Extrusion blow molding methods and articles made thereby

A method for making an extrusion blow-molded article, the method comprising the steps of:

• extruding a tubular parison of molten thermoplastic material from an annular throat of a die;
• enclosing the parison in a mold and closing one end of the parison, the mold having a side wall inner surface encircling a central longitudinal axis of the mold and having a base wall inner surface adjacent the closed end of the parison;
• providing a circumferentially extending groove in the side wall inner surface of the mold at a location spaced longitudinally from the base wall inner surface;
• and
• inflating the parison to cause the parison to expand against and conform to the side wall and base wall inner surfaces of the mold to form an article comprising a base wall and a tubular side wall;
• wherein during the inflating step the molten thermoplastic material is blown into the groove in the mold such that the groove is substantially entirely filled by the molten material so as to form a solid flange extending radially outwardly from the side wall of the article.