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Chemical Reaction: Controlled Release

By: Steve Herman
Posted: March 5, 2008, from the March 2008 issue of GCI Magazine.

“Any sufficiently advanced technology is indistinguishable from magic.”    
—Arthur C. Clarke

Active ingredients are the engines that propel treatment products. They are frequently unstable and require customized methods of protection, and, if they are to work, they must be delivered to the right place in active form. The basic challenge is to put something where it doesn’t naturally want to be and ensure it survives intrinsically in hostile conditions. There are many options for controlled release and targeted delivery, and new ones are developed regularly.

The history of encapsulation can be traced as far back as 1927, when capsules were spray-dried with oil-gum acacia coatings, but the real breakout occurred in 1955, when the National Cash Register Company (NCR) received a patent for the process of microencapsulation. The NCR filled its capsules with liquid, and over a period of time and under certain conditions, the capsules would break open, dispensing the liquid.

The manufacture of carbon-free carbon paper was the first commercial application. Using microencapsulated ink and by placing two sheets of paper together, a writer or typist only had to apply pressure on one paper to duplicate what was written or typed onto the other. Now that everyone has computers and printers, it is difficult to appreciate the magnitude of this invention, but it was
a great advance.

More important to the evolution of the fragrance industry, microencapsulation led to the creation of scratch-and-sniff technology, but for a different use than advertising a personal fragrance. The Dayton Power & Light Company was the first company to utilize this technology, sending scratch-and-sniff cards to its customers so that they might distinguish the smell of natural gas.