Claims
- 1. A polyester film for use as a support layer for optical recording media comprising a polyester as a major component, characterized in that the polyester film has a modulus of photoelasticity of not more than 0.9.times.10.sup.-3 mm.sup.2 /kgf, a maximum surface roughness Rt of not more than 100 nm and a mean interval Sm between adjacent projections in the surface of the film of not less than 20 .mu.m.
- 2. The polyester film of claim 1, wherein the polyester is prepared by reacting a bifunctional carboxylic acid and/or an ester-forming derivative thereof, which contains not less than 10 mol % of, a diphenyldicarboxylic acid and/or a derivative thereof with a dihydroxy compound and/or an ester-forming derivative thereof.
- 3. The polyester film of claim 2, wherein the diphenyldicarboxylic acid or the derivative thereof is at least one member selected from the group consisting of diphenyl-2,2'-dicarboxylic acid and derivatives thereof and, diphenyl-2,3'-dicarboxylic acid and derivatives thereof.
- 4. The polyester film of claim 2 or 3, wherein the derivative of the diphenyldicarboxylic acid is at least one member selected from the group consisting of diphenyl ether dicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenyl thioether dicarboxylic acid, diphenyl ketone dicarboxlic acid and diphenylethanedicarboxylic acid.
- 5. The polyester film of claim 1, wherein the glass transition point Tg of the polyester film is not lower than 80.degree. C.
- 6. An optical recording medium comprising the polyester film of any one of claims 1-3.
- 7. An optical recording medium comprising the polyester film of claim 5.
Priority Claims (2)
Number |
Date |
Country |
Kind |
62-215732 |
Aug 1987 |
JPX |
|
62-283391 |
Nov 1987 |
JPX |
|
Parent Case Info
This application is a continuation of application Ser. No. 07/350,621, filed Apr. 25, 1989, now abandoned.
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
4719171 |
Ikenaga et al. |
Jan 1988 |
|
4899168 |
Osato et al. |
Feb 1990 |
|
4965307 |
Okabe et al. |
Oct 1990 |
|
5047278 |
Ono et al. |
Sep 1991 |
|
Foreign Referenced Citations (4)
Number |
Date |
Country |
0227043 |
Jul 1987 |
EPX |
62-247807 |
Oct 1987 |
JPX |
0252513 |
Jan 1988 |
JPX |
3081022 |
Apr 1988 |
JPX |
Continuations (1)
|
Number |
Date |
Country |
Parent |
350621 |
Apr 1989 |
|