Process for the preparation of semi-cellulose

Claim 1

PROCESS FOR THE PREPARATION OF SEMI-CHEMICAL CELLULOSE WHICH COMPRISES TREATING CELLULOSE-CONTAINING RAW MATERIALS OBTAINED FROM FOLIACEOUS TREES, CONIFEORUS TREE AND ANNUAL PLANTS WITH BUFFERED BISULFITE COOKING SOLUTIONS CONSISTING OF AQUEOUS SULFUR DIOXIDE CONTAINING ABOUT 1.4-3% SULFUR DIOXIDE AND A BASE SELECTED FROM THE GROUP CONSISTING OF THE HYDROXIES OF CALCIUM, MAGNESIUM, SODIUM, AND AMMONIUM,IN AN AMOUNT, DEPENDING UPON THE BASE AND CELLULOSE RAW MATERIAL EMPLOYED, TO PROVIDE AN INITIAL PH VALUE OF 3.5-6, COOKING WITH SAID SOLUTION IN THE PRESENCE OF A BUFFER SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL HAXAMETAPHOSPHATES, TRIPOLYPHOSPHATES, POLYPHOSPHATES AND PYROPHOSPHATES AT A REACTION TEMPERATURE OF 115-140*C., TO REPRESS THE EXCESSIVE HYDROLYTIC DECOMPOSITION OF THE CELLULOSE AND TO REMOVE A SUBSTANTIAL AMOUNT OF THE LIGNIN BINDING THE CELLULOSE FIBERS IN THE MIDDLE LAMALLAE, AND THEREAFTER MECHANICALLY SUBDIVIDING THE PRODUCT INTO INDIVIDUAL FIBERS.