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Mechanism of color development of the mud-mordanting dyed Oshima Tsumugi was studied by color measuring of dyed fabrics by defferent process ("Sharinbai" dyeing, Ca mordanting, Fe mordanting, mud-mordanting, separately). The result was as follows : [table

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Mechanism of flame retardation of the mud-mordanting dyed Oshima Tsumugi has been studied by several flammability tests (FF3-71,JIS L 1091 A-4,MAFT, Oxygen index) and SEM observation. The results were as follows : (1) Silk protein : High nitrogen content and low heat of combustion (2) Tannin : Char forming characteristics→suppress flaming combustion (3) Fe, (Ca) : Promoting the carbornization→increase in the char (4) Tannin-Ca-Fe complex : Covering the fiber→form an insulating char on the surface of the fiber→thermal barrier (1)+(2)+(3)+(4)→High flame retardanc