Study Set Content:
Federal regulation in 1978 that banned the use of () in hairsprays brought about a drastic change in the technology of aerosol hairspray
chlorofluorocarbons
New propellants had to be evaluated and formulations developed to accommodate their different
Properties
The hydrocarbon gases, such as ()()() have been found to generate the most consistent hairspray pattern, being at the same time compatible with alcohol and current hairspray resins
propane, butane, and isobutane
n 1990, both California and New York introduced o the concept of() placing strict limits on allowable VOC content in hair spray
volatile organic component (VOC)
s defined as any organic compound having between 1 and 12 carbon atoms
VOC
he VOC restrictions also affect the non-aerosol hairsprays where the () is both the resin solvent and propellant
ethanol
The earliest recorded methodology of hair waving can be traced to () who curled their hair with mud and then dried it in the hot sun.
Egyptians
The elaborate coiffures of Roman women relied on prototypes of the
curling iron
Then, with the advances of the Middle Ages, hair virtually disappeared and did not make its reemergence until the time of the
Renaissance
The immediate objective of waving is to impart to hair a () configuration that is different from what the hair exhibits in its native form.
¨ Each hair has a geometry that is the result of processes of () and () that transforms a viscous mixture of proteins into strong, resilient, and rigid keratin fiber.
durable, keratinization, follicular extrusion
¨ In principle, waving can be viewed as a combination of reversal and a stepwise () of these processes, as it entails softening of keratin, molding it to a desired shape, and annealing the newly imparted geometry. ¨ The underlying mechanism of waving is, thus, essentially molecular and involves manipulation of physicochemical interactions that () the keratin structure
restaging, stabilize
European, American, and large segments of the Asian markets are dominated today by the formulations based on
thioglycolic acid (TGA) and its derivative.
The popularity of TGA stems from several factors. The long history of use has built an impressive evidence of adequate medical ()
¨ High () of TGA to various formulation types that
provided markedly different end benefits coupled with performance reliability and a low price all contributed to its success.
safety., adaptability
The unpleasant () of TGA has remained it most perceptible drawback. Although some progress has been made in the fragrancing of TGA-based lotions, the results so far are at best mediocre
¨ Conventional waving lotions contain () TGA adjusted to pH ()
odor, 0.5 to 0.8M, 9.1 to 9.5.
The neutralizing base can be ()()(), or a mixture thereof.
¨ () appears to be more effective than the other bases in facilitating diffusion of TGA through hair.
ammonia, alkanol amines, sodium carbonate
Ammonia
¨ It is also preferred over nonvolatile amines because it escapes during processing and the resultant drop in pH reduces the activity of the lotion with time and thus minimizes the danger of ().
overprocessing
Over the years, several TGA derivatives (primarily amides and esters) have been tried, but as of now, only one ()(GMTG)—is of practical importance and used in so-called acid waves.
—glyceryl monothioglycollate
This is somewhat compensated for by less hair damage. To increase the efficacy of GMTG, the waving process is often carried out with the aid of
Heat
() as a permanent setting agent, has found wide application in the wool industry (pleating, lustering, flat setting) well ahead of TGA on account of its effectiveness and lack of odor.
¨ The rapid rise of()products appeared initially to spell demise for conventional TGA formulations.
Sulfite,,
Readily consumer- perceptible attributes, such as lack of () and low () damage, combined with the then preference for softer hairstyles greatly favored sulfite systems.
odor, hair
