Hybrid polymers and their applications

Abstract

The present invention relates to hybrid polymers obtained by a free radical precipitation polymerization method from at least one monomer containing at least one unsaturated ethylenic functional group in the presence of at least one protein. The present invention also relates to the use of said hybrid polymers as thickeners in various formulations or compositions.

Description

[Technical Field]

[0001] The present invention belongs to the technical field of hybrid polymers. More precisely, the subject of the present invention is a hybrid polymer obtained by a free radical precipitation polymerization method from at least one monomer containing at least one unsaturated ethylenic functional group in the presence of at least one protein. The present invention also relates to the use of said hybrid polymer as a thickener in various formulations or compositions. [Background technology]

[0002] Synthetic polymers have been used for many years as thickening agents to increase the viscosity of various aqueous formulations in a variety of applications.

[0003] These polymers have unparalleled application performance qualities, but are made from 100% fossil resources. Recently, due to increasing demand and a shortage of crude oil reserves, a shortage of monomers to produce these synthetic polymers has been observed. Therefore, there is a need to replace these synthetic polymers with hybrid polymers that are obtained, at least in part, from renewable natural resources. These hybrid polymers retain optimal application properties.

[0004] Grafting of monomers onto natural materials such as sugars and starches has been described in the literature. For example, U.S. Patent Nos. 5,854,191, 5,223,171, 5,227,446, and 5,296,470 disclose the use of graft copolymers in cleaning applications. Patents WO2018 / 108663, WO2018 / 108665, and WO2018 / 108667 describe the use of such hybrids in cosmetic compositions.

[0005] These hybrid thickening polymers are excellent alternatives, but their use is limited to certain application areas: they are not suitable for applications with more difficult experimental conditions, such as petroleum applications, which require the polymer to withstand high temperatures. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 5,854,191 [Patent Document 2] U.S. Patent No. 5,223,171 [Patent Document 3] U.S. Patent No. 5,227,446 [Patent Document 4] U.S. Patent No. 5,296,470 [Patent Document 5] WO2018 / 108663 [Patent Document 6] WO2018 / 108665 [Patent Document 7] WO2018 / 108667 [Patent Document 8] WO2020 / 094960A1 [Patent Document 9] WO2021 / 123599 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, it is essential to develop a general-purpose thickener that satisfies the application characteristics expected in various application fields. [Means for solving the problem]

[0008] Unexpectedly, the Applicant Company has developed hybrid polymers obtained by free radical precipitation polymerization that overcome the above-mentioned drawbacks.

[0009] The present application relates to hybrid polymers obtained by a free radical precipitation polymerization method between at least one monomer containing at least one unsaturated ethylenic functional group, in the presence of at least one protein.

[0010] More specifically, the present invention relates to a hybrid polymer (HP) in particulate form, which is obtained by a free radical precipitation polymerization process, which comprises the following successive steps: (A) - 50% to 95% by weight of at least one polar solvent, - 4% to 40% by weight of at least one monomer containing at least one unsaturated ethylenically functional group, and - 0.1% to 40% by weight of at least one protein preparing a solution (S1) comprising: (B) initiating polymerization in solution (S1) to obtain a dispersion (D1) comprising at least one hybrid polymer (HP), said polymer (HP) precipitating in the polymerization solvent; (C) separating the hybrid polymer (HP) in particulate form from the dispersion (D1); by.

[0011] The present invention also relates to the use of said hybrid polymers (HP) as thickeners.The present invention also relates to viscosity modifiers comprising at least one hybrid polymer (HP) according to the invention. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 shows the NMR / DOSY spectrum of serum proteins alone. [Figure 2] FIG. 1 shows the NMR / DOSY spectrum of a hybrid polymer (HP). DETAILED DESCRIPTION OF THE INVENTION

[0013] Definitions and Generalities Throughout this application, the following definitions apply unless otherwise stated.

[0014] All intervals are inclusive and combinable. Value ranges include the lower and upper limits. Thus, the value ranges "between 0.1 and 1.0" and "0.1 and 1" include the values ​​0.1 and 1.0. The number of significant digits does not constitute a limit on the displayed quantity or the precision of the data.

[0015] As used herein, the term "hydrophilic monomer" refers to a monomer that has an octanol / water partition coefficient, Kow, of less than 1, measured at a temperature of 25°C and a pH between 6 and 8.

[0016] As used herein, the term "hydrophobic monomer" refers to a monomer that has an octanol / water partition coefficient, Kow, greater than 1, measured at a temperature of 25°C and a pH between 6-8.

[0017] The partition coefficient, Kow, is defined as:

[0018]

number

[0019] [monomer]octanol = solubility equilibrium concentration of the monomer in n-octanol in g / L, [monomer]water = equilibrium monomer concentration in water in g / L.

[0020] According to the present invention, the weight average molecular weight of the synthetic polymer according to the present invention is determined by measuring the intrinsic viscosity. The intrinsic viscosity can be measured by methods known to those skilled in the art, and in particular can be calculated from the reduced viscosity values ​​at various concentrations by a graphical method consisting in plotting the reduced viscosity values ​​(y-axis) as a function of concentration (x-axis) and extrapolating the curve to zero concentration. The intrinsic viscosity values ​​are read on the y-axis or using the least squares method. The weight average molecular weight can then be determined by the well-known Mark-Houwink equation: [η]=KM α

[0021] [η] represents the intrinsic viscosity of the polymer as measured by solution viscometry, K represents an empirical constant, M represents the molecular weight of the polymer, α represents the Mark-Houwink coefficient, and α and K vary depending on the particular polymer-solvent system. Tables known to those skilled in the art provide values ​​of α and K depending on the polymer-solvent system.

[0022] According to the present invention, the above-mentioned monomers containing at least one unsaturated ethylenic functional group can be polymerized with each other to form a polymer. The term "polymer" refers to a product formed by the polymerization of two or more monomers. A polymer made from a single monomer type is called a homopolymer. A polymer composed of two or more different monomer types is called a copolymer.

[0023] As used herein, the term "water-soluble polymer" refers to a polymer that is dissolved in deionized water at a concentration of 2 g.L. -1 refers to a polymer that, when dissolved with stirring at 25°C for 4 hours, gives an aqueous solution free of insoluble particles.

[0024] "Anionic polymer" means a polymer containing anionic monomers and optionally nonionic monomers. "Nonionic polymer" means a polymer containing only nonionic monomers.

[0025] Amphoteric polymers are polymers that contain cationic and anionic charges (preferentially an equal number of anionic charges as cationic charges) and may also contain non-ionic monomers.

[0026] The term "particle size" refers to the average size by number of particles of the water-soluble polymer. This corresponds preferentially to the largest dimension, such as the diameter, of a spherical particle, measured with a laser measuring device using conventional techniques that form part of the knowledge of the person skilled in the art. For this purpose, devices of the Mastersizer type from Malvern, such as the MS2000 device, can be used. This type of device makes it possible to measure the particle size distribution of particles in a liquid medium or in a solid by laser diffraction.

[0027] The term "monomer unit" refers to the chemical unit associated with the corresponding monomer when polymerized in the polymer chain of a polymer.

[0028] The term "protein unit" refers to a chemical unit associated with the corresponding protein when grafted onto the polymer chain of a polymer.

[0029] The present invention therefore relates to a hybrid polymer (HP) in particle form obtained by a free radical precipitation polymerization process, which comprises the following successive steps: (A) - 50% to 95% by weight of at least one polar solvent, - 4% to 40% by weight of at least one monomer containing at least one unsaturated ethylenically functional group, and - 0.1% to 40% by weight of at least one protein preparing a solution (S1) comprising: (B) initiating polymerization in solution (S1) to obtain a dispersion (D1) comprising at least one hybrid polymer (HP), said polymer (HP) precipitating in the polymerization solvent; (C) separating the hybrid polymer (HP) in particulate form from the dispersion (D1); on hybrid polymers (HP).

[0030] The solution (S1) is preferentially produced by first mixing a monomer having at least one unsaturated ethylenically functional group with at least one polar solvent, and then subsequently adding the protein to this mixture.

[0031] The monomer containing at least one unsaturated ethylenically functional group in step (A) is preferentially a hydrophilic monomer.

[0032] The hydrophilic monomers are preferentially non-ionic and / or anionic, if non-ionic, chosen from acrylamide, methacrylamide, N,N-dimethylacrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyridine, N-vinylpyrrolidone, acryloylmorpholine (ACMO), diacetone acrylamide, or mixtures of these monomers, and if anionic, chosen from the group comprising monomers having a carboxylic acid functional group and their salts, monomers having a sulfonic acid functional group and their salts, or monomers having a phosphonic acid functional group and their salts, or mixtures of these monomers.

[0033] The solution (S1) preferentially comprises between 10% and 30% by weight of at least one hydrophilic monomer, the percentages being indicated relative to the total weight of the solution (S1).

[0034] In step (A), solution (S1) is preferably prepared from a mixture of a polar solvent and at least one monomer containing at least one unsaturated ethylenic functional group, the mixture of polar solvents containing 0.5% to 10% by weight of water and at least 90% by weight of an alcohol containing 1 to 4 carbon atoms. The alcohol containing 1 to 4 carbon atoms is preferably tert-butanol. The mixture of polar solvents preferably contains 1% to 5% by weight of water and 95% to 99% by weight of tert-butanol.

[0035] The proteins are preferentially chosen from proteins of animal origin, of plant origin and / or mixtures thereof, and are preferentially casein, serum protein, wheat protein or mixtures thereof.

[0036] A hybrid polymer (HP) preferentially comprises monomer units of at least one monomer containing at least one unsaturated ethylenic functional group and protein units, said monomer units and said protein units being partly or wholly linked by at least one covalent bond.

[0037] The hybrid polymer (HP) preferentially has a weight average molecular weight between 200,000 and 2,000,000 Daltons.

[0038] The present invention also relates to the use of the hybrid polymer (HP) according to the invention as a thickener in hydrocarbon recovery, well drilling and cementing, hydrocarbon well stimulation, papermaking, construction, mining, cosmetic formulations, detergent formulations or in the manufacture of fibers.

[0039] The present invention also relates to a thickener comprising at least one hybrid polymer (HP) according to the present invention in hydrocarbon recovery, well drilling and cementing, hydrocarbon well stimulation, papermaking, construction, mining, cosmetic formulations, detergent formulations or in the manufacture of fibers.

[0040] The present invention also relates to aqueous compositions thickened with the hybrid polymers (HP) according to the invention.

[0041] Monomers containing at least one unsaturated ethylenically functional group The hybrid polymer (HP) according to the present invention is obtained by precipitation polymerization of a monomer containing at least one unsaturated ethylenic functional group in the presence of at least one protein.

[0042] Preferentially, solution (S1) comprises between 4% and 40% by weight, and more preferentially between 10% and 30% by weight, of monomers comprising at least one unsaturated ethylenic function, the mass percentages being indicated relative to the total mass percentage of solution (S1).

[0043] The monomers may be synthetic and / or bio-based in nature.

[0044] Advantageously, these monomers are preferentially hydrophilic monomers. Hydrophilic monomers can be nonionic, anionic, cationic, or zwitterionic. Preferably, these monomers have a single ethylenic unsaturation (a double bond between two carbon atoms).

[0045] Advantageously, nonionic monomers that can be used in the context of the present invention are, in particular, acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N,N-dialkylacrylamide (for example N,N-dimethylacrylamide or N,N-diethylacrylamide), N,N-dialkylmethacrylamide, alkoxylated esters of acrylic acid, alkoxylated esters of methacrylic acid, N-vinylpyrrolidone, N-methylol(meth)acrylamide, N-vinylcaprolactam, N-vinylformamide (NVF), N-vinylacetamide, N-vinylimidazole, N-vinylsuccinimide, acryloyl The nonionic monomer is selected from the group consisting of water-soluble vinyl monomers such as morpholine (ACMO), glycidyl methacrylate, glyceryl methacrylate, diacetone acrylamide, methacrylic anhydride, acrylonitrile, maleic anhydride, itaconic anhydride, itaconamide, hydroxyalkyl (meth)acrylate, thioalkyl (meth)acrylate, isoprenol and its alkoxylated derivatives, hydroxyethyl (meth)acrylate and its alkoxylated derivatives, hydroxyethyl (meth)acrylate and its alkoxylated derivatives, hydroxypropyl acrylate and its alkoxylated derivatives, vinyl acetate, and mixtures thereof. Among these nonionic monomers, the alkyl group is preferably a C1-C5, more preferably a C1-C3 alkyl group. They are preferentially linear alkyl groups. Preferentially, the nonionic monomer is acrylamide.

[0046] Solution (S1) advantageously comprises between 1 and 99 mol % of nonionic monomers, preferentially between 2 and 70 mol %, the molar percentages being expressed relative to the total number of moles of monomers in solution (S1).

[0047] Advantageously, anionic monomers can be selected from a large group that can have vinyl, acrylic, maleic, fumaric, malonic, itaconic, or allylic functionality, including carboxylate, phosphonate, phosphate, sulfate, or sulfonate groups, or other anionic charged groups. Examples of suitable monomers include acrylic acid, methacrylic acid, dimethylacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, acrylamidoundecanoic acid, 3-acrylamido-3-methylbutanoic acid, maleic anhydride, strong acid type monomers having functional groups of sulfonic or phosphonic acid type, such as vinyl sulfonic acid, vinylphosphonic acid, allyl sulfonic acid, methallyl sulfonic acid, 2-methylidenepropane-1,3-disulfonic acid, 2-sulfoethyl methacrylate, sulfopropyl methacrylate, sulfopropyl acrylate, allyl phosphonic acid, styrene sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (ATBS), 2-acrylamido-2-methylpropanedisulfonic acid; water-soluble salts of these monomers, such as their alkali metal salts (different from the crystalline form of the sodium salt of 2-acrylamido-2-methylpropanesulfonic acid), alkaline earth metal salts, or ammonium salts; and mixtures thereof. Preferentially, the anionic monomer is acrylic acid and / or its salts.

[0048] Solution (S1) advantageously comprises between 1 and 99 mol % of anionic monomers, preferentially between 2 and 70 mol %, and even more preferentially between 3 and 50 mol % of anionic monomers, the molar percentages being expressed relative to the total number of moles of monomers in solution (S1).

[0049] According to one aspect of the present invention, the carboxylic acid functional group of the anionic monomer is salified with a salifying agent, also called a neutralizing agent. The term "salting" is understood to mean that at least one acid functional group of the anionic monomer is replaced with a salt that neutralizes the negative charge of the acid functional group. In other words, the unsalted form corresponds to the acid form of the monomer, for example, RC(=O)-OH in the case of a carboxylic acid functional group, while the neutralized form of the monomer corresponds to the form RC(=O)O-X+, where X+ corresponds to a positively charged ion. The neutralization of the acid functional group can be partial or complete.

[0050] Usually, the salification is carried out before the polymerization.

[0051] In one particular embodiment of the invention, between 30 and 100 mol % of the acid functions are salified, more advantageously between 60 and 100 mol %.

[0052] The chlorinating agent is advantageously a Brønsted base, preferably selected from ammonia, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, and mixtures thereof, with ammonia being most particularly preferred.

[0053] Advantageously, cationic monomers that can be used in the context of the present invention are selected from monomers derived from vinyl-type, especially acrylamide, acrylic, allylic, or maleic units, which have phosphonium or quaternary ammonium functional groups. In particular, but not limited to, aminoalkyl (meth)acrylates, quaternized dimethylaminoethyl acrylate (DMAEA), quaternized dimethylaminoethyl methacrylate (DMAEMA), dimethyldiallylammonium chloride (DADMAC), acrylamidopropyltrimethylammonium chloride (APTAC), and methacrylamidopropyltrimethylammonium chloride (MAPTAC). The quaternizing agent can be selected from alkyl chlorides, dialkyl sulfates, or alkyl halides. Preferentially, the quaternizing agent can be selected from methyl chloride and diethyl sulfate.

[0054] Solution (S1) advantageously comprises between 5 and 35 mol % of cationic monomer, the molar percentage being expressed relative to the total number of moles of monomer in solution (S1).

[0055] Those skilled in the art will know how to prepare quaternized monomers, for example, using alkyl halides of the type R*-X, where R* is an alkyl group and X is a halogen (especially methyl chloride). Furthermore, the present invention also covers DADMAC, APTAC, and MAPTAC type monomers in which the halide counterion is fluoride, bromide, or iodide rather than chloride.

[0056] Advantageously, the zwitterionic monomers may be derivatives of vinyl type, in particular acrylamide, acrylic, allylic or maleic acid units, which have an amine or quaternary ammonium function and an acid function of carboxyl (or carboxylate), sulfonic acid (or sulfonate) or phosphoric acid (or phosphate) type. In particular, but not exclusively, derivatives of dimethylaminoethyl acrylate, such as 2-((2-(acryloyloxy)ethyl)dimethylammonio)ethane-1-sulfonate, 3-((2-(acryloyloxy)ethyl)dimethylammonio)propane-1-sulfonate, 4-((2-(acryloyloxy)ethyl)dimethylammonio)butane-1-sulfonate, [2-(acryloyloxy)ethyl](dimethylammonio)a acetate, derivatives of dimethylaminoethyl methacrylate, such as 2-((2-(methacryloyloxy)ethyl)dimethylammonio)ethane-1-sulfonate, 3-((2-(methacryloyloxy)ethyl)dimethylammonio)propane-1-sulfonate, 4-((2-(methacryloyloxy)ethyl)dimethylammonio)butane-1-sulfonate, [2-(methacryloyloxy)ethyl](dimethylammonio)acetate acrylate, derivatives of dimethylaminopropyl acrylamide such as 2-((3-acrylamidopropyl)dimethylammonio)ethane-1-sulfonate, 3-((3-acrylamidopropyl)dimethylammonio)propane-1-sulfonate, 4-((3-acrylamidopropyl)dimethylammonio)butane-1-sulfonate, [3-(acryloyloxy)propyl](dimethylammonio)acetate, derivatives of dimethylaminopropylmethyl acrylamide such as 2-((3-methacrylamidopropyl)dimethylammonio)ethane-1-sulfonate, 3-((3-methacrylamidopropyl)dimethylammonio)propane-1-sulfonate, 4-((3-methacrylamidopropyl)dimethylammonio)butane-1-sulfonate and [3-(methacryloyloxy)propyl](dimethylammonio)acetate, and mixtures thereof.

[0057] Preferred hydrophilic monomers are acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid (ATBS) or mixtures thereof, N-vinylpyrrolidone (NVP), MADC, ADC and acrylamide.

[0058] According to one aspect of the present invention, the monomer having an ethylenic functional group is selected from the hydrophilic monomers mentioned above, and can also be selected from hydrophobic monomers.

[0059] The hydrophobic monomer having a partition coefficient Kow greater than 1 is preferably selected from the following list: Esters of (meth)acrylic acid having alkyl, arylalkyl, and / or ethoxylated and / or propoxylated chains; derivatives of (meth)acrylamide having alkyl, arylalkyl, or dialkyl and / or ethoxylated and / or propoxylated chains; cationic allyl derivatives having alkyl, arylalkyl, or dialkyl chains and / or ethoxylated and / or propoxylated chains; hydrophobic anionic or cationic (meth)acryloyl derivatives; and anionic or cationic monomeric derivatives of (meth)acrylamide having hydrophobic chains. The alkyl groups of these hydrophobic monomers are preferably C6-C24 alkyl groups. The most preferred monomers are bromoalkylated derivatives of methacrylamide dimethylaminopropyl having C8-C16 alkyl chains and ethoxylated behenyl methacrylate. n-hexyl (meth)acrylate, n-octyl (meth)acrylate, octyl (meth)acrylamide, lauryl (meth)acrylate, lauryl (meth)acrylamide, myristyl (meth)acrylate, myristyl (meth)acrylamide, pentadecyl (meth)acrylate, pentadecyl (meth)acrylamide, cetyl (meth)acrylate, cetyl (meth)acrylamide, oleyl (meth)acrylate, oleyl (meth)acrylamide, erucyl (meth)acrylate, erucyl (meth)acrylamide, and combinations thereof. - LCST (Lower Critical Solution Temperature) and / or UCST (Upper Critical Solution Temperature) monomers or macromonomers. In other words, the hydrophobicity can be attributed to the LCST and / or properties of the monomers or macromonomers. WO2020 / 094960A1 mentions such macromonomers with LCST properties. Other zwitterionic monomers are described by the applicant in document WO2021 / 123599.

[0060] In these hydrophobic monomers, - the alkyl group is preferably a C3-C20, more preferentially a C3-C8 alkyl group; a C6-C20 alkyl is preferably a linear alkyl, while a C3-C5 alkyl is preferably a branched alkyl; - the arylalkyl group is preferably a C7 to C25, more preferably a C7 to C15, arylalkyl group; the ethoxylated chain preferably contains between 6 and 100 -CH2-CH2-O- groups, and more preferentially between 10 and 40; The propoxylated chain preferably contains 1 to 50 -CH2-CH2-CH2-O- groups, more preferably 1 to 20.

[0061] Preferred hydrophobic monomers are selected from N-isopropylacrylamide; N,N-dimethylacrylamide; N,N-diethylacrylamide; N-tert-butylacrylamide; N-vinylcaprolactam; and diacetoneacrylamide.

[0062] According to this aspect of the invention, the concentration of the hydrophobic monomer is preferably between 0.0001 and 10 mol %, more preferentially between 0.001 and 5 mol %, even more preferentially between 0.01 and 3 mol %, even more preferentially between 0.1 and 2 mol %, even more preferentially between 0.2 and 1.5 mol %, even more preferentially between 0.3 and 1.3 mol %, the molar percentages being expressed relative to the total number of moles of monomer in solution (S1).

[0063] If hydrophobic monomers are added during the precipitation polymerization, the hydrophilic monomers are preferentially selected from anionic and / or nonionic hydrophilic monomers.

[0064] During the preparation of the water-soluble polymer according to the invention, the amount of the various monomers is adjusted by the person skilled in the art so as not to exceed 100 mol %.

[0065] protein The hybrid polymer (HP) according to the present invention is obtained from at least one protein, and may also be obtained from multiple proteins with different properties.

[0066] The protein is added to the polymerization ingredients in solution (S1) in step (A) of the method described in the present application.

[0067] The protein is obtained by conventional methods known to those skilled in the art, such as dissolving, grinding, sieving, classification, etc. The protein can be added to the solution (S1) in solid or liquid form. Advantageously, the protein is added in powder form.

[0068] According to the invention, the solution (S1) comprises between 0.1% and 40% by weight of protein, preferentially between 1% and 20% by weight, more preferentially between 2% and 15% by weight, and even more preferentially between 5% and 10% by weight.

[0069] Here, the term "protein" is used to include both native (or chemically unmodified) proteins and modified proteins. The term "modified protein" refers to a protein that has undergone one or more pretreatments. These pretreatments can be physical in nature, by shearing, chemical in nature, by acid or alkaline hydrolysis, and / or enzymatic in nature, via proteases.

[0070] Advantageously, natural proteins are preferred.

[0071] The proteins according to the present invention may be of animal origin, and examples of animal proteins include milk proteins such as β-lactoglobulin, casein, whey, etc.; serum proteins such as horse serum; placental proteins; and fibrous dermal proteins such as collagen, elastin, and silk proteins.

[0072] The protein according to the invention may be derived from plants such as corn, wheat, barley, oats, soybeans, peas, etc., and includes, for example, glutelin, prolamin, zein, gluten, etc. Advantageously, the vegetable protein is selected from soybean protein, wheat protein, oat protein, pea protein, etc. Proteins can be obtained from seeds such as soybeans, cottonseed, peanuts, sunflowers, rapeseed, coconuts, flaxseed, sesame, safflower, peas, beans, lentils, etc.

[0073] Other protein sources include bacteria, fungi, algae, and yeast, such as Pseudomonas, Lactobacillus, Penicillium, E. coli, blue-green algae, green algae, chlorella, spirulina, and spent yeast.

[0074] Preferentially, the protein selected is casein, a serum protein, or a wheat protein.

[0075] Conversion of proteins into soluble forms often requires digestion by physical, chemical, or enzymatic treatment, e.g., acid or alkaline hydrolysis, yeast, bacterial, or enzymatic fermentation, extraction methods to remove trace components, coagulation of extracts by heating, addition of electrolytes, pH adjustment, addition of precipitants, etc. Pure products can be prepared, e.g., by fractional dissolution and precipitation, or by dialysis.

[0076] The proteins used in the present invention can be water-soluble or water-insoluble. This does not affect the thickening efficiency of the final hybrid polymer (HP). However, the choice of protein solubility is very important in terms of application. If the goal is to obtain a viscous gel, especially for cosmetic applications, a translucent gel is preferred, in which case soluble proteins are preferred. If the transparency of the applied gel is not an issue, insoluble proteins can be selected.

[0077] Proteins can be present in the form of a mixture, which means a mixture containing several proteins from the same or different kingdoms of life, for example a mixture containing several proteins of animal origin, or a mixture containing at least one protein of animal origin and at least one protein of plant origin and / or one protein of bacterial origin.

[0078] Preferentially, a single protein is added to the polymerization ingredients in step (A).

[0079] polymerization Precipitation polymerization in a solvent consists of the polymerization of monomers that dissolve in a solvent, and the resulting polymer, which is insoluble in the solvent, precipitates in the solvent. When polymerization is complete, the polymer appears in the reaction medium in the form of a precipitate. Hybrid polymers (HP) precipitate in the polymerization solvent. Precipitation of hybrid polymers (HP) occurs during the polymerization process; it does not occur after the polymerization process. More precisely, precipitation of hybrid polymers (HP) occurs when the hybrid polymers (HP) reach a certain degree of polymerization. At the beginning of polymerization, the hybrid polymers (HP) dissolve in the reaction solvent, and the degree of polymerization, like the length of the polymer chain, increases. During the polymerization process, once a certain degree of polymerization is exceeded, the hybrid polymers (HP) become insoluble in the polymerization solvent, and the hybrid polymers (HP) precipitate. The polymerization continues until the end.

[0080] The hybrid polymer (HP) is produced by polymerization between at least one monomer containing at least one unsaturated ethylenic functional group and at least one protein. According to the present invention, the hybrid polymer (HP) is polymerized by free radical precipitation polymerization in a polar solvent.

[0081] In step (A) of the method, a solution (S1) is prepared by including 4% to 40% by weight of a monomer having at least one unsaturated ethylenically functional group, 60% to 95% by weight of at least one polar solvent, and 0.1% to 40% by weight of at least one protein, as described above, the percentages being given relative to the total weight of (S1) and adding up to 100%.

[0082] According to a preferred embodiment, the solution (S1) is produced by first mixing a monomer having an unsaturated ethylenically functional group with at least one polar solvent, and then subsequently adding the protein to this mixture.

[0083] According to the invention, a polar solvent or a mixture of polar solvents can be used, which mixture of polar solvents comprises preferentially water and an alcohol or a ketone.

[0084] The alcohol or ketone is preferentially selected from methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-2-propanol, 1-butanol, 2-butanol, dimethyl ketone, diethyl ketone, pentan-2-one, butanone, tetrahydropyran, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxane, 1,4-dioxane. The mixture of polar solvents is preferably a mixture of protic solvents (proton donors).

[0085] In one particular embodiment of the invention, the solvent used for the precipitation polymerization is preferentially an alcohol containing 1 to 4 carbon atoms, advantageously selected from methanol, ethanol, propan-1-ol, isopropanol, tert-butanol or mixtures thereof, and preferentially the solvent used is tert-butanol alone.

[0086] The mixture of polar solvents preferentially comprises up to 10% by weight of water, preferentially between 1% and 6% by weight of water, and even more preferentially between 2% and 4% by weight of water.

[0087] The mixture of polar solvents preferentially comprises at least 90% by weight of alcohol, more preferentially at least 95% by weight of alcohol, and even more preferentially at least 97% by weight of alcohol.

[0088] Thus, preferentially, the mixture of polar solvents used for the precipitation polymerization comprises less than 10% by weight of water and at least 90% by weight of tert-butanol, preferentially from 1% to 5% by weight of water and from 99% to 95% by weight of tert-butanol, and even more preferentially from 2.5% by weight of water and 97.5% by weight of tert-butanol.

[0089] According to the invention, the polymerization is preferentially carried out in the absence of oxygen. Degassing consists in removing residual oxygen from the solution (S1) obtained at the end of step (A). To do this, an inert gas is introduced to degas the solution (S1), which is usually passed through the solution. Suitable inert gases for this purpose are, for example, nitrogen or carbon dioxide.

[0090] According to one embodiment of the present invention, a surfactant is added to stabilize the medium in order to obtain optimal polymerization conditions. Solution (S1) can contain at least one surfactant with an HLB (hydrophilic-lipophilic balance) of less than 15, preferentially between 9 and 13, in order to stabilize said solution S1 and improve the polymerization. Generally, the amount of said surfactant in solution (S1) is between 0.2% and 20% by weight, preferentially between 1% and 10% by weight.

[0091] The hydrophilic-lipophilic balance (HLB) of a chemical compound is a measure of its hydrophilic and / or lipophilic properties, determined by calculating values ​​for various regions of the molecule, as described by Griffin in 1949.

[0092] The surfactant may be nonionic, anionic, cationic, amphoteric, or zwitterionic, and is preferably a nonionic surfactant.The surfactant is preferably selected from ethoxylated surfactants, PEG diacrylates, ethers of ethoxylated fatty alcohol type, sugar or polyhydric alcohol esters or esters prepared based on other alcohols such as betaine, glycerol, diglycerol, or triglycerol type alcohols, or sugars such as maltitol or sorbitol, and mixtures thereof.Advantageously, alkyl polyglucosides are used.

[0093] According to one aspect of the present invention, solution (S1) may contain a crosslinking agent. The crosslinking agent is advantageously selected from polyfunctionalizing agents such as methylenebisacrylamide (MBA), ethylene glycol diacrylate, polyethylene glycol dimethacrylate, diacrylamide, cyanomethyl acrylate, vinyloxyethyl acrylate, vinyloxymethacrylate, triallylamine, trimethylolpropane triacrylate (TMPTA), tetraallylammonium chloride (TAAC), formaldehyde, glyoxal, glycidyl ethers such as ethylene glycol diglycidyl ether, epoxides, and mixtures thereof. Preferentially, the crosslinking agent is trimethylolpropane triacrylate (TMPTA).

[0094] Solution (S1) preferentially comprises between 500 ppm and 5000 ppm by weight of crosslinker relative to the total weight of solution (S1), more preferentially between 1600 and 3700 ppm by weight, and even more preferentially between 2500 and 3200 ppm by weight of crosslinker.

[0095] According to the method of the present invention, polymerization is initiated using one or more of the hydrophilic and / or hydrophobic monomers and a protein using a free radical initiator. Examples of free radical initiators include redox couples such as cumene hydroperoxide or tert-butylhydroxyperoxide as an oxidizing agent and persulfates such as sodium metabisulfite or Mohr's salt as a reducing agent. Azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), and 2,2'-azobis(2-amidinopropane) hydrochloride can also be used, as can peroxide compounds such as benzoyl peroxide, tert-butyl hydroperoxide, and lauroyl peroxide.

[0096] Before starting the polymerization, the degassing is stopped and the polymerization is carried out under reflux for several hours, preferentially for at least 2 hours.

[0097] According to the invention, the free radical precipitation polymerization is carried out at atmospheric pressure and at a temperature between 60 and 85°C.

[0098] Step (B) of the process consists in initiating the polymerization of the solution (S1) to obtain a dispersion (D1) containing the hybrid polymer (HP). The polymer (HP) is in the form of a precipitate. Step (C) of the process consists in isolating the hybrid polymer (HP) in the form of particles. The hybrid polymer (HP) can be easily isolated using the usual separation, evaporation and drying processes known to those skilled in the art. The solvent can be extracted by filtration or distillation, but extraction by distillation is preferred.

[0099] The hybrid polymer (HP) is then recovered in the form of particles. Generally, the size of the particles of the hybrid polymer (HP) is advantageously between 5 nm and 5 mm, more advantageously between 50 nm and 5 mm, preferentially between 100 nm and 2 mm, and even more preferentially between 200 μm and 1 mm. Specifically, it may be between 50 nm and 1 mm, or between 500 μm and 5 mm, or between 5 μm and 1 mm, or between 100 μm and 1 mm.

[0100] Hybrid Polymer The weight average molecular weight of the hybrid polymer (HP) is advantageously between 200,000 and 2,000,000 daltons, preferentially between 300,000 and 1,500,000 daltons.

[0101] The Brookfield viscosity of the hybrid polymer (HP) is preferentially between 1,000 and 100,000 cPs, more preferentially between 2,500 and 75,000 cPs, and even more preferentially between 5,000 and 50,000 cPs. The Brookfield viscosity is measured on a 1% by weight aqueous polymer solution using a Brookfield RVT unit viscometer at a rotation speed of 20 rpm.

[0102] The hybrid polymers (HP) can be linear, structured or branched. Preferentially, the (HP) are structured, i.e., star-branched or comb-shaped.

[0103] The hybrid polymer (HP) comprises less than 40% by weight of protein, preferentially between 10% and 40% by weight of protein, and even more preferentially between 15% and 35% by weight of protein.

[0104] In the hybrid polymer (HP), the mass ratio of monomer units to protein units is preferentially between 50 / 1 and 1 / 5, preferentially between 25 / 1 and 1 / 3, more preferentially between 10 / 1 and 1 / 2, and even more preferentially between 6 / 1 and 1 / 1.

[0105] From the NMR / DOSY analysis of FIG. 1, it is possible to observe that the hybrid polymer (HP) according to the present invention has at least partially covalent bonds between the protein and the monomer containing at least one ethylenic functional group.

[0106] From this analysis it is possible to conclude that the hybrid polymer (HP) according to the invention is present in a mixture comprising at least a hybrid polymer (HP) having at least partially covalent bonds between the protein and the at least one ethylenically functionalized monomer, the at least one ethylenically functionalized monomer having reacted with each other to form the water-soluble polymer and the protein alone.

[0107] D2O and TSP-d4 are deuterated NMR solvents. They allow the product to be dissolved without generating signals, which would otherwise interfere with the reading of the NMR spectrum, since the solvent is usually present in such large excess.

[0108] Various applications of hybrid polymers The invention also relates to the use of hybrid polymers (HP) as thickeners in the recovery of hydrocarbons (oil and / or gas), in the drilling and cementing of wells, in the treatment of water in open, closed or semi-closed circuits, in the treatment of fermentation liquors, in the treatment of sludge, in papermaking, in construction, in the treatment of wood, in the treatment of hydraulic compositions (concrete, cement, mortar and aggregates), in mining, in the formulation of cosmetics, in the formulation of detergents, in the manufacture of textile printing pastes, in the manufacture of battery components, in geothermal applications, in the manufacture of sanitary layers or in agriculture.

[0109] Advantageously, the present invention relates to the use of a hybrid polymer (HP) according to the invention as a thickener, conditioner, stabilizer, emulsifier, fixer or film former in the preparation of a cosmetic composition.

[0110] The present invention also relates to the use of a hybrid polymer (HP) as a thickener for pigment compositions used in textile printing, said thickener comprising at least one hybrid polymer according to the invention.

[0111] The present invention also relates to a method for enhancing oil or gas recovery by flushing of subterranean formations, comprising the step of using at least one hybrid polymer (HP) according to the present invention.

[0112] The present invention also relates to a thickener comprising at least one hybrid polymer (HP) according to the present invention in the fields selected from the following: hydrocarbon recovery, well drilling and cementing, hydrocarbon well stimulation, papermaking, construction, mining, cosmetic formulation, detergent formulation, textile manufacturing.

[0113] The present invention also relates to aqueous compositions thickened with the hybrid polymers (HP) according to the invention.

[0114] Other Subject Matter According to the Invention The present invention also relates to a hybrid polymer (HP) comprising monomer units of at least one monomer comprising at least one unsaturated ethylenic functional group and protein units, characterized in that the monomer units and the protein units are partially or totally linked by at least one covalent bond, and the mass ratio of the monomer units to the protein units is between 50 / 1 and 1 / 5, preferentially between 25 / 1 and 1 / 3, more preferentially between 10 / 1 and 1 / 2, and even more preferentially between 6 / 1 and 1 / 1.

[0115] The present invention also provides a method for producing a method for manufacturing a pharmaceutical composition comprising the following sequential steps: (A) preparing a mixture (M1) comprising at least one monomer containing at least one unsaturated ethylenic functional group, and between 0.1% and 50% by weight of at least one protein, and optionally at least one solvent; (B) initiating polymerization in the mixture (M1) to obtain a hybrid polymer (HP); The present invention relates to a hybrid polymer (HP) obtained by free radical polymerization according to a method comprising:

[0116] The mixture (M1) preferably comprises between 5% and 90% by weight, more preferentially between 10% and 80% by weight, more preferentially between 15% and 80% by weight, more preferentially between 20% and 80% by weight, more preferentially between 25% and 80% by weight, more preferentially between 30% and 80% by weight, more preferentially between 35% and 75% by weight, more preferentially between 40% and 75% by weight, more preferentially between 45% and 75% by weight, more preferentially between 50% and 70% by weight, more preferentially between 55% and 65% by weight of at least one monomer comprising at least one unsaturated ethylenic functional group.

[0117] The mixture (M1) preferably contains between 0.1% and 50% by weight of at least one protein, more preferably between 1% and 40%, even more preferably between 3% and 35%, even more preferably between 5% and 30%, even more preferably between 10% and 25%.

[0118] The mixture (M1) preferably comprises between 1% and 90% by weight of at least one solvent, more preferably between 5% and 80%, even more preferably between 10% and 70%, even more preferably between 15% and 60%, and even more preferably between 20% and 50%.

[0119] Another subject of the present invention is the use of the hybrid polymer (HP) described above as a thickener. The present invention also relates to a viscosity modifier comprising at least said hybrid polymer (HP).

[0120] Generally, polymerization is initiated by a free radical initiator, as presented in this application, but can also be initiated by the action of UV radiation.

[0121] The polymerization is preferentially carried out in the temperature range of 20°C to 160°C, more preferably 30°C to 100°C.

[0122] The polymerization is preferably carried out in an inert gas atmosphere in the absence of atmospheric oxygen, for example using nitrogen or carbon dioxide as the inert gas.

[0123] The reaction temperature and the amount of initiator usually have a significant effect on the polymerization of hybrid polymers (HP).

[0124] Advantageously, the monomer containing at least one unsaturated ethylenic functional group and the protein to be polymerized are first introduced into a reaction vessel together with at least one polymerization initiator and polymerized by heating to an optimal polymerization temperature. It may be advantageous to use two or more proteins.

[0125] The order in which reactants are fed to the polymerization reactor can be freely changed. When multiple monomers are used in the graft copolymerization, the individual monomers can be fed to the polymerization zone from separate feed means sequentially, in the form of a mixture, or simultaneously. For example, the protein solution or dispersion in the reactor can be heated to the required polymerization temperature, and the monomers and initiator can be added continuously or in batches.

[0126] Similarly, the pH of the reaction medium can also affect the hybrid polymer (HP). Acidic or basic monomers can be used in the form of their corresponding salts. For example, acrylic acid can be used in the form of the free acid or in the form of an alkali metal salt. The polymerization can be carried out in a pH range of 1 to 14, preferably 6 to 12. By changing the pH, it is possible, for example, to precipitate the graft copolymer from the solution. This possibility can be utilized during the processing, purification, and separation of the graft copolymer.

[0127] The proteins used in the graft copolymerization can be chemically modified in a variety of ways before or after the graft polymerization.

[0128] DOSY experiments, an NMR technique, allow the separation of species present according to their diffusion coefficients in a solvent, enabling the analysis of complex mixtures to detect traces. The purpose of this experiment is to demonstrate the presence of at least one covalent bond between a protein and a monomer containing at least one ethylenic functional group. DOSY experiments consist of recording proton spectra while varying the applied gradient force (G) and the diffusion force. As the gradient strength increases linearly, the NMR signal intensity decreases exponentially. DOSY experiments produce two-dimensional maps.

[0129] The second dimension, F2, of a DOSY experiment corresponds to dimension 1H after Fourier transformation processing. The first dimension, F1, corresponds to the decrease in the NMR signal as a function of the applied gradient force. After processing dimension F2, the diffusion coefficients are extracted and the DOSY map is obtained. If the diffusion coefficients of the two matrices are the same, it means that the two matrices have the same hydrodynamic radius and are therefore grafted. On the other hand, if the two matrices have two different diffusion coefficients, it means that they do not affect each other.

[0130] 1 and 2, NMR analyses were performed on a Bruker 400 MHz ASCEND™ Avance III HD type instrument equipped with a 10 mm BBO 400 MHz ZG radiation probe. TSP-d4 is deuterated sodium trimethylsilylpropionate.

[0131] Conclusion: The diffusion coefficient of the signal associated with the protein in the hybrid polymer is different from the diffusion coefficient of the protein alone (isolated).

[0132] NMR / DOSY (Diffusion Ordering Spectroscopy) analysis of a sample of the pure product (product obtained after polymerization, without additional treatment) made it possible to show that the protein was grafted onto ATBS and that subsequently the unsaturated monomer was also grafted onto the oligomer. [Example]

[0133] The following examples make it possible to clearly illustrate the advantages of the present invention in a clear and non-limiting manner.

[0134] I- Synthesis of Hybrid Polymers According to the Invention

[0135] Example 1 HPA = ATBS homopolymer + casein 450 g of tert-butanol containing 2.5% by weight of water is introduced into a jacketed reactor equipped with a stirring blade. 2-Acrylamido-2-methylpropanesulfonic acid (ATBS) is added while stirring. Gaseous ammonia is bubbled through the medium for 30 minutes, ensuring that the pH does not exceed 7. The preparation is degassed in the reactor by injecting nitrogen for 30 minutes. During this time, the medium is gradually heated to 55 °C. Next, trimethylolpropane triacrylate (TMPTA, crosslinker / branching agent) is added, followed by casein (milk protein), and the temperature of the medium is raised to 70 °C using a thermostatic bath. The polymerization reaction is initiated by adding 0.6 g of dilauroyl peroxide. The polymerization begins rapidly and reaches a maximum exotherm. Once the maximum temperature is reached, the medium is refluxed for 2 hours.

[0136] The presence of a white precipitate in the solvent (tert-butanol + 2.5% by weight of water) is observed. This white precipitate corresponds to the hybrid copolymer of the present invention. The solvent is then removed using a rotary evaporator under oil heating at 90 ° C and a vacuum of 100 mbar. The resulting copolymer is then dried overnight at 70 ° C.

[0137] Table 1 below summarizes the compositions and viscosities of polymer HPAs.

[0138] Brookfield viscosity is measured on a 1 wt % aqueous polymer solution using a Brookfield RVT unit viscometer at a rotation speed of 20 rpm.

[0139] [Table 1]

[0140] Example 2 HPB = ATBS + acrylic acid copolymer + casein The procedure is the same as that used in the Hybrid Polymer 1 example, except that the monomers used are 2-acrylamido-2-methylpropanesulfonic acid (ATBS) and acrylic acid (30 / 70 mol%). The polymerization reaction is initiated by adding 0.4 g of 2,2'-azobis(2-methylpropionamidine) dihydrochloride. The polymerization begins rapidly and reaches a maximum exotherm. Once the maximum temperature is reached, the medium is refluxed for 2 hours.

[0141] Hybrid polymer 2 is also recovered in the same manner as above.

[0142] By adjusting the amount of protein and the amount of cross-linker, the desired viscosity and naturalness / biodegradability goals can be achieved.

[0143] Table 2 below summarizes the composition and viscosity of polymer HPB.

[0144] [Table 2]

[0145] Example 3 HP C = HP without crosslinker A 450 g of tert-butanol containing 2.5% by weight of water is introduced into a jacketed reactor equipped with a stirring blade. 2-Acrylamido-2-methylpropanesulfonic acid (ATBS) is added while stirring. Gaseous ammonia is bubbled through the medium for 30 minutes, ensuring that the pH does not exceed 7. The preparation is degassed in the reactor by injecting nitrogen for 30 minutes. During this time, the medium is gradually heated to 55°C. Micellar casein (milk protein) is then added, and the temperature of the medium is raised to 70°C using a thermostatic bath. The polymerization reaction is initiated by adding 0.6 g of dilauroyl peroxide. The polymerization begins rapidly and reaches a maximum exotherm. Once the maximum temperature is reached, the medium is refluxed for 2 hours.

[0146] The presence of a white precipitate in the solvent (tert-butanol + 2.5% by weight of water) is observed. This white precipitate corresponds to the hybrid copolymer of the present invention. The solvent is then removed using a rotary evaporator under oil heating at 90 ° C and a vacuum of 100 mbar. The resulting copolymer is then dried overnight at 70 ° C.

[0147] Table 3 below shows the polymer HP C The composition and viscosity of

[0148] [Table 3]

[0149] Example 4 Hybrid Polymer HP D ~HP O Synthesis of Hybrid Copolymer HP D HPo is prepared according to the protocol of Example 1. The polymerization is carried out at 15% by weight of active substance relative to the reaction medium. The amounts of the individual monomers are adjusted to obtain the proportions shown in Table 4 below for each example.

[0150] [Table 4]

[0151] II-Application Examples

[0152] Example 5 Textile applications: Pigment printing paste prepared in an aqueous solution. A pigment printing paste is prepared with a viscosity of 6500 cPs, measured at 25°C and 20 rpm using a Brookfield RV Unit Viscometer. The printing paste contains 12% of the binder (styrene / acrylic copolymer) Helizarin 83 LiqC (Archroma) or equivalent, and 1.5% of a dispersion of blue pigment PIGMACOLOR BLUE (KEMITEKS). The entire mixture is mixed, and then Hybrid Polymer D (Example 1) is added with stirring as a thickener to thicken the printing paste. The amount of Hybrid Polymer D and the amounts of the other ingredients are also adjusted to obtain a target viscosity of 6500 cPs.

[0153] The hybrid polymer D according to Example 1 and two comparative examples outside the present invention, a thickened acrylic inverse emulsion and a thickened acrylic polymer obtained by precipitation polymerization (PA-PPP), are shown in Table 5 below.

[0154] [Table 5]

[0155] The produced glue is evaluated in terms of application performance quality such as color yield, fixation, and penetration, which are the main control parameters in screen printing.

[0156] The printing system is a Stork FAM-R type printing table; the magnetic transfer doctor blade is a model with a diameter of 10 mm and a length of 30 cm, and the printing frame is a model with 125 mesh openings.

[0157] To characterize the various parameters, three types of fabrics are used: - 100% cotton canvas; - 100% polyester satin and - 97 / 3 cotton elastane satin.

[0158] After printing, the design is fixed by passing it through a dryer at 160°C for 3 minutes.

[0159] The results are compared to one another according to the judgment of one skilled in the art, and are recorded in Table 6 below.

[0160] [Table 6]

[0161] Precipitation polymerized acrylic polymers are known to have inferior application performance characteristics compared to benchmark inverse emulsion thickeners, which is why inverse emulsion thickeners are generally preferred in the screen printing world.

[0162] Surprisingly, it can be observed that Hybrid Polymer D obtained by precipitation polymerization according to the invention has significantly better printing performance properties than the "benchmark" acrylic (PA-PPP) obtained by the same polymerization method. Furthermore, Hybrid Polymer D consumes less water while matching the benchmark obtained by inverse emulsion, showing a clear advantage.

[0163] Example 6 Petroleum applications: The hybrid polymer HPp is prepared according to the method described in Example 1. Its composition and properties are shown in Table 7 below.

[0164] [Table 7]

[0165] Testing for drilling applications: 600g of G-grade cement, 4.5g of hybrid polymer HPp, 1.8g of retarder (CR104), 1.2g of dispersant (CD-1B) and 264g of deionized water are added to the mixer. The whole is mixed at a speed of 4000 rpm for 15 seconds, then at 12000 rpm for 35 seconds, and then placed in a consistency meter at 85°C for 20 minutes.

[0166] Next, the fluid loss is measured using a HTHP filter press at 85°C and 1000 psi for 30 minutes. For the benchmark, the fluid loss is 32 mL. For the hybrid polymer, the fluid loss is 38 mL. The latter is in good agreement with the required properties.

[0167] Example 7 Cosmetic applications: The following compositions contain hybrid polymers C or I, which are hybrid polymers obtained according to Example 1.

[0168] Table 8 below details examples of cosmetic formulations containing 1% by weight of hybrid polymers C and I.

[0169] [Table 8]

[0170] Cosmetic compositions containing the hybrid polymers according to the present invention achieve a target viscosity and meet the technical requirements of cosmetics.

Claims

1. A hybrid polymer (HP) in particle form obtained by a free radical precipitation polymerization process, the free radical precipitation polymerization process comprising the following successive steps: (A) - 50% to 95% by weight of at least one polar solvent, - 4% to 40% by weight of at least one monomer containing at least one unsaturated ethylenically functional group, and - 0.1% to 40% by weight of at least one protein preparing a solution (S1) comprising: (B) initiating polymerization in solution (S1) to obtain a dispersion (D1) comprising at least one hybrid polymer (HP), said polymer (HP) precipitating in the polymerization solvent; (C) separating the hybrid polymer (HP) in particulate form from the dispersion (D1); Hybrid polymer (HP) by.

2. 2. The hybrid polymer (HP) according to claim 1, characterized in that the solution (S1) is produced by first mixing a monomer having at least one unsaturated ethylenically functional group with at least one polar solvent, and then subsequently adding a protein to the mixture.

3. 3. Hybrid polymer (HP) according to claim 1 or 2, characterized in that the monomer containing at least one unsaturated ethylenic functional group in step (A) is a hydrophilic monomer.

4. 4. Hybrid polymer (HP) according to claim 3, characterized in that the hydrophilic monomers are nonionic and / or anionic, selected from acrylamide, methacrylamide, N,N-dimethylacrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyridine, N-vinylpyrrolidone, acryloylmorpholine (ACMO), diacetone acrylamide, or mixtures of these monomers if nonionic, or selected from the group comprising monomers having carboxylic acid functional groups and their salts, monomers having sulfonic acid functional groups and their salts, or monomers having phosphonic acid functional groups and their salts, or mixtures of these monomers if anionic.

5. Hybrid polymer (HP) according to any one of claims 1 to 4, characterized in that the solution (S1) comprises 10% to 30% by weight of at least one hydrophilic monomer, the percentages being expressed relative to the total weight of the solution (S1).

6. 6. Hybrid polymer (HP) according to any one of claims 1 to 5, characterized in that in step (A), solution (S1) is prepared from a mixture of a polar solvent and at least one monomer comprising at least one unsaturated ethylenic functional group, said mixture of polar solvents comprising 0.5% to 10% by weight of water and at least 90% by weight of an alcohol comprising 1 to 4 carbon atoms.

7. 7. The hybrid polymer (HP) according to claim 6, characterized in that the alcohol containing 1 to 4 carbons is tert-butanol.

8. 8. Hybrid polymer (HP) according to claim 6 or 7, characterized in that the mixture of polar solvents comprises 1% to 5% by weight of water and 95% to 99% by weight of tert-butanol.

9. Hybrid polymer (HP) according to any one of claims 1 to 8, characterized in that the proteins are chosen from proteins of animal origin, plant origin and / or mixtures thereof.

10. 10. Hybrid polymer (HP) according to any one of claims 1 to 9, characterized in that the protein is casein, serum protein, wheat protein or a mixture thereof.

11. 11. A hybrid polymer (HP) according to any one of claims 1 to 10, characterized in that it comprises monomer units of at least one monomer comprising at least one unsaturated ethylenic functional group and protein units, said monomer units and said protein units being partly or wholly linked by at least one covalent bond.

12. Hybrid polymer (HP) according to any one of claims 1 to 11, characterized in that the hybrid polymer (HP) has a weight average molecular weight between 200,000 and 2,000,000 Daltons.

13. 13. Use of a hybrid polymer (HP) according to any one of claims 1 to 12 as a thickener in hydrocarbon recovery, well drilling and cementing, hydrocarbon well stimulation, papermaking, construction, mining, cosmetic formulations, detergent formulations or textile manufacturing.

14. 13. A thickener comprising at least one hybrid polymer (HP) according to any one of claims 1 to 12, for use in hydrocarbon recovery, well drilling and cementing, hydrocarbon well stimulation, papermaking, construction, mining, cosmetic formulations, detergent formulations, or fiber manufacturing.

15. 13. An aqueous composition thickened with a hybrid polymer (HP) according to any one of claims 1 to 12.

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