formaldehyde - Sciencemadness Dot Org

36S
FORMALDEHYDE
itatrng bath which usually contains formaldehyde and sulfuric acid plus
sodium chloride, aluminum sulfate, or other modifying agents. An aftertreatment
may involve relatively long immersion in a formaldehyde bath
to set the fibers completely 11 . Soybean fibers are a comparatively recent
development compared with casein fibers and show considerable promise.
They are ^aid to possess a higher degree of water-repellence and a better
resistance to mold than casein fibers.
It has been reported that other protein materials may also be used as
the basis for fiber preparations. These include ground nut or castor bean
globulin 1 and keratin from hoofs, horn, hah-, etc.
Formaldehyde Treatment of Wool. The improved resistance of formaldehyde
treated wool to the action of boiling water, alkalis, alkali sulfides,
etc., may be utilized to protect wool in processes such as bleaching, dyeing,
washing, etc., which involve exposure to these agents. In a process patented
by Kann 3 * in 1905, it is stated that satisfactory resistance of woolen
fibers can be developed by treatment with formaldehyde- vapors or dilute
neutral or weakly acid solutions containing as little as 0.03 per cent formaldehyde.
Good results are reported when a hot -£ per cent formaldehyde
solution is employed.
Since formaldehyde treatment also increases the resistance of wool to
certain dyes, pattern effects may be secured by making use of this fact in
the dyeing process. Both formaldehyde and condensation products of
formaldehyde with cresol-sulfonic acid may be employed for this purpose
according to a German patent 5 . Dyed woolen fabrics have been claimed
to show greater fastness and stability after treatment with formaldehyde
alone or in combination with tannic acid 14 .
A recent patent for shrmkproofing wool 13 claims that this effect can be
secured by treating the wool with a solution containing formaldehyde and
an acid at a pH of not more than 2, drying, baking at a temperature sufficient
to complete reaction without tendering, washing, and drying. Another
process 43 recommends treating wool with a water solution containing
formaldehyde, boric acid, urea, and glycerol. It is also claimed that the
shrinkage of wool can be reduced by treatment with special formaldehyde
derivatives. Dichloromethyl ether which is produced from formaldehyde
and hydrogen chloride is reported to effect a substantial reduction in wool
shrinkage if applied to the fabric in an inert nonaqueous solvent such as
Stoddard solvent or trichloroethylene 55 .
Yakima and Shivrina 63 report- that woolen textiles may be rendered
resistant to bacterial degradation by soaking in aqueous formaldehyde,
washing and drying. Wool treated in this way stands up well on use in
paper machines. Resistance of treated samples was measured by treating
with 0,4 per cent solution of trypsin in a solution buffered to pH 8.3-8.5.