GB587153A - Solubilized cellulosic material and solutions thereof - Google Patents

Abstract

Solutions of cellulosic material are obtained by treating wood pulp, cotton linters or rayon in the form of powder, sheets or fibres, with an aqueous solution of sodium or potassium zincate of a concentration such that if established in a sodium zincate solution of the cellulose it would cause precipitation of the cellulose therefrom and diluting the mass of solubilized material by adding water, ice, dilute sodium hydroxide or dilute sodium zincate solution until the material dissolves. The solution may be used as a coating, an adhesive, or a spinning solution for the manufacture of threads and sheets. The cellulose used initially may be modified or degraded by heating the unmodified material to 50 DEG C. with a strong solution of sodium zincate. The zincate solution should contain an excess of alkali metal hydroxide and may be prepared by mixing zinc oxide, hydroxide, or a zinc salt with excess aqueous sodium hydroxide. The temperature of treatment may be as high as 50 DEG C. or as low as 5 DEG C., and when the solution temperature after dilution is below 15 DEG C., the solution is stabilized by warming promptly to 15 DEG C. or higher. The solution may be ripened before use. If desired, the concentrated zincate solution in the original treated mass may be pressed out and the treated cellulose stirred into a dilute solution of sodium zincate. Numerous examples are given, in one of which rayon staple fibre is stirred with a solution of sodium zincate at 50 DEG C. and the mass cooled to 25 DEG C. Ice is added gradually until the temperature falls to 3 DEG C. and until the cellulose is completely dispersed. The dispersion is then warmed promptly to 15 DEG C., and ripened for 24 hours at room temperature. Specification 573,767 is referred to.