Improvements in the Manufacture of Soap.
Year: 1890

page_text: Date of Application, 9th Oct., 1890-Accepted, 22nd Aug., 1891
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Soap.
We, CLAUDE AUGUSTUS OSCAR ROSELL, residing at 1131 Ninth Street,
North-west, in the City of Washington, County of Washington, District of
Columbia, United States of America, Chemist, and JOHN CRYMES PENNIE,
residing at 1711 Corcoran Street, in the City of Washington, County of
Washington, District of Columbia, United States of America, Civil 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:-
This invention relates to the production of hard potash soap, both opaque and
transparent; and consists first in salting out potash soap to make it purer; secondly
in making a non-deliquescent potash soap suitable for toilet purposes; thirdly in
making a transparent potash soap of increased hardness.
The
It has been long known that any ordinary soft potash soap may be desiccated
so as to form a hard potash soap without suffering any discoloration.
product thus made, however, has several undesirable features which make
it objectionable in many respects and utterly unsuitable to take the place of
the soda toilet soaps. These objections are: The hard potash soap produced
by desiccation of soft potash soap is deliquescent. It will contain all the free alkali
employed in effecting a complete saponification of the fats or oils used, and it will
also contain all the impurities (such as coloring matter and nitrogenous ingredients)
of the constituent oils or fats employed in its manufacture. When it is desirable to
make a potash soap suitable for toilet purposes all of these objections should be
substantially removed. The removal of the impurities derived from the oils and
fats is of course always important, but where the soap is to be used for laundry
purposes it is not necessary that it be entirely neutral or non-deliquescent.
In order to obtain a pure, hard and non-deliquescent potash soap we proceed as
follows:
Pure fatty acid or acids, such as stearic or palmitic acid or a mixture of the two
are added to a carefully calculated quantity of caustic potash or carbonate of potash,
with water to the amount of twice to five times the weight of the fatty acid used.
The mixture is heated until saponification is effected and the soap formed is closed,
water being added from time to time, if necessary. When the saponification is
effected so that the mixture does no longer contain any free fatty acid or free
alkali and presents a perfectly closed homogeneous mass, it may then be simul-
taneously heated and agitated either in the vessel where produced or in a separate
vessel until it offers too much resistance to the stirrer blades. When it has attained
this consistence, the desiccation may be easily completed in the ordinary way until
the soap is perfectly anhydrous or dehydrated to any desired extent.
It may
afterwards be pulverized and compressed into cakes. In order to increase the
hardness of such cakes a small part of the caustic potash or carbonate of potash
used, say from five to twenty per cent., may be replaced by the corresponding
soda salt, when the soap produced will be suitable for milling and stamping in
the ordinary way, and constitutes an elegant toilet article, superior in its action
on delicate skin and textile, in general detergent qualities, and inferior in no
respect to the best existing toilet soda soap. The hardness may also be increased
by the addition of a non-deliquescent neutral or feebly-alkaline potash salt, such
as the sulphate, bi-carbonate, sulphite &c.; or the hardness may be increased
by means of an excess of fatty acid added either at the beginning or end of
saponification, the latter being the preferred mode of addition.

page_text: Stearine 2000 lbs.
Caustic potash of 60 % strength, 830 to 900 lbs.
Water, 1000 to 3000 lbs.
Potassium chloride, 350 to 1000 lbs.
If
We do not wish however, to be restricted to these particular proportions.
Although a hard and non-deliquescent toilet potash soap may be produced in
the manner just described, an additional step may with advantage be introduced.
It is difficult and expensive to obtain free fatty acids of sufficient purity; we
therefore prefer to modify one step of the process as follows: We take stearine
or palmitine, or a mixture of them, and saponify with caustic potash in the
ordinary way, using a sufficient excess of alkali to make the saponification
complete within a reasonable time. When the saponification has been effected
and the soap has been closed, we add to it chloride of potassium or some other
potash salt having the power of salting out the soap when a saturated or
sufficiently strong solution is used. Formerly it has been considered impossible
to salt out potash soap probably because in experiments to that end only a
small quantity of chloride of potassium was used. The chloride of potassium or
other potash salt may be added either in solution or in crystalline form.
chloride of potassium be used, it is best to add so much thereof that on cooling
the soap, the pan will contain solid salted out potash soap floating on the top
of the lye, and a cake of crystalline chloride of potassium at the bottom of the
lye. It is not necessary that such large proportion of chloride of potassium
should be added, but it is convenient as a sign that a sufficient quantity has been
added to effect a thorough and rapid separation. This salting out may be repeated
a sufficient number of times until the potash soap at last obtained is of the requisite
purity and neutrality. In place of the chloride of potassium there are other potash
salts that may be used, such as the acetate. In fact, the potash soap may, if
desired, be salted out first with one potash salt and subsequently with another.
it be desired to make a potash soap containing some sodium stearate or palmitate to
increase its hardness, the saponification may be effected by means of caustic potash
containing a desired proportion of caustic soda, or the salting out may be effected
by means of a suitable potash salt containing a calculated proportion of soda
salt.
If
After the salting out is completed, the desiccation and subsequent treatment is the
same as that already described.
If it be desired to make the potash soap produced transparent, it may be made so
in the manner pursued in making transparent soda soap.
If the soap produced be intended for laundry purposes, where it is not absolutely
requisite that it remain non-deliquescent, the oil or fat used may contain a
suitable proportion of oleic acid and the soap produced still be improved by
salting out.
Although the hardest form of potash soap should contain no oleic acid, free
alkali, or glycerine, yet it is evident that for the purpose of making transparent
potash soap, stearine or palmitine or a mixture of them may be saponified with
caustic potash and the products desiccated, dissolved in alcohol and finished in the
usual way, yet it is for the reasons already stated preferable first to make a hard
and non-deliquescent potash soap containing practically no glycerine, and subse-
quently to add to it any desired proportion of the latter. The hardness of the
transparent potash soaps may also be increased by the addition of a suitable
proportion of sodium palmitate or stearate or a mixture of the two.
stated the firmness of the non-transparent form of toilet potash soap may be increased
by the addition of either free fatty acid or a non-deliquescent potash salt, such as
the sulphate, nitrate, bi-carbonate, &c. The best texture of the soap is, however,
produced by the addition of a small proportion of sodium stearate as stated..
As before
In the salting out of potash soap by a suitable potash salt, such as the chloride, a

page_text: part of the salt used in salting out will be retained by the soap. This, however,
will do no harm if the salt used in salting out is non-deliquescent and neutral, or
very feebly-alkaline.
In this description by solid fatty acid is meant a fatty acid solid at ordinary
temperature, such as stearic and palmitic and some other equivalent and more rarely
occurring fatty acids, and by liquid fatty acid is meant oleic acid and the lower
acids of the fatty acid series, having approximately the same melting point as oleic
acid.
As before stated, when a hard potash soap or a mixture of potash soap and soda
soap is desired, especially adapted for laundry purposes, and which needs not be non-
deliquescent, such a product may be obtained in a pure form by saponifying any
ordinary fat or oil or mixture thereof and subsequently salting out the soap desired,
whether it be potash soap or a mixture of potash soap and soda soap, in the manner
above described. The product thus obtained will contain oleic acid but will be
distinguished from any similar products by its freedom from glycerine, which will be
separated by the step of salting out and retained in the sub-lye..
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:
1. The addition to closed potash soap of a suitable potash salt, whereby the
potash soap is salted out as described.
2. Salting out potash soap by means of a non-deliquescent potash salt, as set
forth.
3. Salting out potash soap by means of potassium chloride, as set forth.
4. Salting out mixed potash and soda soap by means of a suitable potash salt, as
set forth.
૧.
5. Salting out a mixed potash and soda soap, by means of a non-deliquescent
potash salt, as set forth.
6. Salting out a mixed potash and soda soap by means of potassium chloride as
set forth.
7. Salting out a mixed potash and soda soap by adding to potash soap potassium
chloride containing a suitable proportion of sodium chloride as set forth.
8. The method of drying potash soap which consists in simultaneously heating
and agitating closed potash soap until a mass is obtained which on cooling acquires
the requisite hardness.
9. A cake of hard, non-deliquescent pressed soap consisting of solid fatty acid or
acids and potash.
10. A cake of hard, non-deliquescent, milled and pressed soap consisting of solid
fatty acid or acids and potash.
11. A non-deliquescent hard soap consisting of a mixture of solid fatty acids and
potash.
12. A non-deliquescent hard soap consisting of potash and excess of solid fatty
acid or acids.
13. A non-deliquescent hard soap consisting of potash, solid fatty acid or acids
and a non-deliquescent neutral or feebly alkaline potash salt.
14. A non-deliquescent hard soap consisting of potash, soda and solid fatty acid
or acids.
15. A transparent hard potash soap, practically free of oleic acid as set
forth.
16. A transpareat hard soap containing potash and soda and practically free of
oleic acid as set forth.
17. A hard soap consisting of fatty acid or acids, potash and soda and practically
free of glycerine, as described.
18. A hard soap consisting of solid and liquid fatty acid or acids and potash, and
practically free of glycerine, as set forth.

page_text: 19. Salting out a mixed potash and soda soap by adding to potash soap, a
suitable potash salt containing a requisite proportion of a suitable soda salt as
described.
Signed at Washington, D.C., this 18th day of September 1890.
CLAUDE AUGUSTUS OSCAR ROSELL.
JOHN CRYMES PENNIE.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicants.