US 12,090,432 B2
Filter medium
Joerg Meier, Grossaitingen (DE); and Joerg Lehnert, Schwabmuenchen (DE)
Assigned to Johns Manville, Denver, CO (US)
Filed by JOHNS MANVILLE, Denver, CO (US)
Filed on Dec. 18, 2013, as Appl. No. 14/132,742.
Claims priority of application No. 10 2012 025 023.1 (DE), filed on Dec. 20, 2012.
Prior Publication US 2014/0174934 A1, Jun. 26, 2014
Int. Cl. B01D 39/16 (2006.01); B01D 39/20 (2006.01); D04H 1/485 (2012.01)
CPC B01D 39/1623 (2013.01) [B01D 39/2017 (2013.01); D04H 1/485 (2013.01); B01D 2239/0659 (2013.01); B01D 2239/10 (2013.01); B01D 2239/1233 (2013.01); B01D 2239/1258 (2013.01); B01D 2239/1291 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A filter medium comprising:
a prefabricated first layer, wherein the prefabricated first layer comprises a first spunbonded nonwoven layer comprising synthetic polymer fibres;
wherein the prefabricated first layer has a weight per unit area of 50 to 500 g/m2;
wherein the synthetic polymer fibres of the prefabricated first layer have a linear density in the range of 0.7 to ≤6 dtex;
wherein the synthetic polymer fibres of the prefabricated first layer comprise a polyester;
wherein the prefabricated first layer has no chemical binders;
wherein the prefabricated first layer has an air permeability of 500-2000 l/m2 sec; and
the prefabricated first layer comprises a linen embossing;
a prefabricated second layer which is applied to at least one side of the prefabricated first layer, wherein the prefabricated second layer comprises a second spunbonded nonwoven layer of synthetic polymer fibres;
wherein the prefabricated second layer has a weight per unit area of 50-500 g/m2;
wherein the synthetic polymer fibres of the prefabricated second layer have a linear density in the range of 3.0 to ≤15 dtex;
wherein the synthetic polymer fibres of the prefabricated second layer have a diameter that is at least 10% greater than the synthetic polymer fibres of the prefabricated first layer;
wherein the prefabricated second layer has no chemical binders;
wherein the air permeability of the prefabricated second layer is greater than the air permeability of the prefabricated first layer;
wherein one of the prefabricated first layer and the prefabricated second layer is consolidated using mechanical consolidation but not thermal consolidation and the other of the prefabricated first layer and the prefabricated second layer is thermally consolidated;
wherein fibres of one or both of the prefabricated first layer and the prefabricated second layer comprise an antimicrobial finish;
wherein the prefabricated first layer and the prefabricated second layer are coupled together by using mechanical needling of 20 to 100 punches per cm2 using punches that produce holes having diameters in the prefabricated first and second layers; and
wherein at least some of the holes formed on an outer side of the prefabricated first layer that faces away from the prefabricated second layer by the mechanical needling are fully closed.