Method for manufacturing paper pulp

Abstract

The present invention relates to a method for manufacturing a dry market pulp sheet comprising the addition of a polymeric composition.

Description

[0001] Method for manufacturing paper pulp

[0002] Technical field of the invention

[0003] The present invention relates to a method for manufacturing dry market pulp comprising the addition of a polymeric composition with a cellulosic fiber suspension.

[0004] Prior art

[0005] Dry market pulp is manufactured in paper pulp factories, wherein wood and / or other cellulosic materials are ground to form a cellulosic fiber suspension, also called paper pulp. Paper pulp then undergoes physical and chemical treatments to form dry paper pulp sheets called "dry market pulp". This dry market pulp is the basis of a vast part of paper, cardboard and similar manufacturing methods, wherein it is delivered into an aqueous medium, disintegrated and diluted to form all or some of the thick pulp. Dry market pulp is presented in the form of dried paper pulp sheets. These sheets are generally packaged in balls.

[0006] Generally, the main steps making it possible to form a sheet of paper, cardboard or similar can be as follows:

[0007] - formation of a cellulosic fiber suspension from raw cellulosic material,

[0008] - formation of a fibrous pad by drainage of the cellulosic fiber suspension on a wire,

[0009] - formation of a paper pulp sheet by pressing (dewatering) this fibrous pad,

[0010] - drying of the paper pulp sheet, in order to form the dry market pulp,

[0011] - formation of a thick pulp by dispersion into an aqueous medium of the cellulosic fibers after disintegration and dilution of the dry market pulp,

[0012] - formation of a pulp diluted by dilution of the thick pulp,

[0013] - formation of a sheet of paper, cardboard or similar from the diluted pulp.

[0014] The problems encountered by manufacturers manufacturing this dry market pulp are not the same as those encountered during the formation of paper, cardboard and similar. The treatments of cellulosic raw material in order to obtain this dry market pulp led to constraints and problems that are not found during the formation of a sheet of paper, cardboard and similar.

[0015] One of the greatest problems relates to removing water during the formation of the dry market pulp. Indeed, during the preparation of dry market pulp, the fibrous pad that is formed is much thicker than the fibers mat formed during the draining step in a papermaking process. As a result, removing water is definitely more complicated. Without wishing to be linked to any theory, it seems that the different treatments that the cellulosic fibers undergo during their transformation (from wood and / or other cellulosic materials) into dry market pulp, induce an increased water retention in the fibers at two levels, free water and bound water.

[0016] Free water corresponds to water flowing naturally from the paper pulp during the formation of the fibrous pad. It is possible to accelerate the discharge of free water by physical treatments, like mechanical pressing, in order to obtain a pulp sheet. Indeed, the free water generally represents between 95 and 99% by weight of the water present in the paper pulp fibrous pad.

[0017] The bound water corresponds to the water trapped and retained by the cellulosic fibers in the paper pulp fibrous pad after the drainage step, and that it is found in paper pulp sheets after the pressing step. It is not possible to remove this water by mechanical treatment; it requires a further step of drying at high temperatures to be significantly removed. It generally represents between 30 and 70% by weight of the paper pulp sheet.

[0018] Conventional draining agent used in a papermaking process do not necessarily remove the bound water, especially at pH 6 or more.

[0019] Various additives have been developed to improve water removal in the field of paper pulp manufacture. For instance, documents EP 335576 and US8916026 disclose the combination of a cationic polymer with bentonite. However, these solutions mainly improve the removal of free water without significantly improving the removal of bound water.

[0020] The necessity of further drying implies the consumption of more energy in order to prepare the market pulp.

[0021] This problem does not occur during the formation of a sheet of paper, cardboard and similar, since the drying step of the paper sheet is practically instantaneous upon drying on the rollers, while the thicker paper pulp sheets require more energy to be dried, which results in a higher cost for the manufacturer, but also in a significant negative ecological impact.

[0022] In order to facilitate the removal of this bound water, the drainage step of commercial paper pulp is carried out in acidic conditions. However, acidic conditions result in environmental issues since they require large amounts of hazardous chemicals, and subsequent wastewater treatments prior to be able to release the water back in the nature. The invention aims to replace the use of these hazardous chemicals during the draining step in a dry market pulp manufacturing process. At the same time, the invention does not increase the energy required during the drying step.

[0023] The Applicant has prepared a specific polymeric composition that can address these issues when added to the paper pulp sheets.

[0024] The environmental impact of dry market pulp production is thus reduced and the productivity is improved as the paper pulp sheets require less time to be dried. Furthermore, the addition of the polymeric composition enables a reduction of the quantity of stickies. This polymeric composition also makes it possible to decrease, even remove the yellowing of the cellulosic fibers within the sheet.

[0025] The method according to the invention falls under a principle of environmental awareness and of the impact of industries and man on the planet. The method according to the invention reduces the need for hazardous products as well as the amount of drying energy required for the production or dry market pulp, thus reducing the greenhouse gas emissions, such as the carbon dioxide associated with the manufacture of paper in general.

[0026] The present invention is advantageously carried out using materials of biological origin, such as biomass, or recycled materials. The synthesis of the monomer(s) used in the invention is advantageously a biological synthesis, for example, by enzymatic catalysis or extracted from renewable raw material. The energy used to carry out the method according to the invention is advantageously derived from a heat pump or of renewable origin, for example wind power, photovoltaics, or from fuel cell or lithium battery type.

[0027] Summary of the invention

[0028] The present invention aims for a method for manufacturing a dry market pulp sheet comprising the addition of a polymeric composition before the step of draining a cellulosic fiber aqueous suspension, wherein said polymeric composition is obtained from the polymerization of at least one cationic hydrophilic monomer in the presence of at least one water-soluble polymer selected from the group consisting of poly(dimethylamine- epichlorohydrine), poly(dimethylamine-epichlorohydrine-ethylenediamine), and mixtures thereof. More specifically, the present invention relates to a method for manufacturing a dry market pulp sheet comprising the following steps:

[0029] - preparation of a cellulosic fiber aqueous suspension SAI by pulping raw cellulosic material in the presence of water,

[0030] - addition, to the cellulosic fiber aqueous suspension SAI, of a polymeric composition obtained by polymerization of at least one cationic hydrophilic monomer in the presence of at least one water-soluble polymer selected from the group consisting of poly(dimethylamine- epichlorohydrine), poly(dimethylamine-epichlorohydrine-ethylenediamine) and mixtures thereof, in order to form an aqueous suspension SA2,

[0031] - formation of a fibrous pad having a thickness comprised between 1 mm and 100 mm, by drainage of the aqueous suspension SA2 on a wire at a pH comprised between 6 and 8,

[0032] - formation of a paper pulp sheet by pressing this fibrous pad, and

[0033] - drying of the paper pulp sheet, in order to obtain a dry market pulp.

[0034] The present invention also relates to a dry market pulp, comprising:

[0035] - between 0.001 and 1% by weight of a polymeric composition obtained by polymerization of at least one cationic hydrophilic monomer in the presence of at least one water-soluble polymer selected from the group consisting of poly(dimethylamine-epichlorohydrine), poly(dimethylamine-epichlorohydrine-ethylenediamine) and mixtures thereof;

[0036] - between 79.999 and 99.999% by weight of cellulosic fibers;

[0037] - optionally, between 0.01 and 20% by weight of inorganic particles.

[0038] The dry market pulp according to the invention is generally presented in the form of a sheet.

[0039] Description of the invention

[0040] A "polymer" means a homopolymer prepared from a cationic hydrophilic monomer or a copolymer prepared from at least two different monomers, a cationic hydrophilic monomer and a monomer selected from the group consisting of: anionic hydrophilic monomers, nonionic hydrophilic monomers, zwitterionic hydrophilic monomers, hydrophobic monomers and mixtures thereof. Preferably, these monomers have one CH2=C- function, preferably only one.

[0041] The term "paper" also includes cardboard. "Hydrophilic monomer" means a monomer which has an octanol / water sharing coefficient, Kow, less than or equal to 1, wherein the sharing coefficient Kow is determined at 25 °C in an octanol / water mixture having a volume ratio of 1 / 1, at a pH of between 6 and 8.

[0042] "Hydrophobic monomer" means a monomer which has an octanol / water sharing coefficient, Kow, greater than 1, wherein the sharing coefficient Kow is determined at 25 °C in an octanol / water mixture having a volume ratio 1 / 1, at a pH of between 6 and 8.

[0043] The octanol / water sharing coefficient, KoW, represents the ratio of the concentrations (g / L) of a monomer between the octanol phase and the aqueous phase. It is defined as follows:

[0044] A "water-soluble polymer" means a polymer which gives an aqueous solution without insoluble particle, when it is dissolved under stirring at 25 °C and with a concentration of 10g. I1in deionized water.

[0045] In all of the description, the Brookfield viscosities are measured with a Brookfield viscosimeter, at 25°C in an aqueous solution, with an LV module.

[0046] A person skilled in the art is able to determine the module and the speed of the Brookfield viscosimeter adapted according to the viscosity range to be measured. These types of measures indeed form part of the general knowledge of a person skilled in the art.

[0047] "X and / or Y" mean, according to the invention, "X", or "Y", or "X and Y".

[0048] All the possible combinations between the different embodiments disclosed also form part of the invention, whether these are preferred embodiments, or embodiments given as examples. Furthermore, when the ranges of values are indicated, the limits form part of these ranges. The disclosure also includes all the combinations between the terminals of these ranges of values. For example, the ranges of values "1-20, preferably 5-15", imply the disclosure of the ranges "1-20", "1-5", "1-15", "5-20", and "15-20" and of the values 1, 5, 15 and 20.

[0049] "Raw cellulosic material" means cellulosic fibers coming from cellulosic material(s) that have never undergone a draining step. In other words, the invention is limited to the manufacture of dry market pulp and does not relate to the manufacture of paper sheets, nor the manufacture of dry market pulp from recycled cellulosic fibers. In other terms, the raw cellulosic material has never been dried.

[0050] Method for manufacturing dry market pulp

[0051] Methods for manufacturing dry market pulp are known to a person skilled in the art. For more details on the steps comprised in a method for manufacturing dry market pulp, it can, if necessary, refer to the document, "Pulping Chemistry and Technology" Volume 2 by Ek. Monica (2009).

[0052] A method for manufacturing dry market pulp generally comprises the following steps: a) preparation of a cellulosic fiber aqueous suspension by pulping raw cellulosic material; a') optionally bleaching of the cellulosic fiber aqueous suspension; a") optionally beating of the cellulosic fiber aqueous suspension; b) formation of a fibrous pad by drainage of the cellulosic fiber aqueous suspension of one of the steps a), a') or a"); c) formation of a paper pulp sheet by pressing the fibrous pad; d) drying of the paper pulp sheet in order to obtain the dry market pulp in sheet form.

[0053] The polymeric composition according to the invention can be added to any step of the method before the formation of the fibrous pad (step b)), it can be added to one or more steps. It is preferably added after the step which precedes the step of forming the fibrous pad (step b)), for example, after pulping or after bleaching or after beating.

[0054] The aqueous suspension SAI means the cellulosic fiber aqueous suspension before the addition of the polymeric composition.

[0055] The aqueous suspension SA2 means the cellulosic fiber aqueous suspension which is used to form the fibrous pad, i.e. after the addition of the polymeric composition.

[0056] The quantity of polymeric composition added to the aqueous suspension SAI is advantageously between 0.001 and lOkg / t of dry cellulosic fibers, preferably between 0.002 and 5kg / t, more preferably between 0.005 and Ikg / t.

[0057] In a preferred embodiment, following the addition of the polymeric composition and before the formation of the fibrous pad, the aqueous suspension SA2 is mixed in order to homogenize the cellulosic fiber suspension with the polymeric composition. In a preferred embodiment, the method according to the invention comprises the addition of inorganic particles before the formation of the fibrous pad, i.e. an addition to the aqueous suspension SAI and / or SA2, between the pulping and the formation of the fibrous pad. As inorganic particles, bentonite particles, silica particles, talc particles, aluminium salt particles, and mixtures thereof, can be mentioned in a non-limiting manner. Preferably, these are bentonite or silica particles, more preferably bentonite.

[0058] The quantity of inorganic particles is advantageously comprised between 0.01 and 20kg / t of cellulosic fibers, preferably between 0.05 and 15kg / t, more preferably between 1 and 5kg / t.

[0059] Bentonite is generally used, advantageously, in powder, in slurry form (advantageously 4 to 5% by weight), or in concentrated slurry form (advantageously 13 to 17% by weight). A slurry of bentonite is a mixture of water and bentonite.

[0060] The addition of inorganic particles can be done, once or more times, at any step of the process but before the step of draining the cellulosic fiber suspension. Advantageously they are added once, at the same step as the addition of the polymeric composition.

[0061] The addition of inorganic particles and of the polymeric composition can be done in sequence, i.e. one after the other (the inorganic particles followed by the polymeric composition, or vice versa), at the same time, or in the form of a mixture made beforehand. Preferably, the addition of inorganic particles and of the polymeric composition is done in sequence, the inorganic particles being added before the polymeric composition.

[0062] Pulping of the raw cellulosic material to form a cellulosic fiber suspension

[0063] The raw cellulosic material can come from any types of cellulosic raw material(s) that has not undergone a draining step. One can mention, as an example, and in a non- limiting manner, wood (hardwood and softwood), bamboo, straw, bagasse, or jute. Preferably, the cellulosic raw material comes from wood.

[0064] Pulping can be carried out by any known method. This can be a mechanical, thermomechanical, chemico-thermomechanical, chemical, organosolv pulping, or also a biopulping using fungi or enzymes process. Preferably, this is a chemico-thermomechanical or chemical pulping, more preferably chemical.

[0065] Pulping is carried out in the presence of water. As chemical pulping, the Kraft method, sulfite or alkaline metal carbonate, in particular sodium, or alkaline earth treatment can be mentioned. Preferably, this is the Kraft method.

[0066] Coming from the pulping, the concentration of cellulosic fibers of the cellulosic fiber aqueous suspension is generally at least 1% by weight based on the total weight of the suspension, preferably at least 2% by weight, more preferably at least 3% by weight. Generally, the concentration of the cellulosic fiber aqueous suspension is at most 20% by weight, preferably at most 15% by weight, more preferably at most 10% by weight.

[0067] Bleaching of the cellulosic fiber aqueous suspension

[0068] According to an embodiment, the cellulosic fiber aqueous suspension can be bleached by a chemical treatment.

[0069] The bleaching is generally composed of several successive distinct steps, comprising the addition of chemical compounds. These steps form part of the general knowledge of a person skilled in the art, who can consult the document, "Pulping Chemistry and Technology", if needed.

[0070] Following the bleaching step, the cellulosic fiber suspension can form the subject of a washing step, in order to remove the undissolved impurities and / or remove the products used during the bleaching steps, but also the possible residues from these products.

[0071] Beating of the cellulosic fiber suspension

[0072] The terms "beating" and "refining" are used interchangeably. They make reference to the mechanical treatment of the cellulosic fiber suspension to make it capable for the subsequent manufacture of paper. Following a chemico-thermomechanical or chemical pulping, the cellulosic fiber suspension is practically never transformed into dry market pulp without having been subjected to beating beforehand. The beating is an important step of the method, as the paper pulp has no paper property as it has not been modified by mechanical treatment. The effects of the beating on the fibers are mainly split into five parts: movement and deformation of the cell walls, breaking of the primary and secondary walls, swelling of the water, fibrillation and transverse cutting. According to the conditions of the beating, it is possible to change the physical properties of the paper pulp which makes it possible to obtain, during the subsequent manufacture of the paper sheet, sheets with different physical properties, which are then used for different applications. A notable effect of the beating is the decrease of the drainability of the cellulosic fiber suspension, as it tends to make the fibers more difficult to dehydrate, it is particularly interesting to use the polymeric composition of the invention for cellulosic fiber suspensions having undergone a beating step. Thus, in a preferred embodiment, the method for manufacturing dry market pulp comprises a step of beating the cellulosic fiber suspension.

[0073] Formation of dry market pulp

[0074] The fibrous pad has a thickness comprised between 1 mm and 100 mm, preferably between 2 mm and 50 mm, more preferably between 3 mm and 30 mm.

[0075] The formation of the fibrous pad is made at a pH comprised between 6 and 8, preferably between 6.5 and 7.5, more preferably between 6.7 and 7.3.

[0076] The steps of draining, pressing and drying the paper pulp sheet are conventional and are part of the general knowledge of a person skilled in the art.

[0077] Advantageously, the weight of cellulosic fibers of the dry market pulp sheet is between 250 and 5000 g / m2, preferably between 280 and 4000 g / m2, more preferably between 300 and 3000 g / m2.

[0078] Polymeric composition

[0079] The polymeric composition is obtained from the polymerization of at least one cationic hydrophilic monomer in the presence of at least one water-soluble polymer selected from the group consisting of poly(dimethylamine-epichlorohydrine), a poly(dimethylamine- epichlorohydrine-ethylenediamine) and mixtures thereof.

[0080] In the rest of the description, the water-soluble polymer is called "host polymer".

[0081] Polymeric composition - Host polymer

[0082] The host polymer is a polyamine having at pH 7, ammonium groups and hydroxyl (-OH) groups.

[0083] The host polymer can be obtained according to any polymerization technique. Preferably, it is obtained by polymerization in solution. The host polymer is a polyamine selected from the group consisting of: a poly(dimethylamine-epichlorohydrine), a poly(dimethylamine-epichlorohydrine- ethylenediamine) and mixtures thereof.

[0084] In a preferred embodiment, the host polymer is poly(dimethylamine-epichlorohydrine- ethylenediamine). This polymer is obtained by the reaction between dimethylamine, ethylenediamine and epichlorohydrine.

[0085] In an embodiment, the host polymer can be structured by a branching agent.

[0086] When the host polymer comprises a branching agent, the polymer remains soluble in water. The host polymer can also be prepared in the presence of a transfer agent. A person skilled in the art will know how to adjust the quantity of branching agent, and optionally the quantity of transfer agent in order to arrive at this result.

[0087] In a preferred embodiment, the host polymer is free of branching agent.

[0088] In an embodiment, the host polymer comprises a transfer agent.

[0089] In an embodiment, the host polymer is free of transfer agent.

[0090] The host polymer advantageously has a molecular weight of at least 1000 g / mol, preferably of at least 2000 g / mol, and even more preferably, of at least 5000 g / mol. Generally, the molecular weight of the host polymer is advantageously less than 2 million g / mol, more advantageously, less than 1 million g / mol.

[0091] The average molecular weight by weight is preferably measured by gel permeation chromatography coupled with a Malls detector. This is the average molecular weight by weight.

[0092] Composition of the polymeric composition

[0093] The polymeric composition is obtained from the polymerization of at least one cationic hydrophilic monomer in the presence of a host polymer selected from the group consisting of: a poly(dimethylamine-epichlorohydrine), a poly(dimethylamine-epichlorohydrine- ethylenediamine) and mixtures thereof. The at least cationic hydrophilic monomer is advantageously selected from vinyl-type monomers, in particular acrylamide derivatives, acrylic derivatives, allylic derivatives or maleic derivatives having a protonable amine function or an ammonium group, advantageously a quaternary ammonium group. Preferably, the at least cationic hydrophilic monomer is selected from the group consisting of: diallyldialkyl ammonium salts like dimethyldiallylammonium chloride (DADMAC); acidified or quatemized dialkyl- aminoalkyl(meth)acrylamide salts, like for example (3- methacrylamidopropyl)trimethylammonium chloride (MAPTAC), (3- acrylamidopropyl)trimethylammonium chloride (APTAC); acidified or quatemized dialkylaminoalkyl acrylate salts like quatemized or salified dimethylaminoethyl acrylate (DMAEA); acidified or quatemized dialkyl aminoalkyl methacrylate salts like quatemized or salified dimethylaminoethyl methacrylate (DMAEMA); acidified or quatemized N,N- dimethylallylamine salts; acidified or quatemized diallylmethylamine salts; acidified or quatemized diallylamine salts; vinylamine obtained by hydrolysis (basic or acid) of an amide group -N(R2)-CO-R1with R1and R2being, independently, a hydrogen atom or an alkyl chain of 1 to 6 carbons, for example vinylamine coming from the hydrolysis of vinylformamide; vinylamine obtained by Hofmann degradation; and mixtures thereof can be mentioned. Advantageously, the alkyl groups are C1-C7, preferably C1-C3 and can be linear, cyclic, saturated or unsaturated chains. Preferably, the cationic hydrophilic monomer is selected from the group consisting of quatemized or salified dimethylaminoethyl acrylate (DMAEA), quatemized or salified dimethylaminoethyl methacrylate (DMAEMA), and mixtures thereof. More preferably, it is quatemized or salified dimethylaminoethyl acrylate (DMAEA).

[0094] The quantity of polymerized cationic hydrophilic monomer is advantageously comprised between 1 and 80 mol% based on the total molar quantity of polymerized monomers, preferably between 2 and 60 mol%, more preferably between 5 and 40 mol%.

[0095] The skilled person in the art will know how to prepare quatemized monomers, for example by means of an R-X-type quatemization agent, R being an alkyl group and X being a halogen or a sulphate.

[0096] A "quatemization agent" means a molecule being able to alkylate a tertiary amine.

[0097] The quatemization agent can be selected from dialkyl sulphates comprising 1 to 6 carbon atoms or alkyl halides comprising 1 to 6 carbon atoms. Preferably, the quatemization agent is selected from the group consisting of methyl chloride, benzyl chloride, dimethyl sulphate, diethyl sulphate, and mixtures thereof.

[0098] Furthermore, the present invention also covers DADMAC-, APTAC- and MAPTAC-type monomers, the counter-ion of which is a sulphate, a fluoride, a bromide or an iodide instead of chloride.

[0099] The at least one cationic hydrophilic monomer can be polymerized in the presence of one or more hydrophilic monomers selected from the group consisting of: non-ionic hydrophilic monomer, anionic hydrophilic monomer, zwitterionic hydrophilic monomer, and mixtures thereof.

[0100] In addition to the at least cationic hydrophilic monomer, the preparation of the polymeric composition can involve the polymerization of at least one monomer selected from the group consisting of: non-ionic hydrophilic monomer, anionic hydrophilic monomer, zwitterionic hydrophilic monomer, and mixtures thereof.

[0101] Advantageously, the non-ionic hydrophilic monomer(s) used in the invention are selected from the group consisting of: acrylamide, methacrylamide, N-alkylacrylamides, N- alkylmethacrylamides, N,N-dialkyl acrylamides (for example, N,N-dimethylacrylamide or N,N-diethylacrylamide), N,N-dialkylmethacrylamides, acrylic acid alkoxyl esters, methacrylic acid alkoxyl esters, N-vinylpyrrolidone, N-methylol(meth)acrylamide, N-vinyl caprolactame, N-vinylformamide (NVF), N-vinyl acetamide, N-vinyl imidazole, N-vinyl succinimide, acryloyl morpholine (ACMO), glycidyl methacrylate, vinyl acetate, glyceryl methacrylate, diaketone acrylamide, methacrylic anyhydride, acrylonitrile, maleic anydride, itaconic anhydride, itaconamide, hydroxyalkyl (meth)acrylate, thioalkyl (meth)acrylate, isoprenol and its alcoxyl derivatives, hydroxyethyl(meth)acrylates and their alcoxyl derivatives, hydroxypropyl(meth)acrylate and its alcoxyl derivatives, and mixtures thereof. Among these non-ionic monomers, the alkyl groups are advantageously C1-C5, more advantageously, C1-C3. Preferably, the non-ionic hydrophilic monomer is acrylamide.

[0102] The quantity of polymerized non-ionic hydrophilic monomer is advantageously comprised between 20 and 99 mol% based on the total molar quantity of polymerized monomers, preferably between 40 and 98 mol%, more preferably between 60 and 95 mol%. Advantageously, the anionic hydrophilic monomer(s) used in the invention are selected from monomers having a vinyl function, in particular, acrylic, sulfonic, maleic, fumaric, itaconic, or allylic. They can also contain a carboxylate, phosphonate, phosphate, sulfonate, sulphate group, or another anionic charge group. Preferred monomers belonging to this class are, for example, acrylic acid; methacrylic acid; dimethylacrylic acid; itaconic acid; C1-C3 itaconic acid hemi-esters; acryloyl chloride; crotonic acid; maleic acid; fumaric acid; 3-acrylamido 3- methylbutanoic acid; strong acid-type monomers having, for example, a sulphonic acid- or phosphonic acid-type function, such as vinylsulphonic acid, vinylphosphonic acid, allylsulphonic acid, methallylsulphonic acid, 2-methylidenepropane-l,3-disulphonic acid, 2- sulfoethylmethacrylate, sulfopropylmethacrylate, sulfopropylacrylate, allylphosphonic acid, ethylene glycol methacrylate phosphate, sulphonic styrene acid, 2-acrylamido-2- methylpropane sulphonic acid (ATBS), 2-acrylamido-2-methylpropane disulphonic acid, 3- allyloxy-2-hydroxypropane sulphonic acid, diethylallylphosphonate, carboxyethyl acrylate; water-soluble salts of these monomers, like their alkaline metal salts, alkaline earth metals, or ammonium; and mixtures thereof. Preferably, the anionic hydrophilic monomer is acrylic acid or a salt thereof.

[0103] The quantity of polymerized anionic hydrophilic monomer is advantageously comprised between 0 and 80 mol% based on the total molar quantity of polymerized monomers, preferably between 1 and 60 mol%, more preferably between 2 and 40 mol%.

[0104] In an embodiment, the anionic hydrophilic monomer(s) can be partially or totally salified.

[0105] By “salified”, is meant the substitution of a proton of at least one acid function of the - Ra(=O)-OH type (with Rarepresenting P, S or C) of the anionic monomer by a metal or ammonium cation to form a salt of the -Ra(=O)-OX type (X being a metal cation or an 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, while the salified form of the monomer corresponds to the Rb-C(=O)-O“ X+form, X+corresponding to an alkaline cation or an organic cation. The salification of the acid functions can be partial or total.

[0106] The salified form advantageously corresponds to the alkaline metal salts (Li, Na, K, etc.), alkaline earth metal salts (Ca, Mg, etc.) or ammonium salts (for example, ammonium ion or a tertiary ammonium), or mixtures thereof. The preferred salts are sodium salts.

[0107] The salification can be done, partially or totally, before, during or after polymerization. In an embodiment, between 1 and 100 mol% of the anionic hydrophilic monomers are in salified form, preferably between 10 and 90 mol%.

[0108] Advantageously, the zwitterionic hydrophilic monomers used are selected from derivatives of a vinyl-type pattern (advantageously acrylamide, acrylic, allylic or maleic).

[0109] Preferably, this monomer comprises an amine or ammonium function (for example, quaternary ammonium) and a carboxylic (or carboxylate)-, sulphonic (or sulfonate)- or phosphoric (or phosphate)-type acid function.

[0110] The zwitterionic hydrophilic monomers are advantageously selected from the group consisting of dimethylaminoethyl acrylate derivatives can be mentioned, such as 2 - ((2-9 (acryloyloxy) ethyl) dimethylammonio) ethane- 1 -sulfonate, 3 - ((2- (acryloyloxy) ethyl) dimethylammonio) propane- 1 -sulfonate, 4 - ((2- (acryloyloxy) ethyl) dimethylammonio) butane- 1 -sulfonate, [2- (acryloyloxy) ethyl] (dimethylammonio) acetate, derivatives of dimethylaminoethyl methacrylate such as 2 - ((2- (methacryloyloxy) ethyl) dimethylammonio) ethane- 1 -sulfonate, 3 - ((2- (methacryloyloxy) ethyl) dimethylammonio) propane- 1 -sulfonate, 4 - ((2 - (methacryloyloxy) ethyl) dimethylammonio) butane- 1- sulfonate, [2- (methacryloyloxy) ethyl] (dimethylammonio) acetate, derivatives of dimethylamino propylacrylamide such as 2 - ((3-acrylamidopropyl) dimethylammonio) ethane- 1- sulfonate, 3 - ((3-acrylamidopropyl) dimethylammonio) propane- 1 -sulfonate, 4 - ((3-acrylamidopropyl) dimethylammonio) butane- 1 -sulfonate, [3- (acryloyl) oxy) propyl] (dimethylammonio) acetate, dimethylamino propyl methylacrylamide, or also derivatives such as 2 - ((3 -methacryl amidopropyl) dimethylammonio) ethane- 1 -sulfonate, 3 - (dimethylammonio) propane- 1 -sulfonate 4 - ((3 -methacrylamidopropyl) dimethylammonio) butane- 1 -sulfonate and propyl [3- (methacryloyloxy)] (dimethylammonio) acetate and mixtures thereof.

[0111] Other zwitterionic hydrophilic monomers can be used, in particular those described by the Applicant in document WO2021 / 123599.

[0112] The quantity of polymerized zwitterionic hydrophilic monomer is advantageously less than 30 mol% based on the total molar quantity of polymerized monomers, preferably less than 10 mol%. In a preferred embodiment, the polymeric composition is free of zwitterionic hydrophilic monomers.

[0113] In an embodiment, the polymerization of the polymeric composition may involve one or more hydrophobic monomers.

[0114] Advantageously the monomer(s) having a hydrophobic character used are selected from the group consisting of (meth)acrylic acid esters having a (i) C4-C30 alkyl chain or (ii) arylalkyl (C4-C30 alkyl, C4-C30 aryl), or (iii) propoxylated, or (iv) ethoxylated, or (v) ethoxylated and propoxylated; the alkyl aryl sulfonates (C4-C30 alkyl, C4-C30 aryl); the mono- or di-substituted (meth)acrylamide amides having a (i) C4-C30 alkyl chain, or (ii) arylalkyl (C4-C30 alkyl, C4- C30 aryl), or (iii) propoxylated, or (iv) ethoxylated, or (v) ethoxylated and propoxylated; anionic or cationic (meth)acrylamide or (meth)acrylic acid monomer derivatives carrying a hydrophobic chain; and mixtures thereof. Hydrophobic monomers can comprise halogen atoms, for example, chlorine.

[0115] Among these hydrophobic monomers:

[0116] - the alkyl groups are preferably C4-C20, more preferably C4-C8. The C6-C20 alkyls are preferably linear alkyls, while the C4-C5 alkyls are preferably branched,

[0117] - the arylalkyl groups are preferably C7-C25, more preferably C7-C15,

[0118] - the ethoxylated chains advantageously comprise between 1 and 200 -CH2-CH2-O- groups, preferably between 6 and 100, more preferably between 10 and 40,

[0119] - the propoxylated chains advantageously comprise between 1 and 50 -CH2-CH2-CH2-O- groups, more preferably between 1 and 20.

[0120] Preferred hydrophobic monomers belonging to these classes are, for example:

[0121] - n-hexyl (meth)acrylate, n-octyl (meth)acrylate, oxtyl (meth)acrylamide, lauryl (meth)acrylate, lauryl (meth)acrylamide, myristyl (meth)acrylate, myristyl (meth)acrylamide, pentadecyl (meth)acrylate, pentadecyl (meth)acrylamide, cetyl (meth)acrylate, cetyl (meth)acrylamide, oleyl (meth)acrylate, oleyl (meth)acrylamide, erucyl (meth)acrylate, erucyl (meth)acrylamide, N-tert-Butyl(meth)acrylamide, vinylpyridine, 2-ethylhexyle acrylate, C4- C22 itaconic acid hemi-esters, C4-C22 acidified or quatemized dialkyl aminoalkyl (meth)acrylate salts, C4-C22 acidified or quatemized dialkyl aminoalkyl (meth)acrylamide salts, undecanoic acrylamido acid, and mixtures thereof,

[0122] - the allyl cationic derivatives of formula (I) or (II):

[0123] 0) (II) wherein:

[0124] R: independently an alkyl chain containing 1 to 4 carbons;

[0125] Ri: an alkyl or arylalkyl chain containing 8 to 30 carbons; X: a halide selected from the group consisting of bromides, chlorides, iodides, fluorides, and any negatively charged counter-ion; and, preferably, hydrophobic cationic derivatives of the (meth)acryloyl type responding to the formula (III): wherein:

[0126] - A represents O or N-R5 (preferably A represents N-R5),

[0127] - R2, R3, R4, Rs, Re, R7: independently a hydrogen atom or an alkyl chain containing 1 to 4 carbons (R2 and R3 are preferably hydrogen atoms),

[0128] - Q: an alkyl chain containing 1 to 20 carbons, - Rs: an alkyl or arylalkyl chain containing 8 to 30 carbons,

[0129] - X: a halide selected from the group consisting of bromides, chlorides, iodides, fluorides, and of any negatively charged counter-ion. The polymeric composition advantageously comprises less than 3mol% of hydrophobic monomers.

[0130] When the polymeric composition comprises hydrophobic monomer, they are present in a quantity such that the polymeric composition remains soluble in water.

[0131] In a preferred embodiment, the polymeric composition is free of hydrophobic monomers.

[0132] The quantities of the different monomers will be adjusted by the skilled person in the art, in order to not exceed 100 mol% during the preparation of the polymeric composition.

[0133] In a preferred embodiment, the polymeric composition is obtained from the polymerization of at least two distinct types of hydrophilic monomers, at least one cationic hydrophilic monomer and advantageously at least one non-ionic hydrophilic monomer, in the presence of at least one water-soluble polymer selected from poly(dimethylamine-epichlorohydrine), poly(dimethylamine-epichlorohydrine-ethylenediamine) and mixtures thereof. Preferably, the polymeric composition is obtained from the polymerization of a cationic hydrophilic monomer (for example, quatemized DMAEA with methyl chloride) and acrylamide.

[0134] The mass ratio between the hydrophilic monomers (optionally hydrophobic) and the host polymer is advantageously between 99 / 1 and 1 / 99, preferably between 95 / 5 and 40 / 60.

[0135] Obtaining the polymeric composition

[0136] The polymeric composition is obtained by polymerization of at least one cationic hydrophilic monomer in the presence of at least one water-soluble polymer selected from poly(dimethylamine-epichlorohydrine), poly(dimethylamine-epichlorohydrine- ethylenediamine) and mixture thereof. Optionally, the polymerization is carried out in the presence of at least one branching agent and / or at least one transfer agent.

[0137] The optional branching agent and the optional transfer agent are different from the host polymer. They are also different from the monomers that are polymerized in the presence of the host polymer in order to prepare the polymeric composition.

[0138] The branching agent is advantageously selected from the group consisting of:

[0139] - structure agents, being selected from the group consisting of polyethylenic unsaturation compounds (having, as a minimum, two unsaturated functions) different from the cationic hydrophilic monomer(s), like for example vinyl functions, in particular allylic or acrylic, and for example, methylene bis acrylamide (MBA), triallyamine, tetraallylammonium chloride or 1,2 dihydroxyethylene bis-(N-acrylamide),

[0140] - compounds having at least two epoxy functions,

[0141] - compounds having at least one unsaturated function and one epoxy function,

[0142] - macroinitiators such as polyperoxides, polyazoics and polyols,

[0143] - functionalized polysaccharides,

[0144] - water-soluble metal complexes composed of:

[0145] * a valence metal greater than or equal to 3, such as, as an example and in a non-limiting manner, aluminum, boron, zirconium or also titanium, and

[0146] * a ligand carrying a hydroxyl function can be mentioned.

[0147] The quantity of branching agent is advantageously comprised between 0 and 1000 ppm, based on the total weight of the monomers used during the preparation of the polymeric composition, more preferably, between 1 and 500 ppm.

[0148] When the polymeric composition comprises the implementation of a branching agent, the polymeric composition remains soluble in water. A person skilled in the art will know how to adjust the quantity of branching agent, and optionally the quantity of transfer agent in order to arrive at this result.

[0149] In an embodiment, the polymeric composition does not comprise the implementation of branching agent during polymerization.

[0150] The transfer agent is advantageously selected from the group consisting of: methanol; isopropyl alcohol; sodium hypophosphite; calcium hypophosphite; magnesium hypophosphite; potassium hypophosphite; ammonium hypophosphite; formic acid; sodium formiate; calcium formiate; magnesium formiate; potassium formiate; ammonium formiate; 2 -mercaptoethanol; 3 -mercaptopropanol; glycol dithiopropylene; thioglycerol; thioglycol acid; thiohydracrylic acid; thiolactic acid; thiomalic acid; cysteine; aminoethanethiol; thioglycolates; allyl phosphites; allyl mercaptans, like n-dodecyl mercaptan; sodium methallysulfonate; calcium methallysulfonate; magnesium methallysulfonate; potassium methallysulfonate; ammonium methallysulfonate; alkyl phosphites like tri alkyl (C12-C15) phosphites, di-oleyl-hydrogenophosphites, dibutyl phosphite; dialkyldithiophosphates like dioctyl phosphonate; tertiary nonylmercaptan; 2-ethylhexyl thioglycolate; n-octyl mercaptan; n-dodecyl mercaptan; tertio-dodecyl mercaptan; iso-octylthioglycolate; 2-ethylhexyl thioglycolate; 2-ethylhexyl mercaptoacetate; polythiols; and mixtures thereof. Preferably, this is sodium hypophosphite or sodium formiate.

[0151] In an embodiment, the transfer agent is a polytransfer agent, such as a polymercaptan polymer.

[0152] The quantity of transfer agent is advantageously comprised between 0 and 1000 ppm, based on the total weight of the monomers used during the preparation of the polymeric composition, more preferably between 1 and 500 ppm.

[0153] In a preferred embodiment, the water-soluble polymer plays the role of a transfer agent. Thus, the polymerization of at least one cationic hydrophilic monomer can be carried out in the absence of non-polymeric transfer agent. Advantageously, the molecular weight of a non- polymeric transfer agent is less than 200 g / mol.

[0154] In an embodiment, the preparation of the polymeric composition is free of transfer agent.

[0155] In a preferred embodiment, the at least cationic hydrophilic monomer or a monomer constituting the water-soluble polymer originates from a feedstock comprising at least partially renewable and non-fossil origin.

[0156] In the context of the invention, the terms “of renewable and non-fossil origin” designate the origin of a chemical compound issuing from biomass or synthetic gas (syngas), namely, one that is the result of one or more chemical transformations performed on one or more raw materials of natural, and non-fossil, origin. The terms “bio-sourced” or “bio-resourced” can also be used to characterize the renewable and non-fossil origin of a chemical compound. The renewable and non-fossil origin of a compound includes renewable and non-fossil raw materials coming from the circular economy, and which have been previously recycled, one or more times, during a recycling process of material coming from biomass, such as, for example, material coming from polymer depolymerization or from the transformation of pyrolysis oil.

[0157] According to the invention, “at least partially of renewable and non-fossil origin” means a content of bio-sourced carbon comprised between 5% by weight and 100% by weight based on to the total carbon weight of said compound, preferably at least 30%, more preferably at least 50%, even more preferably at least 70%, more preferably at least 90% and even more preferably 100% bio-sourced carbon.

[0158] In the context of the invention, the standard ASTM D6866-21, method B, is used to characterize the bio-sourced nature of a chemical compound, and to determine the bio-sourced content of said compound. The value is expressed in percent by weight of bio-sourced carbon based on to the total weight of carbon in said compound.

[0159] The ASTM D6866-21 standard is a test method that teaches how to experimentally measure the bio-sourced carbon content of solids, liquids and gaseous samples by radiocarbon analysis.

[0160] This standard primarily uses Accelerator Mass Spectrometry (AMS) technology. This technique is used to naturally measure the radionuclides present in a sample, wherein the atoms are ionized, then accelerated to high energies, then separated, and individually counted in Faraday cups. This high-energy separation is extremely effective at filtering out isobaric interference, so that AMS is able to accurately measure abundances of carbon- 14 relative to carbon-12 (14C / 12C) to an accuracy of 1.1015.

[0161] The ASTM D6866-21 standard Method B uses AMS and IRMS (Isotope Ratio Mass Spectroscopy). The test method allows to directly differentiate contemporary carbon-based carbon atoms from fossil-based carbon atoms. A measure of the carbon- 14 to carbon- 12 or carbon- 14 to carbon- 13 content of a product is determined against a modem carbon-based reference material accepted by the radiocarbon dating community such as the NIST’s Standard Reference Material (SRM) 4990C (oxalic acid).

[0162] The sample preparation method is described in the standard and does not require any special comment as it is a commonly used procedure.

[0163] Analysis, interpretation and reporting of results are described below. Isotope ratios of carbon- 14 to carbon- 12 content or carbon- 14 to carbon- 13 content are measured using AMS. Isotope ratios of carbon- 14 to carbon- 12 content or carbon- 14 to carbon- 13 content are determined relative to a standard traceable via the NIST SRM 4990C modem reference standard. The “fraction of modem” (fM) represents the amount of carbon- 14 in the tested product relative to the modem standard. It is most often referred to as percent modem carbon (pMC), the percentage equivalent to fM (e.g. fM 1 = 100 pMC). All pMC values obtained from radiocarbon analyses must be corrected for isotopic fractionation using a given stable isotope. The correction should be made using the carbon- 14 to carbon- 13 values determined directly using the AMS where possible. If this is not possible, the correction should be made using the delta 13C (813(2) measured by IRMS, CRDS (Cavity Ring Down Spectroscopy) or any other equivalent technology that can provide accuracy to within plus or minus 0.3 per thousand.

[0164] “Zero pMC” represents the total absence of measurable 14C in a material above the background signals, thus indicating a fossil (e.g. petroleum-based) carbon source. A value of 100 pMC indicates a fully “modem” carbon source. A pMC value between 0 and 100 indicates a proportion of carbon derived from a fossil source relative to a “modem” source.

[0165] The pMC may be higher than 100% due to the persistent, but diminishing, effects of 14C injection into the atmosphere caused by atmospheric nuclear testing programmes. The pMC values need to be adjusted by an atmospheric correction factor (REF) to obtain the actual biosourced content of the sample.

[0166] The correction factor is based on the excess 14C activity in the atmosphere at the time of testing. A REF value of 102 pMC was determined for 2015 based on CO2 measurements in the air in a mral area of the Netherlands (Lutjewad, Groningen). The first version of this standard (ASTM D6866-04) in 2004 had referenced a value of 107.5 pMC, while the later version ASTM D6866-10 (2010) had referenced a value of 105 pMC. These data points represent a drop of 0.5 pMC per year. Consequently, on 2 January of each year, the values in Table 1 below were used as REF value until 2019, reflecting the same decrease of 0.5 pMC per year. The REF values (pMC) for 2020 and 2021 have been determined to be 100.0 based on continuous measurements in the Netherlands (Lutjewad, Groningen) until 2019. References for reporting carbon isotope ratio data are provided below for 14C and 13C, respectively Roessler, N., Valenta, R. J., and van Cauter, S., “Time-resolved Liquid Scintillation Counting”, Liquid Scintillation Counting and Organic Scintillators, Ross, H., Noakes, J. E., and Spaulding, J. D., Eds., Lewis Publishers, Chelsea, MI, 1991, pp. 501-511. Allison, C. E., Francy, R. J., and Meijer, H. A. J., “Reference and Intercomparison Materials for Stable Isotopes of Light Elements”, International Atomic Energy Agency, Vienna, Austria, IAEATECHDOC- 825, 1995. The percentage of the bio-sourced carbon content is calculated by dividing pMC by REF and multiplying the result by 100. For example, [102 (pMC) / 102 (REF)] x 100 = 100% biosourced carbon. The results are indicated as a weight percentage (wt%) of bio-sourced carbon relative to the total carbon weight in said compound.

[0167] Table 1 : Reference of percentage of modem carbon (pMC)

[0168] In a particularly preferred embodiment, 100 wt% of the carbon in the polymeric composition originates from a feedstock comprising recycled material or materials of biological origin, the biobased carbon content is measured in accordance with ASTM D6866-21, Method B.

[0169] Preparation of the polymeric composition

[0170] Generally, the polymeric composition can be obtained according to any polymerization techniques well-known by a person skilled in the art. In particular, this can be obtained by a polymerization in solution: polymerization in gel; polymerization by precipitation; polymerization in emulsion (aqueous or inverted); polymerization in suspension; polymerization by reactive extrusion; water-in-water polymerization; or micellar polymerization. Preferably, the polymerization is an inverted polymerization in emulsion or a water-in-water polymerization. More preferably, this is an inverted polymerization in emulsion.

[0171] The polymerization is generally a free radical-controlled radical polymerization. By free radical polymerization, free radical polymerization by means of UV, azoic, redox or thermal initiators are included, as well as controlled radical polymerization (CRP) techniques or on- matrix polymerization techniques. Preparation of the polymeric composition - Inverted emulsion

[0172] The expression "inverted emulsion" means both inverted emulsions and inverted microemulsions. These are water-in-oil-type emulsions, wherein the aqueous phase is dispersed in the lipophilic phase in the form of drops or droplets.

[0173] An inverted emulsion consists of a two-phase medium. It can be unstable in the absence of surfactant (the surfactants group gather water-in-oil-type emulsifying agents and oil-in-water emulsifying agents). Under stirring, hydrophilic phase particles are observed, dispersed in a lipophilic phase, having a wide size distribution around an average which can be around one micrometer. During an inverted emulsion polymerization, the monomer is dispersed in large droplets of the emulsion (diameter: around 50nm to 10pm), as well as in small emulsifying micelles (diameter: around 5 to lOnm).

[0174] This polymerization technique is well-known to a person skilled in the art. It consists of putting a hydrophilic phase in emulsion comprising one or more monomers in a lipophilic phase. This emulsification is done thanks to a water-in-oil emulsifying agent.

[0175] An inverted emulsion generally comprises at least:

[0176] - a hydrophilic phase comprising at least one hydrophilic monomer;

[0177] - a lipophilic phase;

[0178] - at least one water-in-oil emulsifying agent;

[0179] - optionally, an oil-in-water emulsifying agent.

[0180] A "water-in-oil emulsifying agent" means a compound capable of emulsifying water in an oil and an "oil-in-water emulsifying agent" is a compound capable of emulsifying an oil in water. Generally, it is considered that an emulsifying agent of the water-in-oil type is a surfactant having an HLB strictly less than 8, and that an oil-in-water emulsifying agent is a surfactant having an HLB greater than or equal to 10. A surfactant having an HLB of between 8 and 10 is considered as a wetting agent. A person skilled in the art can refer to the document, "Handbook of Applied Surface and Colloid Chemistry" by K.Holmberg, Chapter 11, if needed.

[0181] The hydrophilic-lipophilic balance (HLB) of a chemical compound is a measurement of its hydrophilic and / or lipophilic properties, determined by calculating the values for the different regions of the molecule, such as described by Griffin in 1949. In the present invention, the Griffin method has been adopted, based on calculating a value based on the chemical groups of the molecule. Griffin has attributed a dimensionless number between 0 and 20 to give information on the solubility of water and oil.

[0182] The HLB value of a substance having a total molecular mass M and a hydrophilic part of a molecular mass Mh is given by:

[0183] HLB = 20 (Mh / M).

[0184] The hydrophilic phase of the emulsion is advantageously water.

[0185] The lipophilic phase of the emulsion can be a mineral oil, a vegetable oil, a synthetic oil or a mixture of several of these oils.

[0186] Examples of mineral oil are mineral oils containing saturated or unsaturated hydrocarbons of the aliphatic-, naphtenic-, paraffin-, isoparaffin-, cycloparaffin- or naphtyl-type.

[0187] Examples of vegetable oils are squalene, an ester- or triglyceride -type oil, like coco caprylate / caprate, octyldodecyl myristate, ethoxylated vegetable oils, jojoba oil, macadamia oil.

[0188] Examples of synthetic oil are hydrogenated polydecene or hydrogenated polyisobutene, esters such as oxtyl stearate or butyl oleate. The range of Exxsol® products from ExxonMobil are perfectly suitable.

[0189] The water-in-oil emulsifying agent is advantageously selected from the group consisting of: polyesters having a molecular weight of between 1000 and 3000g / mol; condensation products between a succinic poly(isobutenyl) acid or its anhydride and a glycol polyethylene; sequenced block polymers having a molecular weight of between 2500 and 3500g / mol, like for example those sold under Hypermer® names; sorbitan extracts, such as monooleate or sorbitan polyoleates, polyethoxylated sorbitan esters; diethyoxyl oleocetylic alcohol; tetraethoxyl laurylacrylate; fatty alcohol condensation products greater than ethylene, like an oleic alcohol reaction product with 2 ethylene oxide units; alkylphenol and ethylene oxide condensation products, such as the nonyl phenol reaction product with 4 ethylene oxide units. Ethoxyl fatty amines such as Witcamide® 511, alkyl phosphate esters, betaine-based products and ethoxyl amine are also good candidates as emulsifying agents of the water-in-oil type. The quantity of water-in-oil emulsifying agent in the inverted emulsion is advantageously between 0.5 and 10% by weight based on the total weight of the inverted emulsion, preferably between 1 and 6% by weight, more preferably between 2 and 4% by weight.

[0190] The method of the invention can comprise the addition of at least one oil-in-water emulsifying agent.

[0191] The oil-in-water emulsifying agent(s) are advantageously selected from the group consisting of ethoxylated nonylphenol, preferably having 4 to 10 ethoxylations (i.e. preferably having an ethoxylation degree going from 4 to 10); ethoxylated / propoxylated alcohols preferably having an ethoxylation / propoxylation comprising 12 to 25 carbon atoms; ethoxylated tridecyl alcohols; ethoxylated / propoxylated fatty alcohols; ethoxylated sorbitan esters (advantageously having 20 ethylene oxide molar equivalents); polyethoxylated sorbitan laurate (advantageously having 20 ethylene oxide molar equivalents); polyethoxylated castor oil (advantageously having 40 ethylene oxide molar equivalents); decaethoxylated oleodecyclic alcohol; hepta oxyethylated lauric alcohol; polyethoxylated sorbitan monostearate (advantageously having 20 ethylene oxide molar equivalents); cetyl ether polyethoxylated phenol alkyls (advantageously having 10 ethylene oxide molar equivalents); aryl ether alkyl ethylene polyoxides; N-cetyl-N-ethyl morpholinium ethosulfate; sodium sulfate lauryl; fatty alcohol condensation products with ethylene oxide (advantageously having 10 ethylene oxide molar equivalents); alkylphenol and ethylene oxide condensation products (advantageously having 12 oxide ethylene molar equivalents); fatty amine condensation products with 5 molar equivalent or more ethylene oxide (advantageously 5 to 50 equivalents); ethoxylated phenol tristyryl, condensates of ethylene oxide with partially esterified polyhydric alcohols with fatty chains, as well as their anhydrous forms; amine oxides advantageously having alkyl polyglucosides; glucamide; phosphate esters; sulphonic alkylbenzene acids and their salts; and surfactant block polymers and mixtures thereof. The alkyl groups of these oil-in-water- type emulsifying agents mean linear or branched groups and advantageously having 1 to 20 carbon atoms, more advantageously 3 to 15 carbon atoms. Furthermore, the aryls of these oilin-water-type emulsifying agents, advantageously comprising 6 to 20 carbon atoms, more advantageously 6 to 12 carbon atoms.

[0192] Generally, the inverted emulsion comprises between 1 and 4% by weight of oil-in-water emulsifying agent based on the total weight of the inverted emulsion. The oil-in-water emulsifying agent(s) can be added before, during or after polymerization.

[0193] Preferably, the oil-in-water emulsifying agent(s) are added after polymerization.

[0194] The ratio by weight between the hydrophilic phase and the lipophilic phase in the inverted emulsion is advantageously between 50 / 50 and 90 / 10, preferably between 60 / 40 and 85 / 15, more preferably between 70 / 30 and 80 / 20.

[0195] The inverted emulsion advantageously comprises between 20 and 55% by weight of polymeric composition based on the total weight of the inverted emulsion, preferably between 30 and 45% by weight.

[0196] Preparation of the polymeric composition - Water-in- water polymerization

[0197] Water-in- water polymerization consists of polymerizing in an aqueous phase saturated in salts or in charged species, at least one hydrophilic monomer. As the forming polymer chain extends, the polymer precipitates in the form of droplets. Thus, a dispersion of polymer in the form of dispersed droplets is obtained (discontinuous phase) in an aqueous phase saturated in salts (continuous phase). In this system, the two phases are thermodynamically balanced due to the immiscibility of the polymer in the aqueous phase saturated in salts or in charged species.

[0198] Water-in- water polymerization is based on the stabilization of the reactional medium by forcing the forming polymer to precipitate. This polymerization is advantageously achieved according to one of the three following methods:

[0199] - saturation of water by additives making it possible to prevent the polymer particles being formed and being hydrated in contact with the continuous phase. These are mainly salts or ionic species which prevent the solubilization of the compounds by shielding the surface charges and by the ionic force in solution that they generate.

[0200] - saturation of water by additives making it possible to limit the deployment of polymers resulting from the polymerization by a steric bulk mechanism. This is mainly stabilizing polymer;

[0201] - a combination of the two preceding methods.

[0202] These additives (salts or ionic species preventing the solubilization of compounds) make it possible to maintain the compounds present in the discontinuous phase in a good dispersion state, and therefore to avoid decantation, creaming or coacervate forming phenomena. All of these additives act on variables of Stokes law (density, viscosity of the continuous phase).

[0203] The salts are not limited by their nature. These can advantageously be alkaline metal salts, alkaline earth metal salts, organic cation salts (like ammoniums) and mixtures thereof.

[0204] In the case of the invention, the stabilizing polymer corresponds to the host polymer.

[0205] The dispersion advantageously comprises between 5 and 45% by weight of polymeric composition based on the total weight of the dispersion, preferably between 10 and 40% by weight, more preferably between 15 and 35% by weight.

[0206] During water-in-water polymerization, the dispersion can further comprise fluidifying additives, like polyfunctional alcohols, for example glycerol, polyethyleneglycol and polypropyleneglycol; glycol polyalkylenes or water-in-oil emulsifying agents.

[0207] A person skilled in the art will know how to choose and adapt the operating conditions to optimise the water-in- water polymerization according to the polymeric composition that they seek to obtain, as this remains routine adjustments.

[0208] Physical features of the polymeric composition

[0209] The polymeric composition has a Brookfield viscosity, advantageously of between 100 and lOOOOcps, preferably between 200 and 5000cps.

[0210] The present invention also relates to a method for manufacturing a sheet of paper comprising the following steps: a / preparation of a dry market pulp sheet such as described above, b / preparation of a sheet of paper comprising the following steps:

[0211] - disintegration of the dry market pulp sheet in an aqueous medium to form a thick pulp,

[0212] - dilution of the thick pulp to form a diluted pulp,

[0213] - formation of a sheet of paper from the diluted pulp,

[0214] - drying of the sheet of paper.

[0215] The present invention also relates to a dry market pulp, comprising:

[0216] - between 0.001 and 1% by weight of a polymeric composition obtained by polymerization of at least one cationic hydrophilic monomer in the presence of at least one water-soluble polymer selected from the group consisting of poly(dimethylamine-epichlorohydrine), poly(dimethylamine-epichlorohydrine-ethylenediamine) and mixtures thereof;

[0217] - between 79.999 and 99.999% by weight of cellulosic fibers;

[0218] - optionally, between 0.01 and 20% by weight of inorganic particles.

[0219] Examples

[0220] List of abbreviations:

[0221] AM: Acrylamide

[0222] DMAEA.MeCl: Chloromethyl dimethylaminoethyl acrylate

[0223] DMAEMA.BnCl: Chlorobenzyl dimethylaminoethyl methacrylate

[0224] V-50: 2, 2'-Azobis(2 -methylpropionamidine) dichlorhydrate

[0225] DMA: Dimethylamine

[0226] Epi: Epichlorohydrine

[0227] EDA: Ethylenediamine

[0228] PVAm: Polyvinylamine

[0229] Material

[0230] Bentonite: The bentonite used corresponds to the product commercialized under the name of Opazil AOG by Clariant.

[0231] Colloidal silica: The silica used corresponds to the product commercialized under the name KOSTROSOL 0515 by CWK.

[0232] Polyamine (PA): The polyamine (PA) corresponds to the product commercialized under the name FL 2949 SEP by SNF SA and corresponding to a structured poly(DMA-Epi-EDA) (Mw = 225000g / mol).

[0233] Example 1: Preparation of polymeric compositions CPI and CP2 according to the invention

[0234] Example la: Polymeric composition CPI composed of AM / DMAEA.MeCl (70 mol% / 30 mol%) prepared by inverted emulsion polymerization

[0235] In a 1 L reactor equipped with a mechanical stirrer, a thermometer, a coolant and a gaseous nitrogen immersion rod, the lipophilic phase is prepared by introducing 214.2 g of Exxsol D100S oil, 26 g of sorbitan monooleate and 3.8 g of surfactant polymer (Rhodibloc RS). The aqueous phase is prepared by mixing 287.8 g of acrylamide (50% by weight in water), 210.1 g of DMAEA.MeCl (80% by weight in water), 0.7 g of water and 237.5 g of PA. The pH of the solution is adjusted between 4 and 5 with H2SO4 (96% by weight in water). 150 ppm (based on the monomers + polymer weight) of potassium bromate and lOOOppm (based on the monomers + polymer weight) of sodium pentaacetate triamine diethylene are then added as dampers.

[0236] Then, the aqueous phase is transferred into the lipophilic phase and emulsified using an Ultra- Turax at 8000 rpm"1for 1 minute in order to obtain a uniform inverted emulsion.

[0237] The inverted emulsion is deoxygenated with a nitrogen splash for 30 minutes. The polymerization is dampened by adding sodium bisulfite using a syringe pump until reaching the end of exothermicity. The temperature of the reactional medium is then maintained for 1 hour 30 minutes at 55°C. The reactional medium is treated with excess sodium bisulfite in order to reduce the quantity of free monomers in the reactional medium.

[0238] The inverted emulsion obtained corresponds to the polymeric composition CPI.

[0239] The Brookfield viscosity (Module UL, NaCl 1 M, 60 rpm"1, 23°C) of the inverted emulsion obtained is measured. A viscosity UL of 3.61 cps is obtained for a 43% active material.

[0240] Example lb: Polymeric composition CP2 composed of AM / DMAEA.MeCl (70mol% / 30mol%) prepared by water-in-water polymerization

[0241] In a 1 L reactor, equipped with a mechanical stirrer, a thermometer, a coolant and a gaseous nitrogen immersion rod, 195.4 g of AM (50% by weight in water), 135.7 g of DMAEA.MeCl (80% by weight in water), 365 g of saturated water with 240 g of PA, 20 g of glycol polyethylene, 5 g of ammonium sulphate and 5g of citric acid are mixed. The solution is deoxygenated with a nitrogen splash for 30 minutes, then heated at a temperature of between 42 and 45°C. The polymerization is dampened by adding V-50 using a syringe pump until reaching the end of exothermicity. The temperature of the reactional medium is then controlled and maintained at 45 °C for 6 hours.

[0242] The Brookfield viscosity (Module UL, NaCl 1 M, 60 rpm"1, 23°C) of the water in water dispersion obtained is measured. A viscosity UL of 3.41 cps is obtained for a 33.7% active material. Example 1c: Preparation of polymeric compositions CP3 and CP-CE1 to CE8

[0243] Another polymeric composition CP3 is prepared according to Example 1 a, and comparative polymeric compositions CP-CE1 to CP-CE8 are also prepared.

[0244] The details of all polymeric compositions are presented in the table 1 below. Table 1 - Tests carried out. E = invention and CE = comparative exampleacorresponds to the polymer D described in US8916026B2bcorresponds to the polymer 1 described in EP0335576cmixture of AM / DMAEA.MeCl polymer and PA

[0245] Example 2: Evaluation of the performance of the polymeric compositions in a method for preparing dry market pulp

[0246] Eucalyptus raw fiber pulp:

[0247] The wet pulp is obtained by passing through the refiner for 60 minutes, at 2% of dry material concentration in order to obtain a shopper degree of between 22 and 26. After this passing through the refiner, water is added in order to obtain a concentration of 1.5% mass of cellulosic fiber.

[0248] Example 2a: Evaluation of the performances of the polymeric compositions on water retention ( WR V )

[0249] The WRV (Water Retention Value) makes it possible to quantify the amount of water bound to the fiber and that needs a further step of drying to be removed after draining. To measure this value, it is necessary initially to remove the free water using a DDA (Dynamic Drainage Analyser). The polymers are added to the wet pulp (0.8L of pulp at 1.5% mass of cellulosic fiber) in the DDA cylinder under stirring at 1000 rpm:

[0250] T= Os: stirring of the pulp T= 10s: addition of a polymeric composition (0.2 kg / t) described in example 1

[0251] T= 20s: addition of inorganic particles (1.5 kg / t), if necessary

[0252] T= 30s: stopping of the stirring and draining, at a pH of 7, under vacuum at 200 mbar for 60 s.

[0253] The fibrous pad obtained is 10 mm thick and is then pressed under a press delivering 4 bars, in order to remove any trace of free water, then weighed (Wl). The fibrous pad is then dried in a heat chamber at 105°C for 4 hours, then weighed again (W2) to measure the remaining quantity of bound water.

[0254] The %WRV value is calculated with the following formula: 100

[0255] The %WRV values of the different tests are summarized in table 2, the greater the value, the more bound water has been removed. These values are expressed as a percentage % of improvement based on a blank test, i.e. without polymer.

[0256] Table 2 - Effect of the addition of polymeric compositions according to the invention on the retention of bound water on the cellulosic fiber compared with comparative polymeric compositions examples

[0257] These results demonstrate the higher performances of the polymeric composition of the invention to remove the bound water in the paper pulp compared with to the different solutions existing beforehand.

[0258] Especially in the case of comparative polymeric composition CE1 composed of only a poly amine, it can be seen that the quantity of bound water increases compared with a blank test. On the contrary when this polyamine is present during the polymerization of monomers and the resulting complex obtained allows to cancel this effect and a synergetic effect is observed.

[0259] Example 2b: Influence of the thickness of the fiber pad on the retention of bound water (WRV).

[0260] The WRV was measured for various fiber pads having different thickness (according to the invention or not) after addition of the polymeric compositions according to the invention compared with comparative -example polymeric compositions.

[0261] The pH of the drainage has also been evaluated.

[0262] Table 3 - Effect of the addition of a polymeric composition according to the invention or not and the pH on the retention of bound water (WRV) on the cellulosic fiber on fibers pads having different thickness (0.1-50 mm).

[0263] ^thickness of the pad outside the invention

[0264] ** water retention realized at a pH of 4

[0265] These results demonstrate that the composition according to the invention improves the draining of bound water (greater WRV) when the fiber pad has a thickness of at least 1 mm. However, the comparative examples (fiber pads having a thickness of less than 1 mm and / or different polymeric compositions) do not show any noticeable improvement.

[0266] It can be seen that, against all expectations, the composition according to the invention does not provide any improvement in acidic condition when the fiber pad has a thickness of less than 1 mm, especially fiber pads having the thickness of paper sheets.

[0267] These results also show that additives used in order to improve the drainage in a papermaking process do not improve the drainage in the manufacturing of a dry market pulp sheet when the thickness is less than 1 mm and depending on the pH used for draining.

[0268] Example 2c: Evaluation of the polymeric compositions on the turbidity of white water

[0269] Turbidity means the content of material in suspension which affects the fluid (white water). These suspended materials partially correspond to the stickies. Turbidity is measured using a HANNA spectrophotometer, which measures the decrease of the intensity of light radiation under an angle of 90°, at a wavelength of 860 nm and expressed as a %NTU.

[0270] The %NTU values of the different tests are summarized in table 4, the greater the value, the lower the quantity of suspended material is affecting the medium. These values are expressed as a % of improvement based on a blank test, i.e. without polymer. according to the invention and comparative examples

[0271] These results demonstrate the higher performances of the polymeric composition of the invention, in order to reduce the quantity of stickies present in the paper pulp compared with the different solutions existing beforehand.

Claims

Claims1. Method for manufacturing a dry market pulp sheet comprising the following steps:- preparation of a cellulosic fibers aqueous suspension SAI by pulping raw cellulosic material in the presence of water,- addition, to the aqueous suspension SAI of cellulosic fibers, of a polymeric composition obtained by polymerization of at least one cationic hydrophilic monomer in the presence of at least one water-soluble polymer selected from the group consisting of poly(dimethylamine- epichlorohydrine), poly(dimethylamine-epichlorohydrine-ethylenediamine) and mixtures thereof, in order to form an aqueous suspension SA2,- formation of a fibrous pad having a thickness comprised between 1 mm and 100 mm, by drainage of the aqueous suspension SA2 on a wire at a pH comprised between 6 and 8,- formation of a paper pulp sheet by pressing this fibrous pad,- drying of the paper pulp sheet, in order to obtain a dry market pulp.

2. Method according to claim 1 , characterized in that the method comprises the addition, to the aqueous suspension SAI or SA2, of inorganic particles before the formation of the fibrous pad.

3. Method according to claim 2, characterized in that the inorganic particles are bentonite particles.

4. Method according to one of claims 2 or 3, characterized in that the addition of inorganic particles and of the polymeric composition is done in sequence, the inorganic particles being added before the polymeric composition.

5. Method according to one of claims 1 to 4, characterized in that the dry market pulp sheet has a cellulosic fiber weight of between 250 and 5000 g / m2.

6. Method according to one of claims 1 to 5, characterized in that the polymeric composition is obtained from the polymerization of at the least one cationic hydrophilic monomer in the presence of at least one monomer selected from non-ionic hydrophilic monomer, anionic hydrophilic monomer, zwitterionic hydrophilic monomer, and mixtures thereof, preferably at least one non-ionic hydrophilic monomer in the presence of the at least one water-soluble polymer7. Method according to one of claims 1 to 6, characterized in that 100 wt% of the carbon atoms in the polymeric composition originates from a feedstock comprising recycled material or materials of biological origin, wherein said carbon atoms are preferably have a biobased carbon content of 100% as measured in accordance with ASTM D6866-21, Method B.

8. Method according to one of claims 1 to 7, characterized in that the polymeric composition is obtained by inverted emulsion polymerization or by water-in- water polymerization.

9. Method according to one of claims 1 to 8, characterized in that the polymeric composition is obtained by inverted emulsion polymerization.

10. Dry market pulp comprising:- between 0.001 and 1% by weight of a polymeric composition obtained by polymerization of at least one cationic hydrophilic monomer in the presence of at least one water-soluble polymer selected from the group consisting of poly(dimethylamine-epichlorohydrine), poly(dimethylamine-epichlorohydrine-ethylenediamine) and mixtures thereof;- between 79.999 and 99.999% by weight of cellulosic fibers;- optionally, between 0.01 and 20% by weight of inorganic particles.

11. Method according to one of claims 1 to 9, characterized in that the monomer(s) used in the invention are prepared by enzymatic catalysis or extracted from renewable raw material.

12. Method according to one of claims 1 to 9 or 11, characterized in that the energy used to carry out the method is derived from a heat pump or of renewable origin, for example wind power, photovoltaics, or from fuel cell or lithium battery type.