Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
2002-02-26
2004-05-18
Richter, Johann (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
C568S671000
Reexamination Certificate
active
06737543
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to fatty polypropoxylate esters of aliphatic and aromatic monocarboxylic fatty acids. These compounds have unique pigment dispersion and emolliency properties. The fatty polypropoxylate esters of the present invention are particularly useful in the formulation of sunscreen lotions, sunscreen sprays, self-tanning compositions, make-ups and other pigmented products, cold creams, lotions, skin moisturizers, antiperspirants, after shaves, pre-electric shaves, topical pharmaceutical products, lipsticks and cleansing creams. The present invention further relates to topical preparations incorporating the fatty polypropoxylate esters of the present invention.
2. Prior Art
There has been an increased awareness among the public of the potential for skin damage from ultraviolet radiation, with frequent news reports of greater risk from sun-induced photo aging, melanoma, and other skin disorders. The contribution of UVA radiation as well as the widely recognized contribution of UVB radiation to skin damage has engendered the development of a broad range of sunscreen products from the cosmetic industry. Sophisticated sunscreen formulations have been developed which incorporate combinations of UVA and UVB absorbers in vehicles which provide wash-off resistance and enhanced esthetics. Because of the regulatory limitations on the levels at which organic sunscreens may be used in formulations and the desirability for high absorbency formulations (high SPF) with broad spectrum protection, the use of physical sunscreens in conjunction with organic sunscreens in formulations has increased greatly.
Physical sunscreens consist of very finely divided (micronized) inorganic metallic oxides, typically Titanium Dioxide or Zinc Oxide. These micronized physical sunscreens appear transparent on the skin by virtue of their small particle size. Similar to other finely divided particulate products used in cosmetic formulations such as pigments for foundations and makeups, micronized Zinc Oxide and micronized Titanium Dioxide are dispersed within the formulation by mixing, using either low-shear or high-shear methods. In order to make stable, cosmetically acceptable products, uniform dispersions must be produced, with all particles wetted out and which remain in suspension over a period of time without settling, gelling or agglomerating. Producing such stable suspensions has proved to be a challenge, although some successes have been achieved.
For example, U.S. Pat. No. 5,116,604 to Fogel describes the use of neopentanoate esters, in particular isoarachidyl neopentanoate, as cosmetic emollients for sunscreen products. U.S. Pat. No. 5,716,602 to Uick describes sunscreens formulated to include a water resistance agent and an insect repellent. One form has in an aqueous emulsion DEET, a sunscreen agent, an anionic surfactant, an alkylated PVP, and octyldodecyl neopentanoate. Both of these inventions use of Elefac I-205, i.e., Octyldodecyl Neopentanoate.
U.S. Pat. No. 5,476,643 to Fogel describes the use of two specific neopentyl glycol diesters, as wetting, dispersing, spreading and deterging agents for micronized TiO
2
, ZnO and other pigments. These esters, neopentyl glycol di-2-ethyl hexanoate and neopentyl glycol di-isostearate, are used in varying combinations and may also be used with an emulsifying agent for a water dispersible pigmented make-up cleaner composition.
Emollients such as Finsolv TN (C
12
-C
15
Alkyl Benzoate) and TRIVENT NP-13 (Tridecyl Neopentanoate) have also been employed with some success as dispersants for physical sunscreens, as have various glycols and propoxylates, such as PPG-3 Myristyl Ether. See for example, U.S. Pat. No. 5,928,631 to Lucas which describes a skin composition for controlling environmental malodors on the body. The composition comprises from about 0.1% to about 5%, by weight of a solubilized, water-soluble, uncomplexed cyclodextrin; from about 0.1% to about 36%, by weight of an oil phase selected from the group consisting of emollients, moisturizers, and skin protectants; one or more surfactants, and an aqueous carrier.
Still, there remains a need for superior dispersants with desirable esthetic properties for use in pigmented cosmetic compositions, particularly sunscreen formulations that contain physical sunscreens.
Additionally, since formulators often find it useful to fully disperse pigments, e.g., micronized metallic oxides, in a portion of the oil phase by high shear techniques such as milling, there is a need for forming oil phase dispersions which have a high solids content of pigments, particularly micronized metallic oxides, that are fluid.
OBJECTS AND SUMMARY OF THE INVENTION
It is a broad object of the present invention to provide a class of agents with superior dispersant properties suitable for use in the formulation of topical personal care products.
It is another object of this invention to provide compounds which are superior dispersants and have desirable esthetic properties for use in pigmented cosmetic compositions.
It is a further object of this invention to provide compounds which are superior dispersants, and have desirable esthetic properties for use in sunscreen formulations containing physical sunscreens.
It is yet another object of this invention to provide a dispersant that is useful for formulating by high shear techniques, such as milling, oil phase dispersions that have a high solids content of pigments and micronized metallic oxides.
It is a more specific object of this invention to provide dispersing agents having improved dispersant properties that are polypropoxylated fatty alcohol chains covalently bonded by ester linkages to aliphatic and aromatic monocarboxylic acids.
The aforedescribed objects and others are achieved through the present invention. Broadly, the invention is directed to certain aliphatic and aromatic monocarboxylic acid esters of polypropoxylated fatty alcohols. These compounds demonstrate unusual and unexpectedly superior properties as pigment dispersants, especially for micronized Zinc Oxide, e.g., Z-Cote HP-1 from BASF, micronized Titanium Dioxide, and uncoated pigments such as those used in foundations and makeup products. Additionally, these propoxylated alcohol esters can be used to produce uniform milled dispersions of pigments and micronized metallic oxide sunscreens that have exceptionally high solids content, exhibit unusual fluidity and when applied to the skin demonstrate a dry, elegant emolliency.
Generally, the fatty polypropoxylate esters of this invention are esters of an aliphatic or an aromatic monoacid formed by reacting an acid with a stoichiometric excess of a polypropoxylated fatty alcohol.
Broadly, the compounds of this invention have the following structural formula:
wherein R
1
is derived from a polypropoxylated fatty alcohol and has the structural formula:
wherein R
5
is a saturated or unsaturated, substituted or unsubstituted aliphatic or aromatic moiety containing from 4 to 24 carbon atoms, and x is an integer from 3 to 30; and
wherein R is derived from an aliphatic or aromatic monocarboxylic acid and has the structural formula:
wherein R
2
, R
3
and R
4
are independently selected from the group consisting of methyl, ethyl, propyl or isopropyl; or
wherein R
6
is H or OH or NH
2
or methyl or ethyl.
The present invention provides fatty polypropoxylate esters possessing exceptional pigment dispersant and esthetic emollient properties long sought by formulators for use in personal care and topical pharmaceutical preparations.
In accordance with another aspect of the present invention, there are provided compositions for topical application that include such the fatty polypropoxylate esters.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The emollient dispersants of the present invention are fatty polypropoxylate esters of aliphatic and aromatic monocarboxylic acids.
The aliphatic monocarboxylic acids suitable for preparing the compounds of the present invention contain from 2 to 24 carbon
DeMonico G. Frank
Needelman Sayer B.
Smith Maria K.
Smith Ronald J.
Puttlitz Karl J
Richter Johann
Zall Michael E.
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