Tallow75-90 partsCocoanut oil25-10 parts
Bleached Lagos palm oil75-80 partsCocoanut oil25-20 parts
or
Tallow30 partsPalm oil60 partsCocoanut oil10 parts
Olive oil75-90 partsCocoanut oil25-10 parts
or
Olive oil40 partsTallow40 partsCocoanut20 parts
Where a green olive oil base is desired, olive oil foots are substituted for the olive oil. Peanut oil may replace the olive oil or part of it, the same being true of sesame oil and poppy seed oil.
Palm oil50 partsOlive oil30 partsCocoanut oil20 parts
or
Palm oil20 partsOlive oil10 partsTallow50 partsCocoanut oil20 parts
It is often necessary to manufacture a cheaper grade of soap for toilet purposes to meet the demand of a certain class of trade as well as for export. To accomplish this it is of course necessary to produce a very inferior product and run down the percentage of fatty acids contained in the soaps by the addition of fillers or to use cheaper oils in manufacturing. The most simple method of filling a soap is to load it at the mill with some substance much less expensive than the soap itself. Many of the cheaper toilet soaps, however, are not milled and it is, therefore, necessary to follow out some other procedure.
Milled soaps, as has just been stated, are loaded at the mill. The consumers of cheaper toilet soaps in this country are accustomed to a milled soap and this grade of soap for home consumption is very often filled withnumerous substances, but most generally by adding starch and talc. The addition of such materials of course later exhibit themselves by imparting to the cake of soap a dead appearance. Talc is more readily detected in the soap than starch by washing with it, as talc is insoluble and imparts a roughness to the soap, like sand or pumice, as the soap wears down. It may readily be added to 20 per cent. by weight. Starch is to be preferred to talc, in loading a soap, as it is not so readily noticeable in washing. It leaves the cake itself absolutely smooth although the lather formed is more shiny. This substance may be employed to as high a percentage as one-third the weight of the soap. It is, of course, possible to cheapen the best soap base by this method and the price may be further lowered by using the less expensive oils and fats to make the soap base.
A very cheap grade of soap may be made by making a run soap and adding the filler e. g. sodium silicate in the kettle during saponification. The percentage of fatty acids may be brought down to 10 per cent., although of course a soap of this type shrinks a whole lot upon exposure.
In making a "glued up" soap the procedure is the same for making the soap itself as with a settled soap, except that the soap is finished "curd" and later filled in the crutcher. The percentage of fatty acids in a soap of this type is seldom below 50 per cent.
The method of "gluing up" a soap is best illustrated by a typical soap of this character in which the kettle is charged with the following stock.
Bleached palm oil5partsDistilled grease2"Cotton oil foots stock, 63% fatty acid1"Rosin4"
The palm oil is first run into the kettle, saponified and washed to extract any glycerine, then the rest of the fats and finally the rosin. The soap is then finished and settled as with a boiled settled soap. To assure success it is absolutely necessary that the soap settle as long a period as possible, or until the temperature is about 150 degs. F. The ideal temperature for carrying out the "gluing up" process is 140 degs. F., as at a lower temperature than this the soap is liable to cool too quickly and not be thoroughly glued up. A higher temperature than 150 degs. F. causes delay in that the soap does not properly take the filler at a higher temperature and the soap must be kept in the crutcher until the temperature drops to the right point.
The soap is run into the crutcher and the percentage of fatty acids run down to 50-55 per cent. with one of the following mixtures:
Sodium silicate, 59-1/2° B.1partPotassium carbonate, 51° B.1"
or
Sodium silicate, 59-1/2° B.1partPotassium carbonate, 51° B.1"Sodium sulfate, 28° B.1"
From 230 to 300 pounds of either of these mixtures are required for a crutcher holding 2,600 pounds of soap.
The crutching is continued until the mass is well "spiked," that is to say, a freshly broken surface of the soap, as the crutcher blade is jerked away, stands up like shattered sheets in triangular form (Δ Δ Δ), which retain their shape perfectly. When this condition is realized the soap is run into frames which are carefully crutched by hand to remove any air spaces. The surface of the soap is then smoothed down and heaped up in the center. After standing a day to contract, the surface is again leveled and asnugly-fitting board placed on the top of the soap upon which a weight is placed or upon which the workman treads and stamps until the surface is flat, thus assuring the further removal of air spaces. The soap remains in the frame from six to eight days and is then slabbed, barred and pressed by the usual method employed for soaps thus handled without milling.
In a soap of this nature no hard and fast rule can be laid down as to the quantity of solution to be used for "gluing up" or the strength of the solution. In a soap of the type described the most satisfactory appearing cake will be obtained from a soap containing 58 per cent. fatty acids. That is to say, about 8 per cent. to 10 per cent. filling solution is added per hundred pounds of soap. The filling solutions given are very satisfactory. Carbonate of soda should be avoided in connection with sodium silicate as the property of efflorescing on the surface of the finished cake after a short time will prove detrimental. To assure successful gluing up it is advisable to experiment upon a small scale to determine the exact extent to which the filling solution should be diluted. Various proportions of water are added to a certain quantity of the filled soap. After the soap has been filled in a small receptacle a sample is taken and rubbed between the fingers. If the freshly exposed surface is smooth and glossy, the filling solution is weak enough, if rough it is too strong. It is of course understood that the temperature must be correct, 140 degs. to 150 degs. F., or the soap will be rough. By this means the operator can readily judge the correct strength of his filling solution. When properly carried out a perfectly satisfactory soap is obtained.
The object of a soap which is finished "curd" or grained, is to obtain a harder piece of goods from low titer fat orto increase the percentage of fatty acids in the finished soap. This is still another method of producing a cheap grade of soap as by its adoption the cheaper oils and fats may be used to obtain a firm piece of soap.
A typical charge for curd soap is:
Red oil63partsTallow10"Rosin27"
Cotton seed foots may be employed in place of red oil and a tallow of too high titer is not suitable for this kind of soap.
The red oil and tallow are first saponified with 15 degs. B. lye, boiler pressure 80-90 pounds, 18 degs. B. lye for lower steam pressure, and two washings given to extract the glycerine. The rosin is added at the strengthening change and at the finish the soap is "pitched," that is to say, the soap is settled over night only. The next day the lyes are drawn off and a portion of the nigre pumped to another kettle which prevents later streaking of the soap. The soap is then boiled with 18 degs. B. lye as with another strengthening change under closed steam. Salt brine or "pickle," 15 degs. B. is then added and the mass boiled with closed steam until the brine reaches a density of 18 degs. B. and the kettle pumped the next day. A soap of this type requires either hand or power crutching to assure homogeneity and prevention of streaks. To obviate any air spaces it is advisable to place over the top of the frame a tightly-fitted board which is heavily weighted down. This soap is also pressed without any milling.
Comparatively little toilet soap is made by the cold or semi-boiled processes. While these are the simplestmethods of manufacturing soaps the drawbacks of using them are numerous and only in a few cases are they very extensively employed. To make a toilet soap by the cold process a combination of good grade tallow and cocoanut oil is required. It requires 50 per cent. by weight of 36 degs. B. lye to saponify a given weight of tallow and 50 per cent. of 38 degs. B. lye for cocoanut oil. The lyes are used full strength or may be reduced slightly with water and the method of procedure is the same as already given in the general directions for cold made soaps.
Cold made soaps are readily filled with sodium silicate which is added at the same time the stock is put into the crutcher. In adding the silicate it is necessary to add additional lye to that required for saponifying the fats, about 20 per cent. of 36 degs. B. lye is the proper amount. There is of course a certain amount of shrinking due to the addition of this filler and the finished cake is exceedingly hard, yet the author has seen a good looking cake of cheap soap made from as high a proportion as 420 parts of tallow to 600 parts of silicate.
Cold made soaps are usually pressed without milling, although it is readily feasible to mill a cold made soap provided it is not a filled soap such as has just been described.
Equally important as the soap itself or even to a greater extent is the perfume of a toilet soap. A prominent manufacturer recently made the statement, which is often the truth, that it makes no difference to the public what kind of soap you give them, as long as you put plenty of odor into it. The perfuming of soaps is an art in itself and a subject to be treated by one versed in this particular branch. We can only take into account the importance ofthe perfume as related to toilet soap not only, but the necessity of adding a certain proportion of the cheaper products of odoriferous nature to laundry soap to cover and disguise the odor of even this type of soap.
The price of a cake of toilet soap to a great extent depends upon the perfume, and the manufacturer should aim to give the best possible perfume for a certain price. He should not allow his personal likes or dislikes to enter into the judgment of whether an odor is good or not, but submit it to a number of persons to obtain the concensus of opinion. In giving or selling a piece of soap to the consumer, it is second nature for him to smell it, and in the great majority of cases his opinion is formed not from any quality the soap itself may have during use, but from the odor. This only emphasizes the fact that the perfume must be pleasing, not to one person, but to the majority, and many brands owe their popularity to nothing more than the enticing perfume.
Perfuming of soap is closely allied to the soap making industry, but as stated a branch in itself. It is, therefore, not our purpose to give numerous formulae of how to perfume a soap, but rather to advise to go for information to some one who thoroughly understands the characteristics of the numerous essential oils and synthetics and give positive information for the particular odor desired. Under no circumstances is it advisable to purchase a perfume already compounded, but since all perfumes are a blend of several or many essential oils and synthetics, it is a more positive assurance of obtaining what is desired, by purchasing the straight oils and blending or mixing them as one desires.
The perfume is added to a milled soap just before the milling process in the proper proportion per hundred pounds of soap. In cold made or unmilled soaps it isadded in the crutcher while the soap is still hot. By this method, of course, a proportion of the perfume is lost due to its being more or less volatile.
While much toilet soap is white or natural in color, many soaps are also artificially colored. The soap colors used for this purpose are mostly aniline dyestuffs. The price of these dyestuffs is no criterion as to their quality, as the price is usually regulated by the addition of some inert, water soluble substance like common salt or sugar.
The main properties that a dyestuff suitable for producing a colored soap should have are fastness to light and to alkali. They should further be of such a type that the color does not come off and stain a wash cloth or the hands when the soap is used and should be soluble in water. Under no circumstances is it advisable to add these in such a quantity that the lather produced in the soap is colored. It is customary to first dissolve the dye in hot water as a standardized solution. This can then be measured out in a graduate and added to the soap the same time as the perfume is put in. About one part of color to fifty parts of water is the proper proportion to obtain a perfect solution, though this is by no means fixed. In making up a solution thus it is an improvement to add to the same about one-half of one per cent. of an alkali either as the hydroxide or carbonate. Then, if there is any possibility of change of color due to alkalinity of the soap, it will exhibit itself before the color is added.
A particularly difficult shade to obtain is a purple, as there is up to the present time no purplish aniline color known which is fast to light. Very good results in soap may be obtained by mixing a fast blue, as ultramarine or cobalt blue, with a red as rhodamine or eosine.
Inasmuch as the colors for soap have been carefully tested by most of the dyestuff manufacturers, and their information, usually reliable, is open to any one desiring to know about a color for soap, it is better to depend upon their experience with colors after having satisfied one's self that a color is what it is represented for a particular shade, than to experiment with the numerous colors one's self.
Soap is often used for the conveyance of various medicants, antiseptics or other material presumably beneficial for treatment of skin diseases. While soap is an ideal medium for the carrying of such materials, it is an unfortunate condition that when incorporated with the soap, all but a very few of the numerous substances thus employed lose their medicinal properties and effectiveness for curing skin disorders, as well as any antiseptic value the substance may have. Soap is of such a nature chemically that many of the substances used for skin troubles are either entirely decomposed or altered to such an extent so as to impair their therapeutic value. Thus many of the claims made for various medicated soaps fall flat, and really have no more antiseptic or therapeutic merit than ordinary soap which in itself has certain germicidal and cleaning value.
In medicating a soap the material used for this purpose is usually added at the mill. A tallow and cocoanut oil base is best adapted for a soap of this type. The public have been educated more or less to the use of colored soap to accentuate its medicinal value, and green is undoubtedly the most popular shade. This inference, however, is by no means true for all soaps of thischaracter. Possibly the best method of arranging these soaps is briefly to outline some medicinal soaps.
The best known sulphur soaps contain anywhere from one to 20 per cent. of flowers of sulphur. Other soaps contain either organic or inorganic sulphur compounds.
The tar used in the manufacturing of tar soap is obtained by the destructive distillation of wood, the pine tar being the most extensively employed. While the different wood tars contain numerous aromatic compounds, such as phenols, phenyl oxides, terpenes and organic acids, these are present in such a slight proportion so as to render their effectiveness practically useless. It has, therefore, been tried to use these various compounds contained in the tar themselves to make tar soap really effective, yet tar is so cheap a substance that it is usually the substance used for medicating a tar soap. About 10 per cent. of tar is usually added to the soap with 2 ounces of lamp black per hundred pounds of soap.
Phenol (Carbolic Acid) is most extensively used in soaps of this kind, which are called carbolic soaps. Carbolic soaps are generally colored green and contain from 1 to 5 per cent. phenol crystals.
The cresols are also extensively used for making soaps named carbolic. These substances impart more odor to the soap and really have more disinfecting powers than phenol when incorporated with soap.
Other soaps, containing the phenol group, which are well known are resorcinol soap, salol soap, thymol soap,naphthol soap, etc. From one to five per cent of the compound after which the soap is named is usually incorporated with the soap.
Hydrogen peroxide in itself is an excellent disinfectant. It loses all its medicinal value, however, when added to the soap. To overcome this objection various metallic peroxides are added to the soap, as sodium peroxide, zinc peroxide and barium peroxide. These generate hydrogen peroxide by the addition of water. Sodium perborate is also used in peroxide soaps, as this substance is decomposed by water into hydrogen peroxide and sodium metaborate.
Mercuric chloride (corrosive sublimate) is most extensively used for the production of mercury soaps. Because of its extremely poisonous properties care should be taken in using it. Since it really eventually loses any antiseptic value in the soap through forming an insoluble mercury soap it might better be omitted entirely.
While the above mentioned soaps are probably the best known medicated soaps, there are numerous other soaps which may be classed under these kinds of soaps. Thus we have cold cream soap, which can be made by adding Russian Mineral Oil, 1 to 5 per cent., to the soap; witch hazel soap, made by the addition of extract of witch hazel; iodine soap, made by adding iodine or iodoform; formaldehyde soap, made by adding formaldehyde; tannin soaps, made by adding tannin. In fact, there have been incorporated in soap so great anumber of substances that the list might be greatly enlarged.
Medicated soaps are not only used in solid form, but in powder, paste and liquid soap as well. The only difference in a soap like those just referred to is that the medicant is incorporated with these forms of soaps as convenience directs.
A pure castile soap should be made from olive oil. This, however, is not always the case, as a number of oils as well as tallow are used to adulterate this oil to cheapen it, and there are even some soaps called castile which contain no olive oil at all. Most of the pure castile soap used in this country is imported, as it is a difficult matter for the American manufacturer to compete with the pure imported castile soap, since both labor and oil itself are so much cheaper in the vicinities of Europe where this oil is produced, that this advantage is more than compensated by the carrying and custom charges by importing the castile soap.
Castile soap may be made either by the full boiled or cold process. There are numerous grades of olive oil, and those used for soap making are denatured to lower the duty charges. Olive oil makes a hard white soap, usually sold in bars, and olive oil foots a green soap, due to the coloring matter contained in this oil.
To make a boiled castile soap, a composition of 10 per cent. Cochin cocoanut oil and 90 per cent. olive oil may be used. To cheapen this, peanut oil (Arachis oil) may entirely replace the olive oil, or about 20 per cent. of corn or soya bean oil may be added. The oils are saponified as usual in making a settled soap and to prevent rancidity the soap is boiled near the finish forsome time in the closed state with sufficient excess of alkali to give it a sharp taste, then grained with lye, the lye drawn off, closed with water and then grained with salt. This process is repeated until the desired strength is reached. The last graining should not be too great, and on the last change the soap should not be thinned out, as it will contain too great a quantity of water when slabbed.
In making a cold castile soap the usual method is pursued as already directed under cold made soap. When the soap is taken from the crutcher it is advisable, however, to keep the soap in the frame well covered to assure complete saponification. Some manufacturers use very small frames which are placed into compartments, well insulated to retain heat. Several formulae for cold made castile soaps, follow. It may be noted that some of these contain practically no olive oil.
IOlive oil2030Palm kernel674Soda lye, 35 per cent. B.1506IIOlive oil2030Cochin cocoanut oil674Soda lye, 36 per cent. B.1523Sodium Silicate82IIIPalm kernel oil1578Tallow940Olive oil7Sodium silicate, 20 per cent.190Soda lye, 36 per cent. B.1507IVOlive oil (yellow)1000Soda lye, 37 per cent. B.500VOlive oil90orPalm kernel }10Cochin or cocoanut oil }10Lye, 37 per cent. B.51
If any of the soaps containing a high proportion of cocoanut oil are boiled the soap will float. It is therefore necessary to keep the temperature as low as possible.
Eschweger soap is a colored mottled or marbled soap made to a very slight extent in this country. Inasmuch as it has been introduced to the export trade, it is made for this purpose by some manufacturers. A high percentage of cocoanut oil is usually used together with tallow and grease. About one-third of each is a typical formula. In a soap of this character the fact that cocoanut oil soap takes up a large quantity of water and salts of various kinds and is difficult to salt out is made use of. The tallow and grease are first saponified as usual, then the cocoanut oil is pumped and saponified. When the saponification is nearly completed either silicate or carbonate of soda or common salt are added to make the soap "short" so as to form the mottle. The finishing of a soap of this type can only be gained by practice and it is rather difficult to explain the exact appearance of the kettle at this stage. The surface of the soap should be bright and lustrous with the steamescaping in numerous places in rose-like formation. A sample on the trowel should have a slight sharpness to the tongue and be plastic. When the soap slides from the trowel it should break short. When the soap has reached this stage the desired coloring matter, usually ultramarine, is added to the soap either in the kettle or crutcher and the soap framed. The yield is 200-215 pounds per hundred pounds of stock.
Several modifications of this general method for Eschweger soap are used by adopting the half boiled or cold process.
Transparent soap is really not a most desirable soap for toilet purposes, as it contains an excess of free alkali. It has, nevertheless, met with public approval because of the fact it is novel in being transparent. Except for this fact very little merit can be claimed for a soap of this kind.
The transparency of soap is generally due to the presence of alcohol, sugar or glycerine in the soap when it is made. It is very essential in a soap of this character, where lightness and clearness of color are desired, that the material for making the soap be carefully selected as to color and purity. The perfumes also play an important part in the color of the soap and many of the tinctures, balsams and infusions used in perfuming soap may eventually cause trouble by spotting. If the soap is artificially colored, which is almost always the case, the dyestuffs used for this purpose should have careful attention and only those should be used which are known to resist the action of alkalis. Where rosin is used this product must be of the better grade. Distilled water is always preferable for use in transparent soap. The government permits the use of a specially denatured alcohol. This alcohol is not taxed and consists of grain (ethyl) alcohol denatured with 5 per cent. wood(methyl) alcohol. Some soapmakers prefer to use a more expensive refined methyl alcohol, but outside of adding to the cost of the soap, there is no particular advantage. The glycerine should be chemically pure. As to the oils and fats these should be low in acid and of good color. Under no circumstances should the crutcher or kettle in which the soap is made be rusty or unclean in any way. For a light soap enameled utensils are to be preferred.
To obtain transparency in soap the following general methods may be given.
1. Where the transparency is due to sugar.
2. Where alcohol and glycerine produce transparency.
3. Where (1) or (2) is supplemented by the use of castor oil.
4. Where transparency depends upon the percentage of fatty acid in a soap and the number of times the soap is milled.
Under the first method at least 25 per cent. of the charge should be cocoanut oil, the other constituent being tallow or any fat or oil capable of giving a sufficiently hard soap. The soap is boiled and finished as usual, then run to the crutcher to be mixed with a strong cane sugar solution, containing 10-20 per cent. sugar of the weight of the soap. The sugar is dissolved in its own weight of water and the solution heated to 175 degs. F. before being very slowly added to the soap. As the water evaporates, soaps of this type show spots due to the sugar thus being thrown out of solution.
Transparent soap made under the second method may be saponified as usual and consist of any good toilet base. The soap is run to the crutcher and mixed with 95 per cent. alcohol in the proportion of one part alcohol to two parts of fatty acid contained in the soap together with glycerine in the same proportion.
By the third method castor oil alone may be used to make the soap or added to any of the above bases up to 33-1/3 per cent. of the charge. If castor oil only is used, but 2 per cent. or 3 per cent. of sugar is required.
In the last method a combination of 80 per cent. tallow, very low in free acid, 20 per cent. cocoanut oil and 5 per cent. W. W. rosin is a suitable charge. The saponification and finishing is carried out as with a full boiled soap. The soap is then placed into a jacketed vessel, provided with dry-steam coils, by which the excess water is evaporated from the soap until it contains 73 per cent. fatty acids. When the thick mass reaches this stage it is framed and when cool is suitable for obtaining a semi transparency which now depends upon the number of times the soap is milled, it being, of course, inferred that no solid matter of any sort be added to the soap.
While transparent soaps may be made by the above general methods they are usually made by the semi-boiled or cold process. By this process a more satisfactory soap is obtained and it is more simple to carry out. A detailed description of this method is best and most easily given by using a typical formula.
Charge:Tallow193-1/2lbs.Cochin Cocoanut Oil169-1/2"Castor Oil89-1/2"Soda Ash7-3/4"Soda Lye, 36 degs. B.256"Sugar (Cane)198"Alcohol126"Water (Distilled)80"
To proceed, first place into a crutcher or jacketed kettle the oils and fat and heat to 140 degs. F. Then add the soda ash dissolved in about 30 pounds of the water, after which the lye is added and the mass stirred until a finger or stick run over the surface leaves an imprint. Where the soap has reached this stage, it is well covered and allowed to stand about two hours or until it bulges in the center, after which the rest of the water which should contain no lime or other mineral substance and which is preferably distilled water, is added. The sugar is then slowly shoveled in while the mass is stirring and finally the alcohol is poured in. The heat is then increased to 160 degs. F. by dry steam and the soap crutched until dissolved. Under no circumstances should any soap be allowed to remain above the surface of the mass on the sides of the mixer. This crutching operation consumes about one hour, and when finished the soap should stand in the vessel about half an hour when a small sample is taken out to cool. This sample should be clear and show an excess of alkali. If it is not clear more alcohol is added, if not of sufficient strength more lye put in until the desired condition is reached. The perfume and color are now added.
The soap is then framed and allowed to set after which it is cut, allowed to dry slightly and then pressed. To obtain a polished cake transparent soaps are often planed before pressing and after pressing polished with a soft cloth, dampened with alcohol. Instead of framing this soap, it is sometimes "tubed," that is to say, the soap from the crutcher is run into specially constructed tubes of a shape near that of the desired cake and allowed to cool, after which it is cut and pressed. All scraps are returned to the crutcher, but in so doing the soap is slightly darkened in color. It is advisable to expose a finished cake of transparentsoap to the air for some time as by so doing it becomes clearer.
Other formulae for cold made transparent soaps made as just outlined follow:
I.Bleached Tallow134lbs.Cochin Cocoanut Oil88"Castor Oil20"W. W. Rosin7"Cane Sugar64"Water32"Glycerine34"Soda Lye, 38 degs. B.135"Alcohol16gal.II.Tallow211lbs.Cochin Cocoanut Oil185"Castor Oil97-1/2"Soda Ash8-1/2"Water106"Soda Lye, 38 degs. B.279"Sugar216"Alcohol137"III.Castor Oil60lbs.Cochin Cocoanut Oil195"Tallow120"Alcohol115"Sugar90"Water53"Glycerine53"Soda Lye, 38 degs. B.205-1/2"IV.Tallow100lbs.Cochin Cocoanut Oil100"Castor Oil60"Glycerine20"Rosin, W. W.20"Sugar40"Water50"Soda Lye, 36 degs. B.164"Alcohol8gal.V.Tallow174lbs.Cocoanut Oil114"Soda Lye, 38 degs. B.170"Sugar80"Water72"Alcohol16gal.
Rosin may be added in this formula up to 20 per cent. of fats used and the tallow cut down correspondingly.
The requirements of a shaving soap are somewhat different than those of other soaps. To be a good shaving soap the lather produced therefrom must be heavy, creamy, but not gummy, and remain moist when formed on the face. The soap itself should be of a soft consistency so as to readily adhere to the face when used in stick form. It should furthermore be neutral or nearly so to prevent the alkali from smarting during shaving.
Shaving soap is made in the form of a stick, and a tablet for use in the shaving mug. Some shavers prefer to have the soap as a powder or cream, which are claimed to be more convenient methods of shaving. While a liquid shaving soap is not as well known because it has not yetbecome popular, some soap for shaving is made in this form.
Formerly shaving soap was extensively made from a charge of about 80 parts tallow and 20 parts cocoanut oil as a boiled settled soap, but either making the strengthening change with potash lye or using potash lye in saponifying the stock and graining with salt. Soaps for shaving made in this manner are very unsatisfactory, as they do not produce a sufficiently thick or lasting lather and discolor very materially upon ageing. Potassium stearate forms an ideal lather for shaving, but readily hardens and hence needs some of the softer oils, or glycerine incorporated with it to form a satisfactory soap for shaving.
The selection of materials for making a shaving soap is important. The tallow used should be white and of high titer. Cochin cocoanut oil is to be preferred to the other kinds, and the alkalis should be the best for technical use that can be purchased—76 per cent. caustic soda and 88-92 per cent. caustic potash are suitable. By the use of stearic acid it is a simple matter to reach the neutral point which can be carefully approximated.
The following are shaving soap formulae which have been found to give good satisfaction:
I.lbs.Tallow360Stearic acid40Soda lye, 41° B.147Potash lye, 34° B.87Water32Gum tragacanth1II.lbs.Tallow282Cocoanut oil60Stearic acid50Bayberry wax18Soda lye, 41° B.147Potash lye, 34° B.90Water32III.lbs.Tallow400Cocoanut oil176Stearic acid415Caustic soda, 40° B.182Caustic potash, 38° B.108
To proceed, first run into the crutcher the tallow, cocoanut oil and bayberry wax when used, and bring the temperature of the mass up to 140°-160° F. by dry steam. Then add the caustic soda lye and keep on heat with occasional mixing until it is all taken up. When this stage is reached gradually add all but about 5 per cent. of the potash lye, and complete the saponification. This point having been reached, the heat is turned off; the crutcher is run and the stearic acid, previously melted by dry steam in a lead-lined or enameled vessel, is run in in a continuous stream and the crutching continued for fifteen minutes to half an hour. Samples are taken at this time, cooled and tested by alcoholic phenolphthalein solution. If too alkaline more stearic acid is added, if too acid more potash lye from that previously reserved. After each addition of lye or stearic acid the mass is crutched from 10 to 15 minutes longer, another sample is taken, cooled and again tested. When the phenolphthalein shows a very light pink after several minutes, the soap is practically neutral, although at this point one can better judge by dissolving a sample in hot neutralized alcohol made by putting into the alcohol a few drops of phenolphthalein, and then adding weakalkali drop by drop from a burette until a slight pink, not yellow, tint is obtained, and noting the color of the solution. The solution should show a very light pink when the soap is properly neutralized. When this stage is arrived at the gum tragacanth, previously softened in water, is crutched in if it is to be added. The soap is then framed, stripped in three or four days, dried and milled.
The formulae as given are for shaving sticks, and do not readily press unless thoroughly dried. A more satisfactory result is obtained by adding at the mill 25 per cent. of white tallow base to obtain a satisfactory mug soap.
Shaving powder differs from the soaps just described in being pulverized, usually adding up to 5 per cent. starch to prevent caking. Any of the above soaps, dried bone dry, with or without the addition of tallow base make a satisfactory powder for shaving.
Shaving cream is now a very popular shaving medium due to the rapidity and convenience with which one can shave by the use of this product. Formerly shaving cream was made from the liquid oils like olive oil and a soft fat like lard, together with cocoanut oil. Now, however, most of the popular shaving creams are made from stearic acid and cocoanut oil, as a far superior product is obtained by the use of these substances. By using these a more satisfactory cream is obtained, and it is far more convenient to make. The lather also produced therefrom is more suitable for shaving, being thick, creamy and remaining moist.
A few typical formulae for shaving creams of this type are as follows: