Wood products with enhanced resistance to graying and water infiltration and related technology

Patent metadata

Field	Value
Publication number	US-2016369128-A1
Application number	US-201615208408-A
Country	US
Kind code	A1
Filing date	Jul 12, 2016
Priority date	May 30, 2013
Publication date	Dec 22, 2016
Grant date	—

Abstract

A composite wood product in accordance with a particular embodiment of the present technology includes a composite substrate and a sealant disposed within a surface portion of the substrate. The substrate includes wood and a binder. The sealant includes photoresponsive molecules present within the surface portion of the substrate at an average concentration greater than 1000 parts per million. In response to a 120-day exposure at 7 inches separation distance to a UV lamp with a UVA (315-400 nm) output of 13.6 W and a UVB (280-315 nm) output of 3.0 W, a CIELab b* value of the substrate decreases by a first amount, a CIELab b* value of the sealant increases by a second amount, and a CIELab b* value of the overall wood product decreases by an amount less than the first amount, increases by an amount less than the second amount, or is unchanged.

First claim

I/We claim:

1 . A composite wood product, comprising:
a composite substrate including wood and a binder, wherein a CIELab b* value of the substrate decreases by a first amount to a first value in response to a 120-day exposure at 7 inches separation distance to a UV lamp with a UVA (315-400 nm) output of 13.6 W and a UVB (280-315 nm) output of 3.0 W; and a sealant disposed within a surface portion of the substrate, wherein the sealant includes photoresponsive molecules at an average concentration greater than 1000 parts per million in an outermost one millimeter of the substrate, wherein a CIELab b* value of the sealant increases by a second amount to a second value in response to the 120 day exposure at 7 inches separation distance to the UV lamp, and wherein a CIELab b* value of the wood product in response to the 120-day exposure at 7 inches separation distance to the UV lamp is greater than the first value.

2 . The composite wood product of claim 1 wherein the CIELab b* value of the wood product in response to the 120-day exposure at 7 inches separation distance to the UV lamp decreases by an amount less than the first amount.

3 . The composite wood product of claim 1 wherein the CIELab b* value of the wood product in response to the 120-day exposure at 7 inches separation distance to the UV lamp increases by an amount less than the second amount.

4 . The composite wood product of claim 1 wherein the CIELab b* value of the wood product in response to the 120-day exposure at 7 inches separation distance to the UV lamp is unchanged.

5 . The composite wood product of claim 1 wherein:
the first amount is at least 7; and
the second amount is at least 7.

6 . The composite wood product of claim 1 wherein the sealant includes colorizing molecules individually having one or more covalently bound chromophores.

7 . The composite wood product of claim 1 wherein the sealant is a crosslinked urethane resin present within the surface portion of the substrate at an average concentration from 0.05% to 5.0% by weight.

8 . The composite wood product of claim 1 wherein the photoresponsive molecules are substituted aniline molecules.

9 . The composite wood product of claim 1 wherein the photoresponsive molecules are aromatic isocyanate molecules.

10 . The composite wood product of claim 1 wherein the photoresponsive molecules have the same or different respective molecular weights less than 500 daltons.

11 . The composite wood product of claim 1 wherein the photoresponsive molecules form quinone-like molecules in response to all or a portion of the 120-day exposure at 7 inches separation distance to the UV lamp.

12 . A method of making a composite wood product, the method comprising:
applying liquid water to a composite substrate, wherein the substrate includes wood and a binder; applying a penetrating sealant to the substrate after applying the liquid water to the substrate, wherein the sealant includes at least 50% by weight aromatic isocyanate molecules having the same or different respective molecular weights less than 300 daltons; and exposing the substrate and the sealant to an average temperature less than 120° C. over a 24-hour period immediately after applying the sealant to the substrate, wherein at least some of the aromatic isocyanate molecules form photoresponsive molecules during the 24-hour period, and wherein an average concentration of the photoresponsive molecules after the 24-hour period is greater than 1000 parts per million in an outermost one millimeter of the substrate.

13 . The method of claim 12 wherein applying the sealant to the substrate includes applying the sealant to a surface of the substrate at a rate of at least one gram of the sealant per square foot of the surface.

14 . The method of claim 12 wherein the sealant includes methylene diphenyl diisocyanate at a concentration of at least 80% by weight.

15 . The method of claim 12 wherein the sealant includes a first isomer of methylene diphenyl diisocyanate at a concentration of at least 20% by weight, and a second isomer of methylene diphenyl diisocyanate different than the first isomer of methylene diphenyl diisocyanate at a concentration of at least 20% by weight.

16 . The method of claim 12 wherein the average temperature is within a range from 60° F. to 160° F.

17 . The method of claim 12 , further comprising, before applying the sealant to the substrate, reacting aromatic isocyanate molecules within the sealant with molecules of a polyol colorant to form oligomer molecules having covalently bound chromophores.

18 . The method of claim 12 wherein applying liquid water to the substrate includes applying liquid water to a surface of the substrate at a rate of at least one gram of liquid water per square foot of the surface.

19 . The method of claim 12 , further comprising applying liquid water to the substrate after applying the sealant to the substrate.

20 . The method of claim 19 wherein applying liquid water to the substrate after applying the sealant to the substrate includes applying liquid water to a surface of the substrate at a rate of at least one gram of liquid water per square foot of the surface.

Assignees

• Weyerhaeuser Nr Co

Inventors

• Winterowd Jack G
• Parker Erik M
• Robak Glen D
• Smith Jeffrey
• Brady William D

Classifications

• C08G18/7671

  containing only one alkylene bisphenyl group · CPC title

• B27K2200/30

  Multilayer articles comprising wood · CPC title

• Y10T428/31591

  Next to cellulosic · CPC title

• C08G2190/00

  Compositions for sealing or packing joints · CPC title

• C08G18/305

  creating amino end groups · CPC title