Development of a flexible injection and impregnation chamber for pultrusion of high reactive resins

Pultrusion is an established and efficient process for the production of continuous fiber-reinforced composites using resin systems such as unsaturated polyesters and vinyl esters. Highly reactive resins like polyurethane and amine epoxy have been in use for a few years. These resin classes stand out due to an extended spectrum of properties. This opens up new fields of application for the pultrusion technology, but poses challenges for the processing technology. Pot lifes in the range of a few minutes require a continuous process: closed injection pultrusion (CIP). Various approaches to the design and layout of the internal geometry of the injection and impregnation chambers (ii-chamber) are the subject of ongoing research. Numerous factors influence the impregnation process in the ii-chamber as well as the quality of the resulting composite. Within the scope of this study, the influencing variables of the impregnation process in the ii-chamber have been analyzed and e valuated. The main influencing variables and their impact were determined. Based on the selection of the influencing variables, a concept for an ii-chamber has been developed using product development methods. This approach allows fast and flexible adjustment of the main influencing variables in the process. The chosen strategy enables the derivation of suitable die and process parameters for the processing of novel materials for pultrusion. The ii-chamber concept has been implemented and validated by experimental processing of a novel PU resin system in the pultrusion process.