JPH0564671B2 - - Google Patents

Description

[Detailed description of the invention]

(1) Purpose of the invention [Field of industrial application] The present invention relates to a fluorescent ink, which has recently been widely used in the field of water-soluble fluorescent inks for writing instruments, stamps, etc. among stationery-related products. This invention relates to a fluorescent ink useful for heat-sensitive and pressure-sensitive recording paper. [Prior art] In general, the properties that ink filled in writing instruments such as felt pens, felt-tip pens, ballpoint pens, and brush pens should have are that the ink flows out smoothly from the pen tip, that the ink does not dry at the pen tip, Examples include not causing clogging and not solidifying in the writing instrument due to changes over time. In addition, the desirable properties for printing after writing are that the color tone is clear;
It has excellent water resistance and light resistance, does not set off or penetrate too much into the writing base material, and is compatible with the printed surface of pressure-sensitive and thermal paper that has developed with the recent development of information recording paper. On the other hand, there is no decolorizing or discoloring effect. Conventionally, fluorescent inks have been manufactured using fluorescent dyes, dye carriers, organic solvents, and water as main components. For example, JP-A-51-127730, JP-A No. 51-131727
As is clear from No. 51-66030, alkali aqueous solutions of hydroxypyrene sulfonic acid, polypropylene glycol, triazine-formaldehyde resins, alkali-soluble resins, etc. are used as dyeing agents. The water-based fluorescent ink produced by these methods has excellent characteristics such as clear color tone, fluorescent intensity, smooth ink flow, and storage stability. It has the effect of decoloring and discoloring printing on paper-related pressure-sensitive and thermal paper, etc.
Moreover, it has major drawbacks in water resistance and light resistance. Furthermore, it is already known that acrylonitrile polymers can be colored with dyes as cyano group-containing vinyl monomers, and this type of polymer is known to have excellent sunlight fastness. It has the disadvantage of lacking clarity. [Problem to be solved by the invention] With the recent spread of information recording paper-related water-based fluorescent inks, there is no decolorization or discoloration of printed characters, good water resistance and light resistance, and moreover, water-based fluorescent inks are superior to conventional fluorescent inks. The purpose is to provide an ink that does not impair properties, flowability, color development, storage stability, etc. (2) Structure of the Invention [Means for Solving the Problems] The present inventors have completed the present invention as a result of intensive studies on the problems of the above-mentioned prior art. That is, the present invention provides a cyano group-containing vinyl monomer.
(A) 20-80% by weight, the following vinyl monomer (B) 0.5-20
Weight% and particle size obtained by emulsion polymerization of a monomer mixture consisting of vinyl monomers (C) other than these
This invention relates to a fluorescent ink made by dyeing an emulsion polymer with a size of 0.5 microns or less with a fluorescent dye. Vinyl monomer (B): hydroxyl group, carboxyl group, amino group,
A vinyl monomer comprising a vinyl monomer having one or more groups selected from carbamoyl groups and groups derived from these, and a vinyl monomer having a sulfonic acid group or a salt thereof. ○ Emulsion polymer The emulsion polymer used in the present invention is a specific monomer.
The particles are obtained by emulsion polymerization of a monomer mixture consisting of (A), (B) and (C) and have a particle size of 0.5 microns or less, preferably 0.3 microns or less.
When the particle size of the emulsion polymer exceeds 0.5 microns,
The emulsion polymer settles in the fluorescent ink, resulting in poor long-term storage stability and the fluorescent ink not flowing smoothly. ○ Cyano group-containing vinyl monomer (A) The cyano group-containing vinyl monomer (A) may be any vinyl monomer containing a cyano group, but typical examples include acrylonitrile and methacrylate. Lonitrile can be given. The usage ratio of the cyano group-containing vinyl monomer (A) is:
20 to 80% by weight in the monomer mixture, preferably 25 to 60% by weight. If the proportion of the monomer (A) used is less than 20% by weight in the monomer mixture, the coloring by the dye will be insufficient, the clarity of the color tone and the fastness to sunlight will decrease,
If it exceeds 80% by weight, emulsion polymerization becomes difficult and storage stability deteriorates. ○ Vinyl monomer (B) Vinyl monomer (B) is a vinyl monomer having one or more groups selected from hydroxyl group, carboxyl group, amino group, carbamoyl group, and groups derived from these. It consists of a monomer and a vinyl monomer having a sulfonic acid group or a salt thereof,
Examples of the vinyl monomer having a sulfonic acid group or a salt thereof include vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, p-styrenesulfonic acid, acrylamide methylpropanesulfonic acid, and sodium salts thereof. , potassium salt, lithium salt, ammonium salt and the like. The vinyl monomer (B) is commercially available as a reactive emulsifier, such as Eleminol JS-2 (trade name manufactured by Sanyo Chemical Industries, Ltd.) and Latemul S-180 (Kao Chemical Co., Ltd.).
Co., Ltd. product name) etc. are also used. The other vinyl monomer (B) is one selected from a hydroxyl group, a carboxyl group, an amino group, a carbamoyl group, and a group derived therefrom.
It is a vinyl monomer having more than one type of group, and specific examples thereof include acrylic acid or methacrylic acid (hereinafter acrylic and methacrylic are collectively referred to as (meth)acrylic), β-hydroxyethyl (meth)acrylic acid, etc. Acrylate, ω-hydroxypropyl (meth) aquaacrylate, glycidyl (meth)acrylate, (meth)acrylamide, N
-Methylol (meth)acrylamide, N-butoxy (meth)acrylamide, dimethylaminoethyl (meth)acrylate, vinylpyridine and the like. When the monomer (B) having a group derived from each of the above-mentioned functional groups is an acid or basic substance having a carboxyl group or an amino group, it is necessary to neutralize it. This applies to the salt obtained by Monomer (B) has a dyeability improving function and dye receptivity (adsorption property). The vinyl monomer (B) can be used in one kind or two or more kinds, and the usage ratio is 0.5 to 20% by weight and 2 to 12% by weight in the monomer mixture.
is preferred. The usage ratio of vinyl monomer (B) is 0.5
If it is less than 20% by weight, it will not be possible to obtain a clear and highly concentrated fluorescent ink, and if it exceeds 20% by weight, emulsion polymerization will be difficult, there will be a large amount of residual monomer, and there will be a strong pungent odor, making it unsuitable as an ink. ○Other vinyl monomers (C) Vinyl monomers (C) are vinyl monomers other than the above vinyl monomers (A) and (B), such as styrene, α- Methyl styrene, vinyl toluene, vinyl acetate, vinyl propionate, propyl vinyl ether, butyl vinyl ether, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tertiary butyl acrylate, 2-ethylhexyl acrylate , acrylates such as cyclohexyl acrylate, decyl acrylate, benzyl acrylate, furfuryl acrylate, methyl methacrylate, ethyl methacrylate, n-
Methacrylates such as propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tertiarybutyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, decyl methacrylate, dodecyl methacrylate, benzyl methacrylate, furfuryl methacrylate, divinylbenzene, diallyl phthalate, Examples include compounds having two or more polymerizable unsaturated groups, such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate. Among these, monomers that give hard polymers such as styrene, methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate are preferably used. The proportion of the vinyl monomer (C) used in the monomer mixture is preferably 20 to 80% by weight, more preferably 40 to 70% by weight. If the proportion of monomer (C) used is less than 20% by weight, emulsion polymerization tends to be difficult and it is difficult to obtain a fluorescent ink with good storage stability;
If it exceeds 20%, it becomes difficult to obtain clear fluorescent ink with high sunlight fastness. The emulsion polymer used in the present invention can be obtained by emulsion polymerizing a monomer mixture consisting of the above monomers (A), (B) and (C). The emulsion polymerization method in the present invention is carried out by appropriately selecting the type and amount of surfactant depending on the purpose, but the polymerization temperature is preferably 50 to 90°C. Surfactants preferably used in the present invention include alkylbenzenesulfonates, alkylphenolsulfonates, sulfonates having an alkyldiphenyl ring, formalin condensates of alkylarylsulfonic acids, and ketone compounds of alkylarylsulfonates. , anionic surfactants such as sulfosuccinic acid ester salts, polyoxyethylene alkyl sulfonate salts, fatty acids and esters such as glycerin, glycol, pentaerythritol, sorbitan, or mannitan, or polyethylene oxide and higher fatty acids, higher alcohols, There are nonionic surfactants such as higher alkylamines or condensates with alkylphenol phosphoric acids, and there are cases where only anionic surfactants are used and cases where nonionic surfactants are used. Further, as the polymerization initiator, ammonium persulfate, potassium persulfate, hydrogen peroxide, etc. can be used, or if necessary, a reducing agent can be used in combination with these. ○ Coloring with fluorescent dyes The fluorescent dyes used in the present invention are selected from various dye groups such as basic dyes (including catilone dyes), acid dyes, direct dyes, disperse dyes, oil-soluble dyes, and fluorescent whitening dyes. However, it is particularly useful to use one or more types of daylight fluorescent dyes, and combinations of daylight fluorescent dyes and ordinary dyes (dyes without fluorescence) or pigments, but are not limited to these. . For example, there are the following. Both are color index numbers (CI)
BASIC YELLOW1, BASIC
YELLOW40, BASIC RED1, BASIC RED13,
BASIC VIOLET7, BASIC VIOLET10,
BASIC ORANGE22, BASIC BLUE7, BASIC
GREEN1, ACID YELLOW3, ACID
YELLOW7, ACID RED52, ACID RED77,
ACID RED87, ACID RED92, ACID BLUE9,
DISPERSE YELLOW121, DISPERSE
YELLOW82, DISPERSE ORANGE11,
DISPERSE RED58, DISPERSE BLUE7,
DIRECT YELLOW85, DIRECT ORANGE8,
DIRECT RED9, DIRECT BLUE22,
DIRECT GREEN6, FLUORESCENT
BRIGHTENING AGENT55,
FLUORESCENT BRIGHTENING WHITEX
WS52, FLUORESCENT162,
FLUORESCENT112, SOLVENT
YELLOW44, SOLVENT RED49, SOLVENT
BLUE5, SOLVENT PINK, SOLVENT
GREEN7, PIGMENT BLUE15, PIGMENT
GREEN7, PIGMENT RED53, PIGMENT
Examples include RED57, PIGMENT YELLOW1, etc., but among these, BASIC YELLOW40,
BASIC RED1, BASIC VIOLET10, ACID
YELLOW7, ACID RED92, ACID BLUE9,
DISPERSE YELLOW121, DISPERSE
BLUE7、DIRECT YELLOW85、
FLUORESCENT BRIGHTENING WHITEX
WS52, SOLVENT YELLOW44, SOLVENT
BLUE5 is preferred. Coloring with these dyes can be carried out either during emulsion polymerization or after polymerization. Regarding the conditions, 40 to 110℃ under atmospheric pressure or pressurization,
It is preferable to leave the mixture under stirring for 1 to 5 hours, and the amount of dye used is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the emulsion polymer (solid content). Coloring with a dye can be carried out by a conventional method, but it is preferable to use a surfactant.If the emulsion polymer is anionic or nonionic, regardless of the type of dye, the surface The activator is preferably anionic or nonionic. The polarities of the emulsion polymer, dye, and surfactant are appropriately selected depending on the purpose. The present invention uses the following hydrophilic organic solvents during and after the reaction to adjust the flowability of the fluorescent ink, the drying speed at the pen tip, the heat retention property, the viscosity, and the long-term use. Improves storage stability and writing characteristics. That is, alcohols, polyhydric alcohols and their derivatives, glycol ethers, nitrogen compounds, sugars, etc., such as isopropyl alcohol, n-butyl alcohol, ethylene glycol, diethylene glycol, propylene glycol monoethyl ether, ethylene glycol monobutyl ether, formamide,
These include N,N-dimethylformaldehyde, acetamide, triethanolamine, monoethanolamine, dimethyl sulfoxide, sugar rose, urea, trimethylolpropane, neopentyl glycol, polyethylene glycol, polypropylene glycol, and the like. Further, by adding and mixing a water-soluble polymer resin as shown below, it becomes an agent for adjusting the adhesion to the writing base material and the viscosity. For example, polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, 2-pyrrolidone, water-soluble melamine resin, water-soluble epoxy resin, water-soluble alkyd resin,
There are various water-soluble resins and emulsions such as water-soluble urea resins, water-soluble acrylic resins, acrylic emulsions, vinyl acetate emulsions, and butadiene emulsions. In addition to the above ingredients, the ink composition includes a nonionic activator,
If you mix surfactants such as anionic surfactants, dye solubilizers, leveling agents, preservatives, gas anti-fading agents, ion sequestrants, antioxidants, ultraviolet absorbers, antifoaming agents, etc. The synergistic effects of the physical and scientific actions of the two can be used to adjust viscosity and surface tension, improve hue retention, freshness, and sunlight fastness, and improve writing characteristics. ○ Examples and Comparative Examples Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Note that the performance test in each example was conducted in accordance with the following method. (Storage stability test) Place the marking pen in a constant temperature bath at 45°C and measure the number of days until it becomes impossible to write. (Nib drying test) Leave the felt pen open in a constant temperature and humidity bath at 20°C and 50% ± 5% for 5 hours, then print on writing paper to examine its writing performance and handwriting condition. . (Clearness of color tone) Handwriting written on writing paper is measured using a fluorescence spectrophotometer (light source: halogen lamp). (Lightfastness test) Handwriting written on writing paper was measured using a fade meter.
Measured by irradiation for 10 hours. (Water resistance test) Handwriting written on writing paper is immersed in water for 1 hour, and the degree of blurring of the handwriting is visually confirmed. (Influence on printing of pressure-sensitive paper) A line is written directly on the printing of commercially available pressure-sensitive paper, and the effect on the printing is visually observed after 3 minutes. Example 1 A 2-liter 4-necked flask was equipped with a cooling tube, a thermometer, a 500 c.c. separating funnel for monomer injection, and a stirring device, and set in a hot water tank, and 400 g of water was added to bring the internal temperature to 80°C. It was kept warm until. On the other hand, acrylonitrile
A monomer mixture consisting of 150 g of styrene, 90 g of styrene, 4 g of methacrylic acid, and 6 g of sodium styrene sulfonate was mixed and dispersed in a mixed solution of 400 g of water and 5 g of sodium lauryl sulfate, and then 2 g of ammonium persulfate was dissolved. The mixture was added from the liquid funnel into the flask with stirring over 3 hours, and the polymerization was completed in 5 hours. A mixture of 135 g of water, 200 g of ethylene glycol, 4 g of Rhodamine B (trade name manufactured by Sumitomo Chemical Co., Ltd.), 1 g of polyoxyethylene nonylphenol ether, and 5 g of sodium lauryl sulfate was added to the obtained emulsion polymer under stirring at room temperature. After mixing evenly,
When the temperature is gradually raised and dyed at 95°C for 2 hours, the particles become 0.2 microns, the viscosity is 10 cps (at 25°C), and the result is pressure-sensitive paper resistance.
A clear pink fine particle dispersed fluorescent ink was obtained which had excellent water resistance and light resistance, and was free from ink flow and clogging at the pen tip. Example 2 A 2-liter four-necked flask was equipped with a cooling tube, a thermometer, a 1-liter separating funnel for adding monomer, and a stirring device, and set in a hot water bath. 500g of water, 1g of polyoxyethylene nonylphenol ether, 150g of ethylene glycol,
Add 5 g of Maxilon Brilliant Rabin 10GFF (trade name, Ciba Geigy), 1 g of Rhodamine B (trade name, manufactured by Sumitomo Chemical Co., Ltd.), and 1 g of Rhodamine F4G (trade name, manufactured by Sumitomo Chemical Co., Ltd.), and bring the internal temperature to 80. The temperature was kept at ℃. Meanwhile, 120g of methacrylonitrile, 80g of styrene,
A monomer mixture consisting of 5 g of hydroxyethyl methacrylate, 2 g of methacrylic acid, and 4 g of sodium styrene sulfonate was mixed and dispersed in a solution of 120 g of water and 10 g of sodium polyoxyethylene alkyl sulfate, and further 3 g of ammonium persulfate was dissolved. This was added from the separatory funnel into the flask with stirring over 3 hours, and the polymerization was completed in 5 hours. The resulting product has particles of 0.17 microns, a viscosity of 5 cps (at 25°C), pressure-sensitive paper resistance, water resistance,
It exhibits excellent light resistance and ink flowability.
It was a bright orange fine particle dispersed fluorescent ink that did not clog the pen tip. Comparative Example 1 Styrene-acrylic acid copolymer 5g Ethylene glycol monoethyl ether 10g Ethylene glycol 20g Rhodamine B 0.2g Water 74.7g A pink fluorescent water-based ink was prepared by adjusting the pH to 8.5 with a 10% aqueous sodium carbonate solution to the above ingredients. Obtained. Comparative Example 2 Water-soluble melamine resin (solid content 60% aqueous solution) 30g Ethylene glycol monoethyl ether 10g Ethylene glycol 20g Maxilon Brilliant Yellow 0.5g Rhodamine 6GCP 0.2g Water 39g By stirring and dissolving the above components at room temperature for 1 hour, an orange color was obtained. A fluorescent water-based ink was obtained. Comparative Example 3 Hydroxypyrene trisulfonic acid 1.5 g Triethanolamine 10 g Diethylene glycol 20 g Water 68.5 g The above components were stirred and dissolved at room temperature to obtain a yellow fluorescent water-based ink. Performance tests were conducted for each of the above Examples and Comparative Examples. The results are shown in Table 1.

[Table] (3) Effects of the invention The fluorescent ink of the invention has excellent color clarity, storage stability, drying resistance of the pen tip, water resistance, and light resistance.
It does not affect printing on pressure-sensitive paper, and even if you freely mark printing on information recording paper, which will become increasingly popular in the future, it will not fade or change color over time and will maintain its clarity. Therefore, it is particularly useful for such writing instruments.

Claims (1)

[Scope of Claims] 1. 20 to 80% by weight of a cyano group-containing vinyl monomer (A), 0.5 to 20% by weight of the following vinyl monomer (B), and vinyl monomers other than these (C) A fluorescent ink obtained by dyeing an emulsion polymer with a particle size of 0.5 microns or less obtained by emulsion polymerization of a monomer mixture consisting of the following with a fluorescent dye. Vinyl monomer (B): hydroxyl group, carboxyl group, amino group,
A vinyl monomer comprising a vinyl monomer having one or more groups selected from carbamoyl groups and groups derived from these, and a vinyl monomer having a sulfonic acid group or a salt thereof.