US5006589A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyester film for magnetic recording media
Assignee: Mitsubishi Chemical Corp
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Filing: 1989-06-02
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Granted: 1991-04-09
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Expires: 2009-06-02
Abstract
Abstract Disclosed in this invention is a polyester film for magnetic recording media, containing 0.05 to 5% by weight of inactive inorganic particles (A) having a Mohs hardness of 6 or above and an average particle size of 0.005 to 1.0 μm and 0.01 to 2.0% by weight of inactive particles (B) having an average particle size which is greater than that of the particles (A) and in the range of 0.1 to 3.0 μm, the polyester film having an intrinsic viscosity in the range of 0.52 to 0.65. The polyester film of this invention is excellent in abrasion resistance, scuff resistance and slitting qualities and useful as a base film for magnetic recording media.
Inventors
- 👤 Seiji Sakamoto
- 👤 Chikakazu Kawaguchi
- 👤 Yoshio Meguro
- 👤 Takashi Harada
- 👤 Toshifumi Takisawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:58
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73937; C; C08; C08J; C08J5/00; C08J5/18; C08K; C08K3/00; C08K3/18; C08K3/20; C08K3/22; C08L; C08L67/00; G11B5/733; C08J2367/00; C08K2003/2227; C08K2201/00; C08K2201/002; C08K2201/005; C08K2201/009; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
100 words
A polyester film for magnetic recording media, containing 0.05 to 5% by weight of inorganic particles (A) selected from the group consisting of particles of δ- aluminum oxide and particles of γ- aluminum oxide both having a Mohs hardness of 6 or above and an average particle size of 0.005 to 1.0 μm, and 0.01 to 2.0% by weight of inactive particles (B) having an average particle size which is greater than that of said particles (A) and in the range of 0.1 to 3.0 μm, the polyester film having an intrinsic viscosity in the range of 0.52 to 0.65.
Claim 2
Dependent Claim
100 words
A polyester film for magnetic recording media, containing 0.05 to 5% by weight of inorganic particles (A) selected from the group consisting of particles of δ- aluminum oxide and particles of γ- aluminum oxide both having a Mohs hardness of 6 or above and an average particle size of 0.005 to 1.0 μm, and 0.01 to 2.0% by weight of inactive particles (B) having an average particle size which is greater than that of said particles (A) and in the range of 0.1 to 3.0 μm, the polyester film having an intrinsic viscosity in the range of 0.52 to 0.65.
Claim 3
Dependent Claim
17 words
A polyester film according to claim 1, wherein the inactive particles (B) are particles of heat-resistance polymer.
Claim 4
Dependent Claim
25 words
A polyester film according to claim 1, wherein the inactive particles (B) are inert particles which precipitate in the course of the polyester producing process.
Claim 5
Dependent Claim
27 words
A polyester film according to any of claims 1, 2 or 3, wherein the refractive index of the film in its thickness direction is 1.492 or above.
Claim 6
Dependent Claim
40 words
A polyester film according to any of claims 1, 2 or 3, wherein the thickness of the film is 12.0 μm or less and the F-5 value of the film in the machine direction is 12.0 kg/mm 2 or greater.
Claim 7
Dependent Claim
59 words
A polyester film according to any of claims 1, 2 or 3, wherein the double-refractive index Δn of the film defined by the following formula (1): Δn=n.sub.TD -n.sub.MD (1) wherein n TD is refractive index of the film in the transverse direction, and n MD is refractive index of the film in the machine direction, is 0.010 or above.
References Cited (Backward Citations)
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JPS5278953A
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