METHOD OF ELIMINATING DEFECTS WHILE EXTRUSION COATING FILM USING SPEED CONTROL OF THE NIP ROLL

It has now been determined that an internal optical defect can be eliminated by controlling the relative speed mismatch between the resilient roll and the casting roll in a film extrusion coating process. In particular, slowing down the surface speed of the resilient roll relative to the casting roll when coating a biaxially orientated film was found to remove the optical defect. Conversely, speeding up the surface speed of the resilient roll relative to the casting roll when coating a uniaxially orientated film was found to remove the optical defect.