Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2000-04-05
2003-04-22
Zalukaeva, Tatyana (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C525S299000, C525S305000, C525S314000, C528S183000, C528S258000, C528S263000, C528S298000, C528S303000, C528S307000, C528S310000, C528S318000, C528S331000
Reexamination Certificate
active
06552146
ABSTRACT:
The present invention relates to a composition, in particular a cosmetic or pharmaceutical composition, comprising, in an appropriate medium, at least one polymer with a highly specific ordered structure. These compositions find a specific application in the field of make-up and are capable of being applied to keratinous fibres, in particular to the nails, eyelashes, eyebrows and hair.
Compositions to be applied to keratinous fibres, such as nail varnishes or nail care bases, usually comprise a film-forming polymer in solution or dispersion in an organic or aqueous solvent, colouring materials, such as dyes or pigments, and generally plasticizers and rheological agents.
Mention is very particularly be made, among the main characteristics which nail varnishes should possess, of the absence of irritation of the skin and nails, ready application, a rapid drying time and the production of a homogeneous film which has excellent gloss.
Furthermore, there is also a search for compositions which result in the formation of a film which exhibits a degree of flexibility, indeed even of suppleness, leading to good resistance to chipping of the varnish, in particular in the case of impacts, and to the formation of sufficiently hard films (surface hardness) to moderate, indeed even avoid, wearing of the film in the case of rubbing movements.
It is therefore usual, in preparing nail varnishes, to employ film-forming materials, such as nitrocellulose, if preferred in combination with another polymer, such as an acrylic resin or an alkyd resin, and with plasticizers. The role of the plasticizers is to confer suppleness on the make-up film. This is because the use of a film-forming polymer alone generally gives a rigid, brittle and delicate film which rapidly wears away. However, the addition of a plasticizer can sometimes lead to other disadvantages, such as yellowing of the film, instability of the composition with regard to light and/or heat, lack of gloss and lack of fluidity.
Furthermore, the majority of compositions known to date exhibit the fault of rapidly wearing away at the surface, which obliges the user to renew, at very frequent time intervals, the application of a fresh layer of varnish after removing the damaged layer. It may be noted that the solutions provided for overcoming this wear include the incorporation in the composition of agents having properties of toughening the film, such as silica.
It is thus found that, to date, it has proved to be particularly complicated to obtain a compromise between suppleness/flexibility of the film, on the one hand, and hardness of the film, on the other hand. It is this problem which forms the basis of the present invention.
This is because the inventor has been posed the problem of succeeding in producing a film exhibiting a degree of flexibility/suppleness, resulting in good resistance to chipping, while being sufficiently hard to moderate the wearing thereof in the case of rubbing movements.
Thus, a subject-matter of the present invention is a polymer with a “star” structure represented by the following formula (I):
A-[(M1)
p1
-(M2)
p2
. . . (Mi)
pj
]
n
in which:
A represents a polyfunctional centre, with a functionality of “n”, n being an integer greater than or equal to 2,
[(M1)
p1
-(M2)
p2
. . . (Mi)
pj
] represents a polymer chain, also known as a “branch”, composed of identical or different polymerized monomers Mi having a polymerization index pj, each branch being identical or different and being grafted covalently to the centre A;
being greater than or equal to 2 and pj being greater than or equal to 2;
the polymer comprising one or more monomers Mi chosen from polymerized monomers Mk, which may be identical or different, wherein a homopolymer formed by the corresponding polymerized monomers Mk has a Tg of greater than or equal to approximately 0° C., preferably of greater than or equal to 5° C. and even better still of greater than or equal to 10° C.; this or these monomers Mi being present, in the final polymer, in an amount of approximately 55-98% by weight, preferably in an amount of 75-95% by weight and even better still in an amount of 80-90% by weight with respect to the total weight of monomers; and
the polymer furthermore comprising one or more monomers Mj chosen from polymerized monomers Mj, which may be identical or different, wherein a homopolymer formed by the corresponding polymerized monomers Mj has a Tg of less than or equal to approximately 0° C., preferably of less than or equal to −5° C. and even better still of less than or equal to −10° C.; this or these monomers Mj being present, in the final polymer, in an amount of approximately 2-45% by weight, preferably in an amount of 5-25% by weight and even better still in an amount of 10-20% by weight with respect to the total weight of monomers.
Another subject-matter of the invention is a composition comprising, in a physiologically acceptable medium, at least one polymer as defined above.
Another subject-matter of the invention is a process for the cosmetic treatment of the hair, eyelashes, eyebrows or nails, characterized in that it comprises applying, to the latter, a cosmetic composition as defined above.
Another subject-matter of the invention is the use of at least one polymer as above in a cosmetic composition or for the preparation of a pharmaceutical composition which makes it possible to obtain a film exhibiting good resistance to chipping, to impacts, to rubbing movements, to scratches and/or to pressing actions.
The inventor has found that, on using the polymers as claimed, a composition is obtained which is easy to apply and which results in a homogeneous film with excellent gloss.
Furthermore, the film obtained exhibits a longer lifetime, due to its improved resistance to attacks, such as impacts, rubbing movements, scratches or pressing actions.
The compositions according to the invention can be readily applied and spread easily, in particular over the nails. The compositions according to the invention especially find a particularly advantageous application in the field of making up or caring for keratinous fibres, such as the nails, whether natural or artificial, eyelashes, eyebrows and hair, including body hair.
The composition according to the invention therefore comprises a polymer, the “star” structure of which can be illustrated, in a general way, by the following formula (I):
A-[(M1)
p1
-(M2)
p2
. . . (Mi)
pj
]
n
in which:
A represents a polyfunctional centre, with a functionality of “n”, n being an integer greater than or equal to 2, preferably of between 4 and 10,
[(M1)
p1
-(M2)
p2
. . . (Mi)
pj
] represents a polymeric chain, also known as a “branch”, composed of identical or different polymerized monomers Mi having a polymerization index pj, each branch being identical or different and being grafted covalently to the centre A;
i being greater than or equal to 2, preferably of between 2 and 10; and
pj being greater than or equal to 2, preferably of between 10 and 20,000.
The polymer chains are preferably provided in the form of blocks with a molecular mass of greater than or equal to 500 which can range up to 2,000,000.
In a preferred embodiment, the polymer used in the context of the present invention can be obtained by controlled radical polymerization, also known as “living” radical polymerization. This technique makes it possible in particular to overcome the limitations inherent in conventional radical polymerization, that is to say that it makes it possible in particular to control the length of the chains of the polymer which is formed and therefore to obtain block structures.
The controlled radical polymerization makes it possible to reduce the reactions in which the growing radical species is deactivated, in particular the termination stage, which reactions, in conventional radical polymerization, interrupt the growth of the polymer chain in an irreversible and uncontrolled way.
In order to decrease the probability of termination reactions, provision has been made to block,
Finnegan Henderson Farabow Garrett & Dunner LLP
L'Oreal (S.A.)
Zalukaeva Tatyana
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