US PATENT SUBCLASS 162 / 88
.~.~.~ Plural diverse stage treatments

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}
87  DF  .~.~ Chlorine containing {1}
88.~.~.~ Plural diverse stage treatments {1}
89  DF  .~.~.~.~> Alkali metal, ammoninum, alkaline earth metal or magnesium hydroxide or carbonate in at least one stage

DEFINITION

Classification: 162/88

(under subclass 87) Processes in which the fibrous material

is subjected to a plurality of separate, dissimilar chemical treatments, at least one of which involves treatment with a chlorine containing material.

(1) Note. The separate treatments may differ in composition or concentration of the treating medium, temperature or pressure, of the treatment, etc.