Classifications

• • 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
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/04—Addition to the pulp; After-treatment of added substances in the pulp
  • D21H23/06—Controlling the addition
  • D21H23/14—Controlling the addition by selecting point of addition or time of contact between components
• • 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
  • D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
  • D21H17/24—Polysaccharides
  • D21H17/28—Starch
  • D21H17/29—Starch cationic
• • 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
  • D21H17/37—Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
  • D21H17/375—Poly(meth)acrylamide
• • 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
  • D21H17/41—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups
  • D21H17/44—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups cationic
  • D21H17/45—Nitrogen-containing groups
  • D21H17/455—Nitrogen-containing groups comprising tertiary amine or being at least partially quaternised
• • 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
  • D21H17/56—Polyamines; Polyimines; Polyester-imides
• • 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
  • D21H17/63—Inorganic compounds
  • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
  • D21H17/68—Water-insoluble compounds, e.g. fillers, pigments siliceous, e.g. clays

Definitions

• the invention relates to a method for producing paper and cardboard by dewatering pulps, with leaf formation and Drying the leaves with the pulps one after the other using two different ones water-soluble, cationic polymers added, then subject to at least one shear step and then through Add flocculated bentonite, colloidal silica or clay become.
• the method described at the outset is from EP-A-0 335 575 known.
• the pulp is first made with a low molecular weight, water soluble, cationic polymers and then with a high molecular, water-soluble cationic Polymers added.
• the low molecular weight water soluble cationic polymers have a molecular weight below 500,000.
• Suitable low molecular weight cationic polymers are, for example, polyethyleneimines, polyamines, polycyanediamide, Formaldehyde condensates and polymers of diallyldimethylammonium chloride, Dialkylaminoalkyl (meth) acrylates and dialkylaminoalkyl (meth) acrylamides.
• cationic polymers have molecular weights greater than 500,000. These are the usual polymers high molecular retention agents used in papermaking like cationic polyacrylamides.
• the flocculent fiber suspension becomes the cationic polymer subject to a shear step, e.g. in a pulper, refiner, Sieve or sifter, the so-called contained in the paper stock hard giant flakes are destroyed. Then you give bentonite, Colloidal silica or clay too, causing the destroyed flake components collected adsorptively to a "soft" microflake become. Then the pulp is drained under Leaf formation on a sieve and drying of the leaves.
• EP-A-0 235 893 describes a process for the production of paper and cardboard known, with an aqueous fiber suspension initially an essentially linear synthetic cationic polymer with a molecular weight of more than 500,000 in an amount of more than 0.03% by weight, based on the dry weight the suspension, then admixes the mixture in a shear field shears to form microflakes, then 0.03 to 0.5% by weight of bentonite was metered in and the pulp thus obtained was dewatered.
• the invention has for its object the drainage rate and thus the production speed at Increase paper production still further.
• suitable polymers of group a) are polyethyleneimines with a molecular weight M w of more than 500,000, preferably more than 700,000.
• the polymers can be used in the form of the free bases or as salts with organic or inorganic acids in papermaking.
• Polyethyleneimines of such a high molecular weight are prepared by known processes by polymerizing ethyleneimine in aqueous solution in the presence of acidic catalysts. Products of this type are commercially available. They usually have a broad molar mass distribution.
• Those polyethyleneimines which can be obtained as retentate by ultrafiltration of the polyethyleneimines in question are particularly effective. In ultrafiltration on membranes with exclusion limits of at least 500,000, for example 5 to 40% by weight of the polyethyleneimine used is separated off as permeate.
• Suitable polymers of group a) are vinylamine unit-containing polymers having a molecular weight M w of 5000 to 3 million polymers of this type can be obtained by polymerizing N-vinylformamide, if appropriate in the presence of other monomers copolymerizable therewith, and then partially or completely hydrolyzing the polymers by splitting off the formyl group from the polymerized vinylformamide units to form vinylamine units.
• Partially hydrolyzed homopolymers of N-vinylformamide are known, for example, from EP-B-0 071 050.
• the partially hydrolyzed homopolymers of N-vinylformamide described therein contain vinylamine and N-vinylformamide units in copolymerized form.
• those polymers are suitable in which the degree of hydrolysis is up to 100%.
• suitable polymers of component a) containing vinylamine units are the hydrolyzed copolymers of N-vinylformamide known from EP-B-0 216 387. They are obtainable by, for example, copolymerizing N-vinylformamide with other monoethylenically unsaturated monomers and then partially or completely hydrolyzing the copolymers. The hydrolysis takes place in the presence of acids, bases or also enzymatically. The polymerized N-vinylformamide units form vinylamine units during the hydrolysis by splitting off formyl groups.
• Suitable comonomers are, for example, vinyl formate, vinyl acetate, vinyl propionate, C 1 - to C 6 -alkyl vinyl ether, monoethylenically unsaturated C 3 - to C 8 -carboxylic acids, their esters, nitriles, amides and, if available, also the anhydrides, N-vinyl urea, N-vinyl imidazoles and N-vinylimidazolines.
• copolymers contain copolymerized carboxylic acids
• amphoteric copolymers are formed after the hydrolysis of the N-vinylformamide groups, the content of vinylamine units of which is greater than that of copolymerized units of ethylenically unsaturated carboxylic acids, so that these copolymers carry a cationic excess charge.
• ethylenically unsaturated carboxylic acids are acrylic acid, Methacrylic acid, dimethylacrylic acid, ethacrylic acid, crotonic acid, Vinyl acetic acid, allylacetic acid, maleic acid, fumaric acid, Citraconic acid and itaconic acid and their respective esters, Anhydrides, amides and nitriles.
• Anhydrides used with preference are, for example, maleic anhydride, citraconic anhydride and itaconic anhydride.
• Suitable as comonomers for the copolymerization with N-vinylformamide themselves esters which are preferably from alcohols with 1 to Derive 6 carbon atoms such as methyl acrylate, methyl methacrylate, ethyl acrylate, Ethyl methacrylate, isobutyl acrylate, hexyl acrylate or Glycols or polyalkylene glycols, each with only one OH group of glycols or polyglycols with a monoethylenic unsaturated carboxylic acid is esterified, e.g.
• Esters are also ethylenically suitable as comonomers unsaturated carboxylic acids with amino alcohols, e.g. Dimethylaminoethyl acrylate, Dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, Diethylaminoethyl methacrylate, dimethylaminopropyl acrylate and dimethylaminopropyl methacrylate.
• amides Acrylamide and methacrylamide into consideration.
• the basic ones Acrylates can be in the form of free bases, the salts with mineral acids or carboxylic acids or also in quaternary form in the Copolymerization with N-vinylformamide can be used.
• comonomers acrylonitrile, methacrylonitrile, N-vinylimidazole and substituted N-vinylimidazoles such as N-vinyl-2-methylimidazole and N-vinyl-2-ethylimidazole, N-vinylimidazoline and substituted N-vinylimidazolines such as N-vinyl-2-methylimidazoline.
• sulfo groups as comonomers Monomers such as vinyl sulfonic acid, allylsulfonic acid, styrene sulfonic acid and 3-sulfopropyl acrylic acid as others monoethylenic unsaturated monomers.
• the acid groups Containing monomers can be in the form of the free acids or as alkali or ammonium salts in the copolymerization with N-vinylformamide be used.
• regulators are, for example, sulfur in bound form containing organic compounds.
• Suitable regulators include, for example Mercapto compounds such as mercaptoethanol, mercaptopropanol, Mercaptobutanol, mercaptoacetic acid, mercaptopropionic acid, butyl mercaptan and dodecyl mercaptan.
• Allyl compounds such as allyl alcohol, aldehydes such as formaldehyde, Acetaldehyde, propionaldehyde, n-butyraldehyde and isobutyraldehyde, Formic acid, ammonium formate, propionic acid, hydrazine sulfate and Butenols. If the polymerization is in the presence of regulators is carried out, preferably 0.05 to 20% by weight is used, based on the monomers used in the polymerization.
• the monomers are usually polymerized in one Inert gas atmosphere in the absence of atmospheric oxygen. While The polymerization is generally good for thorough mixing the reactant concerned. With smaller approaches, where a safe dissipation of the heat of polymerization is guaranteed , the monomers can be copolymerized discontinuously, by bringing the reaction mixture to the polymerization temperature heated and then the reaction proceeds. This For example, temperatures are in the range of 40 to 180 ° C, under normal pressure, reduced or increased Pressure can be worked. Polymers with a high molecular weight is obtained by polymerizing in water carries out. This can be more water-soluble, for example Polymers in aqueous solution, as a water-in-oil emulsion or by the reverse suspension polymerization method respectively.
• N-vinylformamide To hydrolysis of N-vinylformamide during to avoid polymerization in aqueous solution, one carries out the Polymerization preferably in a pH range from 4 to 9, especially 5 to 8 through. In many cases it is advisable additionally work in the presence of buffers, e.g. primary or secondary sodium phosphate is used as a buffer.
• buffers e.g. primary or secondary sodium phosphate is used as a buffer.
• the homo- and copolymers of N-vinylformamide are subjected to hydrolysis with acids, bases or enzymes in a polymer-analogous reaction.
• Suitable acids are, for example, mineral acids such as hydrogen halide (gaseous or in aqueous solution), sulfuric acid, nitric acid, phosphoric acid and organic acids such as C 1 - to C 5 -carboxylic acids, e.g. B. formic acid, acetic acid and propionic acid or the aliphatic or aromatic sulfonic acids such as methanesulfonic acid, benzenesulfonic acid or toluenesulfonic acid.
• Hydrochloric acid or sulfuric acid is preferably used for the hydrolysis.
• the pH is 0 to 5.
• Per formyl group equivalent in the polymer for example, 0.05 to 1.5 equivalents of an acid, preferably 0.4 to 1.2, are required.
• metal hydroxides of metals can be used the first and second main group of the periodic table are, for example, lithium hydroxide, sodium hydroxide, Potassium hydroxide, magnesium hydroxide, calcium hydroxide, Strontium hydroxide and barium hydroxide. But also ammonia and alkyl derivatives of ammonia, e.g. Alkyl or aryl amines such as triethylamine, monoethanolamine, Diethanolamine, triethanolamine, morpholine or aniline.
• the pH is 8 to 14.
• the bases can in solid, liquid or possibly also in gaseous state diluted or undiluted.
• bases for the hydrolysis ammonia sodium hydroxide solution or potash lye.
• Hydrolysis in the alkaline and in the acidic pH range usually takes place at temperatures of, for example, 30 to 170, preferably 50 to 120 ° C. It is preferred after about 2 to 8 3 to 5 hours ended. After hydrolysis it will Reaction mixture preferably neutralized so that the pH the hydrolyzed polymer solution 2 to 8, preferably 3 to 7 is. Neutralization is particularly necessary if if the progress of hydrolysis is avoided or delayed shall be.
• copolymers of N-vinylformamide In the hydrolysis of copolymers of N-vinylformamide occurs optionally a further modification of the polymers thereby a that the copolymerized comonomers also be hydrolyzed.
• the copolymerized comonomers For example, from polymerized Units of vinyl esters of vinyl alcohol units. Dependent on from the hydrolysis conditions the polymerized ones can Vinyl esters may be fully or partially hydrolyzed.
• Polymerized during partial hydrolysis of vinyl acetate units contains copolymers of N-vinylformamide the hydrolyzed copolymer in addition to unchanged vinyl acetate units Vinyl alcohol units and vinylamine and N-vinylformamide units. From units of monoethylenically unsaturated Carboxylic acid anhydrides are formed during the hydrolysis of carboxylic acid units.
• Polymerized monoethylenically unsaturated Carboxylic acids are not chemically changed during hydrolysis. In contrast, ester and amide units saponify to carboxylic acid units. From polymerized monoethylenically unsaturated Nitriles form units of amides or carboxylic acids. Out Polymerized N-vinylurea can also be vinylamine units be formed. The degree of hydrolysis of the polymerized Comonomers can easily be determined analytically.
• the polymers containing vinylamine units have a molar mass M w of from 5000 to 3 million, preferably from 20,000 to 2 million.
• the partially or completely hydrolyzed polymers of N-vinylformamide have a charge density of 4 to 18, preferably 8 to 18 meq / g (determined at pH 7).
• the polymers of group a) are used in amounts of 0.01 to 0.8% by weight, preferably 0.01 to 0.5% by weight, in the process according to the invention.
• Polymers of group b) are, for example, cationic polyacrylamides with molecular weights M w of at least 4 million polymers of this type are described in EP-A-335 575 cited in the prior art. They are commercially available.
• the high molecular weight cationic polyacrylamides are produced by polymerizing acrylamide with cationic monomers.
• Suitable cationic monomers are, for example, the esters of ethylenically unsaturated C 3 to C 5 carboxylic acids with amino alcohols, such as dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and di-n-propylaminoethyl acrylate.
• Other suitable cationic monomers that can be copolymerized with acrylamide are N-vinylimidazole, N-vinylimidazoline and basic acrylamides such as dimethylaminoethylacrylamide.
• the basic monomers can be used in the form of the free bases, as salts or in quaternized form in the copolymerization.
• the cationic polyacrylamides contain, for example, 5 to 40, preferably 10 to 40, cationic monomers in copolymerized form.
• the molecular weights M w of the cationic polyacrylamides are at least 4,000,000 and in most cases are above 5,000,000, for example in the range from 5,000,000 to 1,500,000.
• Suitable cationic polymers of group b) are vinylamine units containing polymers, the molecular weights of at least Have 4000000. Polymers containing vinylamine units have already been described above. The here as component b) in Polymers containing vinylamine units are considered differ from those of group a) in that they have a have a higher molecular weight. These polymers are preferably completely or partially hydrolyzed homopolymers of the N-vinylformamide. Hydrolyzed are also suitable Copolymers of N-vinylformamide with vinyl formate, vinyl acetate, Vinyl propionate, acrylic acid, methacrylic acid, N-vinyl pyrrolidone and N-vinylcaprolactam.
• Copolymers of N-vinylformamide and ethylenically unsaturated carboxylic acids are after hydrolysis amphoteric, but always have an excess of cationic Charge on.
• the polymers preferably contain up to copolymerized at most 40 wt .-% vinylamine units. Especially such polymers are preferably used that 10 to Contain 35 wt .-% vinylamine units.
• the vinylamine units Group b) containing polymers preferably have one Charge density at pH 7 of, for example, 0.5 to 7 milliequivalents per gram. You will get the pulp in quantities of 0.005 to 0.5, preferably 0.01 to 0.2 wt .-% added.
• all paper qualities can and cardboard, for example paper for newspaper printing, so-called medium-fine writing and Printing papers, gravure papers and also lightweight ones Coating base papers.
• One can, for example, ground wood, thermomechanical Fabric (TMP), chemo-thermomechanical fabric (CTMP), Use pressure grinding (PGW) as well as sulfite and sulfate pulp.
• Pulp also comes as raw materials for the production of the pulp and wood pulp into consideration. These substances are mainly used in the so-called integrated factories in more or less humid Form directly without further thickening or drying Paper processed. Because of the not completely removed from it These fiber materials still contain impurities Fabrics that severely disrupt the usual paper manufacturing process. To However, the method according to the invention can also contain contaminants containing pulps can be processed easily.
• both filler-free as well as filler-containing paper can be up to a maximum of 40% by weight and is preferably in the range of 5 to 25% by weight.
• Suitable Fillers are, for example, clay, kaolin, native and precipitated Chalk, titanium dioxide, talc, calcium sulfate, barium sulfate, Alumina, satin white or mixtures of the above Fillers.
• the consistency of the pulp is, for example, 0.1 to 15% by weight.
• At least one cationic polymer from group a) is first added to the fiber slurry and then at least one cationic polymer from group b) is added. This addition causes a strong flocculation of the paper stock.
• the z. B. in one or more cleaning, mixing and pumping stages or a pulper, classifier or also in a refiner or sieve through which the pre-flocked paper stock is passed, the so-called "hard giant flakes" present in the flocked system are destroyed .
• bentonite, colloidal silica or clay are added, which forms what are known as soft microflakes.
• bentonite colloidal silica or clay
• the amounts of bentonite, colloidal silica or clay are 0.01 to 2, preferably 0.05 to 0.5% by weight, based on dry paper stock.
• Bentonite is a layered aluminum silicate based on montmorillonite that occurs naturally. It is mostly used after the calcium ions have been replaced by sodium ions.
• bentonite in an aqueous slurry is treated with sodium hydroxide solution. This makes it fully swellable in water and forms highly viscous tixotropic gel structures.
• the platelet diameter of the bentonite is, for example, 1 to 2 ⁇ m, the platelet thickness is approximately 1 nm (10 ⁇ ).
• the bentonite has a specific surface area of 60 to 800 m 2 / g. Due to the large inner surface and the outwardly negative excess charges on the surface, such inorganic polyanions can be used for adsorptive collection effects of cationically charged and sheared paper materials. This results in optimal flocculation in the paper stock.
• the cationic monomers of groups a) and b) used according to the invention surprisingly, compared to the prior art, there is a further improvement in the dewatering rate of paper materials, in particular of paper materials which contain contaminants, such as humic acids, wood extract or lignin sulfonates.
• the percentages in the examples mean percent by weight, unless the context indicates otherwise.
• the molecular weights M w were determined using the static light scattering method. Paper sheets are produced in a Rapid Köthen sheet former. The optical permeability of the white water was checked with a Dr. Long spectrometer determined at 588 nm. The drainage times, which are given in the examples, were determined for 500 ml of filtrate in the Schopper-Riegler test device.
• a pulp was made from 100 parts of printed newsprint a consistency of 6 g / l and a freeness of 50 ° SR.
• the pH of the pulp was 7.6.
• the pulp was divided into several Split samples. In the examples according to the invention first the cationic polymer of type a) and then the cationic Polymer dosed according to b). The pulps were then each 1 min with a stirrer at a speed of 1500 revolutions / min touched. Then 0.2% bentonite, based on dry paper stock and determined the drainage time in a Schopper-Riegler test device. The optical permeability the white water was also determined.

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• Paper (AREA)
• Machines For Manufacturing Corrugated Board In Mechanical Paper-Making Processes (AREA)
• Separation Of Suspended Particles By Flocculating Agents (AREA)

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• 1996
  • 1996-07-09 DE DE19627553A patent/DE19627553A1/de not_active Withdrawn
• 1997
  • 1997-07-07 EP EP97930506A patent/EP0910701B1/de not_active Expired - Lifetime
  • 1997-07-07 JP JP10504781A patent/JP2000514144A/ja not_active Withdrawn
  • 1997-07-07 ES ES97930506T patent/ES2151736T3/es not_active Expired - Lifetime
  • 1997-07-07 CA CA002258569A patent/CA2258569C/en not_active Expired - Fee Related
  • 1997-07-07 WO PCT/EP1997/003574 patent/WO1998001623A1/de active IP Right Grant
  • 1997-07-07 US US09/147,486 patent/US6132558A/en not_active Expired - Lifetime
  • 1997-07-07 DE DE59702462T patent/DE59702462D1/de not_active Expired - Lifetime
  • 1997-07-07 AT AT97930506T patent/ATE196937T1/de active
• 1999
  • 1999-01-08 NO NO990078A patent/NO990078D0/no not_active Application Discontinuation

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