Coating pigment composition

Abstract

The present invention relates to a paper coating pigment composition comprising in particular an aqueous rheological agent combining a polyalkoxylated hydrophobic compound and a water-soluble copolymer prepared in the presence of a dialkyl sulfosuccinate derivative. The invention also relates to the use of said composition for producing paper or paperboard and to said aqueous rheological agent capable of effectively controlling the different viscosity components of the coating pigments while improving the water retention of the composition.

Description

[0001] This invention relates to paper coating compositions, particularly comprising an aqueous rheology reagent combining a polyalkoxylated hydrophobic compound and a water-soluble copolymer prepared in the presence of a dialkyl sulfosuccinate derivative. The invention also relates to the use of this composition in the preparation of paper or paperboard, and to an aqueous rheology reagent capable of effectively controlling different viscosity components of paper coating colour while improving its water retention.

[0002] In addition to improving the final properties of papers prepared using these paper-coated pigments, it is also necessary to improve the conditions for preparing and using these paper-coated pigment compositions.

[0003] Furthermore, these compositions must possess a viscosity that allows them to be used effectively under different shear gradients, especially when applied to paper surfaces. Therefore, these compositions must have an apparent viscosity at low shear gradients that is highly suitable for their effective application.

[0004] Furthermore, increased viscosity under both high and low shear gradients affects the migration of water and water-soluble substances within the paper. This migration must be minimized as much as possible, especially by avoiding any changes in the rheological properties of unused paper coating pigments recovered during the coating process. Therefore, it is necessary to properly control the water retention of paper coating pigments.

[0005] In addition, the viscosity of the composition must be controlled to make it easy to pump or filter, especially in the feed loop of the paper coating process.

[0006] Compositions used to prepare paper coating pigments contain insoluble materials, particularly inorganic particles. High concentrations and high solids content in these compositions are generally desirable, although increasing the concentration or solids content increases the risk of viscosity drift, especially under high shear gradients.

[0007] The potential for effective use of very small inorganic particles is also desirable, especially for improving the optical properties of paper. However, these very small inorganic particles can compromise the viscosity and stability of paper coating compositions.

[0008] These compositions must also limit or prevent the settling of the particles used. They must also limit, and even prevent, foaming or splashing.

[0009] The compatibility of different components of the paper coating pigments must also be considered. Of particular importance is ensuring good compatibility with the binding latex used.

[0010] Thickening copolymers and rheological admixtures are commonly used in the preparation of paper coating pigments.

[0011] However, known rheology reagents do not always provide satisfactory solutions to these different problems. Document EP 2776518 describes a paper coating pigment comprising a HASE polymer prepared in the presence of sodium fatty alcohol sulfate and tert-dodecyl mercaptan or n-dodecyl mercaptan. Document EP 3122791 describes an adhesive latex prepared in the presence of dialkyl sulfosuccinate with vinyl acetate, a monomer containing a silane group, and small amounts of acrylic acid and (meth)acrylate. Document EP 2788549 describes a copolymer prepared in the presence of sodium salt of dialkyl sulfosuccinate.

[0012] Therefore, there is a need for improved rheology reagents to provide paper coating compositions.

[0013] The water-based paper coating composition according to the present invention provides a solution to all or some of the problems of compositions in the prior art. Therefore, the present invention provides a water-based paper coating composition C, comprising:

[0014] - At least one aqueous rheological reagent R, comprising:

[0015] • At least one water-soluble copolymer P, prepared by polymerization of the following substances in the presence of at least one compound E, wherein compound E is selected from dialkyl sulfosuccinates, sodium dialkyl sulfosuccinates, and combinations thereof:

[0016] o At least one compound selected from methacrylic acid, methacrylates, methacrylic acid oligomers, methacrylic acid oligomer salts, acrylic acid, acrylates, acrylic acid oligomers, acrylic acid oligomer salts, salts thereof, and combinations thereof (a);

[0017] o At least one selected from C1-C 10 -Alkyl methacrylate, C1-C 10 - Alkyl acrylates, styrene, vinyl caprolactam, vinyl acetate and combinations thereof (b);

[0018] • At least one compound F of formula I:

[0019] R-(OE) x -OH (I)

[0020] Where R represents the straight chain C6-C 40 -alkyl or branched C6-C 40-alkyl, OE represents oxyethylidene, and x represents a number from 1 to 50;

[0021] - Particles of at least one mineral material M;

[0022] - at least one adhesive L; and

[0023] -water.

[0024] Preferably, according to the invention, composition C comprises polymer P prepared in the presence of compound E, said compound E being selected from dioctyl sulfosuccinate, sodium dioctyl sulfosuccinate, and combinations thereof, said compound E optionally being combined with at least one thiol compound. Preferably, according to the invention, the thiol compound comprises a straight-chain C8-C... 16 -alkyl or branched C8-C 16 -alkyl group, more preferably, the thiol compound is selected from tert-nonylthiol, tert-dodecylthiol, n-dodecylthiol, and combinations thereof. More preferably, compound E is tert-nonylthiol.

[0025] According to the present invention, polymer P is preferably water-soluble at a pH greater than 5, and more preferably at a pH greater than 6.

[0026] Preferably, according to the present invention, the molecular weight Mw of polymer P, as measured by CES, is 20,000 g / mol to 800,000 g / mol or 20,000 g / mol to 500,000 g / mol, more preferably 20,000 g / mol to 400,000 g / mol or 20,000 g / mol to 300,000 g / mol.

[0027] According to the present invention, the molecular weight Mw is determined by size exclusion chromatography (CES) or gel permeation chromatography (GPC). This technique uses a Waters liquid chromatograph equipped with a detector. The detector is a Waters refractive index detector. The liquid chromatograph is equipped with a size exclusion column to separate the various molecular weights of the copolymer under study. The liquid eluent is an aqueous phase adjusted to pH 9.00 using 1N sodium hydroxide, containing 0.05M NaHCO3, 0.1M NaNO3, 0.02M triethanolamine, and 0.03% NaN3.

[0028] According to the first step, the copolymer solution was diluted to 0.9% dry weight in the CES dissolving solvent. This corresponds to the addition of 0.04% dimethylformamide to the liquid eluent phase of CES, which serves as a flow label or internal standard. The solution was then filtered using a 0.2µm filter. 100µL was then injected into the chromatograph (eluent: an aqueous phase adjusted to pH 9.00 with 1N sodium hydroxide, containing 0.05M NaHCO3, 0.1M NaNO3, 0.02M triethanolamine, and 0.03% NaN3).

[0029] The liquid chromatograph features an isocratic pump (“Waters” 515) with a flow rate set to 0.8 mL / min. The chromatograph also includes an oven containing the following column system in series: a 6 cm long, 40 mm inner diameter “Waters Ultrahydrogel Guard” pre-column and a 30 cm long, 7.8 mm inner diameter “Waters Ultrahydrogel” linear column. The detection system consists of a “Waters RI” 410 refractometric detector. The oven is heated to 60°C, and the refractometer is heated to 45°C. The chromatograph is calibrated using supplier-certified sodium polyacrylate powder standards of varying molecular weights: Polymer Standards Service or American Polymers Standards Corporation (molecular weights from 900 g / mol to 2,250,000 g / mol, polymolecularity index from 1.4 to 1.7).

[0030] Preferably, according to the invention, polymer P is completely acidic or partially acidic, or completely neutralized or partially neutralized. More preferably, polymer P is partially neutralized, preferably using at least one compound selected from LiOH, NaOH, KOH, Zn(OH)2, Mg(OH)2, Ca(OH)2, ZnO, MgO, CaO, ammonium derivatives, ammonia, ammonia, amino bases, such as triethanolamine, aminomethylpropanol, or 2-amino-2-methyl-1-propanol AMP and combinations thereof to neutralize polymer P. More preferably, LiOH, NaOH, KOH, Mg(OH)2, Ca(OH)2, ammonia, and combinations thereof are used to neutralize polymer P.

[0031] Basically, according to the present invention, polymer P is prepared by polymerization of at least one monomer (a) and at least one monomer (b) in the presence of at least one compound E.

[0032] Preferably, according to the invention, monomer (a) is methacrylic acid alone or methacrylic acid in combination with acrylic acid. More preferably, when acrylic acid is used, the amount of acrylic acid by mass is less than the amount of methacrylic acid by mass.

[0033] Also preferably, according to the invention, monomer (b) is selected from C1-C4-alkyl acrylates, C1-C4-alkyl methacrylates, and combinations thereof. More preferably, monomer (b) is selected from methyl acrylate, ethyl acrylate, propyl acrylate, isobutyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, aryl acrylates, particularly phenyl acrylate, benzyl acrylate, phenoxyethyl acrylate, aryl methacrylates, especially phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, and combinations thereof. Even more preferably, it is selected from methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, and methyl methacrylate, and even more preferably from methyl acrylate and ethyl acrylate.

[0034] In addition to monomers (a) and (b), polymer P can also be prepared using one or more other monomers. Therefore, preferably, according to the invention, copolymer P can be prepared by a polymerization reaction that also uses at least one compound (c) of formula II:

[0035] R 1 -(OE) m -(OP) n -R 2 (II)

[0036] in:

[0037] -m or n is different from 0;

[0038] -m independently represents 0 or a number less than 150;

[0039] -n independently represents 0 or a number less than 150;

[0040] -OE indicates oxyethylidene;

[0041] -OP independently represents an oxopropylene group;

[0042] -R 1The group represents a group containing at least one polymerizable olefinic unsaturation bond, preferably a group selected from acrylate, methacrylate, acryl urethane, methacryl urethane, vinyl, allyl, methacryl and isoprene, and more preferably a methacrylate group.

[0043] -R 2 It refers to a straight-chain, branched, or cyclic saturated, unsaturated, or aromatic hydrocarbon group containing 6 to 40 carbon atoms, preferably a straight-chain or branched C6-C group. 40 Alkyl groups, preferably straight-chain or branched C8-C. 30 Alkyl, C6-C 40 Aryl, preferably C8-C 30 Aryl groups, such as tristyrylphenyl.

[0044] Preferably, according to the present invention, compound (c) is a compound of formula II, wherein:

[0045] -m represents an integer or decimal between 20 and 40, where n is zero, or

[0046] -m and n independently represent integers or decimals from 5 to 100, or

[0047] - The mass ratio m / n is 90 / 10 to 70 / 30.

[0048] More preferably, according to the present invention, compound (c) is a compound of formula II, wherein:

[0049] -m independently represents numbers from 2 to 50;

[0050] -n independently represents 0;

[0051] -OE indicates oxyethylidene;

[0052] -R 1 The group represents a group containing at least one polymerizable olefinic unsaturated bond, preferably a group selected from acrylate, methacrylate, vinyl, allyl, methalyl and isoprene; more preferably a methacrylate group.

[0053] -R 2 This refers to a straight-chain, branched, or cyclic, saturated, unsaturated, or aromatic hydrocarbon group, wherein the hydrocarbon group comprises 6 to 40 carbon atoms, preferably straight-chain or branched C6-C. 40 Alkyl groups, preferably straight-chain or branched C8-C. 30 Alkyl, C6-C40 Aryl, preferably C8-C 30 Aryl groups, such as tristyrylphenyl.

[0054] According to the present invention, the polymerization reaction may also use at least one compound (d) selected from:

[0055] - Polyalkylene glycol acrylate, preferably selected from polyethylene glycol acrylate and polyethylene-polypropylene glycol acrylate.

[0056] - Polyalkylene glycol methacrylate, preferably selected from polyethylene glycol methacrylate and polyethylene-polypropylene glycol methacrylate.

[0057] - Allyl polyalkylene glycol, preferably selected from allyl polyethylene glycol and allyl polyethylene-polypropylene glycol.

[0058] -Methylallyl polyalkylene glycol, preferably selected from methylallyl polyethylene glycol and methylallyl polyethylene-polypropylene glycol.

[0059] -3-methyl-3-buten-1-yl polyalkylene glycol, preferably selected from 3-methyl-3-buten-1-yl polyethylene glycol and 3-methyl-3-buten-1-yl polyethylene-polypropylene glycol.

[0060] According to the invention, the polymerization reaction may also use at least one crosslinking compound (e) or at least one compound (e) containing at least two olefinic unsaturations. However, preferably, according to the invention, the polymerization reaction does not use any compound (e).

[0061] According to the present invention, the polymerization reaction may also use at least one compound selected from 2-acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl methacrylate, sodium methylallyl sulfonate, styrene sulfonate, their salts, and combinations thereof. However, preferably, according to the present invention, the polymerization reaction does not use any compound selected from 2-acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl methacrylate, sodium methylallyl sulfonate, styrene sulfonate, and their salts.

[0062] The proportions of different monomers used to prepare copolymer P can vary considerably. Preferably, copolymer P comprises, relative to the total mass of monomers,:

[0063] -20% to 50% by mass monomers (a) and 50% to 80% by mass monomers (b); or

[0064] Monomers ranging from -35% to 44.9% by mass (a), monomers ranging from 55% to 74.9% by mass (b), and monomers ranging from 0.1% to 10% by mass (c); or

[0065] Monomers ranging from -40% to 44.9% by mass (a), monomers ranging from 55% to 74.9% by mass (b), and monomers ranging from 0.1% to 5% by mass (d); or

[0066] Monomers ranging from -40% to 44.9% by mass (a), monomers ranging from 55% to 74.9% by mass (b), and monomers ranging from 0.1% to 5% by mass (e); or

[0067] Monomers ranging from -30% to 44.8% by mass (a), monomers ranging from 55% to 74.8% by mass (b), monomers ranging from 0.1% to 10% by mass (c), and monomers ranging from 0.1% to 5% by mass (d); or

[0068] Monomers ranging from -30% to 44.8% by mass (a), monomers ranging from 55% to 74.8% by mass (b), monomers ranging from 0.1% to 10% by mass (c), and monomers ranging from 0.1% to 5% by mass (e); or

[0069] Monomers ranging from -35% to 44.8% by mass (a), monomers ranging from 55% to 74.8% by mass (b), monomers ranging from 0.1% to 5% by mass (d), and monomers ranging from 0.1% to 5% by mass (e); or

[0070] Monomers ranging from -25% to 44.7% by mass (a), monomers ranging from 55% to 74.7% by mass (b), monomers ranging from 0.1% to 10% by mass (c), monomers ranging from 0.1% to 5% by mass (d) and monomers ranging from 0.1% to 5% by mass (e).

[0071] Basically, according to the present invention, the rheology reagent R comprises at least one compound F of formula I. Preferably, according to the present invention, compound F is a compound of formula I, wherein R represents a straight-chain C6-C... 40 -alkyl, preferably straight-chain C 12 -C 24 -alkyl.

[0072] Also preferably, according to the invention, compound F is a compound of formula I, wherein x represents a number from 1 to 30, preferably a number from 5 to 25. More preferably, according to the invention, R represents a straight-chain C6-C 40 -alkyl, preferably straight-chain C 12 -C 24 -alkyl, and x represents a number from 1 to 30.

[0073] More preferably, according to the invention, compound F is a compound of formula I, wherein x represents a number from 1 to 30, preferably a number from 5 to 25. More preferably, according to the invention, R represents a straight-chain C6-C 40 -alkyl, preferably straight-chain C 12 -C 24 -alkyl, and x represents a number from 5 to 25.

[0074] In addition to water, the rheology reagent R according to the invention also comprises a water-soluble copolymer P and a compound F of formula I. The amounts of these compounds can vary. Preferably, for the composition C according to the invention, the aqueous rheology reagent R comprises 0.05% to 5% dry mass of compound F, more preferably 0.1% to 2% dry mass of compound F, relative to the amount of copolymer P on a dry mass basis.

[0075] In addition to water, the aqueous composition C according to the invention also comprises an aqueous rheology reagent R, particles of at least one mineral material M, and a binder L. The amounts of these components can vary. Preferably, according to the invention, the composition according to the invention comprises, relative to the mass of the composition:

[0076] -0.02% to 2% (dry mass) of aqueous rheology reagent R;

[0077] -30% to 90% dry mass of mineral material M particles;

[0078] -2% to 25% dry mass of adhesive L; and

[0079] -7.98% by mass to 44.98% by mass of water.

[0080] Basically, the composition C according to the invention comprises mineral material M in particulate form. Preferably, according to the invention, the particles of mineral material M have a size of less than 50 µm or a size of 0.05 µm to 50 µm or less than 10 µm, preferably less than 5 µm or 2 µm, more preferably less than 1 µm or less than 0.5 µm.

[0081] Also preferably, according to the invention, for particles of mineral material M with a size of 0.05µm to 50µm or less than 50µm, preferably for particles with a size of less than 10µm, more preferably less than 5µm or 2µm, and even more preferably less than 1µm or less than 0.5µm, the equivalent spherical diameter is equal to 60% by weight or equal to 70% by weight.

[0082] More preferably, according to the present invention, for particles of mineral material M with a size of 0.05µm to 50µm or less than 50µm, preferably less than 10µm, more preferably less than 5µm or 2µm, and even more preferably less than 1µm or less than 0.5µm, the equivalent sphere diameter is equal to 80% by weight or even equal to 90% by weight.

[0083] According to the present invention, composition C may contain a single mineral material M or two or three mineral materials M. Preferably, composition C contains a single mineral material M.

[0084] Preferably, according to the present invention, the mineral material M is synthetic or of natural origin. More preferably, the mineral material M is selected from alkaline earth metal carbonates, preferably calcium carbonate (natural calcium carbonate or precipitated calcium carbonate), strontium carbonate, magnesium carbonate, barium carbonate, dolomite, kaolin, titanium dioxide, talc, lime, calcium sulfate, barium sulfate, and silicon dioxide. More preferably, material M is calcium carbonate (natural calcium carbonate or precipitated calcium carbonate) or kaolin.

[0085] Preferably, according to the present invention, the adhesive L is a natural adhesive, such as starch, carboxymethyl cellulose (CMC), hydroxyethyl cellulose, polyvinyl alcohol (PVOH), casein, protein, alginate, or a synthetic adhesive, such as latex. More preferably, the adhesive L is selected from styrene-butadiene polymers, styrene-acrylic acid polymers, styrene-acetic acid polymers, and even more preferably styrene-butadiene polymers.

[0086] In addition to the aqueous rheology reagent R, the mineral material particles M, and the binder L, the composition C according to the invention may also contain at least one admixture, particularly at least one admixture selected from dispersants, defoamers, antimicrobial agents, colorants, lubricants, and optical brighteners.

[0087] The composition C according to the invention has several advantageous properties. These properties are particularly effective in the preparation of paper or paperboard. Therefore, the invention also provides a method for preparing paper or paperboard, comprising using the aqueous composition C according to the invention. Preferably, the composition C is used in one or more paper or paperboard coating steps.

[0088] The paper coating pigment prepared according to the present invention is particularly advantageous when preparing a primary coating (pre-coating), a final paper coating (top coat), or even a simple coat.

[0089] Furthermore, when a method for preparing paper or paperboard using the aqueous composition according to the invention is employed, the water retention of the composition is improved during the paper coating step. Preferably, according to the invention, the water retention of composition C, measured according to the method used in the examples, is increased by 50% to 400% by volume relative to the absence of copolymer P during the paper coating step.

[0090] Similarly, when using a method for preparing paper or paperboard that includes the use of an aqueous composition C according to the invention, the viscosity of the composition is controlled by the properties of the copolymer P. Preferably, the method according to the invention includes using composition C according to the invention, which has a Brookfield viscosity measured at 100 rpm and 25°C according to the method used in the examples, a viscosity that is sufficient and compatible for the coating process, and a viscosity greater than that of a composition without copolymer P.

[0091] More preferably, according to the present invention, the Brinell viscosity of composition C, measured at 100 rpm and 25°C according to the method used in the examples, is from 150 mPa·s to 3500 mPa·s, more preferably from 500 mPa·s to 2000 mPa·s.

[0092] Similarly, more preferably, according to the invention, the method used in the examples is applied for 1,000,000 seconds. -1 The capillary viscosity of composition C, measured at 25°C, is from 10 mPa·s to 100 mPa·s, more preferably from 20 mPa·s to 80 mPa·s.

[0093] Also preferably, when paper or paperboard is prepared using composition C according to the invention, composition C is deposited on the surface of the paper or paperboard in at least one coating step, and the dried coating weight, measured according to the method used in the examples, is 5 g / m². 2 Up to 50g / m 2 More preferably 8g / m 2Up to 40g / m 2 .

[0094] The coating weight can be applied using a blade or creaming, film transfer press, air knife, size press, or curtain coating method.

[0095] Basically, according to the present invention, the aqueous paper coating composition C comprises an aqueous rheology reagent R, which imparts to it many desirable properties for the preparation of paper or paperboard, particularly for controlling its viscosity, and especially its viscosity under high shear gradients. Therefore, the present invention provides a method for controlling the high-gradient viscosity of the aqueous paper coating composition C, wherein the viscosity, according to the method used in the examples, is within 1,000,000 s. -1 As measured at 25°C, the aqueous paper coating composition C comprises particles of at least one mineral material M, at least one binder L, and water. The method includes adding at least one aqueous rheology reagent R to the composition, which comprises:

[0096] - At least one water-soluble copolymer P, prepared by polymerization of the following substances in the presence of at least one compound E, wherein compound E is selected from dialkyl sulfosuccinates, sodium dialkyl sulfosuccinates, and combinations thereof:

[0097] • At least one compound (a) selected from methacrylic acid, methacrylates, methacrylate oligomers, methacrylate oligomer salts, acrylic acid, acrylates, acrylic acid oligomers, acrylic acid oligomer salts, and combinations thereof;

[0098] • At least one compound (b), selected from C1-C 10 -Alkyl methacrylate, C1-C 10 - Alkyl acrylates, styrene, vinyl caprolactam, vinyl acetate and combinations thereof (b);

[0099] - At least one compound F of formula I:

[0100] R-(OE) x -OH (I)

[0101] Where R represents the straight chain C6-C 40 -alkyl or branched C6-C 40 -alkyl, OE represents oxyethylidene, x represents a number from 1 to 50.

[0102] Basically, according to the present invention, reagent R combines copolymer P and compound F. According to the present invention, reagent R can be prepared prior to its introduction into the aqueous composition, preferably introduced into the aqueous paper coating composition. According to the present invention, reagent R can also be prepared ad hoc when introducing copolymer P and compound F into the aqueous composition, preferably introduced into the aqueous paper coating composition.

[0103] Therefore, the present invention also provides an aqueous rheological reagent R, which combines:

[0104] - At least one water-soluble copolymer P, prepared by polymerization of the following substances in the presence of at least one compound E, wherein compound E is selected from dialkyl sulfosuccinates, sodium dialkyl sulfosuccinates, and combinations thereof:

[0105] • At least one compound selected from methacrylic acid, methacrylates, methacrylic acid oligomers, methacrylic acid oligomer salts, acrylic acid, acrylates, acrylic acid oligomers, acrylic acid oligomer salts, and combinations thereof (a);

[0106] • At least one of the following is selected from C1-C 10 -Alkyl methacrylate, C1-C 10 - Alkyl acrylates, styrene, vinyl caprolactam, vinyl acetate and combinations thereof (b);

[0107] - At least one compound F of formula I:

[0108] R-(OE) x -OH (I)

[0109] Where R represents the straight chain C6-C 40 -alkyl or branched C6-C 40 -alkyl, OE represents oxyethylidene, x represents a number from 1 to 50.

[0110] According to the present invention, reagent R can be prepared in advance. Therefore, the present invention also provides an aqueous rheology reagent R, which comprises:

[0111] - At least one water-soluble copolymer P, prepared by polymerization in the presence of at least one compound E, said compound E being selected from dialkyl sulfosuccinates, sodium dialkyl sulfosuccinates, and combinations thereof:

[0112] • At least one compound selected from methacrylic acid, methacrylates, methacrylic acid oligomers, methacrylic acid oligomer salts, acrylic acid, acrylates, acrylic acid oligomers, acrylic acid oligomer salts, and combinations thereof (a);

[0113] • At least one of the following is selected from C1-C 10 -Alkyl methacrylate, C1-C10 - Alkyl acrylates, styrene, vinyl caprolactam, vinyl acetate and combinations thereof (b);

[0114] - At least one compound F of formula I:

[0115] R-(OE) x -OH (I)

[0116] Where R represents the straight chain C6-C 40 -alkyl or branched C6-C 40 -alkyl, OE represents oxyethylidene, x represents a number from 1 to 50.

[0117] Preferably, according to the present invention, the aqueous rheology reagent R comprises polymer P and compound F as defined in the present invention.

[0118] The specific, advantageous, or preferred features of composition C according to the invention define the specific, advantageous, or preferred methods and reagents R according to the invention.

[0119] The following examples illustrate various aspects of the present invention, particularly the preparation and characterization of the paper coating compositions according to the present invention. Example

[0120] Polymers P1 and P2 according to the present invention, and rheological reagents R1 and R2 according to the present invention Preparation:

[0121] Use the following compounds:

[0122] - Compound (a), AMA: methacrylic acid,

[0123] - Compound (b), EA: Ethyl acrylate,

[0124] - Compound E, DOS: 50% aqueous solution of dioctyl sulfosuccinate.

[0125] - tert-nonylthiol,

[0126] - Ammonium persulfate, (NH4)2S2O8,

[0127] - Sodium metabisulfite, Na2S2O5,

[0128] - Compound F1, Genapol T200 (Clariant): 20-ethoxylated C-C 16 -C 18 -alkyl alcohols,

[0129] - Compound F2, Genapol UD088 (Clariant): Oxy-C oxidized 8 times. 11 -Alkyl alcohol.

[0130] Mixture 1 was prepared in a stirred 1L reactor heated in an oil bath by introducing deionized water and a dioctyl sulfosuccinate solution. Mixture 2, containing monomers in deionized water, was prepared in a beaker under stirring.

[0131] - Monomer (a), AMA,

[0132] - Monomer (b), EA,

[0133] - A 50% aqueous solution of dioctyl sulfosuccinate

[0134] - Transfer agent, tert-nonylthiol.

[0135] An initiator solution comprising ammonium persulfate, deionized water, and sodium metabisulfite was prepared. The reactor was heated to 76±1℃, and then the initiator solution was injected together with mixture 2 for 2 hours. The mixture was then heated at 80±1℃ for 1 hour. The batch was then cooled to room temperature. Finally, compound F was added. The reagents and amounts used, as well as the properties of polymers P1 and P2, and reagents R1 and R2, are shown in Table 1.

[0136]

[0137] Table 1

[0138] Preparation and characterization of compositions C1, C2 and C3 according to the present invention:

[0139] pH values ​​were measured using a pH meter (WTW) at 25°C. The pH meter had conventional electrodes that were connected to a temperature probe.

[0140] The dry solids content was measured using a microwave balance (CEM). A portion of the composition, estimated to weigh between 1 g and 4 g, was coated onto a piece of sandpaper. It was then dried in the microwave balance. The balance was stopped when the weight no longer changed within 10 seconds. The weight difference, expressed as a percentage, was used to determine the solids content.

[0141] The Brinell viscosity of the prepared composition was measured using a simulated viscometer at 100 rpm and 25°C. The spindle was selected based on the viscosity of the composition under study to ensure it was within the optimal range of the rheometer.

[0142] Using a capillary viscometer (ACAV A2 ACA) at 25°C and 10... 6 s -1 The capillary viscosity was measured.

[0143] Water retention was assessed at 25°C using a retenometer (AAGWR Gradek), which includes a measuring chamber in which test paper (Test Blotter Paper Gradek) is placed, covered with a perforated plastic sheet (Test Filter PCTE Gradek - 2µm). 10 mL of the composition was then added to the chamber. The AAGWR device allows pressure (1.5 bar) to be applied to the composition, causing all or part of the water and water-soluble substances in the composition to pass through the perforated plastic sheet and migrate into the test paper. The pressure of 1.5 bar was applied for 90 seconds. The difference between the weight of the test paper before measurement (P0) and the weight after measurement (P1) gives the amount of water and water-soluble substances in the composition that migrated into the test paper during the measurement. The relative increase in water retention is 1250 × (P1 - P0) / P0.

[0144] Mix 90 parts by weight of material M granules (“Hydrocarb 95” calcium carbonate, “Omya”), 10 parts by weight of second material M granules (“Capim DG” kaolin, “Imerys”), 0.15 parts of dispersant (“Topseperse GXN” sodium polyacrylate, “COATEX”), 10 parts of binder L (DL 1066 styrene-butadiene latex, “Trinseo”), and 0.5 parts of optical brightener (“Blankophor 4900”) under stirring.

[0145] The mixture has a solids content of 67%, a pH of 9, and a capillary viscosity of 1,000,000 s. -1 The measured value was 60 mPa·s.

[0146] Composition C1 according to the invention was obtained by adding C and 0.2 parts by mass of reagent R1 to the mixture using a "VMI Turbotest" engine under stirring. The properties of composition C1 according to the invention were measured:

[0147] Brinell viscosity at -100 rpm: 1000 mPa·s

[0148] -Water retention: 210g / m³ 2 ,

[0149] - Capillary viscosity: 65 mPa.s.

[0150] Similarly, composition C2 according to the invention, prepared using 0.2 parts by mass of reagent R2, was prepared and characterized as follows:

[0151] Brinell viscosity at -100 rpm: 1000 mPa·s

[0152] -Water retention: 185g / m³ 2 ,

[0153] - Capillary viscosity: 65 mPa.s.

[0154] Similarly, composition C3 according to the invention, prepared using 0.2 parts by weight of reagent R3, was prepared and characterized as follows:

[0155] Brinell viscosity at -100 rpm: 950 mPa·s

[0156] -Water retention: 210g / m³ 2 ,

[0157] - Capillary viscosity: 70 mPa.s.

[0158] According to the present invention, reagents R1, R2 and R3 combine compound F1 or compound F2 with polymers P1, P2 and P3 respectively, so that an aqueous paper coating composition C having a Brinell viscosity that makes it easy to use in papermaking can be prepared.

[0159] Reagents R1, R2 and R3 are particularly effective in limiting the capillary viscosity of the water-containing paper coating composition C and improving its water retention.

Claims

1. An aqueous paper coating composition C comprising: - at least one aqueous rheology agent R comprising: • at least one water-soluble copolymer P prepared by a polymerization reaction of the following substances in the presence of at least one compound E selected from the group consisting of dialkyl sulfosuccinates, sodium dialkyl sulfosuccinates, and combinations thereof: o at least one compound (a) selected from the group consisting of methacrylic acid, methacrylic acid salts, methacrylic acid oligomers, methacrylic acid oligomer salts, acrylic acid, acrylic acid salts, acrylic acid oligomers, acrylic acid oligomer salts, salts thereof, and combinations thereof; o at least one compound (b) selected from the group consisting of C1-C 10 - alkyl methacrylates, C1-C 10 - alkyl acrylates, styrene, vinyl caprolactam, vinyl acetate and combinations thereof; • at least one compound F of formula I: R-(OE) x -OH (I) in which R represents a linear C6-Ci8alkyl group 40 - an alkyl group or a branched C6-Ci8alkyl group 40 - an alkyl group, OE represents an oxyethylene group, and x represents a number from 1 to 50; - particles of at least one mineral material M; - at least one binder L; and - water.

2. The composition according to claim 1, wherein: - said polymer P is prepared in the presence of a compound E selected from the group consisting of dioctyl sulfosuccinate, sodium dioctyl sulfosuccinate, and combinations thereof, said compound E being optionally combined with at least one thiol compound, preferably said thiol compound comprises a linear C8-C 16 - alkyl or branched C8-C 16 - alkyl, more preferably said thiol compound is selected from the group consisting of tertiary-nonyl mercaptan, tertiary-dodecyl mercaptan, n-dodecyl mercaptan, and combinations thereof; or - the polymer P is water-soluble at a pH greater than 5, preferably at a pH greater than 6; or - the molecular weight Mw of the polymer P is measured by CES to be between 20,000 g / mol and 800,000 g / mol or between 20,000 g / mol and 500,000 g / mol, preferably between 20,000 g / mol and 400,000 g / mol or between 20,000 g / mol and 300,000 g / mol; or - the polymer P is fully acidic or partially acidic or fully neutralized or partially neutralized; preferably the polymer P is partially neutralized, preferably neutralized using at least one compound selected from the group consisting of LiOH, NaOH, KOH, Zn(OH)2, Mg(OH)2, Ca(OH)2, ZnO, MgO, CaO, ammonium derivatives, aqueous ammonia, ammonia, amino bases such as triethanolamine, aminomethyl propanol or 2-amino-2-methyl-1-propanol (AMP), and combinations thereof, more preferably using at least one compound selected from the group consisting of LiOH, NaOH, KOH, Mg(OH)2, Ca(OH)2, ammonia, and combinations thereof.

3. The composition according to any one of claims 1 or 2, wherein: - monomer (a) is methacrylic acid alone or methacrylic acid in combination with acrylic acid, preferably the amount by mass of acrylic acid is less than the amount by mass of methacrylic acid; or - monomer (b) is selected from the group consisting of C1-C4-alkyl acrylates, C1-C4-alkyl methacrylates, and combinations thereof; preferably selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, isobutyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, aryl acrylates, in particular phenyl acrylate, benzyl acrylate, phenoxyethyl acrylate, aryl methacrylates, in particular phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, and combinations thereof; more preferably selected from the group consisting of methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, methyl methacrylate, still more preferably selected from the group consisting of methyl acrylate and ethyl acrylate.

4. The composition according to any one of claims 1 to 3, wherein the copolymer P is prepared by a polymerization reaction which further uses: • at least one compound (c) of formula II: R 1 -(OE) m (OP) n -R 2 (II) in which: - m or n is different from 0; - m independently represents 0 or a number lower than 150; - n independently represents 0 or a number lower than 150; - OE represents oxyethylene; - OP independently represents oxypropylene; - R 1 represents a group comprising at least one polymerizable olefinic unsaturation, preferably a group selected from acrylate, methacrylate, acryloyl carbamate, methacryloyl carbamate, vinyl, allyl, methallyl and isoprenyl, more preferably a methacrylate group; - R 2 represents a linear, branched or cyclic saturated, unsaturated or aromatic hydrocarbon group comprising 6 to 40 carbon atoms, preferably a linear or branched C6-C 40 alkyl, preferably a linear or branched C8-C 30 alkyl, C6-C 40 aryl, preferably a C8-C 30 aryl, for example a triphenyl ethylene phenyl; Preferably, the compound (c) is a compound of formula II in which: - m represents an integer or a decimal number from 20 to 40 and n is zero, or - m and n independently represent an integer or a decimal number from 5 to 100, or - the mass ratio m / n is from 90 / 10 to 70 / 30; or • at least one compound (d) selected from: - polyalkylene glycol acrylates, preferably selected from polyethylene glycol acrylates and polyethylene-polypropylene glycol acrylates, - polyalkylene glycol methacrylates, preferably selected from polyethylene glycol methacrylates and polyethylene-polypropylene glycol methacrylates, - allyl polyalkylene glycols, preferably selected from allyl polyethylene glycols and allyl polyethylene-polypropylene glycols, - methallyl polyalkylene glycols, preferably selected from methallyl polyethylene glycols and methallyl polyethylene-polypropylene glycols, - 3-methyl-3-buten-1-yl polyalkylene glycols, preferably selected from 3-methyl-3-buten-1-yl polyethylene glycols or 3-methyl-3-buten-1-yl polyethylene-polypropylene glycols; or • at least one crosslinking compound (e) or at least one compound (e) comprising at least two ethylenically unsaturated bonds.

5. The composition according to any one of claims 1 to 4, wherein, The copolymer P comprises, relative to the total amount of monomers by mass: - 20% to 50% by mass of monomers (a) and 50% to 80% by mass of monomers (b); or - 35% to 44.9% by mass of monomers (a), 55% to 74.9% by mass of monomers (b) and 0.1% to 10% by mass of monomers (c); or - 40% to 44.9% by mass of monomers (a), 55% to 74.9% by mass of monomers (b) and 0.1% to 5% by mass of monomers (d); or - 40% to 44.9% by mass of monomers (a), 55% to 74.9% by mass of monomers (b) and 0.1% to 5% by mass of monomers (e); or - 30% to 44.8% by mass of monomers (a), 55% to 74.8% by mass of monomers (b), 0.1% to 10% by mass of monomers (c) and 0.1% to 5% by mass of monomers (d); or - 30% to 44.8% by mass of monomers (a), 55% to 74.8% by mass of monomers (b), 0.1% to 10% by mass of monomers (c) and 0.1% to 5% by mass of monomers (e); or - 35 to 44.8 mass% of monomer (a), 55 to 74.8 mass% of monomer (b), 0.1 to 5 mass% of monomer (d) and 0.1 to 5 mass% of monomer (e); or - 25 to 44.7 mass% of monomer (a), 55 to 74.7 mass% of monomer (b), 0.1 to 10 mass% of monomer (c), 0.1 to 5 mass% of monomer (d) and 0.1 to 5 mass% of monomer (e).

6. The composition according to any one of claims 1 to 5, wherein compound F is a compound of formula I, wherein R represents a linear C6-C 40 - alkyl, preferably linear C 12 - C 24 - alkyl; or wherein x represents a number from 1 to 30, preferably a number from 5 to 25; preferably R represents a linear C6-C 40 - alkyl, preferably linear C 12 - C 24 - alkyl, and x represents a number from 1 to 30, preferably a number from 5 to 25.

7. The composition according to any one of claims 1 to 6, comprising, relative to the amount by mass of the composition: - 0.02 to 2 dry mass% of the aqueous rheology agent R; - 30 to 90 dry mass% of particles of mineral material M; - 2 to 25 dry mass% of binder L; and - 7.98 to 44.98 mass% of water; or wherein: The aqueous rheology agent R comprises, relative to the amount by dry mass of the copolymer P, 0.05 to 5 dry mass%, preferably 0.1 to 2 dry mass% of the compound F.

8. The composition according to any one of claims 1 to 7, wherein: - the particles of mineral material M have a size of less than 50 pm or a size of 0.05 pm to 50 pm or a size of less than 10 pm, preferably less than 5 pm or 2 pm, more preferably less than 1 pm or less than 0.5 pm; or wherein: - for particles of mineral material M having a size of 0.05 pm to 50 pm or less than 50 pm, preferably less than 10 pm, more preferably less than 5 pm or 2 pm, even more preferably less than 1 pm or less than 0.5 pm, the equivalent sphere diameter is equal to 60 wt% or equal to 70 wt% or even equal to 80 wt% or even equal to 90 wt%; or comprises: - a single mineral material M is used or two or three mineral materials M are used; or wherein: - the mineral material M is of synthetic origin or of natural origin, preferably selected from alkaline earth carbonates, preferably calcium carbonate (natural calcium carbonate or precipitated calcium carbonate), strontium carbonate, magnesium carbonate, barium carbonate, dolomite, kaolin, titanium dioxide, talc, lime, calcium sulfate, barium sulfate, silicon dioxide, more preferably calcium carbonate (natural calcium carbonate or precipitated calcium carbonate) or kaolin; or wherein: - the binder L is a natural binder, such as starch, carboxymethylcellulose (CMC), hydroxyethylcellulose, polyvinyl alcohol (PVOH), casein, proteins, alginates, or a synthetic binder, such as a latex, preferably selected from styrene-butadiene polymers, styrene-acrylic acid polymers, styrene-acetate polymers, more preferably styrene-butadiene polymers; or the composition further comprises - at least one additional agent, in particular at least one additional agent selected from dispersing agents, defoamers, antimicrobial agents, colorants, lubricants and optical brighteners.

9. A method of making paper or paperboard comprising the use of an aqueous composition C according to any one of claims 1 to 8; preferably the composition C is used in one or more paper or paperboard coating steps.

10. The method according to claim 9, wherein: - the water retention of the composition C measured according to the method in the description is improved during the paper coating step; preferably the water retention of the composition C is improved by 50% to 400% by volume with respect to a composition not using the copolymer P; or wherein: - the Brookfield viscosity of the composition C measured according to the method in the description at 100 rpm and 25°C is sufficient and compatible for the coating process and the measured viscosity is higher than the viscosity of a composition not containing the copolymer P; preferably: - the Brookfield viscosity of the composition C measured according to the method in the description at 100 rpm and 25°C is from 150 mPa.s to 3500 mPa.s, more preferably from 500 mPa.s to 2000 mPa.s; or wherein: - Follow the instructions for 1,000,000 seconds -1 The capillary viscosity of composition C, measured at 25°C, is from 10 mPa·s to 100 mPa·s, more preferably from 20 mPa·s to 80 mPa·s; or wherein: - the composition C is deposited on the surface of the paper or paperboard in at least one coating step, the deposit measured after drying being between 5 g / m 2 and 50 g / m 2 , preferably between 8 g / m 2 and 40 g / m 2 .

11. A method for controlling the high gradient viscosity of an aqueous paper coating composition C, wherein the high gradient viscosity is within 1,000,000 s according to the method described in the specification. -1 As measured at 25°C, the aqueous paper coating composition C comprises particles of at least one mineral material M, at least one binder L, and water. The method includes adding at least one aqueous rheology reagent R to the composition, the aqueous rheology reagent R comprising: - at least one water-soluble copolymer P prepared by polymerization reaction of the following substances in the presence of at least one compound E selected from the group consisting of dialkyl sulfosuccinates, dialkyl sulfosuccinate sodium salts and combinations thereof: • at least one compound (a) selected from the group consisting of methacrylic acid, methacrylic acid salts, methacrylic acid oligomers, methacrylic acid oligomer salts, acrylic acid, acrylic acid salts, acrylic acid oligomers, acrylic acid oligomer salts and combinations thereof; • at least one compound (b) selected from the group consisting of Ci-C 10 - alkyl methacrylates, Ci-C 10 - alkyl acrylates, styrene, vinyl caprolactam, vinyl acetate and combinations thereof; - at least one compound F of formula I: R-(OE) x -OH (I) Where R represents the straight chain C6-C 40 -alkyl or branched C6-C 40 -alkyl, OE represents oxyethylidene, and x represents a number from 1 to 50.

12. An aqueous rheological agent R, combination of or comprising: - at least one water-soluble copolymer P prepared by polymerization reaction of the following substances in the presence of at least one compound E selected from the group consisting of dialkyl sulfosuccinates, dialkyl sulfosuccinate sodium salts and combinations thereof: • at least one compound (a) selected from the group consisting of methacrylic acid, methacrylic acid salts, methacrylic acid oligomers, methacrylic acid oligomer salts, acrylic acid, acrylic acid salts, acrylic acid oligomers, acrylic acid oligomer salts and combinations thereof; • at least one compound (b) selected from the group consisting of Ci-C 10 - alkyl methacrylates, Ci-C 10 - alkyl acrylates, styrene, vinyl caprolactam, vinyl acetate and combinations thereof; - at least one compound F of formula I: R-(OE) x -OH (I) Where R represents the straight chain C6-C 40 -alkyl or branched C6-C 40 -alkyl, OE represents oxyethylidene, and x represents a number from 1 to 50.

13. The aqueous rheological agent R according to claim 12, wherein the polymer P and the compound F are as defined in any one of claims 2 to 6.

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