Compostable cellulose-based paper for gas barrier in packaging material

1. Compostable cellulose-based paper having an oxygen transmission rate of less than 10 cm 3 /(m 2 ·day), when determined at 23° C. and 50% relative humidity, the compostable cellulose-based paper comprising a continuous cellulosic fiber matrix that comprises native cellulosic fibers and non-fibrous cellulosic material, wherein the content of the non-fibrous cellulosic material in the continuous cellulosic fiber matrix is of from 15 to 50 wt. %.

2. Compostable cellulose-based paper according to claim 1 , wherein the continuous cellulosic fiber matrix is obtainable by:

(i) providing a cellulose fiber base sheet comprising cellulose fibers;

(ii) treating the cellulose fiber base sheet with a gelatinizing agent to give a treated base sheet comprising non-fibrous cellulosic material;

(iii) washing the treated base sheet comprising the non-fibrous cellulosic material to obtain a precursor cellulosic fiber matrix;

(iv) drying the precursor cellulosic fiber matrix to obtain the continuous cellulosic fiber matrix.

3. Compostable cellulose-based paper according to claim 2 , wherein the gelatinizing agent comprises at least one cellulose solvent selected from the group consisting of inorganic acids comprising sulfuric acid and phosphoric acid, Lewis acids comprising ZnCl 2 and Ca(SCN) 2 , inorganic bases comprising NaOH, organic bases comprising N-methylmorpholine N-oxide, and ionic liquids comprising tetraalkylammonium salts.

4. Compostable cellulose-based paper according to claim 3 , wherein the gelatinizing agent is sulfuric acid and/or wherein the sulfuric acid has a concentration of from 63 to 75%.

5. Compostable cellulose-based paper according to claim 2 wherein step (ii) involves contacting the cellulose fiber base sheet with the gelatinizing agent for at least 60 seconds.

6. Compostable cellulose-based paper according to claim 2 , wherein the washing in step (iii) is carried out with water.

7. Compostable cellulose-based paper according to claim 2 , wherein the cellulose fibers are selected from wood pulp fibers, non-wood vegetable fibers and regenerated cellulose fibers.

8. Compostable cellulose-based paper according to claim 1 , wherein the compostable cellulose-based paper has

a wet burst strength of 150 kPa or more, and

a dry burst strength of 200 kPa or more.

9. Compostable cellulose-based paper according to claim 1 , wherein the compostable cellulose-based paper has a basis weight of 200 g/m 2 or less and/or a thickness of from 30 μm to 250 μm.

10. Compostable cellulose-based paper according to claim 1 , wherein the continuous cellulosic fiber matrix comprises of from 15 to 40 wt. % of the non-fibrous cellulosic material.

11. Compostable cellulose-based paper according to claim 1 , wherein the oxygen transmission rate of the compostable cellulose-based paper is less than 2 cm 3 /(m 2 ·day), when determined at 23° C. and 50% relative humidity.

12. Packaging material for oxygen sensitive products comprising the compostable cellulose-based paper according to claim 1 .

13. Packaging material according to claim 12 , which is selected from the group consisting of butter wrapping, beverage container, coffee capsule, coffee pad, chocolate packaging and biscuit packaging.

14. Packaging material according to claim 12 , wherein the packaging material is a multi-layer product comprising the compostable cellulose-based paper as a first material layer and at least one additional material layer, wherein the at least one additional material layer is laminated on a surface of the compostable cellulose-based paper.

15. Packaging material according to claim 14 , wherein the at least one additional material layer is selected from the group consisting of a water vapor barrier layer, an aroma barrier layer, a water-resistant layer, a thermo-sealable layer, a grease-resistant layer and a printable layer.

16. Compostable cellulose-based paper according to claim 2 , wherein the compostable cellulose-based paper has

a wet burst strength of 150 kPa or more, and

a dry burst strength of 200 kPa or more.

17. Compostable cellulose-based paper according to claim 2 , wherein the compostable cellulose-based paper has a basis weight of 200 g/m 2 or less and/or a thickness of from 30 μm to 250 μm; and

wherein the continuous cellulosic fiber matrix comprises of from 15 to 40 wt. % of the non-fibrous cellulosic material.

18. Compostable cellulose-based paper according to claim 2 , wherein the oxygen transmission rate of the compostable cellulose-based paper is less than 2 cm 3 /(m 2 ·day), when determined at 23° C. and 50% relative humidity.

19. Packaging material for oxygen sensitive products comprising the compostable cellulose-based paper according to claim 2 .

20. Packaging material according to claim 19 , which is selected from the group consisting of butter wrapping, beverage container, coffee capsule, coffee pad, chocolate packaging and biscuit packaging; and

wherein the packaging material is a multi-layer product comprising the compostable cellulose-based paper as a first material layer and at least one additional material layer, wherein the at least one additional material layer is laminated on a surface of the compostable cellulose-based paper; and

wherein the at least one additional material layer is selected from the group consisting of a water vapor barrier layer, an aroma barrier layer, a water-resistant layer, a thermo-sealable layer, a grease-resistant layer and a printable layer.