| 摘要 |
<p>A multilayer filter material is proposed which contains at least one layer (1, 1', 1'', 2, 2', 2'') of an open-pore foam material. In order to achieve a sufficiently high air permeability in such a material but at the same time to prevent continuous large pores or cavities occurring, it is proposed to cover one layer (1, 1', 1'') at least on one side with a further layer (2, 2', 2''), firmly attached to the first, of an open-pore foam material. It is particularly advantageous if a comparatively thin foam layer (2, 2', 2'') of small pore size is joined to a further foam layer (1, 1', 1'') having a greater thickness and larger pores than the first layer. <IMAGE></p> |
