Teijin Limited

Toshifumi Osawa

Mitsuo Tojo

Ieyasu Kobayashi

Makoto Handa

Toshikazu Uchida

Hideaki Watanabe

Masafumi Koseki

Hideshi Kurihara

Hirofumi Murooka

Masanori Nishiyama

Masahiko Kosuge

Sadayoshi Miura

Tsuyoshi Nagai

Akira Kameoka

Tomokatsu Ura

Mitsuio Tojo

Teyasu Kobayashi

Masahito Satoh

Biaxially oriented polyester film and magnetic recording medium

A base film for magnetic recording media, comprising a film layer containing inert fine particles and having an agglomeration rate of the inert fine particles on the surface of the film of 4 to 20%, or a film layer containing inert fine particles and an ester wax of an aliphatic monocarboxylic acid having 8 or more carbon atoms and a polyhydric alcohol and having a water contact angle of the exposed surface of 70 to 90&deg;. A magnetic recording medium, particularly a metal deposited thin film magnetic recording medium comprising this base film is excellent in electromagnetic conversion characteristics.

Magnetic recording medium and base film for the same

Biaxially oriented laminate polyester film for magnetic recording medium

A biaxially oriented laminated polyester film which is excellent in film winding properties and handling properties and provides excellent electromagnetic conversion characteristics when it is used as a base film for high-density magnetic recording media, particularly digital recording magnetic recording media. This film consists of a polyester A layer and a polyester B layer formed on one side of the polyester A layer and is characterized in that: (1) the polyester A layer contains three different types of fine particles which differ from one another in average particle diameter and has a surface roughness WRa of 5 to 20 nm and a WRz of 100 to 300 nm, (2) the polyester B layer has a surface roughness WRa of 2 to 10 nm and a WRz of 30 to 150 nm, and (3) the film has a friction coefficient of 0.5 or less.

Biaxially orientated multi layer polyester film

A biaxially oriented polyester film for magnetic recording media which has (1) a Young's modulus in a machine direction of 5.0 GPa or less and a Young's modulus in a direction perpendicular to the machine direction of 8.0 GPa or more, (2) a surface roughness on one side of 0.3 to 1.5 nm when measured for a measurement area of 246.6&times;187.5 &mgr;m and 0.1 to 3.0 nm when measured for a measurement area of 2.5&times;1.9 mm and a surface roughness on the other side of 0.6 to 2.5 nm when measured for a measurement area of 246.6&times;187.5 &mgr;m and 0.1 to 5.0 nm when measured for a measurement area of 2.5&times;1.9 mm, and, (3) controlled heat shrinkage factors in the machine and transverse directions at 105&deg; C. and 150&deg; C.

Polyester film with specified surface roughness, Young's modulus and heat shrinkage for use as substrate for magnetic recording medium

A biaxially oriented polyester film which has a difference between refractive index on the front side and refractive index on the rear side of the film of 0 to 0.002, a heat shrinkage factor of 0 to 0.6% when it is heated at 105&deg; C. for 30 minutes under no load, a Young's modulus of 4,609 MPa (470 kg/mm ) or more and a difference between the maximum value and the minimum value of Young's modulus on the film plane of 981 MPa (100 kg/mm ) or less, a center line average roughness on the film plane of 2 to 10 nm, and a static friction coefficient of 0.55 or less. A flexible disk having excellent electromagnetic conversion characteristics can be produced by forming an adhesive layer on both sides of the film and a magnetic layer on the adhesive layer.

Biaxially oriented polyester film and flexible disk

A biaxially oriented laminate polyester film (1) has a first polyester layer having a thickness (t ) of 0.3 to 5 &mgr;m and a second polyester layer containing an inert fine particle lubricant and having a thickness (t ) of 1.5 to 9 &mgr;m, or (2) has a first polyester layer having a thickness (t ) of 2 to 8.5 &mgr;m and a second polyester layer containing an inert fine particle lubricant and having a thickness (t ) of 0.6 to 5 &mgr;m. The polyester of the second polyester layer may contain a recovered polyester having the same composition as a recovered laminate polyester film which is the biaxially oriented laminate polyester film or an unstretched film thereof.

Biaxially oriented laminate polyester film

Laminate film with organic particulate for a magnetic recording medium

A composite polyester film comprising (1) a base film C of an aromatic polyester which does not contain or contains inert particles having an average particle diameter of 5 to 2,000 nm in an amount of 0.001 to 5.0 wt % based on the aromatic polyester; (2) a coating layer A on one side of the base film C, which comprises a binder resin, inert particles, a surfactant and a siloxane copolymeried acrylic resin, the outer surface of the coating layer A being not a surface for forming a magnetic layer thereon, and the siloxane copolymerized acrylic resin being contained in an amount of 1 to 50 wt % based on the coating layer A; and, (3) a coating layer B on the other side where the coating layer A is not existent of the base file C, which comprises one member selected from the group consisting of a siloxane copolymerized polyester resin, siloxane copolymerized acrylic resin, silicone and wax, a binder resin, inert particles and a surfactant, the outer surface of the coating layer B being a surface for forming a magnetic layer thereon, and the above member being contained in an amount of 5 to 90 wt % based on the coating layer B when the member is a siloxane copolymerized polyester resin or 1 to 50 wt % based on the coating layer B when the member is other than the siloxane copolymerized polyester resin.

Composite polyester film and magnetic recording medium

A biaxially oriented laminated polyester film comprising a first polyester layer which contains two different types of inert fine particles having different average particle diameters and has a surface roughness of 4 to 15 nm and a second polyester layer which may contain inert fine particles and has a surface roughness of 0.5 to 3.5 nm. The film has a friction coefficient between the first polyester layer and the second polyester layer of 0.5 or less and a good roll form. A cover layer may be further formed on the second polyester layer. The film can be used as a magnetic recording medium by forming a magnetic layer on the second polyester layer or the cover layer overlying the second polyester layer.

Biaxially oriented laminated polyester film

A biaxially oriented laminate polyester film (1) has a first polyester layer having a thickness (t,) of 0.3 to 5 &mgr;m and a second polyester layer containing an inert fine particle lubricant and having a thickness (t,) of 1.5 to 9 &mgr;m, or (2) has a first polyester layer having a thickness (t,) of 2 to 8.5 &mgr;m and a second polyester layer containing an inert fine particle lubricant and having a thickness (t,) of 0.6 to 5 &mgr;m. The polyester of the second polyester layer may contain a recovered polyester having the same composition as a recovered laminate polyester film which is the biaxially oriented laminate polyester film or an unstretched film thereof.

The present invention relates to a low electrostatic composite polyester film comprising a base film C, a coating layer A formed on one side of the base film C, and a coating layer B formed on the other side of the base film C, where (1) the coating layer A is formed of a water-soluble or water-dispersible resin coating inert particles and has a center line average roughness (Ra&minus;A) of the surface of 0.1 to 2 nm; (2) the coating layer B includes 1 to 40 wt % of inert particles and a composition containing a water-soluble or water-dispersible resin, the resin-containing composition containing 5 to 85 wt % of a silicone-modified polyester resin or 1 to 30 wt % of silicone or wax based on the layer B; and (3) the base film C is formed of an aromatic polyester. According to the present invention, it is possible to provide a composite polyester film useful as a base film for a magnetic recording medium that has low electrostatic properties and is excellent in not only blocking resistance and abrasion resistance but also electromagnetic conversion characteristics and adhesion to a back coat.

Lowly electrifiable composite polyester film

A biaxially oriented laminate polyester film in which each of the layers contains at least two different lubricant particles, and each of two members out of the lubricant particles of one layer and each of two members out of the lubricant particles of the other layer have the same substrates and the same average particle diameters, respectively, the biaxially oriented laminate polyester film enables the direct recycling of the recovered polymer for production of the film.

Biaxially oriented laminated polyester film containing at least two different lubricant particles

A film roll in which the distance from the center line of the film roll to the edge of the film extending in a film winding direction is slightly changed in a film breadthwise direction.

Film roll of a thermoplastic resin film

A biaxially oriented polyester film has a first layer of an aromatic polyester containing inert fine particles having an average particle diameter of 1.0 .mu.m or less in an amount of 0.01 to 2% by weight and a second layer of an aromatic polyester. The ratio (t/d) of the thickness t of the first layer to the average particle diameter d of the inert fine particles is 5 to 30. The exposed surface of the first layer has a dynamic friction coefficient (.mu.k.sub.1) against a metal of 0.15 to 0.50, the exposed surface of the second layer has a dynamic friction coefficient (.mu.k.sub.2) against a metal of 0.24 to 0.60, and the ratio .mu.k.sub.2 /.mu.k.sub.1 is 1.2 to 4.0. The film has a thickness of 2 to 8 .mu.m.

Growing community of inventors

Sagamihara, Japan

Toshifumi Osawa