Method for hydrophobizing a cellulose substrate by utilizing a fatty acid halide

Abstract

The present invention relates to a method for hydrophobizing a cellulose substrate (1), which comprising a first side and a second side, which faces away from the first side, the method comprising the steps of: —drying the cellulose substrate to a dry content above 80%, preferably above 85%; —providing a fatty acid halide in spray form; —converting said fatty acid halide in spray form into vaporized fatty acid halide; and —guiding said vaporized fatty acid halide to contact the first side of the cellulose substrate, and at least partially penetrate the cellulose substrate.

1 . A method for hydrophobizing a cellulose substrate, which comprises a first side and a second side facing away from the first side, wherein the method comprises the steps of:
 drying the cellulose substrate to a dry content above 80%;   providing a fatty acid halide in spray form;   converting said fatty acid halide in spray form into vaporized fatty acid halide; and   guiding said vaporized fatty acid halide to contact the first side of the cellulose substrate, and at least partially penetrate the cellulose substrate.   
     
     
         2 . The method according to  claim 1 , further comprising the step of:
 guiding said fatty acid halide to contact the second side of the cellulose substrate, and at least partially penetrate the cellulose substrate.   
     
     
         3 . The method according to  claim 1 , wherein said guiding of the fatty acid halide is performed by vacuum sucking at the second side of the cellulose substrate, such that the vaporized fatty acid penetrates the cellulose substrate in a predetermined direction through the cellulose substrate. 
     
     
         4 . The method according to  claim 1 , wherein said guiding of the vaporized fatty acid halide is performed by vacuum sucking at the first side of the cellulose substrate, such that the vaporized fatty acid is guided along a surface of the first side of the cellulose substrate in a predetermined direction whereby the fatty acid is brought into contact with the cellulose substrate. 
     
     
         5 . The method according to  claim 1 , wherein the dry content of the cellulose substrate is above 90%. 
     
     
         6 . The method according to  claim 1 , wherein the fatty acid comprises an aliphatic chain length of between 10-22 carbon atoms. 
     
     
         7 . The method according to  claim 1 , wherein the fatty acid comprises palmitoyl chloride, C16, stearoyl chloride, C18, or mixtures thereof. 
     
     
         8 . The method according to  claim 1 , wherein the fatty acid to be sprayed is mixed with at least one solvent or a mixture of solvents, wherein the at least one solvent or a mixture of solvents is preferably selected from a group consisting of: acetone, ethyl acetate, and methyl ethyl ketone. 
     
     
         9 . The method according to  claim 8 , wherein the mixture of fatty acid halide and the at least one solvent or a mixture of solvents comprises 0.1-20 wt %. 
     
     
         10 . The method according to  claim 1 , wherein the cellulose substrate is a paper- or paperboard web. 
     
     
         11 . The method according to  claim 10 , wherein the web is a single- or multilayer web. 
     
     
         12 . The method according to  claim 1 , wherein the cellulose substrate comprises a three-dimensional cellulose-based product. 
     
     
         13 . The method according to  claim 1 , further comprising a step of:
 heating the substrate, before, or after, or before and after adding the fatty acid halide.   
     
     
         14 . The method according to  claim 13 , wherein the heating step is performed by IR heating. 
     
     
         15 . The method according to  claim 3 , wherein the vacuum sucking is performed by a vacuum box. 
     
     
         16 . The method according to  claim 1 , wherein the vacuum sucking is performed by a rotating vacuum cylinder. 
     
     
         17 . The method according to  claim 1 , wherein the step of converting said spray form fatty acid halide into vaporized fatty acid halide is performed by IR heating. 
     
     
         18 . A cellulose based product having been treated by the method according to  claim 1 . 
     
     
         19 . The method according to  claim 1 , wherein the dry content of the cellulose substrate is above 85%. 
     
     
         20 . The method according to  claim 8 , wherein the mixture of fatty acid halide and the at least one solvent or a mixture of solvents comprises 0.1-10 wt % solvent.