High molecular weight polymeric dispersions comprising homopolymeric dispersant made by controlled polymerization

Abstract

The invention relates to a method of manufacturing a polymeric dispersant for a water-in-water dispersion which polymeric dispersant is water soluble being made by the steps of polymerizing a monomeric composition comprising at least one (meth)acrylic monomer and destroying residual monomers after the step of polymerizing by adding an initiator, characterized in that the step of adding the initiator is performed at a defined temperature. Further, the invention relates to a polymeric dispersant obtained by a method according to the invention. Even further, the invention relates to a method of manufacturing the polymer dispersion, which method comprises the steps of providing a reaction mixture in an aqueous medium comprising the polymeric dispersant according to the invention and a monomer composition comprising radically polymerizable monomers, and subjecting the monomer composition in the reaction mixture to a radical polymerization to synthesize a dispersed polymer so as to form the polymer dispersion. These polymer dispersions are designated as water-in-water (w / w) polymer dispersions.

Description

[0001] HIGH MOLECULAR WEIGHT POLYME IC DISPERSIONS COMPRISING HOMOPOLYMERIC

[0002] DISPERSANT MADE BY CONTROLLED POLYMERIZATION

[0003] The invention relates to a method of manufacturing a polymeric dispersant for a water-in-water dispersion which polymeric dispersant is water soluble being made by the steps of polymerizing a monomeric composition comprising at least one (meth)acrylic monomer and destroying residual monomers after the step of polymerizing by adding an initiator, characterized in that the step of adding the initiator is performed at a defined temperature. Further, the invention relates to a polymeric dispersant obtained by a method according to the invention. Even further, the invention relates to a method of manufacturing the polymer dispersion, which method comprises the steps of providing a reaction mixture in an aqueous medium comprising the polymeric dispersant according to the invention and a monomer composition comprising radically polymerizable monomers, and subjecting the monomer composition in the reaction mixture to a radical polymerization to synthesize a dispersed polymer so as to form the polymer dispersion. These polymer dispersions are designated as water-in- water (w / w) polymer dispersions.

[0004] The foremost objective is to unlock the potential of water and renewable resources to build a safer, healthier, more sustainable world. Numberless industrial processes are water-based processes. The replacement of environmental harmful substances or their volume reduction in water-based processes form the basis towards more sustainable solutions. The invention aims at this foremost objective in the field of w / w polymer dispersions. The improvements of w / w polymer dispersions directly correlate with the sustainability in downstream applications, as e.g., in the paper making process. The better such w / w polymer dispersion work as additives in water-based processes, like in the paper making process, the less of such process additives are to be used. Furthermore, the substitution of hydrocarbons supports the foremost objective.

[0005] The w / w polymer dispersions are useful as flocculants, dewatering (drainage) aids and retention aids in papermaking besides applications in other technical fields. Paper is manufactured by firstly making an aqueous slurry of cellulosic fibers which slurry has a water content of more than 95 wt-%. The final paper sheet has a water content of less than 5 wt.-%. The dewatering (drainage) and retention represent crucial steps in papermaking and are important for an efficient paper making process. High- performance w / w polymer dispersions represent a key factor in the paper making process.

[0006] State of the art polymer dispersions are often stabilized by low molecular salts. An alternative makes use of a w / w polymer dispersion, which is produced by copolymerizing ethylenically unsaturated monomers in an aqueous system comprising a polymeric dispersant resulting in a dispersion comprising the polymeric dispersant and the synthesized copolymer. The US8476391 B2 and US7323510B2 represent early publications of such w / w polymer dispersions. It is well-accepted knowledge in this technical field that the addition of separately synthesized copolymers on the one hand and polymer dispersants on the other hand results in a product having completely different properties compared to the w / w polymer dispersions as disclosed in the above patent documents. It requires the copolymerization within a system comprising the polymeric dispersant in order to obtain high-performance flocculant products e.g. for the paper making process.

[0007] These circumstances make the manufacturing of the w / w polymer dispersions to a multi-parameter system. The kind of the ethylenically unsaturated monomer, their ratio, the molecular weight of the polymer dispersant are only a very few parameters influencing the properties of the w / w polymer dispersion. An improvement of the properties of the final product of the w / w polymer dispersion has been subject of numberless attempts in research and development.

[0008] One of the decisive parameters for beneficially influencing the properties of the w / w dispersions is the polymeric dispersant being one kind of polymer of the w / w dispersion besides the copolymer being polymerized in presence of the polymeric dispersant.

[0009] There is still the need for improving the polymeric dispersant intermediate product having a beneficial impact on complex polymer systems and offering the possibility to improve their properties. As such, there is still the need for improving the long-term stability and ensuring a long shelf-life under unfavorable circumstances like e. g. alternating temperatures.

[0010] Further, there have been identified challenges regarding the manufacturing process of the w / w polymer dispersion itself. It was observed that some batches showed instabilities during the manufacturing process. Some dispersions start to gel during the manufacturing process. Further, some of the products show instabilities sometime after completion of the manufacturing process. Such instabilities are supported e.g. by alternating temperature when shipped to the customer.

[0011] The invention’s underlaying problem relates to overcome the drawbacks of the state of the art. In particular, the invention’s underlaying problem relates to the provision of a polymeric dispersant exerting beneficial properties to w / w dispersions, in particular in terms of stability, long-term stability and handling of the w / w dispersions, in particular with regard to the viscosity of the w / w dispersions. Further, the invention’s underlaying problem relates to the provision of a process for manufacturing a w / w polymer dispersion resulting in a product ensuring improved properties in their use, in particular in paper making processes. Further, the invention’s underlaying problem relates to the provision of a process for manufacturing a w / w polymer dispersion ensuring a high degree of stability during the manufacturing process and ensuring a high shelf-life under unfavorable circumstances like e. g. alternating temperatures.

[0012] The invention’s underlaying problems are solved by the subject-matter of claim 1. Thus, according to a first aspect, the invention relates a method of manufacturing a polymeric dispersant for a water-in- water dispersion which polymeric dispersant is water soluble being made by the steps of polymerizing a monomeric composition comprising at least the following monomer of formula la

[0013] R1means hydrogen or methyl;

[0014] Zi is O, NH or NR4, wherein R4 means Ci-C4-alkyl, and Y is one of , where

[0015] Yo and Y1 are a C1-C6 alkylene group, optionally substituted with one or more hydroxy groups;

[0016] Y2, Y3, Ys, Ye, Y7, independently of each other, are each Ci-Ce-alkyl; and Z is a counterion; and destroying residual monomers after the step of polymerizing by adding an initiator, wherein the step of adding the initiator is performed at a temperature of 80°C or more.

[0017] The term “initiator” has its regular meaning in the field of organic chemistry, particularly polymer chemistry. That is, initiators are substances that are added to a reaction mixture to enable and start the desired reaction. In the present invention, the polymerization of the monomeric constituents is performed in a first step. This first step is a step of polymerization of monomeric constituents. After the first step, the residual monomers of the monomeric composition are destroyed. This is performed by adding an initiator. It is crucial that the step of destroying residual monomers is performed at a temperature of 80°C or more. As for the beneficial effect, it was surprisingly found that the subsequent method of manufacturing the w / w polymer dispersion can be performed without the risk of a steep increase in the viscosity. The polymerization in the first step result in a residual amount of monomers which have not reacted in the polymerization. The propagating chains find its termination before all monomers have been converted. If the destruction of the residual monomers is performed with an initiator below a temperature of 80°C or more, it was found in some instances that the polymer dispersion in the process of manufacturing the w / w polymer dispersion starts gelling. If the polymeric dispersant is manufactured in line with the method of the invention, this gelling is prevented.

[0018] According to preferred embodiments, the step of adding the initiator is performed at a temperature above 80°C and below 90°C, preferably above 81 °C and below 85°C. These temperature ranges give favorable solutions to the invention’s object in the above sense. It was believed in the state of the art that the temperature solely needs to be below a certain temperature. As for technical reasons, it reveals that the above temperature ranges have the herein described impact on the obtained product. In a preferred embodiment, the step of adding the initiator is performed within a time frame of 1 minute to 150 minutes from the time of reaching the maximum temperature Tmax, more preferred within a time frame of 20 minute to 120 minutes, even more preferred within a time frame of 30 minutes to 90 minutes. The maximum temperature Tmax is measured within the reaction mixture.

[0019] According to a preferred embodiment, the initiator is a radical initiator. More preferred, the radical initiator is a water-soluble radical initiator. Even more preferred, the radical initiator is selected from the group consisting of 2,2'-azobis-(2-amidinopropane) dihydrochloride, 4,4'-azobis-(4- cyanopentanoic acid), 2,2'-azobis(2-(-imidazolin-2-yl)propane dihydrochloride and mixtures thereof.

[0020] According to an alternative embodiment, the initiator is a system, such as ammonium persulfate / ferric sulfate. According to a further alternative embodiment, the initiator is an oil-soluble initiators, more preferred the initiator is represented by dibenzoyl peroxide, dilauryl peroxide or tert-butyl peroxide, or an azo compound, such as 2,2'-azobisisobutyronitrile, dimethyl 2,2'-azobisisobutyrate and 2,2'-azobis- (4-methoxy-2, 4-dimethylvaleronitrile). Preferred azo compounds are 2,2'-azobisisobutyronitrile, 2,2'- azobis(2-(-imidazolin-2-yl)propane dihydrochloride, 2,2'-azobis(2-aminopropane) dihydrochloride; or the radical initiator is preferably potassium persulfate, ammonium persulfate, hydrogen peroxide, optionally in combination with a reducing agent, e.g. an amine or sodium sulfite. The initiators may be used either individually or in combinations. However, the above disclosed water-soluble radical initiators are preferred compared to these alternative initiators.

[0021] According to a preferred embodiment, the monomeric composition further comprises (meth)acrylic acid and / or (meth)acrylic amide. In that case, the polymeric dispersant is a copolymer constituted by the monomeric constituent based on the monomer of formula la and the monomers (meth)acrylic acid and / or (meth)acrylic amide.

[0022] According to a preferred embodiment, the monomeric composition comprises a cationic monomer falling under formula la. According to a more preferred embodiment, the monomeric composition comprises at least one monomer of formula la, in which Zi is O, NH or NR4, preferably NH or NR4, wherein R4 means methyl; Y is , wherein

[0023] Y1 is ethylene or propylene, optionally substituted with one hydroxy group; Ys, Ye, Y7 are each methyl; and Z is a counterion selected from the group consisting of a halogen, pseudo-halogen, acetate, and SO4CH3-. The invention’s underlaying problems are further solved by the subject-matter of claim 6. Thus, according to a second aspect, the invention relates to a polymeric dispersant obtained by a method according to the invention.

[0024] It is perceived by a skilled person, that the method according to the invention leaves a “structural fingerprint” on the polymeric dispersant as the product. In other words, a polymeric dispersant being manufactured by a method different from the one of the invention results in a polymeric dispersant composition different from the one of the present invention. The polymeric dispersant manufactured in line with the present invention is favorable in the method of manufacturing the w / w polymer dispersion as described herein.

[0025] According to a preferred embodiment, the polymeric dispersant has a weight average molecular weight Mwas determined by size exclusion chromatography of 40.000 to less than 150.000 g / mol, preferred 50.000 to 140.000 g / mol, more preferred 60.000 to 130.000, most preferred 85.000 to 125.000 g / mol.

[0026] It was surprisingly found that polymeric dispersants of this polymer weights work beneficially in the method of manufacturing w / w polymer dispersions.

[0027] The monomeric composition mandatorily comprises a monomer of the above formula la. Preferably the monomer of the above formula la is a cationic monomer, which is more preferred selected from the group consisting of (alk)acrylamidoalkyltrialkyl ammonium halides (e.g., trimethylammonium- alkyl(meth)acrylamide halides), (alk)acryloyloxyalkyl trialkyl ammonium halides (e.g., trimethylammoniumalkyl(meth)acrylate halides), alkenyl trialkyl ammonium halides and dialkenyl dialkyl ammonium halides (e.g., diallyldialkylammonium halides). More preferably, the polymeric dispersant is a cationic polymer derived from a monomer composition comprising a cationic monomer selected from the group consisting of trimethylammonium-alkyl(meth)acrylate halides, trimethylammoniumalkyl(meth)acrylamide halides and diallyldialkylammonium halides. Preferably, the aforementioned cationic monomers comprise 6 to 25 carbon atoms, more preferably 7 to 20 carbon atoms, most preferably 7 to 15 carbon atoms and in particular 8 to 12 carbon atoms.

[0028] In a very preferred embodiment, the polymeric dispersant is a polymer comprising quaternized trimethylammonium-propyl acrylamide (DIMAPA quat).

[0029] According to a preferred embodiment, the polymeric dispersant is a cationic polymeric dispersant. It is particularly preferred that the polymeric dispersant is water soluble being made by polymerizing a monomeric composition comprising at least one monomer of the above item i. wherein Zi is O, NH or NR4, preferably NH or NR4, wherein R4 means methyl;

[0030] Y is

[0031] Y1 is ethylene or propylene, optionally substituted with one hydroxy group;

[0032] Ys, Ye, Y7 are each methyl; and

[0033] Z is a counterion selected from the group consisting of a halogen, pseudo-halogen, acetate, and SO4CH3-.

[0034] The invention’s underlaying problems are further solved by the subject-matter of claim 8. Thus, according to a third aspect, the invention relates to method for manufacturing a water-in-water polymer dispersion which comprises subjecting an aqueous reaction mixture to a radical polymerization reaction, which aqueous reaction mixture comprising (a) the polymeric dispersant according to the second aspect of the present invention, and (b) a monomer composition comprising one or more of the following: i. a non-ionic monomer of formula (I)

[0035] , where

[0036] R1means hydrogen or methyl;

[0037] R2and R3are, independently of each other, hydrogen, Ci-Cs-alkyl or Ci-Cs-hydroxyalkyl, ii. a cationic monomer of formula (II) , where

[0038] R1means hydrogen or methyl;

[0039] Zi is O, NH or NR4, wherein R4 means Ci-C4-alkyl, preferably methyl, and

[0040] Y is one of

[0041] Yo and Y1 are a Ci-Ce alkylene group, optionally substituted with one or more hydroxy groups, preferably ethylene or propylene, optionally substituted with one hydroxy group; Y2, Y3, Y5, Y6, Y7 independently of each other, are each Ci-Ce-alkyl, preferably methyl; and Z is a counterion, preferably a halogen, pseudo-halogen, acetate, or SO4CH3-; and Hi. an amphiphilic monomer of formulae (III) or (IV) nil;

[0042] , where

[0043] Zi is O, NH, NR4, wherein R4 means Ci-C4-alkyl, preferably methyl, R1 means hydrogen or methyl,

[0044] Rs is a Ci-Ce alkylene group, preferably ethylene or propylene,

[0045] R5 and Re are, independently of each other, each Ci-Ce-alkyl, preferably methyl, R7 is a C8-C32 alkyl, optionally substituted with one or more hydroxy groups, preferably C12- C20 alkyl, optionally substituted with one hydroxy group, and

[0046] Z is a counterion, preferably a halogen, pseudo-halogen, acetate, or SO4CH3-; or

[0047] TVs

[0048] Z1 is O, NH, NR4, wherein R4 means Ci-C4-alkyl, preferably methyl,

[0049] R1 means hydrogen or methyl,

[0050] R10 means hydrogen, C8-C32 alkyl, C8-C32 aryl and / or C8-C32 aralkyl, preferably C12-C20 alkyl, R9 is a Ci-Ce alkylene group, preferably an ethylene group or propylene group, n is an integer between 1 and 50, preferably between 2 and 30, more preferred 3 and 15, most preferred 4 and 8; and iv. an ethylenically unsaturated cross-linker containing 2, 3, 4 or 5 ethylenically unsaturated groups.

[0051] This method according to the third aspect of the present invention results in a w / w polymer dispersion. It has surprisingly been found that this method can reliably be performed without an unwanted steep increase in the viscosity due to a gelling of the reaction composition.

[0052] The method comprises the provision of a reaction mixture comprising the monomers to be copolymerized and the polymeric dispersant according to the first aspect. The monomers are polymerized in presence of the polymeric dispersant in an aqueous medium. It is mentioned herewith that the terms “monomeric composition” distinguishes from the term “monomer composition”. The monomeric composition is used to obtain the polymeric dispersant, and the monomer composition results in the copolymer being present in the w / w dispersion. According to well-established technical knowledge, a polymer dispersion obtained by the method according to the second aspect of the invention cannot be obtained in that the monomer composition is subjected to a copolymerization, whereupon, subsequently after the copolymerization, the polymeric dispersant is added. Unique properties are conferred to the polymer dispersion by applying the method according to the invention, which polymer dispersion represents the final product comprising the copolymer obtained from the radically polymerizable monomers together with the polymeric dispersant.

[0053] In the framework of the present invention, a cationic monomer is a monomer carrying permanently a positive charge.

[0054] According to the preferred embodiment, one or more of the above monomers given under items i. to iv. are used as monomers in the monomer composition to be polymerized. It is preferred that a copolymer is polymerized, i.e. that two of the above monomers given under items i. to iv. are provided for the monomer composition to be polymerized. It is preferred that one monomer of item i. and one monomer of item ii. are provided for the monomer composition subjected to the copolymerization. In a preferred embodiment, the radically polymerizable monomers comprise a radically polymerizable nonionic monomer according to general formula (I); and a radically polymerizable cationic monomer according to general formula (II). These monomers being copolymerized are beneficial for solving the above problems.

[0055] According to a preferred embodiment, the monomer composition contains at least the non-ionic monomer of formula (I) and the cationic monomer of formula (II). It is further preferred, that the nonionic monomer of formula (I) is acrylamide.

[0056] Even further, it is preferred that one monomer of item i. one monomer of item ii. and one monomer of item iv. are provided for the monomer composition subjected to the copolymerization.

[0057] In a preferred embodiment, the method is characterized in that the monomer composition comprising the radically polymerizable monomers at least comprises the non-ionic monomer of formula (I) being selected from those in which R1means hydrogen or methyl, and R2and R3are both hydrogen, hydrogen and C1-C3 alkyl, hydrogen and hydroxyethyl, or both C1-C3 alkyl, and / or the cationic monomer of formula (II) being selected from those in which R1means hydrogen or methyl, and Z1 is O, NH or NR4, wherein R4 means methyl, Y1 is C2-C6 alkylene, preferably ethylene or propylene, Ys, Ye and Y7 are all methyl, and Z is a halogen.

[0058] In a preferred embodiment, the radically polymerizable monomers comprise a radically polymerizable non-ionic monomer according to general formula (I) which is selected from the group consisting of (meth)acrylamide, N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N- ethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-methyl-N-ethyl(meth)-acrylamide, N- isopropyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide.

[0059] In another preferred embodiment, the radically polymerizable monomers comprise a radically polymerizable cationic monomer according to general formula (II) which is selected from the group consisting of trimethylammonium-C2-C6-alkyl(meth)acrylate halides, and trimethylammonium-C2-C6- alkyl(meth)acrylamide halides. In a most preferred embodiment, the monomer composition comprises a radically polymerizable monomer being (meth)acrylamide together with a radically polymerizable monomer selected from trimethylammonium-C2-C6-alkyl(meth)acrylate halides, in particular being an acryloyl oxyethyl trimethylammonium halide.

[0060] In the framework of this application, the term “halogen” or “halide” may be any acceptable halogen or halide as e.g. chloride, bromide or iodide; the counter ions of the salts may be any acceptable counter ions as e.g. halides, methosulfate, sulfate or others.

[0061] According to one embodiment, the monomer composition comprising radically polymerizable monomers comprises a cross-linker. Cross — linkers are known to the skilled person. In this preferred embodiment, the monomer composition preferably contains 0.0001 to 1 .25 wt.-% of one or more preferably ethylenically unsaturated cross-linkers, based on the total weight of monomers. If ethylenically unsaturated cross-linkers are present, they contain 2, 3, 4 or 5 ethylenically unsaturated groups that are radically polymerizable.

[0062] Examples of cross-linkers with two radically polymerizable ethylenically unsaturated groups include:

[0063] (1) Alkenyl di(meth)acrylates, such as 1 ,6-hexanediol di(meth)acrylate, 1 ,10-decanediol di(meth)acrylate, 1 ,12-dodecanediol di(meth)acrylate, 1 ,18-octadecanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, methylene di(meth)acrylate, 2,2’-bis(hydroxymethyl)-1 ,3- propanediol di(meth)acrylate, and preferably, ethylene glycol di(meth)acrylate, 1 .3-propane-diol di(meth)acrylate, 1 ,3-butanediol di(meth)acrylate, and 1 ,4-butanediol di(meth)acrylate;

[0064] (2) Alkylene di(meth)acrylamides, e.g. N-methylene di(meth)acrylamide, N,N'-3-methyl-butylidene bis(meth)acrylamide, N,N'-(1 ,2-dihydroxyethylene) bis(meth)acrylamide, and preferably N,N'- hexamethylene bis(meth)acrylamide, and particularly preferably N,N'-methylene bis(meth)acrylamide;

[0065] (3) Polyalkoxydi(meth)acrylates according to general formula (V) where

[0066] R10is hydrogen or methyl;

[0067] R11is selected from -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2- or -CH2CH2CH2CH2CH2CH2-; and m is an integer in the range 2-50. Examples of cross-linkers according to general formula (V) include polypropylene glycol di(meth)acrylates with m in the range 4-25; polybutylene glycol di(meth)acrylates with m in the range 5-40; and, preferably, polyethylene glycol di(meth)acrylates with m in the range 2-45, e.g. diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate; and, more preferably, polyethylene glycol di(meth)acrylates with m inthe range 5-20;

[0068] (4) Examples of additional di(meth)acrylates which may be used include benzylidene di-(meth)- acrylate, bisphenol-A di(meth)acrylate, 1 ,3-di(meth)acryloyloxy-Z-propanol, hydro-quinone di(meth)acrylate, ethanedithiol di(meth)acrylate, propanedithiol di(meth)acrylate, polyethylene dithiol di(meth)acrylate, and polypropylene dithiol di(meth)acrylate;

[0069] (5) Divinyl compounds, for example, 1 ,4-butanediol divinyl ether, divinylbenzene, butadiene, 1 ,6- hexadiene; di(meth)a| ly I compounds, such as, for example, di(meth)allyl phthalate or di(meth)ally I succinate; vinyl (meth)acrylic compounds, for example, vinyl (meth)acrylate; or preferably (meth)allyl (meth)acrylic compounds, for example, allyl (meth)acrylate.

[0070] Examples of cross-linkers having 3 or more ethylenically unsaturated radically polymerizable groups include glycerin tri(meth)acrylate, 2, 2-dihydroxymethyl-1 -butanol tri(meth)acrylate, trimethylolpropane triethoxy tri(meth)acrylate, trimethacrylamide, (meth)allylidene di(meth)-acrylate, 3-allyloxy-1 ,2- propanediol di(meth)acrylate, triallyl amine, triallyl cyanurate or triallyl isocyanurate; and also (as representative compounds with more than 3 ethylenically unsaturated radically polymerizable groups) pentaerythritol tetra(meth)acrylate and N,N,N'N'-tetra(meth)acryloyl-1 ,5-pentanediamine.

[0071] An example of a cross-linker having 5 ethylenically unsaturated radically polymerizable groups is dipentaerithritol-pentaacrylate.

[0072] Particularly preferred cross-linkers are selected from the group constsiting of methylene bisacrylamide, polyethylene glycol diacrylate and triallylamine.

[0073] Further preferred cross-linkers include asymmetrically cross-linkable monomers, i.e. cross-linkable monomers which rely on different functional groups with respect to the incorporation reaction into the polymer backbone and the cross-linking reaction. Examples of such asymmetrically cross-linkable monomers include N'-methylol acrylamide, N'-methylol methacrylamide and glycidyl(meth)acrylate.

[0074] Cross-linkers of this type have the advantage that cross-linking may be initiated subsequently. Thus, cross-linking may be performed under different conditions than the radical polymerization of the main- backbone. Preferably, cross-linking is initiated after changing the reaction conditions, 6.9. the pH value (addition of acid or base), the temperature, and the like. Optionally, the monomer composition further comprises a hydrophobic monomer, preferably a hydrophobic (meth)acrylic acid C4-18-alkyl ester; and / or an ethylenically unsaturated monomer. In a preferred embodiment, the method is characterized in that the radically polymerizable monomers are selected from the non-ionic monomer of formula (I) and / or the cationic monomer of formula (II), wherein the amount of the radically polymerizable monomers being selected from the non-ionic monomer of formula (I) and / or the cationic monomer of formula (II) is between 80 and less than 100 wt-%, preferred 85 and 99 wt-%, most preferred 90 and 95 wt-% based on the total amount of radically polymerizable monomers, wherein the remainder is selected from the group consisting of any other ethylenically polymerizable monomer, a monomer of formula (III), a monomer of formula (IV), and the ethylenically unsaturated cross-linker containing 2, 3, 4 or 5 ethylenically unsaturated groups.

[0075] In this regard, the sum of the values in wt-% needs not to amount to 100 wt-%, since further ethylenically unsaturated monomers besides the monomers of formulae (I) and / or (II) may be contained in the monomer composition, i.e. in the reaction mixture, which have to be taken into account when determining the total amount of monomers. In one preferred embodiment, however, the monomer composition consists of monomers (a) and (b) so that the sum of the two values in wt-% amounts to 100 wt-%, i.e. no further monomers are present.

[0076] In a preferred embodiment, the monomer composition comprises at least 5 wt.-%, preferably at least 20 wt.-% of the non-ionic monomer of formula (I)

[0077] (1)

[0078] R1means hydrogen or methyl;

[0079] R2and R3are, independently of each other, hydrogen, Ci-Cs-alkyl or Ci-Cs-hydroxyalkyl; at least 5 wt.-%, preferably at least 20 wt.-%, more preferred 25 to 47 wt.-%, most preferred 50.5 to 80 wt.-%, of the cationic monomer of formula (II) i'll? , where

[0080] R1means hydrogen or methyl;

[0081] Zi is O, NH or NR4, wherein R4 means Ci-C4-alkyl, preferably methyl, and

[0082] Y is one of , w .here Yo and Yi are a Ci-Ce alkylene group, optionally substituted with one or more hydroxy groups, preferably ethylene or propylene, optionally substituted with one hydroxy group;

[0083] Y2, Y3, Y5, Y6, Y7 independently of each other, are each Ci-Ce-alkyl, preferably methyl; and

[0084] Z is a counterion, preferably a halogen, pseudo-halogen, acetate, or SO4CH3 ;

[0085] 0.0001 to 1.25 wt.-%, preferably 0.0005 to 1 wt.-% of the ethylenically unsaturated cross-linker containing 2, 3, 4 or 5 ethylenically unsaturated groups; and optionally, further ethylenically unsaturated monomers.

[0086] In this regard again, the sum of the values in wt-% needs not to amount to 100 wt-%, since further ethylenically unsaturated monomers besides the monomers of formulae (I) and / or (II) may be contained in the monomer composition, i.e. in the reaction mixture, which have to be taken into account when determining the total amount of monomers. In one preferred embodiment, however, the monomer composition consists of monomers (a) and (b) so that the sum of the two values in wt-% amounts to 100 wt-%, i.e. no further monomers are present.

[0087] In the present application, all percentages with regard to the monomer composition are based on the total amount of monomers used in the copolymerization. The percentages with regard to the monomeric composition are based on the total amount of monomers used to produce the polymeric dispersant.

[0088] In a preferred embodiment, the method is characterized in that the viscosity of the polymer dispersion amounts to 1 .800 mPas to less than 6.700 mPas , preferably 2.000 mPas to 6.000 mPas, more preferred 2.200 mPas to 5.500 mPas, most preferred 2.500 mPas to 5.000 mPas, as measured with a Brookfield viscometer with spindle 4 at 20°C and an angle speed of 10 rpm.

[0089] The viscosity is preferably the bulk viscosity which refers to the viscosity right after having obtained the cooled down product.

[0090] According to a preferred embodiment, the ratio of the polymeric dispersant to the dispersed polymer in the polymer dispersion is in the range of 0.45 : 1 to 1 : 0.9, preferred in the range of 0.5 : 1 to 1 : 1 , more preferred in the range of 0.55 : 1 to less than 1 : 1 , even more preferred in the range of 0.6 : 1 to 0.99 : 1 , in particular in the range of 0.65 : 1 to 0.9 : 1 .

[0091] The invention is in particular efficient if the method is characterized in that the total weight of the polymeric dispersant based on the total weight of the polymer dispersion is in the range of 10 to 28 wt.-%, preferred 12 to 26 wt.%, more preferred 14 to 24 wt.-%, even more preferred 16 to 22 wt.-%. According to a further embodiment, the method is characterized in that the total weight of the polymeric dispersant based on the total weight of the polymer dispersion is between 18 and 26 wt.-%, preferred 19 to 25 wt.-%. According to a further preferred embodiment, the method is characterized in that the monomer composition does not contain any hydrophobic monomers.

[0092] The invention’s underlaying problems are further solved by the subject-matter of claim 12. Thus, according to a fourth aspect, the invention relates to a water-in-water polymer dispersion comprising

[0093] (a) the polymeric dispersant according to the second aspect of the present invention, and

[0094] (b) a copolymer derived from a monomer composition comprising one or more of the following: i. a non-ionic monomer of formula (I)

[0095] «' 11

[0096] R1means hydrogen or methyl;

[0097] R2and R3are, independently of each other, hydrogen, Ci-Cs-alkyl or C1-C5- hydroxyalkyl, ii. a cationic monomer of formula (II)

[0098] (IB

[0099] R1means hydrogen or methyl;

[0100] Z1 is O, NH or NR4, wherein R4 means Ci-C4-alkyl, preferably methyl, and Y is one of

[0101] Yo and Y1 are a C1-C6 alkylene group, optionally substituted with one or more hydroxy groups, preferably ethylene or propylene, optionally substituted with one hydroxy group;

[0102] Y2, Y3, Y5, Y6, Y7 independently of each other, are each Ci-Ce-alkyl, preferably methyl; and

[0103] Z is a counterion, preferably a halogen, pseudo-halogen, acetate, or SO4CH3-; and

[0104] Hi. an amphiphilic monomer of formulae (III) or (IV) am

[0105] , where

[0106] Zi is O, NH, NR4, wherein R4 means Ci-C4-alkyl, preferably methyl,

[0107] R1 means hydrogen or methyl,

[0108] Rs is a Ci-Ce alkylene group, preferably ethylene or propylene,

[0109] R5 and Re are, independently of each other, each Ci-Ce-alkyl, preferably methyl,

[0110] R7 is a C8-C32 alkyl, optionally substituted with one or more hydroxy groups, preferably C12-C20 alkyl, optionally substituted with one hydroxy group, and Z is a counterion, preferably a halogen, pseudo-halogen, acetate, or SO4CH3-; or iJV)

[0111] Zi is O, NH, NR4, wherein R4 means Ci-C4-alkyl, preferably methyl,

[0112] R1 means hydrogen or methyl,

[0113] R10 means hydrogen, C8-C32 alkyl, C8-C32 aryl and / or C8-C32 aralkyl, preferably C12-C20 alkyl,

[0114] R9 is a Ci-Ce alkylene group, preferably an ethylene group or propylene group, and n is an integer between 1 and 50, preferably between 2 and 30, more preferred 3 and 15, most preferred 4 and 8; and iv. an ethylenically unsaturated cross-linker containing 2, 3, 4 or 5 ethylenically unsaturated groups.

[0115] According to a preferred embodiment, the polymer dispersion is obtained by a method for manufacturing the polymer dispersion wherein the polymeric dispersant has a weight average molecular weight Mwas determined by size exclusion chromatography of 40.000 to less than 150.000 g / mol, preferred 50.000 to 140.000 g / mol, more preferred 60.000 to 130.000, most preferred 85.000 to 120.000 g / mol.

[0116] According to a preferred embodiment, the polymer dispersion is obtained by a method for manufacturing the polymer dispersion wherein the polymer dispersion has a bulk viscosity below 6.700 mPas, preferably below 6.000 mPas, more preferred below 5.500 mPas, most preferred below 5.000 mPas as measured at 20°C with a Brookfield viscometer with spindle 4 and a speed of 10 rpm. The invention’s underlaying problems are further solved by the subject-matter of claim 13. Thus, according to a fifth aspect, the invention relates to a water-in-water polymer dispersion the water-in- water polymer dispersion is obtained by a method according to the third aspect of the invention.

[0117] The invention’s underlaying problems are further solved by the subject-matter of claim 14. Thus, according to a sixth aspect, the invention relates to the use of the polymer dispersion according to fourth and fifth aspect of the invention a. as a flocculant in the sedimentation, flotation or filtration of solids, b. as a thickener, c. as a contaminant control, d. as a dry strength aid; e. or retention agent or drainage aid in papermaking.

[0118] Features relating to preferred embodiments of the first aspect of the present invention, which are solely disclosed relating to the first aspect of the invention represent features of preferred embodiments of the second, third, fourth, fifth, and sixth embodiment as well. Features relating to preferred embodiments of the second aspect of the present invention, which are solely disclosed relating to the second aspect of the invention represent features of preferred embodiments of the first, third, fourth, fifth, and sixth embodiment as well. Features relating to preferred embodiments of the third aspect of the present invention, which are solely disclosed relating to the third aspect of the invention represent features of preferred embodiments of the first, second, fourth, fifth, and sixth embodiment as well.

[0119] In the following, exemplary embodiments (A) to (F) are disclosed which represent particularly preferred embodiments.

[0120] (A)

[0121] Method of manufacturing a polymeric dispersant for a water-in-water dispersion which polymeric dispersant is water soluble being made by the steps of polymerizing a monomeric composition comprising at least the following monomer of formula la

[0122] R1means hydrogen or methyl; Zi is O, NH or NR4, wherein R4 means Ci-C4-alkyl, and

[0123] Y is one of , where

[0124] Yo and Y1 are a C1-C6 alkylene group, optionally substituted with one or more hydroxy groups;

[0125] Y2, Y3, Y5, Ye, Y7, independently of each other, are each Ci-Ce-alkyl; and

[0126] Z is a counterion; destroying residual monomers after the step of polymerizing by adding an initiator, characterized in that the step of adding the initiator is performed at a temperature of 80°C or more and below 90°C, preferably above 81 °C and below 85°C.

[0127] (B)

[0128] Method of manufacturing a polymeric dispersant for a water-in-water dispersion which polymeric dispersant is water soluble being made by the steps of polymerizing a monomeric composition comprising at least the following monomer of formula la (la), where

[0129] R1means hydrogen or methyl;

[0130] Z1 is O, NH or NR4, wherein R4 means Ci-C4-alkyl, and

[0131] Y is one of

[0132] Yo and Y1 are a Ci-Ce alkylene group, optionally substituted with one or more hydroxy groups;

[0133] Y2, Y3, Ys, Ye, Y7, independently of each other, are each Ci-Ce-alkyl; and

[0134] Z is a counterion; destroying residual monomers after the step of polymerizing by adding an initiator, characterized in that the step of adding the initiator is performed at a temperature of 80°C or more and below 90°C, preferably above 81 °C and below 85°C, wherein the step of adding the initiator is performed within a time frame of 0 seconds to 60 minutes from the time of reaching the maximum temperature Tmax, more preferred within a time frame of 1 minute to 30 minutes, even more preferred within a time frame of 5 minutes to 15 minutes.

[0135] (C) Method of manufacturing a polymeric dispersant for a water-in-water dispersion which polymeric dispersant is water soluble being made by the steps of polymerizing a monomeric composition comprising at least the following monomer of formula la (la), where

[0136] R1means hydrogen or methyl;

[0137] Zi is O, NH or NR4, wherein R4 means Ci-C4-alkyl, and

[0138] Y is one of

[0139] Yo and Y1 are a C1-C6 alkylene group, optionally substituted with one or more hydroxy groups;

[0140] Y2, Y3, Ys, Ye, Y7, independently of each other, are each Ci-Ce-alkyl; and

[0141] Z is a counterion; destroying residual monomers after the step of polymerizing by adding an initiator, characterized in that the step of adding the initiator is performed at a temperature of 80°C and below 85°C, wherein the initiator is a radical initiator, preferably 2,2'-Azobis(2-amidinopropane) dihydrochloride, 4,4'-azobis-(4-cyanopentanoic acid), 2,2'-azobis(2-(-imidazolin-2-yl)propane dihydrochloride and mixtures thereof, in particular 2, 2'-azobis(2-amidinopropane) dihydrochloride.

[0142] (D)

[0143] Method of manufacturing a polymeric dispersant for a water-in-water dispersion which polymeric dispersant is water soluble being made by the steps of polymerizing a monomeric composition comprising at least one of a (meth)acryloyl amidopropyl trimethylammonium salt or a (meth)acryloyl oxyethyl trimethylammonium salt; destroying residual monomers after the step of polymerizing by adding an initiator, wherein the step of adding the initiator is performed at a temperature above 80°C and below 85°C.

[0144] (E)

[0145] Method for manufacturing a water-in-water polymer dispersion which comprises subjecting an aqueous reaction mixture to a radical polymerization reaction, which aqueous reaction mixture comprising

[0146] (a) the polymeric dispersant made by a method of manufacturing a polymeric dispersant for a water- in-water dispersion which polymeric dispersant is water soluble being made by the steps of polymerizing a monomeric composition comprising at least the following monomer of formula la (la), where

[0147] R1means hydrogen or methyl;

[0148] Zi is O, NH or NR4, wherein R4 means Ci-C4-alkyl, and

[0149] Y is one of , where

[0150] Yo and Y1 are a Ci-Ce alkylene group, optionally substituted with one or more hydroxy groups;

[0151] Y2, Y3, Ys, Ye, Y7, independently of each other, are each Ci-Ce-alkyl; and

[0152] Z is a counterion; destroying residual monomers after the step of polymerizing by adding an initiator, wherein the step of adding the initiator is performed at a temperature of 80°C or more and below

[0153] 90°C, preferably above 81 °C and below 85°C, and

[0154] (b) a monomer composition comprising one or more of the following: i. a non-ionic monomer of formula (I)

[0155] R1means hydrogen or methyl;

[0156] R2and R3are, independently of each other, hydrogen, Ci-Cs-alkyl or Ci-Cs-hydroxyalkyl, ii. a cationic monomer of formula (II)

[0157] (111

[0158] R1means hydrogen or methyl;

[0159] Z1 is O, NH or NR4, wherein R4 means Ci-C4-alkyl, preferably methyl, and

[0160] Y is one of , where

[0161] Yo and Yi are a Ci-Ce alkylene group, optionally substituted with one or more hydroxy groups, preferably ethylene or propylene, optionally substituted with one hydroxy group; Y2, Y3, Y5, Y6, Y7 independently of each other, are each Ci-Ce-alkyl, preferably methyl; and Z is a counterion, preferably a halogen, pseudo-halogen, acetate, or SO4CH3-; and iv. an ethylenically unsaturated cross-linker containing 2, 3, 4 or 5 ethylenically unsaturated groups.

[0162] (F)

[0163] Method for manufacturing a water-in-water polymer dispersion which comprises subjecting an aqueous reaction mixture to a radical polymerization reaction, which aqueous reaction mixture comprising

[0164] (a) the polymeric dispersant made by a method of manufacturing a polymeric dispersant for a water- in-water dispersion which polymeric dispersant is water soluble being made by the steps of polymerizing a monomeric composition comprising at least one of a (meth)acryloyl amidopropyl trimethylammonium salt or a (meth)acryloyl oxyethyl trimethylammonium salt; destroying residual monomers after the step of polymerizing by adding an initiator, preferably a radical initiator, most preferred 2,2'-Azobis(2-amidinopropane) dihydrochloride, wherein the step of adding the initiator is performed at a temperature of 80°C or more and 85°C or below; and

[0165] (b) a monomer composition comprising a radically polymerizable non-ionic monomer according to general formula (I) which is selected from the group consisting of (meth)acrylamide, N- methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-ethyl(meth)acrylamide, N,N- diethyl(meth)acrylamide, N-methyl-N-ethyl(meth)-acrylamide, N-isopropyl(meth)acrylamide, and N- hydroxyethyl(meth)acrylamide; and / or a radically polymerizable cationic monomer according to general formula (II) which is selected from the group consisting of trimethylammonium-C2-C6- alkyl(meth)acrylate halides, and trimethylammonium-C2-C6-alkyl(meth)acrylamide halides. In a most preferred embodiment, the monomer composition comprises a radically polymerizable monomer being (meth)acrylamide together with a radically polymerizable monomer selected from trimethylammonium-C2-C6-alkyl(meth)acrylate halides, in particular being an acryloyl oxyethyl trimethylammonium halide.

[0166] EXAMPLES

[0167] In the following, the applied test methods are described in detail:

[0168] The bulk viscosity is measured as follows:

[0169] Use the product directly for the measurement. The spindle No. 4 is slowly immersed into the product and the viscosity determined with a Brookfield RVT viscometer at 10 rpm. The measurement is terminated when the reading remains constant for a period of 30 sec.

[0170] The molecular mass is measured as follows:

[0171] The molar mass is measured via Size Exclusion Chromatography (SEC). The measurement is in particular performed for the determination of the molecular weight of the dispersant.

[0172] The molecular weights are characterized via aqueous SEC using Pullulan standards for the calibration.

[0173] Sample Preparation:

[0174] The samples are diluted with the eluent (polymer make-down in a measuring flask) and filtered through a 1 pm filter (M&N) (via syringe) before they are injected.

[0175] If the machine is equipped with an autosampler filter the solution through a 1 pm filter into a vial. Used parameters: apparatus: SEC (Agilent) column: Novema 3000 (PSS) detector: Rl eluent: 1 .5 wt% formic acid in water flow rate: 1 ml / min calibration standards: pullulan with different Mw

[0176] The following examples further illustrate the invention but are not to be construed as limiting its scope.

[0177] Example 1 : Synthesis of the polymeric dispersant:

[0178] At first, 294.06 g water, 666.7 g acryloyl amidopropyl trimethylammonium chloride (DIMAPA quat.) (60wt%) and sulfuric acid (50wt%) to adjust the pH to 5.0 ± 0.2 were weighed in a 2 L vessel. Then the monomer solution was sparged with nitrogen for 30 min by stirring. Subsequently, the aqueous solution was heated up to 65 °C and quaternized N-[3-(dimethylamino)propyl]-3-{[3-(dimethylamino)propyl](2-{[3-(dimethylamino)- propyl]carbamoyl}ethyl)amino}propenamide and V-50 (2,2'-Azobis(2-amidinopropane) dihydrochloride) were added to the solution. After reaching Tmax, the vessel is cooled down to 80°C. Then, two additional portions of initiator (V-50) were given to the product in between 10 min for residual monomer burn out. The product was stirred for 1 h at 70°C. The final aqueous product was cooled down to 30°C. The dispersants were provided in 40 wt.-% aqueous solutions.

[0179] Example 2: Synthesis of polymer dispersion (charge density 15 mole%)

[0180] In a discontinuous process (batch size 1 ,000 kg), acrylamide and acryloyl oxyethyl trimethylammonium chloride (ADAME quat.) were polymerized in an aqueous solution in the presence of acryloyl amidopropyl trimethylammonium chloride (polymeric dispersant of Example 1). The water-phase was prepared at 200 rpm.

[0181] Firstly, 206.90 kg soft water, 261.80 kg Bio-acryl amide (49 wt.-%), 77.20 kg acryloyl oxyethyl trimethylammonium chloride (ADAME quat) (80 wt%), 412.50 kg polymeric dispersant of Example 1 , 10.00 kg ammonium sulphate and 0.20 kg Trilon C were loaded into the reaction vessel. The pH value was adjusted to pH 5.0±0.2 with approximately 0.10 kg of sulphuric acid (50 %). The vessel was evacuated five times before being aerated with nitrogen. The initiator composition was added at a negative pressure of 0.5 bar and maximum agitator speed. Initiating started at 22±1 °C with the addition of 0.34 kg V-50 in 3.05 kg soft water, 0.025 kg sodium persulfate in 0.47 kg soft water, 0.014 kg sodium bisulfite in 0.27 kg soft water, and 0.003 kg f-butylhydroperoxide (70 %) in 1 kg soft water. Afterwards the vessel was aerated again with nitrogen. After reaching the maximum temperature, a solution of 0.17 kg V-50 in 1 .53 kg soft water was added to reduce the monomer content. After a one-hour post reaction time, the product was cooled down to a temperature below 40°C. Then, 8.30 kg citric acid and 0.82 kg of the biocide Acticide SPX were added and the product was cooled down to a temperature below 30°C.

[0182] The w / w polymer dispersions 1 and 2 have been prepared in lab size: In a first example, the elimination of additional monomers (i.e. burnout) have been conducted at 60°C. In a second example, the burnout has been performed at 80°C. Initiated by an energy input by stirring, the viscosity makes a steep increase in the first example, i.e. when the burnout temperature is below 80°C. Even without initiation by energy input, the viscosity rises with time. The plant scale examples show the same effect: If burnout temperature is below 80°C as in the batches 2837092, 2839857, 2823287, 2840486, 2840334, and 2839862, the viscosity increases. The rate of the viscosity increase is higher if initiation by energy input is performed. If the burnout temperature amounts to 80°C, the product is stable as given by the constant viscosity over time.

Claims

Claims1 . Method of manufacturing a polymeric dispersant for a water-in-water dispersion which polymeric dispersant is water soluble being made by the steps of- polymerizing a monomeric composition comprising at least the following monomer of formula laR1means hydrogen or methyl;Zi is O, NH or NR4, wherein R4 means Ci-C4-alkyl, andY is one ofYo and Y1 are a C1-C6 alkylene group, optionally substituted with one or more hydroxy groups;Y2, Y3, Ys, Ye, Y7, independently of each other, are each Ci-Ce-alkyl; and Z is a counterion;- destroying residual monomers after the step of polymerizing by adding an initiator, characterized in that the step of adding the initiator is performed at a temperature of 80°C or more.

2. Method according to claim 1 , characterized in that the step of adding the initiator is performed at a temperature above 80°C and below 90°C, preferably above 81 °C and below 85°C.

3. Method according to claim 1 or claim 2, characterized in that the initiator is a radical initiator, preferably 2,2'-Azobis(2-amidinopropane) dihydrochloride, 4,4'-azobis-(4-cyanopentanoic acid), 2,2'-azobis(2-(-imidazolin-2-yl)propane dihydrochloride and mixtures thereof, in particular 2,2'- azobis(2-amidinopropane) dihydrochloride.

4. Method according to any one of claims 1 to 3, characterized in that the monomeric composition further comprises (meth)acrylic acid and / or (meth)acrylic amide.

5. Method according to any one of claims 1 to 4, characterized in that the monomeric composition comprises a cationic monomer falling under formula la, preferably characterized in that themonomeric composition comprises at least one monomer of formula la, in which Zi is O, NH or NR4, preferably NH or NR4, wherein R4 means methyl;Y isY1 is ethylene or propylene, optionally substituted with one hydroxy group;Ys, Ye, Y7 are each methyl; andZ is a counterion selected from the group consisting of a halogen, pseudo-halogen, acetate, and SO4CH3-.

6. Polymeric dispersant obtained by a method according to any one of claims 1 to 5.

7. Polymeric dispersant according to claim 6, characterized in that the polymeric dispersant has a weight average molecular weight Mwas determined by size exclusion chromatography of 40.000 to less than 150.000 g / mol, preferred 50.000 to 140.000 g / mol, more preferred 60.000 to 130.000, most preferred 85.000 to 125.000 g / mol.

8. Method for manufacturing a water-in-water polymer dispersion which comprises subjecting an aqueous reaction mixture to a radical polymerization reaction, which aqueous reaction mixture comprising(a) the polymeric dispersant according to claim 6 or claim 7, and(b) a monomer composition comprising one or more of the following: i. a non-ionic monomer of formula (I), whereR1means hydrogen or methyl;R2and R3are, independently of each other, hydrogen, Ci-Cs-alkyl or C1-C5- hydroxyalkyl, ii. a cationic monomer of formula (II), whereR1means hydrogen or methyl;Z1 is O, NH or NR4, wherein R4 means Ci-C4-alkyl, preferably methyl, andY is one ofYo and Yi are a Ci-Ce alkylene group, optionally substituted with one or more hydroxy groups, preferably ethylene or propylene, optionally substituted with one hydroxy group;Y2, Y3, Y5, Y6, Y7 independently of each other, are each Ci-Ce-alkyl, preferably methyl; andZ is a counterion, preferably a halogen, pseudo-halogen, acetate, or SO4CH3-; andHi. an amphiphilic monomer of formulae (III) or (IV) ilHs, whereZi is O, NH, NR4, wherein R4 means Ci-C4-alkyl, preferably methyl,R1 means hydrogen or methyl,Rs is a Ci-Ce alkylene group, preferably ethylene or propylene,R5 and Re are, independently of each other, each Ci-Ce-alkyl, preferably methyl,R7 is a C8-C32 alkyl, optionally substituted with one or more hydroxy groups, preferably C12-C20 alkyl, optionally substituted with one hydroxy group, and Z is a counterion, preferably a halogen, pseudo-halogen, acetate, or SO4CH3-; or{IV?Z1 is O, NH, NR4, wherein R4 means Ci-C4-alkyl, preferably methyl,R1 means hydrogen or methyl,R10 means hydrogen, C8-C32 alkyl, C8-C32 aryl and / or C8-C32 aralkyl, preferably C12-C20 alkyl,R9 is a Ci-Ce alkylene group, preferably an ethylene group or propylene group, n is an integer between 1 and 50, preferably between 2 and 30, more preferred 3 and 15, most preferred 4 and 8; andiv. an ethylenically unsaturated cross-linker containing 2, 3, 4 or 5 ethylenically unsaturated groups.

9. Method according to claim 8, characterized in that the monomer composition contains at least the non-ionic monomer of formula (I) and the cationic monomer of formula (II).

10. Method according to claim 8 or claim 9, characterized in that the non-ionic monomer of formula (I) is acrylamide.11 . Method according to any one of claims 8 to 10, characterized in that the ethylenically unsaturated cross-linker containing 2, 3, 4 or 5 ethylenically unsaturated groups is a crosslinker containing 2 or 3 ethylenically unsaturated groups being preferably selected from the group consisting of methylene bisacrylamide, polyethylene glycol diacrylate and triallylamine.

12. Water-in-water polymer dispersion comprising(a) the polymeric dispersant according to claim 6 or 7, and(b) a copolymer derived from a monomer composition comprising one or more of the following: i. a non-ionic monomer of formula (I), whereR1means hydrogen or methyl;R2and R3are, independently of each other, hydrogen, Ci-Cs-alkyl or C1-C5- hydroxyalkyl, ii. a cationic monomer of formula (II)I'HJ, whereR1means hydrogen or methyl;Z1 is O, NH or NR4, wherein R4 means Ci-C4-alkyl, preferably methyl, andY is one of, whereYo and Yi are a Ci-Ce alkylene group, optionally substituted with one or more hydroxy groups, preferably ethylene or propylene, optionally substituted with one hydroxy group;Y2, Y3, Y5, Y6, Y7 independently of each other, are each Ci-Ce-alkyl, preferably methyl; andZ is a counterion, preferably a halogen, pseudo-halogen, acetate, or SO4CH3-; andHi. an amphiphilic monomer of formulae (III) or (IV) a, whereZi is O, NH, NR4, wherein R4 means Ci-C4-alkyl, preferably methyl,R1 means hydrogen or methyl,Rs is a Ci-Ce alkylene group, preferably ethylene or propylene,R5 and Re are, independently of each other, each Ci-Ce-alkyl, preferably methyl,R7 is a C8-C32 alkyl, optionally substituted with one or more hydroxy groups, preferably C12-C20 alkyl, optionally substituted with one hydroxy group, and Z is a counterion, preferably a halogen, pseudo-halogen, acetate, or SO4CH3-; or nvs, whereZ1 is O, NH, NR4, wherein R4 means Ci-C4-alkyl, preferably methyl,R1 means hydrogen or methyl,R10 means hydrogen, C8-C32 alkyl, C8-C32 aryl and / or C8-C32 aralkyl, preferably C12-C20 alkyl,R9 is a Ci-Ce alkylene group, preferably an ethylene group or propylene group, and n is an integer between 1 and 50, preferably between 2 and 30, more preferred 3 and 15, most preferred 4 and 8; and iv. an ethylenically unsaturated cross-linker containing 2, 3, 4 or 5 ethylenically unsaturated groups.

13. Water-in-water polymer dispersion, characterized in that the water-in-water polymer dispersion is obtained by a method according to any one of claims 8 to 11 .T14. Use of the polymer dispersion according to claim 12 or claim 13• as a flocculant in the sedimentation, flotation or filtration of solids,• as a thickener,• as a contaminant control,• as a dry strength aid;• or retention agent or drainage aid in papermaking.

Images