| 摘要 |
309,147. I. G. Farbenindustrie Akt.- Gas. April 5, 1928, [Convention date]. Addition to 306,971. Cellulose xanthates. - The process of the parent Specification is modified in that organic oxy-acids, such as tartaric, citric, or lactic acids, or alkali salts of such acids, are added to viscose or one or more of the materials used in making the viscose instead of oxalic acid or its alkali salts and the viscose is precipitated in a bath consisting of a solution of sulphuric acid and sodium sulphate. The amount of the organic oxy-acid or its salt added may vary with the technical requirements but from 0.1-1 per cent is usual. In an example, 5 grams of potassium bitartrate are dissolved while stirring in 1 litre of viscose, which is then worked up by coagulation in a bath consisting of a solution of sodium sulphate and sulphuric acid. Specification 2992/13 is referred to.
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