Methods for making lignocellulose composite products

1. A method for making a lignocellulose composite product, comprising:

combining a plurality of lignocellulose substrates, calcium lignosulfonate, and a free radical precursor to produce a mixture, wherein the free radical precursor comprises an oxidant and a catalyst; and

at least partially curing the mixture to produce the lignocellulose composite product.

2. The method of claim 1 , wherein the lignocellulose composite product has a brightness of about 15% to about 25%, as measured according to according to TAPPI Test Method T 452 at a wavelength of 457 nm.

3. The method of claim 1 , wherein a brightness of the lignocellulose composite product is greater than a brightness of a lignocellulose composite product made under the same conditions with ammonium lignosulfonate instead of calcium lignosulfonate, as measured according to TAPPI Test Method T 452 at a wavelength of 457 nm.

4. The method of claim 1 , wherein a brightness of the lignocellulose composite product is at least 1.1 times greater than a brightness of a lignocellulose composite product made under the same conditions with ammonium lignosulfonate instead of calcium lignosulfonate, as measured according to TAPPI Test Method T 452 at a wavelength of 457 nm.

5. The method of claim 1 , wherein a brightness of the lignocellulose composite product is at least 1.5 times greater than a brightness of a lignocellulose composite product made under the same conditions with ammonium lignosulfonate instead of calcium lignosulfonate, as measured according to TAPPI Test Method T 452 at a wavelength of 457 nm.

6. The method of claim 1 , wherein the mixture comprises about 0.05 wt % to about 5 wt % of the catalyst based on a dry weight of the plurality of lignocellulose substrates.

7. The method of claim 1 , wherein the catalyst comprises potassium ferricyanide, iron ethylenediaminetetraacetic acid, iron (S,S)-ethylenediamine-N,N′-disuccinic acid, iron diethylenetriamine pentaacetic acid, iron ethlyleneglycol bis(2-aminoethyleter)-N, N,N′,N′-tetraacetic acid, iron trans-1,2-diaminocyclohexanetetraacetic acid, or any mixture thereof.

8. The method of claim 1 , wherein the oxidant comprises hydrogen peroxide, and wherein the catalyst comprises iron.

9. The method of claim 1 , wherein the catalyst is in the form of a complex bound to one or more complexing agents.

10. The method of claim 9 , wherein the one or more complexing agents comprises cyanide (CN − ), sulfate (SO 4 2− ), ethylenediaminetetraacetic acid (EDTA), ethylenediamine-N,N′-disuccinic acid (EDDS), ethyleneglycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA), diethylenetriaminepentaacetic acid (DTPA), trans-1,2-diaminocyclohexane tetraacetic acid (CDTA), iminodisuccinate (IDS), nitrilotracetic acid (NTA), isomers thereof, acids thereof, salts thereof, hydrates thereof, or any mixture thereof.

11. The method of claim 1 , further comprising:

maintaining the mixture at a temperature of less than 60° C. for at least 10 minutes while retaining at least 11 wt % of the oxidant charged to the mixture; and then

heating the mixture comprising at least 11 wt % of the oxidant charged to the mixture to a temperature of at least 60° C. to about 300° C. to produce the lignocellulose composite product.

12. The method of claim 11 , wherein the mixture is maintained at the temperature of less than 60° C. for at least 20 minutes while retaining at least 25 wt % of the oxidant charged to the mixture, and wherein the mixture comprising at least 25 wt % of the oxidant charged to the mixture is heated to the temperature of at least 60° C. to about 300° C. to produce the lignocellulose composite product.

13. The method of claim 11 , wherein, prior to heating the mixture comprising at least 11 wt % of the oxidant charged to the mixture to the temperature of at least 60° C. to about 300° C. to produce the lignocellulose composite product, an amount of energy generated from the mixture due to any exothermic reaction is less than 20 cal/g.

14. The method of claim 1 , wherein the calcium lignosulfonate is in a solid form when combined with the plurality of lignocellulose substrates and the free radical precursor.

15. The method of claim 1 , wherein the calcium lignosulfonate is in a liquid form when combined with the plurality of lignocellulose substrates and the free radical precursor.

16. A method for making a lignocellulose composite product, comprising:

combining a plurality of lignocellulose substrates, calcium lignosulfonate, a free radical precursor, and a polyphenolic material, an unsaturated compound, or both a polyphenolic material and an unsaturated compound to produce a mixture, wherein the unsaturated compound comprises two or more unsaturated carbon-carbon bonds, wherein at least one of the unsaturated carbon-carbon bonds is a pi-bond that is not conjugated with an aromatic moiety and is capable of free radical addition, and wherein the polyphenolic material comprises lignin, tannins, a novolac resin, bisphenol A, modified phenol formaldehyde resin, humic acid, or any mixture thereof, and wherein the free radical precursor comprises an oxidant and a catalyst; and

at least partially curing the mixture to produce the lignocellulose composite product.

17. The method of claim 16 , wherein the mixture comprises the unsaturated compound, and wherein the unsaturated compound comprises dicyclopentadiene (DCPD), ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, poly(ethylene glycol) diacrylate, poly(ethylene glycol) dimethacrylate, trimethylolpropane triacrylate (TMPTA), pentaerythritol tetraacrylate, pentaerythritol triacrylate, polyacrylate starch, linseed oil, an unsaturated prepolymer, or any mixture thereof.

18. The method of claim 16 , wherein at least partially curing the mixture comprises heating the mixture comprising at least 11 wt % of the oxidant charged to the mixture to a temperature of at least 60° C. to about 300° C. to produce a composite product.

19. The method of claim 18 , wherein the mixture is maintained at a temperature of less than 60° C. for at least 10 minutes prior to heating the mixture comprising at least 11 wt % of the oxidant charged to the mixture to the temperature of at least 60° C. to about 300° C.

20. A method for making a lignocellulose composite product, comprising:

combining a plurality of lignocellulose substrates, calcium lignosulfonate, a free radical precursor, and an unsaturated compound to produce a mixture, wherein:

the free radical precursor comprises an oxidant and a catalyst,

the unsaturated compound comprises dicyclopentadiene (DCPD), ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, poly(ethylene glycol) diacrylate, poly(ethylene glycol) dimethacrylate, trimethylolpropane triacrylate (TMPTA), pentaerythritol tetraacrylate, pentaerythritol triacrylate, an unsaturated polyester prepolymer, an unsaturated polyether prepolymer, an unsaturated polyamide prepolymer, an unsaturated polyurethane prepolymer, or any mixture thereof, and

the mixture comprises about 1 wt % to 80 wt % of the unsaturated compound, based on a combined weight of the unsaturated compound and the free radical precursor; and

at least partially curing the mixture to produce the lignocellulose composite product.