| 摘要 |
PURPOSE:To enhance gas barrier properties without any increase in material thickness by surface-treating a resin-made barrel with an SO3 gas or an SO3- containing fluid. CONSTITUTION:A barrel 1 for a writing implement is surface-treated by exposure to an SO3 gas or an SO3-containing mixed gas. An SO3-containing liquid may also be used for the surface treatment. The barrel is preferably formed from an olefin resin such as polyethylene and polypropylene. These resins ar widely used in view of ease of molding and cost thereof. Further, such a resin have excellent gas barrier properties, and are chemically stable. However, the reaction system using SO3 is extremely active, and therefore reacts easily with the resin to form sulfonate groups on the surface of the barrel, thereby enhancing the gas barrier properties. |
