Tanning agent

Abstract

The present invention relates to a tanning agent consisting of a polymer of at least: - 0.01 to 12 mol% of N-methylol(meth)acrylamide; and - 50 to 99.99 mol% of at least one anionic hydrophilic monomer.

Description

[0019] The term "tanning agent" refers to a polymer of at least two different monomers (N-methylol(meth)acrylamide + anionic hydrophilic monomer). Preferably, the tanning agent according to the invention is water-soluble.

[0020] By "hydrophilic monomer" is meant a monomer which has an octanol / water partition coefficient, Kow, less than or equal to 1.

[0021] By "hydrophobic monomer" is meant a monomer which has an octanol / water partition coefficient, Kow, greater than 1.

[0022] The octanol / water partition coefficient, Kow, represents the ratio of the concentrations (g / L) of a monomer between the octanol phase and the aqueous phase. It is determined at 25 °C in an octanol / water mixture having a volume ratio of 1:1, at a pH between 6 and 8. It is defined as follows:

[0023] [Math.l] K _ [monomer]oct,7,IQ; OM' [monomer] water

[0024] 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.

[0025] According to the invention, "X and / or Y" means "X", or "Y", or "X and Y".

[0026] Also part of the invention are all possible combinations between the different embodiments disclosed, whether they are embodiments preferred or given as examples. Furthermore, when ranges of values ​​are indicated, the bounds are part of those ranges. Disclosure also includes all combinations of the bounds within those ranges. For example, the ranges of values ​​"1-20, preferably 5-15" imply disclosure of the ranges "1-5", "1-15", "5-20", and "15-20", and the values ​​1, 5, 15, and 20.

[0027] All the particular and / or preferred modes described in the invention can be combined provided that they are not incompatible. Tanning agent

[0028] The tanning agent consists of a polymer of at least: - 0.01 to 12 mol% of N-methylol(meth)acrylamide; and - 50 to 99.99 mol% of at least one anionic hydrophilic monomer.

[0029] Molar percentages are expressed in relation to the total quantity of monomers, excluding any branching or structural agents.

[0030] In a preferred mode, N-methylol(meth)acrylamide is N-methylolmethacryl amide.

[0031] The tanning agent containing N-methylolmethacrylamide offers performance equivalent to the tanning agent containing N-methylolacrylamide while exhibiting lower toxicity and environmental impact.

[0032] The amount of N-methylol(meth)acrylamide is between 0.01 and 12 mol%, preferably between 0.1 and 6 mol%, more preferably between 0.2 and 3 mol%.

[0033] Advantageously, the other hydrophilic anionic monomer(s) that may be used in the context of the invention may be chosen from a wide range. These monomers may have a vinyl functional group, in particular acrylic, maleic, fumaric, malonic, or allylic. They may also contain a carboxylate, phosphonate, phosphate, sulfonate, sulfate, or other anionically charged group. Advantageously, the anionic hydrophilic monomer is one or more monomers selected from the group consisting of: acrylic acid, methacrylic acid, dimethylacrylic acid, crotonic acid, maleic acid, fumaric acid, 3-acrylamido-3-methylbutanoic acid, strong acid-type monomers having, for example, a sulfonic acid or phosphonic acid function, such as vinylsulfonic acid, vinylphosphonic acid, allylsulfonic acid, methallylsulfonic acid, 2-methylidenepropane-3-disulfonic acid,2-Sulfoethyl methacrylate, sulfopropyl methacrylate, sulfopropyl acrylate, 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 these monomers, advantageously, such as their salts of alkali metals, alkaline earth metals, or ammonium. Preferably, the anionic hydrophilic monomer is chosen from acrylic acid and methacrylic acid.

[0034] The polymer (tanning agent) comprises between 50 and 99.99 mol% of anionic hydrophilic monomer(s), preferably between 75 and 99.9 mol%, more preferably between 97 and 99.8 mol%.

[0035] In one embodiment of the invention, the hydrophilic anionic monomer(s) may be partially or totally salified.

[0036] By salification, we mean the substitution of a proton of at least one acidic functional group of the type -Ra(=O)-OH (with Ra representing P, S, or C) of the anionic hydrophilic monomer by a metal cation or an organic cation to form a salt of the type -Ra(=O)-O X+ (X+ being a metal cation or an organic cation). In other words, the unsalified form corresponds to the acidic form of the monomer, for example Rb-C(=O)-OH in the case of the carboxylic acid functional group, while the salified form of the monomer corresponds to the form Rb-C(=O)-O X+, X+ being a metal cation or an organic cation. The salification of the acidic functional groups may be partial or complete.

[0037] The metal cation is advantageously an alkali metal salt (Li, Na, K...) or an alkaline earth metal salt (Ca, Mg...), and the organic cation is advantageously the ammonium ion or a tertiary ammonium compound. Sodium salts are preferred.

[0038] Salification can take place, partially or totally, before, during or after polymerization.

[0039] Advantageously, 30 to 100 mol% of the total anionic hydrophilic monomers included in the tanning agent are in salified form, preferably 50 to 100 mol%.

[0040] In addition to N-methylol(meth)acrylamide and the anionic hydrophilic monomer, the tanning agent may further comprise at least one other monomer, selected from: non-ionic hydrophilic monomers other than N-methylol(meth)acrylamide, cationic hydrophilic monomers, zwitterionic hydrophilic monomers, hydrophobic monomers and mixtures thereof.

[0041] Advantageously, the hydrophilic non-ionic monomer(s) other than N-methylol(meth)acrylamide that may be used in the context of 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-dialkylmethacrylamide, alkoxylated esters of acrylic acid, alkoxylated esters of methacrylic acid, N-vinylpyrrolidone, N-methylol(meth)acrylamide, N-vinyl caprolactam, acryloyl chloride, N-vinylformamide (NVF), N-vinyl acetamide, N-vinyl imidazole, N-vinyl succinimide, acryloyl morpholine (ACMO), glycidyl methacrylate, vinyl acetate, glyceryl methacrylate, diacetone acrylamide, methacrylic anhydride, acrylonitrile, maleic anhydride, itaconic anhydride, hydroxyalkyl (meth)acrylates, thioalkyl (meth)acrylates, isoprenol and its alkoxylated derivatives, hydroxyethyl (meth)acrylates and their alkoxylated derivatives, hydroxypropyl (meth)acrylate and its alkoxylated derivatives, and mixtures thereof. Among these nonionic monomers, the alkyl groups are advantageously located at C1-C5, and more advantageously at C1-C3.

[0042] The tanning agent advantageously comprises between 0.1 and 49.99 mol% of non-ionic hydrophilic monomer(s) other than N-methylol(meth)acrylamide.

[0043] The hydrophilescationic monomer(s) that can be used in the context of the invention are chosen, in particular, from vinyl-type monomers, especially acrylamide, acrylic, allylic, or maleic monomers having a protonable amine or ammonium function, advantageously a quaternary ammonium. Advantageously, the hydrophilescationic monomer(s) used in the context of the invention are chosen from the group consisting of: diallyldialkyl ammonium salts such as dimethyldiallylammonium chloride (DADMAC); acidified or quaternized dialkyl-aminoalkyl(meth)acrylamides, such as (3-methacrylamidopropyl)trimethylammonium chloride (MAPTAC), (3-acrylamidopropyl)trimethylammonium chloride (APTAC); acidified or quatemized salts of dialkyl aminoalkyl acrylate such as quatemized or salified dimethylaminoethyl acrylate (ADAME);acidified or quaternized salts of dialkyl aminoalkyl methacrylate such as quaternized or salified dimethylaminoethyl methacrylate (MADAME); acidified or quaternized salts of N,N-dimethylallylamine; acidified or quaternized salts of diallylmethylamine; acidified or quaternized salts of diallylamine; vinylamine obtained by the (basic or acidic) hydrolysis of an amide group -N(R2)-CO-R1 with R1 and R2 being, independently, a hydrogen atom or an alkyl chain of 1 to 6 carbons, for example polyvinylamine from the hydrolysis of a (co)polymer of vinylformamide; vinylamine from the Hofmann degradation on a (co)polymer of (meth)acrylamide or acrylonitrile; and mixtures thereof. Advantageously, the alkyl groups are in the Ci-C5 position, preferably in CrC3, and can be linear or branched chains.

[0044] The tanning agent advantageously comprises less than 50 mol% of cationic hydrophilic monomer(s), preferably less than 40 mol%, more preferably less than 30 mol%, more preferably less than 20 mol%, more preferably less than 10 mol% and more preferably less than 5 mol%.

[0045] A person skilled in the art will know how to prepare the quaternized monomers, for example by means of a quaternizing agent of type R-X1, R being an alkyl group and X1 being a halogen or a sulfate.

[0046] By “quaternizing agent” is meant a molecule capable of alkylating a tertiary amine.

[0047] The quaternizing agent may be selected, in particular, from dialkyl sulfates comprising from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms, or alkyl halides comprising from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms. Preferably, the quaternizing agent is selected from methyl chloride, benzyl chloride, dimethyl sulfate, or diethyl sulfate.

[0048] In addition, the present invention also covers DADMAC, APTAC and MAPTAC type monomers in which the counter-ion is a sulfate, a fluoride, a bromide or an iodide instead of chloride.

[0049] In a preferred mode, the tanning agent is devoid of cationic hydrophilic monomers.

[0050] When the tanning agent comprises hydrophobic monomers, they are present in such quantity that the polymer remains soluble in water.

[0051] In a preferred mode, the tanning agent is devoid of hydrophobic monomers.

[0052] The quantities of the different monomers will be adjusted by a person skilled in the art so as not to exceed 100% molar during the preparation of the tanning agent.

[0053] In one embodiment, the tanning agent may be partially or totally post-hydrolyzed.

[0054] Post-hydrolysis is a hydrolysis reaction of the polymer after its formation by polymerization of the monomers. This step consists of the reaction of hydrolyzable functional groups of advantageously non-ionic monomers, more advantageously amide or ester groups, with a hydrolyzing agent. This hydrolyzing agent can, for example, be an enzyme, an ion-exchange resin, or a Brpnsted acid metal (e.g., a hydrohalic acid) or a Brpnsted base (e.g., an alkali hydroxide or an alkaline earth hydroxide). Preferably, the hydrolyzing agent is a Brpnsted base. During this post-hydrolysis step of the polymer containing amide or ester groups, the number of carboxylic acid groups increases. Indeed, the reaction between the base and the amide or ester groups present in the polymer produces carboxylate groups. Structure of the tanning agent

[0055] According to the invention, the tanning agent consists of a polymer which can have a linear, branched, ramified, star-shaped or comb-shaped structure, advantageously linear. This structure can be obtained, according to the general knowledge of a person skilled in the art, for example by selection of the initiator, the transfer agent, the polymerization technique such as reversible addition-fragmentation chain transfer polymerization (RAFT), nitroxide-mediated polymerization (NMP) or atom transfer radical polymerization (ATRP), the incorporation of structural monomers, or the concentration.

[0056] The tanning agent can be a static polymer, a block polymer or a gradient polymer.

[0057] By "statistical polymer" is meant a polymer in which the arrangement of the monomers is random. A statistical polymer is obtained by placing all the monomers composing the polymer at the beginning of polymerization.

[0058] By “block polymer” we mean di-block, tri-block or multi-block, grafted sequenced polymers, branched sequenced polymers (also known as linear star polymers).

[0059] Polymers having a block structure are polymers composed of at least two blocks of different monomers. Diblock polymers have two distinct blocks; triblock polymers have three, and so on. They are advantageously obtained by successively polymerizing different species of monomers.

[0060] In one embodiment, the tanning agent has an XY-type structure when composed of two different monomers. In other words, the first fraction comprises only X monomers. These are polymerized initially, and when all the X monomers have reacted, the second fraction, comprising the Y monomers, is added.

[0061] In one embodiment, the tanning agent has an XYZ-type structure when composed of three different monomers. In other words, the first fraction comprises only X monomers. These are polymerized initially, and when all the X monomers have reacted, the second fraction, comprising the Y monomers, is added. When all the Y monomers have reacted, the third fraction, comprising the Z monomers, is added.

[0062] This polymerization system can be extended to obtain so-called multiblock polymers having a structure Xi-Yi-...-Xn_i-Yn_i-Xn-Yn, n being an integer greater than or equal to 2 representing the number of blocks.

[0063] By “gradient polymer” is meant a polymer whose monomeric composition varies in a controlled manner throughout the polymer chain.

[0064] Polymers with a gradient structure are polymers composed of at least two monomers in which the change in monomer composition is gradual, unlike block polymers, which have an abrupt change in composition, and random polymers, which do not have a continuous change in composition. In the gradient polymer, due to the gradual change in composition along the length of the polymer chain, less intra-chain and inter-chain repulsion is observed.

[0065] The gradient can be formed by a spontaneous or forced gradient. Spontaneous gradient polymerization is due to a difference in the reactivity of the monomers. Forced gradient polymerization involves varying the composition of monomers introduced throughout the polymerization time.

[0066] A process for preparing a forced-gradient polymer comprises (1) introducing a first fraction of monomers into a reactor, (2) adding at least one additional fraction of monomers advantageously different from the first, and (3) polymerizing the monomers introduced into the reactor. Polymerization of the monomers is initiated as soon as the first fraction is introduced.

[0067] The addition of the additional monomer fraction can be carried out in parallel with the introduction of the first monomer fraction into the reactor (the introduction of the fractions can therefore start and finish simultaneously). Alternatively, the start of the first monomer feed (first fraction) into the reactor can precede the start of the addition of a second monomer fraction. Alternatively, a first and second fraction can be introduced simultaneously, but the addition time of the second fraction may be longer than the introduction time of the first fraction into the reactor. This embodiment is also applicable to processes using at least three monomer fractions.

[0068] The branching agent is advantageously chosen from: - structural agents, which can be chosen from the group comprising polyethylenic unsaturation compounds (having at least two unsaturated functions, with the exception of diallyldialkyl ammonium type compounds), such as vinyl functions, particularly allylic or acrylic, and examples include methylene bisacrylamide (MBA), triallyamine, or tetraallylammonium chloride or 1,2-dihydroxyethylene bis-(N-acrylamide), - compounds having at least two epoxy functional groups, - Compounds having at least one unsaturated function and one epoxy function, - Macro-initiators such as polyperoxides, polyazo compounds and polytransfer agents such as polymer-capturing polymers and polyols, - Functionalized polysaccharides, - water-soluble metal complexes composed of: * of a metal with a valence greater than 3 such as, by way of example and without limitation, aluminium, boron, zirconium or titanium, and * of a ligand bearing a hydroxyl function.

[0069] When the tanning agent includes a branching agent, it remains soluble in water. A person skilled in the art will know how to adjust the amount of branching agent, and possibly the amount of transfer agent, to achieve this result.

[0070] In one embodiment, the tanning agent is devoid of a branching agent.

[0071] In a preferred mode, the tanning agent includes a transfer agent.

[0072] The transfer agent is advantageously chosen from the group consisting of: the 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, allyl phosphites, allyl mercaptans, such as n-dodecyl mercaptan, sodium methallysulfonate, calcium methallysulfonate, magnesium methallysulfonate, potassium methallysulfonate, ammonium methallysulfonate, alkyl phosphites such as trialkyl (C12-C15) phosphites, di-oleyl hydrogen phosphites, dibutyl phosphite, dialkyldithiophosphates such as 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 formate.

[0073] The quantity of transfer agent in the tanning agent is advantageously between 500 and 500,000 ppm, by weight, relative to the total weight of the monomers of the tanning agent, preferably between 1,000 and 400,000 ppm by weight, more preferably between 10,000 and 300,000 ppm by weight, even more preferably between 50,000 and 250,000 ppm by weight.

[0074] The tanning agent advantageously has a weight average molecular weight between 500 and 100,000 g / mol, preferably between 1,000 and 30,000 g / mol, more preferably between 2,000 and 15,000 g / mol.

[0075] The molecular weight can be determined by size-exclusion chromatography using a measuring standard. For example, the following instrument can be used: - Agilent® 1260 Infinity System: * Chromatographic columns: * PL Aquagel guard column * PL Aquagel OH 20 * PL Aquagel OH 40 * Solvent: * 100 mM NaCl in water * NaH2PO4 10 mM in water * NaN3 0.02% by weight in water * Flow rate: 0.8 mL / min * Column temperature: 35°C * Refractometer temperature: 35°C * Injection volume: 100 pL * Analysis time: 45 minutes

[0076] Calibration is performed using average molecular weight standards by weight of polyacrylic acids (source “American polymer standards”) having the following characteristics: - Standard 1: Molecular weight = 900 g / mol - Standard 2: Molecular weight = 1250 g / mol - Standard 3: Molecular weight = 2925 g / mol - Standard 4: Molecular weight = 5800 g / mol - Standard 5: Molecular weight = 7,500 g / mol - Standard 6: Molecular weight = 28,000 g / mol - Standard 7: Molecular weight = 47,500 g / mol - Standard 8: Molecular weight = 193,800 g / mol

[0077] In one embodiment, the tanning agent consists of a polymer made up of: - 0.01 to 12 mol% of N-methylol(meth)acrylamide, preferably 0.1 to 6 mol%, more preferably 0.2 to 3 mol%; and - 88 to 99.99 mol% of (meth)acrylic acid, preferably 94 to 99.9 mol%, more preferably 97 to 99.8 mol%.

[0078] In one embodiment, the tanning agent consists of a polymer made up of: - 0.01 to 12 mol% of N-methylol(meth)acrylamide, preferably 0.1 to 6 mol%, more preferably 0.2 to 3 mol%; - between 0.1 and 99.89 mol% of methacrylic acid, preferably 0.1 to 99.8 mol%, more preferably 97 to 99.7 mol%; - between 0.1 and 99.89 mol% of acrylic acid, preferably 0.1 to 99.8 mol%, more preferably 0.1 to 99.7 mol%, the sum of the quantities of methacrylic acid and acrylic acid being at least equal to 50 mol%.

[0079] In one embodiment, the tanning agent consists of a polymer made up of: - 0.01 to 12 mol% of N-methylol(meth)acrylamide, preferably 0.1 to 6 mol%, more preferably 0.2 to 3 mol%; - 0.1 to 99.89 mol% of methacrylic acid, preferably 0.1 to 99.8 mol%, more preferably 0.1 to 99.7 mol%; - 0.1 to 99.89 mol% of acrylic acid, preferably 0.1 to 99.8 mol%, more preferably 0.1 to 99.7 mol%; the sum of the quantities of methacrylic acid and acrylic acid being at least equal to 50 mol%. Process for preparing a tanning agent

[0080] The invention also relates to a method for preparing a tanning agent made of a polymer of at least: - 0.01 to 12 mol% of N-methylol(meth)acrylamide monomer; and - 50 to 99.99 mol% of at least one anionic hydrophilic monomer, this process comprising at least the following successive steps: i) mixing of the monomers with at least one polymerization initiator in a polar solvent; ii) radical polymerization of monomers to obtain the tanning agent.

[0081] By radical polymerization, we include free radical polymerization using UV, azo, redox or thermal initiators as well as controlled radical polymerization (CRP) techniques or matrix polymerization techniques.

[0082] Examples of controlled radical polymerization techniques include, but are not limited to, iodine transfer polymerization (ITP), nitroxide-mediated polymerization (NMP), atom transfer radical polymerization (ATRP), and reversible addition-fragmentation chain transfer polymerization (RAFT), of which includes MADIX technology (“MAcromolecular Design by Interchange of Xanthates”), various variations of polymerizations with organometallic compounds (“Organometallic Mediated Radical Polymerization” (OMRP)), and radical polymerization controlled by heteroatomic compounds (“OrganoHeteroatom-mediated Radical Polymerization” (OHRP)).

[0083] In a preferred mode, the polymerization is carried out by reversible addition-fragmentation chain transfer polymerization (RAFT).

[0084] RAFT is a reversible deactivation radical polymerization (RDRP) technique that combines both the ease of implementation of conventional radical polymerization and the liveness of ionic polymerization.

[0085] It is based on a reversible activation-deactivation equilibrium between a dormant species and an active species (growing macroradical). This activation-deactivation process allows the chains to grow at the same rate until the monomer is completely consumed, making it possible to control the molecular weights of the polymers and obtain narrow molecular weight distributions. This also minimizes compositional heterogeneity. The reversible deactivation of the growing chains minimizes irreversible termination reactions. The vast majority of the polymer chains remain in a dormant state and are therefore reactivatable. It is then possible to functionalize the chain ends to initiate other polymerization modes or to create chain extensions. This is the key to achieving high molecular weights, controlled compositions, and architectures.

[0086] Controlled radical polymerization therefore has the following distinctive aspects: 1. the number of polymer chains is fixed throughout the duration of the reaction, 2. the polymer chains all grow at the same rate, which results in: * a linear increase in molecular weights, * a tight distribution of molecular weights, 3. the average molecular weight is controlled by the monomer / precursor molar ratio.

[0087] The controlled nature of the chain is all the more pronounced when the rate of reactivation of the chains into radicals is much greater than the rate of chain growth (propagation). However, in some cases, the rate of reactivation of the chains into radicals is greater than or equal to the rate of propagation. In these cases, conditions 1 and 2 are not observed and, consequently, control of the molecular weights is not possible.

[0088] Reversible addition-fragmentation chain transfer polymerization requires the use of a control agent.

[0089] In the context of the invention, the control agent is water-soluble and of formula (I):

[0090] [Chem.l] (I)

[0091] in which - Z represents an oxygen atom (O), a sulfur atom (S) or an amine (NR3); - Ri, R2, and R3, whether identical or different, represent: * a group (i), alkyl, acyl, alkenyl or alkynyl, possibly substituted, or * a carbon ring (ii), saturated or unsaturated, possibly substituted or aromatic, or * a heterocycle (iii), saturated or unsaturated, possibly substituted or aromatic, these groups and rings (i), (ii) and (iii) being able to be substituted by substituted aromatic groups or by alkoxycarbonyl or aryloxycarbonyl groups (-COOR), carboxy (-COOH), acyloxy (-O2CR), carbamoyl (-CON(R)2), cyano (-CN), alkylcarbonyl, alkylarylcarbonyl, arylcarbonyl, arylalkylcarbonyl, phthalimido, maleimido, succinimido, amidino, guanidimo, hydroxy (-OH), amino (-N(R)2), halogen, allyl, epoxy, alkoxy (-OR), S-alkyl, S-aryl, groups exhibiting a hydrophilic or ionic such as alkali salts of carboxylic acids, alkali salts of sulfonic acid, alkylene polyoxide chains (POE, POP), cationic substituents (quaternary ammonium salts); - R represents an alkyl or aryl group in Ci-C20; - R3 can also represent a hydrogen atom; - Q is a linear or structured chain comprising n identical or different hydrophilic monomers comprising at least one ethylenic function; - n is an integer between 0 and 500, advantageously between 1 and 500, more advantageously between 1 and 100. When n is equal to 0, Q is a single bond between the sulfur atom and the R2 group.

[0092] The monomer or monomers used to form Q are advantageously chosen from the same hydrophilic monomers as those described to form the tanning agent.

[0093] In the functions N(R)2, the two groups R can be identical or different from each other.

[0094] According to a preferred mode, the water-soluble control agent of formula (I) is a dithiocarbonate or xanthate derivative in which Z represents an oxygen atom (O).

[0095] According to another preferred embodiment, the water-soluble controlling agent has formula (I) in which: - Z represents an oxygen atom (O); - Q is a linear or structured chain obtained from 0 to 100 monomers comprising at least one non-ionic hydrophilic monomer and / or at least one anionic hydrophilic monomer and / or at least one cationic hydrophilic monomer.

[0096] According to another preferred embodiment, the water-soluble controlling agent has formula (I) in which: - Z represents an oxygen atom (O); - Q is a linear or structured chain obtained from 0 to 100 monomers comprising at least one non-ionic hydrophilic monomer and / or at least one anionic hydrophilic monomer and / or at least one monomer containing an LCST group.

[0097] According to another preferred embodiment, the water-soluble control agent has formula (II):

[0098] [Chem.2]

[0099] in which n is an integer between 0 and 100, preferably between 1 and 50.

[0100] In another preferred mode, the control agent is of formula (IV) in which Z represents a sulfur atom (S).

[0101] In another preferred mode, the control agent is of formula (III):

[0102] [Chem.3] (IID

[0103] wherein: the R3s are identical or different, independently represent an H or a CH3 or a salt, advantageously chosen from the salts of alkali metals (Li, Na, K...), alkaline earth metals (Ca, Mg...) or ammonium ions (for example the ammonium ion or a tertiary ammonium), preferably a sodium salt.

[0104] In another preferred mode, the controlling agent is a trithiocarbonate of the following formula (IV):

[0105] [Chem.4] COOR3 (IV)

[0106] in which Z=S, Q is a chain of an acrylamide monomer and: - the R3s are identical or different, independently represent an H or a CH3 or a monovalent or divalent cation, advantageously chosen from the cations of alkali metals (Li, Na, K...), alkaline earth metals (Ca, Mg...) or ammonium ion (for example the ammonium ion or a tertiary ammonium), preferably it is sodium; - n and n' are independent integers between 1 and 100, preferably between 1 and 50.

[0107] In another preferred mode, the control agent has the following formula (V):

[0108] [Chem.5] (V)

[0109] wherein the R3s are identical or different, independently represent an H, a CH3 or a salt, advantageously chosen from the salts of alkali metals (Li, Na, K...), alkaline earth metals (Ca, Mg...) or ammonium ions (for example the ammonium ion or a tertiary ammonium). Preferably it is a sodium salt.

[0110] In another preferred mode, the control agent is of formula (VI): [YES] [Chem.6] (VI)

[0112] in which Z=S, Q is a chain of an acrylamide monomer and: - the R3s are identical or different, independently representing an H, a CH3 or a monovalent or divalent cation, advantageously chosen from alkali metal cations (Li, Na, K...), alkaline earth metal cations (Ca, Mg...) or ammonium ion (for example the ammonium ion or a tertiary ammonium), preferably sodium; and - n is an integer, between 1 and 100, preferably between 1 and 50.

[0113] The polymerization initiators used are advantageously chosen from among compounds that dissociate into radicals under the polymerization conditions, for example: organic peroxides, hydroperoxides, hydrogen peroxide, persulfates, azo compounds, and redox salts. The use of water-soluble initiators is preferred. In some cases, it is advantageous to use mixtures of various polymerization initiators, for example, mixtures of redox salts and azo compounds.

[0114] In a preferred mode, the polymerization initiator is a pair of redox salts.

[0115] The reducing agent of the redox salt pair is advantageously chosen from among the sulfites of alkali metal salts (Li, Na, K...), alkaline earth metals (Ca, Mg...) or ammonium (for example the ammonium ion or a tertiary ammonium, sulfur dioxide, metabisulfites of alkali metal salts (Li, Na, K...), alkaline earth metals (Ca, Mg...) or ammonium (for example the ammonium ion or a tertiary ammonium).

[0116] The oxidant of the redox salt couple is advantageously chosen from among peroxides such as tert-butyl hydroperoxide, perfulfates of alkali metals (Li, Na, K...), of alkaline earth metals (Ca, Mg...) or of ammonium (for example the ammonium ion or a tertiary ammonium, hydrogen peroxide).

[0117] In one embodiment, the polymerization is initiated by the Fenton reaction. The Fenton reaction is an oxidation reaction that involves initiating the decomposition reactions of hydrogen peroxide (H2O2) by metallic salts. in order to generate radical species, preferentially hydroxyl radicals HO*.

[0118] Advantageously, the quantity of initiator is between 500 and 500,000 ppm relative to the weight of the monomers of the tanning agent, preferably between 1,000 and 400,000 ppm, more preferably between 10,000 and 300,000 ppm, and even more preferably between 50,000 and 200,000 ppm.

[0119] The initiator(s) can be added all at once, in several stages, or continuously, i.e., by pouring. Preferably, the initiator(s) are added continuously.

[0120] In the case of redox salts, the reducing agent and the oxidizing agent can be added continuously during polymerization, i.e., by pouring, in parallel, or one after the other. Advantageously, at least one reducing agent or oxidizing agent is added with the monomers, and the other component of the redox couple is added continuously, i.e., by pouring throughout the polymerization process.

[0121] The monomers are polymerized in a polar solvent, advantageously chosen from: water, isopropanol, terbutanol, ethanol, acetone, dimethyl sulfoxide, tetrahydrofuran, dimethylformamide and mixtures thereof. Preferably, it is water.

[0122] Generally, polymerization can take place in solution; in gel; by precipitation; in emulsion (aqueous or inverse); in suspension; or in water in water, preferably it takes place in solution.

[0123] The quantity of active material during polymerization is advantageously between 15 and 60% by weight relative to the total weight of the reaction medium, preferably between 25 and 55% by weight, more preferably between 35 and 50% by weight.

[0124] The term "active material" refers to all polymerized compounds. This includes monomers, initiators, and optionally branching and transfer agents. Active material does not include solvent(s). It does not include surfactants and oil used in emulsion polymerization or any salts (precipitation polymerization, etc.).

[0125] The term "reaction medium" refers to all the compounds used during polymerization, i.e., the active ingredient and the solvent(s). The reaction medium includes surfactants and oil used in emulsion polymerization or any salts (precipitation polymerization, etc.).

[0126] In a preferred mode, the radical polymerization of the monomers is carried out in the presence of at least one transfer agent, 15 to 35% by weight of at least one transfer agent, relative to the total weight of transfer agent, being added during step i), and 65 to 85% by weight of at least one transfer agent, relative to the total weight of transfer agent, being poured throughout step ii).

[0127] The polymerization process according to the invention can be carried out in batch, semi-batch or continuous mode; advantageously, it is carried out in batch mode. Preferably, it is carried out by solution polymerization in batch mode.

[0128] During polymerization, it is possible to pour the various components constituting the polymer that forms the tanning agent. For example, it is possible to pour N-methylol(meth)acrylamide, and / or the anionic monomer(s), or any other monomers that may constitute the tanning agent. It is also possible to pour the branching agent and / or the transfer agent when at least one of the two is present, or to pour the initiator.

[0129] In a preferred mode, N-methylol(meth)acrylamide is cast during the polymerization step.

[0130] In a preferred mode, N-methylol(meth)acrylamide and at least one anionic hydrophilic monomer are cast during polymerization.

[0131] In a preferred mode, all the monomers constituting the tanning agent are cast during polymerization. The temperature at which polymerization is initiated is advantageously between 0 °C and 50 °C.

[0132] In a preferred mode, all the constituents of the tanning agent are cast during polymerization in the polar solvent.

[0133] Once polymerization has begun, the temperature is controlled to be advantageously between 1°C and less than 150°C, preferably between 20 and 100°C, more preferably between 20 and 90°C.

[0134] The pressure during polymerization can be controlled. It is advantageously between 800 mbar and 10 bar, preferably between 900 mbar and 5 bar. More preferably, polymerization is carried out at atmospheric pressure.

[0135] Pressure control will be implemented by a person skilled in the art, as this remains within the scope of their general knowledge.

[0136] The polymerization time is advantageously between 30 seconds and 480 minutes, preferably between 30 minutes and 300 minutes, more preferably between 75 minutes and 200 minutes.

[0137] In one embodiment, the process of the invention comprises, following polymerization, a step iii) of removing residual monomers. The removal of residual monomers can be carried out, for example, by the addition of a radical precursor.

[0138] In one embodiment, the polymerization of the monomers constituting the tanning agent is carried out in the presence of cyclodextrin, preferably α-cyclodextrin.

[0139] The molar ratio between α-cyclodextrin and N-methylolacrylamide is advantageously between 10:1 and 1:10, preferably 5:1 and 1:5, more preferably 2:1 and 1:2.

[0140] The invention also relates to a leather tanning process comprising bringing a hide into contact with at least one tanning agent according to the invention.

[0141] The invention also relates to leather obtained according to the tanning process of the invention.

[0142] Finally, the invention relates to a method of manufacturing articles for leather goods, gloves, shoemaking, furniture or saddlery with leather obtained according to the tanning process of the invention.

[0143] The following examples illustrate the invention without however limiting it. Example * Summary

[0144] Polymer Ply

[0145] In a 2 L reactor fitted with a condenser, comprising a Cl composition of 220.4 g of water, 4 solutions are poured simultaneously: - 208.6 g of an SI solution of methacrylic acid in 120 minutes; - 32.6 g of an S2 solution of N-methylolacrylamide (48% by weight in water) in 120 minutes; - 89.7 g of an S3 solution of sodium persulfate (15% by weight in water) in 130 minutes; - 224.1 g of an S4 solution of sodium hypophosphite (25% by weight in water) in 130 minutes; The temperature is controlled between 82 and 87 °C, allowing the polymerization of monomers in solution.

[0146] Once the pours are finished, 294.5 g of water, then 194 g of sodium hydroxide (at 50% by weight in water), are added in order to convert methacrylic acid into methacrylate, while controlling the temperature of the medium so that it does not exceed 75°C.

[0147] A solution comprising the Pli polymer is then obtained.

[0148] The PI 1 polymer synthesis protocol is repeated, adjusting the compositions monomerics and the amount of sodium hypophosphite to obtain the PI-P 16 polymers whose compositions are detailed in Table 1.

[0149] The PI 1 polymer synthesis protocol is repeated by adjusting the monomeric compositions, the amount of sodium hypophosphite and adding different amounts of α-cyclodextrin to obtain the P17 and P18 polymers, the compositions of which are detailed in Table 2.

[0150] The protocol for the synthesis of the Pli polymer is repeated except that the S4 solution of sodium hypophosphite comprises 168 g (25% by weight in water) of sodium hypophosphite and the Cl composition comprises 220.4 g of water and 56.1 g of sodium hypophosphite in order to obtain the P19 polymer.

[0151] In the examples, hypophosphite is used as a transfer agent. Its quantity is expressed in ppm relative to the weight of the monomers.

[0152] [Tables 1] Polymer Composition (%mol) Sodium Hypophosphite (ppm) Molecular Weight (g / mol) MAA NMA PI (Counterexample) 100 - 124918 12000 P2 (Invention) 99.5 0.5 249835 5000 P3 (Invention) 99.5 0.5 166558 9000 P4 (Invention) 99.5 0.5 124918 12000 P5 (Invention) 98.5 1.5 249835 5000 P6 (Invention) 98.5 1.5 166558 9000 P7 (Invention) 98.5 1.5 124918 12000 P8 (Invention) 973249 835 5,000 P9 (Invention) 97 3,166 558 9,000 P10 (Invention) 97 3,124 918 12,000 P11 (Invention) 94 6,249 835 5,000 P12 (Invention) 94 6,166 558 9,000 PI3 (Invention) 94 6,124 918 12,000 P14 (Invention) 90 10,270 000 3,600 P15 (Invention) 90 10,166 558 9,000 P16 (Counterexample) 85 15,300 000 2,200 P19 (Invention) 94 6,249 835 5 000

[0153] Table 1: Composition of PI polymers at P16 and P19

[0154] [Tables2] Polymer Composition (%mol) Sodium Hypophosphite (ppm) Molecular Weight (g / mol) MAA NMA α-Cyclodextrin PI7 (Invention) 99 0.5 0.5 - 9,000 PIS (Invention) 99 0.25 0.25 249 835 5,000

[0155] Table 2: Composition of polymers P17 and P18 * Tanning

[0156] Tanning Protocol A piece of sheepskin is cut to obtain a 10g sample with the following dimensions: 5cm x 10cm. In a beaker, a brine is prepared by mixing: * 89 g of water; * 10 g NaCl; * 1 g of sulfuric acid (96% by weight in water). The hide is immersed in the beaker containing the brine. 10 g of tanning agent (10 g of polymer in water solution) are added to the beaker and mixed until completely dissolved. The hide is left overnight without stirring, then air-dried for 24 hours. Measurement of shrinkage temperature

[0157] The sample of tanned skin is immersed in a water bath at 50°C, the temperature of the water bath is gradually increased (1°C / minute) until the skin sample has shrunk by 30% (approximately 3.5cm x 7cm). The temperature at which the skin sample reaches a shrinkage rate of 30% corresponds to the shrinkage temperature (Tr).

[0158] The tanning results with PI polymers at P19 are summarized in Table 3. For comparison, the shrinkage temperature of glutaraldehyde tanning is between 65°C and 70°C.

[0159] [Tables3] Tanning agent Tr CC ) PI (Counterexample) 60 P2 (Invention) 68 P3 (Invention) 67 P4 (Invention) 69 P5 (Invention) 67 P6 (Invention) 68 P7 (Invention) 68 P8 (Invention) 69 P9 (Invention) 68 P10 (Invention) 65 Ply (Invention) 66 P12 (Invention) 66 P13 (Invention) 64 P14 (Invention) 65 P15 (Invention) 65 P16 (Counterexample) 60 P17 (Invention) 71 PI8 (Invention) 69 P19 (Invention) 70 Glutaraldehyde 65-70

[0160] Table 3: Tanning Results

[0161] The tanning agents of the invention offer a new alternative to glutaraldehyde tanning while avoiding the latter's toxicity and without the risk of formaldehyde release. They allow for a higher shrinkage temperature compared to PI and P16 polymers.

Claims

Demands

1. Tanning agent consisting of a polymer of at least: - 0.01 to 12 mol% of N-methylol(meth)acrylamide; and - 50 to 99.99 mol% of at least one anionic hydrophilic monomer.

2. A tanning agent according to claim 1, characterized in that the anionic hydrophilic monomer is one or more monomers selected from the group consisting of: acrylic acid, methacrylic acid, dimethylacrylic acid, crotonic acid, maleic acid, fumaric acid, 3-acrylamido-3-methylbutanoic acid, vinylsulfonic acid, vinylphosphonic acid, allylsulfonic acid, methallylsulfonic acid, 2-methylidenepropane-1,3-disulfonic acid, 2-sulfoethyl methacrylate, sulfopropyl methacrylate, sulfopropylacrylate, allylphosphonic acid, ethylene glycol methacrylate phosphate, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 2-acrylamido-2-methylpropane disulfonic acid, 3-allyloxy-2-hydroxypropane sulfonic acid, diethylallylphosphonate, carboxyethyl acrylate, water-soluble salts of these monomers.

3. Tanning agent according to claim 1 or 2, characterized in that 30 to 100 mol% of the total anionic hydrophilic monomers included in the tanning agent are in salified form.

4. Tanning agent according to any one of claims 1 to 3, characterized in that the tanning agent comprises 500 to 500,000 ppm of a transfer agent, by weight, relative to the total weight of the monomers of the tanning agent.

5. Tanning agent according to any one of claims 1 to 4, characterized in that the tanning agent has a weight average molecular weight between 500 and 100,000 g / mol.

6. Process for preparing a tanning agent consisting of a polymer of at least: - 0.01 to 12 mol% of N-methylol(meth)acrylamide monomer; and - 50 to 99.99 mol% of at least one anionic hydrophilic monomer, the process comprising at least the successive steps: i) mixing the monomers with at least one polymerization initiator in a polar solvent; ii) radical polymerization of monomers to obtain the tanning agent.

7. The process according to claim 6, characterized in that the polymerization is a solution polymerization.

8. A process according to claim 6 or 7, characterized in that all the monomers constituting the tanning agent are cast during polymerization.

9. A process according to any one of claims 6 to 8, characterized in that the radical polymerization of the monomers is carried out in the presence of at least one transfer agent, 15 to 35% by weight of at least one transfer agent, relative to the total weight of transfer agent, being added during step i), and 65 to 85% by weight of at least one transfer agent, relative to the total weight of transfer agent, being poured throughout step ii).

10. A leather tanning process comprising contacting a hide with at least one tanning agent according to any one of claims 1 to c

11.

12. J. Leather obtained according to the process of claim 10. Process for manufacturing articles for leather goods, glove making, shoemaking, furniture or saddlery with the leather according to claim 11.