Soap-Making Manual Part 8

Tallow 75-90 parts Cocoanut oil 25-10 parts

PALM BASE.

Bleached Lagos palm oil 75-80 parts Cocoanut oil 25-20 parts

or

Tallow 30 parts Palm oil 60 parts Cocoanut oil 10 parts

OLIVE OIL BASE (WHITE).

Olive oil 75-90 parts Cocoanut oil 25-10 parts

or

Olive oil 40 parts Tallow 40 parts Cocoanut 20 parts

Where a green olive oil base is desired, olive oil foots are subst.i.tuted 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 AND OLIVE BASE.

Palm oil 50 parts Olive oil 30 parts Cocoanut oil 20 parts

or

Palm oil 20 parts Olive oil 10 parts Tallow 50 parts Cocoanut oil 20 parts

CHEAPER TOILET SOAPS.

It is often necessary to manufacture a cheaper grade of soap for toilet purposes to meet the demand of a certain cla.s.s 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 with numerous 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.

RUN AND GLUED UP SOAPS.

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 ill.u.s.trated by a typical soap of this character in which the kettle is charged with the following stock.

Bleached palm oil 5 parts Distilled grease 2 "

Cotton oil foots stock, 63% fatty acid 1 "

Rosin 4 "

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 a.s.sure 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. 1 part Pota.s.sium carbonate, 51 B. 1 "

or

Sodium silicate, 59-1/2 B. 1 part Pota.s.sium 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 ma.s.s 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 [Transcriber's note: three triangles]), 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 s.p.a.ces. 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 a snugly-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 a.s.suring the further removal of air s.p.a.ces. 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 quant.i.ty 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 a.s.sure 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 quant.i.ty 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.

CURD SOAP.

The object of a soap which is finished "curd" or grained, is to obtain a harder piece of goods from low t.i.ter fat or to 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 oil 63 parts Tallow 10 "

Rosin 27 "

Cotton seed foots may be employed in place of red oil and a tallow of too high t.i.ter 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 ma.s.s 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 a.s.sure h.o.m.ogeneity and prevention of streaks. To obviate any air s.p.a.ces 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.

COLD MADE TOILET SOAPS.

Comparatively little toilet soap is made by the cold or semi-boiled processes. While these are the simplest methods 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.