Dunstone's core product line, our Hi-Shrink Tapes are unique in that they allow the user to control the amount of compressive force applied to the underlying part during the cure process.Some non-shrinking films, such as cellophane, nylon, or polypropylene (OPP), are commonly used to overwrap composite parts to provide compression during cure. They are wrapped, under high tension before the part enters the curing oven. However, these films will relax as the temperature of the cure cycle increases, at the same time that the resin in the composite part begins to drop in viscosity and flow. This is the exact opposite of what you need to ensure good resin flow, and a void free cure.Dunstone Hi-Shrink Tapes will begin to shrink at 70C, and reach maximum shrink force in the 120C to 160C range. Therefore, our tapes will apply the maximum amount of compressive force right when you need it, as your resin begins to flow. This allows for additional ply compaction, elimination of air voids in the part walls, and gives a nice, resin-rich surface finish.The family of Hi-Shrink Tapes is geared to suit applications up to 180C with ETFE and PETTedlar films, and up to 400C with our polyimide shrink product.
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