Carbohydrate binders and materials made therewith
A binder comprising a polymeric binder comprising the products of a carbohydrate reactant and nucleophile is disclosed. The binder is useful for consolidating loosely assembled matter, such as fibers. Fibrous products comprising fibers in contact with a carbohydrate reactant and a nucleophile are also disclosed. The binder composition may be cured to yield a fibrous product comprising fibers bound by a cross-linked polymer. Further disclosed are methods for binding fibers with the carbohydrate reactant and polyamine based binder.
1. A method of making a composite wood board comprising a collection of matter comprising cellulosic fibers bound with a cured thermoset polymeric binder, the method comprising:
(i) preparing an aqueous binder solution containing reactants for producing the cured thermoset polymeric binder, wherein the reactants include a reducing sugar and a nucleophile R 1 -Q-R 2 , wherein;
Q is alkyl, cycloalkyl, heteroalkyl, or cycloheteroalkyl, each of which is optionally substituted,
R 1 is selected from the group consisting of an amine, an azide, a cyanate, an isocyanate, a thiol, a disulfide, a thiocyanate, a halogen, a haloformyl, a carboxyl, a carboxylate, a hydroxyl, and an alkoxide, and
R 2 is selected from the group consisting of an amine, an amide, an imine, an imide, a nitro, a nitrate, a pyridine, a phosphate, a phosphono, a hydroxyl, a sulphono, a sulpho, a sulfinyl, and a sulfhydryl,
provided that when the nucleophile consists of polyethylenimine, the mole ratio of the reducing sugar to the nucleophile is in the range of 1:1 to 30:1;
(ii) disposing the aqueous binder solution onto a collection of matter;
(iii) drying the aqueous binder solution to form an uncured product; and
(iv) thermally curing the uncured product which comprises 3% to 25% of dry binder solids (total uncured solids by weight) to form the composite wood board bound with the cured thermoset polymeric binder.
2. The method of claim 1 , wherein preparing the aqueous binder solution includes at least one of the steps selected from the group consisting of:
a) adding an amount of the reducing sugar and an amount of the nucleophile so a weight ratio of the reducing sugar to the nucleophile is in the range of about 2:1 to about 10:1;
b) adding the reducing sugar and the nucleophile to an aqueous solution; and
c) adjusting the pH of the solution to within the range of about 8 to about 12.
3. The method of claim 1 , in which the cured thermoset polymeric binder is formaldehyde free.
4. The method of claim 1 , in which neither formaldehyde nor phenol is used as a reagent.
5. The method of claim 1 , wherein the cellulosic fibers comprises matter selected from the group consisting of wood shavings, sawdust, wood pulp, ground wood, jute, flax, hemp and straw.
6. The method of claim 1 , wherein the weight ratio of the reducing sugar to the nucleophile is in the range of 2:1 to 10:1.
7. The method of claim 1 , wherein the reducing sugar is selected from the group consisting of dextrose, xylose, fructose, dihydroxyacetone, and mixtures thereof.
8. The method of claim 1 , wherein R 1 and R 2 form covalent bonds with the reducing sugar to form the polymeric binder.
9. The method of claim 1 , wherein
R 1 is selected from the group consisting of an azide, a cyanate, an isocyanate, a thiol, a disulfide, a thiocyanate, a halogen, a haloformyl, a carboxyl, a carboxylate, a hydroxyl, and an alkoxide, and
R 2 is selected from the group consisting of an amine, an amide, an imine, an imide, a nitro, a nitrate, a pyridine, a phosphate, a phosphono, a hydroxyl, a sulphono, a sulpho, a sulfinyl, and a sulfhydryl.
10. The method of claim 1 , wherein
R 1 is selected from the group consisting of an amine, an azide, a cyanate, an isocyanate, a thiol, a disulfide, a thiocyanate, a halogen, a haloformyl, a carboxyl, a carboxylate, a hydroxyl, and an alkoxide, and
R 2 is a selected from the group consisting of an amide, an imine, an imide, a nitro, a nitrate, a pyridine, a phosphate, a phosphono, a hydroxyl, a sulphono, a sulpho, a sulfinyl, and a sulfhydryl.
11. The method of claim 1 , wherein
R 1 is selected from the group consisting of an azide, a thiol, a halogen, a carboxyl, a carboxylate, a hydroxyl, and an alkoxide, and
R 2 is a selected from the group consisting of an imine, a pyridine, a phosphate, a phosphono, a hydroxyl, a sulfinyl, and a sulfhydryl.
12. The method of claim 1 , wherein R 1 -Q-R 2 does not consist of polyethylenimine.
13. The method of claim 1 , wherein neither R 1 nor R 2 is an amine.
14. The method of claim 1 , wherein R 1 -Q-R 2 is a primary amine having only one primary amine group.
15. The method of claim 1 , wherein Q is an alkyl selected from the group consisting of C 2 -C 24 .
16. The method of claim 1 , wherein Q is an alkyl selected from the group consisting of C 2 -C 8 .
17. The method of claim 1 , wherein Q is an alkyl selected from the group consisting of C 3 -C 7 .
18. The method of claim 1 , wherein Q is a C 6 alkyl.
19. The method of claim 1 , wherein Q is a cycloalkyl selected from the group consisting of a cyclohexyl, cyclopentyl and cyclobutyl.
20. The method of claim 1 , wherein R 1 -Q-R 2 is 2-[(2-aminoethyl)amino]ethanol.
21. The method of claim 1 , wherein each of R 1 and R 2 is thiol.
22. The method of claim 1 , wherein R 1 is an amine and R 2 is an amine, an amide, an imine, or an imide.
23. The method of claim 1 , wherein R 1 is an amine and R 2 is an amine.
24. The method of claim 1 , wherein the mole ratio of the reducing sugar to the nucleophile is in the range of 1:1 to 30:1.
25. The method of claim 1 , wherein the mole ratio of the reducing sugar to the nucleophile is in the range of 2:1 to 10:1.
26. The method of claim 1 , wherein the mole ratio of the reducing sugar to nucleophile is in the range of 3:1 to 6:1.
27. The method of claim 1 , wherein preparing the aqueous binder solution includes adjusting the pH of the aqueous binder solution to within the range of 8 to 12.
28. The method of claim 1 , wherein the aqueous binder solution has an alkaline pH.
29. The method of claim 1 , wherein the cured thermoset polymeric binder is water insoluble.
30. The method of claim 1 , wherein the cured thermoset polymeric binder strongly absorbs light at 420 nm.
31. The method of claim 1 , wherein the aqueous binder solution is acid-free.
32. The method of claim 1 , wherein the collection of matter and the cured thermoset polymeric binder further comprises a material selected from the group consisting of a silicon-containing compound, gamma-aminopropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane, aminoethylaminopropyltrimethoxysilane, an aminofunctional oligomeric siloxane and mixtures thereof.
33. The method of claim 1 , wherein the collection of matter and the cured thermoset polymeric binder further comprises a corrosion inhibitor selected from the group consisting of dedusting oil, monoammonium phosphate, sodium metasilicate pentahydrate, melamine, tin (II)oxalate, and a methylhydrogen silicone fluid emulsion.
34. The method of claim 1 , wherein the binder further comprises a non-aqueous moisturizer.