Abstract: An apparatus for manufacturing multilayer hollow articles having sections different from one another in respect to the kinds of resins, number of layers, and thickness of layers along the circumference in the horizontal section of an article with the narrowest of the sections in any one of the resin layers extending in a specified width along the longitudinal wall of an article and being capable of satisfying the sectional performance requirements. An apparatus is provided for manufacturing multilayer hollow articles with the wall thickness ratio of resin layers in each section varying along the longitudinal wall of an article or those with the sectional width in each resin layer varying along the longitudinal wall of an article. Hollow articles molded by the apparatus of this invention are particularly useful for automotive bumpers, the seats and backs of chairs, and boiler-room doors.

Abstract: This invention provides a blow molding process for manufacturing multilayer hollow articles having sections different from one another in respect to the kind of resins, number of layers, and thickness of layers along the circumference in the horizontal section of an article with the narrowest of the sections in any one of the resin layers extending in a specified width along the longitudinal wall of an article and being capable of satisfying the sectional performance requirements, an apparatus, and said hollow articles. It also provides a process for manufacturing multilayer hollow articles with the wall thickness ratio of resin layers in each section varying along the longitudinal wall of an article or those with the sectional width in each resin layer varying along the longitudinal wall of an article, an apparatus, and said hollow articles.