Abstract
The mulberry-cocoon-silk fibre consists of a filament of fibroin surrounded bysericin, that is also called silk-glu. This silk sericin is coagulated and fixed as it is, by coagulators such as Cr-salts formaldehyde or tannic acid. In the present paper the contraction of silk fibre or cocoon silk fibre which has been fixed with 20% formalin by means of acids or other swelling agents, is discussed chiefly concerning its tensile strength, elongation and crimp shrinkage. For the contraction of silk fibre HCl, H2SO4, Ca(SCN)2, and CaBr2 is used. The conclusion of this investigation is as follows;
(1) HCl is better than H2SO4, and a 28% solution is most suitable. As to the time of treating by HCl, 3 min. is inferrior to 1 min. for strength and elongation, but is better for crimp.
(2) when the durability of crimp elasticity is tested by weightening 750mg 5 hrs., yarn fixed with formalin is diminished by 10%, but yarn fixed with Cr-salts is diminished by 26%. The former then is better than the latter.
(3) CaBr2 is better than Ca(SCN)2, and a 20g/dl soiution is suitable. In the degree and number of crimp the former is better than the latter, but is inferrior in strength, elongation and crimp clasticity.
(4) In all phyisical properties fibre denatured with formalin is better than that denatured with Cr-salts except in the durability of crimp elasticity.
The above mentioned imitation wool fibre is better than modern staple fibres, bnt is far inferior to wool fibre.
