JPH11310742A - Water-base ball-point pen ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink which can give a ball-point pen in which the ink delivery is assured in virtue of the ability of the ink to protect the socket from being worn or deformed by the revolving ball by using water, a colorant, a crosslinked poly-N-vinylcarbotylic acid amide, and an N-acylamino acid (salt) as the essential components. SOLUTION: This ink essentially consists of water; a colorant; desirably, 0.1-15.0 wt.%, based on the total amount of the ink, crosslinked poly-N- vinylcarboxylic acid amid (e.g. crosslinked poly-N-vinylacetamide) desirably prepared by using 1.0-2.0 wt.%, based on the N-vinylcarboxylic acid amide monomer, crosslinking agent; and, desirably, 0.01-10.0 wt.%, based on the total amount of the ink, N-acylamino acid (salt) (e.g. oleoyl sarcosine). Desirably, the ratio crosslinked poly-N-vinylcarboxylic acid amide to N-acylamino acid (salt) is 0.05:1 to 12:1. A ball-point pen filled with this ink can give not blurred writing even after long-distance writing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based ink used for a ball-point pen which has a ball-point pen tip for holding and holding a ball made of a cemented carbide material as a writing member and discharges ink by rotation of the ball. More specifically, a water-based ink for a ball-point pen having a lubricating effect to minimize wear of the ball seat due to contact with the ball seat of the ball-point pen while the ball rotates, and to ensure smooth rotation of the ball. About.

[0002]

2. Description of the Related Art Conventionally, a ball-point pen has a relatively thin handwriting and is more likely to be worn or crushed even when used for a long period of time as compared with a writing instrument having a fiber nib or a resin nib. Widely used because the change in handwriting width is small. The aqueous ink used for such a ballpoint pen is known to have a relatively low viscosity of 1 to several cps (25 ° C.) and a relatively high viscosity of 50 cps or more (25 ° C.). Those having 1 to several cps (25 ° C.) are mainly used for ballpoint pens having a structure using an ink occluding body such as a fiber bundle and a communicating porous body,
(5 ° C.) is mainly used for those having a structure using a hollow cylinder as an ink reservoir.

In a writing mechanism of a ballpoint pen, ink attached to the ball surface is transferred to a writing surface such as paper as the ball rotates. Ballpoint pens are basically
It is necessary to satisfy the general requirements for ballpoint pens, in which an appropriate amount of ink is transferred to the writing surface, and furthermore, there is no blurring in the handwriting, and various problems such as ink leakage from the ballpoint pen tip at the tip of the ballpoint pen do not occur. For this reason, it is required that various physical properties such as the viscosity and surface tension of the ink are appropriate, and that the handwriting has a high concentration and is excellent in water resistance and light resistance.

In particular, ballpoint pens using water-based inks
Since the friction coefficient of water, which is the main solvent, is larger than that of the oil-based solvent, relatively large frictional resistance is generated between the ball and the ball seat due to the rotation of the ball compared to the oil-based ink. In some cases, the receiving seat was worn, the ball sinked, and the height of the ball protruding from the ballpoint pen tip was reduced. In the case of a ball with a lower height, the tip of the ball-point pen tip (other than the ball) may be caught on the surface to be written, impairing a smooth writing feeling, or the ink circulation hole formed in the ball receiving seat may be replaced with a ball. In some cases, resulting in insufficient ink discharge. In any case, a problem such as faint handwriting or heavy writing feeling occurs. In order to solve this problem, a water-soluble cutting oil such as an oxyethylene-oxypropylene copolymer or a surfactant such as a polyoxyethylene alkyl ether, a polyoxyethylene hardened castor oil, or an N-acyl amino acid salt is used in the ink. Attempts have been made to increase the lubricity of the ink by adding it as a lubricant.

[0005]

As described above, water-soluble cutting oils such as oxyethylene-oxypropylene copolymers, polyoxyethylene alkyl ethers, and polyoxyethylene hardened castor oils which have been conventionally used as lubricants. For example, it is necessary to add a relatively large amount to sufficiently exert a lubricating effect. However,
If the addition amount is too large, it affects the balance of the ink composition, making it difficult for various physical properties to work properly, and causing various dangers such as blurring and blurring in handwriting and ink leakage from a metal ballpoint pen tip at the tip of a ballpoint pen. there were. If the above-mentioned lubricant is used in such a small amount that does not cause these various problems, the wear and deformation of the ball seat will not be sufficiently suppressed, and the handwriting will be blurred when writing over a long distance. Would. In addition, depending on the properties such as ionicity and solubility of various additives such as lubricants and thickeners in the ink, and the amount added, the dissolution / dispersion balance of each composition in the ink is disrupted, and the ball seating As a result, insoluble / agglomerated materials acting as an abrasive may be generated, and the handwriting may be blurred.

The N-acylamino acid salt dissociates and has a charge. When used in an ink for a ballpoint pen, a carboxyl group is electrically compatible with the metal surface of the ball seat,
The layers are arranged on the ball seating surface. The N-acylamino acid ion layer formed on the ball seat acts as a lubricant, and reduces the frictional force as compared with the metal-to-metal contact when the ball and the ball seat are in direct contact. Therefore, since the adhesive force to the ball and the ball seat is stronger than the water-soluble cutting oil and the surfactant described above,
The lubricity could be improved by adding a small amount to some extent. However, considering the effect of the balance of the ink composition, it is difficult to add an amount for obtaining a sufficient lubricating effect, and in a layer containing only an N-acylamino salt,
Depending on the writing pressure and the magnitude of the shearing force due to the rotation of the ball, this layer may be broken, and the desired lubricity may not be provided.

SUMMARY OF THE INVENTION It is an object of the present invention to satisfy the general requirements for a ballpoint pen and to secure good ink dischargeability by minimizing wear and deformation of a ball seat due to rotation of a ball. It is an object of the present invention to provide a water-based ink for a ball-point pen, which makes it possible to prevent the handwriting from being blurred even when writing at a distance.

[0008]

That is, the present invention provides water,
A coloring agent, a crosslinked poly N-vinyl carboxylic acid amide,
The gist of the present invention is a water-based ink for a ballpoint pen comprising at least an N-acylamino acid and / or a salt thereof.

As the colorant, any of the dyes and pigments conventionally used in aqueous inks can be used without limitation. Specific examples of the dye include Japanol Fast Black D Conc (CI Direct Black). 1
7), Water Black 100L (19), Water Black L-200 (19), Water Black # 7 (19), Kayaset Black W9 (1)
9), Direct Fast Black B (22), Direct Fast Black AB (32), Direct Deep Black EX (38), Direct Deep Black (38 similar products), Direct Fast Black Conch (51), Kaya Rath Sprague VGN (7
1), Kayak Direct Brilliant Yellow G (C.I.
I. Direct Yellow 4) Direct Fast Yellow 5
GL (26), Aizen Brimura Yellow GCLH (44), Direct Fast Yellow R (50), Aizen Direct Fast Red FH (CI Direct Red 1), Nippon Fast Scarlet GSX
(4), Direct Fast Scarlet 4BS (23), Eisen Direct Durin BH (31),
Direct Scarlet B (37), Kayak Direct Scarlet 3B (39), Aizen Murabin Conch 2BLH (75), Sumilight Red F3B
(80), Eisen Burimura Red 4BH (81)
Kayalas Sprarubin BL (83), Kayalas Light Red F5G (225), Kayalas Light Red F5
B (226), Kayasu Light Rose FR (22)
7) Direct Sky Blue 6B (CI Direct Blue 1), Direct Sky Blue 5B (15),
Benzo Brilliant Sky Blue 8GS (41), Sumilite Supra Blue BRR Conc (71), Diebogen Turquoise Blue S (86), Water Blue # 3 (86), Kayara Star Coy Blue GL (86), Direct dyes such as Daiwa Blue 215H (87), Kayalas Supra Blue FF2GL (106), Kayaras Supra Blue FFRL (108), Kayaras Splatter Turquoise Blue FBL (199) and Acid Blue Black 10B (C.I. I. Acid Black 1),
Nigrosine (2), Water Black R455 (2), Water Black R510 (2), Suminol Milling Black 8BX (24), Kayanol Milling Black VLG (26), Kayanol Milling Black BR Conc (2) 31), Mitsui Nylon Black GL (52), Eisen Opal Black WH Extra Conc (52), Sumilan Black WA (5)
2), Ranyl Black BG Extra Conc (10
7), Kayanol Milling Black TLB (10
9), Suminol Milling Black B (109), Kayanol Milling Black TLR (110), Eisen Opal Black New Conc (119), Water Black 187-L (154) Acid Yellow # 10 (CI) Acid Yellow 1), Kayak Acid Brilliant Flavin FF (7: 1), Kayasil Yellow GG (17), Xylene Light Yellow 2G 140%
(17), Suminol Leveling Yellow NR (1)
9), Water Yellow # 1 (23), Daiwa Torazine (25), Kayaktor Trazine (23),
Suminol Fast Yellow R (25) Diacid Light Yellow 2GP (29), Suminol Milling Yellow O (38), Suminol Milling Yellow MR (4)
2), Water Yellow # 6 (42), Kayanol Yellow NFG (49), Suminol Milling Yellow 3
G (72), Suminol Fast Yellow G (6)
1), Suminol Milling Yellow G (78), Kayanol Yellow N5G (110), Suminol Milling Yellow 4G 200% (141), Kayanol Yellow NG
(135), Kayanol Milling Yellow 5GW (1
27), Kayano Lumiling Yellow 6GW (14
2), Sumitomo Fast Scarlet A (CI Acid Red 8), Kayak Silk Scarlet (9),
Solar Rubin Extra (14), Daiwa New Koksin (18), Water Scarlet (1)
8), Daiwa Red No. 102 (18), Eisenbon Saw RH (26), Daiwa Red 2 (27), Suminol Leveling Brilliant Red S3B (35),
Kayasil rubinol 3GS (37), Aizen erythrosine (51), kayak acid rhodamine FB (52), Daiwa red No. 106 (52), Suminol leveling rubinol 3GP (57), Diacid alizarin rubi Nord F3G 200% (82), Alizarin Rubinol 5G (83), Eizen Eosin GH
(87), Water Red # 2 (87), Daiwa Red 103WB (87), Water Pink # 2 (92), Eisen Acid Phloxine PB (92),
Daiwa Red No. 104 (92), Rose Bengal (9)
4), Kayanol milling scarlet FGW (11
1), Kayanol Milling Rubin 3BW (129)
Suminol Milling Brilliant Red 3BN Conc (131), Suminol Milling Brilliant Red BS (138), Aizen Opal Pink BH (1)
86), Suminol Brilliant Red B Conch (2
49), Kayak Acid Brilliant Red 3BL (254), Kayak Acid Brilliant Red BL (265), Kayanol Milling Red GW (27)
6), Mitsui Acid Violet 6BN (CI Acid Violet 15), Mitsui Acid Violet BN (17), Water Violet # 1 (4)
9), Water Violet # 5 (49), Daiwa Purple No. 1 (49), Ink Violet L10 (4)
9), Sumitomo Patent Pure Blue VX (CI Acid Blue 1), Water Blue # 106 (1), Patent Blue AF (7), Water Blue # 9 (9), Daiwa Blue 1 ( 9), Ink Blue L20 (9), Spranol Blue B (15), Water Blue # 116 (15), Orient Soluble Blue OBC (22), Orient Soluble-
OBX (22), Sumino-le leveling blue 4GL
(23), Mitsui Nylon Fast Blue G (2)
5), Kayasil Blue AGG (40), Kayasil Blue BR (41), Mitsui Alizarin Safirol SE
(43), Suminol Leveling Sky Blue R Extra Conch (62), Mitsui Nylon Fast Sky Blue R (78), Sumitomobrilliant Indocyanine 6Bh / e (83), Sandran cyanine N-
6B350% (90), Water Blue # 115
(90), Water Blue # 105 (90), Orient Soluble Blue OBB (93), Spranol Cyanine 7BF (100), Sumitomobrilliant Blue 5G (103), Acid Blue (10)
3), Asilane brilliant blue FFR (10
4), Kayanol Milling Ultra Sky SE (11
2), Kayanol milling cyanine 5R (113);
Aizen Opal Cyanine 2GLH (158), Daiwa Guinea Green B (CI Acid Green 3) Acid Brilliant Milling Green (9), Daiwa Green # 70 (16), Kayanol Cyanine Green G (25) ), Suminol Milling Green G (2
7), acid dyes such as water orange # 17 (CI acid orange 56), water yellow # 2
(CI Food Ero-3), Food Yellow No. 5 (C.I.
I. Food yellow 3) Food red 3 (CI food red 14), food blue 2 (CI acid blue 74), food green 2 (CI acid green 5), etc. Food dye, malachite green (CI.4
2000), Victoria Blue FB (CI. 4404)
5), methyl violet FN (C.I.
5), basic dyes such as rhodamine F4G (CI. 45160) and rhodamine 6GCP (CI. 45160).

As the pigment, conventionally known pigments can be used.
As specific examples, SpecialBlack 6 and S
170, S610, 5, 5, 4, 4A, 550,
35, 250, 100, Printex 150
T, U, V, 140U, 140V, 95, 90, 85, 80, 75, 55, 45, 45, P, XE2, L6, L, 300 30, 30, 35, 25, 200, A, G (all manufactured by Degussa Japan KK), # 2400B, # 235
0, # 2300, # 2200B, # 1000, # 95
0, # 900, # 850, # MCF88, MA600,
MA100, MA7, MA11, # 50, # 52, # 4
5, # 44, # 40, # 33, # 32, # 30, CF
9, # 20B, # 4000B (Mitsubishi Chemical Industries, Ltd.), MONARCH 1300, 1100,
1000, 900, 880, 800, 70
0, MOGULL, REGAL 400R, 660
R, 500R, 330R, 300R, 99R,
ELFTEX 8, 12 and BLACK PEARLS
2000 (above, USA, Cabot Co. Ltd.
Manufactured), Raven7000, 5750, 5250,
5000, 3500, 2000, 1500, 1255, 1250, 1200, 1170, 1
060, 1040, 1035, 1020, 10
00, 890H, 890, 850, 790, 780, 760, 500, 450, 430, 420, 410, 22, 22, 16, 14, and 825
Oil Beads, H20, C, Conduc
carbon blacks such as tex 975, 900, and SC (all manufactured by Colombian Carbon Japan Co., Ltd.);
KA-10, 10P, 15, 15, 20, 30, 3
5, 60, 80, 90, KR-310, 38
0, 460, 480 (Titanium Industry Co., Ltd.
Titanium oxide such as P25 (manufactured by Nippon Aerosil Co., Ltd.), BS-605, and 607 (manufactured by Toyo Aluminum Co., Ltd.), and bronze powders P-555 and P-77.
7 (above, manufactured by Nakajima Metal Foil Industry Co., Ltd.), bronze powder 3L5, 3L7 (above, manufactured by Fukuda Metal Foil Industry Co., Ltd.)
Metal powder pigments, such as black iron oxide, yellow iron oxide, red iron oxide, ultramarine, navy blue, cobalt blue, chrome green, chromium oxide and other inorganic pigments, Hansa A-10G,
5G, 3G, 4, GR, A, Benzidine Yellow, Permanent Yellow NCG, Tartrazine Lake,
Quinoline yellow, Sudanese 1, permanent orange,
Indus Ren Brilliant Orange GN, Permanent Brown FG, Para Brown, Permanent Red 4
R, Fire Red, Brilliant Carmine BS, Pyrazolone Red, Lake Red C, Quinacridone Red, Brilliant Carmine 6B, Bordeaux 5B, Thioindigo Red, Fast Violet B, Dioxane Violet, Alkaline Blue Lake, Phthalocyanine Blue, Indigo, Acid Green Lake, Organic pigments such as phthalocyanine green are exemplified. Also,
In addition, inorganic fluorescent pigments such as zinc sulfide, zinc silicate, cadmium zinc sulfate, calcium sulfide, strontium sulfide, calcium tungstate, and other known organic fluorescent pigments can be used. The above-mentioned colorants can be used alone or in combination with others.The amount of use varies depending on the color tone, etc., but when the amount is small, the color development of the ink is poor, and when the amount is large, the colorant is insufficiently dissolved / dispersed. Since a problem occurs, the amount of the aqueous ink is 0.1 to 4%.
0% by weight is preferred.

Here, when a pigment is used as a colorant,
It is preferable to use a dispersant in combination, and as the dispersant, a water-soluble or water-soluble resin conventionally used generally as a pigment dispersant, an anionic or nonionic surfactant, or the like can be used. As an example, as a polymer dispersant, gum arabic, natural gums such as tragacanth gum, glucosides such as saponin, methylcellulose, carboxycellulose, cellulose derivatives such as hydroxymethylcellulose, lignin sulfonate,
Natural polymers such as shellac, polyacrylates, salts of styrene-acrylic acid copolymers, salts of vinylnaphthalene-maleic acid copolymers, sodium salts of β-naphthalenesulfonic acid formalin condensates, phosphates, etc. And nonionic polymers such as polyvinyl alcohol and polyethylene glycol. Also,
As surfactants, alkyl sulfates, polyoxyethylene alkyl ether sulfates, N-acylmethyl taurine salts, polyoxyethylene alkyl ether acetates, alkyl sulfocarboxylates, α-olefin sulfonates, alkyl phosphates, Examples include anionic surfactants such as polyoxyethylene alkyl ether phosphate, and nonionic surfactants such as polyoxyethylene alkyl ethers, sorbitan alkyl esters, and polyoxyethylene sorbitan alkyl esters. One or two or more of these can be selected and used in combination. When the amount is small, the dispersing effect to be added is weak, and when the amount is large, the dissolution balance of each composition in the ink is disturbed and various problems occur. % By weight is preferred.

Further, in the case of a pigment ink, it is advantageous in the production of a pigment ink to use an aqueous ink base in which a pigment is dispersed in an aqueous medium. Specifically, Fuji S
PBlack 8031, 8119, 8167, 8276, 8381, 8406, Fuji SP
Red 5096, 5111, 5193, 522
0, Fuji SP Bordeaux 5500, F
uji SP Blue 6062, 6133, 6
134, Fuji SP Green 7051, Fu
ji SP Yellow 4060, Fuji SP
Violet 9011, Fuji SP Pink
9524, 9527, FujiSP Orange
534, FUji SP Brown 3074 (all manufactured by Fuji Dye Co., Ltd.), Emacol Black
CN, Emacol Blue FBB, FB, K
R, Emacol Green LXB, Emacol
Violet BL, Emacol Brown 3
101, EmacolCarmmine FB, Ema
col Red BS, Emacol Orange
R, Emacol Yellow FD, IRN, 3601, FGN, GN, GG, F5G, F
7G, 10GN, 10G, Sandy Suppe
r Black K, C, Sandye Super
Gray B, Sandy Super Brow
n SB, same FRL, same RR, Sandy Suppe
r Green L5G, GXB, Sandy S
upper Navy Blue HRL, GLL, HB, FBL-H, FBL-160, FBB, S
andy Super Violet BLH / C,
BL, Sandy Super Bordeaux
FR, Sandye Super Pink FB
L, F5B, Sandy SuperRubine
FR, Sandye super Carmine
FB, Sandy Super Red FFG,
Same RR, Same BS, SandySuper Orange
e FL, R, BO, Sandye Gold Y
yellow 5GR, same R, same 3R, Sandye Y
wllow GG, F3R, IRC, FGN, GN, GRS, GSR-130, GSN-13
0, the same GSN, the same 10GN (above, Sanyo Dyeing Co., Ltd.)
Manufactured), Rio FastBlack Fx 8012,
8313, 8169, Rio FastRed F
x 8209, 8172, Rio Fast Red
S Fx8315, 8316, Rio Fast
Blue Fx 8170, RioFast Blue
FX 8170, Rio Fast Blue S
FX 8312, Rio Fast Green S
Fx 8314 (all manufactured by Toyo Ink Co., Ltd.), NKW
-2101, 2102, 2103, 2104, 2105, 2106, 2107, 2108, 2
117, 2127, 2137, 2167, 21
01P, 2102P, 2103P, 2104P,
2105P, 2106P, 2107P, 210
8P, 2117P, 2127P, 2137P, 2167P, NKW-3002, 3003, 300
4, 3005, 3007, 3077, 300
8, 3402, 3404, 3405, 340
7, 3408, 3377, 3602, 360
3, 3604, 3605, 3607, 367
7, 3608, 3702, 3703, 370
4, 3705, 3777, 3708, 601
3, 6038, 6559 (The above are from Nippon Fluorescence Co., Ltd.)
Co., Ltd.), Cosmo Color S 1000F Series (manufactured by Toyo Soda Co., Ltd.), Victoria Yellow G-11, G-2
0, Victoria Orange G-16, G-21, Victoria Red G-19, G-22, Victoria Pink G-17, G-23, Victoria Green G-
18, G-24, Victoria Blue G-15, G
-25 (all manufactured by Mikuni Pigment Co., Ltd.), and these can be used alone or in combination of two or more.

As a solvent or a dispersion medium, various water-soluble organic solvents can be used in addition to water, which is an essential requirement. These solvents have various qualities as an aqueous ink, for example, prevention of ink drying at a pen tip, low temperature. It is used for the purpose of preventing freezing of the ink at the time and the dispersion medium of the pigment. Specifically, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, 1,3-butylene glycol, thiodiethylene glycol, and glycerin; ethylene glycol monomethyl ether; diethylene glycol monomethyl ether; Pyrrolidone can be used,
These can be used alone or in combination of two or more. In addition, when the amount is small, insoluble / aggregate is generated due to insufficient dissolution or dispersion of each composition in the ink, and when the amount is large, the concentration of each composition in the ink becomes small and the effect is small. And various problems occur,
It is preferably from 5 to 40% by weight based on the total amount of the ink.

The cross-linked poly N-vinyl carboxylic acid amide is mainly used as an auxiliary agent for N-acyl amino acids and / or salts thereof which suppresses wear and deformation of the ball seat. As an example of the cross-linked poly N-vinyl carboxylic acid amide, the type of the carboxylic acid amide portion is acetamide or formamide, and the amount of the cross-linking agent added to the N-vinyl carboxylic acid amide monomer at the time of production is 1.5.
0%, 0.45% and the like.
X-205 (the carboxylic acid amide moiety is acetamide, and the amount of the crosslinking agent added is 1.50%, manufactured by Showa Denko KK). It also acts as a water-soluble thickener in the ink, increasing the viscosity of the entire ink and stabilizing the dispersion by retaining the colorant, or preventing ink leakage by lowering the fluidity of the ink. It is also possible to make it difficult for a defect to occur. Specifically, since each effect is enhanced by swelling in a solvent or a dispersion medium and having elasticity, the amount of a cross-linking agent used in the production of cross-linked poly N-vinyl carboxylic acid amide is reduced. It is preferably 1.0 to 2.0% based on the monomer. Furthermore, since the elasticity to be retained is increased by swelling in a solvent or a dispersion medium and each effect is enhanced, it is preferable that the cross-linked poly N-vinyl carboxylic acid amide is in the form of fine particles.
The amount of the cross-linked poly N-vinyl carboxylic acid amide used cannot be unconditionally determined in consideration of the interaction with other inks. However, if the amount is too small, the effect of suppressing wear and deformation of the ball seat decreases. If the amount is too large, the viscosity of the ink becomes excessively large and the rotation of the ball makes it difficult to discharge the ink. Therefore, the amount is preferably 0.1 to 15.0% by weight based on the total amount of the ink.

One or more N-acyl amino acids and / or salts thereof are selected and used to suppress wear and deformation of the ball seat. Specific examples of N-acyl amino acids include lauroyl sarcosine, myristoyl sarcosine, palmitoyl sarcosine, oleoyl sarcosine, lauroyl methylalanine and the like. Specific examples of N-acyl amino acid salts include sodium, potassium, lithium, and amine salts of N-acyl amino acids. N-
The acyl amino acid salt may be used as a salt in the ink in advance, or may be used as a salt in the ink by using an N-acyl amino acid and an alkali together at the time of formulating the ink. Specific examples of the alkali in that case Examples thereof include sodium hydroxide, lithium hydroxide, potassium hydroxide, monoethanolamine, diethanolamine, triethanolamine, 2-amino-2-methyl-1,3-propanediol, and the like. The total amount of the N-acyl amino acid and / or its salt cannot be determined unconditionally in consideration of the interaction with other ink compositions, but when the amount is small, the effect of suppressing wear and deformation of the ball seat is small. Become
If the amount is large, the dissolution or dispersion balance of each composition in the ink is destroyed and various problems occur, so that the amount is preferably 0.01 to 10.0% by weight based on the total amount of the ink. Further, considering the interaction with the cross-linked N-polyvinyl carboxylic acid amide, the added amount of the cross-linked N-polyvinyl carboxylic acid amide: the added amount of the N-acyl amino acid and / or the salt thereof = 0.05: 1 to 12 : 1 is preferred.

In addition to the crosslinked poly N-vinyl carboxylic acid amide, a water-soluble polymer can be used in combination for adjusting the viscosity of the ink or for stabilizing the dispersion of the coloring material. Specifically, polyvinyl alcohol, polyvinyl methyl ether, sodium polyacrylate, carboxyvinyl polymer, polyethylene oxide, copolymer of vinyl acetate and polyvinylpyrrolidone, alkali metal salt of acrylic resin, copolymer of acrylic acid and alkyl methacrylate , Natural gum arabic, tragacanth gum, xanthan gum, guar gum, locust bean gum, alginic acid, carrageenan, gelatin, casein, dextran, semi-synthetic methylcellulose, ethylcellulose,
Examples include hydroxyethyl cellulose, carboxymethyl cellulose, sodium starch glycolate, sodium alginate, propylene glycol alginate, and derivatives thereof.

Further, in order to suppress the outflow inhibition of the ink in the ink passage of the writing instrument due to the generation of mold, sodium dehydroacetate, 1,2-benzothiazalin-3-one,
An appropriate amount of a preservative and fungicide such as sodium benzoate can also be added.

Further, in the case of a writing instrument using a metal in a portion that comes into contact with the ink, a corrosion inhibitor such as benzotriazole or ethylenediaminetetraacetic acid for preventing metal corrosion, or a fatty acid such as oleic acid as a solubilizing agent is used. Can also be added.

In producing the ink of the present invention, various conventionally known methods can be employed. For example, when a dye is used as a coloring material, the mixture is stirred and mixed by a stirrer such as a turbo mixer, and when a pigment is used as a coloring material, a ball mill, a sand grinder,
It can be easily obtained by mixing and grinding with a disperser such as a speed line mill or a roll mill.

[0020]

[Action] Cross-linked poly N-vinyl carboxylic acid amide and N-
The reason why the use of an acylamino acid and / or a salt thereof in combination for the ink is effective in suppressing the abrasion of the ball seat is presumed as follows. In a solvent or a dispersion medium, the N-acylamino acid and / or a salt thereof dissociates and has a charge, and the cross-linked polyN
The amide group of the vinyl carboxylic acid amide and the acyl group of the N-acyl amino acid and / or a salt thereof are immobilized with affinity by hydrogen bonding or the like. That is, the crosslinked poly N-vinyl carboxylic acid amide links each molecule of N-acyl amino acid and / or its salt. On the other hand, the carboxyl group of the N-acylamino acid and / or its salt is electrically compatible with the metal surface of the ball seat, and the N-acylamino acid and the N-acylamino acid bonded to the swollen cross-linked poly-N-vinylcarboxylic acid amide. And / or its salts are arranged on the ball seating surface to form a layer. When the N-acylamino acid and / or a salt thereof is bonded to the crosslinked polyN-vinylcarboxylic acid amide, the swollen crosslinked polyN-vinylcarboxylic acid amide causes the N-acylamino acid and / or a salt thereof to form a layer. The elasticity is imparted, making it difficult to break. Therefore, even if the writing pressure at the time of writing or the shearing force due to the rotation of the ball is large, the lubricating effect of the N-acylamino acid and / or its salt is maintained, and the friction can be reduced. Then, the elasticity of the swollen cross-linked poly N-vinyl carboxylic acid amide absorbs the force of pressing the ball in the ball receiving direction, so that the layer of the N-acyl amino acid and / or its salt is not easily broken. The lubrication effect is maintained.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. The viscosity of each ink in Examples and Comparative Examples was 50 cps.
Less than 50 cps to 600 cp measured with a standard cone rotor at 10 rpm, ELD viscometer manufactured by Tokimec Co., Ltd.
Less than s is measured with a standard cone rotor at 1 rpm, ELD viscometer manufactured by Tokimec Co., Ltd.
For less than cps, measured with a Tokimec ELD viscometer ST rotor at 10 rpm. For more than 2000 cps, Tokimec ELD viscometer ST rotor 2.5
It was measured at rpm. The temperature during the measurement was 25 ° C.
In each of the examples, “parts” means “parts by weight”.

Example 1 MICRO JET BLACK M-800 (black aqueous pigment base, manufactured by Orient Chemical Industry Co., Ltd.) 25.00 parts GX-205 (cross-linked poly N-vinylacetamide, manufactured by Showa Denko KK) 1.30 parts Oleoyl sarcosine 0.50 part Proxel GXL (preservative, manufactured by ICI Japan) 0.15 parts Ethylene glycol 22.00 parts Water 50.85 parts 25% 2-aminomethyl 1,3-propane Diol 0.20 part Among the above components, GX-205, MICRO JET B
Mix and stir for 2 hours with a stirrer except for LACK M-800, and then MICRO JET BLACK M-
800, and mixed and stirred for 1 hour.
205 was added thereto, and the mixture was stirred again for 4 hours.
A black aqueous ink of cps was obtained.

Example 2 Sundai Super Violet BL (purple aqueous pigment base, manufactured by Sanyo Pigment Co., Ltd.) 40.00 parts GX-205 2.76 parts Lauroyl sarcosine 0.24 parts Propylene glycol 3.00 parts Water 53 .80 parts Glycine betaine (solubiliser) 0.20 part Among the above components, components other than GX-205 and lauroyl sarcosine were mixed and stirred for 1 hour with a stirrer, and then lauroyl sarcosine was added and mixed for 1 hour. After stirring, GX-205 was further added and stirred again for 5 hours.
A purple water-based ink having a viscosity of 10020 cps was obtained.

Example 3 Water Pink # 2 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 1.00 part GX-205 0.40 part Myristoyl sarcosine sodium salt 4.00 parts Water 84.60 parts Ethylene glycol 10.00 Part In the above components, components other than GX-205 were mixed and stirred for 3 hours, and then GX-205 was added and stirred with a stirrer for 2 hours to obtain a pink aqueous ink having a viscosity of 180 cps.

Example 4 Water Blue # 9 (Dye, manufactured by Orient Chemical Industry Co., Ltd.) 7.00 parts GX-205 2.00 parts Palmitoyl sarcosine sodium salt 0.34 parts Lauroyl sarcosine 0.02 parts Diethylene glycol 12.00 Part Sodium dehydroacetate (preservative) 0.20 part Water 78.44 parts Among the above components, after mixing and stirring components other than GX-205 for 1 hour, add GX-205 and stir again for 5 hours, A blue water-based ink of 3720 cps was obtained.

Example 5 NKW-6013 (red aqueous pigment base, manufactured by Nippon Fluorescent Chemical Co., Ltd.) 28.00 parts GX-205 1.20 parts Demol N (β-naphthalenesulfonic acid formalin condensate Na salt, Kao ( 0.20 part Glycerin 6.50 parts Oleoyl sarcosine sodium salt 1.00 part Water 62.85 parts Proxel GXL 0.25 part In the above components, components other than GX-205 and oleoyl sarcosine sodium salt Was mixed and stirred with a stirrer for 1 hour, oleoyl sarcosine sodium salt was added and mixed and stirred for 1 hour, and then GX-205 was added and stirred again for 3 hours to obtain a red aqueous ink having a viscosity of 395 cps.

Example 6 MA100 (carbon black, manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) 10.00 parts GX-205 0.15 parts lauroylmethylalanine sodium salt 2.00 parts glycerin 5.00 parts sodium dehydroacetate 0.25 Part 82.60 parts of water After stirring and mixing components other than GX-205 in the above components for 2 hours, adding GX-205 and stirring again for 3 hours,
A black aqueous ink having a viscosity of 70 cps was obtained.

Example 7 JR301 (titanium oxide, manufactured by Teica Corp.) 30.00 parts GX-205 4.00 parts Oleoyl sarcosine 0.80 part Lauroyl sarcosine sodium salt 0.53 part Propylene glycol 20.00 parts Penta Erythritol 5.00 parts Water 38.67 parts Triethanolamine 1.00 part Of the above components, components other than GX-205 were stirred and mixed with a stirrer for 3 hours, and then GX-205 was added and stirred again for 5 hours. And a white water-based ink having a viscosity of 28000 cps.

Comparative Example 1 A black aqueous ink having a viscosity of 40 cps was obtained in the same manner as in Example 1 except that oleoyl sarcosine was added in the same amount except for GX-205 of Example 1.

Comparative Example 2 A purple aqueous ink having a viscosity of 13100 cps was obtained in the same manner as in Example 2 except that decaglyceryl monolaurate was added in the same amount except for lauroyl sarcosine in Example 2.

Comparative Example 3 A pink aqueous ink having a viscosity of 15 cps was prepared in the same manner as in Example 3 except that the ammonium salt of the styrene-acrylic acid copolymer was added in the same amount except for GX-205 of Example 3. Obtained.

Comparative Example 4 Except for the palmitoyl sarcosine sodium salt and lauroyl sarcosine of Example 4, except that GX-205 was added in the same amount, the viscosity was 9850 cps.
Was obtained.

Comparative Example 5 A red aqueous ink having a viscosity of 8610 cps was obtained in the same manner as in Example 5, except that sodium carboxymethylcellulose was added in the same amount except for GX-205 of Example 5.

As described above, the aqueous inks obtained in Examples 1 to 7 and Comparative Examples 1 to 5 were used as transparent transparent polypropylene hollow cylinders having one end connected with a stainless steel ballpoint pen tip holding a carbide ball. 0.8 g of the ink was filled in the ink storage tube, and the writable distance, the ball sinking amount, and the ink leakage were tested. The results are shown in Tables 1 and 2.

Writing distance: Using a rotating continuous spiral writing tester (writing tester MODEL TS-4C-20 manufactured by Seiki Kogyo Kenkyusho) at a writing speed of 7 cm / sec and a load of 100.
g, continuous writing was performed at a writing angle of 70 °, and the writing distance was measured until a continuous handwriting was not obtained (handwriting was blurred). (However, Examples 1 to 7 and Comparative Examples 1 and 3
Used all of the filled ink. In Comparative Examples 2, 4, and 5, about 10 to 20% of the filled ink remained, but the handwriting was markedly blurred.)

Ball sinking amount: In the above-described writing test, the difference between the ball protrusion length before writing and the ball protrusion length after 400 m continuous writing was defined as the ball sinking amount. In addition, the ball protrusion length is measured by placing the ballpoint pen sideways,
A stainless steel plate is pressed against the ball tip of the ball-point pen tip with a load of 200 g so that the ball comes into contact with the ball receiving seat, and a tool microscope (Model STM-DH manufactured by Olympus Optical Co., Ltd.) is used. The length from the opening end of the ball pen tip to the tip of the ball was measured.

Ink leakage: The ink-filled ball-point pen was left down at room temperature for 30 minutes without capping so that the tip did not come into contact with the surroundings, and the presence or absence of ink leakage from the tip was visually determined. .

[0038]

[Table 1] * 1: Added amount of cross-linked poly N-vinyl carboxylic acid amide: added amount of N-acylamino acid and / or salt thereof

[0039]

[Table 2]

[0040]

As described above in detail, the water-based ink according to the present invention satisfies the general requirements for a ballpoint pen, can reduce the wear and deformation of the ball seat due to the rotation of the ball, and can reduce the ball sinking. The initial purpose of preventing the occurrence of the problem can be sufficiently achieved. Therefore, it is possible to realize that the handwriting is not blurred even with a long writing distance.

Claims (1)

[Claims] An aqueous ink for a ballpoint pen comprising at least water, a colorant, a crosslinked poly N-vinyl carboxylic acid amide, and an N-acyl amino acid and / or a salt thereof.