US5366783A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laminated polyester film for magnetic tape having specific surface properties
Assignee: Mitsubishi Chemical Corp
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Filing: 1992-03-05
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Granted: 1994-11-22
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Expires: 2012-03-05
Abstract
Abstract A polyester film prepared through a lamination of at least two layers by coextrusion, wherein one of exposed surfaces (surface A) has a center line average roughness of from 0.002 to 0.015 mu m, a polyester layer forming the other of the exposed surfaces (surface B) has a lower melting point than a polyester forming the surface A, and the surface B has a degree of planar orientation of not larger than 0.100, which can be used as a base film for magnetic recording tape having no back coating.
Inventors
- 👤 Shigeo Utsumi
- 👤 Masashi Inagaki
- 👤 Yuko Watanuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:24
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/8404; B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; G11B5/73929; G11B5/73931; G11B5/73935; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/24372; Y10T428/25; Y10T428/31504; Y10T428/31786
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
84 words
A polyester film suitable for a magnetic tape and prepared through a lamination of at least two layers by coextrusion, comprising: a layer of a polyester (A) with an exposed surface having a center line average roughness of from 0.002 to 0.015 μm, a layer of a polyester (B) laminated to polyester (A), polyester (B) having a lower melting point than polyester (A), wherein the layer of polyester (B) has an exposed surface with a degree of planar orientation of not larger than 0.100.
Claim 2
Dependent Claim
84 words
A polyester film suitable for a magnetic tape and prepared through a lamination of at least two layers by coextrusion, comprising: a layer of a polyester (A) with an exposed surface having a center line average roughness of from 0.002 to 0.015 μm, a layer of a polyester (B) laminated to polyester (A), polyester (B) having a lower melting point than polyester (A), wherein the layer of polyester (B) has an exposed surface with a degree of planar orientation of not larger than 0.100.
Claim 3
Dependent Claim
37 words
The polyester film according to claim 1, wherein the polyester (A) forming one of the exposed surfaces of the film is a polymer prepared through a polycondensation reaction of an aromatic dicarboxylic acid with an aliphatic glycol.
Claim 4
Dependent Claim
26 words
The polyester film according to claim 2, wherein the polyester (A) is one selected from the group consisting of polyethylene terephthalate (PET) and polyethylene-2,6-naphthalene dicarboxylate (PEN).
Claim 5
Dependent Claim
37 words
The polyester film according to claim 2, wherein the polyester (B) is a copolymeric polyester which is a copolymerization product of a base polyester component unit used in the polyester (A) with at least one other component.
Claim 6
Dependent Claim
80 words
The polyester film according to claim 4, wherein a total amount of a content in mole % of the copolymerizable component other than the main component of the polyester (A) in the total amount of carboxylic acids in the polyester layer (B) and a content in mole % of the copolymerizable component other than the main component of the polyester (A) in the total amount of diol components in the polyester layer (B) is from 6 to 40% by mole.
Claim 7
Dependent Claim
34 words
The polyester film according to claim 1, wherein the layer (A) contains inert particles having an average particle size of from 0.007 to 2.0 μm in an amount of 0.001 to 0.50% by weight.
Claim 8
Dependent Claim
34 words
The polyester film according to claim 1, wherein the layer (B) contains inert particles having an average particle size of 0.007 to 10 μm in an amount of not larger than 20% by weight.
Claim 9
Dependent Claim
26 words
A laminated polyester film according to claim 7, wherein the layer of polyester (B) contains inert particles having an average size of 0.1 to 0.5 μm.
Claim 10
Dependent Claim
29 words
A laminated polyester film according to claim 8, wherein the inert particles are contained in the layer of polyester (B) in an amount of 1.0 to 5.0% by weight.
Claim 11
Dependent Claim
33 words
A laminated polyester film according to claim 8, wherein the ratio of the thickness of the layer of polyester (B) to the average size of the inert particles is between 0.1 and 10.
Claim 12
Dependent Claim
33 words
A laminated polyester film according to claim 8, wherein the ratio of the thickness of the layer of polyester (B) to the average size of the inert particles is between 0.3 and 1.0.
Claim 13
Dependent Claim
21 words
A laminated polyester film according to claim 8, wherein the layer of polyester (B) has planar orientation not greater than 0.05.
Claim 14
Dependent Claim
21 words
A laminated polyester film according to claim 8, wherein the layer of polyester (B) has planar orientation not greater than 0.03.
Claim 15
Dependent Claim
21 words
A magnetic recording tape comprising a magnetic layer and a base film which is the polyester film according to claim 1.
Claim 16
Dependent Claim
28 words
A laminated polyester film according to claim 1, wherein the ratio of ten-point average roughness to center line average roughness of polyester (B) is not larger than 15.0.
Claim 17
Dependent Claim
28 words
A laminated polyester film according to claim 1, wherein the ratio of ten-point average roughness to center line average roughness of polyester (B) is not larger than 10.0.
Claim 18
Dependent Claim
30 words
A laminated polyester film according to claim 1, wherein the center line average roughness of the exposed surface of the layer of polyester (A) is from 0.003 to 0.011 μm.
Claim 19
Dependent Claim
30 words
A laminated polyester film according to claim 1, wherein the center line average roughness of the exposed surface of the layer of polyester (A) is from 0,004 to 0,009 μm.
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