JP6701036B2 - Aqueous ink composition for writing board - Google Patents

Description

  The present invention relates to an aqueous ink composition for a writing board suitable for a writing board that is a non-absorbing surface such as a whiteboard or a blackboard.

A water-based ink composition for a writing board used for a writing board such as a whiteboard or a blackboard is designed so that it can be easily wiped off with a soft dry cloth or paper when writing on a non-absorbing surface.
In recent years, writing boards such as whiteboards and blackboards are also expected to be used outdoors as signboards in stores. In this case, it is necessary to maintain erasability even under severer conditions than the indoor environment, that is, even after use for a long time at high temperature and ultraviolet light.

  Conventionally, as a water-based ink composition for a writing board suitable for a writing board used indoors and outdoors, for example, 1) it can be written on a non-permeable writing surface, and the handwriting can be a wet cloth, a wet tissue, a wet color. As a water-based ink for writing boards, which can be easily erased with a damp cloth such as a blackboard wipe and does not disappear even if it gets wet in the rain when used outdoors, pigments, extender pigments, acrylic resins, polyvinyl alcohol or A water-based ink for a writing board, which contains at least a water-soluble cellulose derivative, a polyethylene glycol having a molecular weight of 600 to 6,000 and paste or solid at room temperature, an aliphatic carboxylic acid ester, and water (for example, Patent Document 1). 1) 2) A water-based pigment ink composition for a writing board, etc., which is excellent in water-proof sticking property and good in wiping erasability, and is used as a hiding pigment, a styrene acrylic resin and/or a styrene maleic acid resin, and trehalose. /Pentaerythritol/reduced starch saccharified product, a surfactant containing fluorine, and an aqueous pigment ink composition containing water (for example, refer to Patent Documents 2 to 4 by the applicant). Has been.

However, in the above-mentioned Patent Document 1, the water resistance is the main, and this water resistance test is also to check the presence or absence of peeling of the drawn line when sprayed 10 times with a mist blower, and it can withstand very much in the case of normal rainfall. Moreover, the erasability after exposure to high temperature and ultraviolet rays for a long time is not disclosed at all.
Further, the above-mentioned Patent Documents 2 to 4 are water-based pigment ink compositions suitable for writing boards and the like, which are excellent in water-resistant sticking property and also have good wiping erasability, but exposed to high temperature/ultraviolet rays for a long time. It does not disclose the erasability afterwards.
Furthermore, even if the aqueous ink compositions for writing plates of the above Patent Documents 1 to 4 are used under conditions severer than the indoor environment (after being exposed to high temperature and ultraviolet rays for a long time), sufficient performance is satisfied. It wasn't. This tendency was particularly remarkable when a flat plate pigment typified by an aluminum pigment and a pearl pigment was used.

  On the other hand, Patent Document 5 discloses an erasable ink composition for a marking board containing a water-dispersible pigment, silica, a spreading agent, an emulsifier, and water, in which castor oil is added as a spreading agent. Although disclosed, it is different from the present invention in the objects, problems, and technical ideas (configuration and operation and effect) of the invention.

JP-A-2003-313484 (claims, examples, etc.) JP-A-2014-47292 (claims, examples, etc.) JP, 2014-205747, A (claim, examples, etc.) Japanese Patent Laid-Open No. 2015-48437 (Claims, Examples, etc.) Japanese Patent Publication No. 7-507348 (Claims, page 4, lower right column, line 7)

  The present invention is intended to solve these problems in view of the above-mentioned conventional state of the art, and in a water-based ink composition for a writing board used for a whiteboard, a blackboard, etc., a severer condition than an indoor environment and It is intended to provide an aqueous ink composition for a writing plate, which retains its erasability even after being used outdoors, that is, after being exposed to high temperature and ultraviolet rays for a long time, and which does not adversely affect the writing plate. To aim.

  The present inventor, in view of the current state of the art and the like, as a result of diligent studies, the aqueous ink composition for a writing plate, by containing at least a pigment and a specific component, the aqueous ink for a writing plate for the above purpose. The inventors have found that a composition can be obtained, and completed the present invention.

That is, the aqueous ink composition for a writing board of the present invention is characterized by containing at least a pigment and polyoxyethylene hydrogenated castor oil.
The aqueous ink composition for a writing plate preferably further contains a phosphoric acid ester.
Further, it is preferable to contain a saccharide having a mass average molecular weight of 5000 or less.

  According to the present invention, a water-based ink composition for a writing board used for a whiteboard, a blackboard, etc. was used outdoors under severer conditions than an indoor environment, that is, exposed to high temperature/ultraviolet rays for a long time. Provided is an aqueous ink composition for a writing board, which retains its erasability even afterward and does not adversely affect the writing board.

Embodiments of the present invention will be described in detail below.
The aqueous ink composition for a writing plate of the present invention is characterized by containing at least a pigment and a polyoxyethylene hydrogenated castor oil.

  The pigment used in the present invention is used as a coloring material, and is not particularly limited as long as it is a pigment used for a writing board, and examples thereof include azo pigments, condensed azo pigments, phthalocyanine pigments, and anthraquinone pigments. Pigments, perylene pigments, perinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, organic pigments such as isoindolinone pigments, carbon black, dark blue, red iron oxide, inorganic pigments such as titanium oxide, and pearl pigments, At least one selected from aluminum pigments (powder), metal powder pigments such as brass powder, and scale-like or plate-like pigments such as metal-deposited resin pigments (each alone or two or more, the same applies below) can be mentioned.

The pearl pigment, aluminum pigment (powder), metal powder pigment such as brass powder, metal vapor deposition resin pigment, etc. used as the scale-like or plate-like pigment reflects light in handwriting and imparts glitter to the ink composition. be able to.
Pearl pigments that can be used include natural products such as fish scale foil, and synthetic products such as natural mica whose surface is coated with a metal oxide and synthetic mica whose surface is coated with a metal oxide. Generally, the latter is often used because of its availability, safety, and stability. Pearl pigments exhibit various color tones depending on the type of metal oxide coated on the surface of mica and the coating thickness. Examples of commercially available pearl pigments include Iriodin 100 (particle size 10 to 60 μm, silver color), Iriodin 151 (particle size 1 to 110 μm, silver color), Iriodin 153 (particle size 20 to 100 μm, silver color), Iriodin 201 ( Particle size 5 to 25 μm, gold), Iriodin 217 (particle size 10 to 60 μm, red copper color), Iriodin 289 (particle size 10 to 125 μm, blue), Iriodin 504 (particle size 10 to 60 μm, wine red color), Iriodin 530 (Particle diameter 10 to 125 μm, copper color) (above, manufactured by Merck Japan Co.).

Aluminum pigments that can be used include those obtained as a paste of aluminum fine particles on very thin scales by grinding and polishing aluminum pieces with a petroleum solvent such as higher fatty acids and mineral spirits in a ball mill. It is common. Examples of commercially available aluminum powder pigments include 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) (above, Showa Aluminum Powder Co., Ltd.), FD-4070 (average particle size 7 μm), FD-5060 (average particle size 6 μm) (above, Asahi Kasei Corp.), diamond piece (average particle size) 50 μm, manufactured by Diamond Industry Co., Ltd.).
The metal vapor-deposited resin pigment that can be used is, for example, vacuum-depositing a metal such as aluminum on one surface of a resin film such as a polyester film, and then, when obtaining a desired color, apply colored coating on both surfaces and then cut it into fine pieces. It can be obtained at. Examples of commercially available metal vapor deposition resin pigments include, for example, Crystal Color X-20 (average particle diameter 100 μm, manufactured by Diamond Industry Co., Ltd.) composed of aluminum-coated polyester film, and ERJ NEO#100 (average by Oki Industry Co., Ltd.). 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.
The above various pigments, including these scale-like or plate-like pigments, can be used alone or in combination of two or more, depending on the desired hue and light brightness.

The total content of the pigments including these scale-like or plate-like pigments is in the range of 1 to 20% by mass (hereinafter, simply referred to as “%”), preferably 3 to 15% with respect to the total amount of the ink composition. It is desirable to use.
If the content is less than 1%, the sense of brightness of the drawn line is insufficient, while if it exceeds 20%, the ink outflow becomes insufficient.
When a scale-shaped or plate-shaped pigment is used as the pigment, its size and its average particle diameter are preferably 30 μm or less. When the average particle size of the plate-like particle pigment is 30 μm or less, preferably 20 μm or less, when the ink composition is filled as a writing instrument for a writing plate such as a marking pen, the pigment may block the ink outflow route. Then it will not be impossible to write. The "average particle diameter" in the present invention means an average value measured by the maximum diameter by the image analysis method.

The polyoxyethylene hydrogenated castor oil used in the present invention maintains erasability when a writing board such as a whiteboard or a blackboard is used outdoors, for example, even after being exposed to high temperature/ultraviolet rays for a long time. Moreover, it is a component that does not adversely affect the writing board.
The polyoxyethylene hydrogenated castor oil used preferably has a polyoxyethylene (POE) content of about 10 to 200 mol from the viewpoint of solubility in ink. The polyoxyethylene hydrogenated castor oil also includes hydrogenated (hydrogenated) substances.

Specific examples include the NIKKOL HCO series manufactured by Nikko Chemicals, the Emanon CH series manufactured by Kao, and the Blaunon CW series manufactured by Aoki Yushi Kogyo. In addition, below, the numerical value in the parenthesis written together with polyoxyethylene (POE) shows the number of POE contained in a molecule.
As an example of the polyoxyethylene hydrogenated castor oil, NIKKOL HCO-5 (polyoxyethylene (5) hydrogenated castor oil), NIKKOL HCO-10 (polyoxyethylene (10) hydrogenated castor oil), NIKKOL HCO-20 (polyoxyethylene). Oxyethylene (20) hydrogenated castor oil), NIKKOL HCO-30 (polyoxyethylene (30) hydrogenated castor oil), NIKKOL HCO-40 (polyoxyethylene (40) hydrogenated castor oil), NIKKOL HCO-50 (polyoxyethylene (50)) Hydrogenated castor oil), NIKKOL HCO-60 (polyoxyethylene (60) hydrogenated castor oil), NIKKOL HCO-80 (polyoxyethylene (80) hydrogenated castor oil), NIKKOL HCO-100 (polyoxyethylene (100) hydrogenated castor oil) or more sunlight Chemicals Co., Braunon RCW-20 (polyoxyethylene (20) hardened castor oil), Braunon RCW-40 (polyoxyethylene (40) hardened castor oil), Braunon RCW-50 (polyoxyethylene (50) hardened castor oil), Braunon RCW-60 (polyoxyethylene (60) hardened castor oil), Blaunon RCW-80 (polyoxyethylene (80) hardened castor oil), Blaunon RCW-100 (polyoxyethylene (100) hardened castor oil) or more, manufactured by Aoki Yushi Kogyo Co., Ltd. , Emanone CH-25 (polyoxyethylene (25) hydrogenated castor oil), Emanone CH-40 (polyoxyethylene (40) hydrogenated castor oil), Emanone CH-60 (K) (polyoxyethylene (60) hydrogenated castor oil) or more Kao Co., Ltd., Uniox HC-20 (polyoxyethylene (20) hardened castor oil), Uniox HC-40 (polyoxyethylene (40) hardened castor oil), Uniox HC-60 (polyoxyethylene (60) hardened) Castor oil), UNIOX HC-100 (polyoxyethylene (100) hardened castor oil) and above, manufactured by NOF CORPORATION, and the like.

  The content of these polyoxyethylene hydrogenated castor oils is preferably 0.05 to 5%, more preferably 0.1 to 3% with respect to the total amount of the ink composition. If the content is less than 0.05% with respect to the total amount of the ink composition, the effect of the present invention cannot be exhibited, while if it exceeds 5%, the stability of the ink over time cannot be maintained.

In the present invention, it is preferable to use a phosphoric acid ester in order to further improve the erasability after ultraviolet (UV) irradiation outdoors. In particular, the phosphoric acid esters described below contribute to the improvement of the erasability of the drawn line after UV irradiation.
As the phosphoric acid ester that can be used, for example, an alkyl phosphoric acid ester that is an ester of an aliphatic alcohol and phosphoric acid, an alkyl ether phosphoric acid ester that is an ester of an alkylene oxide adduct of an aliphatic alcohol and phosphoric acid, Examples thereof include the use of alkyl phenyl ether phosphoric acid ester, which is an ester of alkylene oxide adduct of aromatic alcohol and phosphoric acid, or a derivative thereof. These phosphoric acid esters may be used alone or in combination of two or more kinds. May be. Preferable examples include the use of phosphoric acid monoesters of polyoxyethylene alkyl ethers or polyoxyethylene alkylaryl ethers, phosphoric acid diesters of polyoxyethylene alkyl ethers or polyoxyethylene alkylaryl ethers, phosphoric acid triesters, or derivatives thereof. Be done.
In the present invention, a particularly remarkable effect can be obtained particularly when a phosphoric acid ester having a good HLB value of 6 to 20 can be dissolved in ink.
The “HLB value” in the present invention can be determined by the Kawakami method [HLB value=7+11.7 log (MW/MO), MW: molecular weight of hydrophilic portion, MO: molecular weight of lipophilic portion].

Specific examples of the phosphoric acid ester that can be used include phosphanol series manufactured by Toho Chemical Industry Co., Ltd., and Plysurf series manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.
The phosphanol series includes phosphanol ML-220, RB-410, RD-510Y, RD-720N, RL-210, RL-310, RS-410, RS-610, and RS-610. RS-710 (above, manufactured by Toho Chemical Industry Co., Ltd.), Nikko Chemicals Co., Ltd., NIKKOL DLP-10, DOP-8N, DDP-2, DDP-4, DDP-6, DDP-8, DDP-10, etc. Is mentioned.
Among the Plysurf series, Prysurf AL (polyoxyethylene styrenated phenyl ether phosphate, HLB value: 5.6) and A208B [polyoxyethylene (2) lauryl ether phosphate, HLB value: 6. 6], A208F [polyoxyethylene (3) alkyl (C8) ether phosphate, HLB value: 8.7], A212C [polyoxyethylene (6) tridecyl ether phosphate, HLB value: 9. 4], A215C [polyoxyethylene (10) tridecyl ether phosphate, HLB value: 11.5], A219B [polyoxyethylene (20) lauryl ether phosphate, HLB value: 16.2], etc. Is mentioned. These can be used as they are or as a salt neutralized with an alkali metal or an organic base. Also, two or more kinds may be used in combination.

The content of these phosphoric acid esters is 0.05 to 3%, preferably 0.1 to 1% with respect to the total amount of the aqueous ink composition used.
If this content is less than 0.05% with respect to the total amount of the ink composition, sufficient erasability cannot be obtained, while if it exceeds 3%, bleeding of the drawn line is likely to occur.

In the present invention, it is preferable to use a saccharide having a mass average molecular weight of 5000 or less in order to further improve the erasability after ultraviolet (UV) irradiation outdoors. The saccharides having this characteristic give the same effect as the phosphoric acid ester, and the erasability is further enhanced by the combined use (synergistic effect) with the phosphoric acid ester rather than by themselves.
Examples of saccharides having a mass average molecular weight of 5000 or less that can be used include monosaccharides, disaccharides, oligosaccharides, reducing sugars, non-reducing compounds, sugar alcohols, reduced starch degradation products, and mixtures thereof. Of these, non-reducing sugars, particularly sugar alcohols, are preferred. Reducing saccharides may cause discoloration over time or cause pH fluctuations. When a saccharide having a mass average molecular weight of more than 5000, for example, a thickening polysaccharide such as xanthan gum is used, the thickening action may impair the rheological properties, which is not preferable.

The non-reducing saccharide that can be used is not particularly limited as long as it is a saccharide that does not exhibit reducing properties, and examples thereof include sucrose, trehalose, sugar alcohol, and the like, which are saccharides having a mass average molecular weight of 5000 or less. It is a thing.
Glucose (glucose) and other reducing sugars are saccharides that show weak reduction by having a carbonyl group (reducing group) such as an aldehyde group and a ketone group in the molecule, whereas the non-reducing sugars used in the present invention Reducing sugars do not exhibit reducing properties because the reducing groups of monosaccharides are linked to other sugars by glycosidic bonds and the like.

The sugar alcohol that can be used is a general term for chain polyhydric alcohols obtained by reducing (hydrogenating) the carbonyl group of sugars. Examples of sugar alcohols that can be used include "sorbitol" obtained by reducing glucose, "maltitol" obtained by reducing maltose, and reduced starch decomposition obtained by reducing starch syrup or dextrin having different degrees of saccharification. (Reduced starch syrup), reduced dextrin, erythritol, pentaerythritol and the like, and commercially available products can be used.
Among these non-reducing sugars, it is desirable to use at least one selected from sorbitol, erythritol, pentaerythritol, trehalose, and reduced starch decomposition products from the viewpoint of further stability over time.

The content of these saccharides having a mass average molecular weight of 5,000 or less is 0.001 to 30%, preferably 0.01 to 10% with respect to the total amount of the ink composition.
When the content is 0.001% or more, the effect of the present invention can be further exhibited, while when it is 30% or less, the dryness of the drawn line is not deteriorated.

The aqueous ink composition for a writing plate 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 adjusting agent, a surfactant, an antibacterial agent, an antifoaming agent and the like may be appropriately contained within a range that does not impair the effects of the present invention.
A resin dispersant such as a styrene-acrylic copolymer can be used as the pigment dispersant, and a pH of 6.5 to 6.5 is used as the pH adjuster from the viewpoint of stability of ink performance such as pigment dispersion stability. It is preferably set to 10.5, and ammonia, aminomethyl propanol, triethanolamine or the like can be used. Further, as the surfactant, various general-purpose surfactants can be used for the water-based ink composition for a writing board. For example, a surfactant containing fluorine (perfluoroalkenyl ethylene oxide adduct, perfluoroalkyl group addition). And those containing high molecular weight polymers such as perfluorobutane sulfonic acid group addition products).

The production of the aqueous ink composition for a writing plate of the present invention is carried out by mixing and pulverizing the above-mentioned components with a known disperser having a content in each of the above ranges, for example, a ball mill, a roll mill, a sand mill, a flow mill, a dyno mill, or an attritor. To do. The intermediate product obtained by stirring and mixing or mixing and pulverizing these is easily filtered to remove coarse particles and dust by a method such as centrifugal sedimentation to obtain an intended aqueous ink composition for a writing plate. Be done.
Further, the aqueous ink composition for a writing plate of the present invention can be suitably used for a writing plate which is a non-absorbing surface such as a whiteboard marker or a blackboard marker.

  In the water-based ink composition for a writing plate of the present invention configured as described above, by containing at least a pigment and a polyoxyethylene hydrogenated castor oil, conditions more severe than an indoor environment, that is, long-time high temperature/ultraviolet exposure Even after use, the erasability is maintained and the writing plate is not adversely affected.

  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 10 and Comparative Examples 1 to 5]
The water-based ink composition for each writing plate was prepared by mixing and dispersing with a homomixer or a disper according to the formulation shown in Tables 1 and 2 below.
With respect to the obtained water-based ink compositions for writing plates of Examples 1 to 10 and Comparative Examples 1 to 5, the following test methods were used to test the initial water wiping erasability, the water wiping erasability after ultraviolet irradiation, and the high temperature storage after storage. The wiping erasability was evaluated.
The results are shown in Tables 1 and 2 below.

〔Test method〕
(1) Initial water wiping erasability A pen body of PC-5M manufactured by Mitsubishi Pencil Co., Ltd. is filled with a water-based ink composition for each writing board, and a helix having a diameter of about 30 mm is formed under an environment of a temperature of 25° C. and a humidity of 65%. Five pieces were drawn on a black board or a white board, and about 25 g of tap water was added to a Kim towel (laboratory paper towel, manufactured by Nippon Paper Crecia Co., Ltd.), and the board was rubbed once while keeping the board horizontal. The appearance of the drawn line after rubbing was observed and evaluated according to the following evaluation criteria (n=5).
Evaluation criteria:
⊚: It was possible to erase by applying a horizontal force without placing a weight.
◯: A force of more than 0 N to 7.84 N (weight 0.8 kg) or less was applied from above to rub and erase.
Δ: A force of more than 7.84 N to 9.8 N (weight 1 kg) or less was applied from above to scrape and erase.
▲: A force of more than 9.8 N and less than 19.6 N (weight 2 kg) was applied from above to scrape and erase.
Poor: Even if a force of 19.6 N (weight 2 kg) was applied from above, it could not be erased.

(2) Water wiping erasability after irradiation with ultraviolet rays The pen body of PC-5M manufactured by Mitsubishi Pencil Co., Ltd. is filled with the water-based ink composition for each writing board, and the diameter of about 30 mm is obtained under the environment of the temperature of 25° C. and the humidity of 65%. Draw 5 spirals on a black board or white board, and irradiate with a xenon fade meter X25F (FLR40SW/M/36, Suga Test Instruments Co., Ltd.) for 200 hours according to JIS S 6037-2006, and then Kim towel (experiment) About 25 g of tap water was added to a paper towel for paper, manufactured by Nippon Paper Crecia Co., Ltd., and the board was rubbed once while keeping the board horizontal. The appearance of the drawn line after rubbing was observed and evaluated according to the above-mentioned initial evaluation standard for water wiping erasability (n=5).

(3) Water wiping erasability after storage at high temperature The pen body of PC-5M manufactured by Mitsubishi Pencil Co., Ltd. is filled with the water-based ink composition for each writing board, and the width is fivefold in an environment of a temperature of 25° C. and a humidity of 65%. Draw a 15 mm spiral 8 times on a black board or white board, store it in an environment of 80°C for 1 week, take it out, and return it to room temperature to a Kim towel (laboratory paper towel, manufactured by Nippon Paper Crecia Co., Ltd.) 25 g of tap water was added, and the board was rubbed once while keeping it horizontal. The appearance of the drawn line after rubbing was observed and evaluated according to the above-mentioned initial evaluation standard for water wiping erasability (n=5).

  As is clear from the results of Tables 1 and 2 above, Examples 1 to 10 of the present invention were compared with Comparative Examples 1 to 5 which were outside the scope of the present invention. It was confirmed that the water-based ink composition for a writing plate is capable of maintaining a high level of water-erasability and water-erasability after storage at high temperatures. Further, the aqueous ink compositions for writing plates of Examples 1 to 10 were visually observed after the wiping and erasing after the ultraviolet irradiation and after the wiping and erasing after the high temperature storage. It was also confirmed that the drawn lines on the surface were erased cleanly and that it did not adversely affect the writing board.

  An aqueous ink composition for a writing board suitable for a whiteboard marker or a blackboard marker is obtained.

Claims (3)

An aqueous ink composition for a writing plate, which contains at least a pigment and 0.05 to 5 mass% of polyoxyethylene hydrogenated castor oil.   The aqueous ink composition for a writing plate according to claim 1, further comprising a phosphoric acid ester.   Furthermore, the water-based ink composition for a writing plate according to claim 1 or 2, further comprising a saccharide having a mass average molecular weight of 5000 or less.