| 摘要 |
PURPOSE:To reduce a manufacturing cost by enabling a polyester sheet to be continuously easily manufactured from recovered or below grade polyester resin of a low limiting viscosity number as a raw material by a method wherein a uniaxial stretching polyester resin sheet of 5-120% in a degree of stretching, which is composed of polyester resin of 0.40-0.63 in limiting viscosity number, is manufactured. CONSTITUTION:Recovered polyester resin or the like as a raw material is ground, casted into a two-shaft screw extruder with a vacuum deaerator as it is undried, and pressure inside a cylinder is reduced. The raw material polyester is melted in the extruder, comes to have a water content of 500ppm or under, extruded in a sheet-form from a die for molding the sheet of a T-die, and cooled with a roll to form a sheet of 125-1000mum in thickness. Then, the sheet is heated, and stretched by 5-120% as a rectangular component in an advance direction of the sheet with a known uniaxial horizontal stretching machine or the like. A limiting viscosity number of polyester composing a uniaxial stretching polyester sheet obtained thus is 0.40-0.63. |
