| 摘要 |
PURPOSE:To provide a polyvinylidene fluoride series bi-directionally oriented film, prominent in resistances to heat and contamination, by a method wherein the film is constituted of a composition containing the essential ingredient of polyvinylidene fluoride and the copolymer of vinylidene fluoride - hexafluoropropylene series. CONSTITUTION:The composition of material should contain the essential ingredient of polyvinylidene fluoride and the copolymer of vinylidene fluoride - hexa fluoropropylene series and a blend ratio between the polyvinylidene fluoride and the copolymer of vinylidene fluoride - hexafluoropropylene series should be 30-95wt% of vinylidene fluoride constituent. In case it is up to 30wt%, the strength of the film is low and a durable orientation can not be effected in a tubular bi-axial orientation. Further, the film, prominent in thermal stability, can not be obtained. On the other hand, in case it exceeds 95wt%, the property of biaxial orientation is reduced and the variability of the thickness of the film is increased or the transparency of the film is deteriorated. The property of orientation may be improved by adding the limited amount of polymethyl methacrylate resin. The blend rate of polymethyl methacrylate resin is preferable to be 25wt% or less. |
