EP0516766A4

EP0516766A4 - Cosmetic lotion

Info

Publication number: EP0516766A4
Application number: EP19910912715
Authority: EP
Inventors: James Peters
Original assignee: DowBrands Inc
Current assignee: DowBrands Inc
Priority date: 1990-07-09
Filing date: 1991-07-08
Publication date: 1993-03-24
Also published as: EP0516766A1; WO1992000724A1

Abstract

A cosmetic lotion for the sustained suppression of oily shine on the face of a user without stickiness and without altering or detracting materially from a desired natural, non-shiny appearance of the skin.

Description

COSMETIC LOTION

This invention relates to skin care products, and particularly to such products in the form of lotions.

Persons with oily skin frequently develop an unsightly shiny appearance to their foreheads and faces. This shiny appearance has previously been suppressed by means of repeated washings and the use of makeups including talc or clay, walnut shell flour, silica or porous polymers which incorporate the oils secreted by the sebaceous glands of the skin into preexisting pore spaces or which trap the oils in a matrix of fine particles.

The capacity of such materials for these oils is limited, however, and makeup can become discolored over time as sebum continues to be excreted and the makeup's capacity exceeded. A non-shiny appearance of the skin can as a result only be expected to last normally for two to three hours between washings and the application of additional makeup. The length of time for which a satisfactory matte appearance can be maintained can, however, be much shorter, particularly in oilier areas such as one's forehead. The present invention utilizes sebum-imbibing polymers of the type described in United States Patents No. 4,489,058 and 4,619,826 to Lay et al in a lotion for the suppression of oily shine on the skin of a user. These polymers have a significantly greater capacity for suppressing a shiny appearance of the skin than the materials previously employed for this purpose.

In one aspect the lotion of the present invention can be described as forming a thin film on the

10 face of a user, which through the sebum-imbibing polymers contained therein will effectively suppress oily shine over a comparatively longer period of time than the two to three hours typically seen for m _e- conventional oil-control and oil-absorbing cosmetics, without at the same time materially altering or detracting from the natural, non-shiny appearance that is desired as by coloring the user's skin.

₀ For accomplishing the aforementioned shine- suppressing thin film, the lotion of the present invention comprises an amount of one or more of these sebum-imbibing, sebum-retaining polymers which is effective for suppressing oily shine, in combination 5 with an amount of one or more naturalizing agents which is effective for enabling the formation of a generally invisible shine-suppressing film of the one or more sebum-imbibing, sebum-retaining polymers on the face of a user. The term "naturalizing agent" has been coined 0 for broadly describing the class of materials which, when employed in combination with the one or more sebum- imbibing, sebum-retaining polymers in sufficient amounts, enable a lotion comprising such polymers to form the generally invisible shine-suppressing film. These materials can be discrete compounds or mixtures of compounds.

In a further aspect, the applied lotion will not feel sticky to the touch in the suppression of oily shine. Such stickiness is undesirable in terms of the user's comfort in wearing a film of the material on his or her face, the possible transfer of material to the user's clothing, bed linens, etc. with which the user's face may come into contact, the potential to attract dirt to the face of the user, and the embarrassment and awkwardness occasioned by another's coming into contact with a sticky substance on the face of the user and finding such contact offensive or disagreeable.

Preferred embodiments of the lotion of the present invention are effective both in the sustained suppression of oily shine on the face of a user and in remaining substantially non-sticky throughout the suppression of such oily shine, and further do not materially alter or detract from the natural, non-shiny appearance that is desired as by coloring the user's skin.

I. Components of the Lotion - Type

As to the sustained suppression of oily shine, an effective lotion will be such that a trained dermatologist in a double blind test of the lotion against an untreated portion of the forehead of an oily- skinned user would perceive the treated portion of the user's forehead to be less shiny than the untreated portion. It is understood, of course, that where the comparison is made after washing the forehead area with soap and water, this difference in the shininess of the portions of one's forehead to which lotion has been applied (the treated portion) or has not been applied (the untreated portion) may not appear until a sufficient time has elapsed to replace some of the sebum removed by the washing.

An effective suppression of oily shine can also be considered as having occurred where a glass plate coated with the lotion of the present invention, and to which an excess of sebum or an apt sebum substitute such as olive oil has been applied, realizes at least a 50 percent reduction in reflectance after six hours compared to a glass plate coated with the same lotion absent the sebum-imbibing polymers and to which the same amount of sebum or the sebum substitute has been applied. Where these subjective and objective measures provide conflicting indications of the ability of a lotion to effectively suppress oily shine on the face of a user, the former subjective measure is considered controlling.

A sustained suppression of oily shine corresponds to the maintenance of a perceptible difference in the shininess of the treated and untreated portions of a user's forehead for a period of at least 3 hours after application of the lotion thereto, although preferably the difference is perceptible for a period of at least 6 hours and most preferably at least 8 hours after application. The number of hours of shine suppression which can be expected will, however, vary depending on the particular circumstances of the lotion's use such as the user, the amount applied and the area to which this amount is applied. A. One or More Sebum-Imbibing Polymers

1. Useful Sebum-Imbibing Polymers

The sebum-imbibing, sebum-retaining polymers _c which are useful in the present invention are those materials which possess a solubility parameter approaching that of sebum and which would therefore be generally soluble in sebum when applied to the face of a user, but which when cross-linked are made insoluble in 10 the sebum. Included in this class of materials are the homopolymers of aliphatic diolefins (i.e., alkadienes) or copolymers having polymerized therein two or three or more monomer units selected from the group consisting of alkenyl aromatic compounds, alkyl esters derived from an

15 aliphatic alcohol and acrylic or methacrylic acid, vinyl esters of aliphatic carboxylic acids, and aliphatic diolefins.

Also useful are polymers formed from at least 0 four monomer units selected from the group consisting of alkenyl aromatic compounds, alkyl esters derived from an aliphatic alcohol and acrylic or methacrylic acid, vinyl esters of aliphatic carboxylic acids, and aliphatic c diolefins. Of these sebum-imbibing, sebum-retaining polymers, preferred polymers are formed from at least four monomer units selected from the group consisting of styrene, styrene ring-substituted with a straight or branched chain alkyl moiety of from 1 to 12 carbon 0 atoms, an alkyl ester derived from an alcohol containing from 8 to 20 carbon atoms and acrylic ormethacrylic acid, a vinyl ester of an aliphatic carboxylic acid containing from 8 to 20 carbon atoms, and an aliphatic diolefin of from 4 to 6 carbon atoms. Representative examples of polymers comprised of at least four monomer units include, for example, a polymer having polymerized therein tert-butylstyrene, 2-ethylhexyl acrylate, lauryl methacrylate and vinyl toluene, or a polymer having polymerized therein styrene, lauryl methacrylate, isobornyl methacrylate, vinyl stearate and lauryl acrylate.

The alkenyl aromatic compounds which may be utilized in the preparation of the polymers useful

10 herein contain a straight or branched chain alkenyl residue of from 2 to 10 carbon atoms and may optionally be ring-substituted with halogen or a straight or branched chain alkyl moiety of from 1 to 20 carbon

-.,- atoms. Such compounds include, for example, various halostyrenes such as 2-chlorostyrene, 3-fl orostyrene, 4-fluorostyrene and the like, vinyl naphthalenes, alkylbenzene, 2-phenyl-2-butene, styrene and various substituted styrenes such as alkylstyrenes. Such 0 alkylstyrenes include, for example: n-alkylstyrenes such as methylstyrene or vinyl toluene, n-butylstyrene, n- amylstyrene, n-octylstyrene, n-octadecylstyrene,and the like; isoalkylstyrenes such as isobutylstyrene, isohexylstyrene, isododecylstyrene and the like; 5 sec-alkylstyrenes such as sec-butylstyrene, sec-hexylstyrene, sec-octylstyrene and the like; and tertiary-alkylstyrenes such as tert- butylstyrene,tert-amylstyrene, tert-octylstyrene, tert- 0 eicosylstyrene and the like.

The alkyl esters derived from an aliphatic alcohol and acrylic or methacrylic acid are acrylate or methacrylate esters derived from an alcohol moiety containing from 1 to 20 carbon atoms. Such esters include, for example, butyl methacrylate, butyl acrylate, hexyl acrylate, isobornyl methacrylate, cetyl methacrylate, eicosyl acrylate, the mixed ester cetyl- eicosyl methacrylate, lauryl methacrylate, stearyl methacrylate, isobornyl acrylate, and lauryl acrylate.

The vinyl esters of aliphatic carboxylic acids useful for the sebum-imbibing polymers of the lotion of the present invention are esters prepared from carboxylic acids containing from 2 to 20 carbon atoms such as vinyl acetate, vinyl butyrate, vinyl stearate, vinyl 2-ethylhexoate and the like.

The aliphatic diolefins useful as monomer units in the sebum-imbibing polymers of the lotion are alkadienes containing from 4 to 12 carbon atoms such as butadiene, pentadiene, 2-methyl-1 ,3-butadiene and the like.

Of the alkenyl aromatic compounds previously described, those which are preferred for use as monomer units are styrene and ring-substituted styrene wherein the substituent is a straight- or branched-chain alkyl moiety of from one to twelve carbon atoms (alternatively referred to as an alkylstyrene) such as vinyl toluene, n-hexylstyrene, sec-octylstyrene, tert-butylstyrene, n- dodecylstyrene and the like.

Relative to the alkyl esters derived from a C1-C20 alcohol and acrylic or methacrylic acid, those which are preferred as constituent monomer units are acrylate or methacrylate esters derived from an alcohol moiety containing from 8 to 20 carbon atoms, and may be a linear fatty alcohol residue such as cetyl, lauryl, stearyl, or eicosyl, or a secondary alcohol residue. The vinyl esters of aliphatic carboxylic acids preferred as monomer units are those wherein the aliphatic carboxylic acid contains from 8 to 20 carbon atoms such as vinyl stearate. Of the aliphatic diolefins, those diolefins containing from 4 to 6 carbon atoms are preferred.

2. Preferred Sebum-Imbibing Polymers

The one or more sebum-imbibing polymers used in the lotion are preferably able to imbibe at least a volume of sebum on the face of a user equal to one-half the volume of such polymers in the lotion, and most preferably at least a volume equal to the volume of such polymers. Polymers with these capacities for sebum imbibition can result from the combination of units of styrene or alkylstyrene with one or two or three or more comonomers selected from the group consisting of (a) an alkyl ester of a C1-C20 alcohol (especially a C8 to C20 alcohol) and acrylic or methacrylic acid; (b) a vinyl ester of a C8-C20 carboxylic acid; or (c) an aliphatic diolefin of from 4 to 6 carbon atoms. The alkylstyrene can be, for example, vinyl toluene or preferably a tertiary-alkylstyrene such as 4-tert-butylstyrene, 4- tert-amylstyrene, 3,5-ditert-butylstyrene, 4-tert- hexylstyrene, 4-tert-octylstyrene and the like. The alkyl ester monomer preferably includes one or both of a methacrylate or acrylate ester of one or more C8-C20 fatty alcohols, or a C10 to C20 fatty alcohol methacrylate or acrylate as essentially the sole comonomer. The vinyl ester may be an ester of a Cβ to C20 carboxylic acid such as vinyl stearate, vinyl palmitate, vinyl laurate and the like. The aliphatic diolefin is preferably butadiene. The polymers from these preferred combinations may contain from 5 to 95 percent styrene or alkylstyrene monomer by weight. Preferably, the polymer may contain from 30 to 60 to 85 to 90 percent by weight of styrene or alkylstyrene.

Other preferred polymers are prepared from alkyl ester monomers derived from a C8 to C20 alcohol and one or both of acrylic or methacrylic acid, or from an alkyl ester monomer derived from a C8 to C20 alcohol and acrylic or methacrylic acid as a comonomer with a vinyl ester of an aliphatic carboxylic acid containing from 8 to 20 carbon atoms, wherein the latter polymer contains from 20 to 70 percent by weight of the vinyl ester. Also preferred are homopolymers of aliphatic diolefins containing from 4 to 6 carbon atoms, such as polybutadiene.

Of the preferred polymers, those which are particularly preferred are: polymers of styrene and lauryl methacrylate; vinyl toluene and lauryl methacrylate; styrene and butadiene; polymers of tert-butylstyrene with lauryl methacrylate, stearyl methacrylate or vinyl stearate; terpolymers of tert-butylstyrene, 2-ethylhexylacrylate and lauryl methacrylate; terpolymers of tert-butylstyrene, 2-ethylhexylacrylate and stearyl methacrylate; polymers of isobornyl methacrylate and lauryl methacrylate; polymers of vinyl stearate and lauryl methacrylate or isobornyl methacrylate; polymers of tert-butylstyrene, 2-ethylhexylacrylate, lauryl methacrylate and vinyl toluene or stearyl methacrylate; and a homopolymer of butadiene. Most particularly preferred are the copolymers of lauryl methacrylate and isobornyl methacrylate, and most preferably the one or more sebum-imbibing, sebum- -retaining polymers in the lotion consist substantially entirely of a copolymer of lauryl methacrylate and isobornyl methacrylate. The copolymer is preferably from 40 to 60 parts by weight of isobornyl methacrylate per hundred parts by combined weight of the isobornyl methacrylate and lauryl methacrylate monomers, with from 60 to 40 parts by weight of lauryl methacrylate. More preferably, the monomer ratio by weight is from 50 to 60 parts of isobornyl methacrylate, to from 50 parts to 40 parts of lauryl methacrylate. Most preferably, the ratio by weight of the isobornyl methacrylate to lauryl methacrylate monomer units in the copolymer is 56 parts isobornyl methacrylate to 44 parts of lauryl methacrylate.

3. Crosslinked Polymers to Prevent Stickiness

The one or more sebum-imbibing, sebum-retaining polymers are in one aspect of the invention cross-linked to an extent whereby the film of the lotion formed on the user's face is substantially nonsticky throughout the suppression of oily shine.

Each of the polymers is cross-linked sufficiently so as to swell in sebum rather than dissolve in sebum; the additional degree of cross- linking in the polymers which is necessary for achieving the desired substantially nonsticky character is preferably conventionally accomplished by the addition to the polymerization recipes of one or more, or all of the sebum-imbibing polymer(s) of polyethylenically unsaturated cross-linking agents. Such polyethylenically unsaturated cross-linking agents include, for example, divinylbenzene, diethylene glycol dimethacrylate, diisopropenylbenzene, diisopropenyldiphenyl, diallyl maleate, diallyl phthalate, allyl acrylates, allyl methacrylates, allyl fumarates, allyl itaconates, alkyl resin types, butadiene or isoprene polymers, cyclooctadiene, methylene norbornylenes, divinyl phthalates, vinylisopropenylbenzene, and divinylbiphenyl compounds. Other di- or poly-functional compounds known to be of use as cross-linking agents in polymeric vinyl-addition compositions can also be used if desired.

While the level of cross-linking agent is generally reciprocally related to both the rate and capacity for imbibition of sebum by the polymers described herein, with the selection of a suitable polymer and above a certain level of cross-linking agent a substantial absence of stickiness in the applied lotions of the present invention can be achieved without an accompanying significant loss in the capacity to suppress oily shine. This substantial absence of stickiness is highly desirable.

At the same time, however, it will also be desirable to employ no more of the cross-linking agent(s) than necessary to achieve a non-sticky character, since additional cross-linking will generally diminish the ability of the lotion to suppress oily shine quickly and fully without an offsetting gain in terms of the lotion's non-stickiness on the user's face.

The amount of cross-linking which will just achieve the desired nonstickiness in the lotion as applied to the face of a user will be different for different lotion compositions, but can be established through routine experimentation with the guidance and examples provided herein.

The most preferred copolymer of lauryl methacrylate and .isobornyl methacrylate monomer units is cross-linked with at least 0.5 percent by weight based on the polymer of divinylbenzene to avoid stickiness in an "imbibed" condition. Preferably, 0.5 percent by weight of divinylbenzene is employed.

4. Form and Manufacture of Polymers

The particle size of the sebum-imbibing polymers used herein can vary based on considerations such as the desired rate of imbibition, the particular composition of a lotion and the like. In general, however, the particles may be from 100 Angstrom units to 2 millimeters wide at their smallest diameter. These small particles can be made by a variety of known methods such as by grinding, milling, cutting or comminuting extruded strands of polymer, or by emulsion or suspension polymerization techniques. Preferably, the particles are generally spherical particles with diameters of from 1 to 500 microns which are made by a known suspension polymerization technique.

In this suspension polymerization technique, the material to be reacted to form a given sebum- -imbibing, sebum-retaining polymer (the reaction mixture) is assembled by mixing the monomers and the cross-linking agent for a polymer in the proportions desired in the polymer (the monomer mixture). A polymerization initiator such as potassium persulfate or tert-butyl peroctoate is added either to the monomer mixture or to the aqueous portion of the polymeric microsuspension (consisting of water containing an emulsifying agent or suspending agent), depending on the initiator used and its relative solubility in the monomer mixture versus the aqueous portion with which the monomer mixture is to be combined.

The monomer mixture and aqueous portion are then mixed with stirring so that the particle size in the monomer mixture is reduced to the size desired for the polymerization and the monomer mixture is well- -dispersed in the aqueous base, with the monomer mixture comprising from 20 to 60 percent by weight of the combined reaction mixture. The resulting polymer can be recovered by passing the suspension through a screen.

B. Naturalizing Agents

The lotion of the present invention, while effective to suppress oily shine without stickiness, does so without materially altering or detracting from the natural, non-shiny appearance sought for the user's face.

Whereas a simple microsuspension of the one or more sebum-imbibing polymers in water would form a whitish film when applied to the user's face, by the addition of an effective overall amount of one or more naturalizing agents the composition forms a generally invisible shine-suppressing film.

Preferred naturalizing agents include propylene glycol, lecithin and a mixture of cetyl and stearyl alcohol, with the mixture of cetyl and stearyl alcohols - 14-

preferably being employed as a gelled dispersion in a dilute aqueous surfactant solution.

The materials useful herein as naturalizing agents appear to fall into two categories or to work by two mechanisms, one of which is not completely understood. A naturalizing agent may work by either mechanism or by a combination of the two, and combinations of naturalizing agents may similarly work by one mechanism exclusively or by a combination of the 0 mechanisms. The present invention is not intended to be limited in any way by the postulation of these mechanisms; the mechanisms and the preferred naturalizing agents exemplified below are intended only _t- to suggest candidates for further evaluation.

By the first mechanism, the naturalizing agent reduces light scattering by the sebum-imbibing polymers by having a refractive index which is between the _Q refractive index or indices of the one or more sebum- -imbibing polymers and that of the surrounding air. Whereas in the absence of the naturalizing agent a number of small, discrete imbibing polymer particles are deposited on the face, it is thought that with the 5 naturalizing agent a smooth film of substantially uniform refractive index is created, with the naturalizing agent filling the spaces around and between polymer particles. Propylene glycol, for example, is believed to perform as a naturalizing agent by this 0 mechanism. Of the class of materials capable of functioning as naturalizing agents in this fashion propylene glycol is particularly preferred for its lubricity. In the second postulated mechanism, not fully understood, the naturalizing agent plasticizes the polymers so that the polymers are deformable, allowing a reduction in the air-polymer interfacial area and thus reduced light scattering.

The plasticization of the one or more sebum- imbibing, sebum-retaining polymers has an additional beneficial effect also, in that the capacity for imbibition over a normal period of wearing the lotion and the rate of imbibition by the lotion are increased compared to a simple microsuspension of the polymers in water. This effect is observed for the cetyl/stearyl alcohol dispersion, which is believed to operate as a naturalizing agent primarily by a plasticization mechanism. Lecithin is also believed to have a plasticizing effect on the sebum-imbibing polymers of the lotion.

Naturalizing agents or combinations of naturalizing agents which include one or more plasticizers or which operate at least in part by a plasticization mechanism are because of this added benefit generally preferred over agents or combinations of agents which operate solely as gap-fillers with a suitable refractive index.

The combination of certain sebum-imbibing polymers and naturalizing agents which have a plasticizing effect on the sebum-imbibing polymers of the present lotion can, however, lead to problems with the stability of the lotion because polymers of a certain glass transition temperature and lower can be softened to the point where the beads of the polymers begin to stick together in the lotion. Polymers with lower glass transition temperatures also generally imbibe more sebum faster than sebum-imbibing polymers with relatively higher glass transition temperatures, though.

Consequently, where a naturalizing agent like the cetyl/stearyl alcohol mixture or lecithin is to be used, the sebum-imbibing polymer or polymers should be selected from among those specified above to have a glass transition temperature just high enough to give the lotion acceptable stability characteristics.

The cetyl and stearyl alcohol mixture enables the formation of the invisible shine-suppressing film of the lotion with an acceptable stability, for example, when employed in a lotion with an IBMA/LMA/0.5 percent DVB cross-linked copolymer which is comprised of equal parts by weight of the IBMA and LMA monomers and which has a glass transition temperature of 38°C. Better stability can be achieved with an IBMA/LMA/0.5 percent DVB copolymer that is richer in the IBMA monomer and which thus has a higher glass transition temperature, for example the most preferred 56/44/0.5 copolymer (glass transition temperature of 48°C).

C. Other Materials and General Considerations Regarding Materials Selection

The lotion of the present invention can contain conventional cosmetic-type materials or ingredients in addition to the sebum-imbibing polymer(s) and naturalizing agent(s), such as physiologically beneficial ingredients, adjuvants, perfumes, thickeners, emollients and preservatives. The materials which comprise the lotion with the one or more sebum-imbibing polymers and diluent

(e.g., the naturalizing agent(s) and other possible materials as described in the preceding paragraph) are in any event preferably selected so that the lotion is substantially free of such other materials which:

(A) have a solubility parameter δ of in the range of from 7 to 11 (cal/cm3)ι/2; ₀r

(B) otherwise interfere with the polymers' imbibition of sebum so that the lotion containing the polymers imbibes less than one-half the polymers' volume in sebum; or

(C) result in an unwanted degree of stickiness on the skin of a user.

Materials having solubility parameters in the range of from 7 to 11 ( may be imbibed by the polymers in the lotion, and thereby reduce the capacity of the lotion to imbibe sebum. Imbibition of these materials can also result in agglomeration and stability problems with the polymer particles or beads in the lotion.

Still other materials may not have a solubility parameter in this range, but may interfere with the imbibing function of the sebum-imbibing polymers, for example, by coating the polymer beads to an extent whereby a physical barrier to the sebum forms around a bead. An example of a material believed to present such difficulties is glycerine.

If the use of a material with a solubility parameter in the range of from 7 to 11 (cal/cm3)ι/2 is contemplated, tests will preferably be conducted to assess the impact of such a material on the efficacy and stability of a lotion containing the material.

II. Components of the Lotion - Proportions

In a most preferred embodiment of the lotion of the present invention, the one or more sebum-imbibing, sebum-retaining polymers are able to imbibe at least a volume of sebum on the face of a user equal to the volume of such polymers, and comprise from 1 to 40 percent by weight of the lotion.

Where the lotion contains for a sebum-imbibing polymeric portion only a cross-linked copolymer of from 40 to 60 parts by weight of isobornyl methacrylate (IBMA) and from 60 to 40 parts by weight of lauryl methacrylate (LMA) , cross-linked with 0.5 percent by weight of a crosslinking agent such as divinylbenzene (DVB), the sebum-imbibing polymeric portion or cross- linked IBMA/LMA copolymer will preferably comprise from 5 to 20 percent by weight of the lotion. Most preferably, the cross-linked IBMA/LMA copolymer will comprise from 8 to 16 percent by weight of the lotion.

In the embodiments employing the cross-linked IBMA/LMA copolymer at from 8 to 16 percent by weight, the one or more naturalizing agents will as noted previously preferably be propylene glycol, lecithin, or a cetyl/stearyl alcohol mixture. When propylene glycol is used as the naturalizing agent individually, it will comprise at least 1 percent by weight of the lotion, preferably from 1 to 10 percent by weight of the lotion. When lecithin is used as the sole naturalizing agent, it will comprise at least 0.5 percent by weight of the lotion up to 10 percent by weight of the lotion. The cetyl/stearyl alcohol mixture when used individually will be used in amounts of 0.3 percent by weight of the lotion, and preferably will comprise from 0.6 to 6 percent by weight of the lotion.

Other materials such as the perfumes, adjuvants, etc. will preferably comprise no more than 25 percent and most preferably less than 10 percent by weight of the lotion, with the remainder being water or a similar diluent.

Examples

The present invention is more fully illustrated by the following Examples:

Example 1

In this example the sebum-imbibing capacity of polymers as a function of cross-linking was investigated. A series of cross-linked copolymers of 50 parts by weight isobornyl methacrylate (IBMA) (based on combined monomer, i.e., IBMA and LMA, weight) and 50 parts by weight of lauryl methacrylate (LMA) were prepared by a suspension polymerization technique described above, with different levels of the cross- linking agent divinylbenzene (DVB) being employed.

As an example of the polymerization of a 50:50 copolymer of IBMA and LMA with 1.000 percent by weight of the monomer mixture (i.e., the IBMA, LMA, and DVB) of DVB, a monomer mixture was prepared including 1000.0 grams of IBMA, 1000.0 grams of LMA and 35.46 grams of a DVB solution (56.4 percent) in ethylvinylbenzene, with 3.97 grams of t-butylperoctoate added as an initiator. The monomer mixture was then combined with an aqueous portion for the polymeric microsuspension which contained 2356 grams of filtered, deionized water and 48.0 grams of a hydroxypropyl- methylcellulose, by mixing the monomer mixture and the aqueous portion in an Eppenbach mixer at 3000 rpm for 3 minutes and then at 5000 rpm for 15 minutes. The combined aqueous phase and monomer mixture were then polymerized in a round bottom flask at 75°C overnight.

10 After cooling, the microsuspension was filtered through a 200 mesh stainless steel screen.

In order to test the capacity of a given polymer to imbibe sebum, a bead of the polymer with an

-_jπ initial bead diameter of 150 microns was placed in a microscope well slide. The bead was covered with olive oil (as a model for sebum or sebum "substitute") and bead diameter measurements were taken microscopically over a period of time, until such time as an equilibrium 0 was reached and the bead stopped swelling. The temperature throughout was maintained at 37°C. The bead diameter measurements were used to calculate the change in volume of the bead at equilibrium and to thus determine the volume of oil imbibed. The results of the 5 testing are shown in Table 1 below.

0 10

15

These tests show that incremental increases in cross-linking yield progressively smaller decreases in sebum imbibition capacity.

20

Tests were also conducted of the rate of imbibition by the same polymers as a function of cross- linking. In these tests, 1 gram of polymer beads was placed in a graduated cylinder, and 20 grams of olive " oil were added. Measurements of the height of the beads in the graduated cylinder were taken over time as the beads swelled, the temperature again being held at 37°C throughout the testing. These results are reported at Table 2, wherein the assumptions have been made that the

30 beads are of substantially the same size from polymer to polymer (confirmed visually), and are of approximately the same density (all heavier than olive oil) so that the same number of beads was used of each polymer. Table 2 - Effect of DVB Level on Swelling Rate of Beads of 50/50 IBMA/LMA Copolymer (height in mm)

I

K) t

I

The data of Table 2 indicate that incremental increases in cross-linking also translate into progressively smaller decreases in the rate of imbibition of a polymer, and suggest that uncrosslinked and very lightly cross-linked polymers will generally t_ imbibe more sebum at a faster rate than more highly cross-linked polymers.

Example 2

10 This example illustrates the effect of the cetyl/stearyl alcohol mixture as a naturalizing agent in a lotion of the present invention, both in terms of the lotion's capacity for imbibition of olive oil as a sebum substitute/model and in terms of reduced reflectance

15 from a surface due to oil thereon that has not been imbibed by the lotion.

For this example a gelled dispersion of cetyl and stearyl alcohols was prepared by dissolving

20 0.60 grams of sodium dodecylsulfate in 500 grams of water, and stirring in 5.0 grams of cetyl alcohol and 1.25 grams of stearyl alcohol with heating (8θ°C) until the alcohols dissolved. The mixture was cooled and 2 became a gel.

To 10.00 grams of this gel was added 4.00 grams of a microsuspension (45.3 percent solids) of beads of a crosslinked copolymer having 56 parts by weight of IBMA

30 and 44 parts of LMA, with 0.05 percent by weight of DVB, in water containing a suspending agent. The lotion formed in this fashion was then placed on a shaker and mixed overnight.

This lotion, and a control lotion formed from the same polymer but without the naturalizing agent added, were then applied in 5-mil-thick coatings on glass plates and allowed to air dry. Olive oil was applied in varying amounts to each glass plate and the change in the reflectance of the coated plate determined over time, along with the amount of oil imbibed in that time. The latter measurement was taken by blotting excess oil from the plate with a tissue and thereafter weighing the plate, comparing the weight of the plate after imbibition with the weight of the plate before application of the olive oil.

The results of the measurements, reported in Table 3 below, show that the lotion containing the cetyl alcohol/stearyl alcohol naturalizing agent was able to imbibe greater amounts of the olive oil than the control lotion over the same period and exhibited reduced reflectance compared to the control as a result. Whereas the control lotion reached its capacity for imbibing the oil, the lotion comprising the naturalizing agent could have been expected to imbibe still more of the olive oil. Each of the slides was sticky after imbibing the oil, however.

Table - Effect of Alcohol Mixture

This example illustrates the reduction of the 0 stickiness of a film of the lotion of the present invention after imbibition of an oil such as sebum or an apt sebum substitute/model such as olive oil.

Polymers were prepared by a suspension 5 polymerization method with the same 56:44 monomer ratio between the IBMA and LMA monomers as in Example 2, and with divinylbenzene levels of about 0.1 percent, 0.2 percent, 0.4 percent, 0.5 percent and 1 percent by weight of the monomer mixture. Polymers were also made in a 40:60 monomer ratio with divinylbenzene levels of 0.4 percent and 0.5 percent by weight of the monomer mixture.

Lotions were then made from each of these polymers by the method of Example 2, with 4.00 grams of a 45 percent solids microsuspension of each polymer being combined with 10.00 grams of one of two different gelled cetyl/stearyl alcohol dispersions. One of the two dispersions, termed dispersion "A" hereafter, duplicated the gelled cetyl/stearyl alcohol dispersion of Example 2. The other of the two dispersions, called dispersion "B" hereafter, was made in the same fashion as dispersion A and the dispersion of Example 2, but contained 10.0 grams of cetyl alcohol instead of 5.0 grams and 2.50 grams of stearyl alcohol instead of the 1.25 grams employed in dispersion A.

Each of the lotions thus formed were applied in 5-mil-thick coatings on pre-weighed glass plates and allowed to air dry. 0.06000 Grams of olive oil were applied in 0.01 gram increments to each glass plate, after which the plates were weighed again.

After allowing the oil to be imbibed and an equilibrium to be reached over a period of 6 hours, excess oil was blotted from each plate with a tissue and the plate -weighed again to determine how much oil had been imbibed per gram of coating. Using the coating weight and the weight percentage of polymer beads in the dried coating, the average amount of oil imbibed per bead was then determined. This average amount of imbibed oil was taken as essentially equivalent to the change in the volume of the bead from Vo to the equilibrium volume V, discounting the differences in the densities of the imbibed oil and the polymer beads, for comparison to the V/Vo ratios actually observed in Example 1.

The stickiness of each plate was observed at this time, as well as the following morning. In each instance, the plates retained the character for stickiness observed after the initial 6 hour period. The measurements and observations relating to the various polymer coatings are shown in Table 4.

The lotions with higher DVB levels (0.4 to 1 percent) showed good imbibition of the oil with low stickiness.

Example 4

In this example, microsuspensions of two 56/44

IBMA/LMA copolymers having different degrees of cross- linking were combined in various proportions with a gelled dispersion of cetyl and stearyl alcohols to form a lotion in the manner of previous Examples 2 and 3.

These lotions were coated on glass plates, the coatings were allowed to air dry, and olive oil was applied and imbibed by the coatings. After 6 hours, the excess oil was wiped away and the plates tested for tackiness. The results are shown in Table 5 below.

Table 5

Average Oil Percent

. . Dispersion « ^*7Λ^βΛ,_«- Imbibed Oil Wt./ System IBMA/CMA/DVB ^Am°"^nt Amt > ^C™"Jⁱⁿ {^ne Out of Coating V/Vo Comment

^(B) (g) ^ABp^ee"rc'eJn ϊt ' 0 0..0066550000 Wt. *" Grams Coating

10 0.6 0.06505 1.009 93.51 2.079 Slightl Sticky

12 0.47 0.05232 1.768 90.05 2.963 Slightl Sticky

13 0.36 0.04252 1.820 89.31 3.038 Sticky

13.5 0.29 0.03450 1.653 85.88 2.925 Sticky

(a) Composed per dispersion "B" of Example 3.

Table 5 suggests the degree of cross-linking required for a substantial absence of stickiness in the lotions of the present invention can be achieved through a single cross-linked polymer as in Example 3, or by a combination of polymers of different degrees of cross- linking. Thus, lotions formed from combinations of polymers having an average cross-linking density of 0.36 percent or less were sticky to the touch, whereas lotions prepared from polymers having a higher average cross-linking density (0.47 and greater) were only slightly sticky.

Example 5

A double-blind randomized clinical evaluation of the lotion was conducted on the foreheads of 19 subjects determined by a Sebutape™ indicator (CuDerm Corporation) to have oilier-than-normal skin (ratings of 3 or higher on a scale of 0-6), wherein 0.09 grams of the inventive lotion of Example 2 was applied to half of each person's forehead (the treated side) as an essentially invisible film and the other half of the person's forehead was left untreated (the untreated side) .

Sebumeter readings were taken after arrival of the subject to the test area, immediately after washing with soap and water, and at intervals after application of the lotion, on the treated and untreated portions of each person's forehead. At the same time as the sebumeter readings were taken, subjective dermatological ratings were recorded based on visual observation by a trained dermatologist according to a four-point rating scale: 0= No evidence of oil;

1= Small beads of oil at pilosebaceous glands;

2= Skin slightly shiny; and

3= Skin very shiny.

The average sebumeter readings for the treated and untreated portions of a subject's forehead are reported as a function of time in Table 6.

In similar fashion, the corresponding average dermatological ratings are provided in Table 7.

Table 7 - Dermatolo ical Ratin s

Evaluating the data shown in Tables 6 and 7, from Table 6 it can be seen that the treated side had a lower average sebumeter reading after 6 hours than did the untreated side after 2 hours. Meaningful improvement was seen in the treated as opposed to the untreated sides overall as to the amount of sebum present on the skin, and the rate of sebum accumulation was on average significantly lower on the treated side as compared to the untreated side.

In terms of the subjective ratings, also, the treated side on average was no more shiny after 6 hours than was the untreated side an hour after the soap and water washing, and was less shiny than the untreated side 2 hours after the washing. The treated side was significantly less shiny overall than the untreated side, and was significantly slower in regaining a shiny appearance. It will be understood that while various embodiments of the invention have been described and exemplified herein, a number of modifications and variations to these embodiments can be made which nevertheless do not depart in principle from the invention, and that these modifications and variations are therefore considered within the scope of the invention as defined by the claims below.

Claims

1. A cosmetic lotion, comprising:

an amount of one or more sebum-imbibing, sebum- retaining polymers which is effective for suppressing oily shine on the face of a user; and

an amount of one or more naturalizing agents which is effective for enabling the formation of a generally invisible shine-suppressing film of the one or more sebum-imbibing, sebum-retaining polymers on the face of a user.

2. A cosmetic lotion as defined in Claim 1, wherein the lotion is effective for suppressing oily shine on the face of a user for a period of at least 3 hours.

3. A cosmetic lotion as defined in Claim 1, wherein the lotion is effective for suppressing oily shine on the face of a user for a period of at least 6 hours. 4. A cosmetic lotion as defined in Claim 1, wherein the lotion is effective for suppressing oily shine on the face of a user for a period of at least 8 hours.

5. A cosmetic lotion as defined in any of Claims 1-4, characterized by the capacity to imbibe from the face of a user a volume of sebum at least equalling one-half the volume of the one or more sebum-imbibing polymers in the lotion.

6. A cosmetic lotion as defined in any of Claims 1-4, characterized by the capacity to imbibe from the face of a user a volume of sebum at least equalling the volume of the one or more sebum-imbibing polymers in the lotion.

7. A cosmetic lotion as defined in Claim 6, wherein the one or more sebum-imbibing polymers comprise from 1 to 40 percent by weight of the lotion.

8. A cosmetic lotion as defined in Claim 1, wherein the one or more sebum-imbibing, sebum-retaining polymers are cross-linked to an extent whereby the lotion is substantially nonsticky throughout the suppression of oily shine.

9. A cosmetic lotion as defined in Claims 1 or 8, wherein the lotion is substantially free of materials in addition to the one or more sebum-imbibing, sebum- retaining polymers which have a solubility parameter of from 7 to 11 (cal/cm3)ι2. 10. A cosmetic lotion as defined in Claim 1, wherein the one or more naturalizing agents include lecithin.

11. A cosmetic lotion as defined in Claim 1, wherein the one or more naturalizing agents include propylene glycol.

12. A cosmetic lotion as defined in Claim 1, wherein the one or more naturalizing agents include a mixture of cetyl and stearyl alcohols.

13. A cosmetic lotion as defined in Claim 1, wherein the one or more naturalizing agents include one or more plasticizers.

14. A cosmetic lotion as defined in Claim 1 which comprises one or more sebum-imbibing, sebum- retaining polymers and a single naturalizing agent, wherein the naturalizing agent has a refractive index which is between the refractive indices of the one or more sebum-imbibing polymers and the refractive index of the air around the user.

15. A cosmetic lotion for the sustained, non- sticky suppression of oily shine on the face, comprising:

from 8 to 16 percent by weight of a copolymer of lauryl methacrylate and isobornyl methacrylate monomer units cross-linked with at least 0.5 percent by weight of the polymer of divinylbenzene, wherein the isobornyl methacrylate and lauryl methacrylate monomer units are employed in the copolymer in a 56 part to a 44 part ratio by weight of isobornyl methacrylate units to lauryl methacrylate units; and

one of:

from 1 to 10 percent by weight of lecithin; or

from 1 to 10 percent by weight of propylene glycol; or

from 0.6 to 6 percent by weight of a mixture of cetyl and stearyl alcohols.