Polyitaconic composition

Abstract

The invention relates to an aqueous polymer composition comprising a water-soluble sulphonated polymer which is prepared with a radical polymerization reaction in water in the presence of a compound comprising sulphur in oxidation state IV. The invention also relates to this preparation method and to a dispersing or grinding agent comprising the composition according to the invention.

Description

[0001] POLYITACONIC COMPOSITION

[0002] The invention relates to an aqueous polymer composition comprising a water-soluble sulfonated polymer which is prepared by a radical polymerization reaction in water in the presence of a compound comprising sulfur in oxidation state IV. The invention also relates to this method of preparation as well as to a dispersing or grinding agent comprising the composition according to the invention.

[0003] Many technical fields require the use of polymers chosen for their specific properties. In particular, the field of mineral processing, particularly the dispersion or grinding of mineral matter, uses dispersing agents or grinding aids. Also, the fields of water treatment and detergents use polymers capable of developing interactions with mineral matter.

[0004] The methods of preparing these polymers play an essential role in their effectiveness but also in their implementation conditions, in particular when it comes to limiting or banning the use of polluting or dangerous substances.

[0005] The methods for preparing these polymers also play a key role when they allow the use of compounds of renewable or non-fossil origin, in particular compounds of natural origin. These preparation methods should not use volatile organic compounds, in particular alkanes, aromatic hydrocarbon compounds or achenes. In particular, the presence of such compounds should be controlled to avoid their release during the use of these polymers.

[0006] Furthermore, it should be possible to prepare these polymers in the absence of any compound that may be considered environmentally harmful or in the absence of any compound whose use is restricted by regulatory provisions. In particular, the preparation of these polymers in the absence of any compound containing phosphorus should be preferred, particularly in the absence of phosphorus in oxidation states I, III or V.

[0007] The general economy of the methods for preparing these polymers also plays a very important role, both with regard to the yield of the polymerization reaction or the conversion rate of the reactants and with regard to the control of the quantities of by-products formed. In particular, these methods should make it possible to control or reduce the quantities of by-products which are detrimental to the properties of the polymers formed. Preferably, these methods should make it possible to control or reduce the quantities of oligomers formed. They should also make it possible to reduce the quantities of residual monomers present at the end of the polymerization reaction.

[0008] EP 0079165 discloses a method for preparing copolymers of (meth)acrylic acid and itaconic acid. EP 2796481 also discloses a method for preparing copolymers that are prepared using (meth)acrylic acid and sodium alkenyl sulfonate. WO 2018191326 describes a composition comprising 2 copolymers of itaconic acid and a sulfonate in respective inverse proportions in each of the copolymers. Thus, there is a significant need for efficient polymers that can be prepared by improved methods. Control of the molecular weight and the polydispersity index of the polymers is also sought. State-of-the-art polymers and their preparation methods are not always satisfactory for providing a solution to all or part of the problems encountered.

[0009] Thus, the invention provides an aqueous polymeric composition C comprising at least one water-soluble sulfonated polymer P, of molecular mass Mw, measured by CES, ranging from 1,500 g / mol to 50,000 g / mol and prepared by a radical polymerization reaction in water of at least one compound Ml chosen from sodium itaconate, potassium itaconate, lithium itaconate, ammonium itaconate, calcium itaconate, magnesium itaconate and combinations thereof, in the presence of at least one initiator compound and at least one sulfur compound T comprising sulfur in oxidation state IV (sulfur IV or S IV ) and selected from lithium hydrogen sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, ammonium hydrogen sulfite, calcium di(hydrogen sulfite), magnesium di(hydrogen sulfite) and combinations thereof.

[0010] Generally, composition C according to the invention comprises a quantity by weight of water which is less than 70%, preferably less than 65% or 60%, more preferably less than 55% or 50%, relative to the quantity by weight of all the other compounds present, in particular relative to the quantity by weight of polymer P.

[0011] Essentially according to the invention, the polymer P is prepared by a radical polymerization reaction in the presence of the sulfur compound T which comprises sulfur in oxidation state IV (sulfur IV or S IV ). Thus, the polymer P according to the invention is a sulfonated or sulfitaconic polymer. Preferably according to the invention, the polymer P is a sulfo-polyitaconic polymer. Also preferably according to the invention, the polymer P is an α-co-sulfonated polyitaconic polymer.

[0012] Preferably, the composition C according to the invention comprises a polymer P which has a molecular mass Mw, measured by CES, ranging from 2,000 g / mol to 50,000 g / mol or from 1,500 g / mol to 40,000 g / mol, preferably from 2,000 g / mol to 25,000 g / mol or

[0013] 1,500 g / mol to 20,000 g / mol. More preferably, the polymer P has a molecular mass Mw ranging from 2,000 g / mol to 20,000 g / mol, even more preferably from

[0014] 2,000 g / mol to 15,000 g / mol, much more preferably from 3,000 g / mol to 13,000 g / mol or from 2,500 g / mol to 15,000 g / mol, particularly preferably from 3,500 g / mol to 20,000 g / mol or from 3,000 g / mol to 15,000 g / mol, most preferably from 3,500 g / mol to 15,000 g / mol or from 3,500 g / mol to 13,000 g / mol, and much more preferably from

[0015] 3,500 g / mol to 10,000 g / mol or from 3,500 g / mol to 8,000 g / mol or from 3,500 g / mol to 6,500 g / mol or from 3,500 g / mol to 5,500 g / mol.

[0016] According to the invention, the molecular weight or mass of the polymer P as well as the polymolecularity index are determined by Size Exclusion Chromatography (SEC). A test sample of the polymer dispersion corresponding to 90 mg of dry matter is introduced into a 10 mL flask. Mobile phase, supplemented with 0.04% dimethylformamide (DMF), is added up to a total mass of 10 g. The composition of this mobile phase is as follows: NaHCOs: 0.05 mol / L, NaNOs: 0.1 mol / L, triethanolamine: 0.02 mol / L, NaNs: 0.03% by mass.The CES chain is composed of a "Waters" 510 isocratic pump, whose flow rate is set at 0.8 mL / min, a "Waters" 717+ sample changer, an oven containing a "Guard Column Ultrahydrogel Waters" precolumn of 6 cm length and 40 mm inner diameter, followed by a linear column of "Ultrahydrogel Waters" of 30 cm length and 7.8 mm inner diameter. Detection is ensured by means of a differential refractometer of "RI Waters" 410 type. The oven is brought to the temperature of 60 ° C and the refractometer is brought to the temperature of 45 ° C. The CES device is calibrated with a series of sodium polyacrylate standards supplied by "Polymer Standard Service" with peak molecular weights between 900 g / mol and 2,250,000 g / mol and polydispersity index between 1.4 and 1.7.The calibration curve is linear and takes into account the correction obtained using the flow marker: dimethylformamide (DMF). The acquisition and processing of the chromatogram are carried out using the software “PSS WinGPC Scientific” v 4.02. The chromatogram obtained is integrated into the area corresponding to molecular weights greater than 250 g / mol.

[0017] The method for preparing composition C according to the invention is particularly effective, in particular for controlling the properties of polymer P. Thus, preferably, composition C according to the invention comprises a polymer P whose polymolecularity index (Pl), measured by CES, is less than 5.5, preferably less than 4.5 or less than 4. More preferably, the polymolecularity index of polymer P is less than 3. Also preferably according to the invention, the polymolecularity index of polymer P ranges from 1.6 to 5.5, more preferably from 1.6 to 4.5 or ranging from 1.6 to 4, much more preferably from 1.6 to 3.

[0018] Preferably according to the invention, the polymer P is totally or partially neutralized. More preferably, the polymer P is neutralized by means of an ion chosen from a monovalent ion, a divalent ion and their combinations, much more preferably by means of an ion chosen from K + , N / A+ , Li + , NHÉ, Mg 2+ , That 2+ and combinations thereof. Also preferably, the polymer P is totally or partially neutralized by means of at least one compound chosen from LiOH, NaOH, KOH, Zn(OH)2, Mg(OH)2, Ca(OH)2, ZnO, MgO, CaO, ammonium derivatives, ammonia, aqueous ammonia, amine bases, for example triethanolamine, aminomethylpropanol or 2-amino-2-methyl-propanol (AMP), and combinations thereof. The preferred compounds according to the invention are chosen from NaOH, Ca(OH)2, CaO and combinations thereof.

[0019] Essentially according to the invention, the polymer P is prepared using the compound ML. Preferably, the compound M1 is chosen from itaconic acid, sodium itaconate, potassium itaconate, lithium itaconate, ammonium itaconate and combinations thereof. More preferably, the compound M1 is chosen from itaconic acid, sodium itaconate and combinations thereof. More preferably according to the invention, the polymer P is a homopolymer.

[0020] According to the invention, the polymer P can also be prepared using at least one other compound different from the compound ML. Then, the polymer P is prepared using a combination of compound M1 and another different compound. Preferably, the polymer P is then prepared using 0.5% by weight to 30% by weight of another compound relative to the total amount by weight of monomers.

[0021] Preferably according to the invention, the polymer P can be prepared using at least one compound chosen from itaconic anhydride, itaconic acid and their combinations.Also preferably according to the invention, the polymer P may be prepared by means of another compound selected from a compound M2 selected from acrylic acid, methacrylic acid, an acrylic acid oligomer, a methacrylic acid oligomer, an acrylic acid salt, a methacrylic acid salt, an acrylic acid oligomer salt, a methacrylic acid oligomer salt, maleic acid, maleic anhydride, crotonic acid, 2-acrylamido-2-methylpropane sulfonic acid, a salt of 2-acrylamido-2-methylpropane sulfonic acid, ethoxymethacrylate sulfonic acid, sodium methallyl sulfonate, styrene sulfonate, phosphated hydroxyethylacrylate, phosphated hydroxyethylmethacrylate, phosphated hydroxypropylacrylate, phosphated hydroxypropylmethacrylate, phosphated hydroxybutylacrylate, phosphated hydroxybutyl methacrylate and combinations thereof.Preferably, compound M2 is selected from acrylic acid, methacrylic acid, an acrylic acid oligomer, a methacrylic acid oligomer, an acrylic acid salt, a methacrylic acid salt, an acrylic acid oligomer salt, a methacrylic acid oligomer salt, maleic acid, maleic anhydride, 2-acrylamido-2-methylpropane sulfonic acid, a 2-acrylamido-2-methylpropane sulfonic acid salt and combinations thereof.

[0022] Also preferably according to the invention, the polymer P may be prepared using another compound selected from a compound M3 independently selected from C1-C12 esters of methacrylic acid, C1-C12 esters of acrylic acid, acrylamide, styrene, t-Bu-acrylamide, alkylacrylamides, N-methylolacrylamide, acrylonitrile, vinyl lactam, N-vinylpyrrolidone, ureidomethacrylate, hydroxyethylacrylate, hydroxyethylmethacrylate, hydroxypropylacrylate, hydroxypropylmethacrylate, hydroxybutylmethacrylate, hydroxybutylacrylate, caprolactone methacrylate, caprolactone acrylate, polycaprolactone methacrylate, polycaprolactone acrylate, lactam methacrylate, lactam acrylate, polycaprolactam methacrylate, polycaprolactam acrylate, vinyl acetate and combinations thereof; preferably C1-C8 esters of methacrylic acid, C1-C8 esters of acrylic acid and combinations thereof;preferably styrene, t-Bu-acrylamide, methylmethacrylate, ethylmethacrylate, propylmethacrylate, butylmethacrylate, methylacrylate, ethyl acrylate, propyl acrylate, butyl acrylate, more preferably, methylmethacrylate, methylacrylate, ethyl acrylate, butylacrylate and combinations thereof. According to the invention, the preferred compounds M3 are chosen from t-Bu-acrylamide, ethylacrylate and combinations thereof. Preferably according to the invention, the polymer P is not decarboxylated, in particular by releasing carbon dioxide. Also preferably according to the invention, the polymer P is prepared in the absence of a phosphorus compound, in particular in the absence of a compound comprising phosphorus I or in the absence of a compound comprising phosphorus III, in particular in the absence of hypophosphorous acid, a compound comprising hypophosphite, phosphorous acid or a compound comprising phosphite.;

[0023] Essentially according to the invention, the polymer P is prepared in the presence of at least one particular sulfur compound T comprising sulfur in oxidation state IV (sulfur IV or S IV ). Preferably according to the invention, compound T is chosen from sodium hydrogen sulfite, potassium hydrogen sulfite, calcium di(hydrogen sulfite) and combinations thereof. The preferred compound T is sodium hydrogen sulfite. When preparing the polymer P according to the invention, the amount of compound T can vary. Preferably according to the invention, compound T is used in an amount of 0.5% by weight to 15% by weight, preferably 1% by weight to 10% by weight, more preferably 1.5% by weight to 8% by weight, relative to the total amount by dry weight of monomers used during the polymerization reaction.

[0024] According to the invention, the polymerization reaction is preferably carried out at a temperature above 30°C and below 100°C, preferably below 90°C, more preferably below 80°C or 75°C.

[0025] Essentially according to the invention, the polymer P is prepared in the presence of at least one initiator compound. Preferably according to the invention, the initiator compound is chosen from a peroxide (for example hydrogen peroxide, / c / V-butyl hydroperoxide), a persulfate (for example sodium persulfate, ammonium persulfate, potassium persulfate), their combinations and their associations with a metal salt, preferably a metal salt chosen from an iron salt (for example Fe 11 or Fe 111 ), a copper salt (e.g. Cu 1 or Cu 11 ) and their combinations.

[0026] The preferred initiator compound is selected from a peroxide, in particular hydrogen peroxide, / c / V-butyl hydroperoxide and their combinations and associations with a metal salt, preferably a metal salt selected from an iron salt (for example Fe 11 or Fe 111 ), a copper salt (e.g. Cu 1 or Cu 11 ) and their combinations.

[0027] Preferably, during the polymerization reaction according to the invention, the compound M1 is used in a particular manner in order to obtain the polymer P. Particularly preferably, during the preparation of the composition C according to the invention, the compound M1 is present during the polymerization reaction in an amount by weight greater than 30%, much more preferably greater than 35% or 40%, relative to all the compounds present in the reaction medium. More preferably, according to the invention, the compound M1 is present during the polymerization reaction in an amount by weight greater than 45% or 50%, relative to all the compounds present in the reaction medium.

[0028] The preparation of composition C according to the invention comprises several steps. In particular, the preparation of composition C according to the invention comprises a step of preparing the reaction medium which comprises compound M1, in particular the preparation of the bottom of the tank when using a radical polymerization reactor. Preferably according to the invention, the reactor is chosen from a tubular reactor and a stirred tank. The preparation method also comprises a step of introducing the initiator compound and a step of introducing compound T and heating the reaction medium.

[0029] During the different steps, the presence and the quantities of the different compounds may vary. Preferably, during the preparation of composition C according to the invention, the polymerization reaction comprises: the preparation of a reaction medium comprising at least one compound M1 in an amount by weight greater than 35%, preferably greater than 50% or 60%, more preferably greater than 65% or 70%, relative to all the reactants of this reaction medium, then the addition of the initiator compound, of the compound T, and optionally of the compound M1 and the heating of the reaction medium.

[0030] The polymer P according to the invention is prepared according to particular reaction conditions which make it possible to obtain a composition C with particularly advantageous properties, in particular to obtain a composition C comprising a limited quantity of oligomers of compound M1 or oligomers of compound M1 and at least one compound M2 or M3. Preferably according to the invention, the composition C according to the invention comprises small quantities of such oligomers whose molecular mass Mw, measured by CES, is less than 1000 g / mol.

[0031] More preferably according to the invention, composition C comprises less than 30% by weight, preferably less than 25% by weight or less than 20% by weight, of oligomers of compound Ml having a molecular mass Mw, measured by CES, of less than 1000 g / mol relative to the quantity of polymer P.

[0032] Also more preferably according to the invention, composition C comprises less than 30% by weight, preferably less than 25% by weight or less than 20% by weight, of oligomers of compound M1 and of at least one compound M2 or M3, and having a molecular mass Mw, measured by CES, of less than 1000 g / mol relative to the quantity of polymer P.

[0033] The invention also relates to the method for preparing composition C according to the invention. Preferably, the method for preparing a composition C according to the invention comprises: the preparation of a reaction medium comprising at least one compound M1 in an amount by weight greater than 35%, preferably greater than 50% or 60%, more preferably greater than 65% or 70%, relative to all the reactants of the reaction medium, then the addition of the initiator compound, of the compound T, and optionally of the compound M1 and the heating of the reaction medium.

[0034] The preparation method according to the invention is particularly effective for the preparation of a water-soluble sulfonated polymer P. In particular, this preparation method makes it possible to obtain a composition C in which the quantities of residual monomers, in particular of residual monomer M1, are low. According to the invention, the quantities of residual monomers are measured at the end of the polymerization reaction by high-performance liquid chromatography (HPLC) and expressed in % by weight (dry / dry) relative to the quantity of reagents used during the polymerization reaction.Preferably according to the invention, the aqueous composition C comprises less than 5% by weight, more preferably less than 3% by weight or less than 2% by weight, more preferably less than 1.5% by weight or less than 1% by weight, measured by HPLC, of ​​residual monomers, preferably of monomer M1 and optionally of monomers M2 and M3, relative to the quantity of reagents used during the polymerization reaction.

[0035] The preparation method according to the invention makes it possible to obtain a composition C which has particularly interesting properties in different fields. Thus, the invention also provides a dispersing or grinding agent comprising at least one composition C according to the invention. The dispersing or grinding agent according to the invention may also comprise at least one liquid or solid support or at least one additive. The advantageous, particular or preferred characteristics of the composition C according to the invention define preparation methods and dispersing or grinding agents which are also advantageous, particular or preferred.

[0036] The various aspects of the invention may be illustrated by examples.

[0037] EXAMPLES

[0038] Preparation of a composition Cl according to the invention comprising the polymer PI

[0039] In a glass reactor, 207 g of itaconic acid (compound Ml) are introduced, and

[0040] 127.38 g of a 50% by mass aqueous sodium hydroxide solution. The reaction is exothermic, the reactor temperature is maintained at 97°C + / - 2°C then 0.04 g of iron sulfate heptahydrate and 10 g of deionized water are introduced.

[0041] In a first beaker, weigh 27.3 g of hydrogen peroxide in a 35% mass solution and 27 g of deionized water. In a second beaker, weigh 25 g of sodium bisulfite in an aqueous solution at 40% mass.

[0042] The reagents from the 2 beakers are introduced in parallel into the reactor for 2 hours and the temperature is maintained at 97°C + / - 2°C. Then, 150 g of deionized water are added and the medium is allowed to cool to room temperature. Composition C1 is obtained, comprising the copolymer PI according to the invention at 50.6% by weight of dry extract, the composition and characteristics of which are detailed in Table 1.

[0043] Preparation of a composition C2 according to the invention comprising the polymer P2

[0044] In a glass reactor, 207 g of itaconic acid (compound Ml) are introduced, and

[0045] 127.39 g of a 50% by mass aqueous sodium hydroxide solution. The reaction is exothermic, the reactor temperature is maintained at 97°C + / -2°C then 0.04 g of iron sulfate heptahydrate and 10 g of deionized water are introduced.

[0046] In a first beaker, weigh 40.95 g of hydrogen peroxide in a 35% mass solution and 27 g of deionized water. In a second beaker, weigh 25 g of sodium bisulfite in an aqueous solution at 40% mass.

[0047] The reagents from the 2 beakers are introduced in parallel into the reactor for 2 hours and the temperature is maintained at 97°C + / - 2°C. Then, 150 g of deionized water are added and the medium is allowed to cool to room temperature. Composition C2 is obtained comprising the copolymer P2 according to the invention at 50.2% by weight of dry extract, the composition and characteristics of which are detailed in Table 1. Preparation of a composition C3 according to the invention comprising the polymer P3

[0048] In a glass reactor, 207 g of itaconic acid (compound Ml) are introduced, 127.39 g of a 50% by mass aqueous sodium hydroxide solution are added. The reaction is exothermic, the reactor temperature is maintained at 97°C + / -2°C then 0.04 g of iron sulfate heptahydrate and 10 g of deionized water are introduced.

[0049] In a first beaker, weigh 40.95 g of hydrogen peroxide in a 35% mass solution and 27 g of deionized water. In a second beaker, weigh 15 g of sodium bisulfite in an aqueous solution at 40% mass.

[0050] The reagents from the 2 beakers are introduced in parallel into the reactor for 2 hours and the temperature is maintained at 97°C + / - 2°C. Then, 150 g of deionized water are added and the medium is allowed to cool to room temperature. Composition C3 is obtained, comprising the copolymer P3 according to the invention at 50.4% by weight of dry extract, the composition and characteristics of which are detailed in Table 1.

[0051] Preparation of a composition C4 according to the invention comprising the polymer P4

[0052] In a glass reactor, 207 g of itaconic acid (compound Ml) are introduced, 127.39 g of a 50% by mass aqueous sodium hydroxide solution are added. The reaction is exothermic, the reactor temperature is maintained at 90°C + / -2°C.

[0053] In a first beaker, weigh 27.3 g of hydrogen peroxide in a 35% mass solution and 27 g of deionized water. In a second beaker, weigh 25 g of sodium bisulfite in an aqueous solution at 40% mass.

[0054] The reagents from the 2 beakers are introduced in parallel into the reactor for 2 hours and the temperature is maintained at 90°C + / - 2°C. Then, 150 g of deionized water are added and the medium is allowed to cool to room temperature. Composition C4 is obtained, comprising the copolymer P4 according to the invention at 51.5% by weight of dry extract, the composition and characteristics of which are detailed in Table 1.

[0055] Preparation of a composition C5 according to the invention comprising the polymer P5

[0056] In a glass reactor, 207 g of itaconic acid (compound Ml) are introduced, 127.38 g of a 50% by mass aqueous sodium hydroxide solution are added. The reaction is exothermic, the reactor temperature is maintained at 90°C + / -2°C then 0.02 g of iron sulfate heptahydrate and 10 g of deionized water are introduced.

[0057] In a first beaker, weigh 27.3 g of hydrogen peroxide in a 35% mass solution and 27 g of deionized water. In a second beaker, weigh 25 g of sodium bisulfite in an aqueous solution at 40% mass.

[0058] The reagents from the 2 beakers are introduced in parallel into the reactor for 2 hours and the temperature is maintained at 90°C + / - 2°C. Then, 150 g of deionized water are added and the medium is allowed to cool to room temperature. Composition C5 is obtained, comprising the copolymer P5 according to the invention at 50.6% by weight of dry extract, the composition and characteristics of which are detailed in Table 1.

[0059] Preparation of a composition C6 according to the invention comprising the polymer P6

[0060] In a glass reactor, 207 g of itaconic acid (compound Ml) are introduced, and

[0061] 127.38 g of a 50% by mass aqueous sodium hydroxide solution. The reaction is exothermic, the reactor temperature is maintained at 90°C + / -2°C.

[0062] In a first beaker, weigh 10.35 g of sodium persulfate and 27 g of deionized water. In a second beaker, weigh 25 g of sodium bisulfite in aqueous solution at 40% by mass.

[0063] The reagents from the 2 beakers are introduced in parallel into the reactor for 2 hours and the temperature is maintained at 90°C + / - 2°C. Then, 150 g of deionized water are added and the medium is allowed to cool to room temperature. Composition C6 is obtained, comprising the copolymer P6 according to the invention at 53.2% by weight of dry extract, the composition and characteristics of which are detailed in Table 1.

[0064] Preparation of a composition C7 according to the invention comprising the polymer P7

[0065] In a glass reactor, 207 g of itaconic acid (compound Ml) are introduced, and

[0066] 127.39 g of a 50% by mass aqueous sodium hydroxide solution. The reaction is exothermic, the reactor temperature is maintained at 97°C + / -2°C then 0.0159 g of iron sulfate heptahydrate, 0.0186 g of copper sulfate pentahydrate and 10 g of deionized water are introduced.

[0067] In a first beaker, weigh 27.3 g of hydrogen peroxide in a 35% mass solution and 27 g of deionized water. In a second beaker, weigh 25 g of sodium bisulfite in an aqueous solution at 40% mass.

[0068] The reagents from the 2 beakers are introduced into the reactor for 2 hours and the temperature is maintained at 97°C + / - 2°C. Then, 150 g of deionized water are added and the medium is allowed to cool to room temperature. Composition C7 is obtained, comprising the copolymer P7 according to the invention at 53.1% by weight of dry extract, the composition and characteristics of which are detailed in Table 1.

[0069] Preparation of a composition C8 according to the invention comprising the polymer P8

[0070] In a glass reactor, 207 g of itaconic acid (compound Ml) are introduced, 127.38 g of a 50% by mass aqueous sodium hydroxide solution are added. The reaction is exothermic, the reactor temperature is maintained at 97°C + / -2°C then 0.02 g of iron sulfate heptahydrate and 10 g of deionized water are introduced.

[0071] In a first beaker, 27.3 g of hydrogen peroxide in a 35% mass solution and 27 g of deionized water are weighed. In a second beaker, 25 g of sodium bisulfite in an aqueous solution at 40% mass are weighed. The reagents from the 2 beakers are introduced in parallel into the reactor for 2 hours and the temperature is maintained at 97°C + / - 2°C. Then, 150 g of deionized water are added and the medium is allowed to cool to room temperature. Composition C8 is obtained comprising the copolymer P8 according to the invention at 50.6% by weight of dry extract, the composition and characteristics of which are detailed in Table 1.

[0072] Table 1

[0073] The invention makes it possible to obtain, in a particularly efficient manner and with very good conversion rates, compositions C of itaconate polymers P which comprise very small quantities of residual monomers or unwanted oligomers.

Claims

CLAIMS 1. Aqueous polymeric composition C comprising at least one water-soluble sulfonated polymer P, of molecular mass Mw, measured by CES, ranging from 1,500 g / mol to 50,000 g / mol and prepared by a radical polymerization reaction in water of at least one compound Ml chosen from sodium itaconate, potassium itaconate, lithium itaconate, ammonium itaconate, calcium itaconate, magnesium itaconate and combinations thereof, in the presence of at least one initiator compound and at least one sulfur compound T comprising sulfur in oxidation state IV (sulfur IV or S IV ) and selected from lithium hydrogen sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, ammonium hydrogen sulfite, calcium di(hydrogen sulfite), magnesium di(hydrogen sulfite) and combinations thereof.

2. Composition C according to claim 1 for which the polymer P has a molecular mass Mw, measured by CES, ranging from 2,000 g / mol to 50,000 g / mol or from 1,500 g / mol to 40,000 g / mol, preferably from 2,000 g / mol to 25,000 g / mol or from 1,500 g / mol to 20,000 g / mol, more preferably from 2,000 g / mol to 20,000 g / mol, even more preferably from 2,000 g / mol to 15,000 g / mol, much more preferably from 3,000 g / mol to 13,000 g / mol or from 2,500 g / mol to 15,000 g / mol, particularly preferably from 3,500 g / mol to 20,000 g / mol or from 3,000 g / mol to 15,000 g / mol, most preferably from 3,500 g / mol to 15,000 g / mol or from 3,500 g / mol to 13,000 g / mol, and much more preferably from 3,500 g / mol to 10,000 g / mol or from 3,500 g / mol to 8,000 g / mol or from 3,500 g / mol to 6,500 g / mol or from 3,500 g / mol to 5,500 g / mol.

3. Composition C according to one of claims 1 or 2 for which: the polymer P has a polymolecularity index (Ip), measured by CES, of less than 5.5, preferably less than 4.5 or less than 4, more preferably less than 3; or the polymer P has a polymolecularity index, measured by CES, ranging from 1.6 to 5.5, preferably ranging from 1.6 to 4.5 or ranging from 1.6 to 4, more preferably ranging from 1.6 to 3; or the polymer P is totally or partially neutralized, preferably by means of an ion chosen from a monovalent ion, a divalent ion and their combinations, more preferably by means of an ion chosen from K + , N / A + , Li + , NEW + , Mg 2+ , That 2+and combinations thereof; also preferably, the polymer P is totally or partially neutralized by means of at least one compound chosen from LiOH, NaOH, KOH, Zn(OH)2, Mg(OH)2, Ca(OH)2, ZnO, MgO, CaO, ammonium derivatives, ammonia, aqueous ammonia, amine bases, for example triethanolamine, aminomethylpropanol or 2-amino-2-methyl-propanol (AMP), and combinations thereof, more preferably NaOH, Ca(OH)2, CaO and combinations thereof.

4. Composition C according to one of claims 1 to 3 for which: the polymer P is also prepared using at least one other compound different from the compound M1, preferably from 0.5% by weight to 30% by weight of another compound relative to the total quantity by weight of monomers; or the polymer P is also prepared using at least one compound chosen from itaconic anhydride, itaconic acid and their combinations; or the polymer P is also prepared using another compound chosen from: • a compound M2 selected from acrylic acid, methacrylic acid, an acrylic acid oligomer, a methacrylic acid oligomer, an acrylic acid salt, a methacrylic acid salt, an acrylic acid oligomer salt, a methacrylic acid oligomer salt, maleic acid, maleic anhydride, crotonic acid, 2-acrylamido-2-methylpropane sulfonic acid, a 2-acrylamido-2-methylpropane sulfonic acid salt, ethoxymethacrylate sulfonic acid, sodium methallyl sulfonate, styrene sulfonate, phosphated hydroxyethylacrylate, phosphated hydroxyethylmethacrylate, phosphated hydroxypropylacrylate, phosphated hydroxypropylmethacrylate, phosphated hydroxybutylacrylate, phosphated hydroxybutylmethacrylate and combinations thereof; or • a compound M3 independently selected from C1-C12 esters of methacrylic acid, C1-C12 esters of acrylic acid, acrylamide, styrene, t-Bu-acrylamide, alkylacrylamides, N-methylolacrylamide, acrylonitrile, vinyl lactam, N-vinylpyrrolidone, ureidomethacrylate, hydroxyethylacrylate, hydroxyethylmethacrylate, hydroxypropylacrylate, hydroxypropylmethacrylate, hydroxybutylmethacrylate, hydroxybutylacrylate, caprolactone methacrylate, caprolactone acrylate, polycaprolactone methacrylate, polycaprolactone acrylate, lactam methacrylate, lactam acrylate, polycaprolactam methacrylate, polycaprolactam acrylate, vinyl acetate and combinations thereof; preferably methacrylic acid C1-C8 esters, acrylic acid C1-C8 esters and combinations thereof; preferably styrene, t-Bu-acrylamide, methylmethacrylate, ethylmethacrylate, propylmethacrylate, butylmethacrylate, methylacrylate, ethyl acrylate, propyl acrylate, butyl acrylate, more preferably, methylmethacrylate, methylacrylate, ethyl acrylate, butylacrylate and combinations thereof.

5. Composition C according to one of claims 1 to 4 for which: the compound T is chosen from sodium hydrogensulfite, potassium hydrogensulfite, calcium di(hydrogensulfite) and combinations thereof; or the initiator compound is chosen from a peroxide (for example hydrogen peroxide, / c / V-butyl hydroperoxide), a persulfate (for example sodium persulfate, ammonium persulfate, potassium persulfate), their combinations and their associations with a metal salt, preferably a metal salt chosen from an iron salt (for example Fe 11 or Fe 111 ), a copper salt (e.g. Cu 1 or Cu 11 ) and their combinations; or compound T is used in an amount of 0.5% by weight to 15% by weight, preferably 1% by weight to 10% by weight, more preferably 1.5% by weight to 8% by weight, relative to the total dry weight amount of monomers used during the polymerization reaction.

6. Composition C according to one of claims 1 to 5 for which: the compound M1 is present during the polymerization reaction in an amount by weight greater than 30%, preferably greater than 35% or 40%, more preferably greater than 45% or 50%, relative to all the compounds present in the reaction medium; or for which: the polymerization reaction comprises: • the preparation of a reaction medium comprising at least one compound Ml in an amount by weight greater than 35%, preferably greater than 50% or 60%, more preferably greater than 65% or 70%, relative to all the reagents in this reaction medium, then • the addition of the initiator compound, of the compound T, and possibly of the compound Ml and • heating the reaction medium.

7. Composition C according to one of claims 1 to 6 comprising: less than 5% by weight, preferably less than 3% by weight or less than 2% by weight, more preferably less than 1.5% by weight or less than 1% by weight, measured by HPLC, of residual monomers, preferably of monomer M1 and optionally of monomers M2 and M3, relative to the quantity of reactants used during the polymerization reaction; or comprising: less than 30% by weight, preferably less than 25% by weight or less than 20% by weight, of oligomers of compound M1 having a molecular mass Mw, measured by CES, of less than 1000 g / mol relative to the quantity of polymer P; or comprising: less than 30% by weight, preferably less than 25% by weight or less than 20% by weight, of oligomers of compound Ml and at least one compound M2 or M3, and having a molecular mass Mw, measured by CES, of less than 1000 g / mol relative to the amount of polymer P.

8. Method for preparing a composition C according to one of claims 1 to 7 comprising: the preparation of a reaction medium comprising at least one compound Ml in an amount by weight greater than 35%, preferably greater than 50% or 60%, more preferably greater than 65% or 70%, relative to all the reactants of the reaction medium, then the addition of the initiator compound, of the compound T, and optionally of the compound Ml and the heating of the reaction medium.

9. Dispersing or grinding agent comprising at least one composition C according to one of claims 1 to 7.

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