000001
`
`IPR20l3-00509
`
`UNILEVER EXHIBIT 1045
`
`UNILEVER EXHIBIT 1045
`UNILEVER VS. PROCTOR & GAMBLE
`IPR2013-00509
`
`UNILEVER VS. PROCTOR & GAMBLE
`
`

`
`air and
`Halr Care
`
`edited by
`
`Dale H. Johnson
`
`Helene Curtis, Inc.
`
`Rolling Meadows, Iuinois
`
`3, edited by
`
`tions, edited
`
`I Approach,
`
`edited by P.
`
`rd by James
`
`and Carl B.
`
`ry Vwlliam C.
`
`L. Riersche!
`
`Jacts, edited
`
`rermann and
`
`D‘ by Dennis
`
`cts. Howard
`
`Aspects.
`as J. Lowe,
`
`IS: Principles
`
`HARCEL
`
`m MARCEL DEKKER, INC.
`
`DIKKER
`
`N1~:w YORK - BASEL
`
`000002
`000002
`
`

`
`Library of Congress Catalogingdn-Publication Data
`
`Hair and hair care I edited by Dale H. Johnson.
`p.
`cm — (Cosmetic science and technology ; 1'!)
`Includes index.
`
`ISBN 0-8247-9365-X (alk. paper)
`1. Hair preparations. 2. Hair—-Care and hygiene. 3. Hair
`preparations industry—United States.
`1. Johnson, Dale H.
`II. Series: Cosmetic science and technology series ; v. 17.
`'I'I‘969.I-I343
`1997
`646.?'24-——dc2l
`
`97-4018
`CIP
`
`The publisher offers discounts on this book when ordered in bulk quantities. For
`more information, write to Special SaIes.fProfessional Marketing at the address
`below.
`'
`
`This book is printed on acid-free paper.
`
`Copyright © 1997 by MARCEL DEKKER, INC. Ail Rights Reserved.
`
`Neither this book not any part may by reproduced or transmitted in any form or
`by any means, electronic or mechanical, including photocopying, microfilming,
`and recording, or by any information storage and retrieval system, without
`permission in writing from the publisher.
`
`MARCEL DEKKER, INC.
`2'70 Madison Avenue, New York, New York E0016
`
`
`
`About the Set
`
`The Cosmetic Science an
`sion of a broad range if
`and technoloB}'- The 5F“‘
`or edited volumes with
`academia. and the S_°"°"
`The aim of this set
`technol08Y- T0p1_<=S an’: ‘*1
`chemistry. PhY5'°9v_b_'°°
`safety. 6ffiC3CY» ‘°’”°“y’
`and polymer chemiStl')'.
`toxicology 311 P133’ 3 ml
`There is little con
`
`mulations Y5‘-l“‘“'°d f°r
`tured. Products range fl
`lipsticks. "331 F-'°1i5h°5 3
`over the counter produc
`crobiai soaps, and 21011}?
`COSITIBILIC and toll!
`
`000003
`000003
`
`

`
`Conditioning of Hair
`
`Myra A. Hoshowski
`Helene Curtis, inc, Chicago, iiii'noi's
`
`I.
`
`INTRODUCTION
`
`Hair that is conditioned is in a proper and healthy state. Healthy hair looks
`shiny, feels soft, is easy to comb and style, and retains body and bounce.
`If hair were left alone, it would tend to remain in a conditioned state. The
`
`cuticle, or outer layer of hair would remain intact and a layer of sebum would
`provide the hair with protection from mechanical friction. However, a buildup
`of sebum gives the hair an undesirable appearance. During the process of
`cleansing, wet hair is vulnerable to mechanical abrasion and therefore becomes
`damaged. Chemical treatments used to permanently alter hair’s color and curl
`further weaken and damage hair.
`It
`is the job of Conditioners to help counteract these negative effects.
`When conditioning agents are applied to the hair, frictional force is reduced and
`combing becomes easier,
`thus maintaining the hair in its proper and healthy
`state. Some conditioning agents may even penetrate the hair fiber to actually re-
`store damaged hair to a healthy condition.
`There is no single perfect conditioning agent, but rather a multitude of
`conditioning agents available to the formulating scientist. An endless number of
`combinations of these conditioning agents can be used in conditioners. By uti-
`lizing the technical information that is provided about the conditioning agents
`and examining the examples of formulations, the formulator can use this chap-
`ter as a starting point for developing a balanced conditioner which meets the
`needs of his or her target market segments.
`
`000004
`000004
`
`65
`
`

`
`66
`
`Hoshowski
`
`ll. HOW HAlR STRUCTURE RELATES TO ITS CONDITION
`
`The hair shaft is composed of two major morphological regions, the cortex and
`the cuticle. The cortex’s function is to provide mechanical properties such as
`strength to the hair fiber. The cuticle is the chemically resistant outer layer
`responsible for protecting the cortex. Six to 10 layers thick, the cuticle resists
`physical and chemical degradation by forces such as friction, pulling, bending,
`and ultraviolet radiation. I-Iair’s appealing visual and tactile characteristics are
`due to the cuticle’s arrangement. Cuticle cells arranged in overlapping scales lie
`flat, reflecting light and allowing each strand to slide smoothly against its adja-
`cent neighbors. Even though the cuticle is remarkably resistant, it is not imper-
`vious to attack and will break down from repeated exposure to the environment,
`physical manipulation during grooming, and chemical alteration. This greatly
`simplified overview of hair structure is provided to show how hair’s structure
`relates to its condition. Robbins (1) and Chapters 1 and 2 of this volume explain
`the morphology of hair in greater detail.
`
`III. HAIR DAMAGE AND ITS CAUSES
`
`Numerous researchers have studied the way in which physical and chemical
`processes damage hair by observing how hair loses its color and luster, becomes
`more harsh, stiff, weak, brittle, and flyaway.
`
`A. Grooming
`
`Gould and Sneath (2) compared the cross sections of proximal, or root portions
`of the hair to the distal, or end portions of the hair before and after repeated
`shampooings. They found that damage was limited to the cuticle and increased
`from the proximal to the distal portion of the hair fiber.
`Kelly and Robinson (3) studied the effect of the normal grooming process
`of shampooing, towel drying, wet combing, and wet brushing on the cuticle.
`During the shampooing stage of the grooming process, hair becomes tangled in
`knots. Wet hair has a lower resistance to abrasion than dry hair, while at the
`
`same time, the wet hair is subjected to very strong-abrasive forces. Although
`shampooing and towel drying alone can abrade the cuticle, wet combing and
`particularly wet brushing inflicts much greater damage. Cuticle layers are lost
`at a rate of 1
`to 2.5 cuticles per 50 treatments. On the basis of this rate, if the
`grooming procedure is undertaken only twice per week, the entire cuticle is re-
`moved in only 14 to 60 months leading to subsequent splitting of the cortex.
`Sandhu et al. (4) developed a sensitive colorimetric method to quantify
`the amount of hair protein fragments abraded during combing. Chemically
`treated hair exhibits greater protein loss than untreated hair.
`
`000005
`
`

`
`Conditioning
`
`67
`
`Kamath et al. (5) used tensile tests and scanning electron microscopy
`studies to show how negroid hair is particularly susceptible to damage during
`the grooming process because of its unique configuration. Frequent twists along
`the fiber axis with random reversals in direction lead to stress concentrations
`during the tensile deformation experienced when combing or brushing the hair.
`
`3. Climatic Exposure
`. \
`.
`.
`.
`.
`.
`Tolgyesi (6) describes the effects of cumulative climatic exposure, or weather-
`ing on hair as it ages. Hair grows approximately 6 inches per year until
`it
`reaches a genetically predetermined length of about 3 feet. Since the distal por-
`tion of the hair fibers have been exposed longer than the proximal portion, the
`damaging effects of weathering are progressively more noticeable as one pro~
`ceeds from the proximal portion to the distal portion of the hair fiber. In the
`initial stages of weathering, hair becomes discolored, followed by cuticle loss,
`fiber splitting, and finally, breakage.
`Dubief (7) used xenon lamp solar simulators in the laboratory to mimic
`hair damage caused by natural sunlight. Dubief found that damp conditions are
`necessary to induce the structural alteration and photobleaching of hair.
`'
`
`C. Chlorine and Salt Water
`
`Fair and Gupta (8) discuss the chemical interaction of hair with the chlorine
`that is found in pool water. Chlorine weakens hair by forming distinctive All-
`worden sacs or bubbles of dissolved protein which burst through the cuticle.
`These sacs tend to catch on combs and brushes, forming splits and cracks in
`the cuticle. While salt does not interact chemically with hair, salt that is left be-
`hind on hair after swimming in the sea dries into hard crystals which cause me-
`chanical abrasion of the cuticle.
`
`D. Heat Styling
`
`Wolfram (9) has shown that hot rollers which employ moderate heat, typically
`less than 120°C, do not damage hair even after 50 repeated cycles. Hair break-
`age may occur, though, from careless winding and unwinding of the hair from
`the rollers. Other heat-styling appliances such as curling irons, crimpers, and
`straightening irons operate at much hotter temperatures and can exceed l'?5°C.
`These excessive temperatures reduce hair’s tensile strength after repeated use,
`resulting in a weakened fiber (10).
`
`E. Chemical Agents
`
`A variety of chemical agents are utilized to alter hair‘s natural color or texture.
`Permanent colors and bleaches use hydrogen peroxide to oxidize hair‘s natural
`pigment, called melanin, and replace it with synthetic dyes resulting in a new
`
`000006
`000006
`
`

`
`68
`
`Hoshowsl-ti
`
`more fashionable color. Corbett (ll,l2) provides a detailed explanation of the per-
`manent hair coloring and bleaching processes. Even though hydrogen peroxide
`weakens hair by cleaving disulfide bonds, Jachowicz (13) suggests that the most
`important aspect of the damaging effect of the coloring process is the deposition
`of dye particles on the hair’s surface, considerably increasing the frictional force
`and, consequently, the combing force. Bleaching is a more aggressive oxidative
`process which damages hair further, decreasing the crosslink density and provid-
`ing additional anionic sites on the hair in the form of dysteic acid residues.
`Permanent waves rearrange hair’s natural curl by breaking and reforming
`the disulfide linkages into a new. more desirable and usually more curly style,
`although this process is also used to relax curl. Wickett (14) has shown that per-
`manent waving has a profound effect on the mechanical behavior of hair,
`in-
`cluding swelling, length contraction under no load, stress relaxation under load,
`and changes in elastic properties. Permanent waving reduces hair’s tensile
`strength, leading to breakage during combing or brushing.
`The end result of all of these physical and chemical processes may be a
`weakened hair fiber with uplifted cuticle scales. Uplifted cuticle and tom cuti-
`cle edges increase the frictional forces between the hair fibers and the comb or
`brush, resulting in triboelectric charging of the hair causing a phenomenon
`
`known as flyaway (15).
`Each of these physical and chemical processes will act synergystically with
`one another to inflict ever increasing damage upon the hair fiber. It becomes the
`job of a conditioner to provide hair with a protective coating that prevents this
`damage from occurring by lowering frictional
`forces and elirriinating static
`charge. Therapeutic or deep conditioners may actually deposit materials which
`become absorbed by the cortex and replace some of what has been lost.
`
`IV. CONDITIONING AGENTS
`
`A. Definition of a Conditioning Agent
`
`Nearly all hair care products are formulated to maintain or restore hair to its
`natural healthy condition by incorporating one or more conditioning agents.
`
`ldson (16) defines conditioning agents as additives which enhance the appear-
`ance, feel, fullness, lubricity, reflectance, and general manageability of hair. The
`second edition of the CTFA Cosmetic Ingredient Handbook (17) lists 755 lu-
`
`bricious or substantive hair conditioning additives and 438 antistatic agents for
`
`creating special effects on hair.
`
`8. Depositing Conditioning Agents onto Hair
`
`For conditioning agents to deliver these special benefits to hair, they must first
`deposit on the hair or be absorbed by the hair. Conditioners may be applied to
`
`000007
`000007
`
`

`
`Conditioning
`
`69
`
`the hair and left on or they may be rinsed off. Depositing a conditioning agent
`on hair from a rinse~off formula is dependent on its affinity for the aqueous
`phase of the formulation versus its binding affinity for the hair.
`The conditioning agent‘s attraction for the formulation matrix is depen-
`dent on the charge of the conditioning agent and the number of polar versus
`nonpolar groups. A conditioning agent’s ability to bind with hair is influenced
`by the pH of the formulation,
`the conditioning agent’s chapge and molecular
`weight, and the isoelectric point of hair (18).
`'
`The isoelectric point of hair is the pH at which a protein does not migrate
`in an electric field and it relates to the acid~base properties of hair’s surface.
`Since hair is a protein, it contains both negatively charged carboxyl groups and
`positively charged amino groups at its surface. Below the isoelectric point, hair
`becomes more positive; above the isoelectric point, hair becomes more nega-
`tive, attracting materials with a positive charge. The isoelectric point of normal
`cuticle is about pH 3.7 (18).
`Cationic substances bear a positive charge at all pH's and become more
`strongly absorbed on hair as the pH increases above the isoelectric point.
`Bleached hair has a lower isoelectric point; therefore cationics tend to bind
`more strongly to bleached hair.
`The adsorption of cationic surfactants on the cuticle surface neutralizes
`negative charge and reduces the coulombic repulsion between adjacent cuticle
`scales allowing the cuticle scales to lie flat. The hair fiber then becomes smooth
`and easy to comb in the dry state (19).
`Not all conditioning agents are cationic, however. Many lubricious mate
`rials, such as silicones, oils, and esters, are nonionic; that is, they have no elec-
`trical charge. The binding of nonionics to hair is dependent on the hydropho-
`bicity or number of nonpolar groups. Binding occurs via Van der Waals forces
`and can be quite strong.
`
`C. Cationic Conditioning Agents
`
`Cationic conditioning agents are classified into two types—cationic surfactants,
`
`and cationic polymers. Cationic surfactants are compounds that contain at least
`one hydrophobic long-chain radical, usually derived from either fatty acids or
`petrochemical sources, and a positively charged nitrogen atom. Linfield (20)
`discusses the chemistry of cationic surfactants in detail. In the Surfactant En-
`
`cyclopedia (21), cationic surfactants are further subdivided into four major
`classes: alkyl amines, ethoxylated amines, quaternary salts, and alkyl imidazo-
`lines. Of these four classes, the quaternary salts are the most widely used be-
`cause of their cationic nature and the large historical database of information
`available on their performance, stability, and safety. Quaternary salts are also
`the most cost-effective on a pound-for-pound basis.
`
`000008
`000008
`
`

`
`70
`
`Hoshowski
`
`1. Cationic Surfactants
`
`a. Alkyl Amines. Organic tertiary amines are the precursors of quaternary
`salts. Organic tertiary amines are derivatives of ammonia where three hydro-
`gens have been replaced by organic radicals. These radicals may be the same
`or different, straight-chain or branched-chain, saturated or olefinic. The struc-
`ture of the resulting tertiary amine is dependent on the source of the fatty acid
`used to create the amine. A variety of natural sources such as coconut, palm,
`tallow, soybean oils, etc. yield mixtures of fatty acids as shown in Table 1.
`While the tertiary alkyl amines have been used extensively as condition-
`ing agents, more recently the amido amine structure shown in Figure 1 has
`gained favor over the tertiary amine because of its performance advantages.
`Both amines and amido amines contain a long alkyl group, but in the case of
`the amido amine, an amido group is inserted between the nitrogen and the alkyl
`group. The presence of an amido group radically influences the functional dif-
`ferences between amines and amido amines. Concentration of positive charge
`on the hydrophobic portion of the molecule imparts strong cationic properties.
`At an acidic pH,
`the amine group becomes protonated and the character
`changes from water-insoluble to water-soluble. Friedli (22) discusses the or-
`ganic chemistry of amido amines in detail.
`A variety of organic salts can be formed by complexing amido amines
`with hydroxy acids such as gluconic, glycolic,
`lactic, and salicylic acids and
`their derivatives. The complex salts that are obtained become soluble in water
`and retain their substantivy to hair. The amino benzoic acids, such as para
`amino benzoic, salicylic, and their derivatives have limited solubility in water
`and oil. Complexing them with amido amines yields cationic salts that are eas-
`ily incorporated into a formulation while being substantive to hair (23).
`
`
`
`Table 1 Typical Fatty Acid Compositions of Commonly Used Fats and Oils
`
` Fatty acid %a"SOUl'C6 Coconut Palm Tallow Soybean
`
`
`
`
`
`
`
`
`
`
`
`Caprylic
`Capric
`Lauric
`
`Myristic
`Palmitic
`Palmitoleic
`
`Cg
`C | 0
`C12
`
`C14
`C.5
`C153;
`
`5.4
`8.4
`45.4
`
`18.0
`10.5
`0.4
`
`1.0
`43.5
`
`3.5
`25.0
`
`6.5
`
`4.2
`C13
`Stearic
`33.6
`C;g;1
`Oleic
`52.6
`C1333
`Linoleic
`2.3
`C 13,;
`Linolcnic
`
`1.2 4.5Other 0.8
`
`4.5
`40.0
`I 1.0
`
`19.5
`41.0
`2.5
`
`
`
`23
`7.5
`0.9
`
`
`
`000009
`000009
`
`

`
`Conditioning
`
`71
`
`H
`1
`R€?N{CH
`
`0
`
`3
`
`CH
`I
`2 )n"|\1:
`CH3
`
`Figure 1
`
`Amino amine.
`
`\.
`
`Amido amines are generally used as secondary conditioning agents to
`
`provide a special effect such as complexation, while a primary conditioning
`agent such as a cationic surfactant is added to reduce combing force and elim-
`inate static. Formulation example #5 contains stearamidopropyl dimethylamine
`as the secondary conditioning agent.
`'
`b. Ethoxylaied Amines. Ethoxylated amines are nitrogen containing sur~
`factants whose degree of water solubility depends largely on the type and de-
`gree of alkoxylation. Ethoxylated amines are useful as hair conditioning agents
`in shampoos and clear conditioning rinses. Smith et al. (24) compared didecyI-
`methylamine oxide (DDMAO), shown in Figure 2,
`to stearyldimethylamine
`oxide (SDMAO), shown in Figure 3, and found that in a shampoo formulation
`the DDMAO was effective as a detangling agent at lower concentrations than
`SDMAO, but produced less foam. While in conditioning rinses. DDMAO was
`more effective in detangling and static control than SDMAO and stearalkonium
`
`chloride. The conditioning rinse formulas were compared at neutral pH, since
`DDMAO is not soluble at acidic pH. At acidic pH there may no longer be an
`advantage for DDMAO.
`The various tertiary amines and ethoxylated amines
`C. Quaternary Salts.
`can be alkylated with metal halide or dimethylsulfate to produce a wide vari-
`ety of possible quaternary salts. Representative structures are shown in Figures
`
`CH3
`C-IOH21 N---->0
`C1oH21
`
`Figure 2 Didecylmethylamine oxide.
`
`CH3
`C18H37 N-—~->0
`CH3
`
`Figure 3
`
`Stearyldimethylamine oxide.
`
`000010
`000010
`
`

`
`72
`
`Hoshowski
`
`+
`
`_
`
`CI
`
`CH3
`I
`Fl—N—CH3
`
`I C
`
`H3
`
`n=c8 -C2 2
`
`Figure 4 Monoalkyl quaternary salt.
`
`4-7. The number of alkyl groups, their chain length, and the absence or pres-
`ence of ethylene oxide groups determine the physical properties and perform-
`ance characteristics of quaternary salts.
`
`Quaternary salts with alkyl chains of 8 to 10 carbons exhibit germicidal
`and fungicidal properties. Recognition of this property of quaternary salts by
`Domagk in 1935 (25) led to the first important commmercial use of quater-
`nary salts.
`The shorter-chain monoalkyl quaternary salts are soluble in hydrophilic
`solvents such as water, isopropanol, and propylene glycol, while the longer-
`chain monoalkyl quaternary salts are only dispersible in water. The dialkyl qua-
`ternary salts are soluble in isopropyl alcohol and propylene glycol, and some
`may be dispersible in water. Ethoxylated quaternary salts are soluble in hy-
`drophilic solvents.
`
`When Jurczyk, et al. (26) studied the relationship between quaternary
`structure and performance characteristics on hair,
`they found that
`the chain
`length and number of fatty alkyl chains is directly proportional to improved
`conditioning perfonnance. They compared the substantivity as well as the de-
`tangling, wet combing, dry combing, and static control properties of a number
`of quaternary salts. Ethoxylated quaternary salts were found to be less substan-
`tive due to their greater solubility, with lower conditioning scores. Increasing
`the number and the length of alkyl chains resulted in increased substantivity
`with a resulting increase in conditioning properties.
`
`943
`
`[ H-ll\l-Fl ]
`
`CH3
`
`.
`
`Cl ‘
`
`Fl=C12'C22
`
`Figure 5
`
`Dialkyl quaternary salts.
`
`00001 1
`000011
`
`

`
`Conditioning
`
`73
`
`[
`
`‘EH3
`
`I'll
`
`+
`
`]
`
`F*=C16
`
`Figure 6
`
`Trialkyl quaternary salt.
`
`\
`
`Finkelstein and Laden (27) studied the kinetics of the adsorption process
`and found that quaternary salts formed micelles on the hair surface. A micelle
`is a molecular aggregate of 50 to 100 molecules that constitutes a collodial par-
`ticle, which takes the shape of spheres with their hydrophilic groups facing out-
`ward and their hydrophobic groups facing inward. Micelle formation can occur
`only with the relatively longer-chain quaternary salts and then only when a
`sufficient concentration, called the critical micelle concentration, is reached.
`
`increases the degree
`Increasing the chain length of a cationic surfactant
`of hydrophobic interactions _and thus increases the surface activity. Books
`by Rosen (28) and Rubingh and Holland (29) explain the surface chemistry of
`surfactants in.detail.
`
`Besides improving conditioning, the longer alkyl chains also contribute to
`greater mildness. The behenyl or C2; quaternary salts offer improved skin and
`eye irritation profiles over the stearyl or C13 chain length quaternary salts (30).
`There is a limit, however, to how much conditioning is desirable. Qua-
`ternary salts that are highly substantive to hair tend to deposit too heavily and
`may buildup, particularly on damaged hair. This can leave hair, especially fine
`hair, limp and difficult to style. Highly substantive conditioning agents are usu-
`ally utilized in deep conditioning treatments used weekly, rather than in daily-
`use conditioners. Formulation example #3 is such a deep conditioner.
`A twist on the quaternary salt structure is the diquaternary salt. The di-
`quaternary salt contains two positively charged nitrogen atoms. Jurcyzk et al.
`
`(Ci}H2-CI-E-0) XH
`[ Fl-l*|J—CH3
`
`(CH2-CH2-o)yH
`
`+
`
`]
`
`C,-
`
`R"'C1 2'01 8
`
`Figure 7
`
`Ethoxylated quaternary salt.
`
`000012
`000012
`
`

`
`74
`
`i:
`
`?H3
`(EH3
`l3-if-C3li2f(3ll;fC3ll2-if-(3l4;3
`
`CH3
`
`CH3
`
`Hoshowski
`
`+
`
`£2(3|—
`
`Figure 8 Di-quaternary salt.
`
`\.
`
`(31) found that the tallowdimonium propyltrimonium dichloride, whose struc-
`ture is shown in Figure 8, imparts greater conditioning benefits than its monon-
`itrogen counterpart. The presence of the two positively charged nitrogen atoms
`in one molecule can offer a favorable economy versus performance profile over
`
`the mononitrogen quaternary salts.
`A single quaternary salt may provide enough conditioning and antistatic
`benefits to be used as the sole conditioning agent in a simple, economical con-
`ditioner formulation. Formulation example #l is an economical rinse—off con-
`ditioning rinse. Usually, though, a quaternary salt is the primary conditioning
`agent, and additional secondary conditioning agents are used to further enhance
`a conditioning formu1ation’s performance.
`'
`d. Alkyl lmidazolines. Alkyl imidazolines (32) are five-membered hetero-
`cyclic rings ‘containing two nitrogens in the 1,3 positions. They are produced
`by condensation of long-chain fatty acids with ethylene diamine or its deriva-
`tives. The salts ‘of these imidazolines are widely used as cationic surfactants in
`non-personal-care applications such as textile or fabric softeners. To obtain ma-
`terials acceptable for cosmetic use, the irnidazolines are reacted with an alky-
`lating agent which usually opens the ring resulting in an amphoteric: structure
`shown in Figure 9. Amphoterics behave as anionics above the isoelectric point
`and as cationics below this pH. These mild materials are usually used to pro-
`vide conditioning in shampoos and bath products.
`
`2. Cationic Polymers
`
`The second type of cationic conditioning agent is the cationic polymer. Poly-
`mers can be natural, synthetic, or biosynthetic. A biosynthetic polymer is a nat-
`
`%’
`cl:|-5-0-OH
`p
`-
`-
`-
`-
`(E N CH2 CH2l\|J+
`0
`Cl-5-0!-I2-OH
`
`H-
`
`-
`
`Fl
`
`Figure 9 Alkyl imidazolines.
`
`000013
`000013
`
`
`
`

`
`Conditioning
`
`75
`
`ural polymer which has been modified with one or more synthetic functional
`groups. Lochhead (33) provides a detailed listing of polymers including chem-
`ical and trade names, use concentration and function in the formulation, solu-
`
`bility charactetistics, and other pertinent information.
`Three types of natural polymers are used for hair conditioning—polysac-
`charides, proteins, and nucleic acids. Numerous synthetic polymers are avail-
`able such as those derived from vinyl pytrolidone and silicones. The polymer
`backbones may impart one or more of the following attributes to hair——slip,
`
`sheen, humectancy, and body. The addition of substantive cationic sites to any
`of these types of polymers greatly increases the amount of polymer that de-
`posits on the hair.
`Polysaccharides are made up of a number of repeating
`a.
`Poiysaccharides.
`monsaccharide units, or simple sugars,
`joined together in long linear or
`branched chains. Polysaccharides have two major biological functions«—as a
`storage form of fuel, and as structural elements. The most abundant storage
`polysaccharides are starch in plants and glycogen in animals. Cellulose is the
`most abundant structural polysaccharide in plants, while chitin is a major com»
`ponent of the exoskeletons of invertebrates.
`A number of polysaccharides are used in conditioners for their thickening
`and slip properties. Attaching quaternary groups to polysaccharides results in
`molecules that combine the properties of thickening and conditioning.
`Even though both starch and cellulose are linear polymers of D-glucose,
`most mammals cannot use cellulose as food. In starch, the D-glucose units are
`bound in alpha(l -9 4) linkages, while in cellulose, the linkages are beta(l -a
`4). Most mammals, except the ruminants such as cows, do not have enzymes
`that are capable of hydrolyzing the beta(1 ~«> 4) linkages. Only a few starch de-
`rivatives are used in hair care preparations, while cellulose and its many deriv-
`atives are commonly used in hair care products.
`A number of quaternary structures have been attached to cellulose in order
`
`to create a variety of cationic celluloses. Studied extensively by Goddard (34),
`Polymer JR, or po1yquaternium—l0, is a quaternary ammonium salt of hydrox-
`yethyl cellulose and a trimethyl ammonium substituted epoxide. Adsorption of the
`cationic polymer onto hair occurs rapidly and is greater than the amount expected
`for simple monolayer adsorption, thus indicating that the polymer penetrates into
`the hair, particularly bleached hair. Goddard found that deposition is dependent
`on the type of surfactant and the ratio of polyquaternium-10 to surfactant in the
`formulation (35). In formulation example #7, an ester is used in conjunction with
`polyquaternium—10 to provide conditioning benefits without static flyaway.
`Celquat, or polyquaternium—4, is the copolymer of hydroxyethylcellulose
`and diallydimethyl ammonium chloride. Polyquatemium—4 is soluble in water,
`hydrolytically stable from pH 3 to 8, and forms glossy films on hair which im-
`part excellent curl retention even in high humidity (36).
`
`000014
`000014
`
`

`
`76
`
`Hoshowski
`
`Quatrisoft Polymer LM~200, or polyquaternium-24, is a hydroxyethylcel~
`lulose that has been reacted with a lauryl ditnethyl ammonium substituted epox-
`ide. Besides providing conditioning attributes such as good wet combing,
`reduced static, and a soft silky feel, polyquaternium-24 increases stability of
`oil-in-water emulsions and increases the foam stability of aerosol mousses (37).
`Another group of quatemized cellulose polymers, the Crodocels, combine
`the cellulose polymer with a fatty quaternary salt. A unique combination of lu-
`bricity and a silky feel on the hair is a direct result of covalently binding a fatty
`quaternary group to the cellulose backbone (38).
`Guar hydroxy propylttimonium chloride is an excellent thickener which
`disperses easily in water, is pH-stable over a wide range, and is compatible with
`surfactants and salts. Guar gums are available in a variety of viscosities and de-
`grees of quatetnization, offering the cosmetic chemist formulation flexibility (39).
`Derived from crustacean shells, chitin and its more soluble deacetylated
`derivative, chitosan, are natural cationic materials that have found a number of
`intriguing applications, including use as wound healing agents, beverage clari-
`fying agents, and flocculants in wastewater treatment. Combining chitosan with
`pyrrolidone carboxylic acid (PCA) forms a water-soluble substantive humectant
`whose CTFA name is chitosan PCA. Chitosan PCA is nonirritating and forms
`polymeric films on the hair (40).
`Chitosan that has been reacted with propylene glycol and quatemized with
`epichlorohydrin has the CTFA name of polyquatemium*29. Compatible with all
`types of surfactants and stable over the pH range from 2 through 12, polyquater—
`nium-29 exhibits excellent hair fixative properties at low active levels (41).
`b.
`Proteins.
`Proteins serve many diverse biological functions acting as cat-
`alysts in enzymes, structural elements in bone collagen and hair keratin, nutri-
`ent storehouses in milk casein and egg ovalbumin, and many more. Proteins are
`made up of one or more polypeptide chains which in turn are made up of many
`alpha-amino acid residues linked together by a peptide bond. There are 20 dif-
`ferent alpha—amino acids commonly found in proteins (42), listed in Table 2. All
`of these amino acids, except for proline, contain a free carboxyl group and a
`free unsubstituted amino group on the alpha-carbon. The amino acids differ
`from one another by their side chain R groups. Many amino acid residues are
`
`Table 2 Alpha Amino Acids
`
`Alanine
`
`Arginine
`
`Asparagine
`
`Aspartic Acid
`
`Cysteine
`
`Glutamine
`
`Glutamic acid
`
`Glycine
`
`Histidine
`
`Isoleucine
`
`Leucine
`
`Lysine
`
`Methionine
`
`Phenylalanine
`
`Proline
`
`Serine
`
`Threonine
`
`Tryptophane
`
`Tyrosine
`
`Valine
`
`
`
`000015
`000015
`
`

`
`Conditioning
`
`77
`
`arranged in complex specific sequences to form proteins which range in mole-
`cular weight from about 5000 to over 1 million.
`Since protein molecules are too large to penetrate normal hair, proteins
`are partially hydrolyzed to a peptide mix or completely hydrolyzed and used as
`the individual amino acids. Johnsen (43) found that protein fractions with a
`molecular weight of 1000 or less were the most substantive to hair.
`Since proteins contain both positively and negatively\ charged R groups,
`they exhibit amphoteric behavior. Commercially available proteins have iso-
`electric points in the pH range of 4.0 to 6.0, limiting the practical range for true
`cationic behavior. Also, the amount of positive charge on the protein is small.
`By covalently grafting a quaternary ammonium group onto a protein, the
`cationic properties are greatly enhanced. Protein fractions of higher molecular
`weights become substantive to hair. Quatemization increases the isoelectric
`point considerably; thus, quatemized proteins retain cationic properties over a
`wider pH range increasing their versatility in formulations. Jones (44) used ra-
`dioactive labeling techniques to compare deposition on hair of a quatemized
`protein versus its parent protein and found that twice as much of the quater-
`nized protein deposits on hair.
`Attaching a fatty alkyl group to the quaternary nitrogen of a protein hy-
`drolysate that has a molecular weight of 1000 to 2000 results in materials with
`a unique combination of properties. These protein derivatives are stongly
`cationic, yet compatible with amphoterics and anionics, soluble at acid pH, mild
`to skin and eyes, and exhibit biocidal and foaming properties. Steartrimonium
`hydrolyzed animal protein is the stearyl trimethylammonium salt of a collagen
`hydrolysate, which gives a substantive conditioning agent, that provides body
`and gloss to hair. Stern and Johnsen (45) found that cocotrimonium collagen
`hydrolysate performed similarly to stearalkonium chloride in combing proper-
`ties, but was preferred over stearalkonium chloride for the hair’s bodying ef-
`fects as measured by curl bounce and fullness.
`Recently, proteins derived from vegetable sources have been introduced.
`
`in particular wheat and soy that have been extensively
`Plar1t~derived proteins,
`hydrolyzed to low-moleculanweight polypeptides or amino acids, are claimed
`to be comparable to the animal-derived protein hydrolysates. However, where
`a more complex, three—dimensional protein structure is involved, as in the case
`of collagen, it
`is not possible to offer plant-derived prote