The tendency of polyester films to attract dust and develop scratches is reduced by applying to each side of such films a coating having a perceptible thickness of at most 0.1 .mu. and essentially consisting of 70 to 90 percent by weight of a waxy material having a melting point about 75.degree. C and 30 to 10 percent by weight of an antistatic compound.
A leader tape for a magnetic recording tape having a coating layer consisting of a binder and a white pigment. A surface resistivity of the coating layer is less than 10.sup.12 ohms/sq. and a transmissivity of the leader tape is more than 20 percent. This is a continuation of application Ser. No. 244,421, filed Apr. 17, 1972, now abandoned.
A laminated film for a super-high density magnetic recording medium, which comprises (A) a layer composed of a thermoplastic resin and (B) a layer of a thermoplastic resin containing fine particles therein. In this laminated film, the outer surface of the layer (A) has a surface roughness of less than 0.005.mu. as expressed as the Ra value, and the outer surface of the layer (B) has a surface roughness of 0.005 to 0.040.mu. as expressed as the Ra value. The outer surface of the layer (B) has either (i) a plurality of depressions and a plurality of protrusions, which are formed thereon in a configuration such that at least one protrusion exists within each depression or at least one protrusion exists in the area where two or more depressions are contiguous to each other, or (ii) protrusions on a flat plane and a covering layer (C) composed of a lubricant, which is formed on the surface of the layer (B). This covering layer (C) may be formed on the surface having the above-mentioned depressions and protrusions. The covering layer (C) is a continuous film layer or a discontinuous film layer formed of worm-like nodules. When a ferromagnetic metal thin film is formed on the surface of the layer (A) by vacuum evaporation and a protective film layer is formed on this thin film, there is obtained a vacuum-deposited video tape excellent in running properties and electromagnetic transformation performance. In this vacuum-deposited video tape, the transfer of the surface configuration due to the coarseness of the running surface can be prevented.
A laminated film comprising (A) a layer composed of a thermoplastic resin and (B) a layer composed of a thermoplastic resin containing fine particles therein, wherein a discontinuous skin having a height of 50 to 1,000 .ANG. is formed on the outer surface of the layer (A) and the outer surface of the layer (B) has a surface Ra value of 0.005 to 0.040.mu.. The laminated film is very valuable as a base film of a magnetic recording tape having a ferromagnetic metal thin film formed on the surface of the layer (A), especially a video tape, because it has good running properties and is excellent in electromagnetic transformation performance.