04/07/2010, Düsseldorf / Gemany

 

Henkel at JEC 2010

 

Wet Peel Ply combines highest bond strength with easy removal

At the JEC 2010 Henkel presents its wide range of product solutions which facilitate the manufacture of composite bonding in aircrafts. Especially for surface preparation Henkel has introduced the new resin-impregnated wet peel plies Hysol EA 9895 and 9896 WPP. Supplied in film form they were developed to increase bonding durability and to eliminate contamination of composite surface from dry peel fragments.

The use of a peel plies is an attractive way for the preparation of composite bonding surfaces. Peel Plies are woven fabrics – usually made out of nylon or polyester – which are generally applied as the final layer in the composite laminate sequence. They are designed to be peeled from the surface after curing to leave a clean and activated surface optimized for bonding of composite structures. However, industry experience has shown that this method to create a bondable surface lacks reliability. Current dry peel plies leave contaminated fibers on the composite surface, which become potential weak spots in bond line durability. To improve on the consistency issue, the prevalent practice is to add a sanding or grit blasting step to ensure satisfactory surface preparation for bonding.

For a long time the industry’s ultimate objective was to develop a surface preparation material and process not requiring any additional surface preparation. Henkel meets this requirement with its innovative wet peel plies, supplied in film form under the Hysol brand. Hysol EA 9895 WPP is a pre-impregnated polyester product which is specially designed for curing at 177°C (350°F). For lower temperatures Henkel recently launched Hysol EA 9896 WPP. Made of nylon it enables best performance at 121°C (250°F).

Both products are compatible with all state-of-the-art composites and provide minimal residual peel ply fibers at the bond surface after curing and removal. Thus, no further processing steps like sanding or solvent wiping are required prior to secondary bond operations. Independent scientific researches made by the University of Washington confirm that Hysol prepared surfaces produce equivalent bond strengths while eliminating the need for secondary surface preparation at the same time.

Compared to traditional peel plies Hysol EA 9895 and 9896 WPP show a greater durability and by this lowers repair cost considerably. In addition aerospace customer benefit from reduced shop time as the fabric stripes easily in one piece. An attribute which makes the wet peel plies from Hysol ideal for the assembly of large composite parts. Hysol EA 9895 has been tested on a variety of current industry prepregs. Since 2008 it is qualified to Airbus, Goodrich and Boeing. Hysol EA 9896 WPP is currently being evaluated by several aerospace customers.

Please come and visit Henkel at booth R45. For further information please do not hesitate to contact us or visit our website at www.henkel.com/aerospace.