US5419942A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Base film of digital compact cassette tape
Assignee: Mitsubishi Chemical Corp
•
Filing: 1993-01-14
•
Granted: 1995-05-30
•
Expires: 2013-01-14
Abstract
Abstract A base film of a digital compact cassette tape comprising at least two layers consisting of laminated biaxially oriented polyester films, one surface of which has center line average roughness of 5 to 20 nm, and the other surface of which has center line average roughness of 15 to 45 nm, and which has a Young's modulus in a machine direction of at least 600 kg/mm 2 , which base film is excellent in running stability and electromagnetic conversion characteristics.
Inventors
- 👤 Narihiro Masuda
- 👤 Masashi Inagaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:28
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; G11B5/73935; G11B5/733; G11B5/73929; G11B5/73931; B; B29; B29K; B29K2995/00; B29K2995/0037; B29K2995/0072; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/24372; Y10T428/24942; Y10T428/2495; Y10T428/25; Y10T428/31504; Y10T428/31786
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
145 words
A base film having outer surfaces A and B, which has a Young's modulus of at least 600 kg/mm 2 in a machine direction, which is useful for a digital compact cassette tape, and which comprises two biaxially oriented polyester films which are laminated by coextrusion, wherein one of said two films contains from 0.05 to 1.0% by weight of particles, the particles having an average particle size of 0.05 to 1.0 micrometers and provides the surface A which has a center line average roughness of 5 to 20 nanometers, and wherein the other of said two films has a thickness of at least one micrometer and contains from 1.0 to 10.0% by weight of particles, the particles having an average particle size of 0.1 to 1.0 micrometers, and provides the surface B which has a center line average roughness of 24 to 45 nanometers.
Claim 2
Dependent Claim
145 words
A base film having outer surfaces A and B, which has a Young's modulus of at least 600 kg/mm 2 in a machine direction, which is useful for a digital compact cassette tape, and which comprises two biaxially oriented polyester films which are laminated by coextrusion, wherein one of said two films contains from 0.05 to 1.0% by weight of particles, the particles having an average particle size of 0.05 to 1.0 micrometers and provides the surface A which has a center line average roughness of 5 to 20 nanometers, and wherein the other of said two films has a thickness of at least one micrometer and contains from 1.0 to 10.0% by weight of particles, the particles having an average particle size of 0.1 to 1.0 micrometers, and provides the surface B which has a center line average roughness of 24 to 45 nanometers.
Claim 3
Dependent Claim
15 words
A digital recording cassette tape which contains a base film as claimed in claim 1.
Claim 4
Dependent Claim
16 words
A tape as claimed in claim 2, which further comprises a magnetic layer on surface A.
Claim 5
Dependent Claim
37 words
A base film as claimed in claim 1, wherein each of said films comprises a polyester prepared from an aromatic dicarboxylic acid and a glycol, wherein the polyester may be the same or different in each film.
Claim 6
Dependent Claim
40 words
A base film as claimed in claim 1, wherein each of said films comprises a polyester containing 80 mol % or more of ethylene-terephthalate or ethylene-2-6-naphthalate repeating units, wherein the polyester may be the same or different in each film.
Claim 7
Dependent Claim
24 words
A base film as claimed in claim 1, wherein a layer C is located between the films which provide surface A and surface B.
Claim 8
Dependent Claim
29 words
A base film as claimed in claim 1, wherein the ratio of thickness between the film having Surface A and the film having Surface B is at least 1:1.
Claim 9
Dependent Claim
29 words
A base film as claimed in claim 1, wherein the ratio of thickness between the film having Surface A and the film having Surface B is at least 2:1.
Claim 10
Dependent Claim
23 words
A base film as claimed in claim 1, wherein the center line average roughness of surface A is from 7 to 15 nanometers.
Claim 11
Dependent Claim
17 words
A base film as claimed in claim 1, which further comprises a magnetic layer on surface A.
Claim 12
Dependent Claim
23 words
A base film as claimed in claim 1, wherein surface A has a ten-point average surface roughness of not larger than 200 nanometers.
Claim 13
Dependent Claim
23 words
A base film as claimed in claim 1, wherein the center line average roughness of surface B is from 25 to 35 nanometers.
Claim 14
Dependent Claim
23 words
A base film as claimed in claim 1, wherein surface B has a ten-point average surface roughness of not larger than 500 nanometers.
Claim 15
Dependent Claim
52 words
A base film as claimed in claim 1, wherein the particles present in the two films are the same or different and are selected from one or more of the group consisting of calcium carbonate, amorphous silica, titanium oxide, kaolin, silica particles generated from substantially spherical colloidal silica, and crosslinked polystyrene particles.
Claim 16
Dependent Claim
31 words
A base film as claimed in claim 1, wherein on surface A the number of coarse protuberances larger than 1.62 micrometers is not larger than 5 per 25 cm 2 .
Claim 17
Dependent Claim
31 words
A base film as claimed in claim 1, wherein on surface B the number of coarse protuberances larger than 1.62 micrometers is not larger than 20 per 25 cm 2 .
References Cited (Backward Citations)
US4687700A
Cited
US4687699A
Cited
US4670319A
Cited
US4812360A
Cited
US4876137A
Cited
EP0347646A2
Cited
US5069949A
Cited
US5212006A
Cited
US5316823A
Cited
US5314736A
Cited
US5336079A
Cited
US5366783A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-05-29 | 1998-11-28 | 1999-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-05-29 | 2002-11-28 | 2003-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-05-29 | 2006-11-28 | 2007-05-30 | $7700.00 | Window Closed / Lapsed |