Soap Cold process

Soft Soaps.—Those differ from ihe hard s oapB in having potassa in place of soda as their alkaline baae. They arc all more or less pasty or gelatinous and they may be made either by the boiling or cold process. Of the soft soaps used in perfumery, that known as fig soap is, however, the only one that is boiled. 

A cold process with solid caustic soda or austic potash allows an accurate approach at home. The following parts by weight can be used for 10 parts solid austic soda, or 14 parts austic potash, dissolved in 20 parts hot water 72 parts beef tallow OR 73 parts lard OR 75 parts olive oil OR 71 parts palm oil. Gendy melt the fat, if solid. The two liquids are best mixed at around 40 C, mixing too warm or at uneven tempertures are common errors. Pour the fat then the caustic soda into a suitable vessel and stir or shake vigorously. Mixed well the two liquids should not separate, if they do they must be reshaken or stirred. After a week the soap can be tested to see if it produces suds. Test for excess alkalinity with indicator paper. 

In the preparation of soap by the cold process the fat is treated with a strong aqueous solution of the exact amount of alkali required to saponify it. The mixture is well stirred, and heated a few minutes until reaction begins. The heat generated by saponification is sufficient to carry it on after it is once started. At the end of several days the reaction is complete. Soap prepared in this way contains all the glycerin formed and any excess of fat or alkali which may result from incomplete saponification or the incorrect mixing of the substances used. It is apt to turn yellow and become rancid. 

Soaps are colored by adding to them small amounts of copperas, ultra-marine, or other pigment. Transparent soaps are made by dissolving a common soap in alcohol and distilling off the latter from the decanted solution until the residue is obtained as a clear transparent jelly, which is finally carefully dried in moulds. The addition of glycerol and alcohol or a solution of cane sugar to cold-process soaps, renders them more or less transparent. 

Eawes s System.—One of the most ingenious practical attempts to modify the ordinary system of soap-making was that devised by Mr. William Hawes, a gentleman who had long been connected with the soap trade, and was indeed a member of one of the largest and most enter prising firms in London. The process is well known as the COLD PROCESS, and is thus described by the inventor ... 

The adoption of the cold process in this country has not, we believe, extended much beyond the limits oi very small operations, such as toilet-soap making, for example. Indeed, the difficulty of obtaining leys sufficiently concentrated, without evaporation, would, to some extent, stand in the way of its extended application. At the present time, however, when soap-makers are supplied with caustic soda in a solid state, which renders ic... 

For maMng small quantities of Soap by the cold process, the ley should have a density of about 36 B. This may be obtained either by evaporating strong new caustic ley prepared in the ordinary way, or by dissolving commercial caustic soda in water until the required strength is reached. 

When soap made by the cold process has been in the frame for about five hours, a considerable augmentation of i ts temperature takes place, owing to the chemical reaction of its constituents, whereby a more perfect combination is effected. In order to favour this reaction, the frame should be dosely covered so soon as it has been filled with... 

In makiug coloured soaps by the cold process, it is recommended to add the colouring matter to the fatty materials before the ley is poured in, by which it becomes ore thoroughly mixed. 

This soap is made of select materials by the cold process, and er beiug made is allowed a few days to dry before melting. The musk and ambergris have to be added to the grease some weeks before frequently melting aud stirring. 

It is well known that tallow and similar soaps, when dried, are freely soluble in alcohol, and that the solution, when eyaporated to expel the spirit, leayes the soap as a trami lucent mass, which, on cooling, forms the weU-known transparent soap. The same result may, howeyer, be obtained in a greater or lesser degree with some soaps prepared by the cold process this is especially the case with castor-oil soda soap, either by the addition of a little spirit of wine or glycerine. The some result may also obtained by mixing sugar or petroleum with the mass. 

B) Treatment of Fat with Definite Amount of Alkali and no Separation of Waste Lye.—Cold-process soap is a type of this class, and its method of production is based upon the characteristic property which the glycerides of the-lower fatty acids (members of the cocoa-nut -oil class) possess of readily combining with a strong caustic soda solution at a low temperature, and evolving sufficient heat to complete the saponification. 

Although it is possible, with care, to produce neutral soaps of good appearance and firm touch by this method, cold-process soaps are very liable to contain both free alkali and unsaponified fat, and have now fallen considerably into disrepute. 

Cheaper qualities of transparent soaps are made by the cold process with or without the aid of alcohol and castor oil, and with the assistance of glycerinci or cane-sugar. 

Classification of Soaps—Direct combination of Patty Acids with Alkali— Cold Process Soaps—Saponification under Increased or Diminished Pressure—Soft Soap—Marine. Soap—Hydrated Soaps, Smooth and Marbled — Pasting or Saponification — Graining Out — Boiling on... 

Uses Cosurfactant for skin and hair care prods., esp. transparent prods, and cold processing (baby shampoos, conditioners, shampoos, shower gels, baby baths, foam baths, liq. soaps, cleansing gels and lotions, shaving prods.) reduces irritancy of other raw materials increases vise. has moisturizing and refatting props. improves foam consistency... 

A glass surface to be silvered by a ing-on process should be cleaned with soap and water or detergents. For metallizing with platinum, gold and palladiiun, improved results are sometimes obtained with glass which has been stored when, after cleaning, it is immersed in 5 per cent acetic acid (cold) for six hours. The special preparation is then applied. If necessary it is mixed before use with a suitable thinner. The preparation is allowed to dry this may be accelerated by warm air. Dust should not be allowed to settle on the surface before firing. 

Soaps bv the Cold Procesb.—All the foregoing soaps are made by boiling the fat stock with alkali hut toilet Boap may also be made extemporaneously without much heat and ihe so-called little pan process. Many of the French and American perfumers manufacture their soaps in that way. The lies are necessarily very strong, and should be of 66° Twaddell. Cold soaps are very white, and also very hard, as they do not contain any excess of water.. ... 

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