公开(公告)号：DE2501372A1

公开(公告)日：1976-07-22

申请号：DE2501372

申请日：1975-01-15

Applicant: BASF AG

Inventor： ROLLER HERMANN ,  WOLLNIK MANFRED DIPL ING DR ,  HARTMANN HANS-JOERG DIPL ING D ,  FALK ROLAND DIPL CHEM DR ,  GUTERMANN WINFRIED ,  REUTHER ECKHARD DIPL PHYS DR

IPC: C09D5/23 ,  G11B5/735 ,  G11B5/68 ,  B05D5/12

Abstract: Flexible magnetic recording tapes are coated on the reverse side with a 0.5-2 mu m thick non-magnetic conductive layer (A) of conductive pigments and opt. other pigments, with total pigment content 15-80 wt %, in a polymer binder, and an outer non-magnetic layer (B) with thickness 0.3-1 um, of a polymer binder with pigment content 0-10%. The tapes are coated with (A) using a polyester-urethane binder with added polyisocyanate, in an inert volatile org. solvent, drying, and coating with (B) using a binder contg. OH gps. with a solids content of which 0-10 wt % is an accelerator for the addn. reaction to the NCO gps., 0-30% is a lubricant and 0-10% is a non-magnetic pigment. Wear resistance of the back of the tape is improved by coating with (B). Even after 500 passes through a video-recorder, only sight signs of wear are visible, whereas without (B) signs of abrasion can be seen after 10-20 passes and even good commercial tapes show heavy wear after 150 passes. The surface conductivity, and roughness required for good winding performance, are not adversely affected by presence of (B).