JP6736353B2 - Aqueous ink composition for writing board and writing instrument using the same - Google Patents

Description

The present invention relates to a water-based ink composition for a writing board, which is suitable for a writing board that is a non-absorbing surface such as a whiteboard and an enamel board, which is excellent in erasability and stability over time, and a writing instrument using the same.

The so-called water-based ink composition for a writing board up to now has a release agent and in some cases a release aid so that it can be easily wiped off with a soft dry cloth or paper when writing on a non-absorbing surface such as a whiteboard or an enamel board. Most of them contained an agent.

For example, 1) Water as a dispersion medium, a colorant, a binder made of a water-soluble synthetic resin or an acrylic synthetic resin emulsion, a silicone-based surfactant as a release agent, and a water-insoluble inorganic powder are contained in respective predetermined amounts. In the ink composition for a board marker (see, for example, Patent Document 1) or 2) an aqueous erasable marking pen ink composition obtained by emulsifying and adding a release agent, the storage stability is increased and In order to provide an aqueous erasable marking pen ink composition capable of retaining excellent erasability and writability even after being left for a long time, water as a solvent, a colorant, and a release agent are provided. An aqueous erasable marking pen ink composition containing an emulsion of an oily substance that is hardly volatile at room temperature, cyclodextrin or a derivative thereof, a resin, and a surfactant selected from sulfo fatty acid ester salts and polyoxyethylene ether ( For example, Patent Document 2) is known.

In these aqueous ink compositions for writing plates, when the erasability is attempted to be improved, the stability over time tends to be poor. On the other hand, when the stability is improved with time, the erasability tends to be deteriorated. At present, there has been a strong demand for the appearance of a water-based ink composition for a writing plate that is highly compatible with erasability and stability over time.

JP-A-2-124985 (claims, examples, etc.) JP-A-10-25442 (claims, examples, etc.)

The present invention, in view of the problems and the current situation of the above-mentioned conventional technology, is intended to solve this, erasability, excellent stability over time, whiteboard highly compatible with erasability and stability over time, An object of the present invention is to provide a water-based ink composition for a writing plate suitable for a writing plate which is a non-absorbing surface such as an enameled plate, and a writing instrument using the same.

The present inventor, in view of the above-mentioned conventional problems, as a result of earnest research, at least water, containing a colorant, by further containing a specific component, the aqueous ink composition for a writing plate of the above purpose and this. The inventors have found that the writing instrument used can be obtained, and completed the present invention.

That is, the aqueous ink composition for a writing plate of the present invention and a writing instrument using the same are as follows.
(1) A water-based ink composition for a writing plate, which contains at least water and a colorant and further contains 2 to 20 mass% of triacetin.
(2) The water-based ink composition for a writing plate as described in (1) above, wherein the water-soluble organic solvent is contained in the ink composition in an amount of 5 to 60% by mass.
(3) A writing instrument comprising the aqueous ink composition for a writing plate as described in (1) or (2) above.

According to the present invention, an erasability, excellent stability over time, a writing board aqueous solution suitable for a writing board that is a non-absorbing surface such as a whiteboard or an enameled plate, which is highly compatible with erasability and stability over time. An ink composition and a writing instrument using the same are provided.

Hereinafter, embodiments of the present invention will be described in detail.
The aqueous ink composition for a writing plate of the present invention is characterized by containing at least water and a colorant, and further containing 2 to 20% by mass of triacetin.

The colorant used in the present invention is not particularly limited as long as it is used for writing boards, and examples thereof include inorganic pigments such as carbon black and titanium dioxide, azo pigments, condensed polyazo pigments, and phthalocyanines. Organic pigments such as system pigments, metal complex pigments, thioindigo pigments, dye lake pigments, fluorescent pigments, and the like, and further processed pigments whose surface is processed by resin coating, for example, various types of Microlith A type, AS black, AS blue, IK red or the like can also be used. In addition to the above pigments, dyes such as acid dyes, basic dyes and direct dyes that can be dissolved in an aqueous medium can be used.

These colorants can be used alone or in admixture of two or more, and from the viewpoint of exhibiting sufficient line density, writability, and further good erasability, the content thereof is the ink The amount is preferably 1 to 30% by mass (hereinafter, simply referred to as “%”), and more preferably 2 to 20% with respect to the total amount of the composition.

The triacetin used in the present invention is used as a release agent component, and can greatly improve the erasability without impairing the temporal stability of the ink system.
Triacetin is also known as another name, triacetyl glycerol, 1,2,3-propanetriol triacetate, glyceryl triacetate, triacetyl glycerin, and the like. Specifically, for example, triacetin and others commercially available from each manufacturer, Includes reagents and those that comply with Japanese Pharmaceutical Additive Standards.

The content of this triacetin is preferably 2 to 20%, more preferably 5 to 15% with respect to the total amount of the ink composition.
When the content of this triacetin is less than 2%, the effect of the present invention cannot be exhibited, while when it exceeds 20%, the solubility of the polymer is lowered and the stability over time is impaired. Become.

In the present invention, in order to further stabilize the solubility of the above triacetin, it is preferable to include a water-soluble organic solvent.
Examples of the water-soluble organic solvent that can be used include alcohols (including modified and unmodified) such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, and t-butyl alcohol. , Glycerin, ethylene glycol, diethylene glycol, hexylene glycol, 1,3-butanediol, polyethylene glycol, propylene glycol, butylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol Examples thereof include monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether and the like.
It is preferable to use ethanol, n-propyl alcohol, isopropyl alcohol, or propylene glycol monomethyl ether from the viewpoint of excellent drying property.

These water-soluble organic solvents may be used alone or in admixture of two or more, and the content thereof is preferably 3 to 70%, more preferably 5% with respect to the total amount of the ink composition. -60%, particularly preferably 10-40% is desirable.
By setting the content of the water-soluble organic solvent to 3% or more, more preferably 5% or more, the solubility of triacetin can be further stabilized, while the content of the water-soluble organic solvent is 70% or less, By more preferably setting it to 60% or less, the stability over time can be further improved, and a stable ink that is less likely to cause writing smear can be obtained.
In addition, in the present invention, the balance is adjusted with water (tap water, purified water, distilled water, ion-exchanged water, pure water, ultrapure water, etc., as described below) as described below. From the viewpoint of stability balance, it is desirable that the mass ratio of water to the water-soluble organic solvent be 90:10 to 30:70.

In the present invention, in addition to the above-mentioned components, a fixing resin, a pigment dispersant, an anti-repellent agent, water and the like used in the aqueous ink composition for a writing board are contained.
The fixing resin used is used as a line-drawing fixing component and is not particularly limited as long as it is a water-soluble or water-dispersible resin used for writing boards, and examples thereof include polyvinyl alcohol (PVA) and its modified products. , Polyvinyl acetal resin, acrylic resin, polyacrylic acid, water-soluble styrene-acrylic resin, water-soluble styrene-maleic acid resin, polyvinylpyrrolidone, water-soluble maleic acid resin, water-soluble styrene resin, water-soluble ester-acrylic resin, ethylene- Maleic acid copolymers, water-soluble urethane resins, etc., and those selected from styrene acrylic resin emulsions, acrylic emulsions, vinyl acetate emulsions, urethane emulsions, styrene-butadiene emulsions, resin emulsions such as styrene acrylonitrile emulsions, etc. Each can be used alone or in combination of two or more. Preferably, a water-soluble resin is preferable from the viewpoint of further improving the erasability, and in particular, from the viewpoints of line-drawing fixability and erasability, polyvinyl acetal resins, commercially available products such as S-REC KW-1, KW-3 (Sekisui (Chemical Industry Co., Ltd.) is preferable.
The content of these fixing resins is preferably 1 to 10% as solid content with respect to the total amount of the ink composition.

The pigment dispersant used is not particularly limited as long as it improves the dispersibility when a pigment is used as a colorant, and examples thereof include acidic resins, basic resins, nonionic surfactants and anionic surfactants. Examples thereof include styrene-acrylic resin, styrene-maleic acid resin, polyvinyl-sulfonic acid resin fat, polyoxyethylene (POE) phytosterol, POE phytostanol, etc., alone or in combination of two or more. It can be mixed and used.
In particular, when the amount of the water-soluble solvent with respect to water is 50% or more, when POE phytosterol or POE phytostanol is used as the pigment dispersant, the dispersion stability is further improved.
The content of these pigment dispersants is preferably 1 to 10% with respect to the total amount of the ink composition.

The anti-repellent agent used includes, for example, polyether-modified silicone, a silicone-based surfactant such as polyethylene glycol (PEG)-3 dimethicone, a fluorine-based surfactant containing a perfluorobutanesulfonic acid group, and a lipophilic group. It is preferable that the fluorine-containing surfactant such as a fluorine-containing surfactant is contained in the ink composition in an amount of preferably 0.01 to 1.0%.

Furthermore, in the water-based ink composition for a writing plate used in the present invention, the balance is adjusted with water (purified water, distilled water, ion-exchanged water, pure water, ultrapure water, etc.) in addition to the above components, and further, To the extent that the effects of the present invention are not impaired, for example, a dry-up inhibitor, a handwriting anti-whitening agent, a viscosity modifier, an antiseptic agent or an antibacterial agent, a pH modifier, etc. are appropriately contained within the range that does not impair the effects of the invention. can do.

The aqueous ink composition for a writing plate of the present invention comprises, in addition to the above components, other components by stirring and mixing with a stirrer such as a homomixer, a homogenizer or a disper, and further, if necessary, filtration or centrifugation. The aqueous ink composition for writing boards can be prepared by removing coarse particles in the ink composition.

The water-based ink composition for a writing plate of the present invention is put to practical use by being mounted on a marking pen having a pen tip portion such as a fiber tip, a felt tip, and a plastic tip.
The structure of the marking pen is not particularly limited, and may be, for example, a structure having a retractable mechanism such as a knock type, a rotary type, or a slide type in addition to the cap type marking pen.

In the water-based ink composition for a writing plate of the present invention configured as described above, by containing at least water and a colorant and further containing 2 to 20% by mass of triacetin, the stability of the ink over time is excellent and a clear ink is obtained. For a writing board that is not impervious to whiteboard, resin plate, metal plate, enamel plate, glass plate, etc. Thus, a water-based ink composition suitable for a writing plate and a writing instrument using the same can be obtained.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples and the like.

[Examples 1 to 7 and Comparative Examples 1 to 5]
Water-based ink compositions for each writing board were prepared by a conventional method according to the composition shown in Tables 1 and 2 below.
The erasability and stability over time (initial viscosity and viscosity after lapse of time) of each of the obtained aqueous ink compositions for writing plates were evaluated by the following evaluation methods. The evaluation results are shown in Tables 1 and 2 below.

(Erasability evaluation method)
Each of the obtained ink compositions was filled in a writing pen marking pen (PWB-4M, manufactured by Mitsubishi Pencil Co., Ltd.), and written on a enamel plate (size 300×450 mm), and after 1 minute, a tissue was overlaid. A weight made of stainless steel was put on it, and the weight (g) when it could be erased was measured. The smaller the weight, the better the erasability.

(Evaluation method of stability over time)
The viscosity (25°C) of each aqueous ink composition for writing plates immediately after production and the aqueous ink composition for each writing plate were placed in a glass bottle, allowed to stand in a thermostatic layer at 50°C for 1 month, and then left at room temperature. The viscosity (25° C.) of the ink after the measurement was measured. For the viscosity measurement, an E-type viscometer (TV20 manufactured by Toki Sangyo Co., Ltd.) was used. The smaller the difference between the initial viscosity and the viscosity value after aging, the better the stability over time.

As is clear from the results of Tables 1 and 2, the water-based ink compositions for writing plates of Examples 1 to 7 according to the present invention are more erasable than Comparative Examples 1 to 5, which are outside the scope of the present invention. It has been found that an aqueous ink composition for a writing plate, which is excellent in stability over time, can be obtained.
When Comparative Examples 1 to 5 are individually viewed, Comparative Examples 1 to 3 are to be compared with Examples 1 to 3 and do not contain triacetin as a release agent, and Comparative Examples 4 and 5 are conventional. It was confirmed that the modified silicone oil which is the release agent of No. 1 or the emulsion of liquid paraffin is used, and in these cases, the effects of the present invention, that is, the erasability and the stability with time, cannot be highly compatible. The liquid paraffin emulsion of Comparative Example 5 was prepared by previously mixing 20% of liquid paraffin, 6% of Kao's Leodol 460V and 84% of purified water with a disper and then emulsifying with a PRIMIX homomixer MARK II at 8000 rpm for 10 minutes. It was stirred.

A water-based ink composition for a writing board suitable for a writing board which is a non-absorbing surface such as a whiteboard and an enamel board, and a writing instrument using the same are obtained.

Claims (3)

A water-based ink composition for a writing plate, comprising at least water and a colorant, further containing 3 to 70% by mass of a water-soluble organic solvent and 2 to 20% by mass of triacetin. Claim 1 for writing board aqueous ink composition according the content of water-soluble organic solvent, characterized in that 5 to 60 wt%. A writing instrument comprising the aqueous ink composition for a writing plate according to claim 1 or 2.