Toray Industries, Inc.

Tetsuya Tsunekawa

Takuji Higashioji

Hirofumi Hosokawa

Kenji Tsunashima

Masaaki Kotoura

Yukari Nakamori

Tetsuya Gotoh

Masayoshi Asakura

Keiichi Egawa

Akira Kubota

Kenichi Etou

Syunichi Osada

Tetsuya Machida

Seiji Fukuda

Shoji Nakajima

Shigetoshi Maekawa

Shunichi Osada

Shozi Nakajima

Hiroshi Mataki

Kenichi Eto

Hikaru Yamagata

Tetsuya Yamagata

Chie Makiyama

An object of the invention is to provide a laminated film which hardly gives transmission loss based on reflection or scattering, is excellent in heat resistance and humidity resistance, and has an arbitrarily-controlled refractive index distribution. Accordingly, the invention is a laminated film comprising 5 or more laminated resin layers; the thickness of each of the resin layers being from 1 to 100 nm; and the film having a layer structure wherein the thicknesses of resin layers having the same composition A, out of the resin layers, increase or decrease from the side of a surface of the laminated film toward the side of the other surface opposite thereto.

Laminated film

An objective of the present invention is to provide a film that has a high rigidity and is superior in dimension stability under high temperatures and transparency after heating processes, as well as in moldability within a wide temperature range, which has not been achieved by conventional techniques, and this objective has been achieved by a laminated film that includes 50 or more layers each of which is made of a thermoplastic resin and has a thickness of less than 30 nm or a biaxial oriented polyester film that has a density in a range from 1 to 1.4 g/cm, a heat shrinkage of &#x2212;2 to 2% in the longitudinal direction at 180&#xb0; C. and a breaking elongation in a range of 100 to 1000% in at least one direction.

Multilayer film and biaxially oriented polyester film

In order to provide a film having excellent heat resistance, thermal dimensional stability, and mechanical properties, in particular, a film capable of satisfying required properties, e.g., higher strength in accordance with the reduction in thickness of a base film, improved thermal dimensional stability and mechanical properties in a use environment, and higher heat resistance and improved thermal dimensional stability in accordance with the needs for miniaturization and more functionality in electrical and electronic areas, a thermoplastic resin is allowed to contain transition metal oxide particles, and is formed into a biaxially oriented thermoplastic resin film, wherein the melting point of the film is allowed to become higher than the melting point of the thermoplastic resin to be used. Preferably, the difference between a peak temperature (melting point T) of the heat of fusion in the first run of the measurement of the biaxially oriented thermoplastic resin film with a differential scanning calorimeter (DSC) and a peak temperature (melting point T) of the heat of fusion in the second run is allowed to satisfy the following Formula.2&#xb0; C.&#x2266;T-T&#x2266;30&#xb0; C. Alternatively, the plane orientation factor of the biaxially oriented thermoplastic resin film containing the transition metal oxide particles is controlled at 0.120 or more and less than 0.280.

Biaxially oriented thermoplastic resin film

The object of the present invention is to provide a method for producing a polyester film excellent in rigidity, toughness, dimensional stability, electric properties, etc. and less in thickness fluctuation and surface defects, hence very suitable as a film for various industrial materials such as magnetic recording media, capacitors, heat transfer ribbons and thermal mimeographic stencil paper. The first method of the present invention is a method for producing a polyester film, in which a film made of a resin mainly composed of a polyester is simultaneously biaxially stretched by a simultaneously biaxially stretching tenter oven, comprising the step of effecting small-ratio stretching at an area stretching ratio of 1.0005 to 3.0 times three times or more, to achieve a total area stretching ratio of 25 to 150 times, and the second method of the present invention is a method for producing a polyester film, in which a film made of a resin mainly composed of a polyester is stretched using a simultaneously biaxially stretching tenter oven, comprising the step of effecting a series of operation consisting of stretching and subsequent relaxation twice to less than 10000 times, to achieve a total area stretching ratio of 25 to 150 times.

Polyester film and a production method thereof

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.

Polyester film and method for producing the same

An object of the present invention is to provide a high-quality biaxially oriented film exhibiting an excellent electromagnetic conversion property, traveling durability, magnetic head traveling performance, etc. as a magnetic recording medium. The object of the present invention is achieved by a biaxially oriented film including a polymer alloy composed of polyester (polymer 1) and a thermoplastic resin (polymer 2) other than the polyester as essential components, wherein micro protrusions having a height of 2 to 50 nm are formed at a density of 1,000,000 to 90,000,000/mmon at least one surface.

Biaxially oriented film having specified micro protrusions

An object of the present invention is to provide a biaxially oriented high quality polyester film excellent in thermal dimensional stability and clarity and also excellent in productivity, and also to provide a production process thereof. Another object is to provide a biaxially oriented polyester film greatly improved in the practical properties respected in various applications of the polyester film, such as the recording track shift in magnetic recording tape application, curling in magnetic recording card application, dimensional change during process in printing plate application, printing shift in ribbon application, thermostability in capacitor application, and perforation sensitivity and low temperature curling in heat-sensitive mimeograph stencil application. The objects of the present invention can be achieved by a biaxially oriented polyester film, comprising a polyester (A) mainly composed of ethylene terephthalate and a polyether imide (B), having a single glass transition temperature, and having a refractive index of 1.60 to 1.80 at least in either the machine direction or the transverse direction.

Biaxially oriented polyester film, and a production method thereof

A polyester film for use in a capacitor having high heat resistance, which consists of a biaxially oriented film containing a polyester (A) as a main component and a polyimide (B) and has a glass transition temperature of 105&#xb0; C. to 145&#xb0; C. and an elongation at break in the machine direction of 70% to 150%, offers a high glass transition temperature and excellent insulation volume resistance and insulation breakdown voltage at high ambient temperatures. This film can produce a metallized film for use in a capacitor having high heat resistance and also a film capacitor having high heat resistance.

Polyester film for heat-resistant capacitor, metallized film thereof, and heat-resistant film capacitor containing the same

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 &minus;0.3 to 0% when the film is allowed to stand at 49&deg; C. and 90% RH for 72 hours, while being loaded with 32 MPa in the machine direction.

Biaxially oriented polyester film, process for producing the same, and magnetic recording medium

The present invention provides a polyester film, which is composed of a polyester resin and a polyimide resin, having superior oligomer-restraining property and dimensional stability. This polyester film also has improved surface conditions, that is, has a reduced number of projections on the surface, and hence, the polyester film shows superior electromagnetic conversion characteristics when used for magnetic recording media. In particular, this polyester film is effectively used for high-density magnetic recording media. This film is composed of a polyester resin and a thermoplastic resin other than a polyester resin, and has a number H1 of coarse projections 0.28 &mgr;m or more in height of 0 to 100/100 cm on at least one surface of the polyester film and a number H2 of coarse projections 0.56 &mgr;m or more in height of 0 to 10/100 cm on the same surface.

Polyester film and magnetic recording medium using the same

A biaxially oriented polyester film that is 7.0 GPa or more in either the Young's modulus in the machine direction (YmMD) or in the transverse direction (YmTD), and in the range of 55&deg; or more and 85&deg; or less in the circumferential half-width of the diffraction line from the crystal plane in the direction of the polyester's backbone chain that is determined through crystal orientation analysis by wide angle X-ray diffractometry performed while rotating the polyester film around its normal. The film is high in rigidity in all directions within the film plane, high in tear resistance, high in dimensional stability, and resistant to deformation under load, and have very great industrial advantages as material for high-density magnetic recording media, with wide applicability as material for electrostatic capacitor, heat transfer ribbon, and base paper for thermosensitive stencil printing.

Process of making biaxially oriented polyester films

Polyester film and production method thereof

The objects of the present invention can be achieved by a biaxially oriented polyester film, comprising a polyester (A) mainly composed of ethylene terephthalate and a polyether imide (B), having a single glass transition temperature, and having a refractive index of 1.60 to 1.80 at least in either the machine direction or the transverse direction.

Biaxially oriented polyester film and production method thereof

Disclosed is a biaxially oriented polyester film that is 7.0 GPa or more in either the Young's modulus in the machine direction (YmMD) or in the transverse direction (YmTD), and in the range of 55&deg; to 85&deg; in the circumferential half-width of the diffraction line from the crystal plane in the direction of the polyester's backbone chain that is determined through crystal orientation analysis by wide angle X-ray diffractometry performed while rotating the polyester film around its normal. The film is high in rigidity in all directions within the film plane, high in tear resistance, high in dimensional stability, and resistant to deformation under load, and have very great industrial advantages as material for high-density magnetic recording media, with wide applicability as material for electrostatic capacitor, heat transfer ribbon, and base paper for thermosensitive stencil printing.

Biaxially oriented polyester films and their production methods

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):

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Otsu, Japan

Tetsuya Tsunekawa