Patent ID: 7892633
Filing Date: 2011-02-22
Classification: B29K,B32B,H01Q,H05K,Y10T

Abstract:
1. A method comprising: i) providing an electromagnetic wave at a frequency between about 100 kHz and about 100 GHz; ii) placing a laminate structure in the path of the electromagnetic wave, the laminate structure comprising a fabric layer comprising a plurality of semi-crystalline multi-filament polypropylene fibers having a modulus greater than about 8 GPa and exhibiting at least one of the following characteristics: a) a tenacity greater than 400 MPa, b) greater than 80% crystallinity according to WAXS measuring techniques, and c) a ratio of equatorial intensity to meridonal intensity of greater than 1.0 as measured by SAXS techniques, wherein the laminate structure is essentially transparent to electromagnetic energy and exhibits a dielectric constant of less than about 3.5; wherein said polypropylene fibers alone exhibit a dielectric constant of less than about 3.5, and wherein said polypropylene fibers further exhibit a capability to impart a flexural strength of at least 80 MPa to a laminate structure of eight fabric layers consisting of said polypropylene fibers as the only fibers present; and iii) passing the electromagnetic wave through the laminate structure.