owalce] Sulphide Cellulose for Tanning 317
The results will be found in Table 4 in which each value represents
the average of three individual tests.
TABLE 4.-Calculated and analytical results on blended extracts. Results expressed
in grams per 100 cc of solution of analytical strength. (Approximately 4 g
tannin per 100 cc)
Blend No.1(2Aque- Blend No. 2 (% Blend No. 3 (%
bracho, % sul- chestnut, % sul- cutch, 4 sul-
phite No. 2) phite No. 2) phite No. 2)
(a) (b) (a) (b) (a) (b).
Total solids- - - - - _ 0. 600 0. 593 0. 607 0. 603 0.604 0. 593
Soluble solids -------------------------- .564 .576 .603 .599 .600 . 593
Insolubles _____________________________ .036 .017 .003 .003 .004 .000
Nontannins--------------------------- . 137 . 136 .213 .212 . 193 . 187
Tannins- - .427 .440 .389 .386 .406 .406
NOTE.-(a) Calculated results. (b) Analytical results.
It will be noted that the analytical results check very closely with
the calculated amounts of the different ingredients. An interesting
exception is in the case of the ordinary quebracho blend. The ana-
lytical result for insolubles was lower and for tannins higher than cal-
culated. The sulphite cellulose extract appears to have acted upon
the insolubles in the quebracho in such manner as to cause a portion
of them to be determinable as tannins. From these results it appears
that any proportional substitution of the ordinary vegetable extracts
by sulphite cellulose on the basis of tannin content will not result
in a lower tannin content for the blend than should be present as
determined by calculation.
(d) PRETANNING EXPERIMENTS.-The tanning experiments on
actual pieces of hide were carried out in the experimental tannery,
a view of which is shown in Figure 3. The first series of tests consisted
of the use of sulphite cellulose extract No. 1 as a pretannage. The
green salted steer hides used were cut into strips 8 inches wide at
right angles to the backbone. From these strips test pieces 10 inches
long were cut, and each was marked so as to identify its location on
the hide. The hide pieces were then subjected to the usual washing,
soaking, fleshing, liming, and dehairing operations, after which they
were placed in a cold water pool overnight to remove excess lime.
They were then surface delimed in a weak lactic acid bath.
The hide pieces in this condition were introduced successively into
vats of sulphite cellulose liquors containing %, 1, and 12 per cent
tannin, respectively, and allowed to remain in each vat for 24 hours.
These liquors, and those subsequently used in the yard proper, were
agitated continuously with a mechanical stirrer. The hide pieces
coming from the third sulphite liquor were completely struck through
and had a light golden grain. They were then given a yard tannage
with liquors consisting of a blend of 1 quebracho, 1 chestnut wood,
