US1719349A - Process for producing soap - Google Patents

Description

Patented July '2,

UNITED STATES PATENT OFFICE.

ADOLF WELTER, OF DKEIRINGWERKE, GERMANY.

ITROC ESS FOR PRODUCING SOAP.

This invention relates to processes for producing soap and more particularly durable soaps made by the milling process that do not change through influences of the air or 2 weather.

Efl'ortshave long been made to produce soaps that will keep indefinitely, that do not become unsightly when stored for long periods, whose weight does not change appreciably and which retain their original shape even in the tropics. The only soaps that will meet these requirements are the soaps made by the milling process; they are formed or cut into strips by being passed through pairs of rolls and then pressed into cakes. These soaps will keep for practically any length of time because they have a high content of fatty acid and a low content ofwater. Theonly known method of producing them, apart from the compressing of pure, non-hydrous,

powdered soap, has consisted hitherto in milling. In the milling process liquid high grade grain soap is first solidified, and then cu't'into slices or rolled into bands so as to make it present as large a surface as possible in the ensuing drying process. Although this drying process has recently been greatly improved by the use of ingeniously designed devices it still requires an amount of heat,

time and labor that is high in proportion to the value of the soap obtained. After the content of water has been reduced by this. known method to such an extent that the content offatty acid is about 80% the hard soap is capable of being milled. The highest content of water at which the milling is pos sible at all is about 14 to 15% (see Schrauth,

- Medikamentose Seifen 1914, page 30).

Inpractice it is, however, not advisable 1:0

s to the content of fatty acid this must not be lower than 75% and the most favorable content for milling is 7980%. Now I have found that, if the water in a hydrous soap is partly or completely substituted by bicarbonate of sodium, it is possible to make easily millable and durable soaps even if the content of fatty acid is as low as 60 to 75%. The only process known up to the present by which such soaps containing bicarbonate of sodium can be made cheaply consists in allowing fatty acids that are free of neutral Drawing. Application fileii June 2a, 1926, Serial is. 119,225, and in Germany m s, 1925.

most one molecule of soda is used the followmg equation will hold:

' RCOOH+Na,GO

RCOONa+NaHCO Now it has been found that, if fatty acids free of neutral fat as described are made to react on a maximum of one molecule of soda atabout the melting temperature of the fatty acids and liquid or solid grain soap or even soappaste is added before, or even after, the sapomfication is quite complete, a soap mixture is obtained which can be easily and perfectly milled and which has all the desirable properties such as durability, uniformity of composition, immutability of weight and shape. Quite contrary to expectation this millability of the soap mixture was found to exist even when its content of fatty acid dropped to 60%,"and even then rigorous conditions could be maintained in the method of operation and imposed on the quality of the final product. It is, therefore, possible to produce high grade or grain soaps in this manner whose composition corresponds to that of ordinary grain soapbut which greatly surpass it in respect to external appearance and durability. My novel process has, however, further advantages which will now be gone into.

It is well known that in milling grain soap the palm kernel or cocoanut oil content can only be up to 15% if 20% is exceeded trouble ensues when milling. My' aforedescribed process, however, makes it possible not only'to greatly increase the content of cocoanut or palm kernel oil, but it even renders it possible to use this oil alone, which is extremely important as far as the solubility, foam forming qualities and the utility of the soap in seawater is concerned.

It is to be particularly noted that the aforedescribed process supercedes by far all hitherto known processes in regard to economy and simplicity and that it enables a large production to be achieved even with a small plant. Just as important is the fact that it enables marketable, nice-looking soap to be made from the prepared fatty acids in one to two hours,- whereas the time re uired with known processes even with a per ect plant was several days. My novel process also enables a part of the soda to be replaced by crystallized sodium carbonate (washing soda) or by potash and permits of the use of resin. Furthermore fat solvents such as hydrocarbon bodies, for example naphtha, kerosene, or benzol, hydro-naphthaline, hydro-phenol, carbon-tetraohloride or the like may be used in the first stage of saponification or mixed with grain soap or soap paste to obtain milled soaps with a content of fat solvents.

Example 1. 1000 kgs. of palm kernel oil fatty acid or cocoanut oil fatty acid, containing more than 99% of free fatty acid, are mixed with 360 kgs. of water-free sodium carbonate. This gives a uniform substance which saponifies after a while by spontaneous heatin Before the process of saponification is en ed and before the substance has completely solidified, 700 to 800 kgs. of liquid grain soap, made from tallow or bone fat, is added. By stirring or mixing these ingredients an almost homogeneous soap is obtained in a short time which after one hour can be milled in a milling machine into ribbons. These ribbons can be formed immediately, or after they have been stored for a short period, into bars by a plodder or compressor and then cut into cakes or tablets.

Example 2.

substance is a thin liquid and perfectl .homogeneous. After a short while it becomes warm and hardens, its temperature rising to 60 to 65 C. The saponification is complete in a few hours and the substance is then soluble in distilled water at a temperaure of fectly uniform and whose exterior does not differ in the least from the usual fine soap ribbons. These ribbons can be easily plodded, cut, and pressed, and their durability is in no wise inferiorto that of the finest soaps.

I claim A a process for producing air-resisting moulded soap consisting in mixing commercial fatty acids at about their melting point with a quantity of alkali carbonate free from water, sufiicient to saponify up to twice the quantity of fatty acids present, and after saponification, admixing grain soap there with and thereupon subjecting the product thus obtained to the milling process.

In testimony whereof I have afiixed my signature.

ADOLF WELTER.