Method and apparatus for joining paper material

1. A method for joining paper material ( 2 , 3 ) at a first joining region ( 20 ) and a second joining region ( 30 ), comprising the steps of:

roughening the first joining region ( 20 ),

moistening the first joining region ( 20 ) after the roughening step, and

joining the first and second joining region ( 20 , 30 ) between a sonotrode ( 60 ) and an anvil ( 63 ) of an ultrasonic friction welding apparatus ( 6 ) by ultrasonic friction welding, wherein a vibration direction (A) of the sonotrode ( 60 ) is not parallel to a joining force direction (B) of a joining force of the anvil ( 63 ).

2. The method according to claim 1 , wherein the vibration direction (A) is perpendicular to the joining force direction (B).

3. The method according to claim 1 , wherein the method is carried out continuously such that a linear joined connection ( 11 ) is produced on the paper material.

4. The method according to claim 1 , wherein the roughening of the first joining region is carried out in such a way that a roughness in a range of 20 μm between point elevations and depressions and having a uniform profile is achieved.

5. The method according to claim 1 , wherein the roughening of the first joining region and the moistening of the first joining region occur along a same width of the first joining region.

6. The method according to claim 1 , wherein the joining of the first and the second joining regions is carried out completely without additives.

7. The method according to claim 1 , wherein the paper material to be joined is free of plastics material and adhesive.

8. The method according to claim 1 , wherein the step of roughening is carried out by means of ultrasonic vibration.

9. A paper packaging having a connection produced by a method according to claim 1 , wherein, during roughening of individual paper fibers of the first and the second joining regions, the individual paper fibers are released from a paper composite of the paper packaging and brought to a surface of the joining region.

10. The method according to claim 1 , wherein the roughening of the first joining region is carried out in such a way that a roughness in a range of 10 μm between point elevations and depressions is achieved.

11. An apparatus for joining paper material ( 2 , 3 ) at a joining region ( 20 , 30 ) of the paper material, comprising

a roughening apparatus ( 4 ) for roughening the joining region ( 20 , 30 ) of the paper material,

a moistening apparatus ( 5 ) for moistening the joining region ( 20 , 30 ) the moistening apparatus ( 5 ) configured to moisten the joining region ( 20 , 30 ) after the roughening apparatus ( 4 ) roughens the joining region ( 20 , 30 ), and

an ultrasonic friction welding apparatus ( 6 ) comprising a sonotrode ( 60 ) for generating an ultrasonic vibration and an anvil ( 63 ) for generating a joining force, wherein the ultrasonic vibration is directed in a first direction (A) which is not parallel to a force direction (B) of the joining force of the anvil.

12. The apparatus according to claim 11 , wherein the anvil is in the form of a roller or roll.

13. The apparatus according to claim 11 , wherein the roughening apparatus ( 4 ) works by means of ultrasonic vibration.

14. The apparatus according to claim 11 , wherein the roughening apparatus ( 4 ) produces a roughness in a range of 20 μm.

15. The apparatus according to claim 13 , wherein a sonotrode ( 60 ) of the roughening apparatus ( 4 ) is designed to be flat and has a roughened surface.

16. The method according to claim 6 , wherein the joining of the first and the second joining regions is carried out completely without additive plastics materials or adhesives.

17. The apparatus according to claim 11 , wherein the roughening apparatus ( 4 ) produces a roughness in a range of 10 μm.