Process and apparatus for making alkali cellulose in sheet form

Abstract

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.

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