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 the use of partially hydrolyzed homopolymers of N-vinylformamide as retention aids, drainage aids and flocculants in the manufacture of paper.
• anionic compounds accumulate in the returned water, which severely impair the effectiveness of cationic polymeric process chemicals in the dewatering of paper stock and the retention of fillers and fibers.
• the procedure in practice is to additionally dewater these paper materials in the presence of a fixing agent.
• condensates made from dicyandiamide and formaldehyde or condensates made from dimethylamine and epichlorohydrin are used as fixatives, cf. Tappi Journal, August 1988, pages 131 to 134.
• the object of the present invention is to provide products which are more effective than the previously used fixing agents and which, in combination with cationic retention agents, have an improved retention, flocculation and drainage effect than combinations previously used.
• the object is achieved according to the invention with a process for the production of paper, cardboard and cardboard by dewatering a paper material containing impurities in the presence of fixing agents and cationic retention agents if the fixing agent is hydrolyzed homo- and / or copolymers of N-vinylformamide with a degree of hydrolysis of at least Uses 60%.
• paper materials are dewatered, for their production all fiber qualities, either alone or in Mixture among themselves.
• water is used for the production of the paper stock, which is at least partially or completely returned from the paper machine. These are either clarified or unclarified white water and mixtures of such water qualities.
• the returned water contains more or less large amounts of so-called contaminants, which are known to have a very severe effect on the effectiveness of the cationic retention and drainage agents.
• the content of such contaminants in the paper stock can be characterized, for example, with the sum parameter chemical oxygen demand (COD value).
• the COD values of such paper stock are 300-30,000, preferably 1,000-20,000 mg oxygen / kg of the aqueous phase of the paper stock.
• wood pulp includes 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
• suitable pulps are sulfate, sulfite and sodium pulps.
• the unbleached pulps which are also referred to as unbleached kraft pulp, are preferably used.
• Suitable annual plants for the production of paper materials are, for example, rice, wheat, sugar cane and kenaf. Waste paper is also used to produce the pulps, either alone or in a mixture with other fibrous materials.
• Pulps of the type described above contain more or less large amounts of interfering substances which, as already explained above, can be determined using the COD value or also using the so-called cationic requirement.
• the cationic requirement is the amount of a cationic polymer that is necessary to bring a defined amount of white water to the isoelectric point. Since the cationic requirement is very much dependent on the composition of the cationic retention agent used for the determination, a polyamidoamine obtained from example 3 of DE-PS 2 434 816 from adipic acid and diethylenetriamine was used for the standardization, which was grafted with ethyleneimine and crosslinked with polyethylene glycol dichlorohydrin ether was, cf. the polymer I described below.
• the pulps containing impurities have the COD values given above and have a cationic requirement of more than 50 mg polymer I / l white water.
• the fixing agent for paper materials containing impurities is hydrolyzed homo- and / or copolymers of N-vinylformamide with a degree of hydrolysis of at least 60%.
• Polymers of this type are known, for example, from EP application 0 216 387.
• N-vinylformamide is polymerized and formyl groups are split off from the polymer by hydrolysis in the presence of acids or bases. The cleavage of the formyl group from the polymers containing N-vinylformamide units in copolymerized form leads to the formation of vinylamine units in the polymer.
• the degree of hydrolysis of the polymerized N-vinylformamide is at least 60, preferably 70-100 mol%.
• the cleavage of the formyl groups can, however, also be carried out with the exclusion of water with hydrogen chloride or hydrogen bromide.
• an N-formyl group of the copolymer forms an amino group with elimination of carbon monoxide.
• acids or bases act on copolymers of N-vinylformamide and acrylonitrile, methacrylonitrile, N-vinylpyrrolidone and C1- to C4-alkyl vinyl ethers, the comonomers of N-vinylformamide are hardly changed chemically, while the copolymerized N-vinylformamide is at least partially hydrolyzed.
• copolymers of N-vinylformamide with vinyl acetate and / or Vinyl propionate is obtained, for example, under the action of hydrochloric acid at a temperature of 50 ° C., in which the copolymerized vinyl acetate or vinyl propionate is not hydrolyzed, whereas the copolymerized N-vinylformamide is at least 60%.
• copolymers of N-vinylformamide and vinyl acetate or vinyl propionate are treated with sodium hydroxide solution at a temperature of 50 ° C.
• the formyl groups from the polymerized N-vinylformamide and the acetyl or propionyl groups from the polymerized vinyl acetate or vinyl propionate are approximately the same Split off the dimensions of the copolymer.
• the degree of hydrolysis of the polymers depends mainly on the amount of acid or base used and the temperature during the hydrolysis.
• the homo- and copolymers of N-vinylformamide with a degree of hydrolysis of at least 60% have K values according to Fikentscher (measured in 5% aqueous saline solution at a polymer concentration of 0.5% by weight and a temperature of 25 ° C) of 30-150, preferably 60-90.
• the fixing agents are used in customary amounts, ie of 0.02-2, preferably 0.05-0.5% by weight, based on dry paper stock.
• All commercially available products for this purpose can be used as cationic retention agents. These are, for example, polyethyleneimines, polyamines with a molecular weight of more than 50,000, polyamidoamines which may have been modified by grafting on ethyleneimine, polyetheramines, polyvinylimidazoles, polyvinylpyrrolidines, polyvinylimidazolines, polyvinyltetrahydropyridines, polydialkylaminoalkylvinylethers, polydialkylamate alkylated (acrylated) acrylated (acrylated) methacrylate (acrylated) methacrylate (methacrylate) acrylate (or methylated) acrylated (acrylated) methacrylate (methoxylated) acrylate (methoxylated) acrylate (methoxylated) acrylate (acrylated) methacrylate (methacrylate) formated .
• polyethyleneimines polyamines with a molecular weight of more than 50,000
• Suitable compounds are, for example, polydiallyldialkylammonium halides, in particular polydiallyldimethylammonium chloride.
• Particularly preferred retention aids are polyamidoamines from adipic acid and polyalkylene polyamines, such as diethylenetriamine, which are grafted with ethyleneimine and crosslinked with polyethylene glycol dichlorohydrin ethers according to the teaching of DE-PS 2 434 816 or with epichlorohydrin, and commercially available polyethyleneimines and copolymers of acrylamide or methamyl acrylate or methamyl acrylate and methamyl acrylate or methacrylamide and acrylamyl acrylate or methacrylamide and acrylamyl acrylate or methacrylamide and acrylamyl acrylate or methacrylamide and acrylamyl acrylate or methacrylamide and acrylamyl acrylate or methacrylamide and acrylamyl acrylate or methacrylamide and
• Basic acrylates are preferably in neutralized or quaterized form with acids.
• the quaternization can take place, for example, with methyl chloride or dimethyl sulfate.
• the cationic retention agents have K values according to Fikentscher (determined in 5% aqueous saline solution at a polymer concentration of 0.5% by weight and a temperature of 25 ° C) of at least 180.
• dehydration-containing paper materials are dewatered in the presence of hydrolyzed N-vinylformamide polymers as fixing agents and the commonly used cationic retention agents. It is preferable to add the fixing agent to the paper stock first and then the retention agent. However, they can also be added to the paper stock at the same time. It is only essential that the paper stock is dewatered in the presence of fixative and retention aid.
• the retention aids are used in an amount of 0.01 to 0.2% by weight, based on dry paper stock.
• the ratio of fixative to retention aid is generally 1: 2 to 5: 1. Compared to conventional combinations of fixatives and cationic retention aids, improved retention and accelerated dewatering of the paper stock are obtained by the process according to the invention.
• the chemical oxygen demand, COD value was determined according to DIN 38 409.
• the light transmission of the white water was measured with the Zeiss PM 7 spectrophotometer. It is a measure of the retention of fine and fillers. It is given in percent. The higher the value for the light transmittance, the better the retention.
• the end point was determined with the aid of polyelectrolyte titration according to D. Horn, Progr. Colloid & Polym. Sci. Vol. 65, 251-264 (1978).
• Polymer I polyamidoamine from adipic acid and diethylenetriamine, which was grafted with ethyleneimine and crosslinked with polyethylene glycol dichlorohydrin ether as described in Example 3 of DE-PS 2 434 816.
• Polymer II polyamidoamine from adipic acid and diethylenetriamine, which was grafted with ethyleneimine and crosslinked with epichlorohydrin.
• Polymer III Commercial high molecular weight polyethyleneimine which was adjusted to a pH of 7.5 with formic acid.
• Polymer IV copolymer of 70% acrylamide and 30% N-dimethylaminoethyl acrylate in the form of methochloride with a K value of 220.
• Polymer A Hydrolyzed homopolymer of N-vinylformamide with a degree of hydrolysis of 96% and a K value of 75.
• Polymer B Hydrolyzed copolymer 70% N-vinylformamide and 30% vinyl acetate, in which 96% of the formyl groups of the polymerized N-vinylformamide and 68% of the polymerized vinyl acetate groups had been hydrolyzed.
• the K value of the hydrolyzed copolymer was 75.
• Polymer C Commercial condensate of dicyandiamide and formaldehyde as a comparison with the prior art.
• Polymer D Commercial homopolymer of diallyldimethylammonium chloride with a K value of 100 as a comparison.
• the material model used was a wood and kaolin-containing newsprint with a density of 2 g / l with a pH of 7 and a degree of paint of 68 ° SR.
• the paper stock also contained 3% sodium lignin sulfonate as a contaminant.
• the amounts of fixing agent given in Table 2 and then 0.06% of polymer 1 as the cationic retention agent were added to samples of this paper stock.
• the dewatering time was first determined in a Schopper-Riegler test device and the light transmittance was determined on the filtrate obtained.
• sheets with a basis weight of 70 g / m2 were formed on the Rapid-Köthen device and their ash content was determined. The amounts used in each case and the results obtained therewith are given in Table 2.
• a paper stock with a consistency of 5 g / l from 75% wood pulp, 25% pine sulfate pulp, 35% china clay with a degree of grinding of 25 ° SR and a pH of 7 was turned into paper on a test paper machine at a machine speed of 80 m / minute processed with a basis weight of 60 g / m2.
• the paper stock contained 0.2% of the sodium salt of humic acid and 0.2% of polymer 1 as a retention agent. Under these conditions, the dewatering time was 124 seconds and the ash retention was 57.4%.
• the polymers described in Table 3 were added to the paper stock described above. The results obtained are given in Table 3.
• a wood and kaolin-containing newsprint with a consistency of 2 g / l and a pH value of 7 and a degree of paint of 68 ° SR was used as the model substance.
• 3% sodium lignin sulfonate was added as an interfering substance.
• the paper stock thus obtained was dewatered in a Schopper-Riegler device.
• the results obtained without the addition of a retention and drainage agent are shown in Table 4, as are the results obtained by adding 0.2% of the polymers mentioned in the table as a fixing agent and then adding 0.06% polymer 1 were obtained as a retention aid.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Paper (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Applications Claiming Priority (2)

Publications (2)

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• 1990
  • 1990-01-16 DE DE4001045A patent/DE4001045A1/de not_active Withdrawn
  • 1990-12-13 DE DE90124067T patent/DE59003890D1/de not_active Expired - Lifetime
  • 1990-12-13 ES ES199090124067T patent/ES2046658T3/es not_active Expired - Lifetime
  • 1990-12-13 EP EP90124067A patent/EP0438707B1/fr not_active Expired - Lifetime
• 1991
  • 1991-01-14 CA CA002034135A patent/CA2034135C/fr not_active Expired - Lifetime
  • 1991-01-14 JP JP3002606A patent/JP2895248B2/ja not_active Expired - Lifetime
  • 1991-01-15 FI FI910206A patent/FI102687B/fi active IP Right Grant
  • 1991-01-16 US US07/641,852 patent/US5145559A/en not_active Expired - Lifetime

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