JPS62197477A - Ink composition for writing board - Google Patents

Abstract

PURPOSE:To obtain the titled composition having excellent erasability and long-term stability, by dissolving a mixture of a specified colored polymer with a hydrophobic nonionic surface active agent, a hydrophilic nonionic surface active agent, an ampholytic surface active agent, a silicone oil, etc. in a volatile organic solvent. CONSTITUTION:A colored polymer (A) is obtained by dyeing with a basic dye a copolymer resin which is prepared by copolymerizing an ethylenically unsaturated sulfonic acid (salt) with another copolymerizable monomer, contains 0.1-60wt% sulfo groups or salt thereof, has a glass transition temperature of -20-150 deg.C, and is soluble in an organic solvent. 100pts.wt. component A is mixed with additives (B) comprising 5-100pts.wt. hydrophobic nonionic surface active agent (a), 5-100pts.wt. hydrophilic nonionic surface active agent (b) with a + b being 10-150pts.wt., 5-100pts.wt. ampholytic surface active agent (c), 0-20pts.wt. silicone oil (d), 0-50pts.wt. hardly volatile alcoholic solvent (e), and 10-150pts.wt. hardly volatile or non-volatile organic compound (f). This mixture is dissolved in a volatile organic solvent in an amount sufficient to provide a concentration of 4-50wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ink composition for a writing board, and more specifically, the present invention relates to an ink composition for a writing board. The present invention relates to an ink composition for writing boards that has the ability to be easily erased by gently wiping with paper or the like.

[Conventional technology]

Conventionally, this type of ink for writing boards has been prepared by using pigments or dyes as colorants, and dispersing or dissolving a resin as a binder and an additive for achieving erasability in an organic solvent. When pigments are used, they are difficult to stain on the writing board and have good erasability, but the degree of dispersion of the pigments tends to be uneven5, and stability is poor, and the color of the ink becomes lighter during storage. There were problems with long-term stability.

On the other hand, when dyes are used, although there is no problem with stability during storage, if handwriting is left unwiped for a long period of time, the dye tends to stain the writing board, causing the handwriting to disappear completely. There were problems such as making it difficult to wipe off.

[Problems to be Solved by the Invention] An object of the present invention is to provide an ink for writing boards that is excellent in both erasability and long-term stability, which have been problems in the past.

[Means for solving problems]

The gist of the present invention is as follows: 100 parts by weight of a colored polymer obtained by dyeing a resin having a sulfonic acid group or a salt thereof and soluble in an organic solvent with a basic dye; additives (A) a hydrophobic nonionic surfactant; 5 to 100 parts by weight, (B) hydrophilic nonionic surfactant 5 to 100 parts by weight, total amount of (A) and (B) is 10 to 150 parts by weight, (0) zwitterionic surfactant 5 ~100 parts by weight, (D) silicone oil 0-20
Parts by weight, (0 to 50 parts by weight of hardly volatile alcoholic solvent and (IF) 10 parts by weight of hardly volatile or non-volatile organic compound
A mixture of ~150 parts by weight is added to a volatile organic solvent of ~150 parts by weight.
An erasable ink composition for a writing board comprising 50% by weight.

The present invention will be explained in detail below.

The organic solvent-soluble resin having a sulfonic acid group or a salt thereof in the present invention can be produced by various methods. For example, it can be obtained by a commonly known method of sulfonating a resin, or by copolymerizing one or more ethylenically unsaturated sulfonic acids or salts thereof with one or more copolymerizable monomers. Examples of the ethylenically unsaturated sulfonic acid or its salt here include styrene sulfonic acid, vinylbenzyl sulfonic acid, vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, and acryloyloxyethyl sulfonic acid.

Unsaturated sulfonic acids such as methacryloyloxypropylsulfonic acid 92-acrylamido-2-methylpropanesulfonic acid and salts thereof, such as lithium salts, sodium salts, potassium salts, and ammonium salts, can be mentioned. Examples of monomers copolymerizable with these include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and dodecyl acrylate.

Acrylic acid esters such as 2-hydroxyethyl acrylate and glycidyl acrylate: methyl methacrylate, ethyl methacrylate, globil methacrylate,
Butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, 2-hydroxyethyl methacrylate.

Methacrylic acid esters such as glycidyl methacrylate: In addition to vinyl esters such as vinyl acetate and vinyl gropionate, examples include styrene, butadiene-9-chloroprene, vinyl chloride, and the like.

The copolymerization ratio of one or more types of ethylenically unsaturated sulfonic acid or its salt in the copolymer used in the present invention can be freely selected, but if the ratio of ethylenically unsaturated sulfonic acid or its salt is too high, the solubility in organic solvents will increase. decreases. To obtain a dark coloring material, usually (L1 to 60% by weight, particularly preferably CL1 to 40% by weight is selected).Furthermore, the glass transition temperature of the copolymer is 120°C or more and 150°C or less, more preferably The ratio is preferably in the range of 0°C or more and 120°C or less.If the temperature is less than -20°C, handwriting written on the writing board tends to be sticky, and the coating strength is weak and does not have sufficient erasability. When the temperature exceeds 150°C, handwriting tends to form a uniform film (sufficient writing performance is likely to be lost).

The copolymer is prepared by mixing the above monomers in an organic solvent in the presence or absence of a basic dye with a conventional radical polymerization initiator, for example, a persulfate such as potassium persulfate or ammonium persulfate, kiemene hydroperoxide, t - Polymerization is carried out by introducing each component together with an organic peroxide such as butyl hydroperoxide or an azo compound such as azobis-dibutyronitrile or azobisdimethylvaleronitrile into a polymerization vessel under stirring, all at once, partially or continuously. You can get it by doing. The polymerization temperature may be lower than the boiling point of the medium. Although the concentration of the monomer can be freely selected, it is generally 3 to 50% by weight, usually 10 to 30% by weight. Polymerization at high concentrations is not preferred because the viscosity of the polymerization system becomes high and it becomes difficult to remove the heat of polymerization. Furthermore, polymerization at too low a concentration is not preferred for economic reasons.

For the purpose of the present invention, there are no restrictions on the method of producing such a polymer.

When polymerizing in the absence of a basic dye, the polymer obtained by polymerization is then dyed with a basic dye. Basic dyes (in this specification, it is broadly defined to also mean "cationic dyes") include the usual triphenylmethane, azo, and methine dyes.

Any of oxazine-based dyes and anthraquinone-based dyes may be used, and dyeing can be carried out using conventional methods. That is, the polymer solution obtained by polymerization is preferably adjusted to pH
A method may be used in which the dye is added after adjusting the pH to 2 to 7, more preferably 3 to 5.

In addition, when a colored polymer solution is obtained by the presence of a basic dye in the polymerization system, the pH of the polymerization system is preferably adjusted to pH 2 to 7, more preferably pH 5, taking into account the dye's discoloration and fading stability. It is desirable to carry out at ~5. In any case, in dyeing the polymer of the present invention with a basic dye, such dyeing conditions are not limited in view of the spirit of the present invention.

Although the concentration of the colored polymer thus produced can be freely selected, it is usually adjusted to 1 to 30% by weight, particularly preferably 5 to 20% by weight, based on the ink composition. At high concentrations, the viscosity of the solution becomes too high, which is not practical. At low density, the color density is low (unfavorable).

The volatile organic solvent for dissolving the colored polymer in the present invention may be any one conventionally used in marking pen ink compositions. For example, ethyl alcohol, n-propyl alcohol, isopropyl alcohol.

n-butyl alcohol, gec-butyl alcohol.

tart-butyl alcohol, isobutyl alcohol,
Boiling point of ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, etc. 150℃
alcoholic solvents, ester solvents such as nibutyl acetate, ethyl acetate and butyl propionate, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and diisobutyl ketone, aromatic solvents such as xylene and toluene, etc. When using a solvent other than alcohol, it is preferable to mix an alcohol solvent or a polar solvent such as N-methyl-2-pyrrolidone or r-butyrolactone at 10°C in order to increase the solubility of the colored polymer. These solvents have a concentration of 50% relative to the ink composition.
96% by weight. Outside this range, an appropriate viscosity for the ink composition cannot be obtained.

Recently, among the volatile organic solvents mentioned above, there is a trend that non-alcohol-based solvents are not preferred due to their odor and toxicity, and it is desired to use safer alcohol-based solvents. In the invention, if a colored polymer obtained by dyeing a polymer having an alcohol-soluble sulfonic acid group or its salt with a basic dye is used, an ink composition for a writing board using an alcohol-based solvent can be provided. In this case, the method for producing a polymer having an alcohol-soluble sulfonic acid group or its salt is a commonly known method of sulfonating an alcohol-soluble resin, or a method of producing an ethylenically unsaturated sulfonic acid group or a salt thereof. Monomers capable of providing alcohol-soluble resins with their salts, such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate.

Polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate,
Propyl methacrylate, butyl acrylate, butyl methacrylate, etc. (the former 6 are a group of monomers (A) that give hydrophilic polymers).

The latter six are a monomer group (B) that can provide a hydrophobic polymer. ) and, if desired, other monomers copolymerizable with these to the extent that alcohol solubility is not impaired. In addition, when such an alcohol-soluble resin is used, the monomers to be copolymerized with ethylenically unsaturated sulfonic acid or its salt include 90% by weight or less of the monomers of group (A) shown above, and group (B). When a copolymer containing 10% by weight or more of monomers is used, hydrophobicity is imparted to the resin, and the hygroscopicity of the resin is suppressed. In other words, a more suitable ink composition is provided since handwriting does not become sticky and erasability is improved.

Next, the additives in the present invention will be described.

In the present invention, the additive (A) hydrophobic nonionic surfactant is 5 to 10 parts by weight per 100 parts by weight of the colored polymer.
0 parts by weight, (B) hydrophilic nonionic surfactant 5 to 10
0 parts by weight, and the total amount of (A) and (B) is 10 to 150 parts by weight, (0) zwitterionic surfactant 5 to 100 parts by weight,
(D) 0 to 20 parts by weight of silicone oil, (E) 0 to 50 parts by weight of a hardly volatile alcoholic solvent, and (F) 10 to 150 parts by weight of a hardly volatile or nonvolatile organic compound are used. Additives ((trans), (B), (o).

(?) Regarding Vc, if it is below this range, excellent erasability cannot be achieved, and if it exceeds this range, handwriting tends to be repelled on the writing board or become difficult to dry. When writing with ink containing these additives, if the handwriting tends to repel, adding additive (D) can prevent the tendency of the handwriting to repel.

Furthermore, the erasability can be further improved by adding the additive (1c).

The hydrophobic nonionic surfactant in the present invention includes:
Nonionic surfactants with an HLB of less than 13, such as polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene nonylphenol ether, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan tristearate Examples include stearate, polyoxyethylene sorbitan monooleate, and polyoxyethylene rubitan trioleate.

As the hydrophilic nonionic surfactant in the present invention,
Nonionic surfactants with HLB of 13 or more, such as polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene nonylphenol ether, as well as nonionic surfactants with ionic properties. , for example, @e of polyoxyethylene alkyl ether or polyoxy7ethylene alkyl phenol ether
Examples include ester, phosphoric acid ester of polyoxyethylene alkyl ethyl or polyoxyethylene alkylphenyl ether.

Examples of the zwitterionic surfactant in the present invention include dimethylsteroleptaine, dimethyllaurylbetaine, and alkylglycine.

Examples of the silicone oil in the present invention include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, as well as modified silicone oils such as polyether-modified, higher fatty acid-modified, and carboxyl-modified silicone oils.

Examples of the hardly volatile alcoholic solvent in the present invention include alcoholic solvents having a boiling point of 150° C. or higher, such as ethylene glycol, diethylene glycol, triethylene glycol, propylene gellicol, and glycerin.

The hardly volatile or non-volatile organic compound in the present invention is an organic compound having a boiling point of 180°C or higher and a melting point of 60°C or lower, such as dioctyl sepacate.

Dioctyl azelate, dioctyl adipate.

Examples include dibasic acid esters such as dioctyl phthalate, monobasic acid esters such as nibutyl stearate, butyl oleate, butyl epoxy stearate, and the like.

In the present invention, the additives mentioned above are added, but other release aids, such as anionic surfactants, organic amides, etc., and compounds added to ordinary marking inks, such as preservatives, are also added. .

Flavors etc. may be added.

〔Effect of the invention〕

In the ink composition of the present invention, since the dye is strongly bonded to the resin that functions as a binder, the dye can be easily peeled off from the writing board together with the resin that is the binder by wiping with cloth or paper. In addition, there is no dye staining on the writing board, and it can be easily wiped off for a long time.
Has characteristics.

Furthermore, unlike pigments, particles that are insoluble in a solvent are not dispersed, and because they are a uniform solution, they also have excellent long-term stability during storage.

As described above, according to the present invention, it is possible to obtain an ink for writing boards that can solve both the conventional problems of erasability and long-term stability.

[Implementation side]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited in any way by the description of these Examples.

Production Example: Under a nitrogen stream, 30 g of ethyl alcohol was placed in a polymerization container, heated while stirring, and raised to 80°C, followed by a monomer solution with the following composition and a catalyst solution in which 179 azobisisobutyronitrile was dissolved in 609 VC of ethyl alcohol. Polymerization was carried out by dropping each of these over 3 hours. Continued 9
Polymerization was continued at 0° C. for 2 hours to obtain an ethyl alcohol solution of a polymer having sulfonic acid groups. 5% by weight in this solution
Hydroxide) IJum ethyl alcohol solution 52.71
In addition, after adjusting the pH to 5, cationic dye Catilon Blue CD-PRLH (manufactured by Hodogaya Chemical Industry ■) 1309
was added, stirred at 70°C for 1 hour, cooled to room temperature, diluted with ethyl alcohol to a polymer concentration of 10% by weight, and filtered to obtain Production Examples 1 to 40 colored polymer solutions.

Furthermore, colored polymer 109 obtained by drying the colored polymer solution of Production Example 4 was dissolved in ethyl alcohol 109 and ethyl acetate 809 to obtain a colored polymer solution of Production Example 5 having a polymer concentration of 10% by weight.

Seventhmer solution 2-hydroxyethyl methacrylate of Production Example 1
5&3g butyl methacrylate
257g Spinomer Nags (?-Styrene Sulfate*1 Kidney Sodium Purity 81.9%, Toyo Soda Kogyo ■
(manufactured by) 1 & 69 ethyl alcohol
1409 water
909 production example 2
solution of 2-hydroxyethyl methacrylate)
7a09 spin? -N&s1)
16.69 ethyl alcohol
1409 water
909 Monomer solution of Production Example 3 2-hydroxypropyl methacrylate
62.49 Ethyl methacrylate
19.092-Crylamito=2-methylpropane Cζ ring size (/acid
1 179 ethyl alcohol
1309 water
5g Monomer solution of Production Example 4 Ethyl methacrylate 41
．． 79 methyl methacrylate
254924 crylamide = 2-methylglonoζl
1 579 ethyl alcohol
1309 water
5g Examples and Comparative Examples Production Examples 1 to 50 Add the additives shown in Table 1 to 100 parts by weight of the colored polymer solution (numbers are addition i[) expressed in parts by weight]
Next, this solution was filled into a marking pen and written on a commercially available enamel writing board to test the erasability of handwriting. Test at 25℃.

This was carried out using a commercially available eraser under conditions of 55% RH. The results are shown in Table 1 with the symbols ◎ for those that disappeared after rubbing lightly, ○ for those that disappeared after rubbing a little hard, Δ for those that disappeared after rubbing quite strongly, and × for those that are difficult to erase.

Next, as comparative examples, additives (A), (B), (
Table 2 shows the results when either C or (IF) is missing and when the alcohol-soluble resin and dye are simply mixed. As an alcohol-soluble resin, butyral resin (Denka Butyral 20QO- manufactured by Ki Kagaku Kogyo ■) was used as alcohol-soluble resin.
L) or ketone resin (byla manufactured by Hitachi Chemical Co., Ltd.) or 10 g of basic dye (Hodogaya Chemical Co., Ltd.)
Methylene Blue) 19 was dissolved in ethyl alcohol 899, the additives shown in Table 2 were added, and the erasability was evaluated in the same manner as before.

Table 1) As is clear from the results in Table 2, the ink composition for writing boards of the present invention exhibited good erasability.

The additives in the table will be explained below.

Emuldan 106: Polyoxyethylene lauryl ether (HLE = 1 cL5) Emulken 306 manufactured by Kao ■
P: Polyoxyethylene stearyl ether (manufactured by Kao ■)
HI, B = 9.4) Rheodor TWS-520: Kao ■
Made of polyoxyethylene sorbitan tristearate (
HLB=1 (L5) Emuldan 14F; Kao ■ polyoxyethylene lauryl ether (HLB=1 &3) Hitenol N-0
8- Polyoxyethylene alkyl ether sulfate ester amphitol 86B manufactured by Daiichi Kogyo Seiyaku ■: Dimethyl stearyl betaine anhydrol 24B manufactured by Kao ■: Dimethyl lauryl betaine silicone KIF355 manufactured by Kao ■ Polyether modified silicone oil manufactured by Shin-Etsu Chemical ■

Claims (6)

[Claims] (1) 100 parts by weight of a colored polymer obtained by dyeing a resin containing a sulfonic acid group or its salt and soluble in an organic solvent with a basic dye; additives (A) 5 to 100 parts of a hydrophobic nonionic surfactant; parts by weight, (B) 5 to 100 parts by weight of hydrophilic nonionic surfactant, and the total amount of (A) and (B) is 10
~150 parts by weight, (C) zwitterionic surfactant 5-10
0 parts by weight, (D) silicone oil 0 to 20 parts by weight, (
E) 0 to 50 parts by weight of a hardly volatile alcoholic solvent and (F) 10 to 10 parts by weight of a hardly volatile or nonvolatile organic compound
A mixture of 150 parts by weight is added to 4 to 5 parts by weight of a volatile organic solvent.
An erasable writing board ink composition prepared by dissolving 0% by weight. (2) The organic solvent-soluble resin having a sulfonic acid group or its salt is a copolymer obtained by copolymerizing ethylenically unsaturated sulfonic acid or its salt with other copolymerizable monomers. An ink composition for a writing board according to claim (1). (3) Claim No. 2, wherein the organic solvent-soluble resin having a sulfonic acid group or a salt thereof is a copolymer containing 0.1 to 60% by weight of a sulfonic acid group or a salt thereof.
) The ink composition for writing boards as described in item 1. (4) The ink composition for a writing board according to claim (3), wherein the organic solvent-soluble resin having a sulfonic acid group or a salt thereof has a glass transition temperature of -20°C or more and 150°C or less. . (5) The ink composition for a writing board according to claim (1) or (2), wherein the organic solvent-soluble resin having a sulfonic acid group or a salt thereof is alcohol-soluble. (6) The organic solvent-soluble resin having a sulfonic acid group or its salt is alcohol-soluble, and monomers copolymerized with ethylenically unsaturated sulfonic acid or its salt include (a) hydroxyethyl acrylate, hydroxy Monomer selected from ethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate: 90% by weight or less (b) Ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl The ink composition for a writing board according to claim (5), which is a copolymer consisting of 10% by weight or more of a monomer selected from methacrylates.