System for catalyzation of thermoset resin adhesives for wood composites using computerized in-line metering and mixing equipment

Abstract

The present invention provides a process and system for the manufacture of wood-based composites that implement feedback adjusted in-line addition of a curing accelerator/catalyst to a thermosetting resin adhesive based on at least one of: present moisture content of the wood substrate being bonded and the temperature of the wood substrate being bonded. The method includes: measuring the flow rate of a flowing stream of resin adhesive; measuring the flow rate of a flowing stream of accelerator/catalyst; mixing the flowing stream of accelerator/catalyst and the flowing stream of resin adhesive to form a mixed catalyzed resin adhesive in a proportion of resin adhesive and accelerator/catalyst determined by said flow rates; applying the mixed catalyzed resin adhesive to the wood substrate in an application area; measuring a present moisture content and a present temperature of the wood substrate prior to applying the mixed catalyzed resin adhesive thereto; varying on a continuous basis, the proportion of the accelerator/catalyst and resin adhesive in the mixed catalyzed resin adhesive in accordance with at least one of the present moisture content and the present temperature and bonding together said wood substrate to form said wood-based composite.

1 . A system for adding an accelerator/catalyst to a thermosetting resin adhesive during formation of a wood-based composite, comprising: 
 (a) a first flow meter positioned to measure a flow rate of a flowing stream of resin adhesive;    (b) a second flow meter positioned to measure a flow rate of a flowing stream of accelerator/catalyst being mixed with the resin adhesive;    (c) at least one of: 
 a pump positioned to pump the accelerator/catalyst for mixing with the resin adhesive, and  
 a valve positioned so as to control the amount of accelerator/catalyst mixed with the resin adhesive;  
   (d) at least one of: 
 a temperature sensor configured for determining a temperature of furnish material in a wood source supplying the furnish material for application with the mixed resin adhesive and accelerator/catalyst, and  
 a moisture sensor configured for determining a moisture of the furnish material in the wood source;  
   (e) a computer electrically coupled to the first and second flow meters, to the at least one of the pump and the valve, and to the at least one of the temperature and moisture sensors, wherein the computer is configured to: 
 receive the measured flow rates of the resin adhesive and accelerator/catalyst, receive at least one of the temperature and moisture of the furnish material, and  
 vary a proportion of the accelerator/catalyst being mixed with the resin adhesive in accordance with at least one of the moisture and temperature of the furnish material.  
   
     
     
         2 . The system of  claim 1 , wherein the computer is configured to vary a proportion of the accelerator/catalyst being mixed with the resin adhesive according to a predetermined temperature scheme for plywood under which, for phenolic resins and acetone formaldehyde accelerator/catalyst and a substrate temperature (T) range of 60-160° F., a percent accelerator/catalyst is determined using an equation substantially of a form:  
         percent accelerator/catalyst=8.17063−0.0115268× T− 0.000238928× T   2 ,  
       where T is the temperature of the plywood expressed in Fahrenheit degrees.  
     
     
         3 . The system of  claim 1  wherein the second computer is configured to vary a proportion of the accelerator/catalyst being mixed with the resin adhesive according to a predetermined temperature scheme for oriented strandboard furnish under which, for phenolic resins and resorcinol formaldehyde accelerator/catalyst and a temperature (T) range of 60-120° F., a percent accelerator/catalyst is determined using an equation substantially of a form:  
         percent accelerator/catalyst=16.0595−0.275× T+ 0.00119048× T   2 ,  
       where T is the temperature of the oriented strandboard furnish expressed in Fahrenheit degrees.  
     
     
         4 . The system of  claim 1  wherein the second computer is configured to vary a proportion of the accelerator/catalyst being mixed with the resin adhesive according to a predetermined temperature scheme for medium density fiberboard furnish under which, for urea formaldehyde resins and a thirty percent ammonium sulfate accelerator/catalyst and a substrate temperature (T) range of 55-115° F., a percent accelerator/catalyst is determined using an equation substantially of a form:  
         percent accelerator/catalyst=3.78022−0.0232967× T+   0.0×T   2 ,  
       where T is the temperature of the medium density fiberboard furnish expressed in Fahrenheit degrees.  
     
     
         5 . The system of  claim 1  wherein the second computer is configured to vary a proportion of the accelerator/catalyst being mixed with the resin adhesive according to a predetermined temperature scheme for particleboard furnish under which, for urea formaldehyde resins and a thirty percent ammonium sulfate accelerator/catalyst and a substrate temperature (T) range of 60-110° F., a percent accelerator/catalyst is determined using an equation substantially of a form:  
         percent accelerator/catalyst=4.33804−0.0319627× T+ 0.00002331× T   2 ,  
       where T is the temperature of the particleboard furnish expressed in Fahrenheit degrees.  
     
     
         6 . A system for adding an accelerator/catalyst to a thermosetting resin adhesive during formation of a wood-based composite, comprising: 
 (a) an in-line mixer receiving resin adhesive and accelerator/catalyst;    (b) a flow meter measuring a flow rate of the resin adhesive flowing to the in-line mixer;    (c) a computer receiving a signal from the flow meter, wherein the computer is configured to vary a proportion of the accelerator/catalyst being mixed with the resin adhesive according to at least one of the following predetermined temperature schemes: 
 (1) for forming plywood with phenolic resins and acetone formaldehyde accelerator/catalyst and a substrate temperature (T) range of 60-160° F., a percent accelerator/catalyst is determined using an equation substantially of a form:  
   percent accelerator/catalyst=8.17063−0.0115268× T− 0.000238928× T   2 ,  
 where T is the temperature of the plywood expressed in Fahrenheit degrees,  
 (2) for forming a composite using oriented strandboard furnish, phenolic resins and resorcinol formaldehyde accelerator/catalyst and a temperature (T) range of 60-120° F., a percent accelerator/catalyst is determined using an equation substantially of a form:  
   percent accelerator/catalyst=16.0595−0.275× T+ 0.00119048× T   2 ,  
 where T is the temperature of the oriented strandboard furnish expressed in Fahrenheit degrees,  
 (3) for forming a composite using medium density fiberboard furnish, urea formaldehyde resins and a thirty percent ammonium sulfate accelerator/catalyst and a substrate temperature (T) range of 55-115° F., a percent accelerator/catalyst is determined using an equation substantially of a form:  
   percent accelerator/catalyst=3.78022−0.0232967× T+   0.0×T   2 ,  
 where T is the temperature of the medium density fiberboard furnish expressed in Fahrenheit degrees, and  
 (4) for forming a composite using particleboard furnish, urea formaldehyde resins and a thirty percent ammonium sulfate accelerator/catalyst and a substrate temperature (T) range of 60-110° F., a percent accelerator/catalyst is determined using an equation substantially of a form:  
   percent accelerator/catalyst=4.33804−0.0319627× T+   0.00002331×T   2 ,  
 where T is the temperature of the particleboard furnish expressed in Fahrenheit degrees.