Method of molding using dissociated lignocellulosic material and the product so produced
OwnerEdward A. DeLong, Edward P. DeLong +1inventors
InventorsEdward A. DeLong, Edward P. DeLong, George S. Ritchie
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Abstract
Dissociated lignocellulosic material produced by a process of explosive depressurization is molded into products of widely varying densities. Various fibrous and woody materials can be incorporated into the molded product to give a wide range of nailing and strength characteristics. Color, water repellent, preservative and fire retardant materials can be mixed with the material before molding. Other aggregates can be bound into the molded product which can contain fire enhancement materials for fuel.
Claims25
A method of molding dissociated lignocellulosic material comprising the steps of:
- (A) preparing the dissociated lignocellulosic material by;
- (1) packing lignocellulosic material in a divided, moist form in a pressure vessel having a valved outlet,
- (2) with the valve closed, rapidly filling the pressure vessel with steam at a pressure of at least 400 psi to bring substantially all of the lignocellulosic material to a temperature in the range of 185.degree. C. to 240.degree. C. in less than 60 seconds to thermally soften the lignocellulosic material into a plastic condition,
- (3) as soon as the plastic condition has been attained, opening the valved outlet and instantly and explosively expelling the lignocellulosic material from the pressure vessel to atmosphere,
- and wherein the explosive expulsion breaks the chemical cross-link between the lignin and hemicellulose of the lignocellulosic material and produces a mixture of water-soluble chemical substances, whereby dissociated lignocellulosic material is produced;
- (B) washing the said dissociated lignocellulosic material with water to substantially remove the said water-soluble chemical substances;
- (C) adding a cross-linking agent and catalyst therefor to the washed dissociated lignocellulosic material to provide a moldable dissociated lignocellulosic material, said cross-linking agent being selected from the group consisting of a five carbon sugar, a six carbon sugar, their glycosides and conjugates, furfural, and hydroxymethylfurfural, and mixtures thereof, and said catalyst being an acidic catalyst;
- (D) drying the moldable dissociated lignocellulosic material to a water content of about 5% or less;
- (E) packing the moldable material into a heated, vented mold;
- (F) applying sufficient pressure in the range of 20-700 psi for a sufficient time in the range of 5 seconds to 30 minutes and at a sufficient temperature in the range of 70.degree. C. to 260.degree. C. to the moldable material in the mold to cause it to form a rigid product;
- and
- (G) discharging the molded product from the mold.
Dependencies are inferred from the claim text.