Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
2000-07-07
2002-02-12
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
C528S025000, C528S031000, C528S033000, C556S445000, C556S449000, C556S450000, C556S453000, C556S478000, C556S487000, C556S489000
Reexamination Certificate
active
06346595
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to novel dimethicone copolyol compounds bearing ultra violet absorbing substituents. This invention also relates to compositions of matter, in particular cosmetic compositions, comprising the above novel compounds, which are especially well suited for the photoprotection of the skin and/or the hair against the deleterious effects of UV radiation, in particular solar radiation.
2. Description of the Prior Art
It is known to this art that light radiation of wavelengths of from 280 nm to 400 nm promotes tanning of the human epidermis, and that light radiation of wavelengths more particularly of from 280 nm to 320 nm, i.e., UV-B irradiation, causes skin burning and erythema which can impair the development of a natural tan. For these reasons, as well as for aesthetic reasons, there is an increasing demand for means of controlling this natural tanning in order to thereby control the color of the skin. This UV-B radiation must thus be screened from the skin.
It is also known to this art that UV-A radiation, of wavelengths of from 320 to 400 nm, which tan the skin, also adversely affects it, especially in the case of sensitive skin or skin which is continually exposed to solar radiation. UV-A rays especially cause a loss in the elasticity of the skin and the appearance of wrinkles, promoting premature skin aging. Such irradiation promotes triggering of the erythemal reaction or amplifies this reaction in certain individuals and may even be the source of phototoxic or photoallergic reactions. Thus, for aesthetic and cosmetic reasons, such as conservation of the natural elasticity of the skin, for example, an ever-increasing number of individuals wish to control the effect of UV-A rays on their skin, it is desirable to also screen out UV-A radiation.
A wide variety of compounds suited for photoprotection (UV-A and/or UV-B) of the skin are known to this art. Most of these are aromatic compounds exhibiting absorption of UV radiation in the region from 280 to 315 nm, or in the region from 315 to 400 nm, or in both of these regions. There is no good way known at present to modify the absorption properties of molecules to meet the specific needs, or to combine products to cover a wide range of UV wavelengths. Products heretofore known are typically formulated into antisun or sunscreen compositions which are in the form of an emulsion of oil-in-water type (namely, a cosmetically acceptable vehicle, diluent or carrier comprising a dispersing continuous aqueous phase and a dispersed discontinuous oily phase) and which thus contain, in various concentrations, one or more conventional lipophilic and/or hydrophilic organic screening agents. These are capable of selectively absorbing harmful UV radiation of specific wavelength, depending upon structure of such screening agents (and their amounts) being selected as a function of the desired sun protection factor SPF (the sun protection factor being expressed mathematically by the ratio of the irradiation time required to attain the erythema-forming threshold with the UV screening agent to the time required to attain the erythema-forming threshold in the absence of UV screening agent).
It is a long felt need to have a sunscreening agent that can absorb ultra violet radiation at specific desired wavelengths and be soluble in water or oil. In addition, these compounds exhibiting anti-UV activity must also have good cosmetic properties in compositions comprised thereof, good solubility in the usual solvents, and in particular fatty substances such as oils and greases, as well as good resistance to water and to perspiration (remanence).
U.S. Pat. No. 6,080,880 issued Jun. 27, 2000 teaches that grafting at least one cinnamamide, benzalmalonamide or benzalmalonate group onto a short-chain silicone molecule, in particular onto a linear silicone chain comprising not more than six Si atoms, novel compounds are obtained which obviate the drawbacks of the screening agents of the prior art, these novel compounds having, other than very high-performance screening properties, very good solubility in the usual organic solvents and in particular fatty substances such as oils, as well as excellent cosmetic properties, which render them particularly suitable for use as sunscreens in, or for the formulation of, cosmetic compositions suited for protecting the skin and/or the hair against the deleterious effects of ultraviolet radiation. The teachings state “And, taking account of their relatively small size, these novel compounds are easier to synthesize”.
After reviewing the teachings of U.S. Pat. No. 6,080,880 and specifically the findings that low molecular are desirable, we have surprisingly found that the making of specific compounds of the present invention, higher molecular weight compounds can be made that have the added attributes of being able to control the UV spectra, solubility in a variety of solvents and because of their molecular weight stay on the skin surface, rather than penetrate it as is the case with low molecular weight species.
3. Summary of the Invention
A major object of the present invention is the provision of novel silicone compounds that contain a UV-absorber and a polar alkoxylated group. The presence of the polar alkoxylated group not only has a dramatic effect upon solubility of the sunscreen, but also shifts the UV absorption properties, making it possible to synthesize products that have a specified UV absorption property. Since UV-B is the major area that causes problems with sun tanning, the products can be customized to have the desired water or oil solubility as well as the desired UV spectra. These novel compounds can be prepared to have the desired spectra, in addition to very good solubility in fatty materials, or aqueous systems, improved cosmetic properties, and which otherwise avoid those disadvantages and drawbacks to date characterizing the state of this art. This allows for the ability to formulate products heretofore unavailable to the cosmetic chemist.
Thus, the present invention features novel compounds having the formula
wherein;
a is an integer ranging from 0 to 2000;
b is an integer ranging from 1 to 20;
c is an integer ranging from 1 to 20;
d is an integer ranging from 0 to 20;
n is an integer ranging from 10 to 20;
w is an integer ranging 0 to 20;
x is an integer ranging 0 to 20;
y is an integer ranging 0 to 20;
z is an integer ranging 0
20
.
REFERENCES:
patent: 5466768 (1995-11-01), Yang
patent: 5542960 (1996-08-01), Grabowski
patent: 5986022 (1999-11-01), Austin et al.
patent: 6093222 (2000-07-01), Grabowski et al.
patent: 6162330 (2000-12-01), Northfleet et al.
patent: WO 86/05411 (1986-09-01), None
Dawson Robert
Robertson Jeffrey B.
Siltech LLC
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