Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/44—Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F120/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
  • C08F120/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F120/04—Acids; Metal salts or ammonium salts thereof
  • C08F120/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/01—Processes of polymerisation characterised by special features of the polymerisation apparatus used
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium
  • C08F2/22—Emulsion polymerisation
  • C08F2/24—Emulsion polymerisation with the aid of emulsifying agents
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/04—Acids; Metal salts or ammonium salts thereof
  • C08F220/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F4/00—Polymerisation catalysts
  • C08F4/04—Azo-compounds

Definitions

• a process for the preparation of a polymer composition relates to a process for the preparation of a polymer composition comprising at least one polymer and at least one polyether compound (PE).
• the polymer is obtained by radical polymerization of a monomer composition (M) comprising at least one olefinically unsaturated acid monomer and optionally further monomers such as a chain transfer agent.
• M monomer composition
• the radical polymerization is carried out in at least one continuously operated back-mixed reactor and in the presence of the polyether compound (PE).
• compositions comprising polymers such as polyacids and polyethers is known in the literature:
• WO 2014/090743 A1 describes a process for the continuous preparation of copolymers via radical polymerization of an olefinically unsaturated acid compound and an olefinically unsaturated polyether macromonomer in the presence of a free- radical initiator.
• the reaction is carried out in a polymerization apparatus comprising a loop reactor with an internal mixer and heat exchanger, which has a heat removal power of at least 10 kW/m 3 K.
• a further reactor type is disclosed in the process of WO 2009/133186 A1, in which a monomer, a chain transfer agent and an initiator are pre-mixed and then radically polymerized in a microstructured reactor.
• the smallest dimension at right angles to the flow direction of the mixer and the reaction zone of the reactor are in the region of 1 ⁇ m to 30 mm, which enables a heat removal power of at least 12.5 kW/m 3 K.
• a process for the preparation of a polymer composition comprising at least one polymer and at least one polyether compound (PE), wherein the polymer is obtained by radical polymerization of a monomer composition (M) which comprises the following monomer components a) and b): a) at least one olefinically unsaturated acid monomer (monomer component a)), b) optionally at least one chain transfer agent (monomer component b)),
• C 1 -C 30 -alkyl as defined, for example, below for the R 2 radical in formula (I), mean that this substituent (radical) is an alkyl radical having a carbon atom number from 1 to 30.
• the alkyl radical may be either linear or branched and optionally cyclic.
• Alkyl radicals which have both a cyclic and a linear component are likewise covered by this definition.
• alkyl radicals for example a C 1 -C 4 -alkyl radical or a C 16 -C 22 -alkyl radical.
• alkyl radicals may optionally also be mono- or polysubstituted by functional groups such as amino, quaternary ammonium, hydroxyl, halogen, aryl or heteroaryl. Unless stated otherwise, the alkyl radicals preferably do not have any functional groups as substituents. Examples of alkyl radicals are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 2-ethylhexyl, tert-butyl (tert-Bu/t-Bu), cyclohexyl, octyl, stearyl or behenyl.
• the polymer compositions obtained in the inventive process comprise at least one polymer and at least one polyether compound (PE) and are prepared by radical polymerization of the monomer composition (M) in the presence of the at least one polyether compound (PE).
• the polymer compositions obtained according to the inventive process quite generally comprise the process products of radical polymerization, which are understood to mean, for example, homo- and copolymers of the monomers present in the monomer mixture (M).
• the components present in the monomer composition (M), the at least one polyether compound (PE) and any further optional components that are described below, as well as the amounts of these components all refer to the respective components and amounts before carrying out the radical polymerization.
• the monomer composition (M) comprises at least one olefinically unsaturated acid monomers as monomer component a).
• Suitable olefinically unsaturated acid monomers as monomer component a) are known to the person skilled in the art. in principle, it is possible to use any of the olefinically unsaturated acid monomers that are known to the person skilled in the art and/or that can be produced by known methods.
• olefinically unsaturated acid monomers are compounds having at least one acid functional group such as a carboxylic acid group, a sulfonic acid group or a phosphonic acid group and which additionally comprise at least one hydrocarbon moiety having at least one carbon-carbon double bond.
• the at least one olefinically unsaturated acid monomer a) is selected from ⁇ , ⁇ -ethylenically unsaturated carboxylic acid monomers, ⁇ , ⁇ -ethylenically unsaturated sulfonic acid monomers or ⁇ , ⁇ -ethylenically unsaturated phosphonic acid monomers.
• the at least one olefinically unsaturated acid monomer a) consists of at least one ⁇ , ⁇ -ethylenically unsaturated carboxylic acid monomer.
• ⁇ , ⁇ -ethylenically unsaturated refers to a specific distance of a carbon- carbon double bond of a hydrocarbon moiety relative to the carbon atom of an acid functional group.
• an ⁇ , ⁇ -ethylenically unsaturated acid monomer the carbon atom adjacent to the acid functional group and the next carbon atom of the hydrocarbon moiety are connected by a carbon-carbon double bond. Examples of ⁇ , ⁇ -ethylenically unsaturated acid monomers are described below.
• At least one olefinically unsaturated acid monomer also includes the salts of the aforementioned acids, especially the sodium, potassium and ammonium salts, and also the salts with amines.
• the at least one olefinically unsaturated acid monomer a) can be any one of the aforementioned compounds or a mixture of two or more of the aforementioned compounds.
• the monomer component a) is used in acid form (non-neutralized form) for polymerization.
• acid form non-neutralized form
• the monomer composition (M) comprises at least 40% by weight, preferably at least 60% by weight, especially at least 90% by weight, based on the total weight of the monomer composition (M), of acrylic acid or methacrylic acid.
• the monomer composition (M) comprises at least 40% by weight, preferably at least 60% by weight, especially at least 90% by weight, based on the total weight of the monomer composition (M), of a mixture of acrylic acid and methacrylic acid.
• the monomer component a) in the monomer composition (M) preferably comprises acrylic acid in an amount ranging from 10 to 90% by weight, more preferably from 20 to 80% by weight and especially from 30 to 70% by weight and preferably comprises methacrylic acid in an amount ranging from 90 to 10% by weight, more preferably from 80 to 20% by weight and especially from 70 to 30% by weight, all based on the total weight of the monomer component a) in the monomer composition (M).
• the monomer component a) comprises 50% by weight of acrylic acid and 50% by weight of methacrylic acid, based on the total weight of the monomer component a) in the monomer composition (M).
• the monomer composition (M) comprises at least 40% by weight, preferably at least 60% by weight, especially least 90% by weight, based on the total weight of the monomer composition (M), of acrylic acid.
• the monomer component a) comprises at least one olefinically unsaturated acid monomer component selected from ⁇ , ⁇ -ethylenically unsaturated sulfonic acid monomers or ⁇ , ⁇ -ethylenically unsaturated phosphonic acid monomers
• the monomer composition (M) preferably comprises an amount of 0.1 to 40% by weight, more preferably 1% to 25% by weight, based on the total weight of the monomer composition (M), of said olefinically unsaturated acid monomer.
• Suitable chain transfer agents b) are, for example, aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde or isobutyraldehyde.
• the chain transfer agents b) used may also be formic acid, the salts or esters thereof such as ammonium formate, 2,5-diphenyl-1-hexene, hydroxylammonium sulfate or hydroxylammonium phosphate.
• Compounds which are suitable as chain transfer agents b) and can also serve as solvents are mono- and polyfunctional alcohols.
• they may be selected individually or in a combination from ethyl alcohol, methyl alcohol, propyl alcohol, Isopropanol, butyl alcohol, isobutanol, tert-butyl alcohol, pentyl alcohol, higher alcohols of C12 to C14, methoxyethanol, ethoxyethanol, propoxyethanol, ethylene glycol monoacetate, cyclohexanol, benzyl alcohol, phenethyl alcohol and the like, and from alkylene glycols, for example ethylene glycol, 1 ,2-propanediol, 1,3-propanediol, 1,2- butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3- pentanedi
• the alcohol preferably has a low molecular weight.
• the molecular weight is 400 g/mol or less and more preferably 200 g/mol or less.
• Compounds of this type are, for example, inorganic hydrogensulfites, disulfites and dithionites, or organic sulfides, disulfides, polysulfides, sulfoxides and sulfones. These include di-n-butyl sulfide, di-n-octyl sulfide, diphenyl sulfide, thiodiglycol, ethylthioethanol, diisopropyl disulfide, di-n-butyl disulfide, di-n-hexyl disulfide, diacetyl disulfide, diethanol sulfide, di-tert-butyl trisulfide, dimethyl sulfoxide, dialkyl sulfide, dialkyl disulfide or diaryl sulfide.
• Suitable chain transfer agents b) are also mercaptans (compounds which comprise sulfur in the form of SH groups, also known as thiols).
• Preferred chain transfer agents b) are mono-, bi- and polyfunctional mercaptans, mercaptoalcohols and/or mercapto- carboxylic acids.
• the at least one chain transfer agent b) is simultaneously used as the solvent, alcohols and alkyl halides are used as chain transfer agents.
• the at least one chain transfer agent b) is selected from aldehydes, formic acid, alkyl halides, mono- and polyfunctional alcohols, hydroxycarboxylic acids, ally) compounds, mercaptans, hypophosphorus acid or the salts of hypophosphorus acid. More preferably the chain transfer agent b) is selected from formic acid, mercaptans or sodium hypophosphite.
• the chain transfer agent b) can be used as such or dissolved in a solvent. In general, the chain transfer agent b) is used dissolved in a suitable solvent. If present in the monomer composition (M), chain transfer agent b) is used preferably in an amount of from 0.05 to 25% by weight and more preferably from 0.1 to 10% by weight, based on the total weight of the monomer composition (M).
• the amount of the chain transfer agent b) in the monomer composition (M) has a strong influence on the mean molecular weight of the polymer composition. When less chain transfer agent b) is used, this usually leads to higher mean molecular weights of the polymer formed. If, in contrast, greater amounts of chain transfer agent b) are used, this usually leads to a lower mean molecular weight.
• the monomer composition (M) may optionally comprise at least one further monomer other than monomer components a) and b). It will be acknowledged by those skilled in the art that the at least one further monomer is different from monomer components a) and b).
• the monomer composition (M) additionally comprises at least one further monomer selected from d) polyether acrylates, allyl alcohol alkoxylates e) vinylaromatics, f) esters of ⁇ , ⁇ -ethylenically unsaturated mono- and dicarboxylic acids with C 1 -C 20 - alkanols, g) compounds having one free-radically polymerizable ⁇ , ⁇ -ethylenically unsaturated double bond and at least one cationogenic and/or cationic group per molecule, h) esters of vinyl alcohol or allyl alcohol with C 1 -C 30 -monocarboxylic acids, i) olefinically unsaturated monomers containing amide groups, k) esters of ⁇ , ⁇ -ethylenically unsaturated mono- and dicarboxylic acids with C 2 -C 30 - alkanediols, amides of ⁇ , ⁇ -ethylenically unsaturated
• the at least one further monomer preferably is at least one monomer selected from polyether acrylates, allyl alcohol alkoxylates, vinylaromatics, esters of ⁇ , ⁇ -ethylenically unsaturated mono- and dicarboxylic acids with C 1 -C 20 -alcanols, compounds having one free-radically polymerizable ⁇ , ⁇ -ethyienically unsaturated double bond and at least one cationogenic group per molecule, compounds having one free-radically polymerizable double bond and at least one cationic group per molecule, compounds having one free-radically polymerizable ⁇ , ⁇ -ethylenically unsaturated double bond and at least one cationogenic and at least one cationic group per molecule, esters of vinyl alcohol or ally!
• the monomer composition (M) may preferably comprise the at least one further monomer in an amount of 0% to 30% by weight, more preferably 0% to 20% by weight, especially 0% to 10% by weight, based on the total weight of the monomer composition (M).
• the monomer composition (M) comprises at least one further monomer component, then preferably in an amount of 0.1% to 30% by weight, more preferably 1% to 20% by weight, especially 1.5% to 10% by weight, based on the total weight of the monomer composition (M).
• the proportions by weight of all monomer components present in the monomer composition (M) generally add up to 100%.
• the monomer composition (M) does not comprise any further monomers.
• Suitable polyether acrylates and allyl alcohol alkoxylates as monomer component d) are selected from compounds of the general formulae (I) and (II):
• k and I are each independently an integer from 0 to 1000, where the sum of k and I is at least 2, preferably at least 5, R 1 is hydrogen or C 1 -C 8 -alkyl, R 2 is hydrogen, C 1 -C 30 -alkyl, CrCao-alkenyl or C 5 -C 8 -cycloalkyl, X is O or a group of the formula NR 3 in which R 3 is H, alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl.
• k is preferably an integer from 1 to 500, more preferably 2 to 400, especially 3 to 250.
• I is an integer from 0 to 100.
• R 1 in the formula (I) is hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl or n-hexyl, especially hydrogen, methyl or ethyl.
• R 2 in the formulae (I) and (II) is hydrogen, n-octyi, 1,1,3,3-tetramethylbutyl, ethylhexyl, n-nonyl, n-decyl, n-undecyl, tridecyl, myristyl, pentadecyl, palmityl, heptadecyl, octadecyl, nonadecyl, arachinyl, behenyl, lignoceryl, cerotinyl, melissyl, palmitoleyl, oleyl, linoleyl, linolenyl, stearyl, lauryl.
• X in the formula (I) is O or NH, especially O.
• Suitable polyether acrylates according to formula (I) are, for example, the polycondensation products of the aforementioned ⁇ , ⁇ -ethylenically unsaturated mono- and/or dicarboxylic acids and the acid chlorides, acid amides and acid anhydrides thereof with polyetherols.
• Suitable polyetherols can be prepared easily by reacting ethylene oxide, propylene 1,2-oxide and/or epichlorohydrin with a starter molecule such as water or a short-chain alcohol R 2 -OH.
• the alkylene oxides can be used individually, alternately in succession, or as a mixture.
• the polyether acrylates l.a) can be used alone or in mixtures to prepare the polymers used in accordance with the invention.
• Suitable allyl alcohol alkoxylates according to formula (II) are, for example, the etherification products of allyl chloride with appropriate polyetherols.
• Suitable polyetherols can be prepared easily by reacting ethylene oxide, propylene-1 ,2-oxide and/or epichlorohydrin with a starter alcohol R 2 -OH.
• the alkylene oxides can be used individually, alternately in succession, or as a mixture.
• the allyl alcohol alkoxylates (II) can be used alone or in mixtures to prepare the polymers used in accordance with the invention.
• Monomer components d) used are especially methyl diglycol acrylate, methyl diglycol methacrylate, ethyl diglycol acrylate or ethyl diglycol methacrylate. Preference is given to ethyl diglycol acrylate.
• Preferred monomer components e) are styrene, 2-methylstyrene, 4-methylstyrene, 2-(n-butyl)styrene, 4-(n-butyl)styrene or 4-(n-decyl)styrene. Particular preference is given to styrene or 2-methylstyrene, especially styrene.
• Suitable monomer components f) are, for example, methyl (meth)acrylate, methyl ethacrylate, ethyl (meth)acrylate, ethyl ethacrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, tert-butyl ethacrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 1 ,1,3,3-tetramethylbutyl (meth)acrylate, ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-undecyl (meth)acrylate
• the cationogenic and/or cationic groups of monomer component g) are preferably nitrogen-containing groups such as primary, secondary or tertiary amino groups, or quaternary ammonium groups.
• the nitrogen-containing groups are tertiary amino groups or quaternary ammonium groups.
• Charged cationic groups can be produced from the amine nitrogens either by protonation or by quaternization with acids or alkylating agents.
• Examples of these include carboxylic acids such as lactic acid, or mineral acids such as phosphoric acid, sulfuric acid or hydrochloric acid, and examples of alkylating agents include C 1 -C 4 -alkyl halides or sulfates, such as ethyl chloride, ethyl bromide, methyl chloride, methyl bromide, dimethyl sulfate or diethyl sulfate.
• a protonation or quaternization may usually either precede or follow the polymerization.
• monomer component g) is selected from esters of ⁇ , ⁇ -ethylenically unsaturated mono- or dicarboxylic acids with amino alcohols which may be mono- or dialkylated on the amine nitrogen, amides of ⁇ , ⁇ -ethylenically unsaturated mono- or dicarboxylic acids with diamines having at least one primary or secondary amino group, ⁇ , ⁇ -diallylamine, N,N-diallyl-N-alkylamines and derivatives thereof, vinyl- or allyl- substituted nitrogen heterocycles or vinyl- or allyl-substituted heteroaromatic compounds.
• Preferred monomer components g) are N-methylaminoethyl (meth)acrylate, N-ethylaminoethyl (meth)acrylate, N-(n-propyl)aminoethyl (meth)acrylate, N-(tert- N.N-dimethylaminomethyl (meth)acrylate, ⁇ , ⁇ -dimethylaminoethyl (meth)acrylate, ⁇ , ⁇ -diethylaminomethyl (meth)acrylate, ⁇ , ⁇ -diethylaminoethyl (meth)acrylate, ⁇ , ⁇ -dimethylaminopropyl (meth)acrylate, ⁇ , ⁇ -diethylaminopropyl (meth)acrylate or ⁇ , ⁇ -dimethylaminocyclohexyl (meth)acrylate.
• Suitable monomer components g) are additionally the amides of the aforementioned ⁇ , ⁇ -ethylenically unsaturated mono- and dicarboxylic acids with diamines having at least one primary or secondary amino group. Preference is given to diamines having one tertiary amino group and one primary or secondary amino group.
• Examples of preferred monomer components g) are N-[tert- butylaminoethyl](meth)acrylamide, N-[2-(dimethyfamino)ethyl]acrylamide, N-[2- (dimethylamino)ethyl]methacrylamide, N-[3-(dimethylamino)propyl]acrylamide, N-[3- (dimethylamino)propyl]methacrylamide, N-[4-(dimethylamino)butyl]acrylamide, N-[4 ⁇ (dimethylamino)butyl]methacrylamide, N-[2-(diethylamino)ethyl]acrylamide, N-[4- (dimethylamino)cyclohexyl]acrylamide or N-[4-(dimethylamino)cyclohexyl]meth- acrylamide.
• monomer component g) comprises, as vinyl-substituted heteroaromatic compound, at least one N-vinylimidazole compound or at least one N-vinyl pyridine compound.
• monomer component g) is selected from N-vinylimidazole compounds, N-vinyl pyridine compounds and mixtures comprising at least one N-vinylimidazole compound or at least one N-vinyl pyridine compound.
• Suitable N-vinylimidazole compounds are compounds of the formula (III):
• R 3 to R 5 are each independently hydrogen, C 1 -C 4 -alkyl or phenyl.
• R 1 to R 3 are hydrogen.
• Ph phenyl
• Preferred monomer components g) are 1-vinylimidazole (N-vinylimidazole) and mixtures comprising N-vinylimidazole.
• Suitable monomer components g) are also the compounds obtainable by protonating or quaternizing the aforementioned N-vinylimidazole compounds. Examples of such charged monomer components g) are quaternized vinylimidazoles, in particular 3-methyl-1-vinylimidazolium chloride, 3-methyM-vinylimidazolium methylsulfate or
• Suitable monomer components g) are additionally vinyl- and allyl-substituted nitrogen heterocycles other than vinylimidazoles, such as 2- or 4-vinylpyridine, 2- or
• Suitable monomer components h) are, for example, methyl vinyl ester, ethyl vinyl ester, n-propyl vinyl ester, isopropyl vinyl ester, n-butyl vinyl ester, tert-butyl vinyl ester, n-pentyl vinyl ester, n-hexyl vinyl ester, n-heptyl vinyl ester, n-octyl vinyl ester, 1,1,3,3- tetramethylbutyl vinyl ester, ethylhexyl vinyl ester, n-nonyl vinyl ester, n-decyl vinyl ester, n-undecyl vinyl ester, tridecyl vinyl ester, myristyl vinyl ester, pentadecyl vinyl ester, palmityl vinyl ester, heptadecyl vinyl ester, octadecyl vinyl ester, nonadec
• the compounds of monomer component i) are selected from primary amides of ⁇ , ⁇ -ethylenically unsaturated monocarboxylic acids, N-vinylamides of saturated monocarboxylic acids, N-vinyllactams, N-alkyl- or ⁇ , ⁇ -dialkylamides of ⁇ , ⁇ - ethylenically unsaturated monocarboxylic acids.
• Preferred monomer components i) are N-vinyllactams and derivatives thereof which may have, for example, one or more Cj-Ce-alkyl substituents such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-birtyl, etc.
• N-vinylpyrrolidone N-vinylpiperidone, N-vinylcaprolactam
• N-vinyl-5-methyl-2- pyrrolidone N-vinyl-5-ethyl-2-pyrrolidone
• N-vinyl-6-methyl-2-piperidone N-vinyl-6- ethyl-2-piperidone
• N-vinyl-7-methyl-2-caprolactam N-vinyl-7-ethyl-2-caprolactam, etc.
• Suitable monomer components i) are additionally acrylamide or methacrylamide.
• Suitable N-alkyl- and ⁇ , ⁇ -dialkylamides of ⁇ , ⁇ -ethylenically unsaturated monocarboxylic acids are, for example, methyl(meth)acrylamide, methylethacrylamide, ethyl(meth)acrylamide, ethylethacrylamide, n-propyl(meth)acrylamide, isopropyl- (meth)acrylamide, n-butyl(meth)acrylamide, tert-butyl(meth)acrylamide, tert-butyl- ethacrylamide, n-pentyl(meth)acrylamide, n-hexyl(meth)acrylamide, n-heptyl- (meth)acrylamide, n-octyl(meth)acrylamide, 1 ,1 ,3,3-tetramethylbutyl(meth)acrylamide, ethylhexyl(meth)acrylamide, n-nonyl(
• Open-chain N-vinylamide compounds suitable as monomer components i) are, for example, N-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N- methylacetamide, N-vinyl-N-ethylacetamide, N-vinylpropionamide, N-vinyl-N-methyl- propionamide or N-vinylbutyramide. Preference is given to using N-vinylformamide.
• Suitable monomer components I) are acrylonitrile or methacrylonitrile.
• Suitable monomer components m) are N-vinylurea, N-allylurea or derivatives of imidazolidin-2-one. These comprise N-vinyl- and N-allylimidazolidin-2-one, N- vinyloxyethylimidazolidin-2-one, N-(2-(meth)acrylamidoethyl)imidazolidin-2-one, N-(2- (meth)acryloyloxyethyl)imidazolidin-2-one (i.e. 2-ureido(meth)acrylate), N-[2- ((meth)acryloyloxyacetamido)ethyl]imidazolidin-2-one, etc.
• the monomer composition (M) comprises
• the monomer composition (M) comprises 75 to 92% by weight of the at least one olefinically unsaturated acid monomer a), and
• Radical polymerization processes as such and processes for preparing a polymer composition are known to those skilled in the art (see also below).
• the radical polymerization can be carried out optionally in the presence of at least one free-radical initiator (P).
• Free-radical initiators in the context of the invention are compounds that can produce radical species usually under mild conditions and promote radical reactions. These substances usually possess at least one group with weak atom— atom bonds that has small bond dissociation energies and can be cleaved thermolytically or photolytically. Suitable free-radical initiators are known to those skilled in the art. In principle, it is possible to use any of the free-radical initiators that are known to the person skilled in the art and/or that can be produced by known methods.
• - peroxide compounds include, for example, organic peroxides and hydroperoxides such as acetyl hydroperoxide, diacetyl peroxide, benzoyl hydroperoxide, dibenzoyl peroxide, lauroyl peroxide, dilauroyl peroxide, succinyl peroxide, tert-butyl peroxyisobutyrate, caproyl peroxide, cumyl hydroperoxide, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, tert-amyl hydroperoxide, di-tert-amyl peroxide, tert-butyl peroxyacetate, tert-butyl peroxy-2- ethylhexanoate, tert-butyl peroxymaleate, tert-butyl peroxybenzoate, tert-butyl peroxyoctoate, tert-butyl
• the initiator systems preferably comprise a sulfur compound which is especially selected from sodium hydrogensulfite, sodium hydroxymethanesulfinate and the hydrogensulfite adduct to acetone.
• a sulfur compound which is especially selected from sodium hydrogensulfite, sodium hydroxymethanesulfinate and the hydrogensulfite adduct to acetone.
• suitable reducing agents are nitrogen and phosphorus compounds such as phosphorous acid, hypophosphites and phosphinates, di-tert-butyl hyponitrite and dicumyl hyponitrite, and also hydrazine and hydrazine hydrate and ascorbic acid.
• redox initiator systems may comprise an addition of small amounts of redox metal salts such as iron salts, vanadium salts, copper salts, chromium salts or manganese salts; suitable redox initiator systems are, for example, the ascorbic acid/iron(ll) sulf ate/sodium peroxodisulfate redox initiator system, tert-butyl hydroperoxide/sodium disulfite, tert-butyl hydroperoxide/sodium hydroxymethane sulfinate and hydrogen peroxide/Cu'.
• redox metal salts such as iron salts, vanadium salts, copper salts, chromium salts or manganese salts
• suitable redox initiator systems are, for example, the ascorbic acid/iron(ll) sulf ate/sodium peroxodisulfate redox initiator system, tert-butyl hydroperoxide/sodium disulfite
• the amount of the at least one free-radical initiator (P) used typically ranges from 0.1 to 20% by weight, in particular from 0.2 to 10% by weight and especially from 0.5 to 7% by weight, based on the total amount of monomers to be polymerized.
• the at least one free-radical initiator (P) can be used as such or dissolved in a solvent. Preference is given to using the at least one free-radical initiator (P) dissolved in a suitable solvent. Suitable solvents are those specified for the polymerization below.
• the radical polymerization is carried out in the presence of at least one polyether compound (PE).
• PE polyether compound
• Suitable polyether compounds are generally known to those skilled in the art.
• the proportion of repeat alkylene oxide units is at least 30% by weight, based on the total weight of the compound.
• Suitable polyetherols are polyalkylene glycols, such as polyethylene glycols, polypropylene glycols, polytetrahydrofurans and alkylene oxide copolymers.
• Suitable alkylene oxides for preparation of alkylene oxide copolymers are, for example, ethylene oxide, propylene oxide, epichlorohydrin, 1,2- butylene oxide and 2,3-butylene oxide. Suitable examples are copolymers of ethylene oxide and propylene oxide, copolymers of ethylene oxide and butylene oxide, and copolymers of ethylene oxide, propylene oxide and at least one butylene oxide.
• The may comprise the copolymerized alkylene oxide units in random distribution or in the form of blocks.
• the proportion of repeat units derived from ethylene oxide in the ethylene oxide/propylene oxide copolymers is 40% to 99% by weight.
• Particularly preferred polyether compounds (PE) are ethylene oxide homopolymers and ethylene oxide/propylene oxide copolymers.
• Suitable polyether compounds (PE) are additionally the mono- and di-(C 1 -C 2 -alkyl) ethers of the above-described polyetherols. Preference is given to polyalkylene glycol monomethyl ethers and polyalkylene glycol dimethyl ethers.
• Suitable polyether compounds (PE) are additionally surfactants containing polyether groups. In general, non-ionic and ionic surfactants having at least one non-polar group and at least one polar group and comprising a polyether group are suitable.
• the surfactants containing polyether groups are preferably selected from alkyl polyoxyalkylene ethers, aryl polyoxyalkylene ethers, alkylaryl polyoxyalkylene ethers, alkoxylated animal, alkoxylated animal oils, alkoxylated vegetable fats, alkoxyiated vegetable oils, fatty amine alkoxylates, fatty acid amide alkoxylates, fatty acid diethanolamide alkoxylates, polyoxyethylene sorbitan fatty acid esters, alkyl polyether sulfates, aryl polyether sulfates, alkylaryl polyether sulfates, alkyl polyether sulfonates, aryl polyether sulfonates, alkylaryl polyether sulfonates, alkyl polyether phosphates, aryl polyether phosphates, alkylaryl polyether phosphates, glyceryl ether sulfonates, glyceryl ether s
• R 10 is a linear or branched alkyl radical having 6 to 22 carbon atoms
• R 11 and R 12 are each independently hydrogen or a linear or branched alkyl radical having 1 to 10 carbon atoms or H, where R 12 is preferably methyl
• x and y are each independently 0 to 300.
• fatty alcohol alkoxylates and oxo alcohol alkoxylates such as isotridecyl alcohol polyoxyethylene ethers and oleyl alcohol polyoxyethylene ethers.
• surfactants containing hydroxyl groups of the general formula (VII)' where the sequence of the alkylene oxide units in the compounds of the formula (VII) is arbitrary, s, t, u and v are each independently an integer from 0 to 500, where the sum of s, t, u and v is > 0,
• R 13 and R 15 are each independently a straight-chain or branched saturated C 1 -C 40 - alkyl radical or a mono- or polyunsaturated C 2 -C 40 -alkenyl radical, and
• R u is selected from methyl, ethyl, n-propyl, isopropyl and n-butyl.
• the sum of s, t, u and v is preferably a value of 10 to 300, more preferably of 15 to 200 and especially of 20 to 150.
• t and u are each 0.
• the sum of s and v is preferably a value of 10 to 300, more preferably of 15 to 200 and especially of 20 to 150.
• R 13 and R 15 are each independently a straight-chain or branched saturated C 2 -C 30 -alkyl radical. At the same time, R 13 and R 15 may also be mixtures of different alkyl radicals.
• R 14 is preferably methyl or ethyl, especially methyl.
• a preferred embodiment comprises surfactants containing hydroxyl groups of the general formula (VII .1 ) where the sequence of the -(CH 2 CH 2 O)- and the -(CH 2 CH(CH 3 )O)- units is arbitrary, s and v are each independently an integer from 0 to 500, where the sum of s and v is > 0,
• R 13 and R 15 are each independently a straight-chain saturated C 1 -C 30 -alkyl radical or a branched saturated C 3 -C 30 -alkyl radical or a mono- or polyunsaturated
• the sum of s and v is preferably a value of 10 to 300, more preferably of 15 to 200 and especially of 20 to 150.
• sequence of the alkylene oxide units in the compounds of the formula (VIII) is arbitrary, p and q are each independently an integer from 0 to 500, where the sum of p and q is > 0,
• R 16 and R 18 are each independently a straight-chain or branched saturated C 1 -C 40- alkyl radical or a mono- or polyunsaturated C 2 -C 40 -alkenyl radical, and R 17 is selected from methyl, ethyl, n-propyl, isopropyl and n-butyl.
• the sum of p and q is preferably a value of 10 to 300, more preferably of 15 to 200 and especially of 20 to 150.
• R 18 and R 18 are each independently a straight-chain or branched saturated C 4 -C 3 (ralkyl radical. At the same time, R 16 and R 18 different alkyl radicals.
• R 17 is preferably methyl or ethyl, especially methyl. These include, for example, lauryl alcohol polyoxyethylene acetate.
• alkylaryl alcohol polyoxyethylene ethers for example octylphenol polyoxyethylene ethers, - alkoxylated animal fats, alkoxylated animal oils, alkoxylated vegetable fats, alkoxylated vegetable oils, for example corn oil ethoxylates, castor oil ethoxylates, tallow fat ethoxylates, alkylphenol alkoxylates, for example ethoxylated isooctyl-, octyl- or nonylphenol, tributylphenol polyoxyethylene ether, fatty amine alkoxylates, fatty acid amide and fatty acid diethanolamide alkoxylates, especially ethoxylates thereof, - polyoxyalkylene sorbitan fatty acid esters.
• octylphenol polyoxyethylene ethers for example octylphenol polyoxyethylene ethers, - alkoxylated animal fats, alkoxylated animal oils, alkoxy
• alkyl polyether sulfate sodium dodecyl poly(oxyethylene) sulfate (sodium lauryl ether sulfate, SLES).
• the weight ratio of the monomer mixture (M) to the at least one polyether compound (PE) is preferably in the range from 1:10 to 10:1, more preferably in the range from 1:8 to 8:1 and especially in the range from 1 :5 to 5:1.
• the at least one polyether compound (PE) generally does not have any copolymerizable double bond and affords specific polymer compositions having advantageous properties. Without being bound to a theory, this may be attributable, for example, to hydrogen bonding between the at least one polymer on the one hand and the at least one polyether compound (PE) on the other hand, leading to polymer- polyether complex formation in the polymer composition.
• the monomer composition (M) and the at least one polyether compound (PE) do not comprise any olefinically unsaturated polyether macromonomers, such as those defined in WO 2014/090743.
• the radical polymerization can be carried out in the presence of at least one solvent (S) selected from water, CVCe-alkanols, polyols other than the at least one polyether compound (PE), the mono- and dialkyl ethers thereof, aprotic polar solvents and mixtures thereof.
• S solvents
• Suitable solvents (S) are known to the person skilled in the art.
• Suitable aprotic polar solvents are pyrrolidones and pyrrolidone derivatives. These especially include 2-pyrrolidone (y-butyrolactam) and N-methylpyrrolidone.
• Suitable polyols and the mono- and dialkyl ethers thereof also comprise alkylene glycol mono-(C 1 -C 4 -alkyl) ethers, alkylene glycol di-(C 1 -C 4 -alkyl) ethers, oligoalkylene glycols having a number-average molecular weight of less than 200 g/mol and the mono- (C 1 -C 4 -alkyl) ethers and di-(C 1 -C 4 -alkyl) ethers thereof.
• the at least one solvent (S) is preferably selected from water, methanol, ethanol, n-propanol, isopropanol, n-butanol, ethylene glycol, ethylene glycol mono-(C 1 -C 4 -alkyl) ethers, ethylene di-(C 1 -C 4 -alkyl) glycol ethers, 1,2-propylene glycol, 1,2-propylene glycol mono-(C 1 -C 4 -alkyl) ethers, 1 ,2-propylene glycol di-(C 1 -C 4 -alkyl) ethers, glycerol, polyglycerols, 2-pyrrolidone, N-methylpyrrolidone, oligoalkylene glycols having a number-average molecular weight of less than 200 g/mol and mixtures thereof.
• Suitable oligoethylene glycols are commercially available under the CTFA designations PEG-6, PEG-8, PEG-12, PEG-6-32, PEG-20, PEG-150, PEG-7M, PEG-12M and PEG- 115M. These especially include the Pluriol E ® products from BASF SE. Suitable alkyl polyalkylene glycols are the corresponding Pluriol A ... E ® products from BASF SE. Preference is given to the isomeric dipropylene glycols such as 1,1'-oxydi-2-propanol, 2,2'-oxydi-1-propanol, 2-(2-hydroxypropoxy)-1-propanol and mixtures thereof.
• the at least one solvent (S) is more preferably selected from water, ethanol, n-propanol, isopropanol, ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,2- dipropylene glycol, glycerol, oligoglycerol, polyglycerol and mixtures thereof.
• the at least one solvent (S) used is selected from water and a mixture of water and at least one further solvent other than water, selected from ethanol, n-propanol, isopropanol, ethylene glycol, diethylene glycol, 1 ,2-propylene glycol, 1 ,2-dipropylene glycol, glycerol, oligoglycerol, polyglycerol and mixtures thereof.
• the reaction mixture comprising the at least one olefinically unsaturated acid monomer a), optionally the at least one chain transfer agent b), the at least one polyether compound (PE), optionally the at least one free-radical initiator (P), the at least one solvent (S) and optionally the at least one further monomer comprises at least 10% by weight, preferably at least 15% by weight, especially at least 20% by weight, based on the total weight of said reaction mixture, of the at least one solvent (S).
• the reaction mixture comprising the at least one olefinically unsaturated acid monomer a), optionally the at least one chain transfer agent b), the at least one polyether compound (PE), optionally the at least one free-radical initiator (P), the at least one solvent (S) and optionally the at least one further monomer comprises at least 10% by weight, preferably at least 15% by weight, especially at least 20% by weight, based on the total weight of said reaction mixture, of the at least one solvent (S).
• the reaction mixture comprising the at least one olefinically unsaturated acid monomer a), optionally the at least one chain transfer agent b), the at least one polyether compound (PE), optionally the at least one free-radical initiator (P), the at least one solvent (S) and optionally the at least one further monomercomprises 10% to 90% by weight, preferably 15% to 80% by weight, especially 20% to 70% by weight, based on the total weight of said reaction mixture, of the at least one solvent (S).
• the reaction mixture comprising the at least one olefinically unsaturated acid monomer a), optionally the at least one chain transfer agent b), the at least one polyether compound (PE), optionally the at least one free-radical initiator (P), the at least one solvent (S) and optionally the at least one further monomercomprises 10% to 90% by weight, preferably 15% to 80% by weight, especially 20% to 70% by weight, based on the total weight of said reaction mixture, of the at least one solvent (S).
• the weight ratio of the at least one polyether compound (PE) to the at least one solvent (S) is preferably in the range from 0.3:1 to 5:1, more preferably in the range from 0.5:1 to 3:1.
• the radical polymerization can be carried out at any temperature.
• the radical polymerization is carried out at a temperature in the range from 20 to 150°C, more preferably from 30 to 120°C, especially from 50 to 90°C.
• the radical polymerization can be carried out at ambient pressure or reduced or elevated pressure. Preferably, the radical polymerization is carried out at ambient pressure.
• the polymerization is usually carried out at constant temperature, but can also be varied during the radical polymerization if required.
• the polymerization temperature is kept very substantially constant within the at least one continuously operated back-mixed reactor.
• the polymerization temperature varies typically within the range from 20 to 150°C.
• the polymerization temperature varies within the range from 30 to 120°C and especially within the range from 50 to 90°C. If the polymerization is not conducted under elevated pressure and at least one optional solvent (S) has been added to the reaction mixture, the at least one solvent (S) determines the maximum reaction temperature via the corresponding boiling temperatures.
• the polymer composition obtained in the inventive process preferably comprises more than 1 mmol/g, more preferably more than 1.3 mmol/g of acid groups.
• the polymer composition obtained in the inventive process preferably comprises less than 15 mmol g of acid groups.
• the polymer composition obtained in the inventive process especially comprises 1.5 mmol/g to 15 mmol g of acid groups.
• the acid groups of the polymer composition obtained in the inventive process are in non-neutralized form.
• the weight average molecular weight M w of the polymer composition obtained in the inventive process is usually in the range from 1 000 to 150 000 g/mol.
• the weight average molecular weights M w are measured using gel permeation chromatography (GPC). Neutralized polyacrylic acid was used as standard in the measurements.
• the polymer composition preferably comprises less than 50% by weight, preferably less than 30% by weight, especially less than 10% by weight, based on the total weight of said reaction mixture, of the at least one solvent (S).
• the polymer composition preferably comprises at least 0.1% by weight, preferably at least 0.5% by weight, especially at least 1% by weight, based on the total weight of said reaction mixture, of the at least one solvent (S).
• the solids content of the polymer composition is preferably greater than 50% by weight, more preferably greater than 70% by weight and especially preferably greater than 90% by weight, based on the total weight of the said reaction mixture.
• the term "solids content” refers to the total amount of components in the polymer composition, which are usually present as a solid after the radical polymerization.
• the radical polymerization is carried out in at least one continuously operated back-mixed reactor.
• continuously operated or ..continuous operation refer to a process in which all materials that are being processed and produced are usually in steady motion throughout the respective employed reactor as a flowing stream and usually undergo chemical reactions or can be subject to mechanical or heat treatment.
• continuously operated reactors can be operated for an unpredetermined long duration and are usually operated without interruptions, except for infrequent maintenance shutdowns.
• the terms .back-mixed reactor or termed” refer to a special type of reactor in which volume elements are mixed with preceding and following volume elements. This can be achieved, for example by implementing suitable internal mixing elements into the reactor and/or by recycling at least part of the reaction mixture.
• a continuously operated back-mixed reactor is usually completely back-mixed in space and time, and therefore, the temperature and the concentration of components within the reaction mixture remain uniform in each volume element within the reactor.
• any continuously operated reactor which provides back-mixing can be used in the inventive process.
• Continuously operated back-mixed reactors include continuous-flow stirred-tank reactors, loop reactors and slurry reactors, all of which are well known to those skilled in the chemical arts.
• the at least one continuously operated back-mixed reactor used in the inventive process is a loop reactor.
• a "loop reactor” comprises a tubular reactor which enables recycling of the reaction mixture.
• the loop reactor is continuously operated according to the inventive process and preferably has a volume-based heat removal power of at least 10 kW/m 3 , preferably at least 25 kW/m 3 K and especially at least 50 kW/m 3 . This can be achieved, for example, by using tube bundle or plate heat exchangers, among others.
• the loop reactor comprises an apparatus for circulating the reaction medium.
• such devices are gear pumps.
• the loop reactor preferably comprises at least one reaction zone with internal cooling and mixing elements over which the reaction medium flows by convection in the mixing section. This can be achieved, for example, by integration of a tube reactor having cooling and mixing elements into the at least one loop reactor, where the tube reactor can be, for example, a tube reactor of the type CSE-XR from Fluitec Georg AG or an SMR reactor from Sulzer.
• reaction zone is understood to mean a section of a reactor in flow direction of the liquid streams in which the polymerization proceeds.
• a reaction zone may be disposed within part of a reactor, within a whole reactor or within two or more reactors. In a preferred embodiment, each reaction zone is disposed in a separate reactor.
• the internal cooling elements not only enable a very large area for heat exchange between cooling medium and reaction mixture to be generated and a high heat transfer power thus to be achieved, but the cooling elements at the same time ensure and improve mixing of the reaction mixture.
• the simultaneous mixing and heat removal thus makes a high level of heat removal possible at low temperature differences between cooling medium and reaction mixture. This is in turn an important prerequisite for keeping the continuous reaction in a narrow temperature window independently of the exact throughput.
• Loop reactors with internal cooling and mixing elements used in the inventive process are also operated continuously and are suitable for ensuring thermal homogeneity transverse to the flow direction.
• each differential volume element in principle has essentially the same temperature over the particular flow cross section.
• the characteristic dimension of a device for example of a reactor, is understood to mean the smallest to the flow direction.
• the characteristic dimension of the reaction zone of a loop reactor with internal cooling and mixing elements is significantly less than that of a conventional loop reactor (for example at least by a factor of 10 or at least by a factor of 100 or even at least by a factor of 1000) and is typically in the range from several hundreds of nanometers to a few tens of millimeters. It is frequently in the range from 1 ⁇ to 30 mm.
• loop reactors with internal cooling and mixing elements therefore exhibit significantly different behavior in relation to the heat and mass transfer processes which proceed.
• the greater ratio of surface area to reactor volume for example, very good heat supply and removal is enabled, which is why it is also possible to carry out strongly endo- or exothermic reactions virtually isothermally.
• the characteristic dimension of the reaction zone of a conventional loop reactor ranges from 30 mm to 700 mm, preferably from 30 mm to 600 mm, more preferably from 30 mm to 500 and particularly preferably from 30 mm to 400 mm.
• the characteristic dimension of the reaction zone of a loop reactor with internal cooling and mixing elements is at most 30 mm, for example from 0.1 to 30 mm or preferably from 0.2 to 30 mm or more preferably from 0.4 to 30 mm; preferably at most 20 mm, for example from 0.1 to 20 mm or preferably from 0.2 to 20 mm or more preferably from 0.4 to 20 mm; more preferably at most 15 mm, for example from 0.1 to 15 mm or preferably from 0.2 to 15 mm or more preferably from 0.4 to 15 mm; even more preferably at most 10 mm, for example from 0.1 to 10 mm or preferably from 0.2 to 10 mm or more preferably from 0.4 to 10 mm; even more preferably at most 8 mm, for example from 0.1 to 8 mm or preferably from 0.2 to 8 mm or more preferably from 0.4 to 8 mm; in particular at most 6 mm, for example from 0.1 to 6 mm or preferably from 0.2 to 6 mm or more preferably from 0.4 to 30
• the loop reactors with internal cooling and mixing elements may comprise mixing elements permeated by temperature control channels (for example of the CSE- XR type from Fluitec, Switzerland).
• temperature control channels for example of the CSE- XR type from Fluitec, Switzerland.
• Advantageous materials for the mixers and reactors for use in accordance with the invention have been found to be austenitic stainless steels which are corrosion- resistant in the region of low temperatures, such as 1.4541 or 1.4571, generally known as V4A and as V2A respectively, and stainless steels of US types SS316 and SS317Ti.
• PEEK polyetheretherketone
• thermoplastic material is likewise suitable.
• the heat transfer is selected such that temperature deviations in the reaction medium relative to the temperature of the temperature control medium of less than 40 °C, preferably of less than 20 °C, more preferably of less than 10 °C and especially of less than 5 °C occur.
• the reaction can thus proceed under substantially isothermal and hence defined and controlled conditions.
• the inventive process is preferably carried out continuously.
• starting materials such as monomers (possibly together with further materials such as solvents, gases, etc.) are usually fed simultaneously to the reaction zone/reactor at a constant rate and at preset ratios and a constant rate of a product stream is taken from the reaction zone/reactor.
• a general description of continuous processes and alternative definitions may be found in textbooks on chemical process engineering (e.g. E. Fitzner, W. Fritz, E. Klemm Technische Chemie: Einfiihrung in die chemische endeavorstechnik", 2005, 5th edition, Springer, Berlin-ISBN 3540234527).
• the at least one olefinically unsaturated acid monomer a), the at least one polyether compound (PE), optionally the at least one chain transfer agent b) and optionally the free-radical initiator (P) are fed into the at least one continuously operated back-mixed reactor each via different feed lines.
• the above-described compounds are usually fed into the reactor in liquid form.
• Monomers liquid under the feeding conditions can be fed into the at least one continuously operated back-mixed reactor without addition of a solvent (S); otherwise, the compounds are used as a solution in a suitable solvent (S).
• the feeding rates for the at least one olefinically unsaturated acid monomer a) and of any further feeds (initiator (P), chain transfer agent b), etc.) are preferably chosen such that the polymerization is maintained with the desired conversion rate.
• the individual feeds can be added continuously, periodically, with constant or varying metering rate, and essentially simultaneously or offset in time. Preferably, all feeds are added to the reaction mixture continuously.
• Suitable mixers are known from the prior art. They may in principle be mixers with or without microstructures. Suitable mixers without microstructures, which are also referred to as "conventional" mixers in the context of the present invention, are all mixers which are suitable for the continuous mixing of liquids and are sufficiently well- known to those skilled in the art. They are selected according to the process technology requirements.
• the characteristic dimension of a flow device for example of a mixer, is understood to mean the smallest dimension at right angles to the flow direction.
• the characteristic dimension of a micromixer is significantly smaller than that of a conventional mixer (for example lower at least by the factor of 10 or at least by the factor of 100 or at least by the factor of 1000) and is typically in the micrometer to millimeter range.
• Conventional mixers have a characteristic dimension in the region relevant for the mixing of more than 10 mm, mixers with microstructures, in contrast, of at most 10 mm.
• the characteristic dimension of a mixer with microstructures used in accordance with the invention is preferably in the range from 1 pm to 10 000 pm, more preferably in the range from 10 pm to 5000 pm and especially in the range from 25 pm to 4000 pm.
• the optimal characteristic dimension arises here from the requirements on the mixing quality and the tendency of the mixing apparatus to become blocked.
• chaotic-laminar mixers for example T mixers, Y mixers or cyclone mixers,
• laminar diffusion mixers with convective crossmixing for example shaped mixing channels or channels with secondary structures
• split-recombine mixers for example caterpillar mixers
• the at least one is heated to a temperature of 20 to 90 °C, preferably to a temperature of 30 to 85 °C and especially to a temperature of 40 to 80 °C and is subsequently fed into the at least one continuously operated back-mixed reactor or into a mixer prior to entering the at least one continuously operated back-mixed reactor via at least one feed line.
• the at least one feed line is preferably surrounded by a heat exchanger in order to prevent heat loss.
• the radical polymerization can thus be carried out in at least two steps i) and ii).
• step ii) the polymer-comprising reaction mixture obtained in step i) is then fed to at least one continuously operated further reactor for post-polymerization.
• the at least one continuously operated further reactor which is used for post- polymerization can in principal be any continuously operated reactor known to the person skilled in the art and can be a continuously operated back-mixed reactor or a continuously operated reactor without back-mixing.
• Suitable reactors are, for example, temperature-controllable tubular reactors, plate heat exchangers, loop reactors, stirred tank reactors, slurry reactors, kneader reactors and extruder reactors.
• the at least one continuously operated second reactor can be a conventional reactor or a reactor having a reaction zone with internal cooling and mixing elements.
• At least one further component can then be introduced into the at least one reactor which is located downstream of the at least one continuously operated back-mixed reactor in order to increase the conversion.
• the at least one compound is preferably selected from the at least one olefin ' ically unsaturated acid monomer a), the at least one chain transfer agent b) or the at least one free- radical initiator (P).
• the at least one compound can be fed into the polymer-comprising reaction mixture via the at least one further feed line between steps i) and ii) and/or during step ii).
• a feed stream comprising at least one free-radical initiator (P) and/or at least one chain transfer agent b) is fed into the polymer-comprising reaction mixture between steps i) and ii).
• the radical polymerization in step i) is preferably carried out in a first continuously operated back-mixed reactor and in at least one further continuously operated back-mixed reactor.
• the first and the at least one further continuously operated back-mixed reactors can be any of the continuously operated back-mixed reactors described above.
• the first and the at least one further continuously operated back-mixed reactors are loop reactors.
• the loop reactors in this specific embodiment can be conventional loop reactors or loop reactors with internal cooling and mixing elements.
• step i) If the radical polymerization in step i) is carried out in a first continuously operated back-mixed reactor and at least one further continuously operated back-mixed reactor, the at least one further continuously operated back-mixed reactor is located downstream of the first continuously operated back-mixed reactor and at least one continuously operated further reactor is located downstream of the at least one further continuously operated back-mixed reactor.
• At least one feed line for a liquid feed stream is arranged downstream of the first continuously operated back-mixed reactor and is followed in flow direction by the at least one further continuously operated back-mixed reactor.
• at least one further feed line for a liquid feed stream is arranged downstream of the at least one further continuously operated back-mixed reactor and is followed in flow direction by the continuously operated further reactor.
• the at least one further continuously operated back-mixed reactor may also comprise at least one feed line for a liquid feed stream, which is directly adjoined to the at least one further continuously operated back-mixed reactor.
• the at least one further continuously operated back-mixed reactor is a reactor cascade comprising two or more further continuously operated back-mixed reactors and at least one feed line for a liquid feed stream is arranged downstream of the first continuously operated back-mixed reactor and is followed in flow direction by the first reactor of the reactor cascade.
• One further feed stream is then arranged downstream of the last reactor of the reactor cascade and is followed in flow direction by the continuously operated further reactor.
• further feed lines for a liquid feed stream are preferably arranged downstream of each reactor of the reactor cascade and are followed in flow direction by the next reactor of the reactor cascade and/or further feed lines are directly adjoined to one or more reactors of the reactor cascade.
• At least one further component selected from the at least one olefinically unsaturated acid monomer a), the at least one chain transfer agent b), the at least one free-radical initiator (P) or the at least one further monomer d) to m) can then be introduced into the polymer-comprising reaction mixture downstream of each continuously operated back- mixed reactor via any one or more of the feed lines described above in order to increase the conversion.
• said arrangement allows for the precise control over the monomer ratios in the polymer-comprising reaction mixture and further improves the product homogeneity of the resulting polymer composition.
• At least one further component selected from the at least one chain transfer agent b) or the at least one free-radical initiator (P) can be introduced into the continuously operated further reactor which is located downstream of the at least one further continuously operated back-mixed reactor in order to increase the conversion.
• the at least one compound can be fed into the continuously operated further reactor via the at least one further feed line downstream of the at least one further continuously operated back-mixed reactor between steps i) and ii) and/or via at least one feed line directly adjoined to the continuously operated further reactor during step ii).
• the invention is illustrated hereinafter by the examples.
• the Nu number is calculated according to
• the data for the loop reactor with internal cooling and mixing elements (herein further referred to as milli-loop reactor) according to Example E1 were calculated for a continuously operated loop reactor with internal cooling and mixing elements with a production scale of 4 kt of polymer composition per year. Instead of the feeding time, the residence time in the loop was used for the calculations. Likewise, the batch size relates to the reactor hold-up in the loop.
• the actual heat transfer coefficient ⁇ act of 250 W/m 2 K is a typical specification for Fluitec CSE-XR static mixer heat exchangers.
• the semibatch reactors of comparative examples CE1 to CE4 are not operated continuously. The respective data are shown in Table 1.
• the ratio of both heat transfer coefficients is only 0.48 for a milli-loop reactor (see Example E1).
• the milli-loop reactor shows an even smaller ratio of the heat transfer coefficients compared to very low-scale semibatch reactions of 0.72, as shown in comparative example CE1.
• the maximum theoretical extent of a given mass transfer is typically determined by the point at which the reaction mixture exhibits a uniform concentration of all compounds.
• the characteristic reaction time i.e. the monomer half-life for a first-order reaction
• the data for the milli-loop reactor according to Example E2 were calculated for a continuously operated milli-loop reactor with a production scale of 4 kt of polymer composition per year. Instead of the feeding time, the residence time in the loop was used for the calculations. Likewise, the batch size relates to the reactor hold-up in the loop.
• the mixing time W of 0.15 mm is the time the reaction mixture needs to pass 13 mixing elements at a loop flow velocity of 17.5 m/min.
• the semibatch reactors of comparative examples CE5 to CE8 are not operated continuously. Table 2
• the characteristic reaction time should be at least one magnitude larger than the characteristic mixing time Due to the high polymerization rate of acrylic acid, this criterion is difficult to meet, however, the above results show that a milli-loop reactor shows superior properties in this regard with a ratio of of 7.3 (see Example E2)
• the radical polymerization for the preparation of polymer compositions according to the invention involves two continuously operated reactors, a loop reactor and a subsequent tubular reactor.
• the at least one olefinically unsaturated acid monomer a), the at least one chain transfer agent b) and the at least one polyether compound (PE) are fed into a Fluitec CSE-X/4G static mixer via different feed lines prior to being dosed into the loop reactor via a feed line.
• the at least one polyether compound (PE) is provided at a temperature of 80 °C and the feed line comprising the at least one polyether compound (PE) and the feed connecting the Fluitec CSE-X/4G static mixer and the loop reactor is surrounded by a heat exchanger.
• the at least one free-radical initiator (P) is fed into the loop reactor at a second dosing point as a solution in the at least one solvent (S) via another feed line.
• Another dosing point for mixtures of the at least one free-radical initiator (P) and/or the at least one chain transfer agent b) is placed between the loop reactor and the following tubular reactor.
• the molecular weight can be tuned by variation of the amount of the at least one chain transfer agent b).
• the amount of the initiator (P) has significant impact on the molecular weight, as increasing starter concentrations lead to a reduced monomer concentration in the loop reactor and thus, to lower molecular weights (see Examples 3c and 3d). Further addition of the initiator (P) after the loop reactor showed no effect on conversion and molar mass distribution, indicating that the residual starter concentration after the loop reactor is considerably high.
• Examples 4 A set of polymerization reactions was performed at a temperature of 80 "C by polymerizing acrylic acid (monomer component a)), methacrylic acid (monomer component a)) and sodium hypophosphite (monomer component b)) in the presence of PEO (polyether compound (PE)) and 2,2 , -Azobis-2-(amidinopropane)-dihydrochloride (free-radical initiator (P)) in water (solvent (S)).
• the reaction mixture used for these experiments comprises the following components:
• Copolymerization reactions of acrylic acid and methacrylic acid yield products with high molecular weights (M w > 29 kg/mol) and broad molecular weight distributions.
• the Examples 4a to 4d show nearly complete conversion of methacrylic acid in the loop reactor, and slightly lower conversion of acrylic acid (97 to 99%).
• applying longer residence times in the loop reactor reduces the obtained molecular weight and polydispersity.
• the chain transfer agent b) also reduces the obtained molecular weight and polydispersity but the effect of higher concentrations of the chain transfer agent b) is relatively subtle compared to the effect of the residence times. Accordingly, the molecular weight and the polydispersity of the polymer can be adjusted within a wide range by variation of these parameters.
• a set of polymerization reactions was performed at a temperature of 80 °C by polymerizing acrylic acid (monomer component a)) and sodium hypophosphite (monomer component b)) in the presence of PEO (polyether compound (PE)) and tert- butyl peroxypivalate (free-radical initiator (P)).
• PEO polyether compound
• P free-radical initiator
• the ratio of acrylic acid to PEO is 1.75.
• the reaction mixture used for these experiments comprises the following components:
• Example 5e additionally shows the preparation of polymer compositions in which the solids content is above 65%.
• the preparation of polymer compositions in semi-batch reactors is not feasible under these conditions.
• the loop pressure drop increases to approximately 20 bar with a solid content above 65%, the run can be performed without problems.
• the loop pressure drop of 20 bar represents the upper limit for the used Gather gear pump; however, with the use of different loop pumps even significantly higher solid contents are accessible.

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• 2017
  • 2017-08-01 WO PCT/EP2017/069406 patent/WO2018029038A1/en unknown
  • 2017-08-01 EP EP17745742.1A patent/EP3497138A1/de not_active Withdrawn
  • 2017-08-01 CN CN201780056105.0A patent/CN109689704A/zh active Pending
  • 2017-08-01 RU RU2019106490A patent/RU2019106490A/ru not_active Application Discontinuation

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