Improvements in Solutions for Waterproofing Fibres and Fabrics.
Year: 1898

page_text: COMPLETE SPECIFICATION.
Improvements in Solutions for Waterproofing Fibres and Fabrics.
We, CARL OTTO WEBER, of Heathfield, Crumpsall, Manchester, Chemist, and
TOM TAYLOR, of the Royal Exchange, Manchester, Consulting Engineer, do hereby
declare the nature of this invention and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :-
The improvements relate to waterproofing solutions for waterproofing fibres and
fabrics, and have for object greater efficiency both with regard to the waterproofing
of vegetable and animal fibres than obtains with the solutions at present in use.
We have found that waterproofing solutions in which aluminium tannate forms
the waterproofing constituent are either unsuitable for their purpose or produce
inferior results, when these solutions contain any readily soluble salt or constituent
which, after evaporation or drying down of the solution remains readily soluble or
hygroscopic.
We find calcium sulphate is the exception to this rule.
Moreover, if aluminium sulphate forms the non-waterproofing impurity of
waterproofing solutions, such solutions, owing to the strongly acid character of
aluminium sulphate are liable to cause the fibre of the treated fabrics to become
tender, and to affect deleteriously many of the dyes and colours employed in the
dyeing and printing of textile yarns and fabrics.
In order, therefore, to increase the efficiency of waterproofing solutions of the
above named type, and more particularly in order to render them applicable to the
waterproofing of vegetable fibres and fabrics, as also for the purpose of avoiding a
detrimental action of the solutions upon dyes and colours, they should be prepared
by the interaction of either (1) aluminium sulphate and lead acetate, or
(2) aluminium sulphate and calcium acetate in the quantities or proportions
expressed by the following equations :-

page_text: copious precipitate occurs at once, leaving the resulting solution very poor in
tannic acid, and, consequently, deficient in waterproofing power.
We have found that this waste of tannic acid can be avoided and much more
efficient solutions be obtained by adding to the comparatively concentrated solution
of aluminium acetate the tannic acid in a state of high dilution.
To carry out our improvements we therefore prepare our solutions in the following
mauner:-
According to equation (1) we dissolve 3-6 lbs. of aluminium sulphate in 2.5
gallons of water; and 6.15 lbs. of lead acetate in 2.5 gallons of water.
These cold solutions are mixed together, when a precipitate of lead
sulphate is produced, which we separate from the solution of the aluminium
acetate by filtration.
To this clear solution we then add a solution of 0.14 lbs. of tannic acid in 5 gallons
of water.
According to equation (2) we dissolve 3-6 lbs. of aluminium sulphate in 2.5 gallons
of water, and 2.85 lbs. of calcium acetate in 2.5 gallons of water. These cold
solutions are _mixed together, when a precipitate of calcium sulphate is
produced which we separate from the solution of the aluminium acetate by
filtration.
To this clear solution we then also add a solution of 0.14 lbs. of tannic acid in
5 gallons of water.
The quantities of water employed in the preparation of the above solutions may
be varied within very wide limits, according to the concentration or waterproofing
strength the solutions are desired to possess. Solutions prepared in this manner are
free from every detrimental impurity and are bighly efficient for waterproofing
vegetable fibres and fabrics, while at the same time, on animal fibres and fabrics
they yield results greatly superior to those obtainable with the solutions at present
in use.
Instead of adding in the preparation of the above named solutions the tannic
acid as above described, we may add a solution of 0.14 lbs. tannic acid and from
3 to 4-6 lbs. of crystallised sodium carbonate in 5 gallons of water in this manner
we obtain a precipitate which by filtering and pressing can be brought into a paste or
pulp of any desired consistency, which will keep indefinitely in this condition, and which
at any time by the addition of water and acetic acid can be again brought into a
solution ready for waterproofing; or we may obtain the same result by dissolving
3-6 lbs of aluminium sulphate in 2.5 gallons of water, and adding to this solution
a solution of 0.14 lbs. of tannic acid and 4.6 lbs. of crystallised sodium carbonate in
5 gallons of water; the resulting precipitate being finished and prepared for use as
stated above.
Lastly, we desire to point out that solutions possessing the waterproofing
properties of those above described may also be prepared by substituting for the
lead acetate used in the above formulae the chemically equivalent quantities of
lead nitrate, i.e.: for each 1 lb. of lead acetate we may substitute 0.87 lb. of lead
nitrate.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
:-
1. The preparation of waterproofing solutions in which aluminium tannate forms
the waterproofing constituent; by means of the particular method involving the use
of tannic acid in a state of high dilution, and in manner substantially as herein
described.
2. The preparation of waterproofing solutions in which aluminium tannate forms
the waterproofing constituent, by means of the intermediary paste or pulp
of the particular character and produced in manner substantially as herein
described.

page_text: 3. The preparation of waterproofing solutions in which aluminium tannate forms
the waterproofing constituent, by means of the particular methods and in manner
substantially as herein described.
Dated this 5th dow of Ontabo 1000
WILLIAM GADD, C.E.,
64, Barton Arcade, Manchester, Agent for Applicant.