§
Luxuse
Patent Intelligence
Sign In
← Back to Patent Explorer
US4619869A Expired / Lapsed US ⏱️ 0.0 years remaining

Biaxially oriented polyester film

Assignee: Teijin Ltd
•
Filing: 1985-07-15
•
Granted: 1986-10-28
•
Expires: 2005-07-15
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A biaxially oriented film of a film-forming aromatic polyester derived from an aromatic dicarboxylic acid as a main acid component and an aliphatic glycol as a main glycol component, said film having surface properties such that (1) it has a surface flatness, R CLA , of from 0.001 to 0.016 micron, (2) it has a coefficient of travelling friction, μk, of from 0.01 to 0.20, and (3) the following relation is established between R CLA and μk, 0.10≦10×R.sub.CLA +μk≦0.31. Preferably, said film has many minute protrusions on its surface which are attributed to fine particles of titanium dioxide or of both titanium dioxide and calcium carbonate, and has such further surface property that (4) a distribution curve showing the relation between the heights of said many protrusions on the film surface and the numbers of the protrusions having the respective heights does not cross a straight line represented by the following equation (1) log.sub.10 y=-8.0x+4.34 (1) where x and y are as defined above, within the range of log 10 >1.

Inventors

  • 👤 Tsutomu Kiriyama
  • 👤 Shigeru Horie
  • 👤 Tetsuo Ichihashi
  • 👤 Masahiro Oshida

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-28 16:13
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B29; B29C; B29C48/00; B29C48/022; B29C48/03; B29C48/07; B29C48/08; B29C55/00; B29C55/02; B29C55/10; B29C55/12; C08G; C08G63/00; C08G63/02; C08G63/12; C08G63/16; C08G63/18; C08K; C08K3/00; C08K3/18; C08K3/20; C08K3/22; C08K3/24; C08K3/26; C08L; C08L67/00; C08L67/02; G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; G11B5/73937; G11B7/00; G11B7/24; G11B7/241; G11B7/252; B29K; B29K2067/00; C08J2367/00; C08J2367/02; C08K2003/2237; C08K2003/2241; C08K2201/00; C08K2201/002; C08K2201/005; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31786

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 222 words
A magnetic recording medium comprising (a) a biaxially oriented film of a film-forming aromatic polyester derived from an aromatic dicarboxylic acid as a main acid component and an aliphatic glycol as a main glycol component, said film having surface properties such that (1) it has a surface flatness, R CLA defined by the following equation, of from 0.001 to 0.016 micron, ##EQU6## wherein R CLA is the flatness of the film surface determined by the center line average method, f(x) is the sum of vertical distances from a straight line with a length L drawn across a film surface roughness curve measured by using a needle-contacting type surface roughness tester and being nearly parallel to the base line of said curve to maximum and minimum points of said curve respectively, and L is the length stated above for use in calculating f(x) in the surface roughness curve, (2) it has a coefficient of travelling friction, μk, defined by the following equation, of from 0.01 to 0.20, ##EQU7## wherein T 2 is the tension of the film which has been caused to travel on a fixed rod of SUS 304 stainless steel having an outside diameter of 5 mm, and T 1 is its tension before passage over the fixed rod, and (3) the following relation is established between R CLA and μk,
Claim 2
Dependent Claim 222 words
A magnetic recording medium comprising (a) a biaxially oriented film of a film-forming aromatic polyester derived from an aromatic dicarboxylic acid as a main acid component and an aliphatic glycol as a main glycol component, said film having surface properties such that (1) it has a surface flatness, R CLA defined by the following equation, of from 0.001 to 0.016 micron, ##EQU6## wherein R CLA is the flatness of the film surface determined by the center line average method, f(x) is the sum of vertical distances from a straight line with a length L drawn across a film surface roughness curve measured by using a needle-contacting type surface roughness tester and being nearly parallel to the base line of said curve to maximum and minimum points of said curve respectively, and L is the length stated above for use in calculating f(x) in the surface roughness curve, (2) it has a coefficient of travelling friction, μk, defined by the following equation, of from 0.01 to 0.20, ##EQU7## wherein T 2 is the tension of the film which has been caused to travel on a fixed rod of SUS 304 stainless steel having an outside diameter of 5 mm, and T 1 is its tension before passage over the fixed rod, and (3) the following relation is established between R CLA and μk,
Claim 3
Dependent Claim 16 words
01≦10×R CLA +μk≦0.31, and (b) a magnetic layer on one or both surfaces of said film.
Claim 4
Dependent Claim 16 words
01≦10×R CLA +μk≦0.31, and (b) a magnetic layer on one or both surfaces of said film.

References Cited (Backward Citations)

US4025694A Cited
US4304807A Cited
US4505966A Cited
US4497865A Cited
US4546030A Cited
US4539260A Cited
US4546036A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1989-10-27 1990-04-28 1990-10-28 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1993-10-27 1994-04-28 1994-10-28 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1997-10-27 1998-04-28 1998-10-28 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag