Formaldehyde-free protein-containing binder compositions
One-part thermosetting binder compositions are described that may include soy protein, a first crosslinking compound, and a second crosslinking compound different from the first crosslinking compound. Upon curing, the first and second crosslinking compounds covalently bond to each other and to the soy protein to form a thermoset binder. Also describe are fiber-containing products that include a plurality of fibers and a formaldehyde-free binder. The formaldehyde-free binder is formed from a one-part, thermosetting binder composition that includes soy protein, a first crosslinking compound, and a second crosslinking compound different from the first crosslinking compound. Upon curing, the first and second crosslinking compounds covalently bond to each other and to the soy protein to form a thermoset binder.
1. A one-part thermosetting binder composition comprising:
soy protein;
a first crosslinking compound; and
a second crosslinking compound different from the first crosslinking compound, wherein the second crosslinking compound comprises a polyol or an alkanol amine, and wherein:
upon curing, the first and second crosslinking compounds covalently bond to each other and to the soy protein to form a thermoset binder,
the first crosslinking compound and the second crosslinking compounds are in an aqueous solution, and
the aqueous solution is not an emulsion.
2. The one-part thermosetting binder composition of claim 1 , wherein the first crosslinking compound is a carboxyl-containing compound.
3. The one-part thermosetting binder composition of claim 2 , wherein the carboxyl-containing compound is a polycarboxy polymer.
4. The one-part thermosetting binder composition of claim 2 , wherein the carboxyl-containing compound is derived from an ethylenically unsaturated carboxylic acid.
5. The one-part thermosetting binder composition of claim 4 , wherein the ethylenically unsaturated carboxylic acid is chosen from acrylic acid, methacrylic acid, maleic acid, fumaric acid, methyl maleic acid, itaconic acid, and crotonic acid.
6. The one-part thermosetting binder composition of claim 2 , wherein the carboxyl-containing compound is derived from an ethylenically unsaturated acid anhydride.
7. The one-part thermosetting binder composition of claim 6 , wherein the ethylenically unsaturated acid anhydride is chosen from maleic anhydride, acrylic anhydride, methacrylic anhydride, and itaconic anhydride.
8. The one-part thermosetting binder composition of claim 2 , wherein the carboxyl-containing compound is chosen from polycarboxy homopolymer and a polycarboxy copolymer.
9. The one-part thermosetting binder composition of claim 8 , wherein the polycarboxy copolymer is a copolymer of:
(i) an unsaturated carboxylic acid or unsaturated carboxylic anhydride; and
(ii) a vinyl compound.
10. The one-part thermosetting binder composition of claim 9 , wherein the vinyl compound is chosen from styrene, acrylate, methacrylate, acrylonitrile, and methacrylonitrile.
11. The one-part thermosetting binder composition of claim 1 , wherein the polyol is chosen from glycerol, ethylene glycol, propylene glycol, diethylene glycol, and triethylene glycol.
12. The one-part thermosetting binder composition of claim 1 , wherein the alkanol amine is chosen from ethanol amine, diethanol amine, and triethanol amine.
13. The one-part thermosetting binder composition of claim 1 , wherein the first crosslinking compound comprises a hydroxyl-containing polyhydroxy polymer and the second crosslinking compound comprises at least one carboxyl group.
14. The one-part thermosetting binder composition of claim 1 , wherein the binder composition comprises 60 wt. % to 95 wt. % soy protein.
15. The one-part thermosetting binder composition of claim 1 , wherein the binder composition has a shelf life of 1 month or more.
16. The one-part thermosetting binder composition of claim 1 , wherein the binder composition has a viscosity of 1 to 1000 centipoise at 20° C.
17. A fiber-containing product comprising:
a plurality of fibers; and
a formaldehyde-free binder,
wherein the formaldehyde-free binder is formed from a one-part thermosetting binder composition that comprises:
soy protein; and
an aqueous solution comprising a first crosslinking compound and a second crosslinking compound different from the first crosslinking compound wherein the second crosslinking compound comprises a polyol or an alkanol amine, and wherein:
upon curing, the first and second crosslinking compounds covalently bond to each other and to the soy protein to form a thermoset binder, and
the aqueous solution is not an emulsion.
18. The fiber-containing product of claim 17 , wherein the plurality of fibers is chosen from organic fibers, inorganic fibers, and a combination of organic and inorganic fibers.
19. The fiber-containing product of claim 18 , wherein the inorganic fibers comprise glass fibers or carbon fibers.
20. The fiber-containing product of claim 18 , wherein the organic fibers comprise organic polymer fibers.
21. The fiber-containing product of claim 17 , wherein the plurality of fibers comprise lignocellulosic fibers.
22. The one-part thermosetting binder composition of claim 1 , wherein the first crosslinking compound comprises a solution polymer compound.
23. The one-part thermosetting binder composition of claim 1 , wherein the soy protein comprises soy flour, soy protein concentrate, soy protein isolate, or soy polymer.