Hair fixative amphoteric polymer composition

An amphoteric, hair fixative polymer for use in hair sprays, gels, and the like contains 40-90 percent of a hydroxyl-containing ethylenically unsaturated monomer, 1-20 percent of an acid-containing ethylenically unsaturated monomer, and 1-20 percent of an amine-containing ethylenically unsaturated monomer. The polymer has hydroxyl, acid and amine functionalities and, while being insoluble in water, can be solubilized in water by the use of amine neutralizers, acidic neutralizers, or by solubilizing in alcohol-water mixtures. The polymers provide hair fixatives that are fast drying, and have excellent curl retention with low curl droop.

FIELD OF THE INVENTION 
The present invention relates to hair fixative polymer compositions that 
can be used in hair fixative formulations and which provide fast drying, 
excellent curl retention with low curl droop, and a soft, silky feel to 
the touch. 
BACKGROUND OF THE INVENTION 
Hair fixative formulations, containing hair fixative polymers, have been 
extensively used in aerosol sprays, pump sprays, mousses and gels. 
Typically these hair fixative formulations make use of large amounts of 
alcohol, most often ethanol, in amounts of 80% or more by weight, as the 
principle solvent. These alcohol solvents are designated as volatile 
compounds and contribute in large part to the volatile content, (VOC), of 
these formulations. Efforts to reduce the VOC, and thereby reduce the 
alcohol content, of hair fixative formulations has usually involved the 
replacement of some or all of the alcohol with water. Hair fixative 
polymers which are dissolved in alcohol-water mixtures, or water alone, 
typically require the addition of a volatile amine neutralizing agent. The 
amine neutralizing agent forms a salt with pendant acid groups on the 
polymer, allowing the polymer to be solubilized into the water or 
alcohol-water mixture. Upon application, the amine, and alcohol if 
present, is volatilized and the hair fixative polymer becomes less soluble 
in the remaining water droplets and sticks to the hair shafts. 
Unfortunately, the majority of volatile amine neutralizing agents are also 
considered to be toxic, to some degree. Thus it would be desirable to 
develop hair fixative polymers which can be solubilized in water or in 
water-alcohol mixtures without reliance on the use of amine neutralizers. 
In addition to providing hair fixatives having reduced VOC contents, it is 
important that the polymers used provide properties which enhance the hair 
fixative formulations. For example, the polymer should have fast drying 
properties such that upon application to the hair, excessive drying time 
is not required. Also, while fast drying is important, it is also 
important that the hair fixative polymer also provide for low curl droop 
upon application and high curl retention under high humidity conditions. 
The polymer compositions used in hair fixative formulations should thus 
provide a number of beneficial physical properties on use while the same 
should be solubilized in a manner which would enable reduction of VOC 
content in hair fixative formulations using such polymers. Furthermore, it 
should provide manageability of the hair upon application and drying, and 
it should be easily removable upon shampooing. 
SUMMARY OF THE INVENTION 
A hair fixative polymer composition is provided which comprises an 
amphoteric polymer that is water insoluble but which can be solubilized in 
water by either adding an acid neutralizing agent, or adding an amine 
neutralizing agent, or adding a low-boiling, water miscible alcohol to 
water to solubilize or disperse the polymer therein. 
The hair fixative polymer is an amphoteric polymer that contains, by 
weight, ethylenically unsaturated monomers that comprise 40-90 percent of 
a hydroxyl-containing ethylenically unsaturated monomer which provides 
hydroxyl functionality to the polymer; 1-20 percent of an acid-containing 
ethylenically unsaturated monomer which provides carboxy functionality to 
the polymer; and 1-20 percent of an amine-containing ethylenically 
unsaturated monomer which provides amine functionality to the polymer. The 
amphoteric polymer may also contain up to 40 percent of ethylenically 
unsaturated monomers that are devoid of acid, amine, and hydroxyl 
functionalities. For any particular amphoteric polymer, the total of the 
weight percentages of the monomers equals 100. 
A preferred amphoteric polymer of the present invention contains by weight, 
40-90 percent of 2-hydroxyethyl methacrylate, 1-20 percent by weight of 
acrylic acid or methacrylic acid, 1-20 percent of N,N-dimethylaminoethyl 
methacrylate, and 10-30 percent of styrene or methyl methacrylate. 
The hair fixative amphoteric polymers of the present invention may be used 
in hair fixative compositions such as sprays, gels, and the like for hair 
fixing purposes. 
DETAILED DESCRIPTION 
The present invention provides an amphoteric polymer, usable as a hair 
fixative polymer composition, that is water insoluble but which can be 
either 1) solubilized or dispersed in water as a salt of a water soluble 
acid (cationic form), 2) solubilized or dispersed in water as a salt of a 
water soluble amine (anionic form) , or 3) solubilized or dispersed in an 
alcohol-water mixture (nonionic form). The polymer contains hydroxy, acid 
and amine functionalities in a proportion sufficient to render the same 
insoluble in water but solubilizable by volatile acids or amines. 
The hair fixative polymer composition contains 40-90 percent by weight, and 
preferably 50 to 75 percent, of a hydroxyl-containing ethylenically 
unsaturated monomer which provides hydroxyl functionality to the resultant 
polymer. Typically useful hydroxyl-containing ethylenically unsaturated 
monomers are hydroxy alkyl acrylates and hydroxy alkyl methacrylates such 
as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl 
acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate and 
hydroxybutyl methacrylate, and the like. 
The hair fixative polymer composition also contains 1-20 percent by weight, 
and preferably 2 to 15 percent, of an acid-containing ethylenically 
unsaturated monomer. The term "acid-containing ethylenically unsaturated 
monomer" as used herein describes a monomer that will provide pendant acid 
groups in polymer and thus provides acid functionality to the resultant 
polymer. Particularly useful acid-containing ethylenically unsaturated 
monomers include acrylic acid and methacrylic acid, while other such 
acid-containing ethylenically unsaturated monomers usable include, 
10-undecenoic acid, crotonic acid, beta-carboxyethyl acrylate, and the 
like. 
A third component of the hair fixative polymer composition is an 
amine-containing ethylenically unsaturated monomer, which provides pendant 
amine groups to the polymer, and is present in an amount of 1-20 percent 
by weight, and preferably about 5 to 15 percent. Such amine-containing 
monomers include amine functional acrylates and methacrylates, such as 
N,N-dimethylaminoethyl methacrylate, tert-butylaminoethyl methacrylate, 
N,N-diethylaminoethyl methacrylate, and the like. 
Optionally, about 0-40 percent by weight, and preferably about 10 to 20 
percent, of an ethylenically unsaturated monomer that is devoid of acid, 
amine and hydroxyl functionalities may be added to the polymer 
composition. Such a monomer may be an alkyl ester of acrylic or 
methacrylic acid, such as methyl methacrylate, ethyl methacrylate, butyl 
methacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, vinyl 
aromatic monomers such as styrene and vinyl toluenei nitrile monomers such 
as acrylonitrile and methacrylonitrile; vinyl esters such as vinyl 
acetate; and vinyl amides such as acrylamide and N-alkylacrylamides and 
cyclic amides. 
An especially useful amphoteric polymer is one containing about 40-90 
percent by weight of 2-hydroxyethyl methacrylate: 1-20 percent by weight 
of acrylic acid: 1-20 percent by weight of N,N-dimethylaminoethyl 
methacrylate; and about 10-30 percent by weight of styrene or methyl 
methacrylate. 
The polymers of the present invention may be prepared by conventional 
solution polymerization techniques which are well known in the art. This 
polymerization is usually carried out in an organic solvent under reflux 
conditions with an appropriate initiator having a specific half-life of 
decomposition. The polymer conversion is usually better than 95 percent. 
The free monomers after polymerization can be reduced by further addition 
of initiator and longer hold time or both, as necessary. It can be further 
reduced if necessary by redox initiators in the aqueous medium after 
inversion from non-aqueous medium in cases where such inversion is 
possible and acceptable. 
Alternately, the polymer may be prepared by aqueous emulsion or dispersion 
polymerization, where the polymerization is carried out in the medium of 
water, in the presence of surface active agents, by water soluble 
initiators which are primarily inorganic peroxydisulfates. 
The amphoteric polymer of the present invention should have a molecular 
weight (number average molecular weight) of between about 1500 to 
1,000,000, preferably between about 2500 to 100,000, and most preferably 
between about 5000 to 25,000, and a calculated glass transition 
temperature (Tg) of between 40-80.degree. C. 
The amphoteric polymers of the present invention are insoluble in water 
but, due to the acid functionality and the amine functionality present, 
the amphoteric polymer can be solubilized or dispersed in water either 
anionically as a salt of a water soluble amine, or cationically as a salt 
of a water soluble acid, or nonionically by dissolution in an 
alcohol-water mixture where the ratio of the alcohol and water depends 
upon the particular polymer composition. The amines or acids used to 
solubilize the polymer are preferably volatile compounds such that upon 
their release during drying the polymer becomes insoluble in water. 
Amines that are usable as neutralizing agents include 
2-dimethylaminoethanol N,N-dimethylethanolamine), 
2-amino-2-methyl-1-propanol, 3-dimethylamino-1-propanol, 
3-dimethylamino-2-propanol, 1-amino-2-propanol, ethanolamine, ammonia, and 
the like. 
Acids that are usable as neutralizing agents include carbonic, formic, 
acetic, lactic, trifluoro acetic acid, and the like, with carbonic and 
acetic acids being preferred. 
The amount of amine or acid added to the amphoteric polymer is that 
sufficient to solubilize the polymer in water or a predetermined 
alcohol-water mixture. Between about 1-100 percent of the carboxyl or 
amine pendant groups should be neutralized, with about 20 to 50 percent of 
total neutralization preferred. 
Or, the amphoteric polymer may be dissolved in a mixture of a low-boiling, 
water miscible alcohol and water, the alcohols being selected from a 
monohydric alcohol having 2 or 3 carbon atoms, such as ethanol or 
propanol. The amount of alcohol added to dissolve the amphoteric polymer, 
in nonionic polymer mode, will depend on the particular polymer and is an 
amount sufficient to disperse or solubilize the polymer. The percent of 
water in the total solution will be between 0 to 85 percent, preferably 
between about 30 to 80 percent, and most preferably between about 70 to 80 
percent. 
In the formation of hair fixative formulations incorporating the present 
hair fixative polymers, propellants, known in the art, would be added to 
polymer solutions for use in hair sprays. An especially useful propellant 
would be carbon dioxide which can also be present as a neutralizing agent 
for cationic solubilization of the hair fixative polymer. The propellant 
is added in an amount sufficient to enable application of a solution of 
the hair fixative polymer, in a desired amount, to hair, as is known in 
the art. 
The following examples further illustrate the present invention in its 
preferred embodiments. 
As used in the body of the present specification, examples, and claims, all 
percents, ratios and parts are by weight unless otherwise specifically 
indicated. 
In the following examples, the Tg's, (glass transition temperatures), were 
determined through use of the Fox equation, the % weight solids were 
determined at a temperature of 110.degree. C. for one hour and the number 
average molecular weights were determined from gel permeation 
chromatography using polystyrene as the standard and N,N-dimethylformamide 
as the solvent.

The following examples, 1 through 5, describe the preparation of polymers 
which are particularly useful in the practice of the invention. 
EXAMPLE 1 
This example illustrates the preparation of an amphoteric acrylic polymer 
utilized in a hair fixative composition according to the present 
invention. 
The following were charged to a suitable reaction vessel equipped with an 
agitator, a reflux column, a thermocouple and a heating mantle: 
______________________________________ 
Material Weight (grams) 
______________________________________ 
Charge-1 
Ethanol 935.0 
Charge-2 
VAZO-67.sup.(1) 38.2 
Acrylic acid 18.0 
2-Hydroxyethyl methacrylate 
513.3 
N,N-Dimethylaminoethyl methacrylate 
79.2 
Methyl methacrylate 152.6 
Ethanol 300.0 
______________________________________ 
.sup.(1) Vazo67 chemically is 2,2Azobis-(2-methylbutyronitrile) and is 
available commercially from E. I. duPont de Nemours and Company. 
(1) Vazo-67 chemically is 2,2'-Azobis-(2-methylbutyronitrile) and is 
available commercially from E. I. duPont de Nemours and Company. 
Charge-1 was initially added to the reaction vessel and heat was applied 
with agitation until a temperature of reflux was reached. Charge-2 was 
then fed into the reaction vessel in a continuous manner over a period of 
three hours. The reflux temperature was maintained throughout the addition 
of the Charge 2. With the completion of the addition of Charge 2, the 
reaction mixture was held for an additional three hours at the reflux 
temperature. The contents of the reaction vessel were then cooled and 
transferred to a suitable container. The resultant polymer solution had a 
total solids content, based on total solution weight, of 42.5%, a number 
average molecular weight of 9306, and a Tg (glass transition temperature) 
of 60.5.degree. C. 
EXAMPLE 2 
This example illustrates the preparation, in accordance with the method 
described in Example 1, of an amphoteric styrene-containing acrylic 
polymer utilized in a hair fixative composition according to the present 
invention. 
The following were charged to a suitable reaction vessel equipped with an 
agitator, a reflux column, a thermocouple and a heating mantle: 
______________________________________ 
Material Weight (grams) 
______________________________________ 
Charge-1 
Ethanol 467.5 
Charge-2 
Vazo-67 19.1 
Acrylic acid 9.0 
2-Hydroxyethyl methacrylate 
256.7 
N,N-Dimethylaminoethyl methacrylate 
39.6 
Styrene 76.3 
Ethanol 150.0 
______________________________________ 
The resultant polymer solution had a total solids content, based on total 
solution weight, of 40.5%, a number average molecular weight of 9596, and 
a Tg of 59.70.degree. C. 
EXAMPLE 3 
This example illustrates the preparation, in accordance with the method 
described in Example 1, of an amphoteric acrylic polymer with a lower Tg 
than those of Examples 1 and 2, which can be utilized in a hair fixative 
composition according to the present invention. 
The following were charged to a suitable reaction vessel equipped with an 
agitator, a reflux column, a thermocouple and a heating mantle: 
______________________________________ 
Material Weight (grams) 
______________________________________ 
Charge-1 
Ethanol 467.5 
Charge-2 
Vazo-67 19.1 
Acrylic acid 9.0 
2-Hydroxyethyl methacrylate 
294.8 
N,N-Dimethylaminoethyl methacrylate 
39.6 
Methyl methacrylate 38.2 
Ethanol 150.0 
______________________________________ 
The resultant polymer solution had a total solids content, based on total 
solution weight, of 40.6%, a number average molecular weight of 10,560, 
and a Tg of 56.0.degree. C. 
EXAMPLE 4 
This example illustrates the preparation of a cationic amphoteric acrylic 
polymer, in an isopropanol and water solvent mixture, with the isopropanol 
distilled off after neutralization with acetic acid, which can be utilized 
in a hair fixative composition according to the present invention. 
The following were charged to a suitable reaction vessel equipped with an 
agitator, a reflux column, a thermocouple and a heating mantle: 
______________________________________ 
Material Weight (grams) 
______________________________________ 
Charge-1 
Isopropanol 300.0 
Deionized water 167.5 
Charge-2 
Vazo-67 19.0 
Acrylic acid 9.0 
2-Hydroxyethyl methacrylate 
331.2 
N,N-Dimethylaminoethyl methacrylate 
39.6 
Isopropanol 150.0 
Charge-3 
Glacial acetic acid 3.8 
Charge-4 
Deionized water 1000.0 
______________________________________ 
Charge-1 was initially added to the reaction vessel and heat was applied 
with agitation until a temperature of reflux was reached. Charge-2 was 
then fed into the reaction vessel in a continuous manner over a period of 
three hours. The reflux temperature was maintained throughout the addition 
of Charge 2. With the completion of the addition of Charge 2, the reaction 
mixture was held for an additional three hours at the reflux temperature. 
At this point, the resultant polymer solution was found to have a total 
solids content, based on total solution weight, of 40.6% and a number 
average molecular weight of 13,728. The contents of the reaction vessel 
were then cooled to a temperature of 76.degree. C., after which Charge-3 
was added. Charge-4 was then added and the contents of the reaction vessel 
were heated to a temperature at which an azeotropic distillation of the 
isopropanol was performed. After the completion of the azeotropic 
distillation of the isopropanol, the contents of the reaction vessel were 
cooled and transferred to a suitable container. The resulting aqueous 
dispersion was found to have a total solids content, based on total 
solution weight, of 32.0%, a pH of 6.60 and a Tg of 51.70.degree. C. 
EXAMPLE 5 
This example illustrates the preparation, in accordance with the method 
described in Example 4, of an anionic amphoteric acrylic polymer, in an 
isopropanol and water solvent mixture with the isopropanol distilled off 
after neutralization with N,N-dimethylethanol amine, which can be utilized 
in a hair fixative composition according to the present invention. 
The following were charged to a suitable reaction vessel equipped with an 
agitator, a reflux column, a thermocouple and a heating mantle: 
______________________________________ 
Material Weight (grams) 
______________________________________ 
Charge-1 
Isopropanol 300.0 
Deionized water 167.5 
Charge-2 
Vazo-67 19.0 
Acrylic acid 9.0 
2-Hydroxyethyl methacrylate 
331.2 
N,N-Dimethylaminoethyl methacrylate 
39.6 
Isopropanol 150.0 
Charge-3 
N,N-Dimethylethanol amine 
11.1 
Charge-4 
Deionized water 1000.0 
______________________________________ 
The resulting anionic aqueous dispersion was found to have a total solids 
content, based on total solution weight, of 29.3%, a pH of 8.84 and a Tg 
of 51.7.degree. C. 
EXAMPLE 6 
Hair fixative polymer compositions of the present invention were tested to 
evaluate various hair fixative properties, such as Curl Retention, Initial 
Droop and Drying Time according to the following procedures. 
Curl Retention 
Curl retention evaluation of the hair fixative polymer compositions of the 
present invention was made using 5 tresses (virgin European brown hair, 8" 
long, 2 gm) for each polymer. Each tress was prepared by first washing 
with a 1% sodium lauryl sulfate solution at 45.degree. C. for 60 seconds. 
The tresses were then rinsed in running tap water at 40-45.degree. C. for 
60 seconds, the rinsed tresses drained for three minutes and combed out to 
remove excess water and twists. Using a syringe, 1.2 mls of polymer 
solution (1.5% polymer in ethanol) were applied to each tress and the 
polymer solution combed through the tress. Each tress was then wrapped 
onto a 5/8" diameter mandril and dried in an oven at 60.degree. C. for 90 
minutes. The tress was then removed from the mandril and mounted in a 
glovebox at 70-75.degree. F. at 85-90% relative humidity. The initial curl 
length was then recorded. The curl length was further recorded at regular 
time intervals through a 2-hour period. The curl retention (% CR) was 
calculated at each time interval for each tress as follows: 
##EQU1## 
The average % Curl Retention for the 5 tresses at each time interval was 
taken to get a single value. This described method is designated as Method 
1. 
A second method, Method 2, was also used for some Curl Retention evaluation 
which was the same procedure as Method 1, except for the following 
alterations: 
a) the 1.2 ml polymer solution was a solution of 1.5% polymer in a 55% 
ethanol--43.5% water mixture; 
b) after wrapping on the 5/8" diameter mandril, the tress was dried 
overnight at 70-75.degree. F. and 50-60% relative humidity; and 
c) the curl length was recorded at regular time intervals through a 6-hour 
period. 
Initial Droop 
Initial droop evaluation of the hair fixative polymer compositions of the 
present invention was made using 5 tresses, with comparable tresses used, 
and shampooing and rinsing the same as described with the Curl Retention 
method. After the rinsing, the wet tress was then wound around a 5/8" 
diameter mandril and dried in an oven at 50.degree. C. for 20-23 hours. 
The tress was slid off the mandril and mounted at ambient conditions. The 
initial curl length was measured. Using an Emson Z-VOC pump. Series 040, 
at a distance of 7", 6 pumps of polymer solution (1.56 polymer, 55% 
ethanol and 43.5% water) were applied onto the tress, and a timer started. 
The curl length was then measured after 1, 2 and 3 minutes. The % Droop 
was calculated as follows: 
##EQU2## 
The average of the % Droop values for the 5 tresses was used to calculate 
the Average % Droop at 1, 2 and 3 minutes. 
Drying Time 
Method A (Tactile Endpoint) 
A Sag and Levelling Test Chart (The Laneto Co., Ho-Ho-Kus, N.J.), was 
vertically mounted with the back of the board facing forward. Using an 
Emson Z-VOC pump, series 040, a solution of polymer (1.5% polymer in 55% 
ethanol and 43.5% water) was pumped once from a distance of 8" onto the 
back of the board and a timer started. The board was observed through an 
oblique angle: a bright reflection could be seen off wet areas. The areas 
assume a matte appearance as they dry. Once the wet area took on a matte 
appearance, the area was tapped lightly with a finger, feeling for 
residual tackiness left by the polymer. Tapping was continued until no 
tackiness was evident and the area felt the same as a non-sprayed area. 
This time was recorded as the drying time. 
Method B (Visual Endpoint) 
A standard 8.5.times.11" sheet of photocopy paper was vertically mounted. 
Using an Emson Z-VOC pump, series 040, a solution of polymer (1.5% 
solution of polymer in 556 ethanol and 43.5% water) was pumped twice from 
a distance of 7" onto the sheet and a timer started. The sheet was placed 
on a Logan Desktop Lightbox on which two sheets of polarizing film were 
set at right angles to each other, making a deep blue light. The wet areas 
of the paper were clearly visible since they transmitted this light to a 
much greater extent than did the dry areas. As the paper dried, it became 
more opaque. The drying time was noted when there were no longer any areas 
transmitting the cross-polarized light. 
The Curl Retention, Initial Droop and Drying Time of various of the polymer 
compositions produced in Examples 1-5 were evaluated according to the 
aforementioned procedures and are listed in Table I. 
TABLE I 
______________________________________ 
(Curl Retention) 
Curl Retention (%) 
Polymer Method 1 Method 2 
______________________________________ 
Gantrez .RTM. ES-225.sup.(1) (Control) 
88.0 -- 
Polymer of Example 4 
98.6 -- 
Polymer of Example 5 
95.9 -- 
Water (control) -- 52.2 
Amphomer.sup.(2) (control) 
-- 90.0 
Polymer of Example 1 
-- 96.5 
Polymer of Example 2 
-- 97.9 
Polymer of Example 3 
-- 97.9 
______________________________________ 
.sup.(1) an ethyl halfester of a linear copolymer of methylvinylether and 
maleic anhydride having a molecular weight of about 70,000 available from 
ISP Corporation. 
.sup.(2) an octylacrylamide/acrylates/butylaminoethyl methacrylate polyme 
(See U.S. Pat. No. 4,192,861) available from National Starch and Chemical 
Corporation. 
(Initial Droop and Drying Time) 
______________________________________ 
Initial Droop (%) 
Drying Time (Seconds) 
Polymer 1 min 2 min 3 min Method A 
Method B 
______________________________________ 
Gantrez .RTM. ES-225 
7.5 8.8 10.4 86 243 
(control) 
Polymer prepared in 
3.9 5.4 7.0 20 68 
accordance with 
Example 4 
______________________________________ 
The amphoteric polymers in a cationic state of the present invention have 
the additional advantage in that additions of an acid to neutralize the 
same provides a non-toxic neutralizer which is faster evaporating and 
enhances faster drying, which is an important factor in hair fixatives. 
Furthermore, the acid neutralization provides a better adhesion to the 
hair by the acid-amine coordination. This is believed to be because hair 
is amphoteric and has an isoelectric point at a pH of about four. As a 
result, at a pH higher than about four, it is in a anionic state and thus 
adheres well to the cationic polymer, where adhesion by coordination also 
promotes faster drying. Also, the acid functionalities of the amphoteric 
polymer not only provide ionic cross-linking insolubilization and faster 
drying, but such are needed for ease of removal upon shampooing. A polymer 
without such acid functionality would be difficult to remove.