Adhesives, Reaction Systems, and Processes for Production of Lignocellulosic Composites

Abstract

Adhesives, reaction systems, and processes for the production of lignocellulosic composites. The reaction system comprises a multi-component adhesive and a lignocellulosic substrate. The lignocelluosic substrate comprises a plurality of lignocellulosic adherends and is preferably a mass of wood particles. The multi-component adhesive comprises a multi-functional isocyanate, a hydrophilic polyahl, and an organotransition metal catalyst. The multi-component adhesive is characterized by being formulated into at least two mutually reactive chemical component streams. The process comprises the separate application of the mutually reactive chemical component streams of the multi-component adhesive to the lignocellulosic substrate, followed by forming and pressing the adhesive treated substrate under conditions appropriate for curing the adhesive and forming a lignocellulosic composite article. The adhesives, reaction systems, and processes are particularly well suited for the production of oriented strand board (OSB).

What is claimed: 
     
         1 . An adhesive treated lignocellulosic mixture comprising: a plurality of lignocellulosic substrates coated with an adhesive wherein the adhesive comprises: a polyfunctional isocyanate, a transition metal organometallic catalyst, a hydrophilic organic polyahl having oxyethylene segments that make up greater than 50% of the weight of the polyahl, and a non-isocyanate reactive additive. 
     
     
         2 . The adhesive treated lignocellulosic mixture of  claim 1  wherein the hydrophilic organic polyahl comprises a hydrophilic organic polyol and the transition metal organometallic catalyst comprises at least one metal selected from the group consisting of the metals of Groups IVB, VB, VIB, VIIB, and VIIIB of the Periodic Table of the Elements. 
     
     
         3 . The adhesive treated lignocellulosic mixture of  claim 2  wherein the hydrophilic organic polyol comprises a polyether polyol and the transition metal organometallic catalyst comprises at least one metal selected from the group consisting of the metals Group VIIIB of the Period Table of the Elements. 
     
     
         4 . The adhesive treated lignocellulosic mixture of  claim 3  wherein the transition metal organometallic catalyst comprises at least one organic compound of iron. 
     
     
         5 . The adhesive treated lignocellulosic mixture of  claim 4  wherein the organic compound of iron contains at least one chelating ligand. 
     
     
         6 . The adhesive treated lignocellulosic mixture of  claim 1  wherein the polyfunctional isocyanate comprises at least one isocyanate of the MDI series. 
     
     
         7 . The adhesive treated lignocellulosic mixture of  claim 3  wherein the polyether polyol has a number averaged molecular weight of between 300 and 10,000 and is prepared from an initiator having a number averaged functionality of from 2 to 10. 
     
     
         8 . The adhesive treated lignocellulosic mixture of  claim 7  wherein the polyether polyol has an oxyethylene content of at least 70% by weight, a number averaged molecular weight of between 700 and 2000, and is prepared from an initiator having a number averaged functionality of from greater than 2 to 4. 
     
     
         9 . The adhesive treated lignocellulosic mixture of  claim 1  wherein the non-isocyanate reactive additive is selected from the group consisting of fire retardants, pigments, dyes, antioxidants, light stabilizers, expanding agents, inorganic fillers, smoke suppressants, slack waxes, antistatic agents, internal mold release agents, inert liquid diluents, solvents, biocides, or combinations thereof. 
     
     
         10 . An adhesive treated lignocellulosic mixture comprising: a plurality of lignocellulosic substrates coated with an adhesive wherein the adhesive comprises: a polyfunctional isocyanate, a transition metal organometallic catalyst comprising at least one organic iron compound, a hydrophilic organic polyahl having oxyethylene segments that make up greater than 50% of the weight of the polyahl, and a non-isocyanate reactive additive. 
     
     
         11 . The adhesive treated lignocellulosic mixture of  claim 10  wherein the hydrophilic organic polyahl comprises a hydrophilic organic polyol and the transition metal organometallic catalyst comprises at least one metal selected from the group consisting of the metals of Groups IVB, VB, VIB, VIIB, and VIIIB of the Periodic Table of the Elements. 
     
     
         12 . The adhesive treated lignocellulosic mixture of  claim 11  wherein the hydrophilic organic polyol comprises a polyether polyol and the transition metal organometallic catalyst further comprises at least one metal selected from the group consisting of the metals Group VIIIB of the Period Table of the Elements. 
     
     
         13 . The adhesive treated lignocellulosic mixture of  claim 12  wherein the polyether polyol has a number averaged molecular weight of between 300 and 10,000 and is prepared from an initiator having a number averaged functionality of from 2 to 10. 
     
     
         14 . The adhesive treated lignocellulosic mixture of  claim 13  wherein the polyether polyol has an oxyethylene content of at least 70% by weight, a number averaged molecular weight of between 700 and 2000, and is prepared from an initiator having a number averaged functionality of from greater than 2 to 4. 
     
     
         15 . The adhesive treated lignocellulosic mixture of  claim 10  wherein the organic iron compound contains at least one chelating ligand. 
     
     
         16 . The adhesive treated lignocellulosic mixture of  claim 10  wherein the polyfunctional isocyanate comprises at least one isocyanate of the MDI series. 
     
     
         17 . The adhesive treated lignocellulosic mixture of  claim 10  wherein the non-isocyanate reactive additive is selected from the group consisting of fire retardants, pigments, dyes, antioxidants, light stabilizers, expanding agents, inorganic fillers, smoke suppressants, slack waxes, antistatic agents, internal mold release agents, inert liquid diluents, solvents, biocides, or combinations thereof.