JP5630196B2 - Ballpoint pen ink - Google Patents

Description

  The present invention provides a ballpoint pen tip comprising at least a ballpoint pen tip composed of a ball for transferring ink to a writing surface such as a paper surface as a writing member, and a ball holder that partially protrudes from the tip opening portion and rotatably holds the ball. The present invention relates to an oil-based ink for ballpoint pens housed in a ballpoint pen.

  Conventionally, oil-based ink compositions for ballpoint pens have colorants such as dyes and pigments, solvents such as glycols, glycol ethers, and high-boiling alcohols, and papers such as ketone resins, xylene resins, and rosin-derived resins. It consists of a resin whose main purpose is fixability, and a resin whose main purpose is to adjust viscosity, adjust flow properties, and prevent bottling of polyvinyl pyrrolidone, polyvinyl butyral, etc. as necessary.

  In writing with a ballpoint pen, the ink attached to the ball rotatably held at the tip of the pen tip is transferred to the paper surface as the ball rotates on the paper surface, or from the gap between the ball and the ball holder. The ink that comes out forms the handwriting by flowing out directly onto the paper surface, but not all of the ink adhering to the ball is transferred to the paper surface as the handwriting, but the ink remaining on the surface of the ball is the ball As it rotates, it tries to return to the ball holder again. A part of the ink to be returned may run on and adhere to the outer periphery of the ball holder, and a so-called bloating phenomenon may occur in which a lump of ink is dropped during writing or writing.

  Also, during writing, the ball is pressed against the paper surface and retreats, forming a gap for ink to flow out, but when writing is stopped and the ball leaves the paper surface, a small amount of ink flows out to the edge May accumulate. In the case of writing that frequently repeats contact and non-contact with the paper surface, such as writing Chinese characters, a very small amount of ink leaked out and sometimes accumulated outside the forehead. It is considered that it becomes unable to withstand gravity and falls into contact with the paper surface due to the impact of writing or the like, resulting in a so-called bloating phenomenon.

Various researches have been conducted for a long time to prevent such bloating. For example, a combination of polyvinyl pyrrolidone having a weight average molecular weight of 2 million or more (Patent Document 1), polyvinyl pyrrolidone having a weight average molecular weight of 1 million to 1.5 million and polyvinyl pyrrolidone having a weight average molecular weight of 2.5 million to 3 million (Patent Document 2) and the like.
Furthermore, the viscosity at a shear rate of 400 s ⁻¹ is 100 mPa · s or less, the viscosity at a shear rate of 5 s ⁻¹ is 1000 mPa · s or more (Patent Document 3), and the ink viscosity at a shear rate of 500 s ⁻¹ is The thing of 1000-10000 mPa * s and the n value of a non-Newtonian viscosity index is 0.45-0.90 (patent document 4) etc. are disclosed.

JP-A-10-297158 Japanese Patent Laid-Open No. 06-313143 Japanese Patent Laid-Open No. 08-239616 JP 2001-139866 A

Inks using polyvinyl pyrrolidone having a high weight average molecular weight as described in Patent Documents 1 and 2, the cohesive force of the ink becomes large, and the excess ink is returned into the ball-point pen tip by the obtained stringiness. Power can be increased and the bottling can be reduced, but since the ink adhering to the tip of the outer surface of the ball holder cannot be reduced to zero, the adhering ink cannot be prevented from gradually accumulating as priming water, and It has not been solved.
In addition, as described in Patent Documents 3 and 4, the ink is given shear thinning to lower the ink viscosity at the time of writing, so that the ink can easily penetrate into the paper. The excess ink is allowed to permeate into the paper, so that less ink tends to run on the outer surface of the ball holder, and as a result, the amount of waste can be reduced, but the relative amount decreases. This alone does not solve the fundamental problem, but does not completely eliminate the problem.
In addition, because of its low viscosity and easy penetration, the handwriting is remarkably blurred or the ink whose viscosity has been lowered moves without acting as a cushioning material between the ball and the inner wall of the ball holder. In some cases, the frictional resistance is increased by direct contact with the surface of the ball, and the rotation of the ball is obstructed.
The present invention improves the disadvantages of such conventional oil-based ballpoint pen inks, can reduce bottling, and gives a light writing taste by suppressing physical contact between the ball and the ball seat. It aims at providing the ink for ball-point pens.

That is, the first gist of the present invention is an oil-based ink for ballpoint pens comprising at least a cyclohexanone-ketone resin and ethylene glycol monopropyl ether.
The second gist of the present invention is an oil-based ink for ballpoint pens in which the cyclohexanone-ketone resin has a weight average molecular weight in the range of 1000 or more and less than 3000.
Furthermore, the third gist is an oil-based ink for ballpoint pens in which the addition amount of the cyclohexanone-ketone resin of the second gist is in the range of 9.0 wt % or more and less than 15.0 wt %.

  When cyclohexanone-ketone resin and ethylene glycol monopropyl ether are used in combination, the hydrogen of the hydroxyl group of ethylene glycol monopropyl ether is hydrogen-bonded to the oxygen of the ketone group present at almost equal intervals in the main chain of cyclohexanone-ketone resin, The propyl group of ethylene glycol monopropyl ether forms a stable complex by hydrophobic bonding with the carbon of the six-membered ring of the ketone resin. This complex of cyclohexanone-ketone resin and ethylene glycol monopropyl ether has a certain thickness because it contains ethylene glycol monopropyl ether inside, and is a ketone arranged at almost equal intervals in the main chain of cyclohexanone-ketone resin. The ether bond of the group or ethylene glycol monopropyl ether is polarized and negatively charged, and has a property of being easily bonded to a metal, and adheres not only to the inner wall of the ball holder but also to the small edge portion of the ball holder.

The complex of cyclohexanone-ketone resin and ethylene glycol monopropyl ether attached in the vicinity of the forehead forms a layer having a high polymer concentration by evaporation of ethylene glycol monopropyl ether, which is a relatively low boiling point solvent. This layer having a high polymer concentration generates strong electrostatic repulsion against the polymer in the ink existing in the surrounding area, and further, the hydrodynamic interaction and the excluded volume effect are reduced. Since the attractive force with the polymer existing outside the layer having a high concentration is small, the ink newly supplied near the forehead by the rotation of the ball repels the above-mentioned composite layer and further increases. It is inferred that the accumulation state was not formed, and the bottling was suppressed.
In addition, if the propyl group of ethylene glycol monopropyl ether is substituted with a methyl group or an ethyl group, the hydrophobicity is too weak and the hydrophobic bond with the ketone resin is insufficient, and if it is a butyl group, the steric hindrance is large. A stable complex cannot be formed, and since the swelling of the polymer is insufficient, the spread of the polymer is small, sufficient electrostatic repulsion cannot be exerted, and the suppression of the void is insufficient.

  Further, the composite of the above-described cyclohexanone-ketone resin and ethylene glycol monopropyl ether forms a thick adsorption layer uniformly on the metal surface of the ball or chip, thereby suppressing physical contact between the ball and the ball seat. For this reason, it is guessed that the lubricating effect can be exhibited efficiently and a light writing taste can be maintained.

The invention is described in detail below.
Examples of the cyclohexanone-ketone resin include Hilac 901, 111 and 222 (manufactured by Hitachi Chemical Co., Ltd.), ketone resin K-90 (manufactured by Arakawa Chemical Co., Ltd.), and the like. Preferably, those having a weight average molecular weight in the range of 1000 or more and less than 3000, the viscosity of which does not increase easily even when the amount added to the ink is increased, are used. Moreover, the usage-amount can be used in 0.5-20.0 weight% or less with respect to the ink composition whole quantity, Preferably it is less than 9.0-15.0 weight%. If the amount is 0.5% by weight, the anti-fogging effect cannot be obtained, and if it exceeds 20.0% by weight, there is a possibility that the viscosity of the ink becomes high and the ink discharge from the pen tip becomes worse.

  The addition amount of ethylene glycol monopropyl ether can be used in the range of 0.1 to 50.0% by weight or less, preferably 3.0 to 30.0% by weight or less based on the total amount of the ink. If the amount is less than 0.1% by weight, the effect of preventing blur is not obtained, and if it exceeds 50.0% by weight, there is a possibility that the writing quality becomes heavier due to an increase in solid content over time.

As long as the organic solvent is used in combination with ethylene glycol monopropyl ether, any solvent that is usually used in oil-based inks for ballpoint pens can be used.
Specific examples include propylene glycol, hexylene glycol, ethylene glycol mononormal butyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl. Ether, dipropylene glycol dimethyl ether, phenyl cellosolve, benzyl alcohol, dipropylene glycol, propylene glycol monophenyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, tri B propylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monobutyl ether, isobutyl diglycol, phenyl diglycol, phenyl triglycol, benzyl glycol, benzyl di glycol, benzyltrimethylammonium glycol.

  As the colorant, generally used dyes and pigments can be used. Examples of dyes include SPILON BLACK GMH SPECIAL, SPILON RED C-GH, SPILON RED C-BH, SPILON BLUE C-RH, SPILON BLUE BPNH, SPILON YELLOW C-2GH, SPILON VIOLET C-RH, S. P. T. T. et al. ORANGE6, S. P. T. T. et al. Eisenspiron color such as BLUE111 (manufactured by Hodogaya Chemical Co., Ltd.), Eisen SOT dye, ORIENT SPRIT BLACK AB, VALIFAST BLACK 3804, VALIFAST RED 1320, VALIFAST RED 1360, VALIFAST ORANGE ST VALIFAST BLUE 1601, VALIFAST BLUE 1603, VALIFAST BLUE 1621, VALIFAST BLUE 2601, VALIFAST YELLOW 1110, VALIFAST YELLOW 3104, VALIFAST YELLOW 3105, VALIFAST 1105 Balifast color such as (Orient Chemical Co., Ltd.), Orient Oil Color, Rhodamine B Base, Soldan Red 3R, Methyl Violet 2B Base, Victoria Blue F4R, Neo Super Blue C-555 (Chuo Synthetic Chemical Co., Ltd.) Manufactured).

  As the pigment, those generally used can be used. Examples include carbon black, insoluble azo pigments, azo lake pigments, condensed azo pigments, diketopyrrolopyrrole pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, isoindoline pigments, anthraquinone pigments. Conventional organic pigments such as organic pigments such as dioxazine pigments, indigo pigments, thioindigo pigments, quinophthalone pigments, perinone and perylene pigments can be used. These may be used alone or in combination of two or more.

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

In general, the pigment can be dispersed by a general method.
For example, a pigment, ethylene glycol monopropyl ether, and a dispersant are mixed and stirred uniformly with a propeller stirrer or the like, and then the pigment is dispersed with a disperser. A dispersing machine such as a roll mill, a ball mill, a sand mill, a bead mill, or a homogenizer is appropriately selected depending on the amount of solvent of the ink and the pigment concentration.

Cyclohexanone-ketone resin and a resin can be used in combination in the ink composition in order to impart fixability of the handwriting to the writing surface. Specific examples include resins for ink compositions such as phenol resins, ketone resins, and rosin resins.
Specific examples of the resin for the ink composition include phenolic resins such as Tamanol 100S, 510 (above, manufactured by Arakawa Chemical Co., Ltd.), Hitanol 1501, 2501 (above, manufactured by Hitachi Chemical Co., Ltd.), YP. -90, YP-90L, YS Polyster S145, # 2100, # 2115, # 2130, T80, T100, T115, T130, T145, Mighty Ace G125, 150 (above, Yashara Chemical Co., Ltd. )) As ketone resins, Hilac 110H (manufactured by Hitachi Chemical Co., Ltd.), Halon 110H (manufactured by Honshu Chemical), Resin SK (manufactured by Huls), etc., as rosin resins, rosin-modified maleic acid resins, Hercolin D, Pentaline 255, 261, 269, 830 (above, manufactured by Rika Hercules Co., Ltd.), Riester NL, L, MT, MSR-4, Harimac 135G, T-80, FX-25, AS-5, AS-9, Neotol C, Gum Rosin X (above, Harima Chemical Co., Ltd.) ), Gum rosin WW (made in China), ester gum H, Marquide # 30A, # 31, # 32, # 33, # 34 (Arakawa Chemical Industries, Ltd.) and the like.
These resins can be used by mixing with cyclohexanone-ketone resin, and when added for imparting fixability to the writing surface, the amount used is 0.5 to 20.0% by weight based on the total amount of the ink composition. The following is preferred. If the amount is less than 0.5% by weight, the fixability of the handwriting on the writing surface may be insufficient. If the amount exceeds 20.0% by weight, the viscosity of the ink increases and the ink discharge from the pen tip becomes worse. there is a possibility.

  In addition to the above components, various additives such as surfactants and rust inhibitors that are conventionally used in ink compositions can be used as needed. Examples of surfactants include polyoxyethylene alkyl ether, sorbitan fatty acid ester, polyoxyethylene sorbit fatty acid ester, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene fatty acid ester, polyoxyethylene polyoxypropylene alkyl Examples include ether, polyoxyethylene alkylamine, and polyoxyethylene alkyl ether phosphoric acid. Examples of the rust inhibitor include benzotriazole, cyclohexylammonium chloride, 2-mercaptobenzotriazole, benzoylaminocaproic acid, and calcium nitrate.

  In order to produce the ink, the dye, the pigment dispersed above, the cyclohexanone-ketone resin and ethylene glycol monopropyl ether are sufficiently mixed and stirred with a stirrer such as a homomixer, and then other components such as a viscosity modifier. It is obtained by mixing oil, dyes for adjusting color tone, lubricants, etc., and further dissolving and mixing until uniform. In some cases, the mixed ink may be further dispersed by a disperser. There is no problem with removing the coarse particles and insoluble components by filtering or centrifuging the ink.

  Hereinafter, it demonstrates still in detail based on an Example and a comparative example. In each example, “part” simply means “part by weight”.

Example 1
Ethylene glycol monopropyl ether 26.7 parts Diethylene glycol monomethyl ether 30.3 parts Phenyl cellosolve 10.9 parts Printex 35 (carbon black, manufactured by Degussa Huls Japan Co., Ltd.)
10.8 parts SPILON BLUE C-RH (oil-based dye, Hodogaya Chemical Co., Ltd.) 4.7 parts SPILON RED C-BH (oil-based dye, Hodogaya Chemical Co., Ltd.) 5.8 parts VALIFAST YELLOW 1109 (oil-based dye, manufactured by Orient Chemical Co., Ltd.)
3.2 parts Hilac 901 (cyclohexanone-ketone resin, manufactured by Hitachi Chemical Co., Ltd.) (weight average molecular weight: 2400) 5.0 parts ESREC BL-1 (polyvinyl butyral, dispersant, manufactured by Sekisui Chemical Co., Ltd.) )
1.6 parts ESREC BH-3 (polyvinyl butyral, viscosity modifier, manufactured by Sekisui Chemical Co., Ltd.)
1.0 part Of the above components, the total amount of diethylene glycol monomethyl ether and the total amount of S-Rec BL-1 were stirred and mixed and dissolved at 70 ° C., then allowed to cool to room temperature, and then the total amount of Printex 35 was added to the dyno mill. Using a zirconia bead having a diameter of 0.3 mm with a bead mill (manufactured by Shinmaru Enterprise Co., Ltd.), 10 passes were performed to obtain a black paste.
Next, the total amount of ethylene glycol monopropyl ether, the total amount of phenyl cellosolve, the total amount of SPILON BLUE C-RH, the total amount of SPILON RED C-BH, the total amount of VALIFAST YELLOW 1109, the total amount of Hilac 901, The total amount of SREC BH-3 was added, and the mixture was stirred and mixed at 70 ° C. for 3 hours, and then allowed to cool to room temperature to obtain a black ballpoint pen ink.

(Example 2)
Ethylene glycol monopropyl ether 13.3 parts Diethylene glycol monomethyl ether 34.4 parts Diethylene glycol dimethyl ether 15.2 parts Pigment Red 2 11.1 parts VALIFAST YELLOW 1109 (oil-based dye, manufactured by Orient Chemical Co., Ltd.)
5.6 parts SPILON RED C-GH (oil-based dye, manufactured by Hodogaya Chemical Co., Ltd.) 8.2 parts Hilac 901 (cyclohexanone-ketone resin, manufactured by Hitachi Chemical Co., Ltd.) 9.1 parts PVP K- 90 (polyvinyl pyrrolidone, manufactured by Nippon Shokubai Co., Ltd.) 1.5 parts ESRECK BL-1 (polyvinyl butyral, dispersant, manufactured by Sekisui Chemical Co., Ltd.) 1.6 parts Among the above components, the total amount of diethylene glycol monomethyl ether and After stirring and mixing and dissolving the entire amount of ESREC BL-1 at 70 ° C., the mixture was allowed to cool to room temperature, and then the entire amount of Pigment Red 2 was added, and the diameter was reduced to 0. 0 mm with a Dino mill (bead mill, manufactured by Shinmaru Enterprise Co., Ltd.). Using 3 mm zirconia beads, 10 passes were performed to obtain a red paste.
Next, the total amount of ethylene glycol monopropyl ether, the total amount of diethylene glycol dimethyl ether, the total amount of VALIFAST YELLOW 1109, the total amount of SPILON RED C-GH, the total amount of Hilac 901, and the total amount of PVP K-90 were added to this paste. The mixture was stirred and mixed at 70 ° C. for 3 hours and then allowed to cool to room temperature to obtain a red ballpoint pen ink.

Example 3
Ethylene glycol monopropyl ether 22.4 parts Diethylene glycol monomethyl ether 22.2 parts Phenyl cellosolve 8.8 parts Pigment Blue 9 13.5 parts VALIFAST RED # 1320 (oil-based dye, manufactured by Orient Chemical Co., Ltd.)
3.5 parts VALIFAST BLUE # 1605 (oil-based dye, manufactured by Orient Chemical Co., Ltd.)
12.0 parts Hilac 901 (cyclohexanone-ketone resin, manufactured by Hitachi Chemical Co., Ltd.) 15.0 parts ESREC BL-1 (polyvinyl butyral, dispersant, manufactured by Sekisui Chemical Co., Ltd.)
1.6 parts ESREC BH-3 (polyvinyl butyral, viscosity modifier, manufactured by Sekisui Chemical Co., Ltd.)
1.0 part Among the above components, the total amount of diethylene glycol monomethyl ether and the total amount of S-Rec BL-1 were stirred, mixed and dissolved at 70 ° C., then allowed to cool to room temperature, and then added with the total amount of Pigment Blue 9 to add dynomill ( Using a zirconia bead having a diameter of 0.3 mm with a bead mill (manufactured by Shinmaru Enterprise Co., Ltd.), 10 passes were performed to obtain a blue paste.
Next, the total amount of ethylene glycol monopropyl ether, the total amount of phenyl cellosolve, the total amount of VALIFAST RED # 1320, the total amount of VALIFAST BLUE # 1605, the total amount of Hilac 901, and the total amount of ESREC BH-3 were added to this paste. The mixture was stirred and mixed at 70 ° C. for 3 hours and then allowed to cool to room temperature to obtain a blue ballpoint pen ink.

Example 4
Ethylene glycol monopropyl ether 19.0 parts Diethylene glycol monomethyl ether 30.0 parts Diethylene glycol dimethyl ether 8.6 parts Phenylcellosolve 5.9 parts SPILON RED C-GH (oil-based dye, manufactured by Hodogaya Chemical Co., Ltd.) 5.6 parts SPILON RED C-BH (oil-based dye, manufactured by Hodogaya Chemical Co., Ltd.) 6.2 parts VALIFAST YELLOW 1109 (oil-based dye, manufactured by Orient Chemical Industries, Ltd.)
3.5 parts Hilac 901 (cyclohexanone-ketone resin, manufactured by Hitachi Chemical Co., Ltd.)
20.0 parts ESREC BH-3 (polyvinyl butyral, viscosity modifier, manufactured by Sekisui Chemical Co., Ltd.)
1.0 part The above components were stirred at 70 ° C. and dissolved uniformly to obtain a red ballpoint pen oil-based ink.

(Example 5)
In Example 3, the same procedure was followed except that Hilac 901 was removed and Hilac 111 (cyclohexanone-ketone resin, manufactured by Hitachi Chemical Co., Ltd.) (weight average molecular weight: 3200) was added accordingly. An oil-based ink was obtained.

(Example 6)
In Example 3, the same procedure was followed except that Hilac 901 was removed, and Hilac 222 (cyclohexanone-ketone resin, manufactured by Hitachi Chemical Co., Ltd.) (weight average molecular weight: 3200) was added accordingly. An oil-based ink was obtained.

(Example 7)
In Example 3, the same procedure was performed except that Hilac 901 was removed, and ketone resin K-90 (cyclohexanone-ketone resin, manufactured by Arakawa Chemical Industries, Ltd.) (weight average molecular weight: 700) was added accordingly. An oil-based ink for ballpoint pens was obtained.

(Comparative Example 1)
The same procedure as in Example 3 was performed except that ethylene glycol monopropyl ether was removed and benzyl alcohol was added correspondingly, thereby obtaining a blue oil-based ink for ballpoint pens.

(Comparative Example 2)
In Example 3, the same procedure was followed except that ethylene glycol monopropyl ether was removed and diethylene glycol dimethyl ether was added correspondingly to obtain a blue oil-based ink for ballpoint pens.

(Comparative Example 3)
The same procedure as in Example 3 was performed except that ethylene glycol monopropyl ether was removed and xylene glycol was added to that amount to obtain a blue oil-based ink for ballpoint pens.

(Comparative Example 4)
In Example 2, Hilac 901 was removed, 6.2 parts of Hitanol 1501 (phenol resin, manufactured by Hitachi Chemical Co., Ltd.), and Super Becacite 1001 (phenol resin, manufactured by Dainippon Ink & Chemicals, Inc.) The procedure was the same except that 2.9 parts was added to obtain a red ballpoint pen-based oil-based ink.

(Comparative Example 5)
In Example 2, Hilac 901 was pulled out, and Superbecasite 1001 (phenol resin, manufactured by Dainippon Ink & Chemicals, Inc.) 3.8 parts, Ester gum H (hydrogenated rosin ester, Arakawa Chemical Co., Ltd.) Manufactured in the same manner as above except that 5.3 parts were added to obtain a red oil-based ink for ballpoint pens.

(Comparative Example 6)
In Example 2, the same procedure was performed except that Hilac 901 was removed and EGC-1720 (fluorine resin, manufactured by Sumitomo 3M Co., Ltd.) was added accordingly, to obtain a red oil-based ink for ballpoint pens.

(Comparative Example 7)
In Example 2, Hilac 901 was pulled out, and 5.0 parts Harrier Star L (rosin-modified glycerin ester, manufactured by Harima Chemical Co., Ltd.), Harimac T-80 (Rosin modified maleic acid, manufactured by Harima Chemical Co., Ltd.) Was added in the same manner except that 4.1 parts were added to obtain a red oil-based ink for ballpoint pens.

(Comparative Example 8)
In Example 2, the same procedure was followed except that Hilac 901 was removed, and Hilac 110H (acetophenone ketone resin, weight average molecular weight: 1500, manufactured by Hitachi Chemical Co., Ltd.) was added accordingly. An oil-based ink was obtained.

(Production of oil-based ballpoint pen for testing)
The oil-based ink for ballpoint pens obtained in Examples 1 to 6 and Comparative Examples 1 to 3 is applied to a writing instrument having the same structure as a commercially available oil-based ballpoint pen (VICUNA, product code BX157, manufactured by Pentel Co., Ltd. (ball diameter φ0.7)). 0.2 g was filled, and a centrifugal force (1000 rpm, 5 minutes) was applied in a centrifuge to degas bubbles in the ink, thereby preparing a test ballpoint pen.

  Bottling test: The number of punctures generated on the paper surface when 50 hiragana letters were repeatedly written on one sheet of manuscript paper (made by KOKUYO Co., Ltd., product number: Key-10) at 400 o'clock was counted. The results are shown in Table 1.

Measurement of writing resistance value: n = 3 test ballpoint pens containing the inks of the above-mentioned examples and comparative examples were tested at Tribo-master (Type: TL201Sa) manufactured by Trinity Lab. After the creation, the writing resistance value of beautiful writing was measured. When the writing resistance value was measured, the writing angle was 70 °, and other conditions were a writing load of 150 g and a writing speed of 7 cm / sec.
For the measurement of the writing resistance value, the sum of the values in each plot of the data measured for 2 seconds at a measurement frequency of 200 Hz (200 plots per second) is divided by the total number of plots (400 plots / 2 seconds) and averaged. The average writing resistance value for the specimen was calculated as the value. Furthermore, n = 3 average values were calculated from the average writing resistance values for the five specimens, and used as the writing resistance values of the test ballpoint pens using the examples and comparative examples.

Sensory test of writing taste (lightness of writing taste, smoothness): A writing sensory test by handwriting was performed by 20 monitors, and the writing taste in an unwritten state was evaluated.
Evaluation criteria are heavy or not smooth (1 point), light but not smooth or smooth but heavy (2 points), light and smooth (3 points), very light and smooth (4 points), 20 The average value of people was calculated.

  Since the ink composition for ballpoint pens of Examples 1 to 7 uses cyclohexanone-ketone resin and ethylene glycol monopropyl ether in combination, it has a high adsorptivity to the metal surface of a stable complex and has a light writing quality. Further, the ink newly supplied to the vicinity of the fore edge by the rotation of the ball repels the above-mentioned composite layer and no further accumulated state is formed, and the effect of preventing the blur is obtained.

  Moreover, since the ink composition for ball-point pens of Examples 2 and 3 used cyclohexanone-ketone resin and ethylene glycol monopropyl ether in a preferred addition amount, a stronger anti-bottom effect and lighter writing taste were obtained. .

On the other hand, since the ink compositions for ballpoint pens of Comparative Examples 1 to 3 do not use ethylene glycol monopropyl ether, there is no solvent that forms a stable complex with the cyclohexanone-ketone resin, so that the anti-bottle effect is achieved. I can't get it.
It is surmised that the ink compositions for ballpoint pens of Comparative Examples 4 to 7 have no anti-blading effect in the added resin.
As described above in detail, the ink for ballpoint pens of the present invention relates to a ballpoint pen ink composition that can reduce ink blur when written with a ballpoint pen, and further provides a light and smooth writing feel. It is.

Claims (3)

An oil-based ink for ballpoint pens comprising at least cyclohexanone-ketone resin, a colorant, and ethylene glycol monopropyl ether. The oil-based ink for ballpoint pens according to claim 1, wherein the cyclohexanone-ketone resin has a weight average molecular weight in the range of 1000 or more and less than 3000. The oil-based ink for ballpoint pens according to claim 2, wherein the addition amount of cyclohexanone-ketone resin is in the range of 9.0 wt% or more and less than 15.0 wt% .