| 摘要 |
PROBLEM TO BE SOLVED: To provide a process by which a relatively large quantity of a magnetic dispersion can be economically prepared and a magnetic coating having good magnetic values and magnetic characteristics can be realized. SOLUTION: This process consists of producing a magnetic dispersion for a magnetic-particle-containing magnetic coating having a coercive force of above 120 kA/m, a relative remanence induction Mr/Mn of at least about 0.9, and an orientation rate of at least 2.7 by means of a single axis blade type kneader having a shaft (W) which revolves within a machine frame having a machine frame wall (K), simultaneously vibrates in the axial direction, and has the function of kneading a thermoplastic resin binder and a magnetic particle mixture in a solvent, wherein (a) the radial shear gradient in the gap (s) between the tip of the kneading blade and the machine frame wall (K) is about 150 to about 1,600, particularly, about 500 to about 1,400 1/sec, and (b) the peripheral speed of the kneading blade is about 20 to about 80, particularly, about 35 to about 60 cm/sec. The thus produced magnetic dispersion can be used to produce an information recording medium and an image recording medium having a particularly high recording and memory speed. |
