Patent ID: 8268391

Claim:
A method for manufacturing a protective coating composition containing nano-cellulose particles comprising the following steps: (a) pretreating cellulose with a sodium hypochlorite solution having pH in the range of 8 to 11 thus obtaining a pretreated cellulose; (b) hydrolyzing the pretreated cellulose with a boiling mineral acid having a concentration of 10 to 30 wt. % thus obtaining an acidic wet cake that contains agglomerates of nano-cellulose particles and a residual mineral acid; (c) introducing at least one precipitator into the obtained acidic wet cake containing agglomerates of nano-cellulose particles, the precipitator forming with the residual mineral acid water-insoluble processing aids that precipitate into the acidic wet cake and reducing acidity of the acidic wet cake to the pH range of 7 to 8; (d) admixing the wet cake, which contains the agglomerates of the nano-cellulose particles and water-insoluble processing aids, with a solution containing a hydrophobic biodegradable polymer, additives of a biodegradable plasticizer, and a natural hydrophobizator soluble in organic solvents; and (e) homogenizing the obtained mixture of the wet cake that contains agglomerates of nano-cellulose particles, the water-insoluble processing aids, the solution containing the hydrophobic biodegradable polymer, the additives of biodegradable plasticizer, and the natural hydrophobizator in order to break out agglomerates of nano-particles and to obtain a uniform composition having an average particle size in the range 50 to 300 nm.