JP2008133385A - Ink composition for ball-point pen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an ink composition for ball-point pen excellent in writing feeling without changing viscosity and rheology performance of ink even in passage of high-humidity long period. <P>SOLUTION: The ink composition for ball-point pen comprises a coloring material, a resin, a compound represented by the general formula, an additive selected from diethylene glycol dibutyl ether, triethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink composition for ballpoint pens that does not cause writing failure or blur due to a change in ink viscosity when writing after long-term storage, particularly after long-term storage under high humidity conditions, and has excellent writing feeling. .

  Conventionally, as a ballpoint pen ink with a light writing feel, the invention described in JP-A-2002-003772 (Patent Document 1) contains 1 to 5% of a pigment and a high molecular weight polyvinylpyrrolidone having a molecular weight of 250,000 or more as a resin. An ink having an ink viscosity of 1.5 Pa · s or less is disclosed.

Further, assuming that ink leakage occurs when the ink viscosity is lowered, the invention described in JP-A-8-311388 (Patent Document 2) contains a colorant, a solvent, a non-Newtonian viscosity imparting agent, and a non-Newtonian viscosity index. An oil-based ballpoint pen ink having a viscosity of 0.2 to 0.92 and a viscosity at a shear rate of 500 s ⁻¹ of 1000 to 10,000 mPa · s is disclosed.

The invention described in Japanese Patent Application Laid-Open No. 2004-107596 (Patent Document 3) includes a coloring material, a resin, 0.01 to 1.5% by weight of a high polymerization degree polyvinyl butyral having a polymerization degree of 900 or more and a specific solvent. Ink has been disclosed in which smooth writing feeling can be obtained while suppressing blur.
JP 2002-003772 A JP-A-8-311388 JP 2004-107596 A

  Conventionally, resins used for the purpose of fixing handwriting, adjusting viscosity, dispersing pigment, etc., absorb ink by long-term storage, especially storage at high humidity, and the water causes insolubilization and precipitation of the resin, resulting in viscosity. There may be problems such as leakage due to lowering, tracking and poor writing due to pigment aggregation. In particular, for the purpose of lightening the writing quality, an ink having a low viscosity as in the invention described in Patent Document 1 or imparted with properties such as non-Newtonian viscosity as in the invention described in Patent Document 2 Since the rheological performance is set within a narrow range to balance the performance such as writing quality and leakage, it was exhibited at the beginning of production due to changes in viscosity and rheological performance even if the amount of moisture absorbed was small. The balance between the performance of writing taste and omission, writing taste and handwriting loss, etc. will be lost, and the effect of frequent leakage and handwriting will appear.

  In the invention described in Patent Document 3, it is widely used in general oil-based ballpoint pens to solve the problem of moisture absorption, and is effective in preventing leakage and blistering, but also has high hygroscopicity and causes a decrease in viscosity due to moisture. By using high polymerization degree polyvinyl butyral with low hygroscopicity instead of much polyvinyl pyrrolidone, the viscosity of the ink is prevented from being lowered and the occurrence of squeeze is suppressed. In addition to high polymerization degree polyvinyl butyral, viscosity adjustment and pigment dispersion For this purpose, other types of resins are used. For such resins, a decrease in viscosity due to moisture absorption and a decrease in pigment dispersion performance due to precipitation are unavoidable, and the effect is not sufficient.

  The purpose of the present invention is to suppress changes in viscosity and rheological performance due to insolubilization and precipitation of the resin, and poor pigment dispersion, even after long-term storage, particularly after storage at high humidity, regardless of the type of resin used. It is an object of the present invention to provide a ballpoint pen ink composition that does not cause disability or blurring and retains the original writing quality, leakage prevention, and anti-blading performance of the ink composition.

  The present invention includes a colorant, a solvent, a resin, at least one compound represented by the following general formula (Formula 1) as additive A, and diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, tetraethylene as additive B The gist of the present invention is a ballpoint pen ink composition containing one or more selected from glycol dimethyl ether.

The present invention is an ink composition for ball-point pens that does not cause inability to write or blur due to a change in ink viscosity during writing after long-term storage, particularly after long-term storage under high humidity conditions, and has excellent writing feeling.
In the present invention, the diglycerin polyoxypropylene addition derivative of m + n + o + p = 14-30, which is additive A, has the effect of stabilizing the dissolution of the resin in the ink as compared with other solvents, but in addition, it has a branched structure. It is considered that the water content in the ink is incorporated into the structure by a relatively large molecular weight, and the influence of the water content on the dissolved resin is suppressed. At least one glycol diether selected from diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether as additive B has a very high effect of suppressing moisture absorption into the ink. It is an additive that is poor in compatibility and may cause a decrease in viscosity due to insolubilization of the resin over a long period of time. However, when used in combination with additive A, the ink can be prevented from absorbing moisture without adversely affecting the solubility of the resin.

  In addition, by using a high molecular weight resin and the like to give a special rheological performance such as shear thinning by using a blending ratio (A / B) of additive A and additive B of 1 or more and 2 or less. In contrast, it is possible to obtain an ink with little change in ink performance during moisture absorption, which can achieve both sufficient resin dissolution stability and moisture absorption prevention. When A / B is 1 or less, the effect of the resin A by the additive A is insufficiently stable, and the resin may be partially insolubilized. Therefore, the resin and wax for rheological performance addition may become unstable and the predetermined rheological performance may not be exhibited. If the A / B is 2 or more, the ink viscosity will increase so that the performance of writing lines such as line cracking will be reduced. May have an impact.

The compound represented by the above general formula (Formula 1) as additive A is a kind of ether polyol obtained by addition polymerization of propylene oxide to diglycerin. In the above general formula (Formula 1), m, n, o and p are all integers indicating the number of repetitions of “C ₃ H ₆ O”. The total value of these m + n + o + p is 14 or more and 30 or less. In addition, the substance of the combination from which the value of m, n, o, p of this compound differs may be mixed.
The compounding amount of this compound is 1% by weight to 30% by weight, preferably 5% by weight to 20% by weight, based on the total amount of the ink composition. These compounds may be used alone or in combination of two or more. The total amount is preferably in the above range. These additions may be carried out in any process of ink production. For example, when a dye is heated and dissolved by stirring, a process of dispersing a pigment may be performed, or even when preparing an ink composition together with other additives. Good.

Together with additive A, additive B is used in combination with one or more selected from diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, and glycol diether of tetraethylene glycol dimethyl ether. The blending amount of the additive B is 1% by weight to 15% by weight, preferably 5% by weight to 10% by weight, based on the total amount of the ink composition, and the total amount of the compounds shown as the additive B is within the above range. Preferably there is.
Further, the additive A, additive B and other blends may be added in any process of ink production, and these additive A and additive B may be added separately. For example, when the dye is heated and dissolved with stirring, it may be a step of dispersing a pigment, or may be a time of preparing an ink composition together with other additives. Furthermore, the blending ratio (A / B) of the additive A and the additive B is desirably 1 or more and 2 or less.

As the colorant used in the present invention, both dyes and pigments conventionally used in ballpoint pen inks can be used without limitation.
As the dye, acid dyes, basic dyes, metal complex dyes, salt-forming dyes, azine dyes, anthraquinone dyes, phthalocyanine dyes, triphenylmethane dyes and the like can be used. Specifically, Bali First Yellow # 3104 (C.I. 13900A), Bali First Yellow # 3105 (C.I. 18690), Orient Spirit Black AB (C.I. 50415), Bali First Black # 3804 (C.I. 12195), Bali First Yellow # 1109, Bali First Orange # 2210, Bali First Red # 1320, Bali First Blue # 1605, Bali First Violet # 1701, Orient Oil Scarlet # 308, Nigrosine Base EX-BP (above, oil-based dyes manufactured by Orient Chemical Industry Co., Ltd.) , SPIRON black GMH Special, SPIRON yellow C-2GH, Spiron Red C-GH, Spiron Red C-BH, Spiron Blue BPNH, Spiron Blue C-RH, SPIRON Violet C-RH, S. P. T.A. Orange 6, S. P. T.A. Blue-111 (oil dye manufactured by Hodogaya Chemical Co., Ltd.), Rhodamine B base (CI. 45170B, oil dye manufactured by Sumitomo Chemical Co., Ltd.), Victoria Blue F4R, Nigrosine Base LK (Germany) Country, B.A.S.F.), Methyl Violet 2B base (American National Div.) Can be used.

  Pigments include insoluble azo pigments, azo lake pigments, condensed azo pigments, diketopyrrolopyrrole pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, isoindoline pigments, anthraquinone pigments, dioxazine pigments, Organic pigments such as indigo pigments, thioindigo pigments, quinophthalone pigments, perinone, perylene pigments, inorganic pigments such as iron oxide, carbon black, titanium oxide, cadmium red, chrome yellow, cadmium yellow, ultramarine blue, and bitumen, and fluorescent pigments In addition, pigments with resin particles colored with dyes that do not dissolve in the ink solvent can be used, and the pigment surface is treated in advance with an activator, resin, pigment derivative, etc. to stabilize pigment dispersion and control crystallization. You may have done. In addition, conventionally known dyes can be used in combination for color tone adjustment and density improvement. Specific examples of the pigment include the following.

Carbon black can be used as the black pigment. Both channel and furnace carbon black can be suitably used. An example of carbon black is Mitsubishi Carbon Black # 10B, # 20B, # 30, # 33, # 40, # 44, # 45, # 45L, # 50, # 55, # 95, # 260, # 900, # 1000, # 2200B, # 2300, # 2350, # 2400B, # 2650, # 2700, # 4000B, CF9, MA8, MA11, MA77, MA100, MA220, MA230, MA230, MA600 and MCF88 (above, manufactured by Mitsubishi Chemical Corporation), Monarch 120, Monarch 700, Monarch 800, Monarch 880, Monarch 1000, Monarch 1100, Monarch 1300 , Monarch 1400, Mogal L, Legal 99R, Legal 250R, Legal 300R, Legal 330R Legal 400R, Legal 500 and Legal 660R (above Cabot), Printex A, Printex G, Printex U, Printex V, Printex 55, Printex 140U, Printex 140V, Printex 45, Printex 40 , Printex 60, Printex 300, Printex 30, Printex 35, Special Black 4, Special Black 4A, Special Black 5, Special Black 6, Special Black 100, Special Black 250, Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color Black S150, Color Black S160 and Color Black S 70 (manufactured by Degussa Japan (Co.)), Raven 5000 ULTRA II, RAVEN2500 Ultra, RAVEN1250, RAVEN760 Ultra (or, Colombia Yan Carbon Co., Ltd.) and the like. Furthermore, in order to improve the dispersibility, dispersion stability, etc. of these carbon blacks, carbon blacks are sometimes used as carbon blacks in which covalent bonds are formed with organic groups having an anionic substituent by various reactions.
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, etc. can be used, but phthalocyanine pigments give particularly clear handwriting. From the crystal stability and dispersion stability in a solvent, C.I. I. Pigment Blue 15: 3 or a pigment derivative treatment type thereof, or C.I. I. Pigment Blue 15: 6 can be preferably used. Examples of pigments capable of obtaining dark handwriting include C.I. I. Pigment Blue 60 is preferred.
Examples of red pigments include C.I. I. Pigment Red 5, 8, 17, 17, 38, 48: 1, 48: 2, 48: 3, 48: 4, 53: 1, 57: 1, 122, the same 144, 146, 166, 170, 177, 202, 207, 211, 213, 254, 255, 264, 270, 272, etc. can be used. Diketopyrrolopyrrole-based C.I. has good light resistance and solvent resistance, and the appearance color becomes clear red when ink is filled in the refill. I. Pigment Red 254, 255 and 264 can be used particularly preferably. Examples of pigments that have good solvent resistance and can obtain dark handwriting include C.I. I. Pigment Red 170 is preferred.
Examples of yellow pigments include C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 55, 81, 83, 79, 93, 94, 95, 97, 109, 110, the same 120, 128, 138, 147, 151, 154, 167, 185, 191 and the like can be used.
Examples of green pigments include C.I. I. Pigment Green 7, 36, 37, etc. can be used, but as a green ink, the ink appearance is clearer when the ink is prepared by the toning of the blue pigment and the yellow pigment or the toning of the blue dye and the yellow pigment. It becomes a composition.

  In order to increase the dispersion efficiency of the pigment, a polymer compound obtained by finely dispersing a pigment in advance may be used. In particular, when such a pigment is used, the pigment can be easily dispersed in the ink production process and can be used as a useful means for production. For example, Microlith Yellow 3G-K, Yellow 4G-K, Yellow 3R-K, Scarlet RK, DPP Red BK, Magenta 5B-K, Violet BK, Blue A3R-K, Blue 4G-K, Green G-K, Black CK, White RK (Pigment finely dispersed in vinyl chloride / vinyl acetate copolymer resin, Ciba Specialty Chemicals Co., Ltd.) Manufactured), IK yellow, IK red, IK blue, IK green, IK black (pigment finely dispersed in vinyl chloride / vinyl acetate resin, manufactured by Fuji Dye Co., Ltd.), Microlith Yellow 2G-T, Yellow 3R- T, the same Brown 5R-T, the same Scarlet RT, the same Red BR-T, Blue GS-T, Green GT, Black CT (pigment finely dispersed in rosin ester resin, manufactured by Ciba Specialty Chemicals), Microlith Yellow 4G-A, Yellow MX-A, Yellow 2R-A, Brown 5R-A, Scarlet RA, Red 2C-A, Red 3R-A, Magenta 2B-A, Violet B-A, Blue 4G-A, Green G-A, Black C-A, White R-A (pigment finely dispersed in ethyl cellulose resin, manufactured by Ciba Specialty Chemicals), L1 / S Yellow NIF, L1 / 8 Red F3RK-70, L1 / 8 violet RN50, L1 / 8 orange 501, L1 / 8 brown 5R, L1 / 8 black MA100, NC790 white (pigment finely dispersed in nitrocellulose resin, manufactured by Taihei Chemicals Co., Ltd.), Renol Yellow GG-HW, Yellow HR-HW, Orange RL-HW, Red FGR- HW, Red HF2B-HW, Red F5RK-HW, Carmine FBB-HW, Violet RL-HW, Blue B2G-HW, Green GG-HW, Brown HFR-HW, Black R-HW, White T-HW (pigment finely dispersed in polyvinyl butyral resin, manufactured by Clariant Japan Co., Ltd.), Fuji AS Black 810, AS Red 575, AS Blue 650, AS Green 737, AS White 165 (Polyvinyl) Pigments finely dispersed in butyral resin, Fuji Dye Co., Ltd.) It is.

  These colorants may be used alone or in combination of two or more. The amount used can be 3 wt% or more and 35 wt% or less based on the total amount of the ink composition. If the amount used is small, the handwriting becomes thin. If the amount is large, the viscosity of the ink composition becomes high, and handwriting unevenness may occur, or the pigment may settle without sufficient dispersion, resulting in a difference in handwriting density.

  The solvent can be used without limitation as long as it is a solvent that can be normally used for ink for ballpoint pens. For example, water, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether , Ethylene glycol monohexyl ether, ethylene glycol mono 2-ethylhexyl ether, ethylene glycol monoallyl ether, ethylene glycol monophenyl ether, ethylene glycol monoether ether solvent such as ethylene glycol monobenzyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, Diethylene glycol monobutyl ether, diethylene Diethylene glycol monoether solvents such as recall monoisobutyl ether, diethylene glycol monohexyl ether, diethylene glycol mono 2-ethylhexyl ether, diethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mononormal butyl ether , Propylene glycol mononormal propyl ether, propylene glycol monophenyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mononormal propyl ether, dipropylene glycol monobutyl ether, dipropylene Recycle monophenyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monobutyl ether, and other propylene glycol monoether solvents, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, Glycerol, glycol-based solvents such as polyethylene glycol, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, 2-ethylhexyl acetate, isobutyl isobutyrate, ethyl lactate, Esters such as lactic acid-n-butyl, benzyl alcohol, β-phenylethyl alcohol, α-methylbenzyl alcohol, lauryl alcohol , Tridecyl alcohol, iso-dodecyl alcohol, alcohol solvents such as isotridecyl alcohol can be used. In particular, an ethylene glycol monoether solvent and / or a diethylene glycol monoether solvent can be suitably used, and these may be used alone or in combination of two or more, and the blending amount is based on the total amount of the ink composition. 1% by weight or more and 50% by weight or less.

  A conventionally known resin that dissolves in an ink solvent can be added as a viscosity modifier, a non-Newtonian viscosity imparting agent, a pigment dispersion aid or a lubricity imparting agent, a dye dissolution accelerator, and a fixing agent on the paper surface. Specifically, acrylic resin, acrylic acid resin, maleic acid resin, copolymer of styrene and maleic acid ester, copolymer of styrene and acrylic acid or its ester, urea resin, polyvinyl butyral, polyvinyl acetal, polyamide resin Polyester resin, alkyd resin, polyurethane resin, epoxy resin, polyvinyl alkyl ether, coumarone-indene resin, polyterpene, rosin resin and its hydrogenated product, ketone resin, terpene-phenol copolymer, polyacrylic acid polymethacrylic acid copolymer Polymer, phenol resin, polyvinylpyrrolidone, polyethylene oxide, N-vinylacetamide, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethylhydroxyethylcellulose and these Such polymers and various derivatives thereof. These resins can be used alone or in combination, and the blending amount is preferably 0.1% by weight or more and 50% by weight or less based on the total amount of the ink composition.

  As the pigment dispersant, a conventionally known pigment dispersant can be used regardless of whether it is a surfactant, a polymeric surfactant or a resin dispersant. The resin dispersants that can be used particularly well include low molecular weight polyvinyl butyral resins, ketone resins, urea resins, copolymers of styrene and acrylic acid or esters thereof, and copolymers of styrene and maleic acid or esters thereof. Examples thereof include styrene-α-methylstyrene-acrylic acid copolymer, polyacrylic acid, vinyl chloride / vinyl acetate copolymer resin, rosin ester resin, ethyl cellulose, and nitrocellulose. In addition to this, there are many types of high molecular weight surfactants in which polar groups are introduced into the molecule to improve pigment dispersion stability, but there are many products depending on the composition and structure of the polymer portion and the type of polar groups. Examples include Solsperse 17000, Solsperse 20000, and Solsperse 27000 manufactured by Lubrizol.

  In addition, antioxidants, ultraviolet absorbers, rust preventives, and other surfactants with lubricating properties used for improving writing properties, handwriting properties, such as fatty acids and salts thereof, can be used as necessary. , Aromatic sulfonates, higher alcohol sulfates, fatty acid sulfates, alkylallyl sulfonates, polyoxyethylene alkyl ether acetic acid or its salts, anionic surfactants, decaglycerin fatty acid esters, hexaglycerin fatty acid esters , Polyoxyethylene alkyl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polio Shiechiren hydrogenated castor nonionic surface active agents such as oil and the like can be preferably used. In particular, since the colorant is a pigment, it is preferable to add a lubricant for preventing wear of the seat and preventing write-off, and sorbitan fatty acid esters and polyoxyethylene phosphate esters can be preferably used.

  The ink composition for a ballpoint pen of the present invention is appropriately selected from a dispersion mixer such as a heating stirrer, a roll mill, a ball mill, a sand mill, a bead mill, and a homogenizer depending on the amount of solvent and the type and concentration of the colorant. Ink composition for ballpoint pens by various methods such as dispersing pigment together with other components, creating pigment dispersion with pigment dispersed with solvent and dispersion resin, and adding and mixing shear thinning agent and additives during ink adjustment. You can get things. In particular, as a pigment dispersion mixer, a roll mill and a bead mill capable of controlling the temperature when the resin and the pigment are dispersed are preferable.

  Ink bases and inks created to keep the average particle size of the pigment within the set value in order to remove insoluble components of the resin and additives in the ink composition and to remove coarse particles of the pigment. It can also be processed with a filter.

  The ink storage part of the writing instrument for storing the ink composition for a ballpoint pen can be made of metal or synthetic resin. If it is made of transparent or translucent synthetic resin, the remaining amount of ink can be specified. In this case, as long as the resin does not dissolve or swell in the ink solvent, any resin that has been conventionally used as an ink container for a ballpoint pen can be used. For example, polyethylene, polypropylene, polyurethane, polyethylene terephthalate, polyethylene naphthalate, copolymers of polyethylene naphthalate and polyethylene terephthalate, polyamide, polyacrylonitrile resin, polyacrylate, ethylene-vinyl alcohol copolymer, fluororesin, etc. Polypropylene can be used favorably from the viewpoint of properties. Further, any molding method such as extrusion molding or injection molding may be used. Particularly, a molded product in which silicone is applied to the inner surface at the time of extrusion molding is suitable as a container having a performance of preventing ink adhesion and having good visibility of the remaining amount of ink. Further, the backflow preventing composition may be filled in the rear end of the ink column in the ink containing portion, or a float may be disposed in the composition.

  Hereinafter, the composition of Examples and Comparative Examples is shown.

Example 1
Spiron Violet C-RH (Coloring material: manufactured by Hodogaya Chemical Co., Ltd.) 15.0% by weight
Bali First Black # 3802 (Coloring material: manufactured by Orient Chemical Industry Co., Ltd.)
10.0% by weight
Ethylene glycol monophenyl ether 40.0% by weight
Compound of general formula (Formula 1) (m + n + o + p = 14) 11.0% by weight
Tetraethylene glycol dimethyl ether 11.0% by weight
Halon 110H (ketone resin: manufactured by Honshu Chemical Co., Ltd.) 8.0% by weight
PVP K-120 (Polyvinylpyrrolidone: manufactured by ISP Japan Co., Ltd.) 2.0% by weight
Oleic acid 3.0% by weight
Components other than the colorant were heated and stirred at 70 ° C. for 4 hours, and then the colorant was added. The mixture was further heated and stirred at 70 ° C. for 4 hours to obtain an ink composition for a black ballpoint pen.

Example 2
NIPex35 (Coloring material: Degussa Japan Co., Ltd.) 30.0% by weight
Solsperse # 20000 (dispersing agent: manufactured by Avicia Co., Ltd.) 8.0% by weight
Ethylene glycol monophenyl ether 18.5% by weight
Benzyl alcohol 4.0% by weight
Compound of general formula (Formula 1) (m + n + o + p = 24) 5.0 wt%
Diethylene glycol dibutyl ether 7.5% by weight
Resin SK (ketone resin: Degussa Japan Co., Ltd.) 15.0% by weight
10% ethylene glycol monophenyl ether solution of PVP K-120 (described above)
10.0% by weight
Nikkor BS-2 (active agent: manufactured by Nikko Chemicals Co., Ltd.) 2.0% by weight
PVP K-120 and ethylene glycol monophenyl ether are heated and stirred at 85 ° C. for 1 hour to prepare a 10% solution of PVP K-120 in advance.
Components other than the above colorant and PVP K-120 solution are heated and stirred at 70 ° C. for 1 hour, then the colorant is added and dispersed with a bead mill for 1 hour, and then the PVP K-120 solution is added and stirred with a propeller stirrer at 70 ° C. for 3 hours. Thus, an ink composition for a black ballpoint pen was obtained.

Example 3
C. I. PigmentRed254 17.0% by weight
ESREC BL-1 (dispersing agent: manufactured by Sekisui Chemical Co., Ltd.) 4.0% by weight
Benzyl alcohol 23.0% by weight
Tripropylene glycol monobutyl ether 16.0% by weight
Compound of general formula (Formula 1) (m + n + o + p = 14) 13.0 wt%
Diethylene glycol dibutyl ether 9.0% by weight
Resin SK (mentioned above) 13.0% by weight
1 of Denka Butyral # 5000A (polyvinyl butyral: manufactured by Denki Kagaku Kogyo Co., Ltd.)
0% benzyl alcohol solution 2.0% by weight
ECT-3NEX (active agent: manufactured by Nikko Chemicals) 3.0% by weight
Denkabutyral # 5000A and benzyl alcohol are heated and stirred at 80 ° C. for 1 hour to prepare a 10% solution of Denkabutyral # 5000A in advance.
C. I. Components other than Pigment Red 254, Denkabutyral # 5000A 10% benzyl alcohol solution and ECT-3NEX were heated and stirred at 70 ° C. for 45 minutes. I. Pigment Red 254 was added and dispersed with a bead mill for 45 minutes, and then a 10% benzyl alcohol solution of Denkabutyral # 5000A and ECT-3NEX were added and stirred with a propeller stirrer at 60 ° C. for 2 hours to obtain an ink composition for a red ballpoint pen.

Example 4
C. I. PigmentRed254 20.0% by weight
ESREC BL-1 (dispersing agent: manufactured by Sekisui Chemical Co., Ltd.) 4.5% by weight
Ethylene glycol monobenzyl ether 14.5% by weight
Tripropylene glycol monobutyl ether 13.0% by weight
Compound of general formula (Formula 1) (m + n + o + p = 14) 13.0 wt%
Diethylene glycol dibutyl ether 9.0% by weight
Resin SK (mentioned above) 13.0% by weight
3% ethylene glycol monobenzyl ether solution of Crucell H (hydroxypropylcellulose: manufactured by Sanki Co., Ltd.) 10.0% by weight
ECT-3NEX (active agent: manufactured by Nikko Chemicals) 3.0% by weight
Crucell H and ethylene glycol monobenzyl ether are heated and stirred at 85 ° C. for 3 hours to prepare a 3% ethylene glycol monobenzyl ether solution of Crucell H in advance.
C. I. Components other than Pigment Red 254, 3% ethylene glycol monobenzyl ether solution of Crucell H, and ECT-3NEX were heated and stirred at 70 ° C. for 1 hour. I. PigmentRed 254 was added and dispersed with a bead mill for 45 minutes, and then a 3% solution of Crucell H and ECT-3NEX were added and stirred with a propeller stirrer at 60 ° C. for 2 hours to obtain an ink composition for a red ballpoint pen.

Comparative Example 1
In Example 1, a black ballpoint pen ink composition was used in the same manner as in Example 1 except that the total amount of tripropylene glycol monobutyl ether was used instead of the compound of the general formula (Equation 1) and tetraethylene glycol dimethyl ether. Got.

Comparative Example 2
In Example 2, a black ballpoint pen ink composition was obtained in the same manner as in Example 2 except that ethylene glycol monophenyl ether was used instead of the compound of the general formula (Equation 1).

Comparative Example 3
In Example 3, an ink composition for a red ballpoint pen was obtained in the same manner as in Example 3 except that ethylene glycol monophenyl ether was used instead of diethylene glycol dibutyl ether.

Comparative Example 4
An ink composition for a red ballpoint pen was obtained in the same manner as in Example 4 except that instead of the compound of the general formula (Equation 1) and diethylene glycol dibutyl ether in Example 4, the total amount of ethylene glycol monophenyl ether was used. It was.

Preparation of test samples Each ball-point pen ink composition obtained in Examples 1 to 4 and Comparative Examples 1 to 4 was prepared by using a 0.7 mm diameter cemented carbide ball in a stainless steel ball holder and the tip of the ball holder. Knock-type ballpoint pen (Rolly, product code BP127, manufactured by Pentel Co., Ltd.) containing a refill body that connects a ballpoint pen tip held in a state of partially protruding from the opening and a polypropylene pipe formed by extrusion molding 0.25 g of the ink containing tube was filled into a test ballpoint pen sample.
Note that “Rolly (product code BP127)” used in the test ballpoint pen sample has a gap distance between the ballpoint pen tip and the ball at the tip of the ballholder of about 5 μm to 15 μm, preferably about 9 μm. the cross-sectional area of the gap which becomes the discharge port of the ink is 0.01 mm ² or more 0.03 mm ² or less in parts, preferably is adjusted to about 0.018 mm ^2, also impart an impact force to the ball after placement of the ball As a result, a deformation process is performed to transfer the curvature of the ball to the receiving part of the ball holder, and the surface area of the processed part is adjusted to 5% or more and 17% or less, preferably about 11% with respect to the surface area of the ball. It is what.

Initial Viscosity Measurement Using a VAR 100 type rheometer (Jusco International Co., Ltd.), a 1 °, 20 mm cone plate was used, and the ink composition viscosities at temperatures of 25 ° C. and shear rates of 5 s ⁻¹ and 500 s ⁻¹ were measured.

Viscosity measurement after heating with water 5 g of ink composition and 0.25 g of ion-exchanged water are placed in a 20 ml internal screen vial, well agitated and sealed, and the viscosity after 90 hours at 90 ° C. is measured in the same manner as the initial viscosity. .

Written test after humidification 5 ballpoint pen test samples were placed in a constant temperature bath at 40 ° C and 80% for 6 months. 300 m was continuously written on JIS P3201 writing paper A at a speed of 7 cm / sec, a writing angle of 70 degrees, and a load of 150 g, and an average value of the number of vertices on the writing line was calculated and evaluated as follows.
○: Number of blisters is 0 or more and 3 or less Δ: Number of blobs is 4 or more and 15 or less ×: Number of blazes is 16 or more

Short-term follow-up test after humidification lapse of time Each of three ball-point pen test samples was laid in a constant temperature bath at 40 ° C. and 80% for 6 months, and then a commercially available spiral writing tester (MODEL TS-4C-20, manufactured by Seiki Kogyo Laboratories) was used. The writing speed was 14 cm / sec, the writing angle was 70 degrees, the load was 150 g, 300 m was continuously written on JIS P3201 writing paper A, and the writing lines were observed and evaluated as follows.
○: No blurring or line cracking ×: Scratching, line cracking occurred or writing impossible

Rapid leak test after humidification 10 ballpoint pen test samples were placed in a constant temperature bath at 40 ° C and 80% for 6 months, left at 23 ° C for 2 hours, and handwritten on JIS P3201 writing paper A with a diameter of about 2 cm. Write 15 rounds twice. Immediately after that, with the ball holder protruding, do not touch anything at the tip, leave it in a constant temperature bath at 23 ° C and 80% humidity for 1 week, and then repeat the knocking operation 5 times to leak ink from the ball holder and Observe the dirt on the ball holder housing.
○: No leakage: No ink leakage or bleeding on the ball holder △: Leaking: There is ink bleeding on the ball holder, but the exterior is not smudged by the knocking operation.
×: Leakage is large: Ink leakage is large and the exterior is stained by knocking operation.

  As described in detail above, the ink composition for ballpoint pens of the present invention has good writing quality without writing failure or blurring even after aging under high humidity conditions.

Claims (2)

Colorant, solvent, resin, additive A, at least one compound represented by the following general formula (Formula 1), and additive B selected from diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether An ink composition for ballpoint pens comprising one or more of the above.
An ink composition for a ballpoint pen, wherein a blending ratio (A / B) of the additive A and the additive B is 1 or more and 2 or less.