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).

公开(公告)号：DE2500546A1

公开(公告)日：1976-07-15

申请号：DE2500546

申请日：1975-01-08

Applicant: BASF AG

Inventor： ROLLER HERMANN ,  WOLLNIK MANFRED DIPL ING DR ,  HARTMANN HANS-JOERG DIPL ING D ,  GUTERMANN WINFRIED ,  MUENZNER WULF DIPL ING DR

IPC: C09D5/23 ,  G11B5/735 ,  G11B5/68 ,  B05D5/12 ,  H01F10/02

Abstract: In the prepn. of a flexible layered tape, the magnetic layer is prepd. from a dispersion of magnetisable particles in a soln. in an organic solvent of a polymeric binder. This dispersion is applied to one side of a flexible synthetic tape provided on the other side with an adhesive intermediate layer (Z) based on a vinylidenechloride copolymer, contg. 70% vinylidene chloride, and a back layer (R) containing polymer bound carbon black. A dispersion is prepd. of 15-30 wt. % carbon black and 2-8 wt. % of a de-lustering agent in a binder of 62-83 wt. % elastomeric, isocyanate gp. free polyesterurethane, an epoxide resin (ratio 4:1) and non volatile polyisocyanates. The latter are present in an excess of 100-400 equiv. % over the quantity of isocyanate groups needed for crosslinking of total reactive groups in the layer R. This dispersion of carbon black is applied to the layer Z which contains 1-15 wt. %, relative to solids content of the copolymer of Di-n-octyltin-bis (2-ethyl-hexyl thioglycolate) (1). Esp. useful for video tapes.