Polyvinyl alcohol film-forming polymers for alcohol-based sunscreen formulations and methods of use thereof

Abstract

The present disclosure relates to a sunscreen formulation comprising: (a) a volatile solvent; and (b) at least one film-forming polymer comprising at least one of (i) a polyvinyl alcohol or (ii) a polyvinyl alcohol ester having other ester functions in addition to proprietary acetate esters, and (i) and (ii) being soluble in a volatile solvent, with the proviso that if the at least one film-forming polymer comprises a polyvinyl alcohol, if the at least one film-forming polymer comprises a polyvinyl alcohol, the at least one film-forming polymer is not soluble in the volatile solvent. The degree of hydrolysis of the polyvinyl alcohol is less than about 60%. Also disclosed are methods of using the sunscreen formulations to protect skin from damage of sunlight.

Description

[0001] Priority claim

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 355,177, filed on June 24, 2022, the entire contents of which are hereby incorporated by reference. Technical Field

[0003] The present disclosure relates to film-forming polymers for use in sunscreen formulations (compounds) and methods of using the sunscreen formulations. Background Art

[0004] The polymers used in sunscreen applications are usually made of synthetic materials. In order to make polymers suitable for such sunscreen applications, they should be soluble in alcohol-based (alcohol-based, based on alcohol) systems and / or systems containing a small amount of volatile organic compounds (VOCs), and in the case of aerosol-based sunscreen sprays, they should also be compatible with propellants. Conventional synthetic polymers are usually cheap and have acceptable performance. However, because they are non-biodegradable, conventional synthetic polymers are unsustainable. In addition, the cost and performance of regenerated synthetic polymers are not easy.

[0005] Therefore, there is a need for biodegradable sunscreen polymers that provide the same or better performance at a cost comparable to non-biodegradable alternatives and that are soluble in alcohol-based systems, such as ethanol-based systems, and optionally compatible with propellants such as hydrocarbons or dimethyl ether.

[0006] Sunscreen formulations based on biodegradable polyesters are the subject of our recent patent publications: US 2021 / 0259930; US 2021 / 0259945; and US 2021 / 0259946.

[0007] US 6,602,489 and WO 2006 / 018328 describe concentrated hair spray products comprising a film-forming polymer, which may be sold by Kuraray under the trade name Poval TM Polyvinyl alcohol for sale. Poval available TM The DH of the product is >99%. Kuraray usually provides these materials with a specific viscosity without indicating the molecular weight. For example, Poval TM LM-10HD is supplied with a viscosity of 4.5-5.7 MPa·s. Poval TM The viscosity of LM-20 is 3.0-4.0 MPa·s. However, it is interesting that the Poval TMThe number average molecular weight of LM-20 is about 20,000, but it is not known whether this is accurate. Polyvinyl alcohols may also be those available from Sekisui, for example under the trade name Selvol TM PVOH 523 / E 523 and Selvol TM PVOH 540 is available commercially with a DH of 88%.

[0008] US2015 / 0328130 describes a sunscreen composition comprising 0.1 to 10% of a nonlinear polymer selected from polyvinyl alcohol; and 40 to 80% of water. Exemplary compositions include various polyvinyl alcohols with a degree of hydrolysis of 86-99%; and at least 70% of water; but no ethanol.

[0009] AU 2017 / 204073 describes cosmetic compositions, in particular sun protection products, to which polyvinyl alcohol is added in order to facilitate the washing away of UV filters from textiles soiled with these compositions. According to the teaching, the addition of polyvinyl alcohol to the composition has a favorable effect on washability, reducing the staining of textiles caused by the composition. This effect is demonstrated by polyvinyl alcohol having a degree of hydrolysis of 86 to 89 mol %.

[0010] US 3,417,180 describes a hair spray formulation comprising polyvinyl acetate whose acetate groups are partially hydrolyzed to an extent of about 15% to 60%. Solubility in absolute ethanol is demonstrated to be up to 50% and solubility in halogenated hydrocarbon propellants (particularly trichlorofluoromethane and dichlorodifluoromethane) is demonstrated to be up to 48%. The use of hydrocarbon propellants and ethers is not taught or suggested, nor is the solubility of partially hydrolyzed polyvinyl acetate in such propellants demonstrated. Copolymers of partially hydrolyzed polyvinyl acetate with other monomers, including (meth)acrylic acid and crotonic acid, are theoretical (inferred), but not illustrated.

[0011] US 3,005,809 describes sheets or films of vinyl alcohol-crotonic acid copolymers.

[0012] The compatibility of film-forming polymers with alcohol-based (especially ethanol-based) sunscreen formulations remains a significant issue for formulators, and there is a pressing need for film-forming polymers that are biodegradable but at the same time soluble and compatible in alcohol-based systems.

[0013] It is therefore an object of the present disclosure to provide film-forming polymers which are biodegradable, exhibit excellent compatibility with alcohol-based formulations, especially ethanol-based formulations, and can therefore be formulated into stable sunscreen formulations providing biodegradability. Summary of the invention

[0014] In one embodiment, the present disclosure relates to a sunscreen formulation comprising:

[0015] (a) volatile solvents; and

[0016] (b) at least one film-forming polymer comprising at least one of: (i) polyvinyl alcohol or (ii) a polyvinyl alcohol ester having, in addition to the proprietary acetate, further ester functional groups, and (i) and (ii) being soluble in a volatile solvent; and

[0017] (c) at least one sunscreen active.

[0018] In a second embodiment, the present disclosure is directed to a method of protecting a user who is to be or has been exposed to sunlight from the damaging effects of exposure to sunlight, the method comprising applying to the user's skin an effective amount of a sunscreen formulation described herein. DETAILED DESCRIPTION

[0019] Polyvinyl alcohol ("PVOH") has the following general structure:

[0020]

[0021] And are characterized by pendant OH and acetate (CH3-CO-) groups / functional groups.

[0022] There are many known methods for preparing PVOH. However, from an industrial perspective, the current mainstream production method is as follows: polyvinyl acetate is prepared by free radical polymerization using vinyl acetate as a raw material, and then the polyvinyl acetate is hydrolyzed / esterified. Methanol or ethanol is mainly used as a solvent in the polymerization process / hydrolysis process.

[0023] The basic properties of PVOH are usually determined by the degree of polymerization and the degree of hydrolysis.

[0024] The degree of polymerization of PVOH is usually expressed as the viscosity average degree of polymerization obtained from the viscosity in water. In addition, when the degree of hydrolysis is expressed by repeating units m and n, the degree of hydrolysis can be expressed as follows: Degree of hydrolysis (mol%) = m / (n+m) × 100. This is a value expressing the proportion of vinyl alcohol units in all repeating units in mol%.

[0025] We found that the degree of hydrolysis is an important parameter for the solubility of the base polyvinyl alcohol in volatile solvents. On the other hand, when the base polyvinyl alcohol is derivatized with hydrophobic functional groups, the degree of hydrolysis is less important.

[0026] In one embodiment, the film-forming polymer comprises underivatized polyvinyl alcohol (also referred to herein as "base polyvinyl alcohol").

[0027] In a preferred embodiment, the degree of hydrolysis of the base polyvinyl alcohol is 60% or less, in particular 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, 101%, 102%, 103%, 104%, 105%, 106%, 107%, 108%, 109%, 110%, , 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59% and / or 60%; or a continuous sequence of percentages within this range, for example 1% to 60%, 1% to 59%, 2% to 59%, 2% to 58%, 3% to 58%, etc.

[0028] In another preferred embodiment, the degree of hydrolysis of the base polyvinyl alcohol is from 20% to 58%, in particular 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57% and / or 58%; or a continuous sequence of percentages within this range, for example 20% to 58%, 21% to 58%, 21% to 57%, 22% to 57%, 22% to 56%, etc.

[0029] In another preferred embodiment, the degree of hydrolysis of the base polyvinyl alcohol is from 35% to 58%, in particular 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57% and / or 58%; or a continuous sequence of percentages within this range, for example 35% to 58%, 36% to 58%, 36% to 57%, 37% to 57%, 37% to 56%, etc.

[0030] For ranges defined with the term "about", for example "less than about 60%" or "about 35% to about 58%", the range is expanded by up to 1%, preferably by up to 0.5%.

[0031] Once the base PVOH has been prepared, the base PVOH can be esterified by further reaction with a suitable functionalizing agent (e.g., an acid, anhydride, or lactone) according to methods known in the art. The esters can also be prepared by starting with vinyl acetate and other vinyl monomers in a specified ratio to form an intermediate copolymer with pendant acetate functional groups, and then selectively hydrolyzing the acetate groups to obtain the desired PVOH portion.

[0032] Thus, in another embodiment, the at least one film-forming polymer comprises a polyvinyl alcohol derivatized with additional ester functionalities different from the pendant OH and acetate groups characterizing the base polyvinyl alcohol.

[0033] As used herein, simply "polyvinyl alcohol" or "PVOH" or "base polyvinyl alcohol" or "base PVOH" without further modification refers to polyvinyl alcohol consisting only of pendant OH and acetate groups.

[0034] As used herein, "polyvinyl alcohol ester" or "PVOH ester" and the like refers to polyvinyl alcohol derivatized with additional ester functionality other than the pendant OH and acetate groups that characterize the base polyvinyl alcohol.

[0035] As noted above, one method of forming PVOH esters is to react the base PVOH with a suitable acid or a suitable acid derivative such as an anhydride or a lactone.

[0036] Suitable acids include linear, branched or cyclic, saturated or unsaturated, non-aromatic or aromatic mono- or polycarboxylic acids.

[0037] Exemplary acids that can be used for this purpose include, but are not limited to, propionic acid, butyric acid, valeric acid, isovaleric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, octadecanoic acid, neopentanoic acid, 2-ethylhexanoic acid, isononanoic acid, neononanoic acid, neodecanoic acid, Versatic Acid 9 (a highly branched nonanoic acid available from Hexion), Versatic Acid 10 (a highly branched decanoic acid available from Hexion), palmitic acid, benzoic acid, anthranilic acid, salicylic acid, phenylacetic acid, cinnamic acid, 4-chlorobenzoic acid, 1,4-dichlorobenzoic acid, 4-nitrobenzoic acid, 2,4-dinitrobenzoic acid, succinic acid, glutaric acid, adipic acid, octanedioic acid (suberic acid), acid), malonic acid, malic acid, octenylsuccinic acid, dodecenylsuccinic acid, azelaic acid, sebacic acid, pimelic acid, 2,2-dimethylsuccinic acid, 3,3-dimethylglutaric acid, 2,2-dimethylglutaric acid, maleic acid, fumaric acid and itaconic acid, n-heptanoic acid, n-octanoic acid, n-nonanoic acid, n-decanoic acid, n-lauric acid, n-myristic acid, n-stearic acid, oleic acid, oxalic acid, malonic acid, pimelic acid, azelaic acid, sebacic acid, benzene Formic acid, phthalic acid, citric acid, tartaric acid, lactic acid, malic acid, methyl benzoic acid, isophthalic acid, phthalic acid, terephthalic acid, trimellitic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, endomethylenetetrahydrophthalic acid, hexahydrophthalic acid, tetrachlorophthalic acid, methylhexahydrophthalic acid, substituted derivatives thereof, and mixtures of one or more of the foregoing.

[0038] Anhydrides of the above acids, if present, such as succinic anhydride, dimethyl and diethyl malonate, octenylsuccinic anhydride, dodecenylsuccinic anhydride, phthalic anhydride, trimellitic anhydride, tetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, may also be used.

[0039] In addition, certain materials that react in a manner similar to the acids to form esters are also useful. Such materials include lactones, including caprolactone, propiolactone, methyl caprolactone, butyrolactone.

[0040] As also described above, PVOH esters can be prepared by free radical polymerization of vinyl acetate and other vinyl monomers in a specified ratio to form an intermediate copolymer having pendant acetate functional groups, and then selectively hydrolyzing the acetate groups to obtain the desired PVOH portion. Polymerization methods known in the art such as, but not limited to, solution polymerization, bulk polymerization, precipitation polymerization, emulsion polymerization, and suspension polymerization can be used to polymerize vinyl acetate with other vinyl monomers. In a preferred embodiment, the polymerization is solution polymerization. In another preferred embodiment, the polymerization is suspension polymerization.

[0041] The disclosed sunscreen formulations additionally contain a volatile solvent. Examples of volatile solvents include one or more alcohols such as methanol, ethanol, and isopropanol; volatile hydrocarbons such as isooctane, isododecane, and isohexadecane; volatile aldehydes; volatile silicones; and volatile ketones such as acetone and methyl ethyl ketone. Hydrofluoroolefins may also be used as carrier solvents in the formulations.

[0042] In a preferred embodiment, the volatile solvent is an alcohol-based solvent system, wherein the alcohol-based solvent system comprises at least one C 1-6 Straight or branched chain alcohols.

[0043] In another preferred embodiment, the volatile solvent is a ketone.

[0044] In a particularly preferred embodiment, the volatile solvent is selected from ethanol, methanol, isopropanol, acetone, and mixtures thereof.

[0045] In another especially preferred embodiment, the sunscreen formulation comprises ethanol.

[0046] In a more preferred embodiment, the sunscreen formulation comprising ethanol is anhydrous. The terms "non-aqueous" and "anhydrous" are used interchangeably herein and refer to compositions containing less than about 10% by weight of water, especially less than about 5% by weight of water, or less than 1% by weight of water, or even 0% water.

[0047] In a most preferred embodiment, the sunscreen formulation comprises ethanol but does not contain any other alcohol or water.

[0048] In an alternative embodiment, where water is present, such small amounts of water may be desirable, for example, as a processing aid or co-solvent. In certain exemplary embodiments, the water content of the composition will be no greater than about 9% water in order to prevent the active ingredient from phase separation or precipitation from solution. One of ordinary skill in the art will recognize that different active ingredients have different tolerances to water in solution and will adjust the water content accordingly.

[0049] In one embodiment, the polymer is completely soluble in ethanol or a mixture consisting mainly of ethanol and containing 0-20% by weight, preferably 5-10% by weight, of water.

[0050] In another embodiment, the polymer is completely soluble in ethanol.

[0051] In another embodiment, the polymer is completely soluble in anhydrous ethanol.

[0052] In another embodiment, after incorporating the polymer into anhydrous ethanol, the polymer is completely dissolved in the solvent immediately. As used in this disclosure, the phrase "immediately" means one hour or less, preferably half an hour or less, most preferably 15 minutes or less.

[0053] In another embodiment, the polymer remains completely soluble in anhydrous ethanol 24 hours after incorporation of the polymer into the solvent.

[0054] In a particularly preferred embodiment,

[0055] (a) upon incorporation of the polymer into anhydrous ethanol, the polymer immediately and completely dissolves in the solvent; and

[0056] (b) 24 hours after the polymer was incorporated into anhydrous ethanol, the polymer was completely dissolved in the solvent.

[0057] In an even more preferred embodiment, the polymer comprises polyvinyl alcohol or an ester thereof, wherein if the polymer comprises underivatized polyvinyl alcohol, the degree of hydrolysis of the polyvinyl alcohol is 35-58% and:

[0058] (a) upon incorporation of the polymer into anhydrous ethanol, the polymer immediately and completely dissolves in the solvent; and

[0059] (b) 24 hours after the polymer was incorporated into anhydrous ethanol, the polymer was completely dissolved in the solvent.

[0060] In a more preferred embodiment, the polymer comprises polyvinyl alcohol or an ester thereof, wherein if the polymer comprises underivatized polyvinyl alcohol, the degree of hydrolysis of the polyvinyl alcohol is 35-45% and:

[0061] (a) upon incorporation of the polymer into anhydrous ethanol, the polymer immediately and completely dissolves in the solvent; and

[0062] (b) 24 hours after the polymer was incorporated into anhydrous ethanol, the polymer was completely dissolved in the solvent.

[0063] In an even more preferred embodiment, the polymer comprises polyvinyl alcohol or an ester thereof, wherein if the polymer comprises underivatized polyvinyl alcohol, the degree of hydrolysis of the polyvinyl alcohol is 38-42% and:

[0064] (a) upon incorporation of the polymer into anhydrous ethanol, the polymer immediately and completely dissolves in the solvent; and

[0065] (b) 24 hours after the polymer was incorporated into anhydrous ethanol, the polymer was completely dissolved in the solvent.

[0066] In one embodiment, the sunscreen formulation further comprises a propellant.

[0067] In certain embodiments of the present disclosure, the disclosed formulation can be stored in a pressure vessel by combining with a propellant, and the present disclosure also extends to a pressure vessel comprising the disclosed formulation. The formulation stored in this way can be used by opening the valve in the container to release the propellant and composition usually in the form of spray or mist. The propellant used in the composition can be any suitable gas or gas combination, which can be compressed or liquefied in a distribution spray can, expanded or volatilized into a vapor or gaseous form under exposure to ambient temperature and pressure conditions, so as to deliver the composition in an aerosol form. Suitable propellants include hydrocarbons with 1 to 5 carbon atoms, including but not limited to methane, ethane, propane, isopropyl ether, butane, isobutane, butylene, pentane, isopentane, neopentane and pentene, hydrofluorocarbons (HFC), including but not limited to 1,1-difluoroethane (HP 152a), chlorofluorocarbons (CFCs), hydrofluoroolefins (HFOs), nitrogen, ethers (including dimethyl ether) and any mixture thereof. Those of ordinary skill in the art recognize that in a closed container such as an aluminum can or a glass bottle, a propellant such as dimethyl ether condenses into a liquid state at ambient temperature. Therefore, the composition in the aerosol container is a liquid formulation that can contain dissolved propellant, undissolved liquid propellant, and gaseous propellant. All of these are under pressure due to the vapor pressure of the propellant. In the practice of this aspect of the present disclosure, the propellant can be present in an amount of up to about 90% by weight, preferably about 2% by weight to about 50% by weight, more preferably about 5% by weight to about 40% by weight, more preferably about 30% by weight, based on the total weight of the aerosol composition.

[0068] In another embodiment, the propellant is a hydrocarbon derived ether.

[0069] In another embodiment, the propellant is dimethyl ether (DME).

[0070] In a preferred embodiment, the polymer is fully compatible with DME.

[0071] In a particularly preferred embodiment,

[0072] (a) After the polymer is incorporated into anhydrous ethanol, the polymer immediately and completely dissolves in the solvent;

[0073] (b) the polymer is completely dissolved in anhydrous ethanol 24 hours after the polymer is incorporated into the solvent; and

[0074] (c) The polymer is completely compatible with DME.

[0075] In an even more preferred embodiment, the polymer comprises polyvinyl alcohol or an ester thereof, wherein if the polymer comprises underivatized polyvinyl alcohol, the degree of hydrolysis of the polyvinyl alcohol is 35-58% and:

[0076] (a) After the polymer is incorporated into anhydrous ethanol, the polymer immediately and completely dissolves in the solvent;

[0077] (b) the polymer is completely dissolved in anhydrous ethanol 24 hours after the polymer is incorporated into the solvent; and

[0078] (c) The polymer is completely compatible with DME.

[0079] In a more preferred embodiment, the polymer comprises polyvinyl alcohol or an ester thereof, wherein if the polymer comprises underivatized polyvinyl alcohol, the degree of hydrolysis of the polyvinyl alcohol is 35-45% and:

[0080] (a) After the polymer is incorporated into anhydrous ethanol, the polymer immediately and completely dissolves in the solvent;

[0081] (b) the polymer is completely dissolved in anhydrous ethanol 24 hours after the polymer is incorporated into the solvent; and

[0082] (c) The polymer is completely compatible with DME.

[0083] In an even more preferred embodiment, the polymer comprises polyvinyl alcohol or an ester thereof, wherein if the polymer comprises underivatized polyvinyl alcohol, the degree of hydrolysis of the polyvinyl alcohol is 38-42% and:

[0084] (a) After the polymer is incorporated into anhydrous ethanol, the polymer immediately and completely dissolves in the solvent;

[0085] (b) the polymer is completely dissolved in anhydrous ethanol 24 hours after the polymer is incorporated into the solvent; and

[0086] (c) The polymer is completely compatible with DME.

[0087] In another embodiment, the propellant is a hydrofluorocarbon.

[0088] In another embodiment, the propellant is 1,1-difluoroethane.

[0089] In a preferred embodiment, the polymer is completely compatible with 1,1-difluoroethane.

[0090] In a particularly preferred embodiment,

[0091] (a) After the polymer is incorporated into anhydrous ethanol, the polymer immediately and completely dissolves in the solvent;

[0092] (b) the polymer is completely dissolved in anhydrous ethanol 24 hours after the polymer is incorporated into the solvent; and

[0093] (c) The polymer is completely compatible with 1,1-difluoroethane.

[0094] In a more preferred embodiment, the polymer comprises polyvinyl alcohol or an ester thereof, wherein if the polymer comprises underivatized polyvinyl alcohol, the degree of hydrolysis of the polyvinyl alcohol is 35-58% and:

[0095] (a) After the polymer is incorporated into anhydrous ethanol, the polymer immediately and completely dissolves in the solvent;

[0096] (b) the polymer is completely dissolved in anhydrous ethanol 24 hours after the polymer is incorporated into the solvent; and

[0097] (c) The polymer is completely compatible with 1,1-difluoroethane.

[0098] In a more preferred embodiment, the polymer comprises polyvinyl alcohol or an ester thereof, wherein if the polymer comprises underivatized polyvinyl alcohol, the degree of hydrolysis of the polyvinyl alcohol is 35-45% and:

[0099] (a) After the polymer is incorporated into anhydrous ethanol, the polymer immediately and completely dissolves in the solvent;

[0100] (b) the polymer is completely dissolved in anhydrous ethanol 24 hours after the polymer is incorporated into the solvent; and

[0101] (c) The polymer is completely compatible with 1,1-difluoroethane.

[0102] In an even more preferred embodiment, the polymer comprises polyvinyl alcohol or an ester thereof, wherein if the polymer comprises underivatized polyvinyl alcohol, the degree of hydrolysis of the polyvinyl alcohol is 38-42% and:

[0103] (a) After the polymer is incorporated into anhydrous ethanol, the polymer immediately and completely dissolves in the solvent;

[0104] (b) the polymer is completely dissolved in anhydrous ethanol 24 hours after the polymer is incorporated into the solvent; and

[0105] (c) The polymer is completely compatible with 1,1-difluoroethane.

[0106] In one embodiment, the sunscreen formulation disclosed herein is dispensed from a bag-on-valve device. Typically, a bag-on-valve device includes a spray can equipped with an aerosol valve and including a welded bag. The product is placed in the bag, and the propellant is filled in the space between the bag and the can. When the spray button is pressed, the product is dispensed by simply squeezing the bag through the propellant.

[0107] Typically, the compositions according to the present disclosure are prepared as non-aqueous, volatile solvent based compositions. However, in some embodiments, the compositions comprise a single liquid phase that may further comprise dispersed particles (eg, UV active agent in particulate form).

[0108] We have discovered that, in certain circumstances, the base polyvinyl alcohol polymer described above containing primarily only pendant alcohol and acetate groups can be derivatized without loss of solubility in volatile solvents.

[0109] The solubility of derivatized polyvinyl alcohols in such volatile solvents can be evaluated using the test protocol outlined in the Examples below.

[0110] As mentioned above, the main production methods for producing polyvinyl alcohol include making polyvinyl acetate by free radical polymerization using vinyl acetate as a raw material and then hydrolyzing the polyvinyl acetate. Derivatives can then be prepared, for example, by (a) reacting polyvinyl alcohol with an acid, anhydride or lactone; or (b) directly (i) polymerizing a polymerizable monomer precursor (e.g., vinyl alkanoate) of a derivatized functional group with vinyl acetate, followed by (ii) hydrolysis to produce an alcohol functional group with any desired degree of hydrolysis.

[0111] In one embodiment, polyvinyl alcohol is derivatized with crotonic acid, for example by copolymerizing crotonic acid with vinyl acetate, followed by hydrolysis / transesterification of the product to obtain the desired polyvinyl alcohol derivative. In a preferred embodiment, the product is a partially hydrolyzed vinyl acetate-crotonic acid copolymer comprising pendant carboxylic acid groups and pendant hydroxyl groups condensed together to form an internal γ-lactone functionality.

[0112] In one embodiment, the polyvinyl alcohol polymer is derivatized with succinic acid, for example by reacting polyvinyl alcohol soluble in a volatile solvent with succinic anhydride.

[0113] In another embodiment, the polyvinyl alcohol polymer is derivatized with caprolactone, for example by reacting polyvinyl alcohol soluble in a volatile solvent with the caprolactone.

[0114] In another embodiment, the polyvinyl alcohol polymer is derivatized with pivalic acid, for example by copolymerizing vinyl pivalate with vinyl acetate, followed by hydrolysis / transesterification of the product to obtain the desired polyvinyl alcohol derivative.

[0115] In another embodiment, the polyvinyl alcohol polymer is derivatized with neononanoic acid, for example by copolymerizing vinyl neononanoate with vinyl acetate, followed by hydrolysis / transesterification of the product to obtain the desired polyvinyl alcohol derivative.

[0116] In another embodiment, the polyvinyl alcohol polymer is derivatized with Versatic Acid 9, for example by copolymerizing the vinyl ester of Versatic Acid 9 (eg, VeoVa 9 from Hexion) with vinyl acetate and then hydrolyzing / transesterifying the product to obtain the desired polyvinyl alcohol derivative.

[0117] In another embodiment, the polyvinyl alcohol polymer is derivatized with neodecanoic acid, for example by copolymerizing vinyl neodecanoate with vinyl acetate, followed by hydrolysis / transesterification of the product to obtain the desired polyvinyl alcohol derivative.

[0118] In another embodiment, the polyvinyl alcohol polymer is derivatized with Versatic Acid 10, for example by copolymerizing vinyl neodecanoate (eg, VeoVa 10 from Hexion) with vinyl acetate, followed by hydrolysis / transesterification of the product to obtain the desired polyvinyl alcohol derivative.

[0119] In another embodiment, the polyvinyl alcohol polymer is derivatized with 2-ethylhexanoic acid, for example by polymerizing vinyl 2-ethylhexanoate with vinyl acetate, followed by hydrolysis / transesterification of the product to obtain the desired polyvinyl alcohol derivative.

[0120] In another embodiment, the polyvinyl alcohol polymer is derivatized with lauric acid, for example by polymerizing vinyl laurate with vinyl acetate, followed by hydrolysis / transesterification of the product to obtain the desired polyvinyl alcohol derivative.

[0121] In another embodiment, the poly(vinyl alcohol) polymer is derivatized with carboxylic acids pendant to the polymer backbone to provide internal lactone (cyclic ester) moieties.

[0122] In a preferred embodiment, a carboxylic acid pendant to the polymer backbone is reacted with an alcohol pendant to the γ-carbon relative to the carbon pendant to the carboxylic acid to form an internal γ-lactone (five-membered ring).

[0123] In a preferred embodiment, the carboxylic acid pendant to the polymer backbone is an acrylic acid or crotonic acid residue obtained after copolymerization of acrylic acid or crotonic acid, respectively, with vinyl acetate and optionally one or more vinyl alkanoates and subsequent hydrolysis to produce alcohol functionality to any desired degree of hydrolysis.

[0124] In a more preferred embodiment, the carboxylic acid pendant to the polymer backbone is a crotonic acid residue obtained after copolymerization of crotonic acid with vinyl acetate and optionally one or more vinyl alkanoates and subsequent hydrolysis to produce alcohol functionality at any desired degree of hydrolysis.

[0125] In a most preferred embodiment, the carboxylic acid pendant to the polymer backbone is a crotonic acid residue obtained after copolymerization of crotonic acid with vinyl acetate and optionally one or more vinyl alkanoates and subsequent hydrolysis to produce alcohol functionality with any desired degree of hydrolysis, and the internal lactone formed is a gamma-lactone. In an especially preferred embodiment, the polyvinyl alcohol is derivatized with 1 to 20% by weight of crotonic acid gamma-lactone, based on 100% by weight of the polyvinyl alcohol polymer.

[0126] In a more preferred embodiment, the polyvinyl alcohol is derivatized with 2-13% by weight of crotonic acid gamma-lactone based on 100% by weight of the polyvinyl alcohol polymer.

[0127] In an even more preferred embodiment, the polyvinyl alcohol is derivatized with 6-12 wt% of crotonic acid gamma-lactone, based on 100 wt% of the polyvinyl alcohol polymer.

[0128] In a most preferred embodiment, the polyvinyl alcohol is derivatized with 6-12% by weight of crotonic acid gamma-lactone, based on 100% by weight of the polyvinyl alcohol polymer, and the degree of hydrolysis thereof is 35-50%.

[0129] It should be noted that the carboxylic acid pendant to the polymer is an acrylic acid or crotonic acid residue obtained after copolymerization of acrylic acid or crotonic acid, respectively, with vinyl acetate and optionally one or more vinyl alkanoates and subsequent hydrolysis to produce alcohol functional groups at any desired degree of hydrolysis, and it is known that the carboxylic acid pendant to the polymer forms lactones with the alcohol functional groups pendant to the polyvinyl alcohol polymer. For this reason, steps are sometimes taken to inhibit the formation of lactones. However, in a preferred embodiment, no steps are taken to inhibit the formation of lactones.

[0130] In one embodiment, film-forming polymers are incorporated into sunscreen formulations to impart water resistance properties thereto.

[0131] In one embodiment, the water-resistant polymer is incorporated into the sunscreen formulation in an amount of 0.1 to 10% by weight, based on the total weight of the formulation.

[0132] In another embodiment, the water-resistant polymer is incorporated into the sunscreen formulation in an amount of 0.5 to 5% by weight, based on the total weight of the formulation.

[0133] In yet another embodiment, the water-resistant polymer is incorporated into the sunscreen formulation in an amount of 1 to 3% by weight, based on the total weight of the formulation.

[0134] The disclosed sunscreen formulations additionally include at least one sunscreen active agent. For the purposes of this disclosure, a "sunscreen active agent" is a material used alone or in combination with other such materials that is considered to be useful as an active sunscreen ingredient based on its ability to absorb ultraviolet radiation. Such compounds are typically described by their ability to act as ultraviolet active agents and their performance in different spectral regions (referred to as UV-A, UV-B, or UV-A / UV-B). The addition of active agents to formulations for human use typically requires approval from regulatory agencies. Active agents that have been or are currently approved for use as sunscreens in the United States include organic and inorganic substances, including but not limited to p-aminobenzoic acid, avobenzone, cinoxate, dioxybenzone, homosalate, menthyl anthranilate, octyl salicylate, oxybenzone, padimate O, phenylbenzimidazole sulfonic acid, sulisobenzone, triethanolamine salicylate, titanium dioxide, zinc oxide, diethanolamine methoxycinnamate, digalloy trioleate, ethyl dihydroxypropyl PABA, glyceryl aminobenzoate, 2-hydroxy-1,4-naphthoquinone with dihydroxyacetone, and red petrolatum. Examples of other sunscreen active ingredients that have not been approved in the United States but are permitted for sale outside the United States include ethylhexyl triazone, dioctyl butyrylamino triazone, benzalmalonate polysiloxane, terephthalylidene dicamphor sulfonic acid, disodium phenyl dibenzimidazole tetrasulfonate, diethylamino hydroxybenzoyl hexyl benzoate, bis diethylamino hydroxybenzoyl benzoate, bis benzoxazolyl phenyl ethylhexyl imino triazine, drometrizole trisiloxane, methylene bis benzotriazolyl tetramethylbutylphenol, bis ethylhexyloxyphenol methoxyphenyl triazine, 4-methylbenzylidene camphor, and isopentyl 4-methoxycinnamate. However, as the list of currently approved sunscreen agents continues to expand, one of ordinary skill in the art will recognize that the present disclosure is not limited to sunscreen actives currently approved for use in humans, but is also readily applicable to sunscreen actives that may be permitted for use in the future.

[0135] In Europe, sunscreen actives that have been approved and are therefore useful according to the present disclosure include, but are not limited to: benzophenones, such as 3-benzophenone (BP3) and 4-benzophenone (BP4); salicylates, such as homosalate (HMS) and 2-ethylhexyl salicylate (EHS); p-aminobenzoic acid and its derivatives, such as ethylhexyl dimethyl p-aminobenzoate (OD-PABA) and 4-p-aminobenzoic acid (PABA); benzimidazole derivatives, such as phenylbenzimidazole sulfonic acid (PMDSA) and disodium phenyldibenzimidazole tetrasulfonate (bisdisulizoledisodium); triazines, such as ethylhexyl triazine ketone (OT), diethylhexyl butyrylamino triazone (DBT) and bis-ethylhexyloxyphenol methoxyphenyl triazine (EMT); benzotriazoles, such as drometrizole trisiloxane (DRT) and methylene bisbenzotriazolyl tetramethylbutylphenol (MBP, Biscotrizole); dibenzoylmethane derivatives, such as 4-tert-butyl-4'-methoxydibenzoylmethane (BM-DBM, Avobenzone); cinnamate esters, such as ethylhexyl methoxycinnamate (OMC) and isoamyl p-methoxycinnamate (IMC, Amiloxate); and camphor derivatives, such as terephtalydene dicamphorsulfonic acid (Terephtalydene dicamphor sulfonic acid) (PDSA), 3-benzylidene camphor (3BC), benzalkonium camphor sulfonic acid (BCSA), 4-methylbenzylidene camphor (4-MBC), polyacrylamidomethylbenzylidene camphor (PBC), and camphor benzalkonium chloride methylsulfate (CBM).

[0136] In one embodiment of the present disclosure, the sunscreen active comprises a photoprotective effective amount of particles of at least one inorganic pigment or nanopigment, non-limiting examples of which include titanium dioxide, zinc oxide, iron oxide, zirconium oxide, cerium oxide, or mixtures thereof.

[0137] In a particularly preferred embodiment, the at least one sunscreen active is selected from avobenzone, homosalate, octylsalicylate, octocrylene and oxybenzone.

[0138] Typically, the content of sunscreen active agents in sunscreen formulations is an amount known in the art to effectively protect users who are to be exposed or have been exposed to the sun from the damaging effects of exposure to the sun. Typically, these amounts are 1-25% by weight, preferably 3-25% by weight, based on the total weight of the sunscreen formulation.

[0139] Additionally, the solvent may include varying amounts of oils such as mineral oil or vegetable oils as co-solvents or "emollients" as described herein.

[0140] Emollients may include any suitable oils, solvents, esters, triglycerides, etc. suitable for the end use application. For sunscreen products, typical emollients include triheptanoin, isopropyl palmitate, triheptanoin (and) C13-C16 isoparaffin, heptyl undecylenate, caprylic / capric triglyceride, diisooctyl succinate, C13-C16 isoparaffin (and) heptyl undecylenate, C12-C15 alkyl benzoate, caprylic / capric triglyceride and other suitable esters.

[0141] In addition to the polyvinyl alcohol described herein, the sunscreen formulation may additionally include other film-forming polymers. By way of example only, such other film-forming polymers may be selected from: polyglucose polymers based on starch esters, such as described in US11,135,148, the entire contents of which are hereby incorporated herein by reference; polyesters, such as described in US 2021 / 0259930, US 2021 / 0259945 and US 2021 / 0259946, the entire contents of which are hereby incorporated herein by reference; and N- alkyl (meth) acrylamide copolymers, such as described in US 20180098930, the entire contents of which are hereby incorporated herein by reference. Other examples of suitable other film-forming polymers include: based on the total weight of the film-forming polymer, a film-forming polymer containing at least 5% by weight of an acid-containing monomer. In a preferred embodiment, the film-forming polymer contains at least 5% by weight of a carboxylic acid-containing monomer. Non-limiting examples of these monomers are acrylic acid, crotonic acid, methacrylic acid, maleic acid, itaconic acid, and combinations and mixtures thereof. Other film-forming polymers, whether synthetic or natural, may be used together with the above acid-containing polymers. Non-limiting examples of these other film-forming polymers are: and LV-71 polymer (octylacrylamide / acrylates / butylaminoethyl methacrylate copolymer), Polymer (Acrylates / Octyl Acrylamide Copolymer), 0 / 55 and BALANCE Polymer (Acrylate Copolymer), 47 polymer (octylacrylamide / butylaminoethyl methacrylate copolymer), 28-2930 polymer (VA / crotonate / vinyl neodecanoate copolymer), 28-1310 polymer (VA / crotonate copolymer), Polymer (Sodium Polystyrene Sulfonate), DynamX Polymer (Polyurethane-14 (and) AMP-Acrylates Copolymer), RESYN Polymer (Acrylates / Octyl Acrylamide Copolymer), STRUCTURE 2001 (Acrylates / Steareth-20 Itaconate Copolymer) and 3001 (Acrylates / Ceteth-20 Itaconate Copolymer); from ISP (PVM / MA half ethyl ester copolymer), GANEX (Butyl PVP), GANEX (PVP / hexadecene copolymer), V-220 (PVP / eicosene copolymer), WP-660 (triathionyl PVP), A425 (butyl ester of PVM / MA copolymer), AN-119 PVM / MA copolymer, GANTREZES (ethyl ester of PVM / MA copolymer), GANTREZ ES425 (butyl ester of PVM / MA copolymer), GAFFIX (vinyl caprolactam / PVP / dimethylaminoethyl methacrylate copolymer), (Polyquaternium-11), GAFQUAT (Polyquaternium-28), AQUAFLEX XL-306 (Polyimide-1), AQUAFLEX (PVP / vinyl caprolactam / DMAPA acrylate copolymer), AQUAFLEX (isobutylene / ethylmaleimide / hydroxyethylmaleimide copolymer), ALLIANZ (Acrylates / C1-2 Succinate / Hydroxyacrylate Copolymer), STYLEZE (PVP / DMAPA acrylate copolymer), STYLEZE (VP / Acrylates / Lauryl Methacrylate Copolymer), STYLEZE (Polyquaternium-55), copolymer series (PVP / dimethylaminoethyl methacrylate copolymer), ADVANTAGE and ADVANTAGE (vinyl caprolactam NP / dimethylaminoethyl methacrylate copolymer), ADVANTAGE PLUS (VA / butyl maleate / isobornyl acrylate copolymer), Antaron ECo (ethyl cellulose); BASF's ULTRAHOLD STRONG (acrylic acid / ethyl acrylate / tert-butyl acrylamide), LUVIMER (tert-butyl acrylate / ethyl acrylate / methacrylic acid), LUVIMER 36D (ethyl acrylate / tert-butyl acrylate / methacrylic acid), LUVIQUAT (Polyquaternium-16), LUVIQUAT (Polyquaternium-16), LUVISKOL K30(PVP), LUVISKOL (PVP), LUVISKOL (PVP / VA copolymer), LUVISKOL (PVPNA copolymer), LUVISKOL LUVISET (Polyurethane-1), Clear (VP / methacrylamide dimethylimidazole copolymer), LUVIFLEX (Acrylate Copolymer), ULTRAHOLD (acrylate / acrylamide copolymer), Plus(polyvinyl caprolactam), Silk (PEG / PPG-25 / 25 Dimethicone / Acrylates Copolymer); from Amerchol DR-25 (acrylic acid / methacrylic acid / acrylate / methacrylate); ACUDYNE from Rohm & Haas (Acrylic acid / methacrylic acid / acrylate / methacrylate / hydroxy ester acrylate; DIAFORMER from Mitsubishi and distributed by Clariant DIAFORMER and DIAFORMER (Methacryloylethyl Betaine / Acrylates Copolymer), ACUDYNE (acrylates / hydroxy acrylates copolymer), ACUDYNE SCP (vinyl carboxamide / AMPSA / methacrylates copolymer) and Rheology modifiers; FIXOMER from ONDEO Nalco and FIXOMER (INCI name: Methacrylic Acid / Sodium Acrylamidomethylpropane Sulfonate Copolymer); FIXATE from Noveon (AMP-acrylate / allyl methacrylate copolymer), FIXATE (polyacrylate-X), Ultrez 10 (Carbomer), CARBOPOL Ultrez (Acrylates / C10-30 Alkyl Acrylate Copolymer), AVALLTRE Series (acrylate copolymers), AVALURE series (polyurethane-2, polyurethane-4, PPG-17 / IPDI / DMPA copolymer); polyethylene glycol; water-soluble acrylic compounds; water-soluble polyesters; polyacrylamide; polyamine; polyquaternary amine; styrene maleic anhydride (SMA) resin; polyvinyl amine; from Covestro C 2000 (polyurethane solution in ethanol (INCI-Polyurethane-64)), eco E 1000 (water-based polyurethane), C 1010(waterborne polyurethane), C 1008(waterborne polyurethane), C 1001 (aqueous polyurethane); Inolex Lexfilm Sun (INCI-Polyester-7 (and) Neopentyl Glycol Diheptanoate), Inolex Lexfilm Sun Natural MB (INCI-Caprylyl Glycerin / Sebacic Acid Copolymer), Inolex WetFilm MB (INCI-Trimethylpentanediol / Adipic Acid / Glycerin Crosspolymer), Inolex Lexfilm Spray (INCI-Polyester-10 (and) Propylene Glycol Dibenzoate) and Inolex Lexorez 100 MB (INCI-Adipic Acid / Diethylene Glycol Crosspolymer) from Inolex; and other conventional polymers that are soluble in polar solvents or can be dissolved by neutralization with an appropriate base.

[0142] In one embodiment, the sunscreen formulation comprises, in addition to the polyvinyl alcohol described herein, at least one biodegradable polydextrose film-forming polymer based on starch esters.

[0143] In another embodiment, the sunscreen formulation comprises, in addition to the polyvinyl alcohol described herein, at least one biodegradable polyester film-forming polymer.

[0144] In another embodiment, the sunscreen formulation comprises, in addition to the polyvinyl alcohol described herein, at least one biodegradable diisostearoyl polyglyceryl-3 dimer dilinoleate film-forming polymer.

[0145] In a particularly preferred embodiment, the diisostearoyl polyglyceryl-3 dimer dimer linoleate film-forming polymer comprises diisostearoyl polyglyceryl-3 dimer linoleate and caprylic / capric triglyceride.

[0146] When the sunscreen formulation comprises other film-forming polymers in addition to the polyvinyl alcohol described herein, these other film-forming polymers may also be present in the sunscreen formulation in an amount of 0.1 to 10% by weight, based on the total weight of the formulation.

[0147] In a preferred embodiment, such further film-forming polymers are incorporated into the sunscreen formulations in an amount of 0.5 to 5% by weight, based on the total weight of the formulation.

[0148] In another preferred embodiment, the total amount of all other such film-forming polymers and the polyvinyl alcohol described herein is from 0.1 to 10 wt. %, based on the total weight of the formulation.

[0149] In an especially preferred embodiment, the total amount of all other such film-forming polymers and the polyvinyl alcohol described herein is from 0.5 to 5% by weight, based on the total weight of the formulation.

[0150] The disclosed sunscreen formulations may contain a variety of additional, optional ingredients, which are referred to herein as "cosmetic ingredients," but may also include ingredients commonly referred to as pharmaceutically active agents. The CTFA Cosmetic Ingredient Handbook, Seventh Edition, 1997, and Eighth Edition, 2000, the entire contents of which are incorporated herein by reference, describe a variety of cosmetic and pharmaceutical ingredients commonly used in skin care compositions, which ingredients are suitable for use in the compositions of the present disclosure. Examples of these functional classes disclosed in the reference include absorbents, abrasives, anti-caking agents, defoaming agents, antioxidants, binders, biological additives, buffers, fillers, chelating agents, chemical additives, colorants, cosmetic astringents, cosmetic antimicrobial agents, denaturants, pharmaceutical astringents, topical analgesics, film formers, fragrance components, humectants, sunscreens, pH adjusters, plasticizers, reducing agents, skin bleaching agents, skin conditioners (emollients, moisturizers, miscellaneous and occlusives), skin protectants, solvents, foam boosters, hydrotropes, solubilizers, suspending agents (non-surfactants), SPF boosters, water repellents and viscosity enhancers (aqueous and non-aqueous).

[0151] The compositions of the present disclosure can be applied to the skin as liquid applicators, but are most commonly applied as sprays. However, the compositions are not limited to those compositions that are applied to the skin primarily as sunscreens. Compositions also include those formulations in which the sunscreen active agent is a component of another topical composition. Some non-limiting examples are lipsticks, makeup, lip balms, eye shadows, hair dyes, and conditioners, or any application where sunscreen may be considered beneficial.

[0152] In one embodiment, where the disclosed formulations are to be used in applications where sun protection may be considered beneficial, the disclosed formulations provide a static sun protection factor ("static SPF"). Without limitation, the SPF may be greater than or less than 10, or greater than 20, or greater than 25, or greater than 30, or greater than 35, or greater than 40, or greater than 45, or greater than 50, or greater than 55, or greater than 60, or greater than 65, or greater than 70, or greater than 75, or greater than 80, or greater than 85, or even higher.

[0153] In one embodiment, where the disclosed formulations are to be used in applications where sun protection may be considered beneficial, the disclosed formulations provide a water resistant sun protection factor ("WR SPF"). Again, without limitation, the SPF may be greater than or less than 10, or greater than 20, or greater than 25, or greater than 30, or greater than 35, or greater than 40, or greater than 45, or greater than 50, or greater than 55, or greater than 60, or greater than 65, or greater than 70, or greater than 75, or even higher.

[0154] The present disclosure will now be described in more detail with reference to the following non-limiting examples.

[0155] Example

[0156] Embodiment 1:

[0157] A. Anhydrous Formulation Preparation

[0158] An anhydrous formulation was prepared to illustrate the spray product: an anhydrous concentrate was prepared in a 400 mL beaker by charging 63 grams of anhydrous ethanol SDA-40B into the beaker, adding 2 grams of polyvinyl alcohol derivative or control polymer under stirring and mixing for about 30 minutes until fully dispersed. 3 grams of avobenzone (Neo 357, Symrise), 13g homosalate (Neo HMS, Symrise), 5g ethylhexyl salicylate (Neo OS, Symrise), 9g Octocrylene (Neo An oil phase consisting of 5 g of benzoic acid C12-15 alkyl ester (Finsolv TN, Innospec) was added into a beaker and mixed for about 30 minutes, and the results were observed.

[0159] Table 1

[0160]

[0161] B. Solubility Results

[0162] The desired result is a clear, single-phase and complete solution, which indicates that the formulation is completely soluble. On the other hand, if the solution is turbid or contains precipitates, it indicates that the formulation is at least partially insoluble. Evaluations were performed immediately after mixing ("initial solubility") and after 24 hours ("24 hour solubility").

[0163] Table 2

[0164]

[0165] 1 Acrylic copolymer from Nouryon

[0166] 2,3 Polyvinyl alcohol from Kuraray

[0167] 4,5,6,7 Polyvinyl alcohol, from Nouryon

[0168] 8 We tested (1) Poval TM 5-74 (DH=72.5-74.5%); (2) Poval TM 4-88 (DH = 86.7-88.7); and (3) Poval TM 4-98 (DH = 98.0-98.8%), in each case the polymer was completely insoluble in absolute ethanol at 5 wt%, 2.5 wt% and 1 wt%.

[0169] The results showed a clear correlation between the degree of hydrolysis of the film-forming polymer and the solubility of the formulation in anhydrous ethanol.

[0170] In general, the solubility of any disclosed film-forming polymer in any particular solvent or solvent system can be determined in a straightforward manner analogous to this Example.

[0171] Embodiment 2:

[0172] The derivatives were prepared and tested similarly to Example 1.

[0173] The succinate esters are prepared by reacting a base polyvinyl alcohol polymer with succinic anhydride.

[0174] Caprolactone condensation products are prepared by reacting a base polyvinyl alcohol polymer with caprolactone.

[0175] The vinyl pivalate was prepared as described in Example 12 below.

[0176] The 2-ethylhexanoate was prepared as described in Example 11 below.

[0177] The vinyl laurate was prepared as described in Example 10 below.

[0178] Table 3

[0179] # Film-forming polymers Initial solubility 24 hours solubility 9 PVA LM-20 succinate (80:20) clarify clarify 10 PVA LM-20 succinate (70:30) clarify clarify 11 PVA LM-10HD succinate (80:20) clarify clarify 12 PVA LM-10HD succinate (70:30) clarify clarify 13 PVA LM 10HD + Caprolactone (80:20) clarify clarify 14 PVA LM 10HD + Caprolactone (90:10) clarify clarify 15 PVA LM-20+caprolactone (90:10) clarify clarify 16 PVA LM-20+caprolactone (80:20) clarify clarify 17 PVOH vinyl neopentanoate (93:7; DH 32%) clarify clarify 18 PVOH vinyl neopentanoate (93:7; DH 55%) clarify clarify 19 PVOH vinyl neopentanoate (93:7; DH 73%) clarify clarify 20 PVOH vinyl neopentanoate (93:7; DH 83%) clarify clarify 21 PVOH 2-ethylhexanoate (95:5; DH 19%) clarify clarify 22 PVOH 2-ethylhexanoate (95:5; DH 36%) ND ND 23 PVOH 2-ethylhexanoate (95:5; DH 52%) ND ND 24 PVOH 2-ethylhexanoate (95:5; DH 73%) clarify clarify 25 PVOH Vinyl Laurate (96:4; DH 35%) clarify clarify 26 PVOH vinyl laurate (96:4; DH 61%) clarify clarify 27 PVOH vinyl laurate (96:4; DH 80%) clarify clarify

[0180] ND = Not Determined

[0181] Embodiment 3:

[0182] Selected polymer samples (using the numbers in the table above) were prepared in ethanol solvent along with an oil phase and blended with the propellant according to the following procedure to understand the compatibility with the propellant.

[0183] Preparation procedure:

[0184] 1. Charge all of the ethanol in the formulation into the main mixing vessel.

[0185] 2. Start mixing by propeller agitation (adjust mixing speed until there is a vortex 2 / 3 of the way up the agitator shaft).

[0186] 3. Slowly add the polymer powder through the sifter to one side of the vortex. Allow the polymer to disperse completely.

[0187] 4. Slowly add the oil phase to the vortex and continue stirring until clear and homogeneous.

[0188] 5. Fill the concentrate into an aerosol container and add the propellant.

[0189] 6. Observe the charged aerosol for clarity, phases, and any precipitate that may have formed initially and over time.

[0190] In the following examples, the propellant is 30% isobutane or 30% and 40% dimethyl ether (DME) of the total formulation. When the propellant is 30% by weight of isobutane, the test formulation contains 1.4% by weight of polymer, 44.1% by weight of ethanol, 24.5% by weight of UV oil phase and 30% by weight of isobutane propellant. When the propellant is 30% by weight of DME, the test formulation contains 3% by weight of polymer, up to 1% by weight of aminomethyl propanol, 70% by weight of ethanol and 30% by weight of dimethyl ether propellant. When the propellant is 40% by weight of DME, the test formulation contains 3% by weight of polymer, up to 1% by weight of aminomethyl propanol, 60% by weight of ethanol and 40% by weight of dimethyl ether propellant.

[0191] The desired result is a clear, single-phase and complete solution, which indicates that the formulations are compatible. On the other hand, if the solution is cloudy or opaque or contains precipitates, it indicates that the formulations are at least partially incompatible.

[0192] Table 4

[0193]

[0194]

[0195] 1 Dimethyl ether (DME)

[0196] ND = Not Determined

[0197] The results indicate that the solubility of the base polymer in anhydrous ethanol does not guarantee compatibility with the propellant. None of the disclosed film-forming polymers have been demonstrated to be compatible with isobutane propellant. However, many of the disclosed film-forming polymers are compatible with 30% and 40% DME.

[0198] In general, the compatibility of any disclosed film-forming polymer with a particular propellant or solvent-propellant system can be determined in a straightforward manner analogous to this example.

[0199] Embodiment 4:

[0200] In order to demonstrate the effectiveness of the sunscreen formulation examples made with the polyvinyl alcohol of the present disclosure, or to demonstrate the lack of effectiveness of formulations made with control products, for each formulation made, a series of tests were conducted to quantify the so-called Sun Protection Factor (SPF) and to demonstrate their effectiveness in producing provably water resistant sunscreen formulations.

[0201] Because of the importance of SPF testing for labeling consumer sunscreen products, government agencies regulate the labeling of these products and require that products be tested by a panel of people using specific statistical criteria. (Static) SPF measures the time it takes for erythema to develop on skin protected by a sunscreen product compared to skin not protected by a sunscreen product on the same panel.

[0202] Water-Resistant (WR) SPF measurements are similarly made after a standard immersion of the skin in 40°C water.

[0203] For laboratory measurements of SPF and WR SPF, a range of in vitro measurements can be performed. Europe uses the Colipa test method. The US uses the FDA 21 CFR Section 201 and 320 tests. These measurements involve the use of a plastic film or substrate to simulate the roughness and other properties of human skin. In this case, the SPF measurement using the substrate can be made using a variety of instruments. We used a Labsphere UV-1000 spectrophotometer. We followed the manufacturer's instructions using the Vitro Skin TM(from Florida Suncare, Inc., formerly IMS Inc).

[0204] Apply 20 drops of 5 mg sunscreen concentrate on the film and spread the sunscreen concentrate carefully and evenly over 55.8 cm 2 The membrane area was then 2 mg / cm 2 Apply. Use an ultraviolet spectrophotometer to measure the absorbance (or transmittance) of UVA radiation (320-400 nm) and UVB radiation (290-320 nm). From these values, the in vitro SPF of the skin with and without the application of sunscreen product on the artificial skin can be measured.

[0205] Results are reported as in vitro SPF and in vitro WR SPF, where the former is also measured after a standard drying time and the latter is measured after immersing the same film in water at 40°C for 80 minutes. These in vitro measurements have been shown to correlate with in vivo data. Other data (such as UVA and UVB ratios) can also be determined and used to quantify the protection provided by the sunscreen formulation. Alternatively, for the Colipa Tech method, Helioplate HD6 embossed PMMA plates are from Helio Labs Inc. These PPMA plates have an RMS surface roughness of 6 microns and can be used without hydration. Due to the different depths of roughness, the same 2 mg / cm 2 After the dosed sunscreen lotion is applied and dried on the plate, a "peak" in surface roughness will be present where relatively little UV absorbing oil is present. Therefore, the absorbance and calculated SPF may be slightly reduced relative to in vivo and other in vitro measurement techniques. However, both in vitro substrates produce reproducible results and can be compared using appropriate correction factors.

[0206] Therefore, according to standard practice in the art, the absorption of UV light by plastic films coated with UV absorbing sunscreen formulations is used to simulate human skin and the absorption of UV light is measured with a spectrophotometer to provide a measurement of the Sun Protection Factor (SPF). SPF is simply the ratio of the original light to the light transmitted through the UV absorbing film. If 100% is reduced to 10%, the SPF is 10. If 100% is reduced to 1%, the SPF is 100. SPF 50 is equivalent to 2% of the UV rays penetrating the skin.

[0207] In each case, 20 drops of a solution containing 5 mg of the test polymer were applied to a surface area of ​​55.8 cm 2 The lens is then placed on a UV absorbing film and exposed to UV light in the 280 to 400nm range to provide what is known as a "static" SPF measurement.

[0208] In vitro water repellent SPF (WR SPF) measurements are made by placing the same film in a water bath heated to 40°C with gentle agitation. The sample is removed, gently dried under reproducible conditions, and the light transmittance is measured again, this time providing the WR SPF data.

[0209] Table 5

[0210]

[0211]

[0212] Embodiment 5:

[0213] Pair Comparison—Eight panelists used two different leave-on products and applied them to the outside of their forearms for a blind evaluation. Panelists had to choose one product applied to the outside of their forearms as being stronger than the other product in terms of various performance attributes. Performance data were aggregated and statistically analyzed.

[0214] Skin preparation:

[0215] Panelists will use the provided ethanol swab to clean the entire lateral forearm area and their assessment finger. Once the ethanol has completely evaporated, a circle approximately 1.50 inches in diameter will be drawn on the forearm as the assessment site and labeled alphabetically (A or B). Be careful to avoid the wrist and elbow area and leave enough space between samples to ensure that the samples do not collide with each other during application.

[0216] Evaluation of application by panelists:

[0217] 1. Provide evaluation ballots to group members to record their answers.

[0218] 2. Ensuring that the panelists are unaware of the identity of the samples, approximately 0.4 μL of each sample (A and B) should be applied to the center of the evaluation site using an electronic pipette.

[0219] 3. The panelist spreads a measured amount of product within the circle using gentle circular motions with the index or middle finger (at a rate of approximately 2 strokes per second).

[0220] 4. The following is a panelist's evaluation of the experimental sunscreen solution and the control sunscreen solution in the above sunscreen formulation ( 79; Acrylates / Octyl Acrylamide Copolymer, Nouryon) Properties evaluated when compared:

[0221] Spreadability: How easily a product moves across the skin (difficult / easy to drag / glide).

[0222] After 10 rubs, rate and select which product has the strongest following attributes:

[0223] Tackiness: The degree to which residual product adheres to fingers (non-sticky to very sticky).

[0224] Visually analyze the forearm test site to evaluate:

[0225] Luster: The amount or degree to which skin reflects light (none to a lot).

[0226] Immediate feeling after use: Use clean fingers to gently stroke skin (1-2 times) and evaluate:

[0227] Slipperiness: How easy it is to move a finger across the skin (difficult / easy to drag / slide);

[0228] Residue: The amount of product on the skin (none to a lot);

[0229] Oily feel: slippery, smooth, continuous feeling (i.e. baby oil);

[0230] Powdered: A very dry, thin, slippery coating (i.e. corn starch).

[0231] After the product had been absorbed into the skin for approximately 5 minutes, the tack was assessed again:

[0232] Tack 2: The degree to which residual product adheres to fingers (not sticky to very sticky).

[0233] At the end of the attribute evaluation, the panelist was asked to select the product he / she preferred, indicated by “overall preference.”

[0234] Data analysis / evaluation:

[0235] Samples exhibit this property less frequently: 0 to 1 of the 8 selected experimental samples show statistically significant differences from the reference at the 95% confidence level;

[0236] The samples showed no statistical difference compared with the standard: 2 to 6 out of 8 selected experimental samples showed statistically significant differences at the 95% confidence level;

[0237] The samples showed this performance more often: 7 to 8 out of 8 selected experimental samples showed statistically significant differences from the reference at the 95% confidence level.

[0238] Regarding spreadability, slip and preference, it is desirable to have more of these properties; regarding stickiness, gloss, residue and oiliness, it is desirable to have less of these properties.

[0239] Table 6

[0240]

[0241] Embodiment 6:

[0242] Several embodiments of the present disclosure have been tested by OECD Biodegradability Method 301 D, details of which are readily available. Testing was performed in both river water and activated sludge.

[0243] Table 7

[0244]

[0245] Table 8

[0246]

[0247] OECD 301D ratings include (1) “ultimately biodegradable”, which means a biodegradation rate of ≥ 60% within 60 days; (2) “readily biodegradable”, which means a biodegradation rate of > 60% within 28 days; (3) “inherently biodegradable”, which means a biodegradation rate of 20% to 60% within 28 days; and (4) “non-biodegradable”, which means a biodegradation rate of less than 20% within 28 days.

[0248] Example 7: Preparation of an intermediate copolymer with pendant acetate functional groups; this intermediate copolymer is a precursor to a PVOH copolymer esterified with lauric acid.

[0249] A four-necked 1 L round bottom flask was equipped with a mechanical stirrer; a Claisen adapter equipped with a temperature probe and a reflux condenser; a 500 mL addition funnel (non-pressure balanced type); and a 125 mL addition funnel (non-pressure balanced type). The flask was charged with 7.50 g of vinyl laurate, 67.5 g of vinyl acetate, 51.15 g of ethyl acetate, and 2.91 g of 98% tert-butyl peroxyoctanoate. The 500 mL addition funnel was charged with a mixture of 22.50 g of vinyl laurate and 202.50 g of vinyl acetate (monomer SA-1). The 125 mL addition funnel was charged with a mixture of 2.91 g of 98% tert-butyl peroxyoctanoate and 67.95 g of ethyl acetate (initiator SA-2).

[0250] The reaction mixture was refluxed using a hot water bath under stirring. After the reaction mixture refluxed for 5 minutes, the contents of monomer SA-1 were uniformly added to the reaction mixture over a period of 4 hours. When the addition of monomer SA-1 was complete, the feed hopper was rinsed (flushed into the reactor) with 4.61 g of ethyl acetate. After the reaction mixture refluxed for 1 hour, the contents of initiator SA-2 were uniformly added to the reaction over a period of 5 hours.

[0251] After the addition of initiator SA-2 was complete, the reaction was refluxed for another 2 hours (total reaction time was 8 hours). The reaction was then cooled to below reflux and 70.0 g of ethanol was added. After a uniform solution was obtained, the reaction was left overnight.

[0252] After standing overnight, the reaction was brought back to reflux and a solution of 0.90 g of tert-butyl peroxyoctanoate in 7.50 g of ethanol was added in one go. After the initiator was added in one go, the heating at reflux was continued for 2 hours. The reaction was then allowed to cool below reflux and 104.0 g of ethanol was added. The reaction was stirred until a uniform polymer solution was obtained and then allowed to cool. A clear, colorless, viscous polymer solution was obtained. Solids content (determined gravimetrically): 49.94%.

[0253] Examples 8 and 9: Preparation of intermediate copolymers with pendant acetate functional groups; the intermediate copolymers are precursors to PVOH copolymers esterified with 2-ethylhexanoic acid and pivalic acid, respectively.

[0254] Other intermediate copolymers were prepared using different hydrophobic esters of vinyl alcohol following the general procedure described in Example 7. The compositions of all intermediate copolymers estimated based on the feed ratio of the two monomers are summarized in Table 9 below.

[0255] Table 9

[0256]

[0257] Example 10: The intermediate copolymer of Example 7 was partially hydrolyzed to obtain a PVOH polymer esterified with lauric acid.

[0258] A four-necked 1L round bottom flask was equipped with a mechanical stirrer, a Claisen adapter, a septum and a stopper equipped with a temperature probe and a Barrett trap with a reflux condenser on top. 250.5g of the polymer solution prepared in Example 7 (125.0g, solid basis) and 146g of ethanol were added to the flask. The resulting mixture was stirred until a uniform solution was obtained, and then 2.25g of 98% sulfuric acid was added to the reaction mixture. A hot water bath was used to reflux the reaction vigorously, and a total of 40g of ethanol was distilled from the reaction through the Barrett trap. Heating was continued for 7 hours at a gentle reflux (no more ethanol was distilled). At a reaction time of 2 hours and 4.5 hours, about 65g of the reaction mixture was taken out, stirred with about 4.5g of Amberlyst A21 weakly basic ion exchange resin for about 1 hour, filtered to remove the ion exchange resin, and then dried on a baking tray in a forced air oven at 60°C to constant weight. A sample of the reaction mixture was treated in the same manner at the end of the reaction (7 hours). In this way, three partially hydrolyzed laurate-esterified PVOH polymers with different degrees of hydrolysis were obtained. Their compositions are summarized in Table 10.

[0259] Examples 11 and 12: The intermediate copolymers of Examples 8 and 9 were partially hydrolyzed to obtain PVOH polymers esterified with 2-ethylhexanoic acid and pivalic acid, respectively.

[0260] The precursor polymers in Examples 8 and 9 were partially hydrolyzed following the same general procedure described in Example 10. Their compositions are summarized in Table 10 below.

[0261] Table 10.

[0262]

[0263] *Composition: C- 13 NMR (DMSO-d6 solvent) measurement

[0264] Example 13: Polyvinyl alcohol-crotonic acid copolymer

[0265] Following the general procedure described in Example 7, a series of intermediate copolymers with carboxylic acids pendant on the backbone (precursors of PVOH copolymers modified with internal γ-lactones (cyclic esters)) were prepared by copolymerizing vinyl acetate and crotonic acid in varying relative amounts. 13 The compositions of these intermediate copolymers determined by NMR (DMSO-d6 solvent) are summarized in Table 11 below.

[0266] Table 11

[0267]

[0268] Following the same general procedure described in Example 10, the intermediate (precursor) copolymer was partially hydrolyzed. 13 The compositions determined by NMR (DMSO-d6 solvent) are summarized in the following Table 12. It should be noted that under the conditions used to partially hydrolyze the intermediate (precursor) copolymer, most of the carboxylic acid moieties pendant to the intermediate (precursor) copolymer spontaneously formed (cyclic) esters (internal γ-lactones) with the alcohol pendant to the nascent PVOH copolymer; in some cases, a small portion (<40%) of the carboxylic acid moieties pendant to the intermediate (precursor) copolymer did not form (cyclic) esters with the alcohol from the pendant to the nascent PVOH copolymer.

[0269] Table 12

[0270]

[0271] a Intermediate (precursor) polymer: 34

[0272] b Intermediate (precursor) polymer: 35

[0273] c Intermediate (precursor) polymer: 36

[0274] d Intermediate (precursor) polymer: 37.

[0275] Embodiment 14

[0276] Selected polymer samples having the compositions in the table below were prepared in ethanol solvent and blended with propellants according to the procedure of Example 3 to understand the compatibility with the propellants.

[0277] In the following examples, the propellant was 40% of the total formulation HPC 152A. In each case, the test formulation contained 3% polymer, 5% water, q.s. ethanol and 40% hydrofluorocarbon 152A propellant.

[0278] The desired result is a clear, single-phase and complete solution, which indicates that the formulations are compatible. On the other hand, if the solution is cloudy or opaque or contains precipitates, it indicates that the formulations are at least partially incompatible.

[0279] Table 13

[0280]

[0281] In all cases, the copolymers proved to be compatible with the formulations, resulting in very slightly turbid single-phase aerosols.

[0282] Although the present disclosure has been described in conjunction with the above specific embodiments, many substitutions, modifications and other variations thereof are apparent to those skilled in the art. All such substitutions, modifications and variations are intended to fall within the spirit and scope of the present disclosure.

Claims

1. A sunscreen formulation comprising: (a) volatile solvents; (b) at least one film-forming polymer comprising at least one of: (i) polyvinyl alcohol or (ii) a polyvinyl alcohol ester having, in addition to the proprietary acetate, further ester functional groups, and (i) and (ii) being soluble in a volatile solvent; and (c) at least one sunscreen active.

2. The sunscreen formulation according to claim 1, wherein the volatile solvent is an alcohol-based solvent system, wherein the alcohol-based solvent system comprises at least one C 1-6 Straight or branched chain alcohols.

3. The sunscreen formulation according to claim 2, wherein the alcohol-based solvent system comprises ethanol.

4. Sunscreen formulation according to any of the preceding claims, comprising 0 to 20% by weight of water.

5. The sunscreen formulation according to any one of the preceding claims, which is free of water.

6. The sunscreen formulation according to claim 5, comprising ethanol but not any other alcohol.

7. The sunscreen formulation according to any one of the preceding claims, wherein the at least one sunscreen active agent is selected from the group consisting of: p-aminobenzoic acid, avobenzone, cinoxate, dioxybenzone, homosalate, menthyl anthranilate, octyl salicylate, oxybenzone, padimate O, phenylbenzimidazole sulfonic acid, sulisobenzone, triethanolamine salicylate, titanium dioxide, zinc oxide, diethanolamine methoxycinnamate, digalloyl trioleate, ethyl dihydroxypropyl PABA, glyceryl aminobenzoate, 2-hydroxy-1,4-naphthoquinone containing dihydroxyacetone, red petrolatum, ethylhexyl triazone, dioctylbutyrylamino triazine Ketone, benzylmalonate polysiloxane, terephthalylidene dicamphor sulfonic acid, disodium phenyl dibenzimidazole tetrasulfonate, diethylamino hydroxybenzoyl hexyl benzoate, bis diethylamino hydroxybenzoyl benzoate, bis benzoxazolyl phenyl ethylhexyl imino triazine, drometrizole trisiloxane, methylene bis benzotriazolyl tetramethylbutylphenol, bis ethylhexyloxyphenol methoxyphenyl triazine, 4-methylbenzylidene camphor, homosalate, butyl methoxydibenzoylmethane, octocrylene, octyl salicylate, bemotriazine alcohol, isopentyl 4-methoxycinnamate, 3-benzophenone (BP3), 4-di Benzophenone (BP4), homosalate (HMS), 2-ethylhexyl salicylate (EHS), ethylhexyl dimethyl para-aminobenzoate (OD-PABA), 4-para-aminobenzoic acid (PABA), phenylbenzimidazole sulfonic acid (PMDSA), disodium phenyl dibenzimidazole tetrasulfonate (disodium phenyl bisbenzimidazole tetrasulfonate), ethylhexyl triazone (OT), diethylhexyl butyryl amino triazone (DBT), bis-ethylhexyloxyphenol methoxyphenyl triazine (EMT), drometrizole trisiloxane (DRT), methylene bis-benzotriazolyl tetramethylbutylphenol (MBP, Bis cotrizole), 4-tert-butyl-4'-methoxydibenzoylmethane (BM-DBM, avobenzone), ethylhexyl methoxycinnamate (OMC), isoamyl p-methoxycinnamate (IMC, amiloride), terephthalylidene dicamphor sulfonic acid (PDSA), 3-benzylidene camphor (3BC), benzylidene camphor sulfonic acid (BCSA), 4-methylbenzylidene camphor (4-MBC), polyacrylamidomethylbenzylidene camphor (PBC), camphor benzalkonium chloride methylsulfate (CBM), titanium dioxide, zinc oxide, iron oxide, zirconium oxide, cerium oxide and mixtures thereof.

8. The sunscreen formulation according to claim 7, wherein the at least one sunscreen active agent is selected from avobenzone, homosalate, octylsalicylate, octocrylene and oxybenzone.

9. The sunscreen formulation according to any one of the preceding claims, wherein the at least one film-forming polymer comprises polyvinyl alcohol having a degree of hydrolysis of from about 35% to about 58%.

10. The sunscreen formulation according to any one of claims 1 to 9, wherein the at least one film-forming polymer comprises an ester of polyvinyl alcohol.

11. The sunscreen formulation according to any one of claims 1 to 10, which is a sprayable sunscreen formulation.

12. The sunscreen formulation according to claim 11, further comprising one or more additives selected from film-forming polymers, plasticizers, UV absorbers, dyes, fragrances, preservatives, viscosity modifiers, vitamins, moisturizers and anti-itch ingredients.

13. The sunscreen formulation according to any one of the preceding claims, which is an aerosol formulation and further comprises a propellant.

14. The sunscreen formulation according to claim 13, wherein the propellant is dimethyl ether (DME).

15. The sunscreen formulation according to claim 14, wherein the propellant is 1,1-difluoroethane.

16. The sunscreen formulation of claim 13, comprising a dual valve bag device comprising an insert comprising the sunscreen formulation and a propellant surrounding the insert.

17. A method of protecting a user who is to be or has been exposed to sunlight from the damaging effects of exposure to sunlight, the method comprising applying to the skin of the user an effective amount of a sunscreen formulation according to any one of the preceding claims.

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