Process of forming an expanded lightweight foamed product from rice hulls
AssigneeBiofoam Industries, Inc.
InventorCharles L. Capps
Life of this patent
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Abstract
Plant waste products high in cellulose and silica, i.e. rice hulls, are converted into a slurry of water and a silicate cross-linked cellulose polymer by digestion under heat and pressure in the presence of sodium ions and a sulfite. The slurry is treated with conventional foaming agents to form a formed product expanded in volume. The foamed product may be formed into any desired shape or size by extrusion, molding or casting.
Claims12
The process of forming an expanded lightweight cellular body comprising the steps of:
- (a) digesting rice hulls to form a slurry by:
- (i) heating said rice hulls under pressure in the presence of sodium sulfite, thereby causing the rice hull material to be broken into its basic cellular components and produce a first stage slurry;
- and
- (ii) heating said first stage slurry under pressure in the presence of sodium bisulfite and sulfuric acid, thereby causing hydrolysis to occur and produce thermochemically altered cellulose which forms a silicate cross-linked cellulose polymer;
- (b) foaming the slurry by injection of gas thereto;
- and
- (c) drying the foamed product to form a rigid self-supporting body.
The process of forming an expanded lightweight cellular body comprising the steps of:
- (a) forming a slurry by digesting rice hulls in a first digesting stage wherein the rice hull material is broken into its basic cellular components and a second digesting stage wherein hydrolysis occurs to produce thermochemically altered cellulose which forms a silicate cross-linked cellulose polymer;
- (b) foaming the slurry by injection of gas thereto;
- and
- (c) drying the foamed product to form a rigid self-supporting body.
The process of forming an expanded lightweight cellular body comprising the steps of:
- (a) digesting rice hulls to form a slurry containing a silicate cross-linked cellulose polymer by:
- (i) heating said rice hulls under pressure in the presence of sodium sulfite to produce a first stage slurry;
- and
- (ii) heating said first stage slurry under pressure in the presence of sodium bisulfite and sulfuric acid;
- (b) foaming the slurry by injection of gas thereto;
- and
- (c) drying the foamed product to form a rigid self-supporting body.
Dependencies are inferred from the claim text.