JPH0119709B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention provides a writing board that allows clear writing on a writing board made of a non-absorbent material, such as a writing board made of synthetic resin or enameled iron plate, and that can be easily wiped with an eraser. The invention relates to ink for commercial use. (Prior Art) When a dye is used as a coloring agent in writing board ink, if it is left unused for a long time without being wiped off, the dye will stain the writing board surface, making it difficult to completely erase handwriting. For this reason, it is preferable to use pigments as colorants, but when pigments are used, the degree of dispersion tends to be asymmetric, and the stability is poor, and the coloring phenomenon may decrease during storage, making it difficult to obtain clear handwriting. Therefore, there are commercially available writing board inks that eliminate these drawbacks by dispersing pigments in a solution that uses a ketone solvent as a solvent and a nonionic surfactant. However, since ketone solvents have safety and odor problems, it is desired to use alcohol-based solvents, which are safer. However, inks using alcohol-based solvents have problems with stability over time and wipeability, and no satisfactory product has yet been found. (Object of the Invention) The present invention aims to solve the above-mentioned problems and provide an ink for writing boards that has good stability over time using an alcohol solvent, can be written clearly, and can be easily wiped off with an eraser. It is complete. (Structure of the Invention) The present invention dissolves a synthetic resin in an alcoholic solvent, and also dissolves a higher aliphatic hydrocarbon, a polyoxyalkylene alkyl ether type nonionic surfactant, a sorbitan ester type nonionic surfactant, and a polyoxyethylene alkyl A pigment is dispersed in a solution in which one or both of ether phosphate nonionic anionic surfactants are dissolved. The alcohol-based solvent-soluble synthetic resin used in the present invention is polyvinyl butyral resin,
Polyvinyl alcohol resin, ethyl cellulose resin, polyvinyl ether resin, maleic acid resin,
This synthetic resin, such as styrene maleic acid resin, is essential for forming a uniform film that fixes pigments. Further, as the alcohol solvent, alcohols such as butyl alcohol, ethyl alcohol, and propyl alcohol, or alcohols to which glycol ethers such as ethylene glycol and monoethyl ether are added are used. Although the alcoholic solvent has lower toxicity and odor than the ketone solvent, it dissolves the above-mentioned film-forming synthetic resin well and uniformly disperses the pigment. In addition, by dissolving the pigment particles in this alcohol-based solvent and dispersing them more uniformly, higher aliphatic hydrocarbons such as liquid paraffin and mineral spirits are used as release agents from the surface of the writing board. This makes it easy to wipe off pigments adhering to the surface of the writing board. Furthermore, the polyoxyalkylene alkyl ether type nonionic surfactant, which is compatible with the alcohol solvent together with the higher aliphatic hydrocarbon, is necessary as a film forming aid in order to form a uniform film together with the synthetic resin, One or both of the sorbitan ester type nonionic surfactant and the polyoxyethylene alkyl ether phosphate type nonionic surfactant are desorption aids that soften the synthetic resin and improve the releasability of the film. A polyoxyalkylene alkyl ether type nonionic surfactant as a film forming aid, and a sorbitan ester type nonionic surfactant or a polyoxyethylene alkyl ether as a release aid. As a result of many experiments, it has become clear that when used in combination with a surfactant, the dispersion stability and stability over time of the pigment are poor, a hard film is formed, the erasability is significantly impaired, and the intended purpose cannot be achieved. Ta. Next, as pigments, in addition to carbon black (black), azo pigments such as Lake Red C (red), permanent carmine (red), and chromophthal scarlet (red), phthalocyanine blue (blue), and phthalocyanine green (green) are used. ), phthalocyanine pigments such as phthalocyanine pigments, condensed polycyclic pigments such as thren blue (blue), and other organic pigments. Examples Transparent polyvinyl butyral resin was used as the synthetic resin, ethyl alcohol, n-propanol and n-butanol were used as the alcohol solvents, liquid paraffin was used as the higher aliphatic hydrocarbon, and polyoxyalkylene alkyl ether type nonionic surfactant was used. Neugen DL-0206 (trade name, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was used as a sorbitan ester type nonionic surfactant, Nonion OP-83RAT (trade name,
(manufactured by NOF Corporation) is used as a polyoxyalkylene alkyl ether phosphate ester type nonionic anionic surfactant, Plysurf A212C (trade name,
(manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) to obtain the ink for writing boards shown in the formulation table below. All of these had good stability over time, were clearly written on the writing board made of enameled iron, and could be easily erased with an eraser. In addition, all the numerical values in the table are weight %.

【table】

[Table] (Effects of the invention) As is clear from the above description, the present invention has the following effects:
Because it uses an alcohol-based solvent without using a ketone-based solvent, it is safer, has low toxicity, and has low odor, and uses a synthetic resin that is soluble in alcohol-based solvents as a film-forming agent. Not only does it have good coverage, but the pigment is well dispersed, resulting in uniform and stable color development.Furthermore, since it contains higher aliphatic hydrocarbons, it is extremely easy to wipe off with an eraser even after a long period of time. It is. Furthermore, since a polyoxyalkylene alkyl ether type nonionic surfactant is blended as a film forming aid, the synthetic resin forms a uniform film with excellent color development. Since either or both of an ionic surfactant and a polyoxyalkylene alkyl ether phosphate ester type nonionic anionic surfactant are blended, this softens the synthetic resin and acts as a desorption aid, making it easy to wipe. It has the advantage of being easy to erase. Therefore, the ink for writing boards of the present invention has good stability over time, can be written clearly, and can be easily wiped off with an eraser, making a great contribution to the industry.

Claims (1)

[Claims] 1 Dissolve a synthetic resin in an alcoholic solvent, and dissolve a higher aliphatic hydrocarbon, a polyoxyalkylene alkyl ether type nonionic surfactant, a sorbitan ester type nonionic surfactant, and a phosphate ester type nonionic surfactant of polyoxyethylene alkyl ether. An ink for writing boards comprising a pigment dispersed in a solution in which one or both of ionic and anionic surfactants are dissolved.