Method utilizing ultrasonically induced cavitation to impregnate porous sheet passing through a resin bath

摘要

A method of impregnating a flexible, porous cellulosic sheet material involves passing the sheet through a low viscosity resin and across the resonant vibrating surface and through a cavitated zone in close proximity to at least one completely immersed ultrasonic wave generator, operating at a frequency and radiated power level effective to provide a combination vibratory pressure on the resin and cavitation effect causing degassing and heating of the resin, followed by passing the impregnated sheet through a drying means.