| 摘要 |
306,971. I. G. Farbenindustrie Akt.- Ges. Feb. 28, 1928, [Convention date]. Cellulose xanthates.-Oxalic acid or its alkali salts are added to viscose at any stage of its manufacture. Thus for example, an alkali oxalate may be introduced into the solvent used in making the viscose solution from the cellulose xanthate or into the water used in making this solvent or it may be added to the finished viscose. The oxalic acid or oxalate, is preferably employed to the amount of 1 to 10 grams. per litre of viscose but larger or smaller quantities may be used. The products prepared from such viscose have a clear bright tint and uniform appearance and the spottiness or coloured streaks resulting from the presence of heavy metal compounds are either entirely avoided or diminished.
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