JPH1095948A - Oil-based ink for metal chip type ball point pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject ink which is extremely reduced in leak dripping and is improved in writing smoothness by using an organic solvent, a coloring agent, a resin and an N-vinylcarboxamide. SOLUTION: This ink contains (A) an organic solvent, (B) a coloring agent, (C) an activating agent and (D) an N-vinylcarboxamide resin as essential components. The amount of the component A is preferably 30-70wt.% based on the whole amount of the ink. The amount of the component B is preferably 10-45wt.% based on the whole amount. There are two structures of not- crosslinking type and crosslinking type in the component D and both of them can be selectively used according to the purposes. Thus, an oil-based ball point pen is obtained, as its ink dripping or deposition are extremely reduced during the writing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-based ink for metal-tip ball-point pens, and more particularly to an ink fountain phenomenon (hereinafter referred to as an ink spot) caused by writing.
The present invention relates to an oil-based ink for metal tip ball-point pens that also improves writing taste.

[0002]

2. Description of the Related Art Conventionally, a metal tip ballpoint pen containing an oil-based ink is generally made of an organic solvent, a coloring agent, a resin, and the like, and uses an ink having a viscosity of 7000 to 15000 cps and a relatively high viscosity. At the same time, an oil-soluble polymer was added to increase the viscosity, and a high-concentration dye was used to thicken the handwriting.

[0003] In this case, the viscoelasticity of the ink increases, and the ink exhibits the Weissenberg effect. For this reason, the ink sticks to the rotation of the ball as a writing member, and it becomes difficult to transfer a part or all of the ink on the ball to the paper surface, and the ink is deposited thickly on the rotating ball. The accumulated ink accumulates in the opening of the tip of the ball-point pen tip, and drops to the paper surface at a stage where the ink accumulates to some extent, forming an ink spot. This phenomenon of ink bottling impairs the aesthetics of the handwriting, and also causes a problem that the ink attached to the paper surface by the ink bottling is much harder to dry than the ink in the handwriting portion, and contaminates other things in contact.

[0004] In order to suppress ink bottling, oil-soluble polymers, surfactants and the like are added in various combinations and the like.
Improve the rheological properties of the ink or adjust the viscosity to minimize ink leakage,
It is known that the ink can be more easily transferred from the rotating ball to the paper surface. As an example, there was a method of enhancing spinnability (the balance between elastic modulus and viscosity), but as the spinnability increased, the ink thickened,
There was a drawback that writing taste became worse. Specific additives include oil-soluble polymers such as polyvinylpyrrolidone, rosin, and rosin-modified maleic resin, and surfactants such as oleic acid, polyoxyethylene alkyl ethers, and sorbitan fatty acid esters.

[0005]

However, even with the inks added by various combinations of the above-described oil-soluble polymers, surfactants, etc., the clinging of the ink to the ball is not sufficiently suppressed, and the prevention of ink sticking is not achieved. It was not enough. According to JIS (S6039), a handwriting width that is about 3 to 4 times the normal handwriting (handwriting without ink bottling) is used as the limit size of the ink bottling. The figure in the middle shows that a part of the handwriting having a width of 0.3 mm has a maximum width of 0.8 mm over 5.5 cm. When a writing test was carried out on the ink using the conventional ink, JI
The ink bottling of the size shown in SS6039 is 2
The occurrence of ink spots was not sufficient, and the prevention of ink spots was not satisfactory. An object of the present invention is to obtain an oil-based ink for a ball-point pen having an extremely small amount of ink spots and improved writing taste.

[0006]

That is, the gist of the present invention is an oil-based ink for a metal tip ballpoint pen, comprising at least an organic solvent, a colorant, a resin and an N-vinylcarboxylic acid amide resin.

Hereinafter, the present invention will be described in detail. In the present invention, the organic solvent can be used without any particular limitation as long as it is conventionally used for an oil-based ink for a metal tip ballpoint pen. For example, ethylene glycol monophenyl ether, benzyl alcohol, propylene glycol, dipropylene glycol, 1,3-butylene glycol, Hexylene glycol, tetralin, propylene glycol monophenyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monomethyl ether acetate, tripropylene glycol monomethyl ether, N-methyl-2-
There are pyrrolidone and the like, which can be appropriately selected and used alone or in combination. The use amount is preferably 30 to 70% by weight based on the total amount of the ink. However, it is considered that the electric energy of the tertiary amine or ketone group is involved in the action of the present invention. If the solvent is a polar solvent (eg, water or ethanol), the electric energy of the tertiary amine or ketone group is absorbed. Is not so preferred.

As the colorant, a dye conventionally used in an ink composition for a metal tip oil-based ballpoint pen is mainly used, but a pigment may be used in combination for the purpose of toning and improving handwriting characteristics. Specific examples thereof include, as dyes, rhodamine B base (CI. 45170B), solderan red 3R (CI. 21260), methyl violet 2B base (CI. 42535B), and Victoria blue F4R (CI. 42563B), Nigrosine Base LK (CI. 50415), Balifast Yellow # as an oily dye manufactured by Orient Chemical Industries, Ltd.
3104 (CI. 13900A), Balifast Yellow # 3105 (CI. 18690), Orient Spirit Black AB (CI. 50415), Balifast Black # 3804 (CI. 1219)
5), Balifast Yellow # 1109, Balifast Orange # 2210, Balifast Red # 13
20, Balifast Blue # 1605, Balifast Violet # 1701, Spoilon Black GMH Special, Spiron Yellow C-2GH, Spiron Red C- as oily dyes manufactured by Hodogaya Chemical Industry Co., Ltd.
GH, Spiron Red C-BH, Spiron Blue BPN
H, Spiron Blue C-RH, Spiron Violet C
-RH, S.M. P. T. Orange 6, S.I. P. T. Blue-111 can be exemplified.

As pigments, PRINTEX 95, PRINTEX 7
5, 45, P, XE2, (manufactured by Degussa Japan KK), # 2400B, # 1000, # MCF8
8, MA100, MA7, MA11, # 50, # 40,
# 30, CF9, # 20B (Mitsubishi Kasei Kogyo Co., Ltd.), RAVEN7000, 2000, 12
Carbon blacks such as 00, 1000, 500, 410, and 14 (all manufactured by Columbia Carbon Japan Co., Ltd.), titanium oxides such as P25 (manufactured by Nippon Aerosil Co., Ltd.), black iron oxide, and yellow iron oxide Inorganic pigments such as red iron oxide, ultramarine blue, cobalt blue, chrome green, and chromium oxide, Hansa Yellow 10G, 5G, 3G, 4, GR, A, Benzidine Yellow, Permanent Yellow NCG, Tartrazine Lake, Quinoline Yellow, Sudan 1, Permanent Orange, Indus Ren Brilliant Orange GN, Permanent Brown FG, Para Brown, Permanent Red 4R, Fire Red, Brilliant Carmine 6B, Bordeaux 5B, Thioindigo Red, First Violet B, Dioxane Violet, Arca Blue Lake, phthalocyanine blue, indigo, acid green lake, and organic pigments such as phthalocyanine green. The above-mentioned coloring agents can be used alone or in combination with other ones. The amount of the coloring agents used varies depending on the color tone and the like, but is preferably 10 to 45% by weight based on the total amount of the oil-based ballpoint pen ink composition.
Dyes and pigments can also be used as a mixture.

As the resin added for increasing the ink viscosity or improving the fixing property of handwriting, any resin can be used without particular limitation as long as it is used for oil-based ink for metal tip ballpoint pens. For example, ketone resin, xylene resin, polyethylene oxide, rosin resin, terpene resin, cumarone-indene resin, polyvinyl butyral, polyvinyl pyrrolidone, vinyl pyrrolidone-vinyl acetate copolymer, polymethacrylate, polyacrylic acid poly And methacrylic acid copolymers.

The N-vinylcarboxylic acid amide resin may be used after being mixed with an ink solvent in advance, or may be used after adding another composition of the ink. The ink can be used alone or as a mixture depending on the compatibility and compatibility with other components of the ink.

Various additives and surfactants can be used in the oil-based ink composition for metal tip ball-point pens of the present invention, if necessary, in addition to the above components. Examples include antioxidants, ultraviolet absorbers, rust inhibitors, writability, various surfactants used for improving brushability, such as fatty acid salts,
Anionic surfactants such as higher alcohol sulfates, fatty acid sulfates, alkyl allyl sulfonates, decaglycerin fatty acid esters, hexaglycerin fatty acid esters, polyoxyethylene alkyl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acids Nonionic surfactants such as esters, polyoxyethylene glycerin fatty acid esters, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene alkylphenyl ethers, and polyoxyethylene hydrogenated castor oil.

[0013]

The reason why the oil-based ink composition for a metal tip ball-point pen of the present invention can obtain an oil-based ball-point pen with extremely small ink spots during writing is considered as follows. N
-Vinyl carboxylic acid amide resin is generally compatible with organic solvents, dyes, pigments, and surfactants used in oil-based inks for metal tip ballpoint pens, and has good affinity,
It is considered that the added ink particularly improves the wettability to metal. More specifically, in the case of an oily solvent, the alkyl group in the resin is compatible with the solvent. Therefore, it is considered that the nitrogen and ketone groups are likely to electrically participate in the free electrons of the metal.

The N-vinylcarboxylic acid amide resin has two types of structures, a non-crosslinked type and a crosslinked type. Non-crosslinked N-
Since the ink containing the vinyl carboxylic acid amide resin has an improved elastic modulus, the spinnability due to the thickening of the ink can be improved more than before, and as a result, the increase in the writing load can be suppressed. . The ink to which the cross-linked N-vinylcarboxylic acid amide resin is added has a gel structure. In other words, the force of the ball to rotate during writing lowers the viscosity of the ink close to the ball, and improves the fluidity of the ink, thereby improving transferability to paper. Further, since the ink layer on the ball at the time of writing becomes thinner due to a decrease in the viscosity of the ink, a small amount of the ink that has not been transferred to the paper surface hardly deposits on the ball. As a result, it is unlikely that the ink that cannot enter the gap where the ink is discharged from the tip end opening of the ball-point pen tip is less likely to accumulate, and that an oil-based ball-point pen with extremely small ink spots can be obtained. It is also believed that the improved ink fluidity makes it easier for the ink to follow the ball even when the ball rotation direction changes, and also improves the writing quality.

The crosslinked N-vinylcarboxylic acid amide resin is a microgel (fine particles) of 3 μm or less in a non-polar solvent.
To form Since the gap between the ball and the tip of a general oil-based ball-point pen metal tip is about 5 μm at minimum, the ink is discharged without interruption and the flow stability of the ink is maintained as compared with the case where a larger microgel exists. it is conceivable that.

Hereinafter, the present invention will be described in detail with reference to Examples. However, "parts" indicates parts by weight.

Example 1 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 27.97 parts Benzyl alcohol 27.98 parts Ketone resin 10.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Bali Fast Black 3820 (dye, manufactured by Orient Chemical Industry Co., Ltd.) 20.0 parts Varifast Violet 1701 (dye, manufactured by Orient Chemical Industry Co., Ltd.) 10.0 parts GE191 (non-crosslinked N-vinyl carboxylic acid amide resin) 0.05 parts of the above components were stirred at 80 ° C. for 5 hours to obtain a black ink.

Example 2 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 27.9 parts Benzyl alcohol 28.0 parts Ketone resin 10.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Bali Fast Black 3820 (dye, manufactured by Orient Chemical Industry Co., Ltd.) 20.0 parts Varifast Violet 1701 (dye, manufactured by Orient Chemical Industry Co., Ltd.) 10.0 parts GE191 (non-crosslinked N-vinyl carboxylic acid amide resin) 0.1 parts The above components were stirred at 80 ° C. for 5 hours to obtain a black ink.

Example 3 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 27.8 parts Benzyl alcohol 27.9 parts Ketone resin 10.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Bali Fast Black 3820 (dye, manufactured by Orient Chemical Industry Co., Ltd.) 20.0 parts Varifast Violet 1701 (dye, manufactured by Orient Chemical Industry Co., Ltd.) 10.0 parts GE191 (non-crosslinked N-vinyl carboxylic acid amide resin) 0.3 parts of the above-mentioned components were stirred at 80 ° C. for 5 hours to obtain a black ink.

Example 4 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 27.5 parts Benzyl alcohol 27.5 parts Ketone resin 10.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Bali Fast Black 3820 (dye, manufactured by Orient Chemical Industry Co., Ltd.) 20.0 parts Varifast Violet 1701 (dye, manufactured by Orient Chemical Industry Co., Ltd.) 10.0 parts GE191 (non-crosslinked N-vinyl carboxylic acid amide resin) 1.0 part The above components were stirred at 80 ° C. for 5 hours to obtain a black ink.

Example 5 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 27.0 parts Benzyl alcohol 27.0 parts Ketone resin 10.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Bali Fast Black 3820 (dye, manufactured by Orient Chemical Industry Co., Ltd.) 20.0 parts Varifast Violet 1701 (dye, manufactured by Orient Chemical Industry Co., Ltd.) 10.0 parts GE191 (non-crosslinked N-vinyl carboxylic acid amide resin) 2.0 parts The above components were stirred at 80 ° C. for 5 hours to obtain a black ink.

Example 6 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 28.3 parts Benzyl alcohol 28.4 parts Hexylene glycol 5.0 parts Ketone resin 14.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesqui Oleate 2.0 parts Balifast Blue 1607 (dye, manufactured by Orient Chemical Industry Co., Ltd.) 20.0 parts GE191 (non-crosslinked N-vinylcarboxylic acid amide resin, manufactured by Showa Denko KK) 0.3 parts The ingredients were stirred at 80 ° C. for 5 hours to obtain a blue ink.

Example 7 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 26.3 parts Benzyl alcohol 26.4 parts Butanediol 3.0 parts Ketone resin 13.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquiole Eate 2.0 parts Spiron Red C-GH (Dye, Hodogaya Chemical Industry Co., Ltd.) 12.0 parts Spiron Orange (Dye, Hodogaya Chemical Industry Co., Ltd.) 15.0 parts GE191 (Non-crosslinked N-vinyl) Carboxamide resin (manufactured by Showa Denko KK) 0.3 parts The above components were stirred at 80 ° C. for 5 hours to obtain a red ink.

Example 8 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 27.8 parts Benzyl alcohol 27.9 parts N-methyl-2-pyrrolidone 2.0 parts Ketone resin 15.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Carbon black 18.0 parts Oleic acid 5.0 parts GE191 (Non-crosslinked N-vinylcarboxylic acid amide resin, manufactured by Showa Denko KK) 0.3 parts After stirring for 5 hours, a black ink was obtained.

Example 9 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 26.8 parts Benzyl alcohol 26.9 parts Tetraline 2.0 parts Ketone resin 15.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Cyanine Blue # 4933 (pigment, manufactured by Dainichi Seika Co., Ltd.) 20.0 parts Oleic acid 5.0 parts GE191 (non-crosslinked N-vinylcarboxylic acid amide resin, manufactured by Showa Denko KK) 0 0.3 parts The above components were stirred at 80 ° C. for 5 hours to obtain a black ink.

Example 10 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 27.8 parts Benzyl alcohol 27.9 parts Ketone resin 10.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Bali Fast Black 3820 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 20.0 parts Varifast Violet 1701 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 10.0 parts GX205 (Cross-linked N-vinylcarboxylic acid amide resin, Showa) 0.3 parts of the above components were stirred at 80 ° C. for 5 hours to obtain a black ink.

Example 11 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 27.7 parts Benzyl alcohol 27.8 parts Ketone resin 10.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Bali Fast Black 3820 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 20.0 parts Varifast Violet 1701 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 10.0 parts GX205 (Cross-linked N-vinylcarboxylic acid amide resin, Showa) 0.5 parts of the above components were stirred at 80 ° C. for 5 hours to obtain a black ink.

Example 12 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 27.5 parts Benzyl alcohol 27.5 parts Ketone resin 10.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Bali Fast Black 3820 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 20.0 parts Varifast Violet 1701 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 10.0 parts GX205 (Cross-linked N-vinylcarboxylic acid amide resin, Showa) 1.0 part of the above components were stirred at 80 ° C. for 5 hours to obtain a black ink.

Example 13 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 27.0 parts Benzyl alcohol 27.0 parts Ketone resin 10.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Bali Fast Black 3820 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 20.0 parts Varifast Violet 1701 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 10.0 parts GX205 (Cross-linked N-vinylcarboxylic acid amide resin, Showa) 2.0 parts The above components were stirred at 80 ° C. for 5 hours to obtain a black ink.

Example 14 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 26.0 parts Benzyl alcohol 26.0 parts Ketone resin 10.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Bali Fast Black 3820 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 20.0 parts Varifast Violet 1701 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 10.0 parts GX205 (Cross-linked N-vinylcarboxylic acid amide resin, Showa) 4.0 parts The above components were stirred at 80 ° C. for 5 hours to obtain a black ink.

Example 15 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 25.2 parts Benzyl alcohol 25.3 parts Hexylene glycol 5.0 parts Ketone resin 14.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesqui Oleate 2.0 parts Balifast Blue 1607 (dye, manufactured by Orient Chemical Industry Co., Ltd.) 20.0 parts GX205 (cross-linked N-vinylcarboxylic acid amide resin, manufactured by Showa Denko KK) 0.5 part The components were stirred at 80 ° C. for 5 hours to obtain a blue ink.

Example 16 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 26.2 parts Benzyl alcohol 26.3 parts Butanediol 3.0 parts Ketone resin 13.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquiole Eate 2.0 parts Spiron Red C-GH (dye, manufactured by Hodogaya Chemical Industry Co., Ltd.) 12.0 parts Spiron orange (dye, manufactured by Hodogaya Chemical Industry Co., Ltd.) 15.0 parts GX205 (cross-linked N-vinyl carboxylic acid) Acid amide resin, manufactured by Showa Denko KK 0.5 part The above components were stirred at 80 ° C. for 5 hours to obtain a red ink.

Example 17 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 27.7 parts Benzyl alcohol 27.8 parts N-methyl-2-pyrrolidone 2.0 parts Ketone resin 15.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Carbon black 18.0 parts Oleic acid 5.0 parts GX205 (cross-linked N-vinyl carboxylic acid amide resin, manufactured by Showa Denko KK) 0.5 parts After stirring for an hour, a black ink was obtained.

Example 18 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 26.7 parts Benzyl alcohol 26.8 parts Tetralin 2.0 parts Ketone resin 15.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Cyanine Blue # 4933 (Pigment, manufactured by Dainichi Seika Co., Ltd.) 20.0 parts Oleic acid 5.0 parts GX205 (cross-linked N-vinylcarboxylic acid amide resin, manufactured by Showa Denko KK) 5 parts The above components were stirred at 80 ° C. for 5 hours to obtain a black ink.

COMPARATIVE EXAMPLE 1 K-9 was used instead of GX205 in Example 10.
0 (polyvinylpyrrolidone, manufactured by BASF Co.) was obtained in the same manner as above except that the same amount was added.

Comparative Example 2 K-9 was used in place of Example 11, except that GX205 was omitted.
0 (polyvinylpyrrolidone, manufactured by BASF Co.) was obtained in the same manner as above except that the same amount was added.

Comparative Example 3 Phenyl cellosolve (solvent, ethylene glycol monophenyl ether) 27.6 parts Benzyl alcohol 27.7 parts Ketone resin 10.0 parts Oxyethylene dodecylamine 2.0 parts Sorbitan sesquioleate 2.0 parts Bali First Black 3820 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 20.0 parts Varifast Violet 1701 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 10.0 parts K-90 (Polyvinylpyrrolidone, manufactured by BASF Co.) 0 0.7 parts The above components were stirred at 80 ° C. for 5 hours to obtain a black ink.

[0038]

The oil inks for metal tip ballpoint pens of Examples 1 to 18 and Comparative Examples 1 to 3 are filled into a commercially available metal tip oily ballpoint pen body BK100 (manufactured by Pentel Co., Ltd.) in an amount of 0.25 g. The taste was tested. The results are shown in Tables 1 to 3.

Ink bot count measurement test; writing weight 200
g, at a writing angle of 70 degrees, and at a writing speed of 7 cm / sec, after drawing a spiral on a high-quality paper at a length of 1000 m, the handwriting is written in Scale Lu.
Observation was performed by pe (manufactured by Tokai Sangyo Co., Ltd.), and the number of ink spots on the spiral handwriting was counted.

The ink botts are about 1.5 times the area of a normal handwriting, 0.25 pieces, and those about 3 times more than that are 0.50 pieces, which are equivalent to the ink stipulated in JIS S 6039. Was measured as 1.00, and the total was defined as the number of ink spots. The number of tests is n = 4 and the average value is described.

Surface tension measurement: To compare the wettability with metal, a surface tension meter of Junouy (manufactured by Marubishi Kagaku Kikai Seisakusho)
It measured using.

Measurement of spinnability: 100 in a 100 ml beaker
g of ink was added and the temperature was maintained at 25 ° C. Insert a stainless steel rod with a diameter of 8 mm to a depth of 1 cm
Rotated at 00 rpm. The height of the ink sticking to the stainless steel rod was measured.

Viscosity measurement: The viscosity was measured using an E-type viscometer (manufactured by Tokimec Co., Ltd.) at a temperature of 25 ° C. and a rotor rotation speed of 10 rpm. In Examples 10 to 18, the rotor rotation speed was 1 rpm.

Writing taste (writing load) test; perpendicular to the writing direction when writing a straight line on high quality paper at a pen tip vertical load of 100 g, a writing angle of 70 degrees and a writing speed of 4 cm / sec. The force applied in the opposite direction was measured and defined as the writing load. The number of tests n = 10 and the average value is described.

[0045]

[Table 1] * 1 unit; dyne / cm

[0046]

[Table 2] * 1 unit; dyne / cm

[0047]

[Table 3] * 1 unit; dyne / cm

As described above, the oil-based ink for a metal tip ball-point pen of the present invention has an extremely small amount of ink spots and a good writing taste.

Claims (1)

[Claims] 1. An oil-based ink for a metal ballpoint pen comprising at least an organic solvent, a colorant, an activator and an N-vinylcarboxylic acid amide resin.