Method of making water resistant corrugated boards

1. A method of using a water-based boron-containing suspension as a source of boron additive in a starch-based adhesive, said water-based boron-containing suspension being substantially free of organic solvent(s), said method comprising introducing said water-based boron-containing suspension into a mixing or reaction zone during the preparation of said starch-based adhesive wherein said starch-based adhesive has a waterproofing additive including an aldehyde functionality.

2. The method of claim 1 , wherein said water-based boron-containing suspension comprises:

a) from about 5 wt % to about 60 wt % of at least one boron compound;

b) from about 0.05 wt % to about 10 wt % of at least one suspension aid; and

c) from about 30 wt % to about 95 wt % of water.

3. The method of claim 1 , wherein said water-based boron-containing suspension comprises:

a) from about 5 wt % to about 18 wt % boron;

b) from about 0.5 wt % to about 5 wt % clay; and

c) from about 0.05 wt % to about 1 wt % polysaccharide.

4. The method of claim 3 , wherein said clay is swellable clay.

5. The method of claim 3 , wherein said polysaccharide is xanthan gum.

6. The method of claim 1 , wherein said water-based boron-containing suspension is free of amine-based solvent(s).

7. The method of claim 1 , wherein said suspension has a maximum particle size of no greater than about 50 microns.

8. An aqueous starch-based adhesive, comprising:

a) water;

b) starch;

c) caustic soda; and

d) from about 0.05 wt % to about 10 wt % a water-based boron-containing suspension that is substantially free of organic solvent(s) wherein said starch-based adhesive has a waterproofing additive including an aldehyde functionality.

9. The adhesive of claim 8 , wherein said water-based boron-containing suspension comprises:

a) from about 8 wt % to about 13 wt % boron;

b) from about 0.5 wt % to about 5 wt % clay; and

c) from about 0.05 wt % to about 1 wt % polysaceharide.

10. The adhesive of claim 8 , further comprising a waterproofing additive.

11. The adhesive of claim 10 , wherein said waterproofing additive is a waterproofing resin chosen from ketone-formaldehyde, acetone-formaldehyde, urea-formaldehyde, acetone-urea-formaldehyde, acetone-mclamine-formaldehyde, resorcinol-formaldehyde, polyphenolic resin, or mixtures thereof.

12. The adhesive of claim 8 , wherein said adhesive exhibits wet pin bond strength of at least about 5 lbf according to TAPPI T-821 test method.

13. The adhesive of claim 8 , wherein said adhesive exhibits wet bond strength characterized by percentage fiber tear of at least about 50% estimated after wet pin bond strength test.

14. The adhesive of claim 8 , wherein said adhesive exhibits a dry pin bond strength of at least about 50 lbf according to TAPPI T-821 test method.

15. A method of making starch-based adhesive of claim 8 , comprising adding a water-based boron-containing suspension as a source of boron additive into a mixing zone or reaction zone during the preparation of said starch-based adhesive, said water-based boron-containing suspension being substantially free of organic solvent(s).

16. A method of making a corrugated board, comprising

corrugating a sheet to create a medium bearing fluted tips having a first side and a second side;

applying a starch-based adhesive of claim 8 to the first side of said fluted tips of said medium to create a first adhesive bearing surface; and

bringing a first liner substrate in contact with said first adhesive bearing surface.

17. The method of claim 16 , wherein said sheet is a laminate composed of at least two sheets bonded with an adhesive.

18. The method of claim 17 , wherein said adhesive is the starch-based adhesive of claim 8 .

19. The method of claim 16 , further comprising applying an adhesive to the second side of the fluted tips of the medium to create a second adhesive bearing surface; and bringing a second liner substrate in contact with said second adhesive bearing surface.

20. A corrugated board prepared according to the method of claim 16 , comprising

a) a fluted medium bearing fluted tips having a first side and a second side,

b) a first liner substrate, and

c) a said starch based adhesive of claim 8 sandwiched between the first side of said fluted tips of the medium and said first liner substrate.

21. The corrugated board of claim 20 , further comprising a second liner substrate and an adhesive sandwiched between the second side of said fluted tips of the medium and said second liner substrate.

22. A laminate comprising a first substrate having a first surface and a second surface; a second substrate having a first surface and a second surface; and a starch-based adhesive of claim 8 sandwiched between said first surface of said first substrate and said first surface of said second substrate, said laminate being prepared by applying the starch-based adhesive of claim 8 to said first surface of said first substrate to create a first adhesive bearing surface; and having said first surface of said second substrate in contact with said first adhesive bearing surface.

23. The laminate of claim 22 , wherein said laminate is a fluted medium bearing plural fluted tips having a first side and a second side, said starch-based adhesive being applied to the first side of the fluted tips to create said first adhesive bearing surface.

24. A method of using a water-based boron-containing suspension as a source of boron additive in a starch-based adhesive, said method comprising introducing said water-based boron-containing suspension into a mixing or reaction zone during the preparation of said starch-based adhesive, said starch-based adhesive exhibiting wet bond strength characterized by percentage fiber tear of at least about 50% estimated after wet pin bond strength test wherein said starch-based adhesive has a waterproofing additive including an aldehyde functionality.

25. An article of commerce, comprising a container that contains a water-based boron-containing suspension, said water-based boron-containing suspension being substantially free of organic solvent(s), said container bearing an instruction to use said suspension in a starch-based adhesive wherein said starch-based adhesive has a waterproofing additive including an aldehyde functionality.