Sleeve molding apparatus and methods for making multi-layer injection
molded plastic articles in successive mold cavities. In a first molding
step, an inner sleeve is molded on a core in a first mold cavity, which
may comprise a full body length sleeve or only a partial sleeve, such as
an upper neck finish portion. The sleeve and core are withdrawn from the
first mold cavity while the sleeve is still warm, and transferred without
substantial delay to a second mold cavity for injection molding an outer
layer which bonds to the inner sleeve. By transferring the sleeve at an
elevated temperature into the second mold cavity, an improved bond is
formed between the inner sleeve and outer layer which resists separation
during a later reheat stretch blow molding step, and/or in use of the
resulting article. In a preferred embodiment, a pasteurizable beer
container is provided having a finish-only sleeve of a PEN polymer. In a
second embodiment, a returnable and refillable water container is
provided having a full-length body sleeve of a PEN polymer. A
multi-station injection molding apparatus is provided having a transfer
mechanism, such as a rotatable turret or reciprocating shuttle, for
cost-effective manufacture of preforms simultaneously in multiple cavity
sets.