DE102005029010A1 - Production of paper, paperboard and cardboard comprises adding of polymer containing vinylamine units and an anionic polymer compound to a paper material, draining the paper material and drying the paper products - Google Patents

Abstract

Production of paper, paperboard and cardboard comprises adding a polymer containing vinylamine units and an anionic polymer compound to a paper material, draining the paper material and drying the paper products; where the anionic polymer compound is a copolymer obtained by the copolymerization of N-vinylcarboxylic acid amide compound (a), monoethylenically unsaturated monomer (b) containing acid groups, optionally: other monoethylenically unsaturated monomer (c) and compounds (d) comprising at least two ethylenically unsaturated double bonds in the molecule. Production of paper, paperboard and cardboard comprises adding a polymer containing vinylamine units and an anionic polymer compound to a paper material, draining the paper material and drying the paper products; where the anionic polymer compound is a copolymer obtained by the copolymerization of N-vinylcarboxylic acid amide compound (I) of formula (CH 2=CH-N(-R 2>)(-CO-R 1>)), at least a monoethylenically unsaturated monomer (b) containing acid groups and/or its alkali metal, alkaline earth metal or ammonium salts, optionally other monoethylenically unsaturated monomer (c), and optionally compounds (d) comprising at least two ethylenically unsaturated double bonds in the molecule. R 1>, R 2>H or 1-6C alkyl.

Description

The The invention relates to a process for the production of paper, cardboard and cardboard by separate addition of a Vinylamineinheiten containing Polymer and a polymeric anionic compound to a pulp, Drain of the stock and drying the paper products. The invention also relates to the use of a Vinylamineinheiten containing Polymer and a polymeric anionic compound as a dry strength agent and / or as a retention and drainage agent in a process for the production of paper, board and cardboard by separate addition to a pulp, dewatering of the stock and drying the paper products.

to Production of paper with high dry strength is known on the surface aqueous solutions of cooked starch or starch diluted in already dried paper of synthetic polymers, each as a dry strength agent Act. The amounts of dry strength agent are in the Usually 0.1 to 6 wt .-%, based on dry paper. As the dry strength agent including the strength in an aqueous diluted solution be applied - in general amounts the polymer or starch concentration the aqueous Preparation solution between 1 and 10 wt .-% - is in the subsequent drying process a considerable To evaporate amount of water. The drying step is therefore very energy intensive. The capacity the usual Dryers on paper machines but is not in many cases so big that at the maximum possible Production speed of the machine could drive. The production speed the paper machine must rather be withdrawn so that the Paper to a sufficient extent is dried.

Out The CA patent 1 110 019 is a process for the production of paper known with high dry strength, in which one to the pulp first a water-soluble cationic polymer, e.g. As polyethyleneimine, admits and after a water-soluble anionic polymer, e.g. a hydrolyzed polyacrylamide, and the Debris drained on the paper machine under sheet formation. The anionic polymers contain up to 30 mol% of copolymerized acrylic acid.

From DE-A 35 06 832 a process for the production of paper with high dry strength is known, in which one adds to the pulp first a water-soluble cationic polymer and then a water-soluble anionic polymer. Suitable anionic polymers are, for example, homopolymers or copolymers of ethylenically unsaturated C ₃ -C ₅ -carboxylic acids. The Copo lymerisate contain at least 35 wt .-% of an ethylenically unsaturated C ₃ -C ₅ carboxylic acid (eg acrylic acid) in copolymerized form. As cationic polymers in the examples polyethyleneimine, polyvinylamine, polydiallyldimethylammonium chloride and epichlorohydrin crosslinked condensation products of adipic acid and diethylenetriamine are described. The use of partially hydrolyzed homo- and copolymers of N-vinylformamide has also been considered. The degree of hydrolysis of the N-vinylformamide polymers is at least 30 mol% and is preferably 50 to 100 mol%.

The JP-A 1999-140787 relates to a process for producing corrugated board, to improve the strength properties of a paper product to the pulp 0.05 to 0.5 wt .-%, based on dry pulp, a polyvinylamine obtained by hydrolysis of polyvinylformamide with a degree of hydrolysis of 25 to 100%, in combination with an anionic polyacrylamide admits the pulp then drained and dry.

Out WO 03/052206 is a paper product with improved strength properties known to be available is that one on the surface a paper product, a polyvinylamine and a polymeric anionic A compound that forms a polyelectrolyte complex with polyvinylamine can, or a polymeric compound with aldehyde functions such as aldehyde groups containing polysaccharides. Not only is there an improvement the dry and wet strength of the paper, but observed also a sizing effect of the treatment agent.

Out WO 04/061235 is a process for the production of paper, in particular Tissue, with particularly high wet and / or dry strengths, in which one to the pulp first a water-soluble cationic Polymer admits that contains at least 1.5 meq / g of polymer to primary amino functionalities and a Having molecular weight of at least 10,000 daltons. Especially in this case, partially and fully hydrolyzed homopolymers are emphasized of N-vinylformamide. Subsequently becomes a water soluble anionic polymer added that anionic and / or aldehydic Contains groups. The advantage of this method is above all the variability of the described Two-component systems with regard to different paper properties, including wet and dry strength, exposed.

Out EP-A 438 744 is the use of copolymers of, for example Nvinylformamide and acrylic acid, methacrylic acid and / or maleic acid with a K value of 8 to 50 (determined according to H. Fikentscher in 1 % aqueous solution at pH 7 and 25 ° C) and the resulting by partial or complete elimination of Formylgrup pen from the copolymerized vinylformamide with formation of vinylamine units available Polymers as scale inhibitors in water-bearing systems such as boilers or pipes, known.

Besides that is discloses that copolymers obtained by copolymerizing N-vinylcarboxamides monoethylenically unsaturated carboxylic acids and optionally other ethylenically unsaturated monomers and subsequent hydrolysis the vinylcarboxylic acid units contained in the copolymers to the corresponding Amine or ammonium units available are used in papermaking as an additive to the pulp to increase the drainage rate and the retention as well as the dry and wet strength of the paper can use, cf. EP-B 672 212.

The Use of oppositely charged polymers as retention and dehydrating agents in the papermaking process is known from the literature.

EP-B 227 465 describes a method for producing a filled paper, in which the fiber suspension and the filler suspension are separated from each other with a synthetic flocculant of the same charge be treated. Subsequently becomes the filler suspension treated with a polymer of opposite charge before the Suspension are mixed together and dehydrate by Drying a paper product is made.

From the US 3,617,568 For example, a method of flocculating charged particles in a colloidal system is known, in which first a polymer of molecular weight <30,000 and in a second step a polymer of opposite charge and molecular weight between 100,000 and 10,000,000 is used.

The DE-C 44 36 317 describes a method for improving the retention of mineral fillers and Cellulose fibers by adding a high molecular weight anionic polymer flocculant, which, for example, an acrylic or methacrylic acid polymer can be, and subsequent Addition of a high molecular weight cationic copolymer flocculant. The latter is made up of uncharged monomers such as acrylamide and methacrylamide with a cationically charged monomer such as dimethylaminoethyl acrylate or diallyldimethylammoniumchloride.

The use of high molecular weight cationic acrylamides as flocculants in combination with anionic polymeric flocculants is also out US 5,098,520 known.

A similar process, in which a cationic copolymer of acrylamide and diallyldimethylammonium chloride is used as a flocculating agent in combination with an anionic polymer, is also disclosed in US Pat US 5,266,164 described.

Of the present invention is based on the object another Process for the production of paper with high dry strength and as possible to provide low wet strength. However, it should across from the previously known methods the increase in dry strength, especially in packaging papers (e.g., testliner), even further be improved. About that In addition, the wet strength or the ratio of wet to dry strength be further minimized. Furthermore, the retention and drainage be improved, in particular by increased retention of fine and fillers and shortened drainage times with simultaneous constancy of the retention and drainage effect.

• (a) mindestens eines N-Vinylcarbonsäureamids der Formel
  
  in der R¹, R² = H oder C₁- bis C₆-Alkyl bedeuten,
• (b) mindestens eines Säuregruppen enthaltenden monoethylenisch ungesättigten Monomeren und/oder deren Alkalimetall-, Erdalkalimetall- oder Ammoniumsalzen,
• (c) gegebenenfalls anderen monoethylenisch ungesättigten Monomeren und
• (d) gegebenenfalls Verbindungen, die mindestens zwei ethylenisch ungesättigte Doppelbindungen im Molekül aufweisen.

The object is achieved according to the invention by a process for the production of paper, paperboard and cardboard by separate addition of a vinylamine units containing polymer and a polymeric anionic compound to a pulp, dewatering of the pulp and drying of the paper products, if at least one copolymer is used as the polymeric anionic compound , which is obtainable by copolymerizing

• (a) at least one N-vinylcarboxamide of the formula
  
  in which R ¹ , R ² = H or C ₁ - to C ₆ -alkyl,
• (b) at least one acid group-containing monoethylenically unsaturated monomer and / or their alkali metal, alkaline earth metal or ammonium salts,
• (c) optionally other monoethylenically unsaturated monomers and
• (D) optionally compounds which have at least two ethylenically unsaturated double bonds in the molecule.

• (a) N-Vinylformamid,
• (b) Acrylsäure, Methacrylsäure und/oder deren Alkali- oder Ammoniumsalzen und
• (c) gegebenenfalls anderen monoethylenisch ungesättigten Monomeren.

Preferably used as the polymeric anionic compound is a copolymer obtainable by copolymerizing

• (a) N-vinylformamide,
• (b) acrylic acid, methacrylic acid and / or their alkali or ammonium salts and
• (c) optionally other monoethylenically unsaturated monomers.

• (a) 10 bis 95 Mol-% Einheiten der Formel I,
• (b) 5 bis 90 Mol-% Einheiten einer monoethylenisch ungesättigten Carbonsäure mit 3 bis 8 C-Atomen im Molekül und/oder deren Alkalimetall-, Erdalkalimetall- oder Ammoniumsalze und
• (c) 0 bis 30 Mol-% Einheiten mindestens eines anderen monoethylenisch ungesättigten Monomeren.

The polymeric anionic compound contains, for example

• (a) 10 to 95 mol% of units of the formula I,
• (B) 5 to 90 mol% of units of a monoethylenically unsaturated carboxylic acid having 3 to 8 carbon atoms in the molecule and / or their alkali metal, alkaline earth metal or ammonium salts and
• (c) 0 to 30 mol% of units of at least one other monoethylenically unsaturated monomer.

• (a) 10 bis 95 Mol-% Einheiten der Formel I,
• (b) 5 bis 90 Mol-% Einheiten eines Säuregruppen enthaltenden monoethylenisch ungesättigten Monomeren und/oder deren Alkalimetall-, Erdalkalimetall- oder Ammoniumsalzen,
• (c) 0 bis 30 Mol-% Einheiten mindestens eines anderen monoethylenisch ungesättigten Monomeren und
• (d) 0 bis 2 Mol-%, vorzugsweise 0,001 bis 1 Mol-% mindestens einer Verbindung mit mindestens zwei ethylenisch ungesättigten Doppelbindungen einpolymerisiert.

These compounds may be modified so that they additionally contain at least one compound having at least two ethylenically unsaturated double bonds copolymerized in the molecule. When the monomers (a) and (b) or (a), (b) and (c) are copolymerized in the presence of such a compound, branched copolymers are obtained. The proportions and reaction conditions are to be chosen so that water-soluble polymers are still obtained. Under certain circumstances it may be necessary to use polymerization regulators. All known regulators can be used, such as, for example, thiols, sec. Alcohols, sulfites, phosphites, hypophosphites, thioacids, aldehydes, etc. (further details can be found, for example, in EP-A 438 744, page 5, lines 7-12). The branched copolymers contain, for example

• (a) 10 to 95 mol% of units of the formula I,
• (b) 5 to 90 mol% of units of an acid group-containing monoethylenically unsaturated monomer and / or their alkali metal, alkaline earth metal or ammonium salts,
• (c) 0 to 30 mol% of units of at least one other monoethylenically unsaturated monomer and
• (D) 0 to 2 mol%, preferably 0.001 to 1 mol% of at least one compound copolymerized with at least two ethylenically unsaturated double bonds.

Examples for monomers of group (a) are N-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N-vinyl-N-ethyl acetamide, N-vinyl-N-methylpropionamide and N-vinylpropionamide. The monomers the group (a) can alone or in mixture in the copolymerization with the monomers used by other groups.

When Monomers of group (b) are in particular monoethylenically unsaturated carboxylic acids 3 to 8 carbon atoms and the water-soluble salts of these carboxylic acids in Consideration. This group of monomers includes, for example, acrylic acid, methacrylic acid, dimethacrylic acid, ethacrylic acid, maleic acid, fumaric acid, itoconic acid, mesaconic acid, citraconic acid, methylenemalonic acid, allylacetic acid, vinylacetic acid and Crotonic. Suitable monomers of group (b) are also sulfo-containing monomers like vinylsulfonic acid, Acrylamido-2-methylpropane and styrenesulfonic acid and vinylphosphonic acid. The monomers of this group can alone or mixed with each other, partially or completely neutralized Form can be used in the copolymerization. For neutralization For example, using alkali metal or alkaline earth metal bases, Ammonia, amines and / or alkanolamines. Examples of this are caustic soda, Potassium hydroxide, soda, potash, sodium bicarbonate, magnesium oxide, Calcium hydroxide, calcium oxide, triethanolamine, ethanolamine, morpholine, Diethylenetriamine or tetraethylenepentamine. The monomers of the group (b) are preferably partially neutralized in the copolymerization Form used.

The copolymers may optionally contain monomers of group (c) in copolymerized form, for example esters of ethylenically unsaturated C _{3 to} C ₅ carboxylic acids such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, isobutyl methacrylate, methyl methacrylate, ethyl methacrylate and vinyl esters such as vinyl acetate or Vinyl propionate, or other monomers such as N-vinylpyrrolidone, N-vinylimidazole, acrylamide and / or methacrylamide.

A further modification of the copolymers is possible by that in the Copolymerisa tion monomers (d) containing at least two double bonds in the molecule, eg Methlenbisacrylamid, glycol diacrylate, glycol dimethacrylate, Gylcerintriacrylat, triallylamine, Pentaerythrittriallylether, at least twice with acrylic acid and / or methacrylic acid esterified polyalkylene glycols or polyols such as pentaerythritol, Sobit or glucose. If at least one monomer of group (d) is used in the copolymerization, the amounts used are up to 2 mol%, for example 0.001 to 1 mol%.

The Copolymerization of the monomers takes place in a known manner in the presence of radical polymerization initiators and optionally in the presence of polymerization regulators, cf. EP-B 672 212, page 4, lines 13-37 or EP-A 438 744, page 2, line 26 to page 8, Line 18.

• (a) mindestens einem N-Vinylcarbonsäureamid der Formel
  
  in der R¹, R² = H oder C₁- bis C₆-Alkyl bedeuten,
• (b) mindestens einer monoethylenisch ungesättigten Carbonsäure mit 3 bis 8 C-Atomen im Molekül und/oder deren Alkalimetall-, Erdalkalimetall- oder Ammoniumsalzen,
• (c) gegebenenfalls anderen monoethylenisch ungesättigten Monomeren und
• (d) gegebenenfalls Verbindungen, die mindestens zwei ethylenisch ungesättigte Doppelbindungen im Molekül aufweisen,

und anschließende teilweise Abspaltung von Gruppen -CO-R¹ aus den in das Copolymerisat einpolymerisierten Monomeren der Formel I unter Bildung von Aminogruppen, wobei der Gehalt an Aminogruppen im Copolymerisat mindestens 5 Mol-% unter dem Gehalt an einpolymerisierten Säuregruppen der Monomere (b) beträgt. Bei der Hydrolyse von N-Vinylcarbonsäureamidpolymeren entstehen in einer sekundären Reaktion Amidineinheiten, indem Vinylamineinheiten mit einer benachbarten Vinylformamideinheit reagieren. Im Folgenden bedeutet die Angabe von Vinylamineinheiten in den amphoteren Copolymerisaten immer die Summe aus Vinylamin- und Amidineinheiten.Suitable polymeric anionic compounds are also amphoteric copolymers obtainable by copolymerizing

• (a) at least one N-vinylcarboxamide of the formula
  
  in which R ¹ , R ² = H or C ₁ - to C ₆ -alkyl,
• (b) at least one monoethylenically unsaturated carboxylic acid having 3 to 8 C atoms in the molecule and / or their alkali metal, alkaline earth metal or ammonium salts,
• (c) optionally other monoethylenically unsaturated monomers and
• (d) optionally compounds which have at least two ethylenically unsaturated double bonds in the molecule,

and subsequent partial cleavage of groups -CO-R ¹ from the copolymerized in the copolymer monomers of formula I to form amino groups, wherein the content of amino groups in the copolymer at least 5 mol% below the content of copolymerized acid groups of the monomers (b) , In the hydrolysis of N-vinylcarboxamide polymers, amidine units are formed in a secondary reaction by reacting vinylamine units with an adjacent vinylformamide unit. In the following, the indication of vinylamine units in the amphoteric copolymers always means the sum of vinylamine and amidine units.

• (a) 10 bis 95 Mol-% Einheiten der Formel I,
• (b) 5 bis 90 Mol-% Einheiten eines Säuregruppen enthaltenden monoethylenisch ungesättigten Monomeren und/oder deren Alkalimetall-, Erdalkalimetall- oder Ammoniumsalzen,
• (c) 0 bis 30 Mol-% Einheiten mindestens eines anderen monoethylenisch ungesättigten Monomeren,
• (d) 0 bis 2 Mol-% Einheiten mindestens einer Verbindung, die mindestens zwei ethylenisch ungesättigte Doppelbindungen in Molekül aufweist, und
• (e) 0 bis 42 Mol-% Vinylamineinheiten

einpolymerisiert enthält, wobei der Gehalt an Aminogruppen im Copolymerisat mindestens 5 Mol-% unter dem Gehalt an einpolymerisierten Säuregruppen enthaltenden Monomeren (b) beträgt.The amphoteric compounds thus obtained contain, for example

• (a) 10 to 95 mol% of units of the formula I,
• (b) 5 to 90 mol% of units of an acid group-containing monoethylenically unsaturated monomer and / or their alkali metal, alkaline earth metal or ammonium salts,
• (c) 0 to 30 mol% of units of at least one other monoethylenically unsaturated monomer,
• (d) 0 to 2 mol% of units of at least one compound having at least two ethylenically unsaturated double bonds in molecule, and
• (e) 0 to 42 mole percent vinylamine units

contains copolymerized, wherein the content of amino groups in the copolymer is at least 5 mol% below the content of copolymerized acid group-containing monomers (b).

The Hydrolysis of anionic copolymers can be carried out in the presence of acids or Bases or be carried out enzymatically. In the hydrolysis with acids are those from the Vinylcarbonsäureamideinheiten resulting vinylamine groups in salt form. The hydrolysis of Vinylcarbonsäureamidcopolymerisaten is in EP-A 438 744, page 8, line 20 to page 10, line 3, described in detail. The statements made there apply accordingly for the preparation of the invention to be used amphoteric polymers.

• (a) 50 bis 90 Mol-% N-Vinylformamid,
• (b) 10 bis 50 Mol-% Acrylsäure, Methacrylsäure und/oder deren Alkali- oder Ammoniumsalze und
• (c) 0 bis 30 Mol-% mindestens eines anderen monoethylenisch ungesättigten Monomeren einpolymerisiert enthält.

As the polymeric anionic compound is preferably used a copolymer which

• (a) 50 to 90 mol% N-vinylformamide,
• (B) 10 to 50 mol% of acrylic acid, methacrylic acid and / or their alkali or ammonium salts and
• (C) 0 to 30 mol% of at least one other monoethylenically unsaturated monomer in copolymerized form.

The average molecular weights M _{W of} the anionic or amphoteric polymers, for example 30,000 daltons to 10 million daltons, preferably 100,000 daltons to 1 million daltons. These polymers have, for example, K values (determined according to H. Fikentscher in 5% aqueous saline solution at pH 7, a Po lymer concentration of 0.5 wt .-% and a temperature of 25 ° C) in the range of 20 to 250, preferably 50 to 150.

In the process according to the invention, a polymeric cationic component which is exclusively polymer containing vinylamine units is first added to the paper stock. For this purpose, all polymers are suitable, for example, in the cited in the prior art WO 04/061235, page 12, line 28 to page 13, line 21 and in 1 are indicated. The molar masses M _{w of} the polymers containing vinylamine units is, for example, 1000 to 5 million and is usually in the range from 5,000 to 500,000, preferably 40,000 daltons to 400,000 daltons.

in der R¹, R² = H oder C₁- bis C₆-Alkyl bedeuten,
und anschließende teilweise oder vollständige Abspaltung der Gruppen -CO-R¹ aus den in das Polymerisat einpolymerisierten Einheiten der Monomeren I unter Bildung von Aminogruppen. Wie oben bereits dargelegt, können sich in einer sekundären Reaktion aus Vinylamineinheiten und benachbarten Vinylformamideinheiten Amidineinheiten bilden. Auch für die hier beschriebenen kationischen Polymeren umfasst die Angabe von Vinylamineinheiten die Summe aus Vinylamin- und Amidineinheiten im Polymeren. Als Vinylamineinheiten enthaltendes Polymer setzt man beispielsweise ein zu mindestens 10 Mol-% hydrolysiertes Homopolymerisat von N-Vinylformamid ein. Polyvinylamin und/oder zu mindestens 50 Mol-% hydrolysierte Homopolymerisate des N-Vinylformamids werden bei dem erfindungsgemäßen Verfahren bevorzugt als kationische Komponente eingesetzt.The other group of polymers, namely polymers containing vinylamine units, are obtainable, for example, by polymerizing at least one monomer of the formula

in which R ¹ , R ² = H or C ₁ - to C ₆ -alkyl,
and subsequent partial or complete cleavage of the groups -CO-R ¹ from the units of the monomers I copolymerized in the polymer to form amino groups. As stated above, in a secondary reaction, amidine units can form from vinylamine units and adjacent vinylformamide units. Also for the cationic polymers described herein, the indication of vinylamine units comprises the sum of vinylamine and amidine units in the polymer. As polymer containing vinylamine units, for example, a homopolymer of N-vinylformamide hydrolyzed to at least 10 mol% is used. Polyvinylamine and / or at least 50 mol% of hydrolyzed homopolymers of N-vinylformamide are preferably used in the inventive method as a cationic component.

• (a) mindestens eines N-Vinylcarbonsäureamids der Formel
  
  in der R¹, R² = H oder C₁- bis C₆-Alkyl bedeuten,
• (b) mindestens eines Säuregruppen enthaltenden monoethylenisch ungesättigten Monomeren und/oder deren Alkalimetall-, Erdalkalimetall- oder Ammoniumsalalzen,
• (c) gegebenenfalls anderen monoethylenisch ungesättigten Monomeren und
• (d) gegebenenfalls Verbindungen, die mindestens zwei ethylenisch ungesättigte Doppelbindungen im Molekül aufweisen

und anschließende teilweise oder vollständige Abspaltung der Gruppen -CO-R¹ aus den in das Polymerisat einpolymerisierten Einheiten der Monomeren I unter Bildung von Aminogruppen, wobei der Anteil der Aminogruppen im Copolymerisat um mindestens 10 Mol-% größer ist als der Anteil der Einheiten an Säuregruppen enthaltenden monoethylenisch ungesättigten Monomeren.In the process according to the invention, it is also possible to use amphoteric copolymers as the cationic component, provided that they have at least 10 mol% more cationic than anionic groups. Such amphoteric polymers are obtainable, for example, by copolymerization

• (a) at least one N-vinylcarboxamide of the formula
  
  in which R ¹ , R ² = H or C ₁ - to C ₆ -alkyl,
• (b) at least one monoethylenically unsaturated monomer containing acid groups and / or their alkali metal, alkaline earth metal or ammonium salts,
• (c) optionally other monoethylenically unsaturated monomers and
• (D) optionally compounds which have at least two ethylenically unsaturated double bonds in the molecule

and subsequent partial or complete cleavage of the groups -CO-R ¹ from the polymerized into the polymer units of the monomers I to form amino groups, wherein the proportion of amino groups in the copolymer by at least 10 mol% greater than the proportion of units of acid groups containing monoethylenically unsaturated monomers.

These Polymers are accessible by the same method as those described above amphoteric polymers according to the invention as anionic component but only the ratio of cationic to anionic groups different, so that now cationic Receives polymers. Contains this group of polymers for example, up to a maximum of 35 mol%, preferably up to a maximum of 10 mol% at least one acid group containing monomers of group (b).

Suitable pulps for the production of the pulps are all qualities customary therefor, for example wood pulp, bleached and unbleached pulp and pulps from all annual plants. Wood pulp includes, for example, groundwood, thermomechanical pulp (TMP), chemo-thermo-mechanical pulp (CTMP), pressure groundwood, semi-pulp, high yield pulp, and refiner mechanical pulp (RMP). As pulp, for example, sulphate, sulphite and soda pulps come into consideration. Preferably, unbleached pulp, also referred to as unbleached kraft pulp, is used. Suitable year old Plants for the production of paper materials are for example rice, wheat, sugarcane and kenaf. Waste paper is usually used to make the pulps, either alone or in admixture with other pulps, or starting from pulp blends of a primary pulp and recycled broke pulp, eg bleached pine sulfate mixed with recycled coated pulp. The process according to the invention has particular significance for the production of paper and cardboard from waste paper, because it significantly increases the strength properties of the recycled fibers.

Of the pH of the stock suspension is, for example, in the range from 4.5 to 8, most at 6 to 7.5. For adjusting the pH you can, for example, an acid like sulfuric acid or use aluminum sulphate.

The Polymers containing vinylamine units, i. the cationic component the polymer to be metered to the paper stock, in the inventive method preferably added to thick matter or to a thin material. The access point preferably lies after a Stoffbütte, but can also between a shearing stage and a screen or after. The anionic Component usually only after the addition of the cationic component added to the pulp, but also simultaneously, but separately be metered from the cationic component to the pulp. Furthermore, it is also possible first to add the anionic and subsequently the cationic component. The vinylamine units containing polymer and the polymeric anionic Compound, for example, each in an amount of 0.1 to 2.0 wt .-%, preferably 0.3 to 1 wt .-%, based on dry Paper stock used. The ratio of vinylamine units containing polymer to polymeric anionic compound is, for example 5: 1 to 1: 5 and is preferably in the range of 2: 1 until 12.

To the method according to the invention are a vinylamine units containing polymer and a polymeric anionic compound to the paper stock as a dry strength agent and / or retention and drainage agents added separately.

Therefore is the use of a polymer containing vinylamine units and a polymeric anionic compound as a dry setting agent and / or retention and drainage agents in the method according to the invention also subject of this invention.

To the method according to the invention receives one paper products opposite the prior art processes have a higher dry strength level while having low wet strength. Furthermore are those according to the inventive method produced paper products with increased retention and shortened drainage times accessible in comparison to the prior art. The paper structure and paper properties are not affected.

The parts given in the following examples are parts by weight, the percentages are based on the weight of the substances. Of the K value of the polymers was according to Fikentscher, Cellulose Chemistry, Volume 13, 58-64 and 71-74 (1932) at a temperature of 20 ° C in 5 wt .-% aqueous Saline solutions at a pH of 7 and a polymer concentration of 0.5%. This means K = k × 1000.

For the individual Tests were performed in laboratory tests on sheets in a Rapid-Köthen laboratory sheet former. The dry tear length became according to DIN 53 112, sheet 1 and the wet breaking length according to DIN 53 112, Sheet 2 determined. The CMT value was determined according to DIN 53 143, the Dry burst pressure was determined according to DIN 53 141.

Examples

Out 100% mixed waste paper, a 0.5% aqueous pulp suspension was prepared. The pH of the suspension was 7.1, the freeness of the substance 50 ° Schopper-Riegler (° SR). The Stock suspension was then divided into 36 equal parts and into the Comparative Examples 1 to 26 and in Examples 27 to 36 below following conditions to leaves a basis weight processed of 120 gsm.

Comparative Example 1

Out The stock suspension described above was without further additives Sheet formed.

Comparative Examples 2-6 according to DE-A 35 06 832

To additional samples of the stock suspension described above were added, based on dry fiber, first those given in Table 1 Amounts of a polyvinylamine (PVAm 1) having a K value of 110 (prepared by hydrolysis of polyvinylformamide, degree of hydrolysis 95%) and after a residence time of 5 minutes, also given in Table 1 Quantities of a copolymer of 60% acrylic acid and 40% of acrylonitrile (copolymer 1) too. The copolymer was in the form of the sodium salt and had a K value of 130. After a contact time of 1 minute was the treated in this way each paper pulp under sheet formation dewatered.

Table 1

Comparative Examples 7-11 according to DE-A 35 06 832

To additional samples of the stock suspension described above were added, based on dry pulp, the quantities given in Table 2 a polyethyleneimine which in 10% aqueous solution has a viscosity of 30 mPas had. After an exposure time of 5 minutes, they added based on dry fiber, which are also shown in Table 2 Quantities of a copolymer of 50% acrylic acid and 50% of acrylonitrile (copolymer 2) too. The copolymer was in the form of the sodium salt and had a K value of 120. After a contact time of 1 minute was also treated in this way pulp under sheet formation dewatered.

Table 2

Comparative Examples 12-16 according to WO 04/061235

Other samples of the stock suspension as described above were added, based on dry fiber, of the amounts given in Table 3 of a polyvinylamine (PVAm 2) having a K-value of 90 (Catiofast ^® PR 8106 of BASF, made by hydrolysis of polyvinylformamide, degree of hydrolysis 90 %). After a residence time of 5 minutes, the amounts of a glyoxylated cationic polyacrylamide given also in Table 3 were (1 cationic copolymer, sold by Bayer AG under the name Parez ^® 631NC) was added to the paper stock suspension. After an exposure time of 1 minute, the stock treated in this manner was dewatered each time with sheet formation.

Table 3

Comparative Examples 17-21 according to WO 04/061235

To additional samples of the stock suspension described above were given in each case, based on dry pulp, the quantities indicated in Table 4 a polyvinylamine (PVAm 2) having a K value of 90 (prepared by hydrolysis of polyvinylformamide, degree of hydrolysis 90%). To a residence time of 5 minutes were each in Table 4 specified amounts of a copolymer of 80% acrylic acid and 20% acrylamide (copolymer 4) was added. The copolymer was in Form of the sodium salt before and had a K value of 120. After an exposure time of 1 minute was in each case in this way treated pulp dewatered with foliation.

Table 4

Comparative Examples 22-26 according to WO 04/061235

Other samples of the suspension described above, each of the quantities of a polyvinylamine (PVAm 2) shown in Table 5 were added, based on dry fiber, having a K value of 90 (Catiofast ^® PR 8106, produced by hydrolysis of polyvinylformamide, degree of hydrolysis 90% ) too. After a residence time of 5 minutes, the amounts indicated in Table 5 were then each an anionic glyoxylated copolymer of acrylic acid and acrylamide added (3 copolymer, sold under the name Parez ^® from Bayer AG). After an exposure time of 1 minute, the paper stock treated in this way was also dewatered with foliar formation.

Table 5

Examples 1-5 according to the invention

To additional samples of the stock suspension described above were added, based on dry fiber, in each case those specified in Table 6 Amounts of a polyvinylamine PVAm 3) with a K value of 90 (manufactured by hydrolysis of polyvinylformamide, degree of hydrolysis 50%). To a residence time of 5 minutes were then also each in Table 6 amounts of a copolymer of 30% acrylic acid and 70% vinylformamide (copolymer 4) was added. The copolymer was in the form of the sodium salt and had a K value of 90. After an exposure time of 1 minute was then also the in this treated paper pulp is dewatered with foliation. The Test results are summarized in Table 8.

Table 6

Examples 6-10 according to the invention

To additional samples of the stock suspension described above were added, based on dry fiber, in each case those indicated in Table 7 Amounts of a polyvinylamine (PVAm 4) with a K value of 90 (to 30%. hydrolyzed polyvinylformamide). After a stay of 5 minutes were then respectively the amounts shown in Table 7 a copolymer of 30% acrylic acid and 70% vinylformamide (Copolymer 4) was added. The copolymer was in the form of the sodium salt before and had a K value of 90. After an exposure time of 1 minute was then treated in this way each paper stock drained under foliation. The test results are summarized in Table 8.

Table 7

The in Comparative Examples 1-26 and Examples 1 to 10 respectively produced paper sheets were on dry and wet tear length, CMT value and dry burst pressure tested according to the methods given above. The Results of the tests, the at the respective formed leaves are given in Table 8 under Test Nos. 1 to 36. Test Nos. 27-36 are examples according to the invention.

X:

eingesetzte Menge an kationischer Komponente

Y:

eingesetzte Menge an anionischer Komponente

TRL:

Trockenreißlänge

NRL:

Naßreißlänge

Rel.

NRL: relative Naßreißlänge

The abbreviations used in Table 8 have the following meaning:

X:

used amount of cationic component

Y:

used amount of anionic component

TRL:

Dry breaking length

NRL:

wet breaking

Rel.

NRL: relative wet tear length

Table 8

As Table 8 shows, with the combinations according to the invention Test Nos. 27-36 opposite Comparative Test Nos. 1 to 26 the highest dry strength level achieved at the same time lowest wet strength. highlight is also the significantly lower level of wet strength when using a polyvinylamine with a relatively low degree of hydrolysis as a cationic component (see Examples 6 to 10).

Production of corrugated material from 100% recovered paper (department store waste)

A 100 g / m ² paper was produced over a period of about 18 hours with the same quality. Over this experimental period, the amounts of cationic and anionic components were slowly increased. As endpoints of the dosage, 1.35% of the cationic and 0.43% of the anionic substance were adjusted. The following changes were measured
Drainage time 300 ml from 75 seconds to 39 seconds
Haze 600 nm from 1.04 to 0.50
Total retention from 62.3% to 69.4%

Production of kraftliner quality from 100 % Waste paper

A 185 g / m ² paper was produced over a period of about 10 hours with the same quality. Over this experimental period, the amounts of cationic and anionic components were slowly increased. As end points of the dosage, 0.58% of the cationic and 0.6% of the anionic substance were adjusted. The following changes were measured:
Drainage time 400 ml from 66 seconds to 46 seconds
Total retention from 81.4% to 94.3%

in this connection the used retention agent was turned off.

Claims (16)

A process for the production of paper, paperboard and cardboard by separate addition of a vinylamine units containing polymer and a polymeric anionic compound to a pulp, dewatering of the pulp and drying of the paper products, characterized in that is used as the polymeric anionic compound at least one copolymer which is obtainable by copolymerizing (a) at least one N-vinylcarboxamide of the formula

in which R ^1, R ² = H or C ₁ - to C ₆ -alkyl, (b) at least one acid group-containing monoethylenically unsaturated monomers and / or their alkali metal, alkaline earth metal or ammonium salts thereof, (c) optionally other monoethylenically unsaturated monomers and (d) optionally, compounds having at least two ethylenically unsaturated double bonds in the molecule. Method according to claim 1, characterized in that in that a copolymer is used which is obtainable by copolymerization from (a) N-vinylformamide, (b) acrylic acid, methacrylic acid and / or their alkali metal or ammonium salts and (c) optionally others monoethylenically unsaturated Monomers. Method according to claim 1 or 2, characterized that the polymeric anionic compound (a) 10 to 95 mol% Units of the formula I, (b) 5 to 90 mole% units of one monoethylenically unsaturated carboxylic acid with 3 to 8 carbon atoms in the molecule and / or their alkali metal, alkaline earth metal or ammonium salts and (c) 0 to 30 mol% of units of at least one other monoethylenic unsaturated monomers contains polymerized. Method according to claim 3, characterized that the polymeric anionic compound (a) 10 to 95 mol% Units of the formula I, (b) 5 to 90 mole% units of a acid groups containing monoethylenically unsaturated monomers and / or their alkali metal, alkaline earth metal or ammonium salts, (C) 0 to 30 mol% of units of at least one other monoethylenic unsaturated Monomers and (d) 0 to 2 mol%, preferably 0.001 to 1 mol% Units of at least one compound having at least two ethylenic unsaturated double bonds contains polymerized. Process according to any one of Claims 1 to 4, characterized in that the polymeric anionic compound is obtainable by copolymerizing (a) at least one N-vinylcarboxamide of the formula

in which R ^1, R ² = H or C ₁ - to C ₆ -alkyl, (b) at least one monoethylenically unsaturated carboxylic acid having 3 to 8 carbon atoms in the molecule and / or the alkali metal, alkaline earth metal or ammonium salts thereof, ( c) optionally other monoethylenically unsaturated monomers and (D) optionally compounds which have at least two ethylenically unsaturated double bonds in the molecule, and subsequent partial cleavage of groups -CO-R ¹ from the monomers copolymerized in the copolymer of the formula I to form amino groups, wherein the content of amino groups in the copolymer at least 5 mol% below the content of copolymerized acid group-containing monomers (b). Method according to one of claims 1 to 5, characterized that the polymeric anionic compound (a) 10 to 95 mol% Units of the formula I, (b) 5 to 90 mole% units of a acid groups containing monoethylenically unsaturated monomers and / or their alkali metal, alkaline earth metal or ammonium salts, (C) 0 to 30 mol% of units of at least one other monoethylenic unsaturated monomers (d) 0 to 2 mol% of units of at least one compound, which has at least two ethylenically unsaturated double bonds in the molecule, and (e) 0 to 42 mole percent vinylamine units in copolymerized form contains the content of amino groups in the copolymer being at least 5 mol% below the content of copolymerized acid group-containing monomers (b) is. Method according to one of claims 1 to 6, characterized that the polymeric anionic compound (a) 50 to 90 mol% N-vinyl formamide, (B) 10 to 50 mol% of acrylic acid, methacrylic acid and / or their alkali metal or ammonium salts and (c) 0 to 30 mole% at least another monoethylenically unsaturated monomer in copolymerized form contains. Method according to one of claims 1 to 7, characterized in that one uses as vinylamine units containing polymer at least one compound obtainable by polymerizing at least one monomer

in which R ¹ , R ² = H or C ₁ - to C ₆ alkyl, and subsequent partial or complete cleavage of the groups -CO-R ¹ from the polymerized into the polymer units of the monomers I to form amino groups. the formula Method according to one of claims 1 to 8, characterized in that the polymer containing vinylamine units is at least 10 mol% hydrolyzed homopolymer of N-vinylformamide is used. Method according to one of claims 1 to 8, characterized in that the polymer containing vinylamine units is a Copoylmerisat used, which is obtainable by copolymerization (a) of at least one N-vinylcarboxamide of the formula

in which R ^1, R ² = H or C ₁ - to C ₆ -alkyl, (b) at least one acid group-containing monoethylenically unsaturated monomers and / or their alkali metal, alkaline earth metal or Ammoniumsalalzen, (c) optionally other monoethylenically unsaturated monomers and (d) optionally compounds which have at least two ethylenically unsaturated double bonds in the molecule and subsequent partial or complete cleavage of the groups -CO-R ¹ from the units polymerized in the polymer units of the monomers I to form amino groups, wherein the proportion of the amino groups in Copolymer is at least 10 mol% greater than the proportion of units of acid groups containing monoethylenically unsaturated monomers (b). Method according to one of claims 1 to 10, characterized that as vinylamine units containing polymer polyvinylamine and / or to at least 50 mol% of homopolymers hydrolyzed the N-vinylformamide used. Method according to one of claims 1 to 11, characterized that the vinylamine units containing polymer and the polymers each anionic compound in an amount of 0.1 to 2.0 wt .-%, based is used on dry pulp. Method according to one of claims 1 to 12, characterized that the ratio vinylamine units containing polymer to polymeric anionic Compound 5: 1 to 1: 5. Method according to one of claims 1 to 13, characterized that the ratio vinylamine units containing polymer to polymeric anionic Compound 2: 1 to 1: 2. Method according to one of claims 1 to 14, characterized that is a vinylamine units containing polymer and a polymeric anionic compound a paper stock as a dry strength agent and / or retention and drainage agents separately added. Use of a vinylamine units-containing polymer and a polymeric anionic compound as a dry strength agent and / or retention and dehydrating agent in a process for the production of paper, paperboard and cardboard by separate addition to a pulp, dewatering of the pulp and drying of the paper products, characterized in that as the polymeric anionic compound, at least one copolymer obtainable by copolymerizing (a) at least one N-vinylcarboxamide of the formula

in which R ^1, R ² = H or C ₁ - to C ₆ -alkyl, (b) at least one acid group-containing monoethylenically unsaturated monomers and / or their alkali metal, alkaline earth metal or ammonium salts thereof, (c) optionally other monoethylenically unsaturated monomers and (d) optionally, compounds having at least two ethylenically unsaturated double bonds in the molecule.