Method for the production of high density fiberboard
AssigneeUnited States Gypsum Company
InventorsDennis L. Hardesty, Timothy D. Hanna, Frank J. Wendt, Kendall D. White, Jr.
Life of this patent
Estimating the term…
Abstract
High strength and high density wood fiberboard is formed by treating the wood fiber source material with a highly alkaline solution, such as sodium hydroxide solution, before interfelting the fibers into a loose mat. The wood source material may be treated after refining the material into fibers, but preferably, the wood source material is treated before fibrillation. Further, wood fiber source material may be partially neutralized before felting without substantial change in the resulting densities and strengths.
Claims8
A process for making wood fiberboard of the type in which:
- (1) a wood fiber source material is fibrillated into fibers,
- (2) the fibers are interfelted into a loose mat,
- (3) the mat is lightly roll compressed,
- (4) and the mat is dried and finished to form a fiberboard product of at least about 1/8th inch thickness, characterized by the improvement of the steps:
- consisting essentially of:
- mechanically fibrillating raw wood chips with essentially simultaneous addition of a highly alkaline aqueous solution sufficient to form an aqueous slurry having a pH of at least about pH 12, fibrillating said wood chips at a temperature below the boiling point of said aqueous slurry and imparting an about at least three-fold increase in the zeta potential of fibers from the fiber source material, whereby densities greater than about 20 pounds per cubic foot and strengths greater than 500 psi modulus of rupture are obtained.
A process for making a high density, high strength wood fiberboard, having a density greater than about 24 pounds per cubic foot and a modulus of rupture greater than about 800 psi comprising the steps of:
- (a) forming an aqueous slurry of wood chips and water and feeding the slurry to a mechanical refiner;
- (b) feeding a highly alkaline aqueous solution to the refiner and refining the solution and wood chips slurry at a temperature below the boiling point of said aqueous slurry containing said alkaline solution to refine the chips into a fiber slurry haviing a pH of about 13-14;
- (c) neutralizing the fiber slurry to a pH of about 9-11;
- (d) interfelting the fiber slurry into a loose fiber mat;
- and
- (e) expressing water from the mat and drying the mat to form a finished fiberboard.
Dependencies are inferred from the claim text.