Colloid systems and wetting agents; subcombinations thereof; pro – Continuous liquid or supercritical phase: colloid systems;... – Primarily organic continuous liquid phase
Reexamination Certificate
2000-11-06
2003-04-15
Metzmaier, Daniel S. (Department: 1712)
Colloid systems and wetting agents; subcombinations thereof; pro
Continuous liquid or supercritical phase: colloid systems;...
Primarily organic continuous liquid phase
C516S056000, C516S907000, C516S908000, C424S401000, C424S060000, C514S939000
Reexamination Certificate
active
06548557
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to borax neutralized phosphate esters (mono and/or diesters, predominantly monoesters) which, when preferably at least partially neutralized separately, or in situ, are revealed as novel emulsfiers. Formulations are presented also which demonstrate a method for using the disclosed emulsifier to prepare stable emulsions of varying polarity and viscosity for use in a variety of dermatological applications, and/or wherever this type of emulsion may be useful.
BACKGROUND OF THE INVENTION
From 1982 to 1995 the inventor marketed and sold diethanolamine (DEA) cetyl phosphate under the commercial name Amphisol™, as a technical sales representative for the Givaudan Corp. (Division of Hoffmann-LaRoche). A group of formulations including sunscreens, skin treatment and pigmented lotions, among others were formulated and demonstrated to help sell the Amphisol™ to sunscreen and skin care companies.
In the early 1990's, in Europe and in the United States in 1999, DEA derivatives became suspect and then undesirable for use because of possible nitrosamine formation and health concerns which emerged from this information.
In or about 1992-93, Amphisol™ K (the potassium salt of cetyl phosphate) was introduced to replace the Amphisol™ and thus eliminate the DEA. Amphisol™ K however, never functioned as well as the original Amphisol™ in certain applications. To this day, there is a desire by all users of Amphisol™ (who favor its inherent properties in making unusually stable oil-in-water emulsions) for a direct replacement which does not incorporate diethanolamine.
As early as 1957 the inventor was aware of the use of a beeswax-borax system to prepare water-in-oil emulsions. Although the system functions reasonably well, problems emerged as beeswax varied from batch to batch and produced quality control problems. In addition, compositions utilizing beeswax often required strenuous mixing or homogenization to facilitate the production of a stable final formulation.
In order to address the shortcomings of beeswax/borax, the present inventor invented emulsions based upon the neutralization product of 12-hydroxystearic acid. These formulations are described in U.S. Pat. No. 5,993,861, issued Nov. 30, 1999.
These diverse teachings and the inventor's experience after almost 40 years of research, led to the inventor's attempt to find an adequate replacement for the diethanolamine used in (DEA) cetyl phosphate, inasmuch as the art had failed to find an adequate replacement.
OBJECTS OF THE INVENTION
It is an object of the invention to provide phosphate ester surface active agents which function as one or more of emulsifiers, wetters, spreaders, dispersers, detergents, foamers and emollients to provide storage stable emulsions, among other compositions.
It is a further object of the invention to provide phosphate ester emulsifiers which can function as a direct replacement for diethanolamine (DEA) cetyl phosphate (Amphisol™).
It is an additional object of the invention to provide a method of making emulsions which are easy to formulate and provide for accurate quality control.
It is yet another object of the invention to provide emulsions which can be used to readily manufacture personal care products including cosmetic products such as sunscreens, skin care lotions and creams as well as a myriad of other types of products.
These and/or other objects of the invention may be readily gleaned from the detailed description of the invention which follows.
BRIEF DESCRIPTION OF THE PRESENT INVENTION
The present invention relates to phosphate ester surface active agents of the structure:
Where R
1
and R
2
are H or a linear, cyclic or branch chained saturated or unsaturated C
8
-C
40
hydrocarbon group, more preferably a C
12
-C
22
hydrocarbon group, a —(R
3
—O)
m
—R
4
group, a —R
5
—O—(R
3
—O)
m
—R
4
group or a
group,
where R
3
is a C
2
-C
6
alkylene group, preferably an ethylene group, a propylene group or a mixture of ethylene and propylene groups, R
4
is H or a linear, cyclic or
branch chained saturated or unsaturated C
8
-C
40
group, a
group or a
group,
R
5
is a C
2
-C
18
alkylene group, R
6
is a linear, cyclic or branch chained saturated or unsaturated C
8
-C
40
hydrocarbon group and m is an integer from 0 to 150, preferably 1 to 20, R
7
is H or a linear, cyclic or branch-chained saturated or unsaturated C
1
-C
22
hydrocarbon group or a C
1
-C
22
alcohol group and R
8
is a C
1
-C
22
linear, cylic or branched chain saturated or unsaturated hydrocarbon group, with the proviso that when R
1
is H, R
2
cannot also be H and X is selected from the group consisting of NaHCO
3
, KaHCO
3
, Na
2
CO
3
, K
2
CO
3
, Na
2
HPO
4
, K
2
HPO
4 Na
2
B
4
O
7
.
Most preferably, R
1
is a C
16
H
34
or cetyl group (such that the surface active agent is the cetyl ester of phosphoric acid neutralized with a neutralizing agent, preferably as an alkaline salt having a pH in water at 5% w/w of about 8-13), R
2
is H and X is Na
2
B
4
O
7
. Thus, in preferred aspects according to the present invention, the neutralized surface active agent is an adduct (as distinguishable from a salt) prepared by the neutralization of a phosphoric acid ester containing one (neither R
1
nor R
2
is H) or two hydroxyl groups (R
1
or R
2
is H).
Surface active agents according to the present invention may be prepared by neutralizing a phosphoric acid ester in the presence of a neutralization compound preferably selected from the group consisting of Na
2
CO
3
, K
2
CO
3
, NaHCO
3
, KHCO
3
, Na
2
HPO
4
, K
2
HPO
4
, sodium tetraborate decahydrate (Borax NF), sodium tetraborate tetrahydrate and mixtures (for purposes of definition, the sodium tetraborate salts are considered “active boron salts” in the present invention), thereof. The surface active agents according to the present invention may be prepared in situ or separately, as isolated compounds. In situ means the phosphate ester is in the oil phase of the emulsion and the neutralizing salt is in the water phase. Then, the adduct is formed when the phases are mixed, thus forming the emulsifier in situ.
The surface active agents according to the present invention may be utilized to produce emulsions (primarily oil-in-water, but also water-in-oil as an auxiliary emulsifier in certain aspects) and for use in personal care products, such as creams and lotions, including pigmented formulations. The present compounds find particular use in emulsions, such as pigmented emulsions or moisturizing emulsions, among numerous others. The surface active agents according to the present invention which are emulsifiers exhibit excellent emulsification characteristics and, quite unexpectedly, also excellent emolliency. Surface active agents according to the present invention also may be used as wetters, spreaders, detergents, dispersers, solubilizers, and foamers as well as the previously mentioned emulsifiers and emollients. In addition, the surface active agents according to the present invention exhibit unusual solubility characteristics and can be dissolved in both hot water (70-75° C.) and hot oil (80-85° C.) at elevated temperatures. In addition, emulsifiers according to the present invention, when used in oil-in-water emulsions, form a water resistant film upon being deposited onto the skin- a characteristic which is excellent for sunscreens and other skin products. Emulsions according to the present invention exhibit consistent manufacturing and favorable storage stability even at high temperatures (50° C.).
Oil-in-water compositions according to the present invention comprise an oil phase and a water phase, with the oil phase generally ranging from about 5% to about 70% by weight of the emulsion composition and the water phase ranging from about 20% to about 90% by weight of the emulsion composition, the composition optionally containing additional components consistent with its use as an emulsion in a personal care product. More preferably, the oil phase in the composition ranges from about 10% to about 60% by weight of
Coleman Henry D.
Coleman Sudol Sapone P.C.
Metzmaier Daniel S.
Walter Merton Co., Inc.
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