JP7145085B2 - Aqueous ink composition for writing board - Google Patents

Description

TECHNICAL FIELD The present invention relates to a water-based ink composition for writing boards used for writing boards that are non-absorbing surfaces such as whiteboards and blackboards, and more specifically, it has adhesiveness that can withstand outdoor environments such as rainwater, and is contrary to this. The present invention relates to a water-based ink composition for a writing board that can be erased by wiping with water with a light force.

Aqueous ink compositions for writing boards used for writing boards such as whiteboards and blackboards are designed so that writing on a non-absorbent surface can be easily wiped off with a soft dry cloth or paper.
In recent years, writing boards such as whiteboards and blackboards are expected to be used outdoors as store signboards and the like.

Conventionally, as a water-based ink composition for a writing board suitable for indoor and outdoor use, the applicant of the present application has proposed 1) at least a concealing pigment, a styrene acrylic acid resin and/or a styrene maleic acid resin, and trehalose. , a water-based pigment ink composition characterized by containing a fluorine-containing surfactant and water (see, for example, Patent Document 1); An aqueous pigment ink composition characterized by containing a maleic acid resin, pentaerythritol, a fluorine-containing surfactant, and water (see, for example, Patent Document 2); 3) at least a concealing pigment; An aqueous pigment ink composition characterized by containing a styrene acrylic acid resin and/or a styrene maleic acid resin, a reduced starch saccharate, a fluorine-containing surfactant, and water (see, for example, Patent Document 3). etc.

However, the above Patent Documents 1 to 3 have unprecedented adhesion and excellent erasability by wiping with water, but also have adhesion that can withstand outdoor environments such as rainwater, and are contrary to this. At present, there is a demand for a water-based ink composition for writing boards that can be erased by wiping with water with a light force.

Japanese Patent Application Laid-Open No. 2014-47292 (Claims, Examples, etc.) JP 2014-205747 A (Claims, Examples, etc.) Japanese Patent Application Laid-Open No. 2015-48437 (Claims, Examples, etc.)

The present invention is intended to solve this problem in view of the above-described conventional status quo, and the water-based ink composition for writing boards used for whiteboards, blackboards, etc. is subjected to harsher conditions than the indoor environment. To provide a water-based ink composition for a writing board, which has adhesiveness that can withstand outdoor use, that is, in outdoor environments such as rainwater, and can be erased with a light force by wiping with water, which contradicts this. aim.

The inventors of the present invention have made intensive studies in view of the above-mentioned conventional state of the art, and as a result, found that the aqueous ink composition for a writing board having the above-described objective can be obtained by containing at least a pigment and a specific compound. , have completed the present invention.

That is, the water-based ink composition for a writing board of the present invention is characterized by containing at least a pigment and at least one or more compounds selected from trimethylglycine and/or carnitines.
The content of at least one or more compounds selected from trimethylglycine and/or carnitines is preferably 0.5 to 10% by mass relative to the total amount of the ink composition.

According to the present invention, a water-based ink composition for a writing board is provided that has adhesiveness that can withstand outdoor environments such as rainwater and that can be erased by wiping with a damp cloth with a light force.

Embodiments of the present invention will be described in detail below.
The aqueous ink composition for a writing board of the present invention is characterized by containing at least a pigment and at least one or more compounds selected from trimethylglycine and/or carnitines.

The pigment used in the present invention is not particularly limited as long as it is a pigment used for writing boards.
Specifically, carbon black, ultramarine blue, inorganic pigments such as titanium dioxide pigments, azo pigments, phthalocyanine pigments, indigo pigments, thioindigo pigments, threne pigments, quinacridone pigments, anthraquinone pigments, threne pigments, diketopyrrolo Organic pigments such as pyrrole-based pigments, dioxazine-based pigments, perylene-based pigments, perinone-based pigments, and isoindolinone-based pigments, aluminum pigments, metal-deposited resin pigments in which a metal-deposited film of aluminum or the like is formed on a transparent or colored transparent film, pearls Pigments and the like can be mentioned, and at least one of them (each alone or two or more, the same shall apply hereinafter) can be mentioned.

Preferably, at least one selected from pearl pigments, aluminum pigments (powder), metal powder pigments such as brass powder, and plate-like (flake-like) pigments such as metal vapor-deposited resin pigments is desirable.
Pearl pigments, aluminum pigments (powder), metal powder pigments such as brass powder, and metal-deposited resin pigments used as these plate-like pigments can reflect light in handwriting and impart luster to the ink composition. can.
Pearl pigments that can be used include natural products such as fish scale foil, synthetic products such as natural mica coated with a metal oxide, and synthetic mica coated with a metal oxide. In general, the latter is often used due to its availability, safety, and stability. Pearl pigments exhibit various color tones depending on the type of metal oxide coated on the mica surface and the thickness of the coating. Commercially available pearl pigments include, for example, Iriodin 100 (particle size 10 to 60 μm, silver), Iriodin 151 (particle size 1 to 110 μm, silver), Iriodin 153 (particle size 20 to 100 μm, silver), Iriodin 201 ( Particle size 5-25 μm, gold), Iriodin 217 (particle size 10-60 μm, red copper color), Iriodin 289 (particle size 10-125 μm, blue), Iriodin 504 (particle size 10-60 μm, wine red), Iriodin 530 (Particle diameter 10 to 125 μm, copper color) (manufactured by Merck Japan Ltd.).

Aluminum pigments that can be used are those obtained as a paste of aluminum fine particles on very thin scales by pulverizing and polishing aluminum flakes with a petroleum solvent such as higher fatty acid or mineral spirits in a ball mill. Common. Commercially available aluminum powder pigments include, for example, Friend Color F-700 series (average particle size 11 μm), F-500 series (average particle size 17 μm), F-350 series (average particle size 30 μm), F-100 Series (average particle size 74 μm) (manufactured by Showa Aluminum Powder Co., Ltd.), FD-4070 (average particle size 7 μm), FD-5060 (average particle size 6 μm) (manufactured by Asahi Kasei), diamond piece (average particle size 50 μm, manufactured by Dia Kogyo Co., Ltd.).
The metal vapor-deposited resin pigment that can be used is, for example, by vacuum-depositing a metal such as aluminum on one side of a resin film such as a polyester film, and then finely cutting the film after applying a color coating on both sides to obtain a desired color. is obtained by Commercially available metallized resin pigments include, for example, Crystal Color X-20 (average particle size 100 μm, manufactured by Dia Kogyo Co., Ltd.) composed of an aluminum-coated polyester film, Elgy NEO #100 manufactured by Oike Kogyo Co., Ltd. (average particle size 110-120 μm), #150 (average particle size 90-100 μm), #200 (average particle size 55-65 μm), #325 (average particle size 30-40 μm), #500 (average particle size 10-20 μm) etc.

Further, it is desirable that the size of these plate-like pigments and the average particle diameter be 30 μm or less. If the average particle size of the flat pigment is 30 μm or less, preferably 20 μm or less, when the ink composition is filled as a writing instrument for a writing board such as a marking pen, the pigment will block the ink outflow path. It will not become impossible to write.
The average particle size of the plate-like pigments defined in the present invention (including Examples, etc.) was measured using a particle size distribution analyzer HRA9320-X100 (manufactured by Nikkiso Co., Ltd.) with a refractive index of 1.81 on a volume basis. Means the calculated D50 value.

The content of these pigments is desirably in the range of 1 to 40% by mass (hereinafter simply referred to as "%"), preferably 3 to 30%, based on the total amount of the ink composition.
If the content of these pigments is less than 1%, the brightness of drawn lines is insufficient.

At least one or more compounds selected from glycine betaine [also known as trimethylglycine, (CH ₃ ) ₂ N ⁺ (CH ₃ )CH ₂ COO ^- ] and/or carnitines used in the present invention are used as an erasability imparting component and the like. Even if it is contained in the water-based ink composition for writing boards, it does not cause deterioration of ink performance, etc., and exhibits adhesion that can withstand outdoor environments such as rainwater, and is incompatible with this, and can be erased by wiping with water. can be realized with a light force, and the effects of the present invention can be effectively exhibited.

Carnitine used in the present invention is an amino acid derivative that is biosynthesized from the amino acids lysine and methionine, has a quaternary ammonium in its direct molecular structure, and has a betaine structure.
Examples of carnitines that can be used include L-carnitine, D-carnitine, and DL-carnitine, which are basic skeletons (these three components are referred to as "L(D)-carnitine"), their salts, and their and salts of the above derivatives, and at least one of these can be used.

Specific examples of L(D)-carnitine salts include alkali metal salts such as carnitine chloride, alkaline earth metal salts such as magnesium salts, mineral salts such as hydrochlorides, tartrates, citrates, and succinates. , and organic acid salts such as fumarate.
Specific examples of derivatives of L(D)-carnitine include acetylcarnitine, palmitoylcarnitine, lauroylcarnitine and the like.
Specific examples of salts of carnitine derivatives include glycine propionylcarnitine hydrochloride, acetylcarnitine dihydrochloride, taurine acetylcarnitine hydrochloride and the like.
Among these, L-carnitine, DL-carnitine hydrochloride, and acetyl L-carnitine are preferably used in terms of safety, availability, and excellent stability over time in the ink composition for writing boards. .

The content of at least one or more compounds selected from these glycine betaine and/or carnitines is preferably 0.5 to 10%, more preferably 1 to 5%, relative to the total amount of the ink composition. It is desirable to
If the content is less than 0.5%, the effect of the present invention cannot be exhibited, while if it exceeds 10%, the effect of the present invention does not change so much, but rather the writing performance due to the increase in viscosity. This will result in a decrease in the image quality, blurring of drawn lines, and the like.

The water-based ink composition for a writing board of the present invention contains at least one or more compounds selected from the above pigments, trimethylglycine and/or carnitines, as well as resin particles, saccharides, etc., to the extent that the effects of the present invention are not impaired. can be used.
Resin particles that can be used include hollow particles. The hollow particles used suppress the generation of adverse effects on the writing board when a flat pigment is used as the pigment, suppress the formation of a hard cake due to the flat pigment, and become a component that imparts an improvement in erasability. is.
The hollow particles to be used should be rather small in order to exhibit the desired effects such as suppressing the occurrence of adverse effects on the writing board, suppressing the formation of hard cakes, and improving erasability without impairing the luster of the flat pigment. The particle size is advantageous, and the average particle size (D50) is preferably 0.1 to 2.0 μm, preferably 0.1 to 1.0 μm, more preferably less than 0.6 μm. . If the average particle size exceeds 2.0 μm, when a plate-like pigment is used as the pigment, the feeling of brilliance is impaired, which is not preferable.

In addition, the hollow particles to be used are organic particles such as resin particles and inorganic particles such as silica having a hollow part, and suppress the occurrence of adverse effects on the writing board without impairing the luster of the flat pigment. The material and shape are not particularly limited as long as the desired effects such as suppression of hard cake formation and improvement of erasability can be exhibited. Hollow particles or multi-hollow particles having a plurality of hollows per hollow particle may be used.
For example, the hollow particles to be used include inorganic hollow particles such as glass and silica particles, styrene resins such as crosslinked styrene-acrylic resins, acrylic resins such as acrylonitrile-acrylic resins, and methacrylic resins. Hollow resin particles such as resins, phenolic resins, fluorine-based resins, polyamide-based resins, polyimide-based resins, polycarbonate-based resins, and polyether-based resins can be used. Preferably, the material is styrene or acrylic resin, and the shape is spherical. The effect of the present invention cannot be exhibited with particles having no hollow portion, that is, so-called solid particles (solid particles).

Specific hollow particles that can be used include, for hollow resin particles, commercially available Nipol MH5055 manufactured by Nippon Zeon Co., Ltd.; Sunsphere, UitraE, OP-84J, SN-1055 manufactured by Rohm and Haas; SX866 (A), etc. of Examples of inorganic silica hollow particles include Silinax manufactured by Nittetsu Mining Co., Ltd. The hollow particles to be used can be used singly (one kind) or in combination of two or more kinds.
The content of these resin particles is preferably 0.1 to 10%, more preferably 0.5 to 8% in terms of solid concentration, relative to the total amount of the ink composition.

In the present invention, it is preferable to use sugars in order to further improve erasability after ultraviolet (UV) irradiation outdoors.
As sugars that can be used, it is desirable to use sugars having a mass average molecular weight of 5,000 or less. The saccharides with this characteristic further enhance the erasability.
Usable sugars having a mass average molecular weight of 5000 or less include monosaccharides, disaccharides, oligosaccharides, reducing sugars, non-reducing sugars, sugar alcohols, hydrogenated starch hydrolysates, and mixtures thereof. It is not preferable to use saccharides having a mass average molecular weight exceeding 5,000, for example, polysaccharide thickeners such as xanthan gum, because their thickening action may impair the rheological properties.

The content of these sugars is desirably 0.001 to 30%, preferably 0.01 to 10%, relative to the total amount of the water-based ink composition for writing boards.
When the content is 0.001% or more, the effects of the present invention can be further exhibited, and on the other hand, when it is 30% or less, the dryness of drawn lines is not lowered.

The water-based ink composition for a writing board of the present invention is prepared with water (purified water, distilled water, ion-exchanged water, pure water, etc.) as the balance in addition to the above components. , a pH adjuster, a surfactant, an antibacterial agent, an antifoaming agent, and other optional ingredients, etc., can be appropriately contained within a range that does not impair the effects of the present invention.
As the pigment dispersant, a resin dispersant such as a styrene-acrylic copolymer can be used, and as the pH adjuster, from the viewpoint of stability of ink performance such as pigment dispersion stability, the pH is adjusted from 6.5 to 6.5. 10.5 is desirable, and ammonia, aminomethylpropanol, triethanolamine, etc. can be used. As the surfactant, various general-purpose surfactants can be used for the aqueous ink composition for writing boards. and those containing high-molecular-weight polymers such as perfluorobutanesulfonic acid group adducts).

The water-based ink composition for a writing board of the present invention is produced by mixing and pulverizing each of the above-described components in a content within each of the above ranges using a known dispersing machine such as a ball mill, roll mill, sand mill, flow mill, dyno mill, or attritor. do The desired water-based ink composition for writing boards can be easily obtained by removing coarse particles and dust from the intermediates obtained by stirring and mixing or mixing and pulverizing them by a method such as filtration or centrifugal sedimentation, if necessary. be done.
In addition, the aqueous ink composition for writing boards of the present invention can be suitably used for writing boards that serve as non-absorbent surfaces such as whiteboard markers and blackboard markers.

The water-based ink composition for a writing board of the present invention configured as described above contains at least a pigment and at least one or more compounds selected from trimethylglycine and/or carnitines, thereby preventing rainwater and other outdoor environments from A water-based ink composition for a writing board suitable for whiteboards, blackboards, etc., which can exhibit unprecedented adhesion that can withstand even squeezing, and can be erased by wiping with water, which contradicts this, with a light force. is obtained.
The action mechanism of the present invention is presumed as follows. That is, as described above, in the drawn line of the water-based ink composition for a writing board containing at least a pigment and containing at least one or more compounds selected from trimethylglycine and/or carnitines, trimethylglycine and/or Since carnitines are solid at room temperature, they impart appropriate hardness and stickiness to drawn lines. Inside the drawn line, the nitrogen atoms of trimethylglycine and/or carnitines are oriented on the writing board surface, and when subjected to an erasing operation, water permeates the interface between the coating film and the writing board surface due to pressure, and trimethylglycine and / Or dissolve carnitines. As a result, the sticking force of the drawn line is lowered, and erasing becomes possible.
As a result, it is possible to exhibit a non-conventional adhesion that can withstand outdoor environments such as rainwater, and to realize erasing by wiping with a damp cloth, which contradicts this, with a light force.

EXAMPLES 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.

[Examples 1 to 9 and Comparative Examples 1 to 3]
Each water-based ink composition for a writing board was prepared by mixing and dispersing using a homomixer or a disper according to the formulations shown in Tables 1 and 2 below.
The obtained water-based ink compositions for writing boards of Examples 1 to 9 and Comparative Examples 1 to 3 were evaluated for erasability by wiping with water and adhesion by the following test methods.
These results are shown in Tables 1 and 2 below.

〔Test method〕
<Erasability by wiping with water>
A PC-5M pen body manufactured by Mitsubishi Pencil Co., Ltd. is filled with each water-based ink composition for writing boards, and five spirals with a diameter of about 30 mm are placed on a black board or white board in an environment of 25 ° C. and a relative humidity of 65%. , and after being stored for one day in an environment of 50 ° C. and a relative humidity of 30%, it was taken out and returned to room temperature. , while keeping the board horizontal, rubbed with a load of 600 gf. The state of drawn lines after rubbing was observed and evaluated according to the following evaluation criteria (n=5).
Evaluation criteria:
A: It could be erased by rubbing once.
B: Erasable by rubbing twice. C: Erasure required rubbing three times or more.

<Adhesion>
A PC-5M pen body manufactured by Mitsubishi Pencil Co., Ltd. is filled with each water-based ink composition for writing boards, and five spirals with a diameter of about 30 mm are placed on a black board or white board in an environment of 25 ° C. and a relative humidity of 65%. , and rubbed once with a Kimtowel (experimental paper towel, manufactured by Nippon Paper Crecia Co., Ltd.) while keeping the board horizontal while applying a load of 400 gf. The state of drawn lines after rubbing was observed and evaluated according to the following evaluation criteria (n=5).
Evaluation criteria:
A: There was no change in drawn lines.
B: A small portion of the drawn line was erased.
C: 1/5 or more of the drawn lines were erased.

As is clear from the results in Tables 1 and 2 above, Examples 1 to 9 of the present invention are highly compatible with wet wiping erasability and adhesion compared to Comparative Examples 1 to 3, which are outside the scope of the present invention. It was found to be a water-based ink composition for a writing board that can be used.

A water-based ink composition for a writing board can be obtained that can be suitably used as a writing instrument for whiteboard markers such as marking pens and felt-tip pens or for blackboard markers.

Claims (2)

An aqueous ink composition for a writing board, comprising at least a pigment and at least one or more compounds selected from trimethylglycine and/or carnitines. 2. The method according to claim 1, wherein the content of at least one compound selected from trimethylglycine and/or carnitines is 0.5 to 10% by mass relative to the total amount of the ink composition. A water-based ink composition for writing boards.