Ink composition for oil-based ballpoint pen, ink refill and oil-based ballpoint pen

Abstract

To provide an ink composition for oil-based ballpoints that can prevent the composition itself from leaking from an ink refill even when the ink refill is centrifuged, with the composition loaded into the ink refill, and to provide an ink refill and an oil-based ballpoint.SOLUTION: An ink composition for oil-based ballpoints contains a solvent, a resin, a colorant, and fine particles, the fine particles having an average particle size of 600 nm or more. The viscosity at 25°C and a shear rate of 7.5 / s is less than 1500 mPa s.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an ink composition for an oil-based ballpoint pen, an ink refill, and an oil-based ballpoint pen.

Background Art

[0002] An ink composition used in an oil-based ballpoint pen generally has a high viscosity of 6,000 to 15,000 mPa·s at 25°C. For this reason, in an oil-based ballpoint pen using such an ink composition, the writing feel tends to be heavy, and a high writing pressure is required to transfer the ink to paper.

[0003] Therefore, in recent years, in order to achieve a light writing feel when using an oil-based ballpoint pen, an ink composition with a reduced viscosity has been proposed.

[0004] For example, in Patent Document 1 below, as an ink composition for an oil-based ballpoint pen, a ballpoint pen oil-based ink composition containing a colorant, a solvent, and inorganic fine particles having a primary particle diameter of 1 to 100 nm and having a viscosity of 100 to 3000 mPa·s at a shear rate of 38.30 / second is disclosed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the ink composition for an oil-based ballpoint pen described in Patent Document 1 described above had the following problems during the production of the ink refill.

[0007] That is, when manufacturing an ink refill, centrifugation is performed on the ink refill to remove the air inside the ink refill while the ink refill is filled with the ink composition for an oil-based ballpoint pen. However, the ink composition for an oil-based ballpoint pen described in Patent Document 1 may leak from the tip of the ink refill due to such centrifugation.

[0008] The present invention has been made in view of the above circumstances, and an object thereof is to provide an ink composition for an oil-based ballpoint pen, an ink refill, and an oil-based ballpoint pen that can suppress leakage from the ink refill even when centrifugation is performed on the ink refill while it is filled.

Means for Solving the Problems

[0009] The inventor of the present invention considered that the cause of the above problem might be that the viscosity of the ink composition for an oil-based ballpoint pen is low. However, the inventor of the present invention intensively studied to solve the above problem even when the viscosity of the ink composition for an oil-based ballpoint pen is low. As a result, it was found that by containing fine particles having an average particle size of a specific value or more in the ink composition, the above problem can be solved even when the viscosity at 25°C and a shear rate of 7.5 / second is low.

[0010] That is, the present invention is an ink composition for an oil-based ballpoint pen containing a solvent, a resin, a colorant, and fine particles, wherein the fine particles have an average particle size of 600 nm or more, and the viscosity at 25°C and a shear rate of 7.5 / second is less than 1500 mPa·s.

[0011] The ink composition for an oil-based ballpoint pen of the present invention can suppress leakage from the ink refill even when excessive acceleration is applied by performing centrifugation on the ink refill to remove the air inside the ink refill while it is filled.

[0012] The reason why the above effects can be obtained by the ink composition for an oil-based ballpoint pen of the present invention is conjectured by the present inventor as follows.

[0013] That is, when the fine particles have the above-mentioned average particle size, the fine particles will have a large volume. Therefore, when centrifugation is performed on the ink refill with the ink composition filled therein, even if the viscosity of the ink composition is low, in the ink composition, it is considered that the fine particles are likely to become resistant to the flow of the solvent, resin, and colorant, making it difficult for the ink composition to leak from the ink refill. Thus, the present inventor conjectures that the above effects can be obtained by the ink composition for an oil-based ballpoint pen of the present invention.

[0014] In the above ink composition for an oil-based ballpoint pen, the content of the fine particles in the ink composition for an oil-based ballpoint pen is preferably 0.01% by mass or more.

[0015] This ink composition for an oil-based ballpoint pen can effectively suppress leakage from the ink refill even when centrifugation is performed on the ink refill with the ink composition filled therein.

[0016] Further, the present invention is an ink refill that houses the above-described ink composition for an oil-based ballpoint pen.

[0017] This ink refill can suppress the leakage of the ink composition for an oil-based ballpoint pen even when centrifugation is performed. Therefore, the ink refill of the present invention can suppress a decrease in the filling amount of the ink composition. Also, since the ink refill of the present invention can suppress the leakage of the ink composition, the proportion of ink refills to be discarded can be reduced, or the wiping operation of the ink composition can be reduced.

[0018] Further, the present invention is an oil-based ballpoint pen that includes the above-described ink refill.

[0019] This oil-based ballpoint pen has an ink refill containing the above-described ink composition for oil-based ballpoint pens. The above-described ink refill can suppress the leakage of the ink composition for oil-based ballpoint pens from the ink refill even when centrifugation is performed, and can suppress a decrease in the filling amount of the ink composition. Therefore, the oil-based ballpoint pen of the present invention can sufficiently contain the ink composition. Further, according to the oil-based ballpoint pen of the present invention, the leakage of the ink composition is sufficiently suppressed. For this reason, the proportion of discarded oil-based ballpoint pens can be reduced, or the wiping work of the ink composition can be reduced.

[0020] The above oil-based ballpoint pen has the ink refill having a ball, a ballpoint pen tip for holding the ball, and an ink storage tube connected to the ballpoint pen tip, and the ink composition for oil-based ballpoint pens is stored in the ink storage tube. In the ballpoint pen tip, it is preferable that the movement amount of the ball along the longitudinal direction of the ink storage tube is 5 to 20 μm.

[0021] In this case, the ink composition can be easily discharged from the oil-based ballpoint pen as compared with the case where the movement amount of the ball is less than 5 μm. Further, when the movement amount of the ball is within the above range, the excessive discharge of the ink composition from the oil-based ballpoint pen can be suppressed as compared with the case where it exceeds 20 μm.

Advantages of the Invention

[0022] According to the present invention, there are provided an ink composition for oil-based ballpoint pens, an ink refill, and an oil-based ballpoint pen that can suppress leakage from the ink refill even when centrifugation is performed on the ink refill in a filled state.

Embodiments for Carrying Out the Invention

[0023] Hereinafter, embodiments of the present invention will be described in detail.

[0024] <Ink Composition for Oil-Based Ballpoint Pens> The ink composition for an oil-based ballpoint pen of the present invention (hereinafter, may be simply referred to as "ink composition") contains a solvent, a resin, a colorant, and fine particles. Here, the fine particles have an average particle diameter of 600 nm or more, and the viscosity of the ink composition at 25 °C and a shear rate of 7.5 / second is less than 1500 mPa·s.

[0025] Even when the ink composition of the present invention is centrifuged with respect to the ink refill in order to remove the air in the ink refill in the state of being filled in the ink refill, leakage from the ink refill can be suppressed.

[0026] Hereinafter, the above ink composition will be described in detail.

[0027] (A) Solvent The solvent contains an organic solvent.

[0028] Examples of the organic solvent include alcohols such as 3-methoxy-3-methyl-1-butanol, ethoxytriglycol, benzyl alcohol, ethylene glycol, triethylene glycol, propylene glycol, and polyethylene glycol; ethers such as propylene glycol monomethyl ether, dipropylene glycol methyl ether, tripropylene glycol methyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol monomethyl ether; and aliphatic alcohols having 8 or more carbon atoms such as octanol. These can be used alone or in combination of two or more. When the ink composition contains a dye, the organic solvent preferably contains an aromatic ring in the molecule from the viewpoint of the solubility of the dye. Further, the organic solvent preferably further contains 3-methoxy-3-methyl-1-butanol. When the organic solvent further contains 3-methoxy-3-methyl-1-butanol, even when the ink composition is centrifuged with respect to the ink refill in the state of being filled in the ink refill, leakage from the ink refill can be more suppressed.

[0029] The content rate of the solvent in the ink composition is not particularly limited, but is preferably 30 to 70% by mass, and more preferably 40 to 60% by mass. In this case, compared with the case where the content rate of the solvent in the ink composition is less than 30% by mass, the viscosity of the ink composition is further reduced, so that a lighter writing feeling can be realized when using an oil-based ballpoint pen. Further, the content rate of the resin in the ink composition is preferably 15% by mass or less. In this case, compared with the case where the content rate of the resin in the ink composition exceeds 15% by mass, it is possible to suppress the viscosity of the ink composition from becoming too high, so that a lighter writing feeling can be realized when using an oil-based ballpoint pen.

[0030] (B) Resin The resin is a resin soluble in a solvent and is used as a viscosity modifier for the ink composition. Examples of such resins include maleic resin, ketone resin, rosin resin, xylene resin, phenol resin, amide resin, terpene resin, terpene phenol resin, butyral resin and the like.

[0031] Note that the maleic resin is a resin containing a structural unit derived from maleic acid or maleic anhydride, and may be a homopolymer or a copolymer.

[0032] The ketone resin is a resin having a ketone group.

[0033] The content rate of the resin in the ink composition is not particularly limited, but is usually 20% by mass or less. Further, the content rate of the resin in the ink composition is preferably 15% by mass or less. In this case, compared with the case where the content rate of the resin in the ink composition exceeds 15% by mass, it is possible to suppress the viscosity of the ink composition from increasing too much, so that a lighter writing feeling can be realized when using an oil-based ballpoint pen.

[0034] (C) Colorant The colorant contains at least one of a pigment and a dye.

[0035] (Pigment) The pigment is not particularly limited as long as it can be dispersed in an organic solvent. Examples of the pigment include organic pigments and inorganic pigments. These can be used alone or in combination of two or more kinds.

[0036] Examples of the organic pigment include insoluble azo pigments, phthalocyanine pigments, perylene pigments, quinacridone pigments, diketopyrrolopyrrole-based pigments, and the like.

[0037] Examples of the inorganic pigment include carbon black, titanium oxide, metal powder, and the like.

[0038] The content of the pigment in the colorant is not particularly limited and may be appropriately determined according to the desired color state.

[0039] (Dye) The dye is not particularly limited as long as it can be dissolved in a solvent. Examples of the dye include SPIRIT BLACK 61F, VALIFAST VIOLET 1701, VALIFAST VIOLET 1704, VALIFAST YELLOW1109, 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, VALIFAST BLACK 3870 (manufactured by Orient Chemical Industries Co., Ltd. as above), Aizen Spilon BLACK GHMSpecial, Aizen Spilon VIOLET C-RH, Aizen Spilon YELLOW C-GH new, Aizen Spilon BLUE C-RH, Aizen Spilon S.P.T.BLUE -111, Aizen Spilon S.P.T.BLUE -121 (manufactured by Hodogaya Chemical Co., Ltd. as above), and the like. These can be used alone or in combination of two or more.

[0040] The content rate of the dye in the colorant is not particularly limited and may be appropriately determined according to the desired color state.

[0041] (D) Fine particles Examples of the fine particles include organic particles and inorganic particles. Examples of the organic substance constituting the organic particles include resins and the like. Examples of the resin include styrene resins, acrylic resins, styrene-acrylic resins, benzoguanamine-formaldehyde condensates, silicone resins, and the like. Among them, styrene-acrylic resins are preferable. In this case, the fine particles are likely to be uniformly dispersed in the organic solvent.

[0042] Examples of the inorganic substance constituting the inorganic particles include inorganic oxides such as silica, titanium dioxide, calcium carbonate, and aluminum oxide.

[0043] The fine particles may be solid or hollow.

[0044] The shape of the fine particles may be spherical or non-spherical.

[0045] The fine particles have an average particle diameter of 600 nm or more. Here, the "average particle diameter" can be measured by a laser diffraction particle size distribution measurement method based on volume.

[0046] From the viewpoint of suppressing the leakage of the ink composition, the average particle diameter of the fine particles is preferably 700 nm or more. The average particle diameter of the fine particles may be larger than 1000 nm.

[0047] The content rate of the fine particles in the ink composition is not particularly limited, but is preferably 0.01% by mass or more. In this case, even when the ink composition filled in the ink refill is centrifuged with respect to the ink refill, the leakage from the ink refill can be effectively suppressed.

[0048] The content rate of the fine particles in the ink composition is preferably 0.1% by mass or more. In this case, compared with the case where the content rate of the fine particles in the ink composition is less than 0.1% by mass, even when the ink composition filled in the ink refill is centrifuged with respect to the ink refill, the leakage from the ink refill can be more effectively suppressed.

[0049] Also, from the viewpoint of stably dispersing the fine particles in the ink composition, the content rate of the fine particles in the ink composition is preferably 3% by mass or less.

[0050] More preferably, the content rate of the fine particles in the ink composition is 1% by mass or less.

[0051] (E) Other components In addition to the above (A) to (D), the ink composition may contain, as necessary, known additives such as a dispersant, a thread-drawing property-imparting agent, a lubricant, an anti-slipping agent, a rust inhibitor, etc., as long as the properties of the ink composition are not impaired.

[0052] (F) Viscosity of the ink composition The viscosity of the ink composition at 25°C and a shear rate of 7.5 / second is less than 1500 mPa·s.

[0053] In this case, since the viscosity of the ink composition is low, a light writing feel can be achieved when using an oil-based ballpoint pen.

[0054] The viscosity of the ink composition is more preferably less than 1200 mPa·s. In this case, the viscosity of the ink composition becomes lower, and a lighter writing feel can be achieved when using an oil-based ballpoint pen. However, the viscosity of the ink composition is preferably 50 mPa·s or more, more preferably 100 mPa·s or more, and particularly preferably 500 mPa·s or more.

[0055] <Ink refill> Next, the ink refill of the present invention will be described. The ink refill of the present invention is an ink refill that houses the above-described ink composition for an oil-based ballpoint pen.

[0056] The ink refill has a ball, a ballpoint pen tip that holds the ball, and an ink storage tube connected to the ballpoint pen tip. And the above-described ink composition for an oil-based ballpoint pen is stored in the ink storage tube.

[0057] According to this ink refill, even when centrifugation is performed, leakage of the oil-based ballpoint pen ink composition from the ball tip of the ink refill can be suppressed. Therefore, the ink refill of the present invention can suppress a decrease in the filling amount of the ink composition. Further, since the ink refill of the present invention can suppress leakage of the ink composition, the proportion of ink refills to be discarded can be reduced, or the wiping operation of the ink composition can be reduced.

[0058] <Oil-based ballpoint pen> Next, the oil-based ballpoint pen of the present invention will be described. The oil-based ballpoint pen of the present invention includes the above-described ink refill and an exterior body that houses the ink refill.

[0059] This oil-based ballpoint pen has an ink refill that contains the above-described oil-based ballpoint pen ink composition. The above-described ink refill can suppress leakage of the ink composition even when centrifugation is performed, and can suppress a decrease in the filling amount of the ink composition. Therefore, the oil-based ballpoint pen of the present invention can sufficiently contain the ink composition. Further, according to the oil-based ballpoint pen of the present invention, leakage of the ink composition is sufficiently suppressed. Therefore, the proportion of oil-based ballpoint pens to be discarded can be reduced, or the wiping operation of the ink composition can be reduced.

[0060] In the above oil-based ballpoint pen, at the ballpoint pen tip, the movement amount (movable range) of the ball along the longitudinal direction of the ink storage tube is preferably 5 to 20 μm, more preferably 7 to 17 μm, and particularly preferably 10 to 15 μm.

[0061] In this case, compared with the case where the movement amount of the ball is less than 5 μm, the ink composition can be easily discharged from the oil-based ballpoint pen. Further, when the movement amount of the ball is within the above range, compared with the case where it exceeds 20 μm, it is possible to suppress the ink composition from being excessively discharged from the oil-based ballpoint pen.

Examples

[0062] Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

[0063] Specifically, the following organic solvents, resins, colorants, fine particles, lubricants, drawability imparting agents, and anti-sagging agents were used in the examples or comparative examples.

[0064] <Organic solvent> · Benzyl alcohol · Ethylene glycol monophenyl ether · 3-Methoxy-3-methyl-1-butanol · Propylene glycol monomethyl ether

[0065] <Resin> · Ketone resin (trade name "TEGO (registered trademark) VariPlus AP", manufactured by Evonik Industries AG) · Maleic resin (trade name "Markide No33", manufactured by Arakawa Chemical Industries, Ltd.) · Terpene phenol resin (trade name "YS Polyster K125", manufactured by Yasuhara Chemical Co., Ltd.)

[0066] <Colorant> (Dye) · VALIFAST RED 1308 (trade name, manufactured by Orient Chemical Industries Co., Ltd.) · OIL YELLOW 107 (trade name, manufactured by Orient Chemical Industries Co., Ltd.) (Pigment) · Organic pigment (Pigment Red 254)

[0067] <Fine particles> · Styrene resin particles 1 (trade name "Glossdale TM 240V", manufactured by Mitsui Chemicals, Inc., average particle size 500 nm, non-spherical (erythrocyte type), solid content 43% by mass) · Styrene resin particles 2 (trade name "Glossdale TM"207S", manufactured by Mitsui Chemicals, Inc., average particle size 700 nm, spherical, solid content 52 mass%) · Styrene acrylic resin particles 1 (trade name "Nippol MH-8055", manufactured by Nippon Zeon Co., Ltd., average particle size 800 nm, hollow, solid content 30 mass%) · Styrene acrylic resin particles 2 (trade name "Nippol MH-8109", manufactured by Nippon Zeon Co., Ltd., average particle size 1000 nm, hollow, solid content 27 mass%) · Silica fine particles 1 (trade name "Seehoster KE-P100", manufactured by Nippon Shokubai Co., Ltd., average particle size 1000 nm, spherical, solid content 100 mass%) · Silica fine particles 2 (trade name "Seehoster KE-P150", manufactured by Nippon Shokubai Co., Ltd., average particle size 1500 nm, spherical, solid content 100 mass%) · Silica fine particles 3 (trade name "Seehoster KE-P250", manufactured by Nippon Shokubai Co., Ltd., average particle size 2500 nm, spherical, solid content 100 mass%)

[0068] <Lubricant> Phosphate ester (trade name "Prisurf A207H", manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

[0069] <Yarn-drawing property imparting agent> · Polyvinylpyrrolidone (trade name "PVP K-90", manufactured by Nippon Shokubai Co., Ltd.) · Butyral resin

[0070] <Anti-sagging agent> · Modified castor oil fatty acid ester (trade name "Rick Saizer GR301", manufactured by Ito Seiyu Co., Ltd.)

[0071] (Examples 1 to 11 and Comparative Examples 1 to 3) Using a reciprocating rotary stirrer agitator (manufactured by Shimazaki Engineering Co., Ltd.) at a frequency of 50 Hz, an organic solvent, resin, colorant, fine particles, lubricant, yarn-drawing property imparting agent, and anti-sagging agent were mixed at the contents shown in Tables 1 to 3, and an ink composition was obtained while heating at 60°C for 5 hours.

[0072] Then, for the obtained ink composition, the viscosity was measured at 25°C and a shear rate of 7.5 / second using a digital viscometer (product name "DV-2+PRO", manufactured by Brookfield). The results are shown in Tables 1 to 3.

[0073] <Leakage suppression effect of ink composition> Regarding the ink compositions obtained in Examples 1 to 11 and Comparative Examples 1 to 3, the leakage suppression effect of the ink composition was evaluated when centrifugation was performed on the ink refill with the ink refill filled as follows.

[0074] That is, the ink refill has a ball, a ball pen tip that holds the ball, and an ink storage tube connected to the ball pen tip. Here, the ball is made of stainless steel and the ball diameter is 0.7 mm. Then, the ink compositions obtained in Examples 1 to 11 and Comparative Examples 1 to 3 were filled into the ink storage tubes of the ink refills. In this way, 50 ink refills were prepared for each example or comparative example. At this time, in the ink refill, the movement amount (movable range) of the ball along the longitudinal direction of the ink storage tube was 12 μm.

[0075] Next, the pen tip of the above ink refill was covered with a cap, fixed to a centrifuge (manufactured by SEJONG MACHINE), and a centrifugation operation was performed at an acceleration of 550 G (5390 m / s 2 ) for 20 minutes, and the number of ink refills from which the ink composition leaked out from the tip of the chip was counted. At this time, it was determined that the ink composition had leaked out with the state that ink adhered to the inside of the cap. Then, based on the number of ink refills from which the ink composition leaked out from the chip and the following formula, the leakage rate of the ink composition was calculated. Leakage rate of ink composition (%) = 100 × number of ink refills from which the ink composition leaked out from the chip / number of ink refills on which the centrifugation operation was performed

[0076] Then, based on the following criteria, the leakage suppression effect of the ink composition in the oil-based ballpoint pen was evaluated. The results are shown in Tables 1 to 3. 〇 ··· The leakage rate of the ink composition is 30% or less × ··· The leakage rate of the ink composition is greater than 30%

Table 1

Table 2

Table 3

[0077] From the results shown in Tables 1 to 3, all of the ink compositions of Examples 1 to 11 had a small leakage rate when centrifuged with respect to the ink refill in the state of being filled in the ink refill, and the leakage suppression effect of the ink composition was "〇". On the other hand, the ink compositions of Comparative Examples 1 to 3 had a large leakage rate when centrifuged with respect to the ink refill in the state of being filled in the ink refill, and the leakage suppression effect of the ink composition was "×".

[0078] From the above, it was confirmed that the ink composition for the oil-based ballpoint pen of the present invention can suppress leakage from the ink refill even when centrifuged with respect to the ink refill in the state of being filled in the ink refill.

Claims

1. An ink composition for oil-based ballpoint pen ink refills, comprising a solvent, a resin, a colorant, and fine particles, the resin is soluble in the solvent, The fine particles have an average particle size of 600 nm or more, the fine particles are organic particles or inorganic particles, and the organic material constituting the organic particles is a styrene-based resin, an acrylic-based resin, a styrene-acrylic resin, or a benzoguanamine-formaldehyde condensate; An ink composition for oil-based ballpoint pen ink refills, having a viscosity of less than 1500 mPa·s at 25° C. and a shear rate of 7.5 / sec.

2. 2. The ink composition for refilling oil-based ballpoint pen ink according to claim 1, wherein the content of the fine particles in the ink composition for refilling oil-based ballpoint pen ink is 0.01% by mass or more.

3. An ink refill containing the ink composition for oil-based ballpoint pen ink refills according to claim 1 or 2.

4. An oil-based ballpoint pen comprising the ink refill according to claim 3.

5. The ink refill has a ball, a ballpoint pen tip that holds the ball, and an ink containing tube that is connected to the ballpoint pen tip, The ink composition for oil-based ballpoint pen ink refill is contained in the ink reservoir tube, 5. The oil-based ballpoint pen according to claim 4, wherein in the ballpoint pen tip, the amount of movement of the ball along the longitudinal direction of the ink reservoir tube is 5 to 20 μm.

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