| 摘要 |
PURPOSE:To prepare highly concentrated dope by a method wherein the level of solvent and the surface of the sediment layer of PVA (polyvinyl alcohol) particulate matter are made nearly parallel to each other and left to stand until the PVA particulate matter swells and turns transparent. CONSTITUTION:Solvent such as dimethyle sulfoxide or the like and PVA are put in a dope preparation vessel in such a manner that the surface of the sediment layer of PVA particulate matter is made parallel to the level of the solvent. In this case, the relationship between the solvent and the PVA satisfies the following formula: 0.5<=D/d<=5, where D represents the distance between the level of the solvent and the bottom of the dope preparation vessel (or the deepest part of the vessel, when the shape of the bottom is not flat) and (d) represents the distance between the surface of the sediment layer of the PvA particulate matter and said bottom. After that, the PVA particulate matter is left to stand so as to swell and turn too transparent to confirm its shape in order to obtain uniform dope. |
