Teijin Limited

Tatsuya Ogawa

Hideaki Watanabe

Hisashi Hamano

Yasuhiro Saeki

Masanori Nishiyama

Takao Chujo

Kouhei Endou

Masahiro Hosoi

Masami Etchu

Hideo Katoh

Masayuki Fukuda

Yoshitaka Tanaka

Manabu Kimura

Shigeyoshi Masuda

Kazuteru Kohno

Tomoyuki Kishino

Eiji Kinoshita

Toshifumi Ishikawa

Susumu Taguchi

Hiromichi Ito

Toshio Ishidera

Disclosed are a biaxially oriented polyester film which is excellent in dimensional stability, especially dimensional stability against environmental changes in, for example, temperature and humidity, and a polyester capable of providing the biaxially oriented polyester film with excellent dimensional stability. There is provided a copolymerized aromatic polyester containing aromatic dicarboxylic acid components represented by the following formulae (I) and (II) and a glycol component represented by the following formula (III), wherein  In the structural formulae (I) to (III), Rrepresents an alkylene group having 1 to 10 carbon atoms; Rrepresents a phenylene group or a naphthalenediyl group; and Rrepresents an alkylene group having 2 to 4 carbon atoms or a cycloalkylene group having 8 to 10 carbon atoms.

Copolymerized aromatic polyester, biaxially oriented polyester film, and magnetic recording medium

An object of the present invention is to provide a polyester film having excellent dimensional stability to temperature and humidity. The present invention is a polyester containing a dicarboxylic acid component and a diol component, wherein wherein Ris an alkylene group having 2 to 10 carbon atoms, wherein Ris a phenylene group or naphthalenediyl group; and

Polyester, and composition and film comprising the same

Biaxially oriented polyester film, process for producing the same, and use thereof as substrate for photographic sensitive material

Biaxially oriented polyester film

Biaxially oriented polyester film for magnetic recording media

The film of the present invention is a biaxially oriented laminated polyester film for magnetic recording medium consisting of a polyester layer A containing fine particles and laminated to at least one surface of a polyester layer B, wherein the fine particles in the polyester layer A are composed of 0.001 to 0.03% by weight of crosslinked polymer particles (a) having an average particle diameter (da) of 0.9 to 1.6 &mgr;m, 0.1 to 0.8% by weight of inert particles (b) having an average particle diameter (db) of 0.4 to 0.8 &mgr;m and 0.05 to 1.0% by weight of inert inorganic particles (c) having an average particle diameter (dc) of 0.01 to 0.3 &mgr;m and a Mohs hardness of 7 or above, and the ratio of the thickness TA (&mgr;m) of the polyester layer A to the average particle diameter da (&mgr;m) of the crosslinked polymer particle (TA/da) is in the range of from 0.4 to 2.0. The film has excellent windability, abrasion resistance, transportation durability and electromagnetic conversion characteristics and is producible at a low production cost and useful especially as a base film of a magnetic recording medium for high-speed duplicator.

Biaxially oriented laminated polyester film for magnetic recording medium

A biaxially oriented polyester film which consists of a polyester composition comprising 0.0005 to 0.03% by weight of crosslinked polymer particles having an average particle diameter d.sub.A of 0.8 to 1.6 .mu.m, 0.1 to 0.8% by weight of inert particles having an average particle diameter d.sub.B of 0.4 to 0.8 .mu.m, and 0.05 to 1.0% by weight of inert inorganic particles having an average particle diameter d.sub.C of 0.01 to 0.3 .mu.m and a Moh's hardness of not less than 7, and which satisfies the following equations (1) and (2):

A biaxially oriented laminated polyester film comprising:

Biaxially oriented laminated polyester film having different size

There is provided a biaxially oriented polyester base film for a magnetic tape for use in a cassette for a digital audio tape recorder. The film has (a) a stress when the biaxially oriented polyester base film is extended in the longitudinal direction by 5% of at least 12 kg/mm.sup.2, (b) a residual extension in the longitudinal direction of 0.2% or less and a residual extension in the transverse direction of 0.3% or less, (c) a heat shrinkage in the longitudinal direction of 1.5% or less, (d) at least one surface of which has a surface roughness, Ra, of 25 nm or less, and (e) a film thickness of in the range of from 3 to 12 .mu.m. A magnetic tape for use in a cassette for a digital audio tape recorder is also provided.

Magnetic tape for use in cassette for digital audio tape recorder and

There is provided a biaxially oriented polyester base film for a magnetic tape for use in a cassette for a digital audio tape recorder. The film has (a) a stress when the biaxially oriented polyester base film is extended in the longitudinal direction by 5% of at least 12 kg/mm.sup.2, (b) a residual extension in the longitudinal direction of 0.2 % or less and a residual extension in the transverse direction of 0.3% or less, (c) a heat shrinkage in the longitudinal direction of 1.5% or less, (d) at least one surface of which has a surface roughness, Ra, of 25 nm or less, and (e) a film thickness of in the range of from 3 to 12 .mu. m. A magnetic tape for use in a cassette for a digital audio tape recorder is also provided.

A biaxially oriented film of polyethylene-2,6-naphthalate having a Young's modulus of at least 650 kg/mm.sup.2 in a given direction on the film plane and a direction crossing it at right angles, the difference between the Young's moduli in the two directions being at most 200 kg/mm.sup.2, the difference between the thermal shrinkages in the two directions being 0 to 0.1%.

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Ehime, Japan

Tatsuya Ogawa