Oriented polyester film for magnetic tape

Abstract

Abstract PURPOSE: To improve resistance to wear, resistance to fatigue and running stability by combining inactive material particles of a specific combination and giving them to a specific refractive index range. CONSTITUTION: Polyester including aluminium silicate of average particle diameter o.8μ or less and volume form coefficient 0.08 or less, calcium phosphate, inactive material (A) such as silica of 0.01W0.28wt%, sedimented calcium carbonate of average particle diameter 1.8μ or less and volume form coefficient 0.08 or more larger than inactive material (A), and inactive material (B) such as heavy calcium carbonate of 0.002W0.019wt% is biaxially orientated, and refractive indexes on two orthogonal axes are set to 1.65 or less and 1.667 or more respectively, thus obtaining a highly oriented polyester film for magnetic tape. Then, it is desirably that the film thickness is about 3W100μ (specially, 8W25μ). COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Shigeru Shiozaki
• 👤 Takao Nakajo
• 👤 Yukio Mitsuishi
• 👤 Atsushi Yamamoto

Bibliographic Details