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
  • 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

Definitions

• US Pat. No. 4,421,602 discloses hydrolyzed homopolymers of N-vinylformamide which contain 90 to 10 mol% of vinylamine units and 10 to 90 mol% of N-vinylformamide units.
• the hydrolyzed polyvinylformamides are used as retention and drainage agents in the manufacture of paper. Because of the vinylamine units, the polymers have a positive charge in aqueous solution. They are therefore adsorbed by the negatively charged surfaces of the solid particles in the paper stock and thus facilitate the binding of the originally negatively charged particles to one another. As a result, an increased drainage rate and improved retention are observed.
• the effectiveness of the cationic products is known to be significantly adversely affected by the presence of contaminants in the paper stock. Interfering substances are understood to mean oligomeric or polymeric substances with an anionic charge character, which worsen the drainage rate and the retention in the manufacture of paper. Such contaminants accumulate increasingly in the water cycles of paper machines because the used water is recycled to an increasing extent.
• EP-A 0 249 891 discloses a process for the production of paper, cardboard and cardboard, in which paper materials containing impurities are dewatered in the presence of nonionic polymers, such as homopolymers of N-vinylformamide or of N-vinylpyrrolidone.
• nonionic polymers such as homopolymers of N-vinylformamide or of N-vinylpyrrolidone.
• the polymers mentioned act as retention aids and drainage aids.
• Their effectiveness is considerably increased if non-ionic condensation products, e.g. Condensation products of phenol and formaldehyde of the resol and novolak type are present.
• the present invention has for its object to provide dewatering, retention and flocculants for the papermaking process, which have a better activity in paper containing impurities than the polymers described above.
• a paper stock containing interfering substances is dewatered, for the production of which all fiber qualities are considered either alone or as a mixture with one another.
• Inorganic fillers such as clay, chalk, gypsum or titanium dioxide and mixtures of these fillers can be added to the fibrous materials in customary amounts.
• water is used for the production of the paper stock, which is at least partially or completely returned from the paper machine. These are clarified or untreated white water and mixtures of such water qualities.
• the returned water contains more or less large amounts of so-called contaminants, which - as mentioned - severely impair the effectiveness of the previously used cationic retention and drainage aids.
• Such effects are described for example in the technical literature, cf.
• the content of such contaminants in the paper stock can be characterized, for example, with the sum parameter "Chemical oxygen demand” (COD value).
• COD value the sum parameter
• this sum parameter also includes nonionic or low molecular weight substances which do not directly interfere with drainage or retention, but which, for example, always occur as a by-product of constituents of wood as accompanying substances of contaminants.
• the COD values of the interfering paper materials to be dewatered according to the invention are 300 to 30,000, preferably 1,000 to 20,000 mg oxygen / kg of the aqueous phase of the interfering paper material.
• Fibers for the production of pulps that contain contaminants are, for example, wood pulp, unbleached pulp, waste paper pulp and paper pulp from all annual plants.
• wood pulps include wood pulp, thermomechanical material (TMP), chemo-thermomechanical material (CTMP), pressure grinding, semi-pulp, high-yield pulp and refiner mechanical pulp (RMP).
• TMP thermomechanical material
• CMP chemo-thermomechanical material
• RMP refiner mechanical pulp
• unbleached pulp the unbleached kraft pulp is particularly suitable, but also the unbleached sulfite pulp.
• waste paper all qualities are suitable, both sorted and unsorted. Are particularly suitable deinked waste paper.
• Usable annual plants for the production of paper materials are, for example, rice, wheat, sugar cane and kenaf.
• the following compounds are to be regarded as interfering substances: sodium silicate, which comes from deinking and the peroxide bleaching of waste paper materials, polyphosphates and polyacrylates from filler dispersions that are used in paper manufacture, humic acids from raw water, carboxymethyl cellulose from waste paper or coated scrap, anionic starches from waste paper or deleted committee, lignin derivatives from sulfate pulp, wood pulp, TMP or CTMP substances, hemicelluloses and their degradation products from wood pulp, TMP or CTMP substances and lignin sulfonates from unbleached sulfite pulps.
• sodium silicate which comes from deinking and the peroxide bleaching of waste paper materials
• polyphosphates and polyacrylates from filler dispersions that are used in paper manufacture humic acids from raw water, carboxymethyl cellulose from waste paper or coated scrap, anionic starches from waste paper or deleted committee
• lignin derivatives from sulfate pulp, wood pulp, TMP or CTMP substances
• the polymers which contain the units of the formulas I and II have K values of at least 130 (determined according to H. Fikentscher in 5% strength by weight saline solution at 25 ° C. and a polymer concentration of 0.1% by weight).
• the polymers are obtainable by homopolymerization or copolymerization of N-vinylamides of the formula
• R1 and R2 have the meaning given in the formulas I and II.
• Compounds of the formula III are, for example, N-vinylformamide, N-vinyl acetamide, N-ethyl-N-vinyl formamide, N-ethyl-N-vinyl acetamide, N-methyl-N-vinyl formamide, N-methyl-N-vinyl acetamide and N-vinyl propionamide.
• the homo- and copolymerization of the N-vinylamides of the formula III leads to homo- or copolymers which contain units of the formula I in copolymerized form.
• the homopolymers and copolymers of the vinylamides of the formula III are subjected to hydrolysis in the presence of acids or bases at temperatures up to 170 ° C., for example in the Range from 20 to 170 ° C, preferably 50 to 120 ° C.
• the degree of hydrolysis of the polymerized units of the formula I is essentially dependent on the concentration of the amounts of acid or base used and the temperature.
• Mineral acids such as hydrogen halide, sulfuric acid, nitric acid and phosphoric acid, and organic acids, for example, are suitable for the hydrolysis of the copolymers.
• Acetic acid, propionic acid, benzenesulfonic acid and alkylsulfonic acids such as dodecylsulfonic acid.
• bases can also be used for the hydrolysis, for example metal hydroxides of metals of the 1st and 2nd main group of the Periodic Table of the Elements, for example lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide.
• Ammonia and derivatives of ammonia can also be used as bases, for example triethylamine, monomethanolamine, diethanolamine, triethanolamine and morpholine.
• the hydrolysis of the homo- and copolymers of the N-vinylamides of the formula III is carried out to such an extent that less than 10, preferably 1 to 9 mol% of the units of the formula I contained in the polymers are converted into units of the formula II.
• copolymers are also suitable which contain up to 50% by weight, preferably up to 30 Wt .-%, at least one other ethylenically unsaturated monomer copolymerized.
• Suitable comonomers for the N-vinylamides of the formula III are, for example, vinyl acetate, vinyl propionate, C1- to C4-alkyl vinyl ether, N-vinylpyrrolidone, and also esters, nitriles and amides of ethylenically unsaturated C3- to C8-carboxylic acids, in particular esters, nitriles and amides of acrylic acid or methacrylic acid. Processes for the preparation of the hydrolyzed homopolymers and copolymers of compounds of the formula III are known.
• the hydrolyzed polymers can be present as an aqueous solution, as a water-in-oil polymer emulsion, as a powder or as a bead polymer.
• Bead polymers are prepared, for example, by the known reverse suspension polymerization process.
• the above-described homopolymers and copolymers containing less than 10 mol% of vinylamine units of the formula II are, according to the invention, a paper material containing impurities as dewatering, retention and flocculating agents in amounts of 0.002 to 0.1, preferably 0.005 to 0.05,% by weight. -%, based on dry paper stock added.
• the Polymers to be used according to the invention are added to the paper stock in a very dilute aqueous solution, as is customary when using other high-molecular water-soluble polymers.
• concentration in the aqueous solution is generally between 0.01 and 0.1% by weight.
• the main advantages of the process according to the invention are the low sensitivity of the polymers containing less than 10 mol% of units of the formula II to the presence of interfering substances and the fact that that no additional fixative for the high molecular weight polymer, as described in EP-A 0 249 891, has to be used.
• the parts given in the examples are parts by weight. The percentages relate to the weight of the fabrics.
• 1 liter of the pulp suspension to be tested is dewatered in a Schopper-Riegler test device.
• the time that is determined for different outlet volumes is evaluated as a criterion for the drainage rate of the substance suspension examined in each case.
• the drainage times were determined after a run of 500 or 600 ml of water.
• the charge density of the hydrolyzed polymers based on poly-N-vinylformamide was determined with the aid of an enzymatic ant determination method (company publication "Methods of Enzymatic Food Analysis” by Boehringer Mannheim GmbH, 1984).
• Polymer 4 homopolymer of N-vinylformamide with a K value of 218.
• Polymer 5 Hydrolyzed poly-N-vinylformamide, which contained 89.9 mol% of N-vinylformamide units and 10.1 mol% of vinylamine units and had a K value of 218.
• a pulp with a consistency of 4 g / l was produced from 100% mixed waste paper.
• the pH in the stock suspension was 8.1.
• 4% water glass, based on dry paper stock was added to the paper stock.
• Samples of this paper stock were each dewatered in the presence of the polymers shown in Table 1.
• the polymers were used in an amount of 0.04%, based on dry paper stock.
• the drainage times for 600 ml of filtrate in the Schopper-Riegler test device and the optical transmittance of the filtrate obtained are given in Table 1.
• Comparative Example 3 the paper stock described above was dewatered without any further addition.
• a pulp with a consistency of 4 g / l was produced from 80 parts of TMP material, 20 parts of bleached sulfate pulp and 30 parts of kaolin as filler.
• the pH was adjusted to 6.0 by adding alum.
• 50 ml of an aqueous TMP extract from an industrial-scale TMP production were added per liter.
• the polymers specified in Table 2 were added to samples of this paper stock in an amount of 0.02% polymer, based on dry paper stock, and the drainage time for 500 ml of filtrate in the Schopper-Riegler test device and the optical transmission were determined. The following results were obtained:
• a pulp was made from 100% unbleached sulfate pulp with a consistency of 5 g / l.
• the pH was 7.9.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Paper (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Making Paper Articles (AREA)
• Machines For Manufacturing Corrugated Board In Mechanical Paper-Making Processes (AREA)
• Medicines Containing Antibodies Or Antigens For Use As Internal Diagnostic Agents (AREA)

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• 1990
  • 1990-01-25 DE DE4002065A patent/DE4002065A1/de not_active Withdrawn
  • 1990-12-21 AT AT90125089T patent/ATE103023T1/de not_active IP Right Cessation
  • 1990-12-21 DE DE90125089T patent/DE59005019D1/de not_active Expired - Lifetime
  • 1990-12-21 ES ES90125089T patent/ES2050350T3/es not_active Expired - Lifetime
  • 1990-12-21 DK DK90125089.4T patent/DK0438755T3/da active
  • 1990-12-21 EP EP90125089A patent/EP0438755B1/fr not_active Expired - Lifetime
• 1991
  • 1991-01-09 US US07/639,097 patent/US5098521A/en not_active Expired - Lifetime
  • 1991-01-22 FI FI910328A patent/FI102688B1/fi active IP Right Grant
  • 1991-01-23 JP JP3006194A patent/JP2921609B2/ja not_active Expired - Lifetime
  • 1991-01-24 CA CA002034869A patent/CA2034869C/fr not_active Expired - Lifetime
  • 1991-01-24 NO NO910283A patent/NO176526C/no not_active IP Right Cessation

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