Formaldehyde-free melamine carbohydrate binders for improved fire-resistant fibrous materials
Embodiments of the present technology include a formaldehyde-free binder composition. The composition may include melamine. The composition may also include a reducing sugar. In addition, the binder composition may include a non-carbohydrate aldehyde or ketone. Embodiments may also include a method of making a formaldehyde-free binder composition. The method may include dissolving melamine in an aqueous solution of a reducing sugar. The concentration of the reducing sugar may be 30 wt. % to 70 wt. % of the aqueous solution, which may be at a temperature of 50° C. to 100° C. The method may also include adding a non-carbohydrate aldehyde or ketone to the dissolved melamine in the aqueous solution to form a binder solution. The temperature of the aqueous solution of the dissolved melamine may be 50° C. to 100° C. during the addition of the non-carbohydrate aldehyde or ketone. The method may further include reducing the temperature of the binder solution.
1. A method of making a formaldehyde-free binder composition, the method comprising:
dissolving melamine in an aqueous solution of a reducing sugar, wherein a concentration of the reducing sugar is 30 wt. % to 70 wt. % of the aqueous solution, and the temperature of the aqueous solution is 50° C. to 100° C.;
adding a non-carbohydrate aldehyde or ketone to the dissolved melamine in the aqueous solution to form a binder solution, wherein the temperature of the aqueous solution of the dissolved melamine is 50° C. to 100° C. during the addition of the non-carbohydrate aldehyde or ketone; and
reducing a temperature of the binder solution to about 23° C.
2. The method of claim 1 , wherein the method further comprises maintaining a temperature of the binder solution at 80° C. to 100° C. for about 60 minutes to 120 minutes after adding all of the non-carbohydrate aldehyde or ketone.
3. The method of claim 1 , wherein the method further comprises adding a curing catalyst to the binder solution.
4. The method of claim 3 , wherein the curing catalyst is chosen from a sulfate salt, a phosphate salt, a borate salt, or combinations thereof.
5. The method of claim 3 , wherein the adding of the curing catalyst comprises adding a 10 wt. % aqueous solution of ammonium sulfate, diammonium phosphate, or a combination of ammonium sulfate and diammonium phosphate in a 1:1 mole ratio.
6. The method of claim 3 , wherein a mole ratio of the melamine to the reducing sugar is 1:3 to 1:12.
7. The method of claim 1 , wherein the reducing sugar comprises dextrose.
8. The method of claim 1 , wherein the non-carbohydrate aldehyde or ketone is chosen from acetaldehyde, butyraldehyde, alkoxylated acetaldehyde, glutaric dialdehyde, acetone, methyl ethyl ketone, or pentanedione.
9. The method of claim 1 , wherein the non-carbohydrate aldehyde or ketone comprises glyoxal.
10. The method of claim 9 , wherein a mole ratio of the melamine to the glyoxal is 2:1 to 1:3.