Biaxially oriented polyester film for magnetic tape

Abstract

Abstract PURPOSE: To enhance the transit properties, the resistance to wear the electromagnetic conversion properites and the like, by securing the ball-type eduction particles independent to each other on the film surface to eliminate the gap between the particles and the polyester and then setting the number of the secondary and the third interference fringes due to the multiple interference method within the specific range per mm 2 . CONSTITUTION: For manufacture of the polyester, the Ca salt soluble to the reaction group is used for the ester exchange reaction catalyst before or under ester exchange reaction and in the amount of about 0.05W0.3mol to the material acid component. Then the 3-valent P/5-valent P compound of the 3-valent and 5-valent P compound each is used in the mol ratio of 1W20, and the P compound is used in 1-W3-fold mol to the using Ca salt before the condensation polymerisation reaction. Thus the polyester is produced. Using such polyester, the biaxially oriented magnetic tape film is obtained. The particles educed into the obtained film contain Ca and P in 1W 15wt% each, and the secondary and the third interference fringes obtained by the multiple interference mathod is set to 30W300pcs./mm 2 and 15pcs./mm 2 or less respectively. As a result, the occurrence of the white powder can be reduced along with the reduced dropout. Thus the magnetic tape which has substantially no properties difference of the width directions of the film can be obtained. COPYRIGHT: (C)1981,JPO&Japio

Inventors

• 👤 Seiji Sakamoto

Bibliographic Details