Preform for producing containers (90) comprising a neck section (8), a wall section (6) and a bottom section (7), which is composed of a multi-layer structure comprising three layers, the one of which (1) is directed inwardly respective the preform and is composed of a primary material (PM) thereby forming a primary basis layer (1). Said primary material consists of a synthetic material. A further layer (3) is directed outwardly with respect to said primary layer (1), in such a way that it forms the outer surface layer (3) of the preform, thereby consisting of a tertiary material (TM) forming a tertiary surface layer (3). Said tertiary layer is composed of a further synthetic material. Said preform is remarkable in that an intermediate layer (2) is provided between the primary and tertiary layers (1, 3) which is composed of a secondary material (SM) consisting of a fluid. Process and device for manufacturing said preform.