Note: Descriptions are shown in the official language in which they were submitted.
MAJEWICZ~MESHRE~I 1
~ 3 ,~ AQA
OI~ SOLUBLE POLYSACCHARID~S
Field of ~h~ Iav~
This invention relates to polymers which are soluble in
and thick~n organic solvents such as mineral oil and fatty
esters. In particular the invention relates to palmitate and
stearate esters of polysaccharides.
~ackg~oun~Lof th~ In~n~iQn:
Esterification of polysaccharides was known prior to
the present invention U.5. Patents 2,055,892 and 2,055,893
which disclose a process for manufacturing hydro~yalkyl
derivatives of cellulose and other carbohydrate materials.
U.S. Patent 2,816,887 discloses the acid catalyzed, fatty
acid acylation of cellulose and cellulose ethers to produce
hydro~yethyl cellulose acetate and hydro~yethyl cellulose
propionate. U.S. 3,435,027 discloses a process of preparing
water soluble ether esters of cellulose by acylating a water
soluble cellulose ether. It also discloses a water-based
mi~ture of hydro~yethylcellulose and stearic acid. German
Offenle~ungsshri t DE 31 26 593 Al "Lubricants and New
Cellulose Ether Esters~ diicloses stearic and palmitic acid
esters of hydro~yethylcellulose and methylcellulose as
lubricant viscosifiers. U.S. Patent 4,963,492 discloses a
transesteriication process. U.S. 3,629,277 discloses
phthalic acid esters of hydroxypropylcellulose and other
cellulose ether~. U.S. Patent 3,824,085 discloses the
acetate and laurate esters of hydro~ypropylcellulose and
hydroxypropyl star~h. U.S. Patent 3,870,701 discloses the
acetate ester of benzyl hydro~ypropylcellulose and its use as
a gelling agent for organic solvents. U.S. Patent 3,940,389
discloses the acetat~ ester of methyl hydro~ypropylcellulose
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and its use as a gelling agent for orqaniC solvents~ U. S.
Patent 4,226,981 discloses a mi~ed ester useful as an enteric
coating for drugs prepared by esterification of a cellulose
ether with a mi~ture of succinic anhydride and an anhydride
of an aliphatic monocarboxylic acid.
Yet in spite of what was known, it remained for the
present discovery to provide oil soluble polysaccharides
useful as thickeners for cosmetic and toiletry applications.
Sum~rr o~ t~ In~e~tiQ~:
It is an object of the invention to provide palmitate
and stearat~ esters of polysaccharides in particular
cellulose ethers.
.
Stearate and palmitate esters of hydro~ypropylcellulose
are preferred where the hydro~ypropylcellulose has a
molecular weight above 50,000 and tha exten~ of ester
substitution is sufficient to impart solubility in mineral
oil and~or fatty acids.
It is a further object of the invention to provide a
method for producing p~lysaccharide palmitats and stearate
esters comprising the steps:
(l) mising a polysaccharide in an organic solvent;
(2) est~rifying the polysaccharide with a palmitate
and/or stearate moiety in the pre~ence of a
catalyst; and
(3) recovering a palmitate polysaccharide ester, a
stearate polysaccha~ide ester or a mi2ed palmitate
and stearate polysaccharide ester.
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Ln a preferred method the catalyst is triethylamine~
the polysaccharide is hydro~ypropylcellulose and the organic
solvent is methylene chloride.
Detq~ rie~iQ~ of th~ ~ve~iQ~:
various grades of mineral oil, as well as aliphatic
esters such as isopropyl myristate and isopropyl palmitate,
and aromatic esters such as alkyl benzoate esters, are widely
used in the cosmetic industry. Silicone fluids, jojoba oil
and essential oils are also used. Compositions o~ matter
which would be suitabla to dissolve in and thicken these oils
and esters have been sought after to aid in cosmetic
formulations. The discovery provided by the present
invention makes possible such an advance in the state of th~
art .
Polysaccharide~ suitable for the practice of the
invention are currently available in commercial or
developmental quantitie~ from a variety of sources. These
polysaccharides can b~ grouped into the categories of (l)
cellulose ethers, (2) polygalactomannans and (3~ starches.
Within group ~1) hydro~ypropylcellulose is a preferred
cellulose ether, whil~ other suitable cellulose eth~rs
include methylcellulose, carboxymethylhydro~ypropylcellulose,
hydro~ypropylm~thylcollulose and
hydroxypropylhydro~yethylcellulose. Thes~ materials are
available from Rqualon Company (a Hercules Incorporated
company), Dow Chemical Company and Shin-Etsu Chemical.
Within qroup (2) hydro~ypropylguar i5 a preferred
polygalactomman whil~ guar and carbo~ymethylhydro~ypropylguar
are also suitable within group (~) hydro2ypropyl starch is a
preferred material.
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The preferred polysaccharide is hydroxypropylcellulose
of M.S. 3.0-4.5 (available from Aqualon Company under the
tradename Klucel 3) .
It was discovered that a polysaccharide substituted
with hydro~ypropyl groups gave particularly useful benefits
for cosmetic and toiletry applications. In this respect a
palmitate ester of hydro~ypropylcellulose having a molar
substitution by hydro~ypropyl betweerl 3.0 and 4.5 and a
molecular weight above 50,000 was discovered to be the most
beneficial for cosmetic and toiletry applications.
Esterification of the polysaccharide in an organic
solvent or mi~ture o solvents is accomplished usin~ a moiety
such as stearic acid chlorid~ or palmatic acid chloride or an
anhydride thereof which can react to orm the palmitate
and/or stoarate ester. It is essential for a cellulose
ether, polygalactomannan or starch to contain reactive
hydro~yl groups in order for esterification to take placa.
This hydro~yl reactivity i9 not inhibited if the
polysaccharide is partially modified with oth2r groups.
Thus, the preferred hydro~ypropylcellulose could contain
other modifying group~ ~uch as methyl, ethyl, carbo~ymethyl,
etc. or even long chain hydrophobic alkyl or arylalkyl groups
such as butyl, cetyl or nonylph2nyl.
It ha~ been the e~perience of persons of ordinary s~ill
in the art that degr~ of substitution values determined by
sa~onification technigu~s lack accuracy and precision for
cellulo~ic derivatives. As a result it ha~ been discovered
that measurements of the ratio of the carboxyl ester to
hydro~yl stretching bands in ths Infra Red (IR) at
30 appro~imately 1734 cm~l and 3470 cm~l is useful in assessing
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ae degree of esterification. A ratio great:er than 0.5
roughly corr~sponds to degrees of substitution which promote
oil solubility. A preferred range for this ratio is from
about 0.5 to about 50Ø
Esterification equipment and techniques useful for the
practice of the invention are known irom general practice in
the art and as described in the refer.ences contained in the
Background of the Invention. Triethylamine is a preferred
catalyst for esterification of the polysaccharide. It is
also preferred that tetrabutylammonium hydrogen sulfate be
used as a catalyst for a phase transfer esterification,
whereas sodium methoside/sodium borohydride is a preferred
catalyst for trans-esterification.
In d~tail the process of the invention involves:
Mi~in~: A solution or slurry su~pen~ion of the
polysaccharide is prepared in at least one organic
solvent. The solution or slurry suspen~ion typically
will contain from 0.05 to 0.15 mole of polysaccharide
in from 0.5 to 1.5 mole of organic solvent. Good
result have been obtained usinq methylene chloride,
pyridine, toluen~ and 1,4-dio~ane and combinations
thereof~ An aqueous phase will also be required when a
phase transfer reaction is run.
Est&Liicatio~: Once the polysaccharide has been
susp~nded in either solution or slurry suspension,
est~rification can occur. In the event it is desired
to pr~pare a mi~ed ester, the esterification can be
done in one step with a mixture of, for instance,
stearic acid chloride and palmitic acid chloride or
stepwise by first reactin~ with stearic acid chloride
followed by palmitic acid chloride. Suitable catalysts
include triethylamine, sodium metho~ide/sodium
borohydride, tetrabutylammonium hydrogen sulfate,
concentrsted sulfuric acid, p toluenesulfonic acid or a
cation e~change resin in hydrogen or acid orm,
depending on the type of esteriEication reaction being
undertaken.
RecQvery: When the esterification reaction has been
completed, ~i~ed or single esters can be recovered by
conventional steps of neutraliz:ation and washing.
After cooling the reaction mi~t:ure; organic solvents
such as acetone, toluene or methanol containing a small
amount of water are added to destroy the e~cess acid
chloride and precipitate the ester. Further washing
can follow.
~ : Purified e~ters made according
to the inv~ntion can be formulated into cosmetics due
to their property of being soluble in both mineral oil
and light esters such as jojoba oils, isopropyl
myristate or isopropyl palmitate and aromatic esters
such as benzoic acid alkyl esters.
An oil base cleansing or protective formulation
suita~le for incorporating a polysaccharide palmitate
comprises:
In~edi~n~ Wt
Isopropyl pslmitate 14.9
Lanolin oil 23.9
Light mineral oil 97.2
Dow Corning 345 ~luid 14.0
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The following e~amples illustrate the practice o~ the
invention~ which has industrial applicability for cosmetics,
toiletrieS and oil and gas recovery. E~am~le l represents
the best mode envisioned.
E~ample l
Five O.1 mole portions of Klucel~
hydro~ypropylcellulose, available from the Aqualon Company as
grades EF 80,000 mol. wt. JF (lso~ooo mol. wt.), MF (850,000
mol. wt.) and HF (1,150,000 mol. wt.), were prepared as
slurry suspensions in 750 ml methylene chloride and 250 ml
triethylamine. A 0.6 mole portion oE either palmitic acid
chloride or stearic acid chloride in 150 ml l,4-dio~ane was
added to each suspension. With constant stirring,
esterification was allowed to proceed or 24 hours at room
temperature. As the esterifieation proceeded, the suspension
became viscous and hard to stir. All portions reacted
equivalently to produce a palmitate or stearate ester of
hydro2ypropylcellulose. Purification and recovery were
accomplished by pouring the reaction mi~ture with stirring
into two liters of 85~ aqueous methanol and filtering the
precipitated product which was a gummy solid. The gummy
solid was then susp~nded in two lit~r of as~ methaQol and the
pH adjusted to 4 with dilut~ hydrochloric acid. The ester
was filtered, rewashed with aqucous methanol and dried under
vacuum at 50C.
Oil ~ase for Cle~nsing~Protective Skin Product:
W~
Isopropyl Palmitate 14.9
Lanolin Oil 23.9
Light Mineral Oil 4~.2
Dow Corning 345 Fluid 14.0
In general, palmitate esters had bett~r overall
solubilitY properties than stearate esters, particularly ~ith
respect to solution ~reeze-thaw and heat stability.
Table 1 contain~ comparative ~rookfield viscosity data
S (RvT) using Spindle 2 at 20 rpm in both isopropyl palmitate
(IPP) available ~rom Stepan, Drakeol mineral oil from Witco
and an oil based cosmetic formulation. All measurem~nts in
cps ~ mPa.s.
Table 1
Solution of Xl~c~ Es~c~ i~ Co~m~ic Solv~nt~
~olubiLi~y at l~ i~
~lucel~ Oil
~ample Gr~de ste~ Pr~k8Ql-9 ~rakeol-21 ~rakeol-3.,~
cps
1 JF palmitate 10 40 100 220 50
2 MF palmitate 10 85 125 400 155
3 HP palmitate - 200 350 675 135
4 EF stearata 10 90 - - S0
EF palmitate 10 45 - - S5
Tabl~ 2 contain~ comparative data in mineral oil.
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Table 2
Effect of Hydro~ypropylcellulose Ester
Concentration on Viscosity
Molecular viscosity in Mineral Oil
E3~mpl~ Wei~h~ palmitate ~iQn ~akeQl=~ PÆ~k~n_c~S
1140,000 JF 0.5 35 200
1.0 ~5 Z20
2.l~ 65 345
5.~) 170 ~00
2850,000 MF O.5 60 130
1.0 95 400
2.0 235 835
5.0 1510 4840
31,150,000 HF 0.5 105 355
1.0 180 675
2.0 780 1790
5.0 4810 1870
Weight Average molecular weight wa3 estimated by size
e~clusion chromatography.
As shown, not only are the hydroxypropylcellulose
stearates and palmitat~s soluble in the esters, oils and
lubricants us~ful in cosmetic formulation~; but they are also
quite ~fficient thickenQrs.
Laboratory ~amples o~ a hand cream were prepare~
incorporatinq hydro~ypropylcellulose palmitate. Satisfactory
thickening wa~ obtained with a 2% by weight addition.
Compared to a formulation for hand cream without thickener
with a viscosity of 100, the ~% hydroxypropylcellulose
palmitate addition gav~ a viscosity of 135. ~oth control and
e~perimental hand creams were clear and stable and able to
survive 3 freeze~thaw cycle.
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E~ample Z
Example 1 is repeated e~cept that the polysaccharide
used for esterification is either hydro~yethylcellulose,
hydro2ypropylguar or hydro~ypropyl starch. In all case~ a
stearate or palmitate ester of the polysaccharide is produced
The products were swellable but insoluble in mineral oil.
E~ample 3
Hydro~ypropylcellulose esters of acetic, octanoic and
lauric acids were prepared by technilqueA d~scribed in the
Background of the Invention. Hydro~1ypropylcellulose stearate
and palmitate were prepared as in Esample 1. Table 3
contains comparable solubility data for isopropyl myristate
(IPM) from Aldrich and light carnation mineral oil from Witco.
Table 3
IPM Mineral Oil
_ Ester Sol~kility ~Qlu~lity
Hydro~ypropylcellulose acetate Insoluble Swellable
Hydro2ypropylcellulose octanoate Swellable Swellable
Hydro~ypropylcellulose laurate Very Swsllabla Swellable
Hydro~ypropylcellulose palmitate Soluble Soluble
Hydrosypropylcellulose stearate Soluble Soluble
As shown, only the novel ester~ of the invention are
soluble in both IPM and mineral oil, wherea~ the prior art
esters are swellable at be~t. This illustrates that the
esters of the invention are suitable for us~ in cosmetic
formulation wherea~ th~ est@rs of the prior art are not.
Esample 4
A sample of Klucel~ JF hydro~ypropylcellulose available
from Aqualon was heated with slight e~cess palmitic acid in
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~oluene in the presence of p-toluenesulfonic acid and
azeotroPiCallY distilled to produce a colored polymer ~hich
was insoluble in Drakeol mineral oil.
E~ample 5
A sample of Klucel~ MF hydro~ypropylcellulose was
suspended in water/sodium hydroxide containing
tetrabutylammonium hydrogen sulfate as a phase transfer
catalyst. Palmitoyl chloride in methylene chloride was added
and the suspension was stirred for s~everal hours at room
temperature. The reaction mi~ture Wi3S diluted with methanol
and the reaction product was filtered, wa~hed and dried. A
white powder was obtained which was insoluble in mineral oils.
E2ample 6
Hydro~ypropylcellulose palmitate was prepar~d according
to th~ following transesterification reaction:
RCOOMe ~ R'OH ~ ---> RCOOR' + Me OH
Methyl palmitate HP~ ~PC palmitate
Methyl palmitate was reacted with hydro3ypropylcellulose
at 100C for 7 hours in toluene using sodium methoxide/sodium
ZO borohydride as a catalyst. The product obtained was soluble
in mineral oil.
E~ample 7
Hydro2ypropyl~ellulose (0.12 moles) was placed in a
three-nec~ round bottom flask equipped with a stirrer, Dean
Stark trap, thermometer, condenser, and a nitrogen inlet; 0.1
moles fatty acid, 250 ml toluene and 0.005 mole
para-toluenesulfonic acid were added. The reaction mixture
S~
as reflu~ed under nitrogen atmo~phere and water
azeotroPically removed at 110C for 7 hours. The residue
after decantation of solvent was pulverized in methanol,
filtered and dried. The ester was insoluble in mineral oil.
E~ample 8
E~ample 7 was repeated e~cept that a fatty acid methyl
ester was substituted for the fatty acid. Sirnilar results
were obtained. This illustrates the use o~ an acid catalysed
transesterification reaction.
E~ample 9
Klucel~ hydro~ypropylcellulose (0.1 mole) as used in
E~ample 1 was placed in a three neck round bottom flask
equipped with a mechanical stirrer, addition funnel,
thermometer and condenser. Pyridine (O.42 moles) was added.
Sufficient 1,4-dio~ane was then added to give a total liquid
to solid ratio of 16 to 1 after the addition of the acid
chloride. The hydrosypropylcellulose suspension was stirred
and 0.36 moles of acid chloride diluted with an equal weight
of 1,4-dio~ane was added over a period of 15 minutes. The
reaction misture was raised to 100C and held there with
continuous stirrinq for ~-8 hours. After cooling, the
reaction mi3ture wa~ diluted with methanol containing a small
amount of water to d~stroy e~ces~ acid chloride. The ester
was recovered and purified by dissolving in methylene
chloride, reprecipitated with methanol, washed with methanol
and dried.
Hydro3ypropylcsllulos~ stearates and palmitates were
produced with avera~e molecular weights of from 80,000 to
350,000.
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E~ample lO
A sample of hydro~ypropylcellulose palmitate, prepared
from Klucel~ MF hydro~ypropylcellulose as in E~ample l, wa~
tested for solubility in and viscosification of various C-5 to
C-lO fatty acid esters of mono-, di- and
poly-pentaerythritols. Hydro~ypropylcellulos~ palmitate
dissolved in and viscosified Hercolube~ 202 and Hercolube~ J
pentaerythritols available from Aqualon. The viscosity of
Hercolube~ 202 increased from 188 to 300 mPa.s and the
viscosity of Hercolube~ J increased from 40 to 140 mPa.~ using
a l~ by weight concentration of the ester.
In a similar manner various hydro~ypropylcellulose
palmitates from E~ample l were found to be soluble in and
thickened jojoba oil. Jojoba oil is an expensiv~ oil used in
cosmetic formulations such as shampoo and skin care products.
Conc~ntration3 of l to 3% provided viscou~ solution which were
thermally stable.
This egample further illustrates the thickening and/or
viscosification utility of the ester of the invention.
Example ll
E~ample l was repeated e~cept that
carbo~ym~thylhydro3ypropylcellulose with a carbo~ymethyl
substitution of 0.0~ - O.l~ was ~ub3tituted for
hydro~ypropylcellulo 9. Similar solubilitie3 were obtained.
Example 12
E~ample l i3 r~peated e~cept that
hydro~yethylhydro~ypropylcellulose, carbosymethylcellulose,
m~thylhydroxypropylcellulose, methylcellulose,
carbo~ymethylguar, and guar are substituted for
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dro~yproPylcellulose- Esters of stearic ac:id and palmitic
acid are formed in all cases.
E~ample 13
Several Klucel~ HPC palmitates (of Molecular Weight
~ 1.15 MM) were prepared in a similar procedure as in E~ample
1 e~cept the molar ratio of palmitic acid chloride to HPC was
varied ~rom 2 to 10. The esterificat:ion was allowed to
proceed 72 hours at room temperature. The estsnt of ester
substitution was conveniently determirled by infrared
spectroscopy.
Listed below are the calculated ratios of the ester band
at 1734 cm to the -OH band at 3470 cm.
~oles HPC/Palmitoyl ~hlorid~ Ra~iQL5~o ~ Lcm)~-O~ (347Q cmL
HPC (control) 0.04
1:2 0.~3
1:3 1.64
1:4 3.35
1:4 3.50
1:6 11.15
ZO 1:8 18.50
1:10 50.50
Tables 4 and 5 contain comparative 3rookfield (LVT)
viscosity data using spindle 2 at 30 rpm in various solvents.
All measurements are in cps ~ mPa.s.
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Table
Mol~L_~atio b Solukility at 1~ ~
Product L~a Fi~QL~n ~N Pr~kQO L ~lc --~b~---- d
51:3 14 27~ 80 44 49
1:4 320 150 100 - -
1:5 76 245 105 610 1000
1:6 12 23 80 - -
1:8 37 20 165
lol:lo 26 37 300 100 48
(a) IPP igopropyl palmitate availa:ble from Stepan
(b) Finsolv~ TN a C12-15 alkyl benzoate from Finte~ Company
(c) Drakeol-21 mineral oil available from Witco
(d) Hercolube~ A is a pentaerythritol estar available from
Aqualon Company
lS Though the Klucel~ HPC palmitates are not soluble in
pure silicone fluid~, such a~ Dow Corning'3 556
(phsnyltrimethicone) or 345 (cyclomethicone), they are soluble
in and thicken Finsolv ~N silicone solvent mi~tures as shown
in Table 5.
Tabl~ 5
Solubility in Fin~olv~ TN and DC 345 Mi2ture~ at 1~ Concentration
Molar Ratio
P~s~stFin~slv~ T~ pC 34~ v~o~i~Y
9 9
1:3.5 99.0 30.0 90 slight hazy
1:5 99.0 30.0 60 clear
1:3.5 49.5 49.5 17 2 phases
1:5 49.5 49.5 130 clear
1:5 24.75 74.25 56 slight hazy
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As shown, not only are the hydro~yproPY~LCellulose
palmitateS soluble in the esters, and oils u5eful in cosmetic
formulationS but also are quite efficient thickeners,
This e~ample illustrates the importance of the extent of
ester substitution on solubility and thickening properties in
different solvents.
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