Adhesive composition including deacetylated chitosan

1. An adhesive composition comprising:

(a) from 3 to 10% by weight of at least one deacetylated chitosan having a deacetylation degree greater than or equal to 75%;

(b) from 0.5 to 5% by weight of at least one organic or inorganic acid;

(c1) from 0.001 to 8% by weight of a polyanionic compound,

(c2) from 0.001 to 2% by weight of a polyol of formula C n H 2n+2 O n , wherein n represents an integer between 2 and 10; and

(d) an additional amount of an aqueous support.

2. The composition according to claim 1 , comprising from 4 to 6% of said at least one deacetylated chitosan, or from 1 to 3% of said at least one organic or inorganic acid, or from 0.01 to 5% of said compound (c1), or from 0.5 to 1.5% of said compound (c2), or total or partial combinations thereof.

3. The composition according to claim 1 , wherein the chitosan has a molar mass ranging from 10,000 to 500,000 g/mol.

4. The composition according to claim 1 , wherein the acid is sulfuric acid in an aqueous solution or an organic acid selected from carboxylic acids in an aqueous solution.

5. The composition according to claim 4 , wherein the carboxylic acid is acetic acid.

6. The composition according to claim 1 , wherein the compound (c1) is selected from hydroxycarboxylic acids, polycarboxylic acids, hydroxypolycarboxylic acids, polysaccharides, salts or mixtures thereof.

7. The composition according to claim 1 , wherein the compound (c1) is selected from citric acid salts or succinic acid salts.

8. The composition according to claim 1 , wherein the compound (c1) is trisodium citrate dehydrate, or the compound (c2) is glycerol or mannitol.

9. The composition according to claim 1 , for which the ratio (a)/(b) ranges from 3/1 to 10/3, or the ratio (a)/(c1) ranges from 1/2 to 200/1, or the ratio (a)/(c2) ranges from 2/1 to 12/1.

10. The composition according to claim 1 , wherein the support (d) is water.

11. The composition according to claim 1 , comprising:

(a) from 3 to 10% by weight of at least one deacetylated chitosan having a deacetylation degree greater than or equal to 75%;

(b) from 0.5 to 5% by weight of at least one organic or inorganic acid;

(c1) from 0.001 to 8% by weight of a polyanionic compound;

(c2) from 0.001 to 2% by weight of a polyol of formula C n H 2n+2 O n wherein n represents an integer between 2 and 10,

(d) an additional amount of an aqueous support, and

(e) from 0.1 to 20% by weight of a polysaccharide filler.

12. An adhesive composition comprising:

(a) from 3 to 10% by weight of at least one de-acetylated chitosan having a deacetylation degree greater than or equal to 75%;

(b) from 0.5 to 5% by weight of at least one organic or inorganic acid;

(c) at least one compound selected from:

(c1) from 0.001 to 8% by weight of a polyanionic compound,

(c2) from 0.001 to 2% by weight of a polyol of formula C n H 2n+2 O n ,

wherein n represents an integer between 2 and 20; and

(d) an additional amount of an aqueous support; and

(e) a polysaccharide filler comprising a starch from cereals.

13. The composition according to claim 12 , comprising from 0.1 to 20% by weight of polysaccharide filler (e).

14. The composition according to claim 12 , for which the ratio (a)/(e) ranges from 1/10 to 1/1.

15. An adhesive composition comprising:

(a) from 3 to 10% by weight of at least one deacetylated chitosan having a deacetylation degree greater than or equal to 75%;

(b) from 0.5 to 5% by weight of at least one organic or inorganic acid;

(c) at least one compound selected from:

(c1) from 0.001 to 8% by weight of a polyanionic compound,

(c2) from 0.001 to 2% by weight of a polyol of formula C n H 2n+2 O n , wherein n represents an integer between 2 and 20; and

(d) an additional amount of an aqueous support,

said adhesive composition having a shear strength ranging from 7 to 100 MPa.

16. The composition according to claim 15 , comprising from 4 to 6% of said at least one deacetylated chitosan, or from 1 to 3% of said at least one organic or inorganic acid, or from 0.01 to 5% of said compound (c1), or from 0.5 to 1.5% of said compound (c2), or total or partial combinations thereof.

17. The composition according to claim 15 , wherein the chitosan has a molar mass ranging from 10,000 to 500,000 g/mol.

18. The composition according to claim 15 , wherein the acid is sulfuric acid in an aqueous solution or an organic acid selected from carboxylic acids in an aqueous solution.

19. The composition according to claim 18 , wherein the carboxylic acid is acetic acid.

20. The composition according to claim 15 , wherein the compound (c1) is selected from hydroxycarboxylic acids, polycarboxylic acids, hydroxypolycarboxylic acids, polysaccharides, salts or mixtures thereof.

21. The composition according to claim 15 , wherein the compound (c1) is selected from citric acid salts or succinic acid salts.

22. The composition according to claim 15 , wherein the compound (c1) is trisodium citrate dehydrate, or the compound (c2) is glycerol or mannitol.

23. The composition according to claim 15 , for which the ratio (a)/(b) ranges from 3/1 to 10/3, or the ratio (a)/(c1) ranges from 1/2 to 200/1, or the ratio (a)/(c2) ranges from 2/1 to 12/1.

24. The composition according to claim 15 , wherein the support (d) is water.