Patent ID: 7183339

Claim:
A method of making a dimensionally stable composite product from lignocellulosic material, comprising: a) bringing the lignocellulosic material in divided form into contact with high pressure steam at a temperature high enough to decompose and hydrolyze hemicellulose and lignin contained in said lignocellulosic material without carbonization thereof; b) maintaining the lignocellulosic material in contact with high pressure steam for a time sufficient only for the decomposition and hydrolysis of hemicellulose and lignin into low molecular weight, water-soluble resin material including pentose and hexose sugars, sugar polymers, furfural products, dehydrated carbohydrate and organic acids and low molecular weight lignins and other lignin decomposition products, with negligible degradation of cellulose; c) drying the hydrolyzed lignocellulosic material; d) forming the residue of the lignocellulosic material, in comminuted form, and including low molecular weight lignins and other lignin decomposition products formed in step b), together with low molecular weight, water-soluble resin material including pentose and hexose sugars, sugar polymers, furfural products, dehydrated carbohydrate and organic acids derived from decomposition and hydrolysis of one or more of hemicellulose and cellulose, into a mat or web; and e) compressing the said mat or web at a temperature and a pressure for a sufficient time to polymerise, cross-link, and thermoset the water-soluble resin material and lignin decomposition products into an adhesive which forms a bond “in situ” yielding a reconstituted composite product.