Patent ID: 8187418
Filing Date: 2012-05-29
Classification: D21F,D21H,Y10T

Abstract:
1. A method of making a multilayer fibrous nonwoven mat comprising forming a first slurry containing fibers, forming a second slurry containing fibers and/or particles, feeding the first slurry to a manifold on a forming box, feeding the second slurry to a second manifold on the same forming box, feeding the two slurries inside the forming box to a moving forming wire, the two slurries separated from each other for a portion of the distance from a back wall of the forming box to the forming wire with a flexible lamella, the lamella ending a distance before reaching the forming wire sufficient to allow some mixing of the first slurry and the second slurry before the slurry mixture reaches the forming wire, forming a first layer on the moving forming wire from the first slurry, forming a transition zone on top of the first layer from a mixture of the two slurries, forming a second layer on top of the transition zone from the second slurry to form a wet multilayer web or mat, transferring the wet multilayer web to a second moving screen, and drying the multilayer mat to form a multilayer mat containing a transition zone having a thickness in the range of about 2 to about 10 percent of the thickness of the dry multilayer mat.