초록

Disclosed is an apparatus for formation of high quality plastic sheet in a continuous fashion. Also disclosed are a variety of optical and electronic display applications for high quality plastic sheet produced in a continuous fashion.

대표청구항 ▼

1. A magnetic storage medium comprising a high quality plastic sheet having a magnetic layer disposed on at least one side of the sheet; wherein the plastic sheet is produced by the process comprising the steps of:a) providing molten plastic resin; b) directing the molten plastic resin to an overflo

1. A magnetic storage medium comprising a high quality plastic sheet having a magnetic layer disposed on at least one side of the sheet; wherein the plastic sheet is produced by the process comprising the steps of:a) providing molten plastic resin; b) directing the molten plastic resin to an overflow die having an inlet and an outlet; c) shaping the molten plastic resin into a molten web using said overflow die; d) guiding said molten web away from said overflow die; and e) cooling said molten web to form a solid sheet; wherein the plastic sheet has an optical retardance of 20 nm or less, a thickness variation of 10% or less over a sample length of 400 mm, a roughness of .ltoreq.50 nm over a 0.4 mm length, a waviness of .ltoreq.2.0.mu. in a 20 mm sampling length and a shrinkage of .ltoreq.0.10% upon heating for 4 hours at a temperature below the Tg of the plastic sheet.