| 摘要 |
PURPOSE: To apply paint to a polypropylene molding with good adhesiveness by simply modifying the surface of the polypropylene molding containing a curved line part by specifying the concn. of fluorine in an atmosphere treating the polypropylene molding and the contact time thereof. CONSTITUTION: A polypropylene molding is brought into contact with an atmosphere with fluorine concn. of 0.1-10% for 1-15min to set the contact angle of the surface of the polypropylene molding to 80 deg. or less. For example, hydrogen of polypropylene is gently substituted with fluorine by dilute mixed gas of 1% fluorine and 99% nitrogen. Fluorine and carbon do not form a covalent bond and are bonded by an ion bond and, as a result, hydrophilicity is increased and, even when the surface of the molding is coated with paint, the molding can be painted with good adhesiveness. Even when the mixed gas of this concn. is used, for example, when a treatment time is increased to 15min or more, a contact angle becomes high. This phenomenon shows that the ion bond of fluorine and carbon is converted to a covalent bond as the contact chance with the gas increases and hydrophilicity transfers to hydrophobicity. |
