WO2004022848A1

WO2004022848A1 - Method for glueing paper, paperboard and cardboard

Info

Publication number: WO2004022848A1
Application number: PCT/EP2003/008093
Authority: WO
Inventors: Simon Champ; Günther GRIMM; Roland Ettl; Rainer Dyllick-Brenzinger
Original assignee: Basf Aktiengesellschaft
Priority date: 2002-08-14
Filing date: 2003-07-24
Publication date: 2004-03-18
Also published as: AU2003251464A1; DE10237912A1

Abstract

The invention relates to a method for mass glueing paper, cardboard and paperboard by adding anionically adjusted aqueous dispersions of reactive glueing agents, at least one retention agent and at least one cationic polymer to an aqueous slurry of cellulose fibres and then dewatering the paper material. The invention also relates to cationic polymers selected from the group of polymers containing vinylamine units, polymers containing vinylguanidine units, polyethylenimines, polyamidomines grafted with ethyleneimine and/or polydiallyldimethylammonium chlorides as fixing agents and promoters for anionically adjusted aqueous dispersions of a reactive glueing agent during mass glueing of paper, cardboard and paperboard.

Description

Process for sizing paper, cardboard and cardboard

description

The invention relates to a process for the mass sizing of paper, cardboard and cardboard by adding aqueous dispersions of anionically dispersed reactive sizing agents and at least one retention agent to an aqueous slurry of cellulose fibers and dewatering the paper stock.

WO-A-00/23651 discloses aqueous, anionically sized sizing agent dispersions which can be obtained by dispersing a reactive sizing agent such as alkyldiketene or alkenylsuccinic anhydride in the presence of an anionic dispersant in water. The dispersants used are, for example, condensation products from naphthalenesulfonic acid and formaldehyde or condensation products from phenol, phenolsaufonic acid and formaldehyde or amphiphilic copolymers of hydrophobic monoethylenically unsaturated monomers and hydrophilic monomers with an anionic group. The dispersants can be in the form of the free acids, the alkali metal, alkaline earth metal and / or the ammonium salts. The sizing agent dispersions are added to the paper stock, where appropriate the dewatering, flocculation and retention aids and fixing agents normally used in paper manufacture can also be used. The retention and distribution of the reactive sizes in the paper still need to be improved.

The present invention has for its object to provide an improved process for the sizing of paper, cardboard and cardboard with aqueous dispersions of anionically dispersed reactive sizing agents in the presence of at least one retention aid, with a better fixation of the reactive sizing agents and a compared to the prior art receives faster sizing training.

The object is achieved according to the invention with a process for the mass sizing of paper, cardboard and cardboard by adding anionically adjusted aqueous dispersions of reactive sizing agents and at least one retention agent to an aqueous slurry of cellulose fibers and dewatering of the pulp, if one goes to the aqueous slurry of cellulose fibers additionally adds at least one cationic polymer. The invention also relates to the use of cationic polymers from the group consisting of vinylamine unit-containing polymers, vinylguanidine unit-containing polymers, polyethyleneimines, with ethylenei in grafted polyamidoamines and / or polydiallyldimethylammonium chlorides as fixatives and promoters for anionically adjusted aqueous dispersions of a reactive sizing agent of paper in the mass sizing. Cardboard and cardboard.

Suitable cellulose fibers are, for example, fibers obtained from wood pulp and all egg plants. For example, wood pulp includes wood pulp, thermomechanical material (TMP), chemothermomechanical material (CTMP), pressure sanding, semi-pulp, high-yield pulp and refiner mechanical pulp (RMP) as well as waste paper. Also suitable are pulps that can be used in bleached or unbleached form. Examples of these are sulfate, sulfite and sodium pulps. Unbleached pulps, which are also referred to as unbleached kraft pulp, are preferably used. The fibers mentioned can be used alone or in a mixture.

Suitable solvents are, for example, Cχ to C alkyl ketene dimers, C ₅ to C alkyl or C ₅ to C ₂ alkenylsuccinic acid anhydrides, C to C ₃₆ alkyl isocyanates and / or organic isocyanates such as dodecyl isocyanate, octadecyl isocyanate , Tetradecyl isocyanate, hexadecyl isocyanate, eicosyl isocyanate and decyl isocyanate. Bulk sizing agents used with preference are alkyl ketene dimers and long-chain alkyl or alkenyl succinic acid anhydrides.

Examples of alkyl ketene dimers are stearydiketene, lauryl diketene, palmityldiketene, oleyl diketene, behenyl diketene or mixtures thereof. Substituted succinic anhydrides suitable as mass sizing agents are, for example, decenylsuccinic anhydride, n-octadecenylsuccinic anhydride, dodecenylsuccinic anhydride and n-hexadecenylsuccinic anhydride.

The alkyl diketenes and long-chain alkenyl or alkyl succinic acid anhydrides which are preferably suitable as sizing agents and processes for the preparation of anionically adjusted aqueous dispersions of such reactive sizing agents are known from WO-A-00/23651, cf. Pages 2 to 12. To produce size dispersions, the reactive sizes are usually heated to a temperature above their melting point and emulsified in molten form in water under the action of shear forces. The liquid alkenyl succinic anhydride can be emulsified at room temperature. Here- for example one uses homogenizers. In order to stabilize the dispersed sizing agents in the aqueous phase, at least one anionic dispersant from the group of the condensation products is used

(a) naphthalenesulfonic acid and formaldehyde,

(b) phenol, phenolsulfonic acid and formaldehyde,

(c) naphthalenesulfonic acid, formaldehyde and urea and

(d) phenol, phenol sulfonic acid, formaldehyde and urea.

The anionic dispersants can be in the form of the free acids, the alkali metal, alkaline earth metal and / or

Ammonium salts are present. The ammonium salts can be derived from ammonia as well as from primary, secondary and tertiary amines, e.g. the ammonium salts of dimethylamine, trimethylamine, hexylamine, cyclohexylamine, dicyclohexylamine, ethanolamine, diethanolamine and triethanolamine are suitable. The condensation products described above are known and commercially available. They are produced by condensing the constituents mentioned, it being possible to use the corresponding alkali metal, alkaline earth metal or ammonium salts instead of the free acids. Acids such as sulfuric acid, p-toluenesulfonic acid and phosphoric acid are suitable as catalysts in the condensation. Naphthalenesulfonic acid or its alkali metal salts are condensed with formaldehyde, preferably in a molar ratio of 1: 0.1 to 1: 2 and mostly in a molar ratio of 1: 0.5 to 1: 1. The molar ratio for the production of condensates from phenol, phenolsulfonic acid and formaldehyde is also in the range given above, with any mixtures of phenol and phenolsulfonic acid being used instead of naphthalenesulfonic acid in the condensation with formaldehyde. Instead of phenolsulfonic acid, one can also use the alkali metal and ammonium salts of phenolsulfonic acid. The condensation of the starting materials specified above can optionally also be carried out in the presence of urea. For example, based on naphthalenesulfonic acid or on the mixture of phenol and phenolsulfonic acid, 0.1 to 5 moles of urea are used per mole of naphthalenesulfonic acid or per mole of the mixture of phenol and phenolsulfonic acid.

The condensation products have, for example, molar masses in the range from 800 to 100,000, preferably 1,000 to 30,000 and in particular 4,000 to 25,000. The anionic dispersants used are preferably salts which are, for example, by neutralizing the condensation products with lithium hydroxide, sodium hydroxide, potassium hydroxide or ammonia. The pH of the salts is, for example, in the range from 7 to 10.

Amphiphilic copolymers are also suitable as anionic dispersants

(i) hydrophobic monoethylenically unsaturated monomers and

(ii) hydrophilic monomers with an anionic group such as monoethylenically unsaturated carboxylic acids, monoethylenically unsaturated sulfonic acids, monoethylenically unsaturated phosphonic acids or mixtures thereof.

Suitable hydrophobic monoethylenically unsaturated monomers

(a) are, for example, olefins having 2 to 150 carbon atoms, styrene, α-methylstyrene, ethylstyrene, 4-methylstyrene, acrylonitrile, methacrylonitrile, esters of monoethylenically unsaturated C ₃ to Cs carboxylic acids and monohydric alcohols, A ide Acrylic acid or methacrylic acid with C 1 to C ₂ alkylamines, vinyl esters of saturated monocarboxylic acids with 2 to 24 C atoms, diesters of maleic acid or fumaric acid with monohydric C 1 -C ₄ alcohols, vinyl ethers of alcohols with 3 to 24 C Atoms or mixtures of the compounds mentioned.

The amphiphilic copolymers contain as hydrophilic monomers

(b) for example C ₃ - to Cir-monoethylenically unsaturated carboxylic acids or their anhydrides, 2-acrylamido-2-methylpropanesulfonic acid,

Vinylsulfonic acid, styrenesulfonic acid, vinylphosphonic acid, salts of the monomers mentioned or mixtures thereof as hydrophilic monomers with an anionic group

polymerized. Aqueous size dispersions which comprise amphiphilic copolymers as an anionic dispersant are particularly preferred

(a) olefins with 4 to 12 carbon atoms, styrene or mixtures thereof as hydrophobic monomers and

(b) Maleic acid, acrylic acid, methacrylic acid, half esters of maleic acid and alcohols with 1 to 25 carbon atoms or alkoxylation products of such alcohols, halabide of maleic acid, salts of the monomers mentioned or mixtures thereof Compounds as hydrophilic monomers with an anionic group

contain polymerized and have a molecular weight M _w of 1,500 to 5,100,000.

Preferred anionic dispersants are copolymers of maleic anhydride with C ₄ - to -C ₂ -01efins, particularly preferably Cs-olefins such as octene-1 and diisobutene. Especially before

10 is diisobutene. The molar ratio between maleic anhydride and olefin is e.g. in the range 0.9: 1 to 3: 1, preferably from 0.95: 1 to 1.5: 1. These copolymers are preferably used in hydrolyzed form as an aqueous solution or dispersions, the anhydride group being open.

15 lies and the carboxyl groups are preferably partially or completely neutralized. The following bases are used for neutralization: alkali metal bases, such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, alkaline earth metal salts such as calcium hydroxide, calcium carbonate, magnesium hydroxide, ammonia, primary,

20 secondary or tertiary amines such as triethylamine, triethanolamine, diethanolamine, ethanolamine, morpholine etc.

If the amphiphilic copolymers are not sufficiently water-soluble in the form of the free acid, they are in the form of

25 water-soluble salts are used, for example using the corresponding alkali metal, alkaline earth metal and ammonium salts. The molar mass M _{w of} the amphiphilic copolymers is, for example, 800 to 250,000, mostly 1,000 to 100,000 and is preferably in the range from 3,000 to 20,000, in particular from

30 1,500 to 10,000. The acid numbers of the amphiphilic copolymers are, for example, 50 to 500, preferably 150 to 300 mg KOH / g polymer.

The amphiphilic copolymers are e.g. in amounts of 0.05 to 35 20, preferably 0.5 to 10 wt .-%, based on the reactive size, used as an anionic dispersant for the preparation of the size dispersions. The amphiphilic copolymers are preferably used in amounts of 0.1 to 2, in particular 0.6 to 1,% by weight, based on the sizing agent to be dispersed. If only amphiphilic copolymers are used as dispersants, aqueous size dispersions are obtained which are formaldehyde-free and stable in storage.

In order to produce aqueous, anionic sizing agent dispersions, 45 one can, for example, submit an aqueous solution of at least one condensation product or at least one amphiphilic copolymer and therein at temperatures of, for example, 20 to 100, preferably 40 to 90 ° C disperse the sizing agent. The sizing agent is preferably added in the form of a melt and dispersed with vigorous stirring or shearing. The resulting dispersion is cooled in each case. In this way, it is possible, for example, to prepare aqueous, anionically sized sizing agent dispersions which contain 6 to 65% by weight of an alkyldiketene or 0.1 to 65% by weight of an alkenylsuccinic acid anhydride in dispersed form as a sizing agent. Highly concentrated size dispersions, for example

10 25 to 60% by weight of an alkyl diketene as a sizing agent in the presence of 0.1 to 5.0% by weight of a condensation product of naphthalenesulfonic acid and formaldehyde or at least one condensation product of (b), (c) and / or (d) dispersed included.

15

Further preferred sizing agent dispersions contain 25 to 60% by weight of an alkyl diketene as a sizing agent and 0.1 to 5.0% by weight of an amphiphilic copolymer

20

(i) 95 to 50% by weight of isobutene, diisobutene, styrene or mixtures thereof and

(ii) 5 to 50% by weight of acrylic acid, methacrylic acid, maleic acid, 25 half esters of maleic acid or mixtures thereof

or a water-soluble salt of such a copolymer.

Such highly concentrated sizing agent dispersions have a relatively low viscosity, e.g. in the range of 20 to

100 mpas (measured with a Brookfield viscometer and a temperature of 20 ° C). In the preparation of the aqueous dispersions, the pH is, for example, from 2 to 8 and is preferably in the range from 3 to 4. Aqueous, anionically sized sizing agent dispersions having an average particle size of the sizing agents in the range from 0 are obtained. 1 to 3, preferably 0.5 to 1.5 μm.

According to the invention, at least one cationic polymer is added to the aqueous slurry of cellulose fibers in addition to the substances already mentioned as a fixing agent and promoter for reactive sizing agents. Examples of cationic polymers are polymers containing vinylamine units, polymers containing vinylguanidine units, polyethyleneimines, polyamidoamines grafted with ethyleneimine and / or polydiallyldimethylammonium chloride. The amount of cationic polymers is, for example 0.001 to 2.0% by weight, preferably 0.01 to 0.1% by weight, based on dry cellulose fibers.

Polymers containing vinylamine units are known, cf. US-A-4,421,602, US-A-5, 334, 287, EP-A-0 216 387, US-A-5, 981, 689, WO-A-00/63295 and US-A-6, 121, 409. They are prepared by hydrolysis of open-chain polymers containing N-vinylcarboxamide units. These polymers are e.g. obtainable by polymerizing N-vinylformamide, N-vinyl-N-methylformamide, N-vinyl acetamide, N-vinyl-N-methylacetamide, N-vinyl-N-ethylacetamide and N-vinyl propionamide. The monomers mentioned can be polymerized either alone or together with other monomers.

All compounds which can be copolymerized therewith come into consideration as monoethylenically unsaturated monomers which are copolymerized with the N-vinylcarboxamides. Examples of these are vinyl esters of saturated carboxylic acids of 1 to 6 carbon atoms such as vinyl formate, vinyl acetate, vinyl propionate and vinyl butyrate and vinyl ethers such as C ± to Cg alkyl vinyl ethers, for example methyl or ethyl vinyl ether. Further suitable comonomers are esters, amides and nitriles of ethylenically unsaturated C ₃ - to Cβ-carboxylic acids, for example methyl acrylate, methyl methacrylate, ethyl acrylate and ethyl methacrylate, acrylic id and methacrylamide as well as acrylonitrile and methacrylonitrile.

Further suitable carboxylic acid esters are derived from glycols or polyalkylene glycols, only one OH group being esterified in each case, for example hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate and acrylic acid monoesters from polyalkylene glycols of 500 to 100 mol Comonomers are esters of ethylenically unsaturated carboxylic acids with amino alcohols such as, for example, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, dimethylaminopropyl acrylate, dimethylaminopropyl ethacrylate, diethylaminopropyl acrylate, dimethylaminobutylaminyl acrylate and acrylate. The basic acrylates can be used in the form of the free bases, the salts with mineral acids such as hydrochloric acid, sulfuric acid or nitric acid, the salts with organic acids such as formic acid, acetic acid, propionic acid or the sulfonic acids or in quaternized form. Suitable quaternizing agents are, for example, methyl sulfate, diethyl sulfate, methyl chloride, ethyl chloride or benzyl chloride. Other suitable comonomers are amides of ethylenically unsaturated carboxylic acids such as acrylamide, methacrylamide and N-alkyl mono- and diamides of monoethylenically unsaturated carboxylic acids with alkyl radicals of 1 to 6 carbon atoms, for example N-methylacrylamide, N, N-dimethyl acrylamide, N- Methyl methacrylamide, N-ethyl acrylamide, N-propylacrylamide and tert. Butylacrylamide and basic (meth) acrylamides, such as dimethylaminoethyl acrylamide, dimethylaminoethyl ethacrylamide, diethylaminoethyl acrylamide, diethylaminoethyl methacrylamide, dimethylaminopropylacrylamide, diethylaminopropylacrylamide, dimethylaminopropyl methacrylamide and diethylaminopropyl methacrylamide.

Also suitable as comonomers are N-vinylpyrrolidone, N-vinylcaprolactam, acrylonitrile, methacrylonitrile, N-vinylimidazole and substituted N-vinylimidazoles such as e.g. N-vinyl-2-methylimidazole, N-vinyl-4-methylimidazole, N-vinyl-5-methylimidazole, N- vinyl-2-ethylimidazole and N-vinylimidazolines such as N-vinylimidazoline, N-vinyl-2- methylimidazoline and N-vinyl-2-ethylimidazoline. In addition to the free bases, N-vinylimidazoles and N-vinylimidazolines are also used in neutralized or in quaternized form with mineral acids or organic acids, the quaternization preferably being carried out with dimethyl sulfate, diethyl sulfate, methyl chloride or benzyl chloride. Diallyldialkylammonium halides such as e.g. Diallyl dimethyl ammonium chloride.

The copolymers contain, for example

- 95 to 5 mol%, preferably 90 to 10 mol% of at least one N-vinylcarboxamide and

- 5 to 95 mol%, preferably 10 to 90 mol% of other monoethylenically unsaturated monomers copolymerizable therewith

in polymerized form. The comonomers are preferably free from acid groups.

To produce vinyl units containing polymers, it is preferable to start from homopolymers of N-vinylformamide or from copolymers which are obtained by copolymerizing

- N-vinylformamide with

Vinylfor iat, vinyl acetate, vinyl propionate, acrylonitrile, N-vinyl caprolactam, N-vinyl urea, N-vinyl pyrrolidone or Cι ~ to Ce alkyl vinyl ether and subsequent hydrolysis of the homopolymers or copolymers to form vinylamine units from the copolymerized N-vinylformamide units, the degree of hydrolysis being, for example, 5 to 100 mol%, preferably 70 to 100 mol%. The polymers described above are hydrolysed by known processes by the action of acids, bases or enzymes. When acids are used as hydrolysis agents, the vinylamine units of the polymers are in the form of the ammonium salt, while the free amino groups are formed in the hydrolysis with bases.

In most cases, the degree of hydrolysis of the homo- and copolymers is 80 to 95 mol%. The degree of hydrolysis of the home polymers is synonymous with the content of vinyl amine units in the polymers. In the case of copolymers which contain vinyl esters in polymerized form, in addition to the hydrolysis of the N-vinylformamide units, hydrolysis of the ester groups can occur with formation of vinyl alcohol units. This is particularly the case if the copolymers are hydrolysed in the presence of sodium hydroxide solution. Polymerized acrylonitrile is also chemically changed during the hydrolysis. This creates, for example, amide groups or carboxyl groups. The homo- and copolymers containing vinylamine units can optionally contain up to 20 mol% of amidine units, which are formed, for example, by reaction of formic acid with two adjacent amino groups or by intramolecular reaction of an amino group with an adjacent amide group, for example of polymerized N-vinylformamide , The molar masses M _{w of} the polymers containing vinylamine units are, for example, 500 to 10 million, preferably 1000 to 5 million (determined by light scattering). This molar mass range corresponds, for example, to K values of 5 to 300, preferably 10 to 250 (determined according to H. Fikentscher in 5% aqueous sodium chloride solution at 25 ° C. and a polymer concentration of 0.5% by weight). Cationic polymers which have K values of 50 to 135 are particularly preferably used.

The polymers containing vinylamine units are preferably used in salt-free form. Salt-free aqueous solutions of polymers containing vinylamine units can be prepared, for example, from the salt-containing polymer solutions described above with the aid of ultrafiltration on suitable membranes at separation limits of, for example, 1000 to 500,000 daltons, preferably 10,000 to 300,000 daltons. The aqueous solutions of other polymers containing amino and / or ammonium groups described below can also be obtained with the aid of ultrafiltration in a salt-free form. Derivatives of polymers containing vinylamine units can also be used as cationic polymers. For example, it is possible to produce a large number of suitable derivatives from the polymers containing vinylamine units by amidation, alkylation, sulfonamide formation, urea formation, thiourea formation, carbamate formation, acylation, carboxymethylation, phosphonomethylation or Michael addition of the amino groups of the polymer. Of particular interest here are uncrosslinked polyvinylguanidines which are obtained by reacting polymers containing vinylamine units, preferably polyvinylamines, with cyanamide (R! R ² N-CN, where R ¹ , R2 = H, C 1 -C 4 -alkyl, C ₃ - to Cg-cycloalkyl, phenyl, benzyl, alkyl-substituted phenyl or naphthyl) are accessible, cf. US-A-6, 087, 448, column 3, line 64 to column 5, line 14.

The polymers containing 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 can be obtained by free-radically polymerizing, for example, N-vinylformamide in an aqueous medium in the presence of at least one of the graft bases mentioned, together with copolymerizable other monomers, and then hydrolyzing the grafted vinylformamide units to vinylamine units in a known manner.

Other suitable cationic polymers are polyethyleneimines, which can be prepared, for example, by polymerizing ethyleneimine in aqueous solution in the presence of acid-releasing compounds, acids or Lewis acids as a catalyst. Polyethyleneimines, for example, have molecular weights of up to 2 million, preferably from 200 to 1,000,000. Polyethyleneimines with molecular weights of 500 to 750,000 are particularly preferably used. The polyethyleneimines can optionally be modified, e.g. alkoxylated, alkylated or amidated. They can also be subjected to Michael addition or plug synthesis. The derivatives of polyethyleneimines obtainable here are also suitable as cationic polymers.

Polyamidoamines grafted with ethyleneimine are also suitable, which can be obtained, for example, by condensing dicarboxylic acids with polyamines and subsequently grafting ethyleneimine. Suitable polyamidoamines are obtained, for example, by reacting dicarboxylic acids with 4 to 10 carbon atoms with polyalkylene polyamines which contain 3 to 10 basic nitrogen atoms in the molecule. Examples of dicarboxylic acids are succinic acid, maleic acid, adipic acid, glutaric acid, suberic acid, sebacic acid or terephthalic acid. Mixtures of dicarboxylic acids can also be used in the preparation of the polyamidoamines, as can mixtures of several polyalkylene polyamines. Suitable polyalkylene polyamines are, for example, diethylene triamine, triethylene tetramine, tetraethylene penta amine, dipropylene triamine, tripropylene tetramine, dihexamethylene triamine, aminopropylethylenediamine and bis-aminopropylethylenediamine. The dicarboxylic acids and polyalkylene polyamines are used to produce the poly

10 amidoamines heated to higher temperatures, e.g. to temperatures in the range of 120 to 220, preferably 130 to 180 ° C. The water generated during the condensation is removed from the system. Lactones or lactams of carboxylic acids having 4 to 8 carbon atoms can optionally also be used in the condensation. Per

15 moles of a dicarboxylic acid are used, for example, 0.8 to 1.4 moles of a polyalkylene polyamine. These polyamidoamines are grafted with ethyleneimine. The grafting reaction is carried out, for example, in the presence of acids or Lewis acids such as sulfuric acid or boron trifluoride etherates at temperatures of, for example, 80 to

20 100 ° C carried out. Compounds of this type are described for example in DE-B-24 34 816.

The optionally crosslinked polyamidoamines, which may also be additionally crosslinked with ethyleneimine before crosslinking.

25 grafted are considered as cationic polymers. The crosslinked polyamidoamines grafted with ethyleneimine are water-soluble and have, for example, an average molecular weight M _w of 3000 to 2 million daltons. Typical crosslinkers are, for example, epichlorohydrin or bischlorohydrin ethers of alkylene glycols and polyalkylene glycols.

30

Polyallylamines are also suitable as cationic polymers. Polymers of this type are obtained by homopolymerizing allylamine, preferably in a form neutralized with acids, or by copolymerizing allylamine with other mono-

35 ethylenically unsaturated monomers described above as comonomers for N-vinylcarboxamides.

In addition, water-soluble crosslinked polyethyleneimines are suitable, which can be obtained by reacting polyethyleneimines with crosslinking agents such as

40 epichlorohydrin or bischlorohydrin ethers of polyalkylene glycols with 2 to 100 ethylene oxide and / or propylene oxide units are available and still have free primary and / or secondary amino groups. Amidic polyethyleneimines are also suitable, for example by amidating polyethyleneimines

45 with Ci to C ₂ monocarboxylic acids are available. Other suitable cationic polymers are alkylated polyethyleneimines and alkoxylated polyethyleneimines. Used in alkoxylation for example, 1 to 5 ethylene oxide or propylene oxide units per NH unit in the polyethyleneimine.

The above-mentioned cationic polymers have e.g. K values from 8 to 300, preferably 50 to 135 (determined according to H.

Fikentscher in 5% aqueous saline at 25% and a polymer concentration of 0.5% by weight). At a pH of 4.5, for example, they have a charge density of at least 1, preferably at least 4 meq / g polyelectroly.

Cationic polymers which are preferred are polymers containing vinylamine units and polyethyleneimines. Examples for this are:

Vinylamine homopolymers, 10 to 100% hydrolyzed polyvinylformamides, partially or completely, preferably 85-95%, hydrolyzed copolymers of vinylformamide and vinyl acetate, vinyl alcohol, vinylpyrrolidone or acrylamide, each with K values from 50 to 135, in particular 80 to 95 and

Polyethyleneimines, crosslinked polyethyleneimines or amidated polyethyleneimines, each of which has a molecular weight of 500 to 3,000,000. The polymer content of the aqueous solution is, for example, 1 to 60, preferably 2 to 15 and usually 5 to 10% by weight.

Paper, cardboard and cardboard are usually produced by dewatering a slurry of cellulose fibers. The use of kraft pulp is particularly preferred. The use of TMP and CTMP is also of particular interest. The pH of the cellulose fiber slurry is, for example, 4 to 8, preferably 6 to 8. The paper stock can be dewatered discontinuously or continuously on a paper machine. The order of addition of cationic polymer, bulk sizing agent and retention agent can be chosen arbitrarily. However, one is preferred

Procedure in which the cationic polymer, preferably polyvinylamine, and then at least one reactive sizing agent such as alkyl ketene dimer, alkyl or alkenyl succinic anhydride or a mixture of these sizing agents are first added to the aqueous cellulose fiber slurry. Then at least one retention aid is dosed. According to another embodiment of the method according to the invention, at least one mass sizing agent is metered in first, then the retention agent and finally the cationic polymer. After dewatering the paper stock and drying the paper product, mass-sized paper products such as paper, cardboard or cardboard are obtained with a basis weight of 20 to 400 g / m2, preferably 40 to 220 g / m2.

When using alkyldiketene dispersions as sizing agents for paper, the full sizing effect is known to develop only after the sized papers have been stored for a long time. Surprisingly, the polymers containing vinylamine units to be used according to the invention act as promoters in the sizing of paper with aqueous, anionic alkyldiketene dispersions. When combinations of aqueous, anionic alkyldiketene dispersions and polyvinylamines are used as the mass sizing agent for paper, the sizing is rapidly formed so that the papers sized with this combination can be processed further immediately after their production, e.g. you can coat or print them with paper coating slips without long storage.

The paper stock is additionally dewatered in the presence of a retention agent. In addition to anionic retention aids or nonionic retention aids such as polyacrylamides, cationic polymers are preferably used as retention aids and as drainage aids. This leads to a significant improvement in the runnability of the paper machines. All commercially available products for this purpose can be used as cationic retention agents. These are, for example, cationic polyacrylamides, polydiallyldimethylammonyl and chloride, high molecular weight polyvinylamines, polyethyleneimines, polyamines with a molecular weight of more than 50,000, modified polyamines which are grafted and crosslinked with ethyleneimine, polyetheramides, polyvinylimidazoles, polyvinylpyrrolidines, polyvinylimidazolines , Polyvinyltetrahydropyrins, poly (dialkylaminoalkyl vinyl ethers), poly (dialkylaminoalkyl (meth) acrylates) in protonated or in quaternized form, and also polyamidoamines from a dicarboxylic acid such as adipic acid and polyalkylene polyamines such as diethylene triamine amine, which are grafted with ethyleneimine and according to the teaching of polyethylene glycol according to polyethylene glycol DE-B-24 34 816 are crosslinked or to polyamidoamines which have been reacted with epichlorohydrin to form water-soluble condensation products and to copolymers of acrylamide or methacrylamide and dialkylaminoethyl acrylates or methacrylates, for example ise copolymers of acrylamide and dimethylaminoethyl acrylate in the form of the salt with hydrochloric acid or in the form quaternized with methyl chloride. Other suitable retention agents are so-called microparticle systems made from cationic polymers such as cationic starch and finely divided silica or from cationic polymers such as cationic polyacrylamide and bentonite.

The cationic polymers that are used as retention agents have, for example, K values according to Fikentscher of at least 140 (determined in 5% aqueous saline solution at a polymer concentration of 0.5% by weight, a temperature of 25 ° C. and a pH of 7). They are preferably used in amounts of 0.01 to 0.3% by weight, based on dry cellulose fibers.

Unless the context indicates otherwise, the percentages in the examples mean percent by weight. The K values were determined according to H. Fikentscher, Cellulose-Chemie, Vol. 13, 58-64 and 71-74 (1932) in 5% aqueous saline solution in a

Temperature of 25 ° C and a pH of 7 at a polymer concentration of 0.5 wt .-% determined. The molecular weights Mw of the polymers were measured by light scattering.

Examples

Ink flotation time

The ink floating time (measured in minutes) is the time it takes a test ink according to DIN 53126 to reach 50% through a test sheet.

Cobb value

Determination was carried out in accordance with DIN 53 132 by storing the paper sheets in water for a period of 60 seconds. The water absorption is given in g / m.2.

Polyvinylamine A

Cationic polymer obtained by hydrolysis of 90-K poly-N-vinylformamide with a degree of hydrolysis of 95 mol% (polymer containing 95 mol% vinylamine units and 5 mol% vinylformamide units) ,

Anionic bulk sizing agent A

Aqueous dispersion of a mixture of palmityldiketene and stearyldiketene, prepared according to Example 1 of WO-A-00/23651 with the sodium salt of the condensation product of naphthalene sulfone acid with formaldehyde in a molar ratio of 1: 0.8 and a molecular weight Mw of 7000 as an anionic dispersant.

example 1

To a paper stock with a consistency of 8 g / 1 made from a completely bleached mixture of 70% pine and 30% birch sulfate pulp with a freeness of 35 ° (Schopper-Riegel), 0 was added, each based on a dry cellulose fiber mixture , 08% of the anionic sizing agent A, 0.04% of a commercially available cationic polyacrylamide (Polymin® KE 2020) and 0.1% polyvinylamine A. The pH of the mixture was adjusted to 7.0. The mixture was then processed on a Rapid-Köthen sheet former to form a sheet with a basis weight of 100 g / m 2. The sheet was then dried on a steam-heated drying cylinder at a temperature of 90 ° C to a water content of 6%. After drying, the Cobb value and the ink floating time of the sheet were determined. The results are shown in the table.

Example 2

Example 1 was repeated with the only exception that the amount of polyvinylamine A was increased to 0.2%. The results obtained are shown in the table.

Example 3

Example 1 was repeated with the only exception that the amount of polyvinylamine A was increased to 0.6%. The results obtained are shown in the table.

Comparative Example 1

To a paper stock with a consistency of 8 g / 1 made from a completely bleached mixture of 70% pine and 30% birch sulfate pulp with a freeness of 35 ° (Schopper-Riegel), 0 was added, each based on a dry cellulose fiber mixture , 08% of a commercial aqueous dispersion of an alkyldiketene dimer stabilized with cationic starch (Basoplast® 2030 LC) and 0.04% of a cationic polyacrylamide (Polymin® KE 2020). The pH of the mixture was adjusted to 7.0. The mixture was then processed on a Rapid-Koethen sheet former to form a sheet with a basis weight of 100 g / m 2. The sheet was then dried on a steam-heated drying cylinder at a temperature of 90 ° C to a water content of 6%. After drying the Cobb value and determines the ink floating time of the sheet. The results are shown in the table.

Comparative Example 2

Comparative example 1 was repeated with the only exception that after the addition of Polymin® KE 2020 commercial cationic starch (Solvitose®BKN) was added in an amount of 0.6%. The results obtained are shown in the table.

Comparative Example 3

Comparative Example 1 was repeated with the only exception that after metering in Polymin®KE 2020, polyvinylamine A was metered in in an amount of 0.2% to the paper stock. The results are shown in the table.

table

Claims

claims

1. Process for mass sizing paper, cardboard and cardboard by adding anionically adjusted aqueous dispersions of

Reactive sizing agents and at least one retention agent for an aqueous slurry of cellulose fibers and dewatering of the paper stock, characterized in that at least one cationic polymer is additionally added to the aqueous slurry of cellulose fibers.

2. The method according to claim 1, characterized in that the cationic polymers used are vinylamine-containing polymers, vinylguanidine-containing polymers, polyethylenimines, polyamidoamines grafted with ethyleneimine and / or polydiallyldimethylammonium chlorides.

3. The method according to claim 1 or 2, characterized in that the cationic polymers used are vinylamine-containing polymers and or polyethyleneimines.

4. The method according to any one of claims 1 to 3, characterized in that 10 to as cationic polymers

100 mol% of hydrolyzed homo- or copolymers of N-vinylformamide are used.

5. The method according to any one of claims 1 to 4, characterized in that polyvinylamines are used as cationic polymers.

6. The method according to any one of claims 1 to 5, characterized in that the sizing agent is Cχ - to C ₀ -Alkylketen- dimers, C ₅ - to C ₂₂ -alkyl- or C ₅ - to C -alkenylsuccinic acid anhydrides and / or Cχ - C ₃₆ uses alkyl isocyanates.

7. The method according to any one of claims 1 to 6, characterized in that one uses C ₄ -bis cis-alkyl ketene dimers together with polymers containing vinylamine units.

8. The method according to any one of claims 1 to 7, characterized in that first metered at least one cationic polymer and then the anionically adjusted aqueous dispersion of a reactive sizing agent for the aqueous slurry of cellulose fibers.

9. The method according to any one of claims 1 to 7, characterized in that first metered an anionic aqueous dispersion of a reactive sizing agent for aqueous slurry of cellulose fibers and then a cationic polymer.

10. Use of cationic polymers from the group of polymers containing vinylamine units, polymers containing vinylguanidine units, polyethyleneimines, polyamidoamines grafted with ethyleneimine and / or polydiallyldimethylammonium chlorides as fixatives and promoters for anionically adjusted aqueous dispersions of a reactive sizing agent from paper in the case of the paste , Cardboard and cardboard.