Method of preparing lignocellulose hardboard

Claim 1

A METHOD OF PREPARING IMPROVED LIGNOCELLULOSE HARDBOARD WHICH COMPRISES ARRANGING IN SURFACE TO SURFACE RELATIONSHIP TWO RELATIVELY LIGHT AND POROUS SHEETS OF FELTED LIGNOCELLULOSE FIBERS, SAID SHEETS BEING SEPARATED FROM EACH OTHER BY A RELATIVELY THIN LAYER OF SEPARATING MATERIAL, CONSOLIDATING AND DENSIFYING SAID SHEETS TO AN APPARENT DENSITY OF ABOUT 1.0-1.3 UNDER HEAT AND PRESSURE BETWEEN SMOOTH PRESSING PLATES, SAID CONSOLIDATION STEP BEING CARRIED OUT AT A PRESSURE WITHIN THE RANGE OF FROM ABOUT 500 P. S. I. TO ABOUT 2,000 P. S. I. AND AT A TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 450* F. TO ABOUT 350* F., RELEASING THE PRESSURE AND SEPARATING THE DENSIFIED SHEETS WHICH ARE CHARACTERIZED BY SMOOTH FRONT SURFACES AND BY BACK SURFACES CONTAINING APPRECIABLE IRREGULARITIES, ABRADING THE BACK SURFACES OF THE DENSIFIED SHEETS TO REMOVE THE IRREGULARITIES THEREFROM, AND THEN REPRESSING SAID SHEETS BETWEEN SMOOTH PRESSING PLATES UNDER HEAT AND PRESSURE SUFFICIENT TO FURTHER DENSIFY THE SHEETS TO A SPECIFIC GRAVITY OF ABOUT 1.3-1.4 WHEREBY THERE IS PRODUCED LIGNOCELLULOSE HARDBOARD CHARACTERIZED BY SUBSTANTIALLY UNIFORM DENSITY THROUGHOUT ITS ENTIRE AREA.

Claim 2

A METHOD OF PREPARING IMPROVED LIGNOCELLULOSE HARDBOARD WHICH COMPRISES ARRANGING IN SURFACE TO SURFACE RELATIONSHIP TWO RELATIVELY LIGHT AND POROUS SHEETS OF FELTED LIGNOCELLULOSE FIBERS, SAID SHEETS BEING SEPARATED FROM EACH OTHER BY A RELATIVELY THIN LAYER OF SEPARATING MATERIAL, CONSOLIDATING AND DENSIFYING SAID SHEETS TO AN APPARENT DENSITY OF ABOUT 1.0-1.3 UNDER HEAT AND PRESSURE BETWEEN SMOOTH PRESSING PLATES, SAID CONSOLIDATION STEP BEING CARRIED OUT AT A PRESSURE WITHIN THE RANGE OF FROM ABOUT 500 P. S. I. TO ABOUT 2,000 P. S. I. AND AT A TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 450* F. TO ABOUT 350* F., RELEASING THE PRESSURE AND SEPARATING THE DENSIFIED SHEETS WHICH ARE CHARACTERIZED BY SMOOTH FRONT SURFACES AND BY BACK SURFACES CONTAINING APPRECIABLE IRREGULARITIES, ABRADING THE BACK SURFACES OF THE DENSIFIED SHEETS TO REMOVE THE IRREGULARITIES THEREFROM, AND THEN REPRESSING SAID SHEETS BETWEEN SMOOTH PRESSING PLATES UNDER HEAT AND PRESSURE SUFFICIENT TO FURTHER DENSIFY THE SHEETS TO A SPECIFIC GRAVITY OF ABOUT 1.3-1.4 WHEREBY THERE IS PRODUCED LIGNOCELLULOSE HARDBOARD CHARACTERIZED BY SUBSTANTIALLY UNIFORM DENSITY THROUGHOUT ITS ENTIRE AREA.