| 摘要 |
PURPOSE:To eliminate solvent in the formation of adhesive layer by a method wherein adherent plastic film and writable and erasable plastic film are co- extruded onto the surface of a sheet acting as the support by means of a T-die. CONSTITUTION:A film 2 made of polyethylene ionomer as adherent resin and a film 3 made of ethylene tetrafluoride-ethylene copolymer as writable and erasable resin are co-extruded onto a milk-white polyester sheet 1 respectively at the extrusion temperature of 230-250 deg.C and of 300-340 deg.C in the order named so as to bring the film 2 into contact with the sheet 1 and contact-bonded by being past between nip rolls and cooling rolls in order to cool and solidify. Because co-extrusion is employed, the thickness of the films 2 and 3 are freely controlled and the thickness of the film 3 can be made thinner than 10mum or less and consequently the consumption of fluoroplastics material and the like is reduced and accordingly the production cost of product can be reduced. Furthermore, because the formation of adhesive layer is done solventless, the product is pollution-free. |
