PROCESS FOR PRODUCING POWDER FROM NATURAL SILK Russian patent published in 1994 - IPC

FIELD: textile industry. SUBSTANCE: silk waste such as rags, strings, strips or cut shells of mulberry or oaken silkworm cocoons were treated in autoclave using 3 to 7 % by mass aqueous solution of oxalic acid at temperature of 105 to 120 C during 2 to 5 h. Solution drained, silk fibers were washed in water three times, kept in water at room temperature for 2 h and again washed in water three times after solution was neutralized by sodium hydroxide. Silk fibers were then centrifuged, dried at room temperature and comminuted in ball mill. About 10 g of mulberry silkworm waste yielded from 7.5 to 8.0 g white powder and 10 g of oaken silkworm yielded 9.5 g grey powder. Resultant powder was soft, had silky feel, produced characteristic "touch" crunch and was of homogeneous consistency. EFFECT: higher quality of end product.