EP0124291A2
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EP
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Biaxially oriented polyester film
Assignee: Teijin Ltd
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Filing: 1984-03-30
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Granted: —
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Expires: 2004-03-30
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 micrometer, (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, 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 a distribution curve showing the relation between the heights x in micrometers of said many protrusions on the film surface and the number y of the protrusions having the height x per mm 2 does not cross a straight line represented by equation (1) within the range of log10y> 1.
Inventors
- 👤 Tsutomu Kiriyama
- 👤 Shigeru Horie
- 👤 Tetsuo Ichihashi
- 👤 Masahiro Oshida
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 04:10
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: 20
Claim 1
Independent Claim
214 words
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 micrometer 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 stated length 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, wherein T 2 is the tension of the film which has been caused to travel over a fixed rod of SU S 304 stainless steel having an outside diameter of 5 mm, and T 1 is its tension before passage over the fixed rod, and (3) there is the following relation between R CLA and µk,
Claim 2
Dependent Claim
214 words
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 micrometer 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 stated length 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, wherein T 2 is the tension of the film which has been caused to travel over a fixed rod of SU S 304 stainless steel having an outside diameter of 5 mm, and T 1 is its tension before passage over the fixed rod, and (3) there is the following relation between R CLA and µk,
Claim 3
Dependent Claim
17 words
A film according to claim 1 wherein there is the following relation between R CLA and pk,
Claim 4
Dependent Claim
37 words
A film according to claim 1 or 2 which has a number of minute protrusions on its surface, said protrusions being attributed to fine particles of anatase-type titanium dioxide and calcium carbonate included in the polyester base.
Claim 5
Dependent Claim
88 words
A film according to claim 3 wherein the fine particles of titanium dioxide have a particle size distribution ratio (y), defined by the following equation, of from 1.2 to 2.3, wherein D 25 is the particle diameter of the particles when the cumulative weight of these particles is 25% based on their entire weight, and D 75 is the particle diameter of the particles when the cumulative weight of these particles is 75% of their entire weight, the cumulative weights being calculated beginning with the largest particle size.
Claim 6
Dependent Claim
28 words
A film according to claim 3 wherein the calcium carbonate particles have a particle size distribution ratio (y), defined as in claim 4, of from 1.5 to 2.3.
Claim 7
Dependent Claim
38 words
A film according to claim 3 or 4 wherein the titanium dioxide particles have an average particle diameter of 0.1 to 0.5 micrometer and do not substantially contain particles having a particle diameter of at least 4 micrometers.
Claim 8
Dependent Claim
21 words
A film according to claim 6 wherein the titanium dioxide particles have an average particle diameter of 0.15 to 0.47 micrometer.
Claim 9
Dependent Claim
38 words
A film according to claim 3 or 5 wherein the calcium carbonate particles have an average particle diameter of 0.3 to 1.5 micrometers and do not substantially contain particles having a particle diameter of at least 4 micrometers.
Claim 10
Dependent Claim
21 words
A film according to claim 8 wherein the calcium carbonate particles have an average particle diameter of 0.4 to 1.4 micrometers.
Claim 11
Dependent Claim
34 words
A film according to any one of claims 3, 4, 6 and 7 wherein the amount of the titanium dioxide particles is 0.01 to 2.5% by weight based on the weight of the polyester.
Claim 12
Dependent Claim
27 words
A film according to claim 10 wherein the amount of the titanium dioxide particles is 0.05 to 2.0% by weight based on the weight of the polyester.
Claim 13
Dependent Claim
34 words
A film according to any one of claims 3, 5, 8 and 9 wherein the amount of the calcium carbonate particles is 0.01 to 0.3% by weight based on the weight of the polyester.
Claim 14
Dependent Claim
27 words
A film according to claim 12 wherein the amount of the calcium carbonate particles is 0.02 to 0.28% by weight based on the weight of the polyester.
Claim 15
Dependent Claim
42 words
A film according to claim 3 wherein the amount of the titanium dioxide particles is 0.1 to 0.5% by weight and the amount of the calcium carbonate particles is 0.1 to 0.3% by weight, both based on the weight of the polyester.
Claim 16
Dependent Claim
48 words
A film according to any one of claims 3, 4, 6, 7, 10, 11 and 14 wherein the titanium dioxide particles contain 0.25 to 1.0% by weight, as P 2 0 5' of oxygenated phosphorus, and 0.1 to 0.3% by weight, as K 2 0, of oxygenated potassium.
Claim 17
Dependent Claim
96 words
A film according to any one of the preceding claims wherein 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 obtained by plotting the height x in micrometers of protrusions on the film surface on the x axis and the number y of protrusions having the height x per mm 2 on the y axis of a logarithmic scale does not cross a straight line represented by the equation (1) within the range of log lo y> 1.
Claim 18
Dependent Claim
54 words
A film according to claim 16 wherein the surface has such a protrusion distribution that the distribution curve does not cross a straight line represented by the equation (2) wherein x and y are as defined for equation (1) in claim 16, and the protrusions are attributable mainly to fine particles of titanium dioxide.
Claim 19
Dependent Claim
35 words
A film according to claim 16 or 17 wherein the maximum value of the distribution curve is present within a range satisfying the following expression, wherein y and x are as defined for expression (1).
Claim 20
Dependent Claim
31 words
A magnetic recording medium comprising a biaxially oriented polyester film as claimed in any one of the preceding claims and a magnetic layer on one or both surfaces of said film.
References Cited (Backward Citations)
No citation records indexed.
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