| 摘要 |
Regenerated cellulose products are treated successively with an aqueous solution of an alkali metal hydroxide and with acrylonitrile, the aqueous hydroxide having a normality of not greater than 0.7, and containing at least one alkali metal salt of sulphuric, nitric, hydrochloric, hydrobromic or hydrofluoric acid. "Regenerated cellulose products" include threads, staple fibres, films, tapes, woven and knitted fabrics consisting wholly or partly of regenerated cellulose. The products so treated show a decrease in the degree of swelling in water, and absorb less moisture from the atmosphere. In a preferred embodiment, the regenerated cellulose products are immersed in aqueous sodium hydroxide containing sodium sulphate or sodium chloride, and, if desired, a wetting agent at a temperature of e.g. 70-100 DEG C. The acrylonitrile for subsequent treatment may contain water or a diluent e.g. benzene, toluene, acetone or chloroform. Preferably the material is immersed in an azeotropic mixture of 88% acrylonitrile and 12% water at 70 DEG C. The reaction may also be carried out at higher temperatures under pressure. In an example, a film of regenerated cellulose is passed through an aqueous bath containing 1% of sodium hydroxide and 5% of sodium sulphate at 90 DEG C. for 1 minute. After removal of excess moisture by rollers, the film is passed for 1 1/2 minutes through a bath of 88% acrylonitrile and 12% water by weight at 70 DEG C. Removal of excess moisture is followed by washing with acetic acid, water and then drying.
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