| 摘要 |
PROBLEM TO BE SOLVED: To provide a stabilized, sharp display of writing lines at all times by using dispersion liquid in which a dispersion medium is an organic solvent and a densifying agent is fatty acid bisamide having hydroxyl with the melting point of specified value and providing the yield value in the dispersion liquid. SOLUTION: The structure of a network formed in dispersion liquid by a densifying agent is accelerated by heating, and when the temperature is close to the melting point, particles in the densifying agent are swollen and bulkly to control the movement of magnetic particles more than required and generate a dangerous state in which recording and erasing cannot be carried out. On the other hand, the densifying agent is swollen and dispersed in a solvent to form a colloid gel structure and the effect is demonstrated, and the state in which the melting point is too high is not preferable from the viewpoints of safety and processability. Therefore, fatty acid bisamide having a hydroxyl and also having the melting point of approximately 120 deg.C-160 deg.C is used as the densifying agent. As the dispersion medium, a nonpolar solvent such as oils or aliphatic hydrocarbon and a polar solvent such as glycols or alcohols are used. |
