FIBERBOARDS, USES AND METHODS OF PREPARATION THEREOF
There is provided a fiberboard, such as a MDF fiberboard or a HDF fiberboard, comprising wood fibers, a binder, and a sludge such as a pulp and a paper sludge. The sludge can be, for example, chosen from a primary pulp and paper sludge, a secondary pulp and paper sludge, a de-inking sludge, and mixtures thereof.
1 . A fiberboard comprising:
wood fibers;
a binder; and
a pulp and paper sludge,
wherein said fiberboard is a medium density fiberboard or a high density fiberboard.
2 . The fiberboard of claim 1 , wherein said wood fibers are virgin wood fibers, post-consumption wood fibers, or a mixture thereof.
3 . The fiberboard of claim 1 , wherein said sludge is present in said fiberboard in an amount of at least 1% by weight, based on the total dry weight of the fiberboard.
4 . The fiberboard of claim 1 , wherein said sludge is present in said fiberboard in an amount of at least 5% by weight, based on the total dry weight of the fiberboard.
5 . The fiberboard of claim 1 , wherein said sludge is present in said fiberboard in an amount of at least 10% by weight, based on the total dry weight of the fiberboard.
6 . The fiberboard of claim 1 , wherein said sludge is present in said fiberboard in an amount of about 1% to about 40%, based on the total dry weight of the fiberboard.
7 . The fiberboard of claim 1 , wherein said sludge is present in said fiberboard in an amount of about 4% to about 15%, based on the total dry weight of the fiberboard.
8 . The fiberboard of claim 1 , wherein said fiberboard has substantially the same properties than a conventional fiberboard.
9 . The fiberboard of claim 1 , wherein said sludge is chosen from a primary pulp and paper sludge, a secondary pulp and paper sludge, a de-inking sludge, and mixtures thereof,
10 . The fiberboard of claim 3 , wherein said sludge is a primary pulp and paper sludge.
11 . The fiberboard of claim 3 , wherein said sludge is a mixture of primary pulp and paper sludge and a secondary pulp and paper sludge.
12 . The fiberboard of claim 1 , wherein said sludge is a substantially untreated primary sludge taken from a paper mill.
13 . The fiberboard of claim 1 , wherein said fiberboard has an internal bond strength of at least 1.30 kN/mm 2 .
14 . The fiberboard of claim 9 , wherein said fiberboard has an internal bond strength of at least 1.40 kN/mm 2 .
15 . The fiberboard of claim 1 , wherein said fiberboard has an internal bond strength of at least 1.70 kN/mm 2 .
16 . The fiberboard of claim 1 , wherein said fiberboard has an internal bond strength of at least 1.90 kN/mm 2 .
17 . The fiberboard of claim 7 , wherein said fiberboard has an internal bond strength of about 1.3 kN/mm 2 to about 1.98 kN/mm 2 .
18 . (canceled)
19 . The fiberboard of claim 17 , wherein said fiberboard is a high density fiberboard having a density of at least 800 kg/m 3 .
20 . The fiberboard of claim 1 , wherein said fiberboard is a high density fiberboard having a density of at least 900 kg/m 3 .
21 . The fiberboard of claim 3 , wherein said fiberboard is a high density fiberboard having a density of about 800 kg/m 3 to about 950 kg/m 3 .
22 . The fiberboard of claim 1 , wherein said binder is chosen from formaldehyde-based resins, isocyanate-based resins, and mixtures thereof.
23 . In a medium density fiberboard or a high density fiberboard comprising wood fibers and a resin, the improvement wherein at least a portion of the wood fibers are replaced with recycled fibers obtained from a sludge chosen from a primary pulp and paper sludge, a secondary pulp and paper sludge, a de-inking sludge, and mixtures thereof.
24 . A fiberboard obtained by pressing a mixture comprising
wood fibers;
a binder; and
as a pulp and paper sludge.
25 . A process for treating sludge, said process comprising screening a pulp and paper sludge having a dryness of about 0.5% to about 10%, through a screen of 160 μm or coarser, in order to at least partially reduce the amount of ashes contained in said sludge.
26 . The process of claim 25 , further comprising mixing the treated sludge with wood fibers and a binder so as to obtain a composition, drying said composition, and pressing said dried composition so as to obtain a medium density fiber board or a high density fiberboard.