JPH06128522A - Marking ink composition for writing board - Google Patents

Abstract

PURPOSE:To obtain a marking ink compsn. for a writing board which compsn. is excellent in pigment storage stability, particularlly little in a decrease in concn. even when stored in a marking penholder set upward, and excellent in erasability not only at the initial stage but also after the lapse of time. CONSTITUTION:A polyvinyl butyral resin and a pigment are used in combination with a lower aliph. alcohol, a fatty acid ester, and particularly a polyoxyethylene-polyoxypropylene-castor oil in the form of a block polymer added thereto as a surfactant additive to prepare a marking ink for a writing board.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a marking ink for a writing board, and in particular, it can be written on an impermeable writing surface, that is, a polypropylene plate, a melamine baking coating plate, an enamel plate, a fluororesin film or the like. The present invention also relates to a marking ink composition that can be easily erased by lightly rubbing the handwriting with a dry cloth or a flexible paper as needed.

[0002]

2. Description of the Related Art Hitherto, writing inks for writing boards have been prepared by various methods by adding various surfactants, fatty acid esters and the like as additives to a marking ink composition comprising a resin, a pigment and a solvent.

[0003]

In the marking ink for writing boards, a pigment is generally used as a coloring agent. For this reason, when the writing pen for writing plates is stored in an upward or downward direction, the pigment is likely to settle down. When stored upward, the color of the handwriting becomes lighter, and when stored downward, the color of the handwriting becomes darker. If the ink is stored face-down, if unmilled coarse-grained pigment is present in the ink or the pigment dispersion stability is poor, the felt core will be clogged, resulting in poor writing. Therefore, a note is written on the writing-pen marking pen so that the user always saves it horizontally after using the writing-pen marking pen. However, if it is used in general, it may be erroneously stored in a writing brush. Further, even if it cannot be stored upward, the color tends to be faint even if it is stored a little diagonally upward.

In recent years, in order to solve this problem, liquid resin-processed pigments have been used in addition to conventional chip-shaped resin-processed pigments as resin-processed pigments having good pigment dispersion stability. Since the coarse particles have been cut after the treatment, a liquid resin-processed pigment that is less likely to cause clogging even when it is made into an ink using a liquid-processed pigment and stored downward is obtained. However, as a surfactant for additives, there is also a problem with compatibility with the dispersant used in liquid resin-processed pigments, and those with poor compatibility do not clog when stored downward. Even if it does not occur, there is a drawback that the color of the handwriting tends to become pale in a short period of time when stored upward.

[0005]

In view of the above-mentioned problems, the present invention does not impair the dispersion stability of various resin-processed pigments when an ink composition is used as one of the surfactants of the additive, and It is a surfactant that is compatible with the dispersant used in the processed pigments, and when used in combination with fatty acid esters as an additive for the marking ink for writing boards, it has the erasability of the handwriting or erasability with time. Various investigations were made on the unaltered surfactants. As a result, by using a block polymer polyoxyethylene polyoxypropylene castor oil, which is compatible with various resin-processed pigments, as a surfactant, it was made into an ink with various resin-processed pigments and fatty acid esters, and the marking pen was used. It is possible to obtain a good ink excellent in storage stability upward and viscosity stability over time, and moreover, it is possible to obtain a marking ink for a writing plate which has good erasability of handwriting or erasability over time. The invention has been completed.

[0006]

In the marking ink composition for writing boards of the present invention, polyoxyethylene polyoxypropylene castor oil, which is a block polymer of a surfactant, is added to the ink composition as one of the additives, and the composition is directed upward as a marking pen. When stored, the storage stability is good and the change in concentration is small because the compatibility with various pigment dispersants used for liquid resin-processed pigments is excellent. On the other hand, as an additive surfactant that improves erasability,
The polyoxyethylene nonyl phenyl ether phosphoric acid ester that has been conventionally used has the same action as the surfactant, has good compatibility with the polyvinyl butyral resin, has the action of softening the polyvinyl butyral resin, and the fatty acid. It is used in combination with an ester to obtain excellent erasability or erasability over time.

Each component of the marking ink composition for a writing board of the present invention will be described below. The pigment is used as a colorant and can be used as long as it can be stably dispersed as fine particles in the ink composition, but especially a chip-shaped resin-processed pigment obtained by kneading the pigment into a resin with a dispersant and a liquid The resin-processed pigment (1) is preferable in terms of dispersibility, stability over time, and workability. The amount used as a pigment component is 1 to 10% by weight, preferably 2 to 6% by weight, based on the total amount of the ink composition. The resin is used to give the ink a film-forming ability, to adhere to the non-writing surface, to give the ink viscosity and pigment dispersion stability.It dissolves in lower alcohols, and polyvinyl butyral resin is good and ink With a low degree of polymerization to reduce the viscosity of, for example, electrified butyral 2000
-L (made by Denki Kagaku Kogyo) is preferable. The amount used is 1 to 10% by weight, preferably 2 to 6% by weight, based on the total amount of the ink composition. In the case of the liquid resin-processed pigment, the resin in the processed pigment can be substituted. The lower alcohol is used as a solvent, and one or more of ethanol, normal propanol, isopropanol, normal butanol, secondary butanol and the like can be used. The amount of these used is 6 with respect to the total amount of ink.
5 to 90% by weight, preferably 72 to 85% by weight. The surfactant is a block polymer polyoxyethylene polyoxypropylene castor oil, and more specifically, a block polymer polyethylene polypropylene group is ether-bonded to the three OH groups of the fatty acid ester portion of the castor oil triricinolein glyceride. Is. A commercially available product is Nikkor PBCO-35. When made into an ink using the surfactant, the compatibility with various dispersants used in various resin-processed pigments is good, the pigment dispersion stability is good, the concentration change due to upward storage is small, and the viscosity stability with time is small. A good ink composition can be obtained. Further, when the surfactant is used, an ink composition excellent in erasability to erasability over time can be obtained by using it together with various fatty acid esters. The amount used is 1 to 8% with respect to the total amount of ink, preferably 2
~ 4%. Examples of the aliphatic carboxylic acid ester include monobasic acid ester, dibasic acid diester, and triester of trihydric alcohol. Specifically, as the monobasic acid ester, butyl oleate, 2-ethylhexyl palmitate, isopropyl isostearate, Examples include isocetyl stearate, isocetyl isostearate, and isostearyl palmitate. Examples of the dibasic acid ester include dioctyl adipate and dioctyl sebacate. As a triester of trihydric alcohol,
Tri (capryl / caprin) glyceryl, glyceryl trioctanoate, glyceryl triisopalmitate, and the like can be used alone or as a mixture of two or more kinds. The amount used is 0.5 to 10%, preferably 3 to 8%.

The ink composition of the present invention is manufactured as follows. In the case of chip-shaped resin processed pigment, put it in a ball mill and add lower alcohol to it.
It is crushed overnight at 0% to obtain a uniform pigment dispersion. In the case of a liquid resin processed pigment, use it as it is. Add various additives and lower alcohol to the tank and dissolve with stirring to form a uniform solution. The above pigment dispersion or liquid resin processed pigment is added to this and stirred to form an ink. However, the above-mentioned production method is merely given as an example, and the method of stirring the addition order of the respective components is not limited as long as a uniform ink composition can be obtained.

[0009]

EXAMPLES The present invention will be described in more detail with reference to the examples below, but the formulations in Table 1 represent% by weight.

[0010]

[Table 1]

(Supplementary explanation of Table-1) (1) BLACK AMBK-2: manufactured by Orient Chemical Co., Ltd., liquid resin processed pigment, carbon black content 10
%, Polyvinyl butyral resin and dispersant 10%, ethanol and isopropanol content 80% (2) BLACK AWB-850: manufactured by Hihiro Vix Co., Ltd., liquid resin processed pigment, carbon black content 10
%, Polyvinyl butyral resin and dispersant 10%, ethanol and isopropanol content 80% (3) BLUE AMBE-4: Orient Chemical Co., Ltd.
Manufactured by, Liquid resin processed pigment, Slen blue pigment content 8%, Polyvinyl butyral resin and dispersant 7.3%, Ethanol and isopropanol content 84.7% (4) RED AMRD-2: Orient Chemical Co., Ltd.
Made by liquid resin processed pigment, organic azo pigment content 7% polyvinyl butyral resin and dispersant 6%, ethanol and isopropanol content 87% (5) Nikkor PBCO-35: Nikko Chemicals Co., Ltd., polyethylene polypropylene glycol mono castor Oil fatty acid ester (6) Nikkor DNPP-4: Nikko Chemicals Co., Ltd.
Made by polyoxyethylene nonyl phenyl ether phosphate ester (7) Phosphanol PE510: Toho Chemical Co., Ltd.
Made by polyoxyethylene nonyl phenyl ether phosphate ester

The marking ink compositions for writing plates obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were placed in a marking pen shaft and were exposed at 50 ° C for up to 1 month. After storage, the ink contained in the batting of the marker shaft was extracted with a centrifuge to examine the rate of increase in viscosity after storage. A marking pen stored at room temperature was written on an enamel plate and tested for initial erasability and erasability over time (one month after writing at room temperature). The results are shown in the table below.

[0013]

[Table 2]

However, ⊚ indicates particularly good, and ∘ indicates good. The same results as those shown in the above table were obtained when the writing plate was composed of a melamine baking plate or a fluorine film.

[0015]

As described above, by using the block polymer polyoxyethylene polyoxypropylene castor oil as the surfactant for the additive, polyoxyethylene nonyl has been conventionally used as the surfactant for the additive. Compared with the case of using phenyl ether, black shows remarkable upward storage concentration stability and viscosity stability, and for other colors, the concentration stability and viscosity are comparable to the case of using the same conventional surfactant. Stability was obtained. In terms of initial erasability and erasability with time, good erasability comparable to that of the conventionally used polyoxyethylene alkyl ether phosphate was obtained.

Claims (1)

[Claims] 1. A marking ink for a writing plate, which comprises a polyvinyl butyral resin, a pigment and a lower aliphatic alcohol, wherein polyoxyethylene polypropylene castor oil which is a block polymer of a surfactant is added as one of the additives. A marking ink composition for a writing board.