Patent ID: 6241376
Filing Date: 2001-06-05
Classification: B01F,B29B,G11B,Y10S,Y10T

Abstract:
A process for the preparations of a magnetic dispersion for magnetic coating with magnetic particles having a coercive force of more than 120 kA/m, a relative residual induction of Mr/Mn of at least about 0.9 and an orientation ratio of at least 2.7 by means of a single-shaft blade-type kneading apparatus (V) having at least one kneading blade (S1-S3), the shaft (W) rotating in a housing (K) having a housing wall 5 and at the same time oscillating in the axial direction (arrow O) for kneading a mixture of magnetic particles a in a thermoplastic binder and a solvent, comprising the following featuresa) the radial shear gradient in the gap (s) between the tip of the kneading blade (S1-S3) and housing wall 5 is about 150 to 1600, 1/secb) the circumferential velocity of the kneading blade (S1-S3) is from about 20 to about 80 cm/sec.