the ink composition for an oil-based marking pen contains an amide compound having an amide bond, The ink composition for an oil-based marking pen, wherein the amide compound is a compound represented by the following formula (1): [Chemical Formula 1] (In the above formula (1), R 1 represents a hydrogen atom, an alkyl group, a phenyl group, or a vinyl group, and R 2 and R 3 each independently represent a hydrogen atom, an alkyl group, or a phenyl group.)

2. 2. The ink composition for an oil-based marking pen according to claim 1, wherein the mass ratio of the amide compound to the polyamide resin is 0.3 to 3.

3. An oil-based marking pen comprising the ink composition for an oil-based marking pen according to claim 1 or 2.

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