Method for Treating Lignocellulosic Parts

Abstract

A method for treating lignocellulosic parts for producing foamed or foam-like parts, including: drying the lignocellulosic parts, the drying involving removing water, wherein the drying is achieved by applying at least one liquid drying agent that dissolves and/or at least partly replaces the water, wherein preferably the drying agent is a swelling agent for lignocellulose; and chemical modification, by etherification of the dried lignocellulosic parts; wherein the chemical modification is such that a volume of the lignocellulosic parts is increased by at least 25% with respect to an initial volume of the parts.

1 . A method for treating lignocellulosic parts for producing foamed or foam-like parts, including:
 drying the lignocellulosic parts, the drying involving removing water, wherein the drying is achieved by applying at least one liquid drying agent that dissolves and/or at least partly replaces the water, wherein preferably the drying agent is a swelling agent for lignocellulose; and   chemical modification by etherification, of the dried lignocellulosic parts;   wherein the modification involves subjecting the lignocellulosic parts to a reactant and a catalyst, the reactant and catalyst being supplied in an amount to expand the lignocellulosic parts, wherein the chemical modification is such that a volume of the lignocellulosic parts is increased by at least 25% with respect to an initial volume of the parts.   
     
     
         2 . The method according to  claim 1 , wherein a water content of the lignocellulosic parts is lower than 5 w %, preferably lower than 3 w %, after the drying and before the modification is started. 
     
     
         3 . The method according to  claim 1 , wherein the modification is an epoxide based etherification. 
     
     
         4 . The method according to  claim 3 , wherein the catalyst is a tertiary amine, for example di-methyl-ethyl-amine (DMEA). 
     
     
         5 . The method according to  claim 4  wherein the catalyst is tri methyl amine (TMA) 
     
     
         6 . The method according to  claim 1 , wherein the modification involves subjecting the lignocellulosic parts to an epoxide, such as an alkylene oxide, for example propylene oxide. 
     
     
         7 . The method according to  claim 1 , wherein a volume of the lignocellulosic parts is increased by 100% or more, 
     
     
         8 . The method according to  claim 1 , wherein a volume of the lignocellulosic parts is increased by 400% or more. 
     
     
         9 . The method according to  claim 1 , wherein the lignocellulosic parts to be treated have an initial density (kg/m 3 ), wherein the modification is such that the density of the lignocellulosic parts is lowered with respect to the initial density, for example by a factor of at least 50%. 
     
     
         10 . The method according to  claim 1 , wherein the drying includes:
 a) subjecting the lignocellulosic parts to the drying agent, particularly to impregnate the lignocellulosic parts with that drying agent to dissolve and replace water;   b) removing at least part of the drying agent from the lignocellulosic parts, for example such that a remaining amount of drying agent provides swelling of the lignocellulosic parts;   c) optionally repeating steps a) and b).   
     
     
         11 . The method according to  claim 1 , wherein the drying involves saturating the lignocellulosic parts with the drying agent. 
     
     
         12 . The method according to  claim 1 , wherein the drying agent is selected from the group consisting of an organic solvent, propylene oxide, butylene oxide, lower ethers, ethylene glycol dimethylether (EGDME), tetrahydrofuran (THF), small ketones, acetone, MEK (methylethyl ketone), lower esters, methyl-, ethyl-, propyl- and isopropylacetate. 
     
     
         13 . The method according to  claim 1 , wherein at least part of the drying is carried out under subatmospheric pressure, for example a pressure lower than 0.5 bar, for example about 0.1 bar. 
     
     
         14 . The method according to  claim 1 , wherein a water content of the lignocellulosic parts is lower than 1 w %. 
     
     
         15 . An insulating element, comprising one or more foamed or foam-like parts produced by the method of  claim 1 . 
     
     
         16 . The insulating element of  claim 15 , wherein a water content of the lignocellulosic parts is lower than 5 w %, preferably lower than 3 w %, after the drying and before the modification is started. 
     
     
         17 . The insulating element of  claim 15 , wherein the modification is an epoxide based etherification. 
     
     
         18 . The insulating element of  claim 17 , wherein the catalyst is a tertiary amine, for example di-methyl-ethyl-amine (DMEA). 
     
     
         19 . The insulating element of  claim 18 , wherein the catalyst is trimethyl amine (TMA) 
     
     
         20 . The insulating element of  claim 15 , wherein the modification involves subjecting the lignocellulosic parts to an epoxide, such as an alkylene oxide, for example propylene oxide.