Process for producing regenerated cellulosic articles and for recovering the solvent chemicals

A process for producing regenerated cellulosic articles from cellulose which has been dissolved in a mixture of dimethyl sulfoxide (DMSO) and formaldehyde, and for recovering the solvent chemicals. The DMSO/formaldehyde solution of cellulose is brought into contact with an aqueous solution, the pH o...

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Hauptverfasser: ALKIO, MARTTI, AALTONEN, OLLI
Format: Patent
Sprache:eng
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Beschreibung
Zusammenfassung:A process for producing regenerated cellulosic articles from cellulose which has been dissolved in a mixture of dimethyl sulfoxide (DMSO) and formaldehyde, and for recovering the solvent chemicals. The DMSO/formaldehyde solution of cellulose is brought into contact with an aqueous solution, the pH of which is at least 9 and the adjustment of pH has been carried out by means of a base or an alkaline salt which does not react with formaldehyde and the content of which is at most 0.1% by weight, so that the product is coagulated and regenerated in the desired form, such as fibres, films or shaped articles. The coagulation solution is evaporated in one stage or plurality of stages so that the DMSO and formaldehyde of the cellulose solution remain in the evaporation residue. The evaporation residue is recycled for the production of cellulose solution, purified, if so required.