Improvements in and relating to the Manufacture of Soap.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in and relating to the Manufacture of Soap.
I, WILHELM RÖDIGER, of Magdeburg, in the Empire of Germany, Soap Mann-
facturer, 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 a process of manufacturing hard resin soap and hard resin
fat soap containing a preponderating quantity of resin. The said process is based
upon the fact that resinate of soda, by the incorporation of dehydrating agents, such
as anhydrous carbonate of soda (soda-ash), and by stirring the mass obtained so that
its molecules are not allowed to group themselves spontaneously, can be transformed
into a permanent hard hydrate, such a quantity of the dehydrating agent being
caused to act that it will remain sufficiently unsaturated to offer resistance to the
re-attraction, by the hydrate of the resinate of soda formed, of the water which it has
taken up, in consequence of which a state of tension of the molecules will be produced
which renders the hard hydrate of the resinate of soda in the soap stable.
Resinate of soda shows an uncommonly varying behaviour towards water, and it is
attributable to the want of knowledge of the underlying causes and conditions that
the production of "hard resin soap” (pure resinato of soda) and "hard resin fat-
soup" (resinate of soda) combined with fat soap containing a preponderating quantity
of resin has heretofore been impossible for the soap-maker.
My investigations have disclosed that the constitution of pine resin is extremely
variable; that the behaviour of resinate of soda towards water arises from the varying
constitution of the resin; that the quantity of water capable of being taken up and
taken up by the resinate of soda is composed of two parts which must be clearly
distinguished and kept apart, one part being bound as constitutional water and, as
such, enters into the constitution of resinate of soda, whilst the other part (which 1
term saturating water) is not in such a fixed chemical relation, yet is held with great
energy by the resinate of soda; and that the resinate of soda not only binds various
quantities of constitutional water and beyond that takes up various quantities of
saturating water, but also tends to retain both these different quantities of water with
varying energy, or to attract them from other substances containing water.
The primary conditions on which the present process depends are as follows:
(1) The constitutional water contained in the resinate of soda undergoing the
trentiment must not be attacked by the dehydrating agent (soda ash) placed by the
side of the said resinate, for if this be done the resinate of soda will so completely loso
its capability of forming a hard hydrate, the production of which is the object of the
improved process, that a mass will be obtained which is, and will remain smeary.
Accordingly the resinate of soda must contain an excess of water beyond the limit of
its constitutional water, and only this excess must be acted upon but to such an extent
that a strong tendency towards re-saturation is created.
(2) The agent (soda ash) acting upon the resinate of soda by dehydration must not
become saturated by the water it takes up from the resinate of soda, but must receive
only such a quantity of water that it will retain a sufficient power of attracting water
in order to counteract the re-attraction of the water hy the resinate of soda, and
preserve in both substances the tendency toward further saturation.
(3) The molecules of the resulting mass must be deprived of their freedom of
motion so that they cannot group themselves at will.
(4) The peculiarity of the soap manufactured by the improved process, of in-
separably cementing, during the slow setting, with the substances used for moulding
by reason of its viscosity, and of rendering any mechanical division into small pieces
impossible after the final setting on account of its hardness, makes it imperative that

page_text: the hardening, that is to say, the action of the dehydrating agent, shall be effected in
a short time, for the purpose of enabling the soap to be moulded in small forms and
obtain with sufficient quickness so much solidity that it can be removed from the
forms before it inseparably adheres to the latter.
According to the constitution of the pine-resin which is used for the production of
the resinate of soda to be treated, the minimum quantity of water which the resinate
of soda must contain for carrying the process into practice, that is to say, the
constitutional water plus the water which is to be exposed to the attack of the
dehydrating agent, amounts to hetween twenty and forty-five per cent. This minimum
proportion of water must be determined by experiments.
The aforesaid minimum quantity of water determined by experiments must be
exceeded only if the attraction of the water by the resin-soap is overpowering. In the
latter case a moderate increase in the proportion of water is attended by a diminution
of the percentage of soda. Any useless increase in the quantity of water will other-
wise result in an increase in the percentage of soda, and therefore in a deterioration of
the product. If the resinate of soda proceeds from its production with less than the
necessary minimum proportion of water this proportion must be established by the
addition of a suitable quantity of water.
The percentage of anhydrous carbonate of soda (soda ash) to be used changes
between seven and a half and fifty per cent., and depends upon the quantity of the
constitutional water in the resinate of soda and the energy with which the same is
retained as well as upon the quantity of the saturating wator in the resinate of soda
and the energy with which it is retained therein. Resins which retain their saturating
water less energetically require a smaller percentage, and vice versa. Furthermore, in
many cases where resinate of soda which takes up water very readily proceeds from its
preparation with a very small proportion of saturating water the high percentage of soda
ash for breaking its resistance can be considerably reduced by the introduction of water,
as by the production of a higher degree of saturation the tendency of the resinate of soda
to attract water is diminished. The addition of from ten to fifteen per cent. of water
is in such cases sufficient to enable a reduction of the addition of soda by from twenty
to thirty per cent. Moreover, in many resins the percentage of soda ash otherwise
necessary can be decreased by from twenty to thirty per cent. by heating the mixture
to between sixty and seventy degrees centigrade.
It may happen that if the heating is carried too far, say, to between eighty and
ninety degrees centigrade, a soft mass is obtained. In this case the latter is allowed
to stand and cool, and in the course of a few days will become quite hard, eventually
after suppressing the spontaneous grouping of the molecules by kneading, stirring, or
the like. This phenomenon may be explained by the fact that under the action of the
great heat the carbonate of soda also attacks the constitutional water of the resinate of
soda, that however during the cooling the resinate of soda, the constitutional water of
which has been reduced, takes up water with such energy that it will again draw
water from the carbonate of soda during the cooling until after a sufficient saturation
the two substances will balance each other as regards their dehydrating action, whilst
the tendency of both substances to further attract water is active. Upon this fact is
based a modification of the process as hereinafter described.
By reason of the absolute impossibility to examine pine resin as to the properties to be
taken into account the above stated conditions must in every instance be determined
before. the treatment by making a trial with the resinate of soda prepared from this
resin.
The duration of the action of the soda-ash depends upon the stubbornness with
which the resinate of soda tends to retain its saturating water. There are resins
which yield to the action of the soda-ush in a few hours-resins which set readily;
but there are also many resins which require days and even weeks-resins which set
badly; and there are finally resins which do not yield at all to the attack of soda-ash
unless special measures be taken. The resins which set with great difficulty and
great stubbornness are usually recognized by the fact that when soda-ash is added to
the resinate of soda a decrease of temperature will occur, whilst in the case of resins

page_text: The behaviour
during the salting-out of the resinate of soda also affords a test inasmuch as resinate
of soda which it is more difficult to salt out will present more stubbornness against
dehydration than that which can be salted out with greater facility. This behaviour
accounts for the varying statements in the technical literature as regards the possibility
and impossibility of separating the resinate of soda from its solutions by sodium
chloride.
which set readily at least no decrease of temperature will ensue.
To resins which set with less facility about five per cent. of sodium chloride is ndiled
which is dissolved in the resinate of soda; by this means the latter is rendered so
easily accessible to the action of soda-ash that it can be worked within twenty-four
hours into soap which will be ready for use. In case the addition of sodium chloride
does not produce its above-stated effect the temperature is increased instead, according
to the quantity to be treated, to between sixty and seventy degrees Centigrade, for
resins that set with great difficulty to between seventy and eighty degrees Centigrade,
at which it is kept for some time, thereby rendering it also possible to perform the
treatment within twenty-four hours. With quite stubborn resins the object in view
is realized by the combined employment of the above mentioned increase of temperature
and the addition of sodium chloride.
As regards the suppression of the freedom of movement of the molecules, it will
partially take place of itself in the case of resinate of soda which sets readily, and
also when assisted by sodium chloride, for in this case such a thick plastic mass is
produced at once or in a short time that there will be neither time nor possibility for
the molecules to group themselves and the comple destruction of the power of motion
which has remained in the material, will be performed by the rapid moulding which
in this case is possible or necessary.
In the case of resin soap the resistance of which to the action of soda ash must
first be overcome by the employment of heat a very liquid mass is obtained which
becomes only gradually thicker and even after the cooling forms quite a soft smeary
paste, for the molecules retain so much freedom of motion that the hard hydrate
cannot be formed. This freedom of motion is destroyed either by repeatedly stirring
the material during the cooling to perfect stiffness, or by thoroughly kneading the
same after the cooling, thus compelling the grouping of the molecules.
I have already referred to the peculiar fact that rosinate of soda, the constitutional
water in which is attacked, is capable of withdrawing water from hydrous soun.
The capacity of resinate of soda, which is not even saturated by its constitutional
water, to withdraw water from hydrous carbonate of soda which is not saturated by
the water contained therein leads to a modification of the process according to which
the formation of the hard hydrate is effected by causing a reciprocal action between
resin-soap, the quantity of water in which has been or is reduced below that of the
constitutional water, and the quantity of soda crystals corresponding to the conditions
of the retention of water as determined by previous experiments. The action which
takes place is the same as above stated, that is to say in the first place the resin soap
which is not saturated as to the constitutional water it contains, withdraws water from
the soda crystals until the formation of hydrate takes place, and then are in reciprocal
action unsaturated soda crystals, namely a dohydrating substance, and the hard
hydrate of the resinate of soda, namely also a dehydrating substance, which substances
by reason of their tendency to dehydrate each other, now produce and maintain the
tension of the molecules which is necessary for rendering the hard hydrate stable.
The same process can also be used for the manufacture of resin fat-soap especially
that which contains a great proportion of resin, but the following differences must be
observed. A higher temperature is required, because owing to the quantity of fat
the mass becomes very plastic at the coinmencement of the action of the so.in and is
therefore inaccessible to the subtile action at a mean temperature. However, the
more the percentage of resin is raised, the more the temperatures stated for pure resin-
soap will take effect. In presence of only small quantities of fat the soap behaves
exactly like pure resin soap. When the proportion of resin amounts to from seventy
five to ninety per cent. the remarkable phenomenon appears that the soap possesses a

page_text: higher capacity for retaining water and therefore a greater minimum quantity of water
than the resinate of soda by itself.
Pure fat soap produced according to this process is unsuitable for use; the tension
produced in it by the process is so great that the soap breaks up in the water into
small pieces during the washing. The withdrawal of the water by the soda in the
case of pure fat-soap is so sudden and energetic that it is industrially impossible to
complete the mixing of soap and soda before the soap which is dehydrated by the
soda becomes dry and then solidifies even in the hot state, thereby losing its cohesion
at least partially. The presence of resin in the soap in the first place retards the
action of the soda; in the second place the soap is liquid enough, even when the action
of the soda takes place, not to lose the cohesion. For soap containing up to fifty parts of
resin and fifty parts of fat the present process is however useless, because under those
conditions hard soap can be produced without making use of the same, and further-
more because it is directly deleterious, for on the one hand the existing hardness of
such soap will not be increased by small quantities of soda, whereas on the other hand
this existing hardness may possibly be diminished by the incorporation of soda, if
the resin used has a great affinity to water. In order to effect in soap containing
up to equal parts of fat and resin an appreciable increase in the hardness by means of
soda it becomes necessary in many cases to augment the percentage of water, thus
causing a deterioration, and to employ such a high percentage of soda that the soap
undergoes a complete change of its character for while soap containing a pre-
ponderating quantity of resin obtains an increasing toughness as the proportion of
resin is increased even when the hardness of stone bas been reached, and will
consequently always preserve its toughness in washing; soap containing a pre-
ponderating quantity of fat becomes shorter and shorter as the proportion of soda
which corresponds to an increasing hardness is raised; thus it loses its suppleness and
does not wash smoothly so that when it is rubbed on the washing will carry the latter
away. This process is accordingly used only for the production of hard fat-resin-soap
containing a preponderating quantity of resin. It is an eminently characteristic
feature of this process that the special properties of the resinate of soda which have
heretofore rendered its employment either by itself, or, forming a predominant
percentage, together with fat soap impossible, are a primary necessity for obtaining a
good and serviceable product.
The improved process of obtaining hard soap in case pure resin is treated is as
follows:-
Having regard to the varying properties of the resinate of soda, as great a quantity
of resin as possible is dissolved in caustic lye in order to obtain in this manner as
uniform a raw material as circumstances will permit. As most of the resins in the
resinate of sola require a higher proportion of water than results in their separation
by sodium chloride (salting-out) and as such a separation would in very many cases
present great difficulties, the separation is entirely dispensed with, and a solution just
saturated with soda is prepared by dissolving in a hot state in about forty parts of soda-
lye of thirty-eight degroes Baumé (about twenty parts of water) a hundred parts of
resin. If in a preliminary test the proportion of the water contained in this solution
of resin proves too small it is augmented. As in most cases sodium chloride is used
for the regulation of the setting, the augmentation of the proportion of water can be
effected by salt water. Now in order that as uniform a product as possible may
always be obtained it is well to establish the necessary uniformity in the action of the
carbonate of soda, whenever this may be expedient, not by an increase or a decrease
in the percentage of the latter, but by an increased or a decreased temperature
during the mixing operation. If for instance in the case of a dissolved resin a pro-
portion of ten per cent. of carbonate of soda is appropriate for obtaining a mass which
hardens rapidly whilst another does not harden in the desired manner, the proportion
of soda is not raised, but the mixing is effected at a higher temperature. Inversely,
too rapid action is retarded by lowering the temperature. Only if the differences in
the temperature do not prove effectual, and a change in the proportion of water does
not ensure the desired effect it will be expedient to increase or diminish the mean

page_text: percentage of soda. The resin soap is mixed with the soda by stirring, but the
stirring is not interrupted after the mixing has terminated; in order to prevent from
the beginning a spontaneous grouping of the molecules, and, dependent thereon, a
retardation of the process. As soon as the mass commences to thicken it is put in
small forms holding, say, 200 lbs. and continually stirred until the mass hardens
completely.
The time which is necessary for this purpose varies between a few minutes for
resins which set roadily and at most 45 minutes for resins which set badly (regulated
by sodium chloride and an increased temperature). The iron parts of the form are
then separated while yet in a warm state from the soap through the medium of a wire,
the soap being likewise cut when it is still in a warm state, and the pieces thus obtained
are ready for the market directly after the cooling.
The manufacture of resin fat-soap containing a preponderating proportion of resin
is effected in a similar manner. Resin and fat are simply dissolved to form a so-called
soap-paste. When after a preliminary trial the necessary minimum proportion
of water has been regulated, an appropriate quantity of carbonate of soda is mixed
therewith, the process being further conducted as described in the case of pure resin-
soap, the only difference being that the use of sodium chloride is avoided for
correcting the stubbornness of the setting, especially when the soap contains a large
quantity of fat, because under these circumstances the soap easily becomes crumbly
through the sodium chloride. If therefore a correction in the setting is necessary
this is produced by increasing the temperature, and, in difficult cases, by raising this
temperature for a longer time, by which means the setting is in most cases effected
with the same percentage of soda.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what
I claim is
First: The process of manufacturing hard resin-soap (hard resinate of soda),
which consists in producing a hard hydrate of the resinate of soda by the incorporation
of anhydrous carbonate of soda with resinate of soda, and, when a thin liquid is
formed, by stirring the same, and in promoting the binding of the excess of water
contained in the resinate of soda by the carbonate of soda, either by increasing the
temperature to about eighty degrees Centigrade, or by adding about five per cent. of
sodium chloride, or by the simultaneous employment of both means, as described.
Second-The modification of this process for the purpose of treating resins that
do not contain the necessary quantity of constitutional water, which consists in causing
the formation of the hard hydrate of the resinate of soda by adding water or by
employing soda crystals, the quantities of which must be determined by experiment,
as described.
Third-The employment of the two modifications of the same process for the
manufacture of resin fat-soap, whose acids bound to soda consist of more than fifty
per cent. of resinous acid, as described.
AL!
1000