Solid epoxy prepregs with patterned resin distribution: Influence of pattern and process parameters on part quality in vacuum-bag-only processing

Solid resins (SR) are fully reactive resin systems that are solid at room temperature. Up to a critical temperature they can be quasi- infinitely molten and solidified without any relevant curing reaction. This study deals with novel SR-based prepregs where a dry textile is covered with a regular SR ( uncured) pattern, allowing for storage and draping at room temperature. The manufacturing of SR prepregs with accurate pattern geometries and the processing of the same into laminates with a pore volume content <1% using a vacuum bag only process is demonstrated for four pattern types and two curing cycles. The study furthermore shows that the pattern design has an influence on the mandatory drying phases as well as on fiber undulations. With sufficiently long drying phases, equivalent pore volume contents and interlaminar shear strength could be obtained with different pattern types.