US20050061461A1 - Production of paper board and cardboard - Google Patents

Production of paper board and cardboard Download PDF

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Publication number
US20050061461A1
US20050061461A1 US10/498,085 US49808504A US2005061461A1 US 20050061461 A1 US20050061461 A1 US 20050061461A1 US 49808504 A US49808504 A US 49808504A US 2005061461 A1 US2005061461 A1 US 2005061461A1
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Prior art keywords
weight
paper
cationic
optical brighteners
retention
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Friedrich Linhart
Thierry Blum
Ralf Hemel
Klaus Bohlmann
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BASF SE
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Assigned to BASF AKTIENGESELLSCHAFT reassignment BASF AKTIENGESELLSCHAFT ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BLUM, THIERRY, BOHLMANN, KLAUS, HEMEL, RALF, LINHART, FRIEDRICH
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    • 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
    • D21H17/71—Mixtures of material ; Pulp or paper comprising several different materials not incorporated by special processes
    • D21H17/72—Mixtures of material ; Pulp or paper comprising several different materials not incorporated by special processes of organic material
    • 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
    • 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
    • D21H17/47—Condensation polymers of aldehydes or ketones
    • 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
    • D21H21/30—Luminescent or fluorescent substances, e.g. for optical bleaching

Definitions

  • the present invention relates to a process for the production of paper and cardboard by draining a paper stock in the presence of at least one cationic polymer on a wire.
  • paper substantially comprises fibers, consisting of wood and/or of cellulose, and, if required, of mineral fillers, in particular calcium carbonate and/or aluminum silicate, and that the essential process in papermaking consists in separating these fibers and fillers from a dilute aqueous suspension of these substances with the aid of at least one wire. It is also known that certain chemicals are added to the suspension of fibers and fillers in water, both for improving the separation process and for achieving or improving certain properties of the paper. A very up-to-date overview of the paper chemicals which can be generally used and their use is to be found in— Paper Chemistry, J. C.
  • a retention aid Depending on their composition, they ensure, for example, that more fine material remains behind on the wire or that the water is separated off more rapidly on the wire or that certain substances are fixed on the paper fibers and hence do not enter the white water, it being possible for both cleanliness of the white water and the effect of the fixed substances, e.g. dyes or sizes, on the properties of the final paper product to be important in the case of the latter property.
  • polycations can also increase the strength of the paper or impart improved residual strength to the paper in the wet state. If the object of a cationic polyelectrolyte is to retain more fine material on the wire and to accelerate the removal of the water on the wire, it is referred to as a retention aid.
  • the term fixing agent is used. If the cationic polyelectrolyte improves a paper property relevant to strength, it is a strength agent.
  • a high level of whiteness not only imparts the impression of cleanliness and safety but also increases the legibility of the script as a result of the greater contrast to the ink, especially in poor illumination.
  • a particular advantage of the high level of whiteness is evident if the paper or cardboard is to be printed on, written on or painted in color. The whiter the surface, the better and more natural is the color contrast, particularly when writing on, printing on or painting with light or translucent colors or pastel shades.
  • the papermaker's product is substantially grayer than with the use of fresh fibers.
  • a known method for increasing the whiteness and brightness of paper is the use of optical brighteners, which, according to the prior art to date, is added to the paper pulp during various operations of papermaking and of paper conversion or is applied to the paper.
  • dye-like fluorescent compounds which absorb shortwave, ultraviolet light invisible to the human eye and emit it again as longer-wave blue light, with the result that the human eye perceives a higher level of whiteness and the degree of whiteness is thus increased.
  • optical brighteners used in the paper industry are generally 1,3,5-triazinyl derivatives of 4,4′-diaminostilbene-2,2′-disulfonic acid, which derivatives may carry additional sulfo groups, for example 2, 4 or 6 altogether.
  • An overview of such brighteners is to be found, for example, in: Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition, 2000 Electronic Release, OPTICAL BRIGHTENERS—Chemistry of Technical Products.
  • more recent brightener types are also suitable, for example derivatives of 4,4′-distyrylbiphenyl, as also described in the abovementioned Ullmann's Encyclopedia of Industrial Chemistry.
  • the optical brighteners can be used in various phases of papermaking and paper conversion.
  • the optical brighteners can be added, for example, to the paper pulp but also in a size press together with surface sizes or strength agents, e.g. starch, or together with further assistants.
  • optical brighteners are used in paper coating slips with which paper and cardboard are coated.
  • the use in the pulp is particularly advantageous when the uniformity of the brightening and good fastness to bleeding are important (cf. for example W. Bieber, A. Brockes, B. Hunke, J. Krüsemann, D. Loewe, F. Müller, P.
  • optical brighteners leads to optimum success only when they are present in the paper not only in an optimum distribution but also in optimum chemical structure and conformation, since, for example in the case of stilbenes, only the trans form is optically active and this exhibits maximum fluorescence only when it is distributed in monomolecular form and is fixed in a plane (see above, K. P. Kreutzer). When added to the paper pulp, this generally results through adsorption onto the cellulose.
  • the brighteners used are chemically modified so that they have a high affinity to cellulose and therefore require no additional fixing agents or brightener enhancers, i.e. carriers.
  • optical brighteners when used in the paper pulp, it is necessary to pay greater attention to ensuring that no further chemicals in the pulp reduce the effects of the brighteners (cf. literature above).
  • the presence of cationic polymers is considered to be particularly harmful to the action of optical brighteners.
  • they are generally considered as fluorescence extinguishers, cf. W. Bieber et al, Blankophor®—Optische Aufheller fur die Pandaindustrie, Bayer AG, SP600, 8.89, page 59.
  • EP-A-0 192 600 discloses stable solutions of optical brighteners. They contain from 10 to 500 parts by weight of a polyethylene glycol having an average molar mass of from 1 000 to 3 000 and at least 20% by weight, based on the total mixture, of water per 100 parts by weight of a brightener. The mixtures are used as optical brighteners in paper coating slips.
  • EP-A-0 071 050 discloses linear, basic polymers which contain 90-10 mol % of vinylamine units and 10-90 mol % of N-vinylformamide units in polymerized form. They are prepared by free radical polymerization of N-vinylformamide and subsequent partial hydrolysis of the polymer thus obtained. The partially hydrolyzed poly-N-vinylformamides are used, for example, as retention aids, drainage aids and flocculants in papermaking.
  • the prior German Application 101 38 631.1 discloses a process for the production of coated paper having a high level of whiteness, a base paper or a precoated paper being treated with at least one substance which enhances the efficiency of optical brighteners and then being coated with a paper coating slip which contains an optical brightener.
  • Examples of compounds which enhance the efficiency of optical brighteners are homo- and copolymers of N-vinylcarboxamides or the polymers obtainable therefrom by hydrolysis and containing vinylamine units.
  • this object is achieved, according to the invention, by a process for the production of paper, board and cardboard by draining a paper stock in the presence of at least one cationic polymer on a wire, if a mixture of at least one substantially linear, cationic polyelectrolyte and an optical brightener is added to the paper stock before sheet formation, at least two parts by weight of the polyelectrolyte being used per part by weight of the optical brightener.
  • Cationic polyelectrolytes are to be understood as meaning polymers which carry positive charges and which are distributed over the polymer chain. Cationic polyelectrolytes are furthermore to be understood as meaning those substances which may be nonionic in the dry state but, owing to their basic character, are protonated in water or other solvents and hence carry positive charges.
  • the mixtures which are added to the paper stock before sheet formation usually contain
  • the cationic polyelectrolytes (ii) which can be used in the novel process are known.
  • polymers which are known by the following chemical trivial names can be used: polyvinylamine, polyallylamine, poly(diallyldimethylammonium chloride), cationic polyvinylformamide, cationic polyvinylpyrrolidone, cationic polyvinylacetamide, cationic polyvinylmethylformamide, cationic polyvinylmethylacetamide, poly(dimethylaminopropylmethacrylamide), poly(dimethylaminoethyl acrylate), poly(diethylaminoethyl acrylate), poly(acryloylethyltrimethylammonium chloride), poly(acrylamidopropyltrimethylammonium chloride), poly(methacrylamidopropyltrimethylammonium chloride), cationic polyacrylamide, poly(vinylpyridine), hexadimethrine bromide, poly(
  • Polymers containing vinylamine units such as cationic polyvinylformamides and polyvinylamine, and furthermore cationic polyacrylamide and poly(diallyldimethylammonium chloride) are preferred. Polymers which contain vinylamine units and are in the form of the free bases or salts are particularly preferred.
  • the cationic polyelectrolytes (ii) which can be used in the novel process have different molecular weights which are characterized below with the aid of the Fikentscher K values.
  • the molecular weights of the cationic polyelectrolytes which can be used according to the invention are not limited. As a rule, they correspond to K values of from 20 to 200, preferably from 30 to 150, particularly preferably from 40 to 100 (the stated K values are determined according to H. Fikentscher in 5% strength aqueous sodium chloride solution at pH 7, 25° C. and a polymer concentration of 0.1% by weight).
  • the very particularly preferred polymers containing vinylamine units such as cationic polyvinylformamides, contain vinylamine and vinylformamide units according to the formula (I) where the ratio n:m is from 99:1 to 1:99 and p may be from 30 to 30 000.
  • Some or all of the vinylamine units of the polymers may be present as salts with mineral acids, such as hydrochloric acid, sulfuric acid or phosphoric acid, or as salts with organic acids (e.g. formic acid, acetic acid, propionic acid, toluenesulfonic acid, benzenesulfonic acid or methanesulfonic acid).
  • the polymers containing vinylamine units are prepared by polymerizing, for example, N-vinylformamide of the formula (II) to give a polyvinylformamide of the formula (III) and partly cleaving this with removal (or hydrolysis) of the formyl group to give the copolymer (I). On complete hydrolysis of the formyl groups of polyvinylformamides, polyvinylamines are obtained.
  • the free bases of the polymers containing vinylamine units are formed if the hydrolysis is carried out using bases, such as sodium hydroxide solution or potassium hydroxide solution, whereas the vinylamine units of the polymers are present in salt form on hydrolysis with acids.
  • a preferred degree of hydrolysis of the carboxamido groups is from 5 to 90, particularly preferably from 10 to 50, mol %, based on the N-vinylcarboxamide units contained in the N-vinylcarboxamide polymers.
  • the cleavage of the N-vinylcarboxamide units contained in the polymer is preferably effected in the presence of bases, for example sodium hydroxide, potassium hydroxide, alkaline earth metal hydroxides, ammonia or amines.
  • Cationic polymers of N-vinylformamide are obtained in a particularly suitable manner by hydrolytically cleaving homopolymers of N-vinylformamide with defined amounts of acid or base to give the desired degree of hydrolysis, as described in EP-B-0 071 050 mentioned as prior art.
  • the amino groups formed thereby on the polymer chain are protonated to a greater or lesser extent depending on the pH of the solution and thus impart a more or less cationic character to the polymer.
  • Elimination of the formyl group during the hydrolysis is effected in general at from 20 to 200° C., preferably from 40 to 180° C., in the presence of acids or bases.
  • the hydrolysis in the presence of acids or bases is particularly preferably carried out at from 70 to 90° C.
  • an acid such as hydrochloric acid, hydrobromic acid, phosphoric acid or sulfuric acid, per formyl group equivalent in the poly-N-vinylformamide are required, for example, with the acidic hydrolysis.
  • the pH in the acidic hydrolysis is, for example, from 2 to 0, preferably from 1 to 0.
  • hydrolysis of the formyl groups of the poly-N-alkyl-N-vinylformamide can also be carried out in an alkaline medium, for example at a pH of from 11 to 14.
  • This pH is preferably established by adding alkali metal bases, e.g. sodium hydroxide solution or potassium hydroxide solution.
  • alkali metal bases e.g. sodium hydroxide solution or potassium hydroxide solution.
  • ammonia, amines and/or alkaline earth metal bases From 0.05 to 1.5, preferably from 0.4 to 1.0, equivalents of a base are used for the alkaline hydrolysis.
  • the cleavage can also be carried out at high temperatures, for example above 100° C., preferably from 120 to 180° C., particularly preferably from 140 to 160° C., in the presence of a solvent, e.g. water, in the absence of acids or bases. This is preferably carried out under conditions above the critical point of the solvent, for example using supercritical water.
  • a solvent e.g. water
  • carboxylic acid for example formic acid
  • a salt thereof is obtained as the byproduct.
  • the solutions thus obtainable can be used without further working-up in the novel process, but the hydrolysis or solvolysis products can also be separated off.
  • the solutions obtained are treated, for example, with ion exchangers or subjected to an ultrafiltration.
  • cationic polyacrylamides which can be used for the novel process are known, cf. D. Horn, F. Linhart, in Paper Chemistry, ed. J. C. Roberts, 2 nd edition, Blackie Academic & Professional, Glasgow (1996), pages 66-67, and literature cited there.
  • acrylic acid or methacrylic acid can be incorporated as polymerized units into the polymer chain up to an amount such that the total charge of the polymer remains positive.
  • the poly(diallyldimethylammonium chloride) which can be used in the novel process can be characterized, for example, with the aid of the formula (V) where n may be from 30 to 30 000.
  • Such polymers have been known for many years, cf. D. Horn, F. Linhart, in Paper Chemistry, ed. J. C. Roberts, 2 nd edition, Blackie Academic & Professional, Glasgow (1996), page 70; G. Butler, in Polymeric Amines and Ammonium Salts, ed. E. J. Goethals, Pergamon Press, Oxford 125, (1980).
  • diallyldialkylammonium chlorides are also suitable, for example those of the polymer formula (VI), where R 1 and R 2 , independently of one another, may be alkyl of 2 to 4 carbon atoms, it also being possible for R 1 or R 2 to be hydrogen, and where n may be from 30 to 30 000.
  • Preferably used cationic polyelectrolytes are hydrolyzed homopolymers of N-vinylformamide having a degree of hydrolysis of from 1 to 99 mol %, copolymers of acrylamide and cationic monomers (e.g. amino- or ammonium-containing monomers), polymers of diallyldimethylammonium chloride and the polyamidoamine/epichlorohydrin resins which can be used as wet strength agents.
  • Cationic polyelectrolytes which are obtainable by copolymerization of starting monomers of the abovementioned polyelectrolytes can of course also be used for the novel process.
  • copolymers of vinylformamide (formula (II)) and diallyldimethylammonium chloride or of vinylformamide and basic acrylates as described in EP-B-0 464 043, and also copolymers of acrylamide and diallyldimethylammonium chloride or other diallyldialkylammonium chlorides can also be used.
  • the solubility of the cationic polyelectrolytes in the solvent (iii) used is as a rule from at least 1% by weight to complete solubility, for example at 20° C.
  • the mixing ratios in the mixtures of the optical brighteners and the cationic polyelectrolytes may be from 1:2 to 1:100, but a substantial excess of cationic polyelectrolytes is advantageous. Particularly advantageous is the use of optical brighteners and cationic polyelectrolytes in the weight ratio of from 1:2 to 1:50, very particularly preferably from 1:5 to 1:20.
  • optical brighteners (i) can be used for the novel process.
  • brighteners as described in Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition, 2000 Electronic Release, OPTICAL BRIGHTENERS—Chemistry of Technical Products, Section 2.1 to Section 2.9 can be used.
  • Suitable optical brighteners (i) belong, for example, to the group consisting of the distyrylbenzenes, for example cyano-substituted 1,4-distyrylbenzenes having cyano groups in the positions 2′ and 3′′ [CAS Reg. No. 79026-03-2] or in positions 2′ and 2′′ [13001-38-2], 3′ and 3′′ [36755-00-7], 3′ and 4′′ [79026-02-1] and 4′ and 4′′ [13001-40-6], or amphoteric compounds, e.g.
  • 1,3,5-triazinyl derivatives of 4,4′-diaminostilbene-2,2′-disulfonic acid such as anilino derivatives which carry the following radicals in each case in position 3 on the triazine rings: methoxy (CAS Reg. No.
  • N-bis(hydroxyethyl)amino and, additionally on the anilino group, sulfo in position 3 (CAS Reg. No. [12224-02-1]), N-bis(2-hydroxypropyl)amino and, additionally on the anilino group, sulfo in position 4 (CAS Reg. No. [99549-42-5]), N-bis(hydroxyethyl)amino and, additionally on the anilino group, sulfo in position 4 (CAS Reg. No. [16470-24-9]), N-hydroxyethyl-N-methyl-amino- and, additionally on the anilino group, sulfo in position 4 (CAS Reg. No.
  • stilbenyl-2H-naphtho[1,2-d]triazoles such as the sodium salt of 4-(2H-naphtho[1,2-d]triazol-2-yl)stilbene-2-sulfonic acid [6416-68-8] or those which carry sulfo in position 6 on the naphthol ring and at position 2 of the stilbene skeleton [2583-80-4], or cyano in position 2 and chlorine in position 4′ on the stilbene skeleton [5516-20-1] or, for example, bis(1,2,3-triazol-2-yl)stilbenes, such as 4,4′-bis(4-phenyl-1,2,3-triazol-2-yl)stilbene-2,2′-disulfonic acid dipotassium salt [52237-03-3] or 4,4′-bis(4-(4′-sulfophenyl)-1,2,3-triazol-2-yl)stilbene-2,2′-disulfonic acid
  • stilbenylbenzoxazoles for example 5,7-dimethyl-2-(4′-phenylstilben-4-yl)benzoxazole [40704-04-9], 5-methyl-2-(4′-(4′′-methoxycarbonyl)-phenylstilben-4-yl)-benzoxazole [18039-18-4] or those which carry other heterocycles in the 4′′ position, e.g. [64893-28-3], or bis(benzoxazoles), e.g.
  • ethylene-, thiophene-, naphthylene-, phenylethylene- or stilbene-bridged bisbenzoxazoles such as those having the CAS numbers [1041-00-5], [2866-43-5], [7128-64-5], [5089-22-5], [1552-46-1], [1533-45-5] or [5242-49-9].
  • furans benzo[b]furans and benzimidazoles
  • bis(benzo[b]furan-2-yl)biphenyls for example sulfonated 4,4′-bis(benzo[b]furan-2-yl)biphenyls
  • cationic benzimidazoles for example 2,5-di(1-methylbenzimidazol-2-yl)furan [4751-43-3], [72829-17-5], [74878-56-1], [74878-48-1] or [66371-25-3], or 1,3-diphenyl-2-pyrazolines, e.g.
  • 1-(4-amidosulfonylphenyl)-3-(4-chlorophenyl)-2-pyrazoline [2744-49-2], [60650-43-3], [3656-22-2], [27441-70-9], [32020-25-0], [61931-42-8] or [81209-71-4], and tertiary and quaternary amine salts of 1,3-diphenyl-2-pyrazoline derivatives, e.g. [106359-93-7], [85154-08-1], [42952-22-7], [63310-12-3][12270-54-1] or [36086-26-7], and coumarins, e.g.
  • 4,4′-Distyrylbiphenyl derivatives or stilbene derivatives which are substituted by up to 6, particularly preferably by 2, 4 or 6, sulfo groups can preferably be used, preferably the Blankophor® brands from Bayer AG, particularly preferably Blankophor® P and Blankophor® PSG, preferably furthermore the Tinopal® brands from Ciba Specialty Chemicals, particularly preferably Tinopal® MC liquid, Tinopal® ABP-Z liquid, Tinopals SPP-Z liquid and Tinopal® SK-B liquid and preferably furthermore the Leukophor® brands from Clariant AG, particularly preferably Leukophor® APN, UO, NS or SHR.
  • optical brighteners and cationic polymers which contain polymerized vinylformamide units can be added separately from one another to the paper stock, the cationic polyelectrolyte being metered first, followed by the optical brightener, or the sequence of addition being reversed.
  • Suitable solvents (iii) for the mixtures are, for example, water, methanol, ethanol, isopropanol, n-propanol, n-butanol, dimethylformamide and N-methylpyrrolidone, water being preferred.
  • concentration should be chosen so that the respective metering processes and subsequent dilution processes can be carried out optimally owing to, for example, the viscosity of the mixture. Optimum viscosities for various metering processes and dilution processes are known to a person skilled in the art. Customary concentrations of the mixtures are from 2 to 20% by weight.
  • the molecular weight of the cationic polyelectrolyte to be used according to the invention should be adapted to the respective desired profile of the polyelectrolytes. If the cationic polyelectrolyte is to act, for example, as a retention aid in papermaking, cationic polymers having a very high molecular weight are preferably used. If the cationic polymers are to be effective as fixing agents or as strength agents, cationic polymers having medium to low molecular weights are used. The addition of retention aids and drainage aids to the paper stock before drainage on the wire is part of the general prior art.
  • the cationic polymers generally used have very high molecular weights of from 2 to 20 million Dalton (cf. F.
  • cationic polymers having molecular weights of from 500 000 to 2 million Dalton are also successfully used as retention aids.
  • the amounts of these polymers used are from 50 g/t to 5 kg/t, preferably from 100 g/t to 2 kg/t, based on dry paper stock.
  • the cationic fixing agents added in many cases to the paper stock have substantially lower molecular weights which differ very greatly depending on the chemical nature and the function of the polymer and are from 10 000 to 500 000 Dalton.
  • the amounts of fixing agents used are from 100 g/t to 2 kg/t, based on dry paper stock.
  • the molecular weights of polymeric cationic strength agents vary in the very wide range of from a few hundred Dalton, as is possible, for example, in the case of reactive wet-strength agents through 100 000 to 500 000 Dalton in the case of synthetic dry-strength agents (J. Marton, Dry-Strength Additives, in Paper Chemistry, J. C.
  • the present invention also relates to the use of mixtures of
  • the mixtures of the two components (i) and (ii) are metered into the paper stock by the methods customary in the paper industry. This means that the mixtures are diluted with water continuously or batchwise to concentrations of from 0.01 to 1% by weight before addition to the paper stock, in order to achieve more rapid and more uniform mixing with the paper stock. However, this does not mean that the mixtures cannot be added undiluted or in less dilute form to the paper stock.
  • the feed point of the mixtures depends on the requirements and on the desired profile of the cationic polyelectrolyte in the mixture. If the mixture is intended not only to increase the whiteness of the paper but also simultaneously to increase the retention and the drainage rate, addition in the low-density stock shortly before the head box, before or after the pressure screen, is appropriate.
  • the mixture can be added throughout the stock preparation region, for example also in the high-density stock, in the mixing chest, in the machine chest or to the individual stock components before they are mixed. If the cationic polyelectrolyte in the mixture is to act as a strength agent, it is advisable to add the mixture at a point which is customary for the addition of strength agents, for example in the mixing chest or machine chest, but also before the beater or in the low-density stock region. For all applications, the optimum metering point must be determined in each individual case by practical experiments.
  • the novel process is preferably used in the production of highly white papers and cardboards whose starting materials should already have sufficient basic whiteness.
  • Highly white fibers and fillers are therefore mainly used for this purpose.
  • the fibers which may be used primarily include chemical pulps, for example bleached sulfate pulp based on conifers, birches or eucalyptus, and beech sulfite pulp, based on spruces and on beeches and other deciduous trees, but also chemical pulps which are obtained from wood by other processes.
  • Bleached mechanical pulps e.g.
  • groundwood, pressure groundwood (PGW), refiner mechanical pulp (RMP), thermomechanical pulp (TMP) or chemothermomechanical pulp (CTMP, APTMP and further variants), based on conifers and aspen or other suitable deciduous trees, are furthermore suitable.
  • fibers from annuals e.g. cotton, cotton linters, bleached straw pulp from straw of various cereal species, bleached bagasse pulp, hemp, flax, kenaf, etc.
  • a very important fiber of the novel process is a bleached fiber freed from printing inks and based on waste graphic arts papers, i.e. deinked pulp (DIP).
  • DIP deinked pulp
  • the fillers suitable for the novel process are generally aluminum silicates, such as kaolin or modifications obtained by further treatment thereof, magnesium silicates, e.g. talc, calcium carbonate in the form of ground marble or limestone or in the form of natural or ground chalk or in the form of precipitated calcium carbonate, calcium sulfate in the form of gypsum, or titanium dioxide.
  • magnesium silicates e.g. talc
  • calcium sulfate in the form of gypsum or titanium dioxide.
  • the papers, boards or cardboards produced by the novel process can be printed on in conventional processes, for example offset, letterpress or gravure printing processes, flexographic printing processes or digital printing processes, e.g. laser printing or inkjet printing processes, but can also be otherwise processed or converted, e.g. coated.
  • the novel process helps the person skilled in the art to perform the difficult task of producing papers, boards and cardboards in an improved process or with higher quality and simultaneously increased whiteness with relatively simple means and high flexibility.
  • K values of the polymers were determined according to H. Fikentscher, Cellulose-Chemie, 13 (1932), 58-63 and 71-74, in 5% strength by weight aqueous solution at pH 7, 25° C. and a polymer concentration of 0.1% by weight.
  • a paper having a basis weight of 80 g/m 2 was produced according to the prior art on an experimental paper machine from an aqueous paper stock comprising 70 parts of birch sulfate pulp, 30 parts of pine sulfate pulp, 20 parts of chalk filler (Hydrocarb® 60 from Plüss-Staufer AG), 0.05 part of stock deaerator (Afranil® SLO from BASF Aktiengesellschaft), 1.0 part of engine size (Basoplast® 2018 LC from BASF Aktiengesellschaft) and 0.5 part of soluble cationic starch (Solvitose® BPN from Avebe).
  • aqueous paper stock comprising 70 parts of birch sulfate pulp, 30 parts of pine sulfate pulp, 20 parts of chalk filler (Hydrocarb® 60 from Plüss-Staufer AG), 0.05 part of stock deaerator (Afranil® SLO from BASF Aktiengesellschaft), 1.0 part of engine size (Basoplast® 2018 LC from BA
  • the whiteness and the calorimetric values according to the CIELAB system were determined for the paper obtained as the end product. Furthermore, the paper obtained as the end product was checked visually for fluorescence by illumination with an ultraviolet lamp. The complete fixing of the brightener in the paper was investigated by impregnating a strip of highly absorptive white wood-free paper with white water and checking visually for fluorescence under illumination with ultraviolet light.
  • the novel process gives very good retention and simultaneously greatly increases the whiteness of the paper, the desired shift in hue to blue and red occurring.
  • Particularly surprising is the extent of the increase in whiteness when it is considered that only 0.005 part of optical brightener, based on about 122 parts of solid paper stock, was used as a proportion of the mixture.

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  • Paper (AREA)
US10/498,085 2001-12-17 2002-12-06 Production of paper board and cardboard Abandoned US20050061461A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10162052A DE10162052A1 (de) 2001-12-17 2001-12-17 Verfahren zur Herstellung von Papier, Pappe und Karton
DE101620527 2001-12-17
PCT/EP2002/013843 WO2003052205A1 (de) 2001-12-17 2002-12-06 Verfahren zur herstellung von papier, pappe und karton

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US (1) US20050061461A1 (de)
EP (1) EP1458933A1 (de)
JP (1) JP2005513283A (de)
AU (1) AU2002361983A1 (de)
CA (1) CA2469758A1 (de)
DE (1) DE10162052A1 (de)
WO (1) WO2003052205A1 (de)

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US20040154764A1 (en) * 2001-08-13 2004-08-12 Thierry Blum Method for production of coated paper with extreme whiteness
US20040182533A1 (en) * 2001-09-03 2004-09-23 Thierry Blum Method for increasing the whiteness of paper by means of cationic polyelectrolytes
US20070169903A1 (en) * 2006-01-25 2007-07-26 Covarrubias Rosa M Papermaking processes using coagulants and optical brighteners
US20080041546A1 (en) * 2004-11-29 2008-02-21 Basfaktiengesellschaft Paper Sizing Agent
US20080073617A1 (en) * 2004-10-27 2008-03-27 Robert Cockcroft Compositions of Fluorescent Whitening Agents
US20090025895A1 (en) * 2006-02-20 2009-01-29 John Stuart Cowman Process for the Manufacture of Paper and Board
US20090272506A1 (en) * 2004-12-17 2009-11-05 Basf Aktiengesellschaft Papers with a high filler material content and high dry strength
WO2012065951A1 (en) * 2010-11-16 2012-05-24 Basf Se Manufacture of cellulosic pulp sheets
US8349134B2 (en) 2004-11-23 2013-01-08 Basf Se Method for producing high dry strength paper, paperboard or cardboard

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SE537486C2 (sv) * 2012-03-05 2015-05-19 Tetra Laval Holdings & Finance System och sätt för tryckning

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US3901857A (en) * 1972-11-11 1975-08-26 Bayer Ag Process for the production of high molecular weight cationic acrylamide copolymers
US3907758A (en) * 1973-09-12 1975-09-23 Bayer Ag Additives for paper
US4210488A (en) * 1977-10-13 1980-07-01 Reuss Peter J Process for improving the dry strength of paper and for improving the effect of optical brighteners in the preparation or coating of paper
US6273998B1 (en) * 1994-08-16 2001-08-14 Betzdearborn Inc. Production of paper and paperboard

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040154764A1 (en) * 2001-08-13 2004-08-12 Thierry Blum Method for production of coated paper with extreme whiteness
US7641765B2 (en) * 2001-08-13 2010-01-05 Basf Aktiengesellschaft Method for production of coated paper with extreme whiteness
US20040182533A1 (en) * 2001-09-03 2004-09-23 Thierry Blum Method for increasing the whiteness of paper by means of cationic polyelectrolytes
US7731820B2 (en) 2004-10-27 2010-06-08 Ciba Specialty Chemicals Corporation Compositions of fluorescent whitening agents
US20080073617A1 (en) * 2004-10-27 2008-03-27 Robert Cockcroft Compositions of Fluorescent Whitening Agents
US8349134B2 (en) 2004-11-23 2013-01-08 Basf Se Method for producing high dry strength paper, paperboard or cardboard
US8512520B2 (en) * 2004-11-29 2013-08-20 Basf Aktiengesellschaft Paper sizing agent
US20080041546A1 (en) * 2004-11-29 2008-02-21 Basfaktiengesellschaft Paper Sizing Agent
US20090272506A1 (en) * 2004-12-17 2009-11-05 Basf Aktiengesellschaft Papers with a high filler material content and high dry strength
US8778139B2 (en) 2004-12-17 2014-07-15 Basf Aktiengesellschaft Papers with a high filler material content and high dry strength
US20070169903A1 (en) * 2006-01-25 2007-07-26 Covarrubias Rosa M Papermaking processes using coagulants and optical brighteners
US20090025895A1 (en) * 2006-02-20 2009-01-29 John Stuart Cowman Process for the Manufacture of Paper and Board
WO2012065951A1 (en) * 2010-11-16 2012-05-24 Basf Se Manufacture of cellulosic pulp sheets
US8916026B2 (en) 2010-11-16 2014-12-23 Basf Se Manufacture of cellulosic pulp sheets
US9567710B2 (en) 2010-11-16 2017-02-14 Basf Se Manufacture of cellulosic pulp sheets

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AU2002361983A1 (en) 2003-06-30
WO2003052205A1 (de) 2003-06-26
CA2469758A1 (en) 2003-06-26
DE10162052A1 (de) 2003-06-26
EP1458933A1 (de) 2004-09-22
JP2005513283A (ja) 2005-05-12

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