Abstract: A biaxially oriented polyester film containing fine particles of insoluble inert substance, has a kinetic coefficient of friction of not more than 0.3, and has microscopic protrusions integrated thereto, said protrusion having an peak-to-valley height of not more than 1 micron mostly range of 0.2 to 0.5 micron. The film having improved slipperiness is useful as the base film of magnetic recording tape for a video tape recorder or a computer data storage.

Abstract: A greenhouse constructed by stretching over a framework a polyethylene terephthalate film oriented in at least one direction and having a refractive index in the oriented direction of 1.57 to 1.78, a refractive index in the thickness direction of 1.48 to 1.57, a density of 1.340 to 1.390 g/cm.sup.3, and a thickness of 50 to 500 microns, as a material for protecting plants from weather exposure.

Abstract: A printed polyester film comprising(I) a biaxially oriented polyester film containing more than 2% by weight to 10% by weight of polyethylene glycol having a molecular weight of 5,000 to 200,000 and a density of 1.390 to 1.410, said film being composed of a polyester in which at least 80% by weight of the entire structural units consists of an ethylene terephthalate unit, and(II) a printed layer formed by a printing ink containing a cellulose derivative as a binder, said printed layer being applied to at least a part of the surface of the film (I),and a process for preparation thereof.

Abstract: A stretch-oriented laminate polyester film consisting of two or three layers of polyester films; both polyester film A and polyester film B which form the external layers of the laminate film are composed of a polyester having an intrinsic viscosity of 0.35 to 1.0, wherein the intrinsic viscosity of a polyester forming the polyester film B is 0.02 to 0.5 greater than that of a polyester forming the polyester film A. The laminate film is curled in the widthwise direction with the polyester film B located inwardly of the curl. This film can be used for various applications, especially as a measuring tape, an adhesive tape and a base of a photographic film.

Abstract: An adhesive film having weatherability comprising (I) a polyethylene terephthalate film base being oriented in at least one direction and having a refractive index, in the orientation direction, of 1.57 to 1.78, a refractive index, in the thickness direction, of 1.48 1.57, a density of 1.340 to 1.390 g/cm.sup.3, and a thickness of 5 to 250 microns, and (II) an adhesive layer coated on at least one surface of said film base (I) either directly or through (III) a layer of a thin metallic film or an adhesive film comprising (I), (II) coated on one surface of (I), and (III) coated on the other surface of (I).

Abstract: A method for heat bonding a polyester film directly with other film or shaped articles of polyester at a temperature below its melting point by using corona discharge treated polyester film, said polyester being predominantly alkylene terephthalate units and/or alkylene 2,6-naphthalate units and the film therefor.