Abrasion-resistant magnetic recording tape

Claim 1

AS A NEW PRODUCT, A MAGNETIC RECORDING TAPE, NON-BLOCKING AT MODERATELY ELEVATED TEMPERATURES AND NON-CRACKING AT LOW TEMPERATURES, COMPRISING A THIN FLEXIBLE NON-MAGNETIC CELLULOSE ACETATE FILM AND A MAGNETIC COATING FIRMLY ADHERENTLY BONDED THERETO BY A PRIME-COATING OF A BLEND OF A RUBBERY BUTADIENE-ACRYLONITRILE POLYMER AND A COMPATIBLE SPIRIT-SOLUBLE HEATREACTIVE PHENOL-ALDEHYDE RESIN, SAID MAGNETIC COATING BEING A UNIFORM DISPERSION OF ABOUT TWO PARTS OF BLOCKY MAGNETIC IRON OXIDE PIGMENT IN ONE PART OF A BINDER, AND SAID BINDER CONSISTING OF A BLEND OF ABOUT 80 PARTS OF A COPOLYMER OF ABOUT 90 PARTS OF VINYL CHORIDE AND ABOUT 10 PARTS OF VINYL ACETATE AND CORRESPONDINGLY ABOUT 20 PARTS OF A COPOLYMER OF ABOUT 65 PARTS OF BUTADIENE AND ABOUT 35 PARTS OF ACRYLONITRILE, THE TABER ABRASION RESISTANCE VALUE OF THE SAID PRODUCT AS HEREIN INDENTIFIED BEING AT LEAST ABOUT 300 REVOLUTIONS PER MIL.