A manufacturing method, for an abrasive tape used for the burnishing of items such as floppy disks, which significantly reduces resulting scratches. An abrasive tape is manufactured by the steps of applying a coating liquid which contains as a major composition abrasive particles and a binder resin to a flexible substrate; drying the flexible substrate to produce an abrasive layer; and subjecting the abrasive layer to a surface smoothing treatment in order to align the tip ends of the abrasive particles to a uniform position by passing the abrasive layer between pressure rollers in such a manner that the flexible substrate comes in contact with an elastic roller, whereas the abrasive layer comes in contact with a metal roller, and wherein the pressure rollers are composed of the elastic roller having a hardness of 50-80 measured by a spring type hardness tester A and the metal roller, and are arranged opposite to each other.
The method for testing burnishing tape includes placing the tape on a backing surface and applying a force normal to the abrasive surface of the tape in a localized area of the tape surface. Thereafter, an increasing pulling force is applied to the end of the tape up to a point where the tape moves under the effect of the normal force. Through prior burnishing tape product testing a known normal force N is determined and a delamination pulling force D is likewise determined, such that a burnishing tape can be said to be defective where it is placed under a normal force N and the pulling force required to move it is less than the delamination pulling force D. The values of N and D are determinable for different types of burnishing tape and thereafter utilizable to test further quantities of similar burnishing tape. The testing device of the present invention includes a tape supporting plate, a force gauge for applying a known normal force N to the abrasive surface of the burnishing tape disposed on the plate, and a variable torque motor with a torque sensor that is utilized to apply a known variable pulling force to the tape, such that the pulling force required to move the tape under the normal force N can be determined and then compared to the predetermined delamination force D. Where the pulling force required to move the tape is less than D the tape is determined to be defective, whereas when the pulling force required to move the tape is greater than D the bonding strength of the abrasive layer of the burnishing tape is determined to be adequate such that the burnishing tape can be confidently utilized to burnish hard disk surfaces.
An abrasive tape is disclosed, comprising a flexible support having thereon an abrasive layer containing mainly an abrasive particle and a binder resin, wherein said abrasive layer has a thickness of from 0.3 to 10.0 .mu.m, an interlayer is provided between said abrasive layer and said flexible support, the thickness of said interlayer is 1 .mu.m or more, 30% or more of the thickness of said flexible support and larger than the thickness of said abrasive layer, and said interlayer has a Young's modulus of from 10 to 150 Kg/mm.sup.2. The abrasive tape may be used for cleaning and polishing a magnetic head.
