| 摘要 |
<p>In the manufacture of artificial materials from viscose, the viscose is shaped and its decomposition effected in the presence of an ortho-phosphoric acid ester of the formula <FORM:0907608/IV(a)/1> where the R groups may be the same or different and each is a -C2H4- or -C3H6- residue and the sum of the values (x+y+z) is 18 to 60. Suitable esters include polyethylene glycol esters, polypropylene glycol esters and polyethylene-polypropylene glycol esters. The ester may be added to the viscose solution, suitably in an amount of 0,05-0,4% by weight of the viscose. Preferably the addition amounts to 1,6-2,4% of the weight of cellulose present in the viscose. The ester may also be added to the decomposition bath, suitably in an amount of 0,005-0,04% by weight of the bath, which may contain sulphuric acid and zinc sulphate, and, if desired, iron, manganese, or nickel sulphates, which may partly replace the zinc sulphate. Such a bath may contain 10-25%, preferably 15-22%, anhydrous sodium sulphate, 3-15%, preferably 4-12%, anhydrous zinc sulphate and 6-10% by weight sulphuric acid. Bath temperatures of 25 DEG -80 DEG C., especially 45 DEG -70 DEG C., are preferred, 55 DEG -65 DEG C. being used when making type cord. The viscose may be extruded to form filaments, ribbons or films which may be stretched continuously with their production, e.g. in the decomposition bath or in a second, dilute acid, bath. Filaments so spun have a high tenacity and a high skin/core ratio, and may consist entirely of skin. Ribbons and films so spun exhibit smooth surfaces and enhanced transparency.</p> |
