Abstract: Orientated semi-crystalline polyester films characterized in that they have a planar orientation coefficient .DELTA.p of greater than or equal to 165.times.10.sup.-3 and a degree of transverse shrinkage of less than or equal to 2.7% at 200.degree. C.These films are suitable as a support for obtaining composite films by extrusion-coating of an olefin polymer.

Abstract: Composite polyester films, well adapted as either thick or thin film bases, e.g., for the graphic arts or for packaging, are comprised of a crystalline or semicrystalline polyester film substrate (A), said film substrate (A) having a coating, e.g., a coextrudate, of an oxysulfonylated copolyester adhesion primer on at least one of the face surfaces thereof, and said oxysulfonylated copolyester comprising admixture of (a) a crystalline or semicrystalline polyester, and (b) an oxysulfonylated copolyester wherein the number of oxysulfonylated recurring units, relative to 100 recurring units of like monomer, range from 3 to 20, and the respective amounts of the components (a) and (b) are such that the number of oxysulfonylated recurring units in the mixture relative to the total number of recurring units of like monomer, ranges from 2 to 15%.

Abstract: A thick composite polyester film of between 40 and 300 microns in thickness being crystalline or semicrystalline comprising drawn unfilled layer (A) of thickness e, covered on at least one surface thereof with a thin drawn filled layer (B) of thickness e.sub.2, having an overall roughness greater than 0.3 microns and being filled with inert particles wherein the volume median diameter of the filler being at least equal to the thickness of layer (B); the thickness ratio of layers (A) and (B) denoted by e.sub.1 /e.sub.2 is lower than 5% and the percentage of scattered light transmitted from the composite film is lower than 7.

Abstract: The invention relates to composite thermoplastic polyester films with outstanding transparency, low surface roughness and good machinability.These films contain, in at least one outer layer, 0.1 to 1% of fine particles with a volume median diameter of between 0.6 and 1.5 micrometers.After being metallized, these films produce highly glossy films with a particularly low gloss difference between the 2 faces.

Abstract: The invention relates to composite thermoplastic polyester films with outstanding transparency, low surface roughness and good machinability. These films contain, in at least one outer layer, 0.1 to 1% of fine particles with a volume median diameter of between 0.6 and 1.5 micrometers. After being metallized, these films produce highly glossy films with a particularly low gloss difference between the 2 faces.

Abstract: Biaxially drawn, advantageously filled multilayer polyester film substrates, well adapted for the manufacture of magnetic recording tapes, are comprised of a composite of at least two adjacent layers of biaxially stretched thermoplastic polyester film, at least one of the face surfaces thereof having a roughness defined by a plurality of dome and peak protuberances extending therefrom, said domes being present in a concentration of at least 5 per mm.sup.2 and having heights of at least 9/100 of one micron, the ratio of the height of such dome protuberances to the diameter of the base thereof being less than 1/100, and the ratio of the height of such peak protuberances to the diameter of the base thereof being at least 1/100.