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MANUFACTURING COMMERCIAL
SOAPS
Scents
set soaps apart from the crowd. Our Cold Process Soap Oils are perfect for
scenting.
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 he traditional way to make soap is by the kettle process. What is called a kettle
in the soap industry is a steel tank standing three stories high, with steam
coils in the bottom for heating. These kettles are large -- large enough to
handle several hundred thousand pounds of material at one time. The basic
ingredients for making soap are the same ones that have always been used: fats
and alkali. The fats are primarily tallow and coconut oil, and the alkali is
sodium hydroxide or caustic. These ingredients are added to the kettle and when
boiled under controlled conditions, react to form soap and glycerine. To
separate these, salt is added, which brings the soap to the top, leaving the
glycerine in the water bottom layer. The glycerine is removed and purified. It
serves many useful purposes. The soap that is left is processed further to
remove impurities and to ensure high quality.
While an excellent job of soap making can be done with kettles, in about 1940,
engineers and chemists developed a radically different method of making soap.
The new method offered real advantages over the kettle method. With it, soap
could be made by a continuous process rather than batch by batch. The new
continuous process made soap in six hours, whereas it took about a week by
kettle boiling. This made it possible to have greater control over the quality
of the finished product with less variation in quality from one week to the
next.
In the continuous method, the fats are first divided into fatty acids and
glycerine by a process called hydrolysis. What we call a hydrolyzer is a
slender, stainless steel tube about as big around as a barrel and eighty feet
high. Water, under high pressure and temperature, is pumped into the column at
the top, while hot fat is pumped in at the bottom. In the hydrolyzer, fat splits
into fatty acid (taken off at the top of the column) and into glycerine (drawn
off at the bottom with the water). The fatty acids are purified by distillation
in the same way you would make distilled water and are then mixed in a
continuous process with exactly the right amount of alkali to convert them into
soap.
When the first step in soap making is complete, whether it is done by kettle
boiling or by the continuous process, the result is a product that is called neat
soap. This is a thick liquid composed of two-thirds actual or real soap and
one-third water. This is then processed further into the finished products with
which you are familiar.
MAKING NEAT SOAP
he old process for making bars -- and it is still used somewhat today -- is
relatively simple. Hot neat soap, with which ingredients such as perfume
have been mixed, is poured into molds (or frames) and allowed to harden. When
the sides of the frame are removed, a cake of soap weighing some thousand pounds
is left. This is cut into slabs which are then cut into bar size.
Today a much superior process is used. Warm soap is mixed in high speed
equipment. In this equipment, the warm soap is whipped to a creamy consistency
and cooled in a machine called a freezer, which works much the same as an ice
cream making machine. Out of the machine is extruded an endless oblong of soap.
This is cut into bar sizes and stored briefly to allow some hardening. The bars
are then stamped and wrapped.
MAKING MILLED BARS
he word milled refers
to the fact that during processing the product goes through several sets of
heavy rolls or mills which mix and knead it. Because of the milling operation,
the finished bar lathers better and has generally improved performance,
especially in cool water. The milling operation is also the way in which
fragrant perfumes are incorporated into the cold product mixture. If perfume
were mixed into it while warm, many of the volatile scents would evaporate.
After the milling operation, the product mixture is pressed into a smooth
cylinder which is extruded continuously. This is cut into bar sizes, stamped,
and wrapped.
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