IV

Olive oil (yellow) 1000 Soda lye, 37 per cent. B. 500

V

Olive oil 90 or Palm kernel } 10 Cochin or cocoanut oil } 10 Lye, 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 (BLUE MOTTLED).

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 quant.i.ty 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 l.u.s.trous with the steam escaping 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.

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 circ.u.mstances 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 const.i.tuent 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 ma.s.s 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.

COLD MADE TRANSPARENT 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:

Tallow 193-1/2 lbs.

Cochin Cocoanut Oil 169-1/2 "

Castor Oil 89-1/2 "

Soda Ash 7-3/4 "

Soda Lye, 36 degs. B. 256 "

Sugar (Cane) 198 "

Alcohol 126 "

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 ma.s.s 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 ma.s.s 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 circ.u.mstances should any soap be allowed to remain above the surface of the ma.s.s 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 sc.r.a.ps 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 transparent soap 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 Tallow 134 lbs.

Cochin Cocoanut Oil 88 "

Castor Oil 20 "

W. W. Rosin 7 "

Cane Sugar 64 "

Water 32 "

Glycerine 34 "

Soda Lye, 38 degs. B. 135 "

Alcohol 16 gal.

II.

Tallow 211 lbs.

Cochin Cocoanut Oil 185 "

Castor Oil 97-1/2 "

Soda Ash 8-1/2 "

Water 106 "

Soda Lye, 38 degs. B. 279 "

Sugar 216 "

Alcohol 137 "

III.

Castor Oil 60 lbs.

Cochin Cocoanut Oil 195 "

Tallow 120 "

Alcohol 115 "

Sugar 90 "

Water 53 "

Glycerine 53 "

Soda Lye, 38 degs. B. 205-1/2 "

IV.