| 摘要 |
A composition is prepared by mixing a finely ground water-soluble alginate, preferably ammonium alginate or an alkali metal alginate such as sodium alginate, and a finely-ground substantially water-insoluble alginate, preferably an alkaline earth metal alginate such as calcium alginate, in such proportions that the resulting composition will interact with water to form a gel. Preferably 25 to 35 per cent of the total weight of alginate is calcium alginate and 75 to 65 per cent is soluble alginate. A small amount of finely-ground alginic acid may be mixed with the composition to control pH, preferably to between 6.8 and 7.8. In preparing an alginate water gel the alginates may be mixed as powders before being dispersed in the water, the insoluble alginate may be added to an aqueous solution of the soluble alginate, preferably either by sifting the insoluble alginate into the solution as a dry powder or by adding the insoluble alginate in the form of a water slurry, or the alginates may be added to the water simultaneously but separately. The insoluble alginate may contain occluded in it a quantity of a soluble metallic salt used in its preparation, such as calcium chloride, and the soluble alginate may be a phospho-alginate or other alginate of the type described in Specification 502,609. Reference has been directed by the Comptroller to Specification 555,940. |
