Material for the fabrication of sails

Abstract

An improved reinforced laminate for use in sails or other flexible sheet or membrane applications utilizes a pull-truded thin lightweight reinforcing sheet of unidirectional extruded monofilaments in which the reinforcing sheet or sheets form one or more uni-tapes laminated to a polymer film such as Mylar, or other extended sheet of material. The monofilaments are uniformly embedded in the uni-tape via an elastomeric polymer matrix, with the reinforcing sheet, when incorporated into sails via lamination resulting in sails with reinforcing monofilaments having diameters 5 times less than conventional strands or threads. The use of small diameter monofilaments greatly increases the monofilament-over-monofilament crossover density, resulting in a dramatic increase in shear strength, and Youngs' Modulus, with an accompanying dramatic decrease in weight. In one embodiment the improvement in specific modulus over conventional sail laminates is about six-fold. For example, at only one-third the weight, stretch resistance is two times better. In a preferred embodiment, autoclaving is used in the lamination process to rid the laminate of voids which dramatically reduce shear strength by as much as 30 percent. Alternative void-free laminating processes include a silicone interliner/heated platen technique.