| 摘要 |
PURPOSE:A novel copolymer useful as a light transmitting material for optical memory disc, having specified intrinsic viscosity, molecular weight distribution, melting point, crystallinity, and iodine value, comprising 4-methyl-1-pentene as a main component. CONSTITUTION:(A) 4-Methyl-1-pentene is polymerized alone or copolymerized with (B) 2-20C alpha-olefin (e.g., ethylene, butene-1) except the components A, to give a novel polymer comprising 80-100mol% component A and 0-20mol% component B (the components A+B is 100wt%), having 0.1-1.5dl/g intrinsic viscosity [eta] measured at 135 deg.C in decalin, molecular weight distribution Mw/Mn shown by a ratio of number-average molecular weight to weight-average molecular weight 2-7, 200-245 deg.C melting point measured by differential scanning calorimeter, 10-50% crystallinity measured by X-ray diffraction method and <=2 iodine value. EFFECT:Having improved transparency, melt flow characteristics, and precision molding and processing properties. |
