formaldehyde - Sciencemadness Dot Org

USES OF FORMALDEHYDE 315
Other protein materials utilized in the production of formaldehyde-modified
resins and plastics include dried blood, yeast, leather waste, and vegetable
proteins such as gluten, zein, ground-nut protein, cottonseed meal,
and keratin from hoofs, horn, hah-, and feathers.
Cheap resinous products may also be produced from a wide variety of
crude protein materials. It is reported that fish meat can be converted
to a thermoplastic resin by kneading with formaldehyde in the presence of
rater and under pressure at 80° to 150°C I , A molding composition prepared
from formaldehyde and powdered animal tendons which have been
washed, pulverized, degreased, and bleached 29 is also described.
Resins from Wood Products. Lignin isolated from pulp-wood as a byproduct
of the paper industry is now utilised as a raw material for resins.
Resins of this type are sometimes modified with formaldehyde, more
commonly with phenol-formaldehyde condensates. In a process described
by Scott 81 , lignin precipitated by acidulation of the black liquor obtained
in the alkaline soda or sulfate extraction of pulp is claimed to give a useful
molding composition when dissolved in ammonia water and reacted with
formaldehyde. According to Lundback 31 , wood fiber containing lignin
can be converted to a hard, board-like product by treatment with formaldehyde
and subjection to heat and pressure. Approximately 0.1 to 10 per
cent formaldehyde (based on dry wood) is employed. In another patented
process 33 , it is stated that useful molding powders can be produced by dissolving
lignin in phenol and heating with formaldehyde or hexamethylenetetramine
in the presence of an alkaline condensing agent. Collins, Freeman
and Upright 11 report the preparation of acid-resistant resins from
lignin-cellulose by reaction with formaldehyde and phenol.
Wood flour plays an important part in the resin industry as a filler for
formaldehyde resins.
Natural tamiin-containhig materials such as quebracho wood or mimosa
bark, when finely subdivided, can be compounded with formaldehyde or
paraformaldehyde in the presence of a water-soluble plasticizer such as
glycerin to'give molding powders 23 .. The plasticizer also serves as a solvent
for the tannin, whose content in the mixture may be adjusted by adding
tannin extract or wood flour.
Pinewood pitch is reported to condense with formaldehyde solution or
paraformaldehyde to give useful resinous products-.
Resins from Polyhydroxy Compounds. Sugar, starch, cellulose, and
other high molecular weight polyhydroxy compounds may also be employed
in the preparation of numerous resinous compositions in which formaldehyde
is involved. Although they serve in many cases as fillers for other
formaldehyde resins, it is probable that in some instances they are chem-