KR100976919B1 - Ink with nano size silica sol dispersed therein for use on a white board - Google Patents

Abstract

The present invention relates to an ink for whiteboard comprising 1 to 10% by weight of silica sol in a size range of 10 to 100 nm, and in the present invention, a silica sol is added to an ink for whiteboard to disperse a pigment and a polymer additive. It is possible to reduce the content of polymer additives such as dispersibility and viscosity regulator by increasing the performance viscosity, thereby reducing the production cost and production time has the advantage of increasing the productivity of the ink.

Silica sol, ink, whiteboard, dispersible

Description

Ink with nano size silica sol dispersed therein for use on a white board}

The present invention relates to a white chalkboard ink in which nano silica sol is dispersed. More specifically, the present invention is a whiteboard ink containing 1 to 10% by weight of silica sol having a particle size of 10 to 100nm, the ink moisturizing, dispersibility, dryness, and durability is improved Relates to ink.

The most important characteristic that a white board ink should have

First, the pigment and the polymer additive should be uniformly dispersed in the form of fine particles (good dispersibility), second, the dispersibility of the fine particles must be maintained for a long time (good dispersibility persistence), and third, the drying speed of the ink must be appropriate ( Proper drying speed), fourth, the ink on the board must be cleared well (excellent erasing), fifth, there is no bleeding or flow of ink on the board, and sixth, the viscosity, usability, and color are consistent even after prolonged use. It must be maintained (good homogeneity). Some of these characteristics are mutually opposite, and as some characteristics increase, others decrease. For example, if the viscosity of the ink is low, the ink can be efficiently filled in the pen, but in actual use, the flowability may appear on the blackboard and separation of the pigment and the solvent may occur after the ink is retained for a long time. In addition, when the viscosity is high, the dispersibility of the pigment is maintained for a long time, there is a disadvantage that the eraseability of the ink on the blackboard is greatly reduced.

The most important properties of the whiteboard ink are the dispersibility of the pigment and the dispersion persistence of the dispersed pigment. If the dispersibility of the pigment is not uniform, the color of the pigment cannot be uniformly developed, the pigment is separated from the solvent, the color of the ink is blurred, the dryness of the solvent is also increased, and the persistence is greatly reduced. The problem arises that the time becomes unusable.

The present inventors have conducted a long-term study to produce ink for whiteboard which is excellent in dispersibility and dispersibility of pigment and can be kept homogeneous in viscosity and color for a long time. Inks that have been commercially available until now have been prepared by dispersing pigments using only polymer and organic additives. In addition, when general inorganic silica is added, inorganic silica is used for the white board alcoholic ink because of the phenomenon that the dispersibility is very low due to the relatively high density of silica and the inorganic silica particles having a larger particle density than the organic additive are easily precipitated after dispersion. No additives were used. However, with the recent development of nanotechnology, the surface modification technology of silica has developed along with the development of nano-sized ultrafine silica.

The present inventors have found that when the nano-sized silica sol is applied to an alcoholic ink for whiteboard, the dispersion and the sustainability of pigments are remarkably improved compared to the case of using only conventional polymers and organic additives. Although the nano-sized silica sol is an inorganic additive, it was confirmed that it is well mixed with the organic component in the ink, and also improves the dispersibility of the pigment.

In general, the manufacturing process of the whiteboard ink includes the steps of 1) stirring a polymer additive such as a pigment, a polymer dispersant, a dispersion stabilizer of the pigment, and a polymer viscosity modifier of a palmitate system, and 2) a moisturizer and a drying regulator of the stirred reaction mixture. It is added to an alcohol solvent to which the additive is added, such as stirring, and 3) the milling step of dispersing the reaction mixture into fine particles.

The milling step, which is a process of uniformly crushing and dispersing the pigment in the ink manufacturing process, is a step of grinding and dispersing by adding zirconia particles having a size of several millimeters. In this process, it is limited to grind and disperse pigments or polymers to several micrometers by using only a few millimeters of zirconia particles. There are disadvantages. In the present invention, by adding a silica sol having a size of 10 to 100nm to the ink composition itself, it is possible to more efficiently and uniformly disperse the pigment and the polymer additive, and the dispersed pigment can be stably maintained at a uniform particle size for a long time. . Therefore, according to the present invention, the addition content of the dispersant is reduced, and the time of the milling step using zirconia can also be shortened, which is economic in process.

On the other hand, the white blackboard is a glossy board of white, due to the phenomenon that a lot of light is reflected by the illumination of the room, there is a disadvantage that the letter itself written on the blackboard is not easily visible by the reflection of light. According to the present invention, however, dozens of nano-sized silica sol is added to the ink to cause diffuse reflection of light, so that the letters written on the blackboard without blind spots are clearly seen from all angles.

An object of the present invention is to add a nano-sized silica sol, which is an inorganic material, in the preparation of the whiteboard ink prepared by adding an organic pigment and an organic dispersant to an alcohol solvent, thereby improving the moisture retention and dispersibility of the ink, durability, paper It is to provide an ink which is greatly improved in dryness and durability.

The present invention relates to an ink composition for whiteboard containing 1 to 10% by weight of silica sol having a size in the range of 10 to 100 nm. In the present specification, an ink for whiteboard is interpreted to mean an ink filled in a whiteboard pen.

The size of the silica sol according to the present invention is used in the range of 10 ~ 100nm, preferably the particle size of the silica sol is in the range of 50 ~ 100nm. If the size of the silica sol is outside the range of 10 ~ 100nm, the pigment does not disperse well, and shows the best dispersibility when the size of the silica sol is 50 ~ 100nm.

The ink composition according to the present invention contains silica sol in the range of 1 to 10% by weight. If the content of the silica sol is less than 1% by weight, the dispersibility of the desired pigment is not obtained. If the content of the silica sol exceeds 10% by weight, the compatibility with the organic component is poor and the eraseability of the ink is reduced. Since the viscosity of the ink may vary depending on the external temperature, the content of the silica sol may vary within this range depending on the preparation time of the ink. In addition, since the dispersibility and viscosity vary depending on the type of pigment, the content of the silica sol may vary within the range according to the type of the pigment. Those skilled in the art can easily determine the appropriate content of the silica sol within the above range in consideration of the time of manufacture of the ink or the kind of pigment.

In the ink composition according to the present invention, other components except for the nano-sized silica sol are additives such as pigments, dispersants, dispersion stabilizers, viscosity regulators, plasticizers, drying retardants, mold release agents, and humectants which are commonly used in ink preparation, Lower alcohol solvents such as ethanol and isopropyl alcohol.

In the ink composition according to the present invention, additives such as pigments, dispersants, dispersion stabilizers, viscosity modifiers, plasticizers, drying retardants, mold release agents and humectants are not particularly limited and are commercially available as ink additives filled in a white chalkboard pen. Which may be selected from conventional ingredients.

In one embodiment of the present invention, the ink composition is 1 to 10% by weight of organic pigment, 1 to 3% by weight of dispersant, 2 to 5% by weight of dispersion stabilizer, 0.1 to 1% by weight of viscosity modifier, 0.1 to 1% by weight of moisturizer, 10 1 to 10 weight percent silica sol in the size range of 100 nm, and 70 to 90 weight percent of ethanol and / or isopropanol solvent.

According to the present invention, the ink components are mixed and stirred with a homomixer, and the mixture of the stirred components is dispersed into fine particles to prepare an ink composition for a white blackboard. The method of preparing the ink composition comprises the steps of mixing, stirring and milling the components conventionally practiced in the art.

The present invention provides an ink composition that can greatly increase the sustainability of use by maintaining a uniform color of the ink by adding an inorganic silica sol to the whiteboard ink prepared using only an organic compound to greatly increase dispersibility and dispersion stability. do. In addition, the white ink for ink according to the present invention includes a nano-sized silica sol to increase the dispersibility of pigments and polymer additives, increase the viscosity to reduce the content of polymer additives such as dispersibility and viscosity modifier, thereby producing The cost and production time can be reduced, which greatly increases productivity.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the following examples are only for illustrating the present invention, and the present invention is not limited to these examples.

Example

In the embodiment, a nano-sized silica sol was added according to the present invention to prepare an ink composition for a white blackboard.

7 g of a pigment selected from an organic black pigment, a blue pigment, a red pigment, or a green pigment, 3 g of a solvent dispersant, 3 g of a palmitate-based polymer resin, 6 g of a 50 nm silica sol, and 45 g of ethanol as a dispersion stabilizer are sufficiently mixed with a homomixer. Stirred. Pigment was dispersed by sufficiently milling the stirred mixed solution using a dynomill with zirconia balls. To a milled dispersion solution, a solution of 0.5 g of a viscosity modifier and 0.5 g of a moisturizer was dissolved in 35 g of a solvent mixture consisting of 20 g of ethanol and 15 g of isopropyl alcohol, and 100 g of ink samples of four colors were prepared by stirring thoroughly with a homomixer. .

The viscosity, specific gravity, and dispersion particle size of the black, blue, red, and green ink samples prepared according to the examples were measured and shown in Table 1. The measurement conditions of each physical property are as follows.

Viscosity: 20 g of the prepared ink sample was placed in a 20 ml beaker, and the temperature was adjusted to 25 ° C., followed by a SPOOKLE No. Viscosity was measured after reading the scale after rotating for 2 minutes at 60 rpm using BL.

Specific gravity: measured using a hydrometer at 25 ° C.

Dispersion particle size: measured using a MASTERSIZER 2000 from Malvern.

TABLE 1

Properties black blue Red green Viscosity (cps) 9.0 8.4 10.9 5.5 importance 0.846 0.848 0.846 0.838 Dispersion particle size (μm) 0.202 0.213 0.220 0.209

Comparative example

An ink control sample for a white blackboard was prepared in the same manner and composition as in Example except that no nano-sized silica sol was added.

The viscosity, specific gravity, and dispersion particle size of the black, blue, red, and green ink control samples prepared according to the comparative example were measured and shown in Table 2 in the same manner as in Example.

TABLE 2

Properties black blue Red green Viscosity (cps) 9.1 8.3 11.0 5.7 importance 0.838 0.841 0.838 0.831 Dispersion particle size (μm) 0.235 0.240 0.245 0.230

As shown in Table 1, in the case of the ink composition to which silica sol is added, the dispersion particle size is low, so that effective dispersion is achieved, and thus the amount of dispersant and dispersion stabilizer can be reduced, whereas the viscosity and specific gravity are almost the same as those of not adding silica sol. Inks having the same value could be produced.

The black and blue ink samples obtained in the examples and the comparative examples were filled in a pen for white blackboard, and these pens were left up and down, respectively, and left for 72 hours. After 72 hours, each pen was filled with a pen filled with ink samples, and the sharpness of the drawn line was visually observed. The results are shown in FIGS. 1 to 4. The pen filled with the ink sample of the silica sol-added example showed very clear lines even when used for a long time (FIG. 1 and FIG. 3). However, the pen filled with the ink control sample of the comparative example without the silica sol was added. In the case of relatively cloudy and smeared lines appeared (Fig. 2 and 4). Therefore, it can be seen that the addition of silica sol increases the dispersibility of the pigment and improves the dispersion stability.

FIG. 1 is a photograph taken on a white blackboard after standing for 72 hours with a white blackboard pen filled with a black and blue ink sample obtained in an example upright.

Figure 2 is a photograph taken on a white blackboard after leaving the white blackboard pen filled with the black and blue ink control samples obtained in the comparative example left for 72 hours.

3 is a photograph taken on a white blackboard after standing for 72 hours with a white blackboard pen filled with the black and blue ink samples obtained in the example down.

FIG. 4 is a photograph taken on a white blackboard after standing for 72 hours with a white blackboard pen filled with black and blue ink samples obtained in a comparative example down.

Claims (2)

1-10% by weight of organic pigment, 1-3% by weight of dispersant, 2-5% by weight of dispersion stabilizer, 0.1-1% by weight of viscosity modifier, 0.1-1% by weight of moisturizer, 1-10% by weight of silica sol in size range of 10-100 nm %, And 70 to 90% by weight of a solvent selected from ethanol, isopropyl alcohol, or mixtures thereof. delete

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