| 摘要 |
Fibres are produced by introducing a fibre-forming material, pref. a liquid of viscosity 1-200 P, into an atomiser in a spray drying appts., the atomiser being adjusted so as to promote the formation of fibres rather than particles. The temp. in the drying chamber is held at a suitable level to dry the fibres which are then recovered under conditions under which they are intact. he fibre-forming material pref. comprises inorganic cpds. (pref. aq. solns.) which form oxides when heated or which form inorganic sols of high viscoelasticity. Pref. are denitrated zirconium nitrate or Al hydroxide-chloride. Alternatively other inorganic cpds. (e.g. basic acetates of Zr or Al) may be used which are fibre-forming in the presence of a spinning aid. The spinning aid is pref. a linear organic polymer, esp. polyoxyethylene, partially hydrolysed polyvinyl acetate or polyvinyl pyrrolidone. Used for prodn. of refractory fibres. The process gives polycrystalline fibres of dia. >1 mu and length >1 mm, which present no health hazards. |
