Zein is dissolved in only sufficient alkali to form a stable, translucent solution of low viscosity which is stored, and further alkali thereafter added sufficient to form a bright, transparent solution. Aqueous alkali may be added in increments to avoid an excess, about 1-2 per cent of sodium hydroxide, based upon dry zein, being required. Usually the pH of the aqueous alkaline medium is not above 11.6. Solution and storage is usually effected at below 60 DEG C., preferably below 30 DEG C. Agents such as formaldehyde and butyl alcohol may be added to assist retention of low viscosity. The zein may be extracted from corn gluten with alcohols, e.g. 50-80 per cent, isopropyl alcohol at 40-70 DEG C., de-oiled with hydrocarbons, neutralized where alkali has been used, and precipitated in water. The solutions of low viscosity may be filtered and de-aerated, and can be stored for weeks at room temperature. When required for use for spinning, the additional alkali is added to increase the viscosity. In examples, solutions of zein containing 15-17 per cent by weight are made using percentages of sodium hydroxide between 1 and 2, the change of viscosity with time being indicated.
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