Preparation of a hydrophobic polyether compound

Abstract

The invention relates to a thickening copolymer and a non-continuous method for preparing the same. The preparation method first involves a polymerization reaction between a dihalogenated compound and a polyhydroxylated monomer, followed by a reaction with a hydrophobic monoalcohol. Said copolymer makes it possible to control the viscosity of an aqueous composition.

Description

[0001] PREPARATION OF HYDROPHOBIC POLYETHER COMPOUND

[0002] The invention relates to a thickening copolymer and its batch preparation method. The preparation method first comprises a polymerization reaction of a dihalogenated compound and a polyhydroxylated monomer and then the reaction with a hydrophobic monoalcohol. This copolymer makes it possible to control the viscosity of an aqueous composition.

[0003] Many technical fields require controlling the rheology of the compositions used, in particular controlling the rheology of aqueous compositions. Having a variety of effective thickening agents is therefore very useful.

[0004] Among the thickening agents, we distinguish associative thickeners which are generally water-soluble polymers comprising hydrophobic groups that are often insoluble in water. Such macromolecules have an associating character: once introduced into water, the hydrophobic groups are likely to assemble in the form of micellar aggregates. These aggregates are linked together by the hydrophilic parts of the polymers. This results in the formation of a three-dimensional network which causes an increase in the viscosity of the medium.

[0005] Within compositions also comprising a latex-type binder compound, thickening agents generally allow interactions to develop with the particles of these binder compounds. Such interactions then generally allow the thickening effect to be increased. Generally, methods for preparing thickening compositions, comprising a hydrophilic polymer, advantageously water-soluble, which are flexible and reproducible, are sought. It is also sought to improve the thickening efficiency of the thickening agent obtained. According to the invention, the term "water-soluble polymer" means a polymer that is completely miscible with water at a temperature above the melting temperature of this polymer.

[0006] Generally speaking, for aqueous coating compositions, and in particular for aqueous paint or varnish compositions, it is necessary to control the viscosity for both low or medium shear rates and high shear rates. Indeed, during its preparation, storage, application or drying, a paint formulation is subject to numerous constraints requiring particularly complex rheological properties.

[0007] During paint storage, pigment particles tend to settle by gravity. Stabilizing the dispersion of these pigment particles then requires a paint formulation with high viscosity at very low shear rates corresponding to the limiting velocity of the particles.

[0008] Paint pick-up is the amount of paint carried away by an application tool, such as a paintbrush, brush, or roller. A tool that is dipped and then removed from the paint pot carries a high amount of paint, thus avoiding the need for more frequent refilling. Paint pick-up is an increasing function of viscosity. The equivalent shear rate calculation is a function of the paint flow rate for a particular thickness of paint on the tool. The paint formulation should therefore also have a high viscosity at low or medium shear rates.

[0009] In addition, a high filling power of the paint must be sought so that when it is applied to a substrate, a significant quantity of paint is deposited during each pass. A high filling power then makes it possible to obtain a larger wet film during each pass of the tool. A high viscosity of the paint formulation must therefore be sought at high shear rates.

[0010] High viscosity at high shear rates will also reduce or eliminate the risk of splatter or droplet formation during paint application.

[0011] WO 9631550 describes a method for preparing polymers from dihalides and α,β-difunctional polyethers and finally from halogenated compounds. The article by Lebreton et al. (A facile synthesis of hydrophobically end-capped poly(oxymethylene-co-polyethyleneoxide) by controlled step condensation, Designed monomers and polymers, 1999, vol. 2) describes triblock polymers prepared discontinuously by condensation of polyethylene glycol, dichloromethane and a polyethoxylated fatty alcohol. Hydrophobic compounds, including hydrophobically modified compounds such as associative nonionic thickening agents, are known as rheology modifying agents. However, known compounds do not always provide a satisfactory solution. There is therefore a need for improved rheology modifying agents.

[0012] Furthermore, it is also important to have improved copolymer preparation methods. Indeed, known methods can generate many problems making them difficult to implement. It may prove impossible to effectively implement certain thickening agent preparation methods because the problems encountered can be difficult to overcome, in particular the problems of viscosity drift of the reaction medium for preparing thickening agents.

[0013] It is also important to have flexible preparation methods, including methods that allow the reactants introduced (nature, quantity) into the reaction zones to be varied during synthesis. Improving the reproducibility of copolymer preparation methods must also be sought.

[0014] There is therefore a need for a method of preparing a thickening copolymer which can provide a solution to all or part of the problems of the known methods.

[0015] Thus, the invention provides a method for the discontinuous preparation of a copolymer P comprising:

[0016] * the polymerization reaction in the presence of a base: a) of at least one dihalogenated compound a of formula I:

[0017] LX^ (I) in which:

[0018] - L independently represents a divalent hydrocarbon group;

[0019] - X 1 independently represents Br or I; b) at least one polyhydroxylated monomer b used in a molar quantity providing a number of hydroxyl groups (OH) lower than the number of halides provided by compound a and

[0020] * the reaction with at least one hydrophobic monoalcohol c. For the effectiveness of the method according to the invention, the presence of a base is essential to allow the reaction of the polyhydroxylated monomer b and the monoalcohol c with the dihalogenated compound a. Preferably according to the invention, the base is used in a molar excess relative to the molar quantity of OH groups of the monomer b and the monoalcohol c. More preferably, the base is used in a molar quantity of 1.05 to 15, preferably 2 to 13, molar equivalents relative to the molar quantity of OH groups of the monomer b and the monoalcohol c.

[0021] The base used leads to an increase in pH when implementing the method according to the invention. Preferably, the polymerization is carried out at a pH greater than 10 or greater than 12.

[0022] According to the invention, many bases can be used. Preferably according to the invention, the base is a strong mineral base or a strong organic base. More preferably, the base is chosen from sodium hydride, potassium hydride, NaOH, KOH, sodium methanolate, potassium methanolate, sodium ethanolate, potassium ethanolate, sodium tert-butanolate, potassium tert-butanolate. Sodium hydroxide is the preferred base.

[0023] Generally according to the invention the base makes it possible to obtain the alcoholate derivative of compound b or the alcoholate derivative of monoalcohol c. Advantageously, the treatment, total or partial by means of the base, of compound b or of monoalcohol c, prior to carrying out the reaction, can make it possible to directly introduce this alcoholate derivative of compound b or this alcoholate derivative of monoalcohol c. The alcoholate derivative of compound b or the alcoholate derivative of monoalcohol c can optionally be stored separately and then introduced during the carrying out of the reaction in the presence of compound a.

[0024] The method according to the invention comprises the polymerization of the polyhydroxylated monomer b and the dihalogenated compound a. Preferably, the method according to the invention uses a single dihalogenated compound a or 2 or 3 different dihalogenated compounds a. Preferably according to the invention, the dihalogenated compound a is a compound of formula I in which:

[0025] - L independently represents a Ci-Cio-alkylene group, more preferably a Ci-C2-alkylene group, much more preferably CH2;

[0026] - X 1 independently represents Br or I, preferably Br.

[0027] Also preferably, the method according to the invention uses a single polyhydroxylated compound b or 2 or 3 different polyhydroxylated compounds b. More preferably according to the invention, the polyhydroxylated compound b is a compound comprising 2, 3 or 4 hydroxyl groups.

[0028] More preferably, the polyhydroxylated compound b is a compound bl of formula II: HO-Q11-OH (II) in which:

[0029] - Q independently represents an oxyalkylene group, preferably chosen from oxyethylene, oxyethylene-oxypropylene comprising at most 40 mol% of oxypropylene, oxyethylene-oxybutylene comprising at most 20 mol% of oxybutylene, and combinations thereof,

[0030] - n independently represents a number ranging from 20 to 800.

[0031] In order for the oxyethylene-oxypropylene copolymer to retain its water-soluble character, its oxypropylene content is less than 40 mol%, advantageously less than 35 mol%. In order for the oxyethylene-oxybutylene copolymer to retain its water-soluble character, its oxybutylene content is less than 20 mol%, advantageously less than 15 mol%.

[0032] The preferred polyhydroxylated compound b1 of formula II comprises oxyethylene Q groups. Preferably according to the invention, the polyhydroxylated compound b has a molar mass (Mw) ranging from 800 to 40,000 g / mol, preferably from 2,000 to 20,000 g / mol, more preferably from 2,000 to 15,000 g / mol. According to the invention, the molar mass of compound b is determined by Size Exclusion Chromatography (SEC). Also preferably, the method according to the invention uses a single hydrophobic monoalcohol c or 2 or 3 different hydrophobic monoalcohols c.

[0033] More preferably, the hydrophobic monoalcohol is a compound of formula III: R- X n -OH (III) in which: - R independently represents a hydrophobic hydrocarbon group, preferably a linear, branched or cyclic, saturated, unsaturated or aromatic hydrocarbon group, or comprising from 6 to 40 carbon atoms,

[0034] - n represents 0 or a number ranging from 1 to 500,

[0035] - X independently represents an alkoxylated group, preferably an alkoxylated group chosen from an ethoxylated group, a propoxylated group, a butoxylated group and combinations thereof.

[0036] According to the invention, the hydrocarbon group R advantageously represents a linear, branched or cyclic alkyl or alkenyl group, advantageously linear or branched, comprising from 6 to 40 carbon atoms, preferably from 6 to 32 carbon atoms.

[0037] According to the invention, the hydrocarbon group R may also comprise an aromatic group comprising from 6 to 40 carbon atoms, preferably from 7 to 32 carbon atoms.

[0038] According to the invention, the hydrocarbon group R may comprise a radical of formula IV: in which R” represents a hydrocarbon group of formula C15H31-X in which x = 0, 2, 4, 6; thus being able to comprise 0, 1, 2 or 3 ethylenic unsaturations (double bond). Such a radical of formula (IV) is advantageously derived from cardanol, and thus of bio-sourced and non-polluting origin.

[0039] According to the invention, the hydrocarbon group R may also comprise a tristyrylphenyl (TSP) group of formula: or a distyrylphenyl (DSP) group of formula:

[0040] Preferably according to the invention, n can represent 0. The compound is then a non-alkoxylated monoalcohol. Also preferably according to the invention, n can represent a number ranging from 2 to 100, preferably a number ranging from 2 to 50 or from 5 to 25.

[0041] Preferably according to the invention, X represents an ethoxylated group or a propoxylated group or a combination of ethoxylated groups and propoxylated groups.

[0042] Preferably according to the invention, n represents a number ranging from 2 to 100, preferably a number ranging from 2 to 50 or from 5 to 25, and X represents an ethoxylated group. Also preferably according to the invention, n represents a number ranging from 2 to 100, preferably a number ranging from 2 to 50 or from 5 to 25 and X represents a propoxylated group.

[0043] According to the invention, the copolymer P is advantageously prepared, relative to the total quantity by weight of the compounds a, b and c, by means of:

[0044] * 10 mol% to 80 mol% of dihalogenated compound a;

[0045] * 5 mol% to 75 mol% of polyhydroxylated monomer b;

[0046] * 15 mol% to 85 mol% hydrophobic monoalcohol c.

[0047] Copolymer P can also be prepared by reactive extrusion, relative to the total molar quantity of compounds a, b and c, by means of:

[0048] * 15 mol% to 70 mol% of dihalogenated compound a;

[0049] * 10 mol% to 65 mol% of polyhydroxylated monomer b;

[0050] * 20 mol% to 75 mol% hydrophobic monoalcohol c.

[0051] A particular example of copolymer P can be prepared by reactive extrusion, relative to the total molar amount of compounds a, b and c, using 50 mol% of dihalogenated compound a, 20 mol% of polyhydroxy monomer b and 30 mol% of hydrophobic monoalcohol c.

[0052] Particularly advantageously, the method according to the invention can be carried out with or without a solvent, for example in a solvent chosen from water, an organic solvent and their combinations, preferably water. Preferably according to the invention, the preparation method can be carried out in the absence of a solvent.

[0053] Advantageously, the preparation method according to the invention may also comprise a final acid treatment of the copolymer P leading to a pH lower than 8, preferably to a pH higher than 6, for example by means of an acid, in particular a carboxylic acid such as acetic acid or lactic acid.

[0054] According to the invention, the reactants are generally reacted at a temperature between 70°C and 120°C. Hot water or steam may be used as a heat transfer fluid to control the temperature of the reactor in the range of 70°C to 120°C. The residence time in the reactor may be controlled, for example from less than one hour to more than six hours. A twin-screw extruder may be equipped at the end of the reactor.

[0055] The preparation method according to the invention is particularly advantageous as such but also for making it possible to obtain a particular copolymer P. Thus, the invention also relates to a copolymer P obtained according to the discontinuous preparation method defined according to the invention.

[0056] Surprisingly, the preparation method according to the invention also makes it possible to improve the viscosifying properties of the copolymer P according to the invention.

[0057] Also, the method according to the invention makes it possible to obtain P copolymers having high molar masses (Mw).

[0058] Preferably according to the invention, the molar mass (Mw) of the copolymer P may range up to 500,000 g / mol, advantageously it may vary from 8,000 to 500,000 g / mol, preferably from 20,000 to 500,000 g / mol.

[0059] The method according to the invention makes it possible to achieve polymers P with a high molar mass (Mw), advantageously varying from 120,000 to 500,000 g / mol, preferably from 150,000 to 500,000 g / mol, preferably from 150,000 to 300,000 g / mol. The method according to the invention also makes it possible to prepare copolymers P with a lower molar mass (Mw), advantageously varying from 10,000 to 150,000 g / mol, preferably from 20,000 to 150,000 g / mol, more preferably from 20,000 to 120,000 g / mol.

[0060] According to the invention, the molar mass of the copolymer P or of the compound b is determined by Size Exclusion Chromatography (SEC) or in English “Gel Permeation Chromatography” (GPC). This technique uses a “Waters” brand liquid chromatography apparatus equipped with a detector. This detector is a “Waters” 2414 type refractometric concentration detector. This liquid chromatography apparatus is equipped with two size exclusion columns in order to separate the different molecular weights of the polymers or compounds studied. The elution liquid phase is an organic phase composed of THF (HPLC grade, non-stabilized).

[0061] In a first step, approximately 25 mg of copolymer or compound is solubilized in 5 mL of THF, to which 0.1 mol% of water is added as an internal flow marker. The solution is then filtered at 0.2 pm. 50 pL is then injected into the chromatography apparatus (eluent: THF, HPLC grade, non-stabilized).

[0062] The liquid chromatography apparatus contains an isocratic pump (Waters 515) with a flow rate set at 0.3 mL / min. The chromatography apparatus also includes an oven which includes a column system in series: an Agilent PLgel MiniMIX-A column of 250 mm length and 4.6 mm diameter followed by an Agilent PLgel MiniMIX-B column of 250 mm length and 4.6 mm diameter. The detection system consists of a Waters RI 2414 refractometric detector. The columns are maintained at a temperature of 35 °C and the refractometer is heated to a temperature of 35 °C.

[0063] The chromatography device is calibrated using polymethyl methacrylate standards certified by the supplier "Agilent" ("Easivial" PMMA).

[0064] The copolymer P according to the invention can be used directly or it can be combined with other substances in a composition.

[0065] Also, the invention provides a rheological control composition comprising at least one copolymer P according to the invention. The composition according to the invention may optionally be treated in an acidic manner leading to a pH lower than 8, preferably to a pH higher than 6, for example by means of an acid, in particular a carboxylic acid such as acetic acid or lactic acid.

[0066] Preferably, in the rheological control composition according to the invention, the copolymer P according to the invention is combined with at least one solvent, in particular water or a coalescence solvent, for example glycol, butyl glycol, butyl diglycol, monopropylene glycol, ethylene glycol, ethylene diglycol, “Dowanol” products whose CAS number is 34590-94-8, “Texanol” products whose CAS number is 25265-77-4; or combined with at least one additive chosen from an amphiphilic compound, in particular a surfactant compound, preferably a hydroxylated surfactant compound, for example alkyl-polyalkylene glycol, in particular alkyl-polyethylene glycol and alkyl-polypropylene glycol; a polysaccharide derivative, for example cyclodextrin, cyclodextrin derivative, polyethers, alkyl-glucosides; a hydrotropic compound, an antifoaming agent, a biocidal agent and combinations thereof.

[0067] The invention also provides an aqueous formulation which can be used in many technical fields. The aqueous formulation according to the invention comprises:

[0068] - at least one composition according to the invention; optionally

[0069] - at least one organic or mineral pigment or organic, organo-metallic or mineral particles, for example calcium carbonate, talc, kaolin, mica, silicates, silica, metal oxides, in particular titanium dioxide, iron oxides; and optionally:

[0070] - at least one agent selected from a particle spacing agent, a dispersing agent, a steric stabilizing agent, an electrostatic stabilizing agent, an opacifying agent, a coloring agent, a solvent, a coalescing agent, an anti-foaming agent, a preservative, a biocidal agent, a spreading agent, a thickening agent, a film-forming copolymer and mixtures thereof.

[0071] Depending on the particular copolymer P or the additives it comprises, the formulation according to the invention can be implemented in many technical fields. Thus, the formulation according to the invention can be a coating formulation. Preferably, the formulation according to the invention is an ink formulation, an adhesive formulation, a varnish formulation, a paint formulation, for example decorative paint or industrial paint. The invention also provides a concentrated aqueous pigment paste comprising at least one copolymer P and at least one organic or mineral colored pigment.

[0072] The copolymer P and the formulation according to the invention have properties allowing them to be used to modify or control the rheology of the medium comprising them. Thus, the invention also provides a method for controlling the viscosity of an aqueous composition. This method for controlling the viscosity according to the invention comprises the addition of at least one copolymer P, obtained according to the invention, in an aqueous composition.

[0073] Preferably, the viscosity control method according to the invention is implemented for an aqueous composition which is a formulation according to the invention.

[0074] The advantageous, particular or preferred characteristics of the preparation method according to the invention define copolymers P, aqueous compositions, formulations, pigment pastes as well as viscosity control methods according to the invention which are also advantageous, particular or preferred.

[0075] The following examples illustrate the various aspects of the invention.

[0076] EXAMPLES

[0077] Example 1: preparation of copolymers PI to P4 according to the invention:

[0078] For the preparation of copolymers, the following compounds a, b and c are used:

[0079] - compound al: dibromomethane,

[0080] - compound bl: polyethylene glycol with a molecular mass of 8,000 g / mol,

[0081] - compound cl: hydrophobic monoalcohol of formula III in which R represents an octyldodecanyl group (branched C20-alkyl),

[0082] - compound c2: hydrophobic monoalcohol of formula III in which R represents a cardanyl group (C21 - linear aromatic alkyl) ethoxylated 4 times,

[0083] - compound c3: hydrophobic monoalcohol of formula III in which R represents a cardanyl group (C21 - linear aromatic alkyl),

[0084] - compound c4: hydrophobic monoalcohol of formula III in which R represents a 2-hexyldecanyl group (Ci6-branched alkyl). In a 2L reactor, compounds b1 and c1 are introduced, as well as sodium hydroxide (20% in water). The reaction medium is stirred for 90 min at 75°C. Compound a1 is added and the temperature is increased to 100°C. Heating is continued for 60 min. After cooling, a rheological control composition CRI according to the invention is prepared comprising copolymer PI which is introduced directly after obtaining into an aqueous composition whose final pH is adjusted to approximately 7 by means of an aqueous solution of acetic acid and which also comprises a surfactant compound (ethoxylate alcohol - Emulan HE 51 from Basf). The CRI composition comprises 20% by weight of PI copolymer, 13.3% by weight of surfactant compound and 66.7% by weight of aqueous solution comprising acetic acid.In a manner analogous to the preparation of copolymer PI and composition CR1, copolymers P2, P3 and P4 are prepared and characterized, as well as rheological control compositions CR2, CR3 and CR4 according to the invention, respectively comprising copolymer P2, P3 and P4. Compositions CR2, CR3 and CR4 respectively comprise:

[0085] - 30% by weight, 30% by weight and 20% by weight of copolymer P2, P3 or P4,

[0086] - 20% by weight, 20% by weight and 13.3% by weight of surfactant compound and

[0087] - 50% by weight, 50% by weight and 66.7% by weight of aqueous solution comprising acetic acid.

[0088] The compounds and molar quantities of the compounds used are presented in Table 1.

[0089] Table 1

[0090] Example 2: preparation and characterization of aqueous paint formulations comprising the copolymers PI and P2 according to the invention:

[0091] The compositions CRI and CR2 of copolymers PI and P2 according to the invention are used as thickening agents in a solvent-free matt paint formulation. The compositions CRI and CR2 comprising the thickening copolymers PI and P2 respectively have a solids content of 30% by weight of active material. Each paint formulation is prepared by mixing the different ingredients. The ingredients and quantities (in g) of the paint formulations are detailed in Table 2.

[0092] Table 2

[0093] For each paint formulation, the resulting viscosities are determined at different speed gradients: - at low gradient: Brookfield viscosities at 10 and 100 rpm, respectively noted VB 10 and VB 100 (mPa.s),

[0094] - medium gradient: Stormer viscosity (Krebs Unit, KU).

[0095] These measurements were taken 24 hours after preparation of the formulation. The formulations were thermostatically controlled at 25 ± 0.5°C. The results are presented in Table 3.

[0096] Table 3 The copolymers according to the invention make it possible to effectively thicken a solvent-free matte paint at different shear rates. These copolymers can be used effectively as pseudoplastic additives. In the field of aqueous paints, a high viscosity at a low or medium shear rate reflects good static behavior. This ensures good stability during storage while avoiding the phenomenon of sedimentation and limiting the tendency to run on vertical supports.

Claims

CLAIMS A discontinuous method for preparing a copolymer P comprising: * the polymerization reaction in the presence of a base: a) of at least one dihalogenated compound a of formula I: LX^ (I) in which: - L independently represents a divalent hydrocarbon group; - X 1 represents independently Br or I; b) of at least one polyhydroxylated monomer b used in a molar quantity contributing a number of hydroxyl groups (OH) less than the number of halides contributed by compound a; and * the reaction with at least one hydrophobic monoalcohol c. Preparation method according to claim 1 wherein: * the base is implemented in a molar excess relative to the molar quantity of OH groups of monomer b and monoalcohol c, preferably implemented in a molar quantity of 1.05 to 15, preferably 2 to 13, molar equivalents relative to the molar quantity of OH groups of monomer b and monoalcohol c; or * Polymerization is carried out at a pH greater than 10 or greater than 12; or * The base is a strong mineral base or a strong organic base, preferably a base selected from sodium hydride, potassium hydride, NaOH, KOH, sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide, sodium terZ-butanolate, potassium terZ-butanolate. A preparation method according to claim 1 or 2, wherein: * a single α-dihalogenated compound is used, or for which 2 or 3 different α-dihalogenated compounds are used; or * The dihalogenated compound a is a compound of formula I in which: - L independently represents a Ci-Cio-alkylene group, more preferably a Ci-C2-alkylene group, much more preferably CH2; - X 1 represents independently Br, Cl or I, preferably Br. A preparation method according to any one of claims 1 to 3, wherein: * a single polyhydroxylated compound b is used, or for which 2 or 3 different polyhydroxylated compounds b are used; or * The polyhydroxylated compound b is a compound comprising 2, 3, or 4 hydroxyl groups; or * The polyhydroxylated compound b is a compound bl of formula II: HO-Qn-OH (II) in which: - Q independently represents an oxyalkylene group, preferably chosen from oxyethylene, oxyethylene-oxypropylene comprising at most 40 mol% oxypropylene, oxyethylene-oxybutylene comprising at most 20 mol% oxybutylene, and their combinations; - n independently represents a number ranging from 20 to 800; or * the polyhydroxylated compound has a molar mass (Mw) ranging from 800 to 40,000 g / mol, preferably from 2,000 to 20,000 g / mol, more preferably from 2,000 to 15,000 g / mol. Preparation method according to any one of claims 1 to 4, wherein: * a single hydrophobic monoalcohol c is used, or for which 2 or 3 different hydrophobic monoalcohols c are used; or * The hydrophobic monoalcohol is a compound with formula III: R- X n -OH (III) in which: - R independently represents a hydrophobic hydrocarbon group, preferably a linear, branched or cyclic hydrocarbon group, saturated, unsaturated or aromatic, or comprising from 6 to 40 carbon atoms, - n represents 0 or a number from 1 to 500, - X independently represents an alkoxy group, preferably an alkoxy group selected from an ethoxy group, a propoxy group, a butoxy group, and combinations thereof. A preparation method according to any one of claims 1 to 5, wherein the copolymer P is prepared, relative to the total weight amount of compounds a, b, and c, by means of: * 10 mol% to 80 mol%, or 15 mol% to 70 mol%, for example 50 mol%, of a dihalogenated compound a; * 5% molar to 75% molar, or 10% molar to 65% molar, for example 20 molar percent, of polyhydroxylated monomer b; * 15 mol% to 85 mol%, or 20 mol% to 75 mol%, for example 30 mol%, of hydrophobic monoalcohol. A preparation method according to any one of claims 1 to 6, carried out in the absence of solvent or in a solvent selected from water, an organic solvent, and combinations thereof, preferably water. A preparation method according to any one of claims 1 to 7, further comprising a final acid treatment of the copolymer P leading to a pH below 8, preferably above 6, for example by means of an acid, in particular a carboxylic acid such as acetic acid or lactic acid. Copolymer P obtained according to the preparation method defined in any one of claims 1 to 8.Rheological control composition comprising at least one copolymer P as defined in claim 9, optionally acid-treated leading to a pH below 8, preferably above 6, for example by means of an acid, in particular a carboxylic acid such as acetic acid or lactic acid.Rheological control composition comprising at least one copolymer P as defined in claim 9 combined with at least one solvent, in particular water or a coalescing solvent, for example glycol, butyl glycol, butyldiglycol, monopropylene glycol, ethylene glycol, ethylenediglycol, "Dowanol" products of which CAS number 34590-94-8, "Texanol" products of which CAS number 25265-77-4; or combined with at least one additive selected from an amphiphilic compound, in particular a surfactant compound, preferably a hydroxylated surfactant compound, for example alkyl-polyalkyleneglycol, in particular alkyl-polyethylene glycol and alkyl-polypropyleneglycol; a polysaccharide derivative, for example cyclodextrin, derivative. cyclodextrin, polyethers, alkyl glucosides; a hydrotropic compound, an antifoaming agent, a biocidal agent, and combinations thereof. Aqueous formulation comprising: - at least one composition according to one of claims 10 or 11; possibly - at least one organic or mineral pigment or organic, organometallic or mineral particles, for example calcium carbonate, talc, kaolin, mica, silicates, silica, metal oxides, in particular titanium dioxide, iron oxides; and possibly - at least one agent selected from a particle spacer, a dispersing agent, a steric stabilizer, an electrostatic stabilizer, an opacifying agent, a coloring agent, a solvent, a coalescing agent, an antifoaming agent, a preservative, a biocide, a spreading agent, a thickening agent, a film-forming copolymer, and mixtures thereof. A coating formulation according to claim 12, in particular an ink formulation, a varnish formulation, an adhesive formulation, or a paint formulation, for example, decorative or industrial paint. A concentrated aqueous pigment paste comprising at least one copolymer P as defined in claim 9 and at least one organic or mineral colored pigment. A method for controlling the viscosity of an aqueous composition comprising the addition of at least one copolymer P as defined in claim 9 to an aqueous composition.Method according to claim 15 wherein the aqueous composition is a formulation defined according to one of claims 12 or 13.

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