Patent ID: 6355079
Filing Date: 2002-03-12
Classification: B01D,B32B,Y10S

Abstract:
A method for producing a filtering material, said method comprising the steps of forming by a dry forming technique at least one filtering layer (15) of natural fibers and/or plastic fibers and binder material and/or binder fibers and bonding the filtering layer by heat, characterized in that said method also comprises the steps wherein at least one strengthening layer (16,17) is formed by a dry forming technique, said layer being formed so as to be in contact with said at least one filtering layer (15) and in connection with the forming stage of the filtering layer, said strengthening layer being formed of natural fibers and/or plastic fibers and binder material and/or binder fibers and said at least one strengthening layer (16,17) is bonded with said at least one filtering layer (15) in order to form a unity (14), said unity being formed in connection with the heat bonding of the filtering layer, wherein the filter layer has a density of 30-700 g/m2 and the strengthening layer has a density of 5-150 g/m2.