Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/08—Removal of fats, resins, pitch or waxes; Chemical or physical purification, i.e. refining, of crude cellulose by removing non-cellulosic contaminants, optionally combined with bleaching
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/02—Agents for preventing deposition on the paper mill equipment, e.g. pitch or slime control
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/35—Polyalkenes, e.g. polystyrene
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/36—Polyalkenyalcohols; Polyalkenylethers; Polyalkenylesters
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/54—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen
  • D21H17/55—Polyamides; Polyaminoamides; Polyester-amides
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/16—Sizing or water-repelling agents

Definitions

• the invention relates to a process for reducing deposits in the dry section in the production of paper, board and cardboard by adding (a) at least one water-soluble cationic polymer and (b) at least one aqueous dispersion of a polymer size to a paper stock, draining the paper stock with sheet formation and drying the paper products.
• U.S. Pat. No. 3,081,219 discloses a process for the production of paper based on sulfite groundwood, in which control of the deposits of impurities is to be achieved by the addition of a sequestering agent, such as polyphosphates, or of a dispersant, such as formaldehyde sulfonic acid or naphthalenesulfonic acid-formaldehyde condensate.
• a sequestering agent such as polyphosphates
• a dispersant such as formaldehyde sulfonic acid or naphthalenesulfonic acid-formaldehyde condensate.
• U.S. Pat. No. 4,871,865 describes a process for the production of paper in which a water-soluble polymer having methyl ether groups, such as, for example, methylcellulose, is added in order to achieve control of the deposits of stickies.
• DE 42 40 110 A1 discloses a process for the production of paper in which control of the impurity deposits is brought about by the addition of water-soluble polyethyleneimines.
• This process should be suitable in particular for newspapers and cardboard produced from wastepaper (comprising deinked wastepaper).
• the object is achieved by a process for reducing deposits in the dry section in the production of paper, board and cardboard by adding (a) at least one water-soluble cationic polymer and (b) at least one aqueous dispersion of a polymer size to a paper stock, draining the paper stock with sheet formation and drying the paper products.
• Said components (a) and (b) can be added to the paper stock in any desired sequence or as a mixture.
• the cationic polymers (a) are water-soluble.
• the solubility in water under standard conditions (20° C., 1013 mbar) and at pH 7 is, for example, at least 5% by weight, preferably at least 10% by weight.
• the charge density of the cationic polymers (without counterion) is, for example, at least 0.5 meq/g and is usually in the range from 1 to 22 meq/g.
• Water-soluble cationic polymers (a) in the context of the invention are those polymers which may comprise cationic, neutral or anionic structural units, but in which the cationic structural units have an excess of at least 5 mol %, preferably of at least 10 mol % and particularly preferably of at least 20 mol % compared with the anionic structural units.
• the molar masses M w of the cationic polymers are, for example, at least 1000 dalton. They are, for example, generally in the range from 5000 to 5 million dalton.
• Suitable water-soluble cationic polymers are all compounds carrying amino or ammonium groups.
• the amino groups may be primary, secondary, tertiary or quaternary groups.
• Substantially polymers, polyaddition compounds or polycondensates are suitable for the polymers, it being possible for the polymers to have a linear or branched structure including hyperbranched or dendritic structures.
• graft polymers can also be used.
• the water-soluble cationic polymer (a) is usually selected from the group consisting of the polymers comprising vinylamine units, cationic homo- and copolymers of (meth)acrylamide, polyallylamines, polyaminoalkyl vinyl ethers, polyamidoamine compounds and polyamine compounds reacted with epihalohydrin, amphoteric polymers having an overall cationic charge, polymers comprising ethyleneimine units and homopolymers having cationic or protonatable groups.
• Such water-soluble cationic polymers (a) are, for example, polymers comprising vinylamine units, cf. DE 35 06 832 A1 and DE 10 2004 056 551 A1.
• reaction products which are obtainable
• reaction products which are obtainable by polymerization of
• reaction products which are obtainable by polymerization of N-vinylformamide and subsequent elimination of formyl groups from the vinylformamide units incorporated in the form of polymerized units into the polymer, with formation of amino groups, are used as polymers comprising vinylamine units or the reaction products which are obtainable by copolymerization of
• the polymers comprising vinylamine units may also be amphoteric if they have a total cationic charge.
• the content of cationic groups in the polymer should be at least 5 mol %, preferably at least 10 mol %, above the content of anionic groups.
• Such polymers are obtainable, for example, by polymerization of
• amphoteric polymers which comprise vinylamine units, carry an overall cationic charge and are obtainable, for example, by copolymerization of
• Examples of monomers of the formula (I) are N-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N-vinyl-N-ethylacetamide, N-vinylpropionamide and N-vinyl-N-methylpropionamide and N-vinylbutyramide.
• the monomers of group (a) can be used alone or as a mixture in the copolymerization with the monomers of the other groups.
• a preferably used monomer of this group is N-vinylformamide.
• polymers may optionally be modified by copolymerizing the N-vinylcarboxamides (1.) together with (2.) at least one other monoethylenically unsaturated monomer and then hydrolyzing the copolymers with formation of amino groups. If anionic monomers are used in the copolymerization, the hydrolysis of the vinylcarboxamide units incorporated in the form of polymerized units is continued until the molar excess of amine units relative to the anionic units in the polymer is at least 5 mol %.
• Examples of monomers of the group (2.) are esters of ⁇ , ⁇ -ethylenically unsaturated mono- and dicarboxylic acids with C 1 -C 30 -alkanols, C 2 -C 30 -alkanediols and C 2 -C 30 -aminoalcohols, amides of ⁇ , ⁇ -ethylenically unsaturated monocarboxylic acids and the N-alkyl and N,N-dialkyl derivatives thereof, nitriles of ⁇ , ⁇ -ethylenically unsaturated mono- and dicarboxylic acids, esters of vinyl alcohol and allyl alcohol with C 2 -C 30 -monocarboxylic acids, N-vinyllactams, nitrogen-containing heterocycles having ⁇ , ⁇ -ethylenically unsaturated double bonds, vinylaromatics, vinyl halides, vinylidene halides, C 2 -C 8 -monoolefins and mixture
• Suitable representatives are, for example, methyl(meth)acrylate (in which (meth)acrylate in the context of the present invention denotes both acrylate and methacrylate), methyl ethacrylate, ethyl(meth)acrylate, ethyl ethacrylate, n-butyl (meth)acrylate, isobutyl(meth)acrylate, tert-butyl(meth)acrylate, tert-butyl ethacrylate, n-octyl(meth)acrylate, 1,1,3,3-tetramethylbutyl(meth)acrylate, ethylhexyl (meth)acrylate and mixtures thereof.
• Suitable additional monomers of group (2.) are furthermore the esters of ⁇ , ⁇ -ethylenically unsaturated mono- and dicarboxylic acids with aminoalcohols, preferably C 2 -C 12 -aminoalcohols. These may be C 1 -C 8 -monoalkylated or -dialkylated on the amine nitrogen.
• Suitable acid components of these esters are, for example, acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, crotonic acid, maleic anhydride, monobutyl maleate and mixtures thereof. Acrylic acid, methacrylic acid and mixtures thereof are preferably used.
• N-methylaminomethyl(meth)acrylate N-methylaminoethyl(meth)acrylate, N,N-dimethylaminomethyl (meth)acrylate, N,N-dimethylaminoethyl(meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl(meth)acrylate, N,N-diethylaminopropyl (meth)acrylate and N,N-dimethylaminocyclohexyl(meth)acrylate.
• 2-hydroxyethyl(meth)acrylate, 2-hydroxyethyl ethacrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl(meth)acrylate, 6-hydroxyhexyl(meth)acrylate and mixtures thereof are suitable as monomers of group (2.).
• Suitable additional monomers of group (2.) are furthermore acrylamide, methacrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-butyl(meth)acrylamide, N-(tert-butyl)(meth)acrylamide, N-octyl(meth)acrylamide, N-(1,1,3,3-tetramethylbutyl)(meth)acrylamide, N-(ethylhexyl)(meth)acrylamide and mixtures thereof.
• monomers of group (2.) are nitriles of ⁇ , ⁇ -ethylenically unsaturated mono- and dicarboxylic acids, such as, for example, acrylonitrile and methacrylonitrile.
• nitriles of ⁇ , ⁇ -ethylenically unsaturated mono- and dicarboxylic acids such as, for example, acrylonitrile and methacrylonitrile.
• amidine units cf., for example, EP 0 528 409 A1 or DE 43 28 975 A1.
• amidine units are in fact formed in a secondary reaction in that the vinylamine units react with a neighboring vinylformamide unit or—if a nitrile group is present as a neighboring group of the polymer—react therewith.
• the statement “vinylamine units in the amphoteric copolymers or in unmodified homo- or copolymers” always means the sum of vinylamine and amidine units.
• Suitable monomers of group (2.) are furthermore N-vinyllactams and derivatives thereof which may have, for example, one or more C 1 -C 6 -alkyl substituents (as defined above). These include 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 and mixtures thereof.
• N-vinylimidazoles and alkylvinylimidazoles are suitable as monomers of group (2.), in particular methylvinylimidazoles, such as, for example, 1-vinyl-2-methylimidazole, 3-vinylimidazole N-oxide, 2- and 4-vinylpyridine N-oxides and betaine derivatives and quaternization products of these monomers and ethylene, propylene, isobutylene, butadiene, styrene, ⁇ -methylstyrene, vinyl acetate, vinyl propionate, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride and mixtures thereof.
• methylvinylimidazoles such as, for example, 1-vinyl-2-methylimidazole, 3-vinylimidazole N-oxide, 2- and 4-vinylpyridine N-oxides and betaine derivatives and quaternization products of these monomers and ethylene, propylene, is
• the abovementioned monomers can be used individually or in the form of any desired mixtures. Typically, they are used in amounts of from 1 to 90 mol %, preferably from 10 to 80 mol % and particularly preferably from 10 to 60 mol %.
• anionic monomers which are designated above as monomers (2.1), are also suitable as other monoethylenically unsaturated monomers of group (2.). They can, optionally, be copolymerized with the neutral and/or cationic monomers (2.2) described above.
• the amount of anionic monomers (2.1) is, however, not more than 45 mol %, so that the resulting amphoteric copolymer has a cationic charge overall.
• anionic monomers of group (2.1) are ethylenically unsaturated C 3 - to C 8 -carboxylic acids, such as, for example, acrylic acid, methacrylic acid, dimethacrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid, mesaconic acid, citraconic acid, methylenemalonic acid, allylacetic acid, vinylacetic acid and crotonic acid.
• Other suitable monomers of this group are monomers comprising sulfo groups, such as vinylsulfonic acid, acrylamido-2-methylpropanesulfonic acid and styrenesulfonic acid, and monomers comprising phosphonic groups, such as vinylphosphonic acid.
• the monomers of this group can be used alone or as a mixture with one another, in partly or completely neutralized form in the copolymerization.
• alkali metal or alkaline earth metal bases, ammonia, amines and/or alkanolamines are used for the neutralization.
• alkali metal or alkaline earth metal bases, ammonia, amines and/or alkanolamines are used for the neutralization.
• these are sodium hydroxide solution, potassium hydroxide solution, sodium carbonate, potassium carbonate, sodium bicarbonate, magnesium oxide, calcium hydroxide, calcium oxide, triethanolamine, ethanolamine, morpholine, diethylenetriamine or tetraethylenepentamine.
• a further modification of the copolymers is possible by using, in the copolymerization, monomers of group (3.) which comprise at least two double bonds in the molecule, e.g. triallylamine, methylenebisacrylamide, glycol diacrylate, glycol dimethacrylate, glyceryl triacrylate, pentaerythrityl triallyl ether, polyalkylene glycols at least diesterified with acrylic acid and/or methacrylic acid or polyols, such as pentaerythritol, sorbitol or glucose. These are so-called crosslinking agents. If at least one monomer of the above group is used in the polymerization, the amounts used are up to 2 mol %, e.g. from 0.001 to 1 mol %.
• chain-transfer agents for example sulfur compounds such as mercaptoethanol, 2-ethylhexyl thioglycolate, thioglycolic acid and dodecyl mercaptan, and sodium hypophosphite, formic acid or tribromochloromethane and terpinolene, can be used.
• the polymers comprising vinylamine units also include hydrolyzed graft polymers of, for example, N-vinylformamide on polyalkylene glycols, polyvinyl acetate, polyvinyl alcohol, polyvinylformamides, polysaccharides, such as starch, oligosaccharides or monosaccharides.
• the graft polymers are obtainable, for example, by subjecting N-vinylformamide to free radical polymerization in an aqueous medium in the presence of at least one of said grafting bases, optionally together with copolymerizable other monomers, and then hydrolyzing the grafted-on vinylformamide units in a known manner to give vinylamine units.
• the hydrolysis of the copolymers described above can be carried out in the presence of acids or bases or enzymatically.
• the vinylamine groups forming from the vinylcarboxamide units are present in salt form.
• the hydrolysis of vinylcarboxamide copolymers is described in detail in EP 0 438 744 A1, page 8, line 20 to page 10, line 3. The statements made there apply correspondingly to the preparation of the purely cationic and/or amphoteric polymers comprising vinylamine units to be used according to the invention and having an overall cationic charge.
• polymers comprising vinylamine units are the reaction products which are obtainable by Hofmann degradation of homo- or copolymers of acrylamide or of methacrylamide in an aqueous medium in the presence of sodium hydroxide solution and sodium hypochlorite and subsequent decarboxylation of the carbamate groups of the reaction products in the presence of an acid.
• Such polymers are disclosed, for example, in EP 0 377 313 and WO 2006/075115 A1.
• the preparation of polymers comprising vinylamine groups is discussed in detail, for example, in WO 2006/075115 A1, page 4, line 25 to page 10, line 22 and in the examples on pages 13 and 14.
• polymers which comprise acrylamide and/or methacrylamide units are used as starting materials. These are homo- or copolymers of acrylamide and methacrylamide. Suitable comonomers are, for example, dialkylaminoalkyl(meth)acrylamides, diallylamine, methyldiallylamine and the salts of the amines and the quaternized amines.
• comonomers are dimethyldiallylammonium salts, acrylamidopropyltrimethylammonium chloride and/or methacrylamidopropyltrimethyl-ammonium chloride, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, vinyl acetate and acrylates and methacrylates.
• other suitable comonomers are anionic monomers, such as acrylic acid, methacrylic acid, maleic anhydride, maleic acid, itaconic acid, acrylamidomethylpropanesulfonic acid, methallylsulfonic acid and vinylsulfonic acid and the alkali metal, alkaline earth metal and ammonium salts of said acidic monomers, not more than 5 mol % of these monomers being used in the polymerization.
• the amount of water-insoluble monomers is chosen in the polymerization so that the resulting polymers are soluble in water.
• crosslinking agents may also be used as comonomers, for example ethylenically unsaturated monomers which comprise at least two double bonds in the molecule, such as triallylamine, methylenebisacrylamide, ethylene glycol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, triallylamine and trimethylol trimethacrylate.
• a crosslinking agent is used, the amounts used are, for example, from 5 to 5000 ppm.
• the polymerization of the monomers can be effected by all known processes, for example by free radical solution, precipitation or suspension polymerization.
• the procedure can be effected in the presence of customary polymerization chain-transfer agents.
• aqueous solutions of at least one polymer comprising acrylamide and/or methacrylamide units are used as starting material.
• the ratio of alkali metal hypochlorite to (meth)acrylamide units in the polymer is decisive for the resulting content of amine groups in the polymer.
• the molar ratio of alkali metal hydroxide to alkali metal hypochlorite is, for example, from 2 to 6, preferably from 2 to 5.
• the amount of alkali metal hydroxide required for the degradation of the polymer is calculated for a certain amine group content in the degraded polymer.
• the Hofmann degradation of the polymer takes place, for example, in the temperature range from 0 to 45° C., preferably from 10 to 20° C., in the presence of quaternary ammonium salts as stabilizer, in order to prevent a secondary reaction of the resulting amino groups with the amide groups of the starting polymer.
• the aqueous reaction solution is passed into a reactor in which an acid for the decarboxylation of the reaction product is present.
• the pH of the reaction product comprising vinylamine units is adjusted to a value of from 2 to 7.
• the concentration of the degradation product comprising vinylamine units is, for example, more than 3.5% by weight, in general above 4.5% by weight.
• the aqueous polymer solutions can be concentrated, for example, with the aid of ultrafiltration.
• water-soluble cationic polymers (a) are cationic homo- and copolymers of (meth)acrylamide and can be prepared by polymerization of the above-described monomers of group (2.), the quaternization products of these monomers with C 1 - to C 8- alkyl chloride, C 1 -C 8 -dialkyl sulfate, C 1 -C 16 -epoxides and benzyl chloride also being suitable.
• Monomers or monomer mixtures in which the number average of m is at least 2.1, in general from 2.1 to 8, in the abovementioned formula (II) are preferred. They are obtainable by reacting an ethylenically unsaturated carboxylic acid with an oligoalkyleneimine, preferably in the form of an oligomer mixture. The resulting product can, optionally, be converted into the acid addition salt with a mineral acid HY. Such monomers can be polymerized in an aqueous medium in the presence of an initiator which initiates a free radical polymerization, to give cationic homo- and copolymers.
• water-soluble cationic polymers (a) are polyaminoalkyl vinyl ethers.
• Monomers suitable for this purpose are disclosed in the prior EP application with the application number 07 117 909.7. They are aminoalkyl vinyl ethers comprising alkyleneimine units and of the formula (III)
• [Al—] is a linear or branched oligoalkyleneimine chain having n alkyleneimine units, n is a number of at least 1 and X is a straight-chain or branched C 2 - to C 6 -alkylene group, and salts of the monomers (III) with mineral acids or organic acids and quaternization products of the monomers (III) with alkyl halides or dialkyl sulfates.
• These compounds are obtainable by an addition reaction of alkyleneimines with amino-C 2 - to C 6 -alkyl vinyl ethers.
• the abovementioned monomers can be polymerized alone to give water-soluble cationic homopolymers (a) or together with at least one other neutral monomer to give water-soluble cationic copolymers or with at least one monomer having acid groups to give amphoteric copolymers which, in the case of a molar excess of cationic monomers incorporated in the form of polymerized units, carry an overall cationic charge.
• Suitable neutral monomers which are copolymerized with the abovementioend cationic monomers for the preparation of cationic polymers are, for example, esters of ⁇ , ⁇ -ethylenically unsaturated mono- and dicarboxylic acids with C 1 -C 30 -alkanols, C 2 -C 30 -alkanediols, amides of ⁇ , ⁇ -ethylenically unsaturated monocarboxylic acids and the N-alkyl and N,N-dialkyl derivatives thereof, esters of vinyl alcohol and allyl alcohol with saturated C 1 -C 30 -monocarboxylic acids, vinylaromatics, vinyl halides, vinylidene halides, C 2 - to C 8 -monoolefins and mixtures thereof.
• Suitable comonomers are, for example, methyl(meth)acrylate, methyl ethacrylate, ethyl(meth)acrylate, ethyl ethacrylate, n-butyl(meth)acrylate, isobutyl (meth)acrylate, tert-butyl(meth)acrylate, tert-butyl ethacrylate, n-octyl(meth)acrylate, 1,1,3,3-tetramethylbutyl(meth)acrylate, ethylhexyl(meth)acrylate and mixtures thereof.
• acrylamide, substituted acrylamides, methacrylamide, substituted methacrylamides such as, for example, acrylamide, methacrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-(n-butyl)(meth)acrylamide, tert-butyl(meth)acrylamide, n-octyl(meth)acrylamide, 1,1,3,3-tetramethylbutyl(meth)acrylamide and ethylhexyl(meth)acrylamide, and acrylonitrile and methacrylonitrile and mixtures of said monomers.
• Further monomers for the modification of the cationic polymers are 2-hydroxyethyl (meth)acrylate, 2-hydroxyethyl ethacrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, 3-hydroxybutyl(meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl(meth)acrylate, etc. and mixtures thereof.
• N-vinyllactams and derivatives thereof which may have, for example, one or more C 1 -C 6 -alkyl substituents, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, 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 comonomers for the copolymerization with the abovementioned cationic monomers are furthermore ethylene, propylene, isobutylene, butadiene, styrene, ⁇ -methylstyrene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride and mixtures thereof.
• polyamidoamine compounds and polyamine compounds reacted with epihalohydrin are also suitable.
• Polyamine compounds reacted with epihalohydrin are disclosed, for example, in U.S. Pat. No. 3,258,393. According to this, epichlorohydrin is reacted with a bifunctional or a polyfunctional amine.
• Suitable bifunctional amines are methylamine, ethylamine, ethanolamine, dimethylamine, N,N′-dimethylethylenediamine, aniline, piperazine and ethyl aminoacetate.
• Examples of polyfunctional amines are ethylenediamine, N-methylethylenediamine, ammonia, hydrazine, p-phenylenediamine and further amines mentioned in U.S. Pat. No. 3,258,393, in particular the polyfunctional amines disclosed in column 4.
• the bifunctional and polyfunctional amines are usually used in equimolar ratio.
• other crosslinking agents such as glyoxal, 1,2-dichloroethane, diglycidyl ether, methylenebisacrylamide and 1,4-dichlorobutene, and further crosslinking agents mentioned in column 4 of U.S. Pat. No. 3,258,393 are also suitable according to this US document.
• crosslinking agents such as glyoxal, 1,2-dichloroethane, diglycidyl ether, methylenebisacrylamide and 1,4-dichlorobutene, and further crosslinking agents mentioned in column 4 of U.S. Pat. No. 3,258,393 are also suitable according to this US document.
• polyamine compounds reacted with epihalohydrin can be prepared on the basis of only one bifunctional amine or of a polyfunctional amine.
• cationic polymers are also understood as meaning amphoteric polymers which carry an overall cationic charge.
• the content of cationic groups is, for example, at least 5 mol % above the content of anionic groups in the polymer.
• Such polymers are obtainable, for example, by copolymerizing a cationic monomer, such as N,N-dimethylaminoethylacrytamide, in the form of the free base, in a form partly neutralized with an acid or in quaternized form with at least one monomer comprising acid groups, the cationic monomer being used in a molar excess so that the resulting polymers carry an overall cationic charge.
• polymers comprising ethyleneimine units are suitable as water-soluble cationic polymers for the process according to the invention.
• These include all polymers which are obtainable by polymerization of ethyleneimine in the presence of acids, Lewis acids or haloalkanes, such as homopolymers of ethyleneimine or graft polymers of ethyleneimine, cf. U.S. Pat. No. 2,182,306 or U.S. Pat. No. 3,203,910. These polymers can, optionally, be subsequently subjected to crosslinking.
• Suitable crosslinking agents are, for example, all polyfunctional compounds which comprise groups reactive toward primary amino groups, for example polyfunctional epoxides, such as bisglycidyl ethers of oligo- or polyethylene oxides, or other polyfunctional alcohols, such as glycerol or sugars, polyfunctional carboxylic esters, polyfunctional isocyanates, polyfunctional acrylates or methacrylates, polyfunctional acrylamides or methacrylamides, epichlorohydrin, polyfunctional acid halides, polyfunctional nitriles, ⁇ , ⁇ -chlorohydrin ethers of oligo- or polyethylene oxides or of other polyfunctional alcohols, such as glycerol or sugars, divinyl sulfone, maleic anhydride or ⁇ -halocarboxylic acid chlorides, polyfunctional haloalkanes, in particular ⁇ , ⁇ -dichloroalkanes. Further crosslinking agents are described in WO 97/25367 A1, pages 8 to 16.
• Polymers comprising ethyleneimine units are disclosed, for example, in EP 0 411 400 A1, DE 24 34 816 A1 and U.S. Pat. No. 4,066,494.
• At least one water-soluble cationic polymer from the group consisting of
• Polymers which are obtained by first condensing at least one polycarboxylic acid with at least one polyamine to give polyamidoamines, then effecting grafting with ethyleneimine and then crosslinking the reaction products with one of the abovementioned compounds are among the preferred compounds comprising polyethleneimine units.
• a process for the preparation of such compounds is described, for example, in DE 24 34 816 A1, ⁇ , ⁇ -chlorohydrin ethers of oligo- or polyethylene oxides being used as crosslinking agents.
• Reaction products of polyethyleneimines with monobasic carboxylic acids to give amidated polyethyleneimines are disclosed in WO 94/12560 A1.
• Michael adducts of polyethyleneimines with ethylenically unsaturated acids, salts, esters, amides or nitriles of monoethylenically unsaturated carboxylic acids form the subject of WO 94/14873 A1.
• Phosphonomethylated polyethyleneimines are described in detail in WO 97/25367 A1.
• Carboxylated polyethyleneimines are obtainable, for example, with the aid of a Stecker synthesis by reaction of polyethyleneimines with formaldehyde and ammonia/hydrogen cyanide and hydrolysis of the reaction products.
• Alkoxylated polyethyleneimines can be prepared by reacting polyethyleneimines with alkylene oxides, such as ethylene oxide and/or propylene oxide.
• homopolymers of cationic or basic (meth)acrylates which in each case have an amino group and/or quaternary ammonium group, or cationic or basic (meth)acrylamides which in each case carry an amino group and/or quaternary ammonium group may also be used in the process according to the invention.
• Such compounds having an amino group are those of the general formula (IV):
• A is O, NH,
• B is C n H 2n , where n is an integer in the range from 1 to 8, R 1 , R 2 are C m H 2m+1 , m is an integer in the range from 1 to 4 and
• R 3 is H, CH 3 .
• X— is OH—, Cl—, Br, CH 3 —OSO 3 —
• R 4 is C m H 2m+1 , m is an integer in the range from 1 to 4, and the other substituents have the abovementioned meaning.
• the compounds of the formula (V) are designated as a rule as cationic monomers and those of the formula (IV) as basic monomers.
• Basic, ethylenically unsaturated monomers are, for example, acrylates and methacrylates of aminoalcohols, e.g.
• the quaternary compounds of the formula (V) are obtained by reacting the basic monomers of the formula (IV) with known quaternizing agents, for example with methyl chloride, benzyl chloride, ethyl chloride, butyl bromide, dimethyl sulfate and diethyl sulfate or epichlorohydrin. These monomers lose their basic character in the quaternary form.
• N,N,N-trimethylammoniumethyl acrylate chloride N,N,N-trimethylammoniumethyl methacrylate chloride, N,N,N-trimethylammoniumethylmethacrylamide chloride, N,N,N-trimethylammoniumpropylacrylamide chloride, N,N,N-trimethylammoniumpropylmethacrylamide chloride, N,N,N-trimethylammoniumethylacrylamide chloride and the corresponding methosulfates and sulfates.
• the monomers of this group are preferably selected from N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminoethyl methacrylate, and N,N-dimethylaminoethyl acrylate, used in each case in the form of a salt with at least one mineral acid or carboxylic acid and/or in quaternary form.
• a preferred quaternizing agent is methyl chloride.
• All of the abovementioned cationic homo- and copolymers can be prepared by solution, precipitation, suspension or emulsion polymerization.
• the solution polymerization in aqueous media is preferred.
• Suitable aqueous media are water and mixtures of water and at least one water-miscible solvent, for example an alcohol, such as methanol, ethanol, n-propanol, etc.
• the polymerization temperatures are preferably in a range from about 30 to 200° C., particularly preferably from 40 to 110° C. Polymerization is usually effected under atmospheric pressure but may also take place under reduced or superatmospheric pressure. A suitable pressure range is from 0.1 to 5 bar.
• the monomers can be polymerized with the aid of free radical initiators.
• Initiators which may be used for the free radical polymerization are the peroxo and/or azo compounds customary for this purpose, for example alkali metal or ammonium peroxodisulfates, diacetyl peroxide, dibenzoyl peroxide, succinyl peroxide, di-tert-butyl peroxide, tert-butyl perbenzoate, tert-butyl perpivalate, tert-butyl peroxy-2-ethyl-hexanoate, tert-butyl permaleate, cumyl hydroperoxide, diisopropyl peroxodicarbamate, bis(o-toluoyl)peroxide, didecanoyl peroxide, dioctanoyl peroxide, dilauroyl peroxide, tert-butyl perisobutyrate, tert-butyl peracetate, di-tert-amyl peroxide, tert
• Initiator mixtures or redox initiator systems such as, for example, ascorbic acid/iron(II) sulfate/sodium peroxodisulfate, tert-butyl hydroperoxide/sodium disulfite, tert-butyl hydroperoxide/sodium hydroxymethanesulfinate, H 2 O 2 /Cu(I) or iron(II) compounds, are also suitable.
• the polymerization can be effected in the presence of at least one chain-transfer agent.
• chain-transfer agent e.g. sulfur compounds, e.g. mercaptoethanol, 2-ethylhexyl thioglycolate, thioglycolic acid, sodium hypophosphite, formic acid or dodedyl mercaptan and tribromochloromethane and other compounds which have a regulating effect on the molecular weight of the polymers obtained, can be used as chain-transfer agents.
• All abovementioned cationic polymers can be modified by carrying out the polymerization of the cationic monomers and, optionally, of the mixtures of cationic monomers and the comonomers in the presence of at least one crosslinking agent.
• the crosslinking agents are understood as meaning those monomers which comprise at least two double bonds in the molecule, e.g. methylenebisacrylamide, glycol diacrylate, glycol dimethacrylate, glyceryl triacrylate, pentaerythrityl triallyl ether, polyalkylene glycols at least diesterified with acrylic acid and/or methacrylic acid or polyols, such as pentaerythritol, sorbitol or glucose.
• the amounts used are, for example, up to 2 mol %, for example from 0.001 to 1 mol %.
• the cationic polymers can be modified by the subsequent addition of crosslinking agents, i.e. by the addition of compounds which have at least two groups reactive toward amino groups, such as, for example,
• the at least one water-soluble cationic polymer (a) is used in the process according to the invention for reducing deposits in the dry section in the production of paper, for example in an amount of from 0.005 to 2.0% by weight, preferably from 0.005 to 1% by weight, particularly preferably from 0.01 to 0.3% by weight, based in each case on the solids content of the paper stock.
• Finely divided, cationic or amphoteric, aqueous polymer dispersions which are frequently obtainable by a two-stage polymerization, are preferably suitable.
• a prepolymer is prepared as a dispersant or protective colloid and an emulsion polymerization is then carried out in an aqueous solution of the prepolymer in the presence of ethylenically unsaturated monomers.
• Such finely divided, cationic, aqueous polymer dispersions are known to the person skilled in the art and are disclosed, inter alia, in DE 24 25 585 A1, DE 24 54 397 A1, EP 0 051 144 A1, EP 0 058 313 A1, U.S. Pat. No. 4,659,431, EP 1 180 527 A1, WO 05/121195 A1, WO 08/071,690 A1 and in the prior EP application with the application number 09 161 929.6.
• the prepolymer obtained by this route is then subjected to an emulsion polymerization as a dispersant or protective colloid in the presence of ethylenically unsaturated monomers, a monomer mixture comprising nonionic, hydrophobic, ethylenically unsaturated monomers being used as the ethylenically unsaturated monomers.
• Suitable (i) nitrogen-containing monomers which carry an amino group and/or quaternary ammonium group are those compounds which are used beforehand with the formulae (IV) and (V) as (a) water-soluble cationic polymers for the preparation of homopolymers of cationic or basic (meth)acrylates, which in each case have an amino group and/or quaternary ammonium group, or cationic or basic (meth)acrylamides, which in each case carry an amino group and/or quaternary ammonium group.
• the abovementioned preferred compounds and the quaternization products thereof are also preferably used as (i) nitrogen-containing monomers.
• the monomers of group (ii) for the preparation of the prepolymer are nonionic, hydrophobic, ethylenically unsaturated compounds. They are those monomers which are not markedly soluble in water and form hydrophobic polymers. Such monomers are, for example, vinylaromatic monomers, such as styrene and substituted styrenes, e.g.
• carboxylates of ethylenically unsaturated C 3 - to C 6 -mono- and dicarboxylic acid with monohydric C 1 - to C 18 -alcohols such as, for example C 1 - to C 18 -(meth)acrylates, such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, isobutyl acrylate and tert-butyl acrylate, n-butyl methacrylate, isobutyl methacrylate and tert-butyl methacrylate, hexyl acrylate, hexyl methacrylate, ethylhexyl acrylate, ethylhexyl acrylate, ethylhe
• styrene, acrylates, methacrylates, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate and butadiene are preferably used.
• Individual preferred acrylates and methacrylates are methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, tert-butyl acrylate, ethylhexyl acrylate, lauryl acrylate and the corresponding esters of methacrylic acid.
• any desired mixtures of said monomers for example mixtures of styrene and (meth)acrylates, such as n-butyl acrylate and/or tert-butyl acrylate, styrene and ethylhexyl acrylate, styrene and acrylonitrile and (meth)acrylates, such as n-butyl acrylate and/or tert-butyl acrylate.
• Suitable monomers of group (iii) are ethylenically unsaturated C 3 - to C 6 -carboxylic acids, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, ethacrylic acid, crotonic acid, monoesters of ethylenically unsaturated dicarboxylic acids, such as monomethyl maleate, monomethyl fumarate, monoethyl maleate, monoethyl fumarate, monopropyl maleate, monopropyl fumarate, mono-n-butyl maleate and mono-n-butyl fumarate, and styrenecarboxylic acids and ethylenically unsaturated anhydrides, such as maleic anhydride and itaconic anhydride.
• C 3 - to C 6 -carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, ethacrylic acid
• monomers comprising sulfo and phosphonic acid groups such as 2-acrylamido-2-methylpropanesulfonic acid and vinylphosphonic acid, are suitable as monomers (iii).
• the monomers comprising acid groups can be used in the form of the free acid groups and in a form partly or completely neutralized with alkali metal bases, alkaline earth metal bases, ammonia and/or amines.
• acrylic acid and methacrylic acid or mixtures of acrylic acid and methacrylic acid in any desired ratio are used from this group of monomers.
• Nonionic, hydrophilic, ethylenically unsaturated monomers for example amides or substituted amides of ethylenically unsaturated mono- or dicarboxylic acids, such as, for example, acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-ethylacrylamide and N-ethylmethacrylamide, are used as monomers (iv), which are optionally used for modifying the properties of the prepolymer.
• the prepolymer is usually prepared by a solution polymerization method from the abovementioned monomers (i) to (iv). This prepolymer is then diluted in water to a concentration of, for example, from 2 to 25% by weight and then subjected to the second polymerization stage.
• the abovementioned monomers of group (ii) are subjected to an emulsion polymerization in the presence of the prepolymer.
• any desired mixtures of said monomers for example mixtures of styrene and (meth)acrylates, such as n-butyl acrylate and/or tert-butyl acrylate, styrene and ethylhexyl acrylate, styrene and acrylonitrile and (meth)acrylates, such as n-butyl acrylate and/or tert-butyl acrylate.
• Such monomer mixtures may also be polymerized in the presence of a generally degraded starch.
• finely divided, cationic or amphoteric, aqueous polymer dispersions and the preparation process thereof are to be found in the abovementioned literature, to which express reference is made at this point.
• the at least one aqueous dispersion of a polymer size (b) is used in the process according to the invention for reducing deposits in the dry section in the production of paper, for example in an amount of from 0.005 to 5.0% by weight, preferably from 0.01 to 1% by weight, particularly preferably from 0.05 to 0.5% by weight, based in each case on the solids content of the paper stock.
• the sequence of addition of the components (a) and (b) is arbitrary, it being possible to add the components individually or as a mixture to the fiber suspension.
• the water-soluble cationic polymer (a) is metered into the paper stock.
• the addition can be effected to the high-consistency stock (fiber concentration>15 g/l, e.g. in the range from 25 to 40 g/l up to 60 g/l) or preferably to the low-consistency stock (fiber concentration ⁇ 15 g/l, for example in the range from 5 to 12 g/l).
• the point of addition is preferably before the wires but may also be between a shearing stage and a screen or thereafter.
• the aqueous dispersion of a polymer size (b) is generally added to the paper stock only after the addition of the water-soluble cationic polymer (a) but can also be added simultaneously and also as a mixture with (a) to the paper stock. Furthermore, it is also possible first to add the aqueous dispersion of a polymer size (b), and the metering of the water-soluble cationic polymer (a) is then effected.
• the process chemicals usually used in papermaking are used in the customary amounts, for example retention aid, drainage aid, other dry strength agents, such as, for example, starch, pigments, fillers, optical brighteners, antifoams, biocides and paper dyes.
• the process according to the invention is suitable for reducing all types of impurities in the dry section, in particular of resin residues in the fiber suspension, assistants from the papermaking, adhesives, binders from the papercoating and binders from printing inks.
• impurities or stickies whose deposits in the dry section are substantially reduced by the process according to the invention, are described, for example, in U.S. Pat. No. 6,387,215 B1, column 2, from line 22 to column 3, line 26.
• the present invention also relates to the papers and board and cardboard produced by the process described above.
• Suitable fibers for the production of the pulps for papermaking are all qualities customary for this purpose, for example mechanical pulp, bleached and unbleached chemical pulp and paper stocks from all annual plants.
• Mechanical pulp includes, for example, groundwood pulp, thermomechanical pulp (TMP), chemo-thermomechanical pulp (CTMP), pressure groundwood, semichemical pulp, high-yield chemical pulp and refiner mechanical pulp (RMP).
• TMP thermomechanical pulp
• CMP chemo-thermomechanical pulp
• RMP refiner mechanical pulp
• sulfate, sulfite and soda pulps are suitable as chemical pulp.
• unbleached chemical pulp which is also referred to as unbleached kraft pulp
• Suitable annual plants for the production of paper stocks are, for example, rice, wheat, sugarcane and kenaf.
• the process according to the invention is suitable in particular for the production of papers from wastepaper (comprising deinked wastepaper), which is used either alone or as a mixture with other fibers. It is also possible to start from fiber mixtures comprising a primary stock and recycled coated broke, for example bleached pine sulfate as a mixture with recycled coated broke.
• the process according to the invention is of industrial interest for the production of paper, board and cardboard from wastepaper and in specific cases also from deinked wastepaper, because it substantially increases the runnability of the paper machines through a reduction of deposits and consequently fewer tears.
• the pH of the stock suspension is, for example, in the range from 4.5 to 8, in general from 6 to 7.5.
• an acid such as sulfuric acid, or aluminum sulfate can be used for adjusting the pH.
• Cationic polyethyleneimine molecular weight about 1 200 000 dalton (Catiofast® SF from BASF SE)
• Cationic polyamine epichlorohydrin-dimethylamine condensate
• molecular weight about 100 000 dalton (Catiofast® 8154 from BASF SE)
• Cationic polydiallyldimethylammonium chloride molecular weight about 100 000 dalton (Catiofast® CS from BASF SE)
• Cationic polyacrylamide molecular weight about 8 000 000 dalton (Catiofast® 8356 from BASF SE)
• a mixture of 50% of newsprint and 50% of label printing paper was disintegrated until speck-free with tapwater at a consistency of 4% in a laboratory pulper at 40° C. for 25 min and then diluted with water to a solids content of 0.5%.
• % reduction of the deposits (deposition on a sample ⁇ deposition on an untreated sample)/deposition on an untreated sample [in each case in g]

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• 2010
  • 2010-06-11 WO PCT/EP2010/058193 patent/WO2010145990A1/de active Application Filing
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