In this paper, we would like to present a new polyolefin polymer, “Zeonex”, which has outstanding characteristics for optical uses.

As an optical disk substrate such properties as high clarity, low retardation, high heat resistance, and high humidity resistance properties are required. Glass can satisfy these requirements, but it is fragile and not suitable for mass production. PMMA has high clarity but has poor heat resistance and low humidity resistance. Polycarbonate, on the other hand, shows high heat resistance, but poor humidity resistance [1].

Nippon Zeon has developed a new polyolefin polymer, Zeonex, which clearly satisfies all of these requirements [2]. It has excellent features, especially:

1. a. low retardation: less than 20nm by Rotating Analyzer Ellipsometer

2. b. high heat resistance: Tg 140 °C by Differential Scanning Calorimeter

3. c. high humidity resistance: negligibly small linear expansion of disks in high humid conditions

4. d. low tilt of disk: less than 5 milli radian by Automatic Tilt Angle Tester

5. e. high transfer rate of patterns from stampers to disks

6. f. easy processing in injection molding

This paper touches upon composition, physical and molding properties of the polymer, and disk properties made from it, in comparison with those of PMMA and polycarbonate.