Powdered soap 90 lbs. Sodium perborate 10 "
The perborate should be added when the powder is perfectly dry or it loses its bleaching properties.
Soap powder, 20 per cent. fat. Cocoanut oil fatty acids 25 lbs. Olein 25 " Bone fat 70 " Soda lye, 30 degs. B. 90 " Water 150 " Ammonium carbonate 125 "
Soap powder, 10 per cent. fat. Cocoanut oil fatty acids 20 lbs. Olein 10 " Bone fat 20 " Soda lye, 30 degs. B. 30 " Water 175 " Ammonium carbonate 175 "
Light or fluffy powders containing 35-45% moisture can be made in two ways. The first method requiring a minimum equipment is to mix the powder and sal soda in a mixer, allow it to stand in frames for a week to crystallize or spread it on the floor for a few hours to dry and then grinding it.
The continuous method finishes the powder in a few minutes and with a minimum amount of labor. By this process the various ingredients, soap, soda ash solution, etc., are measured, run by gravity into the mixer, mixed and the molten mass run over the crystallizer or chilling rolls thru which either cold water or brine is pumped. From the roll the powder is scraped off clean by a knife, passes to a screen which sends the tailings to a grinder, falls into a storage bin from whence it is weighed and packed by an automatic weighing machine into cartons made up in most cases by another machine. Due to the large percentage of moisture contained in these soap powders the carton is generally wrapped in wax paper to aid in the prevention of the escape of moisture.
Scouring powders are very similar to soap powders and differ only in the filler used. We have already considered these fillers under scouring soap, from which they do not differ materially. They are usually insoluble in water to aid in scouring. The mixer used for substances of this kind in incorporating the soap and alkali must be of strong construction.
Scouring soaps resemble soap powders very closely in their composition, in that they are a combination of soap and filling material. Since more lather is required from a scouring soap than in soap powders, a cocoanut oil soap is generally used. The usual filling material used is silex. The greatest difficulty in the manufacture of scouring soap is the cracking of the finished cake. This is usually due to the incorporation of too great an amount of filler, or too high a percentage of moisture.