CYCOM 5320-1 composite prepreg resin system

CYCOM 5320-1 is a toughened epoxy prepreg resin system from Syensqo, a composite prepreg for out-of-autoclave and vacuum-bag-only manufacturing of aerospace structural parts. The resin is supplied pre-impregnated on carbon fibre reinforcement in unidirectional tape and woven fabric formats, and is intended for primary and secondary structure and for prototype structural parts.

The system handles like standard prepreg but can be cured under a vacuum bag to give laminates with very low porosity, without an autoclave. After a post-cure at 350 °F (177 °C), the maker states that it reaches mechanical properties equivalent to other toughened epoxy prepreg systems cured in an autoclave at that temperature. The laminate can be post-cured free-standing after an initial low-temperature cure, and the material can also be cured under positive pressure in an autoclave or a press. Low-temperature cure capability allows low-cost tooling, which is useful for prototypes and for larger drone and eVTOL airframe components.

The main properties are listed in the technical datasheet. Shelf life is one year when stored below 10 °F (-12 °C), tack life is 20 days at room temperature and shop life is at least 30 days at room temperature. The cured resin density is 1.31 g/cc, the wet glass transition temperature is 324 °F (163 °C) by DMA, and average moisture uptake is 0.55 wt %. For integrators, the long tack and shop life gives time for layup of large or complex parts, and the wet glass transition temperature sets the hot, wet service limit of the structure.

Product forms with supporting property databases include IM7 12K 145 gsm unidirectional tape, T650-35 3K 8-harness satin fabric, IM7 plain weave fabric, T650-35 3K plain weave fabric, and T650-35 12K 145 gsm unidirectional tape. The data for the last two forms is available from NCAMP, and the other forms from Syensqo on request. Forms for automated fibre placement and automated tape laying are listed. The maker describes the processing as optimized for monolithic laminates and for honeycomb sandwich parts.

In the example datasheet processing, a vacuum bag only hold at room temperature for 16 hours is followed by a cure of 10 hours at 200 °F and a post-cure of two hours at 350 °F under the same bag. The qualified material specifications describe it as a low initial temperature, vacuum-bag-only cure, medium toughness epoxy prepreg. The datasheet reports lamina and laminate mechanical properties for hot and wet conditions, including tensile, compression, shear and notched properties.

Typical applications are structural airframe parts for aircraft, including unmanned aircraft and eVTOL, such as wing skins, spars, fuselage panels and sandwich structures, and the prototype tooling-light parts that precede them.