Cleaning of hair. j. Soc. Cosmet. Chem., 32, (December 1981)

j. Soc.Cosmet. Chem.,32,437-458(December1981)

Cleaning of hair MIKLOS M. BREUER, Gillette ResearchInstitute, 1413 Research Blvd., Rockville,MD 20850?

Received June5, 1981.Presented at theAnnualMeetingof the AmericanOil Chemists' Society, New Orleans,1981.

Synopsis

Whereasthe principles of cleaningof textilematerialsarewell established, the sameis not the casefor humanhair.Cleaningof hairoccursunderconstraints whicharedifferentfrom thoseimposedon fabric laundering:requirementof short time durations;the necessityfor usingambienttemperatures; and stringenthumansafetyconsiderations with respectto the cleaningmaterialsused.Also,consumers use differentcriteriafor assessing the stateof cleanliness of hair from thoseemployedfor textiles;they depend,in additionto thequantityof the soil,on thephysico-chemical properties of sebum.In addition to the amountof soilremoved, the variousattributes of theproduct(e.g.,fragrance, color,etc.)andthe rateof hairresoilingsubsequent to shampooing alsoplayan importantpartin judgingshampoo efficacy. The resoiling ratedepends on the consistency of the sebumandon the surfacecharacteristics of hairafter shampooing, both of whichdependon the natureof the shampooingredients andtheirinteractions with hair. The gapsof knowledgethat existin the mechanisms of hair cleaningand which requirefurther research,have also been reviewed.

I.

INTRODUCTION

Humanhair has similarchemicalcomposition, physicalpropertiesand histological structure to thoseof keratinfibersusedin textilematerials (e.g.wool,mohair,etc.)(1). Nevertheless, cleaningandwashingof hairconstitute a vastlydifferentproblemthan the oneencountered in thelaundering of fabricsspunfromkeratinous yarns. When formulating a hairshampoo, certainrestrictions mustbe keptin mind:a) the cleaningcanonlybe carriedout underphysiologically acceptable temperatures, i.e.,at about 40-45øC;b) the time availablefor cleaningis relativelyshort;(5-10 minutes comparedto the 30-40 minutesthat a launderingoperationlasts);c) the detergents usedin shampoos mustmeetstringenthumansafetystandards (i.e.,low skinandlow eyeirritancy, no sensitization or toxicitypotentials, no extremepH values,etc.);andd) the fact that the criteriafor assessing the cleaningefficacyare differentfrom those usedfor measuring cleanliness of textiles. ICurrent address:The Gillette Co., PersonalCare Div., Gillette Park, Boston, MA 02106.

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438

JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS

II.

NATURE

THE

OF

SOIL

IN

HAIR

Threetypesof materials soilhair:a) oily su•,sm,,.es, .,t,, .•,- (e.g.sebum,excretedfrom the sebaceous gland,lipidsoriginatingfrom skinsurfacecells),b) proteinaceous matter (e.g. cell debrisfrom the stratumcorneumand proteinsof the sweat,etc.) and c) extraneous materials, mainlyparticulate soil(e.g.hydrocarbons, sootandmetaloxide particles,etc.)that depositfrom the pollutedenvironment and ingredients of hair groomingpreparations left behind(e.g.detergents, waxes,pomades, hairspray resin, etc.).Whereasall thesevarioussoilsplayimportantpartsin affectingthe visualand tactileperception of hairdirtiness, probablythe lipidsarethe mostimportantdueto their stickyconsistency cementingthe variousparticlesto eachotherand to the hair surface.

A. THE

SEBUM

ON

HAIR

The amountof sebumfound on the scalpand on hair at any particularmoment depends on the relativemagnitudes of two processes: a) the productionof sebumby the sebaceous glandsand b) its removal,mainlyby mechanical action,i.e. rubbing, combing,brushing,etc.).Sebumproductionhasbeenthe •',•;•* •C manydetailed investigations /2 =x The sebumoriginatesfrom the sebaceous glands-t:•t are attachedto the hair follicles(Figure 1). The sebaceous glandsproducesebumat continuousoutputs(2,4). There are someseasonalor evendaily variationsin the amountof sebumproduced (5)(Figure2)andit isgenerally accepted thathormones, in particularandrogensand estrogens (2,5), affect the productionof sebum.As the hormonalbalancechangeswith age from preadolescence to pubertyand then to

S•h-ematic Diagram•-•f HairFollicleSand Associated Slain Glands

skin surJac½

apo-pilosebaceousduct • ---•.

•,

sebaceousgt