HYDROGENATED STYRENE POLYMER AND OPTICAL-DISK SUBSTRATE

Title:

HYDROGENATED STYRENE POLYMER AND OPTICAL-DISK SUBSTRATE

Document Type and Number:

WIPO Patent Application WO/2001/048031

Kind Code:

A1

Abstract:

An optical-disk substrate which is satisfactory in transferability and releasability during molding, is reduced in warpage, and has high strength. The optical-disk substrate is made of a hydrogenated styrene polymer in which the content of nucleus-hydrogenated styrene units is 80 wt. % or higher and which has a reduced viscosity (in toluene, 0.5 dl/g, 30°C) of 0.3 to 0.6 dl/g, the radius-direction shrinkage of the disk as measured at the glass transition temperature of the hydrogenated styrene polymer being 4.5% or lower. Also provided is a hydrogenated styrene polymer which is suitable for producing the optical-disk substrate. In this polymer, the content of nucleus-hydrogenated styrene units is 80 wt. % or higher. The polymer has a glass transition temperature of 130°C or higher and has a relaxation spectrum at 200°C satisfying the following relationship (1) log(H($g(t))• $g(t)) ≤ 6.5(10?-2¿ ≤ $g(t) ≤ 10?4¿) [wherein log is common logarithm; $g(t) is relaxation time (sec); and H$g(t)(Pa) is the relaxation spectrum at 200°C].

Inventors:

KIDO NOBUAKI (JP)
MATSUMURA SHUNICHI (JP)
IWATA KAORU (JP)
NITTA HIDEAKI (JP)
TAKEUCHI MASAKI (JP)
HASHIDZUME KIYONARI (JP)

Application Number:

PCT/JP2000/009329

Publication Date:

July 05, 2001

Filing Date:

December 27, 2000

Export Citation:

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Assignee:

TEIJIN LTD (JP)
BAYER AG (DE)
KIDO NOBUAKI (JP)
MATSUMURA SHUNICHI (JP)
IWATA KAORU (JP)
NITTA HIDEAKI (JP)
TAKEUCHI MASAKI (JP)
HASHIDZUME KIYONARI (JP)

International Classes:

C08F8/04; C08F12/08; G11B7/253; G11B7/2533; G11B7/243; G11B7/2433; G11B7/258; G11B7/2585; G11B7/259; G11B7/2595; (IPC1-7): C08F8/04; C08F12/00; G11B7/24

Foreign References:

JPH10116442A

1998-05-06

Other References: