| 摘要 |
PURPOSE:To obtain easily a sheet having the fine skin on the surface, by heating a non-crystalline resin sheet within a specific temperature range after the same has been kept under gaseous pressurizing atmosphere. CONSTITUTION:Gas is dispersed and permeated within a sheet by maintaining a non-foaming sheet under gaseous pressurizing atmosphere. To be more concrete, although flon gas, carbonic acid gas, nitrogen gas, helium gas and argon gas are usable, the flon as whose boiling point is 40--40 deg.C is favorable especially as its dispersion rate is fast. As for pressurizing pressure, in case it is in gaseous state, a range of 3-100kg/cm<2> and that of more than 5kg/cm<2> is especially favorable. As for a keeping period of time of the sheet, though the higher its pressure is and the thinner its thickness is, the shorter it may be, it is desirable to keep the same more than two hours, which is more than 200hr desirably. Then the sheet is heated. A heating temperature is decided at more than 100 deg.C and less than the glass transition temperature (Tg). The heating temperature to the extent of 0.5-10min is desirable.
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