Page 152 - Handbook of Properties of Textile and Technical Fibres

130 Handbook of Properties of Textile and Technical Fibres

uptake of nonionic textile finishing agents, e.g., moth-proofing agents (Zahn, 1980)
has been found in the medulla of coarse keratin fibers.
In dyeing, kemp fibers are the source of more visible problems than medullated fi-
bers. Observations on dyed mohair fibers (Smuts and Hunter, 1987) support this dif-
ferentiation, although a mean medulla diameter to fiber diameter ratio of 0.5 was the
critical value for undyed fibers. This definition of kemp and medullated fibers differs
from that often used by animal breeders who regard kemp fibers as medullated and
short in length. It follows that it is important, not only to keep the number of medul-
lated and kemp fibers to a minimum in the raw fleece, but also to be able to accurately
measure the proportion, so as to avoid using fibers with an unacceptable level of
medullation in certain end-uses, and to remove medullated fiber during dehairing,
carding, and combing.
Low temperature dyeing of cashmere results in less cuticle damage and a higher
tensile strength and elongation compared with higher temperature dyeing of cashmere
(Li et al., 2012). Cuticle damage of cashmere was greater with dark color dyeing and
tensile strength was lower compared with lighter color dyeing. Villarroel (1959)
concluded that the greater scaliness and the ortho-para cortical structure of Huacaya
alpaca suggest that Huacaya fiber may uptake dye better than Suri alpaca fiber but
this was not supported by Atav and T€ urkmen (2015) who found that dye uptake in
wool exceeded that of Suri fiber and Huacaya had the slowest dye uptake. Some of
these differences between fibers may be related to differences in the MFD of dyelots
as dye uptake is affected by MFD (Sch€ afer, 1994).

4.5 Sources of further information

Information on rare animal fibers is scattered in scientific journals, conference pro-
ceedings, and books. Often articles with useful information do not have appropriate
titles or key words to help locate specific data on fibers such as mohair or alpaca.
Many of the sources for further information provided in the chapter on wool also
contain articles or information on rare animal fibers. In recent years more research
on these fibers has been conducted in China and South America but the articles
have not been translated from Chinese or Spanish and are also difficult to locate.
Some conference proceedings are now only published for participants and so have
restricted availability. Much information on rare animal fibers is regarded as intellec-
tual property and is not published or publically available. The following resources pro-
vide more detailed reviews of many aspects of the production, processing, and textile
performance of various rare animal fibers.
1. Watkins P, Buxton A: Luxury Fibres, The Economist Intelligence Unit Special Report No.
2633, London, 1992, Business International.
2. Hunter L: Mohair: a Review of its Properties, Processing and Applications, Port Elizabeth,
1993, CSIR.
3. Hunter L: Mohair, cashmere and other animal hair fibres, In Kozlowski RM, editors: Hand-
book of natural fibres, Types, properties and factors affecting breeding and cultivation
(vol 1). Oxford, 2012, Woodhead, pp. 196e290.