For the finishing of worsted cloth soaps high in cocoanut oil or palm kernel oil are preferred. These soaps are finished very neutral, being made as settled soaps, but given an extra wash change after strengthening strongly. They are then finished as usual and run into barrels. If framed too hot, the high percentage of cocoanut oil causes mottling, which is prevented by crutching by hand until the temperature of the soap is 140°-145° F. Some typical charges, all of which are saponified with soda lye, follow:
| I. | |
| Palm Kernel Oil | 60 parts |
| Corn Oil | 40 " |
| II. | |
| Palm Kernel Oil | 30 " |
| Red Oil (single pressed) | 70 " |
| III. | |
| Red Oil | 33-1/3 " |
| Corn Oil | 33-1/3 " |
| Cocoanut Oil or Palm Kernel Oil | 33-1/3 " |
SOAPS USED IN THE SILK INDUSTRY.
Soap is used to a very large extent in silk mills, both for degumming the raw silk and in silk dyeing. Raw silk consists of the true silk fibre known as fibroin and a gummy coating, sericin, which dulls the lustre of the silk unless removed. For this purpose a slightly alkaline olive oil foots soap is best adapted, although palm oil and peanut oil soaps are sometimes used, as well as soaps made from a combination of house grease to the extent of 30 per cent., together with red oil or straight olein soaps, both of which are artificially colored green. In using house grease, if 30 per cent. is exceeded in combination with red oil, the titer is raised to such an extent that the soap does not readily rinse from the silk nor dissolve readily. They are also not advisable because they impart a disagreeable odor to the silk.
To make a soap for this purpose from olive oil foots it is made as a settled soap, care being taken to thoroughly boil the mass on the saponification change in the closed state to assure proper saponification. The kettle is usually grained with lye and given a good wash change to remove the excess strength. The change previous to the finish should not be too heavy or too large a nigre results. The lighter the grain is, the better the finished kettle is. A yield of 150 per cent. is usually obtained. This soap is generally run to a frame, slabbed upon cooling and packed directly into wooden cases.
For silk dyeing the above soap is suitable, although any well-made soap of good odor and not rancid is useable. While soap alone is often used in the bath for silk dyeing, certain dyestuffs require the addition of acetic or sulphuric acid, which sets free the fatty acids. If these be of bad odor it is taken up by the silk and is difficult to remove. The most generally used soaps are the just mentioned olive foots soap or a soap made from a good grade red oil.
Both kinds are extensively used.
SOAPS USED FOR COTTON GOODS.
In the manufacture of cotton goods, as compared to the wool and silk industries, very much less soap is used and it is only applied to the finished fabric either to clean the cloth preparatory to dyeing or to aid in dyeing with certain colors. It is also used in calico printing. For cleansing the cloth ordinary chip soap is suitable although a more alkaline soap finished as a curd soap is an advantage in that the free alkali contained therein aids in removing the dirt and has no harmful effect on the cotton. For dyeing cotton goods or to brighten certain colors after dyeing an olive oil foots soap is most generally employed. In calico printing soap is used to wash and clear the cloth after printing. A soap for this purpose should be easily soluble in water and contain no free alkali, rosin or filler. The best soaps for use in calico printing are either an olive oil foots soap or an olein soap.