Diesters of naphthalene dicarboxylic acid

Details Diesters of naphthalene dicarboxylic acid Diesters of naphthalene dicarboxylic acid

2000-01-24

2001-09-04

Gerstl, Robert (Department: 1626)

Organic compounds -- part of the class 532-570 series

Organic compounds

Carboxylic acid esters

Reexamination Certificate

active

06284916

ABSTRACT:

FIELD OF THE INVENTION
The present invention is directed to compositions for topical application to hair to impart gloss and to stabilize natural and/or synthetic hair color. More particularly, the present invention is directed to the use of diesters and/or polyesters of a naphthalene dicarboxylic acid that are surprisingly effective in imparting gloss and for stabilizing hair color against fading. The diesters and polyesters of naphthalene dicarboxylic acid stabilize natural hair color and hair dyes and impart gloss to the hair. In addition, as described in more detail in the parent application, now U.S. Pat. No. 5,993,789, the composition absorbs UV radiation.
BACKGROUND OF THE INVENTION AND PRIOR ART
It is well known that ultraviolet light having a wavelength between about 280 nm or 290 nm and 320 nm (UV-B) is harmful to human skin, causing bums that are detrimental to the development of a good sun tan. UV-A radiation, while producing tanning of the skin, also can cause damage, particularly to very lightly colored, sensitive skin, leading to reduction of skin elasticity and wrinkles.
Therefore, a sunscreen composition should include both UV-A and UV-B filters to prevent most of the sunlight within the full range of about 280 nm to about 400 nm from damaging human skin.
The UV-B filters that are most widely used commercially in sunscreen compositions are paramethoxycinnamic acid esters, such as 2-ethyohexyl paramethoxycinnamate, commonly referred to as octyl methoxycmnamate or PARSOL® MCX, having an ethyl radical extending from the 2 position of the hexyl long chain backbone; oxybenzone; and octyl salicylate.
The UV-A filters most commonly used in commercial sunscreen compositions are the dibenzoylmethane derivatives, particularly 4-(1,1-dimethylethyl)4′-methoxybenzoylmethane (PARSOL® 1789), and 4-isopropyl dibenzoylmethane (EUSOLEX 8020). Other dibenzoylmethane derivatives described as UV-A filters are disclosed in U.S. Pat. Nos. 4,489,057; 4,387,089 and 4,562,067 and 5,670,140, hereby incorporated by reference. It is also well known that the above described and most commonly used UV-A fiters, particularly the dibenzoylmethane derivatives, such as PARSOL® 1789, suffer in photochemical stability when used alone or in combination with the above-described most commercially used UV-B filters. Accordingly, when used alone or when combined with a UV-B filter, such as 2-ethylhexyl paramethoxycinnamate (PARSOL® MCX), oxybenzone and/or octyl salicylate, the PARSOL® 1789 becomes less photochemically stable necessitating repeated, frequent coatings over the skin for sufficient UV radiation protection.
In accordance with one embodiment of the present invention, it has been found, quite surprisingly, that by including a diester and/or polyester of one or more naphthalene dicbrboxylic acids of formula (I), into a cosmetic sunscreen formulation containing a UV-A dibenzyolmethane derivative, particularly PARSOL® 1789, and/or 4-isopropyl dibenzoylmethane (EUSOLEX 8020), the dibenzyolmethane derivative is photochemically stablized so that the dibenzyolmethane derivative-containing sunscreen composition with or without additional sunscreen agents, such as oxybenzone and/or octyl methoxycinnamate (ESCALOL 567), is more effective for filtering out UV-A radiation; the composition filters more UV-A radiation for longer periods of time; and, therefore, the sunscreen formulation need not be applied to the skin as frequently while maintaining effective skin protection against UV-A radiation.
In accordance with another important advantage of the present invention, it has been found that the diesters and polyesters of naphthalene dicarboxylic acids can also absorb UV light in the most damaging range of about 280-300 nm, especially over the 280 and 295 nm wavelength absorbance peaks shown in FIG.
9
.
By the addition of UV-B filter compounds, such as octyl methoxycinnamate, octyl salicylate, and/or oxybenzone, the compositions of the present invention can maintain surprisingly effective hair color protection and can protect against Uw radiation both in the UV-A and UV-B range, with or without common sunscreen additives, such as octocrylene, and/or titanium dioxide. The composition reaches a surprisingly high SPF without solid additives, such as titanium dioxide, thereby providing an exceptionally elegant feel that can be applied easily in a continuous coating for complete coverage and sunscreen protection. In the preferred compositions, the ratio of UV-A to UV-B filter compounds is in the range of about 0.1:1 to about 3:1, preferably about 0.1:1 to about 0.5:1, most preferably about 0.3:1 to about 0.5:1. Quite surprisingly, the preferred compositions of the present invention achieve unexpeetedly high SPF, e.g., higher than SPF 12 in one preferred composition, and higher than SPF 20 in another preferred composition, with the addition of surprisingly low amounts of other UV-B and UV-A filters to the PARSOL 1789, and without solid blocking compounds, such as TiO
2
.
In accordance with another embodiment of the present invention, the diesters and polyesters of naphthalene dicarboxylic acid, of the present invention, impart gloss to hair, and/or stabilize hair color against fading, particularly for hair containing a synthetic dye.
SUMMARY OF THE INVENTION
In brief, the present invention is directed to gloss-imparting and/or hair color protecting compounds comprising a diester and/or polyester of a naphthalene dicarboxylic acid, while providing UV absorption.
The active gloss-imparting and/or hair color stabilizing compounds of the present invention are diesters and polyesters of a naphthalene dicarboxylic acid. The diesters and polyesters are reaction products of (a) a naphthalene dicarboxylic acid having the structure:
and (b) an alcohol having the structure R
1
—OH, or a diol having the structure HO—R
2
—OH, or a polyglycol having the structure HO—R
3
—(—O—R
2
—)
m
—OH, wherein R
1
is an alkyl group, straight chain or branched, having 1 to 22 carbon atoms, R
2
and R
3
, same or different, are each an alkylene group, having 1 to 6 carbon atoms, and wherein m and n are each 1 to about 100, preferably 1 to about 10, more preferably 2 to about 7, or a mixture thereof.
A diester of the present invention has the structure:
wherein R
1
is as defined above.
The diesters and polyesters of naphthalene dicarboxylic acids of the present invention have the general formula (I):
wherein R
2
and R
3
, same or different, are each an alkylene group having 1 to 6 carbon atoms, and n=1 to about 100, preferably 1 to about 10, more preferably 2 to about 7.
Alternatively, the hair color stabilizing diesters and polyesters of the present invention can be end-capped with an alcohol or an acid. The end-capped polyesters have the structural formula (II):
wherein R
1
and R
2
and n are as defined above, with reference to formula (I). The two R
1
s in formula (II) may be the same or different.
The preferred diesters and polyesters of the present invention have a weight average molecular weight of about 244 to about 4000, and more preferably about 450 to about 1500. To achieve the full advantage of the present invention, the diester or polyester has a weight average molecular weight of about 500 to about 1000.
The naphthalene dicarboxylic acid is selected from the group consisting of 1,2-naphthalene dicarboxylic acid; 1,3-naphthalene dicarboxylic acid; 1,4-naphthalene dicarboxylic acid; 1,5-naphthalene dicarboxylic acid; 1,6-naphthalene dicarboxylic acid; 1,7-naphthalene dicarboxylic acid; 1, 8-naphthalene dicarboxylic acid; 2,3-naphthalene dicarboxylic acid; 2,6-naphthalene dicarboxylic acid; 2,7-naphthalene dicarboxylic acid, and mixtures thereof. Preferred dicarboxylic acids are the 2,6-, 1,5- and 1,8-naphthalene dicarboxylic acids.
The alcohol R
1
—OH can be, for example, methanol, ethanol, propanol, isopropyl alcohol, n-butanol, sec-butanol, isobutyl alcohol, tert-butyl alcohol, amyl alcohol, 1-hexanol, 1-octanol, 1decanol, isodecyl alcohol, 1-undecanol, 1-dodecanol, 1-tridecyl alcohol, 1-tetradecanol, 1-he

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