| 摘要 |
<p>Artificial fibres, filaments, threads, fabrics, films, ribbons and the like of alginic acid, or of a water-insoluble alginate/alginic acid mixture, are exposed to the action of gaseous ammonia, or a gaseous alkyl amine such as mono-, di- or tri-methylamine. The treatment may be controlled so as to produce materials of desired degrees of water-solubility. The treated materials may be used as water-soluble wrapping materials or used in surgery. Water-insoluble alginate filaments may be treated with an acid such as hydrochloric acid to convert the whole or part of the alginate to alginic acid. Alginic acid filaments so obtained may be treated with a solution of a salt of a metal which forms a water-insoluble alginate so as to obtain filaments of a water-insoluble alginate/alginic acid mixture. In an example, calcium alginate fabric is treated successively with a 3 per cent, a 2 per cent and a 1 per cent solution of hydrochloric acid. The alginic acid fabric is washed, and dried on a stenter. It is then suspended in a chamber on the floor of which is placed a vessel containing 0.88 ammonia solution, and is exposed to the gaseous ammonia for 60 hours. The fabric so treated is soluble in water. In another example calcium alginate fibres are treated with hydrochloric acid solution to convert the alginate into alginic acid. Samples of the alginic acid fibres are placed in three sacks and exposed for 24 hours to the vapours of mono-, di- and tri-methylamine respectively. Specification 653,341 is referred to.</p> |
