The present inventors have discovered that the solution rheology of cellulose
ethers prepared from cellulose pulp is altered by mercerizing and recovering cellulose
pulp before preparing the cellulose ethers. For example, the solution viscosity
of carboxymethyl cellulose (CMC) produced from mercerized and recovered cellulose
pulp is significantly greater than that produced from non-mercerized cellulose
pulp. The present invention provides a method of preparing cellulose ethers comprising
the steps of (a) obtaining mercerized and recovered cellulose pulp, and (b) converting
the mercerized and recovered cellulose pulp into the cellulose ethers. According
to one embodiment, the cellulose pulp is southern softwood kraft and the mercerized
cellulose pulp has a TAPPI 230 om-89 viscosity of at most 12 cP. This method, however,
may be applied to all cellulose pulps, regardless of their viscosities, including
those which, when mercerized, have a viscosity greater than 12 cP. The mercerized
cellulose pulp is typically substantially free of cellulose III. Mercerized cellulose
pulp prepared by this method has a greater percentage of crystalline cellulose
II and a smaller crystalline area than that of non-mercerized cellulose pulp. The
present invention also provides a method of preparing a cellulose floc comprising
the steps of (a) obtaining mercerized and recovered cellulose pulp, and (b) treating
the mercerized pulp to form the cellulose floc. Alternatively, the method comprises
mercerizing and recovering a cellulose floc. Cellulose floc prepared by this method
have a greater bulk density than cellulose floc prepared from similar non-mercerized
cellulose pulp. Furthermore, the bulk density gain is greater than that expected
from the coarseness (weight per unit of fiber length) gain from preparing a cellulose floc.