Part 5 (1/2)

In carrying out this method upon a large scale, large sueNeanderthaldoroteerNeanderthalJosephine quant.i.ties of carbon dioxide are formed during the boiling of the soap, which replaces a quant.i.ty of the air contained therein. The kettle room should therefore be well ventilated, allowing for a large inflow of fresh air from out of doors.

CHAPTER IV

Cla.s.sification of Soaps.

In considering the many different varieties of soaps, their cla.s.sification is purely an arbitrary one. No definite plan can be outlined for any particular brand to be manufactured nor can any very sharp distinction be drawn between the many soaps of different properties which are designated by various names. It is really a question to what use a soap is to be put, and at what price it may be sold. There is, of course, a difference in the appearance, form and color, and then there are soaps of special kinds, such as floating soaps, transparent soaps, liquid soaps, etc., yet in the ultimate sense they are closely allied, because they are all the same chemical compound, varying only in their being a potash or soda soap, and in the fatty acids which enter into combination with these alkalis. Thus we can take a combination of tallow and cocoanut oil and make a great many presumably different soaps by combining these substances with caustic soda, by different methods of manufacture and by incorporating various other ingredients, as air, to form a floating soap, alcohol to make a transparent soap, dyestuffs to give a different color, etc., but essentially it is the same definite compound.

The manufacturer can best judge the brand of soaps he desires to manufacture, and much of his success depends upon the name, package, shape, color or perfume of a cake of soap. It is the consumer whom he must please and many of the large selling brands upon the market today owe their success to the above mentioned details. The great majority of consumers of soap know very little concerning soap, except the fact that it washes or has a pleasant odor or looks pretty, and the manufacturer of soap must study these phases of the subject even more carefully than the making of the soap itself.

For a matter of convenience we will cla.s.sify soap under three general divisions:

I. Laundry soaps, including chip soaps, soap powders and scouring soaps.

II. Toilet soaps, including floating soap, castile soap, liquid soap, shaving soap, etc.

III. Textile soaps.

LAUNDRY SOAP.

The most popular household soap is laundry soap. A tremendous amount of this soap is consumed each day in this country, and it is by far manufactured in larger quant.i.ties than any other soap. It is also a soap which must be sold cheaper than any other soap that enters the home.

The consumers of laundry soap have been educated to use a full boiled settled rosin soap and to make a good article at a price this method should be carried out, as it is the one most advisable to use. The composition of the fats entering into the soap depends upon the market price of these, and it is not advisable to keep to one formula in the manufacture of laundry soap, but rather to adjust the various fatty ingredients to obtain the desired results with the cheapest material that can be purchased. It is impossible to use a good grade of fats and make a profit upon laundry soap at the price at which it must be retailed. The manufacturer of this grade of soap must look to the by-product, glycerine, for his profit and he is fortunate indeed if he realizes the entire benefit of this and still produces a superior piece of laundry soap.

SEMI-BOILED LAUNDRY SOAPS.

It is advantageous at times to make a laundry soap by a method other than the full boiled settled soap procedure as previously outlined. This is especially the condition in making a naphtha soap, in which is incorporated naphtha, which is very volatile and some of the well known manufacturers of this cla.s.s of soap have adopted this process entirely.

A laundry soap containing rosin cannot be advantageously made by the cold process, as the soap thus made grains during saponification and drops a portion of the lye and filling materials. By making a semi-boiled soap this objection is overcome. The half boiled process differs from the cold process by uniting the fats and alkalis at a higher temperature.

To carry out this process the following formulae have been found by experience to give satisfactory results.

I. lbs.

Tallow 100 Rosin 60 Soda Lye, 36 B. 80

II.

Tallow 100 Rosin 60 Silicate of Soda 25 Soda Lye, 36 B. 85

III.

Tallow 100 Rosin 100 Lye, 36 B. 105 Silicate of Soda 25 Sal Soda Solution 20

In any of these formulas the sodium silicate (40 B.) may be increased to the same proportion as the fats used. By so doing, however, twenty pounds of 36 B. lye must be added for every hundred pounds of silicate additional to that indicated or in other words, for every pound of silicate added 20 per cent. by weight of 36 B. lye must be put into the mixture. The rosin may also be replaced by a previously made rosin soap.

To make a semi-boiled soap, using any of the above formulae, first melt the rosin with all or part of the fat, as rosin when melted alone readily decomposes. When the mixture is at 150 F. run it into the crutcher and add the lye. Turn on sufficient dry steam to keep the temperature of the soap at about 150 F. in the winter or 130 F. in summer. After the ma.s.s has been mixed for half an hour, by continuously crutching the soap it will at first thicken, then grain and it may again become thick before it becomes smooth. When the ma.s.s is perfectly smooth and h.o.m.ogeneous drop into a frame and crutch in the frame by hand to prevent streaking. After standing the required length of time the soap is finished into cakes as usual.

SETTLED ROSIN SOAP.

Settled rosin soaps are made from tallow, grease, cottonseed oil, bleached palm oils of the lower grades, corn oil, soya bean oil, arachis oil, distilled garbage grease, cottonseed foots or fatty acids together with an addition of rosin, varying from 24 per cent. to 60 per cent. of the fatty acids which should t.i.ter from 28 to 35. A t.i.ter lower than 28 will prevent the finished kettle of soap from being capable of later taking up the filling materials. As has already been stated under hardened oils, these being very much higher in t.i.ter allow a greater percentage of rosin to be added. Thus hardened fish oils and cottonseed oil are gradually being more extensively employed in soaps of this character.