Pentex is a polyethylene napthalate polyester fiber. It has two times the stretch resistance of regular Dacron polyester and Pentex offers a high modulus alternative for woven Dacrons. It is best when used in a laminate form. Pentex has similar tenacity to polyester and slightly better UV resistance. This fiber is developing an impressive track record as a laminate.
Pentex is a fairly new fiber to sailmaking. It looks, feels and behaves very much like Dacron, but it has less stretch per a given weight. Early attempts to weave it like traditional Dacron did not work as well as planned. We are not giving up yet and our suppliers are still trying to perfect this weaving process.
The good news is this fiber lends itself very well to laminating. Just like the polyester/Mylar and Kevlar/Mylar laminates, the Pentex/Mylar laminates are very durable. In terms of both prices and performance, the Pentex falls in between the two. Our feeling is that the Pentex is a better deal than the polyester for club racers and Kevlar (or carbon) is still the ticket for Grand Prix sailors.