GT 50 is a faintly yellow liquid with typical aldehyde
odour. The product is stable below pH 9.0, whilst with
more strongly alkaline reaction, particularly at
elevated temperature, polymerization occurs.
GT 50 is compatible with mineral tanning agents, pickle
acids and neutral salts in all proportions. It can,
however, react with vegetable tannins and synthetic
tanning agents based on phenol and with amines.
GT 50 has good tanning properties within a wide pH
range. Its astringency rises appreciably with increasing
alkalinity of the tan liquor. Good exhaustion of tan
liquor can be obtained by bringing the pH to 5-6; short
liquors and elevated temperatures promote exhaustion as
it is used in self tannage, Jkgan GT 50 produces
leathers with full handle and a yellowish color. The
shrinking temperature of the resultant leather normally
lies above 80 C. In comparison to formaldehyde, Jkgan GT
50 gives fuller and softer leathers which are more
resilient to alkalis.
GT 50 can be used as pretanning agent in vegetable
tannage. Thus, case-hardening later on is avoided and
fixation of tannins is improved. The product can also be
used to advantage as retanning agent; it improves the
alkali resistance of vegetable tanned leather and
reduces its water permeability appreciably.
mineral tannage, Jkgan GT 50 can be applied together
with mineral tanning agents, because it does no reach
with them. Since the fixation of Jkgan GT 50 – like
other aldehyde tanning agents – is effected via the
basic groups of skin protein and that of the mineral
tanning agents mainly via the acid groups, these
reactions supplement one another to an optimum degree.
This is manifested in an appreciable improvement of the
handle and durability of the leather (e.g. resistance to
perspiration and washing). The leathers combination
tanned in this way undergo a measurable thickness
increase, and thus allow a less amount of chrome to be
Moreover, leathers tanned with Jkgan GT 50 have good