THERMOPLASTIC-IMPREGNATED CELLULOSIC NONWOVEN AS A COMPOSTABLE FILTER MATERIAL FOR LIQUIDS

1 . Compostable filter material for liquids,

wherein the filter material is a heat sealable thermoplastic-impregnated cellulosic nonwoven, the filter material having a Textest Air Permeability of 50 to 1000 L/m 2 ·s at 196 Pa, measured according to ISO 9237.

2 . Compostable filter material according to claim 1 ,

wherein the filter material has a pore size distribution including smallest pores with a minimum pore size and largest pores with a maximum pore size, wherein the mean pore size of the filter material is of from 10 to 60 μm.

3 . Compostable filter material according to claim 2 , wherein the largest pores have a maximum pore size of at least 50 μm.

4 . Compostable filter material according to claim 3 , wherein the smallest pores have a minimum pore size of from 1 to 30 μm.

5 . Compostable filter material according to any of claims 1 to 4 ,

wherein the thermoplastic-impregnated cellulosic nonwoven comprises a cellulosic nonwoven material and at least one thermoplastic binder, the cellulosic nonwoven material comprising cellulose-based fibers.

6 . Compostable filter material according to claim 5 ,

wherein the amount of thermoplastic binder is of from 10 to 75 wt %, based on the total weight of the thermoplastic-impregnated cellulosic nonwoven, and/or

wherein the thermoplastic binder is a compostable binder.

7 . Compostable filter material according to claim 6 ,

wherein the amount of the cellulose based fibers in the cellulosic nonwoven material is 90 wt % or more, based on the total weight of the cellulosic nonwoven material; and/or

wherein the cellulose based fibers are natural cellulosic fibers or man-made cellulosic fibers or a mixture of both, the cellulose based fibers preferably being a mixture having a ratio of natural cellulosic fibers to man-made cellulosic fibers of from 7:3 to 9:0.5; and/or

wherein the thermoplastic binder is one or more selected from the group consisting of polyurethane, polybutylene succinate and polylactic acid, preferably wherein the thermoplastic binder is polyurethane.

8 . Compostable filter material according to claim 1 ,

wherein the thermoplastic-impregnated cellulosic nonwoven has a basis weight of at least 15 g/m 2 ; and/or

wherein the thermoplastic-impregnated cellulosic nonwoven has a thickness of at least 60 μm; and/or

wherein the thermoplastic-impregnated cellulosic nonwoven has a mean flow pore diameter of between 10 and 50 μm.

9 . Compostable packaging element, comprising the compostable filter material according to claim 1 .

10 . Compostable packaging element of claim 9 , wherein the compostable packaging element is a coffee capsule, a coffee capsule lid, or a tea bag.

11 . Compostable packaging element according to claim 10 , wherein the compostable packaging element is a coffee capsule lid, the lid further comprising a cellulosic support layer.

12 . Method for producing a compostable filter material as defined in claim 1 , the method comprising:

i) providing a cellulosic nonwoven;

ii) impregnating the cellulosic nonwoven with a thermoplastic binder.

13 . Use of a compostable filter as defined in claim 1 in a method for producing coffee.

14 . Compostable filter material according to claim 6 , wherein the thermoplastic binder is a home compostable binder.

15 . Compostable filter material according to claim 1 , wherein the thermoplastic-impregnated cellulosic nonwoven has a basis weight between 20 and 90 g/m 2 , and/or wherein the thermoplastic-impregnated cellulosic nonwoven has a thickness between 80 and 150 μm.

16 . Compostable filter material according to claim 2 , wherein the largest pores have a minimum pore size of from 50 to 120 μm.