Abstract: The present invention aims to provide a transparent electromagnetic wave shield member, which is free from a moirè phenomenon which could not be solved by the prior art, and in which an excellent electromagnetic wave shielding properties and a sufficient total light transmittance based on an appropriate network structure are compatible, and a method for manufacturing the same. The transparent electromagnetic wave shield member of the present invention is a transparent electromagnetic wave shield member in which a metal layer of an electroconductive metal network structure having a geometrical shape is formed on a transparent substrate, and which is characterized in that a spacing of said network structure is 200 ?m or less, an opening ratio of the network structure is 84% or more, and in addition, a thickness of the electroconductive metal layer is 2 ?m or less.

Abstract: The present invention provides a polyester film particularly useful as a base film for a magnetic recording medium such as cassette-type magnetic tape of a digital recording mode and a production process thereof. The polyester film is produced by irradiating UV light onto a surface of a film in a non-stretched stage or a stage prior to the completion of stretching to form fine protrusions on the surface. The fine protrusions on the film surface are specified by the ratio of 10-point average roughness Rz to center line average roughness Ra (Rz/Ra) on the surface (less than 20), the difference in concentration of carboxyl groups between the surface layer part and the inside of the film, and the number of fine protrusions.

Abstract: The object of this invention is to provide a biaxially oriented polyester film suitable as a base film for high density magnetic recording media, small in track deviation and excellent in traveling durability and preservability, and to provide a production method thereof. The object of this invention can be achieved by a biaxially oriented polyester film, characterized in that the dimensional change rate (A) in the transverse direction of the film is in a range of −0.3 to 0% when the film is allowed to stand at 49° C. and 90% RH for 72 hours, while being loaded with 32 MPa in the machine direction.

Abstract: A polyester film, comprising a non-liquid crystal polyester (A) and a copolyester (B) containing mesogen groups in the main chain to form a phase separated structure in the non-liquid crystal polyester (A), and the dispersed domains of the copolyester (B), having forms to satisfy the following formulae (1) and (2):0.02<(I/J)<50 (1)K<1/2.times.S[I, J] (2)where I, J and K are form indicators expressing the average form of the plurality of domains existing in the film: I is the average length of the dispersed domains of the copolyester (B) in the machine direction of the film; J, that in the transverse direction; and K, that in the normal direction: and S is a function for selecting the shorter value of the lengths I and J; if I>J, S[I, J] means J, and if I<J, S[I, J] means I. If the copolyester (B) has such geometrical forms, the polyester film obtained is excellent in rigidity, high toughness, heat shrinkage, clarity, surface properties, long-time thermostability, electric properties, etc.

Abstract: A novel polyester film and a process for its preparation are disclosed wherein said film is composed of (a) liquid crystal polyester; (b) non-liquid crystal polyester; and (c) fiberizer capable of substantially fiberizing said liquid crystal polyester (a). Said polyester film shows remarkable improvements in various properties compared with the prior art polyester films: polyester film according to the present invention exhibits: (a) a high modulus of elasticity; (b) a high toughness; (c) a small content of: (1) oligomer, (2) thermal decomposition products and (3) gelation products; and (d) excellent electrical properties, so that this film can be used as a base film for electrical insulating material, capacitors, magnetic recording mediums, etc.