Paper or cardboard sizing composition

Abstract

The present invention relates to a surface sizing composition for paper or cardboard, as well as a sizing method using said composition. This sizing composition comprises a polymer of at least one hydrophobic monomer and a polyvinyl amine.

Description

Title of the invention: Paper or cardboard sizing composition Technical field of the invention

[0001] The present invention relates to a composition for sizing paper or cardboard, as well as a sizing process using said composition. Prior art

[0002] The paper industry is constantly seeking to improve its paper, cardboard or similar manufacturing processes, particularly with regard to cost reduction, yield, productivity or even the properties of the final product.

[0003] This is particularly the case for the packaging industry which is looking for paper, cardboard or similar materials with better performance, in particular resistance to liquids (such as water, oils or greases) and printability, in order to meet current ecological challenges by replacing plastic packaging.

[0004] One of the main problems encountered with paper or cardboard packaging is the tendency of cellulose fibers to absorb liquids. This results in a reduction in the strength properties of the paper or cardboard in humid conditions, and diffusion of the inks during printing, leading to a blurred or running pattern.

[0005] To counter this phenomenon, the paper or cardboard undergoes a sizing step, giving it a barrier effect against liquids.

[0006] The purpose of sizing is therefore twofold: 1) by providing increased resistance to humidity and 2) by allowing the inks to remain on the surface of the paper or cardboard and dry there, rather than being absorbed.

[0007] There are two types of sizing, internal sizing and surface sizing. The main purpose of internal sizing is to improve moisture resistance, while the main purpose of surface sizing is to improve printability.

[0008] In the case of internal sizing, the sizing agent is added during the formation of the paper or cardboard sheet, whereas in the case of surface sizing, the sizing agent is applied in the form of a liquid composition to the surface of the paper or cardboard web.

[0009] Historically, the sizing agent is starch, which improves the strength properties and smoothes the surface of the paper or board. However, starch is hydrophilic, which reduces the wet strength of the paper or board.

[0010] Solutions have therefore been developed combining starch with hydrophobizing agents. The most common hydrophobizing agents are alkenyl succinic anhydride (ASA) and alkyl ketene dimer (AKD). Apart from these compounds, synthetic polymers have also been developed, among the most common examples are polystyrenes, in particular polystyrene acrylate emulsions (SAE), polystyrene maleic anhydride polymers (SMA), styrene acrylic acid polymers (SAA) or polyurethane dispersions (PUD). Among these hydrophobizing agents, alkenyl succinic anhydride (ASA) and alkyl ketene dimer (AKD) are mainly used for internal sizing, whereas synthetic polymers are mainly used for surface sizing, with polystyrene acrylate emulsions (SAE) being the most widespread.

[0011] The Applicant has discovered a new sizing composition offering better properties of resistance to liquids (such as water, oils or greases) and printability on paper or cardboard. This composition combines a hydrophobic polymer and a polyvinyl amine.

[0012] Furthermore, the polyvinyl amine can partially replace the hydrophobic polymer, which makes it possible, when recycling the paper or cardboard obtained by sizing the composition according to the invention, to give the latter better repulpability properties and mechanical strength, because the polyvinyl amine remains fixed on the recycled cellulose fibers unlike the hydrophobic polymer, which, due to its hydrophobic nature, will tend to form insoluble aggregates of adhesive particles ("stickies" in English). Replacing part of the hydrophobic polymer with polyvinyl amine therefore also makes it possible to reduce the formation of stickies which are harmful during the preparation of recycled paper or cardboard.

[0013] The composition of the invention therefore makes it possible to improve the properties of resistance to liquids (such as water, oils or greases) and printability, but also to improve the recycling of paper or cardboard which has undergone a sizing step.

[0014] The present invention is part of a principle of environmental awareness and the impact of industries and humans on the planet. Thanks to the sizing composition of the invention, it is possible to reduce the quantity of polymer used to obtain performances equivalent to the solutions of previous parts, thus reducing the emissions of greenhouse gases such as CO2 associated with the manufacture of synthetic polymers. Statement of the invention

[0015] The present invention relates to a paper or cardboard sizing composition comprising at least: [a] a polymer S2 comprising at least 40 mol% of a hydrophobic monomer A chosen from: (i) monomers of formula I:

[0016] [Chem.l]

[0017] where R1 and R2 are, independently, selected from the group consisting of a hydrogen atom, an alkyl chain of 1 to 4 carbons, and a halogen (F, Cl, Br, I); ii) (meth)acrylic acid ester monomers; iii) vinyl ester monomers (-C=COC(=O)-); iv) their mixtures; [b] a polyvinyl amine. The weight ratio between S2 polymer and polyvinyl amine is between 55 / 45 and 99 / 1.

[0018] The monomer of formula I comprises a single group R2, which is in the ortho, meta or para position, relative to the main substituent CRi=CH2.

[0019] The present invention also relates to a method for sizing paper or cardboard using the sizing composition according to the invention. Description of the invention

[0020] By "gluing" we mean both gluing and bonding, each of the terms being interchangeable.

[0021] By "polymer" is meant a homopolymer prepared from a monomer or a copolymer prepared from at least two different monomers, the monomers being chosen from: anionic hydrophilic monomers, cationic hydrophilic monomers, non-ionic hydrophilic monomers, zwitterionic hydrophilic monomers, hydrophobic monomers, and mixtures thereof.

[0022] By "hydrophilic monomer" is meant a monomer which has an octanol / water partition coefficient, Kow, less than or equal to 1, in which the partition coefficient Kow is determined at 25°C in an octanol / water mixture with a volume ratio of 1 / 1, at a pH between 6 and 8.

[0023] By "hydrophobic monomer" is meant a monomer which has an octanol / water partition coefficient, Kow, greater than 1, in which the partition coefficient Kow is determined at 25°C in an octanol / water mixture having a volume ratio of 1 / 1, at a pH between 6 and 8.

[0024] The octanol / water partition coefficient, Kow, represents the ratio of concentrations (g / L) of a monomer between the octanol phase and the aqueous phase. It is defined as follows:

[0025] [Math.l] \monomer\ ... ^ow ~ [moiwmèré^

[0026] By "water-soluble polymer" is meant a polymer which gives an aqueous solution without insoluble particles when dissolved under stirring at 25°C and with a concentration of 10 gL 1 in deionized water.

[0027] According to the invention, “X and / or Y” means “X”, or “Y”, or “X and Y”.

[0028] Also part of the invention are all possible combinations between the various embodiments disclosed, whether preferred or exemplary. Furthermore, when ranges of values ​​are indicated, the limits are part of these ranges. The disclosure also includes all combinations between the limits of these ranges of values. For example, the ranges of values ​​"1-20, preferably 5-15", imply the disclosure of the ranges "1-5", "1-15", "5-20" and "15-20" and the values ​​1, 5, 15 and 20.

[0029] The molecular weight is determined by the intrinsic viscosity of the polymer. The intrinsic viscosity can be measured by methods known to those skilled in the art and can be calculated from the reduced viscosity values ​​for different polymer concentrations by graphical method consisting of plotting the reduced viscosity values ​​(y-axis) on the concentration (x-axis) and extrapolating the curve to zero concentration. The intrinsic viscosity value is plotted on the y-axis or by using the least squares method. The molecular weight can then be determined by the Mark-Houwink equation: [q] = KM“ [q] represents the intrinsic viscosity of the polymer determined by the solution viscosity measurement method. K represents an empirical constant. M represents the molecular weight of the polymer, a represents the Mark-Houwink coefficient. K and a depend on the particular polymer-solvent system.

[0030] All of the particular and / or preferred modes described in the invention can be combined provided that they are not incompatible. Glue composition

[0031] The present invention relates to a paper or cardboard sizing composition comprising at least: [a] a polymer S2 comprising at least 40 mol% of a hydrophobic monomer A chosen from: (i) monomers of formula I:

[0032] [Chem.l] SL \ R, (I)

[0033] where Ri and R2 are, independently, a hydrogen atom, an alkyl chain of 1 to 4 carbons, or a halogen (F, Cl, Br, I); (ii) (meth)acrylic acid ester monomers; iii) vinyl ester monomers (-C=COC(=O)-); iv) their mixtures; [b] a polyvinyl amine. The weight ratio between S2 polymer and polyvinyl amine is between 55 / 45 and 99 / 1.

[0034] Polymer S2

[0035] Polymer S2 is a water-insoluble polymer.

[0036] By "water-insoluble" is meant a polymer which, once placed in deionized water, does not dissolve completely and remains at least partly (at least 40% by weight) in the form of solid particles in the deionized water (after 1 hour of stirring at 200 rpm, at 25°C and with a concentration of 5 gL ').

[0037] The polymer S2 can be non-ionic, cationic or anionic.

[0038] The polymer S2 is obtained from at least 40 mol% of a hydrophobic monomer Chosen from: (i) monomers of formula I:

[0039] [Chem.l] R

[0040] where R1 and R2 are, independently, a hydrogen atom, an alkyl chain of 1 to 4 carbons, or a halogen (F, Cl, Br, I); (ii) (meth)acrylic acid ester monomers; iii) vinyl ester monomers (-C=COC(=O)-); iv) their mixtures.

[0041] The hydrophobic monomer A is advantageously chosen from the monomers of formula I, the (meth)acrylic acid ester monomers, the vinyl ester monomers (-C=COC(=O)-) and their mixtures.

[0042] The hydrophobic monomer A may be of formula I:

[0043] [Chem.l]

[0044] Where R1 and R2 are, independently, a hydrogen atom, an alkyl chain of 1 to 4 carbons, or a halogen (F, Cl, Br, I).

[0045] Advantageously, the hydrophobic monomer A of formula I is chosen from styrene, ortho-chlorostyrene, meta-chlorostyrene, para-chlorostyrene, ortho-bromostyrene, meta-bromostyrene, para-bromostyrene, ortho-iodostyrene, meta-iodostyrene, para-iodostyrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, ortho-ethylstyrene, meta-ethylstyrene, para-ethylstyrene, ortho-propylstyrene, meta-propylstyrene, para-propylstyrene, ortho-t-butylstyrene, meta-t-butylstyrene, para-t-butylstyrene and mixtures thereof.

[0046] The amount of hydrophobic monomer A of formula I in the polymer S2 is advantageously at least 1 mol%, preferably at least 5 mol%, more preferably at least 10 mol%, even more preferably at least 20 mol%; and advantageously at most 99 mol%, preferably at most 95 mol%, more preferably at most 90 mol% and even more preferably at most 80 mol% (relative to the total amount of monomers of the polymer S2). It is advantageously between 33 and 67 mol%, preferably between 40 and 60 mol%, more preferably between 45 and 55 mol%.

[0047] The hydrophobic monomer A ester of (meth)acrylic acid advantageously results from the reaction between (meth)acrylic acid and an alcohol having a hydrocarbon group of C1 to C30, preferably C1 to C25, more preferably C1 to C20, even more preferably C1 to C15, the hydrocarbon group of the alcohol being able to be saturated or unsaturated, linear, branched or cyclic, optionally substituted by one or more heteroatoms chosen from N, O, P and S, and / or optionally substituted by one or more groups chosen from acid, aryl, ester, amine, amide, carbamate, hydroxyl, ether (ether advantageously C2 or C3), nitrile, vinyl, allyl, thioether, sulfonic or halogen groups.

[0048] Advantageously, the hydrophobic monomer A (meth)acrylic acid ester is chosen from: methyl (meth)acrylate; ethyl (meth)acrylate; butyl (meth)acrylate; tert-butyl (meth)acrylate; isobutyl (meth)acrylate; 2-ethylhexyl (meth)acrylate; ethylene glycol (meth)acrylate; octyl (meth)acrylate; lauryl (meth)acrylate; stearyl (meth)acrylate; dialkyl aminoalkyl acrylates, such as dimethylaminoethyl (meth)acrylate, their acidified or quaternized salts; and their mixtures.

[0049] The hydrophobic monomer A vinyl ester advantageously has a C1 to C30 hydrocarbon group, preferably C1 to C25, more preferably C1 to C20, even more preferably C1 to C15, the hydrocarbon group possibly being saturated or unsaturated, linear, branched or cyclic, optionally substituted by one or more heteroatoms chosen from N, O, P and S, and / or optionally substituted by one or more groups chosen from acid, aryl, ester, amine, amide, carbamate, hydroxyl, ether (advantageously C2 or C3 ether), nitrile, vinyl, allylic, thioether, sulfonic or halogen groups.

[0050] Advantageously, the hydrophobic monomer A vinyl ester is chosen from vinyl acetate, vinyl propionate, vinyl laurate, vinyl versatates of formula (II) CH2=CH-OC(=O)-C(CH3)(Rx)(Ry), with Rx + Ry representing a total number of carbon atoms between 5 and 8.

[0051] As vinyl versatate of formula (II), mention may be made, for example, of those from the Veova® range from the company Hexion, such as Veova® 9, 10 and 11.

[0052] The amount of hydrophobic monomer A (meth)acrylic acid ester in the polymer S2 is advantageously at least 1 mol%, preferably at least 5 mol%, more preferably at least 10 mol%, even more preferably at least 20 mol%; and advantageously at most 99 mol%, preferably at most 95 mol%, more preferably at most 90 mol% and even more preferably at most 80 mol%, it is advantageously between 33 and 67 mol%, preferably between 40 and 60 mol%, more preferably between 45 and 55 mol%.

[0053] The amount of hydrophobic monomer A vinyl ester in the polymer S2 is advantageously at least 1 mol%, preferably at least 5 mol%, more preferably at least 10 mol%, even more preferably at least 20 mol%; and advantageously at most 99 mol%, preferably at most 95 mol%, more preferably at most 90 mol% and even more preferably at most 80 mol%, it is advantageously between 33 and 67 mol%, preferably between 40 and 60 mol%, more preferably between 45 and 55 mol%.

[0054] In a preferred embodiment, the polymer S2 consists of hydrophobic monomer A.

[0055] In a preferred embodiment, the polymer S2 consists of: - 33 to 67 mol% of monomer of formula I, preferably between 40 and 60 mol%, more preferably between 45 and 55 mol%; and - 33 to 67 mol% of (meth)acrylic acid ester monomer and / or vinyl ester, preferably between 40 and 60 mol%, more preferably between 45 and 55 mol%.

[0056] According to a particular embodiment, the polymer S2 has a ratio between the monomer(s) of formula I and the (meth)acrylic acid ester monomer(s) advantageously between 2:1 and 1:2, preferably between 1.5:1 and 1:1.5, and more preferably the ratio is 1:1.

[0057] According to a particular embodiment, the polymer S2 has a ratio between the monomer(s) of formula I and the vinyl ester monomer(s) (-C=COC(=O)-) advantageously between 2:1 and 1:2, preferably between 1.5:1 and 1:1.5, and more preferably the ratio is 1:1.

[0058] According to a particular embodiment, the polymer S2 has a ratio between (1) the monomer(s) of formula I and (2) the (meth)acrylic acid ester monomer(s) and the vinyl ester monomer(s) (-C=COC(=O)-) advantageously included between 2:1 and 1:2, preferably between 1.5:1 and 1:1.5, and more preferably the ratio is 1:1.

[0059] The polymer S2 may further comprise at least one monomer B different from the hydrophobic monomer A, chosen from hydrophilic non-ionic monomers, hydrophilic anionic monomers, hydrophilic cationic monomers, hydrophilic zwitterionic monomers.

[0060] Advantageously, the non-ionic hydrophilic monomer(s) B are chosen, in particular, from the group comprising water-soluble vinyl monomers, such as acrylamide, methacrylamide, N-alkylacrylamides, N-alkylmethacrylamides, N,N-dialkyl acrylamides (for example N,N-dimethylacrylamide or N,N-diethylacrylamide), N,N-dialkylmethacrylamides, alkoxylated esters of acrylic acid, alkoxylated esters of methacrylic acid, N-vinylpyrrolidone, N-methylol(meth)acrylamide, N-vinyl caprolactam, N-vinylformamide (NVF), N-vinyl acetamide, N-vinyl imidazole, N-vinyl succinimide, acryloyl morpholine (ACMO), glyceryl methacrylate, diacetone acrylamide, methacrylic anhydride, maleic anhydride, itaconic anhydride, itaconamide, hydroxyalkyl (meth)acrylate, thioalkyl (meth)acrylate, isoprenol and its alkoxylated derivatives, hydroxyethyl (meth)acrylates and their alkoxylated derivatives,hydroxypropylacrylate and its alkoxylated derivatives, vinyl acetate, and mixtures thereof. Among these non-ionic monomers, the alkyl groups are advantageously C1-C5, more advantageously C1-C3. Preferably, the hydrophilic non-ionic monomers B are acrylamide and N-methylol acrylamide.

[0061] Advantageously, the other anionic hydrophilic monomer(s) B may be chosen from a broad group. These monomers may have a vinyl function, in particular acrylic, maleic, fumaric, malonic, itaconic, or allyl. They may also contain a carboxylate, phosphonate, phosphate, sulfonate group, or another group with an anionic charge.Preferred monomers belonging to this class are, for example, acrylic acid, methacrylic acid, dimethylacrylic acid, itaconic acid, Cr-C3 itaconic acid hemiesters, acryloyl chloride, crotonic acid, maleic acid, fumaric acid, 3-acrylamido-3-methylbutanoic acid, strong acid monomers having, for example, a sulfonic acid or phosphonic acid function such as vinylsulfonic acid, vinylphosphonic acid, allylsulfonic acid, methallylsulfonic acid, 2-methylidenepropane-1,3-disulfonic acid, 2-sulfoethylmethacrylate, sulfopropylmethacrylate, sulfopropylacrylate, allylphosphonic acid, ethylene glycol methacrylate phosphate, styrene sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (ATBS), 2- . acrylamido-2-methylpropane disulfonic acid, 3-allyloxy-2-hydroxypropane sulfonic acid, diethylallylphosphonate; the water-soluble salts of all these monomers such as their alkali metal, alkaline earth metal or ammonium salts; and mixtures thereof. Also included are the hemiesters of maleic acid or itaconic acid, their salts and mixtures thereof. Preferably, the hydrophilic anionic monomer B is (meth)acrylic acid.

[0062] In a particular embodiment, the anionic hydrophilic monomer(s) B may be salified. It may also be a mixture of acid form and salified form, for example a mixture of acrylic acid and acrylate.

[0063] By salified is meant the substitution of a proton of at least one acid function of the type -Ra(=O)-OH (with R= P, S or C) of the anionic monomer by a metal cation or organic cation to form a salt of the type -Ra(=O)-OX (X being a metal cation or organic cation). In other words, the non-salified form corresponds to the acid form of the monomer, for example Rb-C(=O)-OH in the case of the carboxylic acid function, whereas the salified form of the monomer corresponds to the form Rb-C(=O)-O- X+, X+ corresponding to an alkali metal cation or organic cation. The salification of the acid functions of the polymer S2 can be partial or total.

[0064] The salified form advantageously corresponds to the salts of alkali metals (Li, Na, K, etc.), of alkaline earth metals (Ca, Mg, etc.), and the organic cation is advantageously the ammonium ion or a tertiary ammonium. The preferred salts are the sodium salts.

[0065] Salification can be done before or after polymerization.

[0066] Advantageously, the cationic hydrophilic monomer(s) B may be chosen, in particular, from monomers of the vinyl type, in particular acrylamide, acrylic, allyl or maleic having an ammonium function, advantageously quaternary ammonium.Mention may be made, in particular and without limitation, of diallyldialkyl ammonium salts such as diallyl dimethyl ammonium chloride (DADMAC); acidified or quaternized salts of dialkyl-aminoalkyl(meth)ac rylamides, such as for example methacrylamido-propyl trimethyl ammonium chloride (MAPTAC), acrylamido-propyl trimethyl ammonium chloride (APTAC), acidified or quaternized salts of N,N-dimethylallylamine, acidified or quaternized salts of diallylmethylamine, acidified or quaternized salts of diallylamine, vinylamine obtained by the hydrolysis (basic or acidic) of an amide group -N(R2)-CO-Ri with Ri and R2 being, independently, a hydrogen atom or an alkylated chain of 1 to 6 carbons, vinylamine obtained by Hofmann degradation and mixtures thereof. Advantageously, the alkyl groups are . in C1-C7, preferably in C1-C3 and can be linear, cyclic, saturated or unsaturated chains.

[0067] A person skilled in the art will know how to prepare the quaternized monomers, for example using a quaternizing agent of the RX type, R being an alkyl group and X being a halogen or a sulfate.

[0068] By “quaternizing agent” we mean a molecule capable of alkylating a tertiary amine.

[0069] The quaternizing agent may be chosen from dialkyl sulfates comprising from 1 to 6 carbon atoms or alkyl halides comprising from 1 to 6 carbon atoms. Preferably, the quaternizing agent is chosen from methyl chloride, benzyl chloride, dimethyl sulfate or diethyl sulfate. In addition, the present invention also covers monomers of the DADMAC, APTAC and MAPTAC type whose counterion is a sulfate, a fluoride, a bromide or an iodide instead of the chloride.

[0070] The amount of monomer B in the polymer S2 is advantageously less than 60 mol%, preferably less than 50 mol%, more preferably less than 40 mol%, more preferably less than 30 mol%, more preferably less than 20 mol%, more preferably less than 10 mol%. When present, the monomer B in the polymer S2 represents at least 1 mol%.

[0071] The quantity of monomers B will be adjusted according to the conditions of preparation of polymer S2 and the use of the latter so that it remains insoluble in water.

[0072] The polymer S2 is conventionally obtained by direct emulsion polymerization according to the general knowledge of those skilled in the art.

[0073] The polymer S2 may be linear, branched or crosslinked. The polymer S2 may be branched or crosslinked, for example, using a branching agent and / or using a transfer agent.

[0074] The polymer S2 may comprise other hydrophobic monomers different from the hydrophobic monomer A, advantageously they represent at most 20 mol% of the polymer S2, preferably at most 15 mol%, more preferably at most 10 mol% and even more preferably at most 5 mol% relative to the total number of monomers of the polymer S2.

[0075] The quantities of the different monomers will be adjusted by those skilled in the art in order to reach 100 mol% during the preparation of the polymer S2.

[0076] In a particular embodiment, the polymer S2 is made up of monomers A and B, preferably it is made up of monomers A.

[0077] In a particular embodiment, the polymer S2 is structured with at least one branching agent. A structured polymer is a non-linear polymer with side chains.

[0078] The branching agent is advantageously chosen from: - structural agents, which may be chosen from the group comprising monomers with polyethylene unsaturation (having at least two unsaturated functions), such as for example vinyl functions, in particular allylic or acrylic, and examples which may be mentioned are methylene bis acrylamide (MBA), triallyamine, tetraallylammonium chloride, 1,2 dihydroxyethylene bis-(N-acrylamide), ethylene glycol (meth)acrylate, divinyl benzene; - monomers having at least two epoxy functions; - monomers having at least one unsaturated function and one epoxy function such as glycidyl (meth)acrylate; - macroinitiators such as polyperoxides, polyazos and polytransfer agents such as polymercaptants and polyols; - functionalized polysaccharides; - water-soluble metal complexes composed of: * a metal with a valence greater than 3 such as, by way of example and without limitation, aluminum, boron, zirconium or titanium, and * of a ligand carrying a hydroxyl function.

[0079] The amount of branching agent in the polymer S2 is advantageously between 1 and 100,000 ppm, preferably between 10 and 50,000 ppm, more preferably between 100 and 10,000 ppm.

[0080] In a preferred embodiment, the polymer S2 is devoid of branching agent.

[0081] Polyvinyl amine

[0082] Polyvinyl amine is a water-soluble polymer.

[0083] Polyvinyl amine can be obtained by partial or total Hofmann rearrangement of acrylamide, methacrylamide, acrylonitrile, and mixtures thereof; or by partial or total hydrolysis of the amide group -N(R2)-CO-Ri of a monomer of formula III:

[0084] [Chem.2] O 2 / ( Vf T jMjMjMj- Y y XT ...........t. HN C — R (neither)

[0085] where R1 and R2 are, independently, a hydrogen atom or an alkyl chain of 1 to 6 carbons. Hofmann's rearranged arrangement

[0086] The Hofmann rearrangement reaction consists, in particular, of converting amide or nitrile functions into amine functions (for example by formation of vinylamine monomeric units) by involving two main coefficients (expressed in molar ratios): - Alpha coefficient = hypohalide (alkali metal hypohalide and / or alkaline earth metal hypohalide) / amide and / or nitrile functions; - Beta coefficient = hydroxide (alkali metal hydroxide and / or alkaline earth metal hydroxide) / hypohalide (alkali metal hypohalide and / or alkaline earth metal hypohalide).

[0087] A hypohalide is an oxy-anion, for example hypochlorite CIO. Preferably, it is sodium hypochlorite.

[0088] An “alkali hypohalide” means a hypohalide of at least one alkali metal, for example NaOCl, KOBr or NaOCl+KOBr. The same applies to an alkaline earth hypohalide.

[0089] By “alkali” is meant an alkali metal, advantageously lithium, sodium or potassium.

[0090] By “alkaline earth” is meant an alkaline earth metal, advantageously calcium or magnesium.

[0091] An “alkali hydroxide” means a hydroxide (OH-) of at least one alkali metal, for example NaOH, KOH or NaOH+KOH. The same applies to alkaline earth hydroxide. Preferably, it is sodium hydroxide.

[0092] The Hofmann rearrangement may be carried out before, during or after the polymerization of the monomers constituting a PI polymer, including acrylamide, methacrylamide, acrylonitrile and / or mixtures thereof.

[0093] Advantageously, the Hofmann degradation reaction comprises at least the following steps: 1) dilution (advantageously in water) of the solution comprising the polymer PI in order to form a dilute solution of the polymer (SD1); 2) addition of the hypohalide and the hydroxide, in order to form a dilute solution (SD2); 3) reaction between the PI polymer, the hypohalide and the hydroxide, in order to obtain a solution comprising polyvinyl amine (SD3).

[0094] Advantageously in step 1), the concentration of the polymer PI in the dilute solution SD1 of the polymer PI is between 1 and 40% by weight relative to the weight of the SD1, more preferably between 2 and 30% and even more preferably between 5 and 25%.

[0095] Advantageously in step 2), the coefficient Alpha = hypohalide / amide and / or nitrile functions is between 0.1 and 1.0, preferably between 0.3 and 1.0 and more preferably between 0.5 and 1.0.

[0096] Advantageously in step 2), the coefficient Beta = hydroxide / hypohalide is between 0.5 and 4.0.

[0097] Advantageously in step 3), the reaction between the polymer PI, the hypohalide and the hydroxide lasts between 10 seconds and 180 minutes, preferably between 1 minute and 120 minutes, more preferably between 10 minutes and 90 minutes, and even more preferably between 30 minutes and 75 minutes.

[0098] Advantageously in step 3), the reaction between the polymer PI, the hypohalide and the hydroxide is carried out at a temperature between 10 and 30°C, preferably between 15 and 25°C.

[0099] At the end of step 3), the polyvinyl amine according to the invention is obtained.

[0100] In a particular embodiment according to the invention, at the end of step 3), the polyvinyl amine can be functionalized with an aldehyde to give an aldehyde polyvinyl amine.

[0101] The aldehyde is advantageously chosen from glyoxal, glutaraldehyde, furan-dialdehyde, adipaldehyde, succinaldehyde, starch dialdehyde, 2,2-dimethoxyethanal, diepoxy compounds and mixtures thereof. Preferably, it is glyoxal.

[0102] In order to stabilize the amine functions produced, a person skilled in the art can use at least one quaternary ammonium derivative as described in document JP 57077398. The purpose of this quaternary ammonium derivative is to avoid the reaction between the amine functions and the residual amide functions. The addition of these agents can be carried out separately, simultaneously, in a mixture or not, in any order of introduction, and at one or more injection points. Advantageously, the addition of these agents is carried out in step 1).

[0103] During the Hofmann rearrangement, the cationicity of the polymer increases by the use / consumption, in whole or in part, of an alkali or alkaline earth hypohalide.

[0104] Hydrolysis of the monomer of formula (III)

[0105] Advantageously, the monomer(s) of formula (III) are chosen from: N-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N-vinyl-N-ethylacetamide, N-vinylpropianamide, N-vinyl-N-methylpropianamide and N-vinylbutyramide. Preferably, it is N-vinylformamide.

[0106] The hydrolysis of the monomer of formula (III) can be carried out under the action of an acid (acid hydrolysis) or a base (basic hydrolysis). Preferably, it is a basic hydrolysis.

[0107] The acid hydrolysis can be carried out using any Brpnsted acid known to those skilled in the art, by way of example and in a non-limiting manner, mention may in particular be made of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid.

[0108] The acid hydrolysis is advantageously carried out at a pH between 0 and 2, preferably between 0 and 1.

[0109] The acid hydrolysis is advantageously carried out at a temperature between 60 and 100°C, preferably between 70 and 90°C, more preferably between 75 and 85°C.

[0110] The duration of the acid hydrolysis step is advantageously between 120 minutes and 720 minutes, preferably between 180 minutes and 600 minutes, more preferably between 300 minutes and 540 minutes.

[0111] Basic hydrolysis can be carried out using any base known to those skilled in the art, by way of example and in a non-limiting manner, mention may in particular be made of sodium hydroxide, potassium hydroxide, and ammonia.

[0112] The basic hydrolysis is advantageously carried out at a pH between 8 and 14, preferably between 8 and 13, more preferably between 9 and 12.

[0113] The basic hydrolysis is advantageously carried out at a temperature between 60 and 100°C, preferably between 70 and 90°C, more preferably between 75 and 85°C.

[0114] The duration of the basic hydrolysis step is advantageously between 60 minutes and 480 minutes, preferably between 120 minutes and 420 minutes, more preferably between 240 minutes and 360 minutes.

[0115] Depending on the amount of acid or base added, the monomers of formula (III) are partially or completely converted into an amine function.

[0116] Once the hydrolysis reaction is complete, the pH is advantageously adjusted between 6 and 9. Polyvinyl amine

[0117] The quantity of amine functions (-CH2-CH(NH2)- group) in the polyvinyl amine is between 1 and 100 mol%, preferably between 10 and 90 mol%, more preferably between 20 and 80 mol%, more preferably between 30 and 70 mol%, and even more preferably between 35 and 60 mol%. The quantity of amine functions in the polyvinyl amine may in particular be between 30 and 100 mol%.

[0118] The polyvinyl amine may further comprise at least one monomer chosen from hydrophilic non-ionic monomers other than acrylamide, methacrylamide, acrylonitrile and the monomer of formula (III); hydrophilic anionic monomers; hydrophilic cationic monomers other than amines obtained after the Hofmann rearrangement of acrylamide, methacrylamide, acrylonitrile or the hydrolysis of the compound(s) of formula (III); hydrophilic zwitterionic monomers; and hydrophobic monomers.

[0119] Advantageously, the non-ionic hydrophilic monomer(s) (other than acrylamide, methacrylamide, acrylonitrile and the monomer of formula (III)) are chosen, in particular, from the group comprising water-soluble vinyl monomers, such as N-alkylacrylamides, N-alkylmethacrylamides, N,N-dialkylacrylamides (for example N,N-dimethylacrylamide or N,N-diethylacrylamide), N,N-dialkylmethacrylamides, alkoxylated esters of acrylic acid, alkoxylated esters of methacrylic acid, N-vinylpyrrolidone, N-methylol(meth)acrylamide, N-vinyl caprolactam, N-vinyl imidazole, N-vinyl succinimide, acryloyl morpholine (ACMO), glycidyl methacrylate, glyceryl methacrylate, diacetone acrylamide, methacrylic anhydride, maleic anhydride, itaconic anhydride, itaconamide, hydroxyalkyl (meth)acrylate, thioalkyl (meth)acrylate, isoprenol and its alkoxylated derivatives,hydroxyethyl(meth)acrylates and their alkoxylated derivatives, hydroxypropylacrylate and its alkoxylated derivatives, vinyl acetate, and mixtures thereof. Among these non-ionic monomers, the alkyl groups are advantageously C1-C5, more advantageously C1-C3. They are preferably linear alkyls.

[0120] The polyvinyl amine advantageously comprises less than 50 mol% of hydrophilic non-ionic monomer (different from acrylamide, methacrylamide, acrylonitrile and the monomer of formula (III)), preferably less than 40 mol% and more advantageously less than 30 mol%.

[0121] Advantageously, the other anionic hydrophilic monomer(s) may be chosen from a broad group. These monomers may have a vinyl function, in particular acrylic, maleic, fumaric, malonic, itaconic, or allyl. They may also contain a carboxylate, phosphonate, phosphate, sulfonate group, or another group with anionic charge. Preferred monomers belonging to this class are, for example, acrylic acid, methacrylic acid, dimethylacrylic acid, itaconic acid, Cr-C3> itaconic acid hemiesters, acryloyl chloride, crotonic acid, maleic acid, fumaric acid, 3-acrylamido-3-methylbutanoic acid, strong acid monomers having, for example, a sulfonic acid or phosphonic acid function such as vinylsulfonic acid, vinylphosphonic acid, allylsulfonic acid, methallylsulfonic acid, 2-methylidenepropane-1,3-disulfonic acid, 2- sulfoethylmethacrylate, sulfopropylmethacrylate, sulfopropylacrylate, allylphosphonic acid, ethylene glycol methacrylate phosphate, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid (ATBS), 2-acrylamido-2-methylpropane disulfonic acid, 3-allyloxy-2-hydroxypropane sulfonic acid, diethylallylphosphonate, carboxyethyl acrylate; the water-soluble salts of all these monomers such as their alkali metal, alkaline earth metal, or ammonium salts; and mixtures thereof. Also included are the hemiesters of maleic acid or itaconic acid, their salts, and mixtures thereof.

[0122] In a particular embodiment, the anionic hydrophilic monomer(s) may be salified. It may also be a mixture of acid form and salified form, for example a mixture of acrylic acid and acrylate.

[0123] By salified is meant the substitution of a proton of at least one acid function of the type -Ra(=O)-OH (with R= P, S or C) of the anionic monomer by a metal cation or organic cation to form a salt of the type -Ra(=O)-OX (X being a metal cation or organic cation). In other words, the non-salified form corresponds to the acid form of the monomer, for example Rb-C(=O)-OH in the case of the carboxylic acid function, whereas the salified form of the monomer corresponds to the form Rb-C(=O)-0 X+, X+ corresponding to an alkali cation or organic cation. The salification of the acid functions of the polymer can be partial or total.

[0124] The salified form advantageously corresponds to the alkali metal salts (Li, Na, K...), alkaline earth metals (Ca, Mg...), and the organic cation is advantageously the ammonium ion or a tertiary ammonium. The preferred salts are sodium salts.

[0125] Salification can be done before or after polymerization.

[0126] The polyvinyl amine advantageously comprises less than 50 mol% of hydrophilic anionic monomer, preferably less than 40 mol% and more advantageously less than 30 mol%.

[0127] Advantageously, the hydrophilic cationic monomer(s) (different from the monomer having undergone the Hofmann degradation reaction or hydrolysis) are chosen from monomers derived from vinyl-type units (advantageously acrylamide, acrylic, allyl or maleic), these monomers having a quaternary ammonium function. In particular and in a non-limiting manner, mention may be made of diallyldialkyl ammonium salts such as diallyl dimethyl ammonium chloride (DADMAC); quaternized salts of dialkyl-aminoalkylacrylamides; quaternized salts of dialkyl-aminoalkyl methacrylamides, such as methacrylamido-propyl trimethyl ammonium chloride (MAPTAC), acrylamido- propyl trimethyl ammonium (APTAC), quaternized salts of dialkyl aminoalkyl acrylate, such as quaternized dimethylaminoethyl acrylate, quaternized salts of dialkyl aminoalkyl methacrylate, such as quaternized dimethylaminoethyl methacrylate, acidified or quaternized salts of N,N-dimethylallylamine; acidified or quaternized salts of diallylmethylamine; acidified or quaternized salts of diallylamine; and mixtures thereof. Advantageously, the alkyl groups are C1-C3. Preferably, the monomer having a quaternary amine function is diallyl dimethyl ammonium chloride (DADMAC).

[0128] A person skilled in the art will know how to prepare the quaternized monomers, for example using a quaternizing agent of the RX type, R being an alkyl group and X being a halogen or a sulfate.

[0129] By “quaternizing agent” we mean a molecule capable of alkylating a tertiary amine.

[0130] The quaternizing agent may be chosen from dialkyl sulfates comprising from 1 to 6 carbon atoms or alkyl halides comprising from 1 to 6 carbon atoms. Preferably, the quaternizing agent is chosen from methyl chloride, benzyl chloride, dimethyl sulfate or diethyl sulfate. In addition, the present invention also covers monomers of the DADMAC, APTAC and MAPTAC type whose counterion is a sulfate, a fluoride, a bromide or an iodide instead of the chloride.

[0131] The polyvinyl amine advantageously comprises less than 50 mol% of hydrophilic cationic monomer (different from the monomer having undergone the Hofmann degradation reaction or hydrolysis), preferably less than 40 mol% and more advantageously less than 30 mol%.

[0132] The quantities of the different monomers will be adjusted by those skilled in the art so as not to exceed 100 mol% during the preparation of the polyvinyl amine.

[0133] The polyvinyl amine advantageously has a weight-average molecular weight of between 10,000 g / mol and 1,000,000 g / mol, preferably between 20,000 g / mol and 500,000 g / mol, more preferably between 30,000 g / mol and 300,000 g / mol.

[0134] The polyvinyl amine may further be structured with at least one branching agent. A structured polymer is a non-linear polymer with side chains.

[0135] The branching agent is advantageously chosen from: - structural agents, which may be chosen from the group comprising monomers with polyethylene unsaturation (having at least two unsaturated functions), such as for example vinyl functions, in particular allylic or acrylic, and we can cite for example methylene bis acrylamide (MBA), triallyamine, tetraallylammonium chloride, 1,2 dihydroxyethylene bis-(N-acrylamide), ethylene glycol (meth)acrylate; - monomers having at least two epoxy functions; - monomers having at least one unsaturated function and one epoxy function such as glycidyl (meth)acrylate; - macroinitiators such as polyperoxides, polyazos and polytransfer agents such as polymercaptants and polyols; - functionalized polysaccharides; - water-soluble metal complexes composed of: * a metal with a valence greater than 3 such as, by way of example and without limitation, aluminum, boron, zirconium or titanium, and * of a ligand carrying a hydroxyl function.

[0136] In a preferred embodiment, the polyvinyl amine is free of branching agent.

[0137] In a particular embodiment, the polyvinyl amine comprises a transfer agent.

[0138] The transfer agent is advantageously chosen from methanol, isopropyl alcohol, sodium hypophosphite, calcium hypophosphite, magnesium hypophosphite, potassium hypophosphite, ammonium hypophosphite, formic acid, sodium formate, calcium formate, magnesium formate, potassium formate, ammonium formate, 2-mercaptoethanol, 3-mercaptopropanol, dithiopropylene glycol; thioglycerol; thioglycolic acid; thiohydracrylic acid; thiolactic acid; thiomalic acid; cysteine; aminoethanethiol; thioglycolates; allylic phosphites; allylic mercaptans, sodium methallysulfonate; calcium methallysulfonate; magnesium methallysulfonate; potassium methallysulfonate; ammonium methallysulfonate; polythiols and mixtures thereof. Preferably, the transfer agent is sodium hypophosphite, sodium formate or mixtures thereof.

[0139] In a particular embodiment, the polyvinyl amine is free of transfer agent.

[0140] In a preferred embodiment, the polyvinyl amine is prepared according to the process described by the Applicant in document FR2305149.

[0141] In a particular embodiment, the polyvinyl amine may react with α,[3-unsaturated alkylcarbonyl compounds, including amides, esters and acids under acidic conditions to form a Michael adduct.

[0142] Composition

[0143] The quantity of polymers S2 and polyvinyl amine advantageously represents between 1 and 100% by weight of the active material of the sizing composition, preferably between 5 and 100% by weight, more preferably between 20 and 100% by weight.

[0144] The quantity of polymers S2 and polyvinyl amine advantageously represents between 0.5 and 15% by weight relative to the total weight of the sizing composition, preferably between 1 and 10% by weight, more preferably between 1.5 and 8% by weight.

[0145] By "active material" of the sizing composition, we mean the S2 and polyvinyl amine polymers and, when present, the starch, with the exception of the solvent(s) and any other additives, the solvent advantageously corresponding to water.

[0146] The weight ratio between the polymer S2 and the polyvinyl amine is between 55 / 45 and 99 / 1, more preferably between 60 / 40 and 99 / 1, more preferably between 80 / 20 and 95 / 5.

[0147] The sizing composition may also comprise starch.

[0148] The amount of starch in the sizing composition is advantageously between 0 and 80% by weight relative to the total weight of the active material of the sizing composition, preferably between 10 and 80% by weight, preferably between 10 and 75% by weight.

[0149] In addition to the polymer S2 and the polyvinyl amine, the sizing composition may comprise additives conventionally used for sizing paper or cardboard by those skilled in the art; for example, aluminum chloride, enzymes, dyes, optical brighteners, an antifoaming agent, paraffin, mineral or vegetable waxes, surfactants, polysaccharides other than starch, other polymers (for example polyvinyl alcohol or polyvinyl acetate) may be mentioned.

[0150] The amount of additives in the sizing composition generally does not exceed 50% by weight, preferably not 40% by weight and more preferably not 30% by weight, relative to the total weight of the active material of the sizing composition.

[0151] Mineral or vegetable waxes advantageously have a melting weight of between 40 and 65°C, preferably between 45 and 60°C, more preferably between 50 and 55°C.

[0152] The surfactants can be non-ionic, anionic or cationic, preferably they are non-ionic.

[0153] As surfactants, mention may be made, for example, of polyesters having a molecular weight of between 1000 and 3000 g / mol, condensation products between a poly(isobutenyl) succinic acid or its anhydride and a polyethylene glycol, block polymers having a molecular weight of between 2500 and 3500 g / mol, such as for example those sold under the names Hypermer®, sorbitan extracts, such as sorbitan monooleate or polyoleates, sorbitan isostearate, sorbitan or sorbitan sesquioleate, polyethoxylated sorbitan esters, or diethoxylated oleocetyl alcohol or tetraethoxylated laurylacrylate, condensation products of fatty alcohols higher than ethylene, such as the reaction product of oleyl alcohol with 2 ethylene oxide units; condensation products of alkylphenols and ethylene oxide, such as the reaction product of nonyl phenol with 4 ethylene oxide units. Preferably, it is sorbitol palmitate, optionally oxyethylenated, sorbitol stearic acid.

[0154] Examples of polysaccharides that may be mentioned include carboxymethylcellulose or any other chemically modified polysaccharide derivative.

[0155] The quantity of the different constituents of the sizing composition of the invention will be adjusted by those skilled in the art in order to reach 100% by weight.

[0156] The present invention also relates to a process for sizing paper or cardboard using the sizing composition according to the invention.

[0157] In a preferred embodiment, the sizing composition is used for surface sizing.

[0158] The invention and its advantages will be better illustrated by the following examples given to illustrate the invention, without however limiting it. Examples

[0159] List of abbreviations: PVAM: polyvinyl amine AA: sodium acrylate N VF: N-vinylformamide VA: Vinyl Amine APTAC: acrylamidopropyl trimethyl ammonium chloride

[0160] Description of the products used: Product A (PA): Polyvinyl amine (PVAM) from NVF, 50% hydrolyzed, with a molecular weight of 275,000 g / mol. Product B (PB): Polyvinyl amine (PVAM) from the Hofmann rearrangement on a polyacrylamide, 100% conversion of acrylamide, with a molecular weight of 150,000 g / mol. Product C (PC): Polyvinyl amine (NVF / AA copolymer 70 / 30 mol%) of which 50% is hydrolyzed NVF (i.e. NVF / VA / AA 35 / 35 / 30 mol%), with a molecular weight of 225,000 g / mol. Product D (PD): Polyvinyl amine (NVF / APTAC copolymer 50 / 50mol%), obtained by the Michael reaction on a 100% hydrolyzed poly(NVF), having a molecular weight of 235,000 g / mol. S2-A Polymer (Cationic) (SAE A): Product sold by Axchem under the name Axsize SS 8100 S2-B Polymer (Anionic) (SAE B): Product sold by Axchem under the name Axsize SS 2765 EP

[0161] Preparation of sizing compositions 1 to 14

[0162] In a reactor, 586g of water, 80g of native potato starch and 0.04g of amylase enzyme are weighed. This solution is heated to 72°C for 3 minutes, then to 85°C for 6 minutes. After that, 0.6g of zinc sulfate is added to eliminate the enzymes and then heated to 93-95°C for 12 minutes.

[0163] Water at 80°C is added to dilute this starch solution to 9% by weight.

[0164] We therefore obtain a starch solution having a concentration of 9% by weight. for a viscosity measured with a Brookfield LV1 viscometer, speed 100rpm, at 50 cps at 50°C.

[0165] To this starch solution are added the polymer S2 and the polyvinyl amine SAE and the polyinyl amine (PVAM) making it possible to obtain the sizing composition.

[0166] For sizing compositions 9 to 14, 0.4% by weight of polyaluminium chloride was added.

[0167] The sizing compositions 9 to 14 are summarized in Table 1.

[0168] Preparation of sizing compositions 15 to 21

[0169] In a reactor, the polymer S2 and the polyvinyl amine are mixed.

[0170] For sizing compositions 17 to 21, 0.4% by weight of polyaluminium chloride was added.

[0171] The sizing compositions 17 to 21 are summarized in Table 1.

[0172] [Tableauxl] Composition d’encollage Amidon (%) SAE (%) PVAM (%} Ratio SAE / PVAM SAE A SAE B PA PB PC PD Blanc - - - - - - - Composition 1 (Œxi 100 - - - - - - XXX / X X X X X Composition 2 (CEx) - 25 - — — - Composition 3 (CEx) 25 - - — — - Composition 4 (CEx) 12.5 xx xX:-: x — 12.5 - - 50 / 50 Composition 5 {Invt 75 20 - 5 - - 80 / 20 Composition 6 (Inv) 75 20 - - 5 - - 80 / 20 Composition 7 (Inv) 75 20 - - - 5 - 80 / 20 Composition S (Inv) 75 20 - - - - 5 80 / 20 Composition 9 (CEx) 75 - 25 - - - - 80 / 20 Composition 13 (Inv) 75 20 - - 5 - 80 / 20 Composition 14 (Inv) 7^ - 20 - - - 80 / 20 Composition 15 tCEx) - 100 - - — - 1002'0 Composition 16 (CEx) - - 100 - - 0 / 100 Composition 17 (CEx) 50 50 - - - 50 / 50 Composition 18 (Inv) - - 60 40 - - - 60 / 40 Composition 19 (Inv) - - 80 20 - - - 80 / 20 Composition 20 (Inv) - - 95 5 - - - 95.5 Composition 21 (Inv) - - 99 1 - - - 99 / 1 .

[0173] Table 1 - Active ingredient of sizing compositions (CEx=Counter-example, Inv=invention)

[0174] Gluing procedure

[0175] Two sizing methods were carried out to demonstrate the effect of the composition of the invention. - In a first series of tests, a Mathis AG is used for gluing, the roller speed being Itr / min, the pressure between the rollers 2 bars and the temperature of the gluing composition 60°C. The sizing composition is placed on a sheet of paper (100% recycled fibers), 90g / m2, placed in the running direction. The coated paper sheet is dried on a dryer at 117°C for 5 minutes. - In a second series of tests, a K303 multi coater is used for gluing, the speed being 8m / min, and the rod used being a lOpm threaded rod. The sizing composition is placed on a sheet of paper (100% recycled fibers), 90g / m2, placed in the running direction. The coated paper sheet is dried on a dryer at 117°C for 5 minutes. Tests

[0176] The different sizing compositions prepared previously are tested according to two parameters, the rate of deposition of the sizing composition on the sheet in paper and the Cobb 60 parameter, allowing to measure the absorption of the treated water sheet. The results are summarized in Table 2.

[0177] Deposition rate The deposition rate is calculated by measuring the amount of sizing compound that adheres to the sheet of paper by measuring the weight of the sheet before deposition and after deposition plus drying of the sheet. The higher the deposition rate, the better the sizing.

[0178] Cobb 60 Cobb 60 corresponds to the quantity of water absorbed by the glued sheet of paper after a period of 60s of contact with water (gr / m2). The less water the paper absorbs, the better the sizing. Results

[0179] [Tables2] Glue composition Deposition rate (¾) Cobb 60 (sr / m-) White - 145 Composition 1 (CEx) 331 137 Composition 2 (CEx) 3.51 128 Composition 3 (CEx) 3.10 38 Composition 4 (CEx) 3.31 Composition 5 (Inv) 3.31 24 Composition 6 (Inv) 3.39 27 Composition 7 (Inv) 3.47 26 Composition S tlnv) 25 Composition 9 <CEx» 3,44 35 Composition 10 (CEx) 3,10 54 Composition 11 (Inv) 3,35 19 Composition 12 (Inv) 3.26 23 Composition 13 (Inv) 3.43 21 Composition 14 (Inv) 3.39 Composition 15 (CEx) 1.46 48 Composition 16 (CEx) 1.43 132 Composition 17 (CEx) 1.29 64 Composition 18 (Inv) 1,39 77 Composition 19 (Inv) 1,29 15 Composition 20 (Inv) 1,34 19 Composition 21 (Inv) 1,31 33

[0180] Table 2 - Results of the deposition rate and Cobb 60 of the sizing compositions 1 to 21

Claims

Claims ^Claim 1] Paper or cardboard sizing composition comprising at least: [a] a polymer S2 comprising at least 40 mol% of a hydrophobic monomer A chosen from: i) the monomers of formula I: [Chem.l] w XR? a) Where R1 and R2 are, independently, chosen from the group consisting of a hydrogen atom, an alkylated chain of 1 to 4 carbons, and a halogen; ii) (meth)acrylic acid ester monomers; iii) vinyl ester monomers; iv) mixtures thereof; [b] a polyvinyl amine, the polymer S2 and the polyvinyl amine having a weight ratio of between 55 / 45 and 99 / 1.^Claim 2] Composition according to claim 1, characterized in that the hydrophobic monomer A of formula (I) is chosen from styrene, ortho-chlorostyrene, meta-chlorostyrene, para-chlorostyrene, ortho-bromostyrene, meta-bromostyrene, para-bromostyrene, ortho-iodostyrene, meta-iodostyrene, para-iodostyrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, ortho-ethylstyrene, meta-ethylstyrene, para-ethylstyrene, ortho-propylstyrene, meta-propylstyrene, para-propylstyrene, ortho-t-butylstyrene, meta-t-butylstyrene, para-t-butylstyrene and mixtures thereof. ^Claim 3] Sizing composition according to one of claims 1 to 2, characterized in that the hydrophobic monomer A (meth)acrylic acid ester is an unsaturated ethylenic ester resulting from the reaction between (meth)acrylic acid with an alcohol having a. C1 to C30 hydrocarbon group, the hydrocarbon group of the alcohol being able to be saturated or unsaturated, linear, branched or cyclic, optionally substituted by one or more heteroatoms chosen from N, O, P and S, and / or optionally substituted by one or more groups chosen from acid, aryl, ester, amine, amide, carbamate, hydroxyl, ether groups, advantageously C2 and / or C3, nitrile, vinyl, allylic, thioether, sulfonic or halogen.

4. Sizing composition according to one of claims 1 to 3, characterized in that the hydrophobic monomer A vinyl ester has a C1 to C30 hydrocarbon group, the hydrocarbon group being saturated or unsaturated, linear, branched or cyclic, optionally substituted by one or more heteroatoms chosen from N, O, P and S, and / or optionally substituted by one or more groups chosen from acid, aryl, ester, amine, amide, carbamate, hydroxyl, ether, nitrile, vinyl, allylic, thioether, sulfonic or halogen groups.

5. Sizing composition according to one of claims 1 to 4, characterized in that the polymer S2 has a quantity of a monomer B of less than 60 mol%, B being chosen from hydrophilic non-ionic monomers, hydrophilic anionic monomers, hydrophilic cationic monomers, hydrophilic zwitterionic monomers.

6. Sizing composition according to one of claims 1 to 5, characterized in that the polyvinyl amine is obtained by partial or total Hofmann rearrangement of a polymer of acrylamide, methacrylamide, acrylonitrile, or mixtures thereof; or by partial or total hydrolysis of the amide group -N(R2)-C0-Ri of a polymer of a monomer of formula III: [Chem.2] Œ->=CH.—N \ (X)___Rf (ïll) where R1 and R2 are, independently, a hydrogen atom or an alkyl chain of 1 to 6 carbons.

7. Sizing composition according to one of claims 1 to 6, characterized in that the polyvinyl amine has a weight-average molecular weight of between 10,000 g / mol and 1,000,000 g / mol.

8. Sizing composition according to one of claims 1 to 7, characterized in that the polymer and the polyvinyl amine have a weight ratio of between 80 / 20 and 95 / 5.

9. Sizing composition according to one of claims 1 to 8, characterized in that the composition comprises a quantity of starch of between 10 and 80% by weight, relative to the total weight of the sizing composition.

10. A method of sizing paper or cardboard using the sizing composition according to one of claims 1 to 9.

11. Method according to claim 10, characterized in that it is a surface sizing.