Binders containing an aldehyde-based resin and an isocyanate-based resin and methods for making composite lignocellulose products therefrom
Binders, methods for making same, and methods for making composite lignocellulose products therefrom. The binder can include about 30 wt % to about 40 wt % of solids that include a urea-modified aldehyde-based resin; about 0.1 wt % to about 3 wt % of solids that include an isocyanate-based resin; about 0.1 wt % to about 12 wt % of an extender; and about 50 wt % to about 62 wt % of water, where all weight percent values are based on a total weight of the binder. The binder can have a sodium hydroxide equivalent weight alkalinity of about 3 wt % to about 9 wt %.
1. A binder for making composite lignocellulose products, comprising:
about 32 wt % to about 38 wt % of solids comprising a urea-modified aldehyde-based resin, wherein the urea-modified aldehyde-based resin comprises a urea-modified phenol-formaldehyde resin having a formaldehyde to phenol molar ratio of about 1.8:1 to about 2.6:1;
about 1 wt % to about 2 wt % of solids comprising an isocyanate-based resin;
about 2.9 wt % to about 5.2 wt % of an extender; and
about 53 wt % to about 58 wt % of a liquid medium, wherein the binder comprises 4 wt % to about 9.5 wt % of free urea, mono-methylol urea, di-methylol urea, tri-methylol urea, urea covalently bonded with a carbon atom derived from an aldehyde during synthesis of the urea-modified aldehyde-based resin, or a mixture thereof, wherein all weight percent values are based on a total weight of the binder, wherein the binder has a sodium hydroxide equivalent weight alkalinity of about 4.5 wt % to about 7.5 wt %, and wherein the binder is free of a surfactant.
2. The binder of claim 1 , wherein at least a portion of urea in the urea-modified aldehyde-based resin is in the form of free urea, mono-methylol urea, di-methylol urea, or tri-methylol urea, or a mixture thereof.
3. The binder of claim 1 , wherein at least a portion of urea in the urea-modified aldehyde-based resin is covalently bonded with a carbon atom derived from an aldehyde during synthesis of the urea-modified aldehyde-based resin.
4. The binder of claim 1 , wherein the urea-modified aldehyde-based resin further comprises a urea-modified melamine-formaldehyde resin, a urea-modified phenol-melamine-formaldehyde resin, a urea-modified resorcinol-formaldehyde resin, a urea-modified phenol-resorcinol-formaldehyde resin, or any mixture thereof.
5. The binder of claim 1 , wherein the binder comprises sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, calcium carbonate, sodium borate, potassium borate, calcium borate, and zinc borate or a mixture thereof.
6. The binder of claim 1 , wherein the binder has a viscosity of ≤8,500 cP when maintained at a temperature of about 25° C. for at least 8 days after formation of the binder.
7. The binder of claim 1 , further comprising about 0.1 wt % to about 12 wt % of a filler, based on the total weight of the binder.
8. The binder of claim 7 , wherein the extender comprises wheat flour, corn flour, or a mixture thereof, and wherein the filler comprises corn cob residue, a nutshell flour, a fruit pit flour, or a mixture thereof.
9. A binder for making composite lignocellulose products, comprising:
about 32 wt % to about 38 wt % of solids comprising a urea-modified aldehyde-based resin, wherein the urea-modified aldehyde-based resin comprises a urea-modified phenol-formaldehyde resin having a formaldehyde to phenol molar ratio of about 1.8:1 to about 2.6:1;
about 1 wt % to about 2 wt % of solids comprising an isocyanate-based resin;
about 2.9 wt % to about 5.2 wt % of an extender;
about 0.01 wt % to about 0.5 wt % of a surfactant, wherein the surfactant comprises an acetylenic diol compound, ethylene glycol, or a mixture thereof; and
about 53 wt % to about 58 wt % of a liquid medium, wherein the binder comprises 4 wt % to about 9.5 wt % of free urea, mono-methylol urea, di-methylol urea, tri-methylol urea, urea covalently bonded with a carbon atom derived from an aldehyde during synthesis of the urea-modified aldehyde-based resin, or a mixture thereof, wherein all weight percent values are based on a total weight of the binder, and wherein the binder has a sodium hydroxide equivalent weight alkalinity of about 4.5 wt % to about 7.5 wt %.
10. The binder of claim 1 , further comprising about 0.05 wt % to about 3.5 wt % of a salt, based on the total weight of the binder, and wherein the salt comprises sodium chloride, potassium chloride, calcium chloride, sodium sulfate, potassium sulfate, calcium sulfate, magnesium sulfate, or a mixture thereof.
11. The binder of claim 1 , wherein the liquid medium comprises water.
12. The binder of claim 1 , further comprising about 0.1 wt % to about 12 wt % of a filler, based on the total weight of the binder, wherein at least a portion of the urea in the urea-modified phenol-formaldehyde resin is covalently bonded with a carbon atom derived from an aldehyde during synthesis of the urea-modified aldehyde-based resin, and at least a portion of the urea in the urea-modified phenol-formaldehyde resin is in the form of mono-methylol urea, in the form of di-methylol urea, or in the form of tri-methylol urea.
13. The binder of claim 1 , wherein:
a first portion of urea in the urea-modified aldehyde-based resin is covalently bonded with a carbon atom derived from an aldehyde during synthesis of the urea-modified aldehyde-based resin by adding the first portion of urea as a reactant during the synthesis of the urea-modified aldehyde-based resin, and
a second portion of urea in the urea-modified phenol-aldehyde resin is in the form of free urea added after the urea-modified aldehyde-based resin is synthesized.
14. The binder of claim 13 , wherein:
an amount of the first portion of urea added during the synthesis of the urea-modified aldehyde resin is at least 2 wt %, based on the total weight of the binder, and
an amount of the second portion of urea added after the urea-modified aldehyde-based resin is synthesized is at least 2 wt %, based on the total weight of the binder.
15. The binder of claim 1 , wherein the binder comprises 6 wt % to about 7.5 wt % of free urea, mono-methylol urea, di-methylol urea, tri-methylol urea, urea covalently bonded with a carbon atom derived from an aldehyde during synthesis of the urea-modified aldehyde-based resin, or a mixture thereof, based on the total weight of the binder.
16. A method for making a composite product, comprising:
combining a plurality of lignocellulose substrates and a binder to produce a resinated furnish, wherein the binder comprises:
about 32 wt % to about 38 wt % of solids comprising a urea-modified aldehyde-based resin, wherein the urea-modified aldehyde-based resin comprises a urea-modified phenol-formaldehyde resin having a formaldehyde to phenol molar ratio of about 1.8:1 to about 2.6:1;
about 1 wt % to about 2 wt % of solids comprising an isocyanate-based resin;
about 2.9 wt % to about 5.2 wt % of an extender; and
about 53 wt % to about 58 wt % of a liquid medium, wherein the binder comprises 4 wt % to about 9.5 wt % of free urea, mono-methylol urea, di-methylol urea, tri-methylol urea, urea covalently bonded with a carbon atom derived from an aldehyde during synthesis of the urea-modified aldehyde-based resin, or a mixture thereof, wherein all weight percent values are based on a total weight of the binder, wherein the binder has a sodium hydroxide equivalent weight alkalinity of about 4.5 wt % to about 7.5 wt %, and wherein the binder is free of a surfactant; and
heating the resinated furnish to a temperature of about 60° C. to about 300° C. to at least partially cure the binder to produce a composite lignocellulose product.