羊毛の防縮に関する研究

抄録

Investigations were made concerning the effects of various salt solutions on the quality of wool fibres in treating them with permanganate, and it was found that 2 mol solution of (NH₄)₂SO₄ was most effective among the solutions for the treatment of shrinkproofing without such adverse effects as yellowing and poor handling.
The cation of the salt solution did not show any special tendency to give a shrink-proof quality to the fibres, but its SO₄⁼ anion showed a tendency to improve the anti-felt treatment with permanganate.
With the increased concentration of the same salt solution, shrink-proof property of the treated yarn becomes better, its tensile strength larger, and its alkali solubility less. This may be attributable to the fact that the reaction occurres with the increased concentration, apt to be confined to the surface of the fibres mainly by their deswelling action and does not substantially hurt the fibres themselves.
Comparisons of physical properties between the wool fibres treated with KMnO₄/(NH₄)₂SO₄ solution and the ones treated with KMnO₄/H₂O solution revealed the following two facts. The static frictional coefficients between fibre-fibre as measured in their wet state by the Röder method showed an obvious difference from each other, at the same degree of concentration of KMnO₄ the former showed a smaller value of μ₂-μ₁ and a better shrink-proof effect than the latter.
Where the fibres were treated with KMnO₄/(NH₄)₂SO₄ solution, their values of both μ₁ and μ₂ became smaller up to 5% o. w. f. KMnO₄; but beyond that point those values tended to became larger.
This phenomenon could be seen from optical microscopic observations. The scale edges of the treated fibres tended to are collapse up to 5% o. w. f. KMnO₄; but beyond that point said edges are sunken, and only the central part of the scale remaines to be seen.
In the case of KMnO₄/H₂0 solution, however, such a concave structure is hardly noticeable even if 30% o. w. f. KMnO₄ solution was used.
It was found that there is a linear correlation between the values of μ₂-μ₁ of the shrink-proofed wool fibres and the rates of its felting shrinkage.
Half scales of wool fibres were first abrased by a glass edge along the fibre axis, and then the fibres were treated with KMnO₄ solution in the presence and absence of (NH₄)₂SO₄. In both cases, it was found that MnO₂ is deposited on the abrased side (cortex) but rarely, if any, on the other side (coticle) before reduction. This clearly indicates that the cortex is more reactive than the cuticle.