FR3150109A1 - Composite material of bismuth oxycarbonate and polymers for the filtration of ultraviolet radiation - Google Patents

Abstract

Composite material of bismuth oxycarbonate and polymers for filtering ultraviolet radiation The present invention relates to a composite material comprising at least one particle of bismuth oxycarbonate of formula (I) (BiO)2-x(CO3), formula (I) as well as its solvates such as hydrates, in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm; and at least one polymer, their preparation process, as well as cosmetic compositions and uses implementing said composite materials. Figure for the abstract: None

Description

Composite material of bismuth oxycarbonate and polymers for the filtration of ultraviolet radiation

The present invention relates to the field of sun protection and more particularly to composite materials of bismuth oxycarbonate and polymers, for their use in the filtration of ultraviolet radiation.

The invention also relates to a composition, in particular a cosmetic composition, comprising in particular composite materials of bismuth oxycarbonate and polymers.

Keratin materials are exposed to sunlight on a daily basis.

It is known that light rays with wavelengths between 280 nm and 400 nm allow the tanning of human epidermis. However, rays with wavelengths between 280 and 320 nm, called UV-B rays, are detrimental to the development of a natural tan. This exposure is also likely to induce an alteration of the biomechanical properties of the epidermis which results in the appearance of wrinkles leading to premature aging of the skin.

It is also known that UV-A rays, with wavelengths between 320 and 400 nm, penetrate deeper into the skin than UV-B rays. UV-A rays promote rapid and persistent pigmentation of the skin. Daily exposure to UVA radiation, even for short periods, under normal conditions, can also cause a degradation of collagen and elastin fibers, resulting in a change in the skin microrelief, the appearance of wrinkles and irregular pigmentation (i.e. brown spots, uneven skin tone, etc.).

Additionally, prolonged exposure to the sun can further dry out hair, making it brittle.

Therefore, protection of keratin materials, particularly human ones, such as skin, is essential.

To counter these undesirable effects, it is common practice to formulate organic and/or inorganic UV-A and/or UV-B filters in compositions dedicated to providing sun protection.

Many skin photoprotective cosmetic compositions have been proposed to date. They generally contain organic UV filters and/or inorganic UV filters which act according to their own chemical nature and according to their own physical properties by absorption, reflection or diffusion of UV radiation. They generally contain combinations of oil-soluble organic UV filters and/or water-soluble organic UV filters associated with metal oxide pigments such as titanium dioxide (TiO ₂ ) or zinc oxide (ZnO).

As for the usual organic filters, they must have acceptable cosmetic properties, good solubility in usual solvents, particularly in oils, but also good photostability, alone and in combination. They must also be colorless or of a color cosmetically acceptable to consumers. These organic filters are generally used in mixtures and such combinations of filters can limit the formulatory field.

In addition, photoprotection from inorganic UV filters is today a very important expectation of consumers, as they consider mineral sunscreens safer.

_TiO2 and ZnO are the most common mineral UV filters used.

However, one of the major drawbacks of such mineral filters is that, once applied to the skin, they produce a whitening effect on the skin which is cosmetically undesirable and generally not appreciated by users.

This effect is all the more marked as the concentration of mineral filters in the composition is high, which limits their concentration in sun formulations.

To avoid this problem, it would of course be possible to use reduced quantities of inorganic filter(s), but the resulting compositions, which would certainly lead to films with acceptable transparency on the skin, would then no longer offer suitable protection in the UV range, which greatly limits the interest of such an option.

In addition, the use of large quantities of these UV filters induces, in addition to significant whitening, unpleasant sensations after application to the skin, and in particular causes sensations of roughness and dryness on the skin in the case of significant and regular use of the products.

However, consumers are increasingly looking for products that are effective but also easy to apply, provide long-lasting comfort and have satisfactory sensory properties.

There therefore remains a need for inorganic UV filters which are effective in photoprotection and which do not have the drawbacks presented above.

In particular, there remains a need for inorganic UV filters capable of effectively blocking UV rays, particularly in the UV-B and UV-A range, and in particular UV-B rays, having high transparency to visible light, which do not bleach the keratin materials to which they are applied and having good cosmetic properties.

In particular, there remains a need for mineral UV filters, distinct from titanium dioxide or zinc oxide, which are just as effective, which are transparent, which do not cause a feeling of roughness and drying on the skin, and which are easily formulated, particularly at high concentrations.

The present invention aims precisely to propose new mineral UV filters making it possible to meet these expectations.

Thus, according to a first of its aspects, the present invention relates to a composite material comprising:

(a) at least one particle of bismuth oxycarbonate of formula (I) (BiO) _{2- x} (CO ₃ ), as well as its solvates such as hydrates, in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm; and

b) at least one polymer.

In particular, bismuth oxycarbonate particles are of formula (BiO) ₂ ( _CO3 ) as well as its solvates such as hydrates.

Combinations of bismuth oxide with polymers such as alginates, chitosan, polyvinyl alcohol are already proposed in various fields other than the sun protection of keratin materials such as for example radiopacity for embolization (US 8,012,454, EP 1,531,874, US 7,947,073), in medical equipment (US 6,387,978), or to combat gastric hyperacidity (US 3,257,275, US 6,024,987 A). However, these documents do not in any way mention the field of UV filtration nor do they describe composite materials comprising bismuth oxides according to the invention.

Preferably, the mass ratio of bismuth oxycarbonate particle(s) a) to polymer(s) b) varies from 0.01 to 50, preferably from 0.2 to 15, more preferably from 0.3 to 10 and more preferably from 0.5 to 8.5.

Preferably, the average size of the largest dimension of the composite material particle according to the invention is less than or equal to 1 µm, and more preferably less than or equal to 500 nm, even more preferably less than or equal to 450 nm.

In particular, the bismuth oxycarbonate particles are in the form of tubes, platelets and/or rods, preferably in the form of platelets and/or rods.

Preferably, the polymer(s) b) are chosen from polyethylene glycols, polyethylene amines, polypropylene glycols, polyvinyl alcohols, polyacrylic acids and their salts, polymethacrylic acids and their salts, polymethylmethacrylates, polyvinyl sulfonates, polystyrene sulfonates, polylactic acids and their salts, polycaprolactones, polyglycolic acids, polyacetoacetates, poly(lactic-co-glycolic) acids, celluloses and their derivatives, alginic acids and their salts, carrageenans, starches, pectins, inulins, dextrans and their derivatives, xanthan gum, ulvans, lignosulfonates and their salts, chitins and chitosans, pullulans, polyvinyl alcohols and alginic acid. polyhydroxystearic acid, and/or their copolymers, or their mixtures.

In particular, the polymer(s) b) are chosen from sodium lignosulfonates, calcium lignosulfonates, polyanetol sulfonate, sodium alginate, carboxymethylcelluloses, hydroxyethylcelluloses, dextrans sulfate salts, carrageenans, chitosans, myristoyl pullulan, polyvinyl alcohols, and/or their copolymers, or their mixtures. More particularly, the molar ratio between the number of moles of coating compound(s) and the number of moles of core compound(s) varies from 0.0001 to 20, preferably varies from 0.005 to 15, more preferably varies from 0.01 to 10, and even more preferably varies from 0.05 to 5.

Surprisingly, and as is apparent from the examples below, the inventors have discovered that the composite materials according to the invention exhibit excellent efficiency for filtering ultraviolet radiation, and in particular UV-B rays, as well as high transparency in visible radiation, and make it possible to give the composition containing them cosmetic properties that are satisfactory for the consumer.

For the purposes of the present invention, the term “ composite material ” means a heterogeneous particulate solid material comprising at least two immiscible components, the components of which are linked by physical and/or chemical interactions.

For the purposes of the present invention, the term " high transparency in visible radiation " means particles having a high transmission of rays between 400 and 780 nm.

For the purposes of the present invention, the term " efficiency for filtering ultraviolet radiation " means particles having an absorbance threshold in the UV, in the dispersion medium comprising said particles at a mass fraction of 0.005%, greater than 0.25, preferably greater than or equal to 0.30, and more preferably still greater than or equal to 0.35. The higher the absorbance threshold, the greater the efficiency of filtering UV radiation.

UV-B radiation means the wavelength range from 280 to 320 nm. UV-A radiation means the wavelength range from 320 to 400 nm. Visible light means the wavelength range from 400 to 780 nm.

Thus, for the purposes of the present invention, the term " UV filter " is intended to denote any compound that filters ultraviolet (UV) radiation in the wavelength range from 280 nm to 400 nm. The term " UV-B filter " is intended to denote any compound that filters ultraviolet (UV) radiation in the wavelength range from 280 nm to 320 nm. The term "UV-A filter" is intended to denote any compound that filters ultraviolet (UV) radiation in the wavelength range from 320 nm to 400 nm.

For the purposes of the present invention, the term "fatty substance" means an organic compound which is immiscible in water at ordinary temperature (25°C) and at atmospheric pressure (760 mm Hg) (solubility less than 5%, and preferably 1%, even more preferably 0.1%); in addition, the fatty substances are miscible in particular in all proportions in organic solvents under the same temperature and pressure conditions, such as for example in halogenated solvents such as chloroform, dichloromethane, lower alcohols such as ethanol or aromatic solvents such as benzene or toluene.

By"salt of ' organic or mineral acid", we mean more particularly the salts chosen from a salt derived from i) hydrochloric acid HCl, ii) hydrobromic acid HBr, iii) sulfuric acid H₂SO₄, iv) alkylsulfonic acids: Alk-S(O)₂OH such as methylsulfonic acid and ethylsulfonic acid;v) arylsulfonic acids: Ar-S(O)₂OH such as benzenesulfonic acid and toluenesulfonic acid; (vi) citric acid; (vii) succinic acid; (viii) tartaric acid; (ix) lactic acid; (x) alkoxysulfinic acids: Alk-O-S(O)OH such as methoxysulfinic acid and ethoxysulfinic acid; (xi) aryloxysulfinic acids such as tolueneoxysulfinic acid and phenoxysulfinic acid; (xii) phosphoric acid H₃PO₄ ; xiii) acetic acid CH₃C(O)OH; xiv) triflic acid CF₃SO₃H and xv) of tetrafluoroboric acid HBF₄; as well as salts of so-called “acidic” amino acids such as salts of glutamic acid, aspartic acid.

By " salts of organic or mineral bases " is meant salts of bases or alkaline agents as defined below as alkali metal hydroxides such as soda, potash, ammonia, amines or alkanolamines or salts of so-called "basic" amino acids such as lysine or arginine.

By " cationic counterion " is meant a cation or a cationic group derived from an organic or mineral base salt counterbalancing an anionic charge of at least one ingredient of the composition according to the invention, more particularly the cationic counterion is chosen from i) alkali metals such as sodium, potassium, preferably Na ⁺ , ii) alkaline earth metals such as calcium, iii) ammonium R ₄ N ⁺ with R, identical or different, representing a hydrogen atom, or a (C ₁ -C ₆ )alkyl group optionally substituted by one or more hydroxyl groups, preferably R represents a hydrogen atom or a (C ₁ -C ₄ )alkyl group such as methyl.

This effectiveness of the composite materials according to the invention is, to the knowledge of the inventors, characterized for the first time. It has never been proposed to implement composite materials of bismuth oxycarbonate and polymer in cosmetic compositions intended for the effective filtration of UV radiation, in particular UV-B radiation.

The composite materials according to the invention are in particular intended to protect keratin materials, in particular the skin and hair, from UV radiation, in particular in cosmetic compositions for the fields of sun protection, care, hair treatment and makeup.

Thus, according to another aspect, the present invention also relates to the non-therapeutic cosmetic use of a composite material according to the invention, for filtering UV radiation, preferably UV-B, comprising at least the application to keratin materials of a composition comprising a composite material according to the invention.

The present invention also relates to a non-therapeutic cosmetic process for filtering UV radiation, preferably UV-B, comprising at least the application to keratin materials of a composition comprising the composite materials of bismuth oxycarbonate and polymer as defined above.

The present invention also relates to methods of preparing the composite materials according to the invention.

By “ keratin materials ” we mean in particular the skin, including the scalp, the lips, and also keratin fibres such as the hair, eyelashes, eyebrows, in particular the skin and/or the hair, and preferably the skin.

The expression " at least one " is equivalent to " one or more ".

The expressions “ between … and … ”, “ includes from … to … ”, “ formed from … to … ”, and “ ranging from … to … ” must be understood inclusively, unless otherwise specified.

Other characteristics, variants and advantages of the compositions according to the invention will emerge more clearly upon reading the description and examples which follow.

represents the absorbance spectra obtained by UV-visible spectrophotometry on dispersions of composite materials A1, A2, B1 and B2 at 0.005% by mass in water.

represents the absorbance spectra obtained by UV-visible spectrophotometry on dispersions of composite materials C1, C2, C3 and C4 at 0.005% by mass in water.

represents the absorbance spectra obtained by UV-visible spectrophotometry on dispersions of composite materials D, E1, E2, F1 and F2 at 0.005% by mass in water.

represents the absorbance spectra obtained by UV-visible spectrophotometry on dispersions of composite materials G, H1 and H2 at 0.005% by mass in water.

represents the absorbance spectra obtained by UV-visible spectrophotometry on dispersions of composite materials I, J1 and J2 at 0.005% by mass in water.

represents the absorbance spectra obtained by UV-visible spectrophotometry on dispersions of composite materials K, L1 and L2 at 0.005% by mass in water.

represents the absorbance spectra obtained by UV-visible spectrophotometry on dispersions of composite materials M, N1, N2, O1 and O2 at 0.005% by mass in water.

represents the absorbance spectra obtained by UV-visible spectrophotometry on dispersions of composite materials P1, P2, Q1 and Q2 at 0.005% by mass in water.

represents the absorbance spectra obtained by UV-visible spectrophotometry on dispersions of composite materials S1, S2 and R at 0.005% by mass in a Water / Propylene glycol / Tween 20 mixture.

represents the absorbance spectrum obtained by UV-visible spectrophotometry on dispersions of composite material T at 0.005% by mass in a Water/Propylene glycol/Tween 20 mixture.

represents the absorbance spectra obtained by UV-visible spectrophotometry on dispersions of Alfa Aesar Bismutite, and of the composite material U at 0.005% by mass in water.

represents the absorbance spectrum obtained by UV-visible spectrophotometry on dispersions of composite materials V and W at 0.005% by mass in water.

represents the absorbance spectrum obtained by UV-visible spectrophotometry on dispersions of composite materials X, Y and Z at 0.005% by mass in water.

represents the absorbance spectrum obtained by UV-visible spectrophotometry on dispersions of AA composite material at 0.005% by mass in a Water/Propylene glycol/Tween 20 mixture.

represents the absorbance spectrum obtained by UV-visible spectrophotometry on dispersions of DD composite material at 0.005% by mass in water.

represents the absorbance spectra obtained by UV-visible spectrophotometry on dispersions of composite materials I and EE at t = 0 h and t = 48 h, and sodium lignosulfonate at 0.005% by mass in water.

represents the absorbance spectra obtained by UV-visible spectrophotometry on dispersions of composite materials D and FF at t = 0 h and t = 48 h, with T = 45 °C for t = 48 h at 0.005% by mass in water.

Detailed description

The invention relates to a composite material comprising a) at least one particle of bismuth oxycarbonate of formula (I) (BiO) _{2- x} (CO ₃ ), as well as its solvates such as hydrates, in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm; and b) at least one polymer.

Composite material

As previously stated, the composite material comprises a) at least one bismuth oxycarbonate particle and b) at least one polymer.

According to a particular embodiment, the mass ratio of bismuth oxycarbonate particle(s) a) to polymer(s) varies from 0.01 to 50, preferably from 0.2 to 15, more preferably from 0.3 to 10 and more preferably from 0.5 to 8.5.

By " average size " or " average dimension " is meant the number-average value of the dimensions of the composite material or particles. The dimensions of the composite materials or particles can be determined by transmission electron microscopy, for example using a Hitachi HT 7700 microscope, in particular at an acceleration voltage of 100 kV, by scanning electron microscopy, or from the measurement of the specific surface area by the BET method, or by means of a laser particle size analyzer. Preferably, the dimensions of the particles are determined by transmission electron microscopy, for example using a Hitachi HT 7700 microscope, in particular at an acceleration voltage of 100 kV, or by scanning electron microscopy.

Preferably, the measurement is carried out on the smallest individualized or individualizable objects.

The mean number value can be calculated by analyzing the obtained images using software, such as ImageJ software (C.A. Schneider, W.S. Rasband, K.W. Eliceiri, NIH Image to ImageJ: 25 years of image analysis, Nat. Methods. 9 (2012) 671–675).

The average dimension is chosen from the average length L, the average width l, the average thickness e, or the average diameter d.

By " the average size of the largest dimension " or " the largest average dimension " of composite materials or particles is meant the largest average dimension of a surface, such as a face, that can be measured between two diametrically opposite points of an individual particle. For the purposes of the present invention, this dimension may be defined as the maximum Feret diameter.

The “ length ” L of a composite material or particle is its largest dimension observable on a photograph taken in a direction perpendicular to the plane on which said composite material or particle rests.

The " width " l and " thickness " e of a composite material or particle are the lengths of the major and minor axes, respectively, of the smallest possible ellipse in which the median cross-section of said composite material or particle can be inscribed .

The " diameter " d of a composite material or particle is the largest dimension observable along a line passing through the center of a circle or sphere.

The composite materials according to the invention can be of various shapes and structures.

The composite materials according to the invention may in particular be spherical, cubic, platelet-like, cylindrical or tubular.

The shape of said composite materials will depend in particular on their preparation process and the operating conditions.

In particular, the composite materials according to the invention may be in the form of tubes, platelets, sheets, rods, spheres, flowers, pompoms, threads, filaments, fibers, needles, cubes or any of their mixtures.

The composite materials according to the invention can furthermore aggregate in the form of superstructures. For example, platelets, tubes and/or rods can aggregate in the form of spheres, flowers or even pompoms.

According to a particular embodiment, the composite materials according to the invention are in the form of spheres.

According to a particular embodiment, the composite materials according to the invention are in the form of tubes, plates and/or rods. Even more preferably, the composite materials according to the invention are in the form of plates and/or rods.

Composite materials in the form of plates or rods or tubes are therefore distinguished in particular from spherical, fibrous shapes, flowers, pompoms, threads, filaments, needles or cubes.

It is understood that the composite materials according to the invention can be used in the form of a mixture. In particular, the composite materials according to the invention can be used in a mixture in any proportion of platelets and/or rods and/or tubes.

Similarly, a composite material in the form of spheres can be composed of a polymer matrix and bismutite platelets, i.e. two morphologies represented in the same composite. It is also possible to complete the morphology of a film containing bimsutite particles by freeze-drying.

According to a preferred embodiment, the composite materials used according to the invention are mainly or exclusively in the form of platelets.

A composite material in the form of a " platelet " has a length greater than its width and a width greater than its thickness.

According to a preferred embodiment, the composite materials are mainly or exclusively in the form of rods.

A composite material in the form of a " rod " has a solid cylindrical shape and its length L is greater than its diameter d , or has a prism shape whose base is solid polygonal, preferably triangular or hexagonal, and the diameter d of the circle circumscribed to this polygonal base is less than the length L of the prism.

According to a preferred embodiment, the composite materials are mainly or exclusively in the form of tubes.

A composite material in the form of a “ tube ” has a hollow cylindrical shape and its length L is greater than its diameter d .

For the purposes of the present invention, the term " predominantly in the form of platelets/rods/tubes " means that at least 50% by number, in particular at least 70% by number, or even at least 90% by number of the composite materials are in the form of platelets/rods/tubes respectively.

The bismuth oxycarbonate particle(s) a) and the polymer(s) b) can be arranged in different ways within the composite material.

According to one embodiment, the composite material may have at least one core and at least one layer(s) coating surrounding said core.

Thus, they may comprise at least one coating in layer(s) surrounding a core chemically different from said coating.

The coating can be formed of one or more layers.

The core of the composite materials may consist of at least a) one or more particles of bismuth oxycarbonate of formula (I) (BiO) _{2- x} (CO ₃ ), as well as its solvates such as hydrates, in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm.

According to a particular embodiment, the core of the composite materials may consist of at least one polymer b).

The composite material may contain bismuth oxycarbonate particles a) as defined above in the core and/or in the layer(s) forming the coating.

According to a particular embodiment, the material contains at least one particle of bismuth oxycarbonate a) as defined above in the core.

According to another particular embodiment, the material contains bismuth oxycarbonate particles a) as defined above in the coating.

According to one embodiment, the polymer(s) b) may cover all or part of at least one particle of bismuth oxycarbonate a).

According to another embodiment, the polymer(s) b) may be covered in whole or in part by at least one particle of bismuth oxycarbonate a).

In particular, the mass ratio of bismuth oxycarbonate particle(s) a) to polymer(s) varies from 0.01 to 50, preferably from 0.2 to 15, more preferably from 0.3 to 10 and more preferably from 0.5 to 8.5.

According to a particular embodiment, the composite materials according to the invention contain at least one layer surrounding the core.

Thus, according to a particular embodiment, the composite materials according to the invention comprise a core comprising at least a) at least one particle of bismuth oxycarbonate of formula (I) (BiO) _{2- x} (CO ₃ ), as well as its solvates such as hydrates, in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm, said core being covered on the surface, continuously or discontinuously, by a coating comprising b) at least one polymer.

According to a first variant of the invention, the composite materials in accordance with the invention comprise a coating, also called a continuous shell or envelope, i.e. surrounding the entire surface of the core.

According to a second variant of the invention, the composite materials in accordance with the invention comprise a coating, also called a bark or envelope, which is discontinuous, i.e. discontinuously surrounding the surface of the core.

Preferably, from 10% to 90%, more particularly from 10% to 70%, and even more particularly from 30% to 50% of the surface of the core is covered by the coating.

According to one embodiment, the coating is a multilayer coating, that is to say comprising one or more internal layers and an external layer, in other words several superimposed layers for all or part of which each can be continuous or discontinuous.

In a multi-layer coating, the term " inner layer " means any layer that is not an outer layer. This may be the layer directly superimposed on the core or any intermediate layer between the core and the outer layer.

In a multi-layer coating, the term " outer layer " means the layer forming the last layer of the coating that is not contiguous with the core. The outer layer is separated from the core by at least one inner layer. The outer layer has no coating.

In a multilayer coating formed of two layers, the inner layer is the layer contiguous to the core and the outer layer is the layer contiguous to the inner layer and not contiguous to the core.

In a multilayer coating formed of more than two layers, the inner layers are the layer adjacent to the core and the intermediate layer(s) between the layer adjacent to the core and the outer layer.

The inner layer(s) forming the multi-layer coating of the composite material and the single outer layer of the composite material may be formed from the same or different compounds.

Each layer can consist of a single compound or a mixture of compounds.

The layer(s) may in particular extend concentrically relative to the core.

In particular, the composite materials according to the invention have a double layer surrounding the core, in other words an internal layer and an external layer.

According to a preferred embodiment, the composite materials according to the invention have at least one layer, preferably comprising at least b) at least one polymer.

According to a preferred embodiment, the composite materials according to the invention comprise:

- a core comprising at least a) at least one particle of bismuth oxycarbonate of formula (I) (BiO) _{2- x} (CO ₃ ), as well as its solvates such as hydrates, in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm, and

- at least one layer continuously or discontinuously surrounding said core and comprising b) at least one polymer.

Preferably, the composite materials according to the invention comprise:

- a core comprising at least a) at least one particle of bismuth oxycarbonate of formula (I) (BiO) _{2- x} (CO ₃ ), formula (I) as well as its solvates such as hydrates, in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm,

- a single layer contiguous to said core and comprising b) at least one polymer.

According to a particular embodiment, the composite materials according to the invention comprise:

- a core comprising at least a) at least one particle of bismuth oxycarbonate of formula (I) (BiO) _{2- x} (CO ₃ ), in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm, formula (I) as well as its solvates such as its hydrates,

- an internal layer contiguous to said core comprising at least one inorganic compound c) distinct from said bismuth oxycarbonate particles a),

- an outer layer contiguous to said inner layer and comprising b) at least one polymer.

According to a particular embodiment, the composite materials according to the invention comprise:

- a core comprising at least a) at least one particle of bismuth oxycarbonate of formula (I) (BiO) _{2- x} (CO ₃ ), in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm, formula (I) as well as its solvates such as its hydrates,

- an internal layer contiguous to said core comprising at least one inorganic compound c) distinct from said bismuth oxycarbonate particles a),

- an outer layer contiguous to said inner layer and comprising b) at least one polymer and optionally a) at least one particle of bismuth oxycarbonate of formula (I) (BiO) _{2- x} (CO ₃ ), in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm, formula (I) as well as its solvates such as its hydrates.

a) Bismuth oxycarbonate particles

The bismuth oxycarbonate particles a) according to the invention are of formula (I) (BiO) _{2- x} (CO ₃ as well as its solvates such as hydrates with -0.4 < x < 0.6. The value of x can in particular be determined by elemental analysis.

Preferably, x is equal to 0 and the empirical formula of bismuth oxycarbonate particles a) is (BiO) ₂ ( _CO3 ) than its solvates such as hydrates.

The bismuth oxycarbonate particles a) according to the invention may be crystallized or amorphous.

According to one form of the invention, the bismuth oxycarbonate particles a) are amorphous.

According to a preferred form of the invention, the bismuth oxycarbonate particles a) are crystallized.

It is understood that the bismuth oxycarbonate particles (a) may consist of a mixture of several bismuth oxycarbonate particles of different empirical formulas and/or different shapes.

Thus, bismuth oxycarbonate particles (a) may be a mixture of amorphous particles and crystalline particles.

By " crystallized " as used herein is meant that the atoms constituting the bismuth oxycarbonate particles are arranged in an orderly manner. In other words, the crystallized bismuth oxycarbonate particles are organized materials.

In contrast, " amorphous " particles are particles whose atoms are disordered. The atoms of such particles have no organization in the microscopic state.

Preferably, the crystallized particles required according to the invention have the crystalline phase of the natural ore bismutite, referred to as lamellar, and which has an alternation of [Bi ₂ O ₂ ] ²⁺ and [CO ₃ ] ^2- layers.

Such particles crystallize in an orthorhombic system of space group Imm2 .

The bismutite crystal structure of bismuth oxycarbonate can have the following lattice parameters: a = 3.865 Å; b = 3.862 Å; c = 13.675 Å and V _lattice = 0.204 nm ³ . This particular arrangement of atoms allows in particular the growth of anisotropic objects.

A particle is considered "anisotropic" when the elongation factor R between its length L and its thickness e , i.e. R = L / e , is greater than 2.

According to the invention, the largest average dimension of the crystallized or amorphous, preferably crystallized, particles of bismuth oxycarbonate a) of empirical formula (BiO) _{2- x} (CO ₃ ), in which -0.4 < x < 0.6 is less than 400 nm.

Preferably, the largest average dimension of said particles is less than or equal to 300 nm.

According to the invention, the bismuth oxycarbonate particles of empirical formula (BiO) _{2- x} (CO ₃ ), in which -0.4 < x < 0.6, can be in any form.

The shape of said particles will depend in particular on their preparation process and the operating conditions.

According to one embodiment, the particles a) are of identical morphology.

In particular, when the composition comprises particles a) of identical morphology, the composite material according to the invention consists of particles in the form of platelets or sheets or rods or spheres or flowers or pompoms or threads or filaments or fibers or needles, or cubes, preferably in the form of platelets or rods.

According to one embodiment, the particles a) are of different morphologies.

In particular, when the composite material comprises particles a) of different morphologies, the composite material according to the invention comprises one or more particles chosen from particles in the form of tubes, platelets, sheets, rods, spheres, flowers, pompoms, threads, filaments, fibers, needles, cubes or any of their mixtures.

The particles according to the invention can further aggregate in the form of superstructures. For example, platelets, tubes and/or rods can aggregate in the form of spheres, flowers or even pompoms.

According to a preferred embodiment, the particles according to the invention are in the form of platelets and/or rods.

Particles in the form of platelets or rods or tubes are therefore distinguished in particular from spherical, fibrous forms, flowers, pompoms, threads, filaments, needles or cubes.

It is understood that the particles according to the invention can be used in the form of a mixture. In particular, the particles according to the invention can be used in a mixture in any proportion of platelets and/or rods and/or tubes, in particular in a mixture in any proportion of platelets and/or rods.

According to a preferred embodiment, the particles used according to the invention are mainly or exclusively in the form of platelets.

A particle in the form of a " platelet " has a length greater than its width and a width greater than its thickness.

In particular, when in the form of platelets, bismuth oxycarbonate particles a) have:

- an average length L ranging from 15 to 300 nm, in particular ranging from 30 to 250 nm, preferably ranging from 50 to 200 nm, more preferably ranging from 70 to 150 nm;

- an average width l ranging from 10 to 250 nm, in particular ranging from 20 to 200 nm, preferably ranging from 30 to 150 nm, more preferably ranging from 50 to 120 nm;

- an average thickness e ranging from 2 to 120 nm, in particular ranging from 5 to 100 nm, preferably ranging from 10 to 80 nm, more preferably ranging from 20 to 50 nm; and

- with e < l < L .

According to one embodiment, the bismuth oxycarbonate particles are predominantly or exclusively in the form of rods or comprise particles in the form of rods.

A particle in the form of a " rod " has a solid cylindrical shape and its length L is greater than its diameter d , or has a prism shape whose base is solid polygonal, preferably triangular or hexagonal, and the diameter d of the circle circumscribed to this polygonal base is less than the length L of the prism.

In particular, when they are in the form of rods, whether cylindrical or prismatic, bismuth oxycarbonate particles have:

- an average length L ranging from 30 to 300 nm, in particular ranging from 50 to 250 nm, preferably ranging from 70 to 230 nm, more preferably ranging from 70 to 140 nm;

- an average diameter d ranging from 15 to 150 nm, in particular ranging from 20 to 130 nm, preferably ranging from 25 to 120 nm, more preferably ranging from 25 to 100 nm, and even more preferably ranging from 25 to 60 nm, and

- with L > d .

According to one embodiment, the bismuth oxycarbonate particles of the invention contain particles in the form of tubes.

A particle in the form of a " tube " has a hollow cylindrical shape and its length L is greater than its diameter d .

In particular, when in the form of tubes, bismuth oxycarbonate particles have:

- an average length L ranging from 10 to 300 nm, in particular ranging from 20 to 250 nm, preferably ranging from 40 to 200 nm, more preferably ranging from 60 to 200 nm;

- an average diameter d ranging from 2 to 30 nm, in particular ranging from 3 to 20 nm, and preferably ranging from 5 to 15 nm; and

- with L > d .

For the purposes of the present invention, the term " predominantly in the form of platelets/rods " means that at least 50% by number, in particular at least 70% by number, or even at least 90% by number of the particles are in the form of platelets/rods respectively.

Particle doping a)

According to a particular embodiment, the bismuth oxycarbonate particles a) can be doped.

In particular, bismuth oxycarbonate particles can be doped with one or more chemical elements capable of being inserted into the structure or of partially replacing elements already present.

The particles can be doped via substitutions of all or part of the cations and/or all or part of the anions.

According to a particular embodiment, the doping partly concerns cations in insertion or substitution of bismuth within the limit of 20% of the bismuth composition.

According to this variant, the doping rate varies in particular from 0.005% to 15%, preferably from 0.05% to 12%, more preferably from 0.1% to 10%, and even more preferably from 0.5% to 6%.

In particular, the bismuth oxycarbonate particles may be doped with cations derived from elements selected from aluminum (Al), silicon (Si), scandium (Sc), titanium (Ti), vanadium (V), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), silver (Ag), indium (In), lanthanum (La), cerium (Ce), tantalum (Ta), tungsten (W) and/or gold (Au).

Preferably, the bismuth oxycarbonate particles may be doped with cations from elements selected from titanium, vanadium, manganese, iron, copper, zinc, lanthanum, and/or cerium, more preferably from manganese, iron and/or cerium, and even more preferably from manganese or iron.

According to an alternative embodiment, the bismuth oxycarbonate particles are doped with cations derived from manganese, and the doping rate varies in particular from 0.5% to 2%.

According to another embodiment, the bismuth oxycarbonate particles are doped with cations derived from iron, and the doping rate varies in particular from 0.5% to 2%.

According to another particular embodiment, the doping concerns in part or in total anions in insertion or in substitution of the carbonate group within the limit of 20% of the carbonate composition.

According to this variant, the doping rate varies in particular from 0.001% to 1%, preferably from 0.002% to 0.5%, more preferably from 0.003% to 0.2%, and even more preferably from 0.005% to 0.1%.

In particular, the bismuth oxycarbonate particles may be doped with anions derived from elements selected from fluorine (F), sulfur (S), chlorine (Cl), bromine (Br), iodine (I), and/or with polyatomic anions, in particular selected from sulfate ion (SO ₄ ^2- ), sulfonate ion (S(=O) ₂ -O ^- ), sulfite ion (SO ₃ ^2- ), phosphate ion (PO ₄ ^3- ) and/or iodate ion (IO ₃ ^- ).

Preferably, the bismuth oxycarbonate particles may be doped with S^2-,
SO₃ ^2-, SO₄ ^2-, Cl^- and/or I^-, more preferably with SO₃ ^2-, SO₄ ^2-and/or Cl^-, and more preferably with Cl^-or SO₄ ^2-.

According to an alternative embodiment, the bismuth oxycarbonate particles are doped with anions derived from chlorine, and the doping rate varies in particular from 0.01% to 0.1%.

According to another embodiment, the bismuth oxycarbonate particles are doped with anions derived from iodine, and the doping rate varies in particular from 0.003% to 0.01%.

According to another embodiment, the bismuth oxycarbonate particles are doped with the sulfate ion, and the doping rate varies in particular from 0.005% to 0.1%.

According to another embodiment variant, the bismuth oxycarbonate particles are doped with cations preferably from elements chosen from titanium, vanadium, manganese, iron, copper, zinc, lanthanum, and/or cerium, more preferably chosen from manganese, iron and/or cerium, and even more preferably chosen from manganese or iron, and with anions preferably from elements chosen from fluorine (F), sulfur (S), chlorine (Cl), bromine (Br), iodine (I), and/or with polyatomic anions, in particular chosen from the sulfate ion (SO₄ ^2-), the sulfonate ion (S(=O)₂-O^-), the sulfite ion (SO₃ ^2-), the phosphate ion (PO₄ ^3-) and/or the iodate ion (IO₃ ^-), more preferably with S^2-, SO₃ ^2-, SO₄ ^2-, Cl^- and/or I^-, even more preferably with SO₃ ^2-, SO₄ ^2-and/or Cl^-, and particularly preferably with Cl^-, I^-or SO₄ ^2-.

According to a preferred embodiment, the bismuth oxycarbonate particles required according to the invention are undoped.

According to another preferred embodiment, the bismuth oxycarbonate particles required according to the invention are doped.

According to another preferred embodiment, the bismuth oxycarbonate particles required according to the invention are a mixture of doped particles and undoped particles.

Particle preparation process d ’ bismuth oxycarbonate a)

The bismuth oxycarbonate particles a) can be obtained by any preparation process known to those skilled in the art.

For example, the synthesis of bismuth oxycarbonate particles is described in the article by Ni et al. (Fabrication, modification and application of (BiO) ₂ CO ₃ -based photocatalysts: A review, Applied Surface Science, 365, 2016, 314–335).

In particular, bismuth oxycarbonate particles can be prepared solvothermally, electrochemically, by co-precipitation, or by reflux, and preferably solvothermally or by reflux.

According to a first embodiment, the bismuth oxycarbonate particles are obtained by solvothermal means, in particular from bismuth nitrate and various carbonating agents such as sodium carbonate, ammonium carbonate or urea, in a polar protic solvent in the presence of polyols. Such a synthesis makes it possible to obtain bismuth oxycarbonate particles in the form of platelets and/or rods, the largest dimension of which varies from 50 to 300 nm.

The synthesis of particles by solvothermal means is notably described in the articles of Cheng, G. et al. (Shape-controlled solvothermal synthesis of bismuth subcarbonate nanomaterials, J. Solid State Chem. 183, 1878–1883 (2010)); Ruan, M. M. et al. (Facile Green Synthesis of Highly Monodisperse Bismuth Subcarbonate Micropompons Self-assembled by Nanosheets: Improved Photocatalytic Performance, Acta Physico-Chimica Sinica, 33, 2017, 1033–1042); Quin et al. (Template‐Free Fabrication of Bi ₂ O ₃ and (BiO) ₂ CO ₃ Nanotubes and Their Application in Water Treatment, Chem. Eur. J., 18, 2012, 16491–16497); Cheng, G. et al. (Shape-controlled solvothermal synthesis of bismuth subcarbonate nanomaterials, J. Solid State Chem., 183, 2010, 1878–1883); Liu, YY et al. (Preparation, electronic structure, and photocatalytic properties of Bi ₂ O ₂ CO ₃ nanosheet, Appl. Surf. Sci., 257, 2010, 172–175); Zheng et al. (Synthetic Bi ₂ O ₂ CO ₃ nanostructures: Novel photocatalyst with controlled special surface exposed, Journal of Molecular Catalysis A: Chemical, 2010, 317 (1-2), 34-40); Liu, SQ et al. (The effects of citrate ion on morphology and photocatalytic activity of flower-like Bi ₂ O ₂ CO ₃ , Ceram. Int., 40, 2014, 2343–2348); or Chen, R. et al . (Bismuth subcarbonate nanoparticles fabricated by water-in-oil microemulsion-assisted hydrothermal process exhibit anti-Helicobacterpylori properties, Mater. Res. Bull., 45, 2010, 654–658).

The synthesis of particles by electrochemical route is notably described in the article by Hu, Y. et al. (Simple hydrolysis route to synthesize Bi ₂ O ₂ CO ₃ nanoplate from Bi nanopowder and its photocatalytic application, Materials Letters, 170, 2016, 72–75).

The synthesis of particles by co-precipitation is notably described in the article by Chen, XY et al. (Controlled synthesis of bismuth oxo nanoscalecrystals (BiOCl, Bi ₁₂ O ₁₇ Cl ₂ , α-Bi ₂ O ₃ , and (BiO) ₂ CO ₃ ) by solution-phase methods, J. Solid State Chem., 180, 2007, 2510–2516).

The synthesis of particles by reflux is notably described in the article by Chen et al. (Fabrication of bismuth subcarbonate nanotube arrays from bismuth citrate, Chem. Commun., 2006, 2265–2267).

According to a preferred embodiment, the bismuth oxycarbonate particles required according to the invention are obtained solvothermally, for example according to the method described by Cheng et al. , or at reflux, for example according to the method described by Chen et al..

According to a preferred embodiment, the bismuth oxycarbonate particles required according to the invention are obtained by a preparation process using one or more bismuth (III) complexes, one or more carbonating agents, one or more polyols and optionally one or more polar solvents, distinct from the polyols.

When the particles used according to the invention are doped, one or more additional reagents including doping elements may be added.

In particular, the bismuth(III) complex(es) is(are) chosen from bismuth nitrate and its hydrated forms, bismuth citrate and its hydrated forms, bismuth sulfate and its hydrated forms and bismuth chloride and its hydrated forms.

Bismuth(III) complex(es) can also be obtained from bismuth minerals, such as elemental bismuth and/or bismuth oxide and/or bismuth sulfide.

Preferably, the bismuth(III) complex(es) is(are) bismuth(III) nitrate and its hydrated forms of formula Bi( _NO3 ) ₃ · xH2O , and preferably is bismuth nitrate pentahydrate of formula Bi( _NO3 ) ₃ · _{5H2O .}

In particular, the carbonating agent(s) is (are) selected from Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Rb ₂ CO ₃ , Cs ₂ CO ₃ , (NH ₄ ) ₂ CO ₃ , LiHCO ₃ , NaHCO ₃ , KHCO ₃ , RbHCO ₃ , CsHCO ₃ , (NH ₄ ) HCO ₃ , urea (NH ₂ ) ₂ CO and urea derivatives, CO ₂ , preferably from Na ₂ CO ₃ , K ₂ CO ₃ , (NH ₂ ) ₂ CO, (NH ₄ ) ₂ CO ₃ , and more preferably from (NH ₂ ) ₂ CO and/or (NH ₄ ) ₂ CO ₃ .

Polyols are compounds having several hydroxyl functions. They can in particular be chosen from glycols, in particular ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol; short or long polymers of glycols, for example polyethylene glycol, polypropylene glycol, polybutylene glycol; glycerol and its derivatives; or for example sugars, in particular glucose, fructose, sucrose, xylitol, mannitol, such as D-mannitol, sorbitol or maltitol.

According to one embodiment, the bismuth oxycarbonate particles required according to the invention are obtained by a preparation process using a polyol or a mixture of polyols.

According to a first embodiment variant, the polyol(s) may also be used as a solvent. The bismuth oxycarbonate particles may then be obtained, for example, according to the process described below.

A solution A is formed from the dissolution of the bismuth(III) complex, preferably at a concentration of 0.001 to 0.5 M, in the polyol or polyol mixture. A solution B is formed by the partial or complete dissolution of the carbonating agent, preferably from 1 to 100 equivalents relative to bismuth, in the polyol or polyol mixture or in a polyol or polyol mixture different from that(those) used in solution A.

In case of doping by a cation, the doping agent is preferably integrated into solution A. In case of doping by an anion, the doping agent is preferably integrated into solution B.

In case of doping with one or more cation(s) and/or one or more anion(s), the cationic doping agent(s) is/are preferably integrated into solution A and the anionic doping agent(s) is/are preferably integrated into solution B. Solution A is then added at room temperature to solution B. If the polyol or polyol mixture is not liquid at room temperature, all solids are mixed.

The resulting mixture is then heated to between 90 and 250 °C for a reaction time of between 10 minutes and 48 hours. If the desired reaction temperature is greater than or equal to the boiling point of the solvent, a solvothermal synthesis is carried out using an autoclave.

Preferably, the reaction temperature is between 95°C and 200°C and the reaction time is between 1 and 24 hours, and more preferably the reaction temperature is between 100°C and 180°C and the reaction time is between 2 and 16 hours.

The particles obtained are isolated from the reaction medium by centrifugation and washed by successive cycles of dispersion and centrifugation.

After drying under vacuum at a temperature between 40°C and 60°C, a white powder is obtained.

In the case where the polyol(s) are used as solvents, the bismuth oxycarbonate particles obtained are in the form of platelets, preferably with an average thickness e of between 2 and 15 nm, and/or in the form of tubes.

According to another embodiment, the polyol(s) are used only as additives, and not as a solvent. The bismuth oxycarbonate particles can then be obtained, for example, according to the process described below.

A solution A is formed from the dissolution of the bismuth complex, preferably at a concentration of 0.001 to 0.5 M, and the polyol(s) preferably at a total concentration of polyols, preferably 0.01 to 5 M, in a solvent, preferably polar. A solution B is formed by the partial or complete dissolution of the carbonating agent, preferably 1 to 100 equivalents relative to the bismuth complex, in the polar solvent identical or different (miscible with the solvent of A) from that of solution A, preferably identical.

In case of doping by a cation, the doping agent is preferably integrated into solution A. In case of doping by an anion, the doping agent is preferably integrated into solution B.

In the case of doping by one or more cation(s) and/or by one or more anion(s), the cationic doping agent(s) is/are preferably integrated into solution A and the anionic doping agent(s) is/are preferably integrated into solution B.

Solution A is then added at room temperature to solution B. The resulting mixture is then heated between 90 °C and 250 °C for 10 minutes to 48 hours. If the desired reaction temperature is greater than or equal to the boiling point of the solvent, a solvothermal synthesis is carried out using an autoclave.

Preferably, the reaction temperature is between 90°C and 150°C and the reaction time is between 4 and 16 hours.

The particles obtained are isolated from the reaction medium by centrifugation and washed by successive cycles of dispersion and centrifugation.

After drying under vacuum at a temperature between 40°C and 60°C, a white powder is obtained.

When the polyol(s) are used solely as additives, they may in particular be chosen from ethylene glycol, propylene glycol, glycerol and/or a sugar, preferably a sugar, more preferably D-mannitol.

According to this variant, the synthesis process further uses a solvent distinct from the polyols, or a mixture of solvents distinct from the polyols. In particular, the solvent or the mixture of solvents is chosen from polar solvents, preferably from polar and protic solvents, such as water; C ₁ -C ₆ alcohols such as ethanol or isopropanol; and mixtures thereof, and even more preferably the solvent is water.

In particular, when the polyol(s) are chosen solely as additives and water as solvent, the bismuth oxycarbonate particles obtained are preferably in the form of platelets and/or in the form of rods.

Polymer b)

The composite materials according to the invention comprise at least one polymer b).

The polymer(s) b) are natural and/or synthetic, hydrophilic and/or hydrophobic and/or amphiphilic, anionic and/or cationic and/or zwitterionic and/or non-ionic (or so-called “neutral”). Preferably the polymer(s) b) is (are) non-ionic, anionic or cationic, more preferably non-ionic or anionic.

In particular, the polymer(s) b) are chosen from polymers having a molecular weight of between 1,000 and 20,000,000 Da, preferably between 5,000 and 10,000,000 Da and even more preferably between 7,000 and 3,000,000 Da.

The polymer(s) b) are in crosslinked and/or non-crosslinked form, preferably non-crosslinked.

The polymer(s) b) may be silicone or non-silicone.

According to a particular embodiment, the polymer(s) b) are or comprise at least one silicone polymer.

Examples of silicone polymers b) include dimethicone copolyols, in particular the mixture of cyclomethicone and dimethicone copolyol, sold in particular under the name "DC 5225 C ^® " by the company Dow Corning, and alkyl-dimethicone copolyols, in particular Laurylmethicone copolyol, sold in particular under the name "Dow Corning 5200 Formulation Aid" by the company Dow Corning, Cetyl dimethicone copolyol and the mixture of cetyl dimethicone copolyol, polyglycerol isostearate (4 moles) and hexyl laurate.

According to a preferred embodiment, the polymer(s) b) do not contain silicon atoms.

According to a preferred embodiment, the mass by weight Mw of the polymers b) is greater than or equal to 2000.

By " anionic polymer " is meant a polymer containing one or more anionic groups, in particular carboxyls, carboxylates, sulfates, sulfonic acids, sulfonates, phosphates, phosphonic acids, phosphonates, preferably chosen from carboxylates and/or sulfonates and/or sulfates. The anionic derivatives can be salified in the form of salts of alkali or alkaline-earth metals, preferably sodium or calcium.

By " cationic polymer " is meant a polymer containing one or more cationic groups, charged regardless of the pH, or cationizable. Preferably, the cationic polymers b) carry amino groups.

By " nonionic polymer " is meant a polymer which does not carry charged groups or which may be charged by varying the pH.

In particular, the polymer(s) b) may be chosen from polyphenols and their salts, polyphenol sulfonates and their salts, polysaccharides and their salts, polyacids and their salts, polyols, polyamides, polyamines and their salts, polyesters, polyhydroxy alkanoates, polyureas, polyurethanes, polyethers, polyethylenes, polypropylenes, polystyrenes, proteins, and/or their copolymers and/or their mixtures.

The polymer(s) b) are cyclic or acyclic (containing no cycle in their structure).

The cyclic polymer(s) b) may be aromatic (contain at least one aromatic ring) or non-aromatic.

Examples of b) cyclic aromatic polymers include lignosulfonic acid, lignosulfonates, polystyrene sulfonics, polystyrene sulfonates, anionic polyanethol derivatives, in particular polyanethol sulfonates, and mixtures thereof.

According to a particular embodiment, said polymer(s) b) are chosen from polystyrene sulfonic acid, polystyrene sulfonate, in particular polystyrene sulfonates of alkali or alkaline earth metal salts, in particular sodium or calcium.

According to one embodiment, said polymer(s) b) are chosen from lignosulfonic acids or its lignosulfonate salts of alkali or alkaline earth metals, in particular sodium or calcium.

According to one embodiment, said polymer(s) b) are chosen from anionic polyanethole derivatives, in particular polyanethole sulfonates of alkali or alkaline earth metals, in particular sodium or calcium, in particular sodium.

Preferably, the non-aromatic cyclic polymers b) are chosen from polysaccharides, these polysaccharides being able to be anionic, cationic or non-ionic.

Preferably, the polymer(s) b) are chosen from hydrophilic and/or lipophilic and/or amphiphilic and anionic and/or cationic, and/or neutral natural polysaccharides.

More preferably, the polymer(s) used are natural hydrophilic and/or lipophilic and/or amphiphilic and anionic and/or cationic and/or neutral polysaccharides and in particular natural hydrophilic anionic and/or cationic and/or neutral polysaccharides. More preferably, the polymer(s) used are neutral or anionic polysaccharides.

As a representative and non-limiting example of these polysaccharides, mention may in particular be made of carrageenans, chitosan, dextran sulfates, (di)starch phosphates, pullulans and their forms esterified (or acetylated) by a carboxylic acid preferably comprising from 1 to 30 carbon atoms, more particularly from 8 to 20 carbon atoms, such as pullulan myristoyl and ulvan.

According to a particular embodiment, the polymer(s) b) of the invention represent a mixture of polymers b), one of which is a polysaccharide or one of its salts, its α or β anomers, its optical isomers of L or D configuration and its solvates, such as hydrates.

According to a particular embodiment, the polymer(s) b) of the invention represent a single polysaccharide or one of its salts, its α or β anomers, its optical isomers of L or D configuration and their solvates, such as hydrates.

In particular, the non-aromatic cyclic polymers b) are chosen from anionic polysaccharides are chosen from sulfated polysaccharides, phosphated polysaccharides and carboxylate polysaccharides.

The polysaccharide can be optionally acetylated. The acetylation rate can range from 1% to 40% by weight (weight rate of acetyl units relative to the total weight of the polymer).

According to a preferred embodiment, the polymer b) is chosen from polysaccharides having a weight average molecular weight ranging from 1,000 to 20,000,000 Da, preferably from 5,000 to 10,000,000 Da and even more preferably from 7,000 to 3,000,000 Da.

Phosphated polysaccharides include phosphated starches such as hydroxypropyl corn distarch phosphate.

Among the sulfated polysaccharides, mention may be made of ulvans, dextran sulfates, carrageenans, in particular lambda carrageenan, fucoidans, ulvans, dextran sulfates, and their mixtures.

Advantageously, the sulfation rate of the polysaccharides can range from 1% to 90% by weight, relative to the weight of polysaccharide(s). Preferably, this sulfation rate can range from 2% to 85% by weight.

In particular, the sulfated polysaccharides b) may also be chosen from ulvans, which are sulfated polysaccharides derived from algae, in particular red or green algae.

Ulvans can be obtained from many species of Ulva including Ulva lactuca, Ulva rigida, Ulva armoricana, Ulva rotundata and Ulvaria obscura, as well as several species of Enteromorpha, particularly Enteromorpha compressa, Enteromorpha intestinalis and Enteromorpha ramulosa.

Ulvans consist primarily of rhamnose, glucuronic acid, glucose, galactose, and xylose and also include sulfate groups. They may also include varying amounts of galacturonic acid, iduronic acid, and mannose.

Ulvans generally have a polysaccharide sulfation rate ranging from 1% to 30% by weight, relative to the weight of the polysaccharide, and more particularly from 10% to 20% by weight.

The relative proportion of sugars in ulvans varies depending on the location of the ulva harvest, the species and also the time of harvest in the year. For the extraction of ulvans from ulva, one can refer to the extraction processes described in Carbohydrate Research 274 (1995) 251-261 or in Hydrobiologia 326/327;473-480,1996.

According to a particular embodiment, the polymer(s) b) are or contain at least one ulvan.

In particular, the sulfated polysaccharides b) may also be chosen from dextrans sulfates derived from dextran.

Dextran is a complex branched glucan (polysaccharide derived from the condensation of glucose), originally derived from wine. The IUPAC defines dextrans as “branched poly-α-d-glucosides of microbial origin whose glycosidic bonds are predominantly C-1 → C-6”. Dextrans chains are of variable lengths (from 3 to 2000 kilodaltons).

The main chain of the polymer consists of α-1,6 glycosidic bonds between the glucose monomers, with branches of α-1,3 bonds. This characteristic branching distinguishes a dextran from a dextrin, which is a straight-chain glucose polymer linked by α-1,4 or α-1,6 bonds.

In particular, we can use dextran sulfate sold under the trade name Dextran sulfate 10 sodium salt CG, by the company PK chemicals.

Among the carboxylate polysaccharides b), we can cite alginates.

Alginates are obtained from brown algae such as kelp or fucus. Alginates are preferably sodium alginates or calcium alginates.

Alginates are polysaccharides derived from mannuronate or mannuronic acid, some of which are possibly acetylated, and guluronate or guluronic acid. The bond is of the beta 1-4 type.

According to a particular embodiment, the polymer(s) b) of the invention are chosen from non-ionic polymers, in particular non-ionic polysaccharides.

Examples of non-ionic polysaccharides include starches, particularly pullulan.

According to one embodiment, the polymer(s) b) according to the invention are chosen from nonionic polymers, in particular nonionic polysaccharides and more particularly polysaccharides modified by the presence of at least one aliphatic hydrocarbon chain, cyclic or non-cyclic, linear or branched, saturated or unsaturated, aromatic or not, comprising from 2 to 30 carbon atoms optionally substituted by one or more atoms or groups a) halogen, such as chlorine or bromine, b) (hetero)aryl, such as phenyl or furyl, c) (hetero)cycloalkyl, such as anhydride, epoxide or dithiolane, d) RX with R representing a group chosen from i) cycloalkyl such as cyclohexyl, and/or ii) (di)alkylamino and/or optionally interrupted by one or more heteroatoms or groups chosen from a') heteroatoms, such as O, S, N(Ra), and Si(Rb)(Rc), b') S(O)r, (thio)carbonyl, c') or the combinations of a') with b'), such as (thio)ester, (thio)amide, (thio)urea, sulfonamide with r being 1 or 2, Ra representing a hydrogen atom, or a (C ₁ -C ₄ )alkyl group, or aryl(C ₁ -C ₄ )alkyl, such as benzyl, preferably Ra represents a hydrogen atom, Rb and Rc, identical or different, represent a (C ₁ -C ₄ )alkyl or (C ₁ -C ₄ )alkoxy group.

Modified polysaccharides include those obtained from native gums, such as those from tree or berry exudates, algae, seeds or tubers, fungi, bacteria, animal organisms, plants, which have been modified by physical, chemical or enzymatic reactions.

In particular, native gums can be chosen from:

- gum arabic (branched polysaccharide of galactose, arabinose, rhamnose and glucuronic acid);

- gum ghatti (polymer derived from arabinose, galactose, mannose, xylose and glucuronic acid);

- karaya gum (polymer derived from galacturonic acid, galactose, rhamnose and glucuronic acid);

- gum tragacanth (or tragacanth) (polymer of galacturonic acid, galactose, fucose, xylose and arabinose);

- agar (polymer derived from galactose and anhydrogalactose);

- alginates (polymers of mannuronic acid and glucuronic acid);

- carrageenans and furcellerans (polymers of galactose sulfate and anhydrogalactose sulfate);

- guar gum (polymer of mannose and galactose);

- carob gum (polymer of mannose and galactose);

- fenugreek gum (polymer of mannose and galactose);

- tamarind gum (polymer of galactose, xylose and glucose);

- konjac gum (polymer of glucose and mannose);

- xanthan gum (polymer of glucose, mannose acetate, mannose/pyruvic acid and glucuronic acid) or dehydroxanthan gum;

- gellan gum (polymer of partially acylated glucose, rhamnose and glucuronic acid);

- scleroglucan gum (glucose polymer);

- cellulose (glucose polymer);

- starch (glucose polymer);

- inulin; and

- pectin.

In particular, the modified polysaccharides are derived from: i) gum arabic; ii) gum ghatti; iii) gum karaya; iv) gum tragacanth; v) agar; vi) alginates; vii) carrageenans and furcellerans; viii) guar gum; ix) locust bean gum; x) fenugreek gum; xi) tamarind gum; xii) konjac gum; xiii) xanthan gum or dehydroxanthan gum; xiv) gellan gum; xv) scleroglucan gum; xvi) cellulose; xvii) starch; xviii) inulin; and xix) pectin.

Starch molecules xvii) can have a botanical origin from cereals or tubers. Thus, starches are for example chosen from corn, rice, cassava, barley, potato, wheat, sorghum, pea starches.

Starches can be modified chemically or physically, in particular by one or more of the following reactions: pregelatinization, oxidation, crosslinking, esterification, etherification, amidation, heat treatments.

Nonionic modified polysaccharides can be modified physically or chemically. Physical treatment includes, for example, temperature.

Chemical treatments include esterification, etherification, amidation, oxidation, metathesis and addition reactions.

According to a particular embodiment, the modified polysaccharides are polysaccharide ethers called alkyl polysaccharides whose alkyl radical comprises between 2 and 30 carbon atoms, preferably between 2 and 10 carbon atoms, more preferably between 2 and 6 carbon atoms.

Preferably, the alkyl polysaccharides according to the invention are derived from cellulose or guar or their mixtures.

According to a particular embodiment, the modified polysaccharides are alkylcelluloses whose linear or branched alkyl residue comprises between 1 to 10 carbon atoms, in particular between 2 and 6 carbon atoms, preferably between 2 and 3 carbon atoms.

Alkylcellulose is an alkyl ether of cellulose comprising a chain consisting of β-anhydroglucose units linked together by acetal bonds. Each anhydroglucose unit has three replaceable hydroxyl groups, all or part of these hydroxyl groups being able to react according to the following reaction:

Cell-OM + R-Hal Cell-OR + MHal

with Hal representing a halogen, such as Cl, with M representing a cationic counterion, such as alkali metal Na or K, or alkaline earth metal, preferably an alkali metal, such as Na, Cell representing a polysaccharide radical, such as cellulose, where R represents a linear or branched alkyl group, comprising from 1 to 10 carbon atoms, preferably between 2 and 3 carbon atoms, such as methyl or ethyl, and MHal the salt generated such as sodium chloride.

Advantageously, the alkylcellulose is chosen from ethylcellulose and propylcellulose.

According to a particular embodiment, the polysaccharide ethers are alkyl guars, in other words guar gums viii) modified by substitution of hydroxy hydrogen by a linear or branched alkyl group, comprising between 1 to 10 carbon atoms, in particular between 2 and 6 carbon atoms, preferably between 2 and 3 carbon atoms, such as 2 carbon atoms.

The alkyl guar polymers used according to the invention are preferably ethyl guar.

Ethyl guar is known by the INCI name: C1-C5 alkyl galactomannan.

Alkylated guar gums (with _C1 - _C6 alkyl group), including ethyl guar, are described in particular in patent application EP 708114 and document RD9537807 (October 1995), as well as their preparation process.

According to a particular embodiment, the modified polysaccharides are polysaccharide esters, in particular esters obtained by reaction between at least one polysaccharide such as dextrin with at least one linear or branched saturated or unsaturated acid comprising from 2 to 30 carbon atoms, in particular from 10 to 30 carbon atoms.

According to a particular embodiment of the invention, the modified polysaccharide(s) are chosen from polysaccharide mono- or polyalkyl esters.

Among the mono or polyalkyl esters of saccharide or polysaccharide suitable for implementing the invention, mention may be made of alkyl or polyalkyl esters of dextrin or inulin.

This may include in particular a mono- or poly-ester of dextrin (dextrin being derived from starch xvii) and at least one fatty acid (such as R-C(O)-OH) and in particular corresponding to the following formula (XVIII):

formula (XVIII) in which:

- n is an integer greater than or equal to 2, preferably ranging from 3 to 200, in particular ranging from 20 to 150, and in particular ranging from 25 to 50,

- R ₁ , R ₂ and R ₃ , identical or different, are chosen from hydrogen or an acyl group (RC(O)-) in which the radical R is a hydrocarbon group, linear or branched, saturated or unsaturated, having from 7 to 29, in particular from 7 to 21, in particular from 11 to 19, more particularly from 13 to 17, or even 15, carbon atoms, it being understood that at least one of said radicals R ₁ , R ₂ or R ₃ is other than hydrogen.

In particular, R ₁ , R ₂ and R ₃ represent a hydrogen atom or an acyl group (RC(O)-) in which R is a hydrocarbon radical as defined above, provided that at least two of said radicals R ₁ , R ₂ or R ₃ are other than hydrogen.

The set of radicals R ₁ , R ₂ and R ₃ can represent an identical or different acyl group (RC(O)), and the acyl groups are notably identical.

In particular, n previously exposed advantageously varies from 25 to 50, in particular is equal to 38 in the general formula of the saccharide ester usable in the present invention.

In particular, when the radicals R ₁ , R ₂ and/or R ₃ , which are identical or different, represent an acyl group (RC(O)), derived from fatty carboxylic acid RC(O)OH preferably chosen from caprylic, capric, lauric, myristic, palmitic, stearic, arachic, behenic, isobutyric, isovaleric, 2-ethylbutyric, ethylmethylacetic, isoheptanoic, 2-ethylhexanoic, isononanoic, isodecanoic, isotridecanoic, isomyristic, isopalmitic, isostearic, isoaracic, isohexanoic, decenoic, dodecenoic, tetradecenoic, myristoleic, hexadecenoic, palmitoleic, oleic, elaidic, asclepinic, gondoleic, eicosenoic acids, sorbic, linoleic, linolenic, punicic, stearidonic, arachidonic, stearolic, and mixtures thereof.

Preferably, at least one dextrin palmitate is used as the ester of dextrin and fatty acid(s). This can be used alone or in a mixture with other esters.

Preferably, the dextrin and fatty acid ester has a degree of substitution less than or equal to 2.5 based on a glucose unit, in particular varying from 1.5 to 2.5, preferably from 2 to 2.5. The weight-average molecular weight of the dextrin ester may be in particular from 10,000 to 150,000 Da, in particular from 12,000 to 100,000 Da, and even from 15,000 to 80,000 Da.

Preferably, the modified polysaccharide(s) of the invention are dextrin esters, more preferably dextrin palmitates.

Dextrin esters, particularly dextrin palmitates, are commercially available under the name Rheopearl KL2 ^® , MKL2 ^® , TL ^® or KL ^® from Chiba Flour.

According to a particular embodiment, the modified polysaccharide is a modified dextrin, preferably a dextrin ester, more particularly an ester of dextrin and saturated or unsaturated, linear or branched C ₁₂ -C ₂₄ fatty acid.

Preferably, the dextrin ester is chosen from esters of saturated or unsaturated, linear or branched C ₁₄ -C ₂₄ fatty acids, such as myristic acid, palmitic acid or their mixture.

According to a particular embodiment, the dextrin ester is chosen from dextrin palmitate such as Rheopearl KL2 ^® and Rheopearl TL2 ^® , marketed by Chiba Flour, dextrin myristate, such as that marketed under the reference Rheopearl MKL2 ^® by Chiba Flour, dextrin palmitate/ethylhexanoate marketed under the reference Rheopearl TT2 ^® , dextrin palmitate/hexyldecanoate marketed under the reference Rheopearl WX, or mixtures thereof.

According to a particular embodiment, the modified polysaccharide is a modified inulin, preferably an inulin ester, more particularly an ester of inulin and saturated or unsaturated, linear or branched C ₁₂ -C ₂₄ fatty acid.

Preferably, the inulin ester is chosen from esters of saturated or unsaturated, linear or branched C ₁₄ -C ₂₄ fatty acids, such as myristic acid, palmitic acid, stearic acid, preferably stearic acid, or mixtures thereof.

According to a particular embodiment, the inulin ester is a stearoyl inulin, such as the references Rheopearl ISK2 ^® and Rheopearl ISL2 ^® , marketed by Chiba Flour, or their mixtures.

According to one embodiment, the modified polysaccharide is a modified cellulose, preferably a cellulose ester, more particularly an ester of cellulose and a saturated or unsaturated, linear or branched C ₂ -C ₂₄ acid.

Preferably, the cellulose ester is chosen from esters of saturated or unsaturated, linear or branched _C2 - _C10 , preferably _C2 - _C6 , in particular _C2 - _C4 , acids, such as acetic acid, butyric acid or their mixture.

According to a particular embodiment, the cellulose ester is a cellulose acetate butyrate, such as the reference Eastman Cellulose Acetate Butyrate ^® , marketed by Eastman Chemical.

According to a particular embodiment, the polymer(s) b) are chosen from nonionic polymers, in particular nonionic polysaccharides, more particularly inulins modified by hydrophobic chains, such as alkylcarbamate groups, in particular _C8 - _C18 alkyl carbamate, and more particularly laurylcarbamate.

As an example of these compounds, we can notably cite the product sold under the name Inutec SL1 by the company Creachem.

Among the polysaccharide esters, we can also mention pullulan esters. Pullulan is a polysaccharide consisting of maltotriose units.

According to one embodiment, the modified polysaccharides are polysaccharide esters. By polysaccharide esters is meant polysaccharides in which at least one of the hydroxy radicals is esterified by an acid to form ester groups -O-C(O)-R or -C(O)-OR, in which R denotes a saturated or unsaturated radical of 2 to 30 carbon atoms, in particular 11 to 19 carbon atoms, preferably 12 to 17 carbon atoms, such as 13 carbon atoms.

In particular, the polysaccharide ester is myristoyl pullulan.

According to a particular embodiment, the polymer(s) b) comprise at least one cationic modified polysaccharide.

Preferably, chemical or physical treatments to obtain at least one cationic group are applied to guar gums, carob gums, starches and celluloses.

The cationic groups may be of primary, secondary, tertiary or quaternary amine type, preferably quaternary, and comprise a _C6 - _C30 aliphatic chain.

According to a particular embodiment, the modified polysaccharide(s) b) are chosen from quaternized (poly)hydroxyethylcelluloses modified by groups comprising at least one aliphatic chain (or fatty chain), such as alkyl, arylalkyl, alkylaryl groups comprising at least 8 carbon atoms, or mixtures thereof.

The alkyl radicals carried by quaternized celluloses or hydroxyethylcelluloses preferably contain from 8 to 30 carbon atoms.

Aryl radicals preferably denote phenyl, benzyl, naphthyl or anthryl groups. Examples that may be mentioned are quaternized alkylhydroxyethylcelluloses with C ₈ -C ₃₀ fatty chains, such as the products Quatrisoft LM 200 ^® , Quatrisoft LM-X 529-18-A ^® , Quatrisoft LM-X 529-18-B ^® (C ₁₂ alkyl) and Quatrisoft LM-X 529-8 ^® (C ₁₈ alkyl) sold by Dow Corning, the products Crodacel QM ^® , Crodacel QL ^® (C ₁₂ alkyl) and Crodacel QS ^® (C ₁₈ alkyl) sold by Croda and the product Softcal SL 100 ^® sold by Dow Corning.

According to a particular embodiment, the modified polysaccharide(s) b) are chosen from guar gums modified by C ₁ -C ₂₀ (poly)hydroxyalkylammonium groups, preferably C ₁ -C ₆ (poly)hydroxyalkyl.

Examples that may be mentioned include hydroxymethyltrimmonium, hydroxyethyltrimmonium, hydroxypropyltrimmonium and hydroxybutyltrimmonium halide groups, preferably hydroxypropyltrimonium halide, preferably chloride.

Such cationic guar gums modified with hydroxyalkylammonium groups are for example sold by the company Solvay under the trade names Cationic Jaguar ^® C-14S Guar Hydroxypropyltrimonium Chloride, F Jaguar ^® C-13S Guar Hydroxypropyltrimonium Chloride, F Jaguar ^® C-17 Guar Hydroxypropyltrimonium Chloride, Jaguar ^® Excel Guar Hydroxypropyltrimonium Chloride, Jaguar ^® C-500 STD Guar Hydroxypropyltrimonium Chloride, Jaguar ^® C-162 Hydroxypropyl Guar Hydroxypropyltrimonium Chloride, Jaguar ^® Optima Guar Hydroxypropyltrimonium Chloride, and Jaguar ^® LS Hydroxypropyl Guar Hydroxypropyltrimonium Chloride.

According to a particular embodiment, the cationic non-aromatic cyclic polymers b) are in particular polysaccharides with amine groups, such as chitosans.

Preferably, the amine groups are primary, secondary, or tertiary amines, preferably primary.

Polysaccharides with amino groups also include their organic or mineral acid salts, their α or β anomers, their optical isomers of L or D configuration and their solvates, such as hydrates.

According to a particular embodiment, the polysaccharide(s) with amine group(s) is (are) chosen from those with _C5 - _C7 osidic units, as well as their organic or mineral acid salts, their α or β anomers, their optical isomers of L or D configuration and their solvates, such as hydrates.

More particularly, the polysaccharide(s) with amine group(s) has a _C6 osidic unit with amine group(s); these polysaccharides with amine group(s) are then called polyhexosamines.

According to a particular embodiment, the osidic units of the polysaccharide with amine group(s) are of anomeric β (beta) configuration and/or D configuration.

According to a particular embodiment, the osidic units of the polysaccharide with amine group(s) are linked together between the carbon 1 atoms of one osidic unit and the carbon 4 atoms of the other osidic unit, denoted (1→4), such as the polysaccharide with amine group(s) of the following formula (B), as well as their organic or mineral acid salts, their α or β anomers, their optical isomers of L or D configuration and their solvates, such as hydrates:

formula (B) in which:

- the radicals R _a , R _b , R _c of each osidic unit can be identical or different;

- n is an integer greater than or equal to 2, particularly inclusively between 3 and 3000;

- R _a , R _b , and R _c , which may be identical or different, represent a group i) hydroxy, ii) (C ₁ -C ₄ )alkoxy, the alkyl group of which may be optionally substituted in particular by one or more hydroxy groups, iii) carboxy, and iv) NR ₁ R ₂ with R ₁ and R ₂ as defined above, in particular R ₁ and R ₂ are chosen from the hydrogen atom and –C(O)-R'1 in which R'1 is as defined above; preferably R ₁ and R ₂ represent an i) hydrogen atom or ii) –C(O)-R'1 and R'1 representing a (C ₁ -C ₄ )alkyl group such as methyl;

it being understood that at least one of the radicals R _a , R _b or R _c of at least one osidic unit represents an NR ₁ R ₂ group and that at least one of the NR ₁ R ₂ groups of at least one osidic unit represents an NH ₂ group; preferably R _a of at least one osidic unit represents an NR ₁ R ₂ group with R ₁ which represents a hydrogen atom and R ₂ is chosen from i) a hydrogen atom or ii) a –C(O)-R'1 group, and R _b and R _c represent a hydroxy group, it being understood that at least one of the NR ₁ R ₂ groups of at least one osidic unit represents an NH ₂ group.

More particularly, the polysaccharide(s) with amine group(s) of the invention is (are) of the following formula (B1), as well as their organic or mineral acid salts, their α or β anomers, their optical isomers of L or D configuration and their solvates, such as hydrates:

formula (B1) in which:

- R' represents a hydrogen atom or a (C ₁ -C ₄ )alkylcarbonyl group, such as acetyl CH ₃ -C(O)-;

- R'' represents a hydrogen atom or a (C ₁ -C ₄ )alkyl group optionally substituted by a carboxy group, such as –CH(CO ₂ H)-CH ₃ ;

- n is an integer greater than or equal to 2, particularly inclusively between 3 and 3000;

it being understood that in the polysaccharide (B1) at least one osidic unit carries an amino group NH ₂ and at least one other osidic unit carries at least one group N(H)-R' with R' representing a (C ₁ -C ₄ )alkylcarbonyl group, such as acetyl CH ₃ -C(O)-.

Preferably, the osidic units of formula (B) or (B1) are of D configuration or also called D-glucopyrane.

In particular, the units of formula (B) or (B1) are of anomeric β (beta) configuration.

According to a particular embodiment, the polysaccharides of the invention are chosen from the compounds of the following formula (B2) as well as their acid salts, organic or mineral, and their solvates such as hydrates:

formula (B2) in which:

- R _a , R _b , and R _c , are as defined for (B) previously;

- the radicals R _a , R _b , R _c of each osidic unit can be identical or different;

- n is an integer greater than or equal to 2, particularly inclusively between 3 and 3000, more particularly between 5 and 2500, preferably between 10 and 2300;

it being understood that in the polysaccharide (B2) at least one of the radicals R _a , R _b or R _c of at least one osidic unit represents an NR ₁ R ₂ group and that at least one of the NR ₁ R ₂ groups of at least one osidic unit represents an NH ₂ group; preferably at least one osidic unit carries an R _a amino NH ₂ group and at least one other osidic unit carries a group R _a which represents -N(H)-R' with R' representing a (C ₁ -C ₄ )alkylcarbonyl group, such as acetyl CH ₃ -C(O)-.

Preferably, the polysaccharide(s) with amine group(s) is (are) chosen from chitin and chitosan and their derivatives, preferably chitosan.

More particularly, the polysaccharide(s) with amine group(s) is (are) chosen from those of the following formula (B3) as well as their organic or mineral acid salts, and their solvates such as hydrates:

formula (B3) in which:

- R ₁ and R ₂ are as defined in formulas (B), (B1) or (B2); and

- n is an integer greater than or equal to 2, particularly inclusively between 3 and 3000, more particularly between 5 and 2500, preferably between 10 and 2300;

it being understood that in the polysaccharide of formula (B3) at least one osidic unit carries an amino group NH ₂ and at least one other osidic unit carries a group N(H)-R' with R' representing a (C ₁ -C ₄ )alkylcarbonyl group such as acetyl CH ₃ -C(O)-.

More particularly, the polysaccharide(s) with amine group(s) of the invention is (are) chosen from chitosans of the following formula (B4) as well as their organic or mineral acid salts, and their solvates such as hydrates:

formula (B4) in which:

- R' ₁ representing a (C ₁ -C ₄ )alkyl group, such as methyl;

- n is an integer greater than or equal to 2, particularly inclusively between 3 and 3000;

- p is greater than 0 and ranges up to 0.5, preferably from 0.05 to 0.3, and better from 0.1 to 0.20, such as 0.15, with m + p being equal to 1;

it being understood that in chitosan at least one saccharide unit carries an amino group NH ₂ and at least one other saccharide unit carries a group N(H)-R' ₁ with R' representing a (C ₁ -C ₄ )alkylcarbonyl group, such as acetyl CH ₃ -C(O)-.

For example, when m = 0.7, p = 0.3 this means that 70% of the amine groups are free (unsubstituted), and 30% of the amino groups are N-alkyl(C ₁ -C ₄ )carbonylated, in particular N-acetylated, corresponding to the chitosan polymer of formula:

with n as defined previously.

In particular, the polysaccharide(s) with amine group(s) of the invention is (are) chosen from chitosans, salified using organic acid, preferably using monocarboxylic acid of formula (I) as defined below or polycarboxylic acid of formula (II) as defined below, even more preferably salified using carboxylic acid of formula (I), such as lactic acid.

Formula (I) is represented by the formula RC(O)-OH, with R representing a (hetero)aryl group, such as phenyl, (hetero)aryl(C ₁ -C ₄ )alkyl, such as benzyl, or (C ₁ -C ₃₀ )alkyl or an unsaturated C ₂ -C ₃₀ radical (i.e. comprising at least one ethylenic unsaturation, preferably one ethylenic unsaturation), said alkyl group or unsaturated C ₂ -C ₃₀ radical being optionally interrupted and/or optionally substituted, preferably by one or more hydroxy groups and unsubstituted by one or more amino radicals, R preferably denoting a (C ₁ -C ₆ )alkyl group optionally interrupted and/or optionally substituted by 1, 2 or 3 hydroxy groups, preferably R represents a (C ₁ -C ₄ )alkyl group, such as methyl or ethyl; in particular, the organic monocarboxylic acids (I) are chosen from acetic acid, glycolic acid, and lactic acid, more particularly from acetic acid and lactic acid, and the polycarboxylic acids of the following formula (II):

formula (II) in which A represents a polyvalent hydrocarbon group comprising from 1 to 30 carbon atoms, saturated or unsaturated, cyclic or non-cyclic, aromatic or non-aromatic, optionally interrupted by one or more heteroatoms, such as oxygen and/or optionally substituted in particular by one or more hydroxyl groups; and t represents an integer between 1 and 5 inclusive.

Preferably, A represents a divalent ( _C1 - _C6 )alkylene group optionally substituted in particular by one or more hydroxy groups and not substituted by at least one amino radical, and t is 1, 2 or 3.

Preferably, the polycarboxylic acids of formula (II) are chosen from tartaric acid, succinic acid, fumaric acid and citric acid and more particularly chosen from tartaric acid, succinic acid, fumaric acid and citric acid, and amino acids comprising more carboxylic acid radicals than amino groups, such as gamma-carboxyglutamic acid, aspartic acid, glutamic acid, in particular gamma-carboxyglutamic acid; in particular the salts of monocarboxylic acids other than pyrrolidonecarboxylic acid, 100 EO and 500 EO ethoxylated stearic acids and linoleic acid.

According to a particular embodiment, the polysaccharide(s) with amine group(s) are chosen from a mixture of polysaccharide(s) with amine group(s), one of which is a chitosan or one of its organic or mineral acid salts, preferably its organic acid salts, more particularly chosen from lactic acid, its α or β anomers, its optical isomers of L or D configuration and its solvates, such as hydrates.

According to a particular embodiment, the polysaccharide(s) with amine group(s) is a single polysaccharide with amine group(s), in particular a mixture of chitosan or one of their organic or mineral acid salts, or more particularly their organic acid salts, more particularly chosen from their lactic acid salt, their α or β anomers, their optical isomers of L or D configuration and their solvates, such as hydrates.

According to a particular embodiment, the polysaccharide(s) with amine group(s) is a single polysaccharide with amine group(s), in particular a chitosan or one of its organic or mineral acid salts, or more particularly its organic acid salts, preferably chosen from its lactic acid salt, its α or β anomers, its optical isomers of L or D configuration and its solvates, such as hydrates.

According to one embodiment, the acyclic polymers b) are chosen from nonionic polymers. The polymers b) can thus be chosen from alkyl esters or ethers of polyols, such as glycerol. As glycerol ester, mention may be made, for example, of polyglycerol isostearate, such as the product marketed under the name Isolan GI 34 ^® by the company Evonik. Mention may also be made of polyoxyalkylenated, more particularly polyoxyethylenated and/or polyoxypropylenated, fatty acid and glycerol esters, such as, for example, the ester of polyethylene glycol and stearic acid with the INCI name PEG-100 Stearate, polyoxyalkylenated, in particular polyoxyethylenated and/or polyoxypropylenated, fatty acid esters, optionally in combination with a fatty acid and glycerol ester, such as, for example, the PEG-100 Stearate/Glyceryl Stearate mixture.

Non-ionic acyclic polymers (b) may also refer to oxyalkylenated, in particular oxyethylenated and/or oxypropylenated, fatty alcohol ethers.

According to another embodiment, the nonionic acyclic polymers b) may be chosen from polyesters, in particular from polyhydroxy acids, in particular C8-C30 polyhydroxy acids such as polyhydroxystearic acid.

According to one embodiment, the nonionic acyclic polymers b) may be chosen from the (co)polymers P having at least one unit of formula (II), optionally at least one unit of formula (III).

formula (II) in which:

- q represents an integer greater than or equal to 2, and

- R ^a represents a hydrogen atom or a linear or branched (C ₁ -C ₄ )alkyl group, preferably R ^a represents a hydrogen atom;

formula (III) in which:

- t represents an integer greater than or equal to 2;

- R represents a hydrocarbon chain, cyclic or acyclic, linear or branched, saturated or unsaturated, aromatic or not, comprising from 1 to 10 carbon atoms, preferably R represents a (C ₁ -C ₆ )alkyl group, in particular methyl; and

- R ^a represents a hydrogen atom or a linear or branched (C ₁ -C ₄ )alkyl group, preferably R ^a represents a hydrogen atom;

Preferably, the (co)polymer(s ) P are copolymers.

According to a preferred embodiment, the (co)polymer(s) P comprise at least one unit of formula (II) and at least one unit of formula (III).

According to a preferred embodiment, the (co)polymer(s) P have a mass average molecular weight varying from 1000 g/mole to 1,000,000 g/mole, preferably from 5,000 g/mole to 500,000 g/mole, and more preferably from 10,000 g/mole to 300,000 g/mole.

According to a particular embodiment, the (co)polymer(s) P as defined above denote in particular poly(vinyl alcohol) (PVA).

In particular, the (co)polymer(s) P may be partially or fully hydrolyzed poly(vinyl alcohol) (PVA), in particular those marketed under the reference Kuraray Poval by the Kuraray Company, in particular the POVAL range, or those marketed by the Sigma-Aldrich Company (see for example https://www.sigmaaldrich.com/FR/fr/search/poly(vinyl-alcohol)?focus=products&page=1&perpage=30&sort=relevance&term=poly%28vinyl%20alcohol%29&type=product).

This may in particular be poly(vinyl alcohol) chosen from:

- poly(vinyl alcohol) with an average molecular weight M _w of 89000-98000, hydrolyzed at more than 99%;

- poly(vinyl alcohol) with an average molecular weight M _w of 30000-70000, hydrolyzed from 87% to 90%;

- poly(vinyl alcohol) with an average molecular weight M _w of 13000-23000, hydrolyzed from 87% to 89%;

- poly(vinyl alcohol) with an average molecular weight M _w of 9000-10000, hydrolyzed at 80%;

- poly(vinyl alcohol) with an average molecular weight M _w of 146000-186000, hydrolyzed at more than 99%;

- poly(vinyl alcohol) with an average molecular weight M _w of 85000-124000, hydrolyzed at more than 99%;

- poly(vinyl alcohol) with an average molecular weight M _w of 31000-50000, hydrolyzed from 98% to 99%;

- poly(vinyl alcohol) with an average molecular weight M _w of 31000-50000, hydrolyzed from 87% to 89%;

- poly(vinyl alcohol) with an average molecular weight M _w of 85000-124000, hydrolyzed from 87% to 89%;

- poly(vinyl alcohol) with an average molecular weight M _w of 146000-186000, hydrolyzed from 87% to 89%;

- poly(vinyl alcohol) with an average molecular weight M _w of 13000-23000, hydrolyzed at 98%;

- poly(vinyl alcohol) with an average molecular weight M _w of 130,000, hydrolyzed to more than 99%;

- fully hydrolyzed poly(vinyl alcohol);

- poly(vinyl alcohol) marketed by Sigma-Aldrich under the reference 4-88 Emprove ^® Essantial;

- poly(vinyl alcohol) marketed by Sigma-Aldrich Company under the reference 8-88 Emprove ^® Essantial (Cas number No. 9002-89-5, M _w equal to 67,000); or

- poly(vinyl alcohol) marketed by Sigma-Aldrich under the reference 40-88 Emprove ^® Essantial.

Preferably, the (co)polymer(s) according to the invention can be prepared from partially hydrolyzed poly(vinyl alcohol), more preferably 88% hydrolyzed.

In particular, this may be poly(vinyl alcohol) marketed by the Sigma-Aldrich Company under the reference 8-88 Emprove ^® Essantial.

According to a particular embodiment, the polymer(s) b) are chosen from acyclic polymers, preferably from anionic acyclic polymers.

By way of example, mention may be made of polymers b) chosen from amino acids modified by at least one _C8 - _C30 hydrocarbon chain, preferably _C8 - _C24 , and their salts, in particular acyl glutamic acids (INCI name: acyl glutamic acid) or one of their salts, such as acyl glutamates, in particular stearoyl glutamic acid or one of its salts, more particularly sodium stearoyl glutamate (INCI name).

Such compounds are marketed under the name Amisoft by the company Ajinomoto, and in particular under the references Amisoft CA, Amisoft LA, Amisoft HS 11 PF, Amisoft MK-11, Amisoft LK-11, Amisoft CK-11, or under the name Eumulgin SG by the company Cognis.

According to a particular embodiment, the polymer(s) b) are chosen from acyclic polyamino and hydrocarbon polymers. Such polymers do not comprise silicon atoms.

In particular, the polyamine polymer(s) may be chosen from diamine polymers, and more particularly from polyether diamines, in particular of formula H ₂ N-ALK-O-[ALK'-O] _m -ALK''-NH ₂ with ALK, ALK' and ALK'', identical or different, representing a linear or branched (C ₁ -C ₆ )alkylene group, and m representing an integer greater than or equal to 0, such as 4,7,10-trioxa-1,13-tridecanediamine or the compounds known under the reference Jeffamine from the company Hunstman, and more particularly α, ω-diamine polyethylene glycol and/or polypropylene glycol (with an amine function at the end of the chain), for example sold under the names Jeffamine D-230, D-400, D-2000, D-4000, ED-600, ED-9000, ED-2003.

In particular, the polyamino polymer(s) may be chosen from triamino polymers, namely containing three primary and/or secondary amine groups, preferably primary (NH ₂ ).

More particularly, they are chosen from triamine polyethers, in particular of formula ALK'''[(O-ALK')m-NH ₂ ] ₃ with ALK' as defined above and ALK''', representing a trivalent (C ₁ -C ₆ )alkylene group, linear or branched, and m representing an integer greater than or equal to 0.

As (poly)amino compounds which are triaminated, triaminated polyethers are particularly cited, and in particular α, ω-diamine polyethylene glycol and/or polypropylene glycol (with amine function at the end of the chain), for example sold under the names Jeffamine T-403.

According to a particular embodiment, the (poly)amine compound(s) comprise more than three primary and/or secondary amine groups, preferably primary (NH ₂ ).

In particular, the (poly)amine compound(s) are chosen from poly(meth)acrylates or poly(meth)acrylamides bearing side primary or secondary amine functions, more particularly chosen from poly(3-aminopropyl)methacrylamide and poly(2-aminoethyl)methacrylate.

According to a particular embodiment, the polyamine compound(s) are chosen from:

- poly(alkylene (C ₂ -C ₅ )imines), and preferably among polyethyleneimines and polypropyleneimines, in particular poly(ethyleneimine), in particular those sold under the reference 408700 by the company Aldrich Chemical or under the reference 408727 by the company Aldrich Chemical (example PM = 25000) or under the trade name Lupasol by BASF, in particular with a molecular weight of between 1,200 and 30,000,

- poly(allylamine), in particular that sold under the reference 479136 by the company Aldrich Chemical,

- polyvinylamines and their copolymers, in particular with vinylamides, in particular vinylamine/vinylformamide copolymers,

- polyamino acids with _NH2 groups such as polylysine, in particular that sold by the company JNC Corporation (formerly Chisso),

- amino dextran, in particular that sold by the company CarboMer Inc,

- polyvinyl amino alcohol, in particular that sold by the company CarboMer Inc,

- copolymers based on acrylamido( _C1 - _C6 )alkylamine, in particular based on acrylamidopropylamine, and

- their mixtures.

As amino polymers, α, ω-diamine polytetrahydrofurans (or polytetramethylene glycol) and α, ω-diamine polybutadienes can also be mentioned.

According to a particular embodiment, the (poly)amino compounds are chosen from hyperbranched polymers comprising at least one amino group and dendrimers carrying at least one amino group, in particular polyamidoamine PAMAM dendrimers with an ethylenediamine core and a terminal amine function.

According to a particular embodiment, the polymer(s) b) are chosen from polyamino acids, and preferably from proteins.

Preferably, the proteins are of plant origin. As examples of polymers b) chosen from plant proteins, mention may be made of soy proteins.

The acyclic polymers b) may be anionic, cationic or nonionic, preferably anionic, more preferably anionic, particularly carrying carboxyl, carboxylate, sulfate, sulfonic acid, sulfonate, phosphate, phosphonic acid, phosphonate group(s), preferably chosen from carboxylates and carboxylic acids.

According to a particular embodiment, the acyclic polymers b) are anionic, in particular carrying carboxylic groups or carboxylates of alkali or alkaline earth metals such as sodium, and are chosen from homo or copolymers of (meth)acrylic acid.

(Meth)acrylic acid copolymers are in particular copolymers of (meth)acrylic acid with alkyl (poly)ether (meth)acrylates, in particular copolymers of (meth)acrylic acid and POE/POP (meth)acrylate, for example polyether polycarbonate, sodium salt in aqueous solution for example marketed under the name “RSY 15007 Cosmetic Version” by the company Arkema-Coatex.

According to a preferred embodiment, the polymer(s) b) are chosen from:

- lignosulfonic acid, lignosulfonates, polystyrene sulfonic acid, polystyrene sulfonates, anionic polyanethol derivatives, in particular polyanethol sulfonates, and mixtures thereof,

- alkyl esters or ethers of polyols, in particular glycerol,

- anionic polysaccharides, preferably chosen from sulfated polysaccharides, in particular ulvans, dextran sulfates, carrageenans, and mixtures thereof, and carboxylate polysaccharides, in particular alginates,

- cationic polysaccharides, preferably chosen from polysaccharides with amine groups, in particular chitosans.

- modified polysaccharides, in particular chosen from polysaccharide esters, and preferably from pullulan esters,

- poly(alkylene (C ₂ -C ₅ )imines), and preferably among polyethyleneimines and polypropyleneimines, in particular poly(ethyleneimine),

- polyamino acids, and preferably among proteins,

- anionic acyclic polymers, bearing carboxylic groups or carboxylates of alkali or alkaline earth metals such as sodium, and chosen from homo or copolymers of (meth)acrylic acid, preferably from sodium polymethacrylates and copolymers of (meth)acrylic acid with alkyl (poly)ether (meth)acrylates, in particular copolymers of (meth)acrylic acid and POE/POP (meth)acrylate, and

- their mixtures.

According to a more preferred embodiment, the polymer(s) b) are chosen from:

- lignosulfonates, particularly of alkali or alkaline-earth metals such as sodium or calcium lignosulfates,

- carrageenans;

- chitosans;

- alginates, particularly of alkali or alkaline-earth metals such as sodium alginate,

- dextrans, in particular of alkali or alkaline earth metals, and dextrans sulfates of alkali or alkaline earth metals such as sodium dextran sulfate,

- polyhydroxystearic acids,

- starches and their derivatives, particularly phosphates such as hydroxypropyl corn distarch phosphate,

- pullulans and their ester derivatives, in particular of _C1 - _C30 carboxylic acid, preferably _C10 - _C20 , such as myristoyl pullulan,

- polyvinyl alcohols,

- optionally hydrolyzed proteins such as optionally hydrolyzed soy proteins, and

- their mixtures.

According to an even more preferred embodiment, the polymer(s) b) are chosen from:

- lignosulfonates,

- carrageenans,

- chitosans,

- alginates such as sodium alginate,

- dextrans such as sodium dextran sulfate,

- polyhydroxystearic acids,

- starches and their derivatives such as hydroxypropyl corn distarch phosphate,

- pullulans and its ester derivatives such as myristoyl pullulan,

- polyvinyl alcohols,

- proteins such as possibly hydrolyzed soy proteins, and

- their mixtures.

Inorganic compound c)

According to a particular embodiment, the composite materials according to the invention may also comprise at least one inorganic compound c) distinct from said bismuth oxycarbonate particles a).

The inorganic compound(s) (c) may be amorphous or crystalline forms, hydrated or non-hydrated, of oxides or hydroxides or oxy-hydroxides of alkali or alkaline-earth metals, in particular sodium, potassium, magnesium and calcium, or of transition metals, in particular titanium, aluminium, manganese, iron, copper, niobium and tantalum or of lanthanides, in particular cerium, or of poor metals, in particular zinc, indium and bismuth.

Inorganic oxides can also refer to amorphous or crystalline forms, hydrated or non-hydrated, of oxides or hydroxides or oxy-hydroxides of metalloids.

In particular, the inorganic compounds (c) may be amorphous or crystalline forms, hydrated or non-hydrated, including clays, of oxides or hydroxides or oxy-hydroxides of silicon such as silica SiO ₂ , lithium and/or sodium and/or potassium and/or ammonium and/or calcium and/or magnesium and/or aluminium and/or titanium and/or iron and/or zinc and/or bismuth silicates, aluminium and/or calcium and/or magnesium and/or sodium and/or titanium and/or iron and/or zinc and/or bismuth borosilicates.

In particular, the inorganic compounds (c) may be amorphous or crystalline forms, hydrated or non-hydrated, of inorganic carbides or sulphides or nitrides, such as silicon carbides, iron, copper and zinc sulphides or such as boron and silicon nitrides.

As metal oxides, mention may be made of the hydrated or non-hydrated forms of Al ₂ O ₃ , Al(OH) ₃ , SiO ₂ , TiO ₂ , MnO, MnO ₂ , FeO(OH), Fe ₃ O ₄ , Fe ₂ O ₃ , Cu(OH) ₂ , Cu ₂ O, CuO, Zn(OH) ₂ , ZnO, Nb ₂ O ₅ , In(OH) ₃ , In ₂ O ₃ , Ce ₂ O ₃ , CeO ₂ , Ta ₂ O ₅ , WO ₃ , Bi ₂ O ₃ , as well as their mixtures.

Preferably, the hydrated or non-hydrated forms of Al will be used.₂O₃such as Al(OH)₃, the hydrated or non-hydrated forms of SiO₂, TiO₂, ZnO, and their mixtures, more preferably the hydrated or non-hydrated forms of Al₂O₃such as Al(OH)_{3 ,}or even the hydrated or non-hydrated forms of SiO₂, TiO₂, ZnO and their mixtures, and even more preferably the hydrated or non-hydrated forms of Al203 such as Al(OH)₃, or SiO₂and their mixtures.

According to a preferred embodiment, the composite materials according to the invention do not comprise an inorganic compound c) distinct from said bismuth oxycarbonate particles a).

According to another preferred embodiment, the composite materials according to the invention comprise a single inorganic compound c) distinct from said bismuth oxycarbonate particles a), preferably chosen from inorganic oxides, and more preferably from silica, alumina, titanium dioxide and zinc oxide, and better still silica.

According to another preferred embodiment, the composite materials according to the invention comprise a single inorganic compound c) distinct from said bismuth oxycarbonate particles a), preferably chosen from inorganic hydroxides or inorganic oxy-hydroxides, more preferably from inorganic hydroxides, more preferably from Al(OH) ₃ , Zn(OH) ₂ , In(OH) ₃ or their mixtures, even more preferably from Al(OH) ₃ , Zn(OH) ₂ , and even better Al(OH) ₃ .

Preferably, the composite material according to the invention comprises one or more inorganic compounds c) distinct from said particles of bismuth oxycarbonate a), preferably chosen from inorganic oxides, and more preferably from zinc, titanium, silicon and/or aluminum oxides, preferably from silicon and/or aluminum oxides, optionally hydrated.

Preferably, the composite material according to the invention comprises one or more inorganic compounds c) distinct from said bismuth oxycarbonate particles a), preferably chosen from an inorganic oxide, more preferably chosen from Al(OH) ₃ , SiO ₂ , TiO ₂ and ZnO, and even more preferably chosen from Al(OH) ₃ or SiO ₂ .

Composite material preparation process

The composite materials according to the invention can in particular be obtained according to the preparation methods described below.

In particular, the composite materials according to the invention as defined above can be obtained in one or more stages.

The composite materials can in particular be obtained in a conventional manner by different processes, in particular bringing the bismuth oxycarbonate particles a) into contact with a solution comprising at least one polymer b) in a solvent or a mixture of solvents A.

In particular, the process for preparing composite materials according to the invention implements:

- bismuth oxycarbonate particles a) of formula (I) (BiO) _{2- x} (CO ₃ ), formula (I) as well as its solvates such as hydrates, in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm;

- optionally one or more precursors intended to form the inorganic compound(s) c) distinct from said bismuth oxycarbonate particles;

- one or more polymers b) as defined above;

- possibly one or more additives; and

- possibly one or more solvents.

According to a particular embodiment, the process for preparing the composite materials according to the invention may comprise one or more separation steps.

In particular, the precursor(s) intended to form the inorganic compound(s) c) distinct from said particles of bismuth oxycarbonate a) are chosen from organic or inorganic compounds which make it possible to obtain, by chemical reaction or physical adsorption, particles of bismuth oxycarbonate a) and of inorganic compound c).

In particular, said precursor(s) may be chosen from:

- inorganic compounds c) as described above,

- inorganic metallic precursors of chemical elements and their hydrates, in particular solubilized metallic oxides, in particular sodium silicates or aluminates, halides and their hydrates, nitrates and their hydrates, carbonates and their hydrates, sulfonates and their hydrates, sulfates and their hydrates, phosphates and their hydrates,

- organic metal precursors and their hydrates, in particular alkoxides and their hydrates, carboxylates and their hydrates, lactates and their hydrates, citrates and their hydrates, and

- their mixtures.

Said precursor(s) intended to form the additional inorganic compound(s) c) may also be chosen from oxidizing precursors, in particular air, hydrogen peroxide, peroxides and their hydrates, and/or sulfurizing precursors, in particular hydrogen sulfide, alkali sulfides and their hydrates, and/or nitriding precursors.

According to a preferred embodiment, the process for preparing the composite materials according to the invention does not use precursors intended to form the inorganic compound(s) c) distinct from said bismuth oxycarbonate particles a).

According to a preferred embodiment, the process for preparing the composite materials according to the invention uses at least one precursor intended to form the inorganic compound(s) c) distinct from said bismuth oxycarbonate particles a), and preferably chosen from sodium silicate and sodium aluminate.

According to a particular embodiment, the process for preparing composite materials according to the invention uses at least one solvent.

The choice of solvent(s) may in particular depend on the precursor(s) and additive(s) used in the process.

In particular, the solvent(s) may be chosen from polar or apolar, protic or aprotic solvents.

According to a particular embodiment, the method for preparing composite materials according to the invention uses at least one additive.

In particular, the additive(s) may be chosen from acids, in particular mineral acids, such as hydrochloric acid or sulfuric acid, and bases, preferably mineral bases, such as sodium hydroxide or potassium hydroxide.

According to a particular embodiment, the present invention aims at a process for preparing composite materials as defined above comprising at least the steps consisting of:

(i) having at least one particle of bismuth oxycarbonate a) of formula (I) (BiO) _{2- x} (CO ₃ ), formula (I) as well as its solvates such as hydrates, in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm, optionally in dispersion in at least one solvent or mixture of solvents A;

(ii) have a solution of at least one polymer b), optionally in a solvent or mixture of solvents B;

(iii) bringing together said at least one particle a) or dispersion (i) and said solution (ii) to form the composite material;

(iv) insulate said composite material.

Preferably, step (i) does not involve the use of solvent A.

According to one embodiment, the solvent(s) of steps (i) and (ii) may be identical or different.

In particular, the solvent(s) A and/or B are chosen from apolar aprotic solvents, polar and protic solvents, more preferably from water, alcohols, polyols and their mixtures.

In particular, when the polymer(s) b) are hydrophilic and/or amphiphilic, the solvent or mixture of solvents B is polar, and when the polymer(s) are hydrophobic and/or amphiphilic, the solvent or mixture of solvents B is non-polar.

In particular, when the polymer(s) b) are hydrophilic and/or amphiphilic, the solvent or mixture of solvents B is polar and protic, and preferably chosen from water, polyols, and/or their mixtures, and more preferably is water.

In particular, when the polymer(s) b) are hydrophobic and/or amphiphilic, the solvent or mixture of solvents B is apolar, and preferably chosen from volatile and non-volatile oils or organic solvents.

Preferably, the mixture (iii) is kept stirring at atmospheric pressure for a period ranging from 5 minutes to 24 hours, in particular at a temperature varying from 20°C to 200°C, and in particular in the open air or under an inert atmosphere.

According to a particular embodiment, the process for preparing the composite materials according to the invention may comprise one or more separation steps, in particular by centrifugation and/or by filtration, in particular ultrafiltration, and/or by freeze-drying and/or by atomization.

According to a particular embodiment, the method for preparing the composite materials further comprises a centrifugation step.

In particular, according to this embodiment, the method for preparing the composite materials further comprises:

- optionally, a step of adding a solvent or solvent mixtures S in which the polymer(s) b) is or are not soluble, i.e. the polymer b) precipitates in the solvent or solvent mixture S, at a temperature ranging from 0°C to room temperature, to precipitate the composite materials;

- at least one centrifugation step, preferably between 4000 rpm and 14000 rpm, in particular for a duration ranging from 1 min to 1 h; and

- optionally at least one washing step, preferably with the solvent or solvent mixture S;

- possibly at least one drying step, in particular in an oven, preferably at a temperature of 50°C and in particular under vacuum (pressure equal to 10 mmHg), to isolate the composite materials.

According to a particular embodiment, the method for preparing the composite materials further comprises a filtration step, in particular ultrafiltration.

In particular, according to this embodiment, the method for preparing the composite materials further comprises:

- possibly, a step of adding a solvent or solvent mixtures S,

- a step of separating the composite materials from the solvent mixture, by filtration, in particular by ultrafiltration, on a membrane preferably with a pore size ranging from 1 nm to 1 µm, even better from 1 to 100 nm,

- possibly at least one centrifugation step;

- possibly at least one washing step; and

- possibly at least one drying step, in particular in an oven, preferably at a temperature of 50°C and in particular under vacuum (pressure equal to 10 mmHg), to isolate the composite materials.

According to a particular embodiment, the method for preparing the composite materials further comprises a freeze-drying step.

In particular, according to this embodiment, the method for preparing the composite materials further comprises a step of freeze-drying the mixture, in particular at a temperature ranging from 0°C to -180°C, optionally after evaporation of one or more solvents when the reaction medium comprises several.

According to a particular embodiment, the method for preparing the composite materials further comprises an atomization step.

In particular, according to this embodiment, the method for preparing the composite materials further comprises a step of atomizing the mixture. In particular, the atomization temperature is preferably less than or equal to the lowest characteristic transition temperature of the polymer b) or of all the polymers b) constituting the mixture, the transitions referring to a possible glass transition and/or a possible melting and/or a possible degradation, and greater than the lowest boiling point of the solvent or solvents of the mixture. Preferably, the atomization temperature varies from 80 °C to 250 °C, more preferably from 100 °C to 200 °C, and even more preferably from 100 °C to 180 °C.

Cosmetic composition

The composite materials according to the invention can in particular be used in a composition, in particular in a cosmetic composition.

Thus, the present invention also relates to a composition, in particular cosmetic, comprising at least one composite material as defined above.

According to a preferred embodiment, the present invention also relates to a composition, in particular cosmetic, comprising at least:

(i) at least one composite material as defined above;

ii) at least one aqueous phase and/or at least one fatty phase; and

iii) at least one compound chosen from: 1) UV filters distinct from composite materials i); 2) coloring matters; 3) cosmetic active ingredients for the care of keratin materials; 4) surfactants; 5) thickeners; and mixtures thereof.

Said composite materials may be present in the composition, preferably cosmetic, in a content ranging from 0.5% to 70% by weight, preferably from 1% to 50% by weight, even better from 2 to 40% by weight relative to the total weight of the composition.

Aqueous phase

A composition, in particular a cosmetic composition, according to the invention may comprise at least one aqueous phase.

The aqueous phase may comprise water and optionally a water-soluble solvent.

In the present invention, the term " water-soluble solvent " means a compound which is liquid at room temperature and miscible with water (miscibility in water greater than 50% by weight at 25°C and atmospheric pressure).

The water-soluble solvents which can be used in a composition according to the invention can also be volatile.

Among the water-soluble solvents which may be used in a composition in accordance with the invention, mention may be made in particular of lower monoalcohols having from 1 to 5 carbon atoms such as ethanol and isopropanol, C ₂ -C ₃₂ polyols, C ₃ and C ₄ ketones and C ₂ -C ₄ aldehydes.

Among the water-soluble solvents that can be used in a composition in accordance with the invention, mention may be made in particular of polyols. By " polyol ", it is necessary to understand, for the purposes of the present invention, any organic molecule comprising at least two free hydroxyl groups.

A polyol suitable for the invention may be a compound of alkyl type, linear, branched or cyclic, saturated or unsaturated, carrying on the alkyl chain at least two –OH functions, in particular at least three –OH functions.

The polyols advantageously suitable for the formulation of a composition according to the present invention are those having in particular from 2 to 32 carbon atoms, preferably 3 to 16 carbon atoms.

Advantageously, the polyol may be chosen, for example, from pentaerythritol, trimethylolpropane, caprylyl glycol, glycerol, polyglycerols, such as glycerol oligomers such as diglycerol, polyethylene glycols, polypropylene glycols, and mixtures thereof.

Fat phase

A composition, in particular a cosmetic composition, according to the invention may further comprise at least one fatty phase, in particular an oily phase.

For the purposes of the invention, the term “fatty phase” means a phase comprising at least one fatty substance and all of the liposoluble and lipophilic ingredients used for the formulation of the compositions of the invention.

Preferably, the fatty phase comprises at least one oil, in particular a cosmetic oil.

" Oil " means a non-aqueous compound, immiscible with water, liquid at room temperature (25°C) and atmospheric pressure (760 mm Hg).

The fatty phase may comprise at least one volatile or non-volatile hydrocarbon oil and/or a fatty substance.

As non-volatile hydrocarbon oils, mention may in particular be made of hydrocarbon oils of vegetable origin, synthetic ethers having from 10 to 40 carbon atoms, linear or branched hydrocarbons, of mineral or synthetic origin, synthetic esters, fatty alcohols which are liquid at room temperature with a branched and/or unsaturated carbon chain having from 12 to 26 carbon atoms, higher fatty acids in C ₁₂ -C ₂₂ , carbonates, and mixtures thereof.

Examples of volatile hydrocarbon oils include hydrocarbon oils with 8 to 16 carbon atoms.

Non-volatile silicone oils may be chosen in particular from non-volatile polydimethylsiloxanes (PDMS) and phenylated silicones. As volatile silicone oils, examples that may be mentioned are volatile linear or cyclic silicone oils.

Fluorinated volatile oils, such as nonafluoromethoxybutane, nonafluoromethoxybutane, decafluoropentane, tetradecafluorohexane, dodecafluoropentane and mixtures thereof, may also be used.

The oily phase may further comprise, mixed with or dissolved in the oil, other fatty substances. Another fatty substance that may be present in the oily phase may be, for example, a fatty acid, a wax, a gum, a pasty compound, or mixtures thereof.

1) Additional UV filters

According to a particular embodiment, a composition according to the invention comprises 1) at least one complementary UV filter distinct from the composite materials required according to the invention and defined above.

By “ complementary UV filter distinct from composite materials ” is meant, for the purposes of the present invention, any UV filter whose chemical nature differs from that of the composite materials required according to the invention and defined above.

The composite materials according to the invention can therefore be used alone or in combination with 1) other UV filters, in particular chosen from organic and/or inorganic UV filters.

Thus, the cosmetic composition may also contain one or more complementary UV filters chosen from hydrophilic, lipophilic or insoluble organic UV filters and/or mineral UV filters, different from the composite materials according to the invention.

By " hydrophilic UV filter " is meant any organic or inorganic cosmetic or dermatological compound filtering UV radiation capable of being completely dissolved in the molecular state in a liquid aqueous phase or of being in colloidal suspension (for example in micellar form) in a liquid aqueous phase.

By " lipophilic UV filter " is meant any organic or inorganic cosmetic or dermatological compound filtering UV radiation capable of being completely dissolved in the molecular state in a liquid fatty phase or of being in colloidal suspension (for example in micellar form) in a liquid fatty phase.

By " insoluble UV filter " is meant any organic or inorganic cosmetic or dermatological compound filtering UV radiation having a solubility in water of less than 0.5% by weight and a solubility of less than 0.5% by weight in most organic solvents such as paraffin oil, fatty alcohol benzoates and fatty acid triglycerides, for example Miglyol 812 ^® . This solubility, achieved at 70 °C, is defined as the quantity of product in solution in the solvent at equilibrium with an excess of suspended solid after returning to room temperature. It can easily be evaluated in the laboratory.

Complementary organic UV filters are chosen in particular from:

- cinnamic compounds, in particular Ethylhexyl Methoxycinnamate,

- anthranilate compounds, in particular Menthyl anthranilate,

- salicylic compounds, in particular Homosalate and Ethylhexyl Salicylate,

- dibenzoylmethane compounds, in particular Butyl Methoxydibenzoylmethane,

- benzylidene camphor compounds, in particular 3-Benzylidene camphor, 4-Methylbenzylidene camphor, Benzylidene Camphor Sulfonic Acid and Terephthalylidene Dicamphor Sulfonic Acid,

- benzophenone compounds, in particular oxybenzone and n-hexyl 2-(4-diethylamino-2-hydroxybenzoyl)-benzoate,

- β,β-diphenylacrylate compounds, in particular octocrylene,

- triazine compounds, in particular Phenylene Bis-Diphenyl triazine, Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine, Ethylhexyl Triazone and Diethylhexyl Butamido Triazone,

- benzotriazole compounds, in particular Drometrizole Trisiloxane,

- benzalmalonate compounds, in particular those cited in US patent 5624663, in particular Polysilicone-15,

- benzimidazole derivatives, in particular Phenylbenzimidazole Sulfonic Acid,

- imidazoline compounds, in particular Ethylhexyl Dimethoxybenzylidene Dioxoimidazoline Propionate,

- bis-benzoazolyl compounds, as described in patents EP 0669323 and US 2463264, in particular Disodium Phenyl Dibenzimidazole Tetra-sulfonate,

- para-aminobenzoic compounds, in particular PABA, Ethylhexyl Dimethyl PABA and PEG-25 PABA,

- methylene bis-(hydroxyphenyl benzotriazole) compounds, as described in applications US 5237071, US 5166355, GB 2303549, DE 19726184 and EP 0893119, in particular Methylene bis-Benzotriazolyl Tetramethylbutylphenol,

- benzoxazole compounds, as described in patent applications EP 0832642, EP 1027883, EP 1300137 and DE 10162844, in particular 2,4-bis-[5-1(dimethylpropyl)benzoxazol-2-yl-(4-phenyl)-imino]-6-(2-ethylhexyl)-imino-1,3,5-triazine,

- filter polymers and filter silicones, such as those described in particular in application WO 93/04665,

- dimers derived from α-alkylstyrene, such as those described in patent application DE 19855649,

- 4,4-diarylbutadienes compounds, as described in applications EP 0967200, DE 19746654, DE 19755649, EP 1008586, EP 1133980 and EP 0133981, in particular 1,1-dicarboxy(2,2’-dimethyl-propyl)-4,4-diphenylbutadiene, and

- their mixtures.

Complementary inorganic UV filters are generally mineral UV filters, particularly chosen from metal oxides.

The metal oxides may be chosen in particular from titanium, zinc, iron, zirconium, cerium oxides, and their mixtures.

Metal oxide particles can be coated or uncoated.

The coated particles are more particularly titanium oxides coated with silica, silica and iron oxide, silica and alumina, alumina, alumina and aluminum stearate, silica, alumina and alginic acid, alumina and aluminum laurate, iron oxide and iron stearate, zinc oxide and zinc stearate, silica and alumina and treated with a silicone, silica, alumina, aluminum stearate and treated with a silicone, silica and treated with a silicone, alumina and treated with a silicone, triethanolamine, stearic acid, sodium hexametaphosphate, or TiO ₂ treated with octyl trimethyl silane, TiO ₂ treated with a polydimethylsiloxane, polydimethylhydrogensiloxane-treated anatase/rutile TiO ₂ , TiO ₂ coated with triethylhexanoin, aluminum stearate and alumina, TiO ₂ coated with aluminum stearate, alumina and silicone, TiO ₂ coated with lauroyl lysine, or TiO ₂ coated with C _9-15 fluoroalcohol phosphate and aluminum hydroxide.

Metal oxides can optionally be doped.

In this respect, we can cite _TiO2 particles doped with at least one transition metal such as iron, zinc, manganese, and more particularly manganese.

The doped particles may be in the form of a dispersion, preferably an oily dispersion. The oil present in the oily dispersion is preferably chosen from triglycerides, including those of capric/caprylic acids. The oily dispersion of titanium oxide particles may additionally comprise one or more dispersing agents, for example a sorbitan ester or a polyoxyalkylenated fatty acid and glycerol ester. More particularly, mention may be made of the oily dispersion of manganese-doped TiO ₂ particles in capric/caprylic acid triglyceride in the presence of tri-PPG-3 myristylether citrate and polyglyceryl-3-polyricinoleate and sorbitan isostearate.

Mention may also be made of mixtures of metal oxides, in particular titanium dioxide and cerium dioxide, including the equal-weight mixture of titanium dioxide and cerium dioxide coated with silica, as well as the mixture of titanium dioxide and zinc dioxide coated with alumina, silica and silicone or coated with alumina, silica and glycerin.

2) Coloring materials

According to a particular embodiment, a composition according to the invention comprises 2) at least one coloring material.

Generally speaking, a " coloring material " is intended to designate any compound capable of coloring a composition, that is to say which absorbs in the visible spectrum, in particular so as to appear to the human eye as a color such as yellow, orange, red, violet, blue or green.

Preferably, a composition according to the invention comprises at least one pigment.

By " pigments " is meant white or colored particles, mineral or organic, insoluble in liquid hydrophilic and lipophilic phases, intended to color and/or opacify the composition containing them, and different from the composite materials according to the invention. More particularly, the pigments are slightly or not at all soluble in hydroalcoholic media.

The pigments that can be used are in particular chosen from organic and/or mineral pigments known in the art, in particular those described in Kirk-Othmer's Encyclopedia of Chemical Technology and in Ullmann's Encyclopedia of Industrial Chemistry (Ullmann's Encyclopedia of Industrial Chemistry "Pigment organics", 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 10.1002/14356007.a20 371 and ibid, "Pigments, Inorganic, 1. General” 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim10.1002/14356007.a20_243.pub3).

These pigments can be in the form of powder or pigment paste. They can be coated or uncoated.

The pigments can for example be chosen from mineral pigments, organic pigments, lakes, special effect pigments such as mother-of-pearl or glitter, and mixtures thereof.

The pigment may be a mineral pigment. By mineral pigment is meant any pigment that meets the definition of the Ullmann encyclopedia in the inorganic pigment chapter. Among the mineral pigments useful in the present invention, mention may be made of iron or chromium oxides, manganese violet, ultramarine blue, chromium hydrate, ferric blue and titanium oxide.

The pigment may be an organic pigment.

By organic pigment is meant any pigment that meets the definition of the Ullmann encyclopedia in the organic pigment chapter.

The organic pigment may in particular be chosen from nitroso, nitro, azo, xanthene, quinoline, anthraquinone, phthalocyanine, metal complex type compounds, isoindolinone, isoindoline, quinacridone, perinone, perylene, diketopyrrolopyrrole, thioindigo, dioxazine, triphenylmethane, quinophthalone.

Preferably, the pigment(s) suitable for the invention are chosen from carbon black, iron oxides, in particular red, brown or black, micas coated with iron oxide, triarylmethane pigments, in particular blue and violet, such as BLUE 1 LAKE, azo pigments, in particular red, such as D&C RED 7, alkali metal salts of lithol red, such as the calcium salt of lithol red B, more preferably the pigment(s) used are chosen from red iron oxides and azo pigments, in particular red, such as D&C RED 7.

The coloring matter(s) may be present in a composition according to the invention in a content ranging from 0.001 to 10% by weight, preferably from 0.005% to 5% by weight, relative to the total weight of the composition.

According to a particular embodiment of the invention, the quantity of pigments varies from 0.5% to 40%, and preferably from 1 to 20% relative to the weight of the composition of the invention comprising them.

3) Cosmetic active ingredient

According to a particular embodiment, a composition according to the invention comprises 3) at least one cosmetic active ingredient for caring for keratin materials, preferably for caring for the skin.

In particular, the cosmetic active ingredient may be at least one hydrophilic active ingredient and/or one lipophilic active ingredient, preferably hydrophilic.

The term “ hydrophilic active ” means a water-soluble or water-dispersible active agent capable of forming hydrogen bonds.

As cosmetic active ingredients 3), mention may be made, for example, of moisturizing agents, depigmenting agents, desquamating agents, humectants, anti-aging agents, mattifying agents, healing agents, antibacterial agents, vitamins and their derivatives or precursors, antioxidant compounds, anti-radical agents, anti-polluting agents, self-tanning agents, anti-glycation agents, soothing agents, deodorant agents, essential oils, NO-synthase inhibitors, agents stimulating the synthesis of dermal or epidermal macromolecules and/or preventing their degradation, agents stimulating the proliferation of fibroblasts, agents stimulating the proliferation of keratinocytes, myorelaxant agents, refreshing agents, tensing agents, depigmenting agents, pro-pigmenting agents, keratolytic agents, slimming agents, agents acting on the energy metabolism of cells, insect repellents, substance P or CRGP antagonists, anti-hair loss agents, and mixtures thereof

The asset(s) may in particular be chosen from:

- vitamins and their derivatives, in particular their esters, such as niacinamide (3-pyridinecarboxamide) nicotinamide (vitamin B3), tocopherol (vitamin E) and its esters (such as tocopheryl acetate), ascorbic acid and its derivatives (vitamin C), retinol (Vitamin A),

- humectants or moisturizers such as urea, hydroxyureas, glycerol, polyglycerols, glycerolglucoside, diglycerolglucoside, polyglycerylglucosides, xylitylglycoside and plant extracts (in particular tea, mint, orchid, soya, aloe vera, honey, and in particular glycerol;

- C-glycoside compounds, and preferably hydroxypropyl tetrahydropyrantiol (INCI name) (or proxylane);

- antioxidant compounds;

- anti-aging active ingredients, such as hyaluronic acid compounds, and in particular sodium hyaluronate, salicylic acid compounds and in particular n-octanoyl-5-salycilic acid (capryloyl salicylic acid), adenosine, and the sodium salt of 3-hydroxy-2-pentylcyclopentyl)acetic acid;

- keratolytic agents such as lactic acid or glycolic acid; and

- their mixtures.

Such active ingredients may be present in a composition according to the invention in a content ranging from 0.05% to 10% by weight, preferably from 1.0% to 8.0% by weight, relative to the total weight of the composition.

4) Surfactant

According to a particular embodiment, a composition according to the invention comprises 4) at least one surfactant.

The surfactants may be selected from nonionic, anionic, cationic, amphoteric surfactants, and mixtures thereof. Reference may be made to the document “Encyclopedia of Chemical Technology, KIRK-OTHMER”, volume 22, p. 333-432, 3rd edition, 1979, WILEY, for the definition of the emulsifying properties and functions of surfactants, in particular p. 347-377 of this reference, for anionic, amphoteric and nonionic surfactants.

Examples of amphoteric surfactants suitable for the invention are in particular chosen from betaines, preferably chosen from alkyl betaines, in particular lauryl betaine; N-alkylamido betaines and their derivatives, in particular cocamidopropyl betaine, lauramidopropyl betaine and N-carboxyethoxyethyl N-cocoylamidoethyl aminoacetate N-disodium; sultaines, in particular cocoyl amidopropylhydroxy sultaine; and mixtures thereof.

The nonionic surfactants may be chosen in particular from poly(ethylene oxide) alkyl- and polyalkyl-esters, oxyalkylenated alcohols, poly(ethylene oxide) alkyl- and polyalkyl-ethers, polyoxyethylenated or non-polyoxyethylenated sorbitan alkyl- and polyalkyl-esters, polyoxyethylenated or non-polyoxyethylenated sorbitan alkyl- and polyalkyl-ethers, in particular sucrose alkyl- and polyalkyl-esters, polyoxyethylenated or non-polyoxyethylenated glycerol alkyl- and polyalkyl-ethers, polyoxyethylenated or non-polyoxyethylenated glycerol alkyl- and polyalkyl-ethers, geminal surfactants, cetyl alcohol, stearyl alcohol, and mixtures thereof.

The anionic surfactants may be chosen from alkyl ether sulfates, carboxylates, amino acid derivatives, sulfonates, isethionates, taurates, sulfosuccinates, alkylsulfoacetates, phosphates and alkylphosphates, polypeptides, metal salts of C fatty acids₁₀-C₃₀, especially in C₁₆-C₂₅, especially metal stearates and behenates and their mixtures.

The cationic surfactants may be chosen from alkylimidazolidiniums, such as isostearylethylimidonium ethosulfate, ammonium salts, such as (C _12-30 alkyl)-tri(C _1-4 alkyl)ammonium halides such as N,N,N-trimethyl-1-docosaminium chloride (or Behentrimonium chloride).

Silicone surfactants can be chosen from dimethicone copolyols or silicone elastomers.

A composition according to the invention may comprise between 0.01% and 2.0% by weight of surfactant, preferably between 0.05% and 1.5% by weight, more preferably between 0.1% and 1.0% by weight, relative to the total weight of the composition.

5) Thickener

According to a particular embodiment, a composition according to the invention comprises 5) at least one thickener, also sometimes called gelling agent or viscosity modifying agent.

Thickeners can be synthetic, natural or naturally derived, preferably natural or naturally derived.

Such thickeners may more particularly be chosen from natural polymers or polymers of natural origin, in particular of plant origin.

These thickeners are preferably hydrophilic, that is to say soluble or dispersible in water.

Advantageously, the thickener(s) are chosen from polysaccharides, modified or native, in particular modified or unmodified starches, fructans, gellans, glucans, amylose, amylopectin, glycogen, pullulan, dextrans, celluloses and their derivatives, in particular methylcelluloses, hydroxyalkylcelluloses, ethylhydroxyethylcelluloses, and carboxymethylcelluloses, mannans, xylans, lignins, arabans, galactans, galacturonans, alginate-based compounds, chitin, chitosans, glucuronoxylans, arabinoxylans, xyloglucans, glucomannans, pectic acids and pectins, arabinogalactans, carrageenans, agars, glycosaminoglucans, gum arabic, sclerotium gum, tragacanth gum, ghatti gum, karaya gum, locust bean gum, konjac gum, galactomannans such as guar gum and their non-ionic derivatives, in particular hydroxypropyl guar, and ionic, biopolysaccharide gums of microbial origin, in particular scleroglucan or xanthan gum, mucopolysaccharides, carboxyvinyl polymers, polyacrylamides, polymers and copolymers of 2-acrylamido-2-methylpropanesulfonic acid, optionally crosslinked and/or neutralized, water-soluble or water-dispersible silicone derivatives, such as acrylic silicones, polyether silicones and cationic silicones, and mixtures thereof.

The thickener(s) may be present in a composition according to the invention in a content ranging from 0.05 to 5.0% by weight, in particular from 0.3% to 4.0% by weight, more particularly from 0.4% to 2.5% by weight, relative to the total weight of the composition.

Adjuvants

A composition according to the invention may also comprise at least one adjuvant usual in the cosmetic field chosen from perfumes, film-forming polymers, pH adjusters (acids or bases), for example citric acid, tartaric acid or oxalic acid, chelating agents, preservatives, softeners, sweeteners, anti-foaming agents, fillers, trace elements, propellants, and mixtures thereof.

Of course, the person skilled in the art will take care to choose this or these possible additional compounds and/or their quantity in such a way that the advantageous properties of a composition according to the invention are not, or not substantially, altered by the envisaged addition.

Of course, the person skilled in the art will take care to choose this or these possible complementary compounds, and/or their quantity, in such a way that the advantageous properties of the particles according to the invention are not, or not substantially, altered by the envisaged addition.

As stated above, a composition according to the invention may be cosmetic, and preferably is cosmetic.

A composition according to the invention is generally suitable for topical application to the skin and therefore generally comprises a physiologically acceptable medium, i.e. compatible with the skin.

It is preferably a cosmetically acceptable medium, that is to say which has a pleasant color, odor and feel and does not generate unacceptable discomfort, that is to say tingling, tightness, likely to dissuade the user from applying this composition.

Galenic forms of the compositions

The compositions, in particular cosmetic compositions, containing the particles according to the invention can be prepared according to techniques well known to those skilled in the art.

They can be presented in all classic galenic forms depending on the intended applications and are suitable for topical application, that is to say for application on the surface of the keratin materials considered.

Cosmetic compositions can be presented in the form of an aqueous or hydroalcoholic gel.

They can be presented in the form of an emulsion, simple or complex (O/W, W/O, O/W/O or W/O/W), such as a cream, a milk, or a cream gel.

They can also be present in anhydrous form, for example in the form of an oil.

The term " anhydrous composition " means a composition containing less than 5% by weight of water, or even less than 2% water, better still less than 1% water and in particular free of water, the water not being added during the preparation of the composition but corresponding to the residual water provided by the mixed ingredients.

Cosmetic compositions can, for example, be used as make-up products.

Cosmetic compositions may, for example, be used as a care and/or sun protection product for the face and/or body of liquid to semi-liquid consistency, and have the appearance of a white or colored cream, more or less creamy, an ointment, a milk, a gel-cream, a lotion, a serum, a paste or a mousse. It may possibly be applied to the skin in the form of an aerosol. It may also be in solid form, for example in the form of a stick.

Cosmetic compositions may be in the form of skin or semi-mucous membrane care products, such as a protective composition, cosmetic care for the face, lips, hands, feet, anatomical folds or body (for example day creams, night creams, day serums, night serums, make-up remover creams, make-up bases, protective or care body milk, after-sun milk, lotion, gel or foam for skin or scalp care, serum, mask or after-shave composition).

The composition can be applied by hand or using an applicator.

In particular, the cosmetic compositions have an SPF value greater than 5 and preferably greater than 10.

For the purposes of the invention, the term " SPF " (Sun Protection Factor) means: the sun protection factor which measures the level of protection against UV radiation. The SPF value corresponds to the ratio between the minimum time required to obtain a sunburn (erythematogenic) with a sun protection composition and the minimum time without a sun protection composition to obtain said sunburn. More specifically, the term " SPF " is defined in the article A new substrate to measure sunscreen protection factor across the ultraviolet spectrum, J. Soc. Cosmet. Chem., 40, 127-133 (May/June 1989).

The SPF (Sun Protection Factor) assessment can be performed in vitro with a Labsphere® spectrophotometer. The plate is the material on which the sunscreen composition is applied. For this protocol, poly(methyl methacrylate) (PMMA) plates have proven to be ideal.

The evaluation of the Sun Protection Factor (SPF) of the compositions can also be carried out in vivo according to the ISO 24444 protocol “Cosmetics - Sun protection test methods - In vivo determination of the sun protection factor (SPF) (2010)”.

- " UVAPF " means: the index characterizing protection against UVA radiation. In particular, this index could be measured in vivo using the PPD (Persistent Pigment Darkening) method: " PPD " measures the skin color observed 2 to 4 hours after exposure to UVA. This method has been adopted since 1996 by the Japan Cosmetic Industry Association (JCIA) as the official test procedure for UVA labeling of products and is frequently used by testing laboratories in Europe and the United States (Japan Cosmetic Industry Association Technical Bulletin. Measurement standards for the effectiveness of UVA protection issued on November 21, 1995 and in force since January 1, 1996). The evaluation of UVA protection can also be measured in vitro with the Labsphere® spectrophotometer. The plate is the material on which the sunscreen composition is applied. For this protocol, polymethyl methacrylate (PMMA) sheets have proven to be ideal. The ISO 24443 protocol describes such an in vitro method.

Cosmetic processes and uses

The present invention also relates to the non-therapeutic cosmetic use of the composite materials according to the invention for filtering UV radiation, preferably UV-B, comprising at least the application to keratin materials of a composition comprising at least one composite material as defined above.

The present invention also relates to a non-therapeutic cosmetic process for filtering UV radiation, in particular UV-B, comprising at least the application to keratin materials of a composition comprising at least one composite material as defined above.

According to yet another of its aspects, the present invention also relates to the non-therapeutic cosmetic use of a cosmetic composition comprising at least one composite material defined above, to prevent the appearance on the skin, in particular on the face, neckline, arms, hands and/or shoulders, of darker and/or more colored spots giving the skin a color heterogeneity.

The present invention also relates to a non-therapeutic cosmetic process for limiting the darkening of keratin materials, in particular human materials, such as the skin, and/or keratin fibers, in particular human materials, such as the hair, and/or improving the color and/or uniformity of the complexion or of the keratin fibers, comprising the application to the surface of said keratin materials and/or of said keratin fibers of at least one cosmetic composition comprising at least one composite material defined above.

The present invention further relates to the non-therapeutic cosmetic use of a cosmetic composition comprising at least one composite material defined above, to prevent premature aging of keratin materials, in particular human keratin materials, such as the skin, in particular the skin of the face, neckline, arms, hands and/or shoulders.

It also relates to a non-therapeutic cosmetic process for preventing and/or treating the signs of aging of a keratin material, in particular human keratin material, in particular the skin, comprising the application to the surface of the keratin material of at least one cosmetic composition comprising at least one composite material defined above.

According to one of its aspects, the present invention relates to composite materials as defined above, for their use as agents for the filtration of UV radiation, in particular UV-B.

For the purposes of the present invention, the term " prevent " or " prevention " means reducing, at least in part, the risk of occurrence of a given phenomenon, for example the signs of aging of a keratin material, in particular human, such as the skin or the appearance on said keratin material, in particular human, such as the skin, of darker and/or more colored spots giving the skin a heterogeneity of color and/or premature aging of the skin.

In the description and examples, the percentages are weight or molar percentages. The ingredients are mixed, in the order and under the conditions easily determined by those skilled in the art.

The invention will now be described by means of the following examples given of course as illustrations and not as limitations of the invention.

Example 1 : Preparation of particles ’ bismuth oxycarbonate according to ’ invention

Bismuth oxycarbonate particles 1 and 2 are synthesized according to the preparation methods described below in Examples 1.A and 1.B.

The morphology of bismuth oxycarbonate particles was determined by direct observation by transmission electron microscopy. 1 to 5 milligrams of dry particles were dispersed in 10 mL of absolute ethanol and treated in an ultrasonic bath for two minutes. 5 µL of dispersion were then placed on an observation grid (copper with a carbon surface layer) and dried in ambient air.

Observation was performed with a Hitachi HT 7700 transmission electron microscope at an accelerating voltage of 100 kV. Average dimensions were obtained via particle size measurement by image analysis using ImageJ software (C.A. Schneider, W.S. Rasband, K.W. Eliceiri, NIH Image to ImageJ: 25 years of image analysis, Nat. Methods. 9 (2012) 671–675).

Example 1. HAS : Synthesis of s particles d ’ bismuth oxycarbonate 1

A solution of bismuth nitrate pentahydrate Bi(NO ₃ ) ₃ ·5H ₂ O (0.40 M) and D-mannitol (2 M) is prepared in 800 mL of water and stirred until the reagents are completely dissolved. 160 mL of ammonium carbonate solution (2.1 equivalents relative to bismuth) is then added. A white solid precipitates. After 30 minutes, this mixture is then transferred to a Teflon autoclave reactor and heated for 12 hours at 150 °C. The bismuth oxycarbonate particles 1 are isolated by centrifugation and washed 3 times with water before being dried in an oven at 60 °C.

Bismuth oxycarbonate particles 1 are platelets of the following average dimensions:

Average length L: 85 nm

Average width l: 52 nm

Average thickness e: 28 nm

Example 1.B: Synthesis of s particles d ’ bismuth oxycarbonate 2

A solution of bismuth nitrate pentahydrate Bi(NO ₃ ) ₃ ·5H ₂ O (0.40 M) and D-mannitol (0.87 M) is prepared in 800 mL of water and stirred until the reagents are completely dissolved. 160 mL of ammonium carbonate solution (2.1 equivalents relative to bismuth) are then added. A white solid precipitates. This mixture is then transferred to a Teflon autoclave reactor and heated for 7.5 hours at 125 °C. Product 2 is isolated by centrifugation and washed 3 times with water before being dried in an oven at 60 °C.

Bismuth oxycarbonate particles 2 are platelets of the following average dimensions:

Average length L: 86 nm

Average width l: 53 nm

Average thickness e: 28 nm

Example 2: Synthesis of composite materials according to ’ invention

Example 2. HAS 1 : Atomization synthesis of materials bismuth oxycarbonate/carrageenan composites, with a mass ratio of 1 , 66

A solution of Carrageenan (INCI name CARRAGEENAN) (0.6 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution, 1 g of bismuth oxycarbonate particles according to example 1A are added and the suspension is subjected to ultrasound for 15 minutes, then stirred overnight at room temperature. The white dispersion obtained is then atomized at 150 °C, with a pump flow rate of 15%, a suction flow rate of 80% and a number of Noddles of 2 (Device type: Mini-Atomizer B-290 BUCHI).

Composite material A1 is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2. HAS 2: Atomization synthesis of materials bismuth oxycarbonate/carrageenan composites, with a mass ratio of 0 , 5

A solution of Carrageenan (INCI name CARRAGEENAN) (2 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The viscous medium is then cooled to room temperature.

To this viscous solution, 1 g of bismuth oxycarbonate particles according to Example 1A are added, and the suspension is subjected to ultrasound for 15 minutes, then stirred overnight at room temperature. The white dispersion obtained is then atomized at 150 °C, with a pump flow rate of 15%, a suction flow rate of 80% and a number of Noddles of 4 (Device type: BUCHI B-290 Mini-Atomizer).

The composite material A2 , is isolated in the form of a white-beige powder and is characterized by UV/Vis spectrophotometry.

Example 2.B1: Synthesis by freeze-drying, of materials bismuth oxycarbonate/carrageenan composites, with a mass ratio of 1 , 66

A solution of Carrageenan (INCI name CARRAGEENAN) (0.6 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 minutes, then stirred overnight. The white dispersion obtained is then lyophilized.

Composite material B1 is isolated as a white solid and is characterized by UV/Vis spectrophotometry.

Example 2.B2: Synthesis by freeze-drying, of materials bismuth oxycarbonate/carrageenan composites, with a mass ratio of 4 , 16

A solution of Carrageenan (INCI name CARRAGEENAN) (0.24 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then lyophilized.

Composite material B2 is isolated as a white solid and is characterized by UV/Vis spectrophotometry.

Example 2.C1: Synthesis by centrifugation, of materials bismuth oxycarbonate/carrageenan composites, with a mass ratio of 1 , 66

A solution of Carrageenan (INCI name CARRAGEENAN) (0.6 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to Example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then centrifuged. The pellet is washed with ethanol and centrifuged again. The solid obtained is dried in a vacuum oven at 50 °C.

The composite material C1 is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2.C2: Synthesis by precipitation/centrifugation, of materials bismuth oxycarbonate/carrageenan composites, with a mass ratio of 1 , 66

A solution of Carrageenan (INCI name CARRAGEENAN) (0.6 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is precipitated with 4 volumes of ethanol, and is then centrifuged. The solid obtained is dried in a vacuum oven at 50 °C.

The composite material C2 is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2.C3: Synthesis by precipitation/centrifugation of materials bismuth oxycarbonate/carrageenan composites, with a mass ratio of 1 , 66

A solution of Carrageenan (INCI name CARRAGEENAN) (0.6 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is precipitated with 4 volumes of ethanol, and is then centrifuged. The solid obtained is dried in a vacuum oven at 50 °C.

The C3 composite material is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2.C4: Synthesis by precipitation/centrifugation of materials bismuth oxycarbonate/carrageenan composites, with a mass ratio of 1 , 66

A solution of Carrageenan (INCI name CARRAGEENAN) (0.6 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is precipitated with 10 volumes of ethanol, and is then centrifuged. The solid obtained is dried in a vacuum oven at 50 °C.

The C4 composite material is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2.D: Synthesis by atomization, of materials bismuth oxycarbonate/carrageenan composites, with a mass ratio of 1 , 66

A solution of Carrageenan (INCI name CARRAGEENAN) (0.6 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to Example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then atomized at 150 °C, with a pump flow rate of 15%, a suction flow rate of 80% and a number of Noddles of 5 (Device type: Mini-Atomizer B-290 BUCHI).

Composite material D is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2.E1: Synthesis by freeze-drying, of materials bismuth oxycarbonate/carrageenan composites, with a mass ratio of 1 , 66

A solution of Carrageenan (INCI name CARRAGEENAN) (0.6 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then lyophilized.

The composite material E1 is isolated as a white solid and is characterized by UV/Vis spectrophotometry.

Example 2.E2: Synthesis by freeze-drying, of composite materials Bismuth oxycarbonate/Carrageenan, mass ratio equal to 4 , 16

A solution of Carrageenan (INCI name CARRAGEENAN) (0.24 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then lyophilized.

The composite material E2 is isolated as a white solid and is characterized by UV/Vis spectrophotometry.

Example 2.F1: Synthesis by centrifugation, of composite materials Bismuth oxycarbonate/Carrageenan, with a mass ratio equal to 1.66

A solution of Carrageenan (INCI name CARRAGEENAN) (0.6 g) in 100 ml of water is stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to Example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then centrifuged, washed with ethanol and centrifuged again. The solid obtained is dried in a vacuum oven at 50 °C.

The composite material F1 is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2.F2: Synthesis by precipitation/centrifugation, of composite materials Bismuth oxycarbonate/Carrageenan, with a mass ratio equal to 1.66

A solution of Carrageenan (INCI name CARRAGEENAN) (0.6 g) in 100 ml of water is stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is precipitated with 4 volumes of ethanol, and is then centrifuged. The solid obtained is dried in a vacuum oven at 50 °C.

The composite material F2 , is isolated in the form of white powder and is characterized by UV/Vis spectrophotometry.

Example 2.G: Synthesis by atomization, of composite materials Bismuth oxycarbonate/Calcium Lignosulfonate, with a mass ratio equal to 0.71

A solution of Calcium Lignosulfonate (DP25228, marketed by Borregaard) (1.4 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to Example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The light beige dispersion is then atomized at 120 °C, with a pump flow rate of 15%, a suction flow rate of 80% and a number of Noddles of 5 (Device type: BUCHI B-290 Mini-Atomizer).

Composite material G is isolated as a beige powder and is characterized by UV/Vis spectrophotometry.

Example 2.H1: Synthesis by freeze-drying, of composite materials Bismuth oxycarbonate/Calcium Lignosulfonate, with a mass ratio equal to 0.71

A solution of Calcium Lignosulfonate (DP25228, marketed by Borregaard) (1.4 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The light beige dispersion is then freeze-dried.

The composite material H1 is isolated as a cottony white solid and is characterized by UV/Vis spectrophotometry.

Example 2.H2: Synthesis by freeze-drying, of composite materials Bismuth oxycarbonate/Calcium Lignosulfonate, with a mass ratio equal to 1.78 .

A solution of Calcium Lignosulfonate (DP25228, marketed by Borregaard) (0.56 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The light beige dispersion is then freeze-dried.

The H2 composite material is isolated as a cottony white solid and is characterized by UV/Vis spectrophotometry.

Example 2.I: Synthesis by atomization, of composite materials Bismuth oxycarbonate/Sodium Lignosulfonate, with a mass ratio equal to 0.71 .

A solution of Sodium Lignosulfonate (DP25230, marketed by Borregaard) (1.4 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to Example 1B, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The light beige dispersion is then atomized at 120 °C, with a pump flow rate of 15%, a suction flow rate of 80% and a number of Noddles of 5 (Device type: BUCHI B-290 Mini-Atomizer).

Composite material I is isolated as a beige powder and is characterized by UV/Vis spectrophotometry.

Example 2.J1: Synthesis by freeze-drying, of composite materials Bismuth oxycarbonate/Sodium Lignosulfonate, with a mass ratio equal to 0.71

A solution of Sodium Lignosulfonate (DP25230, marketed by Borregaard) (1.4 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1B, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The light beige dispersion is then freeze-dried.

The composite material J1 is isolated as a cottony white solid and is characterized by UV/Vis spectrophotometry.

Example 2.J2: Synthesis by freeze-drying, of composite materials Bismuth oxycarbonate/Sodium Lignosulfonate, with a mass ratio equal to 1.78

A solution of Sodium Lignosulfonate (DP25230, marketed by Borregaard) (0.56 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1B, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The light beige dispersion is then freeze-dried.

The composite material J2 is isolated as a cottony white solid and is characterized by UV/Vis spectrophotometry.

Example 2.K: Synthesis by atomization, of composite materials Bismuth oxycarbonate/Chitosan, mass ratio equal to 0.6

A solution of Chitosan (Kiosmetin-CSG marketed by Kitozyme) (1.64 g) in 100 ml of water is adjusted to pH 4 with lactic acid, then stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to Example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The light beige dispersion is then atomized at 160 °C, with a pump flow rate of 15%, a suction flow rate of 80% and a number of Noddles of 5 (Device type: BUCHI B-290 Mini-Atomizer).

The composite material K is isolated as a beige powder and is characterized by UV/Vis spectrophotometry.

Example 2.L1: Synthesis by freeze-drying, of composite materials bismuth oxycarbonate/Chitosan, with a mass ratio equal to 0.6

A solution of Chitosan (Kiosmetin-CSG marketed by Kitozyme) (1.64 g) in 100 ml of water is adjusted to pH 4 with lactic acid, then stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1B, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The light beige dispersion is then freeze-dried.

The composite material L1 is isolated as a beige powder and is characterized by UV/Vis spectrophotometry.

Example 2.L2: Synthesis by freeze-drying, of composite materials bismuth oxycarbonate/Chitosan, with a mass ratio equal to 1.51

A solution of Chitosan (Kiosmetin-CSG marketed by Kitozyme) (0.66 g) in 100 ml of water is adjusted to pH 4 with lactic acid, then stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1B, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The light beige dispersion is then freeze-dried.

The composite material L2 is isolated as a beige powder and is characterized by UV/Vis spectrophotometry.

Example 2.M: Synthesis by atomization, of composite materials Bismuth oxycarbonate/Sodium Alginate, with a mass ratio equal to 1.06

A solution of Sodium Alginate (0.94 g) in 100 ml of water is heated to 40 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then atomized at 160 °C, with a pump flow rate of 15%, a suction flow rate of 80% and a number of Noddles of 2 (Device type: Mini-Atomizer B-290 BUCHI).

Composite material M is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2.N1: Synthesis by freeze-drying, of composite materials Bismuth oxycarbonate/Sodium Alginate, with a mass ratio equal to 1.06

A solution of Sodium Alginate (0.94 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then lyophilized.

The composite material N1 is isolated as a cottony white solid and is characterized by UV/Vis spectrophotometry.

Example 2.N2: Synthesis by freeze-drying, of composite materials Bismuth oxycarbonate/Sodium Alginate, with a mass ratio equal to 2.7

A solution of sodium alginate (0.37 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then lyophilized.

The N2 composite material is isolated as a cottony white solid and is characterized by UV/Vis spectrophotometry.

Example 2.O1: Synthesis by isolation (centrifugation), of composite materials Bismuth oxycarbonate/Sodium Alginate, with a mass ratio equal to 1.06

A solution of Sodium Alginate (0.94 g) in 100 ml of water is stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to Example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then centrifuged, washed with ethanol and centrifuged again. The solid obtained is dried in a vacuum oven at 50 °C.

The composite material O1 is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2.O2: Synthesis by centrifugation, of composite materials Bismuth oxycarbonate/Sodium Alginate, with a mass ratio equal to 1.06

A solution of Sodium Alginate (0.94 g) in 100 ml is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to Example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is heated to 55 °C for 1 h 30 and allowed to return to room temperature, then centrifuged, washed with ethanol and centrifuged again. The solid obtained is dried in a vacuum oven at 50 °C.

The O2 composite material is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2.P1: Synthesis by atomization, of composite materials Bismuth oxycarbonate/Dextran Sodium Sulfate, mass ratio equal to 0 , 9

A solution of Dextran Sodium Sulfate (Dextralip 10C, marketed by Safic-Alcan) (1.1 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1B, the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion is then atomized at 120 °C, with a pump flow rate of 15%, a suction flow rate of 80% and a number of Noddles of 4 (Device type: Mini-Atomizer B-290 BUCHI).

The composite material P1 is isolated in the form of beige powder and is characterized by UV/Vis spectrophotometry.

Example 2.P2: Synthesis by atomization, of composite materials Bismuth oxycarbonate/Dextran Sodium Sulfate, mass ratio equal to 8 , 33

A solution of Dextran Sodium Sulfate (Dextralip 10C, marketed by Safic-Alcan) (0.12 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1B, the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion is then atomized at 120 °C, with a pump flow rate of 15%, a suction flow rate of 80% and a number of Noddles of 2 (Device type: Mini-Atomizer B-290 BUCHI).

The composite material P2 is isolated in the form of beige powder and is characterized by UV/Vis spectrophotometry.

Example 2.Q1: Synthesis by freeze-drying, of composite materials Bismuth oxycarbonate/Dextran Sodium Sulfate, mass ratio equal to 0 , 9

A solution of Dextran Sodium Sulfate (Dextralip 10C, marketed by Safic-Alcan) (1.1 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1B, the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion is then freeze-dried.

The composite material Q1 is isolated as a cottony white solid and is characterized by UV/Vis spectrophotometry.

Example 2.Q2: Synthesis by freeze-drying, of composite materials Bismuth oxycarbonate/Dextran Sodium Sulfate, mass ratio equal to 2 , 27

A solution of Dextran Sodium Sulfate (Dextralip 10C, marketed by Safic-Alcan) (0.44 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1B, the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion is then freeze-dried.

The composite material Q2 is isolated as a cottony white solid and is characterized by UV/Vis spectrophotometry.

Example 2.R: Synthesis by atomization, of composite materials Bismuth oxycarbonate/Polyvinyl Alcohol, mass ratio equal to 0 , 84

A solution of Polyvinyl alcohol (Mowiol 8-88 marketed by Sigma Aldrich) (1.19 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1B, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then atomized at 120 °C, with a pump flow rate of 15%, a suction flow rate of 80% and a number of Noddles of 3 (Device type: Mini-Atomizer B-290 BUCHI).

The composite material R is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2.S1: Synthesis by freeze-drying of composite materials Bismuth oxycarbonate/Polyvinyl Alcohol, mass ratio equal to 0 , 84

A solution of Polyvinyl alcohol (Mowiol 8-88 marketed by Sigma Aldrich) (1.19 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1B, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is freeze-dried.

The composite material S1 is isolated as a cottony white solid and is characterized by UV/Vis spectrophotometry.

Example 2.S2: Synthesis by freeze-drying, of composite materials Bismuth oxycarbonate/Polyvinyl Alcohol, mass ratio equal to 2 , 12

A solution of Polyvinyl alcohol (Mowiol 8-88 marketed by Sigma Aldrich) (0.47 g) in 100 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1B, then the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then lyophilized.

The composite material S2 is isolated as a cottony white solid and is characterized by UV/Vis spectrophotometry.

Example 2.T: Synthesis by precipitation/centrifugation, of composite materials Bismuth oxycarbonate/Polyhydroxystearic acid, mass ratio equal to 2 , 12

A solution of polyhydroxystearic acid (INCI name: POLYHYDROXYSTEARIC ACID) (0.84 g) in 50 ml of acetone is heated to 50 °C and stirred until the polymer is completely dissolved.

A suspension of 1 g of bismuth oxycarbonate particles according to Example 1B, in 50 ml of acetone, is subjected to ultrasound for 15 min, then is added to the polymer solution at 50 °C and is then stirred overnight at room temperature. The white dispersion obtained is then centrifuged. The pellet is washed with acetone and is centrifuged again. The solid obtained is dried in a vacuum oven at 50 °C. The white dispersion obtained is then lyophilized.

The composite material T is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2.U: Synthesis by freeze-drying, of composite materials bismuth oxycarbonate not compliant with ’ invention/Dextran sodium sulfate, with a mass ratio equal to 0 , 9

A solution of Dextran Sodium Sulfate (Dextralip 10C, marketed by Safic-Alcan) (1.1 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles not in accordance with the invention (length 500 nm, thickness 50 nm). The suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion is then lyophilized.

The composite material U is isolated as a cottony white solid and is characterized by UV/Vis spectrophotometry.

Example 2.V: Synthesis by freeze-drying, of composite materials bismuth oxycarbonate / Distarch phosphate of ma ï s pregelatinized hydroxypropyl, with a mass ratio of 1 , 1

A solution of pregelatinized hydroxypropyl corn distarch phosphate (INCI name: HYDROXYPROPYL STARCH PHOSPHATE) (0.93 g) in 100 ml of water is heated to 95 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is freeze-dried.

Composite material V, is isolated as a cottony beige solid and is characterized by UV/Vis spectrophotometry.

Example 2.W – Synthesis by lyophilization of composite particles of bismuth oxycarbonate/distarch phosphate ï s pregelatinized hydroxypropyl, with a mass ratio of 2 , 7

A solution of pregelatinized hydroxypropyl corn distarch phosphate (INCI name: HYDROXYPROPYL STARCH PHOSPHATE) (0.37 g) in 100 ml of water is heated to 95 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is freeze-dried.

The composite material W, is isolated as a cottony beige solid and is characterized by UV/Vis spectrophotometry.

Example 2.X – Synthesis by atomization of composite particles of bismuth oxycarbonate/Pullulan, with a mass ratio equal to 0 , 71

A solution of Pullulan (marketed by HAYASHIBARA) (1.4 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to Example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then atomized at 130 °C, with a pump flow rate of 15%, a suction flow rate of 80% and a number of Noddles of 2 (Device type: BUCHI B-290 Mini-Atomizer).

Composite material X, is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2.Y – Synthesis by lyophilization of composite particles of bismuth oxycarbonate/Pullulan, with a mass ratio equal to 0 , 71

A solution of Pullulan (marketed by HAYASHIBARA) (1.4 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is freeze-dried.

The composite material Y, is isolated as a cottony white solid and is characterized by UV/Vis spectrophotometry.

Example 2.Z – Synthesis by lyophilization of composite particles of bismuth oxycarbonate/Pullulan, with a mass ratio equal to 1 , 78

A solution of Pullulan (marketed by HAYASHIBARA) (0.56g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is freeze-dried.

The composite material Z, is isolated as a cottony white solid and is characterized by UV/Vis spectrophotometry.

Example 2. AA - Synthesis by centrifugation of composite particles of bismuth oxycarbonate/Myristoyl pullulan, with a mass ratio equal to 0 , 71

A solution of Myristoyl pullulan (marketed by Katakura Chikkarin) (1.4 g) in 100 ml of isododecane is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to Example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is centrifuged, washed with ethanol and centrifuged again. The solid obtained is dried in a vacuum oven at 50 °C.

The AA composite material is isolated as a white powder and is characterized by UV/Vis spectrophotometry.

Example 2. DD – Synthesis by atomization of composite particles of bismuth oxycarbonate/hydrolyzed soy protein, with a mass ratio of 2

A solution of soy protein (INCI Hydrolyzed soy protein) (0.5 g) in 100 ml of water is stirred until the polymer is completely dissolved.

To this solution is added 1 g of bismuth oxycarbonate particles according to Example 1A, and the suspension is subjected to ultrasound for 15 min, then stirred overnight. The white dispersion obtained is then atomized at 150 °C, with a pump flow rate of 15%, a suction flow rate of 80% and a number of Noddles of 9 (Device type: Mini-Atomizer B-290 BUCHI).

The DD composite material is isolated in the form of white powder and is characterized by UV/Vis spectrophotometry.

Example 2. EE : Association of bismuth oxycarbonate particles with the polymer Sodium Lignosulfonate of mass ratio equal to 0.71

A solution of Sodium Lignosulfonate (DP25230, marketed by Borregaard) (14 mg) in 10 ml of water is stirred until the polymer is completely dissolved.

To this solution are added 10 mg of bismuth oxycarbonate particles according to example 1B, and the suspension is subjected to ultrasound for 15 minutes, then stirred overnight.

The EE product is characterized by UV/Vis spectrophotometry.

Example 2. FF : Association of bismuth oxycarbonate particles with the polymer Carrageenan of mass ratio equal to 1.66

A solution of Carrageenan (INCI name CARRAGEENAN) (6 mg) in 10 ml of water is heated to 80 °C and stirred until the polymer is completely dissolved. The medium is then cooled to room temperature.

To this solution are added 10 mg of bismuth oxycarbonate particles according to example 1A, and the suspension is subjected to ultrasound for 15 minutes, then stirred overnight.

The FF product is characterized by UV/Vis spectrophotometry.

Example 2. : Summary of the synthesis conditions of materials A to FF

Table 1 below summarizes all the products prepared in Examples 2.A1 to 2.FF.

Composite or Product Method Bismuth Oxycarbonate/Polymer Composite Particles Mass ratio A1 Atomization (BiO) ₂ CO ₃ /Carrageenan 1.66 A2 Atomization (BiO) ₂ CO ₃ /Carrageenan 0.5 B1 Freeze drying (BiO) ₂ CO ₃ /Carrageenan 1.66 B2 Freeze drying (BiO) ₂ CO ₃ /Carrageenan 4.16 C1 Centrifugation (BiO) ₂ CO ₃ /Carrageenan 1.66 C2 Precipitation/Centrifugation (BiO) ₂ CO ₃ /Carrageenan 1.66 C3 Precipitation/Centrifugation (BiO) ₂ CO ₃ /Carrageenan 1.66 C4 Precipitation/Centrifugation (BiO) ₂ CO ₃ /Carrageenan 1.66 D Atomization (BiO) ₂ CO ₃ /Carrageenan 1.66 E1 Freeze drying (BiO) ₂ CO ₃ /Carrageenan 1.66 E2 Freeze drying (BiO) ₂ CO ₃ /Carrageenan 4.16 F1 Centrifugation (BiO) ₂ CO ₃ /Carrageenan 1.66 F2 Precipitation/Centrifugation (BiO) ₂ CO ₃ /Carrageenan 1.66 G Atomization (BiO) ₂ CO ₃ /Ca lignosulfonate 0.71 H1 Freeze drying (BiO) ₂ CO ₃ /Ca lignosulfonate 0.71 H2 Freeze drying (BiO) ₂ CO ₃ @Ca lignosulfonate 1.78 I Atomization (BiO) ₂ CO ₃ /Na lignosulfonate 0.71 D1 Freeze drying (BiO) ₂ CO ₃ /Na lignosulfonate 0.71 J2 Freeze drying (BiO) ₂ CO ₃ /Na lignosulfonate 1.78 K Atomization (BiO) ₂ CO ₃ /Chitosan 0.6 L1 Freeze drying (BiO) ₂ CO ₃ /Chitosan 0.6 L2 Freeze drying (BiO) ₂ CO ₃ /Chitosan 1.51 M Atomization (BiO) ₂ CO ₃ /Sodium alginate 1.06 N1 Freeze drying (BiO) ₂ CO ₃ /Sodium alginate 1.06 N2 Freeze drying (BiO) ₂ CO ₃ /Sodium alginate 2.7 O1 Centrifugation (BiO) ₂ CO ₃ /Sodium alginate 1.06 O2 Centrifugation (BiO) ₂ CO ₃ /Sodium alginate 1.06 P1 Atomization (BiO) ₂ CO ₃ /Dextran Sodium sulfate 0.9 P2 Atomization (BiO) ₂ CO ₃ /Dextran Sodium sulfate 8.33 Q1 Freeze drying (BiO) ₂ CO ₃ /Dextran Sodium sulfate 0.9 Q2 Freeze drying (BiO) ₂ CO ₃ /Dextran Sodium sulfate 2.27 R Atomization (BiO) ₂ CO ₃ /Polyvinyl Alcohol 0.84 S1 Freeze drying (BiO) ₂ CO ₃ /Polyvinyl Alcohol 0.84 S2 Freeze drying (BiO) ₂ CO ₃ /Polyvinyl Alcohol 2.12 T Precipitation/Centrifugation (BiO) ₂ CO ₃ /Polyhydroxystearic acid 2.12 U Freeze drying (BiO) _2CO3 /Dextran sodium sulfate with (BiO _{) 2CO3} non _- compliant 0.9 V Freeze drying (BiO _{) 2CO3} / Pregelatinized hydroxypropyl corn distarch phosphate 1.1 W Freeze drying (BiO _{) 2CO3} / Pregelatinized hydroxypropyl corn distarch phosphate 2.7 X Atomization (BiO) ₂ CO ₃ /Pullulan 0.71 Y Freeze drying (BiO) ₂ CO ₃ /Pullulan 0.71 Z Freeze drying (BiO) ₂ CO ₃ /Pullulan 1.78 AA Centrifugation (BiO) ₂ CO ₃ /Myristoyl Pullulan 0.71 DD Atomization (BiO) _{2CO3 /} Hydrolyzed soy protein 2 EE Association (BiO) ₂ CO ₃ + Na lignosulfonate 0.71 FF Association (BiO) ₂ CO ₃ + Carrageenan 1.66

Example 3: Spectra of ’ absorbance of composite materials and products ’ association of ’ bismuth oxycarbonate

The absorbance spectra by UV-visible spectrophotometry of the composite materials in accordance with the invention and prepared according to example 2 were carried out.

They were obtained by UV-visible spectrophotometry on dispersions at 0.005% by mass of composite in water, or in a water/propylene glycol/polysorbate 20 (Tween 20) mixture of respective mass fractions 49.85/49.85/0.30 for composite materials R, S1, S2 and T and AA.

The quartz cell used for absorbance measurements is 1 cm on each side. The spectrophotometer used is the Genesys 10S from Thermo Fischer Scientific.

Preparation of dispersions

Aqueous dispersions of bismuth oxycarbonate/polymer composite materials at 0.1% by mass of bismuth oxycarbonate are exposed to ultrasound for 2 to 15 minutes and then stirred with a magnetic stirrer for 16 h. The suspensions are then diluted to 0.005% by mass of bismuth oxycarbonate and stirred again under magnetic stirring for 20 min before performing the absorbance measurement.

Beyond a predetermined threshold value of UV absorbance measurement, the filtration of UV radiation is considered effective. In particular, composite materials having a UV absorbance threshold, in the dispersion medium comprising said composite materials at a mass fraction of 0.005%, greater than 0.25 are considered effective for the filtration of UV radiation.

The absorbance spectra are shown in Figures 1 to 15.

The results are grouped in the following Table 2.

Absorbance Composite A1 Composite A2 Composite B1 Composite B2 Composite C1 Composite C2 Absorbance at 220 nm 0.8 0.38 0.48 0.5 0.84 0.56 Absorbance at 300 nm 0.96 0.42 0.5 0.58 0.98 0.68 Absorbance at 400 nm 0.48 0.24 0.34 0.36 0.68 0.46 Absorbance at 620 nm 0.12 0.1 0.16 0.12 0.24 0.16 Absorbance Composite C3 Composite C4 Composite D Composite E1 Composite E2 Composite F1 Absorbance at 220 nm 0.72 0.68 0.68 0.5 0.52 0.59 Absorbance at 300 nm 0.84 0.8 0.8 0.56 0.64 0.68 Absorbance at 400 nm 0.56 0.52 0.42 0.36 0.44 0.42 Absorbance at 620 nm 0.18 0.18 0.12 0.16 0.16 0.18 Absorbance Composite F2 Composite G Composite H1 Composite H2 Composite I Composite J1 Absorbance at 220 nm 0.84 2.7 2.5 1.7 2.65 2.6 Absorbance at 300 nm 0.98 1.2 1 1.15 1.35 1.35 Absorbance at 400 nm 0.56 0.5 0.5 0.45 0.45 0.5 Absorbance at 620 nm 0.22 0.1 0.2 0.1 0.08 0.12 Absorbance Composite J2 Composite K Composite L1 Composite L2 Composite M Composite N1 Absorbance at 220 nm 1.55 0.74 0.72 0.66 0.48 0.52 Absorbance at 300 nm 1.1 0.8 0.78 0.72 0.52 0.6 Absorbance at 400 nm 0.5 0.32 0.32 0.32 0.32 0.36 Absorbance at 620 nm 0.12 0.08 0.08 0.08 0.12 0.12 Absorbance Composite N2 Composite O1 Composite O2 Composite P1 Composite P2 Composite Q1 Absorbance at 220 nm 0.48 0.84 1.14 1.04 0.46 0.72 Absorbance at 300 nm 0.48 0.96 1.36 1.16 0.52 0.86 Absorbance at 400 nm 0.28 0.52 0.78 0.44 0.28 0.48 Absorbance at 620 nm 0.12 0.2 0.3 0.08 0.12 0.16 Absorbance Composite Q2 Composite R Composite S1 Composite S2 Composite T Composite U Absorbance at 220 nm 0.64 0.72 0.76 0.72 0.4 0.1 Absorbance at 300 nm 0.74 0.84 0.9 0.84 0.46 0.11 Absorbance at 400 nm 0.4 0.32 0.36 0.36 0.38 0.1 Absorbance at 620 nm 0.16 0.08 0.08 0, 0.2 0.08 Absorbance Bismuth Alfa Aesar Composite V Composite W Composite X Composite Y Composite Z Absorbance at 220 nm 0.01 0.40 0.35 0.50 0.62 0.32 Absorbance at 300 nm 0 0.46 0.40 0.60 0.70 0.40 Absorbance at 400 nm 0.03 0.38 0.34 0.48 0.40 0.28 Absorbance at 620 nm 0.04 0.18 0.16 0.22 0.10 0.10 Absorbance Composite AA Composite DD Absorbance at 220 nm 1.34 1.40 Absorbance at 300 nm 1.64 1.80 Absorbance at 400 nm 1.05 0.58 Absorbance at 620 nm 0.40 0.16

The composite materials in accordance with the invention show good absorbance of UV rays and consequently effective filtration of UV rays, and in particular of the UV-B range. On the contrary, the comparative composite materials show low absorbance, and do not allow sufficient filtering of the entire UV range.

The absorbance spectra also show that the composite materials according to the invention have a high transparency in the visible range between 400 and 780 nm.

Example 4: Kinetics of ’ absorption of composite materials composed of particles of ’ bismuth oxycarbonate and d ’ a polymer, and ’ association of particles ’ bismuth oxycarbonate with this same polymer at the same mass ratio

The kinetics of absorption of materials composites composed of bismuth oxycarbonate particles and a polymer, and the association of bismuth oxycarbonate particles with this same polymer at the same mass ratio is studied for t = 0 and t = 48 h at 45 °C, on dispersions at 0.005% by mass in bismuth oxycarbonate in water.

The absorbance spectra are obtained by UV-visible spectrophotometry following the protocol described in example 3, and are presented in figures 16 and 17.

The results are grouped in the following Table 3.

Absorbance Composite I at t = 0 Composite I at t = 48h and T = 45°C EE product at t = 0 EE product at t = 48 h and T = 45 °C Sodium Lignosulfonate Absorbance at 220 nm 2.6 2.6 2.6 2.6 1.6 Absorbance at 300 nm 1.25 1.25 1.25 1.25 0.18 Absorbance at 400 nm 0.4 0.4 0.4 0.4 0 Absorbance at 620 nm 0.1 0.1 0.1 0.1 0 Absorbance Composite D at t = 0 Composite D at t = 48 h and T = 45 °C Product FF at t = 0 FF product at t = 48 h and T = 45 °C Absorbance at 220 nm 0.76 0.9 0.34 0.67 Absorbance at 300 nm 0.9 1.04 0.4 0.72 Absorbance at 400 nm 0.46 0.54 0.32 0.46 Absorbance at 620 nm 0.12 0.14 0.16 0.2

The composite materials according to the invention show good absorbance of UV rays at t = 0 and t = 48 h, and at 45 °C, and consequently effective filtration of UV rays, and in particular of the UV-B range. On the contrary, the comparative products do not allow sufficient filtering of the entire UV range.

Claims (19)

Composite material comprising:

1. at least one particle of bismuth oxycarbonate of formula (I) (BiO) _{2- x} (CO ₃ ), as well as its solvates such as hydrates, in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm; and
2. at least one polymer.

Composite material according to claim 1, characterized in that it has an average size of the largest particle dimension of composite material less than or equal to 1 µm, and more preferably less than or equal to 500 nm, even more preferably less than or equal to 450 nm. Composite material according to any one of the preceding claims, the mass ratio of bismuth oxycarbonate particle(s) a) to polymer(s) b) varying from 0.01 to 50, preferably from 0.2 to 15, more preferably from 0.3 to 10, and more preferably from 0.5 to 8.5. Composite material according to any one of the preceding claims, comprising:

• a core comprising at least a) at least one particle of bismuth oxycarbonate of formula (I) (BiO) _{2- x} (CO ₃ ), as well as its solvates such as hydrates, in which -0.4 < x < 0.6, the largest average dimension of said particles is less than 400 nm, and
• at least one layer continuously or discontinuously surrounding said core and comprising b) at least one polymer.

Composite material according to the preceding claim, the molar ratio between the number of moles of coating compound(s) and the number of moles of core compound(s) varying from 0.0001 to 20, preferably varying from 0.005 to 15, more preferably varying from 0.01 to 10, and even more preferably varying from 0.05 to 5. Composite material according to any one of the preceding claims, said bismuth oxycarbonate particles being crystallized. Composite material according to any one of the preceding claims, said bismuth oxycarbonate particles being of formula (BiO) ₂ (CO ₃ ), as well as its solvates such as hydrates. Composite material according to any one of the preceding claims, said bismuth oxycarbonate particles being in the form of tubes, platelets and/or rods, preferably in the form of platelets and/or rods. Composite material according to any one of the preceding claims, said polymer(s) b) being non-ionic, anionic or cationic, preferably non-ionic or anionic, more particularly being chosen from polyethylene glycols, polyethylene amines, polypropylene glycols, polyvinyl alcohols, polyacrylic acids and their salts, polymethacrylic acids and their salts, polymethylmethacrylates, polyvinyl sulfonates, polystyrene sulfonates, polylactic acids and their salts, polycaprolactones, polyglycolic acids, polyacetoacetates, poly(lactic-co-glycolic) acids, celluloses and their derivatives, alginic acids and their salts, carrageenans, starches, pectins, inulins, dextrans and their derivatives, gum xanthan, ulvans, lignosulfonates and their salts, chitins and chitosans, pullulans, polyvinyl alcohols and polyhydroxystearic acid, and/or their copolymers, or mixtures thereof. Composite material according to any one of the preceding claims, said polymer(s) b) being chosen from:

• lignosulfonic acid, lignosulfonates, polystyrene sulfonics, polystyrene sulfonates, anionic polyanethol derivatives, in particular polyanethol sulfonates, and mixtures thereof,
• alkyl esters or ethers of polyols, in particular glycerol,
• anionic polysaccharides, preferably chosen from sulfated polysaccharides, in particular ulvans, dextran sulfates, carrageenans, and mixtures thereof, and carboxylate polysaccharides, in particular alginates,
• cationic polysaccharides, preferably chosen from polysaccharides with amine groups, in particular chitosans,
• modified polysaccharides, in particular chosen from polysaccharide esters, and preferably from pullulan esters,
• poly(alkylene (C ₂ -C ₅ )imines), and preferably among polyethyleneimines and polypropyleneimines, in particular poly(ethyleneimine),
• polyamino acids, and preferably among proteins,
• anionic acyclic polymers, bearing carboxylic groups or carboxylates of alkali or alkaline earth metals such as sodium, and chosen from homo or copolymers of (meth)acrylic acid, preferably from sodium polymethacrylates and copolymers of (meth)acrylic acid with alkyl (poly)ether (meth)acrylates, in particular copolymers of (meth)acrylic acid and POE/POP (meth)acrylate, and
• - their mixtures.

Composite material according to any one of the preceding claims, said polymer(s) b) being chosen from:

• lignosulfonates, in particular of alkali or alkaline earth metals such as sodium or calcium lignosulfates,
• carrageenans,
• chitosans,
• alginates, particularly of alkali or alkaline-earth metals such as sodium alginate,
• dextrans, in particular of alkali or alkaline earth metals, and dextrans sulfates of alkali or alkaline earth metals such as sodium dextran sulfate,
• polyhydroxystearic acids,
• starches and their derivatives, particularly phosphates such as hydroxypropyl corn distarch phosphate,
• pullulans and their ester derivatives, in particular of _C1 - _C30 , preferably _C10 - _C20, carboxylic acids, such as myristoyl pullulan,
• polyvinyl alcohols,
• optionally hydrolyzed proteins such as optionally hydrolyzed soy proteins, and
• their mixtures.

Process for preparing a composite material according to any one of the preceding claims, comprising at least the steps consisting of:

1. having at least one particle of bismuth oxycarbonate a) of formula (I) (BiO) _{2- x} (CO ₃ ), formula (I) as well as its solvates such as hydrates, in which -0.4 < x < 0.6, the largest average dimension of said particles being less than 400 nm, optionally dispersed in at least one solvent or mixture of solvents A;
2. have a solution of at least one polymer b), optionally in a solvent or mixture of solvents B;
3. bringing together said at least one particle (a) or dispersion (i) and said solution (ii) to form the composite material;
4. isolate said composite material.

Preparation process according to the preceding claim, said solvent(s) A and/or B are chosen from apolar aprotic solvents, polar and protic solvents, more preferably from water, alcohols, polyols and their mixtures. Preparation process according to any one of claims 12 or 13, further comprising one or more separation steps, in particular by centrifugation and/or by filtration, in particular ultrafiltration, and/or by freeze-drying and/or by atomization. Composition, in particular cosmetic, comprising at least one composite material according to any one of claims 1 to 11. Composition according to the preceding claim comprising at least:
i) at least one composite material according to any one of claims 1 to 11;
ii) at least one aqueous phase and/or at least one fatty phase; and
iii) at least one compound chosen from: 1) UV filters distinct from composite materials i); 2) coloring matters; 3) cosmetic active ingredients for the care of keratin materials; 4) surfactants; 5) thickeners; and mixtures thereof. Composition according to any one of claims 15 or 16, said composite materials being present in a content ranging from 0.5% to 70% by weight, preferably from 1% to 50% by weight, even better from 2% to 40% by weight, relative to the total weight of the composition. Non-therapeutic cosmetic use of a composite material according to any one of claims 1 to 11, for filtering UV radiation, preferably UV-B, comprising at least the application to keratin materials of a composition comprising a composite material according to any one of claims 1 to 11. Non-therapeutic cosmetic process for filtering UV radiation, preferably UV-B, comprising at least the application to keratin materials of a composition comprising a composite material according to any one of claims 1 to 11.