Method for production of lignocellulosic composite materials

Abstract

Fibers of annual plants e.g. straw for use in forming composite products are improved by hydrothermal treatment at 40° to 120 ° C. with or followed by high shear treatment. The process enables the use of annual plant fibrous materials not hitherto usable successfully.

1 . A method for producing composite materials comprising the steps of: 
 a) providing a fibrous lignocellulosic material which is an annual plant residue,    b) subjecting the annual plant residue to treatment with water or steam at 40° C. to 120° C.,    c) simultaneously or subsequently subjecting the annual plant residue to a high shear treatment,    d) subjecting the treated annual plan residue to heat and pressure in the presence of a resin bonding agent.    
     
     
         2 . A process according to  claim 1 , wherein the annual plant fibre residue is a straw.  
     
     
         3 . A process according to any preceding claim, wherein the annual plant residue is treated with a lignocellulose modification agent, for example a metal hydroxide, organic or inorganic acid, a salt, and oxide, an amine or urea.  
     
     
         4 . A process according to  claim 3 , wherein the lignocellulose modification agent is added to the hydrothermal treatment during the high shear treatment stage.  
     
     
         5 . A process according to any preceding claim, wherein at least part of the resin bonding agent is added to the high shear treatment stage.  
     
     
         6 . A process according to any preceding claim in which a sizing agent is added to the fibrous material or in the resin addition.  
     
     
         7 . A process according to any preceding claim in which the fibrous material is combined with wood particles.