| 摘要 |
1,121,074. Producing viscose rayon staple fibres. GLANZSTOFF A.G. 30 July, 1965 [31 July, 1964], No. 32738/65. Heading B5B. Viscose rayon staple fibres are produced by spinning viscose having a gamma number of 80 into a first stage aqueous coagulating bath maintained at 31‹ C., containing 8 to 10.8% by weight of sodium sulphate, 6À5 to 7% by weight of sulphuric acid and 0À78 to 0À83% by weight of formaldehyde, but no zinc salt, withdrawing the filaments thereby formed from the bath, stretching them in air to an elongation of 70%, passing them through a second stage aqueous bath containing 2% by weight of sulphuric acid and 1 to 10% by weight of sodium sulphate, the bath being maintained at 78 to 85‹ C. and the filaments being further stretched in this bath to such en extent that the overall increase in length of the filaments is 280 to 300%, thereafter cutting the filaments to staple fibre length to produce staple fibres having a gamma number between 35 and 47 (preferably between 40 and 47) and immersing the staple fibres for one minute in a third stage aqueous bath containing 0.1 to 6.0% of sulphuric acid and 1 to 10% sodium sulphate, the bath being maintained at a temperature from 90‹ C. up to its boiling point. The fibres are thereby completely regenerated. The staple fibres may be formed into a fleece and the fleece washed and treated with dilute sodium hydroxide solution.
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