CONTINUOUS PREPARATION OF HYDROPHOBIC POLYETHER COMPOUND

Abstract

The invention relates to a thickening copolymer and its continuous reactive extrusion preparation method. The preparation method first comprises a polymerization reaction of a dihalogenated compound and a polyhydroxylated monomer, followed by a reaction with a hydrophobic monoalcohol. This copolymer allows for viscosity control of an aqueous composition.

Description

Title of the invention: CONTINUOUS PREPARATION OF HYDROPHOBIC POLYETHER COMPOUND

[0001] The invention relates to a thickening copolymer and its continuous reactive extrusion preparation method. The preparation method first comprises a polymerization reaction of a dihalogenated compound and a polyhydroxylated monomer, followed by a reaction with a hydrophobic monoalcohol. This copolymer allows for viscosity control of an aqueous composition.

[0002] Many technical fields require control of the rheology of the compositions used, in particular the control of the rheology of aqueous compositions. Having a variety of effective thickening agents is therefore very useful.

[0003] Among thickening agents, a distinction is made between associative thickeners, which are generally water-soluble polymers comprising hydrophobic groups that are often insoluble in water. Such macromolecules have an associative character: once introduced into water, the hydrophobic groups are likely to assemble into micellar aggregates. These aggregates are linked together by the hydrophilic parts of the polymers. This results in the formation of a three-dimensional network that causes an increase in the viscosity of the medium.

[0004] In compositions also comprising a latex-type binding compound, thickening agents generally allow for the development of interactions with the particles of these binding compounds. Such interactions then generally increase the thickening effect. Compositions comprising a thickening polymer are usually prepared by prior synthesis of the thickening polymer using a batch process.

[0005] Generally, methods for preparing thickening compositions comprising a hydrophilic polymer, advantageously water-soluble, that are flexible and reproducible are sought. Improving the thickening efficiency of the resulting thickening agent is also desired. According to the invention, a water-soluble polymer is understood to be a polymer that is totally miscible with water at a temperature above its melting point.

[0006] Generally, for aqueous coating compositions, and particularly for aqueous paint or varnish compositions, it is necessary to control viscosity for both low and medium shear gradients as well as for high shear gradients. Indeed, during its preparation, storage, application, or drying, a paint formulation is subjected to numerous stresses requiring particularly complex rheological properties.

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

[0008] Paint pickup is the amount of paint carried by an application tool, such as a brush, roller, or paintbrush. A tool dipped and then withdrawn from the paint pot carrying a large amount of paint will prevent the need for more frequent refilling. Paint pickup is an increasing function of viscosity. The calculation of the equivalent shear gradient depends on the paint flow rate for a particular paint thickness on the tool. Therefore, the paint formulation should also have high viscosity at low or medium shear gradients.

[0009] Furthermore, a high filling power of the paint must be desired so that, when applied to a substrate, a significant amount of paint is deposited with each pass. High filling power thus allows for a thicker wet film to be obtained with each pass of the tool. A high viscosity of the paint formulation must therefore be sought at high shear gradients.

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

[0011] Hydrophobic compounds, particularly hydrophobically modified compounds such as associative non-ionic thickening agents, are known as rheology-modifying agents. However, known compounds do not always provide a satisfactory solution. Therefore, there is a need for improved rheology-modifying agents.

[0012] Furthermore, it is also important to have access to improved copolymer preparation methods. Indeed, known methods, particularly discontinuous or batch preparation methods, generate numerous problems that make them difficult to implement. It may prove impossible to efficiently implement certain thickening agent preparation methods because the problems encountered can be so difficult to overcome, especially problems related to viscosity drift in the reaction medium for preparing thickening agents.For example, the preparation of polymers by polymerization of polyethylene glycol often produces a reaction mixture whose viscosity increases significantly during the reaction, potentially leading to a sharp increase in energy consumption for stirring, heating of the reaction medium due to stirring exothermicity, or even blockage in the event of excessive viscosity drift. The preparation of such polymers therefore precludes the use of stirred reactors. The pre... Preparation of these polymers may also require significant dilution of the reaction medium with a solvent, which must then be separated. However, solvent use should always be limited or eliminated.

[0013] It is also important to have flexible preparation methods available, particularly methods that allow for varying the reagents introduced (nature, quantity) into the feed zones during synthesis. Improving the reproducibility of copolymer preparation methods should also be a priority.

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

[0015] Thus, the invention provides a method for the continuous preparation of a copolymer P by reactive extrusion comprising: * The polymerization reaction in the presence of a base: a) of at least one dihalogenated compound a; 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.

[0016] For the method according to the invention to be effective, the presence of a base is essential to allow the reaction of the polyhydroxylated monomer b with the dihalogenated compound a. Preferably according to the invention, the base is used in a molar excess relative to the molar amount of OH groups of monomer b and monoalcohol c. More preferably, the base is used in a molar amount of 1.05 to 10, preferably 1.1 to 6, molar equivalents relative to the molar amount of OH groups of monomer b.

[0017] The base used leads to an increase in pH during the implementation of the method according to the invention. Preferably, the polymerization is carried out at a pH greater than 10 or greater than 12.

[0018] According to the invention, numerous 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 selected from sodium hydride, potassium hydride, NaOH, KOH, sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide, sodium tert-butanolate, and potassium tert-butanolate. Sodium hydroxide is the preferred base.

[0019] Generally, according to the invention, the base allows the alkoxide derivative of compound b or the alkoxide derivative of monoalcohol c to be obtained. Advantageously, the treatment, total or partial, with the base of compound b or monoalcohol c, prior to carrying out the reactive extrusion, can allow the introduction directly this alkoxide derivative of compound b or this alkoxide derivative of monoalcohol c. The alkoxide derivative of compound b or the alkoxide derivative of monoalcohol c may optionally be stored separately and then introduced during the implementation of the reactive extrusion in the presence of compound a.

[0020] 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 two or three different dihalogenated compounds a. Preferably according to the invention, the dihalogenated compound a is a compound al of formula I: [Chem I] LX>2 (I) in which: - L independently represents a divalent hydrocarbon group, preferably a Ci-Cio-alkylene group, more preferably a Ci-C2-alkylene group, much more preferably CH2; - X1 independently represents Br, Cl or I, preferably Br.

[0021] Preferably, the method according to the invention also uses a single polyhydroxyl compound b or two or three different polyhydroxyl compounds b. More preferably according to the invention, the polyhydroxyl compound b is a compound comprising two, three, or four hydroxyl groups. More preferably, the polyhydroxyl compound b is a compound bl of formula II: [Chem II] HO-Qn-OH (II) wherein: - Q independently represents an oxyalkylene group, preferably selected 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.

[0022] 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%.

[0023] The preferred polyhydroxylated compound bl of formula II comprises oxyethylene Q groups. Preferably according to the invention, the polyhydroxylated compound ba a molar mass by 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).

[0024] Preferably, the method according to the invention also uses a single hydrophobic monoalcohol c or two or three different hydrophobic monoalcohols c. More preferably, the hydrophobic monoalcohol c is a compound cl of formula III: [Chem III] R-Xn-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 alkoxylated group, preferably an alkoxylated group chosen from an ethoxylated group, a propoxylated group, a butoxylated group and their combinations.

[0025] According to the invention, the hydrocarbon group R advantageously represents an alkyl or alkenyl group, linear, branched or cyclic, advantageously linear or branched, comprising from 6 to 40 carbon atoms, preferably from 6 to 32 carbon atoms.

[0026] According to the invention, the hydrocarbon group R can also include an aromatic group comprising from 6 to 40 carbon atoms, preferably from 7 to 32 carbon atoms.

[0027] According to the invention, the hydrocarbon group R may comprise a radical of formula (IV): [Chem IV] (IV) in which R” represents a hydrocarbon group of formula Ci5H3i_x in which x = 0, 2, 4, 6; thus able to include 0, 1, 2 or 3 ethy-lenic unsaturations (double bond).

[0028] Such a radical of formula (IV) is advantageously derived from cardanol, and thus of bio-sourced and non-polluting origin. According to the invention, the hydrocarbon group R may also comprise a tristyrylphenyl (TSP) group of formula: or a distyrylphenyl (DSP) group with the formula:

[0029] Preferably according to the invention, n can represent 0. The compound c is then a non-alkoxylated monoalcohol. Also preferably according to the invention, n can represent a number from 2 to 100, preferably a number from 2 to 50 or from 5 to 25.

[0030] Preferably according to the invention, X represents an ethoxylated group or a propoxylated group or a combination of ethoxylated groups and propoxylated groups.

[0031] Preferably according to the invention, n represents a number from 2 to 100, preferably a number 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 from 2 to 100, preferably a number from 2 to 50 or from 5 to 25, and X represents a propoxylated group.

[0032] According to the invention, the copolymer P is advantageously prepared by reactive extrusion, with respect to the total molar quantity of compounds a, b and c, by means of: - 10 mol% to 80 mol% of dihalogenated compound a; - 5 molar % to 75 molar % of polyhydroxylated monomer b; - 15 molar to 85 molar hydrophobic monoalcohol c.

[0033] The copolymer P can also be prepared by reactive extrusion, with respect to the total molar quantity of compounds a, b and c, by means of: - 15 mol% to 70 mol% of dihalogenated compound a; - 10 molar % to 65 molar % of polyhydroxylated monomer b; - 20 molar to 75 molar hydrophobic monoalcohol c.

[0034] A particular example of copolymer P can be prepared by reactive extrusion, with respect to the total molar amount of compounds a, b and c, using 50 mol% of dihalogenated compound a, 20 mol% of polyhydroxylated monomer b and 30 mol% of hydrophobic monoalcohol c.

[0035] Particularly advantageously, especially compared to a batch process which requires dilution of the reaction medium, 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 combinations thereof, preferably water. Preferably according to the invention, the preparation method can be carried out in the absence of a solvent.

[0036] Advantageously, the preparation method according to the invention may also include a final acid treatment of the copolymer P leading to a pH below 8, preferably to a pH above 6, for example by means of an acid, in particular a carboxylic acid such as acetic acid or lactic acid.

[0037] The preparation method according to the invention comprises the reaction by a continuous reactive extrusion process. Reactive extrusion is a method generally known for the preparation of thermoplastic polymers that have high glass transition or melting temperatures. Reactive extrusion generally allows all the steps (mixing, polymerization, and purification or devolatilization) to be carried out in the extruder. Although the polyhydroxylated compound may be heat-sensitive, no degradation is generally observed. Different types of extruders can allow the mixing of the reactants: single-screw, two-stage or co-kneader, twin-screw, planetary gear, and ring extruders. Twin-screw extruders are generally preferred.The extruder's L / D (length / diameter) ratio is adjusted according to the polymerization, polycondensation, or polyaddition time, which depends on the flow rate and residence time. The L / D ratio can, for example, be greater than or equal to 20, or more advantageously greater than or equal to 30. Implementation parameters can be adapted, including the rotation speed of the extruder screws and its design in the mixing zones, for example, according to the desired mixing.

[0038] The extruder may include one or more feeding zones. It is possible to premix the components before introducing them into the extruder. It is also possible to include in the extruder a melting zone for some of the compounds before the addition of the other compounds, in particular compound b. The extruder may include one or more heating zones. Advantageously, it includes several heating zones. The polymerization, polycondensation, or polyaddition reaction is advantageously conducted at a temperature ranging from 50°C to 350°C, more advantageously from 70°C to 300°C. The pressure can vary from 50 mbar (5 x 10³ Pa) up to 50 bar (5 MPa). The polymerization, polycondensation, or polyaddition reaction is advantageously conducted under an inert atmosphere, for example, by purging with nitrogen or argon. The method according to the invention may include one or more evaporation steps for the unreacted volatile components. The method according to the invention makes it possible to obtain the P copolymer with high conversion rates, in timeframes compatible with industrial use. Furthermore, compared to a batch reactor process, the method according to the invention allows for faster homogenization of the compounds with an increased diffusion rate and thus improved mixing.

[0039] According to the invention, the reactants are generally pumped to the reactor at a temperature between 70°C and 120°C. Hot water or steam can be used as a heat transfer fluid to control the reactor temperature within the range of 70°C to 120°C. The reactor can include separate heating zones so that different zones can be maintained at different temperatures depending on the preparation requirements of the copolymer P being prepared. Similarly, the residence time in the reactor can be controlled, for example, from less than one hour to more than six hours. A twin-screw extruder can be fitted to the end of the reactor.

[0040] The preparation method according to the invention is particularly advantageous both in itself and for enabling the production of a specific copolymer P. Thus, the invention also relates to a copolymer P obtained according to the continuous reactive extrusion preparation method defined according to the invention. Preferably, the copolymer P is in solid form at 25°C.

[0041] Surprisingly, the preparation method according to the invention also improves the viscosifying properties of the copolymer P according to the invention. Thus, the same quantity of copolymer P obtained by the method according to the invention will be thicker than an identical quantity of polymer obtained by reacting the same compounds, in the same proportions, but according to a batch process in a reactor.

[0042] The method according to the invention also makes it possible to obtain copolymers P having higher molar masses (Mw) than those of polymers that can be obtained in a batch process in a reactor, whereas the increase in viscosity would impose a maximum molar mass limit. Reactive extrusion is particularly advantageous for the preparation of copolymer P despite the sensitivity of compound b to heat. Reactive extrusion allows for time savings, with shorter cycle times compared to a batch process in a reactor. It is then possible to implement higher temperatures, for example when using polyalkylene glycols. The The risk of thermal degradation of these compounds is then reduced, in particular thanks to reduced residence times.

[0043] Preferably according to the invention, the molar mass (Mw) of the copolymer P may be up to 500,000 g / mol, advantageously it may vary from 10,000 to 500,000 g / mol, preferably from 60,000 to 500,000 g / mol.

[0044] The method according to the invention makes it possible to obtain P polymers with a high molar mass (Mw), advantageously ranging from 120,000 to 500,000 g / mol, preferably from 150,000 to 500,000 g / mol, and more preferably from 150,000 to 300,000 g / mol. The method according to the invention also makes it possible to prepare P copolymers with a lower molar mass (Mw), advantageously ranging from 10,000 to 150,000 g / mol, preferably from 60,000 to 150,000 g / mol, and more preferably from 60,000 to 120,000 g / mol.

[0045] According to the invention, the molar mass of copolymer P or compound b is determined by Size Exclusion Chromatography (SEC), also known as Gel Permeation Chromatography (GPC). This technique employs a Waters liquid chromatography system equipped with a detector. This detector is a Waters 2414 type refractometric concentration detector. This liquid chromatography system has two size exclusion columns 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, unstabilized).

[0046] In a first step, approximately 25 mg of copolymer or compound is solubilized in 5 mL of THF, to which 0.1 mol% water is added as an internal flow marker. The solution is then filtered to 0.2 µm. 50 pL is then injected into the chromatography apparatus (eluent: THF, HPLC grade, unstabilized).

[0047] The liquid chromatography apparatus includes an isocratic pump (Waters 515) with a flow rate set at 0.3 mL / min. The chromatography apparatus also includes a furnace comprising a series column system: a 250 mm long and 4.6 mm diameter Agilent PLgel MiniMIX-A column followed by a 250 mm long and 4.6 mm diameter Agilent PLgel MiniMIX-B column. The detection system consists of a Waters 2414 RI refractometer detector. The columns are maintained at 35°C and the refractometer is also heated to 35°C.

[0048] The chromatography apparatus is calibrated using polymethyl methacrylate standards certified by the supplier “Agilent” (“EasiVial” PMMA).

[0049] The copolymer P according to the invention can be used directly or it can be associated with other substances in a composition.

[0050] When used directly, the copolymer P according to the invention can be in the molten state, in particular at a temperature above its melting point and compatible with the intended use. It can also be used directly after cooling, particularly after cooling to a temperature below its melting point. It can then be used in various solid forms, for example, in a form chosen from pellets, flakes, granules, chips, powder, and combinations thereof.

[0051] The invention also provides a rheological control composition comprising at least one copolymer P according to the invention. The composition according to the invention can optionally be acidified, 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.

[0052] 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 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-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 their combinations.

[0053] The invention also provides a formulation that can be used in many technical fields. The aqueous formulation according to the invention comprises: - at least one composition according to the invention; optionally - 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 biocidal agent, a spreading agent, a thickening agent, a film-forming copolymer and mixtures thereof.

[0054] Depending on the particular copolymer P or the additives it comprises, the formulation according to the invention can be implemented in numerous technical fields. Thus, the aqueous formulation according to the invention can be a coating formulation. Preferably, the aqueous formulation according to the invention is an ink formulation, an adhesive formulation, a varnish formulation, a paint formulation, for example, a decorative paint or an industrial paint.

[0055] The invention also provides a concentrated aqueous pigment paste comprising at least one copolymer P according to the invention and at least one organic or mineral colored pigment.

[0056] The copolymer P and the formulation according to the invention possess properties that allow them to be used to modify or control the rheology of the medium containing them. Thus, the invention also provides a method for controlling the viscosity of an aqueous composition. This method of viscosity control according to the invention comprises the addition of at least one copolymer P, obtained according to the invention, to an aqueous composition.

[0057] Preferably, the viscosity control method according to the invention is implemented for an aqueous composition which is a formulation according to the invention.

[0058] 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.

[0059] The following examples illustrate the different aspects of the invention. EXAMPLES

[0060] Example 1: Preparation of PI and P2 copolymers according to the invention

[0061] A twin-screw co-rotating extruder with the following geometric parameters is used: Diameter = 26 mm and Length / Diameter ratio = 80, equipped with a gas introduction device (for example, nitrogen or depleted air) and a gas evacuation system. The tests are carried out under an uncontrolled atmosphere and at atmospheric pressure.

[0062] The twin-screw extruder has 16 independently temperature-controlled zones. These zones can be electrically heated and cooled by circulating water. Zone 1 is located below the hopper, and zone 16 corresponds to the die. The other zones are numbered 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15, in that order from zone 1 to zone 16. Each zone has a length equal to 5 screw elements. The reagents can be stored in heated, agitated, nitrogen-filled tanks equipped with pumps that allow direct injection of the reagents into the extruder. The flow rates of each pump can be independently controlled to regulate the ratios between the different reagents as well as the overall flow rate. This allows adjustment of the residence time in the extruder. Residence time can be measured by adding a colored tracer.

[0063] For the preparation of the copolymers, the following compounds a, b and c are used: - compound al: dibromomethane, - compound bl: polyethylene glycol with a molecular mass of 8,000 g / mol, - compound cl: hydrophobic monoalcohol of formula III in which R represents a linear Ci8-alkyl group, - compound c2: hydrophobic monoalcohol of formula III in which R represents a linear Ci6-alkyl group.

[0064] In a sealed tank heated to 90°C, under vacuum, and dehydrated to a water content below 800 ppm, compound bl is placed. This tank is then purged with nitrogen. Compound bl is injected into zone 1 of the extruder, which is heated to 80°C. Sodium hydroxide is also added to zone 1. Zones 2, 3, 4, and 5 of the extruder are heated to 100°C, 100°C, 150°C, and 150°C, respectively. Compound al is added to zone 6 of the extruder. Zones 6 to 9 are heated to 200°C to form a copolymer of compounds al and bl. Then, monoalcohol cl is introduced into zone 10, which is heated to 160°C. Zones 11 to 14 are maintained at this temperature. Zone 15 is cooled to 80°C. The residence time of the reaction medium in the extruder is approximately 9 minutes for a flow rate of 3 kg / h.

[0065] The PI copolymer obtained at the extruder outlet is in molten form. To obtain a rheological control composition (CRI) according to the invention, the PI copolymer is introduced directly at the extruder die outlet into an aqueous composition whose final pH is adjusted to approximately 7 using an aqueous solution of acetic acid and which also includes a surfactant compound (ethoxylate alcohol – “Emulan” HE 51 from “BASF”). The CRI composition comprises 30% by weight of PI copolymer, 20% by weight of surfactant compound, and 50% by weight of aqueous solution including acetic acid.

[0066] Similarly, the copolymer P2 and the rheological control composition CR2 according to the invention, comprising the copolymer P2, are prepared and characterized. The compounds and quantities by weight of the compounds used are presented in Table 1.

[0067] [Table 1] § Composition Compound i Sodium hydroxide | (wpolymer) | ai ( bl | cl i c2 i | CRI (PU..................[..............104.............[.......173.4......[........ÏÇ7........1..................1............HP | UU | 104î 174.3 ]__________i HL5 ji ij

[0068] Example 2: Preparation and characterization of aqueous paint formulations comprising PI and P2 copolymers according to the invention

[0069] The CRI and CR2 compositions of PI and P2 copolymers according to the invention are used as a thickening agent in a solvent-free matte paint formulation. The CRI and CR2 compositions, comprising the thickening PI and P2 copolymers respectively, have a dry extract 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.

[0070] [Table 2] Ingredients of the aqueous paint formulation Quantity (g) “Ecodis” P50 (dispersant “Coatex”) 2.00 “Tego” 810 (anti-foam “Tego”) 0.51 Actleide MBS (bactericide “Thor”) 1.00 TiONa 568 (TiOj “Troues.”) 40.01 “Omwcoat” 850 OG (CaCO3 “Omya”) 110.00 “Durcal” 2 AV (CaCO3 “Omya”) 150.29 “Acronal” S79O (binder “Basf”) 65.00 Monopropylene glycol 5.06 “Texanol (coalescent agent “Eastman”) 5.02 NaOH (20% by weight in water) 0.41 Composition CRI or CR2 (3.0% by weight of PI or P2) 4.70 Water H600 Total 500.00

[0071] For each paint formulation, the resulting viscosities are determined at different velocity gradients: - at low gradient: Brookfield viscosities at 10 and 100 rpm, respectively denoted VB100 and VB100 (mPa.s), - at medium gradient: Stormer viscosity (Krebs Unit, KU).

[0072] These measurements are taken 24 hours after preparation of the formulation. The formulations are thermostated at 25 ± 0.5°C. The results are presented in Table 3.

[0073] [Tab.3] i iç&poiy mothers) VBÎ0(mPa,$H VB jOum-JUViscosity Stormer (KU) it El UT> W 700 i 5 1^5 i 123 <. R2 d'Il 4,300 i 2,000 §9

[0074] The copolymers according to the invention make it possible to effectively thicken a solvent-free matte paint at various shear gradients. These copolymers can be used effectively as pseudoplastic additives.

[0075] In the field of water-based paints, a high viscosity at a low or medium shear gradient indicates good static behavior. This ensures good stability during storage while preventing sedimentation and limiting the tendency to run on vertical surfaces.

Claims

Demands

1. Method of continuous preparation of a copolymer P by reactive extrusion comprising: * the polymerization reaction in the presence of a base of: a) at least one dihalogenated compound a; b) at least one polyhydroxylated monomer b used in a molar quantity providing a number of hydroxyl groups (OH) less than the number of halides provided by compound a; and * the reaction with at least one hydrophobic monoalcohol c.

2. A preparation method according to claim 1 wherein: - the base is used in a molar excess relative to the molar amount of OH groups of monomer b and monoalcohol c, preferably used in a molar amount of 1.05 to 10, preferably 1.1 to 6 molar equivalents relative to the molar amount of OH groups of monomer b; or - the 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 tert-butanolate, potassium tert-butanolate.

3. A preparation method according to any one of claims 1 or 2 wherein: * a single dihalogenated compound a is used or wherein 2 or 3 different dihalogenated compounds a are used; or * the dihalogenated compound a is a compound al of formula I: [Chem I] lx*2 (I) in which: - L independently represents a divalent hydrocarbon group, preferably a Ci-Cio-alkylene group, more preferably a Ci-C2-alkylene group, much more preferably CH2; - X1 independently represents Br, Cl or I, preferably Br.

4. 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: [Chem 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 mass 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.

5. A 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 * hydrophobic monoalcohol c is a compound cl of formula III: [Chem III] R-Xn-OH (HD 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 alkoxylated group, preferably an alkoxylated group chosen from an ethoxylated group, a propoxylated group, a butoxylated group and their combinations.

6. A preparation method according to any one of claims 1 to 5, wherein the copolymer P is prepared by reactive extrusion, compared to the total molar quantity 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 dihalogenated compound a; - 5 mol% to 75 mol% or 10 mol% to 65 mol%, for example 20 mol%, of polyhydroxylated monomer b; - 15 mol% to 85 mol% or 20 mol% to 75 mol%, for example 30 mol%, of hydrophobic monoalcohol c.

7. 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.

8. A preparation method according to any one of claims 1 to 7 also 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.

9. Copolymer P obtained according to the continuous preparation method by reactive extrusion defined according to any one of claims 1 to 8, preferably in molten form or in solid form at 25 °C or at a temperature below its melting point, for example in a solid form selected from pellet, flake, ground, chip, powder and combinations thereof.

10. Rheological control composition comprising at least one copolymer P according to 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.

11. Rheological control composition according to claim 10 comprising at least one copolymer P according to any one of claims 1 to 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 CAS number 34590-94-8, "Texanol" products of CAS number 25265-77-4; or combined with at least one additive selected from an amphiphilic compound, in particular a surfactant, preferably a hydroxylated surfactant, 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 their combinations.

12. Aqueous formulation comprising: - at least one composition according to any one of claims 10 or 11; optionally - 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 optionally - 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 biocidal agent, a spreading agent, a thickening agent, a film-forming copolymer and mixtures thereof.

13. Formulation according to claim 12 of coating, in particular an ink formulation, a varnish formulation, an adhesive formulation, a paint formulation, for example decorative paint or industrial paint.

14. Concentrated aqueous pigment paste comprising at least one copolymer P according to any one of claims 1 to 9 and at least one organic or mineral colour pigment.

15. Method for controlling the viscosity of an aqueous composition comprising the addition of at least one copolymer P according to any one of claims 1 to 9 in an aqueous composition.

16. Method according to claim 15 wherein the aqueous composition is a formulation defined according to one of claims 12 or 13.