US PATENT SUBCLASS 162 / 82
.~.~ Sulfur containing


Current as of: June, 1999
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162 /   HD   PAPER MAKING AND FIBER LIBERATION

1  DF  PROCESSES OF CHEMICAL LIBERATION, RECOVERY OR PURIFICATION OF NATURAL CELLULOSE OR FIBROUS MATERIAL {33}
70  DF  .~ Treatment with particular chemical {9}
82.~.~ Sulfur containing {1}
83  DF  .~.~.~> Sulfur dioxide or sulfite {1}


DEFINITION

Classification: 162/82

(under subclass 70) Processes in which a chemical containing sulfur is employed.

(1) Note. This subclass includes, for example, processes of parchmentizing with sulfuric acid.