| 摘要 |
PURPOSE:To obtain a key sheet having high sticking work efficiency and requiring a short exposure time by using a biaxially oriented polystyrene film having >=45g rigidity according to a bending test method, <=1.5% clouding degree and 70- 150mum thickness. CONSTITUTION:A biaxially oriented polystyrene film having >=45g rigidity in both longitudinal and lateral directions according to a bending test method using ''Handle-O-Meter '', <=1.5% clouding degree and 70-150mum thickness is used as a key sheet for sticking for a photomechanical process. A mixture of polystyrene and a styrene copolymer satisfying said conditions may be used. Since the film has high transparency, a short exposure time is required, and the firm film results in high sticking work efficiency. In addition, the polymer is inexpensive, so the sheet is economical. |
