JPH1077435A - Water-base ink composition for writing utensil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-base dispersion which is used as an ink base and is stable during storage without causing precipitation and an ink compsn. excellent in resistances to water and light by dissolving a water-soluble dye in a specific emulsion polymn. liq. and thermally treating the resultant soln. SOLUTION: An emulsion polymn. liq. is obtd. by subjecting a mixture of at least one hydrophobic monomer (e.g. an acrylic ester such as methyl acrylate, a methacrylic ester, a vinyl ester, an olefin, or styrene), 50wt.% or lower hydrophilic monomer having a hydrophilic grip (e.g. an amino or carboxyl group), and a cross-linker to emulsion polymn. in the presence of a polymn. initiator and 0.1-20wt.% (based on the vinyl monomers) polymerizable surfactant comprising a compd. having a surface (interface)-active vinyl group. A water-soluble dye in an amt. of 0.2-50wt.% of the solids in the polymn. liq. is dissolved in it and the resultant soln. is heated at 50-150 deg.C for 1-12hr under pressure to give a water-base dispersion of colored resin particles. The dispersion is diluted with water and a water-soluble org. solvent to give an ink compsn. for writing utensils.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aqueous ink composition for a writing instrument. More specifically, the present invention relates to an aqueous dispersion of colored resin fine particles for an ink, which is a base of the ink, and an aqueous ink composition which does not bleed during writing and is useful for writing instruments such as a felt-tip pen and a ball-point pen.

[0002]

2. Description of the Related Art Dyes and pigments are known as coloring components of water-based inks used for writing instruments such as water-based sign pens and water-based ball-point pens. Inks using dyes have the drawback that letters and drawn lines are blurred or disappeared by sweat or water because the dyes are soluble in water, and the written letters and drawn lines are unclear, resulting in poor so-called water resistance. Further, since the dye itself has poor light fastness, there is a problem that characters and drawn lines are deteriorated over a long period of time. On the other hand, an ink using a pigment has no problem with respect to water resistance and light resistance, but causes a problem such as clogging of a pen tip and poor writing due to aggregation or settling of the pigment over a long period of time. Further, since the ink for writing implements is required to have a finely dispersed pigment, it is difficult to increase the number of colors of the ink by dispersing various colored pigments.

[0003]

The problem to be solved by the present invention is to solve the above-mentioned drawbacks and problems, and it is a coloring for ink which is a base of storage-stable ink which does not cause precipitation. Aqueous ink composition for writing implements that provides an aqueous dispersion of fine resin particles, and is clear, does not bleed or disappear by water or sweat, and does not deteriorate for a long time. It is to provide things.

[0004]

The present inventors have made various studies to solve the above-mentioned problems, and as a result, have found that a polymerization solution obtained by emulsion-polymerizing a vinyl monomer in the presence of a polymerizable surfactant is used as a water-soluble dye. The present inventors have found that an excellent aqueous ink composition for a writing instrument can be obtained by using an aqueous dispersion of colored resin fine particles obtained by heat treatment together with an ink base as an ink base, and completed the present invention.

The aqueous dispersion of colored resin fine particles for ink of the present invention is obtained by heat-treating a solution obtained by dissolving a water-soluble dye in an emulsion polymerization solution obtained by emulsion polymerization of a vinyl monomer in the presence of a polymerizable surfactant. Is the feature. Preferably, the heat treatment is performed under pressure.

[0006] The aqueous ink composition for a writing instrument of the present invention is obtained by heat-treating a liquid obtained by dissolving a water-soluble dye in an emulsion polymerization solution obtained by emulsion polymerization of a vinyl monomer in the presence of a polymerizable surfactant. It comprises an aqueous dispersion of colored resin fine particles for ink, a water-soluble organic solvent and water. Preferably, it contains 3 to 30% by weight (resin solid content) of the colored resin fine particle aqueous dispersion for ink, 5 to 80% by weight of the water-soluble organic solvent, and 30 to 90% by weight of water.

[0007] The emulsion polymerization solution relating to the aqueous dispersion of colored resin fine particles for ink of the present invention is obtained by emulsion polymerization of a vinyl monomer in the presence of a polymerizable surfactant. The polymerizable surfactant is not particularly limited as long as it is a compound having a vinyl group having a surface (interfacial) activity.
There is no limitation on the ionicity of anions, cations, and nonions. For example, "Adekaria Soap NE-10", "NE-20", "NE-30", manufactured by Asahi Denka Kogyo Co., Ltd.
“NE-40” and “SE-10N”, “Latemul S-180” and “S-120A” manufactured by Kao Corporation, and “Eleminol JS-2” manufactured by Sanyo Chemical Industries, Ltd. , And one or more of them are used in combination. The amount of the polymerizable surfactant used is preferably 0.1 to 20% by weight based on the vinyl monomer.

[0008] Vinyl monomers used for emulsion polymerization are:
There is no particular limitation, for example, acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, n-methacrylate.
Propyl, methacrylates such as n-butyl methacrylate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl esters such as vinyl salicylate, butadiene, isoprene, olefins such as propylene, styrene, One or more types are selected from hydrophobic monomers such as styrenes such as methylstyrene. In addition, a hydrophilic monomer having a hydrophilic functional group such as an amino group, a carboxyl group, a sulfone group, an amide group, or a hydroxyl group is preferably added within a range that does not impair emulsion polymerization, preferably within 50% by weight (based on the total amount of the vinyl monomer). )). Also, as a crosslinking agent,
A monomer having a reactive cross-linking group such as an epoxy group, a hydroxymethylamide group, an isocyanate group, or a polyfunctional monomer having two or more vinyl groups may be blended.

The emulsion polymerization solution is prepared by using the above-mentioned vinyl monomer and the polymerizable surfactant as a polymerization initiator such as ammonium persulfate, potassium persulfate, and hydrogen peroxide, or a reducing agent if necessary. An initiator is used as a starting material, and is synthesized by a usual emulsion polymerization method.

The water-soluble dye used in the aqueous dispersion of colored resin fine particles for ink of the present invention is, for example, “RHODAMINE 6GCP” (manufactured by Sumitomo Chemical Co., Ltd.)
BASIC RED 1) "and" AIZEN CATHILON PINK manufactured by Hodogaya Chemical Industry Co., Ltd. "
FGH "(CI BASIC RED 13)"
“AIZEN VICTO manufactured by Hodogaya Chemical Industry Co., Ltd.
RIA PURE BLUEBOH ”(CI BASI
C BLUE 7) "and" AIZEN ERYTHROSIN "manufactured by Hodogaya Chemical Industry Co., Ltd.
E "(CI ACIDRED 51)", "AIZEN TARTTRAZINE" manufactured by Hodogaya Chemical Industry Co., Ltd.
CONC "(CI ACID YELLOW 23)"
Acid dyes such as “DIR made by Hodogaya Chemical Industry Co., Ltd.
ECT SKY BLUE 5B "(CI DIREC
T BLUE 15) "," DIRECT FAST YELLOW GC "(C, manufactured by Hodogaya Chemical Industry Co., Ltd.)
Direct dyes such as “I DIRECT YELLOW 44)” and “DIACELITON” manufactured by Mitsubishi Chemical Corporation.
FAST RUBINE 3B "(CI DISPER
SERED 5) "," SUM manufactured by Sumitomo Chemical Co., Ltd. "
IKARON TURQUAOISE BLUES-G
L "(CI DISPERSE BLUE 60)" and the like. The amount of the dye used is usually 0.2 to the solid content (polymer fine particles) of the emulsion polymerization solution.
５０50% by weight.

The aqueous dispersion of colored resin fine particles for an ink of the present invention is characterized in that it is not a mere mixture of the above-mentioned emulsion polymerization solution and a water-soluble dye, but is subjected to a heat treatment. That is, a solution obtained by dissolving a water-soluble dye in an emulsion polymerization solution obtained by emulsion polymerization of a vinyl monomer in the presence of a polymerizable surfactant is subjected to a heat treatment to give polymer fine particles in the emulsion polymerization solution. The dye dissolved in the aqueous medium penetrates, and becomes a bright color. The conditions of the heat treatment are 50 to 150 ° C. and 1 to 12 hours. As a preferred method, the reaction is carried out under atmospheric pressure or under pressure with stirring. That is, by the above-mentioned heat treatment, an aqueous dispersion of colored resin fine particles serving as a base of an ink having good storage stability and no precipitate is obtained. The heat-treated liquid obtained as described above usually has a resin solid content of 20 to 50.
It is a concentrated solution by weight.

The aqueous ink composition for a writing instrument of the present invention is prepared by diluting an aqueous dispersion of colored resin fine particles for an ink according to the present invention, which is obtained as a concentrated liquid having a resin solid content of 20 to 50% by weight, with water and a water-soluble organic solvent. And resin solid content (polymer fine particles)
It is obtained by adjusting the amount to 3 to 30% by weight in the ink composition.

The water-soluble organic solvent used in the ink composition of the present invention includes ethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, 1,2-propanediol, 1,3-propanediol, 2-butanediol, 2,3-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 2,5-hexanediol, 3-methyl 1,3
-Butanediol, 2-methylpentane-2,4-diol, 3-methylpentane-1,3,5 triol, 1,
Alkylene glycols such as 2,3-hexanetriol and glycerin; polyalkylene glycols such as polyethylene glycol and polypropylene glycol;
Glycerols such as glycerol, diglycerol and triglycerol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-
Lower alkyl ethers of glycol such as n-butyl ether, thiodiethanol, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidaridinone and the like can be mentioned. Its content is 5 to 8 with respect to the total amount of the ink composition.
0% by weight is preferable, and more preferably 10 to 60% by weight.

In addition, for example, methyl alcohol,
Ethyl alcohol, isopropyl alcohol, n-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, hexyl alcohol, octyl alcohol,
Alcohols such as nonyl alcohol, decyl alcohol and benzyl alcohol; amides such as dimethylformamide and diethylacetamide; ketones such as acetone; N-methylpyrrolidone; and 1,3-dimethyl-2-
A water-soluble solvent such as imidazolidinone can be mixed.

If necessary, a preservative, a pH adjuster,
Activators, lubricants, defoamers, rust inhibitors and the like can be appropriately selected and used. For example, as a pH adjuster, ammonia, urea, monoethanolamine, diethanolamine, triethanolamine, sodium tripolynate, sodium carbonate or the like, an alkali metal salt of carbonic acid or phosphoric acid, an alkali metal hydroxide such as sodium hydroxide, etc. can give. Phenol, sodium omazine, sodium pentachlorophenol, 1,2-benzisothiazolin-3-one, as a preservative or a fungicide,
2,3,5,6-tetrachloro-4 (methylphonyl)
Examples include pyridine, benzoic acid, sorbic acid, alkali metal salts of dehydroacetic acid, and benzimidazole compounds. As a lubricant, a polyalkylene glycol derivative such as polyoxyethylene lauryl ether, a fatty acid alkali salt, a nonionic surfactant, a fluorine surfactant such as a perfluoroalkyl phosphate, a polyethylene glycol adduct of sea dimethylpolysiloxane, etc. And polyether-modified silicone.

In the ink composition of the present invention, the aqueous dispersion of the colored resin fine particles for an ink according to the present invention to be used is usually used.
Since the colored resin fine particles have a particle diameter of 1 μm without aggregation or sedimentation, they do not clog when passing through a fine nib such as a felt pen.

The aqueous dispersion of the colored resin fine particles for ink according to the present invention is obtained from an emulsion polymerization solution obtained by emulsion polymerization in the presence of a polymerizable surfactant. In comparison, the surface tension is high (usually 40 dyn / cm or more) because there is almost no surface active substance in the aqueous medium. for that reason,
When used as a water-based ink for writing instruments,
It is clear, does not bleed or disappear due to water or sweat, and has a water-resistant drawing film.

[0018]

The present invention will be described in more detail with reference to specific examples. In addition, the performance test in each example followed the following method. (Bleeding) The degree of bleeding of characters written on the writing paper was visually determined. ：: Does not bleed. Δ: Slight bleeding. X: Bleed. (Water resistance) The characters written on the writing paper were immersed in water for one hour, and the degree of bleeding was visually determined. ：: Does not bleed. Δ: Slight bleeding. X: Bleed. (Light fastness) The letters written on the writing paper were irradiated to the fade meter 1 and the time during which fading was observed was measured. (Storage stability) The ink composition was filled in an aqueous felt-tip pen container, placed in a 50 ° C constant temperature bath, and the number of days until writing became impossible was measured.

(Particle Size) The particle size of the colored resin fine particles in the ink composition was measured using a laser scattering type particle size distribution analyzer (Coulter Counter, Model N4SD, manufactured by Nikkiso Co., Ltd.). (Viscosity) The viscosity of the ink composition was measured using a cone plate type rotational viscometer [Tokyo Keiki Co., Ltd., ELD type]. The measurement temperature was 25 ° C. (Surface tension) The surface tension of the ink composition was measured by a hanging plate method. The measurement temperature was 25 ° C.

Example 1 A 2 liter flask was equipped with a stirrer, reflux condenser, thermometer, nitrogen gas inlet tube, 500 ml separatory funnel for charging monomer, set in a hot water tank, and charged with 250 g of distilled water. Then, the internal temperature is raised to 80 ° C. while introducing nitrogen gas. On the other hand, 500 g of a monomer mixture consisting of 250 g of methyl methacrylate, 200 g of n-butyl methacrylate, and 50 g of methacrylic acid was mixed with 250 g of distilled water and a polymerizable surfactant [Adecaria Soap SE-10N manufactured by Asahi Denka Kogyo KK). "] Of 20
g of the mixed solution, stirred and dispersed, and further prepared a mixed solution in which 1 g of ammonium persulfate was dissolved. This mixed solution was added to the flask maintained at a temperature of about 80 ° C. from the above separating funnel over 3 hours with stirring, and the polymerization was terminated at the 5th hour to obtain an emulsion polymerization solution. To the obtained emulsion polymerization liquid, 500 g of distilled water and a red dye [“AIZEN CATHILON PINK manufactured by Hodogaya Chemical Industry Co., Ltd.”
FGH "] was added thereto, and the uniformly mixed liquid was gradually heated and heated at 90 ° C. for 2 hours to obtain an aqueous dispersion of colored resin fine particles for an ink. After standing to cool, 3000 g of distilled water and 500 g of propylene glycol were added, and the mixture was stirred uniformly to obtain a red ink composition having a viscosity of 2.5 cP and a surface tension of 53 dyn / cm. The pen did not cause clogging, the written characters were excellent in water resistance and light resistance, exhibited a clear red color without bleeding, and the particle diameter of the colored polymer in the composition was 0.15 μm.

Example 2 A 2 liter flask was equipped with a stirrer, reflux condenser, thermometer, nitrogen gas inlet tube, 500 ml separatory funnel for charging monomer, set in a hot water tank, and charged with 250 g of distilled water. Then, the internal temperature is raised to 80 ° C. while introducing nitrogen gas. On the other hand, styrene 20
0 g, n-butyl methacrylate 200 g, acrylic acid 1
500 g of a monomer mixture consisting of
A mixture of 50 g and 10 g of a polymerizable surfactant (“Latemul S-180” manufactured by Kao Corporation) was mixed, stirred and dispersed, and further, 2 g of ammonium persulfate was dissolved to prepare a mixed solution. The mixture was cooled to a temperature of 8 from the separatory funnel.
The mixture was added to the flask maintained at about 0 ° C. with stirring over 3 hours, and the polymerization was terminated at the 5th hour to obtain an emulsion polymerization liquid.
To the obtained emulsion polymerization solution, 500 g of distilled water and a blue dye [“AIZEN VICTORI” manufactured by Hodogaya Chemical Industry Co., Ltd.
A PURE BLUE BOH "]
The uniformly mixed liquid was gradually heated and heated at 95 ° C. for 2 hours to obtain an aqueous dispersion of colored resin fine particles for ink. After allowing this aqueous dispersion of colored resin fine particles to cool naturally, 3000 g of distilled water and 50 g of propylene glycol were added.
0 g was added and stirred uniformly to obtain a blue ink composition having a viscosity of 2.8 cP and a surface tension of 56 dyn / cm. The pen using the obtained blue ink composition does not cause clogging,
The written character was excellent in water resistance and light resistance, and exhibited a clear blue color without bleeding. The particle diameter of the colored polymer in the composition was 0.20 μm.

[Comparative Example 1] Water-soluble acrylic resin ["JONCRYL 61J" manufactured by Johnson Polymer Co., Ltd.]
(Solid content 30%)] and a red dye [“AIZEN CATHILON PIN” manufactured by Hodogaya Chemical Industry Co., Ltd.
K FGH "], 10 g of propylene glycol
g and 64 g of distilled water, and stirred and dissolved for 1 hour to obtain a red ink composition.

[Comparative Example 2] Blue dye ["AIZEN VICTORIA PURE" manufactured by Hodogaya Chemical Industry Co., Ltd.
BLUE BOH ″], 10 g of propylene glycol, and 89 g of distilled water, and stirred and dissolved for 1 hour to obtain a blue ink composition.

[Comparative Example 3] 1 of a polymerizable surfactant [“Adekaria Soap SE-10N” manufactured by Asahi Denka Kogyo KK]
A red ink composition was prepared under the same conditions as in Example 1 except that 0 g was changed to a surfactant (6 g of sodium dodecylbenzenesulfonate and 4 g of polyoxyethylene nonylphenyl ether). The obtained ink composition had a viscosity of 2.8 cP and a surface tension of 38 dyn / cm. The particle diameter of the colored polymer in the ink composition is 0.23 μm
m.

Comparative Example 4 An ink composition was prepared under the same conditions as in Example 2 except that no heat treatment was performed.

[0026]

[Table 1]

[0027]

The aqueous ink composition for a writing instrument of the present invention has excellent storage stability and does not deteriorate for a long time. In addition, by using this aqueous ink composition for a writing instrument, it is possible to obtain characters and drawing lines which are clear, do not bleed or disappear due to water or sweat, and have excellent light resistance.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Seiwa Sakurai 1091 Tateishi, Fujioka City, Gunma Prefecture Mitsubishi Pencil Co., Ltd. R & D Center

Claims (4)

[Claims] 1. An aqueous dispersion of colored resin fine particles for ink obtained by heat-treating a solution obtained by dissolving a water-soluble dye in an emulsion polymerization solution obtained by emulsion polymerization of a vinyl monomer in the presence of a polymerizable surfactant. 2. The aqueous dispersion of colored resin fine particles for ink according to claim 1, wherein the heat treatment is performed under pressure. 3. An aqueous dispersion of colored resin fine particles for ink obtained by heat-treating a solution obtained by dissolving a water-soluble dye in an emulsion polymerization solution obtained by emulsion polymerization of a vinyl monomer in the presence of a polymerizable surfactant, An aqueous ink composition for a writing instrument, comprising a water-soluble organic solvent and water. 4. An aqueous dispersion of colored resin fine particles for ink comprising 3
~ 30% by weight (in terms of resin solid content), water-soluble organic solvent
The aqueous ink composition for a writing instrument according to claim 3, which contains 80% by weight and 30 to 90% by weight of water.