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US 4,163,840 AGranted
Process and apparatus for making alkali cellulose in sheet form
AssigneeFiber Associates, Inc.
InventorsCharles J. Geyer, Jr., Ben E. White
Life of this patent
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AssigneeFiber Associates, Inc.
InventorsCharles J. Geyer, Jr., Ben E. White
Estimating the term…
Improved process and apparatus for making alkali cellulose comprises continuously steeping indefinite length sheets of cellulose in an alkali hydroxide bath, generally 17-25% sodium hydroxide, and then passing the cellulose strip through a chamber where it is subjected to extremely rapid mercerizing conditions, including an RF energy field, to produce depolymerization thereof. Upon emergence from the steep bath, the cellulose passes to an excess solution removing means, such as one or a series of pairs of nip rolls where the excess solution is expressed from the cellulose and the amount of absorbed alkali is controlled. Preferably, the excess solution is recovered and returned to the steeping baths. A second, lower concentration, steep bath may follow the rapid mercerization step.
Process for continuously making alkali cellulose and depolymerizing it to a desired degree of polymerization comprising first contacting a cellulose sheet of indefinite length with 17-25% alkali hydroxide solution, removing said sheet from said solution and pressing out caustic soda solution followed by a rapid depolymerization process to bring about desired depolymerization of cellulose, said depolymerization process consisting of exposing said cellulose to RF energy for a period of time and at an energy input level sufficient to accomplish said depolymerization.
Dependencies are inferred from the claim text.