The present invention relates to novel block polymers of specific structure. These polymers comprise at least one first block and at least one second block, the two blocks advantageously being such that one of the blocks has a glass transition temperature of greater than 20°C ("rigid" block) and the other block has a glass transition temperature of less than or equal to 20°C ("flexible" block).
Polymers of similar structure are described in Patent Application EP 1 411 069. The present invention is set the objective of improving the properties of the polymers described in this document in order to obtain cosmetic compositions having improved hold at equivalent gloss.
This aim is achieved in accordance with the present invention by virtue of a block polymer comprising at least one first block and at least one second block, characterized in that the first block is obtained from at least one acrylate monomer of formula CH2=CH-COOR2 in which R2 represents a C4 to C12 cycloalkyl group and from at least one methacrylate monomer of formula CH2=C(CH3)-COOR'2 in which R'2 represents a C4 to C12 cycloalkyl group,
and characterized in that the second block is obtained from an acrylic acid monomer and from at least one monomer with a glass transition of less than or equal to 20°C.
Patent Application EP 1 411 069 describes the possibility of preparing block polymers from an acrylate monomer or from a methacrylate monomer. This document also generally describes the possibility of incorporating acrylic acid monomers. However, this document does not describe the combination of claimed characteristics, namely the mixture of an acrylate monomer and of a methacrylate monomer of the same alcohol in the rigid block and the presence of acrylic acid in the flexible block. In addition, this document does not prompt a person skilled in the art to modify the nature of the monomers in order to obtain a copolymer which makes it possible to improve the hold properties of a glossy cosmetic composition. The polymers described in this document have to be combined in order to obtain a cosmetic composition simultaneously possessing these two properties.
Thus, a subject-matter of the invention is a novel block polymer. A further subject-matter of the invention is a cosmetic composition comprising such a polymer.
Another subject-matter of the invention is also a cosmetic process for making up or caring for keratinous substances, comprising application, to the keratinous substances, of a cosmetic composition according to the invention.
The invention also relates to a process for the preparation of the block polymer and to the polymer capable of being obtained by this process.
The invention also relates to the use of the polymer according to the invention in a cosmetic composition as agent for improving the hold of the said composition while maintaining its gloss.
The invention also relates to the use of the polymer according to the invention in a composition exhibiting hold properties which are improved and good gloss.
The block polymer according to the invention comprises at least one first block and at least one second block.
The term "at least" one block is understood to mean one or more blocks.
The term "block" polymer is understood to mean a polymer comprising at least 2
distinct blocks, preferably at least 3 distinct blocks.
The first block and the second block of the polymer of the invention can advantageously be incompatible with one another.
The term "blocks incompatible with one another" is understood to mean that the blend formed by a polymer corresponding to the first block and by a polymer corresponding to the second block is immiscible in the polymerization solvent, predominant by weight, of the block polymer, at ambient temperature (25°C) and atmospheric pressure (105 Pa), for a content of the blend of the said polymers of greater than or equal to 5% by weight, with respect to the total weight of the mixture of the said polymers and of the said polymerization solvent, it being understood that:
i) the said polymers are present in the blend in a content such that the respective ratio by weight ranges from 10/90 to 90/10, and that
ii) each of the polymers corresponding to the first and second blocks has a (weight- or number-)average molecular weight equal to that of the block polymer+/-15%.
In the case of a mixture of polymerization solvents, assuming two or more solvents present in identical proportions by weight, the said blend of polymers is immiscible in at least one of them.
Of course, in the case of a polymerization carried out in a single solvent, the latter is the predominant solvent.
The block polymer according to the invention comprises at least one first block and at least one second block.
The said first and second blocks can advantageously be connected to one another via an intermediate segment comprising at least one constituent monomer of the first block and at least one constituent monomer of the second block.
The intermediate segment is a block comprising at least one constituent monomer of the first block and at least one constituent monomer of the second block of the polymer makes it possible to "compatibilize" these blocks.
Advantageously, the intermediate segment comprising at least one constituent monomer of the first block and at least one constituent monomer of the second block of the polymer is a random polymer.
Preferably, the intermediate block results essentially from constituent monomers of the first block and of the second block.
The term "essentially" is understood to mean at least to 85%, preferably at least to 90%, better still to 95% and even better still to 100%.
Advantageously, the intermediate block has a glass transition temperature Tg of between the glass transition temperatures of the first and second blocks.
The block polymer according to the invention is advantageously a film-forming block ethylenic polymer.
The term "ethylenic" polymer is understood to mean a polymer obtained by polymerization of monomers comprising an ethylenic unsaturation.
The term "film-forming" polymer is understood to mean a polymer capable of forming, by itself alone or in the presence of an additional agent which is able to form a film, a continuous film which adheres to a support, in particular to keratinous substances.
Preferably, the polymer according to the invention does not comprise silicon atoms in its backbone. The term "backbone" is understood to mean the main chain of the polymer, in contrast to the pendant sidechains.
Preferably, the polymer according to the invention is water-insoluble, that is to say that the polymer is insoluble in water or in a mixture of water and of linear or branched lower monoalcohols having from 2 to 5 carbon atoms, such as ethanol, isopropanol or n-propanol, without modification of pH, at an active substance content of at least 1% by weight, at ambient temperature (25°C).
Preferably, the polymer according to the invention is not an elastomer. The term "nonelastomeric polymer" is understood to mean a polymer which, when it is subjected to a stress targeted at drawing it (for example, by 30% relative to its initial length), does not return to a length essentially identical to its initial length when the stress ceases.
More specifically, the term "nonelastomeric polymer" denotes a polymer having an instantaneous recovery R| < 50% and a delayed recovery R2h < 70% after having undergone an elongation of 30%. Preferably, Rj is < 30% and R2h < 50%.
More specifically, the nonelastomeric nature of the polymer is determined according to the following protocol:
A polymer film is prepared by casting a solution of the polymer in a Teflon-treated matrix and then dried for 7 days in surroundings controlled at 23±5°C and 50±10% relative humidity.
A film with a thickness of approximately 100 urn is then obtained, from which the rectangular test specimens with a width of 15 mm and a length of 80 mm are cut (for example with a hollow punch).
A tensile stress is applied to the sample using a device sold under the Zwick reference, under the same temperature and humidity conditions as for the drying.
The test specimens are drawn at a rate of 50 mm/min and the distance between the clamping jaws is 50 mm, which corresponds to the initial length (I0) of the test specimen.
The instantaneous recovery Ri is determined in the following way:
- the test specimen is drawn by 30% (smax), that is to say approximately 0.3 times its
initial length (I0)
- the stress is released by applying a return rate equal to the tensioning rate, i.e.
50 mm/min, and the residual elongation of the test specimen is measured as a
percentage, after returning to zero loading stress (EJ).
The instantaneous recovery in % (Rj) is given by the formula below:
Ri = ((emax-Ei)/Emax) X 100
To determine the delayed recovery, the residual elongation of the test specimen is measured as a percentage (e2h), 2 hours after returning to the zero loading stress.
The delayed recovery in % (R2h) is given by the formula below:
(formula removed)
Purely by way of indication, a polymer according to one embodiment of the invention preferably has an instantaneous recovery Ri of 10% and a delayed recovery R2h of 30%.
The polydispersity index of the polymer of the invention is advantageously greater than
2.
The polydispersity index I of the polymer is equal to the ratio of the weight-average
mass Mw to the number-average mass Mn.
The weight-average molar masses (Mw) and the number-average molar masses (Mn) are determined by gel permeation liquid chromatography (solvent THF, calibration curve drawn up with linear polystyrene standards, refractometric detector).
The weight-average mass (Mw) of the polymer according to the invention is preferably less than or equal to 300 000; it ranges, for example, from 35 000 to 200 000 and better still from 45 000 to 150 000 g/mol.
The number-average mass (Mn) of the polymer according to the invention is preferably less than or equal to 70 000; it preferably ranges from 10 000 to 60 000 and better still from 12 000 to 50 000 g/mol.
Preferably, the polydispersity index of the polymer according to the invention is greater than 2, for example ranging from 2 to 9, preferably greater than or equal to 2.5, for example ranging from 2.5 to 8 and better still greater than or equal to 2.8 and in particular ranging from 2.8 to 6.
The block polymer of the invention comprises at least one first block and at least one second block.
The first block is advantageously obtained from at least one acrylate monomer of formula CH2=CH-COOR2 and from at least one methacrylate monomer of formula CH2=C(CH3)-COOR2 in which R2 represents a C4 to C12 cycloalkyl group. The monomers and their proportions are preferably chosen so that the glass transition temperature of the first block is greater than 20°C.
The second block is advantageously obtained from an acrylic acid monomer and from at least one monomer with a glass transition of less than or equal to 20°C.
The monomers and their proportions are preferably chosen so that the glass transition temperature of the second block is less than or equal to 20°C.
The glass transition temperatures indicated for the first and second blocks can be theoretical Tg values determined from the theoretical Tg values of the constituent monomers of each of the blocks, which can be found in a reference handbook, such as the Polymer Handbook, 3rd ed., 1989, John Wiley, according to the following relationship, referred to as the Fox Law:
(formula removed)
 being the mass fraction of the monomer i in the block under consideration and Tgi being the glass transition temperature of the homopolymer of the monomer i.
Unless otherwise indicated, the Tg values indicated for the first and second blocks in the present patent application are theoretical Tg values.
The difference between the glass transition temperatures of the first and second blocks is generally greater than 10°C, preferably greater than 20°C and better still greater than 30°C.
In the present invention, the expression:
« of between ... and ... » is intended to denote a range of values, the limits of which mentioned are excluded, and
« from ... to ...» and « ranging from ... to ...» is intended to denote a range of values, the limits of which are included.
First block
The first block preferably has a Tg of greater than 20°C, for example a Tg ranging from 20 to 170°C, preferably of greater than or equal to 50°C, for example ranging from 50°C to 160°C, in particular ranging from 90°C to 130°C.
According to one embodiment, the first block is obtained from at least one acrylate monomer of formula CH2=CH-COOR2 in which R2 represents a C4 to C12 cycloalkyl group and from at least one methacrylate monomer of formula CH2=C(CH3)-COOR'2 in which R'2 represents a C4 to C12 cycloalkyl group.
The first block can be obtained exclusively from the said acrylate monomer and from the said methacrylate monomer.
The acrylate monomer and the methacrylate monomer are preferably in proportions by weight of between 30:70 and 70:30, preferably between 40:50 and 50:40, in particular of the order of 50:50.
The proportion of the first block advantageously ranges from 20 to 90% by weight of the polymer, better still from 30 to 80% and even better still from 60 to 80%.
According to one embodiment, the first block is obtained by a polymerization of isobornyl methacrylate and of isobornyl acrylate.
The first block can additionally comprise:
- (meth)acrylic acid, preferably acrylic acid,
- tert-butyl acrylate,
- methacrylates of formula CH2=C(CH3)-COOR1
in which R1 represents a linear or branched unsubstituted alkyl group comprising from 1 to 4 carbon atoms, such as a methyl, ethyl, propyl or isobutyl group,
- (meth)acrylamides of formula:
(figure removed)
where R7 and R8, which are identical or different, each represent a hydrogen atom or a linear or branched C1 to C12 alkyl group, such as an n-butyl, t-butyl, isopropyl, isohexyl, isooctyl or isononyl group ; or R7 represents H and R8 represents a 1,1-dimethyl-3-oxobutyl group,
and R' denotes H or methyl. Mention may be made, as examples of monomers, of N-butylacrylamide, N-(t-butyl)acrylamide, N-isopropylacrylamide, N,N-dimethylacrylamide and N,N-dibutylacrylamide,
- and their mixtures.
Second block
The second block advantageously has a glass transition temperature Tg of less than or equal to 20°C, for example a Tg ranging from -100 to 20°C, preferably of less than or equal to 15°C, in particular ranging from -80°C to 15°C, and better still of less than or
equal to 10°C, for example ranging from -100°C to 10°C, in particular ranging from -30°Cto 10°C.
The second block is obtained from an acrylic acid monomer and from another monomer having a Tg of less than or equal to 20°C.
The monomer having a Tg of less than or equal to 20°C is preferably chosen from the following monomers:
- acrylates of formula CH2=CHCOOR3,
R3 representing a linear or branched unsubstituted C1 to C12 alkyl group, with the exception of the tert-butyl group, in which is/are optionally inserted one or more heteroatoms chosen from O, N and S ;
- methacrylates of formula CH2=C(CH3)-COOR4,
R4 representing a linear or branched unsubstituted C6 to C12 alkyl group in which is/are optionally inserted one or more heteroatoms chosen from O, N and S;
- vinyl esters of formula R5-CO-O-CH=CH2,
where R5 represents a linear or branched C4 to C12 alkyl group;
- esters of vinyl alcohol and of C4 to C12 alcohol;
- N-(C4 to C12 alkyl)acrylamides, such as N-octylacrylamide ;
- and their mixtures.
The preferred monomers having a Tg of less than or equal to 20°C are isobutyl acrylate, 2-ethylhexyl acrylate and their mixtures in all proportions.
Each of the first and second blocks can comprise a minor proportion of at least one constituent monomer of the other block.
Thus, the first block can comprise at least one constituent monomer of the second block, and vice versa.
Each of the first and/or second blocks can comprise, in addition to the monomers indicated above, one or more other monomers, referred to as additional monomers, different from the main monomers mentioned above.
The nature and the amount of this or of these additional monomers are chosen so that the block in which they occur has the desired glass transition temperature.
This additional monomer is chosen, for example, from :
- monomers possessing ethylenic unsaturation(s) comprising at least one tertiary
amine functional group, such as 2-vinylpyridine, 4-vinylpyridine,
dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate,
dimethylaminopropylmethacrylamide and the salts of these,
- methacrylates of formula CH2=C(CH3)-COOR6,
in which R6 represents a linear or branched alkyl group comprising from 1 to 4 carbon atoms, such as a methyl, ethyl, propyl or isobutyl group, the said alkyl group being substituted by one or more substituents chosen from hydroxyl groups (such as 2-hydroxypropyl methacrylate or 2-hydroxyethyl methacrylate) and halogen atoms (Cl, Br, I, F), such as trifluoroethyl methacrylate,
- methacrylates of formula CH2=C(CH3)-COOR9,
R9 representing a linear or branched C6 to C12 alkyl group in which is/are optionally inserted one or more heteroatoms chosen from O, N and S, the said alkyl group being substituted by one or more substituents chosen from hydroxyl groups and halogen atoms (Cl, Br, I, F);
- acrylates of formula CH2=CHCOOR10,
R10 representing a linear or branched C1 to C12 alkyl group substituted by one or more substituents chosen from hydroxyl groups and halogen atoms (Cl, Br, I and F), such as 2-hydroxypropyl acrylate and 2-hydroxyethyl acrylate, or R10 representing a (C1 to C12 alkyl)-O-POE (polyoxyethylene) with repetition of the oxyethylene unit from 5 to 30 times, for example methoxy-POE, or R10 representing a polyoxyethylene group comprising from 5 to 30 ethylene oxide units.
The additional monomer can represent 0.5 to 30% by weight of the weight of the polymer. According to one embodiment, the polymer of the invention does not comprise an additional monomer.
Preferably, the polymer of the invention comprises at least isobornyl acrylate and isobornyl methacrylate monomers in the first block and isobutyl acrylate and acrylic acid monomers in the second block.
Preferably, the polymer comprises at least isobornyl acrylate and isobornyl methacrylate monomers in an equivalent proportion by weight in the first block and isobutyl acrylate and acrylic acid monomers in the second block.
Preferably, the polymer comprises at least isobornyl acrylate and isobornyl methacrylate monomers in an equivalent proportion by weight in the first block and isobutyl acrylate and acrylic acid monomers in the second block, the first block representing 70% by weight of the polymer.
Preferably, the polymer comprises at least isobornyl acrylate and isobornyl methacrylate monomers in an equivalent proportion by weight in the first block and isobutyl acrylate and acrylic acid monomers in the second block, the block with a Tg of greater than 20°C representing 70% by weight of the polymer and acrylic acid representing 5% by weight of the polymer.
According to one embodiment, the polymer comprises from 1 to 10% by weight, preferably from 3 to 8% by weight, of acrylic acid monomer.
According to one embodiment, the second block is obtained from an acrylic acid monomer and from an acrylate monomer of formula CH2=CHCOOR3, R3 representing a linear or branched unsubstituted C, to C12 alkyl group, with the exception of the tert-butyl group, in which is/are optionally inserted one or more heteroatoms chosen from O, N and S. In this case, the acrylic acid monomer and the acrylate monomer are advantageously in proportions by weight of between 10:90 and 20:80, preferably of the order of 30:70, in the second block.
Another subject-matter of the invention is a process for the preparation of a polymer which consists in mixing, in the same reactor, a polymerization solvent, an initiator, an acrylic acid monomer, at least one monomer with a glass transition of less than or equal to 20°C,
at least one acrylate monomer of formula CH2=CH-COOR2 in which R2 represents a C4 to C12 cycloalkyl group and at least one methacrylate monomer of formula CH2=C(CH3)-COOR'2 in which R'2 represents a C4 to C12 cycloalkyl group, according to the following sequence of stages:
a portion of the polymerization solvent and a portion of the initiator are run into the reactor, which mixture is heated to a reaction temperature of between 60 and 120°C,
- the said at least one acrylate monomer of formula CH2=CH-COOR2 and the
said at least one methacrylate monomer of formula CH2=C(CH3)-COOR'2
are subsequently run in, in a first fluid addition, and are left to react for a
time T corresponding to a degree of conversion of the said monomers of at
most 90%,
- subsequently, in a second fluid addition, again polymerization initiator, the
acrylic acid monomer and the said at least one monomer with a glass
transition of less than or equal to 20°C are run into the reactor and are left
to react for a time T at the end of which the degree of conversion of the
said monomers reaches a plateau,
- the reaction mixture is brought back to ambient temperature.
The term « polymerization solvent » is understood to mean a solvent or a mixture of solvents. The polymerization solvent can be chosen in particular from ethyl acetate, butyl acetate, alcohols, such as isopropanol or ethanol, aliphatic alkanes, such as isododecane, and their mixtures. Preferably, the polymerization solvent is a mixture of butyl acetate and isopropanol or isododecane.
The ratio by weight of the polymerization solvent to the polymer obtained can advantageously be between 40 and 60% at the end of the reaction. The polymerization initiator can be a peroxide.
Advantageously, an additional amount of polymerization solvent can be run in during the second fluid addition, in addition to the polymerization solvent run in before the first fluid addition.
According to another embodiment, a subject-matter of the invention is a process for the preparation of a polymer which consists in mixing, in the same reactor, a polymerization solvent, an initiator, an acrylic acid monomer, at least one monomer with a glass transition
of less than or equal to 20°C, at least one acrylate monomer of formula CH2=CH-COOR2 in which R2 represents a C4 to C12 cycloalkyl group and at least one methacrylate monomer of formula CH2=C(CH3)-COOR'2 in which R'2 represents a C4 to C12 cycloalkyl group, according to the following sequence of stages:
- a portion of the polymerization solvent and a portion of the initiator are run
into the reactor, which mixture is heated to a reaction temperature of
between 60 and 120°C,
- subsequently, in a first fluid addition, the acrylic acid monomer and the said
at least one monomer with a glass transition of less than or equal to 20°C
are run in and are left to react for a time 1 corresponding to a degree of
conversion of the said monomers of at most 90%,
- subsequently, in a second fluid addition, again polymerization initiator, the
said at least one acrylate monomer of formula CH2=CH-COOR2 and the
said at least one methacrylate monomer of formula CH2=C(CH3)-COOR'2
are run into the reactor and are left to react for a time T at the end of which
the degree of conversion of the said monomers reaches a plateau,
the reaction mixture is brought back to ambient temperature.
The polymerization temperature is preferably of the order of 90°C.
The reaction time after the second fluid addition is preferably between 3 and 6 hours.
The monomers employed in the context of this process and their proportions can be those described above.
In particular, the acrylic acid can represent from 1 to 10% by weight, preferably from 3 to 8% by weight, of the weight of all the monomers introduced into the reactor. Furthermore, the acrylic acid monomer and the monomer with a glass transition of less than or equal to 20°C can advantageously be in proportions by weight of between 10:90 and 20:80, preferably of the order of 30:70.
Another subject-matter of the invention is a polymer capable of being obtained by the process described above.
The invention also relates to cosmetic compositions comprising at least one polymer of specific structure such as has been described above.
Generally, these compositions comprise from 0.1 to 60% by weight of active material (or dry matter) of the polymer according to the invention or of the polymer capable of being obtained by the process of the invention, preferably from 0.5 to 50% by weight and more preferably from 1 to 40% by weight.
These cosmetic compositions according to the invention comprise, in addition to the said polymers, a physiologically acceptable medium, that is to say a medium compatible with keratinous substances, such as the skin, hair, eyelashes, eyebrows and nails.
The said physiologically acceptable medium generally comprises an appropriate physiologically acceptable solvent.
The composition can thus comprise a hydrophilic medium comprising water or a mixture of water and of hydrophilic organic solvent(s), such as alcohols and in particular linear or branched lower monoalcohols having from 2 to 5 carbon atoms, such as ethanol, isopropanol or n-propanol, and polyols, such as glycerol, diglycerol, propylene glycol, sorbitol, pentylene glycol and polyethylene glycols, or alternatively hydrophilic C2 ethers and hydrophilic C2-C4 aldehydes.
The water or the mixture of water and of hydrophilic organic solvents can be present in the composition according to the invention in a content ranging from 0.1% to 99% by weight, with respect to the total weight of the composition, and preferably from 10% to 80% by weight.
The composition can comprise, in addition to the block polymer described above according to the invention, an additional polymer, such as a film-forming polymer. According to the present invention, the term "film-forming polymer" is understood to mean a polymer capable of forming, by itself alone or in the presence of an additional agent which is able to form a film, a continuous film which adheres to a support, in particular to keratinous substances.
Mention may be made, among the film-forming polymers which can be used in the composition of the present invention, of synthetic polymers of radical type or of polycondensate type, polymers of natural origin and their blends. Mention may in particular be made, as film-forming polymer, of acrylic polymers, polyurethanes, polyesters, polyamides, polyureas or cellulose polymers, such as nitrocellulose.
The composition can also comprise a fatty phase composed in particular of fatty substances which are liquid at ambient temperature (generally 25°C) and/or of fatty substances which are solid at ambient temperature, such as waxes, pasty fatty substances, gums and their mixtures. These fatty substances can be of animal, vegetable, mineral or synthetic origin. This fatty phase can additionally comprise lipophilic organic solvents.
Mention may be made, as fatty substances which are liquid at ambient temperature, often referred to as oils, which can be used in the invention, of: hydrocarbon oils of animal origin, such as perhydrosqualene ; vegetable hydrocarbon oils, such as liquid triglycerides of fatty acids with 4 to 10 carbon atoms, such as triglycerides of heptanoic or octanoic acids, or also sunflower, maize, soybean, grape seed, sesame, apricot, macadamia, castor or avocado oils, triglycerides of caprylic/capric acids, jojoba oil or shea butter; linear or branched hydrocarbons of mineral or synthetic origin, such as liquid paraffins and their derivatives, liquid petrolatum, polydecanes or hydrogenated polyisobutene, such as parleam ; synthetic esters and ethers, in particular of fatty acids, such as, for example, Purcellin oil, isopropyl myristate, 2-ethylhexyl palmitate, 2-octyldodecyl stearate, 2-octyldodecyl erucate or isostearyl isostearate; hydroxylated esters, such as isostearyl lactate, octyl hydroxystearate, octyldodecyl hydroxystearate, diisostearyl malate, triisocetyl citrate or heptanoates, octanoates or decanoates of fatty alcohols ; polyol esters, such as propylene glycol dioctanoate, neopentyl glycol diheptanoates, diethylene glycol diisononanoate and pentaerythritol esters; fatty alcohols having from 12 to 26 carbon atoms, such as octyldodecanol, 2-butyloctanol, 2-hexyldecanol, 2-undecylpentadecanol or oleyl alcohol; partially hydrocarbon-comprising and/or silicone-comprising fluorinated oils ; silicone oils, such as volatile or nonvolatile and linear or cyclic polymethylsiloxanes (PDMSs) which are liquid or pasty at ambient temperature, such as cyclomethicones, dimethicones, optionally comprising a phenyl group, such as phenyl trimethicones, phenyltrimethylsiloxydiphenylsiloxanes, diphenylmethyldimethyltrisiloxanes, diphenyl dimethicones, phenyl dimethicones, polymethylphenylsiloxanes; and their mixtures.
These oils can be present in a content ranging from 0.01 to 90% by weight and better still from 0.1 to 85% by weight, with respect to the total weight of the composition.
The term "pasty fatty substance" is understood to mean a viscous product comprising a liquid fraction and a solid fraction. The term "pasty fatty substance" within the meaning of the invention is understood to mean fatty substances having a melting point ranging from
20 to 55°C, preferably 25 to 45°C, and/or a viscosity at 40°C ranging from 0.1 to 40 Pa.s (1 to 400 poises), preferably 0.5 to 25 Pa.s, measured with a Contraves TV or Rheomat 80. A person skilled in the art can choose, from the MS-r3 and MS-r4 spindles, on the basis of his general knowledge, a spindle which makes it possible to measure the viscosity, so as to be able to carry out the measurement of the viscosity of the pasty compound tested.
The melting point values correspond, according to the invention, to the melting peak measured by the differential scanning calorimetry method with a rise in temperature of 5 or 10°C/min.
Use may be made of one or more pasty fatty substances. Preferably, these fatty substances are hydrocarbon compounds (comprising mainly carbon and hydrogen atoms and optionally ester groups), optionally of polymer type ; they can also be chosen from silicone and/or fluorinated compounds ; they can also be provided in the form of a mixture of hydrocarbon and/or silicone and/or fluorinated compounds. In the case of a mixture of different pasty fatty substances, use is predominantly made, preferably, of pasty hydrocarbon compounds.
Mention may be made, among the pasty compounds capable of being used in the composition according to the invention, of lanolins and lanolin derivatives, such as acetylated lanolins or oxypropylenated lanolins or isopropyl lanolate, having a viscosity of 18 to 21 Pa.s, preferably 19 to 20.5 Pa.s, and/or a melting point of 30 to 55°C, and their mixtures. Use may also be made of esters of fatty acids or of fatty alcohols, in particular those having 20 to 65 carbon atoms (melting point of the order of 20 to 35°C and/or viscosity at 40°C ranging from 0.1 to 40 Pa.s), such as triisostearyl citrate or cetyl citrate ; arachidyl propionate ; poly(vinyl laurate); cholesterol esters, such as triglycerides of vegetable origin, such as hydrogenated vegetable oils, viscous polyesters, such as poly(12-hydroxystearic acid), and their mixtures. Use may be made, as triglycerides of vegetable origin, of derivatives of hydrogenated castor oil, such as "Thixinr" from Rheox.
Mention may also be made of silicone pasty fatty substances, such as polydimethylsiloxanes (PDMSs) having pendant chains of alkyl or alkoxy type having from 8 to 24 carbon atoms and a melting point of 20-55°C, such as stearyl dimethicones, in particular those sold by Dow Corning under the trade names of DC2503 and DC25514, and their mixtures.
The pasty fatty substance or substances can be present in the composition in a proportion of 0.5 to 60% by weight, with respect to the total weight of the composition, preferably in a proportion of 2-45% by weight and more preferably still in a proportion of 5-30% by weight.
The composition according to the invention can also comprise one or more cosmetically acceptable (acceptable tolerance, acceptable toxicology and acceptable feel) organic solvents.
These solvents can generally be present in a content ranging from 0 to 90%, preferably from 0.1 to 90%, more preferably from 10 to 90%, by weight, with respect to the total weight of the composition, and better still from 30 to 90%.
Mention may be made, as solvents which can be used in the composition of the invention, in addition to the hydrophilic organic solvents mentioned above, of ketones which are liquid at ambient temperature, such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, isophorone, cyclohexanone or acetone ; propylene glycol ethers which are liquid at ambient temperature, such as propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate or dipropylene glycol mono(n-butyl) ether; short-chain esters (having from 3 to 8 carbon atoms in total), such as ethyl acetate, methyl acetate, propyl acetate, n-butyl acetate or isopentyl acetate ; ethers which are liquid at ambient temperature, such as diethyl ether, dimethyl ether or dichlorodiethyl ether; alkanes which are liquid at ambient temperature, such as decane, heptane, dodecane, isododecane or cyclohexane, cyclic aromatic compounds which are liquid at ambient temperature, such as toluene and xylene; aldehydes which are liquid at ambient temperature, such as benzaldehyde or acetaldehyde, and their mixtures.
The term "wax" within the meaning of the present invention is understood to mean a lipophilic compound which is solid at ambient temperature (25°C), which exhibits a reversible solid/liquid change in state and which has a melting point of greater than or equal to 30°C which can range up to 120°C.
On bringing the wax to the liquid state (melting), it is possible to render it miscible with oils possibly present and to form a microscopically homogeneous mixture but, on bringing the temperature back to ambient temperature, recrystallization of the wax in the oils of the mixture is obtained. The melting point of the wax can be measured using a differential
scanning calorimeter (DSC), for example the calorimeter sold under the name DSC 30 by Metier.
The wax can also exhibit a hardness ranging from 0.05 MPa to 15 MPa and preferably ranging from 6 MPa to 15 MPa. The hardness is determined by the measurement of the compressive force, measured at 20°C using the texture analyzer sold under the name TA-TX2i by Rheo, equipped with a stainless steel cylinder with a diameter of 2 mm which is displaced at the measurement rate of 0.1 mm/s and which penetrates into the wax to a depth of penetration of 0.3 mm.
The waxes can be hydrocarbon, fluorinated and/or silicone waxes and can be of vegetable, mineral, animal and/or synthetic origin. In particular, the waxes exhibit a melting point of greater than 25°C and better still of greater than 45°C. Mention may be made, as wax which can be used in the composition of the invention, of beeswax, carnauba wax, candelilla wax, paraffin wax, microcrystalline waxes, ceresin or ozokerite ; synthetic waxes, such as polyethylene waxes or Fischer-Tropsch waxes, silicone waxes, such as alkyl or alkoxy dimethicones having from 16 to 45 carbon atoms.
The gums are generally polydimethylsiloxanes (PDMSs) of high molecular weight or cellulose gums or polysaccharides and the pasty substances are generally hydrocarbon compounds, such as lanolins and their derivatives or else PDMSs.
The nature and the amount of the solid substances depend on the mechanical properties and textures desired. By way of indication, the composition can comprise from 0 to 50% by weight of waxes, with respect to the total weight of the composition, and better still from 1 to 30% by weight.
The polymer can be used in combination with one or more additional agents which are able to form a film. Such an agent which is able to form a film can be chosen from any compound known to a person skilled in the art as being capable of fulfilling the desired function and can in particular be chosen from plasticizers and coalescence agents.
The composition according to the invention can additionally comprise one or more colouring materials chosen from water-soluble dyes and pulverulent colouring materials, such as pigments, pearlescent agents and glitter, well known to a person skilled in the art. The colouring materials can be present in the composition in a content ranging from 0.01%
to 50% by weight, with respect to the weight of the composition, preferably from 0.01% to 30% by weight.
The term "pigments" should be understood as meaning white or coloured and inorganic or organic particles of any shape which are insoluble in the physiological medium and which are intended to colour the composition.
The term "pearlescent agents" should be understood as meaning iridescent particles of any shape produced in particular by certain molluscs in their shells or else synthesized.
The pigments can be white or coloured and inorganic or organic. Mention may be made, among inorganic pigments, of titanium dioxide, optionally surface-treated, zirconium or cerium oxides, and also zinc, iron (black, yellow or red) or chromium oxides, manganese violet, ultramarine blue, chromium hydrate and ferric blue, or metal powders, such as aluminium powder or copper powder.
Mention may be made, among organic pigments, of carbon black, pigments of D & C type, and lakes, based on cochineal carmine, of barium, strontium, calcium or aluminium.
Mention may also be made of pigments with an effect, such as particles comprising an organic or inorganic and natural or synthetic substrate, for example glass, acrylic resins, polyester, polyurethane, poly(ethylene terephthalate), ceramics or aluminas, the said substrate being covered or not being covered with metal substances, such as aluminium, gold, silver, platinum, copper or bronze, or with metal oxides, such as titanium dioxide, iron oxide or chromium oxide, and their mixtures.
The pearlescent pigments can be chosen from white pearlescent pigments, such as mica covered with titanium oxide or with bismuth oxychloride, coloured pearlescent pigments, such as titanium oxide-coated mica covered with iron oxides, titanium oxide-coated mica covered with in particular ferric blue or chromium oxide, or titanium oxide-coated mica covered with an organic pigment of the above mentioned type, and pearlescent pigments based on bismuth oxychloride. Use may also be made of interferential pigments, in particular liquid crystal or multilayer pigments.
The water-soluble dyes are, for example, beetroot juice or methylene blue.
The composition according to the invention can additionally comprise one or more fillers,
in particular in a content ranging from 0.01 % to 50% by weight, with respect to the total weight of the composition, preferably ranging from 0.01% to 30% by weight. The term "fillers" should be understood as meaning colourless or white and inorganic or synthetic particles of any shape which are insoluble in the medium of the composition, whatever the temperature at which the composition is manufactured. These fillers are used in particular to modify the rheology or the texture of the composition.
The fillers can be inorganic or organic fillers of any shape, platelet, spherical or oblong, whatever the crystallographic form (for example, leaf, cubic, hexagonal, orthorhombic, and the like). Mention may be made of talc, mica, silica, kaolin, polyamide (Nylon®) powders (Orgasol® from Atochem), poly-p-alanine powders, polyethylene powders, powders formed of tetrafluoroethylene polymers (Teflon®), lauroyllysine, starch, boron nitride, polymeric hollow microspheres, such as those of polyvinylidene chloride/ acrylonitrile, for example Expancel® (Nobel Industry), or of acrylic acid copolymers (Polytrap® from Dow Corning), silicone resin microbeads (Tospearls® from Toshiba, for example), polyorganosiloxane elastomer particles, precipitated calcium carbonate, magnesium carbonate, basic magnesium carbonate, hydroxyapatite, hollow silica microspheres (Silica Beads® from Maprecos), glass or ceramic microcapsules, or metal soaps derived from organic carboxylic acids having from 8 to 22 carbon atoms, preferably from 12 to 18 carbon atoms, for example zinc stearate, magnesium stearate, lithium stearate, zinc laurate or magnesium myristate.
The composition according to the invention can also comprise ingredients commonly used in cosmetics, such as vitamins, thickeners, trace elements, softeners, sequestering agents, fragrances, basifying or acidifying agents, preservatives, sunscreen agents, surfactants, antioxidants, agents for combating hair loss, antidandruff agents, propellants or their mixtures.
Of course, a person skilled in the art will take care to choose this or these optional additional compounds and/or their amounts so that the advantageous properties of the corresponding composition according to the invention are not, or not substantially, detrimentally affected by the envisaged addition.
The composition according to the invention can be provided in particular in the form of a suspension, dispersion, solution, gel, emulsion, in particular oil-in-water (O/W) or water-in-oil (W/O) or multiple (W/O/W or polyol/O/W or O/W/O) emulsion, cream, foam, dispersion of vesicles, in particular of ionic or nonionic lipids, two-phase or multiphase lotion, powder
or paste, in particular soft paste (in particular paste having a dynamic viscosity at 25°C of the order of 0.1 to 40 Pa-s under a shear rate of 200 s"1, after measuring for 10 minutes in cone/plate geometry). The composition can be anhydrous; for example, it can be an anhydrous paste.
A person skilled in the art can choose the appropriate dosage form and its method of preparation on the basis of his general knowledge, taking into account, on the one hand, the nature of the constituents used, in particular their solubility in the support, and, on the other hand, the application envisaged for the composition.
The composition according to the invention can be a makeup composition, such as products for the complexion (foundation), face powders, eyeshadows, products for the lips, concealers, blushers, mascaras, eyeliners, products for making up the eyebrows, lip or eye pencils, products for the nails, such as nail varnishes, products for making up the body or products for making up the hair (hair mascara).
The composition according to the invention can also be a product for caring for the skin of the body and face, in particular an antisun product or a product for colouring the skin (such as a self-tanning product).
The composition according to the invention can also be a hair product, in particular for the form retention of the hairstyle or the shaping of the hair. The hair compositions are preferably shampoos, gels, hair setting lotions, blowdrying lotions or fixing and styling compositions.
The example which follows illustrates, without impled limitation, the compositions comprising the polymer according to the invention.
Example 1 : Preparation of a polyfisobornvl acrvlate/isobornyl methacrvlate/isobutvl acrylate/acrylic acid) polymer
300 g of isododecane are introduced into a 1 litre reactor and then the temperature is increased so as to pass from ambient temperature (25°C) to 90°C in 1 hour. 105 g of isobornyl methacrylate (manufactured by Arkema), 105g of isobornyl acrylate (manufactured by Arkema) and 1.8g of 2,5-bis(2-ethylhexanoylperoxy)-2,5-
dimethylhexane (Trigonox® 141 from Akzo Nobel) are subsequently added at 90°C over 1 hour.
The mixture is maintained at 90°C for 1 h 30.
75 g of isobutyl acrylate (manufactured by Fluka), 15 g of acrylic acid and 1.2 g of 2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane are subsequently introduced into the preceding mixture, still at 90°C, over 30 minutes.
The mixture is maintained at 90°C for 3 hours and then the combined product is cooled. A solution comprising 50% of polymer active material in isododecane is obtained.
A polymer comprising a first rigid poly(isobornyl acrylate/isobornyl methacrylate) block having a Tg of 110°C, a second flexible poly(isobutyl acrylate/acrylic acid) block having a Tg of -9°C and an intermediate block which is a random isobornyl acrylate/isobornyl methacrylate/isobutyl acrylate/acrylic acid polymer is obtained.
Examples of comparative polymer, examples of polymer 2 and 3 :
The comparative example is prepared according to the teaching of Example 9 of Patent Application EP1411069: poly(isobornyl acrylate/isobornyl methacrylate/isobutyl acrylate). The procedure is recalled below:
100 g of isododecane are introduced into a 1 litre reactor and then the temperature is increased so as to pass from ambient temperature (25°C) to 90°C in 1 hour. 105g of isobornyl acrylate, 105g of isobornyl methacrylate, 110g of isododecane and 1.8g of 2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane (Trigonox® 141 from Akzo Nobel) are subsequently added at 90° C over 1 hour.
The mixture is maintained at 90°C for 1 h 30.
90 g of isobutyl acrylate, 90 g of isododecane and 1.2 g of 2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane are subsequently introduced into the preceding mixture, still at 90°C, over 30 minutes.
The mixture is maintained at 90°C for 3 hours and then the combined product is cooled. A solution comprising 50% of polymer active material in isododecane is obtained.
A polymer comprising a first poly(isobornyl acrylate/isobornyl methacrylate) block having a Tg of 128°C, a second poly(isobutyl acrylate) block having a Tg of-20°C and an intermediate block which is a random isobornyl acrylate/isobornyl methacrylate/isobutyl acrylate polymer is obtained.
Examples 2 and 3 of the invention are prepared according to the procedure described in Example 1.
Their compositions are summarized in the table below.(Table Removed)Hold towards oil of the polymers of the examples
It is measured with a drop of olive oil placed on a dry polymer film.
A polymer film is produced from a 20% solution in isododecane, 0.5 ml is spread over a 2.5 x 7.5 cm glass plate and is left to dry at ambient temperature for 24 hours. Subsequently, 1 ml of olive oil is spread over the polymer film. After the desired time (1 hour or 24 hours), the excess oil is wiped from the film and the latter is weighed in order to determine its increase in weight.
The comparative example is tacky after 1h ; an increase in weight of 5.5% is observed after 24 h, whereas for Example 3 it is nontacky after 1 h ; its increase in weight is only 1% after 24 h.
The increase in weight and the tack reflect the sensitivity of the polymer to the olive oil. The greater the sensitivity, the more readily the deposited layer will be detrimentally
affected during meals and the hold will be poorer. The hold of the polymer of Example 1 is better than that of the comparative example.
Gloss measured with a gloss meter on a dry deposited layer of polymer
The gloss can be conventionally measured by the following method using a gloss meter. A layer with a thickness of 50 urn of a 50% solution of a polymer in the synthesis solvent (isododecane) is spread using an automatic spreader over a Leneta® contrast chart with the reference Form 1A Penopac. The layer covers at least the black background of the chart. The deposited layer is left to dry for 24 hours at a temperature of 25°C and then the 20° gloss is measured on the black background using a Dr Lange® Ref 03 gloss meter.
The 20° gloss of the polymers of Examples 1, 2 and 3 is respectively equal to 80, 74 and 75, whereas the gloss of the comparative example is 71.
The 60° gloss is measured as above.
The 60° gloss of the polymers of Examples 1, 2 and 3 is respectively equal to 90, 87 and
87, whereas the gloss of the comparative example is 86.
Example of liquid gloss comprising the polymer of Example 1
The procedure for 200 g of the following formulation is as follows:
• The pigments are ground 3 times in a triple roll mill in octyldodecanol brought
beforehand to 60°C. The ground material is left to cool at ambient temperature (25°C) in a
jacketed heating pan or in a beaker.
• The copolymer, the squalane, the polybutylene, the pearlescent agents and the
fragrance are added to the ground material. The combined mixture is stirred using a
turbine mixer (type : Rayneri) in order to homogenize.
• When the mixture is homogeneous, the polyphenyltrimethylsiloxydimethylsiloxane is
added with stirring at 800 revolutions/minute with the Rayneri over approximately 30
minutes.
• Finally, the pyrogenic silica is added gradually and stirring with the turbine mixer is maintained at 1000 revolutions/minute for 20 minutes.

Name
Refined vegetable perhydrosqualene (INCI name = squalane)
2-Octyldodecanol
Rutile titanium oxide treated with alumina/silica/trimethylolpropane
Red 7
Lake Blue 1
Lake Yellow 6
Black iron oxide
Mica/titanium dioxide/brown iron oxide
Polyphenyltrimethylsiloxydimethylsiloxane 1
Hydrophobic pyrogenic silica surface-treated with dimethylsilane 3
Poly(isobornyl methacrylate-co-isobornyl acrylate-co-isobutyl acrylate-co-
acrylic acid) at an active material content of 50% in isododecane of
Example 1
Polybutylene2
Fragrance
Total

Concentration (% by weight)
10.86
15.39
2.74
0.54
0.16
2.58
0.25 2
20.03
4.5 30
10.65 0.3 100

1 : Belsil RDM 1000 from Wacker (viscosity 1000 cPs ; MW: 9000) 2:lndopolH 100(MW:920) 3: Aerosil R 972 from Degussa
This gloss composition, applied to the lips in a single movement, exhibits satisfactory properties of comfort and of gloss. The hold of the composition is also improved ; the composition does not migrate into the wrinkles and fine lines of the outline of the lips.

CLAIMS
1. Block polymer comprising at least one first block and at least one second block,
characterized in that the first block is obtained from at least one acrylate monomer of
formula CH2=CH-COOR2 in which R2 represents a C4 to C12 cycloalkyl group and from
at least one methacrylate monomer of formula CH2=C(CH3)-COOR'2 in which R'2
represents a C4 to C12 cycloalkyl group,
and characterized in that the second block is obtained from an acrylic acid monomer and from at least one monomer with a glass transition of less than or equal to 20°C.
2. Polymer according to Claim 1, characterized in that the said polymer comprises an
intermediate block comprising at least one constituent monomer of the first block and at
least one constituent monomer of the second block.
3. Polymer according to Claim 1 or 2, characterized in that the said polymer has a
polydispersity index of greater than 2.
4. Polymer according to one of the preceding claims, characterized in that the
acrylate and methacrylate are in proportions by weight of between 30:70 and 70:30,
preferably between 40:50 and 50:40, in the first block.

5. Polymer according to one of the preceding claims, characterized in that the first
block is obtained exclusively from an acrylate monomer and from a methacrylate
monomer.
6. Polymer according to one of the preceding claims, characterized in that R2 and R'2
represent an isobornyl radical.
7. Polymer according to one of the preceding claims, characterized in that the
proportion of the first block ranges from 20 to 90% by weight of the polymer, better still
from 30 to 80% and even better still from 60 to 80%.
8. Polymer according to one of the preceding claims, characterized in that the said
polymer comprises from 1 to 10% by weight, preferably from 3 to 8% by weight, of
acrylic acid monomer.
9. Polymer according to one of the preceding claims, characterized in that the second
block is obtained from an acrylic acid monomer and from an acrylate monomer of
formula CH2=CHCOOR3l R3 representing a linear or branched unsubstituted d to C12
alkyl group, with the exception of the tert-butyl group, in which is/are optionally inserted
one or more heteroatoms chosen from O, N and S.
10. Polymer according to Claim 9, characterized in that the acrylic acid monomer and
the acrylate monomer are in proportions by weight of between 10:90 and 20:80,
preferably of the order of 30:70, in the second block.
11. Polymer according to Claim 9 or 10, characterized in that the acrylate monomer is
isobutyl acrylate.
12. Polymer according to one of the preceding claims, characterized in that the second
block is obtained from acrylic acid and from isobutyl acrylate and in that the first block
is obtained from isobornyl acrylate and from isobornyl methacrylate.
13. Cosmetic composition, characterized in that it comprises a polymer according to
any one of Claims 1 to 12.
14. Cosmetic composition according to Claim 13, characterized in that it is a
composition for making up or caring for keratinous substances.
15. Cosmetic composition according to Claim 13, characterized in that it is a nail
varnish.
16. Cosmetic composition according to Claim 13, characterized in that it is a product
for making up the lips.
17. Cosmetic process for making up or caring for keratinous substances, comprising
application, to the keratinous substances, of a cosmetic composition according to one
of Claims 13 to 16.
18. Use of a polymer according to any one of Claims 1 to 12 in a cosmetic composition
as agent for improving the hold of the said composition while maintaining its gloss.
19. Process for the preparation of a polymer which consists in mixing, in the same
reactor, a polymerization solvent, an initiator, an acrylic acid monomer, at least one
monomer with a glass transition of less than or equal to 20°C, at least one acrylate
monomer of formula CH2=CH-COOR2 in which R2 represents a C4 to C12 cycloalkyl
group and at least one methacrylate monomer of formula CH2=C(CH3)-COOR'2 in
which R'2 represents a C4 to Ci2 cycloalkyl group, according to the following sequence
of stages:
a portion of the polymerization solvent and a portion of the initiator are run into the reactor, which mixture is heated to a reaction temperature of between 60 and 120°C,
- the said at least one acrylate monomer of formula CH2=CH-COOR2 and the
said at least one methacrylate monomer of formula CH2=C(CH3)-COOR'2
are subsequently run in, in a first fluid addition, and are left to react for a
time T corresponding to a degree of conversion of the said monomers of at
most 90%,
- subsequently, in a second fluid addition, again polymerization initiator, the
acrylic acid monomer and the said at least one monomer with a glass
transition of less than or equal to 20°C are run into the reactor and are left
to react for a time T' at the end of which the degree of conversion of the
said monomers reaches a plateau,
- the reaction mixture is brought back to ambient temperature.

20. Process according to Claim 19, characterized in that the reaction temperature is of
the order of 90°C.
21. Process according to either of Claims 19 and 20, characterized in that the ratio by
weight of the polymerization solvent to the polymer obtained is between 40 and 60% at
the end of the reaction.
22. Process according to either of Claims 19 and 21, characterized in that the
polymerization initiator is a peroxide.
23. Process according to one of Claims 19 to 22, characterized in that the said at least
one acrylate monomer of formula CH2=CH-COOR2 and the said at least one
methacrylate monomer of formula CH2=C(CH3)-COOR2 are run into the reactor on two
occasions: with the polymerization solvent and during the first fluid addition.
24. Process according to one of Claims 19 to 23, characterized in that polymerization
solvent is run in during the first fluid addition.
25. Process according to one of Claims 19 to 24, characterized in that polymerization
solvent is run in during the second fluid addition.
26. Process according to one of Claims 19 to 25, characterized in that the acrylate of
formula CH2=CH-COOR2 and the methacrylate CH2=C(CH3)-COOR2 are in proportions
by weight of between 30:70 and 70:30, preferably between 40:50 and 50:40.
27. Process according to one of Claims 19 to 26, characterized in that R2 represents
an isobornyl radical.
28. Process according to one of Claims 19 to 27, characterized in that the proportion
of the acrylate of formula CH2=CH-COOR2 and of the methacrylate
CH2=C(CH3)-COOR2 ranges from 20 to 90% by weight of the polymer, better still from
30 to 80% and even better still from 60 to 80%.
29. Process according to one of Claims 19 to 28, characterized in that the acrylic acid
represents from 1 to 10% by weight, preferably from 3 to 8% by weight, of the weight of
all the monomers introduced into the reactor.
30. Process according to one of Claims 19 to 29, characterized in that the monomer
with a glass transition of less than or equal to 20°C is an acrylate monomer of formula
CH2=CHCOOR3, R3 representing a linear or branched unsubstituted C, to C12 alkyl
group, with the exception of the tert-butyl group, in which is/are optionally inserted one
or more heteroatoms chosen from O, N and S.
31. Process according to one of Claims 19 to 30, characterized in that the acrylic acid
monomer and the monomer with a glass transition of less than or equal to 20°C are in
proportions by weight of between 10:90 and 20:80, preferably of the order of 30:70.
32. Process according to one of Claims 19 to 31, characterized in that the monomer
with a glass transition of less than or equal to 20°C is isobutyl acrylate.
33. Polymer capable of being obtained according to the process of one of Claims 19 to
Cosmetic composition comprising a polymer according to Claim 33 or a polymer
obtained according to the process of one of Claims 19 to 32.
34. A Block polymer, a cosmetic composition, a cosmetic process, use of a polymer
and a process for the preparation of a polymer substantially as herein described with
reference to the foregoing examples.